Zhong Yunqi, He Zihao, Long Xinxin, Hou Danqing, Hu Xianye, Sun Chengbo
College of Fisheries, Guangdong Ocean University, Zhanjiang, China.
Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, China.
J Fish Dis. 2023 Nov;46(11):1207-1224. doi: 10.1111/jfd.13840. Epub 2023 Aug 17.
In recent years, due to the destruction of the culture environment and serious ecological pressure, especially in the process of culture, residual bait, faeces and fishery drug abuse will lead to the accumulation of harmful metabolites such as ammonia nitrogen and nitrite, and biological denitrification is the most economical and effective method to remove the single. Therefore, in this study, a nitrite removal strain XA19 was isolated and screened from a shrimp biofloc culture pond. This strain was identified as a clade of Vibrio proteolyticus because the homology between XA19 and V. proteolyticus WDVP was as high as 99.86% by using 16S rDNA gene sequence analysis and NCBI database comparison. Scanning electron microscopy images showed that V. proteolyticus is short-rod-shaped with a curved body and no budding spores, pods and flagella. Antimicrobial susceptibility test proved that V. proteolyticus was resistant to ampicillin, oxacillin, penicillin, vancomycin and clindamycin. In the median lethal concentration 50 (LC ) test, at 7-day post-infection (dpi), LC of V. proteolyticus for Fenneropenaeus merguiensis was 1.69 × 10 CFU/mL. Transcriptome sequencing analysis was carried out on hepatopancreas of F. merguiensis at 24 and 48 hpi. A total of 176 differentially expressed genes (DEGs) were screened at 24 hpi, including 104 up-regulated DEGs and 72 down-regulated DEGs, and a total of 52 DEGs were screened at 48 hpi, including 32 up-regulated DEGs and 20 down-regulated DEGs. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs, many immune-related signalling pathways were significantly enriched, including Hippo signalling pathway, phagosome, Toll and Imd signalling pathways and Wnt signalling pathway. In addition, some pathways related to Warburg effect were also enriched, including Glycolysis/Gluconeogenesis, Biosynthesis of amino acids, amino sugar and nucleotide sugar metabolism and so on. In this study, the toxicity and drug sensitivity of V. proteolyticus were systematically studied, and the immune response of hepatopancreas of F. merguiensis to V. proteolyticus infection was preliminarily revealed from the molecular level. The results may provide a reference for the prevention and control of V. proteolyticus.
近年来，由于养殖环境遭到破坏以及面临严重的生态压力，尤其是在养殖过程中，残饵、粪便以及渔业药物滥用会导致氨氮和亚硝酸盐等有害代谢产物积累，而生物脱氮是去除单一有害物质最经济有效的方法。因此，在本研究中，从对虾生物絮团养殖池塘中分离筛选出一株亚硝酸盐去除菌株XA19。通过16S rDNA基因序列分析并与NCBI数据库比对，该菌株被鉴定为溶蛋白弧菌属的一个分支，因为XA19与溶蛋白弧菌WDVP的同源性高达99.86%。扫描电子显微镜图像显示，溶蛋白弧菌呈短杆状，菌体弯曲，无芽孢、荚膜和鞭毛。药敏试验证明，溶蛋白弧菌对氨苄西林、苯唑西林、青霉素、万古霉素和克林霉素耐药。在半数致死浓度50（LC₅₀）试验中，感染后7天（dpi），溶蛋白弧菌对墨吉对虾的LC₅₀为1.69×10⁹ CFU/mL。对墨吉对虾在感染后24小时和48小时的肝胰腺进行转录组测序分析。在感染后24小时共筛选出176个差异表达基因（DEGs），其中上调的DEGs有104个，下调的DEGs有72个；在感染后48小时共筛选出52个DEGs，其中上调的DEGs有32个，下调的DEGs有20个。在对DEGs进行京都基因与基因组百科全书（KEGG）通路富集分析时，许多免疫相关信号通路显著富集，包括Hippo信号通路、吞噬体、Toll和Imd信号通路以及Wnt信号通路。此外，一些与瓦伯格效应相关的通路也被富集，包括糖酵解/糖异生、氨基酸生物合成、氨基糖和核苷酸糖代谢等。本研究系统地研究了溶蛋白弧菌的毒性和药敏性，并从分子水平初步揭示了墨吉对虾肝胰腺对溶蛋白弧菌感染的免疫反应。研究结果可为溶蛋白弧菌的防控提供参考。
