Biochem/physiol Actions Mode of Action: Inhibits protein synthesis (elongation) by interfering with peptidyl tRNA translocation. Antimicrobial spectrum: Gram-negative and Gram-positive bacteria (Gonnococcus only).Mode of Resistance: Mutation in rpsE (the gene for ribosomal protein S5) prevents binding of spectinomycin. Spectinomycin is a broad spectrum antibiotic that inhibits protein synthesis (elongation) by binding to the bacterial 30S ribosomal subunit and interfering with peptidyl tRNA translocation. Resistance to spectinomycin is conferred by aminoglycoside-3′-adenyltransferase gene (aadA). It is effective against Gram-negative and Gram-positive bacteria. Mutation in rpsE (the gene for ribosomal protein S5) prevents binding of spectinomycin. Application Spectinomycin is an aminocyclitol antibiotic produced by Streptomyces spectabilis. It is used to treat acute gonorrheal urethritis and proctitis in the male and acute gonorrheal cervicitis and proctitis in the female1. It is used to mark cell layers in order to monitor cell fate during leaf development2. Spectinomycin is used as a selection marker in plant related transformation systems for plant cells that contain the marker gene Spcr. Spectinomycin is also used for amplification of low copy number plasmid carrying replicons such as Col E1, pMB1 (pBR322 and its derivatives), and p15A/rep (pACYC and its derivatives). The replication of these plasmids relies on long-lived enzymes supplied by the host. Addition of spectinomycin to the plasmid containing cells inhibits replication of the host, while the plasmids continue to replicate for 10-15 hours. The copy number of the plasmid can increase 100-fold, from 20-30 copies to 3000 copies as in the case of ColE1. Spectinomycin is used to study respiratory tract infections of cattle caused by Pasteurella multocida and Mannheimia haemolytica3. Spectinomycin dihydrochloride pentahydrate has been used to generate plants deficient for the plastid-encoded RNA polymerase (PEP) on MS-agar medium4. Protocols & Applications Antibiotic Selector for application, solubility, solution stability, working concentration, and mode of action information