scholarly journals Salt Stress Proteins Induced in Listeria monocytogenes

2002 ◽  
Vol 68 (4) ◽  
pp. 1491-1498 ◽  
Author(s):  
Ophélie Duché ◽  
Frédéric Trémoulet ◽  
Philippe Glaser ◽  
Jean Labadie
Keyword(s):  
Salt Stress ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Stress Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Food Preservation ◽  
Terminal Sequence ◽  
Phosphotransferase System ◽  
General Metabolism ◽  
Survival Mechanisms

ABSTRACT The ability of Listeria monocytogenes to tolerate salt stress is of particular importance, as this pathogen is often exposed to such environments during both food processing and food preservation. In order to understand the survival mechanisms of L. monocytogenes, an initial approach using two-dimensional polyacrylamide gel electrophoresis was performed to analyze the pattern of protein synthesis in response to salt stress. Of 400 to 500 visible proteins, the synthesis of 40 proteins (P < 0.05) was repressed or induced at a higher rate during salt stress. Some of the proteins were identified on the basis of mass spectrometry or N-terminal sequence analysis and database searching. Twelve proteins showing high induction after salt stress were similar to general stress proteins (Ctc and DnaK), transporters (GbuA and mannose-specific phosphotransferase system enzyme IIAB), and general metabolism proteins (alanine dehydrogenase, CcpA, CysK, EF-Tu, Gap, GuaB, PdhA, and PdhD).

scholarly journals Identification of Listeria monocytogenes Genes Involved in Salt and Alkaline-pH Tolerance

2003 ◽  
Vol 69 (6) ◽  
pp. 3137-3143 ◽  
Author(s):  
Rozenn Gardan ◽  
Pascale Cossart ◽  
Jean Labadie
Keyword(s):  
Salt Stress ◽  
Listeria Monocytogenes ◽  
Food Processing ◽  
Food Preservation ◽  
Alkaline Ph ◽  
Sequence Comparisons ◽  
Insertional Mutants ◽  
Ph Tolerance ◽  
Alkaline Tolerance ◽  
Intergenic Regions

ABSTRACT The capacity of Listeria monocytogenes to tolerate salt and alkaline stresses is of particular importance, as this pathogen is often exposed to such environments during food processing and food preservation. We screened a library of Tn917-lacZ insertional mutants in order to identify genes involved in salt and/or alkaline tolerance. We isolated six mutants sensitive to salt stress and 12 mutants sensitive to salt and alkaline stresses. The position of the insertion of the transposon was located in 15 of these mutants. In six mutants the transposon was inserted in intergenic regions, and in nine mutants it was inserted in genes. Most of the genes have unknown functions, but sequence comparisons indicated that they encode putative transporters.

scholarly journals Identification of Listeria monocytogenes Genes Contributing to Intracellular Replication by Expression Profiling and Mutant Screening

2006 ◽  
Vol 188 (2) ◽  
pp. 556-568 ◽  
Author(s):  
Biju Joseph ◽  
Karin Przybilla ◽  
Claudia Stühler ◽  
Kristina Schauer ◽  
Jörg Slaghuis ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Stress Proteins ◽  
Carbon Sources ◽  
Brain Heart Infusion ◽  
Nitrogen Sources ◽  
Pentose Phosphate ◽  
Intracellular Growth ◽  
Cell Infection ◽  
Phosphotransferase System ◽  
Isoleucine Leucine

ABSTRACT A successful transition of Listeria monocytogenes from the extracellular to the intracellular environment requires a precise adaptation response to conditions encountered in the host milieu. Although many key steps in the intracellular lifestyle of this gram-positive pathogen are well characterized, our knowledge about the factors required for cytosolic proliferation is still rather limited. We used DNA microarray and real-time reverse transcriptase PCR analyses to investigate the transcriptional profile of intracellular L. monocytogenes following epithelial cell infection. Approximately 19% of the genes were differentially expressed by at least 1.6-fold relative to their level of transcription when grown in brain heart infusion medium, including genes encoding transporter proteins essential for the uptake of carbon and nitrogen sources, factors involved in anabolic pathways, stress proteins, transcriptional regulators, and proteins of unknown function. To validate the biological relevance of the intracellular gene expression profile, a random mutant library of L. monocytogenes was constructed by insertion-duplication mutagenesis and screened for intracellular-growth-deficient strains. By interfacing the results of both approaches, we provide evidence that L. monocytogenes can use alternative carbon sources like phosphorylated glucose and glycerol and nitrogen sources like ethanolamine during replication in epithelial cells and that the pentose phosphate cycle, but not glycolysis, is the predominant pathway of sugar metabolism in the host environment. Additionally, we show that the synthesis of arginine, isoleucine, leucine, and valine, as well as a species-specific phosphoenolpyruvate-dependent phosphotransferase system, play a major role in the intracellular growth of L. monocytogenes.

Global Gene Expression of Listeria monocytogenes to Salt Stress

2012 ◽  
Vol 75 (5) ◽  
pp. 906-912 ◽  
Author(s):  
DONGRYEOUL BAE ◽  
CONNIE LIU ◽  
TING ZHANG ◽  
MARCUS JONES ◽  
SCOTT N. PETERSON ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salt Stress ◽  
Listeria Monocytogenes ◽  
Cell Growth ◽  
Expression Profiles ◽  
Brain Heart Infusion ◽  
Global Gene Expression ◽  
Phosphotransferase System ◽  
Transcript Levels ◽  
Qrt Pcr

Outbreaks of listeriosis caused by the ingestion of Listeria-contaminated ready-to-eat foods have been reported worldwide. Many ready-to-eat foods, such as deli meat products, contain high amounts of salt, which can disrupt the maintenance of osmotic balance within bacterial cells. To understand how Listeria monocytogenes adapts to salt stress, we examined the growth and global gene expression profiles of L. monocytogenes strain F2365 under salt stress using oligonucleotide probe-based DNA array and quantitative real-time PCR (qRT-PCR) analyses. The growth of L. monocytogenes in brain heart infusion (BHI) medium with various concentrations of NaCl (2.5, 5, and 10%) was significantly inhibited (P &lt; 0.01) when compared with growth in BHI with no NaCl supplementation. Microarray data indicated that growth in BHI medium with 1.2% NaCl upregulated 4 genes and down-regulated 24 genes in L. monocytogenes, which was confirmed by qRT-PCR. The transcript levels of genes involved in the uptake of glycine betaine/l-proline were increased, whereas genes associated with a putative phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS), metabolic enzymes, and virulence factor were down-regulated. Specifically, the expression levels of PTS transport genes were shown to be dependent on NaCl concentration. To further examine whether the down-regulation of PTS genes is related to decreased cell growth, the transcript levels of genes encoding components of enzyme II, involved in the uptake of various sugars used as the primary carbon source in bacteria, were also measured using qRT-PCR. Our results suggest that the decreased transcript levels of PTS genes may be caused by salt stress or reduced cell growth through salt stress. Here, we report global transcriptional profiles of L. monocytogenes in response to salt stress, contributing to an improved understanding of osmotolerance in this bacterium.

Isolation of Human Fibrinogen and its Derivatives by Affinity Chromatography on Gly-Pro-Arg-Pro-Lys-Fractogel

1990 ◽  
Vol 63 (03) ◽  
pp. 439-444 ◽  
Author(s):  
C Kuyas ◽  
A Haeberli ◽  
P Walder ◽  
P W Straub
Keyword(s):  
Gel Electrophoresis ◽  
Affinity Purification ◽  
Polyacrylamide Gel Electrophoresis ◽  
Ease Of Use ◽  
Terminal Sequence ◽  
Purification Method ◽  
Human Fibrinogen ◽  
Isolation Methods ◽  
One Step ◽  
Complementary Binding

SummaryWith an immobilized synthetic pentapeptide GlyProArgProLys comprising the N-terminal sequence GlyProArg of the α-chain of fibrin, a new affinity method for the quantitative isolation of fibrinogen out of anticoagulated plasma was developed. The method proved to be superior to all known isolation methods in respect to ease of use and yield, since fibrinogen could be isolated in one step out of plasma with a recovery of more than 95% when compared to the immunologically measurable amounts of fibrinogen. Moreover the amounts of contaminating proteins such as fibronectin, factor XIII or plasminogen were negligible and the purity of the isolated fibrinogen was higher than 95% as measured by polyacrylamide gel electrophoresis. The clottability was 90% and more. Another advantage of this affinity purification method is the possibility to isolate fibrinogen quantitatively out of small plasma samples (<5 ml). Further, abnormal fibrinogen molecules, provided their complementary binding site for GlyProArg is preserved, may also be quantitatively isolated independent of any solubility differences as compared to normal fibrinogen. In addition fibrin(ogcn) fragments originating from plasmic digestion can be separated on the basis of their affinity to GlyProArg. The described affinity gel can be used more than 50 times without any loss of capacity.

Biofilm Formation and Associated Genes in Listeria Monocytogenes

2017 ◽  
Vol 12 (3) ◽  
Author(s):  
S. R. Warke ◽  
V. C. Ingle ◽  
N. V. Kurkure ◽  
P. A. Tembhurne ◽  
Minakshi Prasad ◽  
...  
Keyword(s):  
Public Health ◽  
Listeria Monocytogenes ◽  
Multiplex Pcr ◽  
Food Processing ◽  
Biofilm Formation ◽  
Milk Samples ◽  
Biofilm Production ◽  
Food Borne ◽  
Serious Infections ◽  
Microtiter Assay

Listeria monocytogenes, an opportunistic food borne pathogen can cause serious infections in immunocompromised individuals. L. monocytogenes is capable of producing biofilm on the surface of food processing lines and instruments.The biofilm transfers contamination to food products and impose risk to public health. In the present study biofilm producing ability of L. monocytogenes isolates were investigated phenotypically and genotypically by microtiter assay and multiplex PCR, respectively. Out of 38 L. monocytogenes isolates 14 were recovered from animal clinical cases, 12 bovine environment and 12 from milk samples. A total of 3 (21.42%) clinical, 2 (16.66%) environment and 3 (25%) milk samples respectively, revealed biofilm production in microtiter assay. Cumulative results showed that 23 (60.52%) out of 38 strains of L. monocytogenes were positive for luxS and flaA gene and 1 (2.63%) was positive only for the flaA gene.

Listeria monocytogenes strains encoding premature stop codons in inlA invade mice and guinea pig fetuses in orally dosed dams

2013 ◽  
Vol 62 (12) ◽  
pp. 1799-1806 ◽  
Author(s):  
Anne Holch ◽  
Hanne Ingmer ◽  
Tine Rask Licht ◽  
Lone Gram
Keyword(s):  
Listeria Monocytogenes ◽  
Guinea Pig ◽  
Food Processing ◽  
Guinea Pigs ◽  
Stop Codon ◽  
Fetal Liver ◽  
Fatal Case ◽  
Premature Stop Codon ◽  
Tissue Samples ◽  
Pregnant Mice

Listeria monocytogenes is an important food-borne bacterial pathogen and listeriosis can result in abortions in pregnant women. The bacterium can colonize food-processing environments, where specific molecular subtypes can persist for years. The purpose of this study was to determine the virulence potential of a group of food-processing persistent L. monocytogenes strains encoding a premature stop codon in inlA (encoding internalin A) by using two orally dosed models, pregnant mice and pregnant guinea pigs. A food-processing persistent strain of L. monocytogenes invaded placentas (n = 58; 10 % positive) and fetuses (3 % positive) of pregnant mice (n = 9 animals per strain), similar to a genetically manipulated murinized strain, EGD-e InlA m* (n = 61; 3 and 2 %, respectively). In pregnant guinea pigs (n = 9 animals per bacterial strain), a maternofetal strain (from a human fetal clinical fatal case) was isolated from 34 % of placenta samples (n = 50), whereas both food-processing persistent strains were found in 5 % of placenta samples (n = 36 or 37). One of the food-processing persistent strains, N53-1, was found in up to 8 % of guinea pig fetal liver and brain samples, whereas the maternofetal control was found in 6 % of fetal tissue samples. As the food-processing persistent strains carry a premature stop codon in inlA but are invasive in orally dosed pregnant mice and guinea pigs, we hypothesize that listerial crossing of the placental barrier can occur by a mechanism that is independent of an interaction between E-cadherin and InlA.

scholarly journals Limited proteolysis of complement components C2 and factor B. Structural analogy and limited sequence homology

1979 ◽  
Vol 183 (3) ◽  
pp. 615-622 ◽  
Author(s):  
M A Kerr
Keyword(s):  
Sequence Homology ◽  
Polyacrylamide Gel Electrophoresis ◽  
Limited Proteolysis ◽  
Gel Filtration ◽  
Serine Proteinase ◽  
Terminal Sequence ◽  
Complement Components ◽  
Factor B ◽  
Terminal Residue ◽  
Covalently Linked

A method is described for the simultaneous purification of milligram quantities of complement components C2 and Factor B. Both products are homogeneous by the criteria of polyacrylamide-gel electrophoresis and N-terminal sequence analysis. Component C2 is cleaved by serine proteinase C1s at an X-Lys bond to give fragment C2a (approx. mol.wt. 74000) and fragment C2b (approx. mol.wt. 34000). The two fragments can be separated by gel filtration without the need for reducing or denaturing agents. Fragment C2b represents the N-terminal end of the molecule. Similar results were seen on cleavage of Factor B by Factor D in the presence of component C3. Again two non-covalently linked fragments are formed. The smaller, fragment Ba (approx. mol.wt. 36,000),) has threonine as the N-terminal residue, as does Factor B; the larger, fragment Bb (approx. mol. wt. 58000), has lysine as the N-terminal residue. A similar cleavage pattern is obtained on limited proteolysis of Factor B by trypsin, suggesting an Arg-Lys-or Lys-Lys bond at the point of cleavage. Although component C2 and Factor B show no apparent N-terminal sequence homology, a limited degree of sequence homology is seen around the sites of proteolytic cleavage.

Sign in / Sign up

Export Citation Format

Share Document