Dictionary > Streptolysin O

Streptolysin O

Definition
noun
An oxygen-labile, immunogenic hemolysin produced by or derived from some strains of streptococci
Supplement
A streptolysin is a type of hemolysin (hemolytic exotoxin, in particular) produced by or derived from some strains of streptococci. A streptolysin may be streptolysin O or streptolysin S. In 1930s, E. W. Todd was able to identify these two toxins responsible for the ability of group A streptococcus to lyse the erythrocytes of mammals.1 Streptolysin O is oxygen-labile whereas streptolysin S is oxygen-stable. 2
Streptolysin O is an oxygen-labile β-hemolytic enzyme belonging to a family of thiol-activated toxins. It is produced by and isolated from groups A, C and G streptococci. This cytolysin is capable of causing lysis in animal cells especially WBCs and RBCs by binding to the membrane cholesterol where it polymerizes to form a transmembrane channel (about 30 nm in diameter), which then leads to cell lysis. Thus, streptolysin O is a potent cell poison responsible for the lysis of WBCs and RBCs. It is also cardiotoxic. It causes changes in myocardial contractility and affects the cardiac conduction system.
Because streptolysin O is immunogenic, it may serve as an antigenic compound used as a basis in antistreptolysin O (ASO) test to diagnose infection with group A Streptococcus bacteria.
Word origin: strepto– from Streptococcus + (hemo)lysin)
See also:

Reference(s):

1 Wessels, M. R. (2005). Streptolysin S. The Journal of Infectious Diseases, 192 (1): 13–15. https://doi.org/10.1086/430625

2 Sierig, G., Cywes, C., Wessels, M. R., & Ashbaugh, C. D. (2003). “Cytotoxic effects of streptolysin o and streptolysin s enhance the virulence of poorly encapsulated group a streptococci”. Infect. Immun. 71 (1): 446–55


You will also like...

running freshwater community
Running Water Freshwater Community Factors

This tutorial noted some of the physical and chemical factors that provide the framework of a running water community in..

Chromosome Mutations
Chromosome Mutations

Mutations can also influence the phenotype of an organism. This tutorial looks at the effects of chromosomal mutations, ..

Ecological Research Measuring & Analysis
Ecological Research: Measuring & Analysis

This lesson is about the methods used for ecological research, such as quadrat and transect sampling, canopy fogging, an..

Principles of Hormonal Control Systems
Principles of Hormonal Control Systems

Hormones are essential in the regulation of the activity of the various biological systems of the human body. The ineffi..

Plant Auxins
Plant Auxins – Phototropism & Geotropism

Plants produce hormones to regulate their growth. Auxins, for instance, influence plant growth. Know the role of auxin i..

Oligodendrocyte and Schwann cell
The Central Nervous System

Myelin sheath is essential for a faster conductivity of signals. Know more about this feature of some neurons in the Cen..

Related Articles...

No related articles found

See all Related Topics