A metagenomic insight into the Yangtze finless porpoise virome.

The Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) inhabiting the Yantze River, China is critically endangered because of the influences of infectious disease, human activity, and water contamination. Viral diseases are one of the crucial factors that threatening the health of Yangtze finless porpoise. However, there are few studies which elaborate the viral diversity of Yangtze finless. Therefore, this study was performed to investigate the viral diversity of Yangtze finless by metagenomics. Results indicated that a total of 12,686,252 high-quality valid sequences were acquired and 2,172 virus reads were recognized. Additionally, we also obtained a total of 10,600 contigs. Phages was the most abundant virus in the samples and the ratio of DNA and RNA viruses were 69.75 and 30.25%, respectively. Arenaviridae, Ackermannviridae and Siphoviridae were the three most predominant families in all the samples. Moreover, the majority of viral genus were Mammarenavirus, Limestonevirus and Lambdavirus. The results of gene prediction indicated that these viruses play vital roles in biological process, cellular component, molecular function, and disease. To the best of our knowledge, this is the first report on the viral diversity of Yangtze finless porpoise, which filled the gaps in its viral information. Meanwhile, this study can also provide a theoretical basis for the establishment of the prevention and protection system for virus disease of Yangtze finless porpoise.

Characterization and phylogenetic analysis of the complete mitochondrial genome of sun loach (Yasuhikotakia eos).

The complete mitochondrial genome of the sun loach (Yasuhikotakia eos) was determined based on Illumina data in this study. The result showed that the closed double-stranded circular mitogenome was 16,738 bp in total length (GenBank accession number: MT800510) with 58.41% AT. The mitochondrial DNA consisted of 13 protein-coding genes (PGCs), 22 transfer RNA (tRNA) genes, 2 ribosomal (rRNA) genes, and 1 non-coding control region. Phylogenetic analysis suggested that Y. eos was most closely related to its congener Y. modesta. This work provides molecular information for further research on species identification and evolutionary relationships.

Comparative analysis of microbial community structure between healthy and Aeromonas veronii-infected Yangtze finless porpoise.

BACKGROUND: The gut microbiota is a complex ecosystem, which is essential for the metabolism, health and immunity of host. Many diseases have been shown to be closely related to the alteration of intestinal flora. Aeromonas veronii as a conditioned pathogen can cause disease in Yangtze finless porpoise through intestinal infections. However, it is not clear whether the disease caused by Aeromonas veronii is related to changes of intestinal flora. In the current study, the diversity and composition of gut microbiota in the healthy and Aeromonas veronii-infected Yangtze finless porpoise were evaluated by high-throughput sequencing to further investigate the potential association between intestinal flora alteration and pathogen invasion. RESULTS: A total of 127,3276 high-quality sequences were achieved and 2465 operational taxonomic units (OTUs) were in common among all samples. The results of alpha diversity showed that there was no obvious difference in richness and diversity between healthy and Aeromonas veronii-infected Yangtze finless porpoise. Firmicutes, Bacteroidetes and Proteobacteria were the most dominant phyla in all samples. In addition, the healthy Yangtze finless porpoise exhibited higher abundance of Firmicutes and Fusobacteria than Aeromonas veronii-infected Yangtze finless porpoise, while, the level of Proteobacteria was decreased. At the genus level, Paeniclostridium and Paraclostridium were the predominant bacteria genera in the CK (healthy Yangtze finless porpoise) group. In the DIS (Aeromonas veronii-infected Yangtze finless porpoise) group, Lactobacillus and unidentified_Enterobacteriaceae were the dominant bacteria genera and the proportion of Paeniclostridium, Paraclostridium, Terrisporobacter, Cetobacterium, Candidatus Arthromitus, Terrabacter and Dechloromonas were reduced. CONCLUSIONS: In conclusion, our results showed that Aeromonas veronii infection can alter the gut microbiota of the Yangtze finless porpoise by affecting the number of harmful bacteria and beneficial bacteria.

One new species of the subgenus Hexatoma (Eriocera) Macquart (Diptera, Limoniidae) from China with a key to Chinese species.

One new species of the subgenus Eriocera Macquart, 1838, Hexatoma (Eriocera) cleopatroides Men, sp. n. (Southern China: Anhui) is described and illustrated. A key to all of 78 known species from China in the subgenus is provided, which was solely based on literatures. The new species is similar to Hexatoma (Eriocera) cleopatra Alexander, 1933, but distinguishes from the latter by the prescutum entirely black with two ill-defined gray stripes, by the legs with fore and middle femora brown in basal half, black in apical half, with hind femora brown in basal one-fourth, and by the wings with cells c and sc more yellowish brown than the ground color.

Effects of fish community on occurrences of Yangtze finless porpoise in confluence of the Yangtze and Wanhe Rivers.

The Yangtze finless porpoise is a subspecies of narrow-ridged finless porpoise endemic to the middle and lower reaches of the Yangtze River and the adjoining Poyang and Dongting Lakes. With the depletion of fish stocks in the Yangtze River in recent decades, food availability has become the most important factor affecting the survival of this subspecies. Despite this, the relationships between fish community and occurrences of porpoise are far from being fully understood. Therefore, during September 2013 to August 2014, the occurrences of porpoise were investigated in confluence of the Yangtze and Wanhe Rivers; fish community was also surveyed synchronously in confluence and two adjacent transects. The results showed that (1) the confluence had maximum fish species richness, and the main dominant species was upper fish, while the other two transects were mainly dominated by demersal fish. ANOVA analyses showed that individual number and yield of upper fish which can be eaten by porpoise (upper edible fish) in the confluence were significantly higher than other two transects. (2) Average group size of the porpoise was 3.7 ± 1.8 individuals. The occurrences of porpoise in different seasons had great differences, and the porpoise was more likely to be detected in autumn and winter. (3) Fish community had significant effects on occurrences of porpoise, and the main influencing factors were fish species richness, individual number, and yield of edible fish, especially the upper edible fish. The results of this study will have important implications for the conservation of porpoise.