![]() The various glaring comparative activities of both Gram-negative and Gram-positive bacteria are enumerated below : (iv) Lipopolysaccharides represent the major antigenic determinants, and also the receptors for the active adsorption of several bacteriophages.Ĭomparative Activities of Gram-negative and Gram-positive Bacteria (iii) The ‘core region’ comprises of a short-chain of carbohydrates, and the O-side chain consists of different carbohydrates and is much longer in comparison to the R-core region. ![]() (ii) The ‘lipid zone’ comprises of a phosphorylated glucosamine disaccharide esterified adequately with long chain fatty acids. (i) The various subunits in lipopolysaccharide are duly linked via pyrophosphates with the ‘lipid zone’. 2.13.Įxplanations : The proper explanations for the various transformations occurring in Figure : 2.13 are as given below : necessarily comprise of subunits, and each subunit consists of three vital compo-nents, namely : ( a) a lipid ( b) core region and ( c) O-side chain respectively, as given in Fig. Typical Example : It has been observed that the lipopolysaccharides belonging to either E. 10) and, therefore, these are markedly distinct from those invari-ably found in the inner membrane. (5) The total number of proteins definitely present, unlike in the inner membrane, are quite a few in number (approx. (4) Lipoproteins evidently serve as a sort of bridge right from the peptidoglycan upto the outer-wall-layer. The peptidoglycan of the wall has particular kinds of lipoproteins residing on its outer surface, that are strategically linked by peptide bonds to certain diaminopimelic acid residues present in the peptidoglycan. Besides, the lipopolysaccharide generates the major component of the outer membrane, and represents an extremely complex molecule varying in chemical composition within/between the Gram –ve bacteria. The fine structure of the outer membrane, very much akin to cell mem-brane, essentially comprises of a lipid bilayer wherein both phospholipids and lipopolysaccharides are definitely present. (1) Peptidoglycans belonging to the Gram –ve microorganisms exhibits a rather low extent of cross linkages within the glycan strands. Principal Chemical Differences Existing Between Cell Walls of Gram-positive and Gram-negative BacteriaĬardinal characteristic features of component variants in Gram +ve and Gram –ve micro-organisms : The various important characteristic features of component variants in Gram +ve and Gram –ve microbes are as stated under : The principal chemical differences that predominently occur between the cell walls of Gram-positive bacteria and the inner rigid wall layer and outer wall layer(s) of Gram-negative bacteria have been duly summarized in Table 2.8 given below : ![]() Importantly, the peptidoglycan is prominently confined to the inner layer whereas, the outer layer (membrane) essentially comprises of proteins, lipoproteins, and lipopolysaccharides. (b) A thicker outer layer nearly 8–10 nm wide. (a) An uniform inner layer approximately 2–3 mm wide, and There are two distinct layers that have been duly recognized in the cell envelopes of Gram-negative bacteria, namely : The various characteristic features of Gram-positive and Gram-negative bacteria shall be dis-cussed at length in this particular section.įor Gram-negative bacteria.
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