Toru Okuda

Application of the random amplified polymorphic DNA using the polymerase chain reaction for efficient elimination of duplicate strains in microbial screening. II: Actinomycetes

We evaluated the random amplified polymorphic DNA (RAPD) method using Streptomyces lavendulae and Streptomyces virginiae strains to eliminate duplicate actinomycete strains in our microbial screening program. The RAPD data were compared with phenotypic characteristics, DNA relatedness, HPLC analysis of metabolites and low-frequency restriction fragment analysis by pulsed-field gel electrophoresis. These results were consistent with each other. Therefore, we conclude that RAPD is a simple, efficient, and reliable method for the selection of actinomycete strains.

Pochonicine, a polyhydroxylated pyrrolizidine alkaloid from fungus Pochonia suchlasporia var. suchlasporia TAMA 87 as a potent β-N-acetylglucosaminidase inhibitor

A new polyhydroxylated pyrrolizidine alkaloid designated as pochonicine (1) was isolated from a solid fermentation culture of the fungal strain Pochonia suchlasporia var. suchlasporia TAMA 87. The structure of 1 was determined using NMR and MS techniques as (1R*, 3S*, 5S*, 6S*, 7R*, 7a S*)-5-acetamidomethyl-3-hydroxymethyl-1,6,7-trihydroxypyrrolizidine. Pochonicine (1) showed potent inhibition against beta-N-acetylglucosaminidases (GlcNAcases) of various organisms including insects, fungi, mammals, and a plant but no inhibition against beta-glucosidase of almond, alpha-glucosidase of yeast, or chitinase of Bacillus sp. The GlcNAcase inhibitory activity of pochonicine (1) was comparable to nagstatin, a potent GlcNAcase inhibitor of natural origin.

Isolation and structure determination of TMC-151s: Novel polyketide antibiotics from Gliocladium catenulatum Gilman & Abbott TC 1280.

Abstract Six new antibiotics, TMC-151 A-F (2–7) have been isolated from organic extracts of the fermentation broth of Gliocladium catenulatum Gilman & Abbott TC 1280, isolated from a soil sample. Their structures including the absolute stereochemistries, were determined by extensive analyses of NMR and X-ray crystallography, and degradation studies. TMC-151s are novel polyketides containing D-mannopyranoside and D-mannitol or D-arabitol. These antibiotics showed moderate cytotoxicity to several tumor cell lines.

Fermentation, Isolation and Characterization of Isonitrile Antibiotics

A number of soil isolates belonging to the genus Trichoderma were found to produce isonitrins A, B, C and D and isonitrinic acids E and F, a new class of antibiotics characterized by the presence of isonitrile groups. Taxonomy of the producing organisms, fermentation, isolation and physicochemical and biological properties of isonitrins and isonitrinic acids are reported. Isonitrin A showedthe highest in vitro antimicrobial activities against gram-positive and negative bacteria and fungi.

STRUCTURES OF TMC-120A, B AND C, NOVEL ISOQUINOLINE ALKALOIDS FROM ASPERGILLUS USTUS TC 1118

Abstract Three novel isoquinoline alkaloids, TMC-120A, B and C ( 1–3 ) have been isolated from a fermentation broth of Aspergillus ustus (Bain.) Thom & Church TC 1118, a fungus isolated from rhizosphere of grass. Their structures were determined through extensive spectroscopic analyses and chemical studies. TMC-120s ( 1–3 ) are found to be the first furo[3,2- h ]isoquinoline-type alkaloids isolated from natural sources.

Quinolactacide, a New Quinolone Insecticide from Penicillium citrinum Thom F 1539

By a screening program searching for new pesticides from fungal sources, an insecticidal compound was isolated from Penicillium citrinum F 1539. The compound, named quinolactacide, was novel and showed 88% mortality against green peach aphids (Myzus persicae) at 250 ppm. Its structure was determined by spectroscopic techniques.

Isolation and biosynthesis of preussin B, a pyrrolidine alkaloid from Simplicillium lanosoniveum.

A new pyrrolidine alkaloid, preussin B (1), was isolated from the culture extract of the fungus Simplicillium lanosoniveum TAMA 173 along with the known congener preussin (2). The structure and absolute configuration of 1 were determined by spectroscopic analysis and spectral comparison with 2. Feeding experiments with 13C-labeled precursors revealed that the pyrrolidine ring of 1 was assembled from acetate and l-phenylalanine by a PKS-NRPS hybrid biosynthetic pathway.

Marianins A and B, prenylated phenylpropanoids from Mariannaea camptospora

Marianins A (1) and B (2), two new prenylated phenylpropanoids, were isolated from the culture extract of the fungus Mariannaea camptospora. Structures of marianins were elucidated by interpretation of NMR and other spectroscopic data. 1 is a 5-methylcoumarin bearing two prenyloxy groups, while 2 is an orcinol derivative substituted with a 3,3-dimethyl-4-pentenoyl chain. 2 is possibly derived from 1 through a Claisen rearrangement of the prenyl group, followed by lactone hydrolysis and decarboxylation. These compounds showed weak antibacterial activity against Micrococcus luteus.

Selective isolation and study on the global distribution of the genus Planobispora in soils

Planobispora strains, including the type strain, produced abundant sporangia on humic acid-vitamin gellan gum medium when more than 50 colonies grew on a plate. However, these strains did not produce sporangia on the aerial mycelium, a diagnostic characteristic of this genus, when fewer than 20 colonies grew on a plate. Trace salts, such as FeSO4 x 7H2O, MnCl2 x 4H2O, ZnSO4 x 7H2O, and NiSO4 x 6H2O, stimulated sporangium formation of Planobispora strains. Better sporangium formation of Planobispora strains was observed on the humic acid-trace salts gellan gum medium at pH 9.0 than at neutral pH. Moreover, an alkaline medium repressed the growth of three out of six Streptomyces strains so that this condition was effective for selective isolation of Planobispora strains. An alkaline flooding solution of skim milk, five antimicrobial agents, and dry heat treatment at 90 degrees C for 60 min were effective for selective isolation. Using these techniques, we examined the distribution of Planobispora strains by using 1467 soil samples collected from Japan and other parts of the world. One hundred and nineteen Planobispora strains were isolated from 51 soil samples (3.5% of the samples tested) that were collected in Ecuador, Egypt, French Guiana, India, and Madagascar. Planobispora strains were recovered only in tropical and subtropical soils. To our knowledge, this is the first record that Planobispora strains have been isolated from locations other than Venezuela, Namibia, or South Africa.

A new species of Pseudocercospora and new record of Bartheletia paradoxa on leaves of Ginkgo biloba

A new species of Pseudocercospora is described on lesions restricted to the leaf margins of living leaves of Ginkgo biloba in Taiwan. The lesions were also colonized by the hyphomycete Scolecobasidium humicola. Telia of the basidiomycete Bartheletia paradoxa are first recorded from Japan. These three species are presumed to be saprobionts in the primary stage of litter decomposition or as weak pathogens. A short survey of fungi recorded from ginkgo with focus on ginkgo leaves is provided.