High-throughput metabolomics method based on liquid chromatography-mass spectrometry: Insights into the underlying mechanisms of salinity-alkalinity exposure-induced metabolites changes in Barbus capito.

It is critical to investigate the adaptive development and the physiological mechanism of fish in external stimulation. In this study, the response of Barbus capito to salinity-alkalinity exposure was explored by high-throughput nontargeted and liquid chromatography-mass spectrometry-based metabolomics to investigate metabolic biomarker and pathway changes. Meanwhile, the biochemical indexes of Barbus capito were measured to discover the chronic impairment response to salinity-alkalinity exposures. A total of 29 tissue metabolites were determined to deciphering the endogenous metabolic changes of fishes during the different concentration salinity-alkalinity exposures environment, which were mainly involved in the key metabolism including the phenylalanine, tyrosine, and tryptophan biosynthesis, arachidonic acid metabolism, pyruvate metabolism, citrate cycle, and glycerophospholipid metabolism. Finally, we found the amino acid metabolism as key target was associated with the endogenous metabolites and metabolic pathways of Barbus capito to salinity-alkalinity exposures. In conclusion, metabolomics is a potentially powerful tool to reveal the mechanism information of fish in various exposure environments.

Mitochondrial DNA sequence of Culter compressocorpus.

In this study, the complete mitochondrial genome of Culter compressocorpus was detected and annotated. The circular mtDNA molecule was 16,623 bp in length which contains 22 transfer RNA genes, 13 protein-coding genes, 2 ribosomal RNA genes, and the non-coding control region (D-loop). Its total protein-coding genes content is 68.67% in whole mitochondrial genome. The mitochondrial genome can contribute to the studies on geographical distribution and genetic diversity of C. compressocorpus resources, as well as molecular phylogeny and species identification in Cyprinidae.

Mitochondrial DNA sequence of Pseudorasbora parva (Cyprinidae: Gobioninae).

In this study, the complete mitochondrial genome of Pseudorasbora parva (Cyprinidae: Gobioninae) was determined. The circular mtDNA molecule was 16,601 bp in length which contains 22 transfer RNA genes, 13 protein-coding genes, 2 ribosomal RNA genes and non-coding control region (D-loop). The critical central conserved sequences were also detected. Its total A + T content is 55.97%. The mitochondrial genome can contribute to the studies on geographical distribution and genetic diversity of P. parva resources, as well as molecular phylogeny and species identification in Cyprinidae.

[Evaluation of ivermectin's reproductive toxicity to male Carassius auratus].

As a new type of antiparasitic drugs, ivermectin (IVM) has been widely applied in agriculture, stock raising and aquaculture in China because of its broad spectrum and high efficiency. In order to evaluate the IVM' s reproductive toxicity to male Crucian carp (Carassius auratus), IVM was orally given to the experimental fish with different dosages and the gonadosomatic index (GSI), sexual hormone contents (including testosterone and estradiol) in serum and testis, γ-aminobutyric acid content in serum and brain tissues, ultra-structure of spermatozoa and gonadal tissue in fish were determined in this study. The experimental fish were classified into A, B, C and D groups corresponding to the different dosages of IVM (0, 0.3, 0.9 and 1.5 mg . kg-1, respectively once a day for 3 days continuously). Several indices in fish were detected after 8 days self-purification. The results indicated that GSI gradually decreased with the increase of drug dosage, and GSI in groups C and D was significantly lower than that in group A. The contents of testosterone, estradiol and y-aminobutyric acid exhibited a trend of first increasing and then decreasing and reached the peak at group B. Sperm longevity gradually decreased and the motion time also decreased in II, III and IV level sperms with the increasing dosage of IVM, which appeared to be especially obvious in group C and D. No obvious differences were found in the ultra-structure of spermatozoa and gonadal tissues. In conclusion, this study suggested that IVM had no obvious reproductive toxicity to male Crucian carp at the normal therapeutic dosage but could cause serious potential reproductive toxicity to fish at a high concentration.

The Complete mitochondrial genome of Spinibarbus denticulatus (Oshima).

Spinibarbus denticulatus (Oshima) is a rare and commercial fish. The complete mitochondrial genome sequence of S. denticulatus will help us to study the genetic of conversation, such as the genetic diversity and genetic structure, and provides the basis for the study in evolution. In this paper, the complete mitochondrial genome of S. denticulatus was determined to be 16,549 bp in length by Sanger sequencing technology. Thirteen protein-coding genes, 22 tRNA genes and 2 ribosomal genes were characterized. We also analyzed the structure of control region, 6 CSBs (CSB-1, CSB-2, CSB-3, CSB-D, CSB-E and CSB-F) and 1 TAS were identified, the control region also included an AT unit tandem repeat with 17 repeat times.

Mitochondrial DNA sequence of Mongolian redfin (Chanodichthys mongolicus).

Monglian redfin is a kind of freshwater aquaculture species which has an important economic value in China. In this study, we report the complete sequence of mitochondrial genome of Monglian redfin. The complete mitochondrial genome sequence is determined to be 16,621 base pairs (bp) in length and contain 13 protein-coding gene (PCGs), 22 transfer RNA genes, large (rrnL) and small (rrnS) ribosomal RNA, and the non-coding control region. Its total A+T content is 55.98%. We also analyzed the structure of control region, six conserved sequence blocks (CSBs) (CSB-1, CSB-2, CSB-3, CSB-D, CSB-E and CSB-F) and one potential termination-associated sequence were detected and the control region also included a 2-bp tandem repeat with eight repeat times.