diversity and biology of bacteria p1 L7 Flashcards
TUBERCULOSIS
caused by mycobacterium tuberculosis
affecting lungs
one of top 10 causes of death but is highly treatable and preventable
multidrug resistant TB is a major healtth crisis
bacterial meningitis
major healthcare challenge, high in subtropical Africa
high fatality with no treatment
targets brains
food borne illness caused by
salmonella
e.coli
clostridium perfringens
importance of microbiome
develops intestinal immune system
homeostasis
prevents colonisation and infection of pathogens - as competition
nucleoid
DS DNA
circular chromosomes
supercoiled
cell membrane
lipid bilayer with no cholesterol
anchor for proteins
acts as osmotic barrier
transport of solutes
synthesis of lipids and cell wall polymers
helps with cell shape
detects environmental cues
cell wall
rigid layer with peptidoglycan
resists osmotic pressure
determines cell shape
signal to innate system
acid-fast cell envelope
large amounts of wax - mycotic acids - long branched and complex fatty acids
hydrophobic layer
reduces rate of nutrient uptake
only some have it
peptidoglycan
complex sugar polymer
give mechanical stress
resist osmotic pressure in cytoplasm
role in bacterial repliaction
target of antibiotics
thick = gram +Ve
thin = gram -ve
peptidoglycan inflammatory response trigger
triggers response in immune cell recognition via NOD1 NOD2, activating production of pro-inflammatory cytokines like IL-8
lysozyme
antimicrobial protein aiding host defence
gram +ve bacteria cell wall has….
lipoteichic acids
teichoic acid - outer part of peptidoglycan, promotes biofilms and adherence to host cells, and inflammatory response
- provides rigidity, major surface antigen
gram -ve bacteria cell wall
more complex than +Ve
2 membranes and thin peptidoglycan
LPS on outer membrane
periplasmic space
transport systems from ion, protein, sugars etc, hydrolytic enzymes and virulence factors
LPS
fatty acid that is a highly strain specific antigen
essential for bacterial viability
hydrophilic so repels hydrophobic molecules that could damage membrane (antibiotics)
LPS structures used to classify bacteria
target for antibiotics
How do some bacteria modify their cell wall peptidoglycan to enhance pathogenicity?
c) By modifying the sugar backbone and amino acid side chains
Mycolic acids in the acid-fast cell envelope contribute to which property of Mycobacterium species?
Impenetrability to many harsh chemicals
Which part of the lipopolysaccharide (LPS) molecule is primarily responsible for causing fever in the host?
Lipid A
Porins in the outer membrane of Gram-negative bacteria allow for the passage of which type of molecules?
Small hydrophilic molecules (MW < 700 da)
The O antigen of LPS is particularly useful for which purpose?
b) Classifying bacteria into serotypes
