中文摘要：

【目的】探讨禽致病性大肠杆菌（Avian Pathogenic Escherichia coli,APEC）在不同生长时期和不同培养条件下,信号分子AI-2（Autoinducer-2,AI-2）的合成与luxS和pfs的转录水平之间的关系。【方法】利用哈维弧菌BB170（vibrio harveyi BB170）检测不同生长时期和不同培养条件下APEC的AI-2活性。同时利用Real-time PCR检测APEC不同生长时期和不同培养条件下luxS和pfs的转录水平。【结果】APEC在不同生长时期的AI-2活性与luxS的转录水平保持一致。培养基中加入葡萄糖,麦芽糖和NaCl后,AI-2活性和luxS转录水平都上调,加入蔗糖后则都下调,两者保持一致性。AI-2活性与pfs的转录水平则并不一致。【结论】APEC的AI-2产生水平与luxS的转录水平有高度的相关性,而与pfs的转录水平没有显著相关性;葡萄糖、麦芽糖和NaCl,促进AI-2的合成。

英文摘要：

【Objective】 In this study,the relationship between the transcription level of luxS and pfs and AI-2 production in different growth phases and culture conditions were analyzed.【Method】 AI-2 activity in different growth phases and culture conditions was measured using the V.harveyi bioluminescence assay.The levels of luxS and pfs mRNA were analyzed using real-time PCR.【Result】 The results showed that the level of AI-2 was consistent with the level of luxS mRNA in different growth phases.AI-2 production and luxS mRNA by APEC was increased by supplementation of glucose,maltose,and NaCl,while the addition of sucrose was decreased.The transcription level of luxS was correlated to the level of AI-2 production,while the transcription level of pfs did not correlate with the level of AI-2 production.【Conclusion】 The level of transcription of luxS is highly correlated with the level of AI-2 production,while the level of transcription of pfs does not correlate with the level of AI-2 production.Glucose,maltose and NaCl accelerate the synthesis of AI-2.