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Sample records for rhizobia nodulating lotus

  1. Identification of Lotus rhizobia by direct DNA hybridization of crushed root nodules

    SciTech Connect

    Cooper, J.E.; Bjourson, A.J.; Thompson, J.K.

    1987-07-01

    Hybridization of crushed Lotus pedunculatus root nodules with /sup 32/P-labeled total genomic DNA probes was used to identify Rhizobium loti and Bradyrhizobium sp. (Lotus rhizobia). Probes always hybridized with homologous target DNA and frequency with DNAs of other strains from the same genus. Intergeneric hybridization did not occur. Results were comparable to those from colony hybridization.

  2. The Temperature-Sensitive brush Mutant of the Legume Lotus japonicus Reveals a Link between Root Development and Nodule Infection by Rhizobia[C][W][OA

    PubMed Central

    Maekawa-Yoshikawa, Makoto; Müller, Judith; Takeda, Naoya; Maekawa, Takaki; Sato, Shusei; Tabata, Satoshi; Perry, Jillian; Wang, Trevor L.; Groth, Martin; Brachmann, Andreas; Parniske, Martin

    2009-01-01

    The brush mutant of Lotus japonicus exhibits a temperature-dependent impairment in nodule, root, and shoot development. At 26°C, brush formed fewer nodules, most of which were not colonized by rhizobia bacteria. Primary root growth was retarded and the anatomy of the brush root apical meristem revealed distorted cellular organization and reduced cell expansion. Reciprocal grafting of brush with wild-type plants indicated that this genotype only affected the root and that the shoot phenotype was a secondary effect. The root and nodulation phenotype cosegregated as a single Mendelian trait and the BRUSH gene could be mapped to the short arm of chromosome 2. At 18°C, the brush root anatomy was rescued and similar to the wild type, and primary root length, number of infection threads, and nodule formation were partially rescued. Superficially, the brush root phenotype resembled the ethylene-related thick short root syndrome. However, treatment with ethylene inhibitor did not recover the observed phenotypes, although brush primary roots were slightly longer. The defects of brush in root architecture and infection thread development, together with intact nodule architecture and complete absence of symptoms from shoots, suggest that BRUSH affects cellular differentiation in a tissue-dependent way. PMID:19176723

  3. Genetic Diversity and Host Range of Rhizobia Nodulating Lotus tenuis in Typical Soils of the Salado River Basin (Argentina)▿ †

    PubMed Central

    Estrella, María Julia; Muñoz, Socorro; Soto, María José; Ruiz, Oscar; Sanjuán, Juan

    2009-01-01

    A total of 103 root nodule isolates were used to estimate the diversity of bacteria nodulating Lotus tenuis in typical soils of the Salado River Basin. A high level of genetic diversity was revealed by repetitive extragenic palindromic PCR, and 77 isolates with unique genomic fingerprints were further differentiated into two clusters, clusters A and B, after 16S rRNA restriction fragment length polymorphism analysis. Cluster A strains appeared to be related to the genus Mesorhizobium, whereas cluster B was related to the genus Rhizobium. 16S rRNA sequence and phylogenetic analysis further supported the distribution of most of the symbiotic isolates in either Rhizobium or Mesorhizobium: the only exception was isolate BA135, whose 16S rRNA gene was closely related to the 16S rRNA gene of the genus Aminobacter. Most Mesorhizobium-like isolates were closely related to Mesorhizobium amorphae, Mesorhizobium mediterraneum, Mesorhizobium tianshanense, or the broad-host-range strain NZP2037, but surprisingly few isolates grouped with Mesorhizobium loti type strain NZP2213. Rhizobium-like strains were related to Rhizobium gallicum, Rhizobium etli, or Rhizobium tropici, for which Phaseolus vulgaris is a common host. However, no nodC or nifH genes could be amplified from the L. tenuis isolates, suggesting that they have rather divergent symbiosis genes. In contrast, nodC genes from the Mesorhizobium and Aminobacter strains were closely related to nodC genes from narrow-host-range M. loti strains. Likewise, nifH gene sequences were very highly conserved among the Argentinian isolates and reference Lotus rhizobia. The high levels of conservation of the nodC and nifH genes suggest that there was a common origin of the symbiosis genes in narrow-host-range Lotus symbionts, supporting the hypothesis that both intrageneric horizontal gene transfer and intergeneric horizontal gene transfer are important mechanisms for the spread of symbiotic capacity in the Salado River Basin. PMID

  4. Nodulation genes and type III secretion systems in rhizobia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For establishment of symbiosis, rhizobia and legumes have to communicate. Specific signaling starts with the release of flavonoids by the plant. All rhizobia encode at least one NodD protein, which responds to the presence of specific flavonoids by activation of nodulation genes. In Bradyrhizobium j...

  5. Four unnamed species of nonsymbiotic rhizobia isolated from the rhizosphere of Lotus corniculatus.

    PubMed Central

    Sullivan, J T; Eardly, B D; van Berkum, P; Ronson, C W

    1996-01-01

    Previously, we found that genetically diverse rhizobia nodulating Lotus corniculatus at a field site devoid of naturalized rhizobia had symbiotic DNA regions identical to those of ICMP3153, the inoculant strain used at the site (J. T. Sullivan, H. N. Patrick, W. L. Lowther, D. B. Scott, and C. W. Ronson, Proc. Natl. Acad. Sci. USA 92:8985-8989, 1995). In this study, we characterized seven nonsymbiotic rhizobial isolates from the rhizosphere of L. corniculatus. These included two from plants at the field site sampled by Sullivan et al. and five from plants at a new field plot adjacent to that site. The isolates did not nodulate Lotus species or hybridize to symbiotic gene probes but did hybridize to genomic DNA probes from Rhizobium loti. Their genetic relationships with symbiotic isolates obtained from the same sites, with inoculant strain ICMP3153, and with R. loti NZP2213T were determined by three methods. Genetic distance estimates based on genomic DNA-DNA hybridization and multilocus enzyme electrophoresis were correlated but were not consistently reflected by 16S rRNA nucleotide sequence divergence. The nonsymbiotic isolates represented four genomic species that were related to R. loti; the diverse symbiotic isolates from the site belonged to one of these species. The inoculant strain ICMP3153 belonged to a fifth genomic species that was more closely related to Rhizobium huakuii. These results support the proposal that nonsymbiotic rhizobia persist in soils in the absence of legumes and acquire symbiotic genes from inoculant strains upon introduction of host legumes. PMID:8702274

  6. Nodulation outer proteins: double-edged swords of symbiotic rhizobia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizobia are nitrogen-fixing bacteria that establish a nodule symbiosis with legumes. Nodule formation is the result of a complex bacterial infection process, which depends on signals and surface determinants produced by both symbiotic partners. Among them, rhizobial nodulation outer proteins (Nops)...

  7. A Dicarboxylate Transporter, LjALMT4, Mainly Expressed in Nodules of Lotus japonicus.

    PubMed

    Takanashi, Kojiro; Sasaki, Takayuki; Kan, Tomohiro; Saida, Yuka; Sugiyama, Akifumi; Yamamoto, Yoko; Yazaki, Kazufumi

    2016-07-01

    Legume plants can establish symbiosis with soil bacteria called rhizobia to obtain nitrogen as a nutrient directly from atmospheric N2 via symbiotic nitrogen fixation. Legumes and rhizobia form nodules, symbiotic organs in which fixed-nitrogen and photosynthetic products are exchanged between rhizobia and plant cells. The photosynthetic products supplied to rhizobia are thought to be dicarboxylates but little is known about the movement of dicarboxylates in the nodules. In terms of dicarboxylate transporters, an aluminum-activated malate transporter (ALMT) family is a strong candidate responsible for the membrane transport of carboxylates in nodules. Among the seven ALMT genes in the Lotus japonicus genome, only one, LjALMT4, shows a high expression in the nodules. LjALMT4 showed transport activity in a Xenopus oocyte system, with LjALMT4 mediating the efflux of dicarboxylates including malate, succinate, and fumarate, but not tricarboxylates such as citrate. LjALMT4 also mediated the influx of several inorganic anions. Organ-specific gene expression analysis showed LjALMT4 mRNA mainly in the parenchyma cells of nodule vascular bundles. These results suggest that LjALMT4 may not be involved in the direct supply of dicarboxylates to rhizobia in infected cells but is responsible for supplying malate as well as several anions necessary for symbiotic nitrogen fixation, via nodule vasculatures. PMID:27183039

  8. Lotus endemic to the Canary Islands are nodulated by diverse and novel rhizobial species and symbiotypes.

    PubMed

    Lorite, Ma José; Donate-Correa, Javier; del Arco-Aguilar, Marcelino; Pérez Galdona, Ricardo; Sanjuán, Juan; León-Barrios, Milagros

    2010-08-01

    Genetic and symbiotic characterization of 34 isolates from several Lotus species endemic to the Canary Islands showed extraordinary diversity, with bacteria belonging to different species of the genera Mesorhizobium (17 isolates), Sinorhizobium (12 isolates) and Rhizobium/Agrobacterium (5 isolates). In a previous report, we showed that the Sinorhizobium isolates mostly belonged to S. meliloti. Here, we focused on the remaining isolates. The Lotus mesorhizobial strains were distributed in the rrs tree within six poorly resolved branches. Partial sequences from atpD and recA genes produced much better resolved phylogenies that were, with some exceptions, congruent with the ribosomal phylogeny. Thus, up to six different mesorhizobial species were detected, which matched with or were sister species of M. ciceri, M. alhagi, M. plurifarium or M. caraganae, and two represented new lineages that did not correspond to any of the currently recognized species. Neither M. loti nor Bradyrhizobium sp. (Lotus), recognized as the typical Lotus-symbionts, were identified among the Canarian Lotus isolates, although their nodulation genes were closely related to M. loti. However, several subbranches of mesorhizobia nodulating Lotus spp. could be differentiated in a nodC tree, with the isolates from the islands distributed in two of them (A1 and A3). Subbranch A1 included reference strains of M. loti and a group of isolates with a host range compatible with biovar loti, whereas A3 represented a more divergent exclusive subbranch of isolates with a host range almost restricted to endemic Lotus and it could represent a new biovar among the Lotus rhizobia. PMID:20447791

  9. Involvement of auxin distribution in root nodule development of Lotus japonicus.

    PubMed

    Takanashi, Kojiro; Sugiyama, Akifumi; Yazaki, Kazufumi

    2011-07-01

    The symbiosis between legume plants and rhizobia causes the development of new organs, nodules which function as an apparatus for nitrogen fixation. In this study, the roles of auxin in nodule development in Lotus japonicus have been demonstrated using molecular genetic tools and auxin inhibitors. The expression of an auxin-reporter GH3 fused to β-glucuronidase (GUS) was analyzed in L. japonicus roots, and showed a strong signal in the central cylinder of the root, whereas upon rhizobium infection, generation of GUS signal was observed at the dividing outer cortical cells during the first nodule cell divisions. When nodules were developed to maturity, strong GUS staining was detected in vascular tissues of nodules, suggesting distinct auxin involvement in the determinate nodule development. Numbers and the development of nodules were affected by auxin transport inhibitors (1-naphthylphthalamic acid, NPA and triindobenzoic acid, TIBA), and by a newly synthesized auxin antagonist, α-(phenyl ethyl-2-one)-indole-3-acetic acid (PEO-IAA). The common phenotypical alteration by these auxin inhibitors was the inhibition in forming lenticel which is normally developed on the nodule surface from the root outer cortex. The inhibition of lenticel formation was correlated with the inhibition of nodule vascular bundle development. These results indicate that auxin is required for the normal development of determinate nodules in a multidirectional manner. PMID:21369920

  10. Enzymes of the Glyoxylate Cycle in Rhizobia and Nodules of Legumes 1

    PubMed Central

    Johnson, Gordon V.; Evans, Harold J.; Ching, Temay

    1966-01-01

    The relatively high level of fatty acids in soybean nodules and rhizobia from soybean nodules suggested that the glyoxylate cycle might have a role in nodule metabolism. Several species of rhizobia in pure culture were found to have malate synthetase activity when grown on a number of different carbon sources. Significant isocitrate lyase activity was induced when oleate, which presumably may act as an acetyl CoA precursor, was utilized as the principle carbon source. Malate synthetase was active in extracts of rhizobia from nodules of bush bean (Phaseolus vulgaris L.), cowpea (Vigna sinensis L.), lupine (Lupinus angustifolius L.) and soybean (Glycine max L. Merr.). Activity of malate synthetase was, however, barely detectable in rhizobia from alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.) and pea (Pisum sativum L.) nodules. Appreciable isocitrate lyase activity was not detected in rhizobia from nodules nor was it induced by depletion of endogenous substrates by incubation of excised bush bean nodules. Although rhizobia has the potential for the formation of the key enzymes of the glyoxylate cycle, the absence of isocitrate lyase activity in bacteria isolated from nodules indicated that the glyoxylate cycle does not operate in the symbiotic growth of rhizobia and that the observed high content of fatty acids in nodules and nodule bacteria probably is related to a structural role. PMID:16656404

  11. Genetic diversity of rhizobia nodulating native Vicia spp. in Sweden.

    PubMed

    Ampomah, Osei Yaw; Huss-Danell, Kerstin

    2016-05-01

    Despite the recognition that Rhizobium leguminosarum sv. viciae is the most common symbiont of Vicia species worldwide, there is no available information on rhizobia nodulating native Vicia species in Sweden. We have therefore studied the genetic diversity and phylogeny of root nodule bacteria isolated from V. cracca, V. hirsuta, V. sepium, V. tetrasperma and V. sylvatica growing in different locations in Sweden as well as an isolate each from V. cracca in Tromsø, Norway, and V. multicaulis in Siberia, Russia. Out of 25 isolates sampled from the six Vicia species in 12 different locations, there were 14 different genotypes based on the atpD, recA and nodA gene phylogenies. All isolates were classified into Rhizobium leguminosarum sv. viciae group based on the concatenated atpD and recA phylogeny and the nodA phylogeny. PMID:26924220

  12. Cessation of photosynthesis in Lotus japonicus leaves leads to reprogramming of nodule metabolism

    PubMed Central

    Flemetakis, Emmanouil

    2013-01-01

    Symbiotic nitrogen fixation (SNF) involves global changes in gene expression and metabolite accumulation in both rhizobia and the host plant. In order to study the metabolic changes mediated by leaf–root interaction, photosynthesis was limited in leaves by exposure of plants to darkness, and subsequently gene expression was profiled by real-time reverse transcription–PCR (RT–PCR) and metabolite levels by gas chromatography–mass spectrometry in the nodules of the model legume Lotus japonicus. Photosynthetic carbon deficiency caused by prolonged darkness affected many metabolic processes in L. japonicus nodules. Most of the metabolic genes analysed were down-regulated during the extended dark period. In addition to that, the levels of most metabolites decreased or remained unaltered, although accumulation of amino acids was observed. Reduced glycolysis and carbon fixation resulted in lower organic acid levels, especially of malate, the primary source of carbon for bacteroid metabolism and SNF. The high amino acid concentrations together with a reduction in total protein concentration indicate possible protein degradation in nodules under these conditions. Interestingly, comparisons between amino acid and protein content in various organs indicated systemic changes in response to prolonged darkness between nodulated and non-nodulated plants, rendering the nodule a source organ for both C and N under these conditions. PMID:23404899

  13. Cropping history affects nodulation and symbiotic efficiency of distinct hairy vetch genotypes with resident soil rhizobia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Presence of compatible rhizobia strains is essential for nodulation and BNF of hairy vetch (Vicia villosa, HV). We evaluated how past HV cultivation affects nodulation and nitrogen fixation across host genotypes. Five groups of HV genotypes were inoculated with soil dilutions from six paired fields,...

  14. Expression of the CLE-RS3 gene suppresses root nodulation in Lotus japonicus.

    PubMed

    Nishida, Hanna; Handa, Yoshihiro; Tanaka, Sachiko; Suzaki, Takuya; Kawaguchi, Masayoshi

    2016-09-01

    Cell-to-cell communication, principally mediated by short- or long-range mobile signals, is involved in many plant developmental processes. In root nodule symbiosis, a mutual relationship between leguminous plants and nitrogen-fixing rhizobia, the mechanism for the autoregulation of nodulation (AON) plays a key role in preventing the production of an excess number of nodules. AON is based on long-distance cell-to-cell communication between roots and shoots. In Lotus japonicus, two CLAVATA3/ESR-related (CLE) peptides, encoded by CLE-ROOT SIGNAL 1 (CLE-RS1) and -RS2, act as putative root-derived signals that transmit signals inhibiting further nodule development through interaction with a shoot-acting receptor-like kinase HYPERNODULATION ABERRANT ROOT FORMATION 1 (HAR1). Here, an in silico search and subsequent expression analyses enabled us to identify two new L. japonicus CLE genes that are potentially involved in nodulation, designated as CLE-RS3 and LjCLE40. Time-course expression patterns showed that CLE-RS1/2/3 and LjCLE40 expression is induced during nodulation with different activation patterns. Furthermore, constitutive expression of CLE-RS3 significantly suppressed nodule formation in a HAR1-dependent manner. TOO MUCH LOVE, a root-acting regulator of AON, is also required for the CLE-RS3 action. These results suggest that CLE-RS3 is a new component of AON in L. japonicus that may act as a potential root-derived signal through interaction with HAR1. Because CLE-RS2, CLE-RS3 and LjCLE40 are located in tandem in the genome and their expression is induced not only by rhizobial infection but also by nitrate, these genes may have duplicated from a common gene. PMID:27294965

  15. The genetic and biochemical basis for nodulation of legumes by rhizobia

    SciTech Connect

    Pueppke, S.G.

    1996-05-01

    Soil bacteria of the genera Azorhizobium, Bradyrhizobium, and Rhizobium are collectively termed rhizobia. They share the ability to penetrate legume roots and elicit morphological responses that lead to the appearance of nodules. Bacteria within these symbiotic structures fix atmosphere nitrogen and thus are of immense ecological and agricultural significance. Although modern genetic analysis of rhizobia began less than 20 years ago, dozens of nodulation genes have now been identified, some in multiple species of rhizobia. These genetic advances have led to the discovery of a host surveillance system encoded by nodD and to the identification of Nod factor signals. These derivatives of oligochitin are synthesized by the protein products of nodABC, nodFE, NodPQ, and other nodulation genes: they provoke symbiotic responses on the part of the host and have generated immense interest in recent years. The symbiotic functions of other nodulation genes are nonetheless uncertain, and there remain significant gaps in the knowledge of several large groups of rhizobia with interesting biological properties. This review focuses on the nodulation genes of rhizobia, with particular emphasis on the concept of biological specificity of symbiosis with legume host plants. 419 refs.

  16. Down-regulated Lotus japonicus GCR1 plants exhibit nodulation signalling pathways alteration.

    PubMed

    Rogato, Alessandra; Valkov, Vladimir Totev; Alves, Ludovico Martins; Apone, Fabio; Colucci, Gabriella; Chiurazzi, Maurizio

    2016-06-01

    G Protein Coupled Receptor (GPCRs) are integral membrane proteins involved in various signalling pathways by perceiving many extracellular signals and transducing them to heterotrimeric G proteins, which further transduce these signals to intracellular downstream effectors. GCR1 is the only reliable plant candidate as a member of the GPCRs superfamily. In the legume/rhizobia symbiotic interaction, G proteins are involved in signalling pathways controlling different steps of the nodulation program. In order to investigate the putative hierarchic role played by GCR1 in these symbiotic pathways we identified and characterized the Lotus japonicus gene encoding the seven transmembrane GCR1 protein. The detailed molecular and topological analyses of LjGCR1 expression patterns that are presented suggest a possible involvement in the early steps of nodule organogenesis. Furthermore, phenotypic analyses of independent transgenic RNAi lines, showing a significant LjGCR1 expression down regulation, suggest an epistatic action in the control of molecular markers of nodulation pathways, although no macroscopic symbiotic phenotypes could be revealed. PMID:27095401

  17. Proteome Analysis. Novel Proteins Identified at the Peribacteroid Membrane from Lotus japonicus Root Nodules1

    PubMed Central

    Wienkoop, Stefanie; Saalbach, Gerhard

    2003-01-01

    The peribacteroid membrane (PBM) forms the structural and functional interface between the legume plant and the rhizobia. The model legume Lotus japonicus was chosen to study the proteins present at the PBM by proteome analysis. PBM was purified from root nodules by an aqueous polymer two-phase system. Extracted proteins were subjected to a global trypsin digest. The peptides were separated by nanoscale liquid chromatography and analyzed by tandem mass spectrometry. Searching the nonredundant protein database and the green plant expressed sequence tag database using the tandem mass spectrometry data identified approximately 94 proteins, a number far exceeding the number of proteins reported for the PBM hitherto. In particular, a number of membrane proteins like transporters for sugars and sulfate; endomembrane-associated proteins such as GTP-binding proteins and vesicle receptors; and proteins involved in signaling, for example, receptor kinases, calmodulin, 14-3-3 proteins, and pathogen response-related proteins, including a so-called HIR protein, were detected. Several ATPases and aquaporins were present, indicating a more complex situation than previously thought. In addition, the unexpected presence of a number of proteins known to be located in other compartments was observed. Two characteristic protein complexes obtained from native gel electrophoresis of total PBM proteins were also analyzed. Together, the results identified specific proteins at the PBM involved in important physiological processes and localized proteins known from nodule-specific expressed sequence tag databases to the PBM. PMID:12644660

  18. Chromosomal and symbiotic relationships of rhizobia nodulating Medicago truncatula and M. laciniata.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    MultiLocus Sequence Typing (MLST) is a sequence-based method used to characterize bacterial genomes. This method was used to examine the genetic structure of Medicago-nodulating rhizobia at the Amra site, which is located in an arid region of Tunisia. Here the annual medics M. laciniata and M. tru...

  19. Symbiotic Efficiency of Native Rhizobia Nodulating Common Bean (Phaseolus vulgaris L.) in Soils of Western Kenya

    PubMed Central

    Kawaka, Fanuel; Dida, Mathews M.; Opala, Peter A.; Ombori, Omwoyo; Maingi, John; Osoro, Newton; Muthini, Morris; Amoding, Alice; Mukaminega, Dative; Muoma, John

    2014-01-01

    This study was conducted to determine the abundance and symbiotic efficiency of native rhizobia nodulating common bean in Kisumu and Kakamega, Kenya. Soil sampling was carried out in three farms that had been used for growing common bean for at least two seasons and one fallow land with no known history of growing common bean or inoculation. Abundance of soil rhizobia and symbiotic efficiency (SE) were determined in a greenhouse experiment. Native rhizobia populations ranged from 3.2 × 101 to 3.5 × 104 cells per gram of soil. Pure bacterial cultures isolated from fresh and healthy root nodules exhibited typical characteristics of Rhizobium sp. on yeast extract mannitol agar media supplemented with Congo red. Bean inoculation with the isolates significantly (p < 0.05) increased the shoot dry weight and nitrogen (N) concentration and content. The SE of all the native rhizobia were higher when compared to a reference strain, CIAT 899 (67%), and ranged from 74% to 170%. Four isolates had SE above a second reference strain, Strain 446 (110%). Our results demonstrate the presence of native rhizobia that are potentially superior to the commercial inoculants. These can be exploited to enhance bean inoculation programmes in the region. PMID:27355005

  20. Phyllobacterium loti sp. nov. isolated from nodules of Lotus corniculatus

    PubMed Central

    Sánchez, Maximo; Ramírez-Bahena, Martha-Helena; Peix, Alvaro; Lorite, María J.; Sanjuán, Juan; Monza, Jorge

    2014-01-01

    Strain S658T was isolated from a Lotus corniculatus nodule in a soil sample obtained in Uruguay. Phylogenetic analysis of the 16S rRNA gene and atpD gene showed that this strain clustered within the genus Phyllobacterium. The closest related species was, in both cases, Phyllobacterium trifolii PETP02T with 99.8 % sequence similarity in the 16S rRNA gene and 96.1 % in the atpD gene. The 16S rRNA gene contains an insert at the beginning of the sequence that has no similarities with other inserts present in the same gene in described rhizobial species. Ubiquinone Q-10 was the only quinone detected. Strain S658T differed from its closest relatives through its growth in diverse culture conditions and in the assimilation of several carbon sources. It was not able to reproduce nodules in Lotus corniculatus. The results of DNA–DNA hybridization, phenotypic tests and fatty acid analyses confirmed that this strain should be classified as a representative of a novel species of the genus Phyllobacterium, for which the name Phyllobacterium loti sp. nov. is proposed. The type strain is S658T( = LMG 27289T = CECT 8230T). PMID:24271211

  1. The REL3-mediated TAS3 ta-siRNA pathway integrates auxin and ethylene signaling to regulate nodulation in Lotus japonicus.

    PubMed

    Li, Xiaolin; Lei, Mingjuan; Yan, Zhongyuan; Wang, Qi; Chen, Aimin; Sun, Jie; Luo, Da; Wang, Yanzhang

    2014-01-01

    The ta-siRNA pathway is required for lateral organ development, including leaf patterning, flower differentiation and lateral root growth. Legumes can develop novel lateral root organs--nodules--resulting from symbiotic interactions with rhizobia. However, ta-siRNA regulation in nodule formation remains unknown. To explore ta-siRNA regulation in nodule formation, we investigated the roles of REL3, a key component of TAS3 ta-siRNA biogenesis, during nodulation in Lotus japonicus. We characterized the symbiotic phenotypes of the TAS3 ta-siRNA defective rel3 mutant, and analyzed the responses of the rel3 mutant to auxin and ethylene in order to gain insight into TAS3 ta-siRNA regulation of nodulation. The rel3 mutant produced fewer pink nitrogen-fixing nodules, with substantially decreased infection frequency and nodule initiation. Moreover, the rel3 mutant was more resistant than wild-type to 1-naphthaleneacetic acid (NAA) and N-1-naphthylphthalamic acid (NPA) in root growth, and exhibited insensitivity to auxins but greater sensitivity to auxin transport inhibitors during nodulation. Furthermore, the rel3 mutant has enhanced root-specific ethylene sensitivity and altered responses to ethylene during nodulation; the low-nodulating phenotype of the rel3 mutant can be restored by ethylene synthesis inhibitor L-α-(2-aminoethoxyvinyl)-glycine (AVG) or action inhibitor Ag(+). The REL3-mediated TAS3 ta-siRNA pathway regulates nodulation by integrating ethylene and auxin signaling. PMID:24164597

  2. Genotypic alteration and competitive nodulation of Mesorhizobium muleiense against exotic chickpea rhizobia in alkaline soils.

    PubMed

    Zhang, Jun Jie; Yu, Tao; Lou, Kai; Mao, Pei Hong; Wang, En Tao; Chen, Wen Feng; Chen, Wen Xin

    2014-10-01

    Mesorhizobium muleiense, Mesorhizobium mediterraneum and Mesorhizobium ciceri are chickpea (Cicer arietinum L.) rhizobia that share a high similarity of the symbiotic genes nodC and nifH, but they have different geographic distributions. M. muleiense has been isolated and found only in alkaline soils of Xinjiang, China, whereas the other two strains have been found in the Mediterranean and India. To investigate the species stability of M. muleiense during natural evolution and its capability of competitive nodulation against the other two exotic species, re-sampling of nodules in the field and competition experiments between the three species were conducted. The results showed that the predominant microsymbiont associated with chickpea grown in Xinjiang was still M. muleiense, but the predominant genotypes of M. muleiense had changed significantly during the four years since a previous survey. The data also showed that M. mediterraneum and M. ciceri were more competitive than the residential strain of M. muleiense CCBAU 83963(T) in sterilized vermiculite or soils from Xinjiang. However, in non-sterilized soils, M. muleiense was the predominant nodule occupier. These results indicated that natural or adapting evolution of M. muleiense was occurring in fields subjected to changing environmental factors. In addition, the biogeography and symbiotic associations of rhizobia with their host legumes were also influenced by biological factors in the soil, such as indigenous rhizobia and other organisms. PMID:25123757

  3. Comparative genomics of rhizobia nodulating soybean suggests extensive recruitment of lineage-specific genes in adaptations

    PubMed Central

    Tian, Chang Fu; Zhou, Yuan Jie; Zhang, Yan Ming; Li, Qin Qin; Zhang, Yun Zeng; Li, Dong Fang; Wang, Shuang; Wang, Jun; Gilbert, Luz B.; Li, Ying Rui; Chen, Wen Xin

    2012-01-01

    The rhizobium–legume symbiosis has been widely studied as the model of mutualistic evolution and the essential component of sustainable agriculture. Extensive genetic and recent genomic studies have led to the hypothesis that many distinct strategies, regardless of rhizobial phylogeny, contributed to the varied rhizobium–legume symbiosis. We sequenced 26 genomes of Sinorhizobium and Bradyrhizobium nodulating soybean to test this hypothesis. The Bradyrhizobium core genome is disproportionally enriched in lipid and secondary metabolism, whereas several gene clusters known to be involved in osmoprotection and adaptation to alkaline pH are specific to the Sinorhizobium core genome. These features are consistent with biogeographic patterns of these bacteria. Surprisingly, no genes are specifically shared by these soybean microsymbionts compared with other legume microsymbionts. On the other hand, phyletic patterns of 561 known symbiosis genes of rhizobia reflected the species phylogeny of these soybean microsymbionts and other rhizobia. Similar analyses with 887 known functional genes or the whole pan genome of rhizobia revealed that only the phyletic distribution of functional genes was consistent with the species tree of rhizobia. Further evolutionary genetics revealed that recombination dominated the evolution of core genome. Taken together, our results suggested that faithfully vertical genes were rare compared with those with history of recombination including lateral gene transfer, although rhizobial adaptations to symbiotic interactions and other environmental conditions extensively recruited lineage-specific shell genes under direct or indirect control through the speciation process. PMID:22586130

  4. Diversity of Rhizobia Nodulating Phaseolus vulgaris L. in Two Kenyan Soils with Contrasting pHs

    PubMed Central

    Anyango, B.; Wilson, K. J.; Beynon, J. L.; Giller, K. E.

    1995-01-01

    Rhizobia were isolated from two Kenyan soils with pHs of 4.5 and 6.8 and characterized on the basis of their host ranges for nodulation and nitrogen fixation, colony morphologies, restriction fragment fingerprints, and hybridization with a nifH probe. The populations of rhizobia nodulating Phaseolus vulgaris in the two soils were similar in numbers and in effectiveness of N(inf2) fixation but were markedly different in composition. The population in the Naivasha soil (pH 6.8) was dominated by isolates specific in host range for nodulation to P. vulgaris; these all had multiple copies, in most cases four, of the structural nitrogenase gene nifH. Only one of the isolates from this soil formed effective nodules on Leucaena leucocephala, and this isolate had only a single copy of nifH. By contrast, the population in the acid Daka-ini soil (pH 4.5) was composed largely of broad-host-range isolates which had single copies of nifH. The isolates from the Daka-ini soil which were specific to P. vulgaris generally had three copies of nifH, although one isolate had only two copies. These rhizobial isolates are indigenous to Kenyan soils and yet have marked similarities to previously described Rhizobium species from other continents. PMID:16535165

  5. A Novel Ankyrin-Repeat Membrane Protein, IGN1, Is Required for Persistence of Nitrogen-Fixing Symbiosis in Root Nodules of Lotus japonicus1[OA

    PubMed Central

    Kumagai, Hirotaka; Hakoyama, Tsuneo; Umehara, Yosuke; Sato, Shusei; Kaneko, Takakazu; Tabata, Satoshi; Kouchi, Hiroshi

    2007-01-01

    Nitrogen-fixing symbiosis of legume plants with Rhizobium bacteria is established through complex interactions between two symbiotic partners. Similar to the mutual recognition and interactions at the initial stages of symbiosis, nitrogen fixation activity of rhizobia inside root nodules of the host legume is also controlled by specific interactions during later stages of nodule development. We isolated a novel Fix− mutant, ineffective greenish nodules 1 (ign1), of Lotus japonicus, which forms apparently normal nodules containing endosymbiotic bacteria, but does not develop nitrogen fixation activity. Map-based cloning of the mutated gene allowed us to identify the IGN1 gene, which encodes a novel ankyrin-repeat protein with transmembrane regions. IGN1 expression was detected in all organs of L. japonicus and not enhanced in the nodulation process. Immunoanalysis, together with expression analysis of a green fluorescent protein-IGN1 fusion construct, demonstrated localization of the IGN1 protein in the plasma membrane. The ign1 nodules showed extremely rapid premature senescence. Irregularly enlarged symbiosomes with multiple bacteroids were observed at early stages (8–9 d post inoculation) of nodule formation, followed by disruption of the symbiosomes and disintegration of nodule infected cell cytoplasm with aggregation of the bacteroids. Although the exact biochemical functions of the IGN1 gene are still to be elucidated, these results indicate that IGN1 is required for differentiation and/or persistence of bacteroids and symbiosomes, thus being essential for functional symbiosis. PMID:17277093

  6. New aspect of plant–rhizobia interaction: Alkaloid biosynthesis in Crotalaria depends on nodulation

    PubMed Central

    Irmer, Simon; Podzun, Nora; Langel, Dorothee; Heidemann, Franziska; Kaltenegger, Elisabeth; Schemmerling, Brigitte; Geilfus, Christoph-Martin; Zörb, Christian; Ober, Dietrich

    2015-01-01

    Infection of legume hosts by rhizobial bacteria results in the formation of a specialized organ, the nodule, in which atmospheric nitrogen is reduced to ammonia. Nodulation requires the reprogramming of the plant cell, allowing the microsymbiont to enter the plant tissue in a highly controlled manner. We have found that, in Crotalaria (Fabaceae), this reprogramming is associated with the biosynthesis of pyrrolizidine alkaloids (PAs). These compounds are part of the plant’s chemical defense against herbivores and cannot be regarded as being functionally involved in the symbiosis. PAs in Crotalaria are detectable only when the plants form nodules after infection with their rhizobial partner. The identification of a plant-derived sequence encoding homospermidine synthase (HSS), the first pathway-specific enzyme of PA biosynthesis, suggests that the plant and not the microbiont is the producer of PAs. Transcripts of HSS are detectable exclusively in the nodules, the tissue with the highest concentration of PAs, indicating that PA biosynthesis is restricted to the nodules and that the nodules are the source from which the alkaloids are transported to the above ground parts of the plant. The link between nodulation and the biosynthesis of nitrogen-containing alkaloids in Crotalaria highlights a further facet of the effect of symbiosis with rhizobia on the ecologically important trait of the plant’s chemical defense. PMID:25775562

  7. Genetic diversity and community structure of rhizobia nodulating Sesbania cannabina in saline-alkaline soils.

    PubMed

    Li, Yan; Li, Xiangyue; Liu, Yajing; Wang, En Tao; Ren, Chenggang; Liu, Wei; Xu, Hualing; Wu, Hailong; Jiang, Nan; Li, Yunzhao; Zhang, Xiaoli; Xie, Zhihong

    2016-05-01

    Sesbania cannabina is a plant that grows naturally along the seashores in Rudong County, China (RDC) and it has been introduced into the Yellow River Delta (YRD) as a pioneer plant to improve the saline-alkaline soils. In order to investigate the diversity of S. cannabina rhizobia in these soils, a total of 198 rhizobial isolates were characterized and phylogenetic trees were constructed based on data from multilocus sequence analysis (MLSA) of the housekeeping genes recA, atpD and glnII, as well as 16S rRNA. Symbiotic features were also studied by establishing the phylogeny of the symbiotic genes nodA and nifH, and by performing nodulation assays. The isolates had highly conserved symbiotic genes and were classified into nine genospecies belonging to the genera Ensifer, Agrobacterium, Neorhizobium and Rhizobium. A unique community structure was detected in the rhizobia associated with S. cannabina in the saline-alkaline soils that was characterized by five novel genospecies and four defined species. In addition, Ensifer sp. I was the predominant rhizobia in YRD, whereas Ensifer meliloti and Neorhizobium huautlense were the dominant species in RDC. Therefore, the study demonstrated for the first time that this plant strongly selected the symbiotic gene background but not the genomic background of its microsymbionts. In addition, biogeographic patterns existed in the rhizobial populations associated with S. cannabina, which were mainly correlated with pH and salinity, as well as the mineral nutrient contents. This study provided novel information concerning the interaction between soil conditions, host plant and rhizobia, in addition to revealing the diversity of S. cannabina rhizobia in saline-alkaline soils. PMID:27061259

  8. The SNARE Protein SYP71 Expressed in Vascular Tissues Is Involved in Symbiotic Nitrogen Fixation in Lotus japonicus Nodules1[W][OA

    PubMed Central

    Hakoyama, Tsuneo; Oi, Ryo; Hazuma, Kazuya; Suga, Eri; Adachi, Yuka; Kobayashi, Mayumi; Akai, Rie; Sato, Shusei; Fukai, Eigo; Tabata, Satoshi; Shibata, Satoshi; Wu, Guo-Jiang; Hase, Yoshihiro; Tanaka, Atsushi; Kawaguchi, Masayoshi; Kouchi, Hiroshi; Umehara, Yosuke; Suganuma, Norio

    2012-01-01

    Soluble N-Ethylmaleimide Sensitive Factor Attachment Protein Receptor (SNARE) proteins are crucial for signal transduction and development in plants. Here, we investigate a Lotus japonicus symbiotic mutant defective in one of the SNARE proteins. When in symbiosis with rhizobia, the growth of the mutant was retarded compared with that of the wild-type plant. Although the mutant formed nodules, these exhibited lower nitrogen fixation activity than the wild type. The rhizobia were able to invade nodule cells, but enlarged symbiosomes were observed in the infected cells. The causal gene, designated LjSYP71 (for L. japonicus syntaxin of plants71), was identified by map-based cloning and shown to encode a Qc-SNARE protein homologous to Arabidopsis (Arabidopsis thaliana) SYP71. LjSYP71 was expressed ubiquitously in shoot, roots, and nodules, and transcripts were detected in the vascular tissues. In the mutant, no other visible defects in plant morphology were observed. Furthermore, in the presence of combined nitrogen, the mutant plant grew almost as well as the wild type. These results suggest that the vascular tissues expressing LjSYP71 play a pivotal role in symbiotic nitrogen fixation in L. japonicus nodules. PMID:22858633

  9. Rhizobial gibberellin negatively regulates host nodule number.

    PubMed

    Tatsukami, Yohei; Ueda, Mitsuyoshi

    2016-01-01

    In legume-rhizobia symbiosis, the nodule number is controlled to ensure optimal growth of the host. In Lotus japonicus, the nodule number has been considered to be tightly regulated by host-derived phytohormones and glycopeptides. However, we have discovered a symbiont-derived phytohormonal regulation of nodule number in Mesorhizobium loti. In this study, we found that M. loti synthesized gibberellic acid (GA) under symbiosis. Hosts inoculated with a GA-synthesis-deficient M. loti mutant formed more nodules than those inoculated with the wild-type form at four weeks post inoculation, indicating that GA from already-incorporated rhizobia prevents new nodule formation. Interestingly, the genes for GA synthesis are only found in rhizobial species that inhabit determinate nodules. Our findings suggest that the already-incorporated rhizobia perform GA-associated negative regulation of nodule number to prevent delayed infection by other rhizobia. PMID:27307029

  10. Rhizobial gibberellin negatively regulates host nodule number

    PubMed Central

    Tatsukami, Yohei; Ueda, Mitsuyoshi

    2016-01-01

    In legume–rhizobia symbiosis, the nodule number is controlled to ensure optimal growth of the host. In Lotus japonicus, the nodule number has been considered to be tightly regulated by host-derived phytohormones and glycopeptides. However, we have discovered a symbiont-derived phytohormonal regulation of nodule number in Mesorhizobium loti. In this study, we found that M. loti synthesized gibberellic acid (GA) under symbiosis. Hosts inoculated with a GA-synthesis-deficient M. loti mutant formed more nodules than those inoculated with the wild-type form at four weeks post inoculation, indicating that GA from already-incorporated rhizobia prevents new nodule formation. Interestingly, the genes for GA synthesis are only found in rhizobial species that inhabit determinate nodules. Our findings suggest that the already-incorporated rhizobia perform GA-associated negative regulation of nodule number to prevent delayed infection by other rhizobia. PMID:27307029

  11. Nitrogen-Fixing Nodules Are an Important Source of Reduced Sulfur, Which Triggers Global Changes in Sulfur Metabolism in Lotus japonicus.

    PubMed

    Kalloniati, Chrysanthi; Krompas, Panagiotis; Karalias, Georgios; Udvardi, Michael K; Rennenberg, Heinz; Herschbach, Cornelia; Flemetakis, Emmanouil

    2015-09-01

    We combined transcriptomic and biochemical approaches to study rhizobial and plant sulfur (S) metabolism in nitrogen (N) fixing nodules (Fix(+)) of Lotus japonicus, as well as the link of S-metabolism to symbiotic nitrogen fixation and the effect of nodules on whole-plant S-partitioning and metabolism. Our data reveal that N-fixing nodules are thiol-rich organs. Their high adenosine 5'-phosphosulfate reductase activity and strong (35)S-flux into cysteine and its metabolites, in combination with the transcriptional upregulation of several rhizobial and plant genes involved in S-assimilation, highlight the function of nodules as an important site of S-assimilation. The higher thiol content observed in nonsymbiotic organs of N-fixing plants in comparison to uninoculated plants could not be attributed to local biosynthesis, indicating that nodules are an important source of reduced S for the plant, which triggers whole-plant reprogramming of S-metabolism. Enhanced thiol biosynthesis in nodules and their impact on the whole-plant S-economy are dampened in plants nodulated by Fix(-) mutant rhizobia, which in most respects metabolically resemble uninoculated plants, indicating a strong interdependency between N-fixation and S-assimilation. PMID:26296963

  12. Nitrogen-Fixing Nodules Are an Important Source of Reduced Sulfur, Which Triggers Global Changes in Sulfur Metabolism in Lotus japonicus

    PubMed Central

    Kalloniati, Chrysanthi; Krompas, Panagiotis; Udvardi, Michael K.; Flemetakis, Emmanouil

    2015-01-01

    We combined transcriptomic and biochemical approaches to study rhizobial and plant sulfur (S) metabolism in nitrogen (N) fixing nodules (Fix+) of Lotus japonicus, as well as the link of S-metabolism to symbiotic nitrogen fixation and the effect of nodules on whole-plant S-partitioning and metabolism. Our data reveal that N-fixing nodules are thiol-rich organs. Their high adenosine 5′-phosphosulfate reductase activity and strong 35S-flux into cysteine and its metabolites, in combination with the transcriptional upregulation of several rhizobial and plant genes involved in S-assimilation, highlight the function of nodules as an important site of S-assimilation. The higher thiol content observed in nonsymbiotic organs of N-fixing plants in comparison to uninoculated plants could not be attributed to local biosynthesis, indicating that nodules are an important source of reduced S for the plant, which triggers whole-plant reprogramming of S-metabolism. Enhanced thiol biosynthesis in nodules and their impact on the whole-plant S-economy are dampened in plants nodulated by Fix− mutant rhizobia, which in most respects metabolically resemble uninoculated plants, indicating a strong interdependency between N-fixation and S-assimilation. PMID:26296963

  13. Phenotypic and genomic characteristics of rhizobia isolated from Genista tinctoria root nodules.

    PubMed

    Kalita, Michał; Małek, Wanda

    2004-11-01

    Forty three rhizobial strains isolated from root nodules of Genista tinctoria growing in England, Ukraine, and Poland were compared with 21 representatives of the recognized rhizobial species and two unclassified Bradyrhizobium sp. (Lupinus) strains by performing a numerical analysis of 102 phenotypic features and with the reference bradyrhizobia by simplified AFLP analysis with one restriction enzyme PstI and one selective primer PstI-A. All Genista tinctoria microsymbionts were slow-growing bradyrhizobia with generation time of 10-14 h, acid tolerant, salt sensitive, and antibiotic resistant. Cluster analysis based on the phenotypic properties of all bacteria included, grouped dyer's broom rhizobia together with Bradyrhizobium strains, and classified them into three major phena according to their geographic origin. Genista tinctoria nodule isolates were separated into three clusters with the strain composition as in a phenogrouping by AFLP patterns. The presented results, suggest the relationship of G. tincoria microsymbionts to Bradyrhizobium species and show the usefulness of AFLP analysis for differentiation and classification of the studied rhizobia. PMID:15612629

  14. Lotus japonicus Clathrin Heavy Chain1 Is Associated with Rho-Like GTPase ROP6 and Involved in Nodule Formation1[OPEN

    PubMed Central

    Zhu, Maosheng; Duan, Liujiang; Yu, Haixiang; Chang, Xiaojun; Li, Li; Kang, Heng; Feng, Yong; Zhu, Hui; Hong, Zonglie

    2015-01-01

    Mechanisms underlying nodulation factor signaling downstream of the nodulation factor receptors (NFRs) have not been fully characterized. In this study, clathrin heavy chain1 (CHC1) was shown to interact with the Rho-Like GTPase ROP6, an interaction partner of NFR5 in Lotus japonicus. The CHC1 gene was found to be expressed constitutively in all plant tissues and induced in Mesorhizobium loti-infected root hairs and nodule primordia. When expressed in leaves of Nicotiana benthamiana, CHC1 and ROP6 were colocalized at the cell circumference and within cytoplasmic punctate structures. In M. loti-infected root hairs, the CHC protein was detected in cytoplasmic punctate structures near the infection pocket along the infection thread membrane and the plasma membrane of the host cells. Transgenic plants expressing the CHC1-Hub domain, a dominant negative effector of clathrin-mediated endocytosis, were found to suppress early nodulation gene expression and impair M. loti infection, resulting in reduced nodulation. Treatment with tyrphostin A23, an inhibitor of clathrin-mediated endocytosis of plasma membrane cargoes, had a similar effect on down-regulation of early nodulation genes. These findings show an important role of clathrin in the leguminous symbiosis with rhizobia. PMID:25717037

  15. COMPARISON OF RHIZOBIA THAT NODULATE MEDICAGO LACINIATA AND M. TRUNCATULA PRESENT IN A SINGLE TUNISIAN ARID SOIL.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rhizobia present in a single arid-region Tunisian soil that nodulate Medicago laciniata and M. truncatula were compared. All isolates, 40 from each host, probably were more closely related to S. meliloti than to S. medicae based on 16S rRNA PCR-RFLP. There was no apparent relationship between ...

  16. Application of Multilocus Sequence Typing To Study the Genetic Structure of Megaplasmids in Medicago-Nodulating Rhizobia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multilocus sequence typing (MLST) analysis was used to examine the relatedness and distribution of genotypic variants of the two large extrachromosomal replicons in Medicago-nodulating rhizobia (Sinorhizobium meliloti and S. medicae). One goal was to develop a strategy for the characterization of...

  17. Silencing the flavonoid pathway in Medicago truncatula inhibits root nodule formation and prevents auxin transport regulation by rhizobia.

    PubMed

    Wasson, Anton P; Pellerone, Flavia I; Mathesius, Ulrike

    2006-07-01

    Legumes form symbioses with rhizobia, which initiate the development of a new plant organ, the nodule. Flavonoids have long been hypothesized to regulate nodule development through their action as auxin transport inhibitors, but genetic proof has been missing. To test this hypothesis, we used RNA interference to silence chalcone synthase (CHS), the enzyme that catalyzes the first committed step of the flavonoid pathway, in Medicago truncatula. Agrobacterium rhizogenes transformation was used to create hairy roots that showed strongly reduced CHS transcript levels and reduced levels of flavonoids in silenced roots. Flavonoid-deficient roots were unable to initiate nodules, even though normal root hair curling was observed. Nodule formation and flavonoid accumulation could be rescued by supplementation of plants with the precursor flavonoids naringenin and liquiritigenin. The flavonoid-deficient roots showed increased auxin transport compared with control roots. Inoculation with rhizobia reduced auxin transport in control roots after 24 h, similar to the action of the auxin transport inhibitor N-(1-naphthyl)phthalamic acid (NPA). Rhizobia were unable to reduce auxin transport in flavonoid-deficient roots, even though NPA inhibited auxin transport. Our results present genetic evidence that root flavonoids are necessary for nodule initiation in M. truncatula and suggest that they act as auxin transport regulators. PMID:16751348

  18. Nodule Ultrastructure and Initial Growth of Anadenanthera peregrina (L.) Speg. var. falcata (Benth.) Altschul Plants Infected with Rhizobia

    PubMed Central

    GROSS, E.; CORDEIRO, L.; CAETANO, F. H.

    2002-01-01

    The anatomy and ultrastructure of root nodules of Anadenanthera peregrina var. falcata (Leguminosae‐Mimosoideae) were analysed, as was plant growth. To ensure that nodules developed, seedlings were inoculated with a mixture of six strains of rhizobia. Nodules were produced that differed in appearance—and probably also effectiveness—but their structure was similar and they showed characteristics typical of indeterminate nodules, such as persistent meristematic tissue and a gradient of cells at different stages of development. Many starch grains were present in inner cortex cells and interstitial cells of infected tissue. Infected cells were densely packed with bacteroids, which contained many poly‐β‐hydroxybutyrate granules. The high incidence of these granules, together with high levels of starch accumulation in interstitial cells, suggested low N2‐fixation efficiency of the rhizobia isolates used for inoculation. In the symbiosomes of early‐senescent infected cells, reticulum‐like structures, small vesicles and a fibrillar material were observed; these may be related to bacteroid degradation. In the cytoplasm of late‐senescent infected cells, many vesicles and membrane‐like structures were observed, probably associated with membrane degradation of bacteroids and peribacteroids. The total biomass of plants inoculated with rhizobia was low and their xylopodia and shoots had low levels of N compared with non‐inoculated plants fertilized with ammonium nitrate. However, inoculated plants did not show N‐deficiency symptoms and grew better than non‐inoculated plants without N fertilization. These growth results, together with ultrastructural observations of nodules, suggest that nitrogen fixation of rhizobia isolates associated with Anadenanthera peregrina var. falcata roots is poor. PMID:12197515

  19. CYTOKININ OXIDASE/DEHYDROGENASE3 Maintains Cytokinin Homeostasis during Root and Nodule Development in Lotus japonicus.

    PubMed

    Reid, Dugald E; Heckmann, Anne B; Novák, Ondřej; Kelly, Simon; Stougaard, Jens

    2016-02-01

    Cytokinins are required for symbiotic nodule development in legumes, and cytokinin signaling responses occur locally in nodule primordia and in developing nodules. Here, we show that the Lotus japonicus Ckx3 cytokinin oxidase/dehydrogenase gene is induced by Nod factor during the early phase of nodule initiation. At the cellular level, pCkx3::YFP reporter-gene studies revealed that the Ckx3 promoter is active during the first cortical cell divisions of the nodule primordium and in growing nodules. Cytokinin measurements in ckx3 mutants confirmed that CKX3 activity negatively regulates root cytokinin levels. Particularly, tZ and DHZ type cytokinins in both inoculated and uninoculated roots were elevated in ckx3 mutants, suggesting that these are targets for degradation by the CKX3 cytokinin oxidase/dehydrogenase. The effect of CKX3 on the positive and negative roles of cytokinin in nodule development, infection and regulation was further clarified using ckx3 insertion mutants. Phenotypic analysis indicated that ckx3 mutants have reduced nodulation, infection thread formation and root growth. We also identify a role for cytokinin in regulating nodulation and nitrogen fixation in response to nitrate as ckx3 phenotypes are exaggerated at increased nitrate levels. Together, these findings show that cytokinin accumulation is tightly regulated during nodulation in order to balance the requirement for cell divisions with negative regulatory effects of cytokinin on infection events and root development. PMID:26644503

  20. Leguminous plants: inventors of root nodules to accommodate symbiotic bacteria.

    PubMed

    Suzaki, Takuya; Yoro, Emiko; Kawaguchi, Masayoshi

    2015-01-01

    Legumes and a few other plant species can establish a symbiotic relationship with nitrogen-fixing rhizobia, which enables them to survive in a nitrogen-deficient environment. During the course of nodulation, infection with rhizobia induces the dedifferentiation of host cells to form primordia of a symbiotic organ, the nodule, which prepares plants to accommodate rhizobia in host cells. While these nodulation processes are known to be genetically controlled by both plants and rhizobia, recent advances in studies on two model legumes, Lotus japonicus and Medicago truncatula, have provided great insight into the underlying plant-side molecular mechanism. In this chapter, we review such knowledge, with particular emphasis on two key processes of nodulation, nodule development and rhizobial invasion. PMID:25805123

  1. Effect of Co-Inoculation with Mycorrhiza and Rhizobia on the Nodule Trehalose Content of Different Bean Genotypes

    PubMed Central

    Ballesteros-Almanza, L; Altamirano-Hernandez, J; Peña-Cabriales, J.J; Santoyo, G; Sanchez-Yañez, J.M; Valencia-Cantero, E; Macias-Rodriguez, L; Lopez-Bucio, J; Cardenas-Navarro, R; Farias-Rodriguez, R

    2010-01-01

    Studies on Rhizobium-legume symbiosis show that trehalose content in nodules under drought stress correlates positively with an increase in plant tolerance to this stress. Fewer reports describe trehalose accumulation in mycorrhiza where, in contrast with rhizobia, there is no flux of carbohydrates from the microsymbiont to the plant. However, the trehalose dynamics in the Mycorrhiza-Rhizobium-Legume tripartite symbiosis is unknown. The present study explores the role of this tripartite symbiosis in the trehalose content of nodules grown under contrasting moisture conditions. Three wild genotypes (P. filiformis, P. acutifolis and P. vulgaris) and two commercial genotypes of Phaseolus vulgaris (Pinto villa and Flor de Mayo) were used. Co-inoculation treatments were conducted with Glomus intraradices and a mixture of seven native rhizobial strains, and trehalose content was determined by GC/MS. The results showed a negative effect of mycorrhizal inoculation on nodule development, as mycorrhized plants showed fewer nodules and lower nodule dry weight compared to plants inoculated only with Rhizobium. Mycorrhizal colonization was also higher in plants inoculated only with Glomus as compared to plants co-inoculated with both microsymbionts. In regard to trehalose, co-inoculation negatively affects its accumulation in the nodules of each genotype tested. However, the correlation analysis showed a significantly positive correlation between mycorrhizal colonization and nodule trehalose content. PMID:21253462

  2. Nodulation of cowpeas and survival of cowpeas Rhizobia in acid, aluminum-rich soils. [Vigna unguiculata; Rhizobium

    SciTech Connect

    Hartel, P.G.; Whelan, A.M.; Alexander, M.

    1983-01-01

    A study was undertaken to determine whether the reduced nodulation of cowpeas (Vigna unguiculata (L.) Walp) grown in certain acid, Alrich soils resulted from the poor survival of the potentially infective rhizobia. Two strains of Rhizobium capable of nodulating cowpeas were used. The lowest pH for growth in defined liquid medium was 4.2 for one strain and 3.9 for the other. Only the latter was Al tolerant and could grow in a defined liquid medium containing 50 ..mu..M KAl(SO/sub 4/)/sub 2/. The survival of the bacteria and their ability to nodulate cowpeas in three soils were measured after the soils were amended with Ca or Al salts to give pH values ranging from 5.7 to 4.1 and extractable-Al concentrations from < 0.1 to 3.7 cmol(p/sup +/)/kg of soil. Only small differences in survival in 7 or 8 weeks were noted between the two strains. Plants inoculated with the Al-sensitive strain bore significantly fewer nodules in the more acid, Al-rich soils than in the same soils with higher pH values and less extractable Al. No significant reduction in nodule number was evident for plants inoculated with the Al-tolerant strain and grown in the more acid, Al-rich soils compared to cowpeas grown in the same soils with higher pH values and less extractable Al. It is suggested that the Al content of soil is not a major factor in the survival of cowpea rhizobia but that it does have a significant effect on nodulation. 24 references, 3 figures, 2 tables.

  3. Medicago truncatula natural resistance-associated macrophage Protein1 is required for iron uptake by rhizobia-infected nodule cells.

    PubMed

    Tejada-Jiménez, Manuel; Castro-Rodríguez, Rosario; Kryvoruchko, Igor; Lucas, M Mercedes; Udvardi, Michael; Imperial, Juan; González-Guerrero, Manuel

    2015-05-01

    Iron is critical for symbiotic nitrogen fixation (SNF) as a key component of multiple ferroproteins involved in this biological process. In the model legume Medicago truncatula, iron is delivered by the vasculature to the infection/maturation zone (zone II) of the nodule, where it is released to the apoplast. From there, plasma membrane iron transporters move it into rhizobia-containing cells, where iron is used as the cofactor of multiple plant and rhizobial proteins (e.g. plant leghemoglobin and bacterial nitrogenase). MtNramp1 (Medtr3g088460) is the M. truncatula Natural Resistance-Associated Macrophage Protein family member, with the highest expression levels in roots and nodules. Immunolocalization studies indicate that MtNramp1 is mainly targeted to the plasma membrane. A loss-of-function nramp1 mutant exhibited reduced growth compared with the wild type under symbiotic conditions, but not when fertilized with mineral nitrogen. Nitrogenase activity was low in the mutant, whereas exogenous iron and expression of wild-type MtNramp1 in mutant nodules increased nitrogen fixation to normal levels. These data are consistent with a model in which MtNramp1 is the main transporter responsible for apoplastic iron uptake by rhizobia-infected cells in zone II. PMID:25818701

  4. Abundance and diversity of soybean-nodulating rhizobia in black soil are impacted by land use and crop management.

    PubMed

    Yan, Jun; Han, Xiao Zeng; Ji, Zhao Jun; Li, Yan; Wang, En Tao; Xie, Zhi Hong; Chen, Wen Feng

    2014-09-01

    To investigate the effects of land use and crop management on soybean rhizobial communities, 280 nodule isolates were trapped from 7 fields with different land use and culture histories. Besides the known Bradyrhizobium japonicum, three novel genospecies were isolated from these fields. Grassland (GL) maintained a higher diversity of soybean bradyrhizobia than the other cultivation systems. Two genospecies (Bradyrhizobium spp. I and III) were distributed widely in all treatments, while Bradyrhizobium sp. II was found only in GL treatment. Cultivation with soybeans increased the rhizobial abundance and diversity, except for the soybean monoculture (S-S) treatment. In monoculture systems, soybeans favored Bradyrhizobium sp. I, while maize and wheat favored Bradyrhizobium sp. III. Fertilization decreased the rhizobial diversity indexes but did not change the species composition. The organic carbon (OC) and available phosphorus (AP) contents and pH were the main soil parameters positively correlated with the distribution of Bradyrhizobium spp. I and II and Bradyrhizobium japonicum and negatively correlated with Bradyrhizobium sp. III. These results revealed that different land uses and crop management could not only alter the diversity and abundance of soybean rhizobia, but also change interactions between rhizobia and legume or nonlegume plants, which offered novel information about the biogeography of rhizobia. PMID:24951780

  5. Abundance and Diversity of Soybean-Nodulating Rhizobia in Black Soil Are Impacted by Land Use and Crop Management

    PubMed Central

    Yan, Jun; Ji, Zhao Jun; Li, Yan; Wang, En Tao; Xie, Zhi Hong

    2014-01-01

    To investigate the effects of land use and crop management on soybean rhizobial communities, 280 nodule isolates were trapped from 7 fields with different land use and culture histories. Besides the known Bradyrhizobium japonicum, three novel genospecies were isolated from these fields. Grassland (GL) maintained a higher diversity of soybean bradyrhizobia than the other cultivation systems. Two genospecies (Bradyrhizobium spp. I and III) were distributed widely in all treatments, while Bradyrhizobium sp. II was found only in GL treatment. Cultivation with soybeans increased the rhizobial abundance and diversity, except for the soybean monoculture (S-S) treatment. In monoculture systems, soybeans favored Bradyrhizobium sp. I, while maize and wheat favored Bradyrhizobium sp. III. Fertilization decreased the rhizobial diversity indexes but did not change the species composition. The organic carbon (OC) and available phosphorus (AP) contents and pH were the main soil parameters positively correlated with the distribution of Bradyrhizobium spp. I and II and Bradyrhizobium japonicum and negatively correlated with Bradyrhizobium sp. III. These results revealed that different land uses and crop management could not only alter the diversity and abundance of soybean rhizobia, but also change interactions between rhizobia and legume or nonlegume plants, which offered novel information about the biogeography of rhizobia. PMID:24951780

  6. Nodule morphology, symbiotic specificity and association with unusual rhizobia are distinguishing features of the genus Listia within the southern African crotalarioid clade Lotononis s.l.

    PubMed Central

    Ardley, Julie K.; Reeve, Wayne G.; O'Hara, Graham W.; Yates, Ron J.; Dilworth, Michael J.; Howieson, John G.

    2013-01-01

    Background and Aims The legume clade Lotononis sensu lato (s.l.; tribe Crotalarieae) comprises three genera: Listia, Leobordea and Lotononis sensu stricto (s.s.). Listia species are symbiotically specific and form lupinoid nodules with rhizobial species of Methylobacterium and Microvirga. This work investigated whether these symbiotic traits were confined to Listia by determining the ability of rhizobial strains isolated from species of Lotononis s.l. to nodulate Listia, Leobordea and Lotononis s.s. hosts and by examining the morphology and structure of the resulting nodules. Methods Rhizobia were characterized by sequencing their 16S rRNA and nodA genes. Nodulation and N2 fixation on eight taxonomically diverse Lotononis s.l. species were determined in glasshouse trials. Nodules of all hosts, and the process of infection and nodule initiation in Listia angolensis and Listia bainesii, were examined by light microscopy. Key Results Rhizobia associated with Lotononis s.l. were phylogenetically diverse. Leobordea and Lotononis s.s. isolates were most closely related to Bradyrhizobium spp., Ensifer meliloti, Mesorhizobium tianshanense and Methylobacterium nodulans. Listia angolensis formed effective nodules only with species of Microvirga. Listia bainesii nodulated only with pigmented Methylobacterium. Five lineages of nodA were found. Listia angolensis and L. bainesii formed lupinoid nodules, whereas nodules of Leobordea and Lotononis s.s. species were indeterminate. All effective nodules contained uniformly infected central tissue. Listia angolensis and L. bainesii nodule initials occurred on the border of the hypocotyl and along the tap root, and nodule primordia developed in the outer cortical layer. Neither root hair curling nor infection threads were seen. Conclusions Two specificity groups occur within Lotononis s.l.: Listia species are symbiotically specific, while species of Leobordea and Lotononis s.s. are generally promiscuous and interact with rhizobia of

  7. Genetic Diversity and Phylogeny of Rhizobia That Nodulate Acacia spp. in Morocco Assessed by Analysis of rRNA Genes

    PubMed Central

    Khbaya, Bouchaib; Neyra, Marc; Normand, Philippe; Zerhari, Karim; Filali-Maltouf, Abdelkarim

    1998-01-01

    Forty rhizobia nodulating four Acacia species (A. gummifera, A. raddiana, A. cyanophylla, and A. horrida) were isolated from different sites in Morocco. These rhizobia were compared by analyzing both the 16S rRNA gene (rDNA) and the 16S-23S rRNA spacer by PCR with restriction fragment length polymorphism (RFLP) analysis. Analysis of the length of 16S-23S spacer showed a considerable diversity within these microsymbionts, but RFLP analysis of the amplified spacer revealed no additional heterogeneity. Three clusters were identified when 16S rDNA analysis was carried out. Two of these clusters include some isolates which nodulate, nonspecifically, the four Acacia species. These clusters, A and B, fit within the Sinorhizobium lineage and are closely related to S. meliloti and S. fredii, respectively. The third cluster appeared to belong to the Agrobacterium-Rhizobium galegae phylum and is more closely related to the Agrobacterium tumefaciens species. These relations were confirmed by sequencing a representative strain from each cluster. PMID:9835582

  8. Genetic diversity and symbiotic compatibility among rhizobial strains and Desmodium incanum and Lotus spp. plants

    PubMed Central

    Granada, Camille E.; Strochein, Marcos; Vargas, Luciano K.; Bruxel, Manuela; de Sá, Enilson Luiz Saccol; Passaglia, Luciane M.P.

    2014-01-01

    This work aimed to evaluate the symbiotic compatibility and nodulation efficiency of rhizobia isolated from Desmodium incanum, Lotus corniculatus, L. subbiflorus, L. uliginosus and L. glaber plants by cross-inoculation. Twelve reference strains and 21 native isolates of rhizobia were genetically analyzed by the BOX-PCR technique, which showed a high genetic diversity among the rhizobia studied. The isolates were also characterized based on their production of indolic compounds and siderophores, as well as on their tolerance to salinity. Fifteen of the 33 rhizobia analyzed were able to produce indolic compounds, whereas 13 produced siderophores. All the tested rhizobia were sensitive to high salinity, although some were able to grow in solutions of up to 2% NaCl. Most of the native rhizobia isolated from L. uliginosus were able to induce nodulation in all plant species studied. In a greenhouse experiment using both D. incanum and L. corniculatus plants, the rhizobia isolate UFRGS Lu2 promoted the greatest plant growth. The results demonstrate that there are native rhizobia in the soils of southern Brazil that have low host specificity and are able to induce nodulation and form active nodules in several plant species. PMID:25071405

  9. Genetic diversity and symbiotic compatibility among rhizobial strains and Desmodium incanum and Lotus spp. plants.

    PubMed

    Granada, Camille E; Strochein, Marcos; Vargas, Luciano K; Bruxel, Manuela; de Sá, Enilson Luiz Saccol; Passaglia, Luciane M P

    2014-06-01

    This work aimed to evaluate the symbiotic compatibility and nodulation efficiency of rhizobia isolated from Desmodium incanum, Lotus corniculatus, L. subbiflorus, L. uliginosus and L. glaber plants by cross-inoculation. Twelve reference strains and 21 native isolates of rhizobia were genetically analyzed by the BOX-PCR technique, which showed a high genetic diversity among the rhizobia studied. The isolates were also characterized based on their production of indolic compounds and siderophores, as well as on their tolerance to salinity. Fifteen of the 33 rhizobia analyzed were able to produce indolic compounds, whereas 13 produced siderophores. All the tested rhizobia were sensitive to high salinity, although some were able to grow in solutions of up to 2% NaCl. Most of the native rhizobia isolated from L. uliginosus were able to induce nodulation in all plant species studied. In a greenhouse experiment using both D. incanum and L. corniculatus plants, the rhizobia isolate UFRGS Lu2 promoted the greatest plant growth. The results demonstrate that there are native rhizobia in the soils of southern Brazil that have low host specificity and are able to induce nodulation and form active nodules in several plant species. PMID:25071405

  10. Rhizobia from Lanzarote, the Canary Islands, that nodulate Phaseolus vulgars have characteristics in common with Sinorhizobium meliloti isolates from mainland Spain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Common bean and Medicago rhizobia isolated from five locations on the island of Lanzarote, the Canary Islands, by partial analysis of 10 chromosomal genes were shown to exhibit close similarity to Sinorhizobium meliloti. Several bean isolates from Lanzarote, mainland Spain and Tunisia nodulated Leu...

  11. Does Lowering Glutamine Synthetase Activity in Nodules Modify Nitrogen Metabolism and Growth of Lotus japonicus?1

    PubMed Central

    Harrison, Judith; Pou de Crescenzo, Marie-Anne; Sené, Olivier; Hirel, Bertrand

    2003-01-01

    A cDNA encoding cytosolic glutamine synthetase (GS) from Lotus japonicus was fused in the antisense orientation relative to the nodule-specific LBC3 promoter of soybean (Glycine max) and introduced into L. japonicus via transformation with Agrobacterium tumefaciens. Among the 12 independent transformed lines into which the construct was introduced, some of them showed diminished levels of GS1 mRNA and lower levels of GS activity. Three of these lines were selected and their T1 progeny was further analyzed both for plant biomass production and carbon and nitrogen (N) metabolites content under symbiotic N-fixing conditions. Analysis of these plants revealed an increase in fresh weight in nodules, roots and shoots. The reduction in GS activity was found to correlate with an increase in amino acid content of the nodules, which was primarily due to an increase in asparagine content. Thus, this study supports the hypothesis that when GS becomes limiting, other enzymes (e.g. asparagine synthetase) that have the capacity to assimilate ammonium may be important in controlling the flux of reduced N in temperate legumes such as L. japonicus. Whether these alternative metabolic pathways are important in the control of plant biomass production still remains to be fully elucidated. PMID:12970491

  12. CYTOKININ OXIDASE/DEHYDROGENASE3 Maintains Cytokinin Homeostasis during Root and Nodule Development in Lotus japonicus1[OPEN

    PubMed Central

    Heckmann, Anne B.; Kelly, Simon

    2016-01-01

    Cytokinins are required for symbiotic nodule development in legumes, and cytokinin signaling responses occur locally in nodule primordia and in developing nodules. Here, we show that the Lotus japonicus Ckx3 cytokinin oxidase/dehydrogenase gene is induced by Nod factor during the early phase of nodule initiation. At the cellular level, pCkx3::YFP reporter-gene studies revealed that the Ckx3 promoter is active during the first cortical cell divisions of the nodule primordium and in growing nodules. Cytokinin measurements in ckx3 mutants confirmed that CKX3 activity negatively regulates root cytokinin levels. Particularly, tZ and DHZ type cytokinins in both inoculated and uninoculated roots were elevated in ckx3 mutants, suggesting that these are targets for degradation by the CKX3 cytokinin oxidase/dehydrogenase. The effect of CKX3 on the positive and negative roles of cytokinin in nodule development, infection and regulation was further clarified using ckx3 insertion mutants. Phenotypic analysis indicated that ckx3 mutants have reduced nodulation, infection thread formation and root growth. We also identify a role for cytokinin in regulating nodulation and nitrogen fixation in response to nitrate as ckx3 phenotypes are exaggerated at increased nitrate levels. Together, these findings show that cytokinin accumulation is tightly regulated during nodulation in order to balance the requirement for cell divisions with negative regulatory effects of cytokinin on infection events and root development. PMID:26644503

  13. A novel ARID DNA-binding protein interacts with SymRK and is expressed during early nodule development in Lotus japonicus.

    PubMed

    Zhu, Hui; Chen, Tao; Zhu, Maosheng; Fang, Qing; Kang, Heng; Hong, Zonglie; Zhang, Zhongming

    2008-09-01

    During the establishment of symbiosis in legume roots, the rhizobial Nod factor signal is perceived by the host cells via receptor-like kinases, including SymRK. The NODULE INCEPTION (NIN) gene in Lotus japonicus is required for rhizobial entry into root cells and for nodule organogenesis. We describe here a novel DNA-binding protein from L. japonicus, referred to as SIP1, because it was identified as a SymRK-interacting protein. SIP1 contains a conserved AT-rich interaction domain (ARID) and represents a unique member of the ARID-containing proteins in plants. The C terminus of SIP1 was found to be responsible for its interaction with the kinase domain of SymRK and for homodimerization in the absence of DNA. SIP1 specifically binds to the promoter of LjNIN but not to that of LjCBP1 (a calcium-binding protein gene), both of which are known to be inducible by Nod factors. SIP1 recognizes two of the three AT-rich domains present in the NIN gene promoter. Deletion of one of the AT-rich domains at the NIN promoter diminishes the binding of SIP1 to the NIN promoter. The protein is localized to the nuclei when expressed as a red fluorescence fusion protein in the onion (Allium cepa) epidermal cells. The SIP1 gene is expressed constitutively in the uninfected roots, and its expression levels are elevated after infection by Mesorhizobium loti. It is proposed that SIP1 may be required for the expression of NIN and involved in the initial communications between the rhizobia and the host root cells. PMID:18633121

  14. A Lotus japonicus beta-type carbonic anhydrase gene expression pattern suggests distinct physiological roles during nodule development.

    PubMed

    Flemetakis, Emmanouil; Dimou, Maria; Cotzur, Daniela; Aivalakis, Georgios; Efrose, Rodica C; Kenoutis, Christos; Udvardi, Michael; Katinakis, Panagiotis

    2003-08-25

    A full-length cDNA clone, designated Ljca1, coding for a beta-type carbonic anhydrase (CA; EC: 4.2.1.1) was isolated from a Lotus japonicus nodule cDNA library. Semi-quantitative RT-PCR analysis revealed that Ljca1 codes for a nodule-specific CA, transcripts of which accumulate at maximum levels in young nodules at 14 days post-infection (d.p.i.). In situ hybridization and immunolocalization revealed that Ljca1 transcripts and LjCA1 polypeptides were present at high levels in all cell types of young nodules. In contrast, in mature nodules both transcripts and polypeptides were confined in a few cell layers of the nodules inner cortex. However, the central infected tissue of both young and mature nodules exhibited high CA activity, indicating the presence of additional CA isoforms of plant and/or microbial origin. This was supported by the finding that a putative Mesorhizobium loti CA gene was transiently expressed during nodule development. In addition, the temporal and spatial accumulation of phosphoenolpyruvate carboxylase (PEPC; EC: 4.1.1.31) was determined by semi-quantitative RT-PCR and immunolocalization. The results suggest that LjCA1 might fulfill different physiological needs during L. japonicus nodule development. PMID:12932831

  15. Two microRNAs linked to nodule infection and nitrogen-fixing ability in the legume Lotus japonicus.

    PubMed

    De Luis, Ana; Markmann, Katharina; Cognat, Valérie; Holt, Dennis B; Charpentier, Myriam; Parniske, Martin; Stougaard, Jens; Voinnet, Olivier

    2012-12-01

    Legumes overcome nitrogen shortage by developing root nodules in which symbiotic bacteria fix atmospheric nitrogen in exchange for host-derived carbohydrates and mineral nutrients. Nodule development involves the distinct processes of nodule organogenesis, bacterial infection, and the onset of nitrogen fixation. These entail profound, dynamic gene expression changes, notably contributed to by microRNAs (miRNAs). Here, we used deep-sequencing, candidate-based expression studies and a selection of Lotus japonicus mutants uncoupling different symbiosis stages to identify miRNAs involved in symbiotic nitrogen fixation. Induction of a noncanonical miR171 isoform, which targets the key nodulation transcription factor Nodulation Signaling Pathway2, correlates with bacterial infection in nodules. A second candidate, miR397, is systemically induced in the presence of active, nitrogen-fixing nodules but not in that of noninfected or inactive nodule organs. It is involved in nitrogen fixation-related copper homeostasis and targets a member of the laccase copper protein family. These findings thus identify two miRNAs specifically responding to symbiotic infection and nodule function in legumes. PMID:23071252

  16. Ribotyping of rhizobia nodulating Acacia mangium and Paraserianthes falcataria from different geographical areas in Indonesia using PCR-RFLP-SSCP (PRS) and sequencing.

    PubMed

    Clapp, J P; Mansur, I; Dodd, J C; Jeffries, P

    2001-04-01

    Acacia mangium and Paraserianthes falcataria are leguminous tree species widely grown for timber in Indonesia and other tropical countries, yet little is known about the identity of their rhizobial symbionts. Polymerase chain reaction-restriction fragment length polymorphism-single-strand conformational polymorphism (PRS) analysis of the 16S rRNA gene was used along with sequencing to assess the diversity of 57 rhizobia isolated from nodules of A. mangium and P. falctaria in Indonesia. In total, 26 rhizobia isolated from A. mangium were analysed by PRS and sequencing. The PRS patterns indicated that 12 (46%) clustered with Bradyrhizobium elkanii, 13 (50%) with B. lianoningense/japonicum and one (4%) with Mesorhizobium loti. Thirty-one isolates were analysed from P. falcataria: five (16%) clustered with B. elkanii and 26 (84%) with B. lianoningense/japonicum. These results were confirmed by phylogenetic analysis of sequences. Intraspecific diversity of the 16S rRNA genes from rhizobia nodulating A. mangium and P. falcataria revealed by PRS was low, only one genotype was found within the isolates that clustered with B. elkanii and two within the B. liaoningense/japonicum group. These Bradyrhizobium species are apparently ubiquitous throughout the Indonesian archipelago and it is clear why the two tree species are able to successfully establish outside their native range without the need for inoculation with indigenous rhizobia. PMID:11359513

  17. Transcriptome Profiling of Lotus japonicus Roots During Arbuscular Mycorrhiza Development and Comparison with that of Nodulation

    PubMed Central

    Deguchi, Yuichi; Banba, Mari; Shimoda, Yoshikazu; Chechetka, Svetlana A.; Suzuri, Ryota; Okusako, Yasuhiro; Ooki, Yasuhiro; Toyokura, Koichi; Suzuki, Akihiro; Uchiumi, Toshiki; Higashi, Shiro; Abe, Mikiko; Kouchi, Hiroshi; Izui, Katsura; Hata, Shingo

    2007-01-01

    Abstract To better understand the molecular responses of plants to arbuscular mycorrhizal (AM) fungi, we analyzed the differential gene expression patterns of Lotus japonicus, a model legume, with the aid of a large-scale cDNA macroarray. Experiments were carried out considering the effects of contaminating microorganisms in the soil inoculants. When the colonization by AM fungi, i.e. Glomus mosseae and Gigaspora margarita, was well established, four cysteine protease genes were induced. In situ hybridization revealed that these cysteine protease genes were specifically expressed in arbuscule-containing inner cortical cells of AM roots. On the other hand, phenylpropanoid biosynthesis-related genes for phenylalanine ammonia-lyase (PAL), chalcone synthase, etc. were repressed in the later stage, although they were moderately up-regulated on the initial association with the AM fungus. Real-time RT–PCR experiments supported the array experiments. To further confirm the characteristic expression, a PAL promoter was fused with a reporter gene and introduced into L. japonicus, and then the transformants were grown with a commercial inoculum of G. mosseae. The reporter activity was augmented throughout the roots due to the presence of contaminating microorganisms in the inoculum. Interestingly, G. mosseae only colonized where the reporter activity was low. Comparison of the transcriptome profiles of AM roots and nitrogen-fixing root nodules formed with Mesorhizobium loti indicated that the PAL genes and other phenylpropanoid biosynthesis-related genes were similarly repressed in the two organs. PMID:17634281

  18. Nodulation of Sesbania Species by Rhizobium (Agrobacterium) Strain IRBG74 and Other Rhizobia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concatenated sequence analysis with 16S rRNA, rpoB and fusA genes identified a strain (IRBG74) isolated from root nodules of the aquatic legume Sesbania cannabina as a close relative of the plant pathogen Rhizobium radiobacter (syn. Agrobacterium tumefaciens). However, DNA:DNA hybridisation with R. ...

  19. Symbiotic effectiveness of antibiotic-resistant mutants of fast- and slow-growing strains of Rhizobium nodulating Lotus species.

    PubMed

    Pankhurst, C E

    1977-08-01

    Mutants resistant ot 16 individual antibiotics were isolated from two fast-growing and two slow-growing strains of Lotus rhizobia and their symbiotic effectiveness on Lotus pedunculatus evaluated. Resistance to streptomycin, spectinomycin, chloramphenicol, and tetracycline (inhibitors of protein synthesis) was associated with little or no loss of effectiveness with all four strains but resistance to nalidixic acid and rifampicin (inhibitors of nucleic acid synthesis), and to D-cycloserine, novobiocin, and penicillin (inhibitors of cell wall-cell membrane synthesis) was associated with significant loss of effectiveness in 20-100% of the mutants. Resistance to viomycin, neomycin, kanamycin, and vibramycin was associated with loss of effectiveness with mutants of the two fast-growing strains but not with mutants of the two slow-growing strains. When tested on four alternate host legumes individual mutants of a slow-growing strain showed significantly different levels of effectiveness. The results suggest that both the inherent characteristics of the bacterium and of the host plant will influence the symbiotic effectiveness of antibiotic-resistant mutants of Rhizobium. PMID:890601

  20. Genetic diversity of rhizobia isolated from nodules of the relic species Vavilovia formosa (Stev.) Fed.

    PubMed

    Safronova, Vera I; Kimeklis, Anastasiia K; Chizhevskaya, Elena P; Belimov, Andrey A; Andronov, Evgeny E; Pinaev, Alexander G; Pukhaev, Andrey R; Popov, Konstantin P; Tikhonovich, Igor A

    2014-02-01

    Sixteen bacterial strains were isolated from root nodules of Vavilovia formosa plants originated from the North Ossetian State Natural Reserve (Caucasus, Russia). Phylogenetic analysis of these strains was performed using partial 16S rRNA gene and internally transcribed spacer (ITS) sequences. The results showed that the isolates belong to three families of root nodule bacteria. Twelve of them were related to the genus Rhizobium (family Rhizobiaceae) but four strains can be most probably identified as Phyllobacterium-related (family Phyllobacteriaceae), Bosea- and Rhodopseudomonas-related (family Bradyrhizobiaceae). Amplified fragment length polymorphism clustering was congruent with ITS phylogeny but displayed more variability for Rhizobium isolates, which formed a single group at the level of 30 % similarity. We expect that the isolates obtained can belong to new taxa at genus, species or subspecies levels. The results of PCR amplification of the nodulation genes nodC and nodX showed their presence in all Rhizobium isolates and one Rhodopseudomonas-related isolate. The nodC gene sequences of V. formosa isolates were closely related to those of the species Rhizobium leguminosarum bv. viciae but formed separate clusters and did not intermingle with any reference strains. The presence of the nodX gene, which is necessary for nodulation of Afghan peas (Pisum sativum L.) originated from the Middle East, allows the speculation that these wild-type pea cultivars may be the closest existing relatives of V. formosa. Thus, the studies of genetic diversity and symbiotic genes of V. formosa microsymbionts provide the primary information about their phylogeny and contribute to the conservation of this relict leguminous species. PMID:24292378

  1. Construction of a Lotus japonicus late nodulin expressed sequence tag library and identification of novel nodule-specific genes.

    PubMed Central

    Szczyglowski, K; Hamburger, D; Kapranov, P; de Bruijn, F J

    1997-01-01

    A range of novel expressed sequence tags (ESTs) associated with late developmental events during nodule organogenesis in the legume Lotus japonicus were identified using mRNA differential display; 110 differentially displayed polymerase chain reaction products were cloned and analyzed. Of 88 unique cDNAs obtained, 22 shared significant homology to DNA/protein sequences in the respective databases. This group comprises, among others, a nodule-specific homolog of protein phosphatase 2C, a peptide transporter protein, and a nodule-specific form of cytochrome P450. RNA gel-blot analysis of 16 differentially displayed ESTs confirmed their nodule-specific expression pattern. The kinetics of mRNA accumulation of the majority of the ESTs analyzed were found to resemble the expression pattern observed for the L. japonicus leghemoglobin gene. These results indicate that the newly isolated molecular markers correspond to genes induced during late developmental stages of L. japonicus nodule organogenesis and provide important, novel tools for the study of nodulation. PMID:9276951

  2. Selection of alkalotolerant and symbiotically efficient chickpea nodulating rhizobia from North-West Indo Gangetic Plains.

    PubMed

    Singh, Raghvendra Pratap; Manchanda, Geetanjali; Singh, Ram Nageena; Srivastava, Alok Kumar; Dubey, R C

    2016-01-01

    In an effort to obtain reliable, alkali-tolerant, and symbiotically efficient rhizobial strains, 54 indigenous rhizobial isolates were obtained from root nodules of chickpea grown in alkaline soil of 5 different agricultural locations in North-West Indo Gangetic Plains (NW-IGP). Of these, 16 most symbiotically effective isolates were selected for polyphasic analysis (pH stress, salt tolerance, and genetic characterization). All the selected isolates were able to tolerate the high alkaline pH. Among them, CPN1, CPN8, and CPN32 grew well at pH 11.0. High pH-induced proteins were explored by SDS-PAGE assay. Identification and genetic characterization of isolates was done by 16S rRNA gene sequencing, RNA polymerase subunit-B (rpoB) and symbiotic genes (nodC and nifH). The study revealed diverse symbiotically efficient alkalotolerant chickpea nodulating rhizobial strains from NW-IGP. This study has thus contributed a valuable genetic pool of isolates that can potentially be used to increase chickpea production in these soil types. PMID:26377641

  3. NENA, a Lotus japonicus homolog of Sec13, is required for rhizodermal infection by arbuscular mycorrhiza fungi and rhizobia but dispensable for cortical endosymbiotic development.

    PubMed

    Groth, Martin; Takeda, Naoya; Perry, Jillian; Uchida, Hisaki; Dräxl, Stephan; Brachmann, Andreas; Sato, Shusei; Tabata, Satoshi; Kawaguchi, Masayoshi; Wang, Trevor L; Parniske, Martin

    2010-07-01

    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 encodes a WD40 repeat protein related to the nucleoporins Sec13 and Seh1. Localization of NENA to the nuclear rim and yeast two-hybrid experiments indicated a role for NENA in a conserved subcomplex of the nuclear pore scaffold. Although nena mutants were able to form pink nodules in symbiosis with Mesorhizobium loti, root hair infection was not observed. Moreover, Nod factor induction of the symbiotic genes NIN, SbtM4, and SbtS, as well as perinuclear calcium spiking, were impaired. Detailed phenotypic analyses of nena mutants revealed a rhizobial infection mode that overcame the lack of rhizodermal responsiveness and carried the hallmarks of crack entry, including a requirement for ethylene. CCaMK-dependent processes were only abolished in the rhizodermis but not in the cortex of nena mutants. These data support the concept of tissue-specific components for the activation of CCaMK. PMID:20675572

  4. Medicago truncatula Natural Resistance-Associated Macrophage Protein1 Is Required for Iron Uptake by Rhizobia-Infected Nodule Cells1[OPEN

    PubMed Central

    Tejada-Jiménez, Manuel; Castro-Rodríguez, Rosario; Kryvoruchko, Igor; Lucas, M. Mercedes; Udvardi, Michael; Imperial, Juan; González-Guerrero, Manuel

    2015-01-01

    Iron is critical for symbiotic nitrogen fixation (SNF) as a key component of multiple ferroproteins involved in this biological process. In the model legume Medicago truncatula, iron is delivered by the vasculature to the infection/maturation zone (zone II) of the nodule, where it is released to the apoplast. From there, plasma membrane iron transporters move it into rhizobia-containing cells, where iron is used as the cofactor of multiple plant and rhizobial proteins (e.g. plant leghemoglobin and bacterial nitrogenase). MtNramp1 (Medtr3g088460) is the M. truncatula Natural Resistance-Associated Macrophage Protein family member, with the highest expression levels in roots and nodules. Immunolocalization studies indicate that MtNramp1 is mainly targeted to the plasma membrane. A loss-of-function nramp1 mutant exhibited reduced growth compared with the wild type under symbiotic conditions, but not when fertilized with mineral nitrogen. Nitrogenase activity was low in the mutant, whereas exogenous iron and expression of wild-type MtNramp1 in mutant nodules increased nitrogen fixation to normal levels. These data are consistent with a model in which MtNramp1 is the main transporter responsible for apoplastic iron uptake by rhizobia-infected cells in zone II. PMID:25818701

  5. Rhizobia from Lanzarote, the Canary Islands, That Nodulate Phaseolus vulgaris Have Characteristics in Common with Sinorhizobium meliloti Isolates from Mainland Spain▿

    PubMed Central

    Zurdo-Piñeiro, José Luis; García-Fraile, Paula; Rivas, Raúl; Peix, Alvaro; León-Barrios, Milagros; Willems, Anne; Mateos, Pedro Francisco; Martínez-Molina, Eustoquio; Velázquez, Encarna; van Berkum, Peter

    2009-01-01

    The stable, low-molecular-weight (LMW) RNA fractions of several rhizobial isolates of Phaseolus vulgaris grown in the soil of Lanzarote, an island of the Canary Islands, were identical to a less-common pattern found within Sinorhizobium meliloti (assigned to group II) obtained from nodules of alfalfa and alfalfa-related legumes grown in northern Spain. The P. vulgaris isolates and the group II LMW RNA S. meliloti isolates also were distinguishable in that both had two conserved inserts of 20 and 46 bp in the 16S-23S internal transcribed spacer region that were not present in other strains of S. meliloti. The isolates from P. vulgaris nodulated bean but not Medicago sativa, while those recovered from Medicago, Melilotus, and Trigonella spp. nodulated both host legumes. The bean isolates also were distinguished from those of Medicago, Melilotus, and Trigonella spp. by nodC sequence analysis. The nodC sequences of the bean isolates were most similar to those reported for S. meliloti bv. mediterranense and Sinorhizobium fredii bv. mediterranense (GenBank accession numbers DQ333891 and AF217267, respectively). None of the evidence placed the bean isolates from Lanzarote in the genus Rhizobium, which perhaps is inconsistent with seed-borne transmission of Rhizobium etli from the Americas to the Canaries as an explanation for the presence of bean-nodulating rhizobia in soils of Lanzarote. PMID:19218416

  6. Phytohormone regulation of legume-rhizobia interactions.

    PubMed

    Ferguson, Brett J; Mathesius, Ulrike

    2014-07-01

    The symbiosis between legumes and nitrogen fixing bacteria called rhizobia leads to the formation of root nodules. Nodules are highly organized root organs that form in response to Nod factors produced by rhizobia, and they provide rhizobia with a specialized niche to optimize nutrient exchange and nitrogen fixation. Nodule development and invasion by rhizobia is locally controlled by feedback between rhizobia and the plant host. In addition, the total number of nodules on a root system is controlled by a systemic mechanism termed 'autoregulation of nodulation'. Both the local and the systemic control of nodulation are regulated by phytohormones. There are two mechanisms by which phytohormone signalling is altered during nodulation: through direct synthesis by rhizobia and through indirect manipulation of the phytohormone balance in the plant, triggered by bacterial Nod factors. Recent genetic and physiological evidence points to a crucial role of Nod factor-induced changes in the host phytohormone balance as a prerequisite for successful nodule formation. Phytohormones synthesized by rhizobia enhance symbiosis effectiveness but do not appear to be necessary for nodule formation. This review provides an overview of recent advances in our understanding of the roles and interactions of phytohormones and signalling peptides in the regulation of nodule infection, initiation, positioning, development, and autoregulation. Future challenges remain to unify hormone-related findings across different legumes and to test whether hormone perception, response, or transport differences among different legumes could explain the variety of nodules types and the predisposition for nodule formation in this plant family. In addition, the molecular studies carried out under controlled conditions will need to be extended into the field to test whether and how phytohormone contributions by host and rhizobial partners affect the long term fitness of the host and the survival and

  7. A Lotus japonicus Cochaperone Protein Interacts With the Ubiquitin-Like Domain Protein CIP73 and Plays a Negative Regulatory Role in Nodulation.

    PubMed

    Kang, Heng; Xiao, Aifang; Huang, Xiaoqin; Gao, Xioumei; Yu, Haixiang; He, Xingxing; Zhu, Hui; Hong, Zonglie; Zhang, Zhongming

    2015-05-01

    The calcium/calmodulin-dependent protein kinase CCaMK forms a complex with its phosphorylation target CIP73 (CCaMK-interacting protein of 73 kDa). In this work, a homolog of the animal HSC/HSP70 interacting protein (HIP) was identified as an interacting partner of CIP73 in Lotus japonicus. L. japonicus HIP contains all functional domains characteristic of animal HIP proteins. The C-terminal STI1-like domain of L. japonicus HIP was found to be necessary and sufficient for interaction with CIP73. The interaction between CIP73 and HIP occurred in both the nuclei and cytoplasm in Nicotiana benthamiana leaf cells. The interactions between CIP73 and HIP and between CIP73 and CCaMK could take place simultaneously in the same nuclei. HIP transcripts were detected in all plant tissues tested. As nodule primordia developed into young nodules, the expression of HIP was down-regulated and the HIP transcript level became very low in mature nodules. More nodules were formed in transgenic hairy roots of L. japonicus expressing HIP RNA interference at 16 days postinoculation as compared with the control hairy roots expressing the empty vector. It appears that HIP may play a role as a negative regulator for nodulation. PMID:25761207

  8. How legumes recognize rhizobia

    PubMed Central

    Via, Virginia Dalla; Zanetti, María Eugenia; Blanco, Flavio

    2016-01-01

    ABSTRACT Legume plants have developed the capacity to establish symbiotic interactions with soil bacteria (known as rhizobia) that can convert N2 to molecular forms that are incorporated into the plant metabolism. The first step of this relationship is the recognition of bacteria by the plant, which allows to distinguish potentially harmful species from symbiotic partners. The main molecular determinant of this symbiotic interaction is the Nod Factor, a diffusible lipochitooligosaccharide molecule produced by rhizobia and perceived by LysM receptor kinases; however, other important molecules involved in the specific recognition have emerged over the years. Secreted exopolysaccharides and the lipopolysaccharides present in the bacterial cell wall have been proposed to act as signaling molecules, triggering the expression of specific genes related to the symbiotic process. In this review we will briefly discuss how transcriptomic analysis are helping to understand how multiple signaling pathways, triggered by the perception of different molecules produced by rhizobia, control the genetic programs of root nodule organogenesis and bacterial infection. This knowledge can help to understand how legumes have evolved to recognize and establish complex ecological relationships with particular species and strains of rhizobia, adjusting gene expression in response to identity determinants of bacteria. PMID:26636731

  9. Overproduction of Indole-3-Acetic Acid in Free-Living Rhizobia Induces Transcriptional Changes Resembling Those Occurring in Nodule Bacteroids.

    PubMed

    Defez, Roberto; Esposito, Roberta; Angelini, Claudia; Bianco, Carmen

    2016-06-01

    Free-living bacteria grown under aerobic conditions were used to investigate, by next-generation RNA sequencing analysis, the transcriptional profiles of Sinorhizobium meliloti wild-type 1021 and its derivative, RD64, overproducing the main auxin indole-3-acetic acid (IAA). Among the upregulated genes in RD64 cells, we detected the main nitrogen-fixation regulator fixJ, the two intermediate regulators fixK and nifA, and several other genes known to be FixJ targets. The gene coding for the sigma factor RpoH1 and other genes involved in stress response, regulated in a RpoH1-dependent manner in S. meliloti, were also induced in RD64 cells. Under microaerobic condition, quantitative real-time polymerase chain reaction analysis revealed that the genes fixJL and nifA were up-regulated in RD64 cells as compared with 1021 cells. This work provided evidence that the overexpression of IAA in S. meliloti free-living cells induced many of the transcriptional changes that normally occur in nitrogen-fixing root nodule. PMID:27003799

  10. Hemoglobin LjGlb1-1 is involved in nodulation and regulates the level of nitric oxide in the Lotus japonicus–Mesorhizobium loti symbiosis

    PubMed Central

    Fukudome, Mitsutaka; Calvo-Begueria, Laura; Kado, Tomohiro; Osuki, Ken-ichi; Rubio, Maria Carmen; Murakami, Ei-ichi; Nagata, Maki; Kucho, Ken-ichi; Sandal, Niels; Stougaard, Jens; Becana, Manuel; Uchiumi, Toshiki

    2016-01-01

    Leghemoglobins transport and deliver O2 to the symbiosomes inside legume nodules and are essential for nitrogen fixation. However, the roles of other hemoglobins (Hbs) in the rhizobia–legume symbiosis are unclear. Several Lotus japonicus mutants affecting LjGlb1-1, a non-symbiotic class 1 Hb, have been used to study the function of this protein in symbiosis. Two TILLING alleles with single amino acid substitutions (A102V and E127K) and a LORE1 null allele with a retrotransposon insertion in the 5′-untranslated region (96642) were selected for phenotyping nodulation. Plants of all three mutant lines showed a decrease in long infection threads and nodules, and an increase in incipient infection threads. About 4h after inoculation, the roots of mutant plants exhibited a greater transient accumulation of nitric oxide (NO) than did the wild-type roots; nevertheless, in vitro NO dioxygenase activities of the wild-type, A102V, and E127K proteins were similar, suggesting that the mutated proteins are not fully functional in vivo. The expression of LjGlb1-1, but not of the other class 1 Hb of L. japonicus (LjGlb1-2), was affected during infection of wild-type roots, further supporting a specific role for LjGlb1-1. In conclusion, the LjGlb1-1 mutants reveal that this protein is required during rhizobial infection and regulates NO levels. PMID:27443280

  11. Rhizobia with different symbiotic efficiencies nodulate Acaciella angustissima in Mexico, including Sinorhizobium chiapanecum sp. nov. which has common symbiotic genes with Sinorhizobium mexicanum

    PubMed Central

    Rincón-Rosales, Reiner; Lloret, Lourdes; Ponce, Edith; Martínez-Romero, Esperanza

    2009-01-01

    Bacteria from nodules of the legume Acaciella angustissima native to the south of Mexico were characterized genetically and their nodulation and competitiveness were evaluated. Phylogenetic studies derived from rpoB gene sequences indicated that A. angustissima is nodulated by Sinorhizobium mexicanum, Rhizobium tropici, Mesorhizobium plurifarium and Agrobacterium tumefaciens and by bacteria related to Sinorhizobium americanum, Sinorhizobium terangae, Rhizobium etli and Rhizobium gallicum. A new lineage related to S. terangae is recognized based on the sequences of gyrA, nolR, recA, rpoB and rrs genes, DNA–DNA hybridization and phenotypic characteristics. The name for this new species is Sinorhizobium chiapanecum and its type strain is ITTG S70T. The symbiotic genes nodA and nifH were similar to those from S. mexicanum strains, which are Acaciella symbionts as well, with nodA gene sequences grouped within a cluster of nod genes from strains that nodulate plants from the Mimosoideae subfamily of the Leguminosae. Sinorhizobium isolates were the most frequently obtained from A. angustissima nodules and were among the best strains to promote plant growth in A. angustissima and to compete in interstrain nodule competition assays. Lateral transfer of symbiotic genes is not evident among the genera that nodulate A. angustissima (Rhizobium, Sinorhizobium and Mesorhizobium) but may occur among the sympatric and closely related sinorhizobia that nodulate Acaciella. PMID:19120461

  12. Characterization of the papilionoid-Burkholderia interaction in the Fynbos biome: The diversity and distribution of beta-rhizobia nodulating Podalyria calyptrata (Fabaceae, Podalyrieae).

    PubMed

    Lemaire, Benny; Van Cauwenberghe, Jannick; Verstraete, Brecht; Chimphango, Samson; Stirton, Charles; Honnay, Olivier; Smets, Erik; Sprent, Janet; James, Euan K; Muasya, A Muthama

    2016-02-01

    The South African Fynbos soils are renowned for nitrogen-fixing Burkholderia associated with diverse papilionoid legumes of the tribes Crotalarieae, Hypocalypteae, Indigofereae, Phaseoleae and Podalyrieae. However, despite numerous rhizobial studies in the region, the symbiotic diversity of Burkholderia has not been investigated in relation to a specific host legume and its geographical provenance. This study analyzed the diversity of nodulating strains of Burkholderia from the legume species Podalyria calyptrata. Diverse lineages were detected that proved to be closely related to Burkholderia taxa, originating from hosts in other legume tribes. By analyzing the genetic variation of chromosomal (recA) and nodulation (nodA) sequence data in relation to the sampling sites we assessed the geographical distribution patterns of the P. calyptrata symbionts. Although we found a degree of genetically differentiated rhizobial populations, a correlation between genetic (recA and nodA) and geographic distances among populations was not observed, suggesting high rates of dispersal and rhizobial colonization within Fynbos soils. PMID:26689612

  13. The abundance and diversity of legume-nodulating rhizobia in 28-year-old plantations of tropical, subtropical, and exotic tree species: a case study from the Forest Reserve of Bandia, Senegal.

    PubMed

    Sene, Godar; Thiao, Mansour; Samba-Mbaye, Ramatoulaye; Khasa, Damase; Kane, Aboubacry; Mbaye, Mame Samba; Beaulieu, Marie-Ève; Manga, Anicet; Sylla, Samba Ndao

    2013-01-01

    Several fast-growing and multipurpose tree species have been widely used in West Africa to both reverse the tendency of land degradation and restore soil productivity. Although beneficial effects have been reported on soil stabilization, there still remains a lack of information about their impact on soil microorganisms. Our investigation has been carried out in exotic and native tree plantations of 28 years and aimed to survey and compare the abundance and genetic diversity of natural legume-nodulating rhizobia (LNR). The study of LNR is supported by the phylogenetic analysis which clustered the isolates into three genera: Bradyrhizobium, Mesorhizobium, and Sinorhizobium. The results showed close positive correlations between the sizes of LNR populations estimated both in the dry and rainy seasons and the presence of legume tree hosts. There were significant increases in Rhizobium spp. population densities in response to planting with Acacia spp., and high genetic diversities and richness of genotypes were fittest in these tree plantations. This suggests that enrichment of soil Rhizobium spp. populations is host specific. The results indicated also that species of genera Mesorhizobium and Sinorhizobium were lacking in plantations of non-host species. By contrast, there was a widespread distribution of Bradyrhizobium spp. strains across the tree plantations, with no evident specialization in regard to plantation type. Finally, the study provides information about the LNR communities associated with a range of old tree plantations and some aspects of their relationships to soil factors, which may facilitate the management of man-made forest systems that target ecosystem rehabilitation and preservation of soil biota. PMID:22864803

  14. Bosea vaviloviae sp. nov., a new species of slow-growing rhizobia isolated from nodules of the relict species Vavilovia formosa (Stev.) Fed.

    PubMed

    Safronova, Vera I; Kuznetsova, Irina G; Sazanova, Anna L; Kimeklis, Anastasiia K; Belimov, Andrey A; Andronov, Evgeny E; Pinaev, Alexander G; Chizhevskaya, Elena P; Pukhaev, Andrey R; Popov, Konstantin P; Willems, Anne; Tikhonovich, Igor A

    2015-04-01

    The Gram-negative, rod-shaped slow-growing strains Vaf-17, Vaf-18(T) and Vaf-43 were isolated from the nodules of Vavilovia formosa plants growing in the hard-to-reach mountainous region of the North Ossetian State Natural Reserve (north Caucasus, Russian Federation). The sequencing of 16S rDNA (rrs), ITS region and five housekeeping genes (atpD, dnaK, recA, gyrB and rpoB) showed that the isolated strains were most closely related to the species Bosea lathyri (class Alphaproteobacteria, family Bradyrhizobiaceae) which was described for isolates from root nodules of Lathyrus latifolius. However the sequence similarity between the isolated strains and the type strain B. lathyri LMG 26379(T) for the ITS region was 90 % and for the housekeeping genes it was ranged from 92 to 95 %. All phylogenetic trees, except for the rrs-dendrogram showed that the isolates from V. formosa formed well-separated clusters within the Bosea group. Differences in phenotypic properties of the B. lathyri type strain and the isolates from V. formosa were studied using the microassay system GENIII MicroPlate BioLog. Whole-cell fatty acid analysis showed that the strains Vaf-17, Vaf-18(T) and Vaf-43 had notable amounts of C16:0 (4.8-6.0 %), C16:0 3-OH (6.4-6.6 %), C16:1 ω5c (8.8-9.0 %), C17:0 cyclo (13.5-13.9 %), C18:1 ω7c (43.4-45.4 %), C19:0 cyclo ω8c (10.5-12.6 %) and Summed Feature (SF) 3 (6.4-8.0 %). The DNA-DNA relatedness between the strains Vaf-18(T) and B. lathyri LMG 26379(T) was 24.0 %. On the basis of genotypic and phenotypic analysis a new species Bosea vaviloviae sp. nov. (type strain RCAM 02129(T) = LMG 28367(T) = Vaf-18(T)) is proposed. PMID:25603982

  15. Secretion systems and signal exchange between nitrogen-fixing rhizobia and legumes

    PubMed Central

    Nelson, Matthew S.; Sadowsky, Michael J.

    2015-01-01

    The formation of symbiotic nitrogen-fixing nodules on the roots and/or stem of leguminous plants involves a complex signal exchange between both partners. Since many microorganisms are present in the soil, legumes and rhizobia must recognize and initiate communication with each other to establish symbioses. This results in the formation of nodules. Rhizobia within nodules exchange fixed nitrogen for carbon from the legume. Symbiotic relationships can become non-beneficial if one partner ceases to provide support to the other. As a result, complex signal exchange mechanisms have evolved to ensure continued, beneficial symbioses. Proper recognition and signal exchange is also the basis for host specificity. Nodule formation always provides a fitness benefit to rhizobia, but does not always provide a fitness benefit to legumes. Therefore, legumes have evolved a mechanism to regulate the number of nodules that are formed, this is called autoregulation of nodulation. Sequencing of many different rhizobia have revealed the presence of several secretion systems - and the Type III, Type IV, and Type VI secretion systems are known to be used by pathogens to transport effector proteins. These secretion systems are also known to have an effect on host specificity and are a determinant of overall nodule number on legumes. This review focuses on signal exchange between rhizobia and legumes, particularly focusing on the role of secretion systems involved in nodule formation and host specificity. PMID:26191069

  16. Molecular diversity of native rhizobia trapped by five field pea genotypes in Indian soils.

    PubMed

    Wadhwa, K; Dudeja, S S; Yadav, R K

    2011-02-01

    Five pea cultivars; HFP 4, HVP 3-5, HFP 9426, Jayanti and Hariyal, being grown in CCS Haryana Agricultural University farm were used to isolate native rhizobia. Selected 54 rhizobia, from all cultivars, were authenticated as rhizobia by plant infectivity test. Along with nodulation, symbiotic effectiveness in terms of symbiotic ratios showed wide range of effectiveness of pea rhizobia from 1.11 to 5.0. DNA of all the 54 rhizobia was extracted and amplified by PCR, using ERIC and 16S rDNA primers. Dendrogram based on ERIC profiles of these 54 rhizobia showed the formation of 13 subclusters at 80% level of similarity. Dendrogram based on RFLP of 16S rDNA by three restriction endonucleases; Msp I, Csp 6I and Rsa I; also formed 13 subclusters at 80% level of similarity. However, positioning of subclusters was different from that of ERIC based dendrogram. Majority of the isolates i.e. 64.8% by ERIC profiles and 44.4% by RFLP of 16S rDNA formed one cluster. Isolates from same nodule were not 100% similar. Considering each cluster representing a rhizobial genotype, both techniques used to assess molecular diversity indicated the presence of 13 genotypes of field pea rhizobia in CCS Haryana Agricultural University farm soil. Two pea rhizobial genotypes were able to nodulate all the five pea cultivars. Furthermore, high strain richness index (0.43-0.5) of field pea rhizobia was observed by both the techniques. PMID:20806252

  17. Increased accumulation of trehalose in rhizobia cultured under 1% oxygen

    SciTech Connect

    Hoelzle, I.; Streeter, J.G. )

    1990-10-01

    The growth of rhizobia under 1% O{sub 2} induced the accumulation of {alpha},{alpha}-trehalose, and the effect of low O{sub 2} was independent of medium composition and Rhizobium species. Trehalose concentration in cells declined rapidly when microaerobic cultures were supplied with 21% O{sub 2}. Trehalose formation in nodules may be induced by the microaerobic environment.

  18. The Ribosomal RNA is a Useful Marker to Visualize Rhizobia Interacting with Legume Plants

    ERIC Educational Resources Information Center

    Rinaudi, Luciana; Isola, Maria C.; Giordano, Walter

    2004-01-01

    Symbiosis between rhizobia and leguminous plants leads to the formation of nitrogen-fixing root nodules. In the present article, we recommend the use of the ribosomal RNA (rRNA) isolated from legume nodules in an experimental class with the purpose of introducing students to the structure of eukaryotic and prokaryotic ribosomes and of…

  19. Sanctions and mutualism stability: why do rhizobia fix nitrogen?

    PubMed Central

    West, Stuart A; Kiers, E Toby; Simms, Ellen L; Denison, R Ford

    2002-01-01

    Why do rhizobia expend resources on fixing N(2) for the benefit of their host plant, when they could use those resources for their own reproduction? We present a series of theoretical models which counter the hypotheses that N(2) fixation is favoured because it (i) increases the exudation of useful resources to related rhizobia in the nearby soil, or (ii) increases plant growth and therefore the resources available for rhizobia growth. Instead, we suggest that appreciable levels of N(2) fixation are only favoured when plants preferentially supply more resources to (or are less likely to senesce) nodules that are fixing more N(2) (termed plant sanctions). The implications for different agricultural practices and mutualism stability in general are discussed. PMID:11934359

  20. Rhizobia from Lanzarote, the Canary Islands, that nodulate Phaseolus vulgaris have characteristics in common with LMW RNA group II Sinorhizobium meliloti of Medicago, Melilotus and Trigonella from soils of mainland Spain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several isolates from nodules of Phaseolus vulgaris grown in soil of Lanzarote, an island of the Canaries, had electrophoretic LMW RNA patterns identical with a less common pattern within S. meliloti (assigned as group II) obtained from nodules of alfalfa and alfalfa-related legumes grown in northe...

  1. Direct and interactive effects of light and nutrients on the legume-rhizobia mutualism

    NASA Astrophysics Data System (ADS)

    Lau, Jennifer A.; Bowling, Evan James; Gentry, Lowell E.; Glasser, Paul A.; Monarch, Elizabeth A.; Olesen, Whitney M.; Waxmonsky, Jillian; Young, Ryan Thomas

    2012-02-01

    The relative abundance of traded resources can alter the outcomes of symbioses, potentially shifting mutually-beneficial interactions into interactions that are detrimental to one or both partners. We manipulated the legume-rhizobia symbiosis and light and nutrient levels to investigate how the net growth benefits to both partners shift across environments differing in the availability of both traded resources. In low nutrient, high light environments, rhizobia increased mean plant biomass by 62%. In contrast, when plants were light-limited, rhizobia did not increase above-ground biomass and reduced mean below-ground biomass by 46%. Similarly, rhizobia only increased plant biomass under low nutrient conditions. Resource availability also affected nodule traits correlated with rhizobia fitness, with light-limited plants producing fewer and smaller nodules. Our results suggest that the growth benefits to both partners in the legume-rhizobia symbiosis depend on the availability of both traded resources. We also detected evidence, however, that plants may reduce investment in symbionts as the net benefits of association decrease, potentially limiting how far this interaction shifts toward parasitism in low-light, high nutrient environments.

  2. Estimating Divergence Times and Substitution Rates in Rhizobia.

    PubMed

    Chriki-Adeeb, Rim; Chriki, Ali

    2016-01-01

    Accurate estimation of divergence times of soil bacteria that form nitrogen-fixing associations with most leguminous plants is challenging because of a limited fossil record and complexities associated with molecular clocks and phylogenetic diversity of root nodule bacteria, collectively called rhizobia. To overcome the lack of fossil record in bacteria, divergence times of host legumes were used to calibrate molecular clocks and perform phylogenetic analyses in rhizobia. The 16S rRNA gene and intergenic spacer region remain among the favored molecular markers to reconstruct the timescale of rhizobia. We evaluate the performance of the random local clock model and the classical uncorrelated lognormal relaxed clock model, in combination with four tree models (coalescent constant size, birth-death, birth-death incomplete sampling, and Yule processes) on rhizobial divergence time estimates. Bayes factor tests based on the marginal likelihoods estimated from the stepping-stone sampling analyses strongly favored the random local clock model in combination with Yule process. Our results on the divergence time estimation from 16S rRNA gene and intergenic spacer region sequences are compatible with age estimates based on the conserved core genes but significantly older than those obtained from symbiotic genes, such as nodIJ genes. This difference may be due to the accelerated evolutionary rates of symbiotic genes compared to those of other genomic regions not directly implicated in nodulation processes. PMID:27168719

  3. Estimating Divergence Times and Substitution Rates in Rhizobia

    PubMed Central

    Chriki-Adeeb, Rim; Chriki, Ali

    2016-01-01

    Accurate estimation of divergence times of soil bacteria that form nitrogen-fixing associations with most leguminous plants is challenging because of a limited fossil record and complexities associated with molecular clocks and phylogenetic diversity of root nodule bacteria, collectively called rhizobia. To overcome the lack of fossil record in bacteria, divergence times of host legumes were used to calibrate molecular clocks and perform phylogenetic analyses in rhizobia. The 16S rRNA gene and intergenic spacer region remain among the favored molecular markers to reconstruct the timescale of rhizobia. We evaluate the performance of the random local clock model and the classical uncorrelated lognormal relaxed clock model, in combination with four tree models (coalescent constant size, birth–death, birth–death incomplete sampling, and Yule processes) on rhizobial divergence time estimates. Bayes factor tests based on the marginal likelihoods estimated from the stepping-stone sampling analyses strongly favored the random local clock model in combination with Yule process. Our results on the divergence time estimation from 16S rRNA gene and intergenic spacer region sequences are compatible with age estimates based on the conserved core genes but significantly older than those obtained from symbiotic genes, such as nodIJ genes. This difference may be due to the accelerated evolutionary rates of symbiotic genes compared to those of other genomic regions not directly implicated in nodulation processes. PMID:27168719

  4. Cloning of nod gene regions from mesquite rhizobia and bradyrhizobia and nucleotide sequence of the nodD gene from mesquite rhizobia.

    PubMed Central

    Thomas, P M; Golly, K F; Virginia, R A; Zyskind, J W

    1995-01-01

    Nitrogen-fixing symbiosis between bacteria and the tree legume mesquite (Prosopis glandulosa) is important for the maintenance of many desert ecosystems. Genes essential for nodulation and for extending the host range to mesquite were isolated from cosmid libraries of Rhizobium (mesquite) sp. strain HW17b and Bradyrhizobium (mesquite) sp. strain HW10h and were shown to be closely linked. All of the cosmid clones of rhizobia that extended the host range of Rhizobium (Parasponia) sp. strain NGR234CS to mesquite also supported nodulation of a Sym- mesquite strain. The cosmid clones of bradyrhizobia that extended the host range of Rhizobium (Parasponia) sp. strain NGR234CS to mesquite were only able to confer nodulation ability in the Sym- mesquite strain if they also contained a nodD-hybridizing region. Subclones containing just the nodD genes of either genus did not extend the host range of Rhizobium (Parasponia) sp. to mesquite, indicating that the nodD gene is insufficient for mesquite nodulation. The nodD gene region is conserved among mesquite-nodulating rhizobia regardless of the soil depth from which they were collected, indicating descent from a common ancestor. In a tree of distance relationships, the NodD amino acid sequence from mesquite rhizobia clusters with homologs from symbionts that can infect both herbaceous and tree legumes, including Rhizobium tropici, Rhizobium leguminosarum bv; phaseoli, Rhizobium loti, and Bradyrhizobium japonicum. PMID:7574650

  5. Cloning of nod gene regions from mesquite rhizobia and bradyrhizobia and nucleotide sequence of the nodD gene from mesquite rhizobia.

    PubMed

    Thomas, P M; Golly, K F; Virginia, R A; Zyskind, J W

    1995-09-01

    Nitrogen-fixing symbiosis between bacteria and the tree legume mesquite (Prosopis glandulosa) is important for the maintenance of many desert ecosystems. Genes essential for nodulation and for extending the host range to mesquite were isolated from cosmid libraries of Rhizobium (mesquite) sp. strain HW17b and Bradyrhizobium (mesquite) sp. strain HW10h and were shown to be closely linked. All of the cosmid clones of rhizobia that extended the host range of Rhizobium (Parasponia) sp. strain NGR234CS to mesquite also supported nodulation of a Sym- mesquite strain. The cosmid clones of bradyrhizobia that extended the host range of Rhizobium (Parasponia) sp. strain NGR234CS to mesquite were only able to confer nodulation ability in the Sym- mesquite strain if they also contained a nodD-hybridizing region. Subclones containing just the nodD genes of either genus did not extend the host range of Rhizobium (Parasponia) sp. to mesquite, indicating that the nodD gene is insufficient for mesquite nodulation. The nodD gene region is conserved among mesquite-nodulating rhizobia regardless of the soil depth from which they were collected, indicating descent from a common ancestor. In a tree of distance relationships, the NodD amino acid sequence from mesquite rhizobia clusters with homologs from symbionts that can infect both herbaceous and tree legumes, including Rhizobium tropici, Rhizobium leguminosarum bv; phaseoli, Rhizobium loti, and Bradyrhizobium japonicum. PMID:7574650

  6. R gene-controlled host specificity in the legume-rhizobia symbiosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. Here we report the...

  7. Diversity and symbiotic effectiveness of beta-rhizobia isolated from sub-tropical legumes of a Brazilian Araucaria Forest.

    PubMed

    Lammel, Daniel R; Cruz, Leonardo M; Carrer, Helaine; Cardoso, Elke J B N

    2013-12-01

    While the occurrence of Betaproteobacteria occupying the nodules of tropical legumes has been shown, little is known about subtropical areas. Araucaria Forest is a subtropical endangered ecosystem, and a better understanding of the legume-rhizobial symbionts may allow their use in land reclamation. The 16S rRNA gene of bacteria isolated from nine leguminous species was sequenced and their nodulation tested in Mimosa scabrella and Phaseolus vulgaris. 196 isolates were identified as eight genotypes: Pantoea, Pseudomonas, Bradyrhizobium sp1-2, Rhizobium, and Burkholderia sp1-3. The majority of the isolates from native plants (87 %) were taxonomically related to β-rhizobia, namely Burkholderia, however the legumes Galactia crassifolia and Collea speciosa were nodulated by both α and β-rhizobia, and Acacia dealbata, an exotic plant, only by α-rhizobia. The nifH genes of some isolates were sequenced and N-fixing potential shown by the acetylene reduction test. Most of the isolates nodulated the test plants, some were effective in M. scabrella, but all presented low efficiency in the exotic promiscuous legume P. vulgaris. Pantoea and Pseudomonas did not nodulate and probably are endophytic bacteria. The presented data shows diversity of α, β and γ-Proteobacteria in nodules of subtropical legumes, and suggests host specificity with β-rhizobia. Potential isolates were found for M. scabrella, indicating that a high N-fixing strain may be further inoculated in plants for use in reforestation. PMID:23861038

  8. Characterization of indigenous rhizobia from caatinga

    PubMed Central

    Pires e Teixeira, Fernanda Cíntia; Borges, Wardsson Lustrino; Xavier, Gustavo Ribeiro; Rumjanek, Norma Gouvêa

    2010-01-01

    The aim of this study was to characterize rhizobial isolates from Cratylia mollis Mart. ex Benth, Calliandra depauperata Benth. and Mimosa tenuiflora (Willd.) Poir. by means of rhizobial colonies morphology and restriction analysis of the 16S ribosomal gene (16S rDNA-ARDRA). Nodules were collected in the field and from plants cultivated in a greenhouse experiment using Caatinga soil samples. Sixty seven isolates were described by morphological analysis. Forty seven representative isolates were used for ARDRA analysis using seven restriction enzymes. We observed high diversity of both slow and fast-growing rhizobia that formed three morpho-physiological clusters. A few fast-growing isolates formed a group of strains of the Bradyrhizobium type; however, most of them diverged from the B. japonicum and B. elkanii species. Cratylia mollis nodule isolates were the most diverse, while all Mimosa tenuiflora isolates displayed fast growth with no pH change and were clustered into groups bearing 100% similarity, according to ARDRA results. PMID:24031482

  9. Characterization of indigenous rhizobia from caatinga.

    PubMed

    Pires E Teixeira, Fernanda Cíntia; Borges, Wardsson Lustrino; Xavier, Gustavo Ribeiro; Rumjanek, Norma Gouvêa

    2010-01-01

    The aim of this study was to characterize rhizobial isolates from Cratylia mollis Mart. ex Benth, Calliandra depauperata Benth. and Mimosa tenuiflora (Willd.) Poir. by means of rhizobial colonies morphology and restriction analysis of the 16S ribosomal gene (16S rDNA-ARDRA). Nodules were collected in the field and from plants cultivated in a greenhouse experiment using Caatinga soil samples. Sixty seven isolates were described by morphological analysis. Forty seven representative isolates were used for ARDRA analysis using seven restriction enzymes. We observed high diversity of both slow and fast-growing rhizobia that formed three morpho-physiological clusters. A few fast-growing isolates formed a group of strains of the Bradyrhizobium type; however, most of them diverged from the B. japonicum and B. elkanii species. Cratylia mollis nodule isolates were the most diverse, while all Mimosa tenuiflora isolates displayed fast growth with no pH change and were clustered into groups bearing 100% similarity, according to ARDRA results. PMID:24031482

  10. [Genetic diversity of rhizobia isolated from common legumes in the Karst area. Northwest Guangxi].

    PubMed

    Liu, Lu; He, Xun-yang; Xie, Qiang; Wang, Ke-lin

    2015-12-01

    Legumes, with a strong resistance to the adverse environmental conditions, are pioneer plants in degraded habitats, and play an important role in ecosystem restoration. In this study, the nodulation characteristics of 24 legumes were surveyed in the Karst area of Northwest Guangxi. A total of 39 nodule samples were collected from 15 legumes, the DNA was extracted and the 16S rDNA and nifH gene were amplified. A phylogenetic tree was then constructed to analyze the genetic diversity of rhizobia. The results showed that 15 legumes were nodulated, of which 14 belonged to the Papilionoideae, one to the Mimosaceae, and none to the Caesalpinoideae. No nodules were found on some legumes that were reported as nodulated, which might result from soil water stress in Karst. BLAST result and phylogenetic analyse indicated that most of the legumes were associated with rhizobia that belonged to the genus Bradyrhizobium, with the exception of two samples from Callerya nitida that were associated with the genus Mesorhizobium. In the phylogenetic tree, the sequences obtained from the same plot or the sequences from the same host species clustered together in most cases. This finding suggested that host selection and the ecological environment are the major factors that influence the genotype of rhizobia. PMID:27112003

  11. The effect of acidity on the distribution and symbiotic efficiency of rhizobia in Lithuanian soils

    NASA Astrophysics Data System (ADS)

    Lapinskas, E. B.

    2007-04-01

    The distribution and symbiotic efficiency of nodule bacteria Rhizobium leguminosarum_bv. trifolii F., Sinorhizobium meliloti D., Rhizobium galegae L., and Rhizobium leguminosarum bv. viciae F. in Lithuanian soils as dependent on the soil acidity were studied in the long-term field, pot, and laboratory experiments. The critical and optimal pH values controlling the distribution of rhizobia and the symbiotic nitrogen fixation were determined for every bacterial species. The relationship was found between the soil pH and the nitrogen-fixing capacity of rhizobia. A positive effect of liming of acid soils in combination with inoculation of legumes on the efficiency of symbiotic nitrogen fixation was demonstrated.

  12. Phylogeny of Symbiotic Genes and the Symbiotic Properties of Rhizobia Specific to Astragalus glycyphyllos L.

    PubMed Central

    Gnat, Sebastian; Małek, Wanda; Oleńska, Ewa; Wdowiak-Wróbel, Sylwia; Kalita, Michał; Łotocka, Barbara; Wójcik, Magdalena

    2015-01-01

    The phylogeny of symbiotic genes of Astragalus glycyphyllos L. (liquorice milkvetch) nodule isolates was studied by comparative sequence analysis of nodA, nodC, nodH and nifH loci. In all these genes phylograms, liquorice milkvetch rhizobia (closely related to bacteria of three species, i.e. Mesorhizobium amorphae, Mesorhizobium septentrionale and Mesorhizobium ciceri) formed one clearly separate cluster suggesting the horizontal transfer of symbiotic genes from a single ancestor to the bacteria being studied. The high sequence similarity of the symbiotic genes of A. glycyphyllos rhizobia (99–100% in the case of nodAC and nifH genes, and 98–99% in the case of nodH one) points to the relatively recent (in evolutionary scale) lateral transfer of these genes. In the nodACH and nifH phylograms, A. glycyphyllos nodule isolates were grouped together with the genus Mesorhizobium species in one monophyletic clade, close to M. ciceri, Mesorhizobium opportunistum and Mesorhizobium australicum symbiovar biserrulae bacteria, which correlates with the close relationship of these rhizobia host plants. Plant tests revealed the narrow host range of A. glycyphyllos rhizobia. They formed effective symbiotic interactions with their native host (A. glycyphyllos) and Amorpha fruticosa but not with 11 other fabacean species. The nodules induced on A. glycyphyllos roots were indeterminate with apical, persistent meristem, an age gradient of nodule tissues and cortical vascular bundles. To reflect the symbiosis-adaptive phenotype of rhizobia, specific for A. glycyphyllos, we propose for these bacteria the new symbiovar “glycyphyllae”, based on nodA and nodC genes sequences. PMID:26496493

  13. Phylogenetic Diversity of Ammopiptanthus Rhizobia and Distribution of Rhizobia Associated with Ammopiptanthus mongolicus in Diverse Regions of Northwest China.

    PubMed

    Zhao, Liang; Wang, Xinye; Huo, Haibo; Yuan, Guiji; Sun, Yali; Zhang, Dehui; Cao, Ying; Xu, Lin; Wei, Gehong

    2016-07-01

    Aiming to investigate the diversity and distribution of rhizobia associated with Ammopiptanthus, an endangered evergreen legume widely distributed in deserts, we characterized a total of 219 nodule isolates from nine sampling sites in Northwest China with different soil characteristics based upon restriction fragment length polymorphism (RFLP) analysis of 16S ribosomal RNA (rRNA) and symbiotic genes (nodC and nifH). Ten isolates representing different 16S rRNA-RFLP types were selected for further sequence analyses of 16S rRNA and four housekeeping genes. As results, nine genospecies belonging to the genera Ensifer, Neorhizobium, Agrobacterium, Pararhizobium, and Rhizobium could be defined among the isolates. The nodC and nifH phylogenies of 14 isolates representing different symbiotic-RFLP types revealed five lineages linked to Ensifer fredii, Ensifer meliloti, Rhizobium leguminosarum, Mesorhizobium amorphae, and Rhizobium gallicum, which demonstrated the various origins and lateral transfers of symbiotic genes between different genera and species. The rhizobial diversities of Ammopiptanthus mongolicus varied among regions, and the community compositions of rhizobia associated with A. mongolicus were significantly different in wild and cultured fields. Constrained correspondence analysis showed that the distribution of A. mongolicus rhizobia could be explained by available potassium content and that the assembly of symbiotic types was mainly affected by available phosphorus content and carbon-nitrogen ratio. PMID:27079453

  14. Ethiopian soils harbor natural populations of rhizobia that form symbioses with common bean ( Phaseolus vulgaris L.).

    PubMed

    Beyene, Desta; Kassa, Serawit; Ampy, Franklin; Asseffa, Amha; Gebremedhin, Tadesse; van Berkum, Peter

    2004-02-01

    The diversity and taxonomic relationships of 83 bean-nodulating rhizobia indigenous to Ethiopian soils were characterized by PCR-RFLP of the internally transcribed spacer (ITS) region between the 16S and 23S rRNA genes, 16S rRNA gene sequence analysis, multilocus enzyme electrophoresis (MLEE), and amplified fragment-length polymorphism. The isolates fell into 13 distinct genotypes according to PCR-RFLP analysis of the ITS region. Based on MLEE, the majority of these genotypes (70%) was genetically related to the type strain of Rhizobium leguminosarum. However, from analysis of their 16S rRNA genes, the majority was placed with Rhizobium etli. Transfer and recombination of the 16S rRNA gene from presumptively introduced R. etli to local R. leguminosarum is a possible theory to explain these contrasting results. However, it seems unlikely that bean rhizobia originating from the Americas (or Europe) extensively colonized soils of Ethiopia because Rhizobium tropici, Rhizobium gallicum, and Rhizobium giardinii were not detected and only a single ineffective isolate of R. etli that originated from a remote location was identified. Therefore, Ethiopian R. leguminosarum may have acquired the determinants for nodulation of bean from a low number of introduced bean-nodulating rhizobia that either are poor competitors for nodulation of bean or that failed to survive in the Ethiopian environment. Furthermore, it may be concluded from the genetic data presented here that the evidence for separating R. leguminosarum and R. etli into two separate species is inconclusive. PMID:14685648

  15. Coordinating nodule morphogenesis with rhizobial infection in legumes.

    PubMed

    Oldroyd, Giles E D; Downie, J Allan

    2008-01-01

    The formation of nitrogen-fixing nodules on legumes requires an integration of infection by rhizobia at the root epidermis and the initiation of cell division in the cortex, several cell layers away from the sites of infection. Several recent developments have added to our understanding of the signaling events in the epidermis associated with the perception of rhizobial nodulation factors and the role of plant hormones in the activation of cell division leading to nodule morphogenesis. This review focuses on the tissue-specific nature of the developmental processes associated with nodulation and the mechanisms by which these processes are coordinated during the formation of a nodule. PMID:18444906

  16. Genetic Diversity and Symbiotic Phenotype of Hairy Vetch Rhizobia in Japan.

    PubMed

    Yuan, Kun; Miwa, Hiroki; Iizuka, Maki; Yokoyama, Tadashi; Fujii, Yoshiharu; Okazaki, Shin

    2016-06-25

    Hairy vetch (Vicia villosa Roth) is a leguminous crop widely used as green manure and a cover crop in Japan. It exhibits strong weed-suppressing activity, high resistance to insect pests, and the ability to fix nitrogen through symbiotic interactions with soil bacteria known as rhizobia. Few studies have investigated the rhizobia that form nodules on hairy vetch in Japan, and the biological resources available for selecting high nitrogen-fixing rhizobia are limited. In the present study, we isolated 110 hairy vetch rhizobia from 13 different areas in Japan. Based on their 16S rRNA gene sequences, 73% of the isolates were identified as Rhizobium leguminosarum. A comparative analysis of nodC and 16S rRNA gene phylogenies revealed that several isolates possessed congruent nodC sequences despite having divergent 16S rRNA gene sequences, suggesting that the horizontal transfer of nod genes occurred during the evolution of rhizobia. Inoculation tests showed that isolates closely related to R. leguminosarum had better plant growth-promoting effects than other strains, thereby providing a promising agricultural resource for inoculating crops. PMID:27151657

  17. Genetic Diversity and Symbiotic Phenotype of Hairy Vetch Rhizobia in Japan

    PubMed Central

    Yuan, Kun; Miwa, Hiroki; Iizuka, Maki; Yokoyama, Tadashi; Fujii, Yoshiharu; Okazaki, Shin

    2016-01-01

    Hairy vetch (Vicia villosa Roth) is a leguminous crop widely used as green manure and a cover crop in Japan. It exhibits strong weed-suppressing activity, high resistance to insect pests, and the ability to fix nitrogen through symbiotic interactions with soil bacteria known as rhizobia. Few studies have investigated the rhizobia that form nodules on hairy vetch in Japan, and the biological resources available for selecting high nitrogen-fixing rhizobia are limited. In the present study, we isolated 110 hairy vetch rhizobia from 13 different areas in Japan. Based on their 16S rRNA gene sequences, 73% of the isolates were identified as Rhizobium leguminosarum. A comparative analysis of nodC and 16S rRNA gene phylogenies revealed that several isolates possessed congruent nodC sequences despite having divergent 16S rRNA gene sequences, suggesting that the horizontal transfer of nod genes occurred during the evolution of rhizobia. Inoculation tests showed that isolates closely related to R. leguminosarum had better plant growth-promoting effects than other strains, thereby providing a promising agricultural resource for inoculating crops. PMID:27151657

  18. Plant Dependence on Rhizobia for Nitrogen Influences Induced Plant Defenses and Herbivore Performance

    PubMed Central

    Dean, Jennifer M.; Mescher, Mark C.; De Moraes, Consuelo M.

    2014-01-01

    Symbiotic rhizobia induce many changes in legumes that could affect aboveground interactions with herbivores. We explored how changing the intensity of Bradyrhizobium japonicum, as modulated by soil nitrogen (N) levels, influenced the interaction between soybean (Glycine max) and herbivores of different feeding guilds. When we employed a range of fertilizer applications to manipulate soil N, plants primarily dependent on rhizobia for N exhibited increased root nodulation and higher levels of foliar ureides than plants given N fertilizer; yet all treatments maintained similar total N levels. Soybean podworm (Helicoverpa zea) larvae grew best on plants with the highest levels of rhizobia but, somewhat surprisingly, preferred to feed on high-N-fertilized plants when given a choice. Induction of the defense signaling compound jasmonic acid (JA) by H. zea feeding damage was highest in plants primarily dependent on rhizobia. Differences in rhizobial dependency on soybean did not appear to affect interactions with the phloem-feeding soybean aphid (Aphis glycines). Overall, our results suggest that rhizobia association can affect plant nutritional quality and the induction of defense signaling pathways and that these effects may influence herbivore feeding preferences and performance—though such effects may vary considerably for different classes of herbivores. PMID:24451132

  19. Symbiotic potential and survival of native rhizobia kept on different carriers

    PubMed Central

    Ruíz-Valdiviezo, Víctor Manuel; Canseco, Lucía María Cristina Ventura; Suárez, Luis Antonio Castillo; Gutiérrez-Miceli, Federico Antonio; Dendooven, Luc; Rincón-Rosales, Reiner

    2015-01-01

    Native rhizobia are ideal for use as commercial legume inoculants. The characteristics of the carrier used to store the inoculants are important for the survival and symbiotic potential of the rhizobia. The objective of this study was to investigate the effects of peat (PEAT), perlite sugarcane bagasse (PSB), carboxymethyl cellulose plus starch (CMCS), and yeast extract mannitol supplemented with mannitol (YEMM) on the survival, nodulation potential and N2 fixation capacity of the native strains Sinorhizobium mexicanum ITTG R7T and Rhizobium calliandrae LBP2-1T and of the reference strain Rhizobium etli CFN42T. A factorial design (4 × 3) with four repetitions was used to determine the symbiotic potential of the rhizobial strains. The survival of the strains was higher for PEAT (46% for strain LBP2-1T, 167% for strain CFN42T and 219% for strain ITTG R7T) than for the other carriers after 240 days, except for CFN42T kept on CMCS (225%). All the strains kept on the different carriers effectively nodulated common bean, with the lowest number of nodules found (5 nodules) when CFN42T was kept on CMCS and with the highest number of nodules found (28 nodules) when ITTG R7T was kept on PSB. The nitrogenase activity was the highest for ITTG R7T kept on PEAT (4911 μmol C2H4 per fresh weight nodule h−1); however, no activity was found when the strains were kept on YEMM. Thus, the survival and symbiotic potential of the rhizobia depended on the carrier used to store them. PMID:26413054

  20. Symbiotic potential and survival of native rhizobia kept on different carriers.

    PubMed

    Ruíz-Valdiviezo, Víctor Manuel; Canseco, Lucía María Cristina Ventura; Suárez, Luis Antonio Castillo; Gutiérrez-Miceli, Federico Antonio; Dendooven, Luc; Rincón-Rosales, Reiner

    2015-01-01

    Native rhizobia are ideal for use as commercial legume inoculants. The characteristics of the carrier used to store the inoculants are important for the survival and symbiotic potential of the rhizobia. The objective of this study was to investigate the effects of peat (PEAT), perlite sugarcane bagasse (PSB), carboxymethyl cellulose plus starch (CMCS), and yeast extract mannitol supplemented with mannitol (YEMM) on the survival, nodulation potential and N2 fixation capacity of the native strains Sinorhizobium mexicanum ITTG R7(T) and Rhizobium calliandrae LBP2-1(T) and of the reference strain Rhizobium etli CFN42(T). A factorial design (4 × 3) with four repetitions was used to determine the symbiotic potential of the rhizobial strains. The survival of the strains was higher for PEAT (46% for strain LBP2-1(T), 167% for strain CFN42(T) and 219% for strain ITTG R7(T)) than for the other carriers after 240 days, except for CFN42(T) kept on CMCS (225%). All the strains kept on the different carriers effectively nodulated common bean, with the lowest number of nodules found (5 nodules) when CFN42(T) was kept on CMCS and with the highest number of nodules found (28 nodules) when ITTG R7(T) was kept on PSB. The nitrogenase activity was the highest for ITTG R7(T) kept on PEAT (4911 μmol C2H4 per fresh weight nodule h(-1)); however, no activity was found when the strains were kept on YEMM. Thus, the survival and symbiotic potential of the rhizobia depended on the carrier used to store them. PMID:26413054

  1. Rhizobia survival in seeds coated with polyvinyl alcohol (PVA) electrospun nanofibres.

    PubMed

    Damasceno, Raquel; Roggia, Isabel; Pereira, Claudio; de Sá, Enilson

    2013-11-01

    The electrospinning technique of rhizobia immobilization in nanofibres is an innovative and promising alternative for reducing the harmful effects of environmental stress on bacteria strains in a possible inoculant nanotechnology product for use in agriculture. The use of polyvinyl alcohol (PVA) shows up as an effective polymer in cell encapsulation because of its physical characteristics, such as viscosity and power of scattering. The aim of these studies has been to evaluate the survival of rhizobia incorporated in PVA nanofibres, which were applied to soybean seed and then subjected to different storage times and exposure to fungicide. The maintenance of the symbiotic characteristics of the incorporated bacterial strains was also evaluated, noting the formation of nodules in the soybean seedlings. No significant differences in the cell survival at 0 h and after 24 h of storage were observed. After 48 h, a significant difference in the bacterial cell concentration of the seeds affixed with PVA nanofibres was observed. Exposure to the fungicide decreased the viability of the bacteria strains even when coated with the nanofibres. A larger number of nodules formed in soybean seedlings from seeds inoculated with rhizobia incorporated in PVA nanofibres than from seeds inoculated with rhizobia without PVA. Thus, the electrospinning technique is a great alternative to the usual protector inoculants because of its unprecedented capacity to control the release of bacteria. PMID:24206353

  2. A mechanistic molecular test of the plant-sanction hypothesis in legume-rhizobia mutualism

    NASA Astrophysics Data System (ADS)

    Marco, Diana E.; Pérez-Arnedo, Rebeca; Hidalgo-Perea, Ángeles; Olivares, José; Ruiz-Sainz, José E.; Sanjuán, Juan

    2009-09-01

    The origin and persistence of mutualism is difficult to explain because of the widespread occurrence of exploitative, 'cheating' partners. As a policing strategy stabilising intraspecific cooperation, host sanctions against non-N 2 fixing, cheating symbionts have been proposed to stabilise mutualism in legume-rhizobium symbiosis. Mechanism of penalisations would include decreased nodular rhizobial viability and/or early nodule senescence. We tested these potential mechanisms of penalisations in split-root experiments using two soybean varieties and two rhizobial strains, a cooperative, normal N 2-fixing strain and an isogenic non-fixing derivative. We found no differences in the number of viable rhizobia recovered from nodules and no differential expression of a nodular senescence molecular marker. Thus, our results do not support the hypothesis of plant sanctions acting against cheating rhizobia in our experimental conditions.

  3. Mixed infections may promote diversification of mutualistic symbionts: why are there ineffective rhizobia?

    PubMed

    Friesen, M L; Mathias, A

    2010-02-01

    While strategy variation is a key feature of symbiotic mutualisms, little work focuses on the origin of this diversity. Rhizobia strategies range from mutualistic nitrogen fixers to parasitic nonfixers that hoard plant resources to increase their own survival in soil. Host plants reward beneficial rhizobia with higher nodule growth rates, generating a trade-off between reproduction in nodules and subsequent survival in soil. However, hosts might not discriminate between strains in mixed infections, allowing nonfixing strains to escape sanctions. We construct an adaptive dynamics model of symbiotic nitrogen-fixation and find general situations where symbionts undergo adaptive diversification, but in most situations complete nonfixers do not evolve. Social conflict in mixed infections when symbionts face a survival-reproduction trade-off can drive the origin of some coexisting symbiont strategies, where less mutualistic strains exploit benefits generated by better mutualists. PMID:20002933

  4. Effects of a rock phosphate on indigenous rhizobia associated with Sesbania sesban.

    PubMed

    Sacko, Ousmane; Yattara, Inamoud Ibny; Lahbib, Messaoud; Neyra, Marc

    2012-03-01

    Tilemsi rock phosphate (TRP) of Mali is one of the most promising rock phosphate in West Africa for soil fertilization, but it is little used because of its insoluble form. The main objective of this study is to investigate TRP effects on rhizobia associated with the multipurpose leguminous tree Sesbania sesban grown on a sandy soil, poor in phosphorus and not sterilised. The experiment included treatments with and without TRP and was conducted during 105 days. At the end, 114 nodules have been collected and analysed by PCR/RFLP of 16S-23S intergenic spacer. Sixteen different RFLP profiles corresponding to different genomic groups of rhizobia have been detected. Five were dominant and present in both treatments. Five groups appear only in treatments without TRP whereas the six others are only in nodules of plants with TRP, suggesting a different capacity of natural phosphates solubilization by these strains. PMID:21168950

  5. Biodiversity and biogeography of rhizobia associated with common bean (Phaseolus vulgaris L.) in Shaanxi Province.

    PubMed

    Wang, Li; Cao, Ying; Wang, En Tao; Qiao, Ya Juan; Jiao, Shuo; Liu, Zhen Shan; Zhao, Liang; Wei, Ge Hong

    2016-05-01

    The biodiversity and biogeography of rhizobia associated with bean in Shaanxi Province were investigated. A total of 194 bacterial isolates from bean nodules collected from 13 sampling sites were characterized based on phylogenetic analyses of the 16S rRNA gene, the housekeeping genes recA, glnII and atpD, and the symbiotic genes nodC and nifH. Fifteen genospecies belonging to the genera Rhizobium, Agrobacterium, Ensifer, Bradyrhizobium and Ochrobactrum were defined among the isolates, with Rhizobium sp. II, Agrobacterium sp. II, E. fredii and R. phaseoli being the dominant groups. Four symbiotic gene lineages corresponding to Rhizobium sp. I, Rhizobium sp. II, R. phaseoli and B. liaoningense were detected in the nodC and nifH sequence analyses, indicating different origins for the symbiotic genes and their co-evolution with the chromosome of the bacteria. Moreover, the Ensifer isolates harbored symbiotic genes closely related to bean-nodulating Pararhizobium giardinii, indicating possible lateral gene transfer from Rhizobium to Ensifer. Correlation of rhizobial community composition with moisture, temperature, intercropping, soil features and nutrients were detected. All the results demonstrated a great diversity of bean rhizobia in Shaanxi that might be due to the adaptable evolution of the bean-nodulating rhizobia subjected to the diverse ecological conditions in the area. PMID:26966063

  6. Controlling the reproductive fate of rhizobia: how universal are legume sanctions?

    PubMed

    Oono, Ryoko; Denison, R Ford; Kiers, E Toby

    2009-01-01

    When a single host plant is infected by more than one strain of rhizobia, they face a tragedy of the commons. Although these rhizobia benefit collectively from nitrogen fixation, which increases host-plant photosynthesis, each strain might nonetheless increase its own reproduction, relative to competing strains, by diverting resources away from nitrogen fixation. Host sanctions can limit the evolutionary success of such rhizobial cheaters (strains that would otherwise benefit by fixing less nitrogen). Host sanctions have been shown in soybean (Glycine max) nodules, where the next generation of symbiotic rhizobia is descended from bacteroids (the differentiated cells that can fix nitrogen). Evidence for sanctions is less clear in legume species that induce rhizobial dimorphism inside their nodules. There, bacteroids are swollen and cannot reproduce regardless of how much nitrogen they fix, but sanctions could reduce reproduction of their undifferentiated clonemates within the same nodule. This rhizobial dimorphism can affect rhizobial evolution, including cheating options, in ways that may affect future generations of legumes. Both the importance of sanctions to hosts and possible physiological mechanisms for sanctions may depend on whether bacteroids are potentially reproductive. PMID:19594691

  7. Multiple steps control immunity during the intracellular accommodation of rhizobia

    PubMed Central

    Berrabah, Fathi; Ratet, Pascal; Gourion, Benjamin

    2015-01-01

    Medicago truncatula belongs to the legume family and forms symbiotic associations with nitrogen fixing bacteria, the rhizobia. During these interactions, the plants develop root nodules in which bacteria invade the plant cells and fix nitrogen for the benefit of the plant. Despite massive infection, legume nodules do not develop visible defence reactions, suggesting a special immune status of these organs. Some factors influencing rhizobium maintenance within the plant cells have been previously identified, such as the M. truncatula NCR peptides whose toxic effects are reduced by the bacterial protein BacA. In addition, DNF2, SymCRK, and RSD are M. truncatula genes required to avoid rhizobial death within the symbiotic cells. DNF2 and SymCRK are essential to prevent defence-like reactions in nodules after bacteria internalization into the symbiotic cells. Herein, we used a combination of genetics, histology and molecular biology approaches to investigate the relationship between the factors preventing bacterial death in the nodule cells. We show that the RSD gene is also required to repress plant defences in nodules. Upon inoculation with the bacA mutant, defence responses are observed only in the dnf2 mutant and not in the symCRK and rsd mutants. In addition, our data suggest that lack of nitrogen fixation by the bacterial partner triggers bacterial death in nodule cells after bacteroid differentiation. Together our data indicate that, after internalization, at least four independent mechanisms prevent bacterial death in the plant cell. These mechanisms involve successively: DNF2, BacA, SymCRK/RSD and bacterial ability to fix nitrogen. PMID:25682610

  8. Binding of isolated plant lectin by rhizobia during episodes of reduced gravity obtained by parabolic flight

    NASA Technical Reports Server (NTRS)

    Henry, R. L.; Green, P. D.; Wong, P. P.; Guikema, J. A.; Spooner, B. S. (Principal Investigator)

    1990-01-01

    Development of a legume root nodule is a complex process culminating in a plant/bacterial symbiosis possessing the capacity for biological dinitrogen fixation. Formation of root nodules is initiated by the binding and stabilization of rhizobia to plant root hairs, mediated in part by a receptor/ligand recognition system composed of lectins on the plant root surface and lectin-binding sites on the rhizobial cell surface. The dinitrogen fixation activity of these root nodules may be an important feature of enclosed, space-based life support systems, and may provide an ecological method to recycle nitrogen for amino acid production. However, the effects on nodule development of varied gravitational fields, or of root nutrient delivery hardware, remain unknown. We have investigated the effects of microgravity on root nodule formation, with preliminary experiments focused upon the receptor/ligand component. Microgravity, obtained during parabolic flight aboard NASA 930, has no apparent effect on the binding of purified lectin to rhizobia, a result that will facilitate forthcoming experiments using intact root tissues.

  9. NODULES WITH ACTIVATED DEFENSE 1 is required for maintenance of rhizobial endosymbiosis in Medicago truncatula.

    PubMed

    Wang, Chao; Yu, Haixiang; Luo, Li; Duan, Liujian; Cai, Liuyang; He, Xinxing; Wen, Jiangqi; Mysore, Kirankumar S; Li, Guoliang; Xiao, Aifang; Duanmu, Deqiang; Cao, Yangrong; Hong, Zonglie; Zhang, Zhongming

    2016-10-01

    The symbiotic interaction between legume plants and rhizobia results in the formation of root nodules, in which symbiotic plant cells host and harbor thousands of nitrogen-fixing rhizobia. Here, a Medicago truncatula nodules with activated defense 1 (nad1) mutant was identified using reverse genetics methods. The mutant phenotype was characterized using cell and molecular biology approaches. An RNA-sequencing technique was used to analyze the transcriptomic reprogramming of nad1 mutant nodules. In the nad1 mutant plants, rhizobial infection and propagation in infection threads are normal, whereas rhizobia and their symbiotic plant cells become necrotic immediately after rhizobia are released from infection threads into symbiotic cells of nodules. Defense-associated responses were detected in nad1 nodules. NAD1 is specifically present in root nodule symbiosis plants with the exception of Morus notabilis, and the transcript is highly induced in nodules. NAD1 encodes a small uncharacterized protein with two predicted transmembrane helices and is localized at the endoplasmic reticulum. Our data demonstrate a positive role for NAD1 in the maintenance of rhizobial endosymbiosis during nodulation. PMID:27245091

  10. SymRK and the nodule vascular system

    PubMed Central

    Sanchez-Lopez, Rosana; Jáuregui, David; Quinto, Carmen

    2012-01-01

    Symbiotic legume-rhizobia relationship leads to the formation of nitrogen-fixing nodules. Successful nodulation depends on the expression and cross-talk of a batttery of genes, among them SymRK (symbiosis receptor-like kinase), a leucine-rich repeat receptor-like kinase. SymRK is required for the rhizobia invasion of root hairs, as well as for the infection thread and symbiosome formation. Using immunolocalization and downregulation strategies we have recently provided evidence of a new function of PvSymRK in nodulation. We have found that a tight regulation of PvSymRK expression is required for the accurate development of the vascular bundle system in Phaseolus vulgaris nodules. PMID:22580688

  11. Ecological Indicators of Native Rhizobia in Tropical Soils †

    PubMed Central

    Woomer, Paul; Singleton, Paul W.; Bohlool, B. Ben

    1988-01-01

    The relationship between environment and abundance of rhizobia was described by determining the populations of root nodule bacteria at 14 diverse sites on the island of Maui. Mean annual rainfall at the sites ranged from 320 to 1,875 mm, elevation from 37 to 1,650 m, and soil pH from 4.6 to 7.9. Four different soil orders were represented in this study: inceptisols, mollisols, ultisols, and an oxisol. The rhizobial populations were determined by plant infection counts of five legumes (Trifolium repens, Medicago sativa, Vicia sativa, Leucaena leucocephala, and Macroptilium atropurpureum). Populations varied from 1.1 to 4.8 log10 cells per g of soil. The most frequently occurring rhizobia were Bradyrhizobium spp., which were present at 13 of 14 sites with a maximum of 4.8 log10 cells per g of soil. Rhizobium trifolii and R. leguminosarum occurred only at higher elevations. The presence of a particular Rhizobium or Bradyrhizobium sp. was correlated with the occurrence of its appropriate host legume. Total rhizobial populations were significantly correlated with mean annual rainfall, legume cover and shoot biomass, soil temperature, soil pH, and phosphorus retention. Regression models are presented which describe the relationship of legume hosts, soil climate, and soil fertility on native rhizobial populations. PMID:16347624

  12. Life histories of symbiotic rhizobia and mycorrhizal fungi.

    PubMed

    Denison, R Ford; Kiers, E Toby

    2011-09-27

    Research on life history strategies of microbial symbionts is key to understanding the evolution of cooperation with hosts, but also their survival between hosts. Rhizobia are soil bacteria known for fixing nitrogen inside legume root nodules. Arbuscular mycorrhizal (AM) fungi are ubiquitous root symbionts that provide plants with nutrients and other benefits. Both kinds of symbionts employ strategies to reproduce during symbiosis using host resources; to repopulate the soil; to survive in the soil between hosts; and to find and infect new hosts. Here we focus on the fitness of the microbial symbionts and how interactions at each of these stages has shaped microbial life-history strategies. During symbiosis, microbial fitness could be increased by diverting more resources to individual reproduction, but that may trigger fitness-reducing host sanctions. To survive in the soil, symbionts employ sophisticated strategies, such as persister formation for rhizobia and reversal of spore germination by mycorrhizae. Interactions among symbionts, from rhizobial quorum sensing to fusion of genetically distinct fungal hyphae, increase adaptive plasticity. The evolutionary implications of these interactions and of microbial strategies to repopulate and survive in the soil are largely unexplored. PMID:21959168

  13. R gene-controlled host specificity in the legume–rhizobia symbiosis

    PubMed Central

    Yang, Shengming; Tang, Fang; Gao, Muqiang; Krishnan, Hari B.; Zhu, Hongyan

    2010-01-01

    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 and Rfg1 that restrict nodulation with specific strains of Bradyrhizobium japonicum and Sinorhizobium fredii, respectively. We show that Rj2 and Rfg1 are allelic genes encoding a member of the Toll-interleukin receptor/nucleotide-binding site/leucine-rich repeat (TIR-NBS-LRR) class of plant resistance (R) proteins. The involvement of host R genes in the control of genotype-specific infection and nodulation reveals a common recognition mechanism underlying symbiotic and pathogenic host–bacteria interactions and suggests the existence of their cognate avirulence genes derived from rhizobia. This study suggests that establishment of a root nodule symbiosis requires the evasion of plant immune responses triggered by rhizobial effectors. PMID:20937853

  14. Diverse rhizobia associated with Sophora alopecuroides grown in different regions of Loess Plateau in China.

    PubMed

    Zhao, Longfei; Deng, Zhenshan; Yang, Wenquan; Cao, Ying; Wang, Entao; Wei, Gehong

    2010-12-01

    A total of seventy-five symbiotic bacterial strains isolated from root nodules of wild Sophora alopecuroides grown in different regions of China's Loess Plateau were characterized. Based on the combined RFLP patterns, thirty-five genotypes were defined among the rhizobia and they were classified into nine genomic species, including Mesorhizobium alhagi and M. gobiense as the main groups, as well as Agrobacterium tumefaciens, M. amorphae, Phyllobacterium trifolii, Rhizobium giardinii, R. indigoferae, Sinorhizobium fredii and S. meliloti as the minor groups according to the 16S rRNA and recA gene analyses. Five and three lineages of nodA and nifH were found, respectively, in these strains, implying that the symbiotic genes of the S. alopecuroides rhizobia had different origins or had divergently evolved. Results of correspondence analysis showed that there was a correlation between rhizobial genotypes and the geographic origins. Possible lateral transfer of the recA and 16S rRNA genes between the P. trifolii and A. tumefaciens strains, and that of symbiotic genes (nodA, nifH) between different genera, was shown by discrepancies of the phylogenetic relationships of the four gene loci. These results revealed diverse rhizobia associated with wild S. alopecuroides grown in different regions of China's Loess Plateau, and demonstrated for the first time the existence of symbiotic A. tumefaciens strains in root nodules of S. alopecuroides. PMID:20965680

  15. The plant growth promoting substance, lumichrome, mimics starch, and ethylene-associated symbiotic responses in lotus and tomato roots.

    PubMed

    Gouws, Liezel M; Botes, Eileen; Wiese, Anna J; Trenkamp, Sandra; Torres-Jerez, Ivone; Tang, Yuhong; Hills, Paul N; Usadel, Björn; Lloyd, James R; Fernie, Alisdair R; Kossmann, Jens; van der Merwe, Margaretha J

    2012-01-01

    Symbiosis involves responses that maintain the plant host and symbiotic partner's genetic program; yet these cues are far from elucidated. Here we describe the effects of lumichrome, a flavin identified from Rhizobium spp., applied to lotus (Lotus japonicus) and tomato (Solanum lycopersicum). Combined transcriptional and metabolite analyses suggest that both species shared common pathways that were altered in response to this application under replete, sterile conditions. These included genes involved in symbiosis, as well as transcriptional and metabolic responses related to enhanced starch accumulation and altered ethylene metabolism. Lumichrome priming also resulted in altered colonization with either Mesorhizobium loti (for lotus) or Glomus intraradices/G. mossea (for tomato). It enhanced nodule number but not nodule formation in lotus; while leading to enhanced hyphae initiation and delayed arbuscule maturation in tomato. PMID:22701462

  16. The Plant Growth Promoting Substance, Lumichrome, Mimics Starch, and Ethylene-Associated Symbiotic Responses in Lotus and Tomato Roots

    PubMed Central

    Gouws, Liezel M.; Botes, Eileen; Wiese, Anna J.; Trenkamp, Sandra; Torres-Jerez, Ivone; Tang, Yuhong; Hills, Paul N.; Usadel, Björn; Lloyd, James R.; Fernie, Alisdair R.; Kossmann, Jens; van der Merwe, Margaretha J.

    2012-01-01

    Symbiosis involves responses that maintain the plant host and symbiotic partner’s genetic program; yet these cues are far from elucidated. Here we describe the effects of lumichrome, a flavin identified from Rhizobium spp., applied to lotus (Lotus japonicus) and tomato (Solanum lycopersicum). Combined transcriptional and metabolite analyses suggest that both species shared common pathways that were altered in response to this application under replete, sterile conditions. These included genes involved in symbiosis, as well as transcriptional and metabolic responses related to enhanced starch accumulation and altered ethylene metabolism. Lumichrome priming also resulted in altered colonization with either Mesorhizobium loti (for lotus) or Glomus intraradices/G. mossea (for tomato). It enhanced nodule number but not nodule formation in lotus; while leading to enhanced hyphae initiation and delayed arbuscule maturation in tomato. PMID:22701462

  17. Regulatory patterns of a large family of defensin-like genes expressed in nodules of Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Root nodules are the symbiotic organ of legumes that house nitrogen-fixing bacteria. Many genes are specifically induced in nodules during the interactions between the host plant and symbiotic rhizobia. Information regarding the regulation of expression for most of these genes is lacking. One of the...

  18. Thyroid nodule

    MedlinePlus

    ... other thyroid blood tests Thyroid ultrasound Thyroid scan (nuclear medicine) Fine needle aspiration biopsy of the nodule or ... Guidelines for Clinical Practice for the Diagnosis and Management of Thyroid Nodules. Endocr Pract. 2010;16(suppl ...

  19. Does SUNN-SYMRK Crosstalk occur in Medicago truncatula for regulating nodule organogenesis?

    PubMed Central

    Saha, Sudip; DasGupta, Maitrayee

    2015-01-01

    Recently we reported that overexpression of intracellular kinase domain of Symbiosis Receptor Kinase (SYMRK-kd) hyperactivated spontaneous nodulation in Medicago truncatula indicating the importance of SYMRK ectodomain in restricting nodule number. To clarify whether sunn and sickle pathways were overcome by SYMRK-kd for hyperactivation of nodule organogenesis, we overexpressed SYMRK-kd in these mutants and analyzed for spontaneous nodulation in absence of rhizobia. Spontaneous nodulation in skl/SYMRK-kd roots was 2-fold higher than A17/SYMRK-kd roots indicating nodule organogenesis induced by SYMRK-kd to be ethylene sensitive. Intriguingly, sunn/SYMRK-kd roots failed to generate any spontaneous nodule which directly indicate the LRR-RLK SUNN to have a role in SYMRK-kd mediated nodule development under non-symbiotic conditions. We hypothesize a crosstalk between SUNN and SYMRK receptors for activation as well as restriction of nodule development. PMID:25893374

  20. Bacteriocin-Like Substances Produced by Rhizobium japonicum and Other Slow-Growing Rhizobia

    PubMed Central

    Gross, D. C.; Vidaver, A. K.

    1978-01-01

    Bacteriocin-like substances were commonly produced by slow-growing Rhizobium japonicum and cowpea rhizobia on an L-arabinose medium. Antagonism between strains of R. japonicum was not detected in vitro; however, such strains were often sensitive to some bacteriocins produced by cowpea rhizobia. Inhibitory zones (2 to 8 mm from colony margins), produced by 58 of 66 R. japonicum test strains, were reproducibly detected with Corynebacterium nebraskense as an indicator. Quantitative production was not related to symbiotic properties of effective strains, since nine noninfective strains and one ineffective strain produced bacteriocin. Eight R. japonicum strains that did not produce bacteriocin nevertheless formed effective nodules on soybeans. R. japonicum strains that produced bacteriocin in vitro had no antagonistic effect on nonproducer strains during soybean nodulation. Under controlled conditions, a nonproducer (3I1b135) predominated over a bacteriocin producer (3I1b6) when inoculated at 1:1 and 1:9 ratios. Depending on the particular ratio, up to 38% of the total nodules formed were infected with mixed combinations. The bacteriocin(s) had a restricted host range and antibiotic-like properties which included the ability to be dialyzed and resistance to heat (75 to 80°C, 30 min), Pronase, proteinase K, trypsin, ribonuclease, and deoxyribonuclease. R. japonicum strains representing genetic, serological, cultural, and geographic diversity were differentiated into three groups on the basis of bacteriocin production. Images PMID:570016

  1. Regulatory Patterns of a Large Family of Defensin-Like Genes Expressed in Nodules of Medicago truncatula

    PubMed Central

    Nallu, Sumitha; Silverstein, Kevin A. T.; Samac, Deborah A.; Bucciarelli, Bruna; Vance, Carroll P.; VandenBosch, Kathryn A.

    2013-01-01

    Root nodules are the symbiotic organ of legumes that house nitrogen-fixing bacteria. Many genes are specifically induced in nodules during the interactions between the host plant and symbiotic rhizobia. Information regarding the regulation of expression for most of these genes is lacking. One of the largest gene families expressed in the nodules of the model legume Medicago truncatula is the nodule cysteine-rich (NCR) group of defensin-like (DEFL) genes. We used a custom Affymetrix microarray to catalog the expression changes of 566 NCRs at different stages of nodule development. Additionally, bacterial mutants were used to understand the importance of the rhizobial partners in induction of NCRs. Expression of early NCRs was detected during the initial infection of rhizobia in nodules and expression continued as nodules became mature. Late NCRs were induced concomitantly with bacteroid development in the nodules. The induction of early and late NCRs was correlated with the number and morphology of rhizobia in the nodule. Conserved 41 to 50 bp motifs identified in the upstream 1,000 bp promoter regions of NCRs were required for promoter activity. These cis-element motifs were found to be unique to the NCR family among all annotated genes in the M. truncatula genome, although they contain sub-regions with clear similarity to known regulatory motifs involved in nodule-specific expression and temporal gene regulation. PMID:23573247

  2. Actinorhizal root nodule symbioses: what is signalling telling on the origins of nodulation?

    PubMed

    Svistoonoff, Sergio; Hocher, Valérie; Gherbi, Hassen

    2014-08-01

    Two groups of bacteria are able to induce the formation of nitrogen-fixing nodules: proteobacteria called rhizobia, which associate with Legumes or Parasponia and actinobateria from the genus Frankia which are able to interact with ∼220 species belonging to eight families called actinorhizal plants. Legumes and different lineages of actinorhizal plants differ in bacterial partners, nodule organogenesis and infection patterns and have independent evolutionary origins. However, recent technical achievements are revealing a variety of conserved signalling molecules and gene networks. Actinorhizal interactions display several primitive features and thus provide the ideal opportunity to determine the minimal molecular toolkit needed to build a nodule and to understand the evolution of root nodule symbioses. PMID:24691197

  3. Genetic diversity and distribution of rhizobia associated with the medicinal legumes Astragalus spp. and Hedysarum polybotrys in agricultural soils.

    PubMed

    Yan, Hui; Ji, Zhao Jun; Jiao, Yin Shan; Wang, En Tao; Chen, Wen Feng; Guo, Bao Lin; Chen, Wen Xin

    2016-03-01

    With the increasing cultivation of medicinal legumes in agricultural fields, the rhizobia associated with these plants are facing new stresses, mainly from fertilization and irrigation. In this study, investigations on the nodulation of three cultivated medicinal legumes, Astragalus mongholicus, Astragalus membranaceus and Hedysarum polybotrys were performed. Bacterial isolates from root nodules of these legumes were subjected to genetic diversity and multilocus sequence analyses. In addition, the distribution of nodule bacteria related to soil factors and host plants was studied. A total 367 bacterial isolates were obtained and 13 genospecies were identified. The predominant microsymbionts were identified as Mesorhizobium septentrionale, Mesorhizobium temperatum, Mesorhizobium tianshanense, Mesorhizobium ciceri and Mesorhizobium muleiense. M. septentrionale was found in most root nodules especially from legumes grown in the barren soils (with low available nitrogen and low organic carbon contents), while M. temperatum was predominant in nodules where the plants were grown in the nitrogen-rich fields. A. mongholicus tended to be associated with M. septentrionale, M. temperatum and M. ciceri in different soils, while A. membranaceus and H. polybotrys tended to be associated with M. tianshanense and M. septentrionale, respectively. This study showed that soil fertility may be the main determinant for the distribution of rhizobia associated with these cultured legume plants. PMID:26915496

  4. Commonalities and differences of T3SSs in rhizobia and plant pathogenic bacteria

    PubMed Central

    Tampakaki, Anastasia P.

    2014-01-01

    Plant pathogenic bacteria and rhizobia infect higher plants albeit the interactions with their hosts are principally distinct and lead to completely different phenotypic outcomes, either pathogenic or mutualistic, respectively. Bacterial protein delivery to plant host plays an essential role in determining the phenotypic outcome of plant-bacteria interactions. The involvement of type III secretion systems (T3SSs) in mediating animal- and plant-pathogen interactions was discovered in the mid-80's and is now recognized as a multiprotein nanomachine dedicated to trans-kingdom movement of effector proteins. The discovery of T3SS in bacteria with symbiotic lifestyles broadened its role beyond virulence. In most T3SS-positive bacterial pathogens, virulence is largely dependent on functional T3SSs, while in rhizobia the system is dispensable for nodulation and can affect positively or negatively the mutualistic associations with their hosts. This review focuses on recent comparative genome analyses in plant pathogens and rhizobia that uncovered similarities and variations among T3SSs in their genetic organization, regulatory networks and type III secreted proteins and discusses the evolutionary adaptations of T3SSs and type III secreted proteins that might account for the distinguishable phenotypes and host range characteristics of plant pathogens and symbionts. PMID:24723933

  5. Ethylene-mediated phenotypic plasticity in root nodule development on Sesbania rostrata

    PubMed Central

    Fernández-López, Manuel; Goormachtig, Sofie; Gao, Mengsheng; D’Haeze, Wim; Van Montagu, Marc; Holsters, Marcelle

    1998-01-01

    Leguminous plants in symbiosis with rhizobia form either indeterminate nodules with a persistent meristem or determinate nodules with a transient meristematic region. Sesbania rostrata was thought to possess determinate stem and root nodules. However, the nature of nodule development is hybrid, and the early stages resemble those of indeterminate nodules. Here we show that, depending on the environmental conditions, mature root nodules can be of the indeterminate type. In situ hybridizations with molecular markers for plant cell division, as well as the patterns of bacterial nod and nif gene expression, confirmed the indeterminate nature of 30-day-old functional root nodules. Experimental data provide evidence that the switch in nodule type is mediated by the plant hormone ethylene. PMID:9770553

  6. Genotypic and phenotypic diversity of rhizobia isolated from Lathyrus japonicus indigenous to Japan.

    PubMed

    Aoki, Seishiro; Kondo, Tetsuya; Prévost, Danielle; Nakata, Sayuri; Kajita, Tadashi; Ito, Motomi

    2010-11-01

    Sixty-one rhizobial strains from Lathyrus japonicus nodules growing on the seashore in Japan were characterized and compared to two strains from Canada. The PCR-based method was used to identify test strains with novel taxonomic markers that were designed to discriminate between all known Lathyrus rhizobia. Three genomic groups (I, II, and III) were finally identified using RAPD, RFLP, and phylogenetic analyses. Strains in genomic group I (related to Rhizobium leguminosarum) were divided into two subgroups (Ia and Ib) and subgroup Ia was related to biovar viciae. Strains in subgroup Ib, which were all isolated from Japanese sea pea, belonged to a distinct group from other rhizobial groups in the recA phylogeny and PCR-based grouping, and were more tolerant to salt than the isolate from an inland legume. Test strains in genomic groups II and III belonged to a single clade with the reference strains of R. pisi, R. etli, and R. phaseoli in the 16S rRNA phylogeny. The PCR-based method and phylogenetic analysis of recA revealed that genomic group II was related to R. pisi. The analyses also showed that genomic group III harbored a mixed chromosomal sequence of different genomic groups, suggesting a recent horizontal gene transfer between diverse rhizobia. Although two Canadian strains belonged to subgroup Ia, molecular and physiological analyses showed the divergence between Canadian and Japanese strains. Phylogenetic analysis of nod genes divided the rhizobial strains into several groups that reflected the host range of rhizobia. Symbiosis between dispersing legumes and rhizobia at seashore is discussed. PMID:20851546

  7. Flavonoids and Auxin Transport Inhibitors Rescue Symbiotic Nodulation in the Medicago truncatula Cytokinin Perception Mutant cre1

    PubMed Central

    Ng, Jason Liang Pin; Hassan, Samira; Truong, Thy T.; Hocart, Charles H.; Laffont, Carole; Frugier, Florian; Mathesius, Ulrike

    2015-01-01

    Initiation of symbiotic nodules in legumes requires cytokinin signaling, but its mechanism of action is largely unknown. Here, we tested whether the failure to initiate nodules in the Medicago truncatula cytokinin perception mutant cre1 (cytokinin response1) is due to its altered ability to regulate auxin transport, auxin accumulation, and induction of flavonoids. We found that in the cre1 mutant, symbiotic rhizobia cannot locally alter acro- and basipetal auxin transport during nodule initiation and that these mutants show reduced auxin (indole-3-acetic acid) accumulation and auxin responses compared with the wild type. Quantification of flavonoids, which can act as endogenous auxin transport inhibitors, showed a deficiency in the induction of free naringenin, isoliquiritigenin, quercetin, and hesperetin in cre1 roots compared with wild-type roots 24 h after inoculation with rhizobia. Coinoculation of roots with rhizobia and the flavonoids naringenin, isoliquiritigenin, and kaempferol, or with the synthetic auxin transport inhibitor 2,3,5,-triiodobenzoic acid, rescued nodulation efficiency in cre1 mutants and allowed auxin transport control in response to rhizobia. Our results suggest that CRE1-dependent cytokinin signaling leads to nodule initiation through the regulation of flavonoid accumulation required for local alteration of polar auxin transport and subsequent auxin accumulation in cortical cells during the early stages of nodulation. PMID:26253705

  8. Hormonal Control of Lateral Root and Nodule Development in Legumes

    PubMed Central

    Bensmihen, Sandra

    2015-01-01

    Many plants can establish symbioses with nitrogen-fixing bacteria, some of which lead to nodulation, including legumes. Indeed, in the rhizobium/legume symbiosis, new root organs, called nodules, are formed by the plant in order to host the rhizobia in protective conditions, optimized for nitrogen fixation. In this way, these plants can benefit from the reduction of atmospheric dinitrogen into ammonia by the hosted bacteria, and in exchange the plant provides the rhizobia with a carbon source. Since this symbiosis is costly for the plant it is highly regulated. Both legume nodule and lateral root organogenesis involve divisions of the root inner tissues, and both developmental programs are tightly controlled by plant hormones. In fact, most of the major plant hormones, such as auxin, cytokinins, abscisic acid, and strigolactones, control both lateral root formation and nodule organogenesis, but often in an opposite manner. This suggests that the sensitivity of legume plants to some phytohormones could be linked to the antagonism that exists between the processes of nodulation and lateral root formation. Here, we will review the implication of some major phytohormones in lateral root formation in legumes, compare them with their roles in nodulation, and discuss specificities and divergences from non-legume eudicot plants such as Arabidopsis thaliana. PMID:27135340

  9. Overexpression of flavodoxin in bacteroids induces changes in antioxidant metabolism leading to delayed senescence and starch accumulation in alfalfa root nodules.

    PubMed

    Redondo, Francisco J; de la Peña, Teodoro Coba; Morcillo, César N; Lucas, M Mercedes; Pueyo, José J

    2009-02-01

    Sinorhizobium meliloti cells were engineered to overexpress Anabaena variabilis flavodoxin, a protein that is involved in the response to oxidative stress. Nodule natural senescence was characterized in alfalfa (Medicago sativa) plants nodulated by the flavodoxin-overexpressing rhizobia or the corresponding control bacteria. The decline of nitrogenase activity and the nodule structural and ultrastructural alterations that are associated with nodule senescence were significantly delayed in flavodoxin-expressing nodules. Substantial changes in nodule antioxidant metabolism, involving antioxidant enzymes and ascorbate-glutathione cycle enzymes and metabolites, were detected in flavodoxin-containing nodules. Lipid peroxidation was also significantly lower in flavodoxin-expressing nodules than in control nodules. The observed amelioration of the oxidative balance suggests that the delay in nodule senescence was most likely due to a role of the protein in reactive oxygen species detoxification. Flavodoxin overexpression also led to high starch accumulation in nodules, without reduction of the nitrogen-fixing activity. PMID:19098093

  10. Small-peptide signals that control root nodule number, development, and symbiosis.

    PubMed

    Djordjevic, Michael A; Mohd-Radzman, Nadiatul A; Imin, Nijat

    2015-08-01

    Many legumes have the capacity to enter into a symbiotic association with soil bacteria generically called 'rhizobia' that results in the formation of new lateral organs on roots called nodules within which the rhizobia fix atmospheric nitrogen (N). Up to 200 million tonnes of N per annum is fixed by this association. Therefore, this symbiosis plays an integral role in the N cycle and is exploited in agriculture to support the sustainable fixation of N for cropping and animal production in developing and developed nations. Root nodulation is an expendable developmental process and competency for nodulation is coupled to low-N conditions. Both nodule initiation and development is suppressed under high-N conditions. Although root nodule formation enables sufficient N to be fixed for legumes to grow under N-deficient conditions, the carbon cost is high and nodule number is tightly regulated by local and systemic mechanisms. How legumes co-ordinate nodule formation with the other main organs of nutrient acquisition, lateral roots, is not fully understood. Independent mechanisms appear to regulate lateral roots and nodules under low- and high-N regimes. Recently, several signalling peptides have been implicated in the local and systemic regulation of nodule and lateral root formation. Other peptide classes control the symbiotic interaction of rhizobia with the host. This review focuses on the roles played by signalling peptides during the early stages of root nodule formation, in the control of nodule number, and in the establishment of symbiosis. Here, we highlight the latest findings and the gaps in our understanding of these processes. PMID:26249310

  11. Legume NADPH Oxidases Have Crucial Roles at Different Stages of Nodulation

    PubMed Central

    Montiel, Jesús; Arthikala, Manoj-Kumar; Cárdenas, Luis; Quinto, Carmen

    2016-01-01

    Plant NADPH oxidases, formerly known as respiratory burst oxidase homologues (RBOHs), are plasma membrane enzymes dedicated to reactive oxygen species (ROS) production. These oxidases are implicated in a wide variety of processes, ranging from tissue and organ growth and development to signaling pathways in response to abiotic and biotic stimuli. Research on the roles of RBOHs in the plant’s response to biotic stresses has mainly focused on plant-pathogen interactions; nonetheless, recent findings have shown that these oxidases are also involved in the legume-rhizobia symbiosis. The legume-rhizobia symbiosis leads to the formation of the root nodule, where rhizobia reduce atmospheric nitrogen to ammonia. A complex signaling and developmental pathway in the legume root hair and root facilitate rhizobial entrance and nodule organogenesis, respectively. Interestingly, several reports demonstrate that RBOH-mediated ROS production displays versatile roles at different stages of nodulation. The evidence collected to date indicates that ROS act as signaling molecules that regulate rhizobial invasion and also function in nodule senescence. This review summarizes discoveries that support the key and versatile roles of various RBOH members in the legume-rhizobia symbiosis. PMID:27213330

  12. Legume NADPH Oxidases Have Crucial Roles at Different Stages of Nodulation.

    PubMed

    Montiel, Jesús; Arthikala, Manoj-Kumar; Cárdenas, Luis; Quinto, Carmen

    2016-01-01

    Plant NADPH oxidases, formerly known as respiratory burst oxidase homologues (RBOHs), are plasma membrane enzymes dedicated to reactive oxygen species (ROS) production. These oxidases are implicated in a wide variety of processes, ranging from tissue and organ growth and development to signaling pathways in response to abiotic and biotic stimuli. Research on the roles of RBOHs in the plant's response to biotic stresses has mainly focused on plant-pathogen interactions; nonetheless, recent findings have shown that these oxidases are also involved in the legume-rhizobia symbiosis. The legume-rhizobia symbiosis leads to the formation of the root nodule, where rhizobia reduce atmospheric nitrogen to ammonia. A complex signaling and developmental pathway in the legume root hair and root facilitate rhizobial entrance and nodule organogenesis, respectively. Interestingly, several reports demonstrate that RBOH-mediated ROS production displays versatile roles at different stages of nodulation. The evidence collected to date indicates that ROS act as signaling molecules that regulate rhizobial invasion and also function in nodule senescence. This review summarizes discoveries that support the key and versatile roles of various RBOH members in the legume-rhizobia symbiosis. PMID:27213330

  13. The Symbiotic Performance of Chickpea Rhizobia Can Be Improved by Additional Copies of the clpB Chaperone Gene.

    PubMed

    Paço, Ana; Brígido, Clarisse; Alexandre, Ana; Mateos, Pedro F; Oliveira, Solange

    2016-01-01

    The ClpB chaperone is known to be involved in bacterial stress response. Moreover, recent studies suggest that this protein has also a role in the chickpea-rhizobia symbiosis. In order to improve both stress tolerance and symbiotic performance of a chickpea microsymbiont, the Mesorhizobium mediterraneum UPM-Ca36T strain was genetically transformed with pPHU231 containing an extra-copy of the clpB gene. To investigate if the clpB-transformed strain displays an improved stress tolerance, bacterial growth was evaluated under heat and acid stress conditions. In addition, the effect of the extra-copies of the clpB gene in the symbiotic performance was evaluated using plant growth assays (hydroponic and pot trials). The clpB-transformed strain is more tolerant to heat shock than the strain transformed with pPHU231, supporting the involvement of ClpB in rhizobia heat shock tolerance. Both plant growth assays showed that ClpB has an important role in chickpea-rhizobia symbiosis. The nodulation kinetics analysis showed a higher rate of nodule appearance with the clpB-transformed strain. This strain also induced a greater number of nodules and, more notably, its symbiotic effectiveness increased ~60% at pH5 and 83% at pH7, compared to the wild-type strain. Furthermore, a higher frequency of root hair curling was also observed in plants inoculated with the clpB-transformed strain, compared to the wild-type strain. The superior root hair curling induction, nodulation ability and symbiotic effectiveness of the clpB-transformed strain may be explained by an increased expression of symbiosis genes. Indeed, higher transcript levels of the nodulation genes nodA and nodC (~3 folds) were detected in the clpB-transformed strain. The improvement of rhizobia by addition of extra-copies of the clpB gene may be a promising strategy to obtain strains with enhanced stress tolerance and symbiotic effectiveness, thus contributing to their success as crop inoculants, particularly under

  14. Rhizobia Indigenous to the Okavango Region in Sub-Saharan Africa: Diversity, Adaptations, and Host Specificity

    PubMed Central

    Grönemeyer, Jann L.; Kulkarni, Ajinkya; Berkelmann, Dirk; Hurek, Thomas

    2014-01-01

    The rhizobial community indigenous to the Okavango region has not yet been characterized. The isolation of indigenous rhizobia can provide a basis for the formulation of a rhizobial inoculant. Moreover, their identification and characterization contribute to the general understanding of species distribution and ecology. Isolates were obtained from nodules of local varieties of the pulses cowpea, Bambara groundnut, peanut, hyacinth bean, and common bean. Ninety-one of them were identified by BOX repetitive element PCR (BOX-PCR) and sequence analyses of the 16S-23S rRNA internally transcribed spacer (ITS) and the recA, glnII, rpoB, and nifH genes. A striking geographical distribution was observed. Bradyrhizobium pachyrhizi dominated at sampling sites in Angola which were characterized by acid soils and a semihumid climate. Isolates from the semiarid sampling sites in Namibia were more diverse, with most of them being related to Bradyrhizobium yuanmingense and Bradyrhizobium daqingense. Host plant specificity was observed only for hyacinth bean, which was nodulated by rhizobia presumably representing yet-undescribed species. Furthermore, the isolates were characterized with respect to their adaptation to high temperatures, drought, and local host plants. The adaptation experiments revealed that the Namibian isolates shared an exceptionally high temperature tolerance, but none of the isolates showed considerable adaptation to drought. Moreover, the isolates' performance on different local hosts showed variable results, with most Namibian isolates inducing better nodulation on peanut and hyacinth bean than the Angolan strains. The local predominance of distinct genotypes implies that indigenous strains may exhibit a better performance in inoculant formulations. PMID:25239908

  15. Effects of biotic and abiotic constraints on the symbiosis between rhizobia and the tropical leguminous trees Acacia and Prosopis.

    PubMed

    Räsänen, Leena A; Lindström, Kristina

    2003-10-01

    N2-fixing, drought tolerant and multipurpose Acacia and Prosopis species are appropriate trees for reforestation of degraded areas in arid and semiarid regions of the tropics and subtropics. Acacia and Prosopis trees form N2-fixing nodules with a wide range of rhizobia, for example African acacias mainly with Sinorhizobium sp. and Mesorhizobium sp., and Australian acacias with Bradyrhizobium sp. Although dry and hot seasons restrict formation of N2-fixing nodules on Acacia and Prosopis spp., fully grown trees and their symbiotic partners are well adapted to survive in harsh growth conditions. This review on one hand deals with major constraints of arid and semiarid soils, i.e. drought, salinity and high soil temperature, which affect growth of trees and rhizobia, and on the other hand with adaptation mechanisms by which both organisms survive through unfavourable periods. In addition, defects in infection and nodulation processes due to various abiotic and biotic constraints are reviewed. This knowledge is important when Acacia and Prosopis seedlings are used for forestation of degraded areas in arid and semiarid tropics. PMID:15242281

  16. Reassimilation of ammonium in Lotus japonicus.

    PubMed

    Betti, Marco; García-Calderón, Margarita; Pérez-Delgado, Carmen M; Credali, Alfredo; Pal'ove-Balang, Peter; Estivill, Guillermo; Repčák, Miroslav; Vega, José M; Galván, Francisco; Márquez, Antonio J

    2014-10-01

    This review summarizes the most recent results obtained in the analysis of two important metabolic pathways involved in the release of internal sources of ammonium in the model legume Lotus japonicus: photorespiratory metabolism and asparagine breakdown mediated by aparaginase (NSE). The use of photorespiratory mutants deficient in plastidic glutamine synthetase (GS2) enabled us to investigate the transcriptomics and metabolomic changes associated with photorespiratory ammonium accumulation in this plant. The results obtained indicate the existence of a coordinate regulation of genes involved in photorespiratory metabolism. Other types of evidence illustrate the multiple interconnections existing among the photorespiratory pathway and other processes such as intermediate metabolism, nodule function, and secondary metabolism in this plant, all of which are substantially affected in GS2-deficient mutants because of the impairment of the photorespiratory cycle. Finally, the importance of asparagine metabolism in L. japonicus is highlighted because of the fact that asparagine constitutes the vast majority of the reduced nitrogen translocated between different organs of this plant. The different types of NSE enzymes and genes which are present in L. japonicus are described. There is a particular focus on the most abundant K(+)-dependent LjNSE1 isoform and how TILLING mutants were used to demonstrate by reverse genetics the importance of this particular isoform in plant growth and seed production. PMID:24948681

  17. Importance of rhizobia in Agriculture: potential of the commercial inoculants and native strains for improving legume yields in different land-use systems

    NASA Astrophysics Data System (ADS)

    Lesueur, D.; Atieno, M.; Mathu, S.; Herrmann, L.

    2012-04-01

    Legumes play an important role in the traditional diets of many regions throughout the world because they provide a multitude of benefits to both the soil and other crops grown in combination with them or following them in several cropping systems. The ability of legumes to fix atmospheric nitrogen in association with rhizobia gives them the capacity to grow in very degraded soils. But do we have to systematically inoculate legumes? For example our results suggested that the systematic inoculation of both cowpea and green gram in Kenya with commercial inoculants to improve yields is not really justified, native strains performing better than inoculated strains. But when native rhizobia nodulating legumes are not naturally present, application of rhizobial inoculants is very commonly used. Our results showed that the utilization of effective good-quality rhizobial inoculants by farmers have a real potential to improve legume yields in unfertile soils requesting high applications of mineral fertilizers. For example an effective soybean commercial inoculants was tested in different locations in Kenya (in about 150 farms in 3 mandate areas presenting different soil characteristics and environmental conditions). Application of the rhizobial inoculant significantly increased the soybean yields in all mandate areas (about 75% of the farms). Nodule occupancy analysis showed that a high number of nodules occupied by the inoculated strain did not obviously lead to an increase of soybean production. Soil factors (pH, P, C, N…) seemed to affect the inoculant efficiency whether the strain is occupying the nodules or not. Our statistic analysis showed that soil pH significantly affected nodulation and yield, though the effect was variable depending on the region. We concluded that the competitiveness of rhizobial strains might not be the main factor explaining the effect (or lack of) of legumes inoculation in the field. Another study was aiming to assess if several factors

  18. LIN, a novel type of U-box/WD40 protein, controls early infection by rhizobia in legumes.

    PubMed

    Kiss, Ernö; Oláh, Boglárka; Kaló, Péter; Morales, Monica; Heckmann, Anne B; Borbola, Andrea; Lózsa, Anita; Kontár, Katalin; Middleton, Patrick; Downie, J Allan; Oldroyd, Giles E D; Endre, Gabriella

    2009-11-01

    The formation of a nitrogen-fixing nodule requires the coordinated development of rhizobial colonization and nodule organogenesis. Based on its mutant phenotype, lumpy infections (lin), LIN functions at an early stage of the rhizobial symbiotic process, required for both infection thread growth in root hair cells and the further development of nodule primordia. We show that spontaneous nodulation activated by the calcium- and calmodulin-dependent protein kinase is independent of LIN; thus, LIN is not necessary for nodule organogenesis. From this, we infer that LIN predominantly functions during rhizobial colonization and that the abortion of this process in lin mutants leads to a suppression of nodule development. Here, we identify the LIN gene in Medicago truncatula and Lotus japonicus, showing that it codes for a predicted E3 ubiquitin ligase containing a highly conserved U-box and WD40 repeat domains. Ubiquitin-mediated protein degradation is a universal mechanism to regulate many biological processes by eliminating rate-limiting enzymes and key components such as transcription factors. We propose that LIN is a regulator of the component(s) of the nodulation factor signal transduction pathway and that its function is required for correct temporal and spatial activity of the target protein(s). PMID:19776163

  19. Photosynthate partitioning and nitrogen fixation of alfalfa and birdsfoot trefoil. [Lotus corniculatus L. ; Medicago sativa L

    SciTech Connect

    Shieh, W.J.

    1985-01-01

    Nodule mass and number are usually correlated with rates of nitrogen fixation in legumes. Birdsfoot trefoil (Lotus corniculatus L.) with more than twice the nodule number and mass, however, fixes far less nitrogen than alfalfa (Medicago sativa L.) at the same age. In this research, photosynthesis and photosynthate partitioning and utilization in relation to nitrogen fixation of alfalfa and birdsfoot trefoil were examined in order to determine their relationship to nitrogen fixation potential. Photosynthate to nodules was studied using /sup 14/CO/sub 2/ labeling techniques. Partitioning patterns were altered by shading and dark depletion treatments. Efficiency of photosynthate utilization was examined by determining turnover of /sup 14/C photosynthate in nodule metabolites and by studying rates of cyanide-resistant and cyanide-sensitive O/sub 2/ uptake. Alfalfa nodule activity was greater than trefoil expressed on a hole pot or nodule dry weight basis. Both shading and dark treatments significantly reduced nodule activity as estimated by the acetylene reduction assay. Shoots of both species were found to be the dominant sinks for photosynthate. Percentage /sup 14/C recovered in alfalfa roots was more than twice that of trefoil at 1,2,3,4 and 24 h after labeling. Greater relative specific radioactivity (RSA) in nodules of both species suggests that they were stronger sinks for current photosynthate than roots.

  20. Biodiversity and Biogeography of Rhizobia Associated with Soybean Plants Grown in the North China Plain ▿ †

    PubMed Central

    Zhang, Yan Ming; Li, Ying; Chen, Wen Feng; Wang, En Tao; Tian, Chang Fu; Li, Qin Qin; Zhang, Yun Zeng; Sui, Xin Hua; Chen, Wen Xin

    2011-01-01

    As the putative center of origin for soybean and the second largest region of soybean production in China, the North China Plain covers temperate and subtropical regions with diverse soil characteristics. However, the soybean rhizobia in this plain have not been sufficiently studied. To investigate the biodiversity and biogeography of soybean rhizobia in this plain, a total of 309 isolates of symbiotic bacteria from the soybean nodules collected from 16 sampling sites were studied by molecular characterization. These isolates were classified into 10 genospecies belonging to the genera Sinorhizobium and Bradyrhizobium, including four novel groups, with S. fredii (68.28%) as the dominant group. The phylogeny of symbiotic genes nodC and nifH defined four lineages among the isolates associated with Sinorhizobium fredii, Bradyrhizobium elkanii, B. japonicum, and B. yuanmingense, demonstrating the different origins of symbiotic genes and their coevolution with the chromosome. The possible lateral transfer of symbiotic genes was detected in several cases. The association between soil factors (available N, P, and K and pH) and the distribution of genospecies suggest clear biogeographic patterns: Sinorhizobium spp. were superdominant in sampling sites with alkaline-saline soils, while Bradyrhizobium spp. were more abundant in neutral soils. This study clarified the biodiversity and biogeography of soybean rhizobia in the North China Plain. PMID:21784912

  1. Bioremediation of cadmium contaminated soil using symbiosis between leguminous plant and recombinant rhizobia with the MTL4 and the PCS genes.

    PubMed

    Ike, Akiko; Sriprang, Rutchadaporn; Ono, Hisayo; Murooka, Yoshikatsu; Yamashita, Mitsuo

    2007-01-01

    Cadmium contamination in rice grains is one of the important issues in Asian countries. We have developed a novel bio-remediation system based on the symbiosis between leguminous plant and genetically engineered rhizobia. We designed two types of recombinant rhizobia, carrying two genes, synthetic tetrameric metallothionein (MTL4) and cDNA encoding phytochelatin synthase from Arabidopsis thaliana (AtPCS). The MTL4 and AtPCS genes were transferred to Mesorhizobium huakuii subsp. rengei B3, which can infect and form nodules on Chinese milk vetch, Astragalus sinicus. The two genes were fused to the nolB or nifH promoter, which generated nodule specific expression of these genes in strain B3. The two recombinant strains, B3(pMPnolBMTL4nifHPCS) and B3::nifHMTL4(pMPnifHPCS), showed 25 and 12-fold increase in Cd concentration, in the free-living cells, respectively. When these recombinant strains established the symbiotic relationship with A. sinicus, the symbionts increased Cd accumulation in nodules by two-fold in hydroponic culture. The expression of the both MTL4 and AtPCS genes showed additive effect on cadmium accumulation in nodules. We also applied these recombinant bacteria to rice paddy soil polluted with Cd (1mgkg(-1) dry weight soil). The accumulation of Cd increased not only in nodules but also in the roots of A. sinicus infected by the recombinant rhizobia. The accumulation of Cd in the plant roots infected by B3(pMPnolBMTL4nifHPCS) achieved three-fold than that by the wild-type B3. After two months of cultivation of the symbiont, a maximum of 9% of Cd in paddy soil was removed. Thus, the symbiosis will be useful in phytoremediation for heavy metals. PMID:16950497

  2. Transition Metal Transport in Plants and Associated Endosymbionts: Arbuscular Mycorrhizal Fungi and Rhizobia.

    PubMed

    González-Guerrero, Manuel; Escudero, Viviana; Saéz, Ángela; Tejada-Jiménez, Manuel

    2016-01-01

    Transition metals such as iron, copper, zinc, or molybdenum are essential nutrients for plants. These elements are involved in almost every biological process, including photosynthesis, tolerance to biotic and abiotic stress, or symbiotic nitrogen fixation. However, plants often grow in soils with limiting metallic oligonutrient bioavailability. Consequently, to ensure the proper metal levels, plants have developed a complex metal uptake and distribution system, that not only involves the plant itself, but also its associated microorganisms. These microorganisms can simply increase metal solubility in soils and making them more accessible to the host plant, as well as induce the plant metal deficiency response, or directly deliver transition elements to cortical cells. Other, instead of providing metals, can act as metal sinks, such as endosymbiotic rhizobia in legume nodules that requires relatively large amounts to carry out nitrogen fixation. In this review, we propose to do an overview of metal transport mechanisms in the plant-microbe system, emphasizing the role of arbuscular mycorrhizal fungi and endosymbiotic rhizobia. PMID:27524990

  3. Pesticides reduce symbiotic efficiency of nitrogen-fixing rhizobia and host plants.

    PubMed

    Fox, Jennifer E; Gulledge, Jay; Engelhaupt, Erika; Burow, Matthew E; McLachlan, John A

    2007-06-12

    Unprecedented agricultural intensification and increased crop yield will be necessary to feed the burgeoning world population, whose global food demand is projected to double in the next 50 years. Although grain production has doubled in the past four decades, largely because of the widespread use of synthetic nitrogenous fertilizers, pesticides, and irrigation promoted by the "Green Revolution," this rate of increased agricultural output is unsustainable because of declining crop yields and environmental impacts of modern agricultural practices. The last 20 years have seen diminishing returns in crop yield in response to increased application of fertilizers, which cannot be completely explained by current ecological models. A common strategy to reduce dependence on nitrogenous fertilizers is the production of leguminous crops, which fix atmospheric nitrogen via symbiosis with nitrogen-fixing rhizobia bacteria, in rotation with nonleguminous crops. Here we show previously undescribed in vivo evidence that a subset of organochlorine pesticides, agrichemicals, and environmental contaminants induces a symbiotic phenotype of inhibited or delayed recruitment of rhizobia bacteria to host plant roots, fewer root nodules produced, lower rates of nitrogenase activity, and a reduction in overall plant yield at time of harvest. The environmental consequences of synthetic chemicals compromising symbiotic nitrogen fixation are increased dependence on synthetic nitrogenous fertilizer, reduced soil fertility, and unsustainable long-term crop yields. PMID:17548832

  4. Transition Metal Transport in Plants and Associated Endosymbionts: Arbuscular Mycorrhizal Fungi and Rhizobia

    PubMed Central

    González-Guerrero, Manuel; Escudero, Viviana; Saéz, Ángela; Tejada-Jiménez, Manuel

    2016-01-01

    Transition metals such as iron, copper, zinc, or molybdenum are essential nutrients for plants. These elements are involved in almost every biological process, including photosynthesis, tolerance to biotic and abiotic stress, or symbiotic nitrogen fixation. However, plants often grow in soils with limiting metallic oligonutrient bioavailability. Consequently, to ensure the proper metal levels, plants have developed a complex metal uptake and distribution system, that not only involves the plant itself, but also its associated microorganisms. These microorganisms can simply increase metal solubility in soils and making them more accessible to the host plant, as well as induce the plant metal deficiency response, or directly deliver transition elements to cortical cells. Other, instead of providing metals, can act as metal sinks, such as endosymbiotic rhizobia in legume nodules that requires relatively large amounts to carry out nitrogen fixation. In this review, we propose to do an overview of metal transport mechanisms in the plant–microbe system, emphasizing the role of arbuscular mycorrhizal fungi and endosymbiotic rhizobia. PMID:27524990

  5. Genetic diversity of Rhizobia isolates from Amazon soils using cowpea (Vigna unguiculata) as trap plant

    PubMed Central

    Silva, F.V.; Simões-Araújo, J.L.; Silva Júnior, J.P.; Xavier, G.R.; Rumjanek, N.G.

    2012-01-01

    The aim of this work was to characterize rhizobia isolated from the root nodules of cowpea (Vigna unguiculata) plants cultivated in Amazon soils samples by means of ARDRA (Amplified rDNA Restriction Analysis) and sequencing analysis, to know their phylogenetic relationships. The 16S rRNA gene of rhizobia was amplified by PCR (polymerase chain reaction) using universal primers Y1 and Y3. The amplification products were analyzed by the restriction enzymes HinfI, MspI and DdeI and also sequenced with Y1, Y3 and six intermediate primers. The clustering analysis based on ARDRA profiles separated the Amazon isolates in three subgroups, which formed a group apart from the reference isolates of Bradyrhizobium japonicum and Bradyrhizobium elkanii. The clustering analysis of 16S rRNA gene sequences showed that the fast-growing isolates had similarity with Enterobacter, Rhizobium, Klebsiella and Bradyrhizobium and all the slow-growing clustered close to Bradyrhizobium. PMID:24031880

  6. NODULE ROOT and COCHLEATA Maintain Nodule Development and Are Legume Orthologs of Arabidopsis BLADE-ON-PETIOLE Genes[W][OA

    PubMed Central

    Couzigou, Jean-Malo; Zhukov, Vladimir; Mondy, Samuel; Abu el Heba, Ghada; Cosson, Viviane; Ellis, T.H. Noel; Ambrose, Mike; Wen, Jiangqi; Tadege, Million; Tikhonovich, Igor; Mysore, Kirankumar S.; Putterill, Joanna; Hofer, Julie; Borisov, Alexei Y.; Ratet, Pascal

    2012-01-01

    During their symbiotic interaction with rhizobia, legume plants develop symbiosis-specific organs on their roots, called nodules, that house nitrogen-fixing bacteria. The molecular mechanisms governing the identity and maintenance of these organs are unknown. Using Medicago truncatula nodule root (noot) mutants and pea (Pisum sativum) cochleata (coch) mutants, which are characterized by the abnormal development of roots from the nodule, we identified the NOOT and COCH genes as being necessary for the robust maintenance of nodule identity throughout the nodule developmental program. NOOT and COCH are Arabidopsis thaliana BLADE-ON-PETIOLE orthologs, and we have shown that their functions in leaf and flower development are conserved in M. truncatula and pea. The identification of these two genes defines a clade in the BTB/POZ-ankyrin domain proteins that shares conserved functions in eudicot organ development and suggests that NOOT and COCH were recruited to repress root identity in the legume symbiotic organ. PMID:23136374

  7. Mixed Nodule Infection in Sinorhizobium meliloti–Medicago sativa Symbiosis Suggest the Presence of Cheating Behavior

    PubMed Central

    Checcucci, Alice; Azzarello, Elisa; Bazzicalupo, Marco; Galardini, Marco; Lagomarsino, Alessandra; Mancuso, Stefano; Marti, Lucia; Marzano, Maria C.; Mocali, Stefano; Squartini, Andrea; Zanardo, Marina; Mengoni, Alessio

    2016-01-01

    In the symbiosis between rhizobia and legumes, host plants can form symbiotic root nodules with multiple rhizobial strains, potentially showing different symbiotic performances in nitrogen fixation. Here, we investigated the presence of mixed nodules, containing rhizobia with different degrees of mutualisms, and evaluate their relative fitness in the Sinorhizobium meliloti–Medicago sativa model symbiosis. We used three S. meliloti strains, the mutualist strains Rm1021 and BL225C and the non-mutualist AK83. We performed competition experiments involving both in vitro and in vivo symbiotic assays with M. sativa host plants. We show the occurrence of a high number (from 27 to 100%) of mixed nodules with no negative effect on both nitrogen fixation and plant growth. The estimation of the relative fitness as non-mutualist/mutualist ratios in single nodules shows that in some nodules the non-mutualist strain efficiently colonized root nodules along with the mutualist ones. In conclusion, we can support the hypothesis that in S. meliloti–M. sativa symbiosis mixed nodules are formed and allow non-mutualist or less-mutualist bacterial partners to be less or not sanctioned by the host plant, hence allowing a potential form of cheating behavior to be present in the nitrogen fixing symbiosis. PMID:27379128

  8. Mixed Nodule Infection in Sinorhizobium meliloti-Medicago sativa Symbiosis Suggest the Presence of Cheating Behavior.

    PubMed

    Checcucci, Alice; Azzarello, Elisa; Bazzicalupo, Marco; Galardini, Marco; Lagomarsino, Alessandra; Mancuso, Stefano; Marti, Lucia; Marzano, Maria C; Mocali, Stefano; Squartini, Andrea; Zanardo, Marina; Mengoni, Alessio

    2016-01-01

    In the symbiosis between rhizobia and legumes, host plants can form symbiotic root nodules with multiple rhizobial strains, potentially showing different symbiotic performances in nitrogen fixation. Here, we investigated the presence of mixed nodules, containing rhizobia with different degrees of mutualisms, and evaluate their relative fitness in the Sinorhizobium meliloti-Medicago sativa model symbiosis. We used three S. meliloti strains, the mutualist strains Rm1021 and BL225C and the non-mutualist AK83. We performed competition experiments involving both in vitro and in vivo symbiotic assays with M. sativa host plants. We show the occurrence of a high number (from 27 to 100%) of mixed nodules with no negative effect on both nitrogen fixation and plant growth. The estimation of the relative fitness as non-mutualist/mutualist ratios in single nodules shows that in some nodules the non-mutualist strain efficiently colonized root nodules along with the mutualist ones. In conclusion, we can support the hypothesis that in S. meliloti-M. sativa symbiosis mixed nodules are formed and allow non-mutualist or less-mutualist bacterial partners to be less or not sanctioned by the host plant, hence allowing a potential form of cheating behavior to be present in the nitrogen fixing symbiosis. PMID:27379128

  9. Human selection and the relaxation of legume defences against ineffective rhizobia.

    PubMed

    Kiers, E Toby; Hutton, Mark G; Denison, R Ford

    2007-12-22

    Enforcement mechanisms are thought to be important in maintaining mutualistic cooperation between species. A clear example of an enforcement mechanism is how legumes impose sanctions on rhizobial symbionts that fail to provide sufficient fixed N2. However, with domestication and breeding in high-soil-N environments, humans may have altered these natural legume defences and reduced the agricultural benefits of the symbiosis. Using six genotypes of soya beans, representing 60 years of breeding, we show that, as a group, older cultivars were better able to maintain fitness than newer cultivars (seed production) when infected with a mixture of effective and ineffective rhizobial strains. Additionally, we found small differences among cultivars in the ratio of effective:ineffective rhizobia released from their nodules, an indicator of future rhizobial strain fitness. When infected by symbionts varying in quality, legume defences against poor-quality partners have apparently worsened under decades of artificial selection. PMID:17939985

  10. Nitrate Effects on Nodule Oxygen Permeability and Leghemoglobin (Nodule Oximetry and Computer Modeling).

    PubMed Central

    Denison, R. F.; Harter, B. L.

    1995-01-01

    Two current hypotheses to explain nitrate inhibition of nodule function both involve decreased O2 supply for respiration in support of N2 fixation. This decrease could result from either (a) decreased O2 permeability (PO) of the nodule cortex, or (b) conversion of leghemoglobin (Lb) to an inactive, nitrosyl form. These hypotheses were tested using alfalfa (Medicago sativa L. cv Weevlchek) and birdsfoot trefoil (Lotus corniculatus L. cv Fergus) plants grown in growth pouches under controlled conditions. Nodulated roots were exposed to 10 mM KNO3 or KCI. Fractional oxygenation of Lb under air (FOLair), relative concentration of functional Lb, apparent PO, and O2-saturated central zone respiration rate were all monitored by nodule oximetry. Apparent PO and FOLair in nitrate-treated nodules decreased to <50% of values for KCI controls within 24 h, but there was no decrease in functional Lb concentration during the first 72 h. In nitrate-treated alfalfa, but not in birdsfoot trefoil, FOLair, apparent PO, and O2-saturated central zone respiration rate decreased during each light period and recovered somewhat during the subsequent dark period. This species difference could be explained by greater reliance on photoreduction of nitrate in alfalfa than in birdsfoot trefoil. Computer simulations extended the experimental results, showing that previously reported decreases in apparent PO of Glycine max nodules with nitrate exposure cannot be explained by hypothetical decreases in the concentration or O2 affinity of Lb. PMID:12228439

  11. Assess suitability of hydroaeroponic culture to establish tripartite symbiosis between different AMF species, beans, and rhizobia

    PubMed Central

    Tajini, Fatma; Suriyakup, Porntip; Vailhe, Hélène; Jansa, Jan; Drevon, Jean-Jacques

    2009-01-01

    Background Like other species of the Phaseoleae tribe, common bean (Phaseolus vulgaris L.) has the potential to establish symbiosis with rhizobia and to fix the atmospheric dinitrogen (N2) for its N nutrition. Common bean has also the potential to establish symbiosis with arbuscular mycorrhizal fungi (AMF) that improves the uptake of low mobile nutrients such as phosphorus, from the soil. Both rhizobial and mycorrhizal symbioses can act synergistically in benefits on plant. Results The tripartite symbiosis of common bean with rhizobia and arbuscular mycorrhizal fungi (AMF) was assessed in hydroaeroponic culture with common bean (Phaseolus vulgaris L.), by comparing the effects of three fungi spp. on growth, nodulation and mycorrhization of the roots under sufficient versus deficient P supplies, after transfer from initial sand culture. Although Glomus intraradices Schenck & Smith colonized intensely the roots of common bean in both sand and hydroaeroponic cultures, Gigaspora rosea Nicolson & Schenck only established well under sand culture conditions, and no root-colonization was found with Acaulospora mellea Spain & Schenck under either culture conditions. Interestingly, mycorrhization by Glomus was also obtained by contact with mycorrhized Stylosanthes guianensis (Aubl.) sw in sand culture under deficient P before transfer into hydroaeroponic culture. The effect of bean genotype on both rhizobial and mycorrhizal symbioses with Glomus was subsequently assessed with the common bean recombinant inbreed line 7, 28, 83, 115 and 147, and the cultivar Flamingo. Significant differences among colonization and nodulation of the roots and growth among genotypes were found. Conclusion The hydroaeroponic culture is a valuable tool for further scrutinizing the physiological interactions and nutrient partitioning within the tripartite symbiosis. PMID:19534785

  12. Study of the basis for the competitiveness of Rhizobium japonicum in the nodulation of soybean

    SciTech Connect

    Bauer, W.

    1990-06-01

    The overall goal of our studies was to identify cellular and molecular characteristics of rhizobia that are important to root colonization and symbiotic infection in competition with indigenous soil microbes. Rhizobia were found to respond to specific host flavonoids as chemoattractants as well as nodulation gene inducers. Motility and chemotaxis contributed significantly to the efficiency of symbiotic interactions, but not to colonization of root tips, where bacterial dispersal depended primarily on passive movement by root cell elongation. Co-inoculation of Rhizobium nod gene mutants with each other and with the wild-type showed that the mutants could help the wild-type, but not each other, to initiate nodules. Mutants with defective host specificity genes were the only ones capable of helping the wild-type in an additive or synergistic manner. Alfalfa was shown to have rapid, systemic feedback regulation suppressing nodule formation in younger parts of the root system in response to initiation of the first nodules. Root mucilage and exudate components were found to affect attachment of rhizobia to root surfaces. Methods for optimal surface sterilization of legume seeds were examined. 5 refs.

  13. Cloning of Rhizobium leguminosarum genes for competitive nodulation blocking on peas.

    PubMed Central

    Dowling, D N; Samrey, U; Stanley, J; Broughton, W J

    1987-01-01

    One type of competitive interaction among rhizobia is that between nonnodulating and nodulating strains of Rhizobium leguminosarum on primitive pea genotypes. Pisum sativum cv. Afghanistan nodulates effectively with R. leguminosarum TOM, and this can be blocked in mixed inoculations by R. leguminosarum PF2, which does not nodulate this cultivar. We termed this PF2 phenotype Cnb+, for competitive nodulation blocking. Strain PF2 contains three large plasmids including a 250-kilobase-pair symbiotic (Sym) plasmid. Transfer of this plasmid, pSymPF2, to nonblocking rhizobia conferred the Cnb+ phenotype on recipients in mixed inoculations on cultivar Afghanistan with TOM. A library of the PF2 genome constructed in the vector pMMB33 was used to isolate two cosmid clones which hybridize to pSymPF2. These cosmids, pDD50 and pDD58, overlapped to the extent of 23 kilobase pairs and conferred a Cnb+ phenotype on recipient Cnb- rhizobia, as did pSD1, a subclone from the common region. Images PMID:3546272

  14. Ethylene, a Hormone at the Center-Stage of Nodulation.

    PubMed

    Guinel, Frédérique C

    2015-01-01

    Nodulation is the result of a beneficial interaction between legumes and rhizobia. It is a sophisticated process leading to nutrient exchange between the two types of symbionts. In this association, within a nodule, the rhizobia, using energy provided as photosynthates, fix atmospheric nitrogen and convert it to ammonium which is available to the plant. Nodulation is recognized as an essential process in nitrogen cycling and legume crops are known to enrich agricultural soils in nitrogenous compounds. Furthermore, as they are rich in nitrogen, legumes are considered important as staple foods for humans and fodder for animals. To tightly control this association and keep it mutualistic, the plant uses several means, including hormones. The hormone ethylene has been known as a negative regulator of nodulation for almost four decades. Since then, much progress has been made in the understanding of both the ethylene signaling pathway and the nodulation process. Here I have taken a large view, using recently obtained knowledge, to describe in some detail the major stages of the process. I have not only reviewed the steps most commonly covered (the common signaling transduction pathway, and the epidermal and cortical programs), but I have also looked into steps less understood (the pre-infection step with the plant defense response, the bacterial release and the formation of the symbiosome, and nodule functioning and senescence). After a succinct review of the ethylene signaling pathway, I have used the knowledge obtained from nodulation- and ethylene-related mutants to paint a more complete picture of the role played by the hormone in nodule organogenesis, functioning, and senescence. It transpires that ethylene is at the center of this effective symbiosis. It has not only been involved in most of the steps leading to a mature nodule, but it has also been implicated in host immunity and nodule senescence. It is likely responsible for the activation of other hormonal

  15. Ethylene, a Hormone at the Center-Stage of Nodulation

    PubMed Central

    Guinel, Frédérique C.

    2015-01-01

    Nodulation is the result of a beneficial interaction between legumes and rhizobia. It is a sophisticated process leading to nutrient exchange between the two types of symbionts. In this association, within a nodule, the rhizobia, using energy provided as photosynthates, fix atmospheric nitrogen and convert it to ammonium which is available to the plant. Nodulation is recognized as an essential process in nitrogen cycling and legume crops are known to enrich agricultural soils in nitrogenous compounds. Furthermore, as they are rich in nitrogen, legumes are considered important as staple foods for humans and fodder for animals. To tightly control this association and keep it mutualistic, the plant uses several means, including hormones. The hormone ethylene has been known as a negative regulator of nodulation for almost four decades. Since then, much progress has been made in the understanding of both the ethylene signaling pathway and the nodulation process. Here I have taken a large view, using recently obtained knowledge, to describe in some detail the major stages of the process. I have not only reviewed the steps most commonly covered (the common signaling transduction pathway, and the epidermal and cortical programs), but I have also looked into steps less understood (the pre-infection step with the plant defense response, the bacterial release and the formation of the symbiosome, and nodule functioning and senescence). After a succinct review of the ethylene signaling pathway, I have used the knowledge obtained from nodulation- and ethylene-related mutants to paint a more complete picture of the role played by the hormone in nodule organogenesis, functioning, and senescence. It transpires that ethylene is at the center of this effective symbiosis. It has not only been involved in most of the steps leading to a mature nodule, but it has also been implicated in host immunity and nodule senescence. It is likely responsible for the activation of other hormonal

  16. Efficiency of partner choice and sanctions in Lotus is not altered by nitrogen fertilization.

    PubMed

    Regus, John U; Gano, Kelsey A; Hollowell, Amanda C; Sachs, Joel L

    2014-04-22

    Eukaryotic hosts must exhibit control mechanisms to select against ineffective bacterial symbionts. Hosts can minimize infection by less-effective symbionts (partner choice) and can divest of uncooperative bacteria after infection (sanctions). Yet, such host-control traits are predicted to be context dependent, especially if they are costly for hosts to express or maintain. Legumes form symbiosis with rhizobia that vary in symbiotic effectiveness (nitrogen fixation) and can enforce partner choice as well as sanctions. In nature, legumes acquire fixed nitrogen from both rhizobia and soils, and nitrogen deposition is rapidly enriching soils globally. If soil nitrogen is abundant, we predict host control to be downregulated, potentially allowing invasion of ineffective symbionts. We experimentally manipulated soil nitrogen to examine context dependence in host control. We co-inoculated Lotus strigosus from nitrogen depauperate soils with pairs of Bradyrhizobium strains that vary in symbiotic effectiveness and fertilized plants with either zero nitrogen or growth maximizing nitrogen. We found efficient partner choice and sanctions regardless of nitrogen fertilization, symbiotic partner combination or growth season. Strikingly, host control was efficient even when L. strigosus gained no significant benefit from rhizobial infection, suggesting that these traits are resilient to short-term changes in extrinsic nitrogen, whether natural or anthropogenic. PMID:24573843

  17. Efficiency of partner choice and sanctions in Lotus is not altered by nitrogen fertilization

    PubMed Central

    Regus, John U.; Gano, Kelsey A.; Hollowell, Amanda C.; Sachs, Joel L.

    2014-01-01

    Eukaryotic hosts must exhibit control mechanisms to select against ineffective bacterial symbionts. Hosts can minimize infection by less-effective symbionts (partner choice) and can divest of uncooperative bacteria after infection (sanctions). Yet, such host-control traits are predicted to be context dependent, especially if they are costly for hosts to express or maintain. Legumes form symbiosis with rhizobia that vary in symbiotic effectiveness (nitrogen fixation) and can enforce partner choice as well as sanctions. In nature, legumes acquire fixed nitrogen from both rhizobia and soils, and nitrogen deposition is rapidly enriching soils globally. If soil nitrogen is abundant, we predict host control to be downregulated, potentially allowing invasion of ineffective symbionts. We experimentally manipulated soil nitrogen to examine context dependence in host control. We co-inoculated Lotus strigosus from nitrogen depauperate soils with pairs of Bradyrhizobium strains that vary in symbiotic effectiveness and fertilized plants with either zero nitrogen or growth maximizing nitrogen. We found efficient partner choice and sanctions regardless of nitrogen fertilization, symbiotic partner combination or growth season. Strikingly, host control was efficient even when L. strigosus gained no significant benefit from rhizobial infection, suggesting that these traits are resilient to short-term changes in extrinsic nitrogen, whether natural or anthropogenic. PMID:24573843

  18. nip, a Symbiotic Medicago truncatula Mutant That Forms Root Nodules with Aberrant Infection Threads and Plant Defense-Like Response1

    PubMed Central

    Veereshlingam, Harita; Haynes, Janine G.; Penmetsa, R. Varma; Cook, Douglas R.; Sherrier, D. Janine; Dickstein, Rebecca

    2004-01-01

    To investigate the legume-Rhizobium symbiosis, we isolated and studied a novel symbiotic mutant of the model legume Medicago truncatula, designated nip (numerous infections and polyphenolics). When grown on nitrogen-free media in the presence of the compatible bacterium Sinorhizobium meliloti, the nip mutant showed nitrogen deficiency symptoms. The mutant failed to form pink nitrogen-fixing nodules that occur in the wild-type symbiosis, but instead developed small bump-like nodules on its roots that were blocked at an early stage of development. Examination of the nip nodules by light microscopy after staining with X-Gal for S. meliloti expressing a constitutive GUS gene, by confocal microscopy following staining with SYTO-13, and by electron microscopy revealed that nip initiated symbiotic interactions and formed nodule primordia and infection threads. The infection threads in nip proliferated abnormally and very rarely deposited rhizobia into plant host cells; rhizobia failed to differentiate further in these cases. nip nodules contained autofluorescent cells and accumulated a brown pigment. Histochemical staining of nip nodules revealed this pigment to be polyphenolic accumulation. RNA blot analyses demonstrated that nip nodules expressed only a subset of genes associated with nodule organogenesis, as well as elevated expression of a host defense-associated phenylalanine ammonia lyase gene. nip plants were observed to have abnormal lateral roots. nip plant root growth and nodulation responded normally to ethylene inhibitors and precursors. Allelism tests showed that nip complements 14 other M. truncatula nodulation mutants but not latd, a mutant with a more severe nodulation phenotype as well as primary and lateral root defects. Thus, the nip mutant defines a new locus, NIP, required for appropriate infection thread development during invasion of the nascent nodule by rhizobia, normal lateral root elongation, and normal regulation of host defense-like responses

  19. Basis for the competitiveness of Rhizobium japonicum in nodulation of soybean. Final progress report

    SciTech Connect

    Evans, W.R.; Bauer, W.D.

    1986-07-30

    This study sought to identify molecular, genetic and environmental factors most crucial to the ability of an inoculated strain of rhizobia to nodulate soybean roots in the face of competition from indigenous microorganisms. Co-inoculation of a more efficient strain with a less-efficient strain resulted in the more efficient strain occupying a higher percentage of nodules. When culture conditions became less stringent the less efficient strain became more competitive. The number of infections formed was related in a direct manner to nodulation efficiency. The strain which was more nodulation efficient also was more infection efficient. That the number of infections per se, as determined in a single inoculum, can not be the only factor in determining the competency was indicated by experiments in which one strain formed more total infection yet nodule occupancy was equally distributed. 5 figs., 9 tabs.

  20. Methylotrophic Methylobacterium Bacteria Nodulate and Fix Nitrogen in Symbiosis with Legumes

    PubMed Central

    Sy, Abdoulaye; Giraud, Eric; Jourand, Philippe; Garcia, Nelly; Willems, Anne; de Lajudie, Philippe; Prin, Yves; Neyra, Marc; Gillis, Monique; Boivin-Masson, Catherine; Dreyfus, Bernard

    2001-01-01

    Rhizobia described so far belong to three distinct phylogenetic branches within the α-2 subclass of Proteobacteria. Here we report the discovery of a fourth rhizobial branch involving bacteria of the Methylobacterium genus. Rhizobia isolated from Crotalaria legumes were assigned to a new species, “Methylobacterium nodulans,” within the Methylobacterium genus on the basis of 16S ribosomal DNA analyses. We demonstrated that these rhizobia facultatively grow on methanol, which is a characteristic of Methylobacterium spp. but a unique feature among rhizobia. Genes encoding two key enzymes of methylotrophy and nodulation, the mxaF gene, encoding the α subunit of the methanol dehydrogenase, and the nodA gene, encoding an acyltransferase involved in Nod factor biosynthesis, were sequenced for the type strain, ORS2060. Plant tests and nodA amplification assays showed that “M. nodulans” is the only nodulating Methylobacterium sp. identified so far. Phylogenetic sequence analysis showed that “M. nodulans” NodA is closely related to Bradyrhizobium NodA, suggesting that this gene was acquired by horizontal gene transfer. PMID:11114919

  1. A Legume Genetic Framework Controls Infection of Nodules by Symbiotic and Endophytic Bacteria

    PubMed Central

    Zgadzaj, Rafal; James, Euan K.; Kelly, Simon; Kawaharada, Yasuyuki; de Jonge, Nadieh; Jensen, Dorthe B.; Madsen, Lene H.; Radutoiu, Simona

    2015-01-01

    Legumes have an intrinsic capacity to accommodate both symbiotic and endophytic bacteria within root nodules. For the symbionts, a complex genetic mechanism that allows mutual recognition and plant infection has emerged from genetic studies under axenic conditions. In contrast, little is known about the mechanisms controlling the endophytic infection. Here we investigate the contribution of both the host and the symbiotic microbe to endophyte infection and development of mixed colonised nodules in Lotus japonicus. We found that infection threads initiated by Mesorhizobium loti, the natural symbiont of Lotus, can selectively guide endophytic bacteria towards nodule primordia, where competent strains multiply and colonise the nodule together with the nitrogen-fixing symbiotic partner. Further co-inoculation studies with the competent coloniser, Rhizobium mesosinicum strain KAW12, show that endophytic nodule infection depends on functional and efficient M. loti-driven Nod factor signalling. KAW12 exopolysaccharide (EPS) enabled endophyte nodule infection whilst compatible M. loti EPS restricted it. Analysis of plant mutants that control different stages of the symbiotic infection showed that both symbiont and endophyte accommodation within nodules is under host genetic control. This demonstrates that when legume plants are exposed to complex communities they selectively regulate access and accommodation of bacteria occupying this specialized environmental niche, the root nodule. PMID:26042417

  2. GS52 Ecto-Apyrase Plays a Critical Role during Soybean Nodulation1[W][OA

    PubMed Central

    Govindarajulu, Manjula; Kim, Sung-Yong; Libault, Marc; Berg, R. Howard; Tanaka, Kiwamu; Stacey, Gary; Taylor, Christopher G.

    2009-01-01

    Apyrases are non-energy-coupled nucleotide phosphohydrolases that hydrolyze nucleoside triphosphates and nucleoside diphosphates to nucleoside monophosphates and orthophosphates. GS52, a soybean (Glycine soja) ecto-apyrase, was previously shown to be induced very early in response to inoculation with the symbiotic bacterium Bradyrhizobium japonicum. Overexpression of the GS52 ecto-apyrase in Lotus japonicus increased the level of rhizobial infection and enhanced nodulation. These data suggest a critical role for the GS52 ecto-apyrase during nodulation. To further investigate the role of GS52 during nodulation, we used RNA interference to silence GS52 expression in soybean (Glycine max) roots using Agrobacterium rhizogenes-mediated root transformation. Transcript levels of GS52 were significantly reduced in GS52 silenced roots and these roots exhibited reduced numbers of mature nodules. Development of the nodule primordium and subsequent nodule maturation was significantly suppressed in GS52 silenced roots. Transmission electron micrographs of GS52 silenced root nodules showed that early senescence and infected cortical cells were devoid of symbiosome-containing bacteroids. Application of exogenous adenosine diphosphate to silenced GS52 roots restored nodule development. Restored nodules contained bacteroids, thus indicating that extracellular adenosine diphosphate is important during nodulation. These results clearly suggest that GS52 ecto-apyrase catalytic activity is critical for the early B. japonicum infection process, initiation of nodule primordium development, and subsequent nodule organogenesis in soybean. PMID:19036836

  3. VAMP721a and VAMP721d are important for pectin dynamics and release of bacteria in soybean nodules.

    PubMed

    Gavrin, Aleksandr; Chiasson, David; Ovchinnikova, Evgenia; Kaiser, Brent N; Bisseling, Ton; Fedorova, Elena E

    2016-05-01

    In root nodules rhizobia enter host cells via infection threads. The release of bacteria to a host cell is possible from cell wall-free regions of the infection thread. We hypothesized that the VAMP721d and VAMP721e exocytotic pathway, identified before in Medicago truncatula, has a role in the local modification of cell wall during the release of rhizobia. To clarify the role of VAMP721d and VAMP721e we used Glycine max, a plant with a determinate type of nodule. The localization of the main polysaccharide compounds of primary cell walls was analysed in control vs nodules with partially silenced GmVAMP721d. The silencing of GmVAMP721d blocked the release of rhizobia. Instead of rhizobia-containing membrane compartments - symbiosomes - the infected cells contained big clusters of bacteria embedded in a matrix of methyl-esterified and de-methyl-esterified pectin. These clusters were surrounded by a membrane. We found that GmVAMP721d-positive vesicles were not transporting methyl-esterified pectin. We hypothesized that they may deliver the enzymes involved in pectin turnover. Subsequently, we found that GmVAMP721d is partly co-localized with pectate lyase. Therefore, the biological role of VAMP721d may be explained by its action in delivering pectin-modifying enzymes to the site of release. PMID:26790563

  4. Nitrate inhibition of legume nodule growth and activity. II. Short term studies with high nitrate supply

    SciTech Connect

    Streeter, J.G.

    1985-02-01

    Soybean plants (Glycine max (L.) Merr) were grown in sand culture with 2 millimolar nitrate for 37 days and then supplied with 15 millimolar nitrate for 7 days. Control plants received 2 millimolar nitrate and 13 millimolar chloride and, after the 7-day treatment period, all plants were supplied with nil nitrate. The temporary treatment with high nitrate inhibited nitrogenase (acetylene reduction) activity by 80% whether or not Rhizobium japonicum bacteroids had nitrate reductase (NR) activity. The pattern of nitrite accumulation in nodules formed by NR/sup +/ rhizobia was inversely related to the decrease and recovery of nitrogenase activity. However, nitrite concentration in nodules formed by NR/sup -/ rhizobia appeared to be too low to explain the inhibition of nitrogenase. Nodules on plants treated with 15 millimolar nitrate contained higher concentrations of amino N and, especially, ureide N than control nodules and, after withdrawal of nitrate, reduced N content of treated and control nodules returned to similar levels. The accumulation of N/sub 2/ fixation products in nodules in response to high nitrate treatment was observed with three R. japonicum strains, two NR/sup +/ and one NR/sup -/.

  5. Drought Stress Responses in Soybean Roots and Nodules.

    PubMed

    Kunert, Karl J; Vorster, Barend J; Fenta, Berhanu A; Kibido, Tsholofelo; Dionisio, Giuseppe; Foyer, Christine H

    2016-01-01

    Drought is considered to be a major threat to soybean production worldwide and yet our current understanding of the effects of drought on soybean productively is largely based on studies on above-ground traits. Although the roots and root nodules are important sensors of drought, the responses of these crucial organs and their drought tolerance features remain poorly characterized. The symbiotic interaction between soybean and rhizobia facilitates atmospheric nitrogen fixation, a process that provides essential nitrogen to support plant growth and development. Symbiotic nitrogen fixation is important for sustainable agriculture, as it sustains plant growth on nitrogen-poor soils and limits fertilizer use for crop nitrogen nutrition. Recent developments have been made in our understanding of the drought impact on soybean root architecture and nodule traits, as well as underpinning transcriptome, proteome and also emerging metabolome information, with a view to improve the selection of more drought-tolerant soybean cultivars and rhizobia in the future. We conclude that the direct screening of root and nodule traits in the field as well as identification of genes, proteins and also metabolites involved in such traits will be essential in order to gain a better understanding of the regulation of root architecture, bacteroid development and lifespan in relation to drought tolerance in soybean. PMID:27462339

  6. Drought Stress Responses in Soybean Roots and Nodules

    PubMed Central

    Kunert, Karl J.; Vorster, Barend J.; Fenta, Berhanu A.; Kibido, Tsholofelo; Dionisio, Giuseppe; Foyer, Christine H.

    2016-01-01

    Drought is considered to be a major threat to soybean production worldwide and yet our current understanding of the effects of drought on soybean productively is largely based on studies on above-ground traits. Although the roots and root nodules are important sensors of drought, the responses of these crucial organs and their drought tolerance features remain poorly characterized. The symbiotic interaction between soybean and rhizobia facilitates atmospheric nitrogen fixation, a process that provides essential nitrogen to support plant growth and development. Symbiotic nitrogen fixation is important for sustainable agriculture, as it sustains plant growth on nitrogen-poor soils and limits fertilizer use for crop nitrogen nutrition. Recent developments have been made in our understanding of the drought impact on soybean root architecture and nodule traits, as well as underpinning transcriptome, proteome and also emerging metabolome information, with a view to improve the selection of more drought-tolerant soybean cultivars and rhizobia in the future. We conclude that the direct screening of root and nodule traits in the field as well as identification of genes, proteins and also metabolites involved in such traits will be essential in order to gain a better understanding of the regulation of root architecture, bacteroid development and lifespan in relation to drought tolerance in soybean. PMID:27462339

  7. (Study of the basis for the competitiveness of Rhizobium japonicum in the nodulation of soybean): Progress report, (May 1986-May 1987)

    SciTech Connect

    Bauer, W.D.

    1987-01-01

    The overall goal of our current studies is to identify cellular and molecular factors that are of central importance to the colonization and infection of host roots by inoculated rhizobia in competition with indigenous soil microbes. This report covers research compelted between May 1986 and May 1987. Progress was made during the past year in areas of the role of motility and chemotaxis in nodule initiation by rhizobia, the further characterization of bacterial adhesion to host root surfaces, the effects of root exudate on bacterial attachment, the effects of bacteria and bacterial culture filtrates on bacterial attachment, the movement of rhizobia on the surface of the growing host root, and the effects of adding various nod mutants of Rhizobium meliloti on nodule formation by co-inoculated wildtype cells. 1 fig., 5 tabs.

  8. Thyroid nodules.

    PubMed

    Niedziela, Marek

    2014-03-01

    According to the literature, thyroid nodules (TNs) are quite rare in the first two decades of life and are predominantly non-cancerous, although cancerous TNs are more common in the first two decades of life than in adults. Therefore, it is important for clinicians to distinguish benign from malignant lesions preoperatively because the latter require a total thyroidectomy with or without neck lymph node dissection. A careful work-up and a fine-needle aspiration biopsy (FNAB) are mandatory to improve the preoperative diagnosis. High-resolution thyroid ultrasound and real-time elastosonography are adjuvant presurgical tools in selecting patients for surgery, particularly those with indeterminate or non-diagnostic cytology. Elevated thyroid-stimulating hormone (TSH) level in a patient with a thyroid nodule is a new laboratory predictor of thyroid cancer risk. The majority of thyroid carcinomas derive from the follicular cell, whereas medullary thyroid carcinoma (MTC) derives from calcitonin-producing cells. Patients with MTC are screened for germ-line RET mutations to detect carriers and identify family members for prophylactic or therapeutic thyroidectomy. PMID:24629865

  9. Nodulation of Cyclopia spp. (Leguminosae, Papilionoideae) by Burkholderia tuberum

    PubMed Central

    Elliott, Geoffrey N.; Chen, Wen-Ming; Bontemps, Cyril; Chou, Jui-Hsing; Young, J. Peter W.; Sprent, Janet I.; James, Euan K.

    2007-01-01

    nodulate papilioinoid legumes. Conclusions Papilionoid legumes from widely different tribes can be nodulated by β-rhizobia, forming both indeterminate (Cyclopia) and determinate (Macroptilium) nodules. PMID:17881339

  10. Gene expression and localization of a β-1,3-glucanase of Lotus japonicus.

    PubMed

    Osuki, Ken-Ichi; Hashimoto, Shun; Suzuki, Akihiro; Araragi, Masato; Takahara, Akihito; Kurosawa, Makiko; Kucho, Ken-Ichi; Higashi, Shiro; Abe, Mikiko; Uchiumi, Toshiki

    2016-07-01

    Phytohormone abscisic acid (ABA) inhibits root nodule formation of leguminous plants. LjGlu1, a β-1,3-glucanase gene of Lotus japonicus, has been identified as an ABA responsive gene. RNA interference of LjGlu1 increased nodule number. This suggests that LjGlu1 is involved in the regulation of nodule formation. Host legumes control nodule number by autoregulation of nodulation (AON), in which the presence of existing root nodules inhibits further nodulation. For further characterization of LjGlu1, we focused on the expression of LjGlu1 in relation to AON. In a split-root system, LjGlu1 expression peaked when AON was fully induced. Hairy roots transformed with LjCLE-RS1, a gene that induces AON, were generated. Expression of LjGlu1 was greater in the transgenic roots than in untransformed roots. LjGlu1 was not induced in a hypernodulating mutant inoculated with Mesorhizobium loti. These results suggest that the expression of LjGlu1 is involved in the system of AON. However, neither hypernodulation nor enlarged nodulation zone was observed on the transgenic hairy roots carrying LjGlu1-RNAi, suggesting that LjGlu1 is not a key player of AON. Recombinant LjGlu1 showed endo-β-1,3-glucanase activity. LjGlu1-mOrange fusion protein suggested that LjGlu1 associated with M. loti on the root hairs. Exogenous β-1,3-glucanase inhibited infection thread formation by both the wild type and the mutant, and nodule numbers were reduced. These results suggest that LjGlu1 is expressed in response to M. loti infection and functions outside root tissues, resulting in the inhibition of infection. PMID:26951113

  11. Efficient Inactivation of Symbiotic Nitrogen Fixation Related Genes in Lotus japonicus Using CRISPR-Cas9

    PubMed Central

    Wang, Longxiang; Wang, Longlong; Tan, Qian; Fan, Qiuling; Zhu, Hui; Hong, Zonglie; Zhang, Zhongming; Duanmu, Deqiang

    2016-01-01

    The targeted genome editing technique, CRISPR/Cas9 system, has been widely used to modify genes of interest in a predictable and precise manner. In this study, we describe the CRISPR/Cas9-mediated efficient editing of representative SNF (symbiotic nitrogen fixation) related genes in the model legume Lotus japonicus via Agrobacterium-mediated stable or hairy root transformation. We first predicted nine endogenous U6 genes in Lotus and then demonstrated the efficacy of the LjU6-1 gene promoter in driving expression of single guide RNAs (sgRNAs) by using a split yellow fluorescence protein (YFP) reporter system to restore the fluorescence in Arabidopsis protoplasts. Next, we chose a customized sgRNA targeting SYMRK (symbiosis receptor-like kinase) loci and achieved ~35% mutagenic efficiency in 20 T0 transgenic plants, two of them containing biallelic homozygous mutations with a 2-bp deletion near the PAM region. We further designed two sgRNAs targeting three homologous leghemoglobin loci (LjLb1, LjLb2, LjLb3) for testing the possibility of generating multi-gene knockouts. 20 out of 70 hairy root transgenic plants exhibited white nodules, with at least two LjLbs disrupted in each plant. Compared with the constitutively active CaMV 35S promoter, the nodule-specific LjLb2 promoter was also effective in gene editing in nodules by hairy root transformation. Triple mutant knockout of LjLbs was also obtained by stable transformation using two sgRNAs. Collectively, these studies demonstrate that the CRISPR/Cas9 system should greatly facilitate functional analyses of SNF related genes in Lotus japonicus.

  12. Negotiation of mutualism: rhizobia and legumes

    PubMed Central

    Akçay, Erol; Roughgarden, Joan

    2006-01-01

    The evolution and persistence of biological cooperation have been an important puzzle in evolutionary theory. Here, we suggest a new approach based on bargaining theory to tackle the question. We present a mechanistic model for negotiation of benefits between a nitrogen-fixing nodule and a legume plant. To that end, we first derive growth rates for the nodule and plant from metabolic models of each as a function of material fluxes between them. We use these growth rates as pay-off functions in the negotiation process, which is analogous to collective bargaining between a firm and a workers' union. Our model predicts that negotiations lead to the Nash bargaining solution, maximizing the product of players' pay-offs. This work introduces elements of cooperative game theory into the field of mutualistic interactions. In the discussion of the paper, we argue for the benefits of such an approach in studying the question of biological cooperation. PMID:17015340

  13. A purple acid phosphatase plays a role in nodule formation and nitrogen fixation in Astragalus sinicus.

    PubMed

    Wang, Jianyun; Si, Zaiyong; Li, Fang; Xiong, Xiaobo; Lei, Lei; Xie, Fuli; Chen, Dasong; Li, Yixing; Li, Youguo

    2015-08-01

    The AsPPD1 gene from Astragalus sinicus encodes a purple acid phosphatase. To address the functions of AsPPD1 in legume-rhizobium symbiosis, its expression patterns, enzyme activity, subcellular localization, and phenotypes associated with its over-expression and RNA interference (RNAi) were investigated. The expression of AsPPD1 was up-regulated in roots and nodules after inoculation with rhizobia. Phosphate starvation reduced the levels of AsPPD1 transcripts in roots while increased those levels in nodules. We confirmed the acid phosphatase and phosphodiesterase activities of recombinant AsPPD1 purified from Pichia pastoris, and demonstrated its ability to hydrolyze ADP and ATP in vitro. Subcellular localization showed that AsPPD1 located on the plasma membranes in hairy roots and on the symbiosomes membranes in root nodules. Over-expression of AsPPD1 in hairy roots inhibited nodulation, while its silencing resulted in nodules early senescence and significantly decreased nitrogenase activity. Furthermore, HPLC measurement showed that AsPPD1 overexpression affects the ADP levels in the infected roots and nodules, AsPPD1 silencing affects the ratio of ATP/ADP and the energy charge in nodules, and quantitative observation demonstrated the changes of AsPPD1 transcripts level affected nodule primordia formation. Taken together, it is speculated that AsPPD1 contributes to symbiotic ADP levels and energy charge control, and this is required for effective nodule organogenesis and nitrogen fixation. PMID:26105827

  14. Root nodule bacteria from Clitoria ternatea L. are putative invasive nonrhizobial endophytes.

    PubMed

    Aeron, Abhinav; Chauhan, Puneet Singh; Dubey, Ramesh Chand; Maheshwari, Dinesh Kumar; Bajpai, Vivek K

    2015-02-01

    In this study, bacteria (8 species and 5 genera) belonging to the classes Betaproteobacteria, Gammaproteobacteria, and Sphingobacteria were isolated from root nodules of the multipurpose legume Clitoria ternatea L. and identified on the basis of partial 16S rRNA sequencing. The root nodule bacteria were subjected to phenotypic clustering and diversity studies using biochemical kits, including Hi-Media Carbokit™, Enterobacteriaceae™ identification kit, ERIC-PCR, and 16S ARDRA. All the strains showed growth on Ashby's N-free media over 7 generations, indicative of presumptive nitrogen fixation and further confirmed by amplification of the nifH gene. None of the strains showed the capability to renodulate the host plant, neither alone nor in combination with standard rhizobial strains, which was further confirmed by the absence of nodC bands in PCR assay. The results clearly indicate the common existence of nonrhizobial microflora inside the root nodules of legumes, which were thought to be colonized only by rhizobia and were responsible for N2 fixation in leguminous crops. However, with the recent discovery of nodule endophytes from a variety of legumes, as also observed here, it can be assumed that symbiotic rhizobia are not all alone and that these invasive endophytes belonging to various bacterial genera are more than just opportunistic colonizers of specialized nodule niche. PMID:25619106

  15. Relationship between photosynthetic capacity, nitrogen assimilation and nodule metabolism in alfalfa (Medicago sativa) grown with sewage sludge.

    PubMed

    Antolín, M Carmen; Fiasconaro, M Laura; Sánchez-Díaz, Manuel

    2010-10-15

    Sewage sludge has been used as N fertilizer because it contains some of inorganic N, principally as nitrate and ammonium ions. However, sewage sludge addition to legumes could result in impaired nodule metabolism due to the presence of inorganic N from sludge. A greenhouse experiment was conducted to examine the effects of sewage sludge on growth, photosynthesis, nitrogen assimilation and nodule metabolism in alfalfa (Medicago sativa L. cv. Aragón). Plants were grown in pots with a mixture of perlite and vermiculite (2:1, v/v). The experiment included three treatments: (1) plants inoculated with rhizobia and amended with sewage sludge at rate of 10% (w/w) (RS); (2) plants inoculated with rhizobia without any amendment (R); and (3) non-inoculated plants fed with ammonium nitrate (N). N(2)-fixing plants had lower growth and sucrose phosphate synthase activity but higher photosynthesis than nitrate-fed plants because they compensated the carbon cost of the rhizobia. However, sewage sludge-treated plants evidenced a loss of carbon sink strength due to N(2) fixation by means of decreased photosynthetic capacity, leaf chlorophylls and N concentration in comparison to untreated plants. Sewage sludge did no affect nodulation but decreased nodule enzyme activities involved in carbon and N metabolisms that may lead to accumulation of toxic N-compounds. PMID:20591568

  16. Diverse novel mesorhizobia nodulate New Zealand native Sophora species.

    PubMed

    Tan, Heng Wee; Heenan, Peter B; De Meyer, Sofie E; Willems, Anne; Andrews, Mitchell

    2015-03-01

    Forty eight rhizobial isolates from New Zealand (NZ) native Sophora spp. growing in natural ecosystems were characterised. Thirty eight isolates across five groups showed greatest similarity to Mesorhizobium ciceri LMG 14989(T) with respect to their 16S rRNA and concatenated recA, glnll and rpoB sequences. Seven isolates had a 16S rRNA sequence identical to M. amorphae ATCC 19665(T) but showed greatest similarity to M. septentrionale LMG 23930(T) on their concatenated recA, glnll and rpoB sequences. All isolates grouped closely together for their nifH, nodA and nodC sequences, clearly separate from all other rhizobia in the GenBank database. None of the type strains closest to the Sophora isolates based on 16S rRNA sequence similarity nodulated Sophora microphylla but they all nodulated their original host. Twenty one Sophora isolates selected from the different 16S rRNA groupings produced N2-fixing nodules on three Sophora spp. but none nodulated any host of the type strains for the related species. DNA hybridisations indicated that these isolates belong to novel Mesorhizobium spp. that nodulate NZ native Sophora species. PMID:25498849

  17. Novel, highly expressed late nodulin gene (LjNOD16) from Lotus japonicus

    SciTech Connect

    Kapranov, P.; Bruijn, F.J. de; Szczyglowski, K.

    1997-04-01

    We have isolated a Lotus japonicus cDNA corresponding to a highly abundant, late nodule-specific RNA species that encodes a polypeptide with a predicted molecular mass of 15.6 kD. The protein and its corresponding gene were designated NIj16 and LjNOD16, respectively. LjNOD16 was found to be expressed only in the infected cells of L. japonicus nodules. Related DNA sequences could be identified in the genomes of both Glycine max and Medicago sativa. In the latter, a homologous mRNA species was detected in the nodules. Unlike LiNOD16, its alfalfa homologs appear to represent low-abundance mRNA species. However, the proteins corresponding to the LjNOD16 and its alfalfa homolog could be detected at similar levels in nodules but not in roots of both legume species. The predicted amino acid sequence analysis of nodulin NIj16 revealed the presence of a long {alpha}-helical region and a positively charged C terminus. The former domain has a very high propensity to form a coiled-coil type structure, indicating that nodulin NIj16 may interact with an as-yet-unidentified protein target(s) in the nodule-infected cells. Homology searches revealed no significant similarities to any known sequences in the databases, with the exception of two related, anonymous Arabidopsis expressed sequence tags.

  18. South African Papilionoid Legumes Are Nodulated by Diverse Burkholderia with Unique Nodulation and Nitrogen-Fixation Loci

    PubMed Central

    Beukes, Chrizelle W.; Venter, Stephanus N.; Law, Ian J.; Phalane, Francina L.; Steenkamp, Emma T.

    2013-01-01

    The root-nodule bacteria of legumes endemic to the Cape Floristic Region are largely understudied, even though recent reports suggest the occurrence of nodulating Burkholderia species unique to the region. In this study, we considered the diversity and evolution of nodulating Burkholderia associated with the endemic papilionoid tribes Hypocalypteae and Podalyrieae. We identified distinct groups from verified rhizobial isolates by phylogenetic analyses of the 16S rRNA and recA housekeeping gene regions. In order to gain insight into the evolution of the nodulation and diazotrophy of these rhizobia we analysed the genes encoding NifH and NodA. The majority of these 69 isolates appeared to be unique, potentially representing novel species. Evidence of horizontal gene transfer determining the symbiotic ability of these Cape Floristic Region isolates indicate evolutionary origins distinct from those of nodulating Burkholderia from elsewhere in the world. Overall, our findings suggest that Burkholderia species associated with fynbos legumes are highly diverse and their symbiotic abilities have unique ancestries. It is therefore possible that the evolution of these bacteria is closely linked to the diversification and establishment of legumes characteristic of the Cape Floristic Region. PMID:23874611

  19. microRNA160 dictates stage-specific auxin and cytokinin sensitivities and directs soybean nodule development.

    PubMed

    Nizampatnam, Narasimha Rao; Schreier, Spencer John; Damodaran, Suresh; Adhikari, Sajag; Subramanian, Senthil

    2015-10-01

    Legume nodules result from coordinated interactions between the plant and nitrogen-fixing rhizobia. The phytohormone cytokinin promotes nodule formation, and recent findings suggest that the phytohormone auxin inhibits nodule formation. Here we show that microRNA160 (miR160) is a key signaling element that determines the auxin/cytokinin balance during nodule development in soybean (Glycine max). miR160 appears to promote auxin activity by suppressing the levels of the ARF10/16/17 family of repressor ARF transcription factors. Using quantitative PCR assays and a fluorescence miRNA sensor, we show that miR160 levels are relatively low early during nodule formation and high in mature nodules. We had previously shown that ectopic expression of miR160 in soybean roots led to a severe reduction in nodule formation, coupled with enhanced sensitivity to auxin and reduced sensitivity to cytokinin. Here we show that exogenous cytokinin restores nodule formation in miR160 over-expressing roots. Therefore, low miR160 levels early during nodule development favor cytokinin activity required for nodule formation. Suppression of miR160 levels using a short tandem target mimic (STTM160) resulted in reduced sensitivity to auxin and enhanced sensitivity to cytokinin. In contrast to miR160 over-expressing roots, STTM160 roots had increased nodule formation, but nodule maturation was significantly delayed. Exogenous auxin partially restored proper nodule formation and maturation in STTM160 roots, suggesting that high miR160 activity later during nodule development favors auxin activity and promotes nodule maturation. Therefore, miR160 dictates developmental stage-specific sensitivities to auxin and cytokinin to direct proper nodule formation and maturation in soybean. PMID:26287653

  20. A Sinorhizobium meliloti-specific N-acyl homoserine lactone quorum-sensing signal increases nodule numbers in Medicago truncatula independent of autoregulation

    PubMed Central

    Veliz-Vallejos, Debora F.; van Noorden, Giel E.; Yuan, Mengqi; Mathesius, Ulrike

    2014-01-01

    N-acyl homoserine lactones (AHLs) act as quorum sensing signals that regulate cell-density dependent behaviors in many gram-negative bacteria, in particular those important for plant-microbe interactions. AHLs can also be recognized by plants, and this may influence their interactions with bacteria. Here we tested whether the exposure to AHLs affects the nodule-forming symbiosis between legume hosts and rhizobia. We treated roots of the model legume, Medicago truncatula, with a range of AHLs either from its specific symbiont, Sinorhizobium meliloti, or from the potential pathogens, Pseudomonas aeruginosa and Agrobacterium vitis. We found increased numbers of nodules formed on root systems treated with the S. meliloti-specific AHL, 3-oxo-C14-homoserine lactone, at a concentration of 1 μM, while the other AHLs did not result in significant changes to nodule numbers. We did not find any evidence for altered nodule invasion by the rhizobia. Quantification of flavonoids that could act as nod gene inducers in S. meliloti did not show any correlation with increased nodule numbers. The effects of AHLs were specific for an increase in nodule numbers, but not lateral root numbers or root length. Increased nodule numbers following 3-oxo-C14-homoserine lactone treatment were under control of autoregulation of nodulation and were still observed in the autoregulation mutant, sunn4 (super numeric nodules4). However, increases in nodule numbers by 3-oxo-C14-homoserine lactone were not found in the ethylene-insensitive sickle mutant. A comparison between M. truncatula with M. sativa (alfalfa) and Trifolium repens (white clover) showed that the observed effects of AHLs on nodule numbers were specific to M. truncatula, despite M. sativa nodulating with the same symbiont. We conclude that plant perception of the S. meliloti-specific 3-oxo-C14-homoserine lactone influences nodule numbers in M. truncatula via an ethylene-dependent, but autoregulation-independent mechanism. PMID

  1. Polyphenol oxidase affects normal nodule development in red clover (Trifolium pratense L.)

    PubMed Central

    Webb, K. Judith; Cookson, Alan; Allison, Gordon; Sullivan, Michael L.; Winters, Ana L.

    2014-01-01

    Polyphenol oxidase (PPO) may have multiple functions in tissues depending on its cellular or tissue localization. Here we use PPO RNAi transformants of red clover (Trifolium pratense) to determine the role PPO plays in normal development of plants, and especially in N2-fixing nodules. In red clover, PPO was not essential for either growth or nodule production, or for nodule function in plants grown under optimal, N-free conditions. However, absence of PPO resulted in a more reduced environment in all tissues, as measured by redox potential, and caused subtle developmental changes in nodules. Leaves and, to a lesser extent nodules, lacking PPO tended to accumulate phenolic compounds. A comparison of nodules of two representative contrasting clones by microscopy revealed that nodules lacking PPO were morphologically and anatomically subtly altered, and that phenolics accumulated in different cells and tissues. Developing nodules lacking PPO were longer, and there were more cell layers within the squashed cell layer (SCL), but the walls of these cells were less thickened and the cells were less squashed. Within the N2-fixing zone, bacteroids appeared more granular and were less tightly packed together, and were similar to developmentally compromised bacteroids elicited by catalase mutant rhizobia reported elsewhere. PMID:25566275

  2. Solitary pulmonary nodule

    MedlinePlus

    ... doctor must decide whether the nodule in your lung is most likely benign (not cancer) or of concern. A nodule more likely benign if: The nodule is small, has a smooth border, and has a solid and even appearance on an x-ray or CT scan You are young and do ...

  3. Dammarane saponins from Zizyphus lotus.

    PubMed

    Renault, J H; Ghedira, K; Thepenier, P; Lavaud, C; Zeches-Hanrot, M; Le Men-Olivier, L

    1997-04-01

    Four dammarane-type saponins were isolated by means of centrifugal partition chromatography from the root bark of Zizyphus lotus. Their structures were elucidated using a combination of 1D and 2D 1H and 13C NMR spectra and mass spectroscopy. One of these glycosides is the known jujuboside A. The others are three new dammarane saponins, identified as 3-O-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl (1-->3)-[alpha-L-rhamnopyranosyl(1-->2)]-alpha-L-arabinopyranosyl jujubogenin = jujuboside C, 3-O-alpha-L-rhamnopyranosyl (1-->2)-[beta-D-glucopyranosyl(1-->3)]-beta-D-galactopyranosyl lotogenin = lotoside I, and 3-O-alpha-L-rhamnopyranosyl(1-->2)-[beta-D-glucopyranosyl (1-->3)]-beta-D-glucopyranosyl lotogenin = lotoside II. Lotogenin is a new dammarane derivative identified as (15R, 16R, 20R, 22R)-16 beta, 22-epoxydammar-24-ene-3 beta, 15 alpha, 16 alpha, 20 beta-tetraol. PMID:9115699

  4. Genetic diversity of resident soil rhizobia isolated from nodules of distinct hairy vetch genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hairy vetch (Vicia villosa Roth) is widely grown as a legume cover crop throughout the U.S.A., with biological nitrogen fixation (BNF) through symbiosis with Rhizobium leguminosarum biovar viciae (Rlv) being one of the most sought after benefits of its cultivation. This study determined if HV culti...

  5. Molecular Characterization of LjABCG1, an ATP-Binding Cassette Protein in Lotus japonicus.

    PubMed

    Sugiyama, Akifumi; Fukuda, Shoju; Takanashi, Kojiro; Yoshioka, Miki; Yoshioka, Hirofumi; Narusaka, Yoshihiro; Narusaka, Mari; Kojima, Mikiko; Sakakibara, Hitoshi; Shitan, Nobukazu; Sato, Shusei; Tabata, Satoshi; Kawaguchi, Masayoshi; Yazaki, Kazufumi

    2015-01-01

    LjABCG1, a full-size ABCG subfamily of ATP-binding cassette proteins of a model legume, Lotus japonicus, was reported as a gene highly expressed during the early stages of nodulation, but have not been characterized in detail. In this study we showed that the induction of LjABCG1 expression was remarkable by methyl jasmonate treatment, and reporter gene experiments indicated that LjABCG1 was strongly expressed in the nodule parenchyma and cell layers adjacent to the root vascular tissue toward the nodule. LjABCG1 was suggested to be localized at the plasma membrane based on the fractionation of microsomal membranes as well as separation via aqueous two-phase partitioning. The physiological functions of LjABCG1 in symbiosis and pathogenesis were analyzed in homologous and heterologous systems. LjABCG1 knock-down L. japonicus plants did not show clear phenotypic differences in nodule formation, and not in defense against Pseudomonas syringae, either. In contrast, when LjABCG1 was expressed in the Arabidopsis pdr8-1 mutant, the penetration frequency of Phytophthora infestans, a potato late blight pathogen, was significantly reduced in LjABCG1/pdr8-1 than in pdr8-1 plants. This finding indicated that LjABCG1, at least partially, complemented the phenotype of pdr8 in Arabidopsis, suggesting the multiple roles of this protein in plant-microbe interactions. PMID:26418593

  6. Molecular Characterization of LjABCG1, an ATP-Binding Cassette Protein in Lotus japonicus

    PubMed Central

    Sugiyama, Akifumi; Fukuda, Shoju; Takanashi, Kojiro; Yoshioka, Miki; Yoshioka, Hirofumi; Narusaka, Yoshihiro; Narusaka, Mari; Kojima, Mikiko; Sakakibara, Hitoshi; Shitan, Nobukazu; Sato, Shusei; Tabata, Satoshi; Kawaguchi, Masayoshi; Yazaki, Kazufumi

    2015-01-01

    LjABCG1, a full-size ABCG subfamily of ATP-binding cassette proteins of a model legume, Lotus japonicus, was reported as a gene highly expressed during the early stages of nodulation, but have not been characterized in detail. In this study we showed that the induction of LjABCG1 expression was remarkable by methyl jasmonate treatment, and reporter gene experiments indicated that LjABCG1 was strongly expressed in the nodule parenchyma and cell layers adjacent to the root vascular tissue toward the nodule. LjABCG1 was suggested to be localized at the plasma membrane based on the fractionation of microsomal membranes as well as separation via aqueous two-phase partitioning. The physiological functions of LjABCG1 in symbiosis and pathogenesis were analyzed in homologous and heterologous systems. LjABCG1 knock-down L. japonicus plants did not show clear phenotypic differences in nodule formation, and not in defense against Pseudomonas syringae, either. In contrast, when LjABCG1 was expressed in the Arabidopsis pdr8-1 mutant, the penetration frequency of Phytophthora infestans, a potato late blight pathogen, was significantly reduced in LjABCG1/pdr8-1 than in pdr8-1 plants. This finding indicated that LjABCG1, at least partially, complemented the phenotype of pdr8 in Arabidopsis, suggesting the multiple roles of this protein in plant-microbe interactions. PMID:26418593

  7. Inoculation of Woody Legumes with Selected Arbuscular Mycorrhizal Fungi and Rhizobia To Recover Desertified Mediterranean Ecosystems

    PubMed Central

    Herrera, M. A.; Salamanca, C. P.; Barea, J. M.

    1993-01-01

    Revegetation strategies, either for reclamation or for rehabilitation, are being used to recover desertified ecosystems. Woody legumes are recognized as species that are useful for revegetation of water-deficient, low-nutrient environments because of their ability to form symbiotic associations with rhizobial bacteria and mycorrhizal fungi, which improve nutrient acquisition and help plants to become established and cope with stress situations. A range of woody legumes used in revegetation programs, particularly in Mediterranean regions, were assayed. These legumes included both exotic and native species and were used in a test of a desertified semiarid ecosystem in southeast Spain. Screening for the appropriate plant species-microsymbiont combinations was performed previously, and a simple procedure to produce plantlets with optimized mycorrhizal and nodulated status was developed. The results of a 4-year trial showed that (i) only the native shrub legumes were able to become established under the local environmental conditions (hence, a reclamation strategy is recommended) and (ii) biotechnological manipulation of the seedlings to be used for revegetation (by inoculation with selected rhizobia and mycorrhizal fungi) improved outplanting performance, plant survival, and biomass development. PMID:16348838

  8. OxyR-regulated catalase activity is critical for oxidative stress resistance, nodulation and nitrogen fixation in Azorhizobium caulinodans.

    PubMed

    Zhao, Yue; Nickels, Logan M; Wang, Hui; Ling, Jun; Zhong, Zengtao; Zhu, Jun

    2016-07-01

    The legume-rhizobial interaction results in the formation of symbiotic nodules in which rhizobia fix nitrogen. During the process of symbiosis, reactive oxygen species (ROS) are generated. Thus, the response of rhizobia to ROS is important for successful nodulation and nitrogen fixation. In this study, we investigated how Azorhizobium caulinodans, a rhizobium that forms both root and stem nodules on its host plant, regulates ROS resistance. We found that in-frame deletions of a gene encoding the putative catalase-peroxidase katG or a gene encoding a LysR-family regulatory protein, oxyR, exhibited increased sensitivity to H2O2 We then showed that OxyR positively regulated katG expression in an H2O2-independent fashion. Furthermore, we found that deletion of katG or oxyR led to significant reduction in the number of stem nodules and decrease of nitrogen fixation capacities in symbiosis. Our results revealed that KatG and OxyR are not only critical for antioxidant defense in vitro, but also important for nodule formation and nitrogen fixation during interaction with plant hosts. PMID:27190162

  9. Novel players in the AP2-miR172 regulatory network for common bean nodulation

    PubMed Central

    Íñiguez, Luis P; Nova-Franco, Bárbara; Hernández, Georgina

    2015-01-01

    The intricate regulatory network for floral organogenesis in plants that includes AP2/ERF, SPL and AGL transcription factors, miR172 and miR156 along with other components is well documented, though its complexity and size keep increasing. The miR172/AP2 node was recently proposed as essential regulator in the legume-rhizobia nitrogen-fixing symbiosis. Research from our group contributed to demonstrate the control of common bean (Phaseolus vulgaris) nodulation by miR172c/AP2-1, however no other components of such regulatory network have been reported. Here we propose AGLs as new protagonists in the regulation of common bean nodulation and discuss the relevance of future deeper analysis of the complex AP2 regulatory network for nodule organogenesis in legumes. PMID:26211831

  10. Increasing Nitrogen Fixation and Seed Development in Soybean Requires Complex Adjustments of Nodule Nitrogen Metabolism and Partitioning Processes.

    PubMed

    Carter, Amanda M; Tegeder, Mechthild

    2016-08-01

    Legumes are able to access atmospheric di-nitrogen (N2) through a symbiotic relationship with rhizobia that reside within root nodules. In soybean, following N2 fixation by the bacteroids, ammonia is finally reduced in uninfected cells to allantoin and allantoic acid [1]. These ureides present the primary long-distance transport forms of nitrogen (N), and are exported from nodules via the xylem for shoot N supply. Transport of allantoin and allantoic acid out of nodules requires the function of ureide permeases (UPS1) located in cells adjacent to the vasculature [2, 3]. We expressed a common bean UPS1 transporter in cortex and endodermis cells of soybean nodules and found that delivery of N from nodules to shoot, as well as seed set, was significantly increased. In addition, the number of transgenic nodules was increased and symbiotic N2 fixation per nodule was elevated, indicating that transporter function in nodule N export is a limiting step in bacterial N acquisition. Further, the transgenic nodules showed considerable increases in nodule N assimilation, ureide synthesis, and metabolite levels. This suggests complex adjustments of nodule N metabolism and partitioning processes in support of symbiotic N2 fixation. We propose that the transgenic UPS1 plants display metabolic and allocation plasticity to overcome N2 fixation and seed yield limitations. Overall, it is demonstrated that transporter function in N export from nodules is a key step for enhancing atmospheric N2 fixation and nodule function and for improving shoot N nutrition and seed development in legumes. PMID:27451897

  11. Fixating on metals: new insights into the role of metals in nodulation and symbiotic nitrogen fixation

    PubMed Central

    González-Guerrero, Manuel; Matthiadis, Anna; Sáez, Áez;ngela; Long, Terri A.

    2014-01-01

    Symbiotic nitrogen fixation is one of the most promising and immediate alternatives to the overuse of polluting nitrogen fertilizers for improving plant nutrition. At the core of this process are a number of metalloproteins that catalyze and provide energy for the conversion of atmospheric nitrogen to ammonia, eliminate free radicals produced by this process, and create the microaerobic conditions required by these reactions. In legumes, metal cofactors are provided to endosymbiotic rhizobia within root nodule cortical cells. However, low metal bioavailability is prevalent in most soils types, resulting in widespread plant metal deficiency and decreased nitrogen fixation capabilities. As a result, renewed efforts have been undertaken to identify the mechanisms governing metal delivery from soil to the rhizobia, and to determine how metals are used in the nodule and how they are recycled once the nodule is no longer functional. This effort is being aided by improved legume molecular biology tools (genome projects, mutant collections, and transformation methods), in addition to state-of-the-art metal visualization systems. PMID:24592271

  12. Biometamaterials: Black Ultrathin Gold Film Fabricated on Lotus Leaf.

    PubMed

    Ebihara, Yuusuke; Ota, Ryoichi; Noriki, Takahiro; Shimojo, Masayuki; Kajikawa, Kotaro

    2015-01-01

    We report on a black metamaterial of gold fabricated on a lotus leaf that was used as a template. In spite of the extremely thin gold coating (10-nm thick) on the lotus leaf, the surface shows reflectivity below 0.01 over the entire visible spectral range. Finite-difference time-domain (FDTD) calculations suggest that the low reflectivity stems from the secondary structures on the lotus leaf, where randomly oriented nanorods are distributed. PMID:26530514

  13. Biometamaterials: Black Ultrathin Gold Film Fabricated on Lotus Leaf

    PubMed Central

    Ebihara, Yuusuke; Ota, Ryoichi; Noriki, Takahiro; Shimojo, Masayuki; Kajikawa, Kotaro

    2015-01-01

    We report on a black metamaterial of gold fabricated on a lotus leaf that was used as a template. In spite of the extremely thin gold coating (10-nm thick) on the lotus leaf, the surface shows reflectivity below 0.01 over the entire visible spectral range. Finite-difference time-domain (FDTD) calculations suggest that the low reflectivity stems from the secondary structures on the lotus leaf, where randomly oriented nanorods are distributed. PMID:26530514

  14. Rhizobium anhuiense sp. nov., isolated from effective nodules of Vicia faba and Pisum sativum.

    PubMed

    Zhang, Yu Jing; Zheng, Wen Tao; Everall, Isobel; Young, J Peter W; Zhang, Xiao Xia; Tian, Chang Fu; Sui, Xin Hua; Wang, En Tao; Chen, Wen Xin

    2015-09-01

    Four rhizobia-like strains, isolated from root nodules of Pisum sativum and Vicia faba grown in Anhui and Jiangxi Provinces of China, were grouped into the genus Rhizobium but were distinct from all recognized species of the genus Rhizobium by phylogenetic analysis of 16S rRNA and housekeeping genes. The combined sequences of the housekeeping genes atpD, recA and glnII for strain CCBAU 23252(T) showed 86.9 to 95% similarity to those of known species of the genus Rhizobium. All four strains had nodC and nifH genes and could form effective nodules with Pisum sativum and Vicia faba, and ineffective nodules with Phaseolus vulgaris, but did not nodulate Glycine max, Arachis hypogaea, Medicago sativa, Trifolium repens or Lablab purpureus in cross-nodulation tests. Fatty acid composition, DNA-DNA relatedness and a series of phenotypic tests also separated these strains from members of closely related species. Based on all the evidence, we propose a novel species, Rhizobium anhuiense sp. nov., and designate CCBAU 23252(T) ( = CGMCC 1.12621(T) = LMG 27729(T)) as the type strain. This strain was isolated from a root nodule of Vicia faba and has a DNA G+C content of 61.1 mol% (Tm). PMID:26025940

  15. Micromonospora from nitrogen fixing nodules of alfalfa (Medicago sativa L.). A new promising Plant Probiotic Bacteria.

    PubMed Central

    Martínez-Hidalgo, Pilar; Galindo-Villardón, Purificación; Igual, José M.; Martínez-Molina, Eustoquio

    2014-01-01

    Biotic interactions can improve agricultural productivity without costly and environmentally challenging inputs. Micromonospora strains have recently been reported as natural endophytes of legume nodules but their significance for plant development and productivity has not yet been established. The aim of this study was to determine the diversity and function of Micromonospora isolated from Medicago sativa root nodules. Micromonospora-like strains from field alfalfa nodules were characterized by BOX-PCR fingerprinting and 16S rRNA gene sequencing. The ecological role of the interaction of the 15 selected representative Micromonospora strains was tested in M. sativa. Nodulation, plant growth and nutrition parameters were analyzed. Alfalfa nodules naturally contain abundant and highly diverse populations of Micromonospora, both at the intra- and at interspecific level. Selected Micromonospora isolates significantly increase the nodulation of alfalfa by Ensifer meliloti 1021 and also the efficiency of the plant for nitrogen nutrition. Moreover, they promote aerial growth, the shoot-to-root ratio, and raise the level of essential nutrients. Our results indicate that Micromonospora acts as a Rhizobia Helper Bacteria (RHB) agent and has probiotic effects, promoting plant growth and increasing nutrition efficiency. Its ecological role, biotechnological potential and advantages as a plant probiotic bacterium (PPB) are also discussed. PMID:25227415

  16. Penile Epithelioid Angiomatoid Nodule.

    PubMed

    Pirpiris, Athina; Gilbourd, Daniel; Ranasinghe, Anudini; Dill, Tony; Lynnhtun, Kyaw; Rindani, Rahul

    2015-10-01

    Cutaneous epithelioid angiomatoid nodule is a rare clinical entity that is common on the trunk and limbs. This is the first report of penile cutaneous epithelioid angiomatoid nodule. Although it is a benign entity, it must be differentiated from vascular neoplasms, as it can bear similar clinical and pathologic features. PMID:26171823

  17. [Pulmonary nodules and arachnophobia].

    PubMed

    Colinet, B; Dargent, J-L; Fremault, A

    2014-01-01

    Pulmonary nodules are a common reason for consultation and their investigation must always exclude a possible neoplastic cause. This means that, in addition to a thorough history, investigations may be necessary which are sometimes invasive and therefore potentially a cause of iatrogenic harm. The toxic aetiologies for pulmonary nodules are rare. We report a case of a patient with pulmonary nodules occurring predominantly in the right lung, about 1cm in diameter, non-cavitating without calcification, and sometimes surrounded by a peripheral halo. The nodules were a chance finding during preoperative evaluation. After a comprehensive review, a reaction to an inhaled irritant was the preferred hypothesis, specifically overuse of a compound insecticide containing, in addition to the propellant gas and solvent type hydrocarbon - a mixture of piperonyl butoxide, of esbiothrine and permethrin. Removal of this led to the complete disappearance of nodules. Pathological examination identified bronchiolitis obliterans with organising pneumonia accompanied by non-necrotizing granulomas and lipid vacuoles. PMID:24461445

  18. Bacterial-induced calcium oscillations are common to nitrogen-fixing associations of nodulating legumes and nonlegumes.

    PubMed

    Granqvist, Emma; Sun, Jongho; Op den Camp, Rik; Pujic, Petar; Hill, Lionel; Normand, Philippe; Morris, Richard J; Downie, J Allan; Geurts, Rene; Oldroyd, Giles E D

    2015-08-01

    Plants that form root-nodule symbioses are within a monophyletic 'nitrogen-fixing' clade and associated signalling processes are shared with the arbuscular mycorrhizal symbiosis. Central to symbiotic signalling are nuclear-associated oscillations in calcium ions (Ca(2+) ), occurring in the root hairs of several legume species in response to the rhizobial Nod factor signal. In this study we expanded the species analysed for activation of Ca(2+) oscillations, including nonleguminous species within the nitrogen-fixing clade. We showed that Ca(2+) oscillations are a common feature of legumes in their association with rhizobia, while Cercis, a non-nodulating legume, does not show Ca(2+) oscillations in response to Nod factors from Sinorhizobium fredii NGR234. Parasponia andersonii, a nonlegume that can associate with rhizobia, showed Nod factor-induced calcium oscillations to S. fredii NGR234 Nod factors, but its non-nodulating sister species, Trema tomentosa, did not. Also within the nitrogen-fixing clade are actinorhizal species that associate with Frankia bacteria and we showed that Alnus glutinosa induces Ca(2+) oscillations in root hairs in response to exudates from Frankia alni, but not to S. fredii NGR234 Nod factors. We conclude that the ability to mount Ca(2+) oscillations in response to symbiotic bacteria is a common feature of nodulating species within the nitrogen-fixing clade. PMID:26010117

  19. Ureide assay for measuring nitrogen fixation by nodulated soybean calibrated by sup 15 N methods. [Glycine max

    SciTech Connect

    Herridge, D.F. ); Peoples, M.B. )

    1990-06-01

    We report experiments to quantify the relationships between the relative abundance of ureide-N in root-bleeding sap, vacuum-extracted sap, and hot water extracts of stems and petioles of nodulated soybean (Glycine max (L.) Merrill cv Bragg) and the proportion of plant N derived from nitrogen fixation. Additional experiments examined the effects of plant genotype and strain of rhizobia on these relationships. In each of the five experiments reported, plants of cv Bragg (experiment 1), cv Lincoln (experiments 3, 4, 5), or six cultivars/genotypes (experiment 2) were grown in a sand:vermiculite mixture in large pots in a naturally lit, temperature-controlled glasshouse during summer. Pots were inoculated at sowing with effective Bradyrhizobium japonicum CB 1809 (USDA 136) or with one of 21 different strains of rhizobia. The proportions of plant N derived from nitrogen fixation were determined using {sup 15}N dilution. Results show that assessment of nitrogen fixation by soybean using the ureide technique should now be possible with the standard curves presented, irrespective of genotype or strain of rhizobia occupying the nodules.

  20. Texture and wettability of metallic lotus leaves.

    PubMed

    Frankiewicz, C; Attinger, D

    2016-02-21

    Superhydrophobic surfaces with the self-cleaning behavior of lotus leaves are sought for drag reduction and phase change heat transfer applications. These superrepellent surfaces have traditionally been fabricated by random or deterministic texturing of a hydrophobic material. Recently, superrepellent surfaces have also been made from hydrophilic materials, by deterministic texturing using photolithography, without low-surface energy coating. Here, we show that hydrophilic materials can also be made superrepellent to water by chemical texturing, a stochastic rather than deterministic process. These metallic surfaces are the first analog of lotus leaves, in terms of wettability, texture and repellency. A mechanistic model is also proposed to describe the influence of multiple tiers of roughness on wettability and repellency. This demonstrated ability to make hydrophilic materials superrepellent without deterministic structuring or additional coatings opens the way to large scale and robust manufacturing of superrepellent surfaces. PMID:26537609

  1. LBM program at the LOTUS facility

    SciTech Connect

    File, J.; Haldy, P.A.; Jassby, D.L.; Leo, W.R.; Tsang, F.Y.

    1986-01-01

    The Ecole Polytechnique Federale de Lausanne's (EPFL's) LOTUS facility in Lausanne, Switzerland, consists of a point-neutron deuterium-tritium (D-T) source in a shielded room designed specifically for neutronics experiments with fusion blanket modules. In 1985 the Electric Power Research Institute and EPFL initiated an experimental neutron transport program using irradiation of the Lithium Blanket Module (LBM) by the LOTUS neutron source. The principal objectives of this program are: (a) to test the capability of present-day neutron transport codes to predict the neutronic performance, including tritium breeding, of a reactor-representative blanket module in a relatively simple fast-neutron field and (b) to develop and verify the measurement and data processing procedures that will be used eventually with the LBM experiments at the Tokamak Fusion Test Reactor (TFTR) at Princeton Plasma Physics Lab. (PPPL).

  2. Texture and wettability of metallic lotus leaves

    NASA Astrophysics Data System (ADS)

    Frankiewicz, C.; Attinger, D.

    2016-02-01

    Superhydrophobic surfaces with the self-cleaning behavior of lotus leaves are sought for drag reduction and phase change heat transfer applications. These superrepellent surfaces have traditionally been fabricated by random or deterministic texturing of a hydrophobic material. Recently, superrepellent surfaces have also been made from hydrophilic materials, by deterministic texturing using photolithography, without low-surface energy coating. Here, we show that hydrophilic materials can also be made superrepellent to water by chemical texturing, a stochastic rather than deterministic process. These metallic surfaces are the first analog of lotus leaves, in terms of wettability, texture and repellency. A mechanistic model is also proposed to describe the influence of multiple tiers of roughness on wettability and repellency. This demonstrated ability to make hydrophilic materials superrepellent without deterministic structuring or additional coatings opens the way to large scale and robust manufacturing of superrepellent surfaces.Superhydrophobic surfaces with the self-cleaning behavior of lotus leaves are sought for drag reduction and phase change heat transfer applications. These superrepellent surfaces have traditionally been fabricated by random or deterministic texturing of a hydrophobic material. Recently, superrepellent surfaces have also been made from hydrophilic materials, by deterministic texturing using photolithography, without low-surface energy coating. Here, we show that hydrophilic materials can also be made superrepellent to water by chemical texturing, a stochastic rather than deterministic process. These metallic surfaces are the first analog of lotus leaves, in terms of wettability, texture and repellency. A mechanistic model is also proposed to describe the influence of multiple tiers of roughness on wettability and repellency. This demonstrated ability to make hydrophilic materials superrepellent without deterministic structuring or additional

  3. Characterization of Rhizobium grahamii extrachromosomal replicons and their transfer among rhizobia

    PubMed Central

    2014-01-01

    Background Rhizobium grahamii belongs to a new phylogenetic group of rhizobia together with Rhizobium mesoamericanum and other species. R. grahamii has a broad-host-range that includes Leucaena leucocephala and Phaseolus vulgaris, although it is a poor competitor for P. vulgaris nodulation in the presence of Rhizobium etli or Rhizobium phaseoli strains. This work analyzed the genome sequence and transfer properties of R. grahamii plasmids. Results Genome sequence was obtained from R. grahamii CCGE502 type strain isolated from Dalea leporina in Mexico. The CCGE502 genome comprises one chromosome and two extrachromosomal replicons (ERs), pRgrCCGE502a and pRgrCCGE502b. Additionally, a plasmid integrated in the CCGE502 chromosome was found. The genomic comparison of ERs from this group showed that gene content is more variable than average nucleotide identity (ANI). Well conserved nod and nif genes were found in R. grahamii and R. mesoamericanum with some differences. R. phaseoli Ch24-10 genes expressed in bacterial cells in roots were found to be conserved in pRgrCCGE502b. Regarding conjugative transfer we were unable to transfer the R. grahamii CCGE502 symbiotic plasmid and its megaplasmid to other rhizobial hosts but we could transfer the symbiotic plasmid to Agrobacterium tumefaciens with transfer dependent on homoserine lactones. Conclusion Variable degrees of nucleotide identity and gene content conservation were found among the different R. grahamii CCGE502 replicons in comparison to R. mesoamericanum genomes. The extrachromosomal replicons from R. grahamii were more similar to those found in phylogenetically related Rhizobium species. However, limited similarities of R. grahamii CCGE502 symbiotic plasmid and megaplasmid were observed in other more distant Rhizobium species. The set of conserved genes in R. grahamii comprises some of those that are highly expressed in R. phaseoli on plant roots, suggesting that they play an important role in root colonization

  4. Compatibility of rhizobial genotypes within natural populations of Rhizobium leguminosarum biovar viciae for nodulation of host legumes.

    PubMed

    Laguerre, Gisèle; Louvrier, Philippe; Allard, Marie-Reine; Amarger, Noëlle

    2003-04-01

    Populations of Rhizobium leguminosarum biovar viciae were sampled from two bulk soils, rhizosphere, and nodules of host legumes, fava bean (Vicia faba) and pea (Pisum sativum) grown in the same soils. Additional populations nodulating peas, fava beans, and vetches (Vicia sativa) grown in other soils and fava bean-nodulating strains from various geographic sites were also analyzed. The rhizobia were characterized by repetitive extragenomic palindromic-PCR fingerprinting and/or PCR-restriction fragment length polymorphism (RFLP) of 16S-23S ribosomal DNA intergenic spacers as markers of the genomic background and PCR-RFLP of a nodulation gene region, nodD, as a marker of the symbiotic component of the genome. Pairwise comparisons showed differences among the genetic structures of the bulk soil, rhizosphere, and nodule populations and in the degree of host specificity within the Vicieae cross-inoculation group. With fava bean, the symbiotic genotype appeared to be the preponderant determinant of the success in nodule occupancy of rhizobial genotypes independently of the associated genomic background, the plant genotype, and the soil sampled. The interaction between one particular rhizobial symbiotic genotype and fava bean seems to be highly specific for nodulation and linked to the efficiency of nitrogen fixation. By contrast with bulk soil and fava bean-nodulating populations, the analysis of pea-nodulating populations showed preferential associations between genomic backgrounds and symbiotic genotypes. Both components of the rhizobial genome may influence competitiveness for nodulation of pea, and rhizosphere colonization may be a decisive step in competition for nodule occupancy. PMID:12676710

  5. Symbiotic characterization and diversity of rhizobia associated with native and introduced acacias in arid and semi-arid regions in Algeria.

    PubMed

    Boukhatem, Zineb Faiza; Domergue, Odile; Bekki, Abdelkader; Merabet, Chahinez; Sekkour, Sonia; Bouazza, Fatima; Duponnois, Robin; de Lajudie, Philippe; Galiana, Antoine

    2012-06-01

    The diversity of rhizobia associated with introduced and native Acacia species in Algeria was investigated from soil samples collected across seven districts distributed in arid and semi-arid zones. The in vitro tolerances of rhizobial strains to NaCl and high temperature in pure culture varied greatly regardless of their geographical and host plant origins but were not correlated with the corresponding edaphoclimatic characteristics of the sampling sites, as clearly demonstrated by principal component analysis. Based on 16S rRNA gene sequence comparisons, the 48 new strains isolated were ranked into 10 phylogenetic groups representing five bacterial genera, namely, Ensifer, Mesorhizobium, Rhizobium, Bradyrhizobium, and Ochrobactrum. Acacia saligna, an introduced species, appeared as the most promiscuous host because it was efficiently nodulated with the widest diversity of rhizobia taxa including both fast-growing ones, Rhizobium, Ensifer, and Mesorhizobium, and slow-growing Bradyrhizobium. The five other Acacia species studied were associated with fast-growing bacterial taxa exclusively. No difference in efficiency was found between bacterial taxa isolated from a given Acacia species. The tolerances of strains to salinity and temperature remains to be tested in symbiosis with their host plants to select the most adapted Acacia sp.-LNB taxa associations for further revegetation programs. PMID:22283876

  6. Diversity patterns of Rhizobiaceae communities inhabiting soils, root surfaces and nodules reveal a strong selection of rhizobial partners by legumes.

    PubMed

    Miranda-Sánchez, Fabiola; Rivera, Javier; Vinuesa, Pablo

    2016-09-01

    Current knowledge about rhizobial diversity patterns in non-nodule habitats is scarce, limiting our understanding of basic aspects of rhizobial ecology like competitiveness for nodule occupancy and host effects on community structure. We used a combination of cultivation-dependent and independent approaches to analyse alpha and beta diversity patterns of Rhizobiaceae communities from a conserved seasonally dry tropical forest site in central Mexico and two nearby agricultural fields. Lineage-specific recA amplicon libraries were generated from soil DNA and their sequences compared with those from root surface and nodule isolates recovered in trapping experiments from two native Acacia species and two Phaseolus vulgaris cultivars. Rarefaction analyses revealed that Rhizobiaceae diversity in soils is larger than on root surfaces, and smallest in nodules. A 'rare biosphere'-like distribution of species was found in the three habitats. Multivariate statistical analyses demonstrated that the plant genus exerted a stronger influence than the land-usage regime on the diversity of rhizobia associated with hosts. Rhizobium etli was the dominant Rhizobiaceae found in the soil libraries. It dominated nodulation of Acacia spp. and predominately harboured symbiovar mimosae-like nodC genes. A novel Rhizobium lineage (Rsp1) dominated bean nodulation. Specialist and generalist genotypes for host nodulation were detected in both species. PMID:26395550

  7. Silencing of the chalcone synthase gene in Casuarina glauca highlights the important role of flavonoids during nodulation.

    PubMed

    Abdel-Lateif, Khalid; Vaissayre, Virginie; Gherbi, Hassen; Verries, Clotilde; Meudec, Emmanuelle; Perrine-Walker, Francine; Cheynier, Véronique; Svistoonoff, Sergio; Franche, Claudine; Bogusz, Didier; Hocher, Valérie

    2013-09-01

    Nitrogen-fixing root nodulation is confined to four plant orders, including > 14,000 Leguminosae, one nonlegume genus Parasponia and c. 200 actinorhizal species that form symbioses with rhizobia and Frankia bacterial species, respectively. Flavonoids have been identified as plant signals and developmental regulators for nodulation in legumes and have long been hypothesized to play a critical role during actinorhizal nodulation. However, direct evidence of their involvement in actinorhizal symbiosis is lacking. Here, we used RNA interference to silence chalcone synthase, which is involved in the first committed step of the flavonoid biosynthetic pathway, in the actinorhizal tropical tree Casuarina glauca. Transformed flavonoid-deficient hairy roots were generated and used to study flavonoid accumulation and further nodulation. Knockdown of chalcone synthase expression reduced the level of specific flavonoids and resulted in severely impaired nodulation. Nodule formation was rescued by supplementing the plants with naringenin, which is an upstream intermediate in flavonoid biosynthesis. Our results provide, for the first time, direct evidence of an important role for flavonoids during the early stages of actinorhizal nodulation. PMID:23692063

  8. Legume-rhizobia signal exchange: promiscuity and environmental effects

    PubMed Central

    Lira, Mario A.; Nascimento, Luciana R. S.; Fracetto, Giselle G. M.

    2015-01-01

    Although signal exchange between legumes and their rhizobia is among the best-known examples of this biological process, most of the more characterized data comes from just a few legume species and environmental stresses. Although a relative wealth of information is available for some model legumes and some of the major pulses such as soybean, little is known about tropical legumes. This relative disparity in current knowledge is also apparent in the research on the effects of environmental stress on signal exchange; cool-climate stresses, such as low-soil temperature, comprise a relatively large body of research, whereas high-temperature stresses and drought are not nearly as well understood. Both tropical legumes and their environmental stress-induced effects are increasingly important due to global population growth (the demand for protein), climate change (increasing temperatures and more extreme climate behavior), and urbanization (and thus heavy metals). This knowledge gap for both legumes and their environmental stresses is compounded because whereas most temperate legume-rhizobia symbioses are relatively specific and cultivated under relatively stable environments, the converse is true for tropical legumes, which tend to be promiscuous, and grow in highly variable conditions. This review will clarify some of this missing information and highlight fields in which further research would benefit our current knowledge. PMID:26441880

  9. Legume-rhizobia signal exchange: promiscuity and environmental effects.

    PubMed

    Lira, Mario A; Nascimento, Luciana R S; Fracetto, Giselle G M

    2015-01-01

    Although signal exchange between legumes and their rhizobia is among the best-known examples of this biological process, most of the more characterized data comes from just a few legume species and environmental stresses. Although a relative wealth of information is available for some model legumes and some of the major pulses such as soybean, little is known about tropical legumes. This relative disparity in current knowledge is also apparent in the research on the effects of environmental stress on signal exchange; cool-climate stresses, such as low-soil temperature, comprise a relatively large body of research, whereas high-temperature stresses and drought are not nearly as well understood. Both tropical legumes and their environmental stress-induced effects are increasingly important due to global population growth (the demand for protein), climate change (increasing temperatures and more extreme climate behavior), and urbanization (and thus heavy metals). This knowledge gap for both legumes and their environmental stresses is compounded because whereas most temperate legume-rhizobia symbioses are relatively specific and cultivated under relatively stable environments, the converse is true for tropical legumes, which tend to be promiscuous, and grow in highly variable conditions. This review will clarify some of this missing information and highlight fields in which further research would benefit our current knowledge. PMID:26441880

  10. [Therapy of thyroid nodules].

    PubMed

    Schott, Matthias

    2015-04-01

    Thyroid nodules are frequent in Germany. In about every fourth person thyroid nodules can be detected. Most of them are benign. Signs for malignancy are hypoechogenicity, microcalcifications, an unregular margin and increased blood perfusion. There is no strict indication for the treatment of benign nodules. In most cases iodine supplementation is sufficient. A combination therapy with levothyroxine and iodine is more efficient for the treatment of larger nodules. Subclinical hyperthyroidism caused by an adenoma does not necessarily need to be treated, whereas manifest hyperthyroidism needs to treated in most cases with antithyroid drug therapy. Radioiodine therapy is the classical indication for the treatment of unifocal autonomous adenomas. A largely increased thyroid gland with and without uni- / multifocal adenomas are often operated. PMID:25831118

  11. Gatekeeper Tyrosine Phosphorylation of SYMRK Is Essential for Synchronizing the Epidermal and Cortical Responses in Root Nodule Symbiosis.

    PubMed

    Saha, Sudip; Paul, Anindita; Herring, Laura; Dutta, Ayan; Bhattacharya, Avisek; Samaddar, Sandip; Goshe, Michael B; DasGupta, Maitrayee

    2016-05-01

    Symbiosis receptor kinase (SYMRK) is indispensable for activation of root nodule symbiosis (RNS) at both epidermal and cortical levels and is functionally conserved in legumes. Previously, we reported SYMRK to be phosphorylated on "gatekeeper" Tyr both in vitro as well as in planta. Since gatekeeper phosphorylation was not necessary for activity, the significance remained elusive. Herein, we show that substituting gatekeeper with nonphosphorylatable residues like Phe or Ala significantly affected autophosphorylation on selected targets on activation segment/αEF and β3-αC loop of SYMRK. In addition, the same gatekeeper mutants failed to restore proper symbiotic features in a symrk null mutant where rhizobial invasion of the epidermis and nodule organogenesis was unaffected but rhizobia remain restricted to the epidermis in infection threads migrating parallel to the longitudinal axis of the root, resulting in extensive infection patches at the nodule apex. Thus, gatekeeper phosphorylation is critical for synchronizing epidermal/cortical responses in RNS. PMID:26960732

  12. Lotus alianus, a new species from Cabo Verde and nomeenclatural notes on Lotus section Pedrosia (Fabaceae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lotus alianus J.H. Kirkbr., sp. nov., is described and illustrated. It is a rare endemic species from the Republic of Cape Verde, and is found in dry habitats on just two islands, Ilhas de Santo Antao and Sao Vicente. In addition, two species names are synonymized with L. creticus L., and a lectotyp...

  13. Molecular Signals Controlling the Inhibition of Nodulation by Nitrate in Medicago truncatula

    PubMed Central

    van Noorden, Giel E.; Verbeek, Rob; Dinh, Quy Dung; Jin, Jian; Green, Alexandra; Ng, Jason Liang Pin; Mathesius, Ulrike

    2016-01-01

    The presence of nitrogen inhibits legume nodule formation, but the mechanism of this inhibition is poorly understood. We found that 2.5 mM nitrate and above significantly inhibited nodule initiation but not root hair curling in Medicago trunatula. We analyzed protein abundance in M. truncatula roots after treatment with either 0 or 2.5 mM nitrate in the presence or absence of its symbiont Sinorhizobium meliloti after 1, 2 and 5 days following inoculation. Two-dimensional gel electrophoresis combined with mass spectrometry was used to identify 106 differentially accumulated proteins responding to nitrate addition, inoculation or time point. While flavonoid-related proteins were less abundant in the presence of nitrate, addition of Nod gene-inducing flavonoids to the Sinorhizobium culture did not rescue nodulation. Accumulation of auxin in response to rhizobia, which is also controlled by flavonoids, still occurred in the presence of nitrate, but did not localize to a nodule initiation site. Several of the changes included defense- and redox-related proteins, and visualization of reactive oxygen species indicated that their induction in root hairs following Sinorhizobium inoculation was inhibited by nitrate. In summary, the presence of nitrate appears to inhibit nodulation via multiple pathways, including changes to flavonoid metabolism, defense responses and redox changes. PMID:27384556

  14. Molecular Signals Controlling the Inhibition of Nodulation by Nitrate in Medicago truncatula.

    PubMed

    van Noorden, Giel E; Verbeek, Rob; Dinh, Quy Dung; Jin, Jian; Green, Alexandra; Ng, Jason Liang Pin; Mathesius, Ulrike

    2016-01-01

    The presence of nitrogen inhibits legume nodule formation, but the mechanism of this inhibition is poorly understood. We found that 2.5 mM nitrate and above significantly inhibited nodule initiation but not root hair curling in Medicago trunatula. We analyzed protein abundance in M. truncatula roots after treatment with either 0 or 2.5 mM nitrate in the presence or absence of its symbiont Sinorhizobium meliloti after 1, 2 and 5 days following inoculation. Two-dimensional gel electrophoresis combined with mass spectrometry was used to identify 106 differentially accumulated proteins responding to nitrate addition, inoculation or time point. While flavonoid-related proteins were less abundant in the presence of nitrate, addition of Nod gene-inducing flavonoids to the Sinorhizobium culture did not rescue nodulation. Accumulation of auxin in response to rhizobia, which is also controlled by flavonoids, still occurred in the presence of nitrate, but did not localize to a nodule initiation site. Several of the changes included defense- and redox-related proteins, and visualization of reactive oxygen species indicated that their induction in root hairs following Sinorhizobium inoculation was inhibited by nitrate. In summary, the presence of nitrate appears to inhibit nodulation via multiple pathways, including changes to flavonoid metabolism, defense responses and redox changes. PMID:27384556

  15. MtSWEET11, a Nodule-Specific Sucrose Transporter of Medicago truncatula.

    PubMed

    Kryvoruchko, Igor S; Sinharoy, Senjuti; Torres-Jerez, Ivone; Sosso, Davide; Pislariu, Catalina I; Guan, Dian; Murray, Jeremy; Benedito, Vagner A; Frommer, Wolf B; Udvardi, Michael K

    2016-05-01

    Optimization of nitrogen fixation by rhizobia in legumes is a key area of research for sustainable agriculture. Symbiotic nitrogen fixation (SNF) occurs in specialized organs called nodules and depends on a steady supply of carbon to both plant and bacterial cells. Here we report the functional characterization of a nodule-specific Suc transporter, MtSWEET11 from Medicago truncatula MtSWEET11 belongs to a clade of plant SWEET proteins that are capable of transporting Suc and play critical roles in pathogen susceptibility. When expressed in mammalian cells, MtSWEET11 transported sucrose (Suc) but not glucose (Glc). The MtSWEET11 gene was found to be expressed in infected root hair cells, and in the meristem, invasion zone, and vasculature of nodules. Expression of an MtSWEET11-GFP fusion protein in nodules resulted in green fluorescence associated with the plasma membrane of uninfected cells and infection thread and symbiosome membranes of infected cells. Two independent Tnt1-insertion sweet11 mutants were uncompromised in SNF Therefore, although MtSWEET11 appears to be involved in Suc distribution within nodules, it is not crucial for SNF, probably because other Suc transporters can fulfill its role(s). PMID:27021190

  16. MtSWEET11, a Nodule-Specific Sucrose Transporter of Medicago truncatula1[OPEN

    PubMed Central

    Torres-Jerez, Ivone; Sosso, Davide; Guan, Dian; Frommer, Wolf B.

    2016-01-01

    Optimization of nitrogen fixation by rhizobia in legumes is a key area of research for sustainable agriculture. Symbiotic nitrogen fixation (SNF) occurs in specialized organs called nodules and depends on a steady supply of carbon to both plant and bacterial cells. Here we report the functional characterization of a nodule-specific Suc transporter, MtSWEET11 from Medicago truncatula. MtSWEET11 belongs to a clade of plant SWEET proteins that are capable of transporting Suc and play critical roles in pathogen susceptibility. When expressed in mammalian cells, MtSWEET11 transported sucrose (Suc) but not glucose (Glc). The MtSWEET11 gene was found to be expressed in infected root hair cells, and in the meristem, invasion zone, and vasculature of nodules. Expression of an MtSWEET11-GFP fusion protein in nodules resulted in green fluorescence associated with the plasma membrane of uninfected cells and infection thread and symbiosome membranes of infected cells. Two independent Tnt1-insertion sweet11 mutants were uncompromised in SNF. Therefore, although MtSWEET11 appears to be involved in Suc distribution within nodules, it is not crucial for SNF, probably because other Suc transporters can fulfill its role(s). PMID:27021190

  17. Analysis of LBM experiments at LOTUS

    SciTech Connect

    Stepanek, J.; Davidson, J.W.; Dudziak, D.J.; Haldy, P.A.; Pelloni, S.

    1986-01-01

    A Lithium Blanket Module (LBM) has been designed at General Atomic Company (under subcontract to Princeton Plasma Physics Lab. (PPPL), the Electric Power Research Institute (EPRI) contractor) for testing on the Tokamak Fusion Test Reactor (TFTR). The LBM has both realistic fusion blanket materials and configuration and has been designed for detailed experimental analyses of tritium breeding and neutron flux spatial/spectral distributions. It is approx. 80 cm/sup 3/ and the breeding material is Li/sub 2/O. This configuration will be evaluated experimentally at the LOTUS facility and computationally by the LANL/EIR analysis program.

  18. Basis for the competitiveness of rhizobium japonicum in nodulation of soybean. Final progress report

    SciTech Connect

    Bauer, W.D.; Evans, W.R.

    1984-07-30

    These studies were concerned with the determination of the characteristics of the soybean symbiont R. japonicum that are crucial to the inoculum competitiveness of one strain of the bacterium over other strains with respect to nodule formation. Our work has been focused on the initial infection events, such as attachment, which precede the development of a fully functional nodule because it is these primary events which determine the success or failure of a particular rhizobia to initiate infections. Experiments concerned with the attachment of R. japonicum to soybean roots have indicated that both soybean symbiotic and non-symbiotic species of rhizobia attach comparably well to soybean roots. There was no evidence of attachment mediated by soybean lectin, as previously claimed, but evidence was obtained for attachment mediated by pili on the Rhizobium cells. It was also found that the efficiency of infection varied substantially with culture age for certain strains while with other strains the efficiency of infection remained approximately constant during growth. We have utilized these observations to investigate the relationship between the efficiency of infection and competitiveness. An unexpected outcome of these studies was the finding that R. japonicum, and other slow-growing Rhizobium species, maintain both viability and symbiotic infectivity over prolonged periods of storage at ambient temperatures when suspended in water. The simplicity and cost-effectiveness of this storage procedure may provide an alternative method to the current practices employed in inoculum preparation. 2 figures, 3 tables.

  19. Relevance of Fucose-Rich Extracellular Polysaccharides Produced by Rhizobium sullae Strains Nodulating Hedysarum coronarium L. Legumes

    PubMed Central

    Carpéné, Marie-Anne; Couderc, François; Benguedouar, Ammar

    2013-01-01

    Specific and complex interactions between soil bacteria, known as rhizobia, and their leguminous host plants result in the development of root nodules. This process implies a complex dialogue between the partners. Rhizobia synthesize different classes of polysaccharides: exopolysaccharides (EPS), Kdo-rich capsular polysaccharides, lipopolysaccharides, and cyclic β-(1,2)-glucans. These polymers are actors of a successful symbiosis with legumes. We focus here on studying the EPS produced by Rhizobium sullae bacteria that nodulate Hedysarum coronarium L., largely distributed in Algeria. We describe the influence of the carbon source on the production and on the composition of EPS produced by R. sullae A6 and RHF strains. High-molecular-weight EPS preserve the bacteria from desiccation. The structural characterization of the EPS produced by R. sullae strains has been performed through sugar analysis by gas chromatography-mass spectrometry. The low-molecular-weight EPS of one strain (RHF) has been totally elucidated using nuclear magnetic resonance and quantitative time-of-flight tandem mass spectrometry analyses. An unusual fucose-rich EPS has been characterized. The presence of this deoxy sugar seems to be related to nodulation capacity. PMID:23183977

  20. Rhizobium pongamiae sp. nov. from Root Nodules of Pongamia pinnata

    PubMed Central

    Kesari, Vigya; Ramesh, Aadi Moolam; Rangan, Latha

    2013-01-01

    Pongamia pinnata has an added advantage of N2-fixing ability and tolerance to stress conditions as compared with other biodiesel crops. It harbours “rhizobia” as an endophytic bacterial community on its root nodules. A gram-negative, nonmotile, fast-growing, rod-shaped, bacterial strain VKLR-01T was isolated from root nodules of Pongamia that grew optimal at 28°C, pH 7.0 in presence of 2% NaCl. Isolate VKLR-01 exhibits higher tolerance to the prevailing adverse conditions, for example, salt stress, elevated temperatures and alkalinity. Strain VKLR-01T has the major cellular fatty acid as C18:1  ω7c (65.92%). Strain VKLR-01T was found to be a nitrogen fixer using the acetylene reduction assay and PCR detection of a nifH gene. On the basis of phenotypic, phylogenetic distinctiveness and molecular data (16S rRNA, recA, and atpD gene sequences, G + C content, DNA-DNA hybridization etc.), strain VKLR-01T = (MTCC 10513T = MSCL 1015T) is considered to represent a novel species of the genus Rhizobium for which the name Rhizobium pongamiae sp. nov. is proposed. Rhizobium pongamiae may possess specific traits that can be transferred to other rhizobia through biotechnological tools and can be directly used as inoculants for reclamation of wasteland; hence, they are very important from both economic and environmental prospects. PMID:24078904

  1. The Genetics of Symbiotic Nitrogen Fixation: Comparative Genomics of 14 Rhizobia Strains by Resolution of Protein Clusters

    PubMed Central

    Black, Michael; Moolhuijzen, Paula; Chapman, Brett; Barrero, Roberto; Howieson, John; Hungria, Mariangela; Bellgard, Matthew

    2012-01-01

    The symbiotic relationship between legumes and nitrogen fixing bacteria is critical for agriculture, as it may have profound impacts on lowering costs for farmers, on land sustainability, on soil quality, and on mitigation of greenhouse gas emissions. However, despite the importance of the symbioses to the global nitrogen cycling balance, very few rhizobial genomes have been sequenced so far, although there are some ongoing efforts in sequencing elite strains. In this study, the genomes of fourteen selected strains of the order Rhizobiales, all previously fully sequenced and annotated, were compared to assess differences between the strains and to investigate the feasibility of defining a core ‘symbiome’—the essential genes required by all rhizobia for nodulation and nitrogen fixation. Comparison of these whole genomes has revealed valuable information, such as several events of lateral gene transfer, particularly in the symbiotic plasmids and genomic islands that have contributed to a better understanding of the evolution of contrasting symbioses. Unique genes were also identified, as well as omissions of symbiotic genes that were expected to be found. Protein comparisons have also allowed the identification of a variety of similarities and differences in several groups of genes, including those involved in nodulation, nitrogen fixation, production of exopolysaccharides, Type I to Type VI secretion systems, among others, and identifying some key genes that could be related to host specificity and/or a better saprophytic ability. However, while several significant differences in the type and number of proteins were observed, the evidence presented suggests no simple core symbiome exists. A more abstract systems biology concept of nitrogen fixing symbiosis may be required. The results have also highlighted that comparative genomics represents a valuable tool for capturing specificities and generalities of each genome. PMID:24704847

  2. Responses of lucerne (Medicago sativa L.) and rhizobia to copper-based fungicide application in two contrasting soils

    NASA Astrophysics Data System (ADS)

    Schneider, Martin; Dober, Melanie; Jöchlinger, Lisa; Keiblinger, Katharina; Soja, Gerhard; Mentler, Axel; Zechmeister-Boltenstern, Sophie; Bruckner, Alexander; Golestani Fard, Alireza; Wenzel, Walter; Zehetner, Franz

    2016-04-01

    For more than 120 years, salts of copper (Cu) have been used in viticulture to prevent damages by fungal diseases. Due to restrictions in the use of synthetic fungicides and mineral fertilizers, organic viticulture depends on Cu as well as on biological nitrogen fixation. Here, we conducted an eco-toxicological pot experiment with an acidic, sandy soil and a calcareous, loamy soil and incrementally increasing fungicide application rates from 0 to 5000 mg Cu kg-1 soil. Lucerne (Medicago sativa L. cultivar. Plato) was grown in the pots for 3 months under greenhouse conditions. Acetylene reduction assays performed with harvested nodules showed no response to elevated soil Cu concentrations indicating that the nitrogen fixing capacity of rhizobia was not compromised by Cu in our experiment. Nevertheless, the nodule biomass was very sensitive to Cu and strongly decreased due to reduced amounts of fine roots and less energy supply by the plant. Legumes are known to be Cu-sensitive, and our contribution also showed a decrease in harvest by 50 % (EC50) at 21 mg kg-1 plant Cu tissue concentration in the acidic soil and at 30 mg kg-1 in the calcareous soil. This corresponded to diffusional fluxes measured by diffusive gradients in thin films (DGT) of 202 and 368 fmol cm-2 s-1, respectively. DGT measurements showed that in the acidic soil, Cu was 2 to 10 times more available for plants, depending on the concentration applied, than in the calcareous soil. A modeling approach for estimating the effective concentration (EC) by including the DGT-estimated plant Cu content and the pH produced more accurate values (NRMSE of 21.9 to 20.1 %) than EC directly estimated from DGT.

  3. Antiulcerogenic activity of Zizyphus lotus (L.) extracts.

    PubMed

    Wahida, Borgi; Abderrahman, Bouraoui; Nabil, Chouchane

    2007-06-13

    Oral administration of aqueous extracts of Zizyphus lotus root barks (50-200 mg/kg) leaves (50-200 mg/kg) and fruits (200-400 mg/kg) produced a significant (p<0.01) and dose dependent inhibition to the acute ulcer induced by HCl/ethanol solution. The methanolic (MeOH), ethyl acetate (EtOAc) and chloroformic (CHCl(3)) leaves extracts when administered orally at the dose of 200 mg/kg, exhibited a significant (p<0.01) inhibition of gastric lesions by 45%, 76% and 33%, respectively. Indeed, methanolic and ethyl acetate root barks extracts significantly reduced the gastric lesions by 47% and 41%, respectively. While the chloroformic root barks extract had no significant activity (19%). The effect of all extracts was compared with cimetidine (100 mg/kg, 62%) and omeprazole (30 mg/kg, 93%). Volume, pH and acidity of gastric juice were studied in pylorus-ligated rats. Root barks (200 mg/kg, p<0.01), leaves (200 mg/kg, p<0.01) and fruits (400 mg/kg, p<0.05) aqueous extracts showed significant reduction of gastric juice secretion in pylorus ligated rats, whereas the other extracts did not show any significance. Thus, Zizyphus lotus extracts act essentially as cytoprotective agents, which support the antiulcer effect of this plant in the traditional medicine. PMID:17408894

  4. Functional Conservation of the Capacity for ent-Kaurene Biosynthesis and an Associated Operon in Certain Rhizobia

    PubMed Central

    Hershey, David M.; Lu, Xuan; Zi, Jiachen

    2014-01-01

    Bacterial interactions with plants are accompanied by complex signal exchange processes. Previously, the nitrogen-fixing symbiotic (rhizo)bacterium Bradyrhizobium japonicum was found to carry adjacent genes encoding two sequentially acting diterpene cyclases that together transform geranylgeranyl diphosphate to ent-kaurene, the olefin precursor to the gibberellin plant hormones. Species from the three other major genera of rhizobia were found to have homologous terpene synthase genes. Cloning and functional characterization of a representative set of these enzymes confirmed the capacity of each genus to produce ent-kaurene. Moreover, comparison of their genomic context revealed that these diterpene synthases are found in a conserved operon which includes an adjacent isoprenyl diphosphate synthase, shown here to produce the geranylgeranyl diphosphate precursor, providing a critical link to central metabolism. In addition, the rest of the operon consists of enzymatic genes that presumably lead to a more elaborated diterpenoid, although the production of gibberellins was not observed. Nevertheless, it has previously been shown that the operon is selectively expressed during nodulation, and the scattered distribution of the operon via independent horizontal gene transfer within the symbiotic plasmid or genomic island shown here suggests that such diterpenoid production may modulate the interaction of these particular symbionts with their host plants. PMID:24142247

  5. Identification and Dynamic Regulation of microRNAs Involved in Salt Stress Responses in Functional Soybean Nodules by High-Throughput Sequencing

    PubMed Central

    Dong, Zhanghui; Shi, Lei; Wang, Yanwei; Chen, Liang; Cai, Zhaoming; Wang, Youning; Jin, Jingbo; Li, Xia

    2013-01-01

    Both symbiosis between legumes and rhizobia and nitrogen fixation in functional nodules are dramatically affected by salt stress. Better understanding of the molecular mechanisms that regulate the salt tolerance of functional nodules is essential for genetic improvement of nitrogen fixation efficiency. microRNAs (miRNAs) have been implicated in stress responses in many plants and in symbiotic nitrogen fixation (SNF) in soybean. However, the dynamic regulation of miRNAs in functioning nodules during salt stress response remains unknown. We performed deep sequencing of miRNAs to understand the miRNA expression profile in normal or salt stressed-soybean mature nodules. We identified 110 known miRNAs belonging to 61 miRNA families and 128 novel miRNAs belonging to 64 miRNA families. Among them, 104 miRNAs were dramatically differentially expressed (>2-fold or detected only in one library) during salt stress. qRT-PCR analysis of eight miRNAs confirmed that these miRNAs were dynamically regulated in response to salt stress in functional soybean nodules. These data significantly increase the number of miRNAs known to be expressed in soybean nodules, and revealed for the first time a dynamic regulation of miRNAs during salt stress in functional nodules. The findings suggest great potential for miRNAs in functional soybean nodules during salt stress. PMID:23358256

  6. A metabolic gene cluster in Lotus japonicus discloses novel enzyme functions and products in triterpene biosynthesis.

    PubMed

    Krokida, Afrodite; Delis, Costas; Geisler, Katrin; Garagounis, Constantine; Tsikou, Daniela; Peña-Rodríguez, Luis M; Katsarou, Dimitra; Field, Ben; Osbourn, Anne E; Papadopoulou, Kalliope K

    2013-11-01

    Genes for triterpene biosynthetic pathways exist as metabolic gene clusters in oat and Arabidopsis thaliana plants. We characterized the presence of an analogous gene cluster in the model legume Lotus japonicus. In the genomic regions flanking the oxidosqualene cyclase AMY2 gene, genes for two different classes of cytochrome P450 and a gene predicted to encode a reductase were identified. Functional characterization of the cluster genes was pursued by heterologous expression in Nicotiana benthamiana. The gene expression pattern was studied under different developmental and environmental conditions. The physiological role of the gene cluster in nodulation and plant development was studied in knockdown experiments. A novel triterpene structure, dihydrolupeol, was produced by AMY2. A new plant cytochrome P450, CYP71D353, which catalyses the formation of 20-hydroxybetulinic acid in a sequential three-step oxidation of 20-hydroxylupeol was characterized. The genes within the cluster are highly co-expressed during root and nodule development, in hormone-treated plants and under various environmental stresses. A transcriptional gene silencing mechanism that appears to be involved in the regulation of the cluster genes was also revealed. A tightly co-regulated cluster of functionally related genes is involved in legume triterpene biosynthesis, with a possible role in plant development. PMID:23909862

  7. Accumulation of extracellular proteins bearing unique proline-rich motifs in intercellular spaces of the legume nodule parenchyma.

    PubMed

    Sherrier, D J; Taylor, G S; Silverstein, K A T; Gonzales, M B; VandenBosch, K A

    2005-04-01

    Nodulins encoding repetitive proline-rich cell wall proteins (PRPs) are induced during early interactions with rhizobia, suggesting a massive restructuring of the plant extracellular matrix during infection and nodulation. However, the proteins corresponding to these gene products have not been isolated or characterized, nor have cell wall localizations been confirmed. Posttranslational modifications, conformation, and interactions with other wall polymers are difficult to predict on the basis of only the deduced amino acid sequence of PRPs. PsENOD2 is expressed in nodule parenchyma tissue during nodule organogenesis and encodes a protein with distinctive PRP motifs that are rich in glutamate and basic amino acids. A database search for the ENOD2 signature motifs indicates that similar proteins may have a limited phylogenetic distribution, as they are presently only known from legumes. To determine the ultrastructural location of the proteins, antibodies were raised against unique motifs from the predicted ENOD2 sequence. The antibodies recognized nodule-specific proteins in pea (Pisum sativum), with a major band detected at 110 kDa, representing a subset of PRPs from nodules. The protein was detected specifically in organelles of the secretory pathway and intercellular spaces in the nodule parenchyma, but it was not abundant in primary walls. Similar proteins with an analogous distribution were detected in soybean (Glycine max). The use of polyclonal antibodies raised against signature motifs of extracellular matrix proteins thus appears to be an effective strategy to identify and isolate specific structural proteins for functional analysis. PMID:15868212

  8. Root exudates drive interspecific facilitation by enhancing nodulation and N2 fixation.

    PubMed

    Li, Bai; Li, Yu-Ying; Wu, Hua-Mao; Zhang, Fang-Fang; Li, Chun-Jie; Li, Xue-Xian; Lambers, Hans; Li, Long

    2016-06-01

    Plant diversity in experimental systems often enhances ecosystem productivity, but the mechanisms causing this overyielding are only partly understood. Intercropping faba beans (Vicia faba L.) and maize (Zea mays L.) result in overyielding and also, enhanced nodulation by faba beans. By using permeable and impermeable root barriers in a 2-y field experiment, we show that root-root interactions between faba bean and maize significantly increase both nodulation and symbiotic N2 fixation in intercropped faba bean. Furthermore, root exudates from maize promote faba bean nodulation, whereas root exudates from wheat and barley do not. Thus, a decline of soil nitrate concentrations caused by intercropped cereals is not the sole mechanism for maize promoting faba bean nodulation. Intercropped maize also caused a twofold increase in exudation of flavonoids (signaling compounds for rhizobia) in the systems. Roots of faba bean treated with maize root exudates exhibited an immediate 11-fold increase in the expression of chalcone-flavanone isomerase (involved in flavonoid synthesis) gene together with a significantly increased expression of genes mediating nodulation and auxin response. After 35 d, faba beans treated with maize root exudate continued to show up-regulation of key nodulation genes, such as early nodulin 93 (ENOD93), and promoted nitrogen fixation. Our results reveal a mechanism for how intercropped maize promotes nitrogen fixation of faba bean, where maize root exudates promote flavonoid synthesis in faba bean, increase nodulation, and stimulate nitrogen fixation after enhanced gene expression. These results indicate facilitative root-root interactions and provide a mechanism for a positive relationship between species diversity and ecosystem productivity. PMID:27217575

  9. Root exudates drive interspecific facilitation by enhancing nodulation and N2 fixation

    PubMed Central

    Li, Bai; Li, Yu-Ying; Wu, Hua-Mao; Zhang, Fang-Fang; Li, Chun-Jie; Li, Xue-Xian; Lambers, Hans; Li, Long

    2016-01-01

    Plant diversity in experimental systems often enhances ecosystem productivity, but the mechanisms causing this overyielding are only partly understood. Intercropping faba beans (Vicia faba L.) and maize (Zea mays L.) result in overyielding and also, enhanced nodulation by faba beans. By using permeable and impermeable root barriers in a 2-y field experiment, we show that root–root interactions between faba bean and maize significantly increase both nodulation and symbiotic N2 fixation in intercropped faba bean. Furthermore, root exudates from maize promote faba bean nodulation, whereas root exudates from wheat and barley do not. Thus, a decline of soil nitrate concentrations caused by intercropped cereals is not the sole mechanism for maize promoting faba bean nodulation. Intercropped maize also caused a twofold increase in exudation of flavonoids (signaling compounds for rhizobia) in the systems. Roots of faba bean treated with maize root exudates exhibited an immediate 11-fold increase in the expression of chalcone–flavanone isomerase (involved in flavonoid synthesis) gene together with a significantly increased expression of genes mediating nodulation and auxin response. After 35 d, faba beans treated with maize root exudate continued to show up-regulation of key nodulation genes, such as early nodulin 93 (ENOD93), and promoted nitrogen fixation. Our results reveal a mechanism for how intercropped maize promotes nitrogen fixation of faba bean, where maize root exudates promote flavonoid synthesis in faba bean, increase nodulation, and stimulate nitrogen fixation after enhanced gene expression. These results indicate facilitative root–root interactions and provide a mechanism for a positive relationship between species diversity and ecosystem productivity. PMID:27217575

  10. The Independent Acquisition of Plant Root Nitrogen-Fixing Symbiosis in Fabids Recruited the Same Genetic Pathway for Nodule Organogenesis

    PubMed Central

    Svistoonoff, Sergio; Benabdoun, Faiza Meriem; Nambiar-Veetil, Mathish; Imanishi, Leandro; Vaissayre, Virginie; Cesari, Stella; Diagne, Nathalie; Hocher, Valérie; de Billy, Françoise; Bonneau, Jocelyne; Wall, Luis; Ykhlef, Nadia; Rosenberg, Charles; Bogusz, Didier; Franche, Claudine; Gherbi, Hassen

    2013-01-01

    Only species belonging to the Fabid clade, limited to four classes and ten families of Angiosperms, are able to form nitrogen-fixing root nodule symbioses (RNS) with soil bacteria. This concerns plants of the legume family (Fabaceae) and Parasponia (Cannabaceae) associated with the Gram-negative proteobacteria collectively called rhizobia and actinorhizal plants associated with the Gram-positive actinomycetes of the genus Frankia. Calcium and calmodulin-dependent protein kinase (CCaMK) is a key component of the common signaling pathway leading to both rhizobial and arbuscular mycorrhizal symbioses (AM) and plays a central role in cross-signaling between root nodule organogenesis and infection processes. Here, we show that CCaMK is also needed for successful actinorhiza formation and interaction with AM fungi in the actinorhizal tree Casuarina glauca and is also able to restore both nodulation and AM symbioses in a Medicago truncatula ccamk mutant. Besides, we expressed auto-active CgCCaMK lacking the auto-inhibitory/CaM domain in two actinorhizal species: C. glauca (Casuarinaceae), which develops an intracellular infection pathway, and Discaria trinervis (Rhamnaceae) which is characterized by an ancestral intercellular infection mechanism. In both species, we found induction of nodulation independent of Frankia similar to response to the activation of CCaMK in the rhizobia-legume symbiosis and conclude that the regulation of actinorhiza organogenesis is conserved regardless of the infection mode. It has been suggested that rhizobial and actinorhizal symbioses originated from a common ancestor with several independent evolutionary origins. Our findings are consistent with the recruitment of a similar genetic pathway governing rhizobial and Frankia nodule organogenesis. PMID:23741336

  11. The independent acquisition of plant root nitrogen-fixing symbiosis in Fabids recruited the same genetic pathway for nodule organogenesis.

    PubMed

    Svistoonoff, Sergio; Benabdoun, Faiza Meriem; Nambiar-Veetil, Mathish; Imanishi, Leandro; Vaissayre, Virginie; Cesari, Stella; Diagne, Nathalie; Hocher, Valérie; de Billy, Françoise; Bonneau, Jocelyne; Wall, Luis; Ykhlef, Nadia; Rosenberg, Charles; Bogusz, Didier; Franche, Claudine; Gherbi, Hassen

    2013-01-01

    Only species belonging to the Fabid clade, limited to four classes and ten families of Angiosperms, are able to form nitrogen-fixing root nodule symbioses (RNS) with soil bacteria. This concerns plants of the legume family (Fabaceae) and Parasponia (Cannabaceae) associated with the Gram-negative proteobacteria collectively called rhizobia and actinorhizal plants associated with the Gram-positive actinomycetes of the genus Frankia. Calcium and calmodulin-dependent protein kinase (CCaMK) is a key component of the common signaling pathway leading to both rhizobial and arbuscular mycorrhizal symbioses (AM) and plays a central role in cross-signaling between root nodule organogenesis and infection processes. Here, we show that CCaMK is also needed for successful actinorhiza formation and interaction with AM fungi in the actinorhizal tree Casuarina glauca and is also able to restore both nodulation and AM symbioses in a Medicago truncatula ccamk mutant. Besides, we expressed auto-active CgCCaMK lacking the auto-inhibitory/CaM domain in two actinorhizal species: C. glauca (Casuarinaceae), which develops an intracellular infection pathway, and Discaria trinervis (Rhamnaceae) which is characterized by an ancestral intercellular infection mechanism. In both species, we found induction of nodulation independent of Frankia similar to response to the activation of CCaMK in the rhizobia-legume symbiosis and conclude that the regulation of actinorhiza organogenesis is conserved regardless of the infection mode. It has been suggested that rhizobial and actinorhizal symbioses originated from a common ancestor with several independent evolutionary origins. Our findings are consistent with the recruitment of a similar genetic pathway governing rhizobial and Frankia nodule organogenesis. PMID:23741336

  12. The neutronic analysis for the LBM/LOTUS experiment

    SciTech Connect

    Kolibal, J.G.; Ku, L.P.; Liew, S.L.

    1986-11-01

    A comparison of the two dimensional discrete ordinates and three dimensional Monte Carlo calculations for the Lithium Blanket Module at the LOTUS facility is made. These models are for comparison with the experimental data.

  13. Solitary liver nodules.

    PubMed

    Fisher, A W; Curry, B; Jacques, J

    1975-05-17

    There has been confusion in the literature over the nomenclature of solitary liver nodules. Several such lesions have recently been reported in patients taking oral contraceptives. Similarities exist between these cases that suggest they may be examples of focal nodular hyperplasia. Here three further cases are presented. The criteria for making the diagnosis and its importance are discussed. PMID:165001

  14. Solitary pulmonary nodule

    MedlinePlus

    ... chest x-ray Pulmonary nodule, solitary - CT scan Respiratory system References Gotway MB, Panse PM, Gruden JF, Elicker BM. Thoracic radiology. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine . 6th ed. Philadelphia, PA: Elsevier Saunders; 2016: ...

  15. Function of glutathione peroxidases in legume root nodules.

    PubMed

    Matamoros, Manuel A; Saiz, Ana; Peñuelas, Maria; Bustos-Sanmamed, Pilar; Mulet, Jose M; Barja, Maria V; Rouhier, Nicolas; Moore, Marten; James, Euan K; Dietz, Karl-Josef; Becana, Manuel

    2015-05-01

    Glutathione peroxidases (Gpxs) are antioxidant enzymes not studied so far in legume nodules, despite the fact that reactive oxygen species are produced at different steps of the symbiosis. The function of two Gpxs that are highly expressed in nodules of the model legume Lotus japonicus was examined. Gene expression analysis, enzymatic and nitrosylation assays, yeast cell complementation, in situ mRNA hybridization, immunoelectron microscopy, and LjGpx-green fluorescent protein (GFP) fusions were used to characterize the enzymes and to localize each transcript and isoform in nodules. The LjGpx1 and LjGpx3 genes encode thioredoxin-dependent phospholipid hydroperoxidases and are differentially regulated in response to nitric oxide (NO) and hormones. LjGpx1 and LjGpx3 are nitrosylated in vitro or in plants treated with S-nitrosoglutathione (GSNO). Consistent with the modification of the peroxidatic cysteine of LjGpx3, in vitro assays demonstrated that this modification results in enzyme inhibition. The enzymes are highly expressed in the infected zone, but the LjGpx3 mRNA is also detected in the cortex and vascular bundles. LjGpx1 is localized to the plastids and nuclei, and LjGpx3 to the cytosol and endoplasmic reticulum. Based on yeast complementation experiments, both enzymes protect against oxidative stress, salt stress, and membrane damage. It is concluded that both LjGpxs perform major antioxidative functions in nodules, preventing lipid peroxidation and other oxidative processes at different subcellular sites of vascular and infected cells. The enzymes are probably involved in hormone and NO signalling, and may be regulated through nitrosylation of the peroxidatic cysteine essential for catalytic function. PMID:25740929

  16. Function of glutathione peroxidases in legume root nodules

    PubMed Central

    Matamoros, Manuel A.; Saiz, Ana; Peñuelas, Maria; Bustos-Sanmamed, Pilar; Mulet, Jose M.; Barja, Maria V.; Rouhier, Nicolas; Moore, Marten; James, Euan K.; Dietz, Karl-Josef; Becana, Manuel

    2015-01-01

    Glutathione peroxidases (Gpxs) are antioxidant enzymes not studied so far in legume nodules, despite the fact that reactive oxygen species are produced at different steps of the symbiosis. The function of two Gpxs that are highly expressed in nodules of the model legume Lotus japonicus was examined. Gene expression analysis, enzymatic and nitrosylation assays, yeast cell complementation, in situ mRNA hybridization, immunoelectron microscopy, and LjGpx-green fluorescent protein (GFP) fusions were used to characterize the enzymes and to localize each transcript and isoform in nodules. The LjGpx1 and LjGpx3 genes encode thioredoxin-dependent phospholipid hydroperoxidases and are differentially regulated in response to nitric oxide (NO) and hormones. LjGpx1 and LjGpx3 are nitrosylated in vitro or in plants treated with S-nitrosoglutathione (GSNO). Consistent with the modification of the peroxidatic cysteine of LjGpx3, in vitro assays demonstrated that this modification results in enzyme inhibition. The enzymes are highly expressed in the infected zone, but the LjGpx3 mRNA is also detected in the cortex and vascular bundles. LjGpx1 is localized to the plastids and nuclei, and LjGpx3 to the cytosol and endoplasmic reticulum. Based on yeast complementation experiments, both enzymes protect against oxidative stress, salt stress, and membrane damage. It is concluded that both LjGpxs perform major antioxidative functions in nodules, preventing lipid peroxidation and other oxidative processes at different subcellular sites of vascular and infected cells. The enzymes are probably involved in hormone and NO signalling, and may be regulated through nitrosylation of the peroxidatic cysteine essential for catalytic function. PMID:25740929

  17. Functional Domain Analysis of the Remorin Protein LjSYMREM1 in Lotus japonicus

    PubMed Central

    Madsen, Esben B.; Ye, Juanying; Popp, Claudia; Antolín-Llovera, Meritxell; Grossmann, Christina; Jensen, Ole N.; Schüßler, Arthur; Parniske, Martin; Ott, Thomas

    2012-01-01

    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 belonging to the same phylogenetic group are similar to each other throughout the plant kingdom, the N-terminal domains of legume-specific group 2 Remorins show exceptional high degrees of sequence divergence suggesting evolutionary specialization of this protein within this clade. We therefore identified and characterized the MtSYMREM1 ortholog from Lotus japonicus (LjSYMREM1), a model legume that forms determinate root nodules. Here, we resolved its spatio-temporal regulation and showed that over-expression of LjSYMREM1 increases nodulation on transgenic roots. Using a structure-function approach we show that protein interactions including Remorin oligomerization are mainly mediated and stabilized by the Remorin C-terminal region with its coiled-coil domain while the RLK kinase domains transiently interact in vivo and phosphorylate a residue in the N-terminal region of the LjSYMREM1 protein in vitro. These data provide novel insights into the mechanism of this putative molecular scaffold protein and underline its importance during rhizobial infection. PMID:22292047

  18. Phylogenetic diversity of rhizobial species and symbiovars nodulating Phaseolus vulgaris in Iran.

    PubMed

    Rouhrazi, Kiomars; Khodakaramian, Gholam; Velázquez, Encarna

    2016-03-01

    The phylogenetic diversity of 29 rhizobial strains nodulating Phaseolus vulgaris in Iran was analysed on the basis of their core and symbiotic genes. These strains displayed five 16S rRNA-RFLP patterns and belong to eight ERIC-PCR clusters. The phylogenetic analyses of 16S rRNA, recA and atpD core genes allowed the identification of several strains as Rhizobium sophoriradicis, R. leguminosarum, R. tropici and Pararhizobium giardinii, whereas other strains represented a new phylogenetic lineage related to R. vallis. These strains and those identified as R. sophoriradicis and R. leguminosarum belong to the symbiovar phaseoli carrying the γ nodC allele distributed in P. vulgaris endosymbionts in America, Europe, Africa and Asia. The strain identified as R. tropici belongs to the symbiovar tropici carried by strains of R. tropici, R. leucaenae, R. lusitanum and R. freirei nodulating P. vulgaris in America, Africa and Asia. The strain identified as P. giardinii belongs to the symbiovar giardinii together with the type strain of this species nodulating P. vulgaris in France. It is remarkable that the recently described species R. sophoriradicis is worldwide distributed in P. vulgaris nodules carrying the γ nodC allele of symbiovar phaseoli harboured by rhizobia isolated in the American distribution centers of this legume. PMID:26832644

  19. Current Advances in the Metabolomics Study on Lotus Seeds

    PubMed Central

    Zhu, Mingzhi; Liu, Ting; Guo, Mingquan

    2016-01-01

    Lotus (Nelumbo nucifera), which is distributed widely throughout Asia, Australia and North America, is an aquatic perennial that has been cultivated for over 2,000 years. It is very stimulating that almost all parts of lotus have been consumed as vegetable as well as food, especially the seeds. Except for the nutritive values of lotus, there has been increasing interest in its potential as functional food due to its rich secondary metabolites, such as flavonoids and alkaloids. Not only have these metabolites greatly contributed to the biological process of lotus seeds, but also have been reported to possess multiple health-promoting effects, including antioxidant, anti-amnesic, anti-inflammatory, and anti-tumor activities. Thus, comprehensive metabolomic profiling of these metabolites is of key importance to help understand their biological activities, and other chemical biology features. In this context, this review will provide an update on the current technological platforms, and workflow associated with metabolomic studies on lotus seeds, as well as insights into the application of metabolomics for the improvement of food safety and quality, assisting breeding, and promotion of the study of metabolism and pharmacokinetics of lotus seeds; meanwhile it will also help explore new perspectives and outline future challenges in this fast-growing research subject. PMID:27379154

  20. Current Advances in the Metabolomics Study on Lotus Seeds.

    PubMed

    Zhu, Mingzhi; Liu, Ting; Guo, Mingquan

    2016-01-01

    Lotus (Nelumbo nucifera), which is distributed widely throughout Asia, Australia and North America, is an aquatic perennial that has been cultivated for over 2,000 years. It is very stimulating that almost all parts of lotus have been consumed as vegetable as well as food, especially the seeds. Except for the nutritive values of lotus, there has been increasing interest in its potential as functional food due to its rich secondary metabolites, such as flavonoids and alkaloids. Not only have these metabolites greatly contributed to the biological process of lotus seeds, but also have been reported to possess multiple health-promoting effects, including antioxidant, anti-amnesic, anti-inflammatory, and anti-tumor activities. Thus, comprehensive metabolomic profiling of these metabolites is of key importance to help understand their biological activities, and other chemical biology features. In this context, this review will provide an update on the current technological platforms, and workflow associated with metabolomic studies on lotus seeds, as well as insights into the application of metabolomics for the improvement of food safety and quality, assisting breeding, and promotion of the study of metabolism and pharmacokinetics of lotus seeds; meanwhile it will also help explore new perspectives and outline future challenges in this fast-growing research subject. PMID:27379154

  1. The Study of Runoff Loads from Lotus Paddy Fields

    NASA Astrophysics Data System (ADS)

    Kuroda, Hisao; Kato, Tasuku; Nakasone, Hideo

    To solve the problem of diffuse pollution brought about of eutrophication in lakes, an investigation was conducted in lotus paddy fields, at which little research had been conducted. The study area consisted of low-land lotus paddy fields around the Lake Kasumigaura watershed in Ibaraki Prefecture. The area is well known as the largest production center of lotus roots in Japan. The results of the study show that the mass balance loads of total nitrogen(T-N), total phosphorus(T-P), chemical oxygen demand(COD), and suspended solids from the lotus paddy fields were -3.22 , 1.87, 75.36 and 552 kg·km-2·d-1, respectively. Comparing these values to the unit reported in "The Fifth Plan for Water Quality Conservation in the Lakes and Ponds related to Lake Kasumigaura", it was found that T-N was purified, T-P was 2.1 times higher and COD was 4.8 times higher. It was found that the major cause of the effluent loads was the outflow of suspended matters during puddling and lotus planting. The dissolved matter was influenced by the increase of discharge. The suspended matter discharge from the lotus paddy fields temporarily accumulated at the end of the drainage canals and flowed out when there was a rainfall.

  2. LOTUS template for calculating well logs

    SciTech Connect

    Mitchell, R.J. ); Taylor, S.J. )

    1993-09-01

    Calculating well logs is a time-consuming process. This template uses input parameters consisting of well name, location county, state, formation name, starting depth, repeat interval, resistivity of shale, and irreducible bulk volume water, which provides heading information for print outs. Required information from basic well logs are porosity, conductivity (optional), formation resistivity, resistivity of the formation water for the zone being calculated, resistivity of the mud filtrate, the porosity cutoff for pay in the zone being calculated, and the saltwater saturation cutoff for the pay zone. These parameters are used to calculate apparent water resistivity, saltwater saturation, bulk volume water, ratio of apparent water resistivity to input water resistivity, irreducible saltwater saturation, resistivity volume of shale, permeability, and a derived porosity value. A print out of the results is available through the lotus print function. Using this template allows maximum control of the input parameters and reduces hand calculation time.

  3. Analysis of the lbm experiments at lotus

    SciTech Connect

    Stepenek, J.; Higgs, C.E.; Pelloni, S.; Davidson, J.W.; Dudziak, D.J.

    1986-11-01

    The irradiation of the LBM at the LOTUS facility is analysed using a three-dimensional model with the Monte Carlo code MCNP and a two-dimensional r-z model with the deterministic transport code TRISM. A sensitivity and uncertainty analysis based on the 2-D model was performed using the sensitivity code SENSIT-2D. The JEF-1/EFF and ENDF/B-V libraries were used for transport calculations. The COVFILS-2 covariance and uncertainty library based on ENDF/B-V was used for sensitivity and uncertainty analyses. A good agreement between JEF-l/EFF and ENDF/B-V libraries was achieved. The uncertainty in the calculated tritium breeding ratio by the indirect term of the overall cross-section uncertainties varies in the dependence on the position in the LBM from 1.4% (front) to 35.8% (back).

  4. Defense Responses in Two Ecotypes of Lotus japonicus against Non-Pathogenic Pseudomonas syringae

    PubMed Central

    Bordenave, Cesar D.; Escaray, Francisco J.; Menendez, Ana B.; Serna, Eva; Carrasco, Pedro; Ruiz, Oscar A.; Gárriz, Andrés

    2013-01-01

    Lotus japonicus is a model legume broadly used to study many important processes as nitrogen fixing nodule formation and adaptation to salt stress. However, no studies on the defense responses occurring in this species against invading microorganisms have been carried out at the present. Understanding how this model plant protects itself against pathogens will certainly help to develop more tolerant cultivars in economically important Lotus species as well as in other legumes. In order to uncover the most important defense mechanisms activated upon bacterial attack, we explored in this work the main responses occurring in the phenotypically contrasting ecotypes MG-20 and Gifu B-129 of L. japonicus after inoculation with Pseudomonas syringae DC3000 pv. tomato. Our analysis demonstrated that this bacterial strain is unable to cause disease in these accessions, even though the defense mechanisms triggered in these ecotypes might differ. Thus, disease tolerance in MG-20 was characterized by bacterial multiplication, chlorosis and desiccation at the infiltrated tissues. In turn, Gifu B-129 plants did not show any symptom at all and were completely successful in restricting bacterial growth. We performed a microarray based analysis of these responses and determined the regulation of several genes that could play important roles in plant defense. Interestingly, we were also able to identify a set of defense genes with a relative high expression in Gifu B-129 plants under non-stress conditions, what could explain its higher tolerance. The participation of these genes in plant defense is discussed. Our results position the L. japonicus-P. syringae interaction as a interesting model to study defense mechanisms in legume species. PMID:24349460

  5. A CDPK isoform participates in the regulation of nodule number in Medicago truncatula.

    PubMed

    Gargantini, Pablo R; Gonzalez-Rizzo, Silvina; Chinchilla, Delphine; Raices, Marcela; Giammaria, Verónica; Ulloa, Rita M; Frugier, Florian; Crespi, Martin D

    2006-12-01

    Medicago spp. are able to develop root nodules via symbiotic interaction with Sinorhizobium meliloti. Calcium-dependent protein kinases (CDPKs) are involved in various signalling pathways in plants, and we found that expression of MtCPK3, a CDPK isoform present in roots of the model legume Medicago truncatula, is regulated during the nodulation process. Early inductions were detected 15 min and 3-4 days post-inoculation (dpi). The very early induction of CPK3 messengers was also present in inoculated M. truncatula dmi mutants and in wild-type roots subjected to salt stress, indicating that this rapid response is probably stress-related. In contrast, the later response was concomitant with cortical cell division and the formation of nodule primordia, and was not observed in wild-type roots inoculated with nod (-) strains. This late induction correlated with a change in the subcellular distribution of CDPK activities. Accordingly, an anti-MtCPK3 antibody detected two bands in soluble root extracts and one in the particulate fraction. CPK3::GFP fusions are targeted to the plasma membrane in epidermal onion cells, a localization that depends on myristoylation and palmitoylation sites of the protein, suggesting a dual subcellular localization. MtCPK3 mRNA and protein were also up-regulated by cytokinin treatment, a hormone linked to the regulation of cortical cell division and other nodulation-related responses. An RNAi-CDPK construction was used to silence CPK3 in Agrobacterium rhizogenes-transformed roots. Although no major phenotype was detected in these roots, when infected with rhizobia, the total number of nodules was, on average, twofold higher than in controls. This correlates with the lack of MtCPK3 induction in the inoculated super-nodulator sunn mutant. Our results suggest that CPK3 participates in the regulation of the symbiotic interaction. PMID:17132148

  6. Phosphorus homeostasis in legume nodules as an adaptive strategy to phosphorus deficiency.

    PubMed

    Sulieman, Saad; Tran, Lam-Son Phan

    2015-10-01

    Legumes have a significant role in effective management of fertilizers and improving soil health in sustainable agriculture. Because of the high phosphorus (P) requirements of N2-fixing nodule, P deficiency represents an important constraint for legume crop production, especially in tropical marginal countries. P deficiency is an important constraint for legume crop production, especially in poor soils present in many tropical degraded areas. Unlike nitrogen, mineral P sources are nonrenewable, and high-grade rock phosphates are expected to be depleted in the near future. Accordingly, developing legume cultivars with effective N2 fixation under P-limited conditions could have a profound significance for improving agricultural sustainability. Legumes have evolved strategies at both morphological and physiological levels to adapt to P deficiency. Molecular mechanisms underlying the adaptive strategies to P deficiency have been elucidated in legumes. These include maintenance of the P-homeostasis in nodules as a main adaptive strategy for rhizobia-legume symbiosis under P deficiency. The stabilization of P levels in the symbiotic tissues can be achieved through several mechanisms, including elevated P allocation to nodules, formation of a strong P sink in nodules, direct P acquisition via nodule surface and P remobilization from organic-P containing substances. The detailed biochemical, physiological and molecular understanding will be essential to the advancement of genetic and molecular approaches for enhancement of legume adaptation to P deficiency. In this review, we evaluate recent progress made to gain further and deeper insights into the physiological, biochemical and molecular reprogramming that legumes use to maintain P-homeostasis in nodules during P scarcity. PMID:26398789

  7. Rhizobia and their bio-partners as novel drivers for functional remediation in contaminated soils

    PubMed Central

    Teng, Ying; Wang, Xiaomi; Li, Lina; Li, Zhengao; Luo, Yongming

    2015-01-01

    Environmental pollutants have received considerable attention due to their serious effects on human health. There are physical, chemical, and biological means to remediate pollution; among them, bioremediation has become increasingly popular. The nitrogen-fixing rhizobia are widely distributed in the soil and root ecosystems and can increase legume growth and production by supplying nitrogen, resulting in the reduced need for fertilizer applications. Rhizobia also possess the biochemical and ecological capacity to degrade organic pollutants and are resistant to heavy metals, making them useful for rehabilitating contaminated soils. Moreover, rhizobia stimulate the survival and action of other biodegrading bacteria, thereby lowering the concentration of pollutants. The synergistic action of multiple rhizobial strains enhances both plant growth and the availability of pollutants ranging from heavy metals to persistent organic pollutants. Because phytoremediation has some restrictions, the beneficial interaction between plants and rhizobia provides a promising option for remediation. This review describes recent advances in the exploitation of rhizobia for the rehabilitation of contaminated soil and the biochemical and molecular mechanisms involved, thereby promoting further development of this novel bioremediation strategy into a widely accepted technique. PMID:25699064

  8. Diversity pattern of nitrogen fixing microbes in nodules of Trifolium arvense (L.) at different initial stages of ecosystem development

    NASA Astrophysics Data System (ADS)

    Schulz, S.; Engel, M.; Fischer, D.; Buegger, F.; Elmer, M.; Welzl, G.; Schloter, M.

    2013-02-01

    Legumes can be considered as pioneer plants during ecosystem development, as they form a symbiosis with different nitrogen fixing rhizobia species, which enable the plants to grow on soils with low available nitrogen content. In this study we compared the abundance and diversity of nitrogen fixing microbes based on the functional marker gene nifH, which codes for a subunit of the Fe-protein of the dinitrogenase reductase, in nodules of different size classes of Trifolium arvense (L.). Additionally, carbon and nitrogen contents of the bulk soil and plant material were measured. Plants were harvested from different sites, reflecting 2 (2a) and 5 (5a) yr of ecosystem development, of an opencast lignite mining area in the south of Cottbus, Lower Lusatia (Germany) where the artificial catchment "Chicken Creek" was constructed to study the development of terrestrial ecosystems. Plants from the 5a site revealed higher amounts of carbon and nitrogen, although nifH gene abundances in the nodules and carbon and nitrogen contents between the two soils did not differ significantly. Analysis of the nifH clone libraries showed a significant effect of the nodule size on the community composition of nitrogen fixing microbes. Medium sized nodules (2-5 mm) contained a uniform community composed of Rhizobium leguminosarum bv. trifolii, whereas the small nodules (<2 mm) consisted of a diverse community including clones with non-Rhizobium nifH gene sequences. Regarding the impact of the soil age on the community composition a clear distinction between the small and the medium nodules can be made. While clone libraries from the medium nodules were pretty similar at both soil ages, soil age had a significant effect on the community compositions of the small nodules, where the proportion of R. leguminosarum bv. trifolii increased with soil age.

  9. Diversity pattern of nitrogen fixing microbes in nodules of Trifolium arvense (L.) at different initial stages of ecosystem development

    NASA Astrophysics Data System (ADS)

    Schulz, S.; Engel, M.; Fischer, D.; Buegger, F.; Elmer, M.; Welzl, G.; Schloter, M.

    2012-09-01

    Legumes can be considered as pioneer plants during ecosystem development, as they form a symbiosis with different nitrogen fixing rhizobia species, which enable the plants to grow on soils with low available nitrogen content. In this study we compared the abundance and diversity of nitrogen fixing microbes based on the functional marker gene nifH, which codes for a subunit of the Fe-protein of the dinitrogenase reductase, in nodules of different size classes of Trifolium arvense (L.). Additionally, carbon and nitrogen contents of the bulk soil and plant material were measured. Plants were harvested from different sites, reflecting 2 (2a) and 5 (5a) yr of ecosystem development, of an opencast lignite mining area in the south of Cottbus, Lower Lusatia (Germany) where the artificial catchment "Chicken Creek" was constructed to study the development of terrestrial ecosystems. Plants from the 5a site revealed higher amounts of carbon and nitrogen, although nifH gene abundances in the nodules and carbon and nitrogen contents between the two soils did not differ significantly. Analysis of the nifH clone libraries showed a significant effect of the nodule size on the community composition of nitrogen fixing microbes. Medium sized nodules (2-5 mm) contained a uniform community composed of Rhizobium leguminosarum bv. trifolii, whereas the small nodules (< 2 mm) consisted of a diverse community including clones with non-Rhizobium nifH gene sequences. Regarding the impact of the soil age on the community composition a clear distinction between the small and the medium nodules can be made. While clone libraries from the medium nodules were pretty similar at both soil ages, soil age had a significant effect on the community compositions of the small nodules, where the proportion of R. leguminosarum bv. trifolii increased with soil age.

  10. Terminal bacteroid differentiation in the legume-rhizobium symbiosis: nodule-specific cysteine-rich peptides and beyond.

    PubMed

    Alunni, Benoît; Gourion, Benjamin

    2016-07-01

    Contents 411 I. 411 II. 412 III. 412 IV. 413 V. 414 VI. 414 VII. 415 VIII. 415 416 References 416 SUMMARY: Terminal bacteroid differentiation (TBD) is a remarkable case of bacterial cell differentiation that occurs after rhizobia are released intracellularly within plant cells of symbiotic legume organs called nodules. The hallmarks of TBD are cell enlargement, genome amplification and membrane permeabilization. This plant-driven process is governed by a large family of bacteroid-targeted nodule-specific cysteine-rich (NCR) peptides that were until recently thought to be restricted to a specific lineage of the legume family, including the model plant Medicago truncatula. Recently, new plant and bacterial factors involved in TBD have been identified, challenging our view of this phenomenon at mechanistic and evolutionary levels. Here, we review the recent literature and discuss emerging questions about the mechanisms and the role(s) of TBD. PMID:27241115

  11. CERBERUS, a novel U-box protein containing WD-40 repeats, is required for formation of the infection thread and nodule development in the legume-Rhizobium symbiosis.

    PubMed

    Yano, Koji; Shibata, Satoshi; Chen, Wen-Li; Sato, Shusei; Kaneko, Takakazu; Jurkiewicz, Anna; Sandal, Niels; Banba, Mari; Imaizumi-Anraku, Haruko; Kojima, Tomoko; Ohtomo, Ryo; Szczyglowski, Krzysztof; Stougaard, Jens; Tabata, Satoshi; Hayashi, Makoto; Kouchi, Hiroshi; Umehara, Yosuke

    2009-10-01

    Endosymbiotic infection of legume plants by Rhizobium bacteria is initiated through infection threads (ITs) which are initiated within and penetrate from root hairs and deliver the endosymbionts into nodule cells. Despite recent progress in understanding the mutual recognition and early symbiotic signaling cascades in host legumes, the molecular mechanisms underlying bacterial infection processes and successive nodule organogenesis are still poorly understood. We isolated a novel symbiotic mutant of Lotus japonicus, cerberus, which shows defects in IT formation and nodule organogenesis. Map-based cloning of the causal gene allowed us to identify the CERBERUS gene, which encodes a novel protein containing a U-box domain and WD-40 repeats. CERBERUS expression was detected in the roots and nodules, and was enhanced after inoculation of Mesorhizobium loti. Strong expression was detected in developing nodule primordia and the infected zone of mature nodules. In cerberus mutants, Rhizobium colonized curled root hair tips, but hardly penetrated into root hair cells. The occasional ITs that were formed inside the root hair cells were mostly arrested within the epidermal cell layer. Nodule organogenesis was aborted prematurely, resulting in the formation of a large number of small bumps which contained no endosymbiotic bacteria. These phenotypic and genetic analyses, together with comparisons with other legume mutants with defects in IT formation, indicate that CERBERUS plays a critical role in the very early steps of IT formation as well as in growth and differentiation of nodules. PMID:19508425

  12. Molecular responses of Lotus japonicus to parasitism by the compatible species Orobanche aegyptiaca and the incompatible species Striga hermonthica

    PubMed Central

    Hiraoka, Yukihiro; Ueda, Hiroaki; Sugimoto, Yukihiro

    2009-01-01

    Lotus japonicus genes responsive to parasitism by the compatible species Orobanche aegyptiaca and the incompatible species Striga hermonthica were isolated by using the suppression subtractive hybridization (SSH) strategy. O. aegyptiaca and S. hermonthica parasitism specifically induced the expression of genes involved in jasmonic acid (JA) biosynthesis and phytoalexin biosynthesis, respectively. Nodulation-related genes were almost exclusively found among the Orobanche-induced genes. Temporal gene expression analyses revealed that 19 out of the 48 Orobanche-induced genes and 5 out of the 48 Striga-induced genes were up-regulated at 1 dai. Four genes, including putative trypsin protease inhibitor genes, exhibited systemic up-regulation in the host plant parasitized by O. aegyptiaca. On the other hand, S. hermonthica attachment did not induce systemic gene expression. PMID:19088337

  13. The genome of the long-living Sacred lotus (Nelumbo nucifera, Gaertn.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sacred lotus, a basal eudicot of agricultural, medicinal, cultural, and religious importance, is particularly noted for its 1,300-year seed longevity, and for its outstanding water repellency, the "lotus effect”. The genome sequence of the Sacred lotus variety 'China Antique' lacks the paleo-triplic...

  14. A Phylogenetically Conserved Group of Nuclear Factor-Y Transcription Factors Interact to Control Nodulation in Legumes1[OPEN

    PubMed Central

    Laloum, Tom; Lepage, Agnès; Ariel, Federico; Frances, Lisa; Gamas, Pascal; de Carvalho-Niebel, Fernanda

    2015-01-01

    The endosymbiotic association between legumes and soil bacteria called rhizobia leads to the formation of a new root-derived organ called the nodule in which differentiated bacteria convert atmospheric nitrogen into a form that can be assimilated by the host plant. Successful root infection by rhizobia and nodule organogenesis require the activation of symbiotic genes that are controlled by a set of transcription factors (TFs). We recently identified Medicago truncatula nuclear factor-YA1 (MtNF-YA1) and MtNF-YA2 as two M. truncatula TFs playing a central role during key steps of the Sinorhizobium meliloti-M. truncatula symbiotic interaction. NF-YA TFs interact with NF-YB and NF-YC subunits to regulate target genes containing the CCAAT box consensus sequence. In this study, using a yeast two-hybrid screen approach, we identified the NF-YB and NF-YC subunits able to interact with MtNF-YA1 and MtNF-YA2. In yeast (Saccharomyces cerevisiae) and in planta, we further demonstrated by both coimmunoprecipitation and bimolecular fluorescence complementation that these NF-YA, -B, and -C subunits interact and form a stable NF-Y heterotrimeric complex. Reverse genetic and chromatin immunoprecipitation-PCR approaches revealed the importance of these newly identified NF-YB and NF-YC subunits for rhizobial symbiosis and binding to the promoter of MtERN1 (for Ethylene Responsive factor required for Nodulation), a direct target gene of MtNF-YA1 and MtNF-YA2. Finally, we verified that a similar trimer is formed in planta by the common bean (Phaseolus vulgaris) NF-Y subunits, revealing the existence of evolutionary conserved NF-Y protein complexes to control nodulation in leguminous plants. This sheds light on the process whereby an ancient heterotrimeric TF mainly controlling cell division in animals has acquired specialized functions in plants. PMID:26432878

  15. Four new dammarane saponins from Zizyphus lotus.

    PubMed

    Maciuk, Alexandre; Lavaud, Catherine; Thépenier, Philippe; Jacquier, Marie-José; Ghédira, Kamel; Zèches-Hanrot, Monique

    2004-10-01

    Five dammarane-type saponins were isolated by means of centrifugal partition chromatography from the leaves of Zizyphus lotus. Their structures were elucidated using a combination of 1D and 2D 1H and 13C NMR spectra and mass spectroscopy. One of these glycosides is the known jujuboside B (5). Three are new jujubogenin glycosides, identified as 3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranosyljujubogenin-20-O-(2,3,4-O-triacetyl)-alpha-L-rhamnopyranoside (1), 3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranosyljujubogenin-20-O-alpha-L-rhamnopyranoside (2), and 3-O-alpha-L-rhamnopyranosyl-(1-->2)-[(4-sulfo)-beta-D-glucopyranosyl-(1-->3)]-alpha-L-arabinopyranosyljujubogenin (3). The last is a new sulfated derivative of jujubasaponine IV, identified as 3-O-alpha-L-rhamnopyranosyl-(1-->2)-[(4-sulfo)-beta-D-glucopyranosyl-(1-->3)]-beta-D-galactopyranosyl-(20R,22R)-16beta,22:16alpha,30-diepoxydammar-24-ene-3beta,20-diol (4). PMID:15497932

  16. LOTUS: a low-cost, ultraviolet spectrograph

    NASA Astrophysics Data System (ADS)

    Steele, I. A.; Marchant, J. M.; Jermak, H. E.; Barnsley, R. M.; Bates, S. D.; Clay, N. R.; Fitzsimmons, A.; Jehin, E.; Jones, G.; Mottram, C. J.; Smith, R. J.; Snodgrass, C.; de Val-Borro, M.

    2016-08-01

    We describe the design, construction and commissioning of LOTUS; a simple, low-cost long-slit spectrograph for the Liverpool Telescope. The design is optimized for near-UV and visible wavelengths and uses all transmitting optics. It exploits the instrument focal plane field curvature to partially correct axial chromatic aberration. A stepped slit provides narrow (2.5x95 arcsec) and wide (5x25 arcsec) options that are optimized for spectral resolution and flux calibration respectively. On sky testing shows a wavelength range of 3200-6300 Angstroms with a peak system throughput (including detector quantum efficiency) of 15 per cent and wavelength dependant spectral resolution of R=225-430. By repeated observations of the symbiotic emission line star AG Peg we demonstrate the wavelength stability of the system is less than 2 Angstroms rms and is limited by the positioning of the object in the slit. The spectrograph is now in routine operation monitoring the activity of comet 67P/Churyumov-Gerasimenko during its current post-perihelion apparition.

  17. Genome Structure of the Legume, Lotus japonicus

    PubMed Central

    Sato, Shusei; Nakamura, Yasukazu; Kaneko, Takakazu; Asamizu, Erika; Kato, Tomohiko; Nakao, Mitsuteru; Sasamoto, Shigemi; Watanabe, Akiko; Ono, Akiko; Kawashima, Kumiko; Fujishiro, Tsunakazu; Katoh, Midori; Kohara, Mitsuyo; Kishida, Yoshie; Minami, Chiharu; Nakayama, Shinobu; Nakazaki, Naomi; Shimizu, Yoshimi; Shinpo, Sayaka; Takahashi, Chika; Wada, Tsuyuko; Yamada, Manabu; Ohmido, Nobuko; Hayashi, Makoto; Fukui, Kiichi; Baba, Tomoya; Nakamichi, Tomoko; Mori, Hirotada; Tabata, Satoshi

    2008-01-01

    The legume Lotus japonicus has been widely used as a model system to investigate the genetic background of legume-specific phenomena such as symbiotic nitrogen fixation. Here, we report structural features of the L. japonicus genome. The 315.1-Mb sequences determined in this and previous studies correspond to 67% of the genome (472 Mb), and are likely to cover 91.3% of the gene space. Linkage mapping anchored 130-Mb sequences onto the six linkage groups. A total of 10 951 complete and 19 848 partial structures of protein-encoding genes were assigned to the genome. Comparative analysis of these genes revealed the expansion of several functional domains and gene families that are characteristic of L. japonicus. Synteny analysis detected traces of whole-genome duplication and the presence of synteny blocks with other plant genomes to various degrees. This study provides the first opportunity to look into the complex and unique genetic system of legumes. PMID:18511435

  18. LOTUS: A low cost, ultraviolet spectrograph

    NASA Astrophysics Data System (ADS)

    Steele, I. A.; Marchant, J. M.; Jermak, H. E.; Barnsley, R. M.; Bates, S. D.; Clay, N. R.; Fitzsimmons, A.; Jehin, E.; Jones, G.; Mottram, C. J.; Smith, R. J.; Snodgrass, C.; de Val-Borro, M.

    2016-05-01

    We describe the design, construction and commissioning of LOTUS; a simple, low-cost long-slit spectrograph for the Liverpool Telescope. The design is optimized for near-UV and visible wavelengths and uses all transmitting optics. It exploits the instrument focal plane field curvature to partially correct axial chromatic aberration. A stepped slit provides narrow (2.5 × 95 arcsec) and wide (5 × 25 arcsec) options that are optimized for spectral resolution and flux calibration respectively. On sky testing shows a wavelength range of 3200-6300 Å with a peak system throughput (including detector quantum efficiency) of 15 per cent and wavelength dependant spectral resolution of R = 225 - 430. By repeated observations of the symbiotic emission line star AG Peg we demonstrate the wavelength stability of the system is <2 Å rms and is limited by the positioning of the object in the slit. The spectrograph is now in routine operation monitoring the activity of comet 67P/Churyumov-Gerasimenko during its current post-perihelion apparition.

  19. Genetic Diversity and Evolution of Bradyrhizobium Populations Nodulating Erythrophleum fordii, an Evergreen Tree Indigenous to the Southern Subtropical Region of China

    PubMed Central

    Yao, Yao; Wang, Rui; Lu, Jun Kun; Wang, En Tao; Chen, Wen Xin

    2014-01-01

    The nodulation of Erythrophleum fordii has been recorded recently, but its microsymbionts have never been studied. To investigate the diversity and biogeography of rhizobia associated with this leguminous evergreen tree, root nodules were collected from the southern subtropical region of China. A total of 166 bacterial isolates were obtained from the nodules and characterized. In a PCR-based restriction fragment length polymorphism (RFLP) analysis of ribosomal intergenic sequences, the isolates were classified into 22 types within the genus Bradyrhizobium. Sequence analysis of 16S rRNA, ribosomal intergenic spacer (IGS), and the housekeeping genes recA and glnII classified the isolates into four groups: the Bradyrhizobium elkanii and Bradyrhizobium pachyrhizi groups, comprising the dominant symbionts, Bradyrhizobium yuanmingense, and an unclassified group comprising the minor symbionts. The nodC and nifH phylogenetic trees defined five or six lineages among the isolates, which was largely consistent with the definition of genomic species. The phylogenetic results and evolutionary analysis demonstrated that mutation and vertical transmission of genes were the principal processes for the divergent evolution of Bradyrhizobium species associated with E. fordii, while lateral transfer and recombination of housekeeping and symbiotic genes were rare. The distribution of the dominant rhizobial populations was affected by soil pH and effective phosphorus. This is the first report to characterize E. fordii rhizobia. PMID:25085491

  20. Genetic diversity and evolution of Bradyrhizobium populations nodulating Erythrophleum fordii, an evergreen tree indigenous to the southern subtropical region of China.

    PubMed

    Yao, Yao; Wang, Rui; Lu, Jun Kun; Sui, Xin Hua; Wang, En Tao; Chen, Wen Xin

    2014-10-01

    The nodulation of Erythrophleum fordii has been recorded recently, but its microsymbionts have never been studied. To investigate the diversity and biogeography of rhizobia associated with this leguminous evergreen tree, root nodules were collected from the southern subtropical region of China. A total of 166 bacterial isolates were obtained from the nodules and characterized. In a PCR-based restriction fragment length polymorphism (RFLP) analysis of ribosomal intergenic sequences, the isolates were classified into 22 types within the genus Bradyrhizobium. Sequence analysis of 16S rRNA, ribosomal intergenic spacer (IGS), and the housekeeping genes recA and glnII classified the isolates into four groups: the Bradyrhizobium elkanii and Bradyrhizobium pachyrhizi groups, comprising the dominant symbionts, Bradyrhizobium yuanmingense, and an unclassified group comprising the minor symbionts. The nodC and nifH phylogenetic trees defined five or six lineages among the isolates, which was largely consistent with the definition of genomic species. The phylogenetic results and evolutionary analysis demonstrated that mutation and vertical transmission of genes were the principal processes for the divergent evolution of Bradyrhizobium species associated with E. fordii, while lateral transfer and recombination of housekeeping and symbiotic genes were rare. The distribution of the dominant rhizobial populations was affected by soil pH and effective phosphorus. This is the first report to characterize E. fordii rhizobia. PMID:25085491

  1. Theoretical Explanation of the Lotus Effect: Superhydrophobic Property Changes by Removal of Nanostructures from the Surface of a Lotus Leaf.

    PubMed

    Yamamoto, Minehide; Nishikawa, Naoki; Mayama, Hiroyuki; Nonomura, Yoshimune; Yokojima, Satoshi; Nakamura, Shinichiro; Uchida, Kingo

    2015-07-01

    Theoretical study is presented on the wetting behaviors of water droplets over a lotus leaf. Experimental results are interpreted to clarify the trade-offs among the potential energy change, the local pinning energy, and the adhesion energy. The theoretical parameters, calculated from the experimental results, are used to qualitatively explain the relations among surface fractal dimension, surface morphology, and dynamic wetting behaviors. The surface of a lotus leaf, which shows the superhydrophobic lotus effect, was dipped in ethanol to remove the plant waxes. As a result, the lotus effect is lost. The contact angle of a water drop decreased dramatically from 161° of the original surface to 122°. The water droplet was pinned on the surface. From the fractal analysis, the fractal region of the original surface was divided into two regions: a smaller-sized roughness region of 0.3-1.7 μm with D of 1.48 and a region of 1.7-19 μm with D of 1.36. By dipping the leaf in ethanol, the former fractal region, characterized by wax tubes, was lost, and only the latter large fractal region remained. The lotus effect is attributed to a surface structure that is covered with needle-shaped wax tubes, and the remaining surface allows invasion of the water droplet and enlarges the interaction with water. PMID:26075949

  2. The Role of Flavonoids in Nodulation Host-Range Specificity: An Update.

    PubMed

    Liu, Cheng-Wu; Murray, Jeremy D

    2016-01-01

    Flavonoids are crucial signaling molecules in the symbiosis between legumes and their nitrogen-fixing symbionts, the rhizobia. The primary function of flavonoids in the interaction is to induce transcription of the genes for biosynthesis of the rhizobial signaling molecules called Nod factors, which are perceived by the plant to allow symbiotic infection of the root. Many legumes produce specific flavonoids that only induce Nod factor production in homologous rhizobia, and therefore act as important determinants of host range. Despite a wealth of evidence on legume flavonoids, relatively few have proven roles in rhizobial infection. Recent studies suggest that production of key "infection" flavonoids is highly localized at infection sites. Furthermore, some of the flavonoids being produced at infection sites are phytoalexins and may have a role in the selection of compatible symbionts during infection. The molecular details of how flavonoid production in plants is regulated during nodulation have not yet been clarified, but nitrogen availability has been shown to play a role. PMID:27529286

  3. Molecular and Biochemical Characterization of the Parvulin-Type PPIases in Lotus japonicus1[C][W][OA

    PubMed Central

    Kouri, Evangelia D.; Labrou, Nikolaos E.; Garbis, Spiros D.; Kalliampakou, Katerina I.; Stedel, Catalina; Dimou, Maria; Udvardi, Michael K.; Katinakis, Panagiotis; Flemetakis, Emmanouil

    2009-01-01

    The cis/trans isomerization of the peptide bond preceding proline is an intrinsically slow process, although important in many biological processes in both prokaryotes and eukaryotes. In vivo, this isomerization is catalyzed by peptidyl-prolyl cis/trans-isomerases (PPIases). Here, we present the molecular and biochemical characterization of parvulin-type PPIase family members of the model legume Lotus japonicus, annotated as LjPar1, LjPar2, and LjPar3. Although LjPar1 and LjPar2 were found to be homologous to PIN1 (Protein Interacting with NIMA)-type parvulins and hPar14 from human, respectively, LjPar3 represents a novel multidomain parvulin, apparently present only in plants, that contains an active carboxyl-terminal sulfurtransferase domain. All Lotus parvulins were heterologously expressed and purified from Escherichia coli, and purified protein verification measurements used a liquid chromatography-mass spectrometry-based proteomic method. The biochemical characterization of the recombinant Lotus parvulins revealed that they possess PPIase activity toward synthetic tetrapeptides, although they exhibited different substrate specificities depending on the amino acid amino terminal to proline. These differences were also studied in a structural context using molecular modeling of the encoded polypeptides. Real-time reverse transcription-polymerase chain reaction revealed that the three parvulin genes of Lotus are ubiquitously expressed in all plant organs. LjPar1 was found to be up-regulated during the later stages of nodule development. Subcellular localization of LjPar-enhanced Yellow Fluorescence Protein (eYFP) fusions expressed in Arabidopsis (Arabidopsis thaliana) leaf epidermal cells revealed that LjPar1- and LjPar2-eYFP fusions were localized in the cytoplasm and in the nucleus, in contrast to LjPar3-eYFP, which was clearly localized in plastids. Divergent substrate specificities, expression profiles, and subcellular localization indicate that plant

  4. Recovery of symbiotic nitrogen fixing acacia rhizobia from Merzouga Desert sand dunes in South East Morocco--Identification of a probable new species of Ensifer adapted to stressed environments.

    PubMed

    Sakrouhi, Ilham; Belfquih, Meryem; Sbabou, Laïla; Moulin, Patricia; Bena, Gilles; Filali-Maltouf, Abdelkarim; Le Quéré, Antoine

    2016-03-01

    Bacteria capable of nodulating Acacia tortilis and A. gummifera could be recovered from sand dunes collected in the Moroccan Merzouga desert. The trapping approach enabled the recovery of 17 desert rhizobia that all clustered within the Ensifer (Sinorhizobium) genus. Four isolates of the dominant genotype comprising 15 strains as well as 2 divergent strains were further characterized by MLSA. Phylogenetic analyzes indicated that the dominant genetic type was belonging to a new and yet undefined species within the Ensifer genus. Interestingly, housekeeping gene phylogenies showed that this possibly new species is also present in another desert but in India. Phylogenetic analyses of nifH and nodC sequences showed high sequence conservation among the Moroccan strains belonging to the dominant genotype but high divergence with sequences from Indian isolates suggesting acquisition of symbiotic genes through Horizontal Gene Transfer. These desert rhizobia were capable of growing in media containing high salt concentrations, under high pH and most of the strains showed growth at 45°C. Only recovered from desert type of Biome, yet, this new taxon appears particularly adapted to such harsh environment. PMID:26867773

  5. Vigna unguiculata is nodulated in Spain by endosymbionts of Genisteae legumes and by a new symbiovar (vignae) of the genus Bradyrhizobium.

    PubMed

    Bejarano, Ana; Ramírez-Bahena, Martha-Helena; Velázquez, Encarna; Peix, Alvaro

    2014-10-01

    Vigna unguiculata was introduced into Europe from its distribution centre in Africa, and it is currently being cultivated in Mediterranean regions with adequate edapho-climatic conditions where the slow growing rhizobia nodulating this legume have not yet been studied. Previous studies based on rrs gene and ITS region analyses have shown that Bradyrhizobium yuanmingense and B. elkanii nodulated V. unguiculata in Africa, but these two species were not found in this study. Using the same phylogenetic markers it was shown that V. unguiculata, a legume from the tribe Phaseolae, was nodulated in Spain by two species of group I, B. cytisi and B. canariense, which are common endosymbionts of Genisteae in both Europe and Africa. These species have not been found to date in V. unguiculata nodules in its African distribution centres. All strains from Bradyrhizobium group I isolated in Spain belonged to the symbiovar genistearum, which is found at present only in Genisteae legumes in both Africa and Europe. V. unguiculata was also nodulated in Spain by a strain from Bradyrhizobium group II that belonged to a novel symbiovar (vignae). Some African V. unguiculata-nodulating strains also belonged to this proposed new symbiovar. PMID:24867807

  6. Mathematical Ecology Analysis of Geographical Distribution of Soybean-Nodulating Bradyrhizobia in Japan

    PubMed Central

    Saeki, Yuichi; Shiro, Sokichi; Tajima, Toshiyuki; Yamamoto, Akihiro; Sameshima-Saito, Reiko; Sato, Takashi; Yamakawa, Takeo

    2013-01-01

    We characterized the relationship between the genetic diversity of indigenous soybean-nodulating bradyrhizobia from weakly acidic soils in Japan and their geographical distribution in an ecological study of indigenous soybean rhizobia. We isolated bradyrhizobia from three kinds of Rj-genotype soybeans. Their genetic diversity and community structure were analyzed by PCR-RFLP analysis of the 16S–23S rRNA gene internal transcribed spacer (ITS) region with 11 Bradyrhizobium USDA strains as references. We used data from the present study and previous studies to carry out mathematical ecological analyses, multidimensional scaling analysis with the Bray-Curtis index, polar ordination analysis, and multiple regression analyses to characterize the relationship between soybean-nodulating bradyrhizobial community structures and their geographical distribution. The mathematical ecological approaches used in this study demonstrated the presence of ecological niches and suggested the geographical distribution of soybean-nodulating bradyrhizobia to be a function of latitude and the related climate, with clusters in the order Bj123, Bj110, Bj6, and Be76 from north to south in Japan. PMID:24240318

  7. The LBM program at the EPFL/LOTUS Facility

    SciTech Connect

    File, J.; Jassby, D.L.; Tsang, F.Y.; Haldy, P.A.; Leo, W.R.; Woodruff, G.

    1986-11-01

    An experimental program of neutron transport studies of the Lithium Blanket Module (LBM) is being carried out with the LOTUS point-neutron source facility at Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland. Preliminary experiments use passive neutron dosimetry within the fuel rods in the LBM central zone, as well as, both thermal extraction and dissolution methods to assay tritium bred in Li/sub 2/O diagnostic wafers and LBM pellets. These measurements are being compared and reconciled with each other and with the predictions of two-dimensional discrete-ordinates and continuous-energy Monte-Carlo analyses of the Lotus/LBM system.

  8. A high-throughput RNA interference (RNAi)-based approach using hairy roots for the study of plant-rhizobia interactions.

    PubMed

    Sinharoy, Senjuti; Pislariu, Catalina I; Udvardi, Michael K

    2015-01-01

    Legumes are major contributors to sustainable agriculture; their key feature is their ability to fix atmospheric nitrogen through symbiotic nitrogen fixation. Legumes are often recalcitrant to regeneration and transformation by Agrobacterium tumefaciens; however, A. rhizogenes-mediated root transformation and composite plant generation are rapid and convenient alternatives to study root biology, including root nodule symbiosis. RNA interference (RNAi), coupled with A. rhizogenes-mediated root transformation, has been very successfully used for analyses of gene function by reverse genetics. Besides being applied to model legumes (Medicago truncatula and Lotus japonicus), this method has been adopted for several other legumes due to the ease and relative speed with which transgenic roots can be generated. Several protocols for hairy root transformation have been published. Here we describe an improved hairy root transformation protocol and the methods to study nodulation in Medicago. We also highlight the major differences between our protocol and others, and key steps that need to be adjusted in order to translate this method to other legumes. PMID:25740364

  9. [Characteristics of Natural Selection in Populations of Nodule Bacteria (Rhizobium leguminosarum) Interacting With Different Host Plants].

    PubMed

    Andronov, E E; Igolkina, A A; Kimeklis, A K; Vorobyov, N I; Provorov, N A

    2015-10-01

    Using high throughput sequencing of the nodA gene, we studied the population dynamics of Rhizobium leguminosarum (bv. viciae, bv. trifolii) in rhizospheric and nodular subpopulations associated with the leguminous plants representing different cross-inoculation groups (Vicia sativa, Lathyrus pratensis of the vetch/vetchling/pea group and Trifolium hybridum of the clover group). The "rhizosphere-nodules" transitions result in either an increase or decrease in the frequencies of 10 of the 23 operational taxonomic units (OTUs) (which were identified with 95% similarity) depending on the symbiotic specificity and phylogenetic positions of OTUs. Statistical and bioinformatical analysis of the population structures suggest that the type of natural selection responsible for these changes may be diversifying at the whole-population level and frequency-dependent at the OTU-specific level, ensuring the divergent evolution of rhizobia interacting with different host species. PMID:27169225

  10. [Benign solitary thyroid nodule (BSTN)].

    PubMed

    Pencea, V; Tiron, V; Zbranca, E; Dudeanu, I; Baran, T; Dobrescu, G; Lazăr, C; Dolinescu, C; Strat, V

    1982-01-01

    Out of a series of 210 patients (193 women and 17 men) with BSTN, 62% presented an warm nodule, 25.2% a hot nodule and 11.9% a cold nodule. The highest incidence of the nodule was noticed round the age of 40-50 years. The most common site was the middle and lower area of the right thyroid lobe. The thyroid scintigram provided orientative data regarding the nature of BSTN, the treatment indication being the surgical intervention. Histopathologically, polymorphic aspects ranging from anizofollicular adenoma, adenomatous proliferations areas and hyperfunctional aspect to degenerative sclerous alterations and lymphoplasmocitary infiltrations were noticed. The current hypotheses regarding the etiopathogeny of nodule forming process are discussed. Based on some data in the literature, we consider the nodularization of the thyroid gland as a reactional zone functional desynchronization in the conditions of some great variations of the iodate intaxe. PMID:25588244

  11. Decoupled genomic elements and the evolution of partner quality in nitrogen-fixing rhizobia.

    PubMed

    Gordon, Benjamin R; Klinger, Christie R; Weese, Dylan J; Lau, Jennifer A; Burke, Patricia V; Dentinger, Bryn T M; Heath, Katy D

    2016-03-01

    Understanding how mutualisms evolve in response to a changing environment will be critical for predicting the long-term impacts of global changes, such as increased N (nitrogen) deposition. Bacterial mutualists in particular might evolve quickly, thanks to short generation times and the potential for independent evolution of plasmids through recombination and/or HGT (horizontal gene transfer). In a previous work using the legume/rhizobia mutualism, we demonstrated that long-term nitrogen fertilization caused the evolution of less-mutualistic rhizobia. Here, we use our 63 previously isolated rhizobium strains in comparative phylogenetic and quantitative genetic analyses to determine the degree to which variation in partner quality is attributable to phylogenetic relationships among strains versus recent genetic changes in response to N fertilization. We find evidence of distinct evolutionary relationships between chromosomal and pSym genes, and broad similarity between pSym genes. We also find that nifD has a unique evolutionary history that explains much of the variation in partner quality, and suggest MoFe subunit interaction sites in the evolution of less-mutualistic rhizobia. These results provide insight into the mechanisms behind the evolutionary response of rhizobia to long-term N fertilization, and we discuss the implications of our results for the evolution of the mutualism. PMID:27087920

  12. Selective medium for recovering specific populations of rhizobia introduced into tropical soils.

    PubMed

    Habte, M

    1985-12-01

    Experiments were designed to evaluate the usefulness of antifungal agents and streptomycin for recovering low densities of rhizobia inoculated into tropical soils. The results showed that yeast-mannitol agar (pH 6.0) containing 500 mug of streptomycin, 400 mug of cycloheximide and 50 mug of benomyl or chlorothalonil per ml was the best selective medium. PMID:16346957

  13. A JAZ Protein in Astragalus sinicus Interacts with a Leghemoglobin through the TIFY Domain and Is Involved in Nodule Development and Nitrogen Fixation.

    PubMed

    Li, Yixing; Xu, Meng; Wang, Ning; Li, Youguo

    2015-01-01

    Leghemoglobins (Lbs) play an important role in legumes-rhizobia symbiosis. Lbs bind O2 and protect nitrogenase activity from damage by O2 in nodules, therefore, they are regarded as a marker of active nitrogen fixation in nodules. Additionally, Lbs are involved in the nitric oxide (NO) signaling pathway, acting as a NO scavenger during nodule development and nitrogen fixation. However, regulators responsible for Lb expression and modulation of Lb activity have not been characterized. In our previous work, a Jasmonate-Zim-domain (JAZ) protein interacting with a Lb (AsB2510) in Astragalus sinicus was identified and designated AsJAZ1. In this study, the interaction between AsJAZ1 and AsB2510 was verified using a yeast two-hybrid system and in vitro Glutathione S-transferase (GST) pull-down assays, resulting in identification of the interaction domain as a TIFY (previously known as zinc-finger protein expressed in inflorescence meristem, ZIM) domain. TIFY domain is named after the most conserved amino acids within the domain. Bimolecular fluorescence complementation (BiFC) was used to confirm the interaction between AsJAZ1 and AsB2510 in tobacco cells, demonstrating that AsJAZ1-AsB2510 interaction was localized to the cell membrane and cytoplasm. Furthermore, the expression patterns and the symbiotic phenotypes of AsJAZ1 were investigated. Knockdown of AsJAZ1 expression via RNA interference led to decreased number of nodules, abnormal development of bacteroids, accumulation of poly-x-hydroxybutyrate (PHB) and loss of nitrogenase activity. Taken together, our results suggest that AsJAZ1 interacts with AsB2510 and participates in nodule development and nitrogen fixation. Our results provide novel insights into the functions of Lbs or JAZ proteins during legume-rhizobia symbiosis. PMID:26460857

  14. A JAZ Protein in Astragalus sinicus Interacts with a Leghemoglobin through the TIFY Domain and Is Involved in Nodule Development and Nitrogen Fixation

    PubMed Central

    Li, Yixing; Xu, Meng; Wang, Ning; Li, Youguo

    2015-01-01

    Leghemoglobins (Lbs) play an important role in legumes-rhizobia symbiosis. Lbs bind O2 and protect nitrogenase activity from damage by O2 in nodules, therefore, they are regarded as a marker of active nitrogen fixation in nodules. Additionally, Lbs are involved in the nitric oxide (NO) signaling pathway, acting as a NO scavenger during nodule development and nitrogen fixation. However, regulators responsible for Lb expression and modulation of Lb activity have not been characterized. In our previous work, a Jasmonate-Zim-domain (JAZ) protein interacting with a Lb (AsB2510) in Astragalus sinicus was identified and designated AsJAZ1. In this study, the interaction between AsJAZ1 and AsB2510 was verified using a yeast two-hybrid system and in vitro Glutathione S-transferase (GST) pull-down assays, resulting in identification of the interaction domain as a TIFY (previously known as zinc-finger protein expressed in inflorescence meristem, ZIM) domain. TIFY domain is named after the most conserved amino acids within the domain. Bimolecular fluorescence complementation (BiFC) was used to confirm the interaction between AsJAZ1 and AsB2510 in tobacco cells, demonstrating that AsJAZ1-AsB2510 interaction was localized to the cell membrane and cytoplasm. Furthermore, the expression patterns and the symbiotic phenotypes of AsJAZ1 were investigated. Knockdown of AsJAZ1 expression via RNA interference led to decreased number of nodules, abnormal development of bacteroids, accumulation of poly-x-hydroxybutyrate (PHB) and loss of nitrogenase activity. Taken together, our results suggest that AsJAZ1 interacts with AsB2510 and participates in nodule development and nitrogen fixation. Our results provide novel insights into the functions of Lbs or JAZ proteins during legume-rhizobia symbiosis. PMID:26460857

  15. Genetic divergence and gene flow among Mesorhizobium strains nodulating the shrub legume Caragana.

    PubMed

    Ji, Zhaojun; Yan, Hui; Cui, Qingguo; Wang, Entao; Chen, Wenxin; Chen, Wenfeng

    2015-05-01

    Although the biogeography of rhizobia has been investigated extensively, little is known about the adaptive molecular evolution of rhizobia influenced by soil environments and selected by legumes. In this study, microevolution of Mesorhizobium strains nodulating Caragana in a semi-fixing desert belt in northern China was investigated. Five core genes-atpD, glnII, gyrB, recA, and rpoB, six heat-shock factor genes-clpA, clpB, dnaK, dnaJ, grpE, and hlsU, and five nodulation genes-nodA, nodC, nodD, nodG, and nodP, of 72 representative mesorhizobia were studied in order to determine their genetic variations. A total of 21 genospecies were defined based on the average nucleotide identity (ANI) of concatenated core genes using a threshold of 96% similarity, and by the phylogenetic analyses of the core/heat-shock factor genes. Significant genetic divergence was observed among the genospecies in the semi-fixing desert belt (areas A-E) and Yunnan province (area F), which was closely related to the environmental conditions and geographic distance. Gene flow occurred more frequently among the genospecies in areas A-E, and three sites in area B, than between area F and the other five areas. Recombination occurred among strains more frequently for heat-shock factor genes than the other genes. The results conclusively showed that the Caragana-associated mesorhizobia had divergently evolved according to their geographic distribution, and have been selected not only by the environmental conditions but also by the host plants. PMID:25864639

  16. NADPH recycling systems in oxidative stressed pea nodules: a key role for the NADP+ -dependent isocitrate dehydrogenase.

    PubMed

    Marino, Daniel; González, Esther M; Frendo, Pierre; Puppo, Alain; Arrese-Igor, Cesar

    2007-01-01

    The symbiosis between legumes and rhizobia is characterised by the formation of dinitrogen-fixing root nodules. In natural conditions, nitrogen fixation is strongly impaired by abiotic stresses which generate over-production of reactive oxygen species. Since one of the nodule main antioxidant systems is the ascorbate-glutathione cycle, NADPH recycling that is involved in glutathione reduction is of great relevance under stress conditions. NADPH is mainly produced by glucose 6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (6PGDH; EC 1.1.1.44) from the oxidative pentose phosphate pathway, and also by NADP(+)-dependent isocitrate dehydrogenase (ICDH; EC 1.1.1.42). In this work, 10 microM paraquat (PQ) was applied to pea roots in order to determine the in vivo relationship between oxidative stress and the activity of the NADPH-generating enzymes in nodules. Whereas G6PDH and 6PGDH activities remained unchanged, a remarkable induction of ICDH gene expression and a dramatic increase of the ICDH activity was observed during the PQ treatment. These results support that ICDH has a key role in NADPH recycling under oxidative stress conditions in pea root nodules. PMID:16896792

  17. Antiinflammatory and analgesic activities of Zizyphus lotus root barks.

    PubMed

    Borgi, W; Ghedira, K; Chouchane, N

    2007-01-01

    The root barks of Zizyphus lotus were extracted with water, chloroform, ethyl acetate and methanol to determine their antiinflammatory and analgesic activities. Aqueous extract (50, 100 and 200 mg/kg) given intraperitoneally (i.p.) showed a significant and dose-dependent antiinflammatory and analgesic activity. PMID:17107758

  18. LOTUS 1-2-3 Macros for Library Applications.

    ERIC Educational Resources Information Center

    Howden, Norman

    1987-01-01

    Describes LOTUS 1-2-3, an advanced spreadsheet with database and text manipulation functions that can be used with microcomputers by librarians to provide customized calculation and data acquisition tools. Macro commands and the menu system are discussed, and an example is given of an invoice procedure. (Author/LRW)

  19. Technique for rapid establishment of American lotus in remediation efforts

    SciTech Connect

    Ryon, M. G.; Jett, R. T.; McCracken, M. K.; Morris, G. W.; Roy, W. K.; Fortner, A. M.; Goins, K. N.; Riazi, A. S.

    2013-03-01

    A technique for increasing the establishment rate of American lotus (Nelumbo lutea) and simplifying planting was developed as part of a pond remediation project. Lotus propagation techniques typically require scarification of the seed, germination in heated water, and planting in nursery containers. Then mature (~ 1 yr) nursery-grown stock is transferred to planting site or scarified seed are broadcast applied. Mature plants should grow more quickly, but can be sensitive to handling, require more time to plant, and cost more. Scarified seeds are easier to plant and inexpensive, but have a lag time in growth, can fail to germinate, and can be difficult to site precisely. We developed an intermediate technique using small burlap bags that makes planting easier, provides greater germination success, and avoids lag time in growth. Data on survival and growth from experiments using mature stock, scarified seeds, and bag lotus demonstrate that bag lotus grow rapidly in a variety of conditions, have a high survival rate, can be processed and planted easily and quickly, and are very suitable for a variety of remediation projects

  20. Graphing Online Searches with Lotus 1-2-3.

    ERIC Educational Resources Information Center

    Persson, Olle

    1986-01-01

    This article illustrates how Lotus 1-2-3 software can be used to create graphs using downloaded online searches as raw material, notes most commands applied, and outlines three required steps: downloading, importing the downloading file into the worksheet, and making graphs. An example in bibliometrics and sample graphs are included. (EJS)

  1. Welcome to Lotus 1-2-3. Learning Activity Packets.

    ERIC Educational Resources Information Center

    Mills, Steven; And Others

    This learning activity packet (LAP) contains 11 self-paced study lessons that allow students to proceed along a 36-hour course of study for Lotus 1-2-3 at their own pace. The lessons are organized in the following way: objectives, completion and performance standards, a list of required materials, unit test, and exercises (applications of the…

  2. Flower thermoregulation facilitates fertilization in Asian sacred lotus

    PubMed Central

    Li, Jiao-Kun; Huang, Shuang-Quan

    2009-01-01

    Background and Aims The thermoregulatory flower of the Asian sacred lotus (Nelumbo nucifera) can maintain a relatively stable temperature despite great variations in ambient temperature during anthesis. The thermoregulation has been hypothesized to offer a direct energy reward for pollinators in lotus flowers. This study aims to examine whether the stable temperature maintained in the floral chamber influences the fertilization process and seed development. Methods An artificial refrigeration instrument was employed to cool flowers during the fertilization process and post-fertilization period in an experimental population. The effect of temperature on post-pollination events was also examined by removing petals in two field populations. Key Results Treatments with low floral temperature did not reduce stigma receptivity or pollen viability in undehisced anthers. Low temperature during the fertilization period significantly decreased seed set per flower but low temperature during the phase of seed development had no effect, suggesting that temperature regulation by lotus flowers facilitated fertilization success. Hand-pollination treatments in two field populations indicated that seed set of flowers with petals removed was lower than that of intact flowers in north China, where ambient temperatures are low, but not in south China, confirming that reducing the temperature of carpels did influence post-pollination events. Conclusions The experiments suggest that floral thermoregulation in lotus could enhance female reproductive success by facilitating fertilization. PMID:19282320

  3. Neutronic analysis for the LBM/LOTUS experiment

    SciTech Connect

    Kolibal, J.; Ku, L.P.; Liew, S.L.

    1986-01-01

    The LBM/LOTUS experimental results will be compared with the calculated values using the MCC in early 1986 based on the MCNP and DOT models described. The comparison will allow a testing of the features of the MCC in a simplified situation, in preparation for the ultimate experiment of the LBM on TFTR.

  4. Lotus Notes in Action: Meeting Corporate Information Needs.

    ERIC Educational Resources Information Center

    Bates, Mary Ellen; Allen, Kimberly

    1994-01-01

    Discusses applications of Lotus Notes groupware developed by MCI Communications Corporation librarians. The development of administrative databases used for reference request tracking, interlibrary loan, book ordering and other purposes, and corporate wide databases used to disseminate internal and external information are described. The strengths…

  5. MicroRNA167-Directed Regulation of the Auxin Response Factors GmARF8a and GmARF8b Is Required for Soybean Nodulation and Lateral Root Development.

    PubMed

    Wang, Youning; Li, Kexue; Chen, Liang; Zou, Yanmin; Liu, Haipei; Tian, Yinping; Li, Dongxiao; Wang, Rui; Zhao, Fang; Ferguson, Brett J; Gresshoff, Peter M; Li, Xia

    2015-07-01

    Legume root nodules convert atmospheric nitrogen gas into ammonium through symbiosis with a prokaryotic microsymbiont broadly called rhizobia. Auxin signaling is required for determinant nodule development; however, the molecular mechanism of auxin-mediated nodule formation remains largely unknown. Here, we show in soybean (Glycine max) that the microRNA miR167 acts as a positive regulator of lateral root organs, namely nodules and lateral roots. miR167c expression was up-regulated in the vasculature, pericycle, and cortex of soybean roots following inoculation with Bradyrhizobium japonicum strain USDA110 (the microsymbiont). It was found to positively regulate nodule numbers directly by repressing the target genes GmARF8a and GmARF8b (homologous genes of Arabidopsis [Arabidopsis thaliana] AtARF8 that encode auxin response factors). Moreover, the expression of miR167 and its targets was up- and down-regulated by auxin, respectively. The miR167-GmARF8 module also positively regulated nodulation efficiency under low microsymbiont density, a condition often associated with environmental stress. The regulatory role of miR167 on nodule initiation was dependent on the Nod factor receptor GmNFR1α, and it acts upstream of the nodulation-associated genes nodule inception, nodulation signaling pathway1, early nodulin40-1, NF-YA1 (previously known as HAEM activator protein2-1), and NF-YA2. miR167 also promoted lateral root numbers. Collectively, our findings establish a key role for the miR167-GmARF8 module in auxin-mediated nodule and lateral root formation in soybean. PMID:25941314

  6. Proof that Burkholderia Strains Form Effective Symbioses with Legumes: a Study of Novel Mimosa-Nodulating Strains from South America

    PubMed Central

    Chen, Wen-Ming; de Faria, Sergio M.; Straliotto, Rosângela; Pitard, Rosa M.; Simões-Araùjo, Jean L.; Chou, Jui-Hsing; Chou, Yi-Ju; Barrios, Edmundo; Prescott, Alan R.; Elliott, Geoffrey N.; Sprent, Janet I.; Young, J. Peter W.; James, Euan K.

    2005-01-01

    Twenty Mimosa-nodulating bacterial strains from Brazil and Venezuela, together with eight reference Mimosa-nodulating rhizobial strains and two other β-rhizobial strains, were examined by amplified rRNA gene restriction analysis. They fell into 16 patterns and formed a single cluster together with the known β-rhizobia, Burkholderia caribensis, Burkholderia phymatum, and Burkholderia tuberum. The 16S rRNA gene sequences of 15 of the 20 strains were determined, and all were shown to belong to the genus Burkholderia; four distinct clusters could be discerned, with strains isolated from the same host species usually clustering very closely. Five of the strains (MAP3-5, Br3407, Br3454, Br3461, and Br3469) were selected for further studies of the symbiosis-related genes nodA, the NodD-dependent regulatory consensus sequences (nod box), and nifH. The nodA and nifH sequences were very close to each other and to those of B. phymatum STM815, B. caribensis TJ182, and Cupriavidus taiwanensis LMG19424 but were relatively distant from those of B. tuberum STM678. In addition to nodulating their original hosts, all five strains could also nodulate other Mimosa spp., and all produced nodules on Mimosa pudica that had nitrogenase (acetylene reduction) activities and structures typical of effective N2-fixing symbioses. Finally, both wild-type and green fluorescent protein-expressing transconjugant strains of Br3461 and MAP3-5 produced N2-fixing nodules on their original hosts, Mimosa bimucronata (Br3461) and Mimosa pigra (MAP3-5), and hence this confirms strongly that Burkholderia strains can form effective symbioses with legumes. PMID:16269788

  7. Allograft pancreas: pale acinar nodules.

    PubMed

    Troxell, Megan L; Drachenberg, Cinthia

    2016-08-01

    Microscopic pale-staining acinar nodules were characterized in native pancreas in the 1980s under a variety of names but have been infrequently reported since. We retrospectively studied the frequency and characteristics of pale acinar nodules in allograft pancreas biopsies, as compared to a sampling of native pancreas specimens at our center. Pale acinar nodules were present in 13% (9/69) of allograft biopsies from 22% (7/32) of transplant patients, and 23% (5/22) of native pancreas surgical specimens, although more nodules per pancreas area were present in allograft needle biopsies. Acinar nodules had size of 100 to 700 μm, were periodic acid-Schiff pale, were synaptophysin negative, stained more weakly with keratin CAM 5.2 compared to surrounding parenchyma, and had a low proliferative rate. Ultrastructural evaluation revealed paucity of zymogen granules with dilated cistern-like structures. In our experience, pale acinar nodules have similar features in allograft and native pancreas specimens, yet remain of uncertain etiology and significance. PMID:27063474

  8. Cartilage Acidic Protein–1B (LOTUS), an Endogenous Nogo Receptor Antagonist for Axon Tract Formation

    PubMed Central

    Sato, Yasufumi; Iketani, Masumi; Kurihara, Yuji; Yamaguchi, Megumi; Yamashita, Naoya; Nakamura, Fumio; Arie, Yuko; Kawasaki, Takahiko; Hirata, Tatsumi; Abe, Takaya; Kiyonari, Hiroshi; Strittmatter, Stephen M.; Goshima, Yoshio; Takei, Kohtaro

    2011-01-01

    Neural circuitry formation depends on the molecular control of axonal projection during development. By screening with fluorophore-assisted light inactivation in the developing mouse brain, we identified cartilage acidic protein–1B as a key molecule for lateral olfactory tract (LOT) formation and named it LOT usher substance (LOTUS). We further identified Nogo receptor–1 (NgR1) as a LOTUS-binding protein. NgR1 is a receptor of myelin-derived axon growth inhibitors, such as Nogo, which prevent neural regeneration in the adult. LOTUS suppressed Nogo-NgR1 binding and Nogo-induced growth cone collapse. A defasciculated LOT was present in lotus-deficient mice but not in mice lacking both lotus- and ngr1. These findings suggest that endogenous antagonism of NgR1 by LOTUS is crucial for normal LOT formation. PMID:21817055

  9. Genome-wide Medicago truncatula small RNA analysis revealed novel microRNAs and isoforms differentially regulated in roots and nodules.

    PubMed

    Lelandais-Brière, Christine; Naya, Loreto; Sallet, Erika; Calenge, Fanny; Frugier, Florian; Hartmann, Caroline; Gouzy, Jérome; Crespi, Martin

    2009-09-01

    Posttranscriptional regulation of a variety of mRNAs by small 21- to 24-nucleotide RNAs, notably the microRNAs (miRNAs), is emerging as a novel developmental mechanism. In legumes like the model Medicago truncatula, roots are able to develop a de novo meristem through the symbiotic interaction with nitrogen-fixing rhizobia. We used deep sequencing of small RNAs from root apexes and nodules of M. truncatula to identify 100 novel candidate miRNAs encoded by 265 hairpin precursors. New atypical precursor classes producing only specific 21- and 24-nucleotide small RNAs were found. Statistical analysis on sequencing reads abundance revealed specific miRNA isoforms in a same family showing contrasting expression patterns between nodules and root apexes. The differentially expressed conserved and nonconserved miRNAs may target a large variety of mRNAs. In root nodules, which show diverse cell types ranging from a persistent meristem to a fully differentiated central region, we discovered miRNAs spatially enriched in nodule meristematic tissues, vascular bundles, and bacterial infection zones using in situ hybridization. Spatial regulation of miRNAs may determine specialization of regulatory RNA networks in plant differentiation processes, such as root nodule formation. PMID:19767456

  10. MucR Is Required for Transcriptional Activation of Conserved Ion Transporters to Support Nitrogen Fixation of Sinorhizobium fredii in Soybean Nodules.

    PubMed

    Jiao, Jian; Wu, Li Juan; Zhang, Biliang; Hu, Yue; Li, Yan; Zhang, Xing Xing; Guo, Hui Juan; Liu, Li Xue; Chen, Wen Xin; Zhang, Ziding; Tian, Chang Fu

    2016-05-01

    To achieve effective symbiosis with legume, rhizobia should fine-tune their background regulation network in addition to activating key genes involved in nodulation (nod) and nitrogen fixation (nif). Here, we report that an ancestral zinc finger regulator, MucR1, other than its paralog, MucR2, carrying a frameshift mutation, is essential for supporting nitrogen fixation of Sinorhizobium fredii CCBAU45436 within soybean nodules. In contrast to the chromosomal mucR1, mucR2 is located on symbiosis plasmid, indicating its horizontal transfer potential. A MucR2 homolog lacking the frameshift mutation, such as the one from S. fredii NGR234, can complement phenotypic defects of the mucR1 mutant of CCBAU45436. RNA-seq analysis revealed that the MucR1 regulon of CCBAU45436 within nodules exhibits significant difference compared with that of free-living cells. MucR1 is required for active expression of transporters for phosphate, zinc, and elements essential for nitrogenase activity (iron, molybdenum, and sulfur) in nodules but is dispensable for transcription of key genes (nif/fix) involved in nitrogen fixation. Further reverse genetics suggests that S. fredii uses high-affinity transporters to meet the demand for zinc and phosphate within nodules. These findings, together with the horizontal transfer potential of the mucR homolog, imply an intriguing evolutionary role of this ancestral regulator in supporting nitrogen fixation. PMID:26883490

  11. Antigenic changes in lipopolysaccharide I of Rhizobium leguminosarum bv. viciae in root nodules of Vicia sativa subsp. nigra occur during release from infection threads.

    PubMed Central

    Goosen-de Roo, L; de Maagd, R A; Lugtenberg, B J

    1991-01-01

    Three different monoclonal antibodies raised against the O antigen-containing lipopolysaccharide (LPS I) of free-living cells were used in an immunocytochemical study to follow the fate of LPS I on the outer membrane of Rhizobium leguminosarum bv. viciae 248 during the nodulation of Vicia sativa subsp. nigra. After immunogold labeling, the LPS I epitopes were detected on the outer membrane of bacteria present in infection threads throughout the nodule. Epitopes were not detectable on bacteria released from the infection thread. The data show that the LPS I epitopes present on rhizobia in infection droplets disappear shortly before or during endocytosis of the bacteria into the host plant cell cytoplasm. The abruptness of the change suggests an active degradation or modification of LPS I epitopes rather than only a repression of their synthesis. Images PMID:1708764

  12. Regulation of nonsymbiotic and truncated hemoglobin genes of Lotus japonicus in plant organs and in response to nitric oxide and hormones.

    PubMed

    Bustos-Sanmamed, Pilar; Tovar-Méndez, Alejandro; Crespi, Martin; Sato, Shusei; Tabata, Satoshi; Becana, Manuel

    2011-02-01

    • In legumes, symbiotic leghemoglobins facilitate oxygen diffusion to the bacteroids, but the roles of nonsymbiotic and truncated hemoglobins are largely unknown. Here the five hemoglobin genes of Lotus japonicus have been functionally characterized to gain insight into their regulatory mechanisms. • Plants were exposed to nitric oxide donors, stressful conditions, and hormones. Gene expression profiling was determined by quantitative PCR, and gene activities were localized using in situ hybridization and promoter-reporter gene fusions. • The LjGLB1-1, LjGLB2, and LjGLB3-1 mRNA expression levels were very high in nodules relative to other plant organs. The expression of these genes was localized in the vascular bundles, cortex, and infected tissue. LjGLB1-1 was the only gene induced by nitric oxide. Cytokinins caused nearly complete inactivation of LjGLB2 and LjGLB3-1 in nodules and induction of LjGLB1-1 in roots. Abscisic acid induced LjGLB1-1 in nodules and LjGLB1-2 and LjGLB2 in roots, whereas polyamines and jasmonic acid induced LjGLB1-1 only in roots. • The enhanced expression of the three types of hemoglobins in nodules, the colocalization of gene activities in nodule and root tissues with high metabolic rates, and their distinct regulatory mechanisms point out complementary roles of hemoglobins and strongly support the hypothesis that LjGLB1-1, LjGLB2, and LjGLB3-1 are required for symbiosis. PMID:21073469

  13. Fractal Surfaces of Molecular Crystals Mimicking Lotus Leaf with Phototunable Double Roughness Structures.

    PubMed

    Nishimura, Ryo; Hyodo, Kengo; Sawaguchi, Haruna; Yamamoto, Yoshiaki; Nonomura, Yoshimune; Mayama, Hiroyuki; Yokojima, Satoshi; Nakamura, Shinichiro; Uchida, Kingo

    2016-08-17

    Double roughness structure, the origin of the lotus effect of natural lotus leaf, was successfully reproduced on a diarylethene microcrystalline surface. Static superwater-repellency and dynamic water-drop-bouncing were observed on the surface, in the manner of natural lotus leaves. Double roughness structure was essential for water-drop-bouncing. This ability was not observed on a single roughness microcrystalline surface showing the lotus effect of the same diarylethene derivative. The double roughness structure was reversibly controlled by alternating irradiation with UV and visible light. PMID:27455376

  14. Establishment of the Lotus japonicus Gene Expression Atlas (LjGEA) and its use to explore legume seed maturation.

    PubMed

    Verdier, Jerome; Torres-Jerez, Ivone; Wang, Mingyi; Andriankaja, Andry; Allen, Stacy N; He, Ji; Tang, Yuhong; Murray, Jeremy D; Udvardi, Michael K

    2013-04-01

    Lotus japonicus is a model species for legume genomics. To accelerate legume functional genomics, we developed a Lotus japonicus Gene Expression Atlas (LjGEA), which provides a global view of gene expression in all organ systems of this species, including roots, nodules, stems, petioles, leaves, flowers, pods and seeds. Time-series data covering multiple stages of developing pod and seed are included in the LjGEA. In addition, previously published L. japonicus Affymetrix data are included in the database, making it a 'one-stop shop' for transcriptome analysis of this species. The LjGEA web server (http://ljgea.noble.org/) enables flexible, multi-faceted analyses of the transcriptome. Transcript data may be accessed using the Affymetrix probe identification number, DNA sequence, gene name, functional description in natural language, and GO and KEGG annotation terms. Genes may be discovered through co-expression or differential expression analysis. Users may select a subset of experiments and visualize and compare expression profiles of multiple genes simultaneously. Data may be downloaded in a tabular form compatible with common analytical and visualization software. To illustrate the power of LjGEA, we explored the transcriptome of developing seeds. Genes represented by 36 474 probe sets were expressed at some stage during seed development, and almost half of these genes displayed differential expression during development. Among the latter were 624 transcription factor genes, some of which are orthologs of transcription factor genes that are known to regulate seed development in other species, while most are novel and represent attractive targets for reverse genetics approaches to determine their roles in this important organ. PMID:23452239

  15. Selective Medium for Recovering Specific Populations of Rhizobia Introduced into Tropical Soils †

    PubMed Central

    Habte, Mitiku

    1985-01-01

    Experiments were designed to evaluate the usefulness of antifungal agents and streptomycin for recovering low densities of rhizobia inoculated into tropical soils. The results showed that yeast-mannitol agar (pH 6.0) containing 500 μg of streptomycin, 400 μg of cycloheximide and 50 μg of benomyl or chlorothalonil per ml was the best selective medium. PMID:16346957

  16. Phytochemical profile and antimicrobial properties of Lotus spp. (Fabaceae).

    PubMed

    Girardi, Felipe A; Tonial, Fabiana; Chini, Silvia O; Sobottka, Andréa M; Scheffer-Basso, Simone M; Bertol, Charise D

    2014-09-01

    The phytochemical profile and antimicrobial activity of cultivar (cv.) extracts of Lotus uliginosus (cvs. Trojan and Serrano), L. tenuis (cv. Larrañaga) and L. corniculatus (cv. São Gabriel) were investigated. The phytochemical analysis revealed tannins, coumarins and flavonoids in all extracts, with variations among cultivars, showing genotypic variability. By High Performance Liquid Chromatographic method, the cvs. Larrañaga and São Gabriel showed the highest percentage of catechin and epicatechin, respectively, and presented rutin, which was not detected in the other ones. These genotypes showed antifungal activity but not antibacterial one. The cv. Larrañaga inhibited the mycelia growth of Alternaria sp. and Fusarium graminearum while the cv. São Gabriel was active only against Alternaria sp. The cultivars showed the greatest amounts of secondary metabolites and demonstrated significant activity against filamentous fungi. The results provide a direction for further research about pharmacological use of Lotus spp. PMID:25014916

  17. Lotus Dust Mitigation Coating and Molecular Adsorber Coating

    NASA Technical Reports Server (NTRS)

    O'Connor, Kenneth M.; Abraham, Nithin S.

    2015-01-01

    NASA Goddard Space Flight Center has developed two unique coating formulations that will keep surfaces clean and sanitary and contain contaminants.The Lotus Dust Mitigation Coating, modeled after the self-cleaning, water-repellant lotus leaf, disallows buildup of dust, dirt, water, and more on surfaces. This coating, has been successfully tested on painted, aluminum, glass, silica, and some composite surfaces, could aid in keeping medical assets clean.The Molecular Adsorber Coating is a zeolite-based, sprayable molecular adsorber coating, designed to prevent outgassing in materials in vacuums. The coating works well to adsorb volatiles and contaminates in manufacturing and processing, such as in pharmaceutical production. The addition of a biocide would also aid in controlling bacteria levels.

  18. Metabolic Activity and Population Dynamics of Rhizobia Introduced into Unamended and Bentonite-Amended Loamy Sand

    PubMed Central

    Heijnen, C. E.; Burgers, S. L. G. E.; Veen, J. A. Van

    1993-01-01

    Respiration measurements showed that the cumulative amount of CO2 respired by rhizobia introduced into sterile bentonite-amended loamy sand was significantly higher than it was in unamended loamy sand. The maintenance respiration of rhizobial cells was not influenced by the presence of bentonite clay. Carbon was used more efficiently during growth in bentonite-amended than in unamended loamy sand. The presence of bentonite clay increased the growth rate of rhizobia introduced into sterile soil. Survival studies performed in nonsterile bentonite-amended loamy sand showed that the use of high (1010 cells per g of dry soil) rather than lower (104 to 107 cells per g of dry soil) inoculum densities increased the final survival levels of introduced rhizobia. In unamended loamy sand, the application of 1010 or 107 cells per g of dry soil resulted in similar final survival levels. Pore shape and the continuity of the water-filled pore system were suggested to largely determine the colonization rate of protective microhabitats. PMID:16348889

  19. A rare cause of gastrointestinal phytobezoars: diospyros lotus

    PubMed Central

    2012-01-01

    Aim Diospyros Lotus (“Wild Date Palm of Trabzon or Persimmon”), which has been proven to cause phytobezoars, is a widely consumed fruit in the Black Sea and Northeast Anatolia regions of Turkey. The aim of the present study was to investigate the effects of Diospyros Lotus together with other predisposing factors, on the development of gastrointestinal phytobezoars and to discuss the treatment results in comparison to the literature. Material and method The records of 13 patients, who had been admitted to the General Surgery Clinic of Düzce Atatürk State Hospital between August 2008 and August 2011, were retrospectively reviewed. Demographic characteristics, predisposing factors, clinical and radiological findings, diagnostic and therapeutic methods, and the outcomes of the patients were recorded from the patient files. Written informed consent was obtained from each patient for publication of this research article and accompanying images. Results All the patients had a history of consuming Diospyros Lotus. Of the patients, 30,7% had a history of previous gastric surgery, 30,7% had diabetes mellitus and 23% had dental implants. None of the patients had hypothyroidism, which is another predisposing factor for phytobezoars. The phytobezoars were located in the stomach alone in 23% of the patients, whereas 15,3% was detected in the jejunum and stomach, 15,3% was detected in the jejunum alone, and 46,1% was detected in the ileum alone. All patients were treated with surgery, and there were no deaths. Conclusion Gastric phytobezoars are rare. Preventive measures have particular importance in the management of this condition, which is difficult to treat. For this purpose, excessive consumption of herbal nutrients containing a high amount of indigestible fibers such as Diospyros Lotus should be avoided in patients with a history of gastrointestinal surgery or poor oral and dental health. PMID:22721161

  20. Positioning the nodule, the hormone dictum

    PubMed Central

    Ding, Yiliang

    2009-01-01

    The formation of a nitrogen-fixing nodule involves two diverse developmental processes in the legume root: infection thread initiation in epidermal cells and nodule primordia formation in the cortex. Several plant hormones have been reported to positively or negatively regulate nodulation. These hormones function at different stages in the nodulation process and may facilitate the coordinated development of the epidermal and cortical developmental programs that are necessary to allow bacterial infection into the developing nodule. In this paper, we review and discuss how the tissue specific nature of hormonal action dictates where, when and how a nodule is formed. PMID:19649179

  1. Positioning the nodule, the hormone dictum.

    PubMed

    Ding, Yiliang; Oldroyd, Giles E D

    2009-02-01

    The formation of a nitrogen-fixing nodule involves two diverse developmental processes in the legume root: infection thread initiation in epidermal cells and nodule primordia formation in the cortex. Several plant hormones have been reported to positively or negatively regulate nodulation. These hormones function at different stages in the nodulation process and may facilitate the coordinated development of the epidermal and cortical developmental programs that are necessary to allow bacterial infection into the developing nodule. In this paper, we review and discuss how the tissue specific nature of hormonal action dictates where, when and how a nodule is formed. PMID:19649179

  2. New Nodule-Newer Etiology

    PubMed Central

    Mehta, Atul C; Wang, Juan; Abuqayyas, Sami; Garcha, Puneet; Lane, Charles Randy; Tsuang, Wayne; Budev, Marie; Akindipe, Olufemi

    2016-01-01

    AIM: To evaluate frequency and temporal relationship between pulmonary nodules (PNs) and transbronchial biopsy (TBBx) among lung transplant recipients (LTR). METHODS: We retrospectively reviewed 100 records of LTR who underwent flexible bronchoscopy (FB) with TBBx, looking for the appearance of peripheral pulmonary nodule (PPN). If these patients had chest radiographs within 50 d of FB, they were included in the study. Data was compared with 30 procedures performed among non-transplant patients. Information on patient’s demographics, antirejection medications, anticoagulation, indication and type of lung transplantation, timing of the FB and the appearance and disappearance of the nodules and its characteristics were gathered. RESULTS: Nineteen new PN were found in 13 procedures performed on LTR and none among non-transplant patients. Nodules were detected between 4-47 d from the procedure and disappeared within 84 d after appearance without intervention. CONCLUSION: FB in LTR is associated with development of new, transient PPN at the site of TBBx in 13% of procedures. We hypothesize that these nodules are related to local hematoma and impaired lymphatic drainage. Close observation is a reasonable management approach. PMID:27011920

  3. Extra-slow-growing Tardiphaga strains isolated from nodules of Vavilovia formosa (Stev.) Fed.

    PubMed

    Safronova, Vera I; Kuznetsova, Irina G; Sazanova, Anna L; Kimeklis, Anastasiia K; Belimov, Andrey A; Andronov, Evgeny E; Pinaev, Alexander G; Pukhaev, Andrey R; Popov, Konstantin P; Akopian, Janna A; Willems, Anne; Tikhonovich, Igor A

    2015-09-01

    Eleven extra-slow-growing strains were isolated from nodules of the relict legume Vavilovia formosa growing in North Ossetia (Caucasus) and Armenia. All isolates formed a single rrs cluster together with the type strain Tardiphaga robiniae LMG 26467(T), while the sequencing of the 16S-23S rDNA intergenic region (ITS) and housekeeping genes glnII, atpD, dnaK, gyrB, recA and rpoB divided them into three groups. North Ossetian isolates (in contrast to the Armenian ones) were clustered separately from the type strain LMG 26467(T). However, all isolates were classified as T. robiniae because the DNA-DNA relatedness between them and the type strain LMG 26467(T) was 69.6% minimum. Two symbiosis-related genes (nodM and nodT) were amplified in all isolated Tardiphaga strains. It was shown that the nodM gene phylogeny is similar to that of ITS and housekeeping genes. The presence of the other symbiosis-related genes in described Tardiphaga strains, which is recently described genus of rhizobia, as well as their ability to form nodules on any plants are under investigation. PMID:26013968

  4. Glycolysis and the Tricarboxylic Acid Cycle Are Linked by Alanine Aminotransferase during Hypoxia Induced by Waterlogging of Lotus japonicus1[W][OA

    PubMed Central

    Rocha, Marcio; Licausi, Francesco; Araújo, Wagner L.; Nunes-Nesi, Adriano; Sodek, Ladaslav; Fernie, Alisdair R.; van Dongen, Joost T.

    2010-01-01

    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 metabolism in combination with the modular operation of a split tricarboxylic acid pathway. The sum result of this metabolic scenario is the accumulation of alanine and succinate and the production of extra ATP under hypoxia. The importance of alanine metabolism is discussed with respect to its ability to regulate the level of pyruvate, and this and all other changes are discussed in the context of current models concerning the regulation of plant metabolism. PMID:20089769

  5. 78 FR 39062 - Group Lotus plc; Modification of a Temporary Exemption From an Advanced Air Bag Requirement of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-28

    ... small manufacturers such as Lotus as of September 1, 2012. \\1\\ 78 FR 15114. After publication of Lotus's... exemption, in control of the company's dealers. See 60 FR 12281 (Mar. 6, 1995). The 50 vehicles will count... National Highway Traffic Safety Administration Group Lotus plc; Modification of a Temporary Exemption...

  6. Stress tolerance, genetic analysis and symbiotic properties of root-nodulating bacteria isolated from Mediterranean leguminous shrubs in Central Spain.

    PubMed

    Ruiz-Díez, Beatriz; Fajardo, Susana; Puertas-Mejía, Miguel Angel; de Felipe, María del Rosario; Fernández-Pascual, Mercedes

    2009-01-01

    Nine root-nodulating bacterial isolates were obtained from the leguminous shrubs Spartium junceum, Adenocarpus hispanicus, Cytisus purgans, Cytisus laburnuum, Retama sphaerocarpa and Colutea arborescens in areas of Central Spain. A poliphasic approach analyzing phenotypic, symbiotic and genetic properties was used to study their diversity and characterize them in relation to Mediterranean conditions. Stress tolerance assays revealed marked variations in salinity, extreme pH and cadmium tolerance compared with reference strains, with the majority showing salinity, alkalinity and Cd tolerance and three of them growing at acid pH. Variation within the 16S rRNA gene was examined by amplified 16S rDNA restriction analysis (ARDRA) and direct sequencing to show genetic diversity. Phylogeny confirmed the close relationship of four isolates with Bradyrhizobium canariense, three with Phylobacterium myrsinacearum, one with Rhizobium rhizogenes and another with Mesorhizobium huakuii. The cross inoculation tests revealed wide spectra of nodulation. This is the first report of P. myrsinacearum being able to nodulate these leguminous shrubs, and also the first time reported the association between B.canariense, R. rhizogenes and M. huakuii and C. laburnuum, C. purgans and C. arborescens, respectively. These results suggested that native rhizobia could be suitable candidates as biofertilizers and/or inoculants of leguminous shrubs with restoration or revegetation purposes in Mediterranean areas. PMID:18784916

  7. Diary of a Conversion--Lotus 1-2-3 to Symphony 1.1.

    ERIC Educational Resources Information Center

    Dunnewin, Larry

    1986-01-01

    Describes the uses of Lotus 1-2-3 (a spreadsheet-graphics-database program created by Lotus Development Corporation) and Symphony 1.1 (a refinement and expansion of Symphony 1.01 providing memory efficiency, speed, ease of use, greater file compatibility). Spreadsheet and graphics capabilities, the use of windows, database environment, and…

  8. Isolated Rheumatoid Nodule of the Achilles.

    PubMed

    Spicer, Paul J; Broussard, Gerald; Beaman, Francesca

    2016-06-01

    Approximately 20% to 25% of patients with rheumatoid arthritis have rheumatoid nodules. These nodules most commonly involve the soft tissues of the upper extremity, particularly adjacent to the olecranon. We present an uncommon case of a solitary rheumatoid nodule arising from the paratenon of the Achilles tendon with ultrasound and magnetic resonance images. PMID:26086458

  9. LOTUS-DB: an integrative and interactive database for Nelumbo nucifera study

    PubMed Central

    Wang, Kun; Deng, Jiao; Damaris, Rebecca Njeri; Yang, Mei; Xu, Liming; Yang, Pingfang

    2015-01-01

    Besides its important significance in plant taxonomy and phylogeny, sacred lotus (Nelumbo nucifera Gaertn.) might also hold the key to the secrets of aging, which attracts crescent attentions from researchers all over the world. The genetic or molecular studies on this species depend on its genome information. In 2013, two publications reported the sequencing of its full genome, based on which we constructed a database named as LOTUS-DB. It will provide comprehensive information on the annotation, gene function and expression for the sacred lotus. The information will facilitate users to efficiently query and browse genes, graphically visualize genome and download a variety of complex data information on genome DNA, coding sequence (CDS), transcripts or peptide sequences, promoters and markers. It will accelerate researches on gene cloning, functional identification of sacred lotus, and hence promote the studies on this species and plant genomics as well. Database URL: http://lotus-db.wbgcas.cn. PMID:25819075

  10. LOTUS-DB: an integrative and interactive database for Nelumbo nucifera study.

    PubMed

    Wang, Kun; Deng, Jiao; Damaris, Rebecca Njeri; Yang, Mei; Xu, Liming; Yang, Pingfang

    2015-01-01

    Besides its important significance in plant taxonomy and phylogeny, sacred lotus (Nelumbo nucifera Gaertn.) might also hold the key to the secrets of aging, which attracts crescent attentions from researchers all over the world. The genetic or molecular studies on this species depend on its genome information. In 2013, two publications reported the sequencing of its full genome, based on which we constructed a database named as LOTUS-DB. It will provide comprehensive information on the annotation, gene function and expression for the sacred lotus. The information will facilitate users to efficiently query and browse genes, graphically visualize genome and download a variety of complex data information on genome DNA, coding sequence (CDS), transcripts or peptide sequences, promoters and markers. It will accelerate researches on gene cloning, functional identification of sacred lotus, and hence promote the studies on this species and plant genomics as well. Database URL: http://lotus-db.wbgcas.cn PMID:25819075

  11. Evaluation of the thyroid nodule

    SciTech Connect

    Cannon, C.R.

    1986-05-01

    Evaluation of thyroid nodules challenges the most astute clinician. The history and the physical examination often identify those patients who require immediate surgical management. In other patients, time-honored thyroid function studies and thyroid scanning are helpful. Fine needle aspiration and computed tomography are also valuable in the diagnostic work-up.

  12. Rhizobium taibaishanense sp. nov., isolated from a root nodule of Kummerowia striata.

    PubMed

    Yao, Li Juan; Shen, Yao Yao; Zhan, Jun Peng; Xu, Wei; Cui, Guang Ling; Wei, Ge Hong

    2012-02-01

    During a study of the diversity and phylogeny of rhizobia in the root nodules of Kummerowia striata grown in north-western China, four strains were classified in the genus Rhizobium on the basis of their 16S rRNA gene sequences. The 16S rRNA gene sequences of three of these strains were identical and that of the other strain, which was the only one isolated in Yangling, differed from the others by just 1 bp. The16S rRNA gene sequences of the four strains showed a mean similarity of 99.3 % with the most closely related, recognized species, Rhizobium vitis. The corresponding recA and glnA gene sequences showed similarities with established species of Rhizobium of less than 86.5 % and less than 89.6 %, respectively. These low similarities indicated that the four strains represented a novel species of the genus Rhizobium. The strains were also found to be distinguishable from the closest related, established species (R. vitis) by rep-PCR DNA fingerprinting, analysis of cellular fatty acid profiles and from the results of a series of phenotypic tests. The level of DNA-DNA relatedness between the representative strain CCNWSX 0483(T) and Rhizobium vitis IAM 14140(T) was only 40.13 %. Therefore, a novel species, Rhizobium taibaishanense sp. nov., is proposed, with strain CCNWSX 0483(T) ( = ACCC 14971(T) = HAMBI 3214(T)) as the type strain. In nodulation and pathogenicity tests, none of the four strains of Rhizobium taibaishanense sp. nov. was able to induce any nodule or tumour formation on plants. As no amplicons were detected when DNA from the strains was run in PCR with primers for the detection of nodA, nifH and virC gene sequences, the strains probably do not carry sym or vir genes. PMID:21421926

  13. Loss of the nodule-specific cysteine rich peptide, NCR169, abolishes symbiotic nitrogen fixation in the Medicago truncatula dnf7 mutant

    PubMed Central

    Horváth, Beatrix; Domonkos, Ágota; Szűcs, Attila; Ábrahám, Edit; Ayaydin, Ferhan; Bóka, Károly; Chen, Yuhui; Chen, Rujin; Murray, Jeremy D.; Udvardi, Michael K.; Kondorosi, Éva; Kaló, Péter

    2015-01-01

    Host compatible rhizobia induce the formation of legume root nodules, symbiotic organs within which intracellular bacteria are present in plant-derived membrane compartments termed symbiosomes. In Medicago truncatula nodules, the Sinorhizobium microsymbionts undergo an irreversible differentiation process leading to the development of elongated polyploid noncultivable nitrogen fixing bacteroids that convert atmospheric dinitrogen into ammonia. This terminal differentiation is directed by the host plant and involves hundreds of nodule specific cysteine-rich peptides (NCRs). Except for certain in vitro activities of cationic peptides, the functional roles of individual NCR peptides in planta are not known. In this study, we demonstrate that the inability of M. truncatula dnf7 mutants to fix nitrogen is due to inactivation of a single NCR peptide, NCR169. In the absence of NCR169, bacterial differentiation was impaired and was associated with early senescence of the symbiotic cells. Introduction of the NCR169 gene into the dnf7-2/NCR169 deletion mutant restored symbiotic nitrogen fixation. Replacement of any of the cysteine residues in the NCR169 peptide with serine rendered it incapable of complementation, demonstrating an absolute requirement for all cysteines in planta. NCR169 was induced in the cell layers in which bacteroid elongation was most pronounced, and high expression persisted throughout the nitrogen-fixing nodule zone. Our results provide evidence for an essential role of NCR169 in the differentiation and persistence of nitrogen fixing bacteroids in M. truncatula. PMID:26401023

  14. Loss of the nodule-specific cysteine rich peptide, NCR169, abolishes symbiotic nitrogen fixation in the Medicago truncatula dnf7 mutant.

    PubMed

    Horváth, Beatrix; Domonkos, Ágota; Kereszt, Attila; Szűcs, Attila; Ábrahám, Edit; Ayaydin, Ferhan; Bóka, Károly; Chen, Yuhui; Chen, Rujin; Murray, Jeremy D; Udvardi, Michael K; Kondorosi, Éva; Kaló, Péter

    2015-12-01

    Host compatible rhizobia induce the formation of legume root nodules, symbiotic organs within which intracellular bacteria are present in plant-derived membrane compartments termed symbiosomes. In Medicago truncatula nodules, the Sinorhizobium microsymbionts undergo an irreversible differentiation process leading to the development of elongated polyploid noncultivable nitrogen fixing bacteroids that convert atmospheric dinitrogen into ammonia. This terminal differentiation is directed by the host plant and involves hundreds of nodule specific cysteine-rich peptides (NCRs). Except for certain in vitro activities of cationic peptides, the functional roles of individual NCR peptides in planta are not known. In this study, we demonstrate that the inability of M. truncatula dnf7 mutants to fix nitrogen is due to inactivation of a single NCR peptide, NCR169. In the absence of NCR169, bacterial differentiation was impaired and was associated with early senescence of the symbiotic cells. Introduction of the NCR169 gene into the dnf7-2/NCR169 deletion mutant restored symbiotic nitrogen fixation. Replacement of any of the cysteine residues in the NCR169 peptide with serine rendered it incapable of complementation, demonstrating an absolute requirement for all cysteines in planta. NCR169 was induced in the cell layers in which bacteroid elongation was most pronounced, and high expression persisted throughout the nitrogen-fixing nodule zone. Our results provide evidence for an essential role of NCR169 in the differentiation and persistence of nitrogen fixing bacteroids in M. truncatula. PMID:26401023

  15. Cicer canariense, an endemic legume to the Canary Islands, is nodulated in mainland Spain by fast-growing strains from symbiovar trifolii phylogenetically related to Rhizobium leguminosarum.

    PubMed

    Martínez-Hidalgo, Pilar; Flores-Félix, José-David; Menéndez, Esther; Rivas, Raúl; Carro, Lorena; Mateos, Pedro F; Martínez-Molina, Eustoquio; León-Barrios, Milagros; Velázquez, Encarna

    2015-07-01

    Cicer canariense is a threatened endemic legume from the Canary Islands where it can be nodulated by mesorhizobial strains from the symbiovar ciceri, which is the common worldwide endosymbiont of Cicer arietinum linked to the genus Mesorhizobium. However, when C. canariense was cultivated in a soil from mainland Spain, where the symbiovar ciceri is present, only fast-growing rhizobial strains were unexpectedly isolated from its nodules. These strains were classified into the genus Rhizobium by analysis of the recA and atpD genes, and they were phylogenetically related to Rhizobium leguminosarum. The analysis of the nodC gene showed that the isolated strains belonged to the symbiovar trifolii that harbored a nodC allele (β allele) different to that harbored by other strains from this symbiovar. Nodulation experiments carried out with the lacZ-labeled strain RCCHU01, representative of the β nodC allele, showed that it induced curling of root hairs, infected them through infection threads, and formed typical indeterminate nodules where nitrogen fixation took place. This represents a case of exceptional performance between the symbiovar trifolii and a legume from the tribe Cicereae that opens up new possibilities and provides new insights into the study of rhizobia-legume symbiosis. PMID:26032249

  16. Development of functional symbiotic white clover root hairs and nodules requires tightly regulated production of rhizobial cellulase CelC2.

    PubMed

    Robledo, Marta; Jiménez-Zurdo, José I; Soto, M José; Velázquez, Encarnación; Dazzo, Frank; Martínez-Molina, Eustoquio; Mateos, Pedro F

    2011-07-01

    The establishment of rhizobia as nitrogen-fixing endosymbionts within legume root nodules requires the disruption of the plant cell wall to breach the host barrier at strategic infection sites in the root hair tip and at points of bacterial release from infection threads (IT) within the root cortex. We previously found that Rhizobium leguminosarum bv. trifolii uses its chromosomally encoded CelC2 cellulase to erode the noncrystalline wall at the apex of root hairs, thereby creating the primary portal of its entry into white clover roots. Here, we show that a recombinant derivative of R. leguminosarum bv. trifolii ANU843 that constitutively overproduces the CelC2 enzyme has increased competitiveness in occupying aberrant nodule-like root structures on clover that are inefficient in nitrogen fixation. This aberrant symbiotic phenotype involves an extensive uncontrolled degradation of the host cell walls restricted to the expected infection sites at tips of deformed root hairs and significantly enlarged infection droplets at termini of wider IT within the nodule infection zone. Furthermore, signs of elevated plant host defense as indicated by reactive oxygen species production in root tissues were more evident during infection by the recombinant strain than its wild-type parent. Our data further support the role of the rhizobial CelC2 cell wall-degrading enzyme in primary infection, and show evidence of its importance in secondary symbiotic infection and tight regulation of its production to establish an effective nitrogen-fixing root nodule symbiosis. PMID:21405987

  17. Occurrence of nodulation in unexplored leguminous trees native to the West African tropical rainforest and inoculation response of native species useful in reforestation.

    PubMed

    Diabate, Moussa; Munive, Antonio; de Faria, Sérgio Miana; Ba, Amadou; Dreyfus, Bernard; Galiana, Antoine

    2005-04-01

    Despite the abundance and diversity of timber tree legumes in the West African rainforest, their ability to form nitrogen-fixing nodules in symbiosis with rhizobia, and their response to rhizobial inoculation, remain poorly documented. In the first part of this study the occurrence of nodulation was determined in 156 leguminous species growing in six natural forest areas in Guinea, mostly mature trees. In the second part, an in situ experiment of rhizobial inoculation was performed on eight selected tree species belonging to three genera: Albizia, Erythrophleum and Millettia. Of the 97 plant species and 14 genera that had never been examined before this study, 31 species and four genera were reported to be nodulated. After 4 months of growing in a nursery and a further 11 months after transplantation of plants to the field, we observed a highly significant (P < 0.001) and positive effect of inoculation with Bradyrhizobium sp. strains on the growth of the eight tree species tested. The importance of determining the nodulation ability of unexplored local trees and subsequently using this information for inoculation in reforestation programmes was demonstrated. PMID:15760366

  18. Phytochelatin synthases of the model legume Lotus japonicus. A small multigene family with differential response to cadmium and alternatively spliced variants.

    PubMed

    Ramos, Javier; Clemente, Maria R; Naya, Loreto; Loscos, Jorge; Pérez-Rontomé, Carmen; Sato, Shusei; Tabata, Satoshi; Becana, Manuel

    2007-03-01

    The biosynthesis of phytochelatins and homophytochelatins has been studied in nodulated plants of the model legume Lotus (Lotus japonicus). In the first 6 to 24 h of treatment with cadmium (Cd), roots started to synthesize elevated amounts of both polypeptides, with a concomitant increase of glutathione and a decrease of homoglutathione, indicating the presence of active phytochelatin synthase (PCS) genes. Screening of transformation-competent artificial chromosome libraries allowed identification of a cluster of three genes, LjPCS1, LjPCS2, and LjPCS3, which were mapped at 69.0 cM on chromosome 1. The genes differ in exon-intron composition and responsiveness to Cd. Gene structures and phylogenetic analysis of the three protein products, LjPCS1-8R, LjPCS2-7N, and LjPCS3-7N, are consistent with two sequential gene duplication events during evolution of vascular plants. Two sites for alternative splicing in the primary transcripts were identified. One of them, involving intron 2 of the LjPCS2 gene, was confirmed by the finding of the two predicted mRNAs, encoding LjPCS2-7R in roots and LjPCS2-7N in nodules. The amino acid sequences of LjPCS2-7R (or LjPCS2-7N) and LjPCS3-7N share 90% identity, but have only 43% to 59% identity with respect to the typical PCS1 enzymes of Lotus and other plants. The unusual LjPCS2-7N and LjPCS3-7N proteins conferred Cd tolerance when expressed in yeast (Saccharomyces cerevisiae) cells, whereas the alternatively spliced form, LjPCS2-7R, differing only in a five-amino acid motif (GRKWK) did not. These results unveil complex regulatory mechanisms of PCS expression in legume tissues in response to heavy metals and probably to other developmental and environmental factors. PMID:17208961

  19. Phytochelatin Synthases of the Model Legume Lotus japonicus. A Small Multigene Family with Differential Response to Cadmium and Alternatively Spliced Variants1[OA

    PubMed Central

    Ramos, Javier; Clemente, Maria R.; Naya, Loreto; Loscos, Jorge; Pérez-Rontomé, Carmen; Sato, Shusei; Tabata, Satoshi; Becana, Manuel

    2007-01-01

    The biosynthesis of phytochelatins and homophytochelatins has been studied in nodulated plants of the model legume Lotus (Lotus japonicus). In the first 6 to 24 h of treatment with cadmium (Cd), roots started to synthesize elevated amounts of both polypeptides, with a concomitant increase of glutathione and a decrease of homoglutathione, indicating the presence of active phytochelatin synthase (PCS) genes. Screening of transformation-competent artificial chromosome libraries allowed identification of a cluster of three genes, LjPCS1, LjPCS2, and LjPCS3, which were mapped at 69.0 cM on chromosome 1. The genes differ in exon-intron composition and responsiveness to Cd. Gene structures and phylogenetic analysis of the three protein products, LjPCS1-8R, LjPCS2-7N, and LjPCS3-7N, are consistent with two sequential gene duplication events during evolution of vascular plants. Two sites for alternative splicing in the primary transcripts were identified. One of them, involving intron 2 of the LjPCS2 gene, was confirmed by the finding of the two predicted mRNAs, encoding LjPCS2-7R in roots and LjPCS2-7N in nodules. The amino acid sequences of LjPCS2-7R (or LjPCS2-7N) and LjPCS3-7N share 90% identity, but have only 43% to 59% identity with respect to the typical PCS1 enzymes of Lotus and other plants. The unusual LjPCS2-7N and LjPCS3-7N proteins conferred Cd tolerance when expressed in yeast (Saccharomyces cerevisiae) cells, whereas the alternatively spliced form, LjPCS2-7R, differing only in a five-amino acid motif (GRKWK) did not. These results unveil complex regulatory mechanisms of PCS expression in legume tissues in response to heavy metals and probably to other developmental and environmental factors. PMID:17208961

  20. Growth and survival of cowpea rhizobia in acid, aluminum-rich soils

    SciTech Connect

    Hartel, P.G.; Alexander, M.

    1983-01-01

    A study was undertaken to determine whether Al-sensitive cowpea Rhizobium survives in acid, Al-rich soils. The lower pH limit for growth of 20 strains in a defined liquid medium varied from pH 4.2 to less than pH 3.6. The mean lower limit for growth was pH 3.9. Several of the strains clumped in this medium at pH 4.5. Of 11 strains that were tested for tolerance to high levels of Al in a defined liquid medium at pH 4.5, nine tolerated 75 ..mu..M Al, and the other two were sensitive to levels above 15 ..mu..M. Three strains, one Al-tolerant, one Al-sensitive, and one Al-tolerant or Al-sensitive depending on the presence of vitamins in the medium, were selected for studies in Al-rich sterile and nonsterile soils. These rhizobia did not survive in soils of less than pH 4.7 sterilized by /sup 60/Co irradiation. When inoculated into sterile soil at pH 4.7, the consistently sensitive strain initially failed to proliferate and then grew slowly, but populations of the other two rhizobia increased rapidly. No consistent relationship was found between the Al tolerance of these three rhizobia and their growth and survival in four acid, Al-rich soils. The data suggest that Al is of minor importance to growth and survival of cowpea Rhizobium strains in acid soils. 16 references, 4 figures, 1 table.

  1. Invalidity of the Concept of Slow Growth and Alkali Production in Cowpea Rhizobia

    PubMed Central

    Hernandez, Blanca S.; Focht, Dennis D.

    1984-01-01

    A total of 103 rhizobial strains representing the cowpea miscellany and Rhizobium japonicum were studied with regard to growth rate, glucose metabolic pathways, and pH change in culture medium. Doubling times ranged from 1.4 ± 0.04 to 44.1 ± 5.2 h; although two populations of “fast-growing” and “slow-growing” rhizobia were noted, they overlapped and were not distinctly separated. Twenty-four strains which had doubling times of less than 8 h all showed NADP-linked 6-phosphogluconate dehydrogenase (6-PGD) activity, whereas only one slow-growing strain (doubling time, 10.8 ± 0.9 h) of all those tested showed 6-PGD activity. Doubling times among fast growers could not be explained solely by the presence or absence of 6-PGD activity (r2 = 0.14) because the tricarboxylic acid cycle and the Emden-Meyerhoff-Parnas pathway were operative in both 6-PGD-positive and 6-PGD-negative strains. Growth rate and pH change were unrelated to each other. Fast- or slow-growing strains were not associated with any particular legume species or group of species from which they were originally isolated, with the exception of Stylosanthes spp., all nine isolates of which were slow growers. We conclude that 6-PGD activity is a more distinctive characteristic among physiologically different groups of rhizobia than doubling times and that characterization of the cowpea rhizobia as slow-growing alkali producers is an invalid concept. PMID:16346589

  2. Increase of Natural 15N Enrichment of Soybean Nodules with Mean Nodule Mass 1

    PubMed Central

    Shearer, Georgia; Bryan, Barbara A.; Kohl, Daniel H.

    1984-01-01

    The 15N abundance of soybean (Glycine max L. Merrill var Harosoy) nodules is usually greater than it is for other tissues or for atmospheric N2. Results of experiments in which nodules were separated by size show that the magnitude of the 15N enrichment is correlated with nodule mass. The results support the hypothesis that 15N enrichment of nodules results from differential N isotopic fractionation for synthesis of nodule tissue versus synthesis of compounds for export from the nodule. The physiological significance of this hypothesis is that it requires that a substantial fraction of the N for nodule tissue synthesis in 15N-enriched nodules be N recently fixed within the same nodule. PMID:16663917

  3. Characterization of rhizobia from legumes of agronomic interest grown in semi-arid areas of Central Spain relates genetic differences to soil properties.

    PubMed

    Ruiz-Díez, Beatriz; Fajardo, Susana; Felipe, María del Rosario de; Fernández-Pascual, Mercedes

    2012-02-01

    A study of symbiotic bacteria from traditional agricultural legumes from Central Spain was performed to create a collection of rhizobia from soils differing in physicochemical, analytical and/or agroecological properties which could be well-adapted to the environmental conditions of this region, and be used for sustainable agricultural practices. Thirty-six isolates were obtained from root-nodules of fifteen legume species (including Cicer arietinum, Lathyrus sativus, Lens culinaris, Lupinus spp., Medicago sativa, Phaseolus vulgaris, Pisum sativum, and Vicia spp.) from three agriculture areas with soils of different pHs and from a forest area with undisturbed soils. Phenotypical characterization revealed uniformity across the thirty-six isolates, with important exceptions in terms of environmental tolerance (three isolates survived at high temperatures, three at high salinity and three at acid pH). The molecular analysis of 16S rRNA gene showed a close relationship of twenty-nine isolates to Rhizobium leguminosarum, one to Rhizobium gallicum, one to Mesorhizobium ciceri, two to Sinorhizobium (Ensifer) meliloti and three to Bradyrhizobium canariense. The sequence analysis of a symbiosis-specific gene, nod C, showed a correlation with the plant host and grouped twenty-six isolates with Rhizobium leguminosarum bv. viciae, establishing the diversity in relation to legume-host. The 16S-23S rRNA intergenic spacer (IGS) region allowed for intraspecific differentiation, so that strains with equal 16S rRNA were grouped by means of their soil origin. These results indicated that phenotypical and genetically related strains may be widely distributed in this region and that soil abiotic characteristics could have a substantial bearing on the selection of the strains living in each environment. PMID:21953333

  4. Automatic lung nodule classification with radiomics approach

    NASA Astrophysics Data System (ADS)

    Ma, Jingchen; Wang, Qian; Ren, Yacheng; Hu, Haibo; Zhao, Jun

    2016-03-01

    Lung cancer is the first killer among the cancer deaths. Malignant lung nodules have extremely high mortality while some of the benign nodules don't need any treatment .Thus, the accuracy of diagnosis between benign or malignant nodules diagnosis is necessary. Notably, although currently additional invasive biopsy or second CT scan in 3 months later may help radiologists to make judgments, easier diagnosis approaches are imminently needed. In this paper, we propose a novel CAD method to distinguish the benign and malignant lung cancer from CT images directly, which can not only improve the efficiency of rumor diagnosis but also greatly decrease the pain and risk of patients in biopsy collecting process. Briefly, according to the state-of-the-art radiomics approach, 583 features were used at the first step for measurement of nodules' intensity, shape, heterogeneity and information in multi-frequencies. Further, with Random Forest method, we distinguish the benign nodules from malignant nodules by analyzing all these features. Notably, our proposed scheme was tested on all 79 CT scans with diagnosis data available in The Cancer Imaging Archive (TCIA) which contain 127 nodules and each nodule is annotated by at least one of four radiologists participating in the project. Satisfactorily, this method achieved 82.7% accuracy in classification of malignant primary lung nodules and benign nodules. We believe it would bring much value for routine lung cancer diagnosis in CT imaging and provide improvement in decision-support with much lower cost.

  5. Transcriptome Response Mediated by Cold Stress in Lotus japonicus

    PubMed Central

    Calzadilla, Pablo I.; Maiale, Santiago J.; Ruiz, Oscar A.; Escaray, Francisco J.

    2016-01-01

    Members of the Lotus genus are important as agricultural forage sources under marginal environmental conditions given their high nutritional value and tolerance of various abiotic stresses. However, their dry matter production is drastically reduced in cooler seasons, while their response to such conditions is not well studied. This paper analyzes cold acclimation of the genus by studying Lotus japonicus over a stress period of 24 h. High-throughput RNA sequencing was used to identify and classify 1077 differentially expressed genes, of which 713 were up-regulated and 364 were down-regulated. Up-regulated genes were principally related to lipid, cell wall, phenylpropanoid, sugar, and proline regulation, while down-regulated genes affected the photosynthetic process and chloroplast development. Together, a total of 41 cold-inducible transcription factors were identified, including members of the AP2/ERF, NAC, MYB, and WRKY families; two of them were described as putative novel transcription factors. Finally, DREB1/CBFs were described with respect to their cold stress expression profiles. This is the first transcriptome profiling of the model legume L. japonicus under cold stress. Data obtained may be useful in identifying candidate genes for breeding modified species of forage legumes that more readily acclimate to low temperatures. PMID:27066029

  6. Metal matrix composites for sustainable lotus-effect surfaces.

    PubMed

    Nosonovsky, Michael; Hejazi, Vahid; Nyong, Aniedi E; Rohatgi, Pradeep K

    2011-12-01

    The lotus effect involving roughness-induced superhydrophobicity is a way to design nonwetting, self-cleaning, omniphobic, icephobic, and antifouling surfaces. However, such surfaces require micropatterning, which is extremely vulnerable to even small wear rates. This limits the applicability of the lotus effects to situations when wear is practically absent. To design sustainable superhydrophobic surfaces, we suggest using metal matrix composites (MMCs) with hydrophobic reinforcement in the bulk of the material, rather than only at its surface. Such surfaces, if properly designed, provide roughness and heterogeneity needed for superhydrophobicity. In addition, they are sustainable, since when the surface layer is deteriorated and removed due to wear, hydrophobic reinforcement and roughness remains. We present a model and experimental data on wetting of MMCs. We also conducted selected experiments with graphite-reinforced MMCs and showed that the contact angle can be determined from the model. In order to decouple the effects of reinforcement and roughness, the experiments were conducted for initially smooth and etched matrix and composite materials. PMID:21999807

  7. Nodule parenchyma-specific expression of the sesbania rostrata early nodulin gene SrEnod2 is mediated by its 3' untranslated region

    PubMed Central

    Chen, R; Silver, DL; de Bruijn FJ

    1998-01-01

    The early nodulin Enod2 gene encodes a putative hydroxyproline-rich cell wall protein and is expressed exclusively in the nodule parenchyma cell layer. The latter finding suggests that the Enod2 protein may contribute to the special morphological features of the nodule parenchyma and to the creation of an oxygen diffusion barrier. The Enod2 gene of the stem-nodulating legume Sesbania rostrata (SrEnod2) is induced specifically in roots by the plant hormone cytokinin, and this induction occurs at a post-transcriptional level. Here, we characterize the cis determinant(s) in the SrEnod2 locus responsible for nodule parenchyma-specific expression and show that the 3' untranslated region (UTR) of the SrEnod2 gene is both required and sufficient for directing chimeric reporter gene expression in the nodule parenchyma of transgenic Lotus corniculatus plants. Moreover, we show that the SrEnod2 3' UTR does not act as a tissue-specific enhancer element. By conducting a detailed deletion analysis of the 5' and 3' SrEnod2 regions, we delimited the minimal promoter of the SrEnod2 gene, and it appears that the 5' flanking sequences are not essential for nodule parenchyma-specific expression. This finding is in contrast with the report that the 5' upstream region of the soybean Enod2 gene directs nodule parenchyma-specific expression, indicating that different mechanisms may be involved in regulating the expression of these two genes. We definitively demonstrate that the cis element(s) for tissue-specific expression is located within the 3' UTR of a plant nuclear gene. PMID:9761788

  8. Rooting and acclimatization of micropropagated marubakaido apple rootstock using Adesmia latifolia rhizobia.

    PubMed

    Muniz, Aleksander Westphal; de Sá, Enilson Luiz; Dalagnol, Gilberto Luíz; Filho, João Américo

    2013-01-01

    In vitro rooting and the acclimatization of micropropagated rootstocks of apple trees is essential for plant development in the field. The aim of this work was to assess the use of rhizobia of Adesmia latifolia to promote rooting and acclimatization in micropropagated Marubakaido apple rootstock. An experiment involving in vitro rooting and acclimatization was performed with four strains of rhizobium and two controls, one with and the other without the addition of synthetic indoleacetic acid. The inoculated treatments involved the use of sterile inoculum and inoculum containing live rhizobia. The most significant effects on the rooting rate, primary-root length, number of roots, root length, fresh-shoot biomass, and fresh-root biomass were obtained by inoculation with strain EEL16010B and with synthetic indole acetic acid. However, there was no difference in the growth of apple explants in the acclimatization experiments. Strain EEL16010B can be used to induce in vitro rooting of the Marubakaido rootstock and can replace the use of synthetic indoleacetic acid in the rooting of this cultivar. PMID:24102038

  9. Solitary thyroid nodule. 1. Clinical characteristics

    SciTech Connect

    Mazzaferri, E.L.

    1981-07-01

    The approach to management of an isolated thyroid nodule requires some understanding of the natural history of thyroid cancer and other forms of nodular thyroid disease. The histologic classification of thyroid cancer is an important determinant of survival, as are the size of the primary tumor, presence of thyroid capsule invasion, and presence of distant metastases. Therapeutic radiation and radioactive fallout increase the risk that a thyroid nodule is malignant. Autonomously functioning thyroid nodules are usually benign follicular adenomas and may cause thyrotoxicosis.

  10. Effect of Microwave Irradiation on the Physicochemical and Digestive Properties of Lotus Seed Starch.

    PubMed

    Zeng, Shaoxiao; Chen, Bingyan; Zeng, Hongliang; Guo, Zebin; Lu, Xu; Zhang, Yi; Zheng, Baodong

    2016-03-30

    The objective of this study is to investigate the effect of microwave irradiation on the physicochemical and digestive properties of lotus seed starch. The physicochemical properties of lotus seed starch were characterized by light microscopy, (1)H NMR, FT-IR spectroscopy, and HPSEC-MALLS-RI. The starch-water interaction and crystalline region increased due to the changed water distribution of starch granules and the increase of the double-helix structure. The swelling power, amylose leaching, molecular properties, and radius of gyration reduced with the increasing microwave power, which further affected the sensitivity of lotus seed starch to enzymatic degradation. Furthermore, the resistant starch and slowly digestible starch increased with the increasing microwave irradiation, which further resulted in their decreasing hydrolysis index and glycemic index. The digestive properties of lotus seed starch were mainly influenced by the reduced branching degree of amylopectin and the strong amylose-amylose interaction. PMID:26912092

  11. The Use of Lotus 1-2-3 Macros in Engineering Calculations.

    ERIC Educational Resources Information Center

    Rosen, Edward M.

    1990-01-01

    Described are the use of spreadsheet programs in chemical engineering calculations using Lotus 1-2-3 macros. Discusses the macro commands, subroutine operations, and solution of partial differential equation. Provides examples of the subroutine programs and spreadsheet solution. (YP)

  12. Lotus leaf extract and L-carnitine influence different processes during the adipocyte life cycle

    PubMed Central

    2010-01-01

    Background The cellular and molecular mechanisms of adipose tissue biology have been studied extensively over the last two decades. Adipose tissue growth involves both an increase in fat cell size and the formation of mature adipocytes from precursor cells. To investigate how natural substances influence these two processes, we examined the effects of lotus leaf extract (Nelumbo nucifera-extract solution obtained from Silab, France) and L-carnitine on human preadipocytes and adipocytes. Methods For our in vitro studies, we used a lotus leaf extract solution alone or in combination with L-carnitine. Utilizing cultured human preadipocytes, we investigated lotus leaf extract solution-induced inhibition of triglyceride incorporation during adipogenesis and possible effects on cell viability. Studies on human adipocytes were performed aiming to elucidate the efficacy of lotus leaf extract solution to stimulate lipolytic activity. To further characterize lotus leaf extract solution-mediated effects, we determined the expression of the transcription factor adipocyte determination and differentiation factor 1 (ADD1/SREBP-1c) on the RNA- and protein level utilizing qRT-PCR and immunofluorescence analysis. Additionally, the effect of L-carnitine on beta-oxidation was analyzed using human preadipocytes and mature adipocytes. Finally, we investigated additive effects of a combination of lotus leaf extract solution and L-carnitine on triglyceride accumulation during preadipocyte/adipocyte differentiation. Results Our data showed that incubation of preadipocytes with lotus leaf extract solution significantly decreased triglyceride accumulation during adipogenesis without affecting cell viability. Compared to controls, adipocytes incubated with lotus leaf extract solution exhibited a significant increase in lipolysis-activity. Moreover, cell populations cultivated in the presence of lotus leaf extract solution showed a decrease in adipocyte differentiation capacity as indicated

  13. The Sinorhizobium meliloti ntrX Gene Is Involved in Succinoglycan Production, Motility, and Symbiotic Nodulation on Alfalfa

    PubMed Central

    Wang, Dong; Xue, Haiying; Wang, Yiwen; Yin, Ruochun; Xie, Fang

    2013-01-01

    Rhizobia establish a symbiotic relationship with their host legumes to induce the formation of nitrogen-fixing nodules. This process is regulated by many rhizobium regulators, including some two-component regulatory systems (TCSs). NtrY/NtrX, a TCS that was first identified in Azorhizobium caulinodans, is required for free-living nitrogen metabolism and symbiotic nodulation on Sesbania rostrata. However, its functions in a typical rhizobium such as Sinorhizobium meliloti remain unclear. Here we found that the S. meliloti response regulator NtrX but not the histidine kinase NtrY is involved in the regulation of exopolysaccharide production, motility, and symbiosis with alfalfa. A plasmid insertion mutant of ntrX formed mucous colonies, which overproduced succinoglycan, an exopolysaccharide, by upregulating its biosynthesis genes. This mutant also exhibited motility defects due to reduced flagella and decreased expression of flagellins and regulatory genes. The regulation is independent of the known regulatory systems of ExoR/ExoS/ChvI, EmmABC, and ExpR. Alfalfa plants inoculated with the ntrX mutant were small and displayed symptoms of nitrogen starvation. Interestingly, the deletion mutant of ntrY showed a phenotype similar to that of the parent strain. These findings demonstrate that the S. meliloti NtrX is a new regulator of succinoglycan production and motility that is not genetically coupled with NtrY. PMID:24038694

  14. Measurement and analysis of effective thermal conductivities of lotus-type porous copper

    NASA Astrophysics Data System (ADS)

    Ogushi, T.; Chiba, H.; Nakajima, H.; Ikeda, T.

    2004-05-01

    Lotus-type porous copper is a porous medium made of copper that contains many straight pores. To effectively employ lotus-type porous copper as a heat sink, it is necessary to clarify the pore effect on the thermal conductivity of lotus copper. This article describes an experimental and analytical investigation on the effective thermal conductivities of lotus copper parallel and perpendicular to the pores. The lotus copper displayed anisotropy of the effective thermal conductivity. The effective thermal conductivity keff⊥ perpendicular to the pores was lower than that of the parallel ones keff∥ and was 40% that of lotus copper material ks with porosity ɛ of 0.4. Experimental data for keff∥ showed good agreement with analytical results derived from the assumption that heat flow through the cross-sectional area parallel to the pore axis is proportional to (1-ɛ). Experimental data for keff⊥ showed good agreement with the analytical results derived from the assumption of orthorhombic symmetry and with the numerical results under a uniform staggered array with a nonuniform pore diameter.

  15. Photoprotective Effect of Lotus (Nelumbo nucifera Gaertn.) Seed Tea against UVB Irradiation

    PubMed Central

    Kim, Su-Yeon; Moon, Gap-Soon

    2015-01-01

    Lotus (Nelumbo nucifera Gaertn.) seed is widely used as a traditional medicine in countries of Asia. Among many functions of the lotus seed, one interesting activity is its skin protection from the sunlight and scar. In this study, we focused on the skin protective property of lotus seed tea against ultraviolet B (UVB) irradiation. Two groups of a hairless mouse model, water as control (water group) and lotus seed tea (LST group), were administrated a fluid drink water for six months. After 6 month of administration, UVB exposure was carried out to both groups for another 3 months. During and after the administration, the skin moisture content and the morphological and histopathological analyses through biopsy were carried out. Prior to UVB irradiation, no significant difference was discovered in the skin moisture content for the water group and LST group (P<0.05). However, drastic changes were observed after the UVB treatment. The LST group showed a clear evidence of skin protection compared to the control group (P<0.05). The moisture content, epidermal and horny layer thickness, and protein carbonyl values all revealed that the intake of the lotus seed tea enhanced protection against UVB exposure. As a result, the long-term intake of the lotus seed tea showed the effect of preventing loss of skin moisture, mitigating the formation of abnormal keratinocytes, and contributing to protein oxidation inhibition. PMID:26451352

  16. Genome-wide identification and characterization of GRAS transcription factors in sacred lotus (Nelumbo nucifera)

    PubMed Central

    Zhou, Ying; Zhou, Yu; Yang, Jie

    2016-01-01

    The GRAS gene family is one of the most important plant-specific gene families, which encodes transcriptional regulators and plays an essential role in plant development and physiological processes. The GRAS gene family has been well characterized in many higher plants such as Arabidopsis, rice, Chinese cabbage, tomato and tobacco. In this study, we identified 38 GRAS genes in sacred lotus (Nelumbo nucifera), analyzed their physical and chemical characteristics and performed phylogenetic analysis using the GRAS genes from eight representative plant species to show the evolution of GRAS genes in Planta. In addition, the gene structures and motifs of the sacred lotus GRAS proteins were characterized in detail. Comparative analysis identified 42 orthologous and 9 co-orthologous gene pairs between sacred lotus and Arabidopsis, and 35 orthologous and 22 co-orthologous gene pairs between sacred lotus and rice. Based on publically available RNA-seq data generated from leaf, petiole, rhizome and root, we found that most of the sacred lotus GRAS genes exhibited a tissue-specific expression pattern. Eight of the ten PAT1-clade GRAS genes, particularly NnuGRAS-05, NnuGRAS-10 and NnuGRAS-25, were preferentially expressed in rhizome and root. In summary, this is the first in silico analysis of the GRAS gene family in sacred lotus, which will provide valuable information for further molecular and biological analyses of this important gene family.

  17. Photoprotective Effect of Lotus (Nelumbo nucifera Gaertn.) Seed Tea against UVB Irradiation.

    PubMed

    Kim, Su-Yeon; Moon, Gap-Soon

    2015-09-01

    Lotus (Nelumbo nucifera Gaertn.) seed is widely used as a traditional medicine in countries of Asia. Among many functions of the lotus seed, one interesting activity is its skin protection from the sunlight and scar. In this study, we focused on the skin protective property of lotus seed tea against ultraviolet B (UVB) irradiation. Two groups of a hairless mouse model, water as control (water group) and lotus seed tea (LST group), were administrated a fluid drink water for six months. After 6 month of administration, UVB exposure was carried out to both groups for another 3 months. During and after the administration, the skin moisture content and the morphological and histopathological analyses through biopsy were carried out. Prior to UVB irradiation, no significant difference was discovered in the skin moisture content for the water group and LST group (P<0.05). However, drastic changes were observed after the UVB treatment. The LST group showed a clear evidence of skin protection compared to the control group (P<0.05). The moisture content, epidermal and horny layer thickness, and protein carbonyl values all revealed that the intake of the lotus seed tea enhanced protection against UVB exposure. As a result, the long-term intake of the lotus seed tea showed the effect of preventing loss of skin moisture, mitigating the formation of abnormal keratinocytes, and contributing to protein oxidation inhibition. PMID:26451352

  18. Reversible superhydrophilicity and superhydrophobicity on a lotus-leaf pattern.

    PubMed

    de Leon, Al; Advincula, Rigoberto C

    2014-12-24

    A facile approach of fabricating a temperature-responsive coating capable of switching reversibly from being superhydrophobic to superhydrophilic is presented. The approach combines micromolding, layer-by-layer assembly of the polymer macroinitiators, and surface-initiated polymerization. Changing between superhydrophobicity and superhydrophilicity depends heavily on the surface roughness and the switching of the surface energy levels. In this study, surface roughness was introduced by replicating the surface morphology of a lotus leaf. The switching of surface energy levels was made possible by grafting a temperature-responsive polymer brush. Wetting studies reveal that the reported approach not only replicates nature but also improves its property by making it responsive to stimulus. PMID:25412015

  19. Bioinspired Lotus-like Self-Illuminous Coating.

    PubMed

    Shi, Xiaodi; Dou, Renmei; Ma, Tianze; Liu, Weiyi; Lu, Xihua; Shea, Kenneth J; Song, Yanlin; Jiang, Lei

    2015-08-26

    The sensitivity of long persistent phosphor materials (LPP) to moisture greatly limits their applications especially in humid environments, which cause the hydrolysis of LPP and shorten their lifetime. In this work, a facile, environmentally friendly, and low-cost method was developed to prevent the infiltration of water or moisture to the LPP by doping LPP with SiO2 nanoparticles to form a superhydrophobic coating. The superhydrophobic coating provided a stable environment to the self-illuminous system, which not only can resist the infiltration of water but also can have good self-cleaning property, similar to the lotus leaf effect. This facile method will be very beneficial for expending further application of LPP especially in high humidity. PMID:26238797

  20. Multi-responsive hydrogel based on lotus root starch.

    PubMed

    Zhu, Baodong; Ma, Dongzhuo; Wang, Jian; Zhang, Jianwei; Zhang, Shuang

    2016-08-01

    The lotus root starch-based hydrogel was synthesized by free radical copolymerization. Fourier Transform Infrared Spectroscopy (FTIR) demonstrated that the formation of target product. X-ray diffraction (XRD) analysis showed the change of the starch's crystallization. The morphology and pore structure of the hydrogel were evaluated by Field Emission Scanning Electron Microscope (FESEM) and Biomicroscope. Thermogravimetric analysis revealed the better thermal stability of hydrogel. Furthermore, the swelling in CaCl2 and AlCl3 solutions/temperature (25°C-65°C) displayed the "overshooting effect" swelling-deswelling phenomenon with prolonging the swelling time. The hydrogel can rapidly response to various pH value as well. PMID:27177459

  1. Antipyretic and antinociceptive activity of Diospyros lotus L. in animals

    PubMed Central

    Rauf, Abdur; Uddin, Ghias; Siddiqui, Bina S.; Muhammad, Naveed; Khan, Haroon

    2014-01-01

    Objective To evaluate pharmacologically the traditional use of Diospyros lotus as antipyretic and antinociceptive in various animal models. Methods In vivo experimental models were used in this study. Antipyretic activity of extract/fractions was evaluated in brewer's yeast induced hyperthermic mice while antinociceptive activity was studied in acetic acid induced writhing test at 50 and 100 mg/kg i.p. Results The crude extract strongly ameliorated the induced pyrexia during various assessment times. Upon fractionation, the antipyretic effects were strongly augmented by the chloroform and ethyl acetate fractions of the plant. However, hexane and butanol fractions were insignificant in their effect as antipyretic. The extract showed marked inhibition on the noxious simulation induced by post acetic acid injection. The effect was strongly supported by other fraction expect hexane. Conclusions In short, our study scientifically validated the traditional use of the plant as antipyretic. PMID:25183115

  2. Pollination success of Lotus corniculatus (L.) in an urban context

    NASA Astrophysics Data System (ADS)

    Pellissier, Vincent; Muratet, Audrey; Verfaillie, Fabien; Machon, Nathalie

    2012-02-01

    Most anthropogenic activities are known to have deleterious effects on pollinator communities. However, little is known about the influence of urbanization on pollination ecosystem services. Here, we assessed the pollination service on Lotus corniculatus (L.), a self-sterile, strictly entogamous Fabaceae commonly observed in urban and suburban areas. We assessed the pollination success of artificial Lotus corniculatus populations at three levels: at large scale, along an urbanization gradient; at intermediate scale, based on landscape fragmentation within a 250 m radius and at local scale based on floral resource abundance and local habitat type. The main findings were that the pollination success, when assessed with the number of fruit produced per inflorescence, was lower in urban areas than in suburban ones, and was negatively affected by the number of impervious spaces in the neighborhood. The relationship between the number of fruits and the distance to the nearest impervious space was either positive or negative, depending on the gray/green ratio (low vs. high). Finally, on a local scale, floral resource abundance had a negative effect on pollination success when L. corniculatus populations were located in paved courtyards, and a positive one when they were located in parks. Pollination success seems to be explained by two intertwined gradients: landscape fragmentation estimated by the number of impervious spaces in a 250 m radius around L. corniculatus populations, and the behavior of bumblebees toward birdsfoot trefoil and floral displays, which appears to differ depending on whether a neighborhood is densely or sparsely urbanized. An abundance of attracting floral resources seems to enhance pollination success for L. corniculatus if it is not too isolated from other green spaces. These results have important implications for the sustainability of pollination success in towns by identifying local and landscape factors that influence reproductive success of

  3. Sulphasalazine and regression of rheumatoid nodules.

    PubMed

    Englert, H J; Hughes, G R; Walport, M J

    1987-03-01

    The regression of small rheumatoid nodules was noted in four patients after starting sulphasalazine therapy. This coincided with an improvement in synovitis and also falls in erythrocyte sedimentation rate (ESR) and C reactive protein (CRP). The relation between the nodule regression and the sulphasalazine therapy is discussed. PMID:2883940

  4. Evolution and taxonomy of native mesorhizobia nodulating medicinal Glycyrrhiza species in China.

    PubMed

    Mousavi, Seyed Abdollah; Li, Li; Wei, Gehong; Räsänen, Leena; Lindström, Kristina

    2016-06-01

    Previously, 159 bacterial strains were isolated from the root nodules of wild perennial Glycyrrhiza legume species grown on 40 sites in central and north-western China, in which 57 strains were classified as "true symbionts" belonging to the genus Mesorhizobium based on amplified fragment length polymorphism (AFLP) genomic fingerprinting and partial sequences of the 16S rRNA gene [20]. In the present work, the phylogeny of Glycyrrhiza nodulating mesorhizobia was further examined by multilocus sequence analysis (MLSA). The concatenated gene tree of three housekeeping genes (16S rRNA, recA, and rpoB) of 59 strains including the 29 mesorhizobial test strains and 30 type mesorhizobial species, was constructed applying the maximum likelihood method and Bayesian inference. In the concatenated gene tree, the 29 test strains were distributed in seven separate clades. Seventeen test strains clustered with Mesorhizobium tianshanense, Mesorhizobium temperatum, Mesorhizobium muleiense, and Mesorhizobium alhagi with high bootstrap support (BS>85%). Eight test strains did not cluster with any of the described Mesorhizobium species. Based on the results, we proposed these eight test strains might belong to a putative new species of the genus Mesorhizobium. The sequences of three accessory genes (nodA, nodC, and nifH) of the test strains were also analyzed and were compared with those of representatives of the 30 described mesorhizobial species. The results showed that mesorhizobia involved in symbiosis with Glycyrrhiza plants probably have acquired some genetic material from other rhizobia in co-evolution with Glycyrrhiza and other legume species. PMID:27105685

  5. [Root Nodule Bacteria Sinorhizobium meliloti: Tolerance to Salinity and Bacterial Genetic Determinants].

    PubMed

    Roumiantseva, M L; Muntyan, V S

    2015-01-01

    The theoretical and experimental data on salt tolerance of root nodule bacteria Sinorhizobium meliloti (Ensifer meliloti), an alfalfa symbiont, and on genetic determination of this feature are reviewed. Extensive data on the genes affecting adaptation of proteobacteria are provided, as well as on the groups of genes with activity depending on the osmolarity of the medium. Structural and functional polymorphism of the bet genes involved in betaine synthesis and transport in S. meliloti is discussed. The phenotypic and. genotypic polymorphism in 282 environmental rhizobial strains isolated from the centers of alfalfa diversity affected by aridity and salinity is discussed. The isolates from the Aral Sea area and northern Caucasus were shown to possess the betC gene represented by two types of alleles: the dominant A-type allele found in Rm 1021 and the less common divergent E-type allele, which was revealed in regions at the frequencies at the frequencies of 0.35 and 0.48, respectively. In the isolates with the salt-tolerant phenotype, which were isolated from root nodules and subsequently formed less effective symbioses with alfalfa, the frequency of E-type alleles was 2.5 times higher. Analysis of the nucleotide and amino acid sequences of the E-type allele of the betC gene revealed that establishment of this allele in the population was a result of positive selection. It is concluded that diversification of the functionally diverse bet genes occurring in S. meliloti affects the salt tolerance and symbiotic effectivity of rhizobia. PMID:26263687

  6. Simulating nodules in chest radiographs with real nodules from multi-slice CT images

    NASA Astrophysics Data System (ADS)

    Schilham, Arnold; van Ginneken, Bram

    2006-03-01

    To improve the detection of nodules in chest radiographs, large databases of chest radiographs with annotated, proven nodules are needed for training of both radiologists and computer-aided detection systems. The construction of such databases is a laborious and time-consuming task. This study presents a novel technique to produce large amounts of chest x-rays with annotated, simulated nodules. Realistic nodules in radiographs are generated using real nodules segmented from CT images. Results from an observer study indicate that the simulated nodules can not be distinguished from real nodules. This method has great potential to aid the development of automated detection systems and to generate teaching files for human observers.

  7. How membranes shape plant symbioses: signaling and transport in nodulation and arbuscular mycorrhiza

    PubMed Central

    Bapaume, Laure; Reinhardt, Didier

    2012-01-01

    As sessile organisms that cannot evade adverse environmental conditions, plants have evolved various adaptive strategies to cope with environmental stresses. One of the most successful adaptations is the formation of symbiotic associations with beneficial microbes. In these mutualistic interactions the partners exchange essential nutrients and improve their resistance to biotic and abiotic stresses. In arbuscular mycorrhiza (AM) and in root nodule symbiosis (RNS), AM fungi and rhizobia, respectively, penetrate roots and accommodate within the cells of the plant host. In these endosymbiotic associations, both partners keep their plasma membranes intact and use them to control the bidirectional exchange of signaling molecules and nutrients. Intracellular accommodation requires the exchange of symbiotic signals and the reprogramming of both interacting partners. This involves fundamental changes at the level of gene expression and of the cytoskeleton, as well as of organelles such as plastids, endoplasmic reticulum (ER), and the central vacuole. Symbiotic cells are highly compartmentalized and have a complex membrane system specialized for the diverse functions in molecular communication and nutrient exchange. Here, we discuss the roles of the different cellular membrane systems and their symbiosis-related proteins in AM and RNS, and we review recent progress in the analysis of membrane proteins involved in endosymbiosis. PMID:23060892

  8. [Bacteria closely related to Phyllobacterium trifolii according to their 16S rRNA gene are discovered in the nodules of Hungarian sainfoin].

    PubMed

    Baĭmiev, Al Kh; Baĭmiev, An Kh; Gubaĭdullin, I I; Kulikova, O L; Chemeris, A V

    2007-05-01

    The population genetic diversity and phylogeny of the bacteria entering the symbiosis with sainfoin that grows on the Chesnokovskaya Mountain, Ufa region, Republic of Bashkortostan, have been studied. RAPD analysis of DNA polymorphism of the microbial strains grown from the nodules of 20 plants using several random primers detected a high degree of genetic homogeneity in their population as compared with the populations of rhizobia of other leguminous plants growing at the same site. Sequencing of 16S rRNA genes of the three most different samples have demonstrated that these genes were identical and display 99.9% homology with the sequence of Phyllobacterium trifolii 16S rRNA gene. PMID:17633565

  9. Rheumatoid nodule presenting as Morton's neuroma.

    PubMed

    Chaganti, S; Joshy, S; Hariharan, K; Rashid, M

    2013-09-01

    Among 101 feet that presented with symptoms and signs similar to Morton's neuroma, intermetatarsal rheumatoid nodules were found in five feet (three patients). Two patients had bilateral involvement. Histology of the excised tissue showed the presence of a rheumatoid nodule and Morton's neuroma in four feet and a rheumatoid nodule with unremarkable nerve bundles in one. A rheumatoid nodule can coexist with Morton's neuroma, as seen in our patients, and the presentation is often similar to that of a Morton's neuroma. Our patients were rendered asymptomatic with surgical treatment and went on to have appropriate management of rheumatoid arthritis. Rheumatoid nodule should be considered in the differential diagnosis of Morton's neuroma in not only rheumatoid arthritis patients but also asymptomatic patients who have never been tested for rheumatoid antibodies. PMID:23135058

  10. [Thyroid nodules – how to proceed?].

    PubMed

    Murer, Karin; Müller, Werner

    2016-01-01

    Asymptomatic thyroid nodules are very common and detected with increasing frequency by radiological investigations of the neck as so-called “incidentalomas”. If a thyroid nodule is found, the question arises how to proceed with this case. The goal is to recognize the very rare malignant nodules and to perform an adequate therapy. Every work-up of a thyroid nodule includes functional evaluation by determination of thyroid stimulating hormone (TSH). Is the level of the hormone suppressed, a scintigraphy is indicated to rule out a hot thyroid nodule implying a benign finding. Ultrasound is the imaging of choice for the thyroid gland and provides information with respect to size, number and configuration of the nodes. Depending on sonographic evaluation and other possible risk factors, a fine-needle aspiration biopsy of the node is performed. Based on the cytologic findings further therapeutic procedures are determined. PMID:27132640

  11. Physiological Changes in Rhizobia after Growth in Peat Extract May Be Related to Improved Desiccation Tolerance

    PubMed Central

    Wilkes, Meredith A.; Deaker, Rosalind

    2013-01-01

    Improved survival of peat-cultured rhizobia compared to survival of liquid-cultured cells has been attributed to cellular adaptations during solid-state fermentation in moist peat. We have observed improved desiccation tolerance of Rhizobium leguminosarum bv. trifolii TA1 and Bradyrhizobium japonicum CB1809 after aerobic growth in water extracts of peat. Survival of TA1 grown in crude peat extract was 18-fold greater than that of cells grown in a defined liquid medium but was diminished when cells were grown in different-sized colloidal fractions of peat extract. Survival of CB1809 was generally better when grown in crude peat extract than in the control but was not statistically significant (P > 0.05) and was strongly dependent on peat extract concentration. Accumulation of intracellular trehalose by both TA1 and CB1809 was higher after growth in peat extract than in the defined medium control. Cells grown in water extracts of peat exhibit morphological changes similar to those observed after growth in moist peat. Electron microscopy revealed thickened plasma membranes, with an electron-dense material occupying the periplasmic space in both TA1 and CB1809. Growth in peat extract also resulted in changes to polypeptide expression in both strains, and peptide analysis by liquid chromatography-mass spectrometry indicated increased expression of stress response proteins. Our results suggest that increased capacity for desiccation tolerance in rhizobia is multifactorial, involving the accumulation of trehalose together with increased expression of proteins involved in protection of the cell envelope, repair of DNA damage, oxidative stress responses, and maintenance of stability and integrity of proteins. PMID:23603686

  12. Changes in extreme high-temperature tolerance and activities of antioxidant enzymes of sacred lotus seeds.

    PubMed

    Ding, YanFen; Cheng, HongYan; Song, SongQuan

    2008-09-01

    Sacred lotus (Nelumbo nucifera Gaertn. 'Tielian') seed is long-lived and extremely tolerant of high temperature. Water content of lotus and maize seeds was 0.103 and 0.129 g H2O [g DW](-1), respectively. Water content, germination percentage and fresh weight of seedlings produced by surviving seeds gradually decreased with increasing treatment time at 100 degrees C. Germination percentage of maize (Zea mays L. 'Huangbaogu') seeds was zero after they were treated at 100 degrees C for 15 min and that of lotus seeds was 13.5% following the treatment at 100 degrees C for 24 h. The time in which 50% of lotus and maize seeds were killed by 100 degrees C was about 14.5 h and 6 min, respectively. With increasing treatment time at 100 degrees C, relative electrolyte leakage of lotus axes increased significantly, and total chlorophyll content of lotus axes markedly decreased. When treatment time at 100 degrees C was less than 12 h, subcellular structure of lotus hypocotyls remained fully intact. When treatment time at 100 degrees C was more than 12 h, plasmolysis gradually occurred, endoplasmic reticulum became unclear, nuclei and nucleoli broke down, most of mitochondria swelled, lipid granules accumulated at the cell periphery, and organelles and plasmolemma collapsed. Malondialdehyde (MDA) content of lotus axes and cotyledons decreased during 0 -12 h of the treatment at 100 degrees C and then increased. By contrast, the MDA content of maize embryos and endosperms increased during 5-10 min of the treatment at 100 degrees C and then decreased slightly. For lotus seeds: (1) activities of superoxide dismutase (SOD) and glutathione reductase (GR) of axes and cotyledons and of catalase (CAT) of axes increased during the early phase of treatment at 100 degrees C and then decreased; and (2) activities of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) of axes and cotyledons and of CAT of cotyledons gradually decreased with increasing treatment time at 100 degrees

  13. SCARN a Novel Class of SCAR Protein That Is Required for Root-Hair Infection during Legume Nodulation.

    PubMed

    Qiu, Liping; Lin, Jie-Shun; Xu, Ji; Sato, Shusei; Parniske, Martin; Wang, Trevor L; Downie, J Allan; Xie, Fang

    2015-10-01

    Rhizobial infection of legume root hairs requires a rearrangement of the actin cytoskeleton to enable the establishment of plant-made infection structures called infection threads. In the SCAR/WAVE (Suppressor of cAMP receptor defect/WASP family verpolin homologous protein) actin regulatory complex, the conserved N-terminal domains of SCAR proteins interact with other components of the SCAR/WAVE complex. The conserved C-terminal domains of SCAR proteins bind to and activate the actin-related protein 2/3 (ARP2/3) complex, which can bind to actin filaments catalyzing new actin filament formation by nucleating actin branching. We have identified, SCARN (SCAR-Nodulation), a gene required for root hair infection of Lotus japonicus by Mesorhizobium loti. Although the SCARN protein is related to Arabidopsis thaliana SCAR2 and SCAR4, it belongs to a distinct legume-sub clade. We identified other SCARN-like proteins in legumes and phylogeny analyses suggested that SCARN may have arisen from a gene duplication and acquired specialized functions in root nodule symbiosis. Mutation of SCARN reduced formation of infection-threads and their extension into the root cortex and slightly reduced root-hair length. Surprisingly two of the scarn mutants showed constitutive branching of root hairs in uninoculated plants. However we observed no effect of scarn mutations on trichome development or on the early actin cytoskeletal accumulation that is normally seen in root hair tips shortly after M. loti inoculation, distinguishing them from other symbiosis mutations affecting actin nucleation. The C-terminal domain of SCARN binds to ARPC3 and ectopic expression of the N-terminal SCAR-homology domain (but not the full length protein) inhibited nodulation. In addition, we found that SCARN expression is enhanced by M. loti in epidermal cells and that this is directly regulated by the NODULE INCEPTION (NIN) transcription factor. PMID:26517270

  14. SCARN a Novel Class of SCAR Protein That Is Required for Root-Hair Infection during Legume Nodulation

    PubMed Central

    Qiu, Liping; Lin, Jie-shun; Xu, Ji; Sato, Shusei; Parniske, Martin; Wang, Trevor L.; Downie, J. Allan; Xie, Fang

    2015-01-01

    Rhizobial infection of legume root hairs requires a rearrangement of the actin cytoskeleton to enable the establishment of plant-made infection structures called infection threads. In the SCAR/WAVE (Suppressor of cAMP receptor defect/WASP family verpolin homologous protein) actin regulatory complex, the conserved N-terminal domains of SCAR proteins interact with other components of the SCAR/WAVE complex. The conserved C-terminal domains of SCAR proteins bind to and activate the actin-related protein 2/3 (ARP2/3) complex, which can bind to actin filaments catalyzing new actin filament formation by nucleating actin branching. We have identified, SCARN (SCAR-Nodulation), a gene required for root hair infection of Lotus japonicus by Mesorhizobium loti. Although the SCARN protein is related to Arabidopsis thaliana SCAR2 and SCAR4, it belongs to a distinct legume-sub clade. We identified other SCARN-like proteins in legumes and phylogeny analyses suggested that SCARN may have arisen from a gene duplication and acquired specialized functions in root nodule symbiosis. Mutation of SCARN reduced formation of infection-threads and their extension into the root cortex and slightly reduced root-hair length. Surprisingly two of the scarn mutants showed constitutive branching of root hairs in uninoculated plants. However we observed no effect of scarn mutations on trichome development or on the early actin cytoskeletal accumulation that is normally seen in root hair tips shortly after M. loti inoculation, distinguishing them from other symbiosis mutations affecting actin nucleation. The C-terminal domain of SCARN binds to ARPC3 and ectopic expression of the N-terminal SCAR-homology domain (but not the full length protein) inhibited nodulation. In addition, we found that SCARN expression is enhanced by M. loti in epidermal cells and that this is directly regulated by the NODULE INCEPTION (NIN) transcription factor. PMID:26517270

  15. Cytopathology of Follicular Cell Nodules.

    PubMed

    Damiani, Domenico; Suciu, Voichita; Vielh, Philippe

    2015-12-01

    This article corresponds to a lecture delivered during the Endocrine Pathology Society symposium held in Boston on 21 March 2015 (104th USCAP meeting, March 21-27). It focuses on the importance of cytopathology in endocrine thyroid pathology and the limits and pitfalls of diagnosis in follicular cell lesions. Lights and shadows are present in each diagnostic technique: Fine needle aspiration has imposed itself as a gold standard in thyroid nodules thanks to its easiness of execution and high cost-effectiveness ratio. A milestone in this field is represented by the National Cancer Institute (NCI) Thyroid Fine Needle Aspiration (FNA) State of the State of the Science Conference hosted in October 22-23, 2007 by the NCI, followed by a series of documents published in Diagnostic Cytopathology and Cytojournal (2008) as well as in an atlas entitled: The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC): terminology and criteria (2010, Springer). "Gray" zones still remain, causing difficulties and anxiety to the cytopathologist when facing challenging cases. Each diagnostic category of TBSRTC is analyzed and discussed in a concise fashion with special emphasis on challenging cases such as atypia of undetermined significance (AUS), suspicion for follicular neoplasms (SFNs), diagnoses of papillary thyroid carcinoma (PTC) in Hashimoto thyroiditis and follicular variant of papillary carcinoma (FVPTC). Our aim was to better define and clarify the spectrum of follicular cell lesions in thyroid nodule samplings and to underline the diagnostic limits in order to avoid pitfalls. New emerging molecular biology techniques may represent useful tools in selected morphological challenging cases and lead to new therapeutic approaches in line with drug-tailored therapy and personalized medicine. PMID:26227345

  16. Influence of Nodule Detection Software on Radiologists’ Confidence in Identifying Pulmonary Nodules With Computed Tomography

    PubMed Central

    Nietert, Paul J.; Ravenel, James G.; Taylor, Katherine K.; Silvestri, Gerard A.

    2011-01-01

    Purpose With advances in technology, detection of small pulmonary nodules is increasing. Nodule detection software (NDS) has been developed to assist radiologists with pulmonary nodule diagnosis. Although it may increase sensitivity for small nodules, often there is an accompanying increase in false-positive findings. We designed a study to examine the extent to which computed tomography (CT) NDS influences the confidence of radiologists in identifying small pulmonary nodules. Materials and Methods Eight radiologists (readers) with different levels of experience examined thoracic CT scans of 131 cases and identified all the clinically relevant pulmonary nodules. The reference standard was established by an expert, dedicated thoracic radiologist. For each nodule, the readers recorded nodule size, density, location, and confidence level. Two weeks (or more) later, the readers reinterpreted the same scans; however, this time they were provided marks, when present, as indicated by NDS and asked to reassess their level of confidence. The effect of NDS on changes in reader confidence was assessed using multivariable generalized linear regression models. Results A total of 327 unique nodules were identified. Declines in confidence were significantly (P<0.05) associated with the absence of an NDS mark and smaller nodules (odds ratio=71.0, 95% confidence interval =14.8–339.7). Among nodules with pre-NDS confidence less than 100%, increases in confidence were significantly (P<0.05) associated with the presence of an NDS mark (odds ratio=6.0, 95% confidence interval =2.7–13.6) and larger nodules. Secondary findings showed that NDS did not improve reader diagnostic accuracy. Conclusion Although in this study NDS does not seem to enhance reader accuracy, the confidence of the radiologists in identifying small pulmonary nodules with CT is greatly influenced by NDS. PMID:20498624

  17. Aspartate Aminotransferase in Alfalfa Root Nodules 1

    PubMed Central

    Farnham, Mark W.; Griffith, Stephen M.; Miller, Susan S.; Vance, Carroll P.

    1990-01-01

    Aspartate aminotransferase (AAT) plays an important role in nitrogen metabolism in all plants and is particularly important in the assimilation of fixed N derived from the legume-Rhizoblum symbiosis. Two isozymes of AAT (AAT-1 and AAT-2) occur in alfalfa (Medicago sativa L.). Antibodies against alfalfa nodule AAT-2 do not recognize AAT-1, and these antibodies were used to study AAT-2 expression in different tissues and genotypes of alfalfa and also in other legume and nonlegume species. Rocket immunoelectrophoresis indicated that nodules of 38-day-old alfalfa plants contained about eight times more AAT-2 than did nodules of 7-day-old plants, confirming the nodule-enhanced nature of this isozyme. AAT-2 was estimated to make up 16, 15, 5, and 8 milligrams per gram of total soluble protein in mature nodules, roots, stems, and leaves, respectively, of effective N2-fixing alfalfa. The concentration of AAT-2 in nodules of ineffective non-N2-fixing alafalfa genotypes was about 70% less than that of effective nodules. Western blots of soluble protein from nodules of nine legume species indicated that a 40-kilodalton polypeptide that reacts strongly with AAT-2 antibodies is conserved in legumes. Nodule AAT-2 immunoprecipitation data suggested that amide- and ureide-type legumes may differ in expression and regulation of the enzyme. In addition, Western blotting and immunoprecipitations of AAT activity demonstrated that antibodies against alfalfa AAT-2 are highly cross-reactive with AAT enzyme protein in leaves of soybean (Glycine max L.), wheat (Triticum aestivum L.), and maize (Zea mays L.) and in roots of maize, but not with AAT in soybean and wheat roots. Results from this study indicate that AAT-2 is structurally conserved and localized in similar tissues among diverse species. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:16667896

  18. Oxidation state of marine manganese nodules

    USGS Publications Warehouse

    Piper, D.Z.; Basler, J.R.; Bischoff, J.L.

    1984-01-01

    Analyses of the bulk oxidation state of marine manganese nodules indicates that more than 98% of the Mn in deep ocean nodules is present as Mn(IV). The samples were collected from three quite different areas: the hemipelagic environment of the Guatemala Basin, the pelagic area of the North Pacific, and seamounts in the central Pacific. Results of the study suggest that todorokite in marine nodules is fully oxidized and has the following stoichiometry: (K, Na, Ca, Ba).33(Mg, Cu, Ni).76Mn5O22(H2O)3.2. ?? 1984.

  19. Lotus (Nelumbo nuficera) flower essential oil increased melanogenesis in normal human melanocytes

    PubMed Central

    Jeon, Songhee; Kim, Nan-Hyung; Koo, Byung-Soo; Kim, Ji-Young

    2009-01-01

    In this study, the essential oil from lotus flower extract, including petals and stamens, was assessed with regard to its effects on melanogenesis in human melanocytes. The lotus flower essential oil was shown to stimulate melanin synthesis and tyrosinase activity in a dose-dependent manner. The lotus flower essential oil induced the expression of tyrosinase, microphthalmia-associated transcription factor M (MITF-M), and tyrosinase-related proten-2 (TRP-2) proteins, but not tyrosinase mRNA. Moreover, it increased the phosphorylation of ERK and cAMP response element binding protein (CREB). In order to verify the effective components of the lotus flower oil, its lipid composition was assessed. It was found to be comprised of palmitic acid methyl ester (22.66%), linoleic acid methyl ester (11.16%), palmitoleic acid methyl ester (7.55%) and linolenic acid methyl ester (5.16%). Among these components, palmitic acid methyl ester clearly induced melanogenesis as the result of increased tyrosinase expression, thereby indicating that it may play a role in the regulation of melanin content. Thus, our results indicate that lotus flower oil may prove useful in the development of gray hair prevention agents or tanning reagents. PMID:19322028

  20. Proteomic and Epigenetic Analyses of Lotus (Nelumbo nucifera) Petals Between Red and White cultivars.

    PubMed

    Deng, Jiao; Fu, Ziyang; Chen, Sha; Damaris, Rebecca Njeri; Wang, Kun; Li, Tingting; Yang, Pingfang

    2015-08-01

    Lotus is a vital aquatic ornamental plant with different flower colors. To explore the flower coloration mechanism in lotus, the constituents and contents of pigments in two lotus cultivars with red and white flowers were analyzed. Although flavones and flavonols were detected in both cultivars, anthocyanins could only be detected in the red cultivar. A comparative proteomics analysis on the flower petals between these two cultivars was conducted. A total of 88 differentially expressed proteins were identified with 36 more abundant and 52 less abundant in the red than in the white cultivar. Among them, four enzymes involved in the anthocyanin pathway were identified, i.e. flavanone 3-hydroxylase, anthocyanidin synthase, anthocyanidin 3-O-glucosyltransferase and glutathione S-transferase. Analysis of the expression patterns of anthocyanin biosynthetic genes indicated that the anthocyanindin synthase (ANS) gene might be the critical gene determining anthocyanin biosynthesis and accumulation in lotus flower. Further analysis showed that different methylation intensities on the promoter sequence of the ANS gene might result in the different flower coloration in the red and white cultivar. This study provides new insights into the mechanism of flower coloration in lotus, and may be helpful in its breeding and germplasm enhancement. PMID:26019267

  1. Friend or Foe—Light Availability Determines the Relationship between Mycorrhizal Fungi, Rhizobia and Lima Bean (Phaseolus lunatus L.)

    PubMed Central

    Ballhorn, Daniel J.; Schädler, Martin; Elias, Jacob D.; Millar, Jess A.; Kautz, Stefanie

    2016-01-01

    Plant associations with root microbes represent some of the most important symbioses on earth. While often critically promoting plant fitness, nitrogen-fixing rhizobia and arbuscular mycorrhizal fungi (AMF) also demand significant carbohydrate allocation in exchange for key nutrients. Though plants may often compensate for carbon loss, constraints may arise under light limitation when plants cannot extensively increase photosynthesis. Under such conditions, costs for maintaining symbioses may outweigh benefits, turning mutualist microbes into parasites, resulting in reduced plant growth and reproduction. In natural systems plants commonly grow with different symbionts simultaneously which again may interact with each other. This might add complexity to the responses of such multipartite relationships. We experimented with lima bean (Phaseolus lunatus), which efficiently forms associations with both types of root symbionts. We applied full light and low-light to each of four treatments of microbial inoculation. After an incubation period of 14 weeks, we quantified vegetative aboveground and belowground biomass and number and viability of seeds to determine effects of combined inoculant and light treatment on plant fitness. Under light-limited conditions, vegetative and reproductive traits were inhibited in AMF and rhizobia inoculated lima bean plants relative to controls (un-colonized plants). Strikingly, reductions in seed production were most critical in combined treatments with rhizobia x AMF. Our findings suggest microbial root symbionts create additive costs resulting in decreased plant fitness under light-limited conditions. PMID:27136455

  2. Friend or Foe-Light Availability Determines the Relationship between Mycorrhizal Fungi, Rhizobia and Lima Bean (Phaseolus lunatus L.).

    PubMed

    Ballhorn, Daniel J; Schädler, Martin; Elias, Jacob D; Millar, Jess A; Kautz, Stefanie

    2016-01-01

    Plant associations with root microbes represent some of the most important symbioses on earth. While often critically promoting plant fitness, nitrogen-fixing rhizobia and arbuscular mycorrhizal fungi (AMF) also demand significant carbohydrate allocation in exchange for key nutrients. Though plants may often compensate for carbon loss, constraints may arise under light limitation when plants cannot extensively increase photosynthesis. Under such conditions, costs for maintaining symbioses may outweigh benefits, turning mutualist microbes into parasites, resulting in reduced plant growth and reproduction. In natural systems plants commonly grow with different symbionts simultaneously which again may interact with each other. This might add complexity to the responses of such multipartite relationships. We experimented with lima bean (Phaseolus lunatus), which efficiently forms associations with both types of root symbionts. We applied full light and low-light to each of four treatments of microbial inoculation. After an incubation period of 14 weeks, we quantified vegetative aboveground and belowground biomass and number and viability of seeds to determine effects of combined inoculant and light treatment on plant fitness. Under light-limited conditions, vegetative and reproductive traits were inhibited in AMF and rhizobia inoculated lima bean plants relative to controls (un-colonized plants). Strikingly, reductions in seed production were most critical in combined treatments with rhizobia x AMF. Our findings suggest microbial root symbionts create additive costs resulting in decreased plant fitness under light-limited conditions. PMID:27136455

  3. [Benign thyroid nodules: diagnostic and therapeutic approach].

    PubMed

    Durante, Cosimo; Cava, Francesco; Paciaroni, Alessandra; Filetti, Sebastiano

    2008-05-01

    In the last years an increase in thyroid nodules detection has been reported from several epidemiological studies. This trend is largely due to the routine use of diagnostic sonography procedures in clinical practice. Thyroid nodules, both palpable or not palpable, rarely turn out to be malignant. Fine-needle aspiration cytology (FNAc) plays a central role in establishing the nature of the nodule. Excluded the presence of malignant lesions, which are generally treated with surgery, physicians are faced with a variety of therapeutic options, and choosing the optimal approach can be a difficult task. These include a periodic follow-up alone without treatment, the iodine supplementation, the thyroid-hormone suppressive therapy, the radioiodine administration, the percutaneous ethanol injections, and the new technique of laser photocoagulation. In all cases, decisions on the management of benign thyroid nodules should always be based on clinical target and a careful analysis of benefits and risks to the patient. PMID:18581970

  4. Structure characterization of protein fractions from lotus ( Nelumbo nucifera) seed

    NASA Astrophysics Data System (ADS)

    Zeng, Hong-Yan; Cai, Lian-Hui; Cai, Xi-Ling; Wang, Ya-Ju; Li, Yu-Qin

    2011-08-01

    Protein fractionation of lotus seed was carried out and the structures of the protein fractions were studied. Fourier transform infrared spectroscopy (FTIR) as well as ultraviolet visible spectroscopy (UV-vis) was used to investigate changes in molecular structures of the protein fractions. FTIR and UV-vis spectra showed the protein fractions had different protein molecular structures. FTIR spectra showed β-sheets and β-turns as the major secondary structures in the individual protein fractions, while the amounts of α-helix and random coil structures among the different fractions did not significantly change. The amounts of β-sheet structures of albumin and globulin were significantly higher than ones of prolamin and glutelin, implying albumin and globulin had high stabilities because of the high content in β-sheet structures. The observed similarity in the amounts of α-helix, random coil, β-sheet and β-turn structures shared by albumin and globulin indicated that their interior conformations were similar.

  5. Physiological temperature regulation by flowers of the sacred lotus

    PubMed Central

    Seymour, R. S.

    1998-01-01

    Flowers of the sacred lotus, Nelumbo nucifera Gaertn. (Nelumbonaceae) are thermogenic and physiologically thermoregulatory. The 42 g flowers remain between 30-36°C during a 2 to 4-day period despite fluctuations in environmental temperatures between about 10-45°C. As the ambient temperature drops, the flowers increase heat production in proportion. Temperature regulation apparently occurs at a cellular level, by a steep, reversible thermal inhibition of respiration at flower temperatures above 30°C. There was a marked time lag between change in flower temperature and compensatory response, suggesting regulation through a biochemical feedback mechanism rather than structural changes in enzymes or membranes. By oxidizing carbohydrate, the flowers produce up to 1 W, with about half of the heat coming from the 8.5 g carpellary receptacle. The period of temperature regulation begins before petal opening and continues through the period of stigma receptivity. Temperature regulation may reward insect pollinators with a warm, equable environment, or it possibly enhances and coordinates flower development.

  6. [Second structure of the protein factions from lotus seeds].

    PubMed

    Cai, Lian-Hui; Zeng, Hong-Yan; Cai, Xi-Ling; Wang, Ya-Ju

    2011-09-01

    Following the sequential Osborne extraction procedure, the proteins of lotus seeds were classified. The secondary structures of albumin, globulin, prolamine and glutelin fractions were determined by Fourier transform infrared spectroscopy (FTIR). The FTIR images of amide I and III bands from the four protein fractions were analyzed using Fourier deconvolution and curve-fitting technique. The results showed that there were minor differences in every corresponding peak position and peak area percent of secondary structure between albumin and globulin as well as between prolamin and glutelin. But there were differences in every corresponding peak position between albumin (or globulin) and prolamin (or glutelin). Especially the area percents of the corresponding nonrandom structures (alpha-helix and beta-sheet) of albumin and globulin were significantly larger than those of prolamin and glutelin. The contents of nonrandom structures of albumin and globulin extracted with 0.1 mol x L(-1) NaCl solution were about 55% and those of prolamine and glutelin fractions were only at round 40%, indicating that the secondary structures of the salt-extraction protein were ordered and stable. PMID:22097834

  7. Analysis of LBM (lithium blanket module) experiments at LOTUS

    SciTech Connect

    Stepanek, J.; Davidson, J.W.; Dudziak, D.J.; Haldy, P.A.; Pelloni, S.

    1986-01-01

    A Lithium Blanket Module (LBM) has been designed at General Atomic Company for testing on the Tokamak Fusion Test Reactor (TFTR). The LBM has both realistic fusion blanket materials and configuration and has been designed for detailed experimental analyses of tritium breeding and neutron flux spatial/spectral distributions. It is {approximately}80 cm{sup 3} and the breeding material is Li{sub 2}O. The main objective of the LBM program was to perform a series of experiments by irradiating it using the toroidal neutron source of the TFTR. The comparison between measured and calculated neutron spectra and reaction rates would indicate the accuracy of presently available nuclear data and calculational methods and show the need for future data evaluation and methods development. With a delay in undertaking the deuterium-tritium operation of the Princeton TFTR, it was clear that the LOTUS facility could now provide an extremely valuable resolution of basic technological uncertainties in fusion reactor blanket physics. This resolution has been a major force behind EPRI's fusion program. 6 refs.

  8. Co-Inoculation with Rhizobia and AMF Inhibited Soybean Red Crown Rot: From Field Study to Plant Defense-Related Gene Expression Analysis

    PubMed Central

    Gao, Xiang; Lu, Xing; Wu, Man; Zhang, Haiyan; Pan, Ruqian; Tian, Jiang; Li, Shuxian; Liao, Hong

    2012-01-01

    Background Soybean red crown rot is a major soil-borne disease all over the world, which severely affects soybean production. Efficient and sustainable methods are strongly desired to control the soil-borne diseases. Principal Findings We firstly investigated the disease incidence and index of soybean red crown rot under different phosphorus (P) additions in field and found that the natural inoculation of rhizobia and arbuscular mycorrhizal fungi (AMF) could affect soybean red crown rot, particularly without P addition. Further studies in sand culture experiments showed that inoculation with rhizobia or AMF significantly decreased severity and incidence of soybean red crown rot, especially for co-inoculation with rhizobia and AMF at low P. The root colony forming unit (CFU) decreased over 50% when inoculated by rhizobia and/or AMF at low P. However, P addition only enhanced CFU when inoculated with AMF. Furthermore, root exudates of soybean inoculated with rhizobia and/or AMF significantly inhibited pathogen growth and reproduction. Quantitative RT-PCR results indicated that the transcripts of the most tested pathogen defense-related (PR) genes in roots were significantly increased by rhizobium and/or AMF inoculation. Among them, PR2, PR3, PR4 and PR10 reached the highest level with co-inoculation of rhizobium and AMF. Conclusions Our results indicated that inoculation with rhizobia and AMF could directly inhibit pathogen growth and reproduction, and activate the plant overall defense system through increasing PR gene expressions. Combined with optimal P fertilization, inoculation with rhizobia and AMF could be considered as an efficient method to control soybean red crown rot in acid soils. PMID:22442737

  9. Incidentally diagnosed pulmonary nodule: a diagnostic algorithm

    PubMed Central

    Rzyman, Witold

    2014-01-01

    Asymptomatic solitary pulmonary nodules incidentally revealed by computed tomography has become a serious medical problem. Depending on their diameter, solid, part-solid, or pure ground-glass pulmonary nodules may be observed, diagnosed radiologically/invasively, or resected in accordance with international guidelines. Pure ground-glass nodules, semi-solid lesions, or solid lesions smaller than 8 mm should be monitored by serial low-dose computed tomography. In the case of solid nodules greater than 8 mm, the assessment of the risk of malignancy is recommended. Patients at high risk of lung cancer with pulmonary lesions should undergo diagnostic investigation, or the nodule should be resected. If the risk of lung cancer is low, the patients may be monitored. Needle aspiration biopsy is the most important invasive method of tumor diagnosis. Cytological or histopathological diagnosis is helpful in appropriate clinical decision making that reduces the risk of unnecessary surgery, decreasing the rate of benign nodule resections and thus reducing the costs of medical treatment. PMID:26336456

  10. Mesorhizobium waimense sp. nov. isolated from Sophora longicarinata root nodules and Mesorhizobium cantuariense sp. nov. isolated from Sophora microphylla root nodules.

    PubMed

    De Meyer, Sofie E; Tan, Heng Wee; Heenan, Peter B; Andrews, Mitchell; Willems, Anne

    2015-10-01

    In total 14 strains of Gram-stain-negative, rod-shaped bacteria were isolated from Sophora longicarinata and Sophora microphylla root nodules and authenticated as rhizobia on these hosts. Based on the 16S rRNA gene phylogeny, they were shown to belong to the genus Mesorhizobium, and the strains from S. longicarinata were most closely related to Mesorhizobium amorphae ACCC 19665T (99.8–99.9 %), Mesorhizobium huakuii IAM 14158T (99.8–99.9 %), Mesorhizobium loti USDA 3471T (99.5–99.9 %) and Mesorhizobium septentrionale SDW 014T (99.6–99.8 %), whilst the strains from S. microphylla were most closely related to Mesorhizobium ciceri UPM-Ca7T (99.8–99.9 %), Mesorhizobium qingshengii CCBAU 33460T (99.7 %) and Mesorhizobium shangrilense CCBAU 65327T (99.6 %). Additionally, these strains formed two distinct groups in phylogenetic trees of the housekeeping genes glnII, recA and rpoB. Chemotaxonomic data, including fatty acid profiles, supported the assignment of the strains to the genus Mesorhizobium and allowed differentiation from the closest neighbours. Results of DNA–DNA hybridizations, MALDI-TOF MS analysis, ERIC-PCR, and physiological and biochemical tests allowed genotypic and phenotypic differentiation of our strains from their closest neighbouring species. Therefore, the strains isolated from S. longicarinata and S. microphylla represent two novel species for which the names Mesorhizobium waimense sp. nov. (ICMP 19557T = LMG 28228T = HAMBI 3608T) and Mesorhizobium cantuariense sp. nov. (ICMP 19515T = LMG 28225T = HAMBI 3604T), are proposed respectively. PMID:26296780

  11. Effect of cooking on physicochemical properties and volatile compounds in lotus root (Nelumbo nucifera Gaertn).

    PubMed

    Li, Shuyi; Li, Xiaojin; Lamikanra, Olusola; Luo, Qing; Liu, Zhiwei; Yang, Jun

    2017-02-01

    The effects of boiling and steaming on lotus root volatile compounds and some of its physicochemical properties were determined. A total of 52 compounds identified in the raw tuber by GC-MS were a combination of the rhizome's native compounds and those from the soil and water environment, and are predominantly a mixture of straight chain and cyclic alkanes, and aromatic hydrocarbons. Boiling increased concentrations of most of these compounds, unlike steaming that lowered total volatile components of the tuber. Cooking increased complexity of volatile compounds with the production of new compounds such as methylated derivatives, particularly in steam cooked lotus. Other heat-induced compounds include antioxidants such as butylated hydroxyl compounds and antifungal organic compounds such as dimethyl disulfide. Instrumental texture measurements indicate that the characteristic post-cooked retention of crunchiness in lotus root is likely to be related to retention of its springiness index through the cooking process. PMID:27596426

  12. Fabrication of Lotus-Type Porous Aluminum through Thermal Decomposition Method

    NASA Astrophysics Data System (ADS)

    Kim, S. Y.; Park, J. S.; Nakajima, H.

    2009-04-01

    Lotus-type porous aluminum with cylindrical pores was fabricated by unidirectional solidification through thermal decomposition of calcium hydroxide, sodium bicarbonate, or titanium hydride. The pore-forming gas decomposed from calcium hydroxide, sodium bicarbonate, and titanium hydride is identified as hydrogen. The elongated pores are evolved due to the solubility gap between liquid and solid when the melt dissolving hydrogen is solidified unidirectionally. The porosity of lotus aluminum is as high as 20 pct despite the type of the compounds. The pore size decreases and the pore density increases with increasing amount of calcium hydroxide, which is explained by an increase in the number of pore nucleation sites. The porosity and pore size in lotus aluminum fabricated using calcium hydroxide decrease with increasing argon pressure, which is explained by Boyle’s law. It is suggested that this fabrication method is simple and safe, which makes it superior to the conventional technique using high-pressure hydrogen gas.

  13. Crotalarieae and Genisteae of the South African Great Escarpment are nodulated by novel Bradyrhizobium species with unique and diverse symbiotic loci.

    PubMed

    Beukes, Chrizelle W; Stępkowski, Tomasz; Venter, Stephanus N; Cłapa, Tomasz; Phalane, Francina L; le Roux, Marianne M; Steenkamp, Emma T

    2016-07-01

    The genus Bradyrhizobium contains predominantly nitrogen-fixing legume symbionts. Phylogenetic analysis of the genes responsible for their symbiotic abilities (i.e., those encoded on the nodulation [nod] and nitrogen-fixation [nif] loci) has facilitated the development of an extensive phylogeographic framework for the genus. This framework however contains only a few nodulating isolates from Africa. Here we focused on nodulating Bradyrhizobium isolates associated with native southern African legumes in the tribes Genisteae and Crotalarieae found along the Great Escarpment in the Mpumalanga Province of South Africa. The aims of this study were to: (1) obtain rhizobial isolates from legumes in the Genisteae and Crotalarieae; (2) verify their nodulation ability; (3) characterize them to species level based on phylogenetic analyses of several protein coding gene regions (atpD, dnaK, glnII, recA, rpoB and gyrB) and (4) determine their placement in the phylogeographic framework inferred from the sequences of the symbiotic loci nodA and nifD. Twenty of the 21 Bradyrhizobium isolates belonged to six novel species, while one was conspecific with the recently described B. arachidis. Among these isolates, the nodA phylogeny revealed several new clades, with 18 of our isolates found in Clades XIV and XV, and only three forming part of the cosmopolitan Clade III. These strains formed predominantly the same groups in the nifD phylogeny although with slight differences; indicating that both vertical and horizontal inheritance of the symbiotic loci occurred. These findings suggest that the largely unexplored diversity of indigenous African rhizobia are characterized by unique ancestries that might mirror the distribution of their hosts and the environmental factors driving their evolution. PMID:27068839

  14. Heat Transfer Capacity of Lotus-Type Porous Copper Heat Sink

    NASA Astrophysics Data System (ADS)

    Chiba, Hiroshi; Ogushi, Tetsuro; Nakajima, Hideo; Ikeda, Teruyuki

    Lotus-type porous copper is a form of copper that includes many straight pores, which are produced by the precipitation of supersaturated gas dissolved in the molten metal during solidification. The lotus-type porous copper is attractive as a heat sink because a higher heat transfer capacity is obtained as the pore diameter decreases. We investigate a fin model for predicting the heat transfer capacity of the lotus-type porous copper. Its heat transfer capacity is verified to be predictable via the straight fin model, in which heat conduction in the porous metal and the heat transfer to the fluid in the pores are taken into consideration by comparison with a numerical analysis. We both experimentally and analytically determine the heat transfer capacities of three types of heat sink: with conventional groove fins, with groove fins that have a smaller fin gap (micro-channels) and with lotus-type porous copper fins. The conventional groove fins have a fin gap of 3mm and a fin thickness of 1mm, the micro-channels have a fin gap of 0.5mm and a fin thickness of 0.5mm, and the lotus-type porous copper fins have pores with a diameter of 0.3mm and a porosity of 0.39. The lotus-type porous copper fins were found to have a heat transfer capacity 4 times greater than the conventional groove fins and 1.3 times greater than the micro-channel heat sink under the same pumping power.

  15. RNA-Seq Uncovers SNPs and Alternative Splicing Events in Asian Lotus (Nelumbo nucifera).

    PubMed

    Yang, Mei; Xu, Liming; Liu, Yanling; Yang, Pingfang

    2015-01-01

    RNA-Seq is an efficient way to comprehensively identify single nucleotide polymorphisms (SNPs) and alternative splicing (AS) events from the expressed genes. In this study, we conducted transcriptome sequencing of four Asian lotus (Nelumbo nucifera) cultivars using Illumina HiSeq2000 platform to identify SNPs and AS events in lotus. A total of 505 million pair-end RNA-Seq reads were generated from four cultivars, of which 86% were mapped to the lotus reference genome. Using the four sets of data together, a total of 357,689 putative SNPs were identified with an average density of one SNP per 2.2 kb. These SNPs were located in 1,253 scaffolds and 15,016 expressed genes. A/G and C/T were the two major types of SNPs in the Asian lotus transcriptome. In parallel, a total of 177,540 AS events were detected in the four cultivars and were distributed in 64% of the expressed genes of lotus. The predominant type of AS events was alternative 5' first exon, which accounted for 41.2% of all the observed AS events, and exon skipping only accounted for 4.3% of all AS. Gene Ontology analysis was conducted to analyze the function of the genes containing SNPs and AS events. Validation of selected SNPs and AS events revealed that 74% of SNPs and 80% of AS events were reliable, which indicates that RNA-Seq is an efficient approach to uncover gene-associated SNPs and AS events. A large number of SNPs and AS events identified in our study will facilitate further genetic and functional genomics research in lotus. PMID:25928215

  16. The soybean (Glycine max) nodulation-suppressive CLE peptide, GmRIC1, functions interspecifically in common white bean (Phaseolus vulgaris), but not in a supernodulating line mutated in the receptor PvNARK.

    PubMed

    Ferguson, Brett J; Li, Dongxue; Hastwell, April H; Reid, Dugald E; Li, Yupeng; Jackson, Scott A; Gresshoff, Peter M

    2014-10-01

    Legume plants regulate the number of nitrogen-fixing root nodules they form via a process called the Autoregulation of Nodulation (AON). Despite being one of the most economically important and abundantly consumed legumes, little is known about the AON pathway of common bean (Phaseolus vulgaris). We used comparative- and functional-genomic approaches to identify central components in the AON pathway of common bean. This includes identifying PvNARK, which encodes a LRR receptor kinase that acts to regulate root nodule numbers. A novel, truncated version of the gene was identified directly upstream of PvNARK, similar to Medicago truncatula, but not seen in Lotus japonicus or soybean. Two mutant alleles of PvNARK were identified that cause a classic shoot-controlled and nitrate-tolerant supernodulation phenotype. Homeologous over-expression of the nodulation-suppressive CLE peptide-encoding soybean gene, GmRIC1, abolished nodulation in wild-type bean, but had no discernible effect on PvNARK-mutant plants. This demonstrates that soybean GmRIC1 can function interspecifically in bean, acting in a PvNARK-dependent manner. Identification of bean PvRIC1, PvRIC2 and PvNIC1, orthologues of the soybean nodulation-suppressive CLE peptides, revealed a high degree of conservation, particularly in the CLE domain. Overall, our work identified four new components of bean nodulation control and a truncated copy of PvNARK, discovered the mutation responsible for two supernodulating bean mutants and demonstrated that soybean GmRIC1 can function in the AON pathway of bean. PMID:25040127

  17. Bicuspid Aortic Stenosis Treated With the Repositionable and Retrievable Lotus Valve.

    PubMed

    Seeger, Julia; Gonska, Birgid; Rodewald, Christoph; Rottbauer, Wolfgang; Wöhrle, Jochen

    2016-01-01

    Transcatheter aortic valve implantation (TAVI) for severe aortic stenosis is a well-established and safe therapeutic option. However, data on TAVI in bicuspid aortic valve stenosis are limited and show a higher rate of moderate-severe aortic regurgitation compared with TAVI for tricuspid aortic valve stenosis. We report for the first time, to our knowledge, the use of the mechanically deployed Lotus valve in bicuspid aortic stenosis. In our patient who had severe bicuspid aortic stenosis and was at high surgical risk, the implantation of the repositionable and completely retrievable Lotus valve was a safe and controlled procedure resulting in no relevant aortic regurgitation. PMID:26604121

  18. Production of exopolysaccharide from rhizobia with potential biotechnological and bioremediation applications.

    PubMed

    Castellane, Tereza Cristina Luque; Persona, Michelli Romanoli; Campanharo, João Carlos; de Macedo Lemos, Eliana Gertrudes

    2015-03-01

    The potential use of rhizobia under controlled fermentation conditions may result in the production of new extracellular polymeric substances (EPS) having novel and superior properties that will open up new areas of industrial applications and thus increase their demand. The production of EPS and the stability of emulsions formed with soybean oil, diesel oil and toluene using different concentrations of purified EPS derived from wild-type and mutant strains of Rhizobium tropici SEMIA 4077 was investigated. The EPS was defined as a heteropolysaccharide composed of six constituent monosaccharides that displayed higher intrinsic viscosity and pseudoplastic non-Newtonian fluid behavior in an aqueous solution. The ratio between the total EPS production and the cellular biomass was 76.70 for the 4077::Z04 mutant strain and only 8.10 for the wild-type strain. The EPS produced by the wild-type R. tropici SEMIA 4077 resulted in more stable emulsions with the tested toluene than xanthan gum, and the emulsification indexes with hydrocarbons and soybean oil were higher than 50%, indicating strong emulsion-stabilizing capacity. These results demonstrate that the EPS of R. tropici strains could be attractive for use in industrial and environmental applications, as it had higher intrinsic viscosity and good emulsification activity. PMID:25592842

  19. [Studies on fermentation conditions of cytokinin produced by rhizobia strain 4012a].

    PubMed

    Jia, X; Chen, S; Min, H; Qian, Z

    1998-06-01

    The conditions of cytokinin fermentation of the rhizobia strain 4012a were detected by the ELISA. The results indicated that the optimal medium for cytokinin production by strain 4012a was composed of glucose 10 g/L, (NH4)2SO4 1.0, K2HPO4.3H2O 0.6, MgSO4.7H2O 0.1, CaCl2.2H2O 0.4, FeCl3.6H2O 0.04, Na2MoO4.2H2O 0.1 mg/L, calcium pantothenate 100 micrograms/L, adenine 200 mg/L. When strain 4012a was grown in 250 ml flask containing 50 ml of the medium on the rotary shaker (150 r/min) at 27 degrees C for 96 h, the yield of CTK 908 micrograms/L culture solution was obtained. It displayed bioactivity kinetin equivalents (KE) 1 mg/L medium with the radish cotyledon expansion test. PMID:12549336

  20. Chemical and rheological properties of exopolysaccharides produced by four isolates of rhizobia.

    PubMed

    Moretto, Cristiane; Castellane, Tereza Cristina Luque; Lopes, Erica Mendes; Omori, Wellington Pine; Sacco, Laís Postai; Lemos, Eliana Gertrudes de Macedo

    2015-11-01

    The rheological, physicochemical properties, emulsification and stability of exopolysaccharides (EPSs) from four rhizobia isolates (LBMP-C01, LBMP-C02, LBMP-C03 and LBMP-C04) were studied. The EPS yields of isolates under these experimental conditions were in the range of 1.5-6.63gL(-1). The LBMP-C04 isolate, which presented the highest EPS production (6.63gL(-1)), was isolated from Arachis pintoi and was identified as a Rhizobium sp. strain that could be explored as a possible potential source for the production of extracellular heteropolysaccharides. All polymers showed a pseudoplastic non-Newtonian fluid behavior or shear thinning property in aqueous solutions. Among the four EPS tested against hydrocarbons, EPS LBMP-C01 was found to be more effective against hexane, olive and soybean oils (89.94%, 82.75% and 81.15%, respectively). Importantly, we found that changes in pH (2-11) and salinity (0-30%) influenced the emulsification of diesel oil by the EPSs. EPSLBMP-C04 presented optimal emulsification capacity at pH 10 (E24=53%) and 30% salinity (E24=27%). These findings contribute to the understanding of the influence of the chemical composition, physical properties and biotechnology applications of rhizobial EPS solutions their bioemulsifying properties. PMID:26234581

  1. Automatic two-step detection of pulmonary nodules

    NASA Astrophysics Data System (ADS)

    Dolejší, Martin; Kybic, Jan

    2007-03-01

    We present a computer-aided diagnosis (CAD) system to detect small-size (from 2mm to around 10mm) pulmonary nodules from helical CT scans. A pulmonary nodule is a small, round (parenchymal nodule) or worm (juxta-pleural) shaped lesion in the lungs. Both have greater radio density than lungs parenchyma. Lung nodules may indicate a lung cancer and its detection in early stage improves survival rate of patients. CT is considered to be the most accurate imaging modality for detection of nodules. However, the large amount of data per examination makes the interpretation difficult. This leads to omission of nodules by human radiologist. CAD system presented is designed to help lower the number of omissions. Our system uses two different schemes to locate juxtapleural nodules and parenchymal nodules. For juxtapleural nodules, morphological closing and thresholding is used to find nodule candidates. To locate non-pleural nodule candidates, 3D blob detector uses multiscale filtration. Ellipsoid model is fitted on nodules. To define which of the nodule candidates are in fact nodules, an additional classification step is applied. Linear and multi-threshold classifiers are used. System was tested on 18 cases (4853 slices) with total sensitivity of 96%, with about 12 false positives/slice. The classification step reduces number of false positives to 9 per slice without significantly decreasing sensitivity (89,6%).

  2. Pedobacter lotistagni sp. nov. isolated from lotus pond water.

    PubMed

    Singh, Hina; Du, Juan; Ngo, Hien T T; Kim, Ki-Young; Yi, Tae-Hoo

    2015-04-01

    A light-yellow coloured, Gram-stain negative, rod-shaped, aerobic, non-motile bacterium, designated THG-DN6.8(T), was isolated from a lotus pond near Donghaksa temple in Daejeon, South Korea. The strain was found to grow well on nutrient agar, optimally at pH 6.0-7.5, at temperature 25-28 °C and in the presence of 0.5 % NaCl. Based on 16S rRNA gene sequence analysis, strain THG-DN6.8(T) was found to share the highest sequence similarity with Pedobacter koreensis KCTC 12536(T), followed by Pedobacter glacialis CCTCC AB 2012941(T), Pedobacter kyungheensis KACC 16221(T), Pedobacter caeni LMG 22862(T), Pedobacter insulae KCTC 12820(T) and Pedobacter boryungensis KCTC 23344 (T). The DNA G+C content was determined to be 36.8 mol%. In DNA-DNA hybridization tests, the DNA relatedness between strain THG-DN6.8(T) and its closest phylogenetic neighbour P. koreensis was found to be below 10 %. The predominant isoprenoid quinone was identified as menaquinone MK-7 and the major polar lipid as phosphatidylethanolamine. The major fatty acids of strain THG-DN6.8(T) were identified as iso-C15:0, C16:0, C18:0 and C16:1 ω6c and/or C16:1 ω7c (summed feature 3). On the basis of the phenotypic characteristics, genotypic analysis and chemotaxonomic characteristics, strain THG-DN6.8(T) is considered to represent a novel species of the genus Pedobacter, for which the name Pedobacter lotistagni sp. nov. is proposed. The type strain is THG-DN6.8(T) (= KCTC 42229(T) = JCM 30354(T)). PMID:25613852

  3. Impact of defoliation intensities on plant biomass, nutrient uptake and arbuscular mycorrhizal symbiosis in Lotus tenuis growing in a saline-sodic soil.

    PubMed

    García, I; Mendoza, R

    2012-11-01

    The impact of different defoliation intensities on the ability of Lotus tenuis plants to regrowth, mobilise nutrients and to associate with native AM fungi and Rhizobium in a saline-sodic soil was investigated. After 70 days, plants were subjected to 0, 25, 50, 75 and 100% defoliation and shoot regrowth was assessed at the end of subsequent 35 days. Compared to non-defoliated plants, low or moderate defoliation up to 75% did not affect shoot regrowth. However, 100% treatment affected shoot regrowth and the clipped plants were not able to compensate the growth attained by non-defoliated plants. Root growth was more affected by defoliation than shoot growth. P and N concentrations in shoots and roots increased with increasing defoliation while Na(+) concentration in shoots of non-defoliated and moderately defoliated plants was similar. Non-defoliated and moderately defoliated plants prevented increases of Na(+) concentration in shoots through both reducing Na(+) uptake and Na(+) transport to shoots by accumulating Na(+) in roots. At high defoliation, the salinity tolerance mechanism is altered and Na(+) concentration in shoots was higher than in roots. Reduction in the photosynthetic capacity induced by defoliation neither changed the root length colonised by AM fungi nor arbuscular colonisation but decreased the vesicular colonisation. Spore density did not change, but hyphal density and Rhizobium nodules increased with defoliation. The strategy of the AM symbiont consists in investing most of the C resources to preferentially retain arbuscular colonisation as well as inoculum density in the soil. PMID:22512871

  4. Diversity and phylogeny of rhizobia associated with Desmodium spp. in Panxi, Sichuan, China.

    PubMed

    Xu, Kai Wei; Zou, Lan; Penttinen, Petri; Zeng, Xiangzhong; Liu, Ming; Zhao, Ke; Chen, Cuiping; Chen, Yuan Xue; Zhang, Xiaoping

    2016-02-01

    Thirty-four rhizobial isolates were obtained from root nodules of four wild Desmodium species growing in Panxi, Sichuan, China. According to the combined ARDRA and IGS-RFLP (CACAI) cluster analysis, Rhizobium, Pararhizobium and Mesorhizobium isolates outnumbered Bradyrhizobium isolates. In general, the isolates representing the same species from the same site clustered together. Furthermore, the four Desmodium species were all nodulated by more than one rhizobial species. AFLP and phenotypic analyses showed that the 34 isolates represented at least 32 distinct strains. None of the strains were found from more than one site or host, indicating a high degree of rhizobial diversity in Panxi. In the multilocus sequence analysis, the isolates were assigned to Pararhizobium giardinii, Bradyrhizobium japonicum, Mesorhizobium septentrionale, and to undescribed species of the genera Rhizobium, Bradyrhizobium and Agrobacterium. PMID:26654528

  5. Enhanced N2-fixing ability of a deletion mutant of arctic rhizobia with sainfoin (Onobrychis viciifolia).

    PubMed

    Jain, D K; Bordeleau, L M

    1990-12-01

    Mutagenesis provoked by exposure at elevated temperature of the cold-adapted, arctic Rhizobium strain N31 resulted in the generation of five deletion mutants, which exhibited loss of their smaller plasmid (200 kb), whereas the larger plasmid (> 500 kb) was still present in all mutants. Deletion mutants did not show differences from the wild type in the antibiotic resistance pattern, the carbohydrates and organic acids utilization, and the growth rate at low temperature. However, deletion mutants differed from the wild type and among themselves in the ex planta nitrogenase activity, the nodulation index, and the symbiotic effectiveness. The deletion mutant N31.6rif (r) showed higher nodulation index and exhibited higher nitrogenase activity and symbiotic efficiency than the other deletion mutants and the wild type. The process of deletion mutation resulted in the improvement of an arctic Rhizobium strain having an earlier and higher symbiotic nitrogen fixation efficiency than the wild type. PMID:24221111

  6. Metabolomic and Proteomic Profiles Reveal the Dynamics of Primary Metabolism during Seed Development of Lotus (Nelumbo nucifera)

    PubMed Central

    Wang, Lei; Fu, Jinlei; Li, Ming; Fragner, Lena; Weckwerth, Wolfram; Yang, Pingfang

    2016-01-01

    Sacred lotus (Nelumbo nucifera) belongs to the Nelumbonaceae family. Its seeds are widely consumed in Asian countries as snacks or even medicine. Besides the market value, lotus seed also plays a crucial role in the lotus life cycle. Consequently, it is essential to gain a comprehensive understanding of the development of lotus seed. During its development, lotus seed undergoes cell division, expansion, reserve accumulation, desiccation, and maturation phases. We observed morphological and biochemical changes from 10 to 25 days after pollination (DAP) which corresponded to the reserve synthesis and accumulation phase. The volume of the seed expanded until 20 DAP with the color of the seed coat changing from yellow-green to dark green and gradually fading again. Starch and protein rapidly accumulated from 15 to 20 DAP. To further reveal metabolic adaptation, primary metabolites and proteins profiles were obtained using mass spectrometry based platforms. Metabolites and enzymes involved in sugar metabolism, glycolysis, TCA cycle and amino acid metabolism showed sequential dynamics enabling the clear separation of the different metabolic states during lotus seed development. The integration of the data revealed a highly significant metabolic switch at 15 DAP going through a transition of metabolically highly active tissue to the preparation of storage tissue. The results provide a reference data set for the evaluation of primary metabolism during lotus seed development. PMID:27375629

  7. Antiobesity and hypolipidemic effects of lotus leaf hot water extract with taurine supplementation in rats fed a high fat diet

    PubMed Central

    2010-01-01

    Background Lotus (Nelumbo nucifera) leaf has been used to treat obesity. The purpose of this study was to investigate the antiobesity and hypolipidemic effects of lotus leaf hot water extract with taurine supplementation in high fat diet-induced obese rats. Methods Four week-old male Sprague-Dawley rats were randomly divided into four groups with 8 rats in each group for a period of 6 weeks (normal diet, N group; high fat diet, HF group; high fat diet + lotus leaf hot water extract, HFL group; high fat diet + lotus leaf hot water extract + taurine, HFLT group). Lotus leaf hot water extract was orally administrated to HFL and HFLT groups and the same amount of distilled water was orally administered (400 mg/kg/day) to N and HF groups. Taurine was supplemented by dissolving in feed water (3% w/v). Results The body weight gain and relative weights of epididymal and retroperitoneal adipose tissues were significantly lower in N, HFL and HFLT groups compared to HF group. HFL and HFLT groups showed lower concentrations of total cholesterol, triglyceride and low density lipoprotein cholesterol in serum. HFLT group showed higher the ratio of high density lipoprotein cholesterol/total cholesterol compared to HFL group. HFLT group showed better blood lipid profiles compared to HFL group. Conclusions Lotus leaf hot water extract with taurine supplementation showed antiobesity and hypolipidemic effects in high fat diet-induced obese rats, which was more effective than lotus leaf hot water extract alone. PMID:20804619

  8. Metabolomic and Proteomic Profiles Reveal the Dynamics of Primary Metabolism during Seed Development of Lotus (Nelumbo nucifera).

    PubMed

    Wang, Lei; Fu, Jinlei; Li, Ming; Fragner, Lena; Weckwerth, Wolfram; Yang, Pingfang

    2016-01-01

    Sacred lotus (Nelumbo nucifera) belongs to the Nelumbonaceae family. Its seeds are widely consumed in Asian countries as snacks or even medicine. Besides the market value, lotus seed also plays a crucial role in the lotus life cycle. Consequently, it is essential to gain a comprehensive understanding of the development of lotus seed. During its development, lotus seed undergoes cell division, expansion, reserve accumulation, desiccation, and maturation phases. We observed morphological and biochemical changes from 10 to 25 days after pollination (DAP) which corresponded to the reserve synthesis and accumulation phase. The volume of the seed expanded until 20 DAP with the color of the seed coat changing from yellow-green to dark green and gradually fading again. Starch and protein rapidly accumulated from 15 to 20 DAP. To further reveal metabolic adaptation, primary metabolites and proteins profiles were obtained using mass spectrometry based platforms. Metabolites and enzymes involved in sugar metabolism, glycolysis, TCA cycle and amino acid metabolism showed sequential dynamics enabling the clear separation of the different metabolic states during lotus seed development. The integration of the data revealed a highly significant metabolic switch at 15 DAP going through a transition of metabolically highly active tissue to the preparation of storage tissue. The results provide a reference data set for the evaluation of primary metabolism during lotus seed development. PMID:27375629

  9. Evaluation of pulmonary nodules in Asian population

    PubMed Central

    Phua, Chee K.; Sim, Wen Y.; Sen Tee, Kuan; Lew, Sennen J. W.; Lim, Albert Y. H.; Tai, Dessmon Y. H.; Goh, Soon Keng; Kor, Ai Ching; Ng, Alan W. K.; Abisheganaden, John

    2016-01-01

    Background American College of Chest Physicians (ACCP) provides guidelines to manage pulmonary nodules. Pulmonary nodules however can be malignant or benign. Similar incidence of tuberculosis (TB) and lung cancer in Asian countries raises concern over the relevance of suggested guidelines in Asian population. There is little data on the pattern of clinical practice in the management of pulmonary nodules in Asian country (Singapore). Our study describes the current pattern of clinical practice in this area highlighting the variation in practice and discussing the potential reasons. Methods Retrospective review of the medical records of patients diagnosed with lung cancer in 2010. Results Sixty nodules were identified in 32 patients. Nodules were detected incidentally on routine imaging in 7 (21.9%) patients. TB contact tracing and pre-employment screening were common ways by which nodules were detected incidentally. Over one third (37.5%) were non-smokers. Majority of nodules were located in the upper lobes of right and left lung followed by right lower lobe (RLL). Only few patients 8 (25%) had positron emission tomography (PET) scan for staging purposes. There were no difference in survival between patients who presented with single, 747 (range, 25–1,840) days vs. multiple nodules 928 (range, 30–2,572) days, P=0.26. In a retrospective analysis of malignancy risk with the probability calculator, 62.5% patients were at low-moderate risk whilst 32.5% were at high risk. Conclusions The clinical practice of managing pulmonary nodules in Asian population differs from ACCP guidelines. None of the patient had pre-test probability calculated, and few had PET scan. This is because upper lobe predominance of lung cancer is identical to TB, non-smoking history does not have any weight in discounting malignancy risk where many of the Asian lung cancer patients are non-smokers, and the local endemicity of TB and its confounding effect on radiological findings of CT scan and

  10. CT features of pleural masses and nodules.

    PubMed

    Reetz, Jennifer A; Buza, Elizabeth L; Krick, Erika L

    2012-01-01

    Pleural space masses and nodules are rarely described on computed tomography (CT) in veterinary medicine and have only been described in patients with neoplasia. Our purpose was to describe the CT findings and diagnoses in seven patients with pleural masses and nodules. Two patients had broad-based, plaque-like pleural masses, both of which were due to neoplasia (primary pleural carcinoma, metastatic thymoma). Two patients had well-defined pleural nodules and nodular pleural thickening, one of which had mesothelial hypertrophy, and another of which had metastatic hemangiosarcoma. Three patients had ill-defined pleural nodules to nodular pleural thickening, one of which had metastatic pulmonary carcinoma, while the other two had bacterial infection with mesothelial proliferation (n = 2), fibrinous pleuritis (n = 1), and severe mediastinal pleuritis/mediastinitis (n = 2). Five of the seven patients had focal, multifocal or diffuse smooth, and/or irregular pleural thickening. Five of seven patients had pleural effusion, and postcontrast CT was useful in several patients for delineating the pleural lesions from the effusion. All patients except one had additional lesions identified on CT besides those in the pleural space. CT is useful in identifying and characterizing pleural space lesions and could be used to guide further diagnostic procedures such as thoracoscopy or exploratory thoracotomy. Both neoplastic and nonneoplastic diseases should be considered in the differential diagnoses for pleural space masses and nodules found on CT. PMID:22092656

  11. Novel physiological insight into a lotus root appearance in stable coronary artery diseases; Report of two cases.

    PubMed

    Suzuki, Makoto; Seki, Atsushi; Nishikawa, Kei; Takamisawa, Itaru; Tobaru, Tetsuya; Sumiyoshi, Tetsuya

    2016-04-01

    So far physiological significance of multiple intraluminal channels separated by thin wall structures, so called "a lotus root appearance", in an angiographic insignificant lesion in patients with suspected angina pectoris has remained undetermined. Here we present two cases that showed a "reverse visual-functional mismatch" phenomenon of a lotus root appearance using the indexes of myocardial fractional flow reserve and/or coronary flow velocity reserve. Our findings may provide a novel physiological insight into a lotus root appearance as a high possibility of critical functional stenosis in those with stable coronary artery diseases. PMID:25749916

  12. In vitro corrosion resistance of Lotus-type porous Ni-free stainless steels.

    PubMed

    Alvarez, Kelly; Hyun, Soong-Keun; Fujimoto, Shinji; Nakajima, Hideo

    2008-11-01

    The corrosion behavior of three kinds of austenitic high nitrogen Lotus-type porous Ni-free stainless steels was examined in acellular simulated body fluid solutions and compared with type AISI 316L stainless steel. The corrosion resistance was evaluated by electrochemical techniques, the analysis of released metal ions was performed by inductively coupled plasma mass spectrometry (ICP-MS) and the cytotoxicity was investigated in a culture of murine osteoblasts cells. Total immunity to localized corrosion in simulated body fluid (SBF) solutions was exhibited by Lotus-type porous Ni-free stainless steels, while Lotus-type porous AISI 316L showed very low pitting corrosion resistance evidenced by pitting corrosion at a very low breakdown potential. Additionally, Lotus-type porous Ni-free stainless steels showed a quite low metal ion release in SBF solutions. Furthermore, cell culture studies showed that the fabricated materials were non-cytotoxic to mouse osteoblasts cell line. On the basis of these results, it can be concluded that the investigated alloys are biocompatible and corrosion resistant and a promising material for biomedical applications. PMID:18545945

  13. The mitochondrial genome of the American lotus borer, Ostrinia penitalis (Lepidoptera: Crambidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The American lotus borer, Ostrinia penitalis, is the most ancestral among more than 20 species described in the genus Ostrinia, and the near complete mitochondrial genome sequence described here is important for phylogenetic comparisons. The 12,612 bp contiguous fragment contains 13 protein coding ...

  14. Students' Alternative Conceptions about the Lotus Effect: To Confront or to Ignore?

    ERIC Educational Resources Information Center

    Kubisch, Franziska; Heyne, Thomas

    2016-01-01

    At the botanical garden of the University of Würzburg, we conducted practical lessons on bionics, focused on the lotus effect, with 260 students. Those approx. 14 years old, 8th-grade mid-level students were divided into two groups. During an instructional discussion about the topic, one group was confronted with their alternative conceptions…

  15. Contribution of the Alternative Pathway to Respiration during Thermogenesis in Flowers of the Sacred Lotus1

    PubMed Central

    Watling, Jennifer R.; Robinson, Sharon A.; Seymour, Roger S.

    2006-01-01

    We report results from in vivo measurements, using oxygen isotope discrimination techniques, of fluxes through the alternative and cytochrome respiratory pathways in thermogenic plant tissue, the floral receptacle of the sacred lotus (Nelumbo nucifera). Fluxes through both pathways were measured in thermoregulating flowers undergoing varying degrees of thermogenesis in response to ambient temperature. Significant increases in alternative pathway flux were found in lotus receptacles with temperatures 16°C to 20°C above ambient, but not in those with lesser amounts of heating. Alternative pathway flux in the hottest receptacles was 75% of the total respiratory flux. In contrast, fluxes through the cytochrome pathway did not change significantly during thermogenesis. These data support the hypothesis that increased flux through the alternative pathway is responsible for heating in the lotus and that it is unlikely that uncoupling proteins, which would have produced increased fluxes through the cytochrome pathway, contribute significantly to heating in this tissue. Comparisons of actual flux, with capacity determined using inhibitors, suggested that the alternative pathway was operating at close to maximum capacity in heating tissues of lotus. However, in nonheating tissues the inhibitor data significantly overestimated the alternative pathway flux. This confirms that isotopic measurements are necessary for accurate determination of fluxes through the two pathways. PMID:16461386

  16. Hydrogen sulfide inhibits enzymatic browning of fresh-cut lotus root slices by regulating phenolic metabolism.

    PubMed

    Sun, Ying; Zhang, Wei; Zeng, Tao; Nie, Qixing; Zhang, Fengying; Zhu, Liqin

    2015-06-15

    The effect of fumigation with hydrogen sulfide (H2S) gas on inhibiting enzymatic browning of fresh-cut lotus root slices was investigated. Browning degree, changes in color, total phenol content, superoxide anion production rate (O2(-)), H2O2 content, antioxidant capacities (DPPH radical scavenging ability, ABTS radical scavenging activity and the reducing power) and activities of the phenol metabolism-associated enzymes including phenylalanine ammonialyase (PAL), catalase (CAT), peroxidase (POD), polyphenol oxidase (PPO) were evaluated. The results showed that treatment with 15 μl L(-1) H2S significantly inhibited the browning of fresh-cut lotus root slices (P<0.05), reduced significantly O2(-) production rate and H2O2 content, and enhanced antioxidant capacities (P<0.05). PPO and POD activities in the fresh-cut lotus root slices were also significantly inhibited by treatment with H2S (P<0.05). This study suggested that treatment with exogenous H2S could inhibit the browning of fresh-cut lotus root slices by enhancing antioxidant capacities to alleviate the oxidative damage. PMID:25660900

  17. Welcome to Lotus 1-2-3 Advanced. Learning Activity Packets.

    ERIC Educational Resources Information Center

    Mills, Steven; And Others

    This learning activity packet (LAP) contains five self-paced study lessons that allow students to study advanced concepts of Lotus 1-2-3 at their own pace. The lessons used in the LAP are organized in the following way: lesson name, lesson number, objectives, completion standard, performance standard, required materials, unit test, and exercises.…

  18. Early Lotus japonicus root transcriptomic responses to symbiotic and pathogenic fungal exudates

    PubMed Central

    Giovannetti, Marco; Mari, Alfredo; Novero, Mara; Bonfante, Paola

    2015-01-01

    The objective of this study is to evaluate Lotus japonicus transcriptomic responses to arbuscular mycorrhizal (AM) germinated spore exudates (GSEs), responsible for activating nuclear Ca2+ spiking in plant root epidermis. A microarray experiment was performed comparing gene expression in Lotus rootlets treated with GSE or water after 24 and 48 h. The transcriptional pattern of selected genes that resulted to be regulated in the array was further evaluated upon different treatments and timings. In particular, Lotus rootlets were treated with: GSE from the pathogenic fungus Colletotrichum trifolii; short chitin oligomers (COs; acknowledged AM fungal signals) and long COs (as activators of pathogenic responses). This experimental set up has revealed that AM GSE generates a strong transcriptomic response in Lotus roots with an extensive defense-related response after 24 h and a subsequent down-regulation after 48 h. A similar subset of defense-related genes resulted to be up-regulated also upon treatment with C. trifolii GSE, although with an opposite trend. Surprisingly, long COs activated both defense-like and symbiosis-related genes. Among the genes regulated in the microarray, promoter-GUS assay showed that LjMATE1 activates in epidermal cells and root hairs. PMID:26175746

  19. Photosynthetic responses mediate the adaptation of two Lotus japonicus ecotypes to low temperature.

    PubMed

    Calzadilla, Pablo Ignacio; Signorelli, Santiago; Escaray, Francisco Jose; Menéndez, Ana Bernardina; Monza, Jorge; Ruiz, Oscar Adolfo; Maiale, Santiago Javier

    2016-09-01

    Lotus species are important forage legumes due to their high nutritional value and adaptability to marginal conditions. However, the dry matter production and regrowth rate of cultivable Lotus spp. is drastically reduced during colder seasons. In this work, we evaluated the chilling response of Lotus japonicus ecotypes MG-1 and MG-20. No significant increases were observed in reactive oxygen species and nitric oxide production or in lipid peroxidation, although a chilling-induced redox imbalance was suggested through NADPH/NADP(+) ratio alterations. Antioxidant enzyme catalase, ascorbate peroxidase, and superoxide dismutase activities were also measured. Superoxide dismutase, in particular the chloroplastic isoform, showed different activity for different ecotypes and treatments. Stress-induced photoinhibition also differentially influenced both ecotypes, with MG-1 more affected than MG-20. Data showed that the D2 PSII subunit was more affected than D1 after 1 d of low temperature exposure, although its protein levels recovered over the course of the experiment. Interestingly, D2 recovery was accompanied by improvements in photosynthetic parameters (Asat and Fv/Fm) and the NADPH/NADP(+) ratio. Our results suggest that the D2 protein is involved in the acclimation response of L. japonicus to low temperature. This may provide a deeper insight into the chilling tolerance mechanisms of the Lotus genus. PMID:27457984

  20. Legume genome evolution viewed through the Medicago truncatula and Lotus japonicus genomes

    PubMed Central

    Cannon, Steven B.; Sterck, Lieven; Rombauts, Stephane; Sato, Shusei; Cheung, Foo; Gouzy, Jérôme; Wang, Xiaohong; Mudge, Joann; Vasdewani, Jayprakash; Schiex, Thomas; Spannagl, Manuel; Monaghan, Erin; Nicholson, Christine; Humphray, Sean J.; Schoof, Heiko; Mayer, Klaus F. X.; Rogers, Jane; Quétier, Francis; Oldroyd, Giles E.; Debellé, Frédéric; Cook, Douglas R.; Retzel, Ernest F.; Roe, Bruce A.; Town, Christopher D.; Tabata, Satoshi; Van de Peer, Yves; Young, Nevin D.

    2006-01-01

    Genome sequencing of the model legumes, Medicago truncatula and Lotus japonicus, provides an opportunity for large-scale sequence-based comparison of two genomes in the same plant family. Here we report synteny comparisons between these species, including details about chromosome relationships, large-scale synteny blocks, microsynteny within blocks, and genome regions lacking clear correspondence. The Lotus and Medicago genomes share a minimum of 10 large-scale synteny blocks, each with substantial collinearity and frequently extending the length of whole chromosome arms. The proportion of genes syntenic and collinear within each synteny block is relatively homogeneous. Medicago–Lotus comparisons also indicate similar and largely homogeneous gene densities, although gene-containing regions in Mt occupy 20–30% more space than Lj counterparts, primarily because of larger numbers of Mt retrotransposons. Because the interpretation of genome comparisons is complicated by large-scale genome duplications, we describe synteny, synonymous substitutions and phylogenetic analyses to identify and date a probable whole-genome duplication event. There is no direct evidence for any recent large-scale genome duplication in either Medicago or Lotus but instead a duplication predating speciation. Phylogenetic comparisons place this duplication within the Rosid I clade, clearly after the split between legumes and Salicaceae (poplar). PMID:17003129

  1. The basic helix-loop-helix transcription factor family in the sacred lotus, Nelumbo nucifera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nelumbo nucifera (Sacred Lotus) is a basal eudicot with exceptional physiological and metabolic properties including seed longevity, adaptations for an aquatic habit, and floral thermiogenesis. It also occupies a unique position in the phylogeny of land plants and can be a useful species for studies...

  2. Deep-ocean ferromanganese crusts and nodules

    USGS Publications Warehouse

    Hein, James R.; Koschinsky, Andrea

    2013-01-01

    Ferromanganese crusts and nodules may provide a future resource for a large variety of metals, including many that are essential for emerging high- and green-technology applications. A brief review of nodules and crusts provides a setting for a discussion on the latest (past 10 years) research related to the geochemistry of sequestration of metals from seawater. Special attention is given to cobalt, nickel, titanium, rare earth elements and yttrium, bismuth, platinum, tungsten, tantalum, hafnium, tellurium, molybdenum, niobium, zirconium, and lithium. Sequestration from seawater by sorption, surface oxidation, substitution, and precipitation of discrete phases is discussed. Mechanisms of metal enrichment reflect modes of formation of the crusts and nodules, such as hydrogenetic (from seawater), diagenetic (from porewaters), and mixed diagenetic–hydrogenetic processes.

  3. Diagnosis and management of pulmonary nodules.

    PubMed

    Krochmal, Rebecca; Arias, Sixto; Yarmus, Lonny; Feller-Kopman, David; Lee, Hans

    2014-12-01

    There are an increased number of pulmonary nodules discovered on CT scan images in part due to those performed for lung cancer screening. Risk stratification and patient involvement is critical in determining management ranging from interval imaging to invasive biopsy or surgery. A definitive diagnosis requires tissue biopsy. The choice of a particular biopsy technique depends on the risks/benefits of the procedure, the diagnostic yield and local expertise. This review will focus on the evaluation and management of pulmonary nodules based on the Fleischner Society and American College of Chest Physician guidelines. There have been recent changes to both societies' recommendations for incidental detection of solid and subsolid nodules, risk stratification, imaging, minimally invasive diagnostic techniques and definitive surgical options. PMID:25152306

  4. Multiple cutaneous, oropharyngeal and pulmonary nodules.

    PubMed

    Veraitch, O; Bhargava, K; Moriarty, B; Calonje, E; Mallipeddi, R; Whittaker, S

    2015-08-01

    Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis defined by heterogeneous multiorgan involvement. Due to the rarity of this disease strong evidence-based therapies have yet to be established and prognosis has previously been considered to be poor, with more than half of patients dying within 3 years of initial presentation. We describe an 86-year-old woman with a 34-year history of extensive cutaneous and internal nodules with typical pathological and immunophenotypical (CD68(+) /CD1a(-) ) features of ECD without evidence of the BRAF V600E mutation. The cosmetic appearance of cutaneous nodules and hoarse voice caused by vocal cord nodules has been managed surgically. More aggressive therapies reported for ECD were trialled for this patient, such as radiotherapy and interferon-α, with no response. This case demonstrates a relatively good prognosis in ECD that has been managed conservatively. PMID:25639756

  5. Endometrial Stromal Nodule: Report of a Case

    PubMed Central

    Fdili Alaoui, F. Z.; Chaara, H.; Bouguern, H.; Melhouf, M. A.; Fatemi, H.; Belmlih, A.; Amarti, A.

    2011-01-01

    Endometrial stromal nodule (ESN) is the least common of the endometrial stromal tumors. They are rare neoplasms which are diagnosed in most instances by light microscopy. Although such nodules are benign, hysterectomy has been considered the treatment of choice to determine the margins of the tumor required for diagnosis and to differentiate it from invasive stromal sarcoma Whose prognosis is totally different. We report a case of a 45 years old woman, with presurgical diagnosis of adnexal mass or uterine tumor. She underwent a total abdominal hysterectomy. Pathologic examination revealed an endometrial stromal nodule. Through this observation, we insist on the fact that the ESNs are rare and benign entities which must be differentiated from the other invasive malignant stromal tumors; this can change the final prognosis. PMID:21423543

  6. Endometrial stromal nodule: report of a case.

    PubMed

    Fdili Alaoui, F Z; Chaara, H; Bouguern, H; Melhouf, M A; Fatemi, H; Belmlih, A; Amarti, A

    2011-01-01

    Endometrial stromal nodule (ESN) is the least common of the endometrial stromal tumors. They are rare neoplasms which are diagnosed in most instances by light microscopy. Although such nodules are benign, hysterectomy has been considered the treatment of choice to determine the margins of the tumor required for diagnosis and to differentiate it from invasive stromal sarcoma Whose prognosis is totally different. We report a case of a 45 years old woman, with presurgical diagnosis of adnexal mass or uterine tumor. She underwent a total abdominal hysterectomy. Pathologic examination revealed an endometrial stromal nodule. Through this observation, we insist on the fact that the ESNs are rare and benign entities which must be differentiated from the other invasive malignant stromal tumors; this can change the final prognosis. PMID:21423543

  7. Nodules Initiated by Rhizobium meliloti Exopolysaccharide Mutants Lack a Discrete, Persistent Nodule Meristem 1

    PubMed Central

    Yang, Cheng; Signer, Ethan R.; Hirsch, Ann M.

    1992-01-01

    Infection of alfalfa with Rhizobium meliloti exo mutants deficient in exopolysaccharide results in abnormal root nodules that are devoid of bacteria and fail to fix nitrogen. Here we report further characterization of these abnormal nodules. Tightly curled root hairs or shepherd's crooks were found after inoculation with Rm 1021-derived exo mutants, but curling was delayed compared with wild-type Rm 1021. Infection threads were initiated in curled root hairs by mutants as well as by wild-type R. meliloti, but the exo mutant-induced threads aborted within the peripheral cells of the developing nodule. Also, nodules elicited by Rm 1021-derived exo mutants were more likely to develop on secondary roots than on the primary root. In contrast with wild-type R. meliloti-induced nodules, the exo mutant-induced nodules lacked a well defined apical meristem, presumably due to the abortion of the infection threads. The relationship of these findings to the physiology of nodule development is discussed. ImagesFigure 3Figure 1Figure 2Figure 4 PMID:16668605

  8. Penile nodule in a young adult.

    PubMed

    Choudhury, S R; Maji, B P

    1990-06-01

    A 20 year old male presented with a nodule, 1.25 cm x 1 cm, on the ventral aspect of the foreskin of his penis. The nodule was excised by circumcision. On histology it was found to be a multiloculated cyst located in the dermis of the prepuce. It contained eosinophilic material and was lined by pseudostratified columnar epithelium. There was no evidence of inflammation or malignancy in any of the sections of this median raphe cyst. The aetiology of such cysts is discussed in addition to a review of the literature. PMID:2346443

  9. Radiofrequency ablation for benign thyroid nodules.

    PubMed

    Bernardi, S; Stacul, F; Zecchin, M; Dobrinja, C; Zanconati, F; Fabris, B

    2016-09-01

    Benign thyroid nodules are an extremely common occurrence. Radiofrequency ablation (RFA) is gaining ground as an effective technique for their treatment, in case they become symptomatic. Here we review what are the current indications to RFA, its outcomes in terms of efficacy, tolerability, and cost, and also how it compares to the other conventional and experimental treatment modalities for benign thyroid nodules. Moreover, we will also address the issue of treating with this technique patients with cardiac pacemakers (PM) or implantable cardioverter-defibrillators (ICD), as it is a rather frequent occurrence that has never been addressed in detail in the literature. PMID:27098804

  10. Pulmonary carcinoid presenting as multiple subcutaneous nodules.

    PubMed

    Oleksowicz, L; Morris, J C; Phelps, R G; Bruckner, H W

    1990-02-28

    A 60-year-old female presented with a one-year history of multiple enlarging tender subcutaneous nodules. Initial biopsy demonstrated a poorly differentiated adenocarcinoma. Mammography showed multiple nodular breast lesions. After the patient failed to respond to tamoxifen, a second biopsy demonstrated a metastatic carcinoid tumor. Further search revealed a single small pulmonary nodule, which on aspiration biopsy proved to be a carcinoid tumor. The patient failed to respond to treatment with streptozotocin and 5'-fluorouracil. Therapy with leucovorin calcium and 5'-fluorouracil then produced a partial response. PMID:2321273

  11. Genome of the long-living sacred lotus (Nelumbo nucifera Gaertn.)

    PubMed Central

    2013-01-01

    Background Sacred lotus is a basal eudicot with agricultural, medicinal, cultural and religious importance. It was domesticated in Asia about 7,000 years ago, and cultivated for its rhizomes and seeds as a food crop. It is particularly noted for its 1,300-year seed longevity and exceptional water repellency, known as the lotus effect. The latter property is due to the nanoscopic closely packed protuberances of its self-cleaning leaf surface, which have been adapted for the manufacture of a self-cleaning industrial paint, Lotusan. Results The genome of the China Antique variety of the sacred lotus was sequenced with Illumina and 454 technologies, at respective depths of 101× and 5.2×. The final assembly has a contig N50 of 38.8 kbp and a scaffold N50 of 3.4 Mbp, and covers 86.5% of the estimated 929 Mbp total genome size. The genome notably lacks the paleo-triplication observed in other eudicots, but reveals a lineage-specific duplication. The genome has evidence of slow evolution, with a 30% slower nucleotide mutation rate than observed in grape. Comparisons of the available sequenced genomes suggest a minimum gene set for vascular plants of 4,223 genes. Strikingly, the sacred lotus has 16 COG2132 multi-copper oxidase family proteins with root-specific expression; these are involved in root meristem phosphate starvation, reflecting adaptation to limited nutrient availability in an aquatic environment. Conclusions The slow nucleotide substitution rate makes the sacred lotus a better resource than the current standard, grape, for reconstructing the pan-eudicot genome, and should therefore accelerate comparative analysis between eudicots and monocots. PMID:23663246

  12. [Evolution of Root Nodule Bacteria: Reconstruction of the Speciation Processes Resulting from Genomic Rearrangements in a Symbiotic System].

    PubMed

    Provorov, N A; Andronov, E E

    2016-01-01

    The processes of speciation and macroevolution of root nodule bacteria (rhizobia), based on deep rearrangements of their genomes and occurring in the N₂-fixing symbiotic system, are reconstructed. At the first stage of rhizobial evolution, transformation of free-living diazotrophs (related to Rhodopseudomonas) to symbiotic N₂-fixers (Bradyrhizobium) occurred due to the acquisition of the fix gene system, which is responsible for providing nitrogenase with electrons and reducing equivalents, as well as for oxygen-dependent regulation of nitrogenase synthesis in planta, and then of the nod genes responsible for the synthesis of the lipo- chito-oligosaccharide Nod factors, which induce root nodule development. The subsequent rearrangements of bacterial genomes included: (1) increased volume of hereditary information supported by species, genera (pan-genome), and individual strains; (2) transition from the unitary genome to a multicomponent one; and (3) enhanced levels of bacterial genetic plasticity and horizontal gene transfer, resulting in formation of new genera, of which Mesorhizobium, Rhizobium, and Sinorhizobium are the largest, and of over 100 species. Rhizobial evolution caused by development and diversification of the Nod factor synthesizing systems may result in both increased host specificity range (transition of Bradyrhizobium from autotrophic to symbiotrophic carbon metabolism in interaction with a broad spectrum of legumes) and to its contraction (transition of Rhizobium and Sinorhizobium to "altruistic" interaction with legumes of the galegoid clade). Reconstruction of the evolutionary pathway from symbiotic N₂-fixers to their free-living ancestors makes it possible to initiate the studies based on up-to-date genome screening technologies and aimed at the issues of genetic integration of organisms into supracpecies complexes, ratios of the macro- and microevolutionary mechanisms, and developmetn of cooperative adaptations based on altruistic

  13. Functional analysis of duplicated Symbiosis Receptor Kinase (SymRK) genes during nodulation and mycorrhizal infection in soybean (Glycine max).

    PubMed

    Indrasumunar, Arief; Wilde, Julia; Hayashi, Satomi; Li, Dongxue; Gresshoff, Peter M

    2015-03-15

    Association between legumes and rhizobia results in the formation of root nodules, where symbiotic nitrogen fixation occurs. The early stages of this association involve a complex of signalling events between the host and microsymbiont. Several genes dealing with early signal transduction have been cloned, and one of them encodes the leucine-rich repeat (LRR) receptor kinase (SymRK; also termed NORK). The Symbiosis Receptor Kinase gene is required by legumes to establish a root endosymbiosis with Rhizobium bacteria as well as mycorrhizal fungi. Using degenerate primer and BAC sequencing, we cloned duplicated SymRK homeologues in soybean called GmSymRKα and GmSymRKβ. These duplicated genes have high similarity of nucleotide (96%) and amino acid sequence (95%). Sequence analysis predicted a malectin-like domain within the extracellular domain of both genes. Several putative cis-acting elements were found in promoter regions of GmSymRKα and GmSymRKβ, suggesting a participation in lateral root development, cell division and peribacteroid membrane formation. The mutant of SymRK genes is not available in soybean; therefore, to know the functions of these genes, RNA interference (RNAi) of these duplicated genes was performed. For this purpose, RNAi construct of each gene was generated and introduced into the soybean genome by Agrobacterium rhizogenes-mediated hairy root transformation. RNAi of GmSymRKβ gene resulted in an increased reduction of nodulation and mycorrhizal infection than RNAi of GmSymRKα, suggesting it has the major activity of the duplicated gene pair. The results from the important crop legume soybean confirm the joint phenotypic action of GmSymRK genes in both mycorrhizal and rhizobial infection seen in model legumes. PMID:25617765

  14. Rhizobium qilianshanense sp. nov., a novel species isolated from root nodule of Oxytropis ochrocephala Bunge in China.

    PubMed

    Xu, Lin; Zhang, Yong; Deng, Zheng Shan; Zhao, Liang; Wei, Xiu Li; Wei, Ge Hong

    2013-03-01

    During a study of the diversity and phylogeny of rhizobia isolated from root nodules of Oxytropis ochrocephala grown in the northwest of China, four strains were classified in the genus Rhizobium on the basis of their 16S rRNA gene sequences. These strains have identical 16S rRNA gene sequences, which showed a mean similarity of 94.4 % with the most closely related species, Rhizobium oryzae. Analysis of recA and glnA sequences showed that these strains have less than 88.1 and 88.7 % similarity with the defined species of Rhizobium, respectively. The genetic diversity revealed by ERIC-PCR fingerprinting indicated that the isolates correspond to different strains. Strain CCNWQLS01(T) contains Q-10 as the predominant ubiquinone. The major fatty acids were identified as feature 8 (C18: 1ω7c and/or C18: 1ω6c; 67.2 %). Therefore, a novel species Rhizobium qilianshanense sp. nov. is proposed, and CCNWQLS01(T) (= ACCC 05747(T) = JCM 18337(T)) is designated as the type strain. PMID:23142858

  15. Diversity of endophytic bacteria associated with nodules of two indigenous legumes at different altitudes of the Qilian Mountains in China.

    PubMed

    Xu, Lin; Zhang, Yong; Wang, Li; Chen, Weimin; Wei, Gehong

    2014-09-01

    A total of 201 endophytic root nodule-associated bacteria collected from two legumes indigenous to different Qilian Mountain altitudes (Hexi Corridor) were characterized through 16S rDNA polymerase chain reaction (PCR)-restriction fragment length polymorphism, 16S rRNA gene sequence analysis, and enterobacterial repetitive intergenic consensus-PCR clustering. The isolates phylogenetically belonged to 35 species in the Phyllobacterium, Ensifer, Rhizobium, Microvirga, Sphingomonas, Paracoccus, Mycobacterium, Paenibacillus, Cohnella, Sporosarcina, Bacillus, Staphylococcus, Brevibacterium, Xenophilus, Erwinia, Leclercia, Acinetobacter, and Pseudomonas genera. Phylogenetic nodA sequence analysis showed higher similarity to Sinorhizobium meliloti with strains related to the Rhizobium, Sinorhizobium, and Acinetobacter genera. Sequence analysis of the nifH gene revealed that the strains belonging to Xenophilus, Acinetobacter, Phyllobacterium, and Rhizobium had genes similar to those of Mesorhizobium and Sinorhizobium. The results indicated that horizontal gene transfer could have occurred between rhizobia and non-rhizobial endophytes. Canonical correspondence analysis revealed that altitude and host plant species contributed more to the bacterial endosymbiont separation than other ecological factors. This study provided valuable information on the interactions between symbiotic bacteria, non-symbiotic bacteria and their habitats, and thus provided knowledge on their genetic diversity and ecology. PMID:24985194

  16. Infection and nodulation of clover by nonmotile Rhizobium trifolii

    SciTech Connect

    Napoli, C.; Albersheim, P.

    1980-02-01

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

  17. Comparative analysis of antioxidant activity and functional components of the ethanol extract of lotus (Nelumbo nucifera) from various growing regions.

    PubMed

    Zhao, Xu; Shen, Jian; Chang, Kyung Ja; Kim, Sung Hoon

    2014-07-01

    The variations in antioxidant activity and concentration of functional components in the ethanol extracts of lotus seeds and rhizomes based on the growing region and dryness were investigated. Free radical scavenging activity, total phenolic and flavonoid content, and concentration of several specific flavonoids and alkaloids in the ethanol extracts of lotus were measured. Antioxidant activity and its correlative total phenolic content varied characteristically depending on the growing region and dryness. High-perfomance liquid chromatography analysis showed that the ethanol extracts of lotus seeds from Vietnam (Ho Chi Minh City), raw rhizomes from Korea (Siheung), and dried rhizomes from Japan (Nigata) had the greatest specific flavonoid content. The ethanol extracts of seeds from China (Hubei), raw rhizomes from Japan (Nigata), and dried rhizomes from Korea (Siheung) had the greatest specific alkaloid content. Astragaline, rutin, isoquercetin, nuciferine, dauricine, isoliensinine, and neferine were identified in lotus rhizomes for the first time in this study. PMID:24932940

  18. CARBON AND NITROGEN METABOLISM IN LEGUME NODULES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Symbiotic root nodules are in essence highly integrated factories for C utilization and N assimilation. Significant progress has been made in physical, biochemical, and molecular characterization of the primary enzymes involved in C utilization and amide N assimilation. Recent advances in genomic me...

  19. Manganese nodules: thorium-230: protactinium-231 ratios.

    PubMed

    Sackett, W M

    1966-11-01

    The Th(230): Pa(231) activity ratio in 7 of 11 manganese nodules is less than 10.8, the theoretical production ratio of activities in the ocean. This finding indicates difierential accumulation of these nuclides in authigenic deposits of manganese-iron oxide. PMID:17778807

  20. Vocal Nodules: Their Cause and Treatment

    ERIC Educational Resources Information Center

    Teter, Darrel L.

    1977-01-01

    Provides knowledge about the workings of the vocal apparatus, the scientific basis of certain vocal problems, and what to do to overcome those problems. Specifically discusses the occurrence of nodules on the vocal cords and how to treat them, a subject of interest to both singers and nonsingers. (Editor/RK)

  1. Milker’s nodule - Case report*

    PubMed Central

    Adriano, André Ricardo; Quiroz, Carlos Daniel; Acosta, Martha Liliana; Jeunon, Thiago; Bonini, Flávia

    2015-01-01

    Milker's nodule is an occupational viral skin disease of universal distribution, caused by the Paravaccinia virus and that occurs in individuals who deal with dairy cattle herds. We describe a case acquired due to lack of use of PPE (Personal Protective Equipment) and perform a literature review. PMID:26131876

  2. Computerized interpretation of solitary pulmonary nodules

    NASA Astrophysics Data System (ADS)

    Suzuki, Hideo; Takabatake, Hirotsugu; Mori, Masaki; Mitani, Masanobu; Natori, Hiroshi

    1998-04-01

    In physicians' interpretation, morphologic characteristics of pulmonary nodules are not only important signs for the discrimination, but also important features for the diagnosis with a reasonable degree of confidence. This paper describes about the computerized interpretation system which is developed to analyze the relation between the measuring values and the morphologic characteristics, and to make clear the logic of physicians' diagnosis. We think that the four basic morphologic characteristics of the discriminative diagnosis between benign and malignant nodules exist which are: (1) the density; (2) the homogeneity; (3) the definition; and (4) the convergence. To obtain each grade of the parameters, we developed an interpretation system. On the other hand, to obtain digital feature values, we used our computer aided diagnosis system. Interpretation experiments were performed by using 15 benign and 19 malignant cases of chest x-ray CT images. As the result of a statistical analysis, some digital features have the significant differences between benign and malignant nodules, and the morphological characteristics have also differences. Therefore the computerized system is feasible to help physicians' interpretation to distinct between malignant and benign nodules by showing digital feature values as some references.

  3. Factors functioning in nodule melanization of insects and their mechanisms of accumulation in nodules.

    PubMed

    Tokura, Ai; Fu, Gege Sun; Sakamoto, Maki; Endo, Haruka; Tanaka, Shiho; Kikuta, Shingo; Tabunoki, Hiroko; Sato, Ryoichi

    2014-01-01

    Nodules consisting of hemocytes and trapped microorganisms are important targets for melanization, which is best known in the insect immune system. We investigated factors functioning in nodule melanization and the mechanism by which these factors congregate in the nodule. BmHP21, BmSPH1 and BmSPH2, Bombyx mori orthologs of Manduca sexta serine protease HP21, serine protease homologs (SPH1 and SPH2), and a prophenoloxidase, BmPO1 were observed as inactive forms in the plasma, but as putatively active forms in the nodule. Production of prophenoloxidase-activating proteinases, BmPAP1 and BmPAP3/PPAE and BmPO1 were confirmed in hemocytes. BmSPH1 and BmSPH2 were observed on trapped bacterial cells in the nodule and were isolated from the surface of bacterial cells incubated with plasma. BmSPH1 and BmSPH2 were found in plasma in complex with a pattern recognition receptor, BmLBP. These data suggest that melanization-regulating factors congregate in nodules through a combination of microorganism-dependent and hemocyte-dependent routes. PMID:24262307

  4. Management of Pulmonary Nodules by Community Pulmonologists

    PubMed Central

    Aggarwal, Jyoti; Gould, Michael K.; Kearney, Paul; Diette, Gregory; Vachani, Anil; Fang, Kenneth C.; Silvestri, Gerard A.

    2015-01-01

    BACKGROUND: Pulmonary nodules (PNs) are a common reason for referral to pulmonologists. The majority of data for the evaluation and management of PNs is derived from studies performed in academic medical centers. Little is known about the prevalence and diagnosis of PNs, the use of diagnostic testing, or the management of PNs by community pulmonologists. METHODS: This multicenter observational record review evaluated 377 patients aged 40 to 89 years referred to 18 geographically diverse community pulmonary practices for intermediate PNs (8-20 mm). Study measures included the prevalence of malignancy, procedure/test use, and nodule pretest probability of malignancy as calculated by two previously validated models. The relationship between calculated pretest probability and management decisions was evaluated. RESULTS: The prevalence of malignancy was 25% (n = 94). Nearly one-half of the patients (46%, n = 175) had surveillance alone. Biopsy was performed on 125 patients (33.2%). A total of 77 patients (20.4%) underwent surgery, of whom 35% (n = 27) had benign disease. PET scan was used in 141 patients (37%). The false-positive rate for PET scan was 39% (95% CI, 27.1%-52.1%). Pretest probability of malignancy calculations showed that 9.5% (n = 36) were at a low risk, 79.6% (n = 300) were at a moderate risk, and 10.8% (n = 41) were at a high risk of malignancy. The rate of surgical resection was similar among the three groups (17%, 21%, 17%, respectively; P = .69). CONCLUSIONS: A substantial fraction of intermediate-sized nodules referred to pulmonologists ultimately prove to be lung cancer. Despite advances in imaging and nonsurgical biopsy techniques, invasive sampling of low-risk nodules and surgical resection of benign nodules remain common, suggesting a lack of adherence to guidelines for the management of PNs. PMID:26087071

  5. Fine needle aspiration cytology of epididymal nodules

    PubMed Central

    Shah, Vinaya B; Shet, Tanuja M; Lad, Shilpa K

    2011-01-01

    Background: The incidence of non neoplastic lesions are much more common in epididymis. Clinically, epididymal nodules are easily accessible to fine needle aspiration cytology (FNAC) procedure. There are very few literature reports documenting the role of cytology in evaluation of epididymal nodules. Thus, we studied patients presenting with palpable epididymis nodules in the out patient department (OPD) from a tertiary care general hospital. Aim: This study is aimed to put forth the diagnostic utility of FNAC in palpable lesions of epididymis. Materials and Methods: A total of 40 palpable epididymal nodules were aspirated as a routine OPD procedure as part of this study. Smears were fixed in isopropyl alcohol and air dried. In all the cases, wet fixed papanicoloau stained and air dried giemsa stained smears were studied. Zeihl Neelsen stain was performed in cases which yielded caseous aspirate. Results: Except for two cases of adenomatoid tumor of epididymis all other lesions were nonneoplastic and included 14 cases (35%) of tuberculous granulomatous inflammation, 10 (25%) cystic nodules (9 spermatoceles and 1 encysted hydrocele), 5 (12.5%) of nonspecific inflammations, 3 (7.5%) filarial infection, 3 (7.5%) sperm granulomas and 3 (7.5%) adenomatous hyperplasia of rete testes. Except for the two tumors, one adenomatous hyperplasia and one tuberculous lesion, no other lesion was excised. Follow up and response to therapy was available in 78% patients and resolution indicated appropriateness of the diagnosis Conclusions: Thus, as most of the lesions in epididymis are non neoplastic responding to medical line of treatment and FNAC served to aid diagnosis of non specific inflammation and avoid surgical excision in most cases. PMID:21897542

  6. Structural change and improvement of the mechanical properties of a lotus-type porous copper by wire-brushing

    NASA Astrophysics Data System (ADS)

    Lobos, J.; Suzuki, S.; Nakajima, H.; Ji, Y. S.; Fujii, H.; Terada, D.; Tsuji, N.

    2009-05-01

    The surface of lotus-type porous copper plates that had cylindrical open pores in the thickness direction (porosity 50.4%, average pore diameter 144.4 μm) were processed by wire-brushing. Open pores on the surface of the lotus copper are closed by a newly formed nonporous thin layer. Electron backscatter diffraction patterns of the processed plate cross section show that the deformed surface consists of ultra-fine grains and that a nonporous layer was formed on the deformation of the surface layer. The Vickers hardness of the wire-brushed lotus copper is higher than that of the wire-brushed non-porous copper. The Vickers hardness increases with the increase in the rate of revolution of the wire-brush due to grain refinement. The increment of the ultimate tensile strength of lotus copper by wire-brushing is larger than of non-porous copper. The increment of ultimate tensile strength of the lotus copper reaches maximum when the newly deformed layer closes all the pores on the surface. These results show that wire-brushing is an effective process for the improvement of mechanical properties for lotus metals.

  7. A rheumatoid nodule in an unusual location: mediastinal lymph node

    PubMed Central

    Yachoui, Ralph; Ward, Celine; Kreidy, Mazen

    2013-01-01

    Rheumatoid arthritis (RA) is a multisystem inflammatory disease characterised by destructive synovitis and varied extra-articular involvement. Rheumatoid lung nodules are the most common pulmonary manifestations of RA. Rheumatoid nodules in mediastinal lymph nodes are extremely uncommon. We describe a male patient with long-standing RA and subcutaneous rheumatoid nodules presenting with multiple lung nodules and mediastinal lymphadenopathies. Definite histopathology of a lymph node was consistent with necrobiotic granuloma due to RA. Clinicians should be aware of rheumatoid nodules as a potential cause of mediastinal lymphadenopathies, mainly in advanced rheumatoid arthritis. PMID:23645652

  8. Phenotypic and genetic characterization of rhizobia isolated from Hedysarum flexuosum in Northwest region of Morocco.

    PubMed

    Ezzakkioui, Fatima; El Mourabit, Nourdin; Chahboune, Rajaa; Castellano-Hinojosa, Antonio; Bedmar, Eulogio J; Barrijal, Said

    2015-07-01

    Seventy bacterial strains were isolated from root nodules of the legume Hedysarum flexuosum grown wild in soils from Northwest Morocco. Repetitive extragenic palindromic (REP)-polymerase chain reaction (PCR) clustered the strains into 30 REP-PCR groups. The nearly complete sequence of the 16S rRNA gene from a representative strain of each REP-PCR pattern showed that 17 strains were closely related to members of the genus Rhizobium of the family Rhizobiaceae of the Alphaproteobacteria. Pairwise alignments between globally aligned sequences of the 16S rRNA gene indicated that the strains from H. flexuosum had 99.75-100% identity with Rhizobium sullae type strain IS123(T). The phenotypic characteristics analyzed allowed description of a wide physiological diversity among the isolates, where the carbohydrate assimilation test was the most discriminating. Analysis of the 16S rRNA gene of a representative strains from the remaining 13 REP-PCR groups showed they belong to a wide variety of phylogenetic groups being closely related to species of genera Stenotrophomonas, Serratia, Massilia, Acinetobacter, Achromobacter, and Pseudomonas from the Beta- and Gammaproteobacteria. The R. sullae strains identified in this study produced effective symbiosis with their original host plant. None of the other bacterial strains could form nodules on H. flexuosum. PMID:25721451

  9. Diagnosis of liver nodules within and outside screening programs.

    PubMed

    Colombo, Massimo

    2015-01-01

    Evaluation of a liver nodule detected with ultrasound includes the recovery of a detailed medical history, a physical exam, appropriate contrast imaging examinations and, in selected cases, histopathology. In this setting, identification of liver disease accompanying a liver nodule helps distinction between benign nodules and metastatic malignant nodules from primary liver cancer, as recommended by scientific liver societies. Diagnostic algorithms for a liver nodule in patients with liver disease involve contrast CT scan, magnetic resonance imaging or contrast enhanced ultrasounds to show the typical neoplastic pattern of early arterial hyperenhancement wash-in followed by hypoenhancement in the late portal phase wash out. The flow charts developed by western societies utilize the discriminant criterion of tumor size i.e. the radiological diagnosis being endorsed in a nodule equal or greater than 1 cm whereas eastern societies rely on the recognition of a typical vascular pattern of the node, independently of size. Differential diagnosis should be obtained to differentiate liver related nodules like regenerative macronodules (more than 20% of the cases) and the less frequent intrahepatic cholangiocarcinoma (~2% of the cases) from liver disease unrelated nodules like hemangioma (~4%), neuroendocrine metastatic nodules (~1%) and focal nodular hyperplasia. In patients without liver disease, the most common liver nodules in the liver are hemangioma (~1.5%), focal nodular hyperplasia (0.03%) and hepatocellular adenoma (up to 0.004% in long term users of oral contraceptives). Optimization of management of patients with a liver nodule requires establishment of a multidisciplinary clinic. PMID:25864209

  10. Dual Genetic Pathways Controlling Nodule Number in Medicago truncatula1

    PubMed Central

    Penmetsa, R. Varma; Frugoli, Julia A.; Smith, Lucinda S.; Long, Sharon R.; Cook, Douglas R.

    2003-01-01

    We report the isolation and characterization of a new Medicago truncatula hyper-nodulation mutant, designated sunn (super numeric nodules). Similar to the previously described ethylene-insensitive mutant sickle, sunn exhibits a 10-fold increase in the number of nodules within the primary nodulation zone. Despite this general similarity, these two mutants are readily distinguished based on anatomical, genetic, physiological, and molecular criteria. In contrast to sickle, where insensitivity to ethylene is thought to be causal to the hyper-nodulation phenotype (R.V. Penmetsa, D.R. Cook [1997] Science 275: 527–530), nodulation in sunn is normally sensitive to ethylene. Nevertheless, sunn exhibits seedling root growth that is insensitive to ethylene, although other aspects of the ethylene triple response are normal; these observations suggest that hormonal responses might condition the sunn phenotype in a manner distinct from sickle. The two mutants also differ in the anatomy of the nodulation zone: Successful infection and nodule development in sunn occur predominantly opposite xylem poles, similar to wild type. In sickle, however, both infection and nodulation occur randomly throughout the circumference of the developing root. Genetic analysis indicates that sunn and sickle correspond to separate and unlinked loci, whereas the sunn/skl double mutant exhibits a novel and additive super-nodulation phenotype. Taken together, these results suggest a working hypothesis wherein sunn and sickle define distinct genetic pathways, with skl regulating the number and distribution of successful infection events, and sunn regulating nodule organogenesis. PMID:12644652

  11. CARDIO--a Lotus 1-2-3 based computer program for rapid calculation of cardiac output from dye or thermal dilution curves.

    PubMed

    Brill, R W; Bushnell, P G

    1989-01-01

    We have developed a menu-driven computer program (CARDIO), based on a Lotus 1-2-3 template and a series of macrocommands, that rapidly and semiautomatically calculates cardiac output from dye or thermal dilution curves. CARDIO works with any dye or thermal dilution recorder with an analog output, any analog to digital (A-to-D) conversion system, and any computer capable of running Lotus 1-2-3 version 2. No prior experience with Lotus 1-2-3 is needed to operate CARDIO, but experienced users can take full advantage of Lotus 1-2-3's graphics, data manipulation, and data retrieval capabilities. PMID:2689079

  12. Tissue Cultures Derived from Ineffective Root Nodules of Alfalfa 1

    PubMed Central

    Vance, Carroll P.; Johnson, Lois E. B.; Boylan, Kristin L. M.

    1984-01-01

    Callus tissue cultures were developed from apical meristem regions of tumor-like ineffective root nodules of alfalfa. Callus growth was a function of tissue source and hormone composition and concentration. Callus derived from ineffective nodules also were shown not to contain Rhizobium meliloti. Glutamate dehydrogenase, glutamine synthetase, glutamate synthase, glutamate oxaloacetate transaminase and phosphoenolpyruvate carboxylase activities were present in callus cultures and in the respective nodule source used for callus induction. The mean specific activity of all enzymes evaluated was higher in callus cultures than in ineffective nodules. Quantitative but not qualitative differences in enzyme activities were evident between ineffective nodules and callus derived from these nodules. Tissue cultures derived from ineffective nodules may provide a model system to evaluate host plant-Rhizobium interactions. Images Fig. 1 PMID:16663985

  13. Interfacing COTS Speech Recognition and Synthesis Software to a Lotus Notes Military Command and Control Database

    NASA Astrophysics Data System (ADS)

    Carr, Oliver

    2002-10-01

    Speech recognition and synthesis technologies have become commercially viable over recent years. Two current market leading products in speech recognition technology are Dragon NaturallySpeaking and IBM ViaVoice. This report describes the development of speech user interfaces incorporating these products with Lotus Notes and Java applications. These interfaces enable data entry using speech recognition and allow warnings and instructions to be issued via speech synthesis. The development of a military vocabulary to improve user interaction is discussed. The report also describes an evaluation in terms of speed of the various speech user interfaces developed using Dragon NaturallySpeaking and IBM ViaVoice with a Lotus Notes Command and Control Support System Log database.

  14. Biomimetic superhydrophobic surfaces by combining mussel-inspired adhesion with lotus-inspired coating.

    PubMed

    Xue, Chao-Hua; Ji, Xue-Qing; Zhang, Jing; Ma, Jian-Zhong; Jia, Shun-Tian

    2015-08-21

    Superhydrophobic surfaces on PET textiles were fabricated by combined bioinspiration from the strong adhesion of marine mussels and the two-scale structure of lotus leaves under mild conditions. Dopamine can spontaneously polymerize in alkaline aqueous solution to form a thin adhesive layer of polydopamine (PDA) wrapping on the micro-scale fibers. The as-formed thin PDA layer worked as a reactive template to generate PDA nanoparticles decorated on the fiber surfaces, imparting the textiles with excellent UV-shielding properties as well as a hierarchical structure similar to the morphology of the lotus leaf. After further modification with perfluorodecyl trichlorosilane, the textiles turned superhydrophobic with a water contact angle higher than 150°. Due to the strong adhesion of PDA to a wide range of materials, the present strategy may be extendable to fabrication of superhydrophobic surfaces on a variety of other substrates. PMID:26222622

  15. Identification and antioxidant properties of polyphenols in lotus seed epicarp at different ripening stages.

    PubMed

    Liu, Ying; Ma, Shuang-shuang; Ibrahim, S A; Li, Er-hu; Yang, Hong; Huang, Wen

    2015-10-15

    In this study, polyphenols from lotus seed epicarp (PLSE) at three different ripening stages were purified by column chromatography and identified by RP-HPLC and HPLC-ESI-MS(2). The antioxidant activities of PLSE were also investigated. We found that the contents of PLSE at the green ripening stage, half ripening stage and full ripening stage are 13.08%, 10.95% and 6.73% respectively. The levels of catechin, epicatechin, hyperoside, and isoquercitrin in PLSE at the three different ripening stages were different. Moreover, the amounts of catechin and epicatechin decreased, while the contents of hyperoside and isoquercitrin increased as the seed ripened. We found that PLSE at three different ripening stages had good scavenging abilities on DPPH and ABTS(+) radicals. However, the scavenging ability decreased with maturation. Our results may be valuable with regard to the utilization of lotus seed epicarp as a functional food material. PMID:25952854

  16. Fabrication of lotus-type porous copper through thermal decomposition of titanium hydride

    NASA Astrophysics Data System (ADS)

    Ide, T.; Nakajima, H.

    2009-05-01

    Lotus-type porous copper was fabricated by unidirectional solidification through thermal decomposition of titanium hydride. Effects of additive method and additive amount of titanium hydride on pore formation were investigated. The porosity of lotus copper depends on additive method and additive amount of titanium hydride. The pore formation effectively occurs in the method that titanium hydride decomposes in molten copper. For all the additive methods of titanium hydride, the porosity increases and pore diameter does not change with increasing additive amount of titanium hydride. While, for adding large amount of titanium hydride, the porosity became constant. This is because hydrogen solubility in liquid phase does not change owing to bubbling of hydrogen gas.

  17. Tritium assay of Li/sub 2/O in the LBM/LOTUS experiments

    SciTech Connect

    Quanci, J.; Azam, S.; Bertone, P.

    1986-11-01

    The Lithium Blanket Module (LBM) is an assembly of over 20,000 cylindrical lithium oxide pellets in an array representative of a limited-coverage breeding zone for a toroidal fusion device. A principal objective of the LBM program is to test the ability of advanced neutronics coding to model the tritium breeding characteristics of a fusion device blanket. The LBM has been irradiated at the Ecole Polytechnique Federale de Lausanne (EPFL) LOTUS facility with a 14 MeV point-neutron source. Princeton Plasma Physics Laboratory (PPPL) and EPFL assayed the tritium bred in lithium oxide diagnostic samples placed at various positions in the LBM. PPPL employed a thermal extraction technique while EPFL used a dissolution method. The results for the assay are reported and compared to MCNP Monte Carlo neutronics calculations for the LBM/LOTUS system.

  18. Biomimetic superhydrophobic surfaces by combining mussel-inspired adhesion with lotus-inspired coating

    NASA Astrophysics Data System (ADS)

    Xue, Chao-Hua; Ji, Xue-Qing; Zhang, Jing; Ma, Jian-Zhong; Jia, Shun-Tian

    2015-08-01

    Superhydrophobic surfaces on PET textiles were fabricated by combined bioinspiration from the strong adhesion of marine mussels and the two-scale structure of lotus leaves under mild conditions. Dopamine can spontaneously polymerize in alkaline aqueous solution to form a thin adhesive layer of polydopamine (PDA) wrapping on the micro-scale fibers. The as-formed thin PDA layer worked as a reactive template to generate PDA nanoparticles decorated on the fiber surfaces, imparting the textiles with excellent UV-shielding properties as well as a hierarchical structure similar to the morphology of the lotus leaf. After further modification with perfluorodecyl trichlorosilane, the textiles turned superhydrophobic with a water contact angle higher than 150°. Due to the strong adhesion of PDA to a wide range of materials, the present strategy may be extendable to fabrication of superhydrophobic surfaces on a variety of other substrates.

  19. Combined topical application of lotus and green tea improves facial skin surface parameters.

    PubMed

    Mahmood, Tariq; Akhtar, Naveed

    2013-04-01

    No study has yet determined the anti-wrinkle efficacy of green tea plus lotus in Asian subjects using skin image analysis technique. In this study, the efficacy of two cosmetic active formulations intended for the treatment of facial wrinkles (green tea and lotus extract) has been evaluated in healthy subjects using a non-invasive device, the Visioscan(®) VC, and software for surface evaluation of living skin (SELS). Thirty-three healthy Asian subjects, all men, were enrolled after consent in a placebo-controlled comparative study with a split face design. One group applied multiple emulsions with green tea. The second group applied multiple emulsions with lotus extract, while a third group applied a multiple emulsion with a combination of both extracts. In all three groups, active formulations were applied to one side of the face and the placebo to the other side, once daily over the 60-day treatment course. Non-invasive measurements were performed at baseline and on days 30 and 60. Interesting and significant improvements were observed for the treatment effects on skin roughness (SEr), scaliness (SEsc), smoothness (SEsm), and wrinkling (SEw). For example, a 49.99% improvement in skin smoothness (SEsm) from baseline value and -23.22% and perfection in facial wrinkles (SEw) substantiated that combined treatment is superior over single treatments. Green tea and lotus combined in multiple emulsions brought a superior synergistic anti-aging effect. We conclude that diverse anti-oxidant constituents in both plants have a potential influence on skin surface parameters, thus indicating these plants as the future of new anti-aging products. PMID:23267660

  20. Effect of strain rate on the compressive deformation behaviors of lotus-type porous copper

    NASA Astrophysics Data System (ADS)

    Liu, Xin-hua; Huang, Hai-you; Xie, Jian-xin

    2014-07-01

    Lotus-type porous copper was fabricated by unidirectional solidification, and compressive experiments were subsequently conducted in the strain rate range of 10-3-2400 s-1 with the compressive direction parallel to the pores. A GLEEBLE-1500 thermal-mechanical simulation system and a split Hopkinson pressure bar (SHPB) were used to investigate the effect of strain rate on the compressive deformation behaviors of lotus-type porous copper. The influence mechanism of strain rate was also analyzed by the strain-controlling method and by high-speed photography. The results indicated that the stress-strain curves of lotus-typed porous copper consist of a linear elastic stage, a plateau stage, and a densification stage at various strain rates. At low strain rate (< 1.0 s-1), the strain rate had little influence on the stress-strain curves; but when the strain rate exceeded 1.0 s-1, it was observed to strongly affect the plateau stage, showing obvious strain-rate-hardening characteristics. Strain rate also influenced the densification initial strain. The densification initial strain at high strain rate was less than that at low strain rate. No visible inhomogeneous deformation caused by shockwaves was observed in lotus-type porous copper during high-strain-rate deformation. However, at high strain rate, the bending deformation characteristics of the pore walls obviously differed from those at low strain rate, which was the main mechanism by which the plateau stress exhibited strain-rate sensitivity when the strain rate exceeded a certain value and exhibited less densification initial strain at high strain rate.

  1. Effects of potato and lotus leaf extract intake on body composition and blood lipid concentration

    PubMed Central

    Lee, Keuneil; Kim, Jongkyu; Lee, Namju; Park, Sok; Cho, Hyunchul; Chun, Yoonseok

    2015-01-01

    [Purpose] The purpose of this study was to investigate the effects of potato and lotus leaf extract intake on body composition, abdominal fat, and blood lipid concentration in female university students. [Methods] A total of 19 female university students participated in this 8-week study, and they were randomly assigned into 2 groups; potato and lotus leaf extract (skinny-line) administered group (SKG, n =9) and placebo group (PG, n = 10). The main results of the present study are presented below. [Results] 1) Body mass index, and percent body fat and abdominal fat in students of the SKG showed a decreasing tendency without significant interaction, 2) total cholesterol (TC), triglyceride (TG), and low density lipoprotein (LDL-C) in students of the SKG showed an averagely decreasing tendency and there was a significant interaction of TC only, 3) high density lipoprotein (HDL-C) in students of the SKG showed an increasing tendency without significant interaction, and 4) Z-score of fatness testing interaction in group × repetition did not show a significant interaction; however, there was a significant interaction of TC in group × repetition. Based on these results, 8-week intake of potato and lotus leaf extract had a positive effect of lowering TC. On the other hand, it had no significant effect on other types of lipids and percent body fat changes. [Conclusion] There was a positive tendency of blood lipids in students of the SKG and it seems that potato and lotus leaf extract intake might prevent obesity and improve obesity related syndromes. PMID:25960952

  2. Isolation and antiproliferative activity of Lotus corniculatus lectin towards human tumour cell lines.

    PubMed

    Rafiq, Shaista; Majeed, Rabiya; Qazi, Asif Khurshid; Ganai, Bashir Ahmad; Wani, Ishfak; Rakhshanda, Syed; Qurishi, Yasrib; Sharma, P R; Hamid, Abid; Masood, Akbar; Hamid, Rabia

    2013-12-15

    The objective of the study was to investigate the anti cancer activity of a lectin isolated from Lotus corniculatus seeds. A tetrameric 70kDa galactose specific lectin was purified using two step simple purification protocol which involved affinity chromatography on AF-BlueHC650M and gel filtration on Sephadex G-100. The lectin was adsorbed on AF-BlueHC650M and desorbed using 1M NaCl in the starting buffer. Gel filtration on Sephadex G-100 yielded a major peak absorbance that gave two bands of 15kDa and 20kDa in SDS PAGE. Hemagglutination activity was completely preserved, when the temperature was in the range of 20-60°C. However, drastic reduction in activity occurred at temperatures above 60°C. Full hemagglutination activity was retained at ambient pH 4-12. Thereafter no activity was observed above pH 13. Hemaglutination of the lectin was inhibited by d-galactose. The lectin showed a strong antiproliferative activity towards human leukemic (THP-1) cancer cells followed by lung cancer (HOP62) cells and HCT116 with an IC50 of 39μg/ml and 50μg/ml and 60μg/ml respectively. Flow cytometry analysis showed an increase in the percentage of cells in sub G0G1 phase confirming that Lotus corniculatus lectin induced apoptosis. Morphological observations showed that Lotus corniculatus lectin (LCL) treated THP-1 cells displayed apparent apoptosis characteristics such as nuclear fragmentation, appearance of membrane enclosed apoptotic bodies and DNA fragmentation. Lotus corniculatus lectin (LCL) effectively inhibits the cell migration in a dose dependent manner as indicated by the wound healing assay. PMID:24055517

  3. Desert Research and Technology Studies Exposure of Lotus Coated Electrodynamic Shield Samples

    NASA Technical Reports Server (NTRS)

    Rodriquez, Marcello; Peters, Wanda C.; Straka, Sharon A.; Jones, Craig B.

    2011-01-01

    The Lotus dust mitigation coating and the electrodynamic shield (EDS) are two new technologies currently being developed by NASA as countermeasures for addressing dust accumulation for long-duration human space exploration. These combined technologies were chosen by the Habitation Demonstration Unit (HDU) program for desert dust exposure at the Desert Research and Technologies Studies (D-RaTS) test site in Arizona. Characterization of these samples was performed prior to, during and post D-RaTS exposure.

  4. Predicting Malignancy in Thyroid Nodules: Molecular Advances

    PubMed Central

    Melck, Adrienne L.; Yip, Linwah

    2016-01-01

    Over the last several years, a clearer understanding of the genetic alterations underlying thyroid carcinogenesis has developed. This knowledge can be utilized to tackle one of the greatest challenges facing thyroidologists: management of the indeterminate thyroid nodule. Despite the accuracy of fine needle aspiration cytology, many patients undergo invasive surgery in order to determine if a follicular or Hurthle cell neoplasm is malignant, and better diagnostic tools are required. A number of biomarkers have recently been studied and show promise in this setting. In particular, BRAF, RAS, PAX8-PPARγ, microRNAs and loss of heterozygosity have each been demonstrated as useful molecular tools for predicting malignancy and can thereby guide decisions regarding surgical management of nodular thyroid disease. This review summarizes the current literature surrounding each of these markers and highlights our institution’s prospective analysis of these markers and their subsequent incorporation into our management algorithms for thyroid nodules. PMID:21818817

  5. Isolated Rheumatoid Nodules: A Diagnostic Dilemma

    PubMed Central

    Gale, Michael; Gilbert, Erin; Blumenthal, David

    2015-01-01

    We present a 27-year-old male with multiple nonpainful soft tissue masses over several metacarpals, bilateral elbows, the left wrist, and both knees since the age of 4. Physical exam was significant for firm, nonmobile, nodular growths over the extensor surfaces of bilateral elbows and knees and on the 2nd and 5th metacarpal phalangeal joints. Laboratory studies revealed an unremarkable rheumatoid factor, negative ANA screening and normal joint radiographs. Differential diagnosis included subcutaneous granuloma annulare (SGA), seronegative rheumatoid nodule, and calcinosis cutis. Biopsy is the only method to distinguish benign rheumatoid nodules from SGA. This case illustrates the importance of biopsy in diagnosis, an awareness of the potential complications, and the need for good follow-up. PMID:25802526

  6. Detection of pulmonary nodule growth with dose reduced chest tomosynthesis: a human observer study using simulated nodules

    NASA Astrophysics Data System (ADS)

    Söderman, Christina; Johnsson, Ã. se; Vikgren, Jenny; Rossi Norrlund, Rauni; Molnar, David; Mirzai, Maral; Svalkvist, Angelica; Mânsson, Lars Gunnar; Bâth, Magnus

    2016-03-01

    Chest tomosynthesis may be a suitable alternative to computed tomography for the clinical task of follow up of pulmonary nodules. The aim of the present study was to investigate the detection of pulmonary nodule growth suggestive of malignancy using chest tomosynthesis. Previous studies have indicated remained levels of detection of pulmonary nodules at dose levels corresponding to that of a conventional lateral radiograph, approximately 0.04 mSv, which motivated to perform the present study this dose level. Pairs of chest tomosynthesis image sets, where the image sets in each pair were acquired of the same patient at two separate occasions, were included in the study. Simulated nodules with original diameters of approximately 8 mm were inserted in the pairs of image sets, simulating situations where the nodule had remained stable in size or increased isotropically in size between the two different imaging occasions. Four different categories of nodule growth were included, corresponding to a volume increase of approximately 21 %, 68 %, 108 % and 250 %. All nodules were centered in the depth direction in the tomosynthesis images. All images were subjected to a simulated dose reduction, resulting in images corresponding to an effective dose of 0.04 mSv. Four observers were given the task of rating their confidence that the nodule was stable in size or not on a five-level rating scale. This was done both before any size measurements were made of the nodule as well as after measurements were performed. Using Receiver operating characteristic analysis, the rating data for the nodules that were stable in size was compared to the rating data for the nodules simulated to have increased in size. Statistically significant differences between the rating distributions for the stable nodules and all of the four nodule growth categories were found. For the three largest nodule growths, nearly perfect detection of nodule growth was seen. In conclusion, the present study

  7. Self-propulsion of dew drops on lotus leaves: a potential mechanism for self cleaning.

    PubMed

    Watson, Gregory S; Gellender, Marty; Watson, Jolanta A

    2014-01-01

    This study shows that condensation on the hierarchically structured lotus leaf can facilitate self-propulsion of water droplets off the surface. Droplets on leaves inclined at high angles can be completely removed from the surface by self-propulsion with the assistance of gravity. Due to the small size of mobile droplets, light breezes may also fully remove the propelled droplets, which are typically projected beyond the boundary layer of the leaf cuticle. Moreover the self-propelled droplets/condensate were able to remove contaminants (eg silica particles) from the leaf surface. The biological significance of this process may be associated with maintaining a healthy cuticle surface when the action of rain to clean the surface via the lotus effect is not possible (due to no precipitation). Indeed, the native lotus plants in this study were located in a region with extended time periods (several months) without rain. Thus, dew formation on the leaf may provide an alternative self-cleaning mechanism during times of drought and optimise the functional efficiency of the leaf surface as well as protecting the surface from long term exposure to pathogens such as bacteria and fungi. PMID:24628521

  8. Not all the infected develop the disease - A "Lotus and Cactus" model.

    PubMed

    Pitchappan, Ramasamy M

    2016-06-01

    The immunogenetic dictum "not all the infected develop the disease" can best be explained by a "Lotus and Cactus" model. Lotuses grow in ponds and cacti in deserts: analogously, we can say that tubercle patient's lung (genetic makeup) functions as an ideal 'broth' for Mycobacterium tuberculosis (M.tb) germs to grow, but not the lungs of an endemic control. HLA association studies from Europe to Asia since 1983 till date, have shown a persistent HLA DR2 (15) association. Further, HLA DR2 and non-DR2 endemic controls showed disparate patterns of immune responses and gene expressions. The host and pathogen MHC diversities, Th1-Th2 paradigm and cytokine circuits all may play a crucial role in TB susceptibility. It is possible to decipher the protective immunity by controlling the known confounders - epidemiological, demographic, socio-biological and also host and pathogen diversities. This has become significant with our understanding on the 'out of Africa' migration and neolithic co-dispersal of M.tb with modern human. Divergence and expansion of various MHCs (eg HLA-DRB1*15, HLA-B*57) and non-MHC alleles in various continents might be responsible for the skewed transmission and distribution of the infectious diseases around the globe. The 'Lotus and Cactus' model proposed here exemplifies this. A holistic genetic epidemiology approach employing modern tools is the need of the hour to better understand infectious disease susceptibility. PMID:26611827

  9. Gene Expression Profile in the Long-Living Lotus: Insights into the Heat Stress Response Mechanism

    PubMed Central

    Li, Naiwei; Chang, Yajun; Yao, Dongrui

    2016-01-01

    Lotus (Nelumbo Adans) is an aquatic perennial plant that flourished during the middle Albian stage. In this study, we characterized the digital gene expression signatures for China Antique lotus under conditions of heat shock stress. Using RNA-seq technology, we sequenced four libraries, specifically, two biological replicates for control plant samples and two for heat stress samples. As a result, 6,528,866 to 8,771,183 clean reads were mapped to the reference genome, accounting for 92–96% total clean reads. A total of 396 significantly altered genes were detected across the genome, among which 315 were upregulated and 81 were downregulated by heat shock stress. Gene ontology (GO) enrichment of differentially expressed genes revealed protein folding, cell morphogenesis and cellular component morphogenesis as the top three functional terms under heat shock stress. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis led to the identification of protein processing in endoplasmic reticulum, plant-pathogen interactions, spliceosome, endocytosis, and protein export as significantly enriched pathways. Among the upregulated genes, small heat shock proteins (sHsps) and genes related to cell morphogenesis were particularly abundant under heat stress. Data from the current study provide valuable clues that may help elucidate the molecular events underlying heat stress response in China Antique lotus. PMID:27018792

  10. A biomimetic nano hybrid coating based on the lotus effect and its anti-biofouling behaviors

    NASA Astrophysics Data System (ADS)

    Li, Jiang; Wang, Guoqing; Meng, Qinghua; Ding, Chunhua; Jiang, Hong; Fang, Yongzeng

    2014-10-01

    To develop an environmentally friendly anti-biofouling coating in virtue of bionics, a block copolymer containing fluorine (Coplm_F) of low surface energy was prepared by copolymerization. The Ag-loaded mesoporous silica (Ag@SBA) acting as a controlled-release antifoulant was prepared from the mesoporous silica (SBA-15). The nano hybrid coating (Ag@SBA/Coplm_F) composing of the Coplm_F and Ag@SBA was to biomimetically simulate the lotus microstructure. The concentration of fluorine element on surface was analyzed by the energy dispersive spectroscopy (EDS) and found rising to 1.45% after hybridation, which could be explained by the driving effect of SBA-15 via the hydrogen bond. This nanoscale morphology of the hybrid coating was measured and found highly semblable to the microstructure of the lotus surface. The contact angle was determined as 151° which confirmed the superhydrophobicity and lotus effect. The adhesion behaviors of Pseudomonas fluorescens, Diatoms, and Chlorella on the surface of the nano hybrid coating (Ag@SBA/Coplm_F) were studied and good effects of anti-biofouling were observed.

  11. Evolution of NIN-like proteins in Arabidopsis, rice, and Lotus japonicus.

    PubMed

    Schauser, Leif; Wieloch, Wioletta; Stougaard, Jens

    2005-02-01

    Genetic studies in Lotus japonicus and pea have identified Nin as a core symbiotic gene required for establishing symbiosis between legumes and nitrogen fixing bacteria collectively called Rhizobium. Sequencing of additional Lotus cDNAs combined with analysis of genome sequences from Arabidopsis and rice reveals that Nin homologues in all three species constitute small gene families. In total, the Arabidopsis and rice genomes encode nine and three NIN-like proteins (NLPs), respectively. We present here a bioinformatics analysis and prediction of NLP evolution. On a genome scale we show that in Arabidopsis, this family has evolved through segmental duplication rather than through tandem amplification. Alignment of all predicted NLP protein sequences shows a composition with six conserved modules. In addition, Lotus and pea NLPs contain segments that might characterize NIN proteins of legumes and be of importance for their function in symbiosis. The most conserved region in NLPs, the RWP-RK domain, has secondary structure predictions consistent with DNA binding properties. This motif is shared by several other small proteins in both Arabidopsis and rice. In rice, the RWP-RK domain sequences have diversified significantly more than in Arabidopsis. Database searches reveal that, apart from its presence in Arabidopsis and rice, the motif is also found in the algae Chlamydomonas and in the slime mold Dictyostelium discoideum. Thus, the origin of this putative DNA binding region seems to predate the fungus-plant divide. PMID:15785851

  12. Energy related investment decision analyses for railroads using LOTUS 1-2-3

    SciTech Connect

    Clipp, F.P.; Law, E.H.

    1987-01-01

    This paper presents the results of a project funded by the South Carolina Energy Research and Development Center (SCERDC). The SCERDC wanted to encourage the consideration of energy efficiency in railway management decisions. To facilitate this, a LOTUS 1-2-3 based program called CRIDA (Clemson Rail Investment Decision Analysis) was developed. CRIDA builds on the results of a completed project that yields information on energy consumption of railway vehicles using LOTUS 1-2-3. The project resulted in a LOTUS 1-2-3 based program called CRCEP (Clemson Rail Car Energy Program). CRCEP permits the estimation of energy usage of rail cars due to grades, aerodynamic losses, and energy lost across the wheel-rail interfaces during curving and negotiation of randomly irregular track. CRCEP is both route and car specific. The work reported in this paper expands the usefulness of that already reported by applying investment decision analysis tools that enable us to translate the energy consumption output into language understandable and usable by management decision makers. The tools implemented in CRIDA are not specific to use with CRCEP. Any analysis model or data from real trials can be input to CRIDA for analysis.

  13. LOTUS - Preparing Sentinel-3 SAR Altimetry Processing for Ocean and Land.

    NASA Astrophysics Data System (ADS)

    Knudsen, Per; Andersen, Ole; Nielsen, Karina; Stenseng, Lars; Villadsen, Heidi; Pelloquin, Camille; Reppucci, Antonio; Berry, Philippa; Thibaut, Pierre; Moreau, Thomas; Bauer-Gottwein, Peter; Schneider, Raphael; Madsen, Henrik; Petersen, Ole; Grode, Patrick

    2016-04-01

    The Sentinel-3 satellite mission with its SRAL instrumentation contains new features compared to the conventional radar altimeter mission that form the basis for new innovative scientific analyses of both ocean and inland water levels. To utilize the full potential of the new data source, new methods and processing chains need to be developed. Subsequently, new potential Copernicus products should be developed that utilize the improved along-track resolution over both the oceans and over land. The main objective of the LOTUS project is to prepare the scientific and operational use of data from Sentinels 3. Then new operational processing, validation and delivery mechanisms need to be developed and implemented for generating the new dynamic products. Finally, the take-up of the new Copernicus products by the value-adding sectors needs to be stimulated and demonstrated to ensure that they will be used for commercial activities. LOTUS will develop processing scheme for extracting high-resolution sea surface heights, wave heights and wind speeds from SAR mode data. Over land, the LOTUS will develop processing scheme for extracting high-resolution river and lake heights, soil moisture, and snow water equivalents. This presentation shows results based on analyses using CRYOSAT data and available S-3 data. Furthermore, new DEMO data sets are presented and examples of scientific impact demonstrated.

  14. LOTUS - Preparing Sentinel-3 SAR Altimetry Processing for Ocean and Land

    NASA Astrophysics Data System (ADS)

    Knudsen, P.; Nielsen, K.; Andersen, O. B.

    2015-12-01

    The Sentinel-3 satellite mission with its SRAL instrumentation contains new features compared to the conventional radar altimeter mission that form the basis for new innovative scientific analyses of both ocean and inland water levels. To utilize the full potential of the new data source, new methods and processing chains need to be developed. Subsequently, new potential Copernicus products should be developed that utilize the improved along-track resolution over both the oceans and over land. The main objective of the LOTUS project is to prepare the scientific and operational use of data from Sentinels 3. Then new operational processing, validation and delivery mechanisms need to be developed and implemented for generating the new dynamic products. Finally, the take-up of the new Copernicus products by the value-adding sectors needs to be stimulated and demonstrated to ensure that they will be used for commercial activities. LOTUS will develop processing scheme for extracting high-resolution sea surface heights, wave heights and wind speeds from SAR mode data. Over land, the LOTUS will develop processing scheme for extracting high-resolution river and lake heights, soil moisture, and snow water equivalents. This presentation shows results based on analyses using CryoSat.2 data and available Sentinel-3 data. Furthermore, new DEMO data sets are presented and examples of scientific impact demonstrated.

  15. Transcriptomic Analysis of the Regulation of Rhizome Formation in Temperate and Tropical Lotus (Nelumbo nucifera).

    PubMed

    Yang, Mei; Zhu, Lingping; Pan, Cheng; Xu, Liming; Liu, Yanling; Ke, Weidong; Yang, Pingfang

    2015-01-01

    Rhizome is the storage organ of lotus derived from modified stems. The development of rhizome is a complex process and depends on the balanced expression of the genes that is controlled by environmental and endogenous factors. However, little is known about the mechanism that regulates rhizome girth enlargement. In this study, using RNA-seq, transcriptomic analyses were performed at three rhizome developmental stages-the stolon, middle swelling and later swelling stage -in the cultivars 'ZO' (temperate lotus with enlarged rhizome) and 'RL' (tropical lotus with stolon). About 348 million high-quality reads were generated, and 88.5% of the data were mapped to the reference genome. Of 26783 genes identified, 24069 genes were previously predicted in the reference, and 2714 genes were novel transcripts. Moreover, 8821 genes were differentially expressed between the cultivars at the three stages. Functional analysis identified that these genes were significantly enriched in pathways carbohydrate metabolism and plant hormone signal transduction. Twenty-two genes involved in photoperiod pathway, starch metabolism and hormone signal transduction were candidate genes inducing rhizome girth enlargement. Comparative transcriptomic analysis detected several differentially expressed genes and potential candidate genes required for rhizome girth enlargement, which lay a foundation for future studies on molecular mechanisms underlying rhizome formation. PMID:26279185

  16. Transcriptomic Analysis of the Regulation of Rhizome Formation in Temperate and Tropical Lotus (Nelumbo nucifera)

    PubMed Central

    Yang, Mei; Zhu, Lingping; Pan, Cheng; Xu, Liming; Liu, Yanling; Ke, Weidong; Yang, Pingfang

    2015-01-01

    Rhizome is the storage organ of lotus derived from modified stems. The development of rhizome is a complex process and depends on the balanced expression of the genes that is controlled by environmental and endogenous factors. However, little is known about the mechanism that regulates rhizome girth enlargement. In this study, using RNA-seq, transcriptomic analyses were performed at three rhizome developmental stages—the stolon, middle swelling and later swelling stage —in the cultivars ‘ZO’ (temperate lotus with enlarged rhizome) and ‘RL’ (tropical lotus with stolon). About 348 million high-quality reads were generated, and 88.5% of the data were mapped to the reference genome. Of 26783 genes identified, 24069 genes were previously predicted in the reference, and 2714 genes were novel transcripts. Moreover, 8821 genes were differentially expressed between the cultivars at the three stages. Functional analysis identified that these genes were significantly enriched in pathways carbohydrate metabolism and plant hormone signal transduction. Twenty-two genes involved in photoperiod pathway, starch metabolism and hormone signal transduction were candidate genes inducing rhizome girth enlargement. Comparative transcriptomic analysis detected several differentially expressed genes and potential candidate genes required for rhizome girth enlargement, which lay a foundation for future studies on molecular mechanisms underlying rhizome formation. PMID:26279185

  17. Gene Expression Profile in the Long-Living Lotus: Insights into the Heat Stress Response Mechanism.

    PubMed

    Liu, Xiaojing; Du, Fengfeng; Li, Naiwei; Chang, Yajun; Yao, Dongrui

    2016-01-01

    Lotus (Nelumbo Adans) is an aquatic perennial plant that flourished during the middle Albian stage. In this study, we characterized the digital gene expression signatures for China Antique lotus under conditions of heat shock stress. Using RNA-seq technology, we sequenced four libraries, specifically, two biological replicates for control plant samples and two for heat stress samples. As a result, 6,528,866 to 8,771,183 clean reads were mapped to the reference genome, accounting for 92-96% total clean reads. A total of 396 significantly altered genes were detected across the genome, among which 315 were upregulated and 81 were downregulated by heat shock stress. Gene ontology (GO) enrichment of differentially expressed genes revealed protein folding, cell morphogenesis and cellular component morphogenesis as the top three functional terms under heat shock stress. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis led to the identification of protein processing in endoplasmic reticulum, plant-pathogen interactions, spliceosome, endocytosis, and protein export as significantly enriched pathways. Among the upregulated genes, small heat shock proteins (sHsps) and genes related to cell morphogenesis were particularly abundant under heat stress. Data from the current study provide valuable clues that may help elucidate the molecular events underlying heat stress response in China Antique lotus. PMID:27018792

  18. Biogenesis of C-Glycosyl Flavones and Profiling of Flavonoid Glycosides in Lotus (Nelumbo nucifera)

    PubMed Central

    Li, Shan-Shan; Wu, Jie; Chen, Li-Guang; Du, Hui; Xu, Yan-Jun; Wang, Li-Jing; Zhang, Hui-Jin; Zheng, Xu-Chen; Wang, Liang-Sheng

    2014-01-01

    Flavonoids in nine tissues of Nelumbo nucifera Gaertner were identified and quantified by high-performance liquid chromatography with diode array detector (HPLC-DAD) and HPLC-electrospray ionization-mass spectrometry (HPLC-ESI-MSn). Thirty-eight flavonoids were identified; eleven C-glycosides and five O-glycosides were discovered for the first time in N. nucifera. Most importantly, the C-glycosyl apigenin or luteolin detected in lotus plumules proved valuable for deep elucidation of flavonoid composition in lotus tissues and for further utilization as functional tea and medicine materials. Lotus leaves possessed the significantly highest amount of flavonoids (2.06E3±0.08 mg 100 g−1 FW) and separating and purifying the bioactive compound, quercetin 3-O-glucuronide, from leaves showed great potential. In contrast, flavonoids in flower stalks, seed coats and kernels were extremely low. Simultaneously, the optimal picking time was confirmed by comparing the compound contents in five developmental phases. Finally, we proposed the putative flavonoid biosynthesis pathway in N. nucifera. PMID:25279809

  19. Molecular disassembly of rice and lotus starches during thermal processing and its effect on starch digestibility.

    PubMed

    Wang, Shujun; Sun, Yue; Wang, Jinrong; Wang, Shuo; Copeland, Les

    2016-02-01

    The molecular disassembly of starch during thermal processing is a major determinant for the susceptibility of starch to enzymatic digestion. In the present study, the effects of thermal processing on the disassembly of the granular structure and the in vitro enzymatic digestibility of rice and lotus starches were investigated. After heating at 50 °C, rice and lotus starches did not show significant changes in granular morphology, long-range crystallinity and short-range molecular order. As the temperature increased to 60 °C, rice starch underwent a partial gelatinization followed by an incomplete disruption of granular morphology, crystallites and molecular order. In contrast, lotus starch was almost completely gelatinized at 60 °C. At 70 °C or higher, both starches were fully gelatinized with complete disruption of the micro and macro structures. Our results show that gelatinization greatly increased the in vitro enzymatic digestibility of both starches, but that the degree of disassembly of the starch structure during thermal processing was not a major determinant of the digestibility of gelatinized starch. PMID:26829664

  20. Stomata actively regulate internal aeration of the sacred lotus Nelumbo nucifera.

    PubMed

    Matthews, Philip G D; Seymour, Roger S

    2014-02-01

    The sacred lotus Nelumbo nucifera (Gaertn.) possesses a complex system of gas canals that channel pressurized air from its leaves, down through its petioles and rhizomes, before venting this air back to the atmosphere through large stomata found in the centre of every lotus leaf. These central plate stomata (CPS) lie over a gas canal junction that connects with two-thirds of the gas canals within the leaf blade and with the larger of two discrete pairs of gas canals within the petiole that join with those in the rhizome. It is hypothesized that the lotus actively regulates the pressure, direction and rate of airflow within its gas canals by opening and closing these stomata. Impression casting the CPS reveal that they are open in the morning, close at midday and reopen in the afternoon. The periodic closure of the CPS during the day coincides with a temporary reversal in airflow direction within the petiolar gas canals. Experiments show that the conductance of the CPS decreases in response to increasing light level. This behaviour ventilates the rhizome and possibly directs benthic CO2 towards photosynthesis in the leaves. These results demonstrate a novel function for stomata: the active regulation of convective airflow. PMID:23862628

  1. Genome-Wide Discovery and Analysis of Phased Small Interfering RNAs in Chinese Sacred Lotus

    PubMed Central

    Zheng, Yun; Wang, Shengpeng; Sunkar, Ramanjulu

    2014-01-01

    Phased small interfering RNA (phasiRNA) generating loci (briefly as PHAS) in plants are a novel class of genes that are normally regulated by microRNAs (miRNAs). Similar to miRNAs, phasiRNAs encoded by PHAS play important regulatory roles by targeting protein coding transcripts in plant species. We performed a genome-wide discovery of PHAS loci in Chinese sacred lotus and identified a total of 106 PHAS loci. Of these, 47 loci generate 21 nucleotide (nt) phasiRNAs and 59 loci generate 24 nt phasiRNAs, respectively. We have also identified a new putative TAS3 and a putative TAS4 loci in the lotus genome. Our results show that some of the nucleotide-binding, leucine-rich repeat (NB-LRR) disease resistance proteins and MYB transcription factors potentially generate phasiRNAs. Furthermore, our results suggest that some large subunit (LSU) rRNAs can derive putative phasiRNAs, which is potentially resulted from crosstalk between small RNA biogenesis pathways that are employed to process rRNAs and PHAS loci, respectively. Some of the identified phasiRNAs have putative trans-targets with less than 4 mismatches, suggesting that the identified PHAS are involved in many different pathways. Finally, the discovery of 24 nt PHAS in lotus suggests that there are 24 nt PHAS in dicots. PMID:25469507

  2. Subungual nodule of the great toe.

    PubMed

    Morais, Paulo

    2013-04-01

    An otherwise healthy male, 17 years of age, presented with a 2 year history of an enlarging lump under the right great toenail. There was no history of trauma. Examination revealed an exophytic, non-tender, fixed, firm flesh-coloured subungal nodule on the dorsal aspect of the right great toe. The lesion was about 10 mm in diameter and was associated with nail plate deformity and onycholysis. PMID:23550247

  3. Spontaneous rupture of a splenotic nodule.

    PubMed Central

    Lanigan, D. J.

    1990-01-01

    A case is presented of spontaneous rupture of splenic tissue occurring 14 years after a splenectomy was carried out for trauma. Spontaneous rupture of a splenotic nodule has not previously been described and it may be added to the list of causes of spontaneous haemoperitoneum. The incidence and function of residual splenic tissue are briefly discussed and other causes of splenic rupture are outlined. PMID:2267217

  4. Early diagnosis of solitary pulmonary nodules

    PubMed Central

    Xu, Chunhua; Hao, Keke; Song, Yong; Hou, Zhibo; Zhan, Ping

    2013-01-01

    Early detection of solitary pulmonary nodules (SPNs) and early treatment are of great importance. However, patients with early SPNs always do not present with any symptoms or signs, only to demonstrate SPNs in radiology findings. So it is very critical to improve the ability to identify the SPNs, and with the development of sorts of diagnostic modalities, the accuracy in the evaluation of the SPNs has improved greatly. In this paper, the diagnostic methods and techniques of SPNs are reviewed. PMID:24409362

  5. Hepatic regenerating nodules in hereditary tyrosinemia

    SciTech Connect

    Day, D.L.; Letourneau, J.G.; Allan, B.T.; Sharp, H.L.; Ascher, N.; Dehner, L.P.; Thompson, W.M.

    1987-08-01

    Hereditary tyrosinemia is an autosomal recessive, enzymatic disorder that results in micro- and macronodular cirrhosis in early childhood. Hepatocellular carcinoma occurs in approximately one-third of affected children. We evaluated the imaging studies performed in five children with this disorder. Pathologic examination of all five of the livers revealed cirrhosis and multiple regenerating nodules; hepatocellular carcinoma was present in two of the five livers. All five patients had high-attenuation or high- and low-attenuation foci within the liver. These high-attenuation foci were not apparent as focal lesions in three of four hepatic sonograms or in one of two hepatic nuclear scans. Angiography showed tumor vascularity in one patient with a focal hepatocellular carcinoma, but was indeterminate in a second patient with severe cirrhosis and multifocal hepatocellular carcinoma. Children with cirrhosis due to tyrosinemia may develop regenerating nodules that appear as high-attenuation hepatic foci on CT scans. It is difficult to differentiate regenerating nodules from multifocal hepatocellular carcinoma in these patients.

  6. Pemphigus vulgaris with solitary toxic thyroid nodule.

    PubMed

    Alfishawy, Mostafa; Anwar, Karim; Elbendary, Amira; Daoud, Ahmed

    2014-01-01

    Background. Pemphigus vulgaris is an autoimmune vesiculobullous disease, affecting the skin and mucous membranes. It is reported to be associated with other autoimmune diseases including autoimmune thyroid diseases. However we report herein a case of pemphigus vulgaris associated with autonomous toxic nodule. Case Presentation. A 51-year-old woman was evaluated for blisters and erosions that develop on her trunk, face, and extremities, with a five-year history of progressively enlarging neck mass, and a past medical history of pemphigus vulgaris seven years ago. The condition was associated with palpitation, dyspnea, and heat intolerance. Thyroid function tests and thyroid scan were compatible with the diagnosis of thyrotoxicosis due to autonomous toxic nodule. Exacerbation of pemphigus vulgaris was proved by skin biopsy from the patient which revealed histologic picture of pemphigus vulgaris. Conclusion. Autoimmune thyroid diseases are reported to associate pemphigus vulgaris. To our knowledge, this case is the first in the English literature to report association between pemphigus vulgaris and autonomous toxic nodule and highlights the possibility of occurrence of pemphigus vulgaris with a nonautoimmune thyroid disease raising the question: is it just a coincidence or is there an explanation for the occurrence of both conditions together? PMID:25309761

  7. Distribution of N within Pea, Lupin, and Soybean Nodules.

    PubMed

    Kohl, D H; Reynolds, P H; Shearer, G

    1989-06-01

    The (15)N abundance of some, but not all, legume root nodules is significantly elevated compared to that of the whole plant. It seems probable that differences in (15)N enrichment reflect differences in the assimilatory pathway of fixed N. In that context, we have determined the distribution of naturally occurring (15)N in structural fractions of nodules from soybean (Glycine max L. Merr.), yellow lupin (Lupinus luteus), and pea (Pisum sativum) nodules and in chemical components from soybean nodules and to a lesser extent, pea and lupin nodules. None of the fractions of pea nodules (cortex, bacteriod, or host plant cytoplasm) was enriched in (15)N. The differences among bacteriods, cortex, and plant cytoplasm were smaller in lupin than in soybean nodules, but in both, bacteriods had the highest (15)N enrichment. In soybean nodules, the (15)N abundance of bacteriods and cortex was higher than plant cytoplasm, but all three fractions were more enriched in (15)N than the entire plant. Plant cytoplasm from soybean nodules was fractionated into protein-rich material, nonprotein alcohol precipitable material (NA), and a low molecular weight fraction. The N of the latter was further separated into N of ureides, nucleotides and free amino acids. Most of these components were either similar to or lower in (15)N abundance than the plant cytoplasm as a whole, but the NA fraction showed unusual (15)N enrichment. However, the percentage of nodule N in this fraction was small. NA fractions from yellow lupin and pea nodules and from soybean leaves were not enriched in (15)N. Nor was the NA fraction in ruptured bacteriods and cortical tissue of soybean nodules. Variation among soybean nodule fractions in the preponderance in protein of different amino acids was not large enough to explain the differences in (15)N abundances among them. A hypothesis, consistent with all known data, concerning the mechanism leading to the observed excess (15)N of lupin and soybean bacteriods is

  8. Automated detection of pulmonary nodules from whole lung helical CT scans: performance comparison for isolated and attached nodules

    NASA Astrophysics Data System (ADS)

    Enquobahrie, Andinet A.; Reeves, Anthony P.; Yankelevitz, David F.; Henschke, Claudia I.

    2004-05-01

    The objective of this research is to evaluate and compare the performance of our automated detection algorithm on isolated and attached nodules in whole lung CT scans. Isolated nodules are surrounded by the lung parenchyma with no attachment to large solid structures such as the chest wall or mediastinum surface, while attached nodules are adjacent to these structures. The detection algorithm involves three major stages. First, the region of the image space where pulmonary nodules are to be found is identified. This involves segmenting the lung region and generating the pleural surface. In the second stage, which is the hypothesis generation stage, nodule candidate locations are identified and their sizes are estimated. The nodule candidates are successively refined in the third stage a sequence of filters of increasing complexity. The algorithm was tested on a dataset containing 250 low-dose whole lung CT scans with 2.5mm slice thickness. A scan is composed of images covering the whole lung region for a single person. The dataset was partitioned into 200 and 50 scans for training and testing the algorithm. Only solid nodules were considered in this study. Experienced chest radiologists identified a total of 447 solid nodules. 345 and 102 of the nodules were from the training and testing datasets respectively. 126(28.2%) of the nodules in the dataset were attached nodules. The detection performance was then evaluated separately for isolated and attached nodule types considering different size ranges. For nodules 3mm and larger, the algorithm achieved a sensitivity of 97.8% with 2.0 false positives (FPs) per scan and 95.7% with 19.3 FPs per scan for isolated and attached nodules respectively. For nodules 4mm and larger, a sensitivity of 96.6% with 1.5 FP per scan and a 100% sensitivity with 13 FPs per scan were obtained for isolated and attached nodule types respectively. The results show that our algorithm detects isolated and attached nodules with comparable

  9. Computerized lung nodule detection on screening CT scans: performance on juxta-pleural and internal nodules

    NASA Astrophysics Data System (ADS)

    Sahiner, Berkman; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Zhou, Chuan; Wei, Jun

    2006-03-01

    We are developing a computer-aided detection (CAD) system for lung nodules in thoracic CT volumes. Our CAD system includes an adaptive 3D pre-screening algorithm to segment suspicious objects, and a false-positive (FP) reduction stage to classify the segmented objects as true nodules or normal lung structures. We found that the effectiveness of the FP reduction stage was limited by the different characteristics of the objects in the internal and the juxta-pleural (JP) regions. The purpose of this study was to evaluate object characteristics in the internal and JP regions of a lung CT scan, and to develop different FP reduction classifiers for JP and internal objects. Our FP reduction technique utilized shape, grayscale, and gradient features, as well as the scores of a newly-developed neural network trained on the eigenvalues of the Hessian matrix in a volume of interest containing the suspicious object. We designed an algorithm to automatically label the objects as internal or JP. Based on a training set of 75 CT scans containing internal and JP nodules, two FP classifiers were trained separately for objects in the two types of lung regions. The system performance was evaluated on an independent test set of 27 low dose screening scans. An experienced chest radiologist identified 64 solid nodules (mean diameter: 5.3 mm, range: 3.0-12.9 mm) on the test cases, of which 33 were internal and 31 were JP. Our adaptive 3D prescreening algorithm detected 28 internal and 29 JP nodules. At 80% sensitivity, the average number of FPs was 3.9 and 9.7 in the internal and JP regions per scan, respectively. In comparison, a classifier designed to work on both types of nodules had an average of 29.4 FPs per scan at the same sensitivity. Our results indicate that it is more effective to use two different classifiers for JP and internal nodules because of their different characteristics. FPs in the JP region were more difficult to distinguish from true nodules. Further investigation

  10. Thermal Ablation for Benign Thyroid Nodules: Radiofrequency and Laser

    PubMed Central

    Lee, Jeong Hyun; Valcavi, Roberto; Pacella, Claudio M.; Rhim, Hyunchul; Na, Dong Gyu

    2011-01-01

    Although ethanol ablation has been successfully used to treat cystic thyroid nodules, this procedure is less effective when the thyroid nodules are solid. Radiofrequency (RF) ablation, a newer procedure used to treat malignant liver tumors, has been valuable in the treatment of benign thyroid nodules regardless of the extent of the solid component. This article reviews the basic physics, techniques, applications, results, and complications of thyroid RF ablation, in comparison to laser ablation. PMID:21927553

  11. Cholangicarcinoma Presenting as a Sister Mary Joseph Nodule

    PubMed Central

    Rangegowda, Devaraja; Vyas, Tanmay; Grover, Shrruti; Joshi, YK; Sharma, Chhagan; Sahney, Amrish

    2016-01-01

    Sister Mary Joseph nodules represent metastatic cancer of the umbilicus. More than half of these cases are attributable to gastrointestinal malignancies including gastric, colonic, and pancreatic cancer. In addition, gynecologic (ovarian, uterine cancer), unknown primary tumors, and, rarely, bladder or respiratory malignancies may cause umbilical metastasis. We report the case of a Sister Mary Joseph nodule originating from a hilar cholangiocarcinoma. Umbilical nodules should prompt clinical evaluation, as these tumors are usually associated with poor prognosis. PMID:27144207

  12. Improved pulmonary nodule classification utilizing lung parenchyma texture features

    NASA Astrophysics Data System (ADS)

    Dilger, S. K.; Judisch, A.; Uthoff, J.; Hammond, E.; Newell, J. D.; Sieren, J. C.

    2015-03-01

    Current computer-aided diagnosis (CAD) models, developed to determine the malignancy of pulmonary nodules, characterize the nodule's shape, density, and border. Analyzing the lung parenchyma surrounding the nodule is an area that has been minimally explored. We hypothesize that improved classification of nodules can be achieved through the inclusion of features quantified from the surrounding lung tissue. From computed tomography (CT) data, feature extraction techniques were developed to quantify the parenchymal and nodule textures, including a three-dimensional application of Laws' Texture Energy Measures. Border irregularity was investigated using ray-casting and rubber-band straightening techniques, while histogram features characterized the densities of the nodule and parenchyma. The feature set was reduced by stepwise feature selection to a few independent features that best summarized the dataset. Using leave-one-out cross-validation, a neural network was used for classification. The CAD tool was applied to 50 nodules (22 malignant, 28 benign) from high-resolution CT scans. 47 features, including 39 parenchymal features, were statistically significant, with both nodule and parenchyma features selected for classification, yielding an area under the ROC curve (AUC) of 0.935. This was compared to classification solely based on the nodule yielding an AUC of 0.917. These preliminary results show an increase in performance when the surrounding parenchyma is included in analysis. While modest, the improvement and large number of significant parenchyma features supports our hypothesis that the parenchyma contains meaningful data that can assist in CAD development.

  13. [Factors of multiple resistance to antibiotics in nodule bacteria].

    PubMed

    Pariĭskaia, A N; Gorelova, O P

    1976-01-01

    Multiple resistance to antibiotics (penicillin, levomycetin, neomycin, tetracycline) was found in 15% of collection strains of nodule bacteria and in strains isolated from natural environment. PMID:1050635

  14. Asymptomatic Papulo-nodules Localized to One Finger

    PubMed Central

    Rambhia, Kinjal D; Khopkar, Uday S

    2015-01-01

    Subcutaneous or deep granuloma annulare is a benign asymptomatic condition characterized by firm asymptomatic nodules in deep subcutaneous tissues that may be associated with intradermal lesions. A 53-year-old female presented with asymptomatic skin-colored, firm nodules over the right ring finger. Histopathology revealed a palisading granuloma with central degenerated collagen and mucin deposition in the dermis suggestive of granuloma annulare. Isolated and unilateral involvement of a single digit with clusters of nodules of subcutaneous granuloma annulare (GA) in an adult is rare and differentiation from its simulator rheumatoid nodule is essential. PMID:26538728

  15. Analysis of Flavonoids in Lotus (Nelumbo nucifera) Leaves and Their Antioxidant Activity Using Macroporous Resin Chromatography Coupled with LC-MS/MS and Antioxidant Biochemical Assays.

    PubMed

    Zhu, Ming-Zhi; Wu, Wei; Jiao, Li-Li; Yang, Ping-Fang; Guo, Ming-Quan

    2015-01-01

    Lotus (Nelumbo nucifera) leaves, a traditional Chinese medicinal herb, are rich in flavonoids. In an effort to thoroughly analyze their flavonoid components, macroporous resin chromatography coupled with HPLC-MS/MS was employed to simultaneously enrich and identify flavonoids from lotus leaves. Flavonoids extracted from lotus leaves were selectively enriched in the macroporous resin column, eluted subsequently as fraction II, and successively subjected to analysis with the HPLC-MS/MS and bioactivity assays. Altogether, fourteen flavonoids were identified, four of which were identified from lotus leaves for the first time, including quercetin 3-O-rhamnopyranosyl-(1→2)-glucopyranoside, quercetin 3-O-arabinoside, diosmetin 7-O-hexose, and isorhamnetin 3-O-arabino- pyranosyl-(1→2)-glucopyranoside. Further bioactivity assays revealed that these flavonoids from lotus leaves possess strong antioxidant activity, and demonstrate very good potential to be explored as food supplements or even pharmaceutical products to improve human health. PMID:26060918

  16. Evolutionary signals of symbiotic persistence in the legume–rhizobia mutualism

    PubMed Central

    Werner, Gijsbert D. A.; Cornwell, William K.; Cornelissen, Johannes H. C.; Kiers, E. Toby

    2015-01-01

    Understanding the origins and evolutionary trajectories of symbiotic partnerships remains a major challenge. Why are some symbioses lost over evolutionary time whereas others become crucial for survival? Here, we use a quantitative trait reconstruction method to characterize different evolutionary stages in the ancient symbiosis between legumes (Fabaceae) and nitrogen-fixing bacteria, asking how labile is symbiosis across different host clades. We find that more than half of the 1,195 extant nodulating legumes analyzed have a high likelihood (>95%) of being in a state of high symbiotic persistence, meaning that they show a continued capacity to form the symbiosis over evolutionary time, even though the partnership has remained facultative and is not obligate. To explore patterns associated with the likelihood of loss and retention of the N2-fixing symbiosis, we tested for correlations between symbiotic persistence and legume distribution, climate, soil and trait data. We found a strong latitudinal effect and demonstrated that low mean annual temperatures are associated with high symbiotic persistence in legumes. Although no significant correlations between soil variables and symbiotic persistence were found, nitrogen and phosphorus leaf contents were positively correlated with legumes in a state of high symbiotic persistence. This pattern suggests that highly demanding nutrient lifestyles are associated with more stable partnerships, potentially because they “lock” the hosts into symbiotic dependency. Quantitative reconstruction methods are emerging as a powerful comparative tool to study broad patterns of symbiont loss and retention across diverse partnerships. PMID:26041807

  17. [Symbiotic matching between soybean cultivar Luhuang No. 1 and different rhizobia].

    PubMed

    Ji, Zhao-jun; Wang, Fei-meng; Wang, Su-ge; Yang, Sheng-hui; Guo, Rui; Tang, Ru-you; Chen, Wen-xin; Chen, Wen-feng

    2014-12-01

    Soybean plants could establish symbiosis and fix nitrogen with different rhizobial species in the genera of Sinorhizobium and Bradyrhizobium. Studies on the symbiotic matching between soybean cultivars and different rhizobial species are theoretically and practically important for selecting effective strains used to inoculate the plants and improve the soybean production and quality. A total of 27 strains were isolated and purified from a soil sample of Huanghuaihai area by using the soybean cultivar Luhang No. 1, a protein-rich cultivar grown in that area, as the trapping plants. These strains were identified as members of Sinorhizobium (18 strains) and Bradyrhizobium (9 strains) based on the sequence analysis of housekeeping gene recA. Two representative strains (Sinorhizobium fredii S6 and Bradyrhizobium sp. S10) were used to inoculate the seeds of Luhang No. 1 alone or mixed, in pots filled with vermiculite or soil, and in the field trial to investigate their effects on soybean growth, nodulation, nitrogen fixation activity, yield, contents of protein and oil in seeds. The results demonstrated that strain S6 showed better effects on growth-promotion, yield of seeds and seed quality than strain S10. Thus strain S6 was finally regarded as the effective rhizobium matching to soybean Luhuang No. 1, which could be the candidate as a good inoculant for planting the soybean Luhuang No. 1 at a large scale in the Huanghuaihai area. PMID:25876410

  18. Evolutionary signals of symbiotic persistence in the legume-rhizobia mutualism.

    PubMed

    Werner, Gijsbert D A; Cornwell, William K; Cornelissen, Johannes H C; Kiers, E Toby

    2015-08-18

    Understanding the origins and evolutionary trajectories of symbiotic partnerships remains a major challenge. Why are some symbioses lost over evolutionary time whereas others become crucial for survival? Here, we use a quantitative trait reconstruction method to characterize different evolutionary stages in the ancient symbiosis between legumes (Fabaceae) and nitrogen-fixing bacteria, asking how labile is symbiosis across different host clades. We find that more than half of the 1,195 extant nodulating legumes analyzed have a high likelihood (>95%) of being in a state of high symbiotic persistence, meaning that they show a continued capacity to form the symbiosis over evolutionary time, even though the partnership has remained facultative and is not obligate. To explore patterns associated with the likelihood of loss and retention of the N2-fixing symbiosis, we tested for correlations between symbiotic persistence and legume distribution, climate, soil and trait data. We found a strong latitudinal effect and demonstrated that low mean annual temperatures are associated with high symbiotic persistence in legumes. Although no significant correlations between soil variables and symbiotic persistence were found, nitrogen and phosphorus leaf contents were positively correlated with legumes in a state of high symbiotic persistence. This pattern suggests that highly demanding nutrient lifestyles are associated with more stable partnerships, potentially because they "lock" the hosts into symbiotic dependency. Quantitative reconstruction methods are emerging as a powerful comparative tool to study broad patterns of symbiont loss and retention across diverse partnerships. PMID:26041807

  19. Decision making in patients with pulmonary nodules.

    PubMed

    Ost, David E; Gould, Michael K

    2012-02-15

    Integrating current evidence with fundamental concepts from decision analysis suggests that management of patients with pulmonary nodules should begin with estimating the pretest probability of cancer from the patient's clinical risk factors and computed tomography characteristics. Then, the consequences of treatment should be considered, by comparing the benefits of surgery if the patient has lung cancer with the potential harm if the patient does not have cancer. This analysis determines the "treatment threshold," which is the point around which the decision centers. This varies widely among patients depending on their cardiopulmonary reserve, comorbidities, and individual preferences. For patients with a very low probability of cancer, careful observation with serial computed tomography is warranted. For those with a high probability of cancer, surgical diagnosis is warranted. For patients in the intermediate range of probabilities, either computed tomography-guided fine-needle aspiration biopsy or positron emission tomography, possibly followed by computed tomography-guided fine-needle aspiration biopsy, is best. Patient preferences should be considered because the absolute difference in outcome between strategies may be small. The optimal approach to the management of patients with pulmonary nodules is evolving as technologies develop. Areas of uncertainty include quantifying the hazard of delayed diagnosis; determining the optimal duration of follow-up for ground-glass and semisolid opacities; establishing the roles of volumetric imaging, advanced bronchoscopic technologies, and limited surgical resections; and calculating the cost-effectiveness of different strategies. PMID:21980032

  20. Surgical approach to thyroid nodules and cancer.

    PubMed

    Oertli, D; Harder, F

    2000-12-01

    Fine needle aspiration cytology is the mainstay of the diagnostic work-up of solitary thyroid nodules. Together with the patient's history and the clinical findings, cytology determines the indication for surgery. The minimal intervention for a suspicious nodule consists of thyroid lobectomy. If a diagnosis of malignancy is established, then we recommend total thyroidectomy for all follicular lesions that are larger than 1.5 cm and for high-risk papillary tumours. Near-total thyroidectomy may be appropriate for low-risk patients with papillary carcinoma in whom it is not intended to use radioactive iodine ablation. Whereas ipsilateral lymphadenectomy of the central (primary) compartment should routinely be performed, modified radical neck dissection is only indicated in evident nodal disease of the lateral (secondary) compartment(s). Patients with incidentally discovered differentiated thyroid carcinomas generally do not require complete thyroidectomy unless the tumours are larger than 1.5 cm in diameter or nodal involvement is present. A detailed description of the surgical technique for thyroidectomy and lymphadenectomy is given and an overview of surgical complications is provided. PMID:11289740

  1. Growth of fast- and slow-growing rhizobia on ethanol. [Bradyrhizobium sp. ; Rhizobium meliloti; Rhizobium loti; Rhizobium leguminosarum; Rhizobium fredii; Bradyrhizobium japonicum

    SciTech Connect

    Sadowsky, M.J.; Bohlool, B.B.

    1986-10-01

    Free-living soybean rhizobia and Bradyrhizobium spp. (lupine) have the ability to catabolize ethanol. Of the 30 strains of rhizobia examined, only the fast- and slow-growing soybean rhizobia and the slow-growing Bradyrhizobium sp (lupine) were capable of using ethanol as a sole source of carbon and energy for growth. Two strains from each of the other Rhizobium species examined (R. meliloti, R. loti, and R. leguminosarum biovars phaseoli, trifolii, and viceae) failed to grow on ethanol. One Rhizobium fredii (fast-growing) strain, USDA 191, and one (slow-growing) Bradyrhizobium japonicum strain, USDA 110, grew in ethanol up to concentrations of 3.0 and 1.0%, respectively. While three of the R. fredii strains examined (USDA 192, USDA 194, and USDA 205) utilized 0.2% acetate, only USDA 192 utilized 0.1% n-propanol. None of the three strains utilized 0.1% methanol, formate, or n-butanol as the sole carbon source.

  2. LOTUS' Preparing Sentinel-3 Ocean and Land SAR Altimetry Processing for Copernicus

    NASA Astrophysics Data System (ADS)

    Knudsen, Per; Andersen, Ole; Nielsen, Karina; Pelloquin, Camille; Berry, Philippa; Thibaut, Pierre; Moreau, Thomas; Bauer-Gottwein, Peter; Madsen, Henrik; Petersen, Ole S.

    2015-04-01

    The Sentinel-3 satellite mission with its SRAL instrumentation contains new features compared to the conventional radar altimeter mission that form the basis for new innovative GMES products and applications that are not considered or implemented in the Copernicus services yet. To utilize the full potential of the new data source, new methods and processing chains need to be developed. Also, new potential Copernicus products should be developed that utilize the improved along-track resolution over both the oceans and over land. Then new operational processing, validation and delivery mechanisms need to be developed and implemented for generating the new dynamic products. A smooth transition from old to new products is important to ensure existing services. Finally, the take-up of the new Copernicus products by the value-adding sectors needs to be stimulated and demonstrated to ensure that they will be used for commercial activities. The main objective of the LOTUS project is to prepare the take-up of data from Sentinels 3. In the initial phase, LOTUS has developed processing schemes for extracting high-resolution sea surface heights, wave heights and wind speeds from SAR mode data. Over land, the LOTUS has developed processing scheme for extracting high-resolution river and lake heights. Processing for soil moisture, and snow depth is undergoing. This presentation shows some preliminary results based on analyses using CRYOSAT data. Furthermore, new DEMO data sets are presented. These data sets facilitate the development of marine and hydrological services for Copernicus and the down-stream segment.

  3. Comet 67P observations with LOTUS: a new near-UV spectrograph for the Liverpool Telescope

    NASA Astrophysics Data System (ADS)

    Marchant, Jon; Jermak, Helen; Steele, Iain; Snodgrass, Colin; Fitzsimmons, Alan; Jones, Geraint

    2015-11-01

    The European Space Agency’s Rosetta spacecraft has been orbiting comet 67P/Churyumov-Gerasimenko (hereinafter “67P”) since August 2014, providing in-situ measurements of the dust, gas and plasma content of the coma within ~100km of the nucleus. Supporting the mission is a world-wide coordinated campaign of simultaneous ground-based observations of 67P (www.rosetta-campaign.net), providing wider context of the outer coma and tail invisible to Rosetta. We can now compare these observations, augmented by "ground truth" from Rosetta, with those of other comets past and future that are only observed from Earth.The robotic Liverpool Telescope (LT) is part of this campaign due to its unique ability to flexibly and autonomously schedule regular observations over entire semesters. Its optical imagery has recently been supplemented by near-UV spectroscopy to observe the UV molecular bands below 4000Å that are of considerable interest to cometary science. The LT's existing spectrographs FRODOSpec and SPRAT cut off at 4000Å, so the Liverpool Telescope Optical-to-UV Spectrograph - LOTUS - was fast-track designed, built and deployed on-sky in just five months. LOTUS contains no moving parts; acquisition is made with the LT's IO:O imaging camera, and different width slits for calibration and science are selected by fine-tuning the telescope's pointing on an innovative "step" design in its single slit.We present here details of the LOTUS spectrograph, and some preliminary results of our ongoing observations of comet 67P.

  4. Effect of lectin on nodulation by wild-type Bradyrhizobium japonicum and a nodulation-defective mutant.

    PubMed Central

    Halverson, L J; Stacey, G

    1986-01-01

    The nodulation characteristics of wild-type Bradyrhizobium japonicum USDA 110 and mutant strain HS111 were examined. Mutant strain HS111 exhibits a delayed-nodulation phenotype, a result of its inability to initiate successful nodulation promptly following inoculation of the soybean root. Previously, we showed that the defect in initiation of infection leading to subsequent nodulation which is found in HS111 can be phenotypically reversed by pretreatment with soybean root exudate or soybean seed lectin. This effect is not seen after pretreatment with root exudates and lectins obtained from other plant species. Treatment of strain HS111 with as little as 10 soybean seed lectin molecules per bacterium (3.3 X 10 (-12) M) resulted in enhancement of nodule formation. Pretreatment of wild-type B. japonicum USDA 110 with soybean root exudate or seed lectin increased nodule numbers twofold on 6-week-old plants. Wild-type strain USDA 110 cells inoculated at 10(4) cells per seedling exhibited a delay in initiation of infection leading to subsequent nodulation. Wild-type cells pretreated in soybean root exudates or seed lectin did not exhibit a delay in nodulation at this cell concentration. Mutant strain HS111 pretreated in seed lectin for 0 or 1 h, followed by washing with the hapten D-galactose to remove the lectin, exhibited a delay in initiation of nodulation. Phenotypic reversal of the delayed-nodulation phenotype exhibited by strain HS111 was seen if incubation was continued for an additional 71 h in plant nutrient solution following 1 h of lectin pretreatment. Reversal of the delayed-nodulation phenotype of HS111 through lectin pretreatment was prevented by chloramphenicol or rifampin.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3707122

  5. Ferric Leghemoglobin in Plant-Attached Leguminous Nodules.

    PubMed Central

    Lee, Kk.; Shearman, L. L.; Erickson, B. K.; Klucas, R. V.

    1995-01-01

    Leghemoglobin (Lb) is essential for nitrogen fixation by intact leguminous nodules. To determine whether ferric Lb (Lb3+) was detectable in nodules under normal or stressed conditions, we monitored the status of Lb in intact nodules attached to sweet clover (Melilotus officinalis) and soybean (Glycine max [L.] Merr.) roots exposed to various conditions. The effects of N2 and O2 streams and elevated nicotinate levels on root-attached nodules were tested to determine whether the spectrophotometric technique was showing the predicted responses of Lb. The soybean and sweet clover nodules' Lb spectra indicated predominantly ferrous Lb and LbO2 in young (34 d) plants. As the nodule aged beyond 45 d, it was possible to induce Lb3+ with a 100% O2 stream (15 min). At 65 d without inducement, the nodule Lb status indicated the presence of some Lb3+ along with ferrous Lb and oxyferrous Lb. Nicotinate and fluoride were used as ligands to identify Lb3+. Computer-calculated difference spectra were used to demonstrate the changes in Lb spectra under different conditions. Some conditions that increased absorbance in the 626 nm region (indicating Lb3+ accumulation) were root-fed ascorbate and dehydroascorbate, plant exposure to darkness, and nodule water immersion. PMID:12228593

  6. Next Generation Metallic Iron Nodule Technology in Electric Furnace Steelmaking

    SciTech Connect

    2007-09-01

    This factsheet describes a research project whose objective is to investigate reducing processing temperature, controlling the gas temperature and gas atmosphere over metallized iron nodules, and effectively using sub-bituminous coal as a reductant for producing high quality metallized iron nodules at low cost.

  7. Glutamate Oxaloacetate Transaminase in Pea Root Nodules 1

    PubMed Central

    Appels, Michiel A.; Haaker, Huub

    1991-01-01

    Glutamate oxaloacetate transaminase (l-glutamate: oxaloacetate aminotransferase, EC 2.6.1.1 [GOT]), a key enzyme in the flow of carbon between the organic acid and amino acid pools in pea (Pisum sativum L.) root nodules, was studied. By ion exchange chromatography, the presence of two forms of GOT in the cytoplasm of pea root nodule cells was established. The major root nodule form was present in only a small quantity in the cytoplasm of root cells. Fractionation of root nodule cell extracts demonstrated that the increase in the GOT activity during nodule development was due to the increase of the activity in the cytoplasm of the plant cells, and not to an increase in activity in the plastids or in the mitochondria. The kinetic properties of the different cytoplasmic forms of GOT were studied. Some of the Km values differed, but calculations indicated that not the kinetic properties but a high concentration of the major root nodule form caused the observed increase in GOT activity in the pea root nodules. It was found that the reactions of the malate/aspartate shuttle are catalyzed by intact bacteroids, and that these reactions can support nitrogen fixation. It is proposed that the main function of the nodule-stimulated cytoplasmic form of GOT is participation in this shuttle. PMID:16668048

  8. Hashimoto's thyroiditis presenting as hot and cold nodules

    SciTech Connect

    Sulimani, R.A.; el-Desouki, M. )

    1990-05-01

    A case of Hashimoto's thyroiditis is presented. I-123 thyroid scintigraphy demonstrated a hot nodule in the left lobe and a cold nodule in the right, which was well visualized by Tl-201 imaging. This unusual scintigraphic appearance is demonstrated, and its possible explanation discussed.

  9. Evidence based imaging strategies for solitary pulmonary nodule

    PubMed Central

    Gong, Jing-Shan; Suzuki, Kenji; Morcos, Sameh K.

    2014-01-01

    Solitary pulmonary nodule (SPN) is defined as a rounded opacity ≤3 cm in diameter surrounded by lung parenchyma. The majority of smokers who undergo thin-section CT have SPNs, most of which are smaller than 7 mm. In the past, multiple follow-up examinations over a two-year period, including CT follow-up at 3, 6, 12, 18, and 24 months, were recommended when such nodules are detected incidentally. This policy increases radiation burden for the affected population. Nodule features such as shape, edge characteristics, cavitation, and location have not yet been found to be accurate for distinguishing benign from malignant nodules. When SPN is considered to be indeterminate in the initial exam, the risk factor of the patients should be evaluated, which includes patients’ age and smoking history. The 2005 Fleischner Society guideline stated that at least 99% of all nodules 4 mm or smaller are benign; when nodule is 5-9 mm in diameter, the best strategy is surveillance. The timing of these control examinations varies according to the nodule size (4-6, or 6-8 mm) and the type of patients, specifically at low or high risk of malignancy concerned. Noncalcified nodules larger than 8 mm diameter bear a substantial risk of malignancy, additional options such as contrast material-enhanced CT, positron emission tomography (PET), percutaneous needle biopsy, and thoracoscopic resection or videoassisted thoracoscopic resection should be considered. PMID:25093083

  10. Surgical and Pathological Changes after Radiofrequency Ablation of Thyroid Nodules

    PubMed Central

    Dobrinja, Chiara; Bernardi, Stella; Fabris, Bruno; Eramo, Rita; Makovac, Petra; Bazzocchi, Gabriele; Piscopello, Lanfranco; Barro, Enrica; de Manzini, Nicolò; Bonazza, Deborah; Pinamonti, Maurizio; Zanconati, Fabrizio; Stacul, Fulvio

    2015-01-01

    Background. Radiofrequency ablation (RFA) has been recently advocated as an effective technique for the treatment of symptomatic benign thyroid nodules. It is not known to what extent it may affect any subsequent thyroid surgery and/or histological diagnosis. Materials and Methods. RFA was performed on 64 symptomatic Thy2 nodules (benign nodules) and 6 symptomatic Thy3 nodules (follicular lesions/follicular neoplasms). Two Thy3 nodules regrew after the procedure, and these patients accepted to undergo a total thyroidectomy. Here we present how RFA has affected the operation and the final pathological features of the surgically removed nodules. Results and Conclusions. RFA is effective for the treatment of Thy2 nodules, but it should not be recommended as first-line therapy for the treatment of Thy3 nodules (irrespective of their mutational status), as it delays surgery in case of malignancy. Moreover, it is unknown whether RFA might promote residual tumor progression or neoplastic progression of Thy3 lesions. Nevertheless, here we show for the first time that one session of RFA does not affect subsequent thyroid surgery and/or histological diagnosis. PMID:26265914

  11. Chest xerotomography: evaluation of calcification within lung nodules.

    PubMed

    Penkrot, R J; Gordon, R

    1980-01-01

    Through the use of a chest phantom and beeswax nodules containing calcium, xerotomography is shown to be a valuable tool in the evaluation of calcifications within lung nodules. The technique gives superior definition of calcium, especially fine calcifications in the 1-2-mm, or less, range. Our results suggest that clinical trials should follow and clinicopathologic correlation be obtained. PMID:7203908

  12. E151 (sym15), a pleiotropic mutant of pea (Pisum sativum L.), displays low nodule number, enhanced mycorrhizae, delayed lateral root emergence, and high root cytokinin levels

    PubMed Central

    Jones, James M. C.; Clairmont, Lindsey; Macdonald, Emily S.; Weiner, Catherine A.; Emery, R. J. Neil; Guinel, Frédérique C.

    2015-01-01

    In legumes, the formation of rhizobial and mycorrhizal root symbioses is a highly regulated process which requires close communication between plant and microorganism. Plant mutants that have difficulties establishing symbioses are valuable tools for unravelling the mechanisms by which these symbioses are formed and regulated. Here E151, a mutant of Pisum sativum cv. Sparkle, was examined to characterize its root growth and symbiotic defects. The symbioses in terms of colonization intensity, functionality of micro-symbionts, and organ dominance were compared between the mutant and wild type. The endogenous cytokinin (CK) and abscisic acid (ABA) levels and the effect of the exogenous application of these two hormones were determined. E151 was found to be a low and delayed nodulator, exhibiting defects in both the epidermal and cortical programmes though a few mature and functional nodules develop. Mycorrhizal colonization of E151 was intensified, although the fungal functionality was impaired. Furthermore, E151 displayed an altered lateral root (LR) phenotype compared with that of the wild type whereby LR emergence is initially delayed but eventually overcome. No differences in ABA levels were found between the mutant and the wild type, but non-inoculated E151 exhibited significantly high CK levels. It is hypothesized that CK plays an essential role in differentially mediating the entry of the two micro-symbionts into the cortex; whereas it would inhibit the entry of the rhizobia in that tissue, it would promote that of the fungus. E151 is a developmental mutant which may prove to be a useful tool in further understanding the role of hormones in the regulation of beneficial root symbioses. PMID:25948707

  13. Biosynthesis of compatible solutes in rhizobial strains isolated from Phaseolus vulgaris nodules in Tunisian fields

    PubMed Central

    2010-01-01

    Background 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 osmoadaptation have focussed on the model species Sinorhizobium meliloti, little is known on the osmoadaptive mechanisms used by native rhizobia, which are good sources of inoculants. In this work, we investigated the synthesis and accumulations of compatible solutes by four rhizobial strains isolated from root nodules of Phaseolus vulgaris in Tunisia, as well as by the reference strain Rhizobium tropici CIAT 899T. Results The most NaCl-tolerant strain was A. tumefaciens 10c2, followed (in decreasing order) by R. tropici CIAT 899, R. leguminosarum bv. phaseoli 31c3, R. etli 12a3 and R. gallicum bv. phaseoli 8a3. 13C- and 1H-NMR analyses showed that all Rhizobium strains synthesized trehalose whereas A. tumefaciens 10c2 synthesized mannosucrose. Glutamate synthesis was also observed in R. tropici CIAT 899, R. leguminosarum bv. phaseoli 31c3 and A. tumefaciens 10c2. When added as a carbon source, mannitol was also accumulated by all strains. Accumulation of trehalose in R. tropici CIAT 899 and of mannosucrose in A. tumefaciens 10c2 was osmoregulated, suggesting their involvement in osmotolerance. The phylogenetic analysis of the otsA gene, encoding the trehalose-6-phosphate synthase, suggested the existence of lateral transfer events. In vivo 13C labeling experiments together with genomic analysis led us to propose the uptake and conversion pathways of different carbon sources into trehalose. Collaterally, the β-1,2-cyclic glucan from R. tropici CIAT 899 was co

  14. [Evaluation of antifungal and mollusuicidial activities of Moroccan Zizyphus lotus (L.) Desf].

    PubMed

    Lahlou, M; El Mahi, M; Hamamouchi, J

    2002-11-01

    Zizyphus lotus (L.) Desf. is one of the traditional drugs commonly used in folk medicine in Morocco. Extracts obtained from the successive exhaustion in petroleum ether, chloroform, ethyl acetate and methanol were in vitro found active either against nine pathogenic fungi and Bulinus truncatus, the intermediate host and vector of transmission of unitary schistosomiasis in Morocco. Particularly, the chloroform extract appears the most interesting in antifungal tests at lowest concentrations because of its countenance on terpenic compounds. Whereas, methanolic extract was found to possess the strong mollusuicidial activity and exhibited potent "knock-down" effect on molluscans related to its countenance on saponins. PMID:12514508

  15. The mitochondrial genome of the American lotus borer, Ostrinia penitalis (Lepidoptera: Crambidae).

    PubMed

    Coates, Brad S; Abel, Craig A

    2016-05-01

    The American lotus borer, Ostrinia penitalis, is the most ancestral among more than 20 species described in the genus Ostrinia, and the near complete mitochondrial genome sequence described here is important for phylogenetic comparisons. The 12,612 bp contiguous fragment contains 13 protein coding genes, 20 tRNAs and a partial rRNA gene complement. Compared to two previously sequenced Ostrinia mitochondrial genomes, gene order and orientation remains identical. In contrast, complete stop codons of cox2 (TAG) and atp6 (TAA) in O. penitalis show that completion of truncated stop codons in other Ostrinia are derived. PMID:25329261

  16. A lotus root-like appearance in carotid stenosis on optical coherence tomography.

    PubMed

    Chang, Hyukwon; Yoon, Hyuck Jun; Hong, Jeong-Ho; Kim, Chang-Hyun; Sohn, Sung-Il; Lee, Chang-Young

    2016-06-01

    An 82-year-old man visited the outpatient clinic of our stroke centre because of dizziness. He had a previous history of stroke without definite sequelae. Severe stenosis in the left proximal internal carotid artery (ICA) was seen on Doppler sonography. Conventional angiography revealed focal severe stenosis with 'string sign' in the left proximal ICA and delayed distal run off. Optical coherence tomography showed multiple channels surrounding a narrowed central lumen (lotus root-like appearance). Carotid stent placement with a protection device was done without complications. The patient was discharged in good condition 5 days after the procedure. PMID:25999379

  17. Zizyphus lotus L. (Desf.) modulates antioxidant activity and human T-cell proliferation

    PubMed Central

    2010-01-01

    Background Zizyphus lotus L. (Desf.) also known as Jujube, is a deciduous shrub which belongs to Rhamnaceae family. This plant is used in Algerian traditional medicine for its anti-diabetic, sedative, analgesic, anti-inflammatory and hypoglycaemic activities. In the present study, we determined the concentrations of different vitamins (vitamin A, C and E) and fatty acids in root, stem, leaves, fruit pulp and seed of Zizyphus lotus L. (Desf.) and assessed the effects of their aqueous extracts on antioxidant status and human T-cell proliferation. Methods Aqueous filtrates from different parts, i.e, root, leaf, stem, fruit pulp and seed, of Zizyphus lotus L. (Desf.) were prepared. Vitamin C levels were determined by precipitating with 10% trichloroacetic acid and vitamin A and E were assessed by HPLC. Lipid composition of these extracts was determined by gas-liquid chromatography. Anti-oxidant capacity was evaluated by using anti-radical resistance kit [Kit Radicaux Libres (KRL@; Kirial International SA, Couternon, France)]. T-cell blastogenesis was assessed by the incorporation of 3H-thymidine. IL-2 gene expression was evaluated by RT-qPCR. Results Our results show that fruit pulp contained higher vitamin A and C contents than other parts of the plant. Furthermore, the fruit pulp was the richest source of linoleic acid (18:2n-6), a precursor of n-6 fatty acids. Fruit seeds possessed higher vitamin C levels than leaves, roots and stem. The leaves were the richest source of vitamin E and linolenic acid (18:3n-3), a precursor of n-3 fatty acids. The antioxidant capacity of the different extracts, measured by KRL@ test, was as follows: pulp < seedlotus L. (Desf.) exerted immunosuppressive effects. Conclusion Seed extracts exerted the most potent immunosuppressive effects on T cell proliferation and IL-2 mRNA expression. The results of the present study are

  18. Lithium Blanket Module dosimetry measurements at the LOTUS 14-MeV neutron source facility

    SciTech Connect

    Tsang, F.Y.; Leo, W.R.; Sahraoui, C.; Wuthrich, S.; Harker, Y.D.

    1986-01-01

    This paper describes the measurements and results of the dosimeter material reaction rates inside the Lithium Blanket Module (LBM) after irradiation by the LOTUS 14-MeV neutron source at the Ecole Polytechnique Federale de Lausanne. The measurement program has been designed to utilize sets of passive dosimeter materials in the form of foils and wires. The dosimetry materials reaction thresholds and interaction response ranges chosen for this series of measurements encompass the entire neutron spectra along the full length of the LBM fuel rods.

  19. Biochemical and Molecular Phylogenetic Study of Agriculturally Useful Association of a Nitrogen-Fixing Cyanobacterium and Nodule Sinorhizobium with Medicago sativa L.

    PubMed Central

    Karaushu, E. V.; Kravzova, T. R.; Vorobey, N. A.; Kiriziy, D. A.; Olkhovich, O. P.; Taran, N. Yu.; Kots, S. Ya.; Omarova, E.

    2015-01-01

    Seed inoculation with bacterial consortium was found to increase legume yield, providing a higher growth than the standard nitrogen treatment methods. Alfalfa plants were inoculated by mono- and binary compositions of nitrogen-fixing microorganisms. Their physiological and biochemical properties were estimated. Inoculation by microbial consortium of Sinorhizobium meliloti T17 together with a new cyanobacterial isolate Nostoc PTV was more efficient than the single-rhizobium strain inoculation. This treatment provides an intensification of the processes of biological nitrogen fixation by rhizobia bacteria in the root nodules and an intensification of plant photosynthesis. Inoculation by bacterial consortium stimulates growth of plant mass and rhizogenesis and leads to increased productivity of alfalfa and to improving the amino acid composition of plant leaves. The full nucleotide sequence of the rRNA gene cluster and partial sequence of the dinitrogenase reductase (nifH) gene of Nostoc PTV were deposited to GenBank (JQ259185.1, JQ259186.1). Comparison of these gene sequences of Nostoc PTV with all sequences present at the GenBank shows that this cyanobacterial strain does not have 100% identity with any organisms investigated previously. Phylogenetic analysis showed that this cyanobacterium clustered with high credibility values with Nostoc muscorum. PMID:26114100

  20. Plant Hormonal Regulation of Nitrogen-Fixing Nodule Organogenesis

    PubMed Central

    Ryu, Hojin; Cho, Hyunwoo; Choi, Daeseok; Hwang, Ildoo

    2012-01-01

    Legumes have evolved symbiotic interactions with rhizobial bacteria to efficiently utilize nitrogen. Recent progress in symbiosis has revealed several key components of host plants required for nitrogen-fixing nodule organogenesis, in which complicated metabolic and signaling pathways in the host plant are reprogrammed to generate nodules in the cortex upon perception of the rhizobial Nod factor. Following the recognition of Nod factors, plant hormones are likely to be essential throughout nodule organogenesis for integration of developmental and environmental signaling cues into nodule development. Here, we review the molecular events involved in plant hormonal regulation and signaling cross-talk for nitrogen-fixing nodule development, and discuss how these signaling networks are integrated into Nod factor-mediated signaling during plant-microbe interactions. PMID:22820920