The hemolysin of escherichia coli

  title={The hemolysin of escherichia coli},
  author={Sucharit Bhakdi and Nigel Mackman and Gianfranco Menestrina and Lindsay Gray and Ferdinand Hugo and Werner Seeger and I. Barry Holland},
  journal={European Journal of Epidemiology},
Many strains of E. coli elaborate a hemolysin which is responsible for the zone of β-hemolysis surrounding bacterial colonies on blood agar. The significance of this cytolysin as a determinant of bacterial pathogenicity has been established in animal models with the use of genetically engineered, isogenic bacterial strains. An analogous role in human infections has been inferred from the high association of hemolysin production with disease. Studies at a molecular genetical level have defined 4… 

Efficient production of endotoxin depleted bioactive α-hemolysin of uropathogenic Escherichia coli

This is the first report of the production of active and inactive recombinant α-hemolysin for functional studies, by cloning only hlyA and HlyC genes of operon hlyCABD of Uropathogenic E. coli.

α-Hemolysin from Escherichia coli uses endogenous amplification through P2X receptor activation to induce hemolysis

Escherichia coli is the dominant facultative bacterium in the normal intestinal flora. E. coli is, however, also responsible for the majority of serious extraintestinal infections. There are distinct

Screening and purification of nanobodies from E. coli culture supernatants using the hemolysin secretion system

The data demonstrate the Hly secretion system of E. coli can be used as an expression platform for screening and purification of Nb binders from VHH repertories, and shows that the secreted Nb-HlyA fusions can be directly purified from the supernatant ofE.

α‐Haemolysin production, as a single factor, causes fulminant sepsis in a model of Escherichia coli‐induced bacteraemia

It is shown that HlyA accelerates the host response to E. coli in the circulation and is a virulence factor that accelerates a state of bacteraemia into fulminant sepsis in a mouse model.

P2X Receptor-Dependent Erythrocyte Damage by α-Hemolysin from Escherichia coli Triggers Phagocytosis by THP-1 Cells

The pore‐forming exotoxin α‐hemolysin from E. coli causes a significant volume reduction of human erythrocytes that precedes the ultimate swelling and lysis and increased exposure of phosphatidyl‐serine in the outer plasma membrane leaflet, which is known to be a keen trigger for phagocytosis.

Inactivation of host Akt/protein kinase B signaling by bacterial pore-forming toxins.

HlyA can potently inhibit activation of Akt (protein kinase B), a key regulator of host cell survival, inflammatory responses, proliferation, and metabolism, and this data suggest a novel mechanism by which sublytic concentrations of HlyA and other pore-forming toxins can modulatehost cell survival and inflammatory pathways during the course of a bacterial infection.

RegA, an AraC-Like Protein, Is a Global Transcriptional Regulator That Controls Virulence Gene Expression in Citrobacter rodentium

Results show that RegA is a global regulator of virulence in C. rodentium which activates factors that are required for intestinal colonization.

Bacteria differentially induce degradation of Bcl-xL, a survival protein, by human platelets.

This work demonstrates that pathogenic bacteria induce apoptotic events in platelets that include calpain-mediated degradation of Bcl-x(L), an essential regulator of platelet survival, and suggests a new mechanism by which bacterial pathogens might cause thrombocytopenia in patients with bloodstream infections.

Escherichia coli α-Hemolysin Triggers Shrinkage of Erythrocytes via KCa3.1 and TMEM16A Channels with Subsequent Phosphatidylserine Exposure*

This study shows that HlyA triggers acute erythrocyte shrinkage, which depends on Ca2+-activated efflux of K+ via KCa3.1 and Cl− via TMEM16A, with subsequent phosphatidylserine exposure.



Escherichia coli hemolysin is released extracellularly without cleavage of a signal peptide

These studies demonstrated how hemolysin-associated 110- and 58-kilodalton polypeptides detected in the minicell background could be misinterpreted as a precursor-product relationship.

Purification of α-hemolysin from an overproducing E. coli strain

α-hemolysin was purified from culture supernatants of strain SU100 by ammonium sulfate precipitation and gel filtration in Sephacryl S-200 in the presence of 6 M urea and, when subjected to electrophoretic analysis in denaturing conditions, a single 107 kdal polypeptide was observed.

Characterization of Escherichia coli hemolysins conferring quantitative differences in virulence

The region conferring quantitative differences in extracellular hemolysin production and virulence was found to be within a region of less than 1 kilobase where the hly c cistron is encoded as well as the probable transcription initiation ares for the entire hemoly sin operon.

Properties of the Hemolytic Activities of Escherichia coli

The kinetics of the lytic reaction are most consistent with the hypothesis that one molecule of cell-free hemolysin is sufficient to lyse one erythrocyte and that it is inactivated in the Lytic reaction.

Genetics of hemolysin of Escherichia coli

The genetic basis for hemolysin expression by an E. coli strain isolated from a human urinary tract infection was examined and Hemolysin was found to be necessary but not in itself sufficient for E. bacteria virulence in this in vitro model.

Synthesis and secretion of hemolysin by Escherichia coli

Hemolytic Escherichia coli cells were found to synthesize and secrete significant amounts of hemolysin into a mineral salt-glucose medium containing hemoglobin, and it was concluded that two transport processes are involved in hemoly sin secretion.

Transport of hemolysin across the outer membrane of Escherichia coli requires two functions

It is shown that the phenotypic appearance of colonies from hlyBb mutants is that of beta-hemolytic Escherichia coli strains, indicating that a substantial portion of hemolysin has already reached the outside of the outer membrane without being released into the medium.

Chemical and immunological analysis of the complex structure of Escherichia coli alpha-hemolysin

Findings suggest several possible mechanisms for release of AH from the bacterial cell including release by outer membrane fragmentation, and the existence of AH complexed with lipopolysaccharide may have important implications in understanding its toxicity.

Molecular cloning and physical characterization of a chromosomal hemolysin from Escherichia coli

Seventeen hemolytic E. coli isolates from human urinary tract infections were found to share similar DNA sequences with J96 hemolysin sequences, using a hemoly sin-specific restriction endonuclease fragment as a hybridization probe, suggesting that in the evolutionary sense the hemolySin-specific genetic sequences have only recently been introduced into the E. bacteria.

Cloning and functional characterization of the plasmid-encoded hemolysin determinant of Escherichia coli

It is shown that overproduction of the hlyA product is lethal, probably causing lysis of the cell, and the function of each of the gene products in the production and transport of hemolysin is partially characterized.