大菱鲆荧光假单胞菌的群体感应现象及不同碳源培养下的腐败特性研究

本文以大菱鲆分离的荧光假单胞菌作为研究对象,紫色杆菌CVO26平行划线法检测信号分子。不同碳源(葡萄糖、蔗糖、果糖、木糖、乳糖、麦芽糖)的AB培养基培养并检测其生物被膜、嗜铁素和胞外蛋白酶的产生量,同时添加外源的信号分子标准品,研究AHLs与腐败因子之间的相关性。研究表明:大菱鲆分离的荧光假单胞菌能够发生群体感应现象,经不同碳源培养,其腐败因子产生情况有明显差异,碳源的添加对生物被膜的产生有促进作用,对胞外蛋白酶的产生没有显著影响;以葡萄糖、麦芽糖为碳源,生物被膜的产生量较高;以蔗糖和乳糖为碳源,嗜铁素的产量较高。添加外源信号分子标准品,生物被膜、嗜铁素和胞外蛋白酶的产生量有显著提高。因此,生物被膜、嗜铁素和胞外蛋白酶的产生与AHLs有关,群体感应现象可调控腐败特性的表达,并在水产品腐败过程中发挥作用。

Quorum-sensing Phenomenon in Pseudomonas fluorescens Isolated from Turbot and Spoilage Characteristics Using Different Carbon Sources

Pseudomonas fluorescens isolated from turbot was used as a test strain. Quorum-sensing signal molecules were detected by a parallel streak method using Chromobacterium violaceum CVO26 strain. The bacteria were cultured in AB medium supplemented with different carbon sources (glucose, sucrose, fructose, xylose, lactose, or maltose), and biofilm formation, and siderophore and extracellular protease production was measured. Simultaneously, N-acylhomoserine lactones (AHLs), a class of external quorum-sensing compound, were added to the culture in order to determine the relationship between AHLs and spoilage factors. Quorum-sensing phenomenon was observed in the tested strain culture, and the production of spoilage factors significantly differed between different carbon sources used. The addition of carbon sources promoted biofilm formation, but it had no significant influence on the production of extracellular protease. The biofilm formation was relatively high when glucose and maltose were used as the carbon source, and a relatively high rate of siderophore production was observed when sucrose and lactose were used. The biofilm formation and siderophore and extracellular protease production were significantly enhanced when the external quorum-sensing signal molecules were added. Therefore, the biofilm formation and siderophore and extracellular protease production are related to AHLs, and quorum-sensing phenomenon might control the effects of spoilage factors, and play a role in the spoilage of aquatic products.