Open AccessProtein synthesis is shutdown in dormant Mycobacterium tuberculosis and is reversed by oxygen or heat shock
Author(s) -
Hu Yan Min,
Butcher Philip D,
Sole Kath,
Mitchison D.A,
Coates A.R.M
Publication year - 1998
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1998.tb12813.x
Subject(s) - microaerophile , anaerobic exercise , biology , mycobacterium tuberculosis , bacteria , microbiology and biotechnology , incubation , bacilli , oxygen , methionine , protein biosynthesis , anaerobic bacteria , heat shock protein , biochemistry , tuberculosis , chemistry , amino acid , physiology , medicine , genetics , organic chemistry , pathology , gene
Oxygen‐limiting conditions are critical to the survival of the bacteria in tuberculosis. Mycobacterium tuberculosis can survive anaerobiosis in vitro for long periods of time only after a gradual transition to a microaerophilic stationary phase. The underlying mechanism behind stationary phase adaption needs to be elucidated. The protein profiles of Mycobacterium tuberculosis during long‐term stationary phase growth and under strict anaerobic incubation were monitored by [ 35 S]methionine labelling, SDS‐PAGE and fluorography. These experiments have established that protein synthesis gradually decreased over 50 days in the long‐term stationary phase cultures which were considered to be microaerophilic. There was an 80% linear decrease in the level of total protein synthesis during the first 40 days of microaerophilic growth and then the rate of protein synthesis faded quickly. For the first time we have shown that total protein synthesis shutdown occurred when bacilli were incubated under further anaerobic conditions. Viability, estimated by cfu counts, remained constant during stationary phase growth and under anaerobic incubation. Furthermore, when oxygen was introduced into the anaerobic culture, protein synthesis restarted. Also heat shock at 45°C, 48°C and 50°C rapidly induced protein synthesis in stationary and anaerobic cultures. These data indicate that dormant bacteria shut down protein synthesis but remain responsive to specific stimuli which restore protein synthesis. In addition the dormant bacilli induced by anaerobiosis developed more heat resistance than non‐dormant organisms.