3
Given below are two statements
Statement (I) : Mg?* ion is important for the preservation of structural integrity of viruses during isolation
Statement (II) : Ascorbic acid is important for the preservation of infectivity of viruses.
In light of the above statements, choose the most appropriate answer from the options given below.
EXPLANATION
Viroids, Satellite Agents & Viral Purificatio
- Biochemical Stabilization During Plant Virus Isolation:
- Statement (I) is false: Divalent cations like $ ext{Mg}^{2+}$ can induce aggregation of virions or activate endogenous plant nucleases during tissue extraction; therefore, chelating agents like EDTA (which sequester divalent cations) are routinely included in isolation buffers to prevent virion degradation.
- Statement (II) is true: Homogenizing plant tissues releases vacuolar polyphenols and polyphenol oxidases (PPO). The oxidation of polyphenols into toxic quinones inactivates virions; hence, antioxidants and reducing agents such as ascorbic acid, sodium sulfite, or $eta$-mercaptoethanol are essential to prevent oxidation and preserve virus infectivity.
- Conclusion: Statement (I) is false but Statement (II) is true (Option 4).
Correct option: (4) Statement (I) is false but Statement ({I) is true.
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