AM-2282, a new alkaloid has been isolated from cultures of Streptomyces sp. AM-2282 by solvent extraction and silica gel chromatography. The compound exhibits a strong absorption maximum at 292 nm and shows antimicrobial activity against fungi and yeast. The LD50 of its hydrochloride (i.p. in mice) is 6.6 mg/kg. The molecular formula of AM-2282 has been determined as C28H26N4O3. The producing strain, AM-2282 was classified as a new species and the name, Streptomyces staurosporeus AWAYA, TAKAHASHI and OMURA, nov. sp. is proposed.
A basic compound with empirical formula C12H16N2O5 was isolated from Bacillus cereus 102804 fermentations of a soybean meal - glucose medium. The inhibitory activity of compound 102804 on growth of Gram-positive and Gram-negative bacteria growing in a chemically defined medium was reversed by vitamin B12, by L-methionine, and by D-methionine. It has no inhibitory activity for Escherichia coli (Davis 113-3) when grown in media containing L-methionine. The biosynthesis of 102804 coincides with the sporulation of the B. cereus, and the compound is not produced in the absence of sporulation.
Papulacandin, a new antibiotic complex, active against Candida albicans and several other yeasts, was isolated from a strain of Papularia sphaerosperma. The fermentation, isolation, physico-chemical properties and biological activity of the five structurally related papulacandins A, B, C, D and E are reported. Papulacandin B, the main component, was assigned the formula of C47H64O17.
Aculeacin A, a new antifungal antibiotic was isolated from the mycelial cake of Aspergillus aculeatus M-4214. The antibiotic is a white amorphous powder soluble in lower alcohols and hardly soluble in other organic solvents or water. Aculeacin A gave palmitic acid and five ninhydrin-positive products including threonine, hydroxyproline upon acid hydrolysis. The antibiotic showed a potent activity against molds and yeasts, but exhibited no antibacterial activity. Aculeacin A has relatively low toxicity in mice.
Six new antibiotics were isolated as the minor components related to aculeacin A from the culture broth of Aspergillus aculeatus M-4214 and named as aculeacins B, C, D, E, F and G. Their physico-chemical properties were analogous to those of aculeacin A and they showed significant activity against fungi. All of the minor components liberated palmitic acid on alkaline hydrolysis. Amino acid analysis showed that threonine and hydroxyproline are common constituents of aculeacins.
The mode of action of a new antifungal antibiotic, aculeacin A, was studied with the cells of Saccharomyces cerevisiae. In the presence of aculeacin A, the distinct decrease of viable cells was observed. The most of cells treated with aculeacin A lysed with releasing intracellular substances at the tips of their buds. This lysis was considered to be due to the inhibition of cell wall synthesis, because the incorporation of glucose into the cell wall glucan was significantly reduced. Aculeacin A also had a weak activity to burst the protoplasts of S. cerevisiae at a relatively high concentration.
The two antibiotics ASN-136 and monoketo-organomycin (MKOM) showed very close similarities in their UV, IR spectra and elemental analysis to those of tuberactinomycin and yazumycin respectively. Further chemical and enzymic studies revealed the novelty of the two former antibiotics. Partial enzymic hydrolysis of MKOM yielded a hydrolytic product of more potent inhibitory action compared with the parent antibiotic. Having cystine as the N-terminus and taurine as the C-terminus in its molecule, this enzymic degradation product was designated cystaurimycin. Performic acid oxidation of MKOM and of cystaurimycin improved their growth inhibitory effects on the test organisms used.
The effect of amphotericin B (AB) and amphotericin B methyl ester (AME) on viability and DNA synthesis in three insect cell lines, Trichoplusia ni (Tn), Carpocapsa pomonella 169 (Cp) and Aedes aegypti (Aa), has been evaluated. In all cases AME was less toxic than AB and inhibited DNA synthesis to a lesser degree than AB. However, the three cell lines differed in their response to the two polyene macrolide antibiotic preparations. Tn and Aa cell responded in a similar manner when exposed to either AME or AB, whereas Cp cells were more sensitive to both antibiotics than Tn or Aa cells.
The in vitro antibacterial activity of two agents relatively resistant to beta-lactamases, BL-S786 and cefoxitin, was tested against 123 recent different clinical isolates of cephalothin-resistant Enterobacteriaceae. BL-S786 showed considerable activity against Escherichia coli and lesser activity against Klebsiella pneumoniae with, respectively, 68% and 41% inhibited at 32 μg/ml. Cefoxitin showed more activity in vitro against E. coli, K. pneumoniae, Serratia marcescens and Providencia stuartii. Cefoxitin appears to be a more promising agent for treating infections caused by cephalothin-resistant Enterobacteriaceae.