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??????: Rhizobium etli  

Full Text Available Bacteria Rhizobium/Agrobacterium group Rhizobium etli Rhizobium etli (scientific name) NCBI 2944 iam_microbe_ident2?taxonomy_id=29449 target=_blank>?? ????????? (??????): 1 ?????H15 (?????? - ?? ?????????): 1

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Metabolic Reconstruction and Modeling of Nitrogen Fixation in Rhizobium etli  

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Rhizobiaceas are bacteria that fix nitrogen during symbiosis with plants. This symbiotic relationship is crucial for the nitrogen cycle, and understanding symbiotic mechanisms is a scientific challenge with direct applications in agronomy and plant development. Rhizobium etli is a bacteria which provides legumes with ammonia (among other chemical compounds), thereby stimulating plant growth. A genome-scale approach, integrating the biochemical information available for R. etli, constitutes an...

Resendis-antonio, Osbaldo; Reed, Jennifer L.; Encarnacio?n, Sergio; Collado-vides, Julio; Palsson, Bernhard Ø.

2007-01-01

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Diversification of DNA Sequences in the Symbiotic Genome of Rhizobium etli  

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Bacteria of the genus Rhizobium and related genera establish nitrogen-fixing symbioses with the roots of leguminous plants. The genetic elements that participate in the symbiotic process are usually compartmentalized in the genome, either as independent replicons (symbiotic plasmids) or as symbiotic regions or islands in the chromosome. The complete nucleotide sequence of the symbiotic plasmid of Rhizobium etli model strain CFN42, symbiont of the common bean plant, has been reported. To bette...

Flores, Margarita; Morales, Lucia; Avila, Agusti?n; Gonza?lez, Vi?ctor; Bustos, Patricia; Garci?a, Delfino; Mora, Yolanda; Guo, Xianwu; Collado-vides, Julio; Pin?ero, Daniel; Da?vila, Guillermo; Mora, Jaime; Palacios, Rafael

2005-01-01

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Role of trehalose in heat and desiccation tolerance in the soil bacterium Rhizobium etli  

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Abstract Background The compatible solute trehalose is involved in the osmostress response of Rhizobium etli, the microsymbiont of Phaseolus vulgaris. In this work, we reconstructed trehalose metabolism in R. etli, and investigated its role in cellular adaptation and survival to heat and desiccation stress under free living conditions. Results Besides trehalose as major compatible solute, R. etli CE3 also accumulated glutamate and, if present in the medium, mannitol. Putative genes for trehal...

2012-01-01

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Inhibition of Rhizobium etli Polysaccharide Mutants by Phaseolus vulgaris Root Compounds  

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Crude bean root extracts of Phaseolus vulgaris were tested for inhibition of the growth of several polysaccharide mutants of Rhizobium etli biovar phaseoli CE3. Mutants deficient only in exopolysaccharide and some mutants deficient only in the O-antigen of the lipopolysaccharide were no more sensitive than the wild-type strain to the extracts, whereas mutants defective in both lipopolysaccharide and exopolysaccharide were much more sensitive. The inhibitory activity was found at much higher l...

Eisenschenk, Linda; Diebold, Ronald; Perez-lesher, Jeanett; Peterson, Andrew C.; Kent Peters, N.; Noel, K. Dale

1994-01-01

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Genetic Locus Required for Antigenic Maturation of Rhizobium etli CE3 Lipopolysaccharide  

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Rhizobium etli modifies lipopolysaccharide (LPS) structure in response to environmental signals, such as low pH and anthocyanins. These LPS modifications result in the loss of reactivity with certain monoclonal antibodies. The same antibodies fail to recognize previously isolated R. etli mutant strain CE367, even in the absence of such environmental cues. Chemical analysis of the LPS in strain CE367 demonstrated that it lacked the terminal sugar of the wild-type O antigen, 2,3,4-tri-O-methylf...

Duelli, Dominik M.; Tobin, Andrea; Box, Jodie M.; Kolli, V. S. Kumar; Carlson, Russell W.; Noel, K. Dale

2001-01-01

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Genomic lineages of Rhizobium etli revealed by the extent of nucleotide polymorphisms and low recombination  

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Full Text Available Abstract Background Most of the DNA variations found in bacterial species are in the form of single nucleotide polymorphisms (SNPs, but there is some debate regarding how much of this variation comes from mutation versus recombination. The nitrogen-fixing symbiotic bacteria Rhizobium etli is highly variable in both genomic structure and gene content. However, no previous report has provided a detailed genomic analysis of this variation at nucleotide level or the role of recombination in generating diversity in this bacterium. Here, we compared draft genomic sequences versus complete genomic sequences to obtain reliable measures of genetic diversity and then estimated the role of recombination in the generation of genomic diversity among Rhizobium etli. Results We identified high levels of DNA polymorphism in R. etli, and found that there was an average divergence of 4% to 6% among the tested strain pairs. DNA recombination events were estimated to affect 3% to 10% of the genomic sample analyzed. In most instances, the nucleotide diversity (? was greater in DNA segments with recombinant events than in non-recombinant segments. However, this degree of recombination was not sufficiently large to disrupt the congruence of the phylogenetic trees, and further evaluation of recombination in strains quartets indicated that the recombination levels in this species are proportionally low. Conclusion Our data suggest that R. etli is a species composed of separated lineages with low homologous recombination among the strains. Horizontal gene transfer, particularly via the symbiotic plasmid characteristic of this species, seems to play an important role in diversity but the lineages maintain their evolutionary cohesiveness.

González Víctor

2011-10-01

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Analysis of Rhizobium etli and of its symbiosis with wild Phaseolus vulgaris supports coevolution in centers of host diversification  

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Common beans (Phaseolus vulgaris) comprise three major geographic genetic pools, one in Mexico, Central America, and Colombia, another in the southern Andes, and a third in Ecuador and northern Peru. Species Rhizobium etli is the predominant rhizobia found symbiotically associated with beans in the Americas. We have found polymorphism in the common nodulation gene nodC among R. etli strains from a wide range of geographical origins, which disclosed three nodC types. The different nodC alleles...

Aguilar, O. Mario; Riva, Omar; Peltzer, Eitel

2004-01-01

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The extracellular proteome of Rhizobium etli CE3 in exponential and stationary growth phase  

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Abstract Background The extracellular proteome or secretome of symbiotic bacteria like Rhizobium etli is presumed to be a key element of their infection strategy and survival. Rhizobia infect the roots of leguminous plants and establish a mutually beneficial symbiosis. To find out the possible role of secreted proteins we analyzed the extracellular proteome of R. etli CE3 in the exponential and stationary growth phases in minimal medium, supplemented with su...

Meneses Niurka; Mendoza-Hernández Guillermo; Encarnación Sergio

2010-01-01

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The extracellular proteome of Rhizobium etli CE3 in exponential and stationary growth phase  

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Full Text Available Abstract Background The extracellular proteome or secretome of symbiotic bacteria like Rhizobium etli is presumed to be a key element of their infection strategy and survival. Rhizobia infect the roots of leguminous plants and establish a mutually beneficial symbiosis. To find out the possible role of secreted proteins we analyzed the extracellular proteome of R. etli CE3 in the exponential and stationary growth phases in minimal medium, supplemented with succinate-ammonium. Results The extracellular proteins were obtained by phenol extraction and identified by LC-ESI MS/MS. We identified 192 and 191 proteins for the exponential and stationary phases respectively. Using the software Signal P, we predicted signal peptides for 12.95% and 35.60% of the proteins identified in the exponential and stationary phases, respectively, which could therefore be secreted by the Sec pathway. For the exponential growth phase, we found in abundance proteins like the ribosomal proteins, toxins and proteins belonging to the group "defence mechanisms". For the stationary growth phase, we found that the most abundant proteins were those with unknown function, and in many of these we identified characteristic domains of proteases and peptidases. Conclusions Our study provided the first dataset of the secretome of R. etli and its modifications, which may lead to novel insights into the adaptive response of different stages of growth. In addition, we found a high number of proteins with unknown function; these proteins could be analyzed in future research to elucidate their role in the extracellular proteome of R. etli.

Mendoza-Hernández Guillermo

2010-10-01

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Insight into the carboxyl transferase domain mechanism of pyruvate carboxylase from Rhizobium etli.  

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The effects of mutations in the active site of the carboxyl transferase domain of Rhizobium etli pyruvate carboxylase have been determined for the forward reaction to form oxaloacetate, the reverse reaction to form MgATP, the oxamate-induced decarboxylation of oxaloacetate, the phosphorylation of MgADP by carbamoyl phosphate, and the bicarbonate-dependent ATPase reaction. Additional studies with these mutants examined the effect of pyruvate and oxamate on the reactions of the biotin carboxylase domain. From these mutagenic studies, putative roles for catalytically relevant active site residues were assigned and a more accurate description of the mechanism of the carboxyl transferase domain is presented. The T882A mutant showed no catalytic activity for reactions involving the carboxyl transferase domain but surprisingly showed 7- and 3.5-fold increases in activity, as compared to that of the wild-type enzyme, for the ADP phosphorylation and bicarbonate-dependent ATPase reactions, respectively. Furthermore, the partial inhibition of the T882A-catalyzed BC domain reactions by oxamate and pyruvate further supports the critical role of Thr882 in the proton transfer between biotin and pyruvate in the carboxyl transferase domain. The catalytic mechanism appears to involve the decarboxylation of carboxybiotin and removal of a proton from Thr882 by the resulting biotin enolate with either a concerted or subsequent transfer of a proton from pyruvate to Thr882. The resulting enolpyruvate then reacts with CO(2) to form oxaloacetate and complete the reaction. PMID:19341298

Zeczycki, Tonya N; St Maurice, Martin; Jitrapakdee, Sarawut; Wallace, John C; Attwood, Paul V; Cleland, W Wallace

2009-05-26

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Cloning and characterization of a thermostable xylitol dehydrogenase from Rhizobium etli CFN42  

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An NAD+-dependent xylitol dehydrogenase from Rhizobium etli CFN42 (ReXDH) was cloned and overexpressed in Escherichia coli. The DNA sequence analysis revealed an open reading frame of 1,044 bp, capable of encoding a polypeptide of 347 amino acid residues with a calculated molecular mass of 35,858 Da. The ReXDH protein was purified as an active soluble form using GST affinity chromatography. The molecular mass of the purified enzyme was estimated to be â?¼34 kDa by sodium dodecyl sulfateâ??polyacrylamide gel and â?¼135 kDa with gel filtration chromatography, suggesting that the enzyme is a homotetramer. Among various polyols, xylitol was the preferred substrate of ReXDH with a Km=17.9 mM and kcat/Km=0.5 mMâ??1 sâ??1 for xylitol. The enzyme had an optimal pH and temperature of 9.5 and 70 °C, respectively. Heat inactivation studies revealed a half life of the ReXDH at 40 °C of 120 min and a half denaturation temperature (T1/2) of 53.1 °C. ReXDH showed the highest optimum temperature and thermal stability among the known XDHs. Homology modeling and sequence analysis of ReXDH shed light on the factors contributing to the high thermostability of ReXDH. Although XDHs have been characterized from several other sources, ReXDH is distinguished from other XDHs by its high thermostability

Tiwari, Manish Kumar; Lee, Hee-Jung

2010-01-01

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Covalent immobilization of recombinant Rhizobium etli CFN42 xylitol dehydrogenase onto modified silica nanoparticles  

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Rare sugars have many applications in food industry, as well as pharmaceutical and nutrition industries. Xylitol dehydrogenase (XDH) can be used to synthesize various rare sugars enzymatically. However, the immobilization of XDH has not been performed to improve the industrial production of rare sugars. In this study, silica nanoparticles which have high immobilization efficiency were selected from among several carriers for immobilization of recombinant Rhizobium etli CFN42 xylitol dehydrogenase (ReXDH) and subjected to characterization. Among four different chemical modification methods to give different functional groups, the silica nanoparticle derivatized with epoxy groups showed the highest immobilization efficiency (92%). The thermostability of ReXDH was improved more than tenfold by immobilization on epoxy-silica nanoparticles; the t1/2 of the ReXDH was enhanced from 120 min to 1,410 min at 40 °C and from 30 min to 450 min at 50 °C. The Km of ReXDH was slightly altered from 17.9 to only 19.2 mM byimmobilization. The immobilized ReXDH had significant reusability, as it retained 81% activity after eight cycles of batch conversion of xylitol into L-xylulose. A�71% conversion and a productivity of 10.7 gh-1 l-1 were achieved when the immobilized ReXDH was employed to catalyze the biotransformation of xylitol to L-xylulose, a sugar that has been used in medicine and in the diagnosis of hepatitis. These results suggest that immobilization of ReXDH onto epoxy-silica nanoparticles has potential industrial application in rare sugar production.

Zhang, Ye-Wang; Tiwari, Manish Kumar

2011-01-01

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??????: Rhizobium indigoferae  

Full Text Available Bacteria Rhizobium/Agrobacterium group Rhizobium indigoferae Rhizobium indigoferae (scientific n am_microbe_ident2?taxonomy_id=158891 target=_blank>?? ????????? (??????): 1 ?????H15 (?????? - ?? ?????????): 1

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Genomic analysis of cyclic-di-GMP-related genes in rhizobial type strains and functional analysis in Rhizobium etli.  

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Rhizobia are soil bacteria that can fix nitrogen in symbiosis with leguminous plants or exist free living in the rhizosphere. Crucial to their complex lifestyle is the ability to sense and respond to diverse environmental stimuli, requiring elaborate signaling pathways. In the majority of bacteria, the nucleotide-based second messenger cyclic diguanosine monophosphate (c-di-GMP) is involved in signal transduction. Surprisingly, little is known about the importance of c-di-GMP signaling in rhizobia. We have analyzed the genome sequences of six well-studied type species (Bradyrhizobium japonicum, Mesorhizobium loti, Rhizobium etli, Rhizobium leguminosarum, Sinorhizobium fredii, and Sinorhizobium meliloti) for proteins possibly involved in c-di-GMP signaling based on the presence of four domains: GGDEF (diguanylate cyclase), EAL and HD-GYP (phosphodiesterase), and PilZ (c-di-GMP sensor). We find that rhizobia possess a high number of these proteins. Conservation analysis suggests that c-di-GMP signaling proteins modulate species-specific pathways rather than ancient rhizobia-specific processes. Two hybrid GGDEF-EAL proteins were selected for functional analysis, R. etli RHE_PD00105 (CdgA) and RHE_PD00137 (CdgB). Expression of cdgA and cdgB is repressed by the alarmone (p)ppGpp. cdgB is significantly expressed on plant roots and free living. Mutation of cdgA, cdgB, or both does not affect plant root colonization, nitrogen fixation capacity, biofilm formation, motility, and exopolysaccharide production. However, heterologous expression of the individual GGDEF and EAL domains of each protein in Escherichia coli strongly suggests that CdgA and CdgB are bifunctional proteins, possessing both diguanylate cyclase and phosphodiesterase activities. Taken together, our results provide a platform for future studies of c-di-GMP signaling in rhizobia. PMID:24728599

Gao, Shanjun; Romdhane, Samir Ben; Beullens, Serge; Kaever, Volkhard; Lambrichts, Ivo; Fauvart, Maarten; Michiels, Jan

2014-05-01

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A type III polyketide synthase from Rhizobium etli condenses malonyl CoAs to a heptaketide pyrone with unusually high catalytic efficiency  

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A novel type III polyketide synthase (RePKS) from Rhizobium etli produced a heptaketide pyrone using acetyl-CoA and six molecules of malonyl-CoA. Its catalytic efficiency (k(cat)/K-m = 5230 mM(-1) min(-1)) for malonyl CoA was found to be the highest ever reported. Molecular dynamics studies revealed the unique features of RePKS.

Jeya, Marimuthu; Kim, Tae-Su

2012-01-01

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Probing the catalytic roles of Arg548 and Gln552 in the carboxyl transferase domain of the Rhizobium etli pyruvate carboxylase by site-directed mutagenesis.  

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The roles of Arg548 and Gln552 residues in the active site of the carboxyl transferase domain of Rhizobium etli pyruvate carboxylase were investigated using site-directed mutagenesis. Mutation of Arg548 to alanine or glutamine resulted in the destabilization of the quaternary structure of the enzyme, suggesting that this residue has a structural role. Mutations R548K, Q552N, and Q552A resulted in a loss of the ability to catalyze pyruvate carboxylation, biotin-dependent decarboxylation of oxaloacetate, and the exchange of protons between pyruvate and water. These mutants retained the ability to catalyze reactions that occur at the active site of the biotin carboxylase domain, i.e., bicarbonate-dependent ATP cleavage and ADP phosphorylation by carbamoyl phosphate. The effects of oxamate on the catalysis in the biotin carboxylase domain by the R548K and Q552N mutants were similar to those on the catalysis of reactions by the wild-type enzyme. However, the presence of oxamate had no effect on the reactions catalyzed by the Q552A mutant. We propose that Arg548 and Gln552 facilitate the binding of pyruvate and the subsequent transfer of protons between pyruvate and biotin in the partial reaction catalyzed in the active site of the carboxyl transferase domain of Rhizobium etli pyruvate carboxylase. PMID:20230056

Duangpan, Saowapa; Jitrapakdee, Sarawut; Adina-Zada, Abdussalam; Byrne, Lindsay; Zeczycki, Tonya N; St Maurice, Martin; Cleland, W Wallace; Wallace, John C; Attwood, Paul V

2010-04-20

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Genetics and Biochemistry of Rhizobium Meliloti Acidic Extracellular Heteropolysaccharide and Its Role in Nodulation: Final Technical Report.  

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We have been working with two polysaccharides secreted by Rhizobium meliloti that promote nodule invasion, succinoglycan and EPSb. R. meliloti mutants in succinoglycan synthesis are designated Exo-, and fail to invade alfalfa root nodules. Multiple forms ...

J. A. Leigh

1989-01-01

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Visualization of highly dynamic F-actin plus ends in growing phaseolus vulgaris root hair cells and their responses to Rhizobium etli nod factors.  

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Legume plants secrete signaling molecules called flavonoids into the rhizosphere. These molecules activate the transcription of rhizobial nod genes, which encode proteins involved in the synthesis of signaling compounds named Nod factors (NFs). NFs, in turn, trigger changes in plant gene expression, cortical cell dedifferentiation and mitosis, depolarization of the root hair cell membrane potential and rearrangement of the actin cytoskeleton. Actin polymerization plays an important role in apical growth in hyphae and pollen tubes. Using sublethal concentrations of fluorescently labeled cytochalasin D (Cyt-Fl), we visualized the distribution of filamentous actin (F-actin) plus ends in living Phaseolus vulgaris and Arabidopsis root hairs during apical growth. We demonstrated that Cyt-Fl specifically labeled the newly available plus ends of actin microfilaments, which probably represent sites of polymerization. The addition of unlabeled competing cytochalasin reduced the signal, suggesting that the labeled and unlabeled forms of the drug bind to the same site on F-actin. Exposure to Rhizobium etli NFs resulted in a rapid increase in the number of F-actin plus ends in P. vulgaris root hairs and in the re-localization of F-actin plus ends to infection thread initiation sites. These data suggest that NFs promote the formation of F-actin plus ends, which results in actin cytoskeleton rearrangements that facilitate infection thread formation. PMID:24399235

Zepeda, Isaac; Sánchez-López, Rosana; Kunkel, Joseph G; Bañuelos, Luis A; Hernández-Barrera, Alejandra; Sánchez, Federico; Quinto, Carmen; Cárdenas, Luis

2014-03-01

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Effets de la double symbiose Rhizobium TAL 1147-Glomus clarum sur la croissance et la nodulation de Racosperma auriculiforme en République Démocratique du Congo  

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Full Text Available Effects of Inoculation with Rhizobium TAL 1147'-Glomus Clarum in a Nursery on Racosperma Auriculiforme Growth and Nodulation in Democratie Republic of Congo. The efficiency evaluation of five vesicular-arbuscular mycorrhiza spp. revealed that the mycobiont Glomus clarum is suitable for the mycorrhizogene replanting of the Kinzono grassy savanna. This present study reports results of effects of its inoculation at the same time that the Rhizobium TAL 1147 in nursery on Racosperma auriculiforme growth and nodulation in this same savanna's soil. Compared to the individual inoculation (Glomus clarum or Rhizobium TAL 1147 and to the uninoculated control, the dual inoculation Rhizobium TAL 1147-Glomus clarum has improved significantly (P <0.01 the growth and the nodulation of this legume tree five months after the sowing. A such inoculation can be recommended for an effective implantation at large-scale of this specie in poor Kinzono soil in nitrogen and in soluble phosphore.

Bulakali, B.

1999-01-01

 
 
 
 
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Enhanced nitrogen fixation in a Rhizobium etli ntrC mutant that overproduces the Bradyrhizobium japonicum symbiotic terminal oxidase cbb{sub 3}  

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The ntrC gene codes for a transcriptional activator protein that modulates gene expression in response to nitrogen. The cytochrome production pattern of a Rhizobium etli ntrC mutant (CFN2012) was studied. CO difference spectral analysis of membranes showed that CFN2012 produced a terminal oxidase similar to the symbiotic terminal oxidase of bacteroids in free-living cells under aerobic conditions, with a characteristic trough at 553 nm. CFN2012 produced two c-type cytochromes with molecular masses of 27 and 32 kDa in contrast with the wild-type strain, which produced only a 32-kDa c-tye cytochrome. The expression levels of the R. etli fix/NOQP operon, which codes for terminal oxidase cbb{sub 3}, were not affected by the ntrC mutation. However, the production levels of the two c-type cytochromes (27 and 32 kDa) were enhanced at least eightfold when the Bradyrhizobium japonicum fixNOQP operon was expressed in CFN2012 from the nptII promoter (pMSfix{sup c}), suggesting that these proteins are subunits FixO (27 kDa) and FixP (32 kDa) of cbb{sub 3} and that CFN2012/pMSfix{sup c} overproduced this terminal oxidase. CFN2012/pMSfix{sup c} showed a significant increase in its symbiotic performance as judged by the determination of nitrogenase activities of plants inoculated with this strain, suggesting that the overproduction of cbb{sub 3} terminal oxidase correlates with an enhancement in symbiotic nitrogen fixation.

Soberon, M.; Lopez, O.; Morera, C.; Girard, M.L.; Tabche, M.L.; Miranda, J. [Univ. Nacional Autonoma de Mexico, Cuernavaca (Mexico)

1999-05-01

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Elucidation of a novel lipid A ?-(1,1)-GalA transferase gene (rgtF) from Mesorhizobium loti: Heterologous expression of rgtF causes Rhizobium etli to synthesize lipid A with ?-(1,1)-GalA.  

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An unusual ?-(1,1)-galacturonic acid (GalA) lipid A modification has been reported in the lipopolysaccharide of a number of interesting Gram-negative bacteria, including the nitrogen-fixing bacteria Azospirillum lipoferum, Mesorhizobium huakuii and M. loti, the stalk-forming bacterium Caulobacter crescentus and the hyperthermophilic bacterium Aquifex aeolicus. However, the ?-(1,1)-GalA transferase (GalAT) gene, which we have named RgtF, was not identified. Species of the Rhizobium genera produce lipid A with ?-(1,4')-GalA but not ?-(1,1)-GalA. The Rhizobium GalAT, RgtD, is the lipid A ?-(1-4')-GalAT which utilizes the lipid donor dodecaprenyl-phosphate GalA (Dod-P-GalA) for GalA transfer. An additional Rhizobium GalAT, RgtE, is required for the biosynthesis of Dod-P-GalA. We predicted candidate rgtF genes in bacterial species known to produce lipid A with ?-(1,1)-GalA. In order to determine the predicted rgtF gene function, we cloned the M. loti rgtF gene into an expression plasmid and introduced that plasmid into Rhizobium etli strains that do not contain the rgtF gene nor produce lipid A ?-(1,1)-GalA. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis combined with NMR studies revealed that the lipid As from these rgtF-complemented strains were modified with an additional ?-(1,1)-GalA attached to the proximal glucosamine. PMID:23283001

Brown, Dusty B; Muszynski, Artur; Carlson, Russell W

2013-05-01

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CYCLOPS: a new vision on rhizobium-induced nodule organogenesis.  

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The accommodation of nitrogen-fixing rhizobium bacteria inside plant cells requires reprogramming of root cortex cells by rhizobial signals. In this issue of Cell Host & Microbe, Singh et al. (2014) reveal that CYCLOPS, representing a novel class of transcription factors, links rhizobium-induced calcium signaling to reprogramming of root cortex cells. PMID:24528858

Limpens, Erik; Bisseling, Ton

2014-02-12

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Effets de la double symbiose Rhizobium-Glomus spp. sur la croissance de Leucaena leucocephala (Lam. de Wit en pépinière, et dix mois après transplantation au Zaïre  

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Full Text Available Effects of dual inoculation with Rhizobium and Glomus spp. on the growth of Leucaena leucocephala (Lam. de Wit in the nursery, and ten months after outplanting in Zaire. This work underlines the utility to inoculate in the nursery Leucaena leucocephala (Lam. de Wit, with efficient strains of Rhizobium and endomycorrhizal fungi, in order to ensure good initial plant growth after outplanting. In general, soil fumigation in the nursery allowed growth enhancement of control plants and the best effect of biofertilizers was obtained in the nursery and ten months after outplanting. Glomus vesiculiferum (Thaxter Gerdemann and Trappe associated or not with Rhizobium TAL 1145 likely produced the same effect by using natural soil in the nursery.

Bulakali, B.

1992-01-01

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Near-full length sequencing of 16S rDNA and RFLP indicates that Rhizobium etli is the dominant species nodulating Egyptian winter Berseem clover (Trifolium alexandrinum L.).  

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Egyptian winter Berseem clover (EWBC) is one of the main important forage legume crops in Egypt that is used for animal feeding in winter and it occupies about 2.5 million feddans (Feddan=4200m(2)) in winter agricultural rotation systems. Forty-eight rhizobial isolates that nodulated this legume host from different geographical regions within Egypt were isolated. RFLP analyses of 16S rDNA (1.5kb) and whole ribosomal DNA (5kb), the sequencing of 16S rDNA, and the sequencing of nodC, nifH and house keeping genes were used to identify these isolates. The RFLP analysis of 16S rDNA (1.5kb) among 15 representative strains with three enzymes generated two genotypes. The largest genotype was similar to Rhizobium etli CFN42T (93.33%) except for strain 902 that failed to re-nodulate EWBC. RFLP analysis of complete ribosomal DNA (5kb) produced five genotypes. The majority of tested strains shared the genotype with R. etli CFN42T (53.33%). Only one strain (1002) shared the genotype with Rhizobium leguminosarum sv. trifolii 3023. The other four strains were comprised of two unique genotypes. Phylogenetic analysis of 16S rDNA sequences revealed that seven representative strains could be divided into two genetic clusters sharing the ancestral clad with R. etli CFN42T. A phylogenetic tree based on nodC gene sequence confirmed that all the examined strains shared the genetic lineage with R. leguminosarum sv. trifolii WSM1325. The phylogenetic trees of house keeping genes are supported strongly the identification of majority of strains as a novel symbiovar of R. etli with new lineages. PMID:24054695

Shamseldin, Abdelaal; Moawad, Hassan; Abd El-Rahim, Wafaa M; Sadowsky, Michael J

2014-03-01

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Denitrification by Rhizobium meliloti.  

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Rhizobium meliloti strains were investigated for their denitrification activity as free-living cells and in nodules on lucerne (Medicago sativa) roots. They were also investigated for presence of nitrous oxide reductase (nos) activity and for genes using ...

A. Rosen

1996-01-01

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Improvement of Rhizobium Inoculants  

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A practical approach was used to develop a Rhizobium (Bradyrhizobium) japonicum inoculant that increases soybean (Glycine max (L.) Merr.) yield in fields with indigenous Rhizobium populations, which typically outcompete strains present in existing commercial inoculants and therefore decrease the value of inoculant use. Field tests managed by several universities in the Mississippi delta region averaged a 169-kg/ha (P < 0.01) grain yield increase. The inoculant contains a mixture of mutants se...

Paau, Alan S.

1989-01-01

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Effets de la fertilisation azotée, de l'inoculation par Rhizobium sp. et du régime des pluies sur la production de la biomasse et la teneur en azote du pois chiche  

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Full Text Available Effect of nitrogen fertilization, inoculation with Rhizobium sp. and precipitation on the biomass production and nitrogen content of chickpea. Water availability and soil fertility (especially soil N content are the major factors affecting chickpea yield in Mediterranean regions, characterized by low rainfall, poorly distributed and rapid mineralization of organic matter. In order to study the effect of N-fertilization and inoculation with Rhizobium on chickpea biomass production and N-content, field experiment were carried out at two stations of INRAT in northern Tunisia during two consecutive years, 2000-2001 and 2001-2002. Results showed that N-fertilization significantly increased shoot biomass and N-content while decreasing nodule mass. Inoculation with both the two Rhizobium strains resulted in nodule mass increase but the shoot N-content was not significantly affected. Regardless of the stations and treatments, rainfall decrease between the two years of the experiment significantly reduced shoot and root biomass while improving nodulation, especially at Oued Beja. However, the nodule developed under water deficit conditions was correlated with a very high decrease of the nitrogen fixed. Nevertheless, the mineral nitrogen apply in soil improved the N-content of aerial parts in the two stations, especially in waterless season.

Lachaâl M.

2009-01-01

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Determinants of nodulation competitiveness in Rhizobium etli. Final report for period September 30, 1996-September 29, 1999.  

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Nitrogen is a major limiting nutrient in crop production. Chemical fertilizers, which are used extensively to meet crop nitrogen requirements, contribute to the high energy inputs of modern agriculture and cause human health and environmental problems. Le...

J. Handelsman

2000-01-01

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Genome-wide detection of predicted non-coding RNAs in Rhizobium etli expressed during free-living and host-associated growth using a high-resolution tiling array  

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Full Text Available Abstract Background Non-coding RNAs (ncRNAs play a crucial role in the intricate regulation of bacterial gene expression, allowing bacteria to quickly adapt to changing environments. In the past few years, a growing number of regulatory RNA elements have been predicted by computational methods, mostly in well-studied ?-proteobacteria but lately in several ?-proteobacteria as well. Here, we have compared an extensive compilation of these non-coding RNA predictions to intergenic expression data of a whole-genome high-resolution tiling array in the soil-dwelling ?-proteobacterium Rhizobium etli. Results Expression of 89 candidate ncRNAs was detected, both on the chromosome and on the six megaplasmids encompassing the R. etli genome. Of these, 11 correspond to functionally well characterized ncRNAs, 12 were previously identified in other ?-proteobacteria but are as yet uncharacterized and 66 were computationally predicted earlier but had not been experimentally identified and were therefore classified as novel ncRNAs. The latter comprise 17 putative sRNAs and 49 putative cis-regulatory ncRNAs. A selection of these candidate ncRNAs was validated by RT-qPCR, Northern blotting and 5' RACE, confirming the existence of 4 ncRNAs. Interestingly, individual transcript levels of numerous ncRNAs varied during free-living growth and during interaction with the eukaryotic host plant, pointing to possible ncRNA-dependent regulation of these specialized processes. Conclusions Our data support the practical value of previous ncRNA prediction algorithms and significantly expand the list of candidate ncRNAs encoded in the intergenic regions of R. etli and, by extension, of ?-proteobacteria. Moreover, we show high-resolution tiling arrays to be suitable tools for studying intergenic ncRNA transcription profiles across the genome. The differential expression levels of some of these ncRNAs may indicate a role in adaptation to changing environmental conditions.

Thijs Inge M

2010-01-01

31

Diversity of rhizobia from nodules of the leguminous tree Gliricidia sepium, a natural host of Rhizobium tropici.  

Science.gov (United States)

The Rhizobium species that nodulate the legume tree Gliricidia sepium were analyzed by phenotypic characteristics (including nodule formation in different hosts), PCR-RFLP patterns and sequences of 16S rRNA genes, multilocus enzyme electrophoresis, and plasmid patterns. Strains of Rhizobium tropici type A and B, Sinorhizobium spp., and Rhizobium etli bv. phaseoli were encountered in G. sepium nodules and their presence depended on the site sampled. PMID:12115061

Acosta-Durán, Carlos; Martínez-Romero, Esperanza

2002-08-01

32

Genomic instability in Rhizobium phaseoli.  

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Experience from different laboratories indicates that Rhizobium strains can generate variability in regard to some phenotypic characteristics such as colony morphology or symbiotic properties. On the other hand, several reports suggest that under certain stress conditions or genetic manipulations Rhizobium cells can present genomic rearrangements. In search of frequent genomic rearrangements, we analyzed three Rhizobium strains under laboratory conditions that are not considered to cause stre...

Flores, M.; Gonza?lez, V.; Pardo, M. A.; Leija, A.; Marti?nez, E.; Romero, D.; Pin?ero, D.; Da?vila, G.; Palacios, R.

1988-01-01

33

Phosphate solubilization by Rhizobium strains.  

Science.gov (United States)

Forty-six Rhizobium isolates from legume root and stem nodules were examined for their phosphate-solubilizing ability on Pikovskaya's agar medium. Rhizobium isolates from root nodules of Cassia absus, Vigna trilobata and three strains from Sesbania sesban showed zone of tricalcium phosphate (TCP) solubilization. The isolate from C. absus showed maximum solubilization (620 ?g/ml) after 12 d of incubation, while the Rhizobium sp. strain 26 (from S. sesban) showed the least amount (150 ?g/ml) of phosphate solubilization. Among the carbon sources tested for their ability to solubilize TCP, maximum solubilization (620 ?g/ml) was observed in glucose by Rhizobium isolate from C. absus. Phosphate solubilization increased with increase in glucose concentration steeply up to 2% and slowly above this concentration in four isolates. Among the nitrogen sources tested, maximum solubilization (620 ?g/ml) was observed in ammonium sulphate by Rhizobium isolate from C. absus. PMID:23100757

Sridevi, M; Mallaiah, K V

2009-03-01

34

Phylogenetic relationships and host range of Rhizobium spp. that nodulate Phaseolus vulgaris L.  

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We determined the nucleotide sequences of 16S rRNA gene segments from five Rhizobium strains that have been isolated from tropical legume species. All share the capacity to nodulate Phaseolus vulgaris L., the common bean. Phylogenetic analysis confirmed that these strains are of two different chromosomal lineages. We defined the host ranges of two strains of Rhizobium etli and three strains of R. tropici, comparing them with those of the two most divergently related new strains. Twenty-two of...

1995-01-01

35

Oligo- and polysaccharide synthesis by Rhizobium leguminosarum and Rhizobium meliloti.  

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Rhizobium and Agrobacterium species are capable of synthesizing a variety of extracellular and cellular oligo- and polysaccharides. Changes in environmental conditions may all affect the composition, physical properties, and relative amounts of oligo- and polysaccharides. Interest in the field of Rhizobium polys accharides has resulted from a development in two distinct areas, (i) the role of oligo- and polysaccharides in the microbe- plant interaction, and (ii) studies on the physico- chemic...

1992-01-01

36

Beltsville 'Rhizobium' Culture Collection Catalog.  

Science.gov (United States)

The USDA Beltsville Rhizobium Culture Collection contains a wide array of root nodule bacteria that fix nitrogen in symbiosis with legumes. The catalog gives information on the collection holdings and the services provided by the staff. Strains in the col...

H. H. Keyser R. F. Griffin

1987-01-01

37

Tryptophan auxotrophs of Rhizobium japonicum.  

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Eleven tryptophan-requiring mutants of Rhizobium japonicum I-110 ARS were isolated after nitrous acid mutagenesis and fell into five groups based on characterization by supplementation with intermediates and enzyme assays.

Wells, S. E.; Kuykendall, L. D.

1983-01-01

38

Physiology of the Rhizobium-legume association  

International Nuclear Information System (INIS)

Rhizobium deoxyribonucleic acid has been detected within Vicia faba root cells by in situ hybridization and autoradiography after exposure of root apexes to Rhizobium viable cells. Reannealed regions are localized in the cortex cells; the presence of bacterial DNA is specific for the root tissue; labelled regions were not detectable within apexes exposed to non-nodulating strains or to bacteria other than Rhizobium; Rhizobium DNA was not detectable in tissues of plants other than its leguminous host

1976-01-01

39

En route vers la nano stabilisation de CLIC faisceau principale et focalisation finale  

CERN Multimedia

Pour atteindre la luminosité voulue de CLIC, la taille transversale du faisceau doit être de l?ordre du nanomètre. Ceci nécessite une stabilité vibratoire des quadripôles du faisceau principal de 1 nm et même 0.1 nm pour les doublets de la focalisation finale. La nano technologie et la nano stabilisation sont des activités qui évoluent rapidement dans l?industrie et centres de recherche pour des applications très variées comme l?électronique, l?optique, la chimie voire la médecine. Cette présentation décrit les avancées techniques nécessaires pour atteindre l?objectif de CLIC et les projets et collaborations R&D prévus pour démontrer la faisabilité de la nano stabilisation de CLIC en 2010.

Artoos, K; Guinchard, M; Hauviller, Claude; Lackner, F; CERN. Geneva. TS Department

2008-01-01

40

75 FR 60820 - United States v. Adobe Systems, Inc., et al.; Proposed Final Judgment and Competitive Impact...  

Science.gov (United States)

...JUSTICE Antitrust Division United States v. Adobe Systems, Inc., et al.; Proposed Final...Columbia in United States of America v. Adobe Systems, Inc., et al., Civil Case...States filed a Complaint alleging that Adobe Systems, Inc., Apple Inc.,...

2010-10-01

 
 
 
 
41

The celC gene, a new phylogenetic marker useful for taxonomic studies in Rhizobium.  

Science.gov (United States)

The celC gene codifies for a cellulase that fulfils a very significant role in the infection process of clover by Rhizobium leguminosarum. This gene is located in the celABC operon present in the chromosome of strains representing R. leguminosarum, Rhizobium etli and Rhizobium radiobacter whose genomes have been completely sequenced. Nevertheless, the existence of this gene in other species of the genus Rhizobium had not been investigated to date. In this study, the celC gene was analysed for the first time in several species of this genus isolated from legume nodules and plant tumours, in order to compare the celC phylogeny to those of other chromosomal and plasmidic genes. The results obtained showed that phylogenies of celC and chromosomal genes, such as rrs, recA and atpD, were completely congruent, whereas no relation was found with symbiotic or virulence genes. Therefore, the suitability and usefulness of the celC gene to differentiate species of the genus Rhizobium, especially those with closely related rrs genes, was highlighted. Consequently, the taxonomic status of several strains of the genus Rhizobium with completely sequenced genomes is also discussed. PMID:21621937

Robledo, Marta; Velázquez, Encarna; Ramírez-Bahena, Martha Helena; García-Fraile, Paula; Pérez-Alonso, Ana; Rivas, Raúl; Martínez-Molina, Eustoquio; Mateos, Pedro F

2011-09-01

42

Analysis of cellular fatty acids and phenotypic relationships of Agrobacterium, Bradyrhizobium, Mesorhizobium, Rhizobium and Sinorhizobium species using the Sherlock Microbial Identification System.  

Science.gov (United States)

Previous studies have demonstrated that cellular fatty acid analysis is a useful tool for identifying unknown strains of rhizobia and establishing taxonomic relationships between the species. In this study, the fatty acid profiles of over 600 strains belonging to the genera Agrobacterium, Bradyrhizobium, Mesorhizobium, Rhizobium and Sinorhizobium were evaluated using the gaschromatography-based Sherlock Microbial Identification System (MIS). Data collected with the MIS showed that the three phylogenetically defined biovars of the genus Agrobacterium formed discrete clusters, whilst species belonging to the genus Mesorhizobium formed three subclusters which were easily distinguished. These three subclusters contained Mesorhizobium ciceri and Mesorhizobium mediterraneum, Mesorhizobium tianshanense fatty acid group I and Mesorhizobium plurifarium, and Mesorhizobium huakuii and Mesorhizobium loti. The genus Sinorhizobium was composed of an individual position for Sinorhizobium meliloti and a large cluster comprising Sinorhizobium fredii, Sinorhizobium saheli, Sinorhizobium terangae, Sinorhizobium kostiense and Sinorhizobium arboris. S. meliloti contained significantly higher levels of the fatty acid 19:0 cyclo omega 8 cis and clustered with Rhizobium sp. (Hedysarum coronarium). However, discrimination between the species of genera Sinorhizobium and Rhizobium was a function of the concentration of 16:0 3-OH. The genus Rhizobium contained a single cluster containing Rhizobium sp. (Hedysarum coronarium), Rhizobium gallicum, Rhizobium leguminosarum and Rhizobium etli, along with individual positions for Rhizobium giardinii, Rhizobium tropici, Rhizobium galegae and Rhizobium hainanense. R. tropici and R. hainanense exhibited similarity to Agrobacterium biovar 2, whilst R. galegae was similar to Agrobacterium biovar 1. R. giardinii appeared unique, with comparatively little similarity to the other species. Analysis of the genus Bradyrhizobium revealed large differences from the other genera studied. Two subgroups of Bradyrhizobium elkanii were detected and easily distinguished from Bradyrhizobium japonicum. Bradyrhizobium liaoningense and Bradyrhizobium sp. (Arachis hypogaea), a group isolated from Chinese peanut plants, showed similarities to B. japonicum, whilst a subgroup of M. tianshanense appeared identical to Bradyrhizobium sp. (Arachis hypogaea). PMID:10758890

Tighe, S W; de Lajudie, P; Dipietro, K; Lindström, K; Nick, G; Jarvis, B D

2000-03-01

43

Infection of soybean and pea nodules by Rhizobium spp. purine auxotrophs in the presence of 5-aminoimidazole-4-carboxamide riboside.  

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Purine auxotrophs of various Rhizobium species are symbiotically defective, usually unable to initiate or complete the infection process. Earlier studies demonstrated that, in the Rhizobium etli-bean symbiosis, infection by purine auxotrophs is partially restored by supplementation of the plant medium with 5-amino-imidazole-4-carboxamide (AICA) riboside, the unphosphorylated form of the purine biosynthetic intermediate AICAR. The addition of purine to the root environment does not have this e...

1994-01-01

44

Denitrification by Rhizobium meliloti  

Energy Technology Data Exchange (ETDEWEB)

Rhizobium meliloti strains were investigated for their denitrification activity as free-living cells and in nodules on lucerne (Medicago sativa) roots. They were also investigated for presence of nitrous oxide reductase (nos) activity and for genes using a nosZ probe derived from the Pseudomonas stutzeri. To decide whether R. meliloti strains used as inoculants contribute to the total denitrification activity in a lucerne ley, strains with different denitrifying capacities were used in field and laboratory experiments. The nitrate reduction activity of R. meliloti during anaerobic respiration was compared with that of a strain of Pseudomonas aeruginosa. A great diversity in the denitrification activity was found within strains of R. meliloti, and four of thirteen investigated strains showed an obvious denitrification activity. Two denitrifying bacteria were used as references, one strain each of Bradyrhizobium japonicum and P. aeruginosa. All but one of the R. meliloti strains hybridized to the PstI-fragment of the nosZ-gene from P. stutzeri. Two sizes of the hybridizing fragment, 5 and 7 kb, were noticed. Nos activity was only shown in three R. meliloti strains, and these were all characterized by a high denitrification activity. The potential denitrification activity was about 20, 40, and 80 times higher than the actual denitrification activity for lucerne, fallow, and grass, respectively. The potential denitrification activity was almost the same in lucerne and grass planted soils. Compared with the unplanted soil, the presence of lucerne roots in the soil increased the actual denitrification activity, while roots of both plant species, grass and lucerne, increased the potential denitrification activity in the soil. 32 refs, 7 figs, 1 tab

Rosen, A.

1996-10-01

45

An Outer Membrane Enzyme That Generates the 2-Amino-2-deoxy-gluconate Moiety of Rhizobium leguminosarum Lipid A*S  

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The structures of Rhizobium leguminosarum and Rhizobium etli lipid A are distinct from those found in other Gram-negative bacteria. Whereas the more typical Escherichia coli lipid A is a hexa-acylated disaccharide of glucosamine that is phosphorylated at positions 1 and 4?, R. etli and R. leguminosarum lipid A consists of a mixture of structurally related species (designated A–E) that lack phosphate. A conserved distal unit, comprised of a diacylated glucosamine moiety with galacturonic a...

2003-01-01

46

Peritonitis due to Rhizobium radiobacter  

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Full Text Available Rhizobium radiobacter (Agrobacterium radiobacter is an aerobicGram-negative rod belonging to Agrobacterium genus, a groupof phytopathogenic bacteria present in the soil that has beenimplicated in human opportunistic infections. We report a clinicalcase of bacterial peritonitis in a 5-year-old child with chronic renaldisease in peritoneal dialysis, who had a history of direct soilcontact identified. The infection was treated with ceftazidime andpiperaciline+tazobactam without relapses or the need to remove theperitoneal dialysis catheter.

Raquel Marta

2011-09-01

47

Melanin Production by Rhizobium Strains  

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Different Rhizobium and Bradyrhizobium strains were screened for their ability to produce melanin. Pigment producers (Mel+) were found among strains of R. leguminosarum biovars viceae, trifolii, and phaseoli, R. meliloti, and R. fredii; none of 19 Bradyrhizobium strains examined gave a positive response. Melanin production and nod genes were plasmid borne in R. leguminosarum biovar trifolii RS24. In R. leguminosarum biovar phaseoli CFN42 and R. meliloti GR015, mel genes were located in the re...

Cubo, M. Teresa; Buendia-claveria, Ana M.; Beringer, John E.; Ruiz-sainz, Jose? E.

1988-01-01

48

Search for W' in Lepton+Missing ET Final State With Early Data at ATLAS  

CERN Document Server

Extensions of the Standard Model gauge symmetries imply the existence of new heavy charged gauge boson generically denoted as W'. Assuming its Standard Model-like couplings to fermions, we evaluate the ATLAS discovery potential of such a boson in lepton (electron and muon) plus Missing ET final state.The whole study is based on the full detector simulation data which include trigger performance and realistic detector calibration.Relevant systematic uncertainties are addressed. The study is focused at early stages of data taking with center of mass energy of sqrt(s)=14 TeV.

Vranjes, N

2008-01-01

49

Analysis of the Rhizobium Meliloti Surface.  

Science.gov (United States)

The authors have identified a number of genes in Rhizobium meliloti that affect outer membrane lipopolysaccharides (LPS). These include three genes defined by mutants with different patterns of resistance to a panel of bacteriophages, of which Class 2 and...

E. R. Signer

1988-01-01

50

Effectiveness of Rhizobium Under Salinity Stress  

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This research work was conducted to evaluate the efficacy of Rhizobium trifolii in enhancing the salt tolerance of Trifolium alexandrinum (Berseem or Egyptian clover), protein value of fodder and nitrogen fixation in the soil. Three salinity levels (8,12, 16 dS m-1) were developed in a loamy soil in pots. A similar set of inoculated pots with Rhizobium trifolii was also arranged. Berseem crop was grown in both of the sets. The data indicated that total g...

Nazir Hussain; Fakhar Mujeeb; Tahir, M.; Khan, G. D.; Hassan, N. M.; Abdul Bari

2002-01-01

51

Evolutionary origin of rhizobium Nod factor signaling  

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For over two decades now, it is known that the nodule symbiosis between legume plants and nitrogen fixing rhizobium bacteria is set in motion by the bacterial signal molecule named nodulation (Nod) factor.1 Upon Nod factor perception a signaling cascade is activated that is also essential for endomycorrhizal symbiosis (Fig. 1). This suggests that rhizobium co-opted the evolutionary far more ancient mycorrhizal signaling pathway in order to establish an endosymbiotic interaction with legumes.2...

Streng, A.; Camp, R.; Bisseling, T.; Geurts, R.

2011-01-01

52

Effect of Plasmid pIJ1008 from Rhizobium leguminosarum on Symbiotic Function of Rhizobium meliloti  

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Plasmid pIJ1008, which carries determinants for uptake hydrogenase (Hup) activity, was transferred from Rhizobium leguminosarum to Rhizobium meliloti without impairing the capacity of the latter species to form root nodules on alfalfa. The plasmid was still present in rhizobia reisolated from the root nodules of 12 different alfalfa cultivars, but only low levels of Hup activity were detected in alfalfa.

Bedmar, E. J.; Brewin, N. J.; Phillips, D. A.

1984-01-01

53

Reclassification of Rhizobium tropici type A strains as Rhizobium leucaenae sp. nov.  

Science.gov (United States)

Rhizobium tropici is a well-studied legume symbiont characterized by high genetic stability of the symbiotic plasmid and tolerance to tropical environmental stresses such as high temperature and low soil pH. However, high phenetic and genetic variabilities among R. tropici strains have been largely reported, with two subgroups, designated type A and B, already defined within the species. A polyphasic study comprising multilocus sequence analysis, phenotypic and genotypic characterizations, including DNA-DNA hybridization, strongly supported the reclassification of R. tropici type A strains as a novel species. Type A strains formed a well-differentiated clade that grouped with R. tropici, Rhizobium multihospitium, Rhizobium miluonense, Rhizobium lusitanum and Rhizobium rhizogenes in the phylogenies of the 16S rRNA, recA, gltA, rpoA, glnII and rpoB genes. Several phenotypic traits differentiated type A strains from all related taxa. The novel species, for which the name Rhizobium leucaenae sp. nov. is proposed, is a broad host range rhizobium being able to establish effective root-nodule symbioses with Leucaena leucocephala, Leucaena esculenta, common beans (Phaseolus vulgaris) and Gliricidia sepium. Strain CFN 299(T) (?=?USDA 9039(T)?=?LMG 9517(T)?=?CECT 4844(T)?=?JCM 21088(T)?=?IAM 14230(T)?=?SEMIA 4083(T)?=?CENA 183(T)?=?UMR1026(T)?=?CNPSo 141(T)) is designated the type strain of Rhizobium leucaenae sp. nov. PMID:21742822

Ribeiro, Renan Augusto; Rogel, Marco A; López-López, Aline; Ormeño-Orrillo, Ernesto; Barcellos, Fernando Gomes; Martínez, Julio; Thompson, Fabiano Lopes; Martínez-Romero, Esperanza; Hungria, Mariangela

2012-05-01

54

Phylogenetic relationships and host range of Rhizobium spp. that nodulate Phaseolus vulgaris L.  

Science.gov (United States)

We determined the nucleotide sequences of 16S rRNA gene segments from five Rhizobium strains that have been isolated from tropical legume species. All share the capacity to nodulate Phaseolus vulgaris L., the common bean. Phylogenetic analysis confirmed that these strains are of two different chromosomal lineages. We defined the host ranges of two strains of Rhizobium etli and three strains of R. tropici, comparing them with those of the two most divergently related new strains. Twenty-two of the 43 tested legume species were nodulated by three or more of these strains. All seven strains have broad host ranges that include woody species such as Albizia lebbeck, Gliricidia maculata, and Leucaena leucocephala. PMID:7618891

Hernandez-Lucas, I; Segovia, L; Martinez-Romero, E; Pueppke, S G

1995-07-01

55

Phylogenetic relationships and host range of Rhizobium spp. that nodulate Phaseolus vulgaris L.  

Science.gov (United States)

We determined the nucleotide sequences of 16S rRNA gene segments from five Rhizobium strains that have been isolated from tropical legume species. All share the capacity to nodulate Phaseolus vulgaris L., the common bean. Phylogenetic analysis confirmed that these strains are of two different chromosomal lineages. We defined the host ranges of two strains of Rhizobium etli and three strains of R. tropici, comparing them with those of the two most divergently related new strains. Twenty-two of the 43 tested legume species were nodulated by three or more of these strains. All seven strains have broad host ranges that include woody species such as Albizia lebbeck, Gliricidia maculata, and Leucaena leucocephala.

Hernandez-Lucas, I; Segovia, L; Martinez-Romero, E; Pueppke, S G

1995-01-01

56

Congo Red Absorption by Rhizobium leguminosarum  

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Congo red absorption is generally considered a contraindication of Rhizobium. However, R. leguminosarum takes up the dye on yeast extract-mannitol agar. The uptake of congo red varies among strains of R. leguminosarum, as shown elsewhere with strains of R. trifolii and R. meliloti. Congo red absorption does not distinguish rhizobia from other bacteria, but may be useful as a strain marker.

Kneen, Barbara E.; Larue, Thomas A.

1983-01-01

57

Transposon Tn5 specifies streptomycin resistance in Rhizobium spp.  

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Transposon Tn5 conferred streptomycin resistance on different strains of Rhizobium meliloti, Rhizobium leguminosarum, and Rhizobium trifolii but not on Escherichia coli. A gene (str) specifying this phenotype has been identified and localized on the physical and genetic map of Tn5. It is transcribed from the promoter of neo, the gene that encodes neomycin phosphotransferase. The str gene is downstream from neo in a single transcriptional unit, as revealed by molecular cloning of different seg...

1984-01-01

58

Recognition of Leguminous Hosts by a Promiscuous Rhizobium Strain  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The lima bean (Phaseolus lunatus L.) and the pole bean (Phaseolus vulgaris L.) are nodulated by rhizobia of two different cross-inoculation groups. Rhizobium sp. 127E15, a cowpea-type Rhizobium, can induce effective nodules on the lima bean and partially effective nodules on the pole bean. Rhizobium phaseoli 127K14 can induce effective nodules on the pole bean but does not reciprocally nodulate the lima bean. Root hairs of the lima bean when inoculated with Rhizobium sp. 127E15 showed tip cur...

Shantharam, S.; Wong, Peter P.

1982-01-01

59

Functional and evolutionary relatedness of genes for exopolysaccharide synthesis in Rhizobium meliloti and Rhizobium sp. strain NGR234.  

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Rhizobium meliloti SU47 and Rhizobium sp. strain NGR234 produce distinct exopolysaccharides that have some similarities in structure. R. meliloti has a narrow host range, whereas Rhizobium strain NGR234 has a very broad host range. In cross-species complementation and hybridization experiments, we found that several of the genes required for the production of the two polysaccharides were functionally interchangeable and similar in evolutionary origin. NGR234 exoC and exoY corresponded to R. m...

Zhan, H. J.; Gray, J. X.; Levery, S. B.; Rolfe, B. G.; Leigh, J. A.

1990-01-01

60

Characterization of the nodulation plasmid encoded chemoreceptor gene mcpG from Rhizobium leguminosarum  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background 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. Results A putative methyl accepting chemotaxis protein gene (mcpG of Rhizobium leguminosarum VF39SM was isolated and characterized. The gene was found to reside on the nodulation plasmid, pRleVF39d. The predicted mcpG ORF displayed motifs common to known methyl-accepting chemotaxis proteins, such as two transmembrane domains and high homology to the conserved methylation and signaling domains of well-characterized MCPs. Phenotypic analysis of mcpG mutants using swarm plates did not identify ligands for this putative receptor. Additionally, gene knockouts of mcpG did not affect a mutant strain's ability to compete for nodulation with the wild type. Notably, mcpG was found to be plasmid-encoded in all strains of R. leguminosarum and R. etli examined, though it was found on the nodulation plasmid only in a minority of strains. Conclusions Based on sequence homology R. leguminosarum mcpG gene codes for a methyl accepting chemotaxis protein. The gene is plasmid localized in numerous Rhizobium spp. Although localized to the sym plasmid of VF39SM mcpG does not appear to participate in early nodulation events. A ligand for McpG remains to be found. Apparent McpG orthologs appear in a diverse range of proteobacteria. Identification and characterization of mcpG adds to the family of mcp genes already identified in this organism.

Del Bel Kate L

2003-01-01

 
 
 
 
61

Conservation between coding and regulatory elements of Rhizobium meliloti and Rhizobium leguminosarum dct genes.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Complementation of Rhizobium leguminosarum dct mutants with a cosmid bank yielded Rhizobium meliloti homologs of the dctA, dctB, and dctD genes. The genes dctB and dctD are thought to form a two-component system which responds to the presence of C4-dicarboxylates to regulate expression of a transport protein encoded by dctA. DNA sequence analysis showed that dct coding and intergenic regions, including putative binding sites for the dctD protein and sigma 54-RNA polymerase, were highly conser...

Jiang, J.; Gu, B. H.; Albright, L. M.; Nixon, B. T.

1989-01-01

62

Effectiveness of Rhizobium Under Salinity Stress  

Directory of Open Access Journals (Sweden)

Full Text Available This research work was conducted to evaluate the efficacy of Rhizobium trifolii in enhancing the salt tolerance of Trifolium alexandrinum (Berseem or Egyptian clover, protein value of fodder and nitrogen fixation in the soil. Three salinity levels (8,12, 16 dS m-1 were developed in a loamy soil in pots. A similar set of inoculated pots with Rhizobium trifolii was also arranged. Berseem crop was grown in both of the sets. The data indicated that total green and dry matter yield as well as root dry weight of berseem decreased consecutively with increase in salinity level while Rhizobium inoculation created a positive effect and these parameters remained significantly higher than the similar levels without inoculation. Nodulation and nodule dry weight was promoted markedly by inoculation and depressed significantly with consistent increase in salinity. Nitrogen percentage of berseem shoot increased with inoculation and decreased significantly at 8 dS m 1 but further increase in salinity had a little effect. Percent nitrogen of soil and nitrogen fixation in soil was enhanced significantly by inoculation and decreased significantly with increase in salinity. Inoculation was helpful to keep the protein content higher. Soil ECe and pH were lowered.

Nazir Hussain

2002-01-01

63

Biodegradation of Phosphonomycin by Rhizobium huakuii PMY1  

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The biodegradation by Rhizobium huakuii PMY1 of up to 10 mM phosphonomycin as a carbon, energy, and phosphorus source with accompanying Pi release is described. This biodegradation represents a further mechanism of resistance to this antibiotic and a novel, phosphate-deregulated route for organophosphonate metabolism by Rhizobium spp.

Mcgrath, John W.; Hammerschmidt, Friedrich; Quinn, John P.

1998-01-01

64

Nodulation of Acacia Species by Fast- and Slow-Growing Tropical Strains of Rhizobium  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thirteen Acacia species were classified into three groups according to effective nodulation response patterns with fast- and slow-growing tropical strains of Rhizobium. The first group nodulated effectively with slow-growing, cowpea-type Rhizobium strains; the second, with fast-growing Rhizobium strains; and the third, with both fast- and slow-growing Rhizobium strains. The Rhizobium requirements of the Acacia species of the second group were similar to those of Leucaena leucocephala.

Dreyfus, B. L.; Dommergues, Y. R.

1981-01-01

65

Structural assessment of the role of the cell surface carbohydrates of Rhizobium in the Rhizobium/legume symbiosis. Progress report, June 1989--June 1991.  

Science.gov (United States)

Research continued on the study of cell surface carbohydrates of Rhizobium. Objectives include: To characterize, at a structural level, the differences between the lipopolysaccharides of a representative number of strains from different Rhizobium species ...

R. I. Hollingsworth

1991-01-01

66

Effect of Rhizobium Inoculation on Seedling Growth of Albizia niopides (Spruce Ex Bnth) Burkart  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Investigation was carried out on the effect of Rhizobium inoculation on the Seedling Growth and development of Albizia niopoides in a glass house at the International Institute of Tropical Agriculture (IITA) Ibadan Nigeria. This involved isolation of Rhizobium from this species microbiologically. There were four treatments in all namely 1 mL Rhizobium inoculation; 5 mL Rhizobium inoculation; 10 mL Rhizobium inoculation and control (without Rhizobium inoculation). They were ...

Okunomo, K.; Bosah, B. O.; Ofuoku, A. U.; Okunomo, J. N.

2007-01-01

67

Delayed maturation of nodules reduces symbiotic effectiveness of the Lotus japonicus–Rhizobium sp. NGR234 interaction  

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Lotus japonicus, a model legume, develops an efficient, nitrogen-fixing symbiosis with Mesorhizobium loti that promotes plant growth. Lotus japonicus also forms functional nodules with Rhizobium sp. NGR234 and R. etli. Yet, in a plant defence-like reaction, nodules induced by R. etli quickly degenerate, thus limiting plant growth. In contrast, nodules containing NGR234 are long-lasting. It was found that NGR234 initiates nodule formation in a similar way to M. loti MAFF303099, but that the no...

Schumpp, Olivier; Cre?vecoeur, Miche?le; Broughton, William J.; Deakin, William J.

2009-01-01

68

Rhizobium sullae sp. nov. (formerly 'Rhizobium hedysari'), the root-nodule microsymbiont of Hedysarum coronarium L.  

Science.gov (United States)

This work is the completion of a series of reports describing the nitrogen-fixing bacterial symbionts of sulla (Hedysarum coronarium L., Leguminosae) and providing the grounds for their proposal as a new taxon. The introduction summarizes a large amount of previous evidence gathered on the physiology, genetics and ecology of such organisms, which have in the past been referred to provisionally as 'Rhizobium hedysari'. Upon adding 16S RNA sequencing, amplified rDNA restriction analysis of the rrn operon, DNA-DNA hybridization homology and analysis of low-molecular-mass RNA species, it is concluded that the group of strains that specifically nodulate sulla consists of a coherent set of isolates that differ from previously described rhizobia to an extent that warrants the constitution of the species boundary. The name Rhizobium sullae sp. nov. is proposed, with isolate 1S123T (=USDA 4950T = DSM 14623T) as the type strain. PMID:12148639

Squartini, Andrea; Struffi, Paolo; Döring, Heidi; Selenska-Pobell, Sonja; Tola, Elisabetta; Giacomini, Alessio; Vendramin, Elena; Velázquez, Encarna; Mateos, Pedro F; Martínez-Molina, Eustoquio; Dazzo, Frank B; Casella, Sergio; Nuti, Marco P

2002-07-01

69

Rhizobium leguminosarum mutants incapable of normal extracellular polysaccharide production.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Mutants of Rhizobium leguminosarum which are deficient in normal polysaccharide production have been isolated and characterized. A correlation between diminished production of extracellular polysaccharide and reduced infection and nodulation efficiency has been observed.

Napoli, C.; Albersheim, P.

1980-01-01

70

Rhizobium laguerreae sp. nov. nodulates Vicia faba on several continents.  

Science.gov (United States)

Several fast-growing strains nodulating Vicia faba in Peru, Spain and Tunisia formed a cluster related to Rhizobium leguminosarum. The 16S rRNA gene sequences were identical to that of R. leguminosarum USDA 2370(T), whereas rpoB, recA and atpD gene sequences were phylogenetically distant, with sequence similarities of less than 96?%, 97?% and 94?%, respectively. DNA-DNA hybridization analysis showed a mean relatedness value of 43?% between strain FB206(T) and R. leguminosarum USDA 2370(T). Phenotypic characteristics of the novel strains also differed from those of the closest related species of the genus Rhizobium. Therefore, based on genotypic and phenotypic data obtained in this study, we propose to classify this group of strains nodulating Vicia faba as a novel species of the genus Rhizobium named Rhizobium laguerreae sp. nov. The type strain is FB206(T) (?=?LMG 27434(T)?=?CECT 8280(T)). PMID:24067731

Saïdi, Sabrine; Ramírez-Bahena, Martha-Helena; Santillana, Nery; Zúñiga, Doris; Álvarez-Martínez, Estela; Peix, Alvaro; Mhamdi, Ridha; Velázquez, Encarna

2014-01-01

71

Heme compounds as iron sources for nonpathogenic Rhizobium bacteria.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Many animal-pathogenic bacteria can use heme compounds as iron sources. Like these microorganisms, rhizobium strains interact with host organisms where heme compounds are available. Results presented in this paper indicate that the use of hemoglobin as an iron source is not restricted to animal-pathogenic microorganisms. We also demonstrate that heme, hemoglobin, and leghemoglobin can act as iron sources under iron-depleted conditions for Rhizobium meliloti 242. Analysis of iron acquisition m...

1997-01-01

72

Characterization of Two Inducible Phosphate Transport Systems in Rhizobium tropici  

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Rhizobium tropici forms nitrogen-fixing nodules on the roots of the common bean (Phaseolus vulgaris). Like other legume-Rhizobium symbioses, the bean-R. tropici association is sensitive to the availability of phosphate (Pi). To better understand phosphorus movement between the bacteroid and the host plant, Pi transport was characterized in R. tropici. We observed two Pi transport systems, a high-affinity system and a low-affinity system. To facilitate the study of these transport systems, a T...

Botero, Lina M.; Al-niemi, Thamir S.; Mcdermott, Timothy R.

2000-01-01

73

Phylogenetic diversity of Rhizobium strains nodulating diverse legume species growing in Ethiopia.  

Science.gov (United States)

The taxonomic diversity of thirty-seven Rhizobium strains, isolated from nodules of leguminous trees and herbs growing in Ethiopia, was studied using multilocus sequence analyses (MLSA) of six core and two symbiosis-related genes. Phylogenetic analysis based on the 16S rRNA gene grouped them into five clusters related to nine Rhizobium reference species (99-100% sequence similarity). In addition, two test strains occupied their own independent branches on the phylogenetic tree (AC86a2 along with R. tibeticum; 99.1% similarity and AC100b along with R. multihospitium; 99.5% similarity). One strain from Milletia ferruginea was closely related (>99%) to the genus Shinella, further corroborating earlier findings that nitrogen-fixing bacteria are distributed among phylogenetically unrelated taxa. Sequence analyses of five housekeeping genes also separated the strains into five well-supported clusters, three of which grouped with previously studied Ethiopian common bean rhizobia. Three of the five clusters could potentially be described into new species. Based on the nifH genes, most of the test strains from crop legumes were closely related to several strains of Ethiopian common bean rhizobia and other symbionts of bean plants (R. etli and R. gallicum sv. phaseoli). The grouping of the test strains based on the symbiosis-related genes was not in agreement with the housekeeping genes, signifying differences in their evolutionary history. Our earlier studies revealing a large diversity of Mesorhizobium and Ensifer microsymbionts isolated from Ethiopian legumes, together with the results from the present analysis of Rhizobium strains, suggest that this region might be a potential hotspot for rhizobial biodiversity. PMID:23643092

Degefu, Tulu; Wolde-meskel, Endalkachew; Frostegård, Åsa

2013-06-01

74

Basis for the Competitiveness of Rhizobium Japonicum in Nodulation of Soybean. Progress Report, 1984.  

Science.gov (United States)

Those characteristics of Rhizobium cells that are most crucial in determining their competitive success when inoculated onto seed in the field are sought. Initial studies of Rhizobium attachment to root surfaces revealed that only a small subpopulation of...

W. D. Bauer W. R. Evans

1984-01-01

75

Absorción de cobre y características de Leucaena leucocephala asociada con Glomus spp. y Rhizobium en suelo contaminado del Río Lerma, México  

Directory of Open Access Journals (Sweden)

Full Text Available El objetivo de esta investigación fue evaluar (a la capacidad de absorción de Cu por Leucaena leucocephala y (b el efecto en sus características agronómicas al inocularse con hongos endomicorrízicos arbusculares y Rhizobium como alternativa para la fitorremediación de suelos agrícolas contaminados. El trabajo se realizó en condiciones de invernadero en suelo contaminado por Cu procedente de la parte alta de la cuenca del río Lerma, estado de México. Las plantas de Leucaena crecieron en bolsas de polietileno negro con 3 kg del suelo contaminado esterilizado o no esterilizado. Se aplicaron 0, 20 y 200 mg de Cu kg-1 de suelo contaminado tratado con Glomus sp. Zac-19, Glomus intraradices o sin Glomus, e inoculado con Rhizobium o sin Rhizobium. Se evaluaron la acumulación de Cu en las plantas, sus características agronómicas y el contenido final de Cu en el suelo. La acumulación de Cu en las plantas fue mayor en tallos que en hojas y se asoció a la disminución de su concentración en el suelo a través del tiempo. No hubo efecto de la esterilización del suelo sobre la acumulación de Cu, ni sobre las características agronómicas de las plantas, excepto sobre el número de nódulos de Rhizobium. Se observó significativamente (P < 0.05 mayor acumulación de Cu al incrementarse su concentración en el suelo, destacando un efecto positivo de 20 mg de Cu kg-1 de suelo al mejorar las características agronómicas. Las plantas con mejores características agronómicas disminuyeron su tendencia a la absorción de Cu en presencia simultánea de Glomus spp. y Rhizobium. Esto demuestra un efecto interactivo positivo de la doble inoculación endomicorriza más Rhizobium en la absorción de Cu por las plantas de Leucaena y aumenta su papel en el diseño de estrategias de reforestación y fitorremediación de suelos agrícolas contaminados por cobre.

Abdul Khalil Gardezi

2006-01-01

76

The beneficial effect of dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover  

Directory of Open Access Journals (Sweden)

Full Text Available Investigation on the effect of phosphorus on vesicular-arbuscular mycorrhizal infection, and dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover under field microplots and pot experiments was conducted on fluvo-aquic soils of semi-arid region in north China. The results showed that 60 kg P205 ha in form of superphosphate was the most favorable phosphorus level for vesicular-arbuscular mycorrhizal infection ; mycorrhizal infection, nodulation, dry weight of shoots and roots, total uptake of nitrogen, phosphorus and other elements, the final yields and recovery of phosphorus of white clover were significantly increased by vesicular-arbuscular mycorrhizal inoculation and dual inoculation with vesicular-arbuscular mycorrhizal fungi and rhizobium. The highest response of inoculation was obtained by adding fertilizer phosphorus at the level of 60 kg P205 ha in form of superphosphate.

Lin, XG.

1993-01-01

77

Rhizobium meliloti genes required for nodule development are related to chromosomal virulence genes in Agrobacterium tumefaciens  

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Symbiotically essential genes have been identified in Rhizobium meliloti that are structurally and functionally related to chromosomal virulence (chv) genes of Agrobacterium tumefaciens. Homologous sequences also exist in the genomes of other fast-growing rhizobia including Rhizobium trifolii, Rhizobium leguminosarum, and Rhizobium phaseoli. In Agrobacterium, the chvA and chvB loci are known to be essential for oncogenic transformation of dicotyledonous plants and for attachment to plant cell...

Dylan, T.; Ielpi, L.; Stanfield, S.; Kashyap, L.; Douglas, C.; Yanofsky, M.; Nester, E.; Helinski, D. R.; Ditta, G.

1986-01-01

78

Heterologous exopolysaccharide production in Rhizobium sp. strain NGR234 and consequences for nodule development.  

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Rhizobium sp. strain NGR234 produces large amounts of acidic exopolysaccharide. Mutants that fail to synthesize this exopolysaccharide are also unable to nodulate the host plant Leucaena leucocephala. A hybrid strain of Rhizobium sp. strain NGR234 containing exo genes from Rhizobium meliloti was constructed. The background genetics and nod genes of Rhizobium sp. strain NGR234 are retained, but the cluster of genes involved in exopolysaccharide biosynthesis was deleted. These exo genes were re...

Gray, J. X.; Zhan, H. J.; Levery, S. B.; Battisti, L.; Rolfe, B. G.; Leigh, J. A.

1991-01-01

79

Identification of Rhizobium plasmid sequences involved in recognition of Psophocarpus, Vigna, and other legumes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Symbiotic DNA sequences involved in nodulation by Rhizobium must include genes responsible for recognizing homologous hosts. We sought these genes by mobilizing the symbiotic plasmid of a broad host-range Rhizobium MPIK3030 (= NGR234) that can nodulate Glycine max, Psophocarpus tetragonolobus, Vigna unguiculata, etc., into two Nod- Rhizobium mutants as well as into Agrobacterium tumefaciens. Subsequently, cosmid clones of pMPIK3030a were mobilized into Nod+ Rhizobium that cannot nodulate the ...

1986-01-01

80

78 FR 33437 - United States v. Apple, Inc., et al.; Public Comments and Response on Proposed Final Judgment  

Science.gov (United States)

...JUSTICE Antitrust Division United States v. Apple, Inc., et al.; Public Comments and...b/a Macmillan in United States v. Apple, Inc., et al., Civil Action No. 12-CV-2826...www.justice.gov/atr/cases/apple/index-2.html, and at the...

2013-06-04

 
 
 
 
81

Physiological role of calcium in legume-rhizobium symbiosis  

Directory of Open Access Journals (Sweden)

Full Text Available Literature data on the physiological role of calcium (Ca2+ in legume-rhizobium symbiosis development on initial stages - the infection and symbiotic structures formation, are generalized. The questions about the Ca2+ function in plants, special feature the formation of legume-rhizobium symbiosis and role of calcium in the interaction of two organisms are considered. Data on the interaction of ROS and Ca2+ in the development of the legume-rhizobium symbiosis and the relationship of NADPH-oxidase activity with the calcium signaling system are analyzed. The special attention is given to the role of Ca22+-spiking and calcium and calmodulin-like kinase in the initiation of plant symbiotic ways operation leads to infection and the formation of symbiotic structures.

Vasil’eva G.G.

2011-12-01

82

Étude des transactions en matière de santé entre les individus, leurs familles et leurs milieux de vie: rapport final.  

Canada Institute for Scientific and Technical Information (Canada)

Résumé: Les travaux réalisés dans le cadre de cette subvention de recherche constituent une tentative pour élucider les liens entre certaines issues de santé, les environnements familiaux et communautaires dans lesquels les gens vivent et leur statut socio-économique. Pour ce faire, nous avons recueilli de nouvelles données afin de compléter des données d'enquêtes existantes concernant le tabagisme et la pratique d'activités physiques de loisir. Les données existantes provenaient d'une cohorte de familles assemblée lors d'une étude précédente. Les nouvelles données concernent certaines caractéristiques de leurs milieux de vie et dessinent un portrait socio-démographique des quartiers de résidence à l'aide des données du recensement de 1996. Les travaux empiriques réalisés pour ce projet ont consisté principalement à délimiter les environnements locaux des familles de la cohorte, à identifier, à l'intérieur des territoires ainsi déterminés, un ensemble de ressources qui facilitent ou restreignent les comportements sous étude et à élaborer un appareillage pour en faire l'inventaire et ainsi caractériser les environnements locaux selon qu'ils favorisent ou non le tabagisme et la pratique d'activités physiques de loisir. Les familles de la cohorte provenaient de trois sites: un site urbain (centre ville de Montréal) pour lequel 13 territoires locaux ont été définis, un site de banlieue (Laval) duquel nous avons tiré 5 territoires locaux et un site rural (Bas-du-Fleuve) qui a produit 14 territoires locaux. C'est en fonction de trois grandes composantes que nous avons caractérisé les trente-deux territoires, soit : 1) les agents sociaux de santé; 2) les ressources de santé; 3) le profil socio- démographique. Les agents sociaux qui nous intéressent sont toutes les organisations privées, publiques ou communautaires qui, dans un territoire donné, vendent ou mettent à la disposition d'individus des biens ou des services qui facilitent ou découragent le tabagisme ou la pratique d'activités physiques. A l'aide des données des municipalités nous avons établi une liste préliminaire d'environ 3500 agents que nous avons contactés par téléphone. Nous avons ainsi confirmé qu'un total de 2028 agents fournissent des ressources relatives au tabagisme ou à la pratique d'activités physiques dans les 32 territoires sous étude. Nous avons ensuite effectué un recensement des ressources relatives au tabagisme ou à la pratique d'activités physiques de loisir dans des échantillons d'organismes communautaires, publics et privés, dans chacun des 32 territoires sous étude. Nous avons caractérisé ces ressources selon qu'elles facilitent (ressources positives) ou découragent (ressources négatives) le comportement auquel elles sont reliées, et selon le mode sous lequel elles se présentent. Enfin, à l'aide des codes postaux correspondant à chacun des territoires, nous avons obtenu de Statistique Canada un fichier de tableaux semi personnalisés qui contiennent les principales caractéristiques socio-démographiques des territoires. En conclusion, nos travaux mettent en évidence l'importance de considérer un ensemble de facteurs à la fois et supportent le plaidoyer de McKinlay et Marceau (1999) pour qui la quête du "facteur miracle" qui expliquerait, à lui seul, la santé et la maladie, est une chimère. La santé est un phénomène complexe qui résulte d'interactions complexes. C'est à l'ensemble des facteurs impliqués dans la production sociale de la santé et de la maladie que les interventions de santé publique doivent s'adresser. Certains types de milieux de vie seraient plus propices au maintien et à la promotion de la santé que d'autres et ce, en lien avec les ressources matérielles dont disposent les gens. Le développement des milieux de vie apparaît donc comme un objectif légitime pour les organisations de santé publique. Cette étude illustre aussi que les populations locales interprètent la présence etla signification de ces ressources

2000-01-01

83

Removal of chromium using Rhizobium leguminosarum.  

Science.gov (United States)

The chromium (Cr(III) and Cr(VI)) removal capability of Rhizobium leguminosarum was checked by estimating the amount of chromium in the medium before and after inoculation. To determine the efficiency of R. leguminosarum in removal of chromium, the influence of physical and chemical parameters such as temperature, pH and different concentrations (0.1-1.0 mM) of trivalent (Cr(III)) and hexavalent (Cr(VI)) chromium were studied. The chromium removal in aqueous solution by different size of active and inactivated biomass and immobilized cells of R. leguminosarum in a packed-bed column was also carried out. Results showed that in a medium containing up to 0.5 mM concentration of both Cr(III) and Cr(VI), R. leguminosarum showed optimal growth. The maximum chromium removal was at pH 7.0 and 35°C. Active biomass removed 84.4 ± 3.6% of Cr(III) and 77.3 ± 4.3% of Cr(VI) in 24 h of incubation time. However, inactivated biomass removed maximum chromium after 36 h of incubation. Immobilized bacterial cells in a packed-bed column removed 86.4 ± 1.7% of Cr(III) and 83.8 ± 2.2% of Cr(VI) in 16 and 20 h of incubation time, respectively. PMID:22806858

Raaman, N; Mahendran, B; Jaganathan, C; Sukumar, S; Chandrasekaran, V

2012-02-01

84

Rhizobium japonicum nitrogenase Fe protein gene (nifH).  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A 12.1-kilobase PstI fragment from Rhizobium japonicum, which contains homology to both the Klebsiella pneumoniae and the Rhizobium meliloti nifH genes, was cloned into vector pHE3 . The nifH -homologous region was localized on the restriction enzyme cleavage map by Southern blot hybridization experiments. DNA fragments overlapping the R. japonicum nifH gene were subcloned into plasmid vectors to allow the expression of this region in Escherichia coli minicells. The nifH gene product (the pol...

1984-01-01

85

Structural and regulatory analysis of quorum sensing in Rhizobium leguminosarum  

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In the present work, we have studied the role of quorum-sensing regulatory systems in Rhizobium-legume symbiosis. Competition assays suggest that inactivation of quorum sensing systems significantly affects the competitiveness of Rhizobium leguminosarum bv. viciae UPM791 (Rl UPM791) when compared to other strains. Structural analysis through HPLC / mass spectrometry revealed that the signals produced by Rl UPM791 correspond to: C6-HSL, C7-HSL, C8-HSL and 3OH-C14-HSL; also, small amount...

Sanchez Can?izares, Carmen; Morata Barrado, Antonio; Cantero, L.; Jorrin, Beatriz; Ruiz Argu?eso, Tomas-andres; Imperial Ro?denas, Juan; Palacios Alberti, Jose Manuel

2010-01-01

86

Inoculação com Rhizobium e aplicação de nitrogênio em amendoim Comparison among Rhizobium strains inoculations and nitrogen applications on peanut, in field conditions  

Directory of Open Access Journals (Sweden)

Full Text Available Existe, nas nossas condições, uma população autóctone de Rhizobium capaz de nodular o amendoim (Arachis hypogaea L., mas pouco se sabe da contribuição do nitrogênio fixado para esta planta. Foram conduzidos dois ensaios no campo, em solo de baixa fertilidade, um no período "da seca" e outro no "das águas", comparando o crescimento e a produção de plantas de amendoim inoculado com Rhizobium selecionado, com o de plantas noduladas pela população autóctone, adubadas ou não com nitrogênio. A nodulação das plantas inoculadas foi semelhante à observada nos tratamentos não inoculados, com ou sem nitrogênio. Na fase final do ciclo das plantas, houve maior acúmulo e maior taxa de absorção diária de nitrogênio nos tratamentos inoculados ou com adubação nitrogenada, do que no controle sem inoculação e sem nitrogênio. No ensaio da seca, não houve aumento de produção devido à adubação nitrogenada, ou à inoculação. No ensaio das águas, houve resposta à aplicação de nitrogênio no plantio. Os resultados de produção não foram coerentes com os da marcha de absorção de N. A produção de ensaio das águas foi equivalente a 3.400 kg/ha para o tratamento sem nitrogênio e sem inoculação.Two field experiments were carried out with peanut in the same area on a limed and fertilized "cerrado soil" (originally acidic and low fertility. The first experiment was carried out in the autumn/winter (dry season, and the second one in the subsequent spring/summer (wet season, in Campinas, State of São Paulo, Brazil. Plant development and production of inoculated (three Rhizobium strains and nitrogen fertilized treatments (at planting 25 and 45 days after planting were compared with non-inoculated and non-N-fertilized control. Nodulation of inoculated plants was similar to those of non-inoculated, with or without nitrogen. Greater accumulations, and rates for average daily uptake of nitrogen were observed for inoculated as well as for nitrogen fertilized plants, as compared to the control. In the autumn/winter experiment there was no increase in pod production neither due to nitrogen or to inoculation. In the spring/summer experiment however, the pod production was higher with nitrogen (30kg/N/ha at planting, although higher nitrogen accumulations in plant shoots (sampled 84 days after planting were observed treatments with two of the three inoculated strains.

Antonio Roberto Giardini

1985-01-01

87

Bacteremia caused by Rhizobium radiobacter in a preterm neonate.  

Science.gov (United States)

The authors report a case of bacteremia due to Rhizobium radiobacter in a preterm neonate. Although the baby recovered from the septic episode following therapy with appropriate antibiotics he succumbed to complications, mainly associated with prematurity. This case highlights a rare manifestation of R.radiobacter infection in a neonate in whom the source of the organism remained undiscovered. PMID:23539251

Khan, Seema; Al-Sweih, Noura; Othman, Abdul Hafez; Dhar, Rita

2014-02-01

88

Infection and nodulation of clover by nonmotile Rhizobium trifolii.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nonmotile mutants of Rhizobium trifolii were isolated to determine whether bacterial motility is required for the infection and nodulation of clover. The nonmotile mutants were screened for their ability to infect and nodulate clover seedlings in Fahraeus glass slide assemblies, plastic growth pouches, and vermiculite-sand-filled clay pots. In each system, the nonmotile mutants were able to infect and nodulate clover.

Napoli, C.; Albersheim, P.

1980-01-01

89

Analysis of Rhizobium meliloti Sym Mutants Obtained by Heat Treatment †  

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Deletions in the pSym megaplasmid of Rhizobium meliloti were produced at a high frequency, and their lengths varied according to incubation temperature. Morphological differentiation into large and small colonies occurred after heat treatment. Small colonies elicited pseudonodules on alfalfa roots.

Toro, Nicolas; Olivares, Jose?

1986-01-01

90

Rhizobium rhizoryzae sp. nov., isolated from rice roots.  

Science.gov (United States)

Two strains (J3-AN59(T) and J3-N84) of Gram-stain-negative, aerobic and rod-shaped bacteria were isolated from the roots of fresh rice plants. The 16S rRNA gene sequence similarity results showed that the similarity between strains J3-AN59(T) and J3-N84 was 100?%. Both strains were phylogenetically related to members of the genus Rhizobium, and they were most closely related to Rhizobium tarimense ACCC 06128(T) (97.43?%). Similarities in the sequences of housekeeping genes between strains J3-AN59(T) and J3-N84 and those of recognized species of the genus Rhizobium were less than 90?%. The polar lipid profiles of both strains were predominantly composed of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unknown aminophospholipid. The major cellular fatty acids were summed feature 8 (C18?:?1?7c and/or C18?:?1?6c) and C16?:?0. The DNA G+C contents of J3-AN59(T) and J3-N84 were 55.7 and 57.1 mol%, respectively. The DNA-DNA relatedness value between J3-AN59(T) and J3-N84 was 89?%, and strain J3-AN59(T) showed 9?% DNA-DNA relatedness to R. tarimense ACCC 06128(T), the most closely related strain. Based on this evidence, we found that J3-AN59(T) and J3-N84 represent a novel species in the genus Rhizobium and we propose the name Rhizobium rhizoryzae sp. nov. The type strain is J3-AN59(T) (?=?ACCC 05916(T)?=?KCTC 23652(T)). PMID:24449787

Zhang, Xiao-Xia; Tang, Xue; Sheirdil, Rizwan Ali; Sun, Lei; Ma, Xiao-Tong

2014-04-01

91

The Effect of Rhizobium spp. Inoculation on Seed Quality of Bean in Turkey  

Directory of Open Access Journals (Sweden)

Full Text Available Rhizobium spp. (local isolate was used to inoculate three bean (Phaseolus vulgaris L. varieties; Akman 98, Goynuk 98 and Sehirali 90, in a factorial field experiment. The objective of the experiment was to study effect of inoculation on seed yield, protein range, seed weight, non-soaker capacity and hydration index. Rhizobium spp. inoculation and nitrogen fertilizer significantly increased characters tested. This study revealed that inoculation with Rhizobium spp. improved seed quality.

Cigdem KuCuk

2008-01-01

92

Interaction of Azospirillum and Rhizobium Strains Leading to Inhibition of Nodulation  

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Rhizobium-Azospirillum interactions during establishment of Rhizobium-clover symbiosis were studied. When mixed cultures of Azospirillum and Rhizobium trifolii strains were simultaneously inoculated onto clover plants, no nodulation by R. trifolii was observed. R. trifolii ANU1030, which nodulated clover plants without attacking root hairs, i.e., does not cause root hair curling (Hac?), did not show inhibition of nodulation when inoculated together with Azospirillum strains. Isolation of ba...

Plazinski, Jacek; Rolfe, Barry G.

1985-01-01

93

The effect of exogenous rhizobial lipopolysaccharide on symbiosis of Rhizobium leguminosarum bv. trifolii with red clover  

Directory of Open Access Journals (Sweden)

Full Text Available The effectivity of symbiosis of Rhizobium leguminosarum bv. trifolii with red clover in the presence of exogenous lipopolysaccharide (LPS preparation was measured as a yield of green mass of infected plants. The addition of complete LPS that had been obtained from homological Rhizobium strains influenced significantly the growth of plants. In the presence of defective LPS of Rhizobium mutant the effectivity of symbiosis did not change.

Maria G?owacka

1996-12-01

94

Use of Two-Dimensional Polyacrylamide Electrophoresis to Demonstrate that Putative Rhizobium Cross-Inoculation Mutants Actually Are Contaminants  

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Two-dimensional polyacrylamide electrophoresis was used to determine that mutants of Rhizobium trifolii DT6, claimed to be capable of effectively nodulating soybeans, were actually Rhizobium japonicum 110 contaminants isolated from the parent DT6 culture.

Leps, Walter T.; Roberts, G. P.; Brill, Winston J.

1980-01-01

95

Rhizobium as a Biological Agent for Preventing Heavy Metal Stress  

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Full Text Available In the present study, Rhizobium was used as soil fertilizer to prevent the stress of lead on growing Pisum sativum. Three concentrations of lead were used (50, 100 and 200 ppm. for the irrigation of growing plants (two times. After sowing, M2 seeds were collected, then cytological and biochemical studies were carried out. The cytological analysis revealed that soil enriched with Rhizobium increased the rate of mitotic division. A significant increase in mitotic index was detected. The kind of chromosomal abnormalities observed were; disturbances, stickiness, diagonals, chromosome breakage and c-metaphases. Also, a significant reduction in the percentage of abnormalities was observed. Biochemical studies included the analysis of M2 seed proteins using SDS-PAGE, isozyme analysis for both esterase and peroxidase and element analysis of Pb and N.

S.M. Abbas

2004-01-01

96

Factors Affecting the Efficiency of Symbiotic Nitrogen Fixation by Rhizobium  

Directory of Open Access Journals (Sweden)

Full Text Available Recent reports pointed to a decline in agricultural dependence on symbiotic nitrogen fixation, and in the use of rhizobial inoculants. The aim of the present review was to study the environmental factors that affect the efficiency of symbiotic nitrogen fixation by Rhizobium in soil. These factors included pH, salinity, moisture, temperature, microorganisms, organic matter and soil texture. The overall conclusion is that symbiotic nitrogen fixation by Rhizobium is a critical biological process. Environmental stresses are generally the limiting factors of the symbiotic nitrogen fixation. With the selection of the appropriate legume and rhizobial inoculant, nitrogen fixation can be increased and concomitantly food production can be improved even under environmentally stressed conditions.

Abdullah M. K. Al-Falih

2002-01-01

97

Efficient transformation of Mesorhizobium huakuii subsp. rengei and Rhizobium species.  

Science.gov (United States)

The transformation of Mesorhizobium huakuii subsp. rengei B3 with either pBBR122 or pKT230 was carried out. We determined the optimal conditions required for transformation by electroporation and obtained up to 10(5) CFU/microg pBBR122. Plasmids prepared from strain B3 yielded higher transformation efficiency than those from various dam or dcm mutant strains of Escherichia coli. This result suggests that a high transformation efficiency is not related to the methylation of plasmid DNA in E. coli. Using the optimal conditions for electroporation, we performed transformation of several species of Rhizobium, Mesorhizobium and Sinorhizobium. All tested strains of these species were transformed with pBBR122. Strains of M. huakuii and R. phaseoli AHU1133 were transformed at high efficiency, whereas transformation efficiencies of Rhizobium sp. NGR234 and S. meliloti strains were less than 2 x 10(3) CFU/microg plasmid DNA. PMID:16232796

Hayashi, M; Maeda, Y; Hashimoto, Y; Murooka, Y

2000-01-01

98

Dynamics of Genome Architecture in Rhizobium sp. Strain NGR234†  

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Bacterial genomes are usually partitioned in several replicons, which are dynamic structures prone to mutation and genomic rearrangements, thus contributing to genome evolution. Nevertheless, much remains to be learned about the origins and dynamics of the formation of bacterial alternative genomic states and their possible biological consequences. To address these issues, we have studied the dynamics of the genome architecture in Rhizobium sp. strain NGR234 and analyzed its biological signif...

Mavingui, Patrick; Flores, Margarita; Guo, Xianwu; Da?vila, Guillermo; Perret, Xavier; Broughton, William J.; Palacios, Rafael

2002-01-01

99

Nitrogenase reductase: A functional multigene family in Rhizobium phaseoli  

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The complete coding sequence of the nitrogenase reductase gene (nifH) is present in three different regions of a Rhizobium phaseoli symbiotic plasmid. Homology between two of the regions containing nifH coding sequences extends over 5 kilobases. These in turn share 1.3 kilobases of homology with the third region. The nucleotide sequences of the three nitrogenase reductase genes were found to be identical. Site-directed insertion mutagenesis indicated that none of the three genes is indispensa...

1985-01-01

100

Rhizobium phaseoli symbiotic mutants with transposon Tn5 insertions.  

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Rhizobium phaseoli CFN42 DNA was mutated by random insertion of Tn5 from suicide plasmid pJB4JI to obtain independently arising strains that were defective in symbiosis with Phaseolus vulgaris but grew normally outside the plant. When these mutants were incubated with the plant, one did not initiate visible nodule tissue (Nod-), seven led to slow nodule development (Ndv), and two led to superficially normal early nodule development but lacked symbiotic nitrogenase activity (Sna-). The Nod- mu...

1984-01-01

 
 
 
 
101

Fine Structure of Succinate-Swollen Rhizobium trifolii 0403  

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Transmission electron micrographs of glutaraldehyde- OsO4-fixed Rhizobium trifolii 0403 before and after cells were treated with 16.6 mM succinate showed that treated cells increased in mass by increasing cytoplasmic volume. The morphology of succinate-treated cells was identical to that of bacteroids, and the appearances of the envelope and periplasmic space were similar. The primary difference was in inclusion number and type.

Urban, James E.; Bechtel, Donald B.

1984-01-01

102

Aerobic purification of hydrogenase from Rhizobium japonicum by affinity chromatography.  

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We purified active hydrogenase from free-living Rhizobium japonicum by affinity chromatography. The uptake hydrogenase of R. japonicum has been treated previously as an oxygen-sensitive protein. In this purification, however, reducing agents were not added nor was there any attempt to exclude oxygen. In fact, the addition of sodium dithionite to aerobically purified protein resulted in the rapid loss of activity. Purified hydrogenase was more stable when stored under O2 than when stored under...

Stults, L. W.; Moshiri, F.; Maier, R. J.

1986-01-01

103

Transport and catabolism of D-mannose in Rhizobium meliloti.  

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Rhizobium meliloti L5-30 grows on D-mannose as the sole carbon source. The catabolic pathway of D-mannose was characterized. The following activities were present: mannose transport system, mannokinase, and mannosephosphate isomerase. Several mannose-negative mutants were selected; they were classified into three functional groups: group I, mannokinase and mannosephosphate isomerase defective: group II, mannokinase defective; and group III, mannosephosphate isomerase defective. Mannose uptake...

Arias, A.; Gardiol, A.; Marti?nez-drets, G.

1982-01-01

104

Estirpes de Rhizobium tropici na inoculação do feijoeiro  

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Full Text Available Avaliando o comportamento do feijoeiro inoculado com cinco estirpes de Rhizobium tropici e a adubação mineral com nitrogênio, sobre alguns fatores relacionados à sua produtividade, utilizou-se um delineamento experimental de blocos ao acaso, com oito tratamentos constituídos pela inoculação do feijoeiro cultivar IAC Carioca com cinco estirpes de Rhizobium tropici (CIAT 899 - estirpe referência; F35; F54; F81 e CM255, dois controles sem inoculação sendo um adubado com N na semeadura e em cobertura e outro sem adubação e um cultivar não nodulante (NORH 54 adubado; com seis repetições. Avaliaram-se: número de nódulos por planta; massa de material seco da parte aérea; teor de N nas folhas; número de vagens por planta; número de grãos por planta; número de grãos por vagem; peso de 100 grãos e produtividade de grãos. A inoculação de estirpes eficientes de Rhizobium em cultivar nodulante de feijoeiro, ou o cultivo deste em solos com população nativa eficiente, pode possibilitar a não utilização de nitrogênio em cobertura na cultura do feijoeiro, sem afetar a produtividade.

Ferreira Alessandro Nunes

2000-01-01

105

Surface carbohydrates of Rhizobium. I. Beta-1, 2-glucans.  

Science.gov (United States)

Because of increased interest in surface carbohydrates of Rhizobium in relation to host specificity, phenol-water extractions were carried out of whole cells of Rhizobium strains of the species R. leguminosarum, R. phaseoli, R. trifolii and R. meliloti. Fractionation of the crude extracts with cetavlon afforded polysaccharide mixtures, which were essentially free of RNA and acidic exopolysaccharide (EPS). They could be separated into a high molecular weight heteropolysaccharide fraction of lipopolysaccharide (LPS) nature and a low molecular weight glucan fraction. Glucan turned out to be the principal polysaccharide component of the cells (up to 10% of the dry cell weight), when cultivated in carbohydrate-rich media, and to be present as firmly attached capsular material. Glucan (mol wt 3000) structure was elucidated by methylation and periodate oxidation techniques. Methylation yielded 3, 4, 6-tri-O-methyl-D-glucose, characterized by GLC-MS, as the only product of hydrolysis of the fully methylated glucan. The glucan consumed 1 mole of periodate per mole anhydroglucose unit and gave sophorose on partial hydrolysis. From these data a linear beta-1,2-linked glucan structure was deduced. The occurrence of beta-1,2-glucan and the implications for the specific binding properties of Rhizobium cells are discussed. PMID:582886

Zevenhuizen, L P; Scholten-Koerselman, H J

1979-01-01

106

Effects of culture age on symbiotic infectivity of Rhizobium japonicum  

Energy Technology Data Exchange (ETDEWEB)

The infectivity of the soybean symbiont Rhizobium japonicum changed two- to fivefold with culture age for strains 110 ARS, 138 Str Spc, and 123 Spc, whereas culture age had relatively little effect on the infectivity of strains 83 Str and 61A76 Str. Infectivity was measured by determining the number of nodules which developed on soybean primary roots in the zone which contained developing and preemergent root hairs at the time of inoculation. Root cells in this region of the host root are susceptible to Rhizobium infection, but this susceptibility is lost during acropetal development and maturation of the root cells within a period of 4 to 6 h. Profiles of nodulation frequency at different locations on the root were not affected by the age of the R. japonicum cultures, indicating that culture age affected the efficiency of Rhizobium infection rather than how soon infections were initiated after inoculation. Inoculum dose-response experiments also indicated that culture age affected the efficiency of infection. Two strains, 61A76 Str and 83 Str, were relatively inefficient at all culture ages, particularly at low inoculum doses. Changes in infectivity with culture age were reasonably well correlated with changes in the proportion of cells in a culture capable of binding soybean lectin. Suspensions of R. japonicum in water were found to retain their viability and infectivity. 15 references, 6 figures, 2 tables.

Bhuvaneswari, T.V.; Mills, K.K.; Crist, D.K.; Evans, W.R.; Bauer, W.D.

1983-01-01

107

Novel and complex chromosomal arrangement of Rhizobium loti nodulation genes.  

Science.gov (United States)

A mutational and structural analysis of Rhizobium loti nodulation genes in strains NZP2037 and NZP2213 was carried out. Unlike the case with other Rhizobium strains examined to date, nodB was found on an operon separate from nodACIJ. Sequence analysis of the nodACIJ and nodB operon regions confirm that R. loti common nod genes have a gene organization different from that of other Rhizobium spp. At least 4 copies of nodD-like sequences were identified in R. loti. The complete nucleotide sequence of one of these, nodD3, was determined. A new host-specific nod gene, nolL, was identified adjacent to nodD3. NolL shares homology with NodX and other O-acetyl transferases. Mutational analysis of the nod regions of strains NZP2037 and NZP2213 showed that nodD3, nodI, nodJ, and nolL were all essential for R. loti strains to effectively nodulate the extended host Lotus pedunculatus, but were not necessary for effective nodulation of the less restrictive host, Lotus corniculatus. Both nodD3 and nolL were essential for R. loti strains to nodulate Leucaena leucocephala. PMID:8850088

Scott, D B; Young, C A; Collins-Emerson, J M; Terzaghi, E A; Rockman, E S; Lewis, P E; Pankhurst, C E

1996-04-01

108

The impact of the EU ETS on electricity prices. Final report to DG Environment of the European Commission  

International Nuclear Information System (INIS)

On February 2, 2009, a revised edition of the report has been released, including some adjustments and editorial corrections particularly in Section 2.2 and Appendix A. The present study analyses the impact of the EU Emissions Trading Scheme (ETS) on electricity prices, in particular on wholesale power markets across the EU. To study this impact, a variety of methodological approaches is used, including theoretical, empirical, model, literature and policy analyses. The study shows that a significant part of the costs of freely allocated CO2 emission allowances is passed through to power prices, resulting in higher electricity prices for consumers and additional ('windfall') profits for power producers. In addition, it discusses some policy implications of the pass-through of these costs. It concludes that the pass-through of CO2 costs to electricity prices is a rational, carbon-efficient policy, while the issue of windfall profits can be addressed by either taxing these profits or auctioning - rather than free allocations - of the emission allowances

2008-01-01

109

In Rhizobium japonicum the nitrogenase genes nifH and nifDK are separated.  

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In contrast to Klebsiella pneumoniae or fast-growing Rhizobium species, such as R. meliloti, where the nitrogenase structural genes are clustered in one operon (nifHDK), in slow-growing Rhizobium japonicum 110, nifH and nifDK are on separate operons.

Kaluza, K.; Fuhrmann, M.; Hahn, M.; Regensburger, B.; Hennecke, H.

1983-01-01

110

Preliminary data on some correlations of Rhizobium and radio-stimulation seed treatments  

International Nuclear Information System (INIS)

The seeds of peas, beans, soy-beans and lucerne were treated with 60Co-irradiation (4-10 Gray). The size of the roots and the quantity of seed-crop were measured. Irradiation by itself had no significant effect. Treatment with Rhizobium bacteria and with Rhizobium plus irradiation had considerable positive effects. (L.E.)

1979-12-01

111

Expression of symbiotic genes of Rhizobium japonicum USDA 191 in other rhizobia.  

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A 200-megadalton plasmid was mobilized from Rhizobium japonicum USDA 191 to other Rhizobium strains either that cannot nodulate soybeans or that form Fix- nodules on certain cultivars. The symbiotic properties of the transconjugants indicate that both soybean specificity for nodulation and cultivar specificity for nitrogen fixation are plasmid encoded.

Appelbaum, E. R.; Mcloughlin, T. J.; O Connell, M.; Chartrain, N.

1985-01-01

112

Rhizobium pisi sv. trifolii K3.22 harboring nod genes of the Rhizobium leguminosarum sv. trifolii cluster.  

Science.gov (United States)

The taxonomic status of the Rhizobium sp. K3.22 clover nodule isolate was studied by multilocus sequence analysis (MLSA) of 16S rRNA and six housekeeping chromosomal genes, as well as by a subsequent phylogenic analysis. The results revealed full congruence with the Rhizobium pisi DSM 30132(T) core genes, thus supporting the same taxonomic position for both strains. However, the K3.22 plasmid symbiosis nod genes demonstrated high sequence similarity to Rhizobium leguminosarum sv. trifolii, whereas the R. pisi DSM 30132(T)nod genes were most similar to R. leguminosarum sv. viciae. The strains differed in the host range nodulation specificity, since strain K3.22 effectively nodulated red and white clover but not vetch, in contrast to R. pisi DSM 30132(T), which effectively nodulated vetch but was not able to nodulate clover. Both strains had the ability to form nodules on pea and bean but they differed in bean cultivar specificity. The R. pisi K3.22 and DSM 30132(T) strains might provide evidence for the transfer of R. leguminosarum sv. trifolii and sv. viciae symbiotic plasmids occurring in natural soil populations. PMID:23507586

Marek-Kozaczuk, Monika; Leszcz, Agnieszka; Wielbo, Jerzy; Wdowiak-Wróbel, Sylwia; Skorupska, Anna

2013-06-01

113

Sobrevivência e nodulação do Rhizobium tropici em sementes de feijão tratadas com fungicidas / Survival and nodulation of Rhizobium tropici on common bean seeds treated with fungicides  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo deste trabalho foi avaliar a sobrevivência e a capacidade de nodulação do Rhizobium tropici em sementes de feijão tratadas com fungicidas. O estudo foi realizado em laboratório e em casa de vegetação. Sementes de feijão (Phaseolus vulgaris) foram tratadas com seis diferentes fungicidas e [...] inoculadas com Rhizobium tropici estirpe CIAT 899. A sobrevivência do Rhizobium nas sementes foi avaliada no tempo 0 e 24 horas após o tratamento com fungicidas e a inoculação, utilizando o método do número mais provável (NMP). A nodulação do feijão, em plantio realizado no tempo 0 e 24 horas após o tratamento com fungicidas, e a inoculação foram avaliadas em solo com população estabelecida de Rhizobium nativo aos trinta dias após a emergência das plantas. A sobrevivência do Rhizobium inoculado nas sementes foi prejudicada pela aplicação dos fungicidas avaliados. A nodulação do feijoeiro foi reduzida pela aplicação dos fungicidas, quando o plantio foi realizado 24 horas após o tratamento das sementes. Entretanto, foram encontrados nódulos em todos os tratamentos, evidenciando que houve nodulação do Rhizobium nativo do solo. Abstract in english The aim of this work was to evaluate the survival and nodulation of Rhizobium tropici on common bean seeds treated with fungicides. The study was conduced out at laboratory and greenhouse conditions. Common bean (Phaseolus vulgaris) seeds were treated with six fungicides and inoculated with Rhizobiu [...] m tropici strain CIAT 899. The survival of Rhizobium on seeds was evaluated 0 and 24 hours after treatment with fungicides and inoculation, using the most probable number (MPN) method. The nodulation of common bean thirty days after plant emergence, in plantation conduced 0 and 24 hours after seeds treatment with fungicides and inoculation, was evaluated in soil with population of native Rhizobium. The fungicides harmed the survival of inoculated Rhizobium on seeds and, in plantation conduced 24 hours after seeds treatment, reduced the nodulation of common bean. However, nodules were found in all plants, suggesting nodulation by native Rhizobium of soil.

Ademir Sérgio Ferreira de, Araújo; Ricardo Silva, Araújo.

114

Determining the parameters of the Minimal Supergravity Model from 2l + $E_T ^{miss}$ + (jets) final states at LHC  

CERN Multimedia

We analyse the events with two same-flavour, opposite-sign leptons + $E_T^{miss}$ + (jets) as expected in pp collisions at LHC within the framework of the minimal Supergravity Model. The objective is the determination of the parameters m_0 and m_{1/2} of this model (for a given value of $\\tan\\beta$). The signature $l^+ l^- + E_T^{miss}$ + (jets) selects the leptonic decays of $\\tilde{\\chi}^0_2$, $\\tilde{\\chi}^0_2 \\to \\tilde{\\chi}^0_1 l^+ l^- $, $\\tilde{\\chi}^0_2 \\to \\tilde{l}_{L,R}^{\\pm} l^{\\mp} \\to \\tilde{\\chi}^0_1 l^+ l^-$. We exploit the fact that the invariant dilepton mass distribution has a pronounced structure with a sharp edge at the kinematical endpoint even in such an inclusive final state over a significant part of parameter space. We determine the domain of parameter space where the edge is expected to be visible. We show that a measurement of this edge already constrains the model parameters essentially to three lines in the ($m_0, m_{1/2}$) parameter plane. We work out a strategy to discriminate...

Denegri, Daniel; Rurua, Lali

1997-01-01

115

Rhizobium strains competitiveness on bean nodulation in Cerrado soils Capacidade competitiva de estirpes de Rhizobium na nodulação do feijoeiro em solos de Cerrado  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this work was to identify the most competitive and effective Rhizobium strains in order to increase common bean yield by nitrogen fixation as alternative or complementation to the nitrogen fertilization. Competitiveness tests were lead in axenic conditions, in Cerrado soil pots and in three field experiments, with native Rhizobium strains that were previously identified, according to their effectiveness and genetic variability. The identification of strains in nodules was per...

Ruy Raposeiras; Ivanildo Evódio Marriel; Maria Rita Scotti Muzzi; Edilson Paiva; Israel Alexandre Pereira Filho; Lilia Costa Carvalhais; Raul Vinícius Magalhães Passos; Patrícia Pereira Pinto; Nadja Maria Horta de Sá

2006-01-01

116

Contribution of the Rhizobium Inoculation on Plant Growth and Productivity of Two Cultivars of Berseem (Trifolium alexandrinum L. in Saline Soil  

Directory of Open Access Journals (Sweden)

Full Text Available The present study was undertaken on the interactive effect of Rhizobium seed culture treatment and saline irrigation on the plant growth and productivity (fodder/biological yield in two cultivars (WARDAN and BB 2 of berseem. The experiment was conducted following completely randomized block design method considering three replicates and data were subjected to statistical analysis of variance using three factorial randomized design method. Two sets of plots were maintained in which one set contained non-inoculated while another set contained inoculated seeds with Rhizobium culture, which were irrigated with saline waters of different electrical conductivities (0, 3, 6, 7.2, 10, 12 and 14 dS m-1. The observations were recorded at two durations i.e., 90 and 120 DAS. The plant growth has been enhanced at lower levels of salinity (3 to 7.2 dS m-1 and invariably inhibited at 10 dS m-1 and beyond. Inoculation with Rhizobium culture had expressed synergistic effects on growth and productivity at both durations particularly at lower EC levels and also minimized the deleterious effect of salinity at 10 to 14 dS m-1 to some extent. The yield characteristics (biological and fodder yield had been differentially affected in berseem. Cv. WARDAN had registered maximum yield at the final harvest in Rhizobium inoculated sets at 3, 6 and 7.2 dS m-1. Similar findings were recorded for total green and dry weight fodder yield/plot (kg m-2. Our findings proves that cv. WARDAN might be tried on saline soils to obtain some biomass.

S. Agarwal

2010-01-01

117

Relations between Rhizobium and radiostimulation treatments of seeds  

International Nuclear Information System (INIS)

In field experiments the effects of irradiation with "6"0Co isotope the seeds of round seeded peas (Pisum sativum L.), beans (Phaseolus vulgaris L.), soybeans (Glycine max. L./Merr.) and lucerne (Medicago sativa) were investigated. Rhizobium bacteria inoculation was carried out with the inoculator ''Rhizonit''. The green mass yield was determined for lucerne and the grain yield for the other plants. Irradiation induced flowering of peas 4-5 days earlier. The bean yields increased significantly on the influence of 1000 rad irradiation plus Rhizonit inoculation. For soybeans the yield response to Rhizonit proved to be significant. (author)

1979-03-16

118

Biochemical characterization of a fructokinase mutant of Rhizobium meliloti.  

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A double mutant strain (UR3) of Rhizobium meliloti L5-30 was isolated from a phosphoglucose isomerase mutant (UR1) on the basis of its resistance to fructose inhibition when grown on fructose-rich medium. UR3 lacked both phosphoglucose isomerase and fructokinase activity. A mutant strain (UR4) lacking only the fructokinase activity was derived from UR3; it grew on the same carbon sources as the parent strain, but not on fructose, mannitol, or sorbitol. A spontaneous revertant (UR5) of normal ...

Gardiol, A.; Arias, A.; Cerven?ansky, C.; Gaggero, C.; Marti?nez-drets, G.

1980-01-01

119

Cloning and mutagenesis of the Rhizobium meliloti isocitrate dehydrogenase gene.  

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The gene encoding Rhizobium meliloti isocitrate dehydrogenase (ICD) was cloned by complementation of an Escherichia coli icd mutant with an R. meliloti genomic library constructed in pUC18. The complementing DNA was located on a 4.4-kb BamHI fragment. It encoded an ICD that had the same mobility as R. meliloti ICD in nondenaturing polyacrylamide gels. In Western immunoblot analysis, antibodies raised against this protein reacted with R. meliloti ICD but not with E. coli ICD. The complementing...

Mcdermott, T. R.; Kahn, M. L.

1992-01-01

120

Effect of Salinity on Rhizobium Growth and Survival †  

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This study examines the effect of salinity on the growth and survival of Rhizobium spp. in culture media and soil. Eleven isolates from saline and nonsaline environments were compared. The growth (mean doubling time) of all strains and species tested decreased when the electrical conductivity of the culture medium (yeast extract-mannitol) was raised from 1.2 mS cm?1 to 6.7 mS cm?1 (15% seawater equivalent) or to 13.1 mS cm?1 (28% seawater equivalent). Three of eleven strains failed to g...

Singleton, P. W.; El Swaify, S. A.; Bohlool, B. B.

1982-01-01

 
 
 
 
121

Effects of iron deficiency on heme biosynthesis in Rhizobium japonicum.  

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The effects of iron deficiency on heme biosynthesis in Rhizobium japonicum were examined. Iron-deficient cells had a decreased maximum cell yield and a decreased cytochrome content and excreted protoporphyrin into the growth medium. The activities of the first two enzymes of heme biosynthesis, delta-aminolevulinic acid synthase (EC 2.3.1.37) and delta-aminolevulinic acid dehydrase (EC 4.2.1.24), were diminished in iron-deficient cells, but were returned to normal levels upon addition of iron ...

Roessler, P. G.; Nadler, K. D.

1982-01-01

122

Characterization of Rhizobium loti strains from the Salado River Basin.  

Science.gov (United States)

Thirty indigenous rhizobia strains, isolated from Lotus tenuis in the area of Chascomús and other regions of the Salado River Basin (Argentina), were characterized based on generation time, acid production, carbon utilization, protein profile, and molecular characterization by restriction fragment length polymorphism (RFLP) analysis of 16S rRNA genes amplified by the polymerase chain reaction (PCR). The results indicated that native rhizobia isolates from the Chascomús area are predominantly fast and intermediate-growers. The unclassified rhizobia examined by PCR-RFLP were found to be closely related to the reference strains of validly described Rhizobium species. PMID:11519997

Fulchieri, M M; Estrella, M J; Iglesias, A A

2001-06-01

123

Suicide plasmid vehicles for insertion mutagenesis in Rhizobium meliloti and related bacteria.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe the construction and use of a set of plasmid vectors of the transposons Tn1, Tn5, and Tn9 that are suicidal in Rhizobium species and therefore suitable for mutagenesis with these three transposons. The vectors are composed of the p15A replicon which functions in Escherichia coli but not in Rhizobium species and a region encoding the N type of bacterial conjugation system which is very efficient in matings between E. coli and Rhizobium species. The usefulness of the vectors has bee...

Selvaraj, G.; Iyer, V. N.

1983-01-01

124

Role of Rhizobium Inoculation in Chickpea (Cicer arietinum L. Under Water Stress Conditions  

Directory of Open Access Journals (Sweden)

Full Text Available Two chickpea varieties viz., 90122 and 93081 were subjected to Rhizobium inoculation with BioPower under water stress conditions, imposed by withholding water. Stress reduced all the parameters including yield components and this effect was more pronounced by stress at reproductive stage as compared with vegetative stage. Rhizobium inoculation enhanced yield under both normal and stressed conditions, but its performance was better under normal than under stress. Rhizobium inoculation proved ineffective to recover loss caused by water stress. The two varieties exhibited statistically non-significant differences.

Rahat Parveen

1999-01-01

125

studies On Legume-rhizobium And Mycorrihizal Interaction Withspecial Reference To Phaseolusradiatusl. And Phaseolus Aconitifoliusjacq.  

Directory of Open Access Journals (Sweden)

Full Text Available The study was initiated to determine the influence of VAM fungi on a Rhizobium- legume interaction. The pot culture experiment was conducted during rabbi season with seed of Phaseolu sradiatus.L.and PhaseolusaconitifoliusJacq.and Leonard jar experiment was conducted for Phaseolusa conitifolius.The different inoculations of Rhizobium and Mycorrihizawere incorporated. During the period of experiment, samples were analysed for nodule numbers, dry weight of nodules,freshweight, dry weight of plant, yield of pods, and length of plant and percentage of Mycorrihizalcolonization. The results revealed that dual inoculation of Rhizobium with VAM enhanced seed yield of chickpea and golden- green gram.

Sunil A. Gosavi

2013-08-01

126

Antimicrobial activity of Rhizobium sp. strains against Pseudomonas savastanoi, the agent responsible for the olive knot disease in Algeria  

Directory of Open Access Journals (Sweden)

Full Text Available In the present investigation, six Rhizobium strains isolated from Algerian soil were checked for their antimicrobial activity against Pseudomonas savastanoi, the agent responsible for olive knot disease. Rhizobium sp. ORN 24 and ORN 83 were found to produce antimicrobial activities against Pseudomonas savastanoi. The antimicrobial activity produced by Rhizobium sp. ORN24 was precipitable with ammonium sulfate, between 1,000 and 10,000 KDa molecular weight, heat resistant but sensitive to proteases and detergents. These characteristics suggest the bacteriocin nature of the antimicrobial substance produced by Rhizobium sp. ORN24, named rhizobiocin 24. In contrast, the antimicrobial activity produced by Rhizobium sp. ORN83 was not precipitable with ammonium sulfate; it was smaller than 1,000 KDa molecular weight, heat labile, and protease and detergent resistant. These characteristics could indicate the relationship between the antimicrobial substance produced by Rhizobium sp. ORN 83 and the “small” bacteriocins described in other rhizobia.

En la presente investigación, seis cepas de Rhizobium aisladas de suelos argelinos fueron estudiadas para conocer su actividad antimicrobiana contra Pseudomonas savastanoi, el agente causante de la tuberculosis del olivo. Rhizobium sp. ORN 24 y ORN 83 produjeron actividad antimicrobiana contra Pseudomonas savastanoi. La actividad antimicrobiana producida por Rhizobium sp. ORN 24 precipitó con sulfato amónico, tuvo un peso molecular entre 1000 y 10000 KDa, fue resistente al calor pero sensible a proteasas y detergentes. Estas características sugieren que la sustancia antimicrobial producida por Rhizobium sp. ORN 24 es la bacteriocina natural conocida como rizobiocina 24. Por el contrario, la actividad antimicrobiana producida por Rhizobium sp. ORN83 no fue precipitable con sulfato amónico, y tuvo un peso molecular menor de 1000 KDa, fue lábil al calor y resistente a detergentes y proteasas. Estas características podrían indicar una relación de la sustancia antimicrobiana producida por Rhizobium sp. ORN83 con la “pequeña” bacteriocina descrita en otros Rhizobium.

2009-06-01

127

Ação de herbicidas sobre o crescimento de estirpes de Rhizobium tropici / Herbicide action on the growth of Rhizobium tropici strains  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo deste trabalho foi avaliar o crescimento das estirpes de Rhizobium tropici BR 322 e BR 520, utilizadas como inoculantes na cultura do feijoeiro no Brasil, em meio de cultura à base de manitol e extrato de levedura (YM) adicionado de diferentes herbicidas (bentazon, metolachlor, imazamox, [...] fluazifop-p-butil, fomesafen e paraquat). Os herbicidas fluazifop-p-butil e fomesafen foram avaliados puros e em mistura comercial, em concentrações variando entre 0,0 e 49,23 mg L-1. O crescimento das estirpes de Rhizobium foi avaliado em espectrofotômetro ao longo de 100 horas de incubação, por meio da leitura da densidade ótica, a 560 nm, sendo, posteriormente, convertido em unidades formadoras de colônia por mL. Observou-se que o paraquat foi o herbicida com maior inibição do crescimento das estirpes avaliadas, seguido pela mistura comercial de fomesafen e fluazifop-p-butil. Para os demais herbicidas, a redução do crescimento não foi significativa. De modo geral, a estirpe BR 520 mostrou-se mais tolerante aos herbicidas testados, com exceção do paraquat. No ensaio de concentrações crescentes do fomesafen, isolado ou em mistura com fluazifop-p-butil, não foi possível determinar o I50 (concentração do herbicida que reduz em 50% o crescimento do rizóbio); a maior redução, de 31,1%, foi observada para a estirpe BR 322 na máxima concentração testada (49,23 mg L-1) da mistura comercial. Abstract in english This work aimed to evaluate the growth of Rhizobium tropici BR322 and BR 520 strains, used as inoculant on common bean in Brazil, in yeast extract manitol (YM) medium supplemented with different herbicides (bentazon, metolachlor, imazamox, fluazifop-p-butyl, fomesafen and paraquat). Fluazifop-p-buty [...] l and fomesafen were evaluated pure and in a commercial mixture with concentration varying from 0.0 to 49.23 mg L-1. Cell growth was assessed by optic density readings in a spectrophotometer at 560 nm, being later converted to colony forming units per mL. Paraquat caused higher inhibition of cell growth, followed by the commercial mixture fomesafen and fluazifop-p-butyl. For the other herbicides, growth reduction was not significant. In general, BR 520 strain was more tolerant to the tested herbicides, except to paraquat. The herbicide concentration I50, (which decreased Rhizobium growth in 50%) could not be determined in the fomesafen concentrations tested, isolated or mixed to fluazifop-p-butyl. The highest reduction of 31.1% was observed in BR322 at the maximum tested concentration of the commercial mixture.

J.B., Santos; A.A., Silva; M.D., Costa; A., Jakelaitis; R., Vivian; E.A., Santos.

128

Ação de herbicidas sobre o crescimento de estirpes de Rhizobium tropici Herbicide action on the growth of Rhizobium tropici strains  

Directory of Open Access Journals (Sweden)

Full Text Available O objetivo deste trabalho foi avaliar o crescimento das estirpes de Rhizobium tropici BR 322 e BR 520, utilizadas como inoculantes na cultura do feijoeiro no Brasil, em meio de cultura à base de manitol e extrato de levedura (YM adicionado de diferentes herbicidas (bentazon, metolachlor, imazamox, fluazifop-p-butil, fomesafen e paraquat. Os herbicidas fluazifop-p-butil e fomesafen foram avaliados puros e em mistura comercial, em concentrações variando entre 0,0 e 49,23 mg L-1. O crescimento das estirpes de Rhizobium foi avaliado em espectrofotômetro ao longo de 100 horas de incubação, por meio da leitura da densidade ótica, a 560 nm, sendo, posteriormente, convertido em unidades formadoras de colônia por mL. Observou-se que o paraquat foi o herbicida com maior inibição do crescimento das estirpes avaliadas, seguido pela mistura comercial de fomesafen e fluazifop-p-butil. Para os demais herbicidas, a redução do crescimento não foi significativa. De modo geral, a estirpe BR 520 mostrou-se mais tolerante aos herbicidas testados, com exceção do paraquat. No ensaio de concentrações crescentes do fomesafen, isolado ou em mistura com fluazifop-p-butil, não foi possível determinar o I50 (concentração do herbicida que reduz em 50% o crescimento do rizóbio; a maior redução, de 31,1%, foi observada para a estirpe BR 322 na máxima concentração testada (49,23 mg L-1 da mistura comercial.This work aimed to evaluate the growth of Rhizobium tropici BR322 and BR 520 strains, used as inoculant on common bean in Brazil, in yeast extract manitol (YM medium supplemented with different herbicides (bentazon, metolachlor, imazamox, fluazifop-p-butyl, fomesafen and paraquat. Fluazifop-p-butyl and fomesafen were evaluated pure and in a commercial mixture with concentration varying from 0.0 to 49.23 mg L-1. Cell growth was assessed by optic density readings in a spectrophotometer at 560 nm, being later converted to colony forming units per mL. Paraquat caused higher inhibition of cell growth, followed by the commercial mixture fomesafen and fluazifop-p-butyl. For the other herbicides, growth reduction was not significant. In general, BR 520 strain was more tolerant to the tested herbicides, except to paraquat. The herbicide concentration I50, (which decreased Rhizobium growth in 50% could not be determined in the fomesafen concentrations tested, isolated or mixed to fluazifop-p-butyl. The highest reduction of 31.1% was observed in BR322 at the maximum tested concentration of the commercial mixture.

J.B. Santos

2006-09-01

129

Ação de herbicidas sobre o crescimento de estirpes de Rhizobium tropici Herbicide action on the growth of Rhizobium tropici strains  

Digital Repository Infrastructure Vision for European Research (DRIVER)

O objetivo deste trabalho foi avaliar o crescimento das estirpes de Rhizobium tropici BR 322 e BR 520, utilizadas como inoculantes na cultura do feijoeiro no Brasil, em meio de cultura à base de manitol e extrato de levedura (YM) adicionado de diferentes herbicidas (bentazon, metolachlor, imazamox, fluazifop-p-butil, fomesafen e paraquat). Os herbicidas fluazifop-p-butil e fomesafen foram avaliados puros e em mistura comercial, em concentrações variando entre 0,0 e 49,23 mg L-1. O crescime...

2006-01-01

130

A rhizobium leguminosarum mutant defective in symbiotic iron acquisition  

International Nuclear Information System (INIS)

Iron acquisition by symbiotic Rhizobium spp. is essential for nitrogen fixation in the legume root nodule symbiosis. Rhizobium leguminosarum 116, an ineffective mutant strain with a defect in iron acquisition, was isolated after nitrosoguanidine mutagenesis of the effective strain 1062. The pop-1 mutation in strain 116 imparted to it a complex phenotype, characteristic of iron deficiency. Several iron(III)-solubilizing agents, such as citrate, hydroxyquinoline, and dihydroxybenzoate, stimulated growth of 116 on low-iron solid medium; anthranilic acid, the R. leguminosarum siderophore, inhibited low-iron growth of 116. The initial rate of 55Fe uptake by suspensions of iron-starved 116 cells was 10-fold less than that of iron-starved wild-type cells. Electron microscopic observations revealed no morphological abnormalities in the small, white nodules induced by 116. Nodule cortical cells were filled with vesicles containing apparently normal bacteroids. No premature degeneration of bacteroids or of plant cell organelles was evident. The authors mapped pop-1 by R plasmid-mediated conjugation and recombination to the ade-27-rib-2 region of the R. leguminosarum chromosome. No segregation of pop-1 and the symbiotic defect was observed among the recombinants from these crosses. Cosmid pKN1, a pLAFR1 derivative containing a 24-kilobase-pair fragment of R. leguminosarum DNA, conferred on 116 the ability to grow on dipyridyl medium and to fix nitrogen symbiotically

1990-01-01

131

Microgravity effects on the legume/Rhizobium symbiosis  

Science.gov (United States)

Symbiotic nitrogen fixation is of critical importance to world agriculture and likely will be a critical part of life support systems developed for prolonged missions in space. Bacteroid formation, an essential step in an effective Dutch White Clover/Rhizobium leguminosarum bv trifolii symbiosis, is induced by succinic acid which is produced by the plant and which is bound and incorporated by the bacterium. Aspirin mimics succinate in its role as a bacteroid inducer and measures of aspirin binding mimiced measurements of succinate binding. In normal gravity (1×g), rhizobium bacteria immediately bound relatively high levels of aspirin (or succinate) in a readily reversible manner. Within a few seconds a portion of this initially bound aspirin became irreversibly bound. In the microgravity environment aboard the NASA 930 aircraft, rhizobia did not display the initial reversible binding of succinate, but did display a similar kinetic pattern of irreversible binding, and ultimately bound 32% more succinate (Acta Astronautica 36:129-133, 1995.) In normal gravity succinate treated cells stop dividing and swell to their maximum size (twice the normal cell volume) within a time equivalent to the time required for two normal cell doublings. Swelling in microgravity was tested in FPA and BPM sample holders aboard the space shuttle (USML-1, and STS-54, 57, and 60.) The behavior of cells in the two sample holders was similar, and swelling behavior of cells in microgravity was identical to behavior in normal gravity.

Urban, James E.

1997-01-01

132

ETS Applications  

...and GuidanceETS ApplicationsETS Emission...Transfer RegisterETS ApplicationsLast updated...application, the monitoring & reporting plan or subsequent variation applications should be notified to IPRI. This includes administrative...

133

Nitrogen fixing capacity of some soybean cultivars inoculated with different Rhizobium japonicum strains  

International Nuclear Information System (INIS)

The nitrogen-fixing efficiency of different Rhizobium japonicum strains was tested. The strains were inoculated into three soybean cultivars and grain yield, total nitrogen content and nitrogen-fixing capacity were determined. 4 refs, 1 tab

1990-10-01

134

Antimicrobial activities of Rhizobium sp. strains against Pseudomonas savastanoi, the agent responsible for the olive knot disease in Algeria  

Energy Technology Data Exchange (ETDEWEB)

In the present investigation, six Rhizobium strains isolated from Algerian soil were checked for their antimicrobial activity against Pseudomonas savastanoi, the agent responsible for olive knot disease. Rhizobium sp. ORN 24 and ORN 83 were found to produce antimicrobial activities against Pseudomonas savastanoi. The antimicrobial activity produced by Rhizobium sp. ORN24 was precipitable with ammonium sulfate, between 1,000 and 10,000 KDa molecular weight, heat resistant but sensitive to proteases and detergents. These characteristics suggest the bacteriocin nature of the antimicrobial substance produced by Rhizobium sp. ORN24, named rhizobiocin 24. In contrast, the antimicrobial activity produced by Rhizobium sp. ORN83 was not precipitable with ammonium sulfate; it was smaller than 1,000 KDa molecular weight, heat labile, and protease and detergent resistant. These characteristics could indicate the relationship between the antimicrobial substance produced by Rhizobium sp. ORN 83 and the small bacteriocins described in other rhizobia. (Author) 51 refs.

Mourad, K.; Fadhila, K.; Chahinez, M.; Merien, R.; Philippe, L. de; Abdelkader, B.

2009-07-01

135

Genome sequence of the acid-tolerant strain Rhizobium sp. LPU83.  

Science.gov (United States)

Rhizobia are important members of the soil microbiome since they enter into nitrogen-fixing symbiosis with different legume host plants. Rhizobium sp. LPU83 is an acid-tolerant Rhizobium strain featuring a broad-host-range. However, it is ineffective in nitrogen fixation. Here, the improved draft genome sequence of this strain is reported. Genome sequence information provides the basis for analysis of its acid tolerance, symbiotic properties and taxonomic classification. PMID:24556327

Wibberg, Daniel; Tejerizo, Gonzalo Torres; Del Papa, María Florencia; Martini, Carla; Pühler, Alfred; Lagares, Antonio; Schlüter, Andreas; Pistorio, Mariano

2014-04-20

136

Synthesis of glycerophosphorylated cyclic beta-(1,2)-glucans by Rhizobium meliloti ndv mutants.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The periplasmic cyclic beta-(1,2)-glucans of Rhizobium spp. are believed to provide functions during hypoosmotic adaptation and legume nodulation. In Rhizobium meliloti, cyclic beta-(1,2)-glucans are synthesized at highest levels when cells are grown at low osmolarity, and a considerable fraction (> or = 35%) of these glucans may become substituted with phosphoglycerol moieties. Thus far, two chromosomally encoded proteins, NdvA and NdvB, have been shown to function during cyclic beta-(1,2)-g...

Breedveld, M. W.; Yoo, J. S.; Reinhold, V. N.; Miller, K. J.

1994-01-01

137

Effect of Rhizobium sp., on Growth of Pathogenic Fungi under in vitro Conditions  

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Full Text Available In a laboratory study chickpea root nodulating bacterium Rhizobium sp., strain Thal-8 significantly inhibited the growth of pathogenic fungi (Alternaria alternata, Fusarium sp. Ascochyta rabiei, Drechslera sp. and Curvularia sp. in potato dextrose agar media. The inhibition rate displayed differences in accordance with different fungi cultures. However, the inhibitory effect of Rhizobium sp., strain Thal-8 occurred most on pure cultures growth of Alternaria alternata and Drechslera sp. (54 and 45%, respectively and least on Curvularia sp. (3%.

Tabassam Sharif

2003-01-01

138

Rhizobium as a Biological Agent for Preventing Heavy Metal Stress  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present study, Rhizobium was used as soil fertilizer to prevent the stress of lead on growing Pisum sativum. Three concentrations of lead were used (50, 100 and 200 ppm.) for the irrigation of growing plants (two times). After sowing, M2 seeds were collected, then cytological and biochemical studies were carried out. The cytological analysis revealed that soil enriched with Rhizobium increased the rate of mitotic division. A significant increase in mitot...

Abbas, S. M.; Kamel, E. A.

2004-01-01

139

The central domain of Rhizobium leguminosarum DctD functions independently to activate transcription.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sigma 54-dependent transcriptional activators such as Escherichia coli NtrC, Rhizobium meliloti NifA, and Rhizobium leguminosarum DctD share similar central and carboxy-terminal domains but differ in the structure and function of their amino-terminal domains. We have deleted the amino-terminal and carboxy-terminal domains of R. leguminosarum DctD and have demonstrated that the central domain of DctD, like that of NifA, is transcriptionally competent.

Huala, E.; Stigter, J.; Ausubel, F. M.

1992-01-01

140

Energy supply for dinitrogen fixation by Azotobacter vinelandii and by bacteroids of Rhizobium leguminosarum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The central issue of this thesis is how obligate aerobes, such as Rhizobium leguminosarum bacteroids and Azotobacter vinelandii, generate and regulate the energy supply (in the form of ATP and reducing equivalents) for nitrogenase.In an effective Rhizobium -legume symbiosis, the actual reduction of dinitrogen into ammonia is carried out in the root nodules by bacteroids. In order to study this intriguing process on the level of the bacteroids, it is clear that bacteroids have to be isolated ...

Laane, N. C. M.

1980-01-01

 
 
 
 
141

Dilution of Liquid Rhizobium Cultures To Increase Production Capacity of Inoculant Plants †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Experiments were undertaken to test whether peat-based legume seed inoculants, which are prepared with liquid cultures that have been deliberately diluted, can attain and sustain acceptable numbers of viable rhizobia. Liquid cultures of Rhizobium japonicum and Rhizobium phaseoli were diluted to give 108, 107, or 106 cells per ml, using either deionized water, quarter-strength yeast-mannitol broth, yeast-sucrose broth, or yeast-water. The variously diluted cultures were incorporated into gamma...

1982-01-01

142

Exopolysaccharide-Deficient Mutants of Rhizobium fredii HH303 Which Are Symbiotically Effective  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nineteen Tn5-induced mutants of Rhizobium fredii HH303 defective in acidic exopolysaccharide synthesis were isolated by screening for lack of Calcofluor fluorescence. They were grouped by complementation analysis by using Rhizobium meliloti cosmids carrying exo genes. All of the 19 mutants were symbiotically effective or partially effective, indicating that the major bacterial acidic exopolysaccharide of this strain of R. fredii may not be required for symbiotic development in the soybean.

Kim, Choong-hyun; Tully, Raymond E.; Keister, Donald L.

1989-01-01

143

Perception of Rhizobium nodulation factors by tomato cells and inactivation by root chitinases.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The bacterial genera Rhizobium and Bradyrhizobium, nitrogen-fixing symbionts of legumes, secrete specific lipo-chitooligosaccharides that induce the formation of nodules on their host plants. When preparations of such nodulation-inducing factors (Nod factors) were added to suspension-cultured tomato cells, a rapid and transient alkalinization of the culture medium occurred. Lipo-oligosaccharide preparations from Rhizobium or Bradyrhizobium treated with flavonoids, known inducers of Nod factor...

Staehelin, C.; Granado, J.; Mu?ller, J.; Wiemken, A.; Mellor, R. B.; Felix, G.; Regenass, M.; Broughton, W. J.; Boller, T.

1994-01-01

144

Genodiversity of dominant Rhizobium leguminosarum bv. Trifolii isolated from 11 types of soil in Serbia  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rhizobium leguminosarum bv. trifolii is microsymbiont Trifolium pratense and Trifolium repens, which are very important legumes in Serbia. The natural nodulating population of those bacteria was collected and estimated biodiversity distribution by monitoring dominant genotypes of these bacteria. The population of Rhizobium leguminosarum bv. trifolii were collected from 50 marked locations of 11 types of soil in Serbia. 437 natural isolates, rescued from nodules of Trifolium repens or Trifoliu...

Joši? Dragana; Mili?i? Bogi?; Mladenovi?-Drini? Snežana; Jarak Mirjana

2008-01-01

145

Rhizobium leguminosarum Biovar viciae 1-Aminocyclopropane-1-Carboxylate Deaminase Promotes Nodulation of Pea Plants  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ethylene inhibits nodulation in various legumes. In order to investigate strategies employed by Rhizobium to regulate nodulation, the 1-aminocyclopropane-1-carboxylate (ACC) deaminase gene was isolated and characterized from one of the ACC deaminase-producing rhizobia, Rhizobium leguminosarum bv. viciae 128C53K. ACC deaminase degrades ACC, the immediate precursor of ethylene in higher plants. Through the action of this enzyme, ACC deaminase-containing bacteria can reduce ethylene biosynthesis...

Ma, Wenbo; Guinel, Fre?de?rique C.; Glick, Bernard R.

2003-01-01

146

Antimicrobial activity of Rhizobium sp. strains against Pseudomonas savastanoi, the agent responsible for the olive knot disease in Algeria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present investigation, six Rhizobium strains isolated from Algerian soil were checked for their antimicrobial activity against Pseudomonas savastanoi, the agent responsible for olive knot disease. Rhizobium sp. ORN 24 and ORN 83 were found to produce antimicrobial activities against Pseudomonas savastanoi. The antimicrobial activity produced by Rhizobium sp. ORN24 was precipitable with ammonium sulfate, between 1,000 and 10,000 KDa molecular weight, heat resistant but sensitive to prot...

Kacem, Mourad; Kazouz, Fadhila; Merabet, Chahinez; Rezki, Meriem; Lajudie, Philippe; Bekki, Abdelkader

2009-01-01

147

Role of Rhizobium Inoculation in Chickpea (Cicer arietinum L.) Under Water Stress Conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two chickpea varieties viz., 90122 and 93081 were subjected to Rhizobium inoculation with BioPower under water stress conditions, imposed by withholding water. Stress reduced all the parameters including yield components and this effect was more pronounced by stress at reproductive stage as compared with vegetative stage. Rhizobium inoculation enhanced yield under both normal and stressed conditions, but its performance was better under normal than under stress. Rhizobium inoculation proved i...

1999-01-01

148

Sobrevivência e nodulação do Rhizobium tropici em sementes de feijão tratadas com fungicidas  

Directory of Open Access Journals (Sweden)

Full Text Available O objetivo deste trabalho foi avaliar a sobrevivência e a capacidade de nodulação do Rhizobium tropici em sementes de feijão tratadas com fungicidas. O estudo foi realizado em laboratório e em casa de vegetação. Sementes de feijão (Phaseolus vulgaris foram tratadas com seis diferentes fungicidas e inoculadas com Rhizobium tropici estirpe CIAT 899. A sobrevivência do Rhizobium nas sementes foi avaliada no tempo 0 e 24 horas após o tratamento com fungicidas e a inoculação, utilizando o método do número mais provável (NMP. A nodulação do feijão, em plantio realizado no tempo 0 e 24 horas após o tratamento com fungicidas, e a inoculação foram avaliadas em solo com população estabelecida de Rhizobium nativo aos trinta dias após a emergência das plantas. A sobrevivência do Rhizobium inoculado nas sementes foi prejudicada pela aplicação dos fungicidas avaliados. A nodulação do feijoeiro foi reduzida pela aplicação dos fungicidas, quando o plantio foi realizado 24 horas após o tratamento das sementes. Entretanto, foram encontrados nódulos em todos os tratamentos, evidenciando que houve nodulação do Rhizobium nativo do solo.

Araújo Ademir Sérgio Ferreira de

2006-01-01

149

Rhizobium vallis sp. nov., isolated from nodules of three leguminous species.  

Science.gov (United States)

Four bacterial strains isolated from root nodules of Phaseolus vulgaris, Mimosa pudica and Indigofera spicata plants grown in the Yunnan province of China were identified as a lineage within the genus Rhizobium according to the analysis of 16S rRNA gene sequences, sharing most similarity with Rhizobium lusitanum P1-7(T) (99.1 % sequence similarity) and Rhizobium rhizogenes IAM 13570(T) (99.0 %). These strains also formed a distinctive group from the reference strains for defined species of the genus Rhizobium in a polyphasic approach, including the phylogenetic analyses of the 16S rRNA gene and housekeeping genes (recA, atpD, glnII), DNA-DNA hybridization, BOX-PCR fingerprinting, phenotypic characterization, SDS-PAGE of whole-cell proteins, and cellular fatty acid profiles. All the data obtained in this study suggested that these strains represent a novel species of the genus Rhizobium, for which the name Rhizobium vallis sp. nov. is proposed. The DNA G+C content (mol%) of this species varied between 60.9 and 61.2 (T(m)). The type strain of R. vallis sp. nov. is CCBAU 65647(T) ( = LMG 25295(T) =HAMBI 3073(T)), which has a DNA G+C content of 60.9 mol% and forms effective nodules on Phaseolus vulgaris. PMID:21131504

Wang, Fang; Wang, En Tao; Wu, Li Juan; Sui, Xin Hua; Li, Ying; Chen, Wen Xin

2011-11-01

150

Bouvard et Pécuchet et le désir amoureux  

Directory of Open Access Journals (Sweden)

Full Text Available L’article propose une étude de genèse du chapitre 7 de Bouvard et Pécuchet, consacré à l’amour, qui forme une étape encyclopédique a priori un peu surprenante. Flaubert s’amuse à écrire ces aventures de Bouvard et Pécuchet, dans un pays qui n’est pas si tendre. L’étude de genèse porte sur le travail de l’écriture de plusieurs temps forts du chapitre (dans l’incipit, et les scènes de duos, notamment la scène entre Mme Castillon et Gorgu. Elle permet de montrer l’effacement de détails érotiques, mais aussi du politique et de l’histoire, qui se trouvent condensés dans le texte final. Elle révèle aussi le rôle concerté de ce chapitre dans la construction du roman et l’itinéraire des personnages. Anodin en apparence, ce chapitre est emblématique d’une poétique fondée sur l’ellipse, et qui mêle le jeu et le sérieux.This article presents a textual genetics study of Bouvard et Pécuchet’s 7th chapter, about love, which appears to be a surprising encyclopedic stage of the novel. Flaubert has fun writing these adventures in a not so tender country. This genetics study focuses on the writing of several key moments of the chapter (in the beginning and the duo scenes, such as the one between Mme Castillon and Gorgu. It reveals the erasure of erotic details, as well as politics and history, which end up condensed in the final text. It also shows this chapter’s concerted role in the construction of the novel and the characters’ development. Apparently minor, this chapter is emblematic of a poetics founded on the ellipsis, mingling play and seriousness.

Anne Herschberg Pierrot

2010-09-01

151

Rhizobium meliloti and Rhizobium leguminosarum dctD gene products bind to tandem sites in an activation sequence located upstream of sigma 54-dependent dctA promoters.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Free-living rhizobia transport external C4-dicarboxylates to use as sole carbon sources, and uptake of these compounds is essential for nitrogen fixation by rhizobial bacteroids. In both Rhizobium leguminosarum and Rhizobium meliloti, the genes dctB and dctD are believed to form an ntrB/ntrC-like two-component system which regulates the synthesis of a C4-dicarboxylate transport protein encoded by dctA. Here we confirm the identity of sigma 54-dependent promoters previously hypothesized for th...

Ledebur, H.; Gu, B.; Sojda, J.; Nixon, B. T.

1990-01-01

152

Differences between strains of Rhizobium in sensitivity to canavanine  

International Nuclear Information System (INIS)

Four strains of rhizobia that nodulate canavanine-synthesizing legumes and four strains that nodulate noncanavanine-synthesizing legumes were tested for sensitivity to L-canavanine. The effect of canavanine on growth depends upon the strain of Rhizobium tested rather than the canavanine synthesizing capability of the host legume. In both groups of rhizobia, some strains were inhibited in growth by canavanine. Canavanine enhancement of growth was observed in rhizobia that nodulate noncanavanine-synthesizing legumes. Canavanine was found to enhance the incorporation of 3H-uridine and 3H-L-leucine into trichloroacetic acid insoluble fractions of starved cells of two strains of rhizobia tested. This demonstrated that under certain conditions, some rhizobia can detoxify canavanine and utilize it in synthetic processes

1977-01-01

153

Strain identification in Rhizobium by starch gel electrophoresis of isoenzymes  

DEFF Research Database (Denmark)

Sonieated extracts of rhizobia, especiaUy Rhizobium leguminosarum from pea and vetch, were run in horizontal starch gel electrophoresis in the cold. The rhizobia were grown on agar on a slime suppressing substrate of tryptone-yeast extract-CaCl2 with small amounts of mannitol, sorbitol and arabinose and other sugars as enzyme inducers. After electrophoresis the gels were separated into several slabs by a gel cutter. Each slab was stained for a particular enzyme. Among numerous enzyme systems tested we found useful variation in esterases (EC 3.1.1.1, EC 3.1.1.2), 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30), mannitol dehydrogenase (EC 1.1.1.67), and arabinose dehydrogenase (EC 1.1.1.46). It was possible to distinguish at least 7 different types of pea rhizobia among 16 strains isolated from one batch of 5 kg soil.

Engvild, Kjeld Christensen

1985-01-01

154

New nonsynthetic medium for Rhizobium culture production from wastes  

Energy Technology Data Exchange (ETDEWEB)

A nonsynthetic medium was formulated for replacement of mannitol fully by saccharified pea husk (Pisum sativum L.) and water hyacinth (Eichhornia crassipes) with Trichoderma viride QM 9414 and molasses. Yeast extract was partially replaced by proteolysed peak husk, water hyacinth, and mycelium of T. viride QM 9414 by boiling 4 hr with 5% (v/v) HCl. The rhizobial growth was equal in both standard yeast extract mannitol (YEM) and formulated nonsynthetic media. However, barring Rhizobium phaseoli (urid) E-6, the rhizobial counts in the non-synthetic medium were higher than the counts in YEM medium. In the fermentor, rhizobial growth was also almost equal to YEM medium. These results indicated that costly ingredients like mannitol and yeast extract can be replaced by hydrolysates of pea husk, water hyacinth, mycelium of T. viride, and molasses. 5 figures.

Gulati, S.L.

1979-09-01

155

Deoxyribonucleic Acid Homology and Taxonomy of Agrobacterium, Rhizobium, and Chromobacterium  

Science.gov (United States)

Hybridization experiments were carried out between high molecular weight, denatured, agar-embedded deoxyribonucleic acid (DNA) and homologous, nonembedded, sheared, denatured 14C-labeled DNA from a strain of Agrobacterium tumefaciens and Rhizobium leguminosarum (the reference strains) in the presence of sheared, nonembedded, nonlabeled DNA (competing DNA) from the same or different nomen-species of Agrobacterium, Rhizobium, Chromobacterium, and several other organisms. Percentage of DNA homology was calculated from the results. The findings are discussed in relation to previous taximetric studies, present classification schemes, and guanine-cytosine content of the DNA. Strains of A. tumefaciens, A. radiobacter, A. rubi, A. rhizogenes, R. leguminosarum, and R. meliloti exhibited a mean percentage of DNA homology greater than 50 with the two reference strains. A. tumefaciens, A. radiobacter, and A. rubi were indistinguishable on the basis of DNA homology, with strain variations for this group involving up to 30% of their base sequences. The remainder of the organisms studied fall into at least six distinct genetic groups: (i) R. (Agrobacterium) rhizogenes, which is more homologous to R. leguminosarum than to the A. tumefaciens-A. radiobacter group; (ii) R. leguminosarum; (iii) R. meliloti; (iv) R. japonicum, which has a mean DNA homology of some 38 to 45% with the reference strains; (v) Chromobacterium, which is as genetically remote from the reference strains as, for example, Pseudomonas; and (vi) A. pseudotsugae strain 180, which has a DNA homology with A. tumefaciens and R. leguminosarum of only about 10%. Since this latter homology value is similar to what was found after hybridizations between the reference strains and organisms such as Escherichia coli and Bacillus subtilis, A. pseudotsugae should definitely be removed from the genus.

Heberlein, Gary T.; De Ley, J.; Tijtgat, R.

1967-01-01

156

Characterization of the nodulation plasmid encoded chemoreceptor gene mcpG from Rhizobium leguminosarum  

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Abstract Background 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. Results A putative methyl accepting chemotaxis protein gene (mcpG) of Rhizobium leguminosarum VF39SM was isolated and characterized. The gene was ...

Yost Christopher K; Clark Kirsten T; Del Bel Kate L; Hynes Michael F

2003-01-01

157

Oxamate is an alternative substrate for pyruvate carboxylase from Rhizobium etli.  

Science.gov (United States)

Oxamate, an isosteric and isoelectronic inhibitory analogue of pyruvate, enhances the rate of enzymatic decarboxylation of oxaloacetate in the carboxyl transferase domain of pyruvate carboxylase (PC). It is unclear, though, how oxamate exerts a stimulatory effect on the enzymatic reaction. Herein, we report direct (13)C nuclear magnetic resonance (NMR) evidence that oxamate acts as a carboxyl acceptor, forming a carbamylated oxamate product and thereby accelerating the enzymatic decarboxylation reaction. (13)C NMR was used to monitor the PC-catalyzed formation of [4-(13)C]oxaloacetate and subsequent transfer of (13)CO(2) from oxaloacetate to oxamate. In the presence of oxamate, the apparent K(m) for oxaloacetate is artificially suppressed (from 15 to 4-5 ?M). Interestingly, the steady-state kinetic analysis of the initial rates determined at varying concentrations of oxaloacetate and fixed concentrations of oxamate revealed initial velocity patterns inconsistent with a simple ping-pong-type mechanism. Rather, the patterns suggest the existence of an alternate decarboxylation pathway in which an unstable intermediate is formed. The steady-state kinetic analysis coupled with the normal (13)(V/K) kinetic isotope effect observed on C-4 of oxaloacetate [(13)(V/K) = 1.0117 ± 0.0005] indicates that the transfer of CO(2) from carboxybiotin to oxamate is the partially rate-limiting step of the enzymatic reaction. The catalytic mechanism proposed for the carboxylation of oxamate is similar to that proposed for the carboxylation of pyruvate, which occurs via the formation of an enol intermediate. PMID:23560609

Marlier, John F; Cleland, W W; Zeczycki, Tonya N

2013-04-30

158

Rhizobium grahamii sp. nov., from nodules of Dalea leporina, Leucaena leucocephala and Clitoria ternatea, and Rhizobium mesoamericanum sp. nov., from nodules of Phaseolus vulgaris, siratro, cowpea and Mimosa pudica.  

Science.gov (United States)

Two novel related Rhizobium species, Rhizobium grahamii sp. nov. and Rhizobium mesoamericanum sp. nov., were identified by a polyphasic approach using DNA-DNA hybridization, whole-genome sequencing and phylogenetic and phenotypic characterization including nodulation of Leucaena leucocephala and Phaseolus vulgaris (bean). As similar bacteria were found in the Los Tuxtlas rainforest in Mexico and in Central America, we suggest the existence of a Mesoamerican microbiological corridor. The type strain of Rhizobium grahamii sp. nov. is CCGE 502(T) (= ATCC BAA-2124(T) = CFN 242(T) = Dal4(T) = HAMBI 3152(T)) and that of Rhizobium mesoamericanum sp. nov. is CCGE 501(T) (= ATCC BAA-2123(T) = HAMBI 3151(T) = CIP 110148(T) = 1847(T)). PMID:22081714

López-López, Aline; Rogel-Hernández, Marco A; Barois, Isabelle; Ortiz Ceballos, Angel I; Martínez, Julio; Ormeño-Orrillo, Ernesto; Martínez-Romero, Esperanza

2012-09-01

159

Genome Sequence of Rhizobium grahamii CCGE502, a Broad-Host-Range Symbiont with Low Nodulation Competitiveness in Phaseolus vulgaris  

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Here we present the genome sequence of Rhizobium grahamii CCGE502. R. grahamii groups with other newly described broad-host-range species, which are not very efficient Phaseolus vulgaris symbionts, with a wide geographic distribution and which constitutes a novel Rhizobium clade.

Althabegoiti, M. Julia; Lozano, Luis; Torres-tejerizo, Gonzalo; Ormen?o-orrillo, Ernesto; Rogel, Marco A.; Gonza?lez, Vi?ctor; Marti?nez-romero, Esperanza

2012-01-01

160

Interacción micorriza vesiculo-arbuscular, Rhizobium leguminosa en un oxisol de los Llanos Orientales de Colombia  

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Full Text Available En los dos primeros trabajos (la y lb, se evaluó la interacción entre cepas seleccionadas de Rhizobium (apropiadas para la leguminosa forrajera tropical Centrosema macrocarpum y especies (Entrophospora colombiana, Acaulospora longula, Glomus manihotis de micorriza vesiculo arbuscular (MVA, en un suelo esterilizado, fijador de P. Los experimentos se diferenciaron por las fuentes de P utilizadas. Por su mayor producción de materia seca, absorción de minerales, nodulación y infección por MVA, se destacaron las plantas inoculadas con cuales quiera de las cepas de FIlizobiumy Glomus manihotis (Experimento la o Acaulospora longula (Experimento lb. En la tercera investigación (Experimento II, se evalúo en Centrosema la interacción MVA, Rhizobiumo N-químico (niveles equivalentes a 0, 30,55, 105,0 + Rhiz. y 30 + Rhiz. kg N ha-1 y dosis de P (0, 20, 40 y 80 kg ha-1. Es aconsejable aplicar pequeñas dosis (30 kg ha-1 de N al momento de la siembra e inocular con Rhizobium. Plantas inoculadas con MVA presentaron su óptimo crecimiento con 40 kg P ha-1. Dosis de 80 kg P ha-1 favoreció la eficiencia de la bacteria más no la del hongo.In the first two works (la and lb we evaluated the interation between selected stumps of Rhizobium (appropiate for the tropical forage legumes Centrosema macrocarpum and species (Entrophospora colombiana, Acaulospora longula, Glomus manihotis of vesicular-arbuscular mycorrhiza (MVA, in a sterelize soil fixer of P. The two experiments are different because we used different P sources. For the best production of dry matter, absorption of minerals, nodulation and infection for MVA; rebounded the plants with the inoculation with any of the Rhizobium´s stumps and Glomus manihotis (Experiment la of Acaulospora longula (Experiment lb. In the third investigation (Experiment II we evaluated in Centrosema the interaction MVA. Rhizobium and chemical N (levels equivalent to 0,30. 55, 105, O + Rhizobium and 30 + Rhizobium kg N ha-1 and amount of P (O, 20, 40 and 80 kg ha-1. Is advisable to apply small amount (30 kg ha-1 of N fertilizer at the time of sowing the Centrosema and the inoculation with Rhizobium. The plants inoculated with MVA showed a best growing in the amount 40kg Pha -1 80 kg Pha -1 helped in the efficacy of the bacterium and it didn't help in the efficacy of the fungus.

Satizabal E. Jorge H.

1987-03-01

 
 
 
 
161

Rhizobium strains competitiveness on bean nodulation in Cerrado soils Capacidade competitiva de estirpes de Rhizobium na nodulação do feijoeiro em solos de Cerrado  

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Full Text Available The objective of this work was to identify the most competitive and effective Rhizobium strains in order to increase common bean yield by nitrogen fixation as alternative or complementation to the nitrogen fertilization. Competitiveness tests were lead in axenic conditions, in Cerrado soil pots and in three field experiments, with native Rhizobium strains that were previously identified, according to their effectiveness and genetic variability. The identification of strains in nodules was performed using serological tests (axenic conditions - agglutination and enzyme linked immunosorbent (Elisa assays - and random amplified polymorfic DNA (RAPD (Cerrado soil. Plant yield was determined using the dry weight (greenhouse conditions, total N and grain yield (field experiments. Among the analyzed Rhizobium strains, native strain SLA 2.2 and commercial strain CIAT 899 were the dominant nodules in plants of the most productive plots, presenting yield productivity similar or higher to those obtained in treatments where 20 kg ha-1 of N were applied.O objetivo deste trabalho foi identificar as estirpes de Rhizobium mais efetivas e competitivas, a fim de maximizar a produtividade do feijoeiro por meio da fixação de nitrogênio, como alternativa à adubação nitrogenada. Foram conduzidos testes de competitividade em condições axênicas, em vasos com solo do Cerrado e em três experimentos de campo, com estirpes de Rhizobium nativas, previamente selecionadas quanto à efetividade e à variabilidade genética. A identificação das estirpes nos nódulos foi efetuada por meio das técnicas de aglutinação e ensaio imunoabsorvente de ligação de enzimas (Elisa, em condições de casa de vegetação, e pela técnica de DNA polimórfico amplificado ao acaso (RAPD, em solo de Cerrado. A produtividade das plantas foi determinada pela produção de matéria seca, teor de N e produção de grãos (condições de campo. A estirpe nativa SLA 2.2 e a estirpe comercial CIAT 899 foram dominantes nos nódulos das plantas das parcelas mais produtivas, com índices de produtividade iguais ou superiores aos obtidos nos tratamentos em que foram aplicados 20 kg ha-1 de N.

Ruy Raposeiras

2006-03-01

162

Cultivar and Rhizobium Strain Effects on the Symbiotic Performance of Pea (Pisum sativum)  

DEFF Research Database (Denmark)

The symbiotic performance of four pea (Pisum sativum L.) cultivars in combination with each of four strains of Rhizobium leguminosarum was studied in growth chamber experiments in order to estimate the effects of cultivars, strains and cultivar Ã? strain interaction on the variation in dry weight, N content and dry weight/N ratio. At harvest 63 days after planting, cultivars accounted for 75% of the variation in dry weight, while the Rhizobium strains accounted for 63% of the variation in N-content and 70% of the variation in dry weight/N ratio. Cultivar Ã? strain interactions were statistically significant, but of minor quantitative importance, accounting for 5â??15% of the total variation. Rhizobium strains also influenced the partitioning of N between reproductive and vegetative plant parts and between root and shoot biomass.

Skøt, Leif

1983-01-01

163

Yield response of fidders (berseem, shaftal, and lucerne) to rhizobium inclulation  

International Nuclear Information System (INIS)

Investigations were carried out to know the effect of Rhizobium inoculation on the fodder yield and nitrogen fixation of berseem, shaftal and lucerne in y clay loam soil in a pot culture experiment. A basal dressing of nitrogen, phosphorus (P/sub 2/O/sub 5/) and Potash (K/sub 2/O) at 20,80,40 Kg/ha as urea, single superphosphate and potassium sulphate were applied to each pot. The results revealed that Rhizobium inoculation significantly increased the green fodder yield in four cuttings of berseem by 35 to 147 percent of shaftal by 41 to 60 percent and of lucerne by 41 to 74 percent. Shoos N-yield in four cuttings exhibited a significant increasing trend by 21 to 158 percent in berseem, 40 to 69 percent in shaftal and 41 to 78 percent in lucerne due to biological nitrogen fixation as a result of Rhizobium inoculation. (author)

1997-01-01

164

Herbivores alter the fitness benefits of a plant-rhizobium mutualism  

Science.gov (United States)

Mutualisms are best understood from a community perspective, since third-party species have the potential to shift the costs and benefits in interspecific interactions. We manipulated plant genotypes, the presence of rhizobium mutualists, and the presence of a generalist herbivore and assessed the performance of all players in order to test whether antagonists might alter the fitness benefits of plant-rhizobium mutualism, and vice versa how mutualists might alter the fitness consequences of plant-herbivore antagonism. We found that plants in our experiment formed more associations with rhizobia (root nodules) in the presence of herbivores, thereby increasing the fitness benefits of mutualism for rhizobia. In contrast, the effects of rhizobia on herbivores were weak. Our data support a community-dependent view of these ecological interactions, and suggest that consideration of the aboveground herbivore community can inform ecological and evolutionary studies of legume-rhizobium interactions.

Heath, Katy D.; Lau, Jennifer A.

2011-03-01

165

SYNERGISTIC INTERACTION BETWEEN ARBUSCULAR MYCORRHIZAL FUNGI, RHIZOBIUM AND PHOSPHATE SOLUBILISING BACTERIA ON VIGNA UNGUICULATA (L VERDC.  

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Full Text Available Green house pot experiments were conducted to evaluate the effect of Arbuscular Mycorrhizal(AM Fungi (Funneliformis mosseae along with the dual inoculation of AM fungi (Funneliformis mosseae with Rhizobium, Phosphate solubilising bacteria (PSB and a triple inoculation of AM Fungi (Funneliformis mosseae, Rhizobium, and PSB in Vigna unguiculata (L Verdc. Growth parameters such as plant height, dry weight of root and shoot, spore number, per cent root colonization, number of nodules was recorded and P and N uptake were estimated at the intervals of 15, 30 and 45 days. Results revealed that inoculation of AM Fungi (Funneliformis mosseae + Rhizobium+ PSB showed an increase in all the growth parameters when compared with dual inoculation. The combined inoculation of bacteria and AM fungi evidence provide that these two organisms are synergistically involved in the beneficial effects of Vigna unguiculata (L Verdc.

Romana M Mirdhe* and HC Lakshman

2014-05-01

166

The isolation, enumeration, and characterization of Rhizobium bacteria of the soil in Wamena Biological Garden  

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Full Text Available The eleven soil samples have been isolated and characterized. The aims of the study were to get the pure culture and some data which described about enumeration and especially their characters in relation to the acids and bases reaction in their growth. The isolation of the bacteria use Yeast Extract Mannitol Agar medium (YEMA while the characterization by using YEMA medium mixed with Brom Thymol Blue and Congo Red indicators respectively. The results showed that eighteen isolates have been isolated which consisted of three low growing and fifteen fast growing bacteria. Two isolates were not indicated Rhizobium and sixteen were Rhizobium. Density of Rhizobium enumeration was varied which related to soil organic matter content. The enumeration bacteria in YEMA medium were in the range of 0.6 x 105 and 11.6 x 105 CFU /g soil. The highest population was found in soil sample of Wieb vegetation.

SRI PURWANINGSIH

2005-04-01

167

[Bioprotection mechanisms of the lentil plant by Rhizobium leguminosarum against Fusarium oxysporum f. sp. lentis].  

Science.gov (United States)

Living and heat-killed bacterial cells of Rhizobium leguminosarum protected totally lentil plants against infection by the pathogen Fusarium oxysporum MR 84. Culture filtrate of this rhizobacterium was also able to protect the plants to a high degree. However, when they were inoculated separately of the pathogen, living bacterial cells did not protect the plants whereas culture filtrate and killed bacterial cells protected them. These results suggest that Rhizobium cannot protect lentil plants without interaction with the pathogen, but the culture filtrate and the killed bacterial cells can protect them even in the absence of this interaction. It seems that the culture filtrate and the killed bacterial cells contain signals able to induce plant resistance. Those signals would be suppressed once Rhizobium is in contact with the plant. PMID:14746271

Essalmani, Haiat; Lahlou, Houria

2003-12-01

168

Rhizobium azibense sp. nov., a nitrogen fixing bacterium isolated from root-nodules of Phaseolus vulgaris.  

Science.gov (United States)

Three microbial strains isolated from common beans, 23C2T (Tunisia), Gr42 (Spain) and IE4868 (Mexico), which have been identified previously as representing a genomic group closely related to Rhizobium gallicum, are further studied here. Their 16S rRNA genes showed 98.5-99% similarity with Rhizobium loessense CCBAU 7190BT, R. gallicum R602spT, Rhizobium mongolense USDA 1844T and Rhizobium yanglingense CCBAU 71623T. Phylogenetic analysis based on recA, atpD, dnaK and thrC sequences showed that the novel strains were closely related and could be distinguished from the four type strains of the closely related species. Strains 23C2T, Gr42 and IE4868 could be also differentiated from their closest phylogenetic neighbours by their phenotypic and physiological properties and their fatty acid contents. All three strains harboured symbiotic genes specific to biovar gallicum. Levels of DNA-DNA relatedness between strain 23C2T and the type strains of R. loessense, R. mongolense, R. gallicum and R. yanglingense ranged from 58.1 to 61.5%. The DNA G+C content of the genomic DNA of strain 23C2T was 59.52%. On the basis of these data, strains 23C2T, Gr42 and IE4868 were considered to represent a novel species of the genus Rhizobium for which the name Rhizobium azibense is proposed. Strain 23C2T (=CCBAU 101087T=HAMBI3541T) was designated as the type strain. PMID:24478208

Mnasri, Bacem; Liu, Tian Yan; Saidi, Sabrine; Chen, Wen Feng; Chen, Wen Xin; Zhang, Xiao Xia; Mhamdi, Ridha

2014-05-01

169

A Rhizobium selenitireducens protein showing selenite reductase activity.  

Science.gov (United States)

Biobarriers remove, via precipitation, the metalloid selenite (SeO??²) from groundwater; a process that involves the biological reduction of soluble SeO??² to insoluble elemental red selenium (Se?). The enzymes associated with this reduction process are poorly understood. In Rhizobium selenitireducens at least two enzymes are potentially involved; one, a nitrite reductase reduces SeO??² to Se? but another protein may also be involved which is investigated in this study. Proteins from R. selenitireducens cells were precipitated with ammonium sulfate and run on native electrophoresis gels. When these gels were incubated with NADH and SeO??² a band of precipitated Se? developed signifying the presence of a SeO??² reducing protein. Bands were cut from the gel and analyzed for peptides via LCMSMS. The amino acid sequences associated with the bands indicated the presence of an NADH:flavin oxidoreductase that resembles YP_001326930 from Sinorhizobium medicae. The protein is part of a protein family termed old-yellow-enzymes (OYE) that contain a flavin binding domain. OYE enzymes are often involved in protecting cells from oxidative stress and, due in part to an active site that has a highly accessible binding pocket, are generally active on a wide range of substrates. This report is the first of an OYE enzyme being involved in SeO??² reduction. PMID:24474405

Hunter, W J

2014-03-01

170

Studies on mutation and repair in Rhizobium japonicum  

International Nuclear Information System (INIS)

In the presence of NTG, Rhizobium japonicum loses viability very rapidly. 50% survival is achieved within 4 mins using 50 ?gm/ml. When a constant time of 30 min is maintained then a concentration of 18 ?gm/ml gives 50% survival. The low doses of NTG did not yield any auxotrophs. The antibiotics like penicillion, ampicillin and streptopenicillin were used as agents for enrichment of mutants, ampicillin was quite effective. A fairly efficient mechanism for repair from U.V. damage appears to exist. A greater part of this repair is due to the prevalence of dark repair mechanism. Mutants with increased sensitivity to U.V. repair failed to transform normally suggesting that the two processes of U.V. repair and genetic recombination may be related. The levels of deoxyribonucleases increased at the competent state. The activity at pH 7.5 and 8.4 but not at 5.5 was greater towards irradiated DNA, a prerequisite for any enzyme involved in U.V. repair. (author)

1975-12-06

171

Biologic fixation of nitrogen in irradiated rhizobium strips  

International Nuclear Information System (INIS)

Native Rhizobium sp. and Bradyrhizobium sp. isolates from the root nodules of bean and cowpea were selected. Six isolates, and the SEMIA 4077 (R. leguminosarum bv. phaseolus) and SEMIA 6145 (Bradyrhizobium sp) strains used as references, were irradiated with ultraviolet light (R-uv) and gamma rays (R-?). The D37 values for the rhizobial strain SEMIA 4077 were 43 J.m-2 (UV) and 32 Gy (R-?) and for the SEMIA 6145 were 45 J.m-2 (UV) and 35 Gy (R-gamma). Through a greenhouse experiment the irradiated isolates were inoculated on bean (P. vulgaris L., cv. Princesa) and on cowpea [Vigna unguiculata, (L.) Walp, cv. IPA-206] seedlings, in an attempt to evaluate the sensitivity of the host plants, and possible effects on their nodulation. Differences in responses to nodulation due to the effect of irradiation were observed for the isolates tested. Significantly differences were observed only for nodules dry matter yield of the IPA-206 cultivar. Gamma irradiated treatment were statistically superior to treatments with ultraviolet light in relation. (author)

2002-08-11

172

Influence of carbofuran on certain metabolic and symbiotic activities of a cowpea Rhizobium  

International Nuclear Information System (INIS)

Using carbon 14 radioisotope an in-vitro study of the effect of insecticides, carbofuran, on the metabolic and symbiotic activities of Rhizobium sp. cowpea group, was carried out. The study indicated that at 10 ppm carbofuran inhibited the in-vitro growth of the bacterium, suppressed the oxidation of all the Trichloroacetic acid (TCA) cycle intermediates, significantly reduced glucose oxidation and translocation and affected the growth and symbiotic activities of the cowpea as reflected by a reduction in the dry matter production and total nitrogen content. The insecticide was itself degraded by the Rhizobium sp. within 30 days of incubation

1983-03-01

173

Low temperature impact on protein content and peroxidase activity during pea inoculation with Rhizobium leguminosarum  

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Full Text Available The study was focused on changes in protein content and peroxidase activity in pea roots subjected to infection with Rhizobium leguminosarum and to low temperature. The amount of protein and peroxidase activity were shown to change in the course of interaction with nodular bacteria and to depend on the temperature and root zones susceptibility to rhizobia. It was concluded that changes in the content of soluble protein and peroxidase activity witness adaptation changes in pea seedlings, hich facilitate normal course of metabolic processes and ensure regulation of plant interaction with Rhizobium in hypothermal conditions.

Akimova G.P.

2010-11-01

174

Danish Rhizobium leguminosarum strains nodulating â??Afghanistanâ?? pea (Pisum sativum)  

DEFF Research Database (Denmark)

A wild pea (Pisum sativum L.) native to Afghanistan normally known to be resisant to nodulation with European strains of Rhizobium leguminosarum was nodulated early and effectively in field soil in Denmark. Isolates from nodules formed effective nodules abundantly on 'Afghanistan' on reinfection under aseptic conditions. Five types differing in isoenzyme composition pattern were found among 15 isolates from 'Afghanistan' nodules. None were identical with 'Tom' strain from Turkey, which also forms effective nodules with 'Afghanistan'. The five types were also different with respect to isoenzyme pattern with Rhizobium leguminosarum strains isolated from a modern pea variety cultivated in the same field.

Jensen, Erik Steen; Sørensen, Lasse Holst

1986-01-01

175

Characterization of NopP, a Type III Secreted Effector of Rhizobium sp. Strain NGR234  

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The type three secretion system (TTSS) encoded by pNGR234a, the symbiotic plasmid of Rhizobium sp. strain NGR234, is responsible for the flavonoid- and NodD1-dependent secretion of nodulation outer proteins (Nops). Abolition of secretion of all or specific Nops significantly alters the nodulation ability of NGR234 on many of its hosts. In the closely related strain Rhizobium fredii USDA257, inactivation of the TTSS modifies the host range of the mutant so that it includes the improved Glycine...

Ausmees, Nora; Kobayashi, Hajime; Deakin, William J.; Marie, Corinne; Krishnan, Hari B.; Broughton, William J.; Perret, Xavier

2004-01-01

176

Genetic characterization and nitrogen fixation capacity of Rhizobium strains on common bean Caracterização genética e capacidade de fixação de nitrogênio de estirpes de Rhizobium em feijoeiro  

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Full Text Available This study aimed to genetically characterize four new Rhizobium strains, and to evaluate their nodulation and fixation capacity compared to commercial strains and to native rhizobia population of a Brazilian Rhodic Hapludox. Two experiments were carried out in randomized blocks design, under greenhouse conditions, in 2007. In the first experiment, the nodulation and nitrogen fixation capacity of new strains were evaluated, in comparison to the commercial strains CIAT-899 and PRF-81 and to native soil population. It was carried out in plastic tubes filled with vermiculite. DNA extractions and PCR sequencing of the intergenic space were made from the isolated pure colonies, in order to genetically characterize the strains and the native rhizobia population. In the second experiment, the nodulation and productivity of common beans Perola cultivar were determined, with the use of evaluated strains, alone or in mixture with PRF-81 strain. It was carried out in pots filled with soil. The native soil population was identified as Rhizobium sp. and was inefficient in nitrogen fixation. Three different Rhizobium species were found among the four new strains. The LBMP-4BR and LBMP-12BR new strains are among the ones with greatest nodulation and fixation capacity and exhibit differential responses when mixed to PRF-81.O objetivo deste trabalho foi a caracterização genética de quatro novas estirpes de Rhizobium e a avaliação de sua capacidade de fixação de N2 e nodulação, comparadas a estirpes comerciais e à população nativa de rizóbios de um Latossolo Vermelho. Dois experimentos foram conduzidos em blocos ao acaso, em casa de vegetação. No primeiro experimento, conduzido em tubetes com vermiculita, avaliaram-se a nodulação e a capacidade de fixação das novas estirpes, em comparação com as estirpes comerciais CIAT-899 e PRF-81 e com a população nativa do solo. Das colônias puras isoladas, extraiu-se o DNA genômico e realizou-se o seqüenciamento do espaço intergênico, para a caracterização genética das estirpes e da população nativa de rizóbios. O segundo experimento foi realizado em vasos com solo, para determinação da produtividade e da nodulação do feijoeiro, cultivar Pérola, com o uso das estirpes isoladamente ou em mistura com a PRF-81. A população nativa do solo foi identificada como Rhizobium sp. e se mostrou ineficiente na fixação de nitrogênio. Foram encontradas três espécies de Rhizobium entre as quatro novas estirpes. As estirpes LBMP-4BR e LBMP-12BR estão entre as que têm maior capacidade de nodulação e fixação de N2, e apresentam respostas diferenciadas quando misturadas à PRF-81.

Tehuni Orlando González

2008-09-01

177

Genetic characterization and nitrogen fixation capacity of Rhizobium strains on common bean / Caracterização genética e capacidade de fixação de nitrogênio de estirpes de Rhizobium em feijoeiro  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O objetivo deste trabalho foi a caracterização genética de quatro novas estirpes de Rhizobium e a avaliação de sua capacidade de fixação de N2 e nodulação, comparadas a estirpes comerciais e à população nativa de rizóbios de um Latossolo Vermelho. Dois experimentos foram conduzidos em blocos ao acas [...] o, em casa de vegetação. No primeiro experimento, conduzido em tubetes com vermiculita, avaliaram-se a nodulação e a capacidade de fixação das novas estirpes, em comparação com as estirpes comerciais CIAT-899 e PRF-81 e com a população nativa do solo. Das colônias puras isoladas, extraiu-se o DNA genômico e realizou-se o seqüenciamento do espaço intergênico, para a caracterização genética das estirpes e da população nativa de rizóbios. O segundo experimento foi realizado em vasos com solo, para determinação da produtividade e da nodulação do feijoeiro, cultivar Pérola, com o uso das estirpes isoladamente ou em mistura com a PRF-81. A população nativa do solo foi identificada como Rhizobium sp. e se mostrou ineficiente na fixação de nitrogênio. Foram encontradas três espécies de Rhizobium entre as quatro novas estirpes. As estirpes LBMP-4BR e LBMP-12BR estão entre as que têm maior capacidade de nodulação e fixação de N2, e apresentam respostas diferenciadas quando misturadas à PRF-81. Abstract in english This study aimed to genetically characterize four new Rhizobium strains, and to evaluate their nodulation and fixation capacity compared to commercial strains and to native rhizobia population of a Brazilian Rhodic Hapludox. Two experiments were carried out in randomized blocks design, under greenho [...] use conditions, in 2007. In the first experiment, the nodulation and nitrogen fixation capacity of new strains were evaluated, in comparison to the commercial strains CIAT-899 and PRF-81 and to native soil population. It was carried out in plastic tubes filled with vermiculite. DNA extractions and PCR sequencing of the intergenic space were made from the isolated pure colonies, in order to genetically characterize the strains and the native rhizobia population. In the second experiment, the nodulation and productivity of common beans Perola cultivar were determined, with the use of evaluated strains, alone or in mixture with PRF-81 strain. It was carried out in pots filled with soil. The native soil population was identified as Rhizobium sp. and was inefficient in nitrogen fixation. Three different Rhizobium species were found among the four new strains. The LBMP-4BR and LBMP-12BR new strains are among the ones with greatest nodulation and fixation capacity and exhibit differential responses when mixed to PRF-81.

Tehuni Orlando, González; João Carlos, Campanharo; Eliana Gertrudes de Macedo, Lemos.

178

Mythe et pouvoir  

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Full Text Available Si le mythe évoque en nous un monde idéal, le pouvoir nous rappel l’existence d’un monde bien réel. La tension ainsi créée est du même ordre que celle liée à la pensée sauvage et la pensée rationnelle. Le pouvoir, dans toutes ses manifestations et ses degrés dont le politique, a été toujours exploré par une pensée organisée, rationnellement construite, et ce type de pensée a été pendant trois siècles la structure des destins de nos sociétés. Les rêves collectifs bien que tenus en compte, n’entraient nullement dans les analyses finales d’une société et de son devenir. En effet tout ce qui tient de “l’irrationnel” restait à côté et aujourd’hui encore sont comptés ceux qui osent s’introduir dans une telle démarche. A la lecture de ces contributions, plusieurs questions surgissent. Il convient de se demander sous quelles configurations se composent les relations entre les deux termes mythe et pouvoir aujourd’hui. Quels sont les mythes du pouvoir à partir desquels se produit l’obéissance ? Mais aussi sous quelles formes a lieu l’invention des mythes qu’ attaquent ce qui est établit, ce qui est tolérable? Et plus encore, sous quel type de déplacement de sens, de chevauchement, se tisse la trame entre les mythes et les pouvoirs soutenant les images du monde qui gouvernent nos existences? De même pour la littérature et l’art en général, il faut questionner ce lien ténu par les artistes et les écrivains avec la société qui les porte , lien parfois dénié ou conflictuel.

Alejandro Ruidrejo

2013-07-01

179

Effect of Rhizobium Inoculation on Seedling Growth of Albizia niopides (Spruce Ex Bnth Burkart  

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Full Text Available Investigation was carried out on the effect of Rhizobium inoculation on the Seedling Growth and development of Albizia niopoides in a glass house at the International Institute of Tropical Agriculture (IITA Ibadan Nigeria. This involved isolation of Rhizobium from this species microbiologically. There were four treatments in all namely 1 mL Rhizobium inoculation; 5 mL Rhizobium inoculation; 10 mL Rhizobium inoculation and control (without Rhizobium inoculation. They were arranged in a randomized complete block design and replicated three times. The parameters considered went height, collar diameter, leaf number and leaf area. Significant differences were recorded among the treatments with respect to plant height. 10 mL Rhizobium inoculation gave maximum height of 93.6 cm; Diameter increment of 0.77 mm (14 WAP, leaf number 14.7 and leaf area 193.4. The inoculated treatments produced nodule number ranging between 336.7 and 496.0 while uninoculated treatment gave 247.6 nodules dry matter production was directly proportional to the quantity of Rhizobium inoculation applied. 10 mL Rhizobium broth produced the highest nodule dry matter of 24.7 g which was significantly different from the control (13.97 g. No significant difference was recorded among the treatment vis-a-vis leaf and root dry matter production by seedlings of A. niopoides. it is recommended that Rhizobia inoculation should be adopted for the establishment of some nitrogen fixing tree where native Rhizobia is not available.

2007-01-01

180

GAT 3 - fuel cells and their management (PACoGES). Progress report; GAT 3 - piles a combustible et leur gestion (PACoGES). Rapport final (juillet 2002 a juin 2004)  

Energy Technology Data Exchange (ETDEWEB)

The Topic Analysis Group PACoGES ('Piles a Combustible et leur Gestion') has conducted thoughts on fuel cells and their management with all the searchers concern with researches and developments on fuel cells and in particular on solid oxide fuel cells (SOFC, ITSOFC) running at high temperature (600 to 1000 C). This has concerned about 200 searchers working in about fifty laboratories (CNRS, CEA, EDF, GDF, INRETS, CNAM, Armines, and several industrial teams). Here is given the final report 2002-2004 concerning all the researches carried out by this Group. (O.M.)

Lamy, C.

2005-07-01

 
 
 
 
181

Tellurium and Selenium Resistance in Rhizobia and Its Potential Use for Direct Isolation of Rhizobium meliloti from Soil †  

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Forty-eight Rhizobium and Bradyrhizobium strains were screened for resistance to tellurite, selenite, and selenate. High levels of resistance to the metals were observed only in Rhizobium meliloti and Rhizobium fredii strains; the MICs were 2 to 8 mM for Te(IV), >200 mM for Se(VI), and 50 to 100 mM for Se(IV). Incorporation of Se and Te into growth media permitted us to directly isolate R. meliloti strains from soil. Mutant strains of rhizobia having decreased levels of Se and Te resistance w...

Kinkle, B. K.; Sadowsky, M. J.; Johnstone, K.; Koskinen, W. C.

1994-01-01

182

Nitrogen fixation ability of exopolysaccharide synthesis mutants of Rhizobium sp. strain NGR234 and Rhizobium trifolii is restored by the addition of homologous exopolysaccharides.  

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Several transposon Tn5-induced mutants of the broad-host-range Rhizobium sp. strain NGR234 produce little or no detectable acidic exopolysaccharide (EPS) and are unable to induce nitrogen-fixing nodules on Leucaena leucocephala var. Peru or siratro plants. The ability of these Exo- mutants to induce functioning nodules on Leucaena plants was restored by coinoculation with a Sym plasmid-cured (Nod- Exo+) derivative of parent strain NGR234, purified EPS from the parent strain, or the oligosacch...

Djordjevic, S. P.; Chen, H.; Batley, M.; Redmond, J. W.; Rolfe, B. G.

1987-01-01

183

Inoculant Production with Diluted Liquid Cultures of Rhizobium spp. and Autoclaved Peat: Evaluation of Diluents, Rhizobium spp., Peats, Sterility Requirements, Storage, and Plant Effectiveness  

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Fully grown broth cultures of various fast- and slow-growing rhizobia were deliberately diluted with various diluents before their aseptic incorporation into autoclaved peat in polypropylene bags (aseptic method) or mixed with the peat autoclaved in trays (tray method). In a factorial experiment with the aseptic method, autoclaved and irradiated peat samples from five countries were used to prepare inoculants with water-diluted cultures of three Rhizobium spp. When distilled water was used as...

1985-01-01

184

Symbiotic effectiveness and ecological characterization of indigenous Rhizobium loti populations in Uruguay Eficiência simbiótica e caracterização ecológica de uma população nativa de Rhizobium loti no Uruguai  

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The objectives of this work were to describe the distribution, density and seasonal variation of the indigenous populations of Rhizobium loti in different Uruguayan soils and to determine the symbiotic effectiveness and stress tolerance factors of different isolates, both with the aim of obtaining selected strains to re-introduce as inoculants in Lotus pastures. R. loti was present in ten soils studied and their densities varied from year to year and within each soil. All the isolates nodulat...

1999-01-01

185

Isolation and Selection of Rhizobium Tolerant to Pesticides and Aluminum from Acid Soils in Indonesia  

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Full Text Available Application of Rhizobium as inoculum in acid soil requires specific characters, namely high tolerance to pesticide residues, soil acidity, and high concentration of Aluminum. This study was conducted to isolate Rhizobium having these characters. Inspite of acid soils from Kalimantan, Sumatra, Sulawesi and Java; root nodules of legumes planted in those regions were used as source of isolates. Rhizobial isolation was done using direct isolation and enrichment technique. A paper disc diffusion technique was used in selecting tolerance to pesticides. The selected isolates were examined the tolerance to pH, Al, and ability to form root nodule with soybean. From soil analysis, it could be seen the correlation between pH value and Al concentration. It means that the lower pH value the higher Al concentration. The number of Rhizobium isolates and its tolerance to paraquat was depended on soil type. From 173 strains of isolated Rhizobium, 24 strains were tolerance to pesticides and Aluminum. They were able to grow in wide range of pH, namely 3 – 8, or some of them in 5 - 8. Around 92% of the selected bacteria could form root nodules with soybean plant in different number and size. Hopefully, these isolates can be applied in the pesticide polluted agricultural lands, especially in acid soils with high concentration of Al, and it can also increase soybean production.

Agus Supriyo

2011-01-01

186

Populasi Bakteri Rhizobium di Tanah pada beberapa Tanaman dari Pulau Buton, Kabupaten Muna, Propinsi Sulawesi Tenggara  

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Full Text Available The research was conducted in order to know population of Rhizobium bacteria in the soil at several plant from Buton island, Muna regency, Southeast Sulawesi. The purpose of the study was to get the population data and pure cultures of Rhizobium bacteria. Rhizobium bacteria were isolated from 13 sample from rhizosphere of fruit plant, 14 sample soil from rhizosphere of yield plant, 5 sample soil from rhizosphere of horticulture plant, and 8 samples soil was from forest plant. Isolation was conducted in standard medium of Yeast Extract Mannitol Agar (YEMA, the inoculation at (27-280C, and the population was counted by plate count methods. The growth characteristic of strain was observed by using YEMA medium mixed respectively with Brom Thymol Blue and Congo Red as an indicators. The population of Rhizobium bacteria was in the range of 7-115 × 105 CFU g-1 soil, and the highest population was found from the sample soil from rhizosphere with Ipomea batatas plant. Forty nine gave of pure culture, thirty five isolates can be grouped as fast growing, while fourteen can be grouped as slow growing.

Sri Purwaningsih

2009-01-01

187

Nodulation of Sesbania species by Rhizobium (Agrobacterium) strain IRBG74 and other rhizobia.  

Science.gov (United States)

Concatenated sequence analysis with 16S rRNA, rpoB and fusA genes identified a bacterial strain (IRBG74) isolated from root nodules of the aquatic legume Sesbania cannabina as a close relative of the plant pathogen Rhizobium radiobacter (syn. Agrobacterium tumefaciens). However, DNA:DNA hybridization with R. radiobacter, R. rubi, R. vitis and R. huautlense gave only 44%, 5%, 8% and 8% similarity respectively, suggesting that IRBG74 is potentially a new species. Additionally, it contained no vir genes and lacked tumour-forming ability, but harboured a sym-plasmid containing nifH and nodA genes similar to those in other Sesbania symbionts. Indeed, IRBG74 effectively nodulated S. cannabina and seven other Sesbania spp. that nodulate with Ensifer (Sinorhizobium)/Rhizobium strains with similar nodA genes to IRBG74, but not species that nodulate with Azorhizobium or Mesorhizobium. Light and electron microscopy revealed that IRBG74 infected Sesbania spp. via lateral root junctions under flooded conditions, but via root hairs under non-flooded conditions. Thus, IRBG74 is the first confirmed legume-nodulating symbiont from the Rhizobium (Agrobacterium) clade. Cross-inoculation studies with various Sesbania symbionts showed that S. cannabina could form fully effective symbioses with strains in the genera Rhizobium and Ensifer, only ineffective ones with Azorhizobium strains, and either partially effective (Mesorhizobium huakii) or ineffective (Mesorhizobium plurifarium) symbioses with Mesorhizobium. These data are discussed in terms of the molecular phylogeny of Sesbania and its symbionts. PMID:19555380

Cummings, Stephen P; Gyaneshwar, Prasad; Vinuesa, Pablo; Farruggia, Frank T; Andrews, Mitchell; Humphry, David; Elliott, Geoffrey N; Nelson, Andrew; Orr, Caroline; Pettitt, Deborah; Shah, Gopit R; Santos, Scott R; Krishnan, Hari B; Odee, David; Moreira, Fatima M S; Sprent, Janet I; Young, J Peter W; James, Euan K

2009-10-01

188

Free-Living Rhizobium Strain Able To Grow on N2 as the Sole Nitrogen Source  

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A Rhizobium strain isolated from stem nodules of the legume Sesbania rostrata was shown to grow on atmospheric nitrogen (N2) as the sole nitrogen source. Non-N2-fixing mutants isolated directly on agar plates formed nodules that did not fix N2 when inoculated into the host plant.

Dreyfus, B. L.; Elmerich, C.; Dommergues, Y. R.

1983-01-01

189

Mass spectrometric analysis of chitin oligosaccharides produced by Rhizobium NodC protein in Escherichia coli.  

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A system for studying the in vivo activity of Rhizobium NodC protein in Escherichia coli has been developed. Using thin-layer chromatography, high-performance liquid chromatography, and mass spectrometry, we show that in this system R. leguminosarum bv. viciae NodC protein directs the synthesis of chitinpentaose, chitintetraose, chitintriose, and two as yet unidentified modified chitin oligosaccharides.

Kamst, E.; Drift, K. M.; Thomas-oates, J. E.; Lugtenberg, B. J.; Spaink, H. P.

1995-01-01

190

Purification and electron microscopy of a large plasmid of Rhizobium meliloti 41.  

Science.gov (United States)

A large plasmid DNA molecule was purified from Rhizobium meliloti 41 by CsCl-ethidium bromide density gradient centrifugation. Electron microscopic and agarose gel electrophoretic data suggest that addition of alkali effectively removes the chromosomal DNA, the plasmid DNA can be precipitated from the cleared lysate and no gradient centrifugation is needed for plasmid purification. PMID:6659858

Mink, M; Sik, T

1983-01-01

191

Rhizobium freirei sp. nov., a symbiont of Phaseolus vulgaris that is very effective at fixing nitrogen.  

Science.gov (United States)

Common bean (Phaseolus vulgaris L.) can establish symbiotic associations with several Rhizobium species; however, the effectiveness of most strains at fixing nitrogen under field conditions is very low. PRF 81(T) is a very effective strain, usually referred to as Rhizobium tropici and used successfully in thousands of doses of commercial inoculants for the common bean crop in Brazil; it has shown high rates of nitrogen fixation in all areas representative of the crop in the country. Here, we present results that indicate that PRF 81(T), although it belongs to the 'R. tropici group', which includes 10 Rhizobium species, R. tropici, R. leucaenae, R. lusitanum, R. multihospitium, R. miluonense, R. hainanense, R. calliandrae, R. mayense, R. jaguaris and R. rhizogenes, represents a novel species. Several morpho-physiological traits differentiated PRF 81(T) from related species. Differences were also confirmed in the analysis of rep-PCR (sharing less than 45?% similarity with the other species), MLSA with recA, atpD and rpoB genes, and DNA-DNA hybridization. The novel species, for which we propose the name Rhizobium freirei sp. nov., is able to establish effective root nodule symbioses with Phaseolus vulgaris, Leucaena leucocephala, Leucaena esculenta, Crotalaria juncea and Macroptilium atropurpureum. The type strain is PRF 81(T) (?=?CNPSo 122(T)?=?SEMIA 4080(T)?=?IPR-Pv81(T)?=?WDCM 440(T)). PMID:23771622

Dall'Agnol, Rebeca Fuzinatto; Ribeiro, Renan Augusto; Ormeño-Orrillo, Ernesto; Rogel, Marco Antonio; Delamuta, Jakeline Renata Marçon; Andrade, Diva Souza; Martínez-Romero, Esperanza; Hungria, Mariangela

2013-11-01

192

All nod genes of Rhizobium meliloti are involved in alfalfa nodulation by exo mutants.  

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Nodulation of alfalfa by exoB mutants of Rhizobium meliloti occurred without root hair curling or infection thread formation. nod exoB double mutants had the same nodulation deficiency as single nod mutants. Therefore, all the known nod genes are involved in nodule induction by exoB mutants, which apparently occurs via intercellular invasion.

Klein, S.; Walker, G. C.; Signer, E. R.

1988-01-01

193

ets 10  

ETS 10 Application for the Transfer of a Permit Version 3, 30 August 2008 The Greenhouse Gas Emissions Trading Scheme Regulations 2005 Confidentiality Statement The information submitted in respect of this application ...

194

ets 3  

ETS 3.2 Application for the Allocation of Allowances from the Phase II New Entrant Reserve Issue 2, 30 August 2008 The Greenhouse Gas Emissions Trading Scheme Regulations 2005 Confidentiality Statement The information ...

195

Effects of Rhizobium inoculation on Trifolium resupinatum antioxidant system under sulfur dioxide pollution  

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Full Text Available Introduction: Plant growth stimulating rhizobacteria are beneficial bacteria that can cause resistance to various stresses in plants. One of these stresses is SO2 air pollution. SO2 is known as a strong damaging air pollutant that limits growth of plants. The aim of this study is evaluation of the effects of bacterial inoculation with native and standard Rhizobium on Persian clover root growth and antioxidants activity and capacity under air SO2 pollution. Materials and methods: In this study, 31 days plants (no-inoculated and inoculated with two strains of Rhizobium exposed to the different concentrations of SO2 (0 as a control, 0.5, 1, 1.5 and 2 ppm for 5 consecutive days and 2 hours per day. Results: Results showed different concentrations of SO2 had a significant effect on Persian clover root weight and antioxidant system. Increasing SO2 stress decreased root fresh and dry weight and antioxidant capacities (IC50 and increased antioxidant activities (I% of Persian clover leaves significantly in comparison to the control plants (under 0 ppm and increased SOD, CAT and GPX activity. Inoculation of Persian clover plants with native and standard Rhizobium increased root weight and did not show a significant effect on antioxidants activity and capacity, but interaction between Rhizobium inoculation and SO2 treatment reduced significantly the stress effects of high concentration of SO2 on root growth and antioxidants activity and capacity. In fact, level of this change of root growth and antioxidant system under SO2 pollution stress in inoculated plants was lower than in the non-inoculated plants. Discussion and conclusion: As a result, an increase in SO2 concentration caused a decrease in root weight, increase in antioxidants activity and capacity of Persian clover. Inoculation with Rhizobium strains could alleviate the effect of SO2 pollution on antioxidant system by effects on root growth.

Ladan Bayat

2014-01-01

196

Rhizobium strains competitiveness on bean nodulation in Cerrado soils / Capacidade competitiva de estirpes de Rhizobium na nodulação do feijoeiro em solos de Cerrado  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O objetivo deste trabalho foi identificar as estirpes de Rhizobium mais efetivas e competitivas, a fim de maximizar a produtividade do feijoeiro por meio da fixação de nitrogênio, como alternativa à adubação nitrogenada. Foram conduzidos testes de competitividade em condições axênicas, em vasos com [...] solo do Cerrado e em três experimentos de campo, com estirpes de Rhizobium nativas, previamente selecionadas quanto à efetividade e à variabilidade genética. A identificação das estirpes nos nódulos foi efetuada por meio das técnicas de aglutinação e ensaio imunoabsorvente de ligação de enzimas (Elisa), em condições de casa de vegetação, e pela técnica de DNA polimórfico amplificado ao acaso (RAPD), em solo de Cerrado. A produtividade das plantas foi determinada pela produção de matéria seca, teor de N e produção de grãos (condições de campo). A estirpe nativa SLA 2.2 e a estirpe comercial CIAT 899 foram dominantes nos nódulos das plantas das parcelas mais produtivas, com índices de produtividade iguais ou superiores aos obtidos nos tratamentos em que foram aplicados 20 kg ha-1 de N. Abstract in english The objective of this work was to identify the most competitive and effective Rhizobium strains in order to increase common bean yield by nitrogen fixation as alternative or complementation to the nitrogen fertilization. Competitiveness tests were lead in axenic conditions, in Cerrado soil pots and [...] in three field experiments, with native Rhizobium strains that were previously identified, according to their effectiveness and genetic variability. The identification of strains in nodules was performed using serological tests (axenic conditions) - agglutination and enzyme linked immunosorbent (Elisa) assays - and random amplified polymorfic DNA (RAPD) (Cerrado soil). Plant yield was determined using the dry weight (greenhouse conditions), total N and grain yield (field experiments). Among the analyzed Rhizobium strains, native strain SLA 2.2 and commercial strain CIAT 899 were the dominant nodules in plants of the most productive plots, presenting yield productivity similar or higher to those obtained in treatments where 20 kg ha-1 of N were applied.

Raposeiras, Ruy; Marriel, Ivanildo Evódio; Muzzi, Maria Rita Scotti; Paiva, Edilson; Pereira Filho, Israel Alexandre; Carvalhais, Lilia Costa; Passos, Raul Vinícius Magalhães; Pinto, Patrícia Pereira; Sá, Nadja Maria Horta de.

197

Random amplified polymorphic DNA analysis of effective Rhizobium sp. associated with beans cultivated in brazilian cerrado soils Caracterização, via RAPD, de estirpes efetivas de Rhizobium sp associadas ao feijoeiro cultivado em solos de cerrado no Brasil  

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Efficient bean nodulating Rhizobium strains, isolated from different Brazilian cerrado soils, were characterized by RAPD. This study showed great genetic heterogeneity among R. tropici and R. leguminosarum bv. phaseoli strains and allowed the constitution of genetic clusters, besides indicating the most suitable primers for this characterization. The groups of genetically distinct strains can be used in competitiveness studies to select appropriate Rhizobium strains for bean inoculation in ce...

Isnia Aparecida de Oliveira; Maria José Vasconcellos; Lucy Seldin; Edilson Paiva; Milton Alexandre Vargas; Nadja Maria Horta de Sá

2000-01-01

198

Random amplified polymorphic DNA analysis of effective Rhizobium sp. associated with beans cultivated in brazilian cerrado soils  

Directory of Open Access Journals (Sweden)

Full Text Available Efficient bean nodulating Rhizobium strains, isolated from different Brazilian cerrado soils, were characterized by RAPD. This study showed great genetic heterogeneity among R. tropici and R. leguminosarum bv. phaseoli strains and allowed the constitution of genetic clusters, besides indicating the most suitable primers for this characterization. The groups of genetically distinct strains can be used in competitiveness studies to select appropriate Rhizobium strains for bean inoculation in cerrado soils.

Oliveira Isnia Aparecida de

2000-01-01

199

Numerical Taxonomic Analysis of Some Strains of Rhizobium spp. That Uses a Qualitative Coding of Immunodiffusion Reactions  

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Antigenic relationships among seven strains of Bradyrhizobium japonicum were examined by immunodiffusion reactions, in which cells of each strain were reacted against each of the seven corresponding antisera. Similar analyses were performed with Rhizobium trifolii (28 strains), Rhizobium meliloti (9 strains), and rhizobia of the cowpea miscellany (13 strains). Antigens and antisera were reacted within each species only; serological interspecies cross-reactions were not performed. The results,...

Dudman, William F.; Belbin, Lee

1988-01-01

200

Complete Genome Sequence of the Sesbania Symbiont and Rice Growth-Promoting Endophyte Rhizobium sp. Strain IRBG74  

Science.gov (United States)

Rhizobium sp. strain IRBG74 is the first known nitrogen-fixing symbiont in the Agrobacterium/Rhizobium clade that nodulates the aquatic legume Sesbania sp. and is also a growth-promoting endophyte of wetland rice. Here, we present the sequence of the IRBG74 genome, which is composed of a circular chromosome, a linear chromosome, and a symbiotic plasmid, pIRBG74a.

Crook, Matthew B.; Mitra, Shubhajit; Ane, Jean-Michel

2013-01-01

 
 
 
 
201

Biochemical Analysis of Chickpea Protection Against Fusarium Wilt Afforded by Two Rhizobium Isolates  

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Germinated seeds of two chickpea cultivars ILC482 and INRAT87/1, respectively susceptible and moderately resistant to Fusarium oxysporum f. sp. ciceris (Foc), were preinoculated with a suspension of two Rhizobium isolates PchDMS and Pch43. Three days later, the seedlings were challenged by root dip with a conidial suspension of Foc race 0. The two Rhizobium isolates protected chickpea plants from F. oxysporum infection; the best protection has been obtained ...

2005-01-01

202

Biosynthesis of Rhizobium meliloti lipooligosaccharide Nod factors: NodA is required for an N-acyltransferase activity.  

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Rhizobium bacteria synthesize N-acylated beta-1,4-N-acetylglucosamine lipooligosaccharides, called Nod factors, which act as morphogenic signal molecules to legume roots during development of nitrogen-fixing nodules. The biosynthesis of Nod factors is genetically dependent upon the nodulation (nod) genes, including the common nod genes nodABC. We used the Rhizobium meliloti NodH sulfotransferase to prepare 35S-labeled oligosaccharides which served as metabolic tracers for Nod enzyme activitie...

Atkinson, E. M.; Palcic, M. M.; Hindsgaul, O.; Long, S. R.

1994-01-01

203

Studi Isolasi Bakteri Rhizobium Yang Diinokulasikan Ke Dalam Dolomit Sebagai Pembawa ( Carrier ) Serta Pemanfaatannya Sebagai Pupuk Mikroba  

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Telah dilakukan penelitian tentang isolasi bakteri Rhizobium dari bintil akar putri malu (Mimosa pudica L) dengan Metode Dubey,2006. Bakteri hasil isolasi kemudian diinokulasi ke dalam dolomit dengan perbandingan 1:2 , 1:3, 1:4, 1:5, 1:6. Fungsi dolomit adalah sebagai pembawa (carrier) dalam pemanfaatan Rhizobium sebagai sumber Unsur N untuk tanaman kacang hijau yang diujikan di lapangan. Berdasarkan analisis perhitungan jumlah sel yang dilakukan di Laboratorium Mikrobiologi setelah 2 bulan i...

2010-01-01

204

Biosynthesis of lipooligosaccharide nodulation factors: Rhizobium NodA protein is involved in N-acylation of the chitooligosaccharide backbone.  

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Rhizobium meliloti interacts symbiotically with alfalfa by forming root nodules in which the bacteria fix nitrogen. The Rhizobium nodulation genes nodABC are involved in the synthesis of lipooligosaccharide symbiotic signal molecules, which are mono-N-acylated chitooligosaccharides. These bacterial signals elicit nodule organogenesis in roots of legumes. To elucidate the role of the NodA protein in lipooligosaccharide biosynthesis, we prepared a radiolabeled tetrasaccharide precursor carrying...

Ro?hrig, H.; Schmidt, J.; Wieneke, U.; Kondorosi, E.; Barlier, I.; Schell, J.; John, M.

1994-01-01

205

In vitro sulfotransferase activity of NodH, a nodulation protein of Rhizobium meliloti required for host-specific nodulation.  

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Early stages of nodulation involve the exchange of signals between the bacterium and the host plant. Bacterial nodulation (nod) genes are required for Rhizobium spp. to synthesize lipooligosaccharide morphogens, termed Nod factors. The common nod genes encode enzymes that synthesize the factor core structure, which is modified by host-specific gene products. Here we show direct in vitro evidence that Rhizobium meliloti NodH, a host-specific nodulation gene, catalyzes the transfer of sulfate f...

Ehrhardt, D. W.; Atkinson, E. M.; Faull, K. F.; Freedberg, D. I.; Sutherlin, D. P.; Armstrong, R.; Long, S. R.

1995-01-01

206

Mass Spectrometric Quantification of Indole-3-Acetic Acid in Rhizobium Culture Supernatants: Relation to Root Hair Curling and Nodule Initiation  

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Indole-3-acetic acid (IAA) has been unequivocally identified in culture supernatants of Rhizobium strains by gas chromatography-mass spectrometry. A method for accurately quantitating IAA in bacterial culture supernatants, employing deuterium-labeled IAA as an internal standard, has been developed. Similar IAA concentrations were found in culture supernatants of chosen Rhizobium mutants (defective in nodule formation) and their corresponding parent strains. Since some of the mutants are known...

Badenoch-jones, Jane; Summons, R. E.; Djordjevic, M. A.; Shine, J.; Letham, D. S.; Rolfe, B. G.

1982-01-01

207

Effect of Rhizobial Management upon Rhizobial Population, Nodulation and Growth of Yard Long Beans (Vigna sesquipedalis L.) A New Approach to Maximize Benefits from Rhizobium  

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The work aimed to investigate some benefits derived from Rhizobium technology. The results showed that management methods in retaining native Rhizobium being tested had a tremendous effect on population management, i.e. native Rhizobium could be maintained. However, Rhizobium has preferential level of selectivity to host. KKU 25 yard long bean plants had the highest level of rhizobia population followed by white seeded cultivar at day 30 and thereafter the amount of rhizobia population declin...

Sinsiri, W.; Homchan, J.

2002-01-01

208

First genomic analysis of the broad-host-range Rhizobium sp. LPU83 strain, a member of the low-genetic diversity Oregon-like Rhizobium sp. group.  

Science.gov (United States)

Alfalfa (Medicago sativa) is the most cultivated forage legume for cattle and animal feeding, occupying about 32 million hectares over the world. Management of the N?-fixing symbiosis of this plant to maximize crop production is therefore an important objective. A fundamental constraint to this aim emerges when a moderately low soil pH hampers the establishment of an effective symbiosis with indigenous and/or inoculated rhizobia. Besides the association of alfalfa with Ensifer (Sinorhizobium) meliloti, this legume is able to establish a symbiosis with Ensifer (Sinorhizobium) medicae and with less characterized types of rhizobia, such as the Oregon-like strains, Rhizobium sp. Or191 initially isolated in the USA, and the Rhizobium sp. LPU83 strain, from Argentina. These strains are acid-tolerant, highly competitive for acidic-soil-alfalfa nodulation, but inefficient for biological nitrogen fixation with alfalfa. These features position the Oregon-like rhizobia as strains of potential risk in agricultural soils compared with the efficient symbiont E. meliloti. Moreover, the collected genetic information has revealed that the genomic structure of these rhizobial isolates is complex in terms of sequence similarities shared with other rhizobia. Such a "patched" genetic composition has obviously imposed severe restrictions to the classical taxonomy of these rhizobia. In this work we summarize the accumulated knowledge about the Oregon-like rhizobia and present a phylogenetic analysis based on genome sequence data of Rhizobium sp. LPU83 obtained by a high-throughput sequencing on the Genome Sequencer FLX Titanium platform. The accessibility of the complete genomic sequence will release up more experimental possibilities since this information will then enable biochemical studies as well as proteomics and transcriptomics approaches. PMID:21329739

Tejerizo, Gonzalo Torres; Del Papa, María Florencia; Draghi, Walter; Lozano, Mauricio; Giusti, María de Los Ángeles; Martini, Carla; Salas, María Eugenia; Salto, Ileana; Wibberg, Daniel; Szczepanowski, Rafael; Weidner, Stefan; Schlüter, Andreas; Lagares, Antonio; Pistorio, Mariano

2011-08-20

209

Caracterização química dos géis produzidos pelas bactérias diazotróficas Rhizobium tropici e Mesorhizobium sp. Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp.  

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Full Text Available The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPS RT and Mesorhizobium sp (EPS MR are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose (~ 1%. Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPS RT and EPS MR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, ¹H and 13C-NMR.

Nilson Kobori Monteiro

2012-01-01

210

Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp; Caracterizacao quimica dos geis produzidos pelas bacterias diazotroficas Rhizobium tropici e Mesorhizobium sp.  

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The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPSRT) and Mesorhizobium sp (EPSMR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose ({approx} 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPSRT and EPSMR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, {sup 1}H and {sup 13}C-NMR. (author)

Monteiro, Nilson Kobori [Departamento de Engenharia e Tecnologia de Alimentos, Instituto de Biociencias, Letras e Ciencias Exatas, Universidade Estadual Paulista, Sao Jose do Rio Preto - SP (Brazil); Aranda-Selverio, Gabriel; Exposti, Diego Tadeu Degli; Silva, Maria de Lourdes Corradi da [Departamento de Fisica, Quimica e Biologia, Faculdade de Ciencias e Tecnologia, Universidade Estadual Paulista, Presidente Prudente - SP (Brazil); Lemos, Eliana Gertrudes Macedo; Campanharo, Joao Carlos [Departamento de Tecnologia, Faculdade de Ciencias Agrarias e Veterinaria, Universidade Estadual Paulista, Jaboticabal - SP (Brazil); Silveira, Joana Lea Meira [Departamento de Bioquimica e Biologia Molecular, Universidade Federal do Parana, Curitiba - PR (Brazil)

2012-07-01

211

Isolation and properties of an ultraviolet-sensitive mutant of Rhizobium trifolii  

International Nuclear Information System (INIS)

In an attempt to isolate a strain of Rhizobium trifolii which could be highly mutated by ultraviolet light (u.v.), a u.v.-sensitive mutant was isolated using a semi-selective procedure. The mutant was not only 85 times more sensitive than the wild-type to the lethal effects of u.v., but was mutated at u.v. doses which had little mutagenic effect on the wild-type. Its sensitivity to the mutagenic agents methyl methanesulphonate and gamma rays was unaltered, but its spontaneous mutation frequencies for two antibiotic resistances were increased. The mutation conferring u.v. sensitivity was mapped on the chromosome of Rhizobium leguminosarum 300 in a position between the markers ser-2 and ade-88. Unsuccessful attempts were made to transfer into the u.v.-sensitive mutant any one of a number of plasmids known to decrease the lethality of u.v. and enhance its mutagenicity. (author)

1981-01-01

212

[Production of L(+)-tartaric acid by immobilized Rhizobium strain BK-20].  

Science.gov (United States)

The cis-epoxysuccinate hydrolase (CESH) from Rhizobium strain BK-20 is the key enzyme for L(+)-tartaric acid production. To establish a highly efficient and stable production process, we first optimized the enzyme production from Rhizobium strain BK-20, and then developed an immobilized cell-culture process for sustained production of L(+)-tartaric acid. The enzyme activity of free cells reached (3 498.0 +/- 142.6) U/g, and increased by 643% after optimization. The enzyme activity of immobilized cells reached (2 817.2 +/- 226.7) U/g, under the optimal condition with sodium alginate as carrier, cell concentration at 10% (W/V) and gel concentration at 1.5% (W/V). The immobilized cells preserved high enzyme activity and normal structure after 10 repeated batches. The conversion rate of the substrate was more than 98%, indicating its excellent production stability. PMID:24941753

Lan, Xiang; Bao, Wenna; Pan, Haifeng; Xie, Zhipeng; Zhang, Jianguo

2014-02-01

213

Efficacy of Various Rhizobium Strains to Different Varieties of Groundnut (Arachis hypogea L.  

Directory of Open Access Journals (Sweden)

Full Text Available Groundnut variety BARD-699 produced significantly the most promising yield than that of variety BARI-89 at Attock, Fatehjang and NARC, Islamabad. Rhizobium strains, NC-92 was found to be less efficient as compared to TAL-1000; TAL-1371. Nodule dry mass and number of pods per plant were much higher than that of control treatment. Although a significant difference in growth and yield of both the varieties due to Rhizobium inoculation was observed but on average basis TAL-1000 and TAL-1371 gave significantly better response for both the varieties in improving growth and yield at all sites. Nevertheless, future prospects for groundnut production are good in Pakistan if the farmers are realized to practice inoculation technology in their fields.

M. Aslam

1999-01-01

214

Genotypic Characterisation of Indigenous Rhizobium leguminosarum bv. viciae Field Population in Croatia  

Directory of Open Access Journals (Sweden)

Full Text Available Genetic diversity of thirteen Rhizobium legumnosarum bv. viciae strains isolated from different field sites in continental part of Croatia was investigated. All rhizobial isolates were obtained either from plants grown in pots containing soil samples or from field grown plants. The strains were analyzed for DNA polymorphism using two DNA fingerprinting methods - randomly amplified polymorphic DNA (RAPD-PCR and repetitive extragenomic palindromic- PCR (rep-PCR. Both methods resulted in very similar grouping of strains. Cluster analysis of rep- and RAPD-PCR profi les showed significant differences among Rh. leguminosarum bv. viciae isolates. The highest differences were detected among reference strains and all field isolates revealing considerable genetic diversity of rhizobial field populations. These results suggest the presence of adapted indigenous Rhizobium leguminosarum bv. viciae strains, probably with higher competitive ability, whose symbiotic properties have to be evaluated in further investigations.

Mihaela Blažinkov

2007-06-01

215

Rhizobium flavum sp. nov., a triazophos-degrading bacterium isolated from soil under the long-term application of triazophos.  

Science.gov (United States)

A Gram-stain-negative, non-motile, pale yellow, rod-shaped bacterial strain, YW14(T), was isolated from soil and its taxonomic position was investigated by a polyphasic study. Strain YW14(T) did not form nodules on three different legumes, and the nodD and nifH genes were not detected by PCR. Strain YW14(T) contained Q-10 as the predominant ubiquinone. The major cellular fatty acid was C18?:?1?7c. Phylogenetic analyses based on 16S rRNA gene sequences and seven housekeeping gene sequences (recA, atpD, glnII, gyrB, rpoB, dnaK and thrC) showed that strain YW14(T) belonged to the genus Rhizobium. Strain YW14(T) showed 16S rRNA gene sequence similarity of 93.4-97.3?% to the type strains of recognized species of the genus Rhizobium. DNA-DNA relatedness between strain YW14(T) and the type strains of Rhizobium sullae IS123(T) and Rhizobium yanglingense CCBAU 71623(T) was 19.6-25.7?%, indicating that strain YW14(T) was distinct from them genetically. Strain YW14(T) could also be differentiated from these phylogenetically related species of the genus Rhizobium by various phenotypic properties. On the basis of phenotypic properties, phylogenetic distinctiveness and genetic data, strain YW14(T) is considered to represent a novel species of the genus Rhizobium, for which the name Rhizobium flavum sp. nov. is proposed. The type strain is YW14(T) (?=?KACC 17222(T)?=?CCTCC AB2013042(T)). PMID:24639241

Gu, Tao; Sun, Li Na; Zhang, Jun; Sui, Xin Hua; Li, Shun Peng

2014-06-01

216

Underexpression of Ap from R-Plasmids in Fast-Growing Rhizobium Species  

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The presence of the plasmid RP1 in the cells of Rhizobium leguminosarum strains Rld1, 300, and 248, R. phaseoli 1233, R. trifolii strains T1 and 6661, and R. meliloti 4013 was found to appreciably increase bacterial resistance toward kanamycin and tetracycline but not toward ampicillin. The presence of 16 other R-plasmids in R. leguminosarum was also found to either not increase or only marginally increase bacterial resistance toward ampicillin. It appears now that underexpression of the plas...

1984-01-01

217

Effect of salt stress and phosphorus deficiency in mutants of rhizobium obtained by gamma irradiation  

International Nuclear Information System (INIS)

Two strains of Rhizobium: Rhizobium Tropici and Mesorhizobium Ciceri nodulating respectively common bean and chickpea were treated by gamma irradiation (60Co) source. Radiosensibility analysis showed that 800 Gy was the biggest dose supported by these two strains. We isolated gamma irradiated resistant strain in order to select mutant of them which can supported salt stress and phosphorus deficiency. Salinity analysis showed that Mesorhizobium Ciceri 835 strain, can tolerate up to 18g/l (273 mM NaCl) of salt, whereas, their irradiation mutants tolerate salinity up to 33g/l (564mM. NaCl) Rhizobium Tropici CIAT899 can survive at 20g/l (342 mM) either for control strain or mutants. Analysis of phosphorus deficiency showed that either Rhizobium Tropici CIAT899, or Mesorhizobium Ciceri 835 can survive in medium without phosphore. Our results permit us to screen mutants tolerant to these stresses wide spread in Mediterranean soil. In this study, we choose two mutants strains irradiated by 700Gy and two mutants irradiated by 800Gy in each species, these mutants were characterized by their best growth compared with their reference strains. Our results showed that Gamma irradiation modified antibiotic resistance, such as kanamicyne, tetracycline, vancomicyne, streptomicyne, penicilline, either at 700Gy or at 800Gy, we obtained significant modification of response and persistence of penicilline resistance. Biochemical analysis showed that these strains had a variable superoxide dismutase (SOD, E.C. 1.15.1.1) and catalase (CAT, E.C. 1.11.1.6) activities essentially in Mesorhizobium Ciceri 835 mutant strains, these two enzymatic antioxidants was suggested to play an important role in environmental stress tolerance. (author)

2008-08-12

218

Evidence of an American Origin for Symbiosis-Related Genes in Rhizobium lusitanum ?  

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Randomly amplified polymorphic DNA (RAPD) analysis was used to investigate the diversity of 179 bean isolates recovered from six field sites in the Arcos de Valdevez region of northwestern Portugal. The isolates were divided into 6 groups based on the fingerprint patterns that were obtained. Representatives for each group were selected for sequence analysis of 4 chromosomal DNA regions. Five of the groups were placed within Rhizobium lusitanum, and the other group was placed within R. tropici...

Valverde, Angel; Vela?zquez, Encarna; Cervantes, Emilio; Igual, Jose? M.; Berkum, Peter

2011-01-01

219

Symbiotic Characteristics and Rhizobium Requirements of a Leucaena leucocephala × Leucaena diversifolia Hybrid and Its Parental Genotypes  

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In 56-day-old plants, Leucaena leucocephala and its hybrid with L. diversifolia showed 100% more total N than did L. diversifolia. Significant (P < 0.01) host-inoculation interaction in total N was 14.4% of the total phenotypic variation. The most effective and competitive Rhizobium sp. for the leucaenas was TAL 1145. Three-strain mixed inoculation was inferior to TAL 1145 alone.

Somasegaran, P.; Martin, R. B.

1986-01-01

220

Foliar Chlorosis in Symbiotic Host and Nonhost Plants Induced by Rhizobium tropici Type B Strains  

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Rhizobium tropici CIAT899 induced chlorosis in the leaves of its symbiotic hosts, common bean (Phaseolus vulgaris L.), siratro (Macroptilium atropurpureum Urb.), and Leucaena leucocephala (Lam.) de Wit. Chlorosis induction by strains CIAT899 and CT9005, an exopolysaccharide-deficient mutant of CIAT899, required carbon substrate. When the bacteria were added at planting in a solution of mannitol (50 g/liter), as few as 103 cells of CIAT899 were sufficient to induce chlorosis in bean plants. Al...

O Connell, Kevin P.; Handelsman, Jo

1993-01-01

 
 
 
 
221

Competition Among Rhizobium spp. for Nodulation of Leucaena leucocephala in Two Tropical Soils †  

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The successful nodulation of legumes by a Rhizobium strain is determined by the competitive ability of that strain against the mixture of other native and inoculant rhizobia. Competition among six Leucaena rhizobial strains in single and multistrain inoculants were studied. Field inoculation trials were conducted in an oxisol and a mollisol soil, both of which contained indigenous Leucaena-nodulating rhizobia. Strain-specific fluorescent antibodies were used for the identification of the stra...

Moawad, H.; Bohlool, B. B.

1984-01-01

222

Nitrogen-Fixing Nodules with Ensifer adhaerens Harboring Rhizobium tropici Symbiotic Plasmids  

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Ensifer adhaerens is a soil bacterium that attaches to other bacteria and may cause lysis of these other bacteria. Based on the sequence of its small-subunit rRNA gene, E. adhaerens is related to Sinorhizobium spp. E. adhaerens ATCC 33499 did not nodulate Phaseolus vulgaris (bean) or Leucaena leucocephala, but with symbiotic plasmids from Rhizobium tropici CFN299 it formed nitrogen-fixing nodules on both hosts. The nodule isolates were identified as E. adhaerens isolates by growth on selectiv...

Rogel, M. Antonio; Herna?ndez-lucas, Ismael; Kuykendall, L. David; Balkwill, David L.; Martinez-romero, Esperanza

2001-01-01

223

Classification of the uptake hydrogenase-positive (Hup+) bean rhizobia as Rhizobium tropici.  

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Phenotypic and genetic characterization indicated that Hup+ bean rhizobial strains are type IIA and type IIB Rhizobium tropici. The Hup+ strain USDA 2840, which did not cluster with either of the two types of R. tropici in a restriction fragment length polymorphism analysis, had electrophoretic patterns of PCR products generated with primers for repetitive extragenic palindromic and enterobacterial repetitive intergeneric consensus sequences similar to those of three reference strains of R. t...

Berkum, P.; Navarro, R. B.; Vargas, A. A.

1994-01-01

224

Rhizobium (Agrobacterium) radiobacter Identified as a Cause of Chronic Endophthalmitis Subsequent to Cataract Extraction  

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Herein, we report a case of chronic endophthalmitis caused by a ceftazidime-resistant Rhizobium radiobacter strain in a 62-year-old male. The patient underwent an uneventful cataract extraction of the right eye a week prior to the appearance of symptoms (pain, redness, and blurring vision) which developed following a golf outing. Upon admission the patient received an emergency vitrectomy. The patient remained symptomatic, and R. radiobacter was isolated repeatedly from vitreous fluid culture...

2003-01-01

225

Canonical ordered cosmid library of the symbiotic plasmid of Rhizobium species NGR234.  

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Many of the bacterial genes involved in nodulation (nod) and nitrogen fixation (nif) are dispersed over the 500-kilobase plasmid pNGR234a of the broad host-range Rhizobium species NGR234. As a first step toward generating a complete physical and genetic map of the plasmid, a full overlapping collection of cosmids was derived from a total genomic library. Clones were aligned by combining fingerprinting, hybridization, and pulsed-field gel electrophoresis data. Symbiotic loci were localized by ...

Perret, X.; Broughton, W. J.; Brenner, S.

1991-01-01

226

Regulation and effects of the type-three secretion system of "Rhizobium" species NGR234  

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"Rhizobium" sp. NGR234 establishes a symbiotic interaction with many legume plants. Regulatory cascade which is trigged by plant produced flavonoids is intricate and numerous factors participate including several transcriptional regulators to control the synthesis of Nod-factors, polysaccharides and T3SS. The striking effects of the NodV (sensor) and NodW (regulator) two-component system were observed on key symbiosis regulators of the regulatory cascade in the absence of flavonoids. ...

Kambara, Kumiko; Broughton, William John; Deakin, William James

2008-01-01

227

NolL of Rhizobium sp. Strain NGR234 Is Required for O-Acetyltransferase Activity  

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Following (iso)flavonoid induction, nodulation genes of the symbiotic nitrogen-fixing bacterium Rhizobium sp. strain NGR234 elaborate a large family of lipooligosaccharidic Nod factors (NodNGR factors). When secreted into the rhizosphere of compatible legumes, these signal molecules initiate root hair deformation and nodule development. The nonreducing glucosamine residue of NodNGR factors are N acylated, N methylated, and mono- or biscarbamoylated, while position C-6 of the reducing extremit...

Berck, S.; Perret, X.; Quesada-vincens, D.; Prome?, J. -c; Broughton, W. J.; Jabbouri, S.

1999-01-01

228

Three Replicons of Rhizobium sp. Strain NGR234 Harbor Symbiotic Gene Sequences  

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Rhizobium sp. strain NGR234 contains three replicons: the symbiotic plasmid or pNGR234a, a megaplasmid (pNGR234b), and the chromosome. Symbiotic gene sequences not present in pNGR234a were analyzed by hybridization. DNA sequences homologous to the genes fixLJKNOPQGHIS were found on the chromosome, while sequences homologous to nodPQ and exoBDFLK were found on pNGR234b.

Flores, Margarita; Mavingui, Patrick; Girard, Lourdes; Perret, Xavier; Broughton, William J.; Marti?nez-romero, Esperanza; Da?vila, Guillermo; Palacios, Rafael

1998-01-01

229

Cryptic plasmid and rifampin resistance in Rhizobium meliloti influencing nodulation competitiveness.  

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An assessment was made of the relative contributions of a spontaneous mutation to rifampin resistance and a cryptic plasmid, pTA2, to competitive nodulation of Medicago sativa by a strain of Rhizobium meliloti. This was facilitated by use of rifampin-resistant derivatives of this strain in which pTA2 was originally present, cured, or reintroduced. Both curing of pTA2 and spontaneous mutation to rifampin resistance significantly influenced nodulating competitiveness, but the effect of rifampin...

Bromfield, E. S.; Lewis, D. M.; Barran, L. R.

1985-01-01

230

Coexistence of Burkholderia, Cupriavidus, and Rhizobium sp. Nodule Bacteria on two Mimosa spp. in Costa Rica  

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rRNA gene sequencing and PCR assays indicated that 215 isolates of root nodule bacteria from two Mimosa species at three sites in Costa Rica belonged to the genera Burkholderia, Cupriavidus, and Rhizobium. This is the first report of Cupriavidus sp. nodule symbionts for Mimosa populations within their native geographic range in the neotropics. Burkholderia spp. predominated among samples from Mimosa pigra (86% of isolates), while there was a more even distribution of Cupriavidus, Burkholderia...

Barrett, Craig F.; Parker, Matthew A.

2006-01-01

231

Role of divalent cations in the subunit associations of complex flagella from Rhizobium meliloti.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rhizobium meliloti, a symbiotic, nitrogen-fixing soil bacterium with complex flagella, as well as other members of the family Rhizobiaceae, rapidly lost motility when suspended in buffers lacking divalent cations but retained good motility in buffers containing calcium, magnesium, barium, or strontium. Loss of motility was associated with loss of flagella from the cells. Analysis of flagella by sedimentation, gel electrophoresis, and electron microscopy revealed that removal of divalent catio...

Robinson, J. B.; Tuovinen, O. H.; Bauer, W. D.

1992-01-01

232

The genome of Rhizobium leguminosarum has recognizable core and accessory components  

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Background: Rhizobium leguminosarum is an alpha-proteobacterial N-2-fixing symbiont of legumes that has been the subject of more than a thousand publications. Genes for the symbiotic interaction with plants are well studied, but the adaptations that allow survival and growth in the soil environment are poorly understood. We have sequenced the genome of R. leguminosarum biovar viciae strain 3841. Results: The 7.75 Mb genome comprises a circular chromosome and six circular plasmids, with 61% G+...

Young, J. P. W.; Crossman, L. C.; Johnston, A. W. B.; Thomson, N. R.; Ghazoui, Z. F.; Hull, K. H.; Wexler, M.; Curson, A. R. J.; Todd, J. D.; Poole, P. S.; Mauchline, T. H.; East, A. K.; Quail, M. A.; Churcher, C.; Arrowsmith, C.

2006-01-01

233

Assignment of symbiotic developmental phenotypes to common and specific nodulation (nod) genetic loci of Rhizobium meliloti.  

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Rhizobium meliloti nodulation (nod) genes required for specific infection and nodulation of alfalfa have been cloned. Transposon Tn5 mutagenesis defined three nod regions spanning 16 kilobases of the pSym megaplasmid. Genetic and cytological studies of 62 nodulation-defective mutants allowed the assignment of symbiotic developmental phenotypes to common and specific nod loci. Root hair curling was determined by both common (region I) and specific (region III) nod transcription units; locus II...

Debelle?, F.; Rosenberg, C.; Vasse, J.; Maillet, F.; Martinez, E.; De?narie?, J.; Truchet, G.

1986-01-01

234

Influence of Glycine spp. on Competitiveness of Bradyrhizobium japonicum and Rhizobium fredii  

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The displacement of indigenous Bradyrhizobium japonicum in soybean nodules with more effective strains offers the possibility of enhanced N2 fixation in soybean (Glycine max (L.) Merr.). Our objective was to determine whether the wild soybean (G. soja Sieb. & Zucc.) genotype PI 468397 would cause reduced competitiveness of important indigenous B. japonicum strains USDA 31, 76, and 123 and thereby permit nodulation by Rhizobium fredii, the fast-growing microsymbiont of soybean. In an initial e...

Cregan, P. B.; Keyser, H. H.

1988-01-01

235

Effect of Light and Organic Acids on Oxygen Uptake by BTAi 1, a Photosynthetic Rhizobium  

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A photosynthetic rhizobium, strain BTAi 1, was cultured ex planta to investigate its photosynthetic-respiratory system and the response of this interactive system to light quantity and quality and to the addition of organic acids. Oxygen uptake, as measured with an oxygen electrode, is diminished upon illumination, with the amount of decrease related to light intensity. This oxygen-sparing effect is correlated with the wavelengths of light that are associated with bacteriochlorophyll absorban...

1992-01-01

236

Relationships between C4 dicarboxylic acid transport and chemotaxis in Rhizobium meliloti.  

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The relationship between chemotaxis and transport of C4 dicarboxylic acids was analyzed with Rhizobium meliloti dct mutants defective in one or all of the genes required for dicarboxylic acid transport. Succinate, malate, and fumarate were moderately potent chemoattractants for wild-type R. meliloti and appeared to share a common chemoreceptor. While dicarboxylate transport is inducible, taxis to succinate was shown to be constitutive. Mutations in the dctA and dctB genes both resulted in the...

Robinson, J. B.; Bauer, W. D.

1993-01-01

237

Chemotaxis of Rhizobium meliloti towards Nodulation Gene-Inducing Compounds from Alfalfa Roots  

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Luteolin, a flavone present in seed exudates of alfalfa, induces nodulation genes (nod) in Rhizobium meliloti and also serves as a biochemically specific chemoattractant for the bacterium. The present work shows that R. meliloti RCR2011 is capable of very similar chemotactic responses towards 4?,7-dihydroxyflavone, 4?,7-Dihydroxyflavanone, and 4,4?-dihydroxy-2-methoxychalcone, the three principal nod gene inducers secreted by alfalfa roots. Chemotactic responses to the root-secreted nod...

Dharmatilake, Amitha J.; Bauer, Wolfgang D.

1992-01-01

238

Chemotaxis of Rhizobium meliloti to the plant flavone luteolin requires functional nodulation genes.  

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Luteolin is a phenolic compound from plants that acts as a potent and specific inducer of nodABC gene expression in Rhizobium meliloti. We have found that R. meliloti RCR2011 exhibits positive chemotaxis towards luteolin. A maximum chemotactic response was observed at 10(-8) M. Two closely related flavonoids, naringenin and apigenin, were not chemoattractants. The presence of naringenin but not apigenin abolished chemotaxis of R. meliloti towards luteolin. A large deletion in the nif-nod regi...

Caetano-anolle?s, G.; Crist-estes, D. K.; Bauer, W. D.

1988-01-01

239

Hydroxylated ornithine lipids increase stress tolerance in Rhizobium tropici CIAT899  

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Ornithine lipids (OLs) are widespread among gram-negative bacteria. Their basic structure consists of a 3-hydroxy fatty acyl group attached in amide linkage to the ?-amino group of ornithine and a second fatty acyl group ester-linked to the 3-hydroxy position of the first fatty acid. OLs can be hydroxylated within the secondary fatty acyl moiety and this modification has been related to increased stress tolerance. Rhizobium tropici, a nodule-forming ?-proteobacterium known for its stress to...

2011-01-01

240

Nitrogen fixation by Rhizobium leguminosarum PRE; a genetical and biochemical approach.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nitrogen fix ation by Rhizobium and Bradyrhizobium bacteria in symbiosis with their leguminous host plants forms an attractive alternative for the industrial production of nitrogenous fertilizers, both from an economic as well as an enviromnental point of view, and is the topic of many scientific research programs nowadays. Ultimate goals in many of these programs are improving the efficiency of nitrogen fix ation, the extension of the host range of the bacteria to important, non-leguminous c...

Klein Lankhorst, R.

1989-01-01

 
 
 
 
241

Isolation and characterization of transposon Tn5-induced symbiotic mutants of Rhizobium loti.  

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Rhizobium loti NZP2037 and NZP2213, each cured of its single large indigenous plasmid, formed effective nodules on Lotus spp., suggesting that the symbiotic genes are carried on the chromosome of these strains. By using pSUP1011 as a vector for introducing transposon Tn5 into R. loti NZP2037, symbiotic mutants blocked in hair curling (Hac), nodule initiation (Noi), bacterial release (Bar), and nitrogen fixation (Nif/Cof) on Lotus pedunculatus were isolated. Cosmids complementing the Hac, Noi,...

1985-01-01

242

Transformation of pWWO in Rhizobium leguminosarum DPT to Engineer Toluene Degrading Ability for Rhizoremediation  

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Rhizoremediation of organic xenobiotics is based on interactions between plants and their associated micro-organisms. The present work was designed to engineer a bacterial system having toluene degradation ability along with plant growth promoting characteristics for effective rhizoremediation. pWWO harboring the genes responsible for toluene breakdown was isolated from Pseudomonas putida MTCC 979 and successfully transformed in Rhizobium DPT. This resulted in a bacterial strain (DPTT) which ...

Goel, Garima; Pandey, Piyush; Sood, Anchal; Bisht, Sandeep; Maheshwari, D. K.; Sharma, G. D.

2012-01-01

243

Increased Effectiveness of Competitive Rhizobium Strains upon Inoculation of Cajanus cajan  

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A field study was conducted in lysimeters containing 15N-enriched soil to determine the effects of four competitive rhizobium strains upon yield parameters of pigeon peas (Cajanus cajan). The greatest differences observed were in seed yields; strain P132 effected the highest seed yield (121 ± 20 g per plant), and the control strain (indigenous rhizobia) effected the lowest yield (43.9 ± 8 g per plant). With the exception of seeds and pods, the dry matter weights were not different. Although...

Hernandez, B. S.; Poth, M.; Focht, D. D.

1987-01-01

244

Succinate-Induced Morphology of Rhizobium trifolii 0403 Resembles That of Bacteroids in Clover Nodules †  

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Morphological changes which accompany nutrient enrichment of Rhizobium trifolii 0403 were studied. Assays of cell number and size coupled with scanning electron microscopy and immunofluorescence microscopy showed that succinate induces cells to stop dividing in vitro and to swell either in the cell center or at one cell pole. The extent and frequency of in vitro cell swelling were in direct relation to the concentration of succinate added to the enrichment medium. The in vitro swelling of cel...

Urban, James E.; Dazzo, Frank B.

1982-01-01

245

Perception and action of nod factors in Rhizobium-legume symbiosis.  

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Rhizobium bacteria are able to invade the roots of their leguminous hosts and trigger the formation of a new organ, the root nodule. In these nodules the bacteria are hosted in the proper environment for fixing atmospheric nitrogen into ammonia, making plant growth independent of nitrogen compounds from the soil. The interaction between the bacterium and the host plant starts with a signal exchange, when flavonoids excreted by the plant induce the transcription of bacterial nodulation (nod) g...

Heidstra, R.

1997-01-01

246

Trehalose Biosynthesis in Rhizobium leguminosarum bv. trifolii and Its Role in Desiccation Tolerance?  

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Rhizobium leguminosarum bv. trifolii forms nitrogen-fixing root nodules on the pasture legume Trifolium repens, and T. repens seed is often coated with a compatible R. leguminosarum bv. trifolii strain prior to sowing. However, significant losses in bacterial viability occur during the seed-coating process and during storage of the coated seeds, most likely due to desiccation stress. The disaccharide trehalose is known to function as an osmoprotectant, and trehalose accumulation due to de nov...

Mcintyre, Helen J.; Davies, Holiday; Hore, Timothy A.; Miller, Simon H.; Dufour, Jean-pierre; Ronson, Clive W.

2007-01-01

247

Rhizobium meliloti mutants deficient in phospholipid N-methyltransferase still contain phosphatidylcholine.  

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Phosphatidylcholine (PC) is the major membrane-forming phospholipid in eukaryotes. In addition to this structural function, PC is thought to play a major role in lipid turnover and signalling in eukaryotic systems. In prokaryotes, only some groups of bacteria, among them the members of the family Rhizobiaceae, contain PC. To understand the role of PC in bacteria, we have studied Rhizobium meliloti 1021, which is able to form nitrogen-fixing nodules on its legume host plants and therefore has ...

Rudder, K. E.; Thomas-oates, J. E.; Geiger, O.

1997-01-01

248

Eukaryotic control on bacterial cell cycle and differentiation in the Rhizobium–legume symbiosis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Symbiosis between legumes and Rhizobium bacteria leads to the formation of root nodules where bacteria in the infected plant cells are converted into nitrogen-fixing bacteroids. Nodules with a persistent meristem are indeterminate, whereas nodules without meristem are determinate. The symbiotic plant cells in both nodule types are polyploid because of several cycles of endoreduplication (genome replication without mitosis and cytokinesis) and grow consequently to extreme sizes. Here we demons...

Mergaert, Peter; Uchiumi, Toshiki; Alunni, Benoi?t; Evanno, Gwe?nae?lle; Cheron, Ange?lique; Catrice, Olivier; Mausset, Anne-elisabeth; Barloy-hubler, Fre?de?rique; Galibert, Francis; Kondorosi, Adam; Kondorosi, Eva

2006-01-01

249

Exopolysaccharide-deficient mutants of Rhizobium meliloti that form ineffective nodules.  

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By screening with the fluorescent stain Calcofluor, we have isolated 26 independent transposon Tn5 insertion mutants of Rhizobium meliloti that are deficient in the production of a known extracellular polysaccharide (Exo-). The mutants belonged to six distinct genetic groups based on the ability of their Exo- phenotype to be complemented by different recombinant plasmids from a R. meliloti clone bank. With few exceptions, all of the mutants formed ineffective (non-nitrogen-fixing) nodules on ...

Leigh, J. A.; Signer, E. R.; Walker, G. C.

1985-01-01

250

Rhizobium meliloti mutants that overproduce the R. meliloti acidic calcofluor-binding exopolysaccharide.  

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The acidic Calcofluor-binding exopolysaccharide of Rhizobium meliloti Rm1021 plays one or more critical roles in nodule invasion and possibly in nodule development. Two loci, exoR and exoS, that affect the regulation of synthesis of this exopolysaccharide were identified by screening for derivatives of strain Rm1021 that formed mucoid colonies that fluoresced extremely brightly under UV light when grown on medium containing Calcofluor. The exopolysaccharide produced in large quantities by the...

Doherty, D.; Leigh, J. A.; Glazebrook, J.; Walker, G. C.

1988-01-01

251

Characterization of polysaccharides of Rhizobium meliloti exo mutants that form ineffective nodules.  

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Mutants of Rhizobium meliloti SU47 with defects in the production of the Calcofluor-binding expolysaccharide succinoglycan failed to gain entry into alfalfa root nodules. In order to define better the polysaccharide phenotypes of these exo mutants, we analyzed the periplasmic oligosaccharide cyclic (1-2)-beta-D-glucan and lipopolysaccharide (LPS) in representative mutants. The exoC mutant lacked the glucan and had abnormal LPS which appeared to lack a substantial portion of the O side chain. ...

Leigh, J. A.; Lee, C. C.

1988-01-01

252

Osmotic control of glycine betaine biosynthesis and degradation in Rhizobium meliloti.  

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Intracellular accumulation of glycine betaine has been shown to confer an enhanced level of osmotic stress tolerance in Rhizobium meliloti. In this study, we used a physiological approach to investigate the mechanism by which glycine betaine is accumulated in osmotically stressed R. meliloti. Results from growth experiments, 14C labeling of intermediates, and enzyme activity assays are presented. The results provide evidence for the pathway of biosynthesis and degradation of glycine betaine a...

Smith, L. T.; Pocard, J. A.; Bernard, T.; Le Rudulier, D.

1988-01-01

253

Hypoosmotic adaptation in Rhizobium meliloti requires beta-(1----2)-glucan.  

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beta-(1----2)-Glucan, an unusual cyclic oligosaccharide, can be isolated from the periplasm of bacteria belonging to the family Rhizobiaceae. Data presented here suggest that the periplasmic beta-(1----2)-glucan of Rhizobium meliloti plays a major role in osmotic adaptation. First, growth of R. meliloti in a low-osmolarity medium causes a large accumulation of periplasmic beta-(1----2)-glucan. Second, mutations in the ndv genes, which prevent this accumulation of beta-(1----2)-glucan, reduce ...

Dylan, T.; Helinski, D. R.; Ditta, G. S.

1990-01-01

254

Influence of Azospirillum Strains on the Nodulation of Clovers by Rhizobium Strains  

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Mixed cultures of several Azospirillum and Rhizobium trifolii strains caused either an inhibition or stimulation of nodule formation on plant hosts as compared with nodulation of plants inoculated with R. trifolii alone. Azospirillum strains affected the nodulation process at a precise cell ratio (R. trifolii/Azospirillum cells) and time of inoculation. All Azospirillum strains used showed a variation in their ability to inhibit or enhance nodulation by R. trifolii strains. When nonviable cel...

Plazinski, Jacek; Rolfe, Barry G.

1985-01-01

255

Rhizobium symbiotic genes required for nodulation of legume and nonlegume hosts  

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Parasponia, a woody member of the elm family, is the only nonlegume genus whose members are known to form an effective nitrogen-fixing symbiosis with Bradyrhizobium or Rhizobium species. The Bradyrhizobium strain Rp501, isolated from Parasponia nodules, also nodulates the legumes siratro (Macroptilium atropurpureum) and cowpea (Vigna unguiculata). To test whether some of the same genes are involved in the early stages of legume and nonlegume nodulation, we generated transposon Tn5 insertions ...

Marvel, Deborah J.; Torrey, John G.; Ausubel, Frederick M.

1987-01-01

256

Construction of a Symbiotically Effective Strain of Rhizobium leguminosarum bv. trifolii with Increased Nodulation Competitiveness  

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Genes involved in nodulation competitiveness (tfx) were inserted by marker exchange into the genome of the effective strain Rhizobium leguminosarum bv. trifolii TA1. Isogenic strains of TA1 were constructed which differed only in their ability to produce trifolitoxin, an antirhizobial peptide. Trifolitoxin production by the ineffective strain R. leguminosarum bv. trifolii T24 limited nodulation of clover roots by trifolitoxin-sensitive strains of R. leguminosarum bv. trifolii. The trifolitoxi...

Triplett, Eric W.

1990-01-01

257

Specific phases of root hair attachment in the Rhizobium trifolii-clover symbiosis.  

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The time course and orientation of attachment of Rhizobium trifolii 0403 to white clover root hairs was examined in slide cultures by light and electron microscopy. Inocula were grown for 5 days on defined BIII agar medium and represented the large subpopulation of fully encapsulated single cells which uniformly bind the clover lectin trifoliin A. When 10(7) cells or more were added per seedling, bacteria attached within minutes, forming randomly oriented clumps at the root hair tips. Several...

Dazzo, F. B.; Truchet, G. L.; Sherwood, J. E.; Hrabak, E. M.; Abe, M.; Pankratz, S. H.

1984-01-01

258

Scanning Electron Microscopy of Rhizobium trifolii Infection Sites on Root Hairs of White Clover  

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White clover root hairs which were inoculated with Rhizobium trifolii 4S (infectious strain) contained infection threads which were observed by light microscopy and scanning electron microscopy. Three morphological types of root hairs retaining infection threads were recognized. The bacteria were strongly attached between the surfaces of two plant cell walls as follows: between surfaces of a root hair tip curled back on itself, between a protuberance from a root hair and its cell surface, or ...

Higashi, Shiro; Abe, Mikiko

1980-01-01

259

Respiratory control determines respiration and nitrogenase activity of Rhizobium leguminosarum bacteroids.  

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The relationship between the O2 input rate into a suspension of Rhizobium leguminosarum bacteroids, the cellular ATP and ADP pools, and the whole-cell nitrogenase activity during L-malate oxidation has been studied. It was observed that inhibition of nitrogenase by excess O2 coincided with an increase of the cellular ATP/ADP ratio. When under this condition the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) was added, the cellular ATP/ADP ratio was lowered while nitrogenase rega...

Haaker, H.; Szafran, M.; Wassink, H.; Klerk, H.; Appels, M.

1996-01-01

260

Biosynthesis and degradation of nodule-specific Rhizobium loti compounds in Lotus nodules.  

Science.gov (United States)

Two nodule-specific Rhizobium loti compounds were identified in Lotus tenuis and Lotus pedunculatus nodules induced by strain NZP2037. One, a silver nitrate-positive cation called rhizolotine, has been characterized as the riboside of a novel alpha-hydroxyimino acid containing a 1,4,5,6-tetrahydropyrimidine ring (G. J. Shaw, R. D. Wilson, G. A. Lane, L. D. Kennedy, D. B. Scott, and G. J. Gainsford, J. Chem. Soc. Chem. Commun., p. 180-181, 1986), and the other, yellow-1, stains yellow with ninhydrin. Both compounds were degraded by R. loti NZP2037 but not by strains of Rhizobium meliloti, Rhizobium trifolii, or Agrobacterium tumefaciens. Under the conditions tested neither compound was able to serve as a sole source of C or N for growth of R. loti NZP2037. Rhizolotine and yellow-1 were found in nodules from a range of different legumes inoculated with NZP2037, suggesting that the Rhizobium and not the host plant determines their synthesis. Neither compound was found in nodulelike structures of L. pedunculatus induced by transposon Tn5-induced noninfectious (Inf-) mutants of NZP2037 or in similar structures induced by a transconjugant of NZP2037 containing the symbiotic (Sym) cointegrate plasmid pPN1 of R. trifolii. Both compounds were also absent in the ineffective nodules induced by the bacterial-release-negative (Bar-) mutant, strain PN239. However, both compounds were present in nodules induced by the fixation-negative (Fix-) mutant PN235 and in Fix+ nodules formed by a plasmid-cured derivative of NZP2037. These results would suggest that infection and bacterial release from the infection thread are necessary for nodule (symbiotic) synthesis of these compounds. PMID:3025173

Scott, D B; Wilson, R; Shaw, G J; Petit, A; Tempe, J

1987-01-01

 
 
 
 
261

Final Environmental Statement related to the operation of Wolf Creek Generating Station, Unit No. 1. Docket No. STN 50-482, Kansas Gas and Electric Company, et al  

International Nuclear Information System (INIS)

This final environmental statement contains the second assessment of the environmental impact associated with operation of Wolf Creek Generating Station Unit 1 pursuant to the National Environmental Policy Act of 1969 (NEPA) and 10 CFR Part 51, as amended, of the NRC's regulations. This statement examines: the affected environment, environmental consequences and mitigating actions, and environmental and economic benefits and costs. Land use and terrestrial- and aquatic-ecological impacts will be small. Air-quality impacts will also be small. However, steam fog from the station's cooling lake has the potential for reducing visibility over nearby roads and bridges. A fog-monitoring program for roads and bridges near the lake has been recommended. Impacts to historic and prehistoric sites will be negligible. Chemical discharges to the Neosho River are expected to have no appreciable impacts on water quality under normal conditions and will be required to meet conditions of the station's NPDES permit. The effects of routine operations, energy transmission, and periodic maintenance of rights-of-way and transmission line facilities should not jeopardize any populations of endangered or threatened species. No significant impacts are anticipated from normal operational releases of radioactivity. The risk associated with accidental radiation exposure is very low. The net socioeconomic effects of the project will be beneficial. The action called for is the issuance of an operating license for the Wolf Creek Generating Station Unit 1

1982-01-01

262

Basis for the Competitiveness of Rhizobium Japonicum in Nodulation of Soybean. Final Progress Report.  

Science.gov (United States)

This study sought to identify molecular, genetic and environmental factors most crucial to the ability of an inoculated strain of rhizobia to nodulate soybean roots in the face of competition from indigenous microorganisms. Co-inoculation of a more effici...

W. R. Evans W. D. Bauer

1986-01-01

263

Biochemical Analysis of Chickpea Protection Against Fusarium Wilt Afforded by Two Rhizobium Isolates  

Directory of Open Access Journals (Sweden)

Full Text Available Germinated seeds of two chickpea cultivars ILC482 and INRAT87/1, respectively susceptible and moderately resistant to Fusarium oxysporum f. sp. ciceris (Foc, were preinoculated with a suspension of two Rhizobium isolates PchDMS and Pch43. Three days later, the seedlings were challenged by root dip with a conidial suspension of Foc race 0. The two Rhizobium isolates protected chickpea plants from F. oxysporum infection; the best protection has been obtained by PchDMS for the two cultivars. For the susceptible cultivar, mortality was 12.5 and 33.33% for treated plants, respectively with PchDMS and Pch43 as compared to the 79.16% in the inoculated control with Foc only. For the INRAT87/1 Cv. mortality was 8.33 and 12.5% for treated plants, respectively with PchDMS and Pch43 compared to the 54.16% in the control inoculated treatment. The two Rhizobium isolates stimulated the peroxidases and polyphenoloxidases activities and induced the accumulation of phenolic compounds. The maximum of peroxidases activities in plant roots were reached 24 h after challenging. However, the higher activity of polyphenoloxidases and the higher level of the phenolic compounds were recorded 72 h after Foc inoculation. Comparing the two strains, PchDMS was more effective in inducing enzymes and phenolic compounds and highest levels were recorded in INRAT87/1 cultivar.

A. Arfaoui

2005-01-01

264

Genodiversity of dominant Rhizobium leguminosarum bv. Trifolii isolated from 11 types of soil in Serbia  

Directory of Open Access Journals (Sweden)

Full Text Available Rhizobium leguminosarum bv. trifolii is microsymbiont Trifolium pratense and Trifolium repens, which are very important legumes in Serbia. The natural nodulating population of those bacteria was collected and estimated biodiversity distribution by monitoring dominant genotypes of these bacteria. The population of Rhizobium leguminosarum bv. trifolii were collected from 50 marked locations of 11 types of soil in Serbia. 437 natural isolates, rescued from nodules of Trifolium repens or Trifolium pratense, were analyzed by phenotypic approach. We obtained 156 different isolates on the basis of differences in their IAR - intrinsic antibiotic resistance (five antibiotics and HMT- heavy methal tolerance (five heavy metals. We investigated 56 dominant isolates with more than three differences in IAR-HMT patterns by REP-PCR and RAPD fingerprinting (AP10 and SPH 1 primers. The results showed genodiversity of dominant Rhizobium leguminosarum bv. trifolii field isolates and offered the possibility to assess their changes on marked locations during time and under different environmental conditions and geographical distribution.

Joši? Dragana

2008-01-01

265

Cloning and DNA Sequence Analysis of the Haloalkanoic Permease Uptake Gene from Rhizobium sp. RC1  

Directory of Open Access Journals (Sweden)

Full Text Available The aims of the study were to clone and identify the putative haloacid permease gene in Rhizobium sp. RC1. The putative dehrP gene encoding an uptake protein in Rhizobium sp. RC1 was identified by DNA sequence analysis. An approximately 3.8 kb DNA sequence upstream of dehalogenase D (dehD in plasmid pSC1 was analyzed and revealed an open reading frame of 1239 kb which encoded for 412 amino acids with calculated subunit molecular weight of 45 kDa and isoelectric point of 9.78. The amino acid sequence of DehrP gave high sequence identity of 86% with putative monochloropropionic acid permease from Agrobacterium sp. NHG3 and 62% with haloacid-specific transporter from Burkholderia cepacia MBA4. Comparison of the predicted amino acid sequence with the CD server (www.ncbi.nlm.nih.gov NCBI database also revealed the putative DehrP contained signatures of sugar transport proteins of an integral membrane protein. Therefore, a new Rhizobial dehalogenase genetic organization was proposed. However, further characterization of this transporter protein is required to fully comprehend the dehalogenase uptake system of Rhizobium sp. RC1.

S. Hamdan

2010-01-01

266

Effects of Heavy Metal from Polluted Soils on the Rhizobium Diversity  

Directory of Open Access Journals (Sweden)

Full Text Available Heavy metals adversely influence microorganisms, affecting their growth, abundance, genetic diversity, nodulation ability and efficacy. The aim of this study was to isolate and characterize free-leaving Rhizobium from soil which were artificially polluted with Cu (100, 250, and 500 mg kg-1 soil, Zn (300, 700, and 1500 mg kg-1 soil and Pb (50, 250, and 1000 mg kg-1 soil, but also with a mixture of all these metals, and cultivated with red clover (Trifolium pratense L., and to compare them with bacteria isolated from similar type of soil, but unpolluted. Rhizobia from soil were isolated on YMA medium with or without bromothymol blue (0.00125% as a pH-change indicator and the morpho-physiological characteristics of the colonies were examined. The number of Rhizobium was estimated using the most probable number method. Compared to the control, a decrease of rhizobia number and an increase of the metal concentration were observed. Several decameric primers (Operon Technology type were used and a reduced polymorphism among isolated bacteria was observed. Moreover, significant differences were observed among these strains and the collection strains used as reference. Also, when primers nodCF/nodCI for detection of nod genes were used, several amplicons were obtained, different from the results obtained with similar strains isolated from unpolluted soil. These results suggest that the survival „price” of the Rhizobium in such polluted area was the alteration of some genes, including those involved in symbiosis and, probably, in nitrogen fixation.

Georgiana PLOPEANU

2011-05-01

267

Effects of nano-TiO? on the agronomically-relevant Rhizobium-legume symbiosis.  

Science.gov (United States)

The impact of nano-TiO? on Rhizobium-legume symbiosis was studied using garden peas and the compatible bacterial partner Rhizobium leguminosarum bv. viciae 3841. Exposure to nano-TiO? did not affect the germination of peas grown aseptically, nor did it impact the gross root structure. However, nano-TiO? exposure did impact plant development by decreasing the number of secondary lateral roots. Cultured R. leguminosarum bv. viciae 3841 was also impacted by exposure to nano-TiO?, resulting in morphological changes to the bacterial cells. Moreover, the interaction between these two organisms was disrupted by nano-TiO? exposure, such that root nodule development and the subsequent onset of nitrogen fixation were delayed. Further, the polysaccharide composition of the walls of infected cells of nodules was altered, suggesting that the exposure induced a systemic response in host plants. Therefore, nano-TiO? contamination in the environment is potentially hazardous to the Rhizobium-legume symbiosis system. PMID:23933452

Fan, Ruimei; Huang, Yu Chu; Grusak, Michael A; Huang, C P; Sherrier, D Janine

2014-01-01

268

Phylogeny of the Rhizobium-Allorhizobium-Agrobacterium clade supports the delineation of Neorhizobium gen. nov.  

Science.gov (United States)

The genera Agrobacterium, Allorhizobium, and Rhizobium belong to the family Rhizobiaceae. However, the placement of a phytopathogenic group of bacteria, the genus Agrobacterium, among the nitrogen-fixing bacteria and the unclear position of Rhizobium galegae have caused controversy in previous taxonomic studies. To resolve uncertainties in the taxonomy and nomenclature within this family, the phylogenetic relationships of generic members of Rhizobiaceae were studied, but with particular emphasis on the taxa included in Agrobacterium and the "R. galegae complex" (R. galegae and related taxa), using multilocus sequence analysis (MLSA) of six protein-coding housekeeping genes among 114 rhizobial and agrobacterial taxa. The results showed that R. galegae, R. vignae, R. huautlense, and R. alkalisoli formed a separate clade that clearly represented a new genus, for which the name Neorhizobium is proposed. Agrobacterium was shown to represent a separate cluster of mainly pathogenic taxa of the family Rhizobiaceae. A. vitis grouped with Allorhizobium, distinct from Agrobacterium, and should be reclassified as Allorhizobium vitis, whereas Rhizobium rhizogenes was considered to be the proper name for former Agrobacterium rhizogenes. This phylogenetic study further indicated that the taxonomic status of several taxa could be resolved by the creation of more novel genera. PMID:24581678

Mousavi, Seyed Abdollah; Österman, Janina; Wahlberg, Niklas; Nesme, Xavier; Lavire, Céline; Vial, Ludovic; Paulin, Lars; de Lajudie, Philippe; Lindström, Kristina

2014-05-01

269

Coexistence of Burkholderia, Cupriavidus, and Rhizobium sp. nodule bacteria on two Mimosa spp. in Costa Rica.  

Science.gov (United States)

rRNA gene sequencing and PCR assays indicated that 215 isolates of root nodule bacteria from two Mimosa species at three sites in Costa Rica belonged to the genera Burkholderia, Cupriavidus, and Rhizobium. This is the first report of Cupriavidus sp. nodule symbionts for Mimosa populations within their native geographic range in the neotropics. Burkholderia spp. predominated among samples from Mimosa pigra (86% of isolates), while there was a more even distribution of Cupriavidus, Burkholderia, and Rhizobium spp. on Mimosa pudica (38, 37, and 25% of isolates, respectively). All Cupriavidus and Burkholderia genotypes tested formed root nodules and fixed nitrogen on both M. pigra and M. pudica, and sequencing of rRNA genes in strains reisolated from nodules verified identity with inoculant strains. Inoculation tests further indicated that both Cupriavidus and Burkholderia spp. resulted in significantly higher plant growth and nodule nitrogenase activity (as measured by acetylene reduction assays) relative to plant performance with strains of Rhizobium. Given the prevalence of Burkholderia and Cupriavidus spp. on these Mimosa legumes and the widespread distribution of these plants both within and outside the neotropics, it is likely that both beta-proteobacterial genera are more ubiquitous as root nodule symbionts than previously believed. PMID:16461667

Barrett, Craig F; Parker, Matthew A

2006-02-01

270

Mathématiques, Mind et Geist.  

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Full Text Available L’article est une exploration systématique de la dualité des figures du Mind et du Geist, le premier étant entendu comme l’esprit en tant que partie de la nature scientifiquement objectivable, le second comme l’esprit en tant qu’acteur immatériel insaisissable de la pensée. De plus, cette dualité est étudiée du point de vue de l’interférence de la mathématique avec elle, dans plusieurs contextes. Sont ainsi successivement analysés : le conflit entre les deux « modèles » du Mind, le computationnaliste et le dynamiciste; la définition philosophique et la définition épistémologique du Geist ; le jeu entre Mind et Geist dans les recherches cognitives contemporaines ; l’ambivalence de la logique et des mathématiques vis-à-vis de l’opposition Mind/Geist. Dans la partie finale, on propose une définition personnelle du Geist–en termes d’adresse et de sujet–dont dérive une détermination du Mind. Revenant sur ces nouvelles bases à l’interférence avec la mathématique, on conclut sur la question essentielle et délicate de la paramétrisation de la conscience.This paper systematically investigates the conflicting figures of Mind and Geist : Mind has to be understood as some part of nature likely to become the object of science, while Geist names the unmaterial unseizable protagonist of thought. Further, the opposition of the two figures is studied in the light of the way mathematics interfere with it, in several contexts. This leads to following analyses : how computational and dynamicist models of Mind compete within cognitive science; how Geist may be defined philosophically and epistemologically ; how Mind and Geist differently come to be considered or to be aimed at within contemporary cognitive research ; how mathematics and logic play an ambivalent part with respect to the Mind/Geist opposition. In the final section of the paper, a personal definition of the Geist–in terms of address and subject–is proposed, which also leads to some conceptual determination of the Mind. Coming back to the interference with mathematics on this new basis, the paper concludes by an examination of the difficult question of the parametrization of consciousness.

Jean-Michel Salanskis

2004-04-01

271

Effect of Rhizobium sp., on Growth of Pathogenic Fungi under in vitro Conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In a laboratory study chickpea root nodulating bacterium Rhizobium sp., strain Thal-8 significantly inhibited the growth of pathogenic fungi (Alternaria alternata, Fusarium sp. Ascochyta rabiei, Drechslera sp. and Curvularia sp.) in potato dextrose agar media. The inhibition rate displayed differences in accordance with different fungi cultures. However, the inhibitory effect of Rhizobium sp., strain Thal-8 occurred most on pure cultures growth...

Tabassam Sharif; Samina Khalil; Shahbaz Ahmad

2003-01-01

272

Genetics and Biochemistry of the Rhizobium Meliloti Acidic Extracellular Heteropolysaccharide and Its Role in Nodulation: Annual Report for the Period 1 June 1987-31 May 1988.  

Science.gov (United States)

The symbiotic association of Rhizobium with legumes results in a vital supply of inexpensive nitrogen for the growth of crops such as soybean and alfalfa. In a complex series of events, the bacterial symbiont, Rhizobium, induces the formation of a special...

J. A. Leigh

1988-01-01

273

Implementation and validation of the linear collider final focus prototype: ATF2 at KEK (Japan); Implementation et validation de la focalisation finale du collisionneur lineaire: ATF2 at KEK (Japan)  

Energy Technology Data Exchange (ETDEWEB)

The two linear collider projects (ILC and CLIC) require beam delivery systems with the same local chromaticity correction scheme in the final focus. ATF2 at KEK (Japan), an implementation of this scheme scaled down in energy, uses the beam extracted from ATF, which is one of the most successful damping rings in the world. The ATF2 goals are to prove the feasibility and the stability of the linear collider final focus system and to define and test the experimental correction procedures. The nominal beam sizes at the interaction point are 3 {mu}m horizontally and 37 nm vertically. The work in this thesis was started before the commissioning and covered its first year at KEK. At the beginning, we observed that the stripline BPMs were not working properly so we investigated their behavior in detail. The problem was characterized and later solved in 2010 by upgrading the electronics. We then developed an efficient procedure to check the modeling of the beam line, comparing measurements of transfer matrices to model predictions calculated on line. After obtaining a good agreement, we were able to successfully test the trajectory correction algorithm which had been developed, reducing the difference between BPM measurements and the target values down to 0.5 mm horizontally and 0.2 mm vertically. We also successfully developed an algorithm to reconstruct pulse to pulse beam trajectory fluctuations with sub-micron precision. This reconstruction also gave a precise determination of the energy fluctuation, allowing a global fit of the dispersion function along the beam line with a precision of a few mm. A simple and robust IP beam size tuning method using sextupoles displacements was also studied in simulation, whose performance indicates that, given some assumptions on the error level of the beam, convergence within 20% of the nominal beam size should be possible in 8 hours with a 80% probability. (author)

Renier, Y.

2010-06-15

274

Comparative effectiveness of different Rhizobium sp. for improving growth and yield of maize (Zea mays L.  

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Full Text Available During the last couple of decades, it has been demonstrated that rhizobia can associate with roots of non-legumes also without forming true nodules, and can promote their growth by using one or more of the direct or indirect mechanisms of actions. This work examines the growth and yield responses of maize to inoculation with different species of rhizobia, isolated from the root nodules of chickpea (Cicer arietinum L., lentil (Lens culinaris M. and mung bean (Vigna radiata L. in pots and fields. Twenty isolates of rhizobia were isolated from root nodules each of mung bean, lentil and chickpea and were screened under axenic conditions. On the basis of their promising performance under axenic conditions, nine most efficient isolates (three from each legume host were selected, characterized and further evaluated for their growth promoting activities by conducting pot and field experiments. Results of pot experiment revealed that maximum increase in grain yield, 1000 grain weight, N, P and K uptake (up to 47.89, 54.52, 73.46, 84.66 and 59.19% by CRI28, respectively, over un-inoculated control was produced by the isolate of Mesorhizobium ciceri. Whereas, maximum improvement in rest of the parameters was caused by the isolates of Rhizobium phaseoli (i.e. fresh biomass, straw yield and root length up to 36.30% by A18, 25.46% by S6 and 81.89% by A18, respectively over un-inoculated control. Rhizobium leguminosarum isolates came out to be the least effective among the species tested. Similarly, all the selected isolates improved the growth and yield attributing parameters in fields as well but with varying capacity compared with un-inoculated control. The selected isolates of Mesorhizobium ciceri and Rhizobium phaseoli again remained superior compared to the isolates of Rhizobium leguminosarum under field conditions. The results of this study imply that rhizobium species had potential to promote growth and yield of maize but this technology should be employed after appropriate site specific investigations of particular rhizobial specie with respect to specific non-leguminous crop variety to get maximum benefit in terms of better growth and yield.

Ijaz Mehboob, Zahir Ahmad Zahir, Muhammad Arshad, Muhammad Khalid

2012-05-01

275

Colonization and Nitrogenase Activity of Triticum aestivum (cv. Baccross and Mahdavi to the Dual Inoculation with Azospirillum brasilense and Rhizobium meliloti plus 2,4-D  

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Full Text Available The potential enhancement of root colonization and nitrogenase activity of wheat cultivars (Baccross and Mahdavi was studied with application of two Azospirillum brasilense strains (native and Sp7 co-inoculated with two Rhizobium meliloti strains (native and DSMZ 30135. The results indicated that the colonization was different due to the strains and cultivars of wheat were used. Native A. brasilense colonized wheat root better than Sp7 strain. However, Baccross cv. reacted better with native Azospirillum compared to Mahdavi cv. which reacted better with Sp7. When plants inoculated with dual inoculants (SP7 with standard Rhizobium, the colonization of Azospirillum were increased significantly (from 1.67x105 to 22x105 cfu g-1 FW for Baccras cv. and 3.67x105 to 26x105 cfu g-1 FW for Mahdavi cultivar. When the standard Rhizobium as co-inoculants changed to the native Rhizobium, the colonization of Azospirillum was higher when compared to the single inoculants but was almost the same when compared to the standard Rhizobium. When the standard or native strains of Rhizobium used as single inoculation of wheat roots, the number of Rhizobium in the wheat roots were not changed significantly. However, when plants co-inoculated with Rhizobium and Azospirillum, the colonization of Rhizobium was increased. Co-inoculation of standard strain of R. melilot with A. brasilense Sp7 showed that the colonization of Rhizobium were increased from 0.67x105 to 21x105 cfu g-1 FW for Baccross cv. and 0.33x105 to 18x105 cfu g-1 FW for Mahdavi cv. This behavior was the same when inoculation of Rhizobium was happened with the native one. In dual inoculation, the highest nitrogenase activity was measured in combination of the local strains (native A. brasilense with the native R. meliloti and the lower one belongs to the combination of standard strains (Sp7 with standard R. meliloti. The difference in nirtogenase activity for different cultivars of wheat with Sp7 and standard Rhizobium is not significant but the difference for Sp7 strain plus native Rhizobium is significant (p>0.05. However, the differences were not significant (p<0.05 for nitrogenase activity in bacterial tubes, the difference for nitrogenase activity of co-inoculated plants with combination of Sp7 and Rhizobium either standard or native were significantly different

Askary Mehry

2008-01-01

276

Gérer et alerter  

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Full Text Available Sur la base de deux événements d’inondation ayant touché récemment, dans des contextes politiques, organisationnels et hydrologiques bien différents, de nouveaux quartiers d’habitation, cet article rend compte des pratiques des acteurs impliqués dans des situations d’alerte et de crise en Suisse. Le recensement des acteurs – à travers leur rôle et leur place dans les mécanismes de préparation, d’alerte et de gestion –, ainsi que l’inventaire des documents mobilisés par ceux-ci, ont été réalisés dans les deux cas. Cette analyse a permis d’évaluer la gestion des événements, de déceler les changements organisationnels qui ont suivi les crises et de connaître la conception et le degré de formalisation du risque dont étaient dotés les différents acteurs avant et après les inondations. Plus encore, l’analyse a documenté les nouveaux processus d’alerte et de prévision qui ont été mis en place suite aux événements. Il s’avère ainsi que les épisodes d’inondation agissent de façon décisive sur la production de connaissances, à un degré variable selon les acteurs. Ces épisodes révèlent aussi parfois l’existence de connaissances « en attente » qui ne sont pas encore intégrées dans les procédures institutionnelles. Tant du point de vue de la prévision que de la gestion de la crise, ils permettent aussi de tester les canaux de l’information et de combler les déficits d’organisation, de collaboration et de sécurisation des dispositifs de communication. En outre, les risques et les crises liés aux inondations modifient les dynamiques et les politiques territoriales, conséquences du réajustement des réseaux d’acteurs. La mise en place de dispositifs d’intervention et de gestion de crise se montre cependant plus efficace que la refonte des dispositifs d’aménagement, généralement longue. Toutefois, la mémoire des événements se dégradant avec le temps, une inscription territoriale du risque s’avère nécessaire.Based on two flood events that recently affected new housing areas in very different political, organisational and hydrological contexts, this article examines the practices of actors involved in emergency and crisis situations in Switzerland. In both cases, the actors are identified – through their role and their position in the various procedures related to crisis management – and an inventory is made of the documents used. The study examines how the flood events were managed, identifies the organisational changes that followed the crises, and determines how the risk was conceived and to what extent it was formalised by the different actors both before and after the floods. Finally new forecasting and warning procedures that were set up following the events are described. The study shows that floods have a decisive impact on the production of knowledge, but that this phenomenon varies according to the actors. Events such as floods also sometimes reveal the existence of "latent" knowledge, or knowledge that is available but has not yet been integrated into institutional procedures. In terms of both forecasting and crisis management, these events also provide the opportunity to test information channels and to identify and correct any problems relating to organisation, cooperation or the reliability of means of communication. Among other things, the risks and crises related to flooding modify the dynamics and policies of the local area as a result of readjustments in the networks of actors. The introduction of emergency and crisis management measures appears more effective, however, than the reorganisation of planning and development procedures, a process which generally takes a lot longer. Nevertheless, since the recollection of events tends to fade with time, it is important that risks find a more concrete form of spatial expression on the landscape.

Valérie November

2009-03-01

277

Evaluation of Bean (Phaseolus vulgaris Seeds Inoculation with Rhizobium phaseoli and Plant Growth Promoting Rhizobacteria on Yield and Yield Components  

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Full Text Available To study the effect of co-inoculation with plant growth-promoting rhizobacteria (PGPR and Rhizobium, on yield and yield components of common bean (Phaseolus vulgaris L. cultivars was investigated in 2 consecutive years under field condition of plant growing evidence indicates that soil beneficial bacteria can positively affect symbiotic performance of rhizobia. PGPR strains Pseudomonas fluorescens P-93 and Azospirillum lipoferum S-21 as well as two highly effective Rhizobium strains were used in this study. Common bean seeds of three cultivars were inoculated with Rhizobium singly or in a combination with PGPR to evaluate their effect on growth characters. A significant variation of plant growth in response to inoculation with Rhizobium strains was observed. Treatment with PGPR significantly increased pod per plant, number of seeds per pod, weight of 100 seed, weight of seeds per plant, weight of pods per plant, total dry matter in R6 as well as seed yield and protein content. Co-inoculation with Rhizobium and PGPR demonstrated a significant increase in the yield and yield components. The results showed that all treatments of bacteria increased yield; however, strains Rb-133 with Pseudomonas fluorescens P-93 gave the highest seed yield, number of pods per plant, weight of 100 seed, seed protein yield, number seed per pod, seed protein yield.

M. Yadegari

2008-01-01

278

Use of combined inoculum of Azospirillum and Rhizobium in winged bean Psophocarpus tetragonolobus (L D.C  

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Full Text Available The potential of using the free living N -fixing Azospirillum in increasing the nodulation and N2-fixation by Rhizobium in winged bean was analysed. Various strains of winged bean Rhizobium and several strains of Azospirillum were tested in combined inoculations. Substantial increases in nodulation, N2-fixation, shoot dry matter production and N gain due to the mixed inoculation were obtained in one Rhizobium strain namely KUL-BH and most of the Azospirillum strains used. The influence of Rhizobium genotype in expressing the association effect was more decisive than that of Azospirillum. The cell-free extract of Azospirillum produced the same enhancement effect as that of the organism itself, while the culture supernatant also showed the same in some instances. Since the response to combined inoculation in winged bean was obtained only with one strain of Rhizobium, the factors that could influence the nodulation enhancement were investigated in detail. An attempt was made in finding out the possible mechanism involved in the enhancement effect by Azospirillum.

Iruthayathas, EE.

1985-01-01

279

Effect of Rhizobium japonicum Inoculum Doses (Liquid Culture on the Growth and Seed Yield of Soybean Crop  

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Full Text Available The field experiments were conducted during 2000 at Tandojam, Pakistan to evaluate the effect of Rhizobium japonicum inoculum doses of liquid culture on the growth and seed yield of soybean crop. One liter liquid culture medium was prepared by standard procedure by adding 0.5g K2HPO4, 0.2g MgSO4, 0.1g NaCl, 0.05g yeast extract, 10.0g Minitol, and 1000ml distilled water. Six Rhizobium japonicum doses (10, 15, 20, 25, 30 ml, and untreated control were laid-down in Randomized Complete Block Design. The adequate level of 25 ml with 300 grams sand maize as seed treatment inoculant was found more effective for maximum growth and seed yield as compared to higher and lower doses of Rhizobium japonicum. Thus, it was concluded that Rhizobium japonicum exhibited the positive change in terms of enhanced growth and seed yield. The satisfactory results would be achieved if, the soybean seed will be treated with 25 ml of Rhizobium japonicum inoculum.

F. C. Oad

2002-01-01

280

Yield Performance of Mungbean (Vigna radiata L. Wilczek cv. Barimung-4 as Influenced by Rhizobium Inoculation and NPK Fertilizers  

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Full Text Available A field experiment was conducted at the Regional Agricultural Research Station of Barisal, Bangladesh during the Kharif season of the year 2000 to find the optimum fertilizer rate for summer mungbean cv. Barimung-4 in an attempt to maximize the yield potential. In this regard, various combinations of NPK fertilizers and Rhizobium inoculation (N20P40K20 kg ha?1, P40K20 kg ha?1, N20K20 kg ha?1, N20P40 kg ha?1, N20 kg ha???1, Rhizobium + P40K20 kg ha?1, Rhizobium, and control were imposed to the experimental plots. Results revealed that Barimung-4 produced the maximum seed (1270.21 kg ha?1 and straw yields (2434.36 kg ha?1 when the crop was fertilized with N20P40K20 kg ha?1 followed by Rhizobium + P40K20 kg ha?1 (1220.30 and 2406.14 kg ha?1, respectively. The lowest seed and straw yields were obtained from the control (887.01 and 1864.68 kg ha?1, respectively. Different plant characteristics such as plant height, branches/plant, pods/plant, pod length, seeds/pod, 1000-seed weight and harvest index increased significantly due to the application of various combinations of NPK fertilizers and Rhizobium inoculation over the control.

M.A. Rahman

2002-01-01

 
 
 
 
281

Synergism of VAM and Rhizobium on production and metabolism of IAA in roots and root nodules of Vigna mungo.  

Science.gov (United States)

Mature and healthy root nodules of Vigna mungo appeared to contain higher amount of indole-acetic acid (IAA) than non-nodulated roots. Dual effect of VAM fungus, Glomus fasciculatum and the nitrogen-fixing bacteria, Rhizobium sp. on the nodulation of roots of V. mungo was studied. It was recorded that the roots which were inoculated simultaneously with both the symbionts i.e., G. fasciculatum and Rhizobium exhibited greater amount of IAA production than the non-inoculated roots. A tryptophan pool present in the mature nodules and young leaves might serve as a precursor for IAA production in the roots and in the nodules. Activity of IAA-metabolizing enzymes, such as IAA oxidase, peroxidase, and polyphenol oxidase was investigated which indicates the active metabolism of IAA in roots and nodules. The Rhizobium symbiont isolated from fresh nodules of V. mungo produced significant amount of IAA under in vitro condition when tryptophan was added to the medium as precursor. Present study represents some beneficial effects of Rhizobium and G. fasciculatum on the production and metabolism of IAA in roots and nodules of V. mungo. The important physiological implication of the study on IAA production and its metabolism in Rhizobium-Legume-VAM tripartite symbiosis is certainly representing a new approach to satisfy the hormonal balance in the host plant. PMID:20306316

Chakrabarti, Jayanta; Chatterjee, Sabyasachi; Ghosh, Sisir; Chatterjee, Narayan Chandra; Dutta, Sikha

2010-09-01

282

Bouvard et Pécuchet et le savoir médical  

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Full Text Available Le présent article a pour objet le dossier médical que Flaubert a constitué pour la préparation du chapitre III de Bouvard et Pécuchet. Ce dossier considérable, qui contient des notes de lecture prises par le romancier en vue de la rédaction du chapitre médical, nous permet de comprendre à quel point le « comique d’idées » propre au roman encyclopédique est le produit d’un travail intense sur le savoir. L’écriture romanesque de Bouvard explore en effet les configurations épistémologiques de chaque discipline, et met au jour surtout ses apories et ses insuffisances. Nous nous proposons donc d’aborder le dossier médical pour saisir le sens de l’excès documentaire pour l’esthétique flaubertienne. Notre étude se compose de trois parties. D’abord, nous étudierons la composition du dossier en nous demandant quels ouvrages médicaux a lu l’auteur de Bouvard. Ensuite, nous essaierons d’examiner le travail critique de Flaubert pratiqué sur les discours du savoir, en particulier la manière dont il traque et construit des contradictions. Enfin, nous analyserons un épisode du roman, celui de la fièvre typhoïde de Gouy, dont l’étude de la genèse nous montrera l’inscription de l’épistémologique dans la représentation romanesque.This article proposes to study the medical documents gathered by Flaubert for the preparation of Chapter III of Bouvart et Pécuchet. This substantial file, which contains reading notes taken by the novelist for the writing of the medical chapter, allows us to understand to what extent the “comic of ideas”, characteristic of the encyclopedic novel, is the result of an intensive work on knowledge. Indeed, the novelistic writing of Bouvard explores the epistemological configurations of each discipline, and in particular reveals its aporia and its insufficiencies. We have chosen to focus on the medical file in order to understand the meaning of the documentary excess with respect toFlaubert’s esthetics. First we shall study the components of the file, identifying the medical works read by the author of Bouvard. Then we will examine Flaubert’s critical reflection on knowledge, in particular the way he hunts down and constructs contradictions. Finally, we will analyze an episode in the novel, that of Gouy’s typhoid fever. We shall study its genesis which will show the presence of the epistemological in the art of the novel.

Norioki Sugaya

2009-01-01

283

Effect of Rhizobial Management upon Rhizobial Population, Nodulation and Growth of Yard Long Beans (Vigna sesquipedalis L. A New Approach to Maximize Benefits from Rhizobium  

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Full Text Available The work aimed to investigate some benefits derived from Rhizobium technology. The results showed that management methods in retaining native Rhizobium being tested had a tremendous effect on population management, i.e. native Rhizobium could be maintained. However, Rhizobium has preferential level of selectivity to host. KKU 25 yard long bean plants had the highest level of rhizobia population followed by white seeded cultivar at day 30 and thereafter the amount of rhizobia population declined with time in all subplots whilst no population was detected from the control subplots. Native Rhizobium had significant potentiality for growth of yard long bean crop plants by supplying some certain amount of nitrogen being fixed from the atmosphere and the growth of yard long bean crop plants was similar to that of the control subplots that received nitrogen from chemical nitrogen fertilizer.

W. Sinsiri

2002-01-01

284

Diversity of Rhizobium-Phaseolus vulgaris symbiosis: Overview and perspectives  

International Nuclear Information System (INIS)

Common bean (Phaseolus vulgaris) has become a cosmopolitan crop, but was originally domesticated in the Americas and has been grown in Latin America for several thousand years. Consequently an enormous diversity of bean nodulating bacteria have developed and in the centers of origin the predominant species in bean nodules is R. etli. In some areas of Latin America, inoculation, which normally promotes nodulation and nitrogen fixation is hampered by the prevalence of native strains. Many other species in addition to R. etli have been found in bean nodules in regions where bean has been introduced. Some of these species such as R. leguminosarum bv. phaseoli, R. gallicum bv. phaseoli and R. giardinii bv. phaseoli might have arisen by acquiring the phaseoli plasmid from R. etli. Others, like R. trap id, are well adapted to acid soils and high temperatures and are good inoculants for bean under these conditions. The large number of rhizobia species capable of nodulating bean supports that bean is a promiscuous host and a diversity of bean-rhizobia interactions exists. Large ranges of dinitrogen fixing capabilities have been documented among bean cultivars and commercial beans have the lowest values among legume crops. Knowledge on bean symbiosis is still incipient but could help to improve bean biological nitrogen fixation. (author)

2001-03-13

285

STUDY OF INTERACTIVE EFFECT OF RHIZOBIUM, AZOTOBACTER AND TRICHODERMA ALONE AND IN COMBINATION ON TRIGONELLA FOENUM-GRACEUM L  

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Full Text Available Trigonella foenum-graceum L. has unique ability to maintain a high protein level throughout the growing season therefore it is cultivated as a commercial crop. The use of biofertilizers on Trigonella plant showed the significant effect on growth and leaf, seed protein content. Compared to control shoot length and root length was more in the pot containing different biofertilizers. The total Chlorophyll content was maximum in the leaves of plants grown in the pot containing 50 gm of Rhizobium and 50 gm Azotobacter. The maximum leaf protein content was noticed in the plant grown in the pot containing 50 gm of Rhizobium and 50 gram of Azotobacter. The maximum seed protein was noticed in the plants grown in soil containing 50 gm of Rhizobium and 50 gm of Azotobacter.

PATIL VILAS ARJUN

2013-01-01

286

Influence of a carbamate pesticide on growth, respiration (14C)-carbon metabolism and symbiosis of a Rhizobium sp  

International Nuclear Information System (INIS)

Addition of aldicarb (2 methyl-2(methyl thio) propionaldehyde-O-methyl carbamoyl oxime) in the growth medium enhanced the growth of Rhizobium sp. (cowpea group) at 2ppm level while an inhibition was observed at the normal (5 ppm) and higher (10 ppm) concentrations. Respiration of the cells was also inhibited by 5 and 10 ppm levels of the chemical eventhough a stimulation was observed at 2 ppm (lower) concentration. The insecticide, when incorporated at 5 and 10 ppm levels in the medium increased the 14C-glucose incorporation and considerably altered the assimilation of the radioactive carbon in different fractions of rhizobium cells. Soil application of this insecticide (Temik 10 G) reduced the number of nodules formed and the total nitrogen content in cowpea plants inoculated with the Rhizobium sp. but enhanced the dry matter production of cowpea plants. (Auth.)

1979-01-01

287

Effect of Rhizobium inoculation on some characters of a high protein mutant and its parent field bean Vicia faba L  

International Nuclear Information System (INIS)

M1011 is a high protein mutant originally selected from the Egyptian bean (Vicia faba L.) variety Giza2 (G2) after seven generations of treating seeds with 4kR of "6"0Co gamma rays. Both the mutant line M1011 and its parent variety G2 were planted in soil inoculated with Rhizobium phaseoli after being sterilized. The plant and yield characters of both were then investigated. Results showed that the mean values of plant height, total and fertile number of branches per plant, number of pods per plant, seed yield and seed protein content increased significantly in both M1011 and G2 due to pre-sowing Rhizobium inoculation. Significant earliness in flowering and an increase in the number of seeds per pod were also noticed in M1011 after Rhizobium treatment. Therefore, the mutant line showed higher efficiency in utilizing bacterially fixed nitrogen than its parent mother variety Giza2. (author)

1981-03-13

288

“STUDY OF INTERACTIVE EFFECT OF RHIZOBIUM, AZOTOBACTER AND TRICHODERMA ALONE AND IN COMBINATION ON TRIGONELLA FOENUM-GRACEUM L.”  

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Full Text Available Trigonella foenum-graceum L. has unique ability to maintain a high protein level throughout the growing season therefore it is cultivated as a commercial crop. The use of biofertilizers on Trigonella plant showed the significant effect on growth and leaf, seed protein content. Compared to control shoot length and root length was more in the pot containing different biofertilizers. The total Chlorophyll content was maximum in the leaves of plants grown in the pot containing 50 gm of Rhizobium and 50 gm Azotobacter. The maximum leaf protein content was noticed in the plant grown in the pot containing 50 gm of Rhizobium and 50 gram of Azotobacter. The maximum seed protein was noticed in the plants grown in soil containing 50 gm of Rhizobium and 50 gm of Azotobacter.

PATIL V. A.

2013-04-01

289

ETS marketing  

Energy Technology Data Exchange (ETDEWEB)

The author discusses how consumer-side electric thermal storage is a viable load management option for winter packing utilities. ETS loads do remove the demands of electric space heating and water heating from utility peaks without loss of kWh sales, and without promoting the competition. They can provide a flexible means of valley filling to improve load factors. They are capable of supplying 24 hours of residential space heating and water heating needs operated on an eight-hour charge control strategy, and without requiring adjustments in consumer lifestyles. They can be as efficient as other forms of electric heat and water heating and can provide an affordable option to consumers if the proper rate is applied.

Zehringer, V.

1987-01-01

290

Symbiotic effectiveness and ecological characterization of indigenous Rhizobium loti populations in Uruguay / Eficiência simbiótica e caracterização ecológica de uma população nativa de Rhizobium loti no Uruguai  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Os objetivos deste trabalho foram descrever a distribuição, densidade e variação sazonal de populações nativas de Rhizobium loti em diferentes solos uruguaios, e determinar a eficiência simbiótica e os fatores de tolerância a estresse de diversos isolados, tendo em vista a obtenção de cepas a serem [...] reintroduzidas como inoculantes em pastagens de Lotus. Rhizobium loti estava presente em dez solos estudados, e suas densidades variavam de ano para ano e em cada solo. Todos os isolados nodularam efetivamente o Lotus corniculatus. Os nódulos no Lotus pedunculatus e no Lotus subbiflorus eram pequenos, vermelhos na superfície, e ineficazes na fixação de N. O estudo de 50 isolados dos dez solos mostraram alta variabilidade na sua eficiência simbiótica, e alta tolerância ao pH. A população nativa era tolerante à acidez em meio de cultura (pH 4,5); 83% dela pode crescer em pH 4,5 em três dias. O presente trabalho mostrou que há grande diversidade entre as cepas de R. loti isoladas de solos uruguaios, e acentua a importância de se selecionar entre elas as mais eficientes e resistentes, para serem incluídas como inoculantes. Abstract in english The objectives of this work were to describe the distribution, density and seasonal variation of the indigenous populations of Rhizobium loti in different Uruguayan soils and to determine the symbiotic effectiveness and stress tolerance factors of different isolates, both with the aim of obtaining s [...] elected strains to re-introduce as inoculants in Lotus pastures. R. loti was present in ten soils studied and their densities varied from year to year and within each soil. All the isolates nodulated Lotus corniculatus effectively. The nodules in Lotus pedunculatus and Lotus subbiflorus were small, red on the surface and ineffective in nitrogen fixation. The study of 50 isolates from the ten soils showed high variability in their symbiotic efficiency and tolerance to pH. The indigenous population was acid tolerant in culture medium (pH 4.5), 83% of them could grow at pH 4.5 in 3 days. This work showed that there was a great diversity between the strains of R. loti isolated from Uruguayan soils and supports the importance of selecting among them the most efficient and resistant strains to be included in the inoculants.

Amalia, Baraibar; Llillian, Frioni; Maria Elena, Guedes; Hans, Ljunggren.

291

Symbiotic effectiveness and ecological characterization of indigenous Rhizobium loti populations in Uruguay Eficiência simbiótica e caracterização ecológica de uma população nativa de Rhizobium loti no Uruguai  

Directory of Open Access Journals (Sweden)

Full Text Available The objectives of this work were to describe the distribution, density and seasonal variation of the indigenous populations of Rhizobium loti in different Uruguayan soils and to determine the symbiotic effectiveness and stress tolerance factors of different isolates, both with the aim of obtaining selected strains to re-introduce as inoculants in Lotus pastures. R. loti was present in ten soils studied and their densities varied from year to year and within each soil. All the isolates nodulated Lotus corniculatus effectively. The nodules in Lotus pedunculatus and Lotus subbiflorus were small, red on the surface and ineffective in nitrogen fixation. The study of 50 isolates from the ten soils showed high variability in their symbiotic efficiency and tolerance to pH. The indigenous population was acid tolerant in culture medium (pH 4.5, 83% of them could grow at pH 4.5 in 3 days. This work showed that there was a great diversity between the strains of R. loti isolated from Uruguayan soils and supports the importance of selecting among them the most efficient and resistant strains to be included in the inoculants.Os objetivos deste trabalho foram descrever a distribuição, densidade e variação sazonal de populações nativas de Rhizobium loti em diferentes solos uruguaios, e determinar a eficiência simbiótica e os fatores de tolerância a estresse de diversos isolados, tendo em vista a obtenção de cepas a serem reintroduzidas como inoculantes em pastagens de Lotus. Rhizobium loti estava presente em dez solos estudados, e suas densidades variavam de ano para ano e em cada solo. Todos os isolados nodularam efetivamente o Lotus corniculatus. Os nódulos no Lotus pedunculatus e no Lotus subbiflorus eram pequenos, vermelhos na superfície, e ineficazes na fixação de N. O estudo de 50 isolados dos dez solos mostraram alta variabilidade na sua eficiência simbiótica, e alta tolerância ao pH. A população nativa era tolerante à acidez em meio de cultura (pH 4,5; 83% dela pode crescer em pH 4,5 em três dias. O presente trabalho mostrou que há grande diversidade entre as cepas de R. loti isoladas de solos uruguaios, e acentua a importância de se selecionar entre elas as mais eficientes e resistentes, para serem incluídas como inoculantes.

Amalia Baraibar

1999-06-01

292

Identification and Characterization of the Rhizobium sp. Strain GIN611 Glycoside Oxidoreductase Resulting in the Deglycosylation of Ginsenosides  

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Using enrichment culture, Rhizobium sp. strain GIN611 was isolated as having activity for deglycosylation of a ginsenoside, compound K (CK). The purified heterodimeric protein complex from Rhizobium sp. GIN611 consisted of two subunits with molecular masses of 63.5 kDa and 17.5 kDa. In the genome, the coding sequence for the small subunit was located right after the sequence for the large subunit, with one nucleotide overlapping. The large subunit showed CK oxidation activity, and the deglyco...

Kim, Eun-mi; Kim, Juhan; Seo, Joo-hyun; Park, Jun-seong; Kim, Duck-hee; Kim, Byung-gee

2012-01-01

293

Isotopic discrimination of nitrogen associated with biological nitrogen fixation on the system Rhizobium versus beans (Phaseolus vulgaris L.)  

International Nuclear Information System (INIS)

Two experiments were carried out in the greenhouse using a complete randomized experimental design. The first experiments was designed to assess the effect of three bean cultivars, inoculated with a mixture of efficient Rhizobium strains on the isotopic N discrimination at four development stages of beans plants. The second experiment was carried out to verify if there is any discrimination caused by the Rhizobium strains used. The plants of both experiments were grown in a N free medium, with 5 replicates. At the harvesting, ?N-15% was determined in the following parts of the bean plants: nodules, roots, shoots, cotyledons and pods. (author)

1989-01-01

294

Expression of the nodulation gene nodA in Rhizobium meliloti and localization of the gene product in the cytosol  

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The nodA gene of Rhizobium meliloti encodes a 21.8-kDa protein, which is conserved in several Rhizobium species. We overproduced the nodA protein as a fusion product with a portion of the ? cI repressor in Escherichia coli. This fusion protein was purified from inclusion bodies by gel and hydroxyapatite chromatography in the presence of NaDodSO4. Monospecific polyclonal antibodies against the hybrid protein were used to detect the nodA protein in the cytosol of E. coli and R. meliloti by imm...

Schmidt, Ju?rgen; John, Michael; Wieneke, Ursula; Kru?ssmann, Heinz-dieter; Schell, Jeff

1986-01-01

295

Two gene clusters of Rhizobium meliloti code for early essential nodulation functions and a third influences nodulation efficiency.  

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A pLAFR1 cosmid clone (pPP346) carrying the nodulation region of the symbiotic plasmid pRme41b was isolated from a gene library of Rhizobium meliloti 41 by direct complementation of a Nod- deletion mutant of R. meliloti. Agrobacterium tumefaciens and Rhizobium species containing pPP346 were able to form ineffective nodules on alfalfa. The 24-kilobase insert in pPP346 carries both the common nodulation genes and genes involved in host specificity of nodulation. It was shown that these two regi...

Putnoky, P.; Kondorosi, A.

1986-01-01

296

Study of final states involving 2 particle jets and missing energy with the DELPHI detector at LEP; Etude des etats finals contenant deux jets de particules et de l'energie manquante avec le detecteur DELPHI a LEP  

Energy Technology Data Exchange (ETDEWEB)

The observation of the Higgs boson would be of great importance for the understanding of the electroweak symmetry breaking. In the framework of the Minimal Supersymmetric extension of the Standard Model (MSSM), the lightest Higgs boson is neutral and scalar, and its mass must be less than 130 GeV/c{sup 2}. In this thesis, we have studied events characterized by the presence of two particle jets and missing energy. This is a very clear signature of the production of the Higgs boson in association with a Z{sup 0} boson. This production is followed by the decay of the Higgs boson into a bb-bar pair and the Z{sup 0} boson in {nu}{nu}-bar pair. In these studies, it is important to detect all particles in order to achieve a good resolution in energy. For these reasons, we have devoted ourselves to improving DELPHI's hermeticity mainly in the regions located at 40 deg C and 140 deg C. Using the data collected by the DELPHI detector at LEP in 1998 and in 1999 at four different energies in the centre of mass ({radical}s = 189, 196, 200 and 202 GeV), no signal has been observed, allowing us to exclude the Higgs boson at 95 % confidence level up to a mass of: m{sub H} > 98.0 (98.5) GeV/c{sup 2} at 95% C.L. this analysis; m{sub H} > 103.9 (106.3) GeV/c{sup 2} at 95% C.L. DELPHI combined. The values in parentheses show the expected limits and indicate the sensitivity of the analysis. If these results are interpreted in the framework of the MSSM we obtain: m{sub h} > 85.0 (85.3) GeV/c{sup 2} at 95% C.L. Studying the same topology, we have also searched for a Higgs boson decaying into a pair of non detectable particles (Invisible Higgs) in association with a Z{sup 0} boson decaying into a quark/antiquark pair. In this case too, no signal has been observed, which can be translated into a lower limit on the mass of the Higgs boson at 95% confidence level: m{sub h{sub inv}} > 105.5 (105.3) GeV/c{sup 2} at 95% C.L. Finally, we have measured the production cross section of a pair of Z{sup 0} bosons where one decays to a quark/antiquark pair (all flavours) and the other to a pair of neutrinos. The result is in very good agreement with the value predicted by the Standard Model: {sigma}{sup NC02}/{sigma}{sup MS} = 0.94{+-}0.25 this analysis; {sigma}{sup NC02}/{sigma}{sup MS} = 1.04{+-}0.12 DELPHI combined. (author)

Ferrer Ribas, E

2000-05-09

297

Caracterização química dos géis produzidos pelas bactérias diazotróficas Rhizobium tropici e Mesorhizobium sp. / Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp.  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPS RT) and Mesorhizobium sp (EPS MR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose (~ 1%). Chemical analysis showed the p [...] resence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPS RT and EPS MR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, ¹H and 13C-NMR.

Nilson Kobori, Monteiro; Gabriel, Aranda-Selverio; Diego Tadeu Degli, Exposti; Maria de Lourdes Corradi da, Silva; Eliana Gertrudes Macedo, Lemos; João Carlos, Campanharo; Joana Léa Meira, Silveira.

298

Seleksi Rhizobium Asal Tanaman Sengon (Paraserianthes Falcataria (L.) Nielsen) Terhadap Kemasaman Dan Aluminium (Screening Rhizobium From Sengon (Paraserianthes Falcataria (L.) Nielsen) To Acidity And Aluminum)  

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Study to find the Rhizobium strain that acid and Al tolerant was done in liquid medium in laboratory. The treatment was tested namely pH medium (4.0; 4.5; 5.0 and 5.5) and Al concentration (0.0; 0.6; 1.0; 3.5; and 10.0). The result showed that from 26 isolates was tested only 15 isolates (58%) can grow at pH 4.0 with Al concentration until 3.5 ppm. Unfortunately, there were no isolates can grow at 10.0 ppm. Based on visible turbidity (about 106 SPK.ml-1), only seven isolates (GR2 - 3, GR2 - 7...

Elfiati, Deni

2010-01-01

299

Kinetics study of pyridine biodegradation by a novel bacterial strain, Rhizobium sp. NJUST18.  

Science.gov (United States)

Biodegradation of pyridine by a novel bacterial strain, Rhizobium sp. NJUST18, was studied in batch experiments over a wide concentration range (from 100 to 1,000 mg l(-1)). Pyridine inhibited both growth of Rhizobium sp. NJUST18 and biodegradation of pyridine. The Haldane model could be fitted to the growth kinetics data well with the kinetic constants ?* = 0.1473 h(-1), K s = 793.97 mg l(-1), K i = 268.60 mg l(-1) and S m = 461.80 mg l(-1). The true ? max, calculated from ?*, was found to be 0.0332 h(-1). Yield coefficient Y X/S depended on S i and reached a maximum of 0.51 g g(-1) at S i of 600 mg l(-1). V max was calculated by fitting the pyridine consumption data with the Gompertz model. V max increased with initial pyridine concentration up to 14.809 mg l(-1) h(-1). The q S values, calculated from [Formula: see text], were fitted with the Haldane equation, yielding q Smax = 0.1212 g g(-1) h(-1) and q* = 0.3874 g g(-1) h(-1) at S m' = 507.83 mg l(-1), K s' = 558.03 mg l(-1), and K i' = 462.15 mg l(-1). Inhibition constants for growth and degradation rate value were in the same range. Compared with other pyridine degraders, ? max and S m obtained for Rhizobium sp. NJUST18 were relatively high. High K i and K i' values and extremely high K s and K s' values indicated that NJUST18 was able to grow on pyridine within a wide concentration range, especially at relatively high concentrations. PMID:24425539

Shen, Jinyou; Zhang, Xin; Chen, Dan; Liu, Xiaodong; Zhang, Libin; Sun, Xiuyun; Li, Jiansheng; Bi, Huiping; Wang, Lianjun

2014-06-01

300

CONFIRMING LOCATION OF NITROGEN FIXING GENES ON PLASMIDS IN RHIZOBIUM ISOLATED FROM PISUM SATIVUM  

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Full Text Available To confirm the location of the nitrogen fixing genes whether on the plasmids or on the genomic DNA the Rhizobial isolates isolated from pea (Pisum sativum were treated with acridine orange with various concentrations and fixed nitrogen was estimated from the media in which these rhizobia were grown. There was no significant difference in between the cured and non cured strains of the Rhizobium which proved that the nitrogen fixing genes are not plasmid borne but these are located on the genomic DNA.

Balaji Hajare and Avinash Ade1

2012-06-01

 
 
 
 
301

Mutagenesis in pea (Pisum sativum L.) as a tool for studying plant Rhizobium symbiosis  

International Nuclear Information System (INIS)

Pea mutants for symbiotic characteristics were obtained by treating seeds with ethylmethanesulphonate. They consisted of 15 mutants with no nodules (nod-), 10 mutants with inefficient nodules (nod+fix-) and four hypernodulating mutants (nod++nts) that also express a nitrate tolerant character of nodulation and fixation; 6, 7 and 1 loci, respectively, were identified. Strain specificity was found between a (nod+fix-) mutant and two Rhizobium leguminosarum strains. These isogenic mutants were also used in an agronomic study of nitrogen nutrition and in a cytological study to determine the stage at which abortion of symbiosis occurs. (author). 16 refs

1990-06-18

302

Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp  

International Nuclear Information System (INIS)

The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPSRT) and Mesorhizobium sp (EPSMR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose (? 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPSRT and EPSMR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, 1H and 13C-NMR. (author)

2012-01-01

303

Parallel variation in isoenzyme and nitrogen fixation markers in a Rhizobium population  

DEFF Research Database (Denmark)

Twenty isolates of Rhizobium leguminosarum bv. viceae were isolated at random from one field and examined for symbiotic plasmid fragment length polymorphisms and for isoenzyme patterns. The latter are most probably chromosome markers. With one exception both methods separated the isolates into the same 13 different groups. The largest group was represented 7 times according to isoenzymes and 8 times according to RFLP. This fixed non-random association of plasmid and chromosomal genotypes is consistent with a clonal population structure; it indicates limited exchange of plasmids under natural conditions. Seventeen isolates of 11 groups were highly effective and 2 isolates in one group almost ineffective.

Engvild, K.C.; Jensen, E.S.

1990-01-01

304

Physiological distinctions of pea symbiotic mutants with various nodulation level under inoculation by Rhizobium leguminosarum  

Directory of Open Access Journals (Sweden)

Full Text Available The study was focused on morphological and physiological peculiarities of pea plants with various nodulation ability under the infection by Rhizobium leguminosarum. Microscopic studies identified distinct features in formation of root nodules in different pea mutants. We revealed differences in the content of indole-acetic acid (IAA in mutants in the root zones differing by sensibility to R. leguminosarum. It was concluded that hormonal system of plants plays an important role in control of nodulation process, and emergence of mutations inducing disturbance of nodule-forming ability apparently depends on root hormonal status, in particular, IAA concentration ensuring both formation of nodule meristem and further organogenesis of the nodule.

Akimova G. P.

2012-11-01

305

Effects of microgravity on the binding of acetylsalicylic acid by Rhizobium leguminosarum bv. trifolii  

Science.gov (United States)

Bacteroids can be induced in vitro by treating growing Rhizobium leguminosarum bv. trifolii with succinic acid or succinic acid structural analogs like acetylsalicylic acid. Quantitating bacteroid induction by measuring acetylsalicylic binding under normal (1 g) conditions showed two forms of binding to occur. In one form of binding cells immediately bound comparatively high levels of acetylsalicylic acid, but the binding was quickly reversed. The second form of binding increased with time by first-order kinetics, and reached saturation in 40 s. Similar experiments performed in the microgravity environment aboard the NASA 930 aircraft showed only one form of binding and total acetylsalicylic acid bound was 32% higher than at 1 g.

Urban, James E.; Gerren, Richard; Zoelle, Jeffery

1995-07-01

306

Multiple copies of nodD in Rhizobium tropici CIAT899 and BR816.  

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Rhizobium tropici strains are able to nodulate a wide range of host plants: Phaseolus vulgaris, Leucaena spp., and Macroptilium atropurpureum. We studied the nodD regulatory gene for nodulation of two R. tropici strains: CIAT899, the reference R. tropici type IIb strain, and BR816, a heat-tolerant strain isolated from Leucaena leucocephala. A survey revealed several nodD-hybridizing DNA regions in both strains: five distinct regions in CIAT899 and four distinct regions in BR816. Induction exp...

Rhijn, P. J.; Feys, B.; Verreth, C.; Vanderleyden, J.

1993-01-01

307

Exo-Oligosaccharides of Rhizobium sp. Strain NGR234 Are Required for Symbiosis with Various Legumes  

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Rhizobia are nitrogen-fixing bacteria that establish endosymbiotic associations with legumes. Nodule formation depends on various bacterial carbohydrates, including lipopolysaccharides, K-antigens, and exopolysaccharides (EPS). An acidic EPS from Rhizobium sp. strain NGR234 consists of glucosyl (Glc), galactosyl (Gal), glucuronosyl (GlcA), and 4,6-pyruvylated galactosyl (PvGal) residues with ?-1,3, ?-1,4, ?-1,6, ?-1,3, and ?-1,4 glycoside linkages. Here we examined the role of NGR234 gen...

Staehelin, Christian; Forsberg, Lennart S.; D Haeze, Wim; Gao, Mu-yun; Carlson, Russell W.; Xie, Zhi-ping; Pellock, Brett J.; Jones, Kathryn M.; Walker, Graham C.; Streit, Wolfgang R.; Broughton, William J.

2006-01-01

308

Rhizobium sp. strain NGR234 NodZ protein is a fucosyltransferase.  

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Rhizobium sp. strain NGR234 produces a large family of lipochitooligosaccharide Nod factors carrying specific substituents. Among them are 3-O- (or 4-O-) and 6-O-carbamoyl groups, an N-methyl group, and a 2-O-methylfucose residue which may bear either 3-O-sulfate or 4-O-acetyl substitutions. Investigations on the genetic control of host specificity revealed a number of loci which directly affect Nod factor structure. Here we show that insertion and frameshift mutations in the nodZ gene abolis...

Quesada-vincens, D.; Fellay, R.; Nasim, T.; Viprey, V.; Burger, U.; Prome, J. C.; Broughton, W. J.; Jabbouri, S.

1997-01-01

309

Rhizobium sp. Strain NGR234 Possesses a Remarkable Number of Secretion Systems? †  

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Rhizobium sp. strain NGR234 is a unique alphaproteobacterium (order Rhizobiales) that forms nitrogen-fixing nodules with more legumes than any other microsymbiont. We report here that the 3.93-Mbp chromosome (cNGR234) encodes most functions required for cellular growth. Few essential functions are encoded on the 2.43-Mbp megaplasmid (pNGR234b), and none are present on the second 0.54-Mbp symbiotic plasmid (pNGR234a). Among many striking features, the 6.9-Mbp genome encodes more different secr...

Schmeisser, Christel; Liesegang, Heiko; Krysciak, Dagmar; Bakkou, Nadia; Le Que?re?, Antoine; Wollherr, Antje; Heinemeyer, Isabelle; Morgenstern, Burkhard; Pommerening-ro?ser, Andreas; Flores, Margarita; Palacios, Rafael; Brenner, Sydney; Gottschalk, Gerhard; Schmitz, Ruth A.; Broughton, William J.

2009-01-01

310

Rhizobium leguminosarum hupE Encodes a Nickel Transporter Required for Hydrogenase Activity?  

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Synthesis of the hydrogen uptake (Hup) system in Rhizobium leguminosarum bv. viciae requires the function of an 18-gene cluster (hupSLCDEFGHIJK-hypABFCDEX). Among them, the hupE gene encodes a protein showing six transmembrane domains for which a potential role as a nickel permease has been proposed. In this paper, we further characterize the nickel transport capacity of HupE and that of the translated product of hupE2, a hydrogenase-unlinked gene identified in the R. leguminosarum genome. Hu...

Brito, Bele?n; Prieto, Rosa-isabel; Cabrera, Ezequiel; Mandrand-berthelot, Marie-andre?e; Imperial, Juan; Ruiz-argu?eso, Toma?s; Palacios, Jose?-manuel

2010-01-01

311

Electron transport components involved in hydrogen oxidation in free-living Rhizobium japonicum.  

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Membranes from free-living Rhizobium japonicum were isolated to study electron transport components involved in H2 oxidation. The H2/O2 uptake rate ratio in membranes was approximately 2. The electron transport inhibitors antimycin A, cyanide, azide, hydroxylamine, and 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO) inhibited H2 uptake and H2-dependent O2 uptake significantly. H2-reduced minus O2-oxidized absorption difference spectra revealed peaks at 551.5, 560, and 603 nm, indicating the invo...

1982-01-01

312

Molecular cloning and genetic organization of C4-dicarboxylate transport genes from Rhizobium leguminosarum.  

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Cosmids containing C4-dicarboxylate transport (dct) genes were identified from a gene bank of Rhizobium leguminosarum DNA made in the broad-host-range vector pLAFR1 by their ability to complement R. trifolii dct mutants. The dct genes were further characterized by subcloning, restriction site mapping, and transposon Tn5 and Tn7 mutageneses. Three dct loci were identified within a 5.5-kilobase region of DNA, in the order dctA-dctB-dctC. The results suggested that dctA encoded a structural comp...

Ronson, C. W.; Astwood, P. M.; Downie, J. A.

1984-01-01

313

Rhizobium japonicum mutants that are hypersensitive to repression of H2 uptake by oxygen.  

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The synthesis of an H2 oxidation system in free-living Rhizobium japonicum wild-type strain SR is repressed by oxygen. Maximal H2 uptake rates were obtained in strain SR after derepression in 11 microM or less dissolved oxygen. Oxygen levels above 45 microM completely repressed H2 uptake in strain SR. Five R. japonicum mutant strains that are hypersensitive to repression or H2 oxidation by oxygen were derived from strain SR. The mutants were obtained by screening H2 uptake-negative mutants th...

Maier, R. J.; Merberg, D. M.

1982-01-01

314

Transposon Tn5-induced mutagenesis of Rhizobium japonicum yielding a wide variety of mutants.  

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When the "suicide" vector pSUP1011, which carries transposon Tn5 (Kmr), was introduced into Rhizobium japonicum USDA 110, kanamycin-resistant (Kmr) colonies were detected at a frequency (4.2 X 10-6) ca. 30 times greater than the spontaneous kanamycin resistance frequency (1.4 X 10-7). Ten thousand Kmr mutants were isolated and tested for nutritional auxotrophy. Auxotrophs were detected at a frequency of 0.5%. The following classes of auxotrophs were identified: adenine- (three), histi...

1984-01-01

315

Production of Rhizobium Inoculants for Lupinus nootkatensis on Nutrient-Supplemented Pumice  

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The use of the legume Lupinus nootkatensis as a pioneer plant to fight soil erosion and to reclaim eroded soils in Iceland has been under development for a few years. Production of a robust, low-cost bacterial inoculant was therefore a prerequisite for the extended use of this plant. Volcanic pumice is a naturally expanded mineral which is available in vast amounts in Iceland. It was tested as a carrier for solid fermentation of Rhizobium lupini. Nutrient-supplemented pumice containing a smal...

1993-01-01

316

Bacteriophage that can distinguish between wild-type Rhizobium japonicum and a non-nodulating mutant.  

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A bacteriophage (phage TN1) that lyses Rhizobium japonicum 3I1b110 was isolated from Tennessee soil. Structurally, this phage resembles the Escherichia coli phage T4, having an icosahedral head (47 by 60 nm) and a contractile tail (17 by 80 nm). An interesting feature of this phage is that it lyses all of the symbiotic defective mutants derived from R. japonicum 3I1b110 that were tested, except one, mutant strain HS123. Mutant strain HS123 is a non-nodulating mutant that is defective in attac...

Stacey, G.; Pocratsky, L. A.; Puvanesarajah, V.

1984-01-01

317

Identification and analysis of the dissimilatory nitrous oxide reduction genes, nosRZDFY, of Rhizobium meliloti.  

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The complete nos region essential for dissimilatory nitrous oxide reduction by the endosymbiotic diazotroph Rhizobium meliloti was identified in a cosmid (pYC7) carrying a 10.1-kb EcoRI fragment of the nod megaplasmid. This gene region was localized by Southern hybridization and Tn5 mutagenesis to within 8 kb downstream from the fixGHIS cluster. Nucleotide sequence determination of a 4.6-kb DNA segment including the structural gene nosZ and its flanking regions showed sequence homology and si...

Holloway, P.; Mccormick, W.; Watson, R. J.; Chan, Y. K.

1996-01-01

318

A second exopolysaccharide of Rhizobium meliloti strain SU47 that can function in root nodule invasion.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rhizobium meliloti strain SU47 produces the calcofluor-binding exopolysaccharide, succinoglycan, that is required for alfalfa root nodule invasion. Strains derived from R. meliloti SU47 secreted an acidic exopolysaccharide, EPSb, that replaced succinoglycan in nodule invasion. EPSb, which has not formerly been identified among the Rhizobiaceae, consisted of the repeating unit 4,6-O-(1-carboxyethylidene)-alpha-D-Galp1----3(X-O-Ac)-beta-D-G lcp1----3. EPSb synthesis occurred either in strains c...

Zhan, H. J.; Levery, S. B.; Lee, C. C.; Leigh, J. A.

1989-01-01

319

High-frequency induction of nodulation and nitrogen fixation mutants of Rhizobium japonicum.  

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More than 50 symbiotic mutants of Rhizobium japonicum were isolated by purported plasmid-curing techniques. Wild-type R. japonicum strains were grown in liquid culture at 28 or 36 degrees C in different concentrations of acridine orange, ethidium bromide, or sodium dodecyl sulfate for selection of mutants. The symbiotic traits of 133 isolates from nine treatment groups were determined. Forty-two isolates were Nod- Nif+, seven were Nod+ Nif-, and two were Nod- Nif-. The nifDH genes were delete...

Skogen-hagenson, M. J.; Atherly, A. G.

1983-01-01

320

Thermophilic, Reversible ?-Resorcylate Decarboxylase from Rhizobium sp. Strain MTP-10005: Purification, Molecular Characterization, and Expression  

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We found the occurrence of thermophilic reversible ?-resorcylate decarboxylase (?-RDC) in the cell extract of a bacterium isolated from natural water, Rhizobium sp. strain MTP-10005, and purified the enzyme to homogeneity. The molecular mass of the enzyme was determined to be about 151 kDa by gel filtration, and that of the subunit was 37.5 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; in other words, the enzyme was a homotetramer. The enzyme was induced specifically by ...

Yoshida, Masahiro; Fukuhara, Nobuhiro; Oikawa, Tadao

2004-01-01

 
 
 
 
321

Effects of Heavy Metal from Polluted Soils on the Rhizobium Diversity  

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Heavy metals adversely influence microorganisms, affecting their growth, abundance, genetic diversity, nodulation ability and efficacy. The aim of this study was to isolate and characterize free-leaving Rhizobium from soil which were artificially polluted with Cu (100, 250, and 500 mg kg-1 soil), Zn (300, 700, and 1500 mg kg-1 soil) and Pb (50, 250, and 1000 mg kg-1 soil), but also with a mixture of all these metals, and cultivated with red clover (Trifolium pratense L.), and to compare them ...

Stan, Vasilica; Gament, Eugenia; Cornea, Ca?lina Petrut?a; Voaides?, Ca?ta?lina; Dus?a, Mirela; Plopeanu, Georgiana

2011-01-01

322

Mapping of the protein-coding regions of Rhizobium meliloti common nodulation genes  

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An 8.5-kb EcoRI fragment containing the common nod region of the megaplasmid pRme41b of Rhizobium meliloti was recloned in plasmids of Escherichia coli, and a detailed restriction map was established. The region can express at least eight proteins in E. coli minicells and in an in vitro transcription/translation system, prepared from E. coli. Protein coding regions were determined by subcloning of restriction fragments, deletion mutations and by transposon mutagenesis. The coding regions for ...

Schmidt, Ju?rgen; John, Michael; Kondorosi, Eva; Kondorosi, Adam; Wieneke, Ursula; Schro?der, Gudrun; Schro?der, Joachim; Schell, Jeff

1984-01-01

323

Biosynthesis and degradation of nodule-specific Rhizobium loti compounds in Lotus nodules.  

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Two nodule-specific Rhizobium loti compounds were identified in Lotus tenuis and Lotus pedunculatus nodules induced by strain NZP2037. One, a silver nitrate-positive cation called rhizolotine, has been characterized as the riboside of a novel alpha-hydroxyimino acid containing a 1,4,5,6-tetrahydropyrimidine ring (G. J. Shaw, R. D. Wilson, G. A. Lane, L. D. Kennedy, D. B. Scott, and G. J. Gainsford, J. Chem. Soc. Chem. Commun., p. 180-181, 1986), and the other, yellow-1, stains yellow with nin...

1987-01-01

324

Effectiveness of Rhizobium Strains Used in Inoculants after Their Introduction into Soil  

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Rhizobium strains used in inoculants for Trifolium spp., Medicago spp., Glycine max, and Lotus pedunculatus were isolated from nodules of these legumes grown in soils into which the rhizobia had been introduced 4 to 8 years before. Isolations were made from a total of 420 nodules. Nodule occupancy by the inoculant strains varied from 17.7% for a soybean strain to 100% in the case of L. pedunculatus whose specific rhizobia did not occur in the soils studied. In general, inoculant strains isola...

1985-01-01

325

Associação de Rhizobium sp. a duas leguminosas na tolerância à atrazina Association of Rhizobium sp. with two legumes on atrazine tolerance  

Directory of Open Access Journals (Sweden)

Full Text Available A associação de bactérias a plantas tem sido estudada como uma possível tecnologia emergente, para fitorremediação de contaminantes, entre eles os herbicidas, que, por sua recalcitrância, ameaçam a qualidade do ambiente. O objetivo deste trabalho foi verificar a tolerância de mucuna-anã (Stizolobium deeringianum Bort e mucuna-preta (Stizolobium aterrimum Piper & Tracy, inoculadas e não inoculadas com Rhizobium sp., ao herbicida atrazina. Os tratamentos foram: plantas com inoculante + 0,1 g/m², 0,2 g/m² atrazina e sem atrazina (T1, T2 e T3, respectivamente, sem inoculante + 0,1 g/m², 0,2 g/m² atrazina e sem atrazina (T4, T5 e T6, respectivamente. O delineamento experimental utilizado foi inteiramente casualizado, com três repetições. Foram avaliados germinação, sobrevivência, número de nódulos, altura, biomassa verde, biomassa seca da parte aérea, após o crescimento das plantas por 50 dias em casa de vegetação. Nos tratamentos com inoculante, avaliou-se a porcentagem de germinação de plantas bioindicadoras (Bidens pilosa L.. Mucuna-preta e mucuna-anã demonstraram maior tolerância ao herbicida quando associadas ao Rhizobium. Os valores de sobrevivência de mucuna-preta, nas doses 0,1 e 0,2 g/m² de atrazina (T1 e T2, foram de 34 a 24% superiores aos observados nas mesmas doses, mas sem o inoculante (T4 e T5. Para mucuna-anã, T1 e T2 foram de 17 e 8% superiores a T4 e T5, respectivamente. As alturas médias de mucuna-anã em T1, T2 e T3 foram mais elevadas que em T4, T5 e T6, reforçando a importância do simbionte à resistência ao herbicida. Os resultados encontrados para as variáveis altura, biomassa verde e seca para mucuna-preta não apresentaram diferença estatística entre os tratamentos com e sem inoculante, mostrando uma resistência natural à atrazina e a possibilidade de atuar como planta remediadora. A germinação de B. pilosa indica uma possível degradação da atrazina no solo com ambas as espécies de mucunas inoculadas com Rhizobium sp.The association of bacteria with plants has been studied as a possible emerging technology for phytoremediation of contaminants, including herbicides, which pose as a threatening to environmental quality due to their recalcitrance. The aim of this study was to assess the tolerance of dwarf mucuna (Stizolobium deeringianum Bort and black mucuna (Stizolobium aterrimum Piper & Tracy inoculated and uninoculated with Rhizobium to the herbicide atrazine. The treatments were: plants with inoculant + 0.1 g/m², 0.2 g/m² atrazine, and without atrazine (T1, T2 and T3, respectively, plants without inoculant + 0.1 g/m², 0.2 g/m² atrazine and without atrazine (T4, T5 and T6, respectively. The experiment was arranged in a completely randomized design, with three replications. Plants were grown in a greenhouse for 50 days and the variables germination, survival, number of nodules, height, green/dry biomass of the aerial part were evaluated. In the treatments with inoculants, the germination percentage of bioindicator plants (Bidens pilosa L. was also evaluated. Black mucuna and dwarf mucuna showed greater tolerance to the herbicide when associated with Rhizobium. The survival rates of black mucuna at the doses 0.1 and 0.2 g/m² atrazine (T1 and T2 were 34 and 24% higher than those observed at the same doses, but without the inoculant (T4 and T5. For dwarf mucuna, T1 and T2 were 17 and 8% higher than T4 and T5, respectively. The average heights of dwarf mucuna in T1, T2 and T3 were higher than in T4, T5 and T6, reinforcing the importance of the symbiont to the herbicide resistance. The results found for the variables height, green and dry biomass for black mucuna were not significantly different among the treatments with and without inoculant, showing a natural resistance to atrazine and the possibility of acting as a remediation plant. The germination of B. pilosa indicates a possible degradation of atrazine in the soil by both mucuna species inoculated with Rhizobium sp.

Danielle Camargo

2011-08-01

326

The structure and molecular mechanics calculations of the cyclic (1 ? 2)-?- D-glucan secreted by Rhizobium tropici CIAT 899  

Science.gov (United States)

The structure of the extracellular cyclic (1 ? 2)-?- D-glucan secreted by Rhizobium tropici CIAT 899 has been studied by methylation analysis, 1D and 2D NMR experiments, HPLC and FAB-MS. Molecular mechanics (MM2) and theoretical 3JHH coupling constants calculations were performed.

Gil Serrano, Antonio M.; Franco-Rodríguez, Guillermo; González-Jiménez, Isabel; Tejero-Mateo, Pilar; Molina, José Molina; Dobado, J. A.; Megías, Manuel; Romero, Maria Jesús

1993-12-01

327

The acetyl substituent of succinoglycan is not necessary for alfalfa nodule invasion by Rhizobium meliloti Rm1021.  

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Rhizobium meliloti Rm1021 requires a Calcofluor-binding exopolysaccharide, termed succinoglycan or EPS I, to invade alfalfa nodules. We have determined that a strain carrying a mutation in the exoZ locus produces succinoglycan that lacks the acetyl substituent. The exoZ mutant nodules alfalfa normally.

Reuber, T. L.; Walker, G. C.

1993-01-01

328

Multilocus Sequence-Based Analysis Delineates a Clonal Population of Agrobacterium (Rhizobium) radiobacter (Agrobacterium tumefaciens) of Human Origin ?  

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The genus Agrobacterium includes plant-associated bacteria and opportunistic human pathogens. Taxonomy and nomenclature within the genus remain controversial. In particular, isolates of human origin were all affiliated with the species Agrobacterium (Rhizobium) radiobacter, while phytopathogenic strains were designated under the synonym denomination Agrobacterium tumefaciens. In order to study the relative distribution of Agrobacterium strains according to their origins, we performed a multil...

Aujoulat, Fabien; Jumas-bilak, Estelle; Masnou, Agne?s; Salle?, Fanny; Faure, Denis; Segonds, Christine; Marchandin, He?le?ne; Teyssier, Corinne

2011-01-01

329

Joint Evolution of Kin Recognition and Cooperation in Spatially Structured Rhizobium Populations  

Science.gov (United States)

In the face of costs, cooperative interactions maintained over evolutionary time present a central question in biology. What forces maintain this cooperation? Two potential ways to explain this problem are spatially structured environments (kin selection) and kin-recognition (directed benefits). In a two-locus population genetic model, we investigated the relative roles of spatial structure and kin recognition in the maintenance of cooperation among rhizobia within the rhizobia-legume mutualism. In the case where the cooperative and kin recognition loci are independently inherited, spatial structure alone maintains cooperation, while kin recognition decreases the equilibrium frequency of cooperators. In the case of co-inheritance, spatial structure remains a stronger force, but kin recognition can transiently increase the frequency of cooperators. Our results suggest that spatial structure can be a dominant force in maintaining cooperation in rhizobium populations, providing a mechanism for maintaining the mutualistic nodulation trait. Further, our model generates unique and testable predictions that could be evaluated empirically within the legume-rhizobium mutualism.

Zee, Peter C.; Bever, James D.

2014-01-01

330

Effectiveness and competing capacity of native Rhizobium strains evaluated in IX Region soils  

International Nuclear Information System (INIS)

Symbiotic nitrogen fixation in legumes reaches its optimum when the host plants are nodulated by highly competitive and effective Rhizobium strains. With the purpose of assessing competition and nitrogen fixing capacity of native Rhizobium leguminosarum bio-var trifolii strains, a greenhouse test was carried out using white clover (Trifolium re-pens) and four kinds of soils, which represent the main agroecological areas of the IX Region. Eleven strains were evaluated, they were both native and collected and were streptomycin sulphate antibiotic resistant. A nitrogen and a nitrogen-less without inoculation testers were used as controls. All pots received a solution of ammonium sulphate marked with 10% 15 N a.e, equivalent to 10 kg ha-1 of N. Rye-grass was used as reference crop, cv. Nu-i. In general, the evaluated strains were very efficient. After three or four cuts they became the only source of nitrogen for the plants. They were also very competitive, getting to over 70% of root infection with regard to those present in soils. In Curacautin and Tolten soils, biological nitrogen fixation begins later than other soils evaluated, which is coincident with soils having a higher nitrogen content. Symbiosis occurs when the soil nitrogen content exhausts or diminishes. (author)

1995-01-01

331

Variability of isolated colonies in bean nodulating Rhizobium strains before and after exposure to high temperature  

Directory of Open Access Journals (Sweden)

Full Text Available Irregular response to bean plants to Rhizobium inoculation has been attributed to among other factors, low competitive ability, low N2 fixation efficiency and genetic instability of the symbiont. This genetic instability caused by high rates of genomic rearrangements and/or plasmid deletions can be accentuated by high temperatures. This fact may limit the utilization of these strains as inoculants, especially in tropical soils. In this study, the variability of isolated colonies derived from effective R. leguminosarum bv. phaseoli (SLP1.3 and BR 10.026 and R tropici (SLA2.2 and BR322 strains was evaluated before and after exposure to high temperatures (four consecutive thermal shocks at 45masculineC. This evaluation involved plant dry matter analysis of inoculated plants and genotypic (plasmid profile and genomic patterns via RAPD analysis of the Rhizobium strains. The results evidenced that high temperature improve the natural performance variability especially between isolated colonies from R. leguminosarum bv. phaseoli strains. The plasmid profile of isolated colonies from R. tropici strains were identical regardless of temperature treatment whereas isolated colonies from R. leguminosarum bv. phaseoli alterations were detected especially after the thermal treatment. The genomic patterns generated by AP-PCR showed more alterations and genetic variation in isolated colonies from R. leguminosarum bv. phaseoli strains indicating that R. tropici strains are more stable and lower affected by high temperature.

Raposeiras Rui

2002-01-01

332

Extended region of nodulation genes in Rhizobium meliloti 1021. I. Phenotypes of Tn5 insertion mutants  

International Nuclear Information System (INIS)

Rhizobium meliloti Nod- mutant WL131, a derivative of wild-type strain 102F51, was complemented by a clone bank of wild-type R. meliloti 1021 DNA, and clone pRmJT5 was recovered. Transfer of pRmJT5 conferred alfalfa nodulation on other Rhizobium species, indicating a role in host range determination for pRmJT5. Mutagenesis of pRmJT5 revealed several segments in which transposon insertion causes delay in nodulation, and/or marked reduction of the number of nodules formed on host alfalfa plants. The set of mutants indicated five regions in which nod genes are located; one mutant, nod-216, is located in a region not previously reported to encode a nodulation gene. Other mutant phenotypes correlated with the positions of open reading frames for nodH, nodF and nodE, and with a 2.2-kb EcoRI fragment. A mutant in nodG had no altered phenotype in this strain. One nodulation mutant was shown to be a large deletion of the common nod gene region. The authors present a discussion comparing the various studies made on this extended nod gene region

1987-01-01

333

Studies on Nodulation, Biochemical Analysis and Protein Profiles of Rhizobium Isolated From Indigofera species  

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Full Text Available Nodulation characteristics in five species of Indigofera viz., I .trita, I. linnaei, I. astragalina, I. parviflora and I. viscosa was studied at regular intervals on the plants raised in garden soil. Among the species studied, highest average number of nodules per plant of 23 with maximum sized nodules of 8.0 mm diameter was observed in I. astragalina. Biochemical analysis of root nodules of I. astragalina revealed that the leghaemoglobin content of nodules and nitrogen content of root, shoot, leaves and nodules were gradually increased up to 60 DAS, and then decreased with increase in age. Rhizobium isolates of five species of Indigofera were isolated and screened for enzymatic activities and total cellular protein profiles. All the five isolates showed nitrate reductase, citrase, tryptophanase and catalase activity while much variation was observed for enzymes like gelatinase, urease, caseinase, lipase, amylase, lysine decarboxylase and protease activities. Among the isolates studied, only the isolate from I. viscosa has the ability to solubilize the insoluble tricalcium phosphate. All the Rhizobium isolates exhibit similarity in protein content, except the isolate from I. viscosa which showed one additional protein band.

Kumari, B. S.

2010-01-01

334

Production of Proteasome Inhibitor Syringolin A by the Endophyte Rhizobium sp. Strain AP16.  

Science.gov (United States)

Syringolin A, the product of a mixed nonribosomal peptide synthetase/polyketide synthase encoded by the syl gene cluster, is a virulence factor secreted by certain Pseudomonas syringae strains. Together with the glidobactins produced by a number of beta- and gammaproteobacterial human and animal pathogens, it belongs to the syrbactins, a structurally novel class of proteasome inhibitors. In plants, proteasome inhibition by syringolin A-producing P. syringae strains leads to the suppression of host defense pathways requiring proteasome activity, such as the ones mediated by salicylic acid and jasmonic acid. Here we report the discovery of a syl-like gene cluster with some unusual features in the alphaproteobacterial endophyte Rhizobium sp. strain AP16 that encodes a putative syringolin A-like synthetase whose components share 55% to 65% sequence identity (72% to 79% similarity) at the amino acid level. As revealed by average nucleotide identity (ANI) calculations, this strain likely belongs to the same species as biocontrol strain R. rhizogenes K84 (formely known as Agrobacterium radiobacter K84), which, however, carries a nonfunctional deletion remnant of the syl-like gene cluster. Here we present a functional analysis of the syl-like gene cluster of Rhizobium sp. strain AP16 and demonstrate that this endophyte synthesizes syringolin A and some related minor variants, suggesting that proteasome inhibition by syrbactin production can be important not only for pathogens but also for endophytic bacteria in the interaction with their hosts. PMID:24727275

Dudnik, Alexey; Bigler, Laurent; Dudler, Robert

2014-06-15

335

Characterization of NopP, a type III secreted effector of Rhizobium sp. strain NGR234.  

Science.gov (United States)

The type three secretion system (TTSS) encoded by pNGR234a, the symbiotic plasmid of Rhizobium sp. strain NGR234, is responsible for the flavonoid- and NodD1-dependent secretion of nodulation outer proteins (Nops). Abolition of secretion of all or specific Nops significantly alters the nodulation ability of NGR234 on many of its hosts. In the closely related strain Rhizobium fredii USDA257, inactivation of the TTSS modifies the host range of the mutant so that it includes the improved Glycine max variety McCall. To assess the impact of individual TTSS-secreted proteins on symbioses with legumes, various attempts were made to identify nop genes. Amino-terminal sequencing of peptides purified from gels was used to characterize NopA, NopL, and NopX, but it failed to identify SR3, a TTSS-dependent product of USDA257. By using phage display and antibodies that recognize SR3, the corresponding protein of NGR234 was identified as NopP. NopP, like NopL, is an effector secreted by the TTSS of NGR234, and depending on the legume host, it may have a deleterious or beneficial effect on nodulation or it may have little effect. PMID:15231809

Ausmees, Nora; Kobayashi, Hajime; Deakin, William J; Marie, Corinne; Krishnan, Hari B; Broughton, William J; Perret, Xavier

2004-07-01

336

The role of GSTs in the tolerance of Rhizobium leguminosarum to cadmium.  

Science.gov (United States)

A high intraspecific difference in cadmium (Cd) tolerance exits among Rhizobium leguminosarum strains. The higher tolerance to Cd appeared to be related to the efficiency of the glutathione (GSH)-Cd chelation mechanism, but it is not known how efficiency is influenced. Thus, in this work it was intended to investigate the traits behind the efficiency of intracellular Cd chelation by GSH. Glutathione-S-transferases (GST; EC 2.5.1.18) are a family of multi-functional dimeric proteins, found in both prokaryotes and eukaryotes, which are implicated in a variety of stress conditions. The common feature of these enzymes is to catalyze the conjugation of the sulfur atom of GSH with a large variety of hydrophobic toxic compounds of both endogenous and exogenous origin. Taking into account the reactions catalyzed by GSTs, it was hypothesized that they could be involved in the GSH-Cd complex formation in R. leguminosarum. Differences in GSTs activity between strains could explain variation in Cd chelation efficiency detected among strains and, consequently, discrepancy in tolerance to Cd. Thus, GST isoforms of R. leguminosarum strains with distinct tolerances to Cd were purified and their activity investigated. The relationship between chelation efficiency and enzymatic activity of GSTs was demonstrated, supporting the hypothesis that GSTs, in particular one isoform, was involved in the formation of GSH-Cd complexes and in the tolerance of Rhizobium to Cd. PMID:23907727

Corticeiro, Sofia; Freitas, Rosa; Figueira, Etelvina

2013-12-01

337

Effectiveness of Rhizobium strains used in inoculants after their introduction into soil.  

Science.gov (United States)

Rhizobium strains used in inoculants for Trifolium spp., Medicago spp., Glycine max, and Lotus pedunculatus were isolated from nodules of these legumes grown in soils into which the rhizobia had been introduced 4 to 8 years before. Isolations were made from a total of 420 nodules. Nodule occupancy by the inoculant strains varied from 17.7% for a soybean strain to 100% in the case of L. pedunculatus whose specific rhizobia did not occur in the soils studied. In general, inoculant strains isolated from nodules did not differ in effectiveness from cultures of the same strains concurrently maintained in lyophilized form. The average effectiveness of all of the isolates (identified and unidentified) from a legume was 7.1 to 73.3% higher than that of the unidentified isolates alone, demonstrating the prolonged effect that a single-seed inoculation has on the rhizobial population in a soil which had not been planted with legumes before. Relatively weak recovery of a Rhizobium japonicum strain introduced into soil 4 years after soybean seed inoculated with a different strain had been planted in the same soil confirmed the advantage of a resident population over an introduced inoculant strain. PMID:16346692

van Rensburg, H J; Strijdom, B W

1985-01-01

338

Role of Rhizobium endoglucanase CelC2 in cellulose biosynthesis and biofilm formation on plant roots and abiotic surfaces  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The synthesis of cellulose is among the most important but poorly understood biochemical processes, especially in bacteria, due to its complexity and high degree of regulation. In this study, we analyzed both the production of cellulose by all known members of the Rhizobiaceae and the diversity of Rhizobium celABC operon predicted to be involved in cellulose biosynthesis. We also investigated the involvement in cellulose production and biofilm formation of celC gene encoding an endoglucanase (CelC2 that is required for canonical symbiotic root hair infection by Rhizobium leguminosarum bv. trifolii. Results ANU843 celC mutants lacking (ANU843?C2 or overproducing cellulase (ANU843C2+ produced greatly increased or reduced amounts of external cellulose micro fibrils, respectively. Calcofluor-stained cellulose micro fibrils were considerably longer when formed by ANU843?C2 bacteria rather than by the wild-type strain, in correlation with a significant increase in their flocculation in batch culture. In contrast, neither calcofluor-stained extracellular micro fibrils nor flocculation was detectable in ANU843C2+ cells. To clarify the role of cellulose synthesis in Rhizobium cell aggregation and attachment, we analyzed the ability of these mutants to produce biofilms on different surfaces. Alteration of wild-type CelC2 levels resulted in a reduced ability of bacteria to form biofilms both in abiotic surfaces and in planta. Conclusions Our results support a key role of the CelC2 cellulase in cellulose biosynthesis by modulating the length of the cellulose fibrils that mediate firm adhesion among Rhizobium bacteria leading to biofilm formation. Rhizobium cellulose is an essential component of the biofilm polysaccharidic matrix architecture and either an excess or a defect of this “building material” seem to collapse the biofilm structure. These results position cellulose hydrolytic enzymes as excellent anti-biofilm candidates.

Robledo M

2012-09-01

339

Evapotranspiration (ET) covers.  

Science.gov (United States)

Evapotranspiration (ET) cover systems are increasingly being used at municipal solid waste (MSW) landfills, hazardous waste landfills, at industrial monofills, and at mine sites. Conventional cover systems use materials with low hydraulic permeability (barrier layers) to minimize the downward migration of water from the surface to the waste (percolation), ET cover systems use water balance components to minimize percolation. These cover systems rely on soil to capture and store precipitation until it is either transpired through vegetation or evaporated from the soil surface. Compared to conventional membrane or compacted clay cover systems, ET cover systems are expected to cost less to construct. They are often aesthetic because they employ naturalized vegetation, require less maintenance once the vegetative system is established, including eliminating mowing, and may require fewer repairs than a barrier system. All cover systems should consider the goals of the cover in terms of protectiveness, including the pathways of risk from contained material, the lifecycle of the containment system. The containment system needs to be protective of direct contact of people and animals with the waste, prevent surface and groundwater water pollution, and minimize release of airborne contaminants. While most containment strategies have been based on the dry tomb strategy of keeping waste dry, there are some sites where adding or allowing moisture to help decompose organic waste is the current plan. ET covers may work well in places where complete exclusion of precipitation is not needed. The U.S. EPA Alternative Cover Assessment Program (ACAP), USDOE, the Nuclear Regulatory Commission, and others have researched ET cover design and efficacy, including the history of their use, general considerations in their design, performance, monitoring, cost, current status, limitations on their use, and project specific examples. An on-line database has been developed with information about specific projects using ET covers. There are three general approaches for non-conventional cover systems to achieve approval for installation; the first is when equivalent performance to conventional final cover systems can be demonstrated directly on site. This is the approach used by the Sandia study, by most ACAP sites, and the Rocky Mountain Arsenal. A second approach is used when there are data from a site specific study such as an ACAP installation at a site that has analogous soil and climate conditions. Several sites in Colorado and Southern California have achieved approval based on data from similar sites. The third most common approach for regulatory approval is by installation of data collection systems with the agreement that the permanence of the ET cover installation is contingent on success of the cover in meeting certain performance goals. This article is intended as an introduction to the topic and is not intended to serve as guidance for design or construction, nor indicate the appropriateness of using an ET cover systems at a particular site. PMID:22574378

Rock, Steve; Myers, Bill; Fiedler, Linda

2012-01-01

340

Respuesta fisiológica del Frijol Caupí (Vigna unguiculata (l.) Walp) a la coinoculación de bacterias Diazotróficas de los géneros Azotobacter y Rhizobium en suelos del Departamento del Cesar  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Obando Castellanos , Dolly Melissa (2012) Respuesta fisiológica del Frijol Caupí (Vigna unguiculata (l.) Walp) a la coinoculación de bacterias Diazotróficas de los géneros Azotobacter y Rhizobium en suelos del Departamento del Cesar. Maestría thesis, Universidad Nacional de Colombia.

2012-01-01

 
 
 
 
341

Rapport final de la Collaboration CERN-CNRS pour la construction du LHC Accord Technique d'Exécution No 2 Cryostats et assemblage des sections droites courtes (SSS) du LHC  

CERN Multimedia

Depuis 1995 et suite à la signature du protocole de Collaboration, le CERN, le CEA et le CNRS ont étroitement collaboré dans le cadre de la contribution exceptionnelle de la France à la construction du LHC. Pour le CNRS, l'Institut de Physique Nucléaire d'Orsay a pris en charge deux Accords Techniques d'Exécution. Le premier concerne la conception et l'assemblage des Sections Droites Courtes de la machine, et le deuxième, l'étalonnage des thermomètres cryogéniques du LHC. Dans le cadre de l'Accord Technique d'Exécution N°2, le Bureau d'Etudes de la Division Accélérateur de l'IPNO et le groupe AT-CRI du CERN ont travaillé de concert pour mener à bien la conception des SSS (Short Straight Section) et de tous les équipements nécessaires à l'assemblage. Ce rapport a donc pour objectif de dresser, en termes d'historique, d'organisation, de résultats quantitatifs et qualitatifs et de moyens mis en ?uvre, un tableau aussi complet que possible du déroulement de cette Collaboration entre le CERN e...

Bergot, JB; Poncet, A; Rohmig, P; Roy, E; Vincent, D

2006-01-01

342

Agriculture et  

... Agriculture et échanges Des produits sensibles tels que le sucre, le lait et le riz restent souvent à lrsquo;abri de la concurrence, droits de douane prohibitifs et subventions à lrsquo;exportation aidant. Réforme des politiques agricoles La réforme des politiques agricoles doit essayer d'abaisser le niveau global du soutien aux producteurs et promouvoir des mesures qui provoquent moins de distorsions dans la production et les é changes....Soudan Soudan du Sud Sri Lanka Suisse Suriname Suède Swaziland Syrienne, République Arabe Sénégal Tadjikistan Tanzanie Tchad Thaïlande Timor-Leste (Timor Oriental) Togo Tokelau Tonga Trinité-et-Tobago Tunisie Turkménistan Turks et Caïques, Îles Turquie Tuvalu Ukraine Uruguay Vanuatu Venezuela Viêt Nam Wallis et Futuna Yémen Zambie Zimbabwe Topics list Agriculture et pêcheries Assurance et retraites Concurrence Corruption Croissance verte et développement durable Développement Développement régional, urbain et rural Echanges Economie Education Emploi Environnement ...

343

Methoxylated fatty acids reported in Rhizobium isolates arise from chemical alterations of common fatty acids upon acid-catalyzed transesterification procedures.  

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We obtained from a phospholipid extract of wild-type Rhizobium leguminosarum bv. trifolii ANU843 methoxylated fatty acids that had been previously reported as constitutive unusual Rhizobium fatty acids. The use of deuterated reagents and subsequent gas-liquid chromatography-mass spectrometry analyses showed that these methoxylated fatty acid derivatives are the products of chemical alterations of common cyclopropane-containing and unsaturated fatty acids occurring during various acid-catalyze...

Orgambide, G. G.; Reusch, R. N.; Dazzo, F. B.

1993-01-01

344

Cytochrome aa3 gene regulation in members of the family Rhizobiaceae: comparison of copper and oxygen effects in Bradyrhizobium japonicum and Rhizobium tropici.  

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Dithionite-reduced minus ferricyanide-oxidized difference spectra on membranes from Rhizobium tropici (formerly Rhizobium leguminosarum bv. phaseoli) incubated at progressively lower O2 concentrations showed only a slight concomitant decrease in A603, the alpha-peak of cytochrome aa3. In contrast to previous results on Bradyrhizobium japonicum, R. tropici showed no significant O2-mediated reduction in the level of either coxA transcription or cytochrome aa3 activity (as measured by ascorbate-...

Gabel, C.; Bittinger, M. A.; Maier, R. J.

1994-01-01

345

Role of Some Chemical Compounds on the Detoxification of Rhizobium leguminsarum biovar vicia by Some Heavy Metals  

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The toxic effect of different concentrations of some heavy metals (Cadmium, Zinc and Lead) on the growth of cultured Rhizobium leguminsarum biovar vicia was studied and their LD50 toxicity were determined. The 50% inhibition of bacterial growth was achieved by contaminating the culture with 2.1 ?M of Cadmium, 30 ?M of Zinc or 290 ?M of Lead. In attempts to counteract the toxic effect of these heavy metals, several compounds were tested to reactivate the Rhizobium g...

Sanaa Mostafa El-Deeb; Fawziah Saleh Al-Sheri

2005-01-01

346

Effectiveness of halo-tolerant, auxin producing Pseudomonas and Rhizobium strains to improve osmotic stress tolerance in mung bean (Vigna radiata L.)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Halo-tolerant, auxin producing bacteria could be used to induce salt tolerance in plants. A number of Rhizobium and auxin producing rhizobacterial strains were assessed for their ability to tolerate salt stress by conducting osmoadaptation assay. The selected strains were further screened for their [...] ability to induce osmotic stress tolerance in mung bean seedlings under salt-stressed axenic conditions in growth pouch/jar trials. Three most effective strains of Rhizobium and Pseudomonas containing ACC-deaminase were evaluated in combination, for their ability to induce osmotic stress tolerance in mung bean at original, 4, and 6 dS m-1 under axenic conditions. Results showed that sole inoculation of Rhizobium and Pseudomonas strains improved the total dry matter up to 1.4, and 1.9 fold, respectively, while the increase in salt tolerance index was improved up to 1.3 and 2.0 fold by the Rhizobium and Pseudomonas strains, respectively. However, up to 2.2 fold increase in total dry matter and salt tolerance index was observed due to combined inoculation of Rhizobium and Pseudomonas strains. So, combined application of Rhizobium and Pseudomonas strains could be explored as an effective strategy to induce osmotic stress tolerance in mung bean.

Maqshoof, Ahmad; Zahir A., Zahir; Farheen, Nazli; Fareeha, Akram; Muhammad, Arshad; Muhammad, Khalid.

347

Mechanism of acid tolerance in a rhizobium strain isolated from Pueraria lobata (Willd.) Ohwi.  

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The Rhizobium sp. strain PR389 was isolated from the root nodules of Pueraria lobata (Willd.) Ohwi, which grows in acidic (pH 4.6) yellow soil of the Jinyun Mountains of Beibei, Chongqing, China. While rhizobia generally have a pH range of 6.5-7.5 for optimum growth, strain PR389 grew in a liquid yeast extract - mannitol agar medium at pH 4.6, as well as in a pH 4.1 soil suspension, suggesting acid tolerance in this specific strain of rhizobium . However, at pH 4.6, the lag phase before vigorous growth was 40 h compared with 4 h under neutral conditions (pH 7.0). For PR389, the generation time after the lag phase remained the same at different pH levels despite the different durations of the lag phase. Except in the pH 4.4 treatment, the pH of the culturing media increased from 4.6, 4.8, 5.0, and 5.5 to neutral and slightly alkaline after 70 h of culture. Chloramphenicol was added to determine if protein production was involved in the increasing pH process. Chloramphenicol significantly inhibited PR389 growth under acid stress but had little effect under neutral conditions. Proton flux measured during a short acid shock (pH 3.8) revealed that this strain has an intrinsic ability to prevent H(+) from entering cells when compared with acid-sensitive rhizobia. We propose that the mechanism for acid tolerance in PR389 involves both intracellular and extracellular processes. When the extracellular pH is lower than pH 4.4, the cell membrane blocks hydrogen from entering the cell. When the pH exceeds 4.4, the rhizobium strain has the ability to raise the extracellular pH, thereby, potentially decreasing the toxicity of aluminum in acid soil. PMID:21635219

Lei, Zhang; Jian-ping, Gu; Shi-qing, Wei; Ze-yang, Zhou; Chao, Zhang; Yongxiong, Yu

2011-06-01

348

Efeito residual da vinhaça na população autóctone de Rhizobium do solo Residual effects of sugar cane vinasse on indigenous Rhizobia  

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Full Text Available A adição de vinhaça na cultura canavieira tem sido praticada em áreas próximas às usinas de cana. Seria de interesse a avaliação do efeito da vinhaça no Rhizobium presente no solo (autóctone, uma vez que leguminosas têm sido indicadas para cultivo intercalar com a cana. Um experimento foi conduzido em casa de vegetação, com o objetivo de verificar a influência da aplicação contínua, durante três anos, de concentrações crescentes de vinhaça (0, 100 e 1.000 m³/ha/ano, com intervalos de seis meses entre aplicações, na população autóctone de Rhizobium que nodula amendoim, soja, feijão e crotalária. Em cada cultura, foram usados controle com solo sem adição da vinhaça e um tratamento inoculado com uma estirpe de Rhizobium de conhecida eficiência, recomendada para a cultura. Uma análise do efeito de uma dose adicional de 1,5 ppm do herbicida 2,4-D no tratamento com 100 m³/ha/ano foi também efetuada. Apesar de os resultados serem variados entre as culturas, ocorreram efeitos da vinhaça sobre a população de Rhizobium, causando aumentos de nodulação na crotalária e diminuição no amendoim. Não foram observados efeitos na nodulação do feijoeiro em nenhum dos tratamentos com a vinhaça, nem na soja, que nodulou somente com a dose mais elevada, sugerindo que o Rhizobium japonicum no solo estudado estava presente em baixo número. O tratamento com herbicida mostrou tendência de favorecer a nodulação e, conseqüentemente, a fixação biológica de N2, medida através do N na planta.The addition of vinasse on sugar cane plantations nearby alcohol fermentation plants is a common practice. Legumes are recommended to be intercropped with sugar cane. A greenhouse experiment was carried out with the objective of verifying the influence of continuous application of vinasse (0; 100 and 1000 m³/ha/year at six month interval during three years on soil rhizobia which nodulate peanuts, soybeans, dry-beans and crotalaria. Controls without vinasse and with efficient Rhizobium sp. strain were maintained. The effect of 2,4 D application on the 100 m³ vinasse/ha treatment was also studied. Although results were variable and dependent on crop, the addition of vinasse influenced the rhizobia population, causing for instance, reductions on nodulation of peanuts and increases on that of crotalaria; no effects were observed either on drybeans or soybeans. Indigenous population of soybean Rhizobiun was inexpressive. The herbicide treatment showed tendency to favour nodulation and consequently N2 fixation.

Eli Sidney Lopes

1986-01-01

349

Evaluation of the biotechnological potential of Rhizobium tropici strains for exopolysaccharide production.  

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Rhizobium tropici, a member of the Rhizobiaceae family, has the ability to synthesize and secrete extracellular polysaccharides (EPS). Rhizobial EPS have attracted much attention from the scientific and industrial communities. Rhizobial isolates and R. tropici mutants that produced higher levels of EPS than the wild-type strain SEMIA4080 were used in the present study. The results suggested a heteropolymer structure for these EPS composed by glucose and galactose as prevailing monomer unit. All EPS samples exhibited a typical non-Newtonian and pseudoplastic fluid flow, and the aqueous solutions apparent viscosities increased in a concentration-dependent manner. These results serve as a foundation for further studies aimed at enhancing interest in the application of the MUTZC3, JAB1 and JAB6 strains with high EPS production and viscosity can be exploited for the large-scale commercial production of Rhizobial polysaccharides. PMID:25037342

Castellane, Tereza Cristina Luque; Lemos, Manoel Victor Franco; Lemos, Eliana Gertrudes de Macedo

2014-10-13

350

The morphogenesis of lupine root nodules during infection by Rhizobium lupini  

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Full Text Available The development of root nodules in Lupinus luteus infected by Rhizobium lupini was studied using cytological methods. The results obtained from examination of material sampled 6, 9, 13, 15, 20, 29 and 60 days after infection are given. The successive stages of development are described and the cytological characteristics of the tissue are presented. The mitotic divisions of the root cortex parenchyma cells, which initiated the formation of the nodule primordium, were accompanied by structural changes in the root hairs and divisions in the root pericycle. The development of the nodule was associated with the activity of the lateral meristems, which encompass both the infected cells and cells not containing bacteroids Characteristics of bacteria found in the symplast and apoplast of the bacteroid tissue are given.

W?adys?aw Golinowski

1987-12-01

351

Evaluation of active versus passive uptake of metabolites by Rhizobium japonicum bacteroids.  

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Rhizobium japonicum bacteroids were isolated anaerobically from soybean [Glycine max (L.) Merr] nodules. The bacteroids, which were capable of acetylene reduction and respiration, were used to study the uptake of metabolites by a method which permits correction for nonspecific adsorption of metabolites and estimation of total cell volume. These determinations permit active uptake to be assessed from metabolite accumulation against a concentration gradient. Succinate, malate, alpha-ketoglutarate, and glutamate were absorbed via an active mechanism. Plots of 1/V versus 1/[S] for succinate and malate indicated the presence of two uptake components: a saturable and presumably active or carrier-mediated component and a nonsaturable and presumably passive component. The uptake of glucose, malonate, D-pinitol, myo-inositol, and glucose 6-phosphate was slow and not active.

Reibach, P H; Streeter, J G

1984-01-01

352

Phenotypic tests in Rhizobium species description: an opinion and (a sympatric speciation) hypothesis.  

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Rhizobia seem to have large degradative and metabolic capabilities that allow them to grow on diverse soil and rhizospheric substances, many of which are still unknown. Rhizobial genome sequences encode numerous transporters for unknown substrates, and transcriptomic studies have revealed genes with unknown functions that are highly expressed in roots or rhizospheres. It is proposed here that some of these unknown-function genes may have roles in the assimilation of root or soil substances and that rhizobial speciation avoids nutrient competition. Phenotypic tests, as currently performed in taxonomy (mainly for carbon and nitrogen usage), seem to underestimate rhizobial catabolic capabilities and the differences among species. Furthermore, considering that many Rhizobium transporter and catabolism genes are plasmid-borne, the value of phenotypic results in taxonomic studies is questionable. Genomotaxonomy could soon become a robust basis for proposing novel rhizobial species. PMID:23415482

Ormeño-Orrillo, Ernesto; Martínez-Romero, Esperanza

2013-05-01

353

Isolation and Identification of Rhizobium Bacteriophages in Guilan and Isfahan Provinces, Iran  

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Full Text Available Rhizobia are one of the most important nitrogen fixing bacteria which interact specifically with legume species and induce formation of root nodules. Selective elimination of rhizobia is induced by rhizobiophages in soil. Bacteriophages can also be used for phage typing in epidemiological studies. Rhizobia were isolated from root nodules of Cicer arietinum L., Phaseolus vulgaris L. and Trigonella foenum-graecum L. plants grown in Jir-Gavabar of Roudsar and 3 areas of Isfahan. Four rhizobiophages were isolated from the same soils and purified. Morphology of the phages were studied by electron microscopy. Based on morphological features, the phages appear to be members of Myoviridae, Siphoviridae and Microviridae families. It was found for the first time that phages rather than siphoviridae are also able to infect Rhizobium leguminosarum bv. viciae ( Cicer arietinum L..

2008-01-01

354

Physiology of behavioral mutants of Rhizobium meliloti: evidence for a dual chemotaxis pathway.  

Science.gov (United States)

Wild-type and nonchemotactic mutant strains of Rhizobium meliloti were tested for attraction to localized sites on alfalfa roots and for attraction to numerous small molecules, including sugars, amino acids, and two fractions derived from alfalfa root extracts. Four strains (carrying mutations che-6, che-11, che-12, and che-26) lost all responses and were classified as generally nonchemotactic mutants. One strain (carrying mutation che-7) lost responses to a group of structurally unrelated amino acids but retained all other responses and was classified as a putative sensory transducer mutant. Two strains (carrying mutations che-1 and che-3) lost responses to all the amino acids and sugars tested but retained normal responses to localized sites on roots and to the root fractions. These two mutant strains could not be classified according to the generally accepted model for a sensory pathway, derived from studies of enteric bacteria, and provided evidence for a dual chemotaxis pathway in R. meliloti. Images

Bergman, K; Gulash-Hoffee, M; Hovestadt, R E; Larosiliere, R C; Ronco, P G; Su, L

1988-01-01

355

Physiology of behavioral mutants of Rhizobium meliloti: evidence for a dual chemotaxis pathway.  

Science.gov (United States)

Wild-type and nonchemotactic mutant strains of Rhizobium meliloti were tested for attraction to localized sites on alfalfa roots and for attraction to numerous small molecules, including sugars, amino acids, and two fractions derived from alfalfa root extracts. Four strains (carrying mutations che-6, che-11, che-12, and che-26) lost all responses and were classified as generally nonchemotactic mutants. One strain (carrying mutation che-7) lost responses to a group of structurally unrelated amino acids but retained all other responses and was classified as a putative sensory transducer mutant. Two strains (carrying mutations che-1 and che-3) lost responses to all the amino acids and sugars tested but retained normal responses to localized sites on roots and to the root fractions. These two mutant strains could not be classified according to the generally accepted model for a sensory pathway, derived from studies of enteric bacteria, and provided evidence for a dual chemotaxis pathway in R. meliloti. PMID:3384809

Bergman, K; Gulash-Hoffee, M; Hovestadt, R E; Larosiliere, R C; Ronco, P G; Su, L

1988-07-01

356

Rhizobium-initiated rice growth inhibition caused by nitric oxide accumulation.  

Science.gov (United States)

Isolates of Rhizobium leguminosarum bv. trifolii (the clover root-nodule endosymbiont) from the Nile River delta have been found to infect rice roots and colonize the intercellular spaces of the rice roots. Some of these isolates inhibit rice seedling growth but one in particular, R4, has been found in rice roots which develop and grow normally. We present evidence that the induced growth inhibition is due to a toxic accumulation of nitric oxide (NO), from the reduction of nitrate, and suggest that the reason that R4 does not inhibit rice root growth is because it is capable of completing the reduction of NO through to nitrogen gas. Thus, strain R4 is a candidate for engineering into a future biological nitrogen fixation system within these roots. PMID:17378431

Perrine-Walker, Francine M; Gartner, Elena; Hocart, Charles H; Becker, Anke; Rolfe, Barry G

2007-03-01

357

Inducing effect of plant cells on nitrogenase activity by Spirillum and Rhizobium in vitro.  

Science.gov (United States)

Eleven different plant cell tissue cultures of both legume and non-legume origin have been grown in direct association, and in separate but close proximal association with both Spirillum lipoferum and Rhizobium sp. 32H1. Basic similarities were found in the nutritional requirement for the induction of nitrogenase activity (C2H2) in both organisms. In the absence of plant cell cultures both organisms need to be provided with a pentose sugar and a tricarboxylic acid to induce high levels of nitrogen-fixing activity. Plant cell callus tissue appears only capable of supplying the tricarboxylic acid to induce high levels of nitrogen-fixing activity. Plant cell callus tissue appears only capable of supplying the tricarboxylic acids needed but not the sugar component. The plant tissue, however, seems able to activate certain carbohydrates, which in themselves are incapable of substituting for the pentose additive. PMID:647472

Child, J J; Kurz, W G

1978-02-01

358

Localized Changes in Flavonoid Biosynthesis in Roots of Lotus pedunculatus after Infection by Rhizobium loti.  

Science.gov (United States)

Two-dimensional paper chromatography in four solvent systems, high-sensitivity spray reagents, and UV absorption spectroscopy were used to separate and characterize flavonoids and isoflavonoids in roots and root nodules of 20-d-old Lotus pedunculatus Cav. Seedlings were grown either under sterile conditions or after inoculation with Fix(+) or Fix(-) strains of Rhizobium loti. Flavonoids rather than isoflavonoids predominated in all tissues. Flavonoid profiles in sterile and denodulated root tissues were remarkably similar, both qualitatively and quantitatively. At least 14 partially purified flavonoid aglycones and conjugates were found in root extracts; denodulated root tissues contained no compounds that were not also present in sterile roots. Fix(+) rhizobia were responsible for major postinfection shifts in plant flavonoid biosynthesis at the sites of nodule morphogenesis. Polymeric flavolans were absent from Fix(+) nodules but present in all root tissues and in Fix(-) nodules. Catechin was detected only in Fix(+) nodules. PMID:16652981

Cooper, J E; Rao, J R

1992-09-01

359

Localized Changes in Flavonoid Biosynthesis in Roots of Lotus pedunculatus after Infection by Rhizobium loti1  

Science.gov (United States)

Two-dimensional paper chromatography in four solvent systems, high-sensitivity spray reagents, and UV absorption spectroscopy were used to separate and characterize flavonoids and isoflavonoids in roots and root nodules of 20-d-old Lotus pedunculatus Cav. Seedlings were grown either under sterile conditions or after inoculation with Fix+ or Fix? strains of Rhizobium loti. Flavonoids rather than isoflavonoids predominated in all tissues. Flavonoid profiles in sterile and denodulated root tissues were remarkably similar, both qualitatively and quantitatively. At least 14 partially purified flavonoid aglycones and conjugates were found in root extracts; denodulated root tissues contained no compounds that were not also present in sterile roots. Fix+ rhizobia were responsible for major postinfection shifts in plant flavonoid biosynthesis at the sites of nodule morphogenesis. Polymeric flavolans were absent from Fix+ nodules but present in all root tissues and in Fix? nodules. Catechin was detected only in Fix+ nodules.

Cooper, James E.; Rao, J. Raghavendra

1992-01-01

360

Effect of Rhizobium inoculation of seeds and foliar fertilization on productivity of Pisum sativum L.  

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Full Text Available Pea (Pisum sativum L. is the second most important grain legume crop in the world which has a wide array of uses for human food and fodder. One of the major factors that determines the use of field pea is the yield potential of cultivars. Presently, pre-sowing inoculation of pea seeds and foliar application of microelement fertilizers are prospective solutions and may be reasonable agrotechnical options. This research was undertaken because of the potentially high productivity of the 'afila' morphotype in good wheat complex soils. The aim of the study was to determine the effect of vaccination with Rhizobium and foliar micronutrient fertilization on yield of the afila pea variety. The research was based on a two-year (2009–2010 controlled field experiment, conducted in four replicates and carried out on the experimental field of the Bayer company located in Modzurów, Silesian region. experimental field soil was Umbrisol – slightly degraded chernozem, formed from loess. Nitragina inoculant, as a source of symbiotic bacteria, was applied before sowing seeds. Green area index (GAI of the canopy, photosynthetically active radiation (PAR, and normalized difference vegetation index (NDVI were determined at characteristic growth stages. The presented results of this study on symbiotic nitrogen fixation by leguminous plants show that the combined application of Nitragina and Photrel was the best combination for productivity. Remote measurements of the pea canopy indexes indicated the formation of the optimum leaf area which effectively used photosynthetically active radiation. The use of Nitragina as a donor of effective Rhizobium for pea plants resulted in slightly higher GAI values and the optimization of PAR and NDVI. It is not recommended to use foliar fertilizers or Nitragina separately due to the slowing of pea productivity.

Tadeusz Zaj?c

2013-07-01

 
 
 
 
361

Rhizobium leguminosarum hupE encodes a nickel transporter required for hydrogenase activity.  

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Synthesis of the hydrogen uptake (Hup) system in Rhizobium leguminosarum bv. viciae requires the function of an 18-gene cluster (hupSLCDEFGHIJK-hypABFCDEX). Among them, the hupE gene encodes a protein showing six transmembrane domains for which a potential role as a nickel permease has been proposed. In this paper, we further characterize the nickel transport capacity of HupE and that of the translated product of hupE2, a hydrogenase-unlinked gene identified in the R. leguminosarum genome. HupE2 is a potential membrane protein that shows 48% amino acid sequence identity with HupE. Expression of both genes in the Escherichia coli nikABCDE mutant strain HYD723 restored hydrogenase activity and nickel transport. However, nickel transport assays revealed that HupE and HupE2 displayed different levels of nickel uptake. Site-directed mutagenesis of histidine residues in HupE revealed two motifs (HX(5)DH and FHGX[AV]HGXE) that are required for HupE functionality. An R. leguminosarum double mutant, SPF22A (hupE hupE2), exhibited reduced levels of hydrogenase activity in free-living cells, and this phenotype was complemented by nickel supplementation. Low levels of symbiotic hydrogenase activity were also observed in SPF22A bacteroid cells from lentil (Lens culinaris L.) root nodules but not in pea (Pisum sativum L.) bacteroids. Moreover, heterologous expression of the R. leguminosarum hup system in bacteroid cells of Rhizobium tropici and Mesorhizobium loti displayed reduced levels of hydrogen uptake in the absence of hupE. These data support the role of R. leguminosarum HupE as a nickel permease required for hydrogen uptake under both free-living and symbiotic conditions. PMID:20023036

Brito, Belén; Prieto, Rosa-Isabel; Cabrera, Ezequiel; Mandrand-Berthelot, Marie-Andrée; Imperial, Juan; Ruiz-Argüeso, Tomás; Palacios, José-Manuel

2010-02-01

362

Rhizobium leguminosarum hupE Encodes a Nickel Transporter Required for Hydrogenase Activity?  

Science.gov (United States)

Synthesis of the hydrogen uptake (Hup) system in Rhizobium leguminosarum bv. viciae requires the function of an 18-gene cluster (hupSLCDEFGHIJK-hypABFCDEX). Among them, the hupE gene encodes a protein showing six transmembrane domains for which a potential role as a nickel permease has been proposed. In this paper, we further characterize the nickel transport capacity of HupE and that of the translated product of hupE2, a hydrogenase-unlinked gene identified in the R. leguminosarum genome. HupE2 is a potential membrane protein that shows 48% amino acid sequence identity with HupE. Expression of both genes in the Escherichia coli nikABCDE mutant strain HYD723 restored hydrogenase activity and nickel transport. However, nickel transport assays revealed that HupE and HupE2 displayed different levels of nickel uptake. Site-directed mutagenesis of histidine residues in HupE revealed two motifs (HX5DH and FHGX[AV]HGXE) that are required for HupE functionality. An R. leguminosarum double mutant, SPF22A (hupE hupE2), exhibited reduced levels of hydrogenase activity in free-living cells, and this phenotype was complemented by nickel supplementation. Low levels of symbiotic hydrogenase activity were also observed in SPF22A bacteroid cells from lentil (Lens culinaris L.) root nodules but not in pea (Pisum sativum L.) bacteroids. Moreover, heterologous expression of the R. leguminosarum hup system in bacteroid cells of Rhizobium tropici and Mesorhizobium loti displayed reduced levels of hydrogen uptake in the absence of hupE. These data support the role of R. leguminosarum HupE as a nickel permease required for hydrogen uptake under both free-living and symbiotic conditions.

Brito, Belen; Prieto, Rosa-Isabel; Cabrera, Ezequiel; Mandrand-Berthelot, Marie-Andree; Imperial, Juan; Ruiz-Argueso, Tomas; Palacios, Jose-Manuel

2010-01-01

363

FORAGE PRODUCTIVITY OF ARBILA (Phaseolus lunatus AT VARIOUS LEVELS OF RHIZOBIUM INOCULANTS AND HARVESTING TIMES  

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Full Text Available The study was conducted to evaluate forage productivity of arbila (Phaseolus lunatus as the ruminant feed at various levels of rhizobium inoculants and harvesting times, was designed following completely randomized design of factorial pattern with two factors. The first factor was the level of inoculums (I i.e. I1 (without inoculum, I2 (5 g/kg seed, I3 (10 g/kg seed, and I4 (15 g/kg seed. The second factor was harvesting time (U i.e. U1 (60 days, U2 (80 days, U3 (100 days with 4 replications. The variables were N uptake, production of dry matter (DM and organic matter (OM, and percentage of OM, crude protein (CP, crude fiber (CF, nitrogen free extract (NFE, extract ether (EE and ash of arbila forage (based on DM. The results showed that inoculant treatment at the rate of 15 g/kg seed produced the highest percentage of effective nodules (98.72%, and in combination with harvesting age at 100 days each polybag of plant was able to absorb the higest amount of N (688. 10 g with production of DM 273.81 g, OM production 263.96 g and nutrients content based on DM of about 91.14% OM, 33.52% CF, 34.76%, 5.75% EE, 09.37% ash, and 16.16% CP. From the study, it can be concluded that arbila plants inoculated specific rhizobium Phaseolus vulgaris at the rate of 15 g/kg seed and harvested at 100 days yielded the best forage as feed.

B. B. Koten

2012-12-01

364

Variability of isolated colonies in bean nodulating Rhizobium strains before and after exposure to high temperature Variabilidade de colônias isoladas de estirpes de Rhizobium efetivas na nodulação do feijoeiro, antes de após exposição temperatura elevada  

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Irregular response to bean plants to Rhizobium inoculation has been attributed to among other factors, low competitive ability, low N2 fixation efficiency and genetic instability of the symbiont. This genetic instability caused by high rates of genomic rearrangements and/or plasmid deletions can be accentuated by high temperatures. This fact may limit the utilization of these strains as inoculants, especially in tropical soils. In this study, the variability of isolated colonies derived from ...

Rui Raposeiras; Pinto, Patri?cia P.; Passos, Raul V. M.; Lucy Seldin; Edilson Paiva; Rita Scotti, M.; Sa?, Nadja M. H.

2002-01-01

365

Interacción de Tsukamurella paurometabola C-924 con Rhizobium leguminosarum biovar phaseoli CFH en el cultivo de frijol / Interaction among Tsukamurella paurometabola C-924 and Rhizobium leguminosarum biovar phaseoli CFH in bean plants  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish En el estudio se evaluaron, mediante análisis de los parámetros fenológicos de las plantas, la interacción de Tsukamurella paurometabola C-924 con Rhizobium leguminosarum biovar phaseoli CFH en el cultivo de frijol. Se emplearon cuatro tratamientos: plantas sin inocular (control), inoculadas con T. [...] paurometabola C-924, inoculadas con R. leguminosarum biovar phaseoli CFH e inoculadas con ambas cepas. Se observaron diferencias significativas (P Abstract in english The experiment was carried out to evaluate the interaction between Tsukamurella paurometabola C-924 and Rhizobium leguminosarum biovar phaseoli CFH in bean plants. Treatments consisted of non-inoculated plants (control), plants inoculated with T. paurometabola C-924, inoculated with R. leguminosarum [...] biovar phaseoli CFH and inoculated with both strains. The application of the microorganisms single or in coinoculation improved the germination of seeds. T. paurometabola C-924 did not enhanced Rhizobium nodulation. However, no significant differences were found among treatments for shoot height and diameter. There was an increase in number of leaves in the plants inoculated with T. paurometabola C-924. We concluded that the interaction between T. paurometabola C-924 and R. leguminosarum biovar phaseoli CFH improved the number of leaves and the germination of seeds and even though T. paurometabola C-924 did not enhance nodulation, this fact did not affect the plants growth.

Marieta, Marín Bruzos; Jesús, Mena Campos; Pavel, Chaveli Chávez; Rolando, Morán Valdivia; Eulogio, Pimentel Vázquez.

366

Presença e eficiência de Rhizobium Japonicum em solos cultivados ou não com soja, no estado deSão Paulo Presence and efficiency of Rhizobium Japonicum in soils previously cultivated and never cultivated with soybeans  

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Full Text Available Foi conduzido um ensaio em solução nutritiva sem nitrogênio, com condições assépticas, usando-se como inoculantes para as plantas amostras de solos LR e LB coletadas em locais já cultivados e não com soja, com o objetivo de verificar a presença de Rhizobium capaz de nodular o cultivar santa-rosa. Verificou-se que solos ainda não cultivados com a leguminosa são desprovidos de Rhizobium japonicum, e também que essa bactéria é encontrada em solos previamente cultivados, fixando nitrogênio em quantidades equivalentes à de uma estirpe selecionada.An experiment was carried out in Leonard jars using Latosolic B Terra Roxa and Dark Red Latosol soil samples as inoculum to detect the presence and efficiency of rhizobia able to nodulate cultivar Santa-Rosa of soybean (Glycine max. (L Merrill. Results have shown that no rhizobia were present in those soils. Rhizobium japonicum with efficiency comparable to a selected strain survived in the same soils, when they were previously cropped with inoculated soybeans.

Eli Sidney Lopes

1976-07-01

367

Presença e eficiência de Rhizobium Japonicum em solos cultivados ou não com soja, no estado deSão Paulo / Presence and efficiency of Rhizobium Japonicum in soils previously cultivated and never cultivated with soybeans  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Foi conduzido um ensaio em solução nutritiva sem nitrogênio, com condições assépticas, usando-se como inoculantes para as plantas amostras de solos LR e LB coletadas em locais já cultivados e não com soja, com o objetivo de verificar a presença de Rhizobium capaz de nodular o cultivar santa-rosa. Ve [...] rificou-se que solos ainda não cultivados com a leguminosa são desprovidos de Rhizobium japonicum, e também que essa bactéria é encontrada em solos previamente cultivados, fixando nitrogênio em quantidades equivalentes à de uma estirpe selecionada. Abstract in english An experiment was carried out in Leonard jars using Latosolic B Terra Roxa and Dark Red Latosol soil samples as inoculum to detect the presence and efficiency of rhizobia able to nodulate cultivar Santa-Rosa of soybean (Glycine max. (L) Merrill). Results have shown that no rhizobia were present in t [...] hose soils. Rhizobium japonicum with efficiency comparable to a selected strain survived in the same soils, when they were previously cropped with inoculated soybeans.

Eli Sidney, Lopes; Antônio Roberto, Giardini; Romeu A. S., Kiihl.

368

Dual inoculation with an Aarbuscular Mycorrhizal fungus and Rhizobium to facilitate the growth of alfalfa on coal mine substrates  

Energy Technology Data Exchange (ETDEWEB)

A pot experiment was conducted to investigate the effects of Glomus mosseae and Rhizobium on Medicago sativa grown on three types of coal mine substrates, namely a mixture of coal wastes and sands (CS), coal wastes and fly ash (CF), and fly ash (FA). Inoculation with Rhizobium alone did not result in any growth response but G. mosseae alone displayed a significant effect on plant growth. G. mosseae markedly increased the survival rate of M. sativa in CS substrate. In CF and FA substrates the respective oven dry weights of M. sativa inoculated with G. mosseae were 1.8 and 5.1 times higher than those without inoculation. Based on nitrogen (N), phosphorus (P) and potassium (K) uptake and legume growth, the results also show that dual inoculation in CS and CF substrates elicited a synergistic effect. This indicates that inoculation with arbuscular mycorrhizal (AM) fungi may be a promising approach for revegetation of coal mine substrates.

Wu, F.Y.; Bi, Y.L.; Wong, M.H. [China University of Mining & Technology, Beijing (China)

2009-07-01

369

Tolerance Of Several Rhizobium Strain/Isolate To A1 and Their Interaction With Several Soybean Mutants  

International Nuclear Information System (INIS)

Research activities to study the interaction of several soybean mutant and rhizobium strain/isalates were carried out. The first experiment to be involved screening of nine strain/isolates for tolerance to A1 acid stress. Five strains/isolates were considered tolerance. Further experiment with three strains/isolates with difference A1 concentrations, showed that the isolate no. 06 had the highest growth rate followed by isolate 09 and TAL 102. Experiment on interaction of five soybean mutant/varieties with those strains/isolates were carried out in nutrient culture. Mutant no. 21 and 43 showed better growth in solution containing 50 uM A1. Good nodulation occured in mutant no. 23 inoculated with Rhizobium isolate no. 06. This good symbiotic association should be studied further at higher A1 concentration. (authors). 14 refs, 6 tabs

1989-01-01

370

Synthesis and adsorption properties of titanosilicates ETS-4 and ETS-10 from fly ash  

International Nuclear Information System (INIS)

Highlights: ? Titanosilicates (ETS-4 and ETS-10) have been synthesized from waste fly ash. ? These materials showed similar properties to those prepared from traditional starting materials. ? The supernatant liquid after product formation (ETS-4) can be recycled and the final by-product is NaCl. ? These materials can be used for CO2/CH4 and N2 adsorption. - Abstract: ETS-4 and ETS-10 titanosilicates were prepared from fly ash and anatase, as silica and titanium sources respectively, via a hydrothermal procedure for the first time. The fusion of fly ash by alkali was carried out at a relatively low temperature and the use potassium fluoride salt was avoided in the synthesis of ETS. The by-product of this process is mainly NaCl, which is a useful source material for industry. The energy efficiency and yield of the synthesis process was improved by directly recycling the final filtrate after recovering the product viz ETS-4. All the ETS materials were characterized in terms of structural morphology, thermal stability and surface/pore properties. The properties of ETS-4 prepared from fly ash by the filtrate recycling method were comparable to that from commercial sources. The results show that ETS type materials can be prepared from cheaper resources, with good purity, comparable physico-chemical properties as well as excellent adsorption properties with lower environmental impact.

2011-11-15

371

Synthesis and adsorption properties of titanosilicates ETS-4 and ETS-10 from fly ash  

Energy Technology Data Exchange (ETDEWEB)

Highlights: {yields} Titanosilicates (ETS-4 and ETS-10) have been synthesized from waste fly ash. {yields} These materials showed similar properties to those prepared from traditional starting materials. {yields} The supernatant liquid after product formation (ETS-4) can be recycled and the final by-product is NaCl. {yields} These materials can be used for CO{sub 2}/CH{sub 4} and N{sub 2} adsorption. - Abstract: ETS-4 and ETS-10 titanosilicates were prepared from fly ash and anatase, as silica and titanium sources respectively, via a hydrothermal procedure for the first time. The fusion of fly ash by alkali was carried out at a relatively low temperature and the use potassium fluoride salt was avoided in the synthesis of ETS. The by-product of this process is mainly NaCl, which is a useful source material for industry. The energy efficiency and yield of the synthesis process was improved by directly recycling the final filtrate after recovering the product viz ETS-4. All the ETS materials were characterized in terms of structural morphology, thermal stability and surface/pore properties. The properties of ETS-4 prepared from fly ash by the filtrate recycling method were comparable to that from commercial sources. The results show that ETS type materials can be prepared from cheaper resources, with good purity, comparable physico-chemical properties as well as excellent adsorption properties with lower environmental impact.

Liu, Liying [School of Material and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China); Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800 (Australia); Singh, Ranjeet, E-mail: Ranjeet.Singh@monash.edu [Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800 (Australia); Li, Gang; Xiao, Penny; Webley, Paul [Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC), Department of Chemical Engineering, Monash University, Clayton, Victoria 3800 (Australia); Zhai, Yuchun [School of Material and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China)

2011-11-15

372

Impact of Salicylic Acid on Symbiotic Relations Between Peas and Rhizobium leguminosarum bv. viceae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The study was targeted at the investigation of exogenous salicylic acid (SA) impact on bacteria proliferation in vitro, rhizobia penetration in the root tissues, the SA and hydrogen peroxide (H2O2) content in the root seedlings under inoculation of pea by compatible strain Rhizobium leguminosarum bv. viceae. Depending on the concentration SA either did not affect (0.0036-0.014 mM) rhizobia proliferation or suppressed their growth (0.07-0...

Glyanko, A. K.; Makarova, L. E.; Luzova, G. B.; Mironova, N. V.; Vasilieva, G. G.

2004-01-01

373

Quantitative 1 H NMR spectroscopy analysis of the poly(3-hydroxy alkanoate) extracted from Rhizobium meliloti cells  

International Nuclear Information System (INIS)

1H NMR analysis was carried out to determine the nature and the concentration of the poly(3-hydroxyalkanoate) (PHA) accumulated by Rhizobium meliloti M5N1. The PHA was identified as being poly(3-hydroxybutyrate) (PHB). Benzene was shown to meet all the requirements of an internal reference for PHB quantification. NMR data were in good agreement with corresponding data obtained by Gas Chromatography (GC) analysis. (authors). 4 refs., 2 figs

1995-10-01

374

Phenotype profiling of Rhizobium leguminosarum bv. trifolii clover nodule isolates reveal their both versatile and specialized metabolic capabilities  

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Rhizobium leguminosarum bv. trifolii (Rlt) are soil bacteria inducing nodules on clover, where they fix nitrogen. Genome organization analyses of 22 Rlt clover nodule isolates showed that they contained 3–6 plasmids and majority of them possessed large (>1 Mb), chromid-like replicon with exception of four Rlt strains. The Biolog phenotypic profiling comprising utilization of C, N, P, and S sources and tolerance to osmolytes and pH revealed metabolic versatility of the Rlt strains. Statisti...

Mazur, Andrzej; Stasiak, Graz?yna; Wielbo, Jerzy; Koper, Piotr; Kubik-komar, Agnieszka; Skorupska, Anna

2013-01-01

375

Protein-Protein Interactions within Type III Secretion System-Dependent Pili of Rhizobium sp. Strain NGR234?  

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Pili synthesized by the type III secretion system of Rhizobium species strain NGR234 are essential for protein secretion and thus for efficient symbiosis with many legumes. Isolation and partial purification of these pili showed that they are composed of at least three proteins, NopA, NopB, and NopX. Using biochemical assays, we show here that these proteins interact directly with one another.

Saad, Maged M.; Staehelin, Christian; Broughton, William J.; Deakin, William J.

2008-01-01

376

Nucleotide Sequence and Genetic Structure of a Novel Carbaryl Hydrolase Gene (cehA) from Rhizobium sp. Strain AC100  

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Rhizobium sp. strain AC100, which is capable of degrading carbaryl (1-naphthyl-N-methylcarbamate), was isolated from soil treated with carbaryl. This bacterium hydrolyzed carbaryl to 1-naphthol and methylamine. Carbaryl hydrolase from the strain was purified to homogeneity, and its N-terminal sequence, molecular mass (82 kDa), and enzymatic properties were determined. The purified enzyme hydrolyzed 1-naphthyl acetate and 4-nitrophenyl acetate indicating that the enzyme is an esterase. We then...

Hashimoto, Masayuki; Fukui, Mitsuru; Hayano, Kouichi; Hayatsu, Masahito

2002-01-01

377

Rhizobium leguminosarum bv. viciae populations in soils with increasing heavy metal contamination: abundance, plasmid profiles, diversity and metal tolerance  

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Populations of Rhizobium leguminosarum bv. viciae were investigated from plots of a long-term sewage sludge experiment in Braunschweig, Germany, which represented a gradient of increasing metal contamination. The number of R. leguminosarum bv. viciae decreased from 105 cells g¿1 soil in uncontaminated plots to between 7 and 102 cells g¿1 soil with increasing Zn concentration (from 50 to 400 mg kg¿1). Rhizobia were isolated from nodules of Vicia hirsuta inoculated with dilutions of soil fro...

Lakzian, A.; Murphy, P.; Turner, A.; Beynon, J. L.; Giller, K. E.

2002-01-01

378

New Field Isolates of Rhizobium leguminosarum Biovar Viciae That Nodulate the Primitive Pea Cultivar Afghanistan in Addition to Modern Cultivars  

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A collection of 13 field isolates of Rhizobium leguminosarum bv. viciae that have the ability to nodulate the roots of current North American cultivars of peas as well as a “primitive” cultivar, Afghanistan, was examined. These isolates originated in diverse geographical regions of the world, which indicates that this phenotype is not restricted to isolates from any one region. When subclones of the nodulation region from one plasmid were used to examine EcoRI-fragment-length polymorphism...

1990-01-01

379

Compatibility of Rhizobial Genotypes within Natural Populations of Rhizobium leguminosarum Biovar viciae for Nodulation of Host Legumes  

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Populations of Rhizobium leguminosarum biovar viciae were sampled from two bulk soils, rhizosphere, and nodules of host legumes, fava bean (Vicia faba) and pea (Pisum sativum) grown in the same soils. Additional populations nodulating peas, fava beans, and vetches (Vicia sativa) grown in other soils and fava bean-nodulating strains from various geographic sites were also analyzed. The rhizobia were characterized by repetitive extragenomic palindromic-PCR fingerprinting and/or PCR-restriction ...

Laguerre, Gise?le; Louvrier, Philippe; Allard, Marie-reine; Amarger, Noe?lle

2003-01-01

380

Symbiotic and Genetic Diversity of Rhizobium galegae Isolates Collected from the Galega orientalis Gene Center in the Caucasus  

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This paper explores the relationship between the genetic diversity of rhizobia and the morphological diversity of their plant hosts. Rhizobium galegae strains were isolated from nodules of wild Galega orientalis and Galega officinalis in the Caucasus, the center of origin for G. orientalis. All 101 isolates were characterized by genomic amplified fragment length polymorphism fingerprinting and by PCR-restriction fragment length polymorphism (RFLP) of the rRNA intergenic spacer and of five par...

Andronov, E. E.; Terefework, Z.; Roumiantseva, M. L.; Dzyubenko, N. I.; Onichtchouk, O. P.; Kurchak, O. N.; Dresler-nurmi, A.; Young, J. P. W.; Simarov, B. V.; Lindstro?m, K.

2003-01-01

 
 
 
 
381

Analysis of the lipid moiety of lipopolysaccharide from Rhizobium tropici CIAT899: identification of 29-hydroxytriacontanoic acid.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The lipid moieties of two lipid A's isolated from the phenolic and aqueous fractions of lipopolysaccharide from Rhizobium tropici CIAT899 have been studied. Several 3-hydroxy fatty acids and two long-chain hydroxy fatty acids, 27-hydroxyoctacosanoic acid, and 29-hydroxytriacontanoic acid were identified; the ratios of these acids are the same in both lipid A's. These results can be used for chemotaxonomic purposes.

1994-01-01

382

Physical and genetic characterization of symbiotic and auxotrophic mutants of Rhizobium meliloti induced by transposon Tn5 mutagenesis.  

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We have physically and genetically characterized 20 symbiotic and 20 auxotrophic mutants of Rhizobium meliloti, the nitrogen-fixing symbiont of alfalfa (Medicago sativa), isolated by transposon Tn5 mutagenesis. A "suicide plasmid" mutagenesis procedure was used to generate TN-5-induced mutants, and both auxotrophic and symbiotic mutants were found at a frequency of 0.3% among strains containing random TN5 insertions. Two classes of symbiotic mutants were isolated: 4 of the 20 formed n...

1982-01-01

383

Attenuation of Symbiotic Effectiveness by Rhizobium meliloti SAF22 Related to the Presence of a Cryptic Plasmid  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several wild-type strains of Rhizobium meliloti isolated from alfalfa nodules exhibited different plasmid profiles, yet did not differ in growth rate in yeast-mannitol medium, utilization of 43 different carbon sources, intrinsic resistance to 14 antibiotics, or detection of 16 enzyme activities. In contrast, three measures of effectiveness in symbiotic nitrogen fixation with alfalfa (shoot length, dry weight, and nitrogen content) indicated that R. meliloti SAF22, whose plasmid profile diffe...

Velazquez, E.; Mateos, P. F.; Pedrero, P.; Dazzo, F. B.; Martinez-molina, E.

1995-01-01

384

Localization of Bacteria and Hemoglobin in Root Nodules of Parasponia andersonii Containing Both Bradyrhizobium Strains and Rhizobium leguminosarum biovar trifolii  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dual occupancy of Parasponia andersonii nodules with different Bradyrhizobium strains and Rhizobium leguminosarum biovar trifolii was frequently obtained when two strains were inoculated into plants grown aseptically in tubes. Since reisolates of Bradyrhizobium strains from dually occupied nodules acquired the ability to nodulate Trifolium repens, the spatial relationship of the two species of bacteria during nodule initiation and development was investigated and their proximity was demonstra...

Trinick, Michael J.; Goodchild, David J.; Miller, Celia

1989-01-01

385

Effects of Carrier and Temperature on Survival of Rhizobium spp. in Legume Inocula: Development of an Improved Type of Inoculant †  

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The effects of inoculant carrier, temperature, and storage period on the survival of Rhizobium strains were determined by plate count and most-probable-number analyses. Preliminary experiments showed that survival of rhizobia was affected by each of these factors and their interactions. Results of further studies indicated that six strains of rhizobia survived better at high temperatures when lyophilized and suspended in an oil carrier as compared to finely ground peat. The oil base inocula c...

1983-01-01

386

Genetic analysis of a cluster of genes required for synthesis of the calcofluor-binding exopolysaccharide of Rhizobium meliloti.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rhizobium meliloti produces an acidic, Calcofluor-binding exopolysaccharide which plays a role in nodulation of alfalfa plants by this bacterium. We constructed and mapped 102 transposon insertions in a 48-kilobase (kb) region previously shown to contain several exo genes. Mutations affecting production of the Calcofluor-binding exopolysaccharide were clustered in a 22-kb region and fell into 12 complementation groups. Strains carrying mutations in seven of the complementation groups (exoA, e...

Long, S.; Reed, J. W.; Himawan, J.; Walker, G. C.

1988-01-01

387

Role of Rhizobium endoglucanase CelC2 in cellulose biosynthesis and biofilm formation on plant roots and abiotic surfaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background The synthesis of cellulose is among the most important but poorly understood biochemical processes, especially in bacteria, due to its complexity and high degree of regulation. In this study, we analyzed both the production of cellulose by all known members of the Rhizobiaceae and the diversity of Rhizobium celABC operon predicted to be involved in cellulose biosynthesis. We also investigated the involvement in cellulose production and biofilm formation of celC gene encodi...

Robledo, M.; Rivera, L.; Jime?nez-zurdo, Jose I.; Rivas, R.; Dazzo, F.; Vela?zquez, E.; Marti?nez-molina, E.; Hirsch, Ann M.; Mateos, Pedro F.

2012-01-01

388

Glucomannan-Mediated Attachment of Rhizobium leguminosarum to Pea Root Hairs Is Required for Competitive Nodule Infection?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Rhizobium leguminosarum biovar viciae genome contains several genes predicted to determine surface polysaccharides. Mutants predicted to affect the initial steps of polysaccharide synthesis were identified and characterized. In addition to the known cellulose (cel) and acidic exopolysaccharide (EPS) (pss) genes, we mutated three other loci; one of these loci (gmsA) determines glucomannan synthesis and one (gelA) determines a gel-forming polysaccharide, but the role of the other locus (an ...

2008-01-01

389

Modulation of rosR Expression and Exopolysaccharide Production in Rhizobium leguminosarum bv. trifolii by Phosphate and Clover Root Exudates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The acidic exopolysaccharide (EPS) secreted in large amounts by the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum bv. trifolii is required for the establishment of an effective symbiosis with the host plant Trifolium spp. EPS biosynthesis in rhizobia is a very complex process regulated at both transcriptional and post-transcriptional levels and influenced by various nutritional and environmental conditions. The R. leguminosarum bv. trifolii rosR gene encodes a transcriptional re...

Monika Janczarek; Anna Skorupska

2011-01-01

390

Correlation between Map Position and Phenotype of CTI Mutants in the C Cistron of RHIZOBIUM MELILOTI Phage 16–3  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nine temperature-sensitive clear mutations (Cti) in the C cistron (coding for the repressor protein) of Rhizobium meliloti temperate phage 16–3 were characterized according to the inductive temperature, the immunity of cells lysogenic for these mutant phages to superinfection by homoimmune weak virulent mutants, the phenotype of double-ti mutants and interallelic complementation. The results indicate that mutations of similar phenotypic expression are clustered on the genetic map. Furthermo...

Duda?s, Brigitta; Orosz, La?szlo?

1980-01-01

391

Nodulation inhibition by Rhizobium leguminosarum multicopy nodABC genes and analysis of early stages of plant infection.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During analysis of early events in the infection and nodulation of Vicia hirsuta roots inoculated with normal and mutant strains of Rhizobium leguminosarum and strains containing cloned nodulation (nod) genes, a number of novel observations were made. (i) Alternating zones of curled and straight root hairs were seen on roots of V. hirsuta inoculated with the wild-type strain of R. leguminosarum. This phasing of root hair curling was not seen if plants were grown under continuous light or cont...

Knight, C. D.; Rossen, L.; Robertson, J. G.; Wells, B.; Downie, J. A.

1986-01-01

392

Reexamination of the presence and linkage of 3-hydroxybutyryl substituents in the acidic capsular polysaccharide of Rhizobium trifolii 0403.  

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We resolved previous conflicting results concerning the presence of 3-hydroxybutyryl substituents on the extracellular acidic polysaccharide from Rhizobium trifolii 0403. These substituents were indeed present in the polysaccharide and in the oligosaccharide fragments obtained by hydrogen fluoride solvolysis of the extracellular and capsular polysaccharides of the bacteria grown on plates. The 3-hydroxybutyrate substituent could be removed from the polysaccharide by 10 mM sodium deuteroxide w...

1987-01-01

393

VARIATION IN RHIZOBIUM GROWTH DUE TO SEED AND ROOT EXUDATES RELEASED FROM GAMMA IRRADIATED GLYCINE MAX SEEDS  

International Nuclear Information System (INIS)

In this study, seeds of Glycine max Giza 122 were irradiated with gamma rays from 60Co source at various doses (10 to 200 Gy), sterilized and soaked into an aerated solution of CaSO4 (1 mmol and pH 6.5). The capacities of the released seed exudates (SEs) and root exudates (REs) to promote Rhizobium leguminosarum growth were investigated as well as biochemical analysis of the exudates was carried out. SE of both control and gamma irradiated seeds resulted in a higher Rhizobium population and polysaccharide production than RE. Relative to control, the highly effective doses in Rhizobium growth and polysaccharide production were 25 and 200 Gy; the former was a promoter while the later was an inhibitor. HPLC analysis of soluble carbohydrates revealed the presence of glucose (Glu), rhamnose (Rha) and fructose (Fru) in the SE and RE. Protein content in SE was lower than that in RE; the highest values were due to 10 Gy and 25 Gy in SE and RE, respectively. Free amino acids content in SE was increased up to 25 Gy then decreased while RE was increased by increasing gamma doses from 10 to 200 Gy

2008-01-01

394

Quantitative analysis of the naringenin-inducible proteome in Rhizobium leguminosarum by isobaric tagging and mass spectrometry.  

Science.gov (United States)

The rhizobium-legume interaction is a critical cornerstone of crop productivity and environmental sustainability. Its potential improvement relies on elucidation of the complex molecular dialogue between its two partners. In the present study, the proteomic patterns of gnotobiotic cultures of Rhizobium leguminosarum bv. viciae 3841 grown for 6 h in presence or absence of the nod gene-inducing plant flavonoid naringenin (10 ?M) were analyzed using the iTRAQ approach. A total of 1334 proteins were identified corresponding to 18.67% of the protein-coding genes annotated in the sequenced genome of bv. viciae 3841. The abundance levels of 47 proteins were increased upon naringenin treatment showing fold change ratios ranging from 1.5 to 25 in two biological replicates. Besides the nod units, naringenin enhanced the expression of a number of other genes, many of which organized in operons, including ?(1-2) glucan production and secretion, succinoglycan export, the RopA outer membrane protein with homology to an oligogalacturonide-specific porin motif, other enzymes for carbohydrate and amino acid metabolism, and proteins involved in the translation machinery. Data were validated at the transcriptional and phenotypic levels by RT-PCR and an assay of secreted sugars in culture supernatants, respectively. The current approach provides not only a high-resolution analysis of the prokaryotic proteome but also unravels the rhizobium molecular dialogue with legumes by detecting the enhanced expression of several symbiosis-associated proteins, whose flavonoid-dependency had not yet been reported. PMID:23580418

Tolin, Serena; Arrigoni, Giorgio; Moscatiello, Roberto; Masi, Antonio; Navazio, Lorella; Sablok, Gaurav; Squartini, Andrea

2013-06-01

395

INTERACCIÓN RHIZOBIUM LEGUMINOSARUM BV TRIFOLII Y HONGOS MICORRÍCICOS EN UN ANDISOL CON DIFERENTES NIVELES DE SATURACIÓN DE ALUMINIO / INTERACTION OF RHIZOBIUM LEGUMINOSARUM BV TRIFOLII AND MYCORRHIZAL FUNGI IN AN ANDISOL AT DIFFERENT LEVELS OF ALUMINIUM SATURATION  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish La fitotoxicidad por Al es una seria limitante de la productividad de praderas crecidas sobre suelos volcánicos afectando la nodulación y efectividad de los Rhizobium. El objetivo del estudio consistió en seleccionar cepas de Rhizobium de colección para estudiar su efectividad en Trifolium repens cr [...] ecido en un Andisol con cepas nativas y distinta saturación de Al. Para ello se evaluó previamente en caldo nutritivo la tolerancia a la acidez y toxicidad por Al de 12 cepas de colección mediante control de curvas de crecimiento. Paralelamente, se inocularon los Rhizobium en un Andisol para evaluar su efectividad mediante rendimiento de Trifolium pratense. Se seleccionaron las cepas R-109, R-113 y R-115 para inocularlas en el Andisol utilizando cuatro tratamientos: suelo adicionado de 2 Mg CaCO3 ha-1 (SAl1), un testigo (SAl2) y suelo adicionado de dos niveles de saturación Al (SAl1, SAl4) utilizando Trifolium repens como hospedero. Las plantas mostraron capacidad para asociarse con las especies inoculadas presentando mayor efectividad R-113-SAl1 sinergismo positivo expresado en variables microbiológicas como nodulación (16 nódulos maceta-1), esporas de hongos micorrícicos arbusculares, HMA (384 esporas 100g-1), colonización HMA (45%) junto con variables agronómicas alcanzándose un incremento de biomasa foliar (93,5%) frente al testigo. Niveles más elevados de Al afectaron la inoculación con cepas de colección; así, con R-109 se obtuvo el menor crecimiento radical y nodulación respecto al suelo natural mientras que R-113 fue la cepa más efectiva. Abstract in english Aluminium phytotoxicity is a serious limitation of the productivity of prairies growing on volcanic soil by affecting nodulation and effectiveness of Rhizobium. The aim of this study was to select Rhizobium strains to determine the effect as inoculant on Trifolium repens cropped in an Andisol with d [...] ifferent aluminium saturation levels. Acidity tolerance (pH 4.5 and 6.0) of twelve Rhizobium strains of collection at three Al levels (100, 200, 300 µM) was evaluated in mineral nutritive medium vitro. Simultaneously, in a greenhouse trial, strains effectivity were tested by inoculation of Trifolium pratense growing in an acidic Andisol and compared with dry matter accumulation produced by native strains. According to the results of this two trials, three Rhizobium strains (R-109, R-113 and R-115) were selected to study the effect of their inoculation on Trifolium repens growth cropped in an Andisol at four Al saturation levels (SAl1 to SAl4). In addition, the effect on arbuscular mycorrhizal propagules was also studied. Plants showed different capacity for association with the inoculated strains giving the best response R-113 at SAl1 level with positive synergism expressed by microbiological parameters such as high nodulation (16 nodules pot-1), AMF spore number (384 spores 100 g-1), root colonization percentage (45%), together with agronomical variables with an increase of aerial phytomass (93,5%) in comparison with the control. Higher Al levels had an deleterious effect on the inoculation of collection strains; therefore, with R-109 strain inoculation the smallest root growth and nodulation were observed in comparison with soil with native strains whereas R-113 was the more effective one.

Claudia G, Castillo R; Rosa, Rubio H; Horacio, Urzúa S; Fernando, Borie B.

396

Common bean cultivars performance under Rhizobium inoculation and the relation between yield components traitsDesempenho de cultivares de feijoeiro sob inoculação com Rhizobium e relação entre os caracteres componentes do rendimento de grãos  

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Full Text Available The objectives of this study was to evaluate the Rhizobium inoculation effect on the grain yield characters in common bean cultivars, to quantify the possible relationship between these characters, and verify the genetic similarity among cultivars to suggest possible combinations to be adopted in crosses by breeding programs. It was evaluated six commercial common bean cultivars (IAPAR 81, Carioca, SCS-202 Guará, BRS Valente, FTS Soberano e IPR Uirapuru, with and without inoculation of Rhizobium bacteria. The experimental design was randomized block design with four replications, in factorial arrangement (6x2, with six cultivars and two inoculation levels. Each plot had six rows with three meters in length and 0.50 meters between rows, with 4 m2 plot. The yield components traits in common bean, under the conditions of this study, do not show to be influenced by Rhizobium’s inoculation. The number of grains per pod has a relation with the definition of yield per area in commercial common bean cultivars, while the numbers of pods and grains per plant showed strong positive correlation with grain yield per plant. The SCS-202 Guará, FTS Soberano e IPR Uirapuru cultivars show high grain yield, characterizing potential parents to be adopted in bean breeding programs.Os objetivos deste trabalho foram avaliar o efeito da inoculação com Rhizobium sobre os caracteres de rendimento de grãos em cultivares comerciais de feijoeiro, quantificar as possíveis relações entre estes caracteres, e verificar a similaridade genética entre as cultivares avaliadas a fim de sugerir possíveis genitores para compor combinações promissoras a serem adotadas em cruzamentos artificiais pelos programas de melhoramento. Foram avaliadas seis cultivares comerciais de feijoeiro (IAPAR 81, Carioca, SCS-202 Guará, BRS Valente, FTS Soberano e IPR Uirapuru, com e sem a inoculação de bactérias do gênero Rhizobium. O delineamento experimental utilizado foi blocos ao acaso, com quatro repetições, onde os tratamentos foram combinados em esquema fatorial (6 x 2, sendo seis cultivares e dois níveis de inoculação. Cada parcela foi constituída por seis linhas de três metros de comprimento espaçadas em 0,50 m, com área útil de 4m2. Os componentes do rendimento de grãos em feijoeiro, nas condições de realização deste estudo, não mostram ser influenciadas pela inoculação com Rhizobium. O caráter número de grãos por legume apresenta relação positiva com a definição da produtividade de grãos por área em cultivares comerciais de feijoeiro, enquanto que os números de legumes e de grãos por planta evidenciam forte correlação positivas com a produção de grãos por planta. A cultivar BRS Valente apresenta maior dissimilaridade genética no grupo de genótipos avaliados. As cultivares SCS-202 Guará, FTS Soberano e IPR Uirapuru evidenciam elevado rendimento de grãos, caracterizando genitores potenciais a serem adotados em programas de melhoramento do feijoeiro.

Julio Cesar Pires Santos

2011-08-01

397

INTERACCIÓN RHIZOBIUM LEGUMINOSARUM BV TRIFOLII Y HONGOS MICORRÍCICOS EN UN ANDISOL CON DIFERENTES NIVELES DE SATURACIÓN DE ALUMINIO INTERACTION OF RHIZOBIUM LEGUMINOSARUM BV TRIFOLII AND MYCORRHIZAL FUNGI IN AN ANDISOL AT DIFFERENT LEVELS OF ALUMINIUM SATURATION  

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Full Text Available La fitotoxicidad por Al es una seria limitante de la productividad de praderas crecidas sobre suelos volcánicos afectando la nodulación y efectividad de los Rhizobium. El objetivo del estudio consistió en seleccionar cepas de Rhizobium de colección para estudiar su efectividad en Trifolium repens crecido en un Andisol con cepas nativas y distinta saturación de Al. Para ello se evaluó previamente en caldo nutritivo la tolerancia a la acidez y toxicidad por Al de 12 cepas de colección mediante control de curvas de crecimiento. Paralelamente, se inocularon los Rhizobium en un Andisol para evaluar su efectividad mediante rendimiento de Trifolium pratense. Se seleccionaron las cepas R-109, R-113 y R-115 para inocularlas en el Andisol utilizando cuatro tratamientos: suelo adicionado de 2 Mg CaCO3 ha-1 (SAl1, un testigo (SAl2 y suelo adicionado de dos niveles de saturación Al (SAl1, SAl4 utilizando Trifolium repens como hospedero. Las plantas mostraron capacidad para asociarse con las especies inoculadas presentando mayor efectividad R-113-SAl1 sinergismo positivo expresado en variables microbiológicas como nodulación (16 nódulos maceta-1, esporas de hongos micorrícicos arbusculares, HMA (384 esporas 100g-1, colonización HMA (45% junto con variables agronómicas alcanzándose un incremento de biomasa foliar (93,5% frente al testigo. Niveles más elevados de Al afectaron la inoculación con cepas de colección; así, con R-109 se obtuvo el menor crecimiento radical y nodulación respecto al suelo natural mientras que R-113 fue la cepa más efectiva.Aluminium phytotoxicity is a serious limitation of the productivity of prairies growing on volcanic soil by affecting nodulation and effectiveness of Rhizobium. The aim of this study was to select Rhizobium strains to determine the effect as inoculant on Trifolium repens cropped in an Andisol with different aluminium saturation levels. Acidity tolerance (pH 4.5 and 6.0 of twelve Rhizobium strains of collection at three Al levels (100, 200, 300 µM was evaluated in mineral nutritive medium vitro. Simultaneously, in a greenhouse trial, strains effectivity were tested by inoculation of Trifolium pratense growing in an acidic Andisol and compared with dry matter accumulation produced by native strains. According to the results of this two trials, three Rhizobium strains (R-109, R-113 and R-115 were selected to study the effect of their inoculation on Trifolium repens growth cropped in an Andisol at four Al saturation levels (SAl1 to SAl4. In addition, the effect on arbuscular mycorrhizal propagules was also studied. Plants showed different capacity for association with the inoculated strains giving the best response R-113 at SAl1 level with positive synergism expressed by microbiological parameters such as high nodulation (16 nodules pot-1, AMF spore number (384 spores 100 g-1, root colonization percentage (45%, together with agronomical variables with an increase of aerial phytomass (93,5% in comparison with the control. Higher Al levels had an deleterious effect on the inoculation of collection strains; therefore, with R-109 strain inoculation the smallest root growth and nodulation were observed in comparison with soil with native strains whereas R-113 was the more effective one.

Claudia G Castillo R

2008-01-01

398

Terrains et perspectives  

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L'auteur analyse le malentendu existant entre recherche fondamentale et recherche appliquée et suggère que ce malentendu réside dans la nature politique de la recherche appliquée assimilée au développement.

1987-01-01

399

Selection of Rhizobium strain from Wonogiri, Central Java on the growth of soybean (Glycine max L. on the sand sterile medium in greenhouse  

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Full Text Available An experiment on the selection of Rhizobium strain from Wonogiri, Central Java on the growth of soybean (Glycine max L. on the sand sterile medium in green house. The aim of the experiment the selection and potency of the Rhizobium strain to increase the growth of soybean. The experiment was carried out in green house condition in Microbiology Division, Research Center for Biology-LIPI with sterile sand medium. The research design was Completely Randomized Design with three replications for each treatment. The Rhizobium strains used were 1 W (isolated from bean, Vigna radiata, 2 W (isolated from soybean, 3 W (isolated from bean, 4 W (isolated from soybean, 5 W (isolated from soybean, 6 W (isolated from peanut, Arachis hypogaea, 7 W (isolated from peanut, 8 W (isolated from peanut, the controls were uninoculated with Rhizobium strain and without urea fertilizer (K1, uninoculated and with urea fertilizer equal 100 kg/ha (K2. The plants were harvested after 50 days, the variable of investigation were the dry weight of canopy, roots, nodules root, total plants, number of nodules and ‘symbiotic capacity”. The results showed that all of experiment plant which be inoculated with Rhizobium able to form nodule. Strain of 2 W (isolated from soybean has given the best effects on the growth of soybean.

SRI PURWANINGSIH

2005-07-01

400

Vin et Mondialisation : préface  

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Full Text Available L’actualité cinématographique de ces derniers mois avec la sortie de Mondovino et Sideways illustre un certain nombre de tensions qui s’attachent à la mondialisation du produit “vin” et au soi-disant clivage entre le Nouveau Monde et la Vieille Europe, la marque et le terroir, la modernité et la tradition, autant de concepts masquant la complexité de ce processus. Le terme de ‘mondialisation’, d’usage fort répandu dans les médias, mérite sans doute quelques précautions. L’usage courant renvoi...

Chantal Crenn

2004-12-01

 
 
 
 
401

Cartographie et intelligence artificielle  

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Full Text Available Le monde complexe dans lequel nous évoluons est aussi paradoxal : ainsi, que peut-on prédire quant à la diffusion du savoir faire des géographes en termes de cartographie et de visualisation de l’information géographique ? On voit surgir toujours plus d’instruments et d’occasions de se repérer et d’admirer des images de la terre, mais il n’est pas sûr que cela fasse progresser dans le public la connaissance des cartes et de leur interprétation. Prenons l’exemple du repérage, par GPS, et bient...

Denise Pumain

2005-11-01

402

Perturabation of nodular operation under salt and water deficit stress in rhizobium common bean symbiosis  

International Nuclear Information System (INIS)

This work aims at the search for markers of tolerance to the osmotic stress and nodular efficiency of symbiosis Haricot Rhizobium. Thus, after having fixed the best period of hydroponic culture, we showed that a severe salt treatment generated an inhibition of the parameters of growth and nodulation. These inhibitions are accompanied by an inhibition of the enzymatic activities: ascorbate peroxidase (APX) and catalase (CAT), but an activation of peroxidase (POX) and superoxide dismutase (SOD), suggesting that these two antioxydants can be biochemical markers of the tolerance to salinity. To check the validity of these markers and to see the participation of the vegetable genotype in the response to the stress, we compared the effect of two concentrations salt 25 and 50 mM NaCe at two contrasting genotypes BAT477 tolerant and sensitive COCOT. This study illustrates the role of the vegetable genotype in the tolerance and efficiency and emphasize a significant result that SOD and POX constitute biochemical markers of tolerance to salinity. In order to ensure itself of the validity of this assumption in the event of water deficit stress, a treatment of 50 mM mannitol is applied to 16 symbioses formed by four genotypes of bean BAT477, COCOT, Flamingo and BRB17 inoculated by four strains of rhizobium CIAT899, 12 to 3, 1 to 6 and 8 to 3. This study permits us to make a screening of these symbioses according to their efficiency and their tolerance based on parameters of growth, of fixing and extent of the antioxydant enzymatic activities. It gets clear that the response of enzymatic antioxydants is in relation to the intrinsic potentialities of the partners of symbioses and appears to act as of the first stages of recognition plants bacterium. It will be retained that activities POX and SOD are markers of nodular tolerance. The CAT is the enzyme most connected to each partner of symbiosis and the APX would play a rather functional role. The heterogeneity of found answer indicates the great importance of the interaction of the two partners of symbiosis and of their contribution in great variability. The whole of results permits us to choose contrasting symbioses for better elucidating the mechanisms of nodular operation in response to the osmotic stress. (author). 282 refs

2006-01-01

403

Un nouvel habitat du Bronze final IIIb dans le Val d’Orléans et ses traces de métallurgie du fer : Bonnée, Les Terres à l’Est du Bourg (Centre, Loiret A new settlement from late Bronze IIIb in the val d’Orléans: Bonnée, Les Terres à l’Est du Bourg (lands to the east of the town (Centre, Loiret  

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Full Text Available La multiplication récente des diagnostics archéologiques autour du petit bourg actuel de Bonnée a permis la détection d’une occupation du Bronze final IIIb (circa 900-750 av. n.-e. sur environ un hectare aux Terres à l’Est du Bourg. Les limites inhérentes à ce type d’intervention réduisent l’interprétation des structures et toute approche spatiale de ce probable habitat repéré. L’étude conjointe des différents mobiliers en particulier céramique et métallurgique, mais aussi le torchis et la faune, atteste de sa culture matérielle et de son intérêt. Ces scories pourraient être parmi les plus anciennes traces en région Centre d’activité métallurgique du fer. Des activités de post-réduction sont avérées et certaines opérations de forgeage sont supposées.La découverte de cet habitat dans ce secteur du lit majeur de la Loire, apporte de nouvelles données concernant l’occupation du sol et ses problématiques évolutives dans le Val d’Orléans sur ces périodes de transition avec le Hallstatt ancien.The recent increase in the archaeological evaluations around the village of Bonnée has enabled the discovery of a final Bronze Age IIIb settlement (circa 900-750 BP on about a hectare of the Terres à l’Est du Bourg. The limits inherent in this type of work restrict the interpretation of structures and all spatial approaches to this likely dwelling. The joint study of the different furnishings, in particular ceramics and metal, but also the cob and fauna, attests to its material culture and its interest. The slag could be amongst the oldest iron metallurgy remains from the Centre region. Some activities of post-forging are proven and certain operations are guessed at. The discovery of this settlement in this sector of the major bed of the Loire, has produced new data concerning the occupation of the land and its evolutionary problems in the valley of Orleans over these periods of transition in the early Hallstatt.

Stéphane Joly

2011-12-01

404

Etude de faisabilité de la mise en place d’une base de données de morbidité en médecine générale en Wallonie et à Bruxelles. Rapport final du groupe Fédération Wallonie Bruxelles. REGM-Fr  

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La question posée par le Service Public Fédéral. Santé Publique, Direction des Soins Primaires est de savoir s’il est possible de possible de constituer avec les médecins généralistes un système d’enregistrement de données en provenance de l’exercice professionnel en soins primaires qui puissent aider l’administration de la santé publique dans ses processus informatifs et décisionnels. L’équipe de chercheurs s’est lancée dans l’étude de l’existant, tant en Belgiq...

2011-01-01

405

Is 'Final' Really Final?  

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Recently, the Appeal Committee of the Hong Kong Court of Final Appeal raised the question of whether that court had the power to hear an appeal against a decision of the Court of Appeal. The decision in question concerned a judgment of professional misconduct against an accountant by a disciplinary committee under the Professional Accountants Ordinance. The ordinance clearly states that the decision of the Court of Appeal is final. This article examines whether the Court of Final Appeal has t...

2002-01-01

406

La balle et la plume  

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Full Text Available Fin octobre 2008, la nouvelle fit l’effet d’une bombe : Barack Obama, alors candidat à la présidence américaine, demanda à la chaîne câblée Fox News de retarder le début du sixième match de la World Series de base-ball afin de diffuser un spot de campagne. Son adversaire, John McCain, soutenu par le camp républicain et une partie de la population, monta aussitôt au créneau pour dénoncer l’hérésie : s’arroger le droit de perturber cette grande finale du championnat au déroulement immuable reve...

Peter Marquis

2012-06-01

407

Role of nickel in membrane-bound hydrogenase and nickel metabolism in Rhizobium japonicum  

International Nuclear Information System (INIS)

The membrane-bound hydrogenase of Rhizobium japonicum requires nickel for activity. Radioactive "6"3Ni co-migrates with hydrogenase activity in native gel systems and co-elutes with purified hydrogenase form an affinity matrix column. A simplified scheme for the purification of hydrogenase has been developed and constitutes the first report of the aerobic purification of this enzyme from R. japonicum. The aerobic purification utilizes the general affinity matrix. Reactive Red 120-agarose and results in higher specific activity and yield of enzyme than previously reported. The stability of aerobically purified hydrogenase to oxygen is substantially greater than that reported for anaerobically isolated enzyme. Reduction of the aerobically purified enzyme in the presence of oxygen, however, results in the rapid loss of activity. R. japonicum cells accumulate nickel during heterotrophic growth and as non-growing cells. The hydrogenase constitutive mutant SR470 accumulates substantially greater amounts of nickel under both conditions. Kinetic studies indicate that the nickel uptake system in the hydrogenase constitutive mutant SR470 is upregulated relative to SRwt cells. The uptake system is specific for nickel, although a 10-fold excess (relative to nickel) of copper or zinc inhibits nickel uptake. The nickel uptake system appears to require energy. Under nickel-free conditions hydrogenase protein is not synthesized as determined by cross-reactivity with antibodies directed against hydrogenase, indicating that nickel regulates the formation of the enzyme as well as being a constituent of the active protein

1986-01-01

408

Rhizobium sp. effects, irradiated with ultraviolet and gamma rays, on nodulation of P. vulgaris (L.) bean  

International Nuclear Information System (INIS)

Indigenous isolates of Rhizobium sp. from the root nodules of bean were selected. There of these isolates and a R. leguminosarum biovar phaseoli (SEMIA 4064) strain, used as a reference, were irradiated with ultraviolet (UV) light and gamma-Rays (?-R). The relations between survival and fluence of UV, and survival and absorbed dose of ?-R were linear for the strain of reference. The D37 values, for this rhizobial strain were 43 j.m-2 for the UV-treatment, and 32 Gy for the ?-rays treatment. Through a greenhouse experiment the irradiated isolates were inoculated on bean seedlings (P. vulgaris L, Variety IPA-8), in an attempt to evaluate sensitivity of the host-plants and possible effects on their nodulation. Significant differences were observed only for root dry matter yield. For all the other evaluated parameters variance was of such magnitude that it was not possible to detect significance of the effects. The isolates tested showed difference in responses to nodulation, due to the effects of irradiations. The host plant (IPA-8) seemed to be sensitive to the possible modifications in the irradiated isolates. (author). 10 refs, 6 figs, 1 tab

1994-09-02

409

Increased effectiveness of competitive rhizobium strains upon inoculation of Cajanus cajan  

International Nuclear Information System (INIS)

A field study was conducted in lysimeters containing 15N-enriched soil to determine the effects of four competitive rhizobium strains upon yield parameters of pigeon peas (Cajanus cajan). The greatest differences observed were in seed yields; strain P132 effected the highest seed yield (121 +/- 20 g per plant), and the control strain (indigenous rhizobia) effected the lowest yield (43.9 +/- 8 g per plant). With the exception of seeds and pods, the dry matter weights were not different. Although there appeared to be no effect by inoculum strains on the fractional content of N derived from biological nitrogen fixation when the total plant biomass was considered, strains P132 and 401 partitioned more of the N derived from fixation into seeds and leaves than did the other strains. Because the seeds comprised the major portion of plant N, more total N and more N derived from biological nitrogen fixation (about half of total N) were found in plants inoculated with P132, whereas the smallest amount was found in the uninoculated controls. P132 was also the best competitor with respect to indigenous rhizobia and accounted for all of the nodules found on the plants in which it was inoculated

1987-01-01

410

Osmotic control of glycine betaine biosynthesis and degradation in Rhizobium meliloti  

International Nuclear Information System (INIS)

Intracellular accumulation of glycine betaine has been shown to confer an enhanced level of osmotic stress tolerance in Rhizobium meliloti. In this study, the authors used a physiological approach to investigate the mechanism by which glycine betaine is accumulated in osmotically stressed R. meliloti. Results from growth experiments, 14C labeling of intermediates, and enzyme activity assays are presented. The results provide evidence for the pathway of biosynthesis and degradation of glycine betaine and the osmotic effects on this pathway. High osmolarity in the medium decreased the activities of the enzymes involved in the degradation of glycine betaine but not those of enzymes that lead to its biosynthesis from choline. Thus, the concentration of the osmoprotectant glycine betaine is increased in stressed cells. This report demonstrates the ability of the osmolarity of the growth medium to regulate the use of glycine betaine as a carbon and nitrogen source or as an osmoprotectant. The mechanisms of osmoregulation in R. meliloti and Escherichia coli are compared

1988-01-01

411

Isolation of Rhizobium Spp. Bacteria which as Used Microbial Fertilizer from Wild Leguminosarum Plants  

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Full Text Available In our study used wild leguminous plants (Medicago sativa, M. lupulina and M. varia Erzurum belongs to the high altitude (2000 - 2500m regions ( Palandöken mountain, Alibaba mountain, Turnagöl mountain, Hasanbaba mountain, E?erli mountain, Y?ld?r?m mountain, Çubuklu mountain, Deveboynu locality, Kayakyolu locality, Telsizler and Dumlu hill were collected during the months of June and July. Nodules were obtained from this plant were sterilized, YMA (Yeast Mannitol Agar plates were streaked and petri dishes 28+1ºC were incubated for 3-5 days. Colonies appear after incubation typically constitute (white, clear or slightly opaque, mucosity, round, raised 39 isolates were selected and transferred to tubes and refrigerated YMA were stored at +4ºC. In the next stage, cytological and biochemical analyzes of these isolates were studied to determine. For this purpose isolates; YMA containing bromothymol blue and congo red reproduction, gram stain reaction, movement and subjected to catalase and oxidase tests were evaluated. The cytological and biochemical analysis of results showed that 28 of 39 strains belonged to Rhizobium spp.

Hatice Ö?ütcü

2014-04-01

412

Optimization of culture conditions for exopolysaccharides production in Rhizobium sp. using the response surface method  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english The combined effects of the processing parameters for exopolysaccharides production by Rhizobium sp. was studied using the experimental design and response surface methodology. The experiments were carried out using a fermenter with 20 L capacity, as the reactor. All processing parameters were onlin [...] e monitored. The temperature [(30 ± 1)ºC] and pH value (7.0 ± 0.1) were kept constant throughout the experimental time. As statistical tools, a complete 2³ factorial planning with central point and response surface were used to study the interactions among three relevant variables of the fermentation process: calcium carbonate concentration, aeration and agitation. The processing parameters setup for reaching a maximum response for exopolysaccharides production was obtained when applying the highest values for calcium carbonate concentration (1.1 g/L), aeration (1.3 vvm) and agitation (800 rpm). In addition, the combination of these optimum processing parameters yielded Y P/S (g/g) = 0.35.

Flávia, Pereira Duta; Francisca, Pessôa de França; Léa Maria, de Almeida Lopes.

2006-07-15

413

Preparation and biological evaluation of a novel selenium-containing exopolysaccharide from Rhizobium sp. N613.  

Science.gov (United States)

In order to obtain a low toxic antitumor agent and an organic selenium source, an exopolysaccharide obtained from Rhizobium sp. N613 (REPS) was modified by selenious acid using barium chloride as the catalyst. The reaction conditions were optimized by response surface methodology (RSM), and the optimal conditions for preparation of selenium-containing REPS (Se-REPS) were obtained. The selenium content of Se-REPS was 790 ?g/g under these conditions. The molecular structure of Se-REPS was confirmed by FTIR. In vitro antitumor activity of Se-REPS was evaluated by MTT assay, and the results indicated that Se-REPS could significantly inhibit the growth of S180 and HepG2 cells. Furthermore, Se-REPS exhibited comparable in vivo antitumor efficacy to cyclophosphamide at same concentrations. In addition, Se-REPS could substantially elevate the thymus and spleen indices in tumor-bearing mice. This study demonstrates that Se-REPS holds great potential to be a desirable antitumor agent for therapeutic and immunomodulatory applications. PMID:24815397

Ding, Guo-Bin; Nie, Rui-Hong; Lv, Li-Hua; Wei, Guo-Qin; Zhao, Liang-Qi

2014-08-30

414

New Betaproteobacterial Rhizobium Strains Able To Efficiently Nodulate Parapiptadenia rigida (Benth.) Brenan  

Science.gov (United States)

Among the leguminous trees native to Uruguay, Parapiptadenia rigida (Angico), a Mimosoideae legume, is one of the most promising species for agroforestry. Like many other legumes, it is able to establish symbiotic associations with rhizobia and belongs to the group known as nitrogen-fixing trees, which are major components of agroforestry systems. Information about rhizobial symbionts for this genus is scarce, and thus, the aim of this work was to identify and characterize rhizobia associated with P. rigida. A collection of Angico-nodulating isolates was obtained, and 47 isolates were selected for genetic studies. According to enterobacterial repetitive intergenic consensus PCR patterns and restriction fragment length polymorphism analysis of their nifH and 16S rRNA genes, the isolates could be grouped into seven genotypes, including the genera Burkholderia, Cupriavidus, and Rhizobium, among which the Burkholderia genotypes were the predominant group. Phylogenetic studies of nifH, nodA, and nodC sequences from the Burkholderia and the Cupriavidus isolates indicated a close relationship of these genes with those from betaproteobacterial rhizobia (beta-rhizobia) rather than from alphaproteobacterial rhizobia (alpha-rhizobia). In addition, nodulation assays with representative isolates showed that while the Cupriavidus isolates were able to effectively nodulate Mimosa pudica, the Burkholderia isolates produced white and ineffective nodules on this host.

Taule, Cecilia; Zabaleta, Maria; Mareque, Cintia; Platero, Raul; Sanjurjo, Lucia; Sicardi, Margarita; Frioni, Lillian; Battistoni, Federico

2012-01-01

415

Effect of Leguminous Lectins on the Growth of Rhizobium tropici CIAT899  

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Full Text Available Rhizobium tropici is a Gram-negative bacterium that induces nodules and fixed atmospheric nitrogen in symbiotic association with Phaseolus vulgaris (common bean and some other leguminous species. Lectins are proteins that specifically bind to carbohydrates and, consequently, modulate different biological functions. In this study, the d-glucose/ d-mannose-binding lectins (from seeds of Dioclea megacarpa, D. rostrata and D. violacea and D-galactose-binding lectins (from seeds of Bauhinia variegata, Erythina velutina and Vatairea macrocarpa were purified using chromatographic techniques and evaluated for their effect on the growth of R. tropici CIAT899. All lectins were assayed with a satisfactory degree of purity according to SDS-PAGE analysis, and stimulated bacterial growth; in particular, the Dioclea rostrata lectin was the most active among all tested proteins. As confirmed in the present study, both d-galactose- and d-glucose/d-mannose-binding lectins purified from the seeds of leguminous plants may be powerful biotechnological tools to stimulate the growth of R. tropici CIAT99, thus improving symbiotic interaction between rhizobia and common bean and, hence, the production of this field crop.

Mayron Alves de Vasconcelos

2013-05-01

416

Increased effectiveness of competitive rhizobium strains upon inoculation of Cajanus cajan  

Energy Technology Data Exchange (ETDEWEB)

A field study was conducted in lysimeters containing /sup 15/N-enriched soil to determine the effects of four competitive rhizobium strains upon yield parameters of pigeon peas (Cajanus cajan). The greatest differences observed were in seed yields; strain P132 effected the highest seed yield (121 +/- 20 g per plant), and the control strain (indigenous rhizobia) effected the lowest yield (43.9 +/- 8 g per plant). With the exception of seeds and pods, the dry matter weights were not different. Although there appeared to be no effect by inoculum strains on the fractional content of N derived from biological nitrogen fixation when the total plant biomass was considered, strains P132 and 401 partitioned more of the N derived from fixation into seeds and leaves than did the other strains. Because the seeds comprised the major portion of plant N, more total N and more N derived from biological nitrogen fixation (about half of total N) were found in plants inoculated with P132, whereas the smallest amount was found in the uninoculated controls. P132 was also the best competitor with respect to indigenous rhizobia and accounted for all of the nodules found on the plants in which it was inoculated.

Hernandez, B.S.; Poth, M.; Focht, D.D.

1987-09-01

417

Transformation of pWWO in Rhizobium leguminosarum DPT to Engineer Toluene Degrading Ability for Rhizoremediation.  

Science.gov (United States)

Rhizoremediation of organic xenobiotics is based on interactions between plants and their associated micro-organisms. The present work was designed to engineer a bacterial system having toluene degradation ability along with plant growth promoting characteristics for effective rhizoremediation. pWWO harboring the genes responsible for toluene breakdown was isolated from Pseudomonas putida MTCC 979 and successfully transformed in Rhizobium DPT. This resulted in a bacterial strain (DPT(T)) which had the ability to degrade toluene as well as enhance growth of host plant. The frequency of transformation was recorded 5.7 × 10(-6). DPT produced IAA, siderophore, chitinase, HCN, ACC deaminase, solubilized inorganic phosphate, fixed atmospheric nitrogen and inhibited the growth of Fusarium oxysporum and Macrophomina phaseolina in vitro. During pot assay, 50 ppm toluene in soil was found to inhibit the germination of Cajanus cajan seeds. However when the seeds bacterized with toluene degrading P. putida or R. leguminosarum DPT were sown in pots, again no germination was observed. Non-bacterized as well as bacterized seeds germinated successfully in toluene free soil as control. The results forced for an alternative mode of application of bacteria for rhizoremediation purpose. Hence bacterial suspension was mixed with soil having 50 ppm of toluene. Germination index in DPT treated soil was 100% while in P. putida it was 50%. Untreated soil with toluene restricted the seeds to germinate. PMID:23729882

Goel, Garima; Pandey, Piyush; Sood, Anchal; Bisht, Sandeep; Maheshwari, D K; Sharma, G D

2012-06-01

418

Escherichia coli BdcA controls biofilm dispersal in Pseudomonas aeruginosa and Rhizobium meliloti  

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Full Text Available Abstract Background Previously we showed that BdcA controls Escherichia coli biofilm dispersal by binding the ubiquitous bacterial signal cyclic diguanylate (c-di-GMP; upon reducing the concentration of c-di-GMP, the cell shifts to the planktonic state by increasing motility, decreasing aggregation, and decreasing production of biofilm adhesins. Findings Here we report that BdcA also increases biofilm dispersal in other Gram-negative bacteria including Pseudomonas aeruginosa, Pseudomonas fluorescens, and Rhizobium meliloti. BdcA binds c-di-GMP in these strains and thereby reduces the effective c-di-GMP concentrations as demonstrated by increases in swimming motility and swarming motility as well as by a reduction in extracellular polysaccharide production. We also develop a method to displace existing biofilms by adding BdcA via conjugation from E. coli in mixed-species biofilms. Conclusion Since BdcA shows the ability to control biofilm dispersal in diverse bacteria, BdcA has the potential to be used as a tool to disperse biofilms for engineering and medical applications.

Wood Thomas K

2011-10-01

419