Hiromi B. Maruyama

NEW α-AMYLASE INHIBITOR, TRESTATINS

Trestatin complex which exhibited a potent inhibitory activity on various alpha-amylases has been isolated from the culture filtrate of Streptomyces dimorphogenes nov. sp. NR-320-OM7HB. Three major components, trestatins A, B and C, have been purified by adsorption and ion-exchange chromatography. Their spectral and chemical properties suggested that trestatins were novel basic oligosaccharide homologues each characterized by the possession of a trehalose moiety at the non-reducing end of the molecule.

Anti-mutagenic chalcones: Antagonizing the mutagenicity of benzo(a)pyrene on Salmonella typhimurium

Several chalcone derivatives; e.g. Ro 09-0204, Ro 09-0323 and Ro 09-0501 were found to reduce markedly the revertant increase of Salmonella typhimurium TA100 by benzo(a)pyrene during the incubation with S-9 Mix. The antimutagenic activity was 100 - 700 times stronger than that of L-ascorbic acid. Effect on other mutagens, the structure activity relationship and the possible mechanism of action are briefly discussed.

Comparison of the Activity of Ionophores with Other Antibacterial Agents Against Anaerobes

Representative polyethers of each group in Westleys classification and related ionophore antibiotics were examined for in vitro activity against 25 anaerobic strains. Lasalocid (X-537A) and nigericin were found to have activity comparable in potency to some leading antianaerobe antibiotics, newer cephalosporins and nitroimidazoles, with a different spectrum as revealed by a spectral comparison. A strict relationship between their antianaerobe activity and either their structural features or cation transporting properties was not apparent.

Alafosfalin, a new inhibitor of cell wall biosynthesis: in vitro activity against urinary isolates in Japan and potentiation with beta-lactams.

A new phosphonopeptide, alafosfalin, was evaluated for in vitro antibacterial activity and for synergism with beta-lactams, using 475 Japanese clinical isolates from urinary tract infections. Alafosfalin was found to be highly active against Escherichia coli and moderately active against Serratia, Klebsiella, Enterobacter, and Citrobacter, but less active against gram-positive organisms than were beta-lactams such as cephazolin or ampicillin and inactive against indole-positive Proteus, Pseudomonas, and Acinetobacter. Potentiation with the two beta-lactams (fractional inhibitory concentration less than or equal to 0.5) was found in 10 to 40% of susceptible strains in 4:1 and 1:4 combinations, and to a lesser extent in those species or genera that were insensitive to alafosfalin alone. No cross resistance was seen between alafosfalin and the beta-lactams or any other commonly used antibacterial agents tested. Effect on selected ampicillin-resistant strains, differential sensitivity to alafosfalin among resistant strains of various types, and sensitivity of alafosfalin-insensitive E. coli and Klebsiella to other antibiotics are also discussed.

Desferrioxamine B, an Inhibitor of Escherichia coli Motility, Reversing the Stimulating Effect of Cyclic Adenosine 3′,5′-Monophosphate

A substance inhibiting Escherichia coli motility was isolated by “motilometry” assay from the culture broth of Streptomyces sp. strain NR9GG8 and was found to be identical with desferrioxamine B. Its inhibitory effect was reversed by cyclic adenosine 3′,5′-monophosphate (cAMP), while the motility stimulation by cAMP was diminished by this inhibitor. Its effects on various enzymes involved in cAMP metabolism of function of cAMP were examined.

Agglutination of bacterial spheroplasts: I. Effect of concanavalin A

Concanavalin A was found to agglutinate Escherichia coli spheroplasts prepared with EDTA and lysozyme and treated with proteases, in the range of population density from 108–109 per ml. Non-treated spheroplasts were not agglutinated by this agglutinin in the above range but, when the density was higher than 1010 per ml, they showed a spontaneous agglutination regardless of concanavalin A, which was diminished by protease treatment. Concanavalin A-specific agglutination was inhibited by α-methyl-d-glycoside and other sugars, while none of the tested sugars showed any significant inhibition of the spontaneous agglutination.