scholarly journals Construction of deletion mutants in the phosphotransferase transport system and adenosine triphosphate-binding cassette transporters in Listeria monocytogenes and analysis of their growth under different stress conditions

2013 ◽  
Vol 2 (3) ◽  
pp. 38
Author(s):  
Marina Ceruso ◽  
Pina Fratamico ◽  
Claudia Chirollo ◽  
Rosanna Taglialatela ◽  
Maria Luisa Cortesi ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Adenosine Triphosphate ◽  
Transport System ◽  
Stress Conditions ◽  
Deletion Mutants ◽  
Phosphotransferase Transport System

scholarly journals Gbu Glycine Betaine Porter and Carnitine Uptake in Osmotically Stressed Listeria monocytogenes Cells

2002 ◽  
Vol 68 (11) ◽  
pp. 5647-5655 ◽  
Author(s):  
Mary Lou Mendum ◽  
Linda Tombras Smith
Keyword(s):  
Listeria Monocytogenes ◽  
Transport System ◽  
Glycine Betaine ◽  
Compatible Solutes ◽  
High Salt ◽  
Uptake System ◽  
Food Borne ◽  
Protein Mutants ◽  
Carnitine Uptake ◽  
Do So

ABSTRACT The food-borne pathogen Listeria monocytogenes grows actively under high-salt conditions by accumulating compatible solutes such as glycine betaine and carnitine from the medium. We report here that the dominant transport system for glycine betaine uptake, the Gbu porter, may act as a secondary uptake system for carnitine, with a Km of 4 mM for carnitine uptake and measurable uptake at carnitine concentrations as low as 10 μM. This porter has a Km for glycine betaine uptake of about 6 μM. The dedicated carnitine porter, OpuC, has a Km for carnitine uptake of 1 to 3 μM and a V max of approximately 15 nmol/min/mg of protein. Mutants lacking either opuC or gbu were used to study the effects of four carnitine analogs on growth and uptake of osmolytes. In strain DP-L1044, which had OpuC and the two glycine betaine porters Gbu and BetL, triethylglycine was most effective in inhibiting growth in the presence of glycine betaine, but trigonelline was best at inhibiting growth in the presence of carnitine. Carnitine uptake through OpuC was inhibited by γ-butyrobetaine. Dimethylglycine inhibited both glycine betaine and carnitine uptake through the Gbu porter. Carnitine uptake through the Gbu porter was inhibited by triethylglycine. Glycine betaine uptake through the BetL porter was strongly inhibited by trigonelline and triethylglycine. These results suggest that it is possible to reduce the growth of L. monocytogenes under osmotically stressful conditions by inhibiting glycine betaine and carnitine uptake but that to do so, multiple uptake systems must be affected.

scholarly journals Mild Stress Conditions during Laboratory Culture Promote the Proliferation of Mutations That Negatively Affect Sigma B Activity in Listeria monocytogenes

2020 ◽  
Vol 202 (9) ◽  
Author(s):  
Duarte N. Guerreiro ◽  
Jialun Wu ◽  
Charlotte Dessaux ◽  
Ana H. Oliveira ◽  
Teresa Tiensuu ◽  
...  
Keyword(s):  
Heat Stress ◽  
Listeria Monocytogenes ◽  
Laboratory Culture ◽  
Stress Conditions ◽  
Mild Stress ◽  
Whole Genome ◽  
Content Type ◽  
Acid Sensitivity ◽  
Stop Codons ◽  
Mild Heat

ABSTRACT In Listeria monocytogenes, the full details of how stress signals are integrated into the σB regulatory pathway are not yet available. To help shed light on this question, we investigated a collection of transposon mutants that were predicted to have compromised activity of the alternative sigma factor B (σB). These mutants were tested for acid tolerance, a trait that is known to be under σB regulation, and they were found to display increased acid sensitivity, similar to a mutant lacking σB (ΔsigB). The transposon insertions were confirmed by whole-genome sequencing, but in each case, the strains were also found to carry a frameshift mutation in the sigB operon. The changes were predicted to result in premature stop codons, with negative consequences for σB activation, independently of the transposon location. Reduced σB activation in these mutants was confirmed. Growth measurements under conditions similar to those used during the construction of the transposon library revealed that the frameshifted sigB operon alleles conferred a growth advantage at higher temperatures, during late exponential phase. Mixed-culture experiments at 42°C demonstrated that the loss of σB activity allowed mutants to take over a population of parental bacteria. Together, our results suggest that mutations affecting σB activity can arise during laboratory culture because of the growth advantage conferred by these mutations under mild stress conditions. The data highlight the significant cost of stress protection in this foodborne pathogen and emphasize the need for whole-genome sequence analysis of newly constructed strains to confirm the expected genotype. IMPORTANCE In the present study, we investigated a collection of Listeria monocytogenes strains that all carried sigB operon mutations. The mutants all had reduced σB activity and were found to have a growth advantage under conditions of mild heat stress (42°C). In mixed cultures, these mutants outcompeted the wild type when mild heat stress was present but not at an optimal growth temperature. An analysis of 22,340 published L. monocytogenes genome sequences found a high rate of premature stop codons present in genes positively regulating σB activity. Together, these findings suggest that the occurrence of mutations that attenuate σB activity can be favored under conditions of mild stress, probably highlighting the burden on cellular resources that stems from deploying the general stress response.

scholarly journals Biofilm Formation among Clinical and Food Isolates ofListeria monocytogenes

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Joana Barbosa ◽  
Sandra Borges ◽  
Ruth Camilo ◽  
Rui Magalhães ◽  
Vânia Ferreira ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Listeria Monocytogenes ◽  
Osmotic Stress ◽  
Environmental Conditions ◽  
Biofilm Formation ◽  
Stress Conditions ◽  
Acidic Stress ◽  
Biofilm Production ◽  
Oflisteria Monocytogenes ◽  
Clinical Cases

Objective. A total of 725Listeria monocytogenesisolates, 607 from various foods and 118 from clinical cases of listeriosis, were investigated concerning their ability to form biofilms, at 4°C during 5 days and at 37°C during 24 h.Methods. Biofilm production was carried out on polystyrene tissue culture plates. FiveL. monocytogenesisolates were tested for biofilm formation after being exposed to acidic and osmotic stress conditions.Results. Significant differences (P<0.01) between clinical and food isolates were observed. At 37°C for 24 h, most food isolates were classified as weak or moderate biofilm formers whereas all the clinical isolates were biofilm producers, although the majority were weak. At 4°C during 5 days, 65 and 59% isolates, from food and clinical cases, respectively, were classified as weak. After both sublethal stresses, at 37°C just one of the five isolates tested was shown to be more sensitive to subsequent acidic exposure. However, at 4°C both stresses did not confer either sensitivity or resistance.Conclusions. Significant differences between isolates origin, temperature, and sublethal acidic stress were observed concerning the ability to form biofilms. Strain, origin, and environmental conditions can determine the level of biofilm production byL. monocytogenesisolates.

scholarly journals The ABC Transporter AnrAB Contributes to the Innate Resistance of Listeria monocytogenes to Nisin, Bacitracin, and Various β-Lactam Antibiotics

2010 ◽  
Vol 54 (10) ◽  
pp. 4416-4423 ◽  
Author(s):  
Barry Collins ◽  
Nicola Curtis ◽  
Paul D. Cotter ◽  
Colin Hill ◽  
R. Paul Ross
Keyword(s):  
Multidrug Resistance ◽  
Listeria Monocytogenes ◽  
Abc Transporter ◽  
Deletion Mutants ◽  
Gene Encoding ◽  
Innate Resistance ◽  
Enhanced Sensitivity ◽  
The Creation ◽  
Multidrug Resistance Transporter ◽  
Selection Of

ABSTRACT A mariner transposon bank was used to identify loci that contribute to the innate resistance of Listeria monocytogenes to the lantibiotic nisin. In addition to highlighting the importance of a number of loci previously associated with nisin resistance (mprF, virRS, and telA), a nisin-sensitive phenotype was associated with the disruption of anrB (lmo2115), a gene encoding the permease component of an ABC transporter. The contribution of anrB to nisin resistance was confirmed by the creation of nonpolar deletion mutants. The loss of this putative multidrug resistance transporter also greatly enhanced sensitivity to bacitracin, gallidermin, and a selection of β-lactam antibiotics. A comparison of the relative antimicrobial sensitivities of a number of mutants established the ΔanrB strain as being one of the most bacitracin-sensitive L. monocytogenes strains identified to date.

scholarly journals A di- and tripeptide transport system can supply Listeria monocytogenes Scott A with amino acids essential for growth.

1995 ◽  
Vol 61 (1) ◽  
pp. 226-233 ◽  
Author(s):  
A Verheul ◽  
A Hagting ◽  
M R Amezaga ◽  
I R Booth ◽  
F M Rombouts ◽  
...  
Keyword(s):  
Amino Acids ◽  
Listeria Monocytogenes ◽  
Transport System
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