Bohumil Proksa

Neosartorin, an ergochrome biosynthesized by Neosartorya fischeri

Abstract The yellow pigment, named neosartorin was isolated from the mycelium of Neosartorya fischeri. Its structure, representing an asymmetric ergochrome, was deduced from spectral data, mainly NMR experiments.

The antibiotic PSX-1 Produced byPennicilium stipitatum is identical with botryodiplodin

Antibiotic PSX-1 exhibiting antitumour activity, formerly isolated from the filtrate of a culture ofPenicillium stipitatum, was shown to be identical with botryodiplodin.

Isolation, structure elucidation and biological activity of angucycline antibiotics from an epiphytic yew streptomycete.

In the course of study of epiphytic microorganisms occurring on the surface of roots of Taxus baccata L. a new strain Streptomyces sp. AC113 was isolated. According to 16S ribosomal DNA‐based identification the new strain is 99% identical with Streptomyces flavidofuscus. This strain cultivated in an arginine glycerol medium produced three major metabolites identified as (–)‐8‐O ‐methyltetrangomycin (1), 8‐O ‐methyltetrangulol (2) and 8‐O ‐methyl‐7‐deoxo‐7‐hydroxytetrangomycin (3). The chemical structures of these angucyclines were elucidated by 1D and 2D NMR as well as by mass spectrometry. Isolated angucycline metabolites showed significant antimicrobial activity against Bacillus cereus and Listeria mocytogenes. Cytotoxic activities of compounds 1, 2 and 3 against four cell lines (B16, HT‐29 and non – tumor V79, L929) were evaluated. Compound 3 was the most potent anticancer agents with IC50 0.054 μg/ml against cell line B16. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

OR-1—a mixture of esters of glyceric acid produced byPenicillium funiculosum and its antitrypsin activity

A mixture of related metabolites (denoted OR-1) was isolated from the fermentation broth ofPenicillium funiculosum together with mitorubrinic acid. Structurally OR-1 is glyceric acid esterified with C14−C18 fatty acids. Steady-state studies revealed that OR-1 behaved like an uncompetitive trypsin inhibitor withKi 17.6 μmol/L.

2-Methylsorbic acid, an antifungal metabolite of Penicillium vermiculatum

Summary2-Methylsorbic acid (MA), (2Z,4E)-2-methyl-2,4-hexadienoic acid, is a new metabolite of Penicillium vermiculatum. Antifungal activity of this acid was higher than that of sorbic acid or the bromoderivatives bromomethylsorbic acid and bromosorbic acid. MA suppressed the growth of Talaromyces flavus and germination of its conidia. In P. vermiculatum this acid lowered production of vermiculin and inhibited proteosynthesis in Saccharomyces cerevisiae.

The formation of polyols and fatty acids during L-lactic acid fermentation by Rhizopus arrhizus

SummaryThe formation of 10 g polyols/L (glycerol, arabitol, xylitol) during L-lactic acid synthesis byRhizopus arrhizus was observed. Consumption of polyols after glucose exhaustion was discovered resulting in a subsequent rise in the lipid content of the mycelium. Lactate utilization was not detected.

Production of (-)-mitorubrinic acid byPenicillium vermiculatum

Biosynthesis of (-)-mitorubrinic acid and (-)-vermistatin byPenicillium vermiculatum strain IV/5 was stimulated by high concentration of glucose and urea as a C and N source, respectively. Effect of phosphate, trace elements and organic acids was also studied.

Regulation of biosynthesis of vermiculin and vermistatin in Penicillium vermiculatum.

Biosynthesis of vermiculin (1) and vermistatin (2) inPenicillium vermiculatum can be controlled by the carbon and nitrogen sources. Glucose and sucrose affect the levels of the two metabolites; cornsteep liquor influences the quality the biosynthesis. The concentrations of Fe3+ and Cu2+ ions also affect the biosynthesis, the effect being dependent on the type of carbon source utilized. The compounds capable of electron transport generally stimulate the production of1 and2 but do not influence the biosynthesis qualitatively.

Identity of the antibiotic ramihyphin A and cyclosporin A

The antifungal antibiotic ramihyphin A, isolated fromFusarium solani strain S-435 in 1974, was shown to be identical with cyclosporin A.

Vermilutin, a xanthone from Penicillium vermiculatum

Abstract Vermilutin, 8-formyl-1-hydroxy-6-methyl-4-(3-methylbut-1-enyl)xanthone, was isolated from the mycelium of Penicillium vermiculatum and its structure deduced from spectral data. Vermilutin and its acetate inhibited the biochemical function of in vitro grown P388 lympholeukemic cells.