High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

Abstract

Lactobacillus sanfranciscensis is a Gram-positive lactic acid bacterium used in food biotechnology. It is necessary to investigate many aspects of a model organism to elucidate mechanisms of stress response, to facilitate preparation, application and performance in food fermentation, to understand mechanisms of inactivation, and to identify novel tools for high pressure biotechnology. To investigate the mechanisms of the complex bacterial response to high pressure we have analyzed changes in the proteome and transcriptome by 2-D electrophoresis, and by microarrays and real time PCR, respectively. More than 16 proteins were found to be differentially expressed upon high pressure stress and were compared to those sensitive to other stresses. Except for one apparently high pressure-specific stress protein, no pressure-specific stress proteins were found, and the proteome response to pressure was found to differ from that induced by other stresses. Selected pressure-sensitive proteins were partially sequenced and their genes were identified by reverse genetics. In a transcriptome analysis of a redundancy cleared shot gun library, about 7% of the genes investigated were found to be affected. Most of them appeared to be up-regulated 2-to 4-fold and these results were confirmed by real time PCR. Gene induction was shown for some genes up-regulated at the proteome level (clpL/groEL/rbsK), while the response of others to high hydrostatic pressure at the transcriptome level seemed to differ from that observed at the proteome level. The up-regulation of selected genes supports the view that the cell tries to compensate for pressure-induced impairment of translation and membrane transport.

An Approach to the Regioselective Diamination of Conjugated Di‐ and Trienes

“…More precisely, GrpE is a co‐chaperone working as a nucleotide exchange factor for DnaK (a heat shock protein belonging to the Hsp70 family) and it activates the DnaK ATPase activity. It is well known that the basal expression level of both GroEL and GrpE is enhanced by environmental stress 47–50. Therefore, the present results support the idea that the Se(IV) supplementation is a stressing event for L. reuteri Lb2 BM.…”

High-pressure processing – effects on microbial food safety and food quality

“…Pressure treatment of microbial cells induces many changes in the bacterial cell, including inhibition of key enzymes, inhibition of protein synthesis, alterations in cell morphology and the cell membrane, as well as affecting the genetic mechanisms of the microorganism such as disruption of transcription and translation and cellular functions responsible for survival and reproduction (Patterson, 1999; Murchie et al , 2005; Torres & Velazquez, 2005; Vogel et al , 2005; Huppertz et al , 2006; Abe, 2007). Bacterial membrane damage has multiple effects, causing leakage of cellular material through the inner and outer membranes as well as nutrient uptake and disposal of cell waste, as seen in studies reporting increased sensitivity to sodium chloride (Chilton et al , 1997) and uptake of ethidium bromide and propidium iodide (Mackey et al , 1995; Ritz et al , 2001).…”

“…Microarray and proteome analysis has yielded valuable insight into possible genes or proteins that seem to be involved in conferring HPP resistance or survival. Such work has mainly concentrated on food pathogens such as E. coli (Ishii et al , 2005; Malone et al , 2006), Listeria monocytogenes (Bowman et al , 2006) and lactic acid bacteria such as Lactobacillus sanfranciscensis (Vogel et al , 2005). These studies and others (Aertsen et al , 2004a, b, 2005) have revealed that HPP treatment induces, among others, oxidative stress, heat‐ and cold‐stress responses, an SOS response, up‐regulation of genes for chemotaxis, phosphotransferase systems, flagellar systems and genes involved in cell elongation and septum development.…”

Lactic acid bacteria stress response to preservation processes in the beverage and juice industry

“…Lactic acid bacteria stress response to preservation processes Table1. Response mechanisms of LAB to various stress conditions encountered during food processing and the major stress proteins or enzymes involved in the response (adapted from Ananta & Knorr, 2004, Pavlovic et al, 2005Jofre et al, 2007;Franz & Holzapfel, 2011;Mota et al, 2013) .…”