Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| the genome sequence of the facultative intracellular pathogen brucella melitensis. | brucella melitensis is a facultative intracellular bacterial pathogen that causes abortion in goats and sheep and malta fever in humans. the genome of b. melitensis strain 16m was sequenced and found to contain 3,294,935 bp distributed over two circular chromosomes of 2,117,144 bp and 1,177,787 bp encoding 3,197 orfs. by using the bioinformatics suite ergo, 2,487 (78%) orfs were assigned functions. the origins of replication of the two chromosomes are similar to those of other alpha-proteobacter ... | 2002 | 11756688 |
| [effect of ph on nodulation of soybean rhizobia from weifang and huayuankou soils]. | the effect of ph on the nodulation of sinorhizobium fredii and bradyrhizobium japonicum was examined by analyzing the indigent soybean rhizobia, predominant indigent rhizobia, and specific rhizobia, respectively. the results showed that very acid and very alkaline environment could retard the nodulation and inhibit the growth of the rhizobia. sinorhizohium fredii could endure environment more strongly than bradyrhizobium japonicum, and had a high competitive nodulation capacity. bradyhizobium ja ... | 2001 | 11758403 |
| the bradyrhizobium japonicum hsfa gene exhibits a unique developmental expression pattern in cowpea nodules. | the bradyrhizobium japonicum host-specific fixation gene hsfa was identified as essential for nitrogen fixation on cowpea, but not required for nitrogen fixation on soybean or siratro. the dna sequence of the hsfa promoter contains a consensus rpon, -24/-12 binding site, suggesting the involvement of a regulatory protein that binds to an upstream activating sequence (uas). to further explore the regulation of this interesting gene, serial deletions of the hsfa promoter were made and fused with t ... | 2001 | 11763126 |
| bradyrhizobium japonicum mutants with enhanced sensitivity to genistein resulting in altered nod gene regulation. | bradyrhizobium japonicum mutants with altered nod gene induction characteristics were isolated by screening mutants for genistein-independent nod gene expression. plasmid pzb32, carrying a nody::lacz transcriptional gene fusion, was introduced into b. japonicum cells that had been subjected to uv mutagenesis. ten independent transformants producing a blue color on plates containing 5bromo-4chloro-3indolyl-beta-d-galactopyranoside but lacking genistein, indicative of constitutive expression of th ... | 2001 | 11768535 |
| ammonia- and nitrite-oxidizing bacterial communities in a pilot-scale chloraminated drinking water distribution system. | nitrification in drinking water distribution systems is a common operational problem for many utilities that use chloramines for secondary disinfection. the diversity of ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nob) in the distribution systems of a pilot-scale chloraminated drinking water treatment system was characterized using terminal restriction fragment length polymorphism (t-rflp) analysis and 16s rrna gene (ribosomal dna [rdna]) cloning and sequencing. for ammonia ... | 2002 | 11772611 |
| transcriptional regulation of nostoc hydrogenases: effects of oxygen, hydrogen, and nickel. | the transcription of structural genes encoding two hydrogenases in n(2)-fixing cultures of the cyanobacteria nostoc muscorum and nostoc sp. strain pcc 73102 were examined by reverse transcription-pcr. a low level of oxygen and addition of nickel induce higher transcript levels of both hydrogenases, whereas molecular hydrogen has a positive effect on the transcription of the genes encoding only the uptake hydrogenase. | 2002 | 11772661 |
| nolx of sinorhizobium fredii usda257, a type iii-secreted protein involved in host range determination, iis localized in the infection threads of cowpea (vigna unguiculata [l.] walp) and soybean (glycine max [l.] merr.) nodules. | sinorhizobium fredii usda257 forms nitrogen-fixing nodules on soybean (glycine max [l.] merr.) in a cultivar-specific manner. this strain forms nodules on primitive soybean cultivars but fails to nodulate agronomically improved north american cultivars. soybean cultivar specificity is regulated by the nolxwbtuv locus, which encodes part of a type iii secretion system (ttss). nolx, a soybean cultivar specificity protein, is secreted by ttss and shows homology to hrpf of the plant pathogen xanthom ... | 2002 | 11790754 |
| integrative genetic element that reverses the usual target gene orientation. | a genetic element integrating site specifically into a prokaryotic gene usually carries a copy of the 3' portion of that gene that restores the active gene even as the original is disrupted. a cryptic element in mesorhizobium loti instead carries a copy of the 5' end of the trna gene into which it integrated. this has implications for the evolution of new integrase-site combinations. | 2002 | 11790760 |
| interaction between the bacterial iron response regulator and ferrochelatase mediates genetic control of heme biosynthesis. | the heme biosynthetic pathway culminates with the insertion of iron into protoporphyrin catalyzed by ferrochelatase. the bradyrhizobium japonicum iron response regulator (irr) protein represses the pathway at an early step under iron limitation to prevent protoporphyrin synthesis from exceeding iron availability. here, we show that irr interacts directly with ferrochelatase and responds to iron via the status of heme and protoporphyrin localized at the site of heme synthesis. in the presence of ... | 2002 | 11804594 |
| chromosomal locus that affects pathogenicity of rhodococcus fascians. | the gram-positive plant pathogen rhodococcus fascians provokes leafy gall formation on a wide range of plants through secretion of signal molecules that interfere with the hormone balance of the host. crucial virulence genes are located on a linear plasmid, and their expression is tightly controlled. a mutant with a mutation in a chromosomal locus that affected virulence was isolated. the mutation was located in gene vica, which encodes a malate synthase and is functional in the glyoxylate shunt ... | 2002 | 11807072 |
| molecular characterization and substrate specificity of nitrobenzene dioxygenase from comamonas sp. strain js765. | comamonas sp. strain js765 can grow with nitrobenzene as the sole source of carbon, nitrogen, and energy. we report here the sequence of the genes encoding nitrobenzene dioxygenase (nbdo), which catalyzes the first step in the degradation of nitrobenzene by strain js765. the components of nbdo were designated reductase(nbz), ferredoxin(nbz), oxygenase(nbzalpha), and oxygenase(nbzbeta), with the gene designations nbzaa, nbzab, nbzac, and nbzad, respectively. sequence analysis showed that the comp ... | 2002 | 11823201 |
| integration sites for genetic elements in prokaryotic trna and tmrna genes: sublocation preference of integrase subfamilies. | most classical integrases of prokaryotic genetic elements specify integration into trna or tmrna genes. sequences shared between element and host integration sites suggest that crossover can occur at any of three sublocations within a trna gene, two with flanking symmetry (anticodon-loop and t-loop tdna) and the third at the asymmetric 3' end of the gene. integrase phylogeny matches this classification: integrase subfamilies use exclusively either the symmetric sublocations or the asymmetric sub ... | 2002 | 11842097 |
| oxygen deficiency responsive gene expression in chlamydomonas reinhardtii through a copper-sensing signal transduction pathway. | chlamydomonas reinhardtii activates cpx1, cyc6, and crd1, encoding, respectively, coproporphyrinogen oxidase, cytochrome c(6), and a novel di-iron enzyme when transferred to oxygen-deficient growth conditions. this response is physiologically relevant because c. reinhardtii experiences these growth conditions routinely, and furthermore, one of the target genes, crd1, is functionally required for normal growth under oxygen-depleted conditions. the same genes are activated also in response to copp ... | 2002 | 11842150 |
| soybean enod40 encodes two peptides that bind to sucrose synthase. | enod40 is expressed at an early stage in root nodule organogenesis in legumes. identification of enod40 homologs in nonleguminous plants suggests that this gene may have a more general biological function. in vitro translation of soybean enod40 mrna in wheat germ extracts revealed that the conserved nucleotide sequence at the 5' end (region i) encodes two peptides of 12 and 24 aa residues (peptides a and b). these peptides are synthesized de novo from very short, overlapping orfs. appropriate or ... | 2002 | 11842184 |
| quantitative assessment of oxygen availability: perceived aerobiosis and its effect on flux distribution in the respiratory chain of escherichia coli. | despite a large number of studies on the role of oxygen in cellular processes, there is no consensus as to how oxygen availability to the cell should be defined, let alone how it should be quantified. here, a quantitative definition for oxygen availability (perceived aerobiosis) is presented; the definition is based on a calibration with reference to the minimal oxygen supply rate needed for fully oxidative catabolism (i.e., complete conversion of the energy source to co(2) and water for glucose ... | 2002 | 11844770 |
| conserved low-affinity nickel-binding amino acids are essential for the function of the nickel permease nixa of helicobacter pylori. | nickel acquisition is necessary for urease activity, a major virulence factor of the human gastric pathogen helicobacter pylori. the nickel permease nixa of h. pylori is a member of the single-component nickel-cobalt transporter family. to identify functionally relevant amino acids of nixa, single-site exchanges were introduced into nixa via pcr-based mutagenesis. this study investigated one of the recognition motifs for this family in transmembrane segment iii and other conserved amino acids, m ... | 2002 | 11844775 |
| comparison of molecular and antibiotic resistance profile methods for the population analysis of bradyrhizobium spp. (tgx) isolates that nodulate the new tgx soybean cultivars in africa. | comparison of molecular and antibiotic resistance profile methods to identify an easy method that can differentiate between strains of introduced bradyrhizobium japonicum and the indigenous bradyrhizobium spp. (tgx) isolates which nodulate the newly developed tgx soybean cultivars in africa. | 2002 | 11849334 |
| crystallization and preliminary x-ray crystallographic analysis of malonamidase e2, an amidase signature family member. | malonamidase e2 from bradyrhizobium japonicum catalyzes the hydrolysis of malonamate. the enzyme belongs to an amidase signature family which has a highly conserved serine- and glycine-rich sequence over a stretch of approximately 45 amino acids. more than 100 known or predicted members belonging to this family, whose biological functions vary widely, can be identified in sequence databases. although urgently needed, no three-dimensional structure of any protein of this family is yet available. ... | 2002 | 11856856 |
| compilation and analysis of group ii intron insertions in bacterial genomes: evidence for retroelement behavior. | group ii introns are novel genetic elements that have properties of both catalytic rnas and retroelements. initially identified in organellar genomes of plants and lower eukaryotes, group ii introns are now being discovered in increasing numbers in bacterial genomes. few of the newly sequenced bacterial introns are correctly identified or annotated by those who sequenced them. here we have compiled and thoroughly analyzed group ii introns and their fragments in bacterial dna sequences reported t ... | 2002 | 11861899 |
| the aquatic budding bacterium blastobacter denitrificans is a nitrogen-fixing symbiont of aeschynomene indica. | blastobacter spp. are freshwater bacteria that form rosette structures by cellular attachment to a common base. comparative analyses of ribosomal 16s rrna gene and internally transcribed spacer region sequences indicated that b. denitrificans is a member of the alpha-subdivision of proteobacteria. among the alpha-proteobacteria, b. denitrificans was related to a cluster of genera, including rhodopseudomonas palustris, afipia felis, nitrobacter hamburgensis, and bradyrhizobium spp. although the p ... | 2002 | 11872460 |
| effects of t4 lysozyme release from transgenic potato roots on bacterial rhizosphere communities are negligible relative to natural factors. | rhizosphere bacterial communities of two transgenic potato lines which produce t4 lysozyme for protection against bacterial infections were analyzed in comparison to communities of wild-type plants and transgenic controls not harboring the lysozyme gene. rhizosphere samples were taken from young, flowering, and senescent plants at two field sites in three consecutive years. the communities were characterized in a polyphasic approach. cultivation-dependent methods included heterotrophic plate cou ... | 2002 | 11872484 |
| oxygen-mediated regulation of porphobilinogen formation in rhodobacter capsulatus. | a rhodobacter capsulatus hemc mutant has been isolated and used to show that oxygen regulates the intracellular levels of porphobilinogen. experiments using a hemb-cat gene fusion demonstrated that oxygen does not transcriptionally regulate hemb transcription. porphobilinogen synthase activity is not regulated by oxygen nor is the enzyme feedback inhibited by hemin or protoporphyrin ix. it was demonstrated that less than 20% of [(14)c]aminolevulinate was incorporated into bacteriochlorophyll, su ... | 2002 | 11872720 |
| rubredoxins involved in alkane oxidation. | rubredoxins (rds) are essential electron transfer components of bacterial membrane-bound alkane hydroxylase systems. several rd genes associated with alkane hydroxylase or rd reductase genes were cloned from gram-positive and gram-negative organisms able to grow on n-alkanes (alk-rds). complementation tests in an escherichia coli recombinant containing all pseudomonas putida gpo1 genes necessary for growth on alkanes except rd 2 (alkg) and sequence comparisons showed that the alk-rds can be divi ... | 2002 | 11872724 |
| a two-component regulator mediates population-density-dependent expression of the bradyrhizobium japonicum nodulation genes. | bradyrhizobium japonicum nod gene expression was previously shown to be population density dependent. induction of the nod genes is highest at low culture density and repressed at high population densities. this repression involves both nola and nodd2 and is mediated by an extracellular factor found in b. japonicum conditioned medium. nola and nodd2 expression is maximal at high population densities. we demonstrate here that a response regulator, encoded by nwsb, is required for the full express ... | 2002 | 11872728 |
| hydrogenases and hydrogen metabolism of cyanobacteria. | cyanobacteria may possess several enzymes that are directly involved in dihydrogen metabolism: nitrogenase(s) catalyzing the production of hydrogen concomitantly with the reduction of dinitrogen to ammonia, an uptake hydrogenase (encoded by hupsl) catalyzing the consumption of hydrogen produced by the nitrogenase, and a bidirectional hydrogenase (encoded by hoxfuyh) which has the capacity to both take up and produce hydrogen. this review summarizes our knowledge about cyanobacterial hydrogenases ... | 2002 | 11875125 |
| alpha-crystallin-type heat shock proteins: socializing minichaperones in the context of a multichaperone network. | alpha-crystallins were originally recognized as proteins contributing to the transparency of the mammalian eye lens. subsequently, they have been found in many, but not all, members of the archaea, bacteria, and eucarya. most members of the diverse alpha-crystallin family have four common structural and functional features: (i) a small monomeric molecular mass between 12 and 43 kda; (ii) the formation of large oligomeric complexes; (iii) the presence of a moderately conserved central region, the ... | 2002 | 11875128 |
| trna is the source of low-level trans-zeatin production in methylobacterium spp. | pink-pigmented facultatively methylotrophic bacteria (ppfms), classified as methylobacterium spp., are persistent colonizers of plant leaf surfaces. reports of ppfm-plant dialogue led us to examine cytokinin production by ppfms. using immunoaffinity and high-performance liquid chromatography (hplc) purification, we obtained 22 to 111 ng of trans-zeatin per liter from culture filtrates of four ppfm leaf isolates (from arabidopsis, barley, maize, and soybean) and of a methylobacterium extorquens t ... | 2002 | 11889088 |
| metabolic signals that lead to control of cbb gene expression in rhodobacter capsulatus. | various mutant strains were used to examine the regulation and metabolic control of the calvin-benson-bassham (cbb) reductive pentose phosphate pathway in rhodobacter capsulatus. previously, a ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco)-deficient strain (strain sbi/ii) was found to show enhanced levels of cbb(i) and cbb(ii) promoter activities during photoheterotrophic growth in the presence of dimethyl sulfoxide. with this strain as the starting point, additional mutations were ma ... | 2002 | 11889097 |
| the cytochrome c maturation locus of legionella pneumophila promotes iron assimilation and intracellular infection and contains a strain-specific insertion sequence element. | previously, we obtained a legionella pneumophila mutant, nu208, that is hypersensitive to iron chelators when grown on standard legionella media. here, we demonstrate that nu208 is also impaired for growth in media that simply lack their iron supplement. the mutant was not, however, impaired for the production of legiobactin, the only known l. pneumophila siderophore. importantly, nu208 was also highly defective for intracellular growth in human u937 cell macrophages and hartmannella and acantha ... | 2002 | 11895946 |
| species-specific inhibition of porphobilinogen synthase by 4-oxosebacic acid. | porphobilinogen synthase (pbgs) catalyzes the condensation of two molecules of 5-aminolevulinic acid (ala), an essential step in tetrapyrrole biosynthesis. 4-oxosebacic acid (4-osa) and 4,7-dioxosebacic acid (4,7-dosa) are bisubstrate reaction intermediate analogs for pbgs. we show that 4-osa is an active site-directed irreversible inhibitor for escherichia coli pbgs, whereas human, pea, pseudomonas aeruginosa, and bradyrhizobium japonicum pbgs are insensitive to inhibition by 4-osa. some varian ... | 2002 | 11909869 |
| 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 |
| diversity of nitrite reductase (nirk and nirs) gene fragments in forested upland and wetland soils. | the genetic heterogeneity of nitrite reductase gene (nirk and nirs) fragments from denitrifying prokaryotes in forested upland and marsh soil was investigated using molecular methods. nirk gene fragments could be amplified from both soils, whereas nirs gene fragments could be amplified only from the marsh soil. pcr products were cloned and screened by restriction fragment length polymorphism (rflp), and representative fragments were sequenced. the diversity of nirk clones was lower than the dive ... | 2002 | 11916709 |
| 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 |
| raspberry3 gene encodes a novel protein important for embryo development. | we identified a new gene that is interrupted by t-dna in an arabidopsis embryo mutant called raspberry3. raspberry3 has "raspberry-like" cellular protuberances with an enlarged suspensor characteristic of other raspberry embryo mutants, and is arrested morphologically at the globular stage of embryo development. the predicted raspberry3 protein has domains found in proteins present in prokaryotes and algae chloroplasts. computer prediction analysis suggests that the raspberry3protein may be loca ... | 2002 | 12068112 |
| 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 of the neurospora set domain protein dim-5, a histone h3 lysine methyltransferase. | adomet-dependent methylation of histones is part of the "histone code" that can profoundly influence gene expression. we describe the crystal structure of neurospora dim-5, a histone h3 lysine 9 methyltranferase (hkmt), determined at 1.98 a resolution, as well as results of biochemical characterization and site-directed mutagenesis of key residues. this set domain protein bears no structural similarity to previously characterized adomet-dependent methyltransferases but includes notable features ... | 2002 | 12372305 |
| 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 |
| generalized gap model for bacterial artificial chromosome clone fingerprint mapping and shotgun sequencing. | we develop an extension to the lander-waterman theory for characterizing gaps in bacterial artificial chromosome fingerprint mapping and shotgun sequencing projects. it supports a larger set of descriptive statistics and is applicable to a wider range of project parameters. we show that previous assertions regarding inconsistency of the lander-waterman theory at higher coverages are incorrect and that another well-known but ostensibly different model is in fact the same. the apparent paradox of ... | 2002 | 12466299 |
| 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 |