title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=737 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: Increased cortisol levels caused by acute resistance physical exercise impair memory and learning ability link: https://peerj.com/articles/13000 last-modified: 2022-03-23 description: Acute physical exercise works as an activator of the responses of the human organism to stress. This is based on the activation of the hypothalamic–pituitary–adrenal (HPA) axis, affecting physical, physiological and psychological levels. This study aimed to analyse the effects of a single bout of high-intensity resistance exercise on cognitive-behavioural responses: visuo-spatial path learning and memory, as well as physiological responses (salivary cortisol levels). Nineteen healthy male military-trained powerlifting subjects were tested in a within-subject design on two experimental days with an interval of 48 h. The stress and cognitive variables were measured by cortisol levels and Ruff–Light trail-learning test (RULIT) test scores, respectively. The results showed the immediate influence of acute exercise on cortisol, with significantly higher cortisol levels found in subjects after completion of the acute resistance exercise. In addition, this study found a significant deterioration of memory and learning ability after a dose of intense resistance exercise. In conclusion, the study highlights the relative effects of resistance exercise on cortisol and cognitive performance depending on the intensity and type of the exercise, the moment of measurement and the cerebral areas implicated. creator: José-Luis Bermejo creator: Raúl Valldecabres creator: Israel Villarrasa-Sapiña creator: Gonzalo Monfort-Torres creator: Adrià Marco-Ahulló creator: Bruno Ribeiro Do Couto uri: https://doi.org/10.7717/peerj.13000 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Bermejo et al. title: Antioxidant defense system in the prefrontal cortex of chronically stressed rats treated with lithium link: https://peerj.com/articles/13020 last-modified: 2022-03-23 description: BackgroundThis study aimed to investigate the effects of lithium treatment on gene expression and activity of the prefrontal antioxidant enzymes: copper, zinc superoxide dismutase (SOD1), manganes superoxide dismutase (SOD2), catalase (CAT), and glutathione peroxidase (GPx) in animals exposed to chronic restraint stress (CRS).MethodsThe investigated parameters were quantified using real-time RT-PCR, Western blot analyses, and assays of enzyme activities.ResultsWe found that lithium treatment decreased gene expression of SOD2, as well as the activities of SOD1 and SOD2 in chronically stressed rats to the levels found in unstressed animals. However, lithium treatment in animals exposed to CRS increased prefrontal GPx activity to the levels found in unstressed animals.ConclusionsThese findings confirm that treatment with lithium induced the modulation of prefrontal antioxidant status in chronically stressed rats. Our results may be very important in biomedical research for understanding the role of lithium in maintaining the stability of prefrontal antioxidant defense system in neuropsychiatric disorders caused by chronic stress. creator: Ljubica Gavrilović creator: Nataša Popović creator: Vesna Stojiljković creator: Snežana Pejić creator: Ana Todorović creator: Predrag Vujović creator: Snežana B. Pajović uri: https://doi.org/10.7717/peerj.13020 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Gavrilović et al. title: Exploring the genome of Lactobacillaceae spp. Sy-1 isolated from Heterotrigona itama honey link: https://peerj.com/articles/13053 last-modified: 2022-03-23 description: BackgroundHoney produced by Heterotrigona itama is highly preferred among consumers due to its high-value as a functional food and beneficial lactic acid bacteria (LAB) reservoir. Fructophilic lactic acid bacteria (FLAB) are a group of LAB with unique growth characteristics and are regarded as promising producers of bioactive compounds. Hence, it is not surprising that LAB, especially FLAB, may be involved with the excellent bioactivity of H. itama honey. With the trending consumer preference for H. itama honey coupled with increasing awareness for healthy food, the genomic background of FLAB isolated from this honey must, therefore, be clearly understood. In this study, one FLAB strain designated as Sy-1 was isolated from freshly collected H. itama honey. Its FLAB behavior and genomic features were investigated to uncover functional genes that could add value to functional food.MethodsThe fructophilic characteristics of strain Sy-1 were determined, and the genome was sequenced using Illumina iSeq100 and Oxford Nanopore. The average nucleotide identity and phylogenetic analyses based on 16S rRNA, 92 core genes, and whole-genome sequence were performed to unravel the phylogenetic position of strain Sy-1. NCBI Prokaryotic Genome Annotation Pipeline annotated the genome, while the EggNOG-mapper, BLASTKoala, and GHOSTKoala were used to add functional genes and pathways information.ResultsStrain Sy-1 prefers D-fructose over D-glucose and actively metabolizes D-glucose in the presence of electron acceptors. Genomic annotation of strain Sy-1 revealed few genes involved in carbohydrate transport and metabolism, and partial deletion of adhE gene, in line with the characteristic of FLAB. The 16S rRNA gene sequence of strain Sy-1 showed the highest similarity to unknown LAB species isolated from the gut of honeybees. The phylogenetic analyses discovered that strain Sy-1 belonged to the Lactobacillaceae family and formed a separate branch closer to type strain from the genera of Acetilactobacillus and Apilactobacillus. The ANI analysis showed the similarity of the closest relative, Apilactobacillus micheneri Hlig3T. The assembled genome of Sy-1 contains 3 contigs with 2.03 Mbp and a 41% GC content. A total of 1,785 genes were identified, including 1,685 protein-coding genes, 68 tRNA, and 15 rRNA. Interestingly, strain Sy-1 encoded complete genes for the biosynthesis of folate and riboflavin. High-performance liquid chromatography analysis further confirmed the high production of folic acid (1.346 mg/L) by Sy-1.DiscussionBased on phylogenetic and biochemical characteristics, strain Sy-1 should be classified as a novel genus in the family of Lactobacillaceae and a new member of FLAB. The genome information coupled with experimental studies supported the ability of strain Sy-1 to produce high folic acid. Our collective findings support the suitable application of FLAB strain Sy-1 in the functional food and pharmaceutical industries. creator: Syariffah Nuratiqah Syed Yaacob creator: Fahrul Huyop creator: Mailin Misson creator: Roswanira Abdul Wahab creator: Nurul Huda uri: https://doi.org/10.7717/peerj.13053 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Syed Yaacob et al. title: Metagenomic investigation of the equine faecal microbiome reveals extensive taxonomic diversity link: https://peerj.com/articles/13084 last-modified: 2022-03-23 description: BackgroundThe horse plays crucial roles across the globe, including in horseracing, as a working and companion animal and as a food animal. The horse hindgut microbiome makes a key contribution in turning a high fibre diet into body mass and horsepower. However, despite its importance, the horse hindgut microbiome remains largely undefined. Here, we applied culture-independent shotgun metagenomics to thoroughbred equine faecal samples to deliver novel insights into this complex microbial community.ResultsWe performed metagenomic sequencing on five equine faecal samples to construct 123 high- or medium-quality metagenome-assembled genomes from Bacteria and Archaea. In addition, we recovered nearly 200 bacteriophage genomes. We document surprising taxonomic diversity, encompassing dozens of novel or unnamed bacterial genera and species, to which we have assigned new Candidatus names. Many of these genera are conserved across a range of mammalian gut microbiomes.ConclusionsOur metagenomic analyses provide new insights into the bacterial, archaeal and bacteriophage components of the horse gut microbiome. The resulting datasets provide a key resource for future high-resolution taxonomic and functional studies on the equine gut microbiome. creator: Rachel Gilroy creator: Joy Leng creator: Anuradha Ravi creator: Evelien M. Adriaenssens creator: Aharon Oren creator: Dave Baker creator: Roberto M. La Ragione creator: Christopher Proudman creator: Mark J. Pallen uri: https://doi.org/10.7717/peerj.13084 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Gilroy et al. title: Reference values for bone density and bone mineral content from 5 to 80 years old in a province of Chile link: https://peerj.com/articles/13092 last-modified: 2022-03-23 description: BackgroundThe assessment of bone health throughout the life cycle is essential to determine fracture risk. The objectives of the work were (a) compare bone mineral density and content with international references from the United States, (b) determine maximum bone mass, (c) propose references for bone health measurements from ages 5 to 80 years old.MethodsResearch was carried out on 5,416 subjects. Weight and height were measured. Body Mass Index (BMI) was calculated. The total body was scanned using dual energy X-ray absorptiometry (DXA). Information was extracted from the bone health measures (bone mineral density (BMD) and bone mineral content (BMC)) for both sexes, according to pediatric and adult software.Results and DiscussionDifferences were identified between the mean values of Chilean and American men for BMD (~0.03 to 0.11 g/cm2) and BMC (~0.15 to 0.46 g). Chilean females showed average values for BMD similar to the US references (~−0.01 to 0.02 g/cm2). At the same time, they were relatively higher for BMC (~0.07 to 0.33 g). The cubic polynomial regression model reflected a relationship between BMD and BMC with chronological age in both sexes. For males, R2 was higher (R2 = 0.72 and 0.75) than for females (R2 = 0.59 and 0.66). The estimate of maximum bone mass (MBM) for males emerged at 30 years old (1.45 ± 0.18 g/cm2 of BMD and 3.57 ± 0.60 g of BMC) and for females at age 28 (1.22 ± 0.13 g/cm2 of BMD and 2.57 ± 0.44 g of BMC). The LMS technique was used to generate smoothed percentiles for BMD and BMC by age and sex. Results showed that maximum bone mass occurred in females at age 28 and in males at 30. Reference values obtained from this research may be used to evaluate bone health, diagnose bone fragility and osteoporosis in individuals and regional population groups. creator: Marco Cossio-Bolanos creator: Rubén Vidal-Espinoza creator: Jose Fuentes-Lopez creator: Luis Felipe Castelli Correia de Campos creator: Cynthia Lee Andruske creator: Camilo Urra-Albornoz creator: Fernando Alvear Vasquez creator: Rossana Gomez-Campos uri: https://doi.org/10.7717/peerj.13092 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Cossio-Bolanos et al. title: A flexible and accurate method for electroencephalography rhythms extraction based on circulant singular spectrum analysis link: https://peerj.com/articles/13096 last-modified: 2022-03-23 description: Rhythms extraction from electroencephalography (EEG) signals can be used to monitor the physiological and pathological states of the brain and has attracted much attention in recent studies. A flexible and accurate method for EEG rhythms extraction was proposed by incorporating a novel circulant singular spectrum analysis (CiSSA). The EEG signals are decomposed into the sum of a set of orthogonal reconstructed components (RCs) at known frequencies. The frequency bandwidth of each RC is limited to a particular brain rhythm band, with no frequency mixing between different RCs. The RCs are then grouped flexibly to extract the desired EEG rhythms based on the known frequencies. The extracted brain rhythms are accurate and no mixed components of other rhythms or artifacts are included. Simulated EEG data based on the Markov Process Amplitude EEG model and experimental EEG data in the eyes-open and eyes-closed states were used to verify the CiSSA-based method. The results showed that the CiSSA-based method is flexible in alpha rhythms extraction and has a higher accuracy in distinguishing between the eyes-open and eyes-closed states, compared with the basic SSA method, the wavelet decomposition method, and the finite impulse response filtering method. creator: Hai Hu creator: Zihang Pu creator: Peng Wang uri: https://doi.org/10.7717/peerj.13096 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Hu et al. title: Growth and survival among Hawaiian corals outplanted from tanks to an ocean nursery are driven by individual genotype and species differences rather than preconditioning to thermal stress link: https://peerj.com/articles/13112 last-modified: 2022-03-23 description: The drastic decline in coral coverage has stimulated an interest in reef restoration, and various iterations of coral nurseries have been used to augment restoration strategies. Here we examine the growth of two species of Hawaiian Montipora that were maintained in mesocosms under either ambient or warmed annual bleaching conditions for two consecutive years prior to outplanting to determine whether preconditioning aided coral restoration efforts. Using coral trees to create a nearby ocean nursery, we examined whether: (1) previous ex situ mesocosm growth would mirror in situ coral tree nursery growth; and (2) thermal ex situ stress-hardening would predict future success during natural warming events in situ for corals moved from tanks to trees. For Montipora capitata, we found that variation in growth was explained primarily by genotype; growth rates in the mesocosms were similar to those in situ, irrespective of preconditioning. Variation in M. flabellata growth, however, was explained by both genotype and culture method such that an individual M. flabellata colony that grew well in the tanks did not necessarily perform as well on the coral trees. For both species, previous exposure to elevated temperatures in the mesocosms provided no benefit to either growth or survival during a warming event in the coral tree nursery compared to those grown in ambient temperatures. Overall, M. capitata performed better in the tree nursery with higher net growth, lower mortality, and was subject to less predation than M. flabellata. Our results show little benefit of the additional cost and time of stress-hardening these corals prior to outplanting because it is unlikely to aid resilience to future warming events. These results also suggest that selecting corals for restoration based on long-term genotype growth performance may be more effective for optimal outcomes but should be weighed against other factors, such as coral morphology, in situ nursery method, location, and other characteristics. creator: E. Michael Henley creator: Jessica Bouwmeester creator: Christopher P. Jury creator: Robert J. Toonen creator: Mariko Quinn creator: Claire V.A. Lager creator: Mary Hagedorn uri: https://doi.org/10.7717/peerj.13112 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Henley et al. title: Multilingual validation of the short form of the Unesp-Botucatu Feline Pain Scale (UFEPS-SF) link: https://peerj.com/articles/13134 last-modified: 2022-03-23 description: BackgroundPain is the leading cause of animal suffering, hence the importance of validated tools to ensure its appropriate evaluation and treatment. We aimed to test the psychometric properties of the short form of the Unesp-Botucatu Feline Pain Scale (UFEPS-SF) in eight languages.MethodsThe original scale was condensed from ten to four items. The content validation was performed by five specialists in veterinary anesthesia and analgesia. The English version of the scale was translated and back-translated into Chinese, French, German, Italian, Japanese, Portuguese and Spanish by fluent English and native speaker translators. Videos of the perioperative period of 30 cats submitted to ovariohysterectomy (preoperative, after surgery, after rescue analgesia and 24 h after surgery) were randomly evaluated twice (one-month interval) by one evaluator for each language unaware of the pain condition. After watching each video, the evaluators scored the unidimensional, UFEPS-SF and Glasgow composite multidimensional feline pain scales. Statistical analyses were carried out using R software for intra and interobserver reliability, principal component analysis, criteria concurrent and predictive validities, construct validity, item-total correlation, internal consistency, specificity, sensitivity, the definition of the intervention score for rescue analgesia and diagnostic uncertainty zone, according to the receiver operating characteristic (ROC) curve.ResultsUFEPS-SF intra- and inter-observer reliability were ≥0.92 and 0.84, respectively, for all observers. According to the principal component analysis, UFEPS-SF is a unidimensional scale. Concurrent criterion validity was confirmed by the high correlation between UFEPS-SF and all other scales (≥0.9). The total score and all items of UFEPS-SF increased after surgery (pain), decreased to baseline after analgesia and were intermediate at 24 h after surgery (moderate pain), confirming responsiveness and construct validity. Item total correlation of each item (0.68–0.83) confirmed that the items contributed homogeneously to the total score. Internal consistency was excellent (≥0.9) for all items. Both specificity (baseline) and sensitivity (after surgery) based on the Youden index was 99% (97–100%). The suggestive cut-off score for the administration of analgesia according to the ROC curve was ≥4 out of 12. The diagnostic uncertainty zone ranged from 3 to 4. The area under the curve of 0.99 indicated excellent discriminatory capacity of UFEPS-SF.ConclusionsThe UFEPS-SF and its items, assessed by experienced evaluators, demonstrated very good repeatability and reproducibility, content, criterion and construct validities, item-total correlation, internal consistency, excellent sensitivity and specificity and a cut-off point indicating the need for rescue analgesia in Chinese, French, English, German, Italian, Japanese, Portuguese and Spanish. creator: Stelio P.L. Luna creator: Pedro H.E. Trindade creator: Beatriz P. Monteiro creator: Nadia Crosignani creator: Giorgia della Rocca creator: Helene L.M. Ruel creator: Kazuto Yamashita creator: Peter Kronen creator: Chia Te Tseng creator: Lívia Teixeira creator: Paulo V. Steagall uri: https://doi.org/10.7717/peerj.13134 license: https://creativecommons.org/licenses/by/4.0/ rights: ©2022 Luna et al. title: Knowledge, attitudes and perceptions regarding human papillomavirus among university students in Hail, Saudi Arabia link: https://peerj.com/articles/13140 last-modified: 2022-03-23 description: BackgroundHuman papillomavirus (HPV) is a well-known cause of cervical cancer. The prevalence of HPV, insufficient preventive services, inadequate treatment access, socioeconomic conditions, certain cultural causes and values and opinions regarding cervical cancer have been established as factors contributing to the occurrence of cervical cancer in various parts of the world.ObjectiveTo determine university students’ knowledge, attitudes and perceptions regarding HPV and its vaccine.Material and MethodsThe present cross-sectional study included students enrolled at the University of Hail, Saudi Arabia. Data were collected from January to May 2020 using a previously validated 26-item questionnaire.ResultsA total of 386 participants responded to the survey; the response rate was 80%. The majority of the respondents (63%) were male and 332 (86%) respondents were single among the overall study population. Most respondents were aged 21–25 years (75.6%), followed by 26–30 years (12.7%). In total, 130 (33.7%) respondents reported that they had heard of HPV before, while 174 (45.1%) reported that HPV infections are rare in Saudi Arabia. Furthermore, 102 (26.4%) respondents thought that HPV causes genital warts, while almost 29.5% believed that HPV infection is a sexually transmitted disease. Nearly 76.2% of the respondents did not believe that HPV infection can occur without symptoms. Moreover, 53.4% of the respondents stated that they did not know the health problems associated with HPV infection, while 148 (38.8%) stated that cervical cancer is a health problem associated with HPV infection. When asked about their understanding of the HPV vaccine, nearly 267 (62.2%) respondents believed that there is no vaccine for HPV, while 239 (61.9%) believed that the vaccine does not minimise the risk of cervical cancer. In addition, the respondents reported that they would be far more likely to get an HPV vaccine if recommended by their doctors [relative importance index (RII) = 0.745], followed by their friends (RII = 0.675).ConclusionThe present findings provide a clear understanding of university students’ knowledge, perceptions and attitudes regarding HPV; this information can be used to raise awareness by developing an effective educational strategy. However, further research with a larger sample size is recommended; such efforts would also aid in the development of educational services for various age ranges. creator: Farhan Alshammari creator: Kashif Ullah Khan uri: https://doi.org/10.7717/peerj.13140 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Alshammari and Khan title: RapidHRV: an open-source toolbox for extracting heart rate and heart rate variability link: https://peerj.com/articles/13147 last-modified: 2022-03-23 description: Heart rate and heart rate variability have enabled insight into a myriad of psychophysiological phenomena. There is now an influx of research attempting using these metrics within both laboratory settings (typically derived through electrocardiography or pulse oximetry) and ecologically-rich contexts (via wearable photoplethysmography, i.e., smartwatches). However, these signals can be prone to artifacts and a low signal to noise ratio, which traditionally are detected and removed through visual inspection. Here, we developed an open-source Python package, RapidHRV, dedicated to the preprocessing, analysis, and visualization of heart rate and heart rate variability. Each of these modules can be executed with one line of code and includes automated cleaning. In simulated data, RapidHRV demonstrated excellent recovery of heart rate across most levels of noise (>=10 dB) and moderate-to-excellent recovery of heart rate variability even at relatively low signal to noise ratios (>=20 dB) and sampling rates (>=20 Hz). Validation in real datasets shows good-to-excellent recovery of heart rate and heart rate variability in electrocardiography and finger photoplethysmography recordings. Validation in wrist photoplethysmography demonstrated RapidHRV estimations were sensitive to heart rate and its variability under low motion conditions, but estimates were less stable under higher movement settings. creator: Peter A. Kirk creator: Alexander Davidson Bryan creator: Sarah N. Garfinkel creator: Oliver J. Robinson uri: https://doi.org/10.7717/peerj.13147 license: https://creativecommons.org/licenses/by/4.0/ rights: © 2022 Kirk et al.