Takuya Suga

Aranorosin circumvents arbekacin-resistance in MRSA by inhibiting the bifunctional enzyme AAC(6')/APH(2″).

Aranorosin circumvents arbekacin-resistance in MRSA by inhibiting the bifunctional enzyme AAC(6′)/APH(2″)

Cytosporone S with antimicrobial activity, isolated from the fungus Trichoderma sp. FKI-6626

A new microbial metabolite, cytosporone S (1) was isolated from a fermentation broth of the fungus Trichoderma sp. FKI-6626. Its chemical structure was determined primarily by NMR spectroscopy and mass spectrometry. Compound 1 showed antimicrobial activity against several Gram-positive and Gram-negative bacteria and fungi.

Coculnol, a new penicillic acid produced by a coculture of Fusarium solani FKI-6853 and Talaromyces sp. FKA-65

Coculnol, a new penicillic acid produced by a coculture of Fusarium solani FKI-6853 and Talaromyces sp. FKA-65

Identification of 2-aminobenzimidazoles as potent melanin-concentrating hormone 1-receptor (MCH1R) antagonists.

A series of 2-aminobenzimidazole-based MCH1R antagonists was identified by core replacement of the aminoquinoline lead 1. Subsequent modification of the 2- and 5-positions led to improvement in potency and intrinsic clearance. Compound 25 exhibited good plasma and brain exposure, and attenuated MCH induced food intake at 30mg/kg PO in rats.

Ascosteroside C, a new mitochondrial respiration inhibitor discovered by pesticidal screening using recombinant Saccharomyces cerevisiae

Ascosteroside C, a new mitochondrial respiration inhibitor discovered by pesticidal screening using recombinant Saccharomyces cerevisiae

Paraphaeosphaeride D and berkleasmin F, new circumventors of arbekacin resistance in MRSA, produced by Paraphaeosphaeria sp. TR-022

Two new compounds, designated paraphaeosphaeride D (1) and berkleasmin F (2) together with a previously known compound, berkleasmin A (3), isolated from a culture broth of the fungus Paraphaeosphaeria sp. TR-022, proved to be new circumventors of arbekacin (ABK) resistance in methicillin-resistant Staphylococcus aureus (MRSA). The structures of 1 and 2 were elucidated by spectroscopic analyses, including various NMR experiments. All compounds showed 10–100 times ABK circumvention activities using the paper disc method and reduced the MIC values of ABK against MRSA from 16 μg ml−1 to 4 μg ml−1 (fourfold) using the agar dilution method. These new compounds might be promising lead compounds for developing circumventors of ABK resistance in MRSA.

Trichopolyn VI: a new peptaibol insecticidal compound discovered using a recombinant Saccharomyces cerevisiae screening system

In the course of searching for insecticides from soil microorganisms, we found that a fermentation broth of the fungus, Trichoderma brevicompactum FKI-6324, produced Trichopolyn VI, a new peptaibol, which possessed significant insecticidal potential. Spectroscopic analysis showed the compound to be a new trichopolyn I derivative. This paper describes the isolation, structure elucidation and biological activity of trichopolyn VI.

Hamuramicins A and B, 22-membered macrolides, produced by an endophytic actinomycete Allostreptomyces sp. K12-0794

Two new compounds, designated as hamuramicins A (1) and B (2), were isolated from the cultured broth of an endophytic actinomycete Allostreptomyces sp. K12-0794 by silica gel column chromatography and HPLC. The structures of 1 and 2 were elucidated as 22-membered macrolide containing triene and trienone with an alkyl side chain by spectroscopic analyses including NMR experiments. Both compounds showed growth inhibition activity against Kocuria rhizophia and Xanthomonas oryzae pv. oryzae as well as human cell line toxicity.

Pyrizomicin A and B: structure and bioactivity of new thiazolyl pyridines from Lechevalieria aerocolonigenes K10-0216

Two new antibiotics, designated pyrizomicin A and B, were isolated from the cultured broth of a rare actinomycete strain, Lechevalieria aerocolonigenes K10-0216, by silica gel and HPLC purification. The chemical structures of pyrizomicin A and B were elucidated as new thiazolyl pyridine compounds by nuclear magnetic resonance and mass spectrometry. Pyrizomicin A and B both showed antimicrobial activity.

Pestynol, an Antifungal Compound Discovered Using a Saccharomyces cerevisiae 12geneΔ0HSR-iERG6-Based Assay

The multidrug-sensitive budding yeast, Saccharomyces cerevisiae 12geneΔ0HSR-iERG6, is very useful in antifungal screens. A novel compound, named pestynol (1), was discovered from a culture of the fungus Pestalotiopsis humus FKI-7473 using the multidrug-sensitive yeast. The structure of 1 was elucidated by NMR studies and modified Moshers method as (1 R,2 R,3 R,4 R)-( E)-5-(7,11-dimethyl-3-methylenedodeca-6,10-dien-1-yn-1-yl)cyclohex-5-ene-1,2,3,4-tetraol. Compound 1 showed antimicrobial activity against the Gram-positive bacteria, Klebsiella pneumoniae, and S. cerevisiae 12geneΔ0HSR-iERG6 and Mucor racemosus, but displayed only weak cytotoxicity against various human cancer cell lines. Compound 1 displayed antifungal activities against S. cerevisiae 12geneΔ0HSR-iERG6 and Mucor racemosus at 10 μg/disc.