The proteome of Salmonella Typhimurium grown under in vivo‐mimicking conditions

Abstract

To successfully infect a host, it is a prerequisite for enteric pathogens such as Salmonella enterica serovar Typhimurium to adapt to their environment, in casu the gastrointestinal tract. The adoption of an appropriate lifestyle is triggered by environmental signals such as the low oxygen availability and high osmolarity prevalent in the gut. In order to gain more insight in the changes that are induced when S. Typhimurium is adapting to these particular conditions, we used 2-D DIGE technology to investigate the combined effect of low oxygen tension and high osmolarity on the proteome of S. Typhimurium SL1344 compared to standard laboratory conditions. As a validation of the 2-D DIGE technique, preferential protein labeling by the Cy-dyes was assessed and proved to be negligible. The differentially expressed proteins identified reflect very well the applied culture conditions. Furthermore, reported transcriptional changes and observed changes at the translational level show overlap. Among the metabolic processes that are upregulated under in vivo-mimicking conditions are anaerobic fumarate respiration and the utilization of 1,2-propanediol. We also provide evidence that S. Typhimurium expresses an arginine deiminase pathway for the catabolism of L-arginine. The increased activity of this pathway was biochemically validated. Finally, also proteins involved in quorum sensing and virulence are differentially expressed under in vivo-mimicking conditions. These conditions offer possibilities as a simplified model system for the host environment given the high overlap of identifications in our study and reported genuine in vivo studies, respectively.

Host Hydrogen Rather than That Produced by the Pathogen Is Important for Salmonella enterica Serovar Typhimurium Virulence

“…Recent results from Craig and coworkers (25) highlight the importance of aerobic respiration for host colonization; this would explain why a strictly anaerobic process such as the FHL/H 2 evolution is not important in vivo. FHL and associated H 2 production could be useful in other environments or within other hosts, as the metabolic flexibility of Salmonella is becoming more appreciated (37)(38)(39)(40). Our results suggest that evolution of H 2 by the activity of Hyc is not a requirement for either the virulence or the gut survival or fecal transmission of S. Typhimurium.…”

Integrating multiple ‘omics’ analysis for microbial biology: application and methodologies

“…2D-PAGE was first introduced in 1975(O'Farrell, 1975, and typically allows the detection of only a few hundred proteins after their separation, thereby covering only 'low-complexity' proteomes. With recent application of various fluorescent dyes in this approach, such as 2D fluorescence difference gel electrophoresis (2D DIGE), the coverage and sensitivity of gel-based protein analysis have been significantly improved (Sonck et al, 2009); however, it is still not compatible with gel-free proteomics techniques that can detect several thousand proteins of large dynamic ranges in a single run and that can also provide better detection for low-abundance proteins and insoluble membrane-spanning proteins (Wolff et al, 2006). Even with some improvement, currently neither the 2D-PAGE nor the LC-MS/MS approach is close to saturating identifications in even small bacterial proteomes: typically only 20-40 % of the proteome can be detected, and these are identification approaches and do not provide quantitative information.…”

Expression of STM4467 -Encoded Arginine Deiminase Controlled by the STM4463 Regulator Contributes to Salmonella enterica Serovar Typhimurium Virulence

“…The ADI pathway of S. Typhimurium appears to be functional, because the expression of the putative ADI cluster increased OTC activity (43). In the present study, we investigated the role of the ADI system in S. Typhimurium pathogenesis.…”