Project description:Survival of the foodborne pathogen Listeria monocytogenes in acidic environments (e.g., stomach and low pH foods) is vital to its transmission. L. monocytogenes grows at temperatures as low as 2°C, and refrigerated, ready-to-eat foods have been sources of L. monocytogenes outbreaks. The purpose of this study was to determine whether growth at a low temperature (i.e., 7°C) affects the response of L. monocytogenes to sudden acid shock.
2011-07-01 | GSE22672 | GEO
Project description:Listeria mopnocytogenes from imported foods
Project description:Phosphopeptides were identified in Listeria monocytogesn strain constitutivally expressing PrfA. Also, the phosphoproteins and proteins were identified that are overexpressed/underextressed in response to PrfA.
Project description:Listeria monocytogenes is the ubiquitous food-borne pathogen which causes listeriosis, a disease with a high mortality rate, mostly transmitted through contaminated ready-to-eat foods (EFSA, 2018). To better understand the systemic response of such microorganism exposed at three environmental factors (T, pH and NaCl), the proteome of a L. monocytogenes strain, which was isolated from a meat product (Coppa di testa) linked to a listeriosis outbreak occurred in Marche region (Italy) in 2016, was investigated in order to identify differences in its protein patterns.
Project description:ISG15 is primarily documented as an interferon-stimulated, ubiquitin-like protein (ubl), which has anti-viral activity. Although ISG15 was the founding member of the ubl protein family, very little is known about its function. We have found that ISG15 expression in non-phagocytic cells is dramatically induced upon Listeria infection and that surprisingly this induction can be Type I Interferon independent. Listeria-mediated ISG15 induction depends on the cytosolic surveillance pathway, which senses bacterial DNA and signals through STING, TBK1, IRF3 and IRF7. Most importantly, we observed that ISG15 expression restricts Listeria infection both in vitro and in vivo. We then made use of Stable Isotope Labeling in tissue culture (SILAC) to identify the ISGylated proteins that could be responsible for the ISG15-mediated protective effect. Our SILAC analysis revealed that overexpression of ISG15 leads to a striking ISGylation of integral membrane proteins of the endoplasmic reticulum and Golgi apparatus, which correlates with increased canonical secretion of cytokines. Taken together, our data reveal a previously uncharacterized signaling pathway that restricts Listeria infection and acts via ISGylation, reinforcing the view that ISG15 is a key component of the innate immune arsenal of the mammalian host.
Project description:ISG15 is primarily documented as an interferon-stimulated, ubiquitin-like protein (ubl), which has anti-viral activity. Although ISG15 was the founding member of the ubl protein family, very little is known about its function. We have found that ISG15 expression in non-phagocytic cells is dramatically induced upon Listeria infection and that surprisingly this induction can be Type I Interferon independent. Listeria-mediated ISG15 induction depends on the cytosolic surveillance pathway, which senses bacterial DNA and signals through STING, TBK1, IRF3 and IRF7. Most importantly, we observed that ISG15 expression restricts Listeria infection both in vitro and in vivo. We then made use of Stable Isotope Labeling in tissue culture (SILAC) to identify the ISGylated proteins that could be responsible for the ISG15-mediated protective effect. Our SILAC analysis revealed that overexpression of ISG15 leads to a striking ISGylation of integral membrane proteins of the endoplasmic reticulum and Golgi apparatus, which correlates with increased canonical secretion of cytokines. Taken together, our data reveal a previously uncharacterized signaling pathway that restricts Listeria infection and acts via ISGylation, reinforcing the view that ISG15 is a key component of the innate immune arsenal of the mammalian host.
Project description:The foodborne pathogen Listeria monocytogenes uses a number of transcriptional regulators, including the negative regulator HrcA, to control gene expression under different environmental conditions and in response to stress. Gene expression patterns of DhrcA stationary phase cells were compared to wt to identify hrcA-dependent genes. We identified 61 HrcA-dependent genes that showed significant expression ratios (adj. P < 0.05), with ≥ 1.5-fold differential expression between ΔhrcA and wt. Combined with microarray analysis, Hidden Markov Model searches show HrcA directly repress at least 8 genes. Keywords: Listeria monocytogenes, HrcA regulon, stationary phase
Project description:The foodborne pathogen Listeria monocytogenes uses a number of transcriptional regulators, including the negative regulator CtsR, to control gene expression under different environmental conditions and in response to stress. Gene expression patterns of DctsR log phase cells were compared to both wt and ictsR-mcsA log phase cells grown with 0.5mM IPTG to identify CtsR-dependent genes.We identified 62 CtsR-dependent genes that showed significant expression ratios (adj. P < 0.05), with ≥ 1.5-fold differential expression either between ΔctsR and wt or between ΔctsR and ictsR-mcsA. Keywords: Listeria monocytogenes, CtsR regulon, log phase
Project description:Listeria monocytogenes strain 10403S has been studied extensively for stress response activity toward multiple stressors (acid, osmotic, cold, high temperature, etc.) as well as multiple stress regulons (SigB, CtsR, HrcA, etc.). Here we aimed to determine the transcriptional response of Listeria monocytogenes in early log phase towards the strong oxidative stress imposed by ClO2. The elucidation of such a response allows for further a more completel understanding of the mechanism of inactivation by sanitizers, specifically ClO2.