title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=652 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: The antioxidant system response to drought-stressed Diospyros lotus treated with exogenous melatonin link: https://peerj.com/articles/13936 last-modified: 2022-09-19 description: Drought is one of the major abiotic stresses adversely impacting the growth of persimmon, which is a widely cultivated traditional fruit tree in North China. Melatonin is a bio-stimulator involved in mediating plant responses to drought. The role of exogenous melatonin application in the drought tolerance of Diospyros lotus was examined under drought stress with different doses of melatonin (0, 10, 50, and 100 µM). Exogenous melatonin application significantly mitigated the adverse effects of drought stress on chlorophyll fluorescence, lipid peroxidation, reactive oxygen species (ROS) accumulation and nitric oxide (NO) content. The 100-µM melatonin application produced the most beneficial impacts against drought stress. The melatonin-enhanced tolerance could be attributed to improved antioxidant enzymes, reduced drought-induced ROS accumulation, and lipid peroxidation. Melatonin application activated major antioxidant enzymes such as superoxide dismutase, catalase, peroxidase, glutathione reductase, and ascorbate peroxidase. Interestingly, NO concentration was significantly higher in 10 and 50 µM melatonin treatments and lower in 100 µM melatonin treatment compared to the control. Moreover, exogenous melatonin application affected the mRNA transcript levels of several genes involved in ROS metabolism, including DlRBOHA, DlSOD, DlCAT, and DlPOD. Hence, the responses of Diospyros lotus to drought varied with different doses of melatonin. Our results provide a concrete insight into the effects of melatonin with varying doses in alleviating drought as well as a platform for its potential application in the related fields. creator: Peng Zhang creator: Yi Hu creator: Ruijin Zhou creator: Xiaona Zhang creator: Huiling Hu creator: Dongmei Lang uri: https://doi.org/10.7717/peerj.13936 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Zhang et al. title: The effect of enhanced variability after performance stabilization through constant practice link: https://peerj.com/articles/13733 last-modified: 2022-09-16 description: There is a controversy about the benefits of variable practice on motor learning. This study aimed to analyze the effect of variable practice after the learner stabilized their performance. Thirty-two healthy adults performed a computer-simulated discrete accuracy task in which they had to release a virtual ball to try to hit a target. After a pre-test, the participants were distributed into three training groups: constant practice, variable practice and a group that started practicing in constant conditions, and when their performance stabilized, changed to variable practice. The participants performed 44 sets of 10 repetitions of the task. A post-test and two retention tests were carried out. Variable practice did not show a significant improvement compared to constant practice. Variable practice did not show higher benefits even when performance was stabilized through constant practice, but its effects seem to be modulated by the initial variability of the learners. creator: Carmen Ruano creator: Carla Caballero creator: Francisco J. Moreno uri: https://doi.org/10.7717/peerj.13733 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Ruano et al. title: Molecular and behavioral studies reveal differences in olfaction between winter and summer morphs of Drosophila suzukii link: https://peerj.com/articles/13825 last-modified: 2022-09-16 description: Spotted-wing drosophila, Drosophila suzukii (Matsumura), is a major economic pest of several fruit crops in Europe, North and South America, and other parts of the world because it oviposits in ripening thin-skinned fruits. This vinegar fly exhibits two distinct morphotypes: a summer and a winter morph. Although adaptations associated with the winter morph enhance this invasive pest’s capacity to survive in cold climates, winter is still a natural population bottleneck. Since monitoring early spring populations is important for accurate population forecasts, understanding the winter morph’s response to olfactory cues may improve current D. suzukii management programs. In this study, a comparative transcriptome analysis was conducted to assess gene expression differences between the female heads of the two D. suzukii morphs, which showed significant differences in 738 genes (p ≤ 0.0001). Out of twelve genes related to olfaction determined to be differentially expressed in the transcriptome, i.e., those related to location of food sources, chemosensory abilities, and mating behavior, nine genes were upregulated in the winter morph while three were downregulated. Three candidate olfactory-related genes that were most upregulated or downregulated in the winter morph were further validated using RT-qPCR. In addition, behavioral assays were performed at a range of temperatures to confirm a differing behavioral response of the two morphs to food odors. Our behavioral assays showed that, although winter morphs were more active at lower temperatures, the summer morphs were generally more attracted to food odors. This study provides new insights into the molecular and behavioral differences in response to olfactory cues between the two D. suzukii morphs that will assist in formulating more effective monitoring and physiological-based control tools. creator: Timothy W. Schwanitz creator: James J. Polashock creator: Dara G. Stockton creator: Cesar Rodriguez-Saona creator: Diego Sotomayor creator: Greg Loeb creator: Chloe Hawkings uri: https://doi.org/10.7717/peerj.13825 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Schwanitz et al. title: Ontogenetic, dietary, and environmental shifts in Mesosauridae link: https://peerj.com/articles/13866 last-modified: 2022-09-16 description: Mesosaurs are the first secondarily aquatic amniotes and one of the most enigmatic clades of reptiles from the early Permian. They have long puzzled paleontologists with their unique morphologies: possessing an elongated skull with thin needle-like teeth, a long neck, large webbed hindlimbs, banana-shaped pachyosteosclerotic ribs, and a long tail. Here, we look at a large dataset of morphometric measurements from 270 mesosaur specimens in collections around the world. These measurements characterize skull, tooth, and limb proportions and their variation with size. This data presents evidence of surprising ontogenetic changes in these animals as well as new insights into their taxonomy. Our results support the recent hypothesis that Mesosaurus tenuidens is the only valid species within Mesosauridae and suggest that “Stereosternum tumidum” and “Brazilosaurus sanpauloensis” represent immature stages or incomplete specimens of Mesosaurus by showing that all three species occupy an incomplete portion of the overall size range of mesosaurs. Under the single-species hypothesis, we highlight a number of ontogenetic trends: (1) a reduction in skull length accompanied by an elongation of the snout within the skull, (2) an elongation of teeth, (3) a reduction in hind limb length, and (4) a reduction in manus length. Concurrent with these changes, we hypothesize that mesosaurs went through a progressive ecological shift during their growth, with juveniles being more common in shallow water deposits, whereas large adults are more frequent in pelagic sediments. These parallel changes suggest that mesosaurs underwent a diet and lifestyle transition during ontogeny, from an active predatory lifestyle as juveniles to a more filter-feeding diet as adults. We propose that this change in lifestyle and environments may have been driven by the pursuit of different food sources, but a better understanding of the Irati Sea fauna will be necessary to obtain a more definitive answer to the question of young mesosaur diet. creator: Antoine Verrière creator: Jörg Fröbisch uri: https://doi.org/10.7717/peerj.13866 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Verrière and Fröbisch title: Assembling microbial communities: a genomic analysis of a natural experiment in neotropical bamboo internodes link: https://peerj.com/articles/13958 last-modified: 2022-09-16 description: Microbes participate in ecological communities, much like multicellular organisms. However, microbial communities lack the centuries of observation and theory describing and predicting ecological processes available for multicellular organisms. Here, we examine early bacterial community assembly in the water-filled internodes of Amazonian bamboos from the genus Guadua. Bamboo stands form distinct habitat patches within the lowland Amazonian rainforest and provide habitat for a suite of vertebrate and invertebrate species. Guadua bamboos develop sealed, water-filled internodes as they grow. Internodes are presumed sterile or near sterile while closed, but most are eventually opened to the environment by animals, after which they are colonized by microbes. We find that microbial community diversity increases sharply over the first few days of environmental exposure, and taxonomic identity of the microbes changes through this time period as is predicted for early community assembly in macroscopic communities. Microbial community taxonomic turnover is consistent at the bacteria phylum level, but at the level of Operational Taxonomic Units (OTUs), internode communities become increasingly differentiated through time. We argue that these tropical bamboos form an ideal study system for microbial community ecology due to their near-sterile condition prior to opening, relatively consistent environment after opening, and functionally limitless possibilities for replicates. Given the possible importance of opened internode habitats as locations of transmission for both pathogenic and beneficial microbes among animals, understanding the microbial dynamics of the internode habitat is a key conservation concern for the insect and amphibian species that use this microhabitat. creator: Sonia Ahluwalia creator: Iris Holmes creator: Rudolf von May creator: Daniel L. Rabosky creator: Alison R. Davis Rabosky uri: https://doi.org/10.7717/peerj.13958 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Ahluwalia et al. title: Effects of L-carnitine supplementation for women with polycystic ovary syndrome: a systematic review and meta-analysis link: https://peerj.com/articles/13992 last-modified: 2022-09-16 description: BackgroundPolycystic ovary syndrome (PCOS) is a disorder in reproductive age women and is characterized by hyperandrogenic anovulation and oligo-amenorrhea, which leads to infertility. Anovulation in PCOS is associated with low follicle-stimulating hormone levels and the arrest of antral follicle development in the final stages of maturation. L-carnitine (LC) plays a role in fatty acid metabolism, which is found to be lacking in PCOS patients. This systematic review and meta-analysis aimed to determine the effectiveness of LC supplementation for patients with PCOS.MethodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Psychological Information Database (PsycINFO), and the World Health Organization International Clinical Trials Registry Platform for all randomized control trials, comparing LC alone or in combination with other standard treatments for the treatment of PCOS from inception till June 2021. We independently screened titles and abstracts to identify available trials, and complete texts of the trials were checked for eligibility. Data on the methods, interventions, outcomes, and risk of bias from the included trials were independently extracted by the authors. The estimation of risk ratios and mean differences with a 95 percent confidence interval (CI) was performed using a random-effects model.ResultsNine studies with 995 participants were included in this review. Five comparison groups were involved. In one comparison group, LC reduced the fasting plasma glucose (FPG) (mean differences (MD) −5.10, 95% CI [−6.25 to −3.95]; P = 0.00001), serum low-density lipoprotein (LDL) (MD −25.00, 95% CI [−27.93 to −22.07]; P = 0.00001), serum total cholesterol (MD −21.00, 95% CI [−24.14 to −17.86]; P = 0.00001), and serum triglyceride (TG) (MD −9.00, 95% CI [−11.46 to −6.54]; P = 0.00001) with moderate certainty of evidence. Another comparison group demonstrated that LC lowers the LDL (MD −12.00, 95% CI [−15.80 to −8.20]; P = 0.00001), serum total cholesterol (MD −24.00, 95% CI [−27.61 to −20.39]; P = 0.00001), and serum TG (MD −19.00, 95% CI [−22.79 to −15.21]; P = 0.00001) with moderate certainty of evidence.ConclusionThere was low to moderate certainty of evidence that LC improves Body Mass Index (BMI) and serum LDL, TG, and total cholesterol levels in women with PCOS. creator: Mohd Falihin Mohd Shukri creator: Mohd Noor Norhayati creator: Salziyan Badrin creator: Azidah Abdul Kadir uri: https://doi.org/10.7717/peerj.13992 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Mohd Shukri et al. title: Understanding the distribution and fine-scale habitat selection of mesocarnivores along a habitat quality gradient in western Himalaya link: https://peerj.com/articles/13993 last-modified: 2022-09-16 description: Background: Human activities have resulted in a rapid increase of modified habitats in proximity to wildlife habitats in the Himalaya. However, it is crucial to understand the extent to which human habitat modification affects wildlife. Mesocarnivores generally possess broader niches than large carnivores and adapt quickly to human activities. Here, we use a case study in the western Himalaya to test the hypothesis that human disturbance influenced mesocarnivore habitat use.Methods: We used camera trapping and mitochondrial DNA-based species identification from faecal samples to obtain mesocarnivore detections. We then compared the responses of mesocarnivores between an anthropogenic site and a less disturbed park along a contiguous gradient in habitat quality. The non-linear pattern in species-specific habitat selection and factors responsible for space usage around villages was captured using hierarchical generalized additive modelling (HGAM) and non-metric multidimensional scaling (NMDS) ordination.Results: Wildlife occurrences along the gradient varied by species. Leopard cat and red fox were the only terrestrial mesocarnivores that occurred in both anthropogenic site and park. We found a shift in habitat selection from less disturbed habitat in the park to disturbed habitat in anthropogenic site for the species detected in both the habitat types. For instance, red fox showed habitat selection towards high terrain ruggedness (0.5 to 0.7 TRI) and low NDVI (−0.05 to 0.2) in the park but no such specific selection in anthropogenic site. Further, leopard cat showed habitat selection towards moderate slope (20°) and medium NDVI (0.5) in park but no prominent habitat selections in anthropogenic site. The results revealed their constrained behaviour which was further supported by the intensive site usage close to houses, agricultural fields and human trails in villages.Conclusions: Our results indicate shifts in habitat selection and intensive site usage by mesocarnivores in the human-modified habitat. In future, this suggests the possibility of conflict and disease spread affecting both the people and wildlife. Therefore, this study highlights the requisite to test the wildlife responses to rapidly growing human expansions in modified habitats to understand the extent of impact. The management strategies need to have an integrated focus for further expansions of modified habitat and garbage disposal strategies, especially in the human-wildlife interface area. creator: Meghna Bandyopadhyay creator: A. Cole Burton creator: Sandeep Kumar Gupta creator: Ramesh Krishnamurthy uri: https://doi.org/10.7717/peerj.13993 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Bandyopadhyay et al. title: Shifts in water column microbial composition associated to lakes with different trophic conditions: “Lagunas de Montebello” National Park, Chiapas, México link: https://peerj.com/articles/13999 last-modified: 2022-09-16 description: Eutrophication is a global problem causing the reduction of water quality and the loss of ecosystem goods and services. The lakes of the “Lagunas de Montebello” National Park (LMNP), Chiapas, Mexico, not only represent unique and beautiful natural scenic sites in southern Mexico but are also a national protected area and RAMSAR site. Unfortunately, some of these lakes started showing eutrophication signs since 2003. Anthropogenic activities (e.g., land-use change from forested to agricultural and urban development) are leading to water quality and trophic state alterations of the lakes of the LMNP. This study shows the results of a coupled limnological characterization and high-throughput sequencing of the V4 hypervariable region of the 16S rRNA gene to analyze the microbial composition of the water column in a set of oligotrophic and eutrophic lakes. Chlorophyll a (Chl-a) was the main environmental parameter correlated with the trophic conditions of the lakes. Although the microbial diversity was similar, the microbial composition changed significantly from oligo to eutrophic lakes. Proteobacteria, Firmicutes, and Cyanobacteria were the main components of oligotrophic lakes, and Cyanobacteria, Proteobacteria, and Bacteroidetes of eutrophic lakes. While Acinetobacter (Proteobacteria) and Cyanobium (a unicellular cyanobacterium) dominated in oligotrophic lakes, the filamentous, bloom-forming, and toxin-producing cyanobacteria Planktothrix was the dominant genus in eutrophic lakes. High-throughput sequencing allowed the detection of changes in the composition of the microbial component in oligotrophic lakes, suggesting a shift towards eutrophication, highlighting the relevance of sensitive monitoring protocols of these ecosystems to implement remediation programs for eutrophicated lakes and conservation strategies for those yet pristine. creator: Alfredo Yanez-Montalvo creator: Bernardo Aguila creator: Elizabeth Selene Gómez-Acata creator: Miriam Guerrero-Jacinto creator: Luis A. Oseguera creator: Luisa I. Falcón creator: Javier Alcocer uri: https://doi.org/10.7717/peerj.13999 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Yanez-Montalvo et al. title: Sex differences in peripheral monoamine transmitter and related hormone levels in chronic stress mice with a depression-like phenotype link: https://peerj.com/articles/14014 last-modified: 2022-09-16 description: BackgroundsChronic stress could induce depression-like phenotype in animal models. Previous data showed that sex differences exist after chronic stress model establishment, however, the detailed information about the difference of blood biochemical indexes is not clear. In this study, we aim to supply comparison of monoamine transmitters and related hormone markers in serum between male and female depressed mice, and in order to better understand the sex difference in transmitters and hormone levels in depression occurrence and development.MethodsSixty C57BL/6 mice (both male and female) were divided into two groups by gender. Same gender mice were then divided randomly into the non-treated control group and chronic stress group which was exposed to 8 weeks of chronic unpredictable mild stress (CUMS). Depression-like behavior was assessed with open-field test and sucrose preference test. Blood sample was collected and monoamine transmitter and related hormone in serum were measured by ELISA.ResultsThe depression-like phenotype mice model was established successfully after 8 weeks of chronic stress. The locomotion activity scores in male stressed mice declined more than that in female stressed mice, while the exploratory behavior scores in female stressed mice declined more than that in male stressed mice. Compared to non-treated control group mice, mice in the chronic stress group in response to stress showed greater declines in monoamine transmitters (5-HT, dopamine, norepinephrine) and sex hormones (androgen, estrogen, oxytocin and prolactin), while stress hormones (adrenaline, corticosterone and ACTH) were significantly increased. The decrease of norepinephrine, androgen and estrogen in female stressed mice was greater than in male stressed mice, whereas the 5-HT and oxytocin in male stressed mice decreased more than in female stressed mice, and the corticosterone in male stressed mice increased more than in female stressed mice.ConclusionSex differences of monoamine transmitter and related hormone levels in serum occurred in chronic stress induced depression-like phenotype mice model. It may provide a useful reference to guide precise antidepressant treatment in different gender population in clinical care. creator: Yitian Chen creator: Weijia Cai creator: Canye Li creator: Zuanjun Su creator: Zhijun Guo creator: Zhuman Li creator: Chen Wang creator: Feng Xu uri: https://doi.org/10.7717/peerj.14014 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Chen et al. title: Bayesian estimation of rainfall dispersion in Thailand using gamma distribution with excess zeros link: https://peerj.com/articles/14023 last-modified: 2022-09-16 description: The gamma distribution is commonly used to model environmental data. However, rainfall data often contain zero observations, which violates the assumption that all observations must be positive in a gamma distribution, and so a gamma model with excess zeros treated as a binary random variable is required. Rainfall dispersion is important and interesting, the confidence intervals for the variance of a gamma distribution with excess zeros help to examine rainfall intensity, which may be high or low risk. Herein, we propose confidence intervals for the variance of a gamma distribution with excess zeros by using fiducial quantities and parametric bootstrapping, as well as Bayesian credible intervals and highest posterior density intervals based on the Jeffreys’, uniform, or normal-gamma-beta prior. The performances of the proposed confidence interval were evaluated by establishing their coverage probabilities and average lengths via Monte Carlo simulations. The fiducial quantity confidence interval performed the best for a small probability of the sample containing zero observations (δ) whereas the Bayesian credible interval based on the normal-gamma-beta prior performed the best for large δ. Rainfall data from the Kiew Lom Dam in Lampang province, Thailand, are used to illustrate the efficacies of the proposed methods in practice. creator: Wansiri Khooriphan creator: Sa-Aat Niwitpong creator: Suparat Niwitpong uri: https://doi.org/10.7717/peerj.14023 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Khooriphan et al.