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At least 19 recordsLinked to original sources
PubMed1978

[Directed isolation of Micromonospora generic cultures on a selective medium with gentamycin].

The results of using selective media with gentamicin for directed isolation of Micromonospora are presented. It was shown that the use of the selective media with gentamicin for isolation of actinomycetes from soils of usual humidity levels markedly increased the frequency of Micronomonospora detection. The use of the selective media with gentamicin for plating out silt substrates containing mainly Micromonospora had practically no effect on the increase in the number of the Micromonospora cultures grown. The number of antibiotic-producing Micromonospora isolated on the media with gentamicin was 3 times higher than that on the control media. The use of the selective media with gentamicin provided directed isolation of Micromonospora.

Culture Media↗
PubMed2026

Secondary metabolite profiling of rare Micromonospora spp. from cold desert of NW Himalayas via multi-omics analysis.

INTRODUCTION: The genus Micromonospora is a prolific producer of specialized metabolites with pharmacological and agronomic relevance. Natural products derived from the genus Micromonospora have a distinctive chemical diversity and enormous therapeutic potential, thus represent a potential source for drugs and drug leads. OBJECTIVE: To explore the biosynthetic potential of four Micromonospora strains isolated from cold desert of NW Himalayas through genome mining and to correlate predicted biosynthetic gene clusters with chemical features detected by untargeted LC-HRMS metabolomics. METHOD: High-quality genomes were annotated for BGCs and matched against untargeted LC-HRMS features (peak picking, alignment, and annotation to chemical classes). Each isolate was grown in triplicate, and fermented broth was pooled for further metabolomic studies. RESULTS: By integrating genomic and metabolomic approaches, specialized biosynthetic gene clusters and strain-based putative metabolite classes were identified. LRS1 showed elevated xanthines (RiPP/siderophore), LRS3 had phenolic glycosides (hybrid PKS/NRPS), LRS4 showed 70-fold hydroxycinnamate enrichment (Type II PKS), and LRS5 displayed p-benzoquinone enrichment (Type III PKS). The metabolite profile of each strain aligned with its predicted biosynthetic gene cluster composition. CONCLUSION: Under a single growth regime, each Micromonospora strain exhibits a distinct metabolomic profile. This metabologenomics workflow can be further explored to isolate specialized metabolites with potential therapeutic and agricultural value.

Micromonospora↗
PubMed1978

[Directed isolation of Micromonospora generic cultures from moist soils and silts].

The data on the study of various soils and substrates for isolation of Micromonospora from them are presented. It was shown that Micromonospora predominated in moist soils and especially in such substrates as silts where their content with respect to the all actinomycetous isolates amounted to 88.9 per cent. In the silts the content of Micromonospora amounted to 66.6--83 per cent, in the sopromely its content was 66 per cent, while in the ordinary non-moist soil its content was from 6 to 11 per cent. Predominance of Micromonospora in silts and moist soils makes its directed search possible.

Asia, Eastern↗
PubMed1978

[Data on the conditions for the prolonged storage of Micromonospora generic cultures].

Data on studying various conditions for prolonged storage of Micromonospora are presented. It was shown that Micromonospora were satisfactorily stored under conditions of all maintenance methods used. The optimal methods were the following: storage of Micromonospora on agarized media under a layer of vaseline oil, storage of Micromonospora in the form of a mature submerged culture on liquid media optimal for its growth and development. Stimulating effect of low temperature on the spore germination was shown.

Culture Media↗
PubMed1979

[Formation of broad-spectrum antibiotics by cultures of the genus Micromonospora].

Data on the study of antibiotic production by the representatives of Micromonospora and the use of ion exchange resins for intensification of screening antibiotic-producing organisms among Micromonospora are presented. It was found that out of 172 strains of Micromonospora tested 92 (53.5 per cent) cultures produced antibiotics, 18 of which were active against gramnegative bacteria. The use of carboxylic ion exchange resins at early microbiological stages of the screening provided an increase in the frequency of finding broad spectrum antibiotics from 10.4 to 19.7 per cent.

Adsorption↗
PubMed1978

Production of gentamicins by Micromonospora purpurea.

The natural medium contained the following ingredients (g/l): glucose 8.0, or black strap molasses (treated with 0.2--0.3 g/l EDTA) 12.0, fodder yeast (50.0% total nitrogen) 2.0, or folder yeast (40.0% total nitrogen) 6.0, or yeast extract 8.0, or tryptone 8.0, and CaCO3 1.0. Treated black strap molasses with EDTA and fodder yeast proved to be effective in the fermentative production of gentamicins. The most suitable chelating agent was EDTA in the form of disodium for the treatment of Komombo molasses in a concentration of 0.2--0.3 g/l, while potassium ferrocyanide and methylene blue had depressing effects on the production of gentamicins. The most effective carbon source, present in Egyptian black strap molasses, was glucose. Addition of glucose to the medium was preferable at the beginning of the fermentation process. Trace elements present in molasses were very essential for the microbial growth and biosynthesis of gentamicins as proved when molasses ash was added to the natural medium. Organic nitrogen sources were more suitable than inorganic nitrogen sources for the production of gentamicins by Micromonospora purpurea. The microorganism utilized the synthetic medium, but the antibiotic yields were less than those produced in the natural medium. The synthetic medium exhibited stimulatory effects of certain amino acids, organic acids, vitamins, and purine and pyrimidine bases on the fermentative production of gentamicins. Therefore, the ingredients increasing yields of gentamicins were mainly phenylalanine, iso-leucine, lysine, methionine, leucine, arginine, glycine, beta-alanine, cystine, tryptophan, malic acid, maleic acid, cobalamin, folic acid, riboflavin, vitamin B1, vitamin B6, biotin, nicotinamide, uracil, adenine, guanine, and adenosine. Trace elements (Co, Mo, Fe, Cu, Zn, and Mn) exhibited their important role on the biosynthesis and production of gentamicins by Micromonospora purpurea.

Carbon↗
PubMed1976

A new actinomycin complex produced by a Micromonospora species: fermentation, isolation, and characterization.

A species of Micromonospora, Micromonospora floridensis NRRL 8020, has been found to produce an actinomycin complex consisting of at least 25 active components. After solvent extraction of the complex, separation of the individual components was carried out by preparative thin-layer chromatography. Hydrolysis and subsequent electrophoretic and chromatographic identification of the amino acid content of each of the isolated components have shown differences from known actinomycins, and the probability exists that these contain a number of amino or imino acids not previously found in other members of this group of antibiotics.

Amino Acids↗
PubMed1978

Mode of action of gentamicin antibiotics produced by Micromonospora purpurea.

Gentamicin antibiotics were produced fermentatively by Micromonospora purpurea. They were separated into gentamicin C1, C1a and C2 by paper chromatographic technique, using chloroform, methanol, and 17.0% of NH4OH (2: 1: 1 v/v) as developing solvent. The different antibiotics showed variable antimicrobial activities. The gentamicin antibiotics inhibited the biosynthesis of DNA and RNA of the proteins, present in the cells of Staphylococcus aureus.

Bacteria↗
PubMed1978

Antibiotic biosynthesis by cofermentation of blocked mutants of two Micromonospora species.

Two aminocyclitol-negative Micromonospora mutants representing two different species, M. purpurea and M. inyoensis, and blocked at different steps in the biosynthetic pathway were paired and cofermented for the synthesis of antibiotics. The two blocked mutants were incapable of producing antibiotics alone except when 2-deoxystreptamine was added. When combined they produced gentamicins A, X(2), C(1a), and C(2b), which all have an amino group at the 2' position, and gentamicin B, which has a hydroxyl group at this position instead.

Anti-Bacterial Agents↗
PubMed1977

Mannitol oxidation in two Micromonospora isolates and in representative species of other actinomycetes.

Mannitol kinase and mannitol-1-phosphate dehydrogenase activities were detected in two Micromonospora isolates. The presence of these enzyme activities indicates that mannitol is catabolized first to mannitol-1-phosphate and then to fructose-6-phosphate. Mannitol-oxidizing enzymes were also surveyed in representative species of four other genera of actinomycetes. Mannitol-1-phosphate dehydrogenase was detected in cell-free extracts of Streptomyces lactamdurans. In contrast, cell-free extracts of Mycobacterium smegmatis, Nocardia erythrophila, Streptomyces lavendulae, and Actinoplanes missouriensis contained mannitol dehydrogenase activity but no detectable mannitol-1-phosphate dehydrogenase activity. The mannitol dehydrogenase activities in the latter species support the operation of a pathway for catabolism of mannitol that involves the oxidation of mannitol to fructose, followed by phosphorylation to fructose-6-phosphate.

Actinomycetales↗
PubMed1978

Characteristics of bacteriophages for Micromonospora purpurea.

Chemical and physical stabilities of bacteriophages øUW 21 and øUW 51 infecting Micromonospora purpurea ATCC 15835 were examined. Both phages were stable over the pH range of 5 to 8 and to heating at temperatures up to 50 degrees C and especially stable in buffer containing magnesium ion. Exposure to 1 M Ca(NO3)2 inactivated both phages, and phage øUW 51 was also susceptible to 1 M CaCl2, 0.1 M tris(hydroxymethyl)aminomethane, and 0.3% H2O2. Phage plating efficiency was highest on the cultures at logarithmic phase and sometimes much influenced by host growth. Phage øUW 51 has a latent period of 2 h at 34 degrees C and a burst size between 35 and 40. The latent period for phage øUW 21 is about 12 h, and the burst size is smaller than 30.

Bacteriophages↗
PubMed1977

Fortimicin A production by Micromonospora olivoasterospora in a chemically defined medium.

A chemically defined medium was devised in order to study the requirements for fortimicin A production by Micromonospora olivoasterospora KY 11515. Soluble starch was the best carbon source; NH4Cl and NH4NO3 were suitable nitrogen sources both for the growth and fortimicin production. Amino acids such as L-asparagine, L-aspartic acid and L-glutamic acid showed some stimulatory effects on both growth and antibiotic production of M. olivoasterospora while L-serine stimulated only antibiotic production and L-citrulline only the growth. K2HPO4, MgSO4.7H2O and CaCO3 were essential especially for the antibiotic production. The most important finding was that vitamin B12, cobalt and nickel showed marked stimulatory effects on fortimicin A production.

Amino Acids↗
PubMed1977

Mutational biosynthesis by idiotrophs of Micromonospora purpurea. I. Conversion of aminocyclitols to new aminoglycoside antibiotics.

By mutation and strain improvement techniques idiotrophs of Micromonospora purpurea, the gentamicin-producing organism, were obtained which require an exogenous source of 2-deoxystreptamine in order to produce gentamicin. Streptamine incorporation afforded a mixture of 2-hydroxygentamicin C as a complex of essentially the C1 and C2 components whereas 2-deoxystreptamine when incorporated by the same idiotroph afforded the same mixture of C1, C2 and C1a gentamicins as the parent (m1) organism. The 2-hydroxygentamicin C complex exhibited broad-spectrum antibiotic activity with an in vitro potency less than that for the gentamicin C complex, but with greater activity against selected gentamicin C resistant organisms. The LD 50 (i.v.) in mice of the 2-hydroxygentamicin C complex indicated that it had approximately half the toxicity of the gentamicin C complex. 2, 5-Dideoxystreptamine affordeda C1, C2, and C1a mixture of 5-deoxygentamicins, which also had broad spectrum activity, and exhibited improved activity against several gentamicin-acetylating strains of resistant bacteria. The LD50 (i.v.) in mice of the 5-deoxygentamicin C complex indicated that it was about 2.5 times more toxic than the gentamicin C complex. Two derivatives of 2,5-dideoxystreptamine afforded the same mixture of 5-deoxygentamicins. 2-Epistreptamine upon supplementation to a broth containing growing cultures of these idiotrophs also produced antibiotic.

Amino Sugars↗
PubMed1977

Metabolites of gentamicin-producing Micromonospora species I. Isolation and identification of metabolites.

From the cultural broth of a Micromonospora species 25 aminocyclitol antibiotics were isolated by repeated ion-exchange chromatographic processes. The main components of the metabolites were identified as gentamicin C1, C2, and C1a. The other previously reported gentamicin type antibiotics and some other degradation products including gentamicin A, B, B1, X2, sisomicin, garamine, gentamines etc., were identified by chemical, PMR, and mass spectroscopic studies. Besides these, seven new gentamicin type antibiotics were isolated and characterized.

Bacteria↗
PubMed1977

Mutational biosynthesis by idiotrophs of Micromonospora purpurea. II. Conversion of non-amino containing cyclitols to aminoglycoside antibiotics.

A mutant of Micromonospora purpurea, which produces the gentamicin complex only when 2-deoxystreptamine is added to the fermentation medium, produces a new antibiotic complex, 2-hydroxygentamicin, when streptamine or 2,4,6/3,5-pentahydroxycyclohexanone is added to the fermentation medium. This mutant also produces the gentamicin complex when 2,4/3,5-tetrahydroxycyclohexanone is added to the fermentation medium. The C1 and C2 components of 2-hydroxygentamicin have broad spectrum in vitro antibacterial activity similar to the gentamicin C1 and C2 components, but with greater activity against some gentamicin-resistant strains.

Bacteria↗
PubMed1978

Macrolide antibiotics M-4365 produced by Micromonospora. III. In vitro antimicrobial activity of antibiotic M-4365G2 (de-epoxy rosamicin).

Antibiotic M-4365G2 (de-epoxy rosamicin) produced by Micromonospora capillata MCRL 0940 is a new basic 16-membered macrolide antibiotic with activity equal to or superior to erythromycin and josamycin against Gram-positive bacteria. Of interest are the high degree of activity against Gram-negative bacilli and mycoplasmas, and striking inhibitory effects against indole-producing Proteus spp. Bactericidal activity of M-4365G2 is also to be noticed.

Aminoglycosides↗
PubMed1977

[Effect of cobalt on the growth of a Micromonospora purpurea var. violacea 1935 culture and on the biosynthesis of gentamincin].

The effect of cobalt on growth of Micromonospora purpurea var. violacea 1935 and biosynthess of gentamicin in complex soy-bean meal or "synthetic" gelatin medium was studied. In optimal concentrations cobalt increased the activity level of the culture fluid almost 6 times in both media having practically no effect on the amount of the mycelium formed. Addition of cobalt to the medium resulted in retardation of the organism growth and consumption of the nutrients. Stimulation of gentamicin biosynthesis by cobalt was inversely proportional to the time of the trace element addition. The cobalt effect depended on the aeration conditions, inorganic phosphorus level in the medium and physiological condition of the mycelium.

Aerobiosis↗