Most-cited articles · 2019

The 100 most-cited articles in PeerJ, 2019

Ranked by OpenAlex citation count on 29 October 2026, out of 2,122 eligible articles PeerJ published in 2019. Ranks are frozen; this page will not change. Number one, with 3,776 citations: MetaBAT 2: an adaptive binning algorithm for robust and efficient genome reconstruction from metagenome assemblies.

Cohort
2,122 articles
Listed
Top 100 (4.7%)
Open access
100 of 100
Snapshot
2026-10-29

Ask about these papers

Grounded in this list only, with sources.

3 of 3 free questions left today, no account needed
  1. 1
    top 0.1%

    MetaBAT 2: an adaptive binning algorithm for robust and efficient genome reconstruction from metagenome assemblies

    Dongwan Kang, Feng Li, Edward Kirton, Ashleigh Thomas, Rob S Egan and 2 more

    3,776 citationsOpen access (PUBLIC-DOMAIN)doi:10.7717/peerj.7359OpenAlex

    Show abstract

    We previously reported on MetaBAT, an automated metagenome binning software tool to reconstruct single genomes from microbial communities for subsequent analyses of uncultivated microbial species. MetaBAT has become one of the most popular binning tools largely due to its computational efficiency and ease of use, especially in binning experiments with a large number of samples and a large assembly. MetaBAT requires users to choose parameters to fine-tune its sensitivity and specificity. If those parameters are not chosen properly, binning accuracy can suffer, especially on assemblies of poor quality. Here, we developed MetaBAT 2 to overcome this problem. MetaBAT 2 uses a new adaptive binning algorithm to eliminate manual parameter tuning. We also performed extensive software engineering optimization to increase both computational and memory efficiency. Comparing MetaBAT 2 to alternative software tools on over 100 real world metagenome assemblies shows superior accuracy and computing speed. Binning a typical metagenome assembly takes only a few minutes on a single commodity…

  2. 2
    top 0.1%

    Hierarchical generalized additive models in ecology: an introduction with mgcv

    Eric J. Pedersen, David L. Miller, Gavin L. Simpson, Noam Ross

    1,202 citationsOpen access (CC-BY)doi:10.7717/peerj.6876OpenAlex

    Show abstract

    In this paper, we discuss an extension to two popular approaches to modeling complex structures in ecological data: the generalized additive model (GAM) and the hierarchical model (HGLM). The hierarchical GAM (HGAM), allows modeling of nonlinear functional relationships between covariates and outcomes where the shape of the function itself varies between different grouping levels. We describe the theoretical connection between HGAMs, HGLMs, and GAMs, explain how to model different assumptions about the degree of intergroup variability in functional response, and show how HGAMs can be readily fitted using existing GAM software, the mgcv package in R. We also discuss computational and statistical issues with fitting these models, and demonstrate how to fit HGAMs on example data. All code and data used to generate this paper are available at: github.com/eric-pedersen/mixed-effect-gams .

  3. 3
    top 0.2%

    kuenm: an R package for detailed development of ecological niche models using Maxent

    Marlon E. Cobos, A. Townsend Peterson, Narayani Barve, Luis Osorio‐Olvera

    1,012 citationsOpen access (CC-BY)doi:10.7717/peerj.6281OpenAlex

    Show abstract

    BACKGROUND: Ecological niche modeling is a set of analytical tools with applications in diverse disciplines, yet creating these models rigorously is now a challenging task. The calibration phase of these models is critical, but despite recent attempts at providing tools for performing this step, adequate detail is still missing. Here, we present the kuenm R package, a new set of tools for performing detailed development of ecological niche models using the platform Maxent in a reproducible way. RESULTS: This package takes advantage of the versatility of R and Maxent to enable detailed model calibration and selection, final model creation and evaluation, and extrapolation risk analysis. Best parameters for modeling are selected considering (1) statistical significance, (2) predictive power, and (3) model complexity. For final models, we enable multiple parameter sets and model transfers, making processing simpler. Users can also evaluate extrapolation risk in model transfers via mobility-oriented parity (MOP) metric. DISCUSSION: Use of this package allows robust processes of model…

  4. 4
    top 0.2%

    The impact of artificial intelligence in medicine on the future role of the physician

    Abhimanyu S. Ahuja

    789 citationsOpen access (CC-BY)doi:10.7717/peerj.7702OpenAlex

    Show abstract

    The practice of medicine is changing with the development of new Artificial Intelligence (AI) methods of machine learning. Coupled with rapid improvements in computer processing, these AI-based systems are already improving the accuracy and efficiency of diagnosis and treatment across various specializations. The increasing focus of AI in radiology has led to some experts suggesting that someday AI may even replace radiologists. These suggestions raise the question of whether AI-based systems will eventually replace physicians in some specializations or will augment the role of physicians without actually replacing them. To assess the impact on physicians this research seeks to better understand this technology and how it is transforming medicine. To that end this paper researches the role of AI-based systems in performing medical work in specializations including radiology, pathology, ophthalmology, and cardiology. It concludes that AI-based systems will augment physicians and are unlikely to replace the traditional physician-patient relationship.

  5. 5
    top 0.3%

    Factors affecting the composition of the gut microbiota, and its modulation

    Nihal Hasan, Hongyi Yang

    756 citationsOpen access (CC-BY)doi:10.7717/peerj.7502OpenAlex

    Show abstract

    Gut microbiota have important functions in the body, and imbalances in the composition and diversity of those microbiota can cause several diseases. The host fosters favorable microbiota by releasing specific factors, such as microRNAs, and nonspecific factors, such as antimicrobial peptides, mucus and immunoglobulin A that encourage the growth of specific types of bacteria and inhibit the growth of others. Diet, antibiotics, and age can change gut microbiota, and many studies have shown the relationship between disorders of the microbiota and several diseases and reported some ways to modulate that balance. In this review, we highlight how the host shapes its gut microbiota via specific and nonspecific factors, how environmental and nutritional factors affect it, and how to modulate it using prebiotics, probiotics, and fecal microbiota transplantation.

  6. 6
    top 0.3%

    Breast cancer detection using deep convolutional neural networks and support vector machines

    Dina A. Ragab, Maha Sharkas, Stephen Marshall, Jinchang Ren

    514 citationsOpen access (CC-BY)doi:10.7717/peerj.6201OpenAlex

    Show abstract

    It is important to detect breast cancer as early as possible. In this manuscript, a new methodology for classifying breast cancer using deep learning and some segmentation techniques are introduced. A new computer aided detection (CAD) system is proposed for classifying benign and malignant mass tumors in breast mammography images. In this CAD system, two segmentation approaches are used. The first approach involves determining the region of interest (ROI) manually, while the second approach uses the technique of threshold and region based. The deep convolutional neural network (DCNN) is used for feature extraction. A well-known DCNN architecture named AlexNet is used and is fine-tuned to classify two classes instead of 1,000 classes. The last fully connected (fc) layer is connected to the support vector machine (SVM) classifier to obtain better accuracy. The results are obtained using the following publicly available datasets (1) the digital database for screening mammography (DDSM); and (2) the Curated Breast Imaging Subset of DDSM (CBIS-DDSM). Training on a large number of data…

  7. 7
    top 0.4%

    Adapterama I: universal stubs and primers for 384 unique dual-indexed or 147,456 combinatorially-indexed Illumina libraries (iTru & iNext)

    Travis C. Glenn, Roger Nilsen, Troy J. Kieran, Jon G. Sanders, Natalia J. Bayona‐Vásquez and 16 more

    426 citationsOpen access (CC-BY)doi:10.7717/peerj.7755OpenAlex

    Show abstract

    Massively parallel DNA sequencing offers many benefits, but major inhibitory cost factors include: (1) start-up (i.e., purchasing initial reagents and equipment); (2) buy-in (i.e., getting the smallest possible amount of data from a run); and (3) sample preparation. Reducing sample preparation costs is commonly addressed, but start-up and buy-in costs are rarely addressed. We present dual-indexing systems to address all three of these issues. By breaking the library construction process into universal, re-usable, combinatorial components, we reduce all costs, while increasing the number of samples and the variety of library types that can be combined within runs. We accomplish this by extending the Illumina TruSeq dual-indexing approach to 768 (384 + 384) indexed primers that produce 384 unique dual-indexes or 147,456 (384 × 384) unique combinations. We maintain eight nucleotide indexes, with many that are compatible with Illumina index sequences. We synthesized these indexing primers, purifying them with only standard desalting and placing small aliquots in replicate plates. In…

  8. 8
    top 0.4%

    Validation of COI metabarcoding primers for terrestrial arthropods

    Vasco Elbrecht, Thomas Braukmann, Natalia V. Ivanova, Sean W. J. Prosser, Mehrdad Hajibabaei and 4 more

    332 citationsOpen access (CC-BY)doi:10.7717/peerj.7745OpenAlex

    Show abstract

    Metabarcoding can rapidly determine the species composition of bulk samples and thus aids biodiversity and ecosystem assessment. However, it is essential to use primer sets that minimize amplification bias among taxa to maximize species recovery. Despite this fact, the performance of primer sets employed for metabarcoding terrestrial arthropods has not been sufficiently evaluated. This study tests the performance of 36 primer sets on a mock community containing 374 insect species. Amplification success was assessed with gradient PCRs and the 21 most promising primer sets selected for metabarcoding. These 21 primer sets were also tested by metabarcoding a Malaise trap sample. We identified eight primer sets, mainly those including inosine and/or high degeneracy, that recovered more than 95% of the species in the mock community. Results from the Malaise trap sample were congruent with the mock community, but primer sets generating short amplicons produced potential false positives. Taxon recovery from both mock community and Malaise trap sample metabarcoding were used to select four…

  9. 9
    top 0.5%

    We need to talk about reliability: making better use of test-retest studies for study design and interpretation

    Granville James Matheson

    246 citationsOpen access (CC-BY)doi:10.7717/peerj.6918OpenAlex

    Show abstract

    Neuroimaging, in addition to many other fields of clinical research, is both time-consuming and expensive, and recruitable patients can be scarce. These constraints limit the possibility of large-sample experimental designs, and often lead to statistically underpowered studies. This problem is exacerbated by the use of outcome measures whose accuracy is sometimes insufficient to answer the scientific questions posed. Reliability is usually assessed in validation studies using healthy participants, however these results are often not easily applicable to clinical studies examining different populations. I present a new method and tools for using summary statistics from previously published test-retest studies to approximate the reliability of outcomes in new samples. In this way, the feasibility of a new study can be assessed during planning stages, and before collecting any new data. An R package called relfeas also accompanies this article for performing these calculations. In summary, these methods and tools will allow researchers to avoid performing costly studies which are, by…

  10. 10
    top 0.5%

    A scalable discrete-time survival model for neural networks

    Michael F. Gensheimer, Balasubramanian Narasimhan

    232 citationsOpen access (CC-BY)doi:10.7717/peerj.6257OpenAlex

    Show abstract

    There is currently great interest in applying neural networks to prediction tasks in medicine. It is important for predictive models to be able to use survival data, where each patient has a known follow-up time and event/censoring indicator. This avoids information loss when training the model and enables generation of predicted survival curves. In this paper, we describe a discrete-time survival model that is designed to be used with neural networks, which we refer to as Nnet-survival. The model is trained with the maximum likelihood method using mini-batch stochastic gradient descent (SGD). The use of SGD enables rapid convergence and application to large datasets that do not fit in memory. The model is flexible, so that the baseline hazard rate and the effect of the input data on hazard probability can vary with follow-up time. It has been implemented in the Keras deep learning framework, and source code for the model and several examples is available online. We demonstrate the performance of the model on both simulated and real data and compare it to existing models Cox-nnet…

  11. 11
    top 0.6%

    Exogenous melatonin confers drought stress by promoting plant growth, photosynthetic capacity and antioxidant defense system of maize seedlings

    Shakeel Ahmad, Muhammad Kamran, Ruixia Ding, Xiangping Meng, Haiqi Wang and 3 more

    231 citationsOpen access (CC-BY)doi:10.7717/peerj.7793OpenAlex

    Show abstract

    Melatonin is an important biologically active hormone that plays a vital role in plant growth and development. In particular, it has been investigated for its roles in abiotic stress management. The current experiment was carried out to investigate the protective role of melatonin in photosynthetic traits and the antioxidant defense system of maize seedling under drought stress. Maize seedlings were subjected to drought stress (40-45% FC) after two weeks of seedling emergence, followed by a foliar spray (0, 25, 50, 75 and 100 µM) and soil drench of melatonin (0, 25, 50, 75 and 100 µM). Our results indicated that drought stress negatively affected maize seedling and decreased plant growth and development, biomass accumulation, reduced chlorophyll, and carotenoid content, and significantly declined photosynthetic rate and stomatal conductance. On the other hand, reactive oxygen species, soluble protein, and proline content increased under drought stress. However, the application of exogenous melatonin reduced the reactive oxygen species burst and enhanced the photosynthetic activity…

  12. 12
    top 0.6%

    Combining UAV-based hyperspectral imagery and machine learning algorithms for soil moisture content monitoring

    Xiangyu Ge, Jingzhe Wang, Jianli Ding, Xiaoyi Cao, Zipeng Zhang and 2 more

    230 citationsOpen access (CC-BY)doi:10.7717/peerj.6926OpenAlex

    Show abstract

    Soil moisture content (SMC) is an important factor that affects agricultural development in arid regions. Compared with the space-borne remote sensing system, the unmanned aerial vehicle (UAV) has been widely used because of its stronger controllability and higher resolution. It also provides a more convenient method for monitoring SMC than normal measurement methods that includes field sampling and oven-drying techniques. However, research based on UAV hyperspectral data has not yet formed a standard procedure in arid regions. Therefore, a universal processing scheme is required. We hypothesized that combining pretreatments of UAV hyperspectral imagery under optimal indices and a set of field observations within a machine learning framework will yield a highly accurate estimate of SMC. Optimal 2D spectral indices act as indispensable variables and allow us to characterize a model’s SMC performance and spatial distribution. For this purpose, we used hyperspectral imagery and a total of 70 topsoil samples (0–10 cm) from the farmland (2.5 × 10 4 m 2 ) of Fukang City, Xinjiang Uygur…

  13. 13
    top 0.7%

    The use of biochar in animal feeding

    Hans‐Peter Schmidt, Nikolas Hagemann, Kathleen Draper, Claudia Irene Kammann

    212 citationsOpen access (CC-BY)doi:10.7717/peerj.7373OpenAlex

    Show abstract

    Biochar, that is, carbonized biomass similar to charcoal, has been used in acute medical treatment of animals for many centuries. Since 2010, livestock farmers increasingly use biochar as a regular feed supplement to improve animal health, increase nutrient intake efficiency and thus productivity. As biochar gets enriched with nitrogen-rich organic compounds during the digestion process, the excreted biochar-manure becomes a more valuable organic fertilizer causing lower nutrient losses and greenhouse gas emissions during storage and soil application. Scientists only recently started to investigate the mechanisms of biochar in the different stages of animal digestion and thus most published results on biochar feeding are based so far on empirical studies. This review summarizes the state of knowledge up to the year 2019 by evaluating 112 relevant scientific publications on the topic to derive initial insights, discuss potential mechanisms behind observations and identify important knowledge gaps and future research needs. The literature analysis shows that in most studies and for…

  14. 14
    top 0.7%

    Sleep apnea detection from a single-lead ECG signal with automatic feature-extraction through a modified LeNet-5 convolutional neural network

    Tao Wang, Changhua Lu, Guohao Shen, Feng Hong

    210 citationsOpen access (CC-BY)doi:10.7717/peerj.7731OpenAlex

    Show abstract

    Sleep apnea (SA) is the most common respiratory sleep disorder, leading to some serious neurological and cardiovascular diseases if left untreated. The diagnosis of SA is traditionally made using Polysomnography (PSG). However, this method requires many electrodes and wires, as well as an expert to monitor the test. Several researchers have proposed instead using a single channel signal for SA diagnosis. Among these options, the ECG signal is one of the most physiologically relevant signals of SA occurrence, and one that can be easily recorded using a wearable device. However, existing ECG signal-based methods mainly use features (i.e. frequency domain, time domain, and other nonlinear features) acquired from ECG and its derived signals in order to construct the model. This requires researchers to have rich experience in ECG, which is not common. A convolutional neural network (CNN) is a kind of deep neural network that can automatically learn effective feature representation from training data and has been successfully applied in many fields. Meanwhile, most studies have not…

  15. 15
    top 0.8%

    Performance evaluation of deep neural ensembles toward malaria parasite detection in thin-blood smear images

    Sivaramakrishnan Rajaraman, Stefan Jaeger, Sameer Antani

    200 citationsOpen access (PUBLIC-DOMAIN)doi:10.7717/peerj.6977OpenAlex

    Show abstract

    BACKGROUND: parasites that infect the red blood cells (RBCs). Manual identification and counting of parasitized cells in microscopic thick/thin-film blood examination remains the common, but burdensome method for disease diagnosis. Its diagnostic accuracy is adversely impacted by inter/intra-observer variability, particularly in large-scale screening under resource-constrained settings. INTRODUCTION: State-of-the-art computer-aided diagnostic tools based on data-driven deep learning algorithms like convolutional neural network (CNN) has become the architecture of choice for image recognition tasks. However, CNNs suffer from high variance and may overfit due to their sensitivity to training data fluctuations. OBJECTIVE: The primary aim of this study is to reduce model variance, improve robustness and generalization through constructing model ensembles toward detecting parasitized cells in thin-blood smear images. METHODS: We evaluate the performance of custom and pretrained CNNs and construct an optimal model ensemble toward the challenge of classifying parasitized and normal cells…

  16. 16
    top 0.8%

    A rapid spread of the stony coral tissue loss disease outbreak in the Mexican Caribbean

    Lorenzo Álvarez‐Filip, Nuria Estrada‐Saldívar, Esmeralda Pérez‐Cervantes, Ana Molina‐Hernández, F. Javier González‐Barrios

    192 citationsOpen access (CC-BY)doi:10.7717/peerj.8069OpenAlex

    Show abstract

    Caribbean reef corals have experienced unprecedented declines from climate change, anthropogenic stressors and infectious diseases in recent decades. Since 2014, a highly lethal, new disease, called stony coral tissue loss disease, has impacted many reef-coral species in Florida. During the summer of 2018, we noticed an anomalously high disease prevalence affecting different coral species in the northern portion of the Mexican Caribbean. We assessed the severity of this outbreak in 2018/2019 using the AGRRA coral protocol to survey 82 reef sites across the Mexican Caribbean. Then, using a subset of 14 sites, we detailed information from before the outbreak (2016/2017) to explore the consequences of the disease on the condition and composition of coral communities. Our findings show that the disease outbreak has already spread across the entire region by affecting similar species (with similar disease patterns) to those previously described for Florida. However, we observed a great variability in prevalence and tissue mortality that was not attributable to any geographical gradient.…

  17. 17
    top 0.9%

    Unprofessional peer reviews disproportionately harm underrepresented groups in STEM

    Nyssa J. Silbiger, Amber D. Stubler

    189 citationsOpen access (CC-BY)doi:10.7717/peerj.8247OpenAlex

    Show abstract

    BACKGROUND: Peer reviewed research is paramount to the advancement of science. Ideally, the peer review process is an unbiased, fair assessment of the scientific merit and credibility of a study; however, well-documented biases arise in all methods of peer review. Systemic biases have been shown to directly impact the outcomes of peer review, yet little is known about the downstream impacts of unprofessional reviewer comments that are shared with authors. METHODS: In an anonymous survey of international participants in science, technology, engineering, and mathematics (STEM) fields, we investigated the pervasiveness and author perceptions of long-term implications of receiving of unprofessional comments. Specifically, we assessed authors' perceptions of scientific aptitude, productivity, and career trajectory after receiving an unprofessional peer review. RESULTS: We show that survey respondents across four intersecting categories of gender and race/ethnicity received unprofessional peer review comments equally. However, traditionally underrepresented groups in STEM fields were most…

  18. 18
    top 0.9%

    Adapterama III: Quadruple-indexed, double/triple-enzyme RADseq libraries (2RAD/3RAD)

    Natalia J. Bayona‐Vásquez, Travis C. Glenn, Troy J. Kieran, Todd W. Pierson, Sandra L. Hoffberg and 8 more

    184 citationsOpen access (CC-BY)doi:10.7717/peerj.7724OpenAlex

    Show abstract

    Molecular ecologists frequently use genome reduction strategies that rely upon restriction enzyme digestion of genomic DNA to sample consistent portions of the genome from many individuals (e.g., RADseq, GBS). However, researchers often find the existing methods expensive to initiate and/or difficult to implement consistently, especially because it is difficult to multiplex sufficient numbers of samples to fill entire sequencing lanes. Here, we introduce a low-cost and highly robust approach for the construction of dual-digest RADseq libraries that build on adapters and primers designed in Adapterama I . Major features of our method include: (1) minimizing the number of processing steps; (2) focusing on a single strand of sample DNA for library construction, allowing the use of a non-phosphorylated adapter on one end; (3) ligating adapters in the presence of active restriction enzymes, thereby reducing chimeras; (4) including an optional third restriction enzyme to cut apart adapter-dimers formed by the phosphorylated adapter, thus increasing the efficiency of adapter ligation to…

  19. 19
    top 0.9%

    Kombucha: a novel model system for cooperation and conflict in a complex multi-species microbial ecosystem

    Alexander May, Shrinath Narayanan, Joe Alcock, Arvind Varsani, Carlo C. Maley and 1 more

    184 citationsOpen access (CC-BY)doi:10.7717/peerj.7565OpenAlex

    Show abstract

    Kombucha, a fermented tea beverage with an acidic and effervescent taste, is composed of a multispecies microbial ecosystem with complex interactions that are characterized by both cooperation and conflict. In kombucha, a complex community of bacteria and yeast initiates the fermentation of a starter tea (usually black or green tea with sugar), producing a biofilm that covers the liquid over several weeks. This happens through several fermentative phases that are characterized by cooperation and competition among the microbes within the kombucha solution. Yeast produce invertase as a public good that enables both yeast and bacteria to metabolize sugars. Bacteria produce a surface biofilm which may act as a public good providing protection from invaders, storage for resources, and greater access to oxygen for microbes embedded within it. The ethanol and acid produced during the fermentative process (by yeast and bacteria, respectively) may also help to protect the system from invasion by microbial competitors from the environment. Thus, kombucha can serve as a model system for…

  20. 20
    top 1%

    Unfold: an integrated toolbox for overlap correction, non-linear modeling, and regression-based EEG analysis

    Benedikt Ehinger, Olaf Dimigen

    180 citationsOpen access (CC-BY)doi:10.7717/peerj.7838OpenAlex

    Show abstract

    ABSTRACT Electrophysiological research with event-related brain potentials (ERPs) is increasingly moving from simple, strictly orthogonal stimulation paradigms towards more complex, quasi-experimental designs and naturalistic situations that involve fast, multisensory stimulation and complex motor behavior. As a result, electrophysiological responses from subsequent events often overlap with each other. In addition, the recorded neural activity is typically modulated by numerous covariates, which influence the measured responses in a linear or nonlinear fashion. Examples of paradigms where systematic temporal overlap variations and low-level confounds between conditions cannot be avoided include combined EEG/eye-tracking experiments during natural vision, fast multisensory stimulation experiments, and mobile brain/body imaging studies. However, even “traditional”, highly controlled ERP datasets often contain a hidden mix of overlapping activity (e.g. from stimulus onsets, involuntary microsaccades, or button presses) and it is helpful or even necessary to disentangle these…

  21. 21
    top 1%

    Effects of soil pH and texture on soil carbon and nitrogen in soil profiles under different land uses in Mun River Basin, Northeast Thailand

    Wenxiang Zhou, Guilin Han, Man Liu, Xiaoqiang Li

    166 citationsOpen access (CC-BY)doi:10.7717/peerj.7880OpenAlex

    Show abstract

    Soil carbon and nitrogen are essential factors for agricultural production and climate changes. A total of 106 soil samples from three agricultural lands (including two rice fields and one sugarcane field) and four non-agricultural lands (including two forest lands, one wasteland and one built-up land) in the Mun River Basin were collected to determine soil carbon, nitrogen, soil pH, soil particle sizes and explore the influence of pH and soil texture on soil C and N. The results show that total organic carbon (TOC) and nitrogen (TON) contents in topsoil (TOC: 2.78 ~ 18.83 g kg−1; TON: 0.48 ~ 2.05 g kg−1) are much higher than those in deep soil (TOC: 0.35 ~ 6.08 g kg−1; TON: <0.99 g kg−1). In topsoil, their contents of forest lands and croplands (TOC: average 15.37 g kg−1; TON: average 1.29 g kg−1) are higher than those of other land uses (TOC: average 5.28 g kg−1; TON: average 0.38 g kg−1). The pH values range from 4.2 to 6.1 in topsoil, and with increase in soil depth, they tend to increase and then decrease. Soil carbon, nitrogen and the C/N (TC/TN ratio) are negatively…

  22. 22
    top 1.1%

    Bacillus spp.: potent microfactories of bacterial IAA

    Shabana Wagi, Ambreen Ahmed

    161 citationsOpen access (CC-BY)doi:10.7717/peerj.7258OpenAlex

    Show abstract

    BACKGROUND: Auxin production by bacteria is one of the most important direct mechanisms utilized by plant growth-promoting bacteria (PGPB) for the betterment of plants naturally because auxin is a plant friendly secondary metabolite synthesized naturally by bacteria, and hence improves the growth of associated plants. So, the current study focuses on bacterial synthesis of Indole-3-acetic acid (IAA) for plant growth improvement. METHODS: In the current study, the PGPB were selected on the basis of their auxin production potential and their growth promoting attributes were evaluated. Indole-3-acetic acid producing potential of two selected bacterial isolates was observed by varying different growth conditions i.e., media composition, carbon sources (glucose, sucrose and lactose) and different concentrations of precursor. Influence of various physiological factors (temperature and incubation time period) on IAA production potential was also evaluated. RESULTS: (Mt3b) showed variable potential for the production of bacterial IAA under different set of growth and environmental…

  23. 23
    top 1.1%

    Crowdsourcing in medical research: concepts and applications

    Joseph D. Tucker, Suzanne Day, Weiming Tang, Barry L. Bayus

    158 citationsOpen access (CC-BY)doi:10.7717/peerj.6762OpenAlex

    Show abstract

    Crowdsourcing shifts medical research from a closed environment to an open collaboration between the public and researchers. We define crowdsourcing as an approach to problem solving which involves an organization having a large group attempt to solve a problem or part of a problem, then sharing solutions. Crowdsourcing allows large groups of individuals to participate in medical research through innovation challenges, hackathons, and related activities. The purpose of this literature review is to examine the definition, concepts, and applications of crowdsourcing in medicine. This multi-disciplinary review defines crowdsourcing for medicine, identifies conceptual antecedents (collective intelligence and open source models), and explores implications of the approach. Several critiques of crowdsourcing are also examined. Although several crowdsourcing definitions exist, there are two essential elements: (1) having a large group of individuals, including those with skills and those without skills, propose potential solutions; (2) sharing solutions through implementation or open access…

  24. 24
    top 1.2%

    Characterizing gene tree conflict in plastome-inferred phylogenies

    Joseph F. Walker, Gregory W. Stull, Nathanael Walker‐Hale, Oscar M. Vargas, Drew A. Larson

    149 citationsOpen access (CC-BY)doi:10.7717/peerj.7747OpenAlex

    Show abstract

    ABSTRACT Premise of the study Evolutionary relationships among plants have been inferred primarily using chloroplast data. To date, no study has comprehensively examined the plastome for gene tree conflict. Methods Using a broad sampling of angiosperm plastomes, we characterized gene tree conflict among plastid genes at various time scales and explore correlates to conflict (e.g., evolutionary rate, gene length, molecule type). Key results We uncover notable gene tree conflict against a backdrop of largely uninformative genes. We find gene length is the strongest correlate to concordance, and that nucleotides outperform amino acids. Of the most commonly used markers, matK greatly outperforms rbcL ; however, the rarely used gene rpoC2 is the top-performing gene in every analysis. We find that rpoC2 reconstructs angiosperm phylogeny as well as the entire concatenated set of protein-coding chloroplast genes. Conclusions Our results suggest that longer genes are superior for phylogeny reconstruction. The alleviation of some conflict through the use of nucleotides suggests that…

  25. 25
    top 1.2%

    ConFindr: rapid detection of intraspecies and cross-species contamination in bacterial whole-genome sequence data

    Andrew Low, Adam G. Koziol, Paul Manninger, Burton W. Blais, Catherine D. Carrillo

    147 citationsOpen access (CC-BY)doi:10.7717/peerj.6995OpenAlex

    Show abstract

    Whole-genome sequencing (WGS) of bacterial pathogens is currently widely used to support public-health investigations. The ability to assess WGS data quality is critical to underpin the reliability of downstream analyses. Sequence contamination is a quality issue that could potentially impact WGS-based findings; however, existing tools do not readily identify contamination from closely-related organisms. To address this gap, we have developed a computational pipeline, ConFindr, for detection of intraspecies contamination. ConFindr determines the presence of contaminating sequences based on the identification of multiple alleles of core, single-copy, ribosomal-protein genes in raw sequencing reads. The performance of this tool was assessed using simulated and lab-generated Illumina short-read WGS data with varying levels of contamination (0-20% of reads) and varying genetic distance between the designated target and contaminant strains. Intraspecies and cross-species contamination was reliably detected in datasets containing 5% or more reads from a second, unrelated strain. ConFindr…

  26. 26
    top 1.3%

    Solvent polarity mediates phytochemical yield and antioxidant capacity of Isatis tinctoria

    Abdul Wakeel Umar, Sohail Ahmad Jan, Ikram Ullah, Zabta Khan Shinwari, Ming Xu

    146 citationsOpen access (CC-BY)doi:10.7717/peerj.7857OpenAlex

    Show abstract

    (woad) is elusive. In the present study, 14 solvents with different polarity were used in the extraction and total phenolic and flavonoid content (TPC and TFC) investigation. Ferricyanide, phosphomolybdenum, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods were used to calculate and compare the antioxidant/free radical scavenging capacity. Our results showed that solvent polarity greatly affects TPC and TFC yield, which is mainly increasing with increasing solvent polarity index and suddenly decreasing at very high polarity. The comparative results showed that TPC is directly correlated with reducing power, antioxidant, and free radical scavenging capacity. Taken together, we conclude that different woad plant parts contain different level of secondary metabolites with a specific polarity that requires a particular solvent with an appropriate polarity index for the extraction. The identification of these biologically active crude extracts and fractions are very important for the basic biological sciences, pharmaceutical applications, and future research for HPLC based active…

  27. 27
    top 1.3%

    Long-read viral metagenomics captures abundant and microdiverse viral populations and their niche-defining genomic islands

    Joanna Warwick-Dugdale, Natalie Solonenko, Karen Moore, Lauren Chittick, Ann Gregory and 3 more

    146 citationsOpen access (CC-BY)doi:10.7717/peerj.6800OpenAlex

    Show abstract

    Marine viruses impact global biogeochemical cycles via their influence on host community structure and function, yet our understanding of viral ecology is constrained by limitations in host culturing and a lack of reference genomes and 'universal' gene markers to facilitate community surveys. Short-read viral metagenomic studies have provided clues to viral function and first estimates of global viral gene abundance and distribution, but their assemblies are confounded by populations with high levels of strain evenness and nucleotide diversity (microdiversity), limiting assembly of some of the most abundant viruses on Earth. Such features also challenge assembly across genomic islands containing niche-defining genes that drive ecological speciation. These populations and features may be successfully captured by single-virus genomics and fosmid-based approaches, at least in abundant taxa, but at considerable cost and technical expertise. Here we established a low-cost, low-input, high throughput alternative sequencing and informatics workflow to improve viral metagenomic assemblies…

  28. 28
    top 1.4%

    Embracing heterogeneity: coalescing the Tree of Life and the future of phylogenomics

    Gustavo A. Bravo, Alexandre Antonelli, Christine D. Bacon, Krzysztof Bartoszek, Mozes P. K. Blom and 15 more

    145 citationsOpen access (CC-BY)doi:10.7717/peerj.6399OpenAlex

    Show abstract

    Building the Tree of Life (ToL) is a major challenge of modern biology, requiring advances in cyberinfrastructure, data collection, theory, and more. Here, we argue that phylogenomics stands to benefit by embracing the many heterogeneous genomic signals emerging from the first decade of large-scale phylogenetic analysis spawned by high-throughput sequencing (HTS). Such signals include those most commonly encountered in phylogenomic datasets, such as incomplete lineage sorting, but also those reticulate processes emerging with greater frequency, such as recombination and introgression. Here we focus specifically on how phylogenetic methods can accommodate the heterogeneity incurred by such population genetic processes; we do not discuss phylogenetic methods that ignore such processes, such as concatenation or supermatrix approaches or supertrees. We suggest that methods of data acquisition and the types of markers used in phylogenomics will remain restricted until a posteriori methods of marker choice are made possible with routine whole-genome sequencing of taxa of interest. We…

  29. 29
    top 1.4%

    A new comprehensive eye-tracking test battery concurrently evaluating the Pupil Labs glasses and the EyeLink 1000

    Benedikt Ehinger, Katharina Groß, Inga Ibs, Peter König B

    140 citationsOpen access (CC-BY)doi:10.7717/peerj.7086OpenAlex

    Show abstract

    ABSTRACT Eye-tracking experiments rely heavily on good data quality of eye-trackers. Unfortunately, it is often that only the spatial accuracy and precision values are available from the manufacturers. These two values alone are not sufficient enough to serve as a benchmark for an eye-tracker: Eye-tracking quality deteriorates during an experimental session due to head movements, changing illumination or calibration decay. Additionally, different experimental paradigms require the analysis of different types of eye movements, for instance smooth pursuit movements, blinks or microsaccades, which themselves cannot readily be evaluated by using spatial accuracy or precision alone. To obtain a more comprehensive description of properties, we developed an extensive eye-tracking test battery. In 10 different tasks, we evaluated eye-tracking related measures such as: the decay of accuracy, fixation durations, pupil dilation, smooth pursuit movement, microsaccade detection, blink detection, or the influence of head motion. For some measures, true theoretical values exist. For others, a…

  30. 30
    top 1.5%

    Paenibacillus strains with nitrogen fixation and multiple beneficial properties for promoting plant growth

    Xiaomeng Liu, Qin Li, Yongbin Li, Guohua Guan, Sanfeng Chen

    139 citationsOpen access (CC-BY)doi:10.7717/peerj.7445OpenAlex

    Show abstract

    Paenibacillus is a large genus of Gram-positive, facultative anaerobic, endospore-forming bacteria. The genus Paenibacillus currently comprises more than 150 named species, approximately 20 of which have nitrogen-fixation ability. The N 2 -fixing Paenibacillus strains have potential uses as a bacterial fertilizer in agriculture. In this study, 179 bacterial strains were isolated by using nitrogen-free medium after heating at 85 °C for 10 min from 69 soil samples collected from different plant rhizospheres in different areas. Of the 179 bacterial strains, 25 Paenibacillus strains had nifH gene encoding Fe protein of nitrogenase and showed nitrogenase activities. Of the 25 N 2 -fixing Paenibacillus strains, 22 strains produced indole-3-acetic acid (IAA). 21 strains out of the 25 N 2 -fixing Paenibacillus strains inhibited at least one of the 6 plant pathogens Rhizoctonia cerealis , Fusarium graminearum , Gibberella zeae , Fusarium solani , Colletotrichum gossypii and Alternaria longipes . 18 strains inhibited 5 plant pathogens and Paenibacillus sp. SZ-13b could inhibit the growth of…

  31. 31
    top 1.5%

    Impact of intercropping on the coupling between soil microbial community structure, activity, and nutrient-use efficiencies

    Tengxiang Lian, Yinghui Mu, Jian Jin, Qibin Ma, Yanbo Cheng and 2 more

    132 citationsOpen access (CC-BY)doi:10.7717/peerj.6412OpenAlex

    Show abstract

    Sugarcane-soybean intercropping has been widely used to control disease and improve nutrition in the field. However, the response of the soil microbial community diversity and structure to intercropping is not well understood. Since microbial diversity corresponds to soil quality and plant health, a pot experiment was conducted with sugarcane intercropped with soybean. Rhizosphere soil was collected 40 days after sowing, and MiSeq sequencing was utilized to analyze the soil microbial community diversity and composition. Soil columns were used to assess the influence of intercropping on soil microbial activity (soil respiration and carbon-use efficiency: nitrogen-use efficiency ratio). PICRUSt and FUNGuild analysis were conducted to predict microbial functional profiling. Our results showed that intercropping decreased pH by approximately 8.9% and enhanced the soil organic carbon, dissolved organic carbon, and available nitrogen (N) by 5.5%, 13.4%, and 10.0%, respectively. These changes in physicochemical properties corresponded to increased microbial diversity and shifts in soil…

  32. 32
    top 1.6%

    Prefrontal cortical activation measured by fNIRS during walking: effects of age, disease and secondary task

    Paulo Henrique Silva Pelicioni, Mylou Tijsma, Stephen R. Lord, Jasmine C. Menant

    130 citationsOpen access (CC-BY)doi:10.7717/peerj.6833OpenAlex

    Show abstract

    BACKGROUND: Cognitive processes are required during walking to appropriately respond to environmental and task demands. There are now many studies that have used functional Near-Infrared Spectroscopy (fNIRS) to record brain activation to investigate neural bases of cognitive contributions in gait. The aim of this systematic review was to summarize the published research regarding Prefrontal cortical (PFC) activation patterns during simple and complex walking tasks in young adults, older adults and clinical groups with balance disorders using fNIRS. Our secondary aim was to evaluate each included study based on methodological reporting criteria important for good data quality. METHODS: We conducted searches in June 2018 using four databases: Embase, PubMed, Scopus and PsycINFO. The strategy search used was: (((((near infrared spectroscopy) OR functional near infrared spectroscopy) OR nirs) OR fnirs) AND (((gait) OR walking) OR locomotion) AND (((((young) OR adult) OR older) OR elderly) NOT children)) AND (((Brain) OR cortex) OR cortical) for our search. The papers included met the…

  33. 33
    top 1.6%

    Mitochondrial DNA in human identification: a review

    António Amorim, Teresa Matos Fernandes, Nuno Taveira

    129 citationsOpen access (CC-BY)doi:10.7717/peerj.7314OpenAlex

    Show abstract

    Mitochondrial DNA (mtDNA) presents several characteristics useful for forensic studies, especially related to the lack of recombination, to a high copy number, and to matrilineal inheritance. mtDNA typing based on sequences of the control region or full genomic sequences analysis is used to analyze a variety of forensic samples such as old bones, teeth and hair, as well as other biological samples where the DNA content is low. Evaluation and reporting of the results requires careful consideration of biological issues as well as other issues such as nomenclature and reference population databases. In this work we review mitochondrial DNA profiling methods used for human identification and present their use in the main cases of humanidentification focusing on the most relevant issues for forensics.

  34. 34
    top 1.7%

    Genome-wide identification and transcriptional expression analysis of superoxide dismutase (SOD) family in wheat ( Triticum aestivum )

    Wenqiang J. Jiang, Lei Yang, Yiqin H. He, Haotian Zhang, Wei Li and 3 more

    128 citationsOpen access (CC-BY)doi:10.7717/peerj.8062OpenAlex

    Show abstract

    Superoxide dismutases (SODs) are a family of key antioxidant enzymes that play a crucial role in plant growth and development. Previously, this gene family has been investigated in Arabidopsis and rice. In the present study, a genome-wide analysis of the SOD gene family in wheat were performed. Twenty-six SOD genes were identified from the whole genome of wheat, including 17 Cu/Zn-SODs, six Fe-SODs, and three Mn-SODs. The chromosomal location mapping analysis indicated that these three types of SOD genes were only distributed on 2, 4, and 7 chromosomes, respectively. Phylogenetic analyses of wheat SODs and several other species revealed that these SOD proteins can be assigned to two major categories. SOD1 mainly comprises of Cu/Zn-SODs, and SOD2 mainly comprises of Fe-SODs and Mn-SODs. Gene structure and motif analyses indicated that most of the SOD genes showed a relatively conserved exon/intron arrangement and motif composition. Analyses of transcriptional data indicated that most of the wheat SOD genes were expressed in almost all of the examined tissues and had important…

  35. 35
    top 1.7%

    Adapterama II: universal amplicon sequencing on Illumina platforms (TaggiMatrix)

    Travis C. Glenn, Todd W. Pierson, Natalia J. Bayona‐Vásquez, Troy J. Kieran, Sandra L. Hoffberg and 22 more

    126 citationsOpen access (PUBLIC-DOMAIN)doi:10.7717/peerj.7786OpenAlex

    Show abstract

    Abstract Next-generation sequencing (NGS) of amplicons is used in a wide variety of contexts. Most NGS amplicon sequencing remains overly expensive and inflexible, with library preparation strategies relying upon the fusion of locus-specific primers to full-length adapter sequences with a single identifying sequence or ligating adapters onto PCR products. In Adapterama I , we presented universal stubs and primers to produce thousands of unique index combinations and a modifiable system for incorporating them into Illumina libraries. Here, we describe multiple ways to use the Adapterama system and other approaches for amplicon sequencing on Illumina instruments. In the variant we use most frequently for large-scale projects, we fuse partial adapter sequences (TruSeq or Nextera) onto the 5’ end of locus-specific PCR primers with variable-length tag sequences between the adapter and locus-specific sequences. These fusion primers can be used combinatorially to amplify samples within a 96-well plate (eight forward primers + 12 reverse primers yield 8 × 12 = 96 combinations), and the…

  36. 36
    top 1.7%

    Use of a leaf chlorophyll content index to improve the prediction of above-ground biomass and productivity

    Chuang Liu, Yi Liu, Yanhong Lu, Yulin Liao, Jun Nie and 2 more

    122 citationsOpen access (CC-BY)doi:10.7717/peerj.6240OpenAlex

    Show abstract

    Improving the accuracy of predicting plant productivity is a key element in planning nutrient management strategies to ensure a balance between nutrient supply and demand under climate change. A calculation based on intercepted photosynthetically active radiation is an effective and relatively reliable way to determine the climate impact on a crop above-ground biomass (AGB). This research shows that using variations in a chlorophyll content index (CCI) in a mathematical function could effectively obtain good statistical diagnostic results between simulated and observed crop biomass. In this study, the leaf CCI, which is used as a biochemical photosynthetic component and calibration parameter, increased simulation accuracy across the growing stages during 2016-2017. This calculation improves the accuracy of prediction and modelling of crops under specific agroecosystems, and it may also improve projections of AGB for a variety of other crops.

  37. 37
    top 1.8%

    Phylogeny of Paleozoic limbed vertebrates reassessed through revision and expansion of the largest published relevant data matrix

    David Marjanović, Michel Laurin

    121 citationsOpen access (CC-BY)doi:10.7717/peerj.5565OpenAlex

    Show abstract

    The largest published phylogenetic analysis of early limbed vertebrates (Ruta M, Coates MI. 2007. Journal of Systematic Palaeontology 5:69–122) recovered, for example, Seymouriamorpha, Diadectomorpha and (in some trees) Caudata as paraphyletic and found the “temnospondyl hypothesis” on the origin of Lissamphibia (TH) to be more parsimonious than the “lepospondyl hypothesis” (LH)—though only, as we show, by one step. We report 4,200 misscored cells, over half of them due to typographic and similar accidental errors. Further, some characters were duplicated; some had only one described state; for one, most taxa were scored after presumed relatives. Even potentially continuous characters were unordered, the effects of ontogeny were not sufficiently taken into account, and data published after 2001 were mostly excluded. After these issues are improved—we document and justify all changes to the matrix—but no characters are added, we find (Analysis R1) much longer trees with, for example, monophyletic Caudata, Diadectomorpha and (in some trees) Seymouriamorpha; Ichthyostega either…

  38. 38
    top 1.8%

    A novel GIS-based ensemble technique for flood susceptibility mapping using evidential belief function and support vector machine: Brisbane, Australia

    Mahyat Shafapour Tehrany, Lalit Kumar, Farzin Shabani

    120 citationsOpen access (CC-BY)doi:10.7717/peerj.7653OpenAlex

    Show abstract

    In this study, we propose and test a novel ensemble method for improving the accuracy of each method in flood susceptibility mapping using evidential belief function (EBF) and support vector machine (SVM). The outcome of the proposed method was compared with the results of each method. The proposed method was implemented four times using different SVM kernels. Hence, the efficiency of each SVM kernel was also assessed. First, a bivariate statistical analysis using EBF was performed to assess the correlations among the classes of each flood conditioning factor with flooding. Subsequently, the outcome of the first stage was used in a multivariate statistical analysis performed by SVM. A highest prediction accuracy of 92.11% was achieved by an ensemble EBF-SVM-radial basis function method; the achieved accuracy was 7% and 3% higher than that offered by the individual EBF method and the individual SVM method, respectively. Among all the applied methods, both the individual EBF and SVM methods achieved the lowest accuracies. The reason for the improved accuracy offered by the ensemble…

  39. 39
    top 1.9%

    Brain structural and functional changes in patients with major depressive disorder: a literature review

    Lisong Dai, Hongmei Zhou, Xiangyang Xu, Zhentao Zuo

    118 citationsOpen access (CC-BY)doi:10.7717/peerj.8170OpenAlex

    Show abstract

    Depression is a mental disorder characterized by low mood and anhedonia that involves abnormalities in multiple brain regions and networks. Epidemiological studies demonstrated that depression has become one of the most important diseases affecting human health and longevity. The pathogenesis of the disease has not been fully elucidated. The clinical effect of treatment is not satisfactory in many cases. Neuroimaging studies have provided rich and valuable evidence that psychological symptoms and behavioral deficits in patients with depression are closely related to structural and functional abnormalities in specific areas of the brain. There were morphological differences in several brain regions, including the frontal lobe, temporal lobe, and limbic system, in people with depression compared to healthy people. In addition, people with depression also had abnormal functional connectivity to the default mode network, the central executive network, and the salience network. These findings provide an opportunity to re-understand the biological mechanisms of depression. In the future,…

  40. 40
    top 1.9%

    Oxidative stress as a potential target in acute kidney injury

    Anamaria Tomşa, Alexandru Leonard Alexa, Lia Monica Junie, Andreea Liana Răchişan, Lorena Ciumărnean

    112 citationsOpen access (CC-BY)doi:10.7717/peerj.8046OpenAlex

    Show abstract

    BACKGROUND: Acute kidney injury (AKI) is a major problem for health systems being directly related to short and long-term morbidity and mortality. In the last years, the incidence of AKI has been increasing. AKI and chronic kidney disease (CKD) are closely interconnected, with a growing rate of CKD linked to repeated and severe episodes of AKI. AKI and CKD can occur also secondary to imbalanced oxidative stress (OS) reactions, inflammation, and apoptosis. The kidney is particularly sensitive to OS. OS is known as a crucial pathogenetic factor in cellular damage, with a direct role in initiation, development, and progression of AKI. The aim of this review is to focus on the pathogenetic role of OS in AKI in order to gain a better understanding. We exposed the potential relationships between OS and the perturbation of renal function and we also presented the redox-dependent factors that can contribute to early kidney injury. In the last decades, promising advances have been made in understanding the pathophysiology of AKI and its consequences, but more studies are needed in order to…

  41. 41
    top 2%

    Application of built-in adjuvants for epitope-based vaccines

    Yao Lei, Furong Zhao, Junjun Shao, Yangfan Li, Shifang Li and 2 more

    112 citationsOpen access (CC-BY)doi:10.7717/peerj.6185OpenAlex

    Show abstract

    Several studies have shown that epitope vaccines exhibit substantial advantages over conventional vaccines. However, epitope vaccines are associated with limited immunity, which can be overcome by conjugating antigenic epitopes with built-in adjuvants (e.g., some carrier proteins or new biomaterials) with special properties, including immunologic specificity, good biosecurity and biocompatibility, and the ability to vastly improve the immune response of epitope vaccines. When designing epitope vaccines, the following types of built-in adjuvants are typically considered: (1) pattern recognition receptor ligands (i.e., toll-like receptors); (2) virus-like particle carrier platforms; (3) bacterial toxin proteins; and (4) novel potential delivery systems (e.g., self-assembled peptide nanoparticles, lipid core peptides, and polymeric or inorganic nanoparticles). This review primarily discusses the current and prospective applications of these built-in adjuvants (i.e., biological carriers) to provide some references for the future design of epitope-based vaccines.

  42. 42
    top 2%

    Transcription factors involved in abiotic stress responses in Maize ( Zea mays L.) and their roles in enhanced productivity in the post genomics era

    Roy Njoroge Kimotho, Elamin Hafiz Baillo, Zhengbin Zhang

    111 citationsOpen access (CC-BY)doi:10.7717/peerj.7211OpenAlex

    Show abstract

    BACKGROUND: L.) is a principal cereal crop cultivated worldwide for human food, animal feed, and more recently as a source of biofuel. However, as a direct consequence of water insufficiency and climate change, frequent occurrences of both biotic and abiotic stresses have been reported in various regions around the world, and recently, this has become a constant threat in increasing global maize yields. Plants respond to abiotic stresses by utilizing the activities of transcription factors (TFs), which are families of genes coding for specific TF proteins. TF target genes form a regulon that is involved in the repression/activation of genes associated with abiotic stress responses. Therefore, it is of utmost importance to have a systematic study on each TF family, the downstream target genes they regulate, and the specific TF genes involved in multiple abiotic stress responses in maize and other staple crops. METHOD: In this review, the main TF families, the specific TF genes and their regulons that are involved in abiotic stress regulation will be briefly discussed. Great emphasis…

  43. 43
    top 2.1%

    Variations in ecosystem service value in response to land use/land cover changes in Central Asia from 1995–2035

    Jiangyue Li, Hongxing Chen, Chi Zhang, Tao Pan

    110 citationsOpen access (CC-BY)doi:10.7717/peerj.7665OpenAlex

    Show abstract

    Acute farmland expansion and rapid urbanization in Central Asia have accelerated land use/land cover changes, which have substantial effects on ecosystem services. However, the spatiotemporal variations in ecosystem service values (ESVs) in Central Asia are not well understood. Here, based on land use products with 300-m resolution for the years 1995, 2005 and 2015 and transfer methodology, we predicted land use and land cover (LULC) for 2025 and 2035 using CA-Markov, assessed changes in ESVs in response to LULC dynamics, and explored the elasticity of the response of ESV to LULC changes. We found significant expansions of cropland (+22.10%) and urban areas (+322.40%) and shrinking of water bodies (-38.43%) and bare land (-9.42%) during 1995-2035. The combined value of ecosystem services of water bodies, cropland, and grassland accounted for over 90% of the total ESVs. Our study showed that cropland ecosystem services value increased by 93.45 billion US$ from 1995 to 2035, which was mainly caused by the expansion of cropland area. However, the area of water bodies decreased sharply…

  44. 44
    top 2.1%

    Prevalence of generalized joint hypermobility, musculoskeletal injuries, and chronic musculoskeletal pain among American university students

    Peter Robert Reuter, Kaylee R. Fichthorn

    110 citationsOpen access (CC-BY)doi:10.7717/peerj.7625OpenAlex

    Show abstract

    The objective of this study was to investigate the prevalence of generalized joint hypermobility (GJH) in a university-aged population, whether young adults (aged 18-25 years) with GJH are prone to sustain more musculoskeletal injuries, and are more likely to suffer from chronic musculoskeletal pain. The study used an interactive survey to gather data; GJH was assessed using a cut-off Beighton score of ≥5 in accordance with the 2017 International Classification of EDS criteria. The analyzed sample consisted of 482 female and 172 male participants from Florida Gulf Coast University (USA). The prevalence of GJH in a university-aged population can be estimated at 12.5%. Women did not have higher rates of GJH than men. However, female participants showed significantly higher rates of hypermobility of the spine as well as the right knee and elbow joints. The Beighton scores did not differ by ethnicity/race. Female participants had a lower rate of self-reported injuries than male participants, although this difference was not significant. There was no difference in the proportion of all…

  45. 45
    top 2.2%

    An integration of deep learning with feature embedding for protein–protein interaction prediction

    Yu Yao, Xiuquan Du, Yanyu Diao, Huaixu Zhu

    108 citationsOpen access (CC-BY)doi:10.7717/peerj.7126OpenAlex

    Show abstract

    Protein-protein interactions are closely relevant to protein function and drug discovery. Hence, accurately identifying protein-protein interactions will help us to understand the underlying molecular mechanisms and significantly facilitate the drug discovery. However, the majority of existing computational methods for protein-protein interactions prediction are focused on the feature extraction and combination of features and there have been limited gains from the state-of-the-art models. In this work, a new residue representation method named Res2vec is designed for protein sequence representation. Residue representations obtained by Res2vec describe more precisely residue-residue interactions from raw sequence and supply more effective inputs for the downstream deep learning model. Combining effective feature embedding with powerful deep learning techniques, our method provides a general computational pipeline to infer protein-protein interactions, even when protein structure knowledge is entirely unknown. The proposed method DeepFE-PPI is evaluated on the S. Cerevisiae and human…

  46. 46
    top 2.2%

    Effect of dietary concentrate to forage ratio on growth performance, rumen fermentation and bacterial diversity of Tibetan sheep under barn feeding on the Qinghai-Tibetan plateau

    Hongjin Liu, Tianwei Xu, Shixiao Xu, Li Ma, Xueping Han and 7 more

    107 citationsOpen access (CC-BY)doi:10.7717/peerj.7462OpenAlex

    Show abstract

    This study aimed to research the effects of different dietary concentrate to forage (C:F) ratio on growth performance, rumen fermentation and bacteria diversity of barn feeding Tibetan sheep. The experiment contains fiver treatments (HS1, HS2 HS3, HS4 and HS5; n = 8, respectively) based on dietary C:F ratios 0:100, 15:85, 30:70, 45:55, and 60:40, respectively. The ruminal bacterial community structure was investigated through high-throughput sequencing of 16S rRNA genes in V4 hypervariable region. The results showed that increasing dietary concentrate feed level from 0% to 60% exerted a positive effect on DMI, BW gain, gain rate and feed conversation ratio (F CR ) in Tibetan sheep. The increases dietary concentrate feed level elevatedNH 3 -N, propionate and valerate concentrations, whereas, reduced molar ratio of acetate to propionate (A/P ratio) ( P < 0.05). For rumen bacterial diversity, increases in dietary concentrate content contributed to lower alpha diversity indexes including Shannon wiener, Chao1 and observed species, meanwhile, significantly increased the abundances of the…

  47. 47
    top 2.3%

    Gnathovorax cabreirai : a new early dinosaur and the origin and initial radiation of predatory dinosaurs

    Cristian Pereira Pacheco, Rodrigo Temp Müller, Max C. Langer, Flávio Augusto Pretto, Leonardo R. Kerber and 1 more

    105 citationsOpen access (CC-BY)doi:10.7717/peerj.7963OpenAlex

    Show abstract

    Predatory dinosaurs were an important ecological component of terrestrial Mesozoic ecosystems. Though theropod dinosaurs carried this role during the Jurassic and Cretaceous Periods (and probably the post-Carnian portion of the Triassic), it is difficult to depict the Carnian scenario, due to the scarcity of fossils. Until now, knowledge on the earliest predatory dinosaurs mostly relies on herrerasaurids recorded in Carnian strata of South America. Phylogenetic investigations recovered the clade in different positions within Dinosauria, whereas fewer studies challenged its monophyly. Although herrerasaurid fossils are much better recorded in present-day Argentina than in Brazil, Argentinean strata so far yielded no fairly complete skeleton representing a single individual. Here, we describe Gnathovorax cabreirai , a new herrerasaurid based on an exquisite specimen found as part of a multitaxic association form southern Brazil. The type specimen comprises a complete and well-preserved articulated skeleton, preserved in close association (side by side) with rhynchosaur and cynodont…

  48. 48
    top 2.3%

    Preoperative inflammatory markers of NLR and PLR as indicators of poor prognosis in resectable HCC

    Dong Wang, Ning Bai, Xi Hu, Xi Ouyang, Lei Yao and 2 more

    105 citationsOpen access (CC-BY)doi:10.7717/peerj.7132OpenAlex

    Show abstract

    BACKGROUND: Many recent studies have demonstrated the predominant role chronic inflammation plays in cancer cell propagation, angiogenesis and immunosuppression. Cancer-related inflammation (CRI) has been shown to correlate with poor cancer prognosis. Our study aimed to evaluate the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in patients with hepatocellular carcinoma (HCC) who have undergone liver resection. METHODS: Between 2012 and 2015, 239 patients with HCC who had undergone liver resection at XiangYa Hospital Central South University were included in this study. The values of simple inflammatory markers, including the NLR and PLR, used in predicting the long-term outcomes of these patients were evaluated using Kaplan-Meier curves and Cox regression models. RESULTS: The cutoff values of the NLR and PLR were 2.92 and 128.1, respectively. In multivariate Cox regression analysis, high NLR (≥2.92) and high PLR (≥128.1) were independent risk factors predicting poorer outcomes in patients with HCC. However, high NLR and high PLR…

  49. 49
    top 2.4%

    Identification of crucial genes in abdominal aortic aneurysm by WGCNA

    Siliang Chen, Dan Yang, Chuxiang Lei, Yuan Li, Xiaoning Sun and 3 more

    105 citationsOpen access (CC-BY)doi:10.7717/peerj.7873OpenAlex

    Show abstract

    BACKGROUND: Abdominal aortic aneurysm (AAA) is the full thickness dilation of the abdominal aorta. However, few effective medical therapies are available. Thus, elucidating the molecular mechanism of AAA pathogenesis and exploring the potential molecular target of medical therapies for AAA is of vital importance. METHODS: Three expression datasets (GSE7084, GSE47472 and GSE57691) were downloaded from the Gene Expression Omnibus (GEO). These datasets were merged and then normalized using the "sva" R package. Differential expressed gene (DEG) analysis and weighted gene co-expression network analysis (WGCNA) were conducted. We compared the co-expression patterns between AAA and normal conditions, and hub genes of each functional module were identified. DEGs were mapped to co-expression network under AAA condition and a DEG co-expression network was generated. Crucial genes were identified using molecular complex detection (MCODE) (a plugin in Cytoscape). RESULTS: In our study, 6 and 10 gene modules were detected for the AAA and normal conditions, respectively, while 143 DEGs were…

  50. 50
    top 2.4%

    DeepBindRG: a deep learning based method for estimating effective protein–ligand affinity

    Haiping Zhang, Linbu Liao, Konda Mani Saravanan, Peng Yin, Yanjie Wei

    105 citationsOpen access (CC-BY)doi:10.7717/peerj.7362OpenAlex

    Show abstract

    Proteins interact with small molecules to modulate several important cellular functions. Many acute diseases were cured by small molecule binding in the active site of protein either by inhibition or activation. Currently, there are several docking programs to estimate the binding position and the binding orientation of protein–ligand complex. Many scoring functions were developed to estimate the binding strength and predict the effective protein–ligand binding. While the accuracy of current scoring function is limited by several aspects, the solvent effect, entropy effect, and multibody effect are largely ignored in traditional machine learning methods. In this paper, we proposed a new deep neural network-based model named DeepBindRG to predict the binding affinity of protein–ligand complex, which learns all the effects, binding mode, and specificity implicitly by learning protein–ligand interface contact information from a large protein–ligand dataset. During the initial data processing step, the critical interface information was preserved to make sure the input is suitable for…

  51. 51
    top 2.5%

    Recent updates on metabolite composition and medicinal benefits of mangosteen plant

    Wan Mohd Aizat, Ili Nadhirah Jamil, Faridda Hannim Ahmad-Hashim, Normah Mohd Noor

    105 citationsOpen access (CC-BY)doi:10.7717/peerj.6324OpenAlex

    Show abstract

    BACKGROUND: L.) fruit has a unique sweet-sour taste and is rich in beneficial compounds such as xanthones. Mangosteen originally been used in various folk medicines to treat diarrhea, wounds, and fever. More recently, it had been used as a major component in health supplement products for weight loss and for promoting general health. This is perhaps due to its known medicinal benefits, including as anti-oxidant and anti-inflammation. Interestingly, publications related to mangosteen have surged in recent years, suggesting its popularity and usefulness in research laboratories. However, there are still no updated reviews (up to 2018) in this booming research area, particularly on its metabolite composition and medicinal benefits. METHOD: In this review, we have covered recent articles within the years of 2016 to 2018 which focus on several aspects including the latest findings on the compound composition of mangosteen fruit as well as its medicinal usages. RESULT: Mangosteen has been vastly used in medicinal areas including in anti-cancer, anti-microbial, and anti-diabetes…

  52. 52
    top 2.5%

    Improved taxonomic assignment of rumen bacterial 16S rRNA sequences using a revised SILVA taxonomic framework

    Gemma Henderson, Pelin Yilmaz, Sandeep Kumar, Robert J. Forster, William J. Kelly and 3 more

    104 citationsOpen access (CC-BY)doi:10.7717/peerj.6496OpenAlex

    Show abstract

    The taxonomy and associated nomenclature of many taxa of rumen bacteria are poorly defined within databases of 16S rRNA genes. This lack of resolution results in inadequate definition of microbial community structures, with large parts of the community designated as incertae sedis, unclassified, or uncultured within families, orders, or even classes. We have begun resolving these poorly-defined groups of rumen bacteria, based on our desire to name these for use in microbial community profiling. We used the previously-reported global rumen census (GRC) dataset consisting of >4.5 million partial bacterial 16S rRNA gene sequences amplified from 684 rumen samples and representing a wide range of animal hosts and diets. Representative sequences from the 8,985 largest operational units (groups of sequence sharing >97% sequence similarity, and covering 97.8% of all sequences in the GRC dataset) were used to identify 241 pre-defined clusters (mainly at genus or family level) of abundant rumen bacteria in the ARB SILVA 119 framework. A total of 99 of these clusters (containing 63.8% of all…

  53. 53
    top 2.5%

    Optimizing plant density and nitrogen application to manipulate tiller growth and increase grain yield and nitrogen-use efficiency in winter wheat

    Dongqing Yang, Tommaso Cai, Yongli Luo, Zhenlin Wang

    103 citationsOpen access (CC-BY)doi:10.7717/peerj.6484OpenAlex

    Show abstract

    The growth of wheat tillers and plant nitrogen-use efficiency (NUE) will gradually deteriorate in response to high plant density and over-application of N. Therefore, in this study, a 2-year field study was conducted with three levels of plant densities (75 ×104plants ha−1, D1; 300 ×104plants ha−1, D2; 525 ×104plants ha−1, D3) and three levels of N application rates (120 kg N ha−1, N1; 240 kg N ha−1, N2; 360 kg N ha−1, N3) to determine how to optimize plant density and N application to regulate tiller growth and to assess the contribution of such measures to enhancing grain yield (GY) and NUE. The results indicated that an increase in plant density significantly increased the number of superior tillers and the number of spikes per m2(SN), resulting in a higher GY and higher partial factor productivity of applied N (PFPN). However, there was no significant difference in GY and PFPNbetween plant densities D2 and D3. Increasing the N application rate significantly increased the vascular bundle number (NVB) and area (AVB), however, excess N application (N3) did not significantly improve…

  54. 54
    top 2.6%

    Comparison of the National Early Warning Score (NEWS) and the Modified Early Warning Score (MEWS) for predicting admission and in-hospital mortality in elderly patients in the pre-hospital setting and in the emergency department

    Toshiya Mitsunaga, Izumu Hasegawa, Masahiko Uzura, Kenji Okuno, Kei Otani and 3 more

    101 citationsOpen access (CC-BY)doi:10.7717/peerj.6947OpenAlex

    Show abstract

    The aim of this study is to evaluate the usefulness of the pre-hospital National Early Warning Score (pNEWS) and the pre-hospital Modified Early Warning Score (pMEWS) for predicting admission and in-hospital mortality in elderly patients presenting to the emergency department (ED). We also compare the value of the pNEWS with that of the ED NEWS (eNEWS) and ED MEWS (eMEWS) for predicting admission and in-hospital mortality. This retrospective, single-centre observational study was carried out in the ED of Jikei University Kashiwa Hospital, in Chiba, Japan, from 1st April 2017 to 31st March 2018. All patients aged 65 years or older were included in this study. The pNEWS/eNEWS were derived from seven common physiological vital signs: respiratory rate, peripheral oxygen saturation, the presence of inhaled oxygen parameters, body temperature, systolic blood pressure, pulse rate and Alert, responds to Voice, responds to Pain, Unresponsive (AVPU) score, whereas the pMEWS/eMEWS were derived from six common physiological vital signs: respiratory rate, peripheral oxygen saturation, body…

  55. 55
    top 2.6%

    Quantitative color profiling of digital images with earth mover’s distance using the R package colordistance

    Hannah I. Weller, Mark W. Westneat

    101 citationsOpen access (CC-BY)doi:10.7717/peerj.6398OpenAlex

    Show abstract

    Biological color may be adaptive or incidental, seasonal or permanent, species- or population-specific, or modified for breeding, defense or camouflage. Although color is a hugely informative aspect of biology, quantitative color comparisons are notoriously difficult. Color comparison is limited by categorization methods, with available tools requiring either subjective classifications, or expensive equipment, software, and expertise. We present an R package for processing images of organisms (or other objects) in order to quantify color profiles, gather color trait data, and compare color palettes on the basis of color similarity and amount. The package treats image pixels as 3D coordinates in a "color space," producing a multidimensional color histogram for each image. Pairwise distances between histograms are computed using earth mover's distance, a technique borrowed from computer vision, that compares histograms using transportation costs. Users choose a color space, parameters for generating color histograms, and a pairwise comparison method to produce a color distance matrix…

  56. 56
    top 2.7%

    A new small device made of glass for separating microplastics from marine and freshwater sediments

    Ryota Nakajima, Masashi Tsuchiya, DHUGAL JOHN LINDSAY, Tomo Kitahashi, Katsunori Fujikura and 1 more

    100 citationsOpen access (CC-BY)doi:10.7717/peerj.7915OpenAlex

    Show abstract

    Separating microplastics from marine and freshwater sediments is challenging, but necessary to determine their distribution, mass, and ecological impacts in benthic environments. Density separation is commonly used to extract microplastics from sediments by using heavy salt solutions, such as zinc chloride and sodium iodide. However, current devices/apparatus used for density separation, including glass beakers, funnels, upside-down funnel-shaped separators with a shut-off valve, etc., possess various shortcomings in terms of recovery rate, time consumption, and/or usability. In evaluating existing microplastic extraction methods using density separation, we identified the need for a device that allows rapid, simple, and efficient extraction of microplastics from a range of sediment types. We have developed a small glass separator, without a valve, taking a hint from an Utermöhl chamber. This new device is easy to clean and portable, yet enables rapid separation of microplastics from sediments. With this simple device, we recovered 94-98% of <1,000 µm microplastics (polyethylene,…

  57. 57
    top 2.7%

    The nectar report: quantitative review of nectar sugar concentrations offered by bee visited flowers in agricultural and non-agricultural landscapes

    Tobias Pamminger, Roland Becker, Sophie Himmelreich, Christof W. Schneider, Matthias Bergtold

    100 citationsOpen access (CC-BY)doi:10.7717/peerj.6329OpenAlex

    Show abstract

    There is growing concern that some bee populations are in decline, potentially threatening pollination security in agricultural and non-agricultural landscapes. Among the numerous causes associated with this trend, nutritional stress resulting from a mismatch between bee nutritional needs and plant community provisioning has been suggested as one potential driver. To ease nutritional stress on bee populations in agricultural habitats, agri-environmental protection schemes aim to provide alternative nutritional resources for bee populations during times of need. However, such efforts have focused mainly on quantity (providing flowering plants) and timing (during flower-scarce periods), while largely ignoring the quality of the offered flower resources. In a first step to start addressing this information gap, we have used literature data to compile a comprehensive geographically explicit dataset on nectar quality (i.e., total sugar concentration), offered to bees both within fields (crop and weed species) as well as outside fields (wild species) around the globe. Social bees are…

  58. 58
    top 2.8%

    Comparative characterization of biochars produced at three selected pyrolysis temperatures from common woody and herbaceous waste streams

    Matthew Askeland, Bradley O. Clarke, Jorge Paz‐Ferreiro

    98 citationsOpen access (CC-BY)doi:10.7717/peerj.6784OpenAlex

    Show abstract

    Biochar, the product of biomass pyrolysis, has been explored as a soil amendment and carbon capture vessel. Recent literature has aligned biochar as a novel sorbent for a host of environmental contaminants. Through the variation of pyrolysis conditions, biochars can be engineered to have qualities desirable in sorbents whilst maintaining their agronomic benefits. This study focuses on identifying the effects that feedstock type and process temperature have on biochar characteristics which may in turn shed light on their potential environmental applications. Using this approach, six biochars were created from two waste biomasses. The biochars exhibited wide ranges of pH (5.6–11.1), surface area (16.2–397.4 m 2 /g), electrical conductivity (19–2,826 µS/cm), fixed carbon (72–97%), heavy metal and polycyclic aromatic hydrocarbons (PAHs). Statistically significant trends ( P < 0.05) in biochar characteristics dependent upon increasing pyrolysis temperature and feedstock type were identified. Arsenic (>13 mg/kg), chromium (>93 mg/kg), copper (>143 mg/kg) and PAH (>6 mg/kg) concentrations…

  59. 59
    top 2.8%

    Pangenomic type III effector database of the plant pathogenic Ralstonia spp.

    Cyrus Raja Rubenstein Sabbagh, Sébastien Carrère, Fabien Lonjon, Fabienne Vailleau, Alberto P. Macho and 2 more

    97 citationsOpen access (CC-BY)doi:10.7717/peerj.7346OpenAlex

    Show abstract

    Background The bacterial plant pathogenic Ralstonia species belong to the beta-proteobacteria class and are soil-borne pathogens causing vascular bacterial wilt disease, affecting a wide range of plant hosts. These bacteria form a heterogeneous group considered as a “species complex” gathering three newly defined species. Like many other Gram negative plant pathogens, Ralstonia pathogenicity relies on a type III secretion system, enabling bacteria to secrete/inject a large repertoire of type III effectors into their plant host cells. Type III-secreted effectors (T3Es) are thought to participate in generating a favorable environment for the pathogen (countering plant immunity and modifying the host metabolism and physiology). Methods Expert genome annotation, followed by specific type III-dependent secretion, allowed us to improve our Hidden-Markov-Model and Blast profiles for the prediction of type III effectors. Results We curated the T3E repertoires of 12 plant pathogenic Ralstonia strains, representing a total of 12 strains spread over the different groups of the species complex.…

  60. 60
    top 2.9%

    Vehicle emission and atmospheric pollution in China: problems, progress, and prospects

    Jin Wang, Qiuxia Wu, Juan Liu, Hong Yang, Meiling Yin and 6 more

    97 citationsOpen access (CC-BY)doi:10.7717/peerj.6932OpenAlex

    Show abstract

    China has been the largest vehicle market in the world since 2009. The stalemate between the rapid development of the vehicle industry and delayed vehicle emission control has become increasingly prominent. Vehicle emission has become a significant source of air pollution in China's cities. Understanding the current barriers in the vehicle industry is necessary for the development of effective and sustainable measures and policy to manage vehicle-induced air pollution. This review provides insight into the circumstances and causes of vehicle-induced air pollution and outlines recent progress in policy-makers' long-term strategies and regulations. The development of an integrated mechanism of social participation, technical revolution, and regulatory innovation in vehicles, fuel, and roads is suggested to break the stalemate between air pollution and the automobile boom in China; the implications of this review extend to other countries facing the similar atmospheric pollution problems.

  61. 61
    top 2.9%

    Sargassum blooms in the Caribbean alter the trophic structure of the sea urchin Diadema antillarum

    Nancy Cabañillas-Terán, Héctor A. Hernández‐Arana, Miguel-Ángel Ruíz-Zárate, Alejandro Vega‐Zepeda, Alberto Sánchez

    96 citationsOpen access (CC-BY)doi:10.7717/peerj.7589OpenAlex

    Show abstract

    The arrival of large masses of drifting Sargassum since 2011 has caused changes in the natural dynamics of Caribbean coastal ecosystems. In the summer of 2015, unprecedented and massive mats of S. fluitans and S. natans have been observed throughout the Mexican Caribbean including exceptional accumulations ashore. This study uses stable isotopes to assess the impact of Sargassum blooms on the trophic dynamics of the Diadema antillarum sea urchin, a keystone herbivore on many Caribbean reefs. Bayesian models were used to estimate the variations in the relative proportions of carbon and nitrogen of assimilated algal resources. At three lagoon reef sites, the niche breadth of D. antillarum was analysed and compared under massive influx of drifting Sargassum spp. vs. no influx of Sargassum blooms. The effects of the leachates generated by the decomposition of Sargassum led to hypoxic conditions on these reefs and reduced the taxonomic diversity of macroalgal food sources available to D. antillarum . Our trophic data support the hypothesis that processes of assimilation of carbon and…

  62. 62
    top 3%

    Characterisation of bacteria isolated from the stingless bee, Heterotrigona itama , honey, bee bread and propolis

    Mohamad Syazwan Ngalimat, Raja Noor Zaliha Raja Abd Rahman, Mohd Termizi Yusof, Amir Syahir, Suriana Sabri

    95 citationsOpen access (CC-BY)doi:10.7717/peerj.7478OpenAlex

    Show abstract

    Bacteria are present in stingless bee nest products. However, detailed information on their characteristics is scarce. Thus, this study aims to investigate the characteristics of bacterial species isolated from Malaysian stingless bee, Heterotrigona itama , nest products. Honey, bee bread and propolis were collected aseptically from four geographical localities of Malaysia. Total plate count (TPC), bacterial identification, phenotypic profile and enzymatic and antibacterial activities were studied. The results indicated that the number of TPC varies from one location to another. A total of 41 different bacterial isolates from the phyla Firmicutes, Proteobacteria and Actinobacteria were identified. Bacillus species were the major bacteria found. Therein, Bacillus cereus was the most frequently isolated species followed by Bacillus aryabhattai , Bacillus oleronius , Bacillus stratosphericus , Bacillus altitudinis , Bacillus amyloliquefaciens , Bacillus nealsonii , Bacillus toyonensis , Bacillus subtilis , Bacillus safensis , Bacillus pseudomycoides , Enterobacter asburiae ,…

  63. 63
    top 3%

    The effects of spatial and temporal replicate sampling on eDNA metabarcoding

    Kevin K. Beentjes, Arjen G. C. L. Speksnijder, Menno Schilthuizen, Marten Hoogeveen, Berry van der Hoorn

    94 citationsOpen access (CC-BY)doi:10.7717/peerj.7335OpenAlex

    Show abstract

    BACKGROUND: The heterogeneous nature of environmental DNA (eDNA) and its effects on species detection and community composition estimates has been highlighted in several studies in the past decades. Mostly in the context of spatial distribution over large areas, in fewer occasions looking at spatial distribution within a single body of water. Temporal variation of eDNA, similarly, has mostly been studied as seasonality, observing changes over large periods of time, and often only for small groups of organisms such as fish and amphibians. METHODS: We analyzed and compared small-scale spatial and temporal variation by sampling eDNA from two small, isolated dune lakes for 20 consecutive weeks. Metabarcoding was performed on the samples using generic COI primers. Molecular operational taxonomic unit (MOTUs) were used to assess dissimilarities between spatial and temporal replicates. RESULTS: Our results show large differences between samples taken within one lake at one point in time, but also expose the large differences between temporal replicates, even those taken only 1 week apart.…

  64. 64
    top 3.1%

    Optical microscopic study of surface morphology and filtering efficiency of face masks

    Bhanu Bhakta Neupane, Sangita Mainali, Amita Sharma, Basant Giri

    94 citationsOpen access (CC-BY)doi:10.7717/peerj.7142OpenAlex

    Show abstract

    BACKGROUND: Low-cost face masks made from different cloth materials are very common in developing countries. The cloth masks (CM) are usually double layered with stretchable ear loops. It is common practice to use such masks for months after multiple washing and drying cycles. If a CM is used for long time, the ear loops become stretched. The loop needs to be knotted to make the mask loop fit better on the face. It is not clear how washing and drying and stretching practices change the quality of a CM. The particulate matter (PM) filtering efficiency of a mask depends on multiple parameters, such as pore size, shape, clearance, and pore number density. It is important to understand the effect of these parameters on the filtering efficiency. METHODS: We characterized the surface of twenty different types of CMs using optical image analysis method. The filtering efficiency of selected cloth face masks was measured using the particle counting method. We also studied the effects of washing and drying and stretching on the quality of a mask. RESULTS: filtering efficiency of four of the…

  65. 65
    top 3.1%

    Genome skimming is a low-cost and robust strategy to assemble complete mitochondrial genomes from ethanol preserved specimens in biodiversity studies

    Bruna Trevisan, Daniel Máximo Corrêa Alcântara, Denis Jacob Machado, Fernando P. L. Marques, Daniel J. G. Lahr

    92 citationsOpen access (CC-BY)doi:10.7717/peerj.7543OpenAlex

    Show abstract

    Global loss of biodiversity is an ongoing process that concerns both local and global authorities. Studies of biodiversity mainly involve traditional methods using morphological characters and molecular protocols. However, conventional methods are a time consuming and resource demanding task. The development of high-throughput sequencing (HTS) techniques has reshaped the way we explore biodiversity and opened a path to new questions and novel empirical approaches. With the emergence of HTS, sequencing the complete mitochondrial genome became more accessible, and the number of genome sequences published has increased exponentially during the last decades. Despite the current state of knowledge about the potential of mitogenomics in phylogenetics, this is still a relatively under-explored area for a multitude of taxonomic groups, especially for those without commercial relevance, non-models organisms and with preserved DNA. Here we take the first step to assemble and annotate the genomes from HTS data using a new protocol of genome skimming which will offer an opportunity to extend…

  66. 66
    top 3.2%

    Disentangling the effect of host-genotype and environment on the microbiome of the coral Acropora tenuis

    Bettina Glasl, Caitlin E. Smith, David G. Bourne, Nicole S. Webster

    92 citationsOpen access (CC-BY)doi:10.7717/peerj.6377OpenAlex

    Show abstract

    Genotype-specific contributions to the environmental tolerance and disease susceptibility of corals are widely accepted. Yet our understanding of how host genotype influences the composition and stability of the coral microbiome subjected to environmental fluctuations is limited. To gain insight into the community dynamics and environmental stability of microbiomes associated with distinct coral genotypes, we assessed the microbial community associated with Acropora tenuis under single and cumulative pressure experiments. Experimental treatments comprised either a single pulse of reduced salinity (minimum of 28 psu) or exposure to the cumulative pressures of reduced salinity (minimum of 28 psu), elevated seawater temperature (+2 °C), elevated p CO 2 (900 ppm), and the presence of macroalgae. Analysis of 16S rRNA gene amplicon sequence data revealed that A. tenuis microbiomes were highly host-genotype specific and maintained high compositional stability irrespective of experimental treatment. On average, 48% of the A. tenuis microbiome was dominated by Endozoicomonas. Amplicon…

  67. 67
    top 3.2%

    Phylogenomic analysis and revised classification of atypoid mygalomorph spiders (Araneae, Mygalomorphae), with notes on arachnid ultraconserved element loci

    Marshal C. Hedin, Shahan Derkarabetian, Adan Alfaro, Martín Javier Ramírez, Jason E. Bond

    91 citationsOpen access (CC-BY)doi:10.7717/peerj.6864OpenAlex

    Show abstract

    The atypoid mygalomorphs include spiders from three described families that build a diverse array of entrance web constructs, including funnel-and-sheet webs, purse webs, trapdoors, turrets and silken collars. Molecular phylogenetic analyses have generally supported the monophyly of Atypoidea, but prior studies have not sampled all relevant taxa. Here we generated a dataset of ultraconserved element loci for all described atypoid genera, including taxa ( Mecicobothrium and Hexurella) key to understanding familial monophyly, divergence times, and patterns of entrance web evolution. We show that the conserved regions of the arachnid UCE probe set target exons, such that it should be possible to combine UCE and transcriptome datasets in arachnids. We also show that different UCE probes sometimes target the same protein, and under the matching parameters used here show that UCE alignments sometimes include non-orthologs. Using multiple curated phylogenomic matrices we recover a monophyletic Atypoidea, and reveal that the family Mecicobothriidae comprises four separate and divergent…

  68. 68
    top 3.3%

    Fluoxetine-induced alteration of murine gut microbial community structure: evidence for a microbial endocrinology-based mechanism of action responsible for fluoxetine-induced side effects

    Mark Lyte, Karrie M. Daniels, Stephan Schmitz‐Esser

    91 citationsOpen access (CC-BY)doi:10.7717/peerj.6199OpenAlex

    Show abstract

    Background Depression and major depressive disorder affect 25% of the population. First line treatment utilizing selective serotonin reuptake inhibitors (SSRIs) have met with limited success due to well-recognized negative side effects which include weight gain or loss. This inability to control unwanted side effects often result in patients stopping their antidepressant medications. The mechanisms underlying the failure of SSRIs are incompletely understood. Methods Male CF-1 mice (5 weeks of age, N = 10 per group) were per orally administered fluoxetine (20 mg per kg body weight) or diluent daily for 29 days. During this time fecal specimens were collected at three defined time points (0, 15 and 29 days). At the conclusion of the 29-day dosing regimen, animals were subjected to two behavioral assessments. For bacterial identification of the microbiota, 16S rRNA gene sequencing was performed on 60 fecal specimens (three specimens per mouse time course, N = 20 mice) using Illumina MiSeq. Analysis of community sequence data was done using mothur and LEfSe bioinformatic software…

  69. 69
    top 3.3%

    Characterization and expression profiling of theICE-CBF-CORgenes in wheat

    Jie Guo, Yongkang Ren, Zhaohui Tang, Weiping Shi, Meixue Zhou

    90 citationsOpen access (CC-BY)doi:10.7717/peerj.8190OpenAlex

    Show abstract

    Cold stress is one of the major abiotic stresses that limit crop production. TheICE-CBF-CORpathway is associated with cold stress response in a wide variety of crop species. However, theICE-CBF-CORgenes has not been well characterized in wheat (Triticum aestivum). This study identified, characterized and examined the expression profiles of theICE, CBFandCORgenes for cold defense in wheat. FiveICE(inducer ofCBFexpression) genes, 37CBF(C-repeat binding factor) genes and 11COR(cold-responsive or cold-regulated) genes were discovered in the wheat genome database. Phylogenetic trees based on all 53 genes revealed thatCBFgenes were more diverse thanICEandCORgenes. Twenty-two of the 53 genes appeared to include 11 duplicated pairs. Twenty rice (Oryza sativa) genes and 21 sorghum (Sorghum bicolor) and maize (Zea mays) genes showed collinearity with the wheatICE,CBFandCORgenes. Transcriptome data and qRT-PCR analyses revealed tissue-specific expression patterns of theICE,CBFandCORgenes, and identified similarities in the expression pattern of genes from the same family when subjected to…

  70. 70
    top 3.3%

    Bacterial microbiota composition of Ixodes ricinus ticks: the role of environmental variation, tick characteristics and microbial interactions

    Tuomas Aivelo, Anna Norberg, Barbara Tschirren

    89 citationsOpen access (CC-BY)doi:10.7717/peerj.8217OpenAlex

    Show abstract

    Abstract The factors shaping microbial communities within organisms are still poorly understood. Besides ecological factors and host characteristics, direct interactions among microbes may shape the occurrence of microbes and the structure of communities. In the past it has been difficult to disentangle if patterns of microbial co-occurrence are due to facilitation or competition effects, or shaped by shared ecological preferences (i.e., environmental filtering). Here we use a joint species distribution model to characterize the bacterial microbiota composition of an important human disease vector, the sheep tick Ixodes ricinus , along ecological gradients in the Swiss Alps, and to test for facilitation or competition effects among human pathogens and tick endosymbionts. We identify a number of ecological variables that significantly predicted the diversity of tick microbial community and the occurrence of specific tick endosymbionts and human pathogens. However, ecological associations were generally microbe-specific rather than universal. We also found evidence for significant…

  71. 71
    top 3.4%

    Chronic trace metals effects of mine tailings on estuarine assemblages revealed by environmental DNA

    Angelo Fraga Bernardino, Fabiano Sviatopolk-Mirsky Pais, Louisi Souza de Oliveira, Fabrício Ãngelo Gabriel, Tiago Osório Ferreira and 2 more

    89 citationsOpen access (CC-BY)doi:10.7717/peerj.8042OpenAlex

    Show abstract

    Mine tailing disasters have occurred worldwide and contemporary release of tailings of large proportions raise concerns of the chronic impacts that trace metals may have on the aquatic biodiversity. Environmental metabarcoding (eDNA) offers an as yet poorly explored opportunity for biological monitoring of impacted aquatic ecosystems from mine tailings and contaminated sediments. eDNA has been increasingly recognized to be an effective method to detect previously unrecognized small-sized Metazoan taxa, but their ecological responses to environmental pollution has not been assessed by metabarcoding. Here, we evaluated chronic effects of trace metal contamination from sediment eDNA of the Rio Doce estuary, 1.7 years after the Samarco mine tailing disaster, which released over 40 million m 3 of iron tailings in the Rio Doce river basin. We identified 123 new sequence variants environmental taxonomic units (eOTUs) of benthic taxa and an assemblage composition dominated by Nematoda, Crustacea and Platyhelminthes; typical of other estuarine ecosystems. We detected environmental filtering…

  72. 72
    top 3.4%

    Roles of phytohormone changes in the grain yield of rice plants exposed to heat: a review

    Chao Wu, She Tang, Ganghua Li, Shao‐Hua Wang, Shah Fahad and 1 more

    88 citationsOpen access (CC-BY)doi:10.7717/peerj.7792OpenAlex

    Show abstract

    During its reproductive phase, rice is susceptible to heat stress. Heat events will occur at all stages during the reproductive phase of rice as a result of global warming. Moreover, rice yield traits respond differently to heat stress during panicle initiation, flowering and grain filling. The reduction in the number of spikelets per panicle of heat-stressed plants is due to the attenuated differentiation of secondary branches and their attached florets as well as the promotion of their degradation during the panicle-initiation stage but is not affected by heat stress thereafter. Spikelet sterility as a result of heat stress is attributed not only to physiological abnormalities in the reproductive organs during the flowering stage but also to structural and morphological abnormalities in reproductive organs during the panicle-initiation stage. The reduced grain weight of heat-stressed plants is due to a reduction in nonstructural carbohydrates, undeveloped vascular bundles, and a reduction in glume size during the panicle-initiation stage, while a shortened grain-filling duration,…

  73. 73
    top 3.5%

    The gut microbiome correlates with conspecific aggression in a small population of rescued dogs(Canis familiaris)

    Nicole S. Kirchoff, Monique A. R. Udell, Thomas J. Sharpton

    88 citationsOpen access (CC-BY)doi:10.7717/peerj.6103OpenAlex

    Show abstract

    Aggression is a serious behavioral disorder in domestic dogs that endangers both dogs and humans. The underlying causes of canine aggression are poorly resolved and require illumination to ensure effective therapy. Recent research links the compositional diversity of the gut microbiome to behavioral and psychological regulation in other mammals, such as mice and humans. Given these observations, we hypothesized that the composition of the canine gut microbiome could associate with aggression. We analyzed fecal microbiome samples collected from a small population of pit bull type dogs seized from a dogfighting organization. This population included 21 dogs that displayed conspecific aggressive behaviors and 10 that did not. Beta-diversity analyses support an association between gut microbiome structure and dog aggression. Additionally, we used a phylogenetic approach to resolve specific clades of gut bacteria that stratify aggressive and non-aggressive dogs, including clades withinLactobacillus,Dorea,Blautia,Turicibacter,andBacteroides. Several of these taxa have been implicated in…

  74. 74
    top 3.5%

    A comprehensive molecular phylogeny of Geometridae (Lepidoptera) with a focus on enigmatic small subfamilies

    Leidys Murillo‐Ramos, Gunnar Brehm, Pasi Sihvonen, Axel Hausmann, Sille Holm and 7 more

    86 citationsOpen access (CC-BY)doi:10.7717/peerj.7386OpenAlex

    Show abstract

    Our study aims to investigate the relationships of the major lineages within the moth family Geometridae, with a focus on the poorly studied Oenochrominae-Desmobathrinae complex, and to translate some of the results into a coherent subfamilial and tribal level classification for the family. We analyzed a molecular dataset of 1,206 Geometroidea terminal taxa from all biogeographical regions comprising up to 11 molecular markers that includes one mitochondrial (COI) and 10 protein-coding nuclear gene regions (wingless, ArgK, MDH, RpS5, GAPDH, IDH, Ca-ATPase, Nex9, EF-1alpha, CAD). The molecular data set was analyzed using maximum likelihood as implemented in IQ-TREE and RAxML. We found high support for the subfamilies Larentiinae, Geometrinae and Ennominae in their traditional scopes. Sterrhinae becomes monophyletic only if Ergavia Walker, Ametris Hübner and Macrotes Westwood, which are currently placed in Oenochrominae, are formally transferred to Sterrhinae. Desmobathrinae and Oenochrominae are found to be polyphyletic. The concepts of Oenochrominae and Desmobathrinae required major…

  75. 75
    top 3.6%

    A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight

    Scott A. Hartman, Mickey Mortimer, William Wahl, Dean R. Lomax, Jessica L. Lippincott and 1 more

    86 citationsOpen access (CC-BY)doi:10.7717/peerj.7247OpenAlex

    Show abstract

    The last two decades have seen a remarkable increase in the known diversity of basal avialans and their paravian relatives. The lack of resolution in the relationships of these groups combined with attributing the behavior of specialized taxa to the base of Paraves has clouded interpretations of the origin of avialan flight. Here, we describe Hesperornithoides miessleri gen. et sp. nov., a new paravian theropod from the Morrison Formation (Late Jurassic) of Wyoming, USA, represented by a single adult or subadult specimen comprising a partial, well-preserved skull and postcranial skeleton. Limb proportions firmly establish Hesperornithoides as occupying a terrestrial, non-volant lifestyle. Our phylogenetic analysis emphasizes extensive taxonomic sampling and robust character construction, recovering the new taxon most parsimoniously as a troodontid close to Daliansaurus , Xixiasaurus , and Sinusonasus . Multiple alternative paravian topologies have similar degrees of support, but proposals of basal paravian archaeopterygids, avialan microraptorians, and Rahonavis being closer to…

  76. 76
    top 3.6%

    Cortical modulation of pupillary function: systematic review

    Costanza Peinkhofer, Gitte M. Knudsen, Rita Moretti, Daniel Kondziella

    84 citationsOpen access (CC-BY)doi:10.7717/peerj.6882OpenAlex

    Show abstract

    BACKGROUND: The pupillary light reflex is the main mechanism that regulates the pupillary diameter; it is controlled by the autonomic system and mediated by subcortical pathways. In addition, cognitive and emotional processes influence pupillary function due to input from cortical innervation, but the exact circuits remain poorly understood. We performed a systematic review to evaluate the mechanisms behind pupillary changes associated with cognitive efforts and processing of emotions and to investigate the cerebral areas involved in cortical modulation of the pupillary light reflex. METHODOLOGY: We searched multiple databases until November 2018 for studies on cortical modulation of pupillary function in humans and non-human primates. Of 8,809 papers screened, 258 studies were included. RESULTS: Most investigators focused on pupillary dilatation and/or constriction as an index of cognitive and emotional processing, evaluating how changes in pupillary diameter reflect levels of attention and arousal. Only few tried to correlate specific cerebral areas to pupillary changes, using…

  77. 77
    top 3.7%

    Mahalanobis distances and ecological niche modelling: correcting a chi-squared probability error

    Thomas R. Etherington

    83 citationsOpen access (CC-BY)doi:10.7717/peerj.6678OpenAlex

    Show abstract

    The Mahalanobis distance is a statistical technique that can be used to measure how distant a point is from the centre of a multivariate normal distribution. By measuring Mahalanobis distances in environmental space ecologists have also used the technique to model: ecological niches, habitat suitability, species distributions, and resource selection functions. Unfortunately, the original description of the Mahalanobis distance technique for ecological modelling contained an error describing how Mahalanobis distances could be converted into probabilities using a chi-squared distribution. This error has been repeated in the literature, and is present in popular modelling software. In the hope of correcting this error to maximise the potential application of the Mahalanobis distance technique within the ecological modelling community, I explain how Mahalanobis distances are calculated, and through a virtual ecology experiment demonstrate how to correctly produce probabilities and discuss the implications of the error for previous Mahalanobis distance studies.

  78. 78
    top 3.7%

    The Koala ( Phascolarctos cinereus ) faecal microbiome differs with diet in a wild population

    Kylie L. Brice, Pankaj Trivedi, Thomas C. Jeffries, Michaela D. J. Blyton, Christopher Mitchell and 2 more

    83 citationsOpen access (CC-BY)doi:10.7717/peerj.6534OpenAlex

    Show abstract

    Background The diet of the koala ( Phascolarctos cinereus ) is comprised almost exclusively of foliage from the genus Eucalyptus (family Myrtaceae). Eucalyptus produces a wide variety of potentially toxic plant secondary metabolites which have evolved as chemical defences against herbivory. The koala is classified as an obligate dietary specialist, and although dietary specialisation is rare in mammalian herbivores, it has been found elsewhere to promote a highly-conserved but low-diversity gut microbiome. The gut microbes of dietary specialists have been found sometimes to enhance tolerance of dietary PSMs, facilitating competition-free access to food. Although the koala and its gut microbes have evolved together to utilise a low nutrient, potentially toxic diet, their gut microbiome has not previously been assessed in conjunction with diet quality. Thus, linking the two may provide new insights in to the ability of the koala to extract nutrients and detoxify their potentially toxic diet. Method The 16S rRNA gene was used to characterise the composition and diversity of faecal…

  79. 79
    top 3.8%

    Common garden comparisons confirm inherited differences in sensitivity to climate change between forest tree species

    Cuauhtémoc Sáenz‐Romero, Antoine Kremer, László Nagy, Éva Újvári-Jármay, Alexis Ducousso and 3 more

    81 citationsOpen access (CC-BY)doi:10.7717/peerj.6213OpenAlex

    Show abstract

    The natural distribution, habitat, growth and evolutionary history of tree species are strongly dependent on ecological and genetic processes in ecosystems subject to fluctuating climatic conditions, but there have been few experimental comparisons of sensitivity between species. We compared the responses of two broadleaved tree species ( Fagus sylvatica and Quercus petraea ) and two conifer tree species ( Pinus sylvestris and Picea abies ) to climatic transfers by fitting models containing the same climatic variables. We used published data from European provenance test networks to model the responses of individual populations nested within species. A mixed model approach was applied to develop a response function for tree height over climatic transfer distance, taking into account the climatic conditions at both the seed source and the test location. The two broadleaved species had flat climatic response curves, indicating high levels of plasticity in populations, facilitating adaptation to a broader range of environments, and conferring a high potential for resilience in the face…

  80. 80
    top 3.8%

    Individual tree crown delineation and tree species classification with hyperspectral and LiDAR data

    Michele Dalponte, Lorenzo Frizzera, Damiano Gianelle

    80 citationsOpen access (CC-BY)doi:10.7717/peerj.6227OpenAlex

    Show abstract

    An international data science challenge, called National Ecological Observatory Network-National Institute of Standards and Technology data science evaluation, was set up in autumn 2017 with the goal to improve the use of remote sensing data in ecological applications. The competition was divided into three tasks: (1) individual tree crown (ITC) delineation, for identifying the location and size of individual trees; (2) alignment between field surveyed trees and ITCs delineated on remote sensing data; and (3) tree species classification. In this paper, the methods and results of team Fondazione Edmund Mach (FEM) are presented. The ITC delineation (Task 1 of the challenge) was done using a region growing method applied to a near-infrared band of the hyperspectral images. The optimization of the parameters of the delineation algorithm was done in a supervised way on the basis of the Jaccard score using the training set provided by the organizers. The alignment (Task 2) between the delineated ITCs and the field surveyed trees was done using the Euclidean distance among the position,…

  81. 81
    top 3.9%

    Identification of prognostic gene signature associated with microenvironment of lung adenocarcinoma

    Cheng Yue, Hongtao Ma, Yubai Zhou

    79 citationsOpen access (CC-BY)doi:10.7717/peerj.8128OpenAlex

    Show abstract

    BACKGROUND: Lung cancer has the highest morbidity and mortality worldwide, and lung adenocarcinoma (LADC) is the most common pathological subtype. Accumulating evidence suggests the tumor microenvironment (TME) is correlated with the tumor progress and the patient's outcome. As the major components of TME, the tumor-infiltrated immune cells and stromal cells have attracted more and more attention. In this study, differentially expressed immune and stromal signature genes were used to construct a TME-related prognostic model for predicting the outcomes of LADC patients. METHODS: The expression profiles of LADC samples with clinical information were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). The differentially expressed genes (DEGs) related to the TME of LADC were identified using TCGA dataset by Wilcoxon rank sum test. The prognostic effects of TME-related DEGs were analyzed using univariate Cox regression. Then, the least absolute shrinkage and selection operator (LASSO) regression was performed to reduce the overfit and the number of genes for…

  82. 82
    top 3.9%

    Potential ecotoxicological effects of antimicrobial surface coatings: a literature survey backed up by analysis of market reports

    Merilin Rosenberg, Krunoslav Ilić, Katre Juganson, Angela Ivask, Merja H. Ahonen and 2 more

    79 citationsOpen access (CC-BY)doi:10.7717/peerj.6315OpenAlex

    Show abstract

    This review was initiated by the COST action CA15114 AMICI "Anti-Microbial Coating Innovations to prevent infectious diseases," where one important aspect is to analyze ecotoxicological impacts of antimicrobial coatings (AMCs) to ensure their sustainable use. Scopus database was used to collect scientific literature on the types and uses of AMCs, while market reports were used to collect data on production volumes. Special attention was paid on data obtained for the release of the most prevalent ingredients of AMCs into the aqueous phase that was used as the proxy for their possible ecotoxicological effects. Based on the critical analysis of 2,720 papers, it can be concluded that silver-based AMCs are by far the most studied and used coatings followed by those based on titanium, copper, zinc, chitosan and quaternary ammonium compounds. The literature analysis pointed to biomedicine, followed by marine industry, construction industry (paints), food industry and textiles as the main fields of application of AMCs. The published data on ecotoxicological effects of AMCs was scarce, and…

  83. 83
    top 4%

    Effects of ferulic acid esterase-producing Lactobacillus fermentum and cellulase additives on the fermentation quality and microbial community of alfalfa silage

    Rina Su, Kuikui Ni, Tianwei Wang, Xiaopan Yang, Jie Zhang and 5 more

    78 citationsOpen access (CC-BY)doi:10.7717/peerj.7712OpenAlex

    Show abstract

    Background Alfalfa ( Medicago sativa ) is an important forage material widely used for animal feed production. Ensiling is an effective method for preserving alfalfa, but it has shown some limitations in the production of high-quality alfalfa silage due to its low water soluble carbohydrates (WSC) content and high buffering capacity. Lactic acid bacteria (LAB) and cellulase are often used as silage additives to promote the ensiling process and enhance fermentation quality. Methods Experiments were conducted to investigate the effects of ferulic acid esterase (FAE)-producing Lactobacillus fermentum 17SD-2 (LF) and cellulase (CE) on the fermentation quality and microbial community of alfalfa silage. After 60 days of ensiling, analysis of fermentation quality and bacterial diversity in alfalfa silages were conducted using high-performance liquid chromatography and high-throughput sequencing methods. Results Alfalfa was ensiled with additives (LF, CE, and LF+CE) or without additives for 60 days. All additives increased lactic acid and decreased pH values and ammonia-N contents compared…

  84. 84
    top 4%

    Soil bacterial biodiversity is driven by long-term pasture management, poultry litter, and cattle manure inputs

    Yichao Yang, Amanda Joy Ashworth, Jennifer M. DeBruyn, Cammy D. Willett, Lisa M. Durso and 3 more

    78 citationsOpen access (PUBLIC-DOMAIN)doi:10.7717/peerj.7839OpenAlex

    Show abstract

    Soil microorganisms are important for maintaining soil health, decomposing organic matter, and recycling nutrients in pasture systems. However, the impact of long-term conservation pasture management on soil microbial communities remains unclear. Therefore, soil microbiome responses to conservation pasture management is an important component of soil health, especially in the largest agricultural land-use in the US. The aim of this study was to identify soil microbiome community differences following 13-years of pasture management (hayed (no cattle), continuously grazed, rotationally grazed with a fenced, un-grazed and unfertilized buffer strip, and a control (no poultry litter or cattle manure inputs)). Since 2004, all pastures (excluding the control) received annual poultry litter at a rate of 5.6 Mg ha −1 . Soil samples were collected at a 0–15 cm depth from 2016–2017 either pre or post poultry litter applications, and bacterial communities were characterized using Illumina 16S rRNA gene amplicon sequencing. Overall, pasture management influenced soil microbial community…

  85. 85
    top 4.1%

    Exploring wearable sensors as an alternative to marker-based motion capture in the pitching delivery

    Kyle J. Boddy, Joseph A. Marsh, Alex Caravan, Kyle E. Lindley, John O'Bryan Scheffey and 1 more

    78 citationsOpen access (CC-BY)doi:10.7717/peerj.6365OpenAlex

    Show abstract

    BACKGROUND: Improvements in data processing, increased understanding of the biomechanical background behind kinetics and kinematics, and technological advancements in inertial measurement unit (IMU) sensors have enabled high precision in the measurement of joint angles and acceleration on human subjects. This has resulted in new devices that reportedly measure joint angles, arm speed, and stresses to the pitching arms of baseball players. This study seeks to validate one such sensor, the MotusBASEBALL unit, with a marker-based motion capture laboratory. HYPOTHESIS: We hypothesize that the joint angle measurements ("arm slot" and "shoulder rotation") of the MotusBASEBALL device will hold a statistically significant level of reliability and accuracy, but that the "arm speed" and "stress" metrics will not be accurate due to limitations in IMU technology. METHODS: A total of 10 healthy subjects threw five to seven fastballs followed by five to seven breaking pitches (slider or curveball) in the motion capture lab. Subjects wore retroreflective markers and the MotusBASEBALL sensor…

  86. 86
    top 4.1%

    Intestinal parasitic infection alters bacterial gut microbiota in children

    Miguel Toro-Londoño, Katherine Bedoya-Urrego, Gisela García-Montoya, Ana Luz Galván-Díaz, Juan F. Álzate

    78 citationsOpen access (CC-BY)doi:10.7717/peerj.6200OpenAlex

    Show abstract

    The study of the burden that parasites can exert upon the bacterial gut microbiota was restricted by the available technologies and their costs. Currently, next-generation sequencing coupled with traditional methodologies allows the study of eukaryotic parasites (protozoa and helminths) and its effects on the human bacterial gut microbiota diversity. This diversity can be altered by a variety of factors such as age, diet, genetics and parasitic infections among others. The disturbances of the gut microbiota have been associated with a variety of illnesses. Children population in developing countries, are especially susceptible to parasitic infections because of the lack of proper sanitation and undernutrition, allowing both, the thriving of intestinal parasites and profound alteration of the gut microbiota. In this work, we have sampled the stool of 23 children from four different children’s care-centers in Medellin, Colombia, and we have identified the eukaryotic parasites by traditional and molecular methodologies coupled with microbial profiling using 16S rDNA sequencing. This…

  87. 87
    top 4.1%

    PGM5: a novel diagnostic and prognostic biomarker for liver cancer

    Yan Jiao, Yanqing Li, Peiqiang Jiang, Wei Han, Yahui Liu

    77 citationsOpen access (CC-BY)doi:10.7717/peerj.7070OpenAlex

    Show abstract

    Background Liver cancer is a common malignancy and a significant public health problem worldwide, but diagnosis and prognostic evaluation remain challenging for clinicians. Metabolic reprogramming is a hallmark of cancer, and we therefore examined the diagnostic and prognostic value of a metabolic enzyme, phosphoglucomutase-like protein 5 (PGM5), in liver cancer. Methods All data were from The Cancer Genome Atlas database. R and related statistical packages were used for data analysis. HepaticPGM5expression was determined in different groups, and the chi-squared test and Fisher’s exact test were used to determine the significance of differences. The pROC package was used to determine receiver operating characteristic (ROC) curves, the survival package was used to for survival analysis and development of a Cox multivariable model, and the ggplot2 package was used for data visualization. Results PGM5expression was significantly lower in cancerous than adjacent normal liver tissues, and had modest diagnostic value based on ROC analysis and calculations of area under the curve (AUC).…

  88. 88
    top 4.2%

    Evaluating the effects of a temporary fostering program on shelter dog welfare

    Lisa M. Gunter, Erica N. Feuerbacher, Rachel J. Gilchrist, Clive D. L. Wynne

    77 citationsOpen access (CC-BY)doi:10.7717/peerj.6620OpenAlex

    Show abstract

    One of the greatest stressors for dogs living in animal shelters is social isolation. Many studies have demonstrated that human interaction reduces cortisol in shelter dogs, with the possibility that longer periods of interaction may yield greater effects. These types of interventions are contingent upon removing the dog from the kennel and any such reductions in cortisol are often lost when the dog returns to the kennel. More recently, animal shelters are utilizing short-term fostering programs to provide relief from the perceived stresses of kennel life; however the effects of these programs are not well understood. This study assessed the impacts of one- and two-night fostering programs on the urinary cortisol levels, resting pulse rates, longest bout of uninterrupted rest, and proportion of time spent resting of dogs awaiting adoption. Five animal shelters, open and limited-admission facilities, from across the United States participated in the study. During the study, dogs' urine was collected in the morning before, during, and after fostering stays for cortisol: creatinine…

  89. 89
    top 4.2%

    Application of open field, tonic immobility, and attention bias tests to hens with different ranging patterns

    Dana L. M. Campbell, Emily J. Dickson, Caroline Lee

    76 citationsOpen access (CC-BY)doi:10.7717/peerj.8122OpenAlex

    Show abstract

    Assessment of negative affective states is a key component of animal welfare research. In laying hens, excessive fearfulness results in reduced production and increased sensitivity to stress. Fearfulness can be defined as a response to a known threat, but anxiety is a response to an unknown threat and may have similar negative consequences. The open field test and tonic immobility test are commonly applied to measure fearfulness in laying hens. An attention bias test that measured individual hen’s responses to playback of a conspecific alarm call in the presence of food was recently pharmacologically validated using an anxiogenic drug but was confounded by the hen’s typical motionless response in a novel environment. The current study used 56-week old free-range layers to further assess the validity of an attention bias test to differentiate ranging treatment groups in comparison with the open field and tonic immobility tests. The selected hens varied in their range use patterns as tracked by radio-frequency identification technology. ‘Indoor’ hens did not access the range and…

  90. 90
    top 4.3%

    Microbial communities associated with the black morel Morchella sextelata cultivated in greenhouses

    Gian Maria Niccolò Benucci, Reid Longley, Peng Zhang, Qi Zhao, Gregory M Bonito and 1 more

    76 citationsOpen access (CC-BY)doi:10.7717/peerj.7744OpenAlex

    Show abstract

    Morels ( Morchella spp.) are iconic edible mushrooms with a long history of human consumption. Some microbial taxa are hypothesized to be important in triggering the formation of morel primordia and development of fruiting bodies, thus, there is interest in the microbial ecology of these fungi. To identify and compare fungal and prokaryotic communities in soils where Morchella sextelata is cultivated in outdoor greenhouses, ITS and 16S rDNA high throughput amplicon sequencing and microbiome analyses were performed. Pedobacter , Pseudomonas , Stenotrophomonas , and Flavobacterium were found to comprise the core microbiome of M. sextelata ascocarps. These bacterial taxa were also abundant in the soil beneath growing fruiting bodies. A total of 29 bacterial taxa were found to be statistically associated to Morchella fruiting bodies. Bacterial community network analysis revealed high modularity with some 16S rDNA operational taxonomic unit clusters living in specialized fungal niches (e.g., pileus, stipe). Other fungi dominating the soil mycobiome beneath morels included Morchella ,…

  91. 91
    top 4.3%

    The RIPper, a web-based tool for genome-wide quantification of Repeat-Induced Point (RIP) mutations

    Stephanie van Wyk, Christopher H. Harrison, Brenda Diana Wingfield, Lieschen De Vos, Nicolaas A. van der Merwe and 1 more

    76 citationsOpen access (CC-BY)doi:10.7717/peerj.7447OpenAlex

    Show abstract

    Background The RIPper ( http://theripper.hawk.rocks ) is a set of web-based tools designed for analyses of Repeat-Induced Point (RIP) mutations in the genome sequences of Ascomycota. The RIP pathway is a fungal genome defense mechanism that is aimed at identifying repeated and duplicated motifs, into which it then introduces cytosine to thymine transition mutations. RIP thus serves to deactivate and counteract the deleterious consequences of selfish or mobile DNA elements in fungal genomes. The occurrence, genetic context and frequency of RIP mutations are widely used to assess the activity of this pathway in genomic regions of interest. Here, we present a bioinformatics tool that is specifically fashioned to automate the investigation of changes in RIP product and substrate nucleotide frequencies in fungal genomes. Results We demonstrated the ability of The RIPper to detect the occurrence and extent of RIP mutations in known RIP affected sequences. Specifically, a sliding window approach was used to perform genome-wide RIP analysis on the genome assembly of Neurospora crassa .…

  92. 92
    top 4.4%

    Symmetry preference in shapes, faces, flowers and landscapes

    Marco Bertamini, Giulia Rampone, Alexis D. J. Makin, Andrew Jessop

    75 citationsOpen access (CC-BY)doi:10.7717/peerj.7078OpenAlex

    Show abstract

    Most people like symmetry, and symmetry has been extensively used in visual art and architecture. In this study, we compared preference for images of abstract and familiar objects in the original format or when containing perfect bilateral symmetry. We created pairs of images for different categories: male faces, female faces, polygons, smoothed version of the polygons, flowers, and landscapes. This design allows us to compare symmetry preference in different domains. Each observer saw all categories randomly interleaved but saw only one of the two images in a pair. After recording preference, we recorded a rating of how salient the symmetry was for each image, and measured how quickly observers could decide which of the two images in a pair was symmetrical. Results reveal a general preference for symmetry in the case of shapes and faces. For landscapes, natural (no perfect symmetry) images were preferred. Correlations with judgments of saliency were present but generally low, and for landscapes the salience of symmetry was negatively related to preference. However, even within the…

  93. 93
    top 4.4%

    Anatomy of Rhinochelys pulchriceps (Protostegidae) and marine adaptation during the early evolution of chelonioids

    Serjoscha Evers, Paul M. Barrett, Roger Benson

    75 citationsOpen access (CC-BY)doi:10.7717/peerj.6811OpenAlex

    Show abstract

    Knowledge of the early evolution of sea turtles (Chelonioidea) has been limited by conflicting phylogenetic hypotheses resulting from sparse taxon sampling and a superficial understanding of the morphology of key taxa. This limits our understanding of evolutionary adaptation to marine life in turtles, and in amniotes more broadly. One problematic group are the protostegids, Early–Late Cretaceous marine turtles that have been hypothesised to be either stem-cryptodires, stem-chelonioids, or crown-chelonioids. Different phylogenetic hypotheses for protostegids suggest different answers to key questions, including (1) the number of transitions to marine life in turtles, (2) the age of the chelonioid crown-group, and (3) patterns of skeletal evolution during marine adaptation. We present a detailed anatomical study of one of the earliest protostegids, Rhinochelys pulchriceps from the early Late Cretaceous of Europe, using high-resolution μCT. We synonymise all previously named European species and document the variation seen among them. A phylogeny of turtles with increased chelonioid…

  94. 94
    top 4.5%

    Synthesis of silver nanoparticles using a modified Tollens’ method in conjunction with phytochemicals and assessment of their antimicrobial activity

    Muna Abu‐Dalo, Ismaeel R. Al-Mheidat, Alham W. Al-Shurafat, Colleen Grinham, Vinka A. Oyanedel-Craver

    75 citationsOpen access (CC-BY)doi:10.7717/peerj.6413OpenAlex

    Show abstract

    Background Silver nanoparticles (AgNPs) have attracted great attention due to their outstanding electrical, optical, magnetic, catalytic, and antimicrobial properties. However, there is a need for alternative production methods that use less toxic precursors and reduce their undesirable by-products. Phyto-extracts from the leaves of olive and rosemary plants can be used as reducing agents and (in conjunction with Tollens’ reagent) can even enhance AgNP antimicrobial activity. Methods Conditions for the proposed hybrid synthesis method were optimized for olive leaf extracts (OLEs) and rosemary leaf extracts (RLEs). The resultant AgNPs were characterized using UV–visible spectroscopy, an environmental scanning electron microscope, and Dynamic Light Scattering analysis. An atomic absorption spectrophotometer was used to measure AgNP concentration. Fourier transform infrared spectroscopy (FTIR) was used to determine the specific functional groups responsible for the reduction of both silver nitrate and capping agents in the leaf extract. Additionally, the antimicrobial properties of the…

  95. 95
    top 4.5%

    Promotion of growth and metal accumulation of alfalfa by coinoculation with Sinorhizobium and Agrobacterium under copper and zinc stress

    Liru Jian, Xiaoli Bai, Hui Zhang, Xiuyong Song, Zhefei Li

    74 citationsOpen access (CC-BY)doi:10.7717/peerj.6875OpenAlex

    Show abstract

    The Legume-Rhizobium symbiosis has been proposed as a promising technique for the phytoremediation of contaminated soils due to its beneficial activity in symbiotic nitrogen fixation. However, numerous studies have shown that excessive heavy metals reduce the efficiency of symbiotic nodulation with Rhizobium and inhibit plant growth. In this study, we aimed to evaluate the synergistic effects of IAA-producing bacteria and Rhizobium on Medicago lupulina growth under Cu and Zn stress. Pot experiments showed that 400 mg kg −1 Cu 2 + and Zn 2 + greatly inhibited plant growth, but dual inoculation of Medicago lupulina with Sinorhizobium meliloti CCNWSX0020 and Agrobacterium tumefaciens CCNWGS0286 significantly increased the number of nodules and plant biomass by enhancing antioxidant activities. Under double stress of 400 mg kg −1 Cu 2 + and Zn 2 + , the nodule number and nitrogenase activities of dual-inoculated plants were 48.5% and 154.4% higher, respectively, than those of plants inoculated with Sinorhizobium meliloti . The root and above-ground portion lengths of the dual-inoculated…

  96. 96
    top 4.6%

    An interpretable machine learning model for diagnosis of Alzheimer's disease

    Diptesh Das, Junichi Ito, Tadashi Kadowaki, Koji Tsuda

    74 citationsOpen access (CC-BY)doi:10.7717/peerj.6543OpenAlex

    Show abstract

    We present an interpretable machine learning model for medical diagnosis called sparse high-order interaction model with rejection option (SHIMR). A decision tree explains to a patient the diagnosis with a long rule (i.e., conjunction of many intervals), while SHIMR employs a weighted sum of short rules. Using proteomics data of 151 subjects in the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset, SHIMR is shown to be as accurate as other non-interpretable methods (Sensitivity, SN = 0.84 ± 0.1, Specificity, SP = 0.69 ± 0.15 and Area Under the Curve, AUC = 0.86 ± 0.09). For clinical usage, SHIMR has a function to abstain from making any diagnosis when it is not confident enough, so that a medical doctor can choose more accurate but invasive and/or more costly pathologies. The incorporation of a rejection option complements SHIMR in designing a multistage cost-effective diagnosis framework. Using a baseline concentration of cerebrospinal fluid (CSF) and plasma proteins from a common cohort of 141 subjects, SHIMR is shown to be effective in designing a patient-specific…

  97. 97
    top 4.6%

    Diverse and variable virus communities in wild plant populations revealed by metagenomic tools

    Hanna Susi, Denis Filloux, Mikko J. Frilander, Philippe Roumagnac, Anna‐Liisa Laine

    74 citationsOpen access (CC-BY)doi:10.7717/peerj.6140OpenAlex

    Show abstract

    Wild plant populations may harbour a myriad of unknown viruses. As the majority of research efforts have targeted economically important plant species, the diversity and prevalence of viruses in the wild has remained largely unknown. However, the recent shift towards metagenomics-based sequencing methodologies, especially those targeting small RNAs, is finally enabling virus discovery from wild hosts. Understanding this diversity of potentially pathogenic microbes in the wild can offer insights into the components of natural biodiversity that promotes long-term coexistence between hosts and parasites in nature, and help predict when and where risks of disease emergence are highest. Here, we used small RNA deep sequencing to identify viruses inPlantago lanceolatapopulations, and to understand the variation in their prevalence and distribution across the Åland Islands, South-West Finland. By subsequent design of PCR primers, we screened the five most common viruses from two sets ofP. lanceolataplants: 164 plants collected from 12 populations irrespective of symptoms, and 90 plants…

  98. 98
    top 4.7%

    Effects of salinity on photosynthetic traits, ion homeostasis and nitrogen metabolism in wild and cultivated soybean

    Abd Ullah, Mingxia Li, Javaria Noor, Akash Tariq, Yuan Liu and 1 more

    73 citationsOpen access (CC-BY)doi:10.7717/peerj.8191OpenAlex

    Show abstract

    Background Carbon and nitrogen metabolism need to be highly regulated to achieve cell acclimation to changing environmental conditions. The understanding of physio-biochemical responses of crops to salinity stress could help to stabilize their performance and yield. In this study we have analyzed the roles of photosynthesis, ion physiology and nitrate assimilation toward saline/alkaline stress acclimation in wild and cultivated soybean seedlings. Methods Growth and photosynthetic parameters, ion concentrations and the activity of enzymes involved in nitrogen assimilation were determined in seedlings of one wild and one cultivated soybean accession subjected to saline or alkaline stresses. Results Both saline and alkaline stresses had a negative impact on the growth and metabolism of both wild and cultivated soybean.The growth, photosynthesis, and gas exchange parameters showed a significant decrease in response to increasing salt concentration. Additionally, a significant increase in root Na + and Cl – concentration was observed. However, photosynthetic performance and ion…

  99. 99
    top 4.7%

    Towards optimized viral metagenomes for double-stranded and single-stranded DNA viruses from challenging soils

    Gareth Trubl, Simon Roux, Natalie Solonenko, Yueh-Fen Li, Benjamin Bolduc and 4 more

    73 citationsOpen access (CC-BY)doi:10.7717/peerj.7265OpenAlex

    Show abstract

    Soils impact global carbon cycling and their resident microbes are critical to their biogeochemical processing and ecosystem outputs. Based on studies in marine systems, viruses infecting soil microbes likely modulate host activities via mortality, horizontal gene transfer, and metabolic control. However, their roles remain largely unexplored due to technical challenges with separating, isolating, and extracting DNA from viruses in soils. Some of these challenges have been overcome by using whole genome amplification methods and while these have allowed insights into the identities of soil viruses and their genomes, their inherit biases have prevented meaningful ecological interpretations. Here we experimentally optimized steps for generating quantitatively-amplified viral metagenomes to better capture both ssDNA and dsDNA viruses across three distinct soil habitats along a permafrost thaw gradient. First, we assessed differing DNA extraction methods (PowerSoil, Wizard mini columns, and cetyl trimethylammonium bromide) for quantity and quality of viral DNA. This established…

  100. 100
    top 4.8%

    Dietary supplementation with probiotics regulates gut microbiota structure and function in Nile tilapia exposed to aluminum

    Leilei Yu, Nanzhen Qiao, Tianqi Li, Ruipeng Yu, Qixiao Zhai and 4 more

    73 citationsOpen access (CC-BY)doi:10.7717/peerj.6963OpenAlex

    Show abstract

    Backgrounds and aims Aluminum contamination of water is becoming increasingly serious and threatens the health status of fish. Lactobacillus plantarum CCFM639 was previously shown to be a potential probiotic for alleviation aluminum toxicity in Nile tilapia. Considering the significant role of the gut microbiota on fish health, it seems appropriate to explore the relationships among aluminum exposure, probiotic supplementation, and the gut microbiota in Nile tilapia and to determine whether regulation of the gut microbiota is related to alleviation of aluminum toxicity by a probiotic in Nile tilapia. Methods and results The tilapia were assigned into four groups, control, CCFM639 only, aluminum only, and aluminum + CCFM639 groups for an experimental period of 4 weeks. The tilapia in the aluminum only group were grown in water with an aluminum ion concentration of 2.73 mg/L. The final concentration of CCFM639 in the diet was 10 8 CFU/g. The results show that environmental aluminum exposure reduced the numbers of L. plantarum in tilapia feces and altered the gut microbiota. As the…

How to read this list

The cohort is every article, review and book chapter OpenAlex attributes to PeerJ with publication year 2019, excluding retracted works and paratext such as editorials and errata. The top 100 by citation count are listed; the percentile is the rank divided by the cohort size. 100 of the 100 entries have an abstract in OpenAlex. Counts were read on 29 October 2026 and will not be updated on this page, so a quoted rank stays verifiable. Full rules on the methodology page.

Other journals, same idea

Work with these 25 papers in Kahubi

  • The papers land in your library with their DOIs
  • Ask anything across all of them, with citations
  • Draft a literature review from the same sources

Free plan, no card. Your files stay private unless you share them.

Reading several of these?

Kahubi reads papers with you, keeps every citation traceable and drafts with sources you can check. Free plan, no card.