Mechanism of inhibition of DNA gyrase by cyclothialidine, a novel DNA gyrase inhibitor.

We investigated how cyclothialidine (Ro 09-1437), a novel DNA gyrase inhibitor belonging to a new chemical class of compounds, acts to inhibit Escherichia coli DNA gyrase. Cyclothialidine up to 100 micrograms/ml showed no effect on DNA gyrase when linear DNA was used as a substrate. Under the same conditions, quinolones, which inhibit the resealing reaction of DNA gyrase, caused a decrease in the amount of linear DNA used.

Synthesis and structure-activity relationships of a novel antifungal agent, azoxybacilin.

A new antifungal substance, azoxybacilin (an unusual amino acid with an azoxy moiety) and its derivatives have been synthesized from Boc-L-Asp-OtBu utilizing the Moss procedure for the preparation of the azoxy moiety. The ester derivative, Ro 09-1824, showed more potent antifungal activity and a broader antifungal spectrum than azoxybacilin did.

A new methionine antagonist that has antifungal activity: mode of action.

A new antifungal, azoxybacilin (an unusual amino acid with an azoxy moiety) was identified from Bacillus cereus, and its in vitro antifungal activity and mode of action were investigated. Azoxybacilin was active against a broad spectrum of fungi. It was especially active against mycelial fungi, such as Aspergillus, and did not show antibacterial activity.

Tetrafibricin, a novel non-peptide fibrinogen receptor antagonist, induces conformational changes in glycoprotein IIb/IIIa.

Arg-Gly-Asp (RGD) is an amino acid sequence in fibrinogen recognized by platelet glycoprotein (GP) IIb/IIIa. Recently, it was found that RGD peptide binding to GPIIb/IIIa leads to conformational changes in the complex that are associated with the acquisition of high-affinity fibrinogen-binding function. In this study, we found that tetrafibricin, a novel non-peptidic GPIIb/IIIa antagonist, induced similar conformational changes in GPIIb/IIIa as did RGD peptides.

Involvement of cell wall beta-glucan in the action of HM-1 killer toxin.

HM-1 killer toxin secreted from Hansenula mrakii inhibits the growth of Saccharomyces cerevisiae cells by interfering with beta-1,3-glucan synthesis. We found that HM-1 killer toxin killed intact cells but not protoplasts. In addition, cells lacking the functional KRE6 allele (kre6 delta) became resistant to higher concentration of HM-1 killer toxin.

The disposition of the tolcapone 3-O-methylated metabolite is affected by the route of administration in rats.

Catechol-O-methyltransferase (COMT) catalyses the transfer of the methyl group from S-adenyl-L-methionine (SAM) to one of the hydroxy groups of a catechol, usually the hydroxy group in position 3. COMT is present mainly in a soluble form (S-COMT) in the cytosol, but a small fraction is bound to cell membranes (MB-COMT). MB-COMT has higher affinity for the catechol substrate than does S-COMT by a factor of > 10, and high MB-COMT activity is observed in the intestinal muscle layer.

Fusarium merismoides Corda NR 6356, the source of the protein kinase C inhibitor, azepinostatin. Taxonomy, yield improvement, fermentation and biological activity.

Fungal strain NR 6356, Fusarium merismoides Corda, was discovered as the source of the protein kinase C (PKC) inhibitor, azepinostatin. The strain was identified based on its growth on potato sucrose agar, slender conidial shape, characteristic polyphialide and production of abundant chlamydospores. Fusarium aquaeductuum Lagh.

Effect of etretinate (aromatic retinoid) treatment during gestation and lactation periods on viability and somatic growth in F1 rats.

When female SD rats were continuously treated with Etretinate throughout pre-mating, gestation, and lactation periods, the resulting F1 pups exhibited low viability and inhibition of somatic growth after birth (Hummler et al., 1981). Nevertheless, these pups showed no notable change in body weight and external appearance at birth.

The anti-tumor arotinoid Ro 40-8757 protects bone marrow from the toxic effects of 5-fluorouracil.

Combination therapy with 5-fluorouracil (5-FU) and the arotinoid Ro 40-8757 (mofarotene) of established chemically induced mammary tumors in rats was examined. The cytotoxic drug was administered weekly and Ro 40-8757 was given daily. The dose of Ro 40-8757 used in this study did not have an effect on tumor burden but, in combination with 5-FU, significantly enhanced the reduction in tumor burden and tumor number.

3-O-methyldopa attenuates the effects of Madopar on the haloperidol-induced cataleptic behavior and the locomotor activity in the mouse.

The effects of Madopar (levodopa plus benserazide) on the cataleptic behavioral response to haloperidol and on the locomotor activity in mice were quantitatively compared before and after the administration of 3-O-methyldopa (3OMD). The intraperitoneal administration of 3OMD (200-400 mg/kg) alone did not modify the haloperidol (1.0 mg/kg s.

Differential regulation of c-fos gene expression by two types of human endothelin receptor in Chinese hamster ovary cells.

To investigate the nuclear signalling pathway induced by endothelin (ET) isopeptides, we have established permanent Chinese hamster ovary (CHO) cell lines, CHO-ETA/fos-lacZ and CHO-ETB/fos-lacZ, that produce both a c-fos-beta-galactosidase fusion protein and either the type A or the type B human ET receptor. These cell lines permitted a colorimetric measurement of c-fos expression, which was induced by the signal transduction system with ET receptors and ET isopeptides. We found that the ET-1-dependent c-fos expression was so efficient that it could respond to low concentrations (even a physiological concentration) of ET-1.

Human endothelin receptor ETB. Amino acid sequence requirements for super stable complex formation with its ligand.

ETB type endothelin receptor (ETBR) forms a stable complex with its ligand endothelin-1 (ET-1). The ligand-receptor complex can survive in the presence of 2% SDS and migrate in SDS-polyacrylamide gel electrophoresis at reduced temperature. This is not the case for the ETA type endothelin receptor (ETAR).

Identification of a ligand-binding site of the human endothelin-A receptor and specific regions required for ligand selectivity.

To investigate the ligand-binding site of the human endothelin-A-receptor subtype (ETA), we have produced various chimeric and mutated receptors in chinese hamster ovary cells. The substitution of Lys140 with Ile located in the C-terminus of the second transmembrane region caused a 13-fold reduction in affinity for endothelin-1 (ET-1) and 3.6-fold lower Bmax than those values for the original receptor.

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

Random amplified polymorphic DNA (RAPD) analysis was evaluated for the selection and elimination of bacterial strains used in microbial screening. For this pilot study we used eight bacterial strains producing fragin and two Pseudomonas fragi strains, which are often isolated during the screening. A dendrogram constructed by the statistical analysis using parsimony, PAUP, based on the band patterns of RAPD with primer R28 was in good correlation with the results of DNA-DNA hybridization, HPLC analysis of metabolites, and conventional morphological and physiological characterization.

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.

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

For efficient fungal strain selection in microbial screening, we applied the random amplified polymorphic DNA (RAPD) method using the polymerase chain reaction (PCR). In order to evaluate this system, the genus Trichoderma was employed, because its species are difficult to distinguish from each other. We selected an appropriate oligonucleotide decamer, R28 (5'-ATGGATCCGC), determined the optimal cycles of PCR as 30 cycles, simplified the template preparation method, and determined optimal concentrations of the template and Taq DNA polymerase.

Amelioration by aniracetam of abnormalities as revealed in choice reaction performance and shuttle behavior.

To delineate the possible effects of aniracetam PO on abnormal behaviors, we analyzed disrupted shuttle behavior and choice reaction (CR) performance in both aged and juvenile animals subjected to an ischemic (permanent occlusion of both carotid arteries)-hypoxic (17-min exposure to 93% N2 and 7% O2 mixture gas) or ischemic (20-min occlusion of both carotid arteries) insult and/or treated with methamphetamine given IP. Aniracetam at single PO doses of 10 and 30 mg/kg significantly decreased the number of incorrect lever pressings induced by IP methamphetamine in young adult rats subjected to the CR test battery. A 21-day PO regimen with aniracetam (30 mg/kg/day) resulted in an increase in the number of correct responses and a decrease in the CR latency as detected in the CR task with young adult rats inflicted with an ischemic-hypoxic insult.

Data management for toxicological studies.

Organized data management increases the reliability of statistical analysis. The basic purpose of data management is to assure the integrity and the quality of data. To assure data validity, establishing a checking system, such as data audit, would be desirable at the following points: protocol design, supervision of study schedule, definition of data, data collection, choice of tests and procedures, verification, data checking, data recording, data handling, data analysis, and data validation.

Cyclothialidine, a novel DNA gyrase inhibitor. II. Isolation, characterization and structure elucidation.

Cyclothialidine is a novel DNA gyrase inhibitor produced by Streptomyces filipinensis NR 0484. It was isolated from the culture broth by charcoal adsorption, Diaion HP-21, Amberlite CG-50, DEAE Toyopearl, and Toyopearl HW-40 SF column chromatography. The structure of cyclothialidine was determined to be a unique twelve membered lactone by amino acid analysis and various 2D-NMR experiments.

Cyclothialidine, a novel DNA gyrase inhibitor. I. Screening, taxonomy, fermentation and biological activity.

Streptomyces filipinensis NR 0484 produced a new DNA gyrase inhibitor, cyclothialidine. It showed potent activity against DNA gyrases from Escherichia coli and Micrococcus luteus.

Hispidospermidin, a novel phospholipase C inhibitor produced by Chaetosphaeronema hispidulum (Cda) Moesz NR 7127. II. Isolation, characterization and structural elucidation.

Hispidospermidin (1) is a novel phospholipase C inhibitor produced by Chaetosphaeronema hispidulum (Cda) Moesz NR 7127. Its structure (C25H47N3O) has been elucidated as a cage compound with a trimethylspermidine side chain based on various NMR studies, including 1H-1H COSY, 13C-1H COSY, HOHAHA, HMBC, COLOC and long range J C-H resolved 2D spectroscopy. The absolute configuration of 1 has been elucidated by modified Mosher's method on the (R)- and (S)-MTPA amides of a derivative of 1.

Hispidospermidin, a novel phospholipase C inhibitor produced by Chaetosphaeronema hispidulum (Cda) Moesz NR 7127. I. Screening, taxonomy, and fermentation.

A novel phospholipase C inhibitor, hispidospermidin, was discovered from a fungal culture broth. The producing fungus, NR 7127, formed abundant pycnidia on banana leaf agar under near UV light. The ostiolate pycnidia were dark colored with a short beak possessing numerous protruding setae.

Tetrafibricin: a nonpeptidic fibrinogen receptor inhibitor from Streptomyces neyagawaensis. (II). Its antiplatelet activities.

Tetrafibricin; a nonpeptidic fibrinogen inhibitor from microbial origin, showed potent antiaggregation activities on human platelet aggregation induced by either ADP, thrombin or collagen (IC50s = 5.6, 7.6 and 11 microM, respectively) in platelet rich plasma.

Tetrafibricin: a nonpeptidic fibrinogen receptor inhibitor from Streptomyces neyagawaensis (I). Its GPIIb/IIIa blockage on solid phase binding assay.

Tetrafibricin is a novel nonpeptidic fibrinogen receptor inhibitor isolated from Streptomyces neyagawaensis NR0577. Its competitive and selective fibrinogen receptor blockage was demonstrated in this study. Tetrafibricin competitively inhibited (Ki = 9.