ABSTRACT: Bligh and Dyer lipid extraction of Listeria monocytogenes cells previously stressed by the cultivation with nisin and CLPs in sublethal concentrations.
Project description:Bligh and Dyer lipid extraction of Listeria monocytogenes cells previously stressed by the cultivation with nisin and CLPs in sublethal concentrations.
Project description:Untargeted Proteomics of full protein extract of Listeria monocytogenes cultures with sublethal concentrations of nisin and fengycin.
Project description:The human pathogenic bacterium Listeria monocytogenes was exposed to antibiotics both during clinical treatment and as a saprophyte. As one of the keys to successful treatment is continued antibiotic sensitivity, the purpose of this study was to determine if exposure to sublethal antibiotic concentrations would affect the bacterial physiology and potentially induce tolerance to antibiotics. Transcriptomic analyses demonstrated that each of four antibiotics caused a compound-specific gene expression pattern related to (the) mode-of-action of the particular antibiotic. All four antibiotics caused the same changes in expression of several metabolic genes indicating a shift from aerobic to anaerobic metabolism driven by the induction of lmo1634 and the repression of alsA and lmo1992. This shift in metabolism could be a survival strategy in response to antibiotics and is further supported by the observation that a Îlmo1634 mutant was more sensitive to bactericidal antibiotics. The monocin locus encoding a cryptic prophage was induced by co-trimoxazole and repressed by ampicillin and gentamicin. This expression pattern correlated with the observed antibiotic-dependent biofilm formation, indicating a role of monocin in antibiotic-induced biofilm formation and a ÎlmaDCBA mutant confirmed this correlation. Thus, sublethal concentrations of antibiotics caused metabolic and physiological changes indicating that the organism is preparing to withstand lethal concentrations of antibiotics. Investigation of mRNA and sRNA expression profiles of L. monocytogenes EGD cells exposed to sublethal concentrations of four different antibiotics i.e. ampicillin, tetracycline, gentamicin and co-trimoxazole for 3h.
Project description:Investigation of whole genome gene expression level changes in Listeria monocytogenes LO28 delta-lhrC1-5 mutant, compared to the wild type strain. The lhrC1-5 genes encode the regulatory sRNAs LhrC1-5. The microarray studied the gene expression of unstressed cells and cells exposed to cefuroxime for 30 min. The lhrC1-5 mutant employed in this study is further described in Sievers et al. (2014) A multicopy sRNA of Listeria monocytogenes regulates expression of the virulence adhesin LapB. Nucleic Acids Res. 42:9383-98. A twelve chip study using RNA extracted from 6 different cultures of L. monocytogenes LO28 delta-lhrC1-5 (three unstressed and three stressed cultures) and 6 different cultures of L. monocytognes LO28 wild-type (three unstressed cultures and three stressed cultures).
Project description:In present work, we established a simple and robust protocol for universal bacterial phosphoproteomic analysis underlying the rationale of methanol-based LLE protein extraction and cleanup. Using the SDS lysis as the conventional protocol control, we carefully evaluated the efficiency of protein extraction and contaminants removal in terms of phosphopeptide enrichment, phosphopeptide identification and quantification in Listeria monocytogenes, a gram-positive bacterium. We found out the addition of urea, a chaotropic agent, facilitating the protein denaturation and then the protein-impurity dissociation, largely enhanced the protein extraction and sample purity. We further demonstrated the feasibility of this unified LLE platform for studying both gram-positive and gram-negative phosphoproteomes.
Project description:A wild type strain of Listeria monocytogenes (L. mono) was used for infections. Mice were infected subcutaneously on the footpad with a sublethal dose of 1 × 106 colony-forming units (CFU). Mice were left for 2 days before being sacrificed. Control cells were from either PBS injected mouse or from the uninjected leg of infected animal.
Project description:A wild type strain of Listeria monocytogenes (L. mono) was used for infections. Mice were infected subcutaneously on the footpad with a sublethal dose of 1 × 10^6 colony-forming units (CFU). Mice were left for indicated times before being sacrificed. Control cells were from either PBS injected mouse or from the uninjected leg of infected animal.
Project description:Untargeted proteomics was carried out to study the Listeria monocytogenes responses to free and nano-encapsulated lantibiotic nisin.
Project description:Murine dendritic cells were derived from bone-marrow of 4 mice using GM-CSF. The DC were treated with RNA from gram-positive bacteria Listeria monocytogenes packaged in DOTAP or TLR7 agonist R848. Negative controls were DOTAP with no RNA or mock.