Disease relevance of plcB

• Listeria monocytogenes Mutants Carrying Newcastle Disease Virus F Gene Fused to its actA and plcB: In vitro Expression and Immunogenicity in Chickens [1].
• In the present study, we characterized the mechanisms of enhanced E-selectin expression using L. monocytogenes wild type (EGD), the isogenic in-frame deletion mutants for phosphatidylcholine (PC)- and phosphatidylinositol (PI)-specific phospholipases EGD delta plcA and EGD delta plcB, as well as the nonvirulent control strain Listeria innocua [2].
• The lecithinase gene of the intracellular pathogen Listeria monocytogenes, plcB, was identified in a 5,648-bp DNA fragment which expressed lecithinase activity when cloned into Escherichia coli [3].
• Phospholipase C plays a key role in the pathogenesis of several bacterial infections, for example, those caused by Clostridium perfringens and Listeria monocytogenes [4].

High impact information on plcB

• Infection of endothelial cells with EGD delta plcA or EGD delta plcB for 6 h induced, as compared with EGD wild type, intermediate levels of E-selectin mRNA and protein as well as PMN rolling and adhesion at a shear rate of 1 dyne/cm2, indicating that both bacterial phospholipases are required for a maximal effect [2].
• Escape from these vacuoles is mediated in part by a bacterial phospholipase C (PC-PLC), whose activation requires cleavage of an N-terminal peptide [5].
• A mutant of Listeria monocytogenes EGD was constructed that carries an extended deletion removing the entire PrfA-regulated gene cluster from plcA to plcB and a second deletion inactivating the inlA gene [6].
• Compartmentalization of the Broad-Range Phospholipase C Activity to the Spreading Vacuole Is Critical for Listeria monocytogenes Virulence [7].
• Membrane fusion induced by the catalytic activity of a phospholipase C/sphingomyelinase from Listeria monocytogenes [8].

Chemical compound and disease context of plcB

• Subcytolytic concentrations of phospholipase C can perturb host cells by activating the arachidonic acid cascade or protein kinase C. Nonlethal phospholipases C, such as the Listeria monocytogenes PLC-A, appear to enhance the release of the organism from the host cell phagosome [9].

Biological context of plcB

• Given the pathogenic potential of L. monocytogenes, we created an attenuated mutant strain bearing double deletions in the actA and plcB virulence genes for an initial clinical safety study of a prototype L. monocytogenes vector in adults [10].
• We assessed the effect of carbohydrates on virulence gene expression in a panel of wild-type isolates of L. monocytogenes by using the PrfA-dependent phospholipase C gene plcB as a reporter [11].
• Diheptanoylphosphatidyl-2-O-methylinositol is a good inhibitor of PI-specific phospholipase C because it blocks the initial phosphotransferase step in PI hydrolysis [12].
• Listeria monocytogenes phospholipase C-dependent calcium signaling modulates bacterial entry into J774 macrophage-like cells [13].
• DNA sequences of M. kansasii and M. marinum homologous to the genes encoding phospholipase C from M. tuberculosis and M. ulcerans were identified by DNA-DNA hybridization and sequencing [4].

Anatomical context of plcB

• The ActA protein of Listeria monocytogenes is an essential virulence factor and is required for intracellular bacterial motility and cell-to-cell spread. plcB, cotranscribed with actA, encodes a broad-specificity phospholipase C that contributes to lysis of host cell vacuoles and cell-to-cell spread [14].
• The broad-range phospholipase C and a metalloprotease mediate listeriolysin O-independent escape of Listeria monocytogenes from a primary vacuole in human epithelial cells [15].
• The metalloprotease of Listeria monocytogenes controls cell wall translocation of the broad-range phospholipase C [16].
• Chromatographic analysis revealed that phospholipase C splits sphingomyelin in the membrane of sheep erythrocytes [17].
• Pathogenicity of the isolates was tested by Christie, Atkins, Munch Petersen test, phosphotidylinositol-specific phospholipase C assay, mice inoculation test and chick embryo bioassay [18].

Associations of plcB with chemical compounds

• The bacterium secretes a phospholipase C (PLC(LM)) that is active on glycerophospholipids, e.g., phosphatidylcholine, and on sphingomyelin; thus, PLC(LM) should be described more appropriately as a phospholipase C/sphingomyelinase [8].
• Modeling of the 2-O-methylinositol derivative suggests that the methyl group blocks one side of the phosphate, consistent with the observation that nonspecific phospholipase C enzymes which are able to hydrolyze PI, albeit poorly, are unable to hydrolyze diheptanoylphosphatidyl-2-O-methylinositol [12].
• By using the hly-based system as an in vivo expression technology tool, nine in vivo-induced loci of L. monocytogenes were identified, including genes encoding (i) the previously known in vivo-inducible phosphatidylinositol phospholipase C and (ii) a putative N-acetylglucosamine epimerase, possibly involved in teichoic acid biosynthesis [19].
• Chromogenic media are based on both the specific chromogenic detection of phosphatidylinositol phospholipase C and the xylose fermentation and give specific and direct identification of L. monocytogenes and L. ivanovii [20].

Other interactions of plcB

• NDV F or its truncated fragment Fa was used as the model heterologous gene to be integrated into actA or plcB downstream of their signal sequences [1].
• In order to avoid a possible failure in the detection of virulent L. monocytogenes, a one-step procedure which enabled demonstration of three virulence-associated genes, prfA, hlyA, and plcB, simultaneously in a single PCR mixture was developed [21].
• All L. monocytogenes isolates tested positive for the presence of 3 major virulence factors (hlyA, inlB, and plcB) [22].
• Significantly decreased transcription of the plcA gene, encoding a phospholipase C involved in vacuolar escape and cell-to-cell spread, was observed in acid-adapted bacteria [23].

Analytical, diagnostic and therapeutic context of plcB

• Western immunoblot analysis using a rabbit immune serum raised against the enzyme showed that all virulent strains of L. monocytogenes tested produced in the culture supernatant a 29-kDa PLC [24].
• Detection of phospholipase C enzymatic activity was carried out using thin-layer chromatography to detect diglycerides in the hydrolysates of radiolabeled phosphatidylcholine [4].

References