Endophytic Streptomyces sp. AC35, a producer of bioactive isoflavone aglycones and antimycins.

In this research, a microbial endophytic strain obtained from the rhizosphere of the conifer Taxus baccata and designated as Streptomyces sp. AC35 (FJ001754.1 Streptomyces, GenBank) was investigated. High 16S rDNA gene sequence similarity suggests that this strain is closely related to S. odorifer. The major fatty acid profile of intracellular lipids was also carried out to further identify this strain. Atomic force microscopy and scanning acoustic microscopy were used to image our strain. Its major excreted substances were extracted, evaluated for antimicrobial activity, purified, and identified by ultraviolet-visible spectroscopy (UV-vis), liquid chromatography-mass spectrometry (LC-MS/MS) and nuclear magnetic resonance as the bioactive isoflavone aglycones-daidzein, glycitein and genistein. Batch cultivation, performed under different pH conditions, revealed enhanced production of antimycin components when the pH was stable at 7.0. Antimycins were detected by HPLC and identified by UV-vis and LC-MS/MS combined with the multiple reaction monitoring. Our results demonstrate that Streptomyces sp. AC35 might be used as a potential source of effective, pharmaceutically active compounds.

Enniatins produced by Fusarium dimerum, an endophytic fungal strain.

Cyclohexadepsipetides enniatin B, B1 and G were isolated from the cultivation broth of Fusarium dimerum Penzig, an endophyte of Magnolia x soulangeana. Their production was about 350 mg l(-1) after 96 h of submerged cultivation in Sabouraud maltose medium. Isolated enniatins inhibited growth of selected microorganisms and activity of 12-lipoxygenase with IC50 = 0.73 mg l(-1).

Biosynthesis and biological activity of enniatins.

Enniatins are N-methylated cyclohexadepsipeptides (CHDPs), composed of three units each of N-methylated branched-chain L-amino acid and D-2-hydroxy acid arranged in an alternate fashion. These low-molecular secondary metabolites are produced by Fusarium species, typical mycotoxin producing fungi. Enniatins are known for their ionophoric, phytotoxic and anthelmintic effect, antibiotic activity and recently their potent cytotoxic activity against cancer cell lines was shown. They act also as inhibitors of drug efflux pumps. Biosynthesis, biological activity, and the structural characteristics of these microbial metabolites were summarized in this review.

OR-1--a mixture of esters of glyceric acid produced by Penicillium funiculosum and its antitrypsin activity.

A mixture of related metabolites (denoted OR-1) was isolated from the fermentation broth of Penicillium 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 with Ki 17.6 mumol/L.

Factors affecting the production of (-)-mitorubrinic acid by Penicillium funiculosum.

The optimum conditions for the production of (-)-mitorubrinic acid by mutant strain of Penicillium funiculosum CCM F-8080 were examined in shaken flask cultures. The highest production of this metabolite was achieved in a medium with glucose as the sole carbon source and (NH4)2HPO4 as the nitrogen source. The most suitable concentrations of the given sources for production of (-)-mitorubrinic acid are 80 g/l glucose and 2 g/l (NH4)2HPO4 (maximal production, 814.9 mg/l). We also observed the influence of concentration of L-phenylalanine and inorganic phosphate in culture medium on the production of (-)-mitorubrinic acid. The biological activity of mitorubrinic acid as trypsin inhibitor was determined (IC50 41.05 mumol/l).

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.

Biotransformation of benzyl thiocyanate by Streptomyces aureofaciens.

Benzyl thiocyanate, a specific stimulator of chlortetracycline biosynthesis, was transformed into dibenzyl disulphide by Streptomyces aureofaciens. The disulphide stimulated chlortetracycline production to a lesser extent than did benzyl thiocyanate.

Metabolites of Pseudevernia furfuracea (L.) Zopf. and their inhibition potential of proteolytic enzymes.

Atranorin (1), physodic acid (2), oxyphysodic acid (3) and virensic (4) acid were identified in P. furfuracea, a lichen species collected in West Tatra. According to HPLC analysis contents of these metabolites in dried material was 0.11-0.19% (1), 1.46-3.78% (2), 1.69 to 3.44% (3), 1.14-1.46% (4). Atranorin was the strongest inhibitor of trypsin as well as of the porcine pancreatic elastase.

Regulation of biosynthesis of thiolutin and aureothricin in Streptomyces kasugaensis.

L-Methionine and DL-ethionine decreased production of thiolutin and aureothricin in Streptomyces kasugaensis. In the presence of L-methionine the culture also produced 3-methylthioacrylic acid, 3-methylthiopropionic acid and 3,6-bis-(2-methylthioethyl)-2,5-dioxopiperazine. Production of the metabolites depended on the concentration of L-methionine in the medium.

Relationships between structure of 5-nitro-2-furylethylenes and their SOS-function-inducing activities in Escherichia coli.

The SOS-function-inducing activities of 36 furylethylenes were characterized in Escherichia coli K12. The induction of the SOS function was assayed by monitoring the beta-galactosidase activity in the sulA::lacZ fusion strain PQ 37. To correct for the inhibitory effects of test compounds on mRNA or protein synthesis, the level of the constitutive alkaline phosphatase was assayed in parallel. Tested furylethylenes included nine alkylesters and eleven N-alkylamides of 5-nitro-2-furylacrylic acid (NFAA) and fourteen derivatives differing not only in substituents at exocyclic double bond, but also in the position 5 of the furan ring. The induction of the SOS-function by the derivatives depends on the presence of 5-nitrofuran centre in their molecule; side chains in the position 2 modify the degree of SOS response. SOS-inducing potency of n-alkyl congeners decreases with increasing lipophilicity. Effect of derivatives with branched alkyl substituents is lower than expected from the behavior of the n-alkyl homologues. All derivatives with positive effect on SOS-function in E. coli show mutagenic activity on Salmonella typhimurium TA98 in Ames test.

New compounds with cytotoxic and antitumor effects. Part 6: Monomeric indole alkaloids of vinca minor L. and their effect on P388 cells.

Vincaminorine and vincaminoreine, the monomeric indole alkaloids, belonging to the respective quebrachamine skeletal types, and vincadifformine of the aspidospermine group were those of 15 bases examined found to exhibit a considerable inhibition effect on the P388 cells. The above-mentioned secondary metabolites inhibited the synthesis of nucleic acids and proteins. Vincadifformine, which was found to inhibit most significantly the biochemical functions of P388 cells of all monomers under study, stopped the proliferation of cells in vitro in a 50 micrograms X ml-1 concentration even after 12 h of action. The effect of vincadifformine was greater than that of vinblastine, which was evaluated under the same conditions on the P388 cells in vitro.

Cytotoxic and mutagenic in vitro effect of 7-O-epoxyalkyl derivatives of daunomycinone. Part IX.

The cytotoxic effect of (7S)- and (7R)-O-epoxyalkyl derivatives of daunomycinone on leukemia P388 cells was followed in in vitro tests and their mutagenicity was determined by means of the bacterial SOS chromotest. The biological effects of the substances were compared with those of daunomycin, carminomycin and nogalamycin. The most efficient derivative proved to be the (7S)-9-acetyl-4-methoxy 7-O-(2,3-epoxypropyl)-7,8,9,10-tetrahydro-6,9,11-trihydroxy-5, 12-naphthacenequinone 10 which inhibited the DNA and RNA synthesis and proliferation of P388 cells on the level of daunomycin or carminomycin. The cytotoxic and mutagenic action of 7-O-epoxyalkyl derivatives of daunomycinone was affected by the length of alkyl and its configuration.

Stimulation of glycolysis in Ehrlich ascites carcinoma cells with phenylhydrazonopropanedinitrile and others uncouplers of oxidative phosphorylation.

The metabolic consequences of the uncoupling effect of phenylhydrazonopropanedinitrile and others uncouplers of oxidative phosphorylation on Ehrlich ascites carcinoma (EAC) cells were investigated. Upon application of uncouplers in concentrations stimulating the respiration of EAC cells the accelerate glucose uptake and lactate production was observed. The maximal glycolysis stimulation was fourfold in relation to control at the given experimental conditions. Simultaneously the degree of conversion of glucose on lactate was increased. The acceleration of glycolysis was accompanied by stimulation of 14C-labeled adenine and valine incorporation indicating the increased rate of biosynthetic processes. The prolongation of uncoupler action time and application of their higher concentrations cause the inhibition of glycolysis and biosynthetic processes which is evoked with nonspecific effects of the compounds.