摘要
目的:探讨mig-14基因在伤寒沙门菌拮抗多黏菌素B杀伤作用中的机制。方法:根据伤寒沙门菌mig-14基因序列设计PCR特异性扩增引物,应用自杀质粒介导的同源重组方法制备伤寒沙门菌mig-14基因缺陷变异株;在弱酸性条件下对野生株和mig-14缺陷株做多黏菌素B杀伤试验,比较两种菌株对多黏菌素B的耐受情况。提取野生株和mig-14缺陷株的总RNA,对两个与脂多糖相关的基因(425和527基因)做RT-PCR实验,进一步证实是否受mig-14的上调。结果:成功制备伤寒沙门菌mig-14缺陷株。在弱酸性条件下mig-14缺陷株对多黏菌素B的敏感性比野生株稍高。RT-PCR结果显示425和527基因受mig-14的上调。结论:mig-14可能是一种调节基因,参与调节细菌对抗菌肽拮抗作用的过程。
Objective To study the role of mig-14 in the resistance to polymyxin B of Salmonella enterlca serovar Typhi. Method As the genomic information, two pairs of primera were designed at upper - and down - streams of the mig - 14 gene of S. enteriea serovar Typhi to amplify two homologous DNA fragments, the mig - 14 deleted mutant of S. enteriea serovar Typhi was prepared by homologous recombination mediated by suicide plasmid; Performed the polymyxin B sensitivity assay for wild strain, mig- 14 mutant and phoP mutant,then compared their resistance to polymyxin B; Extracted the total RNA of wild strain and mig- 14 mutant, then performed the RNA reverse transcription for two lipopolysaccharide - associated genes （425 and 527 genes ）. Results Successfully prepared a mig - 14 mutant and found that mig - 14 mutant was more and less sensitive to polymyxin B than wild strain and phoP mutant respectively at poor acid envi- ronment from the polymyxin B sensitivity assay. The two lipopolysaccharide - associated genes were down - regulated by mlg - 14 according to the results of RT- PCR. Conclusion mig - 14 may be a transcriptional regulator, may participates in the regulations of resistance to cationic antimicrobial peptides.
出处
《吉林医学》
CAS
2011年第4期633-637,共5页
Jilin Medical Journal
