No abstract

Lysobactin, an antibiotic isolated from a strain of Lysobacter, is 2 to 4-fold more active than vancomycin against aerobic and anaerobic Gram-positive bacteria. Included in the spectrum of lysobactin are Staphylococci, Streptococci, corynebacteria, clostridia and various other Gram-positive anaerobic bacteria. The activity of lysobactin against aerobic and anaerobic Gram-negative bacteria is poor. Whengiven parenterally the compound was efficacious in systemic staphylococcal and streptococcal infections in mice. Similarly, when applied topically lysobactin was also curative in a staphylococcal woundinfection in mice. Somestudies on the modeof action of lysobactin are presented. Gram-positive bacteria have traditionally been susceptible to a wide variety of antimicrobial agents including the /Mactams, macrolides and tetracyclines. However, in recent years, multiply

In the presence of S-adenosylmethionine, 2-oxoglutarate, Fe2+ and a reducing agent, cell-free extracts of Streptomyces clavuligerus convert cephalosporin C and O-carbamoyldeacetylcephalosporin C into 7 alpha-methoxy derivatives. No synthesis of a 7 alpha-methoxy derivative of deacetylcephalosporin C was detected in the system used, and the 7 alpha-methoxy derivative of deacetoxycephalosporin C was produced only in relatively small amounts. It appears that the 7 alpha-methoxy group is introduced after the cephalosporin ring system has been formed and that its introduction may represent the final step in a biosynthetic pathway.

DNA topoisomerases catalyze the topological interconversions of DNA molecules which are required for several essential processes in DNA metabolism including replication, recombination, transcription, and chromosome separation at mitosis1}. They are the target for the action of potent antitumor and antibacterial agents. A bacterial type II topoisomerase, bacterial gyrase, is the target of the quinolone antibacterial agents2'3). The effectiveness of the quinolones indicates that bacterial DNA gyrase is a target for clinically useful antibacterial agents. This has stimulated interest in searches for non-quinolone DNA gyrase inhibitors. These searches have resulted in the discovery of 2 closely related antibacterial agents, cinodine and coumami-dine4j5). Cinodine has been shown to be a specific inhibitor of bacterial gyrase. We have screened