碳源及温度对食源假单胞菌群体感应信号分子产生的影响

许多革兰氏阴性菌通过产生N-酰基-高丝氨酸内酯（AHLs）类信号分子来调控某些性状的表达，即群体感应（quorum sensing）。假单胞菌是一种导致食品腐败的重要腐败细菌，也产生AHLs。本文研究了不同温度及碳源对食源假单胞菌AHLs产生的影响。结果表明，该假单胞菌在25℃条件下，产生两种AHL信号分子，而在4℃条件下，所产生的短链AHL分子消失，主要产生长链AHL分子。而且在不同碳源（葡萄糖，果糖，木糖，麦芽糖等）的培养基中生长，所产生的AHLs分子种类也不同。同时发现当pH>7.5时，AHLs的稳定性下降。由此得出，在不同的环境条件(碳源及温度)下假单胞菌所产生的AHLs种类不同。为进一步研究群体感应现象在食品腐败中的作用以及开发基于干扰腐败菌群体感应的新型食品防腐技术提供研究基础。

Effect of Temperature and Carbon Source on the N-acyl-homoserine lactones Production by Food-derived Pseudomonas

The many Gram-negative bacteria regulated the expression of some traits by producing the small molecules N-acyl-homoserine lactones (AHLs), i.e., quorum sensing. Pseudomonas ,an important bacteria that caused spoilage of food produced AHLs. In this study, we tested the influence of carbon source, temperature on the AHLs profile produced by food-derived Pseudomonas. The results showed that the strains produced two types of AHLs at 25℃. However, the long chain AHLs were produced mainly, and the short chain AHLs disappeared when the strains were grown at 4℃. The strains produced the different types of AHLs when grown in the different carbon source(glucose, fructose, xylose, maltose). Also the AHLs signal molecules became unstable with increasing pH(>7.5). Overall, our research demonstrates the effect of environmental parameters (temperature and carbon source) on AHL profile production by food-derived Pseudomonas. This study lays the foundation for further investigation to elucidate the relationship between quorum sensing and food spoilage, and for the development of new food preservative by blocking the quorum sensing of food spoilage bacteria.