Primary Studies On The Genetic Stability And Proteome Of Mycobacterium Tuberculosis Rifampin-depending Strain

The dependence of Mycobacterium tuberculosis (Mtb) to anti-tuberculosis drugs, which means persisting using these drugs for clinical tuberculotherapy may not only induce invalid therapy, but stimulate the growth of pathogens and aggravate patient's condition under definite conditions, has become a new problem in achieving successful prevention and treatment to tuberculosis. Therefore the research of anti-tuberculosis drug-dependence is urgently needed.However the unstableness of the drug-dependence in reproduction creates a bottleneck for the research of it. In this study we accordingly selected Mtb rifampin-depending strains for continuous generation transfer experiment in vitro, and the results indicated the drug-dependence can be passed on stably during about 30 generations. The above-mentioned dependence-lost Mtb were resuspended and were inoculated through tail vein to infect mice, then treated the mice by rifampin gavage with different frequencies, and the restoration of drug-dependence of part Mtb was observed finally.Pulmonary tuberculosis caused by drug-depending Mtb have the features of severe symptom, multiple drug resistance, poor effect of tuberculotherapy and bad prognosis, and do harm to human health further more than common drug resistance cases. It's reported that the Mtb rifampin-depending strain and rifampin-resistant stain have almost the same high-frequency mutation point of rpoB gene, and the types and distribution of the two strains' DNA fingerprints are not significantly different, which demonstrate the variation of rifampin-depending strain is mainly phenotypic variation. Therefore the unique appearance of drug-dependence may only arise from the different gene expression. The following study was started from proteins, the 2-DE methods in proteomic analysis of Mtb were optimized firstly, and satisfactory 2-DE maps were obtained. Using this approach we identified 8 protein spots and acquired 7 classes of proteins in rifampin-depending strain whose expression were remarkable different comparing with rifampin-resistant strain. The 7 identified proteins are 3-oxoacyl-ACP synthase, chain A of Ag85B, ECH, STPK D, putative transferase, theβsubunit of SCOB and HSPX. And the molecular mechanism of drug-dependence was preliminarily discussed.We demonstrated the utility of comparative proteomic analysis for studying the protein profiling of drug-depending Mtb. These differentially expressed proteins provide materials for further investigation on the molecular mechanism of drug-dependence in Mtb.