The Mycobacterium smegmatis 'Proteome': Effect of Growth Phase on Total Protein Synthesis and on the Response to Heat Shock

SSA Research Bongi Audrey NTOLOSI 149 PAGES (47109 WORDS) Thesis
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Abstract

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.

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APA

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

MLA 8th

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.

MLA7

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 >.

Chicago

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