Bacteriology USMLE Step 1 Practice Question
A culture of smooth Streptococcus agalactiae bacteria is grown in nutrient broth and allowed to incubate until the culture enters the decline phase of the growth curve. An extract of this process is added to a culture of rough S. agalactiae in the logarithmic phase of the growth curve and incubated for 24 hours under appropriate culture conditions. The resulting culture develops some smooth and some rough strains of S. agalactiae. Purified DNase is then added to the flask and the culture is agitated gently for 2 hours at 37.0°C (98.6°F). Afterward only rough strains of S. agalactiae are isolated from the culture. Which of the following processes would achieve the production of encapsulated S. agalactiae in this system?
Answer choices
- ALysogeny
- BConjugation
- CSite-specific recombination
- DTransduction
- ETransformationCorrect answer
- FSpontaneous mutation
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