Activation of an unconventional meroterpenoid gene cluster in leads to the production of new berkeleyacetals

Fungal genomes carry many gene clusters seemingly capable of natural products biosynthesis, yet most clusters remain cryptic or down-regulated. Genome mining revealed an unconventional paraherquonin-like meroterpenoid biosynthetic gene cluster in the chromosome of . The cryptic or down-regulated pathway was activated by constitutive expression of pathway-specific regulator gene encoded within biosynthetic gene cluster. Chemical analysis of mutant -OE: extracts enabled the isolation of four berkeleyacetal congeners, in which two of them are new. On the basis of careful bioinformatic analysis of the coding enzymes in the gene cluster, the biosynthetic pathway of berkeleyacetals was proposed. These results indicate that this approach would be valuable for discovery of novel natural products and will accelerate the exploitation of prodigious natural products in filamentous fungi.

Isolation and Identification of Aspergillus Section Fumigati Strains from Arable Soil in Korea

63 strains of Aspergillus section Fumigati were isolated from 17 samples of arable soil in a central province of Korea. Based on the results of genotypic and phenotypic analyses, they were identified as Aspergillus fumigatus, A. lentulus, Neosartorya coreana, N. fennelliae, N. fischeri, N. glabra, N. hiratsukae, N. laciniosa, N. pseudofischeri, N. quadricincta, N. spinosa and N. udagawae. Among these, N. fennelliae, N. hiratsukae, N. quadricincta, and N. udagawae had not been previously recorded in Korea. The diversity of Aspergillus section Fumigati species from arable soil in Korea is also addressed.

Efeito in vitro de concentrações de metabisulfito de sódio, benzoato de sódio e sorbato de potássio sobre fungos termorresistentes / In vitro effect of concentrations of sodium metabisulphite, sodium benzoate and potassium sorbate on heat-resistant fungi

Os fungos termorresistentes dos gêneros Byssochlamys, Neosartorya e Talaromyces representam grave problema para a indústria processadora de alimentos, especialmente de frutas e hortaliças, em virtude da ocorrência de ascosporos extremamente resistentes e/ou de micotoxinas termo estáveis. Com o propósito de fornecer subsídios quanto ao uso de quantidades mais racionais de conservantes pela indústria de alimentos e, portanto, tornar seu consumo menos danoso à população, o presente estudo determinou in vitro a concentração mínima de metabissulfito de sódio, benzoato de sódio e sorbato de potássio necessária e suficiente para inibir o crescimento micelial e a germinação de ascósporos de B. fulva, N. fischeri e T.flavus em meio de cultivo acidificado (pH 3,5). Foi demonstrado que metabissulfito de sódio em baixas concentrações é tão eficiente na inibição dos fungos mencionados quanto aos demais conservantes em altas concentrações. Por comparação com os procedimentos utilizados pelas indústrias de alimentos, é possível inferir que estas podem reformular o uso de conservantes, considerando-se o tipo de matéria-prima, a temperatura de processamento, a combinação e concentração efetivamente necessária de aditivos, bem como os efeitos tóxicos desses compostos para a saúde humana.

Behaviour of Neosartorya fischeri Ascospores in pineapple juice

For heat-resistance derterminations, a Neosartorya fischeri ascospore suspension, obtained at three different conditions of temperature (20, 30 and 35ºC) and age (1, 2 and 3 months), was heat treated in pineapple juice with three different ratio conditions. The 1/k (min) values obtained were statistically analysed through the software Statisitca 6.0. At 80ºC, when there was a level change in the ratio factor from a lower (10) to a higher one (38), the thermal resistance (1/k) increased in approximately 41 per cent. The increase of the ascospore production age and temperature caused an increase on the thermal resistance approximately equal to 28 per cent and 14 per cent, respectively. Throufh the results, it could be concluded that N. fischeri presented lower thermal resistance for heating mediums with lower ratio values, or rather, the increase of the soluble solids concentration caused an increase of its thermal resistance. It was also observed that the ascospore production age and temperature increased significantly the thermal resistance of this mould in pineapple juice.