Enhanced heterogeneity of rpoB in Mycobacterium tuberculosis found at low pH.
Enhanced heterogeneity of rpoB in Mycobacterium tuberculosis found at low pH.
复制标题
低 pH 条件下结核分枝杆菌中 rpoB 的异质性增强。
DOI：
10.1093/jac/dkp125
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Timothy D McHugh
中科院分区：
文献类型：
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作者：
C. Jenkins;Joanna Bacon;Jon C. Allnutt;Kim A. Hatch;A. Bose;D. O’Sullivan;C. Arnold;S. Gillespie;Timothy D McHugh
目标
OBJECTIVES
The aim of this study was to gain an insight into the molecular mechanisms of the evolution of rifampicin resistance in response to controlled changes in the environment.
METHODS
We determined the proportion of rpoB mutants in the chemostat culture and characterized the sequence of mutations found in the rifampicin resistance-determining region of rpoB in a steady-state chemostat at pH 7.0 and 6.2.
RESULTS
The overall proportion of rpoB mutants of strain H37Rv remained constant for 37 days at pH 7.0, ranging between 3.6 x 10(-8) and 8.9 x 10(-8); however, the spectrum of mutations varied. The most commonly detected mutation, serine to leucine mutation at codon 531 (S531L), increased from 40% to 89%, while other mutations (S531W, H526Y, H526D, H526R, S522L and D516V) decreased over the 37 day sampling period. Changing the pH from 7.0 to 6.2 did not significantly alter the overall proportion of mutants, but resulted in a decrease in the percentage of strains harbouring S531L (from 89% to 50%) accompanied by an increase in the range of different mutations from 4 to 12.
CONCLUSIONS
The data confirm that the fitness of strains with the S531L mutation is greater than that of strains containing other mutations. We also conclude that at low pH the environment is permissive for a wider spectrum of mutations, which may provide opportunities for a successful mutant to survive.
DOI：
10.1054/tuld.1998.0002
发表时间：
1998-01-01
期刊：
Tubercle and Lung Disease
影响因子：
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作者：
Ramaswamy, S.;Musser, James M.
通讯作者：
Musser, James M.