摘要
副溶血弧菌(Vibrio parahaemolyticus)是常见的食源性致病菌和海水养殖动物致病菌,目前已知的毒力基因有tlh、tdh、trh、T3SS、pirA、pirB、toxR/S、orf8等。盐度是影响细菌基因表达的关键生态因子之一,为进一步探求副溶血弧菌的致病机理,对2株分别分离自海水和淡水养殖发病凡纳滨对虾(Litopenaeus vannamei)中的副溶血弧菌在不同盐度下的生长速率、致病性进行检测,并用q-PCR方法对菌株毒力基因携带和表达情况进行定量研究。实验结果表明:海水菌株383生长速率快于淡水菌株V9,但菌株383在生长稳定期的细菌浓度明显低于菌株V9;菌株383对凡纳滨对虾的致病性明显高于菌株V9,前者的48 h半致死浓度(LD50)低于后者2个数量级;2株副溶血弧菌皆携带毒力基因tlh、T3SS1和pirA/B,但未检测到tdh、trh、T3SS2、toxR/S和orf8。部分毒力基因表达量检测结果显示,菌株383和菌株V9均为vcrD1表达量最高,其次是pirA,vopD1表达量最低;4个毒力基因不仅在2菌株间的表达量差别较大,而且盐度对同一菌株不同毒力基因表达的影响也是不同的。2株副溶血弧菌的毒力与pirA和vcrD1的表达量呈正相关性。研究结果为探究环境因素与副溶血弧菌致病力的关系提供了科学依据,同时也提示,淡水养殖凡纳滨对虾要防范副溶血弧菌输入的风险。
Vibrio parahaemolyticusis is a foodborne and marine aquaculture pathogen, and the known virulence genes in V. parahaemolyticus include tlh, tdh, trh,T3 SS,pirA, pirB, toxR/S and orf8. Salinity is one of the key ecological factors affecting bacterial gene expression. The growth rate, pathogenicity,and the expression of virulence genes on two strains of V. parahaemolyticus(strain 383 from seawater aquaculture and strain V9 from freshwater aquaculture) under different salinities were compared. The results showed that the growth rate of strain 383 was faster than that of strain 383, but the bacterial concentration of strain 383 was lower than that of strain V9 in the stable growth period. The pathogenicity of strain 383 to Litopenaeus vannamei was significantly higher than that of strain V9, and the 48-h half lethal concentration(LD50) of strain 383 was significantly lower than that of strain V9. Both strains carried the virulence genes of TLH, T3 SS1 and pirA/B, but tdh, trh, T3 SS2, toxR/S and orf8 were not detected. The RT-PCR results showed that both strain 383 and strain V9 had the highest expressions of vcrD1, followed by pirA and the expression of vopD1 was the lowest.The expression of four virulence genes were different between two strains, and the effects of salinity on the expression of different virulence genes in the same strain were different.The virulence of two V. parahaemolyticus strains was positively correlated with the expression of pirA and vcrD1. The results provide a scientific basis for exploring the relationship between environmental factors and virulence of V. parahaemolyticus.It is suggested that the risk of importation of V. parahaemolyticus in Litopenaeus vannamei cultured in freshwater should be prevented.
作者
黄倞
王元
马清扬
英娜
赵姝
吴越
房文红
HUANG Liang;WANG Yuan;MA Qing-yang;YING Na;ZHAO Shu;WU Yue;FANG Wen-hong(Key Laboratory of East China Sea Fisheries Resources Exploitation and Utilization,Ministry of Agriculture,East China Sea Fisheries Rsearch Institute,Chinese Academy of Fishery Sciences,Shanghai 200090,China;College of Fisheries and Life Science,Shanghai Ocean University,Shanghai 201306,China)
出处
《海洋渔业》
CSCD
北大核心
2019年第6期704-711,共8页
Marine Fisheries
基金
中国水产科学研究院基本科研业务费(2017HY-ZD1006)
上海市科委科研计划项目(17391902400)
关键词
副溶血弧菌
致病性
盐度
毒力因子
基因表达
Vibrio parahaemolyticus
pathogenicity
salinity
virulence factors
gene expression
