3. microbial physiology Flashcards
1
Q
myxomycota, plasmodial slime moulds
A
- acellular multinucleate plasmodium advances by cytoplasmic streaming
- from ATP/actinomyosin action with actin filaments squeezing cytoplasm forward in the direction of movement
- can differentiate into sporangia, release flagellate swarmers which then may differentiate into myxoamoebae
2
Q
observing cytoplasmic streaming
A
- Physarum polycephalum
- under 4x microscope lens
- streaming in both directions
- one direction to advance, the other to transport nutrients around
- if advancing it should stream in forward direction longest
3
Q
calibrating a microscope
A
- 1mm calibration slide, 1,000 micrometers
- 100 eyepiece units
- line them up to figure out how many micrometers each eyepiece unit is for each magnification
- should be proportionate e.g x4, 1eu = 25 micrometers, x40, 1eu = 2.5 micrometers
4
Q
finding CFU/ml from a serial dilution
A
- CFU/ml = colony forming units per ml, determines viable cells per ml of original suspension
- count colonies on a plate exhibiting 3-300 colonies e.g. 10-4 dilution was 300 colonies
- times count by dilution e.g. 300cfu*10,000dil
- divide colony count by amount of solution plated e.g. 3000000/0.1ml
= 3 x10^7 CFU/ml
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