Lecture 3 Parasite diversity 2 prokaryotes

Question 1

What are parasitic prokaryotes?

Answer 1

Archaea and Bacteria

Question 2

Describe Archaea parasitic prokaryotes?

Answer 2

• ancient, extreme habitats

- -likely no parasites

Question 3

Describe Bacteria parasitic prokaryotes?

Answer 3

• hard to i.d – usually classify by lines/types

- –>Gram-staining diagnostic tool

Question 4

Describe Gram-negative

Answer 4

-additional outer membrane 
• important as recognition signal
------>lipopolysaccharides (LPS) trigger innate immune
response
• sophisticated secretion systems
• protection against penicillin, etc.

Question 5

Describe Gram-positive

Answer 5

-one outer membrane
• most pathogens
• thick peptidoglycan wall

Question 6

Gram-negative vs Gram- positive differences/similarities

Answer 6

Stain colour:
Neg: pink
Pos: purple

# Outer wall:
Neg: 2 -> peptidoglycan & outer membrane layer with LPS
Pos: 1 -> peptidoglycan

size of peptidoglycan:
Neg: thin
Pos: thick

LPS immune response to invaders?
Neg: Yes
Pos: No

Question 7

Bacteria shape morphology. And specific shapes associated with cocci.

Answer 7

cocci (sphere), bacilli (rod-shaped), spiral (ribbon)

• diplo (2 coccus)
• Staphylo (bunch of coccus)
• Strepto ( singular line of coccus)

Question 8

Describe major concern Anthrax and what parasitic bacteria it comes from

Answer 8

• Bacillus anthracis
• > rod type of bacterium, cause sores through cuts, if you inhale spores get into lungs need to get appropriate antibiotic treatment
• can be airborne
• anthrax spores sneak into lungs -> white blood cells attack spores in lungs -> growing spores in lymph nodes. Vaccinated are immune here -> striking : toxin spread via lymphatic system, causes internal bleeding/damage to major organs. if circulated, antibiotics can’t do anything

Question 9

Describe major concern Pneumonia and what parasitic bacteria it comes from

Answer 9

• Streptococcus pneumoniae

- coccus type inhale in lungs, alveoli, left lobar lung filled with pus and inflammed

Question 10

Describe major concern Tubercolosis and what parasitic bacteria it comes from

Answer 10

• Mycobacterium tuberculosis
• bacilli
• inhaled, highly contagious, airborne infected stages, before developed tubercolsis, quarantine them before no more TB,

Question 11

Describe major concern Lyme and what parasitic bacteria it comes from

Answer 11

• Borrelia burgdorferi
• spiral shaped
  ex. black legged tick marching northwards bc winter not cold enough to kill them, near lake erie

Question 12

Describe major concern syphilis and what parasitic bacteria it comes from

Answer 12

• Treponema pallidum
• > spiral shaped
• > causes syphilis, sores, STD, still a problem , current antibiotic resistance

Question 13

Describe major concern cholera and what parasitic bacteria it comes from

Answer 13

• Vibrio cholerae
• –> bacili with flagellum attached
• –>cholera disease, water borne bacterium, water supply is contaminated, diarrhea, vomiting, die from dehydration and electrolytes, very opportunistic when water supply is damamged, ex, HAITI ppl died because of this

Question 14

Describe major concern plague and what parasitic bacteria it comes from

Answer 14

• Yersinia pestis
• bacili rod shaped
• –>-plague causing bacteria black death, lives in fleas still can contract it
• trateable with anitbiotics

Question 15

Describe major concern E.coli and what parasitic bacteria it comes from

Answer 15

Escherichia coli

• fuzzy bacili with flagellum attached all over
• not all strains are pathogenic bc of contamination of water, bags of spinach, salad spread easily

Question 16

Describe major concern ulcers and what parasitic bacteria it comes from

Answer 16

Helicobacter pylori

• bacilli and 4 flagellum at the end
• colonizes gastric mucos in stomach, acidic content develop ulcers

Question 17

Why are bacteria important as diseases?

Answer 17

• easily transmission
  –> direct
  -parasitic hosts & vectors
  • environmental persistence
  -resistant stages, dormant
  
  • Environmental reservoirs harbour bacteria:
    -surface biofilms, cyanobacteria, copepods, chromoid egg massess
    • rapid evolution- conjugation

Question 18

Where does genetic variation come from? conjugation

Answer 18

conjugation; asexually reprodruce, exchange through conjugation through the same strain, also to distantly related strains explains why it takes a huge leap to become pathogenic, now have to worry about diff strains of bacteria

Question 19

Where does genetic variation come from?

Answer 19

• exchange of plasmids (insert DNA from DNA to another DNA)

• –> recombinant plasmid vector
• even among species!
• —>useful in research

Question 20

Hmm, why should we be worried about bacterial

mixing & matching?

Answer 20

worried because recombination
-very rapid population growth
—–> high intensity
——>Log or exponential growth phase , replication high exchanging genetic material mutant strains popping
• start with 1 bacterium colony of 1000 after 10
generations
• 2.8 million nucleotide base pairs

Question 21

How fast do bacteria mutate?

Answer 21

• assume 10 exp -10 mutations/nucleotide base

• –> ~ 300 mutations in population within 10 hours
• 30 hours for single bacterium to grow into a population in which every single base pair in the genome will have mutated not once, but 30 times!

Question 22

What does this mean for treating bacterial infections?

Answer 22

-strategies against 1 type of parasite can work for others
Which antibiotic cycling is most effective?
this most effective, not allowing pop enough to evolve resistance, chance of 1 variant to three diff kind of drugs, keep down pop growth

Question 23

What have we learned from studying bacterial evolution?

Answer 23

1. Identify your pathogen & treat No appropriately antibiotics!
2. Avoid mild doses
   • many survivors of weak selective pressure
3. Complete course of treatment (selective pressure)
4. Drug combos, not stronger doses • “super bacteria” from stronger
   selective pressure
5. Avoid selective pressure
   • “preventatives” ultimately harmful (antibiotics in animal feed)