Fisheries College, Jimei University, Xiamen, 361021, China.
Engineering Research Center of the Modern Industry Technology for Eel. Ministry of Education of PRC, Xiamen, 361021, China.
Mar Biotechnol (NY). 2024 Apr;26(2):306-323. doi: 10.1007/s10126-024-10298-9. Epub 2024 Feb 17.
Vibrio harveyi, a recently discovered pathogenic bacterium isolated from American eels (Anguilla rostrata), poses uncertainties regarding its pathogenesis in American eel and the molecular mechanisms underlying host defense against V. harveyi infection. This study aimed to determine the LD of V. harveyi in American eel and assess the bacterial load in the liver, spleen, and kidney post-infection with the LD50 dose. The results showed that the LD of V. harveyi via intraperitoneal injection in American eels over a 14d period was determined to be 1.24 × 10 cfu/g body weight (6.2 × 10 cfu/fish). The peak bacterial load occurred at 36 h post-infection (hpi) in all three organs examined. Histopathology analysis revealed hepatic vein congestion and thrombi, tubular vacuolar degeneration, and splenic bleeding. Moreover, quantitative reverse transcription polymerase chain reaction (qRT-PCR) results indicated significant up or downregulation of 18 host immune- or anti-infection-related genes post 12 to 60 hpi following the infection. Additionally, RNA sequencing (RNA-seq) unveiled 7 hub differentially expressed genes (DEGs) and 11 encoded proteins play crucial roles in the anti-V. harveyi response in American eels. This study firstly represents the comprehensive report on the pathogenicity of V. harveyi to American eels and RNA-seq of host's response to V. harveyi infection. These findings provide valuable insights into V. harveyi pathogenesis and the strategies employed by the host's immune system at the transcriptomic level to combat V. harveyi infection.
哈维弧菌是一种最近从美洲鳗（Anguilla rostrata）中分离出来的致病性细菌，其在美洲鳗中的发病机制以及宿主抵抗哈维弧菌感染的分子机制尚不确定。本研究旨在确定哈维弧菌在美洲鳗中的半数致死剂量（LD），并评估感染 LD50 剂量后肝脏、脾脏和肾脏中的细菌载量。结果表明，美洲鳗腹腔注射哈维弧菌 14 天的 LD 为 1.24×10 cfu/g 体重（6.2×10 cfu/鱼）。在所有三个检查的器官中，细菌载量在感染后 36 小时达到峰值。组织病理学分析显示肝静脉充血和血栓形成、肾小管空泡变性和脾脏出血。此外，定量逆转录聚合酶链反应（qRT-PCR）结果表明，感染后 12 至 60 小时，18 个宿主免疫或抗感染相关基因的表达显著上调或下调。此外，RNA 测序（RNA-seq）揭示了 7 个差异表达基因（DEG）和 11 个编码蛋白在美洲鳗抗哈维弧菌反应中发挥重要作用。本研究首次全面报道了哈维弧菌对美洲鳗的致病性和宿主对哈维弧菌感染的 RNA-seq 反应。这些发现为哈维弧菌发病机制以及宿主免疫系统在转录组水平上抵抗哈维弧菌感染的策略提供了有价值的见解。
