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teichoic acids

Many Gram-positive Bacteria have acidic polysaccharides called teichoic acids embedded in their cell wall

The amino acids present for pseudomurein

in the L-isoform

The term teichoic acids includes ex

includes all wall, membrane or capsular polymers containing polyalcohols residues Includes glycerol phosphate or ribitol phosphate (spp. dependent) and are negatively charged

S-layer consists of typically have what shape

interlocking protein or glycoprotein Typically have hexagonal symmetry

A major function of the LPS is to

keep proteins from diffusing away

Teichoic acids are negatively charged, therefore they are partially responsible for

the negative charge on Gram-positive cell surface No clear known function

petidoglycan sugars have what kind of bond and can be broken down by

β 1,4 glycosidic bond lysozyme

The sugar N-acetylmuramic acid (M) and the amino acid DAP are never found in the cell walls of

Archaea or Eukarya

Others cells may lose the cell wall, known as

L-form/cell wall deficient (CWD)

Examples of Bacteria with no cell wall:

Mycoplasma: like a protoplast, lives in osmotically protected environments; contain sterols for added strength to membrane

The pseudomurein backbone is composed of alternating repeats of types of bond

N-acetylglucosamine (G) and N-acetyltalosaminuronic acid (T) The glycosidic bonds are β(1,3) instead of β(1,4)

LPS has what 3 parts and what are they made up of

O-specific polysaccharides is the outermost component Core polysaccharides is made up of sugars, including the unusual sugar KDO (2-keto-3-deoxy-octanoate) Lipid portion (Lipid A) has fatty acids linked to N-acetylglucosamine (G) through the amine groups; forms the inner most component

S-layer also called and a present

Paracrystalline Surface Layer Most common cell wall in Archaea May also be found in Bacteria

septicemia present when examples

Presence of the LPS in the blood Examples of bacteria that can lead to septicemia include: Salmonella, Shigella and E. coli

glycan tetrapeptide

When the sugars and amino acids are connected in peptidoglycan they make up the this

Endotoxins can produce

fever, a decrease in blood pressure, activation of inflammation and coagulation of blood

Most Gram-positive bacilli have DAP instead of

lysine

Peptidoglycan can be destroyed by certain agents, such as

lysozyme

can hydrophobic antibiotics effect gram negative bacteria

no because they can't get through the outer-O-specific polysaccharides

Archaea are naturally resistant to

penicillin or lysozyme that destroy peptidoglycan

Teichoic acids are

polyalcohols connected by phosphate esters along with sugars and D-alanine

Gram-positive: produces when treated with lysozyme in an isotonic environment

protoplast

Breakdown of cell wall in a dilute solution releases the but

protoplast but it immediately lyses because the cytoplasmic membrane is very weak

Some Archaea contain cell walls constructed of a polysaccharide very similar to peptidoglycan Known as

pseudomurein

Gram-negative: treatment with lysozyme produces a

spheroplast which is similar to protoplast but has residual wall attached Gram-negative bacteria contain the LPS layer which is not weakened by lysozyme

Lipoteichoic acids (LTA) are

teichoic acids covalently linked to membrane lipids

Another unusual feature of the bacterial cell wall is the presence of two amino acids

that have the D-configuration D-alanine and D-glutamic acid

which portion of LPS is toxic to animals

the lipid A portion the toxicity is termed endotoxin

peptidoglycan composed of

two sugar derivatives, N-acetylglucosamine (G) and N-acetylmuramic acid (M) tetrapeptide side chain consisting of L-alanine, D-glutamic acid, either L-lysine (Gram-positive) diaminopimelic acid (DAP; Gram-negative) and D-alanine

Non specific porins are

water filled channels