Proteomic analysis of XXXX and its adaptability to stress.

@entity1131 @entity15135 @entity15133 @entity15134 @entity369 @entity855
BACKGROUND: @entity15133 ( @entity15134 ) occurs abundantly in a variety of ecosystems, including ecosystems that place the bacterium under stress. This study assessed the adaptability of @entity15134 by submitting it to nutritional and pH stresses and then analyzing protein expression using bi-dimensional electrophoresis (2-DE) and Maldi mass spectrometry. RESULTS: @entity15133 grew best in pH neutral, nutrient-rich medium (reference conditions); however, the total protein mass recovered from stressed bacteria cultures was always higher than the total protein mass recovered from our reference culture. The diversity of proteins expressed (repressed by the number of identifiable 2-DE spots) was seen to be highest in the reference cultures, suggesting that stress reduces the overall range of proteins expressed by @entity15134 . Database comparisons allowed 43 of the 55 spots subjected to Maldi mass spectrometry to be characterized as containing a single identifiable protein. Stress-related expression changes were noted for @entity15134 proteins related to the previously characterized bacterial proteins: DnaK, GroEL-2, Rhs, EF-Tu, EF-P; MCP, homogentisate 1,2-dioxygenase, @entity369 deiminase and the @entity855 synthase b-subunit protein as well as for the ribosomal protein subunits L1, L3, L5 and L6. The ability of @entity15134 to adapt its cellular mechanics to sub-optimal growth and protein production conditions was well illustrated by its regulation of ribosomal protein subunits. With the exception of the ribosomal subunit L3, which plays a role in protein folding and maybe therefore be more useful in stressful conditions, all the other @entity1131 were seen to have reduced expression in stressed cultures. Curiously, C. violeaceum cultures were also observed to lose their violet color under stress, which suggests that the @entity15135 pigment biosynthetic pathway is affected by stress. CONCLUSIONS: Analysis of the proteomic signatures of stressed @entity15134 indicates that nutrient-starvation and pH stress can cause changes in the expression of the @entity15134 receptors, transporters, and proteins involved with biosynthetic pathways, molecule recycling, energy production. Our findings complement the recent publication of the C. violeaceum genome sequence and could help with the future commercial exploitation of C. violeaceum.
