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O antigen

Definition

noun

(microbiology) A repetitive glycan polymer attached to the core oligosaccharide of the LPS layer of certain bacteria; a somatic antigen that comprises the outermost domain of the lipopolysaccharide

(immunology) A major blood group antigen indicating the presence of H antigen and the lack of additional antigens, particularly N-Acetylgalactosamine (found in A antigen) and galactose (in B antigen)


Supplement

In microbiology, O antigen renders additional protection from the antimicrobial action of certain antibiotics. Without it, the LPS becomes hydrophobic and therefore is more susceptible to the action of hydrophobic antibiotics. 1

In immunology, blood types are determined by the presence of blood-group antigens. In humas, there are three types of blood-group antigens, namely H antigen, A antigen, and B antigen. They differ basically on structural component.


Synonym(s):

  • (microbiology) O polysaccharide
  • (microbiology) O side-chain

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See also:

Reference(s):

  • 1Tsujimoto H et al. (2003). "Diffusion of macrolide antibiotics through the outer membrane of Moraxella catarrhalis". Journal of Infection and Chemotherapy 74 (4): 1045–1055. doi:10.1007/s101569900025

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An Investigation of ABO Group Antigen Structure question?

Group O red blood cells have been incubated with either UDP-galactose or UDP-N- acetyl galactosamine together with group A, group B or group O serum for six hours at 37oC as follows: Tube 1 Group O cells UDP-NacG O-serum Tube 2 Group O cells UDP-Gal O-serum Tube 3 Group O cells UDP-NacG B-serum Tube...

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by revision
Fri Feb 07, 2014 8:17 pm
 
Forum: Molecular Biology
Topic: An Investigation of ABO Group Antigen Structure question?
Replies: 1
Views: 1426

Blood Genetics help please

The A, B and O antigens of the human blood system are sugars that can be found on the surface of red blood cells. The alleles A, B and O refer to the variant forms of the proteins (enzymes) that produce the sugar antigens. The O ...

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by girlslovebarbie
Sat Feb 01, 2014 2:58 pm
 
Forum: Genetics
Topic: Blood Genetics help please
Replies: 2
Views: 2086

I Need Help understanding gametes, genotypes and phenotypes

... which involves alleles (denoted h & H) in another part of the genome. Individuals with the rare Bombay phenotype (hh) do not express H antigen (also called substance H), the antigen which is present in blood group O. As a result, they cannot make A antigen (also called substance A) ...

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by wildfunguy
Tue Oct 29, 2013 3:25 pm
 
Forum: Genetics
Topic: I Need Help understanding gametes, genotypes and phenotypes
Replies: 5
Views: 3821

selective advantage for certain blood groups

... guyton's textbook of medical physio, type O- 47%, A- 41%, B-9%, AB-3%). a quick search online revealed minor selective factors like the Duffy antigen receptor being recognised by the malarial parasites etc. but why does the major blood type (ABO) have the large variation in frequency as quoted ...

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by TYLS
Thu Oct 10, 2013 1:16 pm
 
Forum: Human Biology
Topic: selective advantage for certain blood groups
Replies: 1
Views: 966

Antibody Coating

How Do I coat a antigen specific antibody on the surface of the Micro triter plate ? please Share any Link.

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by Helics
Fri Aug 02, 2013 7:56 pm
 
Forum: Microbiology
Topic: Antibody Coating
Replies: 1
Views: 983
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