【摘要】 目的比较El Tor型霍乱弧菌流行株与非流行株两类菌株在甘露醇发酵实验中甘露醇转运相关基因转录水平差异的普遍性,探索两类菌株发酵快慢的机理。方法对10株非流行株(快发酵菌株)和10株流行株(慢发酵菌株)在甘露醇发酵过程中的生长曲线变化进行检测,采用荧光实时定量PCR检测两类菌株PTS操纵子中mtlCBA基因的转录水平并比较其差异。结果在甘露醇发酵实验第4小时非流行株出现阳性反应时,非流行株整体生长趋势较流行株迅速,但单个菌株生长速度有快有慢;第8小时流行株出现阳性反应时,其生长高于非流行株。实验第1、2小时,非流行株mtlCBA的mRNA转录水平高于流行株;实验第4、8小时,流行株mtlCBA的mRNA转录水平高于非流行株。结论霍乱弧菌两类菌株甘露醇发酵实验中甘露醇PTS操纵子转录差异应是流行株和非流行株差异的重要特征,直接导致两类菌株甘露醇发酵快慢。生长菌量对快慢发酵不是主要影响因素。更多还原

【Abstract】 Objective To compare the transcription difference of the mannitol PTS genes between epidemic and non-epidemic strains of Vibrio cholerae El Tor in mannitol ferment tests.Methods Growth curves of 10 epidemic strains(slow-ferment) and 10 non-epidemic strains(rapid-ferment) of Vibrio cholerae were detected in the process of fermentation test,and the transcriptional level of mannitol PTS operon of these strains were determined with quantitative reverse-transcriptional PCR.Results After 4 hours of test,the non-epidemic strains became positive and the average growth density of the non-epidemic strains was higher than that of the epidemic strains;however,some were still lower than the epidemic strains.In contrast,at the eighth hour oftest,when epidemic strains got positive,they showed higher average growth density.Compared to the epidemic strains,the transcription of mannitol PTS genes of the non-epidemic strains were much more active at the 1st and 2nd hour and were lower at the 4th and 8th hour.Conclusions The difference of mannitol PTS operon transcription level should be an important feature to identify the epidemic and non-epidemic strains of Vibrio cholerae,which directly influences the mannitol fermentation rate during the test.The growth rate is not a key factor that affect such difference.更多还原