Lecture 18 Gram Positive Bacteria Flashcards
What is the GC content of SuperPhylum Bacillota?
28-35%
What are the 3 classes of firmicutes?
Clostirida
Bacilli
Negativicutes
What are the key characteristics of Class Clostridia?
Class Clostridia includes strict anaerobes with fermentative or respiratory metabolism. They are spore-forming and are involved in various industrial (biobutanol), environmental (fermenters), and medical processes (exotoxin).
How does Genus Clostridium metabolize amino acids?
Clostridium is an obligate anaerobe that forms spores.
It engages in fermentative metabolism, specifically using the Stickland reaction to ferment amino acids.
What are Clostridium tetani and where are they found?
Strict anaerobic spore forming bacteria
Found in soil, intestines, or feces of livestock
What disease is associated with Clostridium tetani?
Tetanus
produces neurotoxins leading to muscle contractions and “lock-jaw”
Where are Clostridium Botulinum found?
canned foods and soil or aquatic sediment
What does Clostridium Botulinum cause?
Causes Botulism
- commonly found on surfaces of canned foods
-grow under anaerobic conditions and produce exotoxin
What is Botox
Botulism toxin, prevents muscle contractions
- wrinkles, tremors, migraines etc
What is the major impact of Clostridium perfringens on human tissues?
Causes gas gangrene
- infection of skeletal tissue
- replicates quickly
a-toxin breaks down muscle tissue
H2 fermentation product and CO2 cause unusual swelling
What else does Clostridium perfringens cause?
Food poisoning
Describe Class Bacilli
aerobic/facultative, fermenters
industrially and medically relevant.
Produce antibiotics and causative agent of anthrax.
Name 3 types of Bacillus and their contributions to the industry
Antibiotic producers – bacitracin, gramicidin, polymyxin
B anthracis - causative agent for anthrax
B.thurengensis - insecticides
B.subtilis - model organism, gene regulation, cell division
What distinguishes Order Lactobacillales?
non-endospore forming
non-motile
ferment sugars using homolactic or heterolactic fermentation
What is lactobacillus known for?
homo and heterolactic fermentation
kimchi, yogurt, etc
normal in human gut and vaginal microbiome.
Leuconostoc spp. known for?
kombucha, wine, sour dough
some produce bacteriocins to prevent listeria growth
Staphylococcus
facultative anaerobes
can be pathogenic or non, depend on enzyme coagulase (if +, then pathogenic)
causes many infections; skin infections
resistant to antibiotics
Streptococcus
characterized by their hemolytic patterns
a - hemolytic pneumonia
b - hemolytic strep throat
What is hemolysis, and how is it observed in Streptococcus and Staphylococcus?
Hemolysis is the ability to lyse red blood cells.
Streptococcus exhibits α, β, or γ hemolysis, while Staphylococcus can be distinguished by coagulase production.
Compound that lyses blood
Hemolysin
What morphological features define Class Negativicutes?
Class Negativicutes have inner and outer membranes with LPS, stain Gram-negative, and are metabolically similar to Clostridia.
How did the Gram-positive cell wall likely evolve?
The loss of the outer membrane led to the evolution of the Gram-positive cell wall.
G (-) cell wall traits were likely ancestral.
