کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
3398420 1222285 2008 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Role of structural variations of polysaccharide antigens in the pathogenicity of Gram-negative bacteria
موضوعات مرتبط
علوم زیستی و بیوفناوری ایمنی شناسی و میکروب شناسی میکروب شناسی
پیش نمایش صفحه اول مقاله
Role of structural variations of polysaccharide antigens in the pathogenicity of Gram-negative bacteria
چکیده انگلیسی

Pathogenic bacteria employ many strategies to overcome the host immune system for extended survival and propagation in their hosts. Components of the bacterial outer-membrane play an important role in this process. When invading the host, Gram-negative bacteria often use a strategy, known as phase variation, that involves a reversible change in antigenic determinants, frequently polysaccharides. This means that the genes encoding the outer-membrane antigens undergo reversible changes within repeated simple DNA sequence motifs. The antigenic structure of the bacterial outer-membrane is influenced by the character of the host immune system, as well as by the targets for bacterial invasion. When the selection pressure of the immune system is absent or weak, bacteria can fail to synthesise the outer-membrane antigens, which are not needed at that time. Smooth-to-rough (S-R) mutation, an economical and often irreversible process in some Gram-negative bacteria, involves the gradual shortening of the lipopolysaccharide (LPS) O-chain. Under certain conditions, e.g., propagation in embryonated eggs or cell lines, some bacteria will cease synthesis of the complete LPS O-chain because it is an energy-demanding process. A type of gradual shortening of the LPS O-chain by Coxiella burnetii, traditionally called phase variation, is used in serological tests for the diagnosis of Q fever. This review discusses the role and function of polysaccharides, especially LPS produced by some Gram-negative bacteria, in bacterial survival.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Clinical Microbiology and Infection - Volume 14, Issue 3, March 2008, Pages 200–206
نویسندگان
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