Listeria monocytogenes is a Gram-positive facultative intracellular bacterial pathogen that invades mammalian cells and escapes from membrane-bound vacuoles to replicate within the host cell cytosol. Gene products required for intracellular bacterial growth and bacterial spread to adjacent cells are regulated by a transcriptional activator known as PrfA. PrfA becomes activated following L. mono...

Analysis of Listeria monocytogenes ptsH, hprK, and ccpA mutants defective in carbon catabolite repression (CCR) control revealed significant alterations in the expression of PrfA-dependent genes. The hprK mutant showed high up-regulation of PrfA-dependent virulence genes upon growth in glucose-containing medium whereas expression of these genes was even slightly down-regulated in the ccpA mutan...

Novel mutations in prfA, the gene for the polypeptide release factor RF1 of Escherichia coli, were isolated using a positive genetic screen based on the parD (kis, kid) toxin-antitoxin system. This original approach allowed the direct selection of mutants with altered translational termination efficiency at UAG codons. The isolated prfA mutants displayed a approximately 10-fold decrease in UAG ...

The transcriptional activator PrfA, a member of the Crp/Fnr family, controls the expression of some key virulence factors necessary for infection by the human bacterial pathogen Listeria monocytogenes. Phenotypic screening identified ring-fused 2-pyridone molecules that at low micromolar concentrations attenuate L. monocytogenes cellular uptake by reducing the expression of virulence genes. The...

To determine serial changes in hepatocellular carcinomas (HCCs) treated with percutaneous radiofrequency ablation (PRFA) at long-term serial follow-up biphasic helical computed tomography (CT). Thirty five HCCs (range, 2.1 – 7.0 cm in diameter; mean ± SD, 3.0 ± 1.5 cm) in 27 patients (mean age, 67.2 years) were enrolled in our study. Every patient will received biphasic spiral CT study before a...

The genus Listeria includes (i) the opportunistic pathogens L. monocytogenes and L. ivanovii, (ii) the saprotrophs L. innocua, L. marthii, and L. welshimeri, and (iii) L. seeligeri, an apparent saprotroph that nevertheless typically contains the prfA virulence gene cluster. A novel 10-loci multilocus sequence typing scheme was developed and used to characterize 67 isolates representing six List...

OBJECTIVES The aim of this study was to compare the clinical effectiveness and cost of percutaneous radiofrequency ablation (PRFA) and surgical resection (SRS) for the management of early stage Hepatocellular Carcinoma. METHODS A systematic literature search of articles in English, French, and Chinese was performed using online databases. Only articles with patients classified as Child-Pugh C...

Most human listeriosis outbreaks are caused by Listeria monocytogenes evolutionary lineage I strains which possess four exotoxins: a phosphatidylinositol-specific phospholipase C (PlcA), a broad-range phospholipase C (PlcB), listeriolysin O (LLO) and listeriolysin S (LLS). The simultaneous contribution of these molecules to virulence has never been explored. Here, the importance of these four e...

AIM Recently percutaneous ethanol injection (PEI) turned into percutaneous radiofrequency ablation (PRFA), and it has become widely used for the treatment of hepatocellular carcinoma (HCC). The present study was to compare the incidence in postoperative HCC recurrence between these two therapeutic approaches. METHODS One hundred and sixty-eight first-time HCC in patient cases were chosen for ...

Reporter gene fusions were used to investigate the contributions of PrfA DNA binding sites to Listeria monocytogenes virulence gene expression. Our results suggest that the DNA sequence of PrfA binding sites determines the levels of expression of certain virulence genes, such as hly and mpl. Other virulence genes, such as actA and plcB, may depend upon additional factors for full regulation of ...