chapter 11

binary fission

1. cell replicates its DNA

2. cytoplasmic membrane elongates, separating DNA molecules

3. cross wall forms; membrane invaginates

4. cross wall forms completely

5. daughter cells separate

snapping division

a newer, inner cell wall grows as the cell gets bigger then the older cell wall snaps

• found mainly in Corynebacteria

• gives v shape

spores

reproductive cells that can separate and develop into a clone of the parent cell (type of budding)

• ex.) Actinomycetes

endospores

a mechanism that bacteria use to survive conditions that would normally kill an active cell

• ONLY Bacillus and Clostridium produce

nucleic acid sequence content

• useful for gram+ bacteria

• can vary between 20-80% in prokaryotes

• the higher the %, the more closely related groups are

G + C equation

(G + C) / (A + T + G + C) x 100

G + C < 50%

firmicutes

• low content

G + C > 50%

actinobacteria

• high content

clostridium

rod-shaped, obligate anaerobes that form endospores

• vegetative cells produce toxins

important clostridium

• c. tetani

• c perfrigens

• c. botulinum

• c. difficile

c. tetani

causes tetanus which is fatal if untreated (affects neuromuscular transmission)

• vaccine = TDAP & DTAP (tetanus, whooping cough, and diptheria)

c. perfrigens

causes gas gangrene

• cytotoxic: cells and tissues die

• seen in poorly managed diabetes, may put affected limb in hyperbaric chamber

c. botulinum

causes botulism and is used in botox

• botulism - fatal, affects neuromuscular transmitters

• botox - VERY diluted, paralyzes muscles for a little bit

c. diff

causes severe diarrhea

• resistant to many antibiotics

bacillus

• endospore forming aerobes and facultative anaerobes

• species are common in soil

• b. anthracis, b. cereus, and b. subtilis

b. anthracis

causes anthrax by producing toxins that kill surrounding tissues

• used in bioterrorism attack in 2001

• can be cutaneous and inhalation

• untreated ~20% and 100% fatal

b. cereus

causes food poisoning

• often at buffets where things are kept warm for a long time

enterococcus

• normally found in GI tract

• can be asymptomatic carrier

• cause HAI UTIs in immcompromised patients

• most important are e. faecalis and e. faecium

vancomyocin

one of the most powerful gram+ antibiotics

listeria monocytogenes

facultative anaerobes that can contaminate milk and meat

• causes listeriosis

• able to reproduce when refrigerated and evade host immune response

• enters the body through contaminated food or drink (often contaminated equipment)

• listeriolysin O is a toxin produced by bacteria and it keeps it from being digested by the hosts macrophages

• can cause flu-like illness, meningitis and can be transmitted to the fetus and cause misscarriage or stillbirth

listeriosis

1. listeria enters the body (usually through contaminated drink or food)

2. listeria triggers its own phagocytosis by host cell typically in the gallbladder (bile!)

3.