Journal of Microbiology

Research Support, Non-U.S. Gov't

Protein Expression Analysis of Halobacillus dabanensis D-8T Subjected to Salt Shock: De Qin Feng , Bo Zhang , Wei Dong Lu , Su Sheng Yang; J. Microbiol. 2006;44(4):369-374.; DOI: https://doi.org/2418 [pii]

Abstract: To investigate the mechanism of salt tolerance of gram-positive moderately halophilic bacteria, two-dimensional gel electrophoresis (2-D PAGE) was employed to achieve high resolution maps of proteins of Halobacillus dabanensis D-8T. Approximately 700 spots of proteins were identified from these 2-D PAGE maps. The majority of these proteins had molecular weights between 17.5 and 66 kDa, and most of them were distributed between the isoelectric points (pI) 4.0 and 5.9. Some protein spots were distributed in the more acidic region of the 2-D gel (pI <4.0). This pattern indicated that a number of proteins in the strain D-8T are acidic. To understand the adaptation mechanisms of moderately halophilic bacteria in response to sudden environmental changes, differential protein profiles of this strain were investigated by 2-D PAGE and ImagemasterTM 2D Platinum software after the cells were subjected to salt shock of 1 to 25% salinity for 5 and 50 min. Analysis showed 59 proteins with an altered level of expression as the result of the exposure to salt shock. Eighteen proteins had increased expression, 8 proteins were induced, and the expression of 33 proteins was down-regulated. Eight of the up-regulated proteins were identified using MALDI-TOF/MS and MASCOT, and were similar to proteins involved in signal transduction, proteins participating in energy metabolism pathways and proteins involved in stress.

Journal Article

Proteomic Analysis of Protein Expression in Streptococcus pneumoniae in Response to Temperature Shift: Myoung-Ro Lee , Song-Mee Bae , Tong-Soo Kim , Kwang-Jun Lee; J. Microbiol. 2006;44(4):375-382.; DOI: https://doi.org/2417 [pii]

Abstract: From its initial colonization to causation of disease, Streptococcus pneumoniae has evolved strategies to cope with a number of stressful in vivo environmental conditions. In order to analyze a global view of this organism’s response to heat shock, we established a 2-D electrophoresis proteome map of the S. pneumoniae D39 soluble proteins under in vitro culture conditions and performed the comparative proteome analysis to a 37 to 42°C temperature up-shift in S. pneumoniae. When the temperature of an exponentially growing S. pneumoniae D39 culture was raised to 42°C, the expression level of 25 proteins showed changes when compared to the control. Among these 25 proteins, 12 were identified by MALDI-TOF and LC-coupled ESI MS/MS. The identified proteins were shown to be involved in the general stress response, energy metabolism, nucleotide biosynthesis pathways, and purine metabolism. These results provide clues for understanding the mechanism of adaptation to heat shock by S. pneumoniae and may facilitate the assessment <br>of a possible role for these proteins in the physiology and pathogenesis of this pathogen.

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