# DBT JRF 2020 — Question 92

Exam: DBT JRF 2020 · Section: B · Topic: Biotechnology · Difficulty: Hard

## Question

Nucleosides isolated from a Caribbean sponge, Cryptotethya crypta, were the basis for the synthesis of the antiviral

## Options

- **A.** Acyclovir
- **B.** Abacavir
- **C.** Avarol
- **D.** Amantadine

## Answer

Option A

## Explanation

Spongothymidine and spongouridine, isolated from the Caribbean sponge Cryptotethya crypta in the 1950s by Bergmann and Feeney, were the first marine natural products shown to have antiviral activity. They were arabinoside nucleosides (with arabinose instead of ribose), which inspired the synthetic development of arabinoside analogues. This led directly to: ara-C (cytarabine, 1959 — anticancer); ara-A (vidarabine, antiviral); and ultimately acyclovir (acycloguanosine, Zovirax, 1982 — Gertrude Elion, Nobel Prize 1988). Acyclovir is a selective inhibitor of herpes virus thymidine kinase and DNA polymerase. It is NOT related to Abacavir (HIV nucleoside RT inhibitor), Avarol (sponge sesquiterpene), or Amantadine (M2 ion channel blocker).

Source: https://mypyqbuddy.com/questions/nucleosides-isolated-from-a-caribbean-sponge-cryptotethya-crypta-6a05a8a02adafec470293274