Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| both plant and bacterial nitrate reductases contribute to nitric oxide production in medicago truncatula nitrogen-fixing nodules. | nitric oxide (no) is a signaling and defense molecule of major importance in living organisms. in the model legume medicago truncatula, no production has been detected in the nitrogen fixation zone of the nodule, but the systems responsible for its synthesis are yet unknown and its role in symbiosis is far from being elucidated. in this work, using pharmacological and genetic approaches, we explored the enzymatic source of no production in m. truncatula-sinorhizobium meliloti nodules under normo ... | 2010 | 21139086 |
| both plant and bacterial nitrate reductases contribute to nitric oxide production in medicago truncatula nitrogen-fixing nodules. | nitric oxide (no) is a signaling and defense molecule of major importance in living organisms. in the model legume medicago truncatula, no production has been detected in the nitrogen fixation zone of the nodule, but the systems responsible for its synthesis are yet unknown and its role in symbiosis is far from being elucidated. in this work, using pharmacological and genetic approaches, we explored the enzymatic source of no production in m. truncatula-sinorhizobium meliloti nodules under normo ... | 2010 | 21139086 |
| a novel interaction between ccamk and a protein containing the scythe_n ubiquitin-like domain in lotus japonicus. | in the rhizobium-legume symbiosis, calcium/calmodulin-dependent protein kinase (ccamk) is a key regulator for both rhizobial infection and nodule organogenesis. deregulation of ccamk by either a point mutation in the autophosphorylation site or the deletion of the carboxyl-terminal regulatory domain results in spontaneous nodule formation without rhizobia. however, the underlying biochemical mechanisms are poorly understood. here, using the kinase domain of ccamk as a bait in yeast two-hybrid sc ... | 2011 | 21209278 |
| cyclic gmp controls rhodospirillum centenum cyst development. | adenylyl cyclases are widely distributed across all kingdoms whereas guanylyl cyclases are generally thought to be restricted to eukaryotes. here we report that the α-proteobacterium rhodospirillum centenum secretes cgmp when developing cysts and that a guanylyl cyclase deletion strain fails to synthesize cgmp and is defective in cyst formation. the r. centenum cyclase was purified and shown to effectively synthesize cgmp from gtp in vitro, demonstrating that it is a functional guanylyl cyclase. ... | 2011 | 21214648 |
| from defense to symbiosis: limited alterations in the kinase domain of lysm receptor-like kinases are crucial for evolution of legume-rhizobium symbiosis. | nitrogen-fixing symbiosis between legumes and rhizobia is initiated by the recognition of rhizobial nod factors (nfs) by host plants. nfs are diversely modified derivatives of chitin oligosaccharide, a fungal elicitor that induces defense responses in plants. recent evidence has shown that both nfs and chitin elicitors are recognized by structurally related lysm receptor kinases. transcriptome analyses of lotus japonicus roots indicated that nfs not only activate symbiosis genes but also transie ... | 2010 | 21223383 |
| a processive glycosyltransferase involved in glycolipid synthesis during phosphate deprivation in mesorhizobium loti. | natural habitats are often characterized by a low availability of phosphate. in plants and many bacteria, phosphate deficiency causes different physiological responses, including the replacement of phosphoglycerolipids in the membranes with nonphosphorous lipids. we describe here a processive glycosyltransferase (pgt) in mesorhizobium loti (rhizobiales) involved in the synthesis of di- and triglycosyldiacylglycerols (dglycd and tglycd) during phosphate deprivation. cells of the corresponding δpg ... | 2011 | 21239587 |
| characterization of two novel nodule-enhanced α-type carbonic anhydrases from lotus japonicus. | two cdna clones coding for α-type carbonic anhydrases (ca; ec 4.2.1.1) in the nitrogen-fixing nodules of the model legume lotus japonicus were identified. functionality of the full-length proteins was confirmed by heterologous expression in escherichia coli and purification of the encoded polypeptides. the developmental expression pattern of ljcaa1 and ljcaa2 revealed that both genes code for nodule enhanced carbonic anhydrase isoforms, which are induced early during nodule development. the gene ... | 2011 | 21256984 |
| two novel classes of enzymes are required for the biosynthesis of aurofusarin in fusarium graminearum. | previous studies have reported the functional characterization of 9 out of 11 genes found in the gene cluster responsible for biosynthesis of the polyketide pigment aurofusarin in fusarium graminearum. here we reanalyze the function of a putative aurofusarin pump (aurt) and the two remaining orphan genes, aurz and aurs. targeted gene replacement of aurz resulted in the discovery that the compound ywa1, rather than nor-rubrofusarin, is the primary product of f. graminearum polyketide synthase 12 ... | 2011 | 21296881 |
| nodulation enhances dark co2 fixation and recycling in the model legume lotus japonicus. | during symbiotic nitrogen fixation (snf), the nodule becomes a strong sink for photosynthetic carbon. here, it was studied whether nodule dark co(2) fixation could participate in a mechanism for co(2) recycling through c(4)-type photosynthesis. differences in the natural d(13)c abundance between lotus japonicus inoculated or not with the n-fixing mesorhizobium loti were assessed. (13)c labelling and gene expression of key enzymes of co(2) metabolism were applied in plants inoculated with wild-ty ... | 2011 | 21307384 |
| the crystal structure of sdr-type pyridoxal 4-dehydrogenase of mesorhizobium loti. | pyridoxal 4-dehydrogenase catalyzes the irreversible oxidation of pyridoxal to 4-pyridoxolactone and is involved in degradation pathway i of pyridoxine, a vitamin b(6) compound. its crystal structure was elucidated for the first time. molecular replacement with (s)-1-phenylthanol dehydrogenase (pdb code 2ew8) was adopted to determine the tertiary structure of the nad(+)-bound enzyme. | 2011 | 21307574 |
| mining high-throughput experimental data to link gene and function. | nearly 2200 genomes that encode around 6 million proteins have now been sequenced. around 40% of these proteins are of unknown function, even when function is loosely and minimally defined as 'belonging to a superfamily'. in addition to in silico methods, the swelling stream of high-throughput experimental data can give valuable clues for linking these unknowns with precise biological roles. the goal is to develop integrative data-mining platforms that allow the scientific community at large to ... | 2011 | 21310501 |
| interaction of diverse voltage sensor homologs with lipid bilayers revealed by self-assembly simulations. | voltage sensors (vs) domains couple the activation of ion channels/enzymes to changes in membrane voltage. we used molecular dynamics simulations to examine interactions with lipids of several vs homologs. vss in intact channels in the activated state are exposed to phospholipids, leading to a characteristic local distortion of the lipid bilayer which decreases its thickness by ∼10 å. this effect is mediated by a conserved hydrophilic stretch in the s4-s5 segment linking the vs and the pore doma ... | 2011 | 21320431 |
| nitric oxide production induced in roots of lotus japonicus by lipopolysaccharide from mesorhizobium loti. | lipopolysaccharide (lps) is a bacterial molecule that induces nitric oxide (no) production and triggers defense systems in plant-pathogen interactions. no production is induced in the roots of lotus japonicus after inoculation of the roots with its microsymbiont mesorhizobium loti. however, the rhizobial molecule that induces no production has not yet been identified. we investigated no production in the roots of l. japonicus by treatment with lps of m. loti. lps was prepared by phenol-hot water ... | 2011 | 21330297 |
| distribution of genes encoding nucleoid-associated protein homologs in plasmids. | bacterial nucleoid-associated proteins (naps) form nucleoprotein complexes and influence the expression of genes. recent studies have shown that some plasmids carry genes encoding nap homologs, which play important roles in transcriptional regulation networks between plasmids and host chromosomes. in this study, we determined the distributions of the well-known naps fis, h-ns, hu, ihf, and lrp and the newly found naps mvat and ndpa among the whole-sequenced 1382 plasmids found in gram-negative b ... | 2011 | 21350637 |
| role of baca in lipopolysaccharide synthesis, peptide transport, and nodulation by rhizobium sp. strain ngr234. | baca of sinorhizobium meliloti plays an essential role in the establishment of nitrogen-fixing symbioses with medicago plants, where it is involved in peptide import and in the addition of very-long-chain fatty acids (vlcfa) to lipid a of lipopolysaccharide (lps). we investigated the role of baca in rhizobium species strain ngr234 by mutating the baca gene. in the ngr234 baca mutant, peptide import was impaired, but no effect on vlcfa addition was observed. more importantly, the symbiotic abilit ... | 2011 | 21357487 |
| structural insights into conformational changes of a cyclic nucleotide-binding domain in solution from mesorhizobium loti k1 channel. | cyclic nucleotide-sensitive ion channels, known as hcn and cng channels, are activated by binding of ligands to a domain (cnbd) located on the cytoplasmic side of the channel. the underlying mechanisms are not well understood. to elucidate the gating mechanism, structures of both the ligand-free and -bound cnbd are required. several crystal structures of the cnbd from hcn2 and a bacterial cng channel (mlok1) have been solved. however, for hcn2, the camp-free and -bound state did not reveal subst ... | 2011 | 21430265 |
| nitric oxide is required for an optimal establishment of the medicago truncatula-sinorhizobium meliloti symbiosis. | nitric oxide (no) is a gaseous molecule that participates in numerous plant signalling pathways. it is involved in plant responses to pathogens and development processes such as seed germination, flowering and stomatal closure. using a permeable no-specific fluorescent probe and a bacterial reporter strain expressing the lacz gene under the control of a no-responsive promoter, we detected no production in the first steps, during infection threads growth, of the medicago truncatula-sinorhizobium ... | 2011 | 21457261 |
| housekeeping genes essential for pantothenate biosynthesis are plasmid-encoded in rhizobium etli and rhizobium leguminosarum. | a traditional concept in bacterial genetics states that housekeeping genes, those involved in basic metabolic functions needed for maintenance of the cell, are encoded in the chromosome, whereas genes required for dealing with challenging environmental conditions are located in plasmids. exceptions to this rule have emerged from genomic sequence data of bacteria with multipartite genomes. the genome sequence of r. etli cfn42 predicts the presence of panc and panb genes clustered together on the ... | 2011 | 21463532 |
| competing formate- and carbon dioxide-utilizing prokaryotes in an anoxic methane-emitting fen soil. | methanogenesis in wetlands is dependent on intermediary substrates derived from the degradation of biopolymers. formate is one such substrate and is stimulatory to methanogenesis and acetogenesis in anoxic microcosms of soil from the fen schlöppnerbrunnen. formate dissimilation also yields co(2) as a potential secondary substrate. the objective of this study was to resolve potential differences between anaerobic formate- and co(2)-utilizing prokaryotes of this fen by stable isotope probing. anox ... | 2011 | 21478308 |
| genetic diversity of root nodule bacteria nodulating lotus corniculatus and anthyllis vulneraria in sweden. | very little is known about the genetic diversity and phylogeny of rhizobia nodulating lotus species in northern temperate regions. we have therefore studied the genetic diversity among a total of 61 root nodule bacteria isolated from lotus corniculatus and anthyllis vulneraria from different geographic sites and habitats in sweden by restriction fragment length polymorphism (rflp) of the internal transcribed spacer between their 16s rrna and 23s rrna (igs) region. a high diversity consisting of ... | 2011 | 21497473 |
| identification of mesorhizobium loti genes relevant to symbiosis by using signature-tagged mutants. | signature-tagged mutagenesis was applied to mesorhizobium loti, a nitrogen-fixing root-nodule symbiont of the leguminous plant lotus japonicus. we arranged 1,887 non-redundant mutant strains of m. loti into 75 sets, each consisting of 24 to 26 strains with a different tag in each strain. these sets were each inoculated en masse onto l. japonicus plants. comparative analysis of total dna extracted from inoculants and resulting nodules based on quantitative pcr led to the selection of 69 strains a ... | 2011 | 21502733 |
| plant growth-promoting fungus, trichoderma koningi suppresses isoflavonoid phytoalexin vestitol production for colonization on/in the roots of lotus japonicus. | the relationship between the colonization of lotus japonicus by plant growth-promoting fungi (pgpf) and biosynthesis of the isoflavonoid phytoalexin vestitol, a major defensive response of leguminous plants, was analyzed. when pgpf including trichoderma koningi, fusarium equiseti, and penicillium simplicissimum were inoculated onto l. japonicus roots, only t. koningi colonized the roots long-term and increased plant dry weight (126%). microscopic observations of transverse sections of roots colo ... | 2011 | 21502738 |
| bioinformatic characterization of the trimeric intracellular cation-specific channel protein family. | trimeric intracellular cation-specific (tric) channels are integral to muscle excitation-contraction coupling. tric channels provide counter-ionic flux when calcium is rapidly transported from intracellular stores to the cell cytoplasm. until recently, knowledge of the presence of these proteins was limited to animals. we analyzed the tric family and identified a profusion of prokaryotic family members with topologies and motifs similar to those of their eukaryotic counterparts. prokaryotic memb ... | 2011 | 21519847 |
| proteinortho: detection of (co-)orthologs in large-scale analysis. | orthology analysis is an important part of data analysis in many areas of bioinformatics such as comparative genomics and molecular phylogenetics. the ever-increasing flood of sequence data, and hence the rapidly increasing number of genomes that can be compared simultaneously, calls for efficient software tools as brute-force approaches with quadratic memory requirements become infeasible in practise. the rapid pace at which new data become available, furthermore, makes it desirable to compute ... | 2011 | 21526987 |
| isolation of xylose isomerases by sequence- and function-based screening from a soil metagenome library. | abstract: background: xylose isomerase (xi) catalyses the isomerization of xylose to xylulose in bacteria and some fungi. currently, only a limited number of xi genes have been functionally expressed in saccharomyces cerevisiae, the microorganism of choice for lignocellulosic ethanol production. the objective of the present study was to search for novel xi genes in the vastly diverse microbial habitat present in soil. as the exploitation of microbial diversity is impaired by the ability to culti ... | 2011 | 21545702 |
| evolution of abscisic acid synthesis and signaling mechanisms. | the plant hormone abscisic acid (aba) mediates seed dormancy, controls seedling development and triggers tolerance to abiotic stresses, including drought. core aba signaling components consist of a recently identified group of aba receptor proteins of the pyrabactin resistance (pyr)/regulatory component of aba receptor (rcar) family that act as negative regulators of members of the protein phosphatase 2c (pp2c) family. inhibition of pp2c activity enables activation of snf1-related kinase 2 (snrk ... | 2011 | 21549957 |
| peroxiredoxins and nadph-dependent thioredoxin systems in the model legume lotus japonicus. | peroxiredoxins (prxs), thioredoxins (trxs), and nadph-thioredoxin reductases (ntrs) constitute central elements of the thiol-disulfide redox regulatory network of plant cells. this study provides a comprehensive survey of this network in the model legume lotus japonicus. the aims were to identify and characterize these gene families and to assess whether the ntr-trx systems are operative in nodules. quantitative reverse transcription-polymerase chain reaction and immunological and proteomic appr ... | 2011 | 21562331 |
| root hair deformation of symbiosis-deficient mutants of lotus japonicus by application of nod factor from mesorhizobium loti. | in the model leguminous plant lotus japonicus, the reception of a symbiotic signal called nod factor (nf), which is secreted by the symbiont bacterium mesorhizobium loti, induces wavy shaped root hairs. this is called root hair deformation. to dissect the root hair deformation process, we studied symbiosis- deficient mutants of l. japonicus, castor, nup85, ccamk and nsp2. the castor, nup85, and ccamk genes are also required for mycorrhizal infection and thus called common symbiotic genes. on the ... | 2009 | 21566365 |
| azorhirobial chromosome partition gene (para) is involved in the onset of bacteroid differentiation in sesbania rostrata stem-nodule development. | a para gene in-frame deletion mutant of azorhizobium caulinodans ors571 (ors571-δpara) was constructed to evaluate the roles of the chromosome partitioning gene on various bacterial traits and on the development of stem-positioned nodules. the δpara mutant showed a pleiomorphic cell shape phenotype, and was polyploidy with differences in nucleoid sizes due to dramatic defects in chromosome partitioning. upon inoculating the δpara mutant onto the stem of sesbania rostrata, three types of immature ... | 2011 | 21571889 |
| tonb-dependent receptors in nitrogen-fixing nodulating bacteria. | tonb-dependent receptors (tbdrs) allow gram-negative bacteria to uptake scarce resources from competitive environments with very high affinity. early reports on tbdrs focused on the uptake of siderophore-iron complexes but recent studies have showed that the spectrum of ligands includes sugars, vitamins, heme, and other non-ferrous cations. to investigate the possible roles of tbdrs in nitrogen-fixing, nodulating bacteria, a bioinformatics approach was adopted to identify their presence in the g ... | 2010 | 21576856 |
| characterization of mesorhizobium loti l-rhamnose isomerase and its application to l-talose production. | the l-rhamnose isomerase gene (rhi) of mesorhizobium loti was cloned and expressed in escherichia coli, and then characterized. the enzyme exhibited activity with respect to various aldoses, including d-allose and l-talose. application of it in l-talose production from galactitol was achieved by a two-step reaction, indicating that it can be utilized in the large-scale production of l-talose. | 2011 | 21597169 |
| s-adenosylmethionine-binding properties of a bacterial phospholipid n-methyltransferase. | the presence of the membrane lipid phosphatidylcholine (pc) in the bacterial membrane is critically important for many host-microbe interactions. the phospholipid n-methyltransferase pmta from the plant pathogen agrobacterium tumefaciens catalyzes the formation of pc by a three-step methylation of phosphatidylethanolamine via monomethyl-phosphatidylethanolamine and dimethylphosphatidylethanolamine. the methyl group is provided by s-adenosylmethionine (sam), which is converted to s-adenosylhomocy ... | 2011 | 21602340 |
| crystal structure of a novel esterase rv0045c from mycobacterium tuberculosis. | there are at least 250 enzymes in mycobacterium tuberculosis (m. tuberculosis) involved in lipid metabolism. some of the enzymes are required for bacterial survival and full virulence. the esterase rv0045c shares little amino acid sequence similarity with other members of the esterase/lipase family. here, we report the 3d structure of rv0045c. our studies demonstrated that rv0045c is a novel member of α/β hydrolase fold family. the structure of esterase rv0045c contains two distinct domains: the ... | 2011 | 21637775 |
| multiple loci are involved in quorum quenching of autoinducer i molecules in the nitrogen-fixing symbiont (sino-) rhizobium sp. ngr234. | rhizobium sp. ngr234 is a unique α-proteobacterium (order - rhizobiales) that forms nitrogen-fixing nodules with more legumes than any other micro-symbiont. since we have previously described the complete genome sequence of ngr234, we now report on a genome wide functional analysis of the genes and enzymes involved in autoinducer i hydrolysis in this microbe. altogether we identified five cosmid clones that repeatedly gave a positive result in our function-based approach for the detection of aut ... | 2011 | 21642401 |
| identification of xanthomonas fragariae, xanthomonas axonopodis pv. phaseoli, and xanthomonas fuscans subsp. fuscans with novel markers and using a dot blot platform coupled with automatic data analysis. | phytosanitary regulations and the provision of plant health certificates still rely mainly on long and laborious culture-based methods of diagnosis, which are frequently inconclusive. dna-based methods of detection can circumvent many of the limitations of currently used screening methods, allowing a fast and accurate monitoring of samples. the genus xanthomonas includes 13 phytopathogenic quarantine organisms for which improved methods of diagnosis are needed. in this work, we propose 21 new xa ... | 2011 | 21705524 |
| a monogalactosyldiacylglycerol synthase found in the green sulfur bacterium chlorobaculum tepidum reveals important roles for galactolipids in photosynthesis. | monogalactosyldiacylglycerol (mgdg), which is conserved in almost all photosynthetic organisms, is the most abundant natural polar lipid on earth. in plants, mgdg is highly accumulated in the chloroplast membranes and is an important bulk constituent of thylakoid membranes. however, precise functions of mgdg in photosynthesis have not been well understood. here, we report a novel mgdg synthase from the green sulfur bacterium chlorobaculum tepidum. this enzyme, mgda, catalyzes mgdg synthesis usin ... | 2011 | 21764989 |
| systems biology of bacterial nitrogen fixation: high-throughput technology and its integrative description with constraint-based modeling. | abstract: background: bacterial nitrogen fixation is the biological process by which atmospheric nitrogen is uptaken by bacteroids located in plant root nodules and converted into ammonium through the enzymatic activity of nitrogenase. in practice, this biological process serves as a natural form of fertilization and its optimization has significant implications in sustainable agricultural programs. currently, the advent of high-throughput technology supplies with valuable data that contribute t ... | 2011 | 21801415 |
| phylogenetic analysis reveals gene conversions in multigene families of rhizobia. | gene families are an important and intrinsic trait of rhizobial species. these gene copies can participate in non-reciprocal recombination events, also called gene conversions. gene conversion has diverse roles, but it is usually implicated in the evolution of multigene families. here, we searched for gene conversions in multigene families of six representative rhizobial genomes. we identified 11 gene families with different numbers of copies, genome location and function in cfn42 and ciat652 st ... | 2011 | 21823087 |
| bacterial community assembly based on functional genes rather than species. | the principles underlying the assembly and structure of complex microbial communities are an issue of long-standing concern to the field of microbial ecology. we previously analyzed the community membership of bacterial communities associated with the green macroalga ulva australis, and proposed a competitive lottery model for colonization of the algal surface in an attempt to explain the surprising lack of similarity in species composition across different algal samples. here we extend the prev ... | 2011 | 21825123 |
| expression and characterization of a mycoplasma genitalium glycosyltransferase in membrane glycolipid biosynthesis. potential target against mycoplasma infections. | mycoplasmas contain glycoglycerolipids in their plasma membrane as key structural components involved in bilayer properties and stability. a membrane-associated glycosyltransferase, gt mg517, has been identified in mycoplasma genitalium, which sequentially produces monoglycosyl- and diglycosyldiacylglycerols (mgdag and dgdag). when recombinantly expressed in e. coli, the enzyme was functional in vivo and yielded membrane glycolipids from which glc+¦1,6glc+¦dag was identified as the main product. ... | 2011 | 21835921 |
| horizontal gene exchange in environmental microbiota. | horizontal gene transfer (hgt) plays an important role in the evolution of life on the earth. this view is supported by numerous occasions of hgt that are recorded in the genomes of all three domains of living organisms. hgt-mediated rapid evolution is especially noticeable among the bacteria, which demonstrate formidable adaptability in the face of recent environmental changes imposed by human activities, such as the use of antibiotics, industrial contamination, and intensive agriculture. at th ... | 2011 | 21845185 |
| the repertoire of ice in prokaryotes underscores the unity, diversity, and ubiquity of conjugation. | horizontal gene transfer shapes the genomes of prokaryotes by allowing rapid acquisition of novel adaptive functions. conjugation allows the broadest range and the highest gene transfer input per transfer event. while conjugative plasmids have been studied for decades, the number and diversity of integrative conjugative elements (ice) in prokaryotes remained unknown. we defined a large set of protein profiles of the conjugation machinery to scan over 1,000 genomes of prokaryotes. we found 682 pu ... | 2011 | 21876676 |
| Is the sequence-specific binding of aminoacyl-tRNAs by EF-Tu universal among bacteria? | Three base pairs in the T-stem are primarily responsible for the sequence-specific interaction of tRNA with Escherichia coli and Thermus thermophilus EF-Tu. While the amino acids on the surface of EF-Tu that contact aminoacyl-tRNA (aa-tRNA) are highly conserved among bacteria, the T-stem sequences of individual tRNA are variable, making it unclear whether or not this protein-nucleic acid interaction is also sequence specific in other bacteria. We propose and validate a thermodynamic model that p ... | 2011 | 21893586 |
| a simple method to evaluate the number of bradyrhizobia on soybean seeds and its implication on inoculant quality control. | abstract: soybean seeds are non-sterile and their bacterial population interferes with the enumeration of beneficial bacteria, making it difficult to assess survival under different conditions. within this context, the principal aims of this work were: (1) to improve a selective media for the enumeration of b. japonicum recovered from inoculated soybean seeds; (2) to establish the most representative mathematical function for b. japonicum mortality on soybean seeds after inoculation; (3) to eval ... | 2011 | 21906377 |
| Lotus japonicus nodulation is photomorphogenetically controlled by sensing the red/far red (R/FR) ratio through jasmonic acid (JA) signaling. | Light is critical for supplying carbon to the energetically expensive, nitrogen-fixing symbiosis between legumes and rhizobia. Here, we show that phytochrome B (phyB) is part of the monitoring system to detect suboptimal light conditions, which normally suppress Lotus japonicus nodule development after Mesorhizobium loti inoculation. We found that the number of nodules produced by L. japonicus phyB mutants is significantly reduced compared with the number produced of WT Miyakojima MG20. To explo ... | 2011 | 21930895 |
| Interplay of flg22-induced defence responses and nodulation in Lotus japonicus. | In this study the interplay between the symbiotic and defence signalling pathways in Lotus japonicus was investigated by comparing the responses to Mesorhizobium loti, the symbiotic partner of L. japonicus, and the elicitor flg22, a conserved peptide motif present in flagellar protein of a wide range of bacteria. It was found that defence and symbiotic pathways overlap in the interaction between L. japonicus and M. loti since similar responses were induced by the mutualistic bacteria and flg22. ... | 2012 | 21934117 |
| Interplay of flg22-induced defence responses and nodulation in Lotus japonicus. | In this study the interplay between the symbiotic and defence signalling pathways in Lotus japonicus was investigated by comparing the responses to Mesorhizobium loti, the symbiotic partner of L. japonicus, and the elicitor flg22, a conserved peptide motif present in flagellar protein of a wide range of bacteria. It was found that defence and symbiotic pathways overlap in the interaction between L. japonicus and M. loti since similar responses were induced by the mutualistic bacteria and flg22. ... | 2012 | 21934117 |
| the evolution of function in strictosidine synthase-like proteins. | the exponential growth of sequence data provides abundant information for the discovery of new enzyme reactions. correctly annotating the functions of highly diverse proteins can be difficult, however, hindering use of this information. global analysis of large superfamilies of related proteins is a powerful strategy for understanding the evolution of reactions by identifying catalytic commonalities and differences in reaction and substrate specificity, even when only a few members have been bio ... | 2011 | 21948213 |
| biological consequences of ancient gene acquisition and duplication in the large genome of candidatus solibacter usitatus ellin6076. | members of the bacterial phylum acidobacteria are widespread in soils and sediments worldwide, and are abundant in many soils. acidobacteria are challenging to culture in vitro, and many basic features of their biology and functional roles in the soil have not been determined. candidatus solibacter usitatus strain ellin6076 has a 9.9 mb genome that is approximately 2-5 times as large as the other sequenced acidobacteria genomes. bacterial genome sizes typically range from 0.5 to 10 mb and are in ... | 2011 | 21949776 |
| Recent Progress in Development of Tnt1 Functional Genomics Platform for Medicago truncatula and Lotus japonicus in Bulgaria. | Legumes, as protein-rich crops, are widely used for human food, animal feed and vegetable oil production. Over the past decade, two legume species, Medicago truncatula and Lotus japonicus, have been adopted as model legumes for genomics and physiological studies. The tobacco transposable element, Tnt1, is a powerful tool for insertional mutagenesis and gene inactivation in plants. A large collection of Tnt1-tagged lines of M. truncatula cv. Jemalong was generated during the course of the project ... | 2011 | 21966253 |
| sequence variability of rhizobiales orthologs and relationship with physico-chemical characteristics of proteins. | chromosomal orthologs can reveal the shared ancestral gene set and their evolutionary trends. additionally, physico-chemical properties of encoded proteins could provide information about functional adaptation and ecological niche requirements. | 2011 | 21970442 |
| nodulin 41, a novel late nodulin of common bean with peptidase activity. | the legume-rhizobium symbiosis requires the formation of root nodules, specialized organs where the nitrogen fixation process takes place. nodule development is accompanied by the induction of specific plant genes, referred to as nodulin genes. important roles in processes such as morphogenesis and metabolism have been assigned to nodulins during the legume-rhizobium symbiosis. | 2011 | 21985276 |
| bacterial transition metal p(1b)-atpases: transport mechanism and roles in virulence. | p(1b)-type atpases are polytopic membrane proteins that couple the hydrolysis of atp to the efflux of cytoplasmic transition metals. this paper reviews recent progress in our understanding of the structure and function of these proteins in bacteria. these are members of the p-type superfamily of transport atpases. cu(+)-atpases are the most frequently observed and best-characterized members of this group of transporters. however, bacterial genomes show diverse arrays of p(1b)-type atpases with a ... | 2011 | 21999638 |
| a novel hydrolase identified by genomic-proteomic analysis of phenylurea herbicide mineralization by variovorax sp. strain srs16. | the soil bacterial isolate variovorax sp. strain srs16 mineralizes the phenylurea herbicide linuron. the proposed pathway initiates with hydrolysis of linuron to 3,4-dichloroaniline (dca) and n,o-dimethylhydroxylamine, followed by conversion of dca to krebs cycle intermediates. differential proteomic analysis showed a linuron-dependent upregulation of several enzymes that fit into this pathway, including an amidase (liba), a multicomponent chloroaniline dioxygenase, and enzymes associated with a ... | 2011 | 22003008 |
| photorespiratory metabolism and nodule function: behavior of lotus japonicus mutants deficient in plastid glutamine synthetase. | two photorespiratory mutants of lotus japonicus deficient in plastid glutamine synthetase (gs(2)) were examined for their capacity to establish symbiotic association with mesorhizobium loti bacteria. biosynthetic glutamine synthetase (gs) activity was reduced by around 40% in crude nodule extracts from mutant plants as compared with the wild type (wt). western blot analysis further confirmed the lack of gs(2) polypeptide in mutant nodules. the decrease in gs activity affected the nodular carbon ... | 2011 | 22007601 |
| quantitative trait locus analysis of symbiotic nitrogen fixation activity in the model legume lotus japonicus. | many legumes form nitrogen-fixing root nodules. an elevation of nitrogen fixation in such legumes would have significant implications for plant growth and biomass production in agriculture. to identify the genetic basis for the regulation of nitrogen fixation, quantitative trait locus (qtl) analysis was conducted with recombinant inbred lines derived from the cross miyakojima mg-20 × gifu b-129 in the model legume lotus japonicus. this population was inoculated with mesorhizobium loti maff303099 ... | 2011 | 22009016 |
| the rhizome of reclinomonas americana, homo sapiens, pediculus humanus and saccharomyces cerevisiae mitochondria. | mitochondria are thought to have evolved from eubacteria-like endosymbionts; however, the origin of the mitochondrion remains a subject of debate. in this study, we investigated the phenomenon of chimerism in mitochondria to shed light on the origin of these organelles by determining which species played a role in their formation. we used the mitochondria of four distinct organisms, reclinomonas americana, homo sapiens, saccharomyces cerevisiae and multichromosome pediculus humanus, and attempte ... | 2011 | 22014084 |
| sequence and role in virulence of the three plasmid complement of the model tumor-inducing bacterium pseudomonas savastanoi pv. savastanoi ncppb 3335. | pseudomonas savastanoi pv. savastanoi ncppb 3335 is a model for the study of the molecular basis of disease production and tumor formation in woody hosts, and its draft genome sequence has been recently obtained. here we closed the sequence of the plasmid complement of this strain, composed of three circular molecules of 78,357 nt (ppsv48a), 45,220 nt (ppsv48b), and 42,103 nt (ppsv48c), all belonging to the ppt23a-like family of plasmids widely distributed in the p. syringae complex. a total of ... | 2011 | 22022435 |
| identification of a eukaryotic reductive dechlorinase and characterization of its mechanism of action on its natural substrate. | chlorinated compounds are important environmental pollutants whose biodegradation may be limited by inefficient dechlorinating enzymes. dictyostelium amoebae produce a chlorinated alkyl phenone called dif which induces stalk cell differentiation during their multicellular development. here we describe the identification of dif dechlorinase. dif dechlorinase is active when expressed in bacteria, and activity is lost from dictyostelium cells when its gene, drca, is knocked out. it has a k(m) for d ... | 2011 | 22035794 |
| excision of an unstable pathogenicity island in salmonella enterica serovar enteritidis is induced during infection of phagocytic cells. | the availability of the complete genome sequence of several salmonella enterica serovars has revealed the presence of unstable genetic elements in these bacteria, such as pathogenicity islands and prophages. this is the case of salmonella enterica serovar enteritidis (s. enteritidis), a bacterium that causes gastroenteritis in humans and systemic infection in mice. the whole genome sequence analysis for s. enteritidis unveiled the presence of several genetic regions that are absent in other salm ... | 2011 | 22039432 |
| expression screening of fusion partners from an e. coli genome for soluble expression of recombinant proteins in a cell-free protein synthesis system. | while access to soluble recombinant proteins is essential for a number of proteome studies, preparation of purified functional proteins is often limited by the protein solubility. in this study, potent solubility-enhancing fusion partners were screened from the repertoire of endogenous e. coli proteins. based on the presumed correlation between the intracellular abundance and folding efficiency of proteins, pcr-amplified orfs of a series of highly abundant e. coli proteins were fused with aggreg ... | 2011 | 22073212 |
| characterization of highly efficient heavy-ion mutagenesis in arabidopsis thaliana. | heavy-ion mutagenesis is recognised as a powerful technology to generate new mutants, especially in higher plants. heavy-ion beams show high linear energy transfer (let) and thus more effectively induce dna double-strand breaks than other mutagenic techniques. previously, we determined the most effective heavy-ion let (letmax: 30.0 kev μm(-1)) for arabidopsis mutagenesis by analysing the effect of let on mutation induction. however, the molecular structure of mutated dna induced by heavy ions wi ... | 2011 | 22085561 |
| contribution of nfp lysm domains to the recognition of nod factors during the medicago truncatula/sinorhizobium meliloti symbiosis. | the root nodule nitrogen fixing symbiosis between legume plants and soil bacteria called rhizobia is of great agronomical and ecological interest since it provides the plant with fixed atmospheric nitrogen. the establishment of this symbiosis is mediated by the recognition by the host plant of lipo-chitooligosaccharides called nod factors (nfs), produced by the rhizobia. this recognition is highly specific, as precise nf structures are required depending on the host plant. here, we study the imp ... | 2011 | 22087221 |
| gating of the mlotik1 potassium channel involves large rearrangements of the cyclic nucleotide-binding domains. | cyclic nucleotide-regulated ion channels are present in bacteria, plants, vertebrates, and humans. in higher organisms, they are closely involved in signaling networks of vision and olfaction. binding of camp or cgmp favors the activation of these ion channels. despite a wealth of structural and studies, there is a lack of structural data describing the gating process in a full-length cyclic nucleotide-regulated channel. we used high-resolution atomic force microscopy (afm) to directly observe t ... | 2011 | 22135457 |
| Identification of a novel gene for biosynthesis of a bacteroid-specific electron carrier menaquinone. | Ubiquinone (UQ) has been considered as an electron mediator in electron transfer that generates ATP in Rhizobium under both free-living and symbiosis conditions. When mutated, the dmtH gene has a symbiotic phenotype of forming ineffective nodules on Astragalus sinicus. The gene was isolated from a Mesorhizobium huakuii 7653R transposon-inserted mutant library. The DNA sequence and conserved protein domain analyses revealed that dmtH encodes demethylmenaquinone (DMK) methyltransferase, which cata ... | 2011 | 22194970 |
| legume pectate lyase required for root infection by rhizobia. | to allow rhizobial infection of legume roots, plant cell walls must be locally degraded for plant-made infection threads (its) to be formed. here we identify a lotus japonicus nodulation pectate lyase gene (ljnpl), which is induced in roots and root hairs by rhizobial nodulation (nod) factors via activation of the nodulation signaling pathway and the nin transcription factor. two ljnpl mutants produced uninfected nodules and most infections arrested as infection foci in root hairs or roots. the ... | 2011 | 22203959 |
| legume pectate lyase required for root infection by rhizobia. | to allow rhizobial infection of legume roots, plant cell walls must be locally degraded for plant-made infection threads (its) to be formed. here we identify a lotus japonicus nodulation pectate lyase gene (ljnpl), which is induced in roots and root hairs by rhizobial nodulation (nod) factors via activation of the nodulation signaling pathway and the nin transcription factor. two ljnpl mutants produced uninfected nodules and most infections arrested as infection foci in root hairs or roots. the ... | 2011 | 22203959 |
| structure of the pilus assembly protein tadz from eubacterium rectale: implications for polar localization. | the tad (tight adherence) locus encodes a protein translocation system that produces a novel variant of type iv pili. the pilus assembly protein tadz (called cpae in caulobacter crescentus) is ubiquitous in tad loci, but is absent in other type iv pilus biogenesis systems. the crystal structure of tadz from eubacterium rectale (ertadz), in complex with atp and mg(2+) , was determined to 2.1 å resolution. ertadz contains an atypical atpase domain with a variant of a deviant walker-a motif that re ... | 2011 | 22211578 |
| crystallization and preliminary x-ray analysis of pyridoxine 4-oxidase, the first enzyme in pyridoxine degradation pathway i. | vitamin b(6)-degradation pathway i has recently been identified in mesorhizobium loti maff303099. pyridoxine 4-oxidase, an fad-dependent enzyme, is the first enzyme in this pathway and catalyzes the irreversible oxidation of pyridoxine to pyridoxal. the enzyme was overexpressed in escherichia coli with a his(6) tag and purified. the recombinant enzyme was crystallized at 277 k by the sitting-drop vapour-diffusion method using peg 4000 as the precipitant. the crystal, which belonged to space grou ... | 2012 | 22232175 |
| crystallization and preliminary x-ray analysis of pyridoxine 4-oxidase, the first enzyme in pyridoxine degradation pathway i. | vitamin b(6)-degradation pathway i has recently been identified in mesorhizobium loti maff303099. pyridoxine 4-oxidase, an fad-dependent enzyme, is the first enzyme in this pathway and catalyzes the irreversible oxidation of pyridoxine to pyridoxal. the enzyme was overexpressed in escherichia coli with a his(6) tag and purified. the recombinant enzyme was crystallized at 277 k by the sitting-drop vapour-diffusion method using peg 4000 as the precipitant. the crystal, which belonged to space grou ... | 2012 | 22232175 |
| tertiary alcohol preferred: hydroxylation of trans-3-methyl-l-proline with proline hydroxylases. | the enzymatic synthesis of tertiary alcohols by the stereospecific oxidation of tertiary alkyl centers is a most-straightforward but challenging approach, since these positions are sterically hindered. in contrast to p450-monooxygenases, there is little known about the potential of non-heme iron(ii) oxygenases to catalyze such reactions. we have studied the hydroxylation of trans-3-methyl-l-proline with the α-ketoglutarate (α-kg) dependent oxygenases, cis-3-proline hydroxylase type ii and cis-4- ... | 2011 | 22238542 |
| wide variation in antibiotic resistance proteins identified by functional metagenomic screening of a soil dna library. | most genes for antibiotic resistance present in soil microbes remain unexplored because most environmental microbes cannot be cultured. only recently has the identification of these genes become feasible through the use of culture-independent methods. we screened a soil metagenomic dna library in an escherichia coli host for genes that can confer resistance to kanamycin, gentamicin, rifampin, trimethoprim, chloramphenicol, or tetracycline. the screen revealed 41 genes that encode novel protein v ... | 2012 | 22247132 |
| draft genome sequence of plant growth-promoting rhizobium mesorhizobium amorphae, isolated from zinc-lead mine tailings. | here, we describe the draft genome sequence of mesorhizobium amorphae strain ccnwgs0123, isolated from nodules of robinia pseudoacacia growing on zinc-lead mine tailings. a large number of metal(loid) resistance genes, as well as genes reported to promote plant growth, were identified, presenting a great future potential for aiding phytoremediation in metal(loid)-contaminated soil. | 2012 | 22247533 |
| rhizobial and fungal symbioses show different requirements for calmodulin binding to calcium calmodulin-dependent protein kinase in lotus japonicus. | ca(2+)/calmodulin (cam)-dependent protein kinase (ccamk) is a key regulator of root nodule and arbuscular mycorrhizal symbioses and is believed to be a decoder for ca(2+) signals induced by microbial symbionts. however, it is unclear how ccamk is activated by these microbes. here, we investigated in vivo activation of ccamk in symbiotic signaling, focusing mainly on the significance of and epistatic relationships among functional domains of ccamk. loss-of-function mutations in ef-hand motifs rev ... | 2012 | 22253228 |
| the mll6786 gene encodes a repressor protein controlling the degradation pathway for vitamin b6 in mesorhizobium loti. | pyridoxine is converted to succinic semialdehyde, acetate, ammonia and co(2) through the actions of eight enzymes. the genes encoding the enzymes occur as a cluster on the chromosomal dna of mesorhizobium loti, a symbiotic nitrogen-fixing bacterium. here, it was found that disruption of the mll6786 gene, which is located between the genes encoding the first and eighth enzymes of the pathway, caused constitutive expression of the eight enzymes. the protein encoded by the mll6786 gene is a member ... | 2012 | 22276911 |
| functional domain analysis of the remorin protein ljsymrem1 in lotus japonicus. | in legumes rhizobial infection during root nodule symbiosis (rns) is controlled by a conserved set of receptor proteins and downstream components. mtsymrem1, a protein of the remorin family in medicago truncatula, was shown to interact with at least three receptor-like kinases (rlks) that are essential for rns. remorins are comprised of a conserved c-terminal domain and a variable n-terminal region that defines the six different remorin groups. while both n- and c-terminal regions of remorins be ... | 2012 | 22292047 |
| transaminases for the synthesis of enantiopure beta-amino acids. | optically pure β-amino acids constitute interesting building blocks for peptidomimetics and a great variety of pharmaceutically important compounds. their efficient synthesis still poses a major challenge. transaminases (also known as aminotransferases) possess a great potential for the synthesis of optically pure β-amino acids. these pyridoxal 5'-dependent enzymes catalyze the transfer of an amino group from a donor substrate to an acceptor, thus enabling the synthesis of a wide variety of chir ... | 2012 | 22293122 |
| salicylic acids: local, systemic or inter-systemic regulators? | salicylic acid is well known phytohormone, emerging recently as a new paradigm of an array of manifestations of growth regulators. the area unleashed yet encompassed the applied agriculture sector to find the roles to strengthen the crops against plethora of abiotic and biotic stresses. the skipped part of integrated picture, however, was the evolutionary insight of salicylic acid to either allow or discard the microbial invasion depending upon various internal factors of two interactants under ... | 2012 | 22301975 |
| nad(p)+-malic enzyme mutants of sinorhizobium sp. strain ngr234, but not azorhizobium caulinodans ors571, maintain symbiotic n2 fixation capabilities. | c(4)-dicarboxylic acids appear to be metabolized via the tricarboxylic acid (tca) cycle in n(2)-fixing bacteria (bacteroids) within legume nodules. in sinorhizobium meliloti bacteroids from alfalfa, nad(+)-malic enzyme (dme) is required for n(2) fixation, and this activity is thought to be required for the anaplerotic synthesis of pyruvate. in contrast, in the pea symbiont rhizobium leguminosarum, pyruvate synthesis occurs via either dme or a pathway catalyzed by phosphoenolpyruvate carboxykinas ... | 2012 | 22307295 |
| draft genome sequence of mesorhizobium alhagi ccnwxj12-2t, a novel salt-resistant species isolated from the desert of northwestern china. | mesorhizobium alhagi strain ccnwxj12-2(t) is a novel species of soil-dwelling, nitrogen-fixing bacteria that can form symbiotic root nodules with alhagi sparsifolia. moreover, the strain has high resistance to salt and alkali. here we report the draft genome sequence of mesorhizobium alhagi strain ccnwxj12-2(t). a large number of osmotic regulation-related genes have been identified. | 2012 | 22328758 |
| nuclear-localized and deregulated calcium- and calmodulin-dependent protein kinase activates rhizobial and mycorrhizal responses in lotus japonicus. | the common symbiosis pathway is at the core of symbiosis signaling between plants and soil microbes. in this pathway, calcium- and calmodulin-dependent protein kinase (ccamk) plays a crucial role in integrating the signals both in arbuscular mycorrhizal symbiosis (ams) and in root nodule symbiosis (rns). however, the molecular mechanism by which ccamk coordinates ams and rns is largely unknown. here, we report that the gain-of-function (gof) variants of ccamk without the regulatory domains activ ... | 2012 | 22337918 |
| metabolomics of forage plants: a review. | forage plant breeding is under increasing pressure to deliver new cultivars with improved yield, quality and persistence to the pastoral industry. new innovations in dna sequencing technologies mean that quantitative trait loci analysis and marker-assisted selection approaches are becoming faster and cheaper, and are increasingly used in the breeding process with the aim to speed it up and improve its precision. high-throughput phenotyping is currently a major bottle neck and emerging technologi ... | 2012 | 22351485 |
| a map kinase kinase interacts with symrk and regulates nodule organogenesis in lotus japonicus. | the symbiosis receptor kinase, symrk, is required for root nodule development. a symrk-interacting protein (sip2) was found to form protein complex with symrk in vitro and in planta. the interaction between symrk and sip2 is conserved in legumes. the sip2 gene was expressed in all lotus japonicus tissues examined. sip2 represents a typical plant mitogen-activated protein kinase kinase (mapkk) and exhibited autophosphorylation and transphosphorylation activities. recombinant sip2 protein could ph ... | 2012 | 22353370 |
| the genome sequence of polymorphum gilvum sl003b-26a1(t) reveals its genetic basis for crude oil degradation and adaptation to the saline soil. | polymorphum gilvum sl003b-26a1(t) is the type strain of a novel species in the recently published novel genus polymorphum isolated from saline soil contaminated with crude oil. it is capable of using crude oil as the sole carbon and energy source and can adapt to saline soil at a temperature of 45°c. the polymorphum gilvum genome provides a genetic basis for understanding how the strain could degrade crude oil and adapt to a saline environment. genome analysis revealed the versatility of the str ... | 2012 | 22359583 |
| a survey of srna families in α-proteobacteria. | we have performed a computational comparative analysis of six small non-coding rna (srna) families in α-proteobacteria. members of these families were first identified in the intergenic regions of the nitrogen-fixing endosymbiont s. meliloti by a combined bioinformatics screen followed by experimental verification. consensus secondary structures inferred from covariance models for each srna family evidenced in some cases conserved motifs putatively relevant to the function of trans-encoded base- ... | 2012 | 22418845 |
| dual effect of mesorhizobium loti t3ss functionality on the symbiotic process. | mesorhizobium loti maff303099 has a functional type iii secretory system (t3ss) involved in the nodulation process on lotus tenuis and lotus japonicus. four putative m. loti t3ss effectors (mlr6358, mlr6331, mlr6361, and mlr6316) have been previously described, and it has been demonstrated that the n-terminal regions of mlr6361 and mlr6358 mediate the secretion via a t3ss. here, we demonstrate the capacity of mlr6316 and mlr6331 n-terminal regions to direct the secretion of a translational fusio ... | 2012 | 22428564 |
| the small gtpase rop6 interacts with nfr5 and is involved in nodule formation in lotus japonicus. | nod factor receptor5 (nfr5) is an atypical receptor-like kinase, having no activation loop in the protein kinase domain. it forms a heterodimer with nfr1 and is required for the early plant responses to rhizobium infection. a rho-like small gtpase from lotus japonicus was identified as an nfr5-interacting protein. the amino acid sequence of this rho-like gtpase is closest to the arabidopsis (arabidopsis thaliana) rop6 and medicago truncatula rop6 and was designated as ljrop6. the interaction bet ... | 2012 | 22434040 |
| thiol synthetases of legumes: immunogold localization and differential gene regulation by phytohormones. | in plants and other organisms, glutathione (gsh) biosynthesis is catalysed sequentially by γ-glutamylcysteine synthetase (γecs) and glutathione synthetase (gshs). in legumes, homoglutathione (hgsh) can replace gsh and is synthesized by γecs and a specific homoglutathione synthetase (hgshs). the subcellular localization of the enzymes was examined by electron microscopy in several legumes and gene expression was analysed in lotus japonicus plants treated for 1-48 h with 50 μm of hormones. immunog ... | 2012 | 22442424 |
| complete genome sequence of bradyrhizobium sp. s23321: insights into symbiosis evolution in soil oligotrophs. | bradyrhizobium sp. s23321 is an oligotrophic bacterium isolated from paddy field soil. although s23321 is phylogenetically close to bradyrhizobium japonicum usda110, a legume symbiont, it is unable to induce root nodules in siratro, a legume often used for testing nod factor-dependent nodulation. the genome of s23321 is a single circular chromosome, 7,231,841 bp in length, with an average gc content of 64.3%. the genome contains 6,898 potential protein-encoding genes, one set of rrna genes, and ... | 2012 | 22452844 |
| molecular characterization of the lotus japonicus nrt1(ptr) and nrt2 families. | nitrate is an essential element for plant growth, both as a primary nutrient in the nitrogen assimilation pathway and as an important signal for plant development. low- and high-affinity transport systems are involved in the nitrate uptake from the soil and its distribution between different plant tissues. by an in silico search, we identified putative members of both systems in the model legume lotus japonicus. we investigated, by a time course analysis, the transcripts abundance in root tissue ... | 2012 | 22458810 |
| non-symbiotic haemoglobins-what's happening beyond nitric oxide scavenging? | non-symbiotic haemoglobins have been an active research topic for over 30 years, during which time a considerable portfolio of knowledge has accumulated relative to their chemical and molecular properties, and their presence and mode of induction in plants. while progress has been made towards understanding their physiological role, there remain a number of unanswered questions with respect to their biological function. this review attempts to update recent progress in this area and to introduce ... | 2012 | 22479675 |
| a positive correlation between bacterial autoaggregation and biofilm formation in native sinorhizobium meliloti isolates from argentina. | sinorhizobium meliloti is a symbiotic nitrogen-fixing bacterium that elicits nodule formation on roots of alfalfa plants. s. meliloti produces two exopolysaccharides (epss), termed eps i and eps ii, that are both able to promote symbiosis. eps i and eps ii are secreted in two major fractions that reflect differing degrees of subunit polymerization, designated high- and low-molecular-weight fractions. we reported previously that epss are crucial for autoaggregation and biofilm formation in s. mel ... | 2012 | 22492433 |
| conservation of gene order and content in the circular chromosomes of 'candidatus liberibacter asiaticus' and other rhizobiales. | 'ca. liberibacter asiaticus,' an insect-vectored, obligate intracellular bacterium associated with citrus-greening disease, also called "hlb," is a member of the rhizobiales along with nitrogen-fixing microsymbionts sinorhizobium meliloti and bradyrhizobium japonicum, plant pathogen agrobacterium tumefaciens and facultative intracellular mammalian pathogen bartonella henselae. comparative analyses of their circular chromosomes identified 514 orthologous genes shared among all five species. share ... | 2012 | 22496839 |
| towards a more accurate annotation of tyrosine-based site-specific recombinases in bacterial genomes. | tyrosine-based site-specific recombinases (tbssrs) are dna breaking-rejoining enzymes. in bacterial genomes, they play a major role in the comings and goings of mobile genetic elements (mges), such as temperate phage genomes, integrated conjugative elements (ices) or integron cassettes. tbssrs are also involved in the segregation of plasmids and chromosomes, the resolution of plasmid dimers and of co-integrates resulting from the replicative transposition of transposons. with the aim of improvin ... | 2012 | 22502997 |
| lotus japonicus e3 ligase seven in absentia4 destabilizes the symbiosis receptor-like kinase symrk and negatively regulates rhizobial infection. | the lotus japonicus symbiosis receptor-like kinase (symrk) is required for symbiotic signal transduction upon stimulation of root cells by microbial signaling molecules. here, we identified members of the seven in absentia (sina) e3 ubiquitin-ligase family as symrk interactors and confirmed their predicted ubiquitin-ligase activity. in nicotiana benthamiana leaves, symrk-yellow fluorescent protein was localized at the plasma membrane, and interaction with sinas, as determined by bimolecular fluo ... | 2012 | 22534128 |
| structural basis of a protein partner switch that regulates the general stress response of α-proteobacteria. | α-proteobacteria uniquely integrate features of two-component signal transduction (tcs) and alternative sigma factor (σ) regulation to control transcription in response to general stress. the core of this regulatory system is the phyr protein, which contains a σ-like (sl) domain and a tcs receiver domain. aspartyl phosphorylation of the phyr receiver in response to stress signals promotes binding of the anti-σ factor, nepr, to phyr-sl. this mechanism, whereby nepr switches binding between its co ... | 2012 | 22550172 |
| ss-sl2, a novel cell wall protein with pan modules, is essential for sclerotial development and cellular integrity of sclerotinia sclerotiorum. | the sclerotium is an important dormant body for many plant fungal pathogens. here, we reported that a protein, named ss-sl2, is involved in sclerotial development of sclerotinia sclerotiorum. ss-sl2 does not show significant homology with any protein of known function. ss-sl2 contains two putative pan modules which were found in other proteins with diverse adhesion functions. ss-sl2 is a secreted protein, during the initial stage of sclerotial development, copious amounts of ss-sl2 are secreted ... | 2012 | 22558105 |
| shade avoidance. | the presence of neighboring vegetation modifies the light environment experienced by plants, generating signals that are perceived by phytochromes and cryptochromes. these signals cause large changes in plant body form and function, including enhanced growth of the hypocotyl and petioles, a more erect position of the leaves and early flowering in arabidopsis thaliana. collectively, these so-called shade-avoidance responses tend to reduce the degree of current or future shade by neighbors. shade ... | 2012 | 22582029 |
| a comparative genomics screen identifies a sinorhizobium meliloti 1021 sodm-like gene strongly expressed within host plant nodules. | we have used the genomic data in the integrated microbial genomes system of the department of energy's joint genome institute to make predictions about rhizobial open reading frames that play a role in nodulation of host plants. the genomic data was screened by searching for orfs conserved in α-proteobacterial rhizobia, but not conserved in closely-related non-nitrogen-fixing α-proteobacteria. | 2012 | 22587634 |
| allosteric mutants show that prfa activation is dispensable for vacuole escape but required for efficient spread and listeria survival in vivo. | the transcriptional regulator prfa controls key virulence determinants of the facultative intracellular pathogen listeria monocytogenes. prfa-dependent gene expression is strongly induced within host cells. while the basis of this activation is unknown, the structural homology of prfa with the camp receptor protein (crp) and the finding of constitutively activated prfa* mutants suggests it may involve ligand-induced allostery. here, we report the identification of a solvent-accessible cavity wit ... | 2012 | 22646689 |