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unprecedented anthranilate priming involving two enzymes of the acyl adenylating superfamily in aurachin biosynthesis.biosynthesis of many polyketide-derived secondary metabolites is initiated by incorporating starter units other than acetate. thus, understanding their priming mechanism is of importance for metabolic engineering. insight into the loading process of anthranilate into the biosynthetic pathway for the quinoline alkaloids aurachins has been provided by the sequencing of a partial biosynthetic gene cluster in the myxobacterium stigmatella aurantiaca. the cluster encodes a predicted aryl:coa ligase a ...201121770425
evolution of antifreeze protein genes in the diatom genus fragilariopsis: evidence for horizontal gene transfer, gene duplication and episodic diversifying selection.hypotheses about horizontal transfer of antifreeze protein genes to ice-living diatoms were addressed using two different statistical methods available in the program prunier. the role of diversifying selection in driving the differentiation of a set of antifreeze protein genes in the diatom genus fragilariopsis was also investigated. four horizontal gene transfer events were identified. two of these took place between two major eukaryote lineages, that is from the diatom chaetoceros neogracile ...201122253534
fatty acid-related phylogeny of myxobacteria as an approach to discover polyunsaturated omega-3/6 fatty acids.in an analysis of 47 aerobic myxobacterial strains, representing 19 genera in suborders cystobacterineae, nannocystineae, sorangiineae, and a novel isolate, "aetherobacter" sbsr008, an enormously diverse array of fatty acids (fas) was found. the distribution of straight-chain fatty acids (scfas) and branched-chain fatty acids (bcfas) supports the reported clustering of strains in the phylogenetic tree based on 16s rrna genes. this finding additionally allows the prediction and assignment of the ...201121317327
investigation of cytochromes p450 in myxobacteria: excavation of cytochromes p450 from the genome of sorangium cellulosum so ce56.the exploitation of cytochromes p450 for novel biotechnological application and for the investigation of their physiological function is of great scientific interest in this post genomic era, where an extraordinary biodiversity of p450 genes has been derived from all forms of life. the study of p450s in the myxobacterium sorangium cellulosum strain so ce56, the producer of novel secondary metabolites of pharmaceutical interest is the research topic, in which we were engaged since the beginning o ...201121521637
auaa, a membrane-bound farnesyltransferase from stigmatella aurantiaca, catalyzes the prenylation of 2-methyl-4-hydroxyquinoline in the biosynthesis of aurachins.aurachins are quinoline alkaloids isolated from the myxobacterium stigmatella aurantiaca. they are substituted with an isoprenoid side chain and act as potent inhibitors in the electron transport chain. a biosynthetic gene cluster that contains at least five genes (auaa-auae) has been identified for aurachin biosynthesis. in this study, auaa, the gene encoding a putative prenyltransferase of 326 amino acids, was cloned and overexpressed in escherichia coli. biochemical investigations showed that ...201121671333
Completing the puzzle of aurachin biosynthesis in Stigmatella aurantiaca Sg a15.The aurachins are a family of secondary metabolites, with the main members aurachin A, B, C, and D, produced by the myxobacterium Stigmatella aurantiaca Sg a15. These isoprenoid quinoline alkaloids are classified as A-type or C-type aurachins according to the position of the farnesyl residue either at C4 or C3 of the quinoline core, respectively. Previous feeding studies revealed that the C-type aurachins are converted to A-type aurachins by late stage tailoring reactions. While the core gene cl ...201121979787
insights into multienzyme docking in hybrid pks-nrps megasynthetases revealed by heterologous expression and genetic engineering. 201020391455
comparative genomic analysis of fruiting body formation in myxococcales.genetic programs underlying multicellular morphogenesis and cellular differentiation are most often associated with eukaryotic organisms, but examples also exist in bacteria such as the formation of multicellular, spore-filled fruiting bodies in the order myxococcales. most members of the myxococcales undergo a multicellular developmental program culminating in the formation of spore-filled fruiting bodies in response to starvation. to gain insight into the evolutionary history of fruiting body ...201021037205
phylogenetic analysis of the triterpene cyclase protein family in prokaryotes and eukaryotes suggests bidirectional lateral gene transfer.functional constraints to modifications in triterpene cyclase amino acid sequences make them good candidates for evolutionary studies on the phylogenetic relatedness of these enzymes in prokaryotes as well as in eukaryotes. in this study, we used a set of identified triterpene cyclases, a group of mainly bacterial squalene cyclases and a group of predominantly eukaryotic oxidosqualene cyclases, as seed sequences to identify 5288 putative triterpene cyclase homologues in publicly available databa ...200919207562
biosynthesis of 2-hydroxy and iso-even fatty acids is connected to sphingolipid formation in myxobacteria.2-hydroxy fatty acids can be found in several different organisms, including bacteria. in this study, we have studied the biosynthesis of 2-hydroxy fatty acids in the myxobacteria myxococcus xanthus and stigmatella aurantiaca, resulting in the identification of a family of stereospecific fatty acid alpha-hydroxylases. although the stereospecificities of the hydroxylases differ between these two species, they share a common function in supporting fatty acid alpha-oxidation; that is, the oxidative ...200919575369
non-modular polyketide synthases in myxobacteria.myxobacteria are prolific producers of a wide variety of secondary metabolites. the vast majority of these compounds are complex polyketides which are biosynthesised by multimodular polyketide synthases (pkss). in contrast, few myxobacterial metabolites isolated to date are derived from non-modular pkss, in particular type iii pkss. this review reports our progress on the characterisation of type iii pkss in myxobacteria. we also summarize current knowledge on bacterial type iii pkss, with a spe ...200919586645
functional equivalence of hmga- and histone h1-like domains in a bacterial transcriptional factor.histone h1 and high-mobility group a (hmga) proteins compete dynamically to modulate chromatin structure and regulate dna transactions in eukaryotes. in prokaryotes, hmga-like domains are known only in myxococcus xanthus card and its stigmatella aurantiaca ortholog. these have an n-terminal module absent in hmga that interacts with carg (a zinc-associated factor that does not bind dna) to form a stable complex essential in regulating multicellular development, light-induced carotenogenesis, and ...200919666574
molecular and structural basis of metabolic diversity mediated by prenyldiphosphate converting enzymes.general thermodynamic calculations using the semiempiric pm3 method have led to the conclusion that prenyldiphosphate converting enzymes require at least one divalent metal cation for the activation and cleavage of the diphosphate-prenyl ester bond, or they must provide structural elements for the efficient stabilization of the intermediate prenyl cation. the most important common structural features, which guide the product specificity in both terpene synthases and aromatic prenyl transferases ...200919878958
novel expression hosts for complex secondary metabolite megasynthetases: production of myxochromide in the thermopilic isolate corallococcus macrosporus gt-2.abstract: although many secondary metabolites with diverse biological activities have been isolated from myxobacteria, most strains of these biotechnologically important gliding prokaryotes remain difficult to handle genetically. in this study we describe the new fast growing myxobacterial thermophilic isolate gt-2 as a heterologous host for the expression of natural product biosynthetic pathways isolated from other myxobacteria. according to the results of sequence analysis of the 16s rdna, thi ...200919126236
myxochelin biosynthesis: direct evidence for two- and four-electron reduction of a carrier protein-bound thioester.microorganisms produce small molecules known as siderophores to scavenge iron from the environment. insight into iron acquisition in myxobacteria has been provided recently by the sequencing of the gene cluster for the catecholate myxochelins a and b, from the myxobacterium stigmatella aurantiaca sg a15. the gene cluster contains enzymes (mxccdef) for assembly of 2,3-dihydroxybenzoic acid (dhba), an amino transferase, mxcl, and a nonribosomal peptide synthetase (nrps) subunit, mxcg. in the propo ...200818498160
efficient transfer of two large secondary metabolite pathway gene clusters into heterologous hosts by transposition.horizontal gene transfer by transposition has been widely used for transgenesis in prokaryotes. however, conjugation has been preferred for transfer of large transgenes, despite greater restrictions of host range. we examine the possibility that transposons can be used to deliver large transgenes to heterologous hosts. this possibility is particularly relevant to the expression of large secondary metabolite gene clusters in various heterologous hosts. recently, we showed that the engineering of ...200818701643
dkxanthene biosynthesis--understanding the basis for diversity-oriented synthesis in myxobacterial secondary metabolism.the dkxanthenes are a family of yellow pigments which play a critical role in myxobacterial development. thirteen unique structures from myxococcus xanthus dk1622 differ in the length of their characteristic polyene functionality, as well as the extent of methyl branching. we aimed to understand the mechanistic basis for this "molecular promiscuity" by analyzing the gene cluster in dk1622, and comparing it to the dkxanthene biosynthetic locus in a second myxobacterium, stigmatella aurantiaca dw4 ...200818721748
myxochromide b3, a new member of the myxochromide family of secondary metabolites.myxochromides are cyclic depsipeptides with an unsaturated polyketide side chain, which have been reported from different myxobacterial species, e.g., myxococcus xanthus and stigmatella aurantiaca. to date, myxochromides are subdivided into the groups a and s, according to their peptidic core structure. the peptide moiety of the new myxochromide b3 (1), which was isolated from a myxobacterial strain of the genus myxococcus, differs from that of myxochromides a and s. compound 1 thus is the first ...200818803421
eukaryotic-like protein kinases in the prokaryotes and the myxobacterial kinome.ser/thr/tyr kinases, which together comprise a major class of regulatory proteins in eukaryotes, were not believed to play an important role in prokaryotes until recently. however, our analysis of 626 prokaryotic genomes reveals that eukaryotic-like protein kinases (elks) are found in nearly two-thirds of the sequenced strains. we have identified 2697 elks, most of which are encoded by multicellular strains of the phyla proteobacteria (myxococcales), actinobacteria, cyanobacteria, and chloroflex ...200818836084
isolation and biosynthesis of aurachin p and 5-nitroresorcinol from stigmatella erecta.the isolation of aurachin p (2) from stigmatella erecta strain pd e32 is described. spectroscopic data, in particular nmr data, indicate it is 1'-hydroxyaurachin a with a 1'r,2's,3'r relative configuration. in addition, a further compound, 5-nitroresorcinol (4a), was isolated and identified as a novel natural product. feeding of (13)c- and (15)n-labeled precursors indicated this was synthesized solely from glucose and ammonia. to account for the labeling pattern, phloroglucinol (8) is postulated ...200818986196
biosynthesis of aurachins a-l in stigmatella aurantiaca: a feeding study.the isolation of aurachins a-l (1-11) from stigmatella aurantiaca strain sg a15 is described. their structures and relative configurations were deduced from spectroscopic data, in particular nmr. three structural types were identified: a-type aurachins (1, 2, 6) are c-3 oxygen-substituted quinolines carrying a farnesyl residue on c-4, c-type aurachins (3, 4, 7-11) are c-4 oxygen-substituted quinolines carrying a farnesyl residue on c-3, and c-type aurachin e (5) has a [1,1a,8,d]imidazoloquinolin ...200818989924
a quinoline antibiotic from rhodococcus erythropolis jcm 6824.a new quinoline antibiotic, aurachin re, was isolated and identified from a culture broth of rhodococcus erythropolis jcm 6824. the aurachin re structure was determined based on nmr and mass spectrometric analysis. the structure is similar to that of aurachin c antibiotics that have been identified from stigmatella aurantiaca. compared to aurachin c, however, aurachin re exhibits a wide and strong antimicrobial spectrum against both high- and low-gc gram-positive bacteria.200819168983
mutasynthesis-derived myxalamids and origin of the isobutyryl-coa starter unit of myxalamid b.myxalamids are potent inhibitors of the eukaryotic electron transport chain produced by different myxobacteria. here, we describe the identification of the myxalamid biosynthesis gene cluster from myxococcus xanthus. additionally, new myxalamids (5-13) have been obtained by mutasynthesis from bkd mutants of m. xanthus and stigmatella aurantiaca. moreover, as these bkd mutants are still able to produce myxalamid b (2), the origin of the isobutyryl-coa (ib-coa) starter unit required for its biosyn ...200717955482
evolutionary diversity of ketoacyl synthases in cellulolytic myxobacterium sorangium.the diversity of type i polyketide synthases (pkss) in cellulolytic myxobacterium sorangium was explored by assaying the ketoacyl synthases (kss) in 10 sorangium strains with two degenerate primer sets and 64 different ks fragments were obtained. for their deduced amino acid sequences, eight were identical to three known kss from sorangium and magnetospirillum, while the others showed 54-83% identities to the modular ks domains reported from various microorganisms. parts of the sorangium kss tig ...200716899349
a type ii polyketide synthase from the gram-negative bacterium stigmatella aurantiaca is involved in aurachin alkaloid biosynthesis. 200717335090
from genetic diversity to metabolic unity: studies on the biosynthesis of aurafurones and aurafuron-like structures in myxobacteria and streptomycetes.the myxobacterial polyketide secondary metabolites aurafuron a and b were identified by genome mining in the myxobacterial strain stigmatella aurantiaca dw4/3-1. the compounds contain an unusual furanone moiety and resemble metabolites isolated from soil-dwelling and marine actinobacteria, a fungus and mollusks. we describe here the cloning and functional analysis of the aurafuron biosynthetic gene cluster, including site-directed mutagenesis and feeding studies using labeled precursors. the pol ...200717919655
integration into the phage attachment site, attb, impairs multicellular differentiation in stigmatella aurantiaca.stigmatella aurantiaca displays a complex developmental life cycle in response to starvation conditions that results in the formation of tree-like fruiting bodies capable of producing spores. the phage mx8, first isolated from the close relative myxococcus xanthus, is unable to infect s. aurantiaca cells and integrate into the genome. however, plasmids containing mx8 fragments encoding the integrase and attp are able to integrate at the attb locus in the s. aurantiaca genome by site-specific rec ...200616484181
nonribosomal peptide biosynthesis: point mutations and module skipping lead to chemical diversity. 200616506259
a unique mechanism for methyl ester formation via an amide intermediate found in myxobacteria.secondary metabolism involves a broad diversity of biochemical reactions that result in a wide variety of biologically active compounds. terminal amide formation during the biosynthesis of the myxobacterial electron-transport inhibitor, myxothiazol, was analyzed by heterologous expression of the unique nonribosomal-peptide synthetase, mtag, and incubation with a synthesized substrate mimic. these experiments provide evidence that the terminal amide is formed from a carrier protein-bound myxothia ...200616807964
reconstitution of the myxothiazol biosynthetic gene cluster by red/et recombination and heterologous expression in myxococcus xanthus.although many secondary metabolites exhibiting important pharmaceutical and agrochemical activities have been isolated from myxobacteria, most of these microorganisms remain difficult to handle genetically. to utilize their metabolic potential, heterologous expression methodologies are currently being developed. here, the red/et recombination technology was used to perform all required gene cluster engineering steps in escherichia coli prior to the transfer into the chromosome of the heterologou ...200616997979
biosynthesis of iso-fatty acids in myxobacteria.the fatty acid (fa) profiles of the myxobacteria stigmatella aurantiaca and myxococcus xanthus were investigated by acidic methanolysis of total cell extracts and gc or gc-ms analysis. the main components were 13-methyltetradecanoic acid (iso-15:0) and (z)-hexadec-11-enoic acid (16:1, omega-5 cis). the biosynthesis of iso-fas was investigated in several feeding experiments. feeding of isovaleric acid (iva) to a mutant impaired in the degradation of leucine to isovaleryl-coa (iv-coa)(bkd mutant) ...200516032360
structure and biosynthesis of myxochromides s1-3 in stigmatella aurantiaca: evidence for an iterative bacterial type i polyketide synthase and for module skipping in nonribosomal peptide biosynthesis.the myxobacterium stigmatella aurantiaca dw4/3-1 harbours an astonishing variety of secondary metabolic gene clusters, at least two of which were found by gene inactivation experiments to be connected to the biosynthesis of previously unknown metabolites. in this study, we elucidate the structures of myxochromides s1-3, novel cyclic pentapeptide natural products possessing unsaturated polyketide side chains, and identify the corresponding biosynthetic gene locus, made up of six nonribosomal pept ...200515651040
novel insights into siderophore formation in myxobacteria.the myxochelins are catecholate-type siderophores produced by a number of myxobacterial strains, and their corresponding biosynthetic gene clusters have been identified in stigmatella aurantiaca sg a15, and sorangium cellulosum so ce56; the latter being presented in this work. biochemical and genetic studies described here further clarify myxochelin biosynthesis. in addition to the myxochelin a biosynthetic complex, the aminotransferase mxcl is required in order to form myxochelin b, starting fr ...200515678426
the pyruvate kinase of stigmatella aurantiaca is an indole binding protein and essential for development.myxospore formation of the myxobacterium stigmatella aurantiaca can be uncoupled from the cooperative development i.e. fruiting body formation, by low concentrations of indole. two putative indole receptor proteins were isolated by their capacity to bind indole and identified as pyruvate kinase (pk) and aldehyde dehydrogenase. the pk activity of stigmatella crude extracts was stimulated by indole. cloning of the pk gene (pyka) and the construction of a pyka disruption mutant strikingly revealed ...200515882428
a novel type of geosmin biosynthesis in myxobacteria.the biosynthesis of geosmin (1) and (1(10)e,5e)-germacradien-11-ol (2), two volatile terpenoid compounds emitted by the myxobacteria myxococcus xanthus and stigmatella aurantiaca, was investigated in feeding experiments with different labeled precursors. in these experiments, the volatiles released by the cell cultures grown on agar plates were collected with a closed-loop stripping apparatus (clsa) and analyzed by gc-ms. [(2)h(10)]leucine and [4,4,4,5,5,5-(2)h(6)]dimethylacrylate were fed to wi ...200515960521
a biosynthetic pathway to isovaleryl-coa in myxobacteria: the involvement of the mevalonate pathway.a biosynthetic shunt pathway branching from the mevalonate pathway and providing starter units for branched-chain fatty acid and secondary metabolite biosynthesis has been identified in strains of the myxobacterium stigmatella aurantiaca. this pathway is upregulated when the branched-chain alpha-keto acid dehydrogenase gene (bkd) is inactivated, thus impairing the normal branched-chain amino acid degradation process. we previously proposed that, in this pathway, isovaleryl-coa is derived from 3, ...200515619721
aurafuron a and b, new bioactive polyketides from stigmatella aurantiaca and archangium gephyra (myxobacteria). fermentation, isolation, physico-chemical properties, structure and biological activity.new antibiotic polyketides, named aurafuron a (1) and b (2) were isolated from culture extracts of myxobacteria of the species stigmatella aurantiaca and archangium gephyra, strain ar 10844. by multi-step chromatography 1 and 2 were separated from a variety of other non-related co-metabolites, and their structures elucidated by spectroscopic methods as new 5-alkenyl-3 3(2h)-furanones. aurafurons inhibited the growth of some filamentous fungi and additionally, aurafuron b was weakly active agains ...200515981410
biosynthesis of iso-fatty acids in myxobacteria: iso-even fatty acids are derived by alpha-oxidation from iso-odd fatty acids.the biosynthesis of iso-fatty acids was investigated in the myxobacteria myxococcus xanthus and stigmatella aurantiaca by feeding labeled precursors of these fatty acids and by conducting detailed analysis of the fatty acid profiles and fatty acid ms and nmr spectra. these experiments revealed that in s. aurantiaca all iso-even fatty acids are formed via alpha-oxidation of iso-odd fatty acids and not by using valine-derived isobutyryl-coa.200515643871
biosynthesis and identification of volatiles released by the myxobacterium stigmatella aurantiaca.the volatiles released by agar plate cultures of two strains of the myxobacterium stigmatella aurantiaca (strains sg a15 and dw4/3-1) were collected in a closed-loop stripping apparatus (clsa) and analyzed by gc-ms. large numbers of substances from different compound classes (ketones, esters, lactones, terpenes, and sulfur and nitrogen compounds) were identified; several of them are reported from natural sources for the first time. the volatiles 2-methyltridecan-4-one (17), its isomer 3-methyltr ...200516208730
exploiting pseudomonas putida for drug development.in this issue of chemistry & biology, a strategy that combines large dna fragment recombineering in escherichia coli and heterologous expression in pseudomonas putida is described. the work focuses on myxochromide s, a natural compound produced by stigmatella aurantiaca.200515797207
heterologous expression of a myxobacterial natural products assembly line in pseudomonads via red/et recombineering.natural products of microbial origin are widely used as pharmaceuticals and in agrochemistry. these compounds are often biosynthesized by multifunctional megasynthetases whose genetic engineering and heterologous expression offer considerable promise, especially if the natural hosts are genetically difficult to handle, slow growing, unculturable, or even unknown. we describe a straightforward strategy that combines the power of advanced dna engineering (recombiogenic cloning) in escherichia coli ...200515797219
signaling in myxobacteria.myxobacteria use soluble and cell-contact signals during their starvation-induced formation of fruiting bodies. these signals coordinate developmental gene expression with the cell movements that build fruiting bodies. early in development, the quorum-sensing a-signal in myxococcus xanthus helps to assess starvation and induce the first stage of aggregation. later, the morphogenetic c-signal helps to pattern cell movement and shape the fruiting body. c-signal is a 17-kda cell surface protein tha ...200415487930
the csbx gene of azotobacter vinelandii encodes an mfs efflux pump required for catecholate siderophore export.the csbx gene of azotobacter vinelandii was regulated in an iron-repressible manner from a divergent promoter upstream of the catecholate siderophore biosynthesis (csb) operon and was predicted to encode an efflux pump of the major facilitator superfamily. other proteins that were most similar to csbx were encoded by genes found in the catecholate siderophore biosynthesis operons of aeromonas hydrophila and stigmatella aurantiaca. inactivation of csbx resulted in 57-100% decrease in the amount o ...200314638426
a defined subset of adenylyl cyclases is regulated by bicarbonate ion.the molecular basis by which organisms detect and respond to fluctuations in inorganic carbon is not known. the cyab1 gene of the cyanobacterium anabaena sp. pcc7120 codes for a multidomain protein with a c-terminal class iii adenylyl cyclase catalyst that was specifically stimulated by bicarbonate ion (ec50 9.6 mm). bicarbonate lowered substrate affinity but increased reaction velocity. a point mutation in the active site (lys-646) reduced activity by 95% and was refractory to bicarbonate activ ...200312829712
solubilization and refolding of inclusion body proteins in reverse micelles.today, many valuable proteins can be obtained in sufficient amounts using recombinant dna techniques. however, frequently the expression of recombinant proteins results in the accumulation of the product in dense amorphous deposits inside the cells, called inclusion bodies. the challenge then is to transform these inactive and misfolded protein aggregates into soluble bioactive forms. although a number of general guidelines have been proposed, the search for proper reconstitution conditions can ...200312927829
steroid biosynthesis in prokaryotes: identification of myxobacterial steroids and cloning of the first bacterial 2,3(s)-oxidosqualene cyclase from the myxobacterium stigmatella aurantiaca.steroids, such as cholesterol, are synthesized in almost all eukaryotic cells, which use these triterpenoid lipids to control the fluidity and flexibility of their cell membranes. bacteria rarely synthesize such tetracyclic compounds but frequently replace them with a different class of triterpenoids, the pentacyclic hopanoids. the intriguing mechanisms involved in triterpene biosynthesis have attracted much attention, resulting in extensive studies of squalene-hopene cyclase in bacteria and (s) ...200312519197
the stigmatella aurantiaca homolog of myxococcus xanthus high-mobility-group a-type transcription factor card: insights into the functional modules of card and their distribution in bacteria.transcriptional factor card is the only reported prokaryotic analog of eukaryotic high-mobility-group a (hmga) proteins, in that it has contiguous acidic and at hook dna-binding segments and multifunctional roles in myxococcus xanthus carotenogenesis and fruiting body formation. hmga proteins are small, randomly structured, nonhistone, nuclear architectural factors that remodel dna and chromatin structure. here we report on a second at hook protein, card(sa), that is very similar to card and tha ...200312775690
melithiazol biosynthesis: further insights into myxobacterial pks/nrps systems and evidence for a new subclass of methyl transferases. 200314583260
markerless mutations in the myxothiazol biosynthetic gene cluster: a delicate megasynthetase with a superfluous nonribosomal peptide synthetase domain. 200314583261
the biosynthesis of the aromatic myxobacterial electron transport inhibitor stigmatellin is directed by a novel type of modular polyketide synthase.deductions from the molecular analysis of the 65,000-bp stigmatellin biosynthetic gene cluster are reported. the biosynthetic genes (stia-j) encode an unusual bacterial modular type i polyketide synthase (pks) responsible for the formation of this aromatic electron transport inhibitor produced by the myxobacterium stigmatella aurantiaca. involvement of the pks gene cluster in stigmatellin biosynthesis is shown using site-directed mutagenesis. one module of the pks is assumed to be used iterative ...200211809757
a novel biosynthetic pathway providing precursors for fatty acid biosynthesis and secondary metabolite formation in myxobacteria.short chain carboxylic acids are well known as the precursors of fatty acid and polyketide biosynthesis. iso-fatty acids, which are important for the control of membrane fluidity, are formed from branched chain starter units (isovaleryl-coa and isobutyryl-coa), which in turn are derived from the degradation of leucine and valine, respectively. branched chain carboxylic acids are also employed as starter molecules for the biosynthesis of secondary metabolites, e.g. the therapeutically important a ...200212084727
multiple hybrid polyketide synthase/non-ribosomal peptide synthetase gene clusters in the myxobacterium stigmatella aurantiaca.many bacterial and fungal secondary metabolites are produced by polyketide synthases (pks) and non-ribosomal peptide synthetases (nrps). recently, it has been discovered that these modular enzymatic systems can also closely cooperate to form natural products. the analysis of the corresponding biosynthetic machineries, in the form of hybrid systems, is of special interest for combinatorial biosynthesis, because the combination of pks and nrps can lead to an immense variety of structures that migh ...200111587850
the mtaa gene of the myxothiazol biosynthetic gene cluster from stigmatella aurantiaca dw4/3-1 encodes a phosphopantetheinyl transferase that activates polyketide synthases and polypeptide synthetases.myxothiazol is synthesized by the myxobacterium stigmatella aurantiaca dw4/3-1 via a combined polyketide synthase/polypeptide synthetase. the biosynthesis of this secondary metabolite is also dependent on the gene product of mtaa. the deduced amino acid sequence of mtaa shows similarity to 4'-phosphopantetheinyl transferases (4'-pp transferase). this points to an enzyme activity that converts inactive forms of the acyl carrier protein domains of polyketide synthetases (pkss) and/or the peptidyl ...200111134965
novel features in a combined polyketide synthase/non-ribosomal peptide synthetase: the myxalamid biosynthetic gene cluster of the myxobacterium stigmatella aurantiaca sga15.myxobacteria have been well established as a potent source for natural products with biological activity. they produce a considerable variety of compounds which represent typical polyketide structures with incorporated amino acids (e.g. the epothilons, the myxothiazols and the myxalamids). several of these secondary metabolites are effective inhibitors of the electron transport via the respiratory chain and have been widely used. molecular cloning and characterization of the genes governing the ...200111182319
sigb, an alternative sigma factor of the myxobacterium stigmatella aurantiaca, is synthesized during development and heat shock.alternative sigma factors have been detected in the myxobacterium stigmatella aurantiaca during indole-induced sporulation, fruiting body formation and heat shock using an antiserum raised against sigma factor sigb. the time course of sigb gene expression was analysed by rt-pcr and by determining beta-galactosidase activity during development in a merodiploid strain that harboured a sigb-lacz fusion gene. inactivation of the sigb gene by insertion of the neo gene resulted in the loss of one sigm ...200111496003
in vitro reconstitution of the myxochelin biosynthetic machinery of stigmatella aurantiaca sg a15: biochemical characterization of a reductive release mechanism from nonribosomal peptide synthetases.microorganisms produce iron-chelating compounds to sequester the iron essential for growth from the environment. many of these compounds are biosynthesized by nonribosomal peptide synthetases, some in cooperation with polyketide synthases. myxochelins are produced by the myxobacterium stigmatella aurantiaca sg a15, and the corresponding gene cluster was cloned recently. we have undertaken to express heterologously the myxochelin biosynthetic machinery in escherichia coli. to activate the involve ...200111562468
initiation factor 2 of myxococcus xanthus, a large version of prokaryotic translation initiation factor 2.we have isolated the structural gene for translation initiation factor if2 (infb) from the myxobacterium myxococcus xanthus. the gene (3.22 kb) encodes a 1,070-residue protein showing extensive homology within its g domain and c terminus to the equivalent regions of if2 from escherichia coli. the protein cross-reacts with antibodies raised against e. coli if2 and was able to complement an e. coli infb mutant. the m. xanthus protein is the largest if2 known to date. this is essentially due to a l ...200111114918
the myxochelin iron transport regulon of the myxobacterium stigmatella aurantiaca sg a15.the biosynthetic gene cluster of the myxochelin-type iron chelator was cloned from stigmatella aurantiaca sg a15 and characterized. this catecholate siderophore was only known from two other myxobacteria. the biosynthetic genes of 2,3-dihydroxybenzoic acid are located in the cluster (mxcc-mxcf). two molecules of 2, 3-dihydroxybenzoic acid are activated and condensed with lysine in a unique way by a protein homologous to nonribosomal peptide synthetases (mxcg). inactivation of mxcg, which encodes ...200011029592
diastereo- and enantioselective total synthesis of stigmatellin a.stigmatellin a (1) isolated from the myxobacterium stigmatella aurantiaca is a powerful inhibitor of electron transport in mitochondria and chloroplasts. the first highly diastereo- and enantioselective total synthesis of this important natural product is described. key steps in the synthesis are the alkylation of the samp-hydrazone (s)-13, a titanium mediated syn-diastereoselective aldol reaction, the anti-diastereoselective triacetoxyborohydride reduction of the aldol adduct (r,r,s)-16, format ...200010840951
stigmatella aurantiaca sg a15 carries genes encoding type i and type ii 3-deoxy-d-arabino-heptulosonate-7-phosphate synthases: involvement of a type ii synthase in aurachin biosynthesis.3-deoxy-d-arabino-heptulosonate-7-phosphate (dahp) synthases catalyse the first step of the shikimate pathway. two unrelated dahp synthase types have been described in plants and bacteria. two type ii (aroa(a2) and aroa(a5)) and one type i dahp synthase gene (aroa001) were identified from the myxobacterium stigmatella aurantiaca sg a15. inactivation of aroa(a5) leads to a mutant that is impaired in the biosynthesis of aurachins, which are electron transport inhibitors and contain an anthranilate ...200010896221
purification of cold-shock-like proteins from stigmatella aurantiaca - molecular cloning and characterization of the cspa gene.prominent low-molecular-weight proteins were isolated from vegetative cells of the myxobacterium stigmatella aurantiaca and were found to be members of the cold-shock protein family. a first gene of this family (cspa) was cloned and sequenced. it encodes a protein of 68 amino acid residues that displays up to 71% sequence identity with other bacterial cold-shock(-like) proteins. a cysteine residue within the rnp-2 motif is a peculiarity of stigmatella cspa. a cspa::(deltatrp-lacz) fusion gene co ...199910460888
new lessons for combinatorial biosynthesis from myxobacteria. the myxothiazol biosynthetic gene cluster of stigmatella aurantiaca dw4/3-1.the biosynthetic mta gene cluster responsible for myxothiazol formation from the fruiting body forming myxobacterium stigmatella aurantiaca dw4/3-1 was sequenced and analyzed. myxothiazol, an inhibitor of the electron transport via the bc(1)-complex of the respiratory chain, is biosynthesized by a unique combination of several polyketide synthases (pks) and nonribosomal peptide synthetases (nrps), which are activated by the 4'-phosphopantetheinyl transferase mtaa. genomic replacement of a fragme ...199910601310
intercellular signalling in stigmatella aurantiaca.the myxobacterium stigmatella aurantiaca is a prokaryotic model used to study intercellular signalling and the genetic determination of morphogenesis. signalling factors and genes required for the generation of the elaborate multicellular fruiting body are to be identified. recently, the structure of stigmolone, which is the pheromone necessary for fruiting body formation, was elucidated, and genes involved in development were characterised. progress has also been made in the genetic accessibili ...199910607625
the correlation between morphological and phylogenetic classification of myxobacteria.in order to determine whether morphological criteria are suitable to affiliate myxobacterial strains to species, a phylogenetic analysis of 16s rdnas was performed on 54 myxobacterial strains that represented morphologically 21 species of the genera angiococcus, archangium, chondromyces, cystobacter, melittangium, myxococcus, polyangium and stigmatella, five invalid species and three unclassified isolates. the analysis included 12 previously published sequences. the branching pattern confirmed t ...199910425789
metabolic diversity in myxobacteria: identification of the myxalamid and the stigmatellin biosynthetic gene cluster of stigmatella aurantiaca sg a15 and a combined polyketide-(poly)peptide gene cluster from the epothilone producing strain sorangium cellulosum so ce90.myxobacterial strains producing polyketides (pks) assumed to be biosynthesized by a type i polyketide synthase (pks) were analysed. myxobacteria also produce a variety of polypeptides (pp) and pks with incorporated amino acids ('mixed pk-pp'). in order to be able to identify the biosynthetic gene clusters for these metabolites a pcr based approach has been developed to clone ketosynthase (ks) domains of pks genes from these organisms. conserved regions of peptide synthetases of the non-ribosomal ...199910320771
structure elucidation and chemical synthesis of stigmolone, a novel type of prokaryotic pheromone.approximately 2 micromol of a novel prokaryotic pheromone, involved in starvation-induced aggregation and formation of fruiting bodies by the myxobacterium stigmatella aurantiaca, were isolated by a large-scale elution procedure. the pheromone was purified by hplc, and high-resolution ms, ir, 1h-nmr, and 13c-nmr were used to identify the active substance as the hydroxy ketone 2,5, 8-trimethyl-8-hydroxy-nonan-4-one, which has been named stigmolone. the analysis was complicated by a solvent-depend ...19989736725
independent patterns of expression of two alternative sigma factors, sigb and sigc, of the myxobacterium stigmatella aurantiaca during development.the transcription of many spatially and temporally controlled developmental genes is required for cellular differentiation of the myxobacterium stigmatella aurantiaca. the expression patterns of the sigma factor gene sigb and of a novel alternative sigma factor gene sigc have been studied during development of stigmatella aurantiaca. they are expressed at different stages of development. sigb is expressed from the very beginning of fruiting body formation to the sporulation step, while sigc expr ...19989700054
fbfb, a gene encoding a putative galactose oxidase, is involved in stigmatella aurantiaca fruiting body formation.stigmatella aurantiaca is a gram-negative bacterium which forms, under conditions of starvation in a multicellular process, characteristic three-dimensional structures: the fruiting bodies. for studying this complex process, mutants impaired in fruiting body formation have been induced by transposon insertion with a tn5-derived transposon. the gene affected (fbfb) in one of the mutants (ap182) was studied further. inactivation of fbfb results in mutants which form only clumps during starvation i ...19989495764
intercellular signaling in stigmatella aurantiaca: purification and characterization of stigmolone, a myxobacterial pheromone.the myxobacterium stigmatella aurantiaca passes through a life cycle that involves formation of a multicellular fruiting body as the most complex stage. an early step in this differentiation process depends on a signal factor secreted by the cells when nutrients become limited. the formation of a fruiting body from a small cell population can be accelerated by addition of this secreted material. the bioactive compound was found to be steam volatile. it was purified to homogeneity by steam distil ...19989736724
translation initiation factor if2 of the myxobacterium stigmatella aurantiaca: presence of a single species with an unusual n-terminal sequence.the structural gene for translation initiation factor if2 (infb) was isolated from the myxobacterium stigmatella aurantiaca on a 5.18-kb bamhi genomic restriction fragment. the infb gene (ca. 3.16 kb) encodes a 1,054-residue polypeptide with extensive homology within its g domain and c terminus with the equivalent regions of if2s from escherichia coli, bacillus subtilis, bacillus stearothermophilus, and streptococcus faecium. the n-terminal region does not display any significant homology to oth ...19979079922
bifunctional structure of two adenylyl cyclases from the myxobacterium stigmatella aurantiaca.two adenylyl cyclase genes (cyaa and cyab) from the myxobacterium stigmatella aurantiaca were cloned by complementation of escherichia coli mutants defective in the cya gene. cyaa codes for a protein of 424 amino acid residues (ac1), while cyab encodes a protein of 352 residues (ac2). both cyclases are sensitive to adenosine: camp production was strongly inhibited in e coli cells and cell extracts expressing these genes. ac1 comprises a hydrophobic domain of six transmembrane helices coupled to ...19979523018
stigmatella aurantiaca fruiting body formation is dependent on the fbfa gene encoding a polypeptide homologous to chitin synthases.stigmatella aurantiaca is a prokaryotic organism that undergoes a multicellular cycle of development resulting in the formation of a fruiting body. for analyzing this process, mutants defective in fruiting body formation have been induced by transposon mutagenesis using a tn5-derived transposon. about 800 bp upstream of the transposon insertion of mutant ap182 which inactivates a gene (fbfb) involved in fruiting, a further gene (fbfa) needed for fruiting body formation was detected. inactivation ...19968955286
the effects of decyl aurachins c and d on the respiratory electron flow of facultative phototrophic bacteria.decyl aurachins c and d are two synthetic compounds related to the natural products aurachins c and d extracted from stigmatella aurantiaca. titrations of a range of partial respiratory activities in membranes from facultative phototrophs indicate that decyl aurachin c is more effective than aurachin d in inhibiting the quinol oxidase. decyl aurachin c also affects the nadh-ubiquinone oxidoreductase of rhodobacter capsulatus and the cytochrome bc1 complexes of rb.capsulatus and rhodospirillum ce ...19968843334
localization of the stress protein sp21 in indole-induced spores, fruiting bodies, and heat-shocked cells of stigmatella aurantiaca.the localization and distribution of the stress protein sp21 in indole-induced vegetative cells, fruiting bodies, and heat shocked cells of stigmatella aurantiaca were determined by immunoelectron microscopy. sp21 was found at the cell periphery in heat-shocked cells and either at the cell periphery or within the cytoplasm in indole-induced cells, often concentrated in clusters. in fruiting-body-derived spores, sp21 was located mainly at the cell wall, preferentially at the outer periphery. furt ...19958522514
genetic and molecular analysis of the trna-tufb operon of the myxobacterium stigmatella aurantiaca.the tufb gene, encoding elongation factor tu (ef-tu), from the myxobacterium stigmatella aurantiaca was cloned and sequenced. it is preceded by four trna genes, the first ever described in myxobacteria. the trna synthesized from these genes and the general organization of the locus seem identical to that of escherichia coli, but differences of potential importance were found in the trna sequences and in the intergenic regions. the primary structure of ef-tu was deduced from the tufb dna sequence ...19957784178
the gene encoding the beta-1,4-endoglucanase (cela) from myxococcus xanthus: evidence for independent acquisition by horizontal transfer of binding and catalytic domains from actinomycetes.the cela gene encoding a beta-1,4 endoglucanase (cela) from myxococcus xanthus has been cloned in escherichia coli and sequenced. the c-terminal region of cela displayed a high level of similarity with the catalytic domain of several egl belonging to the glycosyl hydrolases family 6 (cena from cellulomonas fimi, cela from microbispora bispora, e2 from thermonospora fusca, casa from streptomyces ksm9 and cela1 from streptomyces halstedii) and less similarity to the cellobiohydrolases of the fungi ...19957789807
an endo-n-acetyl-beta-d-glucosaminidase, acting on the di-n-acetylchitobiosyl part of n-linked glycans, is secreted during sporulation of myxococcus xanthus.after the demonstration that stigmatella aurantiaca dw4 secretes an endo-n-acetyl-beta-d-glucosaminidase (engase), acting on the di-n-acetylchitobiosyl part of n-linked glycans (s. bourgerie, y. karamanos, t. grard, and r. julien, j. bacteriol. 176:6170-6174, 1994), an engase activity having the same substrate specificity was also found to be secreted during vegetative growth of myxococcus xanthus dk1622. the activity decreased in mutants known to secrete less protein than the wild type (exc +/- ...19957860600
phylogenetic comparison of retron elements among the myxobacteria: evidence for vertical inheritance.twenty-eight myxobacterial strains, representing members from all three subgroups, were screened for the presence of retron elements, which are novel prokaryotic retroelements encoding reverse transcriptase. the presence of retrons was determined by assaying strains for a small satellite dna produced by reverse transcription called multicopy, single-stranded dna (msdna). an msdna-producing retron appeared to be absent from only one of the strains surveyed. dna hybridization experiments revealed ...19957798147
purification and characterization of an endo-n-acetyl-beta-d-glucosaminidase from the culture medium of stigmatella aurantiaca dw4.a novel endo-n-acetyl-beta-d-glucosaminidase (engase), acting on the di-n-acetylchitobiosyl part of n-linked glycans, was characterized in the culture medium of stigmatella aurantiaca dw4. purified to homogeneity by ammonium sulfate precipitation, gel filtration, and chromatofocusing, this engase presents, upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a molecular mass near 27 kda. optimal ph and pi were 4.0 and 6.8, respectively. the enzyme, named engase st, exhibits high activ ...19947928985
isolated fibrils rescue cohesion and development in the dsp mutant of myxococcus xanthus.extracellular fibrils are involved in cell cohesion and cell development in myxococcus xanthus. one group of social motility mutants, dsp, is unable to produce extracellular fibrils; these mutants also lose the abilities to cohere and to develop. extracellular fibrils isolated from vegetative wild-type cells and added to dsp cells fully restored the abilities of these cells to cohere and to undergo normal morphological development. the fibrils thus mimic the ability of intact, wild-type cells to ...19947961490
territorial interactions between two myxococcus species.it is unusual to find fruiting bodies of different myxobacteria occupying the same territory on natural samples. we were thus interested in determining whether myxobacteria establish territorial dominance and, if so, what the mechanism of that interaction is. we had previously observed that vegetative swarms of myxococcus xanthus and stigmatella aurantiaca placed close to each other on an agar surface initially merged but eventually separated. further studies indicated that these two species als ...19948106334
stimulation of inositide degradation in clumping stigmatella aurantiaca.numerous external signals which activate inositol phospholipid hydrolysis in eukaryotes are known; probably all of these signals are transduced by g proteins. so far, neither signal-transducing g protein nor receptor-regulated phospholipase c has been found in prokaryotes. however, a group of bacteria, the myxobacteria, displays cellular and tissue-like differentiation; therefore, it appeared that a search for the various activities involved in a signal-activated phosphatidylinositol cycle might ...19948113179
cloning and characterization of the gene encoding the major sigma factor of stigmatella aurantiaca.the gene (siga) encoding the major sigma factor of the myxobacterium, stigmatella aurantiaca, was cloned and sequenced. the deduced polypeptide contains 706 amino acids (aa) and has a deduced m(r) of 79,910. it exhibits four different aa sequence motifs which correlate with the conserved domains of the major sigma factors of myxococcus xanthus (sigma 80), escherichia coli (sigma 70) and bacillus subtilis (sigma 43). the sigma factor (sigma a) was detected in crude lysates of vegetative cells and ...19948200526
heat shock and development induce synthesis of a low-molecular-weight stress-responsive protein in the myxobacterium stigmatella aurantiaca.in the fruiting body-forming myxobacterium stigmatella aurantiaca a 21,000-m(r) protein, sp21, is synthesized during fruiting, heat shock, and stress induced by oxygen limitation. the corresponding gene was isolated from a gene expression library in lambda gt11 with an antiserum to the purified protein. the dna sequence of the gene reveals that sp21 is a member of the alpha-crystallin family of low-molecular-weight heat shock proteins.19938226695
purification and characterization of sp21, a development-specific protein of the myxobacterium stigmatella aurantiaca.stigmatella aurantiaca is a gram-negative bacterium with a complex life cycle, including cellular aggregation resulting in the formation of a characteristic three-dimensional structure, the so-called fruiting body. during fruiting and upon chemical induction of sporulation, a major development-specific protein, sp21, is synthesized. sp21 was purified to homogeneity from the membranous fraction of chemically induced spores. expression of sp21 was studied with an antiserum raised against the purif ...19938423161
selective amplification of dna fragments coding for the g domain of factors if2 and ef-tu, two g proteins from the myxobacterium stigmatella aurantiaca.two dna fragments of the genome of the myxobacterium stigmatella aurantiaca were selectively amplified by pcr. these fragments encode a segment of the g domain of translational initiation factor if2 and elongation factor ef-tu, two gtp-binding proteins. this was made possible by carefully designing the primers for this reaction to avoid the amplification of every g-domain-encoding region of the genome. the sequence of two pairs of primers was deduced from highly conserved regions, namely g1 and ...19938118402
a physical and genetic map of the stigmatella aurantiaca dw4/3.1 chromosome.a physical map of the myxobacterium stigmatella aurantiaca dw4/3.1 chromosome was constructed by pulsed-field gel (pfg) long-range mapping. one-and two-dimensional pulsed-field gel analyses were used together with reciprocal double-restriction, cross-hybridization and hybridization fingerprint analysis. these pfg results were confirmed by smith-birnstiel analysis, by southern hybridization using linking clones and clones of a lambda genomic library for the determination of adjacent restriction f ...19937934859
purification of the dna-dependent rna polymerase from the myxobacterium stigmatella aurantiaca.the dna-dependent rna polymerase (ec 2.7.7.6) of the myxobacterium stigmatella aurantiaca has been purified. it shows three main polypeptide bands with apparent molecular weights of 146,000, 105,000, and 40,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. beta and beta' subunits of the s. aurantiaca polymerase were shown to migrate in the 146,000-molecular-weight polypeptide band and the main sigma factor was shown to migrate in the 105,000-molecular-weight band by using heterol ...19921556092
cell surface modifications induced by calcium ion in the myxobacterium stigmatella aurantiaca.calcium ion induces in the myxobacterium stigmatella aurantiaca the ability to glide on solid surfaces and to become cohesive (d. f. gilmore and d. white, j. bacteriol. 161:113-117, 1985; b. j. womack, d. f. gilmore, and d. white, j. bacteriol. 171:6093-6096, 1989). the addition of calcium ion to the growth medium resulted in the formation of extracellular fibrils, the appearance in the membrane fractions of a 30-kda protein, and the accumulation in a low-speed centrifugal pellet of 10 polypepti ...19921522058
size and stability of the genomes of the myxobacteria stigmatella aurantiaca and stigmatella erecta.genomic dna of stigmatella aurantiaca dw 4/3.1 was restricted with the rare-cutting endonucleases asei and spei. the restriction pattern derived is composed of 33 asei and 25 spei fragments, whose total size amounts to approximately 9,350 kbp. genomic fingerprint analysis of chromosomal dna from several s. aurantiaca isolates further revealed five completely different spei and asei fingerprints and one distinct fingerprint for stigmatella erecta. in addition, minor variations between the genome ...19921400181
in vivo production of a stable single-stranded cdna in saccharomyces cerevisiae by means of a bacterial retron.gram-negative bacteria such as myxococcus xanthus, stigmatella aurantiaca, and escherichia coli contain retroelements called retrons. retrons consist of the msr-msd region and the gene for reverse transcriptase (rt), which are essential for the production of the branched rna-linked ms-dna (multicopy single-stranded dna). in this study, we attempted to produce msdna in the yeast saccharomyces cerevisiae. retron ec67 from e. coli, which is responsible for the production of msdna-ec67, was cloned u ...19921378616
similarity between the myxococcus xanthus and stigmatella aurantiaca reverse transcriptase genes associated with multicopy, single-stranded dna.to determine the evolutional relationship of bacterial retroelements of myxococcus xanthus and stigmatella aurantiaca, the nucleotide sequence of 3,060 bases encompassing msr, msd, and the upstream region of msd (downstream of msr) of s. aurantiaca dw4 was determined and compared with the same region from m. xanthus. an open reading frame was found 92 bases upstream of msd which encoded a polypeptide of 480 amino acid residues having 73% identity with the reverse transcriptase of m. xanthus. tog ...19921372604
cloning and dna sequence of sigb gene of stigmatella aurantiaca. 19921475207
calcium requirement for gliding motility in myxobacteria.the ability to glide on a solid surface was inducible by calcium ion in stigmatella aurantiaca. the induction of motility but not motility itself was prevented by chloramphenicol and erythromycin. calcium ion was also required for cells to glide, even when they were previously induced. the ability of myxococcus xanthus to glide in groups using the s motility system but not as single cells (a system) was prevented by chloramphenicol and erythromycin.19892509428
evidence for a membrane-associated gtp-binding protein in stigmatella aurantiaca, a prokaryotic cell.signal transducing g proteins are present in all eukaryotic cells, but they have not been found in prokaryotes so far. myxobacteria, especially stigmatella aurantiaca, are prokaryotic organisms able to exchange signals. moreover, they exhibit an active phosphoinositide metabolism, whose intensity is dependent on the physiological state of the cell. therefore g proteins potentially involved in the activation of phospholipid metabolism or any other event stimulated by external signals were looked ...19892492803
mutations that affect production of branched rna-linked msdna in myxococcus xanthus.a deletion mutation of the gene (msd-msr) for the branched rna-linked msdna of myxococcus xanthus was constructed by replacing the chromosomal 0.7-kilobase (kb) smai-xhoi fragment encompassing msd-msr with a 1.4-kb fragment carrying a gene for kanamycin resistance. it was found that this deletion strain (delta mssx) could not produce msdna, although it still contained another species of msdna, mrdna (msdna, reduced size). no apparent differences between delta mssx and the wild-type strain were o ...19882461359
transfer of incp plasmids into stigmatella aurantiaca leading to insertional mutants affected in spore development.derivatives of the broad-host-range plasmid rp4, containing the wild-type or modified transposon tn5 were transferred by conjugation to various stigmatella aurantiaca isolates. the transposons and in some cases fragments of the plasmid as well were integrated into the chromosome. thus, insertional mutants have been obtained affected in spore formation in liquid culture.19882853291
biosynthesis and structure of stable branched rna covalently linked to the 5' end of multicopy single-stranded dna of stigmatella aurantiaca.stigmatella aurantiaca, a gram-negative bacterium, contains approximately 500 copies per cell of a short single-stranded linear dna (multicopy single-stranded dna: msdna). this dna is attached to a branched rna (msdrna) by its 5' end. the entire sequence of msdrna was determined and found to consist of 76 bases. the msdna is linked at the 19th g residue of msdrna by a 2', 5' phosphodiester linkage. the coding region for msdrna (msr) is located downstream of the coding region for msdna (msd). the ...19872431795
branched rna covalently linked to the 5' end of a single-stranded dna in stigmatella aurantiaca: structure of msdna.stigmatella aurantiaca is a gliding, gram-negative bacterium that shows a spectacular fruiting body formation upon starvation of nutrient. this bacterium was found to contain approximately 500 copies per cell of a short single-stranded linear dna (multicopy single-stranded dna: msdna). the primary structure of msdna was determined and found to consist of 162 or 163 deoxyribonucleotides. its unique chromosomal gene was cloned and sequenced. the msdna was found to be attached to a branched rna by ...19872431793
the aurachins, new quinoline antibiotics from myxobacteria: production, physico-chemical and biological properties.the aurachins, new quinoline alkaloids, were extracted with acetone from the biomass of the myxobacterium, stigmatella aurantiaca strain sg a15 and purified by column chromatography. the four described aurachins a, b, c and d, were inhibitory for gram-positive bacteria and a few yeasts and molds. they blocked nadh oxidation in beef heart submitochondrial particles.19873106289
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