Question

Streptomycin is obtained from.
A. Streptomyces griseus
B. Streptomyces aureofaciens
C. Streptomyces venezuelae
D. Streptomyces rimosus.

Answer 1

Hint: Streptomycin is an antibiotic produced by gram negative bacteria to treat several diseases. Number of antibiotics are produced by various Streptomyces species, like tetracycline, chloramphenicol and tetracycline kind of antibiotics.

Complete answer:
Streptomycin is the aminoglycoside antibiotic which is obtained from Streptomyces griseus, which is commonly found in soil and used to treat a number of bacterial diseases like tuberculosis in combination with other medicine. It is first isolated by Albert Schatz PhD scholar. This antibiotic works as binding to 30S bacterial ribosomal subunits, which causes the misreading of t- RNA which lead to inability to synthesis of protein that are necessary for growth.
b. Streptomyces aureofaciens produce tetracycline antibiotics. It is an oral antibiotic and it acts by inhibition of binding aminoacyl-tRNA, mainly to 70S ribosomes. This inhibition leads to the effect of tetracyclines, showing bacteriostatic effect. It was first isolated by Benjamin Duggar in 1948.
c. Streptomyces venezuelae :- it is also gram negative soil dwelling bacterium, it is filamentous in nature. It produces chloramphenicol antibiotic, it is the first antibiotic produced on large scale synthetically which derived from Streptomyces venezuelae some other secondary metabolites also produce this bacterium is jadomycin and pikromycin. The chloramphenicol is a broad spectrum antibiotic which shows bacteriostatic effect which inhibits the protein synthesis of bacteria by reverse binding of peptidyl transferase of 50S ribosomal subunit.
d. Streptomyces rimosus :- It is an antibiotic producing gram negative bacterium species belonging to genus Streptomyces, it is produced terramycin antibiotic which inhibits the growth of bacteria.

So, the correct answer is option B.

Note: Streptomycin is only antibiotic which is produce by Streptomyces griseus and Streptomyces ramosus produce terramycin while Streptomyces rimosus produce oxytetracycline, all of them work on different range of spectrum.