Gentamicin is a broad-spectrum aminoglycoside antibiotic effective against Gram-negative and Gram-positive bacteria. It also inhibits the growth of various strains of mycoplasma in tissue culture. Gentamicin inhibits protein synthesis by binding to 30S ribosomal subunit leading to errors in mRNA translation, and thus causing cell death. It is widely used as a selection agent (gentamicin-resistance gene) in molecular biology and cell culture applications.