Is lipopolysaccarides in gram negative bacteria are present in outer membrane of cell wall?

Answer 1

Yes.

Answer 2

Yes.
the outer membrane is a bilayered structure consisting of phospholipids, proteins and lipopolysaccharrides
Presence of lipopolysaccharide makes the gram negative bacteria Pathogenic. Amount of Lipopolysaccharide in Gram Negative bacteria may account to about 30-40 % approximately. It accounts for the endotoxic property and O antigen Specificity.
When the bacteria is decolurised by the 70% ethanol, they are solubilsed and as a result open pores are formed .these pores retain the saffranin stain when stained during gram staining procedure giving the pink colour.

Answer 3

The increasing resistance of bacteria to conventional antibiotics resulted in a strong effort to develop antimicrobial compounds with new mechanisms of action. Antimicrobial peptides seem to be a promising solution to this problem. Many studies aimed at understanding their mode of action were described in the past few years. The most studied group includes the linear, mostly -helical peptides. Although the exact mechanism by which they kill bacteria is not clearly understood, it has been shown that peptide-lipid interactions leading to membrane permeation play a role in their activity. Membrane permeation by amphipathic -helical peptides can proceed via either one of the two mechanisms: (a) transmembrane pore formation via a barrel-stave mechanism; and (b) membrane destruction/solubilization via a carpet-like mechanism. The purpose of this review is to summarize recent studies aimed at understanding the mode of action of linear -helical antimicrobial peptides. This review, which is focused on magainins, cecropins, and dermaseptins as representatives of the amphipathic -helical antimicrobial peptides, supports the carpet-like rather the barrel-stave mechanism. That these peptides vary with regard to their length, amino acid composition, and net positive charge, but act via a common mechanism, may imply that other linear antimicrobial peptides that share the same properties also share the same mechanism.

Answer 4

lipoplysaccarides(LPS) present on the outer cell walls of Gram negative bacteria(in Gram positive bacteria it is absent or scanty)and account for their endotoxic activity and O antigen speceficity.
they were formerly known as the :
BOIVIN ANTIGEN

Answer 5

Yes. http://www.ppws.vt.edu/~sforza/prokaryote/cell_walls.html

This expains how you can figure out the answer: http://www-micro.msb.le.ac.uk/video/Gram.html Basically, the lipopolysaccaride layer prevents the purple crystal violet stain from penetrating the peptidoglycan layer which retains the purple color, differentiating the gram positive (purple after staining) from the gram negative (pink after staining) bacteria.

Answer 6

ya obviously there is ,
gram -ve r mostly pathogenic.
So it only prevents the gram -ve bacteria from the immunity of the body when they enter in the body.

Answer 7

yes lipopolysaccharides are present in gram -ve bacteria like all enterobacter.

Answer 8

yes

Answer 9

ya