Lecture 18 Gram Positive Bacteria

Question 1

What is the GC content of SuperPhylum Bacillota?

Answer 1

28-35%

Question 2

What are the 3 classes of firmicutes?

Answer 2

Clostirida
Bacilli
Negativicutes

Question 3

What are the key characteristics of Class Clostridia?

Answer 3

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).

Question 4

How does Genus Clostridium metabolize amino acids?

Answer 4

Clostridium is an obligate anaerobe that forms spores.

It engages in fermentative metabolism, specifically using the Stickland reaction to ferment amino acids.

Question 5

What are Clostridium tetani and where are they found?

Answer 5

Strict anaerobic spore forming bacteria
Found in soil, intestines, or feces of livestock

Question 6

What disease is associated with Clostridium tetani?

Answer 6

Tetanus
produces neurotoxins leading to muscle contractions and “lock-jaw”

Question 7

Where are Clostridium Botulinum found?

Answer 7

canned foods and soil or aquatic sediment

Question 8

What does Clostridium Botulinum cause?

Answer 8

Causes Botulism
- commonly found on surfaces of canned foods
-grow under anaerobic conditions and produce exotoxin

Question 9

What is Botox

Answer 9

Botulism toxin, prevents muscle contractions
- wrinkles, tremors, migraines etc

Question 10

What is the major impact of Clostridium perfringens on human tissues?

Answer 10

Causes gas gangrene
- infection of skeletal tissue
- replicates quickly
a-toxin breaks down muscle tissue
H2 fermentation product and CO2 cause unusual swelling

Question 11

What else does Clostridium perfringens cause?

Answer 11

Food poisoning

Question 12

Describe Class Bacilli

Answer 12

aerobic/facultative, fermenters
industrially and medically relevant.

Produce antibiotics and causative agent of anthrax.

Question 13

Name 3 types of Bacillus and their contributions to the industry

Answer 13

Antibiotic producers – bacitracin, gramicidin, polymyxin

B anthracis - causative agent for anthrax
B.thurengensis - insecticides
B.subtilis - model organism, gene regulation, cell division

Question 14

What distinguishes Order Lactobacillales?

Answer 14

non-endospore forming
non-motile
ferment sugars using homolactic or heterolactic fermentation

Question 15

What is lactobacillus known for?

Answer 15

homo and heterolactic fermentation
kimchi, yogurt, etc

normal in human gut and vaginal microbiome.

Question 16

Leuconostoc spp. known for?

Answer 16

kombucha, wine, sour dough

some produce bacteriocins to prevent listeria growth

Question 17

Staphylococcus

Answer 17

facultative anaerobes

can be pathogenic or non, depend on enzyme coagulase (if +, then pathogenic)

causes many infections; skin infections

resistant to antibiotics

Question 18

Streptococcus

Answer 18

characterized by their hemolytic patterns
a - hemolytic pneumonia
b - hemolytic strep throat

Question 19

What is hemolysis, and how is it observed in Streptococcus and Staphylococcus?

Answer 19

Hemolysis is the ability to lyse red blood cells.

Streptococcus exhibits α, β, or γ hemolysis, while Staphylococcus can be distinguished by coagulase production.

Question 20

Compound that lyses blood

Answer 20

Hemolysin

Question 21

What morphological features define Class Negativicutes?

Answer 21

Class Negativicutes have inner and outer membranes with LPS, stain Gram-negative, and are metabolically similar to Clostridia.

Question 22

How did the Gram-positive cell wall likely evolve?

Answer 22

The loss of the outer membrane led to the evolution of the Gram-positive cell wall.
G (-) cell wall traits were likely ancestral.