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native agarose-polyacrylamide gel electrophoresis allowing the detection of aminopeptidase, dehydrogenase, and esterase activities at the nanogram level: enzymatic patterns in some frankia strains.nanogram amounts of soluble aminopeptidases, dehydrogenases, and esterases were detected by nondenaturing ultralow gelling point agarose-polyacrylamide gel electrophoresis (ulga-page). cytosolic fractions from frankia sp. were electrophoresed at 4 degrees c in the presence of co2+, zn2+, or mg2+ ions. then, aminopeptidases and esterases were revealed by simultaneous capture staining by using fast garnet gbc diazonium salt as the chromogenic coupling compound. dehydrogenases were revealed by usin ...19902200309
developmental potential of frankia vesicles.the ability of nitrogenase-containing frankia sp. strain cpi1 vesicles to regrow vegetative hyphae is demonstrated. vesicles attached to hyphae in n2-fixing cpi1 cultures and sucrose gradient-isolated vesicles exhibited hyphal outgrowths when incubated in certain defined liquid media. single or multiple hyphal extensions grew out from the vesicles.19892592353
cloning of a multicopy plasmid from the actinorhizad nitrogen-fixing bacterium frankia sp. and determination of its restriction map.an 8.3-kb multicopy plasmid, pfq31, from the nitrogen-fixing frankia sp. strain ari3, was cloned into escherichia coli plasmid vectors and analysed physically. pfq31 has no detectable sequence homology with another frankia plasmid, pfq32, which is present in the same host. derivatives of pfq31 with an antibotic resistance marker were introduced into streptomyces lividans, which is taxonomically related to frankia, but no stable replication could be achieved.19852989115
evidence for adenylate nucleotide transport (atp-adp translocation) in vesicles of frankia sp. strain ean1pec.atractyloside and carboxyatractyloside partially inhibited nitrogenase activity (acetylene reduction) by isolated vesicles of frankia strain ean1pec. extracts of disrupted vesicles showed nitrogenase activity that was not affected by the inhibitors. the vesicles accumulated atp by an atractyloside-sensitive mechanism. this inhibition of atp uptake was reversed when vesicles were permeabilized by detergent. uptake of atp was inhibited by excess atp and adp, but not amp or adenosine, and by a calc ...19883164310
natural variation in symbiotic nitrogen-fixing rhizobium and frankia spp.a description is given of the natural variation in nitrogen-fixing rhizobium and frankia spp. strains and the ability to form root nodules on compatible host plants. arguments are given for the hypothesis that co-evolution has taken place through mutual interaction of host plants and indigenous rhizobium and frankia populations in the soil leading to most efficient symbiotic associations. the significance of root nodules as selective enrichment cultures of particular strains in natural and culti ...19846397130
molecular cloning and complementation analysis of nifv gene from frankia euik1 strain.the nifv gene from the frankia euik1 strain, a symbiont of elaeagnus umbellata, was cloned and a complementation test using the klebsiella pneumoniae nifv mutant was performed to verify its function. the nifv orf consists of 1245 bp, which encodes 414 amino acids. however, the putative promoter and shine-dalgarno sequences were not found in the 5' region of the orf. the frankia euik1 nifv orf showed about a 70% nucleotide identity and 80% amino acid similarity with that of frankia sp. fac1. in t ...200312661757
characterization of the sodf gene region of frankia sp. strain acn14a and complementation of escherichia coli sod mutant.the frankia sp. strain acn14a superoxide dismutase sodf was previously shown to be induced in response to alnus glutinosa root exudates, and its gene was sequenced. we report here the sequence of the 9-kb genomic segment surrounding the sodf gene and further characterize this gene and its product. nine orfs coding for various proteins, such as regulators, acetyl-coa transferases, and a bacterioferritin a next to the sodf gene, were found. northern blot analysis showed that the sodf gene was expr ...200312897839
a hydrogen-evolving enzyme is present in frankia sp. r43.the ability to evolve hydrogen using methyl viologen as an electron donor was assayed in the nitrogen-fixing actinomycetes frankia sp. r43 and frankia sp. kb5. to further examine the nature of hydrogen-evolving enzymes that may be present in these organisms immunological studies were performed. under anaerobic conditions (both nitrogen-limiting and nitrogen-containing) frankia sp. r43 but not frankia sp. kb5 evolved hydrogen,which was not linked to nad-reducing activity. immunological analysis o ...200415251202
analysis of a ribosomal rna operon in the actinomycete frankia.the organisation of ribosomal rna-encoding (rrn) genes has been studied in frankia sp. strain ors020606. the two rrn clusters present in frankia strain ors020606 were isolated from genomic banks in phage lambda embl3 by hybridization with oligodeoxyribonucleotide probes. the 5'-3' gene order is the usual one for bacteria: 16s-23s-5s. the two clusters are not distinguishable by restriction enzyme mapping inside the coding section, but vary considerably outside it. sequencing showed that the 16s-r ...19921372279
isolation of novel bacteria and actinomycetes using soil-extract agar medium.novel bacteria were discovered using an isolation technique consisting of (i) selection of microorganisms that grew on soil-extract agar medium, but not on conventional media, and (ii) detection of small microbial colonies with a microscope. three bacterial strains thus isolated were provisionally designated shinshu-th1, -th2, -th 3, and five actinomycete strains, shinshu-ms-01, -02, -03, -04, -05, respectively. sequence analysis of their 16s rdna showed that th1 had 95--96% homology with three ...200516233821
calcium transport by frankia sp. strain ean1pec.when incubated at 25 degrees c, n2-grown cells of frankia strain ean1pec actively accumulated calcium, while nh4cl-grown cells did not accumulate calcium. when incubated at 0 degrees c, both n2-grown and nh4cl-grown cells did not actively accumulate calcium. inhibitors of respiration inhibited calcium accumulation by n2-grown cells at 25 degrees c. isolated vesicles also accumulated calcium in an energy- and temperature-dependent manner. two lines of evidence show that frankia strain ean1pec has ...19989625783
pcr-restriction fragment length polymorphism identification and host range of single-spore isolates of the flexible frankia sp. strain ufi 132715.twelve single-spore isolates of the flexible elaeagnus-frankia strain ufi 132715 fulfilled the third and the fourth of koch's postulates on both alnus and elaeagnus axenic plants. seminested nifd-nifk pcr-restriction fragment length polymorphisms provided evidence for the genetic uniformity of the single-spore frankiae with the mother strain and its plant reisolates and allowed their molecular identification directly inside alnus and elaeagnus nodules. the clonal nature of these single-spore-pur ...19968702296
plasmids in frankia sp.a method to achieve cell lysis and isolate frankia sp. plasmid dna was developed. a screening of frankia sp. strains belonging to different host compatibility groups (alnus sp., elaeagnus sp., ceanothus sp.) showed that, of 39 strains tested, 4 (strains cp11, argn22d, ari3, and eun1f) possessed plasmids ranging in size from 7.1 to 32.2 kilobase pairs as estimated from agarose gel electrophoresis and electron microscopy. a total of 11 plasmids were detected.19836863219
consequences of sporangial development for nodule function in root nodules of comptonia peregrina and myrica gale.frankia sp., the actinomycetous endophyte in nitrogen-fixing actinorhizal nodules, may differentiate two forms from its hyphae: vesicles and sporangia. in root nodules of comptonia peregrina (l.) coult. and myrica gale l., sporangia may be either absent or present. nitrogenase activity and symbiotic efficiency were contrasted in spore(+) and spore(-) nodules of these two host genera. seedlings of c. peregrina nodulated with the spore(+) inoculum showed only 60% of the nitrogenase activity and 50 ...198416663881
oxygen protection of nitrogenase in frankia sp. hfpari3.o2 protection of nitrogenase in a cultured frankia isolate from alnus rubra (hfpari3) was studied in vivo. evidence for a passive gas diffusion barrier in the vesicles was obtained by kinetic analysis of in vivo o2 uptake and acetylene reduction rates in response to substrate concentration. o2 of nh4+-grown cells showed an apparent kmo2 of approximately 1 microm o2. in n2-fixing cultures a second km o2 of about 215 microm o2 was observed. thus, respiration remained unsaturated by o2 at air-satur ...19846595968
initiation and ontogeny of vesicles in cultured frankia sp. strain hfpari3.removal of combined nitrogen from the medium of frankia sp. strain hfpari3 induced the formation of specialized structures, called vesicles, which are the proposed site of nitrogen fixation. after 5 to 6 h of culture on n-free medium, newly formed vesicles, termed provesicles, arose from the tips of some hyphae. these structures were spherical, phase dark, ca. 1.5 to 2.0 micron in diameter, and were not associated with acetylene reduction (nitrogenase) activity. provesicles reached their greates ...19846594327
effect of o2 on vesicle formation, acetylene reduction, and o2-uptake kinetics in frankia sp. hfpcci3 isolated from casuarina cunninghamiana.the effect of the partial pressure of oxygen (po2) on the formation of vesicles, which are thought to be the site of n2 fixation in frankia, was studied in hfpcci3, an effective isolate from casuarina cunninghamiana. unlike other actinorhizal root nodules, vesicles are not produced by the endophyte in casuarina nodules. however, in culture under aerobic conditions, large, phase-bright vesicles are formed in hfpcci3 within 20 h following removal of nh+4 from the culture medium and reach peak numb ...19853866636
isolation and nitrogenase activity of vesicles from frankia sp. strain ean1pec.vesicles, specialized cell structures thought to be the site of nitrogen fixation in the actinorhizal bacteria, were isolated from frankia sp. strain ean1pec by using french pressure disruption of mycelia followed by differential and isopycnic gradient centrifugation. the isolated vesicles reduced acetylene when incubated anaerobically with mg2+ ions, atp, and dithionite. no nitrogenase activity was detected in the disrupted mycelial fractions. vesicles permeabilized by freeze-thaw or detergents ...19873478333
enzyme-linked immunosorbent assay (elisa) as a means of taxonomic analysis of streptomyces and related organisms.fourteen streptomyces strains from various numerical taxonomic classes and representatives of three other genera of actinomycetes were studied using an indirect enzyme-linked immunosorbent assay (ind-elisa) to determine their serological relationships. the ind-elisa results agreed with those from previous numerical taxonomic analyses and ouchterlony double-diffusion studies. the ind-elisa method is quicker, more quantitative and less subjective than ouchterlony assays and thus should be useful i ...19863098902
comparative secretome analysis suggests low plant cell wall degrading capacity in frankia symbionts.frankia sp. strains, the nitrogen-fixing facultative endosymbionts of actinorhizal plants, have long been proposed to secrete hydrolytic enzymes such as cellulases, pectinases, and proteases that may contribute to plant root penetration and formation of symbiotic root nodules. these or other secreted proteins might logically be involved in the as yet unknown molecular interactions between frankia and their host plants. we compared the genome-based secretomes of three frankia strains representing ...200818226217
molecular cloning, sequencing, and expression of the glutamine synthetase ii (glnii) gene from the actinomycete root nodule symbiont frankia sp. strain cpi1.in common with other plant symbionts, frankia spp., the actinomycete n2-fixing symbionts of certain nonleguminous woody plants, synthesize two glutamine synthetases, gsi and gsii. dna encoding the bradyrhizobium japonicum gene for gsii (glnii) hybridized to dna from three frankia strains. b. japonicum glnii was used as a probe to clone the glnii gene from a size-selected kpni library of frankia strain cpi1 dna. the region corresponding to the frankia sp. strain cpi1 glnii gene was sequenced, and ...19901975584
high-molecular-mass multicatalytic proteinase complexes produced by the nitrogen-fixing actinomycete frankia strain br.a major-high-molecular mass proteinase and seven latent minor proteinases were found in cell extracts and in concentrates of culture medium from frankia sp. strain br after nondenaturing electrophoresis in mixed gelatin-polyacrylamide gels. all of these complexes showed multicatalytic properties. their molecular masses and their sedimentation coefficients varied from 1,300 kda (28s) to 270 kda (12s). the electroeluted 1,300-kda proteinase complex dissociated into 11 low-molecular-mass proteinase ...19921537794
isolation and characterization of frankia sp. strain fac1 genes involved in nitrogen fixation.genomic dna was isolated from frankia sp. strain fac1, an alnus root nodule endophyte, and used to construct a genomic library in the cosmid vector phc79. the genomic library was screened by in situ colony hybridization to identify clones of frankia nitrogenase (nif) genes based on dna sequence homology to structural nitrogenase genes from klebsiella pneumoniae. several frankia nif clones were isolated, and hybridization with individual structural nitrogenase gene fragments (nifh, nifd, and nifk ...198716347453
diminished exoproteome of frankia spp. in culture and symbiosis.frankia species are the most geographically widespread gram-positive plant symbionts, carrying out n(2) fixation in root nodules of trees and woody shrubs called actinorhizal plants. taking advantage of the sequencing of three frankia genomes, proteomics techniques were used to investigate the population of extracellular proteins (the exoproteome) from frankia, some of which potentially mediate host-microbe interactions. initial two-dimensional sodium dodecyl sulfate-polyacrylamide gel electroph ...200919749056
insertion sequence content reflects genome plasticity in strains of the root nodule actinobacterium frankia.genome analysis of three frankia sp. strains has revealed a high number of transposable elements in two of the strains. twelve out of the 20 major families of bacterial insertion sequence (is) elements are represented in the 148 annotated transposases of frankia strain hfpcci3 (cci3) comprising 3% of its total coding sequences (cds). ean1pec (ean) has 183 transposase orfs from 13 is families comprising 2.2% of its cds. strain acn14a (acn) differs significantly from the other strains with only 33 ...200919821988
high-throughput screening of microbial adaptation to environmental stress.we developed a microwell plate, high-throughput, screening method aimed at quantitating the tolerance of a panel of gram-positive and gram-negative bacteria to metals (frankia sp., escherichia coli, cupriavidus metallidurans, rhizobium leguminosarum, and streptomyces scabies). microbial viability was quantified using mts; a tetrazolium salt converted to a water-soluble formazan through microbial reduction. in this paper, we present the stepwise development of the method, highlighting the main el ...201121315114
evidence that some frankia sp. strains are able to cross boundaries between alnus and elaeagnus host specificity groups.phenotypic and genotypic methods were used to prove the existence of frankia strains isolated from an elaeagnus sp. that are able to cross the inoculation barriers and infect alnus spp. also. repeated cycles of inoculation, nodulation, and reisolation were performed under axenic conditions. frankia wild-type strain ufi 13270257 and three of its coisolates did exhibit complete infectivity and effectiveness on elaeagnus spp. and hippophaë rhamnoides and variable infectivity on alnus spp. microscop ...19921352442
modification of the protein expression pattern induced in the nitrogen-fixing actinomycete frankia sp. strain acn14a-tsr by root exudates of its symbiotic host alnus glutinosa and cloning of the sodf gene.two-dimensional (2-d) polyacrylamide gel electrophoresis was used to detect proteins induced in frankia sp. strain acn14a-tsr by root exudates of its symbiotic host, alnus glutinosa. the 5 most prominent proteins were purified from 2-d gels and characterized by n-terminal sequencing. all of these proteins had a high percentage of similarity with known stress proteins. one protein match was the fe superoxide dismutase (fe-sod), another was a tellurite resistance protein (ter), the third was a bac ...200111467730
differences in fatty acid composition between vegetative cells and n(2)-fixing vesicles of frankia sp. strain cpi1.when growing on n(2), actinomycetes from the genus frankia form multicellular structures that contain nitrogenase. the structures are referred to as vesicles and are indistinguishable from vesicles formed when frankia sp. are in root-nodule symbioses. vesicles isolated from n(2)-grown cells of frankia sp. strain cpi1 had a significantly higher amount and different composition of fatty acids than did vegetative cells recovered from nh(4) (+)-containing medium. lipids from vesicles, whole cells gr ...198916594036
transcriptomes of frankia sp. strain cci3 in growth transitions.frankia sp. strains are actinobacteria that form n2-fixing root nodules on angiosperms. several reference genome sequences are available enabling transcriptome studies in frankia sp. genomes from frankia sp. strains differ markedly in size, a consequence proposed to be associated with a high number of indigenous transposases, more than 200 of which are found in frankia sp. strain cci3 used in this study. because frankia exhibits a high degree of cell heterogeneity as a consequence of its mycelia ...201121867524
dinitrogen fixation by cultures of frankia sp cpil demonstrated by n(2) incorporation.the filamentous bacterium frankia of the actinomycetales, isolated from the nitrogen-fixing root nodules of certain woody plants, has shown nitrogenase activity in culture, using the acetylene reduction method. in the present work, nitrogenase activity in pure cultures of frankia sp. cpil is confirmed using mass spectrometric measurements of (15)n(2) incorporation. after addition of carrier nh(4) (+) to digested cultures, those exposed to (15)n(2) (25 atom%) had a (15)n content of 3.16 atom% com ...198116662039
Casuarina Root Exudates Alter the Physiology, Surface Properties, and Plant Infectivity of Frankia sp. Strain CcI3.The actinomycete genus Frankia forms nitrogen-fixing symbioses with 8 different families of actinorhizal plants, representing more than 200 different species. Very little is known about the initial molecular interactions between Frankia and host plants in the rhizosphere. Root exudates are important in Rhizobium-legume symbiosis, especially for initiating Nod factor synthesis. We measured differences in Frankia physiology after exposure to host aqueous root exudates to assess their effects on ac ...201222101047
comparison of 16s ribosomal rna genes in clavibacter michiganensis subspecies with other coryneform bacteria.nearly complete sequences (97-99%) of the 16s rrna genes were determined for type strains of clavibacter michiganensis subsp. michiganensis, clavibacter michiganensis subsp. insidiosus, clavibacter michiganensis subsp. sepedonicus, and clavibacter michiganensis subsp. nebraskensis. the four subspecies had less than 1% dissimilarity in their 16s rrna genes. comparative studies indicated that the c. michiganensis subsp. shared relatively high homology with the 16s rrna gene of clavibacter xyli. fu ...19958590406
morphological and molecular characterization of frankia sp. isolates from nodules of alnus nepalensis don.nodules collected from alnus nepalensis growing in mixed forest stands at three different sites around shillong, were crushed in various culture media to obtain isolates of frankia. the isolates were found to have typical frankia morphology as revealed by the scanning electron microscope. seedlings inoculated with isolates or crushed nodules formed nitrogen fixing nodules. frankia specific dna probes amplified the dna of the tested isolate anpus4. partial nucleotide sequence of the 16s rrna gene ...19947511370
characterization of an ineffective actinorhizal microsymbiont, frankia sp. eui1 (actinomycetales).the actinomycete, frankia sp. eui1, isolated from root nodules of elaeagnus umbellata is an infective endophyte but which lacks the ability to form an effective nitrogen-fixing symbiosis with its host. this ineffective organism can be distinguished easily from other frankiae, in vitro, on the basis of size, morphology, and the elaboration of a diffusible pigment. cross-inoculation studies indicated that the host range of this symbiont is narrow and probably restricted to the elaeagnaceae. in all ...19807459722
characterization of an effective actinorhizal microsymbiont, frankia sp. avci1 (actinomycetales).the actinomycete, frankia sp. avci1, isolated from root nodules of alnus viridis ssp. crispa was grown in axenic culture and used to inoculate host seedlings. this bacterium has been shown to be an infective and effective nitrogen-fixing microsymbiont which can be distinguished from other frankiae, in vitro, on the basis of size, distinctive morphology, and growth characteristics. cross-inoculation studies indicated that the host range of this symbiont encompasses all of the members of the gener ...19807459721
cytokinin secretion by frankia sp. hfp ari3 in defined medium.frankia sp. hfp ari3 (host plant alnus rubra bong.) was grown in defined medium and the culture solution was analyzed for the presence of various cytokinins and related compounds. n(6)- (delta(2)-isopentenyl) adenosine was the only cytokinin detected by both high performance liquid chromatography and gas chromatography-mass spectrometry, at levels of approximately 1 ng/ml culture medium.198816666092
factors affecting vesicle formation and acetylene reduction (nitrogenase activity) in frankia sp. cpi1.vesicle formation and acetylene reduction (nitrogenase activity) were observed when washed hyphae from cultures of frankia sp. cpi1 were transferred to a nitrogen-free medium containing ethylenediaminetetraacetic acid and succinate. succinate could be replaced by malate or fumarate, but not other carbon sources. maximum acetylene reduction and vesicle numbers were observed at a ph of 6.0-6.5, at 25-30 degrees centigrade, and at atmos pheric po2 or somewhat less (5-20 kpa). addition of 1 mm nh ...19816794897
enzymes of glucose metabolism in frankia sp.enzymes of glucose metabolism were assayed in crude cell extracts of frankia strains hfpari3 and hfpcci2 as well as in isolated vesicle clusters from alnus rubra root nodules. activities of the embden-meyerhof-parnas pathway enzymes glucokinase, phosphofructokinase, and pyruvate kinase were found in frankia strain hfpari3 and glucokinase and pyruvate kinase were found in frankia strain hfpcci2 and in the vesicle clusters. an nadp+-linked glucose 6-phosphate dehydrogenase and an nad-linked 6-phos ...19853980434
isolation and nitrogen-fixing activity of frankia sp. strain cpi1 vesicles.under n2-fixing conditions in aerobic culture and in symbiosis, frankiae produce spherical, multicellular structures that have been called vesicles. the vesicles have been proposed as the site of nitrogen fixation. we isolated vesicles by using density centrifugation in a single-step sucrose gradient. vesicles migrated out of 50% (wt/vol) sucrose and banded at the 40 to 50% sucrose interface; they were intact, as assessed by transmission electron microscopy, and were free of hyphal contamination ...19862870056
enzymes of ammonia assimilation in hyphae and vesicles of frankia sp. strain cpi1.frankia spp. are filamentous actinomycetes that fix n2 in culture and in actinorhizal root nodules. in combined nitrogen-depleted aerobic environments, nitrogenase is restricted to thick-walled spherical structures, frankia vesicles, that are formed on short stalks along the vegetative hyphae. the activities of the nh4(+)-assimilating enzymes (glutamine synthetase [gs], glutamate synthase, glutamate dehydrogenase, and alanine dehydrogenase) were determined in cells grown on nh4+ and n2 and in ve ...19901968454
the actinorhizal root-nodule symbiont frankia sp. strain cpi1 has two glutamine synthetases.frankia sp. strain cpi1 has two glutamine synthetases. glutamine synthetase i (gsi) is present during growth on ammonium or n(2) and is similar to classical prokaryotic glutamine synthetases. gel-filtration chromatography gave a molecular weight estimate of about 680,000 for the gsi holoenzyme, and denaturing polyacrylamide gel electrophoresis yielded a subunit molecular weight of about 59,000, indicating that gsi is most likely a dodecamer. gsi is regulated by adenylylation, as shown by the pre ...198716578813
the cyanobacterium synechococcus sp. strain pcc 7942 contains a second alkaline phosphatase encoded by phov.a gene (phov) encoding an alkaline phosphatase from synechococcus sp. strain pcc 7942 was isolated by screening a plasmid gene bank for expression of alkaline phosphatase activity in escherichia coli jm103. two independent clones carrying the same alkaline-phosphatase-encoding gene were isolated. one of these clones (pkw1) was further analysed and the nucleotide sequence of a contiguous 3234 bp dna fragment was determined. two complete open reading frames (orf1 and phov) and an incomplete orf3 w ...19958574398
signature proteins that are distinctive characteristics of actinobacteria and their subgroups.the actinobacteria constitute one of the main phyla of bacteria. presently, no morphological and very few molecular characteristics are known which can distinguish species of this highly diverse group. in this work, we have analyzed the genomes of four actinobacteria (viz. mycobacterium leprae tn, leifsonia xyli subsp. xyli str. ctcb07, bifidobacterium longum ncc2705 and thermobifida fusca yx) to search for proteins that are unique to actinobacteria. our analyses have identified 233 actinobacter ...200616670965
genome characteristics of facultatively symbiotic frankia sp. strains reflect host range and host plant biogeography.soil bacteria that also form mutualistic symbioses in plants encounter two major levels of selection. one occurs during adaptation to and survival in soil, and the other occurs in concert with host plant speciation and adaptation. actinobacteria from the genus frankia are facultative symbionts that form n(2)-fixing root nodules on diverse and globally distributed angiosperms in the "actinorhizal" symbioses. three closely related clades of frankia sp. strains are recognized; members of each clade ...200717151343
a novel chimera: the "truncated hemoglobin-antibiotic monooxygenase" from streptomyces avermitilis.novel chimeric proteins made of a globin domain fused with a "cofactor free" monooxygenase domain have been identified within the streptomyces avermitilis and frankia sp. genomes by means of bioinformatics methods. structure based sequence alignments show that the globin domains of both proteins can be unambiguously assigned to the truncated hemoglobin family, in view of the striking similarity to the truncated hemoglobins from mycobacterium tuberculosis, thermobifida fusca and bacillus subtilis ...200717574781
the phylogeny of uptake hydrogenases in frankia.uptake hydrogenase is an enzyme that is beneficial for nitrogen fixation in bacteria. recent studies have shown that frankia sp. has two sets of uptake hydrogenase genes, organized in synton 1 and synton 2. in the present study, phylogenetic analysis of the structural subunits of hydrogenase syntons 1 and 2 showed a distinct clustering pattern between the proteins of frankia strains that were isolated from different host plants and non-frankia organisms. the structural subunits of hydrogenase sy ...200919440980
isolation and structure of the lipid envelopes from the nitrogen-fixing vesicles of frankia sp. strain cpi1.frankia vesicles are differentiated during nitrogen starvation; they contain nitrogenase whether produced by free-living frankiae or by frankiae in actinorhizal root nodules. vesicles are surrounded by envelopes of several monolayers of uncharacterized lipid. it has been suggested that the envelope limits diffusion of o2 into the vesicle cytoplasm, thereby preventing inactivation of nitrogenase. whole vesicles were prepared on sucrose gradients and sonicated, and vesicle envelopes were isolated ...19912002007
determination of the target nucleosides for members of two families of 16s rrna methyltransferases that confer resistance to partially overlapping groups of aminoglycoside antibiotics.the 16s ribosomal rna methyltransferase enzymes that modify nucleosides in the drug binding site to provide self-resistance in aminoglycoside-producing micro-organisms have been proposed to comprise two distinct groups of s-adenosyl-l-methionine (sam)-dependent rna enzymes, namely the kgm and kam families. here, the nucleoside methylation sites for three kgm family methyltransferases, sgm from micromonospora zionensis, grma from micromonospora echinospora and krm from frankia sp. ccl3, were expe ...200919589804
purification, characterization, molecular cloning, and expression of a new aminoacylase from streptomyces mobaraensis that can hydrolyze n-(middle/long)-chain-fatty-acyl-l-amino acids as well as n-short-chain-acyl-l-amino acids.we report here on the purification, characterization, molecular cloning, and expression of a new aminoacylase, initially isolated from the supernatant of streptomyces mobaraensis (sm-aa). purified wild-type sm-aa was found to be a monomeric protein with a molecular mass of 55 kda. the cloned gene of sm-aa contained an orf of 1,383 bp, encoding a polypeptide of 460 amino acids. a blast search revealed that sm-aa belongs to the peptidase m20 family, with identities to a hypothetical protein from s ...200919734688
[14c]methylammonium transport by frankia sp. strain cpi1.we describe an nh4+-specific transport system in the n2-fixing symbiotic actinomycete frankia sp. strain cpi1. [14c]methylammonium was used as an nh4+ analog. no specific transport process was detected when cells were grown on high concentrations of nh4+. a transport system with a high affinity for ch3nh3+ was synthesized after 3 to 4 h of nitrogen starvation. methylammonium transport was not significantly inhibited by a variety of amino acids, primary amines, and polyamines. ammonium completely ...19846501218
saprophytic growth of inoculated frankia sp. in soil microcosms.the potential of two frankia strains to grow saprophytically was studied in nonsterile soil microcosms with ground leaf litter of alnus glutinosa as the sole carbon and nitrogen sources. strains ag45/mut15 and ari3, which represent two taxonomic subgroups within the alnus host infection group were inoculated alone, or together to investigate potential competition. their growth was analyzed by in situ and dot-blot hybridization. a significant increase in cell numbers and filament length was obser ...200717916077
significant natural product biosynthetic potential of actinorhizal symbionts of the genus frankia, as revealed by comparative genomic and proteomic analyses.bacteria of the genus frankia are mycelium-forming actinomycetes that are found as nitrogen-fixing facultative symbionts of actinorhizal plants. although soil-dwelling actinomycetes are well-known producers of bioactive compounds, the genus frankia has largely gone uninvestigated for this potential. bioinformatic analysis of the genome sequences of frankia strains acn14a, cci3, and ean1pec revealed an unexpected number of secondary metabolic biosynthesis gene clusters. our analysis led to the id ...201121498757
growth and development of frankia spp. strain cci3 at the single-hypha level in liquid culture.filamentous actinobacteria from the genus frankia grow by hyphal tip extension and branching. the growth kinetics and branching pattern of frankia are not well studied, especially at the early stages of mycelial development. here, we compare the growth of frankia sp. strain cci3 in liquid cultures with and without proteose peptone #3 (pp3) using time-lapse photomicrography and image analysis. individual hyphae showed a pseudolinear increase in length at early stages of development, whereas at th ...201121773799
organization of nif gene cluster in frankia sp. euik1 strain, a symbiont of elaeagnus umbellata.the nucleotide sequence of a 20.5-kb genomic region harboring nif genes was determined and analyzed. the fragment was obtained from frankia sp. euik1 strain, an indigenous symbiont of elaeagnus umbellata. a total of 20 orfs including 12 nif genes were identified and subjected to comparative analysis with the genome sequences of 3 frankia strains representing diverse host plant specificities. the nucleotide and deduced amino acid sequences showed highest levels of identity with orthologous genes ...201121769644
the biology of frankia sp. strains in the post-genome era.progress in understanding symbiotic determinants involved in the n(2)-fixing actinorhizal plant symbioses has been slow but steady. problems persist with studying the bacterial contributions to the symbiosis using traditional microbiological techniques. however, recent years have seen the emergence of several genomes from frankia sp. strains and the development of techniques for manipulating plant gene expression. approaches to understanding the bacterial side of the symbiosis have employed a ra ...201121848398
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