6 Bacteria: Intro

Question 1

Phylogeny of Pacteria
Phyla and example

Answer 1

1: Proteobacteria
gram-
alpha Proteobacteria: Brucella abortus (Brucellosis)
beta Proteobacteria: Neisseria meningitis (Meningitis)
gamma Proteobacteria: Yersinia pestis (Plague)
delta Proteobacteria: Acinetobacter
epsilon Proteobacteria: Campylobacter, Helictobacter (cancerogen, gastritis)

2: Firmicutes
gram+ low gc content
Mycoplasma pneumoniae, Clostridium, Staphylococcus

3: Actinobacteria
gram+ high gc content
Corynebacterium diphteriae, TB

5: Chlamydia
obligate intracellular (Trachoma)

11: Spirochetes
gram-
Treponema pallidum (Syphilis) , Borellia

Question 2

Characterization of bacteria

Answer 2

Morphology and shape
Division (binary fission or unequal)
Spores (end, exo)
Motility (Flagellae, pili)
Cell wall (also no cell wall Mycoplasma)
metabolisms
serotyping, antibiotic resistances
Chemotaxonomy (16S rRNA, Lipodomics, …)

Question 3

Bacterial capsules
examples

Answer 3

polysacchride layers including proteins

Streptococcus pneumoniae
Bordatella pertussis
E. coli strains

Question 4

Bacterial motility
types

Answer 4

Flagellum
Monotrich (vibrio cholera)
Polytrich
Amphitrich
Lophotrich
Peritrich (Salmonella)

Hook-Filament outside of cell
Ring (P/L/MS) / Motor system inside membrane
and type 3 secretion system inside cell

Pili
Pseudomonas, Acinetobacter

Question 5

Spore formation examples

Answer 5

gram+:
Bacillus anthracis, C. tetanus, diphteriae

Question 6

Metabolic pathways (6)

How to use them for characterization?

Answer 6

Glycolysis
Glucose, NAD+P -> Pyruvate, ATP, NADH+H+

Fermentation
Glucose -> 2 ATP for Lactobacillus, Sacromyces

ß-oxidation of fatty acids
from host to generate energy

TCA (Krebs cycle)
Acetyl-Coa to produce GTP and different kind of products for other metabolic pathways

Pentose-Phosphate pathway
Glucose to generate NADPH and pentoses for nucleotide synthesis

Glyoxylate shunt pathway
Acetyl-CoA to produce succinate, bridge for TCA cycle, for intacellular bacteria

Methyl citrate pathway
production of pyruvate

You have certain end products like

Homolacti, lactic acid -> Streotpcocci
Mixed acid -> Enterobacteriacae
Butyric acid -> Clostridia
Butanediol -> Klebsiella
Propionic acid -> Propionibacterium

Question 7

Bacterial toxin function principles

Answer 7

Enzymes like Proteases, Collagenases, …

Toxins
B subunit: bind to target cell, e.g. to GM1-Ganglioside receptor for Cholera
A subunit: toxic,

Cholera: adeny cyclase in gut epithelial cells
Diphteria: to EF-2 to stop protein synthesis
Botulism: to excitation neurons to inhibit neuroransmitter
Tetanus: to inhibitory neurons to inhibit neurotransmitters

Superantigens
Interaction with ß-chain of TCR, thereby 5-25% of all T cells acitivated, toxic shock syndrome

e.g. Streptococcus (erythrogenic toxin)
, Staphylococcus (Enterotoxin A-E)

Endotoxins
LPS needs several receptor bindinf events

first LPS binding proteins, then CD14, then MD2 that is linked to TLR4, dimerization of TLR4 leads to MYD88 activation, NF-kappaB, activation

Cytolysins
Streptolysin