Week 6 Flashcards
Gram-Positive Bacteria: Firmicutes (Low G+C Content)
What are the phenotypic characteristics used to classify gram positive bacteria
-cell shape
-arrangement of cells
-presence of endospores
-oxygen requirements
-peptidoglycan chemistry
How does Bergeys Manual classify gram + bacteria
16S rRNA sequence comparisons
How do the peptidoglycan structures of different gram + bacterium differ
Cross-linkages between glycan chains
Endospore structure
Spore capsule, cortex, inner spore membrane which encloses the protoplasm
What acid do endospores contain
Dipicolinic acid
Class: Clostridia
Genus: Clostridium
Clostridium
-anaerobe
-food spoilage-canned food
aa
Clostridium metabolism
Produce ATP by fermenting aa under anaerobic conditions
Clostridium botulinum
Causes botulism (muscle paralysis).
Clostridium tetani
Causes tetanus
(“lockjaw”)
fart
Clostridium perfringens
Causes gas- gangrene and food poisoning.
Bacillus
aerobes/facultative anaerobes
motile rods
chemoheterotroph
Bacillus thuringiensis
-used as an insecticide
-endospore produces parasporal body
Parasporal body
-Solid protein crystal which contains a protein that can kill 100+ moth species
How does the parasporal toxin kill moths
Dissolves in their GI tract and destroys the epithelium cells -alkaline content of GIT leaches into their blood and kills them
Bacillus sphaericus
Parasporal bodies are toxic to mosquitoes
Genus: Staphylococcus
Anaerobes
-non motile
cocci
Staphylococcus metabolism
oxidase negative
catalase positive
ferment glucose anaerobically and possess teichoic acid
Staphylococci epidermidis
Causes wound infections
Staphylococci aureus
Mucous membranes of the nose, on the skin, GIT and urinary
tracts of warm-blooded animals.
Causes abscesses, wound infections, pneumonia, and food poisoning.
How to differentiate S. aureus using virulence factors
Contains coagulase enzymes that cause blood plasma to coagulate
How to differentiate S. aureus and S. epidemidis
Blood coagulation and hemolysis
Order: Lactobacillales
facultative anaerobes/aerotolerant anaerobes
non motile
non sporulating
Metabolism of Lactobacillales
no cytochromes
use substrate level phosphorylation
