What does alpha-hemolysin do?

Published by Charlie Davidson on

What does alpha-hemolysin do?

alpha-Hemolysin from Staphylococcus aureus assembles from a water-soluble, monomeric species to a membrane-bound heptamer on the surface of target cells, creating water-filled channels that lead to cell death and lysis.

What type of toxin is the alpha-hemolysin of Staphylococcus aureus?

Alpha-toxin, also known as alpha-hemolysin (Hla), is the major cytotoxic agent released by bacterium Staphylococcus aureus and the first identified member of the pore forming beta-barrel toxin family….Staphylococcus aureus alpha toxin.

UniProt P09616
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What are the effects of the beta hemolysin produced by Staphylococcus aureus?

Epidemiological studies demonstrate that β-toxin contributes to the recurrence of S. aureus furunculosis, chronic osteomyelitis, and respiratory infections in humans [19, 20], and to the development of ocular keratitis [21] and mastitis [22] in animals.

What toxins are produced by staphylococcus?

Amongst the more common toxins secreted by S. aureus are hemolysin, leukotoxin, exfoliative toxin, enterotoxin, and toxic-shock syndrome toxin-1 (TSST-1). Aside from toxins, staphylococcal virulence factors also include enzymes and surface proteins.

What is the function of hemolysin?

Hemolysins or haemolysins are lipids and proteins that cause lysis of red blood cells by disrupting the cell membrane.

Which toxin is a hemolysin?


Leukocidin/Hemolysin toxin
Staphylococcus aureus alpha toxin from S. aureus (PDB: 7AHL​).
Symbol Leukocidin
Pfam PF07968

How do Exotoxins work?

An exotoxin is a toxin secreted by bacteria. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. They are highly potent and can cause major damage to the host. Exotoxins may be secreted, or, similar to endotoxins, may be released during lysis of the cell.

What type of hemolysis is Staphylococcus aureus?

Staphylococcus aureus is a common pathogen causing both hospital and community-acquired infections. Hemolysin is one of the important virulence factors for S. aureus and causes the typical β-hemolytic phenotype which is called complete hemolytic phenotype as well.

Which Staphylococcus is commonly found on the skin?

epidermidis is the staphylococcal species that is most frequently isolated from the human skin [10].

What food causes Staphylococcus?

The foods that have been most frequently implicated in cases of staphylococcal food poisoning are poultry and cooked meat products such as ham or corned beef. Other foods implicated were milk and milk products, canned food and bakery products.

Where is staphylococcus found?

Staph infections are caused by staphylococcus bacteria, types of germs commonly found on the skin or in the nose of even healthy individuals. Most of the time, these bacteria cause no problems or result in relatively minor skin infections.

How does HLA play a role in Staphylococcus aureus pathogenesis?

Cytolytic pore-forming toxins including alpha hemolysin (Hla) and bicomponent leukotoxins play an important role in the pathogenesis of Staphylococcus aureus. These toxins kill the polymorphonuclear phagocytes (PMNs), disrupt epithelial and endothelial barriers, and lyse erythrocytes to provide iron for bacterial growth.

What happens when HlyA is inserted into the cell membrane?

Further study revealed that insertion of HlyA into the cell membrane of epithelial cells and macrophages induces activation of mesotrypsin, a serine protease ( Dhakal and Mulvey, 2012 ).

What kind of repeat in toxin is alpha hemolysin?

Alpha-hemolysin is a prototypical member of the repeat in toxin (RTX) family (Welch, 1991). While deletion of hlyA did not attenuate UPEC in the mouse model of ascending UTI, significantly less sloughing of the uroepithelium and bladder hemorrhage was observed in comparison to wild-type E. coli (Smith et al., 2008).

Which is the structural gene of α hemolysin?

The structural gene of α-hemolysin, hlyA, is clustered with the genes encoding HlyC, HlyB, and HlyD in the hlyCABD operon, while TolC is genetically unlinked ( Felmlee et al., 1985; Hess et al., 1986 ).

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