Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| bradyrhizobia nodulating the acacia mangium x a. auriculiformis interspecific hybrid are specific and differ from those associated with both parental species. | in the context of an increasing utilization of the interspecific hybrid acacia mangium x a. auriculiformis as a plantation tree in the tropical humid zone, its symbiotic characterization was carried out in comparison with that of its two parental species. rhizobium strains of diverse geographical origins were isolated from root nodules of the hybrid and its parents. almost all acacia hybrid isolates were fast growing on yeast extract-mannitol medium, in contrast to those isolated from both paren ... | 2009 | 19854923 |
| topology of 4-pyridoxic acid dehydrogenase in transformed escherichia coli cells. | the topology of 4-pyridoxic acid dehydrogenase in the escherichia coli cell membrane was examined with transformed e. coli cells overexpressing the enzyme from mesorhizobium loti. the recombinant enzymes with a his(6)-tag either in the n-terminal region or at the c-terminus were localized on the e. coli cell membrane like the wild-type enzyme without a his(6)-tag. the his(6)-tags were labelled with ni-nta ap conjugate only when the e. coli protoplast cells were broken. the membrane-bound enzyme ... | 2010 | 19861399 |
| a type vi secretion system effector protein, vgrg1, from aeromonas hydrophila that induces host cell toxicity by adp ribosylation of actin. | we recently delineated the importance of a type vi secretion system (t6ss) gene cluster in the virulence of diarrheal isolate ssu of aeromonas hydrophila and showed that vash, a sigma(54) activator and t6ss component, was involved in the production of its associated effectors, e.g., hemolysin-coregulated protein. to identify additional t6ss effectors and/or secreted proteins, we subjected culture supernatants from deletion mutants of a. hydrophila, namely, a delta act mutant (a t2ss-associated c ... | 2010 | 19880608 |
| a type vi secretion system effector protein, vgrg1, from aeromonas hydrophila that induces host cell toxicity by adp ribosylation of actin. | we recently delineated the importance of a type vi secretion system (t6ss) gene cluster in the virulence of diarrheal isolate ssu of aeromonas hydrophila and showed that vash, a sigma(54) activator and t6ss component, was involved in the production of its associated effectors, e.g., hemolysin-coregulated protein. to identify additional t6ss effectors and/or secreted proteins, we subjected culture supernatants from deletion mutants of a. hydrophila, namely, a delta act mutant (a t2ss-associated c ... | 2010 | 19880608 |
| effectors, effectors et encore des effectors: the xiv international congress on molecular-plant microbe interactions, quebec. | 2009 | 19888813 | |
| nodulation gene mutants of mesorhizobium loti r7a-nodz and noll mutants have host-specific phenotypes on lotus spp. | rhizobial nod factors induce plant responses and facilitate bacterial infection, leading to the development of nitrogen-fixing root nodules on host legumes. nodule initiation is highly dependent on nod-factor structure and, hence, on at least some of the nodulation genes that encode nod-factor production. here, we report the effects of mutations in mesorhizobium loti r7a nodulation genes on nodulation of four lotus spp. and on nod-factor structure. most mutants, including a deltanodsdeltanolo do ... | 2009 | 19888820 |
| analysis of lipid export in hydrocarbonoclastic bacteria of the genus alcanivorax: identification of lipid export-negative mutants of alcanivorax borkumensis sk2 and alcanivorax jadensis t9. | triacylglycerols (tags), wax esters (wes), and polyhydroxyalkanoates (phas) are the major hydrophobic compounds synthesized in bacteria and deposited as cytoplasmic inclusion bodies when cells are cultivated under imbalanced growth conditions. the intracellular occurrence of these compounds causes high costs for downstream processing. alcanivorax species are able to produce extracellular lipids when the cells are cultivated on hexadecane or pyruvate as the sole carbon source. in this study, we d ... | 2010 | 19933359 |
| analysis of lipid export in hydrocarbonoclastic bacteria of the genus alcanivorax: identification of lipid export-negative mutants of alcanivorax borkumensis sk2 and alcanivorax jadensis t9. | triacylglycerols (tags), wax esters (wes), and polyhydroxyalkanoates (phas) are the major hydrophobic compounds synthesized in bacteria and deposited as cytoplasmic inclusion bodies when cells are cultivated under imbalanced growth conditions. the intracellular occurrence of these compounds causes high costs for downstream processing. alcanivorax species are able to produce extracellular lipids when the cells are cultivated on hexadecane or pyruvate as the sole carbon source. in this study, we d ... | 2010 | 19933359 |
| host plant genome overcomes the lack of a bacterial gene for symbiotic nitrogen fixation. | homocitrate is a component of the iron-molybdenum cofactor in nitrogenase, where nitrogen fixation occurs. nifv, which encodes homocitrate synthase (hcs), has been identified from various diazotrophs but is not present in most rhizobial species that perform efficient nitrogen fixation only in symbiotic association with legumes. here we show that the fen1 gene of a model legume, lotus japonicus, overcomes the lack of nifv in rhizobia for symbiotic nitrogen fixation. a fix(-) (non-fixing) plant mu ... | 2009 | 19940927 |
| novel tn4371-ice like element in ralstonia pickettii and genome mining for comparative elements. | integrative conjugative elements (ices) are important factors in the plasticity of microbial genomes. an element related to the ice tn4371 was discovered during a bioinformatic search of the ralstonia pickettii 12j genome. this element was analysed and further searches carried out for additional elements.a pcr method was designed to detect and characterise new elements of this type based on this scaffold and a culture collection of fifty-eight ralstonia pickettii and ralstonia insidiosa strains ... | 2009 | 19941653 |
| autonomous plasmid-like replication of a conjugative transposon. | integrative and conjugative elements (ices), a.k.a. conjugative transposons, are mobile genetic elements involved in many biological processes, including pathogenesis, symbiosis and the spread of antibiotic resistance. unlike conjugative plasmids that are extra-chromosomal and replicate autonomously, ices are integrated in the chromosome and replicate passively during chromosomal replication. it is generally thought that ices do not replicate autonomously. we found that when induced, bacillus su ... | 2010 | 19943900 |
| autonomous plasmid-like replication of a conjugative transposon. | integrative and conjugative elements (ices), a.k.a. conjugative transposons, are mobile genetic elements involved in many biological processes, including pathogenesis, symbiosis and the spread of antibiotic resistance. unlike conjugative plasmids that are extra-chromosomal and replicate autonomously, ices are integrated in the chromosome and replicate passively during chromosomal replication. it is generally thought that ices do not replicate autonomously. we found that when induced, bacillus su ... | 2010 | 19943900 |
| identification of the mesorhizobium loti gene responsible for glycerophosphorylation of periplasmic cyclic beta-1,2-glucans. | periplasmic cyclic beta-1,2-glucans play a crucial role in symbiosis as well as in hypo-osmotic adaptation for rhizobia. these glucans are modified in many species by anionic substituents such as glycerophosphoryl and succinyl ones, but their role remains to be examined. in this work, the cgma homolog is shown to be responsible for glycerophosphorylation of cyclic beta-1,2-glucans in mesorhizobium loti. the mutation in cgma converted most anionic glucans into neutral ones, leaving a small amount ... | 2010 | 19951365 |
| improved characterization of nod factors and genetically based variation in lysm receptor domains identify amino acids expendable for nod factor recognition in lotus spp. | formation of functional nodules is a complex process depending on host-microsymbiont compatibility in all developmental stages. this report uses the contrasting symbiotic phenotypes of lotus japonicus and l. pedunculatus, inoculated with mesorhizobium loti or the bradyrhizobium sp. (lotus), to investigate the role of nod factor structure and nod factor receptors (nfr) for rhizobial recognition, infection thread progression, and bacterial persistence within nodule cells. a key contribution was th ... | 2010 | 19958139 |
| a variety of regulatory mechanisms are involved in the nitrogen-dependent modulation of the nodule organogenesis program in legume roots. | combined nitrogen (n) sources are known to strongly affect initiation, development and functioning of nitrogen-fixing-nodules whose formation is triggered by lipochitin-oligosaccharide signals secreted in the rhizospere by the rhizobium partner. the rapid effects of n supply on nodule initiation have been mainly described when n sources are present at the moment of rhizobium inoculation or purified nod factors addition. we recently reported that high ammonium nitrate growth conditions might also ... | 2009 | 20009551 |
| salicylic acid differentially affects suspension cell cultures of lotus japonicus and one of its non-symbiotic mutants. | salicylic acid (sa) is known to play an important role in the interaction between plant and micro-organisms, both symbiotic and pathogen. in particular, high levels of sa block nodule formation and mycorrhizal colonization in plants. a mutant of lotus japonicus, named ljsym4-2, was characterized as unable to establish positive interactions with rhizobium and fungi (nod(-), myc(-)); in particular, it does not recognize signal molecules released by symbiotic micro-organisms so that eventually, epi ... | 2010 | 20012170 |
| sinorhizobium meliloti phospholipase c required for lipid remodeling during phosphorus limitation. | rhizobia are gram-negative soil bacteria able to establish nitrogen-fixing root nodules with their respective legume host plants. besides phosphatidylglycerol, cardiolipin, and phosphatidylethanolamine, rhizobial membranes contain phosphatidylcholine (pc) as a major membrane lipid. under phosphate-limiting conditions of growth, some bacteria replace their membrane phospholipids with lipids lacking phosphorus. in sinorhizobium meliloti, these phosphorus-free lipids are sulfoquinovosyl diacylglyce ... | 2010 | 20018679 |
| sinorhizobium meliloti phospholipase c required for lipid remodeling during phosphorus limitation. | rhizobia are gram-negative soil bacteria able to establish nitrogen-fixing root nodules with their respective legume host plants. besides phosphatidylglycerol, cardiolipin, and phosphatidylethanolamine, rhizobial membranes contain phosphatidylcholine (pc) as a major membrane lipid. under phosphate-limiting conditions of growth, some bacteria replace their membrane phospholipids with lipids lacking phosphorus. in sinorhizobium meliloti, these phosphorus-free lipids are sulfoquinovosyl diacylglyce ... | 2010 | 20018679 |
| nmr assignments of the dna binding domain of ml4 protein from mesorhizobium loti. | ml4 protein from mesorhizobium loti has a 58% sequence identity with the ros protein from agrobacterium tumefaciens that contains a prokaryotic cys(2)his(2) zinc finger domain. interestingly, ml4 is a zinc-lacking protein that does not contain the cys(2)his(2) motif and is able to bind the ros dna target sequence with high affinity. here we report the (1)h, (15)n and (13)c nmr assignments of the ml4 protein dna binding domain (residue 52-151), as an important step toward elucidating at a molecul ... | 2010 | 20020226 |
| rhizobium leguminosarum hupe encodes a nickel transporter required for hydrogenase activity. | 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 ... | 2010 | 20023036 |
| rhizobium leguminosarum hupe encodes a nickel transporter required for hydrogenase activity. | 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 ... | 2010 | 20023036 |
| functional role of bradyrhizobium japonicum trehalose biosynthesis and metabolism genes during physiological stress and nodulation. | trehalose, a disaccharide accumulated by many microorganisms, acts as a protectant during periods of physiological stress, such as salinity and desiccation. previous studies reported that the trehalose biosynthetic genes (otsa, tres, and trey) in bradyrhizobium japonicum were induced by salinity and desiccation stresses. functional mutational analyses indicated that disruption of otsa decreased trehalose accumulation in cells and that an otsa trey double mutant accumulated an extremely low level ... | 2010 | 20023090 |
| functional role of bradyrhizobium japonicum trehalose biosynthesis and metabolism genes during physiological stress and nodulation. | trehalose, a disaccharide accumulated by many microorganisms, acts as a protectant during periods of physiological stress, such as salinity and desiccation. previous studies reported that the trehalose biosynthetic genes (otsa, tres, and trey) in bradyrhizobium japonicum were induced by salinity and desiccation stresses. functional mutational analyses indicated that disruption of otsa decreased trehalose accumulation in cells and that an otsa trey double mutant accumulated an extremely low level ... | 2010 | 20023090 |
| amidoligases with atp-grasp, glutamine synthetase-like and acetyltransferase-like domains: synthesis of novel metabolites and peptide modifications of proteins. | recent studies have shown that the ubiquitin system had its origins in ancient cofactor/amino acid biosynthesis pathways. preliminary studies also indicated that conjugation systems for other peptide tags on proteins, such as pupylation, have evolutionary links to cofactor/amino acid biosynthesis pathways. following up on these observations, we systematically investigated the non-ribosomal amidoligases of the atp-grasp, glutamine synthetase-like and acetyltransferase folds by classifying the kno ... | 2009 | 20023723 |
| covariation of branch lengths in phylogenies of functionally related genes. | recent studies have shown evidence for the coevolution of functionally-related genes. this coevolution is a result of constraints to maintain functional relationships between interacting proteins. the studies have focused on the correlation in gene tree branch lengths of proteins that are directly interacting with each other. we here hypothesize that the correlation in branch lengths is not limited only to proteins that directly interact, but also to proteins that operate within the same pathway ... | 2009 | 20041191 |
| conserved symbiotic plasmid dna sequences in the multireplicon pangenomic structure of rhizobium etli. | strains of the same bacterial species often show considerable genomic variation. to examine the extent of such variation in rhizobium etli, the complete genome sequence of r. etli ciat652 and the partial genomic sequences of six additional r. etli strains having different geographical origins were determined. the sequences were compared with each other and with the previously reported genome sequence of r. etli cfn42. dna sequences common to all strains constituted the greater part of these geno ... | 2010 | 20048063 |
| structural determinants of substrate recognition in the had superfamily member d-glycero-d-manno-heptose-1,7-bisphosphate phosphatase (gmhb) . | the haloalkanoic acid dehalogenase (had) enzyme superfamily is the largest family of phosphohydrolases. in had members, the structural elements that provide the binding interactions that support substrate specificity are separated from those that orchestrate catalysis. for most had phosphatases, a cap domain functions in substrate recognition. however, for the had phosphatases that lack a cap domain, an alternate strategy for substrate selection must be operative. one such had phosphatase, gmhb ... | 2010 | 20050614 |
| divergence of biochemical function in the had superfamily: d-glycero-d-manno-heptose-1,7-bisphosphate phosphatase (gmhb). | d-glycero-d-manno-heptose-1,7-bisphosphate phosphatase (gmhb) is a member of the histidinol-phosphate phosphatase (hisb) subfamily of the haloalkanoic acid dehalogenase (had) enzyme superfamily. gmhb supports two divergent biochemical pathways in bacteria: the d-glycero-d-manno-heptose-1alpha-gdp pathway (in s-layer glycoprotein biosynthesis) and the l-glycero-d-manno-heptose-1beta-adp pathway (in lipid a biosynthesis). herein, we report the comparative analysis of substrate recognition in selec ... | 2010 | 20050615 |
| global transcriptional analysis of nitrogen fixation and ammonium repression in root-associated pseudomonas stutzeri a1501. | biological nitrogen fixation is highly controlled at the transcriptional level by regulatory networks that respond to the availability of fixed nitrogen. in many diazotrophs, addition of excess ammonium in the growth medium results in immediate repression of nif gene transcription. although the regulatory cascades that control the transcription of the nif genes in proteobacteria have been well investigated, there are limited data on the kinetics of ammonium-dependent repression of nitrogen fixat ... | 2010 | 20053297 |
| fimr and fims: biofilm formation and gene expression in porphyromonas gingivalis. | porphyromonas gingivalis is a late-colonizing bacterium of the subgingival dental plaque biofilm associated with periodontitis. two p. gingivalis genes, fimr and fims, are predicted to encode a two-component signal transduction system comprising a response regulator (fimr) and a sensor histidine kinase (fims). in this study, we show that fims and fimr, although contiguous on the genome, are not part of an operon. we inactivated fimr and fims in both the afimbriated strain w50 and the fimbriated ... | 2010 | 20061484 |
| analysis of two potential long-distance signaling molecules, ljcle-rs1/2 and jasmonic acid, in a hypernodulating mutant too much love. | legume plants tightly control the number and development of root nodules. this is partly regulated by a long-distance signaling known as auto-regulation of nodulation (aon). aon signaling involves at least two potential long-distance signals: root-derived signal and shoot-derived signal. however, their molecular characteristics and the mode of action remain unclear. in our recent study, we isolated a novel lotus japonicus hypernodulating mutant too much love (tml). based on several grafting expe ... | 2010 | 20061808 |
| identification and functional analysis of type iii effector proteins in mesorhizobium loti. | mesorhizobium loti maff303099, a microsymbiont of the model legume lotus japonicus, possesses a cluster of genes (tts) that encode a type iii secretion system (t3ss). in the presence of heterologous nodd from rhizobium leguminosarum and a flavonoid naringenin, we observed elevated expression of the tts genes and secretion of several proteins into the culture medium. inoculation experiments with wild-type and t3ss mutant strains revealed that the presence of the t3ss affected nodulation at a spec ... | 2010 | 20064065 |
| the sinorhizobium meliloti rna chaperone hfq mediates symbiosis of s. meliloti and alfalfa. | there exist commonalities between symbiotic sinorhizobium meliloti and pathogenic brucella bacteria in terms of extensive gene synteny and the requirements for intracellular survival in their respective hosts. the rna chaperone hfq is essential for virulence for several bacterial groups, including brucella; however, its role in s. meliloti has not been investigated. our studies of an s. meliloti loss-of-function hfq mutant have revealed that hfq plays a key role in the establishment of the symbi ... | 2010 | 20081033 |
| 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. | 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 gamma-proteobacteria but lately in several alpha-proteobacteria as well. here, we have compared an extensive compilation of these non-coding rna predictions to intergenic expression data of a whole-ge ... | 2010 | 20089193 |
| glycolysis and the tricarboxylic acid cycle are linked by alanine aminotransferase during hypoxia induced by waterlogging of lotus japonicus. | the role of nitrogen metabolism in the survival of prolonged periods of waterlogging was investigated in highly flood-tolerant, nodulated lotus japonicus plants. alanine production revealed to be a critical hypoxic pathway. alanine is the only amino acid whose biosynthesis is not inhibited by nitrogen deficiency resulting from rna interference silencing of nodular leghemoglobin. the metabolic changes that were induced following waterlogging can be best explained by the activation of alanine meta ... | 2010 | 20089769 |
| the systemic imprint of growth and its uses in ecological (meta)genomics. | microbial minimal generation times range from a few minutes to several weeks. they are evolutionarily determined by variables such as environment stability, nutrient availability, and community diversity. selection for fast growth adaptively imprints genomes, resulting in gene amplification, adapted chromosomal organization, and biased codon usage. we found that these growth-related traits in 214 species of bacteria and archaea are highly correlated, suggesting they all result from growth optimi ... | 2010 | 20090831 |
| structure determination and characterization of the vitamin b6 degradative enzyme (e)-2-(acetamidomethylene)succinate hydrolase. | the gene identification and kinetic characterization of (e)-2-(acetamidomethylene)succinate (e-2ams) hydrolase has recently been described. this enzyme catalyzes the final reaction in the degradation of vitamin b(6) and produces succinic semialdehyde, acetate, ammonia, and carbon dioxide from e-2ams. the structure of e-2ams hydrolase was determined to 2.3 a using sad phasing. e-2ams hydrolase is a member of the alpha/beta hydrolase superfamily and utilizes a serine/histidine/aspartic acid cataly ... | 2010 | 20099871 |
| effect of abscisic acid on symbiotic nitrogen fixation activity in the root nodules of lotus japonicus. | the phytohormone abscisic acid (aba) is known to be a negative regulator of legume root nodule formation. by screening lotus japonicus seedlings for survival on an agar medium containing 70 μm aba, we obtained mutants that not only showed increased root nodule number, but also enhanced nitrogen fixation. the mutant was designated enf1 (enhanced nitrogen fixation 1) and was confirmed to be monogenic and incompletely dominant. in long-term growth experiments with m. loti, although some yield param ... | 2010 | 20118670 |
| computational prediction of type iii secreted proteins from gram-negative bacteria. | type iii secretion system (t3ss) is a specialized protein delivery system in gram-negative bacteria that injects proteins (called effectors) directly into the eukaryotic host cytosol and facilitates bacterial infection. for many plant and animal pathogens, t3ss is indispensable for disease development. recently, t3ss has also been found in rhizobia and plays a crucial role in the nodulation process. although a great deal of efforts have been done to understand type iii secretion, the precise mec ... | 2010 | 20122221 |
| genomic and evolutionary comparisons of diazotrophic and pathogenic bacteria of the order rhizobiales. | species belonging to the rhizobiales are intriguing and extensively researched for including both bacteria with the ability to fix nitrogen when in symbiosis with leguminous plants and pathogenic bacteria to animals and plants. similarities between the strategies adopted by pathogenic and symbiotic rhizobiales have been described, as well as high variability related to events of horizontal gene transfer. although it is well known that chromosomal rearrangements, mutations and horizontal gene tra ... | 2010 | 20144182 |
| altered lipid a structures and polymyxin hypersensitivity of rhizobium etli mutants lacking the lpxe and lpxf phosphatases. | the lipid a of rhizobium etli, a nitrogen-fixing plant endosymbiont, displays significant structural differences when compared to that of escherichia coli. an especially striking feature of r. etli lipid a is that it lacks both the 1- and 4'-phosphate groups. the 4'-phosphate moiety of the distal glucosamine unit is replaced with a galacturonic acid residue. the dephosphorylated proximal unit is present as a mixture of the glucosamine hemiacetal and an oxidized 2-aminogluconate derivative. disti ... | 2010 | 20153447 |
| a new small regulatory protein, hmup, modulates haemin acquisition in sinorhizobium meliloti. | sinorhizobium meliloti has multiple systems for iron acquisition, including the use of haem as an iron source. haem internalization involves the shmr haem outer membrane receptor and the hmutuv locus, which participates in haem transport across the cytoplasmic membrane. previous studies have demonstrated that expression of the shmr gene is negatively regulated by iron through rira. here, we identify hmup in a genetic screen for mutants that displayed aberrant control of shmr. the normal inductio ... | 2010 | 20167620 |
| thiosulfate-dependent chemolithoautotrophic growth of bradyrhizobium japonicum. | thiosulfate-oxidizing sox gene homologues were found at four loci (i, ii, iii, and iv) on the genome of bradyrhizobium japonicum usda110, a symbiotic nitrogen-fixing bacterium in soil. in fact, b. japonicum usda110 can oxidize thiosulfate and grow under a chemolithotrophic condition. the deletion mutation of the soxy(1) gene at the sox locus i, homologous to the sulfur-oxidizing (sox) system in alphaproteobacteria, left b. japonicum unable to oxidize thiosulfate and grow under chemolithotrophic ... | 2010 | 20173070 |
| phylogenomics reveals a diverse rickettsiales type iv secretion system. | with an obligate intracellular lifestyle, alphaproteobacteria of the order rickettsiales have inextricably coevolved with their various eukaryotic hosts, resulting in small, reductive genomes and strict dependency on host resources. unsurprisingly, large portions of rickettsiales genomes encode proteins involved in transport and secretion. one particular transporter that has garnered recent attention from researchers is the type iv secretion system (t4ss). homologous to the well-studied archetyp ... | 2010 | 20176788 |
| synthesis of 4-diphosphocytidyl-2-c-methyl-d-erythritol 2-phosphate and kinetic studies of mycobacterium tuberculosis ispf. | many pathogenic bacteria utilize the 2-c-methyl-d-erythritol 4-phosphate (mep) pathway for the biosynthesis of isopentenyl diphosphate and dimethylallyl diphosphate, two major building blocks of isoprenoid compounds. the fifth enzyme in the mep pathway, 2-c-methyl-d-erythritol 2,4-cyclodiphosphate (me-cpp) synthase (ispf), catalyzes the conversion of 4-diphosphocytidyl-2-c-methyl-d-erythritol 2-phosphate (cdp-me2p) to me-cpp with a corresponding release of cytidine 5-monophosphate (cmp). because ... | 2010 | 20189102 |
| evolution and regulation of the lotus japonicus lysm receptor gene family. | lysm receptor kinases were identified as receptors of acylated chitin (nod factors) or chitin produced by plant-interacting microbes. here, we present the identification and characterization of the lysm receptor kinase gene (lys) family (17 members) in lotus japonicus. comprehensive phylogenetic analysis revealed a correlation between lys gene structure and phylogeny. further mapping coupled with sequence-based anchoring on the genome showed that the family has probably expanded by a combination ... | 2010 | 20192837 |
| the sinorhizobium meliloti rna chaperone hfq influences central carbon metabolism and the symbiotic interaction with alfalfa. | the bacterial hfq protein is able to interact with diverse rna molecules, including regulatory small non-coding rnas (srnas), and thus it is recognized as a global post-transcriptional regulator of gene expression. loss of hfq has an extensive impact in bacterial physiology which in several animal pathogens influences virulence. sinorhizobium meliloti is a model soil bacterium known for its ability to establish a beneficial nitrogen-fixing intracellular symbiosis with alfalfa. despite the predic ... | 2010 | 20205931 |
| heme-responsive dna binding by the global iron regulator irr from rhizobium leguminosarum. | heme, a physiologically crucial form of iron, is a cofactor for a very wide range of proteins and enzymes. these include dna regulatory proteins in which heme is a sensor to which an analyte molecule binds, effecting a change in the dna binding affinity of the regulator. given that heme, and more generally iron, must be carefully regulated, it is surprising that there are no examples yet in bacteria in which heme itself is sensed directly by a reversibly binding dna regulatory protein. here we s ... | 2010 | 20233710 |
| a metaproteomic analysis of the human salivary microbiota by three-dimensional peptide fractionation and tandem mass spectrometry. | metagenomics uses gene expression patterns to understand the taxonomy and metabolic activities of microbial communities. metaproteomics applies the same approach to community proteomes. previously, we used a novel three-dimensional peptide separation method to identify over 2000 salivary proteins. this study used those data to carry out the first metaproteomic analysis of the human salivary microbiota. the metagenomic software megan generated a phylogenetic tree, which was checked against the hu ... | 2010 | 20331792 |
| distinguishing microbial genome fragments based on their composition: evolutionary and comparative genomic perspectives. | it is well known that patterns of nucleotide composition vary within and among genomes, although the reasons why these variations exist are not completely understood. between-genome compositional variation has been exploited to assign environmental shotgun sequences to their most likely originating genomes, whereas within-genome variation has been used to identify recently acquired genetic material such as pathogenicity islands. recent sequence assignment techniques have achieved high levels of ... | 2010 | 20333228 |
| loss of the response regulator ctra causes pleiotropic effects on gene expression but does not affect growth phase regulation in rhodobacter capsulatus. | the purple nonsulfur photosynthetic bacterium rhodobacter capsulatus has been extensively studied for its metabolic versatility as well as for production of a gene transfer agent called rcgta. production of rcgta is highest in the stationary phase of growth and requires the response regulator protein ctra. the ctra protein in caulobacter crescentus has been thoroughly studied for its role as an essential, master regulator of the cell cycle. although the ctra protein in r. capsulatus shares a hig ... | 2010 | 20363938 |
| efficient recombinant expression and secretion of a thermostable gh26 mannan endo-1,4-beta-mannosidase from bacillus licheniformis in escherichia coli. | mannans are one of the key polymers in hemicellulose, a major component of lignocellulose. the mannan endo-1,4-beta-mannosidase or 1,4-beta-d-mannanase (ec 3.2.1.78), commonly named beta-mannanase, is an enzyme that can catalyze random hydrolysis of beta-1,4-mannosidic linkages in the main chain of mannans, glucomannans and galactomannans. the enzyme has found a number of applications in different industries, including food, feed, pharmaceutical, pulp/paper industries, as well as gas well stimul ... | 2010 | 20380743 |
| monomethylamine as a nitrogen source for a nonmethylotrophic bacterium, agrobacterium tumefaciens. | monomethylamine can be used by nonmethylotrophs as a sole nitrogen source but not as a carbon source; however, little is known about the genes and enzymes involved. the gamma-glutamylmethylamide/n-methylglutamate pathway for monomethylamine utilization by methylotrophs has recently been resolved. we have identified genes encoding key enzymes of this pathway in nonmethylotrophs (e.g., agrobacterium tumefaciens) and demonstrated that this pathway is also involved in the utilization of monomethylam ... | 2010 | 20400554 |
| expression and function of four carbonic anhydrase homologs in the deep-sea chemolithoautotroph thiomicrospira crunogena. | the hydrothermal vent chemolithoautotroph thiomicrospira crunogena grows rapidly in the presence of low concentrations of dissolved inorganic carbon (dic) (= co(2) + hco(3)(-) + co(3)(-2)). its genome encodes alpha-carbonic anhydrase (alpha-ca), beta-ca, carboxysomal beta-like ca (csosca), and a protein distantly related to gamma-ca. the purposes of this work were to characterize the gene products, determine whether they were differentially expressed, and identify those that are necessary for di ... | 2010 | 20400567 |
| a dominant function of ccamk in intracellular accommodation of bacterial and fungal endosymbionts. | in legumes, ca(2+)/calmodulin-dependent protein kinase (ccamk) is a component of the common symbiosis genes that are required for both root nodule (rn) and arbuscular mycorrhiza (am) symbioses and is thought to be a decoder of ca(2+) spiking, one of the earliest cellular responses to microbial signals. a gain-of-function mutation of ccamk has been shown to induce spontaneous nodulation without rhizobia, but the significance of ccamk activation in bacterial and/or fungal infection processes is no ... | 2010 | 20409002 |
| regulation of glycogen metabolism in yeast and bacteria. | microorganisms have the capacity to utilize a variety of nutrients and adapt to continuously changing environmental conditions. many microorganisms, including yeast and bacteria, accumulate carbon and energy reserves to cope with the starvation conditions temporarily present in the environment. glycogen biosynthesis is a main strategy for such metabolic storage, and a variety of sensing and signaling mechanisms have evolved in evolutionarily distant species to ensure the production of this homop ... | 2010 | 20412306 |
| characterization of strains unlike mesorhizobium loti that nodulate lotus spp. in saline soils of granada, spain. | lotus species are forage legumes with potential as pastures in low-fertility and environmentally constrained soils, owing to their high persistence and yield under those conditions. the aim of this work was the characterization of phenetic and genetic diversity of salt-tolerant bacteria able to establish efficient symbiosis with lotus spp. a total of 180 isolates able to nodulate lotus corniculatus and lotus tenuis from two locations in granada, spain, were characterized. molecular identificatio ... | 2010 | 20435777 |
| resonance assignments of the nucleotide-free wildtype mlok1 cyclic nucleotide-binding domain. | cyclic nucleotide-sensitive ion channels, known as hcn and cng channels play crucial roles in neuronal excitability and signal transduction of sensory cells. these channels are activated by binding of cyclic nucleotides to their intracellular cyclic nucleotide-binding domain (cnbd). a comparison of the structures of wildtype ligand-free and ligand-bound cnbd is essential to elucidate the mechanism underlying nucleotide-dependent activation of cnbds. we recently reported the solution structure of ... | 2010 | 20449776 |
| characterization of the nifa-rpon regulon in rhizobium etli in free life and in symbiosis with phaseolus vulgaris. | the nifa-rpon complex is a master regulator of the nitrogen fixation genes in alphaproteobacteria. based on the complete rhizobium etli genome sequence, we constructed an r. etli cfn42 oligonucleotide (70-mer) microarray and utilized this tool, reverse transcription (rt)-pcr analysis (transcriptomics), proteomics, and bioinformatics to decipher the nifa-rpon regulon under microaerobic conditions (free life) and in symbiosis with bean plants. the r. etli nifa-rpon regulon was determined to contai ... | 2010 | 20453139 |
| disruption of the glycine cleavage system enables sinorhizobium fredii usda257 to form nitrogen-fixing nodules on agronomically improved north american soybean cultivars. | the symbiosis between sinorhizobium fredii usda257 and soybean [glycine max (l.) merr.] exhibits a high degree of cultivar specificity. usda257 nodulates primitive soybean cultivars but fails to nodulate agronomically improved cultivars such as mccall. in this study we provide evidence for the involvement of a new genetic locus that controls soybean cultivar specificity. this locus was identified in usda257 by tn5 transposon mutagenesis followed by nodulation screening on mccall soybean. we have ... | 2010 | 20453144 |
| the complete genome sequence of cupriavidus metallidurans strain ch34, a master survivalist in harsh and anthropogenic environments. | many bacteria in the environment have adapted to the presence of toxic heavy metals. over the last 30 years, this heavy metal tolerance was the subject of extensive research. the bacterium cupriavidus metallidurans strain ch34, originally isolated by us in 1976 from a metal processing factory, is considered a major model organism in this field because it withstands milli-molar range concentrations of over 20 different heavy metal ions. this tolerance is mostly achieved by rapid ion efflux but al ... | 2010 | 20463976 |
| evolutionary ancestry and novel functions of the mammalian glucose transporter (glut) family. | in general, sugar porters function by proton-coupled symport or facilitative transport modes. symporters, coupled to electrochemical energy, transport nutrients against a substrate gradient. facilitative carriers transport sugars along a concentration gradient, thus transport is dependent upon extracellular nutrient levels. across bacteria, fungi, unicellular non-vertebrates and plants, proton-coupled hexose symport is a crucial process supplying energy under conditions of nutrient flux. in mamm ... | 2010 | 20487568 |
| transcriptome analysis of the mobile genome iceclc in pseudomonas knackmussii b13. | integrative and conjugative elements (ice) form a diverse group of dna elements that are integrated in the chromosome of the bacterial host, but can occasionally excise and horizontally transfer to a new host cell. ice come in different families, typically with a conserved core for functions controlling the element's behavior and a variable region providing auxiliary functions to the host. the iceclc element of pseudomonas knackmussii strain b13 is representative for a large family of chromosoma ... | 2010 | 20504315 |
| crystallization and preliminary x-ray analysis of sdr-type pyridoxal dehydrogenase from mesorhizobium loti. | pyridoxal 4-dehydrogenase from mesorhizobium loti maff303099 was overexpressed in escherichia coli. the recombinant selenomethionine-substituted enzyme was purified and crystallized by the sitting-drop vapour-diffusion method using peg 4000 as precipitant. crystals grew in the presence of 0.45 mm nad(+). the crystals diffracted to 2.9 a resolution and belonged to the monoclinic space group p2(1), with unit-cell parameters a = 86.20, b = 51.11, c = 91.73 a, beta = 89.36 degrees. the calculated v( ... | 2010 | 20516609 |
| the phosphatomes of the multicellular myxobacteria myxococcus xanthus and sorangium cellulosum in comparison with other prokaryotic genomes. | analysis of the complete genomes from the multicellular myxobacteria myxococcus xanthus and sorangium cellulosum identified the highest number of eukaryotic-like protein kinases (elks) compared to all other genomes analyzed. high numbers of protein phosphatases (pps) could therefore be anticipated, as reversible protein phosphorylation is a major regulation mechanism of fundamental biological processes. | 2010 | 20567509 |
| agrobacterium tumefaciens exor represses succinoglycan biosynthesis and is required for biofilm formation and motility. | the ubiquitous plant pathogen agrobacterium tumefaciens attaches efficiently to plant tissues and abiotic surfaces and can form complex biofilms. a genetic screen for mutants unable to form biofilms on pvc identified disruptions in a homologue of the exor gene. exor is a predicted periplasmic protein, originally identified in sinorhizobium meliloti, but widely conserved among alphaproteobacteria. disruptions in the a. tumefaciens exor gene result in severely compromised attachment to abiotic sur ... | 2010 | 20576688 |
| the bridge-region of the ku superfamily is an atypical zinc ribbon domain. | members of the ku superfamily are dna-end-binding proteins involved in non-homologous end-joining (nhej) dna repair. the published crystal structure of human ku-dna complex reveals a heterodimer that forms a ring around dsdna by means of the ku core modules. these modules contain a highly conserved seven-stranded β-barrel, which in turn contains an insertion, termed the bridge-region, between its second and third β-strands. the bridge-region adopts an unusual β-strand-rich structure critical for ... | 2010 | 20580930 |
| gene transfer into solanum tuberosum via rhizobium spp. | agrobacterium tumefaciens-mediated transformation (atmt) is the preferred technique for gene transfer into crops. a major disadvantage of the technology remains the complexity of the patent landscape that surrounds atmt which restricts its use for commercial applications. an alternative system has been described (broothaerts et al. in nature 433:629-633, 2005) detailing the propensity of three rhizobia to transform the model crop arabidopsis thaliana, the non-food crop nicotiana tabacum and, at ... | 2011 | 20582626 |
| identification of two flavin monooxygenases from an effluent treatment plant sludge metagenomic library. | oxygenases are useful for the production of many industrially important molecules. screening of an effluent treatment plant (etp) sludge metagenomic library identified two clones encoding proteins, b1 and b2, with similarity to putative flavin monooxygenases from mesorhizobium loti and sphingomonas wittichi, respectively. the deduced amino acid sequences show only 20% identity, but both have a paired rossman fold and a flavin monooxygenase (fmo) motif. b1 and b2 appear to be members of the flavi ... | 2010 | 20591656 |
| a cell-type-specific protein-protein interaction modulates transcriptional activity of a master regulator in caulobacter crescentus. | progression through the caulobacter cell cycle is driven by the master regulator ctra, an essential two-component signaling protein that regulates the expression of nearly 100 genes. ctra is abundant throughout the cell cycle except immediately prior to dna replication. however, the expression of ctra-activated genes is generally restricted to s phase. we identify the conserved protein scip (small ctra inhibitory protein) and show that it accumulates during g1, where it inhibits ctra from activa ... | 2010 | 20598601 |
| an alternative route for udp-diacylglucosamine hydrolysis in bacterial lipid a biosynthesis. | the outer leaflet of the outer membranes of gram-negative bacteria is composed primarily of lipid a, the hydrophobic anchor of lipopolysaccharide. like escherichia coli, most gram-negative bacteria encode one copy of each of the nine genes required for lipid a biosynthesis. an important exception exists in the case of the fourth enzyme, lpxh, a peripheral membrane protein that hydrolyzes udp-2,3-diacylglucosamine to form 2,3-diacylglucosamine 1-phosphate and ump by catalyzing the attack of water ... | 2010 | 20608695 |
| inhibitory effect on the tobacco mosaic virus infection by a plant ring finger protein. | in the yeast two-hybrid screening of plant factors interacting with tobacco mosaic virus (tmv) rna-dependent rna polymerase (rdrp), we found a protein containing a ring finger motif in tobacco (nicotiana tabacum) and designated it as tarf (tmv-associated ring finger protein). tarf is a homologue of a lotus japonicus ring finger protein (ljnsring) involved in the symbiotic interaction between l. japonicus and mesorhizobium loti. when tarf was silenced by virus-induced gene silencing (vigs) method ... | 2010 | 20621138 |
| biosynthesis of compatible solutes in rhizobial strains isolated from phaseolus vulgaris nodules in tunisian fields. | associated with appropriate crop and soil management, inoculation of legumes with microbial biofertilizers can improve food legume yield and soil fertility and reduce pollution by inorganic fertilizers. rhizospheric bacteria are subjected to osmotic stress imposed by drought and/or nacl, two abiotic constraints frequently found in semi-arid lands. osmostress response in bacteria involves the accumulation of small organic compounds called compatible solutes. whereas most studies on rhizobial osmo ... | 2010 | 20633304 |
| the omptins of yersinia pestis and salmonella enterica cleave the reactive center loop of plasminogen activator inhibitor 1. | plasminogen activator inhibitor 1 (pai-1) is a serine protease inhibitor (serpin) and a key molecule that regulates fibrinolysis by inactivating human plasminogen activators. here we show that two important human pathogens, the plague bacterium yersinia pestis and the enteropathogen salmonella enterica serovar typhimurium, inactivate pai-1 by cleaving the r346-m347 bait peptide bond in the reactive center loop. no cleavage of pai-1 was detected with yersinia pseudotuberculosis, an oral/fecal pat ... | 2010 | 20639337 |
| cloning-independent expression and analysis of omega-transaminases by use of a cell-free protein synthesis system. | herewith we report the expression and screening of microbial enzymes without involving cloning procedures. computationally predicted putative omega-transaminase (omega-ta) genes were pcr amplified from the bacterial colonies and expressed in a cell-free protein synthesis system for subsequent analysis of their enzymatic activity and substrate specificity. through the cell-free expression analysis of the putative omega-ta genes, a number of enzyme-substrate pairs were identified in a matter of ho ... | 2010 | 20656866 |
| how many peas in a pod? legume genes responsible for mutualistic symbioses underground. | the nitrogen-fixing symbiosis between legume plants and rhizobium bacteria is the most prominent plant-microbe endosymbiotic system and, together with mycorrhizal fungi, has critical importance in agriculture. the introduction of two model legume species, lotus japonicus and medicago truncatula, has enabled us to identify a number of host legume genes required for symbiosis. a total of 26 genes have so far been cloned from various symbiotic mutants of these model legumes, which are involved in r ... | 2010 | 20660226 |
| a new family of enzymes catalyzing the first committed step of the methylerythritol 4-phosphate (mep) pathway for isoprenoid biosynthesis in bacteria. | isoprenoids are a large family of compounds with essential functions in all domains of life. most eubacteria synthesize their isoprenoids using the methylerythritol 4-phosphate (mep) pathway, whereas a minority uses the unrelated mevalonate pathway and only a few have both. interestingly, brucella abortus and some other bacteria that only use the mep pathway lack deoxyxylulose 5-phosphate (dxp) reductoisomerase (dxr), the enzyme catalyzing the nadph-dependent production of mep from dxp in the fi ... | 2010 | 20660776 |
| the baca gene homolog, mlr7400, in mesorhizobium loti maff303099 is dispensable for symbiosis with lotus japonicus but partially capable of supporting the symbiotic function of baca in sinorhizobium meliloti. | establishment of rhizobium-legume symbiosis requires a series of mutual authentication, which might involve bacterial evasion of host defense. one such evasion-related genes is sinorhizobium meliloti baca that is essential for bacteroid formation. baca is a transmembrane protein highly similar to escherichia coli sbma, a predicted transporter, and has homologs even in animal pathogens, such as brucella abortus in which the homolog contributes to effective survival in host macrophages. despite su ... | 2010 | 20668224 |
| evolutionary dynamics of insertion sequences in relation to the evolutionary histories of the chromosome and symbiotic plasmid genes of rhizobium etli populations. | insertion sequences (is) are mobile genetic elements that are distributed in many prokaryotes. in particular, in the genomes of the symbiotic nitrogen-fixing bacteria collectively known as rhizobia, is are fairly abundant in plasmids or chromosomal islands that carry the genes needed for symbiosis. here, we report an analysis of the distribution and genetic conservation of the is found in the genome of rhizobium etli cfn42 in a collection of 87 rhizobium strains belonging to populations with dif ... | 2010 | 20675442 |
| nena, a lotus japonicus homolog of sec13, is required for rhizodermal infection by arbuscular mycorrhiza fungi and rhizobia but dispensable for cortical endosymbiotic development. | legumes form symbioses with arbuscular mycorrhiza (am) fungi and nitrogen fixing root nodule bacteria. intracellular root infection by either endosymbiont is controlled by the activation of the calcium and calmodulin-dependent kinase (ccamk), a central regulatory component of the plant's common symbiosis signaling network. we performed a microscopy screen for lotus japonicus mutants defective in am development and isolated a mutant, nena, that aborted fungal infection in the rhizodermis. nena en ... | 2010 | 20675572 |
| predicted class-i aminoacyl trna synthetase-like proteins in non-ribosomal peptide synthesis. | recent studies point to a great diversity of non-ribosomal peptide synthesis systems with major roles in amino acid and co-factor biosynthesis, secondary metabolism, and post-translational modifications of proteins by peptide tags. the least studied of these systems are those utilizing trnas or aminoacyl-trna synthetases (aatrs) in non-ribosomal peptide ligation. | 2010 | 20678224 |
| intergenic transposable elements are not randomly distributed in bacteria. | insertion sequences (iss) are mobile genetic elements in bacterial genomes. in general, intergenic is elements are probably less deleterious for their hosts than intragenic iss, simply because they have a lower likelihood of disrupting native genes. however, since promoters, shine-dalgarno sequences, and transcription factor binding sites are intergenic and upstream of genes, i hypothesized that not all neighboring gene orientations (ngos) are selectively equivalent for is insertion. to test thi ... | 2010 | 20697140 |
| a suite of lotus japonicus starch mutants reveals both conserved and novel features of starch metabolism. | the metabolism of starch is of central importance for many aspects of plant growth and development. information on leaf starch metabolism other than in arabidopsis (arabidopsis thaliana) is scarce. furthermore, its importance in several agronomically important traits exemplified by legumes remains to be investigated. to address this issue, we have provided detailed information on the genes involved in starch metabolism in lotus japonicus and have characterized a comprehensive collection of forwa ... | 2010 | 20699404 |
| structure and functional analysis of lptc, a conserved membrane protein involved in the lipopolysaccharide export pathway in escherichia coli. | lptc is a conserved bitopic inner membrane protein from escherichia coli involved in the export of lipopolysaccharide from its site of synthesis in the cytoplasmic membrane to the outer membrane. lptc forms a complex with the atp-binding cassette transporter, lptbfg, which is thought to facilitate the extraction of lipopolysaccharide from the inner membrane and release it into a translocation pathway that includes the putative periplasmic chaperone lpta. cysteine modification experiments establi ... | 2010 | 20720015 |
| a structural model of anti-anti-σ inhibition by a two-component receiver domain: the phyr stress response regulator. | phyr is a hybrid stress regulator conserved in α-proteobacteria that contains an n-terminal σ-like (sl) domain and a c-terminal receiver domain. phosphorylation of the receiver domain is known to promote binding of the sl domain to an anti-σ factor. phyr thus functions as an anti-anti-σ factor in its phosphorylated state. we present genetic evidence that caulobacter crescentus phyr is a phosphorylation-dependent stress regulator that functions in the same pathway as σ(t) and its anti-σ factor, n ... | 2010 | 20735776 |
| protein networks reveal detection bias and species consistency when analysed by information-theoretic methods. | we apply our recently developed information-theoretic measures for the characterisation and comparison of protein-protein interaction networks. these measures are used to quantify topological network features via macroscopic statistical properties. network differences are assessed based on these macroscopic properties as opposed to microscopic overlap, homology information or motif occurrences. we present the results of a large-scale analysis of protein-protein interaction networks. precise null ... | 2010 | 20805870 |
| characterization of a two-component regulatory system that regulates succinate-mediated catabolite repression in sinorhizobium meliloti. | when they are available, sinorhizobium meliloti utilizes c(4)-dicarboxylic acids as preferred carbon sources for growth while suppressing the utilization of some secondary carbon sources such as α- and β-galactosides. the phenomenon of using succinate as the sole carbon source in the presence of secondary carbon sources is termed succinate-mediated catabolite repression (smcr). genetic screening identified the gene sma0113 as needed for strong smcr when s. meliloti was grown in succinate plus la ... | 2010 | 20817764 |
| symbiotic legume nodules employ both rhizobial exo- and endo-hydrogenases to recycle hydrogen produced by nitrogen fixation. | in symbiotic legume nodules, endosymbiotic rhizobia (bacteroids) fix atmospheric n(2), an atp-dependent catalytic process yielding stoichiometric ammonium and hydrogen gas (h(2)). while in most legume nodules this h(2) is quantitatively evolved, which loss drains metabolic energy, certain bacteroid strains employ uptake hydrogenase activity and thus evolve little or no h(2). rather, endogenous h(2) is efficiently respired at the expense of o(2), driving oxidative phosphorylation, recouping atp u ... | 2010 | 20838423 |
| structure and mechanism of orf36, an amino sugar oxidizing enzyme in everninomicin biosynthesis . | everninomicin is a highly modified octasaccharide that belongs to the orthosomycin family of antibiotics and possesses potent gram-positive antibiotic activity, including broad-spectrum efficacy against multidrug resistant enterococci and staphylococcus aureus. among its distinctive structural features is a nitro sugar, l-evernitrose, analogues of which decorate a variety of natural products. recently, we identified a nitrososynthase enzyme encoded by orf36 from micromonospora carbonacea var. af ... | 2010 | 20866105 |
| role of lupeol synthase in lotus japonicus nodule formation. | • triterpenes are plant secondary metabolites, derived from the cyclization of 2,3-oxidosqualene by oxidosqualene cyclases (oscs). here, we investigated the role of lupeol synthase, encoded by osc3, and its product, lupeol, in developing roots and nodules of the model legume lotus japonicus. • the expression patterns of osc3 in different developmental stages of uninfected roots and in roots infected with mesorhizobium loti were determined. the tissue specificity of osc3 expression was analysed b ... | 2010 | 20868395 |
| r gene-controlled host specificity in the legume-rhizobia symbiosis. | leguminous plants can enter into root nodule symbioses with nitrogen-fixing soil bacteria known as rhizobia. an intriguing but still poorly understood property of the symbiosis is its host specificity, which is controlled at multiple levels involving both rhizobial and host genes. it is widely believed that the host specificity is determined by specific recognition of bacterially derived nod factors by the cognate host receptor(s). here we describe the positional cloning of two soybean genes rj2 ... | 2010 | 20937853 |
| engineered acc deaminase-expressing free-living cells of mesorhizobium loti show increased nodulation efficiency and competitiveness on lotus spp. | ethylene inhibits the establishment of symbiosis between rhizobia and legumes. several rhizobia species express the enzyme acc deaminase, which degrades the ethylene precursor 1-cyclopropane-1-carboxilate (acc), leading to reductions in the amount of ethylene evolved by the plant. m. loti has a gene encoding acc deaminase, but this gene is under the activity of the nifa-rpon-dependent promoter; thus, it is only expressed inside the nodule. the m. loti structural gene acc deaminase (acds) was int ... | 2010 | 20953097 |
| the role of sigma factor rpoh1 in the ph stress response of sinorhizobium meliloti. | environmental ph stress constitutes a limiting factor for s. meliloti survival and development. the response to acidic ph stress in s. meliloti is versatile and characterized by the differential expression of genes associated with various cellular functions. the purpose of this study was to gain detailed insight into the participation of sigma factors in the complex stress response system of s. meliloti 1021 using ph stress as an effector. | 2010 | 20955556 |
| the molecular network governing nodule organogenesis and infection in the model legume lotus japonicus. | bacterial infection of interior tissues of legume root nodules is controlled at the epidermal cell layer and is closely coordinated with progressing organ development. using spontaneous nodulating lotus japonicus plant mutants to uncouple nodule organogenesis from infection, we have determined the role of 16 genes in these two developmental processes. we show that host-encoded mechanisms control three alternative entry processes operating in the epidermis, the root cortex and at the single cell ... | 2010 | 20975672 |
| networks of gene sharing among 329 proteobacterial genomes reveal differences in lateral gene transfer frequency at different phylogenetic depths. | lateral gene transfer (lgt) is an important mechanism of natural variation among prokaryotes. over the full course of evolution, most or all of the genes resident in a given prokaryotic genome have been affected by lgt, yet the frequency of lgt can vary greatly across genes and across prokaryotic groups. the proteobacteria are among the most diverse of prokaryotic taxa. the prevalence of lgt in their genome evolution calls for the application of network-based methods instead of tree-based method ... | 2010 | 21059789 |
| networks of gene sharing among 329 proteobacterial genomes reveal differences in lateral gene transfer frequency at different phylogenetic depths. | lateral gene transfer (lgt) is an important mechanism of natural variation among prokaryotes. over the full course of evolution, most or all of the genes resident in a given prokaryotic genome have been affected by lgt, yet the frequency of lgt can vary greatly across genes and across prokaryotic groups. the proteobacteria are among the most diverse of prokaryotic taxa. the prevalence of lgt in their genome evolution calls for the application of network-based methods instead of tree-based method ... | 2010 | 21059789 |
| argc orthologs from rhizobiales show diverse profiles of transcriptional efficiency and functionality in sinorhizobium meliloti. | several factors can influence ortholog replacement between closely related species. we evaluated the transcriptional expression and metabolic performance of ortholog substitution complementing a sinorhizobium meliloti argc mutant with argc from rhizobiales (agrobacterium tumefaciens, rhizobium etli, and mesorhizobium loti). the argc gene is necessary for the synthesis of arginine, an amino acid that is central to protein and cellular metabolism. strains were obtained carrying plasmids with argc ... | 2010 | 21075924 |
| argc orthologs from rhizobiales show diverse profiles of transcriptional efficiency and functionality in sinorhizobium meliloti. | several factors can influence ortholog replacement between closely related species. we evaluated the transcriptional expression and metabolic performance of ortholog substitution complementing a sinorhizobium meliloti argc mutant with argc from rhizobiales (agrobacterium tumefaciens, rhizobium etli, and mesorhizobium loti). the argc gene is necessary for the synthesis of arginine, an amino acid that is central to protein and cellular metabolism. strains were obtained carrying plasmids with argc ... | 2010 | 21075924 |
| annotation and structural analysis of sialylated human milk oligosaccharides. | sialylated human milk oligosaccharides (shmos) are important components of human milk oligosaccharides. sialic acids are typically found on the nonreducing end and are known binding sites for pathogens and aid in neonates' brain development. due to their negative charge and hydrophilic nature, they also help modulate cell-cell interactions. it has also been shown that sialic acids are involved in regulating the immune response and aid in brain development. in this study, the enriched shmos from ... | 2011 | 21133381 |
| a c subunit of the plant nuclear factor nf-y required for rhizobial infection and nodule development affects partner selection in the common bean-rhizobium etli symbiosis. | legume plants are able to interact symbiotically with soil bacteria to form nitrogen-fixing root nodules. although specific recognition between rhizobia and legume species has been extensively characterized, plant molecular determinants that govern the preferential colonization by different strains within a single rhizobium species have received little attention. we found that the c subunit of the heterotrimeric nuclear factor nf-y from common bean (phaseolus vulgaris) nf-yc1 plays a key role in ... | 2010 | 21139064 |