LF127 Lectures 1-8 Microbiology

microbes

tiny organisms that grow very fast and are found in every niche

organotroph

organic compounds donate e-

lithotroph

inorganic compounds donate e-

prototroph

can synthesise all organic compounds

fastidious bacteria

need specific components to grow

selective media

only some things can grown

differential media

lots of things can grow

CFU

colony forming units

surface origin hypothesis

primoridal soup theory

subsurface origin hypothesis

at hydrothermal vents on ocean floor

barophile

likes high pressure

halophile

likes very salty

microphile

needs low 02 conc

psychophile

very very low temp

mesophile

‘normal temp’

thermophile

warm/hot

hyperthermophile

very high temp

sanger sequencing

able to read and compare dna molecules

capsule

polysaccaride compounds outside the cell wall

s- layer

outer wall of proteins/ glycoprotiens

peptidoglycan

mesh like polymer that retains gram stain

lysome

antibacterial enzyme that defends hosts against bacteria

lipopolysaccarides

large and complex endotocin made up of lipid a, core polysacc and o side chain

endotoxin

producted by pathogens and can cause septic shock

porins

transmembrane proteins that make the membrane permeable

uniporter

one molecule, one way

antiporter

two molecules, one each way

symporter

two, both ways

monotrichous

single flagella

ampitricous

one flagella at each end

lopotricous

lots of flagella at each end

petritricous

lots of flagella everywhere

aerotaxis

towards oxygen

magnetotaxis

along magnetic lines

phototaxis

towards light

chemotacis

towards nutrients or away from toxins by MCP

lipopolysaccarides

large and complex endotoxin made of 3 key parts

Lipid A

two glucosamine residues. linked to a fatty acid and sometimes phosphate which stabilises

Core polysaccharides

R or P polysac, has sugar residues, side changes and negative charge

O side chain

variable, specific and rough or smooth. protects against host defences

endotoxin

produced by pathogens cell division or lysis. primes immune system. not alive but can cause septic shock.

porins

makes the outer membrane permeable and are water filled channels

periplasmic space

compounds diffuse in via poring. nutrients aquitistion ect

Flagellum

L ring, P ring, SM ring and C ring

type 1 fimbrae

well characterised and widespread

P-Pili/ f fimbrea

associated with specific diseases and have 3 variants

Type 4 pili

widely distributed in Gr- and typically longer and thin

F pilus

central 2mm channe l in many gr- bacteria

bacterial endospores

way to spread and survive in gr+ only making them very resistant to changes

the human microbiome

ecological community of communal symbiotic and pathogenic microbes that literally share our body space