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Sample records for azospirillum sp b510

  1. Network Analysis of Plasmidomes: The Azospirillum brasilense Sp245 Case

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    Valerio Orlandini

    2014-01-01

    Full Text Available Azospirillum brasilense is a nitrogen-fixing bacterium living in association with plant roots. The genome of the strain Sp245, isolated in Brazil from wheat roots, consists of one chromosome and six plasmids. In this work, the A. brasilense Sp245 plasmids were analyzed in order to shed some light on the evolutionary pathways they followed over time. To this purpose, a similarity network approach was applied in order to identify the evolutionary relationships among all the A. brasilense plasmids encoded proteins; in this context a computational pipeline specifically devoted to the analysis and the visualization of the network-like evolutionary relationships among different plasmids molecules was developed. This information was supplemented with a detailed (in silico functional characterization of both the connected (i.e., sharing homology with other sequences in the dataset and the unconnected (i.e., not sharing homology components of the network. Furthermore, the most likely source organism for each of the genes encoded by A. brasilense plasmids was checked, allowing the identification of possible trends of gene loss/gain in this microorganism. Data obtained provided a detailed description of the evolutionary landscape of the plasmids of A. brasilense Sp245, suggesting some of the molecular mechanisms responsible for the present-day structure of these molecules.

  2. Network Analysis of Plasmidomes: The Azospirillum brasilense Sp245 Case.

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    Orlandini, Valerio; Emiliani, Giovanni; Fondi, Marco; Maida, Isabel; Perrin, Elena; Fani, Renato

    2014-01-01

    Azospirillum brasilense is a nitrogen-fixing bacterium living in association with plant roots. The genome of the strain Sp245, isolated in Brazil from wheat roots, consists of one chromosome and six plasmids. In this work, the A. brasilense Sp245 plasmids were analyzed in order to shed some light on the evolutionary pathways they followed over time. To this purpose, a similarity network approach was applied in order to identify the evolutionary relationships among all the A. brasilense plasmids encoded proteins; in this context a computational pipeline specifically devoted to the analysis and the visualization of the network-like evolutionary relationships among different plasmids molecules was developed. This information was supplemented with a detailed (in silico) functional characterization of both the connected (i.e., sharing homology with other sequences in the dataset) and the unconnected (i.e., not sharing homology) components of the network. Furthermore, the most likely source organism for each of the genes encoded by A. brasilense plasmids was checked, allowing the identification of possible trends of gene loss/gain in this microorganism. Data obtained provided a detailed description of the evolutionary landscape of the plasmids of A. brasilense Sp245, suggesting some of the molecular mechanisms responsible for the present-day structure of these molecules.

  3. Azospirillum canadense sp. nov., a nitrogen-fixing bacterium isolated from corn rhizosphere.

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    Mehnaz, Samina; Weselowski, Brian; Lazarovits, George

    2007-03-01

    A free-living diazotrophic strain, DS2(T), was isolated from corn rhizosphere. Polyphasic taxonomy was performed including morphological characterization, Biolog analysis, and 16S rRNA, cpn60 and nifH gene sequence analyses. 16S rRNA gene sequence analysis indicated that strain DS2(T) was closely related to the genus Azospirillum (96 % similarity). Chemotaxonomic characteristics (DNA G+C content 67.9 mol%; Q-10 quinone system; major fatty acid 18 : 1omega7c) were also similar to those of the genus Azospirillum. In all the analyses, including phenotypic characterization using Biolog analysis and comparison of cellular fatty acids, this isolate was found to be different from the closely related species Azospirillum lipoferum, Azospirillum oryzae and Azospirillum brasilense. On the basis of these results, a novel species is proposed for this nitrogen-fixing strain. The name Azospirillum canadense sp. nov. is suggested with the type strain DS2(T) (=NCCB 100108(T)=LMG 23617(T)).

  4. Electrophysical characteristics of Azospirillum brasilense Sp245 during interaction with antibodies to various cell surface epitopes.

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    Guliy, Olga I; Matora, Larisa Y; Burygin, Gennady L; Dykman, Lev A; Ostudin, Nikolai A; Bunin, Viktor D; Ignatov, Vladimir V; Ignatov, Oleg V

    2007-11-15

    This work was undertaken to examine the electrooptical characteristics of cells of Azospirillum brasilense Sp245 during their interaction with antibodies developed to various cell surface epitopes. We used the dependences of the cell suspension optical density changes induced by electroorientation on the orienting field frequency (740, 1000, 1450, 2000, and 2800kHz). Cell interactions with homologous strain-specific antibodies to the A. brasilense Sp245 O antigen and with homologous antibodies to whole bacterial cells brought about considerable changes in the electrooptical properties of the bacterial suspension. When genus-specific antibodies to the flagellin of the Azospirillum sheathed flagellum and antibodies to the serologically distinct O antigen of A. brasilense Sp7 were included in the A. brasilense Sp245 suspension, the changes caused in the electrooptical signal were slight and had values close to those for the above changes. These findings agree well with the immunochemical characteristics of the Azospirillum O antigens and with the data on the topographical distribution of the Azospirillum major cell surface antigens. The obtained results can serve as a basis for the development of a rapid test for the intraspecies detection of microorganisms.

  5. KARAKTERISASI SIFAT-SIFAT BIOKIMIA EKSTRAK KASAR LIPASE EKSTRASELULER BAKTERI Azospirillum sp.PRD1

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    Santi Nur Handayani; Puji Lestari; Oedjijono; Tri Joko Raharjo; Sabirin Matsjeh

    2011-01-01

    Enzim lipase mempunyai peranan penting dalam katalis berbagai reaksi industri satu diantaranya pembuatan flavor melalui reaksi esterifikasi. Lipase adalah biokatalis yang berperan besar dalam aplikasi bioteknologi, seperti dalam sintesis biopolimer, biodiesel, produksi obat, dan produksi flavor. Peningkatan penggunaan lipase untuk industri mendorong dilakukan penelitian untuk mendapatkan sumber-sumber lipase baru. Sumber lipase yang potensial salah satunya adalah bakteri Azospirillum sp.PRD1 ...

  6. Azospirillum fermentarium sp. nov., a nitrogen-fixing species isolated from a fermenter.

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    Lin, Shih-Yao; Liu, You-Cheng; Hameed, Asif; Hsu, Yi-Han; Lai, Wei-An; Shen, Fo-Ting; Young, Chiu-Chung

    2013-10-01

    An aerobic, Gram-stain-negative, spiral or rod-shaped, non-spore-forming, diazotrophic bacterium (strain CC-LY743(T)) was isolated from a fermentative tank in Taiwan. Strain CC-LY743(T) was able to grow at 20-37 °C and pH 6.0-8.0 and tolerated up to 3.0 % (w/v) NaCl. It was positive for nitrogen fixation, with activity of 10.6 nmol ethylene h(-1). 16S rRNA gene sequence analysis of strain CC-LY743(T) showed highest similarity to Azospirillum picis DSM 19922(T) (96.1 %), Azospirillum oryzae JCM 21588(T) (96.0 %) and Azospirillum rugosum DSM 19657(T) (96.0 %) and lower similarity (Azospirillum species. Highest nifH gene sequence similarities were obtained with Azospirillum brasilense BCRC 12270(T) (92.0 %), Azospirillum formosense BCRC 80273(T) (92.3 %) and A. rugosum DSM 19657(T) (91.8 %). It was positive in the rapid identification by a genus-specific primer set. The predominant quinone system was ubiquinone 10 (Q-10) and the DNA G+C content was 69.6±0.1 mol%. The major fatty acids found in strain CC-LY743(T) were n-C16 : 0, C19 : 0 cyclo ω8c, C14 : 0 3-OH/C16 : 1 iso I, C16 : 1ω7c/C16 : 1ω6c and C18 : 1ω7c/C18 : 1ω6c. Based on its phylogenetic, phenotypic and chemotaxonomic features, strain CC-LY743(T) is considered to represent a novel species within the genus Azospirillum for which the name Azospirillum fermentarium sp. nov. is proposed. The type strain is CC-LY743(T) ( = BCRC 80505(T) = JCM 18688(T) = LMG 27264(T)).

  7. Azospirillum doebereinerae sp. nov., a nitrogen-fixing bacterium associated with the C4-grass Miscanthus.

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    Eckert, B; Weber, O B; Kirchhof, G; Halbritter, A; Stoffels, M; Hartmann, A

    2001-01-01

    A new group of nitrogen-fixing Azospirillum sp. bacteria was isolated from the roots of the C4-gramineous plant Miscanthus. Polyphasic taxonomy was performed, including auxanography using API galleries, physiological tests and 16S rRNA sequence comparison. The ability of the isolates to fix dinitrogen was evaluated by amplification of the nifD gene, immunodetection of the dinitrogenase reductase and acetylene-reduction assay. On the basis of these results, the nitrogen-fixing isolates represent a new species within the genus Azospirillum. Its closest phylogenetic neighbours, as deduced by 16S rDNA-based analysis, are Azospirillum lipoferum, Azospirillum largimobile and Azospirillum brasilense with 96.6, 96.6 and 95.9% sequence similarity, respectively. Two 16S rRNA-targeting oligonucleotide probes were developed which differentiate the new species from the other Azospirillum species by whole-cell fluorescence hybridization. Strains of the new species are curved rods or S-shaped, 1.0-1.5 microm in width and 2,0-3.0 microm in length, Gram-negative and motile with a single polar flagellum. Optimum growth occurs at 30 degrees C and at pH values between 6.0 and 7.0. No growth takes place at 37 degrees C. They have a respiratory type of metabolism, grow well on arabinose, D-fructose, gluconate, glucose, glycerol, malate, mannitol and sorbitol. They differ from A. largimobile and A. lipoferum by their inability to use N-acetylglucosamine and D-ribose, from A. lipoferum by their ability to grow without biotin supplementation and from A. brasilense by their growth with D-mannitol and D-sorbitol as sole carbon sources. Nitrogen fixation occurs in microaerobic nitrogen-limited conditions. For this species, the name Azospirillum doebereinerae sp. nov. is suggested, with strain GSF71T as the type strain (= DSM 13131T; reference strain Ma4 = DSM 13400). Its G+C content is 70.7 mol%.

  8. [Biofilm Formation by the Nonflagellated flhB1 Mutant of Azospirillum brasilense Sp245].

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    Shelud'ko, A V; Filip'echeva, Yu A; Shumiliva, E M; Khlebtsov, B N; Burov, A M; Petrova, L P; Katsy, E I

    2015-01-01

    Azospirillum brasilense Sp245 with mixed flagellation are able to form biofilms on various surfaces. A nonflagellated mutant of this strain with inactivated chromosomal copy of the flhB gene (flhB1) was shown to exhibit specific traits at the later stages of biofilm formation on a hydrophilic (glass) surface. Mature biofilms of the flhB1::Omegon-Km mutant Sp245.1063 were considerably thinner than those of the parent strain Sp245. The biofilms of the mutant were more susceptible to the forces of hydrodynamic shear. A. brasilense Sp245 cells in biofilms were not found to possess lateral flagella. Cells with polar flagella were, however, revealed by atomic force microscopy of mature native biofilms of strain Sp245. Preservation of a polar flagellum (probably nonmotile) on the cells of A. brasilense Sp245 may enhance the biofilm stability.

  9. Azospirillum IV

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    Klingmuller, W.

    1988-01-01

    This book's contents include: Advances in the genetics of Azospirillum brasilense Sp7: Use of Tn5 mutagenesis for gene mapping and identification; Characterization of DNA segments adjacent to the nifHDK genes of Azospirillum brasilense by Sp7 Tn5 site-directed mutagenesis; Selection at the chemostat of Azospirillum brasilense Cd N/sub 2/-fixing at high O/sub 2/ pressure. Root hair deformation induced on maize and medicago by an Azospirillum transconjugant containing a Rhizobium meliloti nodulation region. Azospirilla are bacteria that live in association with the roots of many grain crops. Since these bacteria bind molecular nitrogen from the air and excrete plant growth substances, interest has focussed on their potential to increase crop yields.

  10. [A STUDY OF THE ISOLATED BACTERIOPHAGE ΦAB-SP7 ADSORPTION ON THE CELL SURFACE OF THE AZOSPIRILLUM BRASILENSE SP7].

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    Guliy, O I; Karavaeva, O A; Velikov, V A; Sokolov, O I; Pavily, S A; Larionova, O S; Burov, A M; Ignatov, O V

    2016-01-01

    The bacteriophage ΦAb-Sp7 was isolated from the cells of the Azospirillum brasilense Sp7. The morphology, size of the gram-negative colonies, and range of lytic activity against other strains and species of the genus Azospirillum was tested. The isolated phage DNA was examined using electrophoretic and restriction analysis, and the size of the genome were established. The electron microscopy. resuIts show that the phage (capsid) has a strand-like form. The electron microscopy study of the bacteriophage ΦAb-Sp7 adsorption on the A. brasilense Sp7 bacterial surface was performed.

  11. Structural studies of the polysaccharides from the lipopolysaccharides of Azospirillum brasilense Sp246 and SpBr14.

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    Sigida, Elena N; Fedonenko, Yuliya P; Shashkov, Alexander S; Grinev, Vyacheslav S; Zdorovenko, Evelina L; Konnova, Svetlana A; Ignatov, Vladimir V; Knirel, Yuriy A

    2014-10-29

    Lipopolysaccharides from closely related Azospirillum brasilense strains, Sp246 and SpBr14, were obtained by phenol-water extraction. Mild acid hydrolysis of the lipopolysaccharides followed by GPC on Sephadex G-50 resulted in polysaccharide mixtures. On the basis of sugar and methylation analyses, Smith degradation and (1)H and (13)C NMR spectroscopy data, it was concluded that both bacteria possess the same two distinct polysaccharides having structures 1 and 2: [structure: see text]. Structure 1 has been reported earlier for a polysaccharide of A. brasilense 54 [Fedonenko et al., 2011] whereas to our knowledge structure 2 has not been hitherto found in bacterial polysaccharides.

  12. [Isolation and purification of Mn-peroxidase from Azospirillum brasilense Sp245].

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    Kupriashina, M A; Selivanov, N Iu; Nikitina, V E

    2012-01-01

    Homogenous Mn-peroxidase of a 26-fold purity grade was isolated from a culture of Azospirillum brasilense Sp245 cultivated on a medium containing 0.1 mM pyrocatechol. The molecular weight of the enzyme is 43 kD as revealed by electrophoresis in SDS-PAAG. It was shown that the use of pyrocatechol and 2,2'-azino-bis(3-ethylbenzotiazoline-6-sulfonate) at concentrations of 0.1 and I mM as inductors increased the Mn-peroxidase activity by a factor of 3.

  13. Proline and Abscisic Acid Content in Droughted Corn Plant Inoculated with Azospirillum sp. and Arbuscular Mycorrhizae Fungi

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    NOVRI YOULA KANDOWANGKO

    2009-03-01

    Full Text Available Plants that undergo drought stress perform a physiological response such as accumulation of proline in the leaves and increased content abscisic acid. A research was conducted to study proline and abscisic acid (ABA content on drought-stressed corn plant with Azospirillum sp. and arbuscular mycorrhizae fungi (AMF inoculated at inceptisol soil from Bogor, West Java. The experiments were carried out in a green house from June up to September 2003, using a factorial randomized block design. In pot experiments, two factors were assigned, i.e. inoculation with Azospirillum (0, 0.50, 1.00, 1.50 ml/pot and inoculation with AMF Glomus manihotis (0, 12.50, 25.00, 37.50 g/pot. The plants were observed during tasseling up to seed filling periods. Results of experiments showed that the interaction between Azospirillum sp. and AMF was synergistically increased proline, however it decreased ABA.

  14. Preparation of miniantibodies to Azospirillum brasilense Sp245 surface antigens and their use for bacterial detection.

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    Dykman, Lev A; Staroverov, Sergei A; Guliy, Olga I; Ignatov, Oleg V; Fomin, Alexander S; Vidyasheva, Irina V; Karavaeva, Olga A; Bunin, Viktor D; Burygin, Gennady L

    2012-01-01

    This article reports the first preparation of miniantibodies to Azospirillum brasilense Sp245 surface antigens by using a combinatorial phage library of sheep antibodies. The prepared phage antibodies were used for the first time for lipopolysaccharide and flagellin detection by dot assay, electro-optical analysis of cell suspensions, and transmission electron microscopy. Interaction of A. brasilense Sp245 with antilipopolysaccharide and antiflagellin phage-displayed miniantibodies caused the magnitude of the electro-optical signal to change considerably. The electro-optical results were in good agreement with the electron microscopic data. This is the first reported possibility of employing phage-displayed miniantibodies in bacterial detection aided by electro-optical analysis of cell suspensions.

  15. Plant root transcriptome profiling reveals a strain-dependent response during Azospirillum-rice cooperation

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    Benoît eDrogue

    2014-11-01

    Full Text Available Cooperation involving Plant Growth-Promoting Rhizobacteria results in improvements of plant growth and health. While pathogenic and symbiotic interactions are known to induce transcriptional changes for genes related to plant defence and development, little is known about the impact of phytostimulating rhizobacteria on plant gene expression. This study aims at identifying genes significantly regulated in rice roots upon Azospirillum inoculation, considering possible favored interaction between a strain and its original host cultivar. Genome-wide analyses of Oryza sativa japonica cultivars Cigalon and Nipponbare were performed, by using microarrays, seven days post inoculation with A. lipoferum 4B (isolated from Cigalon or Azospirillum sp. B510 (isolated from Nipponbare and compared to the respective non-inoculated condition. A total of 7,384 genes were significantly regulated, which represent about 16 % of total rice genes. A set of 34 genes is regulated by both Azospirillum strains in both cultivars, including a gene orthologous to PR10 of Brachypodium, and these could represent plant markers of Azospirillum-rice interactions. The results highlight a strain-dependent response of rice, with 83 % of the differentially expressed genes being classified as combination-specific. Whatever the combination, most of the differentially expressed genes are involved in primary metabolism, transport, regulation of transcription and protein fate. When considering genes involved in response to stress and plant defence, it appears that strain B510, a strain displaying endophytic properties, leads to the repression of a wider set of genes than strain 4B. Individual genotypic variations could be the most important driving force of rice roots gene expression upon Azospirillum inoculation. Strain-dependent transcriptional changes observed for genes related to auxin and ethylene signalling highlight the complexity of hormone signalling networks in the Azospirillum

  16. A hybrid two-component system protein from Azospirillum brasilense Sp7 was involved in chemotaxis.

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    Cui, Yanhua; Tu, Ran; Wu, Lixian; Hong, Yuanyuan; Chen, Sanfeng

    2011-09-20

    We here report the sequence and functional analysis of org35 of Azospirillum brasilense Sp7, which was originally identified to be able to interact with NifA in yeast-two-hybrid system. The org35 encodes a hybrid two-component system protein, including N-terminal PAS domains, a histidine kinase (HPK) domain and a response regulator (RR) domain in C-terminal. To determine the function of the Org35, a deletion-insertion mutant in PAS domain [named Sp7353] and a complemental strain Sp7353C were constructed. The mutant had reduced chemotaxis ability compared to that of wild-type, and the complemental strain was similar to the wild-type strain. These data suggested that the A. brasilense org35 played a key role in chemotaxis. Variants containing different domains of the org35 were expressed, and the functions of these domains were studied in vitro. Phosphorylation assays in vitro demonstrated that the HPK domain of Org35 possessed the autokinase activity and that the phosphorylated HPK was able to transfer phosphate groups to the RR domain. The result indicated Org35 was a phosphorylation-communicating protein.

  17. Glycogen phosphorylase is involved in stress endurance and biofilm formation in Azospirillum brasilense Sp7.

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    Lerner, Anat; Castro-Sowinski, Susana; Lerner, Hadas; Okon, Yaacov; Burdman, Saul

    2009-11-01

    Here we report the identification of a glycogen phosphorylase (glgP) gene in the plant growth-promoting rhizobacterium Azospirillum brasilense, Sp7, and the characterization of a glgP marker exchange mutant of this strain. The glgP mutant showed a twofold reduction of glycogen phosphorylase activity and an increased glycogen accumulation as compared with wild-type Sp7, indicating that the identified gene indeed encodes a protein with glycogen phosphorylase activity. Interestingly, the glgP mutant had higher survival rates than the wild type after exposure to starvation, desiccation and osmotic pressure. The mutant was shown to be compromised in its biofilm formation ability. Analysis of the exopolysaccharide sugar composition of the glgP mutant revealed a decrease in the amount of glucose, accompanied by increases in rhamnose, fucose and ribose, as compared with the Sp7 exopolysaccharide. To the best of our knowledge, this is the first study that demonstrates GlgP activity in A. brasilense, and shows that glycogen accumulation may play an important role in the stress endurance of this bacterium.

  18. Co2 + interaction with Azospirillum brasilense Sp7 cells: a 57Co emission Mössbauer spectroscopic study

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    Kamnev, Alexander A.; Tugarova, Anna V.; Biró, Borbála; Kovács, Krisztina; Homonnay, Zoltán; Kuzmann, Ernő; Vértes, Attila

    2012-03-01

    Preliminary 57Co emission Mössbauer spectroscopic data were obtained for the soil bacterium Azospirillum brasilense Sp7 ( T = 80 K) in frozen 57Co2 + -containing suspensions and in their dried residues. The Mössbauer parameters were compared with those for A. brasilense strain Sp245 differing from strain Sp7 by ecological behaviour. Live cells of both strains showed metabolic transformations of 57Co2 + within an hour. Differences in the parameters observed for the two strains under similar conditions suggest dissimilarities in their metabolic response to Co2 + .

  19. Co{sup 2 + } interaction with Azospirillum brasilense Sp7 cells: a {sup 57}Co emission Moessbauer spectroscopic study

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    Kamnev, Alexander A.; Tugarova, Anna V. [Russian Academy of Sciences, Institute of Biochemistry and Physiology of Plants and Microorganisms (Russian Federation); Biro, Borbala [Hungarian Academy of Sciences, Research Institute for Soil Science and Agricultural Chemistry (Hungary); Kovacs, Krisztina, E-mail: kkriszti@chem.elte.hu; Homonnay, Zoltan; Kuzmann, Erno; Vertes, Attila [Eoetvoes Lorand University, Institute of Chemistry (Hungary)

    2012-03-15

    Preliminary {sup 57}Co emission Moessbauer spectroscopic data were obtained for the soil bacterium Azospirillum brasilense Sp7 (T = 80 K) in frozen {sup 57}Co{sup 2 + }-containing suspensions and in their dried residues. The Moessbauer parameters were compared with those for A. brasilense strain Sp245 differing from strain Sp7 by ecological behaviour. Live cells of both strains showed metabolic transformations of {sup 57}Co{sup 2 + } within an hour. Differences in the parameters observed for the two strains under similar conditions suggest dissimilarities in their metabolic response to Co{sup 2 + }.

  20. Structural studies of the O-specific polysaccharide(s) from the lipopolysaccharide of Azospirillum brasilense type strain Sp7.

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    Sigida, Elena N; Fedonenko, Yuliya P; Shashkov, Alexander S; Zdorovenko, Evelina L; Konnova, Svetlana A; Ignatov, Vladimir V; Knirel, Yuriy A

    2013-10-18

    Lipopolysaccharide was obtained by phenol-water extraction from dried bacterial cells of Azospirillum brasilense type strain Sp7. Mild acid hydrolysis of the lipopolysaccharide followed by GPC on Sephadex G-50 resulted in a polysaccharide mixture, which was studied by composition and methylation analyses, Smith degradation and (1)H and (13)C NMR spectroscopy. The following polysaccharide structures were established, where italics indicate a non-stoichiometric (∼40%) 2-O-methylation of l-rhamnose.

  1. PEMBUATAN DEKSTRIN DARI PATI UBI KAYU MENGGUNAKAN KATALIS AMILASE HASIL FRAKSINASI DARI Azospirillum sp. JG3

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    Zusfahair

    2012-05-01

    Full Text Available Amilase merupakan salah satu enzim potensial dalam proses industri. Amilase dapat diperoleh dari bakteri Azopsirillum sp. JG3. Amilase ini dapat dimanfaatkan untuk hidrolisis pati ubi kayu pada pembuatan dekstrin. Dekstrin memiliki peran yang cukup penting dalam industri seperti pembuatan roti, makanan bayi dan bahan penyalut lapis tipis tablet. Penelitian ini bertujuan untuk mengetahui karakterisasi biokimiawi amilase hasil fraksinasi dari Azospirillum sp. JG3 serta potensinya dalam pembuatan dekstrin. Tahap penelitian ini dimulai dengan memproduksi enzim yang dilakukan dengan cara menumbuhkan inokulum ke dalam medium produksi selama 30 jam kemudian diekstraksi dengan sentrifugasi sehingga diperoleh ekstrak kasar. Ekstrak kasar amilase kemudian difraksinasi secara bertahap (15%, 30%, 45% dan 60% dengan menggunakan ammonium sulfat dan didialisis. Fraksi yang diperoleh diukur aktivitas, volume dan kadar proteinnya. Fraksi dengan aktivitas spesifik tertinggi dikarakterisasi dan digunakan untuk membuat dekstrin dari pati ubi kayu. Dekstrin pati ubi kayu yang diperoleh dikarakterisasi berupa rendemen, kadar air, kadar abu dan dextrose equivalen. Hasil penelitian menunjukkan bahwa fraksi hasil dialisis 45% (FHD 45% menghasilkan aktivitas dan aktivitas spesifik tertinggi berturut-turut sebesar 11,659 U/mL dan 7,319 U/mg. Aktivitas amilase optimum pada suhu 30°C, pH 7 dan konsentrasi substrat 4%. Dekstrin yang diperoleh memiliki rendemen 95,14, kadar air 3,411%, kadar abu 0,209% dan dextrose equivalen 13,4.

  2. Genome Sequence of Azospirillum brasilense CBG497 and Comparative Analyses of Azospirillum Core and Accessory Genomes provide Insight into Niche Adaptation

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    Victor González

    2012-09-01

    Full Text Available Bacteria of the genus Azospirillum colonize roots of important cereals and grasses, and promote plant growth by several mechanisms, notably phytohormone synthesis. The genomes of several Azospirillum strains belonging to different species, isolated from various host plants and locations, were recently sequenced and published. In this study, an additional genome of an A. brasilense strain, isolated from maize grown on an alkaline soil in the northeast of Mexico, strain CBG497, was obtained. Comparative genomic analyses were performed on this new genome and three other genomes (A. brasilense Sp245, A. lipoferum 4B and Azospirillum sp. B510. The Azospirillum core genome was established and consists of 2,328 proteins, representing between 30% to 38% of the total encoded proteins within a genome. It is mainly chromosomally-encoded and contains 74% of genes of ancestral origin shared with some aquatic relatives. The non-ancestral part of the core genome is enriched in genes involved in signal transduction, in transport and in metabolism of carbohydrates and amino-acids, and in surface properties features linked to adaptation in fluctuating environments, such as soil and rhizosphere. Many genes involved in colonization of plant roots, plant-growth promotion (such as those involved in phytohormone biosynthesis, and properties involved in rhizosphere adaptation (such as catabolism of phenolic compounds, uptake of iron are restricted to a particular strain and/or species, strongly suggesting niche-specific adaptation.

  3. AMPLIFICATION OF AZOSPIRILLUM SP. JG3 GLPD GENE FRAGMENT USING DEGENERATE PRIMERS GENERATED BY WEB-BASED TOOLS

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    Stalis Norma Ethica

    2013-12-01

    Full Text Available Primaclade and In Silico web-based tools were used as a strategy to obtain the correct-size PCR amplicon targeting a fragment of gene encoding glycerol-3-phosphate dehydrogenase (glpD of Azospirillum sp. JG3. The bacterial strains are soil, Gram-negative PGPR (Plant-Growth Promoting Rhizobacteria isolated from an agricultural land in Purwokerto, Central Java, Indonesia, which have ability to produce several commercial enzymes. The aim is to obtain a pair of reliable degenerate primers from a limited number of glpD sequences from other Azospirilla retrieved in GenBank using bioinformatics approach. We demonstrated degenerate primer design that led to successful PCR amplification corresponding to the targeted DNA fragment. Homology analysis showed that the obtained DNA fragment is 61% and 99% similar to sn-glycerol-3-phosphate dehydrogenase genes of Azospirillum brasilense and Stenotrophomonas maltophili respectively.

  4. Identification of an O-linked repetitive glycan chain of the polar flagellum flagellin of Azospirillum brasilense Sp7.

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    Belyakov, Alexei Ye; Burygin, Gennady L; Arbatsky, Nikolai P; Shashkov, Alexander S; Selivanov, Nikolai Yu; Matora, Larisa Yu; Knirel, Yuriy A; Shchyogolev, Sergei Yu

    2012-11-01

    This is the first report to have identified an O-linked repetitive glycan in bacterial flagellin, a structural protein of the flagellum. Studies by sugar analysis, Smith degradation, (1)H and (13)C NMR spectroscopy, and mass spectrometry showed that the glycan chains of the polar flagellum flagellin of the plant-growth-promoting rhizobacterium Azospirillum brasilense Sp7 are represented by a polysaccharide with a molecular mass of 7.7 kDa, which has a branched tetrasaccharide repeating unit of the following structure:

  5. A cytochrome cbb3 (cytochrome c) terminal oxidase in Azospirillum brasilense Sp7 supports microaerobic growth.

    Science.gov (United States)

    Marchal, K; Sun, J; Keijers, V; Haaker, H; Vanderleyden, J

    1998-11-01

    Spectral analysis indicated the presence of a cytochrome cbb3 oxidase under microaerobic conditions in Azospirillum brasilense Sp7 cells. The corresponding genes (cytNOQP) were isolated by using PCR. These genes are organized in an operon, preceded by a putative anaerobox. The phenotype of an A. brasilense cytN mutant was analyzed. Under aerobic conditions, the specific growth rate during exponential phase (mu(e)) of the A. brasilense cytN mutant was comparable to the wild-type specific growth rate (m(e) of approximately 0.2 h-1). In microaerobic NH4+-supplemented conditions, the low respiration of the A. brasilense cytN mutant affected its specific growth rate (mu(e) of approximately 0.02 h-1) compared to the wild-type specific growth rate (mu(e) of approximately 0.2 h-1). Under nitrogen-fixing conditions, both the growth rates and respiration of the wild type were significantly diminished in comparison to those under NH4+-supplemented conditions. Differences in growth rates and respiration between the wild type and the A. brasilense cytN mutant were less pronounced under these nitrogen-fixing conditions (mu(e) of approximately 0.03 h-1 for the wild type and 0.02 h-1 for the A. brasilense cytN mutant). The nitrogen-fixing capacity of the A. brasilense cytN mutant was still approximately 80% of that determined for the wild-type strain. This leads to the conclusion that the A. brasilense cytochrome cbb3 oxidase is required under microaerobic conditions, when a high respiration rate is needed, but that under nitrogen-fixing conditions the respiration rate does not seem to be a growth-limiting factor.

  6. Convergent synthesis of a tetrasaccharide repeating unit of the O-specific polysaccharide from the cell wall lipopolysaccharide of Azospirillum brasilense strain Sp7

    Directory of Open Access Journals (Sweden)

    Pintu Kumar Mandal

    2014-01-01

    Full Text Available A straightforward convergent synthesis has been carried out for the tetrasaccharide repeating unit of the O-specific cell wall lipopolysaccharide of the strain Sp7 of Azospirillum brasilense. The target tetrasaccharide has been synthesized from suitably protected monosaccharide intermediates in 42% overall yield in seven steps by using a [2 + 2] block glycosylation approach.

  7. Convergent synthesis of a tetrasaccharide repeating unit of the O-specific polysaccharide from the cell wall lipopolysaccharide of Azospirillum brasilense strain Sp7

    OpenAIRE

    Mandal, Pintu Kumar; Dhara, Debashis; Misra, Anup Kumar

    2014-01-01

    A straightforward convergent synthesis has been carried out for the tetrasaccharide repeating unit of the O-specific cell wall lipopolysaccharide of the strain Sp7 of Azospirillum brasilense. The target tetrasaccharide has been synthesized from suitably protected monosaccharide intermediates in 42% overall yield in seven steps by using a [2 + 2] block glycosylation approach.

  8. Effect of nitrogen supply and Azospirillum brasilense Sp-248 on the response of wheat to seawater irrigation.

    Science.gov (United States)

    Alamri, Saad A; Mostafa, Yasser S

    2009-10-01

    Response of wheat to Azospirillum brasilense Sp-248 inoculation with different N-fertilizer levels using seawater irrigation was investigated. All inoculated treatments increased plant height, shoot and root dry weight, and tiller number in compared with uninoculated treatments. Yield parameters measured were also increased due to the inoculation. In terms of the effect of saline irrigation, there were no significant differences in growth and yield parameters in plants treated with tap water and others irrigated with 8.0% seawater concentration. This would indicate a relatively high tolerance of A. brasilense to saline irrigation and its ability to reduce the deleterious effects of saline on growth by increasing the plant's adaptation. However, increasing the seawater concentration in the irrigation water to 16.0% significantly decreased all tested parameters. Inoculation treatments generally increased NPKCa contents and decreased sodium ratio of the grains in compared with the uninoculated treatments. Overall results clearly revealed that the Azospirillum inoculation saved about 20 units of N-fertilizer and that saving was made economically feasible by decreasing the chemical fertilizers needed, improving the nitrogen content and counteracting the effects of salinity.

  9. Effect of genomic rearrangement on heavy metal tolerance in the plant-growth-promoting rhizobacterium Azospirillum brasilense Sp245.

    Science.gov (United States)

    Shelud'ko, Andrei V; Varshalomidze, Olga E; Petrova, Lilia P; Katsy, Elena I

    2012-01-01

    A derivative of Azospirillum brasilense Sp245, Sp245.5, which spontaneously lost 85 and 120 MDa replicons upon the formation of a new megaplasmid, has been shown to produce a novel lipopolysaccharide and to lose Calcofluor-binding polysaccharides. As compared to Sp245, the derivative displays notably increased heavy metal tolerance. The phenotypes of Sp245 and Sp245.5 are characterized by the following minimal inhibitory concentrations (MICs) of heavy metals: 0.5 and 0.9 μmol l(-1) of Ag(+), 0.4 and 0.7 mmol l(-1) of Co(2+), 0.9 and 4.7 mmol l(-1) of Cu(2+), and 3.1 and 11.5 mmol l(-1) of Zn(2+), respectively. In Sp245, in the presence of a nonlethal concentration (0.625 μmol l(-1)) of the efflux pump inhibitor carbonyl cyanide m-chlorophenylhydrazone (CCCP), the MIC of cobalt, copper, and zinc drop 1.3- to 1.6-fold, but the low tolerance to silver is unaffected. In Sp245.5, CCCP does not affect cobalt tolerance, suppresses tolerance to copper and silver to the wild-type levels, and causes a 1.4-fold decrease in resistance to zinc. Therefore, significant elevation of heavy metal tolerance in Sp245.5 seems caused by the induction/overexpression of the proton-dependent efflux of certain metal ions. The novel cell surface and other unknown factors could also be responsible for the increased tolerance of A. brasilense Sp245.5 to heavy metals.

  10. Fourier transform Raman spectroscopic characterisation of cells of the plant-associated soil bacterium Azospirillum brasilense Sp7

    Science.gov (United States)

    Kamnev, A. A.; Tarantilis, P. A.; Antonyuk, L. P.; Bespalova, L. A.; Polissiou, M. G.; Colina, M.; Gardiner, P. H. E.; Ignatov, V. V.

    2001-05-01

    Structural and compositional features of bacterial cell samples and of lipopolysaccharide-protein complex isolated from the cell surface of the plant-growth-promoting rhizobacterium Azospirillum brasilense (wild-type strain Sp7) were characterised using Fourier transform (FT) Raman spectroscopy. The structural spectroscopic information obtained is analysed and considered together with analytical data on the content of metal cations (Co 2+, Cu 2+ and Zn 2+) in the bacterial cells grown in a standard medium as well as in the presence of each of the cations (0.2 mM). The latter, being taken up by bacterial cells from the culture medium in significant amounts, were shown to induce certain metabolic changes in the bacterium revealed in FT-Raman spectra, which is discussed from the viewpoint of bacterial response to environmental stresses.

  11. Mössbauer spectroscopic study of 57Fe metabolic transformations in the rhizobacterium Azospirillum brasilense Sp245

    Science.gov (United States)

    Kamnev, Alexander A.; Tugarova, Anna V.; Kovács, Krisztina; Biró, Borbála; Homonnay, Zoltán; Kuzmann, Ernő

    2014-04-01

    Preliminary 57Fe transmission Mössbauer spectroscopic data were obtained for the first time for live cells of the plant-growth-promoting rhizobacterium Azospirillum brasilense (wild-type strain Sp245) grown aerobically with 57FeIII-nitrilotriacetate (NTA) complex as a sole source of iron. The results obtained have shown that live cells actively reduce part of the assimilated iron(III) to iron(II), the latter amounting up to 33 % of total cellular iron after 18 h of growth, and 48 % after additional 3 days of storage of the dense wet cell suspension in nutrient-free saline solution in air at room temperature (measured at 80 K). The cellular iron(II) was found to be represented by two quadrupole doublets of different high-spin forms, while the parameters of the cellular iron(III) were close to those typical for bacterioferritins.

  12. The Azospirillum brasilense Sp7 noeJ and noeL genes are involved in extracellular polysaccharide biosynthesis.

    Science.gov (United States)

    Lerner, Anat; Castro-Sowinski, Susana; Valverde, Angel; Lerner, Hadas; Dror, Rachel; Okon, Yaacov; Burdman, Saul

    2009-12-01

    Azospirillum brasilense is a plant root-colonizing bacterium that exerts beneficial effects on the growth of many agricultural crops. Extracellular polysaccharides of the bacterium play an important role in its interactions with plant roots. The pRhico plasmid of A. brasilense Sp7, also named p90, carries several genes involved in synthesis and export of cell surface polysaccharides. We generated two Sp7 mutants impaired in two pRhico-located genes, noeJ and noeL, encoding mannose-6-phosphate isomerase and GDP-mannose 4,6-dehydratase, respectively. Our results demonstrate that in A. brasilense Sp7, noeJ and noeL are involved in lipopolysaccharide and exopolysaccharide synthesis. noeJ and noeL mutant strains were significantly altered in their outer membrane and cytoplasmic/periplasmic protein profiles relative to the wild-type strain. Moreover, both noeJ and noeL mutations significantly affected the bacterial responses to several stresses and antimicrobial compounds. Disruption of noeL, but not noeJ, affected the ability of the A. brasilense Sp7 to form biofilms. The pleiotropic alterations observed in the mutants could be due, at least partially, to their altered lipopolysaccharides and exopolysaccharides relative to the wild-type.

  13. Afinidad y efecto de Azospirillum sp. en maíz

    OpenAIRE

    José Antonio Rangel-Lucio; María de las Nieves Rodríguez-Mendoza; Ronald Ferrera-Cerrato; Javier Zaragoza Castellanos-Ramos; Rosa María Ramírez-Gama; Estéfana Alvarado-Bárcenas

    2011-01-01

    El objetivo del presente trabajo fue determinar la afi nidad y efecto de cepas de Azospirillum en maíz. Este bioensayo se desarrolló en el estado de México, México, durante el ciclo primavera - verano del 2009. Para ello se colectó la raíz de maíz Palomero Toluqueño, Cacahuacintle, Cónico, Chalqueño y H-20, y de Teocintle, y después de aislar y purifi car las cepas sobresalientes por actividad nitrogenasa (N¿asa), se re-inocularon ascépticamente en las mismas variedades en estadío de plántula...

  14. [Genome Rearrangements in Azospirillum brasilense Sp7 with the Involvement of the Plasmid pRhico and the Prophage phiAb-Cd].

    Science.gov (United States)

    Katsy, E I; Petrova, L P

    2015-12-01

    Alphaproteobacteria of the species Azospirillum brasilense have a multicomponent genome that undergoes frequent spontaneous rearrangements, yielding changes in the plasmid profiles of strains. Specifically, variants (Cd, Sp7.K2, Sp7.1, Sp7.4, Sp7.8, etc.) of the type strainA. brasilense Sp7 that had lost a 115-MDa plasmid were previously selected. In many of them, the molecular weight of a 90-MDa plasmid (p90 or pRhico), which is a kind of "depot" for glycopolymer biosynthesis genes, increased. In this study, a collection of primers was designed to the plasmid pRhico and to the DNA of prophage phiAb-Cd integrated in it. The use ofthese primers in polymerase chain reactions allowed the detection of the probable excision of phiAb-Cd phage from the DNA of A. brasilense variants Sp7.4 and Sp7.8 and other alterations of the pRhico structure in A. brasilense strains Cd, Sp7.K2, and Sp7.8. The developed primers and PCR conditions may be recoin mended for primary analysis of spontaneous plasmid rearrangements in A. brasilense Sp7 and related strains.

  15. Synthesis of the tetrasaccharide repeating unit of the O-glycan from the polar flagellum flagellin of Azospirillum brasilense Sp7.

    Science.gov (United States)

    Pal, Kumar Bhaskar; Mukhopadhyay, Balaram

    2014-12-01

    Chemical synthesis of the tetrasaccharide repeating unit of the O-glycan from the polar flagellum flagellin of Azospirillum brasilense Sp7 in the form of its p-methoxyphenyl glycoside is reported. The required glycosidic linkages have been accomplished by activation of thioglycosides with N-iodosuccinimide in the presence of H2SO4-silica. H2SO4-silica was found to be an effective alternative to the classical acid promoters like TfOH or TMSOTf and it can lead to the formation of both 1,2-cis and 1,2-trans glycosidic linkages depending on the protecting group manipulation and control of the reaction condition.

  16. [The structure of the O-specific polysaccharide from a mutant of nitrogen-fixing rhizobacterium Azospirillum brasilense Sp245 with an altered plasmid content].

    Science.gov (United States)

    Fedonenko, Iu P; Katsy, E I; Petrova, L P; Boĭko, A S; Zdorovenko, E L; Kachala, V V; Shashkov, A S; Knirel', Iu A

    2010-01-01

    The rhizobacteria Azospirillum brasilense Sp245 produce antigenically different lipopolysaccharides LPSI and LPSII, both containing identical pentasaccharides built from D-rhamnose residues as the repeated chains of O-specific oligosaccharides (OPS). In this study, we report the structure of the OPS from A. brasilense LPSI(-)LPSII(-)-mutant Sp245.5, which spontaneously lost the p85 and p120 plasmids upon the formation of a new 300-MDa megaplasmid after the long-term storage of the bacteria in a rich medium. The repeating unit of the A. brasilense mutant Sp245.5 appeared to be a disaccharide consisting of residues of N-acetyl-D-galactosamine and N-acetyl-D-mannosaminuronic acid: [Formula: see text].

  17. Spontaneous Super-Swarming Derivatives of Azospirillum brasilense Sp245 have Different DNA Profiles and Behavior in the Presence of Various Nitrogen Sources.

    Science.gov (United States)

    Varshalomidze, Olga E; Petrova, Lilia P; Shelud'ko, Andrei V; Katsy, Elena I

    2012-12-01

    Azospirillum brasilense swims in liquid environments and swarms in semisolid media. Five variants of A. brasilense Sp245, Sp245.P1-Sp245.P5, which swarmed faster than Sp245 in a semisolid malate-salt medium, have been isolated. In Sp245.P1-Sp245.P4, a new megaplasmid was revealed instead of an indigenous 85-MDa plasmid (p85). By polymerase chain reactions (PCR) with primers to the segments of p85 important for proper bacterial motility/flagellation and for dissimilatory nitrite and NO reduction, that DNA of p85 was found retained by all the variants. In ERIC- and RAPD-PCR, microdiversity between the total DNAs of Sp245 and its variants was detected. Interstrain differences in growth characteristics in liquid peptone-succinate-salt medium with KNO3 or KNO2 and in KNO2 production/consumption were revealed. Although all the variants swam and swarmed faster than Sp245 in the medium supplemented with NH4Cl or KNO3, not all of them could do so in MPSS with KNO2.

  18. Convergent synthesis of a tetrasaccharide repeating unit of the O-specific polysaccharide from the cell wall lipopolysaccharide of Azospirillum brasilense strain Sp7

    OpenAIRE

    Pintu Kumar Mandal; Debashis Dhara; Anup Kumar Misra

    2014-01-01

    A straightforward convergent synthesis has been carried out for the tetrasaccharide repeating unit of the O-specific cell wall lipopolysaccharide of the strain Sp7 of Azospirillum brasilense. The target tetrasaccharide has been synthesized from suitably protected monosaccharide intermediates in 42% overall yield in seven steps by using a [2 + 2] block glycosylation approach.

  19. Study of the rhizobacterium Azospirillum brasilense Sp245 using Mössbauer spectroscopy with a high velocity resolution: Implication for the analysis of ferritin-like iron cores

    Science.gov (United States)

    Alenkina, I. V.; Oshtrakh, M. I.; Tugarova, A. V.; Biró, B.; Semionkin, V. A.; Kamnev, A. A.

    2014-09-01

    The results of a comparative study of two samples of the rhizobacterium Azospirillum brasilense (strain Sp245) prepared in different conditions and of human liver ferritin using Mössbauer spectroscopy with a high velocity resolution demonstrated the presence of ferritin-like iron (i.e. iron similar to that found in ferritin-like proteins) in the bacterium. Mössbauer spectra of these samples were fitted in two ways: as a rough approximation using a one quadrupole doublet fit (the homogeneous iron core model) and using a superposition of quadrupole doublets (the heterogeneous iron core model). Both results demonstrated differences in the Mössbauer parameters for mammalian ferritin and for bacterial ferritin-like iron. Moreover, some differences in the Mössbauer parameters were observed between the two samples of A. brasilense Sp245 related to the differences in their preparation conditions.

  20. Involvement of glnB, glnZ, and glnD genes in the regulation of poly-3-hydroxybutyrate biosynthesis by ammonia in Azospirillum brasilense Sp7.

    Science.gov (United States)

    Sun, Jun; Van Dommelen, Anne; Van Impe, Jan; Vanderleyden, Jozef

    2002-02-01

    The role of three key nitrogen regulatory genes, glnB (encoding the P(II) protein), glnZ (encoding the P(z) protein), and glnD (encoding the GlnD protein), in regulation of poly-3-hydroxybutyrate (PHB) biosynthesis by ammonia in Azospirillum brasilense Sp7 was investigated. It was observed that glnB glnZ and glnD mutants produce substantially higher amounts of PHB than the wild type produces during the active growth phase. glnB and glnZ mutants have PHB production phenotypes similar to that of the wild type. Our results indicate that the P(II)-P(z) system is apparently involved in nitrogen-dependent regulation of PHB biosynthesis in A. brasilense Sp7.

  1. Interaction between PII and NifA in Azospirillum brasilense Sp7

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The interaction between PII and NifA in A. brasilense Sp7 was investigated by using the yeast two-hybrid system. Our experimental results showed that PII directly interacted with the entire NifA protein and its N-terminal domain,but did not interact with the central domain and the C-terminal domain of NifA. No interaction happened if glnB coding for PII was frame-shift mutated. Pz, a homolog of PII, had no interation with NifA.

  2. Sequencing and promoter analysis of the nifENXorf3orf5fdxAnifQ operon from Azospirillum brasilense Sp7

    Directory of Open Access Journals (Sweden)

    Potrich D.P.

    2001-01-01

    Full Text Available A 40-kb DNA region containing the major cluster of nif genes has been isolated from the Azospirillum brasilense Sp7 genome. In this region three nif operons have been identified: nifHDKorf1Y, nifENXorf3orf5fdxAnifQ and orf2nifUSVorf4. The operons containing nifENX and nifUSV genes are separated from the structural nifHDKorf1Y operon by about 5 kb and 10 kb, respectively. The present study shows the sequence analysis of the 6045-bp DNA region containing the nifENX genes. The deduced amino acid sequences from the open reading frames were compared to the nif gene products of other diazotrophic bacteria and indicate the presence of seven ORFs, all reading in the same direction as that of the nifHDKorf1Y operon. Consensus sigma54 and NifA-binding sites are present only in the promoter region upstream of the nifE gene. This promoter is activated by NifA protein and is approximately two-times less active than the nifH promoter, as indicated by the ß-galactosidase assays. This result suggests the differential expression of the nif genes and their respective products in Azospirillum.

  3. A CheR/CheB fusion protein is involved in cyst cell development and chemotaxis in Azospirillum brasilense Sp7.

    Science.gov (United States)

    Wu, Lixian; Cui, Yanhua; Hong, Yuanyuan; Chen, Sanfeng

    2011-12-20

    We here report the sequence and functional analysis of cstB of Azospirillum brasilense Sp7. The predicted cstB contains C-terminal two PAS domains and N-terminal part which has similarity with CheB-CheR fusion protein. cstB mutants had reduced swarming ability compared to that of A. brasilense wild-type strain, implying that cstB was involved in chemotaxis in A. brasilense. A microscopic analysis revealed that cstB mutants developed mature cyst cells more quickly than wild type, indicating that cstB is involved in cyst formation. cstB mutants were affected in colony morphology and the production of exopolysaccharides (EPS) which are essential for A. brasilense cells to differentiate into cyst-like forms. These observations suggested that cstB was a multi-effector involved in cyst development and chemotaxis in A. brasilense.

  4. [Mutants of bacterium Azospirillum brasilense Sp245 with Omegon insertion in mmsB or fabG genes of lipid metabolism are defective in motility and flagellation].

    Science.gov (United States)

    Kovtunov, E A; Shelud'ko, A V; Chernyshova, M P; Petrova, L P; Katsy, E I

    2013-11-01

    Bacteria Azospirillum brasilense have mixed flagellation: in addition to the polar flagellum, numerous lateral flagella are formed in their cells on medium with increased density. Flagella determine the active swimming and swarming capacities of azospirilla. Using A. brasilense Sp245 as an example, we showed that the Omegon-Km artificial transposon insertion into the chromosomal gene for 3-hydroxyisobutyrate dehydrogenase (mmsB) was concurrent with the appearance of significant defects in the formation of polar flagella and with the paralysis of lateral flagella. The Sp245 mutant with the Omegon insertion into the plasmid AZOBR_p1-borne gene for 3-oxoacyl-[acyl-carrier protein]-reductase (fabG) showed the complete loss of flagella and the swarming capacity, as well as significant defects in polar flagellar assembly (though some cells are still motile in liquid medium). The viability of the A. brasilense Sp245 mutants with the Omegon insertion into the mmsB or fabG gene was not reduced. No considerable differences in the fatty acid composition of whole cell lipid extracts were found for the A. brasilense Sp245 strain and its mmsB and fabG mutants.

  5. Relationship between in vitro enhanced nitrogenase activity of an Azospirillum brasilense Sp7 mutant and its growth-promoting activities in situ.

    Science.gov (United States)

    de Campos, Samanta Bolzan; Roesch, Luiz Fernando Wurdig; Zanettini, Maria Helena Bodanese; Passaglia, Luciane Maria Pereira

    2006-07-01

    In this work, we further analyzed an Azospirillum brasilense Sp7 mutant (Sp7::Tn5-33) showing a pleiotrophic phenotype due to a Tn5 insertion into an open reading frame of 840 bp (orf280). The deduced amino acid sequence of this region has high similarity to a family of universal stress proteins. Because the most interesting property exhibited by the Sp7::Tn5-33 mutant was an enhanced in vitro nitrogen fixation activity, we addressed the question of whether it could benefit the host plant. We found that the increased nitrogenase activity at the free-living state of the mutant bacterium was correlated with an increased production of the nitrogenase reductase protein (NifH), in amounts approximately 1.5 times higher than the wild type. The mutant strain exhibited the same level of auxin production and the same colonization pattern of wheat roots as the wild type. We also observed that Sp7::Tn5-33 increased the total plant dry weight, although the N content did not differ significantly between wheat plants inoculated with mutant or wild-type strains.

  6. Assessing the efficacy of co-inoculation of wheat seedlings with the associative bacteria Paenibacillus polymyxa 1465 and Azospirillum brasilense Sp245.

    Science.gov (United States)

    Yegorenkova, Irina V; Tregubova, Kristina V; Burygin, Gennady L; Matora, Larisa Y; Ignatov, Vladimir V

    2016-03-01

    Co-inoculation of associative bacteria, which have high nitrogen-fixing activity, tolerance for environmental conditions, and the ability to compete with the natural microflora, is used widely to enhance the growth and yields of agricultural plants. We evaluated the ability of 2 co-inoculated plant-growth-promoting rhizobacteria, Paenibacillus polymyxa 1465 and Azospirillum brasilense Sp245, to colonize roots of wheat (Triticum aestivum L. 'Saratovskaya 29') seedlings, and we assessed the morphometric parameters of wheat early in its development. Analysis by ELISA with polyclonal antibodies raised against the exopolysaccharide of P. polymyxa 1465 and the lipopolysaccharide of A. brasilense Sp245 demonstrated that the root-colonizing activity of A. brasilense was higher when the bacterium was co-inoculated with P. polymyxa than when it was inoculated singly. Immunofluorescence microscopy with Alexa Fluor 532-labeled antibodies revealed sites of attachment of co-inoculated P. polymyxa and A. brasilense and showed that the 2 bacteria colonized similar regions of the roots. Co-inoculation exerted a negative effect on wheat seedling development, inhibiting root length by 17.6%, total root weight by 11%, and total shoot weight by 12%. Under certain conditions, dual inoculation of wheat may prove ineffective, apparently owing to the competition between the rhizobacteria for colonization sites on the plant roots. The findings from this study may aid in developing techniques for mixed bacterial inoculation of cultivated plants. PMID:26863134

  7. Assessing the efficacy of co-inoculation of wheat seedlings with the associative bacteria Paenibacillus polymyxa 1465 and Azospirillum brasilense Sp245.

    Science.gov (United States)

    Yegorenkova, Irina V; Tregubova, Kristina V; Burygin, Gennady L; Matora, Larisa Y; Ignatov, Vladimir V

    2016-03-01

    Co-inoculation of associative bacteria, which have high nitrogen-fixing activity, tolerance for environmental conditions, and the ability to compete with the natural microflora, is used widely to enhance the growth and yields of agricultural plants. We evaluated the ability of 2 co-inoculated plant-growth-promoting rhizobacteria, Paenibacillus polymyxa 1465 and Azospirillum brasilense Sp245, to colonize roots of wheat (Triticum aestivum L. 'Saratovskaya 29') seedlings, and we assessed the morphometric parameters of wheat early in its development. Analysis by ELISA with polyclonal antibodies raised against the exopolysaccharide of P. polymyxa 1465 and the lipopolysaccharide of A. brasilense Sp245 demonstrated that the root-colonizing activity of A. brasilense was higher when the bacterium was co-inoculated with P. polymyxa than when it was inoculated singly. Immunofluorescence microscopy with Alexa Fluor 532-labeled antibodies revealed sites of attachment of co-inoculated P. polymyxa and A. brasilense and showed that the 2 bacteria colonized similar regions of the roots. Co-inoculation exerted a negative effect on wheat seedling development, inhibiting root length by 17.6%, total root weight by 11%, and total shoot weight by 12%. Under certain conditions, dual inoculation of wheat may prove ineffective, apparently owing to the competition between the rhizobacteria for colonization sites on the plant roots. The findings from this study may aid in developing techniques for mixed bacterial inoculation of cultivated plants.

  8. Growth of quailbush in acidic, metalliferous desert mine tailings: effect of Azospirillum brasilense Sp6 on biomass production and rhizosphere community structure.

    Science.gov (United States)

    de-Bashan, Luz E; Hernandez, Juan-Pablo; Nelson, Karis N; Bashan, Yoav; Maier, Raina M

    2010-11-01

    Mine tailing deposits in semiarid and arid environments frequently remain devoid of vegetation due to the toxicity of the substrate and the absence of a diverse soil microbial community capable of supporting seed germination and plant growth. The contribution of the plant growth promoting bacterium (PGPB) Azospirillum brasilense Sp6 to the growth of quailbush in compost-amended, moderately acidic, high-metal content mine tailings using an irrigation-based reclamation strategy was examined along with its influence on the rhizosphere bacterial community. Sp6 inoculation resulted in a significant (2.2-fold) increase in plant biomass production. The data suggest that the inoculum successfully colonized the root surface and persisted throughout the 60-day experiment in both the rhizosphere, as demonstrated by excision and sequencing of the appropriate denaturing gradient gel electrophoresis (DGGE) band, and the rhizoplane, as indicated by fluorescent in situ hybridization of root surfaces. Changes in rhizosphere community structure in response to Sp6 inoculation were evaluated after 15, 30, and 60 days using DGGE analysis of 16S rRNA polymerase chain reaction amplicons. A comparison of DGGE profiles using canonical correspondence analysis revealed a significant treatment effect (Sp6-inoculated vs. uninoculated plants vs. unplanted) on bacterial community structure at 15, 30, and 60 days (p < 0.05). These data indicate that in an extremely stressed environment such as acid mine tailings, an inoculated plant growth promoting bacterium not only can persist and stimulate plant growth but also can directly or indirectly influence rhizobacterial community development.

  9. Growth of Quailbush in Acidic, Metalliferous Desert Mine Tailings: Effect of Azospirillum brasilense Sp6 on Biomass Production and Rhizosphere Community Structure

    Science.gov (United States)

    de-Bashan, Luz E.; Hernandez, Juan-Pablo; Nelson, Karis N.; Bashan, Yoav

    2010-01-01

    Mine tailing deposits in semiarid and arid environments frequently remain devoid of vegetation due to the toxicity of the substrate and the absence of a diverse soil microbial community capable of supporting seed germination and plant growth. The contribution of the plant growth promoting bacterium (PGPB) Azospirillum brasilense Sp6 to the growth of quailbush in compost-amended, moderately acidic, high-metal content mine tailings using an irrigation-based reclamation strategy was examined along with its influence on the rhizosphere bacterial community. Sp6 inoculation resulted in a significant (2.2-fold) increase in plant biomass production. The data suggest that the inoculum successfully colonized the root surface and persisted throughout the 60-day experiment in both the rhizosphere, as demonstrated by excision and sequencing of the appropriate denaturing gradient gel electrophoresis (DGGE) band, and the rhizoplane, as indicated by fluorescent in situ hybridization of root surfaces. Changes in rhizosphere community structure in response to Sp6 inoculation were evaluated after 15, 30, and 60 days using DGGE analysis of 16S rRNA polymerase chain reaction amplicons. A comparison of DGGE profiles using canonical correspondence analysis revealed a significant treatment effect (Sp6-inoculated vs. uninoculated plants vs. unplanted) on bacterial community structure at 15, 30, and 60 days (p<0.05). These data indicate that in an extremely stressed environment such as acid mine tailings, an inoculated plant growth promoting bacterium not only can persist and stimulate plant growth but also can directly or indirectly influence rhizobacterial community development. PMID:20632001

  10. A constitutively expressed pair of rpoE2-chrR2 in Azospirillum brasilense Sp7 is required for survival under antibiotic and oxidative stress.

    Science.gov (United States)

    Gupta, Namrata; Kumar, Santosh; Mishra, Mukti Nath; Tripathi, Anil Kumar

    2013-02-01

    Extracytoplasmic function (ECF) sigma factors (σ(E)) are known to bring about changes in gene expression to enable bacteria to adapt to different stresses. The Azospirillum brasilense Sp245 genome harbours nine genes encoding σ(E), of which two are adjacent to the genes encoding ChrR-type zinc-binding anti-sigma (ZAS) factors. We describe here the role and regulation of a new pair of rpoE-chrR, which was found in the genome of A. brasilense Sp7 in addition to the previously described rpoE-chrR pair (designated rpoE1-chrR1). The rpoE2-chrR2 pair is also cotranscribed, and their products show protein-protein interaction. The -10 and -35 promoter elements of rpoE2-chrR2 and rpoE1-chrR1 were similar but not identical. Unlike the promoter of rpoE1-chrR1, the rpoE2-chrR2 promoter was neither autoregulated nor induced by oxidative stress. Inactivation of chrR2 or overexpression of rpoE2 in A. brasilense Sp7 resulted in an overproduction of carotenoids. It also conferred resistance to oxidative stresses and antibiotics. By controlling the synthesis of carotenoids, initiation and elongation of translation, protein folding and purine biosynthesis, RpoE2 seems to play a crucial role in preventing and repairing the cellular damage caused by oxidative stress. Lack of autoregulation and constitutive expression of rpoE2-chrR2 suggest that RpoE2-ChrR2 may provide a rapid mechanism to cope with oxidative stress, wherein singlet oxygen ((1)O(2))-mediated dissociation of the RpoE2-ChrR2 complex might release RpoE2 to drive the expression of its target genes.

  11. Screening of the interacting proteins with NifA in Azospirillum brasilense Sp7 by the yeast two-hybrid system

    Institute of Scientific and Technical Information of China (English)

    CHEN Sanfeng; GUAN Yu; TU Ran; SUN Wengai; LI Jilun

    2005-01-01

    NifA in Azospirillum brasilense plays a key role in regulating the synthesis and activity of nitrogenase in response to ammonia and oxygen available. In this work we used the yeast two-hybrid system to identify the proteins that interact with NifA. The nifA gene was fused to the yeast two-hybrid vector pGBD-C2, and three A. brasilense Sp7 genomic libraries for use in yeast two-hybrid studies were constructed. Screening of the libraries identified four clones encoding proteins that interact with NifA. The confirmation of the interactions of each gene product of the four clones and NifA were carried out by exchanging the vectors for nifA and the four clones and by mutageneses of the four clones with shift reading frame experiments in yeast two-hybrid studies. DNA sequence analyses showed that two clones encode proteins containing PAS domains that play an important role in signal transduction. One clone has high similarity with the fhuE gene of Escherichia coli, whose gene product is involved in iron uptake and transportation, and the other clone encodes an unknown protein.

  12. Fourier transform infrared spectroscopic characterisation of heavy metal-induced metabolic changes in the plant-associated soil bacterium Azospirillum brasilense Sp7

    Science.gov (United States)

    Kamnev, A. A.; Antonyuk, L. P.; Tugarova, A. V.; Tarantilis, P. A.; Polissiou, M. G.; Gardiner, P. H. E.

    2002-06-01

    Structural and compositional features of whole cells of the plant-growth-promoting rhizobacterium Azospirillum brasilense Sp7 under standard and heavy metal-stressed conditions are analysed using Fourier transform infrared (FTIR) spectroscopy and compared with the FT-Raman spectroscopic data obtained previously [J. Mol. Struct. 563-564 (2001) 199]. The structural spectroscopic information is considered together with inductively coupled plasma-mass spectrometric (ICP-MS) analytical data on the content of the heavy metal cations (Co 2+, Cu 2+ and Zn 2+) in the bacterial cells. As a bacterial response to heavy metal stress, all the three metals, being taken up by bacterial cells from the culture medium (0.2 mM) in significant amounts (ca. 0.12, 0.48 and 4.2 mg per gram of dry biomass for Co, Cu and Zn, respectively), are shown to induce essential metabolic changes in the bacterium revealed in the spectra, including the accumulation of polyester compounds in bacterial cells and their enhanced hydration affecting certain IR vibrational modes of functional groups involved.

  13. Bacteriophytochrome controls carotenoid-independent response to photodynamic stress in a non-photosynthetic rhizobacterium, Azospirillum brasilense Sp7.

    Science.gov (United States)

    Kumar, Santosh; Kateriya, Suneel; Singh, Vijay Shankar; Tanwar, Meenakshi; Agarwal, Shweta; Singh, Hina; Khurana, Jitendra Paul; Amla, Devinder Vijay; Tripathi, Anil Kumar

    2012-01-01

    Ever since the discovery of the role of bacteriophytochrome (BphP) in inducing carotenoid synthesis in Deinococcus radiodurans in response to light the role of BphPs in other non-photosynthetic bacteria is not clear yet. Azospirillum brasilense, a non-photosynthetic rhizobacterium, harbours a pair of BphPs out of which AbBphP1 is a homolog of AtBphP1 of Agrobacterium tumefaciens. By overexpression, purification, biochemical and spectral characterization we have shown that AbBphP1 is a photochromic bacteriophytochrome. Phenotypic study of the ΔAbBphP1 mutant showed that it is required for the survival of A. brasilense on minimal medium under red light. The mutant also showed reduced chemotaxis towards dicarboxylates and increased sensitivity to the photooxidative stress. Unlike D. radiodurans, AbBphP1 was not involved in controlling carotenoid synthesis. Proteome analysis of the ΔAbBphP1 indicated that AbBphP1 is involved in inducing a cellular response that enables A. brasilense in regenerating proteins that might be damaged due to photodynamic stress.

  14. Evidence for ferritin as dominant iron-bearing species in the rhizobacterium Azospirillum brasilense Sp7 provided by low-temperature/in-field Mössbauer spectroscopy.

    Science.gov (United States)

    Kovács, Krisztina; Kamnev, Alexander A; Pechoušek, Jiří; Tugarova, Anna V; Kuzmann, Ernő; Machala, Libor; Zbořil, Radek; Homonnay, Zoltán; Lázár, Károly

    2016-02-01

    For the ubiquitous diazotrophic rhizobacterium Azospirillum brasilense, which has been attracting the attention of researchers worldwide for the last 35 years owing to its significant agrobiotechnological and phytostimulating potential, the data on iron acquisition and its chemical speciation in cells are scarce. In this work, for the first time for azospirilla, low-temperature (at 80 K, 5 K, as well as at 2 K without and with an external magnetic field of 5 T) transmission Mössbauer spectroscopic studies were performed for lyophilised biomass of A. brasilense (wild-type strain Sp7 grown with (57)Fe(III) nitrilotriacetate complex as the sole source of iron) to enable quantitative chemical speciation analysis of the intracellular iron. In the Mössbauer spectrum at 80 K, a broadened quadrupole doublet of high-spin iron(III) was observed with a few percent of a high-spin iron(II) contribution. In the spectrum measured at 5 K, a dominant magnetically split component appeared with the parameters typical of ferritin species from other bacteria, together with a quadrupole doublet of a superparamagnetic iron(III) component and a similarly small contribution from the high-spin iron(II) component. The Mössbauer spectra recorded at 2 K (with or without a 5 T external field) confirmed the assignment of ferritin species. About 20% of total Fe in the dry cells of A. brasilense strain Sp7 were present in iron(III) forms superparamagnetic at both 5 and 2 K, i.e. either different from ferritin cores or as ferritin components with very small particle sizes.

  15. [Changes in Cell Surface Properties and Biofilm Formation Efficiency in Azospirillum brasilense Sp245 Mutants in the Putative Genes of Lipid Metabolism mmsB1 and fabG1].

    Science.gov (United States)

    Shumilova, E; Shelud'ko, A V; Filip'echeva, Yu A; Evstigneeva, S S; Ponomareva, E G; Petrova, L P; Katsy, E I

    2016-01-01

    The previously obtained insertion mutants ofAzospirillum brasilense Sp245 in the genes mmsBl and fabG1 (strains SK039 and Sp245.1610, respectively) were characterized by impaired flagellation and motility. The putative products of expression of these genes are 3-hydroxyisobutyrate dehydrogenase and 3-oxoacyl-[acyl-carrier protein] reductase, respectively. In the present work, A. brasilense- Sp245 strains SK039 and Sp245.1610 were found to have differences in the content of 3-hydroxyhexadecanoic, hexadecanoic, 3-hydroxytetradecanoic, hexadecenoic, octadecenoic, and nonadecanoic acids in their lipopolysaccharide prepa- rations, as well as in cell hydrophobicity and hemagglutination activity and dynamics of cell aggregation, in biomass amount, and in the relative content of lipopolysaccharide antigens in mature biofilms formed on hydrophilic or hydrophobic surfaces.

  16. [Changes in Cell Surface Properties and Biofilm Formation Efficiency in Azospirillum brasilense Sp245 Mutants in the Putative Genes of Lipid Metabolism mmsB1 and fabG1].

    Science.gov (United States)

    Shumilova, E; Shelud'ko, A V; Filip'echeva, Yu A; Evstigneeva, S S; Ponomareva, E G; Petrova, L P; Katsy, E I

    2016-01-01

    The previously obtained insertion mutants ofAzospirillum brasilense Sp245 in the genes mmsBl and fabG1 (strains SK039 and Sp245.1610, respectively) were characterized by impaired flagellation and motility. The putative products of expression of these genes are 3-hydroxyisobutyrate dehydrogenase and 3-oxoacyl-[acyl-carrier protein] reductase, respectively. In the present work, A. brasilense- Sp245 strains SK039 and Sp245.1610 were found to have differences in the content of 3-hydroxyhexadecanoic, hexadecanoic, 3-hydroxytetradecanoic, hexadecenoic, octadecenoic, and nonadecanoic acids in their lipopolysaccharide prepa- rations, as well as in cell hydrophobicity and hemagglutination activity and dynamics of cell aggregation, in biomass amount, and in the relative content of lipopolysaccharide antigens in mature biofilms formed on hydrophilic or hydrophobic surfaces. PMID:27476204

  17. An extracytoplasmic function sigma factor cotranscribed with its cognate anti-sigma factor confers tolerance to NaCl, ethanol and methylene blue in Azospirillum brasilense Sp7.

    Science.gov (United States)

    Mishra, Mukti Nath; Kumar, Santosh; Gupta, Namrata; Kaur, Simarjot; Gupta, Ankush; Tripathi, Anil K

    2011-04-01

    Azospirillum brasilense, a plant-growth-promoting rhizobacterium, is exposed to changes in its abiotic environment, including fluctuations in temperature, salinity, osmolarity, oxygen concentration and nutrient concentration, in the rhizosphere and in the soil. Since extra-cytoplasmic function (ECF) sigma factors play an important role in stress adaptation, we analysed the role of ECF sigma factor (also known as RpoE or σ(E)) in abiotic stress tolerance in A. brasilense. An in-frame rpoE deletion mutant of A. brasilense Sp7 was carotenoidless and slow-growing, and was sensitive to salt, ethanol and methylene blue stress. Expression of rpoE in the rpoE deletion mutant complemented the defects in growth, carotenoid biosynthesis and sensitivity to different stresses. Based on data from reverse transcriptase-PCR, a two-hybrid assay and a pull-down assay, we present evidence that rpoE is cotranscribed with chrR and the proteins synthesized from these two overlapping genes interact with each other. Identification of the transcription start site by 5' rapid amplification of cDNA ends showed that the rpoE-chrR operon was transcribed by two promoters. The proximal promoter was less active than the distal promoter, whose consensus sequence was characteristic of RpoE-dependent promoters found in alphaproteobacteria. Whereas the proximal promoter was RpoE-independent and constitutively expressed, the distal promoter was RpoE-dependent and strongly induced in response to stationary phase and elevated levels of ethanol, salt, heat and methylene blue. This study shows the involvement of RpoE in controlling carotenoid synthesis as well as in tolerance to some abiotic stresses in A. brasilense, which might be critical in the adaptation, survival and proliferation of this rhizobacterium in the soil and rhizosphere under stressful conditions.

  18. Alkyl hydroperoxide reductase has a role in oxidative stress resistance and in modulating changes in cell-surface properties in Azospirillum brasilense Sp245.

    Science.gov (United States)

    Wasim, Mariam; Bible, Amber N; Xie, Zhihong; Alexandre, Gladys

    2009-04-01

    An ahpC mutant derivative of Azospirillum brasilense Sp245 (strain SK586) that encodes an alkyl hydroperoxide reductase was found to be more sensitive to oxidative stress caused by organic hydroperoxides compared with the wild-type. In addition, the ahpC mutant strain had multiple defects in a large array of cellular functions that were consistent with alteration of cell-surface properties, such as cell morphology in stationary phase, Calcofluor White-, Congo Red- and lectin-binding abilities, as well as cell-to-cell aggregation and flocculation. All phenotypes of the ahpC mutant were complemented by in trans expression of AhpC, and overexpression of AhpC in the wild-type strain was found to affect the same set of phenotypes, suggesting that the pleiotropic effects were caused by the ahpC mutation. SK586 was also found to be fully motile, but it lost motility at a higher rate than the wild-type during growth, such that most SK586 cells were non-motile in stationary phase. Despite these defects, the mutant did not differ from the wild-type in short-term colonization of sterile wheat roots when inoculated alone, and in competition with the wild-type strain; this implied that AhpC activity may not endow the cells with a competitive advantage in colonization under these conditions. Although the exact function of AhpC in affecting these phenotypes remains to be determined, changes in cell morphology, surface properties, cell-to-cell aggregation and flocculation are common adaptive responses to various stresses in bacteria, and the data obtained here suggest that AhpC contributes to modulating such stress responses in A. brasilense.

  19. ESTUDIO DE LA INTERACCIÓN PLANTA-Azospirillum EN EL CULTIVO CAÑA DE AZÚCAR (Saccharum sp.

    Directory of Open Access Journals (Sweden)

    Juana Pérez

    2005-01-01

    Full Text Available Se realizó el aislamiento y la caracterización de cepas nativas de Azospirillum en la rizosfera de las variedades comerciales de caña de azúcar Ja60-5 y C266-70 en los suelos Ferralítico Rojo y Ferralítico Amarillento de las provincias de La Habana y Ciego de Avila. A los aislamientos se les evaluó la actividad nitrogenasa mediante la técnica de reducción del acetileno y la actividad estimuladora del crecimiento en vitroplantas de caña de azúcar. Las cepas fueron caracterizadas mediante pruebas morfológicas y bioquímicas. Se encontraron concentraciones de bacterias del orden de 104 cel. g -1 de raíces, correspondiendo los mayores valores a la variedad Ja60-5 en ambos suelos. Se aislaron cuatro cepas con características propias del género Azospirillum, seleccionándose la cepa 8 INICA de Azospirillum brasilense para estudios posteriores, por sus elevados valores de reducción de acetileno y su mayor efecto sobre el crecimiento de vitroplantas de caña de azúcar.

  20. ESTUDIO DEL EFECTO QUIMIOTÁCTICO DE LOS EXUDADOS RADICALES DEL ARROZ SOBRE Azospirillum brasilense Sp7 Y A. brasilense R5(15. PRODUCCIÓN DE AUXINAS POR AMBAS CEPAS

    Directory of Open Access Journals (Sweden)

    Mabel Pazos

    2003-01-01

    Full Text Available El género Azospirillum agrupa bacterias diazotróficas de vida libre, ampliamente encontradas en suelos tropicales y subtropicales, en asociación con raíces de cultivos de importancia económica como arroz, trigo y diversas especies vegetales. La gran mayoría de los estudios realizados con este género han demostrado su distribución prácticamente universal y sus numerosos efectos sobre el crecimiento de las plantas que coloniza. En este trabajo se demuestra el efecto quimiotáctico que ejercen los exudados radicales del arroz variedad J-104 sobre dos cepas de A. brasilense (R5(15 y Sp7, así como la capacidad de ambas de producir auxinas 16.60 mg.mL-1 y 11.82 mg.mL-1 respectivamente.

  1. [Insertional mutation in the AZOBR_p60120 gene is accompanied by defects in the synthesis of lipopolysaccharide and calcofluor-binding polysaccharides in the bacterium Azospirillum brasilense Sp245].

    Science.gov (United States)

    Katsy, E I; Prilipov, A G

    2015-03-01

    In the bacterium Azospirillum brasilense Sp245, extracellular calcofluor-binding polysaccharides (Cal+ phenotype) and two types of lipopolysaccharides, LPSI and LPSII, were previously identified. These lipopolysaccharides share the same repeating O-polysaccharide unit but have different antigenic structures and different charges of their O-polysaccharides and/or core oligosaccharides. Several dozens of predicted genes involved in the biosynthesis of polysaccharides have been localized in the AZOBR_p6 plasmid of strain Sp245 (GenBank accession no. HE577333). In the present work, it was demonstrated that an artificial transposon Omegon-Km had inserted into the central region of the AZOBR_p60120 gene in the A. brasilense Sp245 LPSI- Cal- KM252 mutant. In A. brasilense strain Sp245, this plasmid gene encodes a putative glycosyltransferase containing conserved domains characteristic of the enzymes participating in the synthesis of O-polysaccharides and capsular polysaccharides (accession no. YP004987664). In mutant KM252, a respective predicted protein is expected to be completely inactivated. As a result of the analysis of the EcoRI fragment of the AZOBR_p6 plasmid, encompassing the AZOBR_p60120 gene and a number of other loci, novel data on the structure of AZOBR_p6 were obtained: an approximately 5-kb gap (GenBank accession no. KM189439) was closed in the nucleotide sequence of this plasmid.

  2. [Biosynthesis of gold nanoparticles by Azospirillum brasilense].

    Science.gov (United States)

    Kupriashina, M A; Vetchinkina, E P; Burov, A M; Ponomareva, E G; Nikitina, V E

    2014-01-01

    Plant-associated nitrogen-fixing soil bacteria Azospirillum brasilense were shown to reduce the gold of chloroauric acid to elemental gold, resulting in formation of gold nanoparicles. Extracellular phenoloxidizing enzymes (laccases and Mn peroxidases) were shown to participate in reduction of Au+3 (HAuCl4) to Au(0). Transmission electron microscopy revealed accumulation of colloidal gold nanoparticles of diverse shape in the culture liquid of A. brasilense strains Sp245 and Sp7. The size of the electron-dense nanospheres was 5 to 50 nm, and the size of nanoprisms varied from 5 to 300 nm. The tentative mechanism responsible for formation of gold nanoparticles is discussed.

  3. EFECTO DE LA INOCULACIÓN DE Azospirillum brasilense y Glomus sp. EN Gmelina arborea DURANTE SU GERMINACIÓN Y MANEJO EN VIVERO

    Directory of Open Access Journals (Sweden)

    Jhon Alexander Zambrano

    2008-09-01

    Full Text Available Seeds of Gmelina arborea at three different maturity degrees were inoculated with Glomus manihotis,Glomus occultum and Azospirillum brasilense immobilized in alginate microbeads. Inoculated seedswere sown in two different growing systems: soil and compacted| peat-Jiffy®. Forty-one days aftersowing (das, the effects of growing system and microorganism application on seed germination weredetermined. Forty-seven das, mycorrhization percentages and plant height were evaluated. Resultsshowed that the growing system and the inoculation of A. brasilense have a significant effect (p<0.01on the germination of G. arborea seeds. A positive correlation between mycorrhization and plantheight was found during the initial stage of establishment in greenhouse conditions (0.61 p=0.03. Inaddition, there is a synergic effect of both types of microorganisms on mycorrhization.

  4. A SAM-dependent methyltransferase cotranscribed with arsenate reductase alters resistance to peptidyl transferase center-binding antibiotics in Azospirillum brasilense Sp7.

    Science.gov (United States)

    Singh, Sudhir; Singh, Chhaya; Tripathi, Anil Kumar

    2014-05-01

    The genome of Azospirillum brasilense harbors a gene encoding S-adenosylmethionine-dependent methyltransferase, which is located downstream of an arsenate reductase gene. Both genes are cotranscribed and translationally coupled. When they were cloned and expressed individually in an arsenate-sensitive strain of Escherichia coli, arsenate reductase conferred tolerance to arsenate; however, methyltransferase failed to do so. Sequence analysis revealed that methyltransferase was more closely related to a PrmB-type N5-glutamine methyltransferase than to the arsenate detoxifying methyltransferase ArsM. Insertional inactivation of prmB gene in A. brasilense resulted in an increased sensitivity to chloramphenicol and resistance to tiamulin and clindamycin, which are known to bind at the peptidyl transferase center (PTC) in the ribosome. These observations suggested that the inability of prmB:km mutant to methylate L3 protein might alter hydrophobicity in the antibiotic-binding pocket of the PTC, which might affect the binding of chloramphenicol, clindamycin, and tiamulin differentially. This is the first report showing the role of PrmB-type N5-glutamine methyltransferases in conferring resistance to tiamulin and clindamycin in any bacterium.

  5. RpoH2 sigma factor controls the photooxidative stress response in a non-photosynthetic rhizobacterium, Azospirillum brasilense Sp7.

    Science.gov (United States)

    Kumar, Santosh; Rai, Ashutosh Kumar; Mishra, Mukti Nath; Shukla, Mansi; Singh, Pradhyumna Kumar; Tripathi, Anil Kumar

    2012-12-01

    Bacteria belonging to the Alphaproteobacteria normally harbour multiple copies of the heat shock sigma factor (known as σ(32), σ(H) or RpoH). Azospirillum brasilense, a non-photosynthetic rhizobacterium, harbours five copies of rpoH genes, one of which is an rpoH2 homologue. The genes around the rpoH2 locus in A. brasilense show synteny with that found in rhizobia. The rpoH2 of A. brasilense was able to complement the temperature-sensitive phenotype of the Escherichia coli rpoH mutant. Inactivation of rpoH2 in A. brasilense results in increased sensitivity to methylene blue and to triphenyl tetrazolium chloride (TTC). Exposure of A. brasilense to TTC and the singlet oxygen-generating agent methylene blue induced several-fold higher expression of rpoH2. Comparison of the proteome of A. brasilense with its rpoH2 deletion mutant and with an A. brasilense strain overexpressing rpoH2 revealed chaperone GroEL, elongation factors (Ef-Tu and EF-G), peptidyl prolyl isomerase, and peptide methionine sulfoxide reductase as the major proteins whose expression was controlled by RpoH2. Here, we show that the RpoH2 sigma factor-controlled photooxidative stress response in A. brasilense is similar to that in the photosynthetic bacterium Rhodobacter sphaeroides, but that RpoH2 is not involved in the detoxification of methylglyoxal in A. brasilense.

  6. Adenosine diphosphate ribosylation of dinitrogenase reductase and adenylylation of glutamine synthetase control ammonia excretion in ethylenediamine-resistant mutants of Azospirillum brasilense Sp7.

    Science.gov (United States)

    Srivastava, A; Tripathi, A K

    2006-10-01

    Azospirillum brasilense is a nitrogen-fixing, root-colonizing bacterium that brings about plant-growth-promoting effects mainly because of its ability to produce phytohormones. Ethylenediamine (EDA)-resistant mutants of A. brasilense were isolated and screened for their higher ability to decrease acetylene and release ammonia in the medium. One of the mutants showed considerably higher levels of acetylene decrease and ammonia excretion. Nitrogenase activity of this mutant was relatively resistant to inhibition by NH(4)Cl. Adenosine triphosphate ribosylation of dinitrogenase reductase in the mutant did not increase even in presence of 10 mM NH(4)Cl. Although the mutant showed decreased glutamine synthetase (GS) activity, neither the levels of GS synthesized by the mutant nor the NH (4) (+) -binding site in the GS differed from those of the parent. The main reason for the release of ammonia by the mutant seems to be the fixation of higher levels of nitrogen than its GS can assimilate, as well as higher levels of adenylylation of GS, which may decrease ammonia assimilation.

  7. Regulation of expression and biochemical characterization of a beta-class carbonic anhydrase from the plant growth-promoting rhizobacterium, Azospirillum brasilense Sp7.

    Science.gov (United States)

    Kaur, Simarjot; Mishra, Mukti Nath; Tripathi, Anil K

    2009-10-01

    Carbonic anhydrase (CA; [EC 4.2.1.1]) is a ubiquitous enzyme catalysing the reversible hydration of CO(2) to bicarbonate, a reaction that supports various biochemical and physiological functions. Genome analysis of Azospirillum brasilense, a nonphotosynthetic, nitrogen-fixing, rhizobacterium, revealed an ORF with homology to beta-class carbonic anhydrases (CAs). Biochemical characteristics of the beta-class CA of A. brasilense, analysed after cloning the gene (designated as bca), overexpressing in Escherichia coli and purifying the protein by affinity purification, revealed that the native recombinant enzyme is a homotetramer, inhibited by the known CA inhibitors. CA activity in A. brasilense cell extracts, reverse transcriptase (RT)-PCR and Western blot analyses showed that bca was constitutively expressed under aerobic conditions. Lower beta-galactosidase activity in A. brasilense cells harbouring bca promoter: lacZ fusion during the stationary phase or during growth on 3% CO(2) enriched air or at acidic pH indicated that the transcription of bca was downregulated by the stationary phase, elevated CO(2) levels and acidic pH conditions. These observations were also supported by RT-PCR analysis. Thus, beta-CA in A. brasilense seems to be required for scavenging CO(2) from the ambient air and the requirement of CO(2) hydration seems to be higher for the cultures growing exponentially at neutral to alkaline pH.

  8. Gene encoding γ-carbonic anhydrase is cotranscribed with argC and induced in response to stationary phase and high CO2 in Azospirillum brasilense Sp7

    Directory of Open Access Journals (Sweden)

    Mishra Mukti N

    2010-07-01

    Full Text Available Abstract Background Carbonic anhydrase (CA is a ubiquitous enzyme catalyzing the reversible hydration of CO2 to bicarbonate, a reaction underlying diverse biochemical and physiological processes. Gamma class carbonic anhydrases (γ-CAs are widespread in prokaryotes but their physiological roles remain elusive. At present, only γ-CA of Methanosarcina thermophila (Cam has been shown to have CA activity. Genome analysis of a rhizobacterium Azospirillum brasilense, revealed occurrence of ORFs encoding one β-CA and two γ-CAs. Results One of the putative γ-CA encoding genes of A. brasilense was cloned and overexpressed in E. coli. Electrometric assays for CA activity of the whole cell extracts overexpressing recombinant GCA1 did not show CO2 hydration activity. Reverse transcription-PCR analysis indicated that gca1 in A. brasilense is co-transcribed with its upstream gene annotated as argC, which encodes a putative N-acetyl-γ-glutamate-phosphate reductase. 5'-RACE also demonstrated that there was no transcription start site between argC and gca1, and the transcription start site located upstream of argC transcribed both the genes (argC-gca1. Using transcriptional fusions of argC-gca1 upstream region with promoterless lacZ, we further demonstrated that gca1 upstream region did not have any promoter and its transcription occurred from a promoter located in the argC upstream region. The transcription of argC-gca1 operon was upregulated in stationary phase and at elevated CO2 atmosphere. Conclusions This study shows lack of CO2 hydration activity in a recombinant protein expressed from a gene predicted to encode a γ-carbonic anhydrase in A. brasilense although it cross reacts with anti-Cam antibody raised against a well characterized γ-CA. The organization and regulation of this gene along with the putative argC gene suggests its involvement in arginine biosynthetic pathway instead of the predicted CO2 hydration.

  9. Results in the application of biofertilizers using Azospirillum and Mycorrhiza, in associations of horticultural crops under semi-greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Dania Bárbara Núñez Sosa

    2013-01-01

    Full Text Available The current research was carried out in the greenhouse “La Condesa”, which belongs to the Empresa de Cultivos Varios “Lenin”, in Jovellanos, Matanzas province. Its main objective was to evaluate the effect of the application of biofertilizer (Azospirillum sp and Micorrizas in combinations of crops (lettuce and radish, or beet and radish. The research included four different treatments: witness, Micorrizas, Azospirillum, Azospirillum +Micorrizas. We used an at random block design. Data were processed after evaluating yields components by using the statistical software called Statgraphics, version 5.0. The research showed a positive response to the application of biofertilizers, resulting in a considerable increase of profits.

  10. Hydrogen oxidation in Azospirillum brasilense

    Energy Technology Data Exchange (ETDEWEB)

    Tibelius, K.

    1984-01-01

    Hydrogen oxidation by Azospirillum brasilense Sp7 was studied in N/sub 2/-fixing and NH/sub 4//sup +/-grown batch cultures. The K/sub m/ for H/sub 2/ of O/sub 2/-dependent H/sup 3/H oxidation in whole cells was 9 uM. The rates of H/sup 3/H and H/sub 2/ oxidation were very similar, indicating that the initial H/sub 2/ activation step in the overall H/sub 2/ oxidation reaction was not rate-limiting and that H/sup 3/H oxidation was a valid measure of H/sub 2/-oxidation activity. Hydrogen-oxidation activity was inhibited irreversibly by air. In N-free cultures the O/sub 2/ optima for O/sub 2/-dependent H/sub 2/ oxidation, ranging from 0.5-1.25% O/sub 2/ depending on the phase of growth, were significantly higher than those of C/sub 2/H/sub 2/ reduction, 0.15-0.35%, suggesting that the H/sub 2/-oxidation system may have a limited ability to aid in the protection of nitrogenase against inactivation by O/sub 2/. Oxygen-dependent H/sub 2/ oxidation was inhibited by NO/sub 2//sup +/, NO, CO, and C/sub 2/H/sub 2/ with apparent K/sub 1/ values of 20, 0.4, 28, and 88 uM, respectively. Hydrogen-oxidation activity was 50 to 100 times higher in denitrifying cultures when the terminal electron acceptor for growth was N/sub 2/O rather than NO/sub 3//sup -/, possibly due to the irreversible inhibition of hydrogenase by NO/sub 2//sup -/ and NO in NO/sub 3//sup -/-grown cultures.

  11. [Determination of Azospirillum Brasilense Cells With Bacteriophages via Electrooptical Analysis of Microbial Suspensions].

    Science.gov (United States)

    Gulii, O I; Karavayeva, O A; Pavlii, S A; Sokolov, O I; Bunin, V D; Ignatov, O V

    2015-01-01

    The dependence-of changes in the electrooptical properties of Azospirillum brasilense cell suspension Sp7 during interaction with bacteriophage ΦAb-Sp7 on the number and time of interactions was studied. Incubation of cells with bacteriophage significantly changed the electrooptical signal within one minute. The selective effect of bacteriophage ΦAb on 18 strains of bacteria of the genus Azospirillum was studied: A. amazonense Ami4, A. brasilense Sp7, Cd, Sp107, Sp245, Jm6B2, Brl4, KR77, S17, S27, SR55, SR75, A. halopraeferans Au4, A. irakense KBC1, K A3, A. lipoferum Sp59b, SR65 and RG20a. We determined the limit of reliable determination of microbial cells infected with bacteriophage: - 10(4) cells/mL. The presence of foreign cell cultures of E. coli B-878 and E. coli XL-1 did not complicate the detection of A brasilense Sp7 cells with the use of bacteriophage ΦAb-Sp7. The results demonstrated that bacteriophage (ΦAb-Sp7 can be used for the detection of Azospirillum microbial cells via t electrooptical analysis of cell suspensions.

  12. Azospirillum brasilense ameliorates the response of Arabidopsis thaliana to drought mainly via enhancement of ABA levels.

    Science.gov (United States)

    Cohen, Ana C; Bottini, Rubén; Pontin, Mariela; Berli, Federico J; Moreno, Daniela; Boccanlandro, Hernán; Travaglia, Claudia N; Piccoli, Patricia N

    2015-01-01

    Production of phytohormones is one of the main mechanisms to explain the beneficial effects of plant growth-promoting rhizobacteria (PGPR) such as Azospirillum sp. The PGPRs induce plant growth and development, and reduce stress susceptibility. However, little is known regarding the stress-related phytohormone abscisic acid (ABA) produced by bacteria. We investigated the effects of Azospirillum brasilense Sp 245 strain on Arabidopsis thaliana Col-0 and aba2-1 mutant plants, evaluating the morphophysiological and biochemical responses when watered and in drought. We used an in vitro-grown system to study changes in the root volume and architecture after inoculation with Azospirillum in Arabidopsis wild-type Col-0 and on the mutant aba2-1, during early growth. To examine Arabidopsis development and reproductive success as affected by the bacteria, ABA and drought, a pot experiment using Arabidopsis Col-0 plants was also carried out. Azospirillum brasilense augmented plant biomass, altered root architecture by increasing lateral roots number, stimulated photosynthetic and photoprotective pigments and retarded water loss in correlation with incremented ABA levels. As well, inoculation improved plants seed yield, plants survival, proline levels and relative leaf water content; it also decreased stomatal conductance, malondialdehyde and relative soil water content in plants submitted to drought. Arabidopsis inoculation with A. brasilense improved plants performance, especially in drought.

  13. The Azospirillum brasilense rpoN gene is involved in nitrogen fixation, nitrate assimilation, ammonium uptake, and flagellar biosynthesis.

    Science.gov (United States)

    Milcamps, A; Van Dommelen, A; Stigter, J; Vanderleyden, J; de Bruijn, F J

    1996-05-01

    The rpoN (ntrA) gene (encoding sigma 54) of Azospirillum brasilense Sp7 was isolated by using conserved rpoN primers and the polymerase chain reaction, and its nucleotide sequence was determined. The deduced amino acid sequence of the RpoN protein was found to share a high degree of homology with other members of the sigma 54 family. Two additional open reading frames were found in the Azospirillum brasilense rpoN region, with significant similarity to equivalent regions surrounding the rpoN locus in other bacteria. An rpoN mutant of Azospirillum brasilense Sp7 was constructed by gene replacement and found to be defective in nitrogen fixation, nitrate assimilation, and ammonium uptake. Lack of ammonium uptake was also found in previously isolated Azospirillum brasilense ntrB and ntrC mutants, further supporting the role of the ntr system in this process. In addition, the rpoN mutant was found to be nonmotile, suggesting a role of RpoN in Azospirillum brasilense flagellar biosynthesis.

  14. Cellular responses during morphological transformation in Azospirillum brasilense and Its flcA knockout mutant.

    Science.gov (United States)

    Hou, Xingsheng; McMillan, Mary; Coumans, Joëlle V F; Poljak, Anne; Raftery, Mark J; Pereg, Lily

    2014-01-01

    FlcA is a response regulator controlling flocculation and the morphological transformation of Azospirillum cells from vegetative to cyst-like forms. To understand the cellular responses of Azospirillum to conditions that cause morphological transformation, proteins differentially expressed under flocculation conditions in A. brasilense Sp7 and its flcA knockout mutant were investigated. Comparison of 2-DE protein profiles of wild-type (Sp7) and a flcA deletion mutant (Sp7-flcAΔ) revealed a total of 33 differentially expressed 2-DE gel spots, with 22 of these spots confidently separated to allow protein identification. Analysis of these spots by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and MASCOT database searching identified 48 proteins (≥10% emPAI in each spot). The functional characteristics of these proteins included carbon metabolism (beta-ketothiolase and citrate synthase), nitrogen metabolism (Glutamine synthetase and nitric oxide synthase), stress tolerance (superoxide dismutase, Alkyl hydroperoxidase and ATP-dependent Clp protease proteolytic subunit) and morphological transformation (transducer coupling protein). The observed differences between Sp7 wild-type and flcA- strains enhance our understanding of the morphological transformation process and help to explain previous phenotypical observations. This work is a step forward in connecting the Azospirillum phenome and genome.

  15. Cellular responses during morphological transformation in Azospirillum brasilense and Its flcA knockout mutant.

    Directory of Open Access Journals (Sweden)

    Xingsheng Hou

    Full Text Available FlcA is a response regulator controlling flocculation and the morphological transformation of Azospirillum cells from vegetative to cyst-like forms. To understand the cellular responses of Azospirillum to conditions that cause morphological transformation, proteins differentially expressed under flocculation conditions in A. brasilense Sp7 and its flcA knockout mutant were investigated. Comparison of 2-DE protein profiles of wild-type (Sp7 and a flcA deletion mutant (Sp7-flcAΔ revealed a total of 33 differentially expressed 2-DE gel spots, with 22 of these spots confidently separated to allow protein identification. Analysis of these spots by liquid chromatography-tandem mass spectrometry (LC-MS/MS and MASCOT database searching identified 48 proteins (≥10% emPAI in each spot. The functional characteristics of these proteins included carbon metabolism (beta-ketothiolase and citrate synthase, nitrogen metabolism (Glutamine synthetase and nitric oxide synthase, stress tolerance (superoxide dismutase, Alkyl hydroperoxidase and ATP-dependent Clp protease proteolytic subunit and morphological transformation (transducer coupling protein. The observed differences between Sp7 wild-type and flcA- strains enhance our understanding of the morphological transformation process and help to explain previous phenotypical observations. This work is a step forward in connecting the Azospirillum phenome and genome.

  16. Azospirillum lectin – induced changes in the content of nitric oxide in wheat seedling roots

    Directory of Open Access Journals (Sweden)

    Alen’kina S.A.

    2010-11-01

    Full Text Available The lectin of Azospirillum brasilense Sp7 at 40 μg ml-1 elicited two peaks of induction of nitric oxide synthesis in the roots of wheat seedlings after 3 and 26 h of coincubation. The lectin of A. brasilense Sp7.2.3, a mutant defective in lectin activity, produced the same effect, but the activation of nitric oxide synthesis in the roots was less in the case of 26-h incubation. Exposure to the lectins for 3 h increased citrulline synthesis in the plant cell to the same extent. This finding indicated that the Azospirillum lectins activate nitric oxide production through the NO signal system of plants, thereby acting as inducers of adaptation processes in the roots of wheat seedlings.

  17. STUDY OF AZOSPIRILLUM LECTINS INFLUENCE ON HYDROGEN PEROXIDE PRODUCTION IN WHEAT-ROOTS

    Directory of Open Access Journals (Sweden)

    Alen’kina S.A.

    2009-12-01

    Full Text Available It was found that two cell-surface lectins isolated from the nitrogen-fixing soil bacterium Azospirillum brasilense Sp7 and from its mutant defective in lectin activity, A. brasilense Sp7.2.3 can stimulate rapid formation of hydrogen peroxide, associated with an increase in the activities of oxalate oxidase and peroxidase in the roots of wheat seedlings. The most advantageous and most rapidly induced pathway of hydrogen peroxide formation was the oxidation of oxalic acid by oxalate oxidase because in this case, a 10-min treatment of the roots with the lectins at 10 µg ml-1 was sufficient. The data from this study attest that the Azospirillum lectins can act as inducers of adaptation processes in the roots of wheat seedlings.

  18. [Effect of lectins from Azospirillum brasilense to peroxidase and oxalate oxidase activity regulation in wheat roots].

    Science.gov (United States)

    Alen'kina, S A; Nikitina, V E

    2010-01-01

    Lectins were extracted from the surface of nitrogen-fixing soil bacteria Azospirillum brasilense Sp7 and from its mutant A. brasilense Sp7.2.3 defective in lectin activity. The ability oflectins to stimulate the rapid formation of hydrogen peroxide related to increase of oxalate oxidase and peroxidase activity in the roots of wheat seedlings has been demonstrated. The most rapid induced pathway of hydrogen peroxide formation in the roots of wheat seedlings was the oxalic acid oxidation by oxalate oxidase which is the effect oflectin in under 10 min in a concentration of 10 microg/ml. The obtained results show that lectins from Azospirillum are capable of inducing the adaptation processes in the roots of wheat seedlings.

  19. Mutants with Enhanced Nitrogenase Activity in Hydroponic Azospirillum brasilense-Wheat Associations

    OpenAIRE

    Pereg Gerk, Lily; Gilchrist, Kate; Kennedy, Ivan R.

    2000-01-01

    The effect of a mutation affecting flocculation, differentiation into cyst-like forms, and root colonization on nitrogenase expression by Azospirillum brasilense is described. The gene flcA of strain Sp7 restored these phenotypes in spontaneous mutants of both strains Sp7 and Sp245. Employing both constitutive pLA-lacZ and nifH-lacZ reporter fusions expressed in situ, the colony morphology, colonization pattern, and potential for nitrogenase activity of spontaneous mutants and flcA Tn5-induce...

  20. Influence of oxide scales on the corrosion behaviors of B510L hot-rolled steel strips

    Science.gov (United States)

    Man, Cheng; Dong, Chao-fang; Xue, Hui-bin; Xiao, Kui; Li, Xiao-gang; Qi, Hui-bin

    2016-07-01

    The influence of oxide scales on the corrosion behaviors of B510L hot-rolled steel strips was investigated in this study. Focused ion beams and scanning electron microscopy were used to observe the morphologies of oxide scales on the surface and cross sections of the hot-rolled steel. Raman spectroscopy and X-ray diffraction were used for the phase analysis of the oxide scales and corrosion products. The corrosion potential and impedance were measured by anodic polarization and electrochemical impedance spectroscopy. According to the results, oxide scales on the hot-rolled strips mainly comprise iron and iron oxides. The correlation between mass gain and test time follows a power exponential rule in the damp-heat test. The corrosion products are found to be mainly composed of γ-FeOOH, Fe3O4, α-FeOOH, and γ-Fe2O3. The contents of the corrosion products are different on the surfaces of the steels with and without oxide scales. The steel with oxide scales is found to show a higher corrosion resistance and lower corrosion rate.

  1. Identification of the glutamine synthetase adenylyltransferase of Azospirillum brasilense.

    Science.gov (United States)

    Van Dommelen, Anne; Spaepen, Stijn; Vanderleyden, Jozef

    2009-04-01

    Glutamine synthetase, a key enzyme in nitrogen metabolism of both prokaryotes and eukaryotes, is strictly regulated. One means of regulation is the modulation of activity through adenylylation catalyzed by adenylyltransferases. Using PCR primers based on conserved sequences in glutamine synthetase adenylyltransferases, we amplified part of the glnE gene of Azospirillum brasilense Sp7. The complete glnE sequence of A. brasilense Sp245 was retrieved from the draft genome sequence of this organism (http://genomics.ornl.gov/research/azo/). Adenylyltransferase is a bifunctional enzyme consisting of an N-terminal domain responsible for deadenylylation activity and a C-terminal domain responsible for adenylylation activity. Both domains are partially homologous to each other. Residues important for catalytic activity were present in the deduced amino acid sequence of the A. brasilense Sp245 glnE sequence. A glnE mutant was constructed in A. brasilense Sp7 by inserting a kanamycin resistance cassette between the two active domains of the enzyme. The resulting mutant was unable to adenylylate the glutamine synthetase enzyme and was impaired in growth when shifted from nitrogen-poor to nitrogen-rich medium.

  2. Comparison of two Cellulomonas strains and their interaction with Azospirillum brasilense in degradation of wheat straw and associated nitrogen fixation

    Energy Technology Data Exchange (ETDEWEB)

    Halsall, D.M.; Gibson, A.H.

    1986-04-01

    A mutant strain of Cellulomonas sp. CS1-17 was compared with Cellulomonas gelida 2480 as the cellulolytic component of a mixed culture which was responsible for the breakdown of wheat straw to support asymbiotic nitrogen fixation by Azospirillum brasilense Sp7 (ATCC 29145). Cellulomonas sp. strain CS1-17 was more efficient than was C. gelida in cellulose breakdown at lower oxygen concentrations and, in mixed culture with A. brasilense, it supported higher nitrogenase activity(C/sub 2/H/sub 2/ reduction) and nitrogen fixation with straw as the carbon source. Based on gravimetric determinations of straw breakdown and total N determinations, the efficiency of nitrogen fixation was 72 and 63 mg of N per g of straw utilized for the mixtures containing Cellulomonas sp. and C. gelida, respectively. Both Cellulomonas spp. and Azospirillum spp. exhibited a wide range of pH tolerance. When introduced into sterilized soil, the Cellulomonas sp.-Azospirillum brasilense association was more effective in nitrogen fixation at a pH of 7.0 than at the native soil pH (5.6). This was also true of the indigenous diazotrophic microflora of this soil. The potential implications of this work to the field situation are discussed. 16 references.

  3. Mutants with enhanced nitrogenase activity in hydroponic Azospirillum brasilense-wheat associations.

    Science.gov (United States)

    Pereg Gerk, L; Gilchrist, K; Kennedy, I R

    2000-05-01

    The effect of a mutation affecting flocculation, differentiation into cyst-like forms, and root colonization on nitrogenase expression by Azospirillum brasilense is described. The gene flcA of strain Sp7 restored these phenotypes in spontaneous mutants of both strains Sp7 and Sp245. Employing both constitutive pLA-lacZ and nifH-lacZ reporter fusions expressed in situ, the colony morphology, colonization pattern, and potential for nitrogenase activity of spontaneous mutants and flcA Tn5-induced mutants were established. The results of this study show that the ability of Sp7 and Sp245 mutant strains to remain in a vegetative form improved their ability to express nitrogenase activity in association with wheat in a hydroponic system. Restoring the cyst formation and colonization pattern to the spontaneous mutant Sp7-S reduced nitrogenase activity rates in association with plants to that of the wild-type Sp7. Although Tn5-induced flcA mutants showed higher potentials for nitrogenase expression than Sp7, their potentials were lower than that of Sp7-S, indicating that other factors in this strain contribute to its exceptional nitrogenase activity rates on plants. The lack of lateral flagella is not one of these factors, as Sp7-PM23, a spontaneous mutant impaired in swarming and lateral-flagellum production but not in flocculation, showed wild-type nitrogenase activity and expression. The results also suggest factors of importance in evolving an effective symbiosis between Azospirillum and wheat, such as increasing the availability of microaerobic niches along the root, increased supply of carbon sources by the plant, and the retention of the bacterial cells in vegetative form for faster metabolism. PMID:10788397

  4. Mutants with Enhanced Nitrogenase Activity in Hydroponic Azospirillum brasilense-Wheat Associations

    Science.gov (United States)

    Pereg Gerk, Lily; Gilchrist, Kate; Kennedy, Ivan R.

    2000-01-01

    The effect of a mutation affecting flocculation, differentiation into cyst-like forms, and root colonization on nitrogenase expression by Azospirillum brasilense is described. The gene flcA of strain Sp7 restored these phenotypes in spontaneous mutants of both strains Sp7 and Sp245. Employing both constitutive pLA-lacZ and nifH-lacZ reporter fusions expressed in situ, the colony morphology, colonization pattern, and potential for nitrogenase activity of spontaneous mutants and flcA Tn5-induced mutants were established. The results of this study show that the ability of Sp7 and Sp245 mutant strains to remain in a vegetative form improved their ability to express nitrogenase activity in association with wheat in a hydroponic system. Restoring the cyst formation and colonization pattern to the spontaneous mutant Sp7-S reduced nitrogenase activity rates in association with plants to that of the wild-type Sp7. Although Tn5-induced flcA mutants showed higher potentials for nitrogenase expression than Sp7, their potentials were lower than that of Sp7-S, indicating that other factors in this strain contribute to its exceptional nitrogenase activity rates on plants. The lack of lateral flagella is not one of these factors, as Sp7-PM23, a spontaneous mutant impaired in swarming and lateral-flagellum production but not in flocculation, showed wild-type nitrogenase activity and expression. The results also suggest factors of importance in evolving an effective symbiosis between Azospirillum and wheat, such as increasing the availability of microaerobic niches along the root, increased supply of carbon sources by the plant, and the retention of the bacterial cells in vegetative form for faster metabolism. PMID:10788397

  5. Bacteriophage prevalence in the genus Azospirillum and analysis of the first genome sequence of an Azospirillum brasilense integrative phage.

    Science.gov (United States)

    Boyer, Mickaël; Haurat, Jacqueline; Samain, Sylvie; Segurens, Béatrice; Gavory, Frédérick; González, Víctor; Mavingui, Patrick; Rohr, René; Bally, René; Wisniewski-Dyé, Florence

    2008-02-01

    The prevalence of bacteriophages was investigated in 24 strains of four species of plant growth-promoting rhizobacteria belonging to the genus Azospirillum. Upon induction by mitomycin C, the release of phage particles was observed in 11 strains from three species. Transmission electron microscopy revealed two distinct sizes of particles, depending on the identity of the Azospirillum species, typical of the Siphoviridae family. Pulsed-field gel electrophoresis and hybridization experiments carried out on phage-encapsidated DNAs revealed that all phages isolated from A. lipoferum and A. doebereinerae strains had a size of about 10 kb whereas all phages isolated from A. brasilense strains displayed genome sizes ranging from 62 to 65 kb. Strong DNA hybridizing signals were shown for most phages hosted by the same species whereas no homology was found between phages harbored by different species. Moreover, the complete sequence of the A. brasilense Cd bacteriophage (phiAb-Cd) genome was determined as a double-stranded DNA circular molecule of 62,337 pb that encodes 95 predicted proteins. Only 14 of the predicted proteins could be assigned functions, some of which were involved in DNA processing, phage morphogenesis, and bacterial lysis. In addition, the phiAb-Cd complete genome was mapped as a prophage on a 570-kb replicon of strain A. brasilense Cd, and a region of 27.3 kb of phiAb-Cd was found to be duplicated on the 130-kb pRhico plasmid previously sequenced from A. brasilense Sp7, the parental strain of A. brasilense Cd.

  6. Characterization of native strains of Azospirillum spp. and its effect on growth of Oryza sativa L. “rice” in Lambayeque

    Directory of Open Access Journals (Sweden)

    Franklin García

    2010-06-01

    Full Text Available This research was conducted to characterize and determine the effect of native strains of Azospirillum spp. on growth of Oryza sativa L. "rice" as an alternative for the reduction of chemical fertilizers. The bacteria were isolated from roots of rice in Lambayeque. Fragments of previously disinfected roots were planted in Nfb semisolid medium, were nitrogen-fixing bacteria were recognized by a whitish film on the surface and turn from green to blue. The genus Azospirillum was identified in Congo red agar medium, obtained 96 isolates with production of 2.69 to 38.02 ppm indoleacetic acid and 7.95 to 29.09 ppm of fixed nitrogen. The four strains with the highest values were inoculated independently and in combination with 50 and 100 % urea in Tinajones INIA508 rice. It used a completely randomized design and including witnesses’ 50 and 100 % urea and absolute control. All native strains increased height and dry matter of shoot and roots, with effectiveness index of up to 21.77, 102.06 and 126.11 % compared to untreated control. Azospirillum sp. GM-86 selected by the highest value of indoleacetic acid, reached the highest level of effectiveness in height and root dry biomass. The application of 50 % úrea with Azospirillum spp. increased rates of effectiveness. It demonstrated the potential of native strains of Azospirillum spp. to increase the growth of rice as well as the possibility to use associate with low doses of urea.

  7. Enhanced Mineral Uptake by Zea mays and Sorghum bicolor Roots Inoculated with Azospirillum brasilense†

    OpenAIRE

    Lin, Willy; Okon, Yaacov; Hardy, Ralph W. F.

    1983-01-01

    Inoculation of corn (Zea mays) seeds with Azospirillum brasilense strain Cd or Sp 7 significantly enhanced (30 to 50% over controls) the uptake of NO3−, K+, and H2PO4− into 3- to 4-day- and 2-week-old root segments. No gross changes in root morphology were observed; altered cell arrangement in the outer four or five layers of the cortex was seen in photomicrographs of cross sections of inoculated corn roots. The surface activity involved in ion uptake probably increased, as shown by the darke...

  8. Survival of Azospirillum brasilense in the Bulk Soil and Rhizosphere of 23 Soil Types

    OpenAIRE

    Bashan, Y.; Puente, M. E.; Rodriguez-Mendoza, M. N.; Toledo, G.; Holguin, G.; Ferrera-Cerrato, R.; Pedrin, S.

    1995-01-01

    The survival of Azospirillum brasilense Cd and Sp-245 in the rhizosphere of wheat and tomato plants and in 23 types of plant-free sterilized soils obtained from a wide range of environments in Israel and Mexico was evaluated. Large numbers of A. brasilense cells were detected in all the rhizospheres tested, regardless of soil type, bacterial strain, the origin of the soil, or the amount of rainfall each soil type received prior to sampling. Survival of A. brasilense in soils without plants di...

  9. Transfer of a plant chitinase gene into a nitrogen-fixing Azospirillum and study of its expression.

    Science.gov (United States)

    Jayaraj, Jayaraman; Muthukrishnan, Subbaratnam; Liang, George H

    2004-07-01

    Azospirillum is used extensively in rice and other cereal crops as a biofertilizer. There is a substantial opportunity to improve the efficiency of this bacterium through the transfer of genes of agricultural importance from other organisms. Chitinases are antifungal proteins, and expression of chitinase genes in Azospirillum would help to develop strains with potential antifungal activities. So far there are no reports about transfer of plant genes into Azospirillum and their expression. The present study was aimed at expressing an antifungal gene (a rice chitinase) of plant origin in Azospirillum brasilense. A rice chitinase cDNA (RC 7) that codes for a 35 kDa protein was subcloned into a broad host range plasmid pDSK519 under the control of LacZ promoter. The plasmid was mobilized into the nitrogen-fixing bacterium, Azospirillum brasilense strain SP51eFL1, through biparental mating. The conjugation frequency was in the range of 35-40 x 10(-6). The transconjugants grew in nitrogen-free media and fixed gaseous nitrogen in vitro. However, their growth and nitrogen-fixing ability were slightly less than those of the wild-type. Expression of the protein was demonstrated through western blotting of the total cell protein, which detected a 35 kDa band that was immuno-reactive to a barley chitinase antibody. The cell lysates also hydrolyzed various chitin substrates, which resulted in release of free sugars demonstrating the chitinase activity of transconjugants. The expressed protein also had antifungal activity as demonstrated by inhibition of growth of the plant pathogenic fungus, Rhizoctonia solani.

  10. Denitrification-derived nitric oxide modulates biofilm formation in Azospirillum brasilense.

    Science.gov (United States)

    Arruebarrena Di Palma, Andrés; Pereyra, Cintia M; Moreno Ramirez, Lizbeth; Xiqui Vázquez, María L; Baca, Beatriz E; Pereyra, María A; Lamattina, Lorenzo; Creus, Cecilia M

    2013-01-01

    Azospirillum brasilense is a rhizobacterium that provides beneficial effects on plants when they colonize roots. The formation of complex bacterial communities known as biofilms begins with the interaction of planktonic cells with surfaces in response to appropriate signals. Nitric oxide (NO) is a signaling molecule implicated in numerous processes in bacteria, including biofilm formation or dispersion, depending on genera and lifestyle. Azospirillum brasilense Sp245 produces NO by denitrification having a role in root growth promotion. We analyzed the role of endogenously produced NO on biofilm formation in A. brasilense Sp245 and in a periplasmic nitrate reductase mutant (napA::Tn5; Faj164) affected in NO production. Cells were statically grown in media with nitrate or ammonium as nitrogen sources and examined for biofilm formation using crystal violet and by confocal laser microscopy. Both strains formed biofilms, but the mutant produced less than half compared with the wild type in nitrate medium showing impaired nitrite production in this condition. NO measurements in biofilm confirmed lower values in the mutant strain. The addition of a NO donor showed that NO influences biofilm formation in a dose-dependent manner and reverses the mutant phenotype, indicating that Nap positively regulates the formation of biofilm in A. brasilense Sp245.

  11. Strain-specific chemotaxis of Azospirillum spp.

    OpenAIRE

    Reinhold, B; Hurek, T; Fendrik, I

    1985-01-01

    Chemotactic responses of three Azospirillum strains originating from different host plants were compared to examine the possible role of chemotaxis in the adaptation of these bacteria to their respective hosts. The chemotaxis to several sugars, amino acids, and organic acids was determined qualitatively by an agar plate assay and quantitatively by a channeled-chamber technique. High chemotactic ratios, up to 40, were obtained with the latter technique. The chemotactic response did not rely up...

  12. Reduction of selenite by Azospirillum brasilense with the formation of selenium nanoparticles.

    Science.gov (United States)

    Tugarova, Anna V; Vetchinkina, Elena P; Loshchinina, Ekaterina A; Burov, Andrei M; Nikitina, Valentina E; Kamnev, Alexander A

    2014-10-01

    The ability to reduce selenite (SeO(3)(2-)) ions with the formation of selenium nanoparticles was demonstrated in Azospirillum brasilense for the first time. The influence of selenite ions on the growth of A. brasilense Sp7 and Sp245, two widely studied wild-type strains, was investigated. Growth of cultures on both liquid and solid (2 % agar) media in the presence of SeO(3)(2-) was found to be accompanied by the appearance of the typical red colouration. By means of transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS) and X-ray fluorescence analysis (XFA), intracellular accumulation of elementary selenium in the form of nanoparticles (50 to 400 nm in diameter) was demonstrated for both strains. The proposed mechanism of selenite-to-selenium (0) reduction could involve SeO(3)(2-) in the denitrification process, which has been well studied in azospirilla, rather than a selenite detoxification strategy. The results obtained point to the possibility of using Azospirillum strains as endophytic or rhizospheric bacteria to assist phytoremediation of, and cereal cultivation on, selenium-contaminated soils. The ability of A. brasilense to synthesise selenium nanoparticles may be of interest to nanobiotechnology for "green synthesis" of bioavailable amorphous red selenium nanostructures.

  13. Colonization and nitrogenase activity of Triticum aestivum (cv. Baccross and Mahdavi) to the dual inoculation with Azospirillum brasilense and Rhizobium meliloti plus 2,4-D.

    Science.gov (United States)

    Mehry, Askary; Akbar, Mostajeran; Giti, Emtiazi

    2008-06-15

    The potential enhancement of root colonization and nitrogenase activity of wheat cultivars (Baccross and Mahdavi) was studied with application of two Azospirillum brasilense strains (native and Sp7) co-inoculated with two Rhizobium meliloti strains (native and DSMZ 30135). The results indicated that the colonization was different due to the strains and cultivars of wheat were used. Native A. brasilense colonized wheat root better than Sp7 strain. However, Baccross cv. reacted better with native Azospirillum compared to Mahdavi cv. which reacted better with Sp7. When plants inoculated with dual inoculants (SP7 with standard Rhizobium), the colonization of Azospirillum were increased significantly (from 1.67 x 10(5) to 22 x 10(5) cfu g(-1) FW for Baccras cv. and 3.67 x 10(5) to 26 x 10(5) cfu g(-1) FW for Mahdavi cultivar). When the standard Rhizobium as co-inoculants changed to the native Rhizobium, the colonization of Azospirillum was higher when compared to the single inoculants but was almost the same when compared to the standard Rhizobium. When the standard or native strains of Rhizobium used as single inoculation of wheat roots, the number of Rhizobium in the wheat roots were not changed significantly. However, when plants co-inoculated with Rhizobium and Azospirillum, the colonization of Rhizobium was increased. Co-inoculation of standard strain of R. melilot with A. brasilense Sp7 showed that the colonization of Rhizobium were increased from 0.67 x 10(5) to 21 x 10(5) cfu g(-1) FW for Baccross cv. and 0.33 x 10(5) to 18 x 10(5) cfu g(-1) FW for Mahdavi cv. This behavior was the same when inoculation of Rhizobium was happened with the native one. In dual inoculation, the highest nitrogenase activity was measured in combination of the local strains (native A. brasilense with the native R. meliloti) and the lower one belongs to the combination of standard strains (Sp7 with standard R. meliloti). The difference in nirtogenase activity for different cultivars of

  14. [Factors inducing transition from growth to dormancy in rhizobacteria Azospirillum brasilense].

    Science.gov (United States)

    Kushneruk, M A; Tugarova, A V; Il'chukova, A V; Slavkina, E A; Starichkova, N I; Bogatyrev, V A; Antoniuk, L P

    2013-01-01

    The factors suppressing division of the cells of the rhizobacterium Azospirillum brasilense and inducing their transition to a dormant state were analyzed. These included the presence of hexylresorcinol or heavy metals (Cu and Co) in the medium, oxygen stress, and transfer of the cells into the physiological saline or phosphate buffer solution. The results were used to develop a protocol for obtaining of uncultured cells of A. brasilense Sp245, a natural symbiont of wheat. The cells lost their ability to grow on synthetic agar medium, but could revert to growth when incubated in freshly prepared liquid medium. Needle-shaped crystals differing from struvite, which has been previously reported for this strain, were found in the dormant culture of A. brasilense Sp245.

  15. Plant Cell Protolytic Enzymes Activity under Exposure to Lectins of Endophytic and Epiphytic Azospirillum Strains

    Directory of Open Access Journals (Sweden)

    S.A. Alen’kina

    2016-05-01

    Full Text Available We studied the ability of lectins isolated from the surface of the two strains of nitrogen-fixing soil bacteria of the genus Azospirillum, A. brasilense Sp7 (epiphytic and A. brasilense Sp245 (endophytic, to show have a regulating effect on the activity of pectinolytic enzymes in the roots of wheat seedlings. Research results showed that the lectins under study can cause the induction of the activity of polygalacturonase, pectinesterase, pectatlyase from the plant cell wall, thereby ensuring the bacteria penetration in the plant tissues, as well as the induction of plants responses which, being combined with growth-stimulating effect of bacteria, contributes to the formation of plants stability and productivity.

  16. [Effect of Azospirillum lectins on the Activity of Proteolytic Enzymes and Their Inhibitors in Wheat Seedling Roots].

    Science.gov (United States)

    Alen'kina, S A; Nikitina, V E

    2015-01-01

    The lectins of associative nitrogen-fixing strains Azospirillum brasilense Sp7 and Sp245 were shown to exerte a multidirectional effect on the activity of acidic (pH 3.5), neutral (6.8), and alkaline (pH 7.8) proteinases. The lectin of the epiphytic A. brasilense Sp7 decreased proteolytic activity at all pH values, whereas the lectin of the endophytic A. brasilense Sp245 activated neutral and alkaline proteinases, while not affecting the alkaline ones. Experiments with protease inhibitors made it possible to conclude that the lectins of the studied A. brasilense strains alter the ratio between the activities of different protease types in germinating seeds. The activity of trypsin inhibitors in wheat seedling roots was found to increase in the presence of the lectins. Our results indicate a broader spectrum of effects of azospirilla lectins on the host plant organism.

  17. The role of the antimicrobial compound 2,4-diacetylphloroglucinol in the impact of biocontrol Pseudomonas fluorescens F113 on Azospirillum brasilense phytostimulators.

    Science.gov (United States)

    Couillerot, Olivier; Combes-Meynet, Emeline; Pothier, Joël F; Bellvert, Floriant; Challita, Elita; Poirier, Marie-Andrée; Rohr, René; Comte, Gilles; Moënne-Loccoz, Yvan; Prigent-Combaret, Claire

    2011-06-01

    Pseudomonads producing the antimicrobial metabolite 2,4-diacetylphloroglucinol (Phl) can control soil-borne phytopathogens, but their impact on other plant-beneficial bacteria remains poorly documented. Here, the effects of synthetic Phl and Phl(+) Pseudomonas fluorescens F113 on Azospirillum brasilense phytostimulators were investigated. Most A. brasilense strains were moderately sensitive to Phl. In vitro, Phl induced accumulation of carotenoids and poly-β-hydroxybutyrate-like granules, cytoplasmic membrane damage and growth inhibition in A. brasilense Cd. Experiments with P. fluorescens F113 and a Phl(-) mutant indicated that Phl production ability contributed to in vitro growth inhibition of A. brasilense Cd and Sp245. Under gnotobiotic conditions, each of the three strains, P. fluorescens F113 and A. brasilense Cd and Sp245, stimulated wheat growth. Co-inoculation of A. brasilense Sp245 and Pseudomonas resulted in the same level of phytostimulation as in single inoculations, whereas it abolished phytostimulation when A. brasilense Cd was used. Pseudomonas Phl production ability resulted in lower Azospirillum cell numbers per root system (based on colony counts) and restricted microscale root colonization of neighbouring Azospirillum cells (based on confocal microscopy), regardless of the A. brasilense strain used. Therefore, this work establishes that Phl(+) pseudomonads have the potential to interfere with A. brasilense phytostimulators on roots and with their plant growth promotion capacity.

  18. Identification, cloning and characterization of cysK, the gene encoding O-acetylserine (thiol)-lyase from Azospirillum brasilense, which is involved in tellurite resistance.

    Science.gov (United States)

    Ramírez, Alberto; Castañeda, Miguel; Xiqui, María L; Sosa, Araceli; Baca, Beatriz E

    2006-08-01

    O-Acetylserine (thiol)-lyase (cysteine synthase) was purified from Azospirillum brasilense Sp7. After hydrolysis of the purified protein, amino acid sequences of five peptides were obtained, which permitted the cloning and sequencing of the cysK gene. The deduced amino acid sequence of cysteine synthase exhibited homology with several putative proteins from Alpha- and Gammaproteobacteria. Azospirillum brasilense Sp7 cysK exhibited 58% identity (72% similarity) with Escherichia coli K12 and Salmonella enterica serovar Typhimurium cysteine synthase proteins. An E. coli auxotroph lacking cysteine synthase loci could be complemented with A. brasilense Sp7 cysK. The 3.0-kb HindIII-EcoRI fragment bearing cysK contained two additional ORFs encoding a putative transcriptional regulator and dUTPase. Insertional disruption of the cysK gene did not produce a cysteine auxotroph, indicating that gene redundancy in the cysteine biosynthetic or other biosynthetic pathways exists in Azospirillum, as already described in other bacteria. Nitrogen fixation was not altered in the mutant strain as determined by acetylene reduction. However, this strain showed an eight-fold reduction in tellurite resistance as compared to the wild-type strain, which was only observed during growth in minimal medium. These data confirm earlier observations regarding the importance of cysteine metabolism in tellurite resistance.

  19. Aggregation of the rhizospheric bacterium Azospirillum brasilense in response to oxygen

    Science.gov (United States)

    Abdoun, Hamid; McMillan, Mary; Pereg, Lily

    2016-04-01

    Azospirillum brasilense spp. have ecological, scientific and agricultural importance. As model plant growth promoting rhizobacteria they interact with a large variety of plants, including important food and cash crops. Azospirillum strains are known for their production of plant growth hormones that enhance root systems and for their ability to fix nitrogen. Azospirillum cells transform in response to environmental cues. The production of exopolysaccharides and cell aggregation during cellular transformation are important steps in the attachment of Azospirillum to roots. We investigate signals that induce cellular transformation and aggregation in the Azospirillum and report on the importance of oxygen to the process of aggregation in this rhizospheric bacterium.

  20. Azospirillum, a free-living nitrogen-fixing bacterium closely associated with grasses: genetic, biochemical and ecological aspects.

    Science.gov (United States)

    Steenhoudt, O; Vanderleyden, J

    2000-10-01

    Azospirillum represents the best characterized genus of plant growth-promoting rhizobacteria. Other free-living diazotrophs repeatedly detected in association with plant roots, include Acetobacter diazotrophicus, Herbaspirillum seropedicae, Azoarcus spp. and Azotobacter. Four aspects of the Azospirillum-plant root interaction are highlighted: natural habitat, plant root interaction, nitrogen fixation and biosynthesis of plant growth hormones. Each of these aspects is dealt with in a comparative way. Azospirilla are predominantly surface-colonizing bacteria, whereas A. diazotrophicus, H. seropedicae and Azoarcus sp. are endophytic diazotrophs. The attachment of Azospirillum cells to plant roots occurs in two steps. The polar flagellum, of which the flagellin was shown to be a glycoprotein, mediates the adsorption step. An as yet unidentified surface polysaccharide is believed to be essential in the subsequent anchoring phase. In Azoarcus sp. the attachment process is mediated by type IV pili. Nitrogen fixation structural genes (nif) are highly conserved among all nitrogen-fixing bacteria, and in all diazotrophic species of the class of proteobacteria examined, the transcriptional activator NifA is required for expression of other nif genes in response to two major environmental signals (oxygen and fixed N). However, the mechanisms involved in this control can vary in different organisms. In Azospirillum brasilense and H. seropedicae (alpha- and beta-subgroup, respectively), NifA is inactive in conditions of excess nitrogen. Activation of NifA upon removal of fixed N seems to involve, either directly or indirectly, the signal transduction protein P(II). The presence of four conserved cysteine residues in the NifA protein might be an indication that NifA is directly sensitive to oxygen. In Azotobacter vinelandii (gamma-subgroup) nifA is cotranscribed with a second gene nifL. The nifL gene product inactivates NifA in response to high oxygen tension and cellular

  1. Azospirillum, a free-living nitrogen-fixing bacterium closely associated with grasses: genetic, biochemical and ecological aspects.

    Science.gov (United States)

    Steenhoudt, O; Vanderleyden, J

    2000-10-01

    Azospirillum represents the best characterized genus of plant growth-promoting rhizobacteria. Other free-living diazotrophs repeatedly detected in association with plant roots, include Acetobacter diazotrophicus, Herbaspirillum seropedicae, Azoarcus spp. and Azotobacter. Four aspects of the Azospirillum-plant root interaction are highlighted: natural habitat, plant root interaction, nitrogen fixation and biosynthesis of plant growth hormones. Each of these aspects is dealt with in a comparative way. Azospirilla are predominantly surface-colonizing bacteria, whereas A. diazotrophicus, H. seropedicae and Azoarcus sp. are endophytic diazotrophs. The attachment of Azospirillum cells to plant roots occurs in two steps. The polar flagellum, of which the flagellin was shown to be a glycoprotein, mediates the adsorption step. An as yet unidentified surface polysaccharide is believed to be essential in the subsequent anchoring phase. In Azoarcus sp. the attachment process is mediated by type IV pili. Nitrogen fixation structural genes (nif) are highly conserved among all nitrogen-fixing bacteria, and in all diazotrophic species of the class of proteobacteria examined, the transcriptional activator NifA is required for expression of other nif genes in response to two major environmental signals (oxygen and fixed N). However, the mechanisms involved in this control can vary in different organisms. In Azospirillum brasilense and H. seropedicae (alpha- and beta-subgroup, respectively), NifA is inactive in conditions of excess nitrogen. Activation of NifA upon removal of fixed N seems to involve, either directly or indirectly, the signal transduction protein P(II). The presence of four conserved cysteine residues in the NifA protein might be an indication that NifA is directly sensitive to oxygen. In Azotobacter vinelandii (gamma-subgroup) nifA is cotranscribed with a second gene nifL. The nifL gene product inactivates NifA in response to high oxygen tension and cellular

  2. [Electrooptical properties of soil nitrogen-fixing bacterium Azospirillum brasilense: effect of copper ions].

    Science.gov (United States)

    Ignatov, O V; Kamnev, A A; Markina, L N; Antoniuk, L P; Kolina, M; Ignatov, V V

    2001-01-01

    The effects of copper ions on the uptake of some essential metals in the biomass and the electrooptical properties of cell suspensions of the nitrogen-fixing soil bacterium Azospirillum brasilense sp. 245 were studied. Copper cations were shown to be effectively taken up by the cell biomass from the culture medium. The addition of copper ions increased the rate of uptake of some other metals present in the culture medium. This was accompanied by changes in the electrooptical characteristics of cell suspension as measured within the orienting electric field frequency range of 10 to 10,000 kHz. The effects observed during short-term incubation of A. brasilense in the presence of copper cations were less significant than during long-term incubation. These results can be used for rapid screening of microbial cultures for enhanced efficiency of sorption and uptake of metals.

  3. Characterization of diazotrophic bacteria non-symbiotic associated with eucalyptus (eucalyptus sp.) in Codazzi, Cesar (Colombia)

    International Nuclear Information System (INIS)

    The effect of climatic seasons (rainy and dry) and the stratum sample (rhizospheric soil, roots and leaves) the population of the genera Azotobacter, Beijerinckia, Derxia, Azospirillum, Herbaspirillum, Gluconacetobacter and Burkholderia in soil rhizosphere, roots and leaves of eucalyptus (eucalyptus sp.). It also assesses their ability to produce indoles compounds as plant growth promoters and their acetylene reduction activity as an indicator of biological fixation of nitrogen. The results showed no statistically significant differences in the Duncan test (p ≤ 0.05) in the population with respect to the climate epoch, suggesting that these bacteria are able to tolerate stress conditions by different physiological mechanisms. With respect to the stratum sample isolates attempts of Herbaspirillum sp. and Azospirillum sp. significant differences in rhizospheric soil and roots. we obtained 44 isolates of which were grouped by phenotypic characterization as 14 suspected of Beijerinckia sp., 12 Azotobacter sp., 8 Derxia sp., 4 Herbaspirillum sp., 5 Azospirillum sp., 1 Gluconacetobacter sp. and 1 Burkholderia sp. due to their high potential were selected isolates C27, C26 and C25. These four strains present the best values of efficiency in vitro, exceeding production values of the reference strains used (A. chroococcum (AC1) and a. brasilense (SP7)).

  4. SEED INOCULATION WITH Azospirillum brasilense, ASSOCIATED WITH THE USE OF BIOREGULATORS IN MAIZE

    Directory of Open Access Journals (Sweden)

    ALESSANDRO DE LUCCA E BRACCINI

    2012-01-01

    Full Text Available The inoculation of seeds with the bacterium Azospirillum has been carried out in maize culture and other grasses. The application of growth bio-regulators is another technology whose results in maize culture have yet to become more widespread. Current study evaluates the agronomic effectiveness of seed inoculation with Azospirillum brasilense in maize, associated with the use of the growth regulator Stimulate ®. Triple hybrid maize CD 304 underwent the following treatments: 1 - control without nitrogen and without Azospirillum brasilense; 2 - Treatment without nitrogen but with Azospirillum brasilense; 3 - Treatment without nitrogen but with Azospirillum brasilense + Stimulate ®; 4 - Treatment with 50% of nitrogen dose recommended for maize culture; 5 - Treatment with 50% of nitrogen dose and inoculation with Azospirillum brasilense; 6 - Same as 5 but with Stimulate ®; 7 - Total N recommended; 8 - Total N recommended + Azospirillum brasilense ; 9 - Total N recommended + Azospirillum brasilense + Stimulate ®. The inoculation of maize seeds with Azospirillum brasilense increases plant height and grain yield when compared with rates in control. The use of 50% of N dose in sowing, associated with the inoculation of maize seeds with Azospirillum brasilense at 200 mL ha-1 (mixed to the seeds and associated with Stimulate ® (in foliar application, is viable.

  5. Inoculación con Azospirillum spp y Enterobacter aglomerans en Pasto Guinea (Panicum maximum Jacq. en el Departamento de Cesar (Colombia / Inoculation with Azospirillum spp and Enterobacter aglomerans in Guinea Grass (Panicum maximum Jacq. in the Cesar

    Directory of Open Access Journals (Sweden)

    Diana María Cárdenas Caro

    2014-06-01

    Full Text Available Resumen. Se evaluó el efecto de los aislados SRGM2, SRGM3 y SRGM4 de Azospirillum spp. en el crecimiento y desarrollo de plantas de pasto Guinea (Panicum maximum Jacq cv. Tanzania en la Estación Experimental Motilonia de Corpoica, del municipio Agustín Codazzi (Cesar, Colombia. Se realizó inoculación por imbibición de las semillas, y en el momento de la siembra, en las macetas en condiciones de casa malla. Se utilizó inoculación simple de los aislados de Azospirillum sp y co-inoculación con una cepa fosfato solubilizadora de Enterobacter aglomerans (UV1, aislada de suelos cultivados con algodón en el departamento de Cesar. Lasvariables estudiadas en las plantas fueron: germinación, peso foliar fresco y seco, peso radical fresco y seco, fósforo y proteína foliar. Los resultados mostraron que la inoculación simple y combinada promovió la germinación de semillas del pasto guinea (P≤0,05 con respecto al tratamiento sin inoculación (testigo absoluto; y aunque no se presentaron diferencias significativas (P≤0,05 en las demásvariables estudiadas, se encontraron aumentos de hasta 26,80% en proteína cruda, y 45,67% en materia seca foliar comparada con las plantas tratadas con 100% de fertilización nitrogenada. Se observó que el aislado de Azospirillum SRGM2 co-inoculado con Enterobacter aglomerans UV1 registró los mayores valores en el crecimiento vegetal del pasto guinea, por lo que se consideró como una rizobacteria promisoria para la biofertilización de esta gramínea utilizada en la alimentación bovina en la costa caribe colombiana. / Abstract. The effect of the isolates SRGM2, SRGM3 and SRGM of Azospirillum spp. on the growth and development of Guinea grass plants (Panicum maximum Jacq cv. Tanzania was evaluated in the Experimental Station Motilonia of Corpoica, municipality Agustin Codazzi (Cesar, Colombia. The inoculation was performed by imbibition of seeds and at planting time in pots under

  6. [Localization of denitrification genes in plasmid DNA of bacteria Azospirillum brasilense].

    Science.gov (United States)

    Petrova, L P; Varshalomidze, O É; Shelud'ko, A V; Katsy, E I

    2010-07-01

    In 85-Mda plasmid (p85) of plant-associated bacteria Azospirillum brasilense Sp245 model strain, the genes encoding copper-containing nitrite reductase (nirK); heterodimeric NO-reductase (norCB); NorQ and NorD proteins affecting synthesis and (or) activation of NirK and (or) NO-reductase (norQD); catalytic subunit I ofcytochrom c oxidase (CccoN); presumable NO sensor carrying two hemeerythrine domains (orf181); and an enzyme required for synthesis of presumable NO antagonist, homocystein (metC) were identified. In the same region of p85, orf293 encoding transcriptional regulator of LysR type, orf208 whose protein product carries a formylmethanofuran dehydrogenase subunit E domain, and an orf164-encoding conservative secretory protein with unknown function were also found. Localization of a set of denitrification genes in the plasmid DNA A. brasilense Sp245 adjacent to IS elements ISAzba1 and ISAzba2 indicates potential mobility of these genes and high probability of their horizontal transfer among populations of rhizospheric bacteria. A site homologous to p85 nirK-orf208-orf181 genes was detected in the 115 kb plasmid of A. brasilense Sp7 type strain.

  7. [Localization of denitrification genes in plasmid DNA of bacteria Azospirillum brasilense].

    Science.gov (United States)

    Petrova, L P; Varshalomidze, O É; Shelud'ko, A V; Katsy, E I

    2010-07-01

    In 85-Mda plasmid (p85) of plant-associated bacteria Azospirillum brasilense Sp245 model strain, the genes encoding copper-containing nitrite reductase (nirK); heterodimeric NO-reductase (norCB); NorQ and NorD proteins affecting synthesis and (or) activation of NirK and (or) NO-reductase (norQD); catalytic subunit I ofcytochrom c oxidase (CccoN); presumable NO sensor carrying two hemeerythrine domains (orf181); and an enzyme required for synthesis of presumable NO antagonist, homocystein (metC) were identified. In the same region of p85, orf293 encoding transcriptional regulator of LysR type, orf208 whose protein product carries a formylmethanofuran dehydrogenase subunit E domain, and an orf164-encoding conservative secretory protein with unknown function were also found. Localization of a set of denitrification genes in the plasmid DNA A. brasilense Sp245 adjacent to IS elements ISAzba1 and ISAzba2 indicates potential mobility of these genes and high probability of their horizontal transfer among populations of rhizospheric bacteria. A site homologous to p85 nirK-orf208-orf181 genes was detected in the 115 kb plasmid of A. brasilense Sp7 type strain. PMID:20795494

  8. [Comparative assessment of inductive effects of Azospirillum lectins with different antigenic properties on the signal systems of wheat seedling roots].

    Science.gov (United States)

    Alen'kina, S A; Petrova, L P; Sokolova, M K; Chernyshova, M P; Trutneva, K A; Bogatyrev, V A; Nikitina, V E

    2014-01-01

    The lectins of associative nitrogen-fixing bacteria Azospirillum brasilense Sp7 and its mutant A. brasilense Sp7.2.3 were shown to have different effects on the components of the wheat seedling root signal system, namely to regulate the levels of cAMP, nitric oxide, diacylglycerol, and salicylic acid, as well as to induce the activities of superoxide dismutase and lipoxygenase. Our results make it possible to consider azospirilla lectins as inducers of the signal systems in wheat seedling roots, since they cause development of several flows of primary signals. These data are of general biological importance, since lectins are present in all living organisms and most ot the functions of lectins remain insufficiently understood.

  9. Quantification of Azospirillum brasilense FP2 Bacteria in Wheat Roots by Strain-Specific Quantitative PCR.

    Science.gov (United States)

    Stets, Maria Isabel; Alqueres, Sylvia Maria Campbell; Souza, Emanuel Maltempi; Pedrosa, Fábio de Oliveira; Schmid, Michael; Hartmann, Anton; Cruz, Leonardo Magalhães

    2015-10-01

    Azospirillum is a rhizobacterial genus containing plant growth-promoting species associated with different crops worldwide. Azospirillum brasilense strains exhibit a growth-promoting effect by means of phytohormone production and possibly by N2 fixation. However, one of the most important factors for achieving an increase in crop yield by plant growth-promoting rhizobacteria is the survival of the inoculant in the rhizosphere, which is not always achieved. The objective of this study was to develop quantitative PCR protocols for the strain-specific quantification of A. brasilense FP2. A novel approach was applied to identify strain-specific DNA sequences based on a comparison of the genomic sequences within the same species. The draft genome sequences of A. brasilense FP2 and Sp245 were aligned, and FP2-specific regions were filtered and checked for other possible matches in public databases. Strain-specific regions were then selected to design and evaluate strain-specific primer pairs. The primer pairs AzoR2.1, AzoR2.2, AzoR5.1, AzoR5.2, and AzoR5.3 were specific for the A. brasilense FP2 strain. These primer pairs were used to monitor quantitatively the population of A. brasilense in wheat roots under sterile and nonsterile growth conditions. In addition, coinoculations with other plant growth-promoting bacteria in wheat were performed under nonsterile conditions. The results showed that A. brasilense FP2 inoculated into wheat roots is highly competitive and achieves high cell numbers (∼10(7) CFU/g [fresh weight] of root) in the rhizosphere even under nonsterile conditions and when coinoculated with other rhizobacteria, maintaining the population at rather stable levels for at least up to 13 days after inoculation. The strategy used here can be applied to other organisms whose genome sequences are available.

  10. Population dynamics and identification of efficient strains of Azospirillum in maize ecosystems of Bihar (India).

    Science.gov (United States)

    Verma, Rinkee; Chourasia, S K; Jha, M N

    2011-12-01

    Information on inoculum load and diversity of native microbial community is an important prerequisite for crop management of microbial origin. Azospirillum has a proven role in benefiting the maize (Zea mays) crop in terms of nutrient (nitrogen) supply as well as plant growth enhancement. Bihar state has highest average national maize productivity although fertilizer consumption is minimum, indicating richness of Azospirillum both in terms of population and diversity in soils. An experiment was planned to generate basic information on Azospirillum population variation in maize soils under different agricultural practices and soil types of Bihar, to identify suitable agricultural practices supporting the target microorganism and efficient Azospirillum strain(s). No tillage, growing traditional maize cultivar, land use history (diara soil having history of maize cultivation), soil organic carbon (>1%) and intercrop with oat supported prevalence of Azospirillum in maize rhizosphere. Native Azospirillum population varied from 1 million to 1 billion/g soil under diverse agricultural practices and soil types. Such richness, however, does not necessarily mean that artificial inoculation of Azospirillum is not required in Bihar soils as 92% of Azospirillum isolates (50 isolates) were poor in nitrogen-fixing ability and 88% were poor on IAA production. Efficient strains of Azospirillum based on growth (three), acetylene reduction assay (three), IAA production (three), broad range of pH (two) and temperature tolerance were identified. The findings suggested that maize crop in Bihar should be inoculated in universal mode rather than site-specific mode. PMID:22558543

  11. An extra-cytoplasmic function sigma factor and anti-sigma factor control carotenoid biosynthesis in Azospirillum brasilense.

    Science.gov (United States)

    Thirunavukkarasu, Nagarajan; Mishra, Mukti Nath; Spaepen, Stijn; Vanderleyden, Jos; Gross, Carol A; Tripathi, Anil K

    2008-07-01

    Strains Sp7 and Cd of Azospirillum brasilense, a plant growth-promoting rhizobacterium, differ in synthesis of carotenoids. While colonies of strain Sp7 have a white-cream colour on plates, colonies of strain Cd are orange-pink coloured because of the synthesis of carotenoids. Screening of a mini-Tn5 mutant library of A. brasilense Sp7 revealed two orange-pink-coloured mutants that produced carotenoids. Cloning and sequencing of the Tn5 flanking region in both the carotenoid-producing mutants of Sp7 revealed insertion of Tn5 in an ORF encoding anti-sigma factor, a ChrR-like protein. The upstream region of the Tn5-mutated ORF contained another ORF that encoded an extra-cytoplasmic function (ECF)-class sigma factor (sigma(E), RpoE). When the nucleotide sequences of the corresponding ORFs from the carotenoid-producing strain Cd were analysed, the sequence of the Cd sigma(E) was identical to that of the carotenoid non-producing strain Sp7, but the Cd anti-sigma(E) ORF had a deletion that caused frame shifting and creation of a stop codon. This resulted in the premature termination of the protein, which was about 7 kDa smaller than the Sp7 anti-sigma(E). Cloning of Sp7 anti-sigma(E) in a broad-host-range expression vector and expression in A. brasilense Cd and in the anti-sigma(E) knockout mutant of A. brasilense Sp7 resulted in the inhibition of carotenoid synthesis. Similarly, cloning and overexpression of A. brasilense Sp7 sigma(E) in A. brasilense Sp7 resulted in the production of carotenoids. These observations clearly indicate that carotenoid synthesis in A. brasilense is controlled by sigma(E) with its cognate anti-sigma(E).

  12. Electro-optical study of the exposure of Azospirillum brasilense carbohydrate epitopes.

    Science.gov (United States)

    Guliy, Olga I; Matora, Larisa Yu; Dykman, Lev A; Staroverov, Sergey A; Burygin, Gennady L; Bunin, Viktor D; Burov, Andrei M; Ignatov, Oleg V

    2015-01-01

    The exposure of Azospirillum brasilense carbohydrate epitopes was investigated by electro-optical analysis of bacterial cell suspensions. To study changes in the electro-optical (EO) properties of the suspensions, we used antibodies generated to the complete lipopolysaccharide of A. brasilense type strain Sp7 and also antibodies to the smooth and rough O polysaccharides of Sp7. After 18 hr of culture growth, the EO signal of the suspension treated with antibodies to smooth O polysaccharide was approximately 20% lower than that of the suspension treated with antibodies to complete lipopolysaccharide (control). After 72 hr of culture growth, the strongest EO signal was observed for the cells treated with antibodies to rough O polysaccharide (approximately 46% greater than the control), whereas for the cells treated with antibodies to smooth O polysaccharide, it was much lower (approximately 23% of the control). These data were confirmed by electron microscopy. The results of the study may have importance for the rapid evaluation of changes in lipopolysaccharide form in microbial biotechnology, when the antigenic composition of the bacterial surface requires close control.

  13. Biofilm formation by Azospirillum brasilense: microbial socialization in the rhizosphere

    OpenAIRE

    Cerqueira, Francisco Diogo de Almeida, 1990-

    2015-01-01

    Tese de mestrado. Biologia (Microbiologia Aplicada). Universidade de Lisboa, Faculdade de Ciências, 2014 Azospirillum brasilense is a remarkable Plant-Growth Promoting Rhizobacteria (PGPR), with great potential as agricultural inoculant for several crops. Several isolates of this species have been produced as inoculant by some companies and applied in the agriculture as a biofertilizer. Therefore, there is a great interest in gathering more scientific knowledge that improves A. brasilense ...

  14. Inoculation of maize with Azospirillum brasilense in the seed furrow

    Directory of Open Access Journals (Sweden)

    Tâmara Prado de Morais

    2016-06-01

    Full Text Available ABSTRACT Several studies addressing the inoculation of cereals with diazotrophic microorganisms can be found in the literature. However, in many experiments, investigators have overlooked the feasibility of applying these microorganisms to the furrow together with the seed, and the effect of bacterial concentration on phytostimulation. The aim of this work was to evaluate the effect of doses of an inoculant based on Azospirillum brasilense, applied to the seed furrow when planting maize, combined with different doses of nitrogen fertiliser. The experiment was carried out in the field, in soil of the cerrado region of Brazil. An experimental design of randomised blocks in bands was adopted, comprising nitrogen (40, 100, 200 and 300 kg ha-1 and doses of an A. brasilense-based liquid inoculant applied to the seed furrow (0, 100, 200, 300 and 400 mL ha-1. The dose of 200 mL ha-1Azospirillum was noteworthy for grain production. This is the first report of the effective application of Azospirillum in the seed furrow when planting maize in the cerrado region of Brazil.

  15. Effects of saline tolerant Azospirillum species on the growth parameters of mangrove seedlings.

    Science.gov (United States)

    Ravikumar, S; Ignatiammal, S Thadedus Maria; Gnanadesigan, M; Kalaiarasi, A

    2012-09-01

    Five species of Azospirillum isolated from Manakkudi mangrove ecosystem were subjected for their efficiency to find out their growth parameters potential for the successful establishment of mangrove seedlings. Of the isolated five Azospirillum species, Azospirillum lipoferum (60%) was found to be the dominant one. But the level of maximum indole acetic acid (IAA) production (19.8 mg.ml(-1)) and nitrogen fixation (5.9 C2H2hr1) was identified with A. brasilense. Further, A. brasilense showed significant (p brasilense also showed significant (p Azospirillum brasilense was found better for the growth of Avicennia officinalis and Ceriops decandra seedlings, but Azospirillum irakense was found better for Rhizophora apiculata seedlings.

  16. Gold(III) reduction by the rhizobacterium Azospirillum brasilense with the formation of gold nanoparticles.

    Science.gov (United States)

    Tugarova, Anna V; Burov, Andrei M; Burashnikova, Marina M; Kamnev, Alexander A

    2014-01-01

    For the soil nitrogen-fixing bacterium Azospirillum brasilense, the ability to reduce [AuCl4](-) and to form gold nanoparticles (GNPs) has been demonstrated, with the appearance of a mauve tint of the culture. To validate the shapes and chemical nature of nanoparticles, transmission electron microscopy (TEM) and X-ray fluorescence analysis were used. For the widely studied agriculturally important wild-type strains A. brasilense Sp7 and Sp245, GNPs formed after 10 days of incubation of cell biomass with 0.25 mM [AuCl4](-) were shown (using TEM) to be mainly of spherical form (5 to 20 nm in diameter), with rare occasional triangles. In the course of cultivation with [AuCl4](-), after 5 days, a mauve tint was already visible for cells of strain Sp245.5, after 6 days for Sp245 and after 10 days for Sp7. Thus, for the mutant strain Sp245.5 (which has significant differences in the structure and composition of cell-surface polysaccharides as compared with Sp245), a more rapid formation of GNPs was observed. Moreover, their TEM images (also obtained after 10 days) showed different shapes: nano-sized spheres, triangles, hexagons and rods, as well as larger round-shaped flower-like nanoparticles about 100 nm in size. Since by the time of GNP formation in our experiments the cells were found to be already not viable, this confirms the dominating role of cell surface structure and chemical composition in shaping the GNPs formed in the course of [AuCl4](-) reduction to Au(0). This finding may be useful for understanding the natural biogeochemical mechanisms of gold reduction and formation of GNPs involving microorganisms. The data obtained may also help in developing protocols for environmentally friendly synthesis of nanoparticles and possible use of bacterial cells with modified surface structure and composition for their fabrication.

  17. Spectroscopic characterization of cell membranes and their constituents of the plant-associated soil bacterium Azospirillum brasilense

    Science.gov (United States)

    Kamnev, A. A.; Antonyuk, L. P.; Matora, L. Yu.; Serebrennikova, O. B.; Sumaroka, M. V.; Colina, M.; Renou-Gonnord, M.-F.; Ignatov, V. V.

    1999-05-01

    Structural and compositional features of bacterial membranes and some of their isolated constituents (cell surface lipopolysaccharide, phospholipids) of the plant-growth-promoting diazotrophic rhizobacterium Azospirillum brasilense (wild-type strain Sp245) were characterized using Fourier transform infrared (FTIR) spectroscopy and some other techniques. FTIR spectra of the cell membranes were shown to comprise the main vibration modes of the relevant lipopolysaccharide and protein components which are believed to be involved in associative plant-bacterium interactions, as well as of phospholipid constituents. The role and functions of metal cations in the structural organization and physicochemical properties of bacterial cell membranes are also discussed considering their accumulation in the membranes from the culture medium.

  18. [Diverse morphological types of dormant cells and conditions for their formation in Azospirillum brasilense].

    Science.gov (United States)

    Muliukin, A L; Suzina, N E; Pogorelova, A Iu; Antoniuk, L P; Duda, V I; El'-Registan, G I

    2009-01-01

    Differences in generation of dormant forms (DF) were revealed between two strains of non-sporeforming gram-negative bacteria Azospirillum brasilense, Sp7 (non-endophytic) and Sp245 (endophytic strain). In post-stationary ageing bacterial cultures grown in a synthetic medium with a fivefold decreased initial nitrogen content, strain Sp7 formed two types of cyst-like resting cells (CRC). Strain Sp245 did not form such types of DF under the same conditions. CRC of the first type were formed in strain Sp245 only under phosphorus deficiency (C > P). The endophytic strain was also shown to form structurally differentiated cells under complete starvation, i.e. at a transfer of early stationary cultures, grown in the media with C > N unbalance, to saline solution (pH 7.2). These DF had a complex structure similar to that of azotobacter cysts. The CRC, which are generated by both azospirilla strains and belong to distinct morphological types, possessed the following major features: absence of division; specific ultrastructural organization; long-term maintenance of viability (for 4 months and more); higher heat resistance (50-60 degrees C, 10 min) as compared with vegetative cells, i.e. the important criteria for dormant prokaryotic forms. However, CRC of non-endophytic strain Sp7 had higher heat resistance (50, 55, 60 degrees C). The viability maintenance and the portion of heat-resistant cells depended on the conditions of maturation and storage of CRC populations. Long-term storage (for 4 months and more) of azospirilla DF populations at -20 degrees C was optimal for maintenance of their colony-forming ability (57% of the CFU number in stationary cultures), whereas the largest percentage of heat-resistant cells was in CRC suspensions incubated in a spent culture medium (but not in saline solution) at room temperature. The data on the intraspecies diversity of azospirilla DF demonstrate the relation between certain type DF formation to the type of interaction (non

  19. The cyclic-di-GMP diguanylate cyclase CdgA has a role in biofilm formation and exopolysaccharide production in Azospirillum brasilense.

    Science.gov (United States)

    Ramírez-Mata, Alberto; López-Lara, Lilia I; Xiqui-Vázquez, Ma Luisa; Jijón-Moreno, Saúl; Romero-Osorio, Angelica; Baca, Beatriz E

    2016-04-01

    In bacteria, proteins containing GGDEF domains are involved in production of the second messenger c-di-GMP. Here we report that the cdgA gene encoding diguanylate cyclase A (CdgA) is involved in biofilm formation and exopolysaccharide (EPS) production in Azospirillum brasilense Sp7. Biofilm quantification using crystal violet staining revealed that inactivation of cdgA decreased biofilm formation. In addition, confocal laser scanning microscopy analysis of green-fluorescent protein-labeled bacteria showed that, during static growth, the biofilms had differential levels of development: bacteria harboring a cdgA mutation exhibited biofilms with considerably reduced thickness compared with those of the wild-type Sp7 strain. Moreover, DNA-specific staining and treatment with DNase I, and epifluorescence studies demonstrated that extracellular DNA and EPS are components of the biofilm matrix in Azospirillum. After expression and purification of the CdgA protein, diguanylate cyclase activity was detected. The enzymatic activity of CdgA-producing cyclic c-di-GMP was determined using GTP as a substrate and flavin adenine dinucleotide (FAD(+)) and Mg(2)(+) as cofactors. Together, our results revealed that A. brasilense possesses a functional c-di-GMP biosynthesis pathway.

  20. APPLICATION TIMES OF AN Azospirillum BIOPRODUCT IN TOMATO GROWTH, DEVELOPMENT AND YIELD

    Directory of Open Access Journals (Sweden)

    Elein Terry

    2000-01-01

    Full Text Available Con el objetivo de estudiar diferentes momentos de aplicación de un bioproducto a base de Azospirillum brasilense Sp-7 en el cultivo del tomate, se desarrolló un experimento de campo durante dos años sobre un suelo Ferralítico Rojo compactado, realizándose el trabajo en dos etapas: fase de semillero y fase de floración-fructificación, teniéndose en cuenta un total de cinco tratamientos distribuidos completamente aleatorizados en la fase de semillero y bloques al azar en la fase de trasplante. Los resultados mostraron una respuesta positiva a la inoculación de esta rizobacteria en combinación con el fertilizante nitrogenado, manifestado a través del vigor y rendimiento alcanzado por las plantas. Desde el punto de vista de la viabilidad en el manejo y la factibilidad económica, la inoculación en el momento de la siembra resultó ser la más ventajosa.

  1. Sequencing and complementation analysis of the nifUSV genes from Azospirillum brasilense.

    Science.gov (United States)

    Frazzon, J; Schrank, I S

    1998-02-15

    The functionality of nitrogenase in diazotrophic bacteria is dependent upon nif genes other than the structural nifH, D, and K genes which encode the enzyme subunit proteins. Such genes are involved in the activation of nif gene expression, maturation of subunit proteins, cofactor biosynthesis, and electron transport. In this work, approximately 5500 base pairs located within the major nif gene cluster of Azospirillum brasilense Sp7 have been sequenced. The deduced open reading frames were compared to the nif gene products of Azotobacter vinelandii and other diazotrophs. This analysis indicates the presence of five ORFs encoding ORF2, nifU, nifS, nifV, and ORF4 in the same sequential organization as found in other organisms. Consensus sigma 54 and NifA binding sites are present in the putative promoter region upstream of ORF2 in the A. brasilense sequence. The nifV gene of A. brasilense but not nifU or nifS complemented corresponding mutants strains of A. vinelandii. PMID:9503607

  2. Extracellular polysaccharide composition of Azospirillum brasilense and its relation with cell aggregation.

    Science.gov (United States)

    Burdman, S; Jurkevitch, E; Soria-Díaz, M E; Serrano, A M; Okon, Y

    2000-08-15

    The exopolysaccharide (EPS) and capsular polysaccharide (CPS) composition of four Azospirillum brasilense strains differing in their aggregation capacity was analyzed by high performance anion exchange chromatography. When growing the different strains in an aggregation inducing medium containing a high carbon:nitrogen (C:N) ratio, both EPS and CPS showed a positive correlation between aggregation and the relative amount of arabinose. Arabinose was not detected in polysaccharides from Sp72002, a pleiotrophic Tn5 mutant strain impaired in aggregation. Arabinose was also not detected in extracellular polysaccharides of bacteria grown in a low C:N ratio, non-inducing aggregation medium, with exception for a relatively small amount found in the CPS of FAJ0204, a super-aggregating mutant strain. The only monosaccharides able to significantly inhibit aggregation at low sugar concentration when tested in a bioassay were arabinose (at a higher extent) and galactose. The possibility that residues of arabinose present in the extracellular polysaccharides are involved in the aggregation of A. brasilense is discussed.

  3. Strain-specific salt tolerance and osmoregulatory mechanisms in Azospirillum brasilense.

    Science.gov (United States)

    Chowdhury, Soumitra Paul; Nagarajan, Thirunavukkarasu; Tripathi, Rachna; Mishra, Mukti Nath; Le Rudulier, Daniel; Tripathi, Anil Kumar

    2007-02-01

    Salinity stress inhibits the growth and nitrogen fixation ability of the plant growth-promoting rhizobacterium Azospirillum brasilense. Five strains of A. brasilense were isolated from the rhizosphere of Indian cereals and grasses and identified on the basis of their phenotypic features and 16S rRNA gene sequence. The five Indian isolates and two standard strains of A. brasilense, Sp7 and Cd, showed notable differences in growth, acetylene-reducing activity under salt stress, and ability to take up and use glycine betaine for the restoration of growth and acetylene-reducing activity under salt stress. Salt stress also enhanced the production of exopolysaccharides and cell aggregates, the extent of which varied in different strains of A. brasilense at different carbon to nitrogen ratios in the culture medium. It can be concluded that the production of exopolysaccharides and cell aggregates is a more consistent physiological response of A. brasilense to salt stress than is the uptake and osmoprotection by glycine betaine.

  4. Plant yield and nitrogen content of a digitgrass in response to azospirillum inoculation

    Energy Technology Data Exchange (ETDEWEB)

    Schank, S.C.; Weier, K.L.; MacRae, I.C.

    1981-02-01

    Two Australian soils, a vertisol (pH 6.8, 0.299% N) and a sandy yellow podzol (pH 6.2, 0.042% N), were used with digitgrass, Digitaria sp. X46-2 (PI 421785), in a growth room experiment. Comparisons were made between plants inoculated with live and autoclaved bacterial suspensions of Australian and Brazilian isolates of Azospirillum brasilense. Seedlings were inoculated on days 10 and 35. Acetylene-reducing activity was measured five times during the experiment. Dry matter yields of the digitgrass on the podzol (low N) inoculated with liver bacteria were 23% higher than those of the controls. On the vertisol (high N), yield increases from inoculation with live bacteria were 8.5%. The higher-yielding plants had significantly lower precent nitrogen, but when total nitrogen of the tops was calculated, the inoculated plants had a higher total N than did the controls (P = 0.04). Acetylene-reducing activity was variable in the experiment, ranging from 0.5 to 11.9 mu mol of C2H2 core -1 day -1. Live bacterial treatment induced a proliferation of roots, possible earlier maturity, higher percent dry matter, and a higher total N in the tops. (Refs. 21).

  5. Mode of utilization of amino acids as growth substrates by Azospirillum brasilense.

    Science.gov (United States)

    Bhattacharya, Pradip

    2005-12-01

    The study was undertaken to analyze the rate of uptake and utilization of various amino acids by Azospirillum brasilense Sp81 (RG) in a basal mineral salts solution under non-nitrogen fixing condition. These amino acids including other nitrogenous compounds were tested for both N- and C-sources. The kinetic constants (Km and Vmax) of uptake of some amino acids (e.g. lysine, arginine, proline, glutamine and glutamic acid) were exploited using a Hanes-Woolf plot, and discussed in the context of nitrogen starvation or both carbon and nitrogen starvation. To summarize all the kinetic data for these amino acids strongly suggested that the mode of these amino acids utilization in this bacterium followed the same general pattern, although the quantitative differences were there. A single amino acid was able to satisfy the nitrogen needs of this bacterium in basal mineral salts solution, and this possibility could be considered for the cost-effective growth medium for this bacterium in the biotechnological industry.

  6. Population dynamics of free living, nitrogen fixing bacteria Azospirillum in Manakkudi mangrove ecosystem, India.

    Science.gov (United States)

    Ravikumar, S; Gnanadesigan, M; Ignatiammal, S Thadedus Maria; Sumaya, S

    2012-05-01

    Seasonal variations of population dynamics of free living nitrogen fixing bacteria, Azospirillum in relation to chemical parameters in Manakkudi mangrove ecosystem was assessed in root and rhizosphere soil samples of mangroves and mangrove associated plants. In rhizosphere soil and root samples, the counts of Azospirillum were recorded maximum in Acrostichum aureum as 8.63 +/- 0.92 x 10(4) and 115.48 +/- 17.36 x 10(4) CFU g(-1), respectively. The counts of Azospirillum in non-rhizosphere soil varied from 0.01 +/- 0.001 x 10(4) to 5.77 +/- 0.92 x 10(4) CFU g(-1) and found maximum in February and minimum in March and September. Azospirillum counts in water samples were found maximum (2.24 x 10(4) CFU l(-1)) in February. During seasonal variations maximum counts of Azospirillum were recorded during southwest monsoon season in Avicennia officinalis (1.40 x 10(4) CFU g(-1)) followed by Rhizophora mucronata (1.07 x 10(4) CFU g(-1)). The average maximum population density of Azospirillum counts was found during non monsoon season (9.73 x 10(4) CFU g(-1)) and the average maximum population density of Azospirillum counts was found with the mangrove associated root samples (13.73 x 10(4) CFU g(-1)). Of the selected isolates Azospirillum lipoferum (60%) was found to be predominant followed by Azospirillum brasilense (25%), Azospirillum irakense (5%), Azospirillum halopraeferens (5%) and Azospirillum amazonense (5%). Of the isolated species, A. halopraeferens exhibited better growth at 35 g l(-1) NaCl. The level of Fe, Cu, Zn and Mn were varied from 0.91 to 15.93 ppm. The level of Mn (12.13 ppm) was found maximum during non-monsoon of rhizosphere soil sample. Highest rainfall (192.80 mm) and atmospheric temperature (25.10 degrees C) were recorded during south west monsoon and non monsoon seasons. The increased population density was greatly influenced by the pH (r = +0.686). The present finding provides enough information on the nitrogen flow through biological process in

  7. Change in the Content of Salicylic Acid and in the Activities of Phenylalanine Ammonia-Lyase and Catalase in Wheat Seedling Roots Under the Effect of Azospirillum Lectins

    Directory of Open Access Journals (Sweden)

    Alen'kina S.A.

    2012-05-01

    Full Text Available We investigated the time course of changes in the endogenous content of salicylic acid, the ratio between the acid's free and bound forms, and changes in the activities of phenylalanine ammonia-lyase and catalase in wheat seedling roots under the effect of the lectins of two strains of the associative nitrogen-fixing bacterium Azospirillum: A. brasilense Sp7 and its mutant defective in lectin activity, A. brasilense Sp7.2.3. Differences in plant response to the action of the lectins from these two strains were established. On the basis of the obtained data, a model was proposed for lectin-assisted induction of resistance, according to which the lectin effect on the roots of seedlings results in accumulation of free salicylic acid, which inhibits catalase activity, ultimately leading to accumulation of hydrogen peroxide and to formation of induced resistance.

  8. Azospirillum genomes reveal transition of bacteria from aquatic to terrestrial environments.

    Directory of Open Access Journals (Sweden)

    Florence Wisniewski-Dyé

    2011-12-01

    Full Text Available Fossil records indicate that life appeared in marine environments ∼3.5 billion years ago (Gyr and transitioned to terrestrial ecosystems nearly 2.5 Gyr. Sequence analysis suggests that "hydrobacteria" and "terrabacteria" might have diverged as early as 3 Gyr. Bacteria of the genus Azospirillum are associated with roots of terrestrial plants; however, virtually all their close relatives are aquatic. We obtained genome sequences of two Azospirillum species and analyzed their gene origins. While most Azospirillum house-keeping genes have orthologs in its close aquatic relatives, this lineage has obtained nearly half of its genome from terrestrial organisms. The majority of genes encoding functions critical for association with plants are among horizontally transferred genes. Our results show that transition of some aquatic bacteria to terrestrial habitats occurred much later than the suggested initial divergence of hydro- and terrabacterial clades. The birth of the genus Azospirillum approximately coincided with the emergence of vascular plants on land.

  9. Azospirillum genomes reveal transition of bacteria from aquatic to terrestrial environments.

    OpenAIRE

    Florence Wisniewski-Dyé; Kirill Borziak; Gurusahai Khalsa-Moyers; Gladys Alexandre; Sukharnikov, Leonid O.; Kristin Wuichet; Gregory B Hurst; W Hayes McDonald; Robertson, Jon S.; Valérie Barbe; Alexandra Calteau; Zoé Rouy; Sophie Mangenot; Claire Prigent-Combaret; Philippe Normand

    2011-01-01

    International audience Fossil records indicate that life appeared in marine environments ∼3.5 billion years ago (Gyr) and transitioned to terrestrial ecosystems nearly 2.5 Gyr. Sequence analysis suggests that "hydrobacteria" and "terrabacteria" might have diverged as early as 3 Gyr. Bacteria of the genus Azospirillum are associated with roots of terrestrial plants; however, virtually all their close relatives are aquatic. We obtained genome sequences of two Azospirillum species and analyze...

  10. Population dynamics and identification of efficient strains of Azospirillum in maize ecosystems of Bihar (India)

    OpenAIRE

    Verma, Rinkee; Chourasia, S. K.; Jha, M. N.

    2011-01-01

    Information on inoculum load and diversity of native microbial community is an important prerequisite for crop management of microbial origin. Azospirillum has a proven role in benefiting the maize (Zea mays) crop in terms of nutrient (nitrogen) supply as well as plant growth enhancement. Bihar state has highest average national maize productivity although fertilizer consumption is minimum, indicating richness of Azospirillum both in terms of population and diversity in soils. An experiment w...

  11. Interaction of Azospirillum brasilense and Glomus intrarradix in Sugar Cane Roots

    OpenAIRE

    Bellone, Carlos H.; de Bellone Silvia, Carrizo

    2011-01-01

    Fifteen-day-old variety NA 56-79 sugar cane seedlings were inoculated with Azospirillum brasilense and Glomus intrarradix. This article aims at examining changes in sugar cane root seedlings inoculated with Glomus intrarradix and Azospirillum brasilense, the increase in microbial biomass and the acetylene reduction process as well. The internal root colonization was studied 20 days after inoculation using scanning and a transmission electron microscope. Both microorganisms entered the sugar c...

  12. Wheat root colonization and nitrogenase activity by Azospirillum isolates from crop plants in Korea.

    Science.gov (United States)

    Kim, Chungwoo; Kecskés, Mihály L; Deaker, Rosalind J; Gilchrist, Kate; New, Peter B; Kennedy, Ivan R; Kim, Seunghwan; Sa, Tongmin

    2005-11-01

    Nitrogen-fixing bacteria were isolated from the rhizosphere of different crops of Korea. A total of 16 isolates were selected and characterized. Thirteen of the isolates produced characteristics similar to those of the reference strains of Azospirillum, and the remaining 3 isolates were found to be Enterobacter spp. The isolates could be categorized into 3 groups based on their ARDRA patterns, and the first 2 groups comprised Azospirillum brasilense and Azospirillum lipoferum. The acetylene reduction activity (ARA) of these isolates was determined for free cultures and in association with wheat roots. There was no correlation between pure culture and plant-associated nitrogenase activity of the different strains. The isolates that showed higher nitrogenase activities in association with wheat roots in each group were selected and sequenced. Isolates of Azospirillum brasilense CW301, Azospirillum brasilense CW903, and Azospirillum lipoferum CW1503 were selected to study colonization in association with wheat roots. We observed higher expression of beta-galactosidase activity in A. brasilense strains than in A. lipoferum strains, which could be attributed to their higher population in association with wheat roots. All strains tested colonized and exhibited the strongest beta-galactosidase activity at the sites of lateral roots emergence.

  13. Effects of heavy metals on plant-associated rhizobacteria: comparison of endophytic and non-endophytic strains of Azospirillum brasilense.

    Science.gov (United States)

    Kamnev, Alexander A; Tugarova, Anna V; Antonyuk, Lyudmila P; Tarantilis, Petros A; Polissiou, Moschos G; Gardiner, Philip H E

    2005-01-01

    The plant-associated nitrogen-fixing rhizobacterium Azospirillum brasilense attracts world-wide attention owing to its plant growth-promoting activities. Among hundreds of its strains known up to date, wild-type strain Sp245 has been proved to be capable of colonising both the plant-root interior and exterior (i.e. a facultative endophyte), whereas others are non-endophytes colonising the root surface only. Thus, the different ecological niches occupied by these strains in the rhizosphere suggest that their responses to environmental conditions might differ as well. In this study, responses of A. brasilense strains Sp245 and Sp7 to several heavy metals (Co2+, Cu2+, Zn2+), present in the medium at tolerable concentrations (up to 0.2 mmol/l) and taken up by the bacteria, were compared. Fourier transform infrared (FTIR) spectroscopy was used for controlling the compositional features of whole cells. The results obtained show that in strain Sp7 (non-endophyte) the heavy metals induced an enhanced accumulation of polyester compounds (poly-3-hydroxybutyrate; PHB). In contrast, the response of the endophytic strain Sp245 to heavy metal uptake was found to be much less pronounced. These dissimilarities in their behaviour may be caused by different adaptation abilities of these strains to stress conditions owing to their different ecological status. It was also found that adding 0.2 mmol/l Cu2+ or Cd2+ in the culture medium resulted in noticeably reducing the levels of indole-3-acetic acid (IAA, auxin) produced by both the strains of the bacterium. This can directly affect the efficiency of associative plant-bacterial symbioses involving A. brasilense in heavy-metal-contaminated soil.

  14. Phenotypical and molecular responses of Arabidopsis thaliana roots as a result of inoculation with the auxin-producing bacterium Azospirillum brasilense.

    Science.gov (United States)

    Spaepen, Stijn; Bossuyt, Stijn; Engelen, Kristof; Marchal, Kathleen; Vanderleyden, Jos

    2014-02-01

    The auxin-producing bacterium Azospirillum brasilense Sp245 can promote the growth of several plant species. The model plant Arabidopsis thaliana was chosen as host plant to gain an insight into the molecular mechanisms that govern this interaction. The determination of differential gene expression in Arabidopsis roots after inoculation with either A. brasilense wild-type or an auxin biosynthesis mutant was achieved by microarray analysis. Arabidopsis thaliana inoculation with A. brasilense wild-type increases the number of lateral roots and root hairs, and elevates the internal auxin concentration in the plant. The A. thaliana root transcriptome undergoes extensive changes on A. brasilense inoculation, and the effects are more pronounced at later time points. The wild-type bacterial strain induces changes in hormone- and defense-related genes, as well as in plant cell wall-related genes. The A. brasilense mutant, however, does not elicit these transcriptional changes to the same extent. There are qualitative and quantitative differences between A. thaliana responses to the wild-type A. brasilense strain and the auxin biosynthesis mutant strain, based on both phenotypic and transcriptomic data. This illustrates the major role played by auxin in the Azospirillum-Arabidopsis interaction, and possibly also in other bacterium-plant interactions.

  15. Effects of Azospirillum brasilense with genetically modified auxin biosynthesis gene ipdC upon the diversity of the indigenous microbiota of the wheat rhizosphere.

    Science.gov (United States)

    Baudoin, Ezékiel; Lerner, Anat; Mirza, M Sajjad; El Zemrany, Hamdy; Prigent-Combaret, Claire; Jurkevich, Edouard; Spaepen, Stijn; Vanderleyden, Jos; Nazaret, Sylvie; Okon, Yaacov; Moënne-Loccoz, Yvan

    2010-04-01

    The phytostimulatory properties of Azospirillum inoculants, which entail production of the phytohormone indole-3-acetic acid (IAA), can be enhanced by genetic means. However, it is not known whether this could affect their interactions with indigenous soil microbes. Here, wheat seeds were inoculated with the wild-type strain Azospirillum brasilense Sp245 or one of three genetically modified (GM) derivatives and grown for one month. The GM derivatives contained a plasmid vector harboring the indole-3-pyruvate/phenylpyruvate decarboxylase gene ipdC (IAA production) controlled either by the constitutive promoter PnptII or the root exudate-responsive promoter PsbpA, or by an empty vector (GM control). All inoculants displayed equal rhizosphere population densities. Only inoculation with either ipdC construct increased shoot biomass compared with the non-inoculated control. At one month after inoculation, automated ribosomal intergenic spacer analysis (ARISA) revealed that the effect of the PsbpA construct on bacterial community structure differed from that of the GM control, which was confirmed by 16S rDNA-based denaturing gradient gel electrophoresis (DGGE). The fungal community was sensitive to inoculation with the PsbpA construct and especially the GM control, based on ARISA data. Overall, fungal and bacterial communities displayed distinct responses to inoculation of GM A. brasilense phytostimulators, whose effects could differ from those of the wild-type.

  16. Phenotypic variation in Azospirillum brasilense exposed to starvation.

    Science.gov (United States)

    Lerner, Anat; Valverde, Angel; Castro-Sowinski, Susana; Lerner, Hadas; Okon, Yaacov; Burdman, Saul

    2010-08-01

    Bacteria have developed mechanisms that allow them maintaining cell viability during starvation and resuming growth when nutrients become available. Among these mechanisms are adaptive mutations and phase variation, which are often associated with DNA rearrangements. Azospirillum brasilense is a Gram-negative, nitrogen-fixing, plant growth-promoting rhizobacterium. Here we report phenotypic variants of A. brasilense that were collected after exposure to prolonged starvation or after re-isolation from maize roots. The variants differed in several features from the parental strains, including pigmentation, aggregation ability, EPS amount and composition and LPS structure. One of the phenotypic variants, overproducing EPS and showing an altered LPS structure, was further characterized and showed differential response to several stresses and antibiotics relative to its parental strain. Characterization of the variants by repetitive-PCR revealed that phenotypic variation was often associated with DNA rearrangements.

  17. Accessing inoculation methods of maize and wheat with Azospirillum brasilense.

    Science.gov (United States)

    Fukami, Josiane; Nogueira, Marco Antonio; Araujo, Ricardo Silva; Hungria, Mariangela

    2016-03-01

    The utilization of inoculants containing Azospirillum is becoming more popular due to increasing reports of expressive gains in grain yields. However, incompatibility with pesticides used in seed treatments represents a main limitation for a successful inoculation. Therefore, in this study we searched for alternatives methods for seed inoculation of maize and wheat, aiming to avoid the direct contact of bacteria with pesticides. Different doses of inoculants containing Azospirillum brasilense were employed to perform inoculation in-furrow, via soil spray at sowing and via leaf spray after seedlings had emerged, in comparison to seed inoculation. Experiments were conducted first under greenhouse controlled conditions and then confirmed in the field at different locations in Brazil. In the greenhouse, most parameters measured responded positively to the largest inoculant dose used in foliar sprays, but benefits could also be observed from both in-furrow and soil spray inoculation. However, our results present evidence that field inoculation with plant-growth promoting bacteria must consider inoculant doses, and point to the need of fine adjustments to avoid crossing the threshold of growth stimulation and inhibition. All inoculation techniques increased the abundance of diazotrophic bacteria in plant tissues, and foliar spray improved colonization of leaves, while soil inoculations favored root and rhizosphere colonization. In field experiments, inoculation with A. brasilense allowed for a 25 % reduction in the need for N fertilizers. Our results have identified alternative methods of inoculation that were as effective as the standard seed inoculation that may represent an important strategy to avoid the incompatibility between inoculant bacteria and pesticides employed for seed treatment.

  18. Hydrogenase activity in Azospirillum brasilense is inhibited by nitrite, nitric oxide, carbon monoxide, and acetylene

    Energy Technology Data Exchange (ETDEWEB)

    Tibelius, K.H.; Knowles, R.

    1984-10-01

    Nitrite, NO, CO, and C/sub 2/H/sub 2/ inhibited O/sub 2/-dependent H/sub 2/ uptake (H/sup 3/H oxidation) in denitrifying Azospirillum brasilense Sp7 grown anaerobically on N/sub 2/O or NO/sub 3//sup -/. The apparent K/sub i/ values for inhibition of O/sub 2/-dependent H/sub 2/ uptake were 20 ..mu..M for NO/sub 2//sup -/, 0.4 ..mu..M for NO, 28 ..mu..M for CO, and 88 ..mu..M for C/sub 2/H/sub 2/. These inhibitors also affected methylene blue-dependent H/sub 2/ uptake, presumably by acting directly on the hydrogenase. Nitrite and NO inhibited H/sub 2/ uptake irreversibly, whereas inhibition due to CO was easily reversed by repeatedly evacuating and backfilling with N/sub 2/. The C/sub 2/H/sub 2/ inhibition was not readily reversed, partly due to difficulty in removing the last traces of this gas from solution. The NO/sub 2//sup -/ inhibition of malate-dependent respiration was readily reversed by repeatedly washing the cells, in contrast to the effect of NO/sub 2//sup -/ on H/sub 2/-dependent respiration. These results suggest that the low hydrogenase activities observed in NO/sub 3//sup -/-grown cultures of A. brasilense may be due to the irreversible inhibition of hydrogenase by NO/sub 2//sup -/ and NO produced by NO/sub 3//sup -/ reduction.

  19. CARACTERIZACIÓN DE BACTERIAS DIAZOTRÓFICAS ASIMBIÓTICAS ASOCIADAS AL EUCALIPTO (Eucalyptus sp. EN CODAZZI, CESAR.

    Directory of Open Access Journals (Sweden)

    Divan Baldani Vera Lúcia

    2010-12-01

    Full Text Available Se evaluó el efecto de las épocas climáticas (lluvia y sequía y del estrato de la muestra (Suelo rizosférico, raíces y hojas sobre la población de los géneros Azotobacter, Beijerinckia, Derxia, Azospirillum, Herbaspirillum, Gluconacetobacter y Burkholderia en el Eucalipto (Eucalyptus sp.. Así mismo, se evalúo su capacidad en la producción de compuestos indólicos como promotores del crecimiento vegetal y su actividad de reducción de acetileno como indicador de la fijación biológica de nitrógeno. Los resultados no registraron diferencias estadísticas significativas en el test de Tukey (P ≤ 0.05 en la población con respecto a la época climática. Con respecto al estrato de muestra, los aislamientos tentativos a Herbaspirillum sp. y Azospirillum sp. presentaron diferencias significativas en suelo rizosférico y raíces. Se obtuvieron 44 aislamientos de los cuales se agruparon por caracterización fenotípica como: 14 presuntivos del género Beijerinckia sp., 12 de Azotobacter sp., 8 de Derxia sp., 4 de Herbarpirillum sp., 5 de Azospirillum sp., 1 de Gluconacetobacter sp. y 1 de Burkholderia sp. Por su alto potencial fueron seleccionados y criopreservados los aislamientos C27, C26, C25 y C45, las cuales presentaron los mejores valores de eficiencia in vitro, superando valores de producción de las cepas de referencia utilizadas (A. chroococcum (AC-01 y A. brasilense (SP7.

  20. Interaction of Azospirillum brasilense and Glomus intrarradix in Sugar Cane Roots.

    Science.gov (United States)

    Bellone, Carlos H; de Bellone Silvia, Carrizo

    2012-03-01

    Fifteen-day-old variety NA 56-79 sugar cane seedlings were inoculated with Azospirillum brasilense and Glomus intrarradix. This article aims at examining changes in sugar cane root seedlings inoculated with Glomus intrarradix and Azospirillum brasilense, the increase in microbial biomass and the acetylene reduction process as well. The internal root colonization was studied 20 days after inoculation using scanning and a transmission electron microscope. Both microorganisms entered the sugar cane root through the emergent lateral roots. The microorganisms were capable of coexisting both intra and intercellularly, producing changes in the cell wall, thus allowing colonization and interaction between the organisms. These changes increased the number of microorganisms inside the root as well as acetylene nitrogen reduction. Sugar cane plant biomass increased with joint-inoculation. The number of endophytic microorganisms and nitrogen fixing activity increased when they were colonized by Azospirillum and Glomus together.

  1. Directed mutagenesis affects recombination in Azospirillum brasilense nif genes

    Directory of Open Access Journals (Sweden)

    C.P. Nunes

    2000-12-01

    Full Text Available In order to improve the gene transfer/mutagenesis system for Azospirillum brasilense, gene-cartridge mutagenesis was used to replace the nifD gene with the Tn5 kanamycin resistance gene. The construct was transferred to A. brasilense by electrotransformation. Of the 12 colonies isolated using the suicide plasmid pSUP202 as vector, only four did not show vector integration into the chromosome. Nevertheless, all 12 colonies were deficient in acetylene reduction, indicating an Nif- phenotype. Four Nif- mutants were analyzed by Southern blot, using six different probes spanning the nif and Km r genes and the plasmid vector. Apparently, several recombination events occurred in the mutant genomes, probably caused mainly by gene disruption owing to the mutagenesis technique used: resistance gene-cartridge mutagenesis combined with electrotransformation.Com o objetivo de melhorar os sistemas de transferência gênica e mutagênese para Azospirillum brasilense, a técnica de mutagênese através do uso de um gene marcador ("gene-cartridge mutagenesis" foi utilizada para substituir a região genômica de A. brasilense correspondente ao gene nifD por um segmento de DNA do transposon Tn5 contendo o gene que confere resistência ao antibiótico canamicina. A construção foi transferida para a linhagem de A. brasilense por eletrotransformação. Doze colônias transformantes foram isoladas com o plasmídeo suicida pSUP202 servindo como vetor. Dessas, somente quatro não possuíam o vetor integrado no cromossomo da bactéria. Independentemente da integração ou não do vetor, as 12 colônias foram deficientes na redução do gás acetileno, evidenciando o fenótipo Nif -. Quatro mutantes Nif - foram analisados através da técnica de Southern blot, utilizando-se seis diferentes fragmentos contendo genes nif, de resistência à canamicina e do vetor como sondas. Os resultados sugerem a ocorrência de eventos recombinacionais variados no genoma dos mutantes. A

  2. Influence of soil saprophyte fungus Chaetomium cochliodes on associative system "Triticum aestivum – Azospirillum brasilense"

    Directory of Open Access Journals (Sweden)

    E. P. Kopylov

    2009-11-01

    Full Text Available In laboratory and vegetative experiments the ability of soil ascomycete C. cochliodes 3250 to promote the penetration of Azospirillum nitrogen-fixing bacteria into roots’ inner tissues was shown. At the same time the endophytic association: spring wheat – Azospirillum nitrogen-fixing bacteria – soil saprophyte ascomycete C. cochliodes 3250 is forming. It allows activating the nitrogen fixation in the spring wheat roots zone and biosynthetic processes in plants, in particular: to raise glutamine synthetase activity, chlorophylls content in leaves and plants’ productivity.

  3. [Chemical composition and immunochemical characteristics of the lipopolysaccharide of nitrogen-fixing rhizobacterium Azospirillum brasilense CD].

    Science.gov (United States)

    Konnova, O N; Burygin, G L; Fedonenko, Iu P; Matora, L Iu; Pankin, K E; Konnova, S A; Ignatov, V V

    2006-01-01

    The chemical composition of the lipopolysaccharide of the associative diazotrophic rhizobacterium Azospirillum brasilense Cd has been studied. Among the main components of the hydrophobic part of the lipopolysaccharide, we identified 3-hydroxytetradecanoic, hexadecenoic, 3-hydroxyhexadecanoic, hexadecanoic, octadecenoic, and nanodecanoic fatty acids; the carbohydrate part contained rhamnose, galactose, and mannose. Polyclonal antibodies against the preparation under study were raised in rabbits. Serological relations between A. brasilense Cd and other strains of Azospirillum spp. were studied using double radial immunodiffusion and enzyme-linked immunosorbent assay.

  4. cDNA-AFLP analysis of differential gene expression related to cell chemotactic and encystment of Azospirillum brasilense.

    Science.gov (United States)

    Li, Huamin; Cui, Yanhua; Wu, Lixian; Tu, Ran; Chen, Sanfeng

    2011-12-20

    Our previous study indicated org35 was involved in chemotaxis and interacted with nitrogen fixation transcriptional activator NifA via PAS domain. In order to reveal the role of org35 in nitrogen regulation, the downstream target genes of org35 were identified. We here report differentially expressed genes in org35 mutants comparing with wild type Sp7 by means of cDNA-AFLP. Four up-regulated transcript-derived fragments (TDFs) homologues of chemotaxis transduction proteins were found, including CheW, methyl-accepting chemotaxis protein and response regulator CheY-like receiver. Three distinct TDFs (AB46, AB58 and AB63) were similar to PHB de-polymerase C-terminus, cell shape-determining protein and flagellin domain protein. And 11 TDFs showed similarities with signal transduction proteins, including homologous protein of the nitrogen regulation protein NtrY and nitrate/nitrite response regulator protein NarL. These data suggested that the Azospirillum brasilense org35 was a multi-effecter and involved in chemotaxis, cyst development and regulation of nitrogen fixation.

  5. The chemotaxis-like Che1 pathway has an indirect role in adhesive cell properties of Azospirillum brasilense.

    Science.gov (United States)

    Siuti, Piro; Green, Calvin; Edwards, Amanda Nicole; Doktycz, Mitchel J; Alexandre, Gladys

    2011-10-01

    The Azospirillum brasilense chemotaxis-like Che1 signal transduction pathway was recently shown to modulate changes in adhesive cell surface properties that, in turn, affect cell-to-cell aggregation and flocculation behaviors rather than flagellar-mediated chemotaxis. Attachment to surfaces and root colonization may be functions related to flocculation. Here, the conditions under which A. brasilense wild-type Sp7 and che1 mutant strains attach to abiotic and biotic surfaces were examined using in vitro attachment and biofilm assays combined with atomic force microscopy and confocal microscopy. The nitrogen source available for growth is found to be a major modulator of surface attachment by A. brasilense and could be promoted in vitro by lectins, suggesting that it depends on interaction with surface-exposed residues within the extracellular matrix of cells. However, Che1-dependent signaling is shown to contribute indirectly to surface attachment, indicating that distinct mechanisms are likely underlying flocculation and attachment to surfaces in A. brasilense.

  6. Partial characterization of nif genes from the bacterium Azospirillum amazonense

    Directory of Open Access Journals (Sweden)

    D.P. Potrich

    2001-09-01

    Full Text Available Azospirillum amazonense revealed genomic organization patterns of the nitrogen fixation genes similar to those of the distantly related species A. brasilense. Our work suggests that A. brasilense nifHDK, nifENX, fixABC operons and nifA and glnB genes may be structurally homologous to the counterpart genes of A. amazonense. This is the first analysis revealing homology between A. brasilense nif genes and the A. amazonense genome. Sequence analysis of PCR amplification products revealed similarities between the amino acid sequences of the highly conserved nifD and glnB genes of A. amazonense and related genes of A. brasilense and other bacteria. However, the A. amazonense non-coding regions (the upstream activator sequence region and the region between the nifH and nifD genes differed from related regions of A. brasilense even in nitrogenase structural genes which are highly conserved among diazotrophic bacteria. The feasibility of the 16S ribosomal RNA gene-based PCR system for specific detection of A. amazonense was shown. Our results indicate that the PCR primers for 16S rDNA defined in this article are highly specific to A. amazonense and can distinguish this species from A. brasilense.

  7. Azospirillum brasilense siderophores with antifungal activity against Colletotrichum acutatum.

    Science.gov (United States)

    Tortora, María L; Díaz-Ricci, Juan C; Pedraza, Raúl O

    2011-04-01

    Anthracnose, caused by the fungus Colletotrichum acutatum is one of the most important diseases in strawberry crop. Due to environmental pollution and resistance produced by chemical fungicides, nowadays biological control is considered a good alternative for crop protection. Among biocontrol agents, there are plant growth-promoting bacteria, such as members of the genus Azospirillum. In this work, we demonstrate that under iron limiting conditions different strains of A. brasilense produce siderophores, exhibiting different yields and rates of production according to their origin. Chemical assays revealed that strains REC2 and REC3 secrete catechol type siderophores, including salicylic acid, detected by thin layer chromatography coupled with fluorescence spectroscopy and gas chromatography-mass spectrometry analysis. Siderophores produced by them showed in vitro antifungal activity against C. acutatum M11. Furthermore, this latter coincided with results obtained from phytopathological tests performed in planta, where a reduction of anthracnose symptoms on strawberry plants previously inoculated with A. brasilense was observed. These outcomes suggest that some strains of A. brasilense could act as biocontrol agent preventing anthracnose disease in strawberry.

  8. Partial characterization of nif genes from the bacterium Azospirillum amazonense.

    Science.gov (United States)

    Potrich, D P; Passaglia, L M; Schrank, I S

    2001-09-01

    Azospirillum amazonense revealed genomic organization patterns of the nitrogen fixation genes similar to those of the distantly related species A. brasilense. Our work suggests that A. brasilense nifHDK, nifENX, fixABC operons and nifA and glnB genes may be structurally homologous to the counterpart genes of A. amazonense. This is the first analysis revealing homology between A. brasilense nif genes and the A. amazonense genome. Sequence analysis of PCR amplification products revealed similarities between the amino acid sequences of the highly conserved nifD and glnB genes of A. amazonense and related genes of A. brasilense and other bacteria. However, the A. amazonense non-coding regions (the upstream activator sequence region and the region between the nifH and nifD genes) differed from related regions of A. brasilense even in nitrogenase structural genes which are highly conserved among diazotrophic bacteria. The feasibility of the 16S ribosomal RNA gene-based PCR system for specific detection of A. amazonense was shown. Our results indicate that the PCR primers for 16S rDNA defined in this article are highly specific to A. amazonense and can distinguish this species from A. brasilense.

  9. Optimization of biofloc production in Azospirillum brasilense (MTCC-125) and evaluation of its adherence with the roots of certain crops.

    Science.gov (United States)

    Joe, Melvin; Karthikeyan, M B; Sekar, C; Deiveekasundaram, M

    2010-10-01

    The phenomenon of flocculation in Azospirillum brasilense (MTCC-125) was studied under different combinations of carbon and nitrogen sources. Fructose and Potassium nitrate at a pH of 6.4 in the cultural medium favour a higher bio-floc production. The biofloc was studied for root adhesion and its survival efficiency in the rhizoplane and rhizosphere of certain crops such as sorghum and sunflower under dryland condition. It has been demonstrated that the flocculated cultures of Azospirillum were found to have maximum adhesion to the root surface and higher survival rate in the rhizoplane and rhizosphere under different moisture stressed conditions as compared to the log phase cells of Azospirillum.

  10. Comparative Study of Substrates and Inhibitors of Azospirillum lipoferum and Pyricularia oryzae Laccases

    OpenAIRE

    Faure, D.; Bouillant, M.; Bally, R.

    1995-01-01

    Azospirillum lipoferum and Pyricularia oryzae laccases were compared, using several substrates and inhibitors. Sixteen phenolic or nonphenolic compounds were found to be substrates of both fungal and bacterial laccases. In the presence of different phenol oxidase inhibitors, P. oryzae and A. lipoferum laccase activities had similar properties.

  11. Influence of Azospirillum spp. on the nitrogen supply of a gramineous host.

    NARCIS (Netherlands)

    Christiansen-Weniger, C.

    1991-01-01

    The main objectives of this study were to identify factors that control the behaviour of Azospirillum in the rhizosphere of a gramineous plant in order to be able to optimize the association between the bacteria and the host plants in terms of nitrogen supply to the host.Plant produced growth substa

  12. Repressor mutant forms of the Azospirillum brasilense NtrC protein.

    Science.gov (United States)

    Huergo, Luciano F; Assumpção, Marcelo C; Souza, Emanuel M; Steffens, M Berenice R; Yates, M Geoffrey; Chubatsu, Leda S; Pedrosa, Fábio O

    2004-10-01

    The Azospirillum brasilense mutant strains FP8 and FP9, after treatment with nitrosoguanidine, showed a null Nif phenotype and were unable to use nitrate as their sole nitrogen source. Sequencing of the ntrC genes revealed single nucleotide mutations in the NtrC nucleotide-binding site. The phenotypes of these strains are discussed in relation to their genotypes.

  13. Influence of tryptophan and indole-3-acetic acid on starch accumulation in the synthetic mutualistic Chlorella sorokiniana-Azospirillum brasilense system under heterotrophic conditions.

    Science.gov (United States)

    Palacios, Oskar A; Choix, Francisco J; Bashan, Yoav; de-Bashan, Luz E

    2016-06-01

    This study measured the relations between tryptophan production, the phytohormone indole-3-acetic acid (IAA) and the metabolism and accumulation of starch during synthetic mutualism between the microalgae Chlorella sorokiniana and the microalgae growth-promoting bacteria Azospirillum brasilense, created by co-immobilization in alginate beads. Experiments used two wild-type A. brasilense strains (Cd and Sp6) and an IAA-attenuated mutant (SpM7918) grown under nitrogen-replete and nitrogen-starved conditions tested under dark, heterotrophic and aerobic growth conditions. Under all incubating conditions, C. sorokiniana, but not A. brasilense, produced tryptophan. A significant correlation between IAA-production by A. brasilense and starch accumulation in C. sorokiniana was found, since the IAA-attenuated mutant was not producing increased starch levels. The highest ADP-glucose pyrophosphorylase (AGPase) activity, starch content and glucose uptake were found during the interaction of A. brasilense wild type strains with the microalgae. When the microalgae were grown alone, they produced only small amounts of starch. Supplementation with synthetic IAA to C. sorokiniana grown alone enhanced the above parameters, but only transiently. Activity of α-amylase decreased under nitrogen-replete conditions, but increased under nitrogen-starved conditions. In summary, this study demonstrated that, during synthetic mutualism, the exchange of tryptophan and IAA between the partners is a mechanism that governs several changes in starch metabolism of C. sorokiniana, yielding an increase in starch content.

  14. GlnB is specifically required for Azospirillum brasilense NifA activity in Escherichia coli.

    Science.gov (United States)

    Araújo, Luiza M; Monteiro, Rose A; Souza, Emanuel M; Steffens, M Berenice R; Rigo, Liu U; Pedrosa, Fábio O; Chubatsu, Leda S

    2004-01-01

    The Azospirillum brasilense transcription regulator NifA and the nitrogen-status signaling proteins GlnB, GlnZ and GlnK were expressed in Escherichia coli and analyzed for their ability to activate nif gene expression. When expressed separately, none of the proteins were able to activate nifH promoter expression in any tested conditions; in contrast, nifH expression was observed in cells grown in the absence of ammonium and oxygen and when expressing simultaneously NifA and GlnB proteins, but not when expressing NifA and GlnZ or GlnK. Our results show that the GlnB protein is required for transcription activation by Azospirillum brasilense NifA and it cannot be replaced by GlnZ or GlnK.

  15. Responses of Azospirillum brasilense to nitrogen deficiency and to wheat lectin: a diffuse reflectance infrared fourier transform (DRIFT) spectroscopic study.

    Science.gov (United States)

    Kamnev, Alexander A; Sadovnikova, Julia N; Tarantilis, Petros A; Polissiou, Moschos G; Antonyuk, Lyudmila P

    2008-11-01

    For the rhizobacterium Azospirillum brasilense, the optimal nutritional range of C:N ratios corresponds to the presence of malate (ca. 3 to 5 g l(-1) of its sodium salt) and ammonium (ca. 0.5 to 3 g l(-1) of NH4Cl) as preferred carbon and nitrogen sources, respectively. This microaerophilic aerotactic bacterium is known to have a narrow optimal oxygen concentration range of ca. 3 to 5 microM, which is 1.2% to 2% of oxygen solubility in air-saturated water under normal conditions. In this work, the effects of stress conditions (bound-nitrogen deficiency related to a high C:N ratio in the medium; excess of oxygen) on aerobically grown A. brasilense Sp245, a native wheat-associated endophyte, were investigated in the absence and presence of wheat germ agglutinin (WGA, plant stress protein and a molecular host-plant signal for the bacterium) using FTIR spectroscopy of whole cells in the diffuse reflectance mode (DRIFT). The nutritional stress resulted in the appearance of prominent spectroscopic signs of poly-3-hydroxybutyrate (PHB) accumulation in the bacterial cells; in addition, splitting of the amide I band related to bacterial cellular proteins indicated some stress-induced alterations in their secondary structure components. Similar structural changes were observed in the presence of nanomolar WGA both in stressed A. brasilense cells and under normal nutritional conditions. Comparative analysis of the data obtained and the relevant literature data indicated that the stress conditions applied (which resulted in the accumulation of PHB involved in stress tolerance) and/or the presence of nanomolar concentrations of WGA induced synthesis of bacterial cell-surface (glyco)proteins rich in beta-structures, that could be represented by hemagglutinin and/or porin.

  16. Metabolic Adaptations of Azospirillum brasilense to Oxygen Stress by Cell-to-Cell Clumping and Flocculation

    OpenAIRE

    Bible, Amber N.; Khalsa-Moyers, Gurusahai K.; Mukherjee, Tanmoy; Green, Calvin S.; Mishra, Priyanka; Purcell, Alicia; Aksenova, Anastasia; Gregory B Hurst; Alexandre, Gladys

    2015-01-01

    The ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacterium Azospirillum brasilense navigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motile A. brasilense cells implement an alternative response to aerotaxis and form transient clum...

  17. Identification of a phosphoenolpyruvate:fructose 1-phosphotransferase system in Azospirillum brasilense.

    OpenAIRE

    Gupta, K. D.; S. Ghosh

    1984-01-01

    An inducible phosphoenolpyruvate:fructose phosphotransferase system has been detected in Azospirillum brasilense, which requires a minimum of two components of the crude extracts for activity: (i) a soluble fraction (enzyme I) and (ii) a membrane fraction (enzyme II). The uninduced cells neither show any uptake of fructose nor express activity of either of these two enzyme fractions. C-1 of fructose is the site of phosphorylation. This phosphotransferase system does not accept glucose as a su...

  18. Fourier transform infrared spectroscopic study of intact cells of the nitrogen-fixing bacterium Azospirillum brasilense

    Science.gov (United States)

    Kamnev, A. A.; Ristić, M.; Antonyuk, L. P.; Chernyshev, A. V.; Ignatov, V. V.

    1997-06-01

    The data of Fourier transform infrared (FTIR) spectroscopic measurements performed on intact cells of the soil nitrogen-fixing bacterium Azospirillum brasilense grown in a standard medium and under the conditions of an increased metal uptake are compared and discussed. The structural FTIR information obtained is considered together with atomic absorption spectrometry (AAS) data on the content of metal cations in the bacterial cells. Some methodological aspects concerning preparation of bacterial cell samples for FTIR measurements are also discussed.

  19. Relative efficiency of Azotobacter and Azospirillum on yield and P utilization by wheat (Triticum Aestivum) with various N levels

    International Nuclear Information System (INIS)

    Efficiency of 32P labelled single superphosphate along with N levels (0, 60, 80 and 120 kg/ha) and biofertilizers (Azotobacter and Azospirillum) was studied on wheat in Typic ustifluvent (saline phase) soil. Average grain and straw yield, total P uptake, per cent P derived by crop from applied phosphorus and its utilization in grain and straw increased either with Azospirillum or Azotobacter inoculation. However, the magnitude of increase in these attributes was of higher extent in presence of Azotobacter as compared to Azospirillum. The yield, uptake and utilization of P increased with increasing levels of N. Per cent Pdff was higher with all levels of N over control, whereas, it was at par with their successive levels. Interaction effect between levels of nitrogen and biofertilizers were also positive and significant at all levels of N with respect to yield and uptake of P, while per cent Pdff and its utilization by wheat was more pronounced at 60 and 80 kg N ha-1 in the presence of Azotobacter. Azospirillum was more effective at 60 kg of N than the other levels. Generally, Azotobacter performed better than the Azospirillum with respect to all parameters. (author)

  20. Structural and functional peculiarities of the lipopolysaccharide of Azospirillum brasilense SR55, isolated from the roots of Triticum durum.

    Science.gov (United States)

    Boyko, Alevtina S; Konnova, Svetlana A; Fedonenko, Yulia P; Zdorovenko, Evelina L; Smol'kina, Olga N; Kachala, Vadim V; Ignatov, Vladimir V

    2011-10-20

    Azospirillum brasilense SR55, isolated from the rhizosphere of Triticum durum, was classified as serogroup II on the basis of serological tests. Such serogroup affiliation is uncharacteristic of wheat-associated Azospirillum species. The lipid A of A. brasilense SR55 lipopolysaccharide contained 3-hydroxytetradecanoic, 3-hydroxyhexadecanoic, hexadecanoic and octadecenoic fatty acids. The structure of the lipopolysaccharide's O polysaccharide was established, with the branched octasaccharide repeating unit being represented by l-rhamnose, l-3-O-Me-rhamnose, d-galactose and d-glucuronic acid. The SR55 lipopolysaccharide induced deformations of wheat root hairs. The lipopolysaccharide was not involved in bacterial cell aggregation, but its use to pretreat wheat roots was conducive to cell adsorption. This study shows that Azospirillum bacteria can utilise their own lipopolysaccharide as a carbon source, which may give them an advantage in competitive natural environments.

  1. Cellulose decomposition and associated nitrogen fixation by mixed cultures of Cellulomonas gelida and Azospirillum species or Bacillus macerans

    Energy Technology Data Exchange (ETDEWEB)

    Halsall, D.M.; Gibson, A.H.

    1985-10-01

    Mixed cultures of Cellulomonas gelida plus Azospirillum lipoferum or Azospirillum brasilense and C. gelida plus Bacillus macerans were shown to degrade cellulose and straw and to utilize the energy-yielding products to fix atmospheric nitrogen. This cooperative process was followed over 30 days in sand-based cultures in which the breakdown of 20% of the cellulose and 28 to 30% of the straw resulted in the fixation of 12 to 14.6 mg of N per g of cellulose and 17 to 19 mg of N per g of straw consumed. Cellulomonas species have certain advantages over aerobic cellulose-degrading fungi in being able to degrade cellulose at oxygen concentrations as low as 1% O/sub 2/ (vol/vol) which would allow a close association between cellulose-degrading and microaerobic diazotrophic microorganisms. Cultures inoculated with initially different proportions of A. brasilense and C. gelida all reached a stable ratio of approximately 1 Azospirillum/3 Cellulomonas cells.

  2. Improvement of endophytic Azospirillum colonization by co-inoculation with Cellulomonas Uda ATCC 491

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Mehdipour Moghaddam

    2014-04-01

    Full Text Available Introduction: Most of the plant growth promoting rhizobacteria (PGPR such as Azopirillum if accompanied with strong cellulase producing bacteria such as Cellulomonas, their colonization may be increased and their host plants growth improved. Materials and methods: Six endophytic Azospirilla which isolated from three rice and three wheat cultivars and also one strain from commercial biofertilizer (Green Biotech Co., identified by biochemical tests and 16S rDNA analysis and were studied on the basis of cellulase, pectinase and auxin production and also their chemotaxis toward rice and wheat cultivars exudates was investigated. Two cellulase positive (A5 and A6 and two negative (A2 and A3 strains were selected and their interaction with C. uda ATCC 491 on auxin production and colonization on roots were compared. Results: This study showed that none of the strains had pectinase activity, but the strain isolated from rice had more Carboxy methyl cellulase (CMCase activity. Selected isolates and C. uda ATCC 491 showed chemotaxis toward roots exudates. In most of the isolates, rate of auxin production increased by coculture with C. uda ATCC 491. Also, it was determined that C. uda ATCC 491 promoted the colonization of Azospirillum without or with cellulase activity on rice and wheat roots, respectively. Discussion and conclusion: Co-inoculation Azospirillum with C. uda ATCC 491 improves plant root system due to stimulation or additive effect of auxin production and cellulase activity, followed by more uptakes of water and minerals by roots. Also, it raises the number of colonization niches for useful bacteria such as Azospirillum and finally quantitative and qualitative plant parameters.

  3. Characterization of the flagellar biosynthesis regulatory geneflbD in Azospirillum brasilense

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A flagellar gene cluster fragment includingflbD of Azospirillum brasilense was cloned and sequenced, The flbD mutant strain was found to be nonmotile-losing both polar and lateral flagella (Fla-Laf-), Motility and flagella were regained by complementation with plasmid-borne multicopy flbD, but altered with larger swarming circle and fewer lateral flagella on the semisolid plate, This result indicated that FIbD plays an important role in the regulation of both polar and lateral flagellar biosynthesis in A.brasilense.

  4. Increased acidification in the rhizosphere of cactus seedlings induced by Azospirillum brasilense

    Science.gov (United States)

    Carrillo, Angel; Li, Ching; Bashan, Yoav

    2002-08-01

    Acidification of the rhizosphere of cactus seedlings (giant cardon, Pachycereus pringlei) after inoculation with the plant growth-promoting bacterium Azospirillum brasilense Cd, in the presence or absence of ammonium and nitrate, was studied to understand how to increase growth of cardon seedlings in poor desert soils. While ammonium enhanced rhizosphere and liquid culture acidification, inoculation with the bacteria enhanced it further. On the other hand, nitrate increased pH of the rhizosphere, but combined with the bacterial inoculation, increase in pH was significantly smaller. Bacterial inoculation with ammonium enhanced plant growth.

  5. Regulation of fructose uptake and catabolism by succinate in Azospirillum brasilense.

    OpenAIRE

    Mukherjee, A; S. Ghosh

    1987-01-01

    Fructose uptake and catabolism in Azospirillum brasilense is dependent on three fructose-inducible enzymes (fru-enzymes): (i) enzyme I and (ii) enzyme II of the phosphoenolpyruvate:fructose phosphotransferase system and (iii) 1-phosphofructokinase. In minimal medium containing 3.7 mM succinate and 22 mM fructose as sources of carbon, growth of A. brasilense was diauxic, succinate being utilized in the first phase of growth and fructose in the second phase with a lag period between the two gro...

  6. Structure of the polysaccharides from the lipopolysaccharide of Azospirillum brasilense Jm125A2.

    Science.gov (United States)

    Sigida, Elena N; Fedonenko, Yuliya P; Shashkov, Alexander S; Zdorovenko, Evelina L; Konnova, Svetlana A; Ignatov, Vladimir V; Knirel, Yuriy A

    2015-10-30

    Two polysaccharides were obtained by mild acid degradation of the lipopolysaccharide of associative nitrogen-fixing bacteria Azospirillum brasilense Jm125A2 isolated from the rhizosphere of a pearl millet. The following structures of the polysaccharides were established by sugar and methylation analyses, Smith degradation, and (1)H and (13)C NMR spectroscopy: [Formula: see text] Structure 1 has been reported earlier for a polysaccharide from A. brasilense S17 (Fedonenko YP, Konnova ON, Zdorovenko EL, Konnova SA, Zatonsky GV, Shaskov AS, Ignatov VV, Knirel YA. Carbohydr Res 2008;343:810-6), whereas to our knowledge structure 2 has not been hitherto found in bacterial polysaccharides.

  7. Penggunaan Azospirillum pada Tanah Masam dengan Aluminium Tinggi Terhadap Produksi dan Serapan Nitrogen Rumput Setaria splendida dan Chloris gayana

    Directory of Open Access Journals (Sweden)

    P.D.M.H. Karti

    2005-04-01

    Full Text Available High content of Al on the soil maybe harmful (toxic for plant. Red and yellow podzolic soil was marginal land that characterized by high Al content. Azospirillum is free living N fixing bacteria that can be associated with grass. This research was conducted to find the best yield of grass planted on the soil inoculated with Azospirillum. The research consisted of some steps; 1 soil sampling 2 laboratory research: bacterial isolation, isolate selection, standardized of population, content of IAA 3 pod experiment. Pod experiment in the glass house was designed in completely randomized design, that consisted of six treatments. The variables observed were dry mass production of shoot and root, nitrogen content of shoot and root, and nitrogen absorption. Four best isolates chosen were; SM Setaria, OBIS/BD, PO2 and PM2. Azospirillum isolates enhanced shoot and root production, nitrogen content and N total absorption of tolerance one (S. splendida. The susceptible (C. gayana, Azospirillum significantly enhanced shoot and root nitrogen content, but did not affect the growth, production and N total absorption. Root growth that was inhibited by Al toxicity, decreased the symbiotic capability of nitrogen fixing bacteria. PM2 isolate showed the best effect on production and quality of S. splendida as well as on C. gayana. This isolate will be used for future research. PM2 produces 6.4 ppm Indole Acetic Acid that promoted root growth.

  8. Insights into the 1.59-Mbp largest plasmid of Azospirillum brasilense CBG497.

    Science.gov (United States)

    Acosta-Cruz, Erika; Wisniewski-Dyé, Florence; Rouy, Zoé; Barbe, Valérie; Valdés, María; Mavingui, Patrick

    2012-09-01

    The plant growth-promoting proteobacterium Azospirillum brasilense enhances growth of many economically important crops, such as wheat, maize, and rice. The sequencing and annotation of the 1.59-Mbp replicon of A. brasilense CBG497, a strain isolated from a maize rhizosphere grown on an alkaline soil in the northeast of Mexico, revealed a GC content of 68.7 % and the presence of 1,430 potential protein-encoding genes, 1,147 of them classified into clusters of orthologous groups categories, and 16 tRNA genes representing 11 tRNA species. The presence of sixty-two genes representatives of the minimal gene set and chromid core genes suggests its importance in bacterial survival. The phaAB → G operon, reported as involved in the bacterial adaptation to alkaline pH in the presence of K(+), was also found on this replicon and detected in several Azospirillum strains. Phylogenetic analysis suggests that it was laterally acquired. We were not able to show its inference on the adaptation to basic pH, giving a hint about the presence of an alternative system for adaptation to alkaline pH.

  9. Oxidative and antioxidative responses in the wheat-Azospirillum brasilense interaction.

    Science.gov (United States)

    Méndez-Gómez, Manuel; Castro-Mercado, Elda; Alexandre, Gladys; García-Pineda, Ernesto

    2016-03-01

    Azospirillum is a plant growth-promoting rhizobacteria (PGPR) able to enhance the growth of wheat. The aim of this study was to test the effect of Azospirillum brasilense cell wall components on superoxide (O2·(-)) production in wheat roots and the effect of oxidative stress on A. brasilense viability. We found that inoculation with A. brasilense reduced O2·(-) levels by approx. 30 % in wheat roots. Inoculation of wheat with papain-treated A. brasilense, a Cys protease, notably increased O2·(-) production in all root tissues, as was observed by the nitro blue tetrazolium (NBT) reduction. However, a 24-h treatment with rhizobacteria lipopolysaccharides (50 and 100 μg/mL) alone did not affect the pattern of O2·(-) production. Analysis of the effect of plant cell wall components on A. brasilense oxidative enzyme activity showed no changes in catalase activity but a decrease in superoxide dismutase activity in response to polygalacturonic acid treatment. Furthermore, A. brasilense growth was only affected by high concentrations of H2O2 or paraquat, but not by sodium nitroprusside. Our results suggest that rhizobacterial cell wall components play an important role in controlling plant cell responses and developing tolerance of A. brasilense to oxidative stress produced by the plant.

  10. Trehalose accumulation in Azospirillum brasilense improves drought tolerance and biomass in maize plants.

    Science.gov (United States)

    Rodríguez-Salazar, Julieta; Suárez, Ramón; Caballero-Mellado, Jesús; Iturriaga, Gabriel

    2009-07-01

    Bacteria of the genus Azospirillum increase the grain yield of several grass crops. In this work the effect of inoculating maize plants with genetically engineered Azospirillum brasilense for trehalose biosynthesis was determined. Transformed bacteria with a plasmid harboring a trehalose biosynthesis gene-fusion from Saccharomyces cerevisiae were able to grow up to 0.5 M NaCl and to accumulate trehalose, whereas wild-type A. brasilense did not tolerate osmotic stress or accumulate significant levels of the disaccharide. Moreover, 85% of maize plants inoculated with transformed A. brasilense survived drought stress, in contrast with only 55% of plants inoculated with the wild-type strain. A 73% increase in biomass of maize plants inoculated with transformed A. brasilense compared with inoculation with the wild-type strain was found. In addition, there was a significant increase of leaf and root length in maize plants inoculated with transformed A. brasilense. Therefore, inoculation of maize plants with A. brasilense containing higher levels of trehalose confers drought tolerance and a significant increase in leaf and root biomass. This work opens the possibility that A. brasilense modified with a chimeric trehalose biosynthetic gene from yeast could increase the biomass, grain yield and stress tolerance in other relevant crops.

  11. Oxidative and antioxidative responses in the wheat-Azospirillum brasilense interaction.

    Science.gov (United States)

    Méndez-Gómez, Manuel; Castro-Mercado, Elda; Alexandre, Gladys; García-Pineda, Ernesto

    2016-03-01

    Azospirillum is a plant growth-promoting rhizobacteria (PGPR) able to enhance the growth of wheat. The aim of this study was to test the effect of Azospirillum brasilense cell wall components on superoxide (O2·(-)) production in wheat roots and the effect of oxidative stress on A. brasilense viability. We found that inoculation with A. brasilense reduced O2·(-) levels by approx. 30 % in wheat roots. Inoculation of wheat with papain-treated A. brasilense, a Cys protease, notably increased O2·(-) production in all root tissues, as was observed by the nitro blue tetrazolium (NBT) reduction. However, a 24-h treatment with rhizobacteria lipopolysaccharides (50 and 100 μg/mL) alone did not affect the pattern of O2·(-) production. Analysis of the effect of plant cell wall components on A. brasilense oxidative enzyme activity showed no changes in catalase activity but a decrease in superoxide dismutase activity in response to polygalacturonic acid treatment. Furthermore, A. brasilense growth was only affected by high concentrations of H2O2 or paraquat, but not by sodium nitroprusside. Our results suggest that rhizobacterial cell wall components play an important role in controlling plant cell responses and developing tolerance of A. brasilense to oxidative stress produced by the plant. PMID:25952083

  12. Key physiological properties contributing to rhizosphere adaptation and plant growth promotion abilities of Azospirillum brasilense.

    Science.gov (United States)

    Fibach-Paldi, Sharon; Burdman, Saul; Okon, Yaacov

    2012-01-01

    Azospirillum brasilense is a plant growth promoting rhizobacterium (PGPR) that is being increasingly used in agriculture in a commercial scale. Recent research has elucidated key properties of A. brasilense that contribute to its ability to adapt to the rhizosphere habitat and to promote plant growth. They include synthesis of the auxin indole-3-acetic acid, nitric oxide, carotenoids, and a range of cell surface components as well as the ability to undergo phenotypic variation. Storage and utilization of polybetahydroxyalkanoate polymers are important for the shelf life of the bacteria in production of inoculants, products containing bacterial cells in a suitable carrier for agricultural use. Azospirillum brasilense is able to fix nitrogen, but despite some controversy, as judging from most systems evaluated so far, contribution of fixed nitrogen by this bacterium does not seem to play a major role in plant growth promotion. In this review, we focus on recent advances in the understanding of physiological properties of A. brasilense that are important for rhizosphere performance and successful interactions with plant roots.

  13. The ipdC, hisC1 and hisC2 genes involved in indole-3-acetic production used as alternative phylogenetic markers in Azospirillum brasilense.

    Science.gov (United States)

    Jijón-Moreno, Saúl; Marcos-Jiménez, Cynthia; Pedraza, Raúl O; Ramírez-Mata, Alberto; de Salamone, I García; Fernández-Scavino, Ana; Vásquez-Hernández, Claudia A; Soto-Urzúa, Lucia; Baca, Beatriz E

    2015-06-01

    Plant growth-promoting bacteria of the genus Azospirillum are present in the rhizosphere and as endophytes of many crops. In this research we studied 40 Azospirillum strains isolated from different plants and geographic regions. They were first characterized by 16S rDNA restriction analysis, and their phylogenetic position was established by sequencing the genes 16S rDNA, ipdC, hisC1, and hisC2. The latter three genes are involved in the indole-3-pyruvic acid (IPyA) biosynthesis pathway of indole-3-acetic acid (IAA). Furthermore, the suitability of the 16S-23S rDNA intergenic spacer sequence (IGS) for the differentiation of closely related Azospirillum taxa and development of PCR protocols allows for specific detection of strains. The IGS-RFLP analysis enabled intraspecies differentiation, particularly of Azospirillum brasilense and Azospirillum lipoferum strains. Results demonstrated that the ipdC, hisC1, and hisC2 genes are highly conserved in all the assessed A. brasilense isolates, suggesting that these genes can be used as an alternative phylogenetic marker. In addition, IAA production determined by HPLC ranged from 0.17 to 98.2 μg mg(-1) protein. Southern hybridization with the A. brasilense ipdC gene probe did not show, a hybridization signal with A. lipoferum, Azospirillum amazonense, Azospirillum halopreferans and Azospirillum irakense genomic DNA. This suggests that these species produce IAA by other pathways. Because IAA is mainly synthesized via the IPyA pathway in A. brasilense strains, a species that is used worldwide in agriculture, the identification of ipdC, hisC1, and hisC2 genes by PCR may be suitable for selecting exploitable strains.

  14. Residual effect of nitrogen fertilization and Azospirillum brasilense inoculation in the maize culture
    Efeito residual da adubação nitrogenada e inoculação de Azospirillum brasilense na cultura do milho

    OpenAIRE

    Jackson Huzar Novakowiski; Aníbal de Moraes; Margarete Kimie Falbo; Itacir Eloi Sandini; Jaqueline Huzar Novakowiski; Nicole Colombari Cheng

    2011-01-01

    The diazotrophic bacteria Azospirillum brasilense is an organism able to fix nitrogen of atmosphere and produce plant hormones. Nevertheless, there is lack of information with regard to use in field conditions, especially in production systems that have presence of animals in a determined year period. The objective of paper was to evaluate the association of the nitrogen residual effect of fertilization in pasture winter and the inoculation with A. brasilense in the maize culture. Were carrie...

  15. Toxicidade de herbicidas utilizados na cultura da cana-de-açúcar à bactéria diazotrófica Azospirillum brasilense Toxicity of herbicides applied on sugarcane to the diazotrophic bacterium Azospirillum brasilense

    OpenAIRE

    S.O. Procópio; M.F. Fernandes; D.A Teles; J.G Sena Filho; A. Cargnelutti Filho; L. Vargas; S.A.C Sant'Anna

    2011-01-01

    Objetivou-se neste trabalho identificar herbicidas utilizados na cultura da cana-de-açúcar que não alteram o crescimento ou a capacidade de fixação biológica de nitrogênio (FBN) da bactéria diazotrófica Azospirillum brasi lense. Dezoito herbicidas - paraquat, ametryn, amicarbazone, diuron, metribuzin, [hexazinone + diuron], [hexazinone + clomazone], clomazone, isoxaflutole, sulfentrazone, oxyfluorfen, imazapic, imazapyr, [trifloxysulfuron-sodium + ametryn], S-metolachlor, glyphosate, MSMA e 2...

  16. Corn Yield and Foliar Diagnosis Affected by Nitrogen Fertilization and Inoculation with Azospirillum brasilense

    Directory of Open Access Journals (Sweden)

    Fernando Shintate Galindo

    2016-01-01

    Full Text Available ABSTRACT The biological nitrogen fixation (BNF process in grasses is caused by diazotrophic bacteria, particularly Azospirillum brasilense. However, studies are lacking on BNF efficiency to define how much mineral nitrogen (N can be applied to achieve more sustainable high yields. Furthermore, there should be an analysis of whether urea with the urease enzyme inhibitor NBPT is less harmful, benefiting BNF in grasses. The objective of this study was to evaluate the effect of N sources and N rates associated with inoculation with Azospirillum brasilense regarding foliar diagnosis and leaf chlorophyll index (LCI, agronomic efficiency (AE, and corn grain yield in the Cerrado (Brazilian tropical savanna region. The experiment was conducted in a no-tillage system in a Latossolo Vermelho Distroférrico (Oxisol. A randomized block experimental design was used with four replications in a 2 × 5 × 2 factorial arrangement as follows: two N sources - urea and Super N, urea with urease enzyme inhibitor NBPT [N - (n-butyl thiophosphoric triamide]; five N rates (0, 50, 100, 150, and 200 kg ha-1 applied in topdressing; and two seed inoculation treatments, one with and one without A. brasilense. N rate positively influenced the LCI and concentrations of N, S, and Mn in leaves, and may increase the concentrations of P, Cu, and Fe; however, higher N rates can reduce AE. The N sources had similar effects, and therefore urea is recommended for N fertilization. Inoculation with A. brasilense decreased leaf concentration of Fe and increased LCI, leaf concentration of P, AE, and corn grain yield; the use of this diazotrophic bacterium is therefore viable even when high rates of N are applied.

  17. Monitoring of cobalt(II) uptake and transformation in cells of the plant-associated soil bacterium Azospirillum brasilense using emission Mössbauer spectroscopy.

    Science.gov (United States)

    Kamnev, Alexander A; Antonyuk, Lyudmila P; Kulikov, Leonid A; Perfiliev, Yury D

    2004-08-01

    Interaction of cobalt(II) at micromolar concentrations with live cells of the plant-growth-promoting rhizobacterium Azospirillum brasilense (strain Sp245) and further transformations of the metal cation were monitored using 57Co emission Mössbauer spectroscopy (EMS). Cell suspensions of the bacterial culture (2.4 x 10(8) cells ml(-1)) were doped with radioactive 57CoCl2 (1 mCi; final concentration 2 x 10(-6) M 57Co2+), kept under physiological conditions for various periods of time (from 2 min up to 1 hour) and then rapidly frozen in liquid nitrogen. Analysis of emission Mössbauer spectra of the frozen aqueous suspensions of the bacterial cell samples shows that the primary absorption of cobalt(II) at micromolar concentrations by the bacterial cells is rapid and virtually complete, giving at least two major forms of cobalt(II) species bound to the cells. Within an hour, the metal is involved in further metabolic transformations reflected by changes occurring in the spectra. The Mössbauer parameters calculated from the EMS data by statistical treatment were different for suspensions of live and dead (thermally killed) bacterial cells that had been in contact with 57Co2+ for 1 h, as well as for the cell-free culture medium containing the same concentration of 57Co2+. Chemical after-effects of the nuclear transition (57Co --> 5 7Fe), which provide additional information on the chemical environment of metal ions, are also considered. The data presented demonstrate that EMS is a valuable tool for monitoring the chemical state of cobalt species in biological matter providing information at the atomic level in the course of its uptake and/or metabolic transformations.

  18. Response of Sunflower Yield and Phytohormonal Changes to Azotobacter,Azospirillum,Pseudomonas and Animal Manure in a Chemical Free Agroecosystem

    OpenAIRE

    Maziyar, Mehran; M. Reza, Ardakani; Hamid, Madani; Mohammad , Zahedi; Mohsen, Amirabadi; Saeed, Mafakheri

    2011-01-01

    There are new trends in agriculture to move toward the low input systems with the lower application of chemical fertilizers. To reach this goal, different methods, such as the application of biofertilizers, may be used. So this experiment was conducted in 2010 at a research farm in Arak, Iran, in factorial in the form of a randomized complete block design with three replications and four factors: animal manure (M), Pseudomonas putida (P), Azotobacter chroococcum (A)and Azospirillum lipoferum ...

  19. [INFLUENCE OF AZOSPIRILLUM BRASILENSE 10/1 ON ASSOCIATIVE NITROGEN FIXATION AND INTRAVARIETAL POLYMORPHISM OF SPRING TRITICALE].

    Science.gov (United States)

    Patika, V P; Nadkernichna, O V; Shahovnina, O O

    2015-01-01

    It is shown, that the perspective Ukrainian sorts of spring triticale characterizes by considerable polymorphism by associative N2-fixing ability in root zone of plants. Application of active strain Azospirillum brasilense 10/1 promotes the decline of variability of this sign within the limits of sort, increase potential nitrogen activity is on the average in 3,2-4,7 times and also distributing normalizations in the selections of the inoculated plants.

  20. Protein Quantity and Quality of Safflower Seed Improved by NP Fertilizer and Rhizobacteria (Azospirillum and Azotobacter spp.)

    Science.gov (United States)

    Nosheen, Asia; Bano, Asghari; Yasmin, Humaira; Keyani, Rumana; Habib, Rabia; Shah, Syed T. A.; Naz, Rabia

    2016-01-01

    HIGHLIGHTS Rhizobacteria (Azotobacter spp.) have improved the quality and quantity of safflower seed protein.Protein quality was confirmed by SDS-PAGE and new bands were found in response to different combinations of rhizobacteria and lower doses of fertilizers.The PGPR application has reduced the use of fertilizers upto 50%. Protein is an essential part of the human diet. The aim of this present study was to improve the protein quality of safflower seed by the application of plant growth promoting rhizobacteria (PGPR) in combination with conventional nitrogen and phosphate (NP) fertilizers. The seeds of two safflower cultivars Thori and Saif-32, were inoculated with Azospirillum and Azotobacter and grown under field conditions. Protein content and quality was assessed by crude protein, amino acid analysis, and SDS-PAGE. Seed crude protein and amino acids (methionine, phenylalanine, and glutamic acid) showed significant improvements (55–1250%) by Azotobacter supplemented with a quarter dose of fertilizers (BTQ) at P ≤ 0.05. Additional protein bands were induced in Thori and Saif-32 by BTQ and BTH (Azotobacter supplemented with a half dose of fertilizer) respectively. The Azospirillum in combination with half dose of fertilizer (SPH) and BTQ enhanced both indole acetic acid (IAA) (90%) and gibberellic acid (GA) (23–27%) content in safflower leaf. Taken together, these data suggest that Azospirillum and Azotobacter along with significantly reduced (up to 75%) use of NP fertilizers could improve the quality and quantity of safflower seed protein. PMID:26941744

  1. Protein quantity and quality of safflower seed improved by NP fertilizer and rhizobacteria (Azospirillum and Azotobacter spp.

    Directory of Open Access Journals (Sweden)

    Asia eNosheen

    2016-02-01

    Full Text Available Protein is an essential part of human diet. The aim of present study was to improve the protein quality of safflower seed by the application of plant growth promoting rhizobacteria (PGPR in combination with conventional nitrogen and phosphate (NP fertilizers. The seeds of two safflower cultivar Thori and Saif-32, were inoculated with Azospirillum and Azotobacter and grown under field conditions. Protein content and quality was assessed by crude protein, amino acid analysis and SDS-PAGE. Seed crude protein and amino acids (metheonine, phenylanine and glutamic acid showed significant improvement (55%–1250% by Azotobacter supplemented with quarter dose of fertilizers (BTQ at P≤0.05. Additional protein bands were induced in Thori and Saif-32 by BTQ and BTH (Azotobacter supplemented with half dose of fertilizers respectively. The Azospirillum in combination with half dose of fertilizers (SPH and BTQ enhanced the indole acetic acid (90% and gibberellic acid (23%–27% contents in safflower leaf. Taken together, these data suggest that Azospirillum and Azotobacter along with significantly reduced (up to 75% use of NP fertilizers improved the quality and quantity of safflower seed protein.

  2. Computer simulation and experimental study of the polysaccharide-polysaccharide interaction in the bacteria Azospirillum brasilense Sp245

    Science.gov (United States)

    Arefeva, Oksana A.; Kuznetsov, Pavel E.; Tolmachev, Sergey A.; Kupadze, Machammad S.; Khlebtsov, Boris N.; Rogacheva, Svetlana M.

    2003-09-01

    We have studied the conformational properties and molecular dynamics of polysaccharides by using molecular modeling methods. Theoretical and experimental results of polysaccharide-polysaccharide interactions are described.

  3. Nitric oxide metabolism and indole acetic acid biosynthesis cross-talk in Azospirillum brasilense SM.

    Science.gov (United States)

    Koul, Vatsala; Tripathi, Chandrakant; Adholeya, Alok; Kochar, Mandira

    2015-04-01

    Production of nitric oxide (NO) and the presence of NO metabolism genes, nitrous oxide reductase (nosZ), nitrous oxide reductase regulator (nosR) and nitric oxide reductase (norB) were identified in the plant-associated bacterium (PAB) Azospirillum brasilense SM. NO presence was confirmed in all overexpressing strains, while improvement in the plant growth response of these strains was mediated by increased NO and indole-3-acetic acid (IAA) levels in the strains. Electron microscopy showed random distribution to biofilm, with surface colonization of pleiomorphic Azospirilla. Quantitative IAA estimation highlighted a crucial role of nosR and norBC in regulating IAA biosynthesis. The NO quencher and donor reduced/blocked IAA biosynthesis by all strains, indicating their common regulatory role in IAA biosynthesis. Tryptophan (Trp) and l-Arginine (Arg) showed higher expression of NO genes tested, while in the case of ipdC, only Trp and IAA increased expression, while Arg had no significant effect. The highest nosR expression in SMnosR in the presence of IAA and Trp, along with its 2-fold IAA level, confirmed the relationship of nosR overexpression with Trp in increasing IAA. These results indicate a strong correlation between IAA and NO in A. brasilense SM and suggest the existence of cross-talk or shared signaling mechanisms in these two growth regulators.

  4. Crecimiento de Azospirillum brasilense en presencia de disacáridos: sacarosa y lactosa

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    Yudyt Díaz-Saez

    2013-01-01

    Full Text Available La obtención de biopolímeros a partir de fermentaciones bacterianas requiere de la selección adecuada de las condiciones del proceso. Se evaluó el crecimiento de la cepa Azospirillum brasilense 8-INICA en medio líquido suplementado con disacáridos. Las mediciones se realizaron a las 23 h de incubación con la determinación de la densidad óptica, la concentración de azúcares reductores y concentración de carbohidratos totales, así como la determinación del pH del sobrenadante. Se confirmó el máximo desarrollo de la biomasa para 33 oC y 7,2 g.L-1 de sal con sacarosa, y 40 oC y 3,5 g.L-1 de sal con lactosa. Se estableció que las condiciones más favorables para la producción de exopolisacáridos se encuentran a temperaturas y concentraciones elevadas de sal para un medio con lactosa; y bajas temperaturas a concentraciones elevadas de sal en presencia de sacarosa. Se constató la marcada influencia de la temperatura en el crecimiento, y la acción positiva de la concentración salina en los mecanismos de supervivencia del micro- organismo.

  5. Physiological and biochemical characterization of Azospirillum brasilense strains commonly used as plant growth-promoting rhizobacteria.

    Science.gov (United States)

    Di Salvo, Luciana P; Silva, Esdras; Teixeira, Kátia R S; Cote, Rosalba Esquivel; Pereyra, M Alejandra; García de Salamone, Inés E

    2014-12-01

    Azospirillum is a plant growth-promoting rhizobacteria (PGPR) genus vastly studied and utilized as agriculture inoculants. Isolation of new strains under different environmental conditions allows the access to the genetic diversity and improves the success of inoculation procedures. Historically, the isolation of this genus has been performed by the use of some traditional culture media. In this work we characterized the physiology and biochemistry of five different A. brasilense strains, commonly used as cereal inoculants. The aim of this work is to contribute to pose into revision some concepts concerning the most used protocols to isolate and characterize this bacterium. We characterized their growth in different traditional and non-traditional culture media, evaluated some PGPR mechanisms and characterized their profiles of fatty acid methyl esters and carbon-source utilization. This work shows, for the first time, differences in both profiles, and ACC deaminase activity of A. brasilense strains. Also, we show unexpected results obtained in some of the evaluated culture media. Results obtained here and an exhaustive knowledge revision revealed that it is not appropriate to conclude about bacterial species without analyzing several strains. Also, it is necessary to continue developing studies and laboratory techniques to improve the isolation and characterization protocols.

  6. Transcriptome analysis of the rhizosphere bacterium Azospirillum brasilense reveals an extensive auxin response.

    Science.gov (United States)

    Van Puyvelde, Sandra; Cloots, Lore; Engelen, Kristof; Das, Frederik; Marchal, Kathleen; Vanderleyden, Jos; Spaepen, Stijn

    2011-05-01

    The rhizosphere bacterium Azospirillum brasilense produces the auxin indole-3-acetic acid (IAA) through the indole-3-pyruvate pathway. As we previously demonstrated that transcription of the indole-3-pyruvate decarboxylase (ipdC) gene is positively regulated by IAA, produced by A. brasilense itself or added exogenously, we performed a microarray analysis to study the overall effects of IAA on the transcriptome of A. brasilense. The transcriptomes of A. brasilense wild-type and the ipdC knockout mutant, both cultured in the absence and presence of exogenously added IAA, were compared.Interfering with the IAA biosynthesis/homeostasis in A. brasilense through inactivation of the ipdC gene or IAA addition results in much broader transcriptional changes than anticipated. Based on the multitude of changes observed by comparing the different transcriptomes, we can conclude that IAA is a signaling molecule in A. brasilense. It appears that the bacterium, when exposed to IAA, adapts itself to the plant rhizosphere, by changing its arsenal of transport proteins and cell surface proteins. A striking example of adaptation to IAA exposure, as happens in the rhizosphere, is the upregulation of a type VI secretion system (T6SS) in the presence of IAA. The T6SS is described as specifically involved in bacterium-eukaryotic host interactions. Additionally, many transcription factors show an altered regulation as well, indicating that the regulatory machinery of the bacterium is changing.

  7. Metabolic Adaptations of Azospirillum brasilense to Oxygen Stress by Cell-to-Cell Clumping and Flocculation

    Science.gov (United States)

    Bible, Amber N.; Khalsa-Moyers, Gurusahai K.; Mukherjee, Tanmoy; Green, Calvin S.; Mishra, Priyanka; Purcell, Alicia; Aksenova, Anastasia; Hurst, Gregory B.

    2015-01-01

    The ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacterium Azospirillum brasilense navigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motile A. brasilense cells implement an alternative response to aerotaxis and form transient clumps by cell-to-cell interactions. Clumping was suggested to represent a behavior protecting motile cells from transiently elevated levels of aeration. Using the proteomics of wild-type and mutant strains affected in the extent of their clumping abilities, we show that cell-to-cell clumping represents a metabolic scavenging strategy that likely prepares the cells for further metabolic stresses. Analysis of mutants affected in carbon or nitrogen metabolism confirmed this assumption. The metabolic changes experienced as clumping progresses prime cells for flocculation, a morphological and metabolic shift of cells triggered under elevated-aeration conditions and nitrogen limitation. The analysis of various mutants during clumping and flocculation characterized an ordered set of changes in cell envelope properties accompanying the metabolic changes. These data also identify clumping and early flocculation to be behaviors compatible with the expression of nitrogen fixation genes, despite the elevated-aeration conditions. Cell-to-cell clumping may thus license diazotrophy to microaerophilic A. brasilense cells under elevated oxygen conditions and prime them for long-term survival via flocculation if metabolic stress persists. PMID:26407887

  8. Purification and binding analysis of the nitrogen fixation regulatory NifA protein from Azospirillum brasilense

    Directory of Open Access Journals (Sweden)

    L.M.P. Passaglia

    1998-11-01

    Full Text Available NifA protein activates transcription of nitrogen fixation operons by the alternative sigma54 holoenzyme form of RNA polymerase. This protein binds to a well-defined upstream activator sequence (UAS located at the -200/-100 position of nif promoters with the consensus motif TGT-N10-ACA. NifA of Azospirillum brasilense was purified in the form of a glutathione-S-transferase (GST-NifA fusion protein and proteolytic release of GST yielded inactive and partially soluble NifA. However, the purified NifA was able to induce the production of specific anti-A. brasilense NifA-antiserum that recognized NifA from A. brasilense but not from K. pneumoniae. Both GST-NifA and NifA expressed from the E. coli tac promoter are able to activate transcription from the nifHDK promoter but only in an A. brasilense background. In order to investigate the mechanism that regulates NifA binding capacity we have used E. coli total protein extracts expressing A. brasilense nifA in mobility shift assays. DNA fragments carrying the two overlapping, wild-type or mutated UAS motifs present in the nifH promoter region revealed a retarded band of related size. These data show that the binding activity present in the C-terminal domain of A. brasilense NifA protein is still functional even in the presence of oxygen.

  9. Purification and characterisation of Azospirillum brasilense N-truncated NtrX protein.

    Science.gov (United States)

    Assumpção, Marcelo Constantino; de Souza, Emanuel Maltempi; Yates, M Geoffrey; de Oliveira Pedrosa, Fábio; Benelli, Elaine Machado

    2007-06-01

    The NtrX protein has been identified as a transcriptional activator of genes involved in the metabolic control of alternative nitrogen sources, acting as a member of a two-component regulatory system. The in silico analysis of the NtrX amino acid sequence shows that this protein contains an N-terminal receiver domain, a central AAA+ superfamily domain and a C-terminal DNA binding domain. To over-express and purify this protein, the ntrX gene of Azospirillum brasilense lacking the first eight codons was cloned into the vector pET29a+. The NtrX protein was over-expressed as an S.Tag fusion protein induced by l-arabinose in the Escherichia coli strain BL21AI and purified by ion exchange and affinity chromatography. The ATPase activity of NtrX was measured by coupling the ATP conversion to ADP with NADH oxidation. The ATPase activity of NtrX was stimulated in the presence of A. brasilense sigma(54)/NtrC-dependent promoter of the glnBA gene. Phosphorylation by carbamyl-phosphate also stimulated ATPase, in a manner similar to the NtrC protein. Together our results suggest that NtrX is active in the phosphorylated form and that there may be a cross-talk between the NtrYX and NtrBC regulatory systems in A. brasilense.

  10. Growth and yield of corn hybrids in response to association with Azospirillum brasilense and nitrogen fertilization

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    Deniele Marini

    2015-02-01

    Full Text Available There is a growing interest in optimizing the positive effects of the association between Azospirillum bacteria and corn crop in order to reduce the use of nitrogen fertilizers. This study aimed to evaluate the inoculation efficiency of an A. brasilense-based commercial product in association with different rates of nitrogen fertilization in two corn genotypes. The experiment was arranged in a 2 x 2 x 5 factorial randomized block design, with four replications. The treatments consisted of two corn hybrids (30F53 and CD386; with and without inoculation with a commercial product based on A. brasilense and five nitrogen rates (0, 40, 80, 120 and 160 kg ha-1. The variables plant height, basal stem diameter, leaf area, shoot dry matter, leaf nitrogen content, length and diameter of the cob, weight of 100 grains and grain yield were evaluated. Inoculation with A. brasilense provided increases of 11 and 12% in leaf area and shoot dry matter, respectively. There were differences in the response of the corn hybrids for most variables and the increase in nitrogen supply provided increments in the growth and yield of corn.

  11. Nitrogen translocation in wheat inoculated with Azospirillum and fertilized with nitrogen

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    RODRIGUES OSMAR

    2000-01-01

    Full Text Available The productivity and the translocation of assimilates and nitrogen (N were compared after inoculation of wheat (Triticum aestivum L., cv. BR-23 seeds with two strains of Azospirillum brasilense (strains 245 and JA 04 under field conditions. The inoculation of wheat seeds was done with a peat inoculant at sowing time. Plant material for evaluations were collected at anthesis and maturity. No differences in grain yield and in the translocation of assimilates resulting from inoculation were detected. Differences were observed in relation to N rates (0, 15, and 60 kg ha-1. N content in the grain increased significantly in the bacteria-inoculated treatments in which N was not added. This increase in N content in the grain with inoculation was probably due to higher N uptake after anthesis without any significant contribution on the grain yield. Such increment was of 8.4 kg ha-1 of N representing 66% more N than in no inoculated treatment. Regardless of the inoculation and the rate of N applied, it was observed that about 70% of the N accumulated at anthesis was translocated from vegetative parts to the grain.

  12. Co-inoculation of Azospirillum brasilense and Herbaspirillum seropedicae in maize

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    Janaína Dartora

    2016-06-01

    Full Text Available ABSTRACT Bacteria from the genera Azospirillum and Herbaspirillum have been associated with increments in maize yield. The aim of this study was to evaluate the maize yield and nutritional content in response to inoculation with A. brasilense and H. seropediceae in association with nitrogen (N fertilization. The experimental design was randomized blocks in a 4 x 5 factorial scheme, with four replicates. The treatments consisted of seed inoculation (control without N and inoculation, A. brasilense strain - AbV5, H. seropediceae strain - SMR1 and co-inoculation AbV5 + SMR1 and N doses (0, 40, 80, 120 and 160 kg ha-1. The following variables were evaluated: ear insertion height, ear length, ear diameter, number of rows per ear, number of grains per row, ear weight, yield and NPK contents in leaves and grains. There was no interaction between the factors studied. Co-inoculation with the strains promoted increments of 12% in leaf P content, compared with control, and N fertilization promoted increase in yield and leaf P content up to the maximum dose studied.

  13. In vitro uridylylation of the Azospirillum brasilense N-signal transducing GlnZ protein.

    Science.gov (United States)

    Araujo, Mariana S; Baura, Valter A; Souza, Emanuel M; Benelli, Elaine M; Rigo, Liu U; Steffens, M Berenice R; Pedrosa, Fabio O; Chubatsu, Leda S

    2004-01-01

    Azospirillum brasilense is a diazotroph which associates with important agricultural crops. The nitrogen fixation process in this organism is highly regulated by ammonium and oxygen, and involves several proteins including the two PII-like proteins, GlnB and GlnZ. Although these proteins are structurally very similar, they play different roles in the control of nitrogen fixation. In this work, we describe the expression, purification, and uridylylation of the GlnZ protein of A. brasilense strain FP2. The amplified glnZ gene was sub-cloned and expressed as a His-tagged fusion protein. After purification, we obtained 30-40 mg of purified GlnZ per liter of culture. This protein was purified to 99% purity and assayed for in vitro uridylylation using a partially purified Escherichia coli GlnD as a source of uridylylyl-transferase activity. Analyses of the uridylylation reactions in non-denaturing and denaturing polyacrylamide gel electrophoresis showed that up to 74% of GlnZ monomers were modified after 30 min reaction. This covalent modification is strictly dependent on ATP and 2-ketoglutarate, while glutamine acts as an inhibitor and promotes deuridylylation.

  14. Components of corn crop yield under inoculation with Azospirillum brasilense using integrated crop-livestock system

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    Marcos da Silva Brum

    2016-09-01

    Full Text Available The objective of this study was to evaluate the agronomic characteristics of corn seed inoculated with Azospirillum brasilense, grown on black oat and ryegrass straw, and managed under different grazing strategies and doses of nitrogen. The experiment was conducted in Santa Maria, Rio Grande do Sul State, Brazil, during two agricultural seasons (2012/2013 and 2013/2014 in a randomized, complete block design with three replications. In the winter period, black oat and ryegrass straw were managed at different grazing heights by sheep (0.30, 0.20, 0.10 m, conventional grazing, and no grazing with three doses of nitrogen (0, 50, and 100 kg ha-1, with or without inoculation by A. brasilense. We used the hybrid Pioneer (P1630H® in 2012 and the hybrid Agroeste (AS 1551® in 2013. The height of corn plants was greater when they were grown on black oat and ryegrass straw, and the absence of grazing favored productivity. Under drought conditions, the application of nitrogen to the pasture favored corn development, increasing plant height, ear height, and stem diameter. Inoculation with A. brasilense had a positive effect on the characteristics of yield and productivity of corn, independent of growing season and hybrid used.

  15. Cloning, sequencing, and characterization of the Azospirillum brasilense fhuE gene.

    Science.gov (United States)

    Cui, Yanhua; Tu, Ran; Guan, Yue; Ma, Luyan; Chen, Sanfeng

    2006-03-01

    The fhuE gene of Escherichia coli encodes the FhuE protein, which is a receptor protein in the coprogen-mediated siderophore iron-transport system. A fhuE gene homologue from Azospirillum brasilense, a nitrogen-fixing soil bacterium that lives in association with the roots of cereal grasses, was cloned, sequenced, and characterized. The A. brasilense fhuE encodes a protein of 802 amino acids with a predicted molecular weight of approximately 87 kDa. The deduced amino-acid sequence showed a high level of homology to the sequences of all the known fhuE gene products. The fhuE mutant was sensitive to iron starvation and defective in coprogen-mediated iron uptake. The mutant failed to express one membrane protein of approximately 78 kDa that was induced by iron starvation in the wild type. Complementation studies showed that the A. brasilense fhuE gene, when present on a low-copy number plasmid, could restore the functions of the mutant. Mutation in fhuE gene did not affect nitrogen fixation.

  16. Evaluation of reference genes for gene expression analysis using quantitative RT-PCR in Azospirillum brasilense.

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    Mary McMillan

    Full Text Available Azospirillum brasilense is a nitrogen fixing bacterium that has been shown to have various beneficial effects on plant growth and yield. Under normal conditions A. brasilense exists in a motile flagellated form, which, under starvation or stress conditions, can undergo differentiation into an encapsulated, cyst-like form. Quantitative RT-PCR can be used to analyse changes in gene expression during this differentiation process. The accuracy of quantification of mRNA levels by qRT-PCR relies on the normalisation of data against stably expressed reference genes. No suitable set of reference genes has yet been described for A. brasilense. Here we evaluated the expression of ten candidate reference genes (16S rRNA, gapB, glyA, gyrA, proC, pykA, recA, recF, rpoD, and tpiA in wild-type and mutant A. brasilense strains under different culture conditions, including conditions that induce differentiation. Analysis with the software programs BestKeeper, NormFinder and GeNorm indicated that gyrA, glyA and recA are the most stably expressed reference genes in A. brasilense. The results also suggested that the use of two reference genes (gyrA and glyA is sufficient for effective normalisation of qRT-PCR data.

  17. Evaluation of reference genes for gene expression analysis using quantitative RT-PCR in Azospirillum brasilense.

    Science.gov (United States)

    McMillan, Mary; Pereg, Lily

    2014-01-01

    Azospirillum brasilense is a nitrogen fixing bacterium that has been shown to have various beneficial effects on plant growth and yield. Under normal conditions A. brasilense exists in a motile flagellated form, which, under starvation or stress conditions, can undergo differentiation into an encapsulated, cyst-like form. Quantitative RT-PCR can be used to analyse changes in gene expression during this differentiation process. The accuracy of quantification of mRNA levels by qRT-PCR relies on the normalisation of data against stably expressed reference genes. No suitable set of reference genes has yet been described for A. brasilense. Here we evaluated the expression of ten candidate reference genes (16S rRNA, gapB, glyA, gyrA, proC, pykA, recA, recF, rpoD, and tpiA) in wild-type and mutant A. brasilense strains under different culture conditions, including conditions that induce differentiation. Analysis with the software programs BestKeeper, NormFinder and GeNorm indicated that gyrA, glyA and recA are the most stably expressed reference genes in A. brasilense. The results also suggested that the use of two reference genes (gyrA and glyA) is sufficient for effective normalisation of qRT-PCR data.

  18. Metabolic adaptations of Azospirillum brasilense to oxygen stress by cell-to-cell clumping and flocculation.

    Science.gov (United States)

    Bible, Amber N; Khalsa-Moyers, Gurusahai K; Mukherjee, Tanmoy; Green, Calvin S; Mishra, Priyanka; Purcell, Alicia; Aksenova, Anastasia; Hurst, Gregory B; Alexandre, Gladys

    2015-12-01

    The ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacterium Azospirillum brasilense navigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motile A. brasilense cells implement an alternative response to aerotaxis and form transient clumps by cell-to-cell interactions. Clumping was suggested to represent a behavior protecting motile cells from transiently elevated levels of aeration. Using the proteomics of wild-type and mutant strains affected in the extent of their clumping abilities, we show that cell-to-cell clumping represents a metabolic scavenging strategy that likely prepares the cells for further metabolic stresses. Analysis of mutants affected in carbon or nitrogen metabolism confirmed this assumption. The metabolic changes experienced as clumping progresses prime cells for flocculation, a morphological and metabolic shift of cells triggered under elevated-aeration conditions and nitrogen limitation. The analysis of various mutants during clumping and flocculation characterized an ordered set of changes in cell envelope properties accompanying the metabolic changes. These data also identify clumping and early flocculation to be behaviors compatible with the expression of nitrogen fixation genes, despite the elevated-aeration conditions. Cell-to-cell clumping may thus license diazotrophy to microaerophilic A. brasilense cells under elevated oxygen conditions and prime them for long-term survival via flocculation if metabolic stress persists.

  19. (Methyl)ammonium transport in the nitrogen-fixing bacterium Azospirillum brasilense.

    Science.gov (United States)

    Van Dommelen, A; Keijers, V; Vanderleyden, J; de Zamaroczy, M

    1998-05-01

    An ammonium transporter of Azospirillum brasilense was characterized. In contrast to most previously reported putative prokaryotic NH4+ transporter genes, A. brasilense amtB is not part of an operon with glnB or glnZ which, in A. brasilense, encode nitrogen regulatory proteins PII and PZ, respectively. Sequence analysis predicts the presence of 12 transmembrane domains in the deduced AmtB protein and classifies AmtB as an integral membrane protein. Nitrogen regulates the transcription of the amtB gene in A. brasilense by the Ntr system. amtB is the first gene identified in A. brasilense whose expression is regulated by NtrC. The observation that ammonium uptake is still possible in mutants lacking the AmtB protein suggests the presence of a second NH4+ transport mechanism. Growth of amtB mutants at low ammonium concentrations is reduced compared to that of the wild type. This suggests that AmtB has a role in scavenging ammonium at low concentrations.

  20. Potential roles for the glnB and ntrYX genes in Azospirillum brasilense.

    Science.gov (United States)

    Vitorino, J C; Steffens, M B; Machado, H B; Yates, M G; Souza, E M; Pedrosa, F O

    2001-07-24

    Three Azospirillum brasilense mutants constitutive for nitrogen fixation (Nif(C)) in the presence of NH4(+) and deficient in nitrate-dependent growth were used as tools to define the roles of the glnB and ntrYX genes in this organism. Mutant HM14 was complemented for nitrate-dependent growth and NH4(+) regulation of nitrogenase by plasmid pL46 which contains the ntrYX genes of A. brasilense. Mutant HM26 was restored for NH4(+) regulation and nitrate-dependent growth by plasmid pJC1, carrying the A. brasilense glnB gene expressed from a constitutive promoter. Mutant HM053, on the other hand, was not complemented for NH4(+) regulation of nitrogenase and nitrate-dependent growth by both plasmids pJCI and pL46. The levels and control of glutamine synthetase activity of all mutants were not affected by both plasmids pL46 (ntrYX) and pJC1 (glnB). These results support the characterization of strains HM14 as an ntrYX mutant and strain HM26 as a glnB mutant and the involvement of ntrYX and glnB in the regulation of the general nitrogen metabolism in A. brasilense.

  1. Purification and binding analysis of the nitrogen fixation regulatory NifA protein from Azospirillum brasilense.

    Science.gov (United States)

    Passaglia, L M; Van Soom, C; Schrank, A; Schrank, I S

    1998-11-01

    NifA protein activates transcription of nitrogen fixation operons by the alternative sigma 54 holoenzyme form of RNA polymerase. This protein binds to a well-defined upstream activator sequence (UAS) located at the -200/-100 position of nif promoters with the consensus motif TGT-N10-ACA. NifA of Azospirillum brasilense was purified in the form of a glutathione-S-transferase (GST)-NifA fusion protein and proteolytic release of GST yielded inactive and partially soluble NifA. However, the purified NifA was able to induce the production of specific anti-A. brasilense NifA-antiserum that recognized NifA from A. brasilense but not from K. pneumoniae. Both GST-NifA and NifA expressed from the E. coli tac promoter are able to activate transcription from the nifHDK promoter but only in an A. brasilense background. In order to investigate the mechanism that regulates NifA binding capacity we have used E. coli total protein extracts expressing A. brasilense nifA in mobility shift assays. DNA fragments carrying the two overlapping, wild-type or mutated UAS motifs present in the nifH promoter region revealed a retarded band of related size. These data show that the binding activity present in the C-terminal domain of A. brasilense NifA protein is still functional even in the presence of oxygen.

  2. Chemical synthesis of the tetrasaccharide repeating unit of the O-polysaccharide isolated from Azospirillum brasilense SR80.

    Science.gov (United States)

    Sarkar, Vikramjit; Mukhopadhyay, Balaram

    2015-04-10

    A linear strategy has been developed for the synthesis of the tetrasaccharide repeating unit of the O-polysaccharide from Azospirillum brasilense SR80. Stepwise glycosylation of the rationally protected thioglycoside donors activated by NIS in the presence of La(OTf)3 furnished the target tetrasaccharide. The glycosylation reactions resulted in the formation of the desired linkage with absolute stereoselectivity and afforded the required derivatives in good to excellent yields. The phthalimido group has been used as the precursor of the desired acetamido group to meet the requirement of 1,2-trans glycosidic linkage.

  3. Nitrogenase switch-off by ammonium ions in Azospirillum brasilense requires the GlnB nitrogen signal-transducing protein.

    Science.gov (United States)

    Klassen, Giseli; Souza, Emanuel M; Yates, M Geoffrey; Rigo, Liu Un; Costa, Roberta M; Inaba, Juliana; Pedrosa, Fábio O

    2005-09-01

    Nitrogenase activity in several diazotrophs is switched off by ammonium and reactivated after consumption. The signaling pathway to this system in Azospirillum brasilense is not understood. We show that ammonium-dependent switch-off through ADP-ribosylation of Fe protein was partial in a glnB mutant of A. brasilense but absent in a glnB glnZ double mutant. Triggering of inactivation by anaerobic conditions was not affected in either mutant. The results suggest that glnB is necessary for full ammonium-dependent nitrogenase switch-off in A. brasilense.

  4. Mutational analysis of GlnB residues critical for NifA activation in Azospirillum brasilense.

    Science.gov (United States)

    Inaba, Juliana; Thornton, Jeremy; Huergo, Luciano Fernandes; Monteiro, Rose Adele; Klassen, Giseli; Pedrosa, Fábio de Oliveira; Merrick, Mike; de Souza, Emanuel Maltempi

    2015-02-01

    PII proteins are signal transduction that sense cellular nitrogen status and relay this signals to other targets. Azospirillum brasilense is a nitrogen fixing bacterium, which associates with grasses and cereals promoting beneficial effects on plant growth and crop yields. A. brasilense contains two PII encoding genes, named glnB and glnZ. In this paper, glnB was mutagenised in order to identify amino acid residues involved in GlnB signaling. Two variants were obtained by random mutagenesis, GlnBL13P and GlnBV100A and a site directed mutant, GlnBY51F, was obtained. Their ability to complement nitrogenase activity of glnB mutant strains of A. brasilense were determined. The variant proteins were also overexpressed in Escherichia coli, purified and characterized biochemically. None of the GlnB variant forms was able to restore nitrogenase activity in glnB mutant strains of A. brasilense LFH3 and 7628. The purified GlnBY51F and GlnBL13P proteins could not be uridylylated by GlnD, whereas GlnBV100A was uridylylated but at only 20% of the rate for wild type GlnB. Biochemical and computational analyses suggest that residue Leu13, located in the α helix 1 of GlnB, is important to maintain GlnB trimeric structure and function. The substitution V100A led to a lower affinity for ATP binding. Together the results suggest that NifA activation requires uridylylated GlnB bound to ATP.

  5. Azospirillum Inoculation Alters Nitrate Reductase Activity and Nitrogen Uptake in Wheat Plant under Water Deficit Conditions

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    N. Aliasgharzad N. Aliasgharzad

    2014-01-01

    Full Text Available Water deficit stress usually diminishes nitrogen uptake by plants. There are evidences that some nitrogen fixing bacteria can alleviate this stress by supplying nitrogen and improving its metabolism in plants. Four Azospirillum strains, A. lipoferum AC45-II, A. brasilense AC46-I, A. irakense AC49-VII and A. irakense AC51-VI were tested for nitrate reductase activity (NRA. In a pot culture experiment using a sandy loam soil, wheat plants (Triticum aestivum L. cv. Sardari were inoculated with these bacterial strains and three ranges of soil water potential (W1: -10 to -20, W2: -40 to -50 and W3: -65 to -75 kPa were applied to the pots. All strains were positive in NRA test and the highest (7.63mg NO2-N.L-1.48h-1 was recorded for AC49-VII and the least (0.23mg NO2-N.L-1.48h-1 was belong to AC51-VI. Leaf and root NRA, root and shoot nitrogen concentrations, and dry weights of root and shoot decreased by increasing water deficit stress. All four bacterial strains caused a significant enhancement in root NRA and in each water deficit level, the higher root NRA was recorded in AC46-I and AC49-VII inoculated plants. The highest leaf NRA was achieved by AC49-VII. The mean increment of root NRA by bacterial strains was 171% compared to the non-bacterial plants. Moreover, at the highest level of water deficit stress, the highest dry weight and nitrogen concentration in root and shoot were obtained by AC46-I and AC49-VII treatments.

  6. Effect of Azospirillum brasilense and Burkholderia unamae Bacteria on Maize Photosynthetic Activity Evaluated Using the Photoacoustic Technique

    Science.gov (United States)

    Gordillo-Delgado, F.; Marín, E.; Calderón, A.

    2016-09-01

    In this work, the photosynthetic process of maize plants ( Zea mays), which were grown using seeds inoculated with plant growth promoting bacteria Azospirillum brasilense and Burkholderia unamae, was monitored. Photothermal and photobaric signals obtained by a time-resolved photoacoustic measurement configuration were used for measuring the oxygen evolution rate in situ. A frequency-resolved configuration of the method was utilized to determine the oxygen diffusion coefficient and the thermal diffusivity of the maize leaves. The latter parameters, which can be used as indicators of the photosynthetic activity of maize, are found to vary according to the plant-microbe interaction. Treatment with plant growth promoting bacteria induced a decrease in the oxygen diffusion coefficient of about 20 %.

  7. [Effect of the fungicide captan on Azospirillum brasilense Cd in pure culture and associated with Setaria italica].

    Science.gov (United States)

    Di Ciocco, C A; Rodríguez Cáceres, E

    1997-01-01

    The effect of fungicide captan on growth and nitrogenase activity of Azospirillum brasilense Cd was studied in pure cultures and in association with foxtail millet (Setaria italica) cultivar Carapé under laboratory conditions. The 8 h growth in rotary shaker of A. brasilense was inhibited with 1 mg/l pure captan; however, after 4 days the differences diminished compared with the control without captan. Nitrogenase activity was affected with 10 mg/l but the differences were negligible after 48 h of growth. Root dry weight of inoculated plants was diminished by the treatment of foxtail millet cv. Carapé with captan. Inoculation with A. brasilense Cd increased shoot dry weight, but differences were significant only with respect to the control but not in relation to captan treatments.

  8. EFFECT OF MOISTURE LEVELS ON THE GROWTH, NODULATION AND NITROGEN FIXATION IN Dalbergia sissoo BY Azospirillum brasilense AND Acaulospora laevis

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    Gaurav Bhushan

    2014-08-01

    Full Text Available In present study, influence of single and combined inoculation of Azospirillum brasilense and Acaulospora laevis on the growth, nodulation and N2 fixation in Dalbergia sissoo was tested at various moisture levels under pot culture conditions. Combined inoculation of A.brasilense and A.laevis was found best in raising maximum growth, nodulation, nitrogen fixation and percentage of AM colonization in roots. These characters were considerably influenced with the increasing moisture stress from -0.3MPa to -1.5MPa. Furthermore, the values of all the above mentioned parameters show decrement with the increasing of moisture stress. Plants with dual inoculation performed better than single inoculated plants. Observation of the present study counted a protective role played by AM in providing resistance to D.sissoo against injurious effects of moisture stress.

  9. Optimal fed batch experiment design for estimation of monod kinetics of Azospirillum brasilense: from theory to practice.

    Science.gov (United States)

    Cappuyns, Astrid M; Bernaerts, Kristel; Smets, Ilse Y; Ona, Ositadinma; Prinsen, Els; Vanderleyden, Jos; Van Impe, Jan F

    2007-01-01

    In this paper the problem of reliable and accurate parameter estimation for unstructured models is considered. It is illustrated how a theoretically optimal design can be successfully translated into a practically feasible, robust, and informative experiment. The well-known parameter estimation problem of Monod kinetic parameters is used as a vehicle to illustrate our approach. As known for a long time, noisy batch measurements do not allow for unique and accurate estimation of the kinetic parameters of the Monod model. Techniques of optimal experiment design are, therefore, exploited to design informative experiments and to improve the parameter estimation accuracy. During the design process, practical feasibility has to be kept in mind. The designed experiments are easy to implement in practice and do not require additional monitoring equipment. Both design and experimental validation of informative fed batch experiments are illustrated with a case study, namely, the growth of the nitrogen-fixing bacteria Azospirillum brasilense.

  10. Respuesta de tres cultivares de maíz a la inoculación con Azospirillum brasilense bajo cuatro diferentes dosis de nitrógeno

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    Andrés González Huerta

    2011-01-01

    Full Text Available En el municipio de Huamuxtitlán, estado de Guerrero, México, se evaluó la respuesta de los materiales de maíz VS-535, H-507 y criollo veracruzano en las dosis de 0, 30, 60 y 90 kg de nitrógeno ha-1, con y sin Azospirillum brasilense. En el sintético VS- 535 se registró el mayor rendimiento de grano (5.23 t ha-1. En las dosis de 0, 30, 60 y 90 kg de N ha-1 se registraron 4.38, 4.36, 4.81 y 4.93 t ha-1, respectivamente. La diferencia entre aplicar o no Azospirillum brasilense (promedio sobre los factores A, B y repeticiones fue de 1.47 t ha-1 y de dos días en el ciclo biológico del cultivo.

  11. Respuesta de tres cultivares de maíz a la inoculación con Azospirillum brasilense bajo cuatro diferentes dosis de nitrógeno

    OpenAIRE

    Andrés González Huerta; Delfina de Jesús Pérez López; Omar Franco Mora; Artemio Balbuena Melgarejo; Francisco Gutiérrez Rodríguez; Heladio Romero Salas

    2011-01-01

    En el municipio de Huamuxtitlán, estado de Guerrero, México, se evaluó la respuesta de los materiales de maíz VS-535, H-507 y criollo veracruzano en las dosis de 0, 30, 60 y 90 kg de nitrógeno ha-1, con y sin Azospirillum brasilense. En el sintético VS- 535 se registró el mayor rendimiento de grano (5.23 t ha-1). En las dosis de 0, 30, 60 y 90 kg de N ha-1 se registraron 4.38, 4.36, 4.81 y 4.93 t ha-1, respectivamente. La diferencia entre aplicar o no Azospirillum brasilense (promedio sobre l...

  12. Nodulation of legumes, nitrogenase activity of roots and occurrence of nitrogen-fixing Azospirillum spp. In representative soils of central Amazonia

    Energy Technology Data Exchange (ETDEWEB)

    Sylvester-Bradley, R.; De Oliverira, L.A.; De Podesta Filho, J.A.; St. John, T.V.

    1980-12-01

    Leguminosae do not predominate in the Brazilian Amazon rain forest, although they are among the five best represented families. Plant roots from various soils were examined for the presence of nodules, acetylene-reducing activity and N/sub 2/-fixing Azospirillum spp. Abundant nodulation was found in black earth (''terra preta dos indios'') and in one case on sandy soil under campinarana vegetation along a tributary of the upper Rio Negro. In sandy latosol some nodules occurred in secondary forest and fewer in primary forest. Legumes in disturbed clayey or sandy latosol showed more frequent nodulation. Primary forest on alluvial (''varzea'') soil, and in Bahia coastal rain forest on sandy latosol and Erythrina glauca used for shading cacao plantations were abundantly nodulated. Acetylene reduction assays showed no, or very little, nitrogenase activity of roots from primary or secondary forest on clayey latosol near Manaus. Nodulated roots from secondary forest on sandy latosol showed acetylene-reducing activity. High rates of acetylene reduction were observed in nodulated roots of primary forest on alluvial ''varzea'' soil. Root samples showed ethylene absorption in controls without acetylene which might interfere with the results of acetylene reduction tests. The incidence of Azospirillum was also higher in black earth than the other soils examined, and in soils with higher pH. The hypothesis that Azospirillum is associated with Trema micantha roots was refuted. Roots and soils collected under cultivated grasses showed a higher incidence of Azospirillum when fertilized with phosphorus and lime. Results indicate that nitrogen fixation did occur in association with roots in some soils, but not with roots of primary or secondary forest on clayey latosol in the vicinity of Manaus, which is the most common soil in Central Amazonia. The possible reasons for this are discussed.

  13. Evaluación de la zeolita como soporte sólido para la formulación del biofertilizante Azospirillum

    OpenAIRE

    Dayamí Borges-Rodríguez; Ana Nelis San Juan-Rodríguez; Angela O. Díaz-LLanes; Eulalia Gómez-Santiesteban; Raúl Hernández-Sanchez

    2012-01-01

    Se realizó una caracterización física de la zeolita proveniente de los yacimientos de San Juan de la Yeras, con el objetivo de evaluar sus posibilidades para ser usada como soporte sólido en la formulación del biofertilizante Azospirillum. Se evaluaron fracciones de tres tamaños de partícula, de las que la fracción Zoac (

  14. Physiological, structural and molecular traits activated in strawberry plants after inoculation with the plant growth-promoting bacterium Azospirillum brasilense REC3.

    Science.gov (United States)

    Guerrero-Molina, M F; Lovaisa, N C; Salazar, S M; Martínez-Zamora, M G; Díaz-Ricci, J C; Pedraza, R O

    2015-05-01

    The plant growth-promoting strain REC3 of Azospirillum brasilense, isolated from strawberry roots, prompts growth promotion and systemic protection against anthracnose disease in this crop. Hence, we hypothesised that A. brasilense REC3 can induce different physiological, structural and molecular responses in strawberry plants. Therefore, the aim of this work was to study these traits activated in Azospirillum-colonised strawberry plants, which have not been assessed until now. Healthy, in vitro micropropagated plants were root-inoculated with REC3 under hydroponic conditions; root and leaf tissues were sampled at different times, and oxidative burst, phenolic compound content, malondialdehyde (MDA) concentration, callose deposition, cell wall fortification and gene expression were evaluated. Azospirillum inoculation enhanced levels of soluble phenolic compounds after 12 h post-inoculation (hpi), while amounts of cell wall bound phenolics were similar in inoculated and control plants. Other early responses activated by REC3 (at 24 hpi) were a decline of lipid peroxidation and up-regulation of strawberry genes involved in defence (FaPR1), bacterial recognition (FaFLS2) and H₂O₂ depuration (FaCAT and FaAPXc). The last may explain the apparent absence of oxidative burst in leaves after bacterial inoculation. Also, REC3 inoculation induced delayed structural responses such as callose deposition and cell wall fortification (at 72 hpi). Results showed that A. brasilense REC3 is capable of exerting beneficial effects on strawberry plants, reinforcing their physiological and cellular characteristics, which in turns contribute to improve plant performance.

  15. Uso del biofertilizante Azospirillum como fuente alternativa para la fertilización nitrogenada de la caña de azúcar

    Directory of Open Access Journals (Sweden)

    Everaldo Becerra-De Armas

    2014-01-01

    Full Text Available El presente trabajo se desarrolló sobre un suelo Pardo Sialítico Típico con el objetivo de validar la efectividad del biofertilizante Azospirillum, Cepa 8 INICA, con una concentración 109 UFC/mL en áreas cañeras de producción. Se utilizaron dos métodos de aplicación: asperjado con arrope y enterrado. Se empleó la variedad C86-12, cepa R1. Los parámetros altura, diámetro, conteo de tallos y hojas activas fueron evaluados a los 3 meses de edad. Los datos de rendimiento se obtuvieron a partir del pesaje real de la caña en el momento de la cosecha. En las evaluaciones realizadas se pudo observar que existe una mayor altura, diámetro y número de hojas activas en los tratamientos donde se utilizó el método asperjado. Para la variable conteo de tallos los mejores resultados se alcanzaron al enterrar el biofertilizante. En el caso del rendimiento agrícola, los valores siempre fueron mayores en los tratamientos donde se aplicó Azospirillum respecto al testigo (NPK SERFE, con resultados satisfactorios cuando se utilizó el método enterrado, y una dosis 75 l/ha de Azospirillum + el 40% de Nitrógeno, según dosis del SERFE.

  16. Desempenho agronômico a campo de híbridos de milho inoculados com Azospirillum

    Directory of Open Access Journals (Sweden)

    Patricia Dörr de Quadros

    2014-04-01

    Full Text Available O uso de inoculantes na cultura do milho tem sido cada vez mais valorizado, em vista dos benefícios que pode trazer à cultura, como a fixação biológica do nitrogênio e o aumento da quantidade de raízes. Isto pode melhorar a absorção de água e nutrientes pela planta, contribuindo para o desenvolvimento do milho, principalmente em períodos de seca. Este estudo foi desenvolvido com o objetivo de avaliar, em condições de campo, as características agronômicas e o rendimento de grãos de híbridos de milho, inoculados, ou não, com uma mistura de três espécies de Azospirillum (A. brasilense, A. lipoferum, A. oryzae. Foram avaliados o teor relativo de clorofila nas folhas, a altura de planta, a senescência foliar, os componentes de rendimento de grãos, o teor de N, a matéria seca da parte aérea das plantas e o número mais provável de bactérias diazotróficas na rizosfera das plantas. A inoculação manteve o teor de clorofila significativamente maior até o estádio R3 das plantas, para os três híbridos testados, aumentou o rendimento da matéria seca da parte aérea, dos híbridos AS 1575 e SHS 5050, o peso de 1000 grãos, para o híbrido P32R48 e altura, para o AS 1575. Houve interação entre os genótipos de milho e as bactérias inoculadas, visto que, cada híbrido testado respondeu de forma diferente à inoculação. A inoculação de Azospirillum em milho demonstrou estimular o desenvolvimento das plantas no período vegetativo, aumentando a probabilidade de obter-se um estande de plantas uniforme, maior resistência ao estresse e maior concentração de clorofila nas folhas.

  17. pVLT-EGFP载体构建及其在巴西固氮螺菌(Azospirillum brasilense)的表达研究%Construction of an Expression Vector pVLT-EGFP and Its Expression in Azospirillum brasilense

    Institute of Scientific and Technical Information of China (English)

    巩涛; 王继雯; 杨文玲; 甄静; 刘莹莹; 李冠杰; 刘莉; 岳丹丹; 陈国参

    2015-01-01

    为了研究巴西固氮螺菌(Azospirillum brasilense)在植物体内的定殖,利用酶切连接的方法,以增强型绿色荧光蛋白(enhanced green fluorescent protein,EGFP)基因与表达栽体pVLT-33为基本元件,构建了重组表达载体pVLT-EGFP,电转巴西固氮螺菌R7细胞,并利用实时荧光定量PCR(qPCR)研究了不同温度、不同时间EGFP mRNA的表达情况.酶切及测序结果表明,成功构建了pVLT-EGFP载体,并在荧光显微镜下观察到绿色荧光蛋白表达;qPCR结果显示:30℃,诱导9hEGFP基因的表达水平最高.本研究成功构建了重组表达载体pVLT-EGFP,为实现pVLT-EGFP的可控表达及研究固氮菌在植物体内的定殖规律及促生长机理提供了一种有效的途径.

  18. Surface colonization by Azospirillum brasilense SM in the indole-3-acetic acid dependent growth improvement of sorghum.

    Science.gov (United States)

    Kochar, Mandira; Srivastava, Sheela

    2012-04-01

    The key to improving plant productivity is successful bacterial-plant interaction in the rhizosphere that can be maintained in the environment. The results presented here confirm Azospirillum brasilense strain SM as a competent plant growth promoting bacterium over mid- and long-term associations with sorghum. This study establishes that plant growth can be directly correlated with the associated bacterium's indole-3-acetic acid (IAA) production capability as IAA over-expressing variants, SMp30 and SMΔi3-6 fared better than the wild type strain. The auxin antagonist, p-chlorophenoxy isobutyric acid confirmed the role of bacterial IAA in plant growth promotion and verified the presence of larger amount of IAA available to the seeds on inoculation with IAA over-expressing mutants. Microscopic analysis identified the bacterial association at root tips, root-shoot junction and elongation zone and their surface colonizing nature. Scanning electron microscopy identified larger number of root hairs and extensive exopolysaccharide covering in comparison to untreated ones. In addition, vibroid-shaped Azospirilla attached by means of fibrillar material were dispersed along the elongation zone. The notable difference with IAA over-expressing variants was enhanced number of root hairs. Thus, the variant strains may be more efficient surface colonizers of the sorghum root and used as superior bio-inoculants for improving plant productivity.

  19. Enhanced accumulation of starch and total carbohydrates in alginate-immobilized Chlorella spp. induced by Azospirillum brasilense: II. Heterotrophic conditions.

    Science.gov (United States)

    Choix, Francisco J; de-Bashan, Luz E; Bashan, Yoav

    2012-10-10

    The effect of the bacterium Azospirillum brasilense jointly immobilized with Chlorella vulgaris or C. sorokiniana in alginate beads on total carbohydrates and starch was studied under dark and heterotrophic conditions for 144 h in synthetic growth medium supplemented with either d-glucose or Na-acetate as carbon sources. In all treatments, enhanced total carbohydrates and starch content per culture and per cell was obtained after 24h; only jointly immobilized C. vulgaris growing on d-glucose significantly increased total carbohydrates and starch content after 96 h. Enhanced accumulation of carbohydrate and starch under jointly immobilized conditions was variable with time of sampling and substrate used. Similar results occurred when the microalgae was immobilized alone. In both microalgae growing on either carbon sources, the bacterium promoted accumulation of carbohydrates and starch; when the microalgae were immobilized alone, they used the carbon sources for cell multiplication. In jointly immobilized conditions with Chlorella spp., affinity to carbon source and volumetric productivity and yield were higher than when Chlorella spp. were immobilized alone; however, the growth rate was higher in microalgae immobilized alone. This study demonstrates that under heterotrophic conditions, A. brasilense promotes the accumulation of carbohydrates in two strains Chlorella spp. under certain time-substrate combinations, producing mainly starch. As such, this bacterium is a biological factor that can change the composition of compounds in microalgae in dark, heterotrophic conditions.

  20. Enhanced accumulation of starch and total carbohydrates in alginate-immobilized Chlorella spp. induced by Azospirillum brasilense: I. Autotrophic conditions.

    Science.gov (United States)

    Choix, Francisco J; de-Bashan, Luz E; Bashan, Yoav

    2012-10-10

    The effect of the microalgae-growth promoting bacterium Azospirillum brasilense on accumulation of total carbohydrates and starch in two species of Chlorella (Chlorella vulgaris and Chlorella sorokiniana), when the bacterium and each microalga were jointly immobilized in alginate beads was studied under autotrophic conditions for 144 h in synthetic medium. The interaction of the bacterium with the microalgae enhanced accumulation of total carbohydrate and starch. Cells of Chlorella accumulated the highest amounts of carbohydrate after incubation for 24h. Yet, this did not coincide with the highest affinity and volumetric productivity measured in these cultures. However, after incubation for 72 h, mainly in jointly immobilized treatments of both microalgae species, the cultures reached their highest total carbohydrate content (mainly as starch) and also the highest affinity and volumetric productivity. These results demonstrate the potential of A. brasilense to affect carbohydrates and starch accumulation in Chlorella spp. when both microorganisms are co-cultured, which can be an important tool for applications of microalgae.

  1. Migration of Azospirillum brasilense Yu62 from Root to Stem and Leaves Inside Rice and Tobacco Plants

    Institute of Scientific and Technical Information of China (English)

    CHIFeng; SHENShi-Hua; CHENSan-Feng; JINGYu-Xiang

    2004-01-01

    Azospirillum brasilense Tarrand, Krieg et Doebereiner is one of the important plant growthpromotion endophytes. A. brasilense Yu62 tagged with gfp gene was inoculated into roots of rice and tobacco seedlings, which were then, cultured in gnotobiotic condition. At a certain days after inoculation the different portions of the seedling were observed under laser confocal microscope, resulting in that A.brasilense Yu62 bacteria were colonized in epidermal and cortical cells, intercellular spaces and vascular system of stem and leaf tissue interiors besides in roots. Higher populations of the bacteria isolated from roots, stems and leaves indicated that A. brasilense Yu62 bacteria could ascend themselves from roots to stems and leaves of rice and tobacco. This observation lays down the foundation for ecology and cell morphology of bacterial migration inside plants, interaction between A. brasilense Yu62 bacteria and host cells as well as the plant-growth promotion, provides scientific basis for further application, and is of importance in science and practice.

  2. Activity of two catabolic enzymes of the phosphogluconate pathway in mesquite roots inoculated with Azospirillum brasilense Cd.

    Science.gov (United States)

    Leyva, Luis A; Bashan, Yoav

    2008-10-01

    The mesquite amargo (Prosopis articulate), one of the main nurse trees of the Sonoran Desert in Mexico, is responsible for major, natural re-vegetation processes. It exudes gluconic acid in root exudates, a favorite carbon source for the plant growth-promoting bacterium Azospirillum brasilense. Two enzymes, gluconokinase (EC 2.7.1.12) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44), participating in the phosphogluconate pathway, are active in the bacteria. Bacterial 6-phosphogluconate dehydrogenase is a constitutive enzyme, while gluconokinase is induced upon exposure to gluconic acid. Both enzymes are active in young, non-inoculated mesquite seedlings growing under hydroponic conditions. When A. brasilense Cd bacteria are inoculated on the root system, the roots exhibit much higher activity of gluconokinase, but not 6-phosphogluconate dehydrogenase. Mesquite roots exhibit high levels of root colonization by the inoculating bacteria. At the same time, and also for plants growing under sand culture conditions, the seedlings grew taller, greener, had longer leaves, and were heavier.

  3. Structure and thermodynamics of effector molecule binding to the nitrogen signal transduction PII protein GlnZ from Azospirillum brasilense.

    Science.gov (United States)

    Truan, Daphné; Bjelić, Saša; Li, Xiao-Dan; Winkler, Fritz K

    2014-07-29

    The trimeric PII signal transduction proteins regulate the function of a variety of target proteins predominantly involved in nitrogen metabolism. ATP, ADP and 2-oxoglutarate (2-OG) are key effector molecules influencing PII binding to targets. Studies of PII proteins have established that the 20-residue T-loop plays a central role in effector sensing and target binding. However, the specific effects of effector binding on T-loop conformation have remained poorly documented. We present eight crystal structures of the Azospirillum brasilense PII protein GlnZ, six of which are cocrystallized and liganded with ADP or ATP. We find that interaction with the diphosphate moiety of bound ADP constrains the N-terminal part of the T-loop in a characteristic way that is maintained in ADP-promoted complexes with target proteins. In contrast, the interactions with the triphosphate moiety in ATP complexes are much more variable and no single predominant interaction mode is apparent except for the ternary MgATP/2-OG complex. These conclusions can be extended to most investigated PII proteins of the GlnB/GlnK subfamily. Unlike reported for other PII proteins, microcalorimetry reveals no cooperativity between the three binding sites of GlnZ trimers for any of the three effectors under carefully controlled experimental conditions.

  4. Identification and characterization of the two-component NtrY/NtrX regulatory system in Azospirillum brasilense

    Directory of Open Access Journals (Sweden)

    M.L. Ishida

    2002-06-01

    Full Text Available Two Azospirillum brasilense open reading frames (ORFs exhibited homology with the two-component NtrY/NtrX regulatory system from Azorhizobium caulinodans. These A. brasilense ORFs, located downstream to the nifR3ntrBC operon, were isolated, sequenced and characterized. The present study suggests that ORF1 and ORF2 correspond to the A. brasilense ntrY and ntrX genes, respectively. The amino acid sequences of A. brasilense NtrY and NtrX proteins showed high similarity to sensor/kinase and regulatory proteins, respectively. Analysis of lacZ transcriptional fusions by the ß-galactosidase assay in Escherichia coli ntrC mutants showed that the NtrY/NtrX proteins failed to activate transcription of the nifA promoter of A. brasilense. The ntrYX operon complemented a nifR3ntrBC deletion mutant of A. brasilense for nitrate-dependent growth, suggesting a possible cross-talk between the NtrY/X and NtrB/C sensor/regulator pairs. Our data support the existence of another two-component regulatory system in A. brasilense, the NtrY/NtrX system, probably involved in the regulation of nitrate assimilation.

  5. Enhanced activity of ADP glucose pyrophosphorylase and formation of starch induced by Azospirillum brasilense in Chlorella vulgaris.

    Science.gov (United States)

    Choix, Francisco J; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E

    2014-05-10

    ADP-glucose pyrophosphorylase (AGPase) regulates starch biosynthesis in higher plants and microalgae. This study measured the effect of the bacterium Azospirillum brasilense on AGPase activity in the freshwater microalga Chlorella vulgaris and formation of starch. This was done by immobilizing both microorganisms in alginate beads, either replete with or deprived of nitrogen or phosphorus and all under heterotrophic conditions, using d-glucose or Na-acetate as the carbon source. AGPase activity during the first 72h of incubation was higher in C. vulgaris when immobilized with A. brasilense. This happened simultaneously with higher starch accumulation and higher carbon uptake by the microalgae. Either carbon source had similar effects on enzyme activity and starch accumulation. Starvation either by N or P had the same pattern on AGPase activity and starch accumulation. Under replete conditions, the population of C. vulgaris immobilized alone was higher than when immobilized together, but under starvation conditions A. brasilense induced a larger population of C. vulgaris. In summary, adding A. brasilense enhanced AGPase activity, starch formation, and mitigation of stress in C. vulgaris.

  6. Cloning and characterisation of the Azospirillum brasilense glnD gene and analysis of a glnD mutant.

    Science.gov (United States)

    Van Dommelen, A; Keijers, V; Somers, E; Vanderleyden, J

    2002-01-01

    Nitrogen regulation in bacteria involves the capacity to sense the availability of fixed nitrogen and to translate a signal indicating nitrogen deficiency or nitrogen excess into a cellular response. One of the key enzymes in this complex regulation process, the uridylyltransferase/uridylyl-removing (UTase) enzyme, encoded by the glnD gene, was characterised in the diazotroph Azospirillum brasilense, which promotes plant growth. The glnD gene product is responsible for the uridylylation of both P(II)-like nitrogen regulatory proteins, P(II) and P(Z), depending on the nitrogen status of the cell. The nitrogen-regulated activity of the main ammonium-assimilating enzyme, glutamine synthetase, is not altered in a glnD-Tn 5-B30 insertion mutant. UTase influences processes that are regulated by the NtrB-NtrC two-component histidine protein kinase system, such as ammonium uptake and nitrate assimilation. Moreover, the glnD gene product is indispensable for the activation of nitrogen fixation. Transcription of glnD is up-regulated under nitrogen-fixing conditions. This regulation is only partially dependent on the global nitrogen regulation (Ntr) system.

  7. Interaction between GInB and the N-terminal domain of NifA in Azospirillum brasilense

    Institute of Scientific and Technical Information of China (English)

    ZHOU XiaoYu; ZOU XiaoXiao; LI JiLun

    2008-01-01

    Azospirillum brasilense is a diazotroph associated with many important agricultural crops and shows potential as a biofertilizer. NifA, the transcriptional activator of nitrogen fixation (nif) genes, and GInB, one of P,, signal transduction family protein, are key proteins in the regulation of nitrogen fixation in A. brasilense. It was previously reported that the regulation of NifA activity in A. brasilense depends on GInB. We report here that GInB was found to interact directly with the N-terminal domain of NifA in vivo under nitrogen-free conditions and the N-terminal mutant of NifA in which the Tyr residues at position 18 and 53 were replaced by Phe (NifA-N-Y18/53F) strengthened the interaction with GInB. Moreover, we also found that the amino acid residues 66-88 and 165-176 in N-terminus of NifA are responsible for the interaction with GInB.

  8. Influence of the ADP/ATP ratio, 2-oxoglutarate and divalent ions on Azospirillum brasilense PII protein signalling.

    Science.gov (United States)

    Gerhardt, Edileusa C M; Araújo, Luíza M; Ribeiro, Ronny R; Chubatsu, Leda S; Scarduelli, Marcelo; Rodrigues, Thiago E; Monteiro, Rose A; Pedrosa, Fábio O; Souza, Emanuel M; Huergo, Luciano F

    2012-06-01

    Proteins belonging to the P(II) family coordinate cellular nitrogen metabolism by direct interaction with a variety of enzymes, transcriptional regulators and transporters. The sensing function of P(II) relies on its ability to bind the nitrogen/carbon signalling molecule 2-oxoglutarate (2-OG). In Proteobacteria, P(II) is further subject to reversible uridylylation according to the intracellular levels of glutamine, which reflect the cellular nitrogen status. A number of P(II) proteins have been shown to bind ADP and ATP in a competitive manner, suggesting that P(II) might act as an energy sensor. Here, we analyse the influence of the ADP/ATP ratio, 2-OG levels and divalent metal ions on in vitro uridylylation of the Azospirillum brasilense P(II) proteins GlnB and GlnZ, and on interaction with their targets AmtB, DraG and DraT. The results support the notion that the cellular concentration of 2-OG is a key factor governing occupation of the GlnB and GlnZ nucleotide binding sites by ATP or ADP, with high 2-OG levels favouring the occupation of P(II) by ATP. Both P(II) uridylylation and interaction with target proteins responded to the ADP/ATP ratio within the expected physiological range, supporting the concept that P(II) proteins might act as cellular energy sensors.

  9. Regulation of glnB gene promoter expression in Azospirillum brasilense by the NtrC protein.

    Science.gov (United States)

    Huergo, Luciano F; Souza, Emanuel M; Steffens, M Berenice R; Yates, M Geoffrey; Pedrosa, Fabio O; Chubatsu, Leda S

    2003-06-01

    In Azospirillum brasilense the glnB and glnA genes are clustered in an operon regulated by three different promoters: two located upstream of glnB (glnBp1-sigma(70), and glnBp2-sigma(N)) and one as yet unidentified promoter, in the glnBA intergenic region. We have investigated the expression of the glnB gene promoter using glnB-lacZ gene fusions, mutation analysis, heterologous expression and DNA band-shift assays. Deletion of the glnB promoter region showed that NtrC-binding sequences were essential for glnB expression under nitrogen limitation. The A. brasilense NtrC protein activated transcription of glnB-lacZ fusions in the heterologous genetic background of Escherichia coli. Expression of glnB-lacZ fusions in two A. brasilense ntrC mutants differed from that in the wild-type strain. In vitro studies also indicated that the purified NtrC protein from E. coli was able to bind to the glnB promoter region of A. brasilense. Our results show that the NtrC protein activates glnBglnA expression under nitrogen limitation in A. brasilense.

  10. EVALUACIÓN DE CEPAS NATIVAS DEL GÉNERO Azospirillum Y SU INTERACCIÓN CON EL CULTIVO DEL ARROZ

    OpenAIRE

    Mabel Pazos; Annia Hernández

    2001-01-01

    Catorce cepas nativas pertenecientes a la especie Azospirillum brasilense se caracterizaron en cuanto a su ca- pacidad de fijar el nitrógeno atmosférico. Se estudió su efecto en el cultivo del arroz (Oryza sativa), mediante el modelo Microcosmos, realizando determinaciones de la altura de las plantas inoculadas, masa fresca de la raíz y el contenido de fenoles libres y la cuantificación de proteínas en las hojas. Se observó en todos los casos un efecto positivo por la inocula- ción con e...

  11. Structural analysis of the O-polysaccharide of the lipopolysaccharide from Azospirillum brasilense Jm6B2 containing 3-O-methyl-D-rhamnose (D-acofriose).

    Science.gov (United States)

    Boyko, Alevtina S; Dmitrenok, Andrey S; Fedonenko, Yuliya P; Zdorovenko, Evelina L; Konnova, Svetlana A; Knirel, Yuriy A; Ignatov, Vladimir V

    2012-07-01

    Two types of neutral O-polysaccharides were obtained by mild acid degradation of the lipopolysaccharide isolated by phenol-water extraction from the asymbiotic diazotrophic rhizobacterium Azospirillum brasilense Jm6B2. The following structure of the major O-polysaccharide was established by composition and methylation (ethylation) analyses, Smith degradation, and 1D and 2D (1)H and (13)C NMR spectroscopy: [structure: see text] where a non-stoichiometric (~60%) 3-O-methylation of D-rhamnose is indicated by italics.

  12. Actividad nitrogenasa, producción de fitohormonas, sideróforos y antibiosis en cepas de Azospirillum y Klebsiella aisladas de maíz y teocintle

    OpenAIRE

    Moisés Graciano Carcaño-Montiel; Ronald Ferrera-Cerrato; Jesús Pérez-Moreno; José D. Molina-Galán; Yoav Bashan

    2006-01-01

    Las bacterias de los géneros Azospirillum y Klebsiella, conocidas como rizobacterias promotoras del crecimiento vegetal, son fijadoras de nitrógeno y productoras de sustancias reguladoras del crecimiento, por lo que ejercen un efecto benéfico en las plantas con las cuales interaccionan. Esta asociación microorganismo-planta puede mejorar el crecimiento de los cultivos a través de la combinación de fijación biológica de nitrógeno, producción de sustancias hormonales, incremento de la disponi...

  13. Desenvolvimento vegetativo do arroz irrigado afetado pela inoculação com Azospirillum e aplicação de nitrogênio mineral

    OpenAIRE

    Bianchet, Paula; Sangoi, Luis; Souza, Clovis Arruda de; Klauberg Filho, Osmar; Panison, Fernanda

    2015-01-01

    O nitrogênio é o nutriente absorvido em maior quantidade pelo arroz. A associação com bactérias diazototróficas pode contribuir com o suprimento de N da cultura. O objetivo deste trabalho foi avaliar o efeito da inoculação de isolados de bactérias diazotróficas do gênero Azospirillum e da aplicação de doses crescentes de N mineral sobre o desenvolvimento vegetativo de cultivares de arroz irrigado cultivadas no sistema pré-germinado. O experimento foi implantado em casa de vegetação, num delin...

  14. Detecção de Azospirillum amazonense em raízes e rizosfera de orchidaceae e de outras famílias vegetais

    OpenAIRE

    Lange, A.; F. M. S. Moreira

    2002-01-01

    Azospirillum amazonense é uma bactéria fixadora de N2 atmosférico de ampla ocorrência, principalmente em associações radiculares com gramíneas e palmeiras. Para verificar sua presença em outras espécies vegetais, ainda não estudadas, e a eficiência de meios para sua detecção, foram testados os meios Fam e LGI para contagens em solo rizosférico ou em culturas de enriquecimento com solo rizosférico, ecto e endorrizosfera. A. amazonense foi detectada no solo rizosférico, ecto e endorrizosfera de...

  15. Toxicidade de herbicidas utilizados na cultura da cana-de-açúcar à bactéria diazotrófica Azospirillum brasilense Toxicity of herbicides applied on sugarcane to the diazotrophic bacterium Azospirillum brasilense

    Directory of Open Access Journals (Sweden)

    S.O Procópio

    2011-01-01

    Full Text Available Objetivou-se neste trabalho identificar herbicidas utilizados na cultura da cana-de-açúcar que não alteram o crescimento ou a capacidade de fixação biológica de nitrogênio (FBN da bactéria diazotrófica Azospirillum brasi lense. Dezoito herbicidas - paraquat, ametryn, amicarbazone, diuron, metribuzin, [hexazinone + diuron], [hexazinone + clomazone], clomazone, isoxaflutole, sulfentrazone, oxyfluorfen, imazapic, imazapyr, [trifloxysulfuron-sodium + ametryn], S-metolachlor, glyphosate, MSMA e 2,4-D - foram testados em suas doses comerciais quanto ao impacto sobre o crescimento da bactéria em meio líquido DIGs. As variáveis capacidade de suporte de crescimento (carrying capacity do meio de cultura, duração da fase lag e tempo de geração de A. brasilense foram calculadas a partir de dados de densidade ótica obtidos, em intervalos regulares, durante a incubação de culturas por 55 h. O impacto dos herbicidas na atividade da nitrogenase de A. brasilense foi avaliado em meio semissólido NFb, sem N, pela técnica da atividade de redução do acetileno (ARA. Os efeitos dos herbicidas sobre as variáveis de crescimento e ARA foram comparados ao controle pelo teste de Dunnett. Paraquat, oxyfluorfen, [trifloxysulfuron-sodium + ametryn] e glyphosate reduziram a capacidade do meio DIGs em suportar o crescimento de A. brasilense. Esse efeito foi associado ao aumento da duração da fase lag e do tempo de geração para [trifloxysulfuron-sodium + ametryn] e ao aumento no tempo de geração para glyphosate. MSMA, paraquat e amicarbazone reduzem a FBN in vitro de A. brasilense, porém essa redução é mais severa na presença do paraquat. Os demais herbicidas não alteram o crescimento e a FBN de A. brasilense.The objective of this work was to identify the herbicides applied on sugarcane that do not affect the growth nor the process of biological nitrogen fixation (BNF of the diazotrophic bacterium Azospirillum brasilense. Commercial doses of

  16. Residual effect of nitrogen fertilization and Azospirillum brasilense inoculation in the maize cultureEfeito residual da adubação nitrogenada e inoculação de Azospirillum brasilense na cultura do milho

    Directory of Open Access Journals (Sweden)

    Jackson Huzar Novakowiski

    2011-12-01

    Full Text Available The diazotrophic bacteria Azospirillum brasilense is an organism able to fix nitrogen of atmosphere and produce plant hormones. Nevertheless, there is lack of information with regard to use in field conditions, especially in production systems that have presence of animals in a determined year period. The objective of paper was to evaluate the association of the nitrogen residual effect of fertilization in pasture winter and the inoculation with A. brasilense in the maize culture. Were carried two experiments in Guarapuava (PR in season 2008/09 with randomized block design with split plots in three replication. The main parcel consisted of application 5 levels of N (0, 75, 150, 225 e 300 kg ha-1 in pasture of black oat and ryegrass occupied by bovines and 4 treatments in the maize (T1 = control; T2 = inoculation of A. brasilense; T3 = 75 kg ha-1 of N; T4 = 150 kg ha-1 of N. Were evaluated: plants population, ears per plant, productivity, mass thousand grains, damage grains, row per ear and grains per row. There was residual effect of nitrogen applied in the pasture on maize culture. The mass thousand grains and the number of rows per ear of maize presented quadratic response for increase of nitrogen level in the pasture. The inoculation of A. brasilense provided higher productivity than control same with increase the nitrogen level applied in the pasture, with quadratic response in the experiment 1 and linear in the experiment 2.A bactéria diazotrófica Azospirillum brasilense é um organismo capaz de fixar nitrogênio da atmosfera e produzir hormônios vegetais. No entanto, há carência de informações a respeito de seu uso em condições de campo, sobretudo em sistemas de produção que tem a presença de animais em um determinado período do ano. O objetivo do trabalho foi avaliar a associação do efeito residual da adubação nitrogenada na pastagem de inverno e a inoculação de A. brasilense na cultura do milho. Foram conduzidos dois

  17. Produtividade do milho em resposta à aplicação de nitrogênio e inoculação das sementes com Azospirillum spp Corn produntivity in response to nitrogen application and seed inoculation with Azospirillum spp

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    Luiz Ermindo Cavallet

    2000-04-01

    Full Text Available Em experimento de campo, nas condições de plantio direto em Latossolo Vermelho eutroférrico de fertilidade média a alta, foram testados para o milho (Zea mays, cv. G-159 S da Ciba Sementes no período de outubro/1997 a março/1998, o aumento de produtividade de grãos, o comprimento de espiga, a altura de plantas e o número de linhas de grão por espiga, por conseqüência da inoculação das sementes com o produto biotecnológico comercial denominado "Graminante", à base de Azospirillum spp. Os tratamentos consistiram em ausência e presença de inoculação de "Graminante", com e sem aplicação de nitrogênio tanto, da semeadura (70 kg ha-1 como em cobertura (70 kg ha-1 consistindo, deste modo, numa distribuição fatorial 2 x 2 x 2, em quatro repetições. A inoculação do "Graminante" aumentou significativamente a produtividade média de grãos, de 5211 para 6067 kg ha-1, ou seja, aumento de 17%, e aumentou o comprimento médio das espigas, de 13,6 para 14,4 cm; a inoculação do "Graminante" não teve efeito sobre o número de linhas de grão por espiga e altura de plantas. A aplicação de nitrogênio na semeadura e/ou em cobertura, não causou efeito sobre a produtividade do milho.An evaluation of corn productivity, cob length, plant height and number of corn lines on the cob as a result of nitrogen application and seed inoculation with Azospirillum spp. ("Graminante" was conducted from October 1997 to March 1998. The experiment was carried out on a high fertility Oxisol using Zea mays L. cv. G-1595 (Ciba under no-tillage in a 2 x 2 x 2 factorial design representing application and non-application of nitrogen at planting (70 kg ha-1, application and non-application of broadcast nitrogen (70 kg ha-1 and presence or absence of seed inoculation with four replications. Results showed that with seed inoculation the corn productivity increased by 17% (from 5211 to 6067 kg ha-1 while corn cob length increased from 13.6 to 14.4 cm. On the

  18. Control of Branchionus sp. and Amoeba sp. in cultures of Arthrospira sp. Control de Branchionus sp. y Amoeba sp. en cultivos de Arthrospira sp.

    OpenAIRE

    Carlos Méndez; Eduardo Uribe

    2012-01-01

    Cultivation of cyanobacterium Arthrospira sp. has been developed in many countries for the production of proteins, pigments and other compounds. Outdoor mass cultures are often affected by biological contamination, drastically reducing productivity as far as bringing death. This study evaluates the control of Branchionus sp. and Amoeba sp. with two chemical compounds: urea (U) and ammonium bicarbonate (AB), in laboratory conditions and outdoor mass culture of Arthrospira sp. The lethal concen...

  19. INOCULAÇÃO DE Azospirillum brasilense NA QUALIDADE FISIOLÓGICA DE SEMENTES DE MILHO DOCE

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    SOUZA, Epitácio José de

    2014-06-01

    Full Text Available The aimed of this study was to survey the physiological quality of sweet corn seeds submitted to inoculation of Azospirillum brasilense in different periods and dilutions in water. The experiment was conducted on the entirely randomized design with four replications in a factorial (4 x 4 more a witness without inoculation of A. brasilense. Were evaluated four periods between the inoculation and installation of the tests (0, 24, 48 and 72 hours and four dilutions of the inoculant in water (1:0, 1:1, 1:2 and 1:3. Were utilized seeds of sweet corn evaluated Tropical Plus hybrids and commercial strains of A. brasilense Ab-Ab-V5 and V6, in the dose of the commercial product 4 mL kg-1 seed. The parameters evaluated were germination, first count of germination, percentage of abnormal seeds, emergency, emergency speed index, length of epicotyl and of root, mass of the dry matter of shoots and of root. The dilution of A. brasilense in water did not affect no one parameter evaluated on the seeds of sweet corn, and the increase in the time between inoculation and the installation of the tests provide reduction on the first count of germination, speed emergency index and mass of dry matter of roots. It is concluded that, under laboratory conditions, inoculation of A. brasilense not benefits to germination and seed vigor of sweet corn. Objetivou-se avaliar a qualidade fisiológica de sementes de milho doce submetidas à inoculação de Azospirillum brasilense em diferentes períodos e diluições em água. O experimento foi conduzido no delineamento inteiramente casualizado, com quatro repetições em esquema fatorial (4 x 4, mais uma testemunha que não recebeu inoculação de A. brasilense. Foram avaliados quatro períodos entre a inoculação e a instalação dos testes (0, 24, 48 e 72 horas e quatro diluições do inoculante em água (1:0, 1:1, 1:2 e 1:3. Foram utilizadas sementes de milho doce híbrido comercial Tropical Plus e as estirpes de A

  20. Increased Salinity Tolerance of Cowpea Plants by Dual Inoculation of an Arbuscular Mycorrhizal Fungus Glomus clarum and a Nitrogen-fixer Azospirillum brasilense.

    Science.gov (United States)

    Rabie, G H; Aboul-Nasr, M B; Al-Humiany, A

    2005-03-01

    Pot greenhouse experiments were carried out to attempt to increase the salinity tolerance of one of the most popular legume of the world; cowpea; by using dual inoculation of an Am fungus Glomus clarum and a nitrogen-fixer Azospirillum brasilense. The effect of these beneficial microbes, as single- or dual inoculation-treatments, was assessed in sterilized loamy sand soil at five NaCl levels (0.0~7.2 ds/m) in irrigating water. The results of this study revealed that percentage of mycorrhizal infection, plant height, dry weight, nodule number, protein content, nitrogenase and phosphatase activities, as well as nutrient elements N, P, K, Ca, Mg were significantly decreased by increasing salinity level in non-mycorrhized plants in absence of NFB. Plants inoculated with NFB showed higher nodule numbers, protein content, nitrogen concentration and nitrogenase activities than those of non-inoculated at all salinity levels. Mycorrhized plants exhibited better improvement in all measurements than that of non-mycorrhized ones at all salinity levels, especially, in the presence of NFB. The concentration of Na(+) was significantly accumulated in cowpea plants by rising salinity except in shoots of mycorrhizal plants which had K(+)/Na(+) ratios higher than other treatments. This study indicated that dual inoculation with Am fungi and N-fixer Azospirillum can support both needs for N and P, excess of NaCl and will be useful in terms of soil recovery in saline area.

  1. Polyhydroxyalcanoates of strains of Azospirillum spp. isolated of roots of Lycopersicon esculentum Mill. “tomato” and Oryza sativa L. “rice” in Lambayeque

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    Katty Baca

    2010-12-01

    Full Text Available In this work was determined the concentration of polyhydroxyalkanoates (PHAs of Azospirillum strains isolated from roots of Lycopersicon esculentum Mill "tomato" and Oryza sativa L. "rice" as an alternative to accumulation of petroleum-based plastics. Previously disinfected root were plated in Nfb semisolid medium where nitrogen-fixing bacteria were recognized by a whitish film on the surface and turn from green to blue. The genus Azospirillum was identified in Congo red agar medium, obtained 96 isolates of A. lipoferum and A. brasilense on tomato and rice. Batch fermentation was performed with broth Azotobacter modified feeding a saturated solution of malic acid every 12 hours and were stained with Sudan Black B. Strains were selected with the greatest number of PHAs granules (in tomato, 18 of A. lipoferum and 2 of A. brasilense; in rice, 10 of A. lipoferum and 10 of A. brasilense and quantified the biomass and PHAs. PHAs concentration reached 0.661 gL-1 in A. lipoferum KM(T-73 and 0.738 gL-1 in A. brasilense KM(T-19, both isolated from tomato. Strains of A. lipoferum and A. brasilense isolated from tomato reached a higher concentration of biomass and PHAs against the strains of rice.

  2. Mutation in a D-alanine-D-alanine ligase of Azospirillum brasilense Cd results in an overproduction of exopolysaccharides and a decreased tolerance to saline stress.

    Science.gov (United States)

    Jofré, Edgardo; Fischer, Sonia; Príncipe, Analía; Castro, Marina; Ferrari, Walter; Lagares, Antonio; Mori, Gladys

    2009-01-01

    Bacteria of the genus Azospirillum are free-living nitrogen-fixing, rhizobacteria that are found in close association with plant roots, where they exert beneficial effects on plant growth and yield in many crops of agronomic importance. Unlike other bacteria, little is known about the genetics and biochemistry of exopolysaccharides in Azospirillum brasilense. In an attempt to characterize genes associated with exopolysaccharides production, we generated an A. brasilense Cd Tn5 mutant that showed exopolysaccharides overproduction, decreased tolerance to saline conditions, altered cell morphology, and increased sensitivity to detergents. Genetic characterization showed that the Tn5 was inserted within a ddlB gene encoding for a d-alanine-d-alanine ligase, and located upstream of the ftsQAZ gene cluster responsible for cell division in different bacteria. Heterologous complementation of the ddlB Tn5 mutant restored the exopolysaccharides production to wild-type levels and the ability to grow in the presence of detergents, but not the morphology and growth characteristics of the wild-type bacteria, suggesting a polar effect of Tn5 on the fts genes. This result and the construction of a nonpolar ddlB mutant provide solid evidence of the presence of transcriptional coupling between a gene associated with peptidoglycan biosynthesis and the fts genes required to control cell division.

  3. Involvement of indole-3-acetic acid produced by Azospirillum brasilense in accumulating intracellular ammonium in Chlorella vulgaris.

    Science.gov (United States)

    Meza, Beatriz; de-Bashan, Luz E; Bashan, Yoav

    2015-01-01

    Accumulation of intracellular ammonium and activities of the enzymes glutamine synthetase (GS) and glutamate dehydrogenase (GDH) were measured when the microalgae Chlorella vulgaris was immobilized in alginate with either of two wild type strains of Azospirillum brasilense or their corresponding indole-3-acetic acid (IAA)-attenuated mutants. After 48 h of immobilization, both wild types induced higher levels of intracellular ammonium in the microalgae than their respective mutants; the more IAA produced, the higher the intracellular ammonium accumulated. Accumulation of intracellular ammonium in the cells of C. vulgaris followed application of four levels of exogenous IAA reported for A. brasilense and its IAA-attenuated mutants, which had a similar pattern for the first 24 h. This effect was transient and disappeared after 48 h of incubation. Immobilization of C. vulgaris with any bacteria strain induced higher GS activity. The bacterial strains also had GS activity, comparable to the activity detected in C. vulgaris, but weaker than when immobilized with the bacteria. When net activity was calculated, the wild type always induced higher GS activity than IAA-attenuated mutants. GDH activity in most microalgae/bacteria interactions resembled GS activity. When complementing IAA-attenuated mutants with exogenous IAA, GS activity in co-immobilized cultures matched those of the wild type A. brasilense immobilized with the microalga. Similarity occurred when the net GS activity was measured, and was higher with greater quantities of exogenous IAA. It is proposed that IAA produced by A. brasilense is involved in ammonium uptake and later assimilation by C. vulgaris.

  4. The Azospirillum brasilense Che1 chemotaxis pathway controls swimming velocity, which affects transient cell-to-cell clumping.

    Science.gov (United States)

    Bible, Amber; Russell, Matthew H; Alexandre, Gladys

    2012-07-01

    The Che1 chemotaxis-like pathway of Azospirillum brasilense contributes to chemotaxis and aerotaxis, and it has also been found to contribute to regulating changes in cell surface adhesive properties that affect the propensity of cells to clump and to flocculate. The exact contribution of Che1 to the control of chemotaxis and flocculation in A. brasilense remains poorly understood. Here, we show that Che1 affects reversible cell-to-cell clumping, a cellular behavior in which motile cells transiently interact by adhering to one another at their nonflagellated poles before swimming apart. Clumping precedes and is required for flocculation, and both processes appear to be independently regulated. The phenotypes of a ΔaerC receptor mutant and of mutant strains lacking cheA1, cheY1, cheB1, or cheR1 (alone or in combination) or with che1 deleted show that Che1 directly mediates changes in the flagellar swimming velocity and that this behavior directly modulates the transient nature of clumping. Our results also suggest that an additional receptor(s) and signaling pathway(s) are implicated in mediating other Che1-independent changes in clumping identified in the present study. Transient clumping precedes the transition to stable clump formation, which involves the production of specific extracellular polysaccharides (EPS); however, production of these clumping-specific EPS is not directly controlled by Che1 activity. Che1-dependent clumping may antagonize motility and prevent chemotaxis, thereby maintaining cells in a metabolically favorable niche.

  5. Tryptophan, thiamine and indole-3-acetic acid exchange between Chlorella sorokiniana and the plant growth-promoting bacterium Azospirillum brasilense.

    Science.gov (United States)

    Palacios, Oskar A; Gomez-Anduro, Gracia; Bashan, Yoav; de-Bashan, Luz E

    2016-06-01

    During synthetic mutualistic interactions between the microalga Chlorella sorokiniana and the plant growth-promoting bacterium (PGPB) Azospirillum brasilense, mutual exchange of resources involved in producing and releasing the phytohormone indole-3-acetic acid (IAA) by the bacterium, using tryptophan and thiamine released by the microalga, were measured. Although increased activities of tryptophan synthase in C. sorokiniana and indole pyruvate decarboxylase (IPDC) in A. brasilense were observed, we could not detect tryptophan or IAA in the culture medium when both organisms were co-immobilized. This indicates that no extra tryptophan or IAA is produced, apart from the quantities required to sustain the interaction. Over-expression of the ipdC gene occurs at different incubation times: after 48 h, when A. brasilense was immobilized alone and grown in exudates of C. sorokiniana and at 96 h, when A. brasilense was co-immobilized with the microalga. When A. brasilense was cultured in exudates of C. sorokiniana, increased expression of the ipdC gene, corresponding increase in activity of IPDC encoded by the ipdC gene, and increase in IAA production were measured during the first 48 h of incubation. IAA production and release by A. brasilense was found only when tryptophan and thiamine were present in a synthetic growth medium (SGM). The absence of thiamine in SGM yielded no detectable IAA. In summary, this study demonstrates that C. sorokiniana can exude sufficient tryptophan and thiamine to allow IAA production by a PGPB during their interaction. Thiamine is essential for IAA production by A. brasilense and these three metabolites are part of a communication between the two microorganisms.

  6. Biofertilization with Azospirillum brasilense improves in vitro culture of Handroanthus ochraceus, a forestry, ornamental and medicinal plant.

    Science.gov (United States)

    Llorente, Berta E; Alasia, María A; Larraburu, Ezequiel E

    2016-01-25

    Biofertilization with plant growth-promoting rhizobacteria is a potential alternative to plant productivity. Here, in vitro propagation of Handroanthus ochraceus (yellow lapacho), a forest crop with high economic and environmental value, was developed using the Azospirillum brasilense strains Cd and Az39 during rhizogenesis. Epicotiles of in vitro plantlets were multiplied in Woody Plant Medium (WPM). For rooting, elongated shoots were transferred to auxin-free Murashige-Skoog medium with Gamborg's vitamins and WPM, both at half salt concentration (½MSG and ½WPM), and inoculated with Cd or Az39 at the base of each shoot. Anatomical studies were performed using leaves cleared and stained with safranin for optical microscopy and leaves and roots metalized with gold-palladium for scanning electron microscopy (SEM). In ½WPM auxin-free medium, A. brasilense Cd inoculation produced 55% of rooting, increased root fresh and dry weight (45% and 77%, respectively), and led to lower stomata size and density with similar proportion of open and closed stomata. Both strains selectively increased the size or density of glandular trichomes in ½MSG. Moreover, bacteria were detected on the root surface by SEM. In conclusion, the difference in H. ochraceus response to A. brasilense inoculation depends on the strain and the plant culture media. Cd strain enhanced rooting in auxin-free ½WPM and produced plantlets with features similar to those expected in ex vitro plants. This work presents an innovative in vitro approach using beneficial plant-microorganism interaction as an ecologically compatible strategy in plant biotechnology.

  7. Expression and characterization of an N-truncated form of the NifA protein of Azospirillum brasilense

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    C.Y. Nishikawa

    2012-02-01

    Full Text Available Azospirillum brasilense is a nitrogen-fixing bacterium associated with important agricultural crops such as rice, wheat and maize. The expression of genes responsible for nitrogen fixation (nif genes in this bacterium is dependent on the transcriptional activator NifA. This protein contains three structural domains: the N-terminal domain is responsible for the negative control by fixed nitrogen; the central domain interacts with the RNA polymerase σ54 co-factor and the C-terminal domain is involved in DNA binding. The central and C-terminal domains are linked by the interdomain linker (IDL. A conserved four-cysteine motif encompassing the end of the central domain and the IDL is probably involved in the oxygen-sensitivity of NifA. In the present study, we have expressed, purified and characterized an N-truncated form of A. brasilense NifA. The protein expression was carried out in Escherichia coli and the N-truncated NifA protein was purified by chromatography using an affinity metal-chelating resin followed by a heparin-bound resin. Protein homogeneity was determined by densitometric analysis. The N-truncated protein activated in vivo nifH::lacZ transcription regardless of fixed nitrogen concentration (absence or presence of 20 mM NH4Cl but only under low oxygen levels. On the other hand, the aerobically purified N-truncated NifA protein bound to the nifB promoter, as demonstrated by an electrophoretic mobility shift assay, implying that DNA-binding activity is not strictly controlled by oxygen levels. Our data show that, while the N-truncated NifA is inactive in vivo under aerobic conditions, it still retains DNA-binding activity, suggesting that the oxidized form of NifA bound to DNA is not competent to activate transcription.

  8. Biofertilization with Azospirillum brasilense improves in vitro culture of Handroanthus ochraceus, a forestry, ornamental and medicinal plant.

    Science.gov (United States)

    Llorente, Berta E; Alasia, María A; Larraburu, Ezequiel E

    2016-01-25

    Biofertilization with plant growth-promoting rhizobacteria is a potential alternative to plant productivity. Here, in vitro propagation of Handroanthus ochraceus (yellow lapacho), a forest crop with high economic and environmental value, was developed using the Azospirillum brasilense strains Cd and Az39 during rhizogenesis. Epicotiles of in vitro plantlets were multiplied in Woody Plant Medium (WPM). For rooting, elongated shoots were transferred to auxin-free Murashige-Skoog medium with Gamborg's vitamins and WPM, both at half salt concentration (½MSG and ½WPM), and inoculated with Cd or Az39 at the base of each shoot. Anatomical studies were performed using leaves cleared and stained with safranin for optical microscopy and leaves and roots metalized with gold-palladium for scanning electron microscopy (SEM). In ½WPM auxin-free medium, A. brasilense Cd inoculation produced 55% of rooting, increased root fresh and dry weight (45% and 77%, respectively), and led to lower stomata size and density with similar proportion of open and closed stomata. Both strains selectively increased the size or density of glandular trichomes in ½MSG. Moreover, bacteria were detected on the root surface by SEM. In conclusion, the difference in H. ochraceus response to A. brasilense inoculation depends on the strain and the plant culture media. Cd strain enhanced rooting in auxin-free ½WPM and produced plantlets with features similar to those expected in ex vitro plants. This work presents an innovative in vitro approach using beneficial plant-microorganism interaction as an ecologically compatible strategy in plant biotechnology. PMID:26255131

  9. Co-inoculation of Rhizobium tropici and Azospirillum brasilense in common beans grown under two irrigation depths

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    Amanda Ribeiro Peres²*

    2016-04-01

    Full Text Available ABSTRACT The alternative technique of co-inoculation or mixed inoculation with symbiotic and non-symbiotic bacteria has been studied in leguminous plants. However, there are few field studies with common beans and under the influence of the amount of irrigated water. Thus, the objective of this study was to evaluate the efficiency of inoculation and co-inoculation of common beans with Rhizobium tropici and Azospirillum brasilense under two irrigation depths. The experiment was carried out in the winter of 2012 and 2013, in Selvíria, state of Mato Grosso do Sul. The experimental design was composed of randomized blocks in split-plot scheme with two irrigation depths in the plots (recommended for common beans and 75% of the recommended and five forms of nitrogen (N supply in the split-plots (control non-inoculated with 40 kg ha- 1 of N in topdressing, 80 kg ha- 1 of N in topdressing, A. brasilense inoculation with 40 kg ha-1 of N in topdressing, R. tropici inoculation with 40 kg ha-1 of N in topdressing, and co-inoculation of A. brasilense and R. tropici with 40 kg ha- 1 of N in topdressing with four repetitions. Co-inoculation increased nodulation in the second year of cultivation. None of the evaluated treatments increased the grain yield in relation to non-inoculated control with 40 kg ha-1 of nitrogen in topdressing, which presented average yield of 2,200 kg ha-1. The use of 75% of the recommended irrigation depth provides similar grain yield to the recommended irrigation depth in common beans cropped in winter.

  10. Expression and characterization of an N-truncated form of the NifA protein of Azospirillum brasilense.

    Science.gov (United States)

    Nishikawa, C Y; Araújo, L M; Kadowaki, M A S; Monteiro, R A; Steffens, M B R; Pedrosa, F O; Souza, E M; Chubatsu, L S

    2012-02-01

    Azospirillum brasilense is a nitrogen-fixing bacterium associated with important agricultural crops such as rice, wheat and maize. The expression of genes responsible for nitrogen fixation (nif genes) in this bacterium is dependent on the transcriptional activator NifA. This protein contains three structural domains: the N-terminal domain is responsible for the negative control by fixed nitrogen; the central domain interacts with the RNA polymerase σ(54) co-factor and the C-terminal domain is involved in DNA binding. The central and C-terminal domains are linked by the interdomain linker (IDL). A conserved four-cysteine motif encompassing the end of the central domain and the IDL is probably involved in the oxygen-sensitivity of NifA. In the present study, we have expressed, purified and characterized an N-truncated form of A. brasilense NifA. The protein expression was carried out in Escherichia coli and the N-truncated NifA protein was purified by chromatography using an affinity metal-chelating resin followed by a heparin-bound resin. Protein homogeneity was determined by densitometric analysis. The N-truncated protein activated in vivo nifH::lacZ transcription regardless of fixed nitrogen concentration (absence or presence of 20 mM NH(4)Cl) but only under low oxygen levels. On the other hand, the aerobically purified N-truncated NifA protein bound to the nifB promoter, as demonstrated by an electrophoretic mobility shift assay, implying that DNA-binding activity is not strictly controlled by oxygen levels. Our data show that, while the N-truncated NifA is inactive in vivo under aerobic conditions, it still retains DNA-binding activity, suggesting that the oxidized form of NifA bound to DNA is not competent to activate transcription.

  11. Expression and characterization of an N-truncated form of the NifA protein of Azospirillum brasilense

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, C.Y.; Araújo, L.M.; Kadowaki, M.A.S.; Monteiro, R.A.; Steffens, M.B.R.; Pedrosa, F.O.; Souza, E.M.; Chubatsu, L.S. [Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, PR (Brazil)

    2012-01-27

    Azospirillum brasilense is a nitrogen-fixing bacterium associated with important agricultural crops such as rice, wheat and maize. The expression of genes responsible for nitrogen fixation (nif genes) in this bacterium is dependent on the transcriptional activator NifA. This protein contains three structural domains: the N-terminal domain is responsible for the negative control by fixed nitrogen; the central domain interacts with the RNA polymerase σ{sup 54} factor and the C-terminal domain is involved in DNA binding. The central and C-terminal domains are linked by the interdomain linker (IDL). A conserved four-cysteine motif encompassing the end of the central domain and the IDL is probably involved in the oxygen-sensitivity of NifA. In the present study, we have expressed, purified and characterized an N-truncated form of A. brasilense NifA. The protein expression was carried out in Escherichia coli and the N-truncated NifA protein was purified by chromatography using an affinity metal-chelating resin followed by a heparin-bound resin. Protein homogeneity was determined by densitometric analysis. The N-truncated protein activated in vivo nifH::lacZ transcription regardless of fixed nitrogen concentration (absence or presence of 20 mM NH{sub 4}Cl) but only under low oxygen levels. On the other hand, the aerobically purified N-truncated NifA protein bound to the nifB promoter, as demonstrated by an electrophoretic mobility shift assay, implying that DNA-binding activity is not strictly controlled by oxygen levels. Our data show that, while the N-truncated NifA is inactive in vivo under aerobic conditions, it still retains DNA-binding activity, suggesting that the oxidized form of NifA bound to DNA is not competent to activate transcription.

  12. Effect of the over-expression of PII and PZ proteins on the nitrogenase activity of Azospirillum brasilense.

    Science.gov (United States)

    Huergo, Luciano F; Filipaki, Angela; Chubatsu, Leda S; Yates, M Geoffrey; Steffens, Maria Berenice; Pedrosa, Fabio O; Souza, Emanuel M

    2005-12-01

    The Azospirillum brasilense PII and PZ proteins, encoded by the glnB and glnZ genes respectively, are intracellular transducers of nitrogen levels with distinct functions. The PII protein participates in nif regulation by controlling the activity of the transcriptional regulator NifA. PII is also involved in transducing the prevailing nitrogen levels to the Fe-protein ADP-ribosylation system. PZ regulates negatively ammonium transport and is involved in nitrogenase reactivation. To further investigate the role of PII and PZ in the regulation of nitrogen fixation, broad-host-range plasmids capable of over-expressing the glnB and glnZ genes under control of the ptac promoter were constructed and introduced into A. brasilense. The nitrogenase activity and nitrate-dependent growth was impaired in A. brasilense cells over-expressing the PII protein. Using immunoblot analysis we observed that the reduction of nitrogenase activity in cells over-expressing PII was due to partial ADP-ribosylation of the Fe-protein under derepressing conditions and a reduction in the amount of Fe-protein. These results support the hypothesis that the unmodified PII protein act as a signal to the DraT enzyme to ADP-ribosylate the Fe-protein in response to ammonium shock, and that it also inhibits nif gene expression. In cells over-expressing the PZ protein the nitrogenase reactivation after an ammonium shock was delayed indicating that the PZ protein is involved in regulation of DraG activity.

  13. Tryptophan, thiamine and indole-3-acetic acid exchange between Chlorella sorokiniana and the plant growth-promoting bacterium Azospirillum brasilense.

    Science.gov (United States)

    Palacios, Oskar A; Gomez-Anduro, Gracia; Bashan, Yoav; de-Bashan, Luz E

    2016-06-01

    During synthetic mutualistic interactions between the microalga Chlorella sorokiniana and the plant growth-promoting bacterium (PGPB) Azospirillum brasilense, mutual exchange of resources involved in producing and releasing the phytohormone indole-3-acetic acid (IAA) by the bacterium, using tryptophan and thiamine released by the microalga, were measured. Although increased activities of tryptophan synthase in C. sorokiniana and indole pyruvate decarboxylase (IPDC) in A. brasilense were observed, we could not detect tryptophan or IAA in the culture medium when both organisms were co-immobilized. This indicates that no extra tryptophan or IAA is produced, apart from the quantities required to sustain the interaction. Over-expression of the ipdC gene occurs at different incubation times: after 48 h, when A. brasilense was immobilized alone and grown in exudates of C. sorokiniana and at 96 h, when A. brasilense was co-immobilized with the microalga. When A. brasilense was cultured in exudates of C. sorokiniana, increased expression of the ipdC gene, corresponding increase in activity of IPDC encoded by the ipdC gene, and increase in IAA production were measured during the first 48 h of incubation. IAA production and release by A. brasilense was found only when tryptophan and thiamine were present in a synthetic growth medium (SGM). The absence of thiamine in SGM yielded no detectable IAA. In summary, this study demonstrates that C. sorokiniana can exude sufficient tryptophan and thiamine to allow IAA production by a PGPB during their interaction. Thiamine is essential for IAA production by A. brasilense and these three metabolites are part of a communication between the two microorganisms. PMID:27090758

  14. Main: SP8BFIBSP8BIB [PLACE

    Lifescience Database Archive (English)

    Full Text Available SP8BFIBSP8BIB S000184 16-Feb-2001 (last modified) seki One of SPBF binding site (SP...; SP8BF recognizes both SP8a and SP8b sequences; See also SP8BFIBSP8AIB (S000183); SP8BF activity is also fo

  15. Main: SP8BFIBSP8AIB [PLACE

    Lifescience Database Archive (English)

    Full Text Available SP8BFIBSP8AIB S000183 16-Feb-2001 (last modified) seki One of SPBF binding site (SP...o (I.b.); SP8BF recognizes both SP8a and SP8b sequences; See also SP8BFIBSP8BIB (S000184); SP8BF activity is

  16. Geminicoccus roseus gen. nov., sp. nov., an aerobic phototrophic Alphaproteobacterium isolated from a marine aquaculture biofilter.

    Science.gov (United States)

    Foesel, Bärbel U; Gössner, Anita S; Drake, Harold L; Schramm, Andreas

    2007-12-01

    A Gram-negative, strictly aerobic, diplococcoid bacterium (strain D2-3(T)) was isolated from the biofilter of a recirculating marine aquaculture system. Phylogenetic analysis of the 16S rRNA gene sequence of D2-3(T) indicated that the new organism occupied a novel lineage within the alpha-1 subclass of Proteobacteria and was related to the genera Rhodothalassium, Azospirillum, Craurococcus, Acidiphilium, and Tistrella. The highest sequence similarity (90.8%) of the 16S rRNA gene sequence of D2-3(T) was to that of Candidatus "Alysiosphaera europaea". D2-3(T) was mesophilic, heterotrophic, required sea salt, and had a pH optimum of 8.0. Growth in the presence of light resulted in the formation of pink colonies, a 25% increased cell yield, and a slightly increased growth rate. D2-3(T) contained carotenoids and low amounts of bacteriochlorophyll a. Membranes of D2-3(T) contained b-type cytochromes. The G+C content of the DNA was 60.3+/-0.1mol%. Phylogenetic, morphological, physiological, and biochemical analyses demonstrated that D2-3(T) represented a new aerobic phototrophic genus, for which the name Geminicoccus roseus gen. nov., sp. nov. is proposed for the type species (D2-3(T)=DSM 18922(T)=ATCC BAA-1445(T)). PMID:17643894

  17. Realocação de nitrogênio e de biomassa para os grãos, em trigo submetido a inoculação de Azospirillum Reallocation of nitrogen and biomass to the seeds in wheat inoculated with Azospirillum bacteria

    Directory of Open Access Journals (Sweden)

    AGOSTINHO DIRCEU DIDONET

    2000-02-01

    Full Text Available Estudou-se, em condições de campo, o efeito de inoculante turfoso em pó contendo bactérias do gênero Azospirillum no rendimento de grãos e na remobilização de N e de biomassa para os grãos de trigo (Triticum aestivum L., cultivar Embrapa 16. Usaram-se como inoculantes, a estirpe de Azospirillum brasilense 245 e o isolado 10 de Azospirillum lipoferum. Em cada tratamento de inoculação, e também sem inoculação, aplicaram-se diferentes doses de N em diferentes estádios de desenvolvimento das plantas, distribuídos em blocos ao acaso com parcelas subdivididas. Na antese e na maturação fisiológica, avaliaram-se o acúmulo de massa seca e N total nas diferentes partes da planta. Na colheita, além do rendimento de grãos, avaliaram-se também o índice de colheita para biomassa e para N, os principais componentes do rendimento e o teor de N total de grãos. Os resultados ainda preliminares evidenciaram que, mesmo não havendo efeito da inoculação no rendimento de grãos, houve um melhor alocamento de N e de biomassa para os grãos, resultando em maior massa de mil grãos e em menor quantidade de N restante na palha das plantas na maturação fisiológica. Esses efeitos resultaram de um menor número de espigas m-2, provavelmente devido à morte de afilhos, fator que determinou maior disponibilidade de N e de biomassa às espigas e grãos restantes.The effect of inoculating wheat (Triticum aestivum L. seeds, cultivar Embrapa 16, with powder peat inoculant containing Azospirillum bacteria on yield and remobilization of nitrogen and biomass was studied under field conditions. The strain of Azospirillum brasilense 245 and the isolate 10 of Azospirillum lipoferum were used as inoculants. Different rates of nitrogen were applied at varying stages of plant growth for each inoculated and non-inoculated treatment, distributed in blocks at random with split plots. The accumulation of dry matter and total nitrogen in plant parts was evaluated

  18. Identificação de isolados de Azospirillum amazonense associados a Brachiaria spp., em diferentes épocas e condições de cultivo e produção de fitormônio pela bactéria Identification of Azospirillum amazonense isolates associated to Brachiaria spp. at different stages and growth conditions, and bacterial plant hormone production

    OpenAIRE

    F. B. Reis Junior; Silva, M.F.; K. R. S. Teixeira; Urquiaga, S; V. M. Reis

    2004-01-01

    Existem evidências de que pastagens formadas por algumas espécies do gênero Brachiaria poderiam beneficiar-se com o processo de fixação biológica do nitrogênio atmosférico (FBN), garantindo a estas pastagens maior longevidade. Dentre as bactérias diazotróficas encontradas em associação com estas gramíneas forrageiras, destaca-se a espécie Azospirillum amazonense. Neste trabalho, objetivou-se verificar a influência da espécie de Brachiaria, manejo da pastagem e sazonalidade sobre as populações...

  19. Comparison of denitrification between Paracoccus sp. and Diaphorobacter sp.

    Science.gov (United States)

    Chakravarthy, Srinandan S; Pande, Samay; Kapoor, Ashish; Nerurkar, Anuradha S

    2011-09-01

    Denitrification was compared between Paracoccus sp. and Diaphorobacter sp. in this study, both of which were isolated from activated sludge of a denitrifying reactor. Denitrification of both isolates showed contrasting patterns, where Diaphorobacter sp. showed accumulation of nitrite in the medium while Paracoccus sp. showed no accumulation. The nitrate reduction rate was 1.5 times more than the nitrite reduction in Diaphorobacter sp., as analyzed by the resting state denitrification kinetics. Increasing the nitrate concentration in the medium increased the nitrite accumulation in Diaphorobacter sp., but not in Paracoccus sp., indicating a branched electron transfer during denitrification. Diaphorobacter sp. was unable to denitrify efficiently at high nitrate concentrations from 1 M, but Paracoccus sp. could denitrify even up to 2 M nitrate. Paracoccus sp. was found to be an efficient denitrifier with insignificant amounts of nitrite accumulation, and it could also denitrify high amounts of nitrate up to 2 M. Efficient denitrification without accumulation of intermediates like nitrite is desirable in the removal of high nitrates from wastewaters. Paracoccus sp. is shown to suffice this demand and could be a potential organism to remove high nitrates effectively. PMID:21509603

  20. Accumulation fatty acids of in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoA carboxylase, temperature, and co-immobilization with Azospirillum brasilense

    Science.gov (United States)

    Leyva, Luis A.; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E.

    2014-10-01

    The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae.

  1. Accumulation of fatty acids in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoAcarboxylase, temperature, and co-immobilization with Azospirillum brasilense [corrected].

    Science.gov (United States)

    Leyva, Luis A; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E

    2014-10-01

    The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae.

  2. EVALUACIÓN DE CEPAS NATIVAS DEL GÉNERO Azospirillum Y SU INTERACCIÓN CON EL CULTIVO DEL ARROZ

    Directory of Open Access Journals (Sweden)

    Mabel Pazos

    2001-01-01

    Full Text Available Catorce cepas nativas pertenecientes a la especie Azospirillum brasilense se caracterizaron en cuanto a su ca- pacidad de fijar el nitrógeno atmosférico. Se estudió su efecto en el cultivo del arroz (Oryza sativa, mediante el modelo Microcosmos, realizando determinaciones de la altura de las plantas inoculadas, masa fresca de la raíz y el contenido de fenoles libres y la cuantificación de proteínas en las hojas. Se observó en todos los casos un efecto positivo por la inocula- ción con estas rizobacterias, donde se destaca la cepa R5(15 con los mayores incrementos en los indicadores estudiados.

  3. Assessment of N2 fixing efficiency of Beijerinckia indica and Azospirillum brasilense in Sorghum (Sorghum bicolor (L.) moench) using 15N tracer

    International Nuclear Information System (INIS)

    For studying the benefits of inoculation of N2 fixing diazotrophs in the root zone of sorghum crop, a pot culture was conducted on neutral red sandy loam soil with sorghum cv. CO26, using 15N tracer. At the end of 45 days duration after sowing, Beijerinckia indica inoculation contributed 56.9 per cent N derived from N2 fixation, out of total N concentration in whole drymatter of sorghum plant. It proved to be the efficient N2 fixer by contributing N from N2 fixation to the tune of 17.6 Kg-1. Accumulation of N derived from N2 fixation from B. indica was primarily in leaf blade (50.0%) followed by stem (31.8%), leaf sheath (14.0%) and root (4.2%). Inoculation of Azospirillum brasllense accelerated uptake of N from soil and fertilizer N sources compared to B. indica and hence registered low N fixation. (author)

  4. TECNOLOGÍA DE PRODUCCIÓN DE INOCULANTES DE Azospirillum Y FACTIBILIDAD ECONÓMICA DE SU APLICACIÓN AGRÍCOLA EN CULTIVOS SELECCIONADOS

    Directory of Open Access Journals (Sweden)

    J. Villar

    2005-01-01

    Full Text Available El desarrollo de inoculantes bacterianos de uso agrícola puede contribuir a la disminución del empleo de fertilizantes químicos y favorecer el medio ambiente. Sin embargo, su aplicación debe resultar económica para los productores, sin detrimento de los rendimientos agrícolas tradicionales. En el presente trabajo se estiman los indicadores económicos de una planta industrial, a partir de una nueva tecnología que emplea turba y cachaza como soporte, para la obtención de dos tipos de inoculantes sólidos de Azospirillum: polvo húmedo para impregnación de semillas y polvo humedecible para aspersión en campo, y se analiza la factibilidad económica de la aplicación de estos inoculantes en los cultivos de caña de azúcar y arroz.

  5. Uso del biofertilizante Azospirillum como fuente alternativa para la fertilización nitrogenada de la caña de azúcar

    OpenAIRE

    Everaldo Becerra-De Armas; Ilia Lugo-Ruiz; Rafael Más-Martínez; Emma Pineda-Ruiz; Yudith Viñas-Quintero

    2014-01-01

    El presente trabajo se desarrolló sobre un suelo Pardo Sialítico Típico con el objetivo de validar la efectividad del biofertilizante Azospirillum, Cepa 8 INICA, con una concentración 109 UFC/mL en áreas cañeras de producción. Se utilizaron dos métodos de aplicación: asperjado con arrope y enterrado. Se empleó la variedad C86-12, cepa R1. Los parámetros altura, diámetro, conteo de tallos y hojas activas fueron evaluados a los 3 meses de edad. Los datos de rendimiento se obtuvieron a partir de...

  6. Detecção de Azospirillum amazonense em raízes e rizosfera de orchidaceae e de outras famílias vegetais

    Directory of Open Access Journals (Sweden)

    A. Lange

    2002-06-01

    Full Text Available Azospirillum amazonense é uma bactéria fixadora de N2 atmosférico de ampla ocorrência, principalmente em associações radiculares com gramíneas e palmeiras. Para verificar sua presença em outras espécies vegetais, ainda não estudadas, e a eficiência de meios para sua detecção, foram testados os meios Fam e LGI para contagens em solo rizosférico ou em culturas de enriquecimento com solo rizosférico, ecto e endorrizosfera. A. amazonense foi detectada no solo rizosférico, ecto e endorrizosfera de várias espécies de monocotiledôneas, incluindo Orchidaceae e dicotiledôneas, sendo o meio Fam mais eficiente para sua detecção

  7. Elemental composition of strawberry plants inoculated with the plant growth-promoting bacterium Azospirillum brasilense REC3, assessed with scanning electron microscopy and energy dispersive X-ray analysis.

    Science.gov (United States)

    Guerrero-Molina, M F; Lovaisa, N C; Salazar, S M; Díaz-Ricci, J C; Pedraza, R O

    2014-07-01

    The elemental composition of strawberry plants (Fragaria ananassa cv. Macarena) inoculated with the plant growth-promoting bacterium Azospirillum brasilense REC3, and non-inoculated controls, was studied using scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analysis. This allowed simultaneous semi-quantification of different elements in a small, solid sample. Plants were inoculated and grown hydroponically in 50% or 100% Hoagland solution, corresponding to limited or optimum nutrient medium, respectively. Bacteria-inoculated plants increased the growth index 45% and 80% compared to controls when grown in 100% and 50% Hoagland solution, respectively. Thus, inoculation with A. brasilense REC3 in a nutrient-limited medium had the strongest effect in terms of increasing both shoot and root biomass and growth index, as already described for Azospirillum inoculated into nutrient-poor soils. SEM-EDS spectra and maps showed the elemental composition and relative distribution of nutrients in strawberry tissues. Leaves contained C, O, N, Na, P, K, Ca and Cu, while roots also had Si and Cl. The organic fraction (C, O and N) accounted for over 96.3% of the total chemical composition; of the mineral fraction, Na had higher accumulation in both leaves and roots. Azospirillum-inoculated and control plants had similar elemental quantities; however, in bacteria-inoculated roots, P was significantly increased (34.33%), which constitutes a major benefit for plant nutrition, while Cu content decreased (35.16%).

  8. Control of Branchionus sp. and Amoeba sp. in cultures of Arthrospira sp. Control de Branchionus sp. y Amoeba sp. en cultivos de Arthrospira sp.

    Directory of Open Access Journals (Sweden)

    Carlos Méndez

    2012-09-01

    Full Text Available Cultivation of cyanobacterium Arthrospira sp. has been developed in many countries for the production of proteins, pigments and other compounds. Outdoor mass cultures are often affected by biological contamination, drastically reducing productivity as far as bringing death. This study evaluates the control of Branchionus sp. and Amoeba sp. with two chemical compounds: urea (U and ammonium bicarbonate (AB, in laboratory conditions and outdoor mass culture of Arthrospira sp. The lethal concentration 100 (LC100 at 24 h for Branchionus sp. and Amoeba sp. determined was of 60-80 mg L-1 (U and 100-150 mg L-1 (AB. The average effective inhibition concentration for 50% of the population (IC50 in Arthrospira sp., after 72 h, was 80 mg L-1 (U and 150 mg L-1 (AB. The application of doses of 60 mg L-1 (U or 100 mg L-1 (AB in the outdoor mass culture of this contaminated microalga, completely inhibited grazing and did not affect the growth of Arthrospira sp. but rather promoted rapid recovery of algal density at levels prior to infestation. These compounds provided an economical and effective control of predators in cultures of Arthrospira sp.El cultivo de la cianobacteria Arthrospira sp. ha sido desarrollado en muchos países para la obtención de proteínas, pigmentos y otros compuestos. Cultivo que a nivel industrial se ve afectado frecuentemente por contaminación biológica, reduciendo drásticamente la productividad hasta causar la muerte. Este estudio evalúa el control de Branchionus sp. y de Amoeba sp. con dos compuestos químicos, la urea (U y bicarbonato de amonio (AB en cultivos de Arthrospira sp. La concentración letal 100 (LC100 determinada a las 24 h para Branchionus sp. y Amoeba sp. fue de 60-80 mg L-1 (U y 100-150 mg L-1 (AB. La concentración media de inhibición efectiva, después de 72 h, para el 50% de la población (IC50 en Arthrospira fue de 80 mg L-1 (U y 150 mg L-1 (AB. La aplicación de dosis de 60 mg L-1 (U ó 100 mg L-1 (AB en

  9. Inoculação de Azospirillum amazonense em dois genótipos de milho sob diferentes regimes de nitrogênio Inoculation of Azospirillum amazonense in two maize genotypes under different N treatments

    Directory of Open Access Journals (Sweden)

    Fábio Bueno dos Reis Junior

    2008-06-01

    Full Text Available A adaptabilidade de genótipos de milho a ambientes onde os nutrientes não estejam prontamente disponíveis pode ser relacionada com a adaptação à predominância, nos solos, das formas de N nítrica e amoniacal e à associação com microrganismos benéficos como as bactérias diazotróficas e, ou, promotoras de crescimento de plantas. O objetivo deste trabalho foi verificar o comportamento de dois híbridos intervarietais de milho sob diferentes doses e formas de N, assim como o efeito da inoculação com Azospirillum amazonense, em um ensaio em casa de vegetação, utilizando vasos preenchidos com vermiculita e solução nutritiva de Hoagland como fonte de nutrientes. O delineamento experimental foi de blocos ao acaso em esquema fatorial, constituindo os tratamentos em: dois híbridos intervarietais, H1 (Carioca x Eldorado e H2 (Palha Roxa ES x Sol da Manhã; plantas inoculadas ou não inoculadas com A. amazonense, e três regimes de N, conforme doses e proporções seguintes: 126 mg semana-1 de N (75 % NH4+ : 25 % NO3-; 126 mg semana-1 de N (25 % NH4+ : 75 % NO3-, e 12,6 mg semana-1 de N (50 % NH4+ : 50 % NO3-. Vinte e cinco dias após o plantio, as plantas foram separadas em raiz e parte aérea para determinação da matéria seca, conteúdos totais de N e P, atividade das enzimas nitrato redutase e glutamina sintetase e açúcares solúveis totais. O híbrido H1, mais eficiente em avaliações preliminares em campo, produziu mais matéria seca e apresentou maior eficiência na utilização de N e P. Plantas que receberam a maior dose de N, independentemente do predomínio da forma nítrica ou amoniacal, apresentaram maior acúmulo de N (nas raízes e parte aérea e P (na parte aérea e maior índice de utilização de P. Com o predomínio da forma amoniacal, observou-se incremento na produção de matéria seca da parte aérea e na atividade da glutamina sintetase, bem como decréscimo na concentração de açúcares solúveis totais

  10. SP-100 Test Site

    International Nuclear Information System (INIS)

    Preparatory activities are well under way at Hanford to convert the 309 Containment Building and its associated service wing to a 2.5 MWt nuclear test facility for the SP-100 Ground Engineering System (GES) test. Preliminary design is complete, encompassing facility modifications, a secondary heat transport system, a large vacuum system to enclose the high temperature reactor, a test assembly cell and handling system, control and data processing systems, and safety and auxiliary systems. The design makes extensive use of existing equipment to minimize technical risk and cost. Refurbishment of this equipment is 75% complete. The facility has been cleared of obstructing equipment from its earlier reactor test. Current activities are focusing on definitive design and preparation of the Preliminary Safety Analysis Report (PSAR) aimed at procurement and construction approvals and schedules to achieve reactor criticality by January 1992. 6 refs

  11. Evaluación de la eficiencia agronómica de Azospirillum brasilense en la cultura del trigo y los efectos en la calidad de la harina Avaliação da eficiência agronômica de Azospirillum brasilense na cultura do trigo e os efeitos na qualidade de farinha

    Directory of Open Access Journals (Sweden)

    Marcelo Cruz Mendes

    2012-06-01

    Full Text Available

    El objetivo de este estudio fue evaluar la eficacia de la inoculación de la bacteria Azospirillum brasilense sobre parámetros agronómicos del cultivo de trigo en los, donde se utilizó la dosis recomendada de bacterias y tres veces esta dosis, en comparación con dos niveles de nitrógeno abonado aplicado en cobertura. El experimento se llevó a cabo en el campo experimental de la Facultad de Agronomía de la Universidade Estadual do Centro Oeste, en Guarapuava-PR/Brasil. El diseño experimental fue bloques al azar con cinco repeticiones, con un total de 35 parcelas (7 tratamientos x 5 repeticiones. Las parcelas se consistieron de nueve filas (5,0 m de largo x 0,17 m entre filas, con una superficie total de 7,65 m2 y área útil compuesta por las dos filas centrales. Los parámetros de la planta obtenidos muestran que el uso de bacterias Azospirillum brasilense no causó ninguna diferencia estadística en la productividad en comparación con los demás tratamientos. Además, los parámetros de calidad de harina evaluados no difirieran estadísticamente, lo que indica que los tratamientos con y sin reducción de nitrógeno y con y sin el uso de Azospirillum brasilense, no fueron capaces de reducir la sedimentación, proteína y falling number. De este modo, se pude inferir que la bacteria tiene una eficiencia agronómica en la aplicación como tratamiento de semillas con el objetivo principalmente a la reducción de la aplicación de nitrógeno como abono de cobertura.

    O objetivo do trabalho foi o de avaliar a eficiência da inoculação da bactéria Azospirillum brasilense sobre os parâmetros agronômicos da cultura do trigo, onde utilizou-se a dosagem recomendada da bactéria e três vezes essa dosagem, frente a dois níveis de adubação nitrogenada em cobertura. O experimento foi conduzido no campo experimental do Departamento de Agronomia da Universidade

  12. In Azospirillum brasilense, mutations in flmA or flmB genes affect polar flagellum assembly, surface polysaccharides, and attachment to maize roots.

    Science.gov (United States)

    Rossi, Fernando Ariel; Medeot, Daniela Beatriz; Liaudat, Juan Pablo; Pistorio, Mariano; Jofré, Edgardo

    2016-09-01

    Azospirillum brasilense is a soil bacterium capable of promoting plant growth. Several surface components were previously reported to be involved in the attachment of A. brasilense to root plants. Among these components are the exopolysaccharide (EPS), lipopolysaccharide (LPS) and the polar flagellum. Flagellin from polar flagellum is glycosylated and it was suggested that genes involved in such a posttranslational modification are the same ones involved in the biosynthesis of sugars present in the O-antigen of the LPS. In this work, we report on the characterization of two homologs present in A. brasilense Cd, to the well characterized flagellin modification genes, flmA and flmB, from Aeromonas caviae. We show that mutations in either flmA or flmB genes of A. brasilense resulted in non-motile cells due to alterations in the polar flagellum assembly. Moreover, these mutations also affected the capability of A. brasilense cells to adsorb to maize roots and to produce LPS and EPS. By generating a mutant containing the polar flagellum affected in their rotation, we show the importance of the bacterial motility for the early colonization of maize roots.

  13. Positive effect of reduced aeration rate on growth and stereospecificity of DL-malic acid consumption by Azospirillum brasilense: improving the shelf life of a liquid inoculant formulation.

    Science.gov (United States)

    Carrasco-Espinosa, Karen; García-Cabrera, Ramsés I; Bedoya-López, Andrea; Trujillo-Roldán, Mauricio A; Valdez-Cruz, Norma A

    2015-02-10

    Azospirillum brasilense has significance as a growth promoter in plants of commercial interest. Two industrial native strains (Start and Calf), used as a part of an inoculant formulation in Mexico during the last 15 years, were incubated in laboratory-scale pneumatic bioreactors at different aeration rates. In both strains, the positive effect of decreased aeration was observed. At the lowest (0.1 vvm, air volume/liquid volume×minute), the highest biomass were obtained for Calf (7.8 × 10(10)CFU/ml), and Start (2.9 × 10(9)CFU/ml). These were higher in one magnitude order compared to cultures carried out at 0.5 vvm, and two compared to those at 1.0 vvm. At lower aeration, both stereoisomeric forms of malic acid were consumed, but at higher aeration, just L-malate was consumed. A reduction in aeration allows an increase of the shelf life and the microorganism saved higher concentrations of polyhydroxybutyrate. The selected fermentation conditions are closely related to those prevalent in large-scale bioreactors and offer the possibility of achieving high biomass titles with high shelf life at a reduced costs, due to the complete use of a carbon source at low aeration of a low cost raw material as DL-malic acid mixture in comparison with the L-malic acid stereoisomer.

  14. Characterization of cell surface and extracellular matrix remodeling of Azospirillum brasilense chemotaxis-like 1 signal transduction pathway mutants by atomic force microscopy.

    Science.gov (United States)

    Edwards, Amanda Nicole; Siuti, Piro; Bible, Amber N; Alexandre, Gladys; Retterer, Scott T; Doktycz, Mitchel J; Morrell-Falvey, Jennifer L

    2011-01-01

    To compete in complex microbial communities, bacteria must sense environmental changes and adjust cellular functions for optimal growth. Chemotaxis-like signal transduction pathways are implicated in the regulation of multiple behaviors in response to changes in the environment, including motility patterns, exopolysaccharide production, and cell-to-cell interactions. In Azospirillum brasilense, cell surface properties, including exopolysaccharide production, are thought to play a direct role in promoting flocculation. Recently, the Che1 chemotaxis-like pathway from A. brasilense was shown to modulate flocculation, suggesting an associated modulation of cell surface properties. Using atomic force microscopy, distinct changes in the surface morphology of flocculating A. brasilense Che1 mutant strains were detected. Whereas the wild-type strain produces a smooth mucosal extracellular matrix after 24 h, the flocculating Che1 mutant strains produce distinctive extracellular fibril structures. Further analyses using flocculation inhibition, lectin-binding assays, and comparison of lipopolysaccharides profiles suggest that the extracellular matrix differs between the cheA1 and the cheY1 mutants, despite an apparent similarity in the macroscopic floc structures. Collectively, these data indicate that disruption of the Che1 pathway is correlated with distinctive changes in the extracellular matrix, which likely result from changes in surface polysaccharides structure and/or composition.

  15. Characterization of Cell Surface and EPS Remodeling of Azospirillum brasilense Chemotaxis-like 1 Signal Transduction Pathway mutants by Atomic Force Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Billings, Amanda N [ORNL; Siuti, Piro [ORNL; Bible, Amber [University of Tennessee, Knoxville (UTK); Alexandre, Gladys [University of Tennessee, Knoxville (UTK); Retterer, Scott T [ORNL; Doktycz, Mitchel John [ORNL; Morrell-Falvey, Jennifer L [ORNL

    2011-01-01

    To compete in complex microbial communities, bacteria must quickly sense environmental changes and adjust cellular functions for optimal growth. Chemotaxis-like signal transduction pathways are implicated in the modulation of multiple cellular responses, including motility, EPS production, and cell-to-cell interactions. Recently, the Che1 chemotaxis-like pathway from Azospirillum brasilense was shown to modulate flocculation. In A. brasilense, cell surface properties, including EPS production, are thought to play a direct role in promoting flocculation. Using atomic force microscopy (AFM), we have detected distinct changes in the surface morphology of flocculating A. brasilense Che1 mutant strains that are absent in the wild type strain. Whereas the wild type strain produces a smooth mucosal extracellular matrix, the flocculating Che1 mutant strains produce distinctive extracellular fibril structures. Further analyses using flocculation inhibition and lectin-binding assays suggest that the composition of EPS components in the extracellular matrix differs between the cheA1 and cheY1 mutants, despite an apparent similarity in the macroscopic floc structures. Collectively, these data indicate that mutations in the Che1 pathway that result in increased flocculation are correlated with distinctive changes in the extracellular matrix structure produced by the mutants, including likely changes in the EPS structure and/or composition.

  16. Tn5-mutagenesis and identification of atr operon and trpE gene responsible for indole-3-acetic acid synthesis in Azospirillum brasilense Yu62

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To bring more information about synthesis of indole-3-acetic acid (IAA) from Azospirillum brasilense, a Tn5-insertion library of A. brasilense Yu62 was constructed and subjected to screening for IAA producing mutants. Two mutants with decreased IAA levels, named as A3 and A24, were isolated. The sequence analysis of loci tagged showed that the Tn5-1063a was located in the atrA gene encoding GntR family transcriptional regulator and trpE gene encoding component I of anthranilate synthase respectively. At the same time, atrB encoding phosphotransferase and atrC encoding aminotransferase were cloned downstream the atrA gene and atrA,atrB and atrC were clustered in an operon. Mutagenesis and complementation studies showed that atrA and atrC were involved in IAA synthesis. IAA levels of trpE mutant and wild-type strain could be improved by adding anthranilate into the medium.

  17. Alternative mechanism for the evaluation of indole-3-acetic acid (IAA) production by Azospirillum brasilense strains and its effects on the germination and growth of maize seedlings.

    Science.gov (United States)

    Masciarelli, Oscar; Urbani, Lucia; Reinoso, Herminda; Luna, Virginia

    2013-10-01

    We evaluated the production of indole-3-acetic acid (IAA) by Azospirillum brasilense strains in vitro (cell culture supernatants) and in vivo (stems and roots of maize seedlings) to clarify the role of this phytohormone as a signaling and effector molecule in the symbiotic interaction between maize and A. brasilense. The three strains all showed IAA production when cultured in NFb medium supplemented with 100 μg/ml L-tryptophan. The level of IAA production was 41.5 μg/ml for Yu62, 12.9 μg/ml for Az39, and 0.15 μg/ml for ipdC-. The release of IAA into culture medium by the bacteria appeared to be the main activator of the early growth promotion observed in the inoculated maize seedlings. The application of supernatants with different IAA contents caused significant differences in the seedling growth. This observation provides the basis for novel technological tools for effective quality control procedures on inoculants. The approach described can be incorporated into different inoculation methods, including line sowing, downspout, and foliar techniques, and increase the sustainability of symbiotic plant-bacteria systems.

  18. Scale-up from shake flasks to pilot-scale production of the plant growth-promoting bacterium Azospirillum brasilense for preparing a liquid inoculant formulation.

    Science.gov (United States)

    Trujillo-Roldán, Mauricio A; Valdez-Cruz, Norma A; Gonzalez-Monterrubio, César F; Acevedo-Sánchez, Eduardo V; Martínez-Salinas, Carlos; García-Cabrera, Ramsés I; Gamboa-Suasnavart, Ramsés A; Marín-Palacio, Luz D; Villegas, Jesús; Blancas-Cabrera, Abel

    2013-11-01

    Azospirillum brasilense has industrial significance as a growth promoter in plants of commercial interest. However, there is no report in the literature disclosing a liquid product produced in pilot-scale bioreactors and is able to be stored at room temperature for more than 2 years. The aim of this work was to scale up a process from a shake flask to a 10-L lab-scale and 1,000-L pilot-scale bioreactor for the production of plant growth-promoting bacterium A. brasilense for a liquid inoculant formulation. Furthermore, this work aimed to determine the shelf life of the liquid formulation stored at room temperature and to increase maize crops yield in greenhouses. Under a constant oxygen mass transfer coefficient (K L a), a fermentation process was successfully scaled up from shake flasks to 10- and 1,000-L bioreactors. A concentration ranging from 3.5 to 7.5 × 10(8) CFU/mL was obtained in shake flasks and bioreactors, and after 2 years stored at room temperature, the liquid formulation showed one order of magnitude decrease. Applications of the cultured bacteria in maize yields resulted in increases of up to 95 % in corncobs and 70 % in aboveground biomass.

  19. Accumulation of intra-cellular polyphosphate in Chlorella vulgaris cells is related to indole-3-acetic acid produced by Azospirillum brasilense.

    Science.gov (United States)

    Meza, Beatriz; de-Bashan, Luz E; Hernandez, Juan-Pablo; Bashan, Yoav

    2015-06-01

    Accumulation of intra-cellular phosphate, as polyphosphate, was measured when the microalga Chlorella vulgaris was immobilized in alginate with either of two wild-type strains of the microalgae growth-promoting bacterium Azospirillum brasilense or their corresponding IAA-attenuated mutants. Wild type strains of A. brasilense induced higher amounts of intra-cellular phosphate in Chlorella than their respective mutants. Calculations comparing intra-cellular phosphate accumulation by culture or net accumulation by the cell and the amount of IAA that was produced by each of these strains revealed that higher IAA was linked to higher accumulations of intra-cellular phosphate. Application of four levels of exogenous IAA reported for A. brasilense and their IAA-attenuated mutants to cultures of C. vulgaris enhanced accumulation of intra-cellular phosphate; the higher the content of IAA per culture or per single cell, the higher was the amount of accumulated phosphate. When an IAA-attenuated mutant was complemented with exogenous IAA, accumulation of intra-cellular phosphate at the culture level was even higher than phosphate accumulation with the respective wild type strains. When calculating the net accumulation of intra-cellular phosphate in the complementation experiment, net intra-cellular phosphate induced by the IAA-attenuated mutant was completely restored and was similar to the wild strains. We propose that IAA produced by A. brasilense is linked to polyphosphate accumulation in C. vulgaris.

  20. Characterization of cell surface and extracellular matrix remodeling of Azospirillum brasilense chemotaxis-like 1 signal transduction pathway mutants by atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Doktycz, Mitchel John [ORNL; Morrell-Falvey, Jennifer L [ORNL

    2011-01-01

    To compete in complex microbial communities, bacteria must sense environmental changes and adjust cellular functions for optimal growth. Chemotaxis-like signal transduction pathways are implicated in the regulation of multiple behaviors in response to changes in the environment, including motility patterns, exopolysaccharide production, and cell-to-cell interactions. In Azospirillum brasilense, cell surface properties, including exopolysaccharide production, are thought to play a direct role in promoting flocculation. Recently, the Che1 chemotaxis-like pathway from A. brasilense was shown to modulate flocculation, suggesting an associated modulation of cell surface properties. Using atomic force microscopy, distinct changes in the surface morphology of flocculating A. brasilense Che1 mutant strains were detected. Whereas the wild-type strain produces a smooth mucosal extracellular matrix after 24 h, the flocculating Che1 mutant strains produce distinctive extracellular fibril structures. Further analyses using flocculation inhibition, lectin-binding assays, and comparison of lipopolysaccharides profiles suggest that the extracellular matrix differs between the cheA1 and the cheY1 mutants, despite an apparent similarity in the macroscopic floc structures. Collectively, these data indicate that disruption of the Che1 pathway is correlated with distinctive changes in the extracellular matrix, which likely result from changes in surface polysaccharides structure and/or composition.

  1. Effect of ATP and 2-oxoglutarate on the in vitro interaction between the NifA GAF domain and the GlnB protein of Azospirillum brasilense

    Energy Technology Data Exchange (ETDEWEB)

    Sotomaior, P.; Araújo, L.M.; Nishikawa, C.Y.; Huergo, L.F.; Monteiro, R.A.; Pedrosa, F.O.; Chubatsu, L.S.; Souza, E.M. [Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, PR (Brazil)

    2012-09-21

    Azospirillum brasilense is a diazotroph that associates with important agricultural crops and thus has potential to be a nitrogen biofertilizer. The A. brasilense transcription regulator NifA, which seems to be constitutively expressed, activates the transcription of nitrogen fixation genes. It has been suggested that the nitrogen status-signaling protein GlnB regulates NifA activity by direct interaction with the NifA N-terminal GAF domain, preventing the inhibitory effect of this domain under conditions of nitrogen fixation. In the present study, we show that an N-terminal truncated form of NifA no longer required GlnB for activity and lost regulation by ammonium. On the other hand, in trans co-expression of the N-terminal GAF domain inhibited the N-truncated protein in response to fixed nitrogen levels. We also used pull-down assays to show in vitro interaction between the purified N-terminal GAF domain of NifA and the GlnB protein. The results showed that A. brasilense GlnB interacts directly with the NifA N-terminal domain and this interaction is dependent on the presence of ATP and 2-oxoglutarate.

  2. Effect of ATP and 2-oxoglutarate on the in vitro interaction between the NifA GAF domain and the GlnB protein of Azospirillum brasilense

    Directory of Open Access Journals (Sweden)

    P. Sotomaior

    2012-12-01

    Full Text Available Azospirillum brasilense is a diazotroph that associates with important agricultural crops and thus has potential to be a nitrogen biofertilizer. The A. brasilense transcription regulator NifA, which seems to be constitutively expressed, activates the transcription of nitrogen fixation genes. It has been suggested that the nitrogen status-signaling protein GlnB regulates NifA activity by direct interaction with the NifA N-terminal GAF domain, preventing the inhibitory effect of this domain under conditions of nitrogen fixation. In the present study, we show that an N-terminal truncated form of NifA no longer required GlnB for activity and lost regulation by ammonium. On the other hand, in trans co-expression of the N-terminal GAF domain inhibited the N-truncated protein in response to fixed nitrogen levels. We also used pull-down assays to show in vitro interaction between the purified N-terminal GAF domain of NifA and the GlnB protein. The results showed that A. brasilense GlnB interacts directly with the NifA N-terminal domain and this interaction is dependent on the presence of ATP and 2-oxoglutarate.

  3. Effect of ATP and 2-oxoglutarate on the in vitro interaction between the NifA GAF domain and the GlnB protein of Azospirillum brasilense.

    Science.gov (United States)

    Sotomaior, P; Araújo, L M; Nishikawa, C Y; Huergo, L F; Monteiro, R A; Pedrosa, F O; Chubatsu, L S; Souza, E M

    2012-12-01

    Azospirillum brasilense is a diazotroph that associates with important agricultural crops and thus has potential to be a nitrogen biofertilizer. The A. brasilense transcription regulator NifA, which seems to be constitutively expressed, activates the transcription of nitrogen fixation genes. It has been suggested that the nitrogen status-signaling protein GlnB regulates NifA activity by direct interaction with the NifA N-terminal GAF domain, preventing the inhibitory effect of this domain under conditions of nitrogen fixation. In the present study, we show that an N-terminal truncated form of NifA no longer required GlnB for activity and lost regulation by ammonium. On the other hand, in trans co-expression of the N-terminal GAF domain inhibited the N-truncated protein in response to fixed nitrogen levels. We also used pull-down assays to show in vitro interaction between the purified N-terminal GAF domain of NifA and the GlnB protein. The results showed that A. brasilense GlnB interacts directly with the NifA N-terminal domain and this interaction is dependent on the presence of ATP and 2-oxoglutarate.

  4. Purification of the major outer membrane protein of Azospirillum brasilense, its affinity to plant roots, and its involvement in cell aggregation.

    Science.gov (United States)

    Burdman, S; Dulguerova, G; Okon, Y; Jurkevitch, E

    2001-04-01

    The major outer membrane protein (MOMP) of the nitrogen-fixing rhizobacterium Azospirillum brasilense strain Cd was purified and isolated by gel filtration, and antiserum against this protein was obtained. A screening of the binding of outer membrane proteins (OMPs) of A. brasilense to membrane-immobilized root extracts of various plant species revealed different affinities for the MOMP, with a stronger adhesion to extracts of cereals in comparison with legumes and tomatoes. Moreover, this protein was shown to bind to roots of different cereal seedlings in an in vitro adhesion assay. Incubation of A. brasilense cells with MOMP-antiserum led to fast agglutination, indicating that the MOMP is a surface-exposed protein. Cells incubated with Fab fragments obtained from purified MOMP-antiserum immunoglobulin G exhibited significant inhibition of bacterial aggregation as compared with controls. Bacteria preincubated with Fab fragments showed weaker adhesion to corn roots in comparison to controls without Fab fragments. These findings suggest that the A. brasilense MOMP acts as an adhesin involved in root adsorption and cell aggregation of this bacterium.

  5. Cultivation factors and population size control the uptake of nitrogen by the microalgae Chlorella vulgaris when interacting with the microalgae growth-promoting bacterium Azospirillum brasilense.

    Science.gov (United States)

    de-Bashan, Luz E; Antoun, Hani; Bashan, Yoav

    2005-10-01

    Growth of and the capacity to take up nitrogen in the freshwater microalgae Chlorella vulgaris were studied while varying the concentrations of ammonium and nitrate, the pH and the source of carbon in a synthetic wastewater growth medium when co-immobilized in alginate beads with the microalgae growth-promoting bacterium Azospirillum brasilense. Analyses of 29 independent experiments showed that co-immobilization of the microalgae with A. brasilense could result in two independent phenomena directly affected by cultivation factors, such as nitrogen species, pH and presence of a carbon source. First, growth of the microalgal population increased without an increase in the capacity of the single cells to take up nitrogen, or second, the capacity of cells to take up nitrogen increased without an increase of the total microalgal population. These phenomena were dependent on the population density of the microalgae, which was in turn affected by cultivation factors. This supports the conclusion that the size of the microalgal population controls the uptake of nitrogen in C. vulgaris cells - the higher the population (regardless the experimental parameters), the less nitrogen each cell takes up.

  6. ADP-ribosylation of dinitrogenase reductase in Azospirillum brasilense is regulated by AmtB-dependent membrane sequestration of DraG.

    Science.gov (United States)

    Huergo, Luciano F; Souza, Emanuel M; Araujo, Mariana S; Pedrosa, Fábio O; Chubatsu, Leda S; Steffens, Maria B R; Merrick, Mike

    2006-01-01

    Nitrogen fixation in some diazotrophic bacteria is regulated by mono-ADP-ribosylation of dinitrogenase reductase (NifH) that occurs in response to addition of ammonium to the extracellular medium. This process is mediated by dinitrogenase reductase ADP-ribosyltransferase (DraT) and reversed by dinitrogenase reductase glycohydrolase (DraG), but the means by which the activities of these enzymes are regulated are unknown. We have investigated the role of the P(II) proteins (GlnB and GlnZ), the ammonia channel protein AmtB and the cellular localization of DraG in the regulation of the NifH-modification process in Azospirillum brasilense. GlnB, GlnZ and DraG were all membrane-associated after an ammonium shock, and both this membrane sequestration and ADP-ribosylation of NifH were defective in an amtB mutant. We now propose a model in which membrane association of DraG after an ammonium shock creates a physical separation from its cytoplasmic substrate NifH thereby inhibiting ADP-ribosyl-removal. Our observations identify a novel role for an ammonia channel (Amt) protein in the regulation of bacterial nitrogen metabolism by mediating membrane sequestration of a protein other than a P(II) family member. They also suggest a model for control of ADP-ribosylation that is likely to be applicable to all diazotrophs that exhibit such post-translational regulation of nitrogenase.

  7. ROLE OF GLUTAMATE DEHYDROGENASE AND GLUTAMINE SYNTHETASE IN CHLORELLA VULGARIS DURING ASSIMILATION OF AMMONIUM WHEN JOINTLY IMMOBILIZED WITH THE MICROALGAE-GROWTH-PROMOTING BACTERIUM AZOSPIRILLUM BRASILENSE(1).

    Science.gov (United States)

    De-Bashan, Luz E; Magallon, Paola; Antoun, Hani; Bashan, Yoav

    2008-10-01

    Enzymatic activities of glutamate dehydrogenase (GDH) and glutamine synthetase (GS) participating in the nitrogen metabolism and related ammonium absorption were assayed after the microalga Chlorella vulgaris Beij. was jointly immobilized with the microalgae-growth-promoting bacterium Azospirillum brasilense. At initial concentrations of 3, 6, and 10 mg · L(-1)  NH4 (+) , joint immobilization enhances growth of C. vulgaris but does not affect ammonium absorption capacity of the microalga. However, at 8 mg · L(-1)  NH4 (+) , joint immobilization enhanced ammonium absorption by the microalga without affecting the growth of the microalgal population. Correlations between absorption of ammonium per cell and per culture showed direct (negative and positive) linear correlations between these parameters and microalga populations at 3, 6, and 10 mg · L(-1)  NH4 (+) , but not at 8 mg · L(-1)  NH4 (+) , where the highest absorption of ammonium occurred. In all cultures, immobilized and jointly immobilized, having the four initial ammonium concentrations, enzymatic activities of Chlorella are affected by A. brasilense. Regardless of the initial concentration of ammonium, GS activity in C. vulgaris was always higher when jointly immobilized and determined on a per-cell basis. When jointly immobilized, only at an initial concentration of 8 mg · L(-1)  NH4 (+) was GDH activity per cell higher.

  8. Bradysia sp. em morangueiro Bradysia sp. in strawberry

    Directory of Open Access Journals (Sweden)

    Bernadete Radin

    2009-04-01

    Full Text Available No trabalho, relatam-se os primeiros registros de Bradysia sp. (Insecta: Diptera: Sciaridae em morangueiro (Fragaria x ananassa Duch., cultivado no Município de Eldorado do Sul, RS. O cultivo foi realizado em sacolas com três metros de comprimento, preenchidas com substrato composto de casca de arroz e turfa, dispostas horizontalmente sobre bancadas de madeira, em ambiente protegido. A presença de Bradysia sp. foi observada na segunda quinzena de agosto de 2005. Neste trabalho, estão descritos os sintomas apresentados no morangueiro pela praga, prováveis conseqüências sobre o aparecimento de doenças e uma breve descrição morfológica da Bradysia sp., adulto e fase larval.This paper describes the first record of Bradysia sp. (Insecta; Diptera; Sciaridae in strawberry (Fragaria x ananassa, cultivated in the city of Eldorado do Sul, RS, Brazil. Strawberry was planted in plastic bags filled with a mixture of burnt rice hulls and peat and cultivated in a greenhouse. The presence of Bradysia sp was noticed in the second fortnight of August, 2005. The symptoms in strawberry and the probable consequences in terms of disease arising were described in the present study, as well as the morphological characterization of Bradysia sp. and its illustrations.

  9. Isolation and identification by 16s rrna sequence analysis of achromobacter, azospirillum and rhodococcus strains from the rhizosphere of maize and screening for the beneficial effect on plant growth

    International Nuclear Information System (INIS)

    The aim of the present study was to isolate and characterize plant growth promoting rhizobacteria from the rhizosphere of field-grown maize. Among the five bacterial isolates obtained in the present study, the isolates M1, M7 and ZN1 showed typical Azospirillum-like cell morphology, motility and high sequence similarity of 16S rDNA to the genus Azospirillum. The isolates M25 and M28 were identified on the bases of 16S rRNA sequence analysis as Achromobacter and Rhodococcus, respectively. All the five isolates obtained in the present study produced phytohormone IAA in pure culture but phosphate-solubilization activity was detected only in pure cultures of Achromobacter strain M25 and Rhodococcus strain M28. The isolates were tested as inoculants for maize seedlings grown in sterilized sand from which cotyledons were removed at an early growth stage to deprive the seedlings of internal nutrient source and harvested after 5 weeks. For comparison, seedlings with intact cotyledons were used as control. In addition inoculated plants were grown in non-sterilized soil in earthen pots and harvested at maturity. In both the short-term inoculation experiments carried out in sterilized sand as well as in long-term inoculation experiment in earthen pots all the inoculated strains improved plant growth compared to respective non-inoculated controls. However, unlike the seedlings with intact cotyledons, the pattern regarding the efficiency of growth promotion by inoculated strains (Azospirillum strains ZN1>M7>M1>Achromobacter strain M25>Rhodococcus strain M28) was the same in plants with detached cotyledons and the plants grown to maturity in non-sterilized soil. It can be concluded from the short-term experiments under controlled conditions that removal of cotyledons helps effective screening of bacterial inocula compared to seedlings with intact cotyledons. (author)

  10. SP-100 advanced technology program

    International Nuclear Information System (INIS)

    The goal of the triagency SP-100 Program is to develop long-lived, compact, lightweight, survivable nuclear reactor space power systems for application to the power range 50 kWe to 1 MWe. The successful development of these systems should enable or significantly enhance many of the future NASA civil and commercial missions. The NASA SP-100 Advanced Technology Program strongly augments the parallel SP-100 Ground Engineering System Development program and enhances the chances for success of the overall SP-100 program. The purpose of this paper is to discuss the key technical elements of the Advanced Technology Program and the progress made in the initial year and a half of the project

  11. Características agronômicas do trigo em função de Azospirillum brasilense, ácidos húmicos e nitrogênio em casa de vegetação

    OpenAIRE

    Luan F. O. S. Rodrigues; Vandeir F. Guimarães; Mônica B. da Silva; Artur S. Pinto Junior; Jeferson Klein; Andreia C. P. R. da Costa

    2014-01-01

    Objetivou-se, neste estudo, verificar o efeito do uso combinado de Azospirillum brasilense, ácidos húmicos e diferentes doses de nitrogênio nas características agronômicas do trigo. Os experimentos foram instalados no dia 21 de maio de 2011 e a colheita foi procedida no dia 13 de setembro de 2011. O delineamento experimental adotado foi o de blocos casualizados em esquema fatorial 4 x 4, com quatro repetições. O primeiro fator se refere à combinação da estirpe Ab-V5 de A. brasilense com os ác...

  12. En moderne spøgelseshistorie

    DEFF Research Database (Denmark)

    Simonsen, Karen-Margrethe

    2011-01-01

    Anmeldelse af César Airas "Spøgelserne". Anmeldelsen indkredser bla. spøgelsernes karakter i denne moderne, interkulturelle historie......Anmeldelse af César Airas "Spøgelserne". Anmeldelsen indkredser bla. spøgelsernes karakter i denne moderne, interkulturelle historie...

  13. Optimal spænding i kajakken

    DEFF Research Database (Denmark)

    Rossing, Niels Nygaard

    2012-01-01

    Artiklens overordnede fokus er, hvilken betydning den enkelte kajakroers spændingsniveau har for præstationen. Artiklen svarer på, hvad et spændingsniveau er, hvilke kilder der er til spænding, og sidst hvad man kan gøre for at finde sit optimale spændingsniveau....

  14. Fungi Association with Cedar’s Seeds and Fusarium sp. and Pestalotia sp. Pathogenicities Levantamento de Fungos em Sementes de Cedro e Avaliação da Patogenicidade de Fusarium sp. e Pestalotia sp.

    OpenAIRE

    Sílvia Cristina Benetti; Álvaro Figueredo dos Santos; Antonio Carlos de Souza Medeiros; David de Souza Jaccoud Filho

    2010-01-01

    This research had as main objectives the evaluation of cedar’s seeds seed-borne fungi and the Fusarium
    sp. and Pestalotia sp. pathogenicities. For the fungi detection Potato Dextrose and Agar medium and Blotter
    test methods were used. For the pathogenicity tests, isolates of Fusarium sp. and Pestalotia sp. were used. The following fungi were observed: Pestalotia sp., Fusarium sp., Phomopsis sp., Colletotrichum sp., Macrophomina sp. and Cladosporium sp. The fungi...

  15. Penicillium araracuarense sp. nov., Penicillium elleniae sp. nov., Penicillium penarojense sp. nov., Penicillium vanderhammenii sp. nov. and Penicillium wotroi sp. nov., isolated from leaf litter

    DEFF Research Database (Denmark)

    Houbraken, Jos; López-Quintero, Carlos A.; Frisvad, Jens Christian;

    2011-01-01

    Several species of the genus Penicillium were isolated during a survey of the mycobiota of leaf litter and soil in Colombian Amazon forest. Five species, Penicillium penarojense sp. nov. (type strain CBS 113178T = IBT 23262T), Penicillium wotroi sp. nov. (type strain CBS 118171T = IBT 23253T......), Penicillium araracuarense sp. nov. (type strain CBS 113149T = IBT 23247T), Penicillium elleniae sp. nov. (type strain CBS 118135T = IBT 23229T) and Penicillium vanderhammenii sp. nov. (type strain CBS 126216T = IBT 23203T) are described here as novel species. Their taxonomic novelty was determined using...... a polyphasic approach, combining phenotypic, molecular (ITS and partial β-tubulin sequences) and extrolite data. Phylogenetic analyses showed that each novel species formed a unique clade for both loci analysed and that they were most closely related to Penicillium simplicissimum, Penicillium janthinellum...

  16. Inoculación con Azospirillum spp. en la Región Semiárida-Central de Argentina: factores que afectan la colonización rizosférica Inoculation with Azospirillum spp. in the semiarid-central region of Argentina: factors involved in rhizosphere colonization

    Directory of Open Access Journals (Sweden)

    Adriana Abril

    2006-07-01

    Full Text Available La efectividad de la inoculación con Azospirillum spp. en condiciones de campo a menudo es poco consistente. La colonización de la rizosfera por las bacterias del inoculante es un prerrequisito para el éxito de la inoculación. El objetivo de este trabajo fue evaluar el grado de colonización de raíces en 11 ensayos de campo con diferentes tratamientos (localidades, cepas, cultivos, cultivares, etc. en la Región semiárida central de la Argentina. Todos los ensayos se realizaron con similar diseño experimental y metodología de análisis para permitir su comparación. El grado de colonización mostró alta variabilidad entre los casos analizados (CV 173%, rango: -18 a >100%. Sólo 11 de los 32 casos analizados presentaron diferencias significativas entre el tratamiento inoculado y el control. No se detectó un patrón definido que permita explicar la alta heterogeneidad de los resultados, sin embargo, se podría especular, que los principales factores que pueden haber afectado el grado de colonización son: el estrés hídrico y el origen de las cepas del inoculante. Bajo condiciones de estrés puede existir una fuerte competencia entre las poblaciones rizosféricas, situación en la cual, las cepas nativas tienen ventaja por su mayor adaptación al medio.The effectivity of inoculation with Azospirillum spp. often lacks consistency under field conditions. Microbial colonization of the rhizosphere is considered a prerequisite for successful inoculation. The objective of this study was to determine the degree of rhizosphere colonization in 11 field inoculation assays under different treatments (sites, crops, strains, cultivars, etc. performed in the semiarid central region of Argentina in the last 15 years, conforming a total of 32 study cases. For comparative purposes, all the assays were performed following the same experimental design and inoculation and analytic methods. Variation results relative to control treatment were clustered

  17. Uso tradicional y actual de spirulina sp. (Arthrospira sp.)

    OpenAIRE

    Liliana Ramírez- Moreno; Roxana Olvera-Ramírez

    2006-01-01

    Spirulina sp. (Arthrospira sp.) es una cianobacteria filamentosa no diferenciada, habitante de lagos alcalinos, que se cultiva para consumo humano debido a su contenido nutricional. En México, el consumo de esta cianobacteria se remonta a tiempos prehispánicos, cuando era conocida como tecuitlatl, siendo conocida como dihé por las tribus nativas de la región del lago de Chad, en África. En los últimos años se le han atribuido diversos efectos positivos en el tratamiento de algunos tipos de al...

  18. PRODUTIVIDADE DO TRIGO IRRIGADO SUBMETIDO À APLICAÇÃO DE NITROGÊNIO E À INOCULAÇÃO COM AZOSPIRILLUM BRASILENSE

    Directory of Open Access Journals (Sweden)

    Pedro Henrique Marques Paula Nunes

    2015-02-01

    Full Text Available Inocular sementes de trigo com Azospirillum brasilense pode ser benéfico à cultura do trigo, bem como reduzir a necessidade de aplicação de N. No entanto, são escassos trabalhos que mensurem o benefício dessa prática no trigo irrigado com expectativa de alta produtividade e demanda de N. Objetivou-se com este trabalho avaliar a produtividade e o conteúdo de N na planta do trigo irrigado, submetido a doses de N, com ou sem a inoculação com A. brasilense. Foram conduzidos dois experimentos em 2011 e repetidos em 2012. Em cada ano de cultivo, instalou-se um experimento na área considerada de baixa disponibilidade de N no solo (cultivo em sucessão ao milho e outro na com alta disponibilidade (cultivo em sucessão à soja ou cenoura. Os tratamentos consistiram de cinco doses de N e da inoculação ou não com A. brasilense. As doses de N testadas foram 20, 60, 100, 140 e 180 kg ha-1 na área com baixa disponibilidade de N e 20, 50, 80, 110 e 140 kg ha-1 na com alta disponibilidade. O teor de N na folha índice foi aumentado pela inoculação com A. brasilense. Entretanto, o N absorvido não foi influenciado pela inoculação da bactéria. As doses de N aumentaram a produtividade do trigo e esse aumento foi mais evidente no cultivo na área com baixa disponibilidade de N no solo.

  19. Adubação nitrogenada associada à inoculação com Azospirillum brasilense e Herbaspirillum seropedicae na cultura do milho

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    Janaína Dartora

    2013-10-01

    Full Text Available Bactérias dos gêneros Azospirillum e Herbaspirillum são fixadoras de nitrogênio (N atmosférico e consideradas promotoras do crescimento vegetal. Desta forma, desenvolveu-se o presente trabalho com o objetivo de avaliar o desenvolvimento e a produtividade do milho em resposta à inoculação de A. brasilense e H. seropedicae associada à adubação nitrogenada. O experimento foi conduzido em delineamento experimental de blocos ao acaso em esquema fatorial 4 x 5, com quatro repetições. Os tratamentos foram constituídos da inoculação de sementes (testemunha, estirpe de A. brasilense - Ab-V5, estirpe de H. seropedicae - SmR1 e combinação Ab-V5 + SmR1 e doses de N (0, 40, 80, 120 e 160 kg ha-1 de N. Foram avaliados: diâmetro basal do colmo, altura de planta, matéria seca de parte aérea e área foliar, nas fases vegetativa e reprodutiva, e produtividade. A adubação nitrogenada favoreceu o desenvolvimento da cultura até a máxima dose estudada. A inoculação combinada das estirpes proporcionou incrementos de 12% na matéria seca de parte aérea e 7% na produtividade em relação à testemunha indicando benefícios da combinação de bactérias diazotróficas que interagem de forma diferenciada com a planta.

  20. Evaluación de la zeolita como soporte sólido para la formulación del biofertilizante Azospirillum

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    Dayamí Borges-Rodríguez

    2012-01-01

    Full Text Available Se realizó una caracterización física de la zeolita proveniente de los yacimientos de San Juan de la Yeras, con el objetivo de evaluar sus posibilidades para ser usada como soporte sólido en la formulación del biofertilizante Azospirillum. Se evaluaron fracciones de tres tamaños de partícula, de las que la fracción Zoac (<0,8 mm fue la más apropiada de acuerdo con sus características y disponibilidad. Se realizaron experimentos mediante un diseño factorial 22 para evaluar la estabilidad del inoculante formulado en soporte sólido, teniendo en cuenta dos niveles de relación de inoculación y concentración celular del producto. De acuerdo con los resultados obtenidos, el producto líquido no puede ser almacenado a temperatura ambiente por un período superior a 14 días, mientras que la zeolita provee al microorganismo de un ambiente adecuado para su mantenimiento por un período de 90 días. La inoculación más efectiva resultó ser la realizada al 21 % con una titulación del producto al salir del fermentador de 1 x 109 UFC/ml para una tasa de extinción celular de 1,4 x 106 cel/ml-1/día-1. La poca cantidad de inóculo líquido que es capaz de admitir este material y su bajo contenido de materia orgánica constituyen desventajas que debe ser consideradas para el establecimiento de una formulación definitiva del biofertilizante.

  1. Structural homologues P(II) and P(Z) of Azospirillum brasilense provide intracellular signalling for selective regulation of various nitrogen-dependent functions.

    Science.gov (United States)

    de Zamaroczy, M

    1998-07-01

    P(II) (glnB) is a signal transduction protein that in Azospirillum brasilense is specifically required for nitrogen fixation. Little is known about whether and how its homologue P(Z) (glnZ) participates in the regulation of cellular functions. In this study, we have shown the regulatory action of the two proteins by analysing the relevant single and double null-mutant strains. The transcription of glnZ is monocistronic, and it starts mainly from a sigma54-dependent promoter, activated by NtrC. glnZ expression is dependent on the ntr system, even under conditions of nitrogen excess, and is greatly enhanced in the presence of aspartate. P(Z) is uridylylated in response to nitrogen limitation, like P(II), although different amounts of the two proteins are synthesized. P(II) is required for the dephosphorylation of NtrC. Thus, in the absence of P(II), the repression of nitrate assimilation is not promoted, which, in turn, leads to a high rate of ammonium excretion. Unexpectedly, P(II) and P(Z) proteins are not essential for the reversible modification of glutamine synthetase. (Methyl)ammonium transport into the cell is negatively regulated by P(Z). The growth of a double-mutant strain (glnB::kan; glnZ::omega) is drastically disabled, although wild-type growth is restored by complementation with either glnB or glnZ. We conclude that P(II) and P(Z), despite their structural similarity, are involved in different regulatory processes, except for that required for cell growth.

  2. Different responses of the GlnB and GlnZ proteins upon in vitro uridylylation by the Azospirillum brasilense GlnD protein

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    L.M. Araújo

    2008-04-01

    Full Text Available Azospirillum brasilense is a diazotroph found in association with important agricultural crops. In this organism, the regulation of nitrogen fixation by ammonium ions involves several proteins including the uridylyltransferase/uridylyl-removing enzyme, GlnD, which reversibly uridylylates the two PII proteins, GlnB and GlnZ, in response to the concentration of ammonium ions. In the present study, the uridylylation/deuridylylation cycle of A. brasilense GlnB and GlnZ proteins by GlnD was reconstituted in vitro using the purified proteins. The uridylylation assay was analyzed using non-denaturing polyacrylamide gel electrophoresis and fluorescent protein detection. Our results show that the purified A. brasilense GlnB and GlnZ proteins were uridylylated by the purified A. brasilense GlnD protein in a process dependent on ATP and 2-oxoglutarate. The dependence on ATP for uridylylation was similar for both proteins. On the other hand, at micromolar concentration of 2-oxoglutarate (up to 100 µM, GlnB uridylylation was almost twice that of GlnZ, an effect that was not observed at higher concentrations of 2-oxoglutarate (up to 10 mM. Glutamine inhibited uridylylation and stimulated deuridylylation of both GlnB and GlnZ. However, glutamine seemed to inhibit GlnZ uridylylation more efficiently. Our results suggest that the differences in the uridylylation pattern of GlnB and GlnZ might be important for fine-tuning of the signaling pathway of cellular nitrogen status in A. brasilense.

  3. Different responses of the GlnB and GlnZ proteins upon in vitro uridylylation by the Azospirillum brasilense GlnD protein.

    Science.gov (United States)

    Araújo, L M; Huergo, L F; Invitti, A L; Gimenes, C I; Bonatto, A C; Monteiro, R A; Souza, E M; Pedrosa, F O; Chubatsu, L S

    2008-04-01

    Azospirillum brasilense is a diazotroph found in association with important agricultural crops. In this organism, the regulation of nitrogen fixation by ammonium ions involves several proteins including the uridylyltransferase/uridylyl-removing enzyme, GlnD, which reversibly uridylylates the two PII proteins, GlnB and GlnZ, in response to the concentration of ammonium ions. In the present study, the uridylylation/deuridylylation cycle of A. brasilense GlnB and GlnZ proteins by GlnD was reconstituted in vitro using the purified proteins. The uridylylation assay was analyzed using non-denaturing polyacrylamide gel electrophoresis and fluorescent protein detection. Our results show that the purified A. brasilense GlnB and GlnZ proteins were uridylylated by the purified A. brasilense GlnD protein in a process dependent on ATP and 2-oxoglutarate. The dependence on ATP for uridylylation was similar for both proteins. On the other hand, at micromolar concentration of 2-oxoglutarate (up to 100 microM), GlnB uridylylation was almost twice that of GlnZ, an effect that was not observed at higher concentrations of 2-oxoglutarate (up to 10 mM). Glutamine inhibited uridylylation and stimulated deuridylylation of both GlnB and GlnZ. However, glutamine seemed to inhibit GlnZ uridylylation more efficiently. Our results suggest that the differences in the uridylylation pattern of GlnB and GlnZ might be important for fine-tuning of the signaling pathway of cellular nitrogen status in A. brasilense.

  4. [Toxocara sp. eggs and Ancylostoma sp. larva in public parks, Brazil].

    Science.gov (United States)

    Guimarães, Antônio Marcos; Alves, Endrigo Gabellini Leonel; de Rezende, Glycia Ferreira; Rodrigues, Marcelo Costa

    2005-04-01

    Visceral and cutaneous larva migrans are parasitic zoonoses caused by the infection of larval nematodes Toxocara sp. and Ancylostoma sp. respectively. The objective of this study was to investigate the contamination by Toxocara sp. eggs and Ancylostoma sp. eggs and larva of soil samples collected from public parks and children's playground areas in state of Minas Gerais, Brazil, using both Baermann's method and centrifugal flotation technique. Toxocara sp. and Ancylostoma sp. eggs were observed in soil samples collected from public squares in 17.4% (4/23) and 69.6 (16/23) respectively. In schools and child day care settings the contamination by Ancylostoma sp. larva in sand samples was 11.1% (2/18). Public parks are settings of more potential risk of Toxocara sp. eggs and Ancylostoma sp. infection. Stool parasitology testing of 174 stool samples showed 58% and 23% of Ancylostoma sp and Toxocara sp eggs infection respectively.

  5. Lactobacillus apinorum sp. nov., Lactobacillus mellifer sp. nov., Lactobacillus mellis sp. nov., Lactobacillus melliventris sp. nov., Lactobacillus kimbladii sp. nov., Lactobacillus helsingborgensis sp. nov. and Lactobacillus kullabergensis sp. nov., isolated from the honey stomach of the honeybee Apis mellifera.

    Science.gov (United States)

    Olofsson, Tobias C; Alsterfjord, Magnus; Nilson, Bo; Butler, Eile; Vásquez, Alejandra

    2014-09-01

    We previously discovered a symbiotic lactic acid bacterial (LAB) microbiota in the honey stomach of the honeybee Apis mellifera. The microbiota was composed of several phylotypes of Bifidobacterium and Lactobacillus. 16S rRNA gene sequence analyses and phenotypic and genetic characteristics revealed that the phylotypes isolated represent seven novel species. One grouped with Lactobacillus kunkeei and the others belong to the Lactobacillus buchneri and Lactobacillus delbrueckii subgroups of Lactobacillus. We propose the names Lactobacillus apinorum sp. nov., Lactobacillus mellifer sp. nov., Lactobacillus mellis sp. nov., Lactobacillus melliventris sp. nov., Lactobacillus kimbladii sp. nov., Lactobacillus helsingborgensis sp. nov. and Lactobacillus kullabergensis sp. nov. for these novel species, with the respective type strains being Fhon13N(T) ( = DSM 26257(T) = CCUG 63287(T)), Bin4N(T) ( = DSM 26254(T) = CCUG 63291(T)), Hon2N(T) ( = DSM 26255(T) = CCUG 63289(T)), Hma8N(T) ( = DSM 26256(T) = CCUG 63629(T)), Hma2N(T) ( = DSM 26263(T) = CCUG 63633(T)), Bma5N(T) ( = DSM 26265(T) = CCUG 63301(T)) and Biut2N(T) ( = DSM 26262(T) = CCUG 63631(T)).

  6. Pantoea vagans sp. nov., Pantoea eucalypti sp. nov., Pantoea deleyi sp. nov. and Pantoea anthophila sp. nov.

    Science.gov (United States)

    Brady, Carrie L; Venter, Stephanus N; Cleenwerck, Ilse; Engelbeen, Katrien; Vancanneyt, Marc; Swings, Jean; Coutinho, Teresa A

    2009-09-01

    Bacteria isolated from eucalyptus leaves and shoots showing symptoms of blight and die-back collected in Uganda, Uruguay and Argentina and from maize displaying brown stalk rot symptoms in South Africa were tentatively placed in the genus Pantoea on the basis of phenotypic and biochemical tests. These isolates, together with two strains (LMG 2558 and LMG 2560) previously assigned to Pantoea agglomerans based on protein electrophoregrams but later excluded from this species, were further investigated using molecular techniques. 16S rRNA gene sequencing and multilocus sequence analyses (MLSA) revealed that the strains were phylogenetically closely related to Pantoea agglomerans, Pantoea stewartii and Pantoea ananatis. MLSA and amplified fragment length polymorphism analysis placed the strains into four separate clusters, not containing any of the type strains of species of the genus Pantoea. DNA-DNA hybridization confirmed the classification of the isolates into four novel species, for which the names Pantoea vagans sp. nov. (type strain R-21566T=LMG 24199T=BCC 105T=BD 765T), Pantoea eucalypti sp. nov. (type strain R-25678T=LMG 24197T=BCC 076T=BD 769T), Pantoea deleyi sp. nov. (type strain R-31523T=LMG 24200T=BCC 109T=BD 767T) and Pantoea anthophila sp. nov. (type strain LMG 2558T=BD 871T=NCPPB 1682T) are proposed. PMID:19620357

  7. An Sp1/Sp3 binding polymorphism confers methylation protection.

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    Yanis A Boumber

    Full Text Available Hundreds of genes show aberrant DNA hypermethylation in cancer, yet little is known about the causes of this hypermethylation. We identified RIL as a frequent methylation target in cancer. In search for factors that influence RIL hypermethylation, we found a 12-bp polymorphic sequence around its transcription start site that creates a long allele. Pyrosequencing of homozygous tumors revealed a 2.1-fold higher methylation for the short alleles (P<0.001. Bisulfite sequencing of cancers heterozygous for RIL showed that the short alleles are 3.1-fold more methylated than the long (P<0.001. The comparison of expression levels between unmethylated long and short EBV-transformed cell lines showed no difference in expression in vivo. Electrophorectic mobility shift assay showed that the inserted region of the long allele binds Sp1 and Sp3 transcription factors, a binding that is absent in the short allele. Transient transfection of RIL allele-specific transgenes showed no effects of the additional Sp1 site on transcription early on. However, stable transfection of methylation-seeded constructs showed gradually decreasing transcription levels from the short allele with eventual spreading of de novo methylation. In contrast, the long allele showed stable levels of expression over time as measured by luciferase and approximately 2-3-fold lower levels of methylation by bisulfite sequencing (P<0.001, suggesting that the polymorphic Sp1 site protects against time-dependent silencing. Our finding demonstrates that, in some genes, hypermethylation in cancer is dictated by protein-DNA interactions at the promoters and provides a novel mechanism by which genetic polymorphisms can influence an epigenetic state.

  8. Coberturas vegetais, doses de nitrogênio e inoculação de sementes com Azospirillum brasilense em arroz de terras altas no sistema plantio direto

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    Douglas de Castilho Gitti

    2012-01-01

    Full Text Available O arroz é importante fonte de energia e proteínas para a população mundial, principalmente na Ásia e Oceania. No Brasil, juntamente com o feijão, constitui a base da alimentação. Tecnologias sustentáveis que reduzam custos da produção e aumentem a produtividade do arroz podem garantir seu suprimento em períodos de alta demanda. O objetivo deste trabalho foi avaliar diferentes coberturas vegetais antecessoras (milheto [Pennisetum americanum], crotalária [Crotalaria juncea], guandu [Cajanus cajan], braquiária [Brachiaria ruziziensis], milheto + crotalária e milheto + guandu, doses de nitrogênio (N em cobertura (0, 40, 80 e 120 kg ha-1 e o efeito da inoculação de sementes com Azospirillum brasilense no arroz de terras altas em sistema plantio direto no desenvolvimento e na produtividade. Utilizou-se o delineamento experimental em blocos casualizados em esquema fatorial 6x4x2 com quatro repetições. O estudo foi desenvolvido em um Latossolo Vermelho, em Selvíria, Estado do Mato Grosso do Sul, Brasil, em 2011/2012. O cultivo do guandu antecedendo o arroz proporcionou maior produtividade do arroz somente em comparação a B. ruziziensi. A produtividade do arroz em função das doses de N em cobertura se ajustou a uma função quadrática. Não houve influência da inoculação de sementes com A. brasilense sobre a produtividade do arroz, porém houve interação entre a inoculação e as coberturas vegetais sobre o teor de N foliar, número de panículas por m², matéria seca de plantas de arroz e a massa de cem grãos.

  9. 巴西固氮螺菌Yu62在玉米根的定植%Colonization Pattern of Azospirillum brasilense Yu62 on Maize Roots

    Institute of Scientific and Technical Information of China (English)

    刘元; 陈三凤; 李季伦

    2003-01-01

    Plasmid pVK1001 which carried the gfp gene of GFPmut2, a mutant of GFP, was introduced into Azospirillum brasilense Yu62 by electroporation. Maize seedlings were inoculated with the GFP-labelled bacteria and grown gnotobiotically in flask with semi-solid agar medium. Observations were performed with confocal laser scanning microscopy (CLSM) and electron microscopy, respectively, at 8 d and 12 d after inoculation. Confocal laser scanning microscopy showed that A. brasilense Yu62 could penetrate into the cortex tissue, colonizing in the intercellular spaces of the parenchyma cells of the cortex tissue. Transmission and scanning electron microscopy (TEM) showed that the majority of the bacteria colonized on the root surface and only a minority of them resided in the root interior.%将GFPmut2质粒中的gfp基因 (编码绿色荧光蛋白)克隆到载体pVK100中,构建成重组质粒pVK1001.将pVK1001通过电转化方法导入到联合固氮菌巴西固氮螺菌Yu62中,获得GFP标记的巴西固氮螺菌Yu62菌株.用标记菌株接种限菌培养条件下生长的玉米(农大3318)幼苗,在接种后8 d、12 d,用激光共聚焦扫描显微镜进行观测,结果表明巴西固氮螺菌Yu62菌株能定植于玉米根部皮层的薄壁细胞间隙.用扫描电镜和超薄切片电镜观察表明,大多数细菌主要定植于根表,少数菌可进入玉米根组织内.

  10. Chemical composition and deoxynivalenol in wheat of Central- Southern Paraná: nitrogen fertilization in top dressing associated with Azospirillum brasilense

    Directory of Open Access Journals (Sweden)

    Thiago Montagner Souza

    2014-02-01

    Full Text Available The impact of agricultural management practices on the quality of grain was evaluated in wheat (Triticum aestivum L. BRS Tangará from the South Central region of Paraná State (Ponta Grossa in the crop years of 2010 and 2011. The field trial was carried out in succession with soybean (2010 and corn (2011. The treatments included inoculation of seeds with Azospirillum brasilense and increasing levels of nitrogen application in top dressing (0, 30, 60, 90 and 120 kg ha-1. The experimental design was in randomized block, factorial 2 x 5 (inoculation x N levels, with four replications. The parameters evaluated were water activity, moisture, protein, and grain contamination by deoxynivalenol (DON. The data were subjected to analysis of variance, comparison of means by Tukey’s test (p<0.05 and regression for nitrogen levels. The inoculation of seeds with A. brasilense increased the protein content in grain in 2010 (+1.6%; 16.9 g 100g-1 and 2011 (+1.7%, 15.7 g 100g-1, independently of the nitrogen level (p<0.01. Levels of nitrogen in 2010 presented a positive linear response with protein content, increasing by 14.2% using non-inoculated seeds (p<0.01, R2=0.955 and 14.4% for those inoculated with A. brasilense (p<0.01, R2=0.906. However, in 2011 a quadratic response was observed between nitrogen levels and protein content (p<0.01, R2=0.99, with stabilization or reduction in protein content using high levels of nitrogen (?120 kg ha-1. The contamination by DON was greater using high levels of nitrogen (3574 ?g kg-1, 120 kg ha-1; non-inoculated seeds in 2011, with a quadratic response between nitrogen levels and contamination of grains (p<0.05, R2=0.772. Furthermore, 37.5% of the samples presented contamination by DON higher than the maximum tolerated limit established by Brazilian legislation (2000 ?g kg-1; whole-wheat grain. The data demonstrates that proper management of nitrogen enhances intrinsic effects arising from plant breeding.

  11. Montagem e anotação parcial da sequência genômica da Bactéria Diazotrófica Azospirillum Brasilense FP2

    OpenAIRE

    Silveira, Leviston da

    2012-01-01

    Resumo: Bactérias fixadoras de nitrogênio ou diazotróficas são organismos capazes de reduzir o dinitrogênio atmosférico em amônia, um processo chamado fixação biológica de nitrogênio que é catalisado pela enzima nitrogenase. Azospirillum brasilense é uma bactéria fixadora capaz de se associar a raízes de gramíneas como trigo e arroz, e promover o crescimento do vegetal e aumento de produtividade. Neste trabalho utilizamos 5.768.466 milhões de seqüência de nucleotídeos obtidas em seqüenciador ...

  12. SP-A and SP-D in host defense against fungal infections and allergies.

    Science.gov (United States)

    Pandit, Hrishikesh; Madhukaran, Shanmuga P; Nayak, Annapurna; Madan, Taruna

    2012-01-01

    Innate immunity mediated by pattern recognition proteins is relevant in the host defense against fungi. SP-A and SP-D are two such proteins belonging to the class of collagen domain containing C-type lectins, or collectins. They bind to the sugar moieties present on the cell walls of various fungi in a dose dependent manner via their carbohydrate recognition domain (CRD). SP-A and SP-D directly interact with alveolar macrophages, neutrophils, lymphocytes. We review these roles of SP-A and SP-D against various clinically relevant fungal pathogens and fungal allergens. SP-A and SP-D gene deficient mice showed increased susceptibility/ resistance to various fungal infections. Patients of fungal infections and allergies are reported with alterations in the serum or lung lavage levels of SP-A and SP-D. There are studies associating the gene polymorphisms in SP-A and SP-D with alterations in their levels or functions or susceptibility of the host to fungal diseases. In view of the protective role of SP-D in murine models of Aspergillus fumigatus infections and allergies, therapeutic use of SP-D could be explored further.

  13. Identificação de isolados de Azospirillum amazonense associados a Brachiaria spp., em diferentes épocas e condições de cultivo e produção de fitormônio pela bactéria Identification of Azospirillum amazonense isolates associated to Brachiaria spp. at different stages and growth conditions, and bacterial plant hormone production

    Directory of Open Access Journals (Sweden)

    F. B. Reis Junior

    2004-02-01

    Full Text Available Existem evidências de que pastagens formadas por algumas espécies do gênero Brachiaria poderiam beneficiar-se com o processo de fixação biológica do nitrogênio atmosférico (FBN, garantindo a estas pastagens maior longevidade. Dentre as bactérias diazotróficas encontradas em associação com estas gramíneas forrageiras, destaca-se a espécie Azospirillum amazonense. Neste trabalho, objetivou-se verificar a influência da espécie de Brachiaria, manejo da pastagem e sazonalidade sobre as populações de A. amazonense associadas às raízes destas plantas. Diferentes pastagens (B. humidicola, B. decumbens e B. brizantha foram introduzidas em regiões do ecossistema Cerrado e de Mata Atlântica. Foram avaliados dois sistemas de manejo com diferentes taxas de lotação, e as coletas foram realizadas em diferentes épocas do ano. As populações de A. amazonense foram quantificadas e a identidade dos isolados confirmada, assim como sua capacidade de produção de fitormônios tipo AIA (ácido 3-indol acético em meio de cultivo. Isolados de A. amazonense foram obtidos a partir de amostras de raízes das três espécies de Brachiaria avaliadas. Estimativas das populações desta bactéria variaram de 10³-10(7 células g-1 de raízes. Em amostras do ecossistema Cerrado, a época de coleta apresentou efeito significativo sobre a população destas bactérias. Os dados da região de Mata Atlântica mostraram que plantas de Brachiaria de diferentes espécies e pastagens sob diferentes taxas de lotação podem apresentar números populacionais distintos associados às suas raízes. A técnica de análise de restrição do DNA ribossomal amplificado (ARDRA confirmou a identidade de todos os isolados avaliados. Estes isolados foram capazes de produzir fitormônios tipo AIA.There is evidence that pastures formed by some species of the genus Brachiaria could be benefited by the biological nitrogen fixation process (BNF, which would give these

  14. Coberturas vegetais, doses de nitrogênio e inoculação de sementes com Azospirillum brasilense em arroz de terras altas no sistema plantio direto Cover crops, nitrogen rates and seeds inoculation with Azospirillum brasilense in upland rice under no-tillage

    Directory of Open Access Journals (Sweden)

    Douglas de Castilho Gitti

    2013-01-01

    Full Text Available O arroz é importante fonte de energia e proteínas para a população mundial, principalmente na Ásia e Oceania. No Brasil, juntamente com o feijão, constitui a base da alimentação. Tecnologias sustentáveis que reduzam custos da produção e aumentem a produtividade do arroz podem garantir seu suprimento em períodos de alta demanda. O objetivo deste trabalho foi avaliar diferentes coberturas vegetais antecessoras (milheto [Pennisetum americanum], crotalária [Crotalaria juncea], guandu [Cajanus cajan], braquiária [Brachiaria ruziziensis], milheto + crotalária e milheto + guandu, doses de nitrogênio (N em cobertura (0, 40, 80 e 120 kg ha-1 e o efeito da inoculação de sementes com Azospirillum brasilense no arroz de terras altas em sistema plantio direto no desenvolvimento e na produtividade. Utilizou-se o delineamento experimental em blocos casualizados em esquema fatorial 6x4x2 com quatro repetições. O estudo foi desenvolvido em um Latossolo Vermelho, em Selvíria, Estado do Mato Grosso do Sul, Brasil, em 2011/2012. O cultivo do guandu antecedendo o arroz proporcionou maior produtividade do arroz somente em comparação a B. ruziziensi. A produtividade do arroz em função das doses de N em cobertura se ajustou a uma função quadrática. Não houve influência da inoculação de sementes com A. brasilense sobre a produtividade do arroz, porém houve interação entre a inoculação e as coberturas vegetais sobre o teor de N foliar, número de panículas por m², matéria seca de plantas de arroz e a massa de cem grãos.Rice is an important source of energy and protein for the world population, mainly in Asia and Oceania. In Brazil, together with common beans, it is the population's basic food. Sustainable technologies that reduce rice production costs and increase productivity can warrant its supply on period of high demand. The objective of this study was to evaluate different preceding cover crops (millet [Pennisetum americanum

  15. Coberturas vegetais, doses de nitrogênio e inoculação de sementes com Azospirillum brasilense em arroz de terras altas no sistema plantio direto Cover crops, nitrogen rates and seeds inoculation with Azospirillum brasilense in upland rice under no-tillage

    Directory of Open Access Journals (Sweden)

    Douglas de Castilho Gitti

    2012-01-01

    Full Text Available O arroz é importante fonte de energia e proteínas para a população mundial, principalmente na Ásia e Oceania. No Brasil, juntamente com o feijão, constitui a base da alimentação. Tecnologias sustentáveis que reduzam custos da produção e aumentem a produtividade do arroz podem garantir seu suprimento em períodos de alta demanda. O objetivo deste trabalho foi avaliar diferentes coberturas vegetais antecessoras (milheto [Pennisetum americanum], crotalária [Crotalaria juncea], guandu [Cajanus cajan], braquiária [Brachiaria ruziziensis], milheto + crotalária e milheto + guandu, doses de nitrogênio (N em cobertura (0, 40, 80 e 120 kg ha-1 e o efeito da inoculação de sementes com Azospirillum brasilense no arroz de terras altas em sistema plantio direto no desenvolvimento e na produtividade. Utilizou-se o delineamento experimental em blocos casualizados em esquema fatorial 6x4x2 com quatro repetições. O estudo foi desenvolvido em um Latossolo Vermelho, em Selvíria, Estado do Mato Grosso do Sul, Brasil, em 2011/2012. O cultivo do guandu antecedendo o arroz proporcionou maior produtividade do arroz somente em comparação a B. ruziziensi. A produtividade do arroz em função das doses de N em cobertura se ajustou a uma função quadrática. Não houve influência da inoculação de sementes com A. brasilense sobre a produtividade do arroz, porém houve interação entre a inoculação e as coberturas vegetais sobre o teor de N foliar, número de panículas por m², matéria seca de plantas de arroz e a massa de cem grãos.Rice is an important source of energy and protein for the world population, mainly in Asia and Oceania. In Brazil, together with common beans, it is the population's basic food. Sustainable technologies that reduce rice production costs and increase productivity can warrant its supply on period of high demand. The objective of this study was to evaluate different preceding cover crops (millet [Pennisetum americanum

  16. Comparación entre coinoculación con Bradyrhizobium japonicum y Azospirillum brasilense e inoculación simple con Bradyrhizobium japonicum en la nodulación, crecimiento y acumulación de N en el cultivo de soja Comparison of coinoculation with Bradyrhizobium japonicum and Azospirillum brasilense with inoculation with Bradyrhizobium japonicum on nodulation, growth, and N accumulation in the soybean crop

    Directory of Open Access Journals (Sweden)

    S. Benintende

    2010-12-01

    Full Text Available El objetivo fue comparar la coinoculación con Bradyrhizobium japonicum y Azospirillum brasilense con relación a la inoculación simple con Bradyrhizobium japonicum en la nodulación, crecimiento y acumulación de N en el cultivo de soja y su rendimiento. Se realizaron dos experimentos en lotes en los que nunca se cultivó soja en años con diferentes condiciones hídricas. Los tratamientos fueron: testigo (sin inoculación, coinoculación con Bradyrhizobium japonicum y Azospirillum brasilense e inoculación simple con Bradyrhizobium japonicum. La nodulación en ambos experimentos fue superior en la coinoculación, aunque hubo diferencias significativas en el experimento con déficit hídrico. Los rendimientos, en ambos experimentos, presentaron valores medios superiores en la coinoculación, aunque sin diferencias significativas. La acumulación de biomasa aérea y N fue mayor en el año húmedo. El porcentaje de N derivado de la fijación biológica de N en el cultivo en el año seco fue de 26% para la inoculación simple y de 30% en la coinoculación, mientras que en el año húmedo este porcentaje fue de 41 y 47% respectivamente. A partir de estos resultados se concluye que existe un efecto de estimulación del crecimiento del cultivo de soja por la coinoculación. Sin embargo, es necesario continuar con estudios sobre este tema.The aim of this study was to compare coinoculation with Bradyrhizobium japonicum and Azospirillum brasilense with inoculation with Bradyrhizobium japonicum on nodulation, growth, and N accumulation in the soybean crop in field conditions. Two field tests were carried out for two years with different hydric conditions in areas not previously cultivated with soybean. The treatments were: control, coinoculation using Bradyrhizobium japonicum + Azospirillum brasilense and inoculation with Bradyrhizobium japonicum. Nodulation in both experiments was increased by dual inoculation, although significant differences were

  17. Potensi Tanaman Ornamental (Aglaonema sp., Dieffenbachia sp., dan Spathiphyllum sp.) dalam Menurunkan Jumlah Mikroba Udara dalam Ruangan Kelas Sekolah Dasar

    OpenAIRE

    Mangunsong, Sisca Nency Teresia

    2016-01-01

    Bioaerosol is dust particles consisting of bacteria and other fungi with spores that are in the room when the temperature and humidity level are adequate. Its presence in the room are generally harmless, but some time causes disease. This research was aims to determine the effect of ornamental plant Aglaonema sp., Dieffenbachia sp., and Spathiphyllum sp. on amount of bacteria and fungi in the class room. Bioaerosol isolation was performed according to the method of air sampling with three rep...

  18. DISTRIBUSI Solen sp DI PERAIRAN KABUPATEN BANGKALAN

    Directory of Open Access Journals (Sweden)

    Eva Ari Wahyuni

    2016-03-01

    Full Text Available DISTRIBUTION OF Solen sp IN BANGKALAN WATERSSolen sp potential needs to be developed on the island of Madura, particularly in Bangkalan. Solen sp utilization has increased which has the potential to overfishing. Therefore, this study aims to determine the density of Solen sp and their ecology in the waters Modung village, Modung District, Bangkalan. The experiment was conducted in April 2015 using the descriptive method. The materials used include Solen sp and physico-chemical parameters of the environment (temperature, salinity, pH, and substrate. The analyzes were conducted at the Laboratory of Marine Science, Department of Marine Sciences, Trunojoyo University of Madura by using the tool grabsampler, sieveshaker, and pipetting with gravimetric method. The analysis shows the range of values of temperature between 29-300C, salinity between 31-32 ppt, pH were 7.9-8.0 and the type of substrate in the form of sandy mud, as well as the density of Solen sp from 8-10 individuals/m2. All measurement results indicate normal conditions and in accordance with the sea water quality standard for marine life, which can be a suitable habitat for the growth and development of Solen sp. This condition is thought to affect the density of Solen sp.Keywords: Bangkalan, density, distribution, Solen sp, substrate.ABSTRAKPotensi Solen sp perlu dikembangkan di pulau Madura, khususnya di Kabupaten Bangkalan. Pemanfaatan Solen sp mengalami peningkatan sehingga berpotensi overfishing. Untuk itu, penelitian ini bertujuan untuk mengetahui kepadatan Solen sp dan ekologinya di perairan desa Modung, Kecamatan Modung, Kabupaten Bangkalan. Penelitian dilaksanakan pada bulan April 2015 dengan metode deskriptif. Materi dan bahan yang digunakan diantaranya Solen sp dan parameter fisika-kimia lingkungan (suhu, salinitas, pH, dan substrat. Analisa dilakukan di Laboratorium Ilmu Kelautan, Program studi/Jurusan Ilmu Kelautan Universitas Trunojoyo Madura dengan menggunakan alat

  19. Fungi Association with Cedar’s Seeds and Fusarium sp. and Pestalotia sp. Pathogenicities Levantamento de Fungos em Sementes de Cedro e Avaliação da Patogenicidade de Fusarium sp. e Pestalotia sp.

    Directory of Open Access Journals (Sweden)

    Sílvia Cristina Benetti

    2010-02-01

    Full Text Available

    This research had as main objectives the evaluation of cedar’s seeds seed-borne fungi and the Fusarium
    sp. and Pestalotia sp. pathogenicities. For the fungi detection Potato Dextrose and Agar medium and Blotter
    test methods were used. For the pathogenicity tests, isolates of Fusarium sp. and Pestalotia sp. were used. The following fungi were observed: Pestalotia sp., Fusarium sp., Phomopsis sp., Colletotrichum sp., Macrophomina sp. and Cladosporium sp. The fungi observed in the highest frequencies were: Fusarium sp., Phomopsis sp. and Pestalotia sp. A reduction of the germination level was observed in seedlings from cedar’s seed inoculated with Fusarium sp.

     

    doi: 10.4336/2009.pfb.58.81

    Este trabalho teve por objetivos avaliar fungos em sementes de cedro e testar a patogenicidade de Fusarium sp. e Pestalotia sp. Para detecção de fungos, foram utilizados batata-dextrose-ágar e papel filtro. Para o teste de patogenicidade, utilizaram-se isolados de Fusarium sp. e de Pestalotia sp. Foi constatada a presença dos seguintes fungos nas sementes: Pestalotia sp., Fusarium sp., Phomopsis sp., Colletotrichum sp., Macrophomina sp. e Cladosporium sp. Os fungos de maior freqüência foram: Fusarium sp., Phomopsis sp. e Pestalotia sp. Observou-se decréscimo nos valores de emergência das plântulas oriundas das sementes inoculadas com Fusarium sp.

     

    Doi: 10.4336/2009.pfb.58.81

  20. Babesia sp. in Colombian bats (Microchiroptera).

    Science.gov (United States)

    Marinkelle, C J

    1996-07-01

    Two leaf-chinned bats (Mormoops megalophylla) collected in 1963 in central Colombia were heavily infected with Babesia sp., probably Babesia vesperuginis. Both bats had pronounced splenomegaly. This is the first report of a Babesia sp. infection of a bat in the Americas. PMID:8827683

  1. Glyphosate catabolism by Pseudomonas sp

    International Nuclear Information System (INIS)

    The pathway for the degradation of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. PG2982 has been determined using metabolic radiolabeling experiments. Radiorespirometry experiments utilizing [3-14C] glyphosate revealed that approximately 50-59% of the C3 carbon was oxidized to CO2. Fractionation of stationary phase cells labeled with [3-14C]glyphosate revealed that from 45-47% of the assimilated C3 carbon is distributed to proteins and that amino acids methionine and serine are highly labeled. The nucleic acid bases adenine and guanine received 90% of the C3 label that was incorporated into nucleic acids, and the only pyrimidine base labeled was thymine. Pulse labeling of PG2982 cells with [3-14C]glyphosate revealed that [3-14C]sarcosine is an intermediate in glyphosate degradation. Examination of crude extracts prepared from PG2982 cells revealed the presence of an enzyme that oxidizes sarcosine to glycine and formaldehyde. These results indicate that the first step in glyphosate degradation by PG2982 is cleavage of the carbon-phosphorus bond, resulting in the release of sarcosine and a phosphate group. The phosphate group is utilized as a source of phosphorus, and the sarcosine is degraded to glycine and formaldehyde. Phosphonate utilization by Pseudomonas sp. PG2982 was investigated. Each of the ten phosphonates tested were utilized as a sole source of phosphorus by PG2982. Representative compounds tested included alkylphosphonates, 1-amino-substituted alkylphosphonates, amino-terminal phosphonates, and an arylphosphonate. PG2982 cultures degraded phenylphosphonate to benzene and produced methane from methylphosphonate. The data indicate that PG2982 is capable of cleaving the carbon-phosphorus bond of several structurally different phosphonates

  2. Listeria floridensis sp. nov., Listeria aquatica sp. nov., Listeria cornellensis sp. nov., Listeria riparia sp. nov. and Listeria grandensis sp. nov., from agricultural and natural environments.

    Science.gov (United States)

    den Bakker, Henk C; Warchocki, Steven; Wright, Emily M; Allred, Adam F; Ahlstrom, Christina; Manuel, Clyde S; Stasiewicz, Matthew J; Burrell, Angela; Roof, Sherry; Strawn, Laura K; Fortes, Esther; Nightingale, Kendra K; Kephart, Daniel; Wiedmann, Martin

    2014-06-01

    Sampling of agricultural and natural environments in two US states (Colorado and Florida) yielded 18 Listeria-like isolates that could not be assigned to previously described species using traditional methods. Using whole-genome sequencing and traditional phenotypic methods, we identified five novel species, each with a genome-wide average BLAST nucleotide identity (ANIb) of less than 85% to currently described species. Phylogenetic analysis based on 16S rRNA gene sequences and amino acid sequences of 31 conserved loci showed the existence of four well-supported clades within the genus Listeria; (i) a clade representing Listeria monocytogenes, L. marthii, L. innocua, L. welshimeri, L. seeligeri and L. ivanovii, which we refer to as Listeria sensu stricto, (ii) a clade consisting of Listeria fleischmannii and two newly described species, Listeria aquatica sp. nov. (type strain FSL S10-1188(T) = DSM 26686(T) = LMG 28120(T) = BEI NR-42633(T)) and Listeria floridensis sp. nov. (type strain FSL S10-1187(T) = DSM 26687(T) = LMG 28121(T) = BEI NR-42632(T)), (iii) a clade consisting of Listeria rocourtiae, L. weihenstephanensis and three novel species, Listeria cornellensis sp. nov. (type strain TTU A1-0210(T) = FSL F6-0969(T) = DSM 26689(T) = LMG 28123(T) = BEI NR-42630(T)), Listeria grandensis sp. nov. (type strain TTU A1-0212(T) = FSL F6-0971(T) = DSM 26688(T) = LMG 28122(T) = BEI NR-42631(T)) and Listeria riparia sp. nov. (type strain FSL S10-1204(T) = DSM 26685(T) = LMG 28119(T) = BEI NR- 42634(T)) and (iv) a clade containing Listeria grayi. Genomic and phenotypic data suggest that the novel species are non-pathogenic.

  3. Predictive value of Sp1/Sp3/FLIP signature for prostate cancer recurrence.

    Directory of Open Access Journals (Sweden)

    Roble G Bedolla

    Full Text Available Prediction of prostate cancer prognosis is challenging and predictive biomarkers of recurrence remain elusive. Although prostate specific antigen (PSA has high sensitivity (90% at a PSA level of 4.0 ng/mL, its low specificity leads to many false positive results and considerable overtreatment of patients and its performance at lower ranges is poor. Given the histopathological and molecular heterogeneity of prostate cancer, we propose that a panel of markers will be a better tool than a single marker. We tested a panel of markers composed of the anti-apoptotic protein FLIP and its transcriptional regulators Sp1 and Sp3 using prostate tissues from 64 patients with recurrent and non-recurrent cancer who underwent radical prostatectomy as primary treatment for prostate cancer and were followed with PSA measurements for at least 5 years. Immunohistochemical staining for Sp1, Sp3, and FLIP was performed on these tissues and scored based on the proportion and intensity of staining. The predictive value of the FLIP/Sp1/Sp3 signature for clinical outcome (recurrence vs. non-recurrence was explored with logistic regression, and combinations of FLIP/Sp1/Sp3 and Gleason score were analyzed with a stepwise (backward and forward logistic model. The discrimination of the markers was identified by sensitivity-specificity analysis and the diagnostic value of FLIP/Sp1/Sp3 was determined using area under the curve (AUC for receiver operator characteristic curves. The AUCs for FLIP, Sp1, Sp3, and Gleason score for predicting PSA failure and non-failure were 0.71, 0.66, 0.68, and 0.76, respectively. However, this increased to 0.93 when combined. Thus, the "biomarker signature" of FLIP/Sp1/Sp3 combined with Gleason score predicted disease recurrence and stratified patients who are likely to benefit from more aggressive treatment.

  4. PENGARUH FILTRAT CENDAWAN Aspergillus sp. DAN Fusarium sp. TERHADAP VIABILITAS BENIH DAN PERTUMBUHAN BIBIT SENGON (Paraserianthes falcataria)

    OpenAIRE

    Naning Yuniarti; Tati Suharti; Yulianti Bramasto

    2013-01-01

    Fungi are one of the main causes of damage to seeds. Fungi can be a pathogen or saprophyte such as Aspergillus sp. and Fusarium sp. The purpose of this study was to determine the effects of filtrate fungus Aspergillus sp and Fusarium sp on seed viability and seedling growth performance of Sengon (Paraserianthes falcataria). The experiment design used was the Completely Randomized Design (CRD), with treatment: control, filtrate of Aspergillus sp and Fusarium sp filtrate. Each treatment was rep...

  5. Fresh Water Cyanobacteria Geitlerinema sp. CCC728 and Arthrospira sp. CCC729 as an Anticancer Drug Resource

    OpenAIRE

    Akanksha Srivastava; Ratnakar Tiwari; Vikas Srivastava; Tej Bali Singh; Ravi Kumar Asthana

    2015-01-01

    An increasing number of cancer patients worldwide, especially in third world countries, have raised concern to explore natural drug resources, such as the less explored fresh water filamentous cyanobacteria. Six strains of cyanobacteria (Phormidium sp. CCC727, Geitlerinema sp. CCC728, Arthrospira sp. CCC729, Phormidium sp. CCC731, Phormidium sp. CCC730, and Leptolyngbya sp. CCC732) were isolated (paddy fields and ponds in the Banaras Hindu University, campus) and five strains screened for ant...

  6. Isolation and identification of an endophytic bacteria Azospirillum melinis against Rhizoctonia solani%水稻纹枯病生防内生菌糖蜜草固氮螺菌的分离与鉴定

    Institute of Scientific and Technical Information of China (English)

    王兰英; 谢颖; 廖凤仙; 王琼; 骆焱平

    2012-01-01

    Twenty-seven endophytic bacterial strains isolated from Fructus amomi were tested for in vitro antagonistic activity, pot experiment and field trial against the rice sheath blight pathogen, Rhizoctonia solani. The results revealed that 4 of the 27 isolates showed good anti-fungal activity against Rhizoctonia solani, of which SRJ2-4 exhibited the best effect with an inhibition zone up to 18 mm in diameter. The control efficacy of SRJ2-4 strain in pot experiment and field trial were 80. 7% and 79. 4% respectively, significantly higher than those of other isolates. The yield of the field treated with SRJ2-4 was also found to be the highest, up to 488.79 kg · 667 m-2. According to the morphological analysis, physiological and biochemical determination and 16S rDNA sequence comparison, the strain SRJ24 was identified as Azospirillum melinis.%本文首先对砂仁内生细菌进行分离,以水稻纹枯病菌(Rhizoctonia solani)为靶标菌对获得菌株进行离体拮抗活性、盆栽及田间试验测定.结果表明:获得的27株内生细菌中有4株具有较好的离体抑菌活性,其中SRJ2-4抑菌效果最好,抑菌带达到18 mm;SRJ2-4的盆栽防效及田间防效分别为80.7%与79.4%,与其它菌株相比达极显著水平.SRJ2-4处理的亩产量为488.79kg,高于其他药剂处理.对该菌株形态、生理生化及16S rDNA序列进行分析,将该内生菌鉴定为糖蜜草固氮螺菌(Azospirillum melinis.

  7. Safradan İzole Edilen Campylobacter Sp.

    OpenAIRE

    Yorgancıgil, Birdal; Tezeren, Deniz; Balaban, Neriman; Terzioğlu, Serdar; Öztürk, Süheyla

    2009-01-01

    SüleymanDemirel Üniversitesi TIP FAKÜLTESİ DERGİSİ: 1997 Haziran; 4(3) Safradan İzole Edilen Campylobacter Sp. Birdal YORGANCIGİL Deniz TEZEREN Neriman BALABAN Serdar TERZlOĞLU Süheyla ÖZTÜRK Özet Campylobacter sp. 'in neden olduğu, gastrointestinal traktüs haricindeki lokal veya sistemik infeksiyon vakaları oldukça azdır. Bu çalışmada safradan izole edilen bir Campylobacter sp. olgusu incelenmiştir. Ankara Numune Hastanesi Cerrahi Kliniğinde koles...

  8. Uji Efektifitas Jamur Antagonis Trichoderma sp. Dan Gliocladium sp. Untuk Mengendalikan Penyakit Layu Fusarium

    OpenAIRE

    Nasution, Rima Yunisa

    2015-01-01

    Rima Yunisa Nasution. 2014. Effectiveness test on antagonist fungi Trichoderma sp. and Gliocladium Sp. to control fusarium disease (Fusarium oxysporum F.sp capsici) for chilli crop (Capsicum Annuum L.) at screen house. Supervised by Lahmuddin Lubis and Hassanuddin. The goal of the research is to examine antagonist fungi Trichoderma and Gliocladium virens towards F. Oxysporum that lead the fusarium disease for chilli crop at screen house. The research was conducted at Plant Dise...

  9. Metabolites from marine fungus Aspergillus sp.

    Digital Repository Service at National Institute of Oceanography (India)

    Wahidullah, S.; Rajmanickam, R.; DeSouza, L.

    Chemical examination of a methanolic extract of the marine fungus, Aspergillus sp., isolated from marine grass environment, yielded a steroid, ergosterol peroxide (1), and a mixture of known glyceride esters (2,3) of unsaturated fatty acids...

  10. Tubulinosema sp. Microsporidian Myositis in Immunosuppressed Patient

    OpenAIRE

    Choudhary, Maria M.; Metcalfe, Maureen G.; Arrambide, Kathryn; Bern, Caryn; Visvesvara, Govinda S.; Pieniazek, Norman J.; Bandea, Rebecca D.; Deleon-Carnes, Marlene; Adem, Patricia; Choudhary, Moaz M.; Zaki, Sherif R.; Saeed, Musab U.

    2011-01-01

    The Phylum Microsporidia comprises >1,200 species, only 15 of which are known to infect humans, including the genera Trachipleistophora, Pleistophora, and Brachiola. We report an infection by Tubulinosema sp. in an immunosuppressed patient.

  11. Silencing the SpMPK1, SpMPK2, and SpMPK3 Genes in Tomato Reduces Abscisic Acid—Mediated Drought Tolerance

    Directory of Open Access Journals (Sweden)

    Yan Liang

    2013-11-01

    Full Text Available Drought is a major threat to agriculture production worldwide. Mitogen-activated protein kinases (MAPKs play a pivotal role in sensing and converting stress signals into appropriate responses so that plants can adapt and survive. To examine the function of MAPKs in the drought tolerance of tomato plants, we silenced the SpMPK1, SpMPK2, and SpMPK3 genes in wild-type plants using the virus-induced gene silencing (VIGS method. The results indicate that silencing the individual genes or co-silencing SpMPK1, SpMPK2, and SpMPK3 reduced the drought tolerance of tomato plants by varying degrees. Co-silencing SpMPK1 and SpMPK2 impaired abscisic acid (ABA-induced and hydrogen peroxide (H2O2-induced stomatal closure and enhanced ABA-induced H2O2 production. Similar results were observed when silencing SpMPK3 alone, but not when SpMPK1 and SpMPK2 were individually silenced. These data suggest that the functions of SpMPK1 and SpMPK2 are redundant, and they overlap with that of SpMPK3 in drought stress signaling pathways. In addition, we found that SpMPK3 may regulate H2O2 levels by mediating the expression of CAT1. Hence, SpMPK1, SpMPK2, and SpMPK3 may play crucial roles in enhancing tomato plants’ drought tolerance by influencing stomatal activity and H2O2 production via the ABA-H2O2 pathway.

  12. Cloning of rat sp56, the homologue of mouse sperm ZP3 receptor-sp56

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Mouse sp56 is considered as one of the candidates for mouse zona pellucida 3 (mZP3) receptor. Up to date, its homologue has only been cloned from guinea pig, namely AM67. Based on the cDNA sequence of mouse sp56, we designed a pair of primer to amplify its homologue from rat testis cDNA. Using RT-PCR,two fragments of 743 bp and 938 bp were amplified. The PCR products show very high homology to mouse sp56. However, the 743 bp product completely lacks one of the seven Sushi domains of mouse sp56. Using the 743 bp product as the probe to detect the expression profile of sp56 in rat tissues, Northern blot shows that a ~2.0 kb mRNA expresses specifically in testis. Employed the RACE method, two full cDNA sequences of rat sp56 were obtained. A Mr ~42 KD band was detected in denatured and non-reducing protein sample of rat testis and sperm with anti-mouse sp56 monoclonal antibody by Western blot method. Rat sp56was localized on rat sperm head by the indirect immunofiuorescence method. Rat sp56 immunoreactivitywas detected from the early pachytene spermatocytes and throughout the spermatogenesis. Its cloning willfurther our understanding of the mechanism of the sperm-egg recognition and binding.

  13. Isolation and Identification of Azospirillum brasilense Excreting High Concentration of IAA and Ammonium%高产吲哚乙酸及高泌氨巴西固氨螺菌的筛选与鉴定

    Institute of Scientific and Technical Information of China (English)

    王继雯; 谢宝恩; 周伏忠; 陈晓飞

    2009-01-01

    目的:从玉米根际和土壤中分离具有高产吲哚乙酸较强的泌氨能力的巴西固氮螺菌.方法:分别通过半固体NFb培养基、CR培养基、LB培养基分离培养固氮菌株,并经过一系列菌落菌体形态特征、生理生化特性和16S rDNA序列测定等试验对其进行鉴定.结果:经分离纯化获得10株固氮菌,并鉴定均为巴西固氮螺菌(Azospirillum brasilense),其中菌株R7在甘油半固体培养基上能分泌约14mmol/L的氨,在添加了色氨酸的培养基中能够合成58.8μg/ml的吲哚-3-乙酸(IAA).结论:成功筛选得到一株既高产吲哚乙酸又有较强的泌氨能力的巴西固氮螺菌.

  14. Effects of over-expression of the regulatory enzymes DraT and DraG on the ammonium-dependent post-translational regulation of nitrogenase reductase in Azospirillum brasilense.

    Science.gov (United States)

    Huergo, Luciano F; Souza, Emanuel M; Steffens, Maria B R; Yates, M Geoffrey; Pedrosa, Fábio O; Chubatsu, Leda S

    2005-03-01

    Nitrogen fixation in Azospirillum brasilense is regulated at transcriptional and post-translational levels. Post-translational control occurs through the reversible ADP-ribosylation of dinitrogenase reductase (Fe Protein), mediated by the dinitrogenase reductase ADP-ribosyltransferase (DraT) and dinitrogenase reductase glycohydrolase (DraG). Although the DraT and DraG activities are regulated in vivo, the molecules responsible for such regulation remain unknown. We have constructed broad-host-range plasmids capable of over-expressing, upon IPTG induction, the regulatory enzymes DraT and DraG as six-histidine-N-terminal fused proteins (His). Both DraT-His and DraG-His are functional in vivo. We have analyzed the effects of DraT-His and DraG-His over-expression on the post-translational modification of Fe Protein. The DraT-His over-expression led to Fe Protein modification in the absence of ammonium addition, while cells over-expressing DraG-His showed only partial ADP-ribosylation of Fe Protein by adding ammonium. These results suggest that both DraT-His and DraG-His lose their regulation upon over-expression, possible by titrating out negative regulators.

  15. Functional analysis of the GAF domain of NifA in Azospirillum brasilense: effects of Tyr-->Phe mutations on NifA and its interaction with GlnB.

    Science.gov (United States)

    Chen, Sanfeng; Liu, Li; Zhou, Xiaoyu; Elmerich, Claudine; Li, Ji-Lun

    2005-06-01

    Regulation of NifA activity in Azospirillum brasilense depends on GlnB (a PII protein), and it was previously reported that the target of GlnB activity is the N-terminal domain of NifA. Furthermore, mutation of the Tyr residue at position 18 in the N-terminal domain resulted in a NifA protein that did not require GlnB for activity under nitrogen fixation conditions. We report here that a NifA double mutant in which the Tyr residues at positions 18 and 53 of NifA N-were simultaneously replaced by Phe (NifA-Y1853F) displays high nitrogenase activity, which is still regulatable by ammonia, but not by GlnB. The yeast two-hybrid technique was used to investigate whether GlnB can physically interact with wild-type and mutant NifA proteins. GlnB was found to interact directly with the N-terminal GAF domain of wild-type NifA, but not with its central or C-terminal domain. GlnB could still bind to the single NifA mutants Y18F and Y53F. In contrast, no interaction was detected between GlnB and the double mutant NifA-Y18/53F or between GlnB and NifA-Y43.

  16. CO-INOCULAÇÃO E MODOS DE APLICAÇÃO DE Bradyrhizobium japonicum e Azospirillum brasilense E ADUBAÇÃO NITROGENADA NA NODULAÇÃO DAS PLANTAS E RENDIMENTO DA CULTURA DA SOJA

    Directory of Open Access Journals (Sweden)

    Alessandro Lucca Braccini

    2016-03-01

    Full Text Available As new cultivation techniques arise, crops require the development of new technologies and management practices that aim higher yields with lower production cost. Thus, the objective of this study was to evaluate the efficiency of co-inoculation and different ways of application of Bradyrhizobium japonicum and Azospirillum brasilense and nitrogen fertilization on nodulation and yield of soybean. The experiment was established in November 2013 in an area located in the Iguatemi Experimental Farm, of State University of Maringá (UEM. The design was a randomized block with four replications. The treatments consisted of a control, fertilization with nitrogen (200 kg N ha-1, standard inoculation in seeds (liquid and peat inoculant, co-inoculation on seed and co-inoculation at sowing, using different doses of inoculant B. japonicum and A. brasilense. The following determinations were carried out in the field and in the laboratory: number of nodes at flowering, mass of nodules at flowering, the shoot dry mass, nitrogen content in the shoot, grain nitrogen content, number of pods/plant, thousand grain mass and yield. The results showed that inoculation through seed treatment with liquid inoculant presents an adequate option to farmers, in the conditions of this experiment. Nitrogen fertilization did not increase yield and yield components, being unnecessary.

  17. Estudio sobre la influencia de la inoculación de las rizobacterias Azospirillum brasilense y Pseudomonas fluorescens sobre el desarrollo morfológico y el contenido de aceites esenciales en las especies aromáticas Ocimum basilicum var. genovesse, Ocimum basilicum var. minimum, Petroselinum sativum var. lisa y Salvia officinalis.

    OpenAIRE

    Martos Trenado, Pilar

    2012-01-01

    En el presente estudio se analiza la influencia de la inoculación con Azospirillum brasilense, con Pseudomonas fluorescens y la inoculación conjunta con ambas rizobacterias en las especies de plantas aromáticas Ocimum basilicum var. genovesse, Ocimum basilicum var. minimum, Petroselinum sativum var. lisa y Salvia officinalis. Se evaluará su desarrollo morfológico, atendiendo a tres parámetros: la longitud del tallo, el peso fresco y la superficie foliar. Así como el posible incremento en el c...

  18. Chaenorhinum semispeluncarum sp. nov. and C. yildirimlii sp. nov. (Scrophulariaceae) from east Anatolia, Turkey

    DEFF Research Database (Denmark)

    Yildirim, Hasan; Tan, Kit; Senol, Serdar;

    2010-01-01

    Chaenorhinum semispeluncarum H. Yildirim, Kit Tan, S. Senol & A. Pirhan sp. nov. and C. yildirimlii Kit Tan, H. Yildirim, S. Senol & A. Pirhan sp. nov. (Scrophulariaceae, C. sect. Microrrhinum) from east Anatolia are described and illustrated. They are both narrow endemics related to the rare C. ...

  19. Expression of surfactant proteins SP-A and SP-D in murine decidua and immunomodulatory effects on decidual macrophages.

    Science.gov (United States)

    Madhukaran, Shanmuga Priyaa; Koippallil Gopalakrishnan, Aghila Rani; Pandit, Hrishikesh; Marri, Eswari Dodagatta-; Kouser, Lubna; Jamil, Kaiser; Alhamlan, Fatimah S; Kishore, Uday; Madan, Taruna

    2016-02-01

    Surfactant proteins SP-A and SP-D are pattern recognition innate immune molecules that belong to the C-type lectin family. In lungs, they play an important role in the clearance of pathogens and control of inflammation. SP-A and SP-D are also expressed in the female reproductive tract where they play an important role in pregnancy and parturition. However, the role of SP-A and SP-D expressed at the feto-maternal interface (decidua) remains unclear. Here, we have examined the expression of SP-A and SP-D in the murine decidua at 17.5 (pre-parturition) and 19.5dpc (near parturition) and their effect on lipopolysaccharide (LPS)-treated decidual macrophages. SP-A and SP-D were localized to stromal cells in the murine decidua at 17.5 and 19.5dpc in addition to cells lining the maternal spiral artery. Purified pre-parturition decidual cells were challenged with LPS with and without SP-A or SP-D, and expression of F4/80 and TNF-α were measured by flow cytometry. On their own, SP-A or SP-D did not affect the percentage of F4/80 positive cells while they suppressed the percentage of TNF-α positive cells. However, simultaneous addition of SP-A or SP-D, together with LPS, reduced TNF-α secreting F4/80 positive cells. It is likely that exogenous administration of SP-A and SP-D in decidua can potentially control infection and inflammation mediators during spontaneous term labor and infection-induced preterm labor. Thus, the presence of SP-A and SP-D in the murine decidua is likely to play a protective role against intrauterine infection during pregnancy. PMID:26421960

  20. Metallaphotoredox-catalysed sp3-sp3 cross-coupling of carboxylic acids with alkyl halides

    Science.gov (United States)

    Johnston, Craig P.; Smith, Russell T.; Allmendinger, Simon; MacMillan, David W. C.

    2016-08-01

    In the past 50 years, cross-coupling reactions mediated by transition metals have changed the way in which complex organic molecules are synthesized. The predictable and chemoselective nature of these transformations has led to their widespread adoption across many areas of chemical research. However, the construction of a bond between two sp3-hybridized carbon atoms, a fundamental unit of organic chemistry, remains an important yet elusive objective for engineering cross-coupling reactions. In comparison to related procedures with sp2-hybridized species, the development of methods for sp3-sp3 bond formation via transition metal catalysis has been hampered historically by deleterious side-reactions, such as β-hydride elimination with palladium catalysis or the reluctance of alkyl halides to undergo oxidative addition. To address this issue, nickel-catalysed cross-coupling processes can be used to form sp3-sp3 bonds that utilize organometallic nucleophiles and alkyl electrophiles. In particular, the coupling of alkyl halides with pre-generated organozinc, Grignard and organoborane species has been used to furnish diverse molecular structures. However, the manipulations required to produce these activated structures is inefficient, leading to poor step- and atom-economies. Moreover, the operational difficulties associated with making and using these reactive coupling partners, and preserving them through a synthetic sequence, has hindered their widespread adoption. A generically useful sp3-sp3 coupling technology that uses bench-stable, native organic functional groups, without the need for pre-functionalization or substrate derivatization, would therefore be valuable. Here we demonstrate that the synergistic merger of photoredox and nickel catalysis enables the direct formation of sp3-sp3 bonds using only simple carboxylic acids and alkyl halides as the nucleophilic and electrophilic coupling partners, respectively. This metallaphotoredox protocol is suitable for

  1. Metallaphotoredox-catalysed sp(3)-sp(3) cross-coupling of carboxylic acids with alkyl halides.

    Science.gov (United States)

    Johnston, Craig P; Smith, Russell T; Allmendinger, Simon; MacMillan, David W C

    2016-08-18

    In the past 50 years, cross-coupling reactions mediated by transition metals have changed the way in which complex organic molecules are synthesized. The predictable and chemoselective nature of these transformations has led to their widespread adoption across many areas of chemical research. However, the construction of a bond between two sp(3)-hybridized carbon atoms, a fundamental unit of organic chemistry, remains an important yet elusive objective for engineering cross-coupling reactions. In comparison to related procedures with sp(2)-hybridized species, the development of methods for sp(3)-sp(3) bond formation via transition metal catalysis has been hampered historically by deleterious side-reactions, such as β-hydride elimination with palladium catalysis or the reluctance of alkyl halides to undergo oxidative addition. To address this issue, nickel-catalysed cross-coupling processes can be used to form sp(3)-sp(3) bonds that utilize organometallic nucleophiles and alkyl electrophiles. In particular, the coupling of alkyl halides with pre-generated organozinc, Grignard and organoborane species has been used to furnish diverse molecular structures. However, the manipulations required to produce these activated structures is inefficient, leading to poor step- and atom-economies. Moreover, the operational difficulties associated with making and using these reactive coupling partners, and preserving them through a synthetic sequence, has hindered their widespread adoption. A generically useful sp(3)-sp(3) coupling technology that uses bench-stable, native organic functional groups, without the need for pre-functionalization or substrate derivatization, would therefore be valuable. Here we demonstrate that the synergistic merger of photoredox and nickel catalysis enables the direct formation of sp(3)-sp(3) bonds using only simple carboxylic acids and alkyl halides as the nucleophilic and electrophilic coupling partners, respectively. This metallaphotoredox

  2. Evaluation of nutrient components of Bangia sp.

    Institute of Scientific and Technical Information of China (English)

    李水军; 马家海; 纪焕红; 谢恩义

    2003-01-01

    General nutrient components including moisture, ash, crude protein, lipid and carbohy-drate, inorganic elements, photosynthetic pigments, amino acids and fatty acids of Bangia sp. Were an-alyzed and compared with Porphyra yezoensis. The results indicated that the content of protein, totalamino acids and free amino acids accounted for 47.2 %, 42.6 % and 3.3 % in dried Bangia sp. , respec-tively, all essential amino acids were present in relatively high levels and desirable composition. Lipidwas 1.8 %, in which the eicosapentaenoic acid (EPA) reached 50.5 %. In per 100 g dried material, thecontent of chlorophyll, carotenoids, phycoerythrin and phycocyanin accounted for 766, 208, 4 600 and2 963 mg, respectively. Inorganic elements necessary for human body were found to be abundant inBangia sp. The results showed that the nutritive value of Bangia sp. Was the highest among algae re-ported so far, and the industry of Bangia sp. Was provided with significant economic importance and de-veloping potential.

  3. Interaction of uranium with Pleurotus sp.

    Energy Technology Data Exchange (ETDEWEB)

    Ohnuki, Toshihiko; Sakamoto, Fuminori; Kozaki, Naofumi; Ozaki, Takuro; Samadfam, Mohammad [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-11-01

    Uptake of uranium by higher fungi, such as mushroom is little elucidated. We have studied the interaction of uranium with Pleurotus sp. (a mushroom) in pure culture over a wide range of U concentration (50-3000 mg/L). The Pleurotus sp. was cultured in two different media. One was rice bran medium, and the other was agar (yeast extract, peptone and dextrose) medium. The uptake of uranium in Pleurotus sp. was examined by alpha ray autoradiography (A,A), X-ray fluorescence spectroscopy (XRF) and scanning microcopy (SEM) equipped with EDS. In the agar medium, the higher uranium concentration gave lower growth of mycelia, and no fruiting body was observed. In the rice bran medium, the fruiting body was grown at U concentrations up to 1000 mg/L. The AA and XRF analysis showed that uranium taken up in the fruiting body was below the detection limit. The SEM-EDS analysis indicated that U was distributed in the limited region and was not transported to the mycelia far from U containing medium. It is concluded that uranium affects the growth of Pleurotus sp., and little uranium is taken up by Pleurotus sp. during the growth of both mycelia and fruiting body. (author)

  4. Interaction of uranium with Pleurotus sp

    International Nuclear Information System (INIS)

    Uptake of uranium by higher fungi, such as mushroom is little elucidated. We have studied the interaction of uranium with Pleurotus sp. (a mushroom) in pure culture over a wide range of U concentration (50-3000 mg/L). The Pleurotus sp. was cultured in two different media. One was rice bran medium, and the other was agar (yeast extract, peptone and dextrose) medium. The uptake of uranium in Pleurotus sp. was examined by alpha ray autoradiography (A,A), X-ray fluorescence spectroscopy (XRF) and scanning microcopy (SEM) equipped with EDS. In the agar medium, the higher uranium concentration gave lower growth of mycelia, and no fruiting body was observed. In the rice bran medium, the fruiting body was grown at U concentrations up to 1000 mg/L. The AA and XRF analysis showed that uranium taken up in the fruiting body was below the detection limit. The SEM-EDS analysis indicated that U was distributed in the limited region and was not transported to the mycelia far from U containing medium. It is concluded that uranium affects the growth of Pleurotus sp., and little uranium is taken up by Pleurotus sp. during the growth of both mycelia and fruiting body. (author)

  5. Bioaccumulation of Total and Methyl Mercury in Three Earthworm Species (Drawida sp., Allolobophora sp., and Limnodrilus sp.)

    OpenAIRE

    Zhang, Zhong Sheng; Zheng, Dong Mei; Wang, Qi Chao; Lv, Xian Guo

    2009-01-01

    We determined total and methyl mercury contents in soil, three earthworm species and their vomitus to study the species-specific differences of mercury bioconcentration in Huludao City, a heavily polluted region by chlor-alkali and nonferrous metal smelting industry in Liaoning Province, northeast China. Total and methyl mercury contents were 7.20 mg/kg and 6.94 ng/g in soil, 1.43 mg/kg and 43.03 ng/g in Drawida sp., 2.80 mg/kg and 336.52 ng/g in Alolobophora sp., respectively. Total mercury ...

  6. Five novel Wickerhamomyces- and Metschnikowia-related yeast species, Wickerhamomyces chaumierensis sp. nov., Candida pseudoflosculorum sp. nov., Candida danieliae sp. nov., Candida robnettiae sp. nov. and Candida eppingiae sp. nov., isolated from plants

    NARCIS (Netherlands)

    Groenewald, Marizeth; Robert, Vincent; Smith, Maudy Th

    2011-01-01

    On the basis of nucleotide divergences in the D1/D2 domain of the 26S rRNA gene and the internal transcribed spacers (ITS) domain of the rRNA gene, five novel yeast species, Wickerhamomyces chaumierensis sp. nov. (CBS 8565(T)  = JCM 17246(T)), Candida pseudoflosculorum sp. nov. (CBS 8584(T)  = JCM 1

  7. Surfactant Proteins SP-A and SP-D Modulate Uterine Contractile Events in ULTR Myometrial Cell Line.

    Directory of Open Access Journals (Sweden)

    Georgios Sotiriadis

    Full Text Available Pulmonary surfactant proteins SP-A and SP-D are pattern recognition innate immune molecules. However, there is extrapulmonary existence, especially in the amniotic fluid and at the feto-maternal interface. There is sufficient evidence to suggest that SP-A and SP-D are involved in the initiation of labour. This is of great importance given that preterm birth is associated with increased mortality and morbidity. In this study, we investigated the effects of recombinant forms of SP-A and SP-D (rhSP-A and rhSP-D, the comprising of trimeric lectin domain on contractile events in vitro, using a human myometrial cell line (ULTR as an experimental model. Treatment with rhSP-A or rhSP-D increased the cell velocity, distance travelled and displacement by ULTR cells. rhSP-A and rhSP-D also affected the contractile response of ULTRs when grown on collagen matrices showing reduced surface area. We investigated this effect further by measuring contractility-associated protein (CAP genes. Treatment with rhSP-A and rhSP-D induced expression of oxytocin receptor (OXTR and connexin 43 (CX43. In addition, rhSP-A and rhSP-D were able to induce secretion of GROα and IL-8. rhSP-D also induced the expression of IL-6 and IL-6 Ra. We provide evidence that SP-A and SP-D play a key role in modulating events prior to labour by reconditioning the human myometrium and in inducing CAP genes and pro-inflammatory cytokines thus shifting the uterus from a quiescent state to a contractile one.

  8. SP2Bench: A SPARQL Performance Benchmark

    CERN Document Server

    Schmidt, Michael; Lausen, Georg; Pinkel, Christoph

    2008-01-01

    Recently, the SPARQL query language for RDF has reached the W3C recommendation status. In response to this emerging standard, the database community is currently exploring efficient storage techniques for RDF data and evaluation strategies for SPARQL queries. A meaningful analysis and comparison of these approaches necessitates a comprehensive and universal benchmark platform. To this end, we have developed SP$^2$Bench, a publicly available, language-specific SPARQL performance benchmark. SP$^2$Bench is settled in the DBLP scenario and comprises both a data generator for creating arbitrarily large DBLP-like documents and a set of carefully designed benchmark queries. The generated documents mirror key characteristics and social-world distributions encountered in the original DBLP data set, while the queries implement meaningful requests on top of this data, covering a variety of SPARQL operator constellations and RDF access patterns. As a proof of concept, we apply SP$^2$Bench to existing engines and discuss ...

  9. Sp(3, R) coadjoint orbit theory

    International Nuclear Information System (INIS)

    The algebraic mean field method is applied to the symplectic Lie algebra sp(3, R) that describes geometrical collective states in atomic nuclei. The expectations of sp(3, R) generators define a symplectic density matrix. The mean field approximation restricts the densities to a manifold that is a coadjoint orbit of the transformation group Sp(3, R) and a level surface of the symplectic Casimir functions. Compared to representation theory, mean field theory is technically simpler, but yields similar predictions for physical properties of collective states. The critical points of the energy functional on a coadjoint orbit surface define rotational bands. The deformation, kinetic energy and Kelvin circulation of principal axis symplectic rotors are determined as a function of the angular momentum. Illustrative applications of coadjoint orbit theory are reported for the yrast rotational bands of a light 20Ne and a heavy 166Er deformed isotope. (author)

  10. BUSCANDO UM BIOHERBICIDA CONTRA Cyperus sp (tiririca

    Directory of Open Access Journals (Sweden)

    Cristine Benfatti Gonzalez

    2001-01-01

    Full Text Available As an alternative to conventional control of Cyperus sp (herbaceousnutsedge, with chemical products, it rises the biological control, making use of phytopathogenic microorganisms. As results of the whole production of Cercospora henningsii e Cercospora caricis by fermentation in potato-dextrose (PD liquid medium, it was observed that both species obtained the optimum growth at 36o C. C. henningsii attained the best value after a period of 72 h of fermentation and C. caricis attained it after 60 h. The field experiments, against Cyperus sp (nutsedge, with the obtained products by liquid fermentation of Cercospora sp (C. henningsii and/or C. caribaea, andwith the use of "wet chamber", proved the pathogenic potential bioherbicide of these microorganisms. = Como alternativa ao controle convencional do Cyperus sp (tiririca usando produtos químicos, surge o controle biológico, empregando-se microrganismos fitopatógenos. Como resultados da produção massal de Cercospora henningsii eCercospora caricis através de cultivo submerso em meio de cultura batata-dextrose (BD, observou-se que ambas espécies obtiveram um crescimento ótimo a 36o C, sendo que para C. henningsii se deu com 72 h de fermentação e para C. caricis com 60 h. Os experimentos de campo, bem como os de Câmara úmida, contra Cyperus sp (tiririca,com os produtos obtidos pelo cultivo submerso de Cercospora sp (C. henningsii e/ou C. caribaea, demonstraram a patogenicidade, ou seja, o potencial bioherbicida desses microrganismos.

  11. Analysis list: Sp1 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Sp1 Placenta,Pluripotent stem cell + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Sp1....1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Sp1.5.tsv http://dbarchive.biosc...iencedbc.jp/kyushu-u/mm9/target/Sp1.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Sp1.Placenta....tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Sp1.Pluripotent_stem_cell

  12. Blastocystis sp. Infection Mimicking Clostridium Difficile Colitis

    Science.gov (United States)

    Gil, Gaby S.; Chaudhari, Shobhana; Shady, Ahmed; Caballes, Ana; Hong, Joe

    2016-01-01

    We report an unusual case of severe diarrhea related to Blastocystis sp. infection in a patient with end stage renal disease on hemodialysis. The patient was admitted due to profuse diarrhea associated with fever and leukocytosis. Pertinent stool work-up such as leukocytes in stool, stool culture, clostridium difficile toxin B PCR, and serology for hepatitis A, hepatitis B, and hepatitis C and cytomegalovirus screening were all negative. Ova and parasite stool examination revealed Blastocystis sp. The patient was given intravenous metronidazole with clinical improvement by day three and total resolution of symptoms by day ten. PMID:27247810

  13. Blastocystis sp. Infection Mimicking Clostridium Difficile Colitis.

    Science.gov (United States)

    Gil, Gaby S; Chaudhari, Shobhana; Shady, Ahmed; Caballes, Ana; Hong, Joe

    2016-01-01

    We report an unusual case of severe diarrhea related to Blastocystis sp. infection in a patient with end stage renal disease on hemodialysis. The patient was admitted due to profuse diarrhea associated with fever and leukocytosis. Pertinent stool work-up such as leukocytes in stool, stool culture, clostridium difficile toxin B PCR, and serology for hepatitis A, hepatitis B, and hepatitis C and cytomegalovirus screening were all negative. Ova and parasite stool examination revealed Blastocystis sp. The patient was given intravenous metronidazole with clinical improvement by day three and total resolution of symptoms by day ten. PMID:27247810

  14. CULTIVO EXPERIMENTAL DEL CLADOCERO Moina sp ALIMENTADO CON Ankistrodesmus sp y Saccharomyces cereviseae

    OpenAIRE

    Martha Prieto; Litia De la Cruz; Mario Morales

    2006-01-01

    Objetivo. Realizar un cultivo experimental de cladócero Moina sp alimentado con Ankistrodesmus sp y Saccharomyces cereviseae. Materiales y métodos. Fueron realizados cultivos experimentales de la cepa de cladóceros Moina sp en el laboratorio de Alimento Vivo de la Universidad de Córdoba, bajo condiciones controladas de temperatura (22oC), pH (7.6), intensidad lumínica (2000 lux) y aireación. Se emplearon dos dietas de alimento como tratamiento (Ankistrodesmus y Ankistrodesmus mas Saccharomyce...

  15. Assessment of Surfactant Protein A (SP-A dependent agglutination

    Directory of Open Access Journals (Sweden)

    Griese Matthias

    2010-11-01

    Full Text Available Abstract Background Monomers of the collectin surfactant associated protein-A (SP-A are arranged in trimers and higher oligomers. The state of oligomerization differs between individuals and likely affects SP-A's functional properties. SP-A can form aggregates together with other SP-A molecules. Here we report and assess a test system for the aggregate forming properties of SP-A in serum and broncho-alveolar lavage samples. Methods Anti-SP-A antibodies fixed to latex beads bound SP-A at its N-terminal end and allowed the interaction with other SP-A molecules in a given sample by their C-terminal carbohydrate recognition domain (CRD to agglutinate the beads to aggregates, which were quantified by light microscopy. Results SP-A aggregation was dependent on its concentration, the presence of calcium, and was dose-dependently inhibited by mannose. Unaffected by the presence of SP-D no aggregation was observed in absence of SP-A. The more complex the oligomeric structure of SP-A present in a particular sample, the better was its capability to induce aggregation at a given total concentration of SP-A. SP-A in serum agglutinated independently of the pulmonary disease; in contrast SP-A in lung lavage fluid was clearly inferior in patients with chronic bronchitis and particularly with cystic fibrosis compared to controls. Conclusions The functional status of SP-A with respect to its aggregating properties in serum and lavage samples can be easily assessed. SP-A in lung lavage fluid in patients with severe neutrophilic bronchitis was inferior.

  16. Ovos de Toxocara sp. e larvas de Ancylostoma sp. em praça pública de Lavras, MG Toxocara sp. eggs and Ancylostoma sp. larva in public parks, Brazil

    Directory of Open Access Journals (Sweden)

    Antônio Marcos Guimarães

    2005-04-01

    Full Text Available Larva migrans visceral e cutânea são zoonoses parasitárias causadas pela infecção da larva de Toxocara sp. e Ancylostoma sp., respectivamente. O objetivo do estudo foi verificar a contaminação por ovos de Toxocara sp. e ovos e larvas de Ancylostoma sp. em amostras de solos coletadas de praças públicas e de áreas de recreação infantil de Lavras, Estado de Minas Gerais, por meio da técnica de centrífugo-flutuação e do método de Baermann. A ocorrência de ovos de Toxocara sp. e, ovos e larvas de Ancylostoma sp. foi observada em 69,6% (16/23 das amostras de solo coletadas de praças públicas. A contaminação somente por ovos de Ancylostoma sp. em amostras de solo coletadas em escolas/creches foi de 22,2% (4/18. A percentagem de amostras de areia coletadas de escolas/creches contaminadas somente com larvas de Ancylostoma sp. foi de 11,1% (2/18. Praças públicas são as áreas com maior risco potencial de infecção por Toxocara sp. e Ancylostoma sp. Exame coproparasitológico realizado em 174 amostras de fezes de cães observou 58% e 23%, respectivamente, com ovos de Ancylostoma sp. e Toxocara sp.Visceral and cutaneous larva migrans are parasitic zoonoses caused by the infection of larval nematodes Toxocara sp. and Ancylostoma sp. respectively. The objective of this study was to investigate the contamination by Toxocara sp. eggs and Ancylostoma sp. eggs and larva of soil samples collected from public parks and children's playground areas in state of Minas Gerais, Brazil, using both Baermann's method and centrifugal flotation technique. Toxocara sp. and Ancylostoma sp. eggs were observed in soil samples collected from public squares in 17.4% (4/23 and 69.6 (16/23 respectively. In schools and child day care settings the contamination by Ancylostoma sp. larva in sand samples was 11.1% (2/18. Public parks are settings of more potential risk of Toxocara sp. eggs and Ancylostoma sp. infection. Stool parasitology testing of 174 stool

  17. Características agronômicas do trigo em função de Azospirillum brasilense, ácidos húmicos e nitrogênio em casa de vegetação

    Directory of Open Access Journals (Sweden)

    Luan F. O. S. Rodrigues

    2014-01-01

    Full Text Available Objetivou-se, neste estudo, verificar o efeito do uso combinado de Azospirillum brasilense, ácidos húmicos e diferentes doses de nitrogênio nas características agronômicas do trigo. Os experimentos foram instalados no dia 21 de maio de 2011 e a colheita foi procedida no dia 13 de setembro de 2011. O delineamento experimental adotado foi o de blocos casualizados em esquema fatorial 4 x 4, com quatro repetições. O primeiro fator se refere à combinação da estirpe Ab-V5 de A. brasilense com os ácidos húmicos, sendo utilizados os seguintes tratamentos: controle; Ab-V5; ácido húmico e Ab-V5+ácido húmico e o segundo fator se refere às doses de nitrogênio (0, 30, 60 e 90 kg ha-1 N. A maioria das variáveis em análise apresentou efeito linear positivo dos tratamentos em função da adubação nitrogenada sendo que apenas para a variável massa de cem grãos este efeito foi linear negativo. Não houve diferença significativa entre as variâncias, na produção de grãos. Pôde-se concluir que o uso combinado de Ab-V5 + ácido húmico promove principalmente a produção de matéria seca de folhas e não é responsivo à adubação nitrogenada para os demais componentes produtivos em estudo nem para a produtividade dos grãos.

  18. Modificacion del Valor Nutrimental de Acidos Grasos en Semilla de la Halofita Salicornia bigelovii Torr. con la Interaccion de Bacterias Promotoras del Crecimiento de Plantas (Azospirillum halopraeferens y Klebsiella pneumoniae

    Directory of Open Access Journals (Sweden)

    Edgar Omar Rueda Puente

    2005-01-01

    Full Text Available Una especie vegetal a gran escala se presenta como una alternativa para la producción de ácidos grasos esenciales en nutrición humana por lo que su composición de ácidos grasos cobra especial importancia. Salicornia bigelovii una halófita que se desarrolla en ambientes áridos y costeros como las del estado de Sonora y de la península de Baja California Sur, México, presenta ser una especie alternativa en la producción de aceites comestibles. La fijación de N2 por bacterias asociadas con raíces de Salicornia bigelovii y halófitas similares son una fuente importante de nitrógeno disponible en ecosistemas costeros. La inoculación de Klebsiella pneumoniae y Azospirillum halopraeferens fue evaluada durante el desarrollo vegetativo de Salicornia bigelovii bajo condiciones de campo en dos genotipos (genotipo silvestre y cv. SOS-10, afectando positivamente variables como peso, longitud de plantas, rendimientos de producción y características bioquímicas como proteína total, ceniza, y contenido de lípidos totales en semilla producida. Nuestros resultados sugieren que ambos genotipos de S. bigelovii, bajo las condiciones de campo empleadas, pueden ser mejorados con la aplicación de K. pneumoniae y A. halopraeferens, mostrando una utilidad potencial para productores agrícolas de zonas semiáridas costeras.

  19. Framework, The Physics of sp(2,R)

    CERN Document Server

    Hawthorn, Ian; Ussher, Matthew

    2015-01-01

    A mathematical framework for relativistic quantum field theory is constructed with natural symmetry $\\mathsf{so}(2,3)= \\mathsf{sp}(2,\\mathbb{ R})$. In this framework gravity and electromagnetism unify as aspects of the geometry. The source equation for gravity differs from Einstein's equation and permits behaviour that could explain dark matter.

  20. A new virginae butanolide from Streptomyces sp.

    Institute of Scientific and Technical Information of China (English)

    Xiang LI; Yi Nan ZHENG; Wen Han LIN; Isabel SATTLER

    2006-01-01

    A novel butanolide, named virginaebutanolide F (1), was isolated from the lyophilized culture broth of Streptomyces sp., along with a known compound virginaebutanolide C (2). Their structures including the stereochemistry were elucidated on the basis of extensive 1D and 2D NMR as well as HRESI-MS and CD spectroscopic analysis.

  1. Ocorrência de Giardia sp. e Cryptosporidium sp. em Leopardus weidii de vida livre Occurrence of Giardia sp. and Cryptosporidium sp. in Leopardus weidii of wild life

    Directory of Open Access Journals (Sweden)

    Camila Belmonte Oliveira

    2008-04-01

    Full Text Available Leopardus weiidi (gato-maracajá é um mamífero neotropical de ampla distribuição no Brasil. No município de Cachoeira do Sul, RS, um exemplar foi capturado para tratamento, quando se coletou uma amostra de fezes, que foi analisada pelo método de centrífugo-flutuação com sulfato de zinco para pesquisa de parasitos. Foi observada elevada infecção por cistos de Giardia sp. e oocistos de Cryptosporidium sp.. Com base nos resultados, conclui-se que L. weeidi é hospedeiro desses protozoários.Leopardus weiidi (gato-maracajá is a neo-tropical mammal with has a wide distribution in Brazil. In the municipality of Cachoeira do Sul, RS, a fecal sample from a specimen captured for treatment was collected and analyzed by the centrifugal-flotation method with zinc sulfate for research of parasites. A large number of cysts of Giardia sp. and oocysts of Cryptosporidium sp. was observed. The results indicate that L. weeidi is a host of these protozoa.

  2. Carbon sp chains in graphene nanoholes

    DEFF Research Database (Denmark)

    Castelli, Ivano Eligio; Ferri, Nicola; Onida, Giovanni;

    2012-01-01

    Nowadays sp carbon chains terminated by graphene or graphitic-like carbon are synthesized routinely in several nanotech labs. We propose an ab initio study of such carbon-only materials, by computing their structure and stability, as well as their electronic, vibrational and magnetic properties. We...

  3. Biosorption of uranium by Azolla, SP, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Ludmila C.; Alves, Eliakim G.; Marumo, Julio T., E-mail: lcvieira@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ferreira, Rafael V. de P., E-mail: rafael@itatijuca.com [Itatijuca Biotech, Sao Paulo, SP (Brazil); Canevesi, Rafael L.S.; Silva, Edson A., E-mail: edson.silva2@unioeste.br [Universidade Estadual do Oeste Parana (UNIOESTE), Toledo, PR (Brazil)

    2015-07-01

    Radioactive liquid waste needs special attention and requires suitable treatment before deposition. Among the potential technologies under development for the treatment of liquid radioactive wastes the biosorption has been highlighted by being an efficient and low cost technique. Biosorption process involves the exchange of ions contained in the biomass matrix by others present in solution. There are many biomasses that could be applied in treatment of radioactive wastes, for example, agricultural residues and macrophyte. The aim of this study is evaluate the ability of the Azolla sp., a floating aquatic plant, to absorb uranium in solution. Azolla sp. is a macrophyte that has been used to treat effluents containing heavy metals. The biosorption capacity of uranium by Azolla sp. was experimentally determined and modeled by isotherms. Experiments were performed to determine metal uptake, and then the solutions were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES). The isotherms applied to model the data was Langmuir, Freundlich, Sips Toth, Redlich Peternson, Two-Site-Langmuir, Radke Prausnitz to develop a technique for the treatment of radioactive liquid waste generated at the Nuclear and Energy Research Institute (IPEN-CNEN/SP), Brazil. (author)

  4. Surfactant proteins, SP-A and SP-D, in respiratory fungal infections: their role in the inflammatory response.

    Science.gov (United States)

    Carreto-Binaghi, Laura Elena; Aliouat, El Moukhtar; Taylor, Maria Lucia

    2016-01-01

    Pulmonary surfactant is a complex fluid that comprises phospholipids and four proteins (SP-A, SP-B, SP-C, and SP-D) with different biological functions. SP-B, SP-C, and SP-D are essential for the lungs' surface tension function and for the organization, stability and metabolism of lung parenchyma. SP-A and SP-D, which are also known as pulmonary collectins, have an important function in the host's lung immune response; they act as opsonins for different pathogens via a C-terminal carbohydrate recognition domain and enhance the attachment to phagocytic cells or show their own microbicidal activity by increasing the cellular membrane permeability. Interactions between the pulmonary collectins and bacteria or viruses have been extensively studied, but this is not the same for fungal pathogens. SP-A and SP-D bind glucan and mannose residues from fungal cell wall, but there is still a lack of information on their binding to other fungal carbohydrate residues. In addition, both their relation with immune cells for the clearance of these pathogens and the role of surfactant proteins' regulation during respiratory fungal infections remain unknown. Here we highlight the relevant findings associated with SP-A and SP-D in those respiratory mycoses where the fungal infective propagules reach the lungs by the airways. PMID:27250970

  5. Cultivation of Microalgae Chlorella sp. and Scenedesmus sp. as a Potentional Biofuel Feedstock

    Directory of Open Access Journals (Sweden)

    Prof. dr. Violeta Makareviciene

    2011-10-01

    Full Text Available The growth of two robust algae strains Chlorella sp. and Scenedesmus sp. growing in Lithuanian lakes was investigated with the aim to obtain optimum conditions for biomass cultivation for biofuel production in the Lithuanian environment. Samples were taken from different nitrogen sources and of different concentrations, with addition of various concentrations of CO2 and in the presence of salt. The best biomass productivity was achieved using urea as a nitrogen source or modified growing medium BG11 with decreased concentration of NaNO3. The positive impact on the growth of biomass was achieved by aeration with CO2 (especially with concentration of 24%. Additional research into the removal of pollutants, such inorganic salts of nitrogen and phosphorus and organic materials from wastewater using microalgae has revealed good possibilities of using both algae strains in wastewater treatment plants. A content of oil in Chlorella sp. and Scenedesmus sp. has suggested their potential use as biodiesel feedstock.

  6. Candida flosculorum sp. nov. and Candida floris sp. nov., two yeast species associated with tropical flowers.

    Science.gov (United States)

    Rosa, Carlos A; Pagnocca, Fernando C; Lachance, Marc-André; Ruivo, Carla C C; Medeiros, Adriana O; Pimentel, Mariana R C; Fontenelle, Julio C R; Martins, Rogério P

    2007-12-01

    Two ascomycetous yeast species, Candida flosculorum sp. nov. and Candida floris sp. nov., were isolated from tropical flowers and their associated insects. C. flosculorum was isolated from flower bracts of Heliconia velloziana and Heliconia episcopalis (Heliconiaceae) collected from two Atlantic rain forest sites in Brazil. C. floris was isolated from flowers of Ipomoea sp. (Convolvulaceae) growing on the banks of the river Paraguai in the pantanal ecosystem in Brazil and from an adult of the stingless bee Trigona sp. and a flower of Merremia quinquefolia (Convolvulaceae) in Costa Rica. C. flosculorum belongs to the Metschnikowiaceae clade and C. floris belongs to the Starmerella clade. The type strain of C. flosculorum is UFMG-JL13(T) (=CBS 10566(T)=NRRL Y-48258(T)) and the type strain of C. floris is UWO(PS) 00-226.2(T) (=CBS 10593(T)=NRRL Y-48255(T)).

  7. Candida flosculorum sp. nov. and Candida floris sp. nov., two yeast species associated with tropical flowers.

    Science.gov (United States)

    Rosa, Carlos A; Pagnocca, Fernando C; Lachance, Marc-André; Ruivo, Carla C C; Medeiros, Adriana O; Pimentel, Mariana R C; Fontenelle, Julio C R; Martins, Rogério P

    2007-12-01

    Two ascomycetous yeast species, Candida flosculorum sp. nov. and Candida floris sp. nov., were isolated from tropical flowers and their associated insects. C. flosculorum was isolated from flower bracts of Heliconia velloziana and Heliconia episcopalis (Heliconiaceae) collected from two Atlantic rain forest sites in Brazil. C. floris was isolated from flowers of Ipomoea sp. (Convolvulaceae) growing on the banks of the river Paraguai in the pantanal ecosystem in Brazil and from an adult of the stingless bee Trigona sp. and a flower of Merremia quinquefolia (Convolvulaceae) in Costa Rica. C. flosculorum belongs to the Metschnikowiaceae clade and C. floris belongs to the Starmerella clade. The type strain of C. flosculorum is UFMG-JL13(T) (=CBS 10566(T)=NRRL Y-48258(T)) and the type strain of C. floris is UWO(PS) 00-226.2(T) (=CBS 10593(T)=NRRL Y-48255(T)). PMID:18048759

  8. Biodegradation of hexavalent chromium (Cr+6) in wastewater using Pseudomonas sp. and Bacillus sp. bacterial strains

    OpenAIRE

    Muhammad Qasim

    2013-01-01

    The recovery of toxic metal compounds is a deep concern in all industries. Hexavalent chromium is particularly worrying because of its toxic influence on human health. In this paper, biodegradation of hexavalent chromium (Cr+6) present in wastewater has been studied using two different bacterial strains; Pseudomonas sp. and Bacillus sp. A chemostat (with and without recycle of cells) with 10 L liquid culture volume was used to study the substrate and the biomass cell concentrations with time....

  9. Effects of lung surfactant proteins, SP-B and SP-C, and palmitic acid on monolayer stability.

    OpenAIRE

    Ding, J; Takamoto, D Y; von Nahmen, A; Lipp, M M; Lee, K Y; Waring, A J; Zasadzinski, J A

    2001-01-01

    Langmuir isotherms and fluorescence and atomic force microscopy images of synthetic model lung surfactants were used to determine the influence of palmitic acid and synthetic peptides based on the surfactant-specific proteins SP-B and SP-C on the morphology and function of surfactant monolayers. Lung surfactant-specific protein SP-C and peptides based on SP-C eliminate the loss to the subphase of unsaturated lipids necessary for good adsorption and respreading by inducing a transition between...

  10. Microbiologically influenced corrosion of galvanized steel by Desulfovibrio sp. and Desulfosporosinus sp. in the presence of Ag–Cu ions

    Energy Technology Data Exchange (ETDEWEB)

    Ilhan-Sungur, Esra, E-mail: esungur@istanbul.edu.tr [Istanbul University, Faculty of Science, Department of Biology, 34134 Vezneciler, Istanbul (Turkey); Unsal-Istek, Tuba [Istanbul University, Faculty of Science, Department of Biology, 34134 Vezneciler, Istanbul (Turkey); Cansever, Nurhan [Yıldız Technical University, Faculty of Chemistry-Metallurgy, Metallurgical and Materials Engineering Department, 34210 Esenler, Istanbul (Turkey)

    2015-07-15

    The effects of Ag–Cu ions on the microbiologically induced corrosion of galvanized steel in the presence of Desulfovibrio sp. and Desulfosporosinus sp. were investigated. The corrosion behavior of galvanized steel was analyzed by potentiodynamic polarization and electrochemical impedance spectroscopy. The biofilm, corrosion products and Ag–Cu ions on the surfaces were investigated by using scanning electron microscopy, energy dispersive X-ray spectrometry and elemental mapping. The biofilm layer formed by the Desulfovibrio sp. was stable covering the all surface of galvanized steel coupons, while that by Desulfosporosinus sp. was intermittent, highly porous and heterogeneous. It was found that both of the sulfate reducing bacteria species accelerated corrosion of the galvanized steel. However, it was detected that Desulfosporosinus sp. was more corrosive for galvanized steel than Desulfovibrio sp. Scanning electron microscopy images showed that Desulfovibrio sp. and Desulfosporosinus sp. in biofilm clustered into patches on the galvanized steel surface when the culture contained toxic Ag–Cu ions. The ions affected the growth of the sulfate reducing bacteria strains in different ways and hence the corrosion behaviors. It was observed that the Ag–Cu ions affected negatively growth of Desulfosporosinus sp. especially after 24 h of exposure leading to a decrease in the corrosion rate of galvanized steel. However, Desulfovibrio sp. showed more corrosive effect in the presence of the ions according to the ions-free culture. Energy dispersive X-ray spectrometry analysis showed that corrosion products on the surfaces were mainly composed of Zn, S, Na, O and P. - Highlights: • Galvanized steel was corroded by Desulfosporosinus sp. and Desulfovibrio sp. • Desulfosporosinus sp. is more corrosive than Desulfovibrio sp. • The Ag–Cu ions affected corrosion behavior of Desulfosporosinus sp. and Desulfovibrio sp. on galvanized steel.

  11. Interaction of Sp1 zinc finger with transport factor in the nuclear localization of transcription factor Sp1

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Tatsuo [Department of Medicinal Biotechnology, Institute for Medicinal Research, Graduate School of Pharmaceutical Sciences, The University of Tokushima, 1-78 Sho-machi, Tokushima 770-8505 (Japan); Kitamura, Haruka; Uwatoko, Chisana; Azumano, Makiko [Department of Molecular Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Doshisha Women' s University, Kodo, Kyotanabe City, Kyoto 610-0395 (Japan); Itoh, Kohji, E-mail: kitoh@ph.tokushima-u.ac.jp [Department of Medicinal Biotechnology, Institute for Medicinal Research, Graduate School of Pharmaceutical Sciences, The University of Tokushima, 1-78 Sho-machi, Tokushima 770-8505 (Japan); Kuwahara, Jun, E-mail: jkuwahar@dwc.doshisha.ac.jp [Department of Molecular Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Doshisha Women' s University, Kodo, Kyotanabe City, Kyoto 610-0395 (Japan)

    2010-12-10

    Research highlights: {yields} Sp1 zinc fingers themselves interact with importin {alpha}. {yields} Sp1 zinc finger domains play an essential role as a nuclear localization signal. {yields} Sp1 can be transported into the nucleus in an importin-dependent manner. -- Abstract: Transcription factor Sp1 is localized in the nucleus and regulates the expression of many cellular genes, but the nuclear transport mechanism of Sp1 is not well understood. In this study, we revealed that GST-fused Sp1 protein bound to endogenous importin {alpha} in HeLa cells via the Sp1 zinc finger domains, which comprise the DNA binding domain of Sp1. It was found that the Sp1 zinc finger domains directly interacted with a wide range of importin {alpha} including the armadillo (arm) repeat domain and the C-terminal acidic domain. Furthermore, it turned out that all three zinc fingers of Sp1 are essential for binding to importin {alpha}. Taken together, these results suggest that the Sp1 zinc finger domains play an essential role as a NLS and Sp1 can be transported into the nucleus in an importin-dependent manner even though it possesses no classical NLSs.

  12. Fitoremediasi limbah budidaya sidat menggunakan filamentous algae (Spirogyra sp.

    Directory of Open Access Journals (Sweden)

    Tri Apriadi

    2014-09-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui potensi dari filamentous algae (Spirogyra sp. sebagai agen bioremediasi dalam mereduksi kandungan bahan organik limbah budidaya sidat. Penelitian menggunakan rancangan acak lengkap dengan perlakuan perbedaan dosis limbah (25 %, 50 %, 75 %, 100%. Wadah penelitian berupa akuarium resirkulasi menggunakan sistem carrousel. Dilakukan pengukuran secara rutin terhadap beberapa parameter kualitas air serta perubahan bobot Spirogyra sp. selama dua minggu retensi. Diperoleh hasil bahwa penurunan konsentrasi bahan organik menggunakan Spirogyra sp. berlangsung efektif hingga hari keenam. Spirogyra sp. mampu mentolelir limbah budidaya sidat pada dosis limbah 25% dan 50%. Spirogyra sp. pada perlakuan dosis limbah 50% memiliki kemampuan yang lebih baik dalam menurunkan bahan organik limbah budidaya sidat.

  13. Sp6 and Sp8 transcription factors control AER formation and dorsal-ventral patterning in limb development.

    Directory of Open Access Journals (Sweden)

    Endika Haro

    2014-08-01

    Full Text Available The formation and maintenance of the apical ectodermal ridge (AER is critical for the outgrowth and patterning of the vertebrate limb. The induction of the AER is a complex process that relies on integrated interactions among the Fgf, Wnt, and Bmp signaling pathways that operate within the ectoderm and between the ectoderm and the mesoderm of the early limb bud. The transcription factors Sp6 and Sp8 are expressed in the limb ectoderm and AER during limb development. Sp6 mutant mice display a mild syndactyly phenotype while Sp8 mutants exhibit severe limb truncations. Both mutants show defects in AER maturation and in dorsal-ventral patterning. To gain further insights into the role Sp6 and Sp8 play in limb development, we have produced mice lacking both Sp6 and Sp8 activity in the limb ectoderm. Remarkably, the elimination or significant reduction in Sp6;Sp8 gene dosage leads to tetra-amelia; initial budding occurs, but neither Fgf8 nor En1 are activated. Mutants bearing a single functional allele of Sp8 (Sp6-/-;Sp8+/- exhibit a split-hand/foot malformation phenotype with double dorsal digit tips probably due to an irregular and immature AER that is not maintained in the center of the bud and on the abnormal expansion of Wnt7a expression to the ventral ectoderm. Our data are compatible with Sp6 and Sp8 working together and in a dose-dependent manner as indispensable mediators of Wnt/βcatenin and Bmp signaling in the limb ectoderm. We suggest that the function of these factors links proximal-distal and dorsal-ventral patterning.

  14. Analysis list: SP2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available SP2 Blood,Liver,Pluripotent stem cell + hg19 http://dbarchive.biosciencedbc.jp/kyus...hu-u/hg19/target/SP2.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/SP2.5.tsv http://dbarchive.bioscien...cedbc.jp/kyushu-u/hg19/target/SP2.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/SP2.B...lood.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/SP2.Liver.tsv,http://dbarchive.bioscien...cedbc.jp/kyushu-u/hg19/colo/SP2.Pluripotent_stem_cell.tsv http://dbarchive.biosciencedbc

  15. Taxonomy Icon Data: Synechocystis sp.PCC 6803 [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Synechocystis_sp_PCC_6803_NL.png Synechocystis_sp_PCC_6803_S.png Synechocystis_sp_PCC_6803_NS.png http://biosciencedbc.jp/taxonomy..._icon/icon.cgi?i=Synechocystis+sp%2ePCC+6803&t=L http://biosciencedbc.jp/taxonomy_ico...n/icon.cgi?i=Synechocystis+sp%2ePCC+6803&t=NL http://biosciencedbc.jp/taxonomy_ic...on/icon.cgi?i=Synechocystis+sp%2ePCC+6803&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Synechocystis...+sp%2ePCC+6803&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=69 ...

  16. Spøgelsets egne ord

    DEFF Research Database (Denmark)

    Gemzøe, Anker

    2012-01-01

    refleksioner over den gengangerscene, der åbner Shakespeares Hamlet. Ifølge Derridas ’hantologie’ opererer spøgelser i en eksistentiel tidslighed, der har at gøre med sorg, sprog og forvandling. Genremæssigt, tilføjer Gemzøe, har gengangeren det med at husere i tragedien. Med Derridas ’hantologie’ som en af de...

  17. Uptake of Glyphosate by an Arthrobacter sp

    OpenAIRE

    Pipke, Rüdiger; Schulz, Arno; Amrhein, Nikolaus

    1987-01-01

    The uptake of glyphosate (N-[phosphonomethyl]glycine) by an Arthrobacter sp. which can utilize this herbicide as its sole source of phosphorus was investigated. Orthophosphate suppressed the expression of the uptake system for glyphosate and also competed with glyphosate for uptake. The Km for glyphosate uptake was 125 μM, and the Ki for orthophosphate was 24 μM. Organophosphonates as well as organophosphates inhibited glyphosate uptake, but only organophosphates and orthophosphate suppressed...

  18. Phenotypic variation in Blastocystis sp. ST3

    OpenAIRE

    Ragavan, Nanthiney Devi; Govind, Suresh Kumar; Chye, Tan Tian; Mahadeva, Sanjiv

    2014-01-01

    Background Blastocystis, is one of the most common human intestinal protozoan, which has many conflicting reports on its pathogenic role. Gut conditions which obviously varies in asymptomatic individuals, symptomatic and irritable bowel syndrome (IBS) patients in terms of gut flora, pH, osmotic pressure and water potentials could play an important role in its pathogenicity. The present study is the first study to investigate phenotypic characteristics of Blastocystis sp. ST3 isolated from asy...

  19. Blastocystis sp. from food animals in India

    OpenAIRE

    Sreekumar, C.; Selvaraj, J.; Gomathinayagam, S.; Thangapandiyan, M.; Ravikumar, G.; Roy, Parimal; C Balachandran

    2013-01-01

    Blastocystis, a zoonotic protozoan found in the intestinal tracts of a wide range of animals, has not been reported from non-human hosts from India so far. Organisms indistinguishable from Blastocystis sp. were identified in the Giemsa stained intestinal scrapings collected from carcasses of piglet and poultry that were brought for necropsy to the Central University Laboratory, Chennai. The ‘central vacuole forms’ of the parasite, with number of nuclei ranging from 1 to 12 were identified. Th...

  20. Biosorption of 241Am by Candida sp

    International Nuclear Information System (INIS)

    The biosorption of radionuclide 241Am from solutions by Candida sp., and the influences of experimental conditions on the adsorption were studied. The results showed that the adsorption equilibrium was achieved within 4h and the optimum pH=2. No significant differences on 241Am biosorption were observed at 10-45 degree C, or challenged with Au3+ or Ag+, even 1500 times or 4500 times over 241Am, respectively. The adsorption rate could reach 97.8% by dry Candida sp. of 0.82 g/L in 241Am solutions (pH=2) of 5.6-111 MBq/L (44.04-873.0 μg/L) (C0), with maximum adsorption capacity (W) of 63.5 MBq/g (501.8 μg/g), implying that the removal of 241Am by Candida sp. from solutions was feasible. The relationship between activities (C0) and adsorption capacities (W) of 241Am indicated that the biosorption process could be described by Langmuir adsorption isotherm

  1. Det digitale spøgelse

    DEFF Research Database (Denmark)

    Hansen, Ejvind

    2008-01-01

    man opgive at søge ind til én kernebetydning, som kan kommunikeres neutralt gennem forskellige medier. Sætningen “Du er sød” betyder altså noget forskelligt alt efter, om den skrives i et brev, aftegnes på himlen med et fly eller sendes i en e-mail. Og der er ikke én af disse gengivelser, der kan...... påberåbe sig at være den rigtige kernebetydning. Spørgsmålet, der altid kan rejses, er nemlig: Hvad skulle være begrundelsen for at betragte ét medie som værende nærmere kernen end de andre? Man kunne selvfølgelig hævde, at der findes en abstrakt betydning, som ikke kan gengives med noget medie, men som...... til forståelse med den. Omdrejningspunktet er et spøgelse! Artiklens ærinde er at udpege et par af de spøgelser som udspringer af den kommunikation, der udspringer af internettet. Jeg går særligt i klinch med overdrevne forestillinger om internettets effektivitet....

  2. Sarcocystis sp. encephalomyelitis in a cat.

    Science.gov (United States)

    Bisby, Tricia M; Holman, Patricia J; Pitoc, George A; Packer, Rebecca A; Thompson, Craig A; Raskin, Rose E

    2010-03-01

    A 5-month-old male neutered domestic shorthair cat was evaluated for spinal pain, ataxia, and anisocoria. Neuroanatomic localization indicated diffuse or multifocal central nervous system disease. On cerebrospinal fluid analysis, neutrophilic pleocytosis and intracellular protozoal merozoites were observed. The merozoites were oval, 2-4 microm in width and 4-6 microm in length, and had linear arrays of nuclear material concentrated at one pole. Serum was positive for Sarcocystis sp. antibodies and negative for Toxoplasma gondii antibodies. The organism was determined to be either Sarcocystis neurona or Sarcocystis dasypi based on sequence analysis of the internal transcribed spacer 1 ribosomal RNA genomic region. Clinical disease resolved following treatment with 3 different protocols for protozoal infection. This case is the first to demonstrate the antemortem diagnosis and survival of a domestic cat with Sarcocystis sp.-associated encephalomyelitis. Clinicians and cytopathologists should include Sarcocystis sp. as a differential for feline inflammatory central nervous system disease characterized by neutrophilic pleocytosis. PMID:19548967

  3. Sterols from the Madagascar Sponge Fascaplysinopsis sp.

    Directory of Open Access Journals (Sweden)

    Yoel Kashman

    2010-12-01

    Full Text Available The sponge Fascaplysinopsis sp. (order Dictyoceratida, Family Thorectidae from the west coast of Madagascar (Indian Ocean is a particularly rich source of bioactive nitrogenous macrolides. The previous studies on this organism led to the suggestion that the latter should originate from associated microsymbionts. In order to evaluate the influence of microsymbionts on lipid content, 10 samples of Fascaplysinopsis sp. were investigated for their sterol composition. Contrary to the secondary metabolites, the sterol patterns established were qualitatively and quantitatively stable: 14 sterols with different unsaturated nuclei, D5, D7 and D5,7, were identified; the last ones being the main sterols of the investigated sponges. The chemotaxonomic significance of these results for the order Dictyoceratida is also discussed in the context of the literature. The conjugated diene system in D5,7 sterols is known to be unstable and easily photo-oxidized during storage and/or experiments to produce 5a,8a-epidioxy sterols. However, in this study, no 5a,8a-epidioxysterols (or only trace amounts were observed. Thus, it was supposed that photo-oxidation was avoided thanks to the natural antioxidants detected in Fascaplysinopsis sp. by both the DPPH and b-caroten bleaching assays.

  4. Bioremediation of hexavalent chromate using permeabilized Brevibacterium sp. and Stenotrophomonas sp. cells.

    Science.gov (United States)

    Ge, Shimei; Ge, Shichao; Zhou, Maohong; Dong, Xinjiao

    2015-07-01

    Bioremediation has been found to be a useful method for removing hexavalent chromium (Cr(VI)), which is very toxic, from wastewater. Two strains of bacteria that were able to reduce Cr(VI) effectively were isolated from Cr(VI) contaminated soil samples and identified as Brevibacterium sp. K1 and Stenotrophomonas sp. D6, respectively, based on 16S rRNA gene sequence analyses. Brevibacterium sp. K1 and Stenotrophomonas sp. D6 could grow in Luria-Broth medium containing K2Cr2O7 at 1000 and 1600 mg/L, respectively, and they completely reduced the Cr(VI) in LB medium containing K2Cr2O7 at 200 mg/L within 72 h. Further analyses revealed that permeabilized K1 and D6 cells reduced Cr(VI) more effectively than did the resting cells. Triton X-100 was the best permeabilizing agent that was tested. The permeabilized cells of both strains could completely reduce Cr(VI) in industrial wastewater twice before needing to be replenished. The results suggested that these chromate-reducing bacteria are potential candidates for practical use biotreating industrial effluents containing Cr(VI) with Stenotrophomonas sp. D6 being the more effective bacterium. PMID:25881152

  5. EFEKTIFITAS DAYA HAMBAT BAKTERI Streptomyces sp TERHADAP Erwinia sp PENYEBAB PENYAKIT BUSUK REBAH PADA TANAMAN LIDAH BUAYA (Aloe barbadensis Mill

    Directory of Open Access Journals (Sweden)

    SARMILA TASNIM

    2013-05-01

    Full Text Available Streptomyces sp was conducted from December 2010 - June 2011 at the Laboratoryof Microbiology, Biology Department, Math and Science Faculty, UdayanaUniversity Bukit Jimbaran-Bali. Implementation stages of the research consisted ofisolation and testing of the antibiotic activity Streptomyces sp to inhibit growthbacterial pathogens Erwinia sp as a cause of disease in plants fallen foul (Soft rot ofAloe barbadensis Mill.The results of this study have eight isolates of Streptomyces spwith macroscopic and microscopic characters are varied. Furthermore, all isolateswere obtained and then tested against antibiotic activity to inhibit growth the bacteriaErwinia sp. Test results obtained by Streptomyces sp that has the most effective ininhibiting the ability of the bacteria Erwinia sp isolates are Streptomyces sp2for (45%.

  6. Aspectos morfofisiológicos de plantas de milho e bioquímico do solo em resposta à adubação nitrogenada e à inoculação com Azospirillum brasilense

    Directory of Open Access Journals (Sweden)

    Tâmara Prado de Morais

    2015-12-01

    Full Text Available RESUMO O nitrogênio (N é um macronutriente que aumenta a produção de grãos na cultura do milho e o seu manejo adequado torna-se indispensável como proposta de uma agricultura sustentável, incluindo o uso de fontes alternativas como bactérias fixadoras de N2. Os objetivos deste trabalho foram avaliar a resposta morfofisiológica de plantas de milho e a atividade de enzimas no solo (urease e fosfatase decorrente da adubação N mineral e da inoculação com Azospirillum brasilense. Dois ensaios foram realizados em condições de casa de vegetação com solo de cerrado. O delineamento estatístico adotado foi o de blocos ao acaso com os tratamentos distribuídos em esquema fatorial 3 x 3, sendo o primeiro fator correspondente a doses de N (0; 100 e 200 kg ha-1 e o segundo, a doses de um inoculante líquido à base de A. brasilense aplicado via sementes (0; 100 e 200 mL ha-1. Ao final desse experimento, outro ensaio foi realizado para verificar o possível efeito residual da inoculação e da adubação nitrogenada. A adição de fertilizantes nitrogenados promoveu maior desenvolvimento das plantas de milho, elevou os teores de clorofila e de nutrientes. Houve aumento da atividade das enzimas relacionadas à disponibilização de amônio e fósforo inorgânico na rizosfera. Além disso, o nitrogênio apresentou efeito residual no desenvolvimento das plantas na semeadura subsequente. A dose de 200 mL ha-1 de A. brasilense associada à dose de 200 kg ha-1 de N aumentou a resposta fisiológica da cultura.

  7. Antibacterial Activity of Freshwater Microalga Scenedesmus sp. on Foodborne Pathogens Staphylococcus aureus and Salmonella sp.

    Directory of Open Access Journals (Sweden)

    Aisha Gogoba Ishaq

    2016-01-01

    Full Text Available Microalgae possess promising bioactive compounds with a wide range of activities. In this study, crude pigment extract of Scenedesmus sp. a freshwater microalga was screened against two known foodborne pathogens Staphylococcus aureus (ATCC 25923 and Salmonella sp. (ATCC 14028 to evaluate its antimicrobial properties. The crude pigment of the microalga was extracted with 90 % acetone whereas antibacterial screening was done by agar well diffusion method. In addition, the MIC of crude pigment was determined following the macrobroth dilution method. Concentrations ranging from 0.35mg/ml – 3.48 mg/ml demonstrated highest inhibitory activity against Staphylococcus aureus (ATCC 25923.  The MIC was achieved at 0.08 mg/ ml. On the other hand, there was no inhibitory activity at any concentration of crude extract against Salmonella sp. (ATCC 14028.  Results of this study suggest that the inhibitory activity may be limited to gram positive foodborne pathogen Staphylococcus aureus.

  8. Direct transesterification of Oedogonium sp. oil be using immobilized isolated novel Bacillus sp. lipase.

    Science.gov (United States)

    Sivaramakrishnan, Ramachandran; Muthukumar, Karuppan

    2014-01-01

    This work emphasizes the potential of the isolated Bacillus sp. lipase for the production of fatty acid methyl ester by the direct transesterification of Oedogonium sp. of macroalgae. Dimethyl carbonate was used as the extraction solvent and also as the reactant. The effect of solvent/algae ratio, water addition, catalyst, temperature, stirring and time on the direct transesterification was studied. The highest fatty acid methyl ester yield obtained under optimum conditions (5 g Oedogonium sp. powder, 7.5 ml of solvent (dimethyl carbonate)/g of algae, 8% catalyst (%wt/wt of oil), distilled water 1% (wt/wt of algae), 36 h, 55°C and 180 rpm) was 82%. Final product was subjected to thermogravimetric analysis and (1)H NMR analysis. The results showed that the isolated enzyme has good potential in catalyzing the direct transesterification of algae, and the dimethyl carbonate did not affect the activity of the isolated lipase. PMID:23890544

  9. Isolation of C11 Cyclopentenones from Two Didemnid Species, Lissoclinum sp. and Diplosoma sp.

    Directory of Open Access Journals (Sweden)

    Katsuhiro Ueda

    2009-12-01

    Full Text Available A series of new C11 cyclopentenones 1-7 was isolated, together with four known metabolites 9/10, 12 and 13, from the extract of the didemnid ascidian Lissoclinum sp. The other didemnid ascidian Diplosoma sp. contained didemnenones 1, 2 and 5, and five known metabolites 8-12. The structures of 1-7 were elucidated by spectroscopic analyses. Cytotoxicity of the isolated compounds was evaluated against three human cancer cell lines (HCT116, A431 and A549.

  10. Characterization of a Bioflocculant Produced by a Consortium of Halomonas sp. Okoh and Micrococcus sp. Leo

    OpenAIRE

    Okoh, Anthony I; Mabinya, Leonard V.; Kunle Okaiyeto; Nwodo, Uchechukwu U

    2013-01-01

    The physicochemical and flocculating properties of a bioflocculant produced by a bacterial consortium composed of Halomonas sp. Okoh and Micrococcus sp. Leo were investigated. The purified bioflocculant was cation and pH dependent, and optimally flocculated kaolin clay suspension at a dosage of 0.1 mg/mL. The flocculating activity of the bioflocculant was stimulated in the presence of Ca2+, Mn2+, Al3+ and had a wide pH range of 2–10, with the highest flocculating activity of 86% at pH 8. The ...

  11. Two-Dimensional Phosphorus Carbide: Competition between sp(2) and sp(3) Bonding.

    Science.gov (United States)

    Guan, Jie; Liu, Dan; Zhu, Zhen; Tománek, David

    2016-05-11

    We propose previously unknown allotropes of phosphorus carbide (PC) in the stable shape of an atomically thin layer. Different stable geometries, which result from the competition between sp(2) bonding found in graphitic C and sp(3) bonding found in black P, may be mapped onto 2D tiling patterns that simplify categorizing of the structures. Depending on the category, we identify 2D-PC structures that can be metallic, semimetallic with an anisotropic Dirac cone, or direct-gap semiconductors with their gap tunable by in-layer strain.

  12. Streptomyces sp. Sebagai Biofungisida Patogen Fusarium oxysporum (Schlecht.) f.sp. lycopersici (Sacc.) Snyd. et Hans. Penyebab Penyakit Layu Pada Tanaman Tomat (Solanum lycopersicum L.)

    OpenAIRE

    NURI MANDAN SARI; RETNO KAWURI; KHAMDAN KHALIMI

    2014-01-01

    A research was conducted to isolate Streptomyces sp. of soil Udayana University campus in theBukit-Jimbaran, to obtain the most effective Streptomyces sp. which is effective in inhibit the growth ofFusarium oxysporum f.sp. lycopersici, and to test response of tomato plants with Streptomyces sp.culture against Fusarium wilt desease. Implementation phases of the research consisted of isolation andidentification of Streptomyces sp, test the inhibition against F. oxysporum f.sp. lycopersici, and ...

  13. Infant formula alters surfactant protein A (SP-A) and SP-B expression in pulmonary epithelial cells.

    Science.gov (United States)

    Chen, Maurice G; Atkins, Constance L; Bruce, Shirley R; Khan, Amir M; Liu, Yuying; Alcorn, Joseph L

    2011-09-01

    Surfactant proteins A (SP-A) and SP-B are critical in the ability of pulmonary surfactant to reduce alveolar surface tension and provide innate immunity. Aspiration of infant milk formula can lead to lung dysfunction, but direct effects of aspirated formula on surfactant protein expression in pulmonary cells have not been described. The hypothesis that infant formula alters surfactant protein homeostasis was tested in vitro by assessing surfactant protein gene expression in cultured pulmonary epithelial cell lines expressing SP-A and SP-B that were transiently exposed (6 hr) to infant formula. Steady-state levels of SP-A protein and mRNA and SP-B mRNA in human bronchiolar (NCI-H441) and mouse alveolar (MLE15) epithelial cells were reduced in a dose-dependent manner 18 hr after exposure to infant formula. SP-A mRNA levels remained reduced 42 hr after exposure, but SP-B mRNA levels increased 10-fold. Neither soy formula nor non-fat dry milk affected steady-state SP-A and SP-B mRNA levels; suggesting a role of a component of infant formula derived from cow milk. These results indicate that infant formula has a direct, dose-dependent effect to reduce surfactant protein gene expression. Ultimately, milk aspiration may potentially result in a reduced capacity of the lung to defend against environmental insults. PMID:21520433

  14. O-GlcNAc modification of Sp3 and Sp4 transcription factors negatively regulates their transcriptional activities.

    Science.gov (United States)

    Ha, Changhoon; Lim, Kihong

    2015-11-13

    The addition of O-linked N-acetylglucosamine (O-GlcNAc) on serine or threonine modifies a myriad of proteins and regulates their function, stability and localization. O-GlcNAc modification is common among chromosome-associated proteins, such as transcription factors, suggesting its extensive involvement in gene expression regulation. In this study, we demonstrate the O-GlcNAc status of the Sp family members of transcription factors and the functional impact on their transcriptional activities. We highlight the presence of O-GlcNAc residues in Sp3 and Sp4, but not Sp2, as demonstrated by their enrichment in GlcNAc positive protein fractions and by detection of O-GlcNAc residues on Sp3 and Sp4 co-expressed in Escherichia coli together with O-GlcNAc transferase (OGT) using an O-GlcNAc-specific antibody. Deletion mutants of Sp3 and Sp4 indicate that the majority of O-GlcNAc sites reside in their N-terminal transactivation domain. Overall, using reporter gene assays and co-immunoprecipitations, we demonstrate a functional inhibitory role of O-GlcNAc modifications in Sp3 and Sp4 transcription factors. Thereby, our study strengthens the current notion that O-GlcNAc modification is an important regulator of protein interactome.

  15. Early SP-100 flight mission designs

    Science.gov (United States)

    Josloff, Allan T.; Shepard, Neal F.; Kirpich, Aaron S.; Murata, Ronald; Smith, Michael A.; Stephen, James D.

    1993-01-01

    Early flight mission objectives can be met with a Space Reactor Power System (SRPS) using thermoelectric conversion in conjunction with fast spectrum, lithium-cooled reactors. This paper describes two system design options using thermoelectric technology to accommodate an early launch. In the first of these options, radiatively coupled Radioiosotope Thermoelectric Generator (RTG) unicouples are adapted for use with a SP-100-type reactor heat source. Unicouples have been widely used as the conversion technology in RTGs and have demonstrated the long-life characteristics necessary for a highly relible SRPS. The thermoelectric leg height is optimized in conjunction with the heat rejection temperature to provide a mass optimum 6-kWe system configured for launch on a Delta II launch vehicle. The flight-demonstrated status of this conversion technology provides a high confidence that such a system can be designed, assembled, tested, and launched by 1997. The use of a SP-100-type reactor assures compliance with safety requirements and expedites the flight safety approval process while, at the same time, providing flight performance verification for a heat source technology with the growth potential to meet future national needs for higher power levels. A 15-kW2, Atlas IIAS-launched system using the compact, conductively coupled multicouple converters being developed under the SP-100 program to support an early flight system launch also described. Both design concepts have been scaled to 20-kWe in order to support recent studies by DOE/NASA for higher power early launch missions.

  16. Occurrence of Salmonella sp in laying hens

    Directory of Open Access Journals (Sweden)

    Gama NMSQ

    2003-01-01

    Full Text Available This study was carried out to investigate the presence of Salmonella sp in flocks of white laying hens. In different farms, the transport boxes of twelve flocks were inspected at arrival for the presence of Salmonella. Four positive (A, B, L and M and one negative (I flocks were monitored at each four weeks using bacteriological examination of cecal fresh feces up to 52 weeks. Birds were also evaluated at 52 weeks, when 500 eggs were taken randomly, and at 76 weeks, after forced molt. Salmonella enterica serovar Enteritidis and S. enterica rough strain were isolated from the transport boxes of the four positive flocks (flocks A, B, L and M. Salmonella sp was not isolated from the transport boxes or from the feces after 76 weeks-old in flock I. Salmonella sp was isolated in the 1st, 11th, 34th, 42nd and 76th weeks from flock A; in the 1st, 4th, 11th and 76th weeks from flock B; in the first week and in the 17th to 52nd weeks from flock L; and in the 1st and 76th weeks from flock M. S. Enteritidis, S. enterica rough strain and Salmonella enterica serovar Infantis were isolated from the four positive flocks. Besides, Salmonella enterica serovar Javiana was isolated from flocks B and L, and Salmonella enterica serovar Mbandaka was isolated from flock L. Eggs produced by flock A and by flock L were contaminated with S. Enteritidis and S. enterica rough strain. According to these results, Salmonella-infected flocks may produce contaminated eggs.

  17. Equity valuation : Pirelli & C. SpA

    OpenAIRE

    Bernardino, André Rolhas

    2015-01-01

    This thesis has the purpose to value Pirelli & C. SpA at 31st of December of 2014. Pirelli is publicly traded in the Milan Stock Exchange, Borsa Italiana, and it is known as the fifth largest tyre manufacturer in the world with a great focus on high-end premium tyres. To valuate Pirelli’s equity a discounted cash flow methodology is used with an outcome of a 14,39 Euros price per share. To complete the valuation it is put in place a relative valuation, which supports the author’s recommendati...

  18. Occurrence of Salmonella sp in laying hens

    OpenAIRE

    Gama NMSQ; Berchieri Jr A; SA Fernandes

    2003-01-01

    This study was carried out to investigate the presence of Salmonella sp in flocks of white laying hens. In different farms, the transport boxes of twelve flocks were inspected at arrival for the presence of Salmonella. Four positive (A, B, L and M) and one negative (I) flocks were monitored at each four weeks using bacteriological examination of cecal fresh feces up to 52 weeks. Birds were also evaluated at 52 weeks, when 500 eggs were taken randomly, and at 76 weeks, after forced molt. Salmo...

  19. Metabolites from mangrove endophytic fungus Dothiorella sp.

    Institute of Scientific and Technical Information of China (English)

    XUQingyan; WANGJianfeng; HUANGYaojian; ZHENGZhonghui; SONGSiyang; ZHANGYongmin; SUWenjin

    2004-01-01

    Mangroves are special woody plant communities in the intertidal zone of tropical and subtropical coasts. They prove to be a natural microorganisms and new metabolites storage. In the study of mangrove endophytic fungi metabolites, four new compounds, Compounds 1, 2, 3 and 4, as well as a known octaketide, cytosporone B (5), are isolated from an endophytic fungus, Dothiorella sp., HTF3. They all show cytotoxic activities. The elucidation of these structures is mainly based on 1D/2D NMR and ESI-MS spectral analyses.

  20. Uranium accumulation by Pseudomonas sp. EPS-5028

    International Nuclear Information System (INIS)

    Pseudomonas sp. EPS-5028 was examined for the ability to accumulate uranium from solutions. The uptake of uranium by this microorganism is very rapid and is affected by pH but not by temperature, metabolic inhibitors, culture time and the presence of various cations and anions. The amount of uranium absorbed by the cells increased as the uranium concentration of the solution increased up to 55 mg uranium/g cell dry weight. Electron microscopy indicated that uranium accumulated intracellularly as needle-like fibrils. Uranium could be removed chemically from the cells, which could then be reused a a biosorbent. (orig.)

  1. Amino Alcohols from the Ascidian Pseudodistoma sp.

    Directory of Open Access Journals (Sweden)

    Tae Hyung Won

    2014-06-01

    Full Text Available Seven new amino alcohol compounds, pseudoaminols A–G (1–7, were isolated from the ascidian Pseudodistoma sp. collected off the coast of Chuja-do, Korea. Structures of these new compounds were determined by analysis of the spectroscopic data and from chemical conversion. The presence of an N-carboxymethyl group in two of the new compounds (6 and 7 is unprecedented among amino alcohols. Several of these compounds exhibited moderate antimicrobial activity and cytotoxicity, as well as weak inhibitory activity toward Na+/K+-ATPase.

  2. SP-100 design, safety, and testing

    Energy Technology Data Exchange (ETDEWEB)

    Smith, G.L.; Cox, C.M.; Mahaffey, M.K.

    1990-07-01

    The SP-100 Program is developing a nuclear reactor power system that can enhance and/or enable future civilian and military space missions. The program is directed to develop space reactor technology to provide electrical power in the range of tens to hundreds of kilowatts. The major nuclear assembly test is to be conducted at the Hanford Site near Richland, Washington, and is designed to validate the performance of the 2.4-MWt nuclear and heat transport assembly. 10 refs., 5 figs.

  3. Methyl (Sp-2-(diphenylphosphinoferrocene-1-carboxylate

    Directory of Open Access Journals (Sweden)

    Petr Štěpnička

    2009-10-01

    Full Text Available The title compound, [Fe(C5H5(C19H16O2P], obtained serendipitously during recrystallization of 1-hydroxybenzotriazolyl (Sp-2-(diphenylphosphinoferrocene-1-carboxylate from methanol, crystallizes in the chiral space group P212121. Its crystal structure not only confirms the anticipated absolute configuration but also establishes a rather regular geometry for the ferrocene unit, devoid of any significant deformation due to the attached substituents. In the crystal, symmetry-related molecules are linked via weak C—H...O interactions.

  4. Smart machines and the SP theory of intelligence

    OpenAIRE

    Wolff, J Gerard

    2014-01-01

    These notes describe how the "SP theory of intelligence", and its embodiment in the "SP machine", may help to realise cognitive computing, as described in the book "Smart Machines". In the SP system, information compression and a concept of "multiple alignment" are centre stage. The system is designed to integrate such things as unsupervised learning, pattern recognition, probabilistic reasoning, and more. It may help to overcome the problem of variety in big data, it may serve in pattern rec...

  5. Uji Pengaruh Beberapa Herbisida Terhadap Trichoderma sp Secara In Vitro

    OpenAIRE

    Majid, Muhammad

    2016-01-01

    Muhammad Majid: In Vitro Test on the Effect of Trichoderma sp Through Application of some Herbicides. Under Supervision ofHasanuddin and Mukhtar Iskandar Pinem. Herbicide is most commonly used pesticide, yet contained multiple negative effect on environment, especially towards soil microorganisms. This research’s objective is to study effect of herbicide with different concentration towards Trichoderma sp. Trichoderma sp has been inoculated in PDA which have been induced with six different...

  6. UJI POTENSI Gliocladium sp TERHADAP PERTUMBUHAN DAN PRODUKSI TANAMAN TOMAT

    OpenAIRE

    Lina Herlina

    2013-01-01

    AbstrakMikroorganisme tanah seperti Gliocladium sp dapat bertindak sebagai dekomposer dan juga sebagai agen pengendali hayati patogen tanaman hal ini memberikan harapan untuk mengurangi penggunaan pupuk dan fungisida sintetik. Tujuan penelitian untuk menguji potensi biofertililzer Gliocladium sp terhadap pertumbuhan dan produksi buah tomat. Variabel bebas yaitu bioferlizer Gliocladium sp  dengan dosis (g/tanaman) 0,50, 100, 150, dan 200 .Variabel tergantung adalah pertumbuhan dan produksi tan...

  7. Viability And Conidial Production Of Entomopathogenic Fungi Penicillium SP.

    OpenAIRE

    Nurariaty Agus; Annie P. Saranga; Ade Rosmana; Ade Sugiarti

    2015-01-01

    Abstract Penicillium sp. order Eurotiales class Eurotiomycetes family Trichocomaceae is one of the entomopathogenic fungi that have the potential to be developed as biological control agent of pests.The study aims to determine the viability and spora production of Entomopathogenic fungi Penicillium sp. Experiments was conducted in Pests Identification and Biological Control laboratory Department of Plant Pest and Disease Faculty of Agriculture Hasanuddin University. The fungus Penicillium sp....

  8. The effects of acupressure points in SP6 and SP8 on primary dysmenorrhea

    Directory of Open Access Journals (Sweden)

    Alireza Akbarzade

    2011-09-01

    Full Text Available Background: Dysmenorrhea is one of the most common disorders of women in reproductive age. In addition to physical and psychological disturbances, it may cause socioeconomic problems. The acupressure is a suggested treatments for dysmenorrhea. This study was conducted to identify and compare the effects of acupressure in Saninjo and DiJi points on pain severity of primary dysmenorrhea and systematic symptoms associated with it. Methods: This study was a cross-over clinical trial. 50 girls aged between 18 and 30 years old referred to an urban health center in Sar-e-Pol-e-Zahab city were selected. Subjects randomly allocated into two equal groups (A and B and were assessed over three consecutive menstrual cycles. A questionnaire was used for data collection. Validity and reliability determined by content validity and test retest methods respectively. Pain severity was assessed using McGill pain ruler. At the end, data from 42 women were used for analysis with SPSS package.Results: The severity of primary dysmenorrhea was 6.65±1.05 in SP6 and 6.84 ±1.9 in SP8 before acupressure and significantly decreased to 2.89±1.36 and 2.03±0.94 respectively after acupressure (P<0.001. Conclusion: We can conclude that dysmenorrhea pain decreased after acupressure and SP6 and SP8 points can be used as an urgent remedy to alleviate primary dysmenorrhea.

  9. Mineralization of a Malaysian crude oil by Pseudomonas sp. and Achromabacter sp. isolated from coastal waters

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, J.; Ahmad, M.F.

    1995-12-31

    Regarded as being a potentially effective tool to combat oil pollution, bioremediation involves mineralization, i.e., the conversion of complex hydrocarbons into harmless CO{sub 2} and water by action of microorganisms. Therefore, in achieving optimum effectiveness from the application of these products on crude oil in local environments, the capability of the bacteria to mineralize hydrocarbons was evaluated. The microbial laboratory testing of mineralization on local oil degraders involved, first, isolation of bacteria found at a port located on the west coast of Peninsular Malaysia. Subsequently, these bacteria were identified by means of Biomereux`s API 20E and 20 NE systems and later screened by their growth on a Malaysian crude oil. Selected strains of Pseudomonas sp. and Achromabacter sp. were then exposed individually to a similar crude oil in a mineralization unit and monitored for 16 days for release of CO{sub 2}. Pseudomonas paucimobilis was found to produce more CO{sub 2} than Achromobacter sp. When tested under similar conditions, mixed populations of these two taxa produced more CO{sub 2} than that produced by any individual strain. Effective bioremediation of local crude in Malaysian waters can therefore be achieved from biochemically developed Pseudomonas sp. strains.

  10. Biodegradation of hexavalent chromium (Cr+6) in wastewater using Pseudomonas sp. and Bacillus sp. bacterial strains

    Energy Technology Data Exchange (ETDEWEB)

    Qasim, Muhammad [Department of Chemical Engineering, American University of Sharjah (United Arab Emirates)

    2013-07-01

    The recovery of toxic metal compounds is a deep concern in all industries. Hexavalent chromium is particularly worrying because of its toxic influence on human health. In this paper, biodegradation of hexavalent chromium (Cr+6) present in wastewater has been studied using two different bacterial strains; Pseudomonas sp. and Bacillus sp. A chemostat (with and without recycle of cells) with 10 L liquid culture volume was used to study the substrate and the biomass cell concentrations with time. Also, the degree of substrate conversion was studied by the varying the dilution rate as an independent parameter. The dilution rate (ratio of feed flow rate to the culture volume) was varied by varying the feed volumetric rate from 110-170 mL/h for inlet hexavalent chromium concentrations of 70 mg/dm3. The results show that a chemostat with recycle gives a better performance in terms of substrate conversion than a chemostat without a recycle. Moreover, the degree of substrate conversion decreases as the dilution rate is increased. Also, Bacillus sp. was found to give higher conversions compared to pseudomonas sp.

  11. Maize responds to Azotobacter sp and Burkholderia sp inoculation at reduced dose of nitrogen fertilizer

    Directory of Open Access Journals (Sweden)

    Juan Manuel Sánchez-Yáñez

    2014-03-01

    Full Text Available The positive maize response to inoculation with plant growth promoting bacteria (PGPB as Azotobacter sp and Burkholderia sp an endophytic type, are an alternative to reduced and optimize nitrogen fertilizer (NF dose, recommended for this plant, without adversely affect its growth. The aim of this study was to analyze maize respond to inoculation with Azotobacter sp and Burkholderia sp at the dose 50% of FN. Used an experimental design of randomized blocks. By response variables: percent germination (%, the shoot and root phenology: plant height (PH, root length (RL and biomass: shoot fresh weight (SFW and root fresh weight (RFW, the shoot dry weight (SDW and root dry weight (RDW. The results indicated a positive maize respond to PGPB inoculation at germination, seedling and flowering level, reached a RDW of 7.03 g, statistically significant value compared with 2.60 g of RDW non inoculated maize feed with NF dose recommended regard as relative control (RC. This suggests a synergistic interaction among these PGPB in synthesis of plant growth promoting substances (PGPS on maize, to optimize the reduced NF dose.

  12. Auxiliary tensor fields for Sp(2,R) self-duality

    CERN Document Server

    Ivanov, Evgeny A; Zupnik, Boris M

    2014-01-01

    The coset Sp(2,R)/U(1) is parametrized by two real scalar fields. We generalize the formalism of auxiliary tensor (bispinor) fields in U(1) self-dual nonlinear models of abelian gauge fields to the case of Sp(2,R) self-duality. In this new formulation, Sp(2,R) duality of the nonlinear scalar-gauge equations of motion is equivalent to an Sp(2,R) invariance of the auxiliary interaction. We derive this result in two different ways, aiming at its further application to supersymmetric theories. We also consider an extension to interactions with higher derivatives.

  13. Microbial transformation of citral by Penicillium sp..

    Science.gov (United States)

    Esmaeili, Akbar; Tavassoli, Afsaneh

    2010-01-01

    Thymol is present in the essential oils from herbs and spices, such as thyme. It is produced by these plant species as a chemical defense against phytopathogenic microorganisms. Therefore, this compound has attracted great attention in food industry, i.e., it has been used as a natural preservative in foods such as cheese to prevent fungal growth. Previous studies concerning the biotransformation of nerol by Penicillium sp. and microbial transformation of citral by sporulated surface cultures method (SSCM) of Penicillium digitatum have been reported. The objective of this research was to study the pathway involved during biotransformation of citral by Penicillium sp. using two methods. The culture preparation was done using different microbial methods and incubation periods to obtain Penicillium for citral biotransformation. The biotransformation products were identified by gas chromatography (GC) and gas chromatography/mass spectroscopy (GC/MS). A comparison of the two methods showed that SSCM was more effective, its major products were thymol (21.5 %), geranial (18.6 %) and nerol (13.7 %). LM produced only one compound — thymol — with a low efficiency. PMID:20842292

  14. The Effect of Acupuncture to SP6 on Skin Temperature Changes of SP6 and SP10: An Observation of “Deqi”

    Directory of Open Access Journals (Sweden)

    Jia-Min Yang

    2014-01-01

    Full Text Available Background. Deqi sensation is a complex but an important component for acupuncture effect. In this study, we tried to observe the relationship between Deqi and skin temperature changes and whether there was some relativity between Deqi and needle stimulations on cold congealing and dysmenorrhea rat model. Thirty-two female Sprague Dawley (SD rats were randomly divided into four groups (Saline Control Group, Model Group, Group A with strong stimulation, and Group B with small stimulation. Group A and Group B were performed with different stimulations. We found that, compared with saline control group, model group, and Group B, Group A showed that the skin temperature changes on right acupoint SP6 and SP10 increased significantly at 5 min–10 min interval. The skin temperature changes on left SP6 decreased at instant–5 min interval. The skin temperature changes on right SP10 decreased significantly at instant–5 min interval and 10 min–20 min interval. Thermogenic action along Spleen Meridian of Foot Greater Yin was manifested as simultaneous skin temperature increase on right SP6 and SP10 at 5 min–10 min interval after needling SP6, which was helpful to illustrate the relationship between the characteristic of Deqi and needle stimulations.

  15. Highly Prevalent Coxiella sp. Bacterium in the Tick Vector Amblyomma americanum▿

    OpenAIRE

    Jasinskas, Algimantas; Zhong, Jianmin; Barbour, Alan G.

    2006-01-01

    Laboratory-reared and field-collected Amblyomma americanum ticks were hosts of a Coxiella sp. and a Rickettsia sp. While the Coxiella sp. was detected in 50 of 50 field-collected ticks, the Rickettsia sp. was absent from 32% of ticks. The Coxiella sp. showed evidence of a reduced genome and may be an obligate endosymbiont.

  16. Integrative Gene Cloning and Expression System for Streptomyces sp. US 24 and Streptomyces sp. TN 58 Bioactive Molecule Producing Strains

    Directory of Open Access Journals (Sweden)

    Samiha Sioud

    2009-01-01

    Full Text Available Streptomyces sp. US 24 and Streptomyces sp. TN 58, two strains producing interesting bioactive molecules, were successfully transformed using E. coli ET12567 (pUZ8002, as a conjugal donor, carrying the integrative plasmid pSET152. For the Streptomyces sp. US 24 strain, two copies of this plasmid were tandemly integrated in the chromosome, whereas for Streptomyces sp. TN 58, the integration was in single copy at the attB site. Plasmid pSET152 was inherited every time for all analysed Streptomyces sp. US 24 and Streptomyces sp. TN 58 exconjugants under nonselective conditions. The growth, morphological differentiation, and active molecules production of all studied pSET152 integrated exconjugants were identical to those of wild type strains. Consequently, conjugal transfer using pSET152 integration system is a suitable means of genes transfer and expression for both studied strains. To validate the above gene transfer system, the glucose isomerase gene (xylA from Streptomyces sp. SK was expressed in strain Streptomyces sp. TN 58. Obtained results indicated that heterologous glucose isomerase could be expressed and folded effectively. Glucose isomerase activity of the constructed TN 58 recombinant strain is of about eighteenfold higher than that of the Streptomyces sp. SK strain. Such results are certainly of importance due to the potential use of improved strains in biotechnological process for the production of high-fructose syrup from starch.

  17. Lung surfactant protein A (SP-A) interactions with model lung surfactant lipids and an SP-B fragment.

    Science.gov (United States)

    Sarker, Muzaddid; Jackman, Donna; Booth, Valerie

    2011-06-01

    Surfactant protein A (SP-A) is the most abundant protein component of lung surfactant, a complex mixture of proteins and lipids. SP-A performs host defense activities and modulates the biophysical properties of surfactant in concerted action with surfactant protein B (SP-B). Current models of lung surfactant mechanism generally assume SP-A functions in its octadecameric form. However, one of the findings of this study is that when SP-A is bound to detergent and lipid micelles that mimic lung surfactant phospholipids, it exists predominantly as smaller oligomers, in sharp contrast to the much larger forms observed when alone in water. These investigations were carried out in sodium dodecyl sulfate (SDS), dodecylphosphocholine (DPC), lysomyristoylphosphatidylcholine (LMPC), lysomyristoylphosphatidylglycerol (LMPG), and mixed LMPC + LMPG micelles, using solution and diffusion nuclear magnetic resonance (NMR) spectroscopy. We have also probed SP-A's interaction with Mini-B, a biologically active synthetic fragment of SP-B, in the presence of micelles. Despite variations in Mini-B's own interactions with micelles of different compositions, SP-A is found to interact with Mini-B in all micelle systems and perhaps to undergo a further structural rearrangement upon interacting with Mini-B. The degree of SP-A-Mini-B interaction appears to be dependent on the type of lipid headgroup and is likely mediated through the micelles, rather than direct binding.

  18. Potential topical natural repellent against Ae. aegypti, Culex sp. and Anopheles sp. mosquitoes

    Directory of Open Access Journals (Sweden)

    Dewi Nur Hodijah

    2014-08-01

    Full Text Available AbstrakLatar belakang:Minyak atsiri daun sirih diketahui mempunyai daya proteksi. Dibuatkan losion berdasarkan pengantar sediaan farmasi yang ditambahkan minyak atsiri daun nilam. Sediaan losion dipilih agar dapat menempel lebih lama di permukaan kulit. Tujuan penelitian ini untuk membandingkan daya proteksi antara losion dengan penambahan minyak nilam dan losion tanpa penambahan minyak nilam dibandingkan daya proteksi dengan DEET. Metode: Penelitian ini merupakan penelitian eksperimental laboratorium. Semua nyamuk uji berasal dari insektarium laboratorium penelitian kesehatan Loka litbang P2B2 Ciamis. Konsentrasi minyak atsiri daun sirih dalam losion adalah 4%; konsentrasi minyak nilam sebagai zat pengikat adalah 0,4%. Formula yang digunakan yaitu formula dasar yang ada pada pengantar sediaan farmasi. Uji repelensi dilakukan dengan menggunakan metoda yang direkomendasikan oleh Komisi pestisida.Hasil: Dihasilkan formulasi losion yang stabil dan masih memenuhi standar formulasi sediaan. Berdasarkan hasil, diperoleh data bahwa DEET dan losion hasil modifikasi memiliki rata-rata daya proteksi di atas 90% selama 6 jam terhadap nyamuk Ae.aegypti dan Culex sp. Kesimpulan: Penambahan minyak nilam pada losion sirih dapat meningkatkan daya proteksi terhadap hinggapan nyamuk Ae. aegypti dan Culex sp. (Health Science Indones 2014;1:44-8Kata kunci:repelen alamiah, minyak atsiri, daun sirih, daun nilam, Ae. aegypti, Culex sp.AbstractBackground: Betel leaf essential oil lotion has been known to have insect repellent properties. A lotion was made based on a pharmaceutical formula from a monograph where patchouli leaf essential oil was added. A lotion preparation was intended to enhance adherence of the formula on the surface of the skin. The purpose of this study was to compare protection percentage of lotion with patchouli oil and without patchouli oil lotion compared to DEET.Methods: This study is an experimental laboratory-based research. All mosquitoes

  19. Pneumonitis and emphysema in sp-C gene targeted mice.

    Science.gov (United States)

    Glasser, Stephan W; Detmer, Emily A; Ikegami, Machiko; Na, Cheng-Lun; Stahlman, Mildred T; Whitsett, Jeffrey A

    2003-04-18

    SP-C-deficient (SP-C -/-) mice developed a severe pulmonary disorder associated with emphysema, monocytic infiltrates, epithelial cell dysplasia, and atypical accumulations of intracellular lipids in type II epithelial cells and alveolar macrophages. Whereas alveolar and tissue surfactant phospholipid pools were increased, levels of other surfactant proteins were not altered (SP-B) or were modestly increased (SP-A and SP-D). Analysis of pressure-volume curves and forced oscillatory dynamics demonstrated abnormal respiratory mechanics typical of emphysema. Lung disease was progressive, causing weight loss and cardiomegaly. Extensive alveolar remodeling was accompanied by type II cell hyperplasia, obliteration of pulmonary capillaries, and widespread expression of alpha-smooth muscle actin, indicating myofibroblast transformation in the lung parenchyma. Dysplastic epithelial cells lining conducting airways stained intensely for the mucin, MUC5A/C. Tissue concentrations of proinflammatory cytokines were not substantially altered in the SP-C (-/-) mice. Production of matrix metalloproteinases (MMP-2 and MMP-9) was increased in alveolar macrophages from SP-C (-/-) mice. Absence of SP-C caused a severe progressive pulmonary disorder with histologic features consistent with interstitial pneumonitis. PMID:12519727

  20. Post-neonatal drop in alveolar SP-A expression

    DEFF Research Database (Denmark)

    Stray-Pedersen, Arne; Vege, Ashild; Stray-Pedersen, Asbjorg;

    2008-01-01

    was developed enabling semi-quantitative estimation of staining intensity and distribution. RESULTS: SP-A was detected in the terminal bronchioles and alveolar spaces of fetuses >35 weeks gestation. The intra-alveolar SP-A expression increased in the perinatal period followed by a marked drop in infants aged...

  1. Monochroa bronzella sp. n. from the southwestern Alps (Lepidoptera: Gelechiidae)

    DEFF Research Database (Denmark)

    Karsholt, Ole; Nel, Jacques; Fournier, François;

    2013-01-01

    Abstract. Monochroa bronzella sp. n. is described from the southwestern Alps (France, Italy). It is closely related to M. nomadella (Zeller, 1868), with which it was hitherto confused. Literature records of M. nomadella from France and northwestern Italy refer to M. bronzella sp. n. The two speci...

  2. Brachystelma nallamalayana sp. Nov. (Apocynaceae: Asclepiadoideae: Ceropegieae from India

    Directory of Open Access Journals (Sweden)

    K. Prasad

    2014-10-01

    Full Text Available Brachystelma nallamalayana sp. nov., collected from Nallamalais, the Eastern Ghats of Andhra Pradesh, India is described and illustrated. The new species is compared to its closest species, Brachystelma maculatum Hook. f. Brachystelma nallamalayana, sp. nov. is distinct from other species of Brachystelma in having ca 80cm high glabrous stems, peduncled cymes, basally united calyx lobes and biseriate corona.

  3. SP Monitoring of Intermittent Flow Through Covered-Karst Sinkholes

    Science.gov (United States)

    Bumpus, P. B.; Kruse, S. E.

    2010-12-01

    A year of continuous SP (self-potential) monitoring was combined with high-resolution 3-D GPR surveys and intermittent water table monitoring over two small covered-karst conduits in Tampa, Florida. SP readings were logged over ~30 electrodes at 2-minute intervals. Positive and negative SP anomalies episodically manifested over conduits, suggesting that conduit flow is dynamic, not static. Three distinct SP flow regimes in the conduits are postulated: fast flow through the conduit to the underlying aquifer, slow flow to the confining layer through the collapse conduit walls, and a conduit plugged high enough to behave like the rest of the confining layer. SP responses after rain events appear to measure the effects of two wetting front curves, one striking the monitoring electrode, one the reference. By comparing curve shapes for all possible pairs of electrodes, it may be possible to establish surficial infiltration and flow patterns. SP is also strongly affected by soil conductivity, rainfall history, and cultural noise. Further concurrent study of moisture content and SP with a suite of reference electrodes placed in various topographic, vegetative, geologic, and climatic settings will help distinguish groundwater flow from other sources affecting SP measurements.

  4. Truncated recombinant human SP-D attenuates emphysema and type II cell changes in SP-D deficient mice

    Directory of Open Access Journals (Sweden)

    Mühlfeld Christian

    2007-10-01

    Full Text Available Abstract Background Surfactant protein D (SP-D deficient mice develop emphysema-like pathology associated with focal accumulations of foamy alveolar macrophages, an excess of surfactant phospholipids in the alveolar space and both hypertrophy and hyperplasia of alveolar type II cells. These findings are associated with a chronic inflammatory state. Treatment of SP-D deficient mice with a truncated recombinant fragment of human SP-D (rfhSP-D has been shown to decrease the lipidosis and alveolar macrophage accumulation as well as production of proinflammatory chemokines. The aim of this study was to investigate if rfhSP-D treatment reduces the structural abnormalities in parenchymal architecture and type II cells characteristic of SP-D deficiency. Methods SP-D knock-out mice, aged 3 weeks, 6 weeks and 9 weeks were treated with rfhSP-D for 9, 6 and 3 weeks, respectively. All mice were sacrificed at age 12 weeks and compared to both PBS treated SP-D deficient and wild-type groups. Lung structure was quantified by design-based stereology at the light and electron microscopic level. Emphasis was put on quantification of emphysema, type II cell changes and intracellular surfactant. Data were analysed with two sided non-parametric Mann-Whitney U-test. Main Results After 3 weeks of treatment, alveolar number was higher and mean alveolar size was smaller compared to saline-treated SP-D knock-out controls. There was no significant difference concerning these indices of pulmonary emphysema within rfhSP-D treated groups. Type II cell number and size were smaller as a consequence of treatment. The total volume of lamellar bodies per type II cell and per lung was smaller after 6 weeks of treatment. Conclusion Treatment of SP-D deficient mice with rfhSP-D leads to a reduction in the degree of emphysema and a correction of type II cell hyperplasia and hypertrophy. This supports the concept that rfhSP-D might become a therapeutic option in diseases that are

  5. Meroterpenoids from a Tropical Dysidea sp. Sponge.

    Science.gov (United States)

    Kim, Chang-Kwon; Woo, Jung-Kyun; Kim, Seong-Hwan; Cho, Eunji; Lee, Yeon-Ju; Lee, Hyi-Seung; Sim, Chung J; Oh, Dong-Chan; Oh, Ki-Bong; Shin, Jongheon

    2015-11-25

    Six new meroterpenoids (1-6), along with arenarol (7), a known rearranged drimane sesquiterpene hydroquinone, were isolated from a Dysidea sp. sponge collected from the Federated States of Micronesia. On the basis of the results of combined spectroscopic analysis, compound 1 was determined to be the cyclic ether derivative of 7, whereas 2 and 3 were assigned as the corresponding sesquiterpene quinones containing taurine-derived substituents. Compounds 4-6 possess a novel tetracyclic skeleton formed by a direct linkage between the quinone and sesquiterpene moieties. The configurations of these new compounds were assigned on the basis of combined NOESY and ECD analysis. These compounds exhibited cytotoxic and antimicrobial activities and weak inhibition against Na(+)/K(+)-ATPase. PMID:26551342

  6. Digitization of Sp\\"orer's sunspot drawings

    CERN Document Server

    Diercke, Andrea; Denker, Carsten

    2012-01-01

    Much of our knowledge about the solar dynamo is based on sunspot observations. It is thus desirable to extend the set of positional and morphological data of sunspots into the past. Gustav Sp\\"orer observed in Germany from Anklam (1861-1873) and Potsdam (1874-1894). He left detailed prints of sunspot groups, which we digitized and processed to mitigate artifacts left in the print by the passage of time. After careful geometrical correction, the sunspot data are now available as synoptic charts for almost 450 solar rotation periods. Individual sunspot positions can thus be precisely determined and spot areas can be accurately measured using morphological image processing techniques. These methods also allow us to determine tilt angles of active regions (Joy's law) and to assess the complexity of an active region.

  7. Biodegradation of malachite green by Ochrobactrum sp.

    Science.gov (United States)

    Vijayalakshmidevi, S R; Muthukumar, Karuppan

    2014-02-01

    This study presents the biodegradation of malachite green (MG), a triphenylmethane dye, using a novel microorganism isolated from textile effluent contaminated environment. The organism responsible for degradation was identified as Ochrobactrum sp JN214485 by 16S rRNA analysis. The effect of operating parameters such as temperature, pH, immobilized bead loading, and initial dye concentration on % degradation was studied, and their optimal values were found to be 30 °C, 6, 20 g/L and 100 mg/L, respectively. The analysis showed that the extracellular enzymes were responsible for the degradation. The biodegradation of MG was confirmed by UV-visible spectroscopic and FTIR analysis. The phytotoxicity test concluded that the degradation products were less toxic compared to MG. The kinetics of biodegradation was studied and the activation energy was found to be 10.65 kcal/mol.

  8. Ovos de Toxocara sp. e larvas de Ancylostoma sp. em praça pública de Lavras, MG Toxocara sp. eggs and Ancylostoma sp. larva in public parks, Brazil

    OpenAIRE

    Antônio Marcos Guimarães; Endrigo Gabellini Leonel Alves; Glycia Ferreira de Rezende; Marcelo Costa Rodrigues

    2005-01-01

    Larva migrans visceral e cutânea são zoonoses parasitárias causadas pela infecção da larva de Toxocara sp. e Ancylostoma sp., respectivamente. O objetivo do estudo foi verificar a contaminação por ovos de Toxocara sp. e ovos e larvas de Ancylostoma sp. em amostras de solos coletadas de praças públicas e de áreas de recreação infantil de Lavras, Estado de Minas Gerais, por meio da técnica de centrífugo-flutuação e do método de Baermann. A ocorrência de ovos de Toxocara sp. e, ovos e larvas de ...

  9. Properties of Polyhydroxyalkanoate Granules and Bioemulsifiers from Pseudomonas sp. and Burkholderia sp. Isolates Growing on Glucose.

    Science.gov (United States)

    Sacco, Laís Postai; Castellane, Tereza Cristina Luque; Lopes, Erica Mendes; de Macedo Lemos, Eliana Gertrudes; Alves, Lúcia Maria Carareto

    2016-03-01

    A Burkholderia and Pseudomonas species designated as AB4 and AS1, respectively, were isolated from soil containing decomposing straw or sugar cane bagasse collected from Brazil. This study sought to evaluate the capacities of culture media, cell-free medium, and crude lysate preparations (containing PHB inclusion bodies) from bacterial cell cultures to stabilize emulsions with several hydrophobic compounds. Four conditions showed good production of bioemulsifiers (E24 ≥ 50 %), headed by substantially cell-free media from bacterial cell cultures in which bacterial isolates from Burkholderia sp. strain AB4 and Pseudomonas sp. strain AS1 were grown. Our results revealed that the both isolates (AB4 and AS1 strains) exhibited high emulsification indices (indicating usefulness in bioremediation) and good stabilities. PMID:26578147

  10. Actinoplanes lichenis sp. nov., isolated from lichen.

    Science.gov (United States)

    Phongsopitanun, Wongsakorn; Matsumoto, Atsuko; Inahashi, Yuki; Kudo, Takuji; Mori, Mihoko; Shiomi, Kazuro; Takahashi, Yoko; Tanasupawat, Somboon

    2016-01-01

    A novel species of the genus Actinoplanes, strain LDG1-22T, for which we propose the name Actinoplanes lichenis sp. nov., was isolated from a lichen sample collected from tree bark in Thailand. The taxonomic position of the species has been described based on a polyphasic approach. Strain LDG1-22T produced irregular sporangia on agar media. It contained meso-diaminopimelic acid in the cell-wall peptidoglycan. The major menaquinone was MK-9(H4); the polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides and phosphatidylglycerol. Whole-cell hydrolysates contained ribose, glucose, mannose and small amounts of arabinose and xylose. The major cellular fatty acids were anteiso-C15 : 0 (31.2 %) and iso-C16 : 0 (14.2 %). Mycolic acids were absent. The G+C content was 73.6 %. 16S rRNA gene sequence analysis of strain LDG1-22T showed highest similarity (98.8 %) to Actinoplanes friuliensis DSM 45797T and it clustered with Actinoplanes nipponensis JCM 3264T and Actinoplanes missouriensis JCM 3121T in phylogenetic tree analysis. On the basis of the phenotypic characteristics and DNA-DNA relatedness, strain LDG1-22T could be distinguished from related species of the genus Actinoplanes and so represents a novel species of this genus. The type strain of Actinoplanes lichenis sp. nov. is LDG1-22T ( = JCM 30485T = TISTR 2343T = PCU 344T). PMID:26552374

  11. Murine fertilized ovum, blastomere and morula cells lacking SP phenotype

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In the field of stem cell research, SP (side population) phenotype is used to define the property that cells maintain a high efflux capability for some fluorescent dye, such as Hoechst 33342. Recently, many researches proposed that SP phenotype is a phenotype shared by some stem cells and some progenitor cells, and that SP phenotype is regarded as a candidate purification marker for stem cells. In this research, murine fertilized ova (including conjugate and single nucleus fertilized ova), 2-cell stage and 8-cell stage blastomeres, morulas and blastocysts were isolated and directly stained by Hoechst 33342 dye. The results show that fertilized ovum, blastomere and morula cells do not demonstrate any ability to efflux the dye. However, the inner cell mass (ICM) cells of blastocyst exhibit SP phenotype, which is consistent with the result of embryonic stem cells (ESCs) in vitro. These results indicate that the SP phenotype of ICM-derived ESCs is an intrinsic property and independent of the culture condition in vitro, and that SP phenotype is one of the characteristics of at least some pluripotent stem cells, but is not shared by totipotent stem cells. In addition, the result that the SP phenotype of ICM cells disappeared when the inhibitor verapamil was added into medium implies that the SP phenotype is directly associated with ABCG2. These results suggest that not all the stem cells demonstrate SP phenotype, and that SP phenotype might act as a purification marker for partial stem cells such as some pluripotent embryonic stem cells and multipotent adult stem cells, but not for all stem cells exampled by the totipotent stem cells in the very early stage of mouse embryos.

  12. Carotenoid Contents in Anoxygenic Phototrophic Purple Bacteria, Marichromatium Sp. and Rhodopseudomonas Sp. of Tropical Environment, Malaysia

    Directory of Open Access Journals (Sweden)

    Zaima Azira

    2014-06-01

    Full Text Available Carotenoids have shown extensive applications in pharmaceutical, aquaculture and animal feed industries. Recently, researchers have been studied on their potentiality for the health benefits in reducing the risk of cancer and neurodegenerative diseases. Based on above perspectives a study was conducted in tropical environment to evaluate the total carotenoid content, dry cell weight and bacteriochlorophyll type of phototrophic purple bacteria;Marichromatium sp. and Rhodopseudomonas sp. The bacteria Marichromatium sp. was isolated from the mangrove sediments, Kuantan Pahang. While, Rhodopseudomonas sp. was collected from fish rearing tanks INOCEM, IIUM. The bacteria were cultivated and monitored by using 112 media under anaerobic light conditions at 2500-lux light intensity of continuous illumination of 60-watt tungsten bulb at 30±2°C. Total carotenoid contents and dry cell weight of the bacterial cells were compared from day 0 to day 5 using UV-VIS spectrometer. Bacteriochlorophyll type was also determined using UV-VIS spectrometer. The results showed that isolate IIUM-JHR2 produced the highest total carotenoid content (4.08±2.21mg/g at day 3 while IIUM-JHM1produced the highest dry cell weight (3.83±1.57 g/L at day 2. Statistical analysis showed significance differences (p0.05 detected for total carotenoid contents among the species. However, live cell cultures exhibited absorption maxima at 382, 495.5, 524, 591, 806 and 864 nm in all isolates indicating the presence of bacteriochlorophylla and carotenoids belonging to the spirilloxanthin series. The finding reveals that these bacteria could be utilized in aquaculture as fish feed supplement to enhance growth, survival and coloration of cultured fishes. Furthermore, they can play significant role as potential elements towards food and pharmaceutical industries.

  13. Enzyme-linked imunoassays for the detection of Listeria sp. and Salmonella sp. in sausage: a comparison with conventional methods.

    Science.gov (United States)

    Benetti, T M; Monteiro, C L B; Beux, M R; Abrahão, W M

    2013-01-01

    This study was carried out comparing the conventional methods (ISO 11290-1 and BAM method, 2008) and system mini-Vidas® (Biomerieux), for detection of Listeria sp. and Salmonella sp. in cooled sausage. The immunoenzymatic method has shown to be effective for the detection of target pathogens, it has presented itself as an excellent screening method.

  14. Plant growth promoting potential of pseudomonas sp. SP0113 isolated from potable water from a closed water well

    OpenAIRE

    Przemieniecki Wojciech Sebastian; Kurowski Paweł Tomasz; Karwowska Anna

    2015-01-01

    The Pseudomonas sp. SP0113 strain from a partially closed aquatic environment was identified as a plant growth promoting bacterium (PGPB). Laboratory tests revealed that PS0113 has multiple plant growth promoting traits, including mineral phosphate solubilizing ability, ammonifying ability that increases nitrogen availability for plants via the root system, and phosphatase activity that plays an important role in organic phosphorus mineralization. Tricalciu...

  15. Life cycle and secondary production of two mayflies Leptophlebia sp. And Ephemera sp. In Heizhuchong stream, Hubei, China

    Institute of Scientific and Technical Information of China (English)

    LI Xiaoyu; YAN Yunjun

    2008-01-01

    From June 2003 to June 2004,an investigation on the life cycle,production and trophic basis of dominant species of macrozoobenthos community in a second-order river of the Hanjiang River basin,Hubei,China was carried out.The results showed that the dominant species Leptophlebia sp.and Ephemera sp.appeared to develop two generations per year,and there was a small overlap in the two generations of both species.The pupation of Leptophlebia sp.mainly occurred in autumn and winter,while pupation of Ephemera sp.mainly took place in summer and winter.The standing stocks of the Leptophlebia sp.population and Ephemera sp.population had two peaks in a year.The cohort production and cohort P/B ratio of the Leptophlebia sp.population estimated by size frequency method were 19.018 1 g/m2.a and 5.7 respectively,while its annual production and P/B ratio were 38.036 2 g/m2.a and 11.4.The cohort production and cohort P/B ratio of the Ephemera sp.population were 38.015 9 g/m2.a and 5.9,while its annual production and P/B ratio were 76.0318 g/m2.a and 11.8.

  16. Desulfuromonas svalbardensis sp nov and Desulfuromusa ferrireducens sp nov., psychrophilic, Fe(III)-reducing bacteria isolated from Arctic sediments, Svalbard

    DEFF Research Database (Denmark)

    Vandieken, V.; Mussmann, M.; Niemann, Hans Henrik;

    2006-01-01

    succinoxidans Gylac(T) (95.9%) within the Deltaproteobacteria. Strains 112(T) and 102(T) therefore represent novel species, for which the names Desulfuromonas svalbardensis sp. nov. (type strain 112(T) = DSM 16958(T) = JCM 12927(T)) and Desulfuromusa ferrireducens sp. nov. (type strain 102(T) = DSM 16956 (T...

  17. Fusarium euwallaceae sp. nov.—a symbiotic fungus of Euwallacea sp., an invasive ambrosia beetle in Israel and California

    Science.gov (United States)

    The invasive Asian ambrosia beetle Euwallacea sp. (Coleoptera, Scolytinae, Xyleborini) and a novel Fusarium sp. that it farms in its galleries as a source of nutrition seriously damage over 20 species of live trees and pose a serious threat to avocado production (Persea americana) in Israel and Cali...

  18. PENGGUNAAN EKSTRAK BIOTA LAUTAGLAOPHENIA SP. UNTUK MENGENDALIKANFUSARIUM OXYSPORUM F.SP.VANILLAE PENYEBAB BUSUK BATANG VANILI

    Directory of Open Access Journals (Sweden)

    I KETUT SUADA

    2012-11-01

    Full Text Available The Use of Aglaophenia sp. Marine Biota Extract to Control Fusarium oxysporum f. sp. vanillae, a Pathogen of Vanilla Stem Rot The use of marine biota for organic fungicide material has enormous potential to be developed. The organic fungicide was directed to substitute synthetic fungicide for vanilla cultivation. Application of synthetic fungicide degraded environmental quality, therefore its applications does not support sustainable agriculture. The objective of this research was to know the potence of Aglaopheniain suppressing the growth of F. oxysporum f. sp.vanillae, the pathogen of vanilla stem rot. The research was done in green house in order to find the best substance for formulation of the extract. The substances screened were water, tween-80, and detergents with two different concentrations. Subsequently, two best formulas were chosen to apply in endemic area in Tabanan. The green house and field trial research used Randomized Completely Design with three and five replications respectively. Results showed that tween was the best substance used for formulation and concentration of 0.2% was better than other concentrations. The extract diluted in tween-80 on the concentration of 0.2% showed the lowest rot on stem, longest shoot, and the most leaves on vanilla shoot. Because of its significant performance, the 0.1% extract ofAglaopheniain 0.1% tween-80 was proposed to be the best formula to suppress the vanilla stem rot disease.

  19. Ethmolaimus riparius sp. n. and Paramononchus major sp. n. (Nematoda) from Lake Baikal, Russia.

    Science.gov (United States)

    Gagarin, Vladimir G; Naumova, Tatyana V

    2016-01-01

    Two new nematode species found in Lake Baikal (Russia) are described and illustrated. Ethmolaimus riparius sp. n. is morphologically close to E. pilosus Shoshin, 1998 and E. lanatus Shoshin, 1998. The new species differs from E. pilosus by the longer and thinner body (L = 1228-1501 µm, a = 26-34 vs L = 720-1070 µm, a = 19-23), larger stoma (26-32 µm long vs 19-24 µm long), longer spicules and gubernaculum (45-50 µm long and 21-25 µm long vs accordingly 32-37 µm long and 8 µm long). E. riparius sp. n. differs from E. lanatus by the longer body (L = 1228-1501 µm vs L = 680-1180), shorter cephalic setae (its length is equal 1.1-1.4 labial region diameter vs 1.6-2.1 labial region diameter) and longer spicules and gubernaculum (45-50 µm long and 21-25 µm long vs accordingly 25-30 µm long and 7-8 µm long). Paramononchus major sp. n is close to P. orientalis Gagarin & Naumova, 2012, but differs from it by the longer body (L = 5926-7820 µm vs L = 3081-3778 µm), longer spicules (410-475 µm long vs 208-238 µm long) and larger number of precloacal supplements (52-61 vs 21-24). Keys for the identification of valid species of the genera Ethmolaimus and Paramononchus are given. PMID:27394603

  20. Efektivitas Ovitrap Bambu terhadap Jumlah Jentik Aedes sp yang Terperangkap

    Directory of Open Access Journals (Sweden)

    Wiwit Aditama

    2015-05-01

    places of 10 subdistricts. Data of trapped Aedes sp larvae numbers was collected four times repeatedly within one week time-lapse. Analysis was conducted using the mean number of larvae in ovitraps and ovitrap index. The number of Aedes sp larvae trapped was 1,265. The most effective ovitrap is piece of bamboo, mean = 123, p value = 0.006, HI = 10.01% (16.66 26.67%, CI = 36.8% (336.06 - 39.74%, BI = 29.97% (73.33 - 103.3%. Health authorities should promote bamboo ovitrap, especially to public as an effort to control Aedes sp.

  1. Aspectos reproductivos del cladocero Moinodaphnia sp. en condiciones de laboratorio.

    OpenAIRE

    Prieto G., Martha

    2001-01-01

    Realizar un cultivo experimental de cladócero Moina sp alimentado con Ankistrodesmus sp y Saccharomyces cereviseae. Fueron realizados cultivos experimentales de la cepa de cladóceros Moina sp en el laboratorio de Alimento Vivo de la Universidad de Córdoba, bajo condiciones controladas de temperatura (22°C), pH (7.6), intensidad lumínica (2000 lux) y aireación. Se emplearon dos dietas de alimento como tratamiento (Ankistrodesmus y Ankistrodesmus mas Saccharomyces cereviseae) en concentrac...

  2. Linking surfactant protein SP-D and IL-13

    DEFF Research Database (Denmark)

    Qaseem, Asif S; Sonar, Sanchaita; Mahajan, Lakshna;

    2012-01-01

    Surfactant protein D (SP-D) is an innate immune molecule that plays a protective role against lung infection, allergy, asthma and inflammation. In vivo experiments with murine models have shown that SP-D can protect against allergic challenge via a range of mechanisms including inhibition...... of allergen-IgE interaction, histamine release by sensitised mast cells, downregulation of specific IgE production, suppression of pulmonary and peripheral eosinophilia, inhibition of mechanisms that cause airway remodelling, and induction of apoptosis in sensitised eosinophils. SP-D can also shift helper T...

  3. Citrobacter bitternis sp. nov. isolated from bitterns.

    Science.gov (United States)

    Ko, Kwan Soo; Choi, Ji-Young; Kim, Joo; Park, Myoung Kyu

    2015-06-01

    In this study, we reported two gram-negative bacteria that were isolated from bitterns, designated as SKKU-TP7(T) and SKKU-TP20, representing a novel species of Citrobacter. Based on the 16S rRNA gene sequences, the two strains were found to be closely related and showed the highest pairwise similarity with Citrobacter farmeri CDC 2992-81(T) (97.1-97.3 %) and other Citrobacter species. Cellular fatty acid analysis revealed that the profiles of strains SKKU-TP7(T) and SKKU-TP20 were similar to those of related species of Citrobacter. The major cellular fatty acids were C16:0 (31.5 %), summed feature 3 (C16:1 ω7c, C16:1 ω6c, 19.7 %), summed feature 8 (C18:1 ω7c, C18:1 ω6c, 11.9 %), C17:0 cyclo (10.7 %), and summed feature 2 (C12:0 aldehyde/unknown 10928, 9.5 %). Although the strains could utilize sucrose and raffinose as a carbon source, they did not produce ornithine decarboxylase and urease. The biochemical and genotypic characteristics indicate that strains SKKU-TP7(T) and SKKU-TP20 represent a novel species of Citrobacter, for which the name Citrobacter bitterns sp. nov. is proposed. The type strain is SKKU-TP7(T) (=KCTC 42139(T) = JCM 30009(T)).

  4. Accomplishments and plans of SP-100 program

    International Nuclear Information System (INIS)

    The SP-100 program is proceeding toward concept definitions for a space nuclear reactor which is safe and suitable for civilian and military applications. The selection of a specific design and demonstration of the base technologies was scheduled for the end of 1985, to be followed by engineering development and ground testing in 1986. The main current uses/users thus far anticipated are communications satellites, both military and civilian, radar (and possibly laser) surveillance and remote sensing systems, and manufacturing and other extensions of a space station growth scenario. The reactor will weigh no more than 3000 kg and must fit into the Orbiter bay with a payload and OTV. Three concepts are still under evaluation: a lithium-cooled reactor with thermoelectrics; an in-core thermionic system with pumped sodium-potassium coolant; and a configuration with a Stirling engine to convert reactor heat into electricity. If the engineering analyses and base tests are successful, it is expected that the flight application phase can be reached by 1991 at the latest

  5. Flavobacterium shanxiense sp. nov., isolated from soil.

    Science.gov (United States)

    Yang, Fan; Liu, Hong-Ming; Zhang, Rong; Chen, Ding-Bin; Wang, Xiang; Yan, Xin; Hong, Qing; Li, Shun-Peng

    2015-06-01

    Strain YF-2(T), a Gram-staining-negative, non-motile, non-spore-forming, light-yellow-pigmented bacterium, was isolated from soil samples collected in the city of Yuncheng, Shanxi province of China. Strain YF-2(T) grew over a temperature range of 25-37 °C, at pH 5.0-8.0 and with 0-5 % (w/v) NaCl. Phylogenetic analysis based on sequence of the 16S rRNA gene showed that strain YF-2(T) was closely related to strains Flavobacterium akiainvivens CIP 110358(T) and Flavobacterium hauense KCTC 32147(T) with 95.99 and 95.92 % sequence similarity, respectively. The dominant fatty acids of strain YF-2(T) were Summed Feature 3 (comprising C16:1 ω7c and/or C16:1 ω6c) (21.97 %), iso-C15:0 (18.65 %), iso-C17:0 3OH (11.41 %), C16:0 (9.92 %), and anteiso-C15:0 (6.21 %). It contained phosphatidylethanolamine and menaquinone MK-6 as major polar lipid and respiratory quinone, respectively. Strain YF-2(T) differs from other Flavobacterium species in many characteristics and represents a novel species, for which the name Flavobacterium shanxiense sp. nov. is proposed. The type strain is strain YF-2(T) (=CCTCC AB 2014079(T) = JCM 30153(T)). PMID:25726422

  6. Flavobacterium procerum sp. nov., isolated from freshwater.

    Science.gov (United States)

    Feng, Qingqing; Han, Lu; Yuan, Xin; Tan, Xu; Gao, Yuan; Lv, Jie

    2015-08-01

    A Gram-reaction-negative, strictly aerobic, yellow-pigmented, rod-shaped bacterium, designated strain T3T, was isolated from freshwater of Chishui River flowing through Maotai town, Guizhou, south-west China. Analysis of the16S rRNA gene sequence indicated that strain T3T was a member of the genus Flavobacterium and closely related to Flavobacterium resistens DSM 19382T (96.8 %). The novel strain was able to grow at 10-34 °C (optimum 28 °C), pH 6.0-11.0 (optimum pH 8.0-9.0) and with 0-2.0 % (w/v) NaCl (optimum 0 %). The major polar lipids were phosphatidylethanolamine, two unknown glycolipids, five unknown aminolipids and four unidentified lipids, and the major respiratory quinone was MK-6. The predominant fatty acids were C16  :  1ω7c and/or C16  :  1ω6c and iso-C15  :  0. The DNA G+C content of the strain was 36 mol  %. Based on these data, strain T3T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium procerum sp. nov. is proposed. The type strain is T3T ( = CGMCC 1.12926T = JCM 30113T). PMID:25969476

  7. Dokdonia pacifica sp. nov., isolated from seawater.

    Science.gov (United States)

    Zhang, Zenghu; Gao, Xin; Wang, Long; Zhang, Xiao-Hua

    2015-07-01

    A Gram-stain-negative, aerobic, non-flagellated, non-gliding, oxidase- and catalase-positive, rod-shaped, yellow-pigmented bacterium, designated strain SW230(T), was isolated from a surface seawater sample collected from the South Pacific Gyre. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SW230(T) shared highest similarity with members of the genus Dokdonia (95.0-94.5%), exhibiting 95.0% sequence similarity to Dokdonia genika NBRC 100811(T). Optimal growth occurred in the presence of 2-3% (w/v) NaCl, at pH 8.0 and at 28 °C. The DNA G+C content of strain SW230(T) was 36 mol%. The major fatty acids (>10% of the total) were iso-C15:1 G, iso-C15:0, iso-C17:0 3-OH, and C16:1 ω7c and/or C16:1ω6c. The major respiratory quinone was menaquinone-6. The major polar lipids were phosphatidylethanolamine, two unidentified aminolipids and two unidentified lipids. On the basis of data from the present polyphasic study, strain SW230(T) is considered to represent a novel species of the genus Dokdonia, for which the name Dokdonia pacifica sp. nov. is proposed. The type strain is SW230(T) ( = CGMCC 1.12184(T) = JCM 18216(T)). PMID:25862384

  8. Clostridium jejuense sp. nov., isolated from soil.

    Science.gov (United States)

    Jeong, Hyunyoung; Yi, Hana; Sekiguchi, Yuji; Muramatsu, Mizuho; Kamagata, Yoichi; Chun, Jongsik

    2004-09-01

    A strictly anaerobic, mesophilic, endospore-forming bacterium, designated strain HY-35-12T, was isolated from a soil sample in Jeju, Korea. Cells of this isolate were Gram-positive, motile rods that formed oval to spherical terminal spores. Strain HY-35-12T grew optimally at 30 degrees C, pH 7.0 and 0-0.5 % (w/v) NaCl. The isolate produced pyruvate, lactate, acetate, formate and hydrogen as fermentation end products from glucose. The G + C content of DNA of the isolate was 41 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the organism formed a monophyletic clade with Clostridium xylanovorans and Clostridium aminovalericum in cluster XIVa of the genus Clostridium. The closest phylogenetic neighbour was C. xylanovorans, with 96.65 % 16S rRNA gene sequence similarity. Several physiological and chemotaxonomic properties were identified that enable strain HY-35-12T to be distinguished from phylogenetically related clostridia. On the basis of polyphasic characteristics, it is proposed that strain HY-35-12T (= IMSNU 40003T = KCTC 5026T = DSM 15929T) represents a novel species, Clostridium jejuense sp. nov.

  9. Itinerant ferromagnetism in fermionic systems with SP (2 N) symmetry

    Science.gov (United States)

    Yang, Wang; Wu, Congjun

    The Ginzburg-Landau free energy of systems with SP (2 N) symmetry describes a second order phase transition on the mean field level, since the Casimir invariants of the SP (2 N) group can be only of even order combinations of the generators of the SP (2 N) group. This is in contrast with systems having the SU (N) symmetry, where the allowance of cubic term generally makes the phase transition into first order. In this work, we consider the Hertz-Millis type itinerant ferromagnetism in an interacting fermionic system with SP (2 N) symmetry, where the ferromagnetic orders are enriched by the multi-component nature of the system. The quantum criticality is discussed near the second order phase transition point.

  10. LEGACY - EOP Gold Coral (Gerardia sp.) Growth Measurements

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gold coral (Gerardia sp.) trees that were inspected years earlier on Pisces submersible dives were revisited and their change in size measured. The fishery for...

  11. Achelia shepherdi n. sp. and other Pycnogonida from Australia

    NARCIS (Netherlands)

    Stock, Jan H.

    1973-01-01

    Records of 10 species of shallow water Pycnogonida from Western Australia, Victoria, Tasmania, and New South Wales, including Achelia shepherdi n. sp., Parapallene avida Stock, 1973 (♀ new to science), and Anoplodactylus pulcher Carpenter, 1907 (new to Australia).

  12. Massarina armatispora sp. nov., a new intertidal ascomycete from mangroves

    Digital Repository Service at National Institute of Oceanography (India)

    Hyde, K.D.; Vrijmoed, L.L.P.; Chinnaraj, S.; Jones, E.B.G.

    Massarina armatispora sp. nov. is described from dead intertidal mangrove wood collected in India and Hong Kong. The new taxon is compared with other M. species, and its placement in the genus Massarina is discussed...

  13. Volvatellin, caulerpenyne-related product fromt he sacoglossan Volvatella sp.

    Digital Repository Service at National Institute of Oceanography (India)

    Fontana, A.; Ciavatta, M.L.; Mollo, E.; Naik, C.G.; Wahidullah, S.; DeSouza, L.; Cimino, G.

    Volvatellin (4) is a highly unstable terpene isolated from the extracts of the Indian opisthobranch mollusk Volvatella sp. The structure and the relative stereochemistry of 4 were determined by NMR methods. The paper also describes a hypothetical...

  14. Genome Sequence of the Soil Bacterium Janthinobacterium sp. KBS0711

    OpenAIRE

    Shoemaker, William R.; Muscarella, Mario E.; Lennon, Jay T

    2015-01-01

    We present a draft genome of Janthinobacterium sp. KBS0711 that was isolated from agricultural soil. The genome provides insight into the ecological strategies of this bacterium in free-living and host-associated environments.

  15. Metabolism of glyphosate in Pseudomonas sp. strain LBr.

    OpenAIRE

    Jacob, G S; Garbow, J.R.; Hallas, L E; Kimack, N M; Kishore, G M; Schaefer, J.

    1988-01-01

    Metabolism of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. strain LBr, a bacterium isolated from a glyphosate process waste stream, was examined by a combination of solid-state 13C nuclear magnetic resonance experiments and analysis of the phosphonate composition of the growth medium. Pseudomonas sp. strain LBr was capable of eliminating 20 mM glyphosate from the growth medium, an amount approximately 20-fold greater than that reported for any other microorganism to date. The bact...

  16. Sarcocystis sp. in the eastern cottontail (Sylvilagus floridanus).

    Science.gov (United States)

    Cosgrove, M; Wiggins, J P; Rothenbacher, H

    1982-01-01

    Sarcocystis sp. was observed in 100 of 185 (54.1%) Eastern cottontails (Sylvilagus floridanus) examined in Pennsylvania over a three year period. Gross and histologic examination commonly revealed cysts in skeletal muscle of the fore and hind legs, flanks and loins. Two rabbits had cysts in esophageal skeletal muscle. Host response to Sarcocystis sp. is described. Adult rabbits had a significantly greater rate of infection (69.3%) than juveniles (20.7%) (P less than 0.01). PMID:6808158

  17. Sp1 and p73 activate PUMA following serum starvation

    OpenAIRE

    Ming, Lihua; Sakaida, Tsukasa; Yue, Wen; Jha, Anupma; Zhang, Lin; Yu, Jian

    2008-01-01

    p53-upregulated modulator of apoptosis (PUMA) plays an essential role in p53-dependent apoptosis following DNA damage. PUMA also mediates apoptosis independent of p53. In this study, we investigated the role and mechanism of PUMA induction in response to serum starvation in p53-deficient cancer cells. Following serum starvation, the binding of Sp1 to the PUMA promoter significantly increased, whereas inhibition of Sp1 completely abrogated PUMA induction. p73 was found to be upregulated by ser...

  18. SP8 regulates signaling centers during craniofacial development.

    Science.gov (United States)

    Kasberg, Abigail D; Brunskill, Eric W; Steven Potter, S

    2013-09-15

    Much of the bone, cartilage and smooth muscle of the vertebrate face is derived from neural crest (NC) cells. During craniofacial development, the anterior neural ridge (ANR) and olfactory pit (OP) signaling centers are responsible for driving the outgrowth, survival, and differentiation of NC populated facial prominences, primarily via FGF. While much is known about the functional importance of signaling centers, relatively little is understood of how these signaling centers are made and maintained. In this report we describe a dramatic craniofacial malformation in mice mutant for the zinc finger transcription factor gene Sp8. At E14.5 they show facial prominences that are reduced in size and underdeveloped, giving an almost faceless phenotype. At later times they show severe midline defects, excencephaly, hyperterlorism, cleft palate, and a striking loss of many NC and paraxial mesoderm derived cranial bones. Sp8 expression was primarily restricted to the ANR and OP regions during craniofacial development. Analysis of an extensive series of conditional Sp8 mutants confirmed the critical role of Sp8 in signaling centers, and not directly in the NC and paraxial mesoderm cells. The NC cells of the Sp8 mutants showed increased levels of apoptosis and decreased cell proliferation, thereby explaining the reduced sizes of the facial prominences. Perturbed gene expression in the Sp8 mutants was examined by laser capture microdissection coupled with microarrays, as well as in situ hybridization and immunostaining. The most dramatic differences included striking reductions in Fgf8 and Fgf17 expression in the ANR and OP signaling centers. We were also able to achieve genetic and pharmaceutical partial rescue of the Sp8 mutant phenotype by reducing Sonic Hedgehog (SHH) signaling. These results show that Sp8 primarily functions to promote Fgf expression in the ANR and OP signaling centers that drive the survival, proliferation, and differentiation of the NC and paraxial

  19. Biodegradation of Para Amino Acetanilide by Halomonas sp. TBZ3

    OpenAIRE

    Hajizadeh, Nader; Sefidi Heris, Youssof; Zununi Vahed, Sepideh; Vallipour, Javad; Hejazi, Mohammad Amin; Golabi, Sayyed Mahdi; Asadpour-Zeynali, Karim; Hejazi, Mohammad Saeid

    2015-01-01

    Background: Aromatic compounds are known as a group of highly persistent environmental pollutants. Halomonas sp. TBZ3 was isolated from the highly salty Urmia Lake of Iran. In this study, characterization of a new Halomonas isolate called Halomonas sp. TBZ3 and its employment for biodegradation of para-amino acetanilide (PAA), as an aromatic environmental pollutant, is described. Objectives: This study aimed to characterize the TBZ3 isolate and to elucidate its ability as a biodegradative age...

  20. Three new Scandinavian species of Culicoides (Culicoides): Culicoides boyi sp. nov., Culicoides selandicus sp. nov. and Culicoides kalix sp. nov. (Diptera: Ceratopogonidae)

    Science.gov (United States)

    Kristensen, Michael; Pape, Thomas

    2015-01-01

    Abstract Background In the context of a major monitoring program of Culicoides in Denmark and Sweden due to the appearance of bluetongue disease in 2007–2008, a large number of specimens were collected by light traps and sorted morphologically, with COI barcodes generated for selected specimens. New information Three species are described as new to science based on both morphological and molecular data: Culicoides (Culicoides) boyi sp. nov. (Denmark: Jutland), C. (C.) selandicus sp. nov. (Denmark: Zealand) and C. (C.) kalix sp. nov. (Sweden: Norrbotten). All are diagnosed morphologically as well as by molecular barcoding. A key to slide-mounted females of all Scandinavian species of Culicoides (Culicoides) is presented. PMID:26696760

  1. New sequestrate fungi from Guyana: Jimtrappea guyanensis gen. sp. nov., Castellanea pakaraimophila gen. sp. nov., and Costatisporus cyanescens gen. sp. nov. (Boletaceae, Boletales).

    Science.gov (United States)

    Smith, Matthew E; Amses, Kevin R; Elliott, Todd F; Obase, Keisuke; Aime, M Catherine; Henkel, Terry W

    2015-12-01

    Jimtrappea guyanensis gen. sp. nov., Castellanea pakaraimophila gen. sp. nov., and Costatisporus cyanescens gen. sp. nov. are described as new to science. These sequestrate, hypogeous fungi were collected in Guyana under closed canopy tropical forests in association with ectomycorrhizal (ECM) host tree genera Dicymbe (Fabaceae subfam. Caesalpinioideae), Aldina (Fabaceae subfam. Papilionoideae), and Pakaraimaea (Dipterocarpaceae). Molecular data place these fungi in Boletaceae (Boletales, Agaricomycetes, Basidiomycota) and inform their relationships to other known epigeous and sequestrate taxa within that family. Macro- and micromorphological characters, habitat, and multi-locus DNA sequence data are provided for each new taxon. Unique morphological features and a molecular phylogenetic analysis of 185 taxa across the order Boletales justify the recognition of the three new genera. PMID:26732137

  2. Uranium and thorium uptake by live and dead cells of Pseudomonas Sp

    International Nuclear Information System (INIS)

    This study presents uptake of uranium (U) and thorium (Th) by live and dead cells of Pseudomonas Sp. Increasing concentration of U and Tb showed decrease in absorption by Pseudomonas Sp. Dead cells of Pseudomonas Sp. exhibited same or more uptake of U and Th than living cells. Increasing temperature promotes uptake of U and Th by Pseudomonas Sp. (author)

  3. SpIES: The Spitzer IRAC Equatorial Survey

    CERN Document Server

    Timlin, John D; Richards, Gordon T; Lacy, Mark; Ryan, Erin L; Stone, Robert B; Bauer, Franz E; Brandt, W N; Fan, Xiaohui; Glikman, Eilat; Haggard, Daryl; Jiang, Linhua; LaMassa, Stephanie M; Lin, Yen-Ting; Makler, Martin; McGehee, Peregrine; Myers, Adam D; Schneider, Donald P; Urry, C Megan; Wollack, Edward J; Zakamska, Nadia L

    2016-01-01

    We describe the first data release from the Spitzer-IRAC Equatorial Survey (SpIES); a large-area survey of 115 deg^2 in the Equatorial SDSS Stripe 82 field using Spitzer during its 'warm' mission phase. SpIES was designed to probe sufficient volume to perform measurements of quasar clustering and the luminosity function at z > 3 to test various models for "feedback" from active galactic nuclei (AGN). Additionally, the wide range of available multi-wavelength, multi-epoch ancillary data enables SpIES to identify both high-redshift (z > 5) quasars as well as obscured quasars missed by optical surveys. SpIES achieves 5{\\sigma} depths of 6.13 {\\mu}Jy (21.93 AB magnitude) and 5.75 {\\mu}Jy (22.0 AB magnitude) at 3.6 and 4.5 microns, respectively - depths significantly fainter than WISE. We show that the SpIES survey recovers a much larger fraction of spectroscopically-confirmed quasars (98%) in Stripe 82 than are recovered by WISE (55%). This depth is especially powerful at high-redshift (z > 3.5), where SpIES reco...

  4. Pin1-mediated Sp1 phosphorylation by CDK1 increases Sp1 stability and decreases its DNA-binding activity during mitosis.

    Science.gov (United States)

    Yang, Hang-Che; Chuang, Jian-Ying; Jeng, Wen-Yih; Liu, Chia-I; Wang, Andrew H-J; Lu, Pei-Jung; Chang, Wen-Chang; Hung, Jan-Jong

    2014-12-16

    We have shown that Sp1 phosphorylation at Thr739 decreases its DNA-binding activity. In this study, we found that phosphorylation of Sp1 at Thr739 alone is necessary, but not sufficient for the inhibition of its DNA-binding activity during mitosis. We demonstrated that Pin1 could be recruited to the Thr739(p)-Pro motif of Sp1 to modulate the interaction between phospho-Sp1 and CDK1, thereby facilitating CDK1-mediated phosphorylation of Sp1 at Ser720, Thr723 and Thr737 during mitosis. Loss of the C-terminal end of Sp1 (amino acids 741-785) significantly increased Sp1 phosphorylation, implying that the C-terminus inhibits CDK1-mediated Sp1 phosphorylation. Binding analysis of Sp1 peptides to Pin1 by isothermal titration calorimetry indicated that Pin1 interacts with Thr739(p)-Sp1 peptide but not with Thr739-Sp1 peptide. X-ray crystallography data showed that the Thr739(p)-Sp1 peptide occupies the active site of Pin1. Increased Sp1 phosphorylation by CDK1 during mitosis not only stabilized Sp1 levels by decreasing interaction with ubiquitin E3-ligase RNF4 but also caused Sp1 to move out of the chromosomes completely by decreasing its DNA-binding activity, thereby facilitating cell cycle progression. Thus, Pin1-mediated conformational changes in the C-terminal region of Sp1 are critical for increased CDK1-mediated Sp1 phosphorylation to facilitate cell cycle progression during mitosis.

  5. GLUT1 glucose transporter gene transcription is repressed by Sp3. Evidence for a regulatory role of Sp3 during myogenesis.

    Science.gov (United States)

    Fandos, C; Sánchez-Feutrie, M; Santalucía, T; Viñals, F; Cadefau, J; Gumà, A; Cussó, R; Kaliman, P; Canicio, J; Palacín, M; Zorzano, A

    1999-11-19

    GLUT1 glucose transporters are highly expressed in proliferating and transformed cells as well as in tissues during fetal life. However, the mechanisms that regulate GLUT1 gene expression remain largely unknown. Here, we demonstrate that Sp3 proteins bind to the GLUT1 proximal promoter gene and inhibit transcriptional activity in muscle and non-muscle cells. Two different Sp3 translational products (110 and 74 kDa) derived from differential translational initiation were detected in nuclear extracts from myoblast cells, and both Sp3 protein species inhibited GLUT1 gene transcriptional activity. The inhibitory effect of Sp3 was dominant over the stimulatory effect of Sp1 on transcriptional activity of GLUT1 gene. Furthermore, abolition of Sp3 binding to the proximal promoter of GLUT1 gene completely blocked the response to Sp3. We provide evidence that the expression of Sp3 protein is subject to regulation in muscle cells and that this is likely to control GLUT1. Thus, Sp3 protein was up-regulated in the absence of changes in Sp1 early after the induction of IGF-II-dependent myogenesis. Furthermore, forced over-expression of MyoD caused an enhancement in the cellular Sp3/Sp1 ratio which was concomitant to a reduced GLUT1 expression. Later during myogenesis, Sp3 expression was substantial whereas Sp1 was markedly down-regulated. In summary, we provide direct evidence that the transcription factor Sp3 represses gene expression in non-muscle and muscle cells and this is likely to operate in fetal heart by binding to the GLUT1 gene promoter. This is the first description of a repressor of GLUT1 gene transcription. Furthermore, we propose that variations in the ratio of Sp3 versus Sp1 regulate GLUT1 promoter activity and this is crucial in the down-regulation of GLUT1 associated to myogenesis. PMID:10556032

  6. Listeria booriae sp. nov. and Listeria newyorkensis sp. nov., from food processing environments in the USA.

    Science.gov (United States)

    Weller, Daniel; Andrus, Alexis; Wiedmann, Martin; den Bakker, Henk C

    2015-01-01

    Sampling of seafood and dairy processing facilities in the north-eastern USA produced 18 isolates of Listeria spp. that could not be identified at the species-level using traditional phenotypic and genotypic identification methods. Results of phenotypic and genotypic analyses suggested that the isolates represent two novel species with an average nucleotide blast identity of less than 92% with previously described species of the genus Listeria. Phylogenetic analyses based on whole genome sequences, 16S rRNA gene and sigB gene sequences confirmed that the isolates represented by type strain FSL M6-0635(T) and FSL A5-0209 cluster phylogenetically with Listeria cornellensis. Phylogenetic analyses also showed that the isolates represented by type strain FSL A5-0281(T) cluster phylogenetically with Listeria riparia. The name Listeria booriae sp. nov. is proposed for the species represented by type strain FSL A5-0281(T) ( =DSM 28860(T) =LMG 28311(T)), and the name Listeria newyorkensis sp. nov. is proposed for the species represented by type strain FSL M6-0635(T) ( =DSM 28861(T) =LMG 28310(T)). Phenotypic and genotypic analyses suggest that neither species is pathogenic.

  7. Potencial de antagonismo de isolados de Trichoderma sp. contra o isolados de Fusarium sp., in vitro

    Directory of Open Access Journals (Sweden)

    Charles Anthony Hoffmann

    2015-06-01

    Full Text Available Resumo – O uso discriminado de agrotóxicos acarreta em uma grande prejuízo a saúdes das pessoas e do meio ambiente. O uso de novos métodos de combate a pragas se faz necessário para o equilíbrio da cadeia produtiva. A utilização de microrganismos no combate a pragas se faz como uma boa alternativa. O trabalho objetivou-se em avaliar o potencial de antagonismo de isolados de Trichoderma sp. contra o patógeno Fusarium sp. in vitro. Para isso foi utilizado os métodos de confronto direto, pareamento de culturas e de metabólitos voláteis. Os experimentos foram realizados na incubadora de empresas da Universidade Federal do Tocantins – UFT Campus de Gurupi, seguiram com três repetições. Foram testados 15 isolados do antagonista em confronto direto com o patógeno e os mesmos isolados e patógeno foram testados em metabólitos voláteis ambos utilizando o meio de cultura BDA. Todos os isolados apresentaram antagonismo in vitro contra o patógeno.

  8. Vibrio hispanicus sp. nov., isolated from Artemia sp. and sea water in Spain.

    Science.gov (United States)

    Gomez-Gil, B; Thompson, F L; Thompson, C C; Garcia-Gasca, A; Roque, A; Swings, J

    2004-01-01

    Three Gram-negative, small, motile, rod-shaped bacteria were isolated from Artemia sp. and sea water in Barcelona, Spain, during 1990 and 1991. They were fermentative, oxidase-positive, sensitive to vibriostatic agent O/129, arginine dihydrolase-positive, lysine and ornithine decarboxylase-negative and grew in the absence of NaCl. They differed from phenotypically related species by their ability to grow at 4 degrees C and utilize L-rhamnose. Cloning of the 16S rRNA gene of the type strain produced two different 16S rRNA gene sequences, which differed by 15 bases (0.99%); comparison of these sequences with those deposited in GenBank showed close relationships with Vibrio proteolyticus (97.6% similarity), Vibrio diazotrophicus (97.9%), Vibrio campbellii (96.8%) and Vibrio alginolyticus (96.8%), among others. DNA-DNA hybridization levels with the closest phylogenetically related Vibrio species were Vibrio, for which the name Vibrio hispanicus sp. nov. is proposed, with the type strain LMG 13240T (=CAIM 525T=VIB 213T).

  9. Aquamicrobium ahrensii sp. nov. and Aquamicrobium segne sp. nov., isolated from experimental biofilters.

    Science.gov (United States)

    Lipski, André; Kämpfer, Peter

    2012-10-01

    Two groups of Gram-negative, aerobic bacterial strains previously isolated from experimental biofilters were investigated to determine their taxonomic position. Based on their 16S rRNA gene sequences, these isolates formed two distinct groups within the genus Aquamicrobium. The gene sequence similarities of the new isolates to the type strains of Aquamicrobium species were below 98.3 %. The presence of ubiquinone-10, C(18 : 1) cis 11 as the predominant fatty acid and a polar lipid pattern with phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol and phosphatidylethanolamine was in accordance with the characteristics of this genus. The results of DNA-DNA hybridization, biochemical tests and chemotaxonomic properties allowed genotypic and phenotypic differentiation of the strains from all recognized species of the genus Aquamicrobium. Therefore, the isolates were assigned to two novel species of this genus for which the names Aquamicrobium ahrensii sp. nov. (type strain 905/1(T) = DSM 19730(T) = CCUG 55251(T)) and Aquamicrobium segne sp. nov. (type strain 1006/1(T) = DSM 19714(T) = CCUG 55250(T)) are proposed. An emended description of the genus Aquamicrobium is also presented.

  10. Lactobacillus plajomi sp. nov. and Lactobacillus modestisalitolerans sp. nov., isolated from traditional fermented foods.

    Science.gov (United States)

    Miyashita, Mika; Yukphan, Pattaraporn; Chaipitakchonlatarn, Winai; Malimas, Taweesak; Sugimoto, Masako; Yoshino, Mayumi; Kamakura, Yuki; Potacharoen, Wanchern; Tanasupawat, Somboon; Tanaka, Naoto; Nakagawa, Yasuyoshi; Suzuki, Ken-ichiro

    2015-08-01

    Three Lactobacillus-like strains, NB53T, NB446T and NB702, were isolated from traditional fermented food in Thailand. Comparative 16S rRNA gene sequence analysis indicated that these strains belong to the Lactobacillus plantarum group. Phylogenetic analysis based on the dnaK, rpoA, pheS and recA gene sequences indicated that these three strains were distantly related to known species present in the L. plantarum group. DNA-DNA hybridization with closely related strains demonstrated that these strains represented two novel species; the novel strains could be differentiated based on chemotaxonomic and phenotypic characteristics. Therefore, two novel species of the genus Lactobacillus, Lactobacillus plajomi sp. nov. (NB53T) and Lactobacillus modestisalitolerans sp. nov. (NB446T and NB702), are proposed with the type strains NB53T ( = NBRC 107333T = BCC 38054T) and NB446T ( = NBRC 107235T = BCC 38191T), respectively.

  11. Characterization of a Bioflocculant Produced by a Consortium of Halomonas sp. Okoh and Micrococcus sp. Leo

    Directory of Open Access Journals (Sweden)

    Anthony I. Okoh

    2013-10-01

    Full Text Available The physicochemical and flocculating properties of a bioflocculant produced by a bacterial consortium composed of Halomonas sp. Okoh and Micrococcus sp. Leo were investigated. The purified bioflocculant was cation and pH dependent, and optimally flocculated kaolin clay suspension at a dosage of 0.1 mg/mL. The flocculating activity of the bioflocculant was stimulated in the presence of Ca2+, Mn2+, Al3+ and had a wide pH range of 2–10, with the highest flocculating activity of 86% at pH 8. The bioflocculant was thermostable and retained more than 70% of its flocculating activity after being heated at 80 °C for 30 min. Thermogravimetric analyses revealed a partial thermal decomposition of the biofloculant at 400 °C. The infrared spectrum showed the presence of hydroxyl, carboxyl and amino moieties as functional groups. The bioflocculant produced by the bacterial consortium appears to hold promising alternative to inorganic and synthetic organic flocculants that are widely used in wastewater treatment.

  12. Novel application of Mahua (Madhuca sp.) flowers for augmented protease production from Aeromonas sp. S1.

    Science.gov (United States)

    Bhattacharya, Amrik; Saini, Vandana; Gupta, Anshu

    2012-10-01

    The present study explored the utilization of Mahua (Madhuca sp.) flowers, a major non-timber forest product (NTFP) of India, as a low-cost, natural substrate for protease production under submerged fermentation. Bacterial strain Aeromonas sp. Si1, previously reported by us, was used as the protease producer. Using Mahua flower extract (MFE) as the medium additive, the protease production could successfully be enhanced by 5.6-fold (564.5 UmL-1) after 24 h of fermentation under optimized conditions compared with initial production of 99.9 UmL' in the absence of MFE. The cultural parameters for optimum production of protease were determined to be: incubation time-24 h; pH-7.0; MFE concentration-5% (v/v); inoculum size-0.3% (v/v) and agitation rate-200 rpm. The results obtained demonstrate the potential of cheaper and abundantly available Mahua flowers for induction of proteases, and thus offer a new approach for value addition to this biomass through industrial enzyme production. PMID:23157010

  13. Sur la présence d’Echinogammarus du groupe pungens au Liban: E. berytensis n. sp., E. tripoliensis n. sp. et E. rashiini n. sp. (Crustacea, Amphipoda)

    NARCIS (Netherlands)

    Alouf, N.J.

    1976-01-01

    Description of three fresh-water species of Echinogammarus: E. berytensis n. sp. from the center of Lebanon near Beirut, E. tripoliensis n. sp. and E. rashiini n. sp. from the North of the country near Tripoli. The first two species are related; the second one has some features of the E. simoni-grou

  14. Genomic analysis and D-xylose fermentation of three novel Spathaspora species: Spathaspora girioi sp. nov., Spathaspora hagerdaliae f. a., sp. nov. and Spathaspora gorwiae f. a., sp. nov.

    Science.gov (United States)

    Lopes, Mariana R; Morais, Camila G; Kominek, Jacek; Cadete, Raquel M; Soares, Marco A; Uetanabaro, Ana Paula T; Fonseca, César; Lachance, Marc-André; Hittinger, Chris Todd; Rosa, Carlos A

    2016-06-01

    Three novel D-xylose-fermenting yeast species of Spathaspora clade were recovered from rotting wood in regions of the Atlantic Rainforest ecosystem in Brazil. Differentiation of new species was based on analyses of the gene encoding the D1/D2 sequences of large subunit of rRNA and on 642 conserved, single-copy, orthologous genes from genome sequence assemblies from the newly described species and 15 closely-related Debaryomycetaceae/Metschnikowiaceae species. Spathaspora girioi sp. nov. produced unconjugated asci with a single elongated ascospore with curved ends; ascospore formation was not observed for the other two species. The three novel species ferment D-xylose with different efficiencies. Spathaspora hagerdaliae sp. nov. and Sp. girioi sp. nov. showed xylose reductase (XR) activity strictly dependent on NADPH, whereas Sp. gorwiae sp. nov. had XR activity that used both NADH and NADPH as co-factors. The genes that encode enzymes involved in D-xylose metabolism (XR, xylitol dehydrogenase and xylulokinase) were also identified for these novel species. The type strains are Sp. girioi sp. nov. UFMG-CM-Y302(T) (=CBS 13476), Sp. hagerdaliae f.a., sp. nov. UFMG-CM-Y303(T) (=CBS 13475) and Sp. gorwiae f.a., sp. nov. UFMG-CM-Y312(T) (=CBS 13472). PMID:27188884

  15. Magnetospirillum caucaseum sp. nov., Magnetospirillum marisnigri sp. nov. and Magnetospirillum moscoviense sp. nov., freshwater magnetotactic bacteria isolated from three distinct geographical locations in European Russia.

    Science.gov (United States)

    Dziuba, Marina; Koziaeva, Veronika; Grouzdev, Denis; Burganskaya, Ekaterina; Baslerov, Roman; Kolganova, Tatjana; Chernyadyev, Alexander; Osipov, Georgy; Andrianova, Ekaterina; Gorlenko, Vladimir; Kuznetsov, Boris

    2016-05-01

    Three strains of helical, magnetotactic bacteria, SO-1T, SP-1T and BB-1T, were isolated from freshwater sediments collected from three distinct locations in European Russia. Phylogenetic analysis showed that the strains belong to the genus Magnetospirillum. Strains SO-1T and SP-1T showed the highest 16S rRNA gene sequence similarity to Magnetospirillum magnetotacticum MS-1T (99.3 and 98.1 %, respectively), and strain BB-1T with Magnetospirillum gryphiswaldense MSR-1T (97.3 %). The tree based on concatenated deduced amino acid sequences of the MamA, B, K, M, O, P, Q and T proteins, which are involved in magnetosome formation, was congruent with the tree based on 16S rRNA gene sequences. The genomic DNA G+C contents of strains SO-1T, SP-1T and BB-1T were 65.9, 63.0 and 65.2 mol%, respectively. As major fatty acids, C18 : 1ω9, C16 : 1ω7c, C16 : 0 and C18 : 0 were detected. DNA-DNA hybridization values between the novel strains and their closest relatives in the genus Magnetospirillum were less than 51.7 ± 2.3 %. In contrast to M. magnetotacticum MS-1T, the strains could utilize butyrate and propionate; strains SO-1T and BB-1T could also utilize glycerol. Strain SP-1T showed strictly microaerophilic growth, whereas strains SO-1T and BB-1T were more tolerant of oxygen. The results of DNA-DNA hybridization and physiological tests allowed genotypic and phenotypic differentiation of the strains from each other as well as from the two species of Magnetospirillum with validly published names. Therefore, the strains represent novel species, for which we propose the names Magnetospirillum caucaseum sp. nov. (type strain SO-1T = DSM 28995T = VKM B-2936T), Magnetospirillum marisnigri sp. nov. (type strain SP-1T = DSM 29006T = VKM B-2938T) and Magnetospirillum moscoviense sp. nov. (type strain BB-1T = DSM 29455T = VKM B-2939T). PMID:26921147

  16. sp(2)-sp(3) diboranes: astounding structural variability and mild sources of nucleophilic boron for organic synthesis.

    Science.gov (United States)

    Dewhurst, Rian D; Neeve, Emily C; Braunschweig, Holger; Marder, Todd B

    2015-06-14

    Despite the widespread use of organoborane reagents in organic synthesis and catalysis, a major challenge still remains: very few boron-centered nucleophiles exist for the direct construction of B-C bonds. Perhaps the most promising emerging solution to this problem is the use of sp(2)-sp(3) diboranes, in which one boron atom of a conventional diborane(4) is quaternised by either a neutral or anionic nucleophile. These compounds, either isolated or generated in situ, serve as relatively mild and convenient sources of the boryl anion [BR2](-) for use in organic synthesis and have already proven their efficacy in metal-free as well as metal-catalysed borylation reactions. This Feature article documents the history of sp(2)-sp(3) diborane synthesis, their properties and surprising structural variability, and their burgeoning utility in organic synthesis.

  17. Rhopalophthalmus constrictus sp. nov. and Australomysis reubeni sp. nov. (Crustacea-Mysidacea) from south-west Australian waters

    Digital Repository Service at National Institute of Oceanography (India)

    Panampunnayil, S.U.

    Two new species of mysids are described, Rhopalophthalmus constrictus sp. nov. is in having a well-produced triangular rostral plate, pleural plates on the anterior five abdominal somites and prominent constriction at the distal end of the telson...

  18. Co-infection of the Siberian hamster (Phodopus sungorus) with a novel Helicobacter sp. and Campylobacter sp.

    Science.gov (United States)

    Nagamine, Claude M; Shen, Zeli; Luong, Richard H; McKeon, Gabriel P; Ruby, Norman F; Fox, James G

    2015-05-01

    We report the isolation of a novel helicobacter isolated from the caecum of the Siberian hamster (Phodopus sungorus). Sequence analysis showed 97% sequence similarity to Helicobacter ganmani. In addition, we report the co-infection of these Siberian hamsters with a Campylobacter sp. and a second Helicobacter sp. with 99% sequence similarity to Helicobacter sp. flexispira taxon 8 (Helicobacter bilis), a species isolated previously from patients with bacteraemia. Gross necropsy and histopathology did not reveal any overt pathological lesions of the liver and gastrointestinal tract that could be attributed to the Helicobacter or Campylobacter spp. infections. This is the first helicobacter to be identified in the Siberian hamster and the first report of co-infection of Helicobacter spp. and Campylobacter sp. in asymptomatic Siberian hamsters.

  19. Listeria fleischmannii sp. nov., isolated from cheese.

    Science.gov (United States)

    Bertsch, David; Rau, Jörg; Eugster, Marcel R; Haug, Martina C; Lawson, Paul A; Lacroix, Christophe; Meile, Leo

    2013-02-01

    A study was performed on three isolates (LU2006-1(T), LU2006-2 and LU2006-3), which were sampled independently from cheese in western Switzerland in 2006, as well as a fourth isolate (A11-3426), which was detected in 2011, using a polyphasic approach. The isolates could all be assigned to the genus Listeria but not to any known species. Phenotypic and chemotaxonomic data were compatible with the genus Listeria and phylogenetic analysis based on 16S rRNA gene sequences confirmed that the closest relationships were with members of this genus. However, DNA-DNA hybridization demonstrated that the isolates did not belong to any currently described species. Cell-wall-binding domains of Listeria monocytogenes bacteriophage endolysins were able to attach to the isolates, confirming their tight relatedness to the genus Listeria. Although PCR targeting the central portion of the flagellin gene flaA was positive, motility was not observed. The four isolates could not be discriminated by Fourier transform infrared spectroscopy or pulsed-field gel electrophoresis. This suggests that they represent a single species, which seems to be adapted to the environment in a cheese-ripening cellar as it was re-isolated from the same type of Swiss cheese after more than 5 years. Conjugation experiments demonstrated that the isolates harbour a transferable resistance to clindamycin. The isolates did not exhibit haemolysis or show any indication of human pathogenicity or virulence. The four isolates are affiliated with the genus Listeria but can be differentiated from all described members of the genus Listeria and therefore they merit being classified as representatives of a novel species, for which we propose the name Listeria fleischmannii sp. nov.; the type strain is LU2006-1(T) ( = DSM 24998(T)  = LMG 26584(T)).

  20. Belliella marina sp. nov., isolated from seawater.

    Science.gov (United States)

    Song, Lei; Liu, Hongcan; Wang, Jian; Huang, Ying; Dai, Xin; Han, Xiqiu; Zhou, Yuguang

    2015-12-01

    Gram-stain-negative, rod-shaped bacterium, strain SW112T, was isolated from a seawater sample collected from the Indian Ocean. The strain was strictly aerobic and catalase- and oxidase-positive. Strain SW112T grew at 4-42 °C (optimum 30 °C), at pH 5.5-9.5 (optimum pH 7.5) and in the presence of 0-9.0 % (w/v) NaCl (optimum 2.0-3.0 %). The predominant cellular fatty acids were iso-C15 : 0 (29.7 %), iso-C17 : 03-OH (14.3 %) and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c, 15.1 %). The major menaquinone was menaquinone-7 and the major polar lipid was phosphatidylethanolamine. The genomic DNA G+C content of strain SW112T was 39 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain SW112T was related to members of the genus Belliella, showing the highest similarity with Belliella aquatica TS-T86T and Belliella baltica DSM 15883T (96.5 % and 96.4 %sequence similarity, respectively). On the basis of phylogenetic inference and phenotypic characteristics, it is proposed that strain SW112T represents a novel species of the genus Belliella, for which the name Belliella marina sp. nov. is proposed. The type strain is SW112T(=CGMCC 1.15180T=KCTC 33694T). PMID:26346194

  1. Noviherbaspirillum humi sp. nov., isolated from soil.

    Science.gov (United States)

    Sundararaman, Aravind; Srinivasan, Sathiyaraj; Lee, Sang-Seob

    2016-05-01

    Two novel Gram-stain negative, motile, non-spore forming, facultative aerobic and short rod shaped bacterial strains, designated U15(T) and U32, were isolated from soil obtained from Ukraine. The sequence similarity of the 16S rRNA gene between strains U15(T) and U32 was found to be 99.5 %. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that new bacteria belong to the genus Noviherbaspirillum. The closest member of the genus was found to be Noviherbaspirillum malthae (97.0 %) followed by Noviherbaspirillum suwonensis (96.3 %). The novel isolates was observed to grow optimally at 30 °C and pH 7.0. The major fatty acids present in the two strains were identified as summed feature 3 (C16:1 ω7c/C16:1 ω6c), C16:0, and summed feature 8 (C18:1 ω7c/C18:1 ω6c). Ubiquinone 8 was identified as the respiratory quinone component for both the strains. The polar lipid (L) profile contained phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, aminophospholipid, unidentified aminolipid and unidentified Ls, and putrescine and 2-hydroxyputrescine as major polyamines. The G+C content of the DNA for the strain U15(T) was found to be 61.2 mol%. The DNA-DNA relatedness between U15(T) and U32 and closely related species was less than 40 %. Based on the polyphasic taxonomic analysis, a new species, Noviherbaspirillum humi sp. nov., is proposed. The type strain is strain U15(T) = JCM 19873(T) = KEMB 7305-102(T). PMID:26940744

  2. Streptomyces andamanensis sp. nov., isolated from soil.

    Science.gov (United States)

    Sripreechasak, Paranee; Tamura, Tomohiko; Shibata, Chiyo; Suwanborirux, Khanit; Tanasupawat, Somboon

    2016-05-01

    A novel actinomycete, strain KC-112T, was isolated from soil collected from Similan Islands, Phang-Nga Province, Thailand. The strain exhibited morphological and chemotaxonomic characteristics consistent with those of members of the genus Streptomyces. The formation of smooth spiral spore chains was observed on aerial mycelia. ll-Diaminopimelic acid was detected in whole-cell hydrolysates, but no diagnostic sugars were detected and the strain lacked mycolic acids. The N-acyl type of muramic acid was acetyl. The major menaquinones were MK-9(H8), MK-9(H6) and MK-9(H2). The predominant cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0 and C16 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, an unknown phospholipid, an unknown aminolipid, unknown lipids and an unknown glycolipid. The DNA G+C content was 73 mol%. On the basis of 16S rRNA gene sequence analysis, strain KC-112T was closely related to Streptomyces fumanus NBRC 13042T (98.8 % 16S rRNA gene sequence similarity), Streptomyces anandii NBRC 13438T (98.8 %) and Streptomyces capillispiralis NBRC 14222T (98.8 %). DNA-DNA relatedness values among strain KC-112T and type strains of closely related species were lower than 70 %. On the basis of evidence from this taxonomic study using a polyphasic approach, strain KC-112T represents a novel species of the genus Streptomyces, namely Streptomyces andamanensis sp. nov. The type strain is KC-112T ( = KCTC 29502T = NBRC 110085T = PCU 347T = TISTR 2401T). PMID:26908169

  3. Deinococcus antarcticus sp. nov., isolated from soil.

    Science.gov (United States)

    Dong, Ning; Li, Hui-Rong; Yuan, Meng; Zhang, Xiao-Hua; Yu, Yong

    2015-02-01

    A pink-pigmented, non-motile, coccoid bacterial strain, designated G3-6-20(T), was isolated from a soil sample collected in the Grove Mountains, East Antarctica. This strain was resistant to UV irradiation (810 J m(-2)) and slightly more sensitive to desiccation as compared with Deinococcus radiodurans. Phylogenetic analyses based on the 16S rRNA gene sequence of the isolate indicated that the organism belongs to the genus Deinococcus. Highest sequence similarities were with Deinococcus ficus CC-FR2-10(T) (93.5 %), Deinococcus xinjiangensis X-82(T) (92.8 %), Deinococcus indicus Wt/1a(T) (92.5 %), Deinococcus daejeonensis MJ27(T) (92.3 %), Deinococcus wulumuqiensis R-12(T) (92.3 %), Deinococcus aquaticus PB314(T) (92.2 %) and Deinococcus radiodurans DSM 20539(T) (92.2 %). Major fatty acids were C18 : 1ω7c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), anteiso-C15 : 0 and C16 : 0. The G+C content of the genomic DNA of strain G3-6-20(T) was 63.1 mol%. Menaquinone 8 (MK-8) was the predominant respiratory quinone. Based on its phylogenetic position, and chemotaxonomic and phenotypic characteristics, strain G3-6-20(T) represents a novel species of the genus Deinococcus, for which the name Deinococcus antarcticus sp. nov. is proposed. The type strain is G3-6-20(T) ( = DSM 27864(T) = CCTCC AB 2013263(T)). PMID:25351880

  4. Morfologia da laringe de cutia (Dasyprocta sp.

    Directory of Open Access Journals (Sweden)

    Andrezza B.S. Silva

    2014-06-01

    Full Text Available A cutia (Dasyprocta sp. é um roedor silvestre com distribuição mundial. Atualmente, além de importante papel ecológico que exerce, está sendo utilizada como modelo em experimento animal. Estudos sobre a morfologia destes animais são importantes porque podem ser uma alternativa para o estudo de diversos processos patológicos, além de contribuirem para a preservação da espécie. A laringe é um órgão localizado entre a faringe e a traqueia, no qual está envolvido nas funções de respiração, deglutição e fonação. O presente estudo propôs realizar uma descrição morfológica macroscópica e microscópica da laringe da cutia. Para tanto, foram utilizadas quinze cutias pertencentes ao Centro de Ciências Agrárias da Universidade Federal do Piauí e provenientes do Núcleo de Estudos e Preservação de Animais Silvestres com licença do IBAMA (Nº 02/08-618, CTF Nº 474064. Todos os animais foram identificados, promovida a sexagem e, posteriormente, a laringe acessada e dissecada sendo os fragmentos cartilagíneos encaminhados para rotina histológica e corados pelo método de hematoxilina-eosina. As lâminas obtidas foram visualizadas em microscopia óptica de luz e foto documentadas. A laringe da cutia apresenta cinco cartilagens, com ausência da cartilagem cuneiforme e presença da incisura caudal na cartilagem tireoide. O tecido epitelial da laringe varia de epitélio estratificado pavimentoso queratinizado à não queratinizado e ciliado com células caliciformes.

  5. Deinococcus antarcticus sp. nov., isolated from soil.

    Science.gov (United States)

    Dong, Ning; Li, Hui-Rong; Yuan, Meng; Zhang, Xiao-Hua; Yu, Yong

    2015-02-01

    A pink-pigmented, non-motile, coccoid bacterial strain, designated G3-6-20(T), was isolated from a soil sample collected in the Grove Mountains, East Antarctica. This strain was resistant to UV irradiation (810 J m(-2)) and slightly more sensitive to desiccation as compared with Deinococcus radiodurans. Phylogenetic analyses based on the 16S rRNA gene sequence of the isolate indicated that the organism belongs to the genus Deinococcus. Highest sequence similarities were with Deinococcus ficus CC-FR2-10(T) (93.5 %), Deinococcus xinjiangensis X-82(T) (92.8 %), Deinococcus indicus Wt/1a(T) (92.5 %), Deinococcus daejeonensis MJ27(T) (92.3 %), Deinococcus wulumuqiensis R-12(T) (92.3 %), Deinococcus aquaticus PB314(T) (92.2 %) and Deinococcus radiodurans DSM 20539(T) (92.2 %). Major fatty acids were C18 : 1ω7c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), anteiso-C15 : 0 and C16 : 0. The G+C content of the genomic DNA of strain G3-6-20(T) was 63.1 mol%. Menaquinone 8 (MK-8) was the predominant respiratory quinone. Based on its phylogenetic position, and chemotaxonomic and phenotypic characteristics, strain G3-6-20(T) represents a novel species of the genus Deinococcus, for which the name Deinococcus antarcticus sp. nov. is proposed. The type strain is G3-6-20(T) ( = DSM 27864(T) = CCTCC AB 2013263(T)).

  6. Effectiveness of measurements of serum KL-6, SP-A, and SP-D in the diagnosis of radiation pneumonitis

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Koichi; Nishiwaki, Yutaka [National Cancer Center, Kashiwa, Chiba (Japan). East Hospital; Yokoyama, Akira [Niigata Cancer Center (Japan); Mori, Kiyoshi [Tochigi Cancer Center (Japan); Watanabe, Koshiro [Yokohama City Hospital (Japan); Saijo, Osahiro [National Cancer Center, Tokyo (Japan). Hospital

    2002-02-01

    The authors prospectively assessed the effectiveness of measuring serum concentrations of 3 markers, KL-6, surfactant protein-A (SP-A), and surfactant protein-D (SP-D), in the diagnosis of radiation pneumonitis. The subjects were 127 patients (102 men, 25 women; mean age; 67 years; 123 with lung cancer and 4 with mediastinal tumors). The patients were irradiated with 10-80 Gy (mean dose, 55.3 Gy), and combination chemotherapy was administered to 96 patients. Blood samples were collected weekly during radiotherapy, and every 2 weeks for 4 months after radiotherapy. KL-6, SP-A, and SP-D were measured in the serum samples obtained. None of the markers tended to increase in any of the 35 patients not diagnosed with radiation pneumonitis. Limited radiation pneumonitis occurred in 84 patients, and severe pneumonitis beyond the radiation field developed in 8 patients. In the severe pneumonitis patients, all of the markers clearly tended to increase before and after the crisis of the pneumonitis. In the severe pneumonitis patients, the maximum serum marker values increased to {>=}3 fold the level of KL-6, {>=}4 fold the level of SP-D, and {>=}2 fold the level of SP-A, more than in the limited pneumonitis patients. Until now radiation pneumonitis has been mainly diagnosed by imaging, however, measuring the serum concentrations of the markers KL-6, SP-A, and SP-D, in addition to diagnostic imaging, will enable more accurate and rapid diagnosis of severe pneumonitis than before. These markers also seem to be useful indicators for determining the effectiveness of steroid therapy for pneumonitis and diagnosing the recurrence of pneumonitis during tapering of the steroid dose. (K.H.)

  7. Effectiveness of measurements of serum KL-6, SP-A, and SP-D in the diagnosis of radiation pneumonitis

    International Nuclear Information System (INIS)

    The authors prospectively assessed the effectiveness of measuring serum concentrations of 3 markers, KL-6, surfactant protein-A (SP-A), and surfactant protein-D (SP-D), in the diagnosis of radiation pneumonitis. The subjects were 127 patients (102 men, 25 women; mean age; 67 years; 123 with lung cancer and 4 with mediastinal tumors). The patients were irradiated with 10-80 Gy (mean dose, 55.3 Gy), and combination chemotherapy was administered to 96 patients. Blood samples were collected weekly during radiotherapy, and every 2 weeks for 4 months after radiotherapy. KL-6, SP-A, and SP-D were measured in the serum samples obtained. None of the markers tended to increase in any of the 35 patients not diagnosed with radiation pneumonitis. Limited radiation pneumonitis occurred in 84 patients, and severe pneumonitis beyond the radiation field developed in 8 patients. In the severe pneumonitis patients, all of the markers clearly tended to increase before and after the crisis of the pneumonitis. In the severe pneumonitis patients, the maximum serum marker values increased to ≥3 fold the level of KL-6, ≥4 fold the level of SP-D, and ≥2 fold the level of SP-A, more than in the limited pneumonitis patients. Until now radiation pneumonitis has been mainly diagnosed by imaging, however, measuring the serum concentrations of the markers KL-6, SP-A, and SP-D, in addition to diagnostic imaging, will enable more accurate and rapid diagnosis of severe pneumonitis than before. These markers also seem to be useful indicators for determining the effectiveness of steroid therapy for pneumonitis and diagnosing the recurrence of pneumonitis during tapering of the steroid dose. (K.H.)

  8. Draft Genome Sequences of the Antimicrobial Producers Pseudomonas sp. TAA207 and Pseudomonas sp. TAD18 Isolated from Antarctic Sediments.

    Science.gov (United States)

    Presta, Luana; Inzucchi, Ilaria; Bosi, Emanuele; Fondi, Marco; Perrin, Elena; Maida, Isabel; Miceli, Elisangela; Tutino, Maria Luisa; Lo Giudice, Angelina; de Pascale, Donatella; Fani, Renato

    2016-01-01

    We report here the draft genome sequence of the Pseudomonas sp. TAA207 and Pseudomonas sp. TAD18 strains, isolated from Antarctic sediments during a summer campaign near coastal areas of Terra Nova Bay (Antarctica). Genome sequence knowledge allowed the identification of genes associated with the production of bioactive compounds and antibiotic resistance. Furthermore, it will be instrumental for comparative genomics and the fulfillment of both basic and application-oriented investigations. PMID:27469957

  9. Draft Genome Sequences of the Antimicrobial Producers Pseudomonas sp. TAA207 and Pseudomonas sp. TAD18 Isolated from Antarctic Sediments

    OpenAIRE

    Presta, Luana; Inzucchi, Ilaria; Bosi, Emanuele; Fondi, Marco; Perrin, Elena; Maida, Isabel; Miceli, Elisangela; Tutino, Maria Luisa; Lo Giudice, Angelina; de Pascale, Donatella; Fani, Renato

    2016-01-01

    We report here the draft genome sequence of the Pseudomonas sp. TAA207 and Pseudomonas sp. TAD18 strains, isolated from Antarctic sediments during a summer campaign near coastal areas of Terra Nova Bay (Antarctica). Genome sequence knowledge allowed the identification of genes associated with the production of bioactive compounds and antibiotic resistance. Furthermore, it will be instrumental for comparative genomics and the fulfillment of both basic and application-oriented investigations.

  10. Enhanced lipid production of three microalgae Dunaliella tertiolecta, Nannochloropsis sp and Scenedesmus sp by manipulating of cultivation condition

    OpenAIRE

    Rukminasari, Nita

    2013-01-01

    Microalgae is one of potential source for biodiesel due to high efficiency of solar energy conversion to chemical energy. Several microalgae also have high lipid content per dry weight biomass. The aims of the present work to study the effects of temperature and nutrient depletion on the growth and lipid content of three selected microalgae (Dunaliella tertiolecta, Nannochloropsis sp and Scenedesmus sp) in view of their possible utilization as raw materials for biodiesel production. In ad...

  11. UJI POTENSI Gliocladium sp TERHADAP PERTUMBUHAN DAN PRODUKSI TANAMAN TOMAT

    Directory of Open Access Journals (Sweden)

    Lina Herlina

    2013-09-01

    Full Text Available AbstrakMikroorganisme tanah seperti Gliocladium sp dapat bertindak sebagai dekomposer dan juga sebagai agen pengendali hayati patogen tanaman hal ini memberikan harapan untuk mengurangi penggunaan pupuk dan fungisida sintetik. Tujuan penelitian untuk menguji potensi biofertililzer Gliocladium sp terhadap pertumbuhan dan produksi buah tomat. Variabel bebas yaitu bioferlizer Gliocladium sp  dengan dosis (g/tanaman 0,50, 100, 150, dan 200 .Variabel tergantung adalah pertumbuhan dan produksi tanaman tomat. Parameter pertumbuhan yang diukur adalah  tinggi tanaman, kandungan klorofil a dan b. Parameter hasil tanaman yang diukur adalah berat buah setelah panen. Hasil uji Anava satu jalan menunjukkan bahwa pemberian Gliocladium sp perpengaruh terhadap tinggi tanaman, kandungan klorofil a dan klorofil b, berat tomat  . Hasil uji lanjut Duncan menunjukkan bahwa dosis 100, g 150 g dan 200 g tidak berbeda signifikan terhadap tinggi tanaman, dosis 150g dan 200 g tidak berbedan nyata dalam pembentukan klorofil a dan klorofil b. Pemberian Gliocladium dosis 150g paling tinggi terhadap berat buah. Simpulan dalam penelitian ini bahwa pemberian Gliokompos sp berpengaruh terhadap pertumbuhan dan produksi buah tomat. AbstractSoil microorganisms such as Gliocladium sp. can play role in the decomposition and can also become the biological control of pathogenic plants. The animal is potentially reduce the use of fertilizers and synthetic fungidid. The aim of the study was to test the potential effect of biofertililzer Gliocladium sp. on the growth and production of tomatoes. The independent variables was biofertilizer Gliocladium sp. at various dosages (g/plant of 0, 50, 100, 150, dan 200. The dependent variables were the growth and the production of tomatoes. The growth parameter measured were plant height, as well as a and b chlorophyl contents.  The crop parameter was the fruit weight post-harvest.  A one-way anova showed that Gliocladium sp. affected the

  12. Using SP and SF to Lower Cement Content

    Directory of Open Access Journals (Sweden)

    Yassen A. Saleh

    2013-05-01

    Full Text Available In the present research, using different percents of superplasticizer (SP and silica fume (SF to improve the characteristics of concrete is performed. SP and SF are added to two types of  normal concrete, the first is of mixing ratio (1:2:4 and the second is of mixing ratio (1:1.5:3.28The results show that adding SF lead to increase compressive strength for first mix by about 45.3% and 47.7% while adding SP lead to increase the compressive strength by about 43% and 41%  compared to reference mix at 7 and 28 day respectively. The corresponding values for second mix are 46.7% , 49%, 44% and 43% respectively.The maximum compressive strength when SP and SF used together can be attained when the percents of SF and SP are 5% and 3% respectively. The increase in compressive strength is about 49.3% and 48.4%  for first mix, while the corresponding values for second mix are 52.4% and 51.2% as they compared to reference mix at 7 and 28 day respectively.For Tensile strength, adding SP lead to increase it by about 29.2% and 31.6% for first and second mix respectively, while the corresponding values when adding SF are 38.1% and 40.3%. The effect of using SP and SF together on increase tensile strength is more than the effect of using each one separately. The maximum tensile strength can be attained when the percents of SF and SP are 5% and 3% respectively as they increase the tensile strength by about 38.9% and 40.7% for first and second mix.The effect of using admixtures on cement content can be noted clearly as the maximum reduction percents are about 8.7% and 9.35% for first and second mix respectively when the percent of SP is 3%. The corresponding values are 9.4% and 11.26% when the percent of SF is 5%. Using SP and SF together at percents 3% and 5% respectively lead to reduce cement content by about 10.15% and 13.54% for first and second mix respectively.

  13. PERBAIKAN PERTUMBUHAN DAN HASIL STEVIA (Stevia rebaudiana BERTONI M) MELALUI APLIKASI Trichoderma sp.

    OpenAIRE

    Haryuni -

    2013-01-01

    AbstrakTujuan penelitian ini adalah menguji perbaikan pertumbuhan dan hasil stevia (Stevia rebaudiana Bertoni M) melalui penggunaan  Trichoderma sp.  Perbanyakan  Trichoderma sp. dilakukan di laboratorium Balai Proteksi Perkebunan di Salatiga Jawa Tengah. Penelitian dirancang menggunakan rancangan factorial dengan dua faktor. Faktor pertama adalah inokulasi Trichoderma sp (To = tanpa  Trichoderma sp. & T1 = menggunakan Trichoderma sp. 100 g.  Faktor kedua adalah variasi aplikasi perlakuan...

  14. Metformin inhibits pancreatic cancer cell and tumor growth and downregulates Sp transcription factors.

    Science.gov (United States)

    Nair, Vijayalekshmi; Pathi, Satya; Jutooru, Indira; Sreevalsan, Sandeep; Basha, Riyaz; Abdelrahim, Maen; Samudio, Ismael; Safe, Stephen

    2013-12-01

    Metformin is a widely used antidiabetic drug, and epidemiology studies for pancreatic and other cancers indicate that metformin exhibits both chemopreventive and chemotherapeutic activities. Several metformin-induced responses and genes are similar to those observed after knockdown of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 by RNA interference, and we hypothesized that the mechanism of action of metformin in pancreatic cancer cells was due, in part, to downregulation of Sp transcription factors. Treatment of Panc1, L3.6pL and Panc28 pancreatic cancer cells with metformin downregulated Sp1, Sp3 and Sp4 proteins and several pro-oncogenic Sp-regulated genes including bcl-2, survivin, cyclin D1, vascular endothelial growth factor and its receptor, and fatty acid synthase. Metformin induced proteasome-dependent degradation of Sps in L3.6pL and Panc28 cells, whereas in Panc1 cells metformin decreased microRNA-27a and induced the Sp repressor, ZBTB10, and disruption of miR-27a:ZBTB10 by metformin was phosphatase dependent. Metformin also inhibited pancreatic tumor growth and downregulated Sp1, Sp3 and Sp4 in tumors in an orthotopic model where L3.6pL cells were injected directly into the pancreas. The results demonstrate for the first time that the anticancer activities of metformin are also due, in part, to downregulation of Sp transcription factors and Sp-regulated genes. PMID:23803693

  15. On the fourth Diadema species (Diadema-sp from Japan.

    Directory of Open Access Journals (Sweden)

    Seinen Chow

    Full Text Available Four long-spined sea urchin species in the genus Diadema are known to occur around the Japanese Archipelago. Three species (D. savignyi, D. setosum, and D. paucispinum are widely distributed in the Indo-Pacific Ocean. The fourth species was detected by DNA analysis among samples originally collected as D. savignyi or D. setosum in Japan and the Marshall Islands and tentatively designated as Diadema-sp, remaining an undescribed species. We analyzed nucleotide sequences of the cytochrome oxidase I (COI gene in the "D. savignyi-like" samples, and found all 17 individuals collected in the mainland of Japan (Sagami Bay and Kyushu to be Diadema-sp, but all nine in the Ryukyu Archipelago (Okinawa and Ishigaki Islands to be D. savignyi, with large nucleotide sequence difference between them (11.0%±1.7 SE. Diadema-sp and D. savignyi shared Y-shaped blue lines of iridophores along the interambulacrals, but individuals of Diadema-sp typically exhibited a conspicuous white streak at the fork of the Y-shaped blue iridophore lines, while this feature was absent in D. savignyi. Also, the central axis of the Y-shaped blue lines of iridophores was approximately twice as long as the V-component in D. savignyi whereas it was of similar length in Diadema-sp. Two parallel lines were observed to constitute the central axis of the Y-shaped blue lines in both species, but these were considerably narrower in Diadema-sp. Despite marked morphological and genetic differences, it appears that Diadema-sp has been mis-identified as D. savignyi for more than half a century.

  16. Identification of microorganisms of Phytophthora genre associated to Quercus sp. and Pinus sp. species in the provinces of Guatemala and Sacatepéquez

    Directory of Open Access Journals (Sweden)

    José Humberto Calderón Díaz

    2015-07-01

    Full Text Available The mean purpose of this research was to identify microorganism belonging to Phytophthora genera which are affecting mixed natural forests and nurseries of Pinus sp. and Quercus sp. These species have economic and social impact in provinces such as Guatemala and Sacatepéquez. Soil and vegetal tissue were used to isolate Phytophthora from natural forest of Guatemala, 45 Pinus sp. and 10 Quercus sp. were sampled and from nurseries 88 Pinus sp. and 11 Quercus sp. From Sacatepéquez province, from natural forest system were sampled 48 Pinus sp. and 15 Quercus sp. From nurseries were sampled 58 Pinus sp. and 25 Quercus sp. After processing the samples from soil and roots 13 were found positive to Phytophthora sp. in Pinus maximinoi, 10 from Guatemala and three from Sacatepéquez provinces. The culture of Phytophthora sp. on PDA produced two colonies without define form and five stoloniferous, five semipetaloid, one stelade type colonies. VP16 isolate was inoculated in five species of pine for pathogenicity test, causing high percentages of incidence and severity on Pinus caribaea, P. oocarpa, P. pseudostrobus and P. maximinoi and low rates of incidence and severity on Pinus tecunumanii.

  17. Efecto de la coinmovilización de la microalga Chlorella sorokiniana con la bacteria promotora de crecimiento vegetal Azospirillum brasilense, en el crecimiento poblacional microalgal y capacidad de remoción de amonio como uso potencial en el tratamiento..

    Directory of Open Access Journals (Sweden)

    Guillot Monroy Gabriel

    2006-06-01

    Full Text Available Se desarrollaron dos experimentos de coinmovilización de la microalga Chlorella sorokiniana con la bacteria promotora
    de crecimiento vegetal (PGPB Azospirillum brasilense en esferas de alginato, para evaluar la influencia de la bacteria en el crecimiento poblacional y en la capacidad de remoción de amonio de la microalga; con el fin de establecer el potencial que pueda tener la coinmovilización de estos microorganismos en el tratamiento terciario de aguas residuales. Los resultados revelan un significativo incremento de la población cuando C.
    sorokiniana es coinmovilizada con A. brasilense, aunque no se observó un efecto significativo en la remoción de amonio. Los resultados obtenidos en el presente trabajo, reflejan la importancia de avanzar en el estudio de un sistema coinmovilizado altamente eficiente para ser utilizado en tratamiento de aguas residuales. La coinmovilización
    de C. sorokiniana con A. brasilense, muestra la habilidad de esta bacteria para influir de manera positiva en el crecimiento y fisiología de la microalga y por lo tanto la remoción de amonio puede ser incrementada.

  18. 巴西固氮螺菌中杂合双组分蛋白Org35与NifA的相互作用%The Interaction between NifA and Hybrid Two Component Protein Org35 of Azospirillum brasilense

    Institute of Scientific and Technical Information of China (English)

    崔艳华; 伍丽娴; 洪媛媛; 陈三凤

    2010-01-01

    巴西固氮螺菌(Azospirillum brasilense)可以与玉米(Zea mays)、小麦(Triticum aestivum)等重要作物联合固氮,是重要的潜在生物肥料.NifA蛋白是所有固氮基因转录所必需的激活蛋白.本研究利用融合蛋白下拉分析,探讨了Org35蛋白与NifA蛋白的相互作用.研究表明二者存在互作.Org35蛋白由3个独立结构区域组成,即PAS结构域、组氨酸蛋白激酶结构域和应答调节蛋白区域.本研究采用融合蛋白下拉分析了Org35蛋白三个结构域与NifA的互作关系,结果表明Org35蛋白与NifA蛋白之间的相互作用是由PAS结构域介导的.

  19. 固氮螺菌 (Azosprillum brasilense)NO40在红壤性水稻土上的接种效应%Effects of inoculation with tropical rice associative N2-fixing bacteria Azospirillum brasilense NO40 in the red paddy soil

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Effects of inoculation with Azospirillum brasilense NO40 isolatedfrom Egypt on rice growth and yields under different nitrogen fertilizer levels were investigated at Dongyang county of Zhejiang province. The results showed that the counts of colony grown on nitrogen-free medium isolated from rice rhizosphere and root were increased by inoculating with NO40 in contrast to the control, irrespective of the nitrogen fertilizer levels and rice growing periods. It was found that the plant height, chlorophyll content of the newly developed rice leaves were significantly increased after inoculating with NO40.%裂区设计田间试验结果表明,在3个供氮水平下接种巴西固氮螺菌(Azospirillumbrasilense)NO40,使分蘖期与灌浆期水稻根际及根内的固氮菌数量均比对照明显增加,而土体中的固氮菌数量未见明显变化;同时,接种该菌株可显著提高分蘖期与灌浆期水稻新展开叶的叶绿素含量及水稻株高,在低氮水平下使水稻单株干物重和单株籽粒产量有所提高。

  20. Enantiospecific sp2-sp3 coupling of secondary and tertiary boronic esters

    Science.gov (United States)

    Bonet, Amadeu; Odachowski, Marcin; Leonori, Daniele; Essafi, Stephanie; Aggarwal, Varinder K.

    2014-07-01

    The cross-coupling of boronic acids and related derivatives with sp2 electrophiles (the Suzuki-Miyaura reaction) is one of the most powerful C-C bond formation reactions in synthesis, with applications that span pharmaceuticals, agrochemicals and high-tech materials. Despite the breadth of its utility, the scope of this Nobel prize-winning reaction is rather limited when applied to aliphatic boronic esters. Primary organoboron reagents work well, but secondary and tertiary boronic esters do not (apart from a few specific and isolated examples). Through an alternative strategy, which does not involve using transition metals, we have discovered that enantioenriched secondary and tertiary boronic esters can be coupled to electron-rich aromatics with essentially complete enantiospecificity. As the enantioenriched boronic esters are easily accessible, this reaction should find considerable application, particularly in the pharmaceutical industry where there is growing awareness of the importance of, and greater clinical success in, creating biomolecules with three-dimensional architectures.