MicroBio - Lecture 1 and Lecture 2 (Prokaryote structure and function)

coccus

spherical or ovoid shape

rod/bacillus

cylindrical shape

spirillum

curved or spiral

spirochetes

tightly coiled shape

appendaged bacteria

bacteria with structures attached to it

filamentous bacteria

thin. long rod shape

most cultured rod-shaped bacteria are between

0.5 and 4.0 micrometers wide and less than 15 micrometers long

advantages of being small

more surface area relative to cell volume, support greater nurtient and waster product exchange per unit cell volume

ultramicrobacteria

small cells (0.2-0.4 micrometers), in open oceans

protein anchor

holds transport proteins in place

Bacteria can change the length and the saturation of

fatty acids

hopanoids

general term for “cholesterol like” stabilizer in bacteria membranes

ether linkages

in phospholipids of archaea

ester linkages

in phospholipids of bacteria and eukarya

isoprenes

“fatty acid” in archaea

Archaea lipids that form bilayer

phosphoglyercerol diethers with phytanyl C20 chains

archaea lipids that form monolayed

diphosphoglycerol tetraethers with biphytanyl C40 side chains

Gram-positive

thicker, primarily one layer of peptidoglycan

gram negative

has two layers: LPS and peptidoglycan

Peptidoglycan

mesh-like polymer composed of alternating N-acetylglucosamine and N-acetylmuramic acid in Beta-1,4 glycosidic linkages

N-acetylglucosamine and N-acetylmuramic acid

alternating modified glucose that make up peptidoglycan

Sheets of Peptidoglycan are cross-linked, which are?

peptide bonds between amino acids, 4 amino acid combinations (bonded to each NAM and NAG)

Amino acids in cross links

L-Alanine, D- glutamic acid, L-Lysine (gram+) or diaminopimelic acid (DAP) (gram-), D-Alanine

Lysozyme

enzymes that cleave glycosidic bond between NAM and NAG

glycine interbridge

Third amino acid in chain is bonded to 5 glycines forming a bridge, which are then connected to the 4 amino acids bonded to the next sheet of NAG and NAM (ONLY IN GRAM +)

teichoic acids

acidic substances covalently bonded to peptidoglycan in gram + bacteria

lipoteichoic acids

covalently bond teichoic acids to membrane lipids

lipopolysaccharide (LPS)

part of cell that serves as a barrier against antibiotics and other harmful agents, consists of core polysaccharide, O-polysaccharide and lipid (ONLY IN GRAM -)

O-specific polysaccharide

can be an antigen, part of LPS

lipid A

can be an endotoxin if it is not broken down and enters the blood stream, part of LPS

periplasm

space located between cytoplasmic and outer membrane

porins

transmembrane protein channels for entrance and exit of solutes

pseudomurein

found in cell walls of certain methanogenic Archaea

composed of N-acetylglucosamine and N-acetylalosaminuronic acid

Beta 1,3 glycosidic bonds

cannot be destroyed by lysozyme or cross linkages synthesis inhibited by penicillin

S layers

in Archaea that lack pseudomurein

consist of protein or glycoprotein

has a paracrystallin structure

Mycoplasma

group of pathogenic bacteria related to gram-positives

thermoplasma

have touch cytoplasmic membranes (sterols or lipglycans)

glycocalyx

capsules and slime layers (polysaccharide layers)

capsule

tightly attached, tight matrix of polysaccharide layer

slime layer

loosely attached polysaccharide layer, can wash off easily

purpose of capsules and slime layers

assist in attachement to purfaces, development and maintenance of biofilms, protect against phagocytosis (virulence factors), prevent dehyrdation and desiccation

fimbriae

enable organisms to stick to surfaces or form pellicles (thin sheets of cells on a liquid surface)

pili

typically longer and made of the protein PilA

adhere to host tissue and support twitching motility of some bacteria (pseudomonas)

hamus/hami

archaeal “grappling hooks”

cell inclusion functions

function as energy reserves, carbon reservoirs or have special functions

Carbon storage inclusion bodies

store glycogen or poly-B-hydroxybutyric acid (PHB - a lipid polymer)

polyphosphate granules

stores inorganic phosphate

sulfur globules

elemental sulfur oxidized to sulfate serves as an energy storage

carbonate minerals

bimineralization of barium, strontium and magnesium

magnetosomes

magnetic iron oxides, allow cells to undergo magnetotaxis: migration along the earth;s magnetic field lines

gas vesicles

conical-shaped, gas filled structures made of protein GvpA and GvpC

confer buoyancy in planktonic cells