Lipoxygenase Inhibitors Nordihydroguaiaretic Acid and Fungus Lecanicillum lecanii Extract Induce Death of Lymphoid Leukemia Cells.

We studied the effect of lipoxygenase inhibitors nordihydroguaiaretic acid (NDGA) and fungus Lecanicillum lecanii extract on lymphatic leukemia P388 cells. The cells grown in the abdominal cavity of DBA2 mice for 7 days were transferred into a nutrient medium. The effect of lipoxygenase inhibitors was evaluated by changes in cell number, trypan blue staining, nucleus damage, and changes in cell distribution by DNA content after 22-h incubation. NDGA and fungus extract induced apoptotic death of lymphatic leukemia cells, which was seen from nucleus damage and reduced DNA content in cells. IC50 for NDGA and fungus extract was 0.66 and 5.5 µg/ml, respectively.

[Screening of Organisms Producing Inhibitors of 15-Lipoxygenase Among Micromycetes.]

The effects of extracts from the mycelium of Lecanicilium lecaniiNo.169, Beauveria fellina No.7 and Beauveria bassianaNo.15 on the activity of 15-lpoxygenase (15-LO) recovered from rat reticulocytes was investigated. The activity of 15-LO was determined by oxidation of linolic acid. The extract from the mycelium of the fungal complex was shown to inhibit 15-LO (IC50 of 12 mcg/ml). The inhibitory effect of the combined extract on 15-LO was due to the substances recovered from Lecanicilium lecanii No.169. The extract fractions responsible for the activity were determined and the compounds containing the fractions were identified. They proved to be 10 - 4-hydroxybenzoic acid and 4-hydroxybenzyl alcohol and genistein, a flavonoid from fraction 11. The possible role of the inhibitory effect of the compounds on 15-LO in the antiatherosclerotic activity of the fungal extract is discussed.

[Change of Tumor Cell Multiple Drug Resistance Inhibitory Activity of Oligomycins in Complexes with Lithium and Zinc].

Oligomycins and their complexes with lithium and zinc were shown to be less active vs. cyclosporin A in inhibition of transport proteins responsible for multiple drug resistance of lymphoid leukosis P388VR cells, while certain oligomycin complexes were tens or hundreds times more active than cyclosporin A by inhibition of transport proteins in another type of tumor cells, i.e. human larynx cancer Hep-2, that makes possible the use of the oligomycins complexes with lithium and zinc for inhibition of multiple drug resistance of certain tumor types.

[Determination of oligomycins hydrophobicity parameters].

The parameters of hydrophobicity of five oligomycins, i. e. A, B, C, F and SC-II were determined by HPLC. The location of the ascending hydrophobicity parameter was set: oligomycin B < oligomycin SC-II < oligomycin A < oligomycin F < oligomycin C.

[Physico-chemical properties and structure of oligomycin SC-II, produced by Streptomyces virginiae 17].

Under the screening programme for antibiotics with antifungal and immunosuppressive activities, Streptomyces virginiae 17 producing an oligomycin complex was isolated. Separation of the complex by HPLC showed that it contained two components at a ratio of 8:2. The physico-chemical characteristics of the components were investigated. The structure of oligomycin was assessed by 13C NMR and 1H NMR.

[Streptomyces sp. 17, an organism producing oligomycin SC-iI (culture characteristics and antibiotic biological properties)].

Under the screening programme for organisms producing substances with hypolipidemic and antifungal activity Streptomyces sp. 17 was isolated. The taxonomic properties of the strain were investigated. Active compounds, i.e. oligomycin A and oligomycin SC-II were isolated from a complex biosynthetic product. Oligomycin A showed high antifungal activity whereas oligomycin SC-II had also moderate antibacterial activity.

[Influence of natural complex compounds with hipolipidemic activity on expression of bacteria virulence factors].

Natural complex compounds with hipolipidemic activity, having considerable inhibitory effect on expression of bacteria virulence factors were isolated. Inhibitory properties of the compounds with respect to pyocyanine and protease formation, as well as their influence on the quorum sensing mechanism in Chromobacterium violacium were shown.

[Hyphomycetes as organisms producing cyclodepsipeptides].

The review deals with cyclodepsipeptides produced by hyphomycetes. The cyclodepsipeptide compounds are prospective new agents for the treatment of diseases of the infectious and pathophysiologic nature.

[Production of destruxins by coprotrophic Beauveria feline no. 7 strain].

Beauveria feline No. 7 strain was isolated from the shrewmouse wool and characterized by production of a complex of destruxins cyclodepsipeptides. The strain was shown to produce significant quatities of destruxin B and pseudodestruxin C. The destruxins were found to be able to inhibit formation of biofilms by Pseudomonas aeruginosa ATCC 27833.

[Organisms producing hypolipidemic compounds with antioxidant activity].

Complex compounds produced by fungal cultures of Lecanicilium and Beauveria with both high hypolipidemic and antioxydant activities were screened. Two fractions of the hypolipipidemic compounds with antioxidant activity of 95 and 75% in a dose of 25 mcg/ml were isolated.

[Complex of cyclosporins produced by Tolypocladium inflatum isolated from soil sample from Buriatiia].

A micromycete culture was isolated from a soil sample of Buryatiya and identified as Tolypocladium inflatum No. 2. The culture was shown to produce a complex of cyclosporins of unusual component structure: the content of cyclosporin A (55-60%) was the same as that in the substances produced by the majority of the described cultures, the content of cyclosporin B was much higher (about 40%) and the content of cyclosporin C was relatively low (about 3%). An appreciable content of cyclosporin (Leu4)Cs (3%) proved to be of interest.

[Influence of natural hypolipidemic compounds on biofilm formation by Pseudomonas strains].

Natural compounds showing considerable inhibitory effect on formation of biofilms by P. aeruginosa were selected. Synergism of the compounds with gentamicin with respect to both the inhibition of the biofilm formation and the gentamicin antibacterial effect was stated.

[Apoptotic endonuclease EndoG induces alternative splicing of telomerase catalytic subunit hTERT and death of tumor cells]. / Éndonukleaza EndoG indutsiruet al'ternativnyi splaising kataliticheskoi sub"edinitsy telomerazy hTERT i gibel' opukholevykh kletok.

Telomerase activity is known to be regulated by alternative splicing of its catalytic subunit hTERT (human Telomerase Reverse Transcriptase) mRNA. Induction of non-active spliced hTERT leads to inhibition of telomerase activity. However, very little is known about the mechanism of hTERT mRNA alternative splicing. The aim of this study was to determine the role of apoptotic endonuclease EndoG in alternative splicing of hTERT and telomerase activity. Strong correlation was found between expression of EndoG and hTERT splice-variants in 12 colon cancer cell lines. Overexpression of EndoG in СаСо-2 cells downregulated the expression of active full-length hTERT variant and upregulated non-active spliced variant. Reduction of full-length hTERT caused downregulation of telomerase activity, dramatically shortening of telomeres length during cell divisions, converting cells to the replicative senescence state, activation of apoptosis and finally cell death. These data indicated the participation of EndoG in alternative splicing of mRNA of telomerase catalytic subunit, regulation of telomerase activity and cell fate.

Reduction and protonation of the secondary quinone acceptor of Rhodobacter sphaeroides photosynthetic reaction center: kinetic model based on a comparison of wild-type chromatophores with mutants carrying Arg-->Ile substitution at sites 207 and 217 in the L-subunit.

After the light-induced charge separation in the photosynthetic reaction center (RC) of Rhodobacter sphaeroides, the electron reaches, via the tightly bound ubiquinone QA, the loosely bound ubiquinone Q(B) After two subsequent flashes of light, Q(B) is reduced to ubiquinol Q(B)H2, with a semiquinone anion Q-(B) formed as an intermediate after the first flash. We studied Q(B)H2 formation in chromatophores from Rb. sphaeroides mutants that carried Arg-->Ile substitution at sites 207 and 217 in the L-subunit. While Arg-L207 is 17 A away from Q(B), Arg-L217 is closer (9 A) and contacts the Q(B)-binding pocket. From the pH dependence of the charge recombination in the RC after the first flash, we estimated deltaG(AB), the free energy difference between the Q-(A)Q(B) and Q(A)Q-(B) states, and pK212, the apparent pK of Glu-L212, a residue that is only 4 A away from Q(B). As expected, the replacement of positively charged arginines by neutral isoleucines destabilized the Q-(B) state in the L217RI mutant to a larger extent than in the L207RI one. Also as expected, pK212 increased by approximately 0.4 pH units in the L207RI mutant. The value of pK212 in the L217RI mutant decreased by 0.3 pH units, contrary to expectations. The rate of the Q-(A)Q-(B)-->Q(A)Q(B)H2 transition upon the second flash, as monitored by electrometry via the accompanying changes in the membrane potential, was two times faster in the L207RI mutant than in the wild-type, but remained essentially unchanged in the L217RI mutant. To rationalize these findings, we developed and analyzed a kinetic model of the Q-(A)Q-(B)-->Q(A)Q(B)H2 transition. The model properly described the available experimental data and provided a set of quantitative kinetic and thermodynamic parameters of the Q(B) turnover. The non-electrostatic, 'chemical' affinity of the QB site to protons proved to be as important for the attracting protons from the bulk, as the appropriate electrostatic potential. The mutation-caused changes in the chemical proton affinity could be estimated from the difference between the experimentally established pK2J2 shifts and the expected changes in the electrostatic potential at Glu-L212, calculable from the X-ray structure of the RC. Based on functional studies, structural data and kinetic modeling, we suggest a mechanistic scheme of the QB turnover. The detachment of the formed ubiquinol from its proximal position next to Glu-L212 is considered as the rate-limiting step of the reaction cycle.

[Antimicrobial activity of natural hypolipidemic compounds].

Antibiotic activity of complex agents of actinomycete and fungal origin was studied in the programme of screening organisms producing substances with hypolipidemic activity. The majority of the agents were shown to be active against Aspergillus niger 137a and Candida albicans ATCC 885-653. Some of the agents were active against bacteria, including acid-fast ones.

[Plasmids of the cyanobacterium Synechocystis sp. 6803]. / Plazmidy tsianobakterii Synechocystis sp. 6803.

Three cryptic plasmids have been isolated from cyanobacterium Synechocystis sp. 6803::pSS2 (1.4 Md), pSS3 (36 Md), pSS4 (60 Md). Plasmid DNA was isolated in Cs-Cl-EB density gradient and analyzed by gel electrophoresis and electron microscopy by gel electrophoresis and electron microscopy techniques. The restriction map is constructed for plasmid pSS2 having the cleavage sites for Sau3a, HincII, HindIII, MspI restriction endonucleases. The plasmid may be used to construct the recombinant vector DNAs capable of autonomous replication in cyanobacterium Synechocystis sp. 6803. cells.

[Production of lincomycin by Micromonospora halophytica culture]. / Obrazovanie antibiotika linkomitsina ku'lturoi Micromonospora halophytica.

A Micromonospara culture designated as 991/78 with activity against gram-positive cocci and bacteria was isolated from samples of silt-covered substrates from the Amu-Darya. Directed screening on a selective medium supplemented with lincomycin in an amount of 50-100 micrograms/ml was used. Identification of the antibiotic produced by the culture showed it to be lincomycin. By its taxonomic features the culture was classified as belonging to Micromonospora (subgroup II, Cinnamomea) and in particular to M. halophytica (Weinstein, Luedemann, Oden, Wagman, 1968). Up to now, it was known that lincomycin was produced only by Streptomyces cultures.

[Streptomyces griseolus # 182--a novel organism producing oligomycin antibiotics. Taxonomy, fermentation, and isolation]. / Novyi produtsent antibiotikov oligomitsinovoi struktury Streptomyces griseolus No 182. Taksonomiia, fermentatsiia i vydelenie.

Target screening of natural immunosuppressors resulted in isolation of a strain of Streptomyces griseolus (No. 182) producing a complex of antifungal antibiotics. The strain proved to be an aerobe with the growth temperature of 26 to 28 degrees C. Morphological features and physiological properties of the strain were studied. Scanning electron microscopy revealed smooth, oval spores 1.10-1.25 mu in size. The findings showed that the strain belonged to Streptomyces griseolus. Unlike the previously described organisms producing the oligomycin complex the new strain formed straight or twisted sporophores and did not produce melanoid pigment or soluble pigment when grown on the Gauze mineral agar medium No. 1. The procedures for biosynthesis and chemical recovery of the antibiotic complex from the mycelium are described. The complex was shown to include 3 components at a ratio of 80:15:5 identified as oligomycins A, B and C respectively. The oligomycin complex was highly active against Aspergillus niger 137, Tolypocladium inflatum, Fusarium ocsisporum, Curvularia lunata 645 and Trichoderma alba F-32 (MIC 0.1-1.0 mcg/ml). The activity against yeast and bacterial cultures was observed only when the doses were higher than 100 mcg/ml.

[Screening of natural compounds with hypolipidemic activity]. / Skrining prirodnykh soedinenii s gipolipidemicheskoi aktivnost'iu.

In the screening programme for natural hypolipidemic compounds 702 strains of soil microorganisms were tested and 25 of them were selected because of their ability to produce compounds inhibiting sterol synthesis in Hep G2 hepatoma cells. The compounds were estimated in the microbiological model with Tolypocladium inflatum 106 as the test microbe. The 2nd stage of the screening resulted in isolation of 13 strains producing compounds with high hypolipidemic activity, analogous to or higher than the activity of lovastatin in the experimental models.

[Estimation of the efficacy of screened natural hypolipidemic compounds in a model of rabbit hypercholesterolemia]. / Otsenka éffektivnosti otobrannykh prirodnykh gipolipidemicheskikh veshchestv na modeli giperkholesterinemii u krolikov.

Thirteen strains producing hydrophobic compounds with high hypolipidemic activity were screened among 657 tested strains of fungi, actinomycetes and bacteria with the use of 2 models. The further aim of the study was to estimate the efficacy of the compounds with respect to their ability to inhibit cholesterol synthesis in vivo. For that purpose a model of hyperlipidemia in rabbits was used. The model provided screening of 9 new compounds that showed satisfactory hypolipidemic effect evident from a significant decrease of the lipid levels in the rabbit serum. The study of the serum lipid profile revealed that the inhibitory effect of compounds No. 16 and No. 281 was similar to that of lovastatin whereas the serum level of general cholesterol remained decreased for a longer period. Compound No. 25 was of interest because of its possible use in low doses and significant effect on the serum triglyceride fraction.