29/12/2025
đ§Ē Griffithâs Experiment (1928)
Organism: Streptococcus pneumoniae
Animal used: Mouse (āĻāĻāĻĻā§āϰ)
Objective:āĻŦā§āϝāĻžāĻāĻā§āϰāĻŋā§āĻžāϰ āĻŽāϧā§āϝ⧠transformation āĻāĻā§ āĻāĻŋāύāĻž āϤāĻž āĻĒā§āϰāĻŽāĻžāĻŖ āĻāϰ?
đŦ Procedure (āϧāĻžāĻĒā§ āϧāĻžāĻĒā§ āϏā§āύā§āĻĻāϰāĻāĻžāĻŦā§)
Griffith Streptococcus pneumoniae-āĻāϰ āĻĻā§āĻ āϧāϰāύā§āϰ strain āĻŦā§āϝāĻŦāĻšāĻžāϰ āĻāϰā§āύâ
S strain (Smooth) â capsule āĻāĻā§ â virulent
R strain (Rough) â capsule āύā§āĻ â non-virulent
āĻāϰāĻĒāϰ āϤāĻŋāύāĻŋ āĻāĻžāϰāĻāĻŋ āĻāϞāĻžāĻĻāĻž experiment āĻāϰā§āύāĨ¤
đš Experiment 1: Live S strain
Live encapsulated (S) strain āĻāĻāĻĻā§āϰ⧠āĻĒā§āϰā§ā§āĻ āĻāϰāĻž āĻšā§
Observation:
āĻāĻāĻĻā§āϰ āĻŽāĻžāϰāĻž āϝāĻžā§
Inference:
Capsule āĻĨāĻžāĻāĻžāϰ āĻāĻžāϰāĻŖā§ S strain virulent
đš Experiment 2: Live R strain
Live non-encapsulated (R) strain āĻāĻāĻĻā§āϰ⧠āĻĒā§āϰā§ā§āĻ āĻāϰāĻž āĻšā§
Observation:
āĻāĻāĻĻā§āϰ āĻŦā§āĻāĻā§ āĻĨāĻžāĻā§
Inference:
Capsule āύāĻž āĻĨāĻžāĻāĻžā§ R strain non-virulent
đš Experiment 3: Heat-killed S strain
Heat āĻĻāĻŋā§ā§ āĻŽā§āϰ⧠āĻĢā§āϞāĻž S strain āĻāĻāĻĻā§āϰ⧠āĻĒā§āϰā§ā§āĻ āĻāϰāĻž āĻšā§
Observation:
āĻāĻāĻĻā§āϰ āĻŦā§āĻāĻā§ āĻĨāĻžāĻā§
Inference:
āĻŽā§āϤ āĻŦā§āϝāĻžāĻāĻā§āϰāĻŋā§āĻž āϰā§āĻ āϏā§āώā§āĻāĻŋ āĻāϰāϤ⧠āĻĒāĻžāϰ⧠āύāĻž
đš Experiment 4: Heat-killed S + Live R strain
Heat-killed S strain āĻāĻŦāĻ live R strain āĻāĻāϏāĻžāĻĨā§ āĻāĻāĻĻā§āϰ⧠āĻĒā§āϰā§ā§āĻ āĻāϰāĻž āĻšā§
Observation:
āĻāĻāĻĻā§āϰ āĻŽāĻžāϰāĻž āϝāĻžā§
āĻŽā§āϤ āĻāĻāĻĻā§āϰā§āϰ āĻļāϰā§āϰ āĻĨā§āĻā§ live encapsulated (S) bacteria āĻĒāĻžāĻā§āĻž āϝāĻžā§
Inference:
Heat-killed S strain āĻĨā§āĻā§ āĻā§āύ⧠āĻāĻ āϧāϰāύā§āϰ âtransforming principleâ
live R strain-āĻ āĻĒā§āϰāĻŦā§āĻļ āĻāϰ⧠āϤāĻžāĻā§ virulent S strain-āĻ āϰā§āĻĒāĻžāύā§āϤāϰāĻŋāϤ āĻāϰā§āĻā§
đ§ Conclusion
āĻāĻ experiment āĻĨā§āĻā§ āĻĒā§āϰāĻŽāĻžāĻŖāĻŋāϤ āĻšā§ āϝā§â
> āĻāĻ āĻŦā§āϝāĻžāĻāĻā§āϰāĻŋā§āĻž āĻĨā§āĻā§ āĻāϰā§āĻ āĻŦā§āϝāĻžāĻāĻā§āϰāĻŋā§āĻžā§ āĻā§āύā§āĻāĻŋāĻ āĻŦā§āĻļāĻŋāώā§āĻā§āϝ āϏā§āĻĨāĻžāύāĻžāύā§āϤāϰāĻŋāϤ āĻšāϤ⧠āĻĒāĻžāϰā§,
āϝāĻžāĻā§ Transformation āĻŦāϞāĻž āĻšā§āĨ¤
(āĻĒāϰ⧠Avery, MacLeod āĻ McCarty āĻĒā§āϰāĻŽāĻžāĻŖ āĻāϰā§āύ āϝ⧠āĻāĻ transforming principle āĻāϏāϞ⧠DNA)