Assessment of the efficacy of using taurine supplements to improve growth and feed utilization of juvenile starry flounder (Platichthys stellatus) given diets based on soy-protein
A feeding trial was conducted to assess the feasibility of supplementing taurine in soy-based diets for juvenile starry flounder Platichthys stellatus. The basal diet (Crude protein 66.5%, crude lipid 8.5%) was supplemented with 0 (control), 0.5%, 1.0%, 1.5%, 2.0% and 2.5% taurine to formulate six test diets. Each diet was fed to 40 juvenile fish (22.25 g) in triplicate tanks (120 L) attached to a sea water circulation-system. Fish were fed twice daily by hand to apparent satiation during the 56-d trial. At the end of the trial, fish were counted and weighed for the analyses of growth performance, diet utilization and survival after a 24-h fast. Blood, intestines and muscles were collected for the analyses of serum oxidation resistance, digestive enzymes and body compostion. Livers were collected from the remaining fish at 4 h post-feeding for metabolic enzymes analyses. The results showed that fish fed diets supplemented with 1.0–2.5% taurine grew from 22.25–22.26 g to 47.88–50.40 g with higher average weight gain (25.62–28.12 vs 23.07 g ), specific growth rate (1.37–1.46 vs 1.27%/d ), feed intake (1.04–1.06 vs 1.00%/d), protein efficiency (2.50–2.61 vs 2.44) and lower feed conversion rate (0.84–0.83 vs 0.89) than the control treatment. Diets supplemented with 1.5–2.5% taurine significantly elevated the activities of pepsin (2.47–2.55 vs 2.22, U mg−1 prot), trypsin of distal intestine(14.55–15.24 vs 11.94, U mg−1 prot), hepatic glucokinase (126.62–129.42 vs 105.56, U mg−1 prot) and fatty acid synthetase (125.56-136.89 vs 108.45, U mg−1 prot). All diets supplemented with taurine increased the activities of lipase (32.23–36.67 vs 29.53, U g−1 prot) and trypsin (35.85–37.89 vs 33.54, U mg−1 prot) of proximal intestine, hepatic aspartate transaminase (736.990–832.38 vs 699.24, U mg−1 prot), alanine aminotransferase (477.40–551.86 vs 373.97, U mg−1 prot) and glycogen synthase (2.16–2.59 vs 1.97, U mg−1 prot), as well as serum superoxide dismutase (4.33–4.59 vs 4.07, U mg−1 prot ) and glutathione peroxidase (42.23–50.25 vs 39.17, mol mg−1 prot). Therefore, taurine supplementation benefits juvenile starry flounder growth, digestion, nutrients metabolism and oxidation resistance. The optimal taurine requirement for starry flounder is 1.75%, and the recommended supplementation level is at least 1.6% for maximizing growth of fish fed a low-fishmeal diet (13.6%).
Li et al. (2021) Assessment of the efficacy of using taurine supplements to improve growth and feed utilization of juvenile starry flounder (Platichthys stellatus) given diets based on soy-protein. PeerJ 9:e10597 https://doi.org/10.7717/peerj.10597
Associations between self-reported and objective face recognition abilities are only evident in above- and below-average recognisers
The 20-Item Prosopagnosia Items (PI-20) was recently introduced as a self-report measure of face recognition abilities and as an instrument to help the diagnosis of prosopagnosia. In general, studies using this questionnaire have shown that observers have moderate to strong insights into their face recognition abilities. However, it remains unknown whether these insights are equivalent for the whole range of face recognition abilities. The present study investigates this issue using the Mandarin version of the PI-20 and the Cambridge Face Memory Test Chinese (CFMT-Chinese). Our results showed a moderate negative association between the PI-20 and the CFMT-Chinese. However, this association was driven by people with low and high face recognition ability, but absent in people within the typical range of face recognition performance. The implications of these results for the study of individual differences and the diagnosis of prosopagnosia are discussed.
Estudillo et al. (2021) Associations between self-reported and objective face recognition abilities are only evident in above- and below-average recognisers. PeerJ 9:e10629 https://doi.org/10.7717/peerj.10629
The cause of deaths of 350 elephants in 2020 in a relatively small unprotected area of northern Botswana is unknown, and may never be known. Media speculations about it ignore ecological realities. Worse, they make conjectures that can be detrimental to wildlife and sometimes discredit conservation incentives. A broader understanding of the ecological and conservation issues speaks to elephant management across the Kavango–Zambezi Transfrontier Conservation Area that extends across Botswana, Namibia, Angola, Zambia, and Zimbabwe. Our communication addresses these. Malicious poisoning and poaching are unlikely to have played a role. Other species were unaffected, and elephant carcases had their tusks intact. Restriction of freshwater supplies that force elephants to use pans as a water source possibly polluted by blue-green algae blooms is a possible cause, but as yet not supported by evidence. No other species were involved. A contagious disease is the more probable one. Fences and a deep channel of water confine these elephants’ dispersal. These factors explain the elephants’ relatively high population growth rate despite a spell of increased poaching during 2014–2018. While the deaths represent only ~2% of the area’s elephants, the additive effects of poaching and stress induced by people protecting their crops cause alarm. Confinement and relatively high densities probably explain why the die-off occurred only here. It suggests a re-alignment or removal of fences that restrict elephant movements and limits year-round access to freshwater.
van Aarde et al. (2021) The 2020 elephant die-off in Botswana. PeerJ 9:e10686 https://doi.org/10.7717/peerj.10686
Silk derived formulations for accelerated wound healing in diabetic mice
Background The present study aimed to prepare effective silk derived formulations in combination with plant extract (Aloe vera gel) to speed up the wound healing process in diabetic mice. Methods Diabetes was induced in albino mice by using alloxan monohydrate. After successful induction of diabetes in mice, excision wounds were created via biopsy puncture (6 mm). Wound healing effect of silk sericin (5%) and silk fibroin (5%) individually and in combination with 5% Aloe vera gel was evaluated by determining the percent wound contraction, healing time and histological analysis. Results The results indicated that the best biocompatible silk combination was of 5% silk fibroin and 5% Aloe vera gel in which wounds were healed in 13 days with wound contraction: 98.33 ± 0.80%. In contrast, the wound of the control group (polyfax) healed in 19 day shaving 98.5 ± 0.67% contraction. Histological analysis revealed that the wounds which were treated with silk formulations exhibited an increased growth of blood vessels, collagen fibers, and much reduced inflammation. Conclusion It can be concluded that a combination of Bombyx mori silk and Aloe vera gel is a natural biomaterial that can be utilized in wound dressings and to prepare more innovative silk based formulations for speedy recovery of chronic wounds.
Tariq et al. (2021) Silk derived formulations for accelerated wound healing in diabetic mice. PeerJ 9:e10232 https://doi.org/10.7717/peerj.10232
Construction and validation of a novel prognostic signature of microRNAs in lung adenocarcinoma
MicroRNA (miRNA, miR) has been reported to be highly implicated in a wide range of biological processes in lung cancer (LC), and identification of differentially expressed miRNAs between normal and LC samples has been widely used in the discovery of prognostic factors for overall survival (OS) and response to therapy. The present study was designed to develop and evaluate a miRNA-based signature with prognostic value for the OS of lung adenocarcinoma (LUAD), a common histologic subtype of LC. In brief, the miRNA expression profiles and clinicopathological factors of 499 LUAD patients were collected from The Cancer Genome Atlas (TCGA) database. Kaplan–Meier (K-M) survival analysis showed significant correlations between differentially expressed miRNAs and LUAD survival outcomes. Afterward, 1,000 resample LUAD training matrices based on the training set was applied to identify the potential prognostic miRNAs. The least absolute shrinkage and selection operator (LASSO) cox regression analysis was used to constructed a six-miRNA based prognostic signature for LUAD patients. Samples with different risk scores displayed distinct OS in K-M analysis, indicating considerable predictive accuracy of this signature in both training and validation sets. Furthermore, time-dependent receiver operating characteristic (ROC) analysis demonstrated the nomogram achieved higher predictive accuracy than any other clinical variables after incorporating the clinical information (age, sex, stage, and recurrence). In the stratification analysis, the prognostic value of this classifier in LUAD patients was validated to be independent of other clinicopathological variables, such as age, gender, tumor recurrence, and early stage. Gene set annotation analyses were also conducted through the Hallmark gene set and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, indicating target genes of the six miRNAs were positively related to various molecular pathways of cancer, such as hallmark UV response, Wnt signaling pathway and mTOR signaling pathway. In addition, fresh cancer tissue samples and matched adjacent tissue samples from 12 LUAD patients were collected to verify the expression of miR-582’s target genes in the model, further revealing the potential relationship between SOX9, RASA1, CEP55, MAP4K4 and LUAD tumorigenesis, and validating the predictive value of the model. Taken together, the present study identified a robust signature for the OS prediction of LUAD patients, which could potentially aid in the individualized selection of therapeutic approaches for LUAD patients.
Li et al. (2021) Construction and validation of a novel prognostic signature of microRNAs in lung adenocarcinoma. PeerJ 9:e10470 https://doi.org/10.7717/peerj.10470
Perfluorooctane sulfonate exerts inflammatory bowel disease-like intestinal injury in rats
Background Perfluorooctane sulfonate (PFOS), a type of perfluorinated compounds (PFCs), can induce various organ toxicity, including hepatomegaly, immunotoxicity, and gut microbiota disorder. PFCs have been associated with inflammatory bowel disease (IBD). Yet, whether PFOS exposure causes IBD-like disorder and the underlying mechanism remains undefined. Here, we investigated the influence of PFOS exposure on the development of IBD-like disorder in rats. Methods Sprague-Dawley rats were intraperitoneally injected with PFOS (1 or 10 mg/kg) or normal saline (NS) every other day for 15 days. Body weight, serum concentrations of serum amyloid A (SAA) and high sensitivity C reactive protein (hsCRP) were measured. Pathological assessments of villi height and crypt depth in the proximal duodenum and jejunum were performed using H&E staining. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was used to assay cell apoptosis in the jejunum. The infiltration of inflammatory cells and cytokines in the jejunum were detected by immunohistochemistry analysis. Results PFOS (10 mg/kg) significantly increased the body weight, SAA and hsCRP, whereas no significant differences were observed in PFOS 1 mg/kg group of rats. The villi height and crypt depth in the proximal duodenum and jejunum were significantly reduced upon PFOS exposure. PFOS induced higher histopathological score in intestinal tissues compared to NS. Notably, TUNEL-positive cells were significantly higher in the jejunum upon PFOS exposure. Further, neutrophil and macrophage accumulated, and inflammatory cytokines infiltration were also remarkably increased in rats exposed to PFOS. Conclusion PFOS induces IBD-like phenotypes in rats, with associated inflammatory infiltration to intestinal.
Liang et al. (2021) Perfluorooctane sulfonate exerts inflammatory bowel disease-like intestinal injury in rats. PeerJ 9:e10644 https://doi.org/10.7717/peerj.10644
Microbial community structure in aquifers associated with arsenic: analysis of 16S rRNA and arsenite oxidase genes
The microbiomes of deep and shallow aquifers located in an agricultural area, impacted by an old tin mine, were explored to understand spatial variation in microbial community structures and identify environmental factors influencing microbial distribution patterns through the analysis of 16S rRNA and aioA genes. Although Proteobacteria, Cyanobacteria, Actinobacteria, Patescibacteria, Bacteroidetes, and Epsilonbacteraeota were widespread across the analyzed aquifers, the dominant taxa found in each aquifer were unique. The co-dominance of Burkholderiaceae and Gallionellaceae potentially controlled arsenic immobilization in the aquifers. Analysis of the aioA gene suggested that arsenite-oxidizing bacteria phylogenetically associated with Alpha-, Beta-, and Gamma proteobacteria were present at low abundance (0.85 to 37.13%) and were more prevalent in shallow aquifers and surface water. The concentrations of dissolved oxygen and total phosphorus significantly governed the microbiomes analyzed in this study, while the combination of NO3--N concentration and oxidation-reduction potential significantly influenced the diversity and abundance of arsenite-oxidizing bacteria in the aquifers. The knowledge of microbial community structures and functions in relation to deep and shallow aquifers is required for further development of sustainable aquifer management.
Environmental Contamination and Remediation
Sonthiphand et al. (2021) Microbial community structure in aquifers associated with arsenic: analysis of 16S rRNA and arsenite oxidase genes. PeerJ 9:e10653 https://doi.org/10.7717/peerj.10653
DNA profiling and assessment of genetic diversity of relict species Allium altaicum Pall. on the territory of Altai
Analysis of the genetic diversity of natural populations of threatened and endangered species of plants is a main aspect of conservation strategy. The endangered species Allium altaicum is a relict plant of the Ice Age and natural populations are located in extreme climatic conditions of Kazakstan’s Altai Mountains. Mobile genetic elements and other interspersed repeats are basic components of a eukaryote genome, which can activate under stress conditions and indirectly promote the survival of an organism against environmental stresses. Detections of chromosomal changes related to recombination processes of mobile genetic elements are performed by various PCR methods. These methods are based on interspersed repeat sequences and are an effective tool for research of biological diversity of plants and their variability. In our research, we used conservative sequences of tRNA primer binding sites (PBS) when initializing the retrotransposon replication as PCR primers to research the genetic diversity of 12 natural populations of A. altaicum found in various ecogeographic conditions of the Kazakhstani Altai. High efficiency of the PBS amplification method used was observed already at the intrapopulation level. Unique amplicons representative of a certain population were found at the intrapopulation level. Analysis of molecular dispersion revealed that the biodiversity of populations of mountainous and lowland A. altaicum is due to intrapopulation differences for climatic zones of habitation. This is likely conditional upon predominance of vegetative reproduction over seed reproduction in some populations. In the case of vegetative reproduction, somatic recombination related to the activity of mobile genetic elements are preserved in subsequent generations. This leads to an increase of intrapopulation genetic diversity. Thus, high genetic diversity was observed in populations such as A. altaicum located in the territory of the Kalbinskii Altai, whereas the minimum diversity was observed in the populations of the Leninororsk ecogeographic group. Distinctions between these populations were also identified depending on the areas of their distribution. Low-land and mid-mountain living environments are characterized by a great variety of shapes and plasticity. This work allowed us to obtain new genetic data on the structure of A. altaicum populations on the territory of the Kazakhstan Altai for the subsequent development of preservation and reproduction strategies for this relict species.
Khapilina et al. (2021) DNA profiling and assessment of genetic diversity of relict species Allium altaicum Pall. on the territory of Altai. PeerJ 9:e10674 https://doi.org/10.7717/peerj.10674
Synergism between calcium nitrate applications and fungal endophytes to increase sugar concentration in Festuca sinensis under cold stress
Epichloë endophytes have been shown to increase tolerance to biotic and abiotic stresses in many cool-season grasses. We investigated the impact of endophyte infection of Festuca sinensis, on root metabolic activity, photosynthetic pigments, leaf relative water content (RWC) and soluble carbohydrates in a field experiment carried out during chilling and irrigation with Ca(NO3)2. A highly significant (P < 0.001) correlation for Epichloë endophytes was observed for root metabolic activity. Ca(NO3)2 affected very significantly root metabolic activity and total chlorophyll (P < 0.001). Low temperature led to highly significant (P < 0.001) reductions in root metabolic activity, RWC, total chlorophyll, chlorophyll a/b ratio, and carotenoid contents. In addition, the fructose concentrations of shoots were greater on the 14th day than on the 28th day and before treatment, whilst the glucose concentration of roots was much higher on the 28th day than before and after 14 days treatment. Moreover, our results indicated that the addition of calcium nitrate contributed to higher levels of total chlorophylls, soluble sugars, sucrose, fructose or glucose in the shoots and roots in both E+ and E- plants during long periods of chilling. These results suggest that Epichloë endophyte infection and/or exogenous calcium nitrate can confer better tolerance to cold stress.
Zhou et al. (2021) Synergism between calcium nitrate applications and fungal endophytes to increase sugar concentration in Festuca sinensis under cold stress. PeerJ 9:e10568 https://doi.org/10.7717/peerj.10568
Strategies for recovery of imbalanced full-scale biogas reactor feeding with palm oil mill effluent
Background Full-scale biogas production from palm oil mill effluent (POME) was inhibited by low pH and highly volatile fatty acid (VFA) accumulation. Three strategies were investigated for recovering the anaerobic digestion (AD) imbalance on biogas production, namely the dilution method (tap water vs. biogas effluent), pH adjustment method (NaOH, NaHCO3, Ca(OH)2, oil palm ash), and bioaugmentation (active methane-producing sludge) method. The highly economical and feasible method was selected and validated in a full-scale application. Results The inhibited sludge from a full-scale biogas reactor could be recovered within 30–36 days by employing various strategies. Dilution of the inhibited sludge with biogas effluent at a ratio of 8:2, pH adjustment with 0.14% w/v NaOH, and 8.0% w/v oil palm ash were considered to be more economically feasible than other strategies tested (dilution with tap water, or pH adjustment with 0.50% w/v Ca(OH)2, or 1.25% NaHCO3 and bioaugmentation) with a recovery time of 30–36 days. The recovered biogas reactor exhibited a 35–83% higher methane yield than self-recovery, with a significantly increased hydrolysis constant (kH) and specific methanogenic activity (SMA). The population of Clostridium sp., Bacillus sp., and Methanosarcina sp. increased in the recovered sludge. The imbalanced full-scale hybrid cover lagoon reactor was recovered within 15 days by dilution with biogas effluent at a ratio of 8:2 and a better result than the lab-scale test (36 days). Conclusion Dilution of the inhibited sludge with biogas effluent could recover the imbalance of the full-scale POME-biogas reactor with economically feasible and high biogas production performance.
Wongfaed et al. (2021) Strategies for recovery of imbalanced full-scale biogas reactor feeding with palm oil mill effluent. PeerJ 9:e10592 https://doi.org/10.7717/peerj.10592