Surviving the Acid Test: Responses of Gram-Positive Bacteria to Low pH

Cotter, Paul D.; Hill, Colin

doi:10.1128/mmbr.67.3.429-453.2003

Cited by 996 publications

(856 citation statements)

References 272 publications

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“…Depending on the species, bacteria can induce several systems to counteract a drop in the internal pH when encountering low pH stress. Among others, these include proton pumps, several decarboxylases (lysine, glutamate, and arginine), the production of urease, arginine deiminase, chaperones (e.g., DnaK and GroELS), and sigma factor (SigB, SigM, and RpoS)-mediated responses (5,6,14,31,67). However, the importance of low-pH stress response systems in weak-acid resistance development remains unclear.…”

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confidence: 99%

Transcriptome Analysis of Sorbic Acid-Stressed Bacillus subtilis Reveals a Nutrient Limitation Response and Indicates Plasma Membrane Remodeling

et al. 2008

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The weak organic acid sorbic acid is a commonly used food preservative, as it inhibits the growth of bacteria, yeasts, and molds. We have used genome-wide transcriptional profiling of Bacillus subtilis cells during mild sorbic acid stress to reveal the growth-inhibitory activity of this preservative and to identify potential resistance mechanisms. Our analysis demonstrated that sorbic acid-stressed cells induce responses normally seen upon nutrient limitation. This is indicated by the strong derepression of the CcpA, CodY, and Fur regulon and the induction of tricarboxylic acid cycle genes, SigL-and SigH-mediated genes, and the stringent response. Intriguingly, these conditions did not lead to the activation of sporulation, competence, or the general stress response. The fatty acid biosynthesis (fab) genes and BkdR-regulated genes are upregulated, which may indicate plasma membrane remodeling. This was further supported by the reduced sensitivity toward the fab inhibitor cerulenin upon sorbic acid stress. We are the first to present a comprehensive analysis of the transcriptional response of B. subtilis to sorbic acid stress.

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Transcriptome Analysis of Sorbic Acid-Stressed Bacillus subtilis Reveals a Nutrient Limitation Response and Indicates Plasma Membrane Remodeling

et al. 2008

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“…The most commonly encountered stresses in foods are high or low temperature, high salt, and low pH, and the stress response to each of these factors has been characterized in some detail for important food-borne pathogens, such as Salmonella spp., E. coli O157:H7, and Listeria monocytogenes (6,7). However, a number of new techniques for food preservation are emerging that make use of other types of stress.…”

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confidence: 99%

Heat Shock Protein-Mediated Resistance to High Hydrostatic Pressure in Escherichia coli

Aertsen

Vanoirbeek

Spiegeleer

et al. 2004

Appl Environ Microbiol

133

113

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A random library of Escherichia coli MG1655 genomic fragments fused to a promoterless green fluorescent protein (GFP) gene was constructed and screened by differential fluorescence induction for promoters that are induced after exposure to a sublethal high hydrostatic pressure stress. This screening yielded three promoters of genes belonging to the heat shock regulon (dnaK, lon, clpPX), suggesting a role for heat shock proteins in protection against, and/or repair of, damage caused by high pressure. Several further observations provide additional support for this hypothesis: (i) the expression of rpoH, encoding the heat shock-specific sigma factor 32 , was also induced by high pressure; (ii) heat shock rendered E. coli significantly more resistant to subsequent high-pressure inactivation, and this heat shock-induced pressure resistance followed the same time course as the induction of heat shock genes; (iii) basal expression levels of GFP from heat shock promoters, and expression of several heat shock proteins as determined by two-dimensional sodium dodecyl sulfatepolyacrylamide gel electrophoresis of proteins extracted from pulse-labeled cells, was increased in three previously isolated pressure-resistant mutants of E. coli compared to wild-type levels.

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“…For study of growth kinetics under acid induced stress condition, M. aurum culture was overgrown in MB7H9 media (pH 6.5) for 3-4 days till late exponential phase [optical density 1.8-2.0 (A 600 )]. Cells were pre-adapted (by overgrowth) before subjecting them to stress conditions, as pre-adaptation is considered to be an important feature for survival under acid induced stress [17]. Stationary phase cells were washed twice with PBST to remove any traces of exhausted media.…”

Section: Cell Viability Under Acid Induced Stress Conditionsmentioning

confidence: 99%

Mycobacterium aurum is Unable to Survive Mycobacterium tuberculosis Latency Associated Stress Conditions: Implications as Non-suitable Model Organism

2016

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Mycobacterium tuberculosis manages to remain latent in the human body regardless of extensive chemotherapy. Complete eradication of tuberculosis (TB) requires treatment strategies targeted against latent form of infection, in addition to the current regimen of antimycobacterials. Many in vitro and in vivo models have been proposed to imitate latent TB infection, yet none of them is able to completely mimic latent infection state of M. tuberculosis. Highly infectious nature of the pathogen requiring BSL3 facilities and its long generation time further add to complications. M. aurum has been proposed as an important model organism for high throughput screening of drugs and exhibits high genomic similarity with that of M. tuberculosis. Thus, the present study was undertaken to explore if M. aurum could be used as a surrogate organism for studies related to M. tuberculosis latent infection. M. aurum was subjected to in vitro conditions of oxygen depletion, lack of nutrients and acidic stress encountered by latent M. tuberculosis bacteria. CFU count of M. aurum cells along with any change in cell shape and size was recorded at regular intervals during the stress conditions. M. aurum cells were unable to survive for extended periods under all three conditions used in the study. Thus, our studies suggest that M. aurum is not a suitable organism to mimic M. tuberculosis persistent infection under in vitro conditions, and further studies are required on different species for the establishment of a fast growing species as a suitable model for M. tuberculosis persistent infection.

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Surviving the Acid Test: Responses of Gram-Positive Bacteria to Low pH

Cited by 996 publications

References 272 publications

Transcriptome Analysis of Sorbic Acid-Stressed Bacillus subtilis Reveals a Nutrient Limitation Response and Indicates Plasma Membrane Remodeling

Transcriptome Analysis of Sorbic Acid-Stressed Bacillus subtilis Reveals a Nutrient Limitation Response and Indicates Plasma Membrane Remodeling

Heat Shock Protein-Mediated Resistance to High Hydrostatic Pressure in Escherichia coli

Mycobacterium aurum is Unable to Survive Mycobacterium tuberculosis Latency Associated Stress Conditions: Implications as Non-suitable Model Organism

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