Escherichia coli α-hemolysin (HlyA) is a pore-forming protein of 110 kDa belonging to the family of RTX toxins. A hydrophobic region between the amino acid residues 238 and 410 in the N-terminal half of HlyA has previously been suggested to form hydrophobic and/or amphipathic α-helices and has been shown to be important for hemolytic activity and pore formation in biological and artificial memb...

OBJECTIVE To investigate whether the HlyA-induced vacuolating effect is produced by V. cholerae O1 ElTor strains isolated from different geographic origins, including Mexico. MATERIAL AND METHODS Supernatant-induced haemolysis, vacuolating activity and cytotoxicity in Vero cells were recorded. PCR, RFLP analysis and molecular cloning were performed. RESULTS All ElTor strains analyzed induce...

Alpha-hemolysin (HlyA) is an extracellular toxin secreted by Escherichia coli, targeting to plasma membranes of eukaryotic cells. Recently it was found that this toxin is released to external media associated to bacterial outer membrane vesicles (OMVs), but the hemolytic mechanism in this way has not been studied yet. Our results report that HlyA is the only protein present in OMVs that is resp...

Lipopolysaccharides (LPS) of gram-negative bacteria prime rabbit lungs for enhanced thromboxane-mediated vasoconstriction upon subsequent challenge with the exotoxin Escherichia coli hemolysin (HlyA) (Walmrath et al. J. Exp. Med. 1994;180:1437-1443). We investigated the impact of endotoxin priming and subsequent HlyA challenge on lung vascular permeability while maintaining constancy of capilla...

Production of a single cysteine substitution mutant, S177C, allowed Escherichia coli hemolysin (HlyA) to be radioactively labeled with tritiated N-ethylmaleimide without affecting biological activity. It thus became possible to study the binding characteristics of HlyA as well as of toxin mutants in which one or both acylation sites were deleted. All toxins bound to erythrocytes and granulocyte...

Hemolysin (HlyA) produced by some stains of Escherichia coli is considered to be an important virulence factor of those bacteria. On the other hand, reactive oxygen species (ROS) have been reported to be involved in the pathogenesis of different diseases via oxidative stress generation. The purpose of this study was to analyze the capacity of HlyA to induce oxidative stress in whole blood cultu...

Type 1 secretion systems (T1SS) of Gram-negative bacteria are responsible for the secretion of various proteases, lipases, S-layer proteins or toxins into the extracellular space. The paradigm of these systems is the hemolysin A (HlyA) T1SS of Escherichia coli. This multiple membrane protein complex is able to secrete the toxin HlyA in one step across both E. coli membranes. Common to all secre...

Type 1 secretion systems (T1SS) of Gram-negative bacteria are responsible for the secretion of various proteases, lipases, S-layer proteins or toxins into the extracellular space. The paradigm of these systems is the hemolysin A (HlyA) T1SS of Escherichia coli. This multiple membrane protein complex is able to secrete the toxin HlyA in one step across both E. coli membranes. Common to all secre...

BACKGROUND & OBJECTIVES Limited information is available on shiga toxin producing Escherichia coli (STEC) in animals and birds from India. An outbreak of acute diarrhoea in poultry birds at Aizawl, Mizoram was investigated for detection and characterization of STEC and enteropathogenic E. coli (EPEC). METHODS E. coli was isolated and identified from rectal swabs, intestinal contents, heart bl...

Secretion of the 107-kDa hemolysin A (HlyA) from Escherichia coli is mediated by the membrane proteins hemolysin B and hemolysin D. Hemolysin B is a member of the so-called ATP binding cassette transporter superfamily, which includes the multidrug resistance P-glycoprotein, the cystic fibrosis CFTR protein, and the major histocompatibility complex-associated transporter of antigenic peptides. R...