title: PeerJ
description:  Articles published in PeerJ
link: https://peerj.com/articles/index.rss3?journal=peerj&page=1281
creator: info@peerj.com PeerJ
errorsTo: info@peerj.com PeerJ
language: en

title: Arbuscular mycorrhizal fungi alter the food utilization, growth, development and reproduction of armyworm (Mythimna separata) fed on Bacillus thuringiensis maize
link: https://peerj.com/articles/7679
last-modified: 2019-09-12
description: BackgroundThe cultivation of Bt maize (maize genetically modified with Bacillus thuringiensis) continues to expand globally. Arbuscular mycorrhizal fungi (AMF), an important kind of microorganism closely related to soil fertility and plant nutrition, may influence the ecological risk of target lepidopteran pests in Bt crops.MethodsIn this study, transgenic Bt maize (Line IE09S034 with Cry1Ie vs. its parental line of non-Bt maize cv. Xianyu335) was inoculated with a species of AMF, Glomus caledonium (GC). Its effects on the food utilization, reproduction and development of armyworm, Mythimna separata, were studied in a potted experiment from 2017 to 2018.ResultsGC inoculation increased the AMF colonization of both modified and non-modified maize, and also increased the grain weight per plant and 1,000-grain weight of modified and non-modified maize. However, the cultivation of Bt maize did not significantly affect the AMF colonization. The feeding of M. separata with Bt maize resulted in a notable decrease in RCR (relative consumption rate), RGR (relative growth rate), AD (approximate digestibility), ECD (efficiency of conversion of digested food) and ECI (efficiency of conversion of ingested food) parameters in comparison to those observed in larvae fed with non-Bt maize in 2017 and 2018, regardless of GC inoculation. Furthermore, remarkable prolongation of larval life span and decreases in the rate of pupation, weight of pupa, rate of eclosion, fecundity and adult longevity of M. separata were observed in the Bt treatment regardless of GC inoculation during the two-year experiment. Also, when M. separata was fed with Bt maize, a significant prolongation of larval life and significant decreases in the pupal weight, fecundity and adult longevity of M. separata were observed when inoculated with GC. However, it was just the opposite for larvae fed with non-Bt maize that was inoculated with GC. The increased percentage of larval life-span, the decreased percentages of the food utilization, and the other indexes of reproduction, growth, and development of M. separata fed on Bt maize relative to non-Bt maize were all visibly lower when under GC inoculation in contrast to the CK.DiscussionIt is presumed that Bt maize has a marked adverse impact on M. separata development, reproduction and feeding, especially when in combination with the GC inoculation. Additionally, GC inoculation favors the effectiveness of Bt maize against M. separata larvae by reducing their food utilization ability, which negatively affects the development and reproduction of the armyworm. Thus, Bt maize inoculated with AMF (here, GC) can reduce the severe threats arising of armyworms, and hence the AMF inoculation may play an important ecological functions in the field of Bt maize ecosystem, with potentially high control efficiency for the target lepidopteran pests.
creator: Long Wang
creator: Sabin Saurav Pokharel
creator: Fajun Chen
uri: https://doi.org/10.7717/peerj.7679
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2019 Wang et al.

title: Mental practice in isolation improves cervical joint position sense in patients with chronic neck pain: a randomized single-blind placebo trial
link: https://peerj.com/articles/7681
last-modified: 2019-09-12
description: ObjectiveThe main objective of this trial was to assess whether action observation (AO) training and motor imagery (MI) produced changes in the cervical joint position sense (CJPS) both at the end of the intervention and 10 min postintervention compared with a placebo intervention in patients with nonspecific chronic neck pain (NSCNP).MethodsA single-blind placebo clinical trial was designed. A total of 30 patients with NSCNP were randomly assigned to the AO group, MI group or placebo observation (PO) group. CJPS in flexion, extension and rotation movements in both planes were the main variables.ResultsThe results obtained in the vertical plane showed that the AO group obtained greater improvements than the PO group in the CJPS in terms of cervical extension movement both at the end of the intervention and 10 min postintervention (p = .001, d = 1.81 and p = .004, d = 1.74, respectively), and also in cervical flexion movement, although only at 10 min after the intervention (p = .035, d = 0.72). In addition, the AO group obtained greater improvements than the MI group in the CJPS only at the end of the intervention in cervical extension movement (p = .041, d = 1.17). Regarding the left rotation cervical movement, both the MI and AO groups were superior to the PO group in both planes at the end of the intervention (p < .05, d > 0.80).ConclusionsAlthough both AO and MI could be a useful strategy for CJPS improvement, the AO group showed the strongest results. The therapeutic potential of the application of mental practice in a clinical context in the early stages of rehabilitation of NSCNP should be considered.
creator: Ferran Cuenca-Martínez
creator: Roy La Touche
creator: Jose Vicente León-Hernández
creator: Luis Suso-Martí
uri: https://doi.org/10.7717/peerj.7681
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2019 Cuenca-Martínez et al.

title: Simultaneous molecular docking of different ligands to His6-tagged organophosphorus hydrolase as an effective tool for assessing their effect on the enzyme
link: https://peerj.com/articles/7684
last-modified: 2019-09-12
description: BackgroundEnzymatic hydrolysis of N-acyl homoserine lactones (AHLs), which are signaling molecules responsible for the development of antibiotic resistance in gram-negative bacteria, is a potential solution to overcoming antibiotic resistance problem. It has been established that hexahistidine-tagged organophosphorus hydrolase (His6-OPH) exhibits lactonase activity against a number of AHLs and that the combined application of His6-OPH with β-lactam antibiotics leads to an increase in the efficiency of the action of both the enzyme and antibiotics. The use of computational methods can be an effective way to search for and select from the known antibiotics to find the most rational “partners” for combining with this enzyme and creating effective antibacterial agents with a dual (lactonase and antibacterial) functional activity.MethodsIn this study, by using AutoDock Vina and Gromacs softwares the molecular docking and the molecular dynamics methods were adopted to simulate models of puromycin, ceftiofur, and/or AHLs docked to the surface of a dimer molecule of His6-OPH and to study their binding properties. GABEDIT and GAMESS-US packages were used to generate and simulate electron densities of docked AHLs.ResultsInteractions of N-butyryl-DL-homoserine lactone (C4-HSL), N-(3-oxooctanoyl)-L-homoserine lactone (C8-HSL) and N-(3-oxododecanoyl)-L-homoserine lactone (C12-HSL) with His6-OPH dimer active sites in the presence of puromycin and ceftiofur were simulated and studied. The possible intersection of long-chain AHLs with antibiotic molecules in the active sites of the enzyme was revealed. The binding energies of antibiotics and AHLs with the His6-OPH surface were estimated. Statistically significant differences (p = 0.003) were observed between the values calculated for both C4-HSL and C12-HSL, whereas there were no statistically significant differences between the values of the other groups (p ≥ 0.100). The binding energies of AHLs with His6-OPH were slightly higher as compared with the binding energies of antibiotics with the enzyme. The dynamics of the most probable models obtained from docking were investigated. RMSD and RMSF analysis of His6-OPH-AHL complexes in the absence and presence of antibiotics were performed. The interaction energy values of antibiotics and AHLs with the His6-OPH were assessed. Significant increase of the AHLs steadiness in enzyme-substrate complexes in the presence of antibiotics was revealed. The interaction between His6-OPH and C12-HSL was established as thermodynamically more favored.ConclusionsIt has been established that the studied antibiotics puromycin and ceftiofur steady the enzyme-substrate complexes, but at the same time lead to a decrease in the long-chain AHL-hydrolytic activity of His6-OPH in such a combination as compared to a native enzyme, and, therefore, it should be taken into account when creating a therapeutic composition based on combining antibiotics with His6-OPH.
creator: Aysel Aslanli
creator: Elena Efremenko
uri: https://doi.org/10.7717/peerj.7684
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2019 Aslanli and Efremenko

title: Effect of biomimetic material on stress distribution in mandibular molars restored with inlays: a three-dimensional finite element analysis
link: https://peerj.com/articles/7694
last-modified: 2019-09-12
description: BackgroundAlthough biomimetic material has become increasingly popular in dental cosmetology nowadays, it remains unclear how it would affect the restored teeth during chewing. It is necessary to study the influence of biomimetic material on stress distribution in the restored teeth.MethodsEight three-dimensional finite element (FE) models were constructed and divided into two groups. Group 1 included the FE model of intact molar, and the FE models of inlay-restored molars fabricated from IPS e.max CAD, Lava Ultimate and biomimetic materials individually. Enamel was considered a homogeneous material. Group 2 included the FE models of intact molar and molars restored with inlays using IPS e.max CAD, Lava Ultimate and biomimetic materials individually, considering enamel as an inhomogeneous material.ResultsIn Group 1, compared with that in the intact molar, the maximum tensile stress (MTS) in the occlusal grooves decreased in the inlay-restored molars fabricated from IPS e.max CAD and was concentrated on the cavity floor at the buccal side in the inner dentin around inlay. When Lava Ultimate was selected, MTS decreased in the occlusal grooves and on the cavity floor but increased in the lateral walls. In the restored molar using biomimetic material, the MTS on the cavity floor was distributed more evenly than that in the molar using IPS e.max CAD, and no obvious changes were noted in the lateral walls. The same changes were observed in Group 2. No differences in the stress distribution pattern were noted among the FE models in Groups 1 and 2.ConclusionsMolars restored with inlays fabricated from biomimetic material exhibit a more uniform stress distribution in the dentin around restoration. The consideration of enamel as a homogeneous tissue is acceptable for analyzing the maximum principal stress distribution in the inlay-restored molar.
creator: Junxin Zhu
creator: Danmei Luo
creator: Qiguo Rong
creator: Xiaoyan Wang
uri: https://doi.org/10.7717/peerj.7694
license: https://creativecommons.org/licenses/by/4.0/
rights: © 2019 Zhu et al.

title: Relationship between ROS production, MnSOD activation and periods of fasting and re-feeding in freshwater shrimp Neocaridina davidi (Crustacea, Malacostraca)
link: https://peerj.com/articles/7399
last-modified: 2019-09-11
description: The middle region of the digestive system, the midgut of freshwater shrimp Neocaridina davidi is composed of a tube-shaped intestine and the hepatopancreas formed by numerous caeca. Two types of cells have been distinguished in the intestine, the digestive cells (D-cells) and regenerative cells (R-cells). The hepatopancreatic tubules have three distinct zones distinguished along the length of each tubule—the distal zone with R-cells, the medial zone with differentiating cells, and the proximal zone with F-cells (fibrillar cells) and B-cells (storage cells). Fasting causes activation of cell death, a reduction in the amount of reserve material, and changes in the mitochondrial membrane potential. However, here we present how the concentration of ROS changes according to different periods of fasting and whether re-feeding causes their decrease. In addition, the activation/deactivation of mitochondrial superoxide dismutase (MnSOD) was analyzed. The freshwater shrimps Neocaridina davidi (Crustacea, Malacostraca, Decapoda) were divided into experimental groups: animals starved for 14 days, animals re-fed for 4, 7, and 14 days. The material was examined using the confocal microscope and the flow cytometry. Our studies have shown that long-term starvation increases the concentration of free radicals and MnSOD concentration in the intestine and hepatopancreas, while return to feeding causes their decrease in both organs examined. Therefore, we concluded that a distinct relationship between MnSOD concentration, ROS activation, cell death activation and changes in the mitochondrial membrane potential occurred.
creator: Agnieszka Włodarczyk
creator: Grażyna Wilczek
creator: Piotr Wilczek
creator: Sebastian Student
creator: Anna Ostróżka
creator: Monika Tarnawska
creator: Magdalena Rost-Roszkowska
uri: https://doi.org/10.7717/peerj.7399
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2019 Włodarczyk et al.

title: Plant host and drought shape the root associated fungal microbiota in rice
link: https://peerj.com/articles/7463
last-modified: 2019-09-11
description: Background and AimWater is an increasingly scarce resource while some crops, such as paddy rice, require large amounts of water to maintain grain production. A better understanding of rice drought adaptation and tolerance mechanisms could help to reduce this problem. There is evidence of a possible role of root-associated fungi in drought adaptation. Here, we analyzed the endospheric fungal microbiota composition in rice and its relation to plant genotype and drought.MethodsFifteen rice genotypes (Oryza sativa ssp. indica) were grown in the field, under well-watered conditions or exposed to a drought period during flowering. The effect of genotype and treatment on the root fungal microbiota composition was analyzed by 18S ribosomal DNA high throughput sequencing. Grain yield was determined after plant maturation.ResultsThere was a host genotype effect on the fungal community composition. Drought altered the composition of the root-associated fungal community and increased fungal biodiversity. The majority of OTUs identified belonged to the Pezizomycotina subphylum and 37 of these significantly correlated with a higher plant yield under drought, one of them being assigned to Arthrinium phaeospermum.ConclusionThis study shows that both plant genotype and drought affect the root-associated fungal community in rice and that some fungi correlate with improved drought tolerance. This work opens new opportunities for basic research on the understanding of how the host affects microbiota recruitment as well as the possible use of specific fungi to improve drought tolerance in rice.
creator: Beatriz Andreo-Jimenez
creator: Philippe Vandenkoornhuyse
creator: Amandine Lê Van
creator: Arvid Heutinck
creator: Marie Duhamel
creator: Niteen Kadam
creator: Krishna Jagadish
creator: Carolien Ruyter-Spira
creator: Harro Bouwmeester
uri: https://doi.org/10.7717/peerj.7463
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2019 Andreo-Jimenez et al.

title: Monitoring public awareness about the endangered northern bald ibis: a case study involving primary school children as citizen scientists
link: https://peerj.com/articles/7569
last-modified: 2019-09-11
description: BackgroundCitizen science has evolved over the past decades by motivating members of the public to interact with scientists and actively participate in scientific research and monitoring. For this purpose, a proficient communication is mandatory in order to efficiently convey messages and reduce the gap of knowledge between scientists and lay people. In the present study, we aimed at evaluating the multiplying effect of children, who were trained to communicate their knowledge on an endangered bird species in order to engage the local community in the long-term ornithological monitoring of the free flying and individually marked colony of northern bald ibis (NBI, Geronticus eremita), which was established at the research station in 1997.MethodsPupils of the local primary schools were in regular contact with researchers, enjoyed outdoor encounters with the birds, and were invited to talk about their experience with as many people as possible. Later on, they acted as surveyors to assess the knowledge of the public on (i) the general knowledge about the species, (ii) specific knowledge about the local colony, and (iii) attitudes towards science. In two different years of evaluation (2012 and 2016) a total number of 387 persons were surveyed. The questions were generated together with the pupils and their teachers and the questionnaires were similar for both years of evaluation. All queries were in a closed format.ResultsOur results show an increase in the proportion of correct answers provided by the surveyed persons between the two years of evaluation. Education-based activities may encourage children to effectively act as multipliers of information and attitudes. This has the potential to induce sustainable changes with respect to attitude towards science, at least among local communities. Furthermore, the study suggests caution with the quality of some information reported by citizen scientists, which might be solved by more careful training actions and more specific information about local particularities. Even though the study would have gained more informative power with some additional precautions than in its current form, our findings recommend the empowerment of pupils as multipliers of scientific knowledge.
creator: Didone Frigerio
creator: Verena Puehringer-Sturmayr
creator: Brigitte Neuböck-Hubinger
creator: Gudrun Gegendorfer
creator: Kurt Kotrschal
creator: Katharina Hirschenhauser
uri: https://doi.org/10.7717/peerj.7569
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2019 Frigerio et al.

title: Genome-wide identification, characterization and expression pattern analysis of APYRASE family members in response to abiotic and biotic stresses in wheat
link: https://peerj.com/articles/7622
last-modified: 2019-09-11
description: APYRASEs, which directly regulate intra- and extra-cellular ATP homeostasis, play a pivotal role in the regulation of various stress adaptations in mammals, bacteria and plants. In the present study, we identified and characterized wheat APYRASE family members at the genomic level in wheat. The results identified a total of nine APY homologs with conserved ACR domains. The sequence alignments, phylogenetic relations and conserved motifs of wheat APYs were bioinformatically analyzed. Although they share highly conserved secondary and tertiary structures, the wheat APYs could be mainly categorized into three groups, according to phylogenetic and structural analysis. Additionally, these APYs exhibited similar expression patterns in the root and shoot, among which TaAPY3-1, TaAPY3-3 and TaAPY3-4 had the highest expression levels. The time-course expression patterns of the eight APYs in response to biotic and abiotic stress in the wheat seedlings were also investigated. TaAPY3-2, TaAPY3-3, TaAPY3-4 and TaAPY6 exhibited strong sensitivity to all kinds of stresses in the leaves. Some APYs showed specific expression responses, such as TaAPY6 to heavy metal stress, and TaAPY7 to heat and salt stress. These results suggest that the stress-inducible APYs could have potential roles in the regulation of environmental stress adaptations. Moreover, the catalytic activity of TaAPY3-1 was further analyzed in the in vitro system. The results showed that TaAPY3-1 protein exhibited high catalytic activity in the degradation of ATP and ADP, but with low activity in degradation of TTP and GTP. It also has an extensive range of temperature adaptability, but preferred relatively acidic pH conditions. In this study, the genome-wide identification and characterization of APYs in wheat were suggested to be useful for further genetic modifications in the generation of high-stress-tolerant wheat cultivars.
creator: Wenbo Liu
creator: Jun Ni
creator: Faheem Afzal Shah
creator: Kaiqin Ye
creator: Hao Hu
creator: Qiaojian Wang
creator: Dongdong Wang
creator: Yuanyuan Yao
creator: Shengwei Huang
creator: Jinyan Hou
creator: Chenghong Liu
creator: Lifang Wu
uri: https://doi.org/10.7717/peerj.7622
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2019 Liu et al.

title: Prevalence of generalized joint hypermobility, musculoskeletal injuries, and chronic musculoskeletal pain among American university students
link: https://peerj.com/articles/7625
last-modified: 2019-09-11
description: 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 participants classified within different categories (0; 1–4; 5–9) of Beighton scores and whether or not they reported having been injured. Male and female participants reported chronic pain of joints and neck or back at the same rates across the Beighton score categories. Female participants, however, reported higher pain intensity for chronic neck and back pain. This study increases knowledge about a correlation between GJH, musculoskeletal injuries, and chronic pain of joints, neck, and back in a university-aged population.
creator: Peter R. Reuter
creator: Kaylee R. Fichthorn
uri: https://doi.org/10.7717/peerj.7625
license: https://creativecommons.org/licenses/by/4.0/
rights: © 2019 Reuter and Fichthorn

title: Propagule pressure does not consistently predict the outcomes of exotic bird introductions
link: https://peerj.com/articles/7637
last-modified: 2019-09-11
description: Some have argued that the role of propagule pressure in explaining the outcomes of bird introductions is well-supported by the historical record. Here, we show that the data from a large published database (including 832 records with propagule information) do not support the conclusion that propagule pressure is the primary determinant of introduction success in birds. A few compendia of historical reports have been widely used to evaluate introduction success, typically by combining data from numerous species and introduction locations. Very few taxa, other than birds, have usable spatially explicit records of introductions over time. This availability of data inflates the perceived importance of bird analyses for addressing factors related to invasion success. The available data allow limited testing of taxonomic and site-level factors of introduction outcomes. We did find significant differences in effort and success probabilities among avian orders and across highly aggregated spatial regions. As a test of a standard and logical expectation of the propagule pressure hypothesis, we concentrated on introductions with the smallest propagules, because it is for these the hypothesis is most likely to be correct. We analyzed the effect of numbers released in small propagules (two through 10) for 227 releases. Weighted linear regression indicated no significant effect of propagule size for this range of release size. In fact, the mean success rate of 28% for propagules of 2–10 isn’t significantly different than that of 34% for propagules of 11–100. Following the example of previous analyses, we expanded the statistical test of propagule pressure to include the full range of release numbers. No significant support for the propagule pressure hypothesis was found using logistic regression with either logit or complementary log-log link functions.
creator: Michael P. Moulton
creator: Wendell P. Cropper
uri: https://doi.org/10.7717/peerj.7637
license: https://creativecommons.org/licenses/by/4.0/
rights: © 2019 Moulton and Cropper