scholarly journals Listeria monocytogenes 10403S Arginine Repressor ArgR Finely Tunes Arginine Metabolism Regulation under Acidic Conditions

2017 ◽  
Vol 8 ◽  
Author(s):  
Changyong Cheng ◽  
Zhimei Dong ◽  
Xiao Han ◽  
Jing Sun ◽  
Hang Wang ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Arginine Metabolism ◽  
Metabolism Regulation ◽  
Arginine Repressor ◽  
Acidic Conditions

Growth, Inhibition, and Survival of Listeria monocytogenes as Affected by Acidic Conditions

1990 ◽  
Vol 53 (8) ◽  
pp. 652-655 ◽  
Author(s):  
DONALD E. CONNER ◽  
VIRGINIA N. SCOTT ◽  
DANE T. BERNARD
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Growth Inhibition ◽  
Propionic Acid ◽  
Cell Populations ◽  
Growth And Survival ◽  
Viable Cells ◽  
Acidic Conditions ◽  
Ph Range ◽  
Lactic Acids

Growth and survival of four strains of Listeria monocytogenes under acidic conditions were investigated. Tryptic soy broth with yeast extract (TSBYE) was acidified with acetic, citric, hydrochloric, lactic, or propionic acid to pH 4.0–6.0, inoculated with L. monocytogenes and incubated at 30 or 4°C. The minimum test pH at which L. monocytogenes did not grow (inhibitory pH) was determined for each acid. In the pH range tested, this inhibitory pH was 5.0 for propionic acid, 4.5 for acetic and lactic acids, and 4.0 for citric and hydrochloric acids. All four strains gave similar results. Subsequent studies were conducted at 10 and 30°C to determine changes in cell populations in TSBYE adjusted to each inhibitory pH. Initial populations of viable cells (104 CFU/ml) were reduced to <10 CFU/ml within 1–3 weeks at 30°C, whereas at 10°C, L. monocytogenes survived for 11–12 weeks in acetic, citric, or propionic acid-adjusted media and for 6 weeks in media adjusted with hydrochloric or lactic acid. The concentration of undissociated lactic acid was 0.002 M at pH 4.5.

scholarly journals Lmo0036, an ornithine and putrescine carbamoyltransferase in Listeria monocytogenes, participates in arginine deiminase and agmatine deiminase pathways and mediates acid tolerance

Microbiology ◽  
2011 ◽  
Vol 157 (11) ◽  
pp. 3150-3161 ◽  
Author(s):  
Jianshun Chen ◽  
Changyong Cheng ◽  
Ye Xia ◽  
Hanxin Zhao ◽  
Chun Fang ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Foodborne Pathogen ◽  
Acid Tolerance ◽  
Arginine Deiminase ◽  
Transcriptional Level ◽  
Acidic Conditions ◽  
Acidic Environments ◽  
Agmatine Deiminase

Listeria monocytogenes is a foodborne pathogen causing listeriosis. Acid is one of the stresses that foodborne pathogens encounter most frequently. The ability to survive and proliferate in acidic environments is a prerequisite for infection. However, there is limited knowledge about the molecular basis of adaptation of L. monocytogenes to acid. Arginine deiminase (ADI) and agmatine deiminase (AgDI) systems are implicated in bacterial tolerance to acidic environments. Homologues of ADI and AgDI systems have been found in L. monocytogenes lineages I and II strains. Sequence analysis indicated that lmo0036 encodes a putative carbamoyltransferase containing conserved motifs and residues important for substrate binding. Lmo0036 acted as an ornithine carbamoyltransferase and putrescine carbamoyltransferase, representing the first example, to our knowledge, that catalyses reversible ornithine and putrescine carbamoyltransfer reactions. Catabolic ornithine and putrescine carbamoyltransfer reactions constitute the second step of ADI and AgDI pathways. However, the equilibrium of in vitro carbamoyltransfer reactions was overwhelmingly towards the anabolic direction, suggesting that catabolic carbamoyltransferase was probably the limiting step of the pathways. lmo0036 was induced at the transcriptional level when L. monocytogenes was subjected to low-pH stress. Its expression product in Escherichia coli exhibited higher catabolic carbamoyltransfer activities under acidic conditions. Consistently, absence of this enzyme impaired the growth of Listeria under mild acidic conditions (pH 4.8) and reduced its survival in synthetic human gastric fluid (pH 2.5), and corresponded to a loss in ammonia production, indicating that Lmo0036 was responsible for acid tolerance at both sublethal and lethal pH levels. Furthermore, Lmo0036 played a possible role in Listeria virulence.

Acid-Adapted Listeria monocytogenes Displays Enhanced Tolerance against the Lantibiotics Nisin and Lacticin 3147

1999 ◽  
Vol 62 (5) ◽  
pp. 536-540 ◽  
Author(s):  
WILLEM van SCHAIK ◽  
CORMAC G. M. GAHAN ◽  
COLIN HILL
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Listeria Monocytogenes ◽  
Bacterial Membrane ◽  
Straight Chain ◽  
Distinct Mode ◽  
Acid Adaptation ◽  
Lacticin 3147 ◽  
Acidic Conditions ◽  
Moderate Effect

Log-phase Listeria monocytogenes cells become tolerant to a variety of environmental stresses following acid adaptation at pH 5.5. We demonstrated that adapted cells also exhibit increased tolerance to nisin and, to a lesser extent, lacticin 3147. At nisin concentrations of 100 and 200 IU/ml the survival of acid-adapted cells was approximately 10-fold greater than nonadapted cells. However, acid adaptation had only a moderate effect on the tolerance of L. monocytogenes to lacticin 3147, a phenomenon that possibly reflects the distinct mode of action of this bacteriocin. Analysis of the fatty acid composition of the bacterial membrane indicated that straight-chain fatty acids C14:0 and C16:0 were significantly increased in acid-adapted cells while levels of C18:0 decreased. The results indicate that stress mechanisms that are induced in mildly acidic conditions provide protection against the antimicrobial action of bacteriocins. This increased resistance of acid-adapted L. monocytogenes could cause increased survival of this pathogen in food products in which nisin or other bacteriocins are used as preservatives.

scholarly journals Intracellular Accumulation of High Levels of γ-Aminobutyrate by Listeria monocytogenes 10403S in Response to Low pH: Uncoupling of γ-Aminobutyrate Synthesis from Efflux in a Chemically Defined Medium

2010 ◽  
Vol 76 (11) ◽  
pp. 3529-3537 ◽  
Author(s):  
Kimon-Andreas G. Karatzas ◽  
Orla Brennan ◽  
Sin�ad Heavin ◽  
John Morrissey ◽  
Conor P. O'Byrne
Keyword(s):  
Listeria Monocytogenes ◽  
Brain Heart Infusion ◽  
Defined Medium ◽  
Low Ph ◽  
Growth Media ◽  
Chemically Defined Medium ◽  
Extracellular Glutamate ◽  
Gaba Production ◽  
Mammalian Stomach ◽  
Acidic Conditions

ABSTRACT It is well established that the glutamate decarboxylase (GAD) system is central to the survival of Listeria monocytogenes at low pH, both in acidic foods and within the mammalian stomach. The accepted model proposes that under acidic conditions extracellular glutamate is transported into the cell in exchange for an intracellular γ-aminobutyrate (GABAi). The glutamate is then decarboxylated to GABAi, a reaction that consumes a proton, thereby helping to prevent acidification of the cytoplasm. In this study, we show that glutamate supplementation had no influence on either growth rate at pH 5.0 or survival at pH 2.5 when L. monocytogenes 10403S was grown in a chemically defined medium (DM). In response to acidification, cells grown in DM failed to efflux GABA, even when glutamate was added to the medium. In contrast, in brain heart infusion (BHI), the same strain produced significant extracellular GABA (GABAe) in response to acidification. In addition, high levels of GABAi (>80 mM) were found in the cytoplasm in response to low pH in both growth media. Medium-swap and medium-mixing experiments revealed that the GABA efflux apparatus was nonfunctional in DM, even when glutamate was present. It was also found that the GadT2D2 antiporter/decarboxylase system was transcribed poorly in DM-grown cultures while overexpression of gadD1T1 and gadD3 occurred in response to pH 3.5. Interestingly, BHI-grown cells did not respond with upregulation of any of the GAD system genes when challenged at pH 3.5. The accumulation of GABAi in cells grown in DM in the absence of extracellular glutamate indicates that intracellular glutamate is the source of the GABAi. These results demonstrate that GABA production can be uncoupled from GABA efflux, a finding that alters the way we should view the operation of bacterial GAD systems.

scholarly journals Listeria monocytogenes Sublethal Injury and Viable-but-Nonculturable State Induced by Acidic Conditions and Disinfectants

2021 ◽  
Author(s):  
Marianna Arvaniti ◽  
Panagiotis Tsakanikas ◽  
Vasiliki Papadopoulou ◽  
Artemis Giannakopoulou ◽  
Panagiotis Skandamis
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Viable But Nonculturable ◽  
Growth Capacity ◽  
Major Threat ◽  
Sublethal Injury ◽  
Nonculturable State ◽  
Acidic Conditions ◽  
Favorable Conditions ◽  
Viable But Nonculturable State

Sublethally injured and VBNC cells may evade detection, resulting in underestimation of a food product’s microbial load. Under favorable conditions, cells may regain their growth capacity and acquire new resistant characteristics, posing a major threat for public health.

scholarly journals Transcriptomic and Phenotypic Responses of Listeria monocytogenes Strains Possessing Different Growth Efficiencies under Acidic Conditions

2010 ◽  
Vol 76 (14) ◽  
pp. 4836-4850 ◽  
Author(s):  
John P. Bowman ◽  
Kim Jye Lee Chang ◽  
Terry Pinfold ◽  
Tom Ross
Keyword(s):  
Listeria Monocytogenes ◽  
Cell Envelope ◽  
Growth Efficiency ◽  
Potassium Sorbate ◽  
Good Growth ◽  
Acetate Anion ◽  
Acid Sensitivity ◽  
Acidic Conditions ◽  
Resistant Strains ◽  
Altered Cell

ABSTRACT In an experiment delineating aciduric strains, food and clinical Listeria monocytogenes isolates tended to produce the most biomass whereas ovine and avian strains produced comparatively less biomass when exposed to high levels of sodium diacetate (SD) and potassium sorbate. Compared to reference strains that exhibited greater acid sensitivity, representative food isolates with comparatively good growth capacities in the presence of 21 mM SD at pH 5.0 accumulated reduced levels of acetate anion and K+ ion. The aciduric nature of SD-resistant strains was also reflected by comparatively high tolerance to pH 2.4 (HCl) acid challenges, a property boosted by the presence of SD. Exposure to elevated levels of SD (21 mM SD at pH 5.0) was found to have broad effects on gene expression, as differentiated from effects caused by mildly acidic conditions (pH 5.0). SD-resistant strain FW04/0025 was more responsive to elevated SD, increasing the expression of 222 genes (>2-fold change [P < 0.05]), compared to the more sensitive EGD reference strain, which exhibited increases in expression of 112 genes. Key differences between the strains in relation to SD-enhanced transcripts were notably associated with the cell envelope, oxidative stress management, and intermediary metabolism. SD thus appears to differentially influence growth efficiency and survival of strains, under conditions relevant to acidic foods, that could be due to altered cell wall and metabolic phenotypes.

scholarly journals Functional γ-Aminobutyrate Shunt in Listeria monocytogenes: Role in Acid Tolerance and Succinate Biosynthesis

2012 ◽  
Vol 79 (1) ◽  
pp. 74-80 ◽  
Author(s):  
Conor Feehily ◽  
Conor P. O'Byrne ◽  
Kimon Andreas G. Karatzas
Keyword(s):  
Listeria Monocytogenes ◽  
Crude Protein ◽  
Tricarboxylic Acid Cycle ◽  
Acid Tolerance ◽  
Succinic Semialdehyde ◽  
Succinic Semialdehyde Dehydrogenase ◽  
Gaba Shunt ◽  
Content Type ◽  
Semialdehyde Dehydrogenase ◽  
Acidic Conditions

ABSTRACTListeria monocytogenes, the causative agent of human listeriosis, is known for its ability to withstand severe environmental stresses. The glutamate decarboxylase (GAD) system is one of the principal systems utilized by the bacterium to cope with acid stress, a reaction that produces γ-aminobutyrate (GABA) from glutamate. Recently, we have shown that GABA can accumulate intracellularly under acidic conditions, even under conditions where no extracellular glutamate-GABA exchange is detectable. The GABA shunt, a pathway that metabolizes GABA to succinate, has been described for several other bacterial genera, and the present study sought to determine whetherL. monocytogeneshas this metabolic capacity, which, if present, could provide a possible route for succinate biosynthesis inL. monocytogenes. Using crude protein extracts fromL. monocytogenesEGD-e, we show that this strain exhibits activity for the two main enzyme reactions in the GABA shunt, GABA aminotransferase (GABA-AT) and succinic semialdehyde dehydrogenase (SSDH). Two genes were identified as candidates for encoding these enzyme activities,argD(GABA-AT) andlmo0913(SSDH). Crude protein extracts prepared from a mutant lacking a functionalargDgene significantly reduced GABA-AT activity, while anlmo0913mutant lost all detectable SSDH activity. The deletion oflmo0913increased the acid tolerance of EGD-e and showed an increased accumulation of intracellular GABA, suggesting that this pathway plays a significant role in the survival of this pathogen under acidic conditions. This is the first report of such a pathway in the genusListeria, which highlights an important link between metabolism and acid tolerance and also presents a possible compensatory pathway to partially overcome the incomplete tricarboxylic acid cycle ofListeria.

scholarly journals Control of nitrogen homeostasis: intestinal arginine metabolism regulation according to protein supply.

2007 ◽  
Vol 21 (6) ◽  
Author(s):  
Gabrielle Ventura ◽  
Florian Sinico ◽  
Christophe Moinard ◽  
Luc Cynober ◽  
Jean‐Pascal De Bandt
Keyword(s):  
Arginine Metabolism ◽  
Metabolism Regulation ◽  
Protein Supply

scholarly journals Presence of GadD1 Glutamate Decarboxylase in Selected Listeria monocytogenes Strains Is Associated with an Ability To Grow at Low pH

2005 ◽  
Vol 71 (6) ◽  
pp. 2832-2839 ◽  
Author(s):  
Paul D. Cotter ◽  
Sheila Ryan ◽  
Cormac G. M. Gahan ◽  
Colin Hill
Keyword(s):  
Listeria Monocytogenes ◽  
Glutamate Decarboxylase ◽  
Low Ph ◽  
Strain Variation ◽  
Ph Stress ◽  
Genes Encoding ◽  
Acidic Conditions ◽  
The Creation ◽  
Isogenic Mutants ◽  
Acid Challenge

ABSTRACT The glutamate decarboxylase (GAD) system is critical to the survival of Listeria monocytogenes LO28 at low-pH stress (<pH 4.0). The GAD system classically involves two proteins, a glutamate decarboxylase enzyme coupled to a glutamate/γ-aminobutyrate antiporter, which results in the consumption of an intracellular proton for each glutamate entering the system. Uniquely among prokaryotes, some strains of L. monocytogenes, including strain LO28, possess genes encoding three decarboxylases (gadD1, gadD2, and gadD3) and two antiporters (gadT1 and gadT2). These are organized in two pairs (gadD1T1 and gadD2T2) and a distinct gadD3. While the creation of a gadD3 mutant has not been possible, analysis of 15 isogenic mutants has confirmed previous observations that GadD2/T2 are primarily responsible for surviving severe acid challenge (pH 2.8). However, we have now established that GadD1 plays a major role in growth at mildly acidic pHs (pH 5.1). When strain variation studies revealed that a large number of L. monocytogenes strains (including all serotype 4 strains) lack the gadD1 gadT1 pair, low-pH growth assays were carried out. It was found that the majority of strains that grew poorly at pH 5.1 lacked these genes. The strain-variable ability to grow in mildly acidic conditions may explain why non-serotype 4 strains of L. monocytogenes predominate in foods.

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