| isolation and characterization of the major nod factor of bradyrhizobium japonicum strain 532c. | bradyrhizobium japonicum 532c nodulates soybean effectively under cool canadian spring conditions and is used in canadian commercial inoculants. the major lipo-chitooligosaccharide (lco), bacteria-to-plant signal was characterized by hplc, fab-mass spectroscopy maldi-tof mass spectroscopy and revealed to be lco nod bj-v (c18:1, mefuc). this lco is produced by type i strains of b. japonicum and is therefore unlikely to account for this strains superior ability to nodulate soybean under canadian c ... | 2002 | 11911611 |
| enterococcus faecalis acetoacetyl-coenzyme a thiolase/3-hydroxy-3-methylglutaryl-coenzyme a reductase, a dual-function protein of isopentenyl diphosphate biosynthesis. | many bacteria employ the nonmevalonate pathway for synthesis of isopentenyl diphosphate, the monomer unit for isoprenoid biosynthesis. however, gram-positive cocci exclusively use the mevalonate pathway, which is essential for their growth (e. i. wilding et al., j. bacteriol. 182:4319-4327, 2000). enzymes of the mevalonate pathway are thus potential targets for drug intervention. uniquely, the enterococci possess a single open reading frame, mvae, that appears to encode two enzymes of the mevalo ... | 2002 | 11914342 |
| analysis of bacteria contaminating ultrapure water in industrial systems. | bacterial populations inhabiting ultrapure water (upw) systems were investigated. the analyzed upw systems included pilot scale, bench scale, and full size upw plants employed in the semiconductor and other industries. bacteria present in the polishing loop of the upw systems were enumerated by both plate counts and epifluorescence microscopy. assessment of bacterial presence in upw by epifluorescence microscopy (cyanotolyl tetrazolium chloride [ctc] and dapi [4',6'-diamidino-2-phenylindole] sta ... | 2002 | 11916667 |
| bradyrhizobia from wild phaseolus, desmodium, and macroptilium species in northern mexico. | rrna genetic markers were analyzed in 97 isolates of nodule bacteria from six legume species in chihuahua, mexico. the most common genotypes were widely shared across host species and had 16s rrna sequences identical to those of strains from an eastern north american legume (amphicarpaea) that are closely related to bradyrhizobium elkanii. | 2002 | 11916730 |
| a comparative resonance raman analysis of heme-binding pas domains: heme iron coordination structures of the bjfixl, axpdea1, ecdos, and mtdos proteins. | the heme-pas is a specialized domain with which a broad class of signal-transducing heme proteins detect physiological heme ligands. such domains exhibit a wide range of ligand binding parameters, yet they are all expected to feature an alpha-beta heme binding fold and a predominantly hydrophobic heme distal pocket without a distal histidine. we have compared, for the first time, the resonance raman spectra of several heme-pass: the heme-binding domains of bradyrhizobium japonicum fixl, escheric ... | 2002 | 11939776 |
| mutations in flavobacterium johnsoniae gldf and gldg disrupt gliding motility and interfere with membrane localization of glda. | flavobacterium johnsoniae moves rapidly over surfaces by a process known as gliding motility. the mechanism of this form of motility is not known. four genes that are required for f. johnsoniae gliding motility, glda, gldb, gldd, and ftsx, have recently been described. glda is similar to the atp-hydrolyzing components of atp binding cassette (abc) transporters. tn4351 mutagenesis was used to identify two additional genes, gldf and gldg, that are required for cell movement. gldf and gldg appear t ... | 2002 | 11948149 |
| spatial distribution of total, ammonia-oxidizing, and denitrifying bacteria in biological wastewater treatment reactors for bioregenerative life support. | bioregenerative life support systems may be necessary for long-term space missions due to the high cost of lifting supplies and equipment into orbit. in this study, we investigated two biological wastewater treatment reactors designed to recover potable water for a spacefaring crew being tested at johnson space center. the experiment (lunar-mars life support test project-phase iii) consisted of four crew members confined in a test chamber for 91 days. in order to recycle all water during the exp ... | 2002 | 11976099 |
| engineering the rhizobium leguminosarum bv. viciae hydrogenase system for expression in free-living microaerobic cells and increased symbiotic hydrogenase activity. | rhizobium leguminosarum bv. viciae upm791 induces hydrogenase activity in pea (pisum sativum l.) bacteroids but not in free-living cells. the symbiotic induction of hydrogenase structural genes (hupsl) is mediated by nifa, the general regulator of the nitrogen fixation process. so far, no culture conditions have been found to induce nifa-dependent promoters in vegetative cells of this bacterium. this hampers the study of the r. leguminosarum hydrogenase system. we have replaced the native nifa-d ... | 2002 | 11976122 |
| isolation of plant-growth-promoting bacillus strains from soybean root nodules. | endophytic bacteria reside within plant tissues and have often been found to promote plant growth. fourteen strains of putative endophytic bacteria, not including endosymbiotic bradyrhizobium strains, were isolated from surface-sterilized soybean (glycine max. (l.) merr.) root nodules. these isolates were designated as non-bradyrhizobium endophytic bacteria (neb). three isolates (neb4, neb5, and neb17) were found to increase soybean weight when plants were co-inoculated with one of the isolates ... | 2002 | 11989767 |
| biochemical, molecular, and genetic analyses of the acetone carboxylases from xanthobacter autotrophicus strain py2 and rhodobacter capsulatus strain b10. | acetone carboxylase is the key enzyme of bacterial acetone metabolism, catalyzing the condensation of acetone and co(2) to form acetoacetate. in this study, the acetone carboxylase of the purple nonsulfur photosynthetic bacterium rhodobacter capsulatus was purified to homogeneity and compared to that of xanthobacter autotrophicus strain py2, the only other organism from which an acetone carboxylase has been purified. the biochemical properties of the enzymes were virtually indistinguishable, wit ... | 2002 | 12003937 |
| comparative sequence analysis of the symbiosis island of mesorhizobium loti strain r7a. | the mesorhizobium loti strain r7a symbiosis island is a 502-kb chromosomally integrated element which transfers to nonsymbiotic mesorhizobia in the environment, converting them to lotus symbionts. it integrates into a phenylalanine trna gene in a process mediated by a p4-type integrase encoded at the left end of the element. we have determined the nucleotide sequence of the island and compared its deduced genetic complement with that reported for the 611-kb putative symbiosis island of m. loti s ... | 2002 | 12003951 |
| rhizobial position as a main determinant in the problem of competition for nodulation in soybean. | selected bradyrhizobium japonicum strains inoculated on soybean seeds often fail to occupy a significant proportion of nodules when a competitor rhizobial population is established in the soil. this competition problem could result from a genetic/ physiological advantage of the adapted soil population over the introduced inoculant or from a positional advantage, as the soil population already occupies the soil profile where the roots will penetrate, whereas the inoculant remains concentrated aro ... | 2002 | 12010128 |
| the highly conserved tldd and tlde proteins of escherichia coli are involved in microcin b17 processing and in ccda degradation. | microcin b17 (mccb17) is a peptide antibiotic produced by escherichia coli strains carrying the pmccb17 plasmid. mccb17 is synthesized as a precursor containing an amino-terminal leader peptide that is cleaved during maturation. maturation requires the product of the chromosomal tlde (pmba) gene. mature microcin is exported across the cytoplasmic membrane by a dedicated abc transporter. in sensitive cells, mccb17 targets the essential topoisomerase ii dna gyrase. independently, tlde as well as t ... | 2002 | 12029038 |
| structure of malonamidase e2 reveals a novel ser-cisser-lys catalytic triad in a new serine hydrolase fold that is prevalent in nature. | a large group of hydrolytic enzymes, which contain a conserved stretch of approximately 130 amino acids designated the amidase signature (as) sequence, constitutes a super family that is distinct from any other known hydrolase family. as family enzymes are widespread in nature, ranging from bacteria to humans, and exhibit a variety of biological functions. here we report the first structure of an as family enzyme provided by the crystal structure of malonamidase e2 from bradyrhizobium japonicum. ... | 2002 | 12032064 |
| key role of bacterial nh(4)(+) metabolism in rhizobium-plant symbiosis. | symbiotic nitrogen fixation is carried out in specialized organs, the nodules, whose formation is induced on leguminous host plants by bacteria belonging to the family rhizobiaceae: nodule development is a complex multistep process, which requires continued interaction between the two partners and thus the exchange of different signals and metabolites. nh(4)(+) is not only the primary product but also the main regulator of the symbiosis: either as ammonium and after conversion into organic compo ... | 2002 | 12040124 |
| lateral gene transfer and parallel evolution in the history of glutathione biosynthesis genes. | glutathione is found primarily in eukaryotes and in gram-negative bacteria. it has been proposed that eukaryotes acquired the genes for glutathione biosynthesis from the alpha-proteobacterial progenitor of mitochondria. to evaluate this, we have used bioinformatics to analyze sequences of the biosynthetic enzymes gamma-glutamylcysteine ligase and glutathione synthetase. | 2002 | 12049666 |
| evolutionary relationship of phototrophic bacteria in the alpha-proteobacteria based on farnesyl diphosphate synthase. | partial sequences of farnesyl diphosphate (fpp) synthase genes derived from the rhodobacter-rhodovulum group and from the rhodopseudomonas palustris-bradyrhizobium japonicum group of the alpha-proteobacteria were subjected to phylogenetic analysis to investigate the relationships of phototrophic and non-phototrophic bacteria in the alpha-proteobacteria . the four rhodovulum species formed a monophyletic group within the rhodobacter cluster, and agrobacterium ferrugineum iam 12616(t) intermingled ... | 2002 | 12055311 |
| identification of two quorum-sensing systems in sinorhizobium meliloti. | sinorhizobium meliloti is a free-living soil bacterium which is capable of establishing a symbiotic relationship with the alfalfa plant (medicago sativa). this symbiosis involves a network of bacterium-host signaling, as well as the potential for bacterium-bacterium communication, such as quorum sensing. in this study, we characterized the production of n-acyl homoserine lactones (ahls) by two commonly used s. meliloti strains, ak631 and rm1021. we found that ak631 produces at least nine differe ... | 2002 | 12057940 |
| involvement of the prrb/prra two-component system in nitrite respiration in rhodobacter sphaeroides 2.4.3: evidence for transcriptional regulation. | rhodobacter sphaeroides strain 2.4.3 is capable of diverse metabolic lifestyles, including denitrification. the regulation of many rhodobacter genes involved in redox processes is controlled, in part, by the prrba two-component sensor-regulator system, where prrb serves as the sensor kinase and prra is the response regulator. four strains of 2.4.3 carrying mutations within the prrb gene were isolated in a screen for mutants unable to grow anaerobically on medium containing nitrite. studies revea ... | 2002 | 12057946 |
| the rhizobium etli cyac product: characterization of a novel adenylate cyclase class. | adenylate cyclases (acs) catalyze the formation of 3',5'-cyclic amp (camp) from atp. a novel ac-encoding gene, cyac, was isolated from rhizobium etli by phenotypic complementation of an escherichia coli cya mutant. the functionality of the cyac gene was corroborated by its ability to restore camp accumulation in an e. coli cya mutant. further, overexpression of a male::cyac fusion protein allowed the detection of significant ac activity levels in cell extracts of an e. coli cya mutant. cyac is u ... | 2002 | 12057950 |
| substrate specificity of nickel/cobalt permeases: insights from mutants altered in transmembrane domains i and ii. | hoxn, a high-affinity, nickel-specific permease of ralstonia eutropha h16, and nhlf, a nickel/cobalt permease of rhodococcus rhodochrous j1, are structurally related members of the nickel/cobalt transporter (nicot) family. these transporters have an eight-helix structure and are characterized by highly conserved segments with polar or charged amino acid residues in transmembrane domains (tmds) ii, iii, v, and vi. two histidine residues in a ni2+ binding motif, the signature sequence of nicots, i ... | 2002 | 12057951 |
| the biosynthetic gene cluster of the maytansinoid antitumor agent ansamitocin from actinosynnema pretiosum. | maytansinoids are potent antitumor agents found in plants and microorganisms. to elucidate their biosynthesis at the biochemical and genetic level and to set the stage for their structure modification through genetic engineering, we have cloned two gene clusters required for the biosynthesis of the maytansinoid, ansamitocin, from a cosmid library of actinosynnema pretiosum ssp. auranticum atcc 31565. this is a rare case in which the genes involved in the formation of a secondary metabolite are d ... | 2002 | 12060743 |
| a salmonella enterica serovar typhimurium hema mutant is highly susceptible to oxidative dna damage. | the first committed step in the biosynthesis of heme, an important cofactor of two catalases and a number of cytochromes, is catalyzed by the hema gene product. salmonella enterica serovar typhimurium hema26::tn10d (hema26) was identified in a genetic screen of insertion mutants that were sensitive to hydrogen peroxide. here we show that the hema26 mutant respires at half the rate of wild-type cells and is highly susceptible to the effects of oxygen species. exposure of the hema26 strain to hydr ... | 2002 | 12081946 |
| novel dna-binding proteins in the cyanobacterium anabaena sp. strain pcc 7120. | as an approach towards elucidation of the biochemical regulation of the progression of heterocyst differentiation in anabaena sp. strain pcc 7120, we have identified proteins that bind to a 150-bp sequence upstream from hepc, a gene that plays a role in the synthesis of heterocyst envelope polysaccharide. such proteins were purified in four steps from extracts of vegetative cells of anabaena sp. two of these proteins (abp1 and abp2) are encoded by neighboring genes in the anabaena sp. chromosome ... | 2002 | 12081965 |
| cloning and characterization of the phosphatidylserine synthase gene of agrobacterium sp. strain atcc 31749 and effect of its inactivation on production of high-molecular-mass (1-->3)-beta-d-glucan (curdlan). | genes involved in the production of the extracellular (1-->3)-beta-glucan, curdlan, by agrobacterium sp. strain atcc 31749 were described previously (stasinopoulos et al., glycobiology 9:31-41, 1999). to identify additional curdlan-related genes whose protein products occur in the cell envelope, the transposon tnphoa was used as a specific genetic probe. one mutant was unable to produce high-molecular-mass curdlan when a previously uncharacterized gene, pss(ag), encoding a 30-kda, membrane-assoc ... | 2002 | 12107128 |
| sinorhizobium fredii isolates can be specifically identified by a 260 bp fragment from the nolxwbtuv locus. | a pair of primers homologous to the nolxwbtuv locus generated a 260 bp fragment by pcr only in the presence of sinorhizobium fredii template dna of different quality. this resulted in a fast and accurate method for the identification of s. fredii either from pure dna, whole bacterial cells or nodule extracts. by means of two pcr fragments, one specific for s. fredii (260-bp) and the other specific for bradyrhizobium japonicum (rsalpha), we found that s. fredii strain smh12 and b. japonicum e109 ... | 2002 | 12111156 |
| the soybean gmn6l gene encodes a late nodulin expressed in the infected zone of nitrogen-fixing nodules. | previously, we determined the n-terminal amino acid sequences of a number of putative peribacteroid membrane proteins from soybean. here, we report the cloning of a gene, gmn6l, that encodes one of these proteins. the protein encoded by gmn6l is similar in sequence to mtn6, an early nodulin expressed in medicago truncatula roots in response to infection by sinorhizobium meliloti. the gmn6l gene was strongly expressed in mature nodules but not in other plant organs. gmn6l protein was first detect ... | 2002 | 12118878 |
| a critical motif for oligomerization and chaperone activity of bacterial alpha-heat shock proteins. | oligomerization into multimeric complexes is a prerequisite for the chaperone function of almost all alpha-crystallin type heat shock proteins (alpha-hsp), but the molecular details of complex assembly are poorly understood. the alpha-hsp proteins from bradyrhizobium japonicum are suitable bacterial models for structure-function studies of these ubiquitous stress proteins. they fall into two distinct classes, a and b, display chaperone activity in vitro and form oligomers of approximately 24 sub ... | 2002 | 12135498 |
| biodiversity of denitrifying and dinitrogen-fixing bacteria in an acid forest soil. | isolated soil dna from an oak-hornbeam forest close to cologne, germany, was suitable for pcr amplification of gene segments coding for the 16s rrna and nitrogenase reductase (nifh), nitrous oxide reductase (nosz), cytochrome cd(1)-containing nitrite reductase (nirs), and cu-containing nitrite reductase (nirk) of denitrification. for each gene segment, diverse pcr products were characterized by cloning and sequencing. none of the 16s rrna gene sequences was identical to any deposited in the data ... | 2002 | 12147477 |
| the diversity of phaseolus-nodulating rhizobial populations is altered by liming of acid soils planted with phaseolus vulgaris l. in brazil. | pcr-mediated restriction fragment length polymorphism (rflp) analysis of the 16s-23s rrna internally transcribed spacer (its) region and the 16s rrna gene indicated that the rhizobial populations isolated from common bean (phaseolus vulgaris l.) nodules in the unlimed soil from a series of five lime rates applied 6 years previously to plots of an acidic oxisol had less diversity than those from plots with higher rates of liming. isolates affiliated with rhizobium tropici iib and rhizobium legumi ... | 2002 | 12147504 |
| pseudomonas aeruginosa synthesizes phosphatidylcholine by use of the phosphatidylcholine synthase pathway. | phosphatidylcholine (pc) is a ubiquitous membrane lipid in eukaryotes but has been found in only a limited number of prokaryotes. both eukaryotes and prokaryotes synthesize pc by methylating phosphatidylethanolamine (pe) by use of a phospholipid methyltransferase (pmt). eukaryotes can synthesize pc by the activation of choline to form choline phosphate and then cdp-choline. the cdp-choline then condenses with diacylglycerol (dag) to form pc. in contrast, prokaryotes condense choline directly wit ... | 2002 | 12169604 |
| the major nod factor of bradyrhizobium japonicum promotes early growth of soybean and corn. | greenhouse experiments were conducted to evaluate the effect of nod factor nod bj-v (c18:1, mefuc) of badyrhizobium japonicum on the growth of soybean and corn. three-day-old seedlings of soybean and corn were grown in hydroponic solutions containing four concentrations (0, 10(-7), 10(-9) or 10(-11) m) of nod factor. after 7 d of treatment, nod factor enhanced soybean and corn biomass. nod factor elicited profound effects on root growth resulting in 34-44% longer roots in soybean. more detailed ... | 2002 | 12177132 |
| conflicting phylogeographic patterns in rrna and nifd indicate regionally restricted gene transfer in bradyrhizobium. | major differences in evolutionary relationships of the 16s rrna gene and the nitrogenase alpha-subunit gene (nifd) were observed among 38 strains of bradyrhizobium sp. nodule bacteria from north america, central america, asia and australia. two lineages were evident in the 16s rrna phylogeny representing strains related to bradyrhizobium japonicum (29 isolates) or bradyrhizobium elkanii (9 isolates). both clades were distributed across most or all of the geographic regions sampled. by contrast, ... | 2002 | 12177349 |
| identification of a soybean protein that interacts with gaga element dinucleotide repeat dna. | dinucleotide repeat dna with the pattern (ga)(n)/(tc)(n), so-called gaga elements, control gene expression in animals, and are recognized by a specific regulatory protein. here, a yeast one-hybrid screen was used to isolate soybean (glycine max) cdna encoding a gaga-binding protein (gbp) that binds to (ga)(n)/(ct)(n) dna. soybean gbp was dissimilar from the gaga factor of drosophila melanogaster. recombinant gbp protein did not bind to dinucleotide repeat sequences other than (ga)(n)/(ct)(n). gb ... | 2002 | 12177492 |
| a novel two-component system of bradyrhizobium japonicum: elms and elmr are encoded in diverse orientations. | by completely sequencing the bradyrhizobium japonicum insert of cosmid c27, a pair of genes was identified which was found to be highly similar to prokaryotic two-component systems. the genes of the putative regulator protein (214 aa), elmr, and the putative sensor histidine kinase (470 aa), elms, are divergently oriented with their putative translational start sites separated by only 85 nucleotides. this new locus is located about 10 kb upstream of the sips signal peptidase allele. the highest ... | 2002 | 12180351 |
| mycobacterium smegmatis l-alanine dehydrogenase (ald) is required for proficient utilization of alanine as a sole nitrogen source and sustained anaerobic growth. | nad(h)-dependent l-alanine dehydrogenase (ec 1.4.1.1) (ald) catalyzes the oxidative deamination of l-alanine and the reductive amination of pyruvate. to assess the physiological role of ald in mycobacterium smegmatis, we cloned the ald gene, identified its promoter, determined the protein expression levels, and analyzed the combined effects of nutrient supplementation, oxygen availability, and growth stage on enzyme activity. high ald activities were observed in cells grown in the presence of l- ... | 2002 | 12193615 |
| the formation of nitrogen-fixing bacteroids is delayed but not abolished in soybean infected by an [alpha]-ketoglutarate dehydrogenase-deficient mutant of bradyrhizobium japonicum. | a mutant strain of bradyrhizobium japonicum usda 110 devoid of [alpha]-ketoglutarate dehydrogenase activity (lsg184) was used to test whether this tricarboxylic acid cycle enzyme is necessary to support nitrogen fixation during symbiosis with soybean (glycine max). lsg184 formed nodules about 5 d later than the wild-type strain, and the nodules, although otherwise normal in structure, contained many fewer infected host cells than is typical. at 19 d after inoculation cells infected with the muta ... | 1997 | 12223774 |
| total glutamine synthetase activity during soybean nodule development is controlled at the level of transcription and holoprotein turnover. | gln synthetase (gs) catalyzes the atp-dependent condensation of ammonia with glutamate to yield gln. in higher plants gs is an octameric enzyme and the subunits are encoded by members of a small multigene family. in soybeans (glycine max), following the onset of n2 fixation there is a dramatic increase in gs activity in the root nodules. gs activity staining of native polyacrylamide gels containing nodule and root extracts showed a common band of activity (gsrs). the nodules also contained a slo ... | 1996 | 12226474 |
| fate of nodule-specific polysaccharide produced by bradyrhizobium japonicum bacteroids. | a polysaccharide produced by bradyrhizobium japonicum bacteroids in nodules (nps) on soybean (glycine max [l.] merr.) roots is different in composition and structure from the extracellular polysaccharide produced in culture by this organism. isogenic strains either capable or incapable of nps synthesis supported similar rates of plant growth and nitrogenase activity, indicating that polysaccharide deposition was not detrimental. the possibility that nps may have some protective or nutritional ro ... | 1995 | 12228408 |
| preincubation of bradyrhizobium japonicum with genistein accelerates nodule development of soybean at suboptimal root zone temperatures. | in the soybean (glycine max [l.] merr.) n2-fixing symbiosis, suboptimal root zone temperatures (rzts) slow nodule development, especially at temperatures below 17[deg]c. a step in the infection process that occurs within the first 24 h is particularly sensitive to suboptimal rzt. the first phase in the establishment of the soybean-bradyrhizobium japonicum symbiosis is the exchange of recognition molecules. the most effective plant-to-bacterium signal is genistein. binding of genistein to b. japo ... | 1995 | 12228519 |
| rhizobial nodulation factors stimulate mycorrhizal colonization of nodulating and nonnodulating soybeans. | legumes form tripartite symbiotic associations with noduleinducing rhizobia and vesicular-arbuscular mycorrhizal fungi. co-inoculation of soybean (glycine max [l.] merr.) roots with bradyrhizobium japonicum 61-a-101 considerably enhanced colonization by the mycorrhizal fungus glomus mosseae. a similar stimulatory effect on mycorrhizal colonization was also observed in nonnodulating soybean mutants when inoculated with bradyrhizobium japonicum and in wild-type soybean plants when inoculated with ... | 1995 | 12228558 |
| the rhizobial hema gene is required for symbiosis in species with deficient [delta]-aminolevulinic acid uptake activity. | most rhizobial hema mutants induce root nodules on their respective legume hosts that lack nitrogen fixation activity and leghemoglobin expression. however, a bradyrhizobium japonicum hema mutant elicits effective nodules on soybean, and we proposed previously that synthesis and uptake of the heme precursor [delta]-aminolevulinic acid (ala) by the plant and bacterial symbiont, respectively, allow mutant rescue (i. sangwan, m.r. o'brian [1991] science 251: 1220-1222). in the present work, the b. ... | 1995 | 12228561 |
| cyclic [beta]-1,6 -1,3 glucans are synthesized by bradyrhizobium japonicum bacteroids within soybean (glycine max) root nodules. | we have previously reported that free-living cultures of bradyrhizobium species produce novel oligosaccharides that are cyclic, contain between 10 and 13 glucose residues, and are linked by [beta]-1,6 and [beta]-1,3 glycosidic bonds (k.j. miller, r.s. gore, r. johnson, a.j. benesi, v.n. reinhold [1990] j bacteriol 172: 136-142). in the present study, we show that these glucans are also synthesized by bacteroids of bradyrhizobium japonicum usda 110 within glycine max root nodules. | 1993 | 12231809 |
| kinetics of nodule development in glycine soja. | nodule development in the interaction of glycine soja sieb. & zucc. pi468.397 with bradyrhizobium japonicum usda110 was studied by hypochlorite clearing and methylene blue staining. even the earliest stages of nodule development could be observed. the entire length of the primary root was examined up to 15 d postinoculation. markedly curled root hairs and the first cell divisions in the hypodermal layer (stage i) were observed 2 d postinoculation, and by 3 d cell division activity had spread to ... | 1993 | 12232007 |
| composition and distribution of adenylates in soybean (glycine max l.) nodule tissue. | adenylates (atp, adp, and amp) may play a central role in the regulation of the o2-limited c and n metabolism of soybean nodules. to be able to interpret measurements of adenylate levels in whole nodules and to appreciate the significance of observed changes in adenylates associated with changes in o2-limited metabolism, methods were developed for measuring in vivo levels of adenylate pools in the cortex, plant central zone, and bacteroid fractions of soybean (glycine max l. merr cv maple arrow ... | 1994 | 12232074 |
| cyclic [beta]-1,6-1,3-glucans of bradyrhizobium japonicum usda 110 elicit isoflavonoid production in the soybean (glycine max) host. | high levels of cyclic [beta]-1,6-1,3-glucans (e.g. 0.1 mg mg-1 of total protein) are synthesized by free-living cells as well as by bacteroids of bradyrhizobium japonicum usda 110 (k.j. miller, r.s. gore, r. johnson, a.j. benesi, v.n. reinhold [1990] j bacteriol 172: 136-142; r.s. gore and k.j. miller [1993] plant physiol 102: 191-194). these molecules share structural features with glucan fragments isolated from the mycelial cell wall of the soybean (glycine max) pathogen phytophthora megasperm ... | 1994 | 12232136 |
| diversity among bradyrhizobium isolates nodulating yardlong bean and sunnhemp in guam. | to isolate and characterize bradyrhizobia that nodulate yardlong bean and sunnhemp in guam. | 2002 | 12234340 |
| [chemotaxis of bradyrhizobium japonicum to various organic compounds]. | the investigation of the chemotactic response of bradyrhizobium japonicum to amino acids, carbohydrates, multiatomic alcohols, organic acids, and soybean extracts showed that the extracts of some soybean varieties (chernoburaya and beskluben'kovaya) contain repellents. this indicates that the soybeans of host plants contain effectors that may play a role at the early stages of their interaction with nodule bacteria. | 2002 | 12244714 |
| divergent structure and regulatory mechanism of proline catabolic systems: characterization of the putap proline catabolic operon of pseudomonas aeruginosa pao1 and its regulation by prur, an arac/xyls family protein. | pseudomonas aeruginosa pao1 utilizes proline as the sole source of carbon and nitrogen via a bifunctional enzyme (the puta gene product) that has both proline dehydrogenase (ec 1.5.99.8) and pyrroline 5-carboxylate dehydrogenase (ec 1.5.1.12) activities. we characterized the prur-putap loci encoding the proline catabolic system of this strain. in contrast to the puta and putp (encoding proline permease) genes of other gram- negative bacteria, which are located at divergent or separate loci, nort ... | 2002 | 12270821 |
| genes encoding specific nickel transport systems flank the chromosomal urease locus of pathogenic yersiniae. | the transition metal nickel is an essential cofactor for a number of bacterial enzymes, one of which is urease. prior to its incorporation into metalloenzyme active sites, nickel must be imported into the cell. here, we report identification of two loci corresponding to nickel-specific transport systems in the gram-negative, ureolytic bacterium yersinia pseudotuberculosis. the loci are located on each side of the chromosomal urease gene cluster ureabcefgd and have the same orientation as the lat ... | 2002 | 12270829 |
| ultrafast ligand rebinding in the heme domain of the oxygen sensors fixl and dos: general regulatory implications for heme-based sensors. | heme-based oxygen sensors are part of ligand-specific two-component regulatory systems, which have both a relatively low oxygen affinity and a low oxygen-binding rate. to get insight into the dynamical aspects underlying these features and the ligand specificity of the signal transduction from the heme sensor domain, we used femtosecond spectroscopy to study ligand dynamics in the heme domains of the oxygen sensors fixl from bradyrhizobium japonicum (fixlh) and dos from escherichia coli (dosh). ... | 2002 | 12271121 |
| diversity and evolution of hydrogenase systems in rhizobia. | uptake hydrogenases allow rhizobia to recycle the hydrogen generated in the nitrogen fixation process within the legume nodule. hydrogenase (hup) systems in bradyrhizobium japonicum and rhizobium leguminosarum bv. viciae show highly conserved sequence and gene organization, but important differences exist in regulation and in the presence of specific genes. we have undertaken the characterization of hup gene clusters from bradyrhizobium sp. (lupinus), bradyrhizobium sp. (vigna), and rhizobium tr ... | 2002 | 12324339 |
| [formation and function of the bean-rhizobium symbiosis in soy plants upon introduction of strains of azotobacter and bacillus species]. | the effects of bacteria belonging to the genera azotobacter and bacillus in a mixed culture with bradyrhizobium japonicum strains on formation and function of the legume-rhizobium symbiosis of soybean plants were studied. the data showed that the bacterial compositions b. japonicum 634b + b. subtilis 5, b. japonicum 634b + a. chroococcum 20, and b. japonicum 10k + a. vinelandii 56 with a cell ratio of 1:0.1 increased the number and weight of root nodules as well as the height and weight of the a ... | 2002 | 12325300 |
| conservation of the biotin regulon and the bira regulatory signal in eubacteria and archaea. | biotin is a necessary cofactor of numerous biotin-dependent carboxylases in a variety of microorganisms. the strict control of biotin biosynthesis in escherichia coli is mediated by the bifunctional bira protein, which acts both as a biotin-protein ligase and as a transcriptional repressor of the biotin operon. little is known about regulation of biotin biosynthesis in other bacteria. using comparative genomics and phylogenetic analysis, we describe the biotin biosynthetic pathway and the bira r ... | 2002 | 12368242 |
| structure-based mechanism of o2 sensing and ligand discrimination by the fixl heme domain of bradyrhizobium japonicum. | structures of the bradyrhizobium japonicum fixl heme domain have been determined in the absence and presence of specific ligands to elucidate the detailed features of its o2 sensing mechanism. the putative roles of spin-state and steric hindrance were evaluated by the structure determination of ferrous co-bound bjfixlh and correlating its features with other ligand-bound structures. as found for no-bjfixlh, no protein conformational change was observed in co-bjfixlh, suggesting a more complicate ... | 2002 | 12390021 |
| bradyoxetin, a unique chemical signal involved in symbiotic gene regulation. | bradyrhizobium japonicum is a symbiotic bacterium that nodulates soybean. critical for the infection and establishment of this symbiosis are the bacterial nodulation genes (nod, nol, noe), which are induced in the presence of plant produced isoflavones. transcription of the nodulation genes is also controlled in a population density-dependent fashion. expression of the nod genes is maximal at low population densities, and decreases significantly at higher culture densities. population density co ... | 2002 | 12393811 |
| siderophoregenic bradyrhizobia boost yield of soybean. | after screening for siderophore (microbial iron chelator) production, of seven available cultures of soybean (glycine max l.) root nodule bradyrhizobia, one strain, bradyrhizobium japonicum ncim 2746, was selected to confirm its phytopathogenic suppression and soybean growth promotion. based on chromatographic and spectrophotometric studies, two different siderophores, a hydroxamate type (mw 734) and another catecholate type (mw 1000), were observed. randomized block design (rbd) analysis of sic ... | 2002 | 12396119 |
| in vitro induction of lipo-chitooligosaccharide production in bradyrhizobium japonicum cultures by root extracts from non-leguminous plants. | bradyrhizobium japonicum can form a n2-fixing symbiosis with compatible leguminous plants. it can also act as a plant-growth promoting rhizobacterium (pgpr) for non-legume plants, possibly through production of lipo-chitooligosaccharides (lcos), which should have the ability to induce disease resistance responses in plants. the objective of this work was to determine whether non-leguminous crop plants can induce lco formation by b. japonicum cultures. cultures treated with root extracts of soybe ... | 2002 | 12398283 |
| genomic fingerprinting of bradyrhizobium japonicum isolates by rapd and rep-pcr. | genetic diversity of indigenous bradyrhizobium japonicum population in croatia was studied by using different pcr-based fingerprinting methods. characteristic dna profiles for 20 b. japonicum field isolates and two reference strains were obtained using random primers (rapd) and two sets of repetitive primers (rep- and eric-pcr). in comparison with the rep, the eric primer set generates fingerprints of lower complexity, but still several strain-specific bands were detected. different b. japonicum ... | 2002 | 12398292 |
| a new species of devosia that forms a unique nitrogen-fixing root-nodule symbiosis with the aquatic legume neptunia natans (l.f.) druce. | rhizobia are the common bacterial symbionts that form nitrogen-fixing root nodules in legumes. however, recently other bacteria have been shown to nodulate and fix nitrogen symbiotically with these plants. neptunia natans is an aquatic legume indigenous to tropical and subtropical regions and in african soils is nodulated by allorhizobium undicola. this legume develops an unusual root-nodule symbiosis on floating stems in aquatic environments through a unique infection process. here, we analyzed ... | 2002 | 12406707 |
| metabolic engineering of acetaldehyde production by streptococcus thermophilus. | the process of acetaldehyde formation by the yogurt bacterium streptococcus thermophilus is described in this paper. attention was focused on one specific reaction for acetaldehyde formation catalyzed by serine hydroxymethyltransferase (shmt), encoded by the glya gene. in s. thermophilus, shmt also possesses threonine aldolase (ta) activity, the interconversion of threonine into glycine and acetaldehyde. in this work, several wild-type s. thermophilus strains were screened for acetaldehyde produ ... | 2002 | 12406762 |
| analysis of genomic diversity among photosynthetic stem-nodulating rhizobial strains from northeast argentina. | the genomic diversity among photosynthetic rhizobia from northeast argentina was assessed. forty six isolates obtained from naturally occurring stem and root nodules of aeschynomene rudis plants were analyzed by three molecular typing methods with different levels of taxonomic resolution: repetitive sequence-based pcr (rep-pcr) genomic fingerprinting with box and rep primers, amplified 16s rdna restriction analysis (ardra), and 16s-23s rdna intergenic spacer-restriction fragment length polymorph ... | 2002 | 12421080 |
| characterization of the norcbqd genes, encoding nitric oxide reductase, in the nitrogen fixing bacterium bradyrhizobium japonicum. | the genes norcbqd that encode the bc-type nitric oxide reductase from bradyrhizobium japonicum usda110 have been isolated and characterized. norc and norb encode the cytochrome c-containing subunit ii and cytochrome b-containing subunit i of nitric oxide reductase, respectively. norq encodes a protein with an atp/gtp-binding motif, and the predicted nord gene product shows similarity with nord from other denitrifiers. mutational analysis indicates that the two structural norc and norb genes are ... | 2002 | 12427946 |
| identification of an iron-regulated, hemin-binding outer membrane protein in sinorhizobium meliloti. | rhizobia are soil bacteria that are able to establish symbiotic associations with leguminous hosts. in iron-limited environments these bacteria can use iron present in heme or heme compounds (hemoglobin, leghemoglobin). here we report the presence in sinorhizobium meliloti of an iron-regulated outer membrane protein that is able to bind hemin but not hemoglobin. protein assignment was done by matrix-assisted laser desorption ionization-time of flight mass spectrometry. tryptic peptides correlate ... | 2002 | 12450806 |
| transcriptional response of soybean suspension-cultured cells induced by nod factors obtained from bradyrhizobium japonicum usda110. | genes responding to nod factors were picked up by the application of a differential display method for soybean suspension-cultured cells. forty-five cdna fragments derived from such genes were detected. seven fragments (ssc1-ssc7) were successfully cloned. the putative product of genes corresponding to ssc1 was estimated to be a disease-resistance protein relating to the induction of the plant defense response against pathogens, and that corresponding to ssc7 was a sucrose transporter. amino aci ... | 2002 | 12461131 |
| cloning and expression of the gene for soybean hydroxyisourate hydrolase. localization and implications for function and mechanism. | the gene encoding hydroxyisourate hydrolase, a novel ureide-metabolizing enzyme, has been cloned from soybean (glycine max). the gene encodes a protein that is 560 amino acids in length and contains a 31-amino acid signal sequence at the n terminus that is not present in the mature protein. the presence of two skl motifs near the c terminus suggests that the protein resides in the peroxisome. this expectation is borne out by results from immunogold electron microscopy, which revealed that hydrox ... | 2002 | 12481089 |
| mutational and transcriptional analysis of the type iii secretion system of bradyrhizobium japonicum. | sequencing the symbiotic region of bradyrhizobium japonicum revealed a gene cluster (tts) encoding a type iii secretion system (ttss) that is similar to those found in mesorhizobium loti maff303099 and rhizobium strain ngr234. in addition to genes that are likely to encode structural core components of the ttss, the cluster contains several open reading frames that are found exclusively in rhizobia or that are specific to b. japonicum. depending on the host, mutations within this cluster affecte ... | 2002 | 12481995 |
| arsenite oxidase aox genes from a metal-resistant beta-proteobacterium. | the beta-proteobacterial strain ulpas1, isolated from an arsenic-contaminated environment, is able to efficiently oxidize arsenite [as(iii)] to arsenate [as(v)]. mutagenesis with a lacz-based reporter transposon yielded two knockout derivatives deficient in arsenite oxidation. sequence analysis of the dna flanking the transposon insertions in the two mutants identified two adjacent open reading frames, named aoxa and aoxb, as well as a putative promoter upstream of the aoxa gene. reverse transcr ... | 2003 | 12486049 |
| biochemical and mutational characterization of the heme chaperone ccme reveals a heme binding site. | ccme is a heme chaperone that binds heme transiently in the periplasm of escherichia coli and delivers it to newly synthesized and exported c-type cytochromes. the chemical nature of the covalent bond between heme and h130 is not known. we have purified soluble histidine-tagged ccme and present its spectroscopic characteristics in the visible range. alanine scanning mutagenesis of conserved amino acids revealed that h130 is the only residue found to be strictly required for heme binding and deli ... | 2003 | 12486054 |
| evidence that carbon dioxide enrichment alleviates ureide-induced decline of nodule nitrogenase activity. | the hypothesis that elevated [co(2)] alleviates ureide inhibition of n(2)-fixation was tested. short-term responses of the acetylene reduction assay (ara), ureide accumulation and total non-structural carbohydrate (tnc) levels were measured following addition of ureide to the nutrient solution of hydroponically grown soybean. the plants were exposed to ambient (360 micromol mol(-1)) or elevated (700 micromol mol(-1)) [co(2)]. addition of 5 and 10 mm ureide to the nutrient solution inhibited n(2) ... | 2003 | 12495923 |
| characterization of rhizobia that nodulate legume species of the genus lespedeza and description of bradyrhizobium yuanmingense sp. nov. | legume species belonging to the genus lespedeza are annual or perennial herb or shrub plants that grow in the northern hemisphere. they are known for the formation of root nodules, but little information is available about their microsymbionts. in this study, 58 root-nodule isolates from lespedeza spp., obtained from china and the usa, were characterized using numerical taxonomic analysis of phenotypic features, sds-page analysis of whole-cell proteins, dna-dna hybridization, 16s rrna gene seque ... | 2002 | 12508891 |
| features of rhodobacter sphaeroides ccmfh. | in this study, the in vivo function and properties of two cytochrome c maturation proteins, ccmf and ccmh from rhodobacter sphaeroides, were analyzed. strains lacking ccmh or both ccmf and ccmh are unable to grow under anaerobic conditions where c-type cytochromes are required, demonstrating their critical role in the assembly of these electron carriers. consistent with this observation, strains lacking both ccmf and ccmh are deficient in c-type cytochromes when assayed under permissive growth c ... | 2003 | 12511487 |
| tmrna is required for correct timing of dna replication in caulobacter crescentus. | ssra, or tmrna, is a small rna that interacts with selected translating ribosomes to target the nascent polypeptides for degradation. here we report that ssra activity is required for normal timing of the g(1)-to-s transition in caulobacter crescentus. a deletion of the ssra gene, or of the gene encoding smpb, a protein required for ssra activity, results in a specific delay in the cell cycle during the g(1)-to-s transition. the ssra deletion phenotype is not due to accumulation of stalled ribos ... | 2003 | 12511504 |
| nodulation gene regulation in bradyrhizobium japonicum: a unique integration of global regulatory circuits. | | 2003 | 12513971 |
| a host-specific bacteria-to-plant signal molecule (nod factor) enhances germination and early growth of diverse crop plants. | lipo-chitooligosaccharides (lcos), or nod factors, are host-specific bacteria-to-plant signal molecules essential for the establishment of a successful n(2)-fixing legume-rhizobia symbiosis. at submicromolar concentrations nod factors induce physiological changes in host and non-host plants. here we show that the nod factor nod bj v(c18:1,mefuc) of bradyrhizobium japonicum 532c enhances germination of a variety of economically important plants belonging to diverse botanical families: zea mays, o ... | 2003 | 12520335 |
| iscce1 and iscce2, two novel insertion sequences in clostridium cellulolyticum. | two new insertion sequences, iscce1 and iscce2, were found to be inserted into the cipc gene of spontaneous mutants of clostridium cellulolyticum. in these insertional mutants, the cipc gene was disrupted either by iscce1 alone or by both iscce1 and iscce2. iscce1 is 1,292 bp long and has one open reading frame. the open reading frame encodes a putative 348-amino-acid protein with significant levels of identity with putative proteins having unknown functions and with some transposases belonging ... | 2003 | 12533447 |
| characterization of helicobacter pylori nickel metabolism accessory proteins needed for maturation of both urease and hydrogenase. | previous studies demonstrated that two accessory proteins, hypa and hypb, play a role in nickel-dependent maturation of both hydrogenase and urease in helicobacter pylori. here, the two proteins were purified and characterized. hypa bound two ni(2+) ions per dimer with positive cooperativity (hill coefficient, approximately 2.0). the dissociation constants k(1) and k(2) for ni(2+) were 58 and 1.3 microm, respectively. studies on purified site-directed mutant proteins in each of the five histidin ... | 2003 | 12533448 |
| requirements for cu(a) and cu-s center assembly of nitrous oxide reductase deduced from complete periplasmic enzyme maturation in the nondenitrifier pseudomonas putida. | bacterial nitrous oxide (n(2)o) reductase is the terminal oxidoreductase of a respiratory process that generates dinitrogen from n(2)o. to attain its functional state, the enzyme is subjected to a maturation process which involves the protein-driven synthesis of a unique copper-sulfur cluster and metallation of the binuclear cu(a) site in the periplasm. there are seven putative maturation factors, encoded by nosa, nosd, nosf, nosy, nosl, nosx, and sco. we wanted to determine the indispensable pr ... | 2003 | 12533464 |
| prediction and overview of the rpon-regulon in closely related species of the rhizobiales. | in the rhizobia, a group of symbiotic gram-negative soil bacteria, rpon (sigma54, sigman, ntra) is best known as the sigma factor enabling transcription of the nitrogen fixation genes. recent reports, however, demonstrate the involvement of rpon in other symbiotic functions, although no large-scale effort has yet been undertaken to unravel the rpon-regulon in rhizobia. we screened two complete rhizobial genomes (mesorhizobium loti, sinorhizobium meliloti) and four symbiotic regions (rhizobium et ... | 2002 | 12537565 |
| post-genomic insights into plant nodulation symbioses. | several legume genes involved in establishing nitrogen fixation have been discovered using functional genomics; when mutated, the genes affect symbioses, and all encode receptor kinases. this provides long-awaited insights into a complex plant-bacterium interaction and heralds the possibility of extending the range of plants susceptible to nitrogen-fixing nodulation. | 2003 | 12540294 |
| [study on the improvement of plasmid stability in soybean rhizobia]. | by using luxab as the report genes, 3.2 kb parcba/de gene fragment from ptr102 was inserted into plafr3 which contained a 3.7 kb enhancing fragment and deleted its cos site. recombinant plasmids phn155 and phn156 were obtained. contrasted plasmids phn157 and phn158 which contained cos site were also constructed. these four plasmids were transferred into sinorhizobium fredii hn01 by tri-parental mating, and plasmid phn155 and phn158 were introduced into bradyrhizobium japonicum ta11 by two-parent ... | 2000 | 12548995 |
| characterization of the nodulation plasmid encoded chemoreceptor gene mcpg from rhizobium leguminosarum. | in general, chemotaxis in rhizobium has not been well characterized. methyl accepting chemotaxis proteins are sensory proteins important in chemotaxis of numerous bacteria, but their involvement in rhizobium chemotaxis is unclear and merits further investigation. | 2003 | 12553885 |
| [study on polyphasic taxonomy of rhizobia isolated from lespedeza species]. | the diversity of rhizobia isolated from lespedeza spp. was determined on the basis of numerical analysis of phenotypic characteristics, sodium dodecyl sulfate-polyacrylarmide gel electrophoresis (sds-page) of proteins, dna-dna homology and restriction fragment length polymorphism (rflp) analysis of 16s-ribosomal dna genes. according to numerical analysis of 125 phenotypic characteristics, strains were divided into two groups at a similarity level of 67%. group i included all the fast-growing str ... | 1999 | 12555566 |
| characterization of ndvd, the third gene involved in the synthesis of cyclic beta-(1 --> 3),(1 --> 6)-d-glucans in bradyrhizobium japonicum. | previously, we identified two genes in bradyrhizobium japonicum (ndvb, ndvc) that are required for cyclic beta-(1 --> 3),(1 --> 6)-d-glucan synthesis and successful symbiotic interaction with soybean (glycine max). in this study, we report a new open reading frame (orf1) located in the intergenic region between ndvb and ndvc, which is essential for beta-glucan synthesis and effective nodulation of g. max. this new gene is designated ndvd (nodule development). the ndvd translation product has a p ... | 2002 | 12556128 |
| isolation and molecular characterization of pmg160, a mobilizable cryptic plasmid from rhodobacter blasticus. | a 3.4-kb cryptic plasmid was obtained from a new isolate of rhodobacter blasticus. this plasmid, designated pmg160, was mobilizable by the conjugative strain escherichia coli s17.1 into rhodobacter sphaeroides, rhodobacter capsulatus, and rhodopseudomonas palustris. it replicated in the latter strains but not in rhodospirillum rubrum, rhodocyclus gelatinosus, or bradyrhizobium species. plasmid pmg160 was stably maintained in r. sphaeroides for more than 100 generations in the absence of selectio ... | 2003 | 12570988 |
| comparative genetic diversity of the narg, nosz, and 16s rrna genes in fluorescent pseudomonads. | the diversity of the membrane-bound nitrate reductase (narg) and nitrous oxide reductase (nosz) genes in fluorescent pseudomonads isolated from soil and rhizosphere environments was characterized together with that of the 16s rrna gene by a pcr-restriction fragment length polymorphism assay. fragments of 1,008 bp and 1,433 bp were amplified via pcr with primers specific for the narg and nosz genes, respectively. the presence of the narg and nosz genes in the bacterial strains was confirmed by hy ... | 2003 | 12571023 |
| phenotypic and genotypic diversity of rhizobia nodulating pterocarpus erinaceus and p. lucens in senegal. | a total of fifty root nodules isolates of fast-growing and slow growing rhizobia from pterocarpus ennaceus and pterocarpus lucens respectively native of sudanean and sahelian regions of senegal were characterized. these isolates were compared to representative strains of known rhizobial species. twenty-two new isolates were slow growers and twenty-eight were fast growers. a polyphasic approach was performed including comparative total protein sodium dodecyl sulphate polyacrylamide gel (sds-page) ... | 2002 | 12583718 |
| hemin binding, functional expression, and complementation analysis of pap 31 from bartonella henselae. | growth of bartonella henselae is strongly heme dependent, and b. henselae is unable to synthesize heme itself. at least five outer membrane-associated proteins from b. henselae bind hemin, including the 31-kda protein designated pap31. the gene of this protein was heterologously expressed in escherichia coli m15(prep4) and detected with monoclonal antibodies in the outer membrane fraction. complementation of the hema-deficient mutant e. coli k-12 eb53 (arob tsx malt hema) with pap31 demonstrated ... | 2003 | 12591895 |
| complete genomic sequence of nitrogen-fixing symbiotic bacterium bradyrhizobium japonicum usda110. | the complete nucleotide sequence of the genome of a symbiotic bacterium bradyrhizobium japonicum usda110 was determined. the genome of b. japonicum was a single circular chromosome 9,105,828 bp in length with an average gc content of 64.1%. no plasmid was detected. the chromosome comprises 8317 potential protein-coding genes, one set of rrna genes and 50 trna genes. fifty-two percent of the potential protein genes showed sequence similarity to genes of known function and 30% to hypothetical gene ... | 2002 | 12597275 |
| complete genomic sequence of nitrogen-fixing symbiotic bacterium bradyrhizobium japonicum usda110 (supplement). | | 2002 | 12597279 |
| molecular analysis of the multiple groel proteins of chlamydiae. | genome sequencing revealed that all six chlamydiae genomes contain three groel-like genes (groel1, groel2, and groel3). phylogenetic analysis of groel1, groel2, and groel3 indicates that these genes are likely to have been present in chlamydiae since the beginning of the lineage. comparison of deduced amino acid sequences of the three groel genes with those of other organisms showed high homology only for groel1, although comparison of critical amino acid residues that are required for polypepti ... | 2003 | 12618460 |
| transcriptome analysis of sinorhizobium meliloti during symbiosis. | rhizobia induce the formation on specific legumes of new organs, the root nodules, as a result of an elaborated developmental program involving the two partners. in order to contribute to a more global view of the genetics underlying this plant-microbe symbiosis, we have mined the recently determined sinorhizobium meliloti genome sequence for genes potentially relevant to symbiosis. we describe here the construction and use of dedicated nylon macroarrays to study simultaneously the expression of ... | 2003 | 12620125 |
| fnr is involved in oxygen control of herbaspirillum seropedicae n-truncated nifa protein activity in escherichia coli. | herbaspirillum seropedicae is an endophytic diazotroph belonging to the beta-subclass of the class proteobacteria, which colonizes many members of the gramineae. the activity of the nifa protein, a transcriptional activator of nif genes in h. seropedicae, is controlled by ammonium ions through its n-terminal domain and by oxygen through mechanisms that are not well understood. here we report that the nifa protein of h. seropedicae is inactive and more susceptible to degradation in an fnr escheri ... | 2003 | 12620839 |
| two families of mechanosensitive channel proteins. | mechanosensitive (ms) channels that provide protection against hypoosmotic shock are found in the membranes of organisms from the three domains of life: bacteria, archaea, and eucarya. two families of ubiquitous ms channels are recognized, and these have been designated the mscl and mscs families. a high-resolution x-ray crystallographic structure is available for a member of the mscl family, and extensive molecular genetic, biophysical, and biochemical studies conducted in many laboratories hav ... | 2003 | 12626684 |
| dual intracellular localization and targeting of aminoimidazole ribonucleotide synthetase in cowpea. | de novo purine biosynthesis is localized to both mitochondria and plastids isolated from bradyrhizobium sp.-infected cells of cowpea (vigna unguiculata l. walp) nodules, but several of the pathway enzymes, including aminoimidazole ribonucleotide synthetase (airs [ec 6.3.3.1], encoded by vupur5), are encoded by single genes. immunolocalization confirmed the presence of airs protein in both organelles. enzymatically active airs was purified separately from nodule mitochondria and plastids. n-termi ... | 2003 | 12644656 |
| identification and characterization of a mandelamide hydrolase and an nad(p)+-dependent benzaldehyde dehydrogenase from pseudomonas putida atcc 12633. | the enzymes of the mandelate metabolic pathway permit pseudomonas putida atcc 12633 to utilize either or both enantiomers of mandelate as the sole carbon source. the genes encoding the mandelate pathway were found to lie on a single 10.5-kb restriction fragment. part of that fragment was shown to contain the genes coding for mandelate racemase, mandelate dehydrogenase, and benzoylformate decarboxylase arranged in an operon. here we report the sequencing of the remainder of the restriction fragme ... | 2003 | 12670968 |
| phylogenetic analysis of anaerobic psychrophilic enrichment cultures obtained from a greenland glacier ice core. | the examination of microorganisms in glacial ice cores allows the phylogenetic relationships of organisms frozen for thousands of years to be compared with those of current isolates. we developed a method for aseptically sampling a sediment-containing portion of a greenland ice core that had remained at -9 degrees c for over 100,000 years. epifluorescence microscopy and flow cytometry results showed that the ice sample contained over 6 x 10(7) cells/ml. anaerobic enrichment cultures inoculated w ... | 2003 | 12676695 |
| the enigmatic mitochondrial orf ymf39 codes for atp synthase chain b. | ymf39 is a conserved hypothetical protein-coding gene found in mitochondrial genomes of land plants and certain protists. we speculated earlier, based on a weak sequence similarity between ymf39 from a green alga and the atpf gene product from bradyrhizobium, that ymf39 might code for subunit b of mitochondrial f(0)f(1)-atp synthase. to test this hypothesis, we have sequenced ymf39 from five protists with minimally derived mitochondrial genomes, the jakobids. in addition, we isolated the mitocho ... | 2003 | 12711680 |
| fur is not the global regulator of iron uptake genes in rhizobium leguminosarum. | rhizobium leguminosarum fur mutants were unaffected in fe-dependent regulation of several operons that specify different fe uptake systems, yet cloned r. leguminosarum fur partially corrected an escherichia coli fur mutant and r. leguminosarum fur protein bound to canonical fur boxes. the lack of a phenotype in fur mutants is not due to functional redundancy with irr, another member of the fur superfamily found in the rhizobia, since irr fur double mutants are also unaffected in fe-responsive re ... | 2003 | 12724397 |
| structural and functional defects caused by point mutations in the alpha-crystallin domain of a bacterial alpha-heat shock protein. | the diverse family of alpha-crystallin-type small heat shock proteins (alpha-hsps or shsps) is characterised by a central, moderately conserved alpha-crystallin domain. oligomerisation followed by dissociation of subparticles is thought to be a prerequisite for chaperone function. we demonstrate that hsph, a bacterial alpha-hsp from the soybean-symbiont bradyrhizobium japonicum, assembles into dynamic complexes freely exchanging subunits with homologous and heterologous complexes. the importance ... | 2003 | 12729765 |