Proteome analysis of heat shock protein expression in Pseudomonas alcaligenes NCIMB 9867 in response to gentisate exposure and elevated growth temperature

Abstract

Pseudomonas alcaligenes NCIMB 9867 (strain P25X) degrades xylenols and cresols via the gentisate pathway. P25X expresses two isofunctional gentisate 1,2-dioxygenases (GDO I and GDO II). The expression of both GDOs was not detected when P25X cells were grown at 42 degrees C, even in the presence of gentisate. A total of 19 heat shock proteins (Hsps) belonging to the Hsp100, Hsp90, Hsp70, Hsp60, Hsp45, and small heat shock protein (sHsp) families were identified among the protein spots that were either newly detected or were expressed at levels of at least twofold higher when P25X cells were cultured at 32 or 42 degrees C in the presence and absence of gentisate. Among these, 16 Hsps were commonly expressed at 42 degrees C. Two additional Hsps (H5 and H13) from the Hsp90 and Hsp60 families, respectively, were expressed only when P25X cells were grown at 42 degrees C and in the presence of gentisate. A protein of the sHsp (H16) family was expressed only in the presence of gentisate at 32 degrees C but not at 42 degrees C. The GroEL chaperonins of the Hsp60 family comprised the largest group of Hsps identified and exhibited high level of expression at 42 degrees C following gentisate exposure.

Bacterial consortium proteomics under 4‐chlorosalicylate carbon‐limiting conditions

“…Concerning HpaG, it presents 43.5% aminoacid sequence identity to 4-hydroxyphenylacetate degradation isomerase (gi)83717800), an enzyme related to protocatechuate and gentisate catabolic pathways [19]. The presence of general stress response proteins like the universal stress protein UspA (protein spot 92), the chaperonin subunits GroEL (protein spot 99), and Cpn10 (protein spot 106), the elongation factors EF-Tu and EF-Ts (protein spots 16 and 34, respectively), oxidative stress response proteins such as superoxide dismutase (SOD as two isoforms, protein spots 59 and 60, respectively), alkylhydroperoxide reductase C (AhpC two isoforms, protein spots 54 and 55), and NTP pyrophosphohydrolase (protein spot 94) indicate that culturing conditions represent a stress to the bacterial culture as it has been shown before for P. putida KT2440 [18,20], P. putida S12 [21], and Pseudomonas alcaligenes NCIMB 9867 [22].…”

“…Contradictorily, EF-Tu has been reported to be upregulated in P. putida DOT-T1E and downregulated in P. putida S12 under toluene stress [21,42]. Finally, P. Alcaligenes NCIMB 9867 showed upregulation of EF-Tu under exposure to gentisate [22]. Since these effects were not observed in pure cultures of strain MT1, it may well be possible to argue that the presence of strain MT3 influences strain MT1 beyond variations in upper degradative pathways involving cell stress behavior.…”

Biodegradation: gaining insight through proteomics

“…In forest leachate, the number of proteins that originated from plants, fungi and vertebrates was approximately twice the number in the sampled lake water. Environmental proteomics can also detect expressions of proteins in a microbial community and provides critical insights into the important cellular activities with temporal and spatial environmental resolutions (Uchiyama et al 1999;Cho et al 2000;Sharma et al 2006;Zhao et al 2007). Such information not only yield useful biomarker proteins for environmental bioremediation, but also help to build up a proteomic databank to enable better understanding of the catalytic roles of microorganisms.…”

Insights into environmental bioremediation by microorganisms through functional genomics and proteomics

“…Zhao et al [43] investigated the expression of heat shock proteins in P. alcaligenes P25X in response to elevated temperature and gentisate exposure. When P25X cells were cultured at 32 or 427C in the presence and absence of gentisate as the aromatic inducer, 19 Hsp were identified from protein spots in 2-D gels that were either newly synthesized or were expressed at levels that were at least twofold higher.…”