| ultrastructural studies of sporulation in streptomyces. | this is the first study of sporogenesis in streptomyces carried out on a relatively high number of species (seven) which allows us, using also previously published results, to establish a general picture of this process. in the sporogenesis of streptomyces two basic stages can be considered: the sporulation septum synthesis and the arthrospore maturation. our ultrastructural study of the sporulation septum formation suggests the existance within this genus of three basic types. type i is disting ... | 1976 | 821930 |
| [the effect of monensin on performance and selected biochemical and hematological parameters in the blood of calves]. | the aim of this study was to find out the influence of monensin, a ionophore antibiotic, on calf performance and selected physiological parameters. monensin is a product of streptomyces cinnamonensis. it has effects on all gram-negative microbes, such as escherichia coli, salmonellas, pseudomonads and vibria. it has a small effect on gram-positive microbes. at the beginning of the experiment eight young crossbred bulls (c x n) at the age of three weeks were weighted and divided into two groups, ... | 1992 | 1292174 |
| characterisation of acti-homologous dna encoding polyketide synthase genes from the monensin producer streptomyces cinnamonensis. | cloned dna encoding polyketide synthase (pks) genes from one streptomyces species was previously shown to serve as a useful hybridisation probe for the isolation of other pks gene clusters from the same or different species. in this work, the acti and actiii genes, encoding components of the actinorhodin pks of streptomyces coelicolor, were used to identify and clone a region of homologous dna from the monensin-producing organism s. cinnamonensis. a 4799 bp fragment containing the s. cinnamonens ... | 1992 | 1508151 |
| transposition of tn5096 from a temperature-sensitive transducible plasmid in streptomyces spp. | transposon tn5096 was inserted into a derivative of the temperature-sensitive plasmid pmt660 containing the bacteriophage fp43 pac site. the resulting plasmid, prhb126, was transduced by fp43 into several streptomyces species. tn5096 transposed from prhb126 into different sites in the genomes of streptomyces ambofaciens, streptomyces cinnamonensis, streptomyces coelicolor a3(2), streptomyces fradiae, streptomyces griseofuscus, and streptomyces thermotolerans. | 1991 | 1653214 |
| resistance of streptomyces cinnamonensis to butyrate and isobutyrate: production and properties of a new anti-isobutyrate (aib) factor. | butyrate and isobutyrate (after isomerization to n-butyrate) are specific precursors for the biosynthesis of monensin a in streptomyces cinnamonensis. high concentrations of both butyrate and isobutyrate (greater than 20 and 10 mm, respectively) were toxic to s. cinnamonensis plated on solid medium. spontaneous mutants resistant to these substances were isolated. these new strains produced monensins at even higher concentrations of butyrate or isobutyrate, with an increased yield of monensin a. ... | 1991 | 1748869 |
| mutant strains of streptomyces cinnamonensis protoplasts. cultural and physiological conditions. | mycelium of streptomyces cinnamonensis mutant strains cultivated in a synthetic medium with glycine produced protoplasts after lysis of cell walls with lysozyme. the protoplast yield was up to 95%. the protoplasts could revert and mycelial forms were thus regenerated. in a sucrose-containing medium the protoplasts stored at 4 degrees c were stable for 2 d. | 1991 | 1841848 |
| preparation of protoplasts and regeneration of intact cells of streptomyces cinnamonensis. | protoplasts were prepared and intact cells were regenerated in streptomyces cinnamonensis--a monensin producer--to make genetic manipulations with this strain possible. 70-80% of protoplasts were formed and up to 90% of them could regenerate into intact cells. | 1990 | 2269446 |
| vitamins as effectors of monensin production by streptomyces cinnamonensis. | vitamins added to submerged streptomyces cinnamonensis cultures stimulated the production of monensins. vitamins b2, b3, b5 and b12 enhanced the production by about 50%, vitamins b1 and b6 by 100%. the addition of biotin in optimal concentration resulted in more than 3-fold increase in total production. | 1990 | 2269447 |
| preparative high-performance liquid chromatography of minor products of streptomyces cinnamonensis. | analytical and preparative high-performance liquid chromatography of 3 phenazines and furonaphthoquinone derivative on reversed-phase column are described. the mobile phase was methanol and water. the injected amount of the mixture was about 30 mg for a preparative chromatographic run requiring 80 min. substances were detected directly in the column effluent by uv detection. | 1990 | 2379888 |
| selection of a specifically blocked mutant of streptomyces cinnamonensis: isolation and synthesis of 26-deoxymonensin a. | streptomyces cinnamonensis produces the polyether ionophore antibiotic monensin a. following a single round of mutagenesis by uv light, a derivative of this strain has been isolated, which secretes a new metabolite identified as 26-deoxymonensin a (3). the structural elucidation of the new metabolite followed from a spectroscopic analysis, and its identity was proven conclusively following a comparison to 26-deoxymonensin a (3) obtained synthetically from monensin a. the preparation of labelled ... | 1989 | 2753815 |
| purification and catalytic properties of l-valine dehydrogenase from streptomyces cinnamonensis. | nad+-dependent l-valine dehydrogenase was purified 180-fold from streptomyces cinnamonensis, and to homogeneity, as judged by gel electrophoresis. the enzyme has an mr of 88,000, and appears to be composed of subunits of mr 41,200. the enzyme catalyses the oxidative deamination of l-valine, l-leucine, l-2-aminobutyric acid, l-norvaline and l-isoleucine, as well as the reductive amination of their 2-oxo analogues. the enzyme requires nad+ as the only cofactor, which cannot be replaced by nadp+. t ... | 1989 | 2803248 |
| propionate and the production of monensins in streptomyces cinnamonensis. | variants resistant to propionate were prepared from a mutant strain of streptomyces cinnamonensis producing predominantly monensin a. using selected resistants the production of monensins (in media with higher concentrations of propionate) was examined. stimulation of monensin synthesis by propionate was observed with 70% of the resistants studied. propionate did not influence the ratio between monensin a and b production. | 1988 | 3240905 |
| 3-o-demethylmonensins a and b produced by streptomyces cinnamonensis. | | 1987 | 3583923 |
| biosynthesis of monensins a and b: the role of isoleucine. | isoleucine added to the cultivation medium of streptomyces cinnamonensis c-100-5 induced a relative increase of the production of monensin b at the expense of monensin a. u-14c-isoleucine was found not to be a specific monensin b precursor. the incorporation of 1-13c-2-methylbutyrate into monensins a and b showed the label to be evenly incorporated in both products at carbon atoms originating from c(1) of propionate. in regulatory mutants insensitive to 2-amino-3-chlorobutyrate isoleucine influe ... | 1986 | 3957157 |
| biosynthesis of monensin. | the biosynthesis of monensin by streptomyces cinnamonensis was studied by using (14)c-labeled glucose, acetate, propionate, butyrate, and methionine. the results indicated that the antibiotic is synthesized from five acetate, seven propionate, and one butyrate molecules. the o-methyl group of monensin is derived from methionine, whereas the terminal hydroxymethyl group is incorporated from acetate. | 1973 | 4791301 |
| observation of the nuclear behavior in streptomyces cinnamonensis. | | 1966 | 5934866 |
| improving the production of monensin by streptomyces cinnamonensis. | the production of monensin by streptomyces cinnamonensis was increased by genetic improvement of the strain and by modification of cultivation conditions. the selection of a suitable strain and optimization of the fermentation process (temperature, aeration, addition of esters of oleic acid) resulted in a 30 fold increase of the monensin production. | 1984 | 6370806 |
| effects of monensin on metabolism of isolated rat islets of langerhans. | monensin, a univalent ionophore, is a carboxylic acid produced by streptomyces cinnamonensis. it will complex various alkali-metal ions, but most readily binds na+. because of interest in the possible role of na+ in the regulation of insulin secretion, we examined its effects on several aspects of the metabolism of isolated rat islets of langerhans. the ionophore inhibited glucose-stimulated insulin release in a concentration-dependent manner, completely inhibiting secretion evoked by 20 mm-gluc ... | 1984 | 6388569 |
| [determination of several antibiotics using voltamperometry at the interface of nitrobenzene and water]. | a new electroanalytical method of voltamperometry at the interface of two immiscible electrolyte solutions (ities) is based on electrochemical polarization of a liquid/liquid interface. the resulting current voltage characteristics completely resemble those obtained with metallic electrodes. the charge transfer processes are either the direct ion transfer across the ities or the transfer facilitated by macrocyclic ionophores. determination of tetracycline antibiotics is based on the direct trans ... | 1983 | 6689115 |
| fatty acids of streptomyces cinnamonensis, producer of monensin. | using the gas chromatography-mass spectrometry (gc-ms) method we found in streptomyces cinnamonensis saturated fatty acids of iso- and anteiso- types, cyclopropyl acids, and unsaturated fatty acids where the double bond position was determined by ms of their pyrrolidine derivatives. | 1984 | 6745817 |
| production of phenazines by streptomyces cinnamonensis. | | 1983 | 6832658 |
| novel polyether antibiotics x-14667a and x-14667b from streptomyces cinnamonensis subsp. urethanofaciens. discovery, fermentation, biological as well as ionophore properties and taxonomy of the producing culture. | | 1981 | 7309619 |
| isolation of novel antibiotics x-14667a and x-14667b from streptomyces cinnamonensis subsp. urethanofaciens and their characterization as 2-phenethylurethanes of monensins b and a. | antibiotics x-14667a (1) and x-14667b (2) are novel monovalent polyether antibiotics of the spiroketal type isolated from fermented cultures of streptomyces cinnamonensis subsp. urethanofaciens together with monensin (3), its lower homolog, factor b (4) and 1,3-diphenethylurea (6). by a combination of microanalysis, mass spectrometry and 13c nmr, antibiotics x-14667a and b have been shown to be natural 2-phenethylurethanes of monensin b and a respectively. both structures have been confirmed by ... | 1981 | 7309620 |
| production of 26-deoxymonensins a and b by streptomyces cinnamonensis in the presence of metyrapone. | metyrapone, a potent cytochrome p-450 inhibitor, added at 9 mm to a submerged culture of streptomyces cinnamonensis caused partial inhibition of total monensin biosynthesis and coproduction of new metabolites, 26-deoxymonensins a and b. the latter was isolated as its 25-o-methyl derivative. metyrapone was simultaneously reduced to metyrapol. all of these compounds were identified by nuclear magnetic resonance spectroscopy and mass spectrometry. | 1994 | 8017935 |
| cloning, sequencing, and expression of the gene encoding methylmalonyl-coenzyme a mutase from streptomyces cinnamonensis. | in streptomycetes, the conversion of succinyl-coenzyme a (coa) into methylmalonyl-coa, catalyzed by methylmalonyl-coa mutase, most likely represents an important source of building blocks for polyketide antibiotic biosynthesis. in this work, the structural gene for methylmalonyl-coa mutase from streptomyces cinnamonensis was cloned by using a heterologous gene probe encoding the mutase from propionibacterium shermanii. a 5,732-bp fragment was sequenced, within which four open reading frames were ... | 1993 | 8099072 |
| activity of the aib factor observed in prokaryotic and eukaryotic microorganisms. | streptomyces cinnamonensis produces a new substance named aib (for anti-isobutyrate) factor which, on a solid medium, efficiently counteracts toxic concentrations not only of isobutyrate but also of other salts of short-chain monocarboxylic acids. in the present study we demonstrate that the aib factor activity is widely spread because this effect was positively detected in 25 of 31 randomly chosen microorganisms (streptomycetes, ascomycetes, zygomycetes and basidiomycetes). the aib factor produ ... | 1993 | 8375780 |
| the biosynthesis of monensin-a: thymine, beta-aminoisobutyrate and methacrylate metabolism in streptomyces cinnamonensis. | feeding experiments with isotopically labelled samples of [13c,2h3-methyl]-thymine, (r,s)-[i-13c]- and (r,s-[13c-methyl]-beta-aminoisobutyrates into monensin-a demonstrate that these metabolites can all contribute to the methylmalonyl-coa pool in streptomyces cinnamonensis, and implicate dna catabolism as a contributory metabolic source of propionate carbon atoms for secondary metabolic biosynthesis. further, these labelled compounds were unexpectedly incorporated into the butyrate unit of monen ... | 1995 | 8557569 |
| metabolic pathway for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) formation in nocardia corallina: inactivation of mutb by chromosomal integration of a kanamycin resistance gene. | the gene encoding the large subunit of the methylmalonyl-coenzyme a (coa) mutase in nocardia corallina (mutbnc) was cloned. a 4.3-kbp bamhi fragment containing almost the entire mutbnc was identified by southern hybridization experiments employing a digoxigenin-labeled probe deduced from mutb of streptomyces cinnamonensis, mutbnc was interrupted by insertion of a kanamycin resistance gene block (mutb::kan or mutb::neo) and introduced into n. corallina to obtain mutb-negative strains by homologou ... | 1996 | 8593043 |
| [induction of antibiotic production in inactive cultures of actinomycetes. monensin production by a mutant strain 2608 eb-1]. | an actinomycete strain designated as 2608 was isolated from a soil sample. when cultivated on various solid and liquid media, the strain was inactive. the strain exposure to ethidium bromide resulted in formation of a mutant producing an antibiotic active against some gram-positive bacteria. the property of the antibiotic production proved to be stable. the antibiotic was identified by ir, nmr and mass spectroscopy as monensin. strain 2608 producing monensin differs from the described monensin-p ... | 1995 | 8660117 |
| cloning, sequencing, overexpression in escherichia coli, and inactivation of the valine dehydrogenase gene in the polyether antibiotic producer streptomyces cinnamonensis. | the catabolism of branched chain amino acids, especially valine, appears to play an important role in furnishing building blocks for macrolide antibiotic biosynthesis. to determine for the first time the importance of valine dehydrogenase (vdh) in polyether antibiotic biosynthesis, the vdh gene from streptomyces cinnamonensis has been cloned and sequenced. the enzyme (m(r)37,718 da) has been produced in large amounts in an active form in the e. coli cytoplasm using a t7 rna-polymerase expression ... | 1996 | 8921870 |
| 2-demethylmonensins a and b. novel minor congeners of monensins from streptomyces cinnamonensis. | | 1996 | 8931729 |
| analysis of the quaternary structure, substrate specificity, and catalytic mechanism of valine dehydrogenase. | the solution of the three-dimensional structure of bacillus sphaericus leucine dehydrogenase has enabled us to undertake a homology-based modeling exercise on the sequence differences between the families of leucine (leudh) and valine (valdh) dehydrogenases. this analysis indicates that the secondary structure elements in the core of the two domains of a single subunit of these enzymes are conserved, as are residues directly implicated in the recognition of the nucleotide cofactor and in catalys ... | 1997 | 9312120 |
| cloning, sequencing, expression, and insertional inactivation of the gene for the large subunit of the coenzyme b12-dependent isobutyryl-coa mutase from streptomyces cinnamonensis. | purification of the coenzyme b12-dependent isobutyryl-coa mutase (icm) from streptomyces cinnamonensis gave a protein of approximately 65 kda by sds-polyacrylamide gel electrophoresis, whose gene icma was cloned using sequences derived from tryptic peptide fragments. the gene encodes a protein of 566 residues (62, 487 da), with 43-44% sequence identity to the large subunit of methylmalonyl-coa mutase (mcm) from s. cinnamonensis and propionibacterium shermanii. targeted disruption of the icma gen ... | 1998 | 9497386 |
| kytococcus sedentarius (formerly micrococcus sedentarius) and dermacoccus nishinomiyaensis (formerly micrococcus nishinomiyaensis) produce monensins, typical streptomyces cinnamonensis metabolites. | the environmental isolate kytococcus sedentarius tr-2 was found to be a new producer of the oligoketide antibiotics monensin a and b. electron microscopic studies demonstrated that the tr-2 strain had coccoid cells and dna analysis revealed no close relationship to streptomyces cinnamonensis, a typical monensin producer. production of monensins was also proven with six culture collection k. sedentarius strains and three dermacoccus nishinomiyaensis strains. the secondary metabolism of micrococci ... | 1998 | 9933918 |
| insertional inactivation of methylmalonyl coenzyme a (coa) mutase and isobutyryl-coa mutase genes in streptomyces cinnamonensis: influence on polyketide antibiotic biosynthesis. | the coenzyme b(12)-dependent isobutyryl coenzyme a (coa) mutase (icm) and methylmalonyl-coa mutase (mcm) catalyze the isomerization of n-butyryl-coa to isobutyryl-coa and of methylmalonyl-coa to succinyl-coa, respectively. the influence that both mutases have on the conversion of n- and isobutyryl-coa to methylmalonyl-coa and the use of the latter in polyketide biosynthesis have been investigated with the polyether antibiotic (monensin) producer streptomyces cinnamonensis. mutants prepared by in ... | 1999 | 10482499 |
| cloning and sequencing of the coenzyme b(12)-binding domain of isobutyryl-coa mutase from streptomyces cinnamonensis, reconstitution of mutase activity, and characterization of the recombinant enzyme produced in escherichia coli. | isobutyryl-coa mutase (icm) catalyzes the reversible, coenzyme b(12)-dependent rearrangement of isobutyryl-coa to n-butyryl-coa, which is similar to, but distinct from, that catalyzed by methylmalonyl-coa mutase. icm has been detected so far in a variety of aerobic and anaerobic bacteria, where it appears to play a key role in valine and fatty acid catabolism. icm from streptomyces cinnamonensis is composed of a large subunit (icma) of 62.5 kda and a small subunit (icmb) of 14.3 kda. icmb encode ... | 1999 | 10531377 |
| role of crotonyl coenzyme a reductase in determining the ratio of polyketides monensin a and monensin b produced by streptomyces cinnamonensis. | the ccr gene, encoding crotonyl coenzyme a (coa) reductase (ccr), was cloned from streptomyces cinnamonensis c730.1 and shown to encode a protein with 90% amino acid sequence identity to the ccrs of streptomyces collinus and streptomyces coelicolor. a ccr-disrupted mutant, s. cinnamonensis l1, was constructed by inserting the hyg resistance gene into a unique bglii site within the ccr coding region. by use of the erme* promoter, the s. collinus ccr gene was expressed from plasmids in s. cinnamon ... | 1999 | 10542184 |
| mutations in two distinct regions of acetolactate synthase regulatory subunit from streptomyces cinnamonensis result in the lack of sensitivity to end-product inhibition. | acetolactate synthase small subunit encoding ilvn genes from the parental streptomyces cinnamonensis strain and mutants resistant either to valine analogues or to 2-ketobutyrate were cloned and sequenced. the wild-type ilvn from s. cinnamonensis is composed of 175 amino acid residues and shows a high degree of similarity with the small subunits of other valine-sensitive bacterial acetolactate synthases. changes in the sequence of ilvn conferring the insensitivity to valine in mutant strains were ... | 1999 | 10581183 |
| a novel transmembrane serine/threonine protein kinase gene from a rifamycin sv-producing amycolatopsis mediterranei u32. | genomic dna sequencing in the vicinity of methylmalonyl-coa mutase gene (mutab) from a rifamycin sv-producing amycolatopsis mediterranei u32 allowed us to clone, sequence, and identify a gene encoding a novel serine/threonine protein kinase (amk). the sequence contains a complete orf of 1821 base pairs encoding a predicted protein of 606 amino acids in length. the n-terminal domain of the protein shows significant homology to the catalytic domain of other protein kinases from both prokaryotic an ... | 2000 | 10848993 |
| precursor supply for polyketide biosynthesis: the role of crotonyl-coa reductase. | crotonyl-coa reductase (ccr), which catalyzes the reduction of crotonyl-coa to butyryl-coa, is common to most streptomycetes and appears to be inducible by either lysine or its catabolites in streptomyces cinnamonensis grown in chemically defined medium. a major role of ccr in providing butyryl-coa from acetate for monensin a biosynthesis has been demonstrated by the observation of a change in the monensin a/monensin b ratio in the parent c730.1 strain (50/50) and a ccr (encoding ccr) disruptant ... | 2001 | 11162231 |
| meaa, a putative coenzyme b12-dependent mutase, provides methylmalonyl coenzyme a for monensin biosynthesis in streptomyces cinnamonensis. | the ratio of the major monensin analogs produced by streptomyces cinnamonensis is dependent upon the relative levels of the biosynthetic precursors methylmalonyl-coenzyme a (coa) (monensin a and monensin b) and ethylmalonyl-coa (monensin a). the meaa gene of this organism was cloned and sequenced and was shown to encode a putative 74-kda protein with significant amino acid sequence identity to methylmalonyl-coa mutase (mcm) (40%) and isobutyryl-coa mutase (icm) large subunit (36%) and small subu ... | 2001 | 11222607 |
| [the effects of vitreoscilla hemoglobin expression on growth and antibiotic production in streptomyces cinnamonensis]. | streptomyces cinnamonensis a-10 is a monensin \ producing strain. phz1252 is an e. coli-streptomyces shuttle vector for expressing vhb, in which vhb structural gene is controlled by thiostrepton-inducible promoter ptipa. phz1252 was unstable in s. cinnamonensis, occurring deletion recombination. the deletion dna fragment of phz1252 included not only part of e. coli plasmid but also vhb gene. however, plasmid phz1252 isolated from s. avermitilis transformants, which lost part of e. coli plasmid b ... | 2001 | 11336066 |
| engineering of ralstonia eutropha for production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from fructose and solid-state properties of the copolymer. | recombinant ralstonia eutropha capable of producing poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer [p(3hb-co-3hhx)] from fructose was engineered by introduction of genes for crotonyl-coa reductase (ccr) from streptomyces cinnamonensis (ccrsc) and for pha synthase and (r)-specific enoyl-coa hydratase from aeromonas caviae (phac-jac). in this recombinant strain, c6-acyl-coa intermediates were provided via beta-ketothiolase-mediated elongation of butyryl-coa, which was generated from croto ... | 2002 | 12005535 |
| increasing the efficiency of heterologous promoters in actinomycetes. | an escherichia coli-actinomycete shuttle vector, pcjw93, was constructed which places cloned genes under the control of the thiostrepton-inducible tip promoter from streptomyces lividans. we also constructed expression vectors bearing the actii-orf4/pacti activator-promoter system of the actinorhodin biosynthetic pathway of streptomyces coelicolor. with both types of vector, levels of expression varied widely in different actinomycete strains, indicating different levels of the host factors need ... | 2002 | 12125822 |
| analysis of the biosynthetic gene cluster for the polyether antibiotic monensin in streptomyces cinnamonensis and evidence for the role of monb and monc genes in oxidative cyclization. | the analysis of a candidate biosynthetic gene cluster (97 kbp) for the polyether ionophore monensin from streptomyces cinnamonensis has revealed a modular polyketide synthase composed of eight separate multienzyme subunits housing a total of 12 extension modules, and flanked by numerous other genes for which a plausible function in monensin biosynthesis can be ascribed. deletion of essentially all these clustered genes specifically abolished monensin production, while overexpression in s. cinnam ... | 2003 | 12940979 |
| on streptomyces cinnamonensis n. sp., the source of an antitubercular antibiotic of low toxicity. | | 1953 | 13084301 |
| chemical studies on antibiotic substances. iii. on an anti-mycobacterial antibiotic produced by streptomyces cinnamonensis n. sp. | | 1953 | 13096199 |
| crotonyl-coenzyme a reductase provides methylmalonyl-coa precursors for monensin biosynthesis by streptomyces cinnamonensis in an oil-based extended fermentation. | it is demonstrated that crotonyl-coa reductase (ccr) plays a significant role in providing methylmalonyl-coa for monensin biosynthesis in oil-based 10-day fermentations of streptomyces cinnamonensis. under these conditions s. cinnamonensis l1, a derivative of a high-titre producing industrial strain c730.1 in which ccr has been insertionally inactivated, produces only 15 % of the monensin yield. labelling of the coenzyme a pools using [3h]-beta-alanine and analysis of intracellular acyl-coas in ... | 2004 | 15470123 |
| multiple pathways for acetate assimilation in streptomyces cinnamonensis. | in most bacteria acetate assimilation is accomplished via the glyoxylate pathway. isocitrate lyase (icl) and malate synthase (ms) are two key enzymes of this pathway, which results in the net generation of one molecule of succinyl-coa from two acetyl-coa molecules. genetic and biochemical data have shown that genes encoding these key enzymes are present in streptomycetes, yet there has been no clear demonstration of the importance of these genes to acetate assimilation. in fact, for streptomyces ... | 2006 | 16187095 |
| identification and disruptional analysis of the streptomyces cinnamonensis msda gene, encoding methylmalonic acid semialdehyde dehydrogenase. | the msda gene encodes methylmalonic acid semialdehyde dehydrogenase (msdh) and is known to be involved in valine catabolism in streptomyces coelicolor. using degenerative primers, a homolog of msda gene was cloned and sequenced from the monensin producer, streptomyces cinnamonensis. rt-pcr results showed msda was expressed in a vegetative culture, bump-seed culture and the early stages of oil-based monensin fermentation. however, isotopic labeling of monensin a by [2, 4-(13)c(2)]butyrate reveale ... | 2006 | 16292556 |
| evidence that a novel thioesterase is responsible for polyketide chain release during biosynthesis of the polyether ionophore monensin. | polyether ionophores, such as monensin a, are known to be biosynthesised, like many other antibiotic polyketides, on giant modular polyketide synthases (pkss), but the intermediates and enzymes involved in the subsequent steps of oxidative cyclisation remain undefined. in particular there has been no agreement on the mechanism and timing of the final polyketide chain release. we now report evidence that moncii from the monensin biosynthetic gene cluster in streptomyces cinnamonensis, which was p ... | 2006 | 16897798 |
| a gene cluster for prenylated naphthoquinone and prenylated phenazine biosynthesis in streptomyces cinnamonensis dsm 1042. | streptomyces cinnamonensis dsm 1042 produces two classes of secondary metabolites of mixed isoprenoid/nonisoprenoid origin: the polyketide-isoprenoid compound furanonaphthoquinone i (fnq i) and several prenylated phenazines, predominantly endophenazine a. we now report the cloning and sequence analysis of a 55 kb gene cluster required for the biosynthesis of these compounds. several inactivation experiments confirmed the involvement of this gene cluster in the biosynthesis of fnq i and endophena ... | 2006 | 17103476 |
| biosynthesis of the isoprenoid moieties of furanonaphthoquinone i and endophenazine a in streptomyces cinnamonensis dsm 1042. | streptomyces cinnamonensis dsm 1042 produces the polyketide-isoprenoid compound furanonaphthoquinone i (fnq i) and isoprenylated phenazines, predominantly endophenazine a. however, the recently identified biosynthetic gene cluster for these compounds only contains a single gene for a mevalonate pathway enzyme, that is, a putative mevalonate kinase gene. this is in strong contrast to all streptomyces strains examined so far, where all six genes encoding the mevalonate pathway enzymes are clustere ... | 2007 | 17474781 |
| a soluble, magnesium-independent prenyltransferase catalyzes reverse and regular c-prenylations and o-prenylations of aromatic substrates. | fnq26 from streptomyces cinnamonensis dsm 1042 is a new member of the recently identified cloq/orf2 class of prenyltransferases. the enzyme was overexpressed in e. coli and purified to apparent homogeneity, resulting in a soluble, monomeric protein of 33.2 kda. the catalytic activity of fnq26 is independent of the presence of mg(2+) or other divalent metal ions. with flaviolin (2,5,7-trihydroxy-1,4-naphthoquinone) as substrate, fnq26 catalyzes the formation of a carbon-carbon-bond between c-3 (r ... | 2007 | 17543953 |
| european field evaluation of monensin, a new anticoccidial agent. | the efficacy of monensin, a fermentation product of streptomyces cinnamonensis was evaluated and compared with four commonly used anticoccidial agents in the control of naturally occurring coccidial infection of broiler chickens. results are reported from 25 floor pen trials, involving 90,678 birds allotted to 289 replicates, at 11 locations in england, france, holland and spain. untreated control groups of birds were included where possible to measure the degree of exposure to infection. parame ... | 1974 | 18777254 |
| lines of evidence for horizontal gene transfer of a phenazine producing operon into multiple bacterial species. | phenazines are secondary metabolites with broad-spectrum antibiotic activity against bacteria, fungi, and eukaryotes. in pseudomonad species, a conserved seven-gene phenazine operon (phzabcdefg) is required for the conversion of chorismic acid to the broad-spectrum antibiotic phenazine-1-carboxylate. previous analyses of genes involved in phenazine production from nonpseudomonad species uncovered a high degree of sequence similarity to pseudomonad homologues. the analyses undertaken in this stud ... | 2009 | 19189039 |
| deregulation of acetohydroxy-acid synthase: loss of allosteric inhibition conferred by mutations in the catalytic subunit. | acetohydroxy-acid synthases (ahas) of two mutant strains streptomyces cinnamonensis acb-nlr-2 and bvr-18 were chosen for this study for their apparent activation by valine, which regularly acts as an allosteric inhibitor. sequencing the ilvb genes coding for the ahas catalytic subunit revealed two distant changes in the mutants, deltaq217 and e139a, respectively. homology modeling was used to propose the structural changes caused by those mutations. in the mutant strain acb-nlr-2 (resistant to 2 ... | 2009 | 19381469 |
| high titer production of tetracenomycins by heterologous expression of the pathway in a streptomyces cinnamonensis industrial monensin producer strain. | streptomyces cinnamonensis c730.1 and c730.7, are industrially mutagenized strains that produce moderate and high levels of the polyketide polyether antibiotic monensin a, respectively, in an oil-based fermentation medium. the possibility that these strains could be used for high titer production of a heterologous polyketide product was investigated by expression of the entire tetracenomycin (tcm) biosynthetic pathway using an integrative plasmid, pset154. expression in c730.1 led to stable prod ... | 2009 | 19595787 |
| subunit-subunit interactions are weakened in mutant forms of acetohydroxy acid synthase insensitive to valine inhibition. | in acetohydroxy acid synthase from streptomyces cinnamonensis mutants affected in valine regulation, the impact of mutations on interactions between the catalytic and the regulatory subunits was examined using yeast two-hybrid system. mutations in the catalytic and the regulatory subunits were projected into homology models of the respective proteins. two changes in the catalytic subunit, e139a (alpha domain) and deltaq217 (beta domain), both located on the surface of the catalytic subunit dimer ... | 2010 | 20107768 |
| robust reporter system based on chalcone synthase rppa gene from saccharopolyspora erythraea. | industrial overproducing strains present unique hosts for expression of heterologous gene clusters encoding secondary metabolite biosynthesis. for this purpose, efficient gene expression tools and methods are needed. a robust and versatile reporter system based on the rppa gene from saccharopolyspora erythraea is presented as the method of choice when studying gene expression in actinomycete hosts. the method is easily scalable to accommodate high-throughput procedure, and collected samples can ... | 2010 | 20709115 |
| identification of streptomyces sp. kh29, which produces an antibiotic substance processing an inhibitory activity against multidrug-resistant acinetobacter baumannii. | the actinomycete strain kh29 is antagonistic to the multidrug-resistant acinetobacter baumannii. based on the diaminopimelic acid (dap) type, and the morphological and physiological characteristics observed through the use of scanning electron microscopy (sem), kh29 was confirmed as belonging to the genus streptomyces. by way of its noted 16s rdna nucleotide sequences, kh29 was found to have a relationship with streptomyces cinnamonensis. the production of an antibiotic from this strain was foun ... | 2010 | 21193822 |
| the biosynthetic genes for prenylated phenazines are located at two different chromosomal loci of streptomyces cinnamonensis dsm 1042. | streptomyces cinnamonensis dsm 1042 produces two types of isoprenoid secondary metabolites: the prenylated naphthalene derivative furanonaphthoquinone i (fnq i), and isoprenylated phenazines which are termed endophenazines. previously, a 55 kb gene cluster was identified which contained genes for both fnq i and endophenazine biosynthesis. however, several genes required for the biosynthesis of these metabolites were not present in this cluster. we now re-screened the cosmid library for genes of ... | 2010 | 21342470 |
| oxidation and amidation of salicylate by streptomyces species. | seven streptomycete strains were tested for biotransformation of salicylate. the products were identified by nuclear magnetic resonance spectroscopy and three types of conversion were found. streptomyces cinnamonensis and streptomyces spectabilis formed gentisate and salicylamide concurrently. streptomyces rimosus transformed salicylate to salicylamide. streptomyces lividans, streptomyces coelicolor, streptomyces griseus and streptomyces avermitilis produced only gentisate. time course studies o ... | 1996 | 22050000 |
| site-specific recombination strategies for engineering actinomycete genomes. | the feasibility of using technologies based on site-specific recombination in actinomycetes was shown several years ago. despite their huge potential, these technologies mostly have been used for simple marker removal from a chromosome. in this paper, we present different site-specific recombination strategies for genome engineering in several actinomycetes belonging to the genera streptomyces, micromonospora, and saccharothrix. two different systems based on cre/loxp and dre/rox have been utili ... | 2012 | 22247163 |
| dasr positively controls monensin production at two-level regulation in streptomyces cinnamonensis. | the polyether ionophore antibiotic monensin is produced by streptomyces cinnamonensis and is used as a coccidiostat for chickens and growth-promoting agent for cattle. monensin biosynthetic gene cluster has been cloned and partially characterized. the gntr-family transcription factor dasr regulates antibiotic production and morphological development in streptomyces coelicolor and saccharopolyspora erythraea. in this study, we identified and characterized the two-level regulatory cascade of dasr ... | 2016 | 27718094 |
| intermediates in monensin biosynthesis: a late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding. | polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. the resulting structures containing fused cyclic ethers and a lipophilic backbone can form strong ionophoric complexes with certain metal cations. in this work, we demonstrate for monensin biosynthesis that, as well as ether formation, a late-stage hydroxylation step is crucial for the correct formation of the sodium monensin complex. we have investig ... | 2014 | 24605157 |
| streptomyces manipurensis sp. nov., a novel actinomycete isolated from a limestone deposit site in manipur, india. | a novel actinobacterium, designated mbrl 201(t), was isolated from a sample collected from a limestone quarry at hundung, manipur, india. the strain was characterized using polyphasic taxonomy. comparison of the 16s rrna gene sequence of strain mbrl 201(t) and other streptomyces species showed sequence similarities ranging from 93.0 to 99.6 % and strain mbrl 201(t) showed closest similarities to streptomyces virginiae nbrc 12827(t) (99.6 %) and streptomyces cinnamonensis nbrc 15873(t) (99.6 %). ... | 2012 | 22421918 |