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PubMed1999

Gentamicin-resistance determinants confer background-dependent hygromycin B resistance.

Micromonospora strains that produce aminoglycoside antibiotics have a high level of resistance to their own products and to structurally similar antibiotics with a 4,6-disubstituted deoxystreptamine aminocyclitol component such as neomycin, kanamycin, or gentamicin, but these strains remain susceptible to other aminoglycosides such as neomycin and apramycin, in which the aminocyclitol component has different types of substitutions. Therefore, it was surprising that the aminoglycoside-producing Micromonospora strains examined here also showed high-level resistance to hygromycin B, in spite of the fact that this compound has a structurally different aminocyclitol component and a mode of antibacterial action that was also shown to differ somewhat from the mode of action of gentamicin-type antibiotics. When the resistance genes sgm and grm were cloned in Streptomyces lividans and E. coli, they conferred resistance to the expected aminoglycoside compounds but not to hygromycin B. In contrast, introduction of the same resistance genes to M. melanosporea produced resistance to hygromycin B as well. Such an apparent strain dependence in the expression of hygromycin B resistance was also observed with other genes from related genera that are also responsible for aminoglycoside resistance due to methylation of 16S rRNA: of these genes, only kgm assisted expression of hygromycin B resistance and only in the background of M. melanosporea. A possible mechanism for the background dependent of hygromycin B resistance is discussed.

Anti-Bacterial Agents↗

PubMed1993

Characterization of two different types of resistance genes among producers of fortimicin-group antibiotics.

Fortimicin-A (FTM-A; astromicin)-resistance genes (fmr genes) isolated from six producers of the FTM-group of antibiotics were analysed. These genes could be classified into two types by the resistance profiles to aminoglycoside antibiotics and by their DNA homologies. Three genes, fmrT from the istamycin producer Streptomyces tenjimariensis ATCC 31603, fmrS from the sannamycin producer Streptomyces sannanensis IFO 14239 and fmrH from the sporaricin producer Saccharopolyspora hirsuta ATCC 20501, conferred resistance to FTM-A, kanamycin (Km) and neomycin B (Nm-B), but not to gentamicin (Gm). The other three genes, fmrO from the FTM-A producer Micromonospora olivasterospora ATCC 21819, fmrM from the antibiotic SF-2052 producer Micromonospora sp. SF-2098 (ATCC 31580) and fmrD from the dactimicin producer Dactylosporangium matsuzakiense ATCC 31570, conferred resistance to FTM-A, Km and Gm, but not to Nm-B. No DNA homology was detected between the two types of the resistance genes in Southern-blot analysis. The present results revealed that, in spite of the similarity of their biosynthesis genes, there are at least two different types of resistance genes among the FTM-group antibiotic producers.

Actinomycetales↗

PubMed2002

Diversity of antifungal actinomycetes in various vegetative soils of Korea.

Diversity of actinomycetes and their antifungal activities against some plant pathogenic fungi were examined in various vegetative soils from 14 different sites in the western part of Korea. Actinomycete counts ranged from 1.17 x 10(6) to 4.20 x 10(6) cfu x g(-1) dried soil. A total of 1510 actinomycetes were isolated from the soil samples. Streptomyces was predominant in soils with a pH range of 5.1-6.5, 9.1-13.0% moisture, and 9.1-11.0% organic matter. Most Micromonospora, Dactylosporangium, and Streptosporangium were distributed in soils with pH 4.0-5.0, 2.0-9.0% moisture, and 4.0-7.0% organic matter. Actinomadura and nocardioform actinomycetes were abundant in soils with pH 4.0-5.0 and 13.1-20.0% moisture and with 9.1-11.0 and 4.0-7.0% organic matter, respectively. Populations of Streptomyces were predominant in all the soils, but were highest in grassland and lowest in mountain-forest soils. Micromonospora was most abundant in pepper-field soil and nocardioform actinomycetes were highest in rice paddy field soil. Dactylosporangium was predominant in lake-mud sediments and pepper-field soil, Streptosporangium in lake-mud sediments, and Actinomadura in mountain-forest soil. Antifungal actinomycetes were abundant in orchard soil and lake mud. More than 50% of antifungal isolates from most soils were classified as genus Streptomyces. Actinomycete isolates that showed strong antifungal activity against Alternaria mali, Colletotrichum gloeosporioides, Fusarium oxysporum f.sp. cucumerinum, and Rhizoctonia solani were predominant in pepper-field soils, whereas those against Magnaporthe grisea and Phytophthora capsici were abundant in radish-field soils.

Actinomycetales↗

PubMed1976

Studies on juvenimicin, a new antibiotic. I. Taxonomy, fermentation and antimicrobial properties.

An actinomycete, strain No. T-1124, was found to produce new macrolide antibiotics, juvenimicins. Based on the results of taxonomic studies, the strain was considered to be a new variety of micromonospora chalcea and the name Micromonospora chalcea var. izumensis is proposed. This strain also produced everninomicin. The production of juvenimicins was stimulated by addition of ferrous sulfate and magnesium sulfate in the fermentation medium. Among juvenimicins, juvenimicin A3 exhibited the most potent antimicrobial activities against gram-positive bacteria and furthermore was active against gram-negative bacteria.

Anti-Bacterial Agents↗

PubMedDate not supplied

[Actinomycete complexes in the rhizosphere of winter rye on soddy podzolic soil].

The structure of actinomycete complexes in the rhizosphere of winter rye (Secale cereale L.) varieties originating from different ecosystems and geographical zones was studied in field experiments on soddy podzolic soil. In addition to streptomycetes, the complexes studied contained actinomycetes of the genera Micromonospora and Streptosporangium, represented at high occurrence and comparable abundance rates. The rhizosphere of most of the studied rye varieties was dominated by micromonosporas. The antifungal potential of mycelial prokaryotes associated with winter rye was assessed. The taxonomic and functional structure of actinomycete complexes was shown to be similar in rye varieties originating from the nonchernozem zone of Russia. However, the actinomycete complex proved to be much different in the rye variety that developed in the steppe zone of the lower Volga region.

Actinobacteria↗

PubMed1989

[Studies on actinomycete flora and resources in the plateau lakes in Yunnan].

During the period of 1983 to 1987 mud and water samples were collected from 12 larger lakes on the Yunnan Plateau. The actinomycetes in both sediment and water samples were investigated. Strains producing metabolites were screened by various procedures. The results are as follow: 1. The number and composition of actinomycetes in a lake were found to have relation to the physical and chemical features of the water-body. On the basis of the number and generic diversity of actinomycetes, lakes were thus divided into four groups. 2. Micromonospora occupied a notable domonance in benthic samples taken from all 12 lakes. This is a conspicuous characteristics of actinomycete flora in these lakes. 3. The population of actinomycetes in Lakes Qilu, Yilong and Datun ranges from 2991 to 3542 X 10(3)/g dry wt. of mud. 4. Strains of Actinomadura, Microtetraspora, Micropolyspora, Saccharomonospora and Saccharopolyspora were isolated. These genera were not previously reported in similar studies abroad. In addition, five species were considered to be new to science: Micromonospora phaeovirida Jiang et Xu, 1985 Saccharomonospora yunnanensis Jiang et Xu, 1985 Microtetraspora flavorosea Jiang et Xu, 1986 Actinomadura chenghaiensis Jiang et Xu, 1986 Actinomadura viridoflava Jiang et Xu, 1986 5. Studies indicate that actinomycetes possibly play an important role in the decomposition of chitin, cellulose and some toxic substances in lakes. 6. As freshwater resources, actinomycetes produce various useful metabolites such as fibrinolysine, and milk-clotting enzyme.

Actinomycetaceae↗

PubMedDate not supplied

[Taxonomic position of cultures of the family Micromonosporaceae].

The paper describes cultures that can be assigned to the genus Micropolyspora according to such properties as the presence of aerial mycelium, catenae of spores and galactose in the composition of sugars in the cell wall. However, the cultures contain xylose in the cell wall and therefore are related to the genus Micromonospora. These findings as well as the atypical proportion between DAPA and its isomers suggest that the cultures occupy an intermediate position between the genus Micromonospora and the genus Micropolyspora.

Micromonospora↗

PubMed1998

Utilization of quinate and p-hydroxybenzoate by actinomycetes: key enzymes and taxonomic relevance.

474 strains of the actinomycete genera Streptomyces (including species of the former genera Chainia and Streptoverticillium), Pseudonocardia and Micromonospora were examined for their ability to degrade quinate (Q) and p-hydroxybenzoate (pHB); selected strains were also tested for their capacity to catabolize benzoate (B). Whereas in the case of Q (5-10 g/l of a mineral salts agar medium) the growth response signalizes assimilation, pHB has to be supplied in lower concentration (routinely 0.3 g/l together with small amounts of peptone and yeast extract in liquid broth), and its degradation has to be determined spectrophotometrically. 27% of the streptomycete strains were able to grow with Q, and 57% with pHB. The three strains of "Chainia" that were tested metabolized Q and pHB, but none of the fourty species of "Streptoverticillium" showed this ability. 80% of the 30 strains of Psn. autotrophica grew with Q, and 100% degraded pHB and B. Two of the five Micromonospora strains gave a positive response with pHB, but not with Q.-Toluene treated cells (preincubated with Q, pHB or B, respectively) gave a positive Rothera reaction with protocatechuate or catechol respectively, thus demonstrating that these organisms employed the beta-ketoadipate pathway (orthofission) for the degradation of Q, pHB and B. The assay of five relevant enzymes in cell-free extracts of nine selected organisms showed that in nocardioform actinomycetes (Pseudonocardia, Rhodococcus) all enzymes of the protocatechuate branch of the ketoadipate pathway seem to be induced by beta-ketoadipate as demonstrated here for protocatechuate-3,4-dioxygenase. In contrast, in Streptomyces this enzyme appears to be induced by its substrate, protocatechuate, whereas the regulation of the other enzymes of this pathway remains to be elucidated.

2,4-Dichlorophenoxyacetic Acid↗

PubMed1985

[Leukaemomycin-blocked mutants of Streptomyces griseus and their pigments. III. 11-Desoxydaunomycinone derivatives from the mutant ZIMET 43699/G44].

The isolation and identification of several anthracyclinones (designated as G44-K4/5, G44-G1, G44-G2) and anthracyclines (G44-A, B, C, D, E, F, G) produced by the mutant strain IMET JA 3933/G44 of the daunomycin-producing Streptomyces griseus strain IMET JA 3933 are described. G44-K4/5 was found to be identical with 7,11-dideoxy-13-dihydrodaunomycinone previously isolated from a mutant strain of Streptomyces coeruleorubidus. Compound G44-G1 was identified as 11-deoxydaunomycinone, the aglycone of the antibiotic 11-deoxydaunomycin. G44-G2 was found to be a stereoisomer of G44-G1. The NMR and CD spectral data suggest strongly that the compound is 7-epi-11-deoxydaunomycinone. Of the 7 isolated G44-glycosides only the major component G44-B could be identified. Comparison with an authentic sample revealed that this compound is 11-deoxydaunomycin which had previously been isolated from cultures of Streptomyces peucetius var. aureus and Micromonospora peucetica. As reported for S. coeruleorubidus, S. peucetius var. aureus, and Micromonospora peucetica the 11-deoxydaunomycinone derivatives described in this paper were isolated from the fermentation broth of a mutant of a daunomycin-producing wild type strain. This suggest that in general the accumulation of 11-deoxydaunomycinone derivatives may be the result of a block of C11-hydroxylation in the normal biosynthetic pathway of daunomycin and its analogues.

Antibiotics, Antineoplastic↗

PubMed2006

Actinomycetes in rice straw decomposition.

Actinomycetes are well known as lignocellulose decomposers. Forty-two cellulolytic actinomycete isolates have been recovered from soil. Those were identified to the genus level as: Streptomyces (26 isolates), Nocardiopsis (5 isolates), Micromonospora (4 isolates), Nocardioides (4 isolates) in addition to three isolates tentatively identified as Nocardia, Kibdelosporangium and Saccharomonospora. These actinomycetes were examined for their cellulolytic activity using filter paper strips and rice straw pieces. Four isolates of the four genera Kibdelosporangium, Micromonospora, Streptomyces and Nocardioides were able to efficiently degrade rice straw pieces in minimal medium causing significant weight loss between 50 and 61%. Application of this knowledge may improve the management of waste rice straw.

Actinobacteria↗

PubMed1997

Bacterial degradation of natural rubber: a privilege of actinomycetes?

Using natural rubber latex as the sole source of carbon and energy 50 rubber-degrading bacteria were isolated. Out of those 50 isolates, 33 were identified as Streptomyces species and 8 as Micromonospora species. Screening of 1220 bacteria obtained from different culture collections revealed 46 additional rubber-degrading bacteria (Streptomyces 31 strains, Micromonospora 5, Actinoplanes 3, Nocardia 2, Dactylosporangium 1, Actinomadura 1, unidentified 3). All rubber-degrading isolates were identified as members of the actinomycetes, a large group of mycelium-forming Gram-positive bacteria. Interestingly no Gram-negative bacterium could be isolated. In most strains expression of extracellular rubber-degrading enzymes was repressed by glucose and/or succinate. The reduction of the average molecular mass of solution-cast films of natural rubber from 640000 to 25000 in liquid culture upon bacterial growth indicates the participation of an endo-cleavage mechanism of degradation.

Actinomycetales↗

PubMed1998

Verrucosispora gifhornensis gen. nov., sp. nov., a new member of the actinobacterial family Micromonosporaceae.

A Gram-positive, aerobic, spore-forming actinomycete strain, HR1-2T, was isolated from a peat bog near Gifhorn, Lower Saxony, Germany. Comparative analysis of the 16S rDNA sequence indicated that HR1-2T was phylogenetically related to members of the family Micromonosporaceae, branching adjacent to Spirilliplanes yamanashiensis, Couchioplanes caeruleus, Catenuloplanes japonicus and members of the genus Micromonospora. The affiliation to the family was supported by the presence of family-specific 16S rDNA signature nucleotides, DNA G + C content of 70 mol%, peptidoglycan of type A1 gamma' (directly crossed-linked, presence of glycine, alanine, glutamic acid and mesodiaminopimelic acid in the peptide side-chain), menaquinone MK-9(H4) as the major respiratory lipoquinone, polar lipid composition PII (phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylserine and phosphatidylinositolmannosides) and a glycolyl type of muramic acid. It differed from genera of the family by the lack of arabinose in whole-cell sugars and a unique nucleotide signature stretch between positions 1132 and 1143 (Escherichia coli numbering), 5' CAAUUCGGUUG 3'. Morphologically strain HR1-2T resembles Micromonospora species but can be distinguished from them by the lack of arabinose in whole-cell sugars, the presence of 10-methyl C17:0 fatty acids and a distinct 16S rDNA sequence. Based on the unique combination of morphological, chemotaxonomic and phylogenetic properties a new genus, Verrucosispora gen. nov., is proposed. The type species of this genus is Verrucosispora gifhornensis sp. nov., and the type strain of V. gifhornensis is strain HR1-2T (= DSM 44337T).

Anti-Bacterial Agents↗

PubMed2000

Effect of pretreatment of rubber material on its biodegradability by various rubber degrading bacteria.

The effect of pretreatment of several cis-1,4-polyisoprene containing rubbers on their biodegradability was examined. Tests were carried out with six recently isolated and characterized rubber degrading bacteria belonging to the genera Gordonia (strains Kb2, Kd2 and VH2), Mycobacterium, Micromonospora and Pseudomonas. All strains were able to use natural rubber (NR) as well as NR latex gloves as sole carbon source. Extraction of NR latex gloves by organic solvents resulted in an enhancement of growth for three of the selected strains. On the other hand, growth of Gordonia sp. (strain Kb2 and Kd2), Mycobacterium fortuitum NF4 and Micromonospora aurantiaca W2b on synthetic cis-1,4-polyisoprene did only occur after removal of the antioxidants, that are usually added during manufacture to prevent aging of the materials. Detailed degradation studies performed with Gordonia sp. Kb2 revealed an enhanced mineralization of pretreated NR latex gloves and mineralization of purified natural rubber (NR), indicating the actual mineralization of cis-1,4-polyisoprene rubber constituent even after removal of non-rubber constituent that may act as co-metabolic substrate and support microbial growth. Further analysis by scanning electron microscopy (SEM) clearly demonstrated the enhanced colonization efficiency of these bacteria towards pretreated NR latex gloves. Colonization was additionally visualized by staining of overgrown NR latex gloves with Schiff's reagent, and the purple color produced in the area of degradation was an evidence for the accumulation of aldehydes containing oligomers. Further enhancement of latex gloves degradation could be achieved after successive replacement of mineral salts medium during cultivation. Thereby, a rapid disintegration of untreated NR latex gloves material was accomplished by Gordonia sp. strain VH2.

Actinomycetales↗

PubMed1992

Cloning and analysis of a gene (sms13) encoding sannamycin B-glycyltransferase from Streptomyces sannanensis and its distribution among actinomycetes.

A gene encoding sannamycin B-glycyltransferase (sms13) of Streptomyces sannanensis IFO 14239 was identified by cloning and complementation of S. sannanensis mutant SN13 which is blocked at the interconversion of sannamycins B and A. The cloned DNA fragment also permitted the conversion of fortimicin B to A both in S. sannanensis SN13 and Streptomyces lividans TK23. DNA sequences similar to sms13 were detected in all five producers of the fortimicin-group antibiotics, Micromonospora olivasterospora ATCC 21819 (fortimicin-producer), Micromonospora sp. strain SF-2098 ATCC 31580 (SF-2052), Dactylosporangium matsuzakiense ATCC 31570 (dactimicin), Streptomyces tenjimariensis ATCC 31603 (istamycin), and Saccharopolyspora hirsuta ATCC 20501 (sporaricin). This suggests that these genes of similar function from different genera were derived from a common ancestral gene.

Actinomycetales↗

PubMed2004

Isolation and characterisation of antibiotic producing microorganisms in composted Nigerian soil.

Compost samples obtained from different locations within the premises of the university of Lagos were analysed to determine the presence and types of antibiotic-producing bacteria, fungi and actinomycetes using nutrient agar, potato Dextrose agar and starch casein nitrate agar respectively as culture media. A variety of bacteria were isolated and these included Staphylococcus aureus, B. subtilis, B. pumilis, B. lactesporus, B. megaterium, B. pulvifaciens, B. licheniformis, Streptococus spp., Corynebacterium spp. and E. coli. The fungal isolates encountered were Aspergillus niger, A. flarus, T. viridae, P. chrysogenum, P. pinofylum and Absida spp., while the following actinomycetes were identified: Norcadia spp., Micromonospora spp., Streptomyces scabies, S. reticuli and S. hygroscopicus. When these organisms were screened for antibiosis, the following species were found to be antibiotic producers: B. licheniformis, B. subtilis, Penicillium chrysogenum, Streptomyces reticuli, S. hygroscopicus and Micromonospora spp. The fungus Penicillium chrysogenum had the highest rate of antibiotic production with an inhibitory zone width of 17mm while Trichoderma viridae produced toxins lytic to other fungal hyphae.

Actinomycetales↗

PubMed1999

Sch-27899 (Schering-Plough Corp).

Sch27899 (Ziracin) is an oligosaccharide antibiotic under development by Schering-Plough as a potential treatment for Gram-positive bacterial infection, including vancomycin- and methicillin-resistant bacteria. It is being evaluated in phase III clinical trials. Sch-27899 is a member of the naturally occurring class of everninomicins and was isolated from Micromonospora. Sch-27899 and the Micromonospora strain producing it were first disclosed in US04597968. The cyclodextrin complex, which overcomes the toxicity problems of Sch27899, is claimed in EP00538011.

Journal Article↗

PubMedDate not supplied

[Number and structure of actinomycetes complexes in the rhizosphere winter rye, oat and red clover].

The actinomycetes complexes in the rhizosphere of three agricultural plants by using the methods of luminescense microscopy and cup sowing were investigated. It was established, that concentration of prokaryotic biomass and biomass of actinomycetes mycelium in rhizosphere of plants is higher than in free from the radicals to soil. Rhizosphera of the oat (Avena sativa L.) and red clover (Trifolium pratense L.) is colonized by Streptomyces, Micromonospora and olygospore species. Dominante actinomycetes of winter rye (Secale cereale L.) are classified into the genera Micromonospora. It was shown that numbers and biomass of actinomycetes mycelium were fond to decreased, diversity of actinomycetes in contrast is increased in the series: "winter rye--oat--red clover". In connection with ecological safety the capability of increase with prokaryotes naturally disease suppressive soil and stability of plants to pathogen is discussed.

Actinobacteria↗

PubMed1991

[Comparative evaluation of various bacterial growth inhibitors as selective agents for isolation of soil Actinomyces].

Tobramycin and dioxidine sensitivity of 57 strains belonging to 14 actinomycetes genera was studied. The cultures of Streptomyces were much more sensitive to tobramycin than the cultures of rare genera. The majority of the Streptomyces cultures showed a high resistance to dioxidine (MIC greater than or equal to 50 micrograms/ml). At the same time the majority of the cultures of rare genera were inhibited by low concentrations of dioxidine (no more than 50 micrograms/ml). For isolation of actinomycetes from soil samples, tobramycin, dioxidine, ceftriaxone and novobiocin were used. Tobramycin added in a concentration of 10 micrograms/ml to the Gauze agar organic medium No. 2 promoted a 2-fold increase in detection of actinomycetes of the rare genera as compared to the control. It was especially favourable for detection of cultures belonging to Micromonospora, Amycolatopsis, Streptosporangium and Nocardiopsis. Dioxidine in concentrations of 10 and 50 micrograms/ml inhibited the growth of the cultures belonging to rare genera. Ceftriaxone in the same concentrations inhibited the growth of the cultures of both Streptomyces and the rare genera. Novobiocin favoured detection of the cultures belonging to Amicolatopsis and Micromonospora. Therefore, among the tested compounds tobramycin and novobiocin appeared to be the most useful selective agents for isolation of actinomycetes of rare genera.

Actinomyces↗