It is so dense that it is someames called a protein

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: covalently to the pepAdoglycan by an enzyme called sortase. Teichoic acid 42 Brock Biology of Microorganisms, 13th EdiAon. Cell wall of Gram- negaAve bacteria 43 Brock Biology of Microorganisms, 13th EdiAon. Cell wall of Gram- negaAve bacteria •  PepAdoglycan: 5- 10% of the cell wall. •  The pepAdoglycan is located in the periplasm, the space delimited by the cytoplasmic membrane and the outer membrane. The periplasm contains a high concentraAon of proteins involved in diverse of funcAons, such as nutrient acquisiAon, extracellular enzymaAc reacAons, sensing, etc. It is so dense that it is someAmes called a “protein gel”. •  The outer membrane is an atypical lipid bilayer: phospholipids in the inside layer, phospholipids and lipopolysaccharide in the outside layer (LPS layer). •  The LPS helps protect the bacteria against a variety of substances, including anAbioAcs, and against the host defense system. •  The outer membrane also contains outer membrane proteins (OMPs), such as porins, and lipoproteins which play a structural role. 44 LPS of Gram- negaAve bacteria •  LPS is a family of complex sugar polymers abached to a lipid moiety known as lipid A. Lipid A is toxic to many animals, it can cause acute inflammaAon and vascular problems (sepAc shock) that can result in death. Lipid A is an endotoxin and it plays a major role in the pathogenesis of Gram- negaAve bacterial pathogens. Lipid A contains 6 lipid tails that are embedded in the membrane. KDO: 2- keto- deoxyoctonate, links the lipid A to the polysaccharide chain. •  O- specific polysaccharide, also known as the O anAgen, consists of repeaAng sequences of 2- 4 monosaccharides. Huge diversity of O anAgens so it can be used to idenAfy different strains of one species of bacteria: ex: E. coli O157:H7 (O157 serogroup). 45 Brock Biology of Microorganisms, 13th EdiAon....
View Full Document

This note was uploaded on 03/20/2014 for the course PSYC 101 taught by Professor Catone during the Spring '07 term at CSU Fullerton.

Ask a homework question - tutors are online