Project description:Peracetic acid (PAA), a strong oxidizing agent, has been widely used as a disinfectant in food processing settings as it does not produce harmful chlorinated by-products. In the present study, the transcriptional response of Listeria monocytogenes to 2.5 ppm of PAA was assessed using RNA-sequencing (RNA-seq). Our analysis revealed 12 differentially expressed genes, of which 9 were up-regulated (ohrR, ohrA, rpsN, lmo0637, lmo1973, fur, lmo2492, zurM, and lmo1007), and 3 were down-regulated (argG, lmo0604, lmo2156) in PAA treated samples compared to the control samples. A non-coding small RNA (rli32) was also found to be down-regulated. In detail, the organic peroxide toxicity protection (OhrA-OhrR) system, the metal homeostasis genes fur and zurM, the SbrE-regulated lmo0636-lmo0637 operon and a carbohydrate phosphotransferase system (PTS) operon component were induced under exposure of L. monocytogenes to PAA. Hence, this study identified key elements involved in the primary response of L. monocytogenes to oxidative stress caused by PAA. The investigation of the molecular mechanism of PAA response in L. monocytogenes is of utmost importance for the food industry, as this response can be induced in food-processing environments, as a result of inadequate rinsing during the disinfection process, that lead to PAA residues at low concentrations.
2024-10-04 | GSE269393 | GEO
Project description:Listeria monocytogenes from Hessian food and food processing environments
| PRJNA1414898 | ENA
Project description:Listeria monocytogenes from food and food processing environments in Germany
Project description:Listeria monocytogenes is a ubiquitous and psychrophilic foodborne pathogen commonly found in raw materials, ready to eat products and food environments. It was previously demonstrated that L. monocytogenes can grow faster at low temperature when unsaturated fatty acids (UFA) are present in its environment. In this study, we used comparative gene expression profiling of RNA-sequencing data to understand the impact of UFA on the behavior and cold adaptation of L. monocytogenes. We demonstrate that the incorporation of UFA into the membrane induces changes in the regulation of overall fatty acid biosynthesis, which prompts us to propose two hypotheses for UFA synthesis in L. monocytogenes. The general stress response is also highly impacted by the incorporation of UFA into the membrane at low temperature. In particular, we hypothesize that transcriptional regulation of cspB is not a temperature dependent mechanism, but could be related to a membrane fluidity stimulus. Furthermore, when UFA are incorporated into the membrane at low temperature, we observed overexpression of genes involved in flagella assembly. This study sheds light on the cold adaptation of L. monocytogenes in the presence of exogenous FA and on potential concerns for controlling these bacteria in food environments.
Project description:Listeria monocytogenes is an important food-borne pathogen that is responsible for contamination of a variety of food products. It causes listeriosis which is one of the most severe and serious diseases whose symptoms might include nausea and diarrhea. Also because of its ability to adhere to industrials’ surfaces, it is difficult for them to come up against this danger. Although there are researches in L. monocytogenes proteome, most of them are based on the study of a single strain, yet little is known about the proteome of more of the microbe’s strains. By studying the proteome of the microorganism with state-of-the-art mass spectrometry technology in terms of proteomics, we will be able to have an overall picture of the pathogenicity of the bacterium, as this is largely based on its ability to adapt to certain environments and to project its toxicity in them. To address that we provide a dataset of 2227 different proteins from 4 strains of L. monocytogenes, grouped by their molecular function and their biological process. The identified proteins confirm the complex molecular mechanisms of the bacterium.
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
2021-06-11 | GSE176617 | GEO
Project description:Listeria monocytogenes isolated from food samples
| PRJNA1166845 | ENA
Project description:Listeria monocytogenes sequencing under simulated food processing facility conditions.