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The hemolysis of some weakly beta-hemolytic organisms is enhanced when streaked close to certain beta hemolytic strains of Staphylococcus aureus. This phenomenon is the mechanism behind the CAMP test , [ 2 ] a test that was historically used for the identification of Streptococcus agalactiae and Listeria monocytogenes . [ 3 ]
Alpha-hemolytic species cause oxidization of iron in hemoglobin molecules within red blood cells, giving it a greenish color on blood agar. Beta-hemolytic species cause complete rupture of red blood cells. On blood agar, this appears as wide areas clear of blood cells surrounding bacterial colonies. Gamma-hemolytic species cause no hemolysis. [11]
A red blood cell in a hypotonic solution, causing water to move into the cell A red blood cell in a hypertonic solution, causing water to move out of the cell. Hemolysis or haemolysis (/ h iː ˈ m ɒ l ɪ s ɪ s /), [1] also known by several other names, is the rupturing of red blood cells (erythrocytes) and the release of their contents into surrounding fluid (e.g. blood plasma).
In colonial morphology, hemolysis is classified into three types: alpha-, beta-, and gamma-hemolysis. In alpha-hemolysis, the blood is partially digested, causing the area around the colony to turn green. In beta-hemolysis, the organism digests the blood completely, leaving a clear area around each colony. [1]: 165–6 Organisms that do not ...
At the moment, apiegnin and beta-cyclodextrin are thought to alleviate S. aureus pneumonia, whereas the antibodies of anti alpha-hemolysin are thought to give protection. [ 17 ] Further findings show that the main virulence factor of S. aureus , the pore-forming toxin α-hemolysin (Hla), is the secreted factor responsible for the activation of ...
Four toxins have been isolated from C. septicum: the lethal alpha toxin, DNase beta-toxin, hyaluronidase gamma toxin, and the thiol-activated (or septicolysin) delta toxin. [10] Alpha toxin causes intravascular hemolysis and tissue necrosis and is well known as the main virulent factor in C. septicum. [9]
Most strains are gamma-hemolytic (non-hemolytic), but some also display alpha-hemolytic activity on sheep blood agar plates. Strep bovis is a non-enterococci. [citation needed] Biochemical Tests mannitol salt: negative bile esculin: negative MR/VP: positive/negative nutrient gelatin: negative starch: positive DNase: negative [citation needed]
This toxin consists mostly of beta sheets (68%) with only about 10% alpha helices. The hly gene on the S. aureus chromosome encodes the 293 residue protein monomer, which forms heptameric units on the cellular membrane to form a complete beta barrel pore. This structure allows the toxin to perform its major function, development of pores in the ...