title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=983 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: Effects of coconut water on blood sugar and retina of rats with diabetes link: https://peerj.com/articles/10667 last-modified: 2021-01-29 description: BackgroundThis study aimed to evaluate the effects of coconut water on the general condition (fasting blood sugar and body weight) and retina of diabetic rats.MethodsForty-eight Sprague–Dawley male rats were divided into normal controls (NC), diabetes mellitus (DM), diabetes+coconut water (DM+CW), and diabetes+glibenclamide (DM+Gli) groups. After 4 weeks of normal feeding, coconut water was given to group III-DM+CW and 0.6 mg/kg glibenclamide to group IV–DM+Gli. The blood sugar, body weight, total retinal thickness, pathological changes, and VEGF expression in the retina were analyzed at different time points.ResultsThe fasting blood sugar was 4–6 mmol/L in group I-NC and continuously increased in group II-DM, whereas gradually decreased after the 4th experiment week in the remaining two groups. The rats, except in group I-NC, have lost weight. In group II-DM, the total retinal thickness was significantly increased after the 8th and 12th experiment week, and the pathological changes in retina were observed. VEGF was almost fully expressed in the ganglion cell layer and inner granular layer and partially expressed in the outer granular layer in group II-DM, and mainly expressed in the ganglion cell layer and inner layer in group I-NC, with a lighter color. Group III-DM + CW and group IV-DM + Gli demonstrated similar VEGF expression as in group I-NC.ConclusionsCoconut water has the potential to reduce blood sugar and diabetic retinal damage, serving as a candidate drug or nutrient for treating diabetes and its complications. creator: Yanan Dai creator: Li Peng creator: Xiaohua Zhang creator: Qingjing Wu creator: Jie Yao creator: Qiu Xing creator: Yunyan Zheng creator: Xiaobo Huang creator: Shaomei Chen creator: Qing Xie uri: https://doi.org/10.7717/peerj.10667 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2021 Dai et al. title: Multiple drivers behind mislabeling of fish from artisanal fisheries in La Paz, Mexico link: https://peerj.com/articles/10750 last-modified: 2021-01-29 description: Seafood mislabeling has the potential to mask changes in the supply of species due to overfishing, while also preventing consumers from making informed choices about the origin, quality and sustainability of their food. Thus, there is a need to understand mislabeling and analyze the potential causes behind it to propose solutions. We conducted a COI DNA barcoding study in La Paz, Baja California Sur, Mexico, with 74 samples from fish markets and 50 samples from restaurants. We identified 38 species sold under 19 commercial names, from which at least ∼80% came from local small-scale fisheries. Overall, 49 samples, representing 40% (95% CI [31.4–48.3]) were considered mislabeled in our samples. Based on analyses where species were assigned to three price categories, economic incentives were associated with approximately half of the mislabeling events observed, suggesting that other motivating factors might simultaneously be at play. Using a network approach to describe both mislabeling (when species are mislabeled as the focal species) and substitution (when the focal species is used as substitute for others), we calculated proxies for the net availability of each species in the market. We found that local fish landings were a significant predictor of the net availability of the 10 most important commercial species at retail, but this true availability was masked to the eyes of the final consumer by both mislabeling and substitution. We hypothesize that the level of supply of each species could help explain mislabeling and substitution rates, where species in low supply and high demand could show higher mislabeling rates and rarely be used as substitutes, while species in high supply and low demand could be used as substitutes for the preferred species. Other factors affecting mislabeling include national regulations that restrict the fishing or commercialization of certain species and local and global campaigns that discourage specific patterns of consumption. We discuss how these factors might influence mislabeling and propose some solutions related to communication and education efforts to this local and global challenge. creator: Adrian Munguia-Vega creator: Amy Hudson Weaver creator: José F. Domínguez-Contreras creator: Hoyt Peckham uri: https://doi.org/10.7717/peerj.10750 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2021 Munguia-Vega et al. title: A systematic review and realist synthesis on toilet paper hoarding: COVID or not COVID, that is the question link: https://peerj.com/articles/10771 last-modified: 2021-01-29 description: ObjectiveTo explore whether the coronavirus disease 2019 (COVID-19) pandemic is associated with toilet paper hoarding and to assess which risk factors are associated with the risk of toilet paper hoarding.DesignA systematic review and realist review were conducted.Data sourcesPubMed, Web of Science, Scopus and PsycINFO were searched (systematic review). PubMed, pre-prints and grey literature were also searched (realist review). The databases were searched from inception until October 2020.Study selectionThere were no restrictions on the study design.Outcomes and measuresFor the systematic review, toilet paper hoarding was the main outcome, and pathological use of toilet paper was the secondary outcome. For the realist review, the context-mechanisms-outcome (CMO) scheme included the COVID-19 pandemic (context), four proposed mechanisms, and one outcome (toilet paper hoarding). The four potential mechanisms were (1) gastrointestinal mechanisms of COVID-19 (e.g. diarrhoea), (2) social cognitive biases, (3) stress-related factors (mental illnesses, personality traits) and (4) cultural aspects (e.g. differences between countries).Eligibility criteria for selecting studiesAll studies of human populations were considered (including general population studies and clinical studies of patients suffering from mental health problems).ResultsThe systematic review identified 14 studies (eight studies for the main outcome, six studies for the secondary outcome). Three surveys identified the role of the COVID-19 threat in toilet paper hoarding in the general population. One study pointed to an association between a personality trait (conscientiousness) and toilet paper buying and stockpiling as well as an additional significant indirect effect of emotionality through the perceived threat of COVID-19 on toilet paper buying and stockpiling. Six case reports of pathological use of toilet paper were also identified, although none of them were associated with the COVID-19 pandemic. The realist review suggested that of all the mechanisms, social cognitive biases and a bandwagon effect were potential contributors to toilet paper hoarding in the general population. The stressful situation (COVID-19 pandemic) and some personality traits (conscientiousness) were found to be associated with toilet paper hoarding. Cultural differences were also identified, with relatively substantial effects of toilet paper hoarding in several Asian regions (Australia, Japan, Taiwan and Singapore).ConclusionsThe COVID-19 pandemic has been associated with a worldwide increase in toilet paper hoarding. Social media and social cognitive biases are major contributors and might explain some differences in toilet paper hoarding between countries. Other mental health-related factors, such as the stressful situation of the COVID-19 pandemic, fear of contagion, or particular personality traits (conscientiousness), are likely to be involved.RegistrationPROSPERO CRD42020182308 creator: Javier Labad creator: Alexandre González-Rodríguez creator: Jesus Cobo creator: Joaquim Puntí creator: Josep Maria Farré uri: https://doi.org/10.7717/peerj.10771 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2021 Labad et al. title: Occupation and life satisfaction among individuals with mental illness: the mediation role of self-reported psychophysiological health link: https://peerj.com/articles/10829 last-modified: 2021-01-29 description: BackgroundUnemployment can diminish physical, psychological and social health. In this context, research shows that people with mental illness have even more difficulties finding occupation. Thus, some countries, such as Sweden, strive after creating job opportunities for this specific group. We investigated the effect of having an occupation on life satisfaction among individuals with mental illness and whether self-reported physical and psychological health mediated the relationship between being (un)employed and life satisfaction.MethodTwo-hundred eighty-seven individuals (148 males, 134 females, and 5 missing information) with mental illness, who received support and services from Swedish Municipalities in Blekinge, self-reported occupation, life satisfaction, and physical and psychological health.ResultsParticipants who reported having an occupation reported also significantly higher levels of life satisfaction, physical health, and psychological health compared to those without occupation. Nevertheless, these differences were rather small (Eta2 < 0.06). Moreover, the indirect effect of having an occupation on life satisfaction through physical and psychological health was significant. Finally, the total indirect effect of physical and psychological health (i.e., psychophysiological health) accounted for 53% of the total effect of having an occupation on life satisfaction.ConclusionFor individuals with mental illness there seems to be an almost equal importance of indirect and direct effects of having an occupation on their levels of life satisfaction. More specifically, while there are differences in life satisfaction within this population in relation to having an occupation, having an occupation leads to the sense of good psychophysiological health, which in turn helps individuals with mental illness to feel satisfied with their lives. creator: Alexandre Granjard creator: Marko Mihailovic creator: Clara Amato creator: Maryam Kazemitabar creator: Franco Lucchese creator: Christian Jacobsson creator: Nobuhiko Kijima creator: Danilo Garcia uri: https://doi.org/10.7717/peerj.10829 license: https://creativecommons.org/licenses/by-nc/4.0 rights: © 2021 Granjard et al. title: Effects of no-tillage sowing on soil properties and forage wheat and Italian ryegrass yields in winter fallow paddy fields link: https://peerj.com/articles/10573 last-modified: 2021-01-28 description: In South China, it is common practice for the late rice (Oryza sativa) that is planted during the summer in the paddy fields after harvest to be used for fallowing or to plant winter forage crops. The land is ploughed before early rice planting. Both forage wheat (Triticum aestivum) and Italian ryegrass (Lolium multiflorum) have relatively high nutritional value, and planting them in winter fallow paddy fields could potentially address food shortages and provide quality forage for livestock. In this study, we examined the effects of no-tillage sowing 5 days before rice harvest (NB5), no-tillage sowing 1 day after rice harvest (NA1), and conventional tillage sowing (CK) 1 day after rice harvest on forage wheat and Italian ryegrass soil properties, dry matter (DM), and crude protein (CP) yields. Soil and plant samples were collected after three months of crop growth. The results showed that the NB5 and NA1 soil bulk density (0-20 cm soil layer) tended to increase when compared to that of the CK field. The NA1 treatment increased the total soil nitrogen and organic matter content. The enzyme activities and total soil porosity in the no-tillage forage wheat and Italian ryegrass fields tended to decrease, while the no-tillage water content and soil capillary porosity tended to increase when compared to that of the CK field. Overall, planting year significantly influenced soil chemical properties (except for total nitrogen) and enzyme activity, but crop type had no significant effect on soil physical-chemical properties (except for capillary moisture capacity) and enzyme activity. Sowing methods had no significant effects on the crop DM and CP yields. The DM yield was affected by the interaction between planting year and sowing methods, or between sowing methods and crop type. No-tillage also increased the number of species and aboveground weed biomass. We concluded that the best sowing method for forage wheat and Italian ryegrass in winter fallow paddy fields was no-tillage sowing following rice harvest. creator: Liuxing Xu creator: Guojian Tang creator: Jing Tian creator: Xiaoya Wang creator: Jianguo Zhang uri: https://doi.org/10.7717/peerj.10573 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2021 Xu et al. title: Effects of dietary fennel (Foeniculum vulgare Mill.) seed powder supplementation on growth performance, nutrient digestibility, small intestinal morphology, and carcass traits of broilers link: https://peerj.com/articles/10308 last-modified: 2021-01-28 description: BackgroundWith the increasing demands in livestock and poultry breeding and the growing number of food-borne diseases, it is necessary to practice food safety and develop strategies to produce healthy livestock. Fennel (Foeniculum vulgare Mill.) has been used as an additive in poultry production by some researchers, but there are few studies on the systemic beneficial effects of dietary fennel seed powder supplementation on broilers. Therefore, this study aimed to investigate the effect of dietary fennel seed powder supplementation on feed intake, the apparent metabolic rate of nutrients, intestinal morphology, and carcass traits in Cobb broilers.MethodsA single-factor experimental design was used. In total, 160 1-day-old Cobb broiler chicks were randomly assigned to four treatments, with four replicates each (n = 10/replicate). Broilers in the control (CN) group were fed a basal diet without fennel seed powder, and broilers in the treatment groups were fed a basal diet supplemented with 0.15% (LF), 0.30% (MF), or 0.45% (HF) fennel seed powder, respectively. Feeding trials lasted for 42 days under the conditions of ad libitum access to feed and water, and 24-h illumination. During the third and sixth weeks, digestive and metabolic assays were carried out. When the broilers were 42 days old, one chicken with a weight close to the average was selected from each repetition, euthanized by an intravenous injection of 5% sodium pentobarbital, and carcass traits were measured and intestinal samples were collected for morphological assessment.ResultsThere was no significant difference in growth performance of broilers (P > 0.05). The breast muscle percentage, fat width and fat width index, breast muscle area, and breast muscle area index of broilers in the LF group were higher than those in other groups (P < 0.05). Jejunum weight and length were higher in MF than in CN and LF broilers (P < 0.05). Additionally, duodenal villi height, ileal villi height, and ileal wall thickness were higher in MF than in CN broilers (P < 0.05). There were no significant differences in nutrient utilization among all groups (P > 0.05), except that the ash apparent metabolic rate in MF broilers at 21 days of age was higher than that in LF broilers (P < 0.05). In conclusion, dietary supplementation with a moderate concentration of fennel affects carcass performance, and intestinal morphology, and promotes the growth and development of broilers. creator: Huihui Liu creator: Jinlu Li creator: Shuqin Lin creator: Ting Liu creator: Chen Zheng uri: https://doi.org/10.7717/peerj.10308 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2021 Liu et al. title: Effect of salt stress in urban conditions on two Acer species with different sensitivity link: https://peerj.com/articles/10577 last-modified: 2021-01-28 description: BackgroundThe benefits of trees in urban areas include the following: an increase in ecosystem health, an increase in human health, the mitigation of the effects of heat and drought at microclimate level, the storage and sequestration of carbon, and a reduction in air pollution and noise. These ecosystem services can be provided only by trees that are in good health. The main cause of salt stress in urban environments is the use of de-icing salts on the streets in winter. Salt stress is a complex process that includes changes in plants on the physiological, histological, cellular and molecular levels, leading to limitations in nutrient uptake, disrupting the ionic balance of trees and resulting in the death of roadside trees. In response to salinity, trees have developed a variety of defence mechanisms that allow them to minimize the effects of stress and maintain homeostasis.MethodologyThe reactions of two species Acer species: A. platanoides and A. campestre, which have different sensitivities to the unfavourable conditions of the urban environments (mainly salt stress), were investigated. The research included two experiments: a field experiment with city trees and a controlled pot experiment with young trees treated with increasing doses of salt. In both experiments, the following were performed: an assessment of the health condition of the trees and the content of macroelements as well as the Cl and Na in leaves and a qualitative and quantitative analysis of polyprenols.ResultsA. campestre had a more specific strategy than A. platanoides for dealing with Na and Cl, which resulted in undamaged leaves. Under the same conditions, A. platanoides leaves contained more Cl and Na and were severely damaged. The disruption of the ion balance due to salt stress was lower in A. campestre than in A. platanoides. Compared with A. platanoides, A. campestre synthesized more polyprenols in the field experiment. This ability was acquired during the process of acclimation, because it occurred only in the mature trees in the field experiment and not in the young trees in the pot experiment.ConclusionsThe use of two experimental methods (i.e., the field and pot experiments) allowed for a more complete assessment of tree strategies to mitigate salt stress. A. campestre displayed a more specific strategy than A. platanoides. This strategy was based on several elements. A. campestre limited Cl and Na transport to the leaves, which resulted in a lack of damage to those organs. Under the same conditions, A. platanoides individuals contained more Cl and Na in their leaves and were seriously damaged. A. campestre synthesized larger amounts of polyprenols, which probably have the ability to mitigate salt stress. This ability was acquired during the process of acclimation, because it occurred only in the mature trees in the field experiment and was not observed in the young trees in the pot experiment. creator: Wojciech Dmuchowski creator: Aneta Baczewska-Dąbrowska creator: Dariusz Gozdowski creator: Paulina Brągoszewska creator: Barbara Gworek creator: Irena Suwara creator: Tadeusz Chojnacki creator: Adam Jóźwiak creator: Ewa Swiezewska uri: https://doi.org/10.7717/peerj.10577 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2021 Dmuchowski et al. title: Evaluation of effective quantum yields of photosystem II for CO2 leakage monitoring in carbon capture and storage sites link: https://peerj.com/articles/10652 last-modified: 2021-01-28 description: Vegetation monitoring can be used to detect CO2 leakage in carbon capture and storage (CCS) sites because it can monitor a large area at a relatively low cost. However, a rapidly responsive, sensitive, and cost-effective plant parameters must be suggested for vegetation monitoring to be practically utilized as a CCS management strategy. To screen the proper plant parameters for leakage monitoring, a greenhouse experiment was conducted by exposing kale (Brassica oleracea var. viridis), a sensitive plant, to 10%, 20%, and 40% soil CO2 concentrations. Water and water with CO2 stress treatments were also introduced to examine the parameters differentiating CO2 stress from water stresses. We tested the hypothesis that chlorophyl fluorescence parameters would be early and sensitive indicator to detect CO2 leakage. The results showed that the fluorescence parameters of effective quantum yield of photosystem II (Y(II)), detected the difference between CO2 treatments and control earlier than any other parameters, such as chlorophyl content, hyperspectral vegetation indices, and biomass. For systematic comparison among many parameters, we proposed an indicator evaluation score (IES) method based on four categories: CO2 specificity, early detection, field applicability, and cost. The IES results showed that fluorescence parameters (Y(II)) had the highest IES scores, and the parameters from spectral sensors (380–800 nm wavelength) had the second highest values. We suggest the IES system as a useful tool for evaluating new parameters in vegetation monitoring. creator: Wenmei He creator: Gayoung Yoo creator: Youngryel Ryu uri: https://doi.org/10.7717/peerj.10652 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2021 He et al. title: Monomorium (Hymenoptera: Formicidae) of the Arabian Peninsula with description of two new species, M. heggyi sp. n. and M. khalidi sp. n. link: https://peerj.com/articles/10726 last-modified: 2021-01-28 description: We present a revised and updated synoptic list of 44 Arabian Monomorium species, including two new species of the M. salomonis species-group: M. heggyisp. n., and M. khalidisp. n. We propose the following new synonyms: M. abeillei André (= M. wahibiense Collingwood & Agosti syn. n.); M. areniphilum Santschi (= M. fezzanense Collingwood & Agosti syn. n., =M. hemame Collingwood & Agosti syn. n. =M. marmule Collingwood & Agosti syn. n.); M. bicolor Emery (= M. phoenicum Santschi syn. n.); M. harithe Collingwood & Agosti (= M. najrane Collingwood & Agosti syn. n.); M. niloticum Emery (= M. matame Collingwood & Agosti syn. n.); and M. nitidiventre Emery (= M. yemene Collingwood & Agosti syn. n.). An illustrated key and distribution maps are presented for the treated species. Ecological and biological notes are given when available. The majority of Arabian Monomorium species (24) are endemic to the peninsula. All except one of the remaining species are more broadly ranging Afrotropical and Palearctic species, supporting the view of Arabia as a biogeographical crossroads between these two regions. Monomorium floricola (Jerdon), the sole species of Indomalayan origin, is recorded for the first time from the Arabian Peninsula. creator: Mostafa R. Sharaf creator: Amr A. Mohamed creator: Brendon E. Boudinot creator: James K. Wetterer creator: Francisco Hita Garcia creator: Hathal M. Al Dhafer creator: Abdulrahman S. Aldawood uri: https://doi.org/10.7717/peerj.10726 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2021 Sharaf et al. title: Biological effects of electron beam to target turning X-ray (EBTTX) on two freesia (Freesia hybrida) cultivars link: https://peerj.com/articles/10742 last-modified: 2021-01-28 description: Electron beam to target turning X-ray (EBTTX) is an emerging irradiation technology that can potentially accelerate the breeding process of plants. The biological effects of EBTTX irradiation on the two freesia cultivars (the red freesia and the purple freesia) were investigated by establishing an irradiation-mediated mutation breeding protocol. The germination rate, survival rate, plant height, leaf number and area, root number and length of the two freesia cultivars decreased following different irradiation doses (25, 50, 75, and 100-Gy). A high irradiation dose exhibited stronger inhibition effects on these plant growth parameters, and the survival rate of the two freesia cultivars was 0.00% following the 100-Gy irradiation treatment. The median lethal dose (LD50) based on survival rates was 54.28-Gy for the red freesia and 60.11-Gy for the purple freesia. The flowering rate, flower number, and pollen vigor were significantly decreased by irradiation treatment. At 75-Gy irradiation, the flowering rate, flower number and pollen viability of the two varieties reached the minimum, exhibiting strong inhibitory effects. Meanwhile, 75-Gy irradiation significantly decreased the chlorophyll content and increased the malondialdehyde (MDA) content of the two freesia cultivars. Furthermore, as the irradiation dose increased, the changes in the micro-morphology of the leaf epidermis and pollen gradually increased according to a scanning electron microscope (SEM) analysis. These results are expected to provide useful information for the mutation breeding of different freesia cultivars and other flowering plants. creator: Yi-rui Li creator: Ling Liu creator: Dan Wang creator: Li Chen creator: Hao Chen uri: https://doi.org/10.7717/peerj.10742 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2021 Li et al.