You have isolated a Gram positive soil bacterium, which you have named Gretzykri
ID: 225703 • Letter: Y
Question
You have isolated a Gram positive soil bacterium, which you have named Gretzykrinia olierensis. You hypothesize that these bacteria can undergo natural transformation. To test this hypothesis you construct a mutant in which the metA gene has been replaced with a kanamycin resistance cassette and name this mutant G. olierensis metA-km. Furthermore, G. olierensis metA-km is sensitive to the antibiotic streptomycin, while the original G. olierensis strain is not. You co-culture G. olierensis and G. olierensis metA-km in the same flask and incubate at 37oC overnight. The next day, you serially dilute the culture and plate on media containing streptomycin. Of these streptomycin resistant isolates, which of the below phenotypes would be associated with experimentally verifiable natural transformants? (1 mark for each correct choice, -1 mark for each incorrect choice) All the information given.
Select all that apply:
A. Streptomycin resistance
B. Streptomycin sensitivity
C. kanamycin resistance
D. kanamycin sensitivity
E. prototrophy
F. auxotrophy
G. pilin+
H. can never use DNA as an energy source
I. encode an outer membrane secretin for uptake of DNA
Explanation / Answer
Gretzykrinia olierensis (Wild type strain) - Strr Met+ kan-
G. olierensis metA-km (Mutant type strain) - Str- Met- Kanr
A - Wild type Strr transform to Mutant strain.
B - Not involved
C - Is used finally after this experiment to see the mutant strain has Strr Met+ Kanr
D - Not involved
E - Phototrophy not selected.
F - Auxotrophy is choosen. The Plate contain streptomycin has no met. Both Wild and Transformed strain grow.
G - Pilin+ not involved used only in G-ve bacteria.
H - No G +ve bacteria use DNA as energy source for Transformation.
I - Not involved Secretin produced only in G-ve bacteria.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.