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Simple Summary: Schizothorax prenanti is a valuable cold-water fish that is commercially farmed in southwest China. Numerous aquaculture farmers have recently adopted high-density farming to achieve greater economic benefits, but this has rendered S. prenanti more susceptible to microbial pathogens and resulted in economic losses. Hence, the immune mechanisms of S. prenanti against pathogens should be investigated. Heat shock proteins (Hsps) comprise a family of molecular chaperones that are involved in immune pathways. Here, we identified and cloned the cDNA encoding SpHsp27 gene and detected its tissue distribution and using polyinosinic-polycytidylic acid [Poly (I:C)] as a viral analog to challenge the fish. We also explored the expression of SpHsp27, SpHsp60, SpHsp70, and SpHsp90 in four immune organs from fish that were injected with Poly (I:C). We found that Poly (I:C) induced SpHsp27 expression in all of these tissues, and significantly up-regulated most SpHsps genes compared with controls that were injected with phosphate-buffered saline. However, temporal expression and tissues were organ-specific. The present findings will help to further clarify the roles of Hsp genes in the mechanisms of antiviral immunity in fish. We identified and cloned cDNA encoding the heat shock protein (Hsp) 27 gene from Schizothorax prenanti (SpHsp27), and compared its expression with that of SpHsp60, SpHsp70, and SpHsp90 in the liver, head kidney, hindgut, and spleen of S. prenanti that were injected with polyinosinic-polycytidylic acid [Poly (I:C)]. The SpHsp27 partial cDNA (sequence length, 653 bp; estimated molecular mass, 5.31 kDa; theoretical isoelectric point, 5.09) contained an open reading frame of 636 bp and a gene encoding 211 amino acids. The SpHsp27 amino acid sequence shared 61.0–92.89% identity with Hsp27 sequences from other vertebrates and SpHsp27 was expressed in seven S. prenanti tissues. Poly (I:C) significantly upregulated most SpHsps genes in the tissues at 12 or 24 h (p < 0.05) compared with control fish that were injected with phosphate-buffered saline. However, the intensity of responses of the four SpHsps was organ-specifically increased. The expression of SpHsp27 was increased 163-fold in the head kidney and 26.6-fold SpHsp27 in the liver at 24 h after Poly (I:C) injection. In contrast, SpHsp60 was increased 0.97–1.46-fold in four tissues and SpHsp90 was increased 1.21- and 1.16-fold in the liver and spleen at 12 h after Poly (I:C) injection. Our findings indicated that Poly (I:C) induced SpHsp27, SpHsp60, SpHsp70, and SpHsp90 expression and these organ-specific SpHsps are potentially involved in S. prenanti antiviral immunity or mediate pathological process. [ABSTRACT FROM AUTHOR]

Simple Summary: The Taibai stream salamander (Batrachuperus taibaiensis) is a protected species endemic to the Zhouzhi Heihe River. Few traditional studies have been conducted on the distribution of B. taibaiensis, leading to irregular discoveries. Environmental DNA (eDNA) is an ideal species detection technique that can increase accuracy and decrease the cost of population surveys. Here, we have established an optimal method for obtaining the eDNA of B. taibaiensis from water samples, which provides a theoretical basis and reference for resource investigation and protection of B. taibaiensis. Moreover, this study highlights the detection of a rare species in a river for use in further research. The Taibai stream salamander (Batrachuperus taibaiensis) is a recently described species of the genus Batrachuperus that occurs in the Zhouzhi Heihe River and is endangered in its native range. Here, we have established a method for water environmental DNA (eDNA) analysis of Batrachuperus using a series of optimizations. We have designed a specific set of primers for the genus Batrachuperus to amplify a 160 bp fragment of Cytb. The sequences were obtained from nested PCR on eDNA extracted from water samples, after which DNA barcoding was performed according to sequence analysis to determine the presence of the target species in the water. The method was validated using water from the Zhouzhi Heihe River with known B. taibaiensis populations and found that B. taibaiensis eDNA can move at least 150 m downstream from its point of origin. This study is the first to establish an optimal method for obtaining the eDNA of Batrachuperus from water samples, which provides a theoretical basis for resource investigation and the protection of B. taibaiensis in future research. It is also an example of the eDNA extraction of other species that live in similar waters and are less genetically diverse between species. [ABSTRACT FROM AUTHOR]