title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=315 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: Unpredictable soil conditions can affect the prevalence of a microbial symbiosis link: https://peerj.com/articles/17445 last-modified: 2024-05-20 description: The evolution of symbiotic interactions may be affected by unpredictable conditions. However, a link between prevalence of these conditions and symbiosis has not been widely demonstrated. We test for these associations using Dictyostelium discoideum social amoebae and their bacterial endosymbionts. D. discoideum commonly hosts endosymbiotic bacteria from three taxa: Paraburkholderia, Amoebophilus and Chlamydiae. Three species of facultative Paraburkholderia endosymbionts are the best studied and give hosts the ability to carry prey bacteria through the dispersal stage to new environments. Amoebophilus and Chlamydiae are obligate endosymbiont lineages with no measurable impact on host fitness. We tested whether the frequency of both single infections and coinfections of these symbionts were associated with the unpredictability of their soil environments by using symbiont presence-absence data from D. discoideum isolates from 21 locations across the eastern United States. We found that symbiosis across all infection types, symbiosis with Amoebophilus and Chlamydiae obligate endosymbionts, and symbiosis involving coinfections were not associated with any of our measures. However, unpredictable precipitation was associated with symbiosis in two species of Paraburkholderia, suggesting a link between unpredictable conditions and symbiosis. creator: Trey J. Scott creator: Calum J. Stephenson creator: Sandeep Rao creator: David C. Queller creator: Joan E. Strassmann uri: https://doi.org/10.7717/peerj.17445 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2024 Scott et al. title: Influence of purple non-sulfur bacterial augmentation on soil nutrient dynamics and rice (Oryza sativa) growth in acidic saline-stressed environments link: https://peerj.com/articles/16943 last-modified: 2024-05-17 description: The aim of the current study was to assess the potency of the exopolymeric substances (EPS)-secreting purple non-sulfur bacteria (PNSB) on rice plants on acidic salt-affected soil under greenhouse conditions. A two-factor experiment was conducted following a completely randomized block design. The first factor was the salinity of the irrigation, and the other factor was the application of the EPS producing PNSB (Luteovulum sphaeroides EPS18, EPS37, and EPS54), with four replicates. The result illustrated that irrigation of salt water at 3–4‰ resulted in an increase in the Na+ accumulation in soil, resulting in a lower rice grain yield by 12.9–22.2% in comparison with the 0‰ salinity case. Supplying the mixture of L. sphaeroides EPS18, EPS37, and EPS54 increased pH by 0.13, NH4+ by 2.30 mg NH4+ kg−1, and available P by 8.80 mg P kg−1, and decreased Na+ by 0.348 meq Na+ 100 g−1, resulting in improvements in N, P, and K uptake and reductions in Na uptake, in comparison with the treatment without bacteria. Thus, the treatments supplied with the mixture of L. sphaeroides EPS18, EPS37, and EPS54 resulted in greater yield by 27.7% than the control treatment. creator: Nguyen Quoc Khuong creator: Nguyen Minh Nhat creator: Le Thi My Thu creator: Le Vinh Thuc uri: https://doi.org/10.7717/peerj.16943 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2024 Khuong et al. title: TPX2 upregulates MMP13 to promote the progression of lipopolysaccharide-induced osteoarthritis link: https://peerj.com/articles/17032 last-modified: 2024-05-17 description: PurposeThis study seeks to identify potential clinical biomarkers for osteoarthritis (OA) using bioinformatics and investigate OA mechanisms through cellular assays.MethodsDifferentially Expressed Genes (DEGs) from GSE52042 (four OA samples, four control samples) were screened and analyzed with protein-protein interaction (PPI) analysis. Overlapping genes in GSE52042 and GSE206848 (seven OA samples, and seven control samples) were identified and evaluated using Gene Set Enrichment Analysis (GSEA) and clinical diagnostic value analysis to determine the hub gene. Finally, whether and how the hub gene impacts LPS-induced OA progression was explored by in vitro experiments, including Western blotting (WB), co-immunoprecipitation (Co-IP), flow cytometry, etc.ResultBioinformatics analysis of DEGs (142 up-regulated and 171 down-regulated) in GSE52042 identified two overlapping genes (U2AF2, TPX2) that exhibit significant clinical diagnostic value. These genes are up-regulated in OA samples from both GSE52042 and GSE206848 datasets. Notably, TPX2, which AUC = 0.873 was identified as the hub gene. In vitro experiments have demonstrated that silencing TPX2 can alleviate damage to chondrocytes induced by lipopolysaccharide (LPS). Furthermore, there is a protein interaction between TPX2 and MMP13 in OA. Excessive MMP13 can attenuate the effects of TPX2 knockdown on LPS-induced changes in OA protein expression, cell growth, and apoptosis.ConclusionIn conclusion, our findings shed light on the molecular mechanisms of OA and suggested TPX2 as a potential therapeutic target. TPX2 could promote the progression of LPS-induced OA by up-regulating the expression of MMP13, which provides some implications for clinical research. creator: Jingtao Yu creator: Weiqi Wang creator: Zenghui Jiang creator: Huashun Liu uri: https://doi.org/10.7717/peerj.17032 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2024 Yu et al. title: Changes in the concentration of bone turnover markers in men after maximum intensity exercise link: https://peerj.com/articles/17258 last-modified: 2024-05-17 description: BackgroundPhysical activity is an important factor in modelling the remodelling and metabolism of bone tissue. The aim of the study was to evaluate the changes in indices demonstrating bone turnover in men under the influence of maximum-intensity exercise.MethodsThe study involved 33 men aged 20–25, divided into two groups: experimental (n = 15) and control (n = 18). People training medium- and long-distance running were assigned to the experimental group, and non-training individuals to the control. Selected somatic, physiological and biochemical indices were measured. The level of aerobic fitness was determined using a progressively increasing graded test (treadmill test for subjective fatigue). Blood samples for determinations were taken before the test and 60 minutes after its completion. The concentration of selected bone turnover markers was assessed: bone fraction of alkaline phosphatase (b-ALP), osteoclacin (OC), N-terminal cross-linked telopeptide of the alpha chain of type I collagen (NTx1), N-terminal propeptide of type I progolagen (PINP), osteoprotegerin (OPG). In addition, the concentration of 25(OH)D3 prior to the stress test was determined. Additionally, pre and post exercise, the concentration of lactates in the capillary blood was determined.ResultsWhen comparing the two groups, significant statistical differences were found for the mean level of: 25(OH)D3 (p = 0.025), b-ALP (p < 0.001), OC (p = 0.004) and PINP (p = 0.029) prior to the test. On the other hand, within individual groups, between the values pre and post the stress test, there were statistically significant differences for the average level of: b-ALP (p < 0.001), NTx1 (p < 0.001), OPG (p = 0.001) and PINP (p = 0.002).ConclusionA single-session maximum physical effort can become an effective tool to initiate positive changes in bone turnover markers. creator: Małgorzata Bagińska creator: Łukasz Marcin Tota creator: Małgorzata Morawska-Tota creator: Justyna Kusmierczyk creator: Tomasz Pałka uri: https://doi.org/10.7717/peerj.17258 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2024 Bagińska et al. title: Orbicularis oculi muscle activity during computer reading under different degrees of artificially-induced aniseikonia link: https://peerj.com/articles/17293 last-modified: 2024-05-17 description: BackgroundAniseikonia is a binocular vision disorder that has been associated with asthenopic symptoms. However, asthenopia has been evaluated with subjective tests that make difficult to determine the level of aniseikonia. This study aims to objectively evaluate the impact of induced aniseikonia at different levels on visual fatigue by measuring the orbicularis oculi muscle activity in the dominant and non-dominant eyes while performing a reading task.MethodsTwenty-four collegiate students (24.00 ± 3.86 years) participated in this study. Participants read a passage for 7 minutes under four degrees of aniseikonia (0%, 3%, 5% and 10%) at 50 cm. Orbicularis oculi muscle activity of the dominant and non-dominant eye was recorded by surface electromyography. In addition, visual discomfort was assessed after each task by completing a questionnaire.ResultsOrbicularis oculi muscle activity increased under induced aniseikonia (i.e., greater values for the 10% condition in comparison to 0%, and 3% conditions (p = 0.034 and p = 0.023, respectively)). No statistically significant differences were observed in orbicularis oculi muscle activity for the time on task and between the dominant and non-dominant eyes. Additionally, higher levels of subjective visual discomfort were observed for lower degrees of induced aniseikonia.ConclusionInduced aniseikonia increases visual fatigue at high aniseikonia degrees as measured by the orbicularis oculi muscle activity, and at low degrees as measured with subjective questionnaires. These findings may be of relevance to better understand the visual symptomatology of aniseikonia. creator: Beatriz Redondo creator: Jesus Vera creator: Rubén Molina creator: Alejandro Molina-Molina creator: Raimundo Jiménez uri: https://doi.org/10.7717/peerj.17293 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2024 Redondo et al. title: Bacteriogenic synthesis of morphologically diverse silver nanoparticles and their assessment for methyl orange dye removal and antimicrobial activity link: https://peerj.com/articles/17328 last-modified: 2024-05-17 description: Nanotechnology and nanoparticles have gained massive attention in the scientific community in recent years due to their valuable properties. Among various AgNPs synthesis methods, microbial approaches offer distinct advantages in terms of cost-effectiveness, biocompatibility, and eco-friendliness. In the present research work, investigators have synthesized three different types of silver nanoparticles (AgNPs), namely AgNPs-K, AgNPs-M, and AgNPs-E, by using Klebsiella pneumoniae (MBC34), Micrococcus luteus (MBC23), and Enterobacter aerogenes (MBX6), respectively. The morphological, chemical, and elemental features of the synthesized AgNPs were analyzed by using UV-Vis spectroscopy (UV-Vis), Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy-dispersive spectroscopy (EDX). UV-Vis absorbance peaks were obtained at 475, 428, and 503 nm for AgNPs-K, AgNPs-M, and AgNPs-E, respectively. The XRD analysis confirmed the crystalline nature of the synthesized AgNPs, having peaks at 26.2°, 32.1°, and 47.2°. At the same time, the FTIR showed bands at 599, 963, 1,693, 2,299, 2,891, and 3,780 cm−1 for all the types of AgNPs indicating the presence of bacterial biomolecules with the developed AgNPs. The size and morphology of the AgNPs varied from 10 nm to several microns and exhibited spherical to porous sheets-like structures. The percentage of Ag varied from 37.8% (wt.%) to 61.6%, i.e., highest in AgNPs-K and lowest in AgNPs-M. Furthermore, the synthesized AgNPs exhibited potential for environmental remediation, with AgNPs-M exhibiting the highest removal efficiency (19.24% at 120 min) for methyl orange dye in simulated wastewater. Further, all three types of AgNPs were evaluated for the removal of methyl orange dye from the simulated wastewater, where the highest dye removal percentage was 19.24% at 120 min by AgNPs-M. Antibacterial potential of the synthesized AgNPs assessment against both Gram-positive (GPB) Bacillus subtilis (MBC23), B. cereus (MBC24), and Gram-negative bacteria Enterococcus faecalis (MBP13) revealed promising results, with AgNPs-M, exhibiting the largest zone of inhibition (12 mm) against GPB B. megaterium. Such investigation exhibits the potential of the bacteria for the synthesis of AgNPs with diverse morphology and potential applications in environmental remediation and antibacterial therapy-based synthesis of AgNPs. creator: Bhakti Patel creator: Virendra Kumar Yadav creator: Reema Desai creator: Shreya Patel creator: Abdelfattah Amari creator: Nisha Choudhary creator: Haitham Osman creator: Rajat Patel creator: Deepak Balram creator: Kuang-Yow Lian creator: Dipak Kumar Sahoo creator: Ashish Patel uri: https://doi.org/10.7717/peerj.17328 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2024 Patel et al. title: Leeches Baicalobdella torquata feed on hemolymph but have a low effect on the cellular immune response of amphipod Eulimnogammarus verrucosus from Lake Baikal link: https://peerj.com/articles/17348 last-modified: 2024-05-17 description: Lake Baikal is one of the largest and oldest freshwater reservoirs on the planet with a huge endemic diversity of amphipods (Amphipoda, Crustacea). These crustaceans have various symbiotic relationships, including the rarely described phenomenon of leech parasitism on amphipods. It is known that leeches feeding on hemolymph of crustacean hosts can influence their physiology, especially under stressful conditions. Here we show that leeches Baicalobdella torquata (Grube, 1871) found on gills of Eulimnogammarus verrucosus (Gerstfeldt, 1858), one of the most abundant amphipods in the Baikal littoral zone, indeed feed on the hemolymph of their host. However, the leech infection had no effect on immune parameters such as hemocyte concentration or phenoloxidase activity and also did not affect glycogen content. The intensity of hemocyte reaction to foreign bodies in a primary culture was identical between leech-free and leech-infected animals. Artificial infection with leeches also had only a subtle effect on the course of a model microbial infection in terms of hemocyte concentration and composition. Despite we cannot fully exclude deleterious effects of the parasites, our study indicates a low influence of a few leeches on E. verrucosus and shows that leech-infected amphipods can be used at least for some types of ecophysiological experiments. creator: Anna Nazarova creator: Andrei Mutin creator: Denis Skafar creator: Nadezhda Bolbat creator: Sofya Sedova creator: Polina Chupalova creator: Vasiliy Pomazkin creator: Polina Drozdova creator: Anton Gurkov creator: Maxim Timofeyev uri: https://doi.org/10.7717/peerj.17348 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2024 Nazarova et al. title: Comparing trophic position estimates using bulk and compound specific stable isotope analyses: applying new approaches to mackerel icefish Champsocephalus gunnari link: https://peerj.com/articles/17372 last-modified: 2024-05-17 description: Quantifying the tropic position (TP) of an animal species is key to understanding its ecosystem function. While both bulk and compound-specific analyses of stable isotopes are widely used for this purpose, few studies have assessed the consistency between and within such approaches. Champsocephalus gunnari is a specialist teleost that predates almost exclusively on Antarctic krill Euphausia superba. This well-known and nearly constant trophic relationship makes C. gunnari particularly suitable for assessing consistency between TP methods under field conditions. In the present work, we produced and compared TP estimates for C. gunnari and its main prey using a standard bulk and two amino acid-specific stable isotope approaches (CSI-AA). One based on the difference between glutamate and phenylalanine (TPGlx-Phe), and the other on the proline-phenylalanine difference (TPPro-Phe). To do that, samples from C. gunnari, E. superba and four other pelagic invertebrate and fish species, all potential prey for C.gunnari, were collected off the South Orkney Islands between January and March 2019, analyzed using standard isotopic ratio mass spectrometry methods and interpreted following a Bayesian approach. Median estimates (CI95%) for C. gunnari were similar between TPbulk (3.6; CI95%: 3.0-4.8) and TPGlx-Phe(3.4; CI95%:3.2-3.6), and lower for TPPro-Phe (3.1; CI95%:3.0-3.3). TP differences between C. gunnari and E. superba were 1.4, 1.1 and 1.2, all compatible with expectations from the monospecific diet of this predator (ΔTP=1). While these results suggest greater accuracy for Glx-Phe and Pro-Phe, differences observed between both CSI-AA approaches suggests these methods may require further validation before becoming a standard tool for trophic ecology. creator: Jose Antonio Canseco creator: Edwin J. Niklitschek creator: Claudio Quezada-Romegialli creator: Chris Yarnes creator: Chris Harrod uri: https://doi.org/10.7717/peerj.17372 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2024 Canseco et al. title: Occurrence patterns of sympatric forest wallabies: assessing the influence of structural habitat attributes on the coexistence of Thylogale thetis and T. stigmatica link: https://peerj.com/articles/17383 last-modified: 2024-05-17 description: BackgroundWe studied the occurrence of two sympatric wallabies, the red-necked pademelon (Thylogale thetis) and the red-legged pademelon (T. stigmatica) in northeastern New South Wales, Australia in relation to structural habitat attributes. At our study site, both species inhabit closed forest environments and have overlapping distributions, but T. thetis leaves the forest at night to graze adjacent grassy forest edges whereas T. stigmatica remains within the forest and browses forest vegetation. The objectives of the study were to investigate how structural attributes of two forest types, wet sclerophyll forest and rainforest, relate to the fine-scale occurrence of these two wallaby species within the forested environment.MethodsWe gathered occurrence data from 48 camera trap stations divided equally between rainforest and wet sclerophyll forest. At each camera point, we also measured a range of structural habitat attributes to determine habitat affiliations for the two Thylogale species. Principal component analyses were used to describe major trends in habitat, and generalised linear models were used to describe the efficacy of the variables in predicting habitat occurrence of each species.ResultsThe number of occurrences of Thylogale thetis was significantly greater than occurrences of T. stigmatica, which was driven by significantly greater occurrences of T. thetis in wet sclerophyll forest. There was both spatial and temporal partitioning between the two species; there was a significant difference in the occurrences of the two species at individual cameras and T. stigmatica had a different activity schedule than T. thetis in wet sclerophyll forest, where the latter reached its greatest rate of occurrence. At a finer (camera station) scale, occurrences of T. thetis increased with proximity to roads and grassy edges and at sites that were less rocky and less steep. T. stigmatica occurrence increased in the presence of rainforest elements like vines, palms and ferns, more ground-level cover and tree-fall gaps and at sites with fewer emergent eucalypts.ConclusionOur findings have implications for managing these pademelons and their habitats. T. thetis is a common species that was encountered more often than T. stigmatica, and it responded positively to human disturbance like roadsides and grassy edges, presumably because these areas provided good grazing opportunities. By comparison, T. stigmatica is a threatened species, and it responded to natural disturbance like tree-fall gaps where lateral cover was greater, and where rainforest food plants may be more abundant. Our results suggest, therefore, that conservation of the threatened T. stigmatica requires the preservation of intact rainforest. creator: Lucy E.V. Smith creator: Nigel R. Andrew creator: Karl Vernes uri: https://doi.org/10.7717/peerj.17383 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2024 Smith et al. title: Validity and reliability of My Jump 2® app to measure the vertical jump on elite women beach volleyball players link: https://peerj.com/articles/17387 last-modified: 2024-05-17 description: PurposeThe aim of this study was to assess the reliability and validity of the My Jump 2® app in measuring jump height, flight time, and peak power among elite women beach volleyball players on sand surfaces.MethodsEleven elite female beach volleyball players (aged 23.6 ± 6.2 years; weight 66.3 ± 5.8 kg; height 174.4 ± 5.8 cm; with 8.4 ± 4.8 years of professional experience) participated in this study. Each player performed six countermovement jumps in a wooden box filled with sand on a force platform while simultaneously recording a video for subsequent analysis using the My Jump 2® app.ResultsWe found excellent agreement for flight time, jump height and peak power between observers (ICC = 0.92, 0.91 and 0.97, respectively). No significant differences between force platform and My Jump 2® app were detected in the values obtained for the three variables (P > 0.05). For the force platform and the My Jump 2® app, we found a good agreement measuring jump height and flight time (ICC = 0.85 and 0.85, respectively). However, we only found a moderate agreement for peak power (ICC = 0.64). The difference in jump height showed a limit of agreement between −4.10 and 4.74 cm in Bland-Altman, indicating a high level of agreement between the two measurement tools.ConclusionBased on our findings, the My Jump 2® app reveals a valid tool for measuring jump height and flight time of CMJ on sand surfaces. However, more caution is needed when measuring peak power. creator: Alexandre Igor Araripe Medeiros creator: Geovani Messias da Silva creator: Francisco Oliveira Neto creator: Mário Simim creator: Túlio Banja creator: Victor S. Coswig creator: José Afonso creator: Ana Ramos creator: Isabel Mesquita uri: https://doi.org/10.7717/peerj.17387 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2024 Medeiros et al.