Synthesis and biological evaluation of 4,4-dimethyl-5,5-di(1-methylethyl)-2,3,4,5-tetrahydro-1 H-dipyrrolo[3,4-d:2,1-f][1,2]azasiline-1,3-dione and other pyrrolediones as new antibacterial active agents.

The UV-light induced photosubstitution of 3,4-dibromo-2,5-dihydro-1H-2,5-pyrroledione (2) [1] with pyrrole derivatives leads to 3-mono- and 3,4-disubstituted pyrrolediones depending on the starting material. These pyrrole homologues of arcyriarubin A (1) are further processed by nucleophilic substitution of the remaining bromine substitutent with pyrrolidine. Cleavage of the protecting group affords the free pyrrole substituents. By UV-light irradiation the azasiline-system (6) is accessible, and its structure was established by X-ray methods. The in vitro antibacterial activity of the pyrrolediones was evaluated, and a strong activity of the compounds 4, 7, 8 and 12 against the methicillin- and ciprofloxacin-resistant bacterium Staphylococcus aureus 134/94 was established.

New macrodiolide antibiotics, 11-O-monomethyl- and 11, 11'-O-dimethylelaiophylins, from Streptomyces sp. HKI-0113 and HKI-0114.

Elaiophylin (1) and two new methyl derivatives, 11-O-monomethylelaiophylin (2) and 11,11'-O-dimethylelaiophylin (3), were isolated from the mycelium cake of Streptomyces strains HKI-0113 and HKI-0114. The structures of 2 and 3 were determined by mass spectrometric and NMR investigations. Compounds 2 and 3 display antimicrobial and moderate cytotoxic activities.

Ampullosporin, a new peptaibol-type antibiotic from Sepedonium ampullosporum HKI-0053 with neuroleptic activity in mice.

Ampullosporin (I; Ac-Trp-Ala-Aib-Aib-Leu-Aib-Gln-Aib-Aib-Aib-Gln-Leu-Aib-Gln-Leuol) was isolated from the mycelium of Sepedonium ampullosporum as a new 15-membered peptaibol-type antibiotic. The structure was determined by mass spectrometric and two-dimensional NMR experiments. Ampullosporin displays narrow-spectrum antibacterial and antifungal activity, induces pigment formation by Phoma destructiva, causes hypothermia and decreased spontaneous locomotor activity in mice in dosages > 1 mg/kg.

Lipohexin, a new inhibitor of prolyl endopeptidase from Moeszia lindtneri (HKI-0054) and Paecilomyces sp. (HKI-0055; HKI-0096). I. Screening, isolation and structure elucidation.

Lipohexin was isolated as a novel lipohexapeptide (I) (C39H68N6O9) from three fungal strains, Moeszia lindtneri HKI-0054, Paecilomyces sp. HKI-0055 and Paecilomyces sp. HKI-0096. The structure was elucidated by detailed mass spectrometric and NMR experiments. The proline-containing peptide displays moderate antibacterial activity against Bacillus subtilis ATCC 6633 and inhibits competitively the prolyl endopeptidase from human placenta.

Chrysospermins, new peptaibol antibiotics from Apiocrea chrysosperma Ap101.

Four new members of peptaibol antibiotics, designated as chrysospermins A, B, C, and D, were isolated from the mycelium of Apiocrea chrysosperma Ap101 by solvent extraction, silica gel chromatography and preparative recycling HPLC. Their structures as new nonadecapeptides were settled by detailed spectroscopic analysis and chemical degradation experiments. The chrysospermins display antibacterial and antifungal activity, and induce pigment formation by the fungus Phoma destructiva.

Aurantimycins, new depsipeptide antibiotics from Streptomyces aurantiacus IMET 43917. Production, isolation, structure elucidation, and biological activity.

Aurantimycins A (1), B (2) and C (3) were isolated from the mycelium of Streptomyces aurantiacus JA 4570 as new representatives of the azinothricin group of hexadepsipeptide antibiotics. Their structures were settled by X-ray diffraction analysis of crystalline aurantimycin A (1), high field homo- and heteronuclear 2D NMR experiments, high-resolution mass spectrometry and amino acid analysis. Aurantimycins are characterized by a new side chain containing fourteen carbon atoms. They display strong activity against Gram-positive bacteria and cytotoxic effects against L-929 mouse fibroblast cells.

Helioferins; novel antifungal lipopeptides from Mycogone rosea: screening, isolation, structures and biological properties.

Helioferins A and B were detected as novel aminolipopeptides in cultures of Mycogone rosea DSM 8822 in the course of a screening for mediators of helianthate anion transfer from aqueous to toluene phases. Their structures as novel antibiotics and cytotoxic agents were elucidated by mass spectrometry and NMR spectroscopic methods. Antimicrobial activity was estimated against Candida albicans and Gram-positive bacteria including Mycobacterium spp.

[Biosynthesis of anthracycline: a new interpretation of the results for daunomycin biosynthesis]. / Biosynthese der Anthracycline: eine Neuinterpretation der Ergebnisse zur Daunomycin-Biosynthese.

On the basis of literature data and our own experiments the "late" biosynthetic pathway to daunomycin has been interpreted from a new point of view considering both the in vivo biosynthesis and formation of shunt products. In contrast to existing hypotheses proposed by other authors we discuss a modified sequence leading to C-11 oxidation and, as a consequence, understand epsilon-rhodomycinone as a shunt product instead of a biosynthetic intermediate. In addition, a new hypothesis about the "early" steps of the ring formation from polyketides by a sequence of enzyme reactions has been proposed.

Physiochemical characterization of substituted chromeno[4,3-b][1,5]benzodiazepine stereoisomers designed as cell membrane active antitumor agents.

As an alternative to naturally occurring pyrrolo[2,1-c][1,4]benzodiazepines (e.g., antramycin) which possess properties of DNA alkylation, we have designed several antileukemic chromeno[4,3-b][1,5]benzodiazepine derivatives with potential activity toward leukemia cell membranes and the cyclic nucleotide system. The cis and trans diastereoisomers were characterized by NMR. The absolute configurations of the enantiomers were established by X-ray diffraction and circular dichroism (CD) measurements. By means of absorption spectroscopy and determinations of fluorescence and fluorescence decay, it was found that the cancerostatically active compound (+)(6aR, 13aS)-3,4-dimethoxy-10,11-dimethyl-6,6a,7,8,13, 13a-hexahydrochromeno[4,3-b][1,5]benzodiazepine (ZIMET 54/79) and its biologically inactive (-) enantiomer (ZIMET 55/79) interact with liposomal membranes. At pH values of 6.0 and 7.3 the long-wave absorption bands of these agents showed weak bathochromic and hypochromic effects upon addition of neutral, and positively and negatively charged phosphatidylcholine and phosphatidylcholine/cholesterol liposomes. Such spectral changes are interpreted as resulting from the binding of both agents to phospholipid bilayers. Steady-state determinations using the membrane probe 1-anilino-8-naphthalenesulfonic acid (1,8-ANS) led to the observation of a small decrease in fluorescence intensity in the presence of either agent. Time-resolved measurements demonstrate that the mechanism of action of the agents occurs mainly through the partial displacement of probe molecules from regions of hydrophobic binding to areas of greater solvent accessibility. No significant differences in binding between the cancerostatically active and inactive enantiomers with liposomes (archiral systems) were detectable on the basis of spectrophotometric and fluorescence determinations. Cell membrane bound adenylate cyclase is stimulated by ZIMET 54/79, resulting in an increase of 103% in the level of cAMP in mouse L1210 leukemia cells. On examination of structure-activity relationships, it was found that the biological activity (leukemia L1210, P388, Lewis lung carcinoma, melanoma B16, increase in cAMP) is correlated with the particular configuration (6aR,13aS) and type of substituent at positions 3 and 4 of the benzo ring in the case of alkoxy groups and positions 10 and 11 for methyl groups. No activity was detected toward DNA/RNA using microbial test systems.

Kinetics of secondary metabolite formation by wild type and mutant strains of Streptomyces griseus.

In a particle containing medium, the kinetics of formation of secondary metabolites of a Streptomyces wild type and a mutant strain were determined by spectrophotometric measurements of the anthracyclinone pigments and by the analysis of antibiotic activity of the substances produced. The results were related to the physiological state of the culture derived from the oxygen supply. The total cultivation time was about 400 hours. The production of secondary metabolites started at the end of the logarithmic growth phase (after about 30 hours). During the following cultivation remarkable differences between the two strains regarding the formation of pigments and antibiotics occurred. In the wild type strain producing daunomycinone glycosides and related compounds with antibiotic activity, these antibiotics are active as inhibitors (negative feedback). Therefore, at a certain concentration of antibiotics, the de-novo formation of anthracycline molecules was impaired. In the mutant strain, as the result of a genetic change, the secondary metabolite production was shifted to nonglycosylated compounds. The production of these substances is not influenced by feedback inhibition as in the case of the wild type strain. From that reason the amount of pigment increased slightly throughout the course of the experiment. Under our experimental conditions the measurement of oxygen supply was a suitable indicator of the physiological state of culture.

[Structure-activity relation for rhodomycin-type antibiotics and the inhibition kinetics of single-stranded and double-stranded DNA- and RNA-viruses]. / Sviaz' mezhdu strukturoi i deistviem antibiotikov rodomitsinovoi gruppy na tormoznuiu kinetiku DNK- i RNK-virusov odnospiral'nogo i dvukhspiral'nogo tipov.

The antiviral activity of anthracycline antibiotics of rhodomycin group was investigated by two independent methods which determined the infectious units or antigenicity of the viruses. The action of rhodomycin depended on the structure, number, and position of amino sugar in aglycon. The antiviral activity was found to increase in serial order: iremycin--adriamycin--daunomycin--alpha-rubicin--beta-rhodom ycin-- violamycin B I complex by inhibition kinetics determined with adenovirus.

[Relationships between structure and activity of anthracycline antibiotics of the rhodomycin group: inhibition kinetics of DNA and RNA viruses of the double- and single-strand types]. / Beziehungen zwischen Struktur und Wirkung von Anthracyclin-Antibiotika der Rhodomycingruppe: Hemmungskinetik der DNS- und RNS-Viren vom Doppelstrang- und Einstrang-Typ.

Antiviral activity from anthracycline antibiotics of rhodomycin-type was investigated by two independent methods, which determined the infectious units and antigenity of incomplete virions. The action of rhodomycin was dependent on structure, number and position of amino sugar, which is in aglycon. The viruses of double-stranded DNA and RNA viruses was stronger inhibited as single-stranded RNA viruses. The antiviral activity were found to increase in the serial order iremycin less than adriamycin less than daunomycin less than alpha-rubicin I less than beta-rhodomycin I less than violamycin BI-complex by inhibition kinetic determined from Adeno virus.

Compartmentation of enzymes interconverting aclacinomycins in Streptomyces species AM 33352.

The enzymatic interconversion of the aclacinomycins A (I), Y (II), and B (III) by Streptomyces spec. AM 33352/S 182 producing these aklavinone glycosides was investigated. The enzymes converting I to II and III, as well as vice versa, are located within different compartments separated by the cytoplasmic membrane. Aclacinomycin A (I) is biotransformed to II and III by the cell-free mycelium extract while the entire mycelium carries out the same type of conversion towards the opposite direction. Changes of enzyme activity are correlated to alterations in the ratio of aklavinone glycosides throughout the fermentation. A hypothesis is developed concerning the role of compartmentized oxidoreductase(s) in the passive flux of I from inside the cells to outside.

Streptavidin assay by means of biotinylated actinophages.

Using D-biotinyl-N-hydroxysuccinimide ester, biotin was covalently attached to actinophage SLE 111. The chemically modified actinophage preparation (SLE 111-BIO) was prevented from forming plaques by biotin-binding proteins, such as streptavidin and avidin. The avidin concentration at 50% inactivation of biotinylated actinophages was 0.5 micrograms/ml. The streptavidin assay was useful as pre-selection method during the screening and improvement work with streptavidin-producing microorganisms.

Inhibitors of the cleavage of aclacinomycins.

The reductive cleavage of the aclacinomycins A (I), Y (II), and B (III) by intact mycelia or subcellular fractions of the producer strain S. spec. AM 33352/F43 is suppressed in the presence of uncouplers, complex-forming agents, detergents, and some metal anions such as chromate. Increased concentration of the latter in complete cultures caused rearrangement of I to III.

[The synthesis and biologic activity of analogs of 1,4-benzoquinone-guanylhydrazone-thiosemicarbazone. 2. Substitution at the quinone ring by alkyl groups]. / Zur Synthese und biologischen Wirksamkeit von Analogen des 1,4-Benzochinon-guanylhydrazon-thiosemicarbazons. 2. Mitteilung: Substitution am Chinonring durch Alkylreste.

Because of the anticancer activity of 1,4-benzoquinone-guanylhydrazone-thiosemicarbazone (1a) some analogues were synthesized, containing alkyl groups at the quinone moiety. If necessary, the structure of the obtained compounds was confirmed by 1H-NMR-spectroscopy. The anticancer and the antibacterial activities were investigated. The guanylhydrazone-thiosemicarbazones of tolu-,p-xylo-and thymo-quinone showed much lower activities not only against the murine leukemias L 1210 and P 388, but also against Bacillus subtilis ATCC 6633. No correlation could be found between the biological activity and the redox potential.