Osmoprotectants and cryoprotectants for Listeria monocytogenes

Bayles, Darrell O.; Wilkinson, Brian J.

doi:10.1046/j.1472-765x.2000.00646.x

Cited by 102 publications

(83 citation statements)

References 35 publications

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“…The function of glycine betaine as an osmoprotectant for microbial cells has been well documented (19); in addition, recent experiments with the food-borne pathogen Listeria monocytogenes demonstrate that it also confers chill protection (6,15,46). The growth experiments that we conducted (Fig.…”

Section: Vol 185 2003 General Stress Response and Cold Adaptation 4311mentioning

confidence: 76%

“…We noted that the induction of the general stress regulon is particularly important in a rather narrow temperature range close to 15°C, since there was no substantial growth difference between a SigB ϩ and a SigB Ϫ strain when the cells were cultivated at or above 16°C (data not shown). Glycine betaine has a well-established role in the osmoprotection of microbial cells (19), but additional experiments suggest a function for this compatible solute in chill stress protection as well (6,15,46). We therefore tested the influence of glycine betaine on the growth of the wild-type B. subtilis strain 168 and its isogenic sigB mutant at a low temperature.…”

Section: Resultsmentioning

confidence: 99%

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Chill Induction of the SigB-Dependent General Stress Response inBacillus subtilisand Its Contribution to Low-Temperature Adaptation

et al. 2003

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A variety of environmental and metabolic cues trigger the transient activation of the alternative transcription factor SigB of Bacillus subtilis, which subsequently leads to the induction of more than 150 general stress genes. This general stress regulon provides nongrowing and nonsporulated cells with a multiple, nonspecific, and preemptive stress resistance. By a proteome approach we have detected the expression of the SigB regulon during continuous growth at low temperature (15°C). Using a combination of Western blot analysis and SigB-dependent reporter gene fusions, we provide evidence for high-level and persistent induction of the sigB operon and the SigB regulon, respectively, in cells continuously exposed to low temperatures. In contrast to all SigB-activating stimuli described thus far, induction by low temperatures does not depend on the positive regulatory protein RsbV or its regulatory phosphatases RsbU and RsbP, indicating the presence of an entirely new pathway for the activation of SigB by chill stress in B. subtilis. The physiological importance of the induction of the general stress response for the adaptation of B. subtilis to low temperatures is emphasized by the observation that growth of a sigB mutant is drastically impaired at 15°C. Inclusion of the compatible solute glycine betaine in the growth medium not only improved the growth of the wild-type strain but rescued the growth defect of the sigB mutant, indicating that the induction of the general stress regulon and the accumulation of glycine betaine are independent means by which B. subtilis cells cope with chill stress.

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Section: Vol 185 2003 General Stress Response and Cold Adaptation 4311mentioning

confidence: 76%

Section: Resultsmentioning

confidence: 99%

Chill Induction of the SigB-Dependent General Stress Response inBacillus subtilisand Its Contribution to Low-Temperature Adaptation

et al. 2003

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“…They therefore also are referred to in the literature as chemical chaperones (13,15). The stabilizing effects of compatible solutes on macromolecules and biosynthetic processes probably contributes to their physiological functions as protectants against heat (13,23) and cold stress (3,22).…”

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confidence: 99%

Ectoine and Hydroxyectoine as Protectants against Osmotic and Cold Stress: Uptake through the SigB-Controlled Betaine-Choline- Carnitine Transporter-Type Carrier EctT from Virgibacillus pantothenticus

et al. 2011

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Virgibacillus pantothenticus has been shown to synthesize the compatible solute ectoine in response to high salinity or low growth temperature. We found that exogenously provided ectoine and hydroxyectoine also serve as protectants against these challenges. Transport studies with [ 14 C]ectoine revealed that both types of stress induced a high-affinity ectoine uptake activity in V. pantothenticus. By using an Escherichia coli mutant defective in osmoprotectant uptake systems, a functional complementation approach for osmostress resistance in the presence of ectoine was employed to retrieve a gene encoding an ectoine transporter from V. pantothenticus. The cloned gene (ectT) encodes a protein (EctT) that is a member of the BCCT (betaine-choline-carnitinetransporter) family of carriers. Osmoprotection assays demonstrated that the EctT carrier mediates the preferential import of ectoine and hydroxyectoine but also possesses minor uptake activities for the compatible solutes proline and glycine betaine. Northern blot analysis with RNA isolated from V. pantothenticus revealed that a rise in the external osmolality or a reduction in growth temperature strongly increased the transcription of the ectT gene. Primer extension analysis demonstrated that ectT was transcribed under these conditions from a SigB-type promoter. SigB is the master regulator of the general stress regulon of bacilli and provides protection to cells against various challenges, including high salinity and low temperature. Both the synthesis of ectoine and the EctT-mediated uptake of ectoine and hydroxyectoine are triggered by the same environmental cues, high salinity and cold stress, and thereby provide, in a concerted fashion, the protection of V. pantothenticus against these challenges.

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“…Growth rates of cultures (doubling times per hour of cultures in exponential growth) were calculated (2). Mid-exponential-phase cells were recovered by centrifugation at 8,000 ϫ g for 10 min at 4°C and washed three times with distilled water.…”

mentioning

confidence: 99%

Role of Branched-Chain Fatty Acids in pH Stress Tolerance in Listeria monocytogenes

Giotis

McDowell

Blair

et al. 2007

Appl Environ Microbiol

127

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In alkaline conditions, Listeria monocytogenes cells develop higher proportions of branched-chain fatty acids (FAs), including more anteiso forms. In acid conditions, the opposite occurs. Reduced growth of pH-sensitive mutants at adverse pH (5.0/9.0) was alleviated by the addition of 2-methylbutyrate (an anteiso-FA precursor), suggesting that anteiso-FAs are important in adaptation to adverse pH. The balance between anteiso-and iso-FAs may be more important than changes in the amounts and/or degrees of saturation of FAs in pH adaptation.Listeria monocytogenes can grow under a wide range of pH stress, i.e., 4.1 to 9.0 (38, 46), increasing its abilities to persist during food processing and attempts to decontaminate food-processing environments (15,(42)(43)(44)(45). It also has particularly impressive capacities to modulate its membrane lipids to maintain membrane fluidity and transport functions (10,40,41) in response to temperature (1), salt (7), and CO 2 /anaerobiotic (21) stress. Such capacities have been suggested to be related to its atypically high iso and anteiso, odd-numbered, branched-chain fatty acid (BCFA) content (1,20) and its ability to modulate the overall content and proportions of BCFAs, straight-chain FAs (SCFAs), and unsaturated FAs (22,23). For example, reductions in environmental temperatures lead to increases in the amount of ai15:0 present in L. monocytogenes cell membranes, while increases in environmental temperatures lead to reductions in the amounts of ai15:0 and other BCFAs present in membranes (1,14,32).Changes in FA profile have been associated with pH adaptation in Streptococcus mutans (16-18), Escherichia coli (5, 48), and Salmonella (24), Pseudomonas (31), and Bacillus species (23). However, little is known about pH stress-associated modulation of FAs in L. monocytogenes (21), the wider role of FA modulation in its responses to nonthermal stresses, or the cross-protection mechanisms which operate in this hardy pathogen (19,27,35,44).The aims of this study were to investigate the modulation of the FA profile of L. monocytogenes membranes in response to changes in environmental pH, investigate the effects of an exogenous BCFA precursor on the pH stress response of BCFA-deficient mutants (1, 49), and examine possible links between the prevalence of anteiso-BCFAs and the adaptation mechanism(s) of L. monocytogenes under adverse pH conditions. Modified brain heart infusion broth (MBHIB; Difco Laboratories, Sparks, MD), suitable for adverse-pH studies, was prepared to pH 5.0, 5.5, and 6.0 in 2 M disodium phosphate Washed cells from mid-exponential-phase cultures of L. monocytogenes 10403S, an isogenic sigB null mutant (3), and isogenic non-BCFA-producing cld-1 and cld-2 mutants (1, 49) were inoculated into preheated (30°C) 100-ml volumes of the buffered MBHIB and grown (30°C/200 rpm) to an optical density at 600 nm of 0.5 to 0.6. Growth rates of cultures (doubling times per hour of cultures in exponential growth) were calculated (2). Mid-exponential-phase cells were recovered by centrif...

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Osmoprotectants and cryoprotectants for Listeria monocytogenes

Cited by 102 publications

References 35 publications

Chill Induction of the SigB-Dependent General Stress Response inBacillus subtilisand Its Contribution to Low-Temperature Adaptation

Chill Induction of the SigB-Dependent General Stress Response inBacillus subtilisand Its Contribution to Low-Temperature Adaptation

Ectoine and Hydroxyectoine as Protectants against Osmotic and Cold Stress: Uptake through the SigB-Controlled Betaine-Choline- Carnitine Transporter-Type Carrier EctT from Virgibacillus pantothenticus

Role of Branched-Chain Fatty Acids in pH Stress Tolerance in Listeria monocytogenes

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