identification of soil bacteria expressing a symbiotic plasmid from rhizobium leguminosarum bv. trofolii.a hundred strains of non-nodulating, gram-negative, rod-shaped bacteria were isolated from clover-ryegrass pastures on three different soil types and from a sandy loam under lupins. when crossed with escherichia coli pn200 containing the cointegrate plasmid ppn1, 11 transconjugants gained the ability to form nodules on the roots of white clover (trifolium repens cv. grasslands huia). a noda probe indicated that they had gained nodulation genes. the identities of these 11 strains and 4 others der ...19979090106
proposal for rejection of agrobacterium tumefaciens and revised descriptions for the genus agrobacterium and for agrobacterium radiobacter and agrobacterium rhizogenes.the 16s rrna sequences of seven representative agrobacterium strains, eight representative rhizobium strains, and the type strains of azorhizobium caulinodans and bradyrhizobium japonicum were determined. these strains included the type strains of agrobacterium tumefaciens, agrobacterium rhizogenes, agrobacterium radiobacter, agrobacterium vitis, agrobacterium rubi, rhizobium fredii, rhizobium galegae, rhizobium huakuii, rhizobium leguminosarum, rhizobium loti, rhizobium meliloti, and rhizobium ...19938240952
novel and complex chromosomal arrangement of rhizobium loti nodulation genes.a mutational and structural analysis of rhizobium loti nodulation genes in strains nzp2037 and nzp2213 was carried out. unlike the case with other rhizobium strains examined to date, nodb was found on an operon separate from nodacij. sequence analysis of the nodacij and nodb operon regions confirm that r. loti common nod genes have a gene organization different from that of other rhizobium spp. at least 4 copies of nodd-like sequences were identified in r. loti. the complete nucleotide sequence ...19968850088
cloning of nod gene regions from mesquite rhizobia and bradyrhizobia and nucleotide sequence of the nodd gene from mesquite rhizobia.nitrogen-fixing symbiosis between bacteria and the tree legume mesquite (prosopis glandulosa) is important for the maintenance of many desert ecosystems. genes essential for nodulation and for extending the host range to mesquite were isolated from cosmid libraries of rhizobium (mesquite) sp. strain hw17b and bradyrhizobium (mesquite) sp. strain hw10h and were shown to be closely linked. all of the cosmid clones of rhizobia that extended the host range of rhizobium (parasponia) sp. strain ngr234 ...19957574650
the requirement for exopolysaccharide precedes the requirement for flavolan-binding polysaccharide in nodulation of leucaena leucocephala by rhizobium lotirhizobium loti strain pn4115 (nzp2213 str-1) ineffectively nodulates leucaena leucocephala, i.e., strain pn4115 induces nodulation (nod+) and is able to invade these nodules (inv+), but fails to fix nitrogen (fix-). strain pn4115 does not synthesize a flavolan-binding polysaccharide (fbp), which is synthesized by the fully effective (nod+inv+fix+) r. loti strain pn184 (nzp2037 str-1). the fbp may offer protection from prodelphinidin-rich flavolans synthesized by lc. leucocephala. in this work, w ...19979042760
comparison of the chinese schema and the international antigenic typing system for serotyping pseudomonas aeruginosa.twelve strains of pseudomonas aeruginosa representing 12 serogroups in the serogrouping schema used in the people's republic of china were compared with serogroups in the international antigenic typing system (iats). the first eight groups originated in the people's republic of china, and group ii appears to have a new major antigen that is not found in the iats. groups i, iii, iv, v, vi, vii, and viii correspond to groups 11, 6, 9, 4, 8, 3, and 1, respectively, of the iats. groups ix, x, xi, an ...19873108310
chemical characterization of two lipopolysaccharide species isolated from rhizobium loti nzp2213.phenol-water extraction of rhizobium loti nzp2213 cells allowed a simultaneous isolation of two structurally different lipopolysaccharides from the aqueous (lps-w) and phenol (lps-p) phase that differed in their sodium deoxycholate-page pattern and composition. lps-w showed a profile indicating an r-type lps; lps-p had a cluster of poorly resolved bands in the high-molecular-weight region. lps-p contained large amounts of 6-deoxy-l-talose (6dtal), and a small amount of 2-o-methyl-6-deoxy-talose ...19957794102
nucleotide sequence of rhizobium loti nodi. 19902251131
nucleotide sequence of rhizobium loti nodc. 19902251130
nonlegume hemoglobin genes retain organ-specific expression in heterologous transgenic plants.hemoglobin genes from the nitrogen-fixing nonlegume parasponia andersonii and the related non-nitrogen-fixing nonlegume trema tomentosa have been isolated [landsmann et al. (1986). nature 324, 166-168; bogusz et al. (1988). nature 331, 178-180]. the promoters of these genes have been linked to a beta-glucuronidase reporter gene and introduced into both the nonlegume nicotiana tabacum and the legume lotus corniculatus. both promoters directed root-specific expression in transgenic tobacco. when t ...19902136637
exopolysaccharide mutants of rhizobium loti are fully effective on a determinate nodulating host but are ineffective on an indeterminate nodulating tn5 mutagenesis of rhizobium loti pn184 (nzp2037 str-1) and selection for nonfluorescence of colonies on calcofluor agar, eight independently generated expolysaccharide (eps) mutants (three smooth and five rough) were isolated. the parent strain, pn184, was found to produce an acidic eps. this eps was produced. with reduced o acetylation, by the smooth eps mutants but not by the rough eps mutants. lipopolysaccharide was isolated from all mutants and was identical to that of pn184 as defined b ...19911987168
biosynthesis of cyclic beta-(1-3),beta-(1-6) glucan in bradyrhizobium spp.inner membranes of bradyrhizobium japonicum strain usda 110 produced in vitro soluble and insoluble beta-(1-3),beta-(1-6) glucans. the reaction proceeded through a 90 kda inner membrane intermediate protein; used udp-glucose as sugar donor and required mg2+. gel chromatography of soluble glucans resolved a cyclic beta-(1-3) glucan with a degree of polymerization of eleven from a family of beta-(1-3),beta-(1-6) glucans with variable degree of polymerization higher than eleven. bradyrhizobium stra ...19938427547
nodulating strains of rhizobium loti arise through chromosomal symbiotic gene transfer in the environment.rhizobia were isolated from nodules off a stand of lotus corniculatus established with a single inoculant strain, icmp3153, 7 years earlier in an area devoid of naturalized rhizobium loti. the isolates showed diversity in growth rate, spe i fingerprint of genomic dna, and hybridization pattern to genomic dna probes. the 19% of isolates that grew at the same rate as strain icmp3153 were the only isolates that had the same fingerprint as strain icmp3153. sequencing of part of the 16s rrna gene of ...19957568057
isolation and characterization of a rhizobium loti gene required for effective nodulation of lotus pedunculatus.a rhizobium loti gene required for effective invasion of the host lotus pedunculatus has been identified by transposon tn5 mutagenesis. cosmids that complemented a previously isolated mutation (239) at this invasion (inv) locus were identified by in planta complementation and used to construct a physical map of the gene region. the insertion site of tn5 in pn239 was mapped to a 7.5-kb ecori fragment, which complemented the mutation when subcloned into plafr1. further tn5 mutagenesis of the 7.5-k ...19892520823
leukotriene b4 omega-oxidation by human polymorphonuclear leukocytes is inhibited by pyocyanin, a phenazine derivative produced by pseudomonas aeruginosa.human polymorphonuclear leukocytes (pmnl) metabolize the potent chemotaxin leukotriene b4 (ltb4) by omega-oxidation to 20-hydroxyl-ltb4 and 20-carboxy-ltb4. the ability of unstimulated human pmnl to metabolize exogenous ltb4 was found to be inhibited by pyocyanin, a phenazine derivative produced by pseudomonas aeruginosa, in a dose-dependent manner. 1-hydroxyphenazine (1-ohp), a metabolite of pyocyanin, was not inhibitory under identical conditions. the initial enzymic step in the conversion of ...19921316878
the requirement for exopolysaccharide precedes the requirement for flavolan-binding polysaccharide in nodulation of leucaena leucocephala by rhizobium loti.rhizobium loti strain pn4115 (nzp2213 str-1) ineffectively nodulates leucaena leucocephala, i.e., strain pn4115 induces nodulation (nod+) and is able to invade these nodules (inv+), but fails to fix nitrogen (fix-). strain pn4115 does not synthesize a flavolan-binding polysaccharide (fbp), which is synthesized by the fully effective (nod+inv+fix+) r. loti strain pn184 (nzp2037 str-1). the fbp may offer protection from prodelphinidin-rich flavolans synthesized by lc. leucocephala. in this work, w ...19979133327
three phylogenetic groups of noda and nifh genes in sinorhizobium and mesorhizobium isolates from leguminous trees growing in africa and latin america.the diversity and phylogeny of noda and nifh genes were studied by using 52 rhizobial isolates from acacia senegal, prosopis chilensis, and related leguminous trees growing in africa and latin america. all of the strains had similar host ranges and belonged to the genera sinorhizobium and mesorhizobium, as previously determined by 16s rrna gene sequence analysis. the restriction patterns and a sequence analysis of the noda and nifh genes divided the strains into the following three distinct grou ...19989464375
bacterial nodulation protein nodz is a chitin oligosaccharide fucosyltransferase which can also recognize related substrates of animal origin.the nodz gene, which is present in various soil bacteria such as bradyrhizobium japonicum, azorhizobium caulinodans, and rhizobium loti, is involved in the addition of a fucosyl residue to the reducing n-acetylglucosamine residue of lipochitin oligosaccharide (lco) signal molecules. using an escherichia coli strain that produces large quantities of the nodz protein of b. japonicum, we have purified the nodz protein to homogeneity. the purified nodz protein appears to be active in an in vitro tra ...19979113990
genetic manipulation of condensed tannins in higher plants. ii. analysis of birdsfoot trefoil plants harboring antisense dihydroflavonol reductase constructswe have produced and analyzed transgenic birdsfoot trefoil (lotus corniculatus l.) plants harboring antisense dihydroflavonol reductase (as-dfr) sequences. in initial experiments the effect of introducing three different antisense antirrhinum majus l. dfr constructs into a single recipient genotype (s50) was assessed. there were no obvious effects on plant biomass, but levels of condensed tannins showed a statistical reduction in leaf, stem, and root tissues of some of the antisense lines. trans ...19989501146
xanthomonas campestris pv. campestris gum mutants: effects on xanthan biosynthesis and plant virulence.xanthan is an industrially important exopolysaccharide produced by the phytopathogenic, gram-negative bacterium xanthomonas campestris pv. campestris. it is composed of polymerized pentasaccharide repeating units which are assembled by the sequential addition of glucose-1-phosphate, glucose, mannose, glucuronic acid, and mannose on a polyprenol phosphate carrier (l. ielpi, r. o. couso, and m. a. dankert, j. bacteriol. 175:2490-2500, 1993). a cluster of 12 genes in a region designated xpsi or gum ...19989537354
sinorhizobium teranga bv. acaciae ors1073 and rhizobium sp. strain ors1001, two distantly related acacia-nodulating strains, produce similar nod factors that are o carbamoylated, n methylated, and mainly sulfated.we have determined the structures of nod factors produced by strains representative of sinorhizobium teranga bv. acaciae and the so-called cluster u from the rhizobium loti branch, two genetically different symbionts of particular acacia species. compounds from both strains were found to be similar, i.e., mainly sulfated, o carbamoylated, and n methylated, indicating a close relationship between host specificity and nod factor structure, regardless of the taxonomy of the bacterial symbiont.19979139935
phylogenetic and genetic relationships of mesorhizobium tianshanense and related rhizobia.the genetic and phylogenetic relationships for strains of mesorhizobium tianshanense and its relatives were compared by an analysis of the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) of whole-cell proteins, dna-dna hybridization, and full 16s rrna gene sequencing. the strains of m. tianshanense formed a cluster which was distinct from those of other rhizobium species in the clustering analysis of sds-page. dna-dna relatedness between a-1bs (type strain of m. t ...19979226921
four unnamed species of nonsymbiotic rhizobia isolated from the rhizosphere of lotus corniculatus.previously, we found that genetically diverse rhizobia nodulating lotus corniculatus at a field site devoid of naturalized rhizobia had symbiotic dna regions identical to those of icmp3153, the inoculant strain used at the site (j. t. sullivan, h. n. patrick, w. l. lowther, d. b. scott, and c. w. ronson, proc. natl. acad. sci. usa 92:8985-8989, 1995). in this study, we characterized seven nonsymbiotic rhizobial isolates from the rhizosphere of l. corniculatus. these included two from plants at t ...19968702274
nickel availability and hupsl activation by heterologous regulators limit symbiotic expression of the rhizobium leguminosarum bv. viciae hydrogenase system in hup(-) rhizobia.a limited number of rhizobium and bradyrhizobium strains possess a hydrogen uptake (hup) system that recycles the hydrogen released from the nitrogen fixation process in legume nodules. to extend this ability to rhizobia that nodulate agronomically important crops, we investigated factors that affect the expression of a cosmid-borne hup system from rhizobium leguminosarum bv. viciae upm791 in r. leguminosarum bv. viciae, rhizobium etli, mesorhizobium loti, and sinorhizobium meliloti hup(-) strai ...200010698755
construction of a bidirectional promoter probe vector and its use in analysing nod gene expression in rhizobium loti.a broad-host-range bidirectional promoter reporter vector, pspv4, has been constructed to analyse the activity of cloned divergent regulatory regions. plasmid pspv4 contains a pair of divergent promoterless reporter genes (lacz and gusa) that are bisected by an extensive multiple cloning site. [corrected] the transcriptional fusion vector pspv4 has a distinct advantage over unidirectional promoter probe vectors in that it can determine the activity of a cloned bidirectional regulatory region sim ...19947959034
structural identification of the lipo-chitin oligosaccharide nodulation signals of rhizobium loti.rhizobium loti is a fast-growing rhizobium species that has been described as a microsymbiont of plants of the genus lotus. nodulation studies show that lotus plants are nodulated by r. loti, but not by most other rhizobium strains, indicating that r. loti produces specific lipo-chitin oligosaccharides (lcos) which are necessary for the nodulation of lotus plants. the lcos produced by five different rhizobium loti strains have been purified and were shown to be n-acetylglucosamine pentasaccharid ...19957783635
genomic heterogeneity of strains nodulating chickpeas (cicer arietinum l.) and description of rhizobium mediterraneum sp. nov.the genetic diversity of chickpea strains was studied by using 30 isolates obtained from nodules on chickpeas growing in uninoculated fields over a wide geographic range. the following taxonomic approaches were used: dna-dna relatedness analysis, restriction fragment length polymorphism analysis of the amplified 16s ribosomal dna (rdna) intergenic spacer (igs), and total 16s rrna sequence analysis. the division of chickpea-infective strains into two major phylogenetic groups (groups a and b) tha ...19957547282
molecular epidemiologic approaches to urinary tract infection gene discovery in uropathogenic escherichia coli.urinary tract infection (uti) is one of the most frequently acquired bacterial infections. the vast majority of utis are caused by a large, genetically heterogeneous group of escherichia coli. this genetic diversity has hampered identification of uti-related genes. a three-step experimental strategy was used to identify genes potentially involved in e. coli uti transmission or virulence: epidemiologic pairing of a uti-specific strain with a fecal control, differential cloning to isolated uti str ...200010722596
rhizobium ciceri sp. nov., consisting of strains that nodulate chickpeas (cicer arietinum l.).the taxonomic status of 16 collection strains of chickpea (cicer arietinum l.) rhizobia which were previously determined to belong to two groups (groups a and b) were compared with reference strains belonging to different genera and species of the family rhizobiaceae. we used the following taxonomic, phylogenetic, and phenotypic characteristics and approaches to study these organisms: dna homology, guanine-plus-cytosine content, restriction fragment length polymorphism of the amplified 16s-inter ...19947520739
cloning and identification of conjugative transfer origins in the rhizobium meliloti genome.a simple approach was used to identify rhizobium meliloti dna regions with the ability to convert a nontransmissible vector into a mobilizable plasmid, i.e., to contain origins of conjugative transfer (orit, mob). reca-defective r. meliloti merodiploid populations, where each individual contained a hybrid cosmid from an r. meliloti gr4 gene library, were used as donors en masse in conjugation with another r. meliloti recipient strain, selecting transconjugants for vector-encoded antibiotic resis ...19989721299
further studies of the role of cyclic beta-glucans in symbiosis. an ndvc mutant of bradyrhizobium japonicum synthesizes cyclodecakis-(1-->3)-beta-glucosyl.the cyclic beta-(1-->3),beta-(1-->6)-d-glucan synthesis locus of bradyrhizobium japonicum is composed of at least two genes, ndvb and ndvc. mutation in either gene affects glucan synthesis, as well as the ability of the bacterium to establish a successful symbiotic interaction with the legume host soybean (glycine max). b. japonicum strain ab-14 (ndvb::tn5) does not synthesize beta-glucans, and strain ab-1 (ndvc::tn5) synthesizes a cyclic beta-glucan lacking beta-(1-->6)-glycosidic bonds. we det ...199910069844
chitin oligosaccharide synthesis by rhizobia and zebrafish embryos starts by glycosyl transfer to o4 of the reducing-terminal residue.lipochitin oligosaccharides are organogenesis-inducing signal molecules produced by rhizobia to establish the formation of nitrogen-fixing root nodules in leguminous plants. chitin oligosaccharide biosynthesis by the mesorhizobium loti nodulation protein nodc was studied in vitro using membrane fractions of an escherichia coli strain expressing the cloned m. loti nodc gene. the results indicate that prenylpyrophosphate-linked intermediates are not involved in the chitin oligosaccharide synthesis ...199910194317
occurrence of choline and glycine betaine uptake and metabolism in the family rhizobiaceae and their roles in osmoprotectionthe role of glycine betaine and choline in osmoprotection of various rhizobium, sinorhizobium, mesorhizobium, agrobacterium, and bradyrhizobium reference strains which display a large variation in salt tolerance was investigated. when externally provided, both compounds enhanced the growth of rhizobium tropici, sinorhizobium meliloti, sinorhizobium fredii, rhizobium galegae, agrobacterium tumefaciens, mesorhizobium loti, and mesorhizobium huakuii, demonstrating their utilization as osmoprotectan ...199910224003
biosynthesis and degradation of nodule-specific rhizobium loti compounds in lotus nodules.two nodule-specific rhizobium loti compounds were identified in lotus tenuis and lotus pedunculatus nodules induced by strain nzp2037. one, a silver nitrate-positive cation called rhizolotine, has been characterized as the riboside of a novel alpha-hydroxyimino acid containing a 1,4,5,6-tetrahydropyrimidine ring (g. j. shaw, r. d. wilson, g. a. lane, l. d. kennedy, d. b. scott, and g. j. gainsford, j. chem. soc. chem. commun., p. 180-181, 1986), and the other, yellow-1, stains yellow with ninhyd ...19873025173
the mdoc gene of escherichia coli encodes a membrane protein that is required for succinylation of osmoregulated periplasmic glucans.osmoregulated periplasmic glucans (opgs) of escherichia coli are anionic oligosaccharides that accumulate in the periplasmic space in response to low osmolarity of the medium. their anionic character is provided by the substitution of the glucosidic backbone by phosphoglycerol originating from the membrane phospholipids and by succinyl residues from unknown origin. a phosphoglycerol-transferase-deficient mdob mutant was subjected to tn5 transposon mutagenesis, and putative mutant clones were scr ...199910368134
halomethane:bisulfide/halide ion methyltransferase, an unusual corrinoid enzyme of environmental significance isolated from an aerobic methylotroph using chloromethane as the sole carbon source.a novel dehalogenating/transhalogenating enzyme, halomethane:bisulfide/halide ion methyltransferase, has been isolated from the facultatively methylotrophic bacterium strain cc495, which uses chloromethane (ch(3)cl) as the sole carbon source. purification of the enzyme to homogeneity was achieved in high yield by anion-exchange chromatography and gel filtration. the methyltransferase was composed of a 67-kda protein with a corrinoid-bound cobalt atom. the purified enzyme was inactive but was act ...199910508052
identification and disruption of lisrk, a genetic locus encoding a two-component signal transduction system involved in stress tolerance and virulence in listeria monocytogenes.lisrk encodes a two-component regulatory system in the food pathogen listeria monocytogenes lo28. following identification of the operon in an acid-tolerant tn917 mutant, a deletion in the histidine kinase component was shown to result in a growth phase variation in acid tolerance, an ability to grow in high ethanol concentrations, and a significant reduction in virulence.199910542190
development of pcr assays for species- and type-specific identification of pasteurella multocida isolates.genomic subtractive hybridization of closely related pasteurella multocida isolates has generated clones useful in distinguishing hemorrhagic septicemia-causing type b strains from other p. multocida serotypes. oligonucleotide primers designed during the sequencing of these clones have proved valuable in the development of pcr assays for rapid species- and type-specific detection of p. multocida and of type b:2 in particular. this study demonstrated that the primer pair designed from the sequenc ...19989542944
transfer of an indigenous plasmid of rhizobium loti to other rhizobia and agrobacterium tumefaciens.rhizobium loti strains nzp2037 and nzp2213 were each found to contain a single large plasmid: prlo2037a (240 mdal) and prlo2213a (120 mdal), respectively. plasmid dna present in crude cell lysates of each strain and purified prlo2037a dna did not hybridize with pid1, a recombinant plasmid containing part of the nitrogen fixation (nif) region of r. meliloti, indicating that nif genes were not present on these plasmids. the transposon tn5 was inserted into prlo2037a and this plasmid was then trans ...19836313860
isolation and characterization of transposon tn5-induced symbiotic mutants of rhizobium loti.rhizobium loti nzp2037 and nzp2213, each cured of its single large indigenous plasmid, formed effective nodules on lotus spp., suggesting that the symbiotic genes are carried on the chromosome of these strains. by using psup1011 as a vector for introducing transposon tn5 into r. loti nzp2037, symbiotic mutants blocked in hair curling (hac), nodule initiation (noi), bacterial release (bar), and nitrogen fixation (nif/cof) on lotus pedunculatus were isolated. cosmids complementing the hac, noi, an ...19852984178
rhizobium-legume symbiosis and nitrogen fixation under severe conditions and in an arid climate.biological n(2) fixation represents the major source of n input in agricultural soils including those in arid regions. the major n(2)-fixing systems are the symbiotic systems, which can play a significant role in improving the fertility and productivity of low-n soils. the rhizobium-legume symbioses have received most attention and have been examined extensively. the behavior of some n(2)-fixing systems under severe environmental conditions such as salt stress, drought stress, acidity, alkalinit ...199910585971
molecular basis of symbiotic promiscuity.eukaryotes often form symbioses with microorganisms. among these, associations between plants and nitrogen-fixing bacteria are responsible for the nitrogen input into various ecological niches. plants of many different families have evolved the capacity to develop root or stem nodules with diverse genera of soil bacteria. of these, symbioses between legumes and rhizobia (azorhizobium, bradyrhizobium, mesorhizobium, and rhizobium) are the most important from an agricultural perspective. nitrogen- ...200010704479
novel branched nod factor structure results from alpha-(1-->3) fucosyl transferase activity: the major lipo-chitin oligosaccharides from mesorhizobium loti strain nzp2213 bear an alpha-(1-->3) fucosyl substituent on a nonterminal backbone residue.mesorhizobium loti has been described as a microsymbiont of plants of the genus lotus. lipo-chitin oligosaccharides (lcos), or nod factors, produced by several representative m. loti strains all have similar structures. using fast-atom-bombardment tandem mass spectrometry and nmr spectroscopy, we have now examined the lcos from the type strain nzp2213 and observed a much greater variety of structures than has been described for the strains of m.loti studied previously. interestingly, we have ide ...19989636046
mobilization of plasmids and chromosomal dna mediated by the sxt element, a constin found in vibrio cholerae o139.the vibrio cholerae sxt element encodes resistance to multiple antibiotics and is a conjugative, self-transmissible, and chromosomally integrating element (a constin). excision and self-transfer of the sxt element require an element-encoded integrase. we now report that the sxt element can also mobilize the plasmids rsf1010 and clodf13 in trans as well as chromosomal dna in an hfr-like manner. sxt element-mediated mobilization of plasmids and chromosomal dna, unlike its self-transfer, is not dep ...200010715015
molecular diversity of rhizobia occurring on native shrubby legumes in southeastern australiathe structure of rhizobial communities nodulating native shrubby legumes in open eucalypt forest of southeastern australia was investigated by a molecular approach. twenty-one genomic species were characterized by small-subunit ribosomal dna pcr-restriction fragment length polymorphism and phylogenetic analyses, among 745 rhizobial strains isolated from nodules sampled on 32 different legume host species at 12 sites. among these rhizobial genomic species, 16 belonged to the bradyrhizobium subgro ...19989758831
evolution of rhizobia by acquisition of a 500-kb symbiosis island that integrates into a phe-trna gene.nodulation and nitrogen fixation genes of mesorhizobium loti are encoded on the chromosome of the bacterium. nevertheless, there is strong evidence that these genes can be transferred from an inoculant strain to nonsymbiotic mesorhizobia in the field environment. here we report that the chromosomal symbiotic element of m. loti strain icmp3153 is transmissible in laboratory matings to at least three genomic species of nonsymbiotic mesorhizobia. the element is 500 kb in size, integrates into a phe ...19989560243
cellular envelopes and tolerance to acid ph in mesorhizobium loti.changes in the cell envelopes in response to acidity were studied in two strains of mesorhizobium loti differing in their tolerance to ph. when the less acid-tolerant strain ll22 was grown at ph 5.5, membrane phosphatidylglycerol decreased and phosphatidylcholine increased, compared with cells grown at ph 7.0. on the other hand, when the more acid-tolerant strain ll56 was grown at ph 5.5, phosphatidylglycerol, phosphatidylethanolamine, and lysophospholipid decreased 25%, 39%, and 51% respectivel ...199910341073
genetic diversity and phylogeny of rhizobia that nodulate acacia spp. in morocco assessed by analysis of rrna genesforty rhizobia nodulating four acacia species (a. gummifera, a. raddiana, a. cyanophylla, and a. horrida) were isolated from different sites in morocco. these rhizobia were compared by analyzing both the 16s rrna gene (rdna) and the 16s-23s rrna spacer by pcr with restriction fragment length polymorphism (rflp) analysis. analysis of the length of 16s-23s spacer showed a considerable diversity within these microsymbionts, but rflp analysis of the amplified spacer revealed no additional heterogene ...19989835582
a new mesorhizobium loti hambi 1129 phage isolated from polish soil.phage a1 isolated from the rhizosphere of lotus corniculatus was studied. it had a very narrow host range, as it was active only against mesorhizobium loti hambi 1129. phage a1 was classified as belonging to c bradley's group bacteriophages. the latent period of a1 was 120-130 min and a burst size 13-17 particles per cell. the nature of the phage receptor was examined. lipopolysaccharide from the phage-sensitive strain inactivated phage a1 in contrast to lps from the phage-resistant bacteria. pu ...200010706666
a protein phosphatase 2c gene, ljnpp2c1, from lotus japonicus induced during root nodule development.symbiotic interactions between legumes and compatible strains of rhizobia result in root nodule formation. this new plant organ provides the unique physiological environment required for symbiotic nitrogen fixation by the bacterial endosymbiont and assimilation of this nitrogen by the plant partner. we have isolated two related genes (ljnpp2c1 and ljpp2c2) from the model legume lotus japonicus that encode protein phosphatase type 2c (pp2c). expression of the ljnpp2c1 gene was found to be enhance ...19999990094
catabolism of alpha-ketoglutarate by a suca mutant of bradyrhizobium japonicum: evidence for an alternative tricarboxylic acid cycle.a complete tricarboxylic acid (tca) cycle is generally considered necessary for energy production from the dicarboxylic acid substrates malate, succinate, and fumarate. however, a bradyrhizobium japonicum suca mutant that is missing alpha-ketoglutarate dehydrogenase is able to grow on malate as its sole source of carbon. this mutant also fixes nitrogen in symbiosis with soybean, where dicarboxylic acids are its principal carbon substrate. using a flow chamber system to make direct measurements o ...200010781553
symbiotic mutants deficient in nodule establishment identified after t-dna transformation of lotus japonicus.nitrogen-fixing root nodules develop on legumes as a result of an interaction between host plants and soil bacteria collectively referred to as rhizobia. the organogenic process resulting in nodule development is triggered by the bacterial microsymbiont, but genetically controlled by the host plant genome. using t-dna insertion as a tool to identify novel plant genes that regulate nodule ontogeny, we have identified two putatively tagged symbiotic loci, ljsym8 and ljsym13, in the diploid legume ...19989790598
int-b13, an unusual site-specific recombinase of the bacteriophage p4 integrase family, is responsible for chromosomal insertion of the 105-kilobase clc element of pseudomonas sp. strain b13.pseudomonas sp. strain b13 carries the clcrabde genes encoding chlorocatechol-degradative enzymes on the self-transmissible 105-kb clc element. the element integrates site and orientation specifically into the chromosomes of various bacterial recipients, with a glycine trna structural gene (glyv) as the integration site. we report here the localization and nucleotide sequence of the integrase gene and the activity of the integrase gene product in mediating site-specific integration. the integras ...19989791097
characterization of an atrazine-degrading pseudaminobacter sp. isolated from canadian and french agricultural soils.atrazine, a herbicide widely used in corn production, is a frequently detected groundwater contaminant. fourteen bacterial strains able to use this herbicide as a sole source of nitrogen were isolated from soils obtained from two farms in canada and two farms in france. these strains were indistinguishable from each other based on repetitive extragenic palindromic pcr genomic fingerprinting performed with primers eric1r, eric2, and boxa1r. based on 16s rrna sequence analysis of one representativ ...200010877767
the common nodulation genes of astragalus sinicus rhizobia are conserved despite chromosomal diversity.the nodulation genes of mesorhizobium sp. (astragalus sinicus) strain 7653r were cloned by functional complementation of sinorhizobium meliloti nod mutants. the common nod genes, nodd, noda, and nodbc, were identified by heterologous hybridization and sequence analysis. the noda gene was found to be separated from nodbc by approximately 22 kb and was divergently transcribed. the 2. 0-kb noddbc region was amplified by pcr from 24 rhizobial strains nodulating a. sinicus, which represented differen ...200010877796
alfalfa root nodule invasion efficiency is dependent on sinorhizobium meliloti polysaccharides.the soil bacterium sinorhizobium meliloti is capable of entering into a nitrogen-fixing symbiosis with medicago sativa (alfalfa). particular low-molecular-weight forms of certain polysaccharides produced by s. meliloti are crucial for establishing this symbiosis. alfalfa nodule invasion by s. meliloti can be mediated by any one of three symbiotically important polysaccharides: succinoglycan, eps ii, or k antigen (also referred to as kps). using green fluorescent protein-labeled s. meliloti cells ...200010894742
characterization of the d-xylulose 5-phosphate/d-fructose 6-phosphate phosphoketolase gene (xfp) from bifidobacterium lactis.a d-xylulose 5-phosphate/d-fructose 6-phosphate phosphoketolase (xfp) from the probiotic bifidobacterium lactis was purified to homogeneity. the specific activity of the purified enzyme with d-fructose 6-phosphate as a substrate is 4.28 units per mg of enzyme. k(m) values for d-xylulose 5-phosphate and d-fructose 6-phosphate are 45 and 10 mm, respectively. the native enzyme has a molecular mass of 550,000 da. the subunit size upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis (90,000 ...200111292814
noll of rhizobium sp. strain ngr234 is required for o-acetyltransferase activity.following (iso)flavonoid induction, nodulation genes of the symbiotic nitrogen-fixing bacterium rhizobium sp. strain ngr234 elaborate a large family of lipooligosaccharidic nod factors (nodngr factors). when secreted into the rhizosphere of compatible legumes, these signal molecules initiate root hair deformation and nodule development. the nonreducing glucosamine residue of nodngr factors are n acylated, n methylated, and mono- or biscarbamoylated, while position c-6 of the reducing extremity i ...19999922261
a phosphotransferase that generates phosphatidylinositol 4-phosphate (ptdins-4-p) from phosphatidylinositol and lipid a in rhizobium leguminosarum. a membrane-bound enzyme linking lipid a and ptdins-4-p biosynthesis.membranes of rhizobium leguminosarum contain a 3-deoxy-d-manno-octulosonic acid (kdo)-activated lipid a 4'-phosphatase required for generating the unusual phosphate-deficient lipid a found in this organism. the enzyme has been solubilized with triton x-100 and purified 80-fold. as shown by co-purification and thermal inactivation studies, the 4'-phosphatase catalyzes not only the hydrolysis of (kdo)2-[4'-32p]lipid iva but also the transfer the 4'-phosphate of kdo2-[4'-32p]lipid iva to the inosit ...199910196199
nodule-inducing activity of synthetic sinorhizobium meliloti nodulation factors and related lipo-chitooligosaccharides on alfalfa. importance of the acyl chain structure.sinorhizobium meliloti nodulation factors (nfs) elicit a number of symbiotic responses in alfalfa (medicago sativa) roots. using a semiquantitative nodulation assay, we have shown that chemically synthesized nfs trigger nodule formation in the same range of concentrations (down to 10(-10) m) as natural nfs. the absence of o-sulfate or o-acetate substitutions resulted in a decrease in morphogenic activity of more than 100-fold and approximately 10-fold, respectively. to address the question of th ...199910318686
identification and characterization of the brucella abortus phosphoglucomutase gene: role of lipopolysaccharide in virulence and intracellular multiplication.smooth lipopolysaccharide (lps) of brucella abortus has been reported to be an important virulence factor, although its precise role in pathogenesis is not yet clear. while the protective properties of lps against complement are well accepted, there is still some controversy about the capacity of rough mutants to replicate intracellularly. the b. abortus phosphoglucomutase gene (pgm) was cloned, sequenced, and disrupted. the gene has a high index of identity to agrobacterium tumefaciens pgm but ...200010992476
generation of new hydrogen-recycling rhizobiaceae strains by introduction of a novel hup minitransposon.hydrogen evolution by nitrogenase is a source of inefficiency for the nitrogen fixation process by the rhizobium-legume symbiosis. to develop a strategy to generate rhizobial strains with h(2)-recycling ability, we have constructed a tn5 derivative minitransposon (tnhb100) that contains the ca. 18-kb h(2) uptake (hup) gene cluster from rhizobium leguminosarum bv. viciae upm791. bacteroids from tnhb100-containing strains of r. leguminosarum bv. viciae pre, bradyrhizobium japonicum, r. etli, and m ...200011010872
lotus japonicus contains two distinct enod40 genes that are expressed in symbiotic, nonsymbiotic, and embryonic tissues.enod40, an early nodulin gene, has been postulated to play a significant role in legume root nodule ontogenesis. we have isolated two distinct enod40 genes from lotus japonicus. the transcribed regions of the two enod40 genes share 65% homology, while the two promoters showed no significant homology. both transcripts encode a putative dodecapeptide similar to that identified in other legumes forming determinate nodules. both enod40 genes are coordinately expressed following inoculation of roots ...200010975655
differentiation of o-acetyl and o-carbamoyl esters of n-acetyl-glucosamine by decomposition of their oxonium ions. application to the structure of the nonreducing terminal residue of nod factors.nod factors are substituted n-acyl chito-oligomers secreted by plant symbiotic bacteria of the rhizobium family. substitutions on the oligosaccharide core specify their recognition by host plants. a method using tandem mass spectrometry is proposed to locate the o-acetyl and o-carbamoyl substituents on the nonreducing terminal residue of the chito-oligomers. as model compounds, all the positional isomers of monoacetyl and monocarbamoyl esters of 1-o-methyl-n-acetyl-alpha-d-glucosamine were synth ...200010757166
analysis of cellular fatty acids and phenotypic relationships of agrobacterium, bradyrhizobium, mesorhizobium, rhizobium and sinorhizobium species using the sherlock microbial identification system.previous studies have demonstrated that cellular fatty acid analysis is a useful tool for identifying unknown strains of rhizobia and establishing taxonomic relationships between the species. in this study, the fatty acid profiles of over 600 strains belonging to the genera agrobacterium, bradyrhizobium, mesorhizobium, rhizobium and sinorhizobium were evaluated using the gaschromatography-based sherlock microbial identification system (mis). data collected with the mis showed that the three phyl ...200010758890
the lotus japonicus ljsym4 gene is required for the successful symbiotic infection of root epidermal cells.the role of the lotus japonicus ljsym4 gene during the symbiotic interaction with mesorhizobium loti and arbuscular mycorrhizal (am) fungi was analyzed with two mutant alleles conferring phenotypes of different strength. ljsym4-1 and ljsym4-2 mutants do not form nodules with m. loti. normal root hair curling and infection threads are not observed, while a nodc-dependent deformation of root hair tips indicates that nodulation factors are still perceived by ljsym4 mutants. fungal infection attempt ...200011043472
short root mutant of lotus japonicus with a dramatically altered symbiotic phenotype.legume plants carefully control the extent of nodulation in response to rhizobial infection. to examine the mechanism underlying this process we conducted a detailed analysis of the lotus japonicus hypernodulating mutants, har1-1, 2 and 3 that define a new locus, hypernodulation aberrant root formation (har1), involved in root and symbiotic development. mutations in the har1 locus alter root architecture by inhibiting root elongation, diminishing root diameter and stimulating lateral root initia ...200010929105
isolation of two different phenotypes of mycorrhizal mutants in the model legume plant lotus japonicus after ems-treatment.lotus japonicus has been proposed as a model plant for the molecular genetic study of plant-microbe interaction including mesorhizobium loti and arbuscular mycorrhizal (am) fungi. non-mycorrhizal mutants of lotus japonicus were screened from a collection of 12 mutants showing non-nodulating (nod-), ineffectively nodulating (fix-) and hypernodulating (nod++) phenotypes with monogenic recessive inheritance induced by ems (ethylmethane sulfonate) mutagenesis. three mycorrhizal mutant lines showing ...200010945342
genetic characterization of soybean rhizobia in paraguay.the soybean is an exotic plant introduced in paraguay in this century; commercial cropping expanded after the 1970s. inoculation is practiced in just 15 to 20% of the cropping areas, but root nodulation occurs in most sites where soybeans grow. little is known about rhizobial diversity in south america, and no study has been performed in paraguay until this time. therefore, in this study, the molecular characterization of 78 rhizobial isolates from soybean root nodules, collected under field con ...200011055970
functional analysis of chimeras derived from the sinorhizobium meliloti and mesorhizobium loti nodc genes identifies regions controlling chitin oligosaccharide chain length.the rhizobial nodulation gene nodc encodes an n-acetylglucosaminyltransferase that is responsible for the synthesis of chitin oligosaccharides. these oligosaccharides are precursors for the synthesis of the lipo-chitin oligosaccharides that induce cell division and differentiation during the development of nitrogen-fixing root nodules in leguminous plants. the nodc proteins of mesorhizobium loti and sinorizobium meliloti yield chitinpentaose and chitintetraose as their main products, respectivel ...200011016835
phylogenetic diversity of rhizobial strains nodulating robinia pseudoacacia l.lack of knowledge exists regarding the diversity of rhizobial strains nodulating black locust (robinia pseudoacacia l.), which is a neophytic tree species widely distributed in europe. seventeen rhizobial strains isolated from nodules of black locust at a german location were examined by phenotypic characterization and 16s rdna analysis. the isolates were classified in nine 16s rdna genotypes using a set of seven endonucleases. based on rflp analysis and sequencing, the strains were shown to bel ...200011065378
mesorhizobium loti increases root-specific expression of a calcium-binding protein homologue identified by promoter tagging in lotus japonicus.a promoter tagging program in the legume lotus japonicus was initiated to identify plant genes involved in the nitrogen-fixing symbiosis between legumes and rhizobia. seven transformed plant lines expressing the promoterless reporter gene uida (beta-glucuronidase; gus) specifically in roots and/or nodules were identified. four of these expressed gus in the roots only after inoculation with nodule-forming mesorhizobium loti. in one line (t90), gus activity was found in the root epidermis, includi ...200010830260
[sequencing the 16s rdna of representative strain of new rhizobial group and determining of its phylogenetic relationship].the full-length 16s rdna sequence of representative strain sh2672 were sequenced by the dideoxy-mediated chain-termination method. this sequence was compared with that of type strains of all known rhizobia and related bacteria. an unrooted phylogenetic tree was produced. in this tree, strain sh2672, mesorhizobium loti, m. huakuii, m. tianshanense, m. mediterraneum, and m. ciceri constituted a branch. within this branch, the similarity values of 16s rdna sequences between strain sh2672 and m. lot ...199711189370
lotus japonicus forms early senescent root nodules with rhizobium etli.mesorhizobium loti and rhizobium etli are microsymbionts of the lotus and phaseolus spp., respectively, and secrete essentially the same nod factors. lotus japonicus efficiently formed root nodules with r. etli ce3, irrespective of the presence or absence of a flavonoid-independent transcription activator nodd gene. on a nitrogen-free medium, however, the host plant inoculated with r. etli showed a severe nitrogen deficiency symptom. initially, the nodules formed with r. etli were pale pink and ...200111204780
a functional myo-inositol dehydrogenase gene is required for efficient nitrogen fixation and competitiveness of sinorhizobium fredii usda191 to nodulate soybean (glycine max [l.] merr.).inositol derivative compounds provide a nutrient source for soil bacteria that possess the ability to degrade such compounds. rhizobium strains that are capable of utilizing certain inositol derivatives are better colonizers of their host plants. we have cloned and determined the nucleotide sequence of the myo-inositol dehydrogenase gene (idha) of sinorhizobium fredii usda191, the first enzyme responsible for inositol catabolism. the deduced idha protein has a molecular mass of 34,648 da and sho ...200111274120
human alpha3-fucosyltransferases convert chitin oligosaccharides to products containing a glcnacbeta1-4(fucalpha1-3)glcnacbeta1-4r determinant at the nonreducing terminus.human alpha3-fucosyltransferases (fuc-ts) are known to convert n-acetyllactosamine to galbeta1-4(fucalpha1-3)glcnac (lewis x antigen); some of them transfer fucose also to galnacbeta1-4glcnac, generating galnacbeta1-4(fucalpha1-3)glcnac determinants. here, we report that recombinant forms of fuc-tv and fuc-tvi as well as fuc-ts of human milk converted chitin oligosaccharides of 2-4 glcnac units efficiently to products containing a glcnacbeta1-4(fucalpha1-3)glcnacbeta1-4r determinant at the nonre ...200111320059
complete genome structure of the nitrogen-fixing symbiotic bacterium mesorhizobium loti.the complete nucleotide sequence of the genome of a symbiotic bacterium mesorhizobium loti strain maff303099 was determined. the genome of m. loti consisted of a single chromosome (7,036,071 bp) and two plasmids, designated as pmla (351,911 bp) and pmlb (208, 315 bp). the chromosome comprises 6752 potential protein-coding genes, two sets of rrna genes and 50 trna genes representing 47 trna species. fifty-four percent of the potential protein genes showed sequence similarity to genes of known fun ...200011214968
numerical analysis of astragalus cicer microsymbionts.thirty-seven rhizobium strains, isolated from root nodules of astragalus cicer (l.) (cicer milkvetch) deriving from different geographic regions, were compared with the representative strains of the known rhizobial species and genera by numerical analysis of phenotypic characteristics. our results indicated that astragalus cicer rhizobia were related to the bacteria of mesorhizobium species and formed two major phena. one phenon, localized on mesorhizobium loti branch, contained strains from pol ...200010856381
rhizobial nodl o-acetyl transferase and nods n-methyl transferase functionally interfere in production of modified nod factors.the products of the rhizobial nodulation genes are involved in the biosynthesis of lipochitin oligosaccharides (lcos), which are host-specific signal molecules required for nodule formation. the presence of an o-acetyl group on c-6 of the nonreducing n-acetylglucosamine residue of lcos is due to the enzymatic activity of nodl. here we show that transfer of the nodl gene into four rhizobial species that all normally produce lcos that are not modified on c-6 of the nonreducing terminal residue res ...200111344149
the esat-6 gene cluster of mycobacterium tuberculosis and other high g+c gram-positive bacteria.the genome of mycobacterium tuberculosis h37rv has five copies of a cluster of genes known as the esat-6 loci. these clusters contain members of the cfp-10 (lhp) and esat-6 (esat-6) gene families (encoding secreted t-cell antigens that lack detectable secretion signals) as well as genes encoding secreted, cell-wall-associated subtilisin-like serine proteases, putative abc transporters, atp-binding proteins and other membrane-associated proteins. these membrane-associated and energy-providing pro ...200111597336
complete genome structure of the nitrogen-fixing symbiotic bacterium mesorhizobium loti (supplement). 200011214974
unusual methyl-branched alpha,beta-unsaturated acyl chain substitutions in the nod factors of an arctic rhizobium, mesorhizobium sp. strain n33 (oxytropis arctobia).mesorhizobium sp. strain n33 (oxytropis arctobia), a rhizobial strain isolated in arctic canada, is able to fix nitrogen at very low temperatures in association with a few arctic legume species belonging to the genera astragalus, onobrychis, and oxytropis. using mass spectrometry and nuclear magnetic resonance spectroscopy, we have determined the structure of n33 nod factors, which are major determinants of nodulation. they are pentameric lipochito-oligosaccharides 6-o sulfated at the reducing e ...200111371536
real-time measurements of the interaction between single cells of listeria monocytogenes and nisin on a solid surface.a method to obtain real-time measurements of the interactions between nisin and single cells of listeria monocytogenes on a solid surface was developed. this method was based on fluorescence ratio-imaging microscopy and measurements of changes in the intracellular ph (ph(i)) of carboxyfluorescein succinimidyl ester-stained cells during exposure to nisin. immobilized cells were placed in a chamber mounted on a microscope and attached to a high-precision peristaltic pump which allowed rapid change ...200010919824
isolation and characterization of diverse halobenzoate-degrading denitrifying bacteria from soils and sediments.denitrifying bacteria capable of degrading halobenzoates were isolated from various geographical and ecological sites. the strains were isolated after initial enrichment on one of the monofluoro-, monochloro-, or monobromo-benzoate isomers with nitrate as an electron acceptor, yielding a total of 33 strains isolated from the different halobenzoate-utilizing enrichment cultures. each isolate could grow on the selected halobenzoate with nitrate as the terminal electron acceptor. the isolates obtai ...200010919805
specific detection of bradyrhizobium and rhizobium strains colonizing rice (oryza sativa) roots by 16s-23s ribosomal dna intergenic spacer-targeted addition to forming symbiotic nodules on legumes, rhizobial strains are members of soil or rhizosphere communities or occur as endophytes, e.g., in rice. two rhizobial strains which have been isolated from root nodules of the aquatic legumes aeschynomene fluminensis (irbg271) and sesbania aculeata (irbg74) were previously found to promote rice growth. in addition to analyzing their phylogenetic positions, we assessed the suitability of the 16s-23s ribosomal dna (rdna) intergenic spacer (igs) ...200111472944
enrichment of high-affinity co oxidizers in maine forest soil.carboxydotrophic activity in forest soils was enriched by incubation in a flowthrough system with elevated concentrations of headspace co (40 to 400 ppm). co uptake increased substantially over time, while the apparent k(m) ((app)k(m)) for uptake remained similar to that of unenriched soils (<10 to 20 ppm). carboxydotrophic activity was transferred to and further enriched in sterile sand and forest soil. the (app)k(m)s for secondary and tertiary enrichments remained similar to values for unenric ...200111472946
a lotus japonicus nodulation system based on heterologous expression of the fucosyl transferase nodz and the acetyl transferase noil in rhizobium leguminosarum.heterologous expression of nodz and noll proteins in rhizobium leguminosarum bv. viciae led to the production of acetyl fucosylated lipo-chitin oligosaccharides (lcos), indicating that the noll protein obtained from mesorhizobium loti functions as an acetyl transferase. we show that the noll-dependent acetylation is specific for the fucosyl penta-n-acetylglucosamine species. in addition, the noll protein caused elevated production of lcos. efficient nodulation of lotus japonicus by the nodz/noll ...200010755312
small-subunit rrna genotyping of rhizobia nodulating australian acacia spp.the structure of rhizobial communities nodulating acacia in southeastern australia from south queensland to tasmania was investigated by a molecular approach. a total of 118 isolates from nodule samples from 13 different acacia species collected at 44 sites were characterized by small-subunit (ssu) ribosomal dna (rdna) pcr-restriction fragment length polymorphism analysis. nine rhizobial genomospecies were identified, and these taxa corresponded to previously described genomospecies (b. lafay an ...200111133471
potential symbiosis-specific genes uncovered by sequencing a 410-kilobase dna region of the bradyrhizobium japonicum chromosome.the physical and genetic map of the bradyrhizobium japonicum chromosome revealed that nitrogen fixation and nodulation genes are clustered. because of the complex interactions between the bacterium and the plant, we expected this chromosomal sector to contain additional genes that are involved in the maintenance of an efficient symbiosis. therefore, we determined the nucleotide sequence of a 410-kb region. the overall g+c nucleotide content was 59.1%. using a minimum gene length of 150 nucleotid ...200111157954
the complete sequence of the 1,683-kb psymb megaplasmid from the n2-fixing endosymbiont sinorhizobium meliloti.analysis of the 1,683,333-nt sequence of the psymb megaplasmid from the symbiotic n(2)-fixing bacterium sinorhizobium meliloti revealed that the replicon has a high gene density with a total of 1,570 protein-coding regions, with few insertion elements and regions duplicated elsewhere in the genome. the only copies of an essential arg-trna gene and the mincde genes are located on psymb. almost 20% of the psymb sequence carries genes encoding solute uptake systems, most of which were of the atp-bi ...200111481431
nucleotide sequence and predicted functions of the entire sinorhizobium meliloti psyma megaplasmid.the symbiotic nitrogen-fixing soil bacterium sinorhizobium meliloti contains three replicons: psyma, psymb, and the chromosome. we report here the complete 1,354,226-nt sequence of psyma. in addition to a large fraction of the genes known to be specifically involved in symbiosis, psyma contains genes likely to be involved in nitrogen and carbon metabolism, transport, stress, and resistance responses, and other functions that give s. meliloti an advantage in its specialized niche.200111481432
enzymatic manganese(ii) oxidation by a marine alpha-proteobacterium.a yellow-pigmented marine bacterium, designated strain sd-21, was isolated from surface sediments of san diego bay, san diego, calif., based on its ability to oxidize soluble mn(ii) to insoluble mn(iii, iv) oxides. 16s rrna analysis revealed that this organism was most closely related to members of the genus erythrobacter, aerobic anoxygenic phototrophic bacteria within the alpha-4 subgroup of the proteobacteria (alpha-4 proteobacteria). sd-21, however, has a number of distinguishing phenotypic ...200111526000
ribotyping of rhizobia nodulating acacia mangium and paraserianthes falcataria from different geographical areas in indonesia using pcr-rflp-sscp (prs) and sequencing.acacia mangium and paraserianthes falcataria are leguminous tree species widely grown for timber in indonesia and other tropical countries, yet little is known about the identity of their rhizobial symbionts. polymerase chain reaction-restriction fragment length polymorphism-single-strand conformational polymorphism (prs) analysis of the 16s rrna gene was used along with sequencing to assess the diversity of 57 rhizobia isolated from nodules of a. mangium and p. falctaria in indonesia. in total, ...200111359513
an ochrobactrum anthropi gene conferring paraquat resistance to the heterologous host escherichia coli.a new gene, pqra, conferring paraquat resistance to the heterologous host escherichia coli, from a chromosomal dna library of ochrobactrum anthropi jw2, was cloned and analyzed. cells of e. coli transformed with a plasmid carrying the pqra gene showed elevated resistance to paraquat, but not to hydrogen peroxide. the predicted amino acid sequence of the pqra polypeptide showed 71% identity with mll7495 hypothetical membrane protein in mesorhizobium loti, 49% identity with pa2269 protein in pseud ...200111467833
cytokine inducing activities of rhizobial and mesorhizobial lipopolysaccharides of different lethal toxicity.the lethality and cytokines-inducing activity of lipopolysaccharides (lps) obtained from nodulating bacteria, rhizobium leguminosarum and mesorhizobium loti, were compared to those of salmonella typhimurium lps. the activity of r. leguminosarum lps was almost comparable to salmonella endotoxin in terms of lethality, limulus lysate gelating activity and in vivo tumor necrosis factor-alpha (tnf-alpha), interleukin-1beta (il-1beta), interleukin-6 (il-6) and interferon-gamma (ifn-gamma) induction ca ...200011131156
significance of two distinct types of tryptophan synthase beta chain in bacteria, archaea and higher plants.tryptophan synthase consists of two subunits, alpha and beta. two distinct subgroups of beta chain exist. the major group (trpeb_1) includes the well-studied beta chain of salmonella typhimurium. the minor group of beta chain (trpeb_2) is most frequently found in the archaea. most of the amino-acid residues important for catalysis are highly conserved between both trpe subfamilies.200211806827
significance of two distinct types of tryptophan synthase beta chain in bacteria, archaea and higher plants.tryptophan synthase consists of two subunits, alpha and beta. two distinct subgroups of beta chain exist. the major group (trpeb_1) includes the well-studied beta chain of salmonella typhimurium. the minor group of beta chain (trpeb_2) is most frequently found in the archaea. most of the amino-acid residues important for catalysis are highly conserved between both trpe subfamilies.200211806827
identification of the partitioning site within the repabc-type replicon of the composite paracoccus versutus plasmid ptav1.the replicator region of composite plasmid ptav1 of paracoccus versutus (included in mini-replicon ptav320) belongs to the family of repabc replicons commonly found in plasmids harbored by agrobacterium and rhizobium spp. the repabc replicons encode three genes clustered in an operon, which are involved in partitioning (repa and repb) and replication (repc). in order to localize the partitioning site of ptav320, the two identified incompatibility determinants of this mini-replicon (inc1, located ...200111591666
cloning of a genetically unstable cytochrome p-450 gene cluster involved in degradation of the pollutant ethyl tert-butyl ether by rhodococcus ruber.rhodococcus ruber (formerly gordonia terrae) ifp 2001 is one of a few bacterial strains able to degrade ethyl tert-butyl ether (etbe), which is a major pollutant from gasoline. this strain was found to undergo a spontaneous 14.3-kbp chromosomal deletion, which results in the loss of the ability to degrade etbe. sequence analysis of the region corresponding to the deletion revealed the presence of a gene cluster, ethabcd, encoding a ferredoxin reductase, a cytochrome p-450, a ferredoxin, and a 10 ...200111673424
mtnk, methylthioribose kinase, is a starvation-induced protein in bacillus subtilis.methylthioadenosine, the main by-product of spermidine synthesis, is degraded in bacillus subtilis as adenine and methylthioribose. the latter is an excellent sulfur source and the precursor of quorum-sensing signalling molecules. nothing was known about methylthioribose recycling in this organism.200111545674
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