Lecture 3 Parasite diversity 2 prokaryotes Flashcards
What are parasitic prokaryotes?
Archaea and Bacteria
Describe Archaea parasitic prokaryotes?
- ancient, extreme habitats
- -likely no parasites
Describe Bacteria parasitic prokaryotes?
- hard to i.d – usually classify by lines/types
- –>Gram-staining diagnostic tool
Describe Gram-negative
-additional outer membrane • important as recognition signal ------>lipopolysaccharides (LPS) trigger innate immune response • sophisticated secretion systems • protection against penicillin, etc.
Describe Gram-positive
-one outer membrane
• most pathogens
• thick peptidoglycan wall
Gram-negative vs Gram- positive differences/similarities
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
Bacteria shape morphology. And specific shapes associated with cocci.
cocci (sphere), bacilli (rod-shaped), spiral (ribbon)
- diplo (2 coccus)
- Staphylo (bunch of coccus)
- Strepto ( singular line of coccus)
Describe major concern Anthrax and what parasitic bacteria it comes from
- 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
Describe major concern Pneumonia and what parasitic bacteria it comes from
- Streptococcus pneumoniae
- coccus type inhale in lungs, alveoli, left lobar lung filled with pus and inflammed
Describe major concern Tubercolosis and what parasitic bacteria it comes from
- Mycobacterium tuberculosis
- bacilli
- inhaled, highly contagious, airborne infected stages, before developed tubercolsis, quarantine them before no more TB,
Describe major concern Lyme and what parasitic bacteria it comes from
- Borrelia burgdorferi
- spiral shaped
ex. black legged tick marching northwards bc winter not cold enough to kill them, near lake erie
Describe major concern syphilis and what parasitic bacteria it comes from
- Treponema pallidum
- > spiral shaped
- > causes syphilis, sores, STD, still a problem , current antibiotic resistance
Describe major concern cholera and what parasitic bacteria it comes from
- 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
Describe major concern plague and what parasitic bacteria it comes from
- Yersinia pestis
- bacili rod shaped
- –>-plague causing bacteria black death, lives in fleas still can contract it
- trateable with anitbiotics
Describe major concern E.coli and what parasitic bacteria it comes from
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
Describe major concern ulcers and what parasitic bacteria it comes from
Helicobacter pylori
- bacilli and 4 flagellum at the end
- colonizes gastric mucos in stomach, acidic content develop ulcers
Why are bacteria important as diseases?
- 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
- Environmental reservoirs harbour bacteria:
Where does genetic variation come from? conjugation
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
Where does genetic variation come from?
• exchange of plasmids (insert DNA from DNA to another DNA)
- –> recombinant plasmid vector
- even among species!
- —>useful in research
Hmm, why should we be worried about bacterial
mixing & matching?
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
How fast do bacteria mutate?
• 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!
What does this mean for treating bacterial infections?
-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
What have we learned from studying bacterial evolution?
- Identify your pathogen & treat No appropriately antibiotics!
- Avoid mild doses
• many survivors of weak selective pressure - Complete course of treatment (selective pressure)
- Drug combos, not stronger doses • “super bacteria” from stronger
selective pressure - Avoid selective pressure
• “preventatives” ultimately harmful (antibiotics in animal feed)
