title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=1370 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: No association of COMT with insight problem solving in Chinese college students link: https://peerj.com/articles/6755 last-modified: 2019-04-15 description: Genes involved in dopamine (DA) neurotransmission, such as the catechol-O-methyltransferase gene (COMT), have been suggested as key genetic candidates that might underlie the genetic basis of insight. In a sample of Chinese college students, this study examined whether COMT was associated with individual differences in the ability to solve classic insight problems. The results demonstrated that COMT was not associated with insight problem solving and there was no gender-dependent effect. This study, together with previous studies, raises the possibility of a complex relationship between COMT and insight problem solving. creator: Xiaolei Yang creator: Jinghuan Zhang creator: Shun Zhang uri: https://doi.org/10.7717/peerj.6755 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2019 Yang et al. title: Head louse egg and nit remover—a modern “Quest for the Holy Grail” link: https://peerj.com/articles/6759 last-modified: 2019-04-15 description: BackgroundThe eggs of head lice are fixed to the hair of their hosts by means of a persistent glue-like fixative that is not chemically bound to the substrate. Eggshells stuck to hairs after successfully treating the infestation are a cosmetic issue and a source of misunderstanding about whether the infestation is eliminated. Hitherto, no effective treatment to loosen louse eggs and nits has been found.MethodsAn extensive screening of surface active compounds, oils, esters, and other cosmetic lubricants used a slip-peel device to measure the forces required to release the grip of the fixative. Promisingly effective compounds were formulated into suitable carriers for further testing. The most effective combination formulation was tested, as a commercial product (Hedrin Stubborn Egg Loosening Lotion), in a usage study of 15 children with nits, in which one half of the head was combed only on damp hair and the other half combed after a 10 min treatment using the product.ResultsLaboratory tests of the forces required to remove nits found that pelagonic acid derivatives, particularly isononyl isononanoate, in the presence of a polymeric gelling agent and water, were most effective to reduce the initial grip of the fixative as well as reducing friction as the eggshell is drawn along the hair shaft and that the final product was significantly (p < 0.05) more effective than several other marketed materials. In the usage study significantly (p = 0.01046) more louse eggs and nits were removed after treatment with the gel.DiscussionThe product developed through this study is the first with a demonstrable efficacy for loosening the grip of the louse egg fixative from hair. Consequently, until now, and despite the availability of effective pediculicidal treatments, dealing with the eggshells persisting after an infestation has been an onerous task for most households. This type of product can enable families to deal more easily with persistent eggshells and improve self-esteem in affected children. creator: Elizabeth R. Brunton creator: Ian P. Whelan creator: Rebecca French creator: Mark N. Burgess creator: Ian F. Burgess uri: https://doi.org/10.7717/peerj.6759 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2019 Brunton et al. title: Comparative characterization of biochars produced at three selected pyrolysis temperatures from common woody and herbaceous waste streams link: https://peerj.com/articles/6784 last-modified: 2019-04-15 description: Biochar, the product of biomass pyrolysis, has been explored as a soil amendment and carbon capture vessel. Recent literature has aligned biochar as a novel sorbent for a host of environmental contaminants. Through the variation of pyrolysis conditions, biochars can be engineered to have qualities desirable in sorbents whilst maintaining their agronomic benefits. This study focuses on identifying the effects that feedstock type and process temperature have on biochar characteristics which may in turn shed light on their potential environmental applications. Using this approach, six biochars were created from two waste biomasses. The biochars exhibited wide ranges of pH (5.6–11.1), surface area (16.2–397.4 m2/g), electrical conductivity (19–2,826 µS/cm), fixed carbon (72–97%), heavy metal and polycyclic aromatic hydrocarbons (PAHs). Statistically significant trends (P < 0.05) in biochar characteristics dependent upon increasing pyrolysis temperature and feedstock type were identified. Arsenic (>13 mg/kg), chromium (>93 mg/kg), copper (>143 mg/kg) and PAH (>6 mg/kg) concentrations presented themselves as obstacles to land application in a small number of biochars with respects to International Biochar Initiative (IBI) guidelines. However, it was demonstrated that these could be eliminated through employing pyrolysis processes which encompass higher temperatures (>500 °C) and ensuring the use of contaminant-free feedstocks. The variation in surface areas, carbonized fractions and surface functional groups achieved suggest that using the correct feedstock and process, biochar could be produced in Victoria (Australia) from common organic waste streams to the ends of acting as a sorbent, soil enhancer, and a waste management strategy. creator: Matthew Askeland creator: Bradley Clarke creator: Jorge Paz-Ferreiro uri: https://doi.org/10.7717/peerj.6784 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2019 Askeland et al. title: Marine biodiversity research in the Ryukyu Islands, Japan: current status and trends link: https://peerj.com/articles/6532 last-modified: 2019-04-12 description: Marine biodiversity and derived ecosystem services are critical to the healthy functioning of marine ecosystems, and to human economic and societal well-being. Thus, an understanding of marine biodiversity in different ecosystems is necessary for their conservation and management. Coral reefs in particular are noted for their high levels of biodiversity, and among the world’s coral reefs, the subtropical Ryukyu Islands (RYS; also known as the Nansei Islands) in Japan have been shown to harbor very high levels of marine biodiversity. This study provides an overview of the state of marine biodiversity research in the RYS. First, we examined the amount of English language scientific literature in the Web of Science (WoS; 1995–2017) on six selected representative taxa spanning protists to vertebrates across six geographic sub-regions in the RYS. Our results show clear taxonomic and sub-region bias, with research on Pisces, Cnidaria, and Crustacea to be much more common than on Dinoflagellata, Echinodermata, and Mollusca. Such research was more commonly conducted in sub-regions with larger human populations (Okinawa, Yaeyama). Additional analyses with the Ocean Biogeographic Information System (OBIS) records show that within sub-regions, records are concentrated in areas directly around marine research stations and institutes (if present), further showing geographical bias within sub-regions. While not surprising, the results indicate a need to address ‘understudied’ taxa in ‘understudied sub-regions’ (Tokara, Miyako, Yakutane, Amami Oshima), particularly sub-regions away from marine research stations. Second, we compared the numbers of English language scientific papers on eight ecological topics for the RYS with numbers from selected major coral reef regions of the world; the Caribbean (CAR), Great Barrier Reef (GBR), and the Red Sea (RES). As expected, the numbers for all topics in the RYS were well below numbers from all other regions, yet within this disparity, research in the RYS on ‘marine protected areas’ and ‘herbivory’ was an order of magnitude lower than numbers in other regions. Additionally, while manuscript numbers on the RYS have increased from 1995 to 2016, the rate of increase (4.0 times) was seen to be lower than those in the CAR, RES, and GBR (4.6–8.4 times). Coral reefs in the RYS feature high levels of both endemism and anthropogenic threats, and subsequently they contain a concentration of some of the world’s most critically endangered marine species. To protect these threatened species and coral reef ecosystems, more data are needed to fill the research gaps identified in this study. creator: James Davis Reimer creator: Piera Biondi creator: Yee Wah Lau creator: Giovanni Diego Masucci creator: Xuan Hoa Nguyen creator: Maria E.A. Santos creator: Hin Boo Wee uri: https://doi.org/10.7717/peerj.6532 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2019 Reimer et al. title: Do the regular annual extreme water level changes affect the seasonal appearance of Anabaena in Poyang Lake? link: https://peerj.com/articles/6608 last-modified: 2019-04-12 description: BackgroundPoyang Lake is an ecosystem experiencing annual variations in water level of up to 14 m. Water level changes were 8.03 and 11.22 m, respectively, in the years 2013 and 2014. The biomass and heterocyst frequency of Anabaena increased in the summers of recent years.MethodsA weekly to bi-weekly monitoring from June to November 2013 and 2014 was set up to explain the variations of Anabaena appearance in different phases of the water level.ResultsAnabaena was present in the lake throughout the year. The average relative biomass of Anabaena in the present study was over 40%, being most abundant in summer. The average heterocyst frequency was 0.23% in 2013 and 0.76% in 2014. Correlation analysis indicated a positive trend of Anabaena biomass with water temperature and water level and a negative one with total nitrogen (TN), which is the reason for the increase of heterocyst frequency in 2013 and 2014. Heterocyst frequency of Anabaena was positively correlated with water temperature, water level and PO4-P, and negatively with dissolved inorganic nitrogen (DIN/DIP), NO3-N and TN. Moreover, water temperature and DIN/DIP were significantly correlated with water level, indicating that water level changes have a direct effect on Anabaena and heterocyst formation in Poyang Lake.ConclusionsThe results of this study support the hypothesis that increasing biomass and heterocyst formation of Anabaena can be primarily caused by seasonal changes of the water level in Poyang Lake. creator: Kuimei Qian creator: Martin Dokulil creator: Yuwei Chen uri: https://doi.org/10.7717/peerj.6608 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2019 Qian et al. title: Comparison of long-term kidney functions after radical nephrectomy and simple nephrectomy link: https://peerj.com/articles/6701 last-modified: 2019-04-12 description: ObjectiveTo determine if there is a difference in proceeding to CKD between patients who had undergone radical nephrectomy (RN) and simple nephrectomy (SN) for different indications by comparing the short- and long-term renal function.Materials and MethodsWe retrospectively analyzed the records of all patients who underwent nephrectomy (either for malign or benign indications) in our clinic between January 2007 and September 2017. The patients were divided into 2 groups according the type of surgery: 1) Radical nephrectomy Group, 2) Simple Nephrectomy Group. Renal function was evaluated with Glomerular Filtration Rate (GFR) calculated using the MDRD formula.ResultsA total of 276 patients were included in the study. There were 202 patients in RN Group and 74 patients in SN Group. The mean age of the patients in RN Group and SN Group were age 59,2 ± 11,5 and 49,9 ± 15,1 years, respectively (p = 0.001). GFR levels of patients in RN Group versus SN Group were as follows: Preoperative period: 84.9 vs. 81 mL/min/1.73 m2; postoperative 1st day: 60.5 vs. 84.4 mL/min/1.73 m2, postoperative 1st month 58.9 vs. 76 mL/min/1.73 m2, postoperative 1st year: 59.5 vs. 74.1 mL/min/1.73 m2; at last control 60.3 and 76.1 mL/min/1.73 m2. While preoperative GFR was found to be similar in two groups (p = 0.26), postoperative GFR values were found to be significantly lower in Group RN (p < 0.001). In comparison of the decrease in GFR in two groups at last follow-up, significantly higher decrease was observed in RN Group, 29% vs. 6%, (p < 0.05).ConclusionThe decrease in GFR exists more common and intensive after RN compared to SN. In long-term, compensation mechanisms that develop after sudden nephron loss like radical nephrectomy deteriorates kidney function more than gradual nephron loss as in benign etiologies which indicates simple nephrectomy. creator: Erkan Olcucuoglu creator: Senol Tonyali creator: Sedat Tastemur creator: Yusuf Kasap creator: Mehmet Emin Sirin creator: Eymen Gazel creator: Esin Olcucuoglu creator: Oner Odabas creator: Can Ates creator: Mahmut Taha Olcucu uri: https://doi.org/10.7717/peerj.6701 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2019 Olcucuoglu et al. title: The prevalence of Pseudomonas aeruginosa and multidrug resistant Pseudomonas aeruginosa in healthy captive ophidian link: https://peerj.com/articles/6706 last-modified: 2019-04-12 description: BackgroundSnakes are globally considered as pet animals, and millions of ophidians are bred in captivity. Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium that can act as an opportunistic pathogen of man and animals and is frequently present in the oral and cloacal microbiota of healthy ophidians. It can cause severe clinical diseases and often shows antibiotic resistance. The aim of this study was to evaluate the prevalence and antibiotic resistance profiles of P. aeruginosa isolated from the cloacal microbiota of a large population sample of healthy captive ophidians and to evaluate the statistical associations with farming conditions.MethodsA total of 419 cloacal swabs were collected from snakes belonging to the Boidae (n = 45), Colubridae (n = 48) and Pythonidae (n = 326) families and inoculated onto complete culture media. Food, water and bedding samples were also analyzed. The antimicrobial susceptibility of P. aeruginosa isolates was evaluated through the Kirby-Bauer agar diffusion test. Statistical analyses were performed with the chi-square test.ResultsThe prevalence of P. aeruginosa was 59.9%, and 35.5% of these strains were multidrug resistant (MDR). The prevalence of MDR P. aeruginosa was significantly higher in adult samples than in young samples, and widespread resistance to Cephalosporins, Polymyxins and Sulfonamides was observed. Statistically significant differences in the prevalence of P. aeruginosa were observed depending on the farm size and snake family. Feeding thawed prey was associated with a higher P. aeruginosa and MDR P. aeruginosa prevalence. Moreover, snakes fed home-raised prey had a significantly higher MDR P. aeruginosa prevalence than snakes fed commercially available feed. Less frequent terrarium cleaning was associated with a higher MDR P. aeruginosa prevalence. On the other hand, snake reproductive status was not significantly associated with P. aeruginosa or MDR P. aeruginosa prevalence. All food, water and bedding samples were negative for P. aeruginosa presence.DiscussionThe overall P. aeruginosa prevalence found in this study was lower than that found by other authors, but a high proportion of the isolates were MDR. This study highlighted the presence of constitutive (such as age and taxonomic family) and managerial (farm size, cleaning cycle frequency and food type) factors associated with P. aeruginosa and/or MDR P. aeruginosa prevalence. Good breeding management and proper antibiotic treatment of P. aeruginosa infections could help reduce the presence of P. aeruginosa and MDR P. aeruginosa in the gut microbiota of snakes and consequently reduce the risk to public health. creator: Andrea Sala creator: Francesco Di Ianni creator: Igor Pelizzone creator: Mara Bertocchi creator: Davide Santospirito creator: Francesco Rogato creator: Sara Flisi creator: Costanza Spadini creator: Tiziano Iemmi creator: Emanuele Moggia creator: Enrico Parmigiani creator: Sandro Cavirani creator: Simone Taddei creator: Clotilde S. Cabassi uri: https://doi.org/10.7717/peerj.6706 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2019 Sala et al. title: Identification and differential expression of piRNAs in the gonads of Amur sturgeon (Acipenser schrenckii) link: https://peerj.com/articles/6709 last-modified: 2019-04-12 description: ObjectiveSturgeons are considered living fossils, and have a very high conservation and economic value. Studies on the molecular mechanism of sturgeon gonadal development and sex differentiation would not only aid in understanding vertebrate sex determination but also benefit sturgeon aquaculture. Piwi-interacting RNAs (piRNAs) have been shown to function in germline or gonadal development. In this study, we performed small RNA deep sequencing and microarray hybridization to identify potential sturgeon piRNAs.MethodsMale and female sturgeon gonads were collected and used for small RNA sequencing on an Illumina HiSeq platform with the validation of piRNA expression by microarray chip. The program Bowtie and k-mer scheme were performed to filter small RNA reads and discover potential sturgeon piRNAs. A known piRNA database, the coding sequence (CDS), 5′ and 3′ untranslated region (UTR) database of the A. Schrenckii transcriptome, Gene Ontology (GO) database and KEGG pathway database were searched subsequently to analyze the potential bio-function of sturgeon piRNAs.ResultsA total of 875,679 putative sturgeon piRNAs were obtained, including 93 homologous to known piRNAs and hundreds showing sex-specific and sex-biased expression. Further analysis showed that they are predominant in both the ovaries and testes and those with a sex-specific expression pattern are nearly equally distribution between sexes. This may imply a relevant role in sturgeon gonadal development. KEGG pathway and GO annotation analyses indicated that they may be related to sturgeon reproductive processes.ConclusionOur study provides the first insights into the gonadal piRNAs in a sturgeon species and should serve as a useful resource for further elucidation of the gene regulation involved in the sex differentiation of vertebrates. These results should also facilitate the technological development of early sex identification in sturgeon aquaculture. creator: Lihong Yuan creator: Linmiao Li creator: Xiujuan Zhang creator: Haiying Jiang creator: Jinping Chen uri: https://doi.org/10.7717/peerj.6709 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2019 Yuan et al. title: An experimental study on the early diagnosis of traumatic brain injury in rabbits based on a noncontact and portable system link: https://peerj.com/articles/6717 last-modified: 2019-04-12 description: Closed cerebral hemorrhage (CCH) is a common symptom in traumatic brain injury (TBI) patients who suffer intracranial hemorrhage with the dura mater remaining intact. The diagnosis of CCH patients prior to hospitalization and in the early stage of the disease can help patients get earlier treatments that improve outcomes. In this study, a noncontact, portable system for early TBI-induced CCH detection was constructed that measures the magnetic induction phase shift (MIPS), which is associated with the mean brain conductivity caused by the ratio between the liquid (blood/CSF and the intracranial tissues) change. To evaluate the performance of this system, a rabbit CCH model with two severity levels was established based on the horizontal biological impactor BIM-II, whose feasibility was verified by computed tomography images of three sections and three serial slices. There were two groups involved in the experiments (group 1 with 10 TBI rabbits were simulated by hammer hit with air pressure of 600 kPa by BIM-II and group 2 with 10 TBI rabbits were simulated with 650 kPa). The MIPS values of the two groups were obtained within 30 min before and after injury. In group 1, the MIPS values showed a constant downward trend with a minimum value of −11.17 ± 2.91° at the 30th min after 600 kPa impact by BIM-II. After the 650 kPa impact, the MIPS values in group 2 showed a constant downward trend until the 25th min, with a minimum value of −16.81 ± 2.10°. Unlike group 1, the MIPS values showed an upward trend after that point. Before the injury, the MIPS values in both group 1 and group 2 did not obviously change within the 30 min measurement. Using a support vector machine at the same time point after injury, the classification accuracy of the two types of severity was shown to be beyond 90%. Combined with CCH pathological mechanisms, this system can not only achieve the detection of early functional changes in CCH but can also distinguish different severities of CCH. creator: Jun Yang creator: Hui Zhao creator: Gen Li creator: Qisheng Ran creator: Jingbo Chen creator: Zelin Bai creator: Gui Jin creator: Jian Sun creator: Jia Xu creator: Mingxin Qin creator: Mingsheng Chen uri: https://doi.org/10.7717/peerj.6717 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2019 Yang et al. title: Upstream sequence-dependent suppression and AtxA-dependent activation of protective antigens in Bacillus anthracis link: https://peerj.com/articles/6718 last-modified: 2019-04-12 description: The anthrax toxin is a virulence factor produced by the bacterium Bacillus anthracis. Transcription of anthrax toxin genes is controlled by the transcription factor AtxA. Thus, AtxA is thought to be a key factor for the pathogenicity of B. anthracis. Despite its important role in B. anthracis infection, the molecular mechanism by which AtxA controls expression of anthrax toxin remains unclear. This study aimed to characterize the molecular mechanism of AtxA-mediated regulation of protective antigen (PA), a component of anthrax toxin encoded by the pagA gene. First, the interaction between the upstream region of pagA and AtxA was evaluated in vivo by constructing a transcriptional fusion of the upstream region with an auxotrophic marker. The results showed that (i) the upstream region of pagA suppressed transcription of the downstream gene and (ii) AtxA recovered suppressed transcription. Second, in vitro analysis using a gel mobility shift assay was performed to evaluate binding specificity of the AtxA–DNA interaction. The result showed sequence-independent binding of AtxA to DNA. Taken together, our findings suggest that the expression of PA was suppressed by the upstream region of pagA and that an interaction of AtxA and the upstream region releases the suppression. creator: Kochi Toyomane creator: Yoshikazu Furuta creator: Daisuke Fujikura creator: Hideaki Higashi uri: https://doi.org/10.7717/peerj.6718 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2019 Toyomane et al.