Forest fragmentation causes an isolated population of the golden takin (Budorcas taxicolor bedfordi Thomas, 1911) (Artiodactyla: Bovidae) in the Qinling Mountains (China).

Budorcas taxicolor bedfordi is a rare animal uniquely distributed in the Qinling Mountains (China). Human disturbance and habitat fragmentation have directly affected the survival of B. t. bedfordi. It is urgent to clarify the genetic diversity and genetic structure of the B. t. bedfordi population and implement effective conservation measures. In this study, 20 new polymorphic microsatellite loci were isolated by Illumina sequencing. The genetic diversity and population structure of 124 B. t. bedfordi individuals from three populations (Niubeliang population, Zhouzhi population, and Foping population) were analysed according to these 20 microsatellite loci. Our results indicated that B. t. bedfordi had a low level of genetic variability and that there was inbreeding in the three populations. The population genetic structure analyses showed that the Niubeliang population had a trend of differentiation from other populations. National roads can affect population dispersal, while ecological corridors can promote population gene exchange. None of the three B. t. bedfordi populations experienced bottleneck effects. For conservation management plans, the Zhouzhi population and Foping population should be considered one management unit, and the Niubeliang population should be considered another management unit. We suggest building an ecological corridor to keep the habitat connected and formulating tourism management measures to reduce the influence of human disturbance on B. t. bedfordi.

Facile synthesis of phosphorus and nitrogen co-doped carbon dots with excellent fluorescence emission towards cellular imaging.

Fluorescent carbon nanomaterials have attracted increasing attention owing to their unique photoluminescence properties, good biocompatibility and low toxicity in bioimaging as well as biosensing. Heteroatom doping is usually used to improve photoluminescence properties by tuning the functional groups and the particle size domain effect, thus leading to redshifted emission. Here, we report a straightforward strategy for the fabrication of a mixture of fluorescent phosphorus and nitrogen carbon nanodots (P,N-CDs) followed by separating two kinds of fluorescent fractions based on their different negative charges. Such a one-pot hydrothermal method using formamide, urea and hydroxyethylidene diphosphonic acid as the precursor yields fluorescent P,N-CDs. Specifically, blue-emitting CDs (bCDs) and green-emitting CDs (gCDs) were separated by using column chromatography. The quantum yields of bCDs and gCDs were 20.33% and 1.92%, respectively. And the fluorescence lifetimes of bCDs and gCDs were 6.194 ns and 2.09 ns, respectively. What is more, the resultant P,N-CDs exhibited low toxicity and excellent biocompatibility. Confocal fluorescence microscopy images were obtained successfully, suggesting that P,N-CDs have excellent cell membrane permeability and cellular imaging. This work provides a promising fluorescent carbon nanomaterial with tunable emission as a probe for versatile applications in bioimaging, sensing and drug delivery.

Effects of Starvation and Refeeding on Growth, Digestion, Nonspecific Immunity and Lipid-Metabolism-Related Genes in Onychostoma macrolepis.

The present research was conducted to assess the influences of starvation and refeeding on growth, nonspecific immunity and lipid metabolic adaptation in Onychostoma macrolepis. To date, there have been no similar reports in O. macrolepis. The fish were randomly assigned into two groups: control group (continuous feeding for six weeks) and starved-refed group (starvation for three weeks and then refeeding for three weeks). After three weeks of starvation, the results showed that the body weight (BW, 1.44 g), condition factor (CF, 1.17%), visceral index (VSI, 3.96%), hepatopancreas index (HSI, 0.93%) and intraperitoneal fat index (IPFI, 0.70%) of fish were significantly lower compared to the control group (BW, 5.72 g; CF, 1.85%; VSI, 6.35%; HSI, 2.04%; IPFI, 1.92%) (p < 0.05). After starvation, the serum triglyceride (TG, 0.83 mmol/L), total cholesterol (T-GHOL, 1.15 mmol/L), high-density lipoprotein (HDL, 1.13 mmol/L) and low-density lipoprotein (LDL, 0.46 mmol/L) concentrations were significantly lower than those in the control group (TG, 1.69 mmol/L; T-GHOL, 1.86 mmol/L; HDL, 1.62 mmol/L; LDL, 0.63 mmol/L) (p < 0.05). The activities of intestinal digestive enzymes (amylase, lipase and protease) in the starved-refed group were significantly lower than those in the control group after three weeks of starvation (p < 0.05). The highest activities of immune enzymes such as lysozyme (LZM), acid phosphate (ACP), alkaline phosphate (ALP), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and catalase (CAT) in the hepatopancreas were presented in the starved-refed group at second week, and significantly higher than those in the control group (p < 0.05). Meanwhile, starvation significantly improved intestinal immune enzymes activities (p < 0.05). the lowest TG contents and the highest expression levels of lipolysis genes including hormone-sensitive lipase (HSL) and carnitine palmitoyl transferase 1 isoform A (CPT-1A) appeared in the hepatopancreas, muscle and intraperitoneal fat after starvation, indicating the mobilization of fat reserves in these tissues (p < 0.05). After refeeding, the recovery of TG content might be mediated by the upregulation of the expression levels of lipogenesis genes such as sterol regulatory element binding protein 1 (SREBP1) and fatty acid synthase (FAS). Understanding the duration of physiological and metabolic changes in O. macrolepis and their reversibility or irreversibility to supplementary feeding response could provide valuable reference for the adaptability of O. macrolepis in large-scale culturing, proliferation and release.

First Insights on the Administration of Insect Oil (Black Soldier Fly Larvae) in the Diet of Juvenile Onychostoma macrolepis.

The use of insect products in aquatic feed is the focus of the aquaculture industry. Black soldier fly larvae oil (BSFLO) has been examined as a potential lipid source for diets for some fish species, but its utilization on Onychostoma macrolepis has not been explored. The influences of substituting fish oil (FO) with BSFLO in the diet on growth, biological indicators, approximate composition, serum biochemistry, antioxidant capacity and expression of lipid metabolism genes in juvenile O. macrolepis were investigated in an eight-week feeding experiment. Four experimental diets were prepared by replacing 0 (control), 25% (BSFLO-25), 50% (BSFLO-50) and 100% (BSFLO-100) FO with BSFLO, and then randomly assigned to twelve aquariums with ten fish (1.75 ± 0.05 g) in each aquarium. The findings showed that the growth indicators, body composition and serum biochemistry in the BSFLO-25 and BSFLO-50 groups had no statistical differences from those of the control group. The activities of superoxide dismutase (SOD) (91.22-94.96 U/mgprot) and the contents of malondialdehyde (MDA) (1.12-1.16 nmol/mgprot) in the liver appeared to be significantly the highest and the lowest in the BSFLO-25, BSFLO-50 and BSFLO-100 groups (p < 0.05). The adipocyte size and intraperitoneal fat index value of fish fed on the BSFLO-100 diet were significantly decreased compared to the control group (p < 0.05). The expression levels of lipid catabolism genes pparα, (peroxisome proliferators-activated receptor alpha) and cpt1a (carnitine palmitoyltransferase 1 isoform a) in the BSFLO-100 group were significantly higher than those of the control group (p < 0.05). The above results indicated that it was feasible to replace 25-50% dietary FO with BSFLO in juvenile O. macrolepis. Dietary BSFLO supplementation could enhance the antioxidant capacity of the liver and suppress intraperitoneal fat accumulation in O. macrolepis. The use of other insect oils in the diets of this species will be evaluated in future research.

Trends and focuses of hantavirus researches: a global bibliometric analysis and visualization from 1980 to 2020.

BACKGROUND: There have been worldwide changes in the researches on hantaviruses in the past several decades. Nevertheless, there are few bibliometric analysis studies this field. We aim to evaluate and visualize the research focuses and trends of this field using a bibliometric analysis way to help understand the developmet and future hotspots of this field. MATERIAL AND METHODS: Publications related to hantavirus studies were culled from the Web of Science Core Collection to generate trend analysis. The articles and reviews were re-extracted and Countries, institutions, authors, references and keywords in this field were visually analyzed by using VOSviewer and CiteSpace. RESULTS: A total of 4408 studies were included and the number of publications regarding hantaviruses significantly increased yearly. Three thousand seven hundred sixteen research articles and reviews were retrieved to generate bibliometric analysis. These studies mainly come from 125 countries led by USA and China and 3312 institutions led by the University of Helsinki. Twelve thousand five hundred twenty nine authors were identified and Vaheri A were the most influential author. Journal of Virology was the journal with the most studies and citations. After analysis, Hemorrhagic fever with renal syndrome, Hantavirus cardiopulmonary syndrome, nephropathia epidemica and related genotypes, clinical symptoms and rodents were the most common keywords and developing areas. CONCLUSION: Research on hantavirus is flourishing. Cooperation among different countries and institutions in this field must be strengthened in the future. The ecology and clinical symptoms of new genotypes, the vaccine development and factors that affect host population distribution and density are current and developing areas of study.

Hantaviruses in rodents and humans, Xi'an, PR China.

Xi'an, the capital of Shaanxi province, located in north-west China, is one of the major endemic areas for haemorrhagic fever with renal syndrome (HFRS). In this study, the epidemiological data of HFRS in Xi'an from 1959 to 2010, especially in the past ten years (2001-2010), were surveyed. The features of hantavirus (HV) host carriers, the molecular characteristics of the HV S gene from hosts and patients, and the genome of the viral isolate were also investigated. Data showed that there might be a ten-year cycle of HFRS in Xi'an. Although the main population group infected over the past ten years was still the 16-59-year-old male farmers, the composition of the population and geographical distribution of HFRS cases have changed slowly, accompanied by the development of environmental and socio-economic situations. Apodemus agrarius remains the dominant host of HV. The HV strains from host rodents and patients in Xi'an belonged to the Hantaan virus (HTNV); no Seoul virus strains were found. Phylogenetic analysis of the small segments of strains taken from hosts and patients, and the whole genome of a viral isolate showed that the virus circulating in Xi'an had high similarity to Guizhou strains. The study also indicated that the vaccine candidate strain A16 isolated during the past century in Xi'an might be a recombinant strain of HTNV and the Amur virus, thus it may not be an optimal vaccine strain.