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This test is used to measure the contact activation pathway (intrinsic pathway) and the common pathway of clotting. [7] FXII is a zymogen, which means that it requires processing to attain its catalytic protease activity. Upon binding to surfaces, FXII alters in its conformation, giving it low-level protease activity.
Factor XII deficiency is a rare disorder that is inherited in an autosomal recessive manner. [19] Unlike other clotting factor deficiencies, factor XII deficiency is totally asymptomatic and does not cause excess bleeding. [19] Mice lacking the gene for factor XII, however, are less susceptible to thrombosis. The protein seems to be involved in ...
Over time, methods for testing the sensitivity of bacteria to antibiotics have developed and changed. [25] Alexander Fleming in the 1920s developed the first method of susceptibility testing. The "gutter method" that he developed was a diffusion method, involving an antibiotic that was diffused through a gutter made of agar. [25]
This reaction is the basis of the LAL test, which is widely used for the detection and quantification of bacterial endotoxins. In Asia, a similar Tachypleus amebocyte lysate ( TAL ) test based on the local horseshoe crabs Tachypleus gigas or Tachypleus tridentatus is occasionally used instead. [ 1 ]
The hemagglutination assay or haemagglutination assay (HA) and the hemagglutination inhibition assay (HI or HAI) were developed in 1941–42 by American virologist George Hirst as methods for quantifying the relative concentration of viruses, bacteria, or antibodies.
Microbes such as bacteria have been gaining resistance to antimicrobials they were previously susceptible to. [18] Usage of incompatible levels of antimicrobials provides the selective pressure that has driven the direction and evolution of resistance of bacterial pathogens. [19] This has been seen at sub-MIC levels of antibiotics. [20]
FDA hydrolysis is often used to measure activity in soil and compost samples; however, it may not give an accurate reading if microbes with lower activity phases, such as esterases, cleave the fluorescein first. It is also used in combination with propidium iodide (PI) to determine viability in eukaryotic cells. Living cells will actively ...
This method, which is commonly used with Mueller–Hinton agar, is used by evenly seeding bacteria over a petri dish and applying an antibiotic treated disk to the top of the agar. By observing the ring formed around the disk formed due to the lack of bacterial growth, the zone of inhibition can be found, which is used to find the ...