The antibacterial protein Colicin V (ColV) is secreted from gram-negative bacteria by a signal sequence-independent pathway. The proteins that mediate the export of ColV share sequence similarities with components from other signal sequence-independent export systems such as those for alpha-hemolysin (Hly) and Erwinia protease (Prt). We report here that the intact HlyBD export system can export...

A genomic library constructed from Renibacterium salmoninarum isolate MT444 DNA in the plasmid vector pBR328 was screened using Escherichia coli host strain DH1 for the expression of genes encoding putative virulence factors. A single haemolytic clone was isolated at 22 degrees C and found to contain a 3.1 kb HindIII fragment of inserted DNA. This fragment was present in seven isolates of R. sa...

Potential virulence, as defined by combined levels of adhesion to urinary epithelial cells, serum resistance, and mouse toxicity, was assessed for Escherichia coli strains causing symptomatic and asymptomatic urinary tract infections in relation to the carriage of hemolysin and other suspected virulence determinants. Hemolysin production (Hly), associated with certain O (O4, O6, O18, and O75), ...

We have examined the human humoral immune response directed against proteins of Listeria monocytogenes in both healthy individuals and listeriosis patients. Two major targets for an antibody response were found in individuals that did not suffer from listeriosis: listeriolysin (Hly) and the recently described internalin-related protein (IrpA). In contrast, the humoral response in listeriosis pa...

Two hybrid clones producing monoclonal antibodies (MAbs) raised against the purified enterotoxic hemolysin-phospholipase C (HlyPC) bifunctional molecule of a Vibrio cholerae O139 strain were used to study its enterotoxicity in relation to its hemolytic and enzymatic activities. Fab fragments of MAbs from ascites produced by the two hybrids neutralized the hemolytic activity of HlyPC, leaving th...

Listeria monocytogenes is a facultative intracellular pathogen which enters cells by endocytosis and reaches phagolysosomes from where it escapes and multiplies in the cytosol of untreated cells. Exposure of macrophages to gamma interferon (IFN-gamma) restricts L. monocytogenes to phagosomes and prevents its intracellular multiplication. We have tested whether IFN-gamma also modulates the susce...

We describe purification and characterization of an oligopeptide permease protein (Hly-OppA) from Vibrio furnissii that has multifaceted functions in solute binding, in in vitro hemolysis, in antibiotic resistance, and as a virulence factor in bacterial pathogenesis. The solute-binding function was revealed by N-terminal and internal peptide sequences of the purified protein and was confirmed b...

The alpha-hemolysin structural gene, hly+, previously cloned, insertionally inactivated, and introduced into the chromosome by allele replacement (M.O. O'Reilly, J.C.S. De Azavedo, S. Kennedy, and T.J. Foster, Microb. Pathog. 1:125-138, 1986), was shown by protoplast fusion and transformation to be in the gene order purC-hly-uraB-omega[chr::Tn916]1101-thrB on the chromosome of Staphylococcus au...

A simple method for the nontoxic, specific, and efficient secretion of active single-chain Fv antibodies (scFvs) into the supernatants of Escherichia coli cultures is reported. The method is based on the well-characterized hemolysin transport system (Hly) of E. coli that specifically secretes the target protein from the bacterial cytoplasm into the extracellular medium without a periplasmic int...