Streptomycin sulfate is a freely soluble aminocyclitol glycoside antibiotic, that was co-discovered by Salman Waksman, Albert Schatz, and Elizabeth Bugie at the Rutgers University in 1943 and was later patented in 1948. Streptomycin is isolated from Streptomyces griseus and shows bacteriostatic activity at low concentrations and bactericidal activity at higher concentrations against mycobacteria and gram-negative bacteria. It is less active against gram-positive bacteria. Streptomycin sulfate has been found to be effective against certain β-lactam sensitive VRE or vancomycin resistant Enterococcus species; a glycopeptide antibiotic resistant "superbug”. Streptomycin sulfate is often used together with penicillin and other agents to inhibit bacterial contamination in cell culture applications. It is recommended for use in molecular biology applications at 25-50μg/mL, in cell culture applications at 100 mg/L and in embryo culture at 50 mg/L. Streptomycin is a protein synthesis inhibitor that acts by binding to the 30S ribosomal subunit at the S12 protein thereby inducing a misreading of the genetic code, inhibiting the initiation of translation of DNA, which then results in death for a susceptible bacterium. Streptomycin has also shown activity as a miRNA inhibitor, that is capable of down-regulating miR-21, a miRNA that is overexpressed in a wide variety of cancers. Streptomycin sulfate is readily water-soluble (20 mg/ml) but of low solubility in organic solvents. Streptomycin Sulfate conforms to United States Pharmacopeia standards.