Question

Streptomycin is the oldest aminoglycoside antibiotic obtained from:

• A. Streptomyces kanamyceticus
• B. Streptomyces griseus
• C. Streptomyces tenebrarius
• D. Micromonospora inyoensis

Hint:

To remember this:
- Streptomycin $\rightarrow$ Streptomyces griseus.
- Kanamycin $\rightarrow$ Streptomyces kanamyceticus.
- This suffix spelling rule ("-mycin" vs "-micin") is a helpful indicator of the original biological source.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Aminoglycosides are bactericidal antibiotics that inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit.
The suffix "-mycin" designates antibiotics obtained from the genus *Streptomyces*, while "-micin" designates those derived from the genus *Micromonospora*.

Step 2: Detailed Explanation:
Let us match each bacterial species with the specific aminoglycoside it produces:
- Streptomyces kanamyceticus: Produces Kanamycin.
- Streptomyces griseus: Produces Streptomycin, which was the first aminoglycoside discovered (in 1943 by Albert Schatz and Selman Waksman) and the first effective antibiotic treatment for tuberculosis.
- Streptomyces tenebrarius: Produces Tobramycin.
- Micromonospora inyoensis: Produces Sisomicin.

Step 3: Final Answer:
Thus, the oldest aminoglycoside, Streptomycin, is obtained from Streptomyces griseus.