Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| pyd genes of rhizobium sp. strain tal1145 are required for degradation of 3-hydroxy-4-pyridone, an aromatic intermediate in mimosine metabolism. | rhizobium sp. strain tal1145 degrades the leucaena toxin mimosine and its degradation product 3-hydroxy-4-pyridone (hp). the aim of this investigation is to characterize the rhizobium genes for hp degradation and transport. these genes were localized by subcloning and mutagenesis on a previously isolated cosmid, puhr263, containing mid genes of tal1145 required for mimosine degradation. two structural genes, pyda and pydb, encoding a metacleavage dioxygenase and a hydrolase, respectively, are re ... | 2005 | 15968058 |
| the distribution of aquaporin subtypes (pip1, pip2 and gamma-tip) is tissue dependent in soybean (glycine max) root nodules. | background and aims the inner cortical cells (ic-cells) of legume root nodules have been previously shown to regulate the resistance to nodule o2 diffusion by a rapid contraction/expansion mechanism, which controls the volume of intercellular spaces and their occlusion by a liquid phase. the expression of aquaporins in ic-cells was also found to be involved in this nodule o2 diffusion mechanism. the aim of this study was to compare the expression of plasma membrane intrinsic proteins (pip) aquap ... | 2005 | 15987697 |
| escherichia coli hypa is a zinc metalloprotein with a weak affinity for nickel. | the hyp operon encodes accessory proteins that are required for the maturation of the [nife] hydrogenase enzymes and, in some organisms, for the production of urease enzymes as well. hypa or a homologous protein is required for nickel insertion into the hydrogenase precursor proteins. in this study, recombinant hypa from escherichia coli was purified and characterized in vitro. metal analysis was used to demonstrate that hypa simultaneously binds stoichiometric zn(2+) and stoichiometric ni(2+). ... | 2005 | 15995183 |
| genome-wide detection and analysis of cell wall-bound proteins with lpxtg-like sorting motifs. | surface proteins of gram-positive bacteria often play a role in adherence of the bacteria to host tissue and are frequently required for virulence. a specific subgroup of extracellular proteins contains the cell wall-sorting motif lpxtg, which is the target for cleavage and covalent coupling to the peptidoglycan by enzymes called sortases. a comprehensive set of putative sortase substrates was identified by in silico analysis of 199 completely sequenced prokaryote genomes. a combination of detec ... | 2005 | 15995208 |
| purification and characterization of a novel alcohol dehydrogenase from leifsonia sp. strain s749: a promising biocatalyst for an asymmetric hydrogen transfer bioreduction. | to find microorganisms that could reduce phenyl trifluoromethyl ketone (ptk) to (s)-1-phenyltrifluoroethanol [(s)-pte], styrene-assimilating bacteria (ca. 900 strains) isolated from soil samples were screened. we found that leifsonia sp. strain s749 was the most suitable strain for the conversion of ptk to (s)-pte in the presence of 2-propanol as a hydrogen donor. the enzyme corresponding to the reaction was purified homogeneity, characterized and designated leifsonia alcohol dehydrogenase (lsad ... | 2005 | 16000771 |
| l: -stereoselective amino acid amidase with broad substrate specificity from brevundimonas diminuta: characterization of a new member of the leucine aminopeptidase family. | brevundimonas diminuta tpu 5720 produces an amidase acting l-stereoselectively on phenylalaninamide. the enzyme (laaa(bd)) was purified to electrophoretic homogeneity by ammonium sulfate fractionation and four steps of column chromatography. the final preparation gave a single band on sds-page with a molecular weight of approximately 53,000. the native molecular weight of the enzyme was about 288,000 based on gel filtration chromatography, suggesting that the enzyme is active as a homohexamer. i ... | 2006 | 16001251 |
| srsymrk, a plant receptor essential for symbiosome formation. | the symbiosis between legumes and rhizobia is essential for the nitrogen input into the life cycle on our planet. new root organs, the nodules, are established, which house n2-fixing bacteria internalized into the host cell cytoplasm as horizontally acquired organelles, the symbiosomes. the interaction is initiated by bacterial invasion via epidermal root hair curling and cell division in the cortex, both triggered by bacterial nodulation factors. of the several genes involved in nodule initiati ... | 2005 | 16006516 |
| origin and evolution of the archaeo-eukaryotic primase superfamily and related palm-domain proteins: structural insights and new members. | we report an in-depth computational study of the protein sequences and structures of the superfamily of archaeo-eukaryotic primases (aeps). this analysis greatly expands the range of diversity of the aeps and reveals the unique active site shared by all members of this superfamily. in particular, it is shown that eukaryotic nucleo-cytoplasmic large dna viruses, including poxviruses, asfarviruses, iridoviruses, phycodnaviruses and the mimivirus, encode aeps of a distinct family, which also includ ... | 2005 | 16027112 |
| variant tricarboxylic acid cycle in mycobacterium tuberculosis: identification of alpha-ketoglutarate decarboxylase. | mycobacterium tuberculosis (mtb) has adapted its metabolism for persistence in the human macrophage. the adaptations are likely to involve mtb's core intermediary metabolism, whose enzymes have been little studied. the tricarboxylic acid cycle is expected to yield precursors for energy, lipids, amino acids, and heme. the genome sequence of mtb h37rv predicts the presence of a complete tricarboxylic acid cycle, but we recently found that alpha-ketoglutarate dehydrogenase (kdh) activity is lacking ... | 2005 | 16027371 |
| the stringent response is required for amino acid and nitrate utilization, nod factor regulation, nodulation, and nitrogen fixation in rhizobium etli. | a rhizobium etli tn5 insertion mutant, lm01, was selected for its inability to use glutamine as the sole carbon and nitrogen source. the tn5 insertion in lm01 was localized to the rsh gene, which encodes a member of the rela/spot family of proteins. the lm01 mutant was affected in the ability to use amino acids and nitrate as nitrogen sources and was unable to accumulate (p)ppgpp when grown under carbon and nitrogen starvation, as opposed to the wild-type strain, which accumulated (p)ppgpp under ... | 2005 | 16030199 |
| iron-dependent cytochrome c1 expression is mediated by the status of heme in bradyrhizobium japonicum. | the heme prosthetic group of heme proteins contains iron, which can be a limiting nutrient. here, we show that cytochrome c1 protein from bradyrhizobium japonicum was strongly affected by the iron status, with low expression in cells grown under iron limitation. this control was not affected in mutants encoding the iron regulator irr or fur. furthermore, cytochrome c1 mrna was not influenced by the iron status, suggesting control at a posttranscriptional step. cytochrome c1 protein levels were v ... | 2005 | 16030200 |
| use of suppression-subtractive hybridization to identify genes in the burkholderia cepacia complex that are unique to burkholderia cenocepacia. | we have previously shown differences in virulence between species of the burkholderia cepacia complex using the alfalfa infection model and the rat agar bead chronic infection model. burkholderia cenocepacia strains were more virulent in these two infection models than burkholderia multivorans and burkholderia stabilis strains. in order to identify genes that may account for the increased virulence of b. cenocepacia, suppression-subtractive hybridization was performed between b. cenocepacia k56- ... | 2005 | 16030222 |
| de novo alanine synthesis by bacteroids of mesorhizobium loti is not required for nitrogen transfer in the determinate nodules of lotus corniculatus. | deletion of both alanine dehydrogenase genes (alda) in mesorhizobium loti resulted in the loss of alda enzyme activity from cultured bacteria and bacteroids but had no effect on the symbiotic performance of lotus corniculatus plants. thus, neither indeterminate pea nodules nor determinate l. corniculatus nodules export alanine as the sole nitrogen secretion product. | 2005 | 16030244 |
| a computational approach for identifying pathogenicity islands in prokaryotic genomes. | pathogenicity islands (pais), distinct genomic segments of pathogens encoding virulence factors, represent a subgroup of genomic islands (gis) that have been acquired by horizontal gene transfer event. up to now, computational approaches for identifying pais have been focused on the detection of genomic regions which only differ from the rest of the genome in their base composition and codon usage. these approaches often lead to the identification of genomic islands, rather than pais. | 2005 | 16033657 |
| the role of molybdenum in agricultural plant production. | the importance of molybdenum for plant growth is disproportionate with respect to the absolute amounts required by most plants. apart from cu, mo is the least abundant essential micronutrient found in most plant tissues and is often set as the base from which all other nutrients are compared and measured. molybdenum is utilized by selected enzymes to carry out redox reactions. enzymes that require molybdenum for activity include nitrate reductase, xanthine dehydrogenase, aldehyde oxidase and sul ... | 2005 | 16033776 |
| characterization of conformational changes coupled to ligand photodissociation from the heme binding domain of fixl. | using transient absorption spectroscopy and photoacoustic calorimetry (pac), we have characterized carbon monoxide photodissociation and rebinding to two forms of the heme domain of bradyrhizobium japonicum fixl. transient absorption results for the complete heme domain (fixl residues 140-270) and a truncated heme domain (missing 11 residues on the n-teminal end and 14 amino acid residues on the c-terminal end of the full length heme domain) show similar rates for ligand rebinding to the five-co ... | 2005 | 16042379 |
| characterization and calculation of a cytochrome c-cytochrome b5 complex using nmr data. | to identify the binding site for bovine cytochrome b(5) (cyt b(5)) on horse cytochrome c (cyt c), cross-saturation transfer nmr experiments were performed with (2)h- and (15)n-enriched cyt c and unlabeled cyt b(5). in addition, chemical shift changes of the cyt c backbone amide and side chain methyl resonances were monitored as a function of cyt b(5) concentration. the chemical shift changes indicate that the complex is in fast exchange, and are consistent with a 1:1 stoichiometry. a k(a) of (4 ... | 2005 | 16060674 |
| comparative analyses of codon and amino acid usage in symbiotic island and core genome in nitrogen-fixing symbiotic bacterium bradyrhizobium japonicum. | genes involved in the symbiotic interactions between the nitrogen-fixing endosymbiont bradyrhizobium japonicum, and its leguminous host are mostly clustered in a symbiotic island (si), acquired by the bacterium through a process of horizontal transfer. a comparative analysis of the codon and amino acid usage in core and si genes/proteins of b. japonicum has been carried out in the present study. the mutational bias, translational selection, and gene length are found to be the major sources of va ... | 2005 | 16060695 |
| carboxyl-terminal protease regulates brucella suis morphology in culture and persistence in macrophages and mice. | the putative carboxyl-terminal processing protease (ctpa) of brucella suis 1330 is a member of a novel family of endoproteases involved in the maturation of proteins destined for the cell envelope. the b. suis ctpa protein shared up to 77% homology with ctpa proteins of other bacteria. a ctpa-deficient brucella strain (1330deltactpa), generated by allelic exchange, produced smaller colonies on enriched agar plates and exhibited a 50% decrease in growth rate in enriched liquid medium and no growt ... | 2005 | 16077124 |
| two rhizobial strains, mesorhizobium loti maff303099 and bradyrhizobium japonicum usda110, encode haloalkane dehalogenases with novel structures and substrate specificities. | haloalkane dehalogenases are key enzymes for the degradation of halogenated aliphatic pollutants. two rhizobial strains, mesorhizobium loti maff303099 and bradyrhizobium japonicum usda110, have open reading frames (orfs), mlr5434 and blr1087, respectively, that encode putative haloalkane dehalogenase homologues. the crude extracts of escherichia coli strains expressing mlr5434 and blr1087 showed the ability to dehalogenate 18 halogenated compounds, indicating that these orfs indeed encode haloal ... | 2005 | 16085827 |
| expression of nitrite and nitric oxide reductases in free-living and plant-associated agrobacterium tumefaciens c58 cells. | a number of the bacteria that form associations with plants are denitrifiers. to learn more about how the association with plants affects expression of denitrification genes, the regulation of nitrite and nitric oxide reductases was investigated in agrobacterium tumefaciens. analysis of free-living cells revealed that expression of the genes encoding nitrite and nitric oxide reductases, nirk and nor, respectively, requires low-oxygen conditions, nitric oxide, and the transcriptional regulator nn ... | 2005 | 16085833 |
| allophanate hydrolase, not urease, functions in bacterial cyanuric acid metabolism. | growth substrates containing an s-triazine ring are typically metabolized by bacteria to liberate 3 mol of ammonia via the intermediate cyanuric acid. over a 25-year period, a number of original research papers and reviews have stated that cyanuric acid is metabolized in two steps to the 2-nitrogen intermediate urea. in the present study, allophanate, not urea, was shown to be the 2-nitrogen intermediate in cyanuric acid metabolism in all the bacteria examined. six different experimental results ... | 2005 | 16085834 |
| isolation and characterization of a genetically tractable photoautotrophic fe(ii)-oxidizing bacterium, rhodopseudomonas palustris strain tie-1. | we report the isolation and characterization of a phototrophic ferrous iron [fe(ii)]-oxidizing bacterium named tie-1 that differs from other fe(ii)-oxidizing phototrophs in that it is genetically tractable. under anaerobic conditions, tie-1 grows photoautotrophically with fe(ii), h2, or thiosulfate as the electron donor and photoheterotrophically with a variety of organic carbon sources. tie-1 also grows chemoheterotrophically in the dark. this isolate appears to be a new strain of the purple no ... | 2005 | 16085840 |
| transcriptome-based identification of the sinorhizobium meliloti nodd1 regulon. | the nodd1 regulon of sinorhizobium meliloti was determined through the analysis of the s. meliloti transcriptome in response to the plant flavone luteolin and the overexpression of nodd1. nine new genes regulated by both nodd1 and luteolin were identified, demonstrating that nodd1 controls few functions behind nodulation in s. meliloti. | 2005 | 16085895 |
| identification of genes involved in cytochrome c biogenesis in shewanella oneidensis, using a modified mariner transposon. | a modified mariner transposon, minihimar rb1, was generated to mutagenize cells of the metal-reducing bacterium shewanella oneidensis. the use of this transposon led to the isolation of stable mutants and allowed rapid identification of disrupted genes. fifty-eight mutants, including bg104 and bg148 with transposon insertions in the cytochrome c maturation genes ccmc and ccmf1, respectively, were analyzed. both mutants were deficient in anaerobic respiration and cytochrome c production. | 2005 | 16085900 |
| evidence for a second class of s-adenosylmethionine riboswitches and other regulatory rna motifs in alpha-proteobacteria. | riboswitches are rna elements in the 5' untranslated leaders of bacterial mrnas that directly sense the levels of specific metabolites with a structurally conserved aptamer domain to regulate expression of downstream genes. riboswitches are most common in the genomes of low gc gram-positive bacteria (for example, bacillus subtilis contains examples of all known riboswitches), and some riboswitch classes seem to be restricted to this group. | 2005 | 16086852 |
| a phylogeny of bacterial rna nucleotidyltransferases: bacillus halodurans contains two trna nucleotidyltransferases. | we have analyzed the distribution of rna nucleotidyltransferases from the family that includes poly(a) polymerases (pap) and trna nucleotidyltransferases (tnt) in 43 bacterial species. genes of several bacterial species encode only one member of the nucleotidyltransferase superfamily (ntsf), and if that protein functions as a tnt, those organisms may not contain a poly(a) polymerase i like that of escherichia coli. the genomes of several of the species examined encode more than one member of the ... | 2005 | 16109934 |
| cytochrome c maturation and the physiological role of c-type cytochromes in vibrio cholerae. | vibrio cholerae lives in different habitats, varying from aquatic ecosystems to the human intestinal tract. the organism has acquired a set of electron transport pathways for aerobic and anaerobic respiration that enable adaptation to the various environmental conditions. we have inactivated the v. cholerae ccme gene, which is required for cytochrome c biogenesis. the resulting strain is deficient of all c-type cytochromes and allows us to characterize the physiological role of these proteins. u ... | 2005 | 16109941 |
| e1 enzyme of the pyruvate dehydrogenase complex in corynebacterium glutamicum: molecular analysis of the gene and phylogenetic aspects. | the e1p enzyme is an essential part of the pyruvate dehydrogenase complex (pdhc) and catalyzes the oxidative decarboxylation of pyruvate with concomitant acetylation of the e2p enzyme within the complex. we analyzed the corynebacterium glutamicum acee gene, encoding the e1p enzyme, and constructed and characterized an e1p-deficient mutant. sequence analysis of the c. glutamicum acee gene and adjacent regions revealed that acee is not flanked by genes encoding other enzymes of the pdhc. transcrip ... | 2005 | 16109942 |
| identification of a new family of enzymes with potential o-acetylpeptidoglycan esterase activity in both gram-positive and gram-negative bacteria. | the metabolism of the rigid bacterial cell wall heteropolymer peptidoglycan is a dynamic process requiring continuous biosynthesis and maintenance involving the coordination of both lytic and synthetic enzymes. the o-acetylation of peptidoglycan has been proposed to provide one level of control on these activities as this modification inhibits the action of the major endogenous lytic enzymes, the lytic transglycosylases. the o-acetylation of peptidoglycan also inhibits the activity of the lysozy ... | 2005 | 16111493 |
| helicobacter hepaticus hydrogenase mutants are deficient in hydrogen-supported amino acid uptake and in causing liver lesions in a/j mice. | helicobacter hepaticus, a causative agent of chronic hepatitis and hepatocellular carcinoma in mice, expresses a nickel-containing hydrogen-oxidizing hydrogenase enzyme. growth of a hyab gene-targeted mutant was unaffected by the presence of hydrogen, unlike the wild-type strain, which showed an enhanced growth rate when supplied with h(2). hydrogenase activities in h. hepaticus were constitutive and not dependent on the inclusion of h(2) during growth. addition of nickel during growth significa ... | 2005 | 16113246 |
| compared tolerance to osmotic stress in various microorganisms: towards a survival prediction test. | the osmotic tolerance of microbial cells of different microorganisms was investigated as a function of glycerol concentration and temperatures. cells displayed specific sensitivity to dehydration in glycerol solutions. the viability of gram-negative strains (escherichia coli, bradyrhizobium japonicum), gram-positive strains (lactobacillus plantarum, l. bulgaricus), and yeasts (saccharomyces cerevisiae, candida utilis) decreased with increasing osmotic pressure. for each strain, a characteristic ... | 2005 | 16116658 |
| comparative analyses of fundamental differences in membrane transport capabilities in prokaryotes and eukaryotes. | whole-genome transporter analyses have been conducted on 141 organisms whose complete genome sequences are available. for each organism, the complete set of membrane transport systems was identified with predicted functions, and classified into protein families based on the transporter classification system. organisms with larger genome sizes generally possessed a relatively greater number of transport systems. in prokaryotes and unicellular eukaryotes, the significant factor in the increase in ... | 2005 | 16118665 |
| characterization and expression analysis of the groesl operon of bartonella bacilliformis. | the groesl operon of bartonella bacilliformis, a facultative intracellular, gram-negative bacterium and etiologic agent of oroya fever, was characterized. sequence analysis revealed an operon containing two genes of 294 (groes) and 1632 nucleotides (groel) separated by a 55-nt intergenic spacer. the operon is preceded by a 72-nt orf (orf1) that encodes a hypothetical protein with homology to a portion of the hrca repressor for groesl. a divergent fumarate hydratase c (fumc) gene lies further ups ... | 2005 | 16126349 |
| comparative and evolutionary analysis of the bacterial homologous recombination systems. | homologous recombination is a housekeeping process involved in the maintenance of chromosome integrity and generation of genetic variability. although detailed biochemical studies have described the mechanism of action of its components in model organisms, there is no recent extensive assessment of this knowledge, using comparative genomics and taking advantage of available experimental data on recombination. using comparative genomics, we assessed the diversity of recombination processes among ... | 2005 | 16132081 |
| detection of homoserine lactone-like quorum sensing molecules in bradyrhizobium strains. | one hundred and forty-two bradyrhizobium strains were screened for their ability to produce n-acyl homoserine lactone-like molecules (ahls) by using an agrobacterium tumefaciens biosensor strain containing a trai-lacz fusion. approximately 22% (31 of 142) of the tested strains produced ahls that induced moderate to elevated beta-galactosidase activity levels in the biosensor strain. bradyrhizobium japonicum and bradyrhizobium elkanii strains were both shown to produce ahls. age of culture, and m ... | 2005 | 16132457 |
| structure and sequence conservation of hao cluster genes of autotrophic ammonia-oxidizing bacteria: evidence for their evolutionary history. | comparison of the organization and sequence of the hao (hydroxylamine oxidoreductase) gene clusters from the gammaproteobacterial autotrophic ammonia-oxidizing bacterium (aaob) nitrosococcus oceani and the betaproteobacterial aaob nitrosospira multiformis and nitrosomonas europaea revealed a highly conserved gene cluster encoding the following proteins: hao, hydroxylamine oxidoreductase; orf2, a putative protein; cyca, cytochrome c(554); and cycb, cytochrome c(m)(552). the deduced protein sequen ... | 2005 | 16151127 |
| cog3926 and cog5526: a tale of two new lysozyme-like protein families. | we have identified two new lysozyme-like protein families by using a combination of sequence similarity searches, domain architecture analysis, and structural predictions. first, the p5 protein from bacteriophage phi8, which belongs to cog3926 and pfam family duf847, is predicted to have a new lysozyme-like domain. this assignment is consistent with the lytic function of p5 proteins observed in several related double-stranded rna bacteriophages. domain architecture analysis reveals two lysozyme- ... | 2005 | 16155206 |
| expression and characterization of a histidine-rich protein, hpn: potential for ni2+ storage in helicobacter pylori. | hpn is a small cytoplasmic protein found in helicobacter pylori, which binds ni2+ ions with moderate affinity. consisting of 60 amino acids, the protein is rich in histidine (28 residues, 46.7%), as well as glutamate, glycine and serine residues (in total 31.7%), and contains short repeating motifs. in the present study, we report the detailed biophysical characterization of the multimeric status and ni2+-binding properties of purified recombinant hpn under physiologically relevant conditions. t ... | 2006 | 16164421 |
| expression and characterization of a histidine-rich protein, hpn: potential for ni2+ storage in helicobacter pylori. | hpn is a small cytoplasmic protein found in helicobacter pylori, which binds ni2+ ions with moderate affinity. consisting of 60 amino acids, the protein is rich in histidine (28 residues, 46.7%), as well as glutamate, glycine and serine residues (in total 31.7%), and contains short repeating motifs. in the present study, we report the detailed biophysical characterization of the multimeric status and ni2+-binding properties of purified recombinant hpn under physiologically relevant conditions. t ... | 2006 | 16164421 |
| an iron uptake operon required for proper nodule development in the bradyrhizobium japonicum-soybean symbiosis. | rhizobia live in the soil or enter into a nitrogen-fixing symbiosis with a suitable host plant. each environment presents different challenges with respect to iron acquisition. the soybean symbiont bradyrhizobium japonicum 61a152 can utilize a variety of siderophores (fe[iii]-specific ligands). purification of iron-regulated outer membrane proteins had previously allowed the cloning of a gene, fega, from b. japonicum 61a152, whose predicted protein shares significant amino acid similarity with k ... | 2005 | 16167765 |
| diversity in domain architectures of ser/thr kinases and their homologues in prokaryotes. | ser/thr/tyr kinases (styks) commonly found in eukaryotes have been recently reported in many bacterial species. recent studies elucidating their cellular functions have established their roles in bacterial growth and development. however functions of a large number of bacterial styks still remain elusive. the organisation of domains in a large dataset of bacterial styks has been investigated here in order to recognise variety in domain combinations which determine functions of bacterial styks. | 2005 | 16171520 |
| two-component signal transduction pathways regulating growth and cell cycle progression in a bacterium: a system-level analysis. | two-component signal transduction systems, comprised of histidine kinases and their response regulator substrates, are the predominant means by which bacteria sense and respond to extracellular signals. these systems allow cells to adapt to prevailing conditions by modifying cellular physiology, including initiating programs of gene expression, catalyzing reactions, or modifying protein-protein interactions. these signaling pathways have also been demonstrated to play a role in coordinating bact ... | 2005 | 16176121 |
| highways of gene sharing in prokaryotes. | the extent to which lateral genetic transfer has shaped microbial genomes has major implications for the emergence of community structures. we have performed a rigorous phylogenetic analysis of >220,000 proteins from genomes of 144 prokaryotes to determine the contribution of gene sharing to current prokaryotic diversity, and to identify "highways" of sharing between lineages. the inferred relationships suggest a pattern of inheritance that is largely vertical, but with notable exceptions among ... | 2005 | 16176988 |
| successful selection of cross-protective vaccine candidates for ornithobacterium rhinotracheale infection. | ornithobacterium rhinotracheale is a bacterial pathogen known for causing respiratory disease in poultry. in this study, we demonstrate for the first time that cross-protective immunity against different o. rhinotracheale serotypes can be induced by live vaccination. sera from these live-vaccinated and cross-protected birds were used to identify new vaccine targets by screening an o. rhinotracheale expression library. out of 20,000 screened plaques, a total of 30 cross-reactive clones were selec ... | 2005 | 16177359 |
| ethe1 mutations are specific to ethylmalonic encephalopathy. | mutations in ethe1, a gene located at chromosome 19q13, have recently been identified in patients affected by ethylmalonic encephalopathy (ee). ee is a devastating infantile metabolic disorder, characterised by widespread lesions in the brain, hyperlactic acidaemia, petechiae, orthostatic acrocyanosis, and high levels of ethylmalonic acid in body fluids. to investigate to what extent ethe1 is responsible for ee, we analysed this gene in 29 patients with typical ee and in 11 patients presenting w ... | 2006 | 16183799 |
| ethe1 mutations are specific to ethylmalonic encephalopathy. | mutations in ethe1, a gene located at chromosome 19q13, have recently been identified in patients affected by ethylmalonic encephalopathy (ee). ee is a devastating infantile metabolic disorder, characterised by widespread lesions in the brain, hyperlactic acidaemia, petechiae, orthostatic acrocyanosis, and high levels of ethylmalonic acid in body fluids. to investigate to what extent ethe1 is responsible for ee, we analysed this gene in 29 patients with typical ee and in 11 patients presenting w ... | 2006 | 16183799 |
| nh4+ currents across the peribacteroid membrane of soybean. macroscopic and microscopic properties, inhibition by mg2+, and temperature dependence indicate a subpicosiemens channel finely regulated by divalent cations. | the control of ammonium (nh(4)(+)) transport is critical in preventing futile cycles of nh(4)(+)/ammonia transport. an unusual nonselective cation channel with subpicosiemens single-channel conductance permeable to nh(4)(+) had previously been identified in the peribacteroid membrane (pbm) of symbiosomes from soybean (glycine max) nodules. here, we investigate the proposed channel mechanism and its control by luminal magnesium. currents carried by nh(4)(+) were measured in inside-out pbm patches ... | 2005 | 16183839 |
| gene products of the hupghij operon are involved in maturation of the iron-sulfur subunit of the [nife] hydrogenase from rhizobium leguminosarum bv. viciae. | in the present study, we investigate the functions of the hupghij operon in the synthesis of an active [nife] hydrogenase in the legume endosymbiont rhizobium leguminosarum bv. viciae. these genes are clustered with 14 other genes including the hydrogenase structural genes hupsl. a set of isogenic mutants with in-frame deletions (deltahupg, deltahuph, deltahupi, and deltahupj) was generated and tested for hydrogenase activity in cultures grown at different oxygen concentrations (0.2 to 2.0%) and ... | 2005 | 16199572 |
| biosynthesis of active bacillus subtilis urease in the absence of known urease accessory proteins. | bacillus subtilis contains urease structural genes but lacks the accessory genes typically required for gtp-dependent incorporation of nickel. nevertheless, b. subtilis was shown to possess a functional urease, and the recombinant enzyme conferred low levels of nickel-dependent activity to escherichia coli. additional investigations of the system lead to the suggestion that b. subtilis may use unidentified accessory proteins for in vivo urease activation. | 2005 | 16199586 |
| role of the regulatory gene rira in the transcriptional response of sinorhizobium meliloti to iron limitation. | a regulatory network of sinorhizobium meliloti genes involved in adaptation to iron-limiting conditions and the involvement of the rhizobial iron regulator gene (rira) were analyzed by mutation and microarray analyses. a constructed s. meliloti rira mutant exhibited growth defects and enhanced h2o2 sensitivity in the presence of iron, but symbiotic nitrogen fixation was not affected. to identify iron-responsive and rira-regulated s. meliloti genes, a transcriptome approach using whole-genome mic ... | 2005 | 16204511 |
| dimeric brucella abortus irr protein controls its own expression and binds haem. | brucella abortus needs to synthesize haem in order to replicate intracellularly and to produce virulence in mice. thus, to gain insight into the pathogenesis of the bacterium, regulatory proteins of the haem biosynthetic pathway were sought. an iron response regulator (irr) from bradyrhizobium japonicum, which is a close relative of brucella, was previously described as being involved in the coordination of haem biosynthesis and iron availability. the bru. abortus genome was searched for an irr ... | 2005 | 16207924 |
| the crystal structure of mismatch-specific uracil-dna glycosylase (mug) from deinococcus radiodurans reveals a novel catalytic residue and broad substrate specificity. | deinococcus radiodurans is extremely resistant to the effects of ionizing radiation. the source of the radiation resistance is not known, but an expansion of specific protein families related to stress response and damage control has been observed. dna repair enzymes are among the expanded protein families in d. radiodurans, and genes encoding five different uracil-dna glycosylases are identified in the genome. here we report the three-dimensional structure of the mismatch-specific uracil-dna gl ... | 2006 | 16223719 |
| differentiation of regions with atypical oligonucleotide composition in bacterial genomes. | complete sequencing of bacterial genomes has become a common technique of present day microbiology. thereafter, data mining in the complete sequence is an essential step. new in silico methods are needed that rapidly identify the major features of genome organization and facilitate the prediction of the functional class of orfs. we tested the usefulness of local oligonucleotide usage (ou) patterns to recognize and differentiate types of atypical oligonucleotide composition in dna sequences of ba ... | 2005 | 16225667 |
| evolutionary, structural and functional relationships revealed by comparative analysis of syntenic genes in rhizobiales. | comparative genomics has provided valuable insights into the nature of gene sequence variation and chromosomal organization of closely related bacterial species. however, questions about the biological significance of gene order conservation, or synteny, remain open. moreover, few comprehensive studies have been reported for rhizobial genomes. | 2005 | 16229745 |
| analysis of genetic relationship of sarothamnus scoparius microsymbionts and bradyrhizobium sp. by hybridization in microdilution wells. | dna-dna hybridization in microdilution wells was successfully used to determine the overall genomic similarity among sarothamnus scoparius microsymbionts isolated from poland and japan and representatives of bradyrhizobium species including bradyrhizobium sp. (lupinus) usda3045. geographically different s. scoparius rhizobia diverged into two genomospecies at the dna-dna similarity level of approximately 49%. polish isolates exhibited high dna similarity levels to the dna of bradyrhizobium japon ... | 2004 | 16233609 |
| atccmh, an essential component of the c-type cytochrome maturation pathway in arabidopsis mitochondria, interacts with apocytochrome c. | the maturation of c-type cytochromes requires the covalent ligation of the heme cofactor to reduced cysteines of the cxxch motif of apocytochromes. in contrast to mitochondria of other eukaryotes, plant mitochondria follow a pathway close to that found in alpha- and gamma-proteobacteria. we identified a nuclear-encoded protein, atccmh, the arabidopsis thaliana ortholog of bacterial ccmh/cycl proteins. in bacteria, ccmh and the thioredoxin ccmg are components of a periplasmic thio-reduction pathw ... | 2005 | 16236729 |
| diversification of dna sequences in the symbiotic genome of rhizobium etli. | bacteria of the genus rhizobium and related genera establish nitrogen-fixing symbioses with the roots of leguminous plants. the genetic elements that participate in the symbiotic process are usually compartmentalized in the genome, either as independent replicons (symbiotic plasmids) or as symbiotic regions or islands in the chromosome. the complete nucleotide sequence of the symbiotic plasmid of rhizobium etli model strain cfn42, symbiont of the common bean plant, has been reported. to better u ... | 2005 | 16237002 |
| oligomerization of sulfolobus solfataricus signature amidase is promoted by acidic ph and high temperature. | the recombinant amidase from the hyperthermophylic archaeon sulfolobus solfataricus (ssam) a signature amidase, was cloned, purified and characterized. the enzyme is active on a large number of aliphatic and aromatic amides over the temperature range 60-95 degrees c and at ph values between 4.0 and 9.5, with an optimum at ph 5.0. the recombinant enzyme is in the form of a dimer of about 110 kd that reversibly associates into an octamer in a ph-dependent reaction. the ph dependence of the state o ... | 2005 | 16243781 |
| expansion of the biocyc collection of pathway/genome databases to 160 genomes. | the biocyc database collection is a set of 160 pathway/genome databases (pgdbs) for most eukaryotic and prokaryotic species whose genomes have been completely sequenced to date. each pgdb in the biocyc collection describes the genome and predicted metabolic network of a single organism, inferred from the metacyc database, which is a reference source on metabolic pathways from multiple organisms. in addition, each bacterial pgdb includes predicted operons for the corresponding species. the biocyc ... | 2005 | 16246909 |
| [effect of plant growth regulators on physiological activity of bradyrhizobium japonicum ]. | influence of plant growth regulators ivin, emistim c, eney and agrostimulin on the biomass production and exopolymers synthesis of soybean nodule bacteria, which have contrasting symbiotic properties, and glutamine synthetase activity of their cell-free extracts were studied. it was shown that the processes of the biomass and exopolymers accumulation had an opposite direction. of all preparations only ivin and agrostimulin intensificol growth activity of the microorganisms under study. the level ... | 2005 | 16250234 |
| global protein expression pattern of bradyrhizobium japonicum bacteroids: a prelude to functional proteomics. | as a prelude to using functional proteomics towards understanding the process of symbiotic nitrogen fixation between the legume soybean and the soil bacteria bradyrhizobium japonicum, we examined the total protein expression pattern of the nodule bacteria, often referred to as bacteroids. a partial proteome map was constructed by separating the total bacteroid proteins using high-resolution 2-de. of the several hundred protein spots analyzed using pmf, 180 spots were tentatively identified by se ... | 2005 | 16254929 |
| dissimilatory metabolism of nitrogen oxides in bacteria: comparative reconstruction of transcriptional networks. | bacterial response to nitric oxide (no) is of major importance since no is an obligatory intermediate of the nitrogen cycle. transcriptional regulation of the dissimilatory nitric oxides metabolism in bacteria is diverse and involves fnr-like transcription factors hcpr, dnr, and nnrr; two-component systems narxl and narqp; no-responsive activator norr; and nitrite-sensitive repressor nsrr. using comparative genomics approaches, we predict dna-binding motifs for these transcriptional factors and ... | 2005 | 16261196 |
| diversity of "candidatus liberibacter asiaticus," based on the omp gene sequence. | huanglongbing (yellow dragon disease) is a destructive disease of citrus. the etiological agent is a noncultured, phloem-restricted alpha-proteobacterium, "candidatus liberibacter africanus" in africa and "candidatus liberibacter asiaticus" in asia. in this study, we used an omp-based pcr-restriction fragment length polymorphism (rflp) approach to analyze the genetic variability of "ca. liberibacter asiaticus" isolates. by using five different enzymes, each the 10 isolates tested could be associ ... | 2005 | 16269671 |
| european origin of bradyrhizobium populations infecting lupins and serradella in soils of western australia and south africa. | we applied a multilocus phylogenetic approach to elucidate the origin of serradella and lupin bradyrhizobium strains that persist in soils of western australia and south africa. the selected strains belonged to different randomly amplified polymorphic dna (rapd)-pcr clusters that were distinct from rapd clusters of applied inoculant strains. phylogenetic analyses were performed with nodulation genes (noda, nodz, noll, noei), housekeeping genes (dnak, reca, glnii, atpd), and 16s-23s rrna intergen ... | 2005 | 16269740 |
| new findings on evolution of metal homeostasis genes: evidence from comparative genome analysis of bacteria and archaea. | in order to examine the natural history of metal homeostasis genes in prokaryotes, open reading frames with homology to characterized p(ib)-type atpases from the genomes of 188 bacteria and 22 archaea were investigated. major findings were as follows. first, a high diversity in n-terminal metal binding motifs was observed. these motifs were distributed throughout bacterial and archaeal lineages, suggesting multiple loss and acquisition events. second, the copa locus separated into two distinct p ... | 2005 | 16269744 |
| novel dna sequences from natural strains of the nitrogen-fixing symbiotic bacterium sinorhizobium meliloti. | variation in genome size and content is common among bacterial strains. identifying these naturally occurring differences can accelerate our understanding of bacterial attributes, such as ecological specialization and genome evolution. in this study, we used representational difference analysis to identify potentially novel sequences not present in the sequenced laboratory strain rm1021 of the nitrogen-fixing bacterium sinorhizobium meliloti. using strain rm1021 as the driver and the type strain ... | 2005 | 16269751 |
| three stages of a biofilm community developing at the liquid-liquid interface between polychlorinated biphenyls and water. | soil contaminated with polychlorinated biphenyls (pcb) was used as an inoculum to grow a complex biofilm community on pcb oil (aroclor 1242) on a substratum (permanox). the biofilm was monitored for 31 days by confocal laser scanning microscopy, community fingerprinting using single-strand conformational polymorphism (sscp), amplicons of the 16s rrna genes, and chemical analyses of the pcb congeners. sscp analysis of the young biofilm revealed a rather diverse microbial community with species of ... | 2005 | 16269772 |
| rhodopseudomonas palustris regulons detected by cross-species analysis of alphaproteobacterial genomes. | rhodopseudomonas palustris, an alpha-proteobacterium, carries out three of the chemical reactions that support life on this planet: the conversion of sunlight to chemical-potential energy; the absorption of carbon dioxide, which it converts to cellular material; and the fixation of atmospheric nitrogen into ammonia. insight into the transcription-regulatory network that coordinates these processes is fundamental to understanding the biology of this versatile bacterium. with this goal in mind, we ... | 2005 | 16269786 |
| proof that burkholderia strains form effective symbioses with legumes: a study of novel mimosa-nodulating strains from south america. | twenty mimosa-nodulating bacterial strains from brazil and venezuela, together with eight reference mimosa-nodulating rhizobial strains and two other beta-rhizobial strains, were examined by amplified rrna gene restriction analysis. they fell into 16 patterns and formed a single cluster together with the known beta-rhizobia, burkholderia caribensis, burkholderia phymatum, and burkholderia tuberum. the 16s rrna gene sequences of 15 of the 20 strains were determined, and all were shown to belong t ... | 2005 | 16269788 |
| first genome data from uncultured upland soil cluster alpha methanotrophs provide further evidence for a close phylogenetic relationship to methylocapsa acidiphila b2 and for high-affinity methanotrophy involving particulate methane monooxygenase. | members of upland soil cluster alpha (usc alpha) are assumed to be methanotrophic bacteria (mb) adapted to the trace level of atmospheric methane. so far, these mb have eluded all cultivation attempts. while the 16s rrna phylogeny of usc alpha members is still not known, phylogenies constructed for the active-site polypeptide (encoded by pmoa) of particulate methane monooxygenase (pmmo) placed usc alpha next to the alphaproteobacterial methylocapsa acidiphila b2. to assess whether the pmoa tree ... | 2005 | 16269789 |
| symbiotic hydrogenase activity in bradyrhizobium sp. (vigna) increases nitrogen content in vigna unguiculata plants. | bradyrhizobium sp. (lupinus) and bradyrhizobium sp. (vigna) mutants in which hydrogenase (hup) activity was affected were constructed and analyzed. vigna unguiculata plants inoculated with the bradyrhizobium sp. (vigna) hup mutant showed reduced nitrogenase activity and also a significant decrease in nitrogen content, suggesting a relevant contribution of hydrogenase activity to plant yield. | 2005 | 16269797 |
| characterization of temporal protein production in pseudomonas aeruginosa biofilms. | phenotypic and genetic evidence supporting the notion of biofilm formation as a developmental process is growing. in the present work, we provide additional support for this hypothesis by identifying the onset of accumulation of biofilm-stage specific proteins during pseudomonas aeruginosa biofilm maturation and by tracking the abundance of these proteins in planktonic and three biofilm developmental stages. the onset of protein production was found to correlate with the progression of biofilms ... | 2005 | 16291684 |
| induction of thioredoxin is required for nodule development to reduce reactive oxygen species levels in soybean roots. | nodules are formed on legume roots as a result of signaling between symbiotic partners and in response to the activities of numerous genes. we cloned fragments of differentially expressed genes in spot-inoculated soybean (glycine max) roots. many of the induced clones were similar to known genes related to oxidative stress, such as thioredoxin and beta-carotene hydroxylase. the deduced amino acid sequences of full-length soybean cdnas for thioredoxin and beta-carotene hydroxylase were similar to ... | 2005 | 16299179 |
| four-helix bundle: a ubiquitous sensory module in prokaryotic signal transduction. | motivation: transmembrane chemoreceptors in escherichia coli utilize ligand-binding domains for detecting various external signals. the structure of this domain in the e.coli aspartate receptor, tar, is known and its signal transduction mechanism is under investigation. current domain models for this important sensory module are inaccurate and, therefore, cannot reveal the distribution of this domain within the current genomic landscape. results: we carried out sensitive and exhaustive psi-blast ... | 2005 | 16306392 |
| kinetic and thermodynamic analysis of bradyrhizobium japonicum puta-membrane associations. | in escherichia coli, proline induces tight membrane binding of the puta flavoenzyme and transforms puta from a transcriptional repressor to a membrane-associated proline catabolic enzyme. in other gram-negative bacteria such as bradyrhizobium japonicum, puta lacks dna binding activity and functions only as a proline catabolic enzyme. here, we characterize the membrane binding properties of puta from b. japonicum (bjputa) to address whether proline regulates bjputa-lipid binding similar to escher ... | 2006 | 16310755 |
| design and validation of a partial-genome microarray for transcriptional profiling of the bradyrhizobium japonicum symbiotic gene region. | the design and use of a pilot microarray for transcriptome analysis of the symbiotic, nitrogen-fixing bradyrhizobium japonicum is reported here. the custom-synthesized chip (affymetrix genechip) features 738 genes, more than half of which belong to a 400-kb chromosomal segment strongly associated with symbiosis-related functions. rna was isolated following an optimized protocol from wild-type cells grown aerobically and microaerobically, and from cells of aerobically grown regr mutant and microa ... | 2006 | 16328374 |
| microarray-based detection and typing of the rhizobium nodulation gene nodc: potential of dna arrays to diagnose biological functions of interest. | environmental screening of bacteria for the presence of genes of interest is a challenging problem, due to the high variability of the nucleotide sequence of a given gene between species. here, we tackle this general issue using a particularly well-suited model system that consists of the nodulation gene nodc, which is shared by phylogenetically distant rhizobia. 41mer and 50mer oligonucleotides featuring the nucleotide diversity of two highly conserved regions of the nodc protein were spotted o ... | 2005 | 16332784 |
| influence of inorganic nitrogen management regime on the diversity of nitrite-oxidizing bacteria in agricultural grassland soils. | to assess links between the diversity of nitrite-oxidizing bacteria (nob) in agricultural grassland soils and inorganic n fertilizer management, nob communities in fertilized and unfertilized soils were characterized by analysis of clone libraries and denaturing gradient gel electrophoresis (dgge) of 16s rrna gene fragments. previously uncharacterized nitrospira-like sequences were isolated from both long-term-fertilized and unfertilized soils, but dgge migration patterns indicated the presence ... | 2005 | 16332819 |
| activity and composition of the denitrifying bacterial community respond differently to long-term fertilization. | the objective of this study was to explore the long-term effects of different organic and inorganic fertilizers on activity and composition of the denitrifying and total bacterial communities in arable soil. soil from the following six treatments was analyzed in an experimental field site established in 1956: cattle manure, sewage sludge, ca(no3)2, (nh4)2so4, and unfertilized and unfertilized bare fallow. all plots but the fallow were planted with corn. the activity was measured in terms of pote ... | 2005 | 16332820 |
| diversity and structure of bacterial chemolithotrophic communities in pine forest and agroecosystem soils. | obligate lithotrophs (e.g., ammonia oxidizers) and facultative lithotrophs (e.g., co and hydrogen oxidizers) collectively comprise a phylogenetically diverse functional group that contributes significantly to carbon and nitrogen cycles in soils and plays important roles in trace gas dynamics (e.g., carbon monoxide and nitrous and nitric oxides) that affect tropospheric chemistry and radiative forcing. in spite of their diverse physiologies, facultative and obligate lithotrophs typically possess ... | 2005 | 16332829 |
| comparative genomic analyses of the bacterial phosphotransferase system. | we report analyses of 202 fully sequenced genomes for homologues of known protein constituents of the bacterial phosphoenolpyruvate-dependent phosphotransferase system (pts). these included 174 bacterial, 19 archaeal, and 9 eukaryotic genomes. homologues of pts proteins were not identified in archaea or eukaryotes, showing that the horizontal transfer of genes encoding pts proteins has not occurred between the three domains of life. of the 174 bacterial genomes (136 bacterial species) analyzed, ... | 2005 | 16339738 |
| the manganese-responsive repressor mur of rhizobium leguminosarum is a member of the fur-superfamily that recognizes an unusual operator sequence. | the manganese uptake regulator mur of rhizobium leguminosarum is a close homologue of the global iron regulatory protein fur. mur represses the sitabcd operon, which encodes a mn2+ transport system, specifically in response to mn2+ but not fe2+. in previous work the authors mapped the 5' ends of two sit operon transcripts, termed ts1 and ts2, which were co-ordinately regulated by mn2+-mur, but this paper now shows that only ts1 is a primary transcript. dnase i protection analyses showed that pur ... | 2005 | 16339952 |
| mutational analysis of the c-terminal domain of the rhodobacter sphaeroides response regulator prra. | the rhodobacter sphaeroides response regulator prra directly activates transcription of genes necessary for energy conservation at low o2 tensions and under anaerobic conditions. it is proposed that prra homologues contain a c-terminal dna-binding domain (prra-ctd) that lacks significant amino acid sequence similarity to those found in other response regulators. to test this hypothesis, single amino acid substitutions were created at 12 residues in the prra-ctd. these mutant prra proteins were p ... | 2005 | 16339955 |
| persistence of rhizobium japonicum on the soybean seed coat under controlled temperature and humidity. | when rhizobium japonicum strain 61a68 was added to surface-sterilized soybean (glycine max) seed along with 12 different coating materials, a definite effect of temperature upon survival was observed both with and without coating materials. at a storage temperature of 15 degrees c and 50 +/- 5% relative humidity, from 0.9 to 14.1% of the original inoculum survived for 3 weeks. at 22.5 degrees c, from 0.5 to 7.2% of the original inoculum survived. at 30 degrees c, from 0.1 to 1.6% of the original ... | 1978 | 16345264 |
| hydrogen evolution from alfalfa and clover nodules and hydrogen uptake by free-living rhizobium meliloti. | a series of rhizobium meliloti and rhizobium trifolii strains were used as inocula for alfalfa and clover, respectively, grown under bacteriologically controlled conditions. replicate samples of nodules formed by each strain were assayed for rates of h(2) evolution in air, rates of h(2) evolution under ar and o(2), and rates of c(2)h(2) reduction. nodules formed by all strains of r. meliloti and r. trifolii on their respective hosts lost at least 17% of the electron flow through nitrogenase as e ... | 1979 | 16345361 |
| polyacrylamide-entrapped rhizobium as an inoculant for legumes. | pot experiments showed that rhizobium japonicum cells entrapped in a polyacrylamide gel could be used as an inoculant for soybeans and compared favorably to laboratory-made peat base inoculant containing the same bacterial strain. | 1979 | 16345370 |
| population densities of rhizobium japonicum strain 123 estimated directly in soil and rhizospheres. | rhizobium japonicum serotype 123 was enumerated in soil and rhizospheres by fluorescent antibody techniques. counting efficiency was estimated to be about 30%. indigenous populations of strain 123 ranged from a few hundred to a few thousand per gram of field soil before planting. rhizosphere effects from field-grown soybean plants were modest, reaching a maximum of about 2 x 10 cells of strain 123 per g of inner rhizosphere soil in young (16-day-old) plants. comparably slight rhizosphere stimula ... | 1979 | 16345383 |
| modified fluorescent technique, using rhodamine, for studies of rhizobium japonicum-soybean symbiosis. | rhodamine-conjugated capsular polysaccharides isolated from rhizobium japonicum 61a76ns were used to examine binding between the labeled polysaccharides and soybean roots. fluorescein-labeled polysaccharides were not satisfactory because soybean root hairs autofluoresce in the fluorescein region. | 1979 | 16345405 |
| binding characteristics of n(2)-fixing bacteria to cereal roots. | the attachment of rhizobium japonicum 61a89 and rhizobium spp. 32h1 to the roots of wheat and rice seedlings is analyzed in terms of an equilibrium model. a langmuir adsorption isotherm describes the binding. strain 61a89 binds to a greater extent than does strain 32h1, and the equilibrium constants for each strain binding to wheat are strongly temperature dependent. both time-dependent dissociation and association, predicted by an equilibrium model, have been found. the dissociation rate consta ... | 1979 | 16345433 |
| use of two-dimensional polyacrylamide electrophoresis to demonstrate that putative rhizobium cross-inoculation mutants actually are contaminants. | two-dimensional polyacrylamide electrophoresis was used to determine that mutants of rhizobium trifolii dt6, claimed to be capable of effectively nodulating soybeans, were actually rhizobium japonicum 110 contaminants isolated from the parent dt6 culture. | 1980 | 16345520 |
| density centrifugation method for recovering rhizobium spp. from soil for fluorescent-antibody studies. | a density centrifugation procedure has been developed as a replacement for soil flocculation and clarification steps employed in quantitative fluorescent-antibody studies on rhizobium in soils. near-quantitative recovery of added cells of two strains of rhizobium japonicum and two strains of r. phaseoli was achieved from six soils with various properties. it is proposed that this technique may prove useful in separating other soil microorganisms from soil particles in ecological studies employin ... | 1980 | 16345522 |
| accumulation of soybean lectin-binding polysaccharide during growth of rhizobium japonicum as determined by hemagglutination inhibition assay. | a hemagglutination inhibition assay was used to estimate the presence of soybean lectin-binding polysaccharide in whole culture, culture supernatant, and isolated exopolysaccharide of rhizobium japonicum usda 138. the occurrence of 0.1 to 0.2 mug of lectin-binding polysaccharide could be detected within 2 h with a 0.5-ml total sample. lectin-binding polysaccharide was detected in all preparations during both exponential and stationary growth phases. the formation of lectin-binding polysaccharide ... | 1980 | 16345578 |
| diversity and dynamics of indigenous rhizobium japonicum populations. | a simple method, based upon the separation of cellular proteins by sodium dodecyl sulfate (sds)-polyacrylamide gel electrophoresis, has been devised for distinguishing between isolates of rhizobium japonicum. eleven laboratory strains, previously classified into five serogroups, were analyzed by gel electrophoresis. groups determined subjectively according to protein patterns matched the serogroups, with one exception. most strains within serogroups could be distinguished from one another. for s ... | 1980 | 16345658 |
| growth of rhizobium japonicum strains at temperatures above 27 degrees c. | a study was conducted to examine the growth responses of different rhizobium japonicum strains to increasing temperatures, determine the degree of variability among strains in those responses, and identify temperature-related growth characteristics that could be used to select temperature-tolerant strains. each of 42 strains was grown in liquid culture for 96 h at 19 incubation temperatures ranging from 27.4 to 54.1 degrees c in a temperature gradient apparatus. growth was estimated by measuring ... | 1981 | 16345827 |
| dilution of liquid rhizobium cultures to increase production capacity of inoculant plants. | experiments were undertaken to test whether peat-based legume seed inoculants, which are prepared with liquid cultures that have been deliberately diluted, can attain and sustain acceptable numbers of viable rhizobia. liquid cultures of rhizobium japonicum and rhizobium phaseoli were diluted to give 10, 10, or 10 cells per ml, using either deionized water, quarter-strength yeast-mannitol broth, yeast-sucrose broth, or yeast-water. the variously diluted cultures were incorporated into gamma-irrad ... | 1982 | 16346075 |
| variations in ability of rhizobium japonicum strains to nodulate soybeans and maintain fixation in the presence of nitrate. | this study investigated differences in sensitivity to nitrate of soybean (glycine max cv. davis) symbioses with 16 different rhizobium japonicum strains. when nitrate (20 mm) was added to established symbioses, there were no significant differences in the degree of inhibition of acetylene reduction for any of the 16 strains. when nitrate was present during the establishment of nodules, high levels of nitrate (10 mm) were equally inhibitory on all symbioses, whereas specific strain effects appear ... | 1982 | 16346093 |
| rapid colony screening method for identifying hydrogenase activity in rhizobium japonicum. | a method has been developed for the rapid screening of rhizobium japonicum colonies for hydrogenase activity based on their ability to reduce methylene blue in the presence of respiratory inhibitors and hydrogen. hydrogen uptake-positive (hup) colonies derepressed for hydrogenase activity were visualized by their localized decolorization of filter paper disks impregnated with the dye. appropriate responses were seen with a number of hup and hup wild-type strains of r. japonicum as well as hup mu ... | 1983 | 16346252 |
| physiology of ex planta nitrogenase activity in rhizobium japonicum. | thirty-nine wild-type strains of rhizobium japonicum have been studied for their ability to synthesize nitrogenase ex planta in defined liquid media under microaerobic conditions. twenty-one produced more than trace amounts of acetylene reduction activity, but only a few of these yielded high activity. the oxygen response curves were similar for most of the nitrogenase-positive strains. the strains derepressible for activity had several phenotypic characteristics different from non-derepressible ... | 1983 | 16346295 |
| evaluation of nitrate reductase activity in rhizobium japonicum. | nitrate reductase activity was evaluated by four approaches, using four strains of rhizobium japonicum and 11 chlorate-resistant mutants of the four strains. it was concluded that in vitro assays with bacteria or bacteroids provide the most simple and reliable assessment of the presence or absence of nitrate reductase. nitrite reductase activity with methyl viologen and dithionite was found, but the enzyme activity does not confound the assay of nitrate reductase. | 1983 | 16346376 |