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PubMed1995

Macquarimicins, microbial metabolites from Micromonospora. I. Discovery, taxonomy, fermentation and biological properties.

A novel series of microbial metabolites were discovered in fermentation broths of two soil isolates. Both cultures were identified as strains of Micromonospora chalcea. Production of the metabolites, named macquarimicins, was monitored by an HPLC assay. A seven-day fermentation yielded 27 mg/liter of macquarimicin A. With MICs of 50 to 100 micrograms/ml, macquarimicin A has only very low activity against strains of Bacteroides and other anaerobes. Macquarimicin B has inhibitory activity against the leukemia cell line P-388.

Animals↗

PubMed1995

Macquarimicins, microbial metabolites from Micromonospora. II. Isolation and structural elucidation.

A novel series of carbocyclic compounds has been isolated from two related Micromonospora cultures. The C-19 and C-22 macquarimicins represent different end products on a similar biosynthetic scheme. 1-D and 2-D homonuclear and heteronuclear NMR experiments allowed assignment of the basic structures of the macquarimicins. An X-ray structure of macquarimicin B suggested the stereochemistry for the series which was not discernible from spectroscopic data alone.

Anti-Bacterial Agents↗

PubMed1995

Gentamicin formation in Micromonospora purpurea: stimulatory effect of ammonium.

The effect of ammonium on the fermentative production of gentamicin in Micromonospora purpurea has been studied using a chemically defined medium. Ammonium chloride concentrations ranging from 20 to 150 mM resulted in a proportional stimulation of growth and antibiotic formation. The use of other ammonium salts exerted a similar effect. Among the products of ammonium assimilation, glutamate and glutamine were able to exert the stimulatory effect. In addition, both amino acids reproduced the stimulation in resting cell systems of this microorganism and this result was not modified by the presence of chloramphenicol, eliminating a possible inductive action as the cause of this effect. The use of a glutamine synthetase inhibitor prevented antibiotic formation. This inhibition was reverted only by glutamine, suggesting that this amino acid was responsible of ammonium stimulation. Glutamine stimulation seems to be due to its ability to produce 2-deoxystreptamine and glucosamine, intermediates of the gentamicin biosynthetic pathway.

Ammonium Chloride↗

PubMed1995

MS-444, a new inhibitor of myosin light chain kinase from Micromonospora sp. KY7123.

A novel compound MS-444 was isolated from the culture broth of a bacterial strain KY7123. The strain was identified as Micromonospora sp. from its morphological and cultural characteristics. The compound inhibited the activity of purified smooth muscle myosin light chain kinase with an IC50 value of 10 microM. The production, isolation, physico-chemical properties and biological activities of MS-444 were described in this paper.

Animals↗

PubMed1996

Antascomicins A, B, C, D and E. Novel FKBP12 binding compounds from a Micromonospora strain.

5 novel ascomycin-like compounds, antascomicins A, B, C, D and E were isolated from a strain of Micromonospora. The antascomicins bind strongly to the FK506-binding protein FKBP12 and antagonize the immunosuppressive activity of FK506 and rapamycin. The strain description, fermentation, structure elucidation and biological activity of these compounds are described.

Animals↗

PubMed1996

Pyrrolosporin A, a new antitumor antibiotic from Micromonospora sp. C39217-R109-7. I. Taxonomy of producing organism, fermentation and biological activity.

Strain C39217-R109-7 (ATCC 53791) is an actinomycete strain isolated from a soil sample collected at Puerto Viejo, Peru. It produces a new antitumor antibiotic, designated pyrrolosporin A. Taxonomic studies on its morphological, cultural and physiological characteristics identified this producing strain as Micromonospora sp. C39217-R109-7. Pyrrolosporin A shows antimicrobial activity against Gram-positive bacteria and it is weakly active against Gram-negative bacteria. Pyrrolosporin A prolongs the life span of mice inoculated with P388 leukemia cells.

Animals↗

PubMed1996

Pyrrolosporin A, a new antitumor antibiotic from Micromonospora sp. C39217-R109-7. II. Isolation, physico-chemical properties, spectroscopic study and X-ray analysis.

Pyrrolosporin A (1) is a new macrolide antitumor antibiotic possessing an unusual spiro-alpha-acyltetronic acid moiety. The antibiotic was isolated from the fermentation broth of Micromonospora sp. by vacuum liquid chromatography, crystallization and reversed phase HPLC (C18). The structure was determined by a combination of NMR, MS, IR, UV, X-ray analysis and degradation studies.

Anti-Bacterial Agents↗

PubMed1997

9-Hydroxycrisamicin A, a new cytotoxic isochromanquinone antibiotic produced by Micromonospora sp. SA246.

9-Hydroxycrisamicin A, a new cytotoxic isochromanquinone antibiotic, was isolated from a soil microorganism SA246 which was identified as Micromonospora sp. The molecular formula of 9-hydroxycrisamicin A was determined as C32H22O13 based on the HRFAB-MS analysis, and the structure was determined by various NMR experiments. 9-Hydroxycrisamicin A showed weak antimicrobial activity against Gram-positive bacteria and strong cytotoxic activity against some human cancer cell lines such as SK-OV-3 (ovarian), HCT15 (colon), SK-MEL-2 (melanoma), A549 (lung), XF498 (central nervous system) with ED50 of 0.47-0.65 microgram/ml.

Anti-Bacterial Agents↗

PubMed1997

Thiocoraline, a new depsipeptide with antitumor activity produced by a marine Micromonospora. I. Taxonomy, fermentation, isolation, and biological activities.

A novel bioactive depsipeptide, thiocoraline, was isolated from the mycelial cake of a marine actinomycete strain L-13-ACM2-092. Based on morphological, cultural, physiological, and chemical characteristics, strain L-13-ACM2-092 was ascribed to the genus Micromonospora. Thiocoraline showed a potent cytotoxic activity against P-388, A-549 and MEL-28 cell lines, and also a strong antimicrobial activity against Gram-positive microorganisms. This compound binds to supercoiled DNA and inhibits RNA synthesis.

Animals↗

PubMed1997

YM-47515, a novel isonitrile antibiotic from Micromonospora echinospora subsp. echinospora.

During the course of our screening for new antibiotics, Micromonospora echinospora subsp. echinospora Y-03559J was found to produce a novel isonitrile compound, YM-47515 (1) along with a probable degradation product 2. The structure of 1 was assigned by spectroscopic analysis including 2D NMR and IR experiments. The relative stereochemistry of 1 was also proposed by comparison of spectral data with those of a closely related compound aerocyanidin (3). YM-47515 (1) showed promising antimicrobial activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA).

Anti-Bacterial Agents↗

PubMed1998

Fermentation studies of rustmicin production by a Micromonospora sp.

The antifungal antibiotic rustmicin was detected in the fermentation broth of the actinomycete MA 7094 as a specific inhibitor of sphingolipid biosynthesis in Candida albicans and as a potent fungicidal agent against Cryptococcus neoformans. Taxonomic characterization by both classical means and PCR fingerprinting supported the assignment of the producing culture to the genus Micromonospora. Fermentation medium optimization studies showed that the concentration of tomato paste in the medium was critical to increased production of rustmicin by MA 7094. The stimulatory effect of tomato paste in the medium on rustmicin production appeared to be related to the maintenance of pH at or below a value of 6.0. Addition of the antifoam agent P-2000 to the fermentation was found to dramatically reduce the rustmicin titer, while substitution of another antifoam agent, UCON-LB625, resulted in a 100% increase in the amount of rustmicin detected. After fermentation optimization studies and the generation of a non-sporulating mutant of MA 7094, the rustmicin titer was increased from an initial titer of 10mg/liter to 145 mg/liter.

Antifoaming Agents↗

PubMed2000

Arisostatins A and B, new members of tetrocarcin class of antibiotics from Micromonospora sp. TP-A0316. I. Taxonomy, fermentation, isolation and biological properties.

Arisostatins A and B, new members of tetrocarcin class of antibiotics were isolated from the culture broth of an actinomycete strain. The producing strain, TP-A0316, was identified as Micromonospora sp. Arisostatins were obtained from the culture fluid by solvent extraction and chromatographic purification. They showed antibiotic activity against Gram-positive bacteria and antitumor activity.

Aminoglycosides↗

PubMed2000

SB-219383, a novel tyrosyl tRNA synthetase inhibitor from a Micromonospora sp. I. Fermentation, isolation and properties.

A novel, potent and selective inhibitor of bacterial tyrosyl tRNA synthetase, designated SB-219383 has been isolated from Micromonospora sp. NCIMB 40684. The fermentation, isolation and some properties are described, whilst the structure determination is described in the succeeding paper). SB-219383 showed competitive, inhibitory activity against a Staphylococcus tyrosyl tRNA synthetase, with an IC50 of <1 nM, and exhibited weak in vitro activity against some Streptococcus sp.

Bridged Bicyclo Compounds, Heterocyclic↗

PubMed2000

SB-219383, a novel tyrosyl tRNA synthetase inhibitor from a Micromonospora sp. II. Structure determination.

A novel tyrosyl tRNA synthetase inhibitor, SB-219383, has been isolated from a Micromonospora sp. The structure of SB-219383 has been elucidated by a combination of derivatisation, spectroscopic and other analytical techniques and found to be N-(L-tyrosyl)-2-amino[1(S*),3(S*),4(S*),5(R*),8(R*)-2,4,5,8-tetrahydroxy -7-oxa-2-azabicyclo[3.2.1]oct-3-y1]acetic acid (1).

Bridged Bicyclo Compounds, Heterocyclic↗

PubMed2000

IB-96212, a novel cytotoxic macrolide produced by a marine Micromonospora. I. Taxonomy, fermentation, isolation and biological activities.

A novel bioactive macrolide, IB-96212 has been isolated from the fermentation broth of a marine actinomycete, L-25-ES25-008. The strain belongs to the genus Micromonospora. The macrolide showed a very strong cytotoxic activity against P-388, and lower but significant activity against A-549, HT-29, and MEL-28 cell lines. We describe the isolation, taxonomy and fermentation of the producing strain as well as the isolation of IB-96212.

Anti-Bacterial Agents↗

PubMed2000

IB-96212, a novel cytotoxic macrolide produced by a marine Micromonospora. II. Physico-chemical properties and structure determination.

IB-96212, is a new member of spiroketal containing macrolide class of fermentation-derived natural products isolated from mycelial extracts of Micromonospora sp. The structure consists of a new aglycone which possesses a 26-membered macrolide ring system and of one deoxy sugar identified as L-rhodinose, this structure represents the first reported spiroketal macrolide natural product related to other macrolides, such as oligomycins, dunaimycins, citovaricin, rutamycin and ossamycin.

Anti-Bacterial Agents↗

PubMed2000

4'-N-methyl-5'-hydroxystaurosporine and 5'-hydroxystaurosporine, new indolocarbazole alkaloids from a marine Micromonospora sp. strain.

Two new indolocarbazole alkaloids, 4'-N-methyl-5'-hydroxystaurosporine (2) and 5'-hydroxystaurosporine (3), were isolated together with the known staurosporine (1) from the culture broth of a marine Micromonospora sp. (strain L-31-CLCO-002). The fermentation, structural data and cytotoxic activities of these compounds against various tumor cell lines are given.

Alkaloids↗

PubMed2003

R176502, a new bafilolide metabolite with potent antiproliferative activity from a novel Micromonospora species.

During the course of a screening program intended to identify new antiproliferative agents, a new bafilolide metabolite was discovered. R176502 (1) was isolated from the liquid fermentation cultures of a novel Micromonospora species found in African river bottom sediment. It was purified from ethyl acetate extracts using a series of countercurrent chromatographic steps. The structure was determined using 1- and 2-D NMR experiments. Three previously described bafilomycins (bafilomycins A1 (2), B1 (3), and B2 (4)) were also isolated (from other microbial strains). R176502 exhibited potency for inhibition of tumor cell proliferation in the nM range of concentrations.

Antineoplastic Agents↗