A 4-week-old laboratory mouse receives an intraperitoneal injection of live nonencapsulated Streptococcus pneumoniae mixed with heat-killed encapsulated strain. Within 48 hours, the mouse develops fever (39.2°C), tachycardia (180 bpm), and tachypnea (60 breaths/min). Blood culture yields live encapsulated S. pneumoniae; CSF shows elevated protein (180 mg/dL) without meningitis. Nonencapsulated bacteria are not recovered. Which genetic process best explains this transformation?
- A)Antigenic shift
- B)Conjugation
- C)Transduction
- D)TransformationGABARITO
- E)Transposition
Explicação
Transformation is uptake of naked DNA from the environment by a bacterium. Streptococcus pneumoniae can acquire DNA encoding capsule production in this way, converting a nonvirulent strain into a virulent encapsulated strain. Ver explicação completa e trilha adaptativa →