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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 ]
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 ...
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).
Compared to beta-hemolysin, it has a higher affinity for phosphocholines with short saturated acyl chains, especially if they have a conical form, whereas cylindrical lipids (e.g., sphingomyelin) hinder its activity. The lytic process, most commonly seen in leucocytes, is caused by pore formation induced by an oligomerized octamer that ...
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]
IgA has the most anodal mobility and typically migrates in the region between the beta and gamma zones also causing a beta/gamma fusion in patients with cirrhosis, respiratory infection, skin disease, or rheumatoid arthritis (increased IgA). Fibrinogen from plasma samples will be seen in the beta gamma region. Fibrinogen, a beta-2 protein, is ...
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 ...
Its alpha-helical, amphipathic structure gives it detergent-like properties, allowing it to disrupt and attach to the cytoplasmic membrane of a cell non-specifically, without a receptor, and integrate into the membrane. [4] [5] Delta toxin degrades the membrane on contact and forms short-lived pores, causing cell lysis and subsequent cell death ...