Lab 4 Flashcards
Describe Rhizobia
- Gram negative
- Rod shaped
- aerobic
- Pleomorphic in adverse conditions
- Forms nodules
Describe bacteroids
Fix atmospheric nitrogen to ammonia - differentiated form
What does terminally differentiated mean (bacteroids)
Can neither divide nor revert back to nondifferentiated state.
What is leghaemoglobin
Transport oxygen to the bacteria while protecting nitrogenase (oxygen sensitive)
How do the results show antagonism
Streptococcus pyogenes (FF22 & 71-698) growth inhibited when close to the s. equi - shows that s. equi producing bacteriosins that inhibit the growth of these organisms.
Describe the results of the commensalism experiment
E. coli releases beta-lactam that degrades any antibiotic before it interferes with the cell membrane - the colonies of M. luteus near to the E. coli are able to grow but the ones further out cannot.
Describe the effect of salinity on the growth of Listonella anguillarum
It is a moderate halophile (marine environment) and grew best at 3% NaCl
Describe the effect of salinity on E. coli
Mild halophile (lower gut) and grows best at 1% NaCl
Describe the effect of salinity on S. epidermidis
Extreme halophile (skin - lots of sweat) and grew best at 8-15% NaCl
Describe the effect of temperature on B. stearothermophilus
Extremophile - grows best at 60 degrees (hot pools)
Describe the effect of Temperature on E.coli
Mesophile - grows best at 37 degrees (human body temp - very controlled)
Describe the effect of temperature on Listonella anguillarium
Psychotroph (marine environment - vry cold) - grows best at 12 degrees
Describe the effect of UV light on B. subtilis and E. coli
B.subtilis forms endospores and can survive UV exposure - tolerance to UV built due to soil environment
E.coli does not form endospores and is not tolerant to longer exposures to UV light - not exposed to it in human niche so hasn’t needed to adapt.
