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At least 145 records · Page 8Linked to original sources
PubMed1982

Studies on a new antibiotic M-92 produced by Micromonospora. III. Biological activities.

The six major components of M-92, a new antibiotic complex produced by Micromonospora verruculosa MCRL 0404 showed a similar type of antimicrobial spectrum. Among these components, VA-2 exhibited the most potent antimicrobial activity, particularly significantly against some Gram-positive bacteria and Neisseria. VA-2 and BN-1 also exhibited marked inhibitory effects against L-forms of Staphylococcus aureus 209P and Mycoplasma. The MICs of VA-2, BA-4 and BN-1 were remarkably affected by the pH of the test medium, the inoculum size and the amount of horse serum added in the medium. By intraperitoneal administration, these components showed good protective effects in mice infected intraperitoneally with Staphylococcus aureus Smith. However, the protective effect decreased remarkably by other administration routes. In addition, components such as VA-2 and BN-1 exhibited cytotoxicity against HeLa S-3 cells in vitro and excellent in vivo antitumor activity against Ehrlich carcinoma. VA-2 possessed a high order of acute toxicity to mice [LD50:1.9 mg/kg (i.p.); 1.8 mg/kg (i.v.)], but others were relatively less toxic.

Animals↗
PubMed1982

Production of antibiotic SU-2 complex by a 2-deoxystreptamine idiotroph of Micromonospora sagamiensis.

A 2-deoxystreptamine idiotrophic mutant of Micromonospora sagamiensis, KY 11509, was found to produce unknown antibacterial substances, which were named SU-2 complex. Each component, SU-1, SU-2 and SU-3 were isolated from a culture broth of KY 11509. Chromatographic data suggested that these components were new antibiotics. The antibiotics exhibited potent and broad spectrum of antibacterial activity. The amount of SU-1, SU-2 and SU-3 production reached their maximum level (197, 82 and 58 micrograms/liter, respectively) in 3 to 4 days. Addition of cobalt chloride markedly stimulated SU-1 production but suppressed SU-2 and SU-3 production. Isolation of a mutant possessing a higher productivity of SU-2 complex is also described.

Anti-Bacterial Agents↗
PubMed1983

Sagamicin and the related aminoglycosides: fermentation and biosynthesis. III. Isolation and characterization of Micromonospora sagamiensis mutants blocked in gentamicin C1 pathway.

Production of sagamicin and gentamicin C1 in Micromonospora sagamiensis was regulated by cobalt ion. In a parental strain, KY11510, cobalt ion stimulated gentamicin C1 production and suppressed sagamicin production. By ultraviolet light or N-methyl-N'-nitro-N-nitrosoguanidine treatment, six mutants blocked in gentamicin C1 biosynthesis were obtained from KY11510. These mutants were classified into two types. The first type, four mutants, produced no gentamicin C1 even when cobalt ion was added to the fermentation. The second type, two mutants, produced a small amount of gentamicin C1 when a high concentration of cobalt ion was added. Based on biotransformation experiments, these mutants appeared to be blocked at the 6'-C-methylation step in the biosynthesis of gentamicin C1. The mutants showed an increased production of sagamicin. In addition, cobalt ion stimulated sagamicin production in the mutants. The mechanism of cobalt regulation in the parent and the mutants is discussed.

Aminoglycosides↗
PubMed1984

Biosynthesis of astromicin and related antibiotics. II. Biosynthetic studies with blocked mutants of Micromonospora olivasterospora.

An inosamine-idiotrophic mutant, KY11559, which produced no astromicin unless scyllo-inosamine was added to the fermentation medium, was isolated from Micromonospora olivasterospora. Biotransformation studies were performed with resting cells of this mutant and compounds assumed to be precursors of 1,4-diaminocyclitol (fortamine). Scyllo-inosose, scyllo-inosamine and FU-10 were converted to astromicin. A number of mutants blocked in the biosynthesis of astromicin were developed from M. olivasterospora, and the intermediates accumulated by these mutants were isolated and identified. Twenty-five blocked mutants were classified into 10 groups, based on their complementation patterns by cosynthesis experiments. Further, utilizing these blocked mutants and the isolated compounds, biotransformation analyses were performed. The results showed that the amination at position 4 in fortamine occurred after formation of the pseudodisaccharide. Subsequently, the aminosugar and aminocyclitol moieties were aminated, methylated, dehydroxylated, epimerized and acylated to produce astromicin. Thus it was demonstrated that the astromicin biosynthetic pathway has a unique feature which is not found in the biosynthesis of other aminoglycoside antibiotics.

Aminoglycosides↗
PubMed1986

Clostomicins, new antibiotics produced by Micromonospora echinospora subsp. armeniaca subsp. nov. I. Production, isolation, and physico-chemical and biological properties.

A soil isolate named as Micromonospora echinospora subsp. armeniaca subsp. nov. KMR-593 was found to produce at least five related antibiotics, clostomicins, active against Gram-positive bacteria including anaerobes. From the physico-chemical properties, one of these components was identified with lipiarmycin and others were found to be new antibiotics. Each component includes two chlorine atoms and the molecular weights of A and B2, C, and D are 1,058, 1,042 and 1,056, respectively. The structural differences were characterized by NMR analyses.

Aminoglycosides↗
PubMed1987

K-259-2, a new inhibitor of Ca2+ and calmodulin-dependent cyclic nucleotide phosphodiesterase from Micromonospora olivasterospora.

K-259-2, a new inhibitor of Ca2+ and calmodulin-dependent cyclic nucleotide phosphodiesterase, was isolated from the cultured broth of Micromonospora olivasterospora K-259. K-259-2 has an anthraquinone moiety in its structure. IC50 values for the effect of K-259-2 against Ca2+ and calmodulin-stimulated activity of the enzyme preparations from bovine brain and heart were 6.6 and 2.9 microM, respectively. On the other hand, basal activity (the activity in the presence of ethylene bis(oxyethylenenitrilo)tetraacetic acid (EGTA) instead of Ca2+/calmodulin) of the bovine brain enzyme, calmodulin-independent cyclic nucleotide phosphodiesterase from bovine heart, and protein kinase C from rat brain were inhibited by K-259-2 to a lesser extent with IC50 values of 27.4, 40.7 and 45.8 microM, respectively.

Anthraquinones↗
PubMed1987

K-13, a novel inhibitor of angiotensin I converting enzyme produced by Micromonospora halophytica subsp. exilisia. I. Fermentation, isolation and biological properties.

A novel inhibitor of angiotensin I converting enzyme (ACE), designated K-13, was isolated from the culture broth of Micromonospora halophytica subsp. exilisia K-13. K-13 inhibited ACE non-competitively when hippuryl-L-histidyl-L-leucine was used as a substrate. The inhibition constant (Ki) was 0.349 microM. K-13 hardly inhibited carboxypeptidase A, trypsin, alpha-chymotrypsin, leucine aminopeptidase, and aminopeptidase B even at a level of 61 microM. When K-13 was administered intravenously to rats, it inhibited the pressor response to angiotensin I.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1988

Sch 37137, a novel antifungal compound produced by a Micromonospora sp. Taxonomy, fermentation, isolation, structure and biological properties.

A new antifungal compound, Sch 37137, was isolated from the cultured broth of a Micromonospora sp., SCC 1792. Sch 37137 is structurally related to A 19009, a dipeptide previously discovered from a Streptomyces sp. The compound was weakly active against species of Candida and dermatophytes (mean MICs greater than or equal to 128 micrograms/ml) in Sabouraud dextrose, yeast-nitrogen and modified Eagles minimum essential media; however activity against Candida sp. (mean MICs greater than or equal to 12 micrograms/ml) and dermatophytes (mean MICs greater than or equal to 0.8 microgram/ml) significantly improved in MA medium.

Amino Acids, Diamino↗
PubMed1988

Neihumicin, a new cytotoxic antibiotic from Micromonospora neihuensis. I. The producing organism, fermentation, isolation and biological properties.

A new cytotoxic and antifungal antibiotic, neihumicin, was isolated from the culture broth of a soil isolate identified as Micromonospora neihuensis Wu, sp. nov. Neihumicin shows in vitro cytotoxicity against KB tissue culture cells (ED50 0.94 micrograms/ml) as well as antifungal activity against Saccharomyces cerevisiae ATCC 9763.

Antibiotics, Antineoplastic↗
PubMed1989

Biosynthetic similarity between Streptomyces tenjimariensis and Micromonospora olivasterospora which produce fortimicin-group antibiotics.

The profile of bioconversion products of istamycin (IS) components by a blocked IS mutant of Streptomyces tenjimariensis that lost IS-productivity suggested a possible biosynthetic pathway of IS similar to that of fortimicin (FT) by Micromonospora olivasterospora. Both organisms are resistant to the antibiotics produced by each other. Based on these similarities, they were examined for their capability to convert an FT-intermediate (FT-B) and IS-intermediates (IS-A0 and -B0) through their biosynthetic pathways. S. tenjimariensis formed 1-epi-FT-B, 2''-N-formimidoyl-FT-A (= dactimicin) and 1-epidactimicin (a new antibiotic) from FT-B. On the other hand, M. olivasterospora converted IS-A0 and -B0 to 2''-N-formimidoyl-IS-A (= IS-A3) and -B (= IS-B3), respectively. Thus, the similarity in antibiotic biosynthesis was confirmed between these FT-group antibiotic-producing organisms. It was also found that the major fermentation product of M. olivasterospora is not FT-A (astromicin) but dactimicin.

Aminoglycosides↗
PubMed1989

LL-E19085 alpha, a novel antibiotic from Micromonospora citrea: taxonomy, fermentation and biological activity.

A new antibacterial antibiotic, designated LL-E19085 alpha, was isolated from the fermentation broth of an actinomycete strain. Based on cultural, physiological, morphological and chemical characteristics, culture LL-E19085 was identified as a new subspecies of Micromonospora citrea. Antibiotic LL-E19085 alpha demonstrated potent activity against a spectrum of Gram-positive aerobic and anaerobic bacteria.

Animals↗
PubMed1990

New analogues of rosaramicin isolated from a Micromonospora strain. I. Taxonomy, fermentation, isolation and physico-chemical and biological properties.

Antibiotics 6108 A1, B, C and D, a new series of analogues of rosaramicin, were found together with rosaramicin, juvenimicin A4 and M-4365 A1 from the cultured broth of strain BA06108 which was assigned to be a new species of Micromonospora. 6108 A1 and C showed inhibitory activity against Gram-positive and some Gram-negative bacteria as potent as rosaramicin and exhibited low acute toxicity in mice. However, 6108 B showed less potent antimicrobial activity and 6108 D showed higher toxicity than those two antibiotics.

Animals↗
PubMed1991

The effect of methylation inhibitors on citreamicin biosynthesis in Micromonospora citrea.

When the citreamicin-producing organism Micromonospora citrea NRRL 189351 was incubated in the presence of the methylation inhibitors sinefungin or aminopterin, biosynthesis of the zeta component was stimulated approximately 20 to 200-fold above the level normally produced. Inhibition of a second methylation reaction, which is superficially very similar to the first, was not detected. Other known methylation inhibitors failed to yield any change in the natural pattern of citreamicins produced. This approach is an excellent route for preparing citreamicin zeta, which can be used as a substrate for semi-synthesis or for further biosynthetic studies.

Adenosine↗
PubMed1991

Isolation and characterisation of an aminoglycoside phosphotransferase from neomycin-producing Micromonospora chalcea; comparison with that of Streptomyces fradiae and other producers of 4,6-disubstituted 2-deoxystreptamine antibiotics.

The gene (aphA-5c) encoding for aminoglycoside-O-phosphoryl-transferase (APH(3')-Vc) from Micromonospora chalcea 69-683 was cloned by expression in Streptomyces lividans; it showed strong nucleic and amino acid similarities with previously described streptomycetes aph genes. S1 mapping of the 5' region indicated that, as with several streptomycete genes, transcription apparently initiates at the translation start codon, with no extragenic ribosome binding site. Comparison of the flanking sequences of the actinomycete aph genes indicates considerable divergence, which is not consistent with the notion that clustered biosynthetic genes for structurally related (or identical) antibiotics are disseminated in their entirety between microbial species.

Amino Acid Sequence↗
PubMed1992

Antifungal anthracycline antibiotics, spartanamicins A and B from Micromonospora spp.

Spartanamicins A and B, two antifungal antibiotics, were produced by a culture of Micromonospora spp. strain No. MSU-43097 (ATCC 53803), isolated from a potted soil containing asparagus (Asparagus officinalis L.) plants. The antibiotics were isolated from the mycelial cake using organic solvents. The structures of spartanamicins A and B were determined by spectral and chemical means. Spartanamicin B is more active as an antifungal compound than it's analogue, A. The minimum inhibitory concentration for spartanamicin B on Candida albicans and Aspergillus, Cladosporium, Cryptococcus, Rhodotorula and Staphylococcus spp. ranged from 0.2 to 1 microgram/ml. It was not active against Staphylococcus aureus, Escherichia coli and Citrobacter spp. but some strains of S. aureus were sensitive.

Anthracyclines↗
PubMed1995

Rakicidins, new cytotoxic lipopeptides from Micromonospora sp. fermentation, isolation and characterization.

The new cytotoxic agents rakicidins A and B were isolated from cultured broth of a Micromonospora sp. Spectroscopic and amino acid analysis has shown that rakicidin A is a new cyclic lipopeptide, consisting of 4-amino-penta-2,4-dienoic acid, 3-hydroxy-2,4,16-trimethyl-heptadecanoic acid, sarcosine, and 3-hydroxyasparagine. Rakicidin B differs by one methylene group in the lipid side chain. These compounds exhibited cytotoxicity against the M109 cell line.

Animals↗