福氏志贺菌基因mdoD对细菌生长、耐热击及酸碱能力的影响

Effects of Gene mdoD on the Growth,Heat Shock and pH Tolerance of Shigella flexneri

本试验以福氏志贺菌和opgD突变体(敲除基因mdoD的福氏志贺菌)为出发菌株,研究了福氏志贺菌基因opgD在低渗和正常渗透压条件下,在标准培养基和洗菜水中对细菌生长、耐热击及耐酸碱能力的影响。试验结果表明:在标准培养基中,opgD突变体生长效率比福氏志贺菌低,提高渗透压后突变体与福氏志贺菌生长曲线相似;在不同的洗菜水中,opgD突变体生长曲线不同,其生长速率明显比福氏志贺菌慢,加盐提高渗透压之后,福氏志贺菌和opgD突变体对数生长期均提前;福氏志贺菌和opgD突变体的抗性试验结果表明:opgD突变体抗热击的能力比福氏志贺菌显著降低,而opgD突变体的耐碱能力却比福氏志贺菌更强。

The Shigellaflexnei wild type and the opgD mutant （gene mdoD was knocked out） were chosen in this study to explore the effects of gene mdoD of S. flexneri on the growth in the media and different vegetables＇ wash waters under normal and hypoosmotic conditions, heat shock and pH tolerance. The results showed that the growth rate of opgD mutant was lower than S. flexnei in media, while the S. flexnei and opgD mutant grew similarly between normal osmolarity and hypoosmotic media; opgD mutant grew differently according to different wash waters and significantly slower than the growth of S. flexnei, the S. flexnei and opgD mutant grew faster after adding salt to hypoosmotic wash waters. The gene mdoD deletion in S. flexneri increased significantly the growth at alkali condition, while the deletion of gene mdoD decreased the resistance to heat shock.