Abstract Background With the intensification of global warming, rainbow trout ( Oncorhynchus mykiss ) suffer from varying degrees of thermal stimulation, leads to mass mortality, which severely restrict the development of aquaculture. Understanding the molecular regulatory mechanisms of rainbow trout under heat stress is useful to develop approaches to relieve symptoms. Results Changes in nonspecific immune parameters revealed that a strong stress response was caused in rainbow trout at 24 °C, so we performed multiple transcriptomic analyses of rainbow trout liver under heat stress (HS, 24 °C) and control conditions (CG, 18 °C). A total of 324 DEcircRNAs, 105 DEmiRNAs, and 1885 DEmRNAs were identified. A ceRNA regulatory network was constructed and a total of 301 circRNA-miRNA and 51 miRNA-mRNA negative correlation pairs were screened, and three regulatory correlation pairs were predicted: novel_circ_003889 - novel-m0674-3p - hsp90ab1 , novel_circ_002325 - miR-18-y - HSPA13 and novel_circ_002446 - novel-m0556-3p - hsp70 . Some target genes involved in metabolic processes, biological regulation or response to stimulus were highly induced at high temperatures. Several important pathways involved in heat stress were characterized, such as protein processing in the ER, the estrogen signaling pathway, and the HIF-1 signaling pathway. Conclusions These results extend our understanding of the molecular mechanisms of the heat stress response and provide novel insight for the development of strategies that relieve heat stress.
Abstract Background Specific pathogen-free ducks are a valuable laboratory resource for waterfowl disease research and poultry vaccine development. High throughput sequencing allows the systematic identification of structural variants in genomes. Copy number variation (CNV) can explain the variation of important duck genetic traits. Herein, the genome-wide CNVs of the three experimental duck species in China (Jinding ducks (JD), Shaoxing ducks (SX), and Fujian Shanma ducks (SM)) were characterized using resequencing to determine their genetic characteristics and selection signatures. Results We obtained 4,810 CNV regions (CNVRs) by merging 73,012 CNVs, covering 4.2% of the duck genome. Functional analysis revealed that the shared CNVR-harbored genes were significantly enriched for 31 gene ontology terms and 16 Kyoto Encyclopedia of Genes and Genomes pathways (e.g., olfactory transduction and immune system). Based on the genome-wide fixation index for each CNVR, growth ( SPAG17 and PTH1R ), disease resistance ( CATHL3 and DMBT1 ), and thermoregulation ( TRPC4 and SLIT3 ) candidate genes were identified in strongly selected signatures specific to JD, SM, and SX, respectively. Conclusions In conclusion, we investigated the genome-wide distribution of experimental duck CNVs, providing a reference to establish the genetic basis of different phenotypic traits, thus contributing to the management of experimental animal genetic resources.
The sequence polymorphisms of mtDNA D-loop hypervariable region(mtDNA D-loop HVI) were studied in six populations of Triplophysa. The results showed that 149 polymorphic sites were detected in a total length of 570 bp nucleotide sequence, thus defining 39 haplotypes. Among the six populations, the haplotype diversity(Hd)from high to low was T. stenura(0.899)>T. orientalis>T. siluroides>T. dalaica/T. pappenheimi >T. xiangxiensis(0.286), the order of nucleotide diversity(Pi) was T. siluroides(0.042 59)>T. pappenheimi>T. stenura>T. orientalis>T. dalaica>T. xiangxiensis(0.000 5). The genetic distance between the T. stenura and the T. xiangxiensisa is the largest(0.186), and the genetic distance between Triplophysa dalaica and Triplophysa orientalis is the lowest(0.027). The genetic differentiation between T. stenura and T. dalaica was the largest(0.989), and the genetic differentiation between T. siluroides and T. orientalis was the lowest(0.222). Among them, there was only one shared haplotype(Hap29) which was shared by T. dalaica and T. siluroides. The rest were characteristic haplotypes. The phylogenetic tree showed that the six Triplophysa populations were clustered into three groups. Among them, T.stenura was clustered only a group, and Triplophysa xiangxiensis and T. poppenheimi were clustered a group, and T.orientalis, T. dalaica and T. siluroides were clustered together. The results of network and phylogenetic tree were basically consistent. In terms of overall haplotype richness and nucleotide diversity, there was a high genetic diversity of T. stenura and low of T. xiangxiensisa. In terms of the phylogenetic relationship, the degree of difference among groups supports their taxonomic status, T. siluroides, T. orientalis and T. dalaica were relatively closer, different clusterings suggested that the Triplophysa may have experienced at least three domestication events. The results provided a genetic basis for the evaluation of biodiversity conservation of Triplophysa.
Heat stress leads to altered expression of associated heat shock proteins (HSPs), which are critical molecular chaperones related to cellular function in living organisms. Selenium nanoparticles (SeNPs), a nanocomposite form of Se, have a protective effect against heat stress-induced cellular damage. In this study, primary rainbow trout hepatocytes were isolated to identify the protective function of SeNPs in rainbow trout hepatocytes. Experiments were divided into five groups and SeNPs were added at concentrations of 0, 2.0, 3.0, 5.0 and 8.0 μg/mL and incubated at 18 ℃ for 4, 8, 12, 24 and 48 h respectively. Hepatocyte viability, GSH-Px and SOD activity were enhanced and MDA content was reduced following the addition of SeNPs. Expression of GSH-P1 and genes related to HSPs (including HSP70a, HSP60, HSP90β, HSP10 and HSP47) were significantly increased and the optimal concentration of SeNPs for adding to hepatocytes was identified as 5.0 µg/mL. Adding 5.0 µg/mL SeNPs following heat stress (24 ℃) increased hepatocyte viability, GSH-Px and SOD activity, while MDA levels first decreased and then increased. Expression of GSH-P1 and genes related to HSPs (including HSP70a, HSP60, HSP90β, HSP10 and HSP47) were significantly higher than controls. In summary, SeNPs and slight heat stress synergistically enhanced the expression of GSH-P1 and HSPs and protected hepatocytes from heat stress damage, suggesting that SeNPs is a potential hepatocyte protective therapeutic agent.
Evidence from previous reports indicates that pig domestication in East Asia mainly occurred in the Mekong region and the middle and downstream regions of the Yangtze River. Further research identified two new origin centers for domestic pigs in the Tibetan Plateau and the islands of Southeast Asia. However, due to the small sample size of Tibetan pigs, details of the origin and spread of Tibetan pigs has not yet been established.
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