摘要
为探索大肠杆菌O157∶H7对粪肠球菌N9分离株生长特性的影响及15种毒力基因在不同生长时期的应答情况,本研究将粪肠球菌N9、大肠杆菌O157∶H7单独培养和混合培养后分别计数菌株菌落总数,绘制生长曲线,根据生长曲线4个特定的时间点,分别提取其mRNA,反转录后利用荧光定量PCR方法检测15种毒力基因的转录水平。结果显示:混合培养与单独培养相比,粪肠球菌最高菌体浓度增加4 200多倍;两菌混合培养时,大肠杆菌整体促进了粪肠球菌15种毒力基因的转录,仅psr和atn在4个生长期中一直比单独培养时高,ebpA、ebpB、ebpR、rnjB、frsA、frsB除在稳定前期较单独培养时表达量低,其余3个时期均较高;而GelE和SprE除在对数中期和稳定期,其他时期均较单独培养时表达量低。稳定期ebpB和frsA表达量分别较单独培养高154.56倍和144.37倍,其次是对数后期ebpC,其表达量较单独培养时高110.35倍。实验结果表明:共培养时大肠杆菌能明显促进肠球菌的生长及其相关毒力基因的转录。
To explore the influence of Escherichia coli O157：H7 co-incubating to Enterococcus faecalis N9 on the growth traits and expression of 15 virulence genes of E.faecalis at various growth phases, the E.coli and E.faecalis were solely or co-incubated, respectively, then the bacteria growth curves were established based on the bacteria counting, and the mRNA transcription levels of 15 virulence genes from E.faecalis were detected at different time points by real-time PCR. The results showed that the concentration of E.faecalis increased by 4,200-times comparing with single incubation. While the transcription levels of 15 virulence genes from E.faecalis increased when co-incubated with E.coli, but the levels varied among them. The expressions of psr and atn were consistently up-regulated at all the four growth phases, and ebpA, ebpB, ebpR, mj＇B, frsA and frsB decreased only at early stable phase, while the expressions of gelE and sprE were increased just at the middle log phase and the stable phase. Compared with single culture, the transcription levels of ebpB and frsA at stable phase increased by 154.56 and 144.37 times, respectively, and ebpC increased by 110.35 times at late log phase. The results suggested that E.coli was able to significantly enhance the growth of E.faecalis and transcription of relatively virulence genes in co-culture with E. coli.
出处
《中国预防兽医学报》
CAS
CSCD
北大核心
2016年第8期614-619,共6页
Chinese Journal of Preventive Veterinary Medicine
基金
河南省重大攻关项目(112101110100)
郑州市重点实验室基金资助项目(114PYZX509)
