Synthesis and biological evaluation of a 4-fluoromethyl monobactam analog.

The synthesis and in vitro antibacterial activity of (+/-)(cis)-3-[2-(2-aminothiazol-4-yl)-(Z)-2-methoxyiminoacetamido]- 4-fluoromethyl-2-oxo-1-azetidinesulfonic acid, potassium salt are presented.

Mechanism of action of cinodine, a glycocinnamoylspermidine antibiotic.

The mechanism of action of cinodine, a glycocinnamoylspermidine antibiotic, was investigated. Upon addition of cinodine to growing cultures of Escherichia coli, a rapid decline in viable cell numbers was observed. Culture turbidity continued to increase for a short period before plateauing. Microscopic examination indicated that the antibiotic-treated cells continued to elongate with subsequent formation of serpentine-like structures. Radioisotopic-labeling studies of E. coli demonstrated that deoxyribonucleic acid (DNA) synthesis was immediately and irreversibly inhibited upon addition of cinodine. Ribonucleic acid synthesis was reduced after a significant delay, whereas protein synthesis remained unaffected. There was a minor degree of inhibition of incorporation of radiolabeled diaminopimelic acid into cell wall material. Cinodine likewise inhibited bacteriophage T7 DNA synthesis in infected E. coli cells. After inhibition of E. coli DNA synthesis by cinodine, intracellular DNA degradation was observed. Equilibrium dialysis studies demonstrated that the drug physically bound to DNA. These data indicate that cinodine functions as a potent irreversible inhibitor of bacterial and phage DNA synthesis.

Fluorescent Staining Technique for Nucleoid Regions of Streptosporangium albidum and Streptosporangium brasiliense.

Fluorescent staining procedures were developed for elucidating the nucleoid region in Streptosporangium albidum and Streptosporangium brasiliense. In these procedures, plugs of nutrient agar were inoculated with the microorganims and then covered with a sterile glass slide. The growing cells adhered to the surface of the slide and remained attached throughout the staining procedures. Two separate staining methods were utilized, one with bisbenzimid H33258 and the other with auramine O. Fluorescent microscopy revealed intensely stained nucleoid regions within mycelia, spores, and sporangia.

Control of extracellular slime accumulation in monokaryons and resultant dikaryons of Schizophyllum commune.

Extracellular slime accumulation, as alcohol-precipitable material was measured after eight days of growth in glucose-asparagine-salts broth in twenty-two different monokaryons and six resultant dikaryons of Schizophyllum commune. The nutritional control of slime accumulation was also examined in monokaryotic mycelium. Slime occurred after growth in sucrose, glucose, fructose and xylose, with glycerol best. Low inorganic phosphates limited both slime and mycelial growth while limiting MgSO4 decreased growth and enhanced slime. In glucose-asparagine broth, various monokaryons differed widely in slime accumulation, ranging from none (e.g., strain 19) to nearly 800 mg per 100 ml filtrate (strain 1) after eight days growth, followed by a marked decline in slime (eleven days to twenty-one days). Resultant dikaryons all showed less slime accumulation, even when established from two high slime-accumulating monokaryons. In contrast, conditions which arrested dikaryotic fruit-body morphogenesis led to increased slime accumulation.

Enzyme activities associated with arabitol and mannitol biosynthesis and catabolism in Schizophyllum commune.

Enzymes of polyol metabolism were studied in basidiospore germination of Schizophyllum commune during periods of in vivo arabitol and mannitol pool depletion (growth on glucose-asparagine) and during their subsequent synthesis (growth on acetate-NH+4). Optimal conditions for assays were established and specific activities of enzymes employing D-arabitol, D-mannitol, D-ribulose, D-fructose and D-xylulose as substrates. were traced. Inquiries into the products formed during these reactions showed that D-ribulose generated arabitol while D-fructose produced mannitol with D-xylulose giving rise to xylitol. The dehydrogenase reactions were further investigated using polyacrylamide disc gel electrophoresis. Here was revealed the existence of at least two separate enzymatic activities pertaining to the catabolism of arabitol and mannitol. Also noted were the electrophoretic patterns when D-sorbitol, ribitol, xylitol and ethanol were used as substrates