scholarly journals Detection of premature stop codons leading to truncated internalin A among food and clinical strains of Listeria monocytogenes

2017 ◽  
Vol 63 ◽  
pp. 6-11 ◽  
Author(s):  
Margarida Ferreira da Silva ◽  
Vânia Ferreira ◽  
Rui Magalhães ◽  
Gonçalo Almeida ◽  
Artur Alves ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Clinical Strains ◽  
Stop Codons ◽  
Internalin A

scholarly journals Whole-Genome Sequences of Six Listeria monocytogenes Strains Isolated from Food

2018 ◽  
Vol 7 (14) ◽  
Author(s):  
Jule Anna Horlbog ◽  
Hyein Jang ◽  
Gopal Gopinath ◽  
Roger Stephan ◽  
Claudia Guldimann
Keyword(s):  
Listeria Monocytogenes ◽  
Amino Acid ◽  
Whole Genome ◽  
Genome Sequences ◽  
Content Type ◽  
Milk Products ◽  
Stop Codons

Here, we report the whole-genome sequences of six Listeria monocytogenes strains isolated from meat and milk products in Switzerland. All of these strains carry premature stop codons or amino acid deletions in inlA.

scholarly journals Expression of Internalin a and Biofilm Formation among Listeria Monocytogenes Clinical Isolates

2009 ◽  
Vol 22 (1) ◽  
pp. 183-193 ◽  
Author(s):  
G. Franciosa ◽  
A. Maugliani ◽  
C. Scalfaro ◽  
F. Floridi ◽  
P. Aureli
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Clinical Isolates ◽  
Internalin A

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 Whole-Genome Sequences of 12 Clinical Strains of Listeria monocytogenes

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Guojie Cao ◽  
Jianmin Zhang ◽  
Xuebin Xu ◽  
Huiming Jin ◽  
Xiaowei Yang ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Whole Genome ◽  
Genome Sequences ◽  
Clinical Strains

scholarly journals Variable Adhesion of Listeria monocytogenes Isolates from Food-Processing Facilities and Clinical Cases to Inert Surfaces

2007 ◽  
Vol 70 (7) ◽  
pp. 1569-1578 ◽  
Author(s):  
ODILE TRESSE ◽  
KELLY SHANNON ◽  
ANTHONY PINON ◽  
PIERRE MALLE ◽  
MICHÈLE VIALETTE ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Microtiter Plate ◽  
Clinical Strains ◽  
Microtiter Plates ◽  
Industrial Strains ◽  
Cheese Industry ◽  
Adhesion Rate ◽  
Inert Surfaces

One hundred one strains of Listeria monocytogenes isolated from seafood and cheese industry samples and from patients with listeriosis were assessed using a microtiter plate method for adhesion to polystyrene and stainless steel surfaces. The adhesion rate for these strains ranged from 3.10 to 35.29% with an inoculum of 8 × 108 cells per well. A strong correlation was found between adhesion to polystyrene and stainless steel microtiter plates, indicating that the intrinsic ability of L. monocytogenes to adhere to inert surfaces is stronger than the influence of the surface's physicochemical properties. The clinical strains were less adherent to inert surfaces than were the industrial strains. By integrating other factors such as location of the industrial strains, contamination type of the clinical strains, serotype, and pulsotype into the analysis, some weak but significant differences were noted. For the industrial isolates, the number of cells attached to both surfaces differed significantly depending on whether they were isolated from food or food-processing environments in the seafood and cheese industry. For clinical isolates, sporadic strains exhibited greater adhesion to polystyrene than did epidemic strains. Strains belonging to the pulsed-field gel electrophoretype clusters A and M (lineages II and I, respectively) were less able to adhere to polystyrene and stainless steel than were strains in the more common clusters.

scholarly journals Expression of Truncated Internalin A Is Involved in Impaired Internalization of Some Listeria monocytogenes Isolates Carried Asymptomatically by Humans

2003 ◽  
Vol 71 (3) ◽  
pp. 1217-1224 ◽  
Author(s):  
Maïwenn Olier ◽  
Fabrice Pierre ◽  
Sandrine Rousseaux ◽  
Jean-Paul Lemaître ◽  
André Rousset ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Surface Protein ◽  
Human Infection ◽  
Host Cells ◽  
Genetic Lineage ◽  
Chick Embryos ◽  
Asymptomatic Carriage ◽  
High Degree ◽  
Internalin A

ABSTRACT Fourteen human carriage Listeria monocytogenes isolates were compared to sporadic and epidemic-associated human strains in order to ascertain the pathogenic behavior of these unrecognized asymptomatic strains. Experimental infection of 14-day-old chick embryos revealed that the majority of the carriage strains were attenuated for virulence. Of the 10 attenuated carriage strains, 5 were affected in their invasion capacities in vitro. Western blot analysis with antibody directed against InlA, the surface protein implicated in the internalization in host cells, allowed correlation between the ability of the carriage strains to enter Caco-2 cells and InlA expression. Indeed, these five carriage strains produced truncated forms of InlA. Four of the five truncated forms of InlA had an apparent molecular mass of 47 kDa. In order to assess the existence of a genetic lineage, partial sequences of inlA gene of these four strains were compared and revealed that they had a high degree of sequence conservation at the gene (99.86%) and amino acid (100%) levels. Comparison of their nucleotide sequences with that of the corresponding segment of inlA from EGD-e and Scott A strains, taken as epidemic references, showed more divergence. Taken together, these observations suggest the presence of specific traits that characterize L. monocytogenes strains isolated during asymptomatic carriage. Some of these traits could provide some explanations about the determinants that make them unable to cause systemic human infection.

scholarly journals Select Listeria monocytogenes Subtypes Commonly Found in Foods Carry Distinct Nonsense Mutations in inlA, Leading to Expression of Truncated and Secreted Internalin A, and Are Associated with a Reduced Invasion Phenotype for Human Intestinal Epithelial Cells

2005 ◽  
Vol 71 (12) ◽  
pp. 8764-8772 ◽  
Author(s):  
K. K. Nightingale ◽  
K. Windham ◽  
K. E. Martin ◽  
M. Yeung ◽  
M. Wiedmann
Keyword(s):  
Listeria Monocytogenes ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Surface Protein ◽  
The United States ◽  
Intestinal Epithelial ◽  
Source Information ◽  
Human Intestinal Epithelial Cells ◽  
Internalin A ◽  
Mutation Type

ABSTRACT The surface protein internalin A (InlA) contributes to the invasion of human intestinal epithelial cells by Listeria monocytogenes. Screening of L. monocytogenes strains isolated from human clinical cases (n = 46), foods (n = 118), and healthy animals (n = 58) in the United States revealed mutations in inlA leading to premature stop codons (PMSCs) in L. monocytogenes ribotypes DUP-1052A and DUP-16635A (PMSC mutation type 1), DUP-1025A and DUP-1031A (PMSC mutation type 2), and DUP-1046B and DUP-1062A (PMSC mutation type 3). While all DUP-1046B, DUP-1062A, DUP-16635A, and DUP-1031A isolates (n = 76) contained inlA PMSCs, ribotypes DUP-1052A and DUP-1025A (n = 72) contained isolates with and without inlA PMSCs. Western immunoblotting showed that all three inlA PMSCs result in the production of truncated and secreted InlA. Searches of the Pathogen Tracker database, which contains subtype and source information for more than 5,000 L. monocytogenes isolates, revealed that the six ribotypes shown to contain isolates with inlA PMSCs were overall more commonly isolated from foods than from human listeriosis cases. L. monocytogenes strains carrying inlA PMSCs also showed significantly (P = 0.0004) reduced invasion of Caco-2 cells compared to isolates with homologous 3′ inlA sequences without PMSCs. Invasion assays with an isogenic PMSC mutant further supported the observation that inlA PMSCs lead to reduced invasion of Caco-2 cells. Our data show that specific L. monocytogenes subtypes which are common among U.S. food isolates but rare among human listeriosis isolates carry inlA mutations that are associated with, and possibly at least partially responsible for, an attenuated invasion phenotype.

scholarly journals Lactococcus lactis STRAINS ECTOPICALLY EXPRESS THE INTERNALIN-A PROTEIN FROM Listeria monocytogenes UNDER THE BACTERIAL SEPTUM REGION

2006 ◽  
Vol 28 (63) ◽  
Author(s):  
Jane E. Gabriel ◽  
Vasco A. C. Azevedo ◽  
Philippe Langella
Keyword(s):  
Listeria Monocytogenes ◽  
Cell Surface ◽  
Lactococcus Lactis ◽  
Expression Pattern ◽  
Present Report ◽  
Spatial Expression ◽  
Spatial Expression Pattern ◽  
Exogenous Genes ◽  
Lactic Bacteria ◽  
Internalin A

In the present report, we describe how Lactococcus lactis strains ectopically express the internalin-A protein from Listeria monocytogenes at the cell surface, situated specifically under the bacterial septum region. Such findings provide relevant insights into the spatial expression pattern of exogenous genes in lactic bacteria.

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