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Sample records for azospirillum sp b510

  1. Azospirillum sp. strain B510 enhances rice growth and yield.

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    Isawa, Tsuyoshi; Yasuda, Michiko; Awazaki, Hirotoshi; Minamisawa, Kiwamu; Shinozaki, Satoshi; Nakashita, Hideo

    2010-01-01

    Inoculation experiments with the endophytic bacterium Azospirillum sp. strain B510, an isolate from surface-sterilized stems of field-grown rice, were conducted in pots in a greenhouse, and in paddy fields in Hokkaido, Japan. B510 significantly enhanced the growth of newly generated leaves and shoot biomass under greenhouse conditions. When rice seedlings were treated with 1×10(8) CFU ml(-1), then transplanted to paddy fields, tiller numbers and seed yield significantly increased. Azospirillum sp. strain B510 is a promising bacterial inoculant for plant growth promotion and agricultural practices.

  2. Effects of colonization of a bacterial endophyte, Azospirillum sp. B510, on disease resistance in tomato.

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    Fujita, Moeka; Kusajima, Miyuki; Okumura, Yasuko; Nakajima, Masami; Minamisawa, Kiwamu; Nakashita, Hideo

    2017-08-01

    A plant growth-promoting bacteria, Azospirillum sp. B510, isolated from rice, can enhance growth and yield and induce disease resistance against various types of diseases in rice. Because little is known about the interaction between other plant species and this strain, we have investigated the effect of its colonization on disease resistance in tomato plants. Treatment with this strain by soil-drenching method established endophytic colonization in root tissues in tomato plant. The endophytic colonization with this strain-induced disease resistance in tomato plant against bacterial leaf spot caused by Pseudomonas syringae pv. tomato and gray mold caused by Botrytis cinerea. In Azospirillum-treated plants, neither the accumulation of SA nor the expression of defense-related genes was observed. These indicate that endophytic colonization with Azospirillum sp. B510 is able to activate the innate immune system also in tomato, which does not seem to be systemic acquired resistance.

  3. Impact of Azospirillum sp. B510 inoculation on rice-associated bacterial communities in a paddy field.

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    Bao, Zhihua; Sasaki, Kazuhiro; Okubo, Takashi; Ikeda, Seishi; Anda, Mizue; Hanzawa, Eiko; Kakizaki, Kaori; Sato, Tadashi; Mitsui, Hisayuki; Minamisawa, Kiwamu

    2013-01-01

    Rice seedlings were inoculated with Azospirillum sp. B510 and transplanted into a paddy field. Growth in terms of tiller numbers and shoot length was significantly increased by inoculation. Principal-coordinates analysis of rice bacterial communities using the 16S rRNA gene showed no overall change from B510 inoculation. However, the abundance of Veillonellaceae and Aurantimonas significantly increased in the base and shoots, respectively, of B510-inoculated plants. The abundance of Azospirillum did not differ between B510-inoculated and uninoculated plants (0.02-0.50%). These results indicate that the application of Azospirillum sp. B510 not only enhanced rice growth, but also affected minor rice-associated bacteria.

  4. Complete Genomic Structure of the Cultivated Rice Endophyte Azospirillum sp. B510

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    Kaneko, Takakazu; Minamisawa, Kiwamu; Isawa, Tsuyoshi; Nakatsukasa, Hiroki; Mitsui, Hisayuki; Kawaharada, Yasuyuki; Nakamura, Yasukazu; Watanabe, Akiko; Kawashima, Kumiko; Ono, Akiko; Shimizu, Yoshimi; Takahashi, Chika; Minami, Chiharu; Fujishiro, Tsunakazu; Kohara, Mitsuyo; Katoh, Midori; Nakazaki, Naomi; Nakayama, Shinobu; Yamada, Manabu; Tabata, Satoshi; Sato, Shusei

    2010-01-01

    We determined the nucleotide sequence of the entire genome of a diazotrophic endophyte, Azospirillum sp. B510. Strain B510 is an endophytic bacterium isolated from stems of rice plants (Oryza sativa cv. Nipponbare). The genome of B510 consisted of a single chromosome (3 311 395 bp) and six plasmids, designated as pAB510a (1 455 109 bp), pAB510b (723 779 bp), pAB510c (681 723 bp), pAB510d (628 837 bp), pAB510e (537 299 bp), and pAB510f (261 596 bp). The chromosome bears 2893 potential protein-encoding genes, two sets of rRNA gene clusters (rrns), and 45 tRNA genes representing 37 tRNA species. The genomes of the six plasmids contained a total of 3416 protein-encoding genes, seven sets of rrns, and 34 tRNAs representing 19 tRNA species. Eight genes for plasmid-specific tRNA species are located on either pAB510a or pAB510d. Two out of eight genomic islands are inserted in the plasmids, pAB510b and pAB510e, and one of the islands is inserted into trnfM-CAU in the rrn located on pAB510e. Genes other than the nif gene cluster that are involved in N2 fixation and are homologues of Bradyrhizobium japonicum USDA110 include fixABCX, fixNOQP, fixHIS, fixG, and fixLJK. Three putative plant hormone-related genes encoding tryptophan 2-monooxytenase (iaaM) and indole-3-acetaldehyde hydrolase (iaaH), which are involved in IAA biosynthesis, and ACC deaminase (acdS), which reduces ethylene levels, were identified. Multiple gene-clusters for tripartite ATP-independent periplasmic-transport systems and a diverse set of malic enzymes were identified, suggesting that B510 utilizes C4-dicarboxylate during its symbiotic relationship with the host plant. PMID:20047946

  5. Complete genomic structure of the cultivated rice endophyte Azospirillum sp. B510.

    Science.gov (United States)

    Kaneko, Takakazu; Minamisawa, Kiwamu; Isawa, Tsuyoshi; Nakatsukasa, Hiroki; Mitsui, Hisayuki; Kawaharada, Yasuyuki; Nakamura, Yasukazu; Watanabe, Akiko; Kawashima, Kumiko; Ono, Akiko; Shimizu, Yoshimi; Takahashi, Chika; Minami, Chiharu; Fujishiro, Tsunakazu; Kohara, Mitsuyo; Katoh, Midori; Nakazaki, Naomi; Nakayama, Shinobu; Yamada, Manabu; Tabata, Satoshi; Sato, Shusei

    2010-02-01

    We determined the nucleotide sequence of the entire genome of a diazotrophic endophyte, Azospirillum sp. B510. Strain B510 is an endophytic bacterium isolated from stems of rice plants (Oryza sativa cv. Nipponbare). The genome of B510 consisted of a single chromosome (3,311,395 bp) and six plasmids, designated as pAB510a (1,455,109 bp), pAB510b (723,779 bp), pAB510c (681,723 bp), pAB510d (628,837 bp), pAB510e (537,299 bp), and pAB510f (261,596 bp). The chromosome bears 2893 potential protein-encoding genes, two sets of rRNA gene clusters (rrns), and 45 tRNA genes representing 37 tRNA species. The genomes of the six plasmids contained a total of 3416 protein-encoding genes, seven sets of rrns, and 34 tRNAs representing 19 tRNA species. Eight genes for plasmid-specific tRNA species are located on either pAB510a or pAB510d. Two out of eight genomic islands are inserted in the plasmids, pAB510b and pAB510e, and one of the islands is inserted into trnfM-CAU in the rrn located on pAB510e. Genes other than the nif gene cluster that are involved in N(2) fixation and are homologues of Bradyrhizobium japonicum USDA110 include fixABCX, fixNOQP, fixHIS, fixG, and fixLJK. Three putative plant hormone-related genes encoding tryptophan 2-monooxytenase (iaaM) and indole-3-acetaldehyde hydrolase (iaaH), which are involved in IAA biosynthesis, and ACC deaminase (acdS), which reduces ethylene levels, were identified. Multiple gene-clusters for tripartite ATP-independent periplasmic-transport systems and a diverse set of malic enzymes were identified, suggesting that B510 utilizes C(4)-dicarboxylate during its symbiotic relationship with the host plant.

  6. Azospirillum rugosum sp. nov., isolated from oil-contaminated soil.

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    Young, C C; Hupfer, H; Siering, C; Ho, M-J; Arun, A B; Lai, W-A; Rekha, P D; Shen, F-T; Hung, M-H; Chen, W-M; Yassin, A F

    2008-04-01

    The taxonomic status of a light-orange-coloured bacterial isolate from an oil-contaminated soil sample was characterized by using a polyphasic taxonomic approach. Comparative analysis of 16S rRNA gene sequences demonstrated that the isolate belonged phylogenetically to the genus Azospirillum, with Azospirillum canadense, Azospirillum brasilense and Azospirillum doebereinerae as its closest phylogenetic relatives (97.3, 97.0 and 97.0 % similarity, respectively). DNA-DNA pairing studies showed that the unidentified organism displayed 25.0, 17.0 and 19.0 % relatedness to the type strains of A. brasilense, A. canadense and A. doebereinerae, respectively. The generic assignment was confirmed by chemotaxonomic data, which revealed a fatty acid profile that was characteristic of the genus Azospirillum, consisting of straight-chain saturated and unsaturated fatty acids with C18 : 1 omega 7c as the major fatty acid, and ubiquinone with ten isoprene units (Q-10) as the predominant respiratory quinone. On the basis of both the phenotypic and molecular genetic evidence, it is proposed that the unknown isolate be classified as a representative of a novel species of the genus Azospirillum, for which the name Azospirillum rugosum sp. nov. is proposed. The type strain is IMMIB AFH-6T (=CCUG 53966T=DSM 19657T).

  7. Azospirillum picis sp. nov., isolated from discarded tar.

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    Lin, S-Y; Young, C C; Hupfer, H; Siering, C; Arun, A B; Chen, W-M; Lai, W-A; Shen, F-T; Rekha, P D; Yassin, A F

    2009-04-01

    A polyphasic taxonomic study was performed on a pink-coloured unknown bacterium isolated from discarded road tar. Comparative analysis of the 16S rRNA gene sequence demonstrated that the isolate belongs phylogenetically to the genus Azospirillum with Azospirillum lipoferum, A. melinis and A. rugosum as its closest phylogenetic relatives (96.7, 96.6 and 96.6 % similarity to the respective type strains). The generic assignment was confirmed on the basis of chemotaxonomic data, which revealed a fatty acid profile characteristic for the genus Azospirillum, consisting of straight-chain saturated and unsaturated fatty acids, with C(18 : 1)omega7c as the major unsaturated non-hydroxylated fatty acid, and C(16 : 0) 3-OH as the major hydroxylated fatty acid, and a ubiquinone with ten isoprene units (Q-10) as the predominant respiratory quinone. On the basis of both the phenotypic and molecular genetic evidence, it is proposed that the unknown isolate should be classified within a novel species of the genus Azospirillum, for which the name Azospirillum picis sp. nov. is proposed. The type strain is IMMIB TAR-3(T) (=CCUG 55431(T) =DSM 19922(T)).

  8. Azospirillum formosense sp. nov., a diazotroph from agricultural soil.

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    Lin, Shih-Yao; Shen, Fo-Ting; Young, Li-Sen; Zhu, Zhi-Long; Chen, Wen-Ming; Young, Chiu-Chung

    2012-05-01

    A gram-negative, spiral or rod-shaped, non-spore-forming diazotrophic bacterium, designated CC-Nfb-7(T), was isolated from agricultural soil in Yunlin County, Taiwan. 16S rRNA gene sequence analysis showed that strain CC-Nfb-7(T) was most closely related to Azospirillum brasilense DSM 1690(T) (97.4 % 16S rRNA gene sequence similarity), Azospirillum rugosum IMMIB AFH-6(T) (96.8 %) and Azospirillum oryzae JCM 21588(T) (96.6 %); Azospirillum. DNA-DNA relatedness between strain CC-Nfb-7(T) and A. brasilense DSM 1690(T), A. rugosum DSM 19657(T) and A. oryzae JCM 21588(T) was 38.9, 30.1 and 31.8 %, respectively. The respiratory quinone was ubiquinone Q-10. The major fatty acids were summed feature 8 (consisting of C(18 : 1)ω7c and/or C(18 : 1)ω6c), summed feature 3 (consisting of C(16 : 1)ω7c and/or C(16 : 1)ω6c), summed feature 2 (consisting of C(14 : 0) 3-OH and/or iso-C(16 : 1) I), C(16 : 0), C(18 : 0) 2-OH and C(16 : 0) 3-OH. The polar lipids consisted mainly of phosphatidylglycerol, phosphatidylcholine and one unidentified phospholipid. Furthermore, moderate amounts of phosphatidylethanolamine, phosphatidyldimethylethanolamine and one unidentified aminophospholipid were also detected. Strain CC-Nfb-7(T) could be distinguished from members of phylogenetically related species by differences in phenotypic properties. On the basis of morphological, chemotaxonomic and phylogenetic data, strain CC-Nfb-7(T) represents a novel species within the genus Azospirillum, for which we propose the name Azospirillum formosense sp. nov. The type strain is CC-Nfb-7(T) ( = BCRC 80273(T) = JCM 17639(T) = DSM 24137(T)).

  9. Plant secondary metabolite profiling evidences strain-dependent effect in the Azospirillum-Oryza sativa association.

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    Chamam, Amel; Sanguin, Hervé; Bellvert, Floriant; Meiffren, Guillaume; Comte, Gilles; Wisniewski-Dyé, Florence; Bertrand, Cédric; Prigent-Combaret, Claire

    2013-03-01

    Azospirillum is a plant growth-promoting rhizobacterium (PGPR) able to enhance growth and yield of cereals such as rice, maize and wheat. The growth-promoting ability of some Azospirillum strains appears to be highly specific to certain plant species and cultivars. In order to ascertain the specificity of the associative symbiosis between rice and Azospirillum, the physiological response of two rice cultivars, Nipponbare and Cigalon, inoculated with two rice-associated Azospirillum was analyzed at two levels: plant growth response and plant secondary metabolic response. Each strain of Azospirillum (Azospirillum lipoferum 4B isolated from Cigalon and Azospirillum sp. B510 isolated from Nipponbare) preferentially increased growth of the cultivar from which it was isolated. This specific effect is not related to a defect in colonization of host cultivar as each strain colonizes effectively both rice cultivars, either at the rhizoplane (for 4B and B510) and inside the roots (for B510). The metabolic profiling approach showed that, in response to PGPR inoculation, profiles of rice secondary metabolites were modified, with phenolic compounds such as flavonoids and hydroxycinnamic derivatives being the main metabolites affected. Moreover, plant metabolic changes differed according to Azospirillum strain×cultivar combinations; indeed, 4B induced major secondary metabolic profile modifications only on Cigalon roots, while B510, probably due to its endophytic feature, induced metabolic variations on shoots and roots of both cultivars, triggering a systemic response. Plant secondary metabolite profiling thereby evidences the specific interaction between an Azospirillum strain and its original host cultivar. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

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    Fondi, Marco

    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. PMID:25610702

  11. 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.

  12. FTIR spectroscopic study of biofilms formed by the rhizobacterium Azospirillum brasilense Sp245 and its mutant Azospirillum brasilense Sp245.1610

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    Tugarova, Anna V.; Scheludko, Andrei V.; Dyatlova, Yulia A.; Filip'echeva, Yulia A.; Kamnev, Alexander A.

    2017-07-01

    Biofilms are spatially and metabolically structured communities of microorganisms, representing a mode of their existence which is ubiquitous in nature, with cells localised within an extracellular biopolymeric matrix, attached to each other, at an interface. For plant-growth-promoting rhizobacteria (PGPR), the formation of biofilms is of special importance due to their primary localisation at the surface of plant root systems. In this work, FTIR spectroscopy was used, for the first time for bacteria of the genus Azospirillum, to comparatively study 6-day-mature biofilms formed on the surface of ZnSe discs by the rhizobacterium Azospirillum brasilense Sp245 and its mutant A. brasilense Sp245.1610. The mutant strain, having an Omegon Km insertion in the gene of lipid metabolism fabG1 on the plasmid AZOBR_p1, as compared to the wild-type strain Sp245 (see http://dx.doi.org/10.1134/S1022795413110112)

  13. 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)).

  14. Azospirillum thiophilum sp. nov., a diazotrophic bacterium isolated from a sulfide spring.

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    Lavrinenko, Ksenia; Chernousova, Elena; Gridneva, Elena; Dubinina, Galina; Akimov, Vladimir; Kuever, Jan; Lysenko, Anatoly; Grabovich, Margarita

    2010-12-01

    A novel nitrogen-fixing strain, designated BV-S(T), was isolated from a sulfur bacterial mat collected from a sulfide spring of the Stavropol Krai, North Caucasus, Russia. Strain BV-S(T) grew optimally at pH 7.5 and 37°C. According to the results of phylogenetic analysis, strain BV-S(T) belonged to the genus Azospirillum within the family Rhodospirillaceae of the class Alphaproteobacteria. Within the genus Azospirillum, strain BV-S(T) was most closely related to Azospirillum doebereinerae GSF71(T), A. picis IMMIB TAR-3(T) and A. lipoferum ATCC 29707(T) (97.7, 97.7 and 97.4 % 16S rRNA gene sequence similarity, respectively). DNA-DNA relatedness between strain BV-S(T) and A. doebereinerae DSM 13131(T), A. picis DSM 19922(T) and A. lipoferum ATCC 29707(T) was 38, 55 and 42 %, respectively. Similarities between nifH sequences of strain BV-S(T) and members of the genus Azospirillum ranged from 94.5 to 96.8 %. Chemotaxonomic characteristics (quinone Q-10, major fatty acid C(18 : 1)ω7c and G+C content 67 mol%) were similar to those of members of the genus Azospirillum. In contrast to known Azospirillum species, strain BV-S(T) was capable of mixotrophic growth under microaerobic conditions with simultaneous utilization of organic substrates and thiosulfate as electron donors for energy conservation. Oxidation of sulfide was accompanied by deposits of sulfur globules within the cells. Based on these observations, strain BV-S(T) is considered as a representative of a novel species of the genus Azospirillum, for which the name Azospirillum thiophilum sp. nov. is proposed. The type strain is BV-S(T) (=DSM 21654(T) =VKM B-2513(T)).

  15. 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)).

  16. Azospirillum melinis sp. nov., a group of diazotrophs isolated from tropical molasses grass.

    Science.gov (United States)

    Peng, Guixiang; Wang, Huarong; Zhang, Guoxia; Hou, Wei; Liu, Yang; Wang, En Tao; Tan, Zhiyuan

    2006-06-01

    Fifteen bacterial strains isolated from molasses grass (Melinis minutiflora Beauv.) were identified as nitrogen-fixers by using the acetylene-reduction assay and PCR amplification of nifH gene fragments. These strains were classified as a unique group by insertion sequence-PCR fingerprinting, SDS-PAGE protein patterns, DNA-DNA hybridization, 16S rRNA gene sequencing and morphological characterization. Phylogenetic analysis of the 16S rRNA gene indicated that these diazotrophic strains belonged to the genus Azospirillum and were closely related to Azospirillum lipoferum (with 97.5 % similarity). In all the analyses, including in addition phenotypic characterization using Biolog MicroPlates and comparison of cellular fatty acids, this novel group was found to be different from the most closely related species, Azospirillum lipoferum. Based on these data, a novel species, Azospirillum melinis sp. nov., is proposed for these endophytic diazotrophs of M. minutiflora, with TMCY 0552(T) (=CCBAU 5106001(T) = LMG 23364(T) = CGMCC 1.5340(T)) as the type strain.

  17. Azospirillum palatum sp. nov., isolated from forest soil in Zhejiang province, China.

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    Zhou, Yu; Wei, Wei; Wang, Xu; Xu, Lihong; Lai, Ren

    2009-02-01

    A Gram-negative bacterium designated ww 10(T) was isolated by plating dilutions from forest soil in Zhejiang province, China. Strain ww 10(T) was investigated by polyphasic taxonomic study including phenotypic and phylogenetic analysis. Cells of ww 10(T) were Gram-negative, strictly aerobic, motile with peritrichous flagella and rod-shaped. The strain grew optimally at 30-37 masculineC and pH 6.0-8.0. The major fatty acids were C(18:1)omega7C, cyclo-C(19:0) omega8C and C(16:0). The respiratory quinones contained a large amount of Q-10, a moderate component of Q-9 and a minor of Q-8. The G+C content of genomic DNA was about 67.3 mol%. Phylogenetic analysis revealed that strain ww 10(T) belongs to the phyletic cluster of genus Azospirillum and displayed 16S rRNA gene sequence similarity lower than 96.3% to the four closest described species of the genera Azospirillum and Roseomonas. Results of polyphasic taxonomic analysis showed that strain ww 10(T) represents a novel species in the genus Azospirillum, for which the name Azospirillum palatum sp. nov., is proposed. The type strain is ww 10(T) (=LMG 24444(T)=KCTC 13200(T)=CCTCC AB 207189(T)).

  18. Azospirillum zeae sp. nov., a diazotrophic bacterium isolated from rhizosphere soil of Zea mays.

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    Mehnaz, Samina; Weselowski, Brian; Lazarovits, George

    2007-12-01

    Two free-living nitrogen-fixing bacterial strains, N6 and N7(T), were isolated from corn rhizosphere. A polyphasic taxonomic approach, including morphological characterization, Biolog analysis, DNA-DNA hybridization, and 16S rRNA, cpn60 and nifH gene sequence analysis, was taken to analyse the two strains. 16S rRNA gene sequence analysis indicated that strains N6 and N7(T) both belonged to the genus Azospirillum and were closely related to Azospirillum oryzae (98.7 and 98.8 % similarity, respectively) and Azospirillum lipoferum (97.5 and 97.6 % similarity, respectively). DNA-DNA hybridization of strains N6 and N7(T) showed reassociation values of 48 and 37 %, respectively, with A. oryzae and 43 % with A. lipoferum. Sequences of the nifH and cpn60 genes of both strains showed 99 and approximately 95 % similarity, respectively, with those of A. oryzae. Chemotaxonomic characteristics (Q-10 as quinone system, 18 : 1omega7c as major fatty acid) and G+C content of the DNA (67.6 mol%) were also similar to those of members of the genus Azospirillum. Gene sequences and Biolog and fatty acid analysis showed that strains N6 and N7(T) differed from the closely related species A. lipoferum and A. oryzae. On the basis of these results, it is proposed that these nitrogen-fixing strains represent a novel species. The name Azospirillum zeae sp. nov. is suggested, with N7(T) (=NCCB 100147(T)=LMG 23989(T)) as the type strain.

  19. [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.

  20. Azospirillum agricola sp. nov., a nitrogen-fixing species isolated from cultivated soil.

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    Lin, Shih-Yao; Liu, You-Cheng; Hameed, Asif; Hsu, Yi-Han; Huang, Hsin-I; Lai, Wei-An; Young, Chiu-Chung

    2016-03-01

    A polyphasic approach was used to characterize a novel nitrogen-fixing bacterial strain, designated CC-HIH038T, isolated from cultivated soil in Taiwan. Cells of strain CC-HIH038T were Gram-stain-negative, facultatively aerobic and spiral-shaped, with motility provided by a single polar flagellum. The 16S rRNA gene sequence analysis of strain CC-HIH038T showed highest sequence similarity to Azospirillum doebereinerae (98.0 %), Azospirillum thiophilum (97.5 %), Azospirillum rugosum (97.4 %) and Azospirillum zeae (97.2 %) and lower sequence similarity ( Azospirillum. According to DNA-DNA association, the relatedness values of strain CC-HIH038T with A. doebereinerae, A. thiophilum, A. rugosum and A. zeae were 51.8 %, 41.2 %, 56.5 % and 37.5 %, respectively. Strain CC-HIH038T was able to grow at 20-37 °C and pH 7.0-8.0. Strain CC-HIH038T gave positive amplification for dinitrogen reductase (nifH gene); the activity was recorded as 8.4 nmol ethylene h- 1. The predominant quinone system was ubiquinone Q-10 and the DNA G+C content was 68.8 mol%. The major fatty acids found in strain CC-HIH038T were C16 : 0, iso-C18 : 0, C16 : 0 3-OH, C14 : 0 3-OH/iso-C16 : 1 and C18 : 1ω7c/C18 : 1ω6c. Based on the distinct phylogenetic, phenotypic and chemotaxonomic traits together with results of comparative 16S rRNA gene sequence analysis, strain CC-HIH038T is considered to represent a novel species in the genus Azospirillum, for which the name Azospirillum agricola sp. nov. is proposed. The type strain is CC-HIH038T ( = BCRC 80909T = JCM 30827T).

  1. Azospirillum humicireducens sp. nov., a nitrogen-fixing bacterium isolated from a microbial fuel cell.

    Science.gov (United States)

    Zhou, Shungui; Han, Luchao; Wang, Yueqiang; Yang, Guiqin; Zhuang, Li; Hu, Pei

    2013-07-01

    A Gram-negative, facultative anaerobic, motile, spiral, straight-to-slightly curved rod-shaped and nitrogen-fixing strain, designated SgZ-5(T), was isolated from a microbial fuel cell (MFC) and was characterized by means of a polyphasic approach. Growth occurred with 0-1 % (w/v) NaCl (optimum 1 %) and at pH 5.5-8.5 (optimum pH 7.2) and at 25-37 °C (optimum 30 °C) in nutrient broth (NB). The strain had the ability to grow under anaerobic conditions via the oxidation of various organic compounds coupled to the reduction of anthraquione-2,6-disulfonate (AQDS). Chemotaxonomic characteristics (main ubiquinone Q-10, major fatty acid C18 : 1ω7c/C18 : 1ω6c and DNA G+C content 67.7 mol%) were similar to those of members of the genus Azospirillum. According to the results of phylogenetic analyses, strain SgZ-5(T) belonged to the genus Azospirillum within the family Rhodospirillaceae of the class Alphaproteobacteria, and was related most closely to the type strains of Azospirillum lipoferum, Azospirillum thiophilum and Azospirillum oryzae (98.0, 97.6 and 97.1 % 16S rRNA gene sequence similarity, respectively). DNA-DNA pairing studies showed that the unidentified organism displayed reassociation values of 36.7 ± 3.7, 24.1 ± 2.2 and 22.3 ± 2.4 % to the type strains of A. lipoferum, A. thiophilum and A. oryzae, respectively. Similarities between nifH gene sequences of strain SgZ-5(T) and members of the genus Azospirillum ranged from 94.0 to 97.0 %. A combination of phenotypic, chemotaxonomic, phylogenetic and genotypic data clearly indicated that strain SgZ-5(T) represents a novel species, for which the name Azospirillum humicireducens sp. nov. is proposed. The type strain is SgZ-5(T) ( = CCTCC AB 2012021(T) = KACC 16605(T)).

  2. Azospirillum IV

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  4. Rhizobacteria Pseudomonas fluorescens and Azospirillum sp. association enhances growth of Lactuca sativa L. under tropical conditions

    Directory of Open Access Journals (Sweden)

    Amael APONTE

    2017-06-01

    Full Text Available The selection of microorganisms that enhance plant growth and confer biotic and abiotic tolerance to crops constitutes a biotechnology currently gaining importance on a global scale. The aim of this investigation was to evaluate the effects of inoculating rhizobacteria to lettuce (Lactuca sativa L. on seed germination and vegetative development in order to use isolates as potential biofertilizers under tropical conditions. Five isolates of Pseudomonas fluorescens (Pf and one of Azospirillum sp. (Az were inoculated to seeds using a bacterial suspension of 1.5*108 CFU*mL-1. In vitro, none of the isolates promoted germination. In vivo, isolates promoted growth and acted as stress alleviators by conferring tolerance to high temperatures (≥ 30 °C. The highest seedling emergence percentages were induced by the association of P.fluorescens with Azospirillum. This association also promoted the highest leaf-area in 25 d seedlings and exhibited a significantly higher dry-weight in 40 d plants compared to the control (P≤0.05 supporting the advantages of bio-consortiums over individual strains. The strains were able to produce dependent L-tryptophan indole-3-acetic acid (IAA, to solubilize phosphorous in vitro and tolerated at least 5%-salt stress. The results indicate that isolate Pf (26 and Az possess plant growth promoting rhizobacteria (PGPR traits and should be further assessed. This study suggests that P. fluorescens and Azospirillum act synergically and are able to trigger an induced-tolerance mechanism in lettuce under abiotic stress.

  5. Promoting the Growth of Chlorella vulgaris in Secondary Wastewater Treatment Effluent of Tofu Industry using Azospirillum sp

    OpenAIRE

    Wahyunanto Agung Nugroho; Musthofa Lutfi; Bambang Susilo

    2016-01-01

    The objective of this research is to investigate the influence of growth promoting bacteria (GPB) Azospirillum sp on the growth of microalgae Chlorella vulgaris in wastewater of tofu industry as a medium. To observe the influence, about 106 cells/mL of Chlorella vulgaris was cultivated in 1 L of wastewater of tofu industry. The wastewater was an effluent of an aerobic treatment. Six different treatments were set regarding to the Azospirillum sp added to the medium. The glass was marked as A0 ...

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Azospirillum soli sp. nov., a nitrogen-fixing species isolated from agricultural soil.

    Science.gov (United States)

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

    2015-12-01

    An aerobic, Gram-stain-negative, rod or spiral-shaped diazotrophic bacterium (designated strain CC-LY788T), was isolated from agricultural soil in Taiwan. Strain CC-LY788T was able to grow at 25-40 °C, pH 6.0-8.0 and tolerated NaCl to 2.0% (w/v). Positive for nitrogen fixation with the activity recorded as 6.5 nmol ethylene h(-1). Strain CC-LY788T showed highest 16S rRNA gene sequence similarity to Azospirillum picis DSM 19922T (97.2%) and Azospirillum rugosum DSM 19657T (97.1%) and lower sequence similarities (Azospirillum. According to the DNA-DNA hybridization, the relatedness values of strain CC-LY788T with A. picis DSM 19922T and A. rugosum DSM 19657T were 51.1±5.5% and 46.8±2.1%, respectively. Strain CC-LY788T was positive for the rapid identification of the genus-specific primer set. The respiratory quinone system was ubiquinone (Q-10) and the DNAG+C content was 69.8 mol%. The major fatty acids found in strain CC-LY788T were C16 : 0, C18 : 1 2-OH, C14 : 0 3-OH/C16 : 1 iso I (summed feature 2), C16 : 1ω7c/C16 : 1ω6c (summed feature 3), C18 : 0 ante/C18 : 2ω6,9c (summed feature 5) and C18 : 1ω7c/C18 : 1ω6c (summed feature 8). Based on the phylogenetic, phenotypic and chemotaxonomic features, strain CC-LY788T represents a novel species of the genus Azospirillum, for which the name Azospirillum soli sp. nov. is proposed. The type strain is CC-LY788T (=BCRC 80569T=JCM 18820T).

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

    Directory of Open Access Journals (Sweden)

    Santi Nur Handayani

    2011-11-01

    Full Text Available 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 dari isolat lokal Laboratorium Mikrobiologi, Fakultas Biologi Universitas Jenderal Soedirman. Tujuan penelitian adalah untuk mendapatkan ekstrak kasar lipase dan menentukan karakteristik sifat-sifat biokimiawinya. Metode yang digunakan antara lain peremajaan bakteri Azospirillum sp.PRD1, dan produksi inokulum, penentuan waktu produksi optimum dan fase pertumbuhan bakteri, ekstraksi dan produksi ekstrak kasar lipase dan penentuan karakteristik sifat-sifat biokimiawinya. Hasil penelitian diperoleh ekstrak kasar lipase dari inokulum berumur 7 jam dan medium produksi dengan induser minyak zaitun yang diinkubasi selama 3 jam memiliki aktivitas spesifik 7,0547 Unit/mg. Lipase ekstrak kasar optimum pada pH 7, suhu 40 oC dan waktu inkubasi selama 25 menit. Lipase merupakan metaloenzim dengan kofaktor Zn2+ , Mn2+, Hg2+, Ca2+, Co2+ and Mg2+.

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

    Science.gov (United States)

    Drogue, Benoît; Sanguin, Hervé; Chamam, Amel; Mozar, Michael; Llauro, Christel; Panaud, Olivier; Prigent-Combaret, Claire; Picault, Nathalie; Wisniewski-Dyé, Florence

    2014-01-01

    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 defense 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 analyzes of Oryza sativa japonica cultivars Cigalon and Nipponbare were performed, by using microarrays, seven days post-inoculation with Azospirillum lipoferum 4B (isolated from Cigalon) or Azospirillum sp. B510 (isolated from Nipponbare) and compared to the respective non-inoculated condition. A total of 7384 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 defense, 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 signaling highlight the complexity of hormone signaling networks in the Azospirillum

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. [Effect of flavonoids on the composition of surface glycopolymers in Azospirillum lipoferum Sp59b].

    Science.gov (United States)

    Kanevskiĭ, M V; Konnova, S A; Boĭko, A S; Fedonenko, Iu P; Sigida, E N; Ignatov, V V

    2014-01-01

    Cultivation of the type strain Azospirillum lipoferum Sp59b in the presence of the flavonoid quercetin induced modification of the structure of the bacterial lipopolysaccharide. Cultivation in the presence of the flavonoid was shown to result in altered serological characteristics of the bacteria, increased heterogeneity of the outer membrane lipopolysaccharide pool, as well as in modified composition and fatty acid ratio of lipid A. The flavonoid was shown to induce the synthesis of the O-specific polysaccharide with the repeating structure represented by a tetrasaccharide consisting of a linear trisaccharide fragment of α-L-Rhap residues in the main chain and the terminal β-D-Glcp residue. The structure of this O-specific polysaccharide was identical to the previously determined structure of the capsular polysaccharide of these bacteria grown without quercetin. Modifications in the structural composition of the capsular polysaccharide induced by cultivation in the presence of quercetin were revealed.

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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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. Copyright © 2010 Elsevier GmbH. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    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 + }.

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

    Science.gov (United States)

    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 + .

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Wisniewski-Dyé, Florence; Lozano, Luis; Acosta-Cruz, Erika; Borland, Stéphanie; Drogue, Benoît; Prigent-Combaret, Claire; Rouy, Zoé; Barbe, Valérie; Mendoza Herrera, Alberto; González, Victor; Mavingui, Patrick

    2012-01-01

    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. PMID:24705077

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

    Directory of Open Access Journals (Sweden)

    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.

  1. 12 CFR 269b.510 - Review by panel.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Review by panel. 269b.510 Section 269b.510... CHARGES OF UNFAIR LABOR PRACTICES Panel Review of Hearing Officer's Report and Recommended Decision § 269b.510 Review by panel. The panel shall review the report and recommendations of each hearing officer...

  2. Kandungan Nitrogen dan Bobot Biji Kentang yang Diberi Pupuk Organik Difermentasi, Azospirillum sp., dan Pupuk Nitrogen di Cisarua, Lembang, Jawa Barat

    OpenAIRE

    Nurmayulis; Maryati

    2008-01-01

    A research was conducted to study response of potato (Solanum tuberosum L.) plant to the application of fermented organic matter (‘porasi’) (0, 7.5, 15.0, and 22.5 t ha-1), without or with inoculation of Azospirillum sp., and N fertilizer (0, 86, 172, and 258 kg ha-1 N) and also to determine optimal rate of application of ‘porasi’ and N fertilizer without or with inoculant Azospirillum sp. Field experiments were carried out in Cisarua, Lembang West Java, from June to November 2003. The...

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

    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

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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: Copyright © 2012. Published by Elsevier Ltd.

  5. Tuber growth rate and P-content of potato applied with fermented organic matter Azospirillum sp., and N-fertilizer

    OpenAIRE

    Nurmayulis; Maryati

    2011-01-01

    A research was conducted to study P-uptake of potato (Solanum tuberosum L.) responding to application of fermented organic matter and also to determine tuber growth rate. Field experiment was carried out in Pangalengan and Cisarua, Lembang, from June to November 2003. It was set up in a 3-factor randomized complete block design with three replications. First factor was rate of fermented organic matter (0, 7.5, 15.0, and 22.5 t ha-1). Second one was Azospirillum sp. (no and with...

  6. Genome-wide survey of two-component signal transduction systems in the plant growth-promoting bacterium Azospirillum.

    Science.gov (United States)

    Borland, Stéphanie; Oudart, Anne; Prigent-Combaret, Claire; Brochier-Armanet, Céline; Wisniewski-Dyé, Florence

    2015-10-22

    Two-component systems (TCS) play critical roles in sensing and responding to environmental cues. Azospirillum is a plant growth-promoting rhizobacterium living in the rhizosphere of many important crops. Despite numerous studies about its plant beneficial properties, little is known about how the bacterium senses and responds to its rhizospheric environment. The availability of complete genome sequenced from four Azospirillum strains (A. brasilense Sp245 and CBG 497, A. lipoferum 4B and Azospirillum sp. B510) offers the opportunity to conduct a comprehensive comparative analysis of the TCS gene family. Azospirillum genomes harbour a very large number of genes encoding TCS, and are especially enriched in hybrid histidine kinases (HyHK) genes compared to other plant-associated bacteria of similar genome sizes. We gained further insight into HyHK structure and architecture, revealing an intriguing complexity of these systems. An unusual proportion of TCS genes were orphaned or in complex clusters, and a high proportion of predicted soluble HKs compared to other plant-associated bacteria are reported. Phylogenetic analyses of the transmitter and receiver domains of A. lipoferum 4B HyHK indicate that expansion of this family mainly arose through horizontal gene transfer but also through gene duplications all along the diversification of the Azospirillum genus. By performing a genome-wide comparison of TCS, we unraveled important 'genus-defining' and 'plant-specifying' TCS. This study shed light on Azospirillum TCS which may confer important regulatory flexibility. Collectively, these findings highlight that Azospirillum genomes have broad potential for adaptation to fluctuating environments.

  7. 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.

  8. AZOSPIRILLUM BRASILENSE VIA FOLIAR E DOSES DE NITROGÊNIO EM COBERTURA NA CULTURA DO TRIGO NA REGIÃO DE ITAPEVA-SP / SPRAYING WITH AZOSPIRILLUM ON WHEAT LEAF AND NITROGEN COVERAGE RATES IN ITAPEVA-SP

    Directory of Open Access Journals (Sweden)

    J. P. Ferreira

    2017-06-01

    Full Text Available A utilização de bactérias diazotróficas na agricultura, especialmente em gramíneas, tem por finalidade incrementar a produção e produtividade aliando com menor dose ou supressão das fontes nitrogenadas aplicadas para fertilização do solo. Diante disso, o trabalho objetivou avaliar a viabilidade da inoculação de Azospirillum brasilense via foliar com doses de nitrogênio em cobertura na produção e produtividade do trigo. O experimento foi implantado na Fazenda Bom Viver, Bairro dos Prestes em Itapeva-SP, na safra de 2016, sendo realizado em plantio direto (SPC em área de sucessão soja e milho safrinha. Os tratamentos foram em esquema fatorial 2x4 em blocos ao acaso (DBC sendo aplicado a formulação liquida de Azospirillum brasiliense (AbV5 com 2x108 células viáveis mL-1 na dose de 0,5 L.ha-1 via foliar e sem aplicação e posterior adubação nitrogenada com 0; 30; 60 e 90 kg.ha-1 em cobertura. Tanto a aplicação foliar de Azospirillum como a cobertura de N, foram aplicadas após 30 dias da semeadura (30 DAS. A variedade de trigo utilizada no plantio foi o Sinuelo, com manejo adotado pelo proprietário da área com aplicação de regulador de crescimento. Foram realizadas as avaliações a campo das plantas, medindo-se: a altura das plantas; espigas por metro linear; número de grãos por espiguetas; peso hectolítro; massa de mil grãos e produtividade. Pelos resultados obtidos, houve maior altura de plantas com o aumento das doses de nitrogênio em cobertura. A inoculação de Azospirillum brasiliense via foliar não mostrou interação entre as doses de nitrogênio em cobertura, não havendo estatisticamente incremento nos componentes de produtividade do trigo.

  9. 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.

  10. 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.

  11. [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.

  12. Carotenoid Biosynthetic Pathways Are Regulated by a Network of Multiple Cascades of Alternative Sigma Factors in Azospirillum brasilense Sp7.

    Science.gov (United States)

    Rai, Ashutosh Kumar; Dubey, Ashutosh Prakash; Kumar, Santosh; Dutta, Debashis; Mishra, Mukti Nath; Singh, Bhupendra Narain; Tripathi, Anil Kumar

    2016-11-01

    Carotenoids constitute an important component of the defense system against photooxidative stress in bacteria. In Azospirillum brasilense Sp7, a nonphotosynthetic rhizobacterium, carotenoid synthesis is controlled by a pair of extracytoplasmic function sigma factors (RpoEs) and their cognate zinc-binding anti-sigma factors (ChrRs). Its genome harbors two copies of the gene encoding geranylgeranyl pyrophosphate synthase (CrtE), the first critical step in the carotenoid biosynthetic pathway in bacteria. Inactivation of each of two crtE paralogs found in A. brasilense caused reduction in carotenoid content, suggesting their involvement in carotenoid synthesis. However, the effect of crtE1 deletion was more pronounced than that of crtE2 deletion. Out of the five paralogs of rpoH in A. brasilense, overexpression of rpoH1 and rpoH2 enhanced carotenoid synthesis. Promoters of crtE2 and rpoH2 were found to be dependent on RpoH2 and RpoE1, respectively. Using a two-plasmid system in Escherichia coli, we have shown that the crtE2 gene of A. brasilense Sp7 is regulated by two cascades of sigma factors: one consisting of RpoE1and RpoH2 and the other consisting of RpoE2 and RpoH1. In addition, expression of crtE1 was upregulated indirectly by RpoE1 and RpoE2. This study shows, for the first time in any carotenoid-producing bacterium, that the regulation of carotenoid biosynthetic pathway involves a network of multiple cascades of alternative sigma factors. Carotenoids play a very important role in coping with photooxidative stress in prokaryotes and eukaryotes. Although extracytoplasmic function (ECF) sigma factors are known to directly regulate the expression of carotenoid biosynthetic genes in bacteria, regulation of carotenoid biosynthesis by one or multiple cascades of sigma factors had not been reported. This study provides the first evidence of the involvement of multiple cascades of sigma factors in the regulation of carotenoid synthesis in any bacterium by showing the

  13. In silico comparative analysis of GGDEF and EAL domain signaling proteins from the Azospirillum genomes.

    Science.gov (United States)

    Mata, Alberto Ramírez; Pacheco, César Millán; Cruz Pérez, José F; Sáenz, Martha Minjárez; Baca, Beatriz E

    2018-03-09

    The cyclic-di-GMP (c-di-GMP) second messenger exemplifies a signaling system that regulates many bacterial behaviors of key importance; among them, c-di-GMP controls the transition between motile and sessile life-styles in bacteria. Cellular c-di-GMP levels in bacteria are regulated by the opposite enzymatic activities of diguanylate cyclases and phosphodiesterases, which are proteins that have GGDEF and EAL domains, respectively. Azospirillum is a genus of plant-growth-promoting bacteria, and members of this genus have beneficial effects in many agronomically and ecologically essential plants. These bacteria also inhabit aquatic ecosystems, and have been isolated from humus-reducing habitats. Bioinformatic and structural approaches were used to identify genes predicted to encode GG[D/E]EF, EAL and GG[D/E]EF-EAL domain proteins from nine genome sequences. The analyzed sequences revealed that the genomes of A. humicireducens SgZ-5 T , A. lipoferum 4B, Azospirillum sp. B510, A. thiophilum BV-S T , A. halopraeferens DSM3675, A. oryzae A2P, and A. brasilense Sp7, Sp245 and Az39 encode for 29 to 41 of these predicted proteins. Notably, only 15 proteins were conserved in all nine genomes: eight GGDEF, three EAL and four GGDEF-EAL hybrid domain proteins, all of which corresponded to core genes in the genomes. The predicted proteins exhibited variable lengths, architectures and sensor domains. In addition, the predicted cellular localizations showed that some of the proteins to contain transmembrane domains, suggesting that these proteins are anchored to the membrane. Therefore, as reported in other soil bacteria, the Azospirillum genomes encode a large number of proteins that are likely involved in c-di-GMP metabolism. In addition, the data obtained here strongly suggest host specificity and environment specific adaptation. Bacteria of the Azospirillum genus cope with diverse environmental conditions to survive in soil and aquatic habitats and, in certain cases, to

  14. 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.

  15. 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.

  16. 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. Copyright © 2010 Elsevier GmbH. All rights reserved.

  17. [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.

  18. Chromosomal flhB1 gene of the alphaproteobacterium Azospirillum brasilense Sp245 is essential for correct assembly of both constitutive polar flagellum and inducible lateral flagella.

    Science.gov (United States)

    Filip'echeva, Yulia; Shelud'ko, Andrei; Prilipov, Alexei; Telesheva, Elizaveta; Mokeev, Dmitry; Burov, Andrei; Petrova, Lilia; Katsy, Elena

    2018-03-01

    Azospirillum brasilense has the ability of swimming and swarming motility owing to the work of a constitutive polar flagellum and inducible lateral flagella, respectively. The interplay between these flagellar systems is poorly understood. One of the key elements of the flagellar export apparatus is the protein FlhB. Two predicted flhB genes are present in the genome of A. brasilense Sp245 (accession nos. HE577327-HE577333). Experimental evidence obtained here indicates that the chromosomal coding sequence (CDS) AZOBR_150177 (flhB1) of Sp245 is essential for the production of both types of flagella. In an flhB1:: Omegon-Km mutant, Sp245.1063, defects in polar and lateral flagellar assembly and motility were complemented by expressing the wild-type flhB1 gene from plasmid pRK415. It was found that Sp245.1063 lost the capacity for slight but statistically significant decrease in mean cell length in response to transfer from solid to liquid media, and vice versa; in the complemented mutant, this capacity was restored. It was also shown that after the acquisition of the pRK415-harbored downstream CDS AZOBR_150176, cells of Sp245 and Sp245.1063 ceased to elongate on solid media. These initial data suggest that the AZOBR_150176-encoded putative multisensory hybrid sensor histidine kinase-response regulator, in concert with FlhB1, plays a role in morphological response of azospirilla to changes in the hardness of a milieu.

  19. Aislamiento e identificación de cepas de Azospirillum sp. en pasto guinea (Panicum maximum Jacq. del Valle del Cesar Isolation and identification of Azospirillum sp. in Guinea grass (Panicum maximum Jacq. of the Valle del Cesar

    Directory of Open Access Journals (Sweden)

    Diana M Cárdenas

    2010-09-01

    Full Text Available Se evaluó el efecto de factores ambientales del Valle del Cesar y el manejo agronómico del pasto guinea (Panicum maximum Jacq., sobre la población bacteriana del género Azospirillum en medios de cultivo semisólidos NFb y LGI, para lo cual se utilizó un diseño experimental en parcelas divididas con un arreglo factorial de 2 (épocas climáticas: lluvia y sequía x 2 (manejos agronómicos: agroecólogico y extractivo x 3 (muestras analizadas: suelo rizosférico, raíces y hojas. Los resultados no revelaron diferencias estadísticas significativas, lo que indica que esta bacteria puede mantener su población en condiciones de estrés por diferentes mecanismos fisiológicos. A partir de estas muestras se obtuvieron 16 aislamientos pertenecientes al género Azospirillum, a los cuales se les evaluó su actividad de reducción de acetileno como indicador de la fijación biológica de nitrógeno y su capacidad en la producción de compuestos indólicos como promotores del crecimiento vegetal. Se seleccionaron las cepas SRGM2, SRGM3 y SRGM4 obtenidas de muestras de suelo rizosférico de pasto guinea de la Estación Experimental Motilonia de Corpoica, municipio Agustín Codazzi, departamento del Cesar. Estos aislamientos se caracterizaron molecularmente por el gen 16S rRNA y según el análisis BLAST en la base de datos del GenBank y presentaron 93% de similitud con A. lipoferum (SRGM2 y SRGM3 y 94% con A. brasilense (SRGM4.The effect of environmental factors of the Valle del Cesar and the agronomic management of Guinea grass (Panicum maximum Jacq., on the bacterial population of the Azospirillum genus in semisolid NFb and LGI culture media was evaluated, for which an experimental design was used in divided plots with a 2 (climatic seasons: rainy and dry x 2 (agronomic managements: agroecological and extractive x 3 (analyzed samples: rhizospheric soil, roots and leaves factorial arrangement. The results did not reveal significant statistical

  20. Nitrogen Fixation Associated with Development and Localization of Mixed Populations of Cellulomonas sp. and Azospirillum brasilense Grown on Cellulose or Wheat Straw

    Science.gov (United States)

    Halsall, Dorothy M.; Goodchild, David J.

    1986-01-01

    Mixed cultures of Cellulomonas sp. and Azospirillum brasilense were grown with straw or cellulose as the carbon source under conditions favoring the fixation of atmospheric nitrogen. Rapid increases in cell numbers, up to 109 cells per g of substrate, were evident after 4 and 5 days of incubation at 30°C for cellulose and straw, respectively. Nitrogen fixation (detected by acetylene reduction measured on parallel cultures) commenced after 2 and 4 days of incubation for straw and cellulose, respectively, and continued for the duration of the experiment. Pure cultures of Cellulomonas sp. showed an increase in cell numbers, but CO2 production was low, and acetylene reduction was not detected on either cellulose or straw. Pure cultures of A. brasilense on cellulose showed an initial increase in cell numbers (107 cells per g of substrate) over 4 days, followed by a decline presumably caused by the exhaustion of available carbon substrate. On straw, A. brasilense increased to 109 cells per g of substrate over 5 days and then declined slowly; this growth was accompanied by acetylene reduction. Scanning electron micrographs of straw incubated with a mixed culture under the above conditions for 8 days showed cells of both species in close proximity to each other. Evidence was furnished that the close spatial relationship of cells from the two species facilitated the mutually beneficial association between them and thus increased the efficiency with which the products of straw breakdown were used for nitrogen fixation. Images PMID:16347042

  1. 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.

  2. The ntrB and ntrC Genes Are Involved in the Regulation of Poly-3-Hydroxybutyrate Biosynthesis by Ammonia in Azospirillum brasilense Sp7

    Science.gov (United States)

    Sun, Jun; Peng, Xuan; Van Impe, Jan; Vanderleyden, Jos

    2000-01-01

    Azospirillum brasilense Sp7 and its ntrA (rpoN), ntrBC, and ntrC mutants have been evaluated for their capabilities of poly-3-hydroxybutyrate (PHB) accumulation in media with high and low ammonia concentrations. It was observed that the ntrBC and ntrC mutants can produce PHB in both low- and high-C/N-ratio media, while no significant PHB production was observed for the wild type or the ntrA mutant in low-C/N-ratio media. Further investigation by fermentation analysis indicated that the ntrBC and ntrC mutants were able to grow and accumulate PHB simultaneously in the presence of a high concentration of ammonia in the medium, while little PHB was produced in the wild type and ntrA (rpoN) mutant during active growth phase. These results provide the first genetic evidence that the ntrB and ntrC genes are involved in the regulation of PHB synthesis by ammonia in A. brasilense Sp7. PMID:10618211

  3. 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

  4. Expression of alkyl hydroperoxide reductase is regulated negatively by OxyR1 and positively by RpoE2 sigma factor in Azospirillum brasilense Sp7.

    Science.gov (United States)

    Singh, Sudhir; Dwivedi, Susheel Kumar; Singh, Vijay Shankar; Tripathi, Anil Kumar

    2016-10-01

    OxyR proteins are LysR-type transcriptional regulators, which play an important role in responding to oxidative stress in bacteria. Azospirillum brasilense Sp7 harbours two copies of OxyR. The inactivation of the oxyR1, the gene organized divergently to ahpC in A. brasilense Sp7, led to an increased tolerance to alkyl hydroperoxides, which was corroborated by an increase in alkyl hydroperoxide reductase (AhpC) activity, enhanced expression of ahpC :lacZ fusion and increased synthesis of AhpC protein in the oxyR1::km mutant. The upstream region of ahpC promoter harboured a putative OxyR binding site, T-N11-A. Mutation of T, A or both in the T-N11-Amotif caused derepression of ahpC in A. brasilense suggesting that T-N11-A might be the binding site for a negative regulator. Retardation of the electrophoretic mobility of the T-N11-A motif harbouring oxyR1-ahpC intergenic DNA by recombinant OxyR1, under reducing as well as oxidizing conditions, indicated that OxyR1 acts as a negative regulator of ahpC in A. brasilense. Sequence of the promoter of ahpC, predicted on the basis of transcriptional start site, and an enhanced expression of ahpC:lacZ fusion in chrR2::km mutant background suggested that ahpC promoter was RpoE2 dependent. Thus, this study shows that in A. brasilense Sp7, ahpC expression is regulated negatively by OxyR1 but is regulated positively by RpoE2, an oxidative-stress-responsive sigma factor. It also shows that OxyR1 regulates the expression RpoE1, which is known to play an important role during photooxidative stress in A. brasilense.

  5. 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.

  6. 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 (Co2+, Cu2+ and Zn2+) 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.

  7. Early plant growth and biochemical responses induced by Azospirillum brasilense Sp245 lipopolysaccharides in wheat (Triticum aestivum L.) seedlings are attenuated by procyanidin B2.

    Science.gov (United States)

    Vallejo-Ochoa, Juan; López-Marmolejo, Mariel; Hernández-Esquivel, Alma Alejandra; Méndez-Gómez, Manuel; Suárez-Soria, Laura Nicolasa; Castro-Mercado, Elda; García-Pineda, Ernesto

    2018-03-01

    This study analyzes the effects of procyanidin B2 on early wheat plant growth and plant biochemical responses promoted by lipopolysaccharides (LPS) derived from the rhizobacteria Azospirillum brasilense Sp245. Measurements of leaf, root length, fresh weight, and dry weight showed in vitro plant growth stimulation 4 days after treatment with A. brasilense as well as LPS. Superoxide anion (O 2 ·- ) and hydrogen peroxide (H 2 O 2 ) levels increased in seedling roots treated with LPS (100 μg mL -1 ). The chlorophyll content in leaf decreased while the starch content increased 24 h after treatment in seedling roots. The LPS treatment induced a high increase in total peroxidase (POX) (EC 1.11.1.7) activity and ionically bound cell wall POX content in roots, when compared to respective controls. Early plant growth and biochemical responses observed in wheat seedlings treated with LPS were inhibited by the addition of procyanidin B2 (5 μg mL -1 ), a B type proanthocyanidin (PAC), plant-derived polyphenolic compound with binding properties of LPS. All results suggest first that the ionically bound cell wall POX enzymes could be a molecular target of A. brasilense LPS, and second that the recognition or association of LPS by plant cells is required to activate plant responses. This last event could play a critical role during plant growth regulation by A. brasilense LPS.

  8. 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.

  9. 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.

  10. FTIR spectroscopic studies of selenite reduction by cells of the rhizobacterium Azospirillum brasilense Sp7 and the formation of selenium nanoparticles

    Science.gov (United States)

    Kamnev, Alexander A.; Mamchenkova, Polina V.; Dyatlova, Yulia A.; Tugarova, Anna V.

    2017-07-01

    Microbially driven reduction of selenium oxyanions to elementary selenium, often in the form of nanoparticles (NPs), is widespread in nature. A diversity of possible applications of such biogenic NPs, including those in nanobiotechnology, as well as the specificity of methodologies and mechanisms of their formation via ;green synthesis; are very attractive features justifying further studies of the processes of selenium oxyanion bioreduction and the resulting Se0 nanostructures. In this study, live biomass of the rhizobacterium Azospirillum brasilense Sp7 (harvested after the logarithmic growth phase and washed from culture medium components) was used to obtain extracellular Se NPs relatively homogeneous in size (with average diameters within 50-100 nm) in the process of selenite reduction. Both the control cultures of A. brasilense Sp7 and those incubated with SeO32- (producing Se NPs), as well as the resulting separated Se NPs were studied using Fourier transform infrared (FTIR) spectroscopy in the transmission mode (measured as dried layers on a ZnSe disc), in addition to transmission electron microscopy (TEM), to compare metabolic changes in cells and the bioorganic layers associated with the Se NPs. In the control culture (stored for 24 h in physiological saline), FTIR spectroscopic signs of poly-3-hydroxybutyrate (a 'reserve' biopolyester) were observed as a response to the lack of nutrients (trophic stress), whereas they were virtually absent in cells incubated for 24 h in physiological saline with 10 mM SeO32- (toxicity stress). FTIR spectra of Se NPs separated from bacterial cells showed bands typical of proteins, polysaccharides and lipids associated with the particles (in line with their TEM images showing a thin layer over the NPs), in addition to strong carboxylate bands, which evidently stabilise the NP structure and morphology.

  11. [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.

  12. Distinct Domains of CheA Confer Unique Functions in Chemotaxis and Cell Length in Azospirillum brasilense Sp7.

    Science.gov (United States)

    Gullett, Jessica M; Bible, Amber; Alexandre, Gladys

    2017-07-01

    Chemotaxis is the movement of cells in response to gradients of diverse chemical cues. Motile bacteria utilize a conserved chemotaxis signal transduction system to bias their motility and navigate through a gradient. A central regulator of chemotaxis is the histidine kinase CheA. This cytoplasmic protein interacts with membrane-bound receptors, which assemble into large polar arrays, to propagate the signal. In the alphaproteobacterium Azospirillum brasilense , Che1 controls transient increases in swimming speed during chemotaxis, but it also biases the cell length at division. However, the exact underlying molecular mechanisms for Che1-dependent control of multiple cellular behaviors are not known. Here, we identify specific domains of the CheA1 histidine kinase implicated in modulating each of these functions. We show that CheA1 is produced in two isoforms: a membrane-anchored isoform produced as a fusion with a conserved seven-transmembrane domain of unknown function (TMX) at the N terminus and a soluble isoform similar to prototypical CheA. Site-directed and deletion mutagenesis combined with behavioral assays confirm the role of CheA1 in chemotaxis and implicate the TMX domain in mediating changes in cell length. Fluorescence microscopy further reveals that the membrane-anchored isoform is distributed around the cell surface while the soluble isoform localizes at the cell poles. Together, the data provide a mechanism for the role of Che1 in controlling multiple unrelated cellular behaviors via acquisition of a new domain in CheA1 and production of distinct functional isoforms. IMPORTANCE Chemotaxis provides a significant competitive advantage to bacteria in the environment, and this function has been transferred laterally multiple times, with evidence of functional divergence in different genomic contexts. The molecular principles that underlie functional diversification of chemotaxis in various genomic contexts are unknown. Here, we provide a molecular

  13. 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.

  14. Regulation of a Glycerol-Induced Quinoprotein Alcohol Dehydrogenase by σ54and a LuxR-Type Regulator in Azospirillum brasilense Sp7.

    Science.gov (United States)

    Singh, Vijay Shankar; Dubey, Ashutosh Prakash; Gupta, Ankush; Singh, Sudhir; Singh, Bhupendra Narain; Tripathi, Anil Kumar

    2017-07-01

    Azospirillum brasilense Sp7 uses glycerol as a carbon source for growth and nitrogen fixation. When grown in medium containing glycerol as a source of carbon, it upregulates the expression of a protein which was identified as quinoprotein alcohol dehydrogenase (ExaA). Inactivation of exaA adversely affects the growth of A. brasilense on glycerol. A determination of the transcription start site of exaA revealed an RpoN-dependent -12/-24 promoter consensus. The expression of an exaA :: lacZ fusion was induced maximally by glycerol and was dependent on σ 54 Bioinformatic analysis of the sequence flanking the -12/-24 promoter revealed a 17-bp sequence motif with a dyad symmetry of 6 nucleotides upstream of the promoter, the disruption of which caused a drastic reduction in promoter activity. The electrophoretic mobility of a DNA fragment containing the 17-bp sequence motif was retarded by purified EraR, a LuxR-type transcription regulator that is transcribed divergently from exaA EraR also showed a positive interaction with RpoN in two-hybrid and pulldown assays. IMPORTANCE Quinoprotein alcohol dehydrogenase (ExaA) plays an important role in the catabolism of alcohols in bacteria. Although exaA expression is thought to be regulated by a two-component system consisting of EraS and EraR, the mechanism of regulation was not known. This study shows the details of the regulation of expression of the exaA gene in A. brasilense We have shown here that exaA of A. brasilense is maximally induced by glycerol and harbors a σ 54 -dependent promoter. The response regulator EraR binds to an inverted repeat located upstream of the exaA promoter. This study shows that a LuxR-type response regulator (EraR) binds upstream of the exaA gene and physically interacts with σ 54 The unique feature of this regulation is that EraR is a LuxR-type transcription regulator that lacks the GAFTGA motif, a characteristic feature of the enhancer binding proteins that are known to interact with σ 54

  15. [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.

  16. Plasmid AZOBR_p1-borne fabG gene for putative 3-oxoacyl-[acyl-carrier protein] reductase is essential for proper assembly and work of the dual flagellar system in the alphaproteobacterium Azospirillum brasilense Sp245.

    Science.gov (United States)

    Filip'echeva, Yulia A; Shelud'ko, Andrei V; Prilipov, Alexei G; Burygin, Gennady L; Telesheva, Elizaveta M; Yevstigneyeva, Stella S; Chernyshova, Marina P; Petrova, Lilia P; Katsy, Elena I

    2018-02-01

    Azospirillum brasilense can swim and swarm owing to the activity of a constitutive polar flagellum (Fla) and inducible lateral flagella (Laf), respectively. Experimental data on the regulation of the Fla and Laf assembly in azospirilla are scarce. Here, the coding sequence (CDS) AZOBR_p1160043 (fabG1) for a putative 3-oxoacyl-[acyl-carrier protein (ACP)] reductase was found essential for the construction of both types of flagella. In an immotile leaky Fla - Laf - fabG1::Omegon-Km mutant, Sp245.1610, defects in flagellation and motility were fully complemented by expressing the CDS AZOBR_p1160043 from plasmid pRK415. When pRK415 with the cloned CDS AZOBR_p1160045 (fliC) for a putative 65.2 kDa Sp245 Fla flagellin was transferred into the Sp245.1610 cells, the bacteria also became able to assemble a motile single flagellum. Some cells, however, had unusual swimming behavior, probably because of the side location of the organelle. Although the assembly of Laf was not restored in Sp245.1610 (pRK415-p1160045), this strain was somewhat capable of swarming motility. We propose that the putative 3-oxoacyl-[ACP] reductase encoded by the CDS AZOBR_p1160043 plays a role in correct flagellar location in the cell envelope and (or) in flagellar modification(s), which are also required for the inducible construction of Laf and for proper swimming and swarming motility of A. brasilense Sp245.

  17. [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.

  18. Development of alginate-based aggregate inoculants of Methylobacterium sp. and Azospirillum brasilense tested under in vitro conditions to promote plant growth.

    Science.gov (United States)

    Joe, M M; Saravanan, V S; Islam, M R; Sa, T

    2014-02-01

    To develop co-aggregated bacterial inoculant comprising of Methylobacterium oryzae CBMB20/Methylobacterium suomiense CBMB120 strains with Azospirillum brasilense (CW903) strain and testing their efficiency as inoculants for plant growth promotion (PGP). Biofilm formation and co-aggregation efficiency was studied between A. brasilense CW903 and methylobacterial strains M. oryzae CBMB20 and M. suomiense CBMB120. Survival and release of these co-aggregated bacterial strains entrapped in alginate beads were assessed. PGP attributes of the co-aggregated bacterial inoculant were tested in tomato plants under water-stressed conditions. Results suggest that the biofilm formation efficiency of the CBMB20 and CBMB120 strains increased by 15 and 34%, respectively, when co-cultivated with CW903. Co-aggregation with CW903 enhanced the survivability of CBMB20 strain in alginate beads. Water stress index score showed least stress index in plants inoculated with CW903 and CBMB20 strains maintained as a co-aggregated inoculant. This study reports the development of co-aggregated cell inoculants containing M. oryzae CBMB20 and A. brasilense CW903 strains conferred better shelf life and stress abatement in inoculated tomato plants. These findings could be extended to other PGP bacterial species to develop multigeneric bioinoculants with multiple benefits for various crops. © 2013 The Society for Applied Microbiology.

  19. 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.

  20. 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.

  1. 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.

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

    Science.gov (United States)

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

    2010-07-04

    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 (gamma-CAs) are widespread in prokaryotes but their physiological roles remain elusive. At present, only gamma-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 beta-CA and two gamma-CAs. One of the putative gamma-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-gamma-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. This study shows lack of CO2 hydration activity in a recombinant protein expressed from a gene predicted to encode a gamma-carbonic anhydrase in A. brasilense although it cross reacts with anti-Cam antibody raised against a well characterized gamma-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.

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

    Science.gov (United States)

    2010-01-01

    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. PMID:20598158

  4. 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.

  5. 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.

  6. 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.

  7. Root phospholipids in Azospirillum-inoculated wheat seedlings exposed to water stress.

    Science.gov (United States)

    Pereyra, M A; Zalazar, C A; Barassi, C A

    2006-01-01

    Azospirillum-plant association is accompanied by biochemical changes in roots which, in turn, promote plant-growth and tolerance to water stress. To shed light on the possible factors underlying these effects, roots from Azospirillum brasilense Sp245-inoculated Triticum aestivum seedlings growing in darkness under osmotic stress were analyzed for phospholipid (PL) composition, fatty acid (FA) distribution profiles and degree of unsaturation of the major PL classes. Azospirillum inoculation diminished ion leakage and increased 2,3,5-tripheniltetrazolium reducing ability in roots of well irrigated and water-stressed wheat seedlings. Total root PL content remained unaltered in all treatments. Six PL classes were detected, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) comprising over 80% of the total. While water stress increased PC content and diminished that of PE, none of these changes were observed either under Azospirillum inoculation alone or when both treatments were combined. The major FAs found in both PC and PE were 16:0, 18:0, 18:1, 18:2, and 18:3. Higher PC and lower PE unsaturation than in well irrigated controls were observed in roots from Azospirillum-inoculated, water-stressed seedlings. Azospirillum inoculation could contribute to protect wheat seedlings from water stress through changes in the FA distribution profiles of PC and PE major root phospholipids.

  8. [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.

  9. Chemotaxis of Azospirillum species to aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-de-Victoria, G.; Lovell, C.R. (Univ. of South Carolina, Columbia, SC (United States))

    1993-09-01

    Azospirillum sspeciesare free-living nitrogen fixing bacteria commonly found in soils and in association with plant roots, including important agricultural crops. Rhizosphere colonization my Azospirillum species has been shown to stimulate growth of a variety of plant species. Chemotaxis is one of the properties which may contribute to survival, rhizosphere colonization and the initiation of mutualistic interactions by Azospirillum species. This study evaluates the chemotactic responses of three Azospirillum stains to a variety of aromatic compounds:benzoate, catechol, 4-HB, and PCA. Results indicate that the same aromatic substance can elicit different chemotactic responses from different Azospirillum species, and that Azospirillum can detect aromatic substrates at concentrations similar to those they encounter naturally. 36 refs., 1 fig., 6 tabs.

  10. Comparison of Two Cellulomonas Strains and Their Interaction with Azospirillum brasilense in Degradation of Wheat Straw and Associated Nitrogen Fixation

    OpenAIRE

    Halsall, Dorothy M.; Gibson, Alan H.

    1986-01-01

    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 CSI-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 (C2H2 reduction)...

  11. 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. © 2014 Scandinavian Plant Physiology Society.

  12. 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.

  13. 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.

  14. Genome Structure of the Genus Azospirillum

    Science.gov (United States)

    Martin-Didonet, Claudia C. G.; Chubatsu, Leda S.; Souza, Emanuel M.; Kleina, Margareth; Rego, Fabiane G. M.; Rigo, Liu U.; Yates, M. Geoffrey; Pedrosa, Fabio O.

    2000-01-01

    Azospirillum species are plant-associated diazotrophs of the alpha subclass of Proteobacteria. The genomes of five of the six Azospirillum species were analyzed by pulsed-field gel electrophoresis. All strains possessed several megareplicons, some probably linear, and 16S ribosomal DNA hybridization indicated multiple chromosomes in genomes ranging in size from 4.8 to 9.7 Mbp. The nifHDK operon was identified in the largest replicon. PMID:10869094

  15. Comparison of prominent Azospirillum strains in Azospirillum-Pseudomonas-Glomus consortia for promotion of maize growth.

    Science.gov (United States)

    Couillerot, Olivier; Ramírez-Trujillo, Augusto; Walker, Vincent; von Felten, Andreas; Jansa, Jan; Maurhofer, Monika; Défago, Geneviève; Prigent-Combaret, Claire; Comte, Gilles; Caballero-Mellado, Jesus; Moënne-Loccoz, Yvan

    2013-05-01

    Azospirillum are prominent plant growth-promoting rhizobacteria (PGPR) extensively used as phytostimulatory crop inoculants, but only few studies are dealing with Azospirillum-containing mixed inocula involving more than two microorganisms. We compared here three prominent Azospirillum strains as part of three-component consortia including also the PGPR Pseudomonas fluorescens F113 and a mycorrhizal inoculant mix composed of three Glomus strains. Inoculant colonization of maize was assessed by quantitative PCR, transcription of auxin synthesis gene ipdC (involved in phytostimulation) in Azospirillum by RT-PCR, and effects on maize by secondary metabolic profiling and shoot biomass measurements. Results showed that phytostimulation by all the three-component consortia was comparable, despite contrasted survival of the Azospirillum strains and different secondary metabolic responses of maize to inoculation. Unexpectedly, the presence of Azospirillum in the inoculum resulted in lower phytostimulation in comparison with the Pseudomonas-Glomus two-component consortium, but this effect was transient. Azospirillum's ipdC gene was transcribed in all treatments, especially with three-component consortia, but not with all plants and samplings. Inoculation had no negative impact on the prevalence of mycorrhizal taxa in roots. In conclusion, this study brought new insights in the functioning of microbial consortia and showed that Azospirillum-Pseudomonas-Glomus three-component inoculants may be useful in environmental biotechnology for maize growth promotion.

  16. Carotenoid production and phenotypic variation in Azospirillum brasilense.

    Science.gov (United States)

    Brenholtz, Gal Reem; Tamir-Ariel, Dafna; Okon, Yaacov; Burdman, Saul

    2017-06-01

    We assessed the occurrence of phenotypic variation in Azospirillum brasilense strains Sp7, Cd, Sp245, Az39 and phv2 during growth in rich media, screening for variants altered in colony pigmentation or extracellular polysaccharide (EPS) production. Previous studies showed that EPS-overproducing variants of Sp7 appear frequently following starvation or growth in minimal medium. In contrast, no such variants were detected during growth in rich media in the tested strains except for few variants of phv2. Regarding alteration in colony pigmentation (from pink to white in strain Cd and from white to pink in the others), strain Sp7 showed a relatively high frequency of variation (0.009-0.026%). Strain Cd showed a lower frequency of alteration in pigmentation (0-0.008%), and this type of variation was not detected in the other strains. In A. brasilense, carotenoid synthesis is controlled by two RpoE sigma factors and their cognate ChrR anti-sigma factors, the latter acting as negative regulators of carotenoid synthesis. Here, all tested (n = 28) pink variants of Sp7 carried mutations in one of the anti-sigma factor genes, chrR1. Our findings indicate that, in A. brasilense, phenotypic variation is strain- and environment-dependent and support the central role of ChrR1 in regulation of carotenoid production. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  17. Applicability of the 16S-23S rDNA internal spacer for PCR detection of the phytostimulatory PGPR inoculant Azospirillum lipoferum CRT1 in field soil.

    Science.gov (United States)

    Baudoin, E; Couillerot, O; Spaepen, S; Moënne-Loccoz, Y; Nazaret, S

    2010-01-01

    To assess the applicability of the 16S-23S rDNA internal spacer regions (ISR) as targets for PCR detection of Azospirillum ssp. and the phytostimulatory plant growth-promoting rhizobacteria seed inoculant Azospirillum lipoferum CRT1 in soil. Primer sets were designed after sequence analysis of the ISR of A. lipoferum CRT1 and Azospirillum brasilense Sp245. The primers fAZO/rAZO targeting the Azospirillum genus successfully yielded PCR amplicons (400-550 bp) from Azospirillum strains but also from certain non-Azospirillum strains in vitro, therefore they were not appropriate to monitor indigenous Azospirillum soil populations. The primers fCRT1/rCRT1 targeting A. lipoferum CRT1 generated a single 249-bp PCR product but could also amplify other strains from the same species. However, with DNA extracts from the rhizosphere of field-grown maize, both fAZO/rAZO and fCRT1/rCRT1 primer sets could be used to evidence strain CRT1 in inoculated plants by nested PCR, after a first ISR amplification with universal ribosomal primers. In soil, a 7-log dynamic range of detection (10(2)-10(8) CFU g(-1) soil) was obtained. The PCR primers targeting 16S-23S rDNA ISR sequences enabled detection of the inoculant A. lipoferum CRT1 in field soil. Convenient methods to monitor Azospirillum phytostimulators in the soil are lacking. The PCR protocols designed based on ISR sequences will be useful for detection of the crop inoculant A. lipoferum CRT1 under field conditions.

  18. Comparison of Two Cellulomonas Strains and Their Interaction with Azospirillum brasilense in Degradation of Wheat Straw and Associated Nitrogen Fixation

    Science.gov (United States)

    Halsall, Dorothy M.; Gibson, Alan H.

    1986-01-01

    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 CSI-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 (C2H2 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. PMID:16347043

  19. 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.

  20. sp

    African Journals Online (AJOL)

    Vihar

    adopted as the first line drug. SP has few untoward effects if used carefully in therapeutic doses. Nausea, vomiting, generalized body weakness; diarrhea, skin rashes and hematological reactions are some of the associated side effects. The drug can cause severe skin reactions such as Steven Johnson's syndrome. This.

  1. 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

  2. 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

    2008-01-01

    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 (ΦAb-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 ΦAb-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 ΦAb-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. PMID:18065619

  3. 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.

  4. 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.

  5. Interspecific cooperation: enhanced growth, attachment and strain-specific distribution in biofilms through Azospirillum brasilense-Pseudomonas protegens co-cultivation.

    Science.gov (United States)

    Pagnussat, Luciana A; Salcedo, Florencia; Maroniche, Guillermo; Keel, Christoph; Valverde, Claudio; Creus, Cecilia M

    2016-10-01

    Plant-growth-promoting bacteria belonging to Azospirillum and Pseudomonas genera are major inhabitants of the rhizosphere. Both are increasingly commercialized as crops inoculants. Interspecific interaction in the rhizosphere is critical for inoculants aptness. The objective of this work was to evaluate Azospirillum and Pseudomonas interaction in mixed biofilms by co-cultivation of the model strains Azospirillum brasilense Sp245 and Pseudomonas protegens CHA0. The results revealed enhanced growth of both strains when co-cultured in static conditions. Moreover, Sp245 biofilm formed in plastic surfaces was increased 2-fold in the presence of CHA0. Confocal microscopy revealed highly structured mixed biofilms showing Sp245 mainly on the bottom and CHA0 towards the biofilm surface. In addition, A. brasilense biofilm was thicker and denser when co-cultured with P. protegens. In a colony-colony interaction assay, Sp245 changed nearby CHA0 producing small colony phenotype, which accounts for a diffusible metabolite mediator; though CHA0 spent medium did not affect Sp245 colony phenotype. Altogether, these results point to a cooperative interaction between A. brasilense Sp245 and P. protegens CHA0 in which both strains increase their static growth and produce structured mixed biofilms with a strain-specific distribution. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. 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. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  7. Development of sequence-characterized amplified region (SCAR) markers as a quality standard of inoculants based on Azospirillum.

    Science.gov (United States)

    Reddy Priya, Pasupuleti; Selastin Antony, Raju; Gopalaswamy, Ganesan; Balachandar, Dananjeyan

    2016-04-01

    An attempt was made in this work to develop a strain-level molecular marker for unambiguous authentication of two Azospirillum inoculants, viz. A. lipoferum (strain Az204) and A. brasilense (strain Sp7). The sequence-characterized amplified region (SCAR) markers obtained from DNA fingerprints were designed for discrete detection of the strains. The SCAR primers could successfully amplify the target strain without cross-reaction with other Azospirillum strains, native isolates and other inoculants. The detection limit of SCAR primer for Az204 was 8.00 pg of DNA (approximately 10(5) cells per mL), and for Sp7, it was 0.49 pg of DNA (equal to 10(4) cells per mL). A simplified Sephadex G100-based crude DNA extraction protocol developed in this study was found suitable for SCAR marker-based strain authentication. Further, SCAR primers were assessed for simultaneous authentication as well as quantification of commercially prepared Azospirillum inoculants by quantitative real-time PCR (RT-PCR) and most-probable-number PCR (MPN-PCR). The RT-PCR assay can be able to quantify the commercial formulations as equal to culturable MPN method, while MPN-PCR failed for Az204. The SCAR marker-based strain authentication and presumptive quantification developed in the present work can contribute to improving the quality standard of commercial inoculants.

  8. 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.

  9. 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

  10. The Pseudomonas secondary metabolite 2,4-diacetylphloroglucinol is a signal inducing rhizoplane expression of Azospirillum genes involved in plant-growth promotion.

    Science.gov (United States)

    Combes-Meynet, Emeline; Pothier, Joël F; Moënne-Loccoz, Yvan; Prigent-Combaret, Claire

    2011-02-01

    During evolution, plants have become associated with guilds of plant-growth-promoting rhizobacteria (PGPR), which raises the possibility that individual PGPR populations may have developed mechanisms to cointeract with one another on plant roots. We hypothesize that this has resulted in signaling phenomena between different types of PGPR colonizing the same roots. Here, the objective was to determine whether the Pseudomonas secondary metabolite 2,4-diacetylphloroglucinol (DAPG) can act as a signal on Azospirillum PGPR and enhance the phytostimulation effects of the latter. On roots, the DAPG-producing Pseudomonas fluorescens F113 strain but not its phl-negative mutant enhanced the phytostimulatory effect of Azospirillum brasilense Sp245-Rif on wheat. Accordingly, DAPG enhanced Sp245-Rif traits involved in root colonization (cell motility, biofilm formation, and poly-β-hydroxybutyrate production) and phytostimulation (auxin production). A differential fluorescence induction promoter-trapping approach based on flow cytometry was then used to identify Sp245-Rif genes upregulated by DAPG. DAPG enhanced expression of a wide range of Sp245-Rif genes, including genes involved in phytostimulation. Four of them (i.e., ppdC, flgE, nirK, and nifX-nifB) tended to be upregulated on roots in the presence of P. fluorescens F113 compared with its phl-negative mutant. Our results indicate that DAPG can act as a signal by which some beneficial pseudomonads may stimulate plant-beneficial activities of Azospirillum PGPR.

  11. [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.

  12. 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.

  13. [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.

  14. Azospirillum improves lettuce growth and transplant under saline conditions.

    Science.gov (United States)

    Fasciglione, Gabriela; Casanovas, Elda M; Yommi, Alejandra; Sueldo, Rolando J; Barassi, Carlos A

    2012-09-01

    Recent studies have shown that as a plant-growth-promoting rhizobacteria (PGPR), Azospirillum inoculation could contribute to the mitigation of the negative effects caused by salt on lettuce growth. Moreover, the use of PGPR to alleviate the effects of transplant in vegetables has also been recognized. However, the scarce data available on the use of Azospirillum to improve lettuce growth before and after transplant under saline conditions prompted us to focus our research on this topic. Early germination and seedling settlement of seeds exposed to 0 and 40 mol m(-3) NaCl were clearly improved by Azospirillum inoculation. At 0 mol m(-3) NaCl, plant establishment, leaf mass and root mass parameters before transplant were significantly higher in inoculated plants than in non-inoculated controls. At harvest, leaf fresh weight, ascorbic acid content and plant survival to transplant were also significantly higher in Azospirillum-inoculated plants grown at 0 mol m(-3) NaCl. In addition to these effects, leaf dry weight, area and chlorophyll content were also increased by Azospirillum inoculation when plants were grown at 40 mol m(-3) NaCl. Azospirillum-inoculated lettuce seeds yield a higher number of transplanted plants with superior quality than non-inoculated controls grown at 0 or at 40 mol m(-3) NaCl. Copyright © 2012 Society of Chemical Industry.

  15. 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.

  16. [Detection of putative polysaccharide biosynthesis genes in Azospirillum brasilense strains from serogroups I and II].

    Science.gov (United States)

    Petrova, L P; Prilipov, A G; Katsy, E I

    2017-01-01

    It is known that in Azospirillum brasilense strains Sp245 and SR75 included in serogroup I, the repeat units of their O-polysaccharides consist of five residues of D-rhamnose, and in strain SR15, of four; and the heteropolymeric O-polysaccharide of A. brasilense type strain Sp7 from serogroup II contains not less than five types of repeat units. In the present work, a complex of nondegenerate primers to the genes of A. brasilense Sp245 plasmids AZOBR_p6, AZOBR_p3, and AZOBR_p2, which encode putative enzymes for the biosynthesis of core oligosaccharide and O-polysaccharide of lipopolysaccharide, capsular polysaccharides, and exopolysaccharides, was proposed. By using the designed primers, products of the expected sizes were synthesized in polymerase chain reactions on genomic DNA of A. brasilense Sp245, SR75, SR15, and Sp7 in 36, 29, 23, and 12 cases, respectively. As a result of sequencing of a number of amplicons, a high (86–99%) level of identity of the corresponding putative polysaccharide biosynthesis genes in three A. brasilense strains from serogroup I was detected. In a blotting-hybridization reaction with the biotin-labeled DNA of the A. brasilense gene AZOBR_p60122 coding for putative permease of the ABC transporter of polysaccharides, localization of the homologous gene in ~120-MDa plasmids of the bacteria A. brasilense SR15 and SR75 was revealed.

  17. 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 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.

  18. 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.

  19. Labeled Azospirillum brasilense wild type and excretion-ammonium strains in association with barley roots.

    Science.gov (United States)

    Santos, Adrian Richard Schenberger; Etto, Rafael Mazer; Furmam, Rafaela Wiegand; Freitas, Denis Leandro de; Santos, Karina Freire d'Eça Nogueira; Souza, Emanuel Maltempi de; Pedrosa, Fábio de Oliveira; Ayub, Ricardo Antônio; Steffens, Maria Berenice Reynaud; Galvão, Carolina Weigert

    2017-09-01

    Soil bacteria colonization in plants is a complex process, which involves interaction between many bacterial characters and plant responses. In this work, we labeled Azospirillum brasilense FP2 (wild type) and HM053 (excretion-ammonium) strains by insertion of the reporter gene gusA-kanamycin into the dinitrogenase reductase coding gene, nifH, and evaluated bacteria colonization in barley (Hordeum vulgare). In addition, we determined inoculation effect based on growth promotion parameters. We report an uncommon endophytic behavior of A. brasilense Sp7 derivative inside the root hair cells of barley and highlight the promising use of A. brasilense HM053 as plant growth-promoting bacterium. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

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

    International Nuclear Information System (INIS)

    Obando Castellanos, Dolly Melissa; Burgos Zabala, Ludy Beatriz; Rivera Botia, Diego Mauricio; Rubiano Garrido, Maria Fernanda; Divan Baldini, Vera Lucia; Bonilla Buitrago, Ruth Rebeca

    2010-01-01

    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)).

  1. 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.

  2. Phase Variation and Genomic Architecture Changes in Azospirillum

    Science.gov (United States)

    Vial, Ludovic; Lavire, Céline; Mavingui, Patrick; Blaha, Didier; Haurat, Jacqueline; Moënne-Loccoz, Yvan; Bally, René; Wisniewski-Dyé, Florence

    2006-01-01

    The plant growth-promoting rhizobacterium Azospirillum lipoferum 4B generates in vitro at high frequency a stable nonswimming phase variant designated 4VI, which is distinguishable from the wild type by the differential absorption of dyes. The frequency of variants generated by a recA mutant of A. lipoferum 4B was increased up to 10-fold. The pleiotropic modifications characteristic of the phase variant are well documented, but the molecular processes involved are unknown. Here, the objective was to assess whether genomic rearrangements take place during phase variation of strain 4B. The random amplified polymorphic DNA (RAPD) profiles of strains 4B and 4VI differed. RAPD fragments observed only with the wild type were cloned, and three cosmids carrying the corresponding fragments were isolated. The three cosmids hybridized with a 750-kb plasmid and pulse-field gel electrophoresis analysis revealed that this replicon was missing in the 4VI genome. The same rearrangements took place during phase variation of 4BrecA. Large-scale genomic rearrangements during phase variation were demonstrated for two additional strains. In Azospirillum brasilense WN1, generation of stable variants was correlated with the disappearance of a replicon of 260 kb. For Azospirillum irakense KBC1, the variant was not stable and coincided with the formation of a new replicon, whereas the revertant recovered the parental genomic architecture. This study shows large-scale genomic rearrangements in Azospirillum strains and correlates them with phase variation. PMID:16855225

  3. [Ligninolytic Activity of Bacteria of the Genera Azospirillum and Niveispirillum].

    Science.gov (United States)

    Kupryashina, M A; Petrov, S V; Ponomareva, E G; Nikitina, V E

    2015-01-01

    Capacity of associative soil bacteria of the genera Azospirillum and Niveispirillum for degradation of lignin model compounds was demonstrated. Lignin and Mn-peroxidases were detected in the culture liquid of the type strains of these genera. The data on involvement of nonspecific bacterial peroxidases in lignin degradation were obtained.

  4. Polymers selection for a liquid inoculant of Azospirillum brasilense ...

    African Journals Online (AJOL)

    In this study, we used a method of accelerated degradation to select a polymer and a concentration to maintain cell stability of a liquid inoculant based on the strain C16 Azospirillum brasilense. A screening at 45°C was made to compare the protectant effect of five polymers on the viability of the strain (p/v): carrageenan ...

  5. Polymers selection for a liquid inoculant of Azospirillum brasilense ...

    African Journals Online (AJOL)

    Sandra Lucia Cortes Patiño

    2015-08-19

    Aug 19, 2015 ... In this study, we used a method of accelerated degradation to select a polymer and a concentration to maintain .... Table 1. Previous reports of the selected polymers for the screening with strain C16 Azospirillum brasilense. Polymer ..... Vodyanoy VJ (2009). Preservation of bacteria in natural polymers. J.

  6. 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. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  7. 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.

  8. [Characterization of the lipopolysaccharides of serogroup II Azospirillum].

    Science.gov (United States)

    Sigida, E N; Fedonenko, Iu P; Zdorovenko, É L; Butygin, G L; Konnova, S A; Ignatov, V V

    2014-01-01

    Lipopolysaccharides of six Azospirillum strains (A. brasilense SR50, SR80, SR88, SR109, SR111, SR115, and A. lipoferum SR 42) isolated from the rhizosphere of cereal plants of Saratov oblast, Russia and assigned to serogroup II by serological analysis were studied. In the lipid A fatty acid composition, the lipopolysaccharides under study were similar to those of other Azospirillum strains and were characterized by predominance of 3-hydroxytetradecanoic, 3-hydroxyhexadecanoic, and octadecenoic acids. Monosaccharide analysis of the O-specific polysaccharides (including determination of the absolute configurations, methylation analysis, and one- and two-dimensional NMR spectroscopy) revealed the presence of two types of repeating units in varying ratios. High degree of serological similarity between the strains under study was shown to result from the presence of repeating units with identical structure in their O antigens.

  9. Azospirillum brasilense, a Beneficial Soil Bacterium: Isolation and Cultivation.

    Science.gov (United States)

    Alexandre, Gladys

    2017-11-09

    Bacteria of the genus Azospirillum comprise 15 species to date, with A. brasilense the best studied species in the genus. Azospirillum are soil bacteria able to promote the growth of plants from 113 species spanning 35 botanical families. These non-pathogenic and beneficial bacteria are ubiquitous in soils and inhabit the roots of diverse plants. These bacteria are microaerophilic, able to fix nitrogen under free-living conditions, motile, and able to navigate in gradients of various chemicals, including oxygen. These physiological traits are used to isolate these soil bacteria from soil and plant root samples, providing isolates that can be used for studying microbial physiology and plant growth promotion. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

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

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    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.

  11. 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.

  12. Caracterización de cepas nativas de Azospirillum spp. y su efecto en el desarrollo de Oryza sativa L. “arroz” en Lambayeque

    Directory of Open Access Journals (Sweden)

    Franklin García

    2010-01-01

    Full Text Available La presente investigación se realizó para caracterizar y determinar el efecto de cepas nativas de Azospirillum spp. en el desarrollo de Oryza sativa L “arroz”, como una alternativa para la disminución de fertilizantes químicos. Las bacterias se aislaron de raíces de arroz en Lambayeque. Fragmentos de raíces previamente desinfectadas se sembraron en medio Nfb semisólido, donde las bacterias fijadoras de nitrógeno se reconocieron por una película blanquecina bajo la superficie y el viraje del verde al azul. El género Azospirillum se identificó en medio agar rojo de Congo, obteniéndose 96 cepas con una producción de 2.69 a 38.02 ppm de ácido indolacético y 7.95 a 29.09 ppm de nitrógeno fijado. Las cuatro cepas con los mayores valores se inocularon independientemente así como en combinación con 50 y 100 % de úrea, en arroz INIA508-Tinajones. Se utilizó un diseño experimental completamente aleatorio, incluyendo testigos 50 y 100 % de úrea y testigo absoluto, Todas las cepas nativas incrementaron la altura y materia seca de la parte aérea y raíces, con índices de efectividad de hasta 21.77, 102.06 y 126.11% en relación al testigo absoluto. Azospirillum sp. GM-86 seleccionado por el mayor valor de ácido indolacético, alcanzó el mayor índice de efectividad en altura y biomasa seca de raíz. La aplicación de 50 % de úrea con Azospirillum spp. incrementó los índices de efectividad. Se demostró el potencial de cepas nativas de Azospirillum spp. para incrementar el desarrollo de arroz, así como la posibilidad de utilizarlas asociadas con dosis mínimas de úrea.

  13. 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. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  14. Phenotypic and molecular characterization of native Azospirillum strains from rice fields to improve crop productivity.

    Science.gov (United States)

    Sahoo, Ranjan K; Ansari, Mohammad W; Pradhan, Madhusmita; Dangar, Tushar K; Mohanty, Santanu; Tuteja, Narendra

    2014-07-01

    Beneficial microorganisms have been considered as an important tool for crop improvement. Native isolates of Azospirillum spp. were obtained from the rhizospheres of different rice fields. Phenotypic, biochemical and molecular characterizations of these isolates led to the identification of six efficient strain of Azospirillum. PCR amplification of the nif genes (nifH, nifD and nifK) and protein profile of Azospirillum strains revealed inter-generic and inter-specific diversity among the strains. In vitro nitrogen fixation performance and the plant growth promotion activities, viz. siderophore, HCN, salicylic acid, IAA, GA, zeatin, ABA, NH3, phosphorus metabolism, ACC deaminase and iron tolerance were found to vary among the Azospirillum strains. The effect of Azospirillum formulations on growth of rice var. Khandagiri under field condition was evaluated, which revealed that the native formulation of Azospirillum of CRRI field (As6) was most effective to elevate endogenous nutrient content, and improved growth and better yield are the result. The 16S rRNA sequence revealed novelty of native Azospirillum lipoferum (As6) (JQ796078) in the NCBI database.

  15. 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).

  16. 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

  17. Azospirillum irakense Produces a Novel Type of Pectate Lyase

    OpenAIRE

    Bekri, My Ali; Desair, Jos; Keijers, Veerle; Proost, Paul; Searle-van Leeuwen, Marjo; Vanderleyden, Jos; vande Broek, Ann

    1999-01-01

    The pelA gene from the N2-fixing plant-associated bacterium Azospirillum irakense, encoding a pectate lyase, was isolated by heterologous expression in Escherichia coli. Nucleotide sequence analysis of the region containing pelA indicated an open reading frame of 1,296 bp, coding for a preprotein of 432 amino acids with a typical amino-terminal signal peptide of 24 amino acids. N-terminal amino acid sequencing confirmed the processing of the protein in E. coli at the signal peptidase cleavage...

  18. Screening on Gibberellic Acid Producing Activity of Azospirillum Isolates

    International Nuclear Information System (INIS)

    Shun Lai Ei; Khin Mya Lwin; Myo Myint

    2010-12-01

    Six strains of Azopirillum spp were isolated from rice, sugarcane, corn, maize, sunflower and pepper roots and screened the gibberellic acid productivity. Only three strains of Azospirillum species showed the activity and were indentified by cultural, biochemical and drug sensitivity patterns. Among them,one strain isolated from rice root can produce microbial gibberellic acid. It showed greenish yellow colour in chromatogram under UV absorption. This screening method was studied from 1 to 14 days incubation. Qualitative measurement of GA productivity was determined by thin layer chromatography.

  19. The Effects of Carboxin-thiram on Associative Relationships between Azospirillum Species and Wheat (Chamran Cultivar

    Directory of Open Access Journals (Sweden)

    F. rejali

    2017-03-01

    Full Text Available Introduction: Biofertilizers have been identified as alternative to chemical fertilizers to increase soil fertility and crop production in sustainable farming systems. One of the most useful kind of biofertilizers include plant growth promoting rhizobacteria (PGPR. Azospirillum is an associative rhizobacteria which can be very useful for plants such as wheat. It can help plant by fixing nitrogen through biological way, causing root development, plant strength improvement in primary phases, causing germination percent increment, improving plant tolerance in stress situations (drought, salinity, soil compaction and pathogens, secreting plant promoting hormones like cytokinin, Oxin and finally yield increment will be observable. Modern agriculture largely relies on the extensive application of agrochemicals, including inorganic fertilizers and pesticides. Although pesticides are important, their effects on nontarget organisms are of great concern because this poses a risk to the entire ecological system. The fungicides may also adversely affect the soil microflora, especially the types of microorganisms that can applied to seeds as bacterial inoculants. Considering useful effects of plant growth promoting rhizobacteria especially Azospirillum on Wheat, this study was done in order to survey interaction effects between fungicide and available biofertilizers in Iran market. Materials and Methods: Effect of carboxin tiram in 2 levels (applied, non-applied as fungicide, on efficacy of wheat plant (Chamran Cultivar and final crop yields under association conditions with 5 Azospirillum species (A.brasilense, A.lipoferum, A.halopraeferense, A.irakense, A.sp using powdery and liquid formulation were studied in a greenhouse test for four months in Soil and Water Research Institute.At first some properties of used soil, including soil texture, pH, EC,organic carbon and available soil K, P, Fe, Zn, Mn and Cu were measured by laboratory methods.Nutrient Broth

  20. 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.

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

    Science.gov (United States)

    Wisniewski-Dyé, Florence; Borziak, Kirill; Khalsa-Moyers, Gurusahai; Alexandre, Gladys; Sukharnikov, Leonid O; Wuichet, Kristin; Hurst, Gregory B; McDonald, W Hayes; Robertson, Jon S; Barbe, Valérie; Calteau, Alexandra; Rouy, Zoé; Mangenot, Sophie; Prigent-Combaret, Claire; Normand, Philippe; Boyer, Mickaël; Siguier, Patricia; Dessaux, Yves; Elmerich, Claudine; Condemine, Guy; Krishnen, Ganisan; Kennedy, Ivan; Paterson, Andrew H; González, Victor; Mavingui, Patrick; Zhulin, Igor B

    2011-12-01

    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.

  2. 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.

  3. Involvement of the Reserve Material Poly-β-Hydroxybutyrate in Azospirillum brasilense Stress Endurance and Root Colonization

    Science.gov (United States)

    Kadouri, Daniel; Jurkevitch, Edouard; Okon, Yaacov

    2003-01-01

    When grown under suboptimal conditions, rhizobacteria of the genus Azospirillum produce high levels of poly-β-hydroxybutyrate (PHB). Azospirillum brasilense strain Sp7 and a phbC (PHB synthase) mutant strain in which PHB production is impaired were evaluated for metabolic versatility, for the ability to endure various stress conditions, for survival in soil inoculants, and for the potential to promote plant growth. The carbon source utilization data were similar for the wild-type and mutant strains, but the generation time of the wild-type strain was shorter than that of the mutant strain with all carbon sources tested. The ability of the wild type to endure UV irradiation, heat, osmotic pressure, osmotic shock, and desiccation and to grow in the presence of hydrogen peroxide was greater than that of the mutant strain. The motility and cell aggregation of the mutant strain were greater than the motility and cell aggregation of the wild type. However, the wild type exhibited greater chemotactic responses towards attractants than the mutant strain exhibited. The wild-type strain exhibited better survival than the mutant strain in carrier materials used for soil inoculants, but no difference in the ability to promote plant growth was detected between the strains. In soil, the two strains colonized roots to the same extent. It appears that synthesis and utilization of PHB as a carbon and energy source by A. brasilense under stress conditions favor establishment of this bacterium and its survival in competitive environments. However, in A. brasilense, PHB production does not seem to provide an advantage in root colonization under the conditions tested. PMID:12788722

  4. Azospirillum brasilense and Azospirillum lipoferum Hydrolyze Conjugates of GA20 and Metabolize the Resultant Aglycones to GA1 in Seedlings of Rice Dwarf Mutants1

    Science.gov (United States)

    Cassán, Fabricio; Bottini, Rubén; Schneider, Gernot; Piccoli, Patricia

    2001-01-01

    Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins (GAs). In this work, Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice (Oryza sativa) mutants, dy and dx, when the inoculated seedlings were supplied with [17,17-2H2]GA20-glucosyl ester or [17,17- 2H2]GA20-glucosyl ether. Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17-2H2]GA20 and its subsequent 3β-hydroxylation to [17,17-2H2]GA1 by the microorganism for the dy mutant, and by both the rice plant and microorganism for the dx mutant. PMID:11299384

  5. 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. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  6. 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.

  7. A rapid and simple PCR method for identifying isolates of the genus Azospirillum within populations of rhizosphere bacteria.

    Science.gov (United States)

    Shime-Hattori, A; Kobayashi, S; Ikeda, S; Asano, R; Shime, H; Shinano, T

    2011-10-01

    To develop a rapid and simple genus-specific polymerase chain reaction (PCR) method for detecting and identifying isolates of the genus Azospirillum which is well-recognized as plant growth-promoting rhizobacterium. Nine pairs of PCR primers were designed based on the Azospirillum 16S rRNA, ipdC, nifA and nifH genes to assess their genus specificity by testing against 12 Azospirillum (from seven species) and 15 non-Azospirillum reference strains, as compared with the fAZO/rAZO pair reported by Baudoin et al. (J Appl Microbiol, 108, 2010, 25). Among the primer pairs assessed, the Az16S-A pair designed on the 16S rRNA gene sequence showed the highest genus specificity: it successfully yielded a single amplicon of the expected size in all the 12 Azospirillum strains and for a close relative, Rhodocista centenaria. The PCR with the Az16S-A primers generated a detectable amount of the amplicon from ≥10³ CFU ml⁻¹ of Azospirillum cell suspensions even in the presence of contaminants and accurately discriminated Azospirillum and non-Azospirillum species in both 35 Azospirillum-like and 70 unknown isolates from plant roots and rhizosphere soils. We developed a rapid and simple PCR method for detecting and identifying Azospirillum isolates within populations of rhizosphere bacteria. The method developed would serve as a useful tool for isolating a variety of indigenous Azospirillum bacteria from agricultural samples. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

  8. Structural effects of the Azospirillum lipopolysaccharides in cell suspensions.

    Science.gov (United States)

    Matora, L Y; Serebrennikova, O B; Shchyogolev, S Y

    2001-01-01

    The structural influence of Azospirillum lipopolysaccharides (LPS) and lipopolysaccharide-protein complexes (LPPC) on carrot, erythrocyte, and bacterial cell suspensions was explored. The structural potentialities of O-specific polysaccharide fragments of LPS and protein fractions of LPPC were also evaluated. An ability to induce the formation of three kinds of structures in the cell suspensions was revealed depending on the chemical composition of the preparations used. The first and the second ones were connected with effects of cell aggregation (a relatively fast process) and agglutination (a relatively slow process). The third one resulted in phase separation of erythrocyte suspensions (a medium-speed process), with segregating the cells to a separate homogeneous liquid phase.

  9. 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.

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

    Directory of Open Access Journals (Sweden)

    Dolly Melissa Obando Castellanos

    2010-09-01

    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.

  11. 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.

  12. Irrigated wheat subjected to inoculation with Azospirillum brasilense and nitrogen doses as top-dressing

    Directory of Open Access Journals (Sweden)

    Cleiton J. Alves

    Full Text Available ABSTRACT The use of Azospirillum brasilense in the wheat crop still presents contradictory results; thus, it is necessary to identify ideal conditions to obtain satisfactory results. The objective of this study was to investigate the interaction between Azospirillum brasilense and nitrogen doses in a wheat cultivar, conducted with irrigation in the Cerrado region of Mato Grosso do Sul. The experimental design was randomized blocks with a 4 x 2 factorial scheme, four nitrogen doses (0, 40, 80 and 120 kg ha-1 applied as top-dressing, associated or not with inoculation of wheat seeds with Azospirillum brasilense. The results show that there was no interaction between N and inoculation. The isolated effect of Azospirillum brasilense promotes an increase in plant height and number of grains per spike. Nitrogen doses promotes significant increases in leaf N content, plant height, number of grains per spike, number of spikes per square meter and grain yield. The conditions under which the experiment was conducted favored the development of the crop, not interfering with grain yield due the inoculation with Azospirillum brasilense.

  13. 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.

  14. Directed mutagenesis affects recombination in Azospirillum brasilense nif genes

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    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

  15. 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. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  16. 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. Copyright © 2010 Elsevier GmbH. All rights reserved.

  17. 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.

  18. Energy Taxis Is the Dominant Behavior in Azospirillum brasilense

    Science.gov (United States)

    Alexandre, Gladys; Greer, Suzanne E.; Zhulin, Igor B.

    2000-01-01

    Energy taxis encompasses aerotaxis, phototaxis, redox taxis, taxis to alternative electron acceptors, and chemotaxis to oxidizable substrates. The signal for this type of behavior is originated within the electron transport system. Energy taxis was demonstrated, as a part of an overall behavior, in several microbial species, but it did not appear as the dominant determinant in any of them. In this study, we show that most behavioral responses proceed through this mechanism in the alpha-proteobacterium Azospirillum brasilense. First, chemotaxis to most chemoeffectors typical of the azospirilla habitat was found to be metabolism dependent and required a functional electron transport system. Second, other energy-related responses, such as aerotaxis, redox taxis, and taxis to alternative electron acceptors, were found in A. brasilense. Finally, a mutant lacking a cytochrome c oxidase of the cbb3 type was affected in chemotaxis, redox taxis, and aerotaxis. Altogether, the results indicate that behavioral responses to most stimuli in A. brasilense are triggered by changes in the electron transport system. PMID:11029423

  19. 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.

  20. Rapid detection and identification of the free-living nitrogen fixing genus Azospirillum by 16S rRNA-gene-targeted genus-specific primers.

    Science.gov (United States)

    Lin, Shih-Yao; Shen, Fo-Ting; Young, Chiu-Chung

    2011-05-01

    The modern agricultural practice utilizing plant growth promoting rhizobacteria (PGPR) has brought great benefits in the promotion of crop growth. Among PGPR, Azospirillum is considered as an important genus which is not only closely-associated with plants but also shows potential in the degradation of organic contaminants. However, lack of media for selective isolation or techniques for specific detection or identification limit the exploration of these rhizobacteria. This motivated us to design a genus-specific oligonucleotide primer pair which could assist in rapid detection of species of the genus Azospirillum by means of PCR-specific amplification. The sensitivity and specificity of the newly designed primer pair Azo494-F/Azo756-R were tested against 12 Azospirillum type strains and other closely-related genera. The Azospirillum-specific 16S rRNA gene fragment (263 bp) was successfully amplified for all the reference Azospirillum species with the designed primer pair. No amplification was noted for closely-related species from other genera. The genus specificity was validated with 18 strains including environmental isolates. Interestingly, two strains assigned earlier as Azospirillum amazonense (DSM 2787(T)) and Azospirillum irakense (DSM 11586(T)) failed to produce an Azospirillum-specific fragment with this primer pair. Further phylogenetic analysis of these two isolates based on 16S rRNA gene sequences shows that these two strains might belong to other genera rather than Azospirillum. Preliminary screening of isolates and soil samples with the Azospirillum-specific primers was successful in terms of the rapid detection of Azospirillum isolates. By using real-time PCR analysis the minimum limit of Azospirillum detection was 10(2) CFU g(-1) in the seeded soil sample. The newly designed primers can be used to study the diversity of Azospirillum in ecosystems and aid in the exploration of novel species.

  1. /sup 15/N/sub 2/ incorporation and acetylene reduction by azospirillum isolated from rice roots and soils

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, D.N.; Charyulu, P.B.B.; Rajaramamohan Rao, V. (Central Rice Research Inst., Cuttack (India). Dept. of Soil Microbiology)

    1981-01-01

    Nitrogen fixation by strains of Azospirillum isolated from several rice soils and rice cultivars was investigated by /sup 15/N/sub 2/ incorporation and C/sub 2/H/sub 2/ reduction. C/sub 2/H/sub 2/ reducing ability markedly varied among the strains obtained from soils differing widely in their physico-chemical properties. Large variations in /sup 15/N/sub 2/ incorporation by Azospirillum isolated from the roots of several rice cultivars were also noticed. The present study reveals that rice cultivars harbour Azospirillum with differential N/sub 2/-fixing ability and that plant genotype is of importance for optimal associations.

  2. INOKULASI Azospirillium sp DARI LAHAN KERING MADURA TERHADAP PERTUMBUHAN TANAMAN JAGUNG

    Directory of Open Access Journals (Sweden)

    Ach. Khoirul Ikhwan

    2015-12-01

    Full Text Available Penelitian ini bertujuan untuk memperoleh isolat bakteri Azospirillium sp dari Madura, serta mengkaji kehandalannya dalam menggantikan pupuk N sintetik. Samel tanah diambil dari Kecamatan Galis, Geger dan Tanahmerah, isolasi dilakukan dengan menggunakan media semi solid Nfb, selanjutnya diuji kehandalannya berdasarkan pengaruhnya terhadap pertumbuhan tanaman jagung. Diperoleh 1 isolat yang terbaik yaitu isolat yang diisolasi dari rhizosper tanaman Graminae di Kecamatan Galis, namun demikian berdasarkan pertumbuhan tanaman jagung belum bisa menggantikan pupun N sintetik.Kata kunci : Azospirillum sp, jagung, nitrogen, isolat madura

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

    Science.gov (United States)

    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. PMID:16534964

  4. Maize growth in response to Azospirillum brasilense, Rhizobium tropici, molybdenum and nitrogen

    Directory of Open Access Journals (Sweden)

    Angelita A. C. Picazevicz

    Full Text Available ABSTRACT The objective of this research was to evaluate the effect of Azospirillum brasilense, Rhizobium tropici, nitrogen (N and molybdenum (Mo fertilization on maize growth. The experiment was carried out in a greenhouse from October to November 2015, in a completely randomized design, in 2 x 2 x 2 x 5 factorial scheme, with 5 replicates, corresponding to the absence and presence of Azospirillum brasilense, Rhizobium tropici, N (30 kg ha-1 and five Mo doses (0, 7.5, 15.0, 22.5 and 30.0 g ha-1. The analyzed variables were: plant height, basal stem diameter, dry biomass of shoots, roots, total and N accumulated in the shoots. There was double or triple interaction between N fertilization, Azospirillum brasilense and Rhizobium tropici for the evaluated variables. However, isolated and/or combined effect of Mo was not observed. Seed inoculation with Azospirillum brasilense as well as their co-inoculation with Rhizobium tropici in the absence of N fertilization was efficient to increase plant growth. Soil N fertilization at sowing was less efficient in promoting plant growth than when it was combined with seed inoculation with Rhizobium tropici.

  5. 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

  6. Granulomatous infection of the hand and wrist due to Azospirillum spp.

    Science.gov (United States)

    Serelis, John; Papaparaskevas, Joseph; Stathi, Angeliki; Sawides, Alexander L; Karagouni, Amalia D; Tsakris, Athanassios; Pangalis, Anastasia

    2013-08-01

    We report a case of Azospirillum infection manifestating as granulomatous tenosynovitis of the right hand, in an immunocompetent middle-aged female. We highlight the unusual source of the infection, the diagnostic workup, as well as the treatment approach. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Genomic insights into metabolic versatility of a lithotrophic sulfur-oxidizing diazotrophic Alphaproteobacterium Azospirillum thiophilum.

    Science.gov (United States)

    Orlova, Maria V; Tarlachkov, Sergey V; Dubinina, Galina A; Belousova, Elena V; Tutukina, Maria N; Grabovich, Margarita Y

    2016-12-01

    Diazotrophic Alphaproteobacteria of the genus Azospirillum are usually organotrophs, although some strains of Azospirillum lipoferum are capable of hydrogen-dependent autotrophic growth. Azospirillum thiophilum strain was isolated from a mineral sulfide spring, a biotope highly unusual for azospirilla. Here, the metabolic pathways utilized by A. thiophilum were revealed based on comprehensive analysis of its genomic organization, together with physiological and biochemical approaches. The A. thiophilum genome contained all the genes encoding the enzymes of carbon metabolism via glycolysis, tricarboxylic acid cycle and glyoxylate cycle. Genes for a complete set of enzymes responsible for autotrophic growth, with an active Calvin-Benson-Bassham cycle, were also revealed, and activity of the key enzymes was determined. Microaerobic chemolithoautotrophic growth of A. thiophilum was detected in the presence of thiosulfate and molecular hydrogen, being in line with the discovery of the genes encoding the two enzymes involved in dissimilatory thiosulfate oxidation, the Sox-complex and thiosulfate dehydrogenase and Ni-Fe hydrogenases. Azospirillum thiophilum utilizes methanol and formate, producing CO 2 that can further be metabolized via the Calvin cycle. Finally, it is capable of anaerobic respiration, using tetrathionate as a terminal electron acceptor. Such metabolic versatility is of great importance for adaptation of A. thiophilum to constantly changing physicochemical environment. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Development and standardization of cyst based liquid formulation of Azospirillum bioinoculant.

    Science.gov (United States)

    Vendan, Regupathy Thamizh; Thangaraju, Muthusamy

    2007-06-01

    Azospirillum bioinoculant is well known for its high nitrogen fixing and plant growth promoting characters. The carrier based bioinoculants generally suffer from shorter shelf life, poor quality, high contamination and low field performance. Therefore, it is necessary to develop alternative new formulation of inoculants where cyst based inoculants can play significant role. The cyst based liquid formulation was developed by inoculating Azospirillum into the cyst inducing minimal salts medium (MSM). One hundred per cent conversion of vegetative cells into cyst cells was noticed in 96 h. The survival of cyst cells in the MSM was observed up to one year and two months and interestingly, the population level of 10(8) was maintained till the final observation. The cyst cells of Azospirillum accumulated poly-beta-hydroxybutyrate (PHB) granules and exhibited desiccation tolerance up to 20 days and temperature tolerance up to 40 degrees C. Thus the cyst based liquid formulation has twin advantage of longer shelf life and tolerance to harmful environmental conditions. Regeneration of cyst cells into vegetative cells in different media viz., tap water, sterile water, rice gruel and nutrient broth was studied. The changes started within 3 h and complete return of vegetative cells was observed at 24 h. Although all the media tested favoured regeneration, comparatively quicker regeneration was observed in nutrient broth and followed by rice gruel. Thus, cyst based liquid formulation of Azospirillum has all the survival advantages and can be used as a potential bioinoculant.

  9. Evaluation of effect of inoculation of Azospirillum on the yield of ...

    African Journals Online (AJOL)

    Inoculation of foxtail millet (variety Lepakshi) with three strains of Azospirillum lipoferum either alone or in combination with nitrogen fertilizer (40 kg N ha-1) increased the plant height, dry weight of shoot and root, and total N content of shoot, root and grain. The grain yield of the inoculated plants was significantly higher ...

  10. Economic analysis of corn inoculated with Azospirillum brasilense associated with nitrogen sources and doses

    Directory of Open Access Journals (Sweden)

    Fernando Shintate Galindo

    2017-08-01

    Full Text Available Azospirillum brasilense is a bacterium known for its biological nitrogen fixation (BNF in corn crops. However, there is a lack of comprehensive research defining how much mineral N should be applied to maximize the efficiency of BNF and attain high, economically sustainable yields. Moreover, it would be interesting to investigate whether adding urea with NBPT urease inhibitor might increase BNF in grasses. Therefore, the aim of this study was to determine the effect of inoculation with Azospirillum brasilense associated with N sources and doses in a Cerrado biome soil by evaluating the grain yield of irrigated corn in economic terms. The experiment was conducted in Selvíria, MS, Brazil under a no-till system on a Latossolo Vermelho distrófico (Oxisol. The experiment was set up as a randomized block design with four replications in a 2 × 5 × 2 factorial arrangement consisting of two sources of N (urea and urea with NBPT urease enzyme inhibitor and five N doses applied as top-dressing (0, 50, 100, 150, and 200 kg ha-1, with and without the inoculation of seeds with A. brasilense. Inoculation with Azospirillum brasilense makes corn growth much more profitable, irrespective of the dose and source of N. Addition of 200 kg ha-1 N in the form of conventional urea coupled with inoculation with Azospirillum brasilense increases grain yield; however, the highest economic return is obtained with N applied at 100 kg ha-1 with conventional urea and inoculation.

  11. [Biosynthesis of silver nanoparticles with the participation of extracellular Mn-dependent peroxidase from Azospirillum].

    Science.gov (United States)

    Kupryashina, M A; Vetchinkina, E P; Nikitina, V E

    2016-01-01

    The accumulation of nanoparticles of colloidal silver with spherical shape in culture liquid of Azospirillum brasilense has been shown by transmission electron microscopy. Bacterial extracellular Mn-peroxidases were found to participate in silver reduction from silver nitrate with the formation of nanoparticles. A mechanism of extracellular biosynthesis of silver nanoparticles by A. brasilense bacteria was proposed

  12. First Azospirillum genome from aquatic environments: Whole-genome sequence of Azospirillum thiophilum BV-S(T), a novel diazotroph harboring a capacity of sulfur-chemolithotrophy from a sulfide spring.

    Science.gov (United States)

    Kwak, Yunyoung; Shin, Jae-Ho

    2016-02-01

    Azospirillum thiophilum BV-S(T), isolated from a sulfide spring, is a novel nitrogen-fixing bacterium harboring sulfur-lithotrophy. In order to identify genetic characteristics with habitat- and metabolic features contrasting to those from terrestrial Azospirillum species, we present here the genome sequence of a novel species A. thiophilum BV-S(T), with a significance of first genome report in the aquatic Azospirillum species. The genome of strain BV-S(T) is comprised of 7.6Mb chromosome with a GC content of 68.2%. This information will contribute to expand understandings of sulfur-oxidizer microbes that preserve inherencies as a diazotroph, and further it will provide insights into genome plasticity of the genus Azospirillum for niche specific adaptations. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Azospirillum irakense Produces a Novel Type of Pectate Lyase

    Science.gov (United States)

    Bekri, My Ali; Desair, Jos; Keijers, Veerle; Proost, Paul; Searle-van Leeuwen, Marjo; Vanderleyden, Jos; vande Broek, Ann

    1999-01-01

    The pelA gene from the N2-fixing plant-associated bacterium Azospirillum irakense, encoding a pectate lyase, was isolated by heterologous expression in Escherichia coli. Nucleotide sequence analysis of the region containing pelA indicated an open reading frame of 1,296 bp, coding for a preprotein of 432 amino acids with a typical amino-terminal signal peptide of 24 amino acids. N-terminal amino acid sequencing confirmed the processing of the protein in E. coli at the signal peptidase cleavage site predicted by nucleotide sequence analysis. Analysis of the amino acid sequence of PelA revealed no homology to other known pectinases, indicating that PelA belongs to a new pectate lyase family. PelA macerates potato tuber tissue, has an alkaline pH optimum, and requires Ca2+ for its activity. Of several divalent cations tested, none could substitute for Ca2+. Methyl-esterified pectin (with a degree of esterification up to 93%) and polygalacturonate can be used as substrates. Characterization of the degradation products formed upon incubation with polygalacturonate indicated that PelA is an endo-pectate lyase generating unsaturated digalacturonide as the major end product. Regulation of pelA expression was studied by means of a translational pelA-gusA fusion. Transcription of this fusion is low under all growth conditions tested and is dependent on the growth phase. In addition, pelA expression was found to be induced by pectin. An A. irakense pelA::Tn5 mutant still displayed pectate lyase activity, suggesting the presence of multiple pectate lyase genes in A. irakense. PMID:10198006

  14. Azospirillum irakense produces a novel type of pectate lyase.

    Science.gov (United States)

    Bekri, M A; Desair, J; Keijers, V; Proost, P; Searle-van Leeuwen, M; Vanderleyden, J; Vande Broek, A

    1999-04-01

    The pelA gene from the N2-fixing plant-associated bacterium Azospirillum irakense, encoding a pectate lyase, was isolated by heterologous expression in Escherichia coli. Nucleotide sequence analysis of the region containing pelA indicated an open reading frame of 1,296 bp, coding for a preprotein of 432 amino acids with a typical amino-terminal signal peptide of 24 amino acids. N-terminal amino acid sequencing confirmed the processing of the protein in E. coli at the signal peptidase cleavage site predicted by nucleotide sequence analysis. Analysis of the amino acid sequence of PelA revealed no homology to other known pectinases, indicating that PelA belongs to a new pectate lyase family. PelA macerates potato tuber tissue, has an alkaline pH optimum, and requires Ca2+ for its activity. Of several divalent cations tested, none could substitute for Ca2+. Methyl-esterified pectin (with a degree of esterification up to 93%) and polygalacturonate can be used as substrates. Characterization of the degradation products formed upon incubation with polygalacturonate indicated that PelA is an endo-pectate lyase generating unsaturated digalacturonide as the major end product. Regulation of pelA expression was studied by means of a translational pelA-gusA fusion. Transcription of this fusion is low under all growth conditions tested and is dependent on the growth phase. In addition, pelA expression was found to be induced by pectin. An A. irakense pelA::Tn5 mutant still displayed pectate lyase activity, suggesting the presence of multiple pectate lyase genes in A. irakense.

  15. 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. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  16. Low endotoxic activity of lipopolysaccharides isolated from Bradyrhizobium, Mesorhizobium, and Azospirillum strains.

    Science.gov (United States)

    Komaniecka, Iwona; Zdzisinska, Barbara; Kandefer-Szerszen, Martyna; Choma, Adam

    2010-12-01

    The endotoxic activities of lipopolysaccharides (LPS) isolated from different strains of rhizobia and rhizobacteria (Bradyrhizobium, Mesorhizobium, and Azospirillum) were compared to those of Salmonella enterica sv. Typhimurium LPS. The biological activity of all the examined preparations, measured as Limulus lysate gelation, production of tumor necrosis factor (TNF), interleukin-1β (IL-1β), and interleukin-6 (IL-6), and nitrogen oxide (NO) induction in human myelomonocytic cells (line THP-1), was considerably lower than that of the reference enterobacterial endotoxin. Among the rhizobial lipopolysaccharides, the activities of Mesorhizobium huakuii and Azospirillum lipoferum LPSs were higher than those of the LPS preparations from five strains of Bradyrhizobium. The weak endotoxic activity of the examined preparations was correlated with differences in lipid A structure compared to Salmonella. © 2010 The Societies and Blackwell Publishing Asia Pty Ltd.

  17. [Identification of Azospirillum genus bacteria isolated from the spring wheat root zone].

    Science.gov (United States)

    Kopylov, Ie P; Spyrydonov, V H; Patyka, V P

    2009-01-01

    Bacteria with high N2-fixing activity were isolated from the root zone of spring wheat grown on leach chernozem and soddy podzolic soil in Ukrainian marshy woodlands. They were characterized by phenotypic signs and investigated with the help of molecular-genetic methods. On the basis of diagnostic signs the investigated strains were referred to Azospirillum brasilense from Azospirillum genus. Their 3'- and 5'-thermal 16S RNA hypervariable sites with length from 373 to 395 nucleotides were amplified and sequenced. The comparative analysis of results confirmed the 100% identity of 16S RNA sequences from investigated bacteria with the same sequences of A. brasilense from Gene Bank database. Thus the results of sequence analysis agree with results obtained during the investigation of phenotypic signs.

  18. Immunochemical characterization of the capsular polysaccharide of Azospirillum irakense KBC1.

    Science.gov (United States)

    Fedonenko, Yulia P; Burygin, Gennady L; Popova, Irina A; Sigida, Elena N; Surkina, Alina K; Zdorovenko, Evelina L; Konnova, Svetlana A

    2013-08-01

    The repeating unit structure of Azospirillum irakense KBC1 capsular polysaccharide (CPS) was established and was found to be identical to that of the O polysaccharide of A. irakense KBC1 lipopolysaccharide (LPS). The antigenic heterogeneity of the LPS and the CPS was shown to be related to differences in the macromolecular organization of these glycopolymers. After an immune response activation, R-form CPS molecules were found to be predominant.

  19. 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.

  20. Azospirillum spp. from native forage grasses in Brazilian Pantanal floodplain: biodiversity and plant growth promotion potential.

    Science.gov (United States)

    Souza, Mayara S T; de Baura, Valter A; Santos, Sandra A; Fernandes-Júnior, Paulo Ivan; Reis Junior, Fábio B; Marques, Maria Rita; Paggi, Gecele Matos; da Silva Brasil, Marivaine

    2017-04-01

    A sustainable alternative to improve yield and the nutritive value of forage is the use of plant growth-promoting bacteria (PGPB) that release nutrients, synthesize plant hormones and protect against phytopathogens (among other mechanisms). Azospirillum genus is considered an important PGPB, due to the beneficial effects observed when inoculated in several plants. The aim of this study was to evaluate the diversity of new Azospirillum isolates and select bacteria according to the plant growth promotion ability in three forage species from the Brazilian Pantanal floodplain: Axonopus purpusii, Hymenachne amplexicaulis and Mesosetum chaseae. The identification of bacterial isolates was performed using specific primers for Azospirillum in PCR reactions and partial sequencing of the 16S rRNA and nifH genes. The isolates were evaluated in vitro considering biological nitrogen fixation (BNF) and indole-3-acetic acid (IAA) production. Based on the results of BNF and IAA, selected isolates and two reference strains were tested by inoculation. At 31 days after planting the plant height, shoot dry matter, shoot protein content and root volume were evaluated. All isolates were able to fix nitrogen and produce IAA, with values ranging from 25.86 to 51.26 mg N mL -1 and 107-1038 µmol L -1 , respectively. The inoculation of H. amplexicaulis and A. purpusii increased root volume and shoot dry matter. There were positive effects of Azospirillum inoculation on Mesosetum chaseae regarding plant height, shoot dry matter and root volume. Isolates MAY1, MAY3 and MAY12 were considered promising for subsequent inoculation studies in field conditions.

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

    OpenAIRE

    N. Aliasgharzad, N. Aliasgharzad; Heydaryan, Zahra; Sarikhani, M.R

    2014-01-01

    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...

  2. Improved potato microclonal reproduction with the plant growth-promoting rhizobacteria Azospirillum

    OpenAIRE

    Tkachenko, Oksana V.; Evseeva, Nina V.; Boikova, Natalya V.; Matora, Larisa Yu.; Burygin, Gennady L.; Lobachev, Yuriy V.; Shchyogolev, Sergei Yu.

    2015-01-01

    International audience; AbstractMicroclonal propagation in vitro is being actively used in the production of healthy planting material of food and ornamental plants. However, it needs further improvement to increase the growth rates of microclones in vitro and enhance regenerant survivability ex vitro. A promising approach to this end could be inoculating in vitro-micropropagated plants with plant growth-promoting rhizobacteria, specifically Azospirillum. However, the influence of Azospirillu...

  3. Genome wide profiling of Azospirillum lipoferum 4B gene expression during interaction with rice roots.

    Science.gov (United States)

    Drogue, Benoît; Sanguin, Hervé; Borland, Stéphanie; Prigent-Combaret, Claire; Wisniewski-Dyé, Florence

    2014-02-01

    Azospirillum-plant cooperation has been mainly studied from an agronomic point of view leading to a wide description of mechanisms implicated in plant growth-promoting effects. However, little is known about genetic determinants implicated in bacterial adaptation to the host plant during the transition from free-living to root-associated lifestyles. This study aims at characterizing global gene expression of Azospirillum lipoferum 4B following a 7-day-old interaction with two cultivars of Oryza sativa L. japonica (cv. Cigalon from which it was originally isolated, and cv. Nipponbare). The analysis was done on a whole genome expression array with RNA samples obtained from planktonic cells, sessile cells, and root-adhering cells. Root-associated Azospirillum cells grow in an active sessile-like state and gene expression is tightly adjusted to the host plant. Adaptation to rice seems to involve genes related to reactive oxygen species (ROS) detoxification and multidrug efflux, as well as complex regulatory networks. As revealed by the induction of genes encoding transposases, interaction with root may drive bacterial genome rearrangements. Several genes related to ABC transporters and ROS detoxification display cultivar-specific expression profiles, suggesting host specific adaptation and raising the question of A. lipoferum 4B/rice cv. Cigalon co-adaptation. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  4. Response to saline stress and aquaporin expression in Azospirillum-inoculated barley seedlings.

    Science.gov (United States)

    Zawoznik, Myriam S; Ameneiros, Mayra; Benavides, María P; Vázquez, Susana; Groppa, María D

    2011-05-01

    The ability of two strains of Azospirillum brasilense to mitigate NaCl stress in barley plants was evaluated. Barley seedlings were inoculated and subjected to 200 mM NaCl for 18 days. Several days after NaCl treatment, a significant decline in biomass as well as in height was observed in uninoculated plants. However, smaller reductions in biomass and height were detected in plants inoculated with strain Az39. All the stressed plants showed significantly higher Na(+) but lower K(+) contents in their shoots. The growth rate of uninoculated plants was adversely affected by saline treatment, which was associated with higher putrescine content and lower levels of HvPIP2;1 transcripts in the roots. Azospirillum inoculation triggered the transcription of this gene. Our results suggest that barley plants inoculated with A. brasilense may be better prepared to thrive under saline conditions. To our knowledge, this is the first report showing an effect of Azospirillum inoculation on the expression of PIP2;1, a gene involved in the synthesis of root water channels.

  5. The plant growth-promoting bacteria Azospirillum amazonense: genomic versatility and phytohormone pathway.

    Science.gov (United States)

    Cecagno, Ricardo; Fritsch, Tiago Ebert; Schrank, Irene Silveira

    2015-01-01

    The rhizosphere bacterium Azospirillum amazonense associates with plant roots to promote plant growth. Variation in replicon numbers and rearrangements is common among Azospirillum strains, and characterization of these naturally occurring differences can improve our understanding of genome evolution. We performed an in silico comparative genomic analysis to understand the genomic plasticity of A. amazonense. The number of A. amazonense-specific coding sequences was similar when compared with the six closely related bacteria regarding belonging or not to the Azospirillum genus. Our results suggest that the versatile gene repertoire found in A. amazonense genome could have been acquired from distantly related bacteria from horizontal transfer. Furthermore, the identification of coding sequence related to phytohormone production, such as flavin-monooxygenase and aldehyde oxidase, is likely to represent the tryptophan-dependent TAM pathway for auxin production in this bacterium. Moreover, the presence of the coding sequence for nitrilase indicates the presence of the alternative route that uses IAN as an intermediate for auxin synthesis, but it remains to be established whether the IAN pathway is the Trp-independent route. Future investigations are necessary to support the hypothesis that its genomic structure has evolved to meet the requirement for adaptation to the rhizosphere and interaction with host plants.

  6. Seed inoculation with Azospirillum brasilense and N fertilization of corn in the Cerrado biome

    Directory of Open Access Journals (Sweden)

    Ana Carolina Pereira de Vasconcelos

    Full Text Available ABSTRACT There is a great interest to reduce doses and increase efficiency of inputs in agriculture. One alternative to lower doses of N fertilizers in corn is seed inoculation with diazotrophic bacteria, which can fix atmospheric N in soil. This study aimed to evaluate the effect of N doses-in the absence and presence of Azospirillum brasilense-on plant nutritional status at different growth stages and on seed yield of corn. The experiment was conducted during the 2011/2012 production season on a typical cerrado soil in Uberlândia, Triângulo Mineiro. The experimental design was randomized blocks with six repetitions. The treatments consisted of five N doses and the absence or presence of Azospirillum brasilense (100 mL ha-1 as a seed inoculant. A commercial product with minimum concentration of 2x108 CFU mL-1 100 mL ha-1 was used. Inoculation with Azospirillum brasilense did not significantly affect corn macronutrient content and yield, except for foliar calcium and potassium at 200 kg N ha-1 at the V8 stage. Corn yield increased with N doses up to 150 kg N ha-1.

  7. The Plant Growth-Promoting Bacteria Azospirillum amazonense: Genomic Versatility and Phytohormone Pathway

    Directory of Open Access Journals (Sweden)

    Ricardo Cecagno

    2015-01-01

    Full Text Available The rhizosphere bacterium Azospirillum amazonense associates with plant roots to promote plant growth. Variation in replicon numbers and rearrangements is common among Azospirillum strains, and characterization of these naturally occurring differences can improve our understanding of genome evolution. We performed an in silico comparative genomic analysis to understand the genomic plasticity of A. amazonense. The number of A. amazonense-specific coding sequences was similar when compared with the six closely related bacteria regarding belonging or not to the Azospirillum genus. Our results suggest that the versatile gene repertoire found in A. amazonense genome could have been acquired from distantly related bacteria from horizontal transfer. Furthermore, the identification of coding sequence related to phytohormone production, such as flavin-monooxygenase and aldehyde oxidase, is likely to represent the tryptophan-dependent TAM pathway for auxin production in this bacterium. Moreover, the presence of the coding sequence for nitrilase indicates the presence of the alternative route that uses IAN as an intermediate for auxin synthesis, but it remains to be established whether the IAN pathway is the Trp-independent route. Future investigations are necessary to support the hypothesis that its genomic structure has evolved to meet the requirement for adaptation to the rhizosphere and interaction with host plants.

  8. Reorganization of Azospirillum brasilense cell membrane is mediated by lipid composition adjustment to maintain optimal fluidity during water deficit.

    Science.gov (United States)

    Cesari, A B; Paulucci, N S; Biasutti, M A; Reguera, Y B; Gallarato, L A; Kilmurray, C; Dardanelli, M S

    2016-01-01

    We study the Azospirillum brasilense tolerance to water deficit and the dynamics of adaptive process at the level of the membrane. Azospirillum brasilense was exposed to polyethylene glycol (PEG) growth and PEG shock. Tolerance, phospholipids and fatty acid (FA) composition and membrane fluidity were determined. Azospirillum brasilense was able to grow in the presence of PEG; however, its viability was reduced. Cells grown with PEG showed membrane fluidity similar to those grown without, the lipid composition was modified, increasing phosphatidylcholine and decreasing phosphatidylethanolamine amounts. The unsaturation FAs degree was reduced. The dynamics of the adaptive response revealed a decrease in fluidity 20 min after the addition of PEG, indicating that the PEG has a fluidizing effect on the hydrophobic region of the cell membrane. Fluidity returned to initial values after 60 min of PEG exposure. Azospirillum brasilense is able to perceive osmotic changes by changing the membrane fluidity. This effect is offset by changes in the composition of membrane phospholipid and FA, contributing to the homeostasis of membrane fluidity under water deficit. This knowledge can be used to develop new Azospirillum brasilense formulations showing an adapted membrane to water deficit. © 2015 The Society for Applied Microbiology.

  9. [Isolation and characterization of nitrogen-fixing bacteria of the genus Azospirillum from the soil of a Sphagnum peat bog].

    Science.gov (United States)

    Doroshenko, E V; Bulygina, E S; Spiridonova, E M; Turova, T P; Kravchenko, I K

    2007-01-01

    The presence of nitrogen-fixing bacteria of the genus Azospirillum in the soils of acidic raised Sphagnum bogs is revealed for the first time. Three Azospirillum strains, B2, B21, and B22, were isolated as a component of methane-oxidizing enrichment cultures, whereas attempts to isolate them directly from peat samples have failed. The results of comparative analysis of the nucleotide sequences of 16S rRNA genes, DNA-DNA hybridization, and the analysis of the sequences of the functional genes encoding nitrogenase and ribulose-1, 5-bisphosphate carboxylase reveal that all the newly obtained strains can be classified as Azospirillum lipoferum. Yet, unlike A. lipoferum. the isolates do not require biotin and utilize sucrose, inositol, and glycerol for growth. The cell morphology of strain B2 differs from that of the type strain and strains B21 and B22. The results obtained indicate the variability of morphological, physiological, and biochemical properties in closely related Azospirillum strains and suggest the existence of metabolic relationships between methanotrophic bacteria and the representatives of the genus Azospirillum under peat bog conditions.

  10. Changes in Nutrient Content of Root and Grain of Wheat Cultivars Inoculated by Azospirillum and Mycorrhiza

    Directory of Open Access Journals (Sweden)

    M. Jiriaie

    2016-02-01

    Full Text Available Introduction: Providing the nutritional requirements of agricultural crops by non-chemical resources is a new approach in the organic farming that has attracted the attention of both the researchers and the consumers in recent years. Therefore, it is highly important to find new fertilizer resources that are both economically able to provide the nutritional needs of the crop plants and have no adverse effects on the consumers and the environment. Materials and Methods: With this approach, an experiment was conducted in the research station of Shahid Chamran University of Ahvaz, Iran in 2012-13. The experimental design was factorial based on randomized complete blocks design with three replications. The treatments including Mycorrhizal fungi in three levels (i.e. no use of strain; use of Glomus intraradices strain; and use of Glomus mosseae strain, bacteria Azospirillum lipoferum in two-levels (i.e. non-inoculated and inoculated and wheat cultivars in three levels (i.e. Chamran; Dena; and Behrang. The measured parameters include the concentration of macronutrients (i.e. nitrogen, phosphorus and potassium and some micronutrients (i.e. zinc, iron and manganese in two part seed and the root of wheat. Results and Discussion: Surveying the elements content in the root and the grain indicated a significant and positive effect of the use the Azospirillum and Mycorrhiza to improve the concentration of the elements in wheat cultivars. However, the simultaneous use of these microorganisms led to an increase of the effects of their application on their assessed traits.Finally the highest concentration of N (2.21 present, P (0.50 present and Fe (33.88 mg.kg-1 were observed in the grain; the highest concentration of K (0.93 present and 0.54 present and Mn (43.11 and 23.63 mg.kg-1 were observed in the grain and root, respectively. Moreover, the highest concentration of Zn in the root (19.70 mg.kg-1 was obtained from inoculation of C.V Dena seeds with

  11. 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. Copyright © 2011 Elsevier GmbH. All rights reserved.

  12. 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.

  13. Technical and economic viability of co-inoculation with Azospirillum brasilense in soybean cultivars in the Cerrado

    Directory of Open Access Journals (Sweden)

    Fernando S. Galindo

    Full Text Available ABSTRACT Biological nitrogen fixation (BNF efficiency can be increased by co-inoculation with bradyrhizobia and Azospirillum brasilense, allowing even greater uptake of water and nutrients, leading to higher yields. Thus, this study aimed to evaluate the technical and economic viability of soybean in the Cerrado, according to the cultivars and co-inoculation with Azospirillum brasilense. The experiment was conducted in Selvíria, MS, in no-tillage system, in Oxisol, arranged in a randomized block design in a 2 x 2 factorial scheme with two cultivars (‘Potência’ and ‘Valiosa’, with and without co-inoculation with Azospirillum brasilense in the seed. Co-inoculation with A. brasilense increases grain yield in the cultivars ‘Potência’ and ‘Valiosa’, being economically viable. However, using the cultivar ‘Potência’ co-inoculated led to the highest profitability.

  14. 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.

  15. A Phase Variant of Azospirillum lipoferum Lacks a Polar Flagellum and Constitutively Expresses Mechanosensing Lateral Flagella

    Science.gov (United States)

    Alexandre, Gladys; Rohr, René; Bally, René

    1999-01-01

    Flagellation of a nonswimming variant of the mixed flagellated bacterium Azospirillum lipoferum 4B was characterized by electron microscopy, and polyclonal antibodies were raised against polar and lateral flagellins. The variant cells lacked a polar flagellum due to a defect in flagellin synthesis and constitutively expressed lateral flagella. The variant cells were able to respond to conditions that restricted the rotation of lateral flagella by producing more lateral flagella, suggesting that the lateral flagella, as well as the polar flagellum, are mechanosensing. PMID:10508112

  16. 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.

  17. The evaluation of IAA-production ability in indigenous Azospirillum isolates and their growth promoting effects on sweet corn

    Directory of Open Access Journals (Sweden)

    mahdi arab

    2009-06-01

    Full Text Available It has been years that Azospirillum is known to promote plant growth. Phytohormone (especially Auxin production has the most important role in increasing the yield of inoculated plants. According to this, 60 strains of this genus were isolated, identified, and purified. This ability was evaluated in both qualitative and quantitative assays using colorimetric method and the effects of superior isolate on sweet corn were measured. Results revealed that the abundance and probability of the bacteria isolation is low and 17%. About 31.2% and 100% of Azospirillum strains were capable of producing IAA in qualitative and quantitative methods respectively. In greenhouse experiment, bacteria treatments had significant effects on corn fresh weight, total dry weight, root dry weight and total nitrogen and phosphorus content of the plant. This was considered to be as the result of more lateral root formation which enhances nutrition uptake. In conclusion, the green house results in respect to in vitro achievements show that fortunately it can be claimed that bacteria of the genus Azospirillum can be used widely for not only strategic gramineous plants like: corn, wheat, barely etc. but also for other useful plants. Key words: Azospirillum, Auxin, qualitative and quantitative methods, sweet corn.

  18. Residual phosphate fertilization and Azospirillum brasilense in the common bean in succession to maize intercropped with Marandu grass

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    Lourdes Dickmann

    Full Text Available ABSTRACT One of the alternatives for achieving sustainable agriculture and a reduction in production costs, especially with phosphate fertilisers, is to inoculate seeds with bacteria of the genus Azospirillum. The aim of this study therefore, was to evaluate residual phosphate fertilisation and Azospirillum brasilense, together with the contribution of straw from maize intercropped with Marandu grass, on leaf nutritional content, yield components and winter bean yield. The experiment was carried out on the Teaching and Research Farm, of the School of Engineering at UNESP, located in Selvíria in the State of Mato Grosso do Sul, in a typic clayey dystrophic Red Latosol. The experimental design was of randomised blocks with four replications in a 5 x 2 factorial scheme. The treatments consisted of beans sown on straw from maize intercropped with Marandu grass on areas that had received five levels of P2O5 in the form of MAP, applied during an initial cultivation of black oats (0, 30, 60, 120 and 240 kg ha-1, both with and without inoculation of the oat and maize which preceded the beans with Azospirillum brasilense. Leaf nutrient content, leaf chlorophyll index (ICF, yield components and bean productivity were all evaluated. Inoculation with Azospirillum brasilense of the black oat and maize seeds improved the nutritional status of the plants, but had a negative effect on grain yield. Fertilisation of the oat crop with phosphorus had a positive residual effect on the beans, with increases in yield components and grain yield.

  19. Pengaruh pupuk kandang dan NPK terhadap populasi bakteri Azotobacter dan Azospirillum dalam tanah pada budidaya cabai (Capsicum annum

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    MUJIYATI

    2009-11-01

    Full Text Available Mujiyati, Supriyadi. 2009. Pengaruh pupuk kandang dan NPK terhadap populasibakteri Azotobacter dan Azospirillum dalam tanah pada budidaya cabai (Capsicumannum. Bioteknologi 6: 63-69. Tujuan penelitian ini adalah mengetahui peningkatan populasi bakteri Azotobacter dan Azospirillum akibat pemberian pupuk kandang. Percobaan menggunakan rancangan acak kelompok dengan perlakuan: (i tanpa pupuk sebagai kontrol, (ii dengan pupuk kandang, (iii dengan pupuk NPK. Data dikumpulkan secara eksperimen dengan menanam cabai pada beberapa petak percobaan dengan perlakuan penggunaan pupuk sebanyak tiga kali ulangan. Data yang dikumpulkan terdiri atas jumlah populasi Azotobacter dan Azospirillum, kandungan nitrogen dalam tanah dan hasil cabai. Percobaan lapangan dilakukan di Desa Gathak, Kecamatan Karangnongko, Kabupaten Klaten, Jawa Tengah. Data primer dari hasil penelitian di analisis dengan uji ANAVA dan dilanjutkan dengan uji BNT dengan tingkat kepercayaan 95%. Hasil penelitian menunjukkan bahwa menggunakan pupuk kandang dapat meningkatkan populasi bakteri Azotobacter (0,02% dan Azospirillum (0,46% apabila dibandingkan kontrol, sehingga dapat meningkatkan kesuburan tanah dalam waktu yang cukup lama yaitu dengan meningkatkan ketersediaan hara dalam tanah. Kandungan nitrogen total tanah setelah diberi pupuk kandang juga meningkat dan sangat bermanfaat untuk bahan penyusun tubuh tumbuhan.

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

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    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.

  1. Activation of a calcium-dependent protein kinase involved in the Azospirillum growth promotion in rice.

    Science.gov (United States)

    Ribaudo, Claudia M; Curá, José A; Cantore, María L

    2017-02-01

    Rice seedlings (Oryza sativa) inoculated with the plant growth-promoting rhizobacteria Azospirillum brasilense FT326 showed an enhanced development of the root system 3 days after inoculation. Later on, a remarkable enlargement of shoots was also evident. An increase in the Ca 2+ -dependent histone kinase activity was also detected as a result of inoculation. The biochemical characterization and Western-blot analysis of the kinase strongly supports the hypothesis that it belongs to a member of the rice CDPK family. The fact that the amount of the protein did not change upon inoculation seems to indicate that a posttranslational activation is responsible for the change in the enzymatic activity. An in-gel kinase experiment identified a 46 kDa CDPK like protein kinase as a putative component of the signal transduction pathway triggered by Azospirillum inoculation. To our knowledge, this is the first report on the possible involvement of a Ca 2+ -dependent protein kinase in promotion of rice plants growth by A. brasilense.

  2. 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.

  3. Doses and application methods of Azospirillum brasilense in irrigated upland rice

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    Nayara F. S. Garcia

    Full Text Available ABSTRACT The study was carried out in Selvíria-MS, in the 2011/12 and 2012/13 agricultural years, aiming to evaluate the efficiency of Azospirillum brasilense in nitrogen fixation in upland rice, as a function of doses and application methods of the inoculant containing this diazotrophic bacterium. The experimental design was randomized blocks, arranged in a 4 x 4 factorial scheme, with 4 doses of inoculant (control without inoculation, 100, 200 and 300 mL of the commercial product ha-1 and 4 application methods (seed inoculation, application in the sowing furrow, soil spraying after sowing, and foliar spraying at the beginning of plant tillering, with 4 replicates. During the experiment, the agronomic characteristics, production components and yield of the rice crop were evaluated. It was concluded that the inoculant containing Azospirillum brasilense promotes increase (19% in the yield of upland rice under sprinkler irrigation when used at the dose of 200 mL ha-1, regardless of the application methods.

  4. 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.

  5. 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. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  6. بررسی سودمندی قارچ اندوفیت Piriformospora indica و باکتری Azospirillum Sp. در افزایش تحمل گندم رقم سرداری (Triticum aestivum به تنش شوری

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    سمیه حاجی نیا

    2011-08-01

    Full Text Available شوری آب و خاک یکی از مشکلات جدی و رو به توسعه در سطح جهان است، که سطح وسیعی از اراضی کشور نیز با این مشکل مواجه هستند. کاربرد میکروارگانیسم‌‌های اندوفیت که از مهمترین میکروارگانیسم‌‌های خاک محسوب می‌شوند، در کاهش تنش‌‌‌­های محیطی مانند شوری، به یک راهکار جهانی تبدیل شده است. بنابراین به منظوربررسی اثرات تلقیح قارچ اندوفیت Piriformospora indica و ریزوباکتریهای افزاینده رشد گیاه .Azospirillum sp بر رشد و خصوصیات فیزیولوژیکی گیاه گندم تحت تنش شوری، آزمایشی به صورت فاکتوریل در قالب طرح بلوک‌­های کامل تصادفی با سه تکرار در پاییز سال 1389 در گلخانه تحقیقاتی دانشکده کشاورزی دانشگاه ایلام اجرا گردید. تیمارهای آزمایشی شامل کاربرد پنج سطح میکروارگانیسم‌­های اندوفیت (قارچ پیریفورموسپورا ایندیکا، باکتری آزوسپیریلوم سویه‌های سازگار به مناطق شور و غیر شور، تلقیح توأم قارچ و باکتری و شاهد و چهار سطح شوری آب آبیاری (2/0، 4، 8 و 12 دسی زیمنس بر متر بود. نتایج نشان داد که قارچ پیریفورموسپورا ایندیکا تأثیر مثبت و معنی‌­داری بر رشد، میزان زیتوده تر و خشک اندام‌های هوایی، کلروفیل و محلول‌های اسمولیت در گیاهان گندم تلقیح شده تحت شرایط شور و غیر شور داشت، به طوری که کاربرد قارچ منجر به کاهش اثرات سوء شوری و

  7. 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.

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

    OpenAIRE

    Katty Baca; Melgy Sánchez; Carmen Carreño; Gilmar Mendoza

    2010-01-01

    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, obtaine...

  9. Genomic insights into the versatility of the plant growth-promoting bacterium Azospirillum amazonense.

    Science.gov (United States)

    Sant'Anna, Fernando H; Almeida, Luiz G P; Cecagno, Ricardo; Reolon, Luciano A; Siqueira, Franciele M; Machado, Maicon R S; Vasconcelos, Ana T R; Schrank, Irene S

    2011-08-12

    The species Azospirillum amazonense belongs to a well-known genus of plant growth-promoting bacteria. This bacterium is found in association with several crops of economic importance; however, there is a lack of information on its physiology. In this work, we present a comprehensive analysis of the genomic features of this species. Genes of A. amazonense related to nitrogen/carbon metabolism, energy production, phytohormone production, transport, quorum sensing, antibiotic resistance, chemotaxis/motility and bacteriophytochrome biosynthesis were identified. Noteworthy genes were the nitrogen fixation genes and the nitrilase gene, which could be directly implicated in plant growth promotion, and the carbon fixation genes, which had previously been poorly investigated in this genus. One important finding was that some A. amazonense genes, like the nitrogenase genes and RubisCO genes, were closer phylogenetically to Rhizobiales members than to species of its own order. The species A. amazonense presents a versatile repertoire of genes crucial for its plant-associated lifestyle.

  10. Structural peculiarities of the O-specific polysaccharides of Azospirillum bacteria of serogroup III.

    Science.gov (United States)

    Fedonenko, Yu P; Boiko, A S; Zdorovenko, E L; Konnova, S A; Shashkov, A S; Ignatov, V V; Knirel, Yu A

    2011-07-01

    Lipopolysaccharides and O-specific polysaccharides were isolated from the outer membrane of bacterial cells of three strains belonging to two Azospirillum species, and their structures were established by monosaccharide analysis including determination of the absolute configurations, methylation analysis, and one- and two-dimensional NMR spectroscopy. It was shown that while having the identical composition, the O-polysaccharides have different branched tetrasaccharide repeating units. Two neutral polysaccharides were found in the lipopolysaccharide of A. brasilense 54, and the structure for the predominant O-polysaccharide was determined. The structural data, together with results of serological studies, enabled assignment of strains examined to a novel serogroup, III. The chemical basis for the serological relatedness among the azospirilla of this serogroup is presumably the presence of a common →3)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap-(1→ oligosaccharide motif in their O-polysaccharides.

  11. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Auxins Upregulate Expression of the Indole-3-Pyruvate Decarboxylase Gene in Azospirillum brasilense

    Science.gov (United States)

    Vande Broek, Ann; Lambrecht, Mark; Eggermont, Kristel; Vanderleyden, Jos

    1999-01-01

    Transcription of the Azospirillum brasilense ipdC gene, encoding an indole-3-pyruvate decarboxylase involved in the biosynthesis of indole-3-acetic acid (IAA), is induced by IAA as determined by ipdC-gusA expression studies and Northern analysis. Besides IAA, exogenously added synthetic auxins such as 1-naphthaleneacetic acid, 2,4-dichlorophenoxypropionic acid, and p-chlorophenoxyacetic acid were also found to upregulate ipdC expression. No upregulation was observed with tryptophan, acetic acid, or propionic acid or with the IAA conjugates IAA ethyl ester and IAA-l-phenylalanine, indicating structural specificity is required for ipdC induction. This is the first report describing the induction of a bacterial gene by auxin. PMID:9973364

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

    OpenAIRE

    Yudyt Díaz-Saez; Manuel Díaz-de los Ríos; Mario Alberto-Casas; Arianna Nuñez-Caraballo; Marlene Martínez-Mora

    2013-01-01

    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 má...

  14. INFLUÊNCIA DO THIDIAZURON E DA INOCULAÇÃO COM Azospirillum brasilense NO CRESCIMENTO E PRODUTIVIDADE DO ARROZ DE TERRAS ALTAS / INFLUENCE OF THIDIAZURON AND INOCULATION WITH Azospirillum brasilense IN THE GROWTH AND PRODUCTIVITY OF HIGHLAND RICE

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    L. M. Garé

    2017-12-01

    Full Text Available A inoculação com bactérias do gênero Azospirillum pode contribuir com o fornecimento de nitrogênio (N e com o crescimento das plantas, pois esses microrganismos são também promotores de crescimento. Por outro lado a aplicação nas doses e épocas adequadas do regulador vegetal de efeito citocinínico thidiazuron (TDZ pode vir a beneficiar a produtividade de grãos. Dessa maneira, o objetivo do trabalho foi avaliar o efeito de doses de TDZ sobre a produtividade do arroz, na presença e ausência da inoculação foliar com Azospirillum brasilense. Foi utilizada a cultivar ANa 5015, no delineamento experimental de blocos casualizados em esquema fatorial 4 x 2, sendo quatro doses de TDZ (0,0; 0,5; 1,0 e 1,5g ha-1 aplicadas por ocasião do perfilhamento, 30 DAE, e da aplicação de Azospirillum brasilense (presença ou ausência em dose fixa aos 20 DAE. Verificou-se que a cultivar ANa 5015 não se mostrou responsiva para a inoculação foliar com Azospirillum brasilense na dose de 200 mL ha-1. Para as doses de TDZ aplicadas via foliar, houve uma variação significativa na altura de plantas, cuja dose de 0,41 g ha-1 resultou na altura máxima de 1,11 m. Não houve efeito das doses de TDZ na produtividade, massa de 100 grãos, número de panículas por m², grãos por panícula e massa hectolítrica.

  15. [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.

  16. 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.

  17. Cellulose Decomposition and Associated Nitrogen Fixation by Mixed Cultures of Cellulomonas gelida and Azospirillum Species or Bacillus macerans

    Science.gov (United States)

    Halsall, Dorothy M.; Gibson, Alan H.

    1985-01-01

    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 g 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% O2 (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. PMID:16346898

  18. 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.

  19. Host plant secondary metabolite profiling shows a complex, strain-dependent response of maize to plant growth-promoting rhizobacteria of the genus Azospirillum.

    Science.gov (United States)

    Walker, Vincent; Bertrand, Cédric; Bellvert, Floriant; Moënne-Loccoz, Yvan; Bally, René; Comte, Gilles

    2011-01-01

    Most Azospirillum plant growth-promoting rhizobacteria (PGPR) benefit plant growth through source effects related to free nitrogen fixation and/or phytohormone production, but little is known about their potential effects on plant physiology. These effects were assessed by comparing the early impacts of three Azospirillum inoculant strains on secondary metabolite profiles of two different maize (Zea mays) cultivars. After 10d of growth in nonsterile soil, maize methanolic extracts were analyzed by reverse-phase high-performance liquid chromatography (RP-HPLC) and secondary metabolites identified by liquid chromatography/mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR). Seed inoculation resulted in increased shoot biomass (and also root biomass with one strain) of hybrid PR37Y15 but had no stimulatory effect on hybrid DK315. In parallel, Azospirillum inoculation led to major qualitative and quantitative modifications of the contents of secondary metabolites, especially benzoxazinoids, in the maize plants. These modifications depended on the PGPR strain×plant cultivar combination. Thus, Azospirillum inoculation resulted in early, strain-dependent modifications in the biosynthetic pathways of benzoxazine derivatives in maize in compatible interactions. This is the first study documenting a PGPR effect on plant secondary metabolite profiles, and suggests the establishment of complex interactions between Azospirillum PGPR and maize. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

  20. Molecular identification of Azospirillum spp.: Limitations of 16S rRNA and qualities of rpoD as genetic markers.

    Science.gov (United States)

    Maroniche, Guillermo A; García, Julia E; Salcedo, Florencia; Creus, Cecilia M

    2017-01-01

    Since their discovery, plant-growth promoting rhizobacteria from the genus Azospirillum have been subjected to intensive research due to their biotechnological potential as crop inoculants. Phylogenetic analysis of Azospirillum spp. is carried out by 16S rRNA sequencing almost exclusively, but inconsistencies and low confidence often arise when working with close species. In this work, it was observed that these difficulties might be explained by a high number of rRNA operons with considerable inter-genic variability within Azospirillum genomes. To search for alternative genetic markers from a list of housekeeping genes, the correlation between pairwise gene and whole-genome similarities was examined. Due to its good performance, rpoD was selected for further analyses. Genus-specific primers for the PCR-amplification and sequencing of rpoD from Azospirillum spp. were designed and tested on 16 type strains of different species. The sequences obtained were used for inferring a phylogenetic tree of the genus, which was in turn used as a reference to successfully identify a collection of 31 azospirilla isolated from many different locations of Argentine. In addition, several strains that might represent novel species were detected. The results indicate that the sequencing of rpoD is a suitable alternative method for a confident molecular identification in Azospirillum spp. Copyright © 2016 Elsevier GmbH. All rights reserved.

  1. SP. Pescado

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    Renato Gendre

    2003-12-01

    Full Text Available Nell'occhiello di un articolo dal titolo Il Peru dei de[Jini rosa e de/la grande pioggia si legge: "da una partenza  in aereo al «pescado»  che ti  sfamera."1 Questa parola spagnola, giustamente chiusa tra caporali, a noi pare molto interes­ sante, perche, nonostante l'apparenza, non ha nulla da spartire sotto i1 profilo se­ mantico con l'it. pescato. lnfatti, tutti i piu importanti dizionari della lingua italiana, di ieri e di oggi, etimologici e non 2, registrano  accanto a pescata,  ii lemma pescato, 3 ma lo spiegano come "quantita di pesce catturato nel corso di una battuta o di una stagione di pesca",4 mentre lo sp. pescado  indica i1 "pesce (solo nel senso di: pesGe pescato da mangiare [...]".s

  2. 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.

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

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    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.

  4. Coexistence and survival of pathogenic leptospires by formation of biofilm with Azospirillum.

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    Kumar, K Vinod; Lall, Chandan; Raj, R Vimal; Vedhagiri, K; Vijayachari, P

    2015-06-01

    Pathogenic Leptospira spp. represent one cause of leptospirosis worldwide and have long been regarded as solitary organisms in soil and aquatic environments. However, in the present study, Leptospira interrogans was observed to be associated with environmental biofilms with 21 bacterial isolates belonging to 10 genera. All 21 isolates were examined for their coaggregation and biofilm-forming ability with leptospires in vitro. Among these, Azospirillum brasilense RMRCPB showed maximum interspecies coaggregation with leptospiral strains (>75%, visual score of +4). Other significant coaggregating isolates belonged to the genera Sphingomonas, Micrococcus, Brevundimonas, Acinetobacter and Paracoccus. Biofilms of leptospires in combination with A. brasilense RMRCPB showed high resistance to penicillin G, ampicillin and tetracycline (minimum bactericidal concentration ≥800 μg/mL) and tolerance to UV radiation and high temperature (up to 49°C). This study hypothesized that biofilm formation with A. brasilense protects the pathogenic Leptospira from adverse environmental conditions/stress. This coexistence of pathogenic Leptospira with other bacteria may be the key factor for its persistence and survival. However, the mechanism of biofilm formation by leptospires needs to be explored to help devise an appropriate control strategy and reduce transmission of leptospires. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Rhizobial Inoculation, Alone or Coinoculated with Azospirillum brasilense, Promotes Growth of Wetland Rice

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    Leandro Hahn

    Full Text Available ABSTRACT Rhizobia and associative bacteria promote growth in rice plants (Oryza sativa L. through a series of mechanisms, but most studies on inoculation have been performed based on inoculation with these bacteria in a separate or singular manner. The objective of this study was to assess the efficiency of single/isolated inoculation and inoculation combined with symbiotic rhizobia from forage legume and with Azospirillum brasilense on promoting growth and the root colonization process in wetland rice. Two rhizobia among four isolates from a greenhouse and a laboratory experiment were selected that efficiently promoted seed germination and rice plant growth in a sterilized substrate and in soil. The two most efficient isolates (UFRGS Vp16 and UFRGS Lc348 were inoculated alone or in combination with a commercial product containing A. brasilense in two field experiments using two wetland rice cultivars over two growing seasons. In the field experiments, these isolates coinoculated with A. brasilense promoted larger increases in the agronomic variables of wetland rice compared to the control without inoculation. Confocal laser microscopy confirmed the presence of inoculated bacteria tagged with gfp (UFRGS Vp16, UFRGS Lc348, and A. brasilense colonizing the root surface of the rice seedlings, mainly in the root hairs and lateral roots.

  6. Tools for genetic manipulation of the plant growth-promoting bacterium Azospirillum amazonense.

    Science.gov (United States)

    Sant'anna, Fernando H; Andrade, Dieime S; Trentini, Débora B; Weber, Shana S; Schrank, Irene S

    2011-05-16

    Azospirillum amazonense has potential to be used as agricultural inoculant since it promotes plant growth without causing pollution, unlike industrial fertilizers. Owing to this fact, the study of this species has gained interest. However, a detailed understanding of its genetics and physiology is limited by the absence of appropriate genetic tools for the study of this species. Conjugation and electrotransformation methods were established utilizing vectors with broad host-replication origins (pVS1 and pBBR1). Two genes of interest--glnK and glnB, encoding PII regulatory proteins--were isolated. Furthermore, glnK-specific A. amazonense mutants were generated utilizing the pK19MOBSACB vector system. Finally, a promoter analysis protocol based on fluorescent protein expression was optimized to aid genetic regulation studies on this bacterium. In this work, genetic tools that can support the study of A. amazonense were described. These methods could provide a better understanding of the genetic mechanisms of this species that underlie its plant growth promotion.

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

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    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. 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.

  9. 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. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  10. Mitigation of salt stress in white clover (Trifolium repens) by Azospirillum brasilense and its inoculation effect.

    Science.gov (United States)

    Khalid, Muhammad; Bilal, Muhammad; Hassani, Danial; Iqbal, Hafiz M N; Wang, Hang; Huang, Danfeng

    2017-12-01

    Salinity is one of the increasingly serious environmental problems worldwide for cultivating agricultural crops. The present study was aimed to ascertain the potential of beneficial soil bacterium Azospirillum brasilense to alleviate saline stress in Trifolium repens. Experimental plants (white clover) were grown from seeds and inoculated with or without A. brasilense bacterial strain supplemented with 0, 40, 80, or 120 mM NaCl into soil. The growth attributes including, shoot heights, root lengths, fresh and dry weights, leaf area and chlorophyll content were significantly enhanced in T. repens plants grown in A. brasilense inoculated soil than un-inoculated controls, particularly under elevated salinity conditions (40, 80 and 120 mM NaCl). Malondialdehyde content of leaf was recorded to be declined under saline conditions. Moreover, the K + /Na + ratio was also improved in bacterium-inoculated plants, since A. brasilense significantly reduced the root and shoot Na + level under high salty environment. Results revealed that soil inoculation with A. brasilense could significantly promote T. repens growth under both non-saline and saline environments, and this study might be extended to other vegetables and crops for the germination and growth enhancement.

  11. 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.

  12. Tiller density and tillering on Brachiaria brizantha cv. Marandu pastures inoculated with Azospirillum brasilense

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    B.C. Pedreira

    Full Text Available ABSTRACT The objective of this study is to verify the population density and the dynamics of tillering in the Marandu palisade grass sward subjected to nitrogen (N fertilization strategies, characterized by the N supply via urea or bacterial inoculant (Azospirillum brasilense. The treatments comprised of four nitrogen fertilization strategies: (A Without fertilization, (B 80 kg N/ha, (C inoculant (A. brasilense, and (D 80 kg N/ha + inoculant, distributed in a randomized complete block design, with three replications. The nitrogen supply strategies were evaluated during six periods: October, November, and December (2012 as well as January, March, and April (2013. The nitrogen dose or inoculant had no effect on the tiller appearance rate (TAR, tiller mortality rate (TMR, tiller survival rate (TSR, or tiller population density (TPD. However, these variables were influenced by the season. The TAR and TSR were higher at the beginning of the experimental period (October and lower towards the end of the period (March-April, whereas, TMR and TPD exhibited the opposite behavior, with lower values in October and higher from January onward. Neither the nitrogen nor the inoculant influenced the population dynamics of the tillers in Marandu palisade grass.

  13. Compatibility of Azospirillum brasilense and Pseudomonas fluorescens in growth promotion of groundnut ( Arachis hypogea L.

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    ANDHARE A. PRASAD

    Full Text Available ABSTRACT We attempted to study the compatibility among plant beneficial bacteria in the culture level by growing them near in the nutrient agar plates. Among all the bacteria tested, Rhizobium was found to inhibit the growth of other bacteria. From the compatible group of PGPR, we have selected one biofertilizer (Azospirillum brasilense strain TNAU and one biocontrol agent (Pseudomonas fluorescens strain PF1 for further studies in the pot culture. We have also developed a bioformulation which is talc powder based, for individual bacteria and mixed culture. This formulation was used as seed treatment, soil application, seedling root dip and foliar spray in groundnut crop in vitro germination conditions. A. brasilense was found to enhance the tap root growth and P. fluorescens, the lateral root growth. The other growth parameters like shoot growth, number of leaves were enhanced by the combination of both of the bacteria than their individual formulations. Among the method of application tested in our study, soil application was found to be the best in yielding better results of plant growth promotion.

  14. 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.

  15. Compatibility of Azospirillum brasilense and Pseudomonas fluorescens in growth promotion of groundnut ( Arachis hypogea L.).

    Science.gov (United States)

    Prasad, Andhare A; Babu, Subramanian

    2017-01-01

    We attempted to study the compatibility among plant beneficial bacteria in the culture level by growing them near in the nutrient agar plates. Among all the bacteria tested, Rhizobium was found to inhibit the growth of other bacteria. From the compatible group of PGPR, we have selected one biofertilizer (Azospirillum brasilense strain TNAU) and one biocontrol agent (Pseudomonas fluorescens strain PF1) for further studies in the pot culture. We have also developed a bioformulation which is talc powder based, for individual bacteria and mixed culture. This formulation was used as seed treatment, soil application, seedling root dip and foliar spray in groundnut crop in vitro germination conditions. A. brasilense was found to enhance the tap root growth and P. fluorescens, the lateral root growth. The other growth parameters like shoot growth, number of leaves were enhanced by the combination of both of the bacteria than their individual formulations. Among the method of application tested in our study, soil application was found to be the best in yielding better results of plant growth promotion.

  16. 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.

  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. 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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. (Methyl)ammonium Transport in the Nitrogen-Fixing Bacterium Azospirillum brasilense

    Science.gov (United States)

    Van Dommelen, Anne; Keijers, Veerle; Vanderleyden, Jos; de Zamaroczy, Miklos

    1998-01-01

    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. PMID:9573149

  20. Expressed sequence tags related to nitrogen metabolism in maize inoculated with Azospirillum brasilense.

    Science.gov (United States)

    Pereira-Defilippi, L; Pereira, E M; Silva, F M; Moro, G V

    2017-05-31

    The relative quantitative real-time expression of two expressed sequence tags (ESTs) codifying for key enzymes in nitrogen metabolism in maize, nitrate reductase (ZmNR), and glutamine synthetase (ZmGln1-3) was performed for genotypes inoculated with Azospirillum brasilense. Two commercial single-cross hybrids (AG7098 and 2B707) and two experimental synthetic varieties (V2 and V4) were raised under controlled greenhouse conditions, in six treatment groups corresponding to different forms of inoculation and different levels of nitrogen application by top-dressing. The genotypes presented distinct responses to inoculation with A. brasilense. Increases in the expression of ZmNR were observed for the hybrids, while V4 only displayed a greater level of expression when the plants received nitrogenous fertilization by top-dressing and there was no inoculation. The expression of the ZmGln1-3EST was induced by A. brasilense in the hybrids and the variety V4. In contrast, the variety V2 did not respond to inoculation.

  1. Genomic insights into the versatility of the plant growth-promoting bacterium Azospirillum amazonense

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    Sant'Anna Fernando H

    2011-08-01

    Full Text Available Abstract Background The species Azospirillum amazonense belongs to a well-known genus of plant growth-promoting bacteria. This bacterium is found in association with several crops of economic importance; however, there is a lack of information on its physiology. In this work, we present a comprehensive analysis of the genomic features of this species. Results Genes of A. amazonense related to nitrogen/carbon metabolism, energy production, phytohormone production, transport, quorum sensing, antibiotic resistance, chemotaxis/motility and bacteriophytochrome biosynthesis were identified. Noteworthy genes were the nitrogen fixation genes and the nitrilase gene, which could be directly implicated in plant growth promotion, and the carbon fixation genes, which had previously been poorly investigated in this genus. One important finding was that some A. amazonense genes, like the nitrogenase genes and RubisCO genes, were closer phylogenetically to Rhizobiales members than to species of its own order. Conclusion The species A. amazonense presents a versatile repertoire of genes crucial for its plant-associated lifestyle.

  2. 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.

  3. Seed quality, chlorophyll content index and leaf nitrogen levels in maize inoculated with Azospirillum brasilense

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    Lívia de Matos Pereira

    Full Text Available ABSTRACTThe aim of this study was to evaluate differences between maize genotypes in relation to the germination response of the seeds and the growth of seedlings inoculated with Azospirillum brasilense, as well as the effect of inoculation on nitrogen levels and the chlorophyll content index of the leaves. The physiological seeds quality from the single-cross hybrids AG7098 and 2B707, and from the experimental synthetic varieties V2 and V4, inoculated with A. brasilense, was tested for germination, percentage and rate of emergence, and dry matter weight of the shoots and roots. Nitrogen levels and chlorophyll content index were evaluated in leaves of the same four genotypes grown in a greenhouse under different nitrogen supply systems and methods of inoculation with A. brasilense. The genotypes differ with regard to inoculation with A. brasilense. The hybrids were responsive to inoculation with A. brasilense for root dry matter weight. The V2 variety had a lower performance as regards root dry matter weight, with the opposite being seen for the dry matter weight of the shoots. V4 displayed no significant differences when inoculated. The results of the chlorophyll content index were not significant. Each genotype under evaluation displayed a different response for leaf nitrogen levels. It is possible to infer that the hybrids responded better to inoculation with the bacteria, with the greater root development leading to a better utilisation of water and nutrients.

  4. Characterization of phenylpyruvate decarboxylase, involved in auxin production of Azospirillum brasilense.

    Science.gov (United States)

    Spaepen, Stijn; Versées, Wim; Gocke, Dörte; Pohl, Martina; Steyaert, Jan; Vanderleyden, Jos

    2007-11-01

    Azospirillum brasilense belongs to the plant growth-promoting rhizobacteria with direct growth promotion through the production of the phytohormone indole-3-acetic acid (IAA). A key gene in the production of IAA, annotated as indole-3-pyruvate decarboxylase (ipdC), has been isolated from A. brasilense, and its regulation was reported previously (A. Vande Broek, P. Gysegom, O. Ona, N. Hendrickx, E. Prinsen, J. Van Impe, and J. Vanderleyden, Mol. Plant-Microbe Interact. 18:311-323, 2005). An ipdC-knockout mutant was found to produce only 10% (wt/vol) of the wild-type IAA production level. In this study, the encoded enzyme is characterized via a biochemical and phylogenetic analysis. Therefore, the recombinant enzyme was expressed and purified via heterologous overexpression in Escherichia coli and subsequent affinity chromatography. The molecular mass of the holoenzyme was determined by size-exclusion chromatography, suggesting a tetrameric structure, which is typical for 2-keto acid decarboxylases. The enzyme shows the highest kcat value for phenylpyruvate. Comparing values for the specificity constant kcat/Km, indole-3-pyruvate is converted 10-fold less efficiently, while no activity could be detected with benzoylformate. The enzyme shows pronounced substrate activation with indole-3-pyruvate and some other aromatic substrates, while for phenylpyruvate it appears to obey classical Michaelis-Menten kinetics. Based on these data, we propose a reclassification of the ipdC gene product of A. brasilense as a phenylpyruvate decarboxylase (EC 4.1.1.43).

  5. FTIR and Raman spectroscopic studies of selenium nanoparticles synthesised by the bacterium Azospirillum thiophilum

    Science.gov (United States)

    Tugarova, Anna V.; Mamchenkova, Polina V.; Dyatlova, Yulia A.; Kamnev, Alexander A.

    2018-03-01

    Vibrational (Fourier transform infrared (FTIR) and Raman) spectroscopic techniques can provide unique molecular-level information on the structural and compositional characteristics of complicated biological objects. Thus, their applications in microbiology and related fields are steadily increasing. In this communication, biogenic selenium nanoparticles (Se NPs) were obtained via selenite (SeO32-) reduction by the bacterium Azospirillum thiophilum (strain VKM B-2513) for the first time, using an original methodology for obtaining extracellular NPs. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) showed the Se NPs to have average diameters within 160-250 nm; their zeta potential was measured to be minus 18.5 mV. Transmission FTIR spectra of the Se NPs separated from bacterial cells showed typical proteinacious, polysaccharide and lipid-related bands, in line with TEM data showing a thin layer covering the Se NPs surface. Raman spectra of dried Se NPs layer in the low-frequency region (under 500 cm-1 down to 150 cm-1) showed a single very strong band with a maximum at 250 cm-1 which, in line with its increased width (ca. 30 cm-1 at half intensity), can be attributed to amorphous elementary Se. Thus, a combination of FTIR and Raman spectroscopic approaches is highly informative in non-destructive analysis of structural and compositional properties of biogenic Se NPs.

  6. INOCULACIÓN AL SUELO CON Pseudomonas fluorescens, Azospirillum oryzae, Bacillus subtilis Y MICROORGANISMOS DE MONTAÑA (MM Y SU EFECTO SOBRE UN SISTEMA DE ROTACIÓN SOYA-TOMATE BAJO CONDICIONES DE INVERNADERO

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    Leida Castro Barquero

    2015-01-01

    Full Text Available Se evaluó un sistema de rotación soya- tomate, con incorporación de biomasa verde y aplicación de inóculos microbianos individuales y en mezcla sobre el crecimiento de las plantas y propiedades edáficas; para ello se evaluaron en invernadero por 24 meses los siguientes 9 trata - mientos: solo tomate (T; rotación tomate-soya (TS; rotación tomate-soya con inoculaciones individuales de Azospirillum oryzae (A; de Pseudomonas fluorescens (P; de Bacillus sub - tilis (B; de microorganismos de montaña (MM; y las inoculaciones en mezcla de B. subtilis y P. fluorescens (BP; de B. subtilis, P. fluorescens y A. oryzae ( BPA; d e B. subtilis , P. fluorescens , Azospirillum sp. y MM (BPAMM. Se evalua - ron las variables físicas: densidad aparente y de partículas; conductividad hidráulica; poros totales; estabilidad de agregados; resistencia a la penetración (RP; las variables químicas: pH; conductividad eléctrica; contenido de N y C; relación C/N; contenido de nutrientes en suelos y foliares; las variables biológicas: respiración de suelos, unidades formadoras de colonias de hongos, bacterias y actinomicetos y el peso fres - co y seco foliar. Las variables físicas no fueron afectadas por los tratamientos, con excepción de RP, que fue mayor en el tratamiento T. Las varia - bles biológicas y químicas fueron sensibles a los tratamientos, con valores significativamente más altos en presencia de MM. Destaca el incremento del P en solución de suelo en tratamientos a los que se adicionó MM: pasó de 6 a 20 mg.l -1 ; esta condición se reflejó además en la cantidad de P en el tejido foliar al final del ensayo. Se determi - nó que el pH, CE y la respiración del suelo fueron afectados por la interacción entre los tratamientos aplicados y el tiempo transcurrido; los mayores valores se obtuvieron al final del ensayo y en los tratamientos con MM.

  7. Inoculación al suelo con Pseudomonas fluorescens, Azospirillum oryzae, Bacillus subtilis y microorganismos de montaña (mm y su efecto sobre un sistema de rotación soya-tomate bajo condiciones de invernadero

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    Leida Castro Barquero

    2015-11-01

    Full Text Available Se evaluó un sistema de rotación soyatomate, con incorporación de biomasa verde y aplicación de inóculos microbianos individuales y en mezcla sobre el crecimiento de las plantas y propiedades edáficas; para ello se evaluaron en invernadero por 24 meses los siguientes 9 tratamientos: solo tomate (T; rotación tomate-soya (TS; rotación tomate-soya con inoculaciones individuales de Azospirillum oryzae (A; de Pseudomonas fluorescens (P; de Bacillus subtilis (B; de microorganismos de montaña (MM; y las inoculaciones en mezcla de B. subtilis y P. fluorescens (BP; de B. subtilis, P. fluorescens y A. oryzae (BPA; de B. subtilis, P. fluorescens, Azospirillum sp. y MM (BPAMM. Se evaluaron las variables físicas: densidad aparente y de partículas; conductividad hidráulica; poros totales; estabilidad de agregados; resistencia a la penetración (RP; las variables químicas: pH; conductividad eléctrica; contenido de N y C; relación C/N; contenido de nutrientes en suelos y foliares; las variables biológicas: respiración de suelos, unidades formadoras de colonias de hongos, bacterias y actinomicetos y el peso fresco y seco foliar. Las variables físicas no fueron afectadas por los tratamientos, con excepción de RP, que fue mayor en el tratamiento T. Las variables biológicas y químicas fueron sensibles a los tratamientos, con valores significativamente más altos en presencia de MM. Destaca el incremento del P en solución de suelo en tratamientos a los que se adicionó MM: pasó de 6 a 20 mg.l-1; esta condición se reflejó además en la cantidad de P en el tejido foliar al final del ensayo. Se determinó que el pH, CE y la respiración del suelo fueron afectados por la interacción entre los tratamientos aplicados y el tiempo transcurrido; los mayores valores se obtuvieron al final del ensayo y en los tratamientos con MM.

  8. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Draft genome sequences of six neonatal meningitis-causing escherichia coli isolates (SP-4, SP-5, SP-13, SP-16, SP-46, and SP-65)

    Science.gov (United States)

    Neonatal meningitis Escherichia coli isolates (SP-4, SP-5, SP-13, SP-16, SP-46, and SP-65) were recovered from infants in the Netherlands from 1989 to 1997. Here, we report the draft genome sequences for these six E. coli isolates, which are currently being used to validate food safety processing te...

  10. Azospirillum brasilense Chemotaxis Depends on Two Signaling Pathways Regulating Distinct Motility Parameters.

    Science.gov (United States)

    Mukherjee, Tanmoy; Kumar, Dhivya; Burriss, Nathan; Xie, Zhihong; Alexandre, Gladys

    2016-06-15

    The genomes of most motile bacteria encode two or more chemotaxis (Che) systems, but their functions have been characterized in only a few model systems. Azospirillum brasilense is a motile soil alphaproteobacterium able to colonize the rhizosphere of cereals. In response to an attractant, motile A. brasilense cells transiently increase swimming speed and suppress reversals. The Che1 chemotaxis pathway was previously shown to regulate changes in the swimming speed, but it has a minor role in chemotaxis and root surface colonization. Here, we show that a second chemotaxis system, named Che4, regulates the probability of swimming reversals and is the major signaling pathway for chemotaxis and wheat root surface colonization. Experimental evidence indicates that Che1 and Che4 are functionally linked to coordinate changes in the swimming motility pattern in response to attractants. The effect of Che1 on swimming speed is shown to enhance the aerotactic response of A. brasilense in gradients, likely providing the cells with a competitive advantage in the rhizosphere. Together, the results illustrate a novel mechanism by which motile bacteria utilize two chemotaxis pathways regulating distinct motility parameters to alter movement in gradients and enhance the chemotactic advantage. Chemotaxis provides motile bacteria with a competitive advantage in the colonization of diverse niches and is a function enriched in rhizosphere bacterial communities, with most species possessing at least two chemotaxis systems. Here, we identify the mechanism by which cells may derive a significant chemotactic advantage using two chemotaxis pathways that ultimately regulate distinct motility parameters. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  11. In vitro propagation of fraser photinia using Azospirillum-mediated root development.

    Science.gov (United States)

    Llorente, Berta E; Larraburu, Ezequiel E

    2013-01-01

    Fraser photinia (Photinia × fraseri Dress.) is a woody plant of high ornamental value. The traditional propagation system for photinia is by rooting apical cuttings using highly concentrated auxin treatments. However, photinia micropropagation is an effective alternative to traditional in vivo propagation which is affected by the seasonal supply of cuttings, the long time required to obtain new plants, and the difficulties in rooting some clones.A protocol for in vitro propagation of fraser photinia using the plant growth-promoting ability of some rhizobacteria is described here. Bacterial inoculation is a new tool in micropropagation protocols that improves plant development in in vitro culture. Shoots culture on a medium containing MS macro- and microelements, Gamborg's vitamins (BM), N (6)-benzyladenine (BA, 11.1 μM), and gibberellic acid (1.3 μM) produce well-established explants. Proliferation on BM medium supplemented with 4.4 μM BA results in four times the number of shoots per initial shoot that develops monthly. Consequently, there is a continuous supply of plant material since shoot production is independent of season. Azospirillum brasilense inoculation, after 49.2 μM indole-3-butyric acid pulse treatment, stimulates early rooting of photinia shoots and produces significant increase in root fresh and dry weights, root surface area, and shoot fresh and dry weights in comparison with controls. Furthermore, inoculated in vitro photinia plants show anatomical and morphological changes that might lead to better adaptation in ex vitro conditions after transplanting, compared with the control plants.

  12. 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. Copyright © 2014 Elsevier GmbH. All rights reserved.

  13. Chemical soil attributes after wheat cropping under nitrogen fertilization and inoculation with Azospirillum brasilense

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    Fernando Shintate Galindo

    2017-05-01

    Full Text Available Azospirillum brasilense plays an important role in biological nitrogen fixation (BNF in grasses. However, further studies are needed to define how much mineral N can be applied while simultaneously maintaining BNF contribution and maximizing crop yield and to determine the impact of these practices on soil fertility. Thus, we aimed to investigate the effect of inoculation with A. brasilense, in conjunction with varying N doses and sources in a Cerrado soil, on soil chemical attributes after two years of irrigated wheat production. The experiment was initiated in Selvíria - MS under no-tillage production in an Oxisol in 2014 and 2015. The experimental design was a randomized block design with four replications, and treatments were arranged in a 2 x 5 x 2 factorial arrangement as follows: two N sources (urea and Super N - urea with inhibitor of the enzyme urease NBPT (N - (n-butyl thiophosphoric triamide, five N rates (0, 50, 100, 150 and 200 kg ha-1, and with or without seed inoculation with A. brasilense. The increase in N rates did not influence the chemical soil attributes. Super N acidified the soil more compared to urea. A. brasilense inoculation reduced the effect of soil acidification in intensive irrigated wheat cultivation; however, the base extraction was higher, resulting in a lower soil CEC after cultivation with inoculation. Therefore, the cultivation of wheat inoculated with A. brasilense was not harmful to soil fertility because it did not reduce the base saturation and organic matter content (P, K, Ca, Mg, and S.

  14. 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. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  15. CRECIMIENTO DE Cedrela odorata L. BIOFERTILIZADA CON Rhizophagus intraradices y Azospirillum brasilense EN VIVERO

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    Juan F. Aguirre-Medina

    2014-01-01

    Full Text Available Cedrela odorata L. es una especie que se distingue por la calidad de su madera. El cedro esta - blecido en campo debe adaptarse a cambios en disponibilidad de recursos; la sobrevivivencia es mayor cuando el sistema radical se asocia con microorganismos que mejoran la nutrición y crecimiento. El objetivo del presente trabajo fue evaluar el efecto de Rhizophagus intraradi - ces y Azospirillum brasilense sobre el crecimiento de C. odorata y la capacidad de absorción de nitrógeno (N y fósforo (P. Las semillas de cedro se sembraron en macetas de acuerdo con los siguientes trata - mientos: testigo, fertilización 15 N -15 P -15 K , R. intraradices , A. brasilense , R. intraradices + A. brasilense , y R. intraradices + A. brasilense + fertilización 15 N -15 P -15 K . Las variables morfológicas y fisiológicas de rendimiento y la colonización radical se registraron cada 28 días, y los contenidos de N y P, al final del experimento (140 días. En general, R. intraradices promovió mayor crecimiento vegetal ( P ≤ 0.05 de los componentes morfológicos y fisiológicos del rendimiento. La altura máxima (97 cm se registró en las plantas con R. intraradices + A. brasilense + fertilización 15 N -15 P -15 K , representando 40 % más altura que el testigo. El N y P incrementaron con la inoculación de los microorganismos solos y combinados.

  16. Disruption of dTDP-rhamnose biosynthesis modifies lipopolysaccharide core, exopolysaccharide production, and root colonization in Azospirillum brasilense.

    Science.gov (United States)

    Jofré, Edgardo; Lagares, Antonio; Mori, Gladys

    2004-02-16

    The interaction between Azospirillum brasilense and plants is not fully understood, although several bacterial surface components like exopolysaccharides (EPS), flagella, and capsular polysaccharides are required for attachment and colonization. While in other plant-bacteria associations (Rhizobium-legume, Pseudomonas-potato), lipopolysaccharides (LPS) play a key role in the establishment of an effective association, their role in the root colonization by Azospirillum had not been determined. In this study, we isolated a Tn5 mutant of A. brasilense Cd (EJ1) with an apparently modified LPS core structure, non-mucoid colony morphology, increased EPS production, and affected in maize root colonization. A 3790-bp region revealed the presence of three complete open reading frames designated rmlC, rmlB and rmlD. The beginning of a fourth open reading frame was found and designated rmlA. These genes are organized in a cluster which shows homology to the cluster involved in the synthesis of dTDP-rhamnose in other bacteria. Additionally, the analysis of the monosaccharide composition of LPSs showed a diminution of rhamnose compared to the wild-type strain.

  17. 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 %.

  18. Extracellular polysaccharides are involved in the attachment of Azospirillum brasilense and Rhizobium leguminosarum to arbuscular mycorrhizal structures

    Directory of Open Access Journals (Sweden)

    V Bianciotto

    2009-12-01

    Full Text Available Arbuscular mycorrhizal (AM fungi, one of the most important component of the soil microbial community, establish physical interactions with naturally occurring and genetically modified bacterial biofertilizers and biopesticides, commonly referred to as plant growth-promoting rhizobacteria (PGPR. We have used a genetic approach to investigate the bacterial components possibly involved in the attachment of two PGPR (Azospirillum and Rhizobium to AM roots and AM fungal structures. Mutants affected in extracellular polysaccharides (EPS have been tested in in vitro adhesion assays and shown to be strongly impaired in the attachment to both types of surfaces as well as to quartz fibers. Anchoring of rhizobacteria to AM fungal structures may have special ecological and biotechnological significance because it may facilitate colonisation of new rhizospheres by the bacteria, and may be an essential trait for the development of mixed inocula.

  19. Inoculation effects of Pseudomonas putida, Gluconacetobacter azotocaptans, and Azospirillum lipoferum on corn plant growth under greenhouse conditions.

    Science.gov (United States)

    Mehnaz, Samina; Lazarovits, George

    2006-04-01

    Alcohol production from corn is gaining importance in Ontario, Canada, and elsewhere. A major cost of corn production is the cost of chemical fertilizers and these continue to increase in price. The competitiveness of alcohol with fossil fuels depends on access to low-cost corn that allows growers to earn a sustainable income. In this study we set out to determine if we can identify root-associated microorganisms from Ontario-grown corn that can enhance the nutrient flow to corn roots, directly or indirectly, and help minimize the use of extraneous fertilizer. Bacteria were isolated from corn rhizosphere and screened for their capacity to enhance corn growth. The bacteria were examined for their ability to fix nitrogen, solubilize phosphate, and produce indole acetic acid (IAA) and antifungal substances on potato dextrose agar. Bacterial suspensions were applied to pregerminated seed of four corn varieties (39D82, 39H84, 39M27, and 39T68) planted in sterilized sand and unsterilized cornfield soil. The plants were grown under greenhouse conditions for 30 days. Three isolates were identified as having growth-promoting effect. These bacteria were identified as to species by biochemical tests, fatty acid profiles, and 16S rDNA sequence analysis. Corn rhizosphere isolates, Gluconacetobacter azotocaptans DS1, Pseudomonas putida CQ179, and Azospirillum lipoferum N7, provided significant plant growth promotion expressed as increased root/shoot weight when compared to uninoculated plants, in sand and/or soil. All strains except P. putida CQ179 were capable of nitrogen fixation and IAA production. Azospirillum brasilense, however, produced significantly more IAA than the other isolates. Although several of the strains were also able to solubilize phosphate and produce metabolites inhibitory to various fungal pathogens, these properties are not considered as contributing to growth promotion under the conditions used in this study. These bacteria will undergo field tests for

  20. The celA Gene, Encoding a Glycosyl Hydrolase Family 3 β-Glucosidase in Azospirillum irakense, Is Required for Optimal Growth on Cellobiosides

    Science.gov (United States)

    Faure, Denis; Henrissat, Bernard; Ptacek, David; Bekri, My Ali; Vanderleyden, Jos

    2001-01-01

    The CelA β-glucosidase of Azospirillum irakense, belonging to glycosyl hydrolase family 3 (GHF3), preferentially hydrolyzes cellobiose and releases glucose units from the C3, C4, and C5 oligosaccharides. The growth of a ΔcelA mutant on these cellobiosides was affected. In A. irakense, the GHF3 β-glucosidases appear to be functional alternatives for the GHF1 β-glucosidases in the assimilation of β-glucosides by other bacteria. PMID:11319128

  1. 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.

  2. Enzyme Production and Nitrogen Fixation by Free, Immobilized and Coimmobilized Inoculants of Trichoderma harzianum and Azospirillum brasilense and Their Possible Role in Growth Promotion of Tomato

    Directory of Open Access Journals (Sweden)

    Momein H. El-Katatny

    2010-01-01

    Full Text Available A plant growth-promoting rhizobacterium (Azospirillum brasilense strain Az and a biocontrol fungus (Trichoderma harzianum strain T24 have been evaluated for their individual and combined production of hydrolytic enzymes, nitrogen fixation and their possible role in growth promotion of tomato seedlings. The studied organisms were inoculated as free or calcium alginate-encapsulated cells. All freshly prepared macrobeads showed high encapsulation capacity (EC/% of inocula compared with dry macrobeads. Results of enzyme production did not exhibit consistent pattern of the effect of encapsulation process on enzyme production. Beads entrapping bacterial and/or fungal cells were used successfully in 3 repeated cycles in the presence of fresh sterile culture medium in each growth cycle. Enzyme production by immobilized bacterial and/or fungal cells increased as the growth cycles were repeated. Co-culturing of A. brasilense with T. harzianum (free or immobilized in semisolid nitrogen deficient medium (N-free medium enabled A. brasilense to fix nitrogen on pectin, chitin and carboxymethyl cellulose. The activity of nitrogen fixation by A. brasilense in the case of single and combined cultures with Trichoderma (using dry encapsulated beads into the sterile soil increased with the addition of carbon source. Most of inoculations with free or alginate macrobead formulations of T. harzianum and/or A. brasilense showed significant increase in the growth parameters of tomato seedlings. The root system grew more profusely in the case of all seeds treated with A. brasilense. The growth parameters of Az/T24-treated seeds using dry coimmobilized macrobeads were higher than those of the untreated control. Moreover, the effect was improved significantly in soil enriched with different C sources. Enhanced tomato seedling growth after the co-inoculation could be due to the synergistic effect of both Trichoderma and Azospirillum. Finally, co-inoculation with Azospirillum

  3. Assessment of SCAR markers to design real-time PCR primers for rhizosphere quantification of Azospirillum brasilense phytostimulatory inoculants of maize.

    Science.gov (United States)

    Couillerot, O; Poirier, M-A; Prigent-Combaret, C; Mavingui, P; Caballero-Mellado, J; Moënne-Loccoz, Y

    2010-08-01

    To assess the applicability of sequence characterized amplified region (SCAR) markers obtained from BOX, ERIC and RAPD fragments to design primers for real-time PCR quantification of the phytostimulatory maize inoculants Azospirillum brasilense UAP-154 and CFN-535 in the rhizosphere. Primers were designed based on strain-specific SCAR markers and were screened for successful amplification of target strain and absence of cross-reaction with other Azospirillum strains. The specificity of primers thus selected was verified under real-time PCR conditions using genomic DNA from strain collection and DNA from rhizosphere samples. The detection limit was 60 fg DNA with pure cultures and 4 x 10(3) (for UAP-154) and 4 x 10(4) CFU g(-1) (for CFN-535) in the maize rhizosphere. Inoculant quantification was effective from 10(4) to 10(8) CFU g(-1) soil. BOX-based SCAR markers were useful to find primers for strain-specific real-time PCR quantification of each A. brasilense inoculant in the maize rhizosphere. Effective root colonization is a prerequisite for successful Azospirillum phytostimulation, but cultivation-independent monitoring methods were lacking. The real-time PCR methods developed here will help understand the effect of environmental conditions on root colonization and phytostimulation by A. brasilense UAP-154 and CFN-535.

  4. Phytohormones and induction of plant-stress tolerance and defense genes by seed and foliar inoculation with Azospirillum brasilense cells and metabolites promote maize growth.

    Science.gov (United States)

    Fukami, Josiane; Ollero, Francisco Javier; Megías, Manuel; Hungria, Mariangela

    2017-12-01

    Azospirillum spp. are plant-growth-promoting bacteria used worldwide as inoculants for a variety of crops. Among the beneficial mechanisms associated with Azospirillum inoculation, emphasis has been given to the biological nitrogen fixation process and to the synthesis of phytohormones. In Brazil, the application of inoculants containing A. brasilense strains Ab-V5 and Ab-V6 to cereals is exponentially growing and in this study we investigated the effects of maize inoculation with these two strains applied on seeds or by leaf spray at the V2.5 stage growth-a strategy to relieve incompatibility with pesticides used for seed treatment. We also investigate the effects of spraying the metabolites of these two strains at V2.5. Maize growth was promoted by the inoculation of bacteria and their metabolites. When applied via foliar spray, although A. brasilense survival on leaves was confirmed by confocal microscopy and cell recovery, few cells were detected after 24 h, indicating that the effects of bacterial leaf spray might also be related to their metabolites. The major molecules detected in the supernatants of both strains were indole-3-acetic acid, indole-3-ethanol, indole-3-lactic acid and salicylic acid. RT-PCR of genes related to oxidative stress (APX1, APX2, CAT1, SOD2, SOD4) and plant defense (pathogenesis-related PR1, prp2 and prp4) was evaluated on maize leaves and roots. Differences were observed according to the gene, plant tissue, strain and method of application, but, in general, inoculation with Azospirillum resulted in up-regulation of oxidative stress genes in leaves and down-regulation in roots; contrarily, in general, PR genes were down-regulated in leaves and up-regulated in roots. Emphasis should be given to the application of metabolites, especially of Ab-V5 + Ab-V6 that in general resulted in the highest up-regulation of oxidative-stress and PR genes both in leaves and in roots. We hypothesize that the benefits of inoculation of Azospirillum on

  5. ExaSP2

    Energy Technology Data Exchange (ETDEWEB)

    2017-09-08

    ExaSP2 is a reference implementation of typical linear algebra algorithms and workloads for a quantum molecular dynamics (QMD) electronic structure code. The algorithm is based on a recursive second-order Fermi-Operator expansion method (SP2) and is tailored for density functional based tight-binding calculations of material systems.

  6. 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.

  7. Caracterización de bacterias diazotróficas asimbióticas asociadas al eucalipto (eucalyptus sp.) en codazzi, cesar.

    OpenAIRE

    Obando Castellanos, Dolly Melissa; Burgos Zabala, Ludy Beatriz; Rivera Botía, Diego Mauricio; Rubiano Garrido, María Fernanda; Bonilla Buitrago, Ruth Rebeca; Divan Baldani, Vera Lúcia

    2010-01-01

    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 nitr...

  8. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. 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. Copyright © 2012. Published by Elsevier Inc.

  11. 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. Copyright © 2012. Published by Elsevier Inc.

  12. Fuzzy SP-irresolute functions

    International Nuclear Information System (INIS)

    Abbas, S.E.

    2004-01-01

    In this paper, fuzzy SP-irresolute, fuzzy SP-irresolute open and fuzzy SP-irresolute closed functions between fuzzy topological spaces in Sostak sense are defined. Their properties and the relationships between these functions and other functions introduced previously are investigated. Next fuzzy SP-connectedness is introduced and studied with the help of r-fuzzy strongly preopen sets

  13. 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. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  14. 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

  15. 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

    Directory of Open Access Journals (Sweden)

    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

  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. 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. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. 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.

    2012-01-01

    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. PMID:22522896

  20. 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.

    2012-01-01

    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 σ54 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. PMID:22267004

  1. 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. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  2. 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.

  3. 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.

  4. 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.

  5. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Effect of seed inoculation with Azospirillum brasilense and nitrogen fertilization rates on maize plant yield and silage quality

    Directory of Open Access Journals (Sweden)

    Fernando Reimann Skonieski

    Full Text Available ABSTRACT The objective of this study was to determine the effect of Azospirillum brasilense inoculation and different nitrogen (N rates applied as topdressing on the productivity of a maize crop and the nutritional value of maize silage. Two experiments were conducted in the 2012/2013 and 2013/2014 harvests. Treatments were distributed in a randomized block design in a factorial arrangement, which consisted of two maize hybrids (AS 1572 and Defender coupled with nitrogen rates (0, 60, 120, 240, and 480 kg ha-1, inoculated or uninoculated with A. brasilense. Inoculated seeds were treated with the A. brasilense strains Ab-V5 and Ab-V6. Inoculation with A. brasilense showed interaction with the hybrids, agricultural years, and nitrogen rates for the maize plant yield. In the 2012/2013 agricultural year, inoculation increased the AS 1572 hybrid silage yield by 6.16% and, in the 2013/2014 harvest, A. brasilense inoculation produced an increase of 16.15% for the Defender hybrid. Nitrogen fertilization applied at 0, 60, and 120 kg ha-1 N benefited the plants inoculated with A. brasilense. The statistical equations revealed that N rates between 0 and 184 kg ha-1 in A. brasilense inoculated plants raised the plant productivity for silage when compared with the control plants. Regarding the nutritional value of the silage, inoculation with A. brasilense increased the ether extract levels and total digestible nutrients and reduced the amount of acid detergent fiber. For all this, positive results with inoculation for silage yield are dependent on nitrogen fertilization rate. Inoculation with A. brasilense can promote changes in the maize silage quality, but with obtained results it is not possible to definitely conclude upon nutritive value of maize silage.

  7. Revealing strategies of quorum sensing in Azospirillum brasilense strains Ab-V5 and Ab-V6.

    Science.gov (United States)

    Fukami, Josiane; Abrantes, Julia Laura Fernandes; Del Cerro, Pablo; Nogueira, Marco Antonio; Ollero, Francisco Javier; Megías, Manuel; Hungria, Mariangela

    2018-01-01

    Azospirillum brasilense is an important plant-growth promoting bacterium (PGPB) that requires several critical steps for root colonization, including biofilm and exopolysaccharide (EPS) synthesis and cell motility. In several bacteria these mechanisms are mediated by quorum sensing (QS) systems that regulate the expression of specific genes mediated by the autoinducers N-acyl-homoserine lactones (AHLs). We investigated QS mechanisms in strains Ab-V5 and Ab-V6 of A. brasilense, which are broadly used in commercial inoculants in Brazil. Neither of these strains carries a luxI gene, but there are several luxR solos that might perceive AHL molecules. By adding external AHLs we verified that biofilm and EPS production and cell motility (swimming and swarming) were regulated via QS in Ab-V5, but not in Ab-V6. Differences were observed not only between strains, but also in the specificity of LuxR-type receptors to AHL molecules. However, Ab-V6 was outstanding in indole acetic acid (IAA) synthesis and this molecule might mimic AHL signals. We also applied the quorum quenching (QQ) strategy, obtaining transconjugants of Ab-V5 and Ab-V6 carrying a plasmid with acyl-homoserine lactonase. When maize (Zea mays L.) was inoculated with the wild-type and transconjugant strains, plant growth was decreased with the transconjugant of Ab-V5-confirming the importance of an AHL-mediated QS system-but did not affect plant growth promotion by Ab-V6.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Eficiência da inoculação de Azospirillum brasilense associado com enraizador no crescimento e na produção de alface

    Directory of Open Access Journals (Sweden)

    Antonio Anicete de Lima

    2017-06-01

    Full Text Available Objetivou-se avaliar o efeito da inoculação de Azospirillum brasilense (AzBr com e sem enraizador, no crescimento, produção de biomassa e resistência a pragas da alface, cultivar Lucy Brown. O experimento foi conduzido em casa de vegetação em recipientes plásticos com capacidade de 8,0 L no espaçamento 40 x 20 cm. O delineamento experimental foi de blocos casualizados em esquema fatorial (2x3+1, sendo o primeiro fator Azospirillum com e sem enraizador de crescimento e o segundo doses de nitrogênio em cobertura, 0%, 50% e 100% da recomendação de adubação e uma testemunha com adubação convencional, com quatro repetições. Em doses médias de 50% de N em cobertura, tanto o AzBr, quanto a associação AzBr mais enraizador, apresentaram um incremento significativo na massa fresca da parte aérea e de raízes de 19,36% e 23,66%, respectivamente, em relação a dose máxima de N e a testemunha. A massa seca da parte aérea não diferiu significativamente nos diferentes tratamentos, embora tenha mostrado um pequeno aumento com as doses crescente de N. A massa seca de raízes diminuiu 29,24% no tratamento com 100% de N, quando comparado ao tratamento sem cobertura nitrogenada mais AzBr. O estande final de plantas foi significativamente maior no tratamento no qual N não foi aplicado em cobertura, destacando-se a inoculação com AzBr, média de 96,98% de plantas estabelecidas, contra 51,56% na testemunha convencional, observando-se que até a dose média de N, houve uma maior tolerância das plantas aos sintomas de minas foliares e as viroses do Grupo Tospovirus.Azospirillum brasilense inoculation efficiency associated with rooting growth and production of lettuceAbstract: In the survey evaluated the effect of Azospirillum brasilense (AzBr inoculated with and without rooting, on growth, biomass production and lettuce pest resistance, cultivar Lucy Brown. The experiment was conducted in a greenhouse in plastic bags with 8.0 L capacity in

  10. Cryptosporidium sp. in lizards

    Czech Academy of Sciences Publication Activity Database

    Koudela, Břetislav; Modrý, D.

    1998-01-01

    Roč. 45, č. 1 (1998), s. 8 ISSN 1066-5234. [ Cryptosporidium sp. in lazards. 01.01.1998-02.01.1998, Praha] R&D Projects: GA ČR GA508/95/0273; GA AV ČR IPP2020702 Subject RIV: fp - Other Medical Disciplines

  11. 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

  12. Maize Inoculation with Azospirillum brasilense Ab-V5 Cells Enriched with Exopolysaccharides and Polyhydroxybutyrate Results in High Productivity under Low N Fertilizer Input

    Science.gov (United States)

    Oliveira, André L. M.; Santos, Odair J. A. P.; Marcelino, Paulo R. F.; Milani, Karina M. L.; Zuluaga, Mónica Y. A.; Zucareli, Claudemir; Gonçalves, Leandro S. A.

    2017-01-01

    Although Azospirillum strains used in commercial inoculant formulations presents diazotrophic activity, it has been reported that their ability to produce phytohormones plays a pivotal role in plant growth-promotion, leading to a general recommendation of its use in association with regular N-fertilizer doses. In addition, a high variability in the effectiveness of Azospirillum inoculants is still reported under field conditions, contributing to the adoption of the inoculation technology as an additional management practice rather than its use as an alternative practice to the use of chemical inputs in agriculture. To investigate whether the content of stress-resistance biopolymers would improve the viability and performance of Azospirillum inoculants when used as substitute of N-fertilizers, biomass of A. brasilense strain Ab-V5 enriched in exopolysaccharides (EPS) and polyhydroxybutirate (PHB) was produced using a new culture medium developed by factorial mixture design, and the effectiveness of resulting inoculants was evaluated under field conditions. The culture medium formulation extended the log phase of A. brasilense cultures, which presented higher cell counts and increased EPS and PHB contents than observed in the cultures grown in the OAB medium used as control. An inoculation trial with maize conducted under greenhouse conditions and using the biopolymers-enriched Ab-V5 cells demonstrated the importance of EPS and PHB to the long term bacterial viability in soil and to the effectiveness of inoculation. The effectiveness of liquid and peat inoculants prepared with Ab-V5 cells enriched with EPS and PHB was also evaluated under field conditions, using maize as target crop along different seasons, with the inoculants applied directly over seeds or at topdressing under limiting levels of N-fertilization. No additive effect on yield resulted from inoculation under high N fertilizer input, while inoculated plants grown under 80% reduction in N fertilizer

  13. Maize Inoculation withAzospirillum brasilenseAb-V5 Cells Enriched with Exopolysaccharides and Polyhydroxybutyrate Results in High Productivity under Low N Fertilizer Input.

    Science.gov (United States)

    Oliveira, André L M; Santos, Odair J A P; Marcelino, Paulo R F; Milani, Karina M L; Zuluaga, Mónica Y A; Zucareli, Claudemir; Gonçalves, Leandro S A

    2017-01-01

    Although Azospirillum strains used in commercial inoculant formulations presents diazotrophic activity, it has been reported that their ability to produce phytohormones plays a pivotal role in plant growth-promotion, leading to a general recommendation of its use in association with regular N-fertilizer doses. In addition, a high variability in the effectiveness of Azospirillum inoculants is still reported under field conditions, contributing to the adoption of the inoculation technology as an additional management practice rather than its use as an alternative practice to the use of chemical inputs in agriculture. To investigate whether the content of stress-resistance biopolymers would improve the viability and performance of Azospirillum inoculants when used as substitute of N-fertilizers, biomass of A. brasilense strain Ab-V5 enriched in exopolysaccharides (EPS) and polyhydroxybutirate (PHB) was produced using a new culture medium developed by factorial mixture design, and the effectiveness of resulting inoculants was evaluated under field conditions. The culture medium formulation extended the log phase of A. brasilense cultures, which presented higher cell counts and increased EPS and PHB contents than observed in the cultures grown in the OAB medium used as control. An inoculation trial with maize conducted under greenhouse conditions and using the biopolymers-enriched Ab-V5 cells demonstrated the importance of EPS and PHB to the long term bacterial viability in soil and to the effectiveness of inoculation. The effectiveness of liquid and peat inoculants prepared with Ab-V5 cells enriched with EPS and PHB was also evaluated under field conditions, using maize as target crop along different seasons, with the inoculants applied directly over seeds or at topdressing under limiting levels of N-fertilization. No additive effect on yield resulted from inoculation under high N fertilizer input, while inoculated plants grown under 80% reduction in N fertilizer

  14. Effect of Nitrogen and Zinc Sulphate Fertilizers and Azotobacter and Azospirillum Biofertilizer on Yield and Growth Traits of Rapeseed (Brassica napus L.

    Directory of Open Access Journals (Sweden)

    N. Jafari

    2013-06-01

    Full Text Available In order to study the effects of simultaneous application of nitrogen (N and ZnSO4 fertilizers and biofertilizer (Azotobacter and Azospirillum on grain yield and growth traits of rapeseed, Hyola308 cultivar, a field experiment, with split plot factorial layout based on randomized complete blocks design with three replications, was conducted at Research Field of Faculty of Agriculture, University of Guilan, Rasht, Iran, during 2007-2008 growing season. Nitrogen fertilizer at four levels (0, 50, 100 and 150 kg/ha were the main plot and ZnSO4 fertilizer at two levels (0 and 50 kg/ha and biofertilizer at two levels (with and without biofertilizer were arranged in sub-plots. Results showed that maximum and minimum leaf area indices at flowering stage (average of 1.29 and 0.95, respectively were obtained in 150 kg/ha N+ZnSO4+ biofertilizer and in 50 kg/ha N+ no ZnSO4+ no biofertilizer treatments. Maximum and minimum crop growth rates at flowering stage (average of 5.89 and 3.19 g/m2.GDD, respectively were obtained in 150 kg/ha N+ZnSO4+ biofertilizer and control treatments. Maximum and minimum grain yields (2568, 2468 and 543 kg/ha, respectively were obtained in 150 kg/ha N+ with/without ZnSO4+ biofertilizer and control (no fertilizer treatments. Maximum and minimum oil yields (42.8 and 37.3%, respectively were measured in 0 kg/ha N+ZnSO4+ biofertilizer and 150 kg/ha N+ no ZnSO4+ no biofertilizer treatments. Since there was no significant difference between 150 and 100 kg/ha N+ZnSO4+ biofertilizer treatments in terms of impact on canola grain yield and growth traits, it seems that application of biofertilizer (Azotobacter and Azospirillum, without any reduction in yield, increased grain production and oil content and saved 50 kg/ha of N fertilizer. Biofertilizer (Azotobacter and Azospirillum, along with zinc and sulfur, produced phytohormones, and N fertilizer increased dry matter accumulation and leaf area index (by increasing carbohydrate conversion

  15. Maize Inoculation with Azospirillum brasilense Ab-V5 Cells Enriched with Exopolysaccharides and Polyhydroxybutyrate Results in High Productivity under Low N Fertilizer Input

    Directory of Open Access Journals (Sweden)

    André L. M. Oliveira

    2017-09-01

    Full Text Available Although Azospirillum strains used in commercial inoculant formulations presents diazotrophic activity, it has been reported that their ability to produce phytohormones plays a pivotal role in plant growth-promotion, leading to a general recommendation of its use in association with regular N-fertilizer doses. In addition, a high variability in the effectiveness of Azospirillum inoculants is still reported under field conditions, contributing to the adoption of the inoculation technology as an additional management practice rather than its use as an alternative practice to the use of chemical inputs in agriculture. To investigate whether the content of stress-resistance biopolymers would improve the viability and performance of Azospirillum inoculants when used as substitute of N-fertilizers, biomass of A. brasilense strain Ab-V5 enriched in exopolysaccharides (EPS and polyhydroxybutirate (PHB was produced using a new culture medium developed by factorial mixture design, and the effectiveness of resulting inoculants was evaluated under field conditions. The culture medium formulation extended the log phase of A. brasilense cultures, which presented higher cell counts and increased EPS and PHB contents than observed in the cultures grown in the OAB medium used as control. An inoculation trial with maize conducted under greenhouse conditions and using the biopolymers-enriched Ab-V5 cells demonstrated the importance of EPS and PHB to the long term bacterial viability in soil and to the effectiveness of inoculation. The effectiveness of liquid and peat inoculants prepared with Ab-V5 cells enriched with EPS and PHB was also evaluated under field conditions, using maize as target crop along different seasons, with the inoculants applied directly over seeds or at topdressing under limiting levels of N-fertilization. No additive effect on yield resulted from inoculation under high N fertilizer input, while inoculated plants grown under 80% reduction in

  16. Tsukamurella inchonensis sp. nov.

    Science.gov (United States)

    Yassin, A F; Rainey, F A; Brzezinka, H; Burghardt, J; Lee, H J; Schaal, K P

    1995-07-01

    Chemotaxonomic and genomic 16S ribosomal DNA sequence analyses of two isolates obtained from two different clinical materials clearly delineated a new species of the genus Tsukamurella. This new species can be identified by its 16S ribosomal DNA similarity values, as well as its physiological characteristics. The name Tsukamurella inchonensis sp. nov. is proposed for these isolates, which are represented by strain IMMIB D-771T (= DSM 44067T) (T = type strain). This strain exhibits only 45% DNA relatedness to Tsukamurella paurometabola.

  17. SP-100 surety evaluation

    International Nuclear Information System (INIS)

    1985-06-01

    This report describes surety evaluations conducted during GFY 1985 in support of the General Electric design for a Space Nuclear Power System - SP-100. Those surety evaluations address both safety and safeguards requirements, which are derived from OSNP-1 and supporting documents. The report includes results of neutronics (criticality) calculations performed by Los Alamos. The results have been benchmarked against independent calculations performed by General Electric with different codes. These comparisons show close agreement, and are summarized. Los Alamos has also provided specifications of explosion and fire environments, which have been used in evaluation of the GE SP-100 concept. Following the summary of key results, surety requirements are given and recommendations toward specification of requirements for later SP-100 project phases are presented. A conceptual design summary is presented. To establish a comprehensive background for surety evaluations, a reference mission profile and potential accidents for each phase of the mission are identified. The main body of the report addresses surety of the General Electric Thermoelectric Conversion design. GE has also developed a Stirling Engine concept, and performed comprehensive surety evaluations for it. These evaluations are reported

  18. Azospirillum and arbuscular mycorrhizal colonization enhance rice growth and physiological traits under well-watered and drought conditions.

    Science.gov (United States)

    Ruíz-Sánchez, Michel; Armada, Elisabet; Muñoz, Yaumara; García de Salamone, Inés E; Aroca, Ricardo; Ruíz-Lozano, Juan Manuel; Azcón, Rosario

    2011-07-01

    The response of rice plants to inoculation with an arbuscular mycorrhizal (AM) fungus, Azospirillum brasilense, or combination of both microorganisms, was assayed under well-watered or drought stress conditions. Water deficit treatment was imposed by reducing the amount of water added, but AM plants, with a significantly higher biomass, received the same amount of water as non-AM plants, with a poor biomass. Thus, the water stress treatment was more severe for AM plants than for non-AM plants. The results showed that AM colonization significantly enhanced rice growth under both water conditions, although the greatest rice development was reached in plants dually inoculated under well-watered conditions. Water level did not affect the efficiency of photosystem II, but both AM and A. brasilense inoculations increased this value. AM colonization increased stomatal conductance, particularly when associated with A. brasilense, which enhanced this parameter by 80% under drought conditions and by 35% under well-watered conditions as compared to single AM plants. Exposure of AM rice to drought stress decreased the high levels of glutathione that AM plants exhibited under well-watered conditions, while drought had no effect on the ascorbate content. The decrease of glutathione content in AM plants under drought stress conditions led to enhance lipid peroxidation. On the other hand, inoculation with the AM fungus itself increased ascorbate and proline as protective compounds to cope with the harmful effects of water limitation. Inoculation with A. brasilense also enhanced ascorbate accumulation, reaching a similar level as in AM plants. These results showed that, in spite of the fact that drought stress imposed by AM treatments was considerably more severe than non-AM treatments, rice plants benefited not only from the AM symbiosis but also from A. brasilense root colonization, regardless of the watering level. However, the beneficial effects of A. brasilense on most of the

  19. 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

  20. Elucidation of a masked repeating structure of the O-specific polysaccharide of the halotolerant soil bacteria Azospirillum halopraeferens Au4

    Directory of Open Access Journals (Sweden)

    Elena N. Sigida

    2016-04-01

    Full Text Available An O-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide isolated by the phenol–water extraction from the halotolerant soil bacteria Azospirillum halopraeferens type strain Au4. The polysaccharide was studied by sugar and methylation analyses, selective cleavages by Smith degradation and solvolysis with trifluoroacetic acid, one- and two-dimensional 1H and 13C NMR spectroscopy. The following masked repeating structure of the O-specific polysaccharide was established: →3-α-L-Rhap2Me-(1→3-[β-D-Glcp-(1→4]-α-D-Fucp-(1→2-β-D-Xylp-(1→, where non-stoichiometric substituents, an O-methyl group (~45% and a side-chain glucose residue (~65%, are shown in italics.

  1. 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.

  2. 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.

  3. Increased Growth of the Microalga Chlorella vulgaris when Coimmobilized and Cocultured in Alginate Beads with the Plant-Growth-Promoting Bacterium Azospirillum brasilense†

    Science.gov (United States)

    Gonzalez, Luz E.; Bashan, Yoav

    2000-01-01

    Coimmobilization of the freshwater microalga Chlorella vulgaris and the plant-growth-promoting bacterium Azospirillum brasilense in small alginate beads resulted in a significantly increased growth of the microalga. Dry and fresh weight, total number of cells, size of the microalgal clusters (colonies) within the bead, number of microalgal cells per cluster, and the levels of microalgal pigments significantly increased. Light microscopy revealed that both microorganisms colonized the same cavities inside the beads, though the microalgae tended to concentrate in the more aerated periphery while the bacteria colonized the entire bead. The effect of indole-3-acetic acid addition to microalgal culture prior to immobilization of microorganisms in alginate beads partially imitated the effect of A. brasilense. We propose that coimmobilization of microalgae and plant-growth-promoting bacteria is an effective means of increasing microalgal populations within confined environments. PMID:10742237

  4. 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

  5. Polihidroxialcanoatos de cepas de Azospirillum spp. aisladas de raíces de Lycopersicon esculentum Mill. “tomate” y Oryza sativa L. “arroz” en Lambayeque

    Directory of Open Access Journals (Sweden)

    Katty Baca

    2010-01-01

    Full Text Available En este trabajo se determinó la concentración de polihidroxialcanoatos (PH As de cepas de Azospirillum aisladas de raíces de Lycopersicon esculentum Mill. “tomate” y Oryza sativa L. “arroz”, como una alternativa ante la acumulación de plásticos derivados del petróleo. R aíces previamente desinfectadas se sembraron en medio Nfb se misólido, donde las bacterias fijadoras de nitrógeno se reconocieron por una película blanquecina bajo la superficie y el viraje del indicador al azul. El género Azospirillum se identificó en medio rojo de Congo, obteniéndose 96 cepas de A. lipoferum y A. brasilense en tomate y arroz. Se realizó una fermentación discontinua con caldo Azotobacter modificado, alimentando con una solución saturada de ácido málico cada 12 horas y se realizaron tinciones con Sudán Negro B. Se seleccionaron las cepas con mayor nú mero de gránulos de PHAs (en tomate , 18 de A. lipoferum y 2 de A. brasilense y en arroz, 10 de A. lipoferum y 10 de A. brasilense y se cuantificó la biomasa y PHAs. La concentración de PHAs alcanzó 0 . 661 gL - 1 en A. lipoferum KM(T - 73 y 0 . 738 gL - 1 en A. br asilense KM(T - 19. Las cepas de A. lipoferum y A. brasilense aisladas de tomate alcanzaron una mayor concentración de biomasa y PHAs frente a las cepas aisladas de arroz.

  6. Tsukamurella pulmonis sp. nov.

    Science.gov (United States)

    Yassin, A F; Rainey, F A; Brzezinka, H; Burghardt, J; Rifai, M; Seifert, P; Feldmann, K; Schaal, K P

    1996-04-01

    Chemotaxonomic and 16S ribosomal DNA sequence analyses of an isolate from the sputum of a patient with a mycobacterial lung infection clearly delineated a new species of the genus Tsukamurella. This new species can be defined on the basis of genotypic and phenotypic data. The name Tsukamurella pulmonis sp. nov. is proposed for this organism; the type strain is IMMIB D-1321T (= DSM 44142T). This isolate shows 44.2 and 36.2% DNA relatedness to Tsukamurella paurometabola DSM 20162T (T = type strain) and Tsukamurella inchonensis DSM 44067T, respectively.

  7. Acetobacter intermedius, sp. nov.

    Science.gov (United States)

    Boesch, C; Trcek, J; Sievers, M; Teuber, M

    1998-03-01

    Strains of a new species in the genus Acetobacter, for which we propose the name A. intermedius sp. nov., were isolated and characterized in pure culture from different sources (Kombucha beverage, cider vinegar, spirit vinegar) and different countries (Switzerland, Slovenia). The isolated strains grow in media with 3% acetic acid and 3% ethanol as does A. europaeus, do, however, not require acetic acid for growth. These characteristics phenotypically position A. intermedius between A. europaeus and A. xylinus, DNA-DNA hybridizations of A. intermedius-DNA with DNA of the type strains of Acetobacter europaeus, A. xylinus, A. aceti, A. hansenii, A. liquefaciens, A. methanolicus, A. pasteurianus, A. diazotrophicus, Gluconobacter oxydans and Escherichia coli HB 101 indicated less than 60% DNA similarity. The important features of the new species are described. Acetobacter intermedius strain TF2 (DSM11804) isolated from the liquid phase of a tea fungus beverage (Kombucha) is the type strain.

  8. Tsukamurella tyrosinosolvens sp. nov.

    Science.gov (United States)

    Yassin, A F; Rainey, F A; Burghardt, J; Brzezinka, H; Schmitt, S; Seifert, P; Zimmermann, O; Mauch, H; Gierth, D; Lux, I; Schaal, K P

    1997-07-01

    Chemotaxonomic and 16S ribosomal DNA sequence analyses of four bacterial isolates from blood cultures from patients with cardiac pacemaker implants and sputa of patients with chronic lung infections clearly demonstrated that these bacteria belong to the genus Tsukamurella. DNA-DNA hybridization data, as well as the physiological characteristics of the isolates, indicate that they are closely related and belong to a single species that differs from previously described members of the genus Tsukamurella. The name Tsukamurella tyrosinosolvens sp. nov. is proposed for these isolates, and the new species is represented by strain IMMIB D-1397T (= DSM 44234T). Strain IMMIB D-1397T exhibits 53.4, 53.5, and 54.7% DNA-DNA relatedness to Tsukamurella paurometabola DSM 20162T, Tsukamurella inchonensis DSM 44067T, and Tsukamurella pulmonis DSM 44142T, respectively.

  9. USSR Report, Life Sciences Biomedical and Behavioral Sciences

    Science.gov (United States)

    1984-06-04

    wheat Saratovskaya-52 as a lectin preparation. Interaction of wheat lectin with Azospirillum brasilense Sp 7, Spirillum azotocolligens 129 and...microorganisms studied. The high agglutination level during interaction of wheat lectin with Azospirillum brasilense, an associative microorganism for

  10. 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

  11. 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.

  12. SP-100 reactor design

    International Nuclear Information System (INIS)

    Armijo, J.S.; Atwell, J.; Pluta, P.R.; Smith, M.A.; Solorzano, E.R.

    1987-01-01

    The SP-100 space reactor power system is being designed and developed as part of the Ground Engineering System (GES) contract between General Electric Company as the system developer and the Department of Energy. Other key participants in the GES program include Westinghouse Hanford Company (site operator), Los Alamos National Laboratory (fuel development and production), Oak Ridge National Laboratory (materials), and Westinghouse, Advanced Energy Systems Division (shield, HTS equipment). The GES Program includes two major elements. First, the development of a Reference Flight System design at 100 kWe output to the user, and second the validation of the Reference Flight System design by analysis and by testing. Development of key technologies along with component and system testing is an essential part of the validation program. The nuclear subsystem validation includes the design, manufacture, assembly and operational testing of a Ground Reactor Test Assembly. The subject of this paper is the reactor design for the Reference Flight System. The reference flight design is in the preliminary design stage and will evolve over the next year

  13. The effect of plant growth promoting rhizobacteria (PGPR on quantitative and qualitative characteristics of Sesamum indicum L. with application of cover crops of Lathyrus sp. and Persian clover (Trifolium resopinatum L.

    Directory of Open Access Journals (Sweden)

    M. Jahan

    2016-05-01

    Full Text Available Cover crops cultivation and application of plant growth rhizobacteria are the key factors to enhance agroecosystem health. A field experiment was conducted at the Research Farm of Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, during growing season of 2009-2010. A split plot arrangement based on a complete randomized block design with three replications was used. Cultivation and no cultivation of Lathyrus sp. and Persian clover (Trifolium resopinatum in autumn assigned to the main plots. The sub plot factor consisted of three different types of biofertilizers plus control, including 1-nitroxin (containing of Azotobacter sp. and Azospirillum sp., 2- phosphate solubilizing bacteria (PSB (containing of Bacillus sp. and Pseudomonas sp., 3- biosulfur (containing of Thiobacillus ssp. and 4- control (no fertilizer. The results showed the effect of cover crops on seed number and seed weight per plant, biological and seed yield was significant, as the seed yield increased of 9 %. In general, biofertilizers showed superiority due to the most studied traits compared to control. Nitroxin, PSB and biosulfur increased biological yield of 44, 28 and 26 % compared to control, respectively. Cover crops and biofertilizers interactions, showed significant effect on all studied traits, as the highest and the lowest harvest index resulted in cover crop combined with biofertilizers (22.1% and cultivation and no cultivation of cover crops combined with control (15.3%, respectively. The highest seed oil and protein content resulted from cover crops plus biofertilizers (42.4% and cover crops plus PSB (22.5%, respectively. In general, the results showed cover crops cultivation in combination with biofertilizers application could be an ecological alternative for chemical fertilizers, in addition of achieving advantages of cover crops. According to the results, it should be possible to design an ecological cropping system and produce appropriate and healthy

  14. EFECT OF THE INOCULATION OF Rhodococcus fascians AND Azospirillum halopraeferens IN GERMINATION OF PALO FIERRO (Olneya tesota A. Gray UNDER GREENHOUSE CONDITIONS

    Directory of Open Access Journals (Sweden)

    Edgar Omar Rueda Puente

    2017-05-01

    Full Text Available The growth-promoting bacteria in plants (BGPB are a group of different species of bacteria can increase plant growth and productivity. Which can benefit plants through their own bacterial metabolism (phosphate solubilizing, producing hormones or fixing nitrogen. At present, desertification is a growing phenomenon worldwide, afforestation is one of the common solutions to combat this problem. Trees for reforestation are initially grown in greenhouses or nurseries. Among numerous reforestation practices, there is an alternative that inoculation with PGPB. Is a forest species that is endemic Olneya tesota Sonoran Desert, which is in danger of extinction. The objective was to evaluate the effect of bacteria growth promoter in plants with Rhodococcuis fascians and Azospirillum halopraeferens on germination and emergence of Ironwood under four salt concentrations (0, 0.25, 0.5 and 0.75 M NaCl under greenhouse conditions. Were obtained ironwood seeds in the region of Santa Ana, Sonora. Under greenhouse conditions was evaluated emergence percentage, germination rate, height, plant root length, fresh and dry weight of plant, number of bacterial cells attached to the root system, fresh and dry weight of the root. The results indicate that the germination percentage and other variables evaluated decreased as salinity increases. However, these changed positively to inoculation with bacteria R. fascians and A. halopraeferens.

  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. Enhanced performance of the microalga Chlorella sorokiniana remotely induced by the plant growth-promoting bacteria Azospirillum brasilense and Bacillus pumilus

    Science.gov (United States)

    Amavizca, Edgar; Bashan, Yoav; Ryu, Choong-Min; Farag, Mohamed A.; Bebout, Brad M.; de-Bashan, Luz E.

    2017-01-01

    Remote effects (occurring without physical contact) of two plant growth-promoting bacteria (PGPB) Azospirillum brasilense Cd and Bacilus pumilus ES4 on growth of the green microalga Chlorella sorokiniana UTEX 2714 were studied. The two PGPB remotely enhanced the growth of the microalga, up to six-fold, and its cell volume by about three-fold. In addition to phenotypic changes, both bacteria remotely induced increases in the amounts of total lipids, total carbohydrates, and chlorophyll a in the cells of the microalga, indicating an alteration of the microalga’s physiology. The two bacteria produced large amounts of volatile compounds, including CO2, and the known plant growth-promoting volatile 2,3-butanediol and acetoin. Several other volatiles having biological functions in other organisms, as well as numerous volatile compounds with undefined biological roles, were detected. Together, these bacteria-derived volatiles can positively affect growth and metabolic parameters in green microalgae without physical attachment of the bacteria to the microalgae. This is a new paradigm on how PGPB promote growth of microalgae which may serve to improve performance of Chlorella spp. for biotechnological applications. PMID:28145473

  17. Loss of Cytochrome c Oxidase Activity and Acquisition of Resistance to Quinone Analogs in a Laccase-Positive Variant of Azospirillum lipoferum

    Science.gov (United States)

    Alexandre, Gladys; Bally, René; Taylor, Barry L.; Zhulin, Igor B.

    1999-01-01

    Laccase, a p-diphenol oxidase typical of plants and fungi, has been found recently in a proteobacterium, Azospirillum lipoferum. Laccase activity was detected in both a natural isolate and an in vitro-obtained phase variant that originated from the laccase-negative wild type. In this study, the electron transport systems of the laccase-positive variant and its parental laccase-negative forms were compared. During exponential (but not stationary) growth under fully aerobic (but not under microaerobic) conditions, the laccase-positive variant lost a respiratory branch that is terminated in a cytochrome c oxidase of the aa3 type; this was most likely due to a defect in the biosynthesis of a heme component essential for the oxidase. The laccase-positive variant was significantly less sensitive to the inhibitory action of quinone analogs and fully resistant to inhibitors of the bc1 complex, apparently due to the rearrangements of its respiratory system. We propose that the loss of the cytochrome c oxidase-containing branch in the variant is an adaptive strategy to the presence of intracellular oxidized quinones, the products of laccase activity. PMID:10542175

  18. In vitro PGPR properties and osmotic tolerance of different Azospirillum native strains and their effects on growth of maize under drought stress.

    Science.gov (United States)

    García, Julia E; Maroniche, Guillermo; Creus, Cecilia; Suárez-Rodríguez, Ramón; Ramirez-Trujillo, José Augusto; Groppa, María D

    2017-09-01

    Osmotic variations in the soil can affect bacterial growth diminishing the number of inoculated bacteria. In a scenario of water deficit having tolerant bacteria would be beneficial to achieve a better response of the plant to stress. Thus, selection of more resistant bacteria could be useful to design new inoculants to be used in arid zones. In this sense, a group of Azospirillum isolates deposited in INTA collection was characterized in order to select strains tolerant to osmotic stress. The results obtained demonstrated that Az19 strain has similar in vitro PGPR characteristics to Az39, the most used strain in Argentina for inoculants industries, with the advantage of a better tolerance to osmotic and salt stress. Inoculation of maize plants with this strain resulted in a better response against water deficit compared to Az39 strain, encouraging us to further study the behavior of this strain in greenhouse and field trials in view of developing new inoculants suitable for areas with water deficit. Copyright © 2017 Elsevier GmbH. All rights reserved.

  19. 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. Copyright © 2016 Elsevier GmbH. All rights reserved.

  20. 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. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  1. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Growth of Azospirillum irakense KBC1 on the Aryl β-Glucoside Salicin Requires either salA or salB

    Science.gov (United States)

    Faure, Denis; Desair, Jos; Keijers, Veerle; Bekri, My Ali; Proost, Paul; Henrissat, Bernard; Vanderleyden, Jos

    1999-01-01

    The rhizosphere nitrogen-fixing bacterium Azospirillum irakense KBC1 is able to grow on pectin and β-glucosides such as cellobiose, arbutin, and salicin. Two adjacent genes, salA and salB, conferring β-glucosidase activity to Escherichia coli, have been identified in a cosmid library of A. irakense DNA. The SalA and SalB enzymes preferentially hydrolyzed aryl β-glucosides. A Δ(salA-salB) A. irakense mutant was not able to grow on salicin but could still utilize arbutin, cellobiose, and glucose for growth. This mutant could be complemented by either salA or salB, suggesting functional redundancy of these genes in salicin utilization. In contrast to this functional homology, the SalA and SalB proteins, members of family 3 of the glycosyl hydrolases, show a low degree of amino acid similarity. Unlike SalA, the SalB protein exhibits an atypical truncated C-terminal region. We propose that SalA and SalB are representatives of the AB and AB′ subfamilies, respectively, in glycosyl hydrolase family 3. This is the first genetic implication of this β-glucosidase family in the utilization of β-glucosides for microbial growth. PMID:10321999

  3. 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.

  4. 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.

  5. 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. FEMS Microbiology Letters © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. No claim to original US government works.

  6. 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.

    2012-01-01

    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. PMID:22983183

  7. 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.

  8. 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......, andrastin A, pulvilloric acid, paxillin, paspaline and janthitrem, were commonly produced by these phylogenetically related species. The novel species had a high growth rate on agar media, but could be distinguished from each other by several macro- and microscopical characteristics....

  9. Uji Fitokimia, Kandungan Total Fenol dan Aktivitas Antioksidan Mikroalga Spirulina sp., Chlorella sp., dan Nannochloropsis sp.

    Directory of Open Access Journals (Sweden)

    Diini Fithriani

    2015-12-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui kandungan fitokimia, total fenol, dan aktivitas antioksidan dari mikroalga Spirulina sp., Nannochloropsis sp., dan Chlorella sp. Mikroalga diekstrak dengan ekstraksi tunggal menggunakan etanol. Skrining fitokimia dilakukan secara kualitatif. Analisis total fenol dilakukan secara spektrofotometri dengan metode Folin-Ciocalteu. Analisis antioksidan dilakukan dengan metode 2,2-diphenyl-1-picrylhydrazyl (DPPH dan Ferric Reducing Antioxidant Power (FRAP. Skrining fitokimia menunjukkan keberadaan tanin, flavonoid, steroid, glikosida, dan alkaloid pada ekstrak etanol ketiga jenis mikroalga, sedangkan saponin hanya terdeteksi pada ekstrak etanol Spirulina sp. dan Chlorella sp., adapun triterpenoid tidak terdeteksi pada ekstrak etanol ketiga jenis mikroalga. Hasil penelitian menunjukkan bahwa kandungan total fenol, aktivitas antioksidan (IC50, dan kapasitas antioksidan (FRAP tertinggi diperoleh pada ekstrak etanol Spirulina sp. dengan nilai berturut turut sebesar 0,32 ± 0,025 mg GAE g-1D.W., 518,94 ppm, dan  49,95 ± 2,02 (mmol Fe2+ eq.g-1D.W. Dalam penelitian ini diketahui bahwa kandungan fenol total memiliki korelasi  yang kuat  dengan kapasitas antioksidan metode FRAP (R2= 0,84, dan aktivitas antioksidan metode DPPH (R2= 0,79.

  10. Uji Fitokimia, Kandungan Total Fenol Dan Aktivitas Antioksidan Mikroalga Spirulina Sp., Chlorella Sp., dan Nannochloropsis Sp.

    Directory of Open Access Journals (Sweden)

    Diini Fithriani

    2015-12-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui kandungan fitokimia, total fenol, dan aktivitas antioksidan dari mikroalga Spirulina sp., Nannochloropsis sp., dan Chlorella sp. Mikroalga diekstrak dengan ekstraksi tunggal menggunakan etanol. Skrining fitokimia dilakukan secara kualitatif. Analisis total fenol dilakukan secara spektrofotometri dengan metode Folin-Ciocalteu. Analisis antioksidan dilakukan dengan metode 2,2-diphenyl-1-picrylhydrazyl (DPPH dan Ferric Reducing Antioxidant Power (FRAP. Skrining fitokimia menunjukkan keberadaan tanin, flavonoid, steroid, glikosida, dan alkaloid pada ekstrak etanol ketiga jenis mikroalga, sedangkan saponin hanya terdeteksi pada ekstrak etanol Spirulina sp. dan Chlorella sp., adapun triterpenoid tidak terdeteksi pada ekstrak etanol ketiga jenis mikroalga. Hasil penelitian menunjukkan bahwa kandungan total fenol, aktivitas antioksidan (IC50, dan kapasitas antioksidan (FRAP tertinggi diperoleh pada ekstrak etanol Spirulina sp. dengan nilai berturut turut sebesar 0,32 ± 0,025 mg GAE g-1D.W., 518,94 ppm, dan  49,95 ± 2,02 (mmol Fe2+ eq.g-1D.W. Dalam penelitian ini diketahui bahwa kandungan fenol total memiliki korelasi  yang kuat  dengan kapasitas antioksidan metode FRAP (R2= 0,84, dan aktivitas antioksidan metode DPPH (R2= 0,79.

  11. 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%). © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

  12. 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)

    Alsterfjord, Magnus; Nilson, Bo; Butler, Èile; Vásquez, Alejandra

    2014-01-01

    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 delbrueckiisubgroups 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 Fhon13NT ( = DSM 26257T = CCUG 63287T), Bin4NT ( = DSM 26254T = CCUG 63291T), Hon2NT ( = DSM 26255T = CCUG 63289T), Hma8NT ( = DSM 26256T = CCUG 63629T), Hma2NT ( = DSM 26263T = CCUG 63633T), Bma5NT ( = DSM 26265T = CCUG 63301T) and Biut2NT ( = DSM 26262T = CCUG 63631T). PMID:24944337

  13. Carbon and nitrogen limitation explain the contrasting responses of rhizospheric N-cycling microbial communities to maize inoculation by Azospirillum lipoferum CRT1

    Science.gov (United States)

    Florio, Alessandro; Pommier, Thomas; Gervaix, Jonathan; Bréfort, Caroline; Bérard, Annette; Le Roux, Xavier

    2017-04-01

    Introduction Maize inoculation with the plant-growth promoting rhizobacterium Azospirillum stimulates root growth and carbon, C, exudation, thereby enabling a better exploitation of soil and enhancing plant uptake of nitrogen, N. This can modulate the availability of N in the rhizosphere, by enhancing plant-microbe competition for N and modifying rhizosphere environmental variables important for N-cycling microbial communities, i.e. the amount of soil mineral N and oxygen availability. We tested the hypothesis that inoculation-induced stimulation of root N uptake and C exudation would enhance plant competition over microorganisms for N while increasing C availability for heterotrophs, thus leading to (i) a decrease of nitrifier abundance and activity, and (ii) a decrease or increase of denitrifier abundance and activity depending on the level of denitrifier limitation by N and C. Methods The extent of inoculation-induced changes in microbial activities (potential nitrification and denitrification), abundances and diversity of (de)nitrifiers as well as in root functional traits was assessed at 4 dates over two consecutive years in a multi-site field trial. Measurements were performed for the 6- and 12-leaves maize stages. In a second experiment, we artificially altered the level of denitrifier limitation by N and C in a greenhouse pot experiment by applying synthetic root exudates to inoculated and non-inoculated maize plants. Inoculation-induced response to nutrient limitation on microbial N-related activities and abundances was assessed for the 6-leaves stage maizeplants. Results Inoculation resulted in an idiosyncratic response of nitrification and nitrifier (AOA, AOB) abundance, which varied from one sampling date to another at a given site, and between sites and treatments at a given date. Modifications of water balance and soil moisture rather than increased plant-nitrifiers competition for soil NH4+ were the main drivers of nitrification. Conversely

  14. Ecdysteroids from a Zoanthus sp.

    Science.gov (United States)

    Suksamrarn, Apichart; Jankam, Aroon; Tarnchompoo, Bongkoch; Putchakarn, Sumaitt

    2002-08-01

    A new ecdysteroid, zoanthusterone, has been isolated from a marine zoanthid, Zoanthus sp. Ten known ecdysteroids, ponasterone A, 20-hydroxyecdysone 2-acetate, viticosterone E, integristerone A 25-acetate, 2-deoxy-20-hydroxyecdysone, ecdysone, ajugasterone C, dacryhainansterone, inokosterone, and 20-hydroxyecdysone, have also been isolated. This is the first report of ecdysteroids in a Zoanthus species.

  15. Sporulation of Cyclospora sp. oocysts.

    OpenAIRE

    Smith, H V; Paton, C A; Mitambo, M M; Girdwood, R W

    1997-01-01

    Cyclospora sp. oocysts sporulated maximally at 22 and 30 degrees C for 14 days retarded sporulation. Up to 12% of human- and baboon-derived oocysts previously stored at 4 degrees C for 1 to 2 months sporulated when stored for 6 to 7 days at 30 degrees C.

  16. 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.

  17. Dual RNA-seq transcriptional analysis of wheat roots colonized by Azospirillum brasilense reveals up-regulation of nutrient acquisition and cell cycle genes.

    Science.gov (United States)

    Camilios-Neto, Doumit; Bonato, Paloma; Wassem, Roseli; Tadra-Sfeir, Michelle Z; Brusamarello-Santos, Liziane C C; Valdameri, Glaucio; Donatti, Lucélia; Faoro, Helisson; Weiss, Vinicius A; Chubatsu, Leda S; Pedrosa, Fábio O; Souza, Emanuel M

    2014-05-16

    The rapid growth of the world's population demands an increase in food production that no longer can be reached by increasing amounts of nitrogenous fertilizers. Plant growth promoting bacteria (PGPB) might be an alternative to increase nitrogenous use efficiency (NUE) in important crops such wheat. Azospirillum brasilense is one of the most promising PGPB and wheat roots colonized by A. brasilense is a good model to investigate the molecular basis of plant-PGPB interaction including improvement in plant-NUE promoted by PGPB. We performed a dual RNA-Seq transcriptional profiling of wheat roots colonized by A. brasilense strain FP2. cDNA libraries from biological replicates of colonized and non-inoculated wheat roots were sequenced and mapped to wheat and A. brasilense reference sequences. The unmapped reads were assembled de novo. Overall, we identified 23,215 wheat expressed ESTs and 702 A. brasilense expressed transcripts. Bacterial colonization caused changes in the expression of 776 wheat ESTs belonging to various functional categories, ranging from transport activity to biological regulation as well as defense mechanism, production of phytohormones and phytochemicals. In addition, genes encoding proteins related to bacterial chemotaxi, biofilm formation and nitrogen fixation were highly expressed in the sub-set of A. brasilense expressed genes. PGPB colonization enhanced the expression of plant genes related to nutrient up-take, nitrogen assimilation, DNA replication and regulation of cell division, which is consistent with a higher proportion of colonized root cells in the S-phase. Our data support the use of PGPB as an alternative to improve nutrient acquisition in important crops such as wheat, enhancing plant productivity and sustainability.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. [The effect of combined and separate inoculation of alfalfa plants with Azospirillum lipoferum and Sinorhizobium meliloti on denitrification and nitrogen-fixing activities].

    Science.gov (United States)

    Furina, E K; Bonartseva, G A

    2007-01-01

    The effects of associative nitrogen fixer Azospirillum lipoferum strain 137 and root nodule bacteria Sinorhizobium meliloti after combined and separate inoculation of alfalfa seedlings on the background of mineral nitrogen applied at various times were studied. It was demonstrated that exudates of the alfalfa seedlings with the first pair of cotyledonary leaves already provide a high activity of these bacteria in the rhizosphere. To 74.6% of the introduced nitrate was transformed into N2O when the binary preparation of these bacteria was used. In an extended experiment (30 days), an active reduction of nitrates to N2O (11 micromol N2O/pot x 24 h) with inhibition of nitrogen fixation was observed in all of the experimental variants during the formation of legume-rhizobial and associative symbioses and simultaneous introduction of nitrates and bacteria. The most active enzyme fixation was observed in the case of a late (after 14 days) application of nitrates in the variants with both separate inoculations and inoculation with the binary preparation of A. lipoferum and S. meliloti. Separation in time of the application of bacterial preparations and mineral nitrogen assisted its preservation in all of the experimental variants. The variant of alfalfa inoculation with the binary preparation of A. lipoferum and S. meliloti and application of nitrates 2 weeks after inoculation was optimal for active nitrogen fixation (224.7 C2H4 nmol/flask x 24 h) and low denitrification activity (1.8 x micromol N2O/flask x 24 h). These results are useful in applied developments aimed at the use of bacterial and mineral fertilizers for leguminous plants.

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

    Directory of Open Access Journals (Sweden)

    Yanis A Boumber

    2008-08-01

    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.

  1. Antioxidant capacity, polyphenol content and iron bioavailability from algae (Ulva sp., Sargassum sp. and Porphyra sp.) in human subjects.

    Science.gov (United States)

    García-Casal, Maria N; Ramírez, José; Leets, Irene; Pereira, Ana C; Quiroga, Maria F

    2009-01-01

    Marine algae are easily produced and are good sources of Fe. If this Fe is bioavailable, algae consumption could help to combat Fe deficiency and anaemia worldwide. The objective of the present study was to evaluate Fe bioavailability, polyphenol content and antioxidant capacity from three species of marine algae distributed worldwide. A total of eighty-three subjects received maize- or wheat-based meals containing marine algae (Ulva sp., Sargassum sp. and Porphyra sp.) in different proportions (2.5, 5.0 and 7.5 g) added to the water to prepare the dough. All meals administered contained radioactive Fe. Absorption was evaluated calculating radioactive Fe incorporation in subjects' blood. The three species of marine algae were analysed for polyphenol content and reducing power. Algae significantly increased Fe absorption in maize- or wheat-based meals, especially Sargassum sp., due to its high Fe content. Increases in absorption were dose-dependent and higher in wheat- than in maize-based meals. Total polyphenol content was 10.84, 18.43 and 80.39 gallic acid equivalents/g for Ulva sp., Porphyra sp. and Sargassum sp., respectively. The antioxidant capacity was also significantly higher in Sargassum sp. compared with the other two species analysed. Ulva sp., Sargassum sp. and Porphyra sp. are good sources of bioavailable Fe. Sargassum sp. resulted in the highest Fe intake due to its high Fe content, and a bread containing 7.5 g Sargassum sp. covers daily Fe needs. The high polyphenol content found in Sargassum sp. could be partly responsible for the antioxidant power reported here, and apparently did not affect Fe absorption.

  2. Pantoea rodasii sp. nov., Pantoea rwandensis sp. nov. and Pantoea wallisii sp. nov., isolated from Eucalyptus.

    Science.gov (United States)

    Brady, Carrie L; Cleenwerck, Ilse; van der Westhuizen, Lorinda; Venter, Stephanus N; Coutinho, Teresa A; De Vos, Paul

    2012-07-01

    Several Gram-negative-staining, facultatively anaerobic bacterial isolates were obtained from Eucalyptus seedlings showing symptoms of bacterial blight and dieback in Colombia, Rwanda and South Africa. Partial 16S rRNA gene sequencing, together with partial gyrB sequencing, placed the isolates in the genus Pantoea and indicated that they constituted three novel species. Multilocus sequence analysis (MLSA) based on partial sequences of gyrB, rpoB, infB and atpD revealed Pantoea dispersa, Pantoea eucrina and Pantoea cypripedii as their closest phylogenetic relatives. DNA-DNA hybridization studies confirmed the classification of the new isolates as three novel species and phenotypic tests allowed them to be differentiated from their closest phylogenetic neighbours. The names Pantoea rodasii sp. nov. [type strain LMG 26273(T)=BD 943(T) (deposited with the Plant Pathogenic and Plant Protecting Bacteria Collection, South Africa)=BCC 581(T) (deposited with the Bacterial Culture Collection, Forestry and Agricultural Institute, South Africa)], Pantoea rwandensis sp. nov. (type strain LMG 26275(T)=BD 944(T)=BCC 571(T)) and Pantoea wallisii sp. nov. (type strain LMG 26277(T)=BD 946(T)=BCC 682(T)) are proposed.

  3. Optogenetic Manipulation of Cyclic Di-GMP (c-di-GMP) Levels Reveals the Role of c-di-GMP in Regulating Aerotaxis Receptor Activity in Azospirillum brasilense.

    Science.gov (United States)

    O'Neal, Lindsey; Ryu, Min-Hyung; Gomelsky, Mark; Alexandre, Gladys

    2017-09-15

    Bacterial chemotaxis receptors provide the sensory inputs that inform the direction of navigation in changing environments. Recently, we described the bacterial second messenger cyclic di-GMP (c-di-GMP) as a novel regulator of a subclass of chemotaxis receptors. In Azospirillum brasilense , c-di-GMP binds to a chemotaxis receptor, Tlp1, and modulates its signaling function during aerotaxis. Here, we further characterize the role of c-di-GMP in aerotaxis using a novel dichromatic optogenetic system engineered for manipulating intracellular c-di-GMP levels in real time. This system comprises a red/near-infrared-light-regulated diguanylate cyclase and a blue-light-regulated c-di-GMP phosphodiesterase. It allows the generation of transient changes in intracellular c-di-GMP concentrations within seconds of irradiation with appropriate light, which is compatible with the time scale of chemotaxis signaling. We provide experimental evidence that binding of c-di-GMP to the Tlp1 receptor activates its signaling function during aerotaxis, which supports the role of transient changes in c-di-GMP levels as a means of adjusting the response of A. brasilense to oxygen gradients. We also show that intracellular c-di-GMP levels in A. brasilense change with carbon metabolism. Our data support a model whereby c-di-GMP functions to imprint chemotaxis receptors with a record of recent metabolic experience, to adjust their contribution to the signaling output, thus allowing the cells to continually fine-tune chemotaxis sensory perception to their metabolic state. IMPORTANCE Motile bacteria use chemotaxis to change swimming direction in response to changes in environmental conditions. Chemotaxis receptors sense environmental signals and relay sensory information to the chemotaxis machinery, which ultimately controls the swimming pattern of cells. In bacteria studied to date, differential methylation has been known as a mechanism to control the activity of chemotaxis receptors and

  4. Protection of Tomato Seedlings against Infection by Pseudomonas syringae pv. Tomato by Using the Plant Growth-Promoting Bacterium Azospirillum brasilense†

    Science.gov (United States)

    Bashan, Yoav; de-Bashan, Luz E.

    2002-01-01

    Pseudomonas syringae pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium Azospirillum brasilense were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. The population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. When inoculated onto separate plants, the A. brasilense population in the rhizosphere of tomato plants was 2 orders of magnitude greater than the population of P. syringae pv. tomato (107 versus 105 CFU/g [dry weight] of root). Under mist chamber conditions, the leaf population of P. syringae pv. tomato was 1 order of magnitude greater than that of A. brasilense (107 versus 106 CFU/g [dry weight] of leaf). Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the A. brasilense population, the prevention of bacterial speck disease development, and improved plant growth. Inoculation of leaves with the mixed bacterial culture under mist conditions significantly reduced the P. syringae pv. tomato population and significantly decreased disease severity. Challenge with P. syringae pv. tomato after A. brasilense was established in the leaves further reduced both the population of P. syringae pv. tomato and disease severity and significantly enhanced plant development. Both bacteria maintained a large population in the rhizosphere for 45 days when each was inoculated separately onto tomato seeds (105 to 106 CFU/g [dry weight] of root). However, P. syringae pv. tomato did not survive in the rhizosphere in the presence of A. brasilense. Foliar inoculation of A. brasilense after P. syringae pv. tomato was established on the leaves did not alleviate bacterial speck disease, and A. brasilense did not survive well in the phyllosphere under these conditions, even in a mist chamber. Several applications

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

    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.

  6. Cross-talk between cognate and noncognate RpoE sigma factors and Zn(2+)-binding anti-sigma factors regulates photooxidative stress response in Azospirillum brasilense.

    Science.gov (United States)

    Gupta, Namrata; Gupta, Ankush; Kumar, Santosh; Mishra, Rajeev; Singh, Chhaya; Tripathi, Anil Kumar

    2014-01-01

    Azospirillum brasilense harbors two redox-sensitive Zinc-binding anti-sigma (ZAS) factors (ChrR1 and ChrR2), which negatively regulate the activity of their cognate extra-cytoplasmic function (ECF) σ factors (RpoE1 and RpoE2) by occluding their binding to the core enzyme. Both pairs of RpoE-ChrR control responses to photooxidative stress. The aim of this study was to investigate whether the two RpoE-ChrR pairs cross-talk while responding to the stress. In silico analysis showed a high sequence similarity between ChrR1 and ChrR2 proteins, but differences in redox sensitivity. Using in silico and in vitro methods of protein-protein interaction, we have shown that both ChrR1 and ChrR2 proteins physically bind to their noncognate RpoE proteins. Restoration of the phenotypes of chrR1::Tn5 and chrR2::Km mutants related to carotenoid biosynthesis and photooxidative stress tolerance by expressing chrR1 or chrR2 provided in vivo evidence for the cross-talk. In addition, up- or down-regulation of several identical proteins by expressing chrR1 or chrR2 in the chrR1::Tn5 mutant provided another in vivo evidence for the cross-talk. Although multiple redox-sensitive ZAS anti-σ factors occur in some Gram-positive bacteria, no cross-talk is reported among them. We report here, for the first time, that the two ZAS anti-σ factors of A. brasilense also interact with their noncognate σ factors and affect gene expression. The two redox-sensitive ZAS anti-σ factors in A. brasilense may interact with their cognate as well as noncognate ECF σ factors to play an important role in redox homeostasis by facilitating recovery from the oxidative stress.

  7. Role of ethylene and related gene expression in the interaction between strawberry plants and the plant growth-promoting bacterium Azospirillum brasilense.

    Science.gov (United States)

    Elías, J M; Guerrero-Molina, M F; Martínez-Zamora, M G; Díaz-Ricci, J C; Pedraza, R O

    2018-01-19

    Induced systemic resistance (ISR) is one of the indirect mechanisms of growth promotion exerted by plant growth-promoting bacteria, and can be mediated by ethylene (ET). We assessed ET production and the expression of related genes in the Azospirillum-strawberry plant interaction. Ethylene production was evaluated by gas chromatography in plants inoculated or not with A. brasilense REC3. Also, plants were treated with AgNO 3 , an inhibitor of ET biosynthesis; with 1-aminocyclopropane-1-carboxylic acid (ACC), a precursor of ET biosynthesis; and with indole acetic acid (IAA). Plant dry biomass and the growth index were determined to assess the growth-promoting effect of A. brasilense REC3 in strawberry plants. Quantitative real time PCR (qRT-PCR) was performed to analyse relative expression of the genes Faetr1, Faers1 and Faein4, which encode ET receptors; Factr1 and Faein2, involved in the ET signalling pathway; Faacs1 encoding ACC synthase; Faaco1 encoding ACC oxidase; and Faaux1 and Faami1 for IAA synthesis enzymes. Results showed that ET acts as a rapid and transient signal in the first 12 h post-treatment. A. brasilense REC3-inoculated plants had a significantly higher growth index compared to control plants. Modulation of the genes Faetr1, Faers1, Faein4, Factr1, Faein2 and Faaco1 indicated activation of ET synthesis and signalling pathways. The up-regulation of Faaux1 and Faami1 involved in IAA synthesis suggested that inoculation with A. brasilense REC3 induces production of this auxin, modulating ET signalling. Ethylene production and up-regulation of genes associated with ET signalling in strawberry plants inoculated with A. brasilense REC3 support the priming activation characteristic of ISR. This type of resistance and the activation of systemic acquired resistance previously observed in this interaction indicate that both are present in strawberry plants, could act synergistically and increase protection against pathogens. © 2018 German Society

  8. Efecto de la temperatura y el pH en la producción de biomasa de Azospirillum brasilense C16 aislada de pasto guinea

    Directory of Open Access Journals (Sweden)

    F Romero-Perdomo

    Full Text Available El objetivo del estudio fue evaluar el efecto de la temperatura y el pH en la viabilidad celular de la cepa Azospirillum brasilense C16. Se estudiaron cinco temperaturas (entre 28 y 36°C y cinco pH (de 4,5 a 8,5. El efecto de la temperatura se evaluó mediante la medición del crecimiento radial (mm de la cepa, sobre un papel de filtro en medio batata. En el caso del pH se utilizó un fermentador de tanque agitado -con una configuración tipo Rushton- para cuantificar la velocidad de crecimiento, la producción de biomasa y el tiempo de duplicación de la cepa; las condiciones de fermentación fueron: 400 rpm, 1 Lpm y 30°C, durante 24 horas. El pH y la temperatura influyeron significativamente (p < 0,05 en la producción de A. brasilense C16. La temperatura de 30°C fue la más favorable para que se multiplicara la cepa, con 23,21 mm de crecimiento radial; mientras que la mayor o igual a 34°C inhibió su crecimiento. Los mejores resultados se obtuvieron con un pH de 6,8, con diferencias significativas (p < 0,05 respecto al resto. Con esta condición se obtuvieron los valores más altos de velocidad de crecimiento (1,79 h-1 y producción de biomasa (8,65 log10 UFC mL-1, y el valor más bajo del tiempo de duplicación (1,09 h-1. Estos resultados poseen aplicabilidad biotecnológica, y son de gran importancia en el momento de definir y controlar las condiciones de producción masiva de biomasa de A. brasilense C16 para futuras formulaciones como biofertilizante en diversos cultivos de interés en Colombia.

  9. Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense.

    Science.gov (United States)

    Brusamarello-Santos, Liziane Cristina; Gilard, Françoise; Brulé, Lenaïg; Quilleré, Isabelle; Gourion, Benjamin; Ratet, Pascal; Maltempi de Souza, Emanuel; Lea, Peter J; Hirel, Bertrand

    2017-01-01

    Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number

  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. 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

  12. Co-inoculation effects of Bradyrhizobium japonicum and ...

    African Journals Online (AJOL)

    Co-inoculation effects of Bradyrhizobium japonicum and Azospirillum sp. on competitive nodulation and rhizosphere eubacterial community structures of soybean under rhizobia-established soil conditions.

  13. Especificidad del hongo micorrizico (Rhizoctonia sp.) en Phalaenopsis sp., Cymbidium sp., Trichoceros antenifer, Oncidium excavatum, y Cyrtochilum sp.

    OpenAIRE

    Ordoñez, Silvia L.; Pillacela Zhunio, Dora Priscila; Salazar, Jazmín M.; Peña Tapia, Denisse Fabiola

    2016-01-01

    Las orquídeas producen abundantes semillas pequeñas, careciendo de endospermo, cotiledones y sustancias de reserva para llevar a cabo su germinación. Es por esto que estratégicamente las semillas establecen una relación simbiótica con un hongo micorrízico que favorece a su germinación y desarrollo. El objetivo de este estudio fue determinar la especificidad del hongo micorrízico (Rhizoctonia sp.) en la germinación de cinco géneros de orquídeas. Se usaron dos medios de cultivo: 1) PhytamaxTM y...

  14. Rodentibacter gen. nov including Rodentibacter pneumotropicus comb. nov., Rodentibacter heylii sp nov., Rodentibacter myodis sp nov., Rodentibacter ratti sp nov., Rodentibacter heidelbergensis sp nov., Rodentibacter trehalosifermentans sp nov., Rodentibacter rarus sp nov., Rodentibacter mrazii

    DEFF Research Database (Denmark)

    Adhikary, Sadhana; Nicklas, Werner; Bisgaard, Magne

    2017-01-01

    genomic comparison allowed the estimation of DNA–DNA renaturation. Rodentibacter heylii sp. nov. was proposed for a group that included the biovar Heyl of [ Pasteurella ] pneumotropica with the type strain ATCC 12555T (=CCUG 998T). A group was proposed as Rodentibacter ratti sp. nov., which included...

  15. Xylanolytic enzyme systems in Arthrobacter sp MTCC 5214 and Lactobacillus sp.

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, R.; Jalal, T.

    The production of extracellular xylanolytic enzymes such as xylanase, alfa-L-arabinofuranosidase (alfa-l-AFase), and acetyl xylan esterase (Axe) by marine Arthrobacter sp and Lactobacillus sp was investigated using different carbon sources Induction...

  16. Evaluation of antioxidant and cytotoxic properties of Cynobacteria, Limnothrix sp. and Leptolyngbya sp. from Arabian sea

    Digital Repository Service at National Institute of Oceanography (India)

    Anas, A.; Vinothkumar, S.; Gupta, S.; Jasmin, C.; Joseph, V.; Parameswaran, P.S.; Nair, S.

    The hexane fractions of the marine cyanobacteria: Leptolyngbya sp. and Limnothrix sp., collected from Arabian Sea were found to display promising antioxidant properties than their ethyl acetate fraction during radical scavenging ABTS/DPPH assays (IC...

  17. 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

  18. 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

  19. First report of Anisakis sp. in Epinephelus sp. in East Indonesia

    OpenAIRE

    Annytha Ina Rohi Detha; Diana Agustiani Wuri; Julianty Almet; Yuni Riwu; Christin Melky

    2018-01-01

    Objective: The present research was conducted to identify the prevalence of Anisakis sp. as fish-borne zoonoses in Epinephelus sp. in territorial waters of East Nusa Tenggara, Indonesia. Materials and methods: A total of 50 fish (Epinephelus sp.) were collected from Kupang Fish Market in East Nusa Tenggara. Identification of Anisakis sp. was performed based on morphological observations considering shape of ventriculus, boring tooth, and mucron using binocular microscope. Results: Prev...

  20. Specialised predation by Palpimanus sp. (Araneae: Palpimanidae ...

    African Journals Online (AJOL)

    This is the first detailed report on the natural prey and the prey-capture tactics of a Palpimanus sp. from Entebbe (Uganda). Although this species fed occasionally on insects, its dominant prey in the field was other spiders, especially jumping spiders (Salticidae) and their eggs. Encounters between Palpimanus sp. and ...

  1. Guide til gode spørgeskemaer

    DEFF Research Database (Denmark)

    Olsen, Henning

    Spørgeskemaundersøgelser bliver ofte brugt til at dokumentere forskellige forhold og begrunde politiske beslutninger. Men resultaterne kan være forbundet med stor usikkerhed. Det kræver omhu og stor sproglig formåen at udarbejde spørgeskemaer. Seniorforsker Henning Olsen har i flere år arbejdet med...... viden om, hvordan folk forstår sproglige meddelelser og genkalder sig informationer. I guiden behandles emner som fx styrende problemstillinger og spørgsmåls fokus og neutralitet, formulering af åbne eller lukkede spørgsmål og svarkategorier, tematiske spørgeforløb, aflastning af svarpersoners...

  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. © 2014 IUMS.

  3. EFECTO DE LA INOCULACIÓN DE Azospirillum halopraeferens Y Bacillus amyloliquefaciens EN LA GERMINACIÓN DE Prosopis chilensis

    Directory of Open Access Journals (Sweden)

    J.A. Villegas-Espinoza

    2009-07-01

    Full Text Available Las Bacterias Promotoras de Crecimiento de Plantas (BPCP, son microorganismos fijadores de nitrógeno atmosférico y a su vez producen hormonas que aprovechan las plantas para llevar a cabo su desarrollo. Es importante la utilización de microorganismos benéficos para reducir la fertilización química. La investigación científica ha incrementado la busqueda y aislamiento de BPCP de regiones especificas como son las zonas áridas, ya que estos microorganismos estan adaptados a ambientes extremos. La especie Prosopis chilensis esta siendo utilizada para reforestación de escuelas, parques y también como ornato; para reproducir esta planta se esta utilizando fertilizantes químicos que son dañinos al medio ambiente. El objetivo de la presente investigación, consistió en analizar el efecto promotor de las bacterias promotoras del crecimiento vegetal Bacillus amyloliquefaciens y Azospirillum halopraeferens en la germinación y emergencia del mezquite chileno (P. chilensis bajo cuatro concentraciones salinas (0, 0.25, 0.5 y 0.75 M de NaCl. Se obtuvieron semillas de mezquite chileno de la región de Santa Ana, Sonora, México. Bajo condiciones de laboratorio se evaluó el porcentaje de germinación, tasa de germinación, altura, longitud radicular de plántula, peso fresco de plántula número de células bacterianas adheridas al sistema radicular. Bajo condiciones de invernadero, las variables evaluadas fueron porcentaje de emergencia, tasa de emergencia, altura y longitud radicular, peso fresco y seco de planta, peso fresco y seco de raíz, número de células bacterianas adheridas al sistema radicular. Los resultados indican que, bajo condiciones in vitro, el porcentaje y tasa de germinación disminuyó conforme la salinidad se incrementa. Sin embargo, estas variables fueron afectadas positivamente por A. halopraeferens y B. amyloliquefaciens en comparación del tratamiento

  4. 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.

  5. Antibacterial Actions and Potential Phototoxic Effects of Volatile oils of Foeniculum sp. (fennel, Salvia sp. (sage, Vitis sp. (grape, Lavandula sp. (lavender

    Directory of Open Access Journals (Sweden)

    Elif Ayse Erdogan Eliuz

    2016-09-01

    Full Text Available In the present study, the volatile compounds of essential oil of Foeniculum vulgare (fennel, Salvia officinalis (sage, Vitis vinifera (grape, Lavandula angustifolia (lavender were analysed by gas chromatography-mass spectrometry (GC-MS using the Nist and Willey libraries. It was determined that the main components of Foeniculum sp. were anethole (41.11%, carvacrol (9.18%. whereas main components of Salvia sp were 1.8 cineole (34.09%, caryophyllene (10.95%, camphor (9.44%, α-pinene (8.42%. Vitis sp. contained linoleic acid (36.98%, 2,4-decadienal (30.79%. Finally, volatile component of Lavandula sp. was linalool (33.57%, linalyl acetate (30.74%. Photoxic antibacterial activity of volatile oil of those plants against Escherichia coli (ATCC 25293, Klebsiella pneumoniae (10031, Salmonella thyphimurium, Bacillus subtilis (ATCC 6633, Staphylococcus aureus (ATCC 25925, Enterococcus feacalis (ATCC 29212 were examined by using disc diffusion method. We demonstrated that volatile oil effectively can be activated by a standard LED light. In vitro, significant phototoxicity was demonstrated by volatile oil of Foeniculum sp. and Vitis sp. (P < 0.05, while minor phototoxicity was induced by Lavandula sp. Therefore, volatile oil of plant can be considered as a potential photosensitizer in the photochemical therapy.

  6. TurboSP and the Topological Trigger

    CERN Document Server

    Belavin, Vladislav

    2016-01-01

    TurboSP was originally proposed as an alternative to Full stream in LHCb data flow. TurboSP is a data flow strategy which not only selects events that should be preserved, like in Full stream, but also provides selective persistence. This is achieved by saving candidates and subset of the reconstruction. During this summer project we investigated the physics viability of using TurboSP with the topological lines and found out a possibility to reduce the number of kept tracks per event by two times while keeping a ratio of fully picked up interesting decay modes on $\\sim 97 \\%$ level.

  7. Amphibian (Xenopus sp.) iodothyronine deiodinase ...

    Science.gov (United States)

    The U.S. EPA-MED amphibian thyroid group is currently screening chemicals for inhibition of human iodothyronine deiodinase activity as components of the thyroid system important in human development. Amphibians are a bellwether taxonomic group to gauge toxicity of chemicals in the environment. Amphibian thyroid function is not only important in development but also metamorphosis. Xenopus sp. have been used extensively as model organisms and are well characterized genetically. We propose to screen a list of chemicals (selected from the human DIO screening results) to test for inhibition of Xenopus deiodinases. Large quantities of the enzymes will be produced using an adenovirus system. Our preliminary results show that there may be catalytic differences between human and Xenopus deiodinases. The Twin Ports Early Career Scientists is a new group formed within the Duluth-Superior scientific community. This presentation will provide a basic introduction to my research and our mission at EPA, and help to establish networking and collaboration relationships across disciplines and institutions.

  8. Detection of Salmonella sp., Vibrio sp. and total plate count bacteria on blood cockle (Anadara granosa)

    Science.gov (United States)

    Ekawati, ER; Yusmiati, S. N. H.

    2018-01-01

    Blood cockle (Anadara granosa) has high level of zinc and protein, which is beneficial for therapeutic function for malnourished particularly stunting case in children. Zinc in animal foods is more absorbable than that from vegetable food. Blood cockle (Anadara granosa) is rich in nutrient and an excellent environment for the growth of microorganisms. This research aimed to identify the contamination of Salmonella sp., Vibrio sp. and total plate count bacteria on blood cockle (Anadara granosa). This was observation research with laboratory analysis. Salmonella sp. and Vibrio sp. were detected from blood cockle. Total plate count was determine of the total amount of the bacteria. Results detected from 20 samples of blood cockle showed that all samples were negative of Salmonella sp. and 1 sample positive Vibrio sp. The result of total plate count bacteria was sample.

  9. Helicotylenchus stylocercus n. sp. and Rotylenchus phaliurus n. sp. (Nematoda: Hoplolaimidae) from Costa Rica.

    Science.gov (United States)

    Siddiqi, M R; Pinochet, J

    1979-10-01

    Two new species of plant-parasitic nematodes from Costa Rica are described. Helicotygenchus styloeercus n. sp., from soil around roots of banana at Coto, is distinguished hy the female tail, which bears a large pillarlike ventral projection. Rotylenchus phaliurus n. sp., from soil artmnd roots of Dioscoroea sp. at Sixaola, differs from R. caudaphasmidius in having the conus equal to or more than half the spear length, and large terminal annules on the female tail.

  10. SP (4,R) symmetry in light nuclei

    International Nuclear Information System (INIS)

    Peterson, D.R.

    1979-01-01

    A classification of nuclear states according to the noncompact sympletic Lie algebras sp(2n,R), n = 1, 2, 3, is investigated. Such a classification has recently been shown to be physically meaningful. This classification scheme is the appropriate generalization fo Elliott's SU 3 model of rotational states in deformed light nuclei to include core excitations. A restricted classification according to the Lie algebra, sp(4,R), is motivated. Truncation of the model space to a single sp(4,R) irreducible representation allows the inclusion of states possessing very high excitation energy. An sp(4,R) model study is performed on S = T = 0 positive-parity rotational bands in the deformed light nuclei 16 O and 24 Mg. States are included in the model space that possess up to 10h ω in excitation energy. Results for the B(E2) transition rates compare favorable with experiment, without resort to effective charges

  11. 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...

  12. 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.

  13. Penggunaan Jamur Antagonis Trichoderma SP. Dan Gliocladium SP. Untuk Mengendalikan Penyakit Layu Fusarium Pada Tanaman Bawang Merah (Allium Ascalonicum L.)

    OpenAIRE

    Arie Ramadhina, Arie Ramadhina; Lisnawita, Lisnawita; Lubis, Lahmuddin

    2013-01-01

    The use of antagonism fungus of Trichoderma sp. and Gliocladium sp. for controlling wilt(Fusarium oxysporum) in red onion plants. The aim of the research was to know the effectiviness ofantagonism fungus of Trichoderma sp. and Gliocladium sp. in controlling wilt in red onion plants.The research used non-factorial RAK (random group design) with eight treatments: control, 10grams of F. oxysporum, 12 grams of Trichoderma sp., 18 grams of Trichoderma sp., 24 grams ofTrichoderma sp., and 12 grams ...

  14. 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...

  15. 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

  16. Effect of Azospirillum brasilense on the harvest and radical development of sugar cane plants, variety C86 - 456, obtained by in vitro culture in normal conditions and under overhumidity of soil

    Directory of Open Access Journals (Sweden)

    Sergio Rodríguez Rodríguez

    2005-01-01

    Full Text Available In order to know the influence of the bacteria Azospirillum brasilense on plants of sugar cane, cultivar C86-456, from tissue culture under normal conditions and flooded soil in a Vertisol from El Valle del Cauto, an experiment was carried out using an at random blocks design. The main crop variables (pol in cane, t. caña.ha-1 and t. pol.ha-1 at the twelve months of age were taken, as stump of spring of the year and the development reached by the radical system in its more active area to achieve this experiment. The best results in the crop variables and development of the radical system were obtained it the treatments where the bacteria was present, although non significant under both conditions, evidencing that the stress due to excess of water in the soil affects the normal development of the sugar cane in general by modifying the kindness that the rhizospheric microorganism provides. Key words: biofertilizer, radical system, Saccharum, yield

  17. 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

    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

  18. SP-100/Brayton power system concepts

    International Nuclear Information System (INIS)

    Owen, D.F.

    1989-01-01

    Use of closed Brayton cycle (CBC) power conversion technology has been investigated for use with SP-100 reactors for space power systems. The CBC power conversion technology is being developed by Rockwell International under the Dynamic Isotype Power System (DIPS) and Space Station Freedom solar dynamic power system programs to provide highly efficient power conversion with radioisotype and solar collector heat sources. Characteristics including mass, radiator area, thermal power, and operating temperatures for systems utilizing SP-100 reactor and CBC power conversion technology were determined for systems in the 10-to 100-kWe power range. Possible SP-100 reactor/CBC power system configurations are presented. Advantages of CBC power conversion technology with regard to reactor thermal power, operating temperature, and development status are discussed

  19. 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

  20. Nitrogen fixation in Asaia sp. (family Acetobacteraceae).

    Science.gov (United States)

    Samaddar, Neeloy; Paul, Arundhati; Chakravorty, Somnath; Chakraborty, Writachit; Mukherjee, Joydeep; Chowdhuri, Debarati; Gachhui, Ratan

    2011-08-01

    The genus Asaia (family Acetobacteraceae) was first introduced with a single species-Asaia bogorensis and later six more species were described namely A. siamensis, A. krungthepensis, A. lannaensis, A. platycodi, A. prunellae, and A. astilbes. Acetobacteraceae family has been divided into ten genera but, only three of them include nitrogen fixing species: Gluconacetobacter, Acetobacter, and Swaminathania. This article originated from our study primarily aimed to isolate new endosymbiotic nitrogen fixer among Acetobacteraceae during which we have isolated, for the first time in India, four different strains of Asaia sp. from three different sources: Michalia champaca flower, Anopheles mosquito, and ant Tetraponera rufonigra. All the endosymbiotic strains isolated possess the ability to fix nitrogen. Evidence for both nitrogenase activity and the presence of nifH gene in isolated Asaia sp. is presented. Asaia bogorensis (MTCC 4041(T)) and A. siamensis (MTCC 4042(T)), two of the validated type strains available from the repository, were tested positive for the presence of functional nitrogenase. The nifH gene sequences from these type strains were also confirmed and compared with other nitrogen fixing members of the family Acetobacteraceae. Our result corroborate with the previous reports that Asaia sp. are indeed widely distributed in nature but this is the first time demonstration of their functional nitrogenase activity. This study shows Asaia sp. as fourth genera of nitrogen fixing bacteria in the family Acetobacteraceae.

  1. Molecular characterization of Trichoderma sp. isolated from ...

    African Journals Online (AJOL)

    The genetic relatedness among 15 isolates of Trichoderma sp. was analyzed with six micro-satellite primers. ISSR profiles showed 83.7% genetic diversity among the isolates with the formation of four clusters. Analysis of dendrogram revealed that similarity coefficient ranged from 0.27 to 0.95. ITS-PCR of rDNA region with ...

  2. Som man spørger

    DEFF Research Database (Denmark)

    Bjerg, Lars

    Indhold: Input og outputinterview ; Tre interviewtyper ; Tre grundprincipper ; De syv dødssynder ; Åbne, simple og neutrale spørgsmål ; Skuffespørgsmål ; Fokus ; Aktiv lytning ; Mål ; Strategi ; Abstrakt og konkret ; Det kritiske interview ; Kilder med et budskab ; Oldfruens fif ; Resumé i punktform...

  3. POTENSI MELANOTUS SP. DALAM MENDEGRADASI LIGNIN

    Directory of Open Access Journals (Sweden)

    NUNIK SULISTINAH

    2008-06-01

    Full Text Available Ten isolates of fungus were isolated from oil palm stem at oil palm plantation in Medan All of them were tested its abilities to degrade lignin. The results showed that one of them was able to grow on ligninase media and the fungi has the ability to degrade ligin. The fungi is identified as Melanotus sp.

  4. 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)

  5. Biosorption of uranium by Azolla, SP, Brazil

    International Nuclear Information System (INIS)

    Vieira, Ludmila C.; Alves, Eliakim G.; Marumo, Julio T.; Ferreira, Rafael V. de P.; Canevesi, Rafael L.S.; Silva, Edson A.

    2015-01-01

    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)

  6. 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...

  7. Lipid contents of the sponge Haliclona sp.

    Digital Repository Service at National Institute of Oceanography (India)

    Parameswaran, P.S.; Das, B.; Kamat, S.Y.

    Several fatty acids, sterols, batyl alcohol and its analogs and an N-acylated sphingosine (ceramide) have been isolated from the lipid fraction of the extract of the sponge Haliclona sp. The major sterol is found to be cholesterol (54%), followed...

  8. Test af spørgeskema

    DEFF Research Database (Denmark)

    Hermansen, Jonathan

    2017-01-01

    Denne bog gennemgår alle surveyarbejdets faser og giver en praktisk indføring i •design af undersøgelsen og udvælgelse af stikprøver, •formulering af spørgeskemaer samt indsamling og kodning af data, •metoder til at analysere resultaterne....

  9. Botrallin from the endophytic fungus Hyalodendriella sp ...

    African Journals Online (AJOL)

    use

    2011-12-12

    Dec 12, 2011 ... Bioassay-guided fractionation of the crude methanol extract of the mycelia from the endophytic fungus. Hyalodendriella sp. Ponipodef12, associated with the hybrid 'Neva' of Populus deltoides Marsh × P. nigra L., led to the isolation of one compound coded as P12-1 which was identified as botrallin (1,7-.

  10. C (sp2)–C (sp2) cross coupling reaction catalyzed by a palladacycle ...

    Indian Academy of Sciences (India)

    (sp2) cross coupling reaction catalyzed by a palladacycle phosphine complex: A simple and sustainable protocol in aqueous media. Seyyed Javad Sabounchei Marjan Hosseinzadeh. Articles Volume 127 Issue 11 November 2015 pp 1919- ...

  11. Nanocrystalline sp{sup 2} and sp{sup 3} carbons: CVD synthesis and applications

    Energy Technology Data Exchange (ETDEWEB)

    Terranova, M. L. [Università degli Studi di Roma “Tor Vergata,” via Della Ricerca Scientifica, Dipartimento di Scienze e Tecnologie Chimiche—MinimaLab (Italy); Rossi, M. [Università degli Studi di Roma “Sapienza,” via A. Scarpa, Dipartimento di Scienze di Base e Applicate per l’Ingegneria and Centro di Ricerca per le Nanotecnologie Applicate all’Ingegneria (CNIS) (Italy); Tamburri, E., E-mail: emanuela.tamburri@uniroma2.it [Università degli Studi di Roma “Tor Vergata,” via Della Ricerca Scientifica, Dipartimento di Scienze e Tecnologie Chimiche—MinimaLab (Italy)

    2016-11-15

    The design and production of innovative materials based on nanocrystalline sp{sup 2}- and sp{sup 3}-coordinated carbons is presently a focus of the scientific community. We present a review of the nanostructures obtained in our labs using a series of synthetic routes, which make use of chemical vapor deposition (CVD) techniques for the selective production of non-planar graphitic nanostructures, nanocrystalline diamonds, and hybrid two-phase nanostructures.

  12. Analisis Fosfor pada Cacing Tanah (Megascolex sp. dan Fridericia sp.) Secara Spektrofotometri Sinar Tampak

    OpenAIRE

    Safira, Cut Shafa

    2015-01-01

    Earthworm is natural resource which can be used for medication due to its highly amount of minerals. One of these minerals is phosphorus. The aim of this research are to identify, determine and know the difference content of phosphorus in Megascolex sp. and Fridericia sp. Qualitative analysis shows positive results with addition of ammonium molybdate 4% and BaCl2 5%. Quantitative analysis was done using visible spectrophotometer with ascorbic acid method, measuring blu-colored molybdenum ...

  13. Differences in nutrient uptake capacity of the benthic filamentous algae Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. under varying N/P conditions.

    Science.gov (United States)

    Liu, Junzhuo; Vyverman, Wim

    2015-03-01

    The N/P ratio of wastewater can vary greatly and directly affect algal growth and nutrient removal process. Three benthic filamentous algae species Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. were isolated from a periphyton bioreactor and cultured under laboratory conditions on varying N/P ratios to determine their ability to remove nitrate and phosphorus. The N/P ratio significantly influenced the algal growth and phosphorus uptake process. Appropriate N/P ratios for nitrogen and phosphorus removal were 5-15, 7-10 and 7-20 for Cladophora sp., Klebsormidium sp. and Pseudanabaena sp., respectively. Within these respective ranges, Cladophora sp. had the highest biomass production, while Pseudanabaena sp. had the highest nitrogen and phosphorus contents. This study indicated that Cladophora sp. had a high capacity of removing phosphorus from wastewaters of low N/P ratio, and Pseudanabaena sp. was highly suitable for removing nitrogen from wastewaters with high N/P ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Anomalous self potential (sp) log signatures observed in a water ...

    African Journals Online (AJOL)

    Geophysical logging was done after drilling had been completed in a water well at Okwudor, South Eastern Nigeria. Three electric logs were run viz: Self Potential (SP), Resistivity N16″ and N64″ logs. An anomaly was observed in the SP log. The SP results from this well show some deviation from the standard norm.

  15. Biosorption of chromium by mangrove-derived Aplanochytrium sp ...

    African Journals Online (AJOL)

    The microbial dried biomass of Thraustochytrids is used as bioadsorbent for the removal of the chromium in aqueous solution. In this investigation, three species of Thraustochydrids namely Aplanochytrium sp., Thraustochytrium sp. and Schizochytrium sp. were tested for the efficiency of chromium accumulation by culturing ...

  16. Babesia peircei sp. nov. from the jackass penguin

    African Journals Online (AJOL)

    1992-01-09

    Jan 9, 1992 ... An avian piroplasm, Babesia peircei sp. nov. is described from the jackass penguin Spheniscus demersus. Morphological differences between Babesia peircei sp. nov. and the other valid Babesia spp. are discussed together with the possible vectors. 'n Voal-piroplasma, Babesia peircei sp. nov. afkomstig ...

  17. Occurrence of Aspergillus sp., Fusarium sp., and aflatoxins in corn hybrids with different systems of storage

    Directory of Open Access Journals (Sweden)

    Adriana Sbardelotto Di Domenico

    2016-01-01

    Full Text Available The aim of this study was to assess alternatives for viable corn storage for small rural properties in two annual storage experiments. A 4×5 factorial design was used with four types of storage (conventional bags, hermetic bags, metal silos and corncobs and five periods of storage (0, 3, 6, 9 and 12 months. We used corn hybrids 2B688RR and 30K73Hx cultivated in winter 2012 and summer 2012/2013 in the city of Dois Vizinhos, Paraná, Brazil. The moisture contents, counts of Aspergillus sp. and Fusarium sp., and the occurrence of aflatoxins (B1, B2, G1 and G2 were assessed. The kernels stored in hermetic bags had lower moisture contents. Aspergillus sp. and Fusarium sp. were observed in 20.37 and 86.11% of winter storage samples, respectively, and in 83.3 and 91.6% of summer storage samples, respectively. The storage system and time of storage had no influence on the occurrence of Aspergillus sp. and aflatoxins in the winter crop samples. The corncobs from the summer crop samples had the lowest counts of Aspergillus sp. and did not have aflatoxins. We detected aflatoxins at concentrations of 2.8-14.5 and 3-197.5 µg kg-1 in the winter and summer crop samples, respectively.

  18. Two new species of suctorians, Acineta satyanandani sp. nov. and Paracineta karunakarani sp. nov. epizoic on ostracods

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.

    Two, species of protozoic suctorians, Acineta satyanandani sp. nov. and Paracineta karunakarani sp. nov., are described. These were found attached on the body of the marine ostracod, Cypridina dentata (Muller), collected from the shelf and slope...

  19. The family Carabodidae (Acari, Oribatida) VIII. The genus Machadocepheus (first part) Machadocepheusleoneae sp. n. and Machadocepheusrachii sp. n. from Gabon.

    Science.gov (United States)

    Fernandez, Nestor; Theron, Pieter; Rollard, Christine; Leiva, Sergio

    2014-01-01

    The genus Machadocepheus, being one of the more complex genera of the Carabodidae family, is briefly outlined to demonstrate this complexity. Descriptions of two new species from Gabon, Machadocepheusleoneae sp. n. and Machadocepheusrachii sp. n. are given.

  20. First report of Giardia sp. and Cryptosporidium sp. in fecal samples in blue macaw (Anodorhynchus hyacinthinus) in southern Brazil

    OpenAIRE

    Matheus Hillard Farret; Vinicius da Rosa Fanfa; Luisa Ragagnin; Aleksandro Schafer da Silva; Silvia Gonzalez Monteiro

    2010-01-01

    This study reports the gastrointestinal parasitism by Giardia sp. and Cryptosporidium sp. in blue macaw (Anodorhynchus hyacinthinus) in the southern region of Brazil. Fecal samples of two species kept in captivity in the state of Rio Grande do Sul were analyzed by the direct smear method, centrifugal flotation technique with zinc sulfate and Kinyoun staining technique for research of parasites. Mixed infection by eggs of Capillaria, cysts of Giardia sp. and oocysts of Cryptosporidium sp. was ...

  1. 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.

  2. Agromyces italicus sp. nov., Agromyces humatus sp. nov. and Agromyces lapidis sp. nov., isolated from Roman catacombs.

    Science.gov (United States)

    Jurado, Valme; Groth, Ingrid; Gonzalez, Juan M; Laiz, Leonila; Schuetze, Barbara; Saiz-Jimenez, Cesareo

    2005-03-01

    A polyphasic study was carried out to clarify the taxonomic positions of three Gram-positive isolates from the Catacombs of Domitilla, Rome (Italy). 16S rRNA gene sequence comparisons placed these strains within the genus Agromyces. The morphological and chemotaxonomic characteristics of these isolates were consistent with the description of the genus Agromyces. The three isolates could be readily distinguished from one another and from representatives of all Agromyces species with validly published names by a broad range of phenotypic characteristics and DNA-DNA relatedness studies. Therefore, these isolates are proposed to represent three novel species of the genus Agromyces, Agromyces italicus sp. nov. (type strain CD1(T)=HKI 0325(T)=DSM 16388(T)=NCIMB 14011(T)), Agromyces humatus sp. nov. (type strain CD5(T)=HKI 0327(T)=DSM 16389(T)=NCIMB 14012(T)) and Agromyces lapidis sp. nov. (type strain CD55(T)=HKI 0324(T)=DSM 16390(T)=NCIMB 14013(T)).

  3. Cryptotrichosporon argae sp. nov., Cryptotrichosporon brontae sp. nov. and Cryptotrichosporon steropae sp. nov., isolated from forest soils.

    Science.gov (United States)

    Pontes, Ana; Röhl, Oliver; Maldonado, Cristina; Yurkov, Andrey M; Sampaio, José Paulo

    2017-09-01

    Yeast strains belonging to the basidiomycetous genus Cryptotrichosporon were isolated from forest soils in Serra da Arrábida Natural Park in Portugal. Similar to the already-known representatives of this genus, the new isolates formed pigmented colonies of a distinctive pale orange colour. Phylogenetic analyses employing concatenated sequences of the D1/D2 domains of the 26S (large subunit) rRNA gene and the internal transcribed spacer (ITS) region supported the recognition of three novel species: Cryptotrichosporon argae sp. nov. (type strain CM 19T=CBS 14376T=PYCC 7010T=DSM 104550T; MycoBank accession number MB 817168), Cryptotrichosporon brontae sp. nov. (type strain CM 1562T=CBS 14303T=PYCC 7011T=DSM 104551T; MycoBank accession number MB 817077) and Cryptotrichosporon steropae sp. nov. (type strain OR 395T=CBS 14302T=PYCC 7012T=DSM 104552T; MycoBank accession number MB 817078).

  4. 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.

  5. A superhard sp3 microporous carbon with direct bandgap

    Science.gov (United States)

    Pan, Yilong; Xie, Chenlong; Xiong, Mei; Ma, Mengdong; Liu, Lingyu; Li, Zihe; Zhang, Shuangshuang; Gao, Guoying; Zhao, Zhisheng; Tian, Yongjun; Xu, Bo; He, Julong

    2017-12-01

    Carbon allotropes with distinct sp, sp2, and sp3 hybridization possess various different properties. Here, a novel all-sp3 hybridized tetragonal carbon, namely the P carbon, was predicted by the evolutionary particle swarm structural search. It demonstrated a low density among all-sp3 carbons, due to the corresponding distinctive microporous structure. P carbon is thermodynamically stable than the known C60 and could be formed through the single-walled carbon nanotubes (SWCNTs) compression. P carbon is a direct bandgap semiconductor displaying a strong and superhard nature. The unique combination of electrical and mechanical properties constitutes P carbon a potential superhard material for semiconductor industrial fields.

  6. Sp6 and Sp8 Transcription Factors Control AER Formation and Dorsal-Ventral Patterning in Limb Development

    Science.gov (United States)

    Haro, Endika; Delgado, Irene; Junco, Marisa; Yamada, Yoshihiko; Mansouri, Ahmed; Oberg, Kerby C.; Ros, Marian A.

    2014-01-01

    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. PMID:25166858

  7. Bioakumulasi logam berat Cu oleh Bacillus sp

    Directory of Open Access Journals (Sweden)

    Riesta Primaharinastiti

    2012-02-01

    Full Text Available The research was conducted to investigate the ability of Bacillus sp in accumulating Cu and how much it can be acumulated. Themedium used to growth the bacterium was Nutrient Broth and Atomic Absorption Spectrophotometry methods was used to assay theCu, both in the cells and medium. The result of this study showed that Bacillus sp incubated in the Nutrient Broth medium containing10 ppm of Cu, with continuous stirring in the room temperature was able to reduce Cu in the medium 8.912–12.623% and accumulateCu in the cell 0.1149–0.1400 %/mg cells. Based on this result, it is necessary to develop more studies to find out what factors thatinfluence the accumulation process and to optimize the bioprocess.

  8. 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.bioscience...dbc.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.bioscience...dbc.jp/kyushu-u/hg19/colo/SP2.Pluripotent_stem_cell.tsv http://dbarchive.biosciencedbc

  9. Superfield quantization in Sp(2) covariant formalism

    CERN Document Server

    Lavrov, P M

    2001-01-01

    The rules of the superfield Sp(2) covariant quantization of the arbitrary gauge theories for the case of the introduction of the gauging with the derivative equations for the gauge functional are generalized. The possibilities of realization of the expanded anti-brackets are considered and it is shown, that only one of the realizations is compatible with the transformations of the expanded BRST-symmetry in the form of super translations along the Grassmann superspace coordinates

  10. Carbon sp chains in graphene nanoholes

    Science.gov (United States)

    Castelli, Ivano E.; Ferri, Nicola; Onida, Giovanni; Manini, Nicola

    2012-03-01

    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 adopt a fair compromise of microscopic realism with a certain level of idealization in the model configurations, and predict a number of properties susceptible to comparison with experiment.

  11. Commercial technologies from the SP-100 program

    International Nuclear Information System (INIS)

    Truscello, V.C.; Fujita, T.; Mondt, J.F.

    1995-01-01

    For more than a decade, Jet Propulsion Labortory and Los Alamos have managed a multi-agency funded effort to develop a space reactor power system. This SP-100 Program has developed technologies required for space power systems that can be implemented in the industrial and commercial sectors to improve competitiveness in the global economy. Initial steps taken to transfer this technology from the laboratories to industrial and commercial entities within United States include: (1) identifying specific technologies having commercial potential; (2) distributing information describing the identified technologies and interacting with interested commercial and industrial entities to develop application-specific details and requirements; and (3) providing a technological data base that leads to transfer of technology or the forming of teaming arrangements to accomplish the transfer by tailoring the technology to meet application-specific requirements. SP-100 technologies having commercial potential encompass fabrication processes, devices, and components. Examples: a process for bonding refractory metals to graphite, a device to sense the position of an actuator and a component to enable rotating machines to operate without supplying lubrication (self-lubricating ball bearing). Shortly after the NASA Regional Technology Transfer Centers widely disseminated information covering SP-100 technologies, over one hundred expressions of interest were received, which indicate that there is a large potential benefit in transferring SP-100 technology. Interactions with industrial and commercial entities have identified a substantial need for creating teaming arrangements involving the interested entity and personnel from laboratories and their contractors, who have the knowledge and ability to tailor the technology to meet application-specific requirements. copyright 1995 American Institute of Physics

  12. Sterols from the Madagascar sponge Fascaplysinopsis sp.

    Science.gov (United States)

    Aknin, Maurice; Gros, Emmanuelle; Vacelet, Jean; Kashman, Yoel; Gauvin-Bialecki, Anne

    2010-12-17

    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, Δ(5), Δ(7) and Δ(5,7), 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 Δ(5,7) sterols is known to be unstable and easily photo-oxidized during storage and/or experiments to produce 5α,8α-epidioxy sterols. However, in this study, no 5α,8α-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 β-caroten bleaching assays.

  13. 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.

  14. Syrian hamsters (Mesocricetus auratus) with simultaneous intestinal Giardia sp., Spironucleus sp., and trichomonad infections.

    Science.gov (United States)

    Sheppard, Barbara J; Stockdale Walden, Heather D; Kondo, Hirotaka

    2013-11-01

    A commercial facility producing hamsters with a history of infection by dwarf tapeworm (Hymenolepis nana) submitted 15 animals for necropsy and postmortem parasitological and microscopic examination. No tapeworms were detected grossly or microscopically. Fecal examination including gastrointestinal mucosal smears demonstrated mixed intestinal bacteria and low numbers of Giardia sp. Histologic examination of small intestine demonstrated filling of the small intestinal crypts by large numbers of 7-9 µm × 3 µm, rod to crescent or teardrop-shaped flagellates consistent with Spironucleus sp. These organisms had two 1-µm, basophilic, oval nuclei and multiple superficial flagella-like structures. Much larger 10-15 µm × 8-10 µm, oval to pear-shaped organisms were also present in lower numbers and usually located with the crypts. These larger flagellates had multiple flagella and a basophilic rod-shaped nucleus. The larger flagellates included Giardia sp., which had an intimate interface with the surface of the mucosal epithelium, bilaterally symmetry, and binucleation. Lower numbers of trichomonads were also present and were distinguished by an undulating surface membrane and a single nucleus. The mucosa was hyperplastic and moderately inflamed. Although the tapeworm infection was resolved, diagnosis of multiple intestinal flagellates by fecal examination is complicated by the varying sensitivity and diagnostic accuracy of different types of fecal analysis for different flagellate types. Key differences in the morphology and location of the different types of flagellates as observed by histology of intestinal tissues provide important additional diagnostic information to distinguish trichomonads, Spironucleus sp., and Giardia sp.

  15. Borrelia bissettiae sp. nov. and Borrelia californiensis sp. nov. prevail in diverse enzootic transmission cycles

    Science.gov (United States)

    Margos, Gabriele; Lane, Robert S.; Fedorova, Natalia; Koloczek, Johannes; Piesman, Joseph; Hojgaard, Andrias; Sing, Andreas; Fingerle, Volker

    2018-01-01

    Two species of the genus Borrelia, Borrelia bissettiae sp. nov. and Borrelia californiensis sp. nov., were first described by Postic and co-workers on the basis of genetic analyses of several loci. Multilocus sequence analysis of eight housekeeping loci confirmed that these two Borrelia genomospecies are distinct members of the Borrelia burgdorferi sensu lato complex. B. bissettiae sp. nov. was initially described in transmission cycles involving Neotoma fuscipes wood rats and Ixodes pacificus ticks in California, and Neotoma mexicana and Ixodes spinipalpis in Colorado. The preferred host of B. californiensis sp. nov. appears to be the California kangaroo rat, Dipodomys californicus; Ixodes jellisoni, I. spinipalipis and I. pacificus ticks are naturally infected with it. Thus, the ecological associations of the two genomospecies and their genetic distance from all other known Borrelia genomospecies species justify their description as separate genomospecies: B. bissettiae sp. nov. (type strain DN127T=DSM 17990T= CIP 109136T) and B. californiensis (type strain CA446T=DSM 17989T=ATCC BAA-2689T). PMID:26813420

  16. 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%.

  17. SpAHA1 and SpSOS1 Coordinate in Transgenic Yeast to Improve Salt Tolerance.

    Directory of Open Access Journals (Sweden)

    Yang Zhou

    Full Text Available In plant cells, the plasma membrane Na+/H+ antiporter SOS1 (salt overly sensitive 1 mediates Na+ extrusion using the proton gradient generated by plasma membrane H+-ATPases, and these two proteins are key plant halotolerance factors. In the present study, two genes from Sesuvium portulacastrum, encoding plasma membrane Na+/H+ antiporter (SpSOS1 and H+-ATPase (SpAHA1, were cloned. Localization of each protein was studied in tobacco cells, and their functions were analyzed in yeast cells. Both SpSOS1 and SpAHA1 are plasma membrane-bound proteins. Real-time polymerase chain reaction (PCR analyses showed that SpSOS1 and SpAHA1 were induced by salinity, and their expression patterns in roots under salinity were similar. Compared with untransformed yeast cells, SpSOS1 increased the salt tolerance of transgenic yeast by decreasing the Na+ content. The Na+/H+ exchange activity at plasma membrane vesicles was higher in SpSOS1-transgenic yeast than in the untransformed strain. No change was observed in the salt tolerance of yeast cells expressing SpAHA1 alone; however, in yeast transformed with both SpSOS1 and SpAHA1, SpAHA1 generated an increased proton gradient that stimulated the Na+/H+ exchange activity of SpSOS1. In this scenario, more Na+ ions were transported out of cells, and the yeast cells co-expressing SpSOS1 and SpAHA1 grew better than the cells transformed with only SpSOS1 or SpAHA1. These findings demonstrate that the plasma membrane Na+/H+ antiporter SpSOS1 and H+-ATPase SpAHA1 can function in coordination. These results provide a reference for developing more salt-tolerant crops via co-transformation with the plasma membrane Na+/H+ antiporter and H+-ATPase.

  18. Copper resistance of different ectomycorrhizal fungi such as Pisolithus microcarpus, Pisolithus sp., Scleroderma sp. and Suillus sp.

    Directory of Open Access Journals (Sweden)

    R.F. Silva

    2013-01-01

    Full Text Available Environments contaminated with heavy metals negatively impact the living organisms. Ectomycorrhizal fungi have shown important role in these impacted sites. Thus, this study aimed to evaluate the copper-resistance of ectomycorrhizal fungi isolates Pisolithus microcarpus - UFSC-Pt116; Pisolithus sp. - UFSC-PT24, Suillus sp. - UFSM RA 2.8 and Scleroderma sp. - UFSC-Sc124 to different copper doses in solid and liquid media. The copper doses tested were: 0.00, 0.25, 0.5, 0.75, 1.0 and 1.25 mmol L-1 in the solid medium and 0.00, 0.32, 0.64 and 0.96 mmol L-1 in the liquid medium. Copper was amended as copper sulphate in order to supplement the culture medium MNM at pH 4.8, with seven replicates to each fungus-dose combination. The fungal isolates were incubated for 30 days at 28 °C. UFSC-Pt116 showed high copper-resistance such as accessed by CL50 determinations (concentration to reduce 50% of the growth as while as UFSC-PT24 displayed copper-resistance mechanism at 0.50 mmol L-1 in solid medium. The UFSC-PT24 and UFSC-Sc124 isolates have increased copper-resistance in liquid medium. The higher production of extracellular pigment was detected in UFSC-Pt116 cultures. The UFSC-Pt116 and UFSC-PT24 isolates showed higher resistance for copper and produced higher mycelium biomass than the other isolates. In this way, the isolates UFSG-Pt116 and UFSC-PT24 can be important candidates to survive in copper-contaminated areas, and can show important role in plants symbiosis in these contaminated sites.

  19. 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.

  20. Construction of human MASP-2-CCP1/2SP, CCP2SP, SP plasmid DNA nanolipoplexes and the effects on tuberculosis in BCG-infected mice.

    Science.gov (United States)

    Gao, Qi; Dong, Xinfang; Luo, Yanping; Zhang, Guochao; Shan, Jinyu; Wang, Qian; He, Qi; Zhang, Lifeng; Wang, Jingqiu; Zhu, Bingdong; Ma, Xingming

    2017-08-01

    The lectin pathway, one of the complement cascade systems, provides the primary line of defense against invading pathogens. The serine protease of MASP-2 plays an essential role in complement activation of the lectin pathway. The C-terminal segment of MASP-2 is comprised of the CCP1-CCP2-SP domains, and is the crucial catalytic segment. However, what is the effect of CCP1-CCP2-SP domains in controlling chronic infection is unknown. In order to evaluate the potential impact of CCP1-CCP2-SP domains on tuberculosis, we constructed the human MASP-2 CCP1/2SP, CCP2SP and SP recombinant plasmids, and delivered these plasmids by DNA-DOTAP:cholesterol cationic nanolipoplexes to BCG-infected mice. After 21 days post DNA-DOTAP:chol nanolipoplexes application, we analyzed bacteria loads of pulmonary, pathology of granuloma, lymphocyte subpopulations. The C3a, C4a and MASP-2 levels in serum were measured with enzyme-linked immunosorbent assays. Compared to the control group that received GFP DNA-DOTAP:chol nanolipoplexes, MASP-2 CCP1/2SP DNA-DOTAP:chol nanolipoplexes treated group showed significantly enlarged pulmonary granulomas lesion (P  0.05). These findings provided experimental evidence that MASP-2 CCP1/2SP DNA nanolipoplexes shown the negative efficacy in controlling Mycobacterium tuberculosis infection, and displayed a potential role of down-regulating T-cell-mediated immunity in tuberculosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Quality improvement on half-fin anchovy (Setipinna taty) fish sauce by Psychrobacter sp. SP-1 fermentation.

    Science.gov (United States)

    Zheng, Bin; Liu, Yu; He, Xiaoxia; Hu, Shiwei; Li, Shijie; Chen, Meiling; Jiang, Wei

    2017-10-01

    A method of improving fish sauce quality during fermentation was investigated. Psychrobacter sp. SP-1, a halophilic protease-producing bacterium, was isolated from fish sauce with flavor-enhancing properties and non-biogenic amine-producing activity. The performance of Psychrobacter sp. SP-1 in Setipinna taty fish sauce fermentation was investigated further. The inoculation of Psychrobacter sp. SP-1 did not significantly affect pH or NaCl concentration changes (P > 0.05), although it significantly increased total moderately halophilic microbial count, protease activity, total soluble nitrogen content and amino acid nitrogen content, and also promoted the umami taste and meaty aroma (P < 0.05). Furthermore, the inoculation of Psychrobacter sp. SP-1 significantly decreased total volatile basic nitrogen content and biogenic amines content (P < 0.05), which were regarded as harmful compounds in foods. The results of the present study demonstrate that Psychrobacter sp. SP-1 can be used as a potential starter culture for improving fish sauce quality by fermentation. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  2. Dominancy of Trichodesmium sp. in the Biawak Island

    Science.gov (United States)

    Prihadi, D. J.

    2018-03-01

    The Biawak Island is one of the small islands in West Java Province with an abundance of marine biological resources. This research was conducted to collect the primary producer zooplankton and water quality parameters. Direct observation is done by field surveys and measurement in situ for plankton and environmental parameters such as temperature, water transparency, water current, salinity, dissolved oxygen, and pH. Trichodesmium sp. was found dominance in where some other types of zooplankton were found in the area, like Scenedesmus sp., Sagitta sp., Acartia sp. also occurred. Further, the most abundance of Trichodesmium sp. was found in southern of Biawak Island where mangroves, coral and seagrass ecosystem provide nutrients which indirectly support the abundance of planktons. Trichodesmium sp. is plankton that can survive in water with minimum nutrient.

  3. The SP Theory of Intelligence: An Overview

    Directory of Open Access Journals (Sweden)

    J Gerard Wolff

    2013-08-01

    Full Text Available This article is an overview of the SP theory of intelligence, which aims to simplify and integrate concepts across artificial intelligence, mainstream computing and human perception and cognition, with information compression as a unifying theme. It is conceived of as a brain-like system that receives "New" information and stores some or all of it in compressed form as "Old" information; and it is realised in the form of a computer model, a first version of the SP machine. The matching and unification of patterns and the concept of multiple alignment are central ideas. Using heuristic techniques, the system builds multiple alignments that are "good" in terms of information compression. For each multiple alignment, probabilities may be calculated for associated inferences. Unsupervised learning is done by deriving new structures from partial matches between patterns and via heuristic search for sets of structures that are "good" in terms of information compression. These are normally ones that people judge to be "natural", in accordance with the "DONSVIC" principle—the discovery of natural structures via information compression. The SP theory provides an interpretation for concepts and phenomena in several other areas, including "computing", aspects of mathematics and logic, the representation of knowledge, natural language processing, pattern recognition, several kinds of reasoning, information storage and retrieval, planning and problem solving, information compression, neuroscience and human perception and cognition. Examples include the parsing and production of language with discontinuous dependencies in syntax, pattern recognition at multiple levels of abstraction and its integration with part-whole relations, nonmonotonic reasoning and reasoning with default values, reasoning in Bayesian networks, including "explaining away", causal diagnosis, and the solving of a geometric analogy problem.

  4. Early SP-100 flight mission designs

    International Nuclear Information System (INIS)

    Josloff, A.T.; Shepard, N.F.; Kirpich, A.S.; Murata, R.; Smith, M.A.; Stephen, J.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-kW e 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-kW 2 , 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-kW e in order to support recent studies by DOE/NASA for higher power early launch missions

  5. 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.

  6. SP-100 control drive assembly development

    Science.gov (United States)

    Gleason, Thomas; Gilchrist, A. Richard; Schuster, Gary

    1993-01-01

    The SP-100 is an electrical generating nuclear power system for space operation. This paper describes the nuclear reactor control systems and the methods used to assure reliable performance for the 10-year design life. Reliable performance is achieved by redundancy and by selecting highly reliable components and design features. Reliability is quantified by analysis using established reliability data. Areas lacking reliability data are identified for development testing. A specific development test description is provided as an example to demonstrate how this process is meeting the system reliability goals.

  7. ANCAMAN DARI NYAMUK Culex sp YANG TERABAIKAN

    Directory of Open Access Journals (Sweden)

    Zumrotus Sholichah

    2012-11-01

    Full Text Available Nyamuk Culex sp lebih menyukai meletakkan telurnya pada genangan air berpolutan tinggi, berkembang biak di air keruh dan lebih menyukai genangan air yang sudah lama daripada genangan air yang baru. Aktif menggigit pada malam hari. Tempat yang gelap, sejuk dan lembab merupakan tempat yang disukai untuk beristirahat. Nyamuk betina dewasa menggigit dengan abdomen terletak sejajar dengan permukaan induk semang yang sedang digigit.Gangguan yang ditimbulkan oleh nyamuk selain dapat menularkan penyakit juga dapat sangat mengganggu dengan dengungan dan gigitannya sehingga bagi orang-orang tertentu dapat menimbulkan phobi (entomopobhia serta dapat menyebabkan dermatitis dan urticaria.

  8. 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.

  9. Genome Sequence of Streptomyces sp. Strain Tü6071▿

    OpenAIRE

    Erxleben, Anika; Wunsch-Palasis, Julia; Grüning, Björn A.; Luzhetska, Marta; Bechthold, Andreas; Günther, Stefan

    2011-01-01

    Streptomyces sp. Tü6071 is a soil-dwelling bacterium which has a highly active isoprenoid biosynthesis. Isoprenoids are important precursors for biopharmaceutical molecules such as antibiotics or anticancer agents, e.g., landomycin. Streptomyces sp. Tü6071 produces the industrially important terpene glycosides phenalinolactones, which have antibacterial activity against several Gram-positive bacteria. The availability of the genome sequence of Streptomyces sp. Tü6071 allows for understanding ...

  10. Screening of biodiesel production from waste tuna oil (Thunnus sp.), seaweed Kappaphycus alvarezii and Gracilaria sp.

    Science.gov (United States)

    Alamsjah, Mochammad Amin; Abdillah, Annur Ahadi; Mustikawati, Hutami; Atari, Suci Dwi Purnawa

    2017-09-01

    Biodiesel has several advantages over solar. Compared to solar, biodiesel has more eco-friendly characteristic and produces lower greenhouse gas emissions. Biodiesel that is made from animal fats can be produced from fish oil, while other alternative sources from vegetable oils are seaweed Kappaphycus alvarezii and Gracilaria sp. Waste tuna oil (Thunnus sp.) in Indonesia is commonly a side product of tuna canning industries known as tuna precook oil; on the other hand, seaweed Gracilaria sp. and Kappaphycus alvarezii are commonly found in Indonesia's seas. Seaweed waste that was used in the present study was 100 kg and in wet condition, and the waste oil was 10 liter. The seaweed was extracted with soxhletation method that used n-hexane as the solvent. To produce biodiesel, trans esterification was performed on the seaweed oil that was obtained from the soxhletation process and waste tuna oil. Biodiesel manufactured from seaweed K. alvarezii obtained the best score in flash point, freezing point, and viscosity test. However, according to level of manufacturing efficiency, biodiesel from waste tuna oil is more efficient and relatively easier compared to biodiesel from waste K. alvarezii and Gracilaria sp.

  11. SHEAR STRENGTH IN THE GLUE LINE OF Eucalyptus sp. AND Pinus sp.WOOD

    Directory of Open Access Journals (Sweden)

    Juliana Jerásio Bianche

    Full Text Available ABSTRACT To evaluate the adhesive efficiency on the union of glued joints in a particular temperature and humidity conditions for a specified time the adhesive must be submitted to specific load tests, such as shear in the glue line. The objective of this study was to evaluate the shear strength in the glue line of Eucalyptus sp and Pinus sp.woods. Five adhesives (castor oil, sodium silicate, modified silicate, , PVA and resorcinol-formaldehyde, three weights (150 g/m2, 200 g/m2, and 250 g/m2 and two species (Eucalyptus sp. and Pinus sp. of wood were used. Twelve specimens were obtained from each repetition per treatment, corresponding to 108 specimens that were conditioned at a temperature of 23 ± 1°C and relative humidity of 50 ± 2%. The interaction between the weight and type of adhesive was significant for the shear strength in the glue line of eucalyptus wood. However, no interaction between the weight and the adhesive was found for pinus, only the isolated from the adhesive effect. Chemical bonds originated in the polymerization of resorcinol-formaldehyde adhesives and castor bi-component conferred upon these adhesives the greatest resistance in the glue line. Castor and resorcinol-formaldehyde adhesives showed the highest shear strength values in the line of glue and wood failure. Castor adhesive presented satisfactory performance for bonding of eucalyptus and pine woods.

  12. Genetic diversity in Fusarium oxysporum f.sp. dianthi and F. redolens f.sp. dianthi

    NARCIS (Netherlands)

    Baayen, R.P.; Dreven, van F.; Krijger, M.C.; Waalwijk, C.

    1997-01-01

    Pathogenic isolates were selected representing all known vegetative compatibility groups (VCGs) and races of Fusarium oxysporum sensu lato from Dianthus spp. On basis of differences in the internal transcribed spacer region of the ribosomal DNA, six VCGs were classified as F. oxysporum f.sp. dianthi

  13. 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.

  14. Sp(2) covariant quantisation of general gauge theories

    International Nuclear Information System (INIS)

    Vazquez-Bello, J.L.

    1994-11-01

    The Sp(2) covariant quantization of gauge theories is studied. The geometrical interpretation of gauge theories in terms of quasi principal fibre bundles Q(M s , G s ) is reviewed. It is then described the Sp(2) algebra of ordinary Yang-Mills theory. A consistent formulation of covariant Lagrangian quantisation for general gauge theories based on Sp(2) BRST symmetry is established. The original N = 1, ten dimensional superparticle is considered as an example of infinitely reducible gauge algebras, and given explicitly its Sp(2) BRST invariant action. (author). 18 refs

  15. 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.

  16. Lagenidium callinectes INFECTION ON ROTIFERS Brachionus sp.

    Directory of Open Access Journals (Sweden)

    Des Roza

    2007-06-01

    Full Text Available Milkfish, Chanos chanos and humpback grouper, Cromileptes altivelis hatcheries have developed at Gondol, Bali since 1995 and until now still rely on rotifers, the main natural food, supply. Recent problem on mass culture of rotifer, Brachionus sp. is harvest failure caused by fungus infection. Under light microscope, infected eggs and bodies of the rotifers was filled with numerous aseptate hyphae. Two isolates of fungi were isolated from rotifer eggs and carcass on June 21st, 2004 and on June 25th, 2004 obtained from milkfish and humpback grouper hatcheries at Gondol. Based on its morphological characteristics, the pathogenic fungus was identified as Lagenidium callinectes which grows optimally at 25°C and survives in 1.0%, 2.5%, and 5.0% NaCl as well as in 1.0% and 2.5% KCl. Both of the present isolates utilize only 8 out of 26 carbohydrates and derivatives tested as carbon, nutrition and energy sources. This finding is the first report on rotifer, Brachionus sp. infected with L. callinectes causing up to 100% mortality.

  17. Polyhydroxybutyrate by Streptomyces sp.: Production and characterization.

    Science.gov (United States)

    Krishnan, Sivakumar; Chinnadurai, Gandhi Shree; Perumal, Palani

    2017-11-01

    A total number of 20 actinomycetes isolates were isolated from soil sediments obtained from Semmancheri coastal areas of Bay of Bengal, India and they were qualitatively screened for the production of polyhydroxybutyrate (PHB) on a medium containing Sudan black stain. Nine of the 20 isolates produced PHB and the quantity of PHB produced varied from 1.79 to 4.26g -L . Among the positive isolates an actinomycete isolate which was identified as Streptomyces sp. through 16S rRNA sequencing analysis (Accession No: KF667247) produced relatively higher PHB than other positive isolates. Subsequently, the growth conditions were optimized for the maximum PHB production by the chosen organism. Attempt was also made to utilize natural carbon sources such as paddy straw, wheat bran, rice bran, sugarcane molasses and oil cake for the production of PHB in an attempt to reduce the cost production of PHB. The purified PHB was analyzed by Solid-State 13 C NMR, Fourier Transformed Infrared spectroscopy, Powder X-ray diffraction, Thermogravimetric Analysis, Scanning and Transmission Electron Microscopic analyses to determine the structure, crystallinity, purity and thermal stability. The present investigation has revealed that Streptomyces sp. could be a potential source for the production of PHB with desirable characteristics and could also be exploited for the industrial production. Copyright © 2017. Published by Elsevier B.V.

  18. Fluorescence Properties of Chlorella sp. Algae

    Directory of Open Access Journals (Sweden)

    Tibor Teplicky

    2017-01-01

    Full Text Available Water quality and its fast and reliable monitoring is the challenge of the future. Design of appropriate biosensors that would be capable of non-invasive identification of water pollution is an important prerequisite for such challenge. Chlorophylls are pigments, naturally presented in all plants that absorb light. The main forms of chlorophyll in algae are chlorophyll a and chlorophyll b, other pigments include xantophylls and beta-carotenes. Our aim was to characterize endogenous fluorescence of the Chlorella sp. algae, present naturally in drinking water. We recorded spatial, spectral and lifetime fluorescence distribution in the native algae. We noted that the fluorescence was evenly distributed in the algae cytosol, but lacked in the nucleus and reached maximum at 680-690 nm. Fluorescence decay of chlorella sp. was double-exponential, and clearly shorter than that of its isolated pigments. For the first time, fluorescence lifetime image of the algae is presented. Study of the fluorescence properties of algae is aimed at the improvement of water supply contamination detection and cleaning.

  19. Karakterisasi protease Bacillus sp. UGM5

    Directory of Open Access Journals (Sweden)

    Titik Purwati Widowati

    1999-07-01

    Full Text Available The objective of this experiment is to indentify the characters of proetease produced by Bacillus sp.UGM5.the protease secreted by Bacillus sp.UGM5 was first isolated,purified and then charactirezed.The crude enzyme has spesific actifity of 1.14 U/mg,however,the spesific activity of purified enzyme was increased by 23.8 times fold and recovery was 33.69%.The Page of nondenatured crude enzymes showes two type of proreases,however ,the SDS-Page of denatured purified enzyme showed four protein-bends with molecular weights of 55.5 kDa,18kDa respecetively.The optimum pH and temperature for the enzyme acrivity are 8.5 and 420C and belongs to serin protease type,with Km 3 X 10-3mM and Vmax 0.0890mM/30 minutes.The activity is not inhibited by Ca+2,Fe+2 and EDTA.

  20. UTILIZAÇÃO DE ADESIVO PVA EM COMPENSADOS DE Pinus sp. E Eucalyptus sp. / UTILIZATION OF PVA ADHESIVES IN Pinus sp. and Eucalyptus sp. PLYWOOD

    Directory of Open Access Journals (Sweden)

    C. I. De Campos

    2014-12-01

    Full Text Available Estudos sobre novos adesivos ou resinas para colagem de madeira e derivados estão sendo realizados com a intenção de diminuir o impacto ambiental sem alterar suas propriedades. Por este motivo, novas formulações de adesivos PVA (Acetato de Polivinila vêm sendo desenvolvidas. Este trabalho testou a utilização deste adesivo na produção de compensado de Eucalyptus sp. e Pinus sp., com tempo e temperatura de prensagem, respectivamente, de 10 minutos e90°C. Foram realizados os ensaios físicos de densidade, teor de umidade e absorção, e os ensaios mecânicos de flexão estática e de resistência ao cisalhamento na linha de cola, todos de acordo com as normas ABNT. Obtiveram-se bons resultados com relação à resistência ao cisalhamento na linha de cola, a qual foi superior para os adesivos PVA, se comparados com compensados produzidos com ureia-formaldeído e o fenol-formaldeído, enquanto que os resultados de MOE e MOR apresentaram-se inferiores em ambos os casos. 

  1. 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.

  2. First report of Giardia sp. and Cryptosporidium sp. in fecal samples in blue macaw (Anodorhynchus hyacinthinus in southern Brazil

    Directory of Open Access Journals (Sweden)

    Matheus Hillard Farret

    2010-09-01

    Full Text Available This study reports the gastrointestinal parasitism by Giardia sp. and Cryptosporidium sp. in blue macaw (Anodorhynchus hyacinthinus in the southern region of Brazil. Fecal samples of two species kept in captivity in the state of Rio Grande do Sul were analyzed by the direct smear method, centrifugal flotation technique with zinc sulfate and Kinyoun staining technique for research of parasites. Mixed infection by eggs of Capillaria, cysts of Giardia sp. and oocysts of Cryptosporidium sp. was observed. This is the first report this protozoa in blue macaw.

  3. 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.

  4. Microfungi on the Pandanaceae: Linocarpon lammiae sp. nov., L. siamensis sp. nov. and L. suthepensis sp. nov. are described with a key to Linocarpon species from the Pandanaceae.

    Science.gov (United States)

    Thongkantha, S; Lumyong, S; Lumyong, P; Whitton, S R; McKenzie, E H C; Hyde, K D

    2003-01-01

    Linocarpon species are reported from Pandanaceae in Australia, Brunei, Hong Kong, Nepal, New Zealand, Philippines, Seychelles, Thailand and Vanuatu. Linocarpon lammiae sp. nov. were collected on decaying leaves of Pandanus tectorius in Hong Kong. Linocarpon siamensis sp. nov. and L. suthepensis sp. nov. were collected from decaying leaves of P. penetrans in Thailand. These taxa are described, illustrated and compared with Linocarpon species with similar ascospore morphology and dimensions. Included are a synoptic table, which compares the new species to similar known species, and a dichotomous key to species of Linocarpon known from members of the Pandanaceae.

  5. 75 FR 42411 - Orders Finding That the SP-15 Financial Day-Ahead LMP Peak Daily Contract; SP-15 Financial Day...

    Science.gov (United States)

    2010-07-21

    ... COMMODITY FUTURES TRADING COMMISSION Orders Finding That the SP-15 Financial Day-Ahead LMP Peak Daily Contract; SP-15 Financial Day-Ahead LMP Off-Peak Daily Contract; SP-15 Financial Swap Real Time...-Peak Daily (``SQP'') contract; SP-15 Financial Swap Real Time LMP-Peak Daily (``SRP'') contract; NP-15...

  6. Kroyeria deetsi n.sp. (Kroyeriidae: Siphonostomatoida), a parasitic ...

    African Journals Online (AJOL)

    Kroyeria deetsi n.sp. (Kroyeriidae: Siphonostomatoida) is described from both sexes collected from the gills of spinner sharks, Carcharhinus brevipinna (Müller & Henle, 1839), captured in the Indian Ocean off the coast of South Africa. Kroyeria deetsi n.sp. can easily be distinguished from all of its congeners because the ...

  7. Evaluation of Cr (VI) remediation potential of Eichornia sp in ...

    African Journals Online (AJOL)

    Purpose: Evaluation of Cr (VI) removal by indigenous chromium resistant bacterial strains alone and in combination with Eichornia sp. Methods: Three chromium resistant bacterial strains S-4 Ochrobactrum grignonense, SF-5 Bacillus sp. and S-6 Ochrobactrum pseudogrignonenses were isolated from industrial effluent.

  8. Antibiotic Resistance in Salmonella sp and Escherichia coli Isolated ...

    African Journals Online (AJOL)

    Strains of Salmonella sp and E. coli isolated were significantly resistant to gentamicin, erythromycin, chloramphenicol, tetracycline, streptomycin, cefixine and ampicillin. Resistance to gentamicin was the least with 33-71% in Salmonella sp and 25-80% in E. coli. The level of drug resistance in these organisms is ascribed to ...

  9. Biochemical characterization of Fusarium oxysporum f . sp. cubense ...

    African Journals Online (AJOL)

    The Fusarium wilt caused by Fusarium oxyspoum f. sp. cubense (Foc) is a major biotic constraint for banana production. The characteristics of F. oxyspoum f. sp. cubense isolates were investigated using electrophoretic studies of isozyme and whole-cell protein. The morphological characteristics of the isolates were very ...

  10. LOCALIZATION OF SP22 ON HUMAN SPERM OF DIFFERING QUALITY

    Science.gov (United States)

    LOCALIZATION OF SP22 ON HUMAN SPERM OF DIFFERING QUALITY. AE Lavers*1, GR Klinefelter2, DW Hamilton1, KP Roberts1, 1University of Minnesota, Minneapolis, MN and 2US EPA, Research Triangle Park, NC. SP22 is a sperm membrane protein that has been implicated in sperm function d...

  11. Biochemical characterization of Fusarium oxysporum f. sp. cubense ...

    African Journals Online (AJOL)

    PRECIOUS

    2010-01-25

    Jan 25, 2010 ... Department of Studies in Biotechnology, University of Mysore, Manasagangotri, Mysore – 570 006, India. Accepted 24 November, 2009. The Fusarium wilt caused by Fusarium oxyspoum f. sp. cubense (Foc) is a major biotic constraint for banana production. The characteristics of F. oxyspoum f. sp. cubense ...

  12. Effects of phosphate solubilizing microorganisms and Rhizobium sp ...

    African Journals Online (AJOL)

    Effects of Phosphate solubilizing microorganisms ( Glomus intraradices, Pseudomonas putida, P. alcaligenes, P. aeruginosa (Pa28), A. awamori) and Rhizobium sp. was observed on the growth, nodulation yield and root-rot disease complex of chickpea under field condition. Inoculation of Rhizobium sp. caused a greater ...

  13. HANSENULA WICKERHAMII SP. N., A NEW YEAST FROM FINNISH SOIL

    Science.gov (United States)

    Capriotti, Augusto

    1961-01-01

    Capriotti, Augusto (l'Università di Perugia, Perugia, Italy). Hansenula wickerhamii sp. n., a new yeast from Finnish soil. J. Bacteriol. 82:259–360. 1961.—Hansenula wickerhamii sp. n. is described; it was isolated from a Finnish soil, and is named in honor of Lynferd J. Wickerham. Images PMID:13690638

  14. 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...

  15. Biofixation of carbon dioxide by Chlorococcum sp. in a ...

    African Journals Online (AJOL)

    In this study, Chlorococcum sp. was cultured in a photobioreactor with a polytetrafluoroethene membrane sparger (PTFE) to study CO2 biofixation and microalgae growth. Daily variations of dissolved oxygen (DO), pH and dissolved CO2 were analyzed during batch culture of Chlorococcum sp. in the photobioreactor.

  16. Production of mycelium and blastospores of sp. in submerged culture

    African Journals Online (AJOL)

    Hirsutella sp. was grown in four liquid media containing either casamino acids, corn steep liquor, collagen peptone or casein peptone. These media were inoculated with a 7 day-old culture of mycelia and blastospores of Hirsutella sp. and the cultures incubated with shaking at 250 rpm at 26°C. The media containing corn ...

  17. 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.

  18. Effects of phosphate solubilizing microorganisms and Rhizobium sp ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-04

    Aug 4, 2009 ... Effects of Phosphate solubilizing microorganisms (Glomus intraradices, Pseudomonas putida, P. alcaligenes, P. aeruginosa (Pa28), A. awamori) and Rhizobium sp. was observed on the growth, nodulation yield and root-rot disease complex of chickpea under field condition. Inoculation of. Rhizobium sp.

  19. Antioxidant activity of aqueous extract of a Tolypocladium sp ...

    African Journals Online (AJOL)

    Tolypocladium sp. Ts-1 was isolated from the fruiting body of a wild Cordyceps sinensis, one of the best known traditional Chinese medicine and health foods. The antioxidant activities of hot-water extracts from cultured mycelia of Tolypocladium sp. were assessed in different in vitro systems. The extracts showed ...

  20. Antioxidant activity of aqueous extract of a Tolypocladium sp. fungus ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-03

    Sep 3, 2008 ... Tolypocladium sp. Ts-1 was isolated from the fruiting body of a wild Cordyceps sinensis, one of the best known traditional Chinese medicine and health foods. The antioxidant activities of hot-water extracts from cultured mycelia of Tolypocladium sp. were assessed in different in vitro systems. The extracts ...

  1. Oncholaim~ jessicae n.sp. (Nematoda: Oncholaimidae) from fresh ...

    African Journals Online (AJOL)

    Oncholaim~ jessicae n.sp. (Nematoda: Oncholaimidae) from fresh water in the Transvaal. A. Coomans. Instituut voor Dierkunde, Rijksuniversiteit Gent, Gent, Belgium. J. Heyns. Department of Zoology, Rand Afrikaans University, Johannesburg. Oncholaimus jessicae n.sp. is described from several sites in the Blyde River ...

  2. 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

  3. Truncated recombinant human SP-D attenuates emphysema and type II cell changes in SP-D deficient mice.

    Science.gov (United States)

    Knudsen, Lars; Ochs, Matthias; Mackay, Rosemarie; Townsend, Paul; Deb, Roona; Mühlfeld, Christian; Richter, Joachim; Gilbert, Fabian; Hawgood, Samuel; Reid, Kenneth; Clark, Howard

    2007-10-03

    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. 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. 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. 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 characterized by decreased SP-D levels in the lung.

  4. Post-neonatal drop in alveolar SP-A expression

    DEFF Research Database (Denmark)

    Stray-Pedersen, Arne; Vege, Ashild; Stray-Pedersen, Asbjorg

    2008-01-01

    BACKGROUND: Surfactant protein A (SP-A) is synthesized in the lung and is a part of the innate immune system. The aim of this study was to evaluate the expression of SP-A in lung tissue from fetuses, infants, children and adults with special regard to sudden infant death syndrome (SIDS). METHODS......: A total of 160 cases were studied; 19 fetuses and neonates, 59 SIDS and 49 explained infant deaths below 1 year of age, 19 toddlers and 14 adults. Immunohistochemical detection of SP-A using monoclonal antibodies was performed by microscopy of lung tissue specimens collected at autopsy. A scoring system...... 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...

  5. SP-100 space reactor power system

    International Nuclear Information System (INIS)

    Kirpich, A.; Kruger, G.; Matteo, D.; Stephen, J.

    1990-01-01

    A generic flight system (GFS) design for a 100-kWe space reactor power (SP-100) system is presented. The design has evolved around issues such as the selection of a lithium liquid-metal-cooled reactor built of refractory metals and permitting operation in the range of 1300-1400 K; heat transport by lithium circulation using thermoelectrically driven liquid-metal pumps; thermoelectric power conversion; and waste heat rejection at approximately 800 K through lithium circulation to potassium heat pipe radiators. Various thermal-hydraulic analytical procedures have been utilized in the design of the reactor, ducting, hot-side and cold-side heat exchangers, circulating pumps, and heat pipe radiators. The physical and performance characteristics of the GFS and its power margins are estimated as a function of mission time

  6. Thermoelectric electromagnetic pump design for SP-100

    International Nuclear Information System (INIS)

    Collett, J.; Kugler, W.; Sinha, U.; Surjadi, T.

    1988-01-01

    This paper describes the design of the Thermoelectric Electromagnetic (TEM) pump used in the SP-100 space power system. The TEM pump is designed to pump liquid (molten) lithium (Li) coolant in the Primary Heat Transport Subsystem (PHTS) and Heat Rejection Subsystem (HRSS). The pump utilizes advanced Thermoelectric (TE) cells to generate electric current that induces magnetic flux in a Z-shaped magnetic structure. The electric current and magnetic flux pass through the liquid Li perpendicular to each other to create the pumping force. The TE cells are semiconductors located between rectangular ducts connected to the reactor hot PHTS piping and the cooler HRSS piping. The temperature difference (ΔT) across the TE cells generates the voltage to power the pump. The design provides a minimum mass, self-regulated pump, with no moving parts and self-powered by an internal temperature gradient

  7. SP-100 status and technology accomplishments

    International Nuclear Information System (INIS)

    Armijo, J.S.

    1989-01-01

    There are many space missions that require electric power in the 10-kW(electric) to 1-MW(electric) range. The SP-100 program will provide technology that demonstrates that a nuclear reactor heat source and passive thermoelectric conversion can reliably provide electrical power over this full range for 10 yr. Based on the generic flight system (GFS) design at 100 kW(electric), tests will be conducted to demonstrate that technologies required for the GFS have been validated. In addition, system-level tests will show that the GFS design and predictive capability to design at other power levels are well understood and meet an enveloping set of requirements. Technology and component testing has begun at General Electric (GE), its subcontractors, and several national laboratories. This paper reviews the significant progress made to date and major planned future tests with respect to the reference flight system, technology and component achievements, and nuclear assembly and integrated assembly tests

  8. Epitheliotropic lymphoma in a squirrel (Sciurus sp.).

    Science.gov (United States)

    Honnold, Shelley P; Arun, Iyampillai; Saturday, Greg; McLeod, Charles

    2007-09-01

    A 12-yr-old, intact male squirrel (Sciurus sp.) presented with a 15 mm-by-20 mm area of alopecia and plaque-like dermal thickening over the left caudolateral thorax. Routine diagnostic tests ruled out more common conditions that result in alopecia, such as dermatophytosis and acariasis. A punch biopsy was obtained under anesthesia and submitted for histopathologic evaluation. The diagnosis of epitheliotropic lymphoma was made, and follow-up surgical excision was performed. Histopathologic features were consistent with epitheliotropic lymphoma, and immunohistochemistry confirmed a T-cell origin. There was no local recurrence, new lesions, or evidence of metastasis 10 mo after surgical excision. To our knowledge, to date, epitheliotropic lymphoma has not been described in a squirrel.

  9. Chitinase Production by Streptomyces sp. ANU 6277

    Directory of Open Access Journals (Sweden)

    Kolla J.P. Narayana

    2009-12-01

    Full Text Available Chitinase production by a terrestrial Streptomyces sp. ANU 6277 was studied under sub-merged fermentation. Chitinase production started after 24 h of incubation and reached maximum levels after 60 h of cultivation. A high level of chitinase activity was observed in the culture medium with pH 6 at 35ºC. Culture medium amended with 1% chitin was found to be suitable for maximum production of chitinase. An optimum concentration of colloidal chitin for chitinase production was determined. Studies on the influence of additional carbon and nitrogen sources on chitinase production revealed that starch and yeast extract served as good carbon and nitrogen sources to enhance chitinase yield.Chitinase was purified from crude enzyme extract by single step gel filtration by Sephadex G-100. Purified chitinase of the strain exhibited a distinct protein band near 45 kDa by means of SDS-PAGE.

  10. Kinerja probiotik Bacillus sp. pada pendederan benih ikan lele Clarias sp. yang diinfeksi Aeromonas hydrophila

    Directory of Open Access Journals (Sweden)

    , Sukenda

    2016-12-01

    Full Text Available ABSTRACT This experiment was conducted to assess performance of Bacillus sp. probiotic on catfish juvenile Clarias sp. infected by Aeromonas hydrophila. The probiotic content in the diets were 0% (K+ and K-, 1%, and 2% in duplicates. This experiment used randomized design with four treatments and two replications. Juveniles with average body weight of 3.22±0.15 g/fish were reared in the 1.5×2.8×0.5 m3 pond with density of 800 fish/pond. Fish were reared for 30 days and fed three times a day at rate 8% of  total body weight. At day 31, catfish were challenged by A. hydrophila 0.1 mL (106 cfu/mL. Post infection observation was carried out ten days with density 10 fish/aquaria. The result showed that fish fed diet containing 2% probiotic gave the best probiotic performance with survival rate of catfish 83.33% after challenged, spesific growth rate 5.40%, and 0,75 of feed conversion ratio. The results of the blood profile showed significantly better results in the treatment of probiotics compared to the positive control after challenge test A. hydrophila. Probiotic Bacillus sp. has given as much as 2% on feed provides better performance on catfish juvenile. Keywords: probiotic, Bacillus sp., A. hydrophila, catfish juvenille, growth  ABSTRAK Penelitian ini bertujuan untuk menguji kinerja probiotik Bacillus sp. dalam pakan pada pendederan benih ikan lele Clarias sp. yang diinfeksi bakteri Aeromonas hydrophila. Penelitian ini menggunakan rancangan acak lengkap dengan empat perlakuan yaitu kandungan probiotik dalam pakan perlakuan yaitu 0% (K+ dan K-, 1%,  dan 2%, masing-masing dengan dua ulangan. Ikan lele yang digunakan memiliki bobot rata-rata 3,22±0,15 g/ekor, dipelihara dalam kolam terpal berukuran 1,5×2,8×0,5 m3 dengan kepadatan 800 ekor/kolam. Ikan dipelihara selama 30 hari dengan frekuensi pemberian pakan tiga kali sehari sebanyak 8% dari bobot tubuh ikan. Hari ke-31 benih lele diinjeksi bakteri A. hydrophila dosis 0,1 m

  11. Neorickettsia risticii, Rickettsia sp. and Bartonella sp. in Tadarida brasiliensis bats from Buenos Aires, Argentina.

    Science.gov (United States)

    Cicuttin, Gabriel L; De Salvo, María N; La Rosa, Isabel; Dohmen, Federico E Gury

    2017-06-01

    Bats are potential reservoirs of many vector-borne bacterial pathogens. The aim of the present study was to detect species of Anaplasma, Ehrlichia, Neorickettsia, Rickettsia, Borrelia and Bartonella in Brazilian free-tailed bats (Tadarida brasiliensis, Molossidae) from Buenos Aires city, Argentina. Between 2012 and 2013, 61 T. brasiliensis from urban areas of Buenos Aires city were studied. The samples were molecularly screened by PCR and sequencing. Five bats (8.2%) were positive to Neorickettsia risticii, one (1.6%) was positive to Rickettsia sp. and three bats (4.9%) to Bartonella sp. For molecular characterization, the positive samples were subjected to amplification and sequencing of a fragment of p51 gene for N. risticii, a fragment of citrate synthase gene (gltA) for Rickettsia genus and a fragment of gltA for Bartonella genus. Phylogenetic tree was constructed using the maximum-likelihood method. Phylogenetic analysis of N. risticii detect in our study revealed that it relates to findings in the USA West Coast; Rickettsia sp. detected is phylogenetically within R. bellii group, which also includes many other Rickettsia endosymbionts of insects; and Bartonella sp. found is related to various Bartonella spp. described in Vespertilionidae bats, which are phylogenetically related to Molossidae. Our results are in accordance to previous findings, which demonstrate that insectivorous bats could be infected with vector-borne bacteria representing a potential risk to public health. Future research is necessary to clarify the circulation of these pathogens in bats from Buenos Aires. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. From spent graphite to amorphous sp2+sp3 carbon-coated sp2 graphite for high-performance lithium ion batteries

    Science.gov (United States)

    Ma, Zhen; Zhuang, Yuchan; Deng, Yaoming; Song, Xiaona; Zuo, Xiaoxi; Xiao, Xin; Nan, Junmin

    2018-02-01

    Today, with the massive application of lithium ion batteries (LIBs) in the portable devices and electric vehicles, to supply the active materials with high-performances and then to recycle their wastes are two core issues for the development of LIBs. In this paper, the spent graphite (SG) in LIBs is used as raw materials to fabricate two comparative high-capacity graphite anode materials. Based on a microsurgery-like physical reconstruction, the reconstructed graphite (RG) with a sp2+sp3 carbon surface is prepared through a microwave exfoliation and subsequent spray drying process. In contrast, the neural-network-like amorphous sp2+sp3 carbon-coated graphite (AC@G) is synthesized using a self-reconfigurable chemical reaction strategy. Compared with SG and commercial graphite (CG), both RG and AC@G have enhanced specific capacities, from 311.2 mAh g-1 and 360.7 mAh g-1 to 409.7 mAh g-1 and 420.0 mAh g-1, at 0.1C after 100 cycles. In addition, they exhibit comparable cycling stability, rate capability, and voltage plateau with CG. Because the synthesis of RG and AC@G represents two typical physical and chemical methods for the recycling of SG, these results on the sp2+sp3 carbon layer coating bulk graphite also reveal an approach for the preparation of high-performance graphite anode materials derived from SG.

  13. Wnt-mediated down-regulation of Sp1 target genes by a transcriptional repressor Sp5

    Czech Academy of Sciences Publication Activity Database

    Fujimura, Naoko; Vacík, Tomáš; Machoň, Ondřej; Vlček, Čestmír; Scalabrin, S.; Speth, M.; Diep, D.; Krauss, S.; Kozmik, Zbyněk

    2007-01-01

    Roč. 282, č. 2 (2007), s. 1225-1237 ISSN 0021-9258 Institutional research plan: CEZ:AV0Z50520514 Keywords : Wnt -mediated signaling * Sp5 transcription factor * Sp1 target genes Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.581, year: 2007

  14. 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...

  15. Elevated expression and potential roles of human Sp5, a member of Sp transcription factor family, in human cancers

    International Nuclear Information System (INIS)

    Chen Yongxin; Guo Yingqiu; Ge Xijin; Itoh, Hirotaka; Watanabe, Akira; Fujiwara, Takeshi; Kodama, Tatsuhiko; Aburatani, Hiroyuki

    2006-01-01

    In this report, we describe the expression and function of human Sp5, a member of the Sp family of zinc finger transcription factors. Like other family members, the Sp5 protein contains a Cys2His2 zinc finger DNA binding domain at the C-terminus. Our experiments employing Gal4-Sp5 fusion proteins reveal multiple transcriptional domains, including a N-terminal activity domain, an intrinsic repressive element, and a C-terminal synergistic domain. Elevated expression of Sp5 was noted in several human tumors including hepatocellular carcinoma, gastric cancer, and colon cancer. To study the effects of the Sp5 protein on growth properties of human cancer cells and facilitate the identification of its downstream genes, we combined an inducible gene expression system with microarray analysis to screen for its transcriptional targets. Transfer of Sp5 into MCF-7 cells that expressed no detectable endogenous Sp5 protein elicited significant growth promotion activity. Several of the constitutively deregulated genes have been associated with tumorigenesis (CDC25C, CEACAM6, TMPRSS2, XBP1, MYBL1, ABHD2, and CXCL12) and Wnt/β-Catenin signaling pathways (BAMBI, SIX1, IGFBP5, AES, and p21 WAF1 ). This information could be utilized for further mechanistic research and for devising optimized therapeutic strategies against human cancers

  16. 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. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  17. 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.

  18. Kinetics of petroleum oil biodegradation by a consortium of three protozoan isolates (Aspidisca sp., Trachelophyllum sp. and Peranema sp.

    Directory of Open Access Journals (Sweden)

    L. Kachieng’a

    2017-09-01

    Full Text Available Petroleum oil is a complex mixture of substances, the majority of which are hydrocarbons; the latter represent an extremely important and heterogeneous group of compounds that find their way into water resources by anthropogenic or natural ways. The majority of toxic hydrocarbon components of petroleum are biodegradable, where bioremediation using microbial species has become an integral process for the restoration of oil-polluted areas. In this study, three bioremediation processes, namely natural attenuation, nutrient supplementation by adding glucose and biostimulation by adding Tween® 80, were carried out in various petroleum hydrocarbon concentrations in polluted water media using a consortium of three protozoan isolates (Aspidisca sp., Trachelophyllum sp. and Peranema sp.. A first-order kinetics model was fitted to the biodegradation data to evaluate the biodegradation rate and to determine the corresponding half-life time. First-order kinetics satisfactorily described the biodegradation of the petroleum-based contaminants under abiotic conditions. The results showed an increase in the percentage removal of petroleum oil at the lower petroleum concentrations and a gradual percentage decrease in removing petroleum oil residues occurred when there was an increase in the initial concentrations of the petroleum oil: 39%, 27%, 22%, 12%, 10% for various petroleum oil concentrations of 50, 100, 150, 200, 250 mg/L, respectively. A similar trend was also observed in the glucose-supplemented culture media where the reduction was 45% and 78% for petroleum concentrations of 250 mg/L and 50 mg/L, respectively. Biodegradation of between 33 and 90% was achieved at a Tween® 80 concentration of between 50 mg/L and 250 mg/L. The degradation rate constants for the natural attenuation process ranged between ≥0 to ≤0.50, ≥0 to ≤0.35, ≥0 to ≤0.25, ≥0 to ≤ 0.14 and ≥ 0 to ≤0.11 for petroleum oil concentrations varying from 50, 100, 150

  19. A sp2+sp3 hybridized carbon allotrope transformed from AB stacking graphyne and THD-graphene

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2018-01-01

    Full Text Available New carbon allotropes can be designed by combining sp, sp2 and sp3 three hybridization states. And the hybridization states or coordination numbers of carbon atoms can be changed by applying high pressure on carbon materials. In this study, a common high pressure phase (named as TBBC transformed from AB-stacking graphyne or THD-graphene is predicted. Its kinetic stability is examined using finite displacement method. We find that the sp2 and sp3 hybridized carbon atoms behave different vibration features at high frequency region. Both graphene-like and diamond-like vibration peaks occurs. Phase transition energy barriers from both graphyne and THD-graphene to TBBC are estimated. Electronic structure calculations show that the TBBC is an indirect semiconductor with a bandgap of 0.66 eV. The ideal tensile strength of TBBC is high in [0001] and [11¯00] directions, but is weak along [12¯10] direction.

  20. A sp2+sp3 hybridized carbon allotrope transformed from AB stacking graphyne and THD-graphene

    Science.gov (United States)

    Zhang, Yu; Shang, Jiacheng; Fu, Weida; Zeng, Li; Tang, Tao; Cai, Yingxiang

    2018-01-01

    New carbon allotropes can be designed by combining sp, sp2 and sp3 three hybridization states. And the hybridization states or coordination numbers of carbon atoms can be changed by applying high pressure on carbon materials. In this study, a common high pressure phase (named as TBBC) transformed from AB-stacking graphyne or THD-graphene is predicted. Its kinetic stability is examined using finite displacement method. We find that the sp2 and sp3 hybridized carbon atoms behave different vibration features at high frequency region. Both graphene-like and diamond-like vibration peaks occurs. Phase transition energy barriers from both graphyne and THD-graphene to TBBC are estimated. Electronic structure calculations show that the TBBC is an indirect semiconductor with a bandgap of 0.66 eV. The ideal tensile strength of TBBC is high in [0001] and [1 1 ¯ 00 ] directions, but is weak along [1 2 ¯ 10 ] direction.

  1. DAN IDENTIFIKASI PATOGEN POTENSIAL YANG MENGINFEKSI IKAN RAINBOW (Melanotaenia sp.

    Directory of Open Access Journals (Sweden)

    Lili Sholichah

    2014-03-01

    Full Text Available Pemeliharaan ikan rainbow (Melanotaenia sp. di Balai Penelitian dan Pengembangan Budidaya Ikan Hias selalu terjadi kematian secara bertahap mulai calon induk hingga proses pemijahan. Hal ini terjadi berulang kali sehingga ketersediaan induk Melanotaenia sp. sangat terancam. Ikan ini berasal dari Papua yang diperoleh mengandalkan penangkapan di alam. Tujuan dari penelitian ini adalah untuk menginventarisir dan mengidentifikasi berbagai patogen (parasit, jamur, bakteri potensial yang menginfeksi ikan rainbow yang dipelihara di dalam akuarium berukuran 50 cm x 50 cm x 50 cm dengan sistem aliran air stagnan. Tiga jenis rainbow yang dipelihara yaitu: rainbow Sungai Salawati, asal Sungai Sawiat, dan asal Danau Kurumoi. Setiap ikan masing-masing berjumlah 100 ekor dipelihara di akuarium dengan penambahan batu karang dan tanpa penambahan karang (kontrol ke dalam akuarium. Ikan diberi pakan sekenyangnya berupa jentik nyamuk dan cacing rambut beku setiap pagi dan sore hari. Sampling dilakukan secara random sebulan sekali dan secara unrandom setiap ada kejadian ikan sakit. Gejala klinis ikan yang sakit sebagai berikut: ikan berenang di permukaan dan menggosok-gosokkan badan di dinding akuarium, nafsu makan berkurang, gerakan berputar-putar, warna memudar menjadi putih, penekanan warna hitam pada sirip punggung dan perut meningkat, pendarahan pada perut, lendir berlebihan dan sangat berbau, serta sisik berdiri/terbuka. Diagnosa dan deteksi penyakit awal berupa pengamatan parasit baik ektoparasit maupun endoparasit, pengamatan dan isolasi jamur pada media selektif jamur, dan isolasi bakteri dilakukan untuk mengetahui jenis-jenis patogen yang menginfeksi ketiga jenis ikan rainbow. Selanjutnya dilakukan uji histologi dan analisa DNA beberapa patogen. Hasil pengamatan diperoleh patogen berupa parasit (Ichthyophthirius sp., Dactylogyrus sp., Gyrodactylus sp., dan Trichodina sp. dan bakteri (Aeromonas hydrophila, Acinetobacter sp

  2. Genetic polymorphism of horse serum protein 3 (SP3).

    Science.gov (United States)

    Juneja, R K; Sandberg, K; Kuryl, J; Gahne, B

    1989-01-01

    Two-dimensional agarose gel (pH 8.6)-horizontal polyacrylamide gel (pH 9.0) electrophoresis of horse serum samples, followed by general protein staining, revealed genetic polymorphism of an unidentified protein tentatively designated serum protein 3 (SP3). The SP3 fractions appeared distinctly when a 14% concentration of acrylamide was used in the separation gels. The 2-D mobilities of SP3 fractions were quite similar to that of albumin. Family data were consistent with the hypothesis that the observed SP3 phenotypes were controlled by four co-dominant, autosomal alleles (D, F, I, S). Evidence was provided that the F allele can be further divided into two alleles (F1 and F2); the mobilities of F1 and F2 variants were very similar. Each of the SP3 alleles gave rise to one fraction and each of the heterozygous types showed two fractions. More than 600 horses representing five different breeds (Swedish Trotter, North-Swedish Trotter, Thoroughbred, Arab and Polish Tarpan) were typed for SP3, and allele frequency estimates were calculated. SP3 was highly polymorphic in all breeds studied.

  3. 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.

  4. Pengaruh Perbedaan Konsentrasi Ekstrak Sargassum sp. dan Lama Penyimpanan terhadap Oksidasi Lemak pada Fillet Ikan Patin (Pangasius sp.

    Directory of Open Access Journals (Sweden)

    Fatin Hidayati

    2017-05-01

    Full Text Available ABSTRAK Ikan patin merupakan ikan air tawar yang mengandung lemak dan protein tinggi sehingga apabila dilakukan penyimpanan rentan terjadi oksidasi yang mengakibatkan ketengikan. Sargassum sp. dengan kandungan fenol dan flavonoid mampu menghambat terjadinya oksidasi pada fillet ikan patin. Penelitian ini bertujuan untuk mengetahui pengaruh perbedaan ekstrak Sargassum sp. dan lama penyimpanan dalam menghambat terjadinya oksidasi pada fillet ikan patin. Materi yang digunakan dalam penelitian ini adalah ekstrak Sargassum sp. dan fillet ikan patin. Metode penelitian yang digunakan adalah experimental laboratories dengan menggunakan Rancangan Acak Lengkap (RAL faktorial dengan 2 faktor yaitu konsentrasi ekstrak Sargassum sp. (0%, 1%, 1,5% dan 2% dan lama penyimpanan (hari ke-0, hari ke-2, hari ke-4, dan hari ke-6. Hasil penelitian menunjukkan bahwa perbedaan penambahan konsentrasi ekstrak Sargassum sp. dan lama penyimpanan memberikan pengaruh nyata terhadap nilai PV, nilai TBA, kadar lemak, kadar protein, kadar air serta organoleptik (P < 0,05. Hasil penelitian tahap I didapatkan rendemen Sargassum sp. dengan pelarut etanol 96% sebesar 1,39%, kandungan fenol 1,813%, flavonoid 0,278% dan aktivitas antioksidan 99,1659 ppm (kuat. Hasil penelitian tahap II didapatkan nilai PV berkisar antara 2,03 - 19,82 meq/kg, nilai TBA 0,63 - 6,72 mg.mal/kg. Konsentrasi 1,5% merupakan konsentrasi terbaik ekstrak Sargassum sp. dalam menghambat oksidasi lemak pada fillet ikan patin selama penyimpanan. Kata kunci: Antioksidan, Ekstrak Sargassum sp., Lama Penyimpanan, Oksidasi lemak, Fillet Ikan patin ABSTRACT Catfish is a freshwater fish that contain high fat and protein so that if its stored it will susceptible to oxidation process which leads to rancidity. Sargassum sp. with its phenolic and flavonoid content are able to inhibit the oxidation process in catfish fillet. This research was aimed to know the effects of different concentrations of Sargassum sp. extracts and

  5. Description of Pristina armata n. sp. (Clitellata: Naididae: Pristininae) from a carnivorous plant (Nepenthes sp.) in Borneo, Indonesia.

    Science.gov (United States)

    Schenková, Jana; Čermák, Václav

    2013-01-01

    A new clitellate species of Pristininae (Naididae), Pristina armata n. sp., found in the pitcher of the carnivorous plant Nepenthes sp., is reported from East Kalimantan, Indonesia. P. armata n. sp. is a very small clitellate, less than 1 mm long in fixed state, and without proboscis on the prostomium. Signs of reproduction by paratomy were observed, but the generic placement remains preliminary because sexually mature individuals were not found. P. armata n. sp. is characterized by giant hook-like dorsal chaetae at IV. The description of P. armata n. sp. was based on six fixed specimens of different size and stage of development. Noteworthy is the habitat of P. armata n. sp. in Nepenthes pitchers, this being the first clitellate species described from such a habitat. P. armata n. sp. may be a member of the nepenthebionts' community, realizing its life cycle inside the digestive fluid of the Nepenthes pitcher, or it belongs to nepenthephiles, species that commonly occur in this habitat but do not specialize on it.

  6. Plant growth promoting properties of Halobacillus sp. and Halomonas sp. in presence of salinity and heavy metals.

    Science.gov (United States)

    Desale, Prithviraj; Patel, Bhargav; Singh, Sukrit; Malhotra, Aakshi; Nawani, Neelu

    2014-08-01

    Salinity and heavy metal stress are challenging problems in agriculture. Here we report the plant growth promoting ability of three moderate halophiles, Halobacillus sp. ADN1, Halomonas sp. MAN5, and Halobacillus sp. MAN6, in presence of both salinity and heavy metal stress. Halobacillus sp. ADN1, Halomonas sp. MAN5, and Halobacillus sp. MAN6 can tolerate 25, 21, and 29% NaCl, respectively and grow in presence of 1 mM cobalt, cadmium, and nickel and 0.04 mM mercury and 0.03 mM silver. Halobacillus sp. ADN1, Halomonas sp. MAN5, and Halobacillus sp. MAN6 produced 152.5, 95.3, and 167.3 µg/ml indole acetic acid (IAA) and could solubilize 61, 53, and 75 parts per million (ppm) phosphate, respectively in the presence of 15% NaCl. The production of IAA and solubilization of phosphate was well retained in the presence of salinity and heavy metals like 1 mM cadmium, 0.7 mM nickel, 0.04 mM mercury, and 0.03 mM silver. Besides, the strains showed amylase and protease activities and could produce hydrogen cyanide and ammonia in presence of salinity and heavy metals. A mixture of three strains enhanced the root growth of Sesuvium portulacastrum under saline and heavy metal stress, where the root length increased nearly 4.5 ± 0.6 times and root dry weight increased 5.4 ± 0.5 times as compared to control. These strains can thus be useful in microbial assisted phytoremediation of polluted saline soils. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Lactobacillus oeni sp. nov., from wine.

    Science.gov (United States)

    Mañes-Lázaro, Rosario; Ferrer, Sergi; Rosselló-Mora, Ramón; Pardo, Isabel

    2009-08-01

    Ten Lactobacillus strains, previously isolated from different Bobal grape wines from the Utiel-Requena Origin Denomination of Spain, were characterized phylogenetically, genotypically and phenotypically. The 16S rRNA genes were sequenced and phylogenetic analysis showed that they form a tight phylogenetic clade that is closely related to reference strains Lactobacillus satsumensis NRIC 0604T, 'Lactobacillus uvarum' 8 and Lactobacillus mali DSM 20444T. DNA-DNA hybridization results confirmed the separation of the strains from other Lactobacillus species. Genotypically, the strains could be differentiated from their closest neighbours by 16S amplified rDNA restriction analysis and random amplified polymorphic DNA patterns. The strains were Gram-staining-positive, facultatively anaerobic rods that did not exhibit catalase activity. Phenotypically, they could be distinguished from their closest relatives by several traits such as their inabilities to grow at pH 3.3, to ferment sucrose, amygdalin and arbutin or to hydrolyse aesculin. The characteristics of the ten wine isolates suggest that they represent a novel species, for which the name Lactobacillus oeni sp. nov. is proposed. The type strain is 59bT (=CECT 7334T=DSM 19972T).

  8. Cellulomonas bogoriensis sp. nov., an alkaliphilic cellulomonad.

    Science.gov (United States)

    Jones, Brian E; Grant, William D; Duckworth, A W; Schumann, Peter; Weiss, Norbert; Stackebrandt, Erko

    2005-07-01

    An alkaliphilic, slightly halotolerant, chemo-organotrophic, Gram-positive, rod-shaped bacterium, strain 69B4(T), was isolated from the sediment of the littoral zone of Lake Bogoria, Kenya. Phylogenetically, it is a member of the genus Cellulomonas, showing less than 97.5 % sequence similarity to the type strains of other Cellulomonas species. The highest level of similarity, albeit moderate, was found with respect to Cellulomonas cellasea DSM 20118(T). Chemotaxonomic properties confirm the 16S rRNA gene-based generic affiliation, i.e. a DNA G+C content of 71.5 mol%, anteiso-C(15:0) and C(16:0) as the major fatty acids, MK-9(H(4)) as the major isoprenoid quinone, a peptidoglycan containing L-ornithine as the diamino acid and D-aspartic acid in the interpeptide bridge and phosphatidylglycerol as the only identified main polar lipid. The strain is aerobic to facultatively anaerobic, being capable of growth under strictly anaerobic conditions. Optimal growth occurs between pH values 9.0 and 10.0. On the basis of its distinct phylogenetic position and metabolic properties, strain 69B4(T) represents a novel species of the genus Cellulomonas, for which the name Cellulomonas bogoriensis sp. nov. is proposed. The type strain is 69B4(T) (=DSM 16987(T)=CIP 108683(T)).

  9. Preliminary SP-100/Stirling heat exchanger designs

    International Nuclear Information System (INIS)

    Schmitz, P.; Tower, L.; Blue, B.; Dunn, P.

    1994-01-01

    Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems

  10. Preliminary SP-100/Stirling heat exchanger designs

    International Nuclear Information System (INIS)

    Schmitz, P.; Tower, L.; Dawson, R.; Blue, B.; Dunn, P.

    1993-12-01

    Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor primary lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems

  11. Accomplishments and plans of SP-100 program

    International Nuclear Information System (INIS)

    Wright, W.E.

    1985-01-01

    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

  12. Phenotypic diversity of Xanthomonas sp. mangiferaeindicae.

    Science.gov (United States)

    Pruvost, O; Couteau, A; Perrier, X; Luisetti, J

    1998-01-01

    Carbohydrate utilization profiles by means of the API (Appareils et Procédés d'Identification) system and sensitivity to antibiotics and heavy metal salts of 68 Xanthomonas sp. mangiferaeindicae strains isolated in nine countries from mango (Mangifera indica L.) and other genera of the Anacardiaceae were examined to assess the variability of the taxon. The strains could be separated into 10 groups according to Ward clustering. Apigmented strains isolated from the pepper tree [syn. Brazilian pepper] (Schinus terebenthifolius Raddi) could not be clearly differentiated from most apigmented strains isolated from mango. Yellow-pigmented strains isolated from mango in Brazil and Reunion Island, apigmented strains isolated from mango in Brazil and from ambarella in the French West Indies, clustered in distinct groups. The results are consistent with those of other studies, based on isozyme analysis of esterase, phosphoglucomutase and superoxide dismutase, and hrp-RFLP analysis; they indicate the need for a comprehensive taxonomic evaluation of xanthomonads associated with Anacardiaceae.

  13. Kribbella sindirgiensis sp. nov. isolated from soil.

    Science.gov (United States)

    Ozdemir-Kocak, Fadime; Isik, Kamil; Saricaoglu, Salih; Saygin, Hayrettin; Inan-Bektas, Kadriye; Cetin, Demet; Guven, Kiymet; Sahin, Nevzat

    2017-12-01

    A Kribbella strain FSN23 T was isolated from soil sample which was collected from Caygoren Dam lakeside located in Sındırgı, Turkey. The isolate was investigated using a polyphasic approach consisting of numeric, chemotaxonomic and molecular analysis. The isolate indicated chemotaxonomic, morphological and phylogenetic properties associated with members of the genus Kribbella. Phylogenetic analysis based on the 16S rRNA sequence of the strain demonstrated that the strain forms a subclade with K. aluminosa HKI 0478 T and K. jejuensis HD9 T . The organism formed an extensively branched substrate and aerial hyphae which generated spiral chains of spores with smooth surfaces. The cell wall contained LL-diaminopimelic acid, and the whole cell sugars were glucose and ribose along with trace amounts of mannose. The polar lipids were identified as phosphatidylglycerol, diphosphatidylglycerol, four unidentified lipids and five unidentified polar lipids. The predominant menaquinone was MK-9(H 4 ). The major cellular fatty acids were anteiso-C 15:0 and iso-C 16:0 . Polyphasic taxonomy properties confirm that strain FSN23 T represents a novel Kribbella taxon distinguished from closely related type strains. Hence, strain FSN23 T (=KCTC 29220 T  = DSM 27082 T ) is proposed as the type strain of a novel species with the name Kribbella sindirgiensis sp. nov.

  14. Campylobacter iguaniorum sp. nov., isolated from reptiles.

    Science.gov (United States)

    Gilbert, Maarten J; Kik, Marja; Miller, William G; Duim, Birgitta; Wagenaar, Jaap A

    2015-03-01

    During sampling of reptiles for members of the class Epsilonproteobacteria, strains representing a member of the genus Campylobacter not belonging to any of the established taxa were isolated from lizards and chelonians. Initial amplified fragment length polymorphism, PCR and 16S rRNA sequence analysis showed that these strains were most closely related to Campylobacter fetus and Campylobacter hyointestinalis. A polyphasic study was undertaken to determine the taxonomic position of five strains. The strains were characterized by 16S rRNA and atpA sequence analysis, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry and conventional phenotypic testing. Whole-genome sequences were determined for strains 1485E(T) and 2463D, and the average nucleotide and amino acid identities were determined for these strains. The strains formed a robust phylogenetic clade, divergent from all other species of the genus Campylobacter. In contrast to most currently known members of the genus Campylobacter, the strains showed growth at ambient temperatures, which might be an adaptation to their reptilian hosts. The results of this study clearly show that these strains isolated from reptiles represent a novel species within the genus Campylobacter, for which the name Campylobacter iguaniorum sp. nov. is proposed. The type strain is 1485E(T) ( = LMG 28143(T) = CCUG 66346(T)). © 2015 IUMS.

  15. Taxonomic study of bacteria isolated from plants: proposal of Sphingomonas rosa sp. nov., Sphingomonas pruni sp. nov., Sphingomonas asaccharolytica sp. nov., and Sphingomonas mali sp. nov.

    Science.gov (United States)

    Takeuchi, M; Sakane, T; Yanagi, M; Yamasato, K; Hamana, K; Yokota, A

    1995-04-01

    The taxonomic positions of 10 strains of 3-ketolactose-forming bacteria which were isolated from the roots of plants (Rosa sp., Psychotria nairobiensis, Ardisia crispa, Prunus persica, and apple trees) were investigated. The DNA base compositions of these strains ranged from 64.0 to 65.7 mol%, the isoprenoid quinone of each strain was ubiquinone 10, 3-hydroxy fatty acids were lacking in the cellular fatty acids of these organisms, and all of the strains contained a sphingolipid with the long-chain base dihydrosphingosin. These are characteristics of the genus Sphingomonas. On the basis of morphological, physiological, and chemotaxonomic characteristics, together with DNA-DNA hybridization and 16S ribosomal DNA sequence comparison data, we propose the following four new species of the genus Sphingomonas: Sphingomonas rosa (type strain, IFO 15208) for the strains isolated from rose plants and formerly named [Agrobacterium rhizogenes]; Sphingomonas pruni (type strain, IFO 15498) for the strains isolated from Prunus persica; and Sphingomonas asaccharolytica (type strain, IFO 15499) and Sphingomonas mali (type strain, IFO 15500) for the strains isolated from apple trees. Two strains which were isolated from Psychotria nairobiensis and formerly named [Chromobacterium lividum] were identified as Sphingomonas yanoikuyae strains.

  16. Chryseobacterium solincola sp. nov., isolated from soil.

    Science.gov (United States)

    Benmalek, Yam; Cayol, Jean-Luc; Bouanane, Nabila A; Hacene, Hocine; Fauque, Guy; Fardeau, Marie-Laure

    2010-08-01

    A Gram-staining-negative, yellow-pigmented, strictly aerobic bacterium, designated strain 1YB-R12T, was isolated from a soil sample in western Algeria. The novel isolate was heterotrophic, chemoorganotrophic, halotolerant and psychrotolerant. The temperature and pH optima for growth were 28-30 degrees C and pH 7.3-8. The bacterium tolerated up to 6% (w/v) NaCl. Cells were non-motile, non-gliding and non-spore-forming, and were characterized by a variable morphological cycle. Flexirubin-type pigments were not detected. 16S rRNA gene sequence analysis showed that strain 1YB-R12T occupied a distinct lineage within the genus Chryseobacterium and shared highest sequence similarity with Chryseobacterium haifense LMG 24029T (96.5%). The DNA G+C content of strain 1YB-R12T was 40.9 mol%. The predominant cellular fatty acids were anteiso-C15:0 (41.4%) and iso-C15:0 (14.4%). On the basis of phenotypic properties and phylogenetic distinctiveness, strain 1YB-R12T is considered to represent a novel species of the genus Chryseobacterium, for which the name Chryseobacterium solincola sp. nov. is proposed. The type strain is 1YB-R12T (=DSM 22468T=CCUG 55604T).

  17. Production of biodiesel from Coelastrella sp. microalgae

    Science.gov (United States)

    Mansur, Dieni; Fitriady, Muhammad Arifuddin; Susilaningsih, Dwi; Simanungkalit, Sabar Pangihutan

    2017-11-01

    Microalgae have a wide area of usage and one of them it can be used for biodiesel production. In biodiesel production, lipids containing triglyceride or free fatty acid are converted into methyl ester through trans/esterification reactions. Lipids from microalgae can be extracted by acetone and dimethyl carbonate using homogenizer. Esterification of the lipids was investigated using various catalysts and source of methyl group. Activity of homogeneous catalyst such as HCl and H2SO4 and heterogeneous catalysts such as montmorillonit K-10 and ledgestone was investigated. Moreover, methanol and dimethyl carbonate as source of methyl group were also studied. Among of catalysts with methanol as source of methyl group, it was found that yield of crude biodiesel derived from Choelestrella Sp. microalgae was high over H2SO4 catalyst. On the other hand, over H2SO4 catalyst using dimethyl carbonate as source of methyl group, yield of crude biodiesel significant increase. However, FAME composition of crude biodiesel was high over HCl catalyst.

  18. Mycorrhizal dependency of laurel (Ocotea sp.)

    International Nuclear Information System (INIS)

    Sierra-Escobar, Jorge A; Castro Restrepo, Dagoberto; Osorio Vega, Walter

    2009-01-01

    A greenhouse experiment was carried out to determine the mycorrhizal dependency of laurel (>Ocotea sp.). In order to do this, a completely randomized experimental design was used, with six treatments in a factorial array of 3 x 2 and five repetitions. The treatments involved a combination of three Phosphorus (P) levels in soil solution (0.002, 0.02 and 0.2 mg L-1) and two levels of mycorrhizal inoculation, either inoculated or non-inoculated with Glomus aggregatum Schenck and Smith. The leaf P content as a function of time was used as an output variable. Shoot dry matter, shoot P content, mycorrhizal colonization of roots, and mycorrhizal dependence were measured at harvest. The results indicated that the leaf P content increased significantly when using the mycorrhizal inoculation in laurel at P level 0.2 mg L -1, but not in the other P levels, on some of the sampling days. Shoot dry weight and total plant P content did not increase at all levels of soil available P. Mycorrhizal dependency of laurel reached 28%, which allows this species to be classified as moderately dependent on mycorrhiza.

  19. The Growth of Monoraphidium sp. and Scenedesmus sp. Cells in the Presence of Thorium

    Directory of Open Access Journals (Sweden)

    Juliana Cristina de Queiroz

    2012-01-01

    Full Text Available Toxicity of thorium by Monoraphidium sp. and Scenedesmus sp. was studied. Microalgal cultures were inoculated in ASM-1 medium in presence and absence of thorium. Its effect was monitored by direct counting on Fuchs-Rosenthal chamber and with software. The toxicity of thorium over the species was observed for concentrations over 50.0 mg/L. After 30 days, Monoraphidium cells decreased their concentration from 4.23×106 to 4.27×105 and 8.57×105 cells/mL, in the presence of 50.0 and 100.0 mg/L of thorium, respectively. Scenedesmus sp. cells were more resistant to thorium: for an initial cell concentration of 7.65×104 cells/mL it was observed a change to 5.25×105 and 5.12×105 cells/mL, in the presence of thorium at 50.0 and 100.0 mg/L, respectively. This is an indication that low concentrations of the radionuclide favored the growth, and that Scenedesmus cells are more resistant to thorium than Monoraphidium cells. The software used for comparison with direct count method proved to be useful for the improvement of accuracy of the results obtained, a decrease in the uncertainty and allowed recording of the data. The presence of thorium suggests that low concentrations have a positive effect on the growth, due to the presence of the nitrate, indicating its potential for ecotoxicological studies.

  20. Aborto eqüino por Leptospira sp. Leptospira sp. as a cause of equine abortion

    Directory of Open Access Journals (Sweden)

    Caroline Argenta Pescador

    2004-02-01

    Full Text Available Descreve-se um caso de aborto eqüino por Leptospira sp. em um feto de 6 meses proveniente de um estabelecimento localizado próximo a Porto Alegre/RS. As lesões macroscópicas se caracterizaram por icterícia e hemorragias distribuídas difusamente sobre a pele, mucosa oral, tecido subcutâneo, pulmão, coração e sistema gastrintestinal. O fígado estava aumentado de tamanho, friável e de coloração amarelada. Os rins apresentavam hemorragias petequiais na superfície capsular e na superfície de corte observaram-se palidez da região cortical e medular. Cortes de rim e sistema nervoso central, corados por Warthin-Starry, revelaram a presença de espiroquetas nos túbulos, glomérulos e substância branca do encéfalo. Cultivo aeróbio de amostras de fígado e pulmão não revelaram crescimento bacteriano significativo. O teste de imunofluorescência direta para Leptospira sp. foi positivo e a sorologia fetal resultou numa titulação de 80 para o sorovar copenhageni e 40 para os sorovares icterohaemorragiae e pomona.This report describes an abortion on 6-month-old equine aborted fetus that has been caused by Leptospira sp. Main lesions included jaundice and hemorrhages diffusely scattered throughout the skin, oral mucosa, subcutaneous tissues, lungs, heart and gastrointestinal system. The liver was enlarged, pliable and yellow colored. The cortical and medullar of the kidneys were pale and petechial hemorrhages were present on the capsular surface. Warthin-Starry stained slices of the kidneys and central nervous system revealed the presence of spirochaetes within the tubules, glomeruli and white matter of the encephalo. Aerobic cultivation from samples of the liver and lungs were negative. The direct immunofluorescence test for Leptospira sp. was positive and the fetus’s serological test resulted titers of 80 against sorotype copenhageni and 40 against the sorotypes icterohaemorragiae and pomona.