As an initial step towards characterisation of the molecular processes that define the
phenotype of the mycobacterial stationary phase, the effect of growth phase of
Mycobacterium smegmatis on total protein synthesis and on the heat shock response was
investigated. De novo protein synthesis was monitored by labelling with 35 [S]methionine
and the protein expression profiles analysed using one- and/two-dimensional
polyacrylamide gel electrophoresis , autoradiography , and/or immunoblot analysis. The
ATP content of the culture was found to be a more accurate indicator that cells were
entering stationary phase than the number of colony forming units (CFU). A plateau in
the ATP growth curve preceded several stationary phase-induced events : a transitory
cessation in the increase in number of CFU ; a decrease in the rate of accumulation of the
cell division protein FtsZ; inhibition of the synthesis of 58 , 30.5 , and 20 kDa exponential
phase proteins; induction of the 48 , 46 , 32 , 31 , 25 , and 20 kDa stationary phase (postexponential
phase) proteins ; and the highest induction of the 95 kDa, 75 kDa (DnaK), 66
kDa ( GroEL ), and - 17 kDa (doublet) proteins in response to heat shock. Identification of
the stationary phase-induced proteins should enable their roles in the multigenic
processes that occur during transition into stationary phase to be determined.
The amino acid sequence of one of the - 17 kDa heat shock proteins (with an apparent
molecular weight of 16.8 kDa, named Hspl7-2) showed significant homology to open
reading frame 28 of M tuberculosis cosmid MTCY01B2. This is the first time a
functional characteristic has been assigned to this open reading frame , and it remains to
be seen if Hspl 7-2 represents a new family of heat shock proteins. Synthesis and
secretion of the antigen (Ag)-85 complex proteins was demonstrated for the first time in
M smegmatis. Heat shock resulted in increased release of Ag85A and Ag85B but not of
Ag85C in M smegmatis. No heat-induction of the Ag85 complex could be demonstrated
in My cobacterium bovis BCG. Whereas heat shock resulted in increased release of the 19
kDa lipoprotein antigen in both M bovis BCG and M tuberculosis H37Rv, its presence
in M smegmatis could not be demonstrated. This study presents an experimental
approach which may prove useful in investigating the effect of various environmental
stresses on the profile, and hence the function of secreted proteins.
SSA, R (2021). The Mycobacterium smegmatis 'Proteome': Effect of Growth Phase on Total Protein Synthesis and on the Response to Heat Shock. Afribary.com: Retrieved May 10, 2021, from https://afribary.com/works/the-mycobacterium-smegmatis-proteome-effect-of-growth-phase-on-total-protein-synthesis-and-on-the-response-to-heat-shock
Research, SSA. "The Mycobacterium smegmatis 'Proteome': Effect of Growth Phase on Total Protein Synthesis and on the Response to Heat Shock" Afribary.com. Afribary.com, 24 Apr. 2021, https://afribary.com/works/the-mycobacterium-smegmatis-proteome-effect-of-growth-phase-on-total-protein-synthesis-and-on-the-response-to-heat-shock . Accessed 10 May. 2021.
Research, SSA. "The Mycobacterium smegmatis 'Proteome': Effect of Growth Phase on Total Protein Synthesis and on the Response to Heat Shock". Afribary.com, Afribary.com, 24 Apr. 2021. Web. 10 May. 2021. < https://afribary.com/works/the-mycobacterium-smegmatis-proteome-effect-of-growth-phase-on-total-protein-synthesis-and-on-the-response-to-heat-shock >.
Research, SSA. "The Mycobacterium smegmatis 'Proteome': Effect of Growth Phase on Total Protein Synthesis and on the Response to Heat Shock" Afribary.com (2021). Accessed May 10, 2021. https://afribary.com/works/the-mycobacterium-smegmatis-proteome-effect-of-growth-phase-on-total-protein-synthesis-and-on-the-response-to-heat-shock