Project description:A previously described low-fitness, high stress-resistant, variant of Listeria monocytogenes LO28 WT was subjected to an experimental evolution regime, selecting (in two parallel lines) for increased fitness in unstressed conditions. Evolved variants with increased fitness reverted to WT-like stress resistance. Whole genome sequencing and proteomics were used to identify differences between the ancestral and evolved strains.
Project description:Persistence of Listeria monocytogenes in retail deli environments is a serious food safety issue, potentially leading to cross-contamination of ready-to-eat foods such as deli meats, salads, and cheeses. We previously discovered strong evidence of L. monocytogenes persistence in delis across multiple states. We hypothesized that this was correlated with isolates’ innate characteristics, such as biofilm-forming capacity or gene differences.We further chose four isolates for RNA-sequencing analysis and compared their global biofilm transcriptome to their global planktonic transcriptome. Analysis of biofilm vs planktonic gene expression did not show the expected differences in gene expression patterns. Overall, L. monocytogenes persistence in the deli environment is likely a matter of poor sanitation and/or facility design, rather than isolates’ biofilm-forming capacity, sanitizer tolerance, or genomic content
Project description:Investigation of whole genome gene expression level changes in Listeria monocytogenes EGD-e during incubation (0, 15 min, 30 min) in two types of soil extracts (TA, DA).
Project description:Despite high vaccination coverage, pertussis is on the rise in many countries including Czech Republic. To better understand B. pertussis resurgence we compared the changes in genome structures between Czech vaccine and circulating strains and subsequently, we determined how these changes translated into global transcriptomic and proteomic profiles. The whole-genome sequencing revealed that both historical and recent isolates of B. pertussis display substantial variation in genome organization and cluster separately. The RNA-seq and LC-MS/MS analyses indicate that these variations translated into discretely separated transcriptomic and proteomic profiles. Compared to vaccine strains, recent isolates displayed increased expression of flagellar genes and decreased expression of polysaccharide capsule operon. Czech strains (Bp46, K10, Bp155, Bp318 and Bp6242)exhibited increased expression of T3SS and sulphate metabolism genes when compared to Tohama I. In spite of 50 years of vaccination the Czech vaccine strains (VS67, VS393 and VS401) differ from recent isolates to a lesser extent than from another vaccine strain Tohama I.
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.
