Microbial Physiology notes lec10 10-15-10

Microbial Physiology notes lec10 10-15-10 - Microbial...

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Microbial Physiology Lecture 10: October 15, 2010 Bacterial Adhesins (lectins/ carbohydrate binding proteins) 3 types: 1. outer envelope proteins adhesins which are synthesized w/in the cell, and then secreted, and become attached via numerous mechanisms to the cell surface and they contain binding sites for specific proteins/ carbohydrates/glycolipids/ glycoproteins in which they serve as simple adhesins, where they’re just 1 molecule which is responsible for adhesive property of bacteria 2. rigid rod-like Fimbriae consists of protein subunits that form a helical array, and at the end of the helical array there is a lectin (which is a carbohydrate binding protein) or some other type of an adhesin protein, but usually it’s a lectin this then serves as an organelle of attachment to allow the bacteria to attach to a surface—like human intestinal epithelial cells/ another bacteria 3. flexible helical Fimbriae similar to rigid rod like Fimbriae except instead of rigid, its flexible structure which can waves around in medium on the external surface of bacteria it has an adhesin attached at the tip of the flexible structure the flexible structure is called the fibrillum -Compound Fimbriae: has an anchor in the membrane then have a rigid rod which extends the adhesin away from the surface o it can recognize molecules at a distance, and allow the bacteria to adhere to it but it can also be a solid substrate that is being recognized also, or another cell if fimbriae is used for conjugation called a pilus if fimbriae is used for simple adhesion ( regardless if its homotypic/ heterotypic) its called a fimbrium then after having the rod structure, then you have a connector(adaptor), and then you have a fibrillum rigid structure which is the rod structure connector flexible structure which is the fibrillum at the tip of the flexible structure you have the adhesin ( the protein which usually recognizes a carbohydrate like a glycol-lipid/glycoprotein) Narrow host range pathogen : Helical pylori ( H. pylori) bacteria causes ulcers and stomach cancer Very resistant to acid stress, it has to be because the stomach is very acidic
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It only has 1 adhesin the adhesin is specific for a carbohydrate fucose the C-terminal residue of the glycoprotein/glycolipid of the stomach cells (keratinocytes) has to be a fucose residue fucose is found in the blood group residues type O blood has fucose residues at the C-terminal position on your blood group sample Lewis blood group substances also has C-terminal fucose residues on the terminal position o Blood groups are genetically determined, some are type A, B. or type O, or AB o So if an individual isn’t type O blood, then they don’t have a fucose residue at the C-terminal position of their blood group o Some people have the lewis blood group, and some people do the people who do have the lewis blood group then also have the
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This note was uploaded on 01/09/2011 for the course BIMM 130 taught by Professor Saier during the Fall '10 term at UCSD.

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Microbial Physiology notes lec10 10-15-10 - Microbial...

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