A new antifungal naphthoquinone was synthesized from rhinacanthone in two steps by chemoselective acylation of a dialkoxide intermediate.

View full abstract

Microbial conversion of 2-methylnaphthalene to 2-methyl-1-naphthol and menadione was investigated. One hundred and twenty-eight strains among 1283 strains isolated using methylethylketone as a sole carbon source showed the activity to oxidize 2-methylnaphthalene to 2-methyl-1-naphthol and menadione of more than 0. 1 μM for 2 days. Optimization of reaction conditions using strain M502 resulted in improvement of the productivity. These products were isolated and identified by comparing with authentic samples on UV, MS, and NMR spectra. The results gave enough evidence to prove that microbial products were 2-methyl-1-naphthol and menadione.

View full abstract

Mutants with reduced membrane-bound ATPase activities were isolated from Lactococcus lactis subsp. lactis C2 as spontaneous neomycin-resistant mutants. Characteristics of the representative mutant, No. 1016-51, were compared with the parental strain in cultures using a jar fermentor with the pH controlled at various values. At pH 6. 5, the fermentation patterns, i. e., glucose consumption, growth, and lactic acid production, of both strains appeared identical. At pH 4. 5, however, the levels of growth, lactic acid production, and the amounts of lactic acid produced per cell after the culture for 24h decreased to 60, 36, and 60% of the parental strain, respectively. During the cultures at pH 6. 5, no differences were found in viabilities between both strains even after 80h. On the other hand, at pH 4. 0, the viable count of the strain No. 1016-51 in a 72-h culture decreased to less than 1% of that of the zero time, while the parental strain maintained its original viability. Therefore, it was concluded that the membrane-bound ATPase is essential for this organism to survive at low pH, probably through its function of proton pumping for maintaining cytoplasmlc pH levels.

View full abstract

A novel dimeric drimane sesquiterpenoid was isolated from the wood-rotting fungus Haploporus odorus. The structure of this compound was analyzed by spectroscopic methods and chemical transformation to a related compound.

View full abstract

A screening test was undertaken to isolate a microorganism that produced 5-oxoprolinase (without ATP-hydrolyzing). The 5-oxoprolinase (without ATP-hydrolyzing) activity (decyclization activity toward L-pyroglutamate) was found in a cell-free extract of Alcaligenes faecalis N-38A, newly isolated from a soil sample. The enzyme was purified as a homogeneous preparation. The molecular weight of the enzyme was estimated to be 47, 000. The decyclization activity was specific for L-pyroglutamate, and independent of ATP and metal ions. The reaction was a reversible one, i. e., cyclization reaction of L-glutamate to yield pyroglutamate was identified.

View full abstract