凡纳滨对虾优势腐败菌鉴定及其群体感应现象

Identification and quorum sensing of dominant spoilage bacteria from Litopenaeus vannamei

摘要:

为了鉴定凡纳滨对虾的优势腐败菌并研究其是否存在以N?酰基高丝氨酸内酯类化合物(AHLs)介导的群体感应系统, 采用16S rRNA序列鉴定凡纳滨对虾的优势腐败菌, 并采用紫色杆菌CV026对优势腐败菌的AHLs活性进行检测。结果发现凡纳滨对虾优势腐败菌菌株1 (Aci-1)和菌株2 (Aci-2)均为不动杆菌属, 均存在以AHLs为信号分子的群体感应系统。添加外源信号分子AHLs能促进Aci?1菌株生物膜的形成, 且呈浓度依赖性。在一定的贮藏范围内, 凡纳滨对虾腐败菌信号分子AHLs浓度与细菌总数、挥发性盐基氮含量存在正相关性, 其相关系数r分别为0.846 6和0.986 7, 分别在P<0.05与P<0.01水平上显著。结论是凡纳滨对虾优势腐败菌不动杆菌菌株存在以AHLs介导的群体感应系统, 且与凡纳滨对虾的腐败密切相关。

Abstract:

This study was to investigate the dominant spoilage bacteria (DSB) of shrimp and detect the quorum sensing mediated by N?acyl?homoserine lactones (AHLs). The strains of DSB were identified by 16S rRNA gene sequence. AHLs of DSB were detected with strain Chromobacterium violaceum CV026. The results indicated that two strains Aci-1 and Aci-2 belong to Acinetobacter spp.. Both bacterial strains can secret AHLs, and the biofilm formation of Aci-1 were significantly affected by exogenous AHLs. There is a positive relationship between the AHLs activity of DSB and the total plate count and TVB-N content of shrimp, and the correlation coefficient is 0.846 6 (P<0.05) and 0.986 7 (P<0.01), respectively. The DSB of shrimp have the quorum sensing system mediated by AHLs, which plays an important role in the spoilage of shrimp.