Publications by authors named "Yoshikazu Shizuri"

Bacterial strains YM16-303(T) and YM16-304(T) were isolated from a sample of seashore sand using a medium with an artificial seawater base. Both isolates grew slowly on marine agar, and were found to be Gram-reaction-positive, aerobic, non-motile and rod-shaped. The cell-wall peptidoglycan contained ll-diaminopimelic acid, glycine, alanine and hydroxyglutamic acid, and the acyl type of the muramic acid was glycolyl.

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Two non-motile, rod-shaped gammaproteobacteria were isolated from marine sponges collected from the coast of Japan at Numazu. The isolates were oxidase- and catalase-positive facultative anaerobes that fermented carbohydrates. They required sodium ions for growth and were slightly halophilic, growing in the presence of 1.

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A new catechol-type siderophore, streptobactin (1), was isolated from a culture broth of the marine-derived actinomycete Streptomyces sp. YM5-799. The structure of streptobactin was determined by NMR and MS analyses and ESIMS/MS experiments to be a cyclic trimer of benarthin.

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Article Synopsis
  • Two new peptides, tumescenamides A and B, were extracted from a marine bacterium called Streptomyces tumescens YM23-260.
  • Tumescenamide A is identified as a cyclic depsipeptide made up of several amino acids with a specific 2,4-dimethylheptanoyl modification, while tumescenamide B has a different modification involving 2,4,6-trimethylnonanoyl.
  • Tumescenamide A was shown to activate gene expression associated with an insulin-degrading enzyme promoter.
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New terpenoids named gifhornenolones A (1) and B (2) were isolated from the culture broth of Verrucosispora gifhornensis YM28-088, and their structures were established as hydroxylated isopimaradiene derivatives on the basis of extensive NMR and MS spectral analyses. In addition, a known sesquiterpene compound cyperusol C (3) was isolated. The absolute configuration of 1 was determined by nuclear Overhauser effect spectroscopy (NOESY) and CD spectra as 4R, 5S, 9R, 10S, 13R, and that of 2 was determined by NOESY experiments as 3R, 4R, 5R, 9R, 10S, 13R.

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A new rifamycin antibiotic, salinisporamycin (1), has been isolated from a culture of a marine actinomycete. The producing organism was identified as Salinispora arenicola [corrected] on the basis of the 16S rRNA sequence. High-resolution FAB-MS established the molecular formula of 1 as C(33)H(43)NO(9).

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Bacterial strain YM22-133T was isolated from the sediment of an estuary and grew in media with an artificial seawater base. Strain YM22-133T was Gram-positive, aerobic, non-motile and rod shaped. The cell-wall peptidoglycan contained LL-DAP, glycine, alanine and hydroxyglutamate.

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Chalcone compounds have been widely studied for their anti-inflammatory, anti-pyretic, anti-invasive and anti-proliferative activities in various cell lines. However, their effects on the central nervous system (CNS) are still largely unexplored. We have recently developed a bioconversion system using a recombinant Escherichia coli that enables us to produce chemical compounds that are naturally rare and usually difficult to chemically synthesize.

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Strain HG667(T), isolated from surface seawater collected at the Kesennuma ferry port in Miyagi Prefecture, Japan, was found to be a Gram-positive, catalase-positive bacterium comprising irregular short rods and cocci. The diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The major menaquinone was MK-8(H4).

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A new down-regulator of the molecular chaperone GRP78, efrapeptin J, was isolated from a marine fungus, Tolypocladium sp. AMB18. The molecular formula of efrapeptin J was established as C(81)H(139)N(18)O(16)(+) by high-resolution FAB-MS.

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Article Synopsis
  • A new bacterial strain, YM6-073(T), was discovered in marine sediment from Okinawa, Japan, characterized as rod/coccoid-shaped, non-motile, and orange-colored, producing a carotenoid called myxol.
  • Phylogenetic analysis revealed that YM6-073(T) is distinct within the Flavobacteriaceae family, sharing 93.7% genetic similarity with its closest relative but showing less than 10% DNA-DNA relatedness.
  • Based on its unique phenotypic and genetic traits, YM6-073(T) has been designated as a new species, named Robiginitalea myxolifaciens sp. nov.
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A new sulfoalkylresorcinol (1) was isolated from the marine-derived fungus, Zygosporium sp. KNC52. The structure of 1 was elucidated by spectroscopic methods including MS and NMR, and the absolute stereochemistry was determined by the modified Mosher's method.

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Ascochytatin, a new spirodioxynaphthalene metabolite produced by a marine-derived fungus, was found from a screening program focused on the bacterial two-component regulatory system. The structure of ascochytatin was determined by spectroscopic methods, including NMR and MS. The relative stereochemistry was determined by an X-ray crystallographic analysis, and the absolute stereochemistry was determined by the modified Mosher's method.

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Ariakemicins A (1) and B (2), unusual linear hybrid polyketide-nonribosomal peptide antibiotics, were discovered from the fermentation extract of the marine gliding bacterium Rapidithrix sp. These metabolites were positional isomers with regard to a double bond and chromatographically inseparable, rendering the structure study on a mixture basis. The ariakemicins were composed of threonine, two omega-amino-(omega-3)-methyl carboxylic acids with diene or triene units, and delta-isovanilloylbutyric acid.

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A novel alpha-pyrone designated as alcanivorone was found in a culture broth of the marine bacterium, Alcanivorax jadensis, and its structure was determined by an analysis of 1D NMR, 2D NMR and MS data. Alcanivorone was produced by A. jadensis only when sodium pyruvate was added to the culture medium as a carbon source.

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Two new antibiotic depsipeptides, unnarmicins C (1) and A (2), were isolated from the fermentation broth of a marine bacterium, Photobacterium sp. strain MBIC06485. The structure of 1 was established by spectroscopic studies and chiral analyses of its chemical degradation/conversion products, and that of 2 by comparing its NMR, MS, and CD data with those of 1.

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Three novel hybrid polyketide-terpenoid metabolites were isolated from a Penicillium minioluteum strain. Their structures were determined by NMR spectroscopic analyses and X-ray crystallography. The proposed biosynthetic pathway including a unique retro-Claisen migration of methyl carbonate correlates the three compounds with berkeleydione and berkeleytrione.

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Novel inhibitors of fungal ATP-binding cassette transporters were obtained by screening compounds and crude extracts from marine-derived fungi and bacteria using disk diffusion assays of Saccharomyces cerevisiae strains overexpressing a variety of fungal multi-drug efflux pumps. The cyclodepsipeptides unnarmicin A and unnarmicin C were able to sensitize cells overexpressing azole drug pumps ScPdr5p, CaCdr1p, CgCdr1p, and CgPdh1p to sub-MIC concentrations of fluconazole without affecting the growth of CaCdr2p and CaMdr1p overexpressing cells. Unnarmicin A and unnarmicin C were potent inhibitors of rhodamine 6G efflux of CaCdr1p expressing cells with IC50 values of 3.

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Two novel Microbacterium species are described on the basis of phenotypic, chemotaxonomic and genotypic studies. The two strains, designated YM10-847(T) and YM11-607(T), were isolated from river sediment and unidentified hydroid, respectively, of a marine lake. The strains were Gram-positive, catalase-positive bacteria with l-ornithine as the diagnostic diamino acid of the peptidoglycan.

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A novel Janibacter species is described on the basis of phenotypic, chemotaxonomic and genotypic data. Two bacterial strains were isolated in Palau, which were both Gram-positive, catalase-positive bacteria with meso-diaminopimelic acid as the diagnostic diamino acid of the peptidoglycan. The major menaquinone was MK-8(H(4)).

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A taxonomic study was carried out to clarify the status of a Gram-negative, heterotrophic mesophile that was isolated from the marine sponge Halichondria okadai. The strain, designated HOact23(T), was a non-motile, rod-shaped (0.44-0.

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The new cyclic peptide antibiotic, urukthapelstatin A, has been isolated from a culture of Thermoactinomycetaceae bacterium Mechercharimyces asporophorigenens YM11-542. The structure of urukthapelstatin A was elucidated by NMR, MS, Marfey analysis, chiral HPLC and X-ray crystal analyses.

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Urukthapelstatin A, a novel cyclic peptide, was isolated from the cultured mycelia of marine-derived Thermoactinomycetaceae bacterium Mechercharimyces asporophorigenens YM11-542. The peptide was purified by solvent extraction, silica gel chromatography, ODS flash chromatography, and finally by preparative HPLC. Urukthapelstatin A dose-dependently inhibited the growth of human lung cancer A549 cells with an IC(50) value of 12 nM.

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