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Sample records for arabidopsis requires crn

  1. An Oomycete CRN Effector Reprograms Expression of Plant HSP Genes by Targeting their Promoters.

    Science.gov (United States)

    Song, Tianqiao; Ma, Zhenchuan; Shen, Danyu; Li, Qi; Li, Wanlin; Su, Liming; Ye, Tingyue; Zhang, Meixiang; Wang, Yuanchao; Dou, Daolong

    2015-12-01

    Oomycete pathogens produce a large number of CRN effectors to manipulate plant immune responses and promote infection. However, their functional mechanisms are largely unknown. Here, we identified a Phytophthora sojae CRN effector PsCRN108 which contains a putative DNA-binding helix-hairpin-helix (HhH) motif and acts in the plant cell nucleus. Silencing of the PsCRN108 gene reduced P. sojae virulence to soybean, while expression of the gene in Nicotiana benthamiana and Arabidopsis thaliana enhanced plant susceptibility to P. capsici. Moreover, PsCRN108 could inhibit expression of HSP genes in A. thaliana, N. benthamiana and soybean. Both the HhH motif and nuclear localization signal of this effector were required for its contribution to virulence and its suppression of HSP gene expression. Furthermore, we found that PsCRN108 targeted HSP promoters in an HSE- and HhH motif-dependent manner. PsCRN108 could inhibit the association of the HSE with the plant heat shock transcription factor AtHsfA1a, which initializes HSP gene expression in response to stress. Therefore, our data support a role for PsCRN108 as a nucleomodulin in down-regulating the expression of plant defense-related genes by directly targeting specific plant promoters. PMID:26714171

  2. A Phytophthora sojae effector PsCRN63 forms homo-/hetero-dimers to suppress plant immunity via an inverted association manner.

    Science.gov (United States)

    Li, Qi; Zhang, Meixiang; Shen, Danyu; Liu, Tingli; Chen, Yanyu; Zhou, Jian-Min; Dou, Daolong

    2016-01-01

    Oomycete pathogens produce a large number of effectors to promote infection. Their mode of action are largely unknown. Here we show that a Phytophthora sojae effector, PsCRN63, suppresses flg22-induced expression of FRK1 gene, a molecular marker in pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI). However, PsCRN63 does not suppress upstream signaling events including flg22-induced MAPK activation and BIK1 phosphorylation, indicating that it acts downstream of MAPK cascades. The PsCRN63-transgenic Arabidopsis plants showed increased susceptibility to bacterial pathogen Pseudomonas syringae pathovar tomato (Pst) DC3000 and oomycete pathogen Phytophthora capsici. The callose deposition were suppressed in PsCRN63-transgenic plants compared with the wild-type control plants. Genes involved in PTI were also down-regulated in PsCRN63-transgenic plants. Interestingly, we found that PsCRN63 forms an dimer that is mediated by inter-molecular interactions between N-terminal and C-terminal domains in an inverted association manner. Furthermore, the N-terminal and C-terminal domains required for the dimerization are widely conserved among CRN effectors, suggesting that homo-/hetero-dimerization of Phytophthora CRN effectors is required to exert biological functions. Indeed, the dimerization was required for PTI suppression and cell death-induction activities of PsCRN63. PMID:27243217

  3. CRN Photo Information

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Photos of CRN stations and their immediate surroundings. Taken by engineering techs from NOAA's Atmospheric Turbulence and Diffusion Division (ATDD). Photos are...

  4. An Oomycete CRN Effector Reprograms Expression of Plant HSP Genes by Targeting their Promoters

    OpenAIRE

    Song, Tianqiao; MA, ZHENCHUAN; Shen, Danyu; Li, Qi; Li, Wanlin; Su, Liming; Ye, Tingyue; Zhang, Meixiang; Wang, Yuanchao; Dou, Daolong

    2015-01-01

    Oomycete pathogens produce a large number of CRN effectors to manipulate plant immune responses and promote infection. However, their functional mechanisms are largely unknown. Here, we identified a Phytophthora sojae CRN effector PsCRN108 which contains a putative DNA-binding helix-hairpin-helix (HhH) motif and acts in the plant cell nucleus. Silencing of the PsCRN108 gene reduced P. sojae virulence to soybean, while expression of the gene in Nicotiana benthamiana and Arabidopsis thaliana en...

  5. ABORTED GAMETOPHYTE 1 is required for gametogenesis in Arabidopsis.

    Science.gov (United States)

    Cui, Hong-Hui; Liao, Hong-Ze; Tang, Yu; Du, Xin-Yu; Chen, Li-Qun; Ye, De; Zhang, Xue-Qin

    2015-12-01

    In flowering plants, the male and female gametogenesis is a crucial step of sexual reproduction. Although many genes have been identified as being involved in the gametogenesis process, the genetic mechanisms underlying gametogenesis remains poorly understood. We reported here characterization of the gene, ABORTED GAMETOPHYTE 1 (AOG1) that is newly identified as essential for gametogenesis in Arabidopsis thaliana. AOG1 is expressed predominantly in reproductive tissues including the developing pollen grains and ovules. The AOG1 protein shares no significant amino acid sequence similarity with other documented proteins and is located mainly in nuclei of the cells. Mutation in AOG1 caused degeneration of pollen at the uninucleate microspore stage and severe defect in embryo sacs, leading to a significant reduction in male and female fertility. Furthermore, the molecular analyses showed that the aog1 mutant significantly affected the expression of several genes, which are required for gametogenesis. Our results suggest that AOG1 plays important roles in gametogenesis at the stage prior to pollen mitosis I (PMI) in Arabidopsis, possibly through collaboration with other genes. PMID:25693728

  6. MOL1 is required for cambium homeostasis in Arabidopsis.

    Science.gov (United States)

    Gursanscky, Nial Rau; Jouannet, Virginie; Grünwald, Karin; Sanchez, Pablo; Laaber-Schwarz, Martina; Greb, Thomas

    2016-05-01

    Plants maintain pools of pluripotent stem cells which allow them to constantly produce new tissues and organs. Stem cell homeostasis in shoot and root tips depends on negative regulation by ligand-receptor pairs of the CLE peptide and leucine-rich repeat receptor-like kinase (LRR-RLK) families. However, regulation of the cambium, the stem cell niche required for lateral growth of shoots and roots, is poorly characterized. Here we show that the LRR-RLK MOL1 is necessary for cambium homeostasis in Arabidopsis thaliana. By employing promoter reporter lines, we reveal that MOL1 is active in a domain that is distinct from the domain of the positively acting CLE41/PXY signaling module. In particular, we show that MOL1 acts in an opposing manner to the CLE41/PXY module and that changing the domain or level of MOL1 expression both result in disturbed cambium organization. Underlining discrete roles of MOL1 and PXY, both LRR-RLKs are not able to replace each other when their expression domains are interchanged. Furthermore, MOL1 but not PXY is able to rescue CLV1 deficiency in the shoot apical meristem. By identifying genes mis-expressed in mol1 mutants, we demonstrate that MOL1 represses genes associated with stress-related ethylene and jasmonic acid hormone signaling pathways which have known roles in coordinating lateral growth of the Arabidopsis stem. Our findings provide evidence that common regulatory mechanisms in different plant stem cell niches are adapted to specific niche anatomies and emphasize the importance of a complex spatial organization of intercellular signaling cascades for a strictly bidirectional tissue production. PMID:26991973

  7. Proline is required for male gametophyte development in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Mattioli Roberto

    2012-12-01

    Full Text Available Abstract Background In crosses between the proline-deficient mutant homozygous for p5cs1 and heterozygous for p5cs2 (p5cs1 p5cs2/P5CS2, used as male, and different Arabidopsis mutants, used as females, the p5cs2 mutant allele was rarely transmitted to the outcrossed progeny, suggesting that the fertility of the male gametophyte carrying mutations in both P5CS1 and P5CS2 is severely compromised. Results To confirm the fertility defects of pollen from p5cs1 p5cs2/P5CS2 mutants, transmission of mutant alleles through pollen was tested in two ways. First, the number of progeny inheriting a dominant sulfadiazine resistance marker linked to p5cs2 was determined. Second, the number of p5cs2/p5cs2 embryos was determined. A ratio of resistant to susceptible plantlets close to 50%, and the absence of aborted embryos were consistent with the hypothesis that the male gametophyte carrying both p5cs1 and p5cs2 alleles is rarely transmitted to the offspring. In addition, in reciprocal crosses with wild type, about 50% of the p5cs2 mutant alleles were transmitted to the sporophytic generation when p5cs1 p5cs2/P5CS2 was used as a female, while less than 1% of the p5cs2 alleles could be transmitted to the outcrossed progeny when p5cs1 p5cs2/P5CS2 was used as a male. Morphological and functional analysis of mutant pollen revealed a population of small, degenerated, and unviable pollen grains, indicating that the mutant homozygous for p5cs1 and heterozygous for p5cs2 is impaired in pollen development, and suggesting a role for proline in male gametophyte development. Consistent with these findings, we found that pollen from p5cs1 homozygous mutants, display defects similar to, but less pronounced than pollen from p5cs1 p5cs2/P5CS2 mutants. Finally, we show that pollen from p5cs1 p5cs2/P5CS2 plants contains less proline than wild type and that exogenous proline supplied from the beginning of another development can partially complement both morphological and

  8. Enhancing toughness of CrN coatings by Ni addition for safety-critical applications

    International Nuclear Information System (INIS)

    CrN is one of the most important transition metal nitrides, used as protective and anti-wear coating in modern engineering applications. However, CrN coatings are typically brittle and susceptible to catastrophic failure. In this paper, CrNiN coatings with differing Ni contents were deposited on tool steel substrates using a closed field unbalanced magnetron sputtering system. The effects of Ni addition on the microstructure and mechanical characteristics of CrN thin films were studied by combining nanoindentation tests with cross-sectional transmission electron microscopy. A columnar structure was observed in the CrN coating. With an increase in Ni content, the resultant columnar grains exhibited a high aspect ratio. Ni additions to CrN were found to enhance its damage resistance. Notably, the CrN thin film deformed mainly by intercolumnar shear sliding, whereas plastic deformation was favored in the CrNiN thin films exhibiting high aspect ratio columnar grains. More significantly, this change of microstructure with enhanced Ni content led to improved damage tolerance, manifested by a higher load required for crack formation upon a sharp contact (expressed as 1/HE2), and the plastic energy absorbed during nanoindentation

  9. Enhancing toughness of CrN coatings by Ni addition for safety-critical applications

    Energy Technology Data Exchange (ETDEWEB)

    Wo, Pui Ching, E-mail: amy.p.c.wo@wsu.edu [School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164 (United States); Munroe, Paul R. [School of Materials Science and Engineering, University of New South Wales, Sydney, UNSW 2052 (Australia); Jiang, Zhong-Tao [Physics and Nanotechnology, School of Engineering and Information Technology, Murdoch University, Murdoch 6150 (Australia); Zhou, Zhifeng; Li, Kwok Yan [Advanced Coatings Applied Research Laboratory, Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Xie, Zonghan [School of Mechanical Engineering, University of Adelaide, SA 5005 (Australia)

    2014-02-24

    CrN is one of the most important transition metal nitrides, used as protective and anti-wear coating in modern engineering applications. However, CrN coatings are typically brittle and susceptible to catastrophic failure. In this paper, CrNiN coatings with differing Ni contents were deposited on tool steel substrates using a closed field unbalanced magnetron sputtering system. The effects of Ni addition on the microstructure and mechanical characteristics of CrN thin films were studied by combining nanoindentation tests with cross-sectional transmission electron microscopy. A columnar structure was observed in the CrN coating. With an increase in Ni content, the resultant columnar grains exhibited a high aspect ratio. Ni additions to CrN were found to enhance its damage resistance. Notably, the CrN thin film deformed mainly by intercolumnar shear sliding, whereas plastic deformation was favored in the CrNiN thin films exhibiting high aspect ratio columnar grains. More significantly, this change of microstructure with enhanced Ni content led to improved damage tolerance, manifested by a higher load required for crack formation upon a sharp contact (expressed as 1/HE{sup 2}), and the plastic energy absorbed during nanoindentation.

  10. Cosmic Ray Nuclei (CRN) detector investigation

    Science.gov (United States)

    Meyer, Peter; Muller, Dietrich; Lheureux, Jacques; Swordy, Simon

    1991-01-01

    The Cosmic Ray Nuclei (CRN) detector was designed to measure elemental composition and energy spectra of cosmic radiation nuclei ranging from lithium to iron. CRN was flown as part of Spacelab 2 in 1985, and consisted of three basic components: a gas Cerenkov counter, a transition radiation detector, and plastic scintillators. The results of the experiment indicate that the relative abundance of elements in this range, traveling at near relativistic velocities, is similar to those reported at lower energy.

  11. BODYGUARD is required for the biosynthesis of cutin in Arabidopsis.

    Science.gov (United States)

    Jakobson, Liina; Lindgren, Leif Ove; Verdier, Gaëtan; Laanemets, Kristiina; Brosché, Mikael; Beisson, Fred; Kollist, Hannes

    2016-07-01

    The cuticle plays a critical role in plant survival during extreme drought conditions. There are, however, surprisingly, many gaps in our understanding of cuticle biosynthesis. An Arabidopsis thaliana T-DNA mutant library was screened for mutants with enhanced transpiration using a simple condensation spot method. Five mutants, named cool breath (cb), were isolated. The cb5 mutant was found to be allelic to bodyguard (bdg), which is affected in an α/β-hydrolase fold protein important for cuticle structure. The analysis of cuticle components in cb5 (renamed as bdg-6) and another T-DNA mutant allele (bdg-7) revealed no impairment in wax synthesis, but a strong decrease in total cutin monomer load in young leaves and flowers. Root suberin content was also reduced. Overexpression of BDG increased total leaf cutin monomer content nearly four times by affecting preferentially C18 polyunsaturated ω-OH fatty acids and dicarboxylic acids. Whole-plant gas exchange analysis showed that bdg-6 had higher cuticular conductance and rate of transpiration; however, plant lines overexpressing BDG resembled the wild-type with regard to these characteristics. This study identifies BDG as an important component of the cutin biosynthesis machinery in Arabidopsis. We also show that, using BDG, cutin can be greatly modified without altering the cuticular water barrier properties and transpiration. PMID:26990896

  12. CRN2 enhances the invasiveness of glioblastoma cells

    OpenAIRE

    Ziemann, Anja; Hess, Simon; Bhuwania, Ridhirama; Linder, Stefan; Kloppenburg, Peter; Noegel, Angelika A; Clemen, Christoph S.

    2013-01-01

    Background Movement of tumor cells involves dynamic remodeling of the actin cytoskeleton, which is regulated by actin binding proteins, such as CRN2 (synonyms: coronin 1C, coronin 3). In vitro, CRN2 participates in secretion, matrix degradation, protrusion formation, and cell migration. Furthermore, expression of CRN2 correlates with the malignant phenotype of human diffuse gliomas. CRN2's effects on actin polymerization and F-actin bundling are abolished by protein kinase 2 (CK2) dependent p...

  13. Requirement of proline synthesis during Arabidopsis reproductive development

    Directory of Open Access Journals (Sweden)

    Funck Dietmar

    2012-10-01

    Full Text Available Abstract Background Gamete and embryo development are crucial for successful reproduction and seed set in plants, which is often the determining factor for crop yield. Proline accumulation was largely viewed as a specific reaction to overcome stress conditions, while recent studies suggested important functions of proline metabolism also in reproductive development. Both the level of free proline and proline metabolism were proposed to influence the transition to flowering, as well as pollen and embryo development. Results In this study, we performed a detailed analysis of the contribution of individual proline biosynthetic enzymes to vegetative development and reproductive success in Arabidopsis. In contrast to previous reports, we found that pyrroline-5-carboxylate (P5C synthetase 2 (P5CS2 is not essential for sexual reproduction although p5cs2 mutant plants were retarded in vegetative development and displayed reduced fertility under long-day conditions. Single mutant plants devoid of P5CS1 did not show any developmental defects. Simultaneous absence of both P5CS isoforms resulted in pollen sterility, while fertile egg cells could still be produced. Expression of P5C reductase (P5CR was indispensable for embryo development but surprisingly not needed for pollen or egg cell fertility. The latter observation could be explained by an extreme stability of P5CR activity, which had a half-life time of greater than 3 weeks in vitro. Expression of P5CR-GFP under the control of the endogenous P5CR promoter was able to restore growth of homozygous p5cr mutant embryos. The analysis of P5CR-GFP-fluorescence in planta supported an exclusively cytoplasmatic localisation of P5CR. Conclusions Our results demonstrate that potential alternative pathways for proline synthesis or inter-generation transfer of proline are not sufficient to overcome a defect in proline biosynthesis from glutamate during pollen development. Proline biosynthesis through P5CS2 and P5

  14. ASK1 physically interacts with COI1 and is required for male fertility in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    戴良英; 徐领会; 黄大昉; 李栒; 罗宽; 官春云

    2002-01-01

    Jasmonates are a new class of plant hormones that play important roles in plant development and plant defense. The COI1 gene was previously shown to be required for jasmonate- regulated plant fertility and defense. We demonstrated for the first time that COI1 interacts with the Arabidopsis SKP1-LIKE1 (ASK1) to form a complex that is required for jasmonate action in planta. Functional analysis by antisense strategy showed that ASK1 is involved in male fertility.

  15. The glutaredoxin ATGRXS13 is required to facilitate Botrytis cinerea infection of Arabidopsis thaliana plants

    OpenAIRE

    Camera, Sylvain La; L’Haridon, Floriane; Astier, Jérémy; Zander, Mark; Abou-Mansour, Eliane; Page, Gonzague; Thurow, Corinna; Wendehenne, David; Gatz, Christiane; Métraux, Jean-Pierre; Lamotte, Olivier

    2011-01-01

    Botrytis cinerea is a major pre- and post-harvest necrotrophic pathogen with a broad host range that causes substantial crop losses. The plant hormone jasmonic acid (JA) is involved in the basal resistance against this fungus. Despite basal resistance, virulent strains of B. cinerea can cause disease on Arabidopsis thaliana and virulent pathogens can interfere with the metabolism of the host in a way to facilitate infection of the plant. However, plant genes that are required by the pathogen ...

  16. Seed germination of GA-insensitive sleepy1 mutants does not require RGL2 protein disappearance in Arabidopsis

    Science.gov (United States)

    Seed germination is a complex developmental process regulated by phytohormones. The phytohormone abscisic acid (ABA) inhibits seed germination, whereas gibberellin (GA) stimulates seed germination. In tomato and Arabidopsis, GA is clearly required for seed germination. Recent evidence suggests tha...

  17. Characterisation of cell death inducing Phytophthora capsici CRN effectors suggests diverse activities in the host nucleus

    Directory of Open Access Journals (Sweden)

    Remco eStam

    2013-10-01

    Full Text Available Plant-Microbe interactions are complex associations that feature recognition of Pathogen Associated Molecular Patterns by the plant immune system and dampening of subsequent responses by pathogen encoded secreted effectors. With large effector repertoires now identified in a range of sequenced microbial genomes, much attention centres on understanding their roles in immunity or disease. These studies not only allow identification of pathogen virulence factors and strategies, they also provide an important molecular toolset suited for studying immunity in plants. The Phytophthora intracellular effector repertoire encodes a large class of proteins that translocate into host cells and exclusively target the host nucleus. Recent functional studies have implicated the CRN protein family as an important class of diverse effectors that target distinct subnuclear compartments and modify host cell signalling. Here, we characterised three necrosis inducing CRNs and show that there are differences in the levels of cell death. We show that only expression of CRN20_624 has an additive effect on PAMP induced cell death but not AVR3a induced ETI. Given their distinctive phenotypes, we assessed localisation of each CRN with a set of nuclear markers and found clear differences in CRN subnuclear distribution patterns. These assays also revealed that expression of CRN83_152 leads to a distinct change in nuclear chromatin organisation, suggesting a distinct series of events that leads to cell death upon over-expression. Taken together, our results suggest diverse functions carried by CRN C-termini, which can be exploited to identify novel processes that take place in the host nucleus and are required for immunity or susceptibility.

  18. CESA5 Is Required for the Synthesis of Cellulose with a Role in Structuring the Adherent Mucilage of Arabidopsis Seeds

    OpenAIRE

    Sullivan, Stuart; Ralet, Marie-Christine; Berger, Adeline; Diatloff, Eugene; Bischoff, Volker; Gonneau, Martine; Marion-Poll, Annie

    2011-01-01

    Imbibed Arabidopsis (Arabidopsis thaliana) seeds are encapsulated by mucilage that is formed of hydrated polysaccharides released from seed coat epidermal cells. The mucilage is structured with water-soluble and adherent layers, with cellulose present uniquely in an inner domain of the latter. Using a reverse-genetic approach to identify the cellulose synthases (CESAs) that produce mucilage cellulose, cesa5 mutants were shown to be required for the correct formation of these layers. Expressio...

  19. crnA encodes a nitrate transporter in Aspergillus nidulans

    OpenAIRE

    Unkles, S.E.; Hawker, K L; Grieve, C; Campbell, E I; Montague, P.; Kinghorn, J R

    1995-01-01

    The nucleotide sequence of the Aspergillus nidulans crnA gene for the transport of the anion nitrate has been determined. The crnA gene specifies a predicted polypeptide of 483 amino acids (molecular weight 51,769). A hydropathy plot suggests that this polypeptide has 10 membrane-spanning helices with an extensive hydrophilic region between helices six and seven. No striking homology was observed between the crnA protein and other reported membrane proteins of either prokaryotic or eukaryotic...

  20. The Arabidopsis MutS homolog AtMSH5 is required for normal meiosis

    Institute of Scientific and Technical Information of China (English)

    Xiaoduo Lu; Xiaolin Liu; Lizhe An; Wei Zhang; Jian Sun; Huijuan Pei; Hongyan Meng; Yunliu Fan; Chunyi Zhang

    2008-01-01

    MSH5,a member of the MutS homolog DNA mismatch repair protein family,has been shown to be required for proper homologous chromosome recombination in diverse organisms such as mouse,budding yeast and Caenorhabditis elegans.In this paper,we show that a mutant Arabidopsis plant carrying the putative disrupted AtMSH5 gene exhibits defects during meiotic division,producing a proportion of nonviable pollen grains and abnormal embryo sacs,and thereby leading to a decrease in fertility.AtMSH5 expression is confined to meiotic floral buds,which is consistent with a possible role during meiosis.Cytological analysis of male meiosis revealed the presence of numerous univalents from diplotene to metaphase I,which were associated with a great reduction in chiasma frequencies.The average number of residual chiasmata in the mutant is reduced to 2.54 per meiocyte,which accounts for~25% of the amount in the wild type.Here,quantitative cytogenetical analysis reveals that the residual chiasmata in Atmsh5 mutants are randomly distributed among meiocytes,suggesting that AtMSH5 has an essential role during interferencesensitive chiasma formation.Taken together,the evidence indicates that AtMSH5 promotes homologous recombination through facilitating chiasma formation during prophase I in Arabidopsis.

  1. The Arabidopsis Vacuolar Sorting Receptor1 Is Required for Osmotic Stress-Induced Abscisic Acid Biosynthesis

    KAUST Repository

    Wang, Zhen-Yu

    2014-11-21

    Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1.

  2. The Arabidopsis Golgi-localized GDP-L-fucose transporter is required for plant development.

    Science.gov (United States)

    Rautengarten, Carsten; Ebert, Berit; Liu, Lifeng; Stonebloom, Solomon; Smith-Moritz, Andreia M; Pauly, Markus; Orellana, Ariel; Scheller, Henrik Vibe; Heazlewood, Joshua L

    2016-01-01

    Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1 (GFT1), an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rhamnogalacturonan II. Furthermore, these lines display reduced L-fucose content in N-glycan structures accompanied by severe developmental growth defects. We conclude that GFT1 is the major nucleotide sugar transporter for import of GDP-L-fucose into the Golgi and is required for proper plant growth and development. PMID:27381418

  3. Multiple receptor complexes assembled for transmitting CLV3 signaling in Arabidopsis

    OpenAIRE

    Zhu, Yingfang; Wan, Yinglang; Lin, Jinxing

    2010-01-01

    In Arabidopsis, the feedback regulatory loop between CLAVATA3 (CLV3) signaling pathway and transcription factor, WUSCHEL (WUS) plays a significant role in shoot apical meristems (SAM) maintenance. Previously, CLV1/CLV2 heterodimers were supposed to perceive and transmit CLV3 signaling. Recent genetic analysis isolated a novel receptor kinase, CORYNE (CRN), which was found to be involved in the CLV3 pathway. Therefore, new hypothesis was put forward that CRN probably acts with CLV2 to transmit...

  4. Identification and Characterisation CRN Effectors in Phytophthora capsici Shows Modularity and Functional Diversity

    OpenAIRE

    Stam, Remco; Jupe, Julietta; Howden, Andrew J. M.; Morris, Jenny A.; Boevink, Petra C.; Hedley, Pete E; Huitema, Edgar

    2013-01-01

    Phytophthora species secrete a large array of effectors during infection of their host plants. The Crinkler (CRN) gene family encodes a ubiquitous but understudied class of effectors with possible but as of yet unknown roles in infection. To appreciate CRN effector function in Phytophthora, we devised a simple Crn gene identification and annotation pipeline to improve effector prediction rates. We predicted 84 full-length CRN coding genes and assessed CRN effector domain diversity in sequence...

  5. DRB2 is required for microRNA biogenesis in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Andrew L Eamens

    Full Text Available BACKGROUND: The Arabidopsis thaliana (Arabidopsis DOUBLE-STRANDED RNA BINDING (DRB protein family consists of five members, DRB1 to DRB5. The biogenesis of two developmentally important small RNA (sRNA species, the microRNAs (miRNAs and trans-acting small interfering RNAs (tasiRNAs by DICER-LIKE (DCL endonucleases requires the assistance of DRB1 and DRB4 respectively. The importance of miRNA-directed target gene expression in plant development is exemplified by the phenotypic consequence of loss of DRB1 activity (drb1 plants. PRINCIPAL FINDINGS: Here we report that the developmental phenotype of the drb235 triple mutant plant is the result of deregulated miRNA biogenesis in the shoot apical meristem (SAM region. The expression of DRB2, DRB3 and DRB5 in wild-type seedlings is restricted to the SAM region. Small RNA sequencing of the corresponding tissue of drb235 plants revealed altered miRNA accumulation. Approximately half of the miRNAs detected remained at levels equivalent to those of wild-type plants. However, the accumulation of the remaining miRNAs was either elevated or reduced in the triple mutant. Examination of different single and multiple drb mutants revealed a clear association between the loss of DRB2 activity and altered accumulation for both the elevated and reduced miRNA classes. Furthermore, we show that the constitutive over-expression of DRB2 outside of its wild-type expression domain can compensate for the loss of DRB1 activity in drb1 plants. CONCLUSIONS/SIGNIFICANCE: Our results suggest that in the SAM region, DRB2 is both antagonistic and synergistic to the role of DRB1 in miRNA biogenesis, adding an additional layer of gene regulatory complexity in this developmentally important tissue.

  6. Structure and corrosion properties of PVD Cr-N coatings

    CERN Document Server

    Liu, C; Ziegele, H; Leyland, A; Matthews, A

    2002-01-01

    PVD Cr-N coatings produced by physical vapor deposition (PVD) are increasingly used for mechanical and tribological applications in various industrial sectors. These coatings are particularly attractive for their excellent corrosion resistance, which further enhances the lifetime and service quality of coated components. PVD Cr-N coated steels in an aqueous solution are usually corroded by galvanic attack via through-coating 'permeable' defects (e.g., pores). Therefore, the corrosion performance of Cr-N coated steel is determined by a number of variables of the coating properties and corrosive environment. These variables include: (i) surface continuity and uniformity; (ii) through-coating porosity; (iii) film density and chemical stability; (iv) growth stresses; (v) interfacial and intermediate layers; (vi) coating thickness; (vii) coating composition; and (viii) substrate properties. In this article, PVD Cr-N coatings were prepared, by electron-beam PVD and sputter deposition, with different compositions, t...

  7. Investigation on Microblasting Applied to CrN Coatings

    OpenAIRE

    Lorenzo Montesano; Annalisa Pola; Marcello Gelfi; Giovina Marina La Vecchia

    2016-01-01

    A microblasting treatment carried out on CrN coated samples was studied to investigate the induced effect on corrosion and wear resistance. CrN coating was deposited through Cathodic Arc Evaporation technique on quenched and tempered steel. The properties of the coating were studied by hardness measurements, scratch, potentiodynamic, and pin-on-disk tests. The results show that microblasting reduces the corrosion resistance while improving the wear behavior.

  8. A "Whirly" transcription factor is required for salicylic acid-dependent disease resistance in Arabidopsis.

    Science.gov (United States)

    Desveaux, Darrell; Subramaniam, Rajagopal; Després, Charles; Mess, Jean-Nicholas; Lévesque, Caroline; Fobert, Pierre R; Dangl, Jeffery L; Brisson, Normand

    2004-02-01

    Transcriptional reprogramming is critical for plant disease resistance responses; its global control is not well understood. Salicylic acid (SA) can induce plant defense gene expression and a long-lasting disease resistance state called systemic acquired resistance (SAR). Plant-specific "Whirly" DNA binding proteins were previously implicated in defense gene regulation. We demonstrate that the potato StWhy1 protein is a transcriptional activator of genes containing the PBF2 binding PB promoter element. DNA binding activity of AtWhy1, the Arabidopsis StWhy1 ortholog, is induced by SA and is required for both SA-dependent disease resistance and SA-induced expression of an SAR response gene. AtWhy1 is required for both full basal and specific disease resistance responses. The transcription factor-associated protein NPR1 is also required for SAR. Surprisingly, AtWhy1 activation by SA is NPR1 independent, suggesting that AtWhy1 works in conjunction with NPR1 to transduce the SA signal. Our analysis of AtWhy1 adds a critical component to the SA-dependent plant disease resistance response. PMID:14960277

  9. Temporal and spatial requirement of EMF1 activity for Arabidopsis vegetative and reproductive development.

    Science.gov (United States)

    Sánchez, Rosario; Kim, Minjung Y; Calonje, Myriam; Moon, Yong-Hwan; Sung, Z Renee

    2009-07-01

    EMBRYONIC FLOWER (EMF) genes are required to maintain vegetative development via repression of flower homeotic genes in Arabidopsis. Removal of EMF gene function caused plants to flower upon germination, producing abnormal and sterile flowers. The pleiotropic effect of emf1 mutation suggests its requirement for gene programs involved in diverse developmental processes. Transgenic plants harboring EMF1 promoter::glucuronidase (GUS) reporter gene were generated to investigate the temporal and spatial expression pattern of EMF1. These plants displayed differential GUS activity in vegetative and flower tissues, consistent with the role of EMF1 in regulating multiple gene programs. EMF1::GUS expression pattern in emf mutants suggests organ-specific auto-regulation. Sense- and antisense (as) EMF1 cDNA were expressed under the control of stage- and tissue-specific promoters in transgenic plants. Characterization of these transgenic plants showed that EMF1 activity is required in meristematic as well as differentiating tissues to rescue emf mutant phenotype. Temporal removal or reduction of EMF1 activity in the embryo or shoot apex of wild-type seedlings was sufficient to cause early flowering and terminal flower formation in adult plants. Such reproductive cell memory is reflected in the flower MADS-box gene activity expressed prior to flowering in these early flowering plants. However, temporal removal of EMF1 activity in flower meristem did not affect flower development. Our results are consistent with EMF1's primary role in repressing flowering in order to allow for vegetative growth. PMID:19825645

  10. A cellulose synthase-like protein is required for osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Zhu, Jianhua

    2010-04-16

    Osmotic stress imposed by soil salinity and drought stress significantly affects plant growth and development, but osmotic stress sensing and tolerance mechanisms are not well understood. Forward genetic screens using a root-bending assay have previously identified salt overly sensitive (sos) mutants of Arabidopsis that fall into five loci, SOS1 to SOS5. These loci are required for the regulation of ion homeostasis or cell expansion under salt stress, but do not play a major role in plant tolerance to the osmotic stress component of soil salinity or drought. Here we report an additional sos mutant, sos6-1, which defines a locus essential for osmotic stress tolerance. sos6-1 plants are hypersensitive to salt stress and osmotic stress imposed by mannitol or polyethylene glycol in culture media or by water deficit in the soil. SOS6 encodes a cellulose synthase-like protein, AtCSLD5. Only modest differences in cell wall chemical composition could be detected, but we found that sos6-1 mutant plants accumulate high levels of reactive oxygen species (ROS) under osmotic stress and are hypersensitive to the oxidative stress reagent methyl viologen. The results suggest that SOS6/AtCSLD5 is not required for normal plant growth and development but has a critical role in osmotic stress tolerance and this function likely involves its regulation of ROS under stress. © 2010 Blackwell Publishing Ltd.

  11. TNL-mediated immunity in Arabidopsis requires complex regulation of the redundant ADR1 gene family.

    Science.gov (United States)

    Dong, Oliver Xiaoou; Tong, Meixuezi; Bonardi, Vera; El Kasmi, Farid; Woloshen, Virginia; Wünsch, Lisa K; Dangl, Jeffery L; Li, Xin

    2016-05-01

    Nucleotide-binding leucine-rich repeat proteins (NLRs) serve as intracellular immune receptors in animals and plants. Sensor NLRs perceive pathogen-derived effector molecules and trigger robust host defense. Recent studies revealed the role of three coiled-coil-type NLRs (CNLs) of the ADR1 family - ADR1, ADR1-L1 and ADR1-L2 - as redundant helper NLRs, whose function is required for defense mediated by multiple sensor NLRs. From a mutant snc1-enhancing (MUSE) forward genetic screen in Arabidopsis targeted to identify negative regulators of snc1 that encodes a TIR-type NLR (TNL), we isolated two alleles of muse15, both carrying mutations in ADR1-L1. Interestingly, loss of ADR1-L1 also enhances immunity-related phenotypes in other autoimmune mutants including cpr1, bal and lsd1. This immunity-enhancing effect is not mediated by increased SNC1 protein stability, nor is it fully dependent on the accumulation of the defense hormone salicylic acid (SA). Transcriptional analysis revealed an upregulation of ADR1 and ADR1-L2 in the adr1-L1 background, which may overcompensate the loss of ADR1-L1, resulting in enhanced immunity. Interestingly, autoimmunity of snc1 and chs2, which encode typical TNLs, is fully suppressed by the adr1 triple mutant, suggesting that the ADRs are required for TNL downstream signaling. This study extends our knowledge on the interplay among ADRs and reveals their complexity in defense regulation. PMID:27074399

  12. A Protein Complex Required for Polymerase V Transcripts and RNA- Directed DNA Methylation in Arabidopsis

    KAUST Repository

    Law, Julie A.

    2010-05-01

    DNA methylation is an epigenetic modification associated with gene silencing. In Arabidopsis, DNA methylation is established by DOMAINS REARRANGED METHYLTRANSFERASE 2 (DRM2), which is targeted by small interfering RNAs through a pathway termed RNA-directed DNA methylation (RdDM) [1, 2]. Recently, RdDM was shown to require intergenic noncoding (IGN) transcripts that are dependent on the Pol V polymerase. These transcripts are proposed to function as scaffolds for the recruitment of downstream RdDM proteins, including DRM2, to loci that produce both siRNAs and IGN transcripts [3]. However, the mechanism(s) through which Pol V is targeted to specific genomic loci remains largely unknown. Through affinity purification of two known RdDM components, DEFECTIVE IN RNA-DIRECTED DNA METHYLATION 1 (DRD1) [4] and DEFECTIVE IN MERISTEM SILENCING 3 (DMS3) [5, 6], we found that they copurify with each other and with a novel protein, RNA-DIRECTED DNA METHYLATION 1 (RDM1), forming a complex we term DDR. We also found that DRD1 copurified with Pol V subunits and that RDM1, like DRD1 [3] and DMS3 [7], is required for the production of Pol V-dependent transcripts. These results suggest that the DDR complex acts in RdDM at a step upstream of the recruitment or activation of Pol V. © 2010 Elsevier Ltd. All rights reserved.

  13. Arabidopsis thaliana glyoxalase 2-1 is required during abiotic stress but is not essential under normal plant growth.

    Directory of Open Access Journals (Sweden)

    Sriram Devanathan

    Full Text Available The glyoxalase pathway, which consists of the two enzymes, GLYOXALASE 1 (GLX 1 (E.C.: 4.4.1.5 and 2 (E.C.3.1.2.6, has a vital role in chemical detoxification. In Arabidopsis thaliana there are at least four different isoforms of glyoxalase 2, two of which, GLX2-1 and GLX2-4 have not been characterized in detail. Here, the functional role of Arabidopsis thaliana GLX2-1 is investigated. Glx2-1 loss-of-function mutants and plants that constitutively over-express GLX2-1 resemble wild-type plants under normal growth conditions. Insilico analysis of publicly available microarray datasets with ATTEDII, Mapman and Genevestigator indicate potential role(s in stress response and acclimation. Results presented here demonstrate that GLX2-1 gene expression is up-regulated in wild type Arabidopsis thaliana by salt and anoxia stress, and by excess L-Threonine. Additionally, a mutation in GLX2-1 inhibits growth and survival during abiotic stresses. Metabolic profiling studies show alterations in the levels of sugars and amino acids during threonine stress in the plants. Elevated levels of polyamines, which are known stress markers, are also observed. Overall our results suggest that Arabidopsis thaliana GLX2-1 is not essential during normal plant life, but is required during specific stress conditions.

  14. The Kansas Collaborative Research Network, KanCRN: Teaching science content through process

    Science.gov (United States)

    Case, Steven B.

    the technique of Structural Equation Modeling, these factors were combined with participation in the KanCRN research model; this study created and tested a model of science classroom variables related to scores on a science performance assessment. Models were run separately for samples of middle school students (grades 6--8) and high school students (grades 9--12). The middle school model indicates that participation in the KanCRN research model is an independent, positive, direct, and meaningful predictor of science performance. Examination of the magnitude of the standardized coefficients and the R 2 values indicates that 27% of the variance on science achievement is accounted for by the middle school model. The high school model indicated that student attitudes were unrelated to KanCRN participation however, the relationship between participation in KanCRN and students performance on the assessment was not a significant path. Examination of the magnitude of the standardized coefficients and the R2 values for the high school model indicates that 7% of the variance on science achievement is accounted for by the model. This is identical the explanatory power of the high school model that only included information about KanCRN participation and student background characteristics, but leaving out the attitude data. The finding that KanCRN participation is significant at the middle school and is insignificant at the high school raises a number of interesting questions that requires further investigation.

  15. UFO in the Arabidopsis inflorescence apex is required for floral-meristem identity and bract suppression.

    Science.gov (United States)

    Hepworth, Shelley R; Klenz, Jennifer E; Haughn, George W

    2006-03-01

    The UNUSUAL FLORAL ORGANS (UFO) gene of Arabidopsis encodes an F-box protein required for the determination of floral-organ and floral-meristem identity. Mutation of UFO leads to dramatic changes in floral-organ type which are well-characterized whereas inflorescence defects are more subtle and less understood. These defects include an increase in the number of secondary inflorescences, nodes that alternate between forming flowers and secondary inflorescences, and nodes in which a single flower is subtended by a bract. Here, we show how inflorescence defects correlate with the abnormal development of floral primordia and establish a temporal requirement for UFO in this process. At the inflorescence apex of ufo mutants, newly formed primordia are initially bract-like. Expression of the floral-meristem identity genes LFY and AP1 are confined to a relatively small adaxial region of these primordia with expression of the bract-identity marker FIL observed in cells that comprise the balance of the primordia. Proliferation of cells in the adaxial region of these early primordia is delayed by several nodes such that primordia appear "chimeric" at several nodes, having visible floral and bract components. However, by late stage 2 of floral development, growth of the bract generally ceases and is overtaken by development of the floral primordium. This abnormal pattern of floral meristem development is not rescued by expression of UFO from the AP1 promoter, indicating that UFO is required prior to AP1 activation for normal development of floral primordia. We propose that UFO and LFY are jointly required in the inflorescence meristem to both promote floral meristem development and inhibit, in a non-cell autonomous manner, growth of the bract. PMID:16244866

  16. Mitogen-activated protein kinase phosphatase is required for genotoxic stress relief in Arabidopsis

    OpenAIRE

    Ulm, Roman; Revenkova, Ekaterina; Di Sansebastiano, Gian-Pietro; Bechtold, Nicole; Paszkowski, Jerzy

    2001-01-01

    Genotoxic stress activates complex cellular responses allowing for the repair of DNA damage and proper cell recovery. Although plants are exposed constantly to increasing solar UV irradiation, the signaling cascades activated by genotoxic environments are largely unknown. We have identified an Arabidopsis mutant (mkp1) hypersensitive to genotoxic stress treatments (UV-C and methyl methanesulphonate) due to disruption of a gene that encodes an Arabidopsis homolog of mitogen-activated protein k...

  17. Temporal and Spatial Requirement of EMF1 Activity for Arabidopsis Vegetative and Reproductive Development

    Institute of Scientific and Technical Information of China (English)

    Rosario Sánchez; Minjung Y.Kim; Myriam Calonje; Yong-Hwan Moon; Z.Renee Sung

    2009-01-01

    EMBRYONIC FLOWER (EMF) genes are required to maintain vegetative development via repression of flower homeotic genes in Arabidopsis.Removal of EMF gene function caused plants to flower upon germination,producing abnormal and sterile flowers.The pleiotropic effect of emf1 mutation suggests its requirement for gene programs involved in diverse developmental processes.Transgenic plants harboring EMF1 promoter::glucuronidase (GUS) reporter gene were generated to investigate the temporal and spatial expression pattern of EMF1.These plants displayed differential GUS activity in vegetative and flower tissues,consistent with the role of EMF1 in regulating multiple gene programs.EMF1::GUS expression pattern in emf mutants suggests organ-specific auto-regulation.Sense- and antisense (as) EMF1 cDNA were expressed under the control of stage- and tissue-specific promoters in transgenic plants.Characterization of these transgenic plants showed that EMF1 activity is required in meristematic as well as differentiating tissues to rescue emf mutant phenotype.Temporal removal or reduction of EMF1 activity in the embryo or shoot apex of wild-type seedlings was sufficient to cause early flowering and terminal flower formation in adult plants.Such reproductive cell memory is reflected in the flower MADS-box gene activity expressed prior to flowering in these early flowering plants.However,temporal removal of EMF1 activity in flower meristem did not affect flower development.Our results are consistent with EMF1's primary role in repressing flowering in order to allow for vegetative growth.

  18. Spectroscopic characterization of nanocrystalline chromium nitride (CrN).

    Science.gov (United States)

    Mangamma, G; Sairam, T N; Dash, S; Rajalakshmi, M; Kamruddin, M; Mittal, V K; Narasimhan, S V; Arora, A K; Sundar, C S; Tyagi, A K; Raj, Baldev

    2007-03-01

    Nanocrystalline chromiuim nitride has been synthesised by direct gas phase nitridation of nanocrystalline chromia at 1100 degrees C in ammonia-atmosphere. XRD of this material showed formation of single phase CrN with particle size around 20 nm. AFM studies showed particle distribution along with some soft agglomerated nanostructures. Nanocrystalline Cr2O3 and partially-as well as fully--converted nanocrystalline CrN were also investigated using various spectroscopic techniques like XPS, FT-IR, and Raman for gaining insight into the conversion pathways. Spectroscopic investigations of these materials clearly indicate that complete conversion of CrN occurs by nitriding at 1100 degrees C for 4 hrs. The salient spectroscopic features of these nanocrystalline materials with respect to their microcrystalline counterparts are discussed. PMID:17450861

  19. Magnetic properties of epitaxial CrN films

    International Nuclear Information System (INIS)

    The authors have investigated the structural and magnetic properties of CrN films grown on MgO(001) and sapphire(0001) by rf-plasma-assisted molecular beam epitaxy. CrN/MgO(001) exhibits a better epitaxial quality than CrN/sapphire(0001). The CrN/MgO film shows clear paramagnetic behavior at low temperatures, whereas CrN/sapphire exhibits a ferromagneticlike response with an order temperature above room temperature which resembles the magnetic behavior found in Cr-doped dilute magnetic semiconductors. Keeping in mind that bulk CrN exhibits antiferromagnetic behavior, the dramatically different magnetic behaviors found in epitaxial CrN films grown on MgO and sapphire demonstrate the importance of epitaxial constraints in determining their magnetic properties

  20. The CA domain of the respiratory complex I is required for normal embryogenesis in Arabidopsis thaliana.

    Science.gov (United States)

    Córdoba, Juan Pablo; Marchetti, Fernanda; Soto, Débora; Martin, María Victoria; Pagnussat, Gabriela Carolina; Zabaleta, Eduardo

    2016-03-01

    The NADH-ubiquinone oxidoreductase [complex I (CI), EC 1.6.5.3] of the mitochondrial respiratory chain is the principal entry point of electrons, and vital in maintaining metabolism and the redox balance. In a variety of eukaryotic organisms, except animal and fungi (Opisthokonta), it contains an extra domain composed of putative gamma carbonic anhydrases subunits, named the CA domain, which was proposed to be essential for complex I assembly. There are two kinds of carbonic anhydrase subunits: CAs (of which there are three) and carbonic anhydrase-like proteins (CALs) (of which there are two). In plants, the CA domain has been linked to photorespiration. In this work, we report that Arabidopsis mutant plants affected in two specific CA subunits show a lethal phenotype. Double homozygous knockouts ca1ca2 embryos show a significant developmental delay compared to the non-homozygous embryos, which show a wild-type (WT) phenotype in the same silique. Mutant embryos show impaired mitochondrial membrane potential and mitochondrial reactive oxygen species (ROS) accumulation. The characteristic embryo greening does not take place and fewer but larger oil bodies are present. Although seeds look dark brown and wrinkled, they are able to germinate 12 d later than WT seeds. However, they die immediately, most likely due to oxidative stress.Since the CA domain is required for complex I biogenesis, it is predicted that in ca1ca2 mutants no complex I could be formed, triggering the lethal phenotype. The in vivo composition of a functional CA domain is proposed. PMID:26721503

  1. TRIBOLOGICAL PROPERTIES OF CrN COATING UNDER LUBRICATION CONDITIONS

    OpenAIRE

    JANUSZ LUBAS

    2012-01-01

    The paper presents research results of the influence of CrN coating on the friction parameters in friction pairs under lubricated friction conditions. The formed CrN homogeneous coating and CrN-steel 46Cr2 "ring" structure coating was matched under test conditions with a counterpart made from SAE-48 and SAE-783 bearing alloys. Tested sliding pairs were lubricated with 5W/40 Lotos synthetic engine oil. The tribological test was conducted on block-on-ring tester. The applied modification techno...

  2. DELAYED FLOWERING, an Arabidopsis Gene That Acts in the Autonomous Flowering Promotion Pathway and Is Required for Normal Development

    Institute of Scientific and Technical Information of China (English)

    Ming-Jie Chen; Zheng Yuan; Hai Huang

    2006-01-01

    The control of flowering time in higher plants is one of the most important physiological processes and is critical for their reproductive success. To investigate the mechanisms controlling flowering time, we screened for Arabidopsis mutants with late-flowering phenotypes. One mutant, designated delayed flowering (dfr) in the Landsberg erecta (Ler) ecotype, was identified with delayed flowering time. Genetic analysis revealed that dfr is a single gene recessive nuclear mutant and the mutation was mapped to a locus tightly linked to UFO on chromosome 1. To our knowledge, no gene regulating flowering time has been reported yet in this region. The dfr mutant plant showed a delayed flowering time under the different growth conditions examined,including long- and short-day photoperiods and gibberellic acid GA3 treatments, suggesting that DFR is a gene involved in the autonomous flowering promotion pathway. The Arabidopsis gene FLOWERING LOCUS C (FLC) plays a central role in repressing flowering and its transcripts are undetectable in wild-type Ler.However, FLCexpression was upregulated in the dfrmutant, suggesting that DFR is a negative regulator of FLC. In addition, the dfr mutant plant displayed altered valve shapes of the silique and the number of trichomes and branches of each trichome were both reduced, indicating that the DRFgene is also required for normal plant development. Moreover, dfr leafy-5 (Ify-5) double mutant plants showed a much later flowering time than either dfr or Ify-5 single mutants, indicating that DFR and LFYact synergistically to promote flowering in Arabidopsis.

  3. Mitochondrial type-I prohibitins of Arabidopsis thaliana are required for supporting proficient meristem development

    Czech Academy of Sciences Publication Activity Database

    Van Aken, O.; Pečenková, Tamara; van de Cotte, B.; De Rycke, R.; Eeckhout, D.; Fromm, H.; De Jaeger, G.; Witters, E.; Beemster, G.T.S.; Inzé, D.; Van Breusegem, F.

    2007-01-01

    Roč. 52, č. 5 (2007), s. 850-864. ISSN 0960-7412 Institutional research plan: CEZ:AV0Z50380511 Keywords : Arabidopsis * prohibitins * mitochondria Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.751, year: 2007

  4. Peroxidase-dependent apoplastic oxidative burst in Arabidopsis required for pathogen resistance.

    Science.gov (United States)

    Bindschedler, Laurence V; Dewdney, Julia; Blee, Kris A; Stone, Julie M; Asai, Tsuneaki; Plotnikov, Julia; Denoux, Carine; Hayes, Tezni; Gerrish, Chris; Davies, Dewi R; Ausubel, Frederick M; Bolwell, G Paul

    2006-09-01

    The oxidative burst is an early response to pathogen attack leading to the production of reactive oxygen species (ROS) including hydrogen peroxide. Two major mechanisms involving either NADPH oxidases or peroxidases that may exist singly or in combination in different plant species have been proposed for the generation of ROS. We identified an Arabidopsis thaliana azide-sensitive but diphenylene iodonium-insensitive apoplastic oxidative burst that generates H(2)O(2) in response to a Fusarium oxysporum cell-wall preparation. Transgenic Arabidopsis plants expressing an anti-sense cDNA encoding a type III peroxidase, French bean peroxidase type 1 (FBP1) exhibited an impaired oxidative burst and were more susceptible than wild-type plants to both fungal and bacterial pathogens. Transcriptional profiling and RT-PCR analysis showed that the anti-sense (FBP1) transgenic plants had reduced levels of specific peroxidase-encoding mRNAs, including mRNAs corresponding to Arabidopsis genes At3g49120 (AtPCb) and At3g49110 (AtPCa) that encode two class III peroxidases with a high degree of homology to FBP1. These data indicate that peroxidases play a significant role in generating H(2)O(2) during the Arabidopsis defense response and in conferring resistance to a wide range of pathogens. PMID:16889645

  5. Crystal Structure of CRN-4: Implications for Domain Function in Apoptotic DNA Degradation▿

    OpenAIRE

    Hsiao, Yu-Yuan; Nakagawa, Akihisa; Shi, Zhonghao; Mitani, Shohei; Xue, Ding; Yuan, Hanna S.

    2008-01-01

    Cell death related nuclease 4 (CRN-4) is one of the apoptotic nucleases involved in DNA degradation in Caenorhabditis elegans. To understand how CRN-4 is involved in apoptotic DNA fragmentation, we analyzed CRN-4's biochemical properties, in vivo cell functions, and the crystal structures of CRN-4 in apo-form, Mn2+-bound active form, and Er3+-bound inactive form. CRN-4 is a dimeric nuclease with the optimal enzyme activity in cleaving double-stranded DNA in apoptotic salt conditions. Both mut...

  6. The Irish potato famine pathogen Phytophthora infestans translocates the CRN8 kinase into host plant cells

    OpenAIRE

    Damme, van, DA Dick; Bozkurt, T.O.; Cakir, C.; Schornack, S.; Sklenar, J.; Jones, A.M.E.; Kamoun, S

    2012-01-01

    Phytopathogenic oomycetes, such as Phytophthora infestans, secrete an arsenal of effector proteins that modulate plant innate immunity to enable infection. We describe CRN8, a host-translocated effector of P. infestans that has kinase activity in planta. CRN8 is a modular protein of the CRN effector family. The C-terminus of CRN8 localizes to the host nucleus and triggers cell death when the protein is expressed in planta. Cell death induction by CRN8 is dependent on its localization to the p...

  7. Structural properties of CrN buffers for GaN growth

    International Nuclear Information System (INIS)

    We have investigated the structural properties of CrN layers grown on (0001) Al2O3 substrates by molecular-beam epitaxy. The CrN layers of high-crystal quality are obtained at a low growth temperature of 500 .deg. C. X-ray diffraction studies indicate that the CrN layers grow along the direction with a cubic structure. In-situ reflection high-energy electron diffraction investigations clarify that the CrN layers have the following epitaxy relationship with the Al2O3 substrates: of (111) cubic CrN // of (0001) corundum Al2O3 and of (111) cubic CrN // of (0001) corundum Al2O3. Based on the above results, the mismatch of the in-plane lattice spacing between the CrN layers and the Al2O3 substrates is evaluated to be around 6.6 %. When the CrN layers are used as the buffer layers for GaN growth, the GaN layers grown on the CrN layers show well-resolved excitonic emission lines in the photoluminescence spectra, whereas the GaN layers grown without the CrN layers exhibit a broad near-band-edge emission. It is suggested that CrN buffers are effective in relieving the lattice mismatch between Al2O3 substrates and GaN layers.

  8. Improvement of a fully distributed decision making protocol for CRN

    OpenAIRE

    Fernández López, Adrián

    2014-01-01

    Este artículo presenta una propuesta de mejora del protocolo fully distributed decision making protocol for CRN con el fin de llevar a cabo la tarea de detección del espectro libre para las comunicaciones inalámbricas de una manera eficiente y segura.

  9. Cleavage of Model Substrates by Arabidopsis thaliana PRORP1 Reveals New Insights into Its Substrate Requirements.

    Science.gov (United States)

    Mao, Guanzhong; Chen, Tien-Hao; Srivastava, Abhishek S; Kosek, David; Biswas, Pradip K; Gopalan, Venkat; Kirsebom, Leif A

    2016-01-01

    Two broad classes of RNase P trim the 5' leader of precursor tRNAs (pre-tRNAs): ribonucleoprotein (RNP)- and proteinaceous (PRORP)-variants. These two RNase P types, which use different scaffolds for catalysis, reflect independent evolutionary paths. While the catalytic RNA-based RNP form is present in all three domains of life, the PRORP family is restricted to eukaryotes. To obtain insights on substrate recognition by PRORPs, we examined the 5' processing ability of recombinant Arabidopsis thaliana PRORP1 (AtPRORP1) using a panel of pre-tRNASer variants and model hairpin-loop derivatives (pATSer type) that consist of the acceptor-T-stem stack and the T-/D-loop. Our data indicate the importance of the identity of N-1 (the residue immediately 5' to the cleavage site) and the N-1:N+73 base pair for cleavage rate and site selection of pre-tRNASer and pATSer. The nucleobase preferences that we observed mirror the frequency of occurrence in the complete suite of organellar pre-tRNAs in eight algae/plants that we analyzed. The importance of the T-/D-loop in pre-tRNASer for tight binding to AtPRORP1 is indicated by the 200-fold weaker binding of pATSer compared to pre-tRNASer, while the essentiality of the T-loop for cleavage is reflected by the near-complete loss of activity when a GAAA-tetraloop replaced the T-loop in pATSer. Substituting the 2'-OH at N-1 with 2'-H also resulted in no detectable cleavage, hinting at the possible role of this 2'-OH in coordinating Mg2+ ions critical for catalysis. Collectively, our results indicate similarities but also key differences in substrate recognition by the bacterial RNase P RNP and AtPRORP1: while both forms exploit the acceptor-T-stem stack and the elbow region in the pre-tRNA, the RNP form appears to require more recognition determinants for cleavage-site selection. PMID:27494328

  10. Cleavage of Model Substrates by Arabidopsis thaliana PRORP1 Reveals New Insights into Its Substrate Requirements

    Science.gov (United States)

    Srivastava, Abhishek S.; Kosek, David; Biswas, Pradip K.; Gopalan, Venkat; Kirsebom, Leif A.

    2016-01-01

    Two broad classes of RNase P trim the 5' leader of precursor tRNAs (pre-tRNAs): ribonucleoprotein (RNP)- and proteinaceous (PRORP)-variants. These two RNase P types, which use different scaffolds for catalysis, reflect independent evolutionary paths. While the catalytic RNA-based RNP form is present in all three domains of life, the PRORP family is restricted to eukaryotes. To obtain insights on substrate recognition by PRORPs, we examined the 5' processing ability of recombinant Arabidopsis thaliana PRORP1 (AtPRORP1) using a panel of pre-tRNASer variants and model hairpin-loop derivatives (pATSer type) that consist of the acceptor-T-stem stack and the T-/D-loop. Our data indicate the importance of the identity of N-1 (the residue immediately 5' to the cleavage site) and the N-1:N+73 base pair for cleavage rate and site selection of pre-tRNASer and pATSer. The nucleobase preferences that we observed mirror the frequency of occurrence in the complete suite of organellar pre-tRNAs in eight algae/plants that we analyzed. The importance of the T-/D-loop in pre-tRNASer for tight binding to AtPRORP1 is indicated by the 200-fold weaker binding of pATSer compared to pre-tRNASer, while the essentiality of the T-loop for cleavage is reflected by the near-complete loss of activity when a GAAA-tetraloop replaced the T-loop in pATSer. Substituting the 2'-OH at N-1 with 2'-H also resulted in no detectable cleavage, hinting at the possible role of this 2'-OH in coordinating Mg2+ ions critical for catalysis. Collectively, our results indicate similarities but also key differences in substrate recognition by the bacterial RNase P RNP and AtPRORP1: while both forms exploit the acceptor-T-stem stack and the elbow region in the pre-tRNA, the RNP form appears to require more recognition determinants for cleavage-site selection. PMID:27494328

  11. An Arabidopsis flavonoid transporter is required for anther dehiscence and pollen development

    OpenAIRE

    Thompson, Elinor P.; Wilkins, Christopher; Demidchik, Vadim; Davies, Julia M; Glover, Beverley J.

    2010-01-01

    FLOWER FLAVONOID TRANSPORTER (FFT) encodes a multidrug and toxin efflux family transporter in Arabidopsis thaliana. FFT (AtDTX35) is highly transcribed in floral tissues, the transcript being localized to epidermal guard cells, including those of the anthers, stigma, siliques and nectaries. Mutant analysis demonstrates that the absence of FFT transcript affects flavonoid levels in the plant and that the altered flavonoid metabolism has wide-ranging consequences. Root growth, seed development ...

  12. The Arabidopsis Golgi-localized GDP-L-fucose transporter is required for plant development

    OpenAIRE

    Rautengarten, Carsten; Ebert, Berit; Liu, Lifeng; Stonebloom, Solomon; Smith-Moritz, Andreia M.; Pauly, Markus; Orellana, Ariel; Scheller, Henrik Vibe; Heazlewood, Joshua L.

    2016-01-01

    Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1 (GFT1), an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rh...

  13. The Recovery of Plastid Function Is Required for Optimal Response to Low Temperatures in Arabidopsis

    OpenAIRE

    Kindgren, Peter; Dubreuil, Carole; Strand, Åsa

    2015-01-01

    Cold acclimation is an essential response in higher plants to survive freezing temperatures. Here, we report that two independent mutant alleles of the H-subunit of Mg-chelatase, CHLH, gun5-1 and cch in Arabidopsis are sensitive to low temperatures. Plants were grown in photoperiodic conditions and exposed to low temperatures for short-and long-term periods. Tetrapyrrole biosynthesis was initially significantly inhibited in response to low temperature but recovered in wild type (Col-0), altho...

  14. Requirement of KNAT1/BP for the Development of Abscission Zones in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qun Wang; Wei-Hui Xu; Li-Geng Ma; Zhi-Ming Fu; Xing-Wang Deng; Jia-Yang Li; Yong-Hong Wang

    2006-01-01

    The KNAT1 gene is a member of the Class Ⅰ KNOXhomeobox gene family and is thought to play an important role in meristem development and leaf morphogenesis. Recent studies have demonstrated that KNAT1/BP regulates the architecture of the inflorescence by affecting pedicle development in Arabidopsis thaliana.Herein, we report the characterization of an Arabidopsis T-DNA insertion mutant that shares considerable phenotypic similarity to the previously identified mutant brevipedicle (bp). Molecular and genetic analyses showed that the mutant is allelic to bp and that the T-DNA is located within the first helix of the KNAT1homeodomain (HD). Although the mutation causes a typical abnormality of short pedicles, propendent siliques,and semidwarfism, no obvious defects are observed in the vegetative stage. A study on cell morphology showed that asymmetrical division and inhibition of cell elongation contribute to the downward-pointing and shorter pedicle phenotype. Loss of KNAT/BPfunction results in the abnormal development of abscission zones. Microarray analysis of gene expression profiling suggests that KNAT1/BP may regulate abscission zone development through hormone signaling and hormone metabolism in Arabidopsis.

  15. Evolutionarily distant pathogens require the Arabidopsis phytosulfokine signalling pathway to establish disease.

    Science.gov (United States)

    Rodiuc, Natalia; Barlet, Xavier; Hok, Sophie; Perfus-Barbeoch, Laetitia; Allasia, Valérie; Engler, Gilbert; Séassau, Aurélie; Marteu, Nathalie; de Almeida-Engler, Janice; Panabières, Franck; Abad, Pierre; Kemmerling, Birgit; Marco, Yves; Favery, Bruno; Keller, Harald

    2016-07-01

    Secreted peptides and their specific receptors frequently orchestrate cell-to-cell communication in plants. Phytosulfokines (PSKs) are secreted tyrosine-sulphated peptide hormones, which trigger cellular dedifferentiation and redifferentiation upon binding to their membrane receptor. Biotrophic plant pathogens frequently trigger the differentiation of host cells into specialized feeding structures, which are essential for successful infection. We found that oomycete and nematode infections were characterized by the tissue-specific transcriptional regulation of genes encoding Arabidopsis PSKs and the PSK receptor 1 (PSKR1). Subcellular analysis of PSKR1 distribution showed that the plasma membrane-bound receptor internalizes after binding of PSK-α. Arabidopsis pskr1 knockout mutants were impaired in their susceptibility to downy mildew infection. Impaired disease susceptibility depends on functional salicylic acid (SA) signalling, but not on the massive up-regulation of SA-associated defence-related genes. Knockout pskr1 mutants also displayed a major impairment of root-knot nematode reproduction. In the absence of functional PSKR1, giant cells arrested their development and failed to fully differentiate. Our findings indicate that the observed restriction of PSK signalling to cells surrounding giant cells contributes to the isotropic growth and maturation of nematode feeding sites. Taken together, our data suggest that PSK signalling in Arabidopsis promotes the differentiation of host cells into specialized feeding cells. PMID:26290138

  16. Electrochemical characteristics of CrN thin films prepared by ion-beam-enhanced deposition

    International Nuclear Information System (INIS)

    It has been known that CrN has high hardness and high resistance against wear, oxidation and corrosion. Although many studies have been done on its mechanical and high temperature oxidation properties, studies on its electrochemical and corrosion properties in aqueous solutions are still limited. The aim of this study is to produce CrN thin films by ion-beam-enhanced deposition (IBED) and to make clear the corrosion behavior of CrN by electrochemical measurements. CrN thin films were prepared by IBED under various conditions and their polarization curves were measured in 1 kmol·m-3 H2SO4 and 12 kmol·m-3 HCl. Changes in the surface of the thin films by polarization were examined by XPS and in-situ ellipsometry. The thin films prepared by IBED were composed of the large amount of CrN and small amounts of Cr2N and Cr. The fraction of CrN in the films increased with increasing flow rate of nitrogen. Potentiodynamic polarization curves exhibited that the active dissolution rate of the films decreased with increasing CrN content of the films. The films with high CrN content showed excellent corrosion resistance up to the start potential of transpassive dissolution without formation of passive films. That is, the excellent corrosion resistance of CrN results from the intrinsic inactive nature of CrN surface. (author)

  17. Localization of Iron in Arabidopsis Seed Requires the Vacuolar Membrane Transporter VIT1

    International Nuclear Information System (INIS)

    Iron deficiency is a major human nutritional problem wherever plant-based diets are common. Using synchrotron x-ray fluorescence microtomography to directly visualize iron in Arabidopsis seeds, we show that iron is localized primarily to the provascular strands of the embryo. This localization is completely abolished when the vacuolar iron uptake transporter VIT1 is disrupted. Vacuolar iron storage is also critical for seedling development because vit1-1 seedlings grow poorly when iron is limiting. We have uncovered a fundamental aspect of seed biology that will ultimately aid the development of nutrient-rich seed, benefiting both human health and agricultural productivity

  18. Cloning and characterization of a gene (UVR3) required for photorepair of 6-4 photoproducts in Arabidopsis thaliana

    International Nuclear Information System (INIS)

    UV radiation induces two major classes of pyrimidine dimers: the pyrimidine [6-4] pyrimidone photoproduct (6-4 product) and the cyclobutane pyrimidine dimer (CPD). Many organisms produce enzymes, termed photolyases, that specifically bind to these damage products and split them via a UV-A/blue light-dependent mechanism, thereby reversing the damage. These photolyases are specific for either CPDs or 6-4 products. A gene that expresses a protein with 6-4 photolyase activity in vitro was recently cloned from Drosophila melanogaster and Xenopus laevis. We report here the isolation of a homolog of this gene, cloned on the basis of sequence similarity, from the higher plant Arabidopsis thaliana. This cloned gene produces a protein with 6-4 photolyase activity when expressed in Escherichia coli. We also find that a previously described mutant of Arabidopsis (uvr3) that is defective in photoreactivation of 6-4 products carries a nonsense mutation in this 6-4 photolyase homolog. We have therefore termed this gene UVR3. Although homologs of this gene have previously been shown to produce a functional 6-4 photolyase when expressed in heterologous systems, this is the first demonstration of a requirement for this gene for photoreactivation of 6-4 products in vivo

  19. Arabidopsis MSI1 Is Required for Negative Regulation of the Response to Drought Stress

    Institute of Scientific and Technical Information of China (English)

    Cristina Alexandre; Yvonne M(o)ller-Steinbach; Nicole Sch(o)nrock; Wilhelm Gruissem; Lars Hennig

    2009-01-01

    Arabidopsis MSI1 has fundamental functions in plant development.MSI1 is a subunit of Polycomb group protein complexes and Chromatin assembly factor 1,and it interacts with the Retinoblastoma-related protein 1.Altered levels of MSI1 result in pleiotropic phenotypes,reflecting the complexity of MSI1 protein functions.In order to uncover additional functions of MSI1,we performed transcriptional profiling of wild-type and plants with highly reduced MSI1 levels (msil-cs).Surprisingly,the known functions of MSI1 could only account for a minor part of the transcriptional changes in msi1-cs plants.One of the most striking unexpected observations was the up-regulation of a subset of ABA-responsive genes eliciting the response to drought and salt stress.We report that MSI1 can bind to the chromatin of the drought-inducible downstream target RD20 and suggest a new role for MSI1 in the negative regulation of the Arabidopsis drought-stress response.

  20. Competition between Magnetic and Structural Transition in CrN

    OpenAIRE

    Filippetti, A.; Pickett, W. E.; Klein, B. M.

    1998-01-01

    CrN is observed to undergo a paramagnetic to antiferromagnetic transition accompanied by a shear distortion from cubic NaCl-type to orthorhombic structure. Our first-principle plane wave and ultrasoft pseudopotential calculations confirm that the distorted antiferromagnetic phase with spin configuration arranged in double ferromagnetic sheets along [110] is the most stable. Antiferromagnetic ordering leads to a large depletion of states around Fermi level, but it does not open a gap. Simultan...

  1. Investigation of preparation technique and tribological properties of CrN piston rings coatings

    International Nuclear Information System (INIS)

    By using multi-ion plating, CrN films were made on surface of piston rings to improve its tribological properties and service life. Effects of nitrogen content to prepare the film on hardness and phase structure were studied. The high-temperature tribological properties of Cr plating and CrN films were compared with CETR friction tester. The results show that nitrogen partial pressure significantly affects the mechanical properties of CrN films. With increasing N2 partial pressure, preferential growth orientation of the film changed from Cr2N(211) to CrN(220) phase, leading to two hardness peaks corresponding to the Cr2N and CrN phases,respectively. Having higher high-temperature wear resistance and lower friction coefficient than Cr plating, the CrN films are suitable for piston rings under high temperature conditions. (authors)

  2. Functional characterization of human CRN2 (coronin-1C) in normal and disease conditions

    OpenAIRE

    Xavier, Charles-Peter

    2009-01-01

    Coronins are in general versatile actin filament-crosslinking and bundling proteins. In human, seven subfamilies of coronins are identified. One of these proteins found ubiquitously expressed in human tissues is CRN2 (synonyms: coronin-1C, coronin-3). Here, we study in vivo and in vitro F-actin associated properties of CRN2. Using different GFP tagged structural domain proteins and RNAi mediated knock down of CRN2, we studied the role of these domains in various cellular activities like wound...

  3. Arabidopsis VARIEGATED 3 encodes a chloroplasttargeted, zinc-finger protein required for chloroplast and palisade cell development

    DEFF Research Database (Denmark)

    Næsted, Henrik; Holm, A.; Jenkins, T.; Nielsen, H.B.; Harris, C.A.; Beale, M.H.; Andersen, M.; Mant, A.; Scheller, H.; Camara, B.; Mattsson, O.; Mundy, J.

    2004-01-01

    The stable, recessive Arabidopsis variegated 3 (var3) mutant exhibits a variegated phenotype due to somatic areas lacking or containing developmentally retarded chloroplasts and greatly reduced numbers of palisade cells. The VAR3 gene, isolated by transposon tagging, encodes the 85.9 kDa VAR3 pro...... pigment profiles are qualitatively similar in wild type and var3, although var3 accumulates lower levels of chlorophylls and carotenoids. These results indicate that VAR3 is a part of a protein complex required for normal chloroplast and palisade cell development....... protein containing novel repeats and zinc fingers described as protein interaction domains. VAR3 interacts specifically in yeast and in vitro with NCED4, a putative polyene chain or carotenoid dioxygenase, and both VAR3 and NCED4 accumulate in the chloroplast stroma. Metabolic profiling demonstrates that...

  4. Repression of AS2 by WOX family transcription factors is required for leaf development in Medicago and Arabidopsis.

    Science.gov (United States)

    Zhang, Fei; Tadege, Million

    2015-01-01

    WOX transcription factors are key regulators of meristematic activity in plants. The Medicago WOX gene, STF, functions in maintenance of leaf marginal meristem, analogous to the function of WUS in the shoot apical meristem. Both STF and WUS directly repress AS2 expression in their respective domains. Ectopic expression of AS2 with WUS promoter leads to a narrow leaf phenotype and other phenotypes similar to the wus mutant. We also found that a wox1 prs wus triple mutant produces much narrower leaf blades than the wox1 prs double mutant, indicating that WUS genetically interacts with WOX1 and PRS in Arabidopsis leaf blade development. Our data points to a general requirement for AS2 repression in meristematic regions to allow cell proliferation. PMID:25807065

  5. Rhizobacteria-mediated induced systemic resistance (ISR) in Arabidopsis requires sensitivity to jasmonate and ethylene but is not accompanied by an increase in their production

    NARCIS (Netherlands)

    Pieterse, C.M.J.; Pelt, J.A. van; Ton, J.; Parchmann, S.; Mueller, M.J.; Buchala, A.J.; Métraux, J.P.; Loon, L.C. van

    2000-01-01

    Plants develop an enhanced defensive capacity against a broad spectrum of plant pathogens after colonization of the roots by selected strains of nonpathogenic biocontrol bacteria. In Arabidopsis thaliana, this induced systemic resistance (ISR) functions independently of salicylic acid but requires a

  6. PROTEIN TARGETING TO STARCH is required for localising GRANULE-BOUND STARCH SYNTHASE to starch granules and for normal amylose synthesis in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    David Seung

    2015-02-01

    Full Text Available The domestication of starch crops underpinned the development of human civilisation, yet we still do not fully understand how plants make starch. Starch is composed of glucose polymers that are branched (amylopectin or linear (amylose. The amount of amylose strongly influences the physico-chemical behaviour of starchy foods during cooking and of starch mixtures in non-food manufacturing processes. The GRANULE-BOUND STARCH SYNTHASE (GBSS is the glucosyltransferase specifically responsible for elongating amylose polymers and was the only protein known to be required for its biosynthesis. Here, we demonstrate that PROTEIN TARGETING TO STARCH (PTST is also specifically required for amylose synthesis in Arabidopsis. PTST is a plastidial protein possessing an N-terminal coiled coil domain and a C-terminal carbohydrate binding module (CBM. We discovered that Arabidopsis ptst mutants synthesise amylose-free starch and are phenotypically similar to mutants lacking GBSS. Analysis of granule-bound proteins showed a dramatic reduction of GBSS protein in ptst mutant starch granules. Pull-down assays with recombinant proteins in vitro, as well as immunoprecipitation assays in planta, revealed that GBSS physically interacts with PTST via a coiled coil. Furthermore, we show that the CBM domain of PTST, which mediates its interaction with starch granules, is also required for correct GBSS localisation. Fluorescently tagged Arabidopsis GBSS, expressed either in tobacco or Arabidopsis leaves, required the presence of Arabidopsis PTST to localise to starch granules. Mutation of the CBM of PTST caused GBSS to remain in the plastid stroma. PTST fulfils a previously unknown function in targeting GBSS to starch. This sheds new light on the importance of targeting biosynthetic enzymes to sub-cellular sites where their action is required. Importantly, PTST represents a promising new gene target for the biotechnological modification of starch composition, as it is

  7. Male Sterile2 Encodes a Plastid-Localized Fatty Acyl Carrier Protein Reductase Required for Pollen Exine Development in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.; Shanklin, J.; Yu, X.-H.; Zhang, K.; Shi, J.; De Oliveira, S.; Schreiber, L.; Zhang, D.

    2011-10-01

    Male Sterile2 (MS2) is predicted to encode a fatty acid reductase required for pollen wall development in Arabidopsis (Arabidopsis thaliana). Transient expression of MS2 in tobacco (Nicotiana benthamiana) leaves resulted in the accumulation of significant levels of C16 and C18 fatty alcohols. Expression of MS2 fused with green fluorescent protein revealed that an amino-terminal transit peptide targets the MS2 to plastids. The plastidial localization of MS2 is biologically important because genetic complementation of MS2 in ms2 homozygous plants was dependent on the presence of its amino-terminal transit peptide or that of the Rubisco small subunit protein amino-terminal transit peptide. In addition, two domains, NAD(P)H-binding domain and sterile domain, conserved in MS2 and its homologs were also shown to be essential for MS2 function in pollen exine development by genetic complementation testing. Direct biochemical analysis revealed that purified recombinant MS2 enzyme is able to convert palmitoyl-Acyl Carrier Protein to the corresponding C16:0 alcohol with NAD(P)H as the preferred electron donor. Using optimized reaction conditions (i.e. at pH 6.0 and 30 C), MS2 exhibits a K{sub m} for 16:0-Acyl Carrier Protein of 23.3 {+-} 4.0 {mu}m, a V{sub max} of 38.3 {+-} 4.5 nmol mg{sup -1} min{sup -1}, and a catalytic efficiency/K{sub m} of 1,873 m{sup -1} s{sup -1}. Based on the high homology of MS2 to other characterized fatty acid reductases, it was surprising that MS2 showed no activity against palmitoyl- or other acyl-coenzyme A; however, this is consistent with its plastidial localization. In summary, genetic and biochemical evidence demonstrate an MS2-mediated conserved plastidial pathway for the production of fatty alcohols that are essential for pollen wall biosynthesis in Arabidopsis.

  8. A novel chloroplast-localized protein EMB1303 is required for chloroplast development in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Xiaozhen Huang; Xiaoyan Zhang; Shuhua Yang

    2009-01-01

    To understand the molecular mechanisms underlying chloroplast development, we isolated and characterized the albino mutant emb1303-1 in Arabidopsis. The mutant displayed a severe dwarf phenotype with small albino rosette leaves and short roots on a synthetic medium containing sucrose. It is pigment-deficient and seedling lethal when grown in soil. Embryo development was delayed in the mutant, although seed germination was not significantly im-paired. The plastids of emb1303-1 were arrested in early developmental stages without the classical stack of thylakoid membrane. Genetic and molecular analyses uncovered that the EMB1303 gene encodes a novel chloroplast-localized protein. Mieroarray and RT-PCR analyses revealed that a number of nuclear-and plastid-encoded genes involved in photosynthesis and chloroplast biogenesis were substantially downregulated in the mutant. Moreover, the accu-mulation of several major chloroplast proteins was severely compromised in emb1303-1. These results suggest that EMBI303 is essential for chloroplast development.

  9. Arabidopsis R-SNARE proteins VAMP721 and VAMP722 are required for cell plate formation.

    Directory of Open Access Journals (Sweden)

    Liang Zhang

    Full Text Available BACKGROUND: Cell plate formation during plant cytokinesis is facilitated by SNARE complex-mediated vesicle fusion at the cell-division plane. However, our knowledge regarding R-SNARE components of membrane fusion machinery for cell plate formation remains quite limited. METHODOLOGY/PRINCIPAL FINDINGS: We report the in vivo function of Arabidopsis VAMP721 and VAMP722, two closely sequence-related R-SNAREs, in cell plate formation. Double homozygous vamp721vamp722 mutant seedlings showed lethal dwarf phenotypes and were characterized by rudimentary roots, cotyledons and hypocotyls. Furthermore, cell wall stubs and incomplete cytokinesis were frequently observed in vamp721vamp722 seedlings. Confocal images revealed that green fluorescent protein-tagged VAMP721 and VAMP722 were preferentially localized to the expanding cell plates in dividing cells. Drug treatments and co-localization analyses demonstrated that punctuate organelles labeled with VAMP721 and VAMP722 represented early endosomes overlapped with VHA-a1-labeled TGN, which were distinct from Golgi stacks and prevacuolar compartments. In addition, protein traffic to the plasma membrane, but not to the vacuole, was severely disrupted in vamp721vamp722 seedlings by subcellular localization of marker proteins. CONCLUSION/SIGNIFICANCE: These observations suggest that VAMP721 and VAMP722 are involved in secretory trafficking to the plasma membrane via TGN/early endosomal compartment, which contributes substantially to cell plate formation during plant cytokinesis.

  10. MYB103 is required for FERULATE-5-HYDROXYLASE expression and syringyl lignin biosynthesis in Arabidopsis stems.

    Science.gov (United States)

    Öhman, David; Demedts, Brecht; Kumar, Manoj; Gerber, Lorenz; Gorzsás, András; Goeminne, Geert; Hedenström, Mattias; Ellis, Brian; Boerjan, Wout; Sundberg, Björn

    2013-01-01

    The transcription factor MYB103 was previously identified as a member of the transcriptional network regulating secondary wall biosynthesis in xylem tissues of Arabidopsis, and was proposed to act on cellulose biosynthesis. It is a direct transcriptional target of the transcription factor SECONDARY WALL ASSOCIATED NAC DOMAIN PROTEIN 1 (SND1), and 35S-driven dominant repression or over-expression of MYB103 modifies secondary wall thickness. We identified two myb103 T-DNA insertion mutants and chemically characterized their lignocellulose by pyrolysis/GC/MS, 2D NMR, FT-IR microspectroscopy and wet chemistry. The mutants developed normally but exhibited a 70-75% decrease in syringyl (S) lignin. The level of guaiacyl (G) lignin was co-ordinately increased, so that total Klason lignin was not affected. The transcript abundance of FERULATE-5-HYDROXYLASE (F5H), the key gene in biosynthesis of S lignin, was strongly decreased in the myb103 mutants, and the metabolomes of the myb103 mutant and an F5H null mutant were very similar. Other than modification of the lignin S to G ratio, there were only very minor changes in the composition of secondary cell-wall polymers in the inflorescence stem. In conclusion, we demonstrate that F5H expression and hence biosynthesis of S lignin are dependent on MYB103. PMID:22967312

  11. Gibberellic acid signaling is required for ambient temperature-mediated induction of flowering in Arabidopsis thaliana.

    Science.gov (United States)

    Galvão, Vinicius Costa; Collani, Silvio; Horrer, Daniel; Schmid, Markus

    2015-12-01

    Distinct molecular mechanisms integrate changes in ambient temperature into the genetic pathways that govern flowering time in Arabidopsis thaliana. Temperature-dependent eviction of the histone variant H2A.Z from nucleosomes has been suggested to facilitate the expression of FT by PIF4 at elevated ambient temperatures. Here we show that, in addition to PIF4, PIF3 and PIF5, but not PIF1 and PIF6, can promote flowering when expressed specifically in phloem companion cells (PCC), where they can induce FT and its close paralog, TSF. However, despite their strong potential to promote flowering, genetic analyses suggest that the PIF genes seem to have only a minor role in adjusting flowering in response to photoperiod or high ambient temperature. In addition, loss of PIF function only partially suppressed the early flowering phenotype and FT expression of the arp6 mutant, which is defective in H2A.Z deposition. In contrast, the chemical inhibition of gibberellic acid (GA) biosynthesis resulted in a strong attenuation of early flowering and FT expression in arp6. Furthermore, GA was able to induce flowering at low temperature (15°C) independently of FT, TSF, and the PIF genes, probably directly at the shoot apical meristem. Together, our results suggest that the timing of the floral transition in response to ambient temperature is more complex than previously thought and that GA signaling might play a crucial role in this process. PMID:26466761

  12. Endogenous salicylic acid is required for promoting cadmium tolerance of Arabidopsis by modulating glutathione metabolisms.

    Science.gov (United States)

    Guo, Bin; Liu, Chen; Li, Hua; Yi, Keke; Ding, Nengfei; Li, Ningyu; Lin, Yicheng; Fu, Qinglin

    2016-10-01

    A few studies with NahG transgenic lines of Arabidopsis show that depletion of SA enhances cadmium (Cd) tolerance. However, it remains some uncertainties that the defence signaling may be a result of catechol accumulation in NahG transgenic lines but not SA deficiency. Here, we conducted a set of hydroponic assays with another SA-deficient mutant sid2 to examine the endogenous roles of SA in Cd tolerance, especially focusing on the glutathione (GSH) cycling. Our results showed that reduced SA resulted in negative effects on Cd tolerance, including decreased Fe uptake and chlorophyll concentration, aggravation of oxidative damage and growth inhibition. Cd exposure significantly increased SA concentration in wild-type leaves, but did not affect it in sid2 mutants. Depletion of SA did not disturb the Cd uptake in either roots or shoots. The reduced Cd tolerance in sid2 mutants is due to the lowered GSH status, which is associated with the decreased expression of serine acetyltransferase along with a decline in contents of non-protein thiols, phytochelatins, and the lowered transcription and activities of glutathione reductase1 (GR1) which reduced GSH regeneration. Finally, the possible mode of SA signaling through the GR/GSH pathway during Cd exposure is discussed. PMID:27209521

  13. Surface morphological evolution of epitaxial CrN(001) layers

    International Nuclear Information System (INIS)

    CrN layers, 57 and 230 nm thick, were grown on MgO(001) at Ts=600-800 deg. C by ultrahigh-vacuum magnetron sputter deposition in pure N2 discharges from an oblique deposition angle α=80 deg. . Layers grown at 600 deg. C nucleate as single crystals with a cube-on-cube epitaxial relationship with the substrate. However, rough surfaces with cauliflower-type morphologies cause the nucleation of misoriented CrN grains that develop into cone-shaped grains that protrude out of the epitaxial matrix to form triangular faceted surface mounds. The surface morphology of epitaxial CrN(001) grown at 700 deg. C is characterized by dendritic ridge patterns extending along the orthogonal directions superposed by square-shaped super mounds with edges. The ridge patterns are attributed to a Bales-Zangwill instability while the supermounds form due to atomic shadowing which leads to the formation of epitaxial inverted pyramids that are separated from the surrounding layer by tilted nanovoids. Growth at 800 deg. C yields complete single crystals with smooth surfaces. The root-mean-square surface roughness for 230-nm-thick layers decreases from 18.8 to 9.3 to 1.1 nm as Ts is raised from 600 to 700 to 800 deg. C. This steep decrease is due to a transition in the roughening mechanism from atomic shadowing to kinetic roughening. Atomic shadowing is dominant at 600 and 700 deg. C, where misoriented grains and supermounds, respectively, capture a larger fraction of the oblique deposition flux in comparison to the surrounding epitaxial matrix, resulting in a high roughening rate that is described by a power law with an exponent β>0.5. In contrast, kinetic roughening controls the surface morphology for Ts=800 deg. C, as well as the epitaxial fraction of the layers grown at 600 and 700 deg. C, yielding relatively smooth surfaces and β≤0.27

  14. Cloning, overexpression, purification and crystallization of the CRN12 coiled-coil domain from Leishmania donovani

    OpenAIRE

    Srivastava, Vijay Kumar; Rana, Ajay Kumar; Sahasrabuddhe, Amogh A.; Gupta, C M; Pratap, J.V.

    2013-01-01

    The L. donovani coronin CRN12 coiled-coil domain (5.8 kDa) was cloned, overexpressed and purified to homogeneity. Crystals of recombinant L. donovani coronin CRN12 coiled-coil domain were grown by vapour diffusion using a hanging-drop setup.

  15. Elaboration, characterization of CrN- based coatings

    International Nuclear Information System (INIS)

    Cr, CrN and CrAlN monolayers were synthesized by RF dual magnetron sputtering on AISI4140 steel and silicon substrates at 200 deg. C. Multilayers coatings based on the three mono-layers such as CrN/CrAlN and Cr/CrN/CrAlN were also synthesized only on Si. The physico-chemical and mechanical properties of the layers were determined by AFM, SEM+WDS, stress, roughness and nanoindentation measurements. The influence of the thickness on the mechanical properties of the monolayers stresses has been studied and as a consequence we compared the mono and multilayers stress state.

  16. Elaboration, characterization of Cr-N based coatings

    OpenAIRE

    Tlili, Brahim; Nouveau, Corinne; Guillemot, Gildas

    2010-01-01

    Cr, CrN and CrAlN monolayers were synthesized by RF dual magnetron sputtering on AISI4140 steel and silicon substrates at 200°C. Multilayers coatings based on the three mono-layers such as CrN/CrAlN and Cr/CrN/CrAlN were also synthesized only on Si. The physico-chemical and mechanical properties of the layers were determined by AFM, SEM+WDS, stress, roughness and nanoindentation measurements. The influence of the thickness on the mechanical properties of the monolayers stresses has been st...

  17. HYL1 is required for establishment of stamen architecture with four microsporangia in Arabidopsis.

    Science.gov (United States)

    Lian, Heng; Li, Xiaorong; Liu, Zhongyuan; He, Yuke

    2013-08-01

    The stamen produces pollen grains for pollination in higher plants. Coordinated development of four microsporangia in the stamen is essential for normal fertility. The roles of miR165/166-directed pathways in the establishment of adaxial-abaxial polarity have been well defined in leaves. However, the molecular mechanism underlying the adaxial-abaxial polarity of the stamen is elusive. Here it is reported that HYPONASTIC LEAVES1 (HYL1), a general regulator of microRNA (miRNA) biogenesis, plays an essential role in establishing the stamen architecture of the four microsporangia in Arabidopsis thaliana. In stamens, HYL1 and miR165/6 expression are progressively restricted to the lateral region, microsporangia, microspore mother cells, and microspores, whereas HD-ZIP III genes are preferentially expressed in the middle region, vascular bundle, and stomium. Loss of HYL1 leads to the formation of two rather than four microsporangia in each stamen. In the stamen of the hyl1 mutant, miR165/6 accumulation is reduced, whereas miR165/6-targeted HD-ZIP III genes are up-regulated and FILAMENTOUS FLOWER (FIL) is down-regulated; and, specifically, REVOLUTA (REV) is overexpressed in the adaxial region and FIL is underexpressed in the abaxial regions, concomitant with the aberrance of the two inner microsporangia and partial adaxialization of the connectives. Genetic analysis reveals that FIL works downstream of HYL1, and the defects in hyl1 stamens are partially rescued by rev-9 or phv-5 phb-6 alleles. These results suggest that HYL1 modulates inner microsporangia and stamen architecture by repression of HD-ZIP III genes and promotion of the FIL gene through miR165/6. Thus, the role of HYL1 in establishment of stamen architecture provides insight into the molecular mechanism of male fertility. PMID:23918970

  18. Computational simulation of the CrN - FCC structure; Simulación computacional de la estructura FCC del CrN

    OpenAIRE

    ALEXANDER RUDEN MUÑOZ; JUAN MANUEL GONZALEZ CARMONA; ELISABET RESTREPO PARRA

    2013-01-01

    CrN thin films were synthesized via Magnetron Sputtering deposition technique on (111) oriented Silicon substrates. Coatings were analyzed by using X-ray Diffraction (XRD) and Raman spectroscopy, determining the cubic phase for the ceramic compound. Computational simulation of the CrN cubic crystallographic structure, performed by using Density Functional Theory (DFT), showed stability by the sum of Mulliquen charges equal to zero and compound hybridization with characteristic sp molecular or...

  19. Surface free energy of CrN x films deposited using closed field unbalanced magnetron sputtering

    International Nuclear Information System (INIS)

    CrN x thin films have attracted much attention for semiconductor IC packaging molding dies and forming tools due to their excellent hardness, thermal stability and non-sticking properties (low surface free energy). However, few data has been published on the surface free energy (SFE) of CrN x films at temperatures in the range 20-170 deg. C. In this study CrN x thin films with CrN, Cr(N), Cr2N (and mixture of these phases) were prepared using closed field unbalanced magnetron sputtering at a wide range of Cr+2 emission intensity. The contact angles of water, di-iodomethane and ethylene glycol on the coated surfaces were measured at temperatures in the range 20-170 deg. C using a Dataphysics OCA-20 contact angle analyzer. The surface free energy of the CrN x films and their components (e.g., dispersion, polar) were calculated using the Owens-Wendt geometric mean approach. The influences of CrN x film surface roughness and microstructure on the surface free energy were investigated by atomic force microscopy (AFM) and X-ray diffraction (XRD), respectively. The experimental results showed that the lowest total SFE was obtained corresponding to CrN at temperature in 20 deg. C. This is lower than that of Cr(N), Cr2N (and mixture of these phases). The total SFE, dispersive SFE and polar SFE of CrN x films decreased with increasing surface temperature. The film roughness has an obvious effect on the SFE and there is tendency for the SFE to increase with increasing film surface roughness

  20. Arabidopsis GERANYLGERANYL DIPHOSPHATE SYNTHASE 11 is a hub isozyme required for the production of most photosynthesis-related isoprenoids.

    Science.gov (United States)

    Ruiz-Sola, M Águila; Coman, Diana; Beck, Gilles; Barja, M Victoria; Colinas, Maite; Graf, Alexander; Welsch, Ralf; Rütimann, Philipp; Bühlmann, Peter; Bigler, Laurent; Gruissem, Wilhelm; Rodríguez-Concepción, Manuel; Vranová, Eva

    2016-01-01

    Most plastid isoprenoids, including photosynthesis-related metabolites such as carotenoids and the side chain of chlorophylls, tocopherols (vitamin E), phylloquinones (vitamin K), and plastoquinones, derive from geranylgeranyl diphosphate (GGPP) synthesized by GGPP synthase (GGPPS) enzymes. Seven out of 10 functional GGPPS isozymes in Arabidopsis thaliana reside in plastids. We aimed to address the function of different GGPPS paralogues for plastid isoprenoid biosynthesis. We constructed a gene co-expression network (GCN) using GGPPS paralogues as guide genes and genes from the upstream and downstream pathways as query genes. Furthermore, knock-out and/or knock-down ggpps mutants were generated and their growth and metabolic phenotypes were analyzed. Also, interacting protein partners of GGPPS11 were searched for. Our data showed that GGPPS11, encoding the only plastid isozyme essential for plant development, functions as a hub gene among GGPPS paralogues and is required for the production of all major groups of plastid isoprenoids. Furthermore, we showed that the GGPPS11 protein physically interacts with enzymes that use GGPP for the production of carotenoids, chlorophylls, tocopherols, phylloquinone, and plastoquinone. GGPPS11 is a hub isozyme required for the production of most photosynthesis-related isoprenoids. Both gene co-expression and protein-protein interaction likely contribute to the channeling of GGPP by GGPPS11. PMID:26224411

  1. The ASH1 HOMOLOG 2 (ASHH2 histone H3 methyltransferase is required for ovule and anther development in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Paul E Grini

    Full Text Available BACKGROUND: SET-domain proteins are histone lysine (K methyltransferases (HMTase implicated in defining transcriptionally permissive or repressive chromatin. The Arabidopsis ASH1 HOMOLOG 2 (ASHH2 protein (also called SDG8, EFS and CCR1 has been suggested to methylate H3K4 and/or H3K36 and is similar to Drosophila ASH1, a positive maintainer of gene expression, and yeast Set2, a H3K36 HMTase. Mutation of the ASHH2 gene has pleiotropic developmental effects. Here we focus on the role of ASHH2 in plant reproduction. METHODOLOGY/PRINCIPAL FINDINGS: A slightly reduced transmission of the ashh2 allele in reciprocal crosses implied involvement in gametogenesis or gamete function. However, the main requirement of ASHH2 is sporophytic. On the female side, close to 80% of mature ovules lack embryo sac. On the male side, anthers frequently develop without pollen sacs or with specific defects in the tapetum layer, resulting in reduction in the number of functional pollen per anther by up to approximately 90%. In consistence with the phenotypic findings, an ASHH2 promoter-reporter gene was expressed at the site of megaspore mother cell formation as well as tapetum layers and pollen. ashh2 mutations also result in homeotic changes in floral organ identity. Transcriptional profiling identified more than 300 up-regulated and 600 down-regulated genes in ashh2 mutant inflorescences, whereof the latter included genes involved in determination of floral organ identity, embryo sac and anther/pollen development. This was confirmed by real-time PCR. In the chromatin of such genes (AP1, AtDMC1 and MYB99 we observed a reduction of H3K36 trimethylation (me3, but not H3K4me3 or H3K36me2. CONCLUSIONS/SIGNIFICANCE: The severe distortion of reproductive organ development in ashh2 mutants, argues that ASHH2 is required for the correct expression of genes essential to reproductive development. The reduction in the ashh2 mutant of H3K36me3 on down-regulated genes relevant to

  2. The nuclear immune receptor RPS4 is required for RRS1SLH1-dependent constitutive defense activation in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Kee Hoon Sohn

    2014-10-01

    Full Text Available Plant nucleotide-binding leucine-rich repeat (NB-LRR disease resistance (R proteins recognize specific "avirulent" pathogen effectors and activate immune responses. NB-LRR proteins structurally and functionally resemble mammalian Nod-like receptors (NLRs. How NB-LRR and NLR proteins activate defense is poorly understood. The divergently transcribed Arabidopsis R genes, RPS4 (resistance to Pseudomonas syringae 4 and RRS1 (resistance to Ralstonia solanacearum 1, function together to confer recognition of Pseudomonas AvrRps4 and Ralstonia PopP2. RRS1 is the only known recessive NB-LRR R gene and encodes a WRKY DNA binding domain, prompting suggestions that it acts downstream of RPS4 for transcriptional activation of defense genes. We define here the early RRS1-dependent transcriptional changes upon delivery of PopP2 via Pseudomonas type III secretion. The Arabidopsis slh1 (sensitive to low humidity 1 mutant encodes an RRS1 allele (RRS1SLH1 with a single amino acid (leucine insertion in the WRKY DNA-binding domain. Its poor growth due to constitutive defense activation is rescued at higher temperature. Transcription profiling data indicate that RRS1SLH1-mediated defense activation overlaps substantially with AvrRps4- and PopP2-regulated responses. To better understand the genetic basis of RPS4/RRS1-dependent immunity, we performed a genetic screen to identify suppressor of slh1 immunity (sushi mutants. We show that many sushi mutants carry mutations in RPS4, suggesting that RPS4 acts downstream or in a complex with RRS1. Interestingly, several mutations were identified in a domain C-terminal to the RPS4 LRR domain. Using an Agrobacterium-mediated transient assay system, we demonstrate that the P-loop motif of RPS4 but not of RRS1SLH1 is required for RRS1SLH1 function. We also recapitulate the dominant suppression of RRS1SLH1 defense activation by wild type RRS1 and show this suppression requires an intact RRS1 P-loop. These analyses of RRS1SLH1 shed

  3. The nuclear immune receptor RPS4 is required for RRS1SLH1-dependent constitutive defense activation in Arabidopsis thaliana.

    Science.gov (United States)

    Sohn, Kee Hoon; Segonzac, Cécile; Rallapalli, Ghanasyam; Sarris, Panagiotis F; Woo, Joo Yong; Williams, Simon J; Newman, Toby E; Paek, Kyung Hee; Kobe, Bostjan; Jones, Jonathan D G

    2014-10-01

    Plant nucleotide-binding leucine-rich repeat (NB-LRR) disease resistance (R) proteins recognize specific "avirulent" pathogen effectors and activate immune responses. NB-LRR proteins structurally and functionally resemble mammalian Nod-like receptors (NLRs). How NB-LRR and NLR proteins activate defense is poorly understood. The divergently transcribed Arabidopsis R genes, RPS4 (resistance to Pseudomonas syringae 4) and RRS1 (resistance to Ralstonia solanacearum 1), function together to confer recognition of Pseudomonas AvrRps4 and Ralstonia PopP2. RRS1 is the only known recessive NB-LRR R gene and encodes a WRKY DNA binding domain, prompting suggestions that it acts downstream of RPS4 for transcriptional activation of defense genes. We define here the early RRS1-dependent transcriptional changes upon delivery of PopP2 via Pseudomonas type III secretion. The Arabidopsis slh1 (sensitive to low humidity 1) mutant encodes an RRS1 allele (RRS1SLH1) with a single amino acid (leucine) insertion in the WRKY DNA-binding domain. Its poor growth due to constitutive defense activation is rescued at higher temperature. Transcription profiling data indicate that RRS1SLH1-mediated defense activation overlaps substantially with AvrRps4- and PopP2-regulated responses. To better understand the genetic basis of RPS4/RRS1-dependent immunity, we performed a genetic screen to identify suppressor of slh1 immunity (sushi) mutants. We show that many sushi mutants carry mutations in RPS4, suggesting that RPS4 acts downstream or in a complex with RRS1. Interestingly, several mutations were identified in a domain C-terminal to the RPS4 LRR domain. Using an Agrobacterium-mediated transient assay system, we demonstrate that the P-loop motif of RPS4 but not of RRS1SLH1 is required for RRS1SLH1 function. We also recapitulate the dominant suppression of RRS1SLH1 defense activation by wild type RRS1 and show this suppression requires an intact RRS1 P-loop. These analyses of RRS1SLH1 shed new light

  4. The Evolutionarily Conserved Protein PHOTOSYNTHESIS AFFECTED MUTANT71 Is Required for Efficient Manganese Uptake at the Thylakoid Membrane in Arabidopsis.

    Science.gov (United States)

    Schneider, Anja; Steinberger, Iris; Herdean, Andrei; Gandini, Chiara; Eisenhut, Marion; Kurz, Samantha; Morper, Anna; Hoecker, Natalie; Rühle, Thilo; Labs, Mathias; Flügge, Ulf-Ingo; Geimer, Stefan; Schmidt, Sidsel Birkelund; Husted, Søren; Weber, Andreas P M; Spetea, Cornelia; Leister, Dario

    2016-04-01

    In plants, algae, and cyanobacteria, photosystem II (PSII) catalyzes the light-driven oxidation of water. The oxygen-evolving complex of PSII is a Mn4CaO5 cluster embedded in a well-defined protein environment in the thylakoid membrane. However, transport of manganese and calcium into the thylakoid lumen remains poorly understood. Here, we show that Arabidopsis thaliana PHOTOSYNTHESIS AFFECTED MUTANT71 (PAM71) is an integral thylakoid membrane protein involved in Mn(2+) and Ca(2+) homeostasis in chloroplasts. This protein is required for normal operation of the oxygen-evolving complex (as evidenced by oxygen evolution rates) and for manganese incorporation. Manganese binding to PSII was severely reduced in pam71 thylakoids, particularly in PSII supercomplexes. In cation partitioning assays with intact chloroplasts, Mn(2+) and Ca(2+) ions were differently sequestered in pam71, with Ca(2+) enriched in pam71 thylakoids relative to the wild type. The changes in Ca(2+) homeostasis were accompanied by an increased contribution of the transmembrane electrical potential to the proton motive force across the thylakoid membrane. PSII activity in pam71 plants and the corresponding Chlamydomonas reinhardtii mutant cgld1 was restored by supplementation with Mn(2+), but not Ca(2+) Furthermore, PAM71 suppressed the Mn(2+)-sensitive phenotype of the yeast mutant Δpmr1 Therefore, PAM71 presumably functions in Mn(2+) uptake into thylakoids to ensure optimal PSII performance. PMID:27020959

  5. Integration of hormonal signaling networks and mobile microRNAs is required for vascular patterning in Arabidopsis roots

    KAUST Repository

    Muraro, D.

    2013-12-31

    As multicellular organisms grow, positional information is continually needed to regulate the pattern in which cells are arranged. In the Arabidopsis root, most cell types are organized in a radially symmetric pattern; however, a symmetry-breaking event generates bisymmetric auxin and cytokinin signaling domains in the stele. Bidirectional cross-talk between the stele and the surrounding tissues involving a mobile transcription factor, SHORT ROOT (SHR), and mobile microRNA species also determines vascular pattern, but it is currently unclear how these signals integrate. We use a multicellular model to determine a minimal set of components necessary for maintaining a stable vascular pattern. Simulations perturbing the signaling network show that, in addition to the mutually inhibitory interaction between auxin and cytokinin, signaling through SHR, microRNA165/6, and PHABULOSA is required to maintain a stable bisymmetric pattern. We have verified this prediction by observing loss of bisymmetry in shr mutants. The model reveals the importance of several features of the network, namely the mutual degradation of microRNA165/6 and PHABULOSA and the existence of an additional negative regulator of cytokinin signaling. These components form a plausible mechanism capable of patterning vascular tissues in the absence of positional inputs provided by the transport of hormones from the shoot.

  6. Induction of defence gene expression by oligogalacturonic acid requires increases in both cytosolic calcium and hydrogen peroxide in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Xiang Yang HU; Steven J NEILL; Wei Ming CAI; Zhang Cheng TANG

    2004-01-01

    Responses to oligogalacturonic acid (OGA) were determined in transgenic Arabidopsis thaliana seedlings expressing the calcium reporter protein aequorin. OGA stimulated a rapid, substantial and transient increase in the concentration of cytosolic calcium ([Ca2+]cyt) that peaked after ca. 15 s. This increase was dose-dependent, saturating at ca. 50 μg Gal equiv/ml of OGA. OGA also stimulated a rapid generation of H2O2. A small, rapid increase in H2O2 content was followed by a much larger oxidative burst, with H2O2 content peaking after ca. 60 min and declining thereafter. Induction of the oxidative burst by OGA was also dose-dependent, with a maximum response again being achieved at ca. 50 μg Gal equiv/mL. Inhibitors of calcium fluxes inhibited both increases in [Ca2+]cyt and [H2O2], whereas inhibitors of NADPH oxidase blocked only the oxidative burst. OGA increased strongly the expression of the defence-related genes CHS,GST, PAL and PR-1. This induction was suppressed by inhibitors of calcium flux or NADPH oxidase, indicating that increases in both cytosolic calcium and H2O2 are required for OGA-induced gene expression.

  7. Regulation of the New Arabidopsis Imprinted Gene AtBMI1C Requires the Interplay of Different Epigenetic Mechanisms

    Institute of Scientific and Technical Information of China (English)

    Fabian Bratzel; ChaoYang; Alexandra Ancelova; Gema López-Torrejón; Marcus Koch; Juan Carlos del Pozo; Myriam Calonje

    2012-01-01

    Recently,it has been shown that plants contain homologs to the animal Polycomb repressive complex 1 (PRC1)components BMI1 and RING1A/B.In Arabidopsis,there are three BMI1-like genes,two of which,AtBMI1A and B,are required during post-embryonic plant growth to repress embryonic traits and allow cell differentiation.However,little is known about the third BMI1-like gene,AtBMI1C.In this work,we show that AtBMI1C is only expressed during endosperm and stamen development.AtBMI1C is an imprinted gene expressed from the maternal allele in the endosperm but biallelically expressed in stamen.We found that the characteristic expression pattern of AtBMI1C is the result of a complex epigenetic regulation that involves CG DNA methylation,RNA-directed non-CG DNA methylation (RdDM),and PcG activity.Our results show the orchestrated interplay of different epigenetic mechanisms in regulating gene expression throughout development,shedding light on the current hypotheses for the origin and mechanism of imprinting in plant endosperm.

  8. Key divisions in the early Arabidopsis embryo require POL and PLL1 phosphatases to establish the root stem organizer and vascular axis

    OpenAIRE

    Song, Sang-Kee; Hofhuis, Hugo; Lee, Myeong Min; Clark, Steven E

    2008-01-01

    Arabidopsis development proceeds from three stem cell populations located at the shoot, flower and root meristems. The relationship between the highly related shoot and flower stem cells with the very divergent root stem cells has been unclear. We show that the related phosphatases POL and PLL1 are required for all three stem cell populations. pol pll1 mutant embryos lack key asymmetric divisions that give rise to the root stem cell organizer and the central vascular axis. Instead, these cell...

  9. Ku is required for telomeric C-rich strand maintenance but not for end-to-end chromosome fusions in Arabidopsis

    OpenAIRE

    Riha, Karel; Dorothy E Shippen

    2003-01-01

    Telomere dysfunction arising from mutations in telomerase or in telomere capping proteins leads to end-to-end chromosome fusions. Paradoxically, the Ku70/80 heterodimer, essential for nonhomologous end-joining double-strand break repair, is also found at telomeres, and in mammals it is required to prevent telomere fusion. Previously, we showed that inactivation of Ku70 in Arabidopsis results in telomere lengthening. Here, we have demonstrated that this telomere elongation is telomerase depend...

  10. A genetic screen for modifiers of UFO meristem activity identifies three novel FUSED FLORAL ORGANS genes required for early flower development in Arabidopsis.

    OpenAIRE

    Levin, J Z; Fletcher, J C; Chen, X.; Meyerowitz, E M

    1998-01-01

    In a screen to identify novel genes required for early Arabidopsis flower development, we isolated four independent mutations that enhance the Ufo phenotype toward the production of filamentous structures in place of flowers. The mutants fall into three complementation groups, which we have termed FUSED FLORAL ORGANS (FFO) loci. ffo mutants have specific defects in floral organ separation and/or positioning; thus, the FFO genes identify components of a boundary formation mechanism(s) acting b...

  11. Mutational definition of binding requirements of an hnRNP-like protein in Arabidopsis using fluorescence correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Leder, Verena [Molecular Cell Physiology, Faculty of Biology, Bielefeld University (Germany); Biomolecular Photonics, Faculty of Physics, Bielefeld University (Germany); Lummer, Martina [Molecular Cell Physiology, Faculty of Biology, Bielefeld University (Germany); Tegeler, Kathrin [Molecular Cell Physiology, Faculty of Biology, Bielefeld University (Germany); Biomolecular Photonics, Faculty of Physics, Bielefeld University (Germany); Humpert, Fabian [Biomolecular Photonics, Faculty of Physics, Bielefeld University (Germany); Lewinski, Martin [Molecular Cell Physiology, Faculty of Biology, Bielefeld University (Germany); Schüttpelz, Mark [Biomolecular Photonics, Faculty of Physics, Bielefeld University (Germany); Staiger, Dorothee, E-mail: dorothee.staiger@uni-bielefeld.de [Molecular Cell Physiology, Faculty of Biology, Bielefeld University (Germany)

    2014-10-10

    Highlights: • We use FCS to investigate binding site requirements for the hnRNP-like protein AtGRP7. • We identify three nucleotides critical for AtGRP7 binding to its own intron. • Mutation of the conserved R{sup 49} abolishes binding altogether. • The paralogue AtGRP8 binds to an overlapping motif with different sequence requirement. • The glycine-rich stretch of a plant hnRNP-like protein contributes to binding. - Abstract: Arabidopsis thaliana glycine-rich RNA binding protein 7 (AtGRP7) is part of a negative feedback loop through which it regulates alternative splicing and steady-state abundance of its pre-mRNA. Here we use fluorescence correlation spectroscopy to investigate the requirements for AtGRP7 binding to its intron using fluorescently-labelled synthetic oligonucleotides. By systematically introducing point mutations we identify three nucleotides that lead to an increased K{sub d} value when mutated and thus are critical for AtGRP7 binding. Simultaneous mutation of all three residues abrogates binding. The paralogue AtGRP8 binds to an overlapping motif but with a different sequence preference, in line with overlapping but not identical functions of this protein pair. Truncation of the glycine-rich domain reduces the binding affinity of AtGRP7, showing for the first time that the glycine-rich stretch of a plant hnRNP-like protein contributes to binding. Mutation of the conserved R{sup 49} that is crucial for AtGRP7 function in pathogen defence and splicing abolishes binding.

  12. Mutational definition of binding requirements of an hnRNP-like protein in Arabidopsis using fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Highlights: • We use FCS to investigate binding site requirements for the hnRNP-like protein AtGRP7. • We identify three nucleotides critical for AtGRP7 binding to its own intron. • Mutation of the conserved R49 abolishes binding altogether. • The paralogue AtGRP8 binds to an overlapping motif with different sequence requirement. • The glycine-rich stretch of a plant hnRNP-like protein contributes to binding. - Abstract: Arabidopsis thaliana glycine-rich RNA binding protein 7 (AtGRP7) is part of a negative feedback loop through which it regulates alternative splicing and steady-state abundance of its pre-mRNA. Here we use fluorescence correlation spectroscopy to investigate the requirements for AtGRP7 binding to its intron using fluorescently-labelled synthetic oligonucleotides. By systematically introducing point mutations we identify three nucleotides that lead to an increased Kd value when mutated and thus are critical for AtGRP7 binding. Simultaneous mutation of all three residues abrogates binding. The paralogue AtGRP8 binds to an overlapping motif but with a different sequence preference, in line with overlapping but not identical functions of this protein pair. Truncation of the glycine-rich domain reduces the binding affinity of AtGRP7, showing for the first time that the glycine-rich stretch of a plant hnRNP-like protein contributes to binding. Mutation of the conserved R49 that is crucial for AtGRP7 function in pathogen defence and splicing abolishes binding

  13. Argon irradiation effects on the structural and optical properties of reactively sputtered CrN films

    OpenAIRE

    Novaković M.; Popović M.; Bibić N.

    2015-01-01

    The present study deals with CrN films irradiated at room temperature (RT) with 200 keV Ar+ ions. The CrN layers were deposited by d.c. reactive sputtering on Si (100) wafers, at nitrogen partial pressure of 5×10-4 mbar, to a total thickness of 280 nm. The substrates were held at 150ºC during deposition. After deposition the CrN layers were irradiated with 200 keV Ar+ ions to the fluences of 5×1015 - 2×1016 ions/cm2. Structural characterization was performe...

  14. The AP-3 adaptor complex is required for vacuolar function in Arabidopsis

    NARCIS (Netherlands)

    Zwiewka, M.; Feraru, E.; Moller, B.K.; Hwang, I.; Feraru, M.I.; Kleine-Vehn, J.; Weijers, D.; Friml, J.

    2011-01-01

    Subcellular trafficking is required for a multitude of functions in eukaryotic cells. It involves regulation of cargo sorting, vesicle formation, trafficking and fusion processes at multiple levels. Adaptor protein (AP) complexes are key regulators of cargo sorting into vesicles in yeast and mammals

  15. Performance analyses of wormhole attack in Cognitive Radio Network (CRN

    Directory of Open Access Journals (Sweden)

    Prabhjot

    2015-06-01

    Full Text Available Mobile wirelesses networks are generally open to various attacks like information and physical security attacks than fixed wired networks. Securing wireless ad hoc networks is particularly more difficult for many of the reasons for example vulnerability of channels and nodes, absence of infrastructure, dynamically changing topology etc. After that we initialize the number of nodes. Then implement protocol for the communication of nodes. Due to these protocols communication start. And this will be then implemented in CRNs which stand for cognitive radio network in which channel sensing is done. By the use of CRN security will be improved and performance will be enhanced. Find the malicious nodes occur in the network. One malicious node uses routing protocol to claim itself of being shortest path to last node but drops routing packets and doesn’t send packets to its neighbors. In last evaluate the parameters.

  16. The WIGGUM gene is required for proper regulation of floral meristem size in Arabidopsis

    OpenAIRE

    Running, Mark P; Fletcher, Jennifer C; Meyerowitz, Elliot M.

    1998-01-01

    The study of cell division control within developing tissues is central to understanding the processes of pattern formation. The floral meristem of angiosperms gives rise to floral organs in a particular number and pattern. Despite its critical role, little is known about how cell division is controlled in the floral meristem, and few genes involved have been identified. We describe the phenotypic effects of mutations in WIGGUM, a gene required for control of cell proliferation in the floral ...

  17. Plastid chaperonin proteins Cpn60α and Cpn60β are required for plastid division in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Osteryoung Katherine W

    2009-04-01

    Full Text Available Abstract Background Plastids arose from a free-living cyanobacterial endosymbiont and multiply by binary division as do cyanobacteria. Plastid division involves nucleus-encoded homologs of cyanobacterial division proteins such as FtsZ, MinD, MinE, and ARC6. However, homologs of many other cyanobacterial division genes are missing in plant genomes and proteins of host eukaryotic origin, such as a dynamin-related protein, PDV1 and PDV2 are involved in the division process. Recent identification of plastid division proteins has started to elucidate the similarities and differences between plastid division and cyanobacterial cell division. To further identify new proteins that are required for plastid division, we characterized previously and newly isolated plastid division mutants of Arabidopsis thaliana. Results Leaf cells of two mutants, br04 and arc2, contain fewer, larger chloroplasts than those of wild type. We found that ARC2 and BR04 are identical to nuclear genes encoding the plastid chaperonin 60α (ptCpn60α and chaperonin 60β (ptCpn60β proteins, respectively. In both mutants, plastid division FtsZ ring formation was partially perturbed though the level of FtsZ2-1 protein in plastids of ptcpn60β mutants was similar to that in wild type. Phylogenetic analyses showed that both ptCpn60 proteins are derived from ancestral cyanobacterial proteins. The A. thaliana genome encodes two members of ptCpn60α family and four members of ptCpn60β family respectively. We found that a null mutation in ptCpn60α abolished greening of plastids and resulted in an albino phenotype while a weaker mutation impairs plastid division and reduced chlorophyll levels. The functions of at least two ptCpn60β proteins are redundant and the appearance of chloroplast division defects is dependent on the number of mutant alleles. Conclusion Our results suggest that both ptCpn60α and ptCpn60β are required for the formation of a normal plastid division apparatus, as

  18. Shade avoidance 6 encodes an Arabidopsis flap endonuclease required for maintenance of genome integrity and development.

    Science.gov (United States)

    Zhang, Yijuan; Wen, Chunhong; Liu, Songbai; Zheng, Li; Shen, Binghui; Tao, Yi

    2016-02-18

    Flap endonuclease-1 (FEN1) belongs to the Rad2 family of structure-specific nucleases. It is required for several DNA metabolic pathways, including DNA replication and DNA damage repair. Here, we have identified a shade avoidance mutant, sav6, which reduces the mRNA splicing efficiency of SAV6. We have demonstrated that SAV6 is an FEN1 homologue that shows double-flap endonuclease and gap-dependent endonuclease activity, but lacks exonuclease activity. sav6 mutants are hypersensitive to DNA damage induced by ultraviolet (UV)-C radiation and reagents that induce double-stranded DNA breaks, but exhibit normal responses to chemicals that block DNA replication. Signalling components that respond to DNA damage are constitutively activated in sav6 mutants. These data indicate that SAV6 is required for DNA damage repair and the maintenance of genome integrity. Mutant sav6 plants also show reduced root apical meristem (RAM) size and defective quiescent centre (QC) development. The expression of SMR7, a cell cycle regulatory gene, and ERF115 and PSK5, regulators of QC division, is increased in sav6 mutants. Their constitutive induction is likely due to the elevated DNA damage responses in sav6 and may lead to defects in the development of the RAM and QC. Therefore, SAV6 assures proper root development through maintenance of genome integrity. PMID:26721386

  19. A comparative study of eld emission properties of Cu, Cr, and CrN

    CERN Document Server

    Muranaka, T; Leifer, K; Ziemann, V

    2012-01-01

    We investigated the field emission properties of Cu, Cr, and CrN by using the field emission measurement setup inside a scanning electron microscope at the Angstrom laboratory in Uppsala University, from 11th to 13th January 2012.

  20. Electrochemical behavior of CrN coating for polymer electrolyte membrane fuel cell

    International Nuclear Information System (INIS)

    CrN films on a bipolar plate in polymer electrolyte membrane fuel cells have several advantages owing to their excellent corrosion resistance and mechanical properties. Three CrN samples deposited at various radio frequency (RF) powers by RF magnetron sputtering were evaluated under potentiodynamic, potentiostatic and electrochemical impedance spectroscopy conditions. The electrochemical impedance spectroscopy data were monitored for 168 h in a corrosive environment at 70 0C to determine the coating performance at +600 mVSCE under simulated cathodic conditions in a polymer electrolyte membrane fuel cell. The electrochemical behavior of the coatings increased with decreasing RF power. CrN films on the AISI 316 stainless steel substrate showed high protective efficiency and charge transfer resistance, i.e. increasing corrosion resistance with decreasing RF power. X-ray diffraction confirmed the formation of a CrN(200) preferred orientation at low RF power.

  1. SPATULA and ALCATRAZ, are partially redundant, functionally diverging bHLH genes required for Arabidopsis gynoecium and fruit development.

    Science.gov (United States)

    Groszmann, Michael; Paicu, Teodora; Alvarez, John P; Swain, Steve M; Smyth, David R

    2011-12-01

    The Arabidopsis gynoecium is a complex organ that facilitates fertilization, later developing into a dehiscent silique that protects seeds until their dispersal. Identifying genes important for development is often hampered by functional redundancy. We report unequal redundancy between two closely related genes, SPATULA (SPT) and ALCATRAZ (ALC), revealing previously unknown developmental roles for each. SPT is known to support septum, style and stigma development in the flower, whereas ALC is involved in dehiscence zone development in the fruit. ALC diverged from a SPT-like ancestor following gene duplication coinciding with the At-β polyploidy event. Here we show that ALC is also involved in early gynoecium development, and SPT in later valve margin generation in the silique. Evidence includes the increased severity of early gynoecium disruption, and of later valve margin defects, in spt-alc double mutants. In addition, a repressive version of SPT (35S:SPT-SRDX) disrupts both structures. Consistent with redundancy, ALC and SPT expression patterns overlap in these tissues, and the ALC promoter carries two atypical E-box elements identical to one in SPT required for valve margin expression. Further, SPT can heterodimerize with ALC, and 35S:SPT can fully complement dehiscence defects in alc mutants, although 35S:ALC can only partly complement spt gynoecium disruptions, perhaps associated with its sequence simplification. Interactions with FRUITFULL and SHATTERPROOF genes differ somewhat between SPT and ALC, reflecting their different specializations. These two genes are apparently undergoing subfunctionalization, with SPT essential for earlier carpel margin tissues, and ALC specializing in later dehiscence zone development. PMID:21801252

  2. Phytophthora sojae Effector PsCRN70 Suppresses Plant Defenses in Nicotiana benthamiana

    OpenAIRE

    Rajput, Nasir Ahmed; Zhang, Meixiang; Ru, Yanyan; Liu, Tingli; Xu, Jing; Li LIU; Mafurah, Joseph Juma; Dou, Daolong

    2014-01-01

    Phytophthora sojae, an oomycete pathogen, produces a large number of effector proteins that enter into host cells. The Crinklers (Crinkling and Necrosis, CRN) are cytoplasmic effectors that are conserved in oomycete pathogens and their encoding genes are highly expressed at the infective stages in P. sojae. However, their roles in pathogenesis are largely unknown. Here, we functionally characterized an effector PsCRN70 by transiently and stably overexpressing it in Nicotiana benthamiana. We d...

  3. Electronic structure of CrN: A comparison between different exchange correlation potentials

    OpenAIRE

    Botana, A. S.; Tran, F.; Pardo, V.; Baldomir, D.; Blaha, P.

    2012-01-01

    We report a series of electronic structure calculations for CrN using different exchange correlation potentials: PBE, LDA+$U$, the Tran-Blaha modified Becke-Johnson, and hybrid functionals. In every case, our calculations show that the onset of magnetism in CrN should be accompanied by a gap opening. The experimentally found antiferromagnetic order always leads to an insulating behavior. Our results give further evidence that the Tran-Blaha functional is very useful for treating the electroni...

  4. Plasma deposition of CrN and CrTiALN films

    International Nuclear Information System (INIS)

    CrN and CrTiAlN coatings were deposited on Si, high-speed steels and WC by electron source assisted medium-frequency magnetron sputtering. The influence of gas flow rate, negative bias voltage, and sputtering power on the structure and mechanical properties of CrN and CrTiAlN coatings were studied. (1) X-ray diffraction showed that CrN coatings deposited at N2/( N2+Ar) ratios below 60% were polycrystalline with a CrN (200) orientation whereas those prepared at higher N2/( N2+Ar) ratios showed Cr2N structure. The deposition rate of CrN was in the range of 8.5-12.5 m/h and their microhardness was in the range of 10-18 GPa. (2) The deposition rate, structure, and microhardness of the coatings were strongly influenced by the negative bias voltage. At bias voltage lower than 25 V both CrN (200) and (111) were observed. AFM and SEM showed that the samples exhibited a fibrous structure, whereas at bias voltage exceeding 25 V the samples showed a columnar structure. (3) For CrTiAlN coatings prepared at -200 V the microhardness was 28.5 GPa and the average coefficient friction against Si3N4 ball was 0.7, and the corresponding wear rate was 3.6 x 10-15 m3/N·m. The maximum hardness was 29 Gpa and the lowest friction coefficient was 0.37. The corrosion resistance of high-speed steels coated with CrN, CrTiAlN coatings was improved, with CrTiAlN being superior to CrN. (authors)

  5. Of the Nine Cytidine Deaminase-Like Genes in Arabidopsis, Eight Are Pseudogenes and Only One Is Required to Maintain Pyrimidine Homeostasis in Vivo.

    Science.gov (United States)

    Chen, Mingjia; Herde, Marco; Witte, Claus-Peter

    2016-06-01

    CYTIDINE DEAMINASE (CDA) catalyzes the deamination of cytidine to uridine and ammonia in the catabolic route of C nucleotides. The Arabidopsis (Arabidopsis thaliana) CDA gene family comprises nine members, one of which (AtCDA) was shown previously in vitro to encode an active CDA. A possible role in C-to-U RNA editing or in antiviral defense has been discussed for other members. A comprehensive bioinformatic analysis of plant CDA sequences, combined with biochemical functionality tests, strongly suggests that all Arabidopsis CDA family members except AtCDA are pseudogenes and that most plants only require a single CDA gene. Soybean (Glycine max) possesses three CDA genes, but only two encode functional enzymes and just one has very high catalytic efficiency. AtCDA and soybean CDAs are located in the cytosol. The functionality of AtCDA in vivo was demonstrated with loss-of-function mutants accumulating high amounts of cytidine but also CMP, cytosine, and some uridine in seeds. Cytidine hydrolysis in cda mutants is likely caused by NUCLEOSIDE HYDROLASE1 (NSH1) because cytosine accumulation is strongly reduced in a cda nsh1 double mutant. Altered responses of the cda mutants to fluorocytidine and fluorouridine indicate that a dual specific nucleoside kinase is involved in cytidine as well as uridine salvage. CDA mutants display a reduction in rosette size and have fewer leaves compared with the wild type, which is probably not caused by defective pyrimidine catabolism but by the accumulation of pyrimidine catabolism intermediates reaching toxic concentrations. PMID:27208239

  6. A new role for an old enzyme: Nitrate reductase-mediated nitric oxide generation is required for abscisic acid-induced stomatal closure in Arabidopsis thaliana

    Science.gov (United States)

    Desikan, Radhika; Griffiths, Rachael; Hancock, John; Neill, Steven

    2002-01-01

    The plant hormone abscisic acid (ABA), synthesized in response to water-deficit stress, induces stomatal closure via activation of complex signaling cascades. Recent work has established that nitric oxide (NO) is a key signaling molecule mediating ABA-induced stomatal closure. However, the biosynthetic origin of NO in guard cells has not yet been resolved. Here, we provide pharmacological, physiological, and genetic evidence that NO synthesis in Arabidopsis guard cells is mediated by the enzyme nitrate reductase (NR). Guard cells of wild-type Arabidopsis generate NO in response to treatment with ABA and nitrite, a substrate for NR. Moreover, NR-mediated NO synthesis is required for ABA-induced stomatal closure. However, in the NR double mutant, nia1, nia2 that has diminished NR activity, guard cells do not synthesize NO nor do the stomata close in response to ABA or nitrite, although stomatal opening is still inhibited by ABA. Furthermore, by using the ABA-insensitive (ABI) abi1–1 and abi2–1 mutants, we show that the ABI1 and ABI2 protein phosphatases are downstream of NO in the ABA signal-transduction cascade. These data demonstrate a previously uncharacterized signaling role for NR, that of mediating ABA-induced NO synthesis in Arabidopsis guard cells. PMID:12446847

  7. The AP-3 adaptor complex is required for vacuolar function in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Maria Zwiewka; Elena Feraru; Barbara M(o)ller; Inhwan Hwang; Mugurel I Feraru; Jürgen Kleine-Vehn; Dolf Weijers; Ji(n) Friml

    2011-01-01

    Subcellular trafficking is required for a multitude of functions in eukaryotic cells.It involves regulation of cargo sorting,vesicle formation,trafficking and fusion processes at multiple levels.Adaptor protein (AP) complexes are key regulators of cargo sorting into vesicles in yeast and mammals but their existence and function in plants have not been demonstrated.Here we report the identification of the protein-affected trafficking 4 (pat4) mutant defective in the putative δ subunit of the AP-3 complex.pat4 and pat2,a mutant isolated from the same GFP imaging-based forward genetic screen that lacks a functional putative AP-3 β,as well as dominant negative AP-3 μ transgenic lines display undistinguishable phenotypes characterized by largely normal morphology and development,but strong intracellular accumulation of membrane proteins in aberrant vacuolar structures.All mutants are defective in morphology and function of lytic and protein storage vacuoles (PSVs) but show normal sorting of reserve proteins to PSVs.Immunoprecipitation experiments and genetic studies revealed tight functional and physical associations of putative AP-3 β and AP-3 δ subunits.Furthermore,both proteins are closely linked with putative AP-3 μ and σ subunits and several components of the clathrin and dynamin machineries.Taken together,these results demonstrate that AP complexes,similar to those in other eukaryotes,exist in plants,and that AP-3 plays a specific role in the regulation of biogenesis and function of vacuoles in plant cells.

  8. Computational simulation of the CrN - FCC structure; Simulación computacional de la estructura FCC del CrN

    Directory of Open Access Journals (Sweden)

    ALEXANDER RUDEN MUÑOZ

    2013-06-01

    Full Text Available CrN thin films were synthesized via Magnetron Sputtering deposition technique on (111 oriented Silicon substrates. Coatings were analyzed by using X-ray Diffraction (XRD and Raman spectroscopy, determining the cubic phase for the ceramic compound. Computational simulation of the CrN cubic crystallographic structure, performed by using Density Functional Theory (DFT, showed stability by the sum of Mulliquen charges equal to zero and compound hybridization with characteristic sp molecular orbitals and the identification of the p molecular orbital component from the nitrogen.

  9. The Arabidopsis ISR1 locus is required for rhizobacteria-mediated induced systemic resistance against different pathogens

    NARCIS (Netherlands)

    Ton, J.; Pelt, J.A. van; Loon, L.C. van; Pieterse, C.M.J.

    2002-01-01

    In Arabidopsis thaliana, non-pathogenic, root-colonizing Pseudomonas fluorescens WCS417r bacteria trigger an induced systemic resistance (ISR) that is phenotypically similar to pathogen-induced systemic acquired resistance (SAR). In contrast to SAR, WCS417r-mediated ISR is controlled by a salicylic

  10. A Virulence Essential CRN Effector of Phytophthora capsici Suppresses Host Defense and Induces Cell Death in Plant Nucleus

    OpenAIRE

    Mafurah, Joseph Juma; Ma, Huifei; Zhang, Meixiang; Xu, Jing; HE Feng; Ye, Tingyue; Shen, Danyu; Yanyu CHEN; Rajput, Nasir Ahmed; Dou, Daolong

    2015-01-01

    Phytophthora capsici is a soil-borne plant pathogen with a wide range of hosts. The pathogen secretes a large array of effectors during infection of host plants, including Crinkler (CRN) effectors. However, it remains largely unknown on the roles of these effectors in virulence especially in P. capsici. In this study, we identified a cell death-inducing CRN effector PcCRN4 using agroinfiltration approach. Transient expression of PcCRN4 gene induced cell death in N. benthamiana, N. tabacum and...

  11. Nanostructured CrN thin films prepared by reactive pulsed DC magnetron sputtering

    International Nuclear Information System (INIS)

    High quality chromium nitride (CrN) films have been deposited onto silicon (1 0 0) substrates using pulsed DC magnetron sputtering of pure Cr target at different gas mixtures of argon and nitrogen and in the substrate temperature range 303-973 K. At low N2 flow rates (2N and CrN) are obtained. At higher flow rates, in the range of 10-25 sccm, only cubic CrN phase is obtained. The films prepared at different substrate temperatures and at 10 sccm of nitrogen flow rate indicated the formation of cubic CrN phase at room temperature and the phase formed is found to be stable up to 973 K. The deposition of the films as a function of nitrogen flow rate and substrate temperatures indicated that the good quality crystalline films could be formed at 773 K, 10 sccm of nitrogen flow rate. The Cr 2p3/2 and N 1s of XPS spectra also confirmed the formation of CrN phase. Determination of the texture coefficients of the CrN films as a function of substrate temperature showed that the preferred orientation changes from [1 1 1] to [1 0 0]. Deposition as a function of nitrogen flow rates and substrate temperatures showed significant changes in the morphology and RMS surface roughness, which could be related to the difference in the growth mechanism of the CrN films. Measurement of nanomechanical properties on typical films deposited on titanium modified stainless steel substrates at optimum conditions show hardness of 12 ± 1.81 GPa, Young's modulus of about (250 ± 51.28 GPa) and coefficient of friction of 0.16.

  12. A Specialized Histone H1 Variant Is Required for Adaptive Responses to Complex Abiotic Stress and Related DNA Methylation in Arabidopsis.

    Science.gov (United States)

    Rutowicz, Kinga; Puzio, Marcin; Halibart-Puzio, Joanna; Lirski, Maciej; Kotliński, Maciej; Kroteń, Magdalena A; Knizewski, Lukasz; Lange, Bartosz; Muszewska, Anna; Śniegowska-Świerk, Katarzyna; Kościelniak, Janusz; Iwanicka-Nowicka, Roksana; Buza, Krisztián; Janowiak, Franciszek; Żmuda, Katarzyna; Jõesaar, Indrek; Laskowska-Kaszub, Katarzyna; Fogtman, Anna; Kollist, Hannes; Zielenkiewicz, Piotr; Tiuryn, Jerzy; Siedlecki, Paweł; Swiezewski, Szymon; Ginalski, Krzysztof; Koblowska, Marta; Archacki, Rafał; Wilczynski, Bartek; Rapacz, Marcin; Jerzmanowski, Andrzej

    2015-11-01

    Linker (H1) histones play critical roles in chromatin compaction in higher eukaryotes. They are also the most variable of the histones, with numerous nonallelic variants cooccurring in the same cell. Plants contain a distinct subclass of minor H1 variants that are induced by drought and abscisic acid and have been implicated in mediating adaptive responses to stress. However, how these variants facilitate adaptation remains poorly understood. Here, we show that the single Arabidopsis (Arabidopsis thaliana) stress-inducible variant H1.3 occurs in plants in two separate and most likely autonomous pools: a constitutive guard cell-specific pool and a facultative environmentally controlled pool localized in other tissues. Physiological and transcriptomic analyses of h1.3 null mutants demonstrate that H1.3 is required for both proper stomatal functioning under normal growth conditions and adaptive developmental responses to combined light and water deficiency. Using fluorescence recovery after photobleaching analysis, we show that H1.3 has superfast chromatin dynamics, and in contrast to the main Arabidopsis H1 variants H1.1 and H1.2, it has no stable bound fraction. The results of global occupancy studies demonstrate that, while H1.3 has the same overall binding properties as the main H1 variants, including predominant heterochromatin localization, it differs from them in its preferences for chromatin regions with epigenetic signatures of active and repressed transcription. We also show that H1.3 is required for a substantial part of DNA methylation associated with environmental stress, suggesting that the likely mechanism underlying H1.3 function may be the facilitation of chromatin accessibility by direct competition with the main H1 variants. PMID:26351307

  13. A Specialized Histone H1 Variant Is Required for Adaptive Responses to Complex Abiotic Stress and Related DNA Methylation in Arabidopsis1[OPEN

    Science.gov (United States)

    Rutowicz, Kinga; Puzio, Marcin; Halibart-Puzio, Joanna; Lirski, Maciej; Kotliński, Maciej; Kroteń, Magdalena A.; Knizewski, Lukasz; Lange, Bartosz; Muszewska, Anna; Śniegowska-Świerk, Katarzyna; Kościelniak, Janusz; Iwanicka-Nowicka, Roksana; Buza, Krisztián; Janowiak, Franciszek; Żmuda, Katarzyna; Jõesaar, Indrek; Laskowska-Kaszub, Katarzyna; Fogtman, Anna; Kollist, Hannes; Zielenkiewicz, Piotr; Tiuryn, Jerzy; Siedlecki, Paweł; Swiezewski, Szymon; Ginalski, Krzysztof; Koblowska, Marta; Archacki, Rafał; Wilczynski, Bartek; Rapacz, Marcin; Jerzmanowski, Andrzej

    2015-01-01

    Linker (H1) histones play critical roles in chromatin compaction in higher eukaryotes. They are also the most variable of the histones, with numerous nonallelic variants cooccurring in the same cell. Plants contain a distinct subclass of minor H1 variants that are induced by drought and abscisic acid and have been implicated in mediating adaptive responses to stress. However, how these variants facilitate adaptation remains poorly understood. Here, we show that the single Arabidopsis (Arabidopsis thaliana) stress-inducible variant H1.3 occurs in plants in two separate and most likely autonomous pools: a constitutive guard cell-specific pool and a facultative environmentally controlled pool localized in other tissues. Physiological and transcriptomic analyses of h1.3 null mutants demonstrate that H1.3 is required for both proper stomatal functioning under normal growth conditions and adaptive developmental responses to combined light and water deficiency. Using fluorescence recovery after photobleaching analysis, we show that H1.3 has superfast chromatin dynamics, and in contrast to the main Arabidopsis H1 variants H1.1 and H1.2, it has no stable bound fraction. The results of global occupancy studies demonstrate that, while H1.3 has the same overall binding properties as the main H1 variants, including predominant heterochromatin localization, it differs from them in its preferences for chromatin regions with epigenetic signatures of active and repressed transcription. We also show that H1.3 is required for a substantial part of DNA methylation associated with environmental stress, suggesting that the likely mechanism underlying H1.3 function may be the facilitation of chromatin accessibility by direct competition with the main H1 variants. PMID:26351307

  14. Transgenerational adaptation of Arabidopsis to stress requires DNA methylation and the function of Dicer-like proteins.

    Directory of Open Access Journals (Sweden)

    Alex Boyko

    Full Text Available Epigenetic states and certain environmental responses in mammals and seed plants can persist in the next sexual generation. These transgenerational effects have potential adaptative significance as well as medical and agronomic ramifications. Recent evidence suggests that some abiotic and biotic stress responses of plants are transgenerational. For example, viral infection of tobacco plants and exposure of Arabidopsis thaliana plants to UVC and flagellin can induce transgenerational increases in homologous recombination frequency (HRF. Here we show that exposure of Arabidopsis plants to stresses, including salt, UVC, cold, heat and flood, resulted in a higher HRF, increased global genome methylation, and higher tolerance to stress in the untreated progeny. This transgenerational effect did not, however, persist in successive generations. Treatment of the progeny of stressed plants with 5-azacytidine was shown to decrease global genomic methylation and enhance stress tolerance. Dicer-like (DCL 2 and DCL3 encode Dicer activities important for small RNA-dependent gene silencing. Stress-induced HRF and DNA methylation were impaired in dcl2 and dcl3 deficiency mutants, while in dcl2 mutants, only stress-induced stress tolerance was impaired. Our results are consistent with the hypothesis that stress-induced transgenerational responses in Arabidopsis depend on altered DNA methylation and smRNA silencing pathways.

  15. Study on the structure and tribological properties of CrN coating by IBED

    Energy Technology Data Exchange (ETDEWEB)

    Bin Tang [Taiyuan Univ. of Technol., Taiyuan (China). Res. Inst. of Surface Eng.; Xiaodong Zhu; Naisai Hu; Jiawen He [State Key Lab. for Mechanical Behavior of Materials, Xi' an Jiaotong Univ. (China)

    2000-09-01

    CrN coatings were synthesized with different levels of bombarding energy by nitrogen ions with very low N ion/Cr atom arrival ratios. The structures and compositions of these coatings were investigated by XRD, XPS and AES. The tribological properties of the coatings on AISI 52 100 steel were evaluated by ball-on-disc tests. Results indicate that the fraction of the CrN phase increases with increasing bombarding energy from 4 to 8 to 12 keV, and reaches a predominant state. For the 4 keV coating, the Cr/N ratio was >1, which indicates that Cr is involved in the coating layer. The 8 and 12 keV coatings were free of Cr phase. However, the optimum N ion/Cr atom ratio for the coating is far from the stoichiometry of 1:1 Cr/N. The tribological properties of CrN coatings with different processing parameters show that the wear mechanisms of coating/substrate systems are micro-ploughing and spalling. The films processed at a low energy level and with a low N ion/C atom ratio in this study show better tribological properties and higher fracture toughness. (orig.)

  16. Transmission electron microscopy characterization of CrN films on MgO(001)

    International Nuclear Information System (INIS)

    Two CrN(001) films with different thickness were grown on MgO(001) substrates using unbalanced d.c. magnetron sputtering. The morphology and interfacial structure of the films are characterized by using conventional transmission electron microscopy, weak-beam dark-field microscopy and spherical aberration (CS)-corrected high-resolution transmission electron microscopy. The microscopy studies revealed the well-known cube-on-cube orientation relationship. While an interface dislocation network with b→=½aCrN<100> edge dislocations was identified, only part of the lattice mismatch is relaxed. The misfit dislocation structure and growth defects are analyzed and discussed based on the weak-beam dark-field and high-resolution transmission electron microscopy results. - Highlights: • Two CrN films were sputtered on MgO(001) substrates under various deposition conditions. • The CrN films nucleate epitaxially with a cube-on-cube orientation relationship. • Transmission electron microscopy shows the existence of interface dislocation networks. • The misfit between the CrN films and MgO substrates is only partially relaxed. • CrN deposition at higher bias voltage leads to an increased defect density

  17. Irradiation induced formation of VN in CrN thin films

    International Nuclear Information System (INIS)

    Highlights: • Formation of VN in CrN layer by using ion implantation was investigated. • CrN layer was implanted with 80-keV V+ ions and then annealed for 2 h at 700 °C. • VN nanoparticles were formed inside the vanadium-rich zone of the layer. • The nanoparticles are spherical shaped with diameter from 8 to 20 nm. - Abstract: Reactively sputtered CrN layer, deposited on Si(1 0 0) wafer, was implanted at room temperature with 80-keV V+ ions to the fluence of 2 × 1017 ions/cm2. After implantation the sample was annealed in a vacuum, for 2 h at 700 °C. The microstructure and chemical composition of CrN films was investigated using Rutherford backscattering spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and cross-sectional transmission electron microscopy (conventional and high-resolution), together with fast Fourier transformation analyses. It was found that vanadium atoms are distributed in the sub-surface region of CrN layer, with the maximum concentration at ∼20 nm. After annealing the formation of VN nanoparticles was observed. The nanoparticles are spherical shaped with a size of 8–20 nm in diameter

  18. Effects of MEVVA-implanted chromium on the structure and properties of CrN film

    International Nuclear Information System (INIS)

    The effect of a metal vapor vacuum arc (MEVVA)-implanted Cr interlayer on the microstructure of the CrN coating on the silicon wafer was investigated. Two types of the CrN-coated specimens were prepared with and without an MEVVA-implanted Cr interlayer--CrN/Cr/Si and CrN/Si--by cathodic arc plasma deposition. Both specimens of the same batch were annealed at 500 deg. C for 2 h in an N2/H2 atmosphere, to elucidate the thermal stability of the CrN film. The columnar structure of CrN/Cr/Si was observed by cross-sectional transmission electron microscopy. The X-ray diffraction results revealed the presence of CrN, and that (2 2 0) is the preferred orientation of both CrN/Si and CrN/Cr/Si. However, CrN/Si revealed a phase transformation from CrN to Cr2N during annealing, which is due largely to stress relaxation in the film. A MEVVA-implanted Cr interlayer can effectively relax the residual stress in the growing CrN of the coating and prevent a phase transformation in the CrN/Cr/Si assembly during annealing

  19. Irradiation induced formation of VN in CrN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Novaković, M., E-mail: mnovakov@vinca.rs [University of Belgrade, VINČA Institute of Nuclear Sciences, 11001 Belgrade (Serbia); Popović, M. [University of Belgrade, VINČA Institute of Nuclear Sciences, 11001 Belgrade (Serbia); Zhang, K. [II. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Mitrić, M.; Bibić, N. [University of Belgrade, VINČA Institute of Nuclear Sciences, 11001 Belgrade (Serbia)

    2015-09-01

    Highlights: • Formation of VN in CrN layer by using ion implantation was investigated. • CrN layer was implanted with 80-keV V{sup +} ions and then annealed for 2 h at 700 °C. • VN nanoparticles were formed inside the vanadium-rich zone of the layer. • The nanoparticles are spherical shaped with diameter from 8 to 20 nm. - Abstract: Reactively sputtered CrN layer, deposited on Si(1 0 0) wafer, was implanted at room temperature with 80-keV V{sup +} ions to the fluence of 2 × 10{sup 17} ions/cm{sup 2}. After implantation the sample was annealed in a vacuum, for 2 h at 700 °C. The microstructure and chemical composition of CrN films was investigated using Rutherford backscattering spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and cross-sectional transmission electron microscopy (conventional and high-resolution), together with fast Fourier transformation analyses. It was found that vanadium atoms are distributed in the sub-surface region of CrN layer, with the maximum concentration at ∼20 nm. After annealing the formation of VN nanoparticles was observed. The nanoparticles are spherical shaped with a size of 8–20 nm in diameter.

  20. MCM8 is required for a pathway of meiotic double-strand break repair independent of DMC1 in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Wayne Crismani

    Full Text Available Mini-chromosome maintenance (MCM 2-9 proteins are related helicases. The first six, MCM2-7, are essential for DNA replication in all eukaryotes. In contrast, MCM8 is not always conserved in eukaryotes but is present in Arabidopsis thaliana. MCM8 is required for 95% of meiotic crossovers (COs in Drosophila and is essential for meiosis completion in mouse, prompting us to study this gene in Arabidopsis meiosis. Three allelic Atmcm8 mutants showed a limited level of chromosome fragmentation at meiosis. This defect was dependent on programmed meiotic double-strand break (DSB formation, revealing a role for AtMCM8 in meiotic DSB repair. In contrast, CO formation was not affected, as shown both genetically and cytologically. The Atmcm8 DSB repair defect was greatly amplified in the absence of the DMC1 recombinase or in mutants affected in DMC1 dynamics (sds, asy1. The Atmcm8 fragmentation defect was also amplified in plants heterozygous for a mutation in either recombinase, DMC1 or RAD51. Finally, in the context of absence of homologous chromosomes (i.e. haploid, mutation of AtMCM8 also provoked a low level of chromosome fragmentation. This fragmentation was amplified by the absence of DMC1 showing that both MCM8 and DMC1 can promote repair on the sister chromatid in Arabidopsis haploids. Altogether, this establishes a role for AtMCM8 in meiotic DSB repair, in parallel to DMC1. We propose that MCM8 is involved with RAD51 in a backup pathway that repairs meiotic DSB without giving CO when the major pathway, which relies on DMC1, fails.

  1. SDG2-Mediated H3K4 Methylation Is Required for Proper Arabidopsis Root Growth and Development

    OpenAIRE

    Xiaozhen Yao; Haiyang Feng; Yu Yu; Aiwu Dong; Wen-Hui Shen

    2013-01-01

    Trithorax group (TrxG) proteins are evolutionarily conserved in eukaryotes and play critical roles in transcriptional activation via deposition of histone H3 lysine 4 trimethylation (H3K4me3) in chromatin. Several Arabidopsis TrxG members have been characterized, and among them SET DOMAIN GROUP 2 (SDG2) has been shown to be necessary for global genome-wide H3K4me3 deposition. Although pleiotropic phenotypes have been uncovered in the sdg2 mutants, SDG2 function in the regulation of stem cell ...

  2. CrN films deposited by ion source-assisted magnetron sputtering

    International Nuclear Information System (INIS)

    CrN coatings were deposited on Si (100) and piston rings by ion source assisted 40 kHz magnetron sputtering. Structure and composition of the coatings were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. Mechanical and tribological properties were assessed by microhardness and pin-on-disc testing. The ion source-assisted system has a deposition rate of 3.88 μm/h, against 2.2 μm/h without ion-source assistance. The CrN coatings prepared with ion source assistance exhibited an increase in microhardness (up to 16.3 GPa) and decrease in friction coefficient (down to 0.48) at the optimized cathode source-to-substrate distance. Under optimized conditions, CrN coatings were deposited on piston rings, with a thickness of 25 μm and hardness of 17.85 GPa. (authors)

  3. Microstructure and wear behaviour of silicon doped Cr-N nanocomposite coatings

    International Nuclear Information System (INIS)

    Hard Cr-N and silicon doped Cr-Si-N nanocomposite coatings were deposited using closed unbalanced magnetron sputtering ion plating system. Coatings doped with various Si contents were synthesized by changing the power applied on Si targets. Composition of the films was analyzed using glow discharge optical emission spectrometry (GDOES). Microstructure and properties of the coatings were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and nano-indentation. The harnesses and the elastic modulus of Cr-Si-N coatings gradually increased with rising of silicon content and exhibited a maximum at silicon content of 4.1 at.% and 5.5 at.%. The maximum hardness and elastic modulus of the Cr-Si-N nanocomposite coatings were approximately 30 GPa and 352 GPa, respectively. Further increase in the silicon content resulted in a decrease in the hardness and the elastic modulus of the coatings. Results from XRD analyses of CrN coatings indicated that strongly preferred orientations of (111) were detected. The diffraction patterns of Cr-Si-N coatings showed a clear (220) with weak (200) and (311) preferred orientations, but the peak of CrN (111) was decreased with the increase of Si concentration. The XRD data of single-phase Si3N4 was free of peak. The peaks of CrN (111) and (220) were shifted slightly and broadened with the increase of silicon content. SEM observations of the sections of Cr-Si-N coatings with different silicon concentrations showed a typical columnar structure. It was evident from TEM observation that nanocomposite Cr-Si-N coatings exhibited nano-scale grain size. Friction coefficient and specific wear rate (SWR) of silicon doped Cr-N coatings from pin-on-disk test were significantly lower in comparison to that of CrN coatings.

  4. The properties and wear resistance of the CrN PVD coatings

    Directory of Open Access Journals (Sweden)

    M. Polok-Rubiniec

    2008-10-01

    Full Text Available Purpose: The aim of the paper is comparison of the mechanical properties and wear resistance of the monolayer CrN PVD coatings deposited onto heat treated and plasma nitrited X37CrMoV5-1 type hot work tool steel.Design/methodology/approach: The microhardness tests of the PVD coatings were made on the dynamic ultra-microhardness tester. The surfaces’ thopography and the structure of the PVD coatings was observed on the scanning electron microscopy. The evaluation of the adhesion of coatings to the substrate was made using the scratch test. The wear and friction tests were performed on a pin-on-disc device at the room temperature and at the temperature of 500°C. The friction coefficient between the ball and disc was measured during the test.Findings: : In case of the CrN coating deposited onto the X37CrMoV5-1 nitrided hot work steel a very good adhesion has been revealed to the substrate material in comparison to the CrN coating deposited onto the heat treated hot work steel. Taking into account the results of measurements, one can state that the lowest wear at certain conditions at both room and elevated temperatures displays the CrN coating deposited onto plasma nitrited X37CrMo V5-1 hot work steel type.Practical implications: The investigation results will provide useful information to applying the plasma nitriding and the CrN PVD coatings for the improvement of the wear resistance of tools made from hot work steels.Originality/value: The paper contributes to better understanding of the structure, mechanical properties, adhesion and the wear resistance at the elevated temperature (500°C of the monolayer CrN PVD coating deposited onto the heat treated and plasma nitrited hot work tool steel.

  5. Nanoindentation study of magnetron-sputtered CrN and CrSiN coatings

    International Nuclear Information System (INIS)

    Research highlights: → Mechanical properties of CrN and CrSiN coatings were investigated by using nanoindentation technique. → The CrN coatings showed maximum hardness (H) and modulus (E) of 21 ± 0.85 GPa and 276 ± 13 GPa, respectively. → The improved hardness of the coatings was due to the reduction in crystallite size, decrease in surface roughness, and dense morphology. -- Abstract: CrN and CrSiN coatings were deposited on stainless steel substrate by reactive magnetron sputtering. The coatings were characterized for phases, chemical composition, microstructure, and mechanical properties by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM)/energy dispersive spectroscopy (EDS), atomic force microscopy (AFM), and nanoindentation technique, respectively. The cubic phase was the only phase observed in both the coatings as observed in XRD results. A dense morphology was observed in these coatings deposited with high nitrogen and Si contents, 50:50 and 18.65 at.%, respectively. Nanoindentation measurement of CrN coatings, with Ar + N2 proportions of 60:40, showed maximum hardness (H) and modulus (E) of 21 ± 0.85 GPa and 276 ± 13 GPa, respectively. The CrN coatings deposited in pure N2 atmosphere showed H and E values of 27 ± 1.62 and 241 ± 10 GPa, respectively. The measured H and E values of CrSiN coatings were found to be 28 ± 1.40 GPa and 246 ± 10 GPa, respectively. The improved hardness in both the coatings was attributed mainly to a reduction in crystallite size, decrease in surface roughness, and dense morphology. The incorporation of Si into the CrN coatings has improved both hardness and Young's modulus.

  6. Characterization of the arc ion-plated CrN coatings oxidized at elevated temperatures

    International Nuclear Information System (INIS)

    Microstructure and chemistry of the arc ion-plated CrN coatings oxidized in air at temperatures ranging from 300 to 800 deg. C for 60 min were analyzed by x-ray diffraction (XRD), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), and Auger electron spectroscopy (AES). The CrN coatings were prepared by cathodic arc ion plating deposition on a type 304 stainless steel with a Cr interlayer. The XRD result shows that oxidation of the CrN-coated steel above 500 deg. C produces two new phases, Cr2O3 and β-Cr2N, and the amount of both phases increases with the oxidation temperature. Cross-section TEM shows three distinct regions including the steel substrate, the Cr interlayer, and the CrN coating in the as-deposited specimen, in which the CrN layer exhibits a columnar structure and preferred orientation. Oxidation of the CrN-coated steel at high temperatures produces an oxide layer, Cr2O3, on the coating surface, and the underlayer is a mixture of CrN and β-Cr2N phases. Unlike the as-deposited specimen, the dual phase layer in the oxidized specimens has an equiaxed grain structure and the average grain size of the layer increases with the oxidation temperature. In addition, pronounced grain growth in the dual phase layer near the coating surface is observed in the specimen heat-treated at 800 deg. C. Elemental analyses of the CrN coating near the free surface by EELS and AES reveal that the O/N ratio of the coating and the thickness of the oxide layer increase with the oxidation temperature

  7. Tribological property enhancement of CrN films by metal vapor vacuum arc implantation of Vanadium and Carbon ions

    International Nuclear Information System (INIS)

    CrN films have been extensively used in precision forming and molding applications because of their excellent tribological properties and oxidation-resisting characteristics. Vanadium and carbon ions are introduced into the near surface layer of deposited CrN films via metal vapor vacuum arc implantation to improve the wear performance of CrN films. Dense and smooth CrN film was deposited using a filtered arc deposition system, which provides fully ionized Cr plasma on the substrate surface. Subsequently, surface bombardment of the deposited CrN film with vanadium and carbon ions densifies the film and forms an alloy near the surface. These CrN-based films were characterized by X-ray photoelectron electron and Auger electron spectroscopies. Examinations of the tribological and mechanical film properties, including wear resistance, corrosion resistance and fracture toughness were performed and correlated with respect to the implantation parameters

  8. The novel protein DELAYED PALE-GREENING1 is required for early chloroplast biogenesis in Arabidopsis thaliana.

    Science.gov (United States)

    Liu, Dong; Li, Weichun; Cheng, Jianfeng

    2016-01-01

    Chloroplast biogenesis is one of the most important subjects in plant biology. In this study, an Arabidopsis early chloroplast biogenesis mutant with a delayed pale-greening phenotype (dpg1) was isolated from a T-DNA insertion mutant collection. Both cotyledons and true leaves of dpg1 mutants were initially albino but gradually became pale green as the plant matured. Transmission electron microscopic observations revealed that the mutant displayed a delayed proplastid-to-chloroplast transition. Sequence and transcription analyses showed that AtDPG1 encodes a putatively chloroplast-localized protein containing three predicted transmembrane helices and that its expression depends on both light and developmental status. GUS staining for AtDPG1::GUS transgenic lines showed that this gene was widely expressed throughout the plant and that higher expression levels were predominantly found in green tissues during the early stages of Arabidopsis seedling development. Furthermore, quantitative real-time RT-PCR analyses revealed that a number of chloroplast- and nuclear-encoded genes involved in chlorophyll biosynthesis, photosynthesis and chloroplast development were substantially down-regulated in the dpg1 mutant. These data indicate that AtDPG1 plays an essential role in early chloroplast biogenesis, and its absence triggers chloroplast-to-nucleus retrograde signalling, which ultimately down-regulates the expression of nuclear genes encoding chloroplast-localized proteins. PMID:27160321

  9. Nucleolin is required for DNA methylation state and the expression of rRNA gene variants in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Frédéric Pontvianne

    2010-11-01

    Full Text Available In eukaryotes, 45S rRNA genes are arranged in tandem arrays in copy numbers ranging from several hundred to several thousand in plants. Although it is clear that not all copies are transcribed under normal growth conditions, the molecular basis controlling the expression of specific sets of rRNA genes remains unclear. Here, we report four major rRNA gene variants in Arabidopsis thaliana. Interestingly, while transcription of one of these rRNA variants is induced, the others are either repressed or remain unaltered in A. thaliana plants with a disrupted nucleolin-like protein gene (Atnuc-L1. Remarkably, the most highly represented rRNA gene variant, which is inactive in WT plants, is reactivated in Atnuc-L1 mutants. We show that accumulated pre-rRNAs originate from RNA Pol I transcription and are processed accurately. Moreover, we show that disruption of the AtNUC-L1 gene induces loss of symmetrical DNA methylation without affecting histone epigenetic marks at rRNA genes. Collectively, these data reveal a novel mechanism for rRNA gene transcriptional regulation in which the nucleolin protein plays a major role in controlling active and repressed rRNA gene variants in Arabidopsis.

  10. Neutron diffraction verification of strong Cr-N interaction in nitrogen steels

    International Nuclear Information System (INIS)

    The existence of a strong chemical bond Cr-N in nitrogen-bearing austenite is shown using the neutron diffraction method. Compared to (Mn, Fe)-N and (Cr, Mn, Fe, Ni)-C chemical bonds a Cr-N bond is 30 % stronger and its potential pit depth is twice as high. Because of this strong bond nitrogen is captured by chromium clusters inside of efficient retardation of dislocations and a decrease of nitrogen austenite stability. The strong Cr-Ni bond is an explanation of the advantages of nitrogen steels over carbon ones

  11. TOM1, an Arabidopsis gene required for efficient multiplication of a tobamovirus, encodes a putative transmembrane protein.

    Science.gov (United States)

    Yamanaka, T; Ohta, T; Takahashi, M; Meshi, T; Schmidt, R; Dean, C; Naito, S; Ishikawa, M

    2000-08-29

    Host-encoded factors play an important role in virus multiplication, acting in concert with virus-encoded factors. However, information regarding the host factors involved in this process is limited. Here we report the map-based cloning of an Arabidopsis thaliana gene, TOM1, which is necessary for the efficient multiplication of tobamoviruses, positive-strand RNA viruses infecting a wide variety of plants. The TOM1 mRNA is suggested to encode a 291-aa polypeptide that is predicted to be a multipass transmembrane protein. The Sos recruitment assay supported the hypothesis that TOM1 is associated with membranes, and in addition, that TOM1 interacts with the helicase domain of tobamovirus-encoded replication proteins. Taken into account that the tobamovirus replication complex is associated with membranes, we propose that TOM1 participates in the in vivo formation of the replication complex by serving as a membrane anchor. PMID:10944200

  12. Phosphorylation of CRN2 by CK2 regulates F-actin and Arp2/3 interaction and inhibits cell migration

    OpenAIRE

    Xavier, Charles Peter; Rastetter, Raphael H.; Bloemacher, Margit; Morgan Beesly, Reginald Owen; Fernández Fernández, María Pilar; Wang, Conan; Osman, Asiah; Miyata, Yoshihiko; (et al.)

    2012-01-01

    CRN2 (synonyms: coronin 1C, coronin 3) functions in the re-organization of the actin network and is implicated in cellular processes like protrusion formation, secretion, migration and invasion. We demonstrate that CRN2 is a binding partner and substrate of protein kinase CK2, which phosphorylates CRN2 at S463 in its C-terminal coiled coil domain. Phosphomimetic S463D CRN2 loses the wild-type CRN2 ability to inhibit actin polymerization, to bundle F-actin, and to bind to the Arp2/3 complex. A...

  13. Controlling the structural transition at the Néel point of CrN epitaxial thin films using epitaxial growth

    OpenAIRE

    Inumaru, Kei; Koyama, Kunihiko; Imo-oka, Naoya; Yamanaka, Shoji

    2007-01-01

    Chromium nitride (CrN) films were epitaxially grown on α- Al2 O3 (0001) and MgO (001) substrates by pulsed laser deposition at 973 K under nitrogen radical irradiation, and the structural change of the films was investigated at around the Néel temperature of CrN (∼270 K) by temperature-controlled x-ray diffraction experiments. Bulk cubic CrN is known to show monoclinic distortion below the Néel temperature. The CrN film grown on MgO(001) with the CrN(001) plane parallel to the substrate sur...

  14. An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination.

    Directory of Open Access Journals (Sweden)

    Julien De Giorgi

    2015-12-01

    Full Text Available Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA and abscisic acid (ABA signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties.

  15. Arabidopsis VARIEGATED 3 encodes a chloroplast-targeted, zinc-finger protein required for chloroplast and palisade cell development

    DEFF Research Database (Denmark)

    Næsted, Henrik; Holm, Agnethe; Jenkins, Tom; Nielsen, Henrik Bjørn; Harris, Cassandra A.; Beale, Michael H.; Andersen, Mathias; Mant, Alexandra; Scheller, Henrik Vibe; Camara, Bilal; Mattsson, Ole; Mundy, John

    2004-01-01

    The stable, recessive Arabidopsis variegated 3 (var3) mutant exhibits a variegated phenotype due to somatic areas lacking or containing developmentally retarded chloroplasts and greatly reduced numbers of palisade cells. The VAR3 gene, isolated by transposon tagging, encodes the 85.9 kDa VAR3 pro...... pigment profiles are qualitatively similar in wild type and var3, although var3 accumulates lower levels of chlorophylls and carotenoids. These results indicate that VAR3 is a part of a protein complex required for normal chloroplast and palisade cell development....... protein containing novel repeats and zinc fingers described as protein interaction domains. VAR3 interacts specifically in yeast and in vitro with NCED4, a putative polyene chain or carotenoid dioxygenase, and both VAR3 and NCED4 accumulate in the chloroplast stroma. Metabolic profiling demonstrates that...

  16. The HopQ1 effector's nucleoside hydrolase-like domain is required for bacterial virulence in arabidopsis and tomato, but not host recognition in tobacco.

    Directory of Open Access Journals (Sweden)

    Wei Li

    Full Text Available Bacterial pathogens deliver multiple effector proteins into host cells to facilitate bacterial growth. HopQ1 is an effector from Pseudomonas syringae pv. tomato DC3000 that is conserved across multiple bacterial pathogens which infect plants. HopQ1's central region possesses some homology to nucleoside hydrolases, but possesses an alternative aspartate motif not found in characterized enzymes. A structural model was generated for HopQ1 based on the E. coli RihB nucleoside hydrolase and the role of HopQ1's potential catalytic residues for promoting bacterial virulence and recognition in Nicotiana tabacum was investigated. Transgenic Arabidopsis plants expressing HopQ1 exhibit enhanced disease susceptibility to DC3000. HopQ1 can also promote bacterial virulence on tomato when naturally delivered from DC3000. HopQ1's nucleoside hydrolase-like domain alone is sufficient to promote bacterial virulence, and putative catalytic residues are required for virulence promotion during bacterial infection of tomato and in transgenic Arabidopsis lines. HopQ1 is recognized and elicits cell death when transiently expressed in N. tabacum. Residues required to promote bacterial virulence were dispensable for HopQ1's cell death promoting activities in N. tabacum. Although HopQ1 has some homology to nucleoside hydrolases, we were unable to detect HopQ1 enzymatic activity or nucleoside binding capability using standard substrates. Thus, it is likely that HopQ1 promotes pathogen virulence by hydrolyzing alternative ribose-containing substrates in planta.

  17. Corrosion resistance of CrN thin films produced by dc magnetron sputtering

    International Nuclear Information System (INIS)

    In this study, the electrochemical behavior of chromium nitride (CrN) coatings deposited on two steel substrates, AISI 304 and AISI 1440, was investigated. The CrN coatings were prepared using a reactive d.c. magnetron sputtering deposition technique at two different pressures (P1 = 0.4 Pa and P2 = 4 Pa) with a mixture of N2–Ar (1.5-10). The microstructure and crystallinity of the CrN coatings were investigated using X-ray diffraction. The aqueous corrosion behavior of the coatings was evaluated using two methods. The polarization resistance (Tafel curves) and electrochemical impedance spectra (EIS) in a saline (3.5% NaCl solution) environment were measured in terms of the open-circuit potentials and polarization resistance (Rp). The results indicated that the CrN coatings present better corrosion resistance and Rp values than do the uncoated steel substrates, especially for the coatings produced on the AISI 304 substrates, which exhibited a strong enhancement in the corrosion resistance. Furthermore, better behavior was observed for the coatings produced at lower pressures (0.4 Pa) than those grown at 4 Pa.

  18. Ion-beam irradiation effects on reactively sputtered CrN thin films

    International Nuclear Information System (INIS)

    The present study deals with CrN/Si bilayers irradiated at room temperature (RT) with 120 keV Ar ions. The CrN layers were deposited by d.c. reactive sputtering on Si(1 0 0) wafers, at different nitrogen partial pressures (2 x 10-4, 3.5 x 10-4 and 5 x 10-4 mbar), to a total thickness of 240-280 nm. The substrates were held at room temperature (RT) or 150 oC during deposition. After deposition the CrN/Si bilayers were irradiated up to fluences of 1 x 1015 and 1 x 1016 ions/cm2. Structural characterization was performed with Rutherford backscattering spectroscopy (RBS), cross-sectional transmission electron microscopy (XTEM) and grazing angle X-ray diffraction (XRD). For the highest nitrogen pressure (5 x 10-4 mbar) a pure stoichiometric CrN phase was achieved. The results showed that Ar ion irradiation resulted in the variation of the lattice constants, micro-strain and mean grain size of the CrN layers. The observed microstructural changes are due to the formation of the high density damage region in the CrN thin film structure.

  19. The electrochemical behavior of thermally oxidized CrN coatings deposited on steel by cathodic arc plasma deposition

    International Nuclear Information System (INIS)

    Cathodic arc plasma deposition of the CrN coating has been applied to an industrial scale to improve the corrosion resistance of the AISI 304 stainless steel. Thermal oxidation in air was carried out at the temperature of 500 and 800 deg. C for 1 h. The effect of the thermal oxidation on the aqueous corrosion behavior of the CrN/304s assembly was investigated in this study. The composition and structure of the CrN coatings were studied by the grazing X-ray diffraction (GXRD), electron probe X-ray microanalyzer (EPMA), and X-ray photoelectron spectroscopy (XPS). The polarization resistance (Rp) of all samples was measured and compared in terms of a polarization resistance resulting from electrochemical impedance spectroscopy (EIS) in a mixture of 0.5 M H2SO4 + 1 M NaCl solution. The results indicated that the corrosion resistance of the CrN coated steel oxidized at 500 deg. C is significantly reduced. On the contrary, the electrochemical behavior of the CrN coated steel oxidized at 800 deg. C shows better corrosion resistance than the one oxidized at 500 deg. C and as-deposited steel. After thermal oxidation at 800 deg. C, the oxide layer formed on top of CrN coating enhances the corrosion protection of the CrN coated steel

  20. Cloning, overexpression, purification and crystallization of the CRN12 coiled-coil domain from Leishmania donovani

    International Nuclear Information System (INIS)

    The L. donovani coronin CRN12 coiled-coil domain (5.8 kDa) was cloned, overexpressed and purified to homogeneity. Crystals of recombinant L. donovani coronin CRN12 coiled-coil domain were grown by vapour diffusion using a hanging-drop setup. Leishmania donovani coronin CRN12 is an actin-binding protein which consists of two domains: an N-terminal WD repeat domain and a C-terminal coiled-coil domain. The coiled-coil domain is 53 residues in length. Helix–helix interactions in general and coiled coils in particular are ubiquitous in the structure of proteins and play a significant role in the association among proteins, including supramolecular assemblies and transmembrane receptors that mediate cellular signalling, transport and actin dynamics. The L. donovani coronin CRN12 coiled-coil domain (5.8 kDa) was cloned, overexpressed, purified to homogeneity and the N-terminal 6×His tag was successfully removed by thrombin cleavage. Crystals of recombinant L. donovani coronin CRN12 coiled-coil domain were grown by vapour diffusion using a hanging-drop setup. Diffraction-quality crystals were obtained and data extending to 2.46 Å resolution were collected at 100 K on BM14, ESRF, Grenoble, France. The crystal belonged to the monoclinic space group C2, with unit-cell parameters a = 118.0, b = 50.6, c = 46.0 Å, β = 111.0°. Matthews coefficient (VM) calculations suggested the presence of 4–6 molecules in the asymmetric unit, corresponding to a solvent content of ∼33–55%, and are consistent with self-rotation function calculations

  1. InN nanorods prepared with CrN nanoislands by plasma-assisted molecular beam epitaxy

    OpenAIRE

    Young Sheng-Joue; Wu Ya-Ling; Chen Yue-Zhang; Hung Hung; Wang Shih-Ming; Chen Kuan-Jen; Liu Kuang-Wei; Chang Shoou-Jinn; Hsueh Tao-Hung; Mai Yu-Chun

    2011-01-01

    Abstract The authors report the influence of CrN nanoisland inserted on growth of baseball-bat InN nanorods by plasma-assisted molecular beam epitaxy under In-rich conditions. By inserting CrN nanoislands between AlN nucleation layer and the Si (111) substrate, it was found that we could reduce strain form Si by inserting CrN nanoisland, FWHM of the x-ray rocking curve measured from InN nanorods from 3,299 reduced to 2,115 arcsec. It is due to the larger strain from lattice miss-match of the ...

  2. The MTL1 Pentatricopeptide Repeat Protein Is Required for Both Translation and Splicing of the Mitochondrial NADH DEHYDROGENASE SUBUNIT7 mRNA in Arabidopsis.

    Science.gov (United States)

    Haïli, Nawel; Planchard, Noelya; Arnal, Nadège; Quadrado, Martine; Vrielynck, Nathalie; Dahan, Jennifer; des Francs-Small, Catherine Colas; Mireau, Hakim

    2016-01-01

    Mitochondrial translation involves a complex interplay of ancient bacteria-like features and host-derived functionalities. Although the basic components of the mitochondrial translation apparatus have been recognized, very few protein factors aiding in recruiting ribosomes on mitochondria-encoded messenger RNA (mRNAs) have been identified in higher plants. In this study, we describe the identification of the Arabidopsis (Arabidopsis thaliana) MITOCHONDRIAL TRANSLATION FACTOR1 (MTL1) protein, a new member of the Pentatricopeptide Repeat family, and show that it is essential for the translation of the mitochondrial NADH dehydrogenase subunit7 (nad7) mRNA. We demonstrate that mtl1 mutant plants fail to accumulate the Nad7 protein, even though the nad7 mature mRNA is produced and bears the same 5' and 3' extremities as in wild-type plants. We next observed that polysome association of nad7 mature mRNA is specifically disrupted in mtl1 mutants, indicating that the absence of Nad7 results from a lack of translation of nad7 mRNA. These findings illustrate that mitochondrial translation requires the intervention of gene-specific nucleus-encoded PPR trans-factors and that their action does not necessarily involve the 5' processing of their target mRNA, as observed previously. Interestingly, a partial decrease in nad7 intron 2 splicing was also detected in mtl1 mutants, suggesting that MTL1 is also involved in group II intron splicing. However, this second function appears to be less essential for nad7 expression than its role in translation. MTL1 will be instrumental to understand the multifunctionality of PPR proteins and the mechanisms governing mRNA translation and intron splicing in plant mitochondria. PMID:26537562

  3. Arabidopsis Raf-Like Mitogen-Activated Protein Kinase Kinase Kinase Gene Raf43 Is Required for Tolerance to Multiple Abiotic Stresses.

    Directory of Open Access Journals (Sweden)

    Nasar Virk

    Full Text Available Mitogen-activated protein kinase (MAPK cascades are critical signaling modules that mediate the transduction of extracellular stimuli into intracellular response. A relatively large number of MAPKKKs have been identified in a variety of plant genomes but only a few of them have been studied for their biological function. In the present study, we identified an Arabidopsis Raf-like MAPKKK gene Raf43 and studied its function in biotic and abiotic stress response using a T-DNA insertion mutant raf43-1 and two Raf43-overexpressing lines Raf43-OE#1 and Raf43-OE#13. Expression of Raf43 was induced by multiple abiotic and biotic stresses including treatments with drought, mannitol and oxidative stress or defense signaling molecule salicylic acid and infection with necrotrophic fungal pathogen Botrytis cinerea. Seed germination and seedling root growth of raf43-1 were significantly inhibited on MS medium containing mannitol, NaCl, H2O2 or methyl viologen (MV while seed germination and seedling root growth of the Raf43-OE#1 and Raf43-OE#13 lines was similar to wild type Col-0 under the above stress conditions. Soil-grown raf43-1 plants exhibited reduced tolerance to MV, drought and salt stress. Abscisic acid inhibited significantly seed germination and seedling root growth of the raf43-1 line but had no effect on the two Raf43-overexpressing lines. Expression of stress-responsive RD17 and DREB2A genes was significantly down-regulated in raf43-1 plants. However, the raf43-1 and Raf43-overexpressing plants showed similar disease phenotype to the wild type plants after infection with B. cinerea or Pseudomonas syringae pv. tomato DC3000. Our results demonstrate that Raf43, encoding for a Raf-like MAPKKK, is required for tolerance to multiple abiotic stresses in Arabidopsis.

  4. Ethylene signaling is required for the acceleration of cell death induced by the activation of At ME K5 in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Hongxia Liu; Ying Wang; Juan Xu; Tongbing Su; Guoqin Liu; Dongtao Ren

    2008-01-01

    Mitogen-activated protein kinases (MAPKs) are involved in the regulation of plant growth, development and responses to a wide variety of stimuli. In a conditional gain-of-function transgenic system, the activation of AtM£K5, a MAPK kinase, can in turn activate endogenous AtMAPK3 and AtMAPK6, and can lead to a striking increase in ethylene production and induce hypersensitive response (HR)-like cell death in Arabidopsis. However, the role of the increased ethylene production in regulating this HR-like cell death remains unknown. Using Arabidopsis transgenic plants that express AtMEK5DD , an active mutant of AtMEK5 that is under the control of a steroid-inducible promoter, we tested the contribution of ethylene to cell death. We found that ethylene biosynthesis occurs before cell death. Cell death was delayed by inhibiting AtMEK5-induced ethylene production using inhibitors of ACC-synthases, ACC-oxidases or ethylene receptors. In the mutants AtMEK5DDletrl-1 and AtMEK5DDlein2-l, both of which showed insen-sitivity to ethylene, the expression of AtMEKSDD protein, activity of AtMAPK3 and AtMAPK6, and ethylene production were the same as those seen in AtMEK.5 transgenic plants, but cell death was also delayed. These data suggest that ethylene signaling perception is required to accelerate cell death that is induced by AtMEK5 activation.

  5. Riboflavin-Induced Disease Resistance Requires the Mitogen-Activated Protein Kinases 3 and 6 in Arabidopsis thaliana

    Science.gov (United States)

    Nie, Shengjun; Xu, Huilian

    2016-01-01

    As a resistance elicitor, riboflavin (vitamin B2) protects plants against a wide range of pathogens. At molecular biological levels, it is important to elucidate the signaling pathways underlying the disease resistance induced by riboflavin. Here, riboflavin was tested to induce resistance against virulent Pseudomonas syringae pv. Tomato DC3000 (Pst DC3000) in Arabidopsis. Results showed that riboflavin induced disease resistance based on MAPK-dependent priming for the expression of PR1 gene. Riboflavin induced transient expression of PR1 gene. However, following Pst DC3000 inoculation, riboflavin potentiated stronger PR1 gene transcription. Further was suggested that the transcript levels of mitogen-activated protein kinases, MPK3 and MPK6, were primed under riboflavin. Upon infection by Pst DC3000, these two enzymes were more strongly activated. The elevated activation of both MPK3 and MPK6 was responsible for enhanced defense gene expression and resistance after riboflavin treatment. Moreover, riboflavin significantly reduced the transcript levels of MPK3 and MPK6 by application of AsA and BAPTA, an H2O2 scavenger and a calcium (Ca2+) scavenger, respectively. In conclusion, MPK3 and MPK6 were responsible for riboflavin-induced resistance, and played an important role in H2O2- and Ca2+-related signaling pathways, and this study could provide a new insight into the mechanistic study of riboflavin-induced defense responses. PMID:27054585

  6. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Wang, Zhenyu

    2011-05-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

  7. BURSTING POLLEN is required to organize the pollen germination plaque and pollen tube tip in Arabidopsis thaliana.

    Science.gov (United States)

    Hoedemaekers, Karin; Derksen, Jan; Hoogstrate, Suzanne W; Wolters-Arts, Mieke; Oh, Sung-Aeong; Twell, David; Mariani, Celestina; Rieu, Ivo

    2015-04-01

    Pollen germination may occur via the so-called germination pores or directly through the pollen wall at the site of contact with the stigma. In this study, we addressed what processes take place during pollen hydration (i.e. before tube emergence), in a species with extra-poral pollen germination, Arabidopsis thaliana. A T-DNA mutant population was screened by segregation distortion analysis. Histological and electron microscopy techniques were applied to examine the wild-type and mutant phenotypes. Within 1 h of the start of pollen hydration, an intine-like structure consisting of cellulose, callose and at least partly de-esterified pectin was formed at the pollen wall. Subsequently, this 'germination plaque' gradually extended and opened up to provide passage for the cytoplasm into the emerging pollen tube. BURSTING POLLEN (BUP) was identified as a gene essential for the correct organization of this plaque and the tip of the pollen tube. BUP encodes a novel Golgi-located glycosyltransferase related to the glycosyltransferase 4 (GT4) subfamily which is conserved throughout the plant kingdom. Extra-poral pollen germination involves the development of a germination plaque and BUP defines the correct plastic-elastic properties of this plaque and the pollen tube tip by affecting pectin synthesis or delivery. PMID:25442716

  8. Arabidopsis inositol 1,3,4-trisphosphate 5/6 kinase 2 is required for seed coat development

    Institute of Scientific and Technical Information of China (English)

    Yong Tang; Shutang Tan; Hongwei Xue

    2013-01-01

    Inositol 1,3,4-trisphosphate 5/6 kinase (ITPK) phosphorylates inositol 1,3,4-trisphosphate to form inositol 1,3,4,5-tetrakisphosphate and inositol 1,3,4,6-tetrakisphosphate which can be finally transferred to inositoi hexaphosphate (IP6) and play important roles during plant growth and development.There are 4 putative ITPK members in Arabidopsis.Expression pattern analysis showed that ITPK2 is constitutively expressed in various tissues.A TDNA knockout mutant of ITPK2 was identified and scanning electron microscopy (SEM) analysis showed that the epidermis structure of seed coat was irregularly formed in seeds of itpk2-1 mutant,resulting in the increased permeability of seed coat to tetrazolium salts.Further analysis by gas chromatography coupled with mass spectrometry of lipid polyester monomers in cell wall confirmed a dramatic decrease in composition of suberin and cutin,which relate to the permeability of seed coat and the formation of which is accompanied with seed coat development.These results indicate that ITPK2 plays an essential role in seed coat development and lipid polyester barrier formation.

  9. YUCCA-mediated auxin biogenesis is required for cell fate transition occurring during de novo root organogenesis in Arabidopsis.

    Science.gov (United States)

    Chen, Lyuqin; Tong, Jianhua; Xiao, Langtao; Ruan, Ying; Liu, Jingchun; Zeng, Minhuan; Huang, Hai; Wang, Jia-Wei; Xu, Lin

    2016-07-01

    Many plant organs have the ability to regenerate a new plant after detachment or wounding via de novo organogenesis. During de novo root organogenesis from Arabidopsis thaliana leaf explants, endogenic auxin is essential for the fate transition of regeneration-competent cells to become root founder cells via activation of WUSCHEL-RELATED HOMEOBOX 11 (WOX11). However, the molecular events from leaf explant detachment to auxin-mediated cell fate transition are poorly understood. In this study, we used an assay to determine the concentration of indole-3-acetic acid (IAA) to provide direct evidence that auxin is produced after leaf explant detachment, a process that involves YUCCA (YUC)-mediated auxin biogenesis. Inhibition of YUC prevents expression of WOX11 and fate transition of competent cells, resulting in the blocking of rooting. Further analysis showed that YUC1 and YUC4 act quickly (within 4 hours) in response to wounding after detachment in both light and dark conditions and promote auxin biogenesis in both mesophyll and competent cells, whereas YUC5, YUC8, and YUC9 primarily respond in dark conditions. In addition, YUC2 and YUC6 contribute to rooting by providing a basal auxin level in the leaf. Overall, our study indicates that YUC genes exhibit a division of labour during de novo root organogenesis from leaf explants in response to multiple signals. PMID:27255928

  10. Arabidopsis PROTEASOME REGULATOR1 is required for auxin-mediated suppression of proteasome activity and regulates auxin signalling.

    Science.gov (United States)

    Yang, Bao-Jun; Han, Xin-Xin; Yin, Lin-Lin; Xing, Mei-Qing; Xu, Zhi-Hong; Xue, Hong-Wei

    2016-01-01

    The plant hormone auxin is perceived by the nuclear F-box protein TIR1 receptor family and regulates gene expression through degradation of Aux/IAA transcriptional repressors. Several studies have revealed the importance of the proteasome in auxin signalling, but details on how the proteolytic machinery is regulated and how this relates to degradation of Aux/IAA proteins remains unclear. Here we show that an Arabidopsis homologue of the proteasome inhibitor PI31, which we name PROTEASOME REGULATOR1 (PTRE1), is a positive regulator of the 26S proteasome. Loss-of-function ptre1 mutants are insensitive to auxin-mediated suppression of proteasome activity, show diminished auxin-induced degradation of Aux/IAA proteins and display auxin-related phenotypes. We found that auxin alters the subcellular localization of PTRE1, suggesting this may be part of the mechanism by which it reduces proteasome activity. Based on these results, we propose that auxin regulates proteasome activity via PTRE1 to fine-tune the homoeostasis of Aux/IAA repressor proteins thus modifying auxin activity. PMID:27109828

  11. Nuclear activity of ROXY1, a glutaredoxin interacting with TGA factors, is required for petal development in Arabidopsis thaliana.

    Science.gov (United States)

    Li, Shutian; Lauri, Andrea; Ziemann, Mark; Busch, Andrea; Bhave, Mrinal; Zachgo, Sabine

    2009-02-01

    Glutaredoxins (GRXs) have thus far been associated mainly with redox-regulated processes participating in stress responses. However, ROXY1, encoding a GRX, has recently been shown to regulate petal primorida initiation and further petal morphogenesis in Arabidopsis thaliana. ROXY1 belongs to a land plant-specific class of GRXs that has a CC-type active site motif, which deviates from ubiquitously occurring CPYC and CGFS GRXs. Expression studies of yellow fluorescent protein-ROXY1 fusion genes driven by the cauliflower mosaic virus 35S promoter reveal a nucleocytoplasmic distribution of ROXY1. We demonstrate that nuclear localization of ROXY1 is indispensable and thus crucial for its activity in flower development. Yeast two-hybrid screens identified TGA transcription factors as interacting proteins, which was confirmed by bimolecular fluorescence complementation experiments showing their nuclear interaction in planta. Overlapping expression patterns of ROXY1 and TGA genes during flower development demonstrate that ROXY1/TGA protein interactions can occur in vivo and support their biological relevance in petal development. Deletion analysis of ROXY1 demonstrates the importance of the C terminus for its functionality and for mediating ROXY1/TGA protein interactions. Phenotypic analysis of the roxy1-2 pan double mutant and an engineered chimeric repressor mutant from PERIANTHIA (PAN), a floral TGA gene, supports a dual role of ROXY1 in petal development. Together, our results show that the ROXY1 protein functions in the nucleus, likely by modifying PAN posttranslationally and thereby regulating its activity in petal primordia initiation. Additionally, ROXY1 affects later petal morphogenesis, probably by modulating other TGA factors that might act redundantly during differentiation of second whorl organs. PMID:19218396

  12. Synthesis of nanocrystalline CrN from Cr[OC(NH2)2]6Cl3 coordination compound

    International Nuclear Information System (INIS)

    Nanocrystalline chromium nitride (CrN) particles were prepared by the pyrolysis of Cr[OC(NH2)2]6Cl3 coordination compound in ammonia gas. The compound was characterized by infrared spectrum analysis and thermogravimetry-differential scanning calorimetry (TG-DSC). X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to investigate the phase and morphology of the CrN powders. The CrN particle size obtained at 600 deg. C was as small as 7 nm. The influence of reaction temperature and time on particle sizes was also studied. The formation of CrN nanoparticles was proposed following nucleation and growth mechanism on the basis of the experimental results

  13. Structure and Mechanical Properties of CrN Thick Films Deposited by High-Rate Medium-Frequency Magnetron Sputtering

    International Nuclear Information System (INIS)

    A home-made electron source assisted medium-frequency (MF) magnetron sputtering system was used to deposit thick CrN films on silicon and tungsten carbide substrates at various nitrogen flow rates with a fixed total pressure (0.3 Pa) and MF power (11.2 kW). Result from scanning electron microscopy showed that the deposited CrN films have clear columnar structure, and X-ray diffraction revealed a preferred orientation of CrN (200) for samples prepared at a rate of N2/(N2+Ar) below 60%, whereas those prepared at higher N2/(N2+Ar) rate are dominated by Cr2N. Deposition rates up to 12.5 μm/h were achieved and the hardness of the CrN coatings were in a range of 11 GPa to 18 GPa.

  14. The role of N defects in paramagnetic CrN at finite temperatures from first-principles

    OpenAIRE

    Mozafari, Elham; Alling, Björn; Steneteg, Peter; Abrikosov, Igor

    2014-01-01

    Simulations of defects in paramagnetic materials at high temperature constitute a formidable challenge to solid-state theory due to the interaction of magnetic disorder, vibrations, and structural relaxations. CrN is a material where these effects are particularly large due to a strong magnetolattice coupling and a tendency for deviations from the nominal 1: 1 stoichiometry. In this work, we present a first-principles study of nitrogen vacancies and nitrogen interstitials in CrN at elevated t...

  15. CRN-1, a Caenorhabditis elegans FEN-1 homologue, cooperates with CPS-6/EndoG to promote apoptotic DNA degradation

    OpenAIRE

    Parrish, Jay Z.; Yang, Chonglin; Shen, Binghui; Xue, Ding

    2003-01-01

    Oligonucleosomal fragmentation of chromosomes in dying cells is a hallmark of apoptosis. Little is known about how it is executed or what cellular components are involved. We show that crn-1, a Caenorhabditis elegans homologue of human flap endonuclease-1 (FEN-1) that is normally involved in DNA replication and repair, is also important for apoptosis. Reduction of crn-1 activity by RNA interference resulted in cell death phenotypes similar to those displayed by a mutant lacking the mitochondr...

  16. The Unstructured N-terminal Region of Arabidopsis Group 4 Late Embryogenesis Abundant (LEA) Proteins Is Required for Folding and for Chaperone-like Activity under Water Deficit.

    Science.gov (United States)

    Cuevas-Velazquez, Cesar L; Saab-Rincón, Gloria; Reyes, José Luis; Covarrubias, Alejandra A

    2016-05-13

    Late embryogenesis abundant (LEA) proteins are a conserved group of proteins widely distributed in the plant kingdom that participate in the tolerance to water deficit of different plant species. In silico analyses indicate that most LEA proteins are structurally disordered. The structural plasticity of these proteins opens the question of whether water deficit modulates their conformation and whether these possible changes are related to their function. In this work, we characterized the secondary structure of Arabidopsis group 4 LEA proteins. We found that they are disordered in aqueous solution, with high intrinsic potential to fold into α-helix. We demonstrate that complete dehydration is not required for these proteins to sample ordered structures because milder water deficit and macromolecular crowding induce high α-helix levels in vitro, suggesting that prevalent conditions under water deficit modulate their conformation. We also show that the N-terminal region, conserved across all group 4 LEA proteins, is necessary and sufficient for conformational transitions and that their protective function is confined to this region, suggesting that folding into α-helix is required for chaperone-like activity under water limitation. We propose that these proteins can exist as different conformers, favoring functional diversity, a moonlighting property arising from their structural dynamics. PMID:27006402

  17. Transcriptome Analysis of Arabidopsis Wild-Type and g13-sst sim Trichomes Identifies Four Additional Genes Required for Trichome Development

    Institute of Scientific and Technical Information of China (English)

    M.David Marks; Jonathan R Wenger; Edward Gilding; Ross Jilk; Richard A.Dixon

    2009-01-01

    Transcriptome analyses have been performed on mature trichomes isolated from wild-type Arabidopsis leaves and on leaf trichomes isolated from the g13-sst sire double mutant,which exhibit many attributes of immature trichomes.The mature trichome profile contained many highly expressed genes involved in cell wall synthesis,protein turnover,and abiotic stress response.The most highly expressed genes in the g13-sst sim profile encoded ribosomal proteins and other proteins involved in translation.Comparative analyses showed that all but one of the genes encoding transcription factors previously found to be important for trichome formation,and many other trichome-important genes,were preferentially expressed in g13-sstsim trichomes.The analysis of genes preferentially expressed in g13-sstsim led to the identification of four additional genes required for normal trichome development.One of these was the HDG2 gene,which is a member of the HD-ZIP IV transcription factor gene family.Mutations in this gene did not alter trichome expansion,but did alter mature trichome cell walls.Mutations in BLT resulted in a loss of trichome branch formation.The relationship between bit and the phenotypically identical mutant,sti,was explored.Mutations in PEL3,which was previously shown to be required for development of the leaf cuticle,resulted in the occasional tangling of expanding trichomes.Mutations in another gene encoding a protein with an unknown function altered trichome branch formation.

  18. Corrosion and Co elution behavior of CrN coated Co based alloy in high temperature demineralized water

    International Nuclear Information System (INIS)

    Three kinds of experiments were made to evaluate corrosion and Co elution behavior of CrN coated Co based alloy in high temperature demineralized water; (1) long-term corrosion test, (2) Co elution test and (3) critical passive current density (CPCD) measurement of pin-holes in CrN coating. The results of Test (1) indicated that CrN coated Co-alloy specimen produced very little corrosion in simulated BWR primary coolant water up to 2000 h exposure. CrN coating reduced Co elution from Co alloy based rollers and pins to a level ranging from 1/10 to 1/500. Coating thickness and its variety were almost similar among specimens. Thus, the reason of wide variation of the Co elution reducing factor was not clear. CPCD method could be used to determine the pin holes area ratio of CrN coating. Thicker CrN coating had smaller pin holes area ratio. These results showed that Co elution rate of the specimen was closely correlated to pin holes area. (M.N.)

  19. Overexpression of a Phytophthora Cytoplasmic CRN Effector Confers Resistance to Disease, Salinity and Drought in Nicotiana benthamiana.

    Science.gov (United States)

    Rajput, Nasir Ahmed; Zhang, Meixiang; Shen, Danyu; Liu, Tingli; Zhang, Qimeng; Ru, Yanyan; Sun, Peng; Dou, Daolong

    2015-12-01

    The Crinkler (CRN) effector family is produced by oomycete pathogens and may manipulate host physiological and biochemical events inside host cells. Here, PsCRN161 was identified from Phytophthora sojae based on its broad and strong cell death suppression activities. The effector protein contains two predicted nuclear localization signals and localized to nuclei of plant cells, indicating that it may target plant nuclei to modify host cell physiology and function. The chimeric gene GFP:PsCRN161 driven by the Cauliflower mosaic virus (CaMV) 35S promoter was introduced into Nicotiana benthamiana. The four independent PsCRN161-transgenic lines exhibited increased resistance to two oomycete pathogens (P. parasitica and P. capsici) and showed enhanced tolerance to salinity and drought stresses. Digital gene expression profiling analysis showed that defense-related genes, including ABC transporters, Cyt P450 and receptor-like kinases (RLKs), were significantly up-regulated in PsCRN161-transgenic plants compared with GFP (green fluorescent protein) lines, implying that PsCRN161 expression may protect plants from biotic and abiotic stresses by up-regulation of many defense-related genes. The results reveal previously unknown functions of the oomycete effectors, suggesting that the pathogen effectors could be directly used as functional genes for plant molecular breeding for enhancement of tolerance to biotic and abiotic stresses. PMID:26546319

  20. Ion implantation induced structural changes in reactively sputtered Cr-N layers on Si substrates

    International Nuclear Information System (INIS)

    This paper presents a study of the structure and composition of reactively sputtered Cr-N layers as a function of deposition parameters, and the effects of ion implantation on these structures. The layers were deposited on (1 0 0) Si substrates to a thickness of 240-280 nm, at different nitrogen partial pressure, and subsequently irradiated with 120 keV Ar ions. Structural characterisation of the samples was performed with Rutherford backscattering spectroscopy, transmission electron microscopy and X-ray diffraction analysis. We also measured their electrical resistivity with a four point probe. It was found that the layers grow in form of columnar structures, and their composition, Cr2N or CrN, strongly depends on the nitrogen partial pressure during deposition. Ion irradiation induces local micro-structural changes, formation of nano-particles and defects, which can be nicely correlated to the measured electrical resistivity

  1. Effect of magnetic disorder and strong electron correlations on the thermodynamics of CrN

    OpenAIRE

    Alling, Björn; Marten, Tobias; Abrikosov, Igor

    2010-01-01

    We use first-principles calculations to study the effect of magnetic disorder and electron correlations on the structural and thermodynamic properties of CrN. We illustrate the usability of a special quasirandom structure supercell treatment of the magnetic disorder by comparing with coherent potential approximation calculations and with a complementary magnetic sampling method. The need of a treatment of electron correlations effects beyond the local density approximation is proven by a comp...

  2. Magnetic stress as a driving force of structural distortions: the case of CrN

    OpenAIRE

    Filippetti, Alessio; Hill, Nicola A.

    2000-01-01

    We show that the observed transition from rocksalt to orthorhombic P$_{nma}$ symmetry in CrN can be understood in terms of stress anisotropy. Using local spin density functional theory, we find that the imbalance between stress stored in spin-paired and spin-unpaired Cr nearest neighbors causes the rocksalt structure to be unstable against distortions and justifies the observed antiferromagnetic ordering. This stress has a purely magnetic origin, and may be important in any system where the c...

  3. Structural stability and thermodynamics of CrN magnetic phases from ab initio and experiment

    OpenAIRE

    Zhou, Liangcai; Holec, David; Bartosik, Matthias; Körmann, Fritz; GRABOWSKI, Blazej; Neugebauer, Jörg; Mayrhofer, Paul H.

    2014-01-01

    The dynamical and thermodynamic phase stabilities of the stoichiometric compound CrN including different structural and magnetic configurations are comprehensively investigated using a first-principles density-functional-theory (DFT) plus U approach in conjunction with experimental measurements of the thermal expansion. Comparing DFT and DFT+U results with experimental data reveals that the treatment of electron correlations using methods beyond standard DFT is crucial. The non-magnetic face-...

  4. Loading of Arabidopsis centromeric histone CENH3 occurs mainly during G2 and requires the presence of the histone fold domain

    Czech Academy of Sciences Publication Activity Database

    Lermontova, L.; Schubert, V.; Fuchs, J.; Klatte, J.; Macas, Jiří; Schubert, I.

    2006-01-01

    Roč. 18, - (2006), s. 2443-2451. ISSN 1040-4651 Institutional research plan: CEZ:AV0Z50510513 Keywords : histone CENH3 * Arabidopsis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.868, year: 2006

  5. Role of N defects in paramagnetic CrN at finite temperatures from first principles

    Science.gov (United States)

    Mozafari, E.; Alling, B.; Steneteg, P.; Abrikosov, Igor A.

    2015-03-01

    Simulations of defects in paramagnetic materials at high temperature constitute a formidable challenge to solid-state theory due to the interaction of magnetic disorder, vibrations, and structural relaxations. CrN is a material where these effects are particularly large due to a strong magnetolattice coupling and a tendency for deviations from the nominal 1:1 stoichiometry. In this work, we present a first-principles study of nitrogen vacancies and nitrogen interstitials in CrN at elevated temperature. We report on formation energetics, the geometry of interstitial nitrogen dimers, and the impact on the electronic structure caused by the defects. We find a vacancy formation energy of 2.28 eV with a small effect of temperature, i.e., a formation energy for N interstitial in the form of a -oriented split bond of 3.77 eV with an increase to 3.97 at 1000 K. Vacancies are found to add three electrons, while split-bond interstitial adds one electron to the conduction band. The band gap of defect-free CrN is smeared out due to vibrations, although it is difficult to draw a conclusion about the exact temperature at which the band gap closes from our calculations. However, it is clear that at 900 K there is a nonzero density of electronic states at the Fermi level. At 300 K, our results indicate a border case where the band gap is about to close.

  6. The microstructure and properties of unbalanced magnetron sputtered CrN sub x coatings

    CERN Document Server

    Hurkmans, A P A

    2002-01-01

    The most widely used surface treatment to protect engineering components is the deposition of hard chromium by electroplating. The coatings are known to be quite thick (up to 20 mu m), reasonably hard (approx HV1000), but contain micro-cracks. This wet deposition process is well understood, but it has technical limitations and is under high political pressure because of the environmental pollution by hexavalent chromium. The physical vapour deposition (PVD) technique is an alternative method to produce high quality coatings. PVD is an almost pollution free technique, because the process occurs under vacuum. CrN by PVD is one of the most promising PVD coatings as a candidate to replace eventually electroplated hard chromium. The growth characteristics of CrN coatings are less understood than those of TiN, the well-known PVD coating material. This thesis anticipates to fill this technological gap. Along a wide range of experiments based on the deposition of CrN sub x coatings, XRD, SEM, SNMS and tribological an...

  7. Effect of glycine on the synthesis of CrN nanopowder using nitridation combustion synthesis precursors

    International Nuclear Information System (INIS)

    CrN nanopowder was synthesized by nitridation method using a combustion synthesis precursor derived from chromium nitrate and glycine mixed solution. Effects of glycine on the morphology and nitridation rate of the precursors, the particle size and morphology of synthesized CrN were studied in detail. The results indicated that Cr2O3 precursor with a high specific surface area of 162 m2 g−1 could be prepared by selecting an optimum molar ratio of glycine to chromium nitrate (G/C). Furthermore, a regular variation in the morphology of precursors had been observed with increasing (G/C). The nitridation products retained the morphology of Cr2O3 in the precursors. The nitridation products, prepared with (G/C = 4), comprised well-distributed spherical particles of CrN with the average size of 30 nm. Moreover, the nitridation rate of products with (G/C = 4) was significantly higher than that of the nitridation products prepared with (G/C = 0.5, 5/3, 3)

  8. Effect of glycine on the synthesis of CrN nanopowder using nitridation combustion synthesis precursors

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Zhiqin, E-mail: cao-zhi-qing@163.com; Qin, Mingli, E-mail: qinml@mater.ustb.edu.cn [University of Science and Technology Beijing, School of Materials Science and Engineering (China); Zuo, Chengyang [Pan Zhihua University, School of Materials Science and Engineering (China); Jia, Baorui; Liu, Ye; Gu, Yueru; Qu, Xuanhui [University of Science and Technology Beijing, School of Materials Science and Engineering (China)

    2015-02-15

    CrN nanopowder was synthesized by nitridation method using a combustion synthesis precursor derived from chromium nitrate and glycine mixed solution. Effects of glycine on the morphology and nitridation rate of the precursors, the particle size and morphology of synthesized CrN were studied in detail. The results indicated that Cr{sub 2}O{sub 3} precursor with a high specific surface area of 162 m{sup 2} g{sup −1} could be prepared by selecting an optimum molar ratio of glycine to chromium nitrate (G/C). Furthermore, a regular variation in the morphology of precursors had been observed with increasing (G/C). The nitridation products retained the morphology of Cr{sub 2}O{sub 3} in the precursors. The nitridation products, prepared with (G/C = 4), comprised well-distributed spherical particles of CrN with the average size of 30 nm. Moreover, the nitridation rate of products with (G/C = 4) was significantly higher than that of the nitridation products prepared with (G/C = 0.5, 5/3, 3)

  9. The bacterial effector DspA/E is toxic in Arabidopsis thaliana and is required for multiplication and survival of fire blight pathogen.

    Science.gov (United States)

    Degrave, Alexandre; Moreau, Manon; Launay, Alban; Barny, Marie-Anne; Brisset, Marie-Noëlle; Patrit, Oriane; Taconnat, Ludivine; Vedel, Regine; Fagard, Mathilde

    2013-06-01

    The type III effector DspA/E is an essential pathogenicity factor of the phytopathogenic bacterium Erwinia amylovora. We showed that DspA/E was required for transient bacterial growth in nonhost Arabidopsis thaliana leaves, as an E. amylovora dspA/E mutant was unable to grow. We expressed DspA/E in A. thaliana transgenic plants under the control of an oestradiol-inducible promoter, and found that DspA/E expressed in planta restored the growth of a dspA/E mutant. DspA/E expression in these transgenic plants led to the modulation by at least two-fold of the expression of 384 genes, mostly induced (324 genes). Both induced and repressed genes contained high proportions of defence genes. DspA/E expression ultimately resulted in plant cell death without requiring a functional salicylic acid signalling pathway. Analysis of A. thaliana transgenic seedlings expressing a green fluorescent protein (GFP):DspA/E fusion indicated that the fusion protein could only be detected in a few cells per seedling, suggesting the degradation or absence of accumulation of DspA/E in plant cells. Consistently, we found that DspA/E repressed plant protein synthesis when injected by E. amylovora or when expressed in transgenic plants. Thus, we conclude that DspA/E is toxic to A. thaliana: it promotes modifications, among which the repression of protein synthesis could be determinant in the facilitation of necrosis and bacterial growth. PMID:23634775

  10. InN nanorods prepared with CrN nanoislands by plasma-assisted molecular beam epitaxy

    Directory of Open Access Journals (Sweden)

    Young Sheng-Joue

    2011-01-01

    Full Text Available Abstract The authors report the influence of CrN nanoisland inserted on growth of baseball-bat InN nanorods by plasma-assisted molecular beam epitaxy under In-rich conditions. By inserting CrN nanoislands between AlN nucleation layer and the Si (111 substrate, it was found that we could reduce strain form Si by inserting CrN nanoisland, FWHM of the x-ray rocking curve measured from InN nanorods from 3,299 reduced to 2,115 arcsec. It is due to the larger strain from lattice miss-match of the film-like InN structure; however, the strain from lattice miss-match was obvious reduced owing to CrN nanoisland inserted. The TEM images confirmed the CrN structures and In droplets dissociation from InN, by these results, we can speculate the growth mechanism of baseball-bat-like InN nanorods.

  11. Pollen-Specific Aquaporins NIP4;1 and NIP4;2 Are Required for Pollen Development and Pollination in Arabidopsis thaliana.

    Science.gov (United States)

    Di Giorgio, Juliana Andrea Pérez; Bienert, Gerd Patrick; Ayub, Nicolás Daniel; Yaneff, Agustín; Barberini, María Laura; Mecchia, Martín Alejandro; Amodeo, Gabriela; Soto, Gabriela Cynthia; Muschietti, Jorge Prometeo

    2016-05-01

    In flowers with dry stigmas, pollen development, pollination, and pollen tube growth require spatial and temporal regulation of water and nutrient transport. To better understand the molecular mechanisms involved in reproductive processes, we characterized NIP4;1 and NIP4;2, two pollen-specific aquaporins of Arabidopsis thaliana. NIP4;1 and NIP4;2 are paralogs found exclusively in the angiosperm lineage. Although they have 84% amino acid identity, they displayed different expression patterns. NIP4;1 has low expression levels in mature pollen, while NIP4;2 expression peaks during pollen tube growth. Additionally, NIP4;1pro:GUS flowers showed GUS activity in mature pollen and pollen tubes, whereas NIP4;2pro:GUS flowers only in pollen tubes. Single T-DNA mutants and double artificial microRNA knockdowns had fewer seeds per silique and reduced pollen germination and pollen tube length. Transport assays in oocytes showed NIP4;1 and NIP4;2 function as water and nonionic channels. We also found that NIP4;1 and NIP4;2 C termini are phosphorylated by a pollen-specific CPK that modifies their water permeability. Survival assays in yeast indicated that NIP4;1 also transports ammonia, urea, boric acid, and H2O2 Thus, we propose that aquaporins NIP4;1 and NIP4;2 are exclusive components of the reproductive apparatus of angiosperms with partially redundant roles in pollen development and pollination. PMID:27095837

  12. Corrosion behavior of Zr modified CrN coatings using metal vapor vacuum arc ion implantation

    International Nuclear Information System (INIS)

    In recent years, attention has focused on the use of alternative metal nitride coatings as replacements for TiN for not only improved wear resistance and surface hardness but also for increased corrosion resistance in selected environments. While these coatings display excellent wear resistance and surface hardness, like many nitride coatings, their corrosion behavior is determined to a large extent by the presence of defects such as pinholes within the coating. Improved corrosion resistance is expected through minimizing the porosity/number of pinholes within the coating, through postdeposition surface modification. The aim of this study was to modify the surface of CrN coatings using metal vapor vacuum arc ion implantation. CrN coatings were deposited on AISI 316 stainless steel and AISI 1020 mild steel substrates using physical vapor deposition technology, followed by implantation of Zr ions into the coating at doses varying from 6x1016 to 2x1017 ions/cm2. The corrosion behavior was assessed in saline environments using linear polarization techniques and the corroded surface of the coatings was characterized using x-ray photoelectron spectroscopy and scanning electron microscopy. The results of the study showed that implantation of Zr ions into CrN resulted in a lowering of the corrosion current density, suggesting improved corrosion resistance. This was though to be associated with two factors. Firstly, partial closure of the pinholes as a result of the implantation process and secondly, the formation of ZrN, CrZrN, and various oxynitrides/oxides at the surface

  13. Cognitive Radio Network (CRN) System for Vehicle Safety Applications

    OpenAIRE

    Lim, Jae Han

    2014-01-01

    As the number of vehicle accidents increases, car manufacturers and academic researchers have developed a vehicular safety system. The key component of the safety system is vehicular communications, by which vehicles exchange their local status information with neighbor vehicles and disseminate a warning message within a specified area. The challenge lies in satisfying stringent communication requirements of the safety system, extremely reliable packet delivery and low communication latency. ...

  14. CRN13 candidate effectors from plant and animal eukaryotic pathogens are DNA-binding proteins which trigger host DNA damage response.

    Science.gov (United States)

    Ramirez-Garcés, Diana; Camborde, Laurent; Pel, Michiel J C; Jauneau, Alain; Martinez, Yves; Néant, Isabelle; Leclerc, Catherine; Moreau, Marc; Dumas, Bernard; Gaulin, Elodie

    2016-04-01

    To successfully colonize their host, pathogens produce effectors that can interfere with host cellular processes. Here we investigated the function of CRN13 candidate effectors produced by plant pathogenic oomycetes and detected in the genome of the amphibian pathogenic chytrid fungus Batrachochytrium dendrobatidis (BdCRN13). When expressed in Nicotiana, AeCRN13, from the legume root pathogen Aphanomyces euteiches, increases the susceptibility of the leaves to the oomycete Phytophthora capsici. When transiently expressed in amphibians or plant cells, AeCRN13 and BdCRN13 localize to the cell nuclei, triggering aberrant cell development and eventually causing cell death. Using Förster resonance energy transfer experiments in plant cells, we showed that both CRN13s interact with nuclear DNA and trigger plant DNA damage response (DDR). Mutating key amino acid residues in a predicted HNH-like endonuclease motif abolished the interaction of AeCRN13 with DNA, the induction of DDR and the enhancement of Nicotiana susceptibility to P. capsici. Finally, H2AX phosphorylation, a marker of DNA damage, and enhanced expression of genes involved in the DDR were observed in A. euteiches-infected Medicago truncatula roots. These results show that CRN13 from plant and animal eukaryotic pathogens promotes host susceptibility by targeting nuclear DNA and inducing DDR. PMID:26700936

  15. The Membrane-Associated Sec1/Munc18 KEULE is Required for Phragmoplast Microtubule Reorganization During Cytokinesis in Arabidopsis.

    Science.gov (United States)

    Steiner, Alexander; Müller, Lin; Rybak, Katarzyna; Vodermaier, Vera; Facher, Eva; Thellmann, Martha; Ravikumar, Raksha; Wanner, Gerhard; Hauser, Marie-Theres; Assaad, Farhah F

    2016-04-01

    Cytokinesis, the partitioning of the cytoplasm following nuclear division, requires extensive coordination between membrane trafficking and cytoskeletal dynamics. In plants, the onset of cytokinesis is characterized by the assembly of a bipolar microtubule array, the phragmoplast, and of a transient membrane compartment, the cell plate. Little is known about the coordination between membrane deposition at the cell plate and the dynamics of phragmoplast microtubules. In this study, we monitor the localization dynamics of microtubule and membrane markers throughout cytokinesis. Our spatiotemporal resolution is consistent with the general view that microtubule dynamics drive membrane movements. Nonetheless, we provide evidence for active sorting at the cell plate and show that this is, at least in part, mediated by the TRAPPII tethering complex. We also characterize phragmoplast microtubule organization and cell plate formation in a suite of cytokinesis-defective mutants. Of four mutant lines with defects in phragmoplast microtubule organization, only mor1 microtubule-associated mutants exhibited aberrant cell plates. Conversely, the mutants with the strongest impairment in phragmoplast microtubule reorganization are keule alleles, which have a primary defect in membrane fusion. Our findings identify the SEC1/Munc18 protein KEULE as a central regulatory node in the coordination of membrane and microtubule dynamics during plant cytokinesis. PMID:26700031

  16. Evaluation of anti-scale property of CrN coatings at high temperature and high pressure

    International Nuclear Information System (INIS)

    It is well known that oxide scale which adheres to the inner wall of the nozzle in nuclear power plant causes a serious problem. This study was carried out to obtain the knowledge about initiation and deposition behavior of oxide scale on the surface of SUS304 stainless steel and the evaluation of anti-scale property of chromium nitride (CrN) coatings at high temperature and high pressure. SUS304 stainless steel and CrN coating specimens were heated in water up to 200degC for more than 250 hours. Obtained results are summarized as follows. Initiation of the scale started from corrosive part of SUS304 stainless steel and the scale grows by deposition of magnetite particles. CrN coating can be applied to prevent the initiation and deposition of oxide scale. (author)

  17. Analytical electron microscopy of interface layers between Ti(6% Al, 4% V) and a CrN cathodic arc coating

    International Nuclear Information System (INIS)

    This paper reports on the applications of analytical electron microscopy to the study of cathodic arc deposited CrN coating on a Ti(6% Al, 4% V) substrate. Particular attention is given to analysis of the coating/substrate interface. Electron energy loss spectroscopy is used to show that the Cr sputter cleaning of the Ti(6% Al, 4% V) results in penetration of Cr into the substrate giving a bcc alloy layer whose composition varies from Ti(6% Al, 4% V) at the substrate interface to almost pure Cr at the coating interface. Subsequent deposition of CrN results in an initial deposition of sub-stoichiometric Cr2N followed by sub-stoichiometric CrN with a } 022{ texture and a columnar structure. The degree of sub-stoichiometry of the nitrides depends on the substrate bias and the substrate orientation relative to the cathode. (author)

  18. XAS Study on the Intermediate Species Formed During the Surface Oxidation of CrN Films

    OpenAIRE

    Esaka, F.; Furuya, K.; Shimada, H.; Imamura, M.; Matsubayashi, N.; Sato, T.; Nishijima, A.; Kikuchi, T.; Kawana, A.; Ichimura, H.

    1997-01-01

    XAS was applied to the identification of the intermediate species formed during the surface oxidation of CrN films. The N K-edge XAS spectra indicated formation of an intermediate species which gave a feature at 401.4 eV. A high resolution XAS spectrum exhibited that the feature at 401.4 eV has the same vibration splitting as that of gaseous N2. It was also found that the species assigned to molecular N2 occurred in the interstitial position of the surface oxide layer in the oxidized films. T...

  19. The properties and wear resistance of the CrN PVD coatings

    OpenAIRE

    M. Polok-Rubiniec; L.A. Dobrzański; M. Adamiak

    2008-01-01

    Purpose: The aim of the paper is comparison of the mechanical properties and wear resistance of the monolayer CrN PVD coatings deposited onto heat treated and plasma nitrited X37CrMoV5-1 type hot work tool steel.Design/methodology/approach: The microhardness tests of the PVD coatings were made on the dynamic ultra-microhardness tester. The surfaces’ thopography and the structure of the PVD coatings was observed on the scanning electron microscopy. The evaluation of the adhesion of co...

  20. Lightest Isotope of Bh Produced via the 209Bi(52Cr,n)260Bh Reaction

    International Nuclear Information System (INIS)

    The lightest isotope of Bh was produced in the new 209Bi(52Cr,n)260Bh reaction at the Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. Positive identification was made by observation of eight correlated alpha particle decay chains in the focal plane detector of the Berkeley Gas-Filled Separator. 260Bh decays with a 35-9+19 ms half-life by alpha particle emission mainly by a group at 10.16 MeV. The measured cross section of 59-20+29 pb is compared to model predictions. The influence of the N=152 and Z=108 shells on alpha decay properties is discussed

  1. SETH1 and SETH2, Two Components of the Glycosylphosphatidylinositol Anchor Biosynthetic Pathway, Are Required for Pollen Germination and Tube Growth in Arabidopsis

    Czech Academy of Sciences Publication Activity Database

    Lalanne, E.; Honys, David; Johnson, A.; Borner, G. H. H.; Lilley, K. S.; Dupree, P.; Grossniklaus, U.; Twell, D.

    2003-01-01

    Roč. 16, - (2003), s. 229-240. ISSN 1040-4651 R&D Projects: GA AV ČR IAA5038207 Institutional research plan: CEZ:AV0Z5038910 Keywords : Glycosylphosphatidylinositol * Pollen Germination * Arabidopsis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 10.679, year: 2003

  2. Influence of nitrogen flow rates on materials properties of CrN films grown by reactive magnetron sputtering

    Indian Academy of Sciences (India)

    B Subramanian; K Prabakaran; M Jayachandran

    2012-08-01

    Chromium nitride (CrN) hard thin films were deposited on different substrates by reactive direct current (d.c.) magnetron sputtering with different nitrogen flow rates. The X-ray diffraction patterns showed mixed Cr2N and CrN phases. The variations in structural parameters are discussed. The grain size increased with increasing nitrogen flow rates. Scanning electron microscopy image showed columnar and dense microstructure with varying nitrogen flow rates. An elemental analysis of the samples was realized by means of energy dispersive spectroscopy. The electrical studies indicated the semiconducting behaviour of the films at the nitrogen flow rate of 15 sccm.

  3. Structural and biochemical characterization of CRN-5 and Rrp46: An exosome component participating in apoptotic DNA degradation

    OpenAIRE

    Yang, Che-Chuan; Wang, Yi-Ting; Hsiao, Yu-Yuan; Doudeva, Lyudmila G.; Kuo, Pan-Hsien; Chow, Sih Yao; Yuan, Hanna S.

    2010-01-01

    Rrp46 was first identified as a protein component of the eukaryotic exosome, a protein complex involved in 3′ processing of RNA during RNA turnover and surveillance. The Rrp46 homolog, CRN-5, was subsequently characterized as a cell death-related nuclease, participating in DNA fragmentation during apoptosis in Caenorhabditis elegans. Here we report the crystal structures of CRN-5 and rice Rrp46 (oRrp46) at a resolution of 3.9 Å and 2.0 Å, respectively. We found that recombinant human Rrp46 (h...

  4. Effect of nitrogen flow rate on properties of CrN films Prepared by HCD-gun

    OpenAIRE

    A.J. Novinrooz; H. Seyedi

    2006-01-01

    Purpose: The effect of reactant nitrogen gas flow rate on the tribological properties of CrN thin films was studied.Design/methodology/approach: Hollow Cathode Discharge gun (HCD-gun) was employed for the coating of CrN films on the glass and SS-316 sub strum. The reactant nitrogen with different flow was fed in to the vacuum chamber of 3x10-3 Pa pressure to form Cr N composite under experimental condition.Findings: The crystalline phase and micro structural studies of the specimens were carr...

  5. Microstructure and mechanical properties of Cr-N coatings by ion-beam-assisted magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Tian Linhai [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Zhu Xiaodong [State Key Laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Tang, Bin [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)], E-mail: tangbin@tyut.edu.cn; Pan Junde [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); He Jiawen [State Key Laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2008-06-15

    Cr-N coatings were deposited using the ion-beam-assisted magnetron sputtering technique. The microstructure and mechanical properties of Cr-N coatings were found to be dependent on the ion bombardment energy. The microstructure of the coatings changes from columnar structure to fine and dense grains when the ion bombardment energy increases from 0 to 800 eV and to equiaxial grains for an ion energy of 1200 eV. The coatings average grain size, which is determined by the Voigt profile function, decreases from 20.3 nm at an ion energy of 0 eV to 8.8 nm at 800 eV and further increases to 21.5 nm at 1200 eV. Both the hardness and fracture toughness of the coatings are improved when the ion energy increases from 0 to 800 eV, which is related to the decrease of grain size. The grain size of the coating grown at an energy of 1200 eV is close to that of 0 eV, but the hardness and fracture toughness at 1200 eV are higher. This suggests that the improvement of hardness and fracture toughness is also related to the increased densification of the coatings caused by ion bombardment.

  6. HEXOKINASE 1 is required for glucose-induced repression of bZIP63, At5g22920 and BT2 in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Sabine eKunz

    2015-07-01

    Full Text Available Simple sugars, like glucose and sucrose, act as signals to modulate the expression of hundreds of genes in plants. Frequently, however, it remains unclear whether this regulation is induced by the sugars themselves or by their derivatives generated in the course of carbohydrate (CH metabolism. In the present study, we tested the relevance of different CH metabolism and allocation pathways affecting expression patterns of five selected sugar-responsive genes (bZIP63, At5g22920, BT2, MGD2 and TPS9 in Arabidopsis thaliana. In general, the expression followed diurnal changes in the overall sugar availability. However, under steady growth conditions, this response was hardly impaired in the mutants for CH metabolizing/ transporting proteins (adg1, sex1, sus1-4, sus5/6 and tpt2, including also hexokinase1 (HXK1 loss- and gain-of-function plants - gin2.1 and oe3.2, respectively. In addition, transgenic plants carrying pbZIP63::GUS showed no changes in reporter-gene-expression when grown on sugar under steady-state conditions. In contrast, short-term treatments of agar-grown seedlings with 1% glucose or sucrose induced pbZIP63::GUS repression, which became even more apparent in seedlings grown in liquid media. Subsequent analyses of liquid-grown gin2.1 and oe3.2 seedlings revealed that glucose-dependent regulation of the five selected genes was not affected in gin2.1, whereas it was enhanced in oe3.2 plants for bZIP63, At5g22920 and BT2. The sugar treatments had no effect on ATP/ADP ratio, suggesting that changes in gene expression were not linked to cellular energy status. Overall, the data suggest that HXK1 does not act as glucose sensor controlling bZIP63, At5g22920 and BT2 expression, but it is nevertheless required for production of a downstream metabolic signal regulating their expression.

  7. A plasma membrane H+-ATPase is required for the formation of proanthocyanidins in the seed coat endothelium of Arabidopsis thaliana

    OpenAIRE

    Ivan R Baxter; Young, Jeffery C.; Armstrong, Gordon; Foster, Nathan; Bogenschutz, Naomi; Cordova, Tatiana; Peer, Wendy Ann; Hazen, Samuel P.; Murphy, Angus S.; Harper, Jeffrey F.

    2005-01-01

    The plasma membrane in plant cells is energized with an electrical potential and proton gradient generated through the action of H+ pumps belonging to the P-type ATPase superfamily. The Arabidopsis genome encodes 11 plasma membrane H+ pumps. Auto-inhibited H+-ATPase isoform 10 (AHA10) is expressed primarily in developing seeds. Here we show that four independent gene disruptions of AHA10 result in seed coats with a transparent testa (tt) phenotype (light-colored seeds). A quantitative analysi...

  8. Influence of nitrogen content on the structural, electrical and mechanical properties of CrN x thin films

    International Nuclear Information System (INIS)

    CrN x films were prepared using 20 kHz medium magnetron frequency magnetron sputtering in order to analyze the structural and mechanical features regarding to N2 content variations. XRD diffraction patterns reveal that only Cr phase with strong [1 1 1] orientation is observed for 0% nitrogen contents, the mixed Cr2N and Cr phases appear at 20% nitrogen content, while for 40% N2 content, no crystal structure feature is seen, indicating that an amorphous phase is generated. Further increasing the nitrogen content to 60% or above, only CrN phase appeared. SEM image shows a columnar-type structure lying in the transition zone between T and I zones of Thornton Model for the films. The critical load (L c) are 23 and 14 g for the Cr films and CrN x (x > 0) films, respectively. The Cr film (0% N2 content) shows a low friction coefficient against the steel ball, but much higher against the Si3N4 ball. The friction coefficient of the CrN x films is lower in the range of nitrogen content from 20 and 40%, and then reached about 0.7, no obvious changes was observed with the N2 content further increasing

  9. Influence of silicon content on the microstructure and hardness of CrN coatings deposited by reactive magnetron sputtering

    International Nuclear Information System (INIS)

    CrN and CrSiN films were deposited on the stainless steel and silicon substrates by DC magnetron sputtering and their microstructural features were investigated by X-ray diffraction (XRD), scanning electron microscope (FE-SEM/EDS), and atomic force microscopy (AFM). The influence of Si content along with process parameters such as power on the microstructural characteristics of Cr-Si-N and CrN films were investigated and compared between each other. The power and increasing Si contents strongly influence the microstructural and hardness of the deposited films. XRD analysis of the coatings indicates a grain refinement with increase in Si content during deposition of coatings, which is tandem with AFM and SEM results. Also, the surface roughness and particle size are decreasing with addition of Si in the films. The hardness of CrN and CrSiN was measured by microhardness tester and found that introduction of Si content in the CrN system increases its hardness from 1839 Hv to 2570 Hv.

  10. Effect of metal vapor vacuum arc Cr-implanted interlayers on the microstructure of CrN film on silicon

    International Nuclear Information System (INIS)

    The effect of metal vapor vacuum arc (MEVVA) Cr-implanted interlayers on the microstructure of CrN films on the silicon wafer was investigated. Two types of the CrN-coated specimens (CrN/Si and CrN/Cr/Si) by cathodic arc plasma deposition were prepared with and without a MEVVA Cr-implanted interlayer. The diffraction patterns of the coated specimens revealed the presence of CrN, and the (220) preferred orientation for both CrN/Si and CrN/CrN/Si. The CrN coating thicknesses for CrN/Si and for CrN/Cr/Si were 0.3 μm and 1.3 μm, respectively. Secondary ion mass spectrometry proved the high quality of the films on silicon substrates. Transmission electron microscopy micrographs and selective area diffractions revealed the presence of a large number of nano-scale Cr resulting from the interlayer of MEVVA Cr with a background of single crystal silicon spots. Furthermore, in situ stress measurement demonstrated that the presence of a Cr interlayer between CrN and Si could drastically reduce the residual stress in the CrN/Cr/Si assembly

  11. Cyclic nanoindentation studies on CrN thin films prepared by RF sputtering on Zr-based metallic glass

    International Nuclear Information System (INIS)

    Cyclic nanoindentation tests were carried out to study the influence of the chromium nitride thin films on the mechanical properties of Zr-based metallic glass. Chromium nitride thin coatings have been deposited on Zr50Cu40Al10 metallic glass substrate by RF sputtering. The deposition process was done at room temperature under nitrogen reactive gas using a metallic chromium target. The CrN films have a thickness of 300 nm. Several cyclic nanoindentation measurements were conducted on CrN films and Zr50Cu40Al10 metallic glass substrate samples at various loading rate values. We have found that the coated metallic glass sample shows high mechanical properties such as hardness and reduced elastic modulus. Cyclic nanoindentation results show a hardening behaviour for these CrN coatings. Moreover, the CrN coated on Zr-based metallic glass was found to have a high value of resistance to crack propagation, as being analysed through the SEM pictures of the residual Vickers indentation impressions.

  12. Arabidopsis VILLIN2 and VILLIN3 Are Required for the Generation of Thick Actin Filament Bundles and for Directional Organ Growth[C][W

    Science.gov (United States)

    van der Honing, Hannie S.; Kieft, Henk; Emons, Anne Mie C.; Ketelaar, Tijs

    2012-01-01

    In plant cells, actin filament bundles serve as tracks for myosin-dependent organelle movement and play a role in the organization of the cytoplasm. Although virtually all plant cells contain actin filament bundles, the role of the different actin-bundling proteins remains largely unknown. In this study, we investigated the role of the actin-bundling protein villin in Arabidopsis (Arabidopsis thaliana). We used Arabidopsis T-DNA insertion lines to generate a double mutant in which VILLIN2 (VLN2) and VLN3 transcripts are truncated. Leaves, stems, siliques, and roots of vln2 vln3 double mutant plants are twisted, which is caused by local differences in cell length. Microscopy analysis of the actin cytoskeleton showed that in these double mutant plants, thin actin filament bundles are more abundant while thick actin filament bundles are virtually absent. In contrast to full-length VLN3, truncated VLN3 lacking the headpiece region does not rescue the phenotype of the vln2 vln3 double mutant. Our results show that villin is involved in the generation of thick actin filament bundles in several cell types and suggest that these bundles are involved in the regulation of coordinated cell expansion. PMID:22209875

  13. Arabidopsis VILLIN2 and VILLIN3 are required for the generation of thick actin filament bundles and for directional organ growth.

    Science.gov (United States)

    van der Honing, Hannie S; Kieft, Henk; Emons, Anne Mie C; Ketelaar, Tijs

    2012-03-01

    In plant cells, actin filament bundles serve as tracks for myosin-dependent organelle movement and play a role in the organization of the cytoplasm. Although virtually all plant cells contain actin filament bundles, the role of the different actin-bundling proteins remains largely unknown. In this study, we investigated the role of the actin-bundling protein villin in Arabidopsis (Arabidopsis thaliana). We used Arabidopsis T-DNA insertion lines to generate a double mutant in which VILLIN2 (VLN2) and VLN3 transcripts are truncated. Leaves, stems, siliques, and roots of vln2 vln3 double mutant plants are twisted, which is caused by local differences in cell length. Microscopy analysis of the actin cytoskeleton showed that in these double mutant plants, thin actin filament bundles are more abundant while thick actin filament bundles are virtually absent. In contrast to full-length VLN3, truncated VLN3 lacking the headpiece region does not rescue the phenotype of the vln2 vln3 double mutant. Our results show that villin is involved in the generation of thick actin filament bundles in several cell types and suggest that these bundles are involved in the regulation of coordinated cell expansion. PMID:22209875

  14. Corrosion and electrical properties of CrN- and TiN-coated 316L stainless steel used as bipolar plates for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Cathode arc ion plating was applied to deposit CrN and TiN coating layers on stainless steel 316L (SS316L) to produce metallic bipolar plates for polymer electrolyte membrane fuel cells (PEMFCs). The interfacial contact resistance between samples and carbon paper was measured and found to be 10 and 23 mΩ ∗ cm2 for TiN and CrN coating layer respectively under 150 N cm−2 compaction forces. The corrosion properties were investigated in the operating environments of PEMFC. While TiN coating layer was dissolved in the operating environments of PEMFC, the corrosion current density of 0.1 μA cm−2 was obtained for CrN coating layer at anodic condition and its protective efficiency was revealed as 99%. This analysis indicates that the improvement may be attributed to the extremely dense coating and the synergistic function of the CrN layered structure. - Highlights: ► CrN and TiN are deposited on the surface of SS316L by cathode arc ion plating. ► Coating layers of CrN and TiN lead to high electrical conductivity. ► CrN coating layer provides higher corrosion resistance than TiN coating layer

  15. Growth and structure of CrN nanoislands on Cu(001) studied by scanning tunneling microscopy and X-ray photoemission spectroscopy

    International Nuclear Information System (INIS)

    We report a method for the fabrication of high structural quality CrN nanoislands on Cu(001). The CrN nanoislands can be fabricated in ultrahigh vacuum conditions by means of Cr atoms deposition on saturated Cu(001)c(2 × 2)-N surface and subsequent annealing at 500 °C. Existence of two types of nanoislands is shown by scanning tunneling microscopy investigations with atomic resolution for different CrN nanoislands formed on surface with 0.35 monolayer Cr coverage. The measured in-plane lattice constant (a = 0.39 ± 0.01 nm) of the CrN nanoislands is 8% larger than the Cu substrate lattice. X-ray photoemission spectroscopy investigations reveal chromium nitride phase transition from CrN to Cr2N associated with changes of Cr concentration. - Highlights: ► We develop a method for the fabrication of CrN nanoislands on Cu(001). ► Growth of two types of CrN nanoislands is shown by scanning tunneling microscopy. ► Chromium nitride phase transition is shown by X-ray photoemission spectroscopy

  16. Synergistic interaction of CLAVATA1, CLAVATA2, and RECEPTOR-LIKE PROTEIN KINASE 2 in cyst nematode parasitism of Arabidopsis

    Science.gov (United States)

    Plant-parasitic cyst nematodes secrete CLAVATA3 (CLV3)/ENDOSPERM SURROUNDING REGION (ESR) (CLE)-like effector proteins. These proteins act as ligand mimics of plant CLE peptides and are required for successful nematode infection. Previously, we showed that CLV2 and CORYNE (CRN), a heterodimer recept...

  17. Effect of negative bias voltage on CrN films deposited by arc ion plating. II. Film composition, structure, and properties

    International Nuclear Information System (INIS)

    Chromium nitride (CrN) films were deposited on Si wafers by arc ion plating at various negative bias voltages and several groups of N2/Ar gas flux ratios and chamber gas pressures. The authors systematically investigated the influence of negative bias voltage on the synthesis, composition, microstructure, and properties of the arc ion plating (AIP) CrN films. In this article, the authors investigated the influence of negative bias voltage on the chemical composition, structure, and mechanical properties of the CrN films. The results showed that the chemical composition and phase structure of the AIP CrN films were greatly altered by application of negative bias voltage. Due to the selective resputtering effect, substoichiometric CrN films were obtained. With increase in bias voltages, the main phases in the films transformed from Cr+CrN to Cr2N at low N2/Ar flow ratios, whereas the films at high N2/Ar flow ratios retained the CrN phase structure. The CrN films experienced texture transformation from CrN (200) to CrN (220), and Cr2N (300) to Cr2N(300)+Cr2N(110). Increase in negative bias voltage also resulted in microstructure evolution of coarse columnar grains→fine columnar grains→quasiamorphous microstructure→recrystallized structures. From the experimental results, the authors proposed a new structure zone model based on enhanced bombardment of incident ions by application of negative bias voltage. The influence of negative bias voltage on the microhardness and residual stresses of the films and the inherent mechanisms were also explored

  18. Climate change and its impact on the Crn Drim Catchment Area In Macedonia

    International Nuclear Information System (INIS)

    In this paper it will be presented the overview of the climate change and climate regimes of the world in general according different scenarios in the latest assessment (the 3d Report published in 2001) of the Intergovernmental Panel on Climate Change (IPCC) and its impact on the Crn Drim catchment area in Macedonia.This analysis and interpretation only provides a preliminary investigation into climate change and how it will affect Ohrid and Prespa lake system as a part of Crn Drim catchment area, which is already attacked by the climate changed. From the climatological aspect two elements: temperature and rainfall, will be' calculated and their expected changes over the century in the same area. Dates used in these analyses are from the Hydro meteorological Service of Republic of Macedonia archives In the graphs are shown changes in average seasonal climate for the period around the 2080s, relative to 1961-1990 climate. Results are shown for the SRES A2 scenario, which assumes a future world of fairly conventional energy development, i.e., continuing dependence on fossil carbon fuels. The projections for average seasonal climate for temperature and precipitation are estimated and shown separately for two seasons: winter and summer. The estimated values are compared with annual mean global worming for the 2080s,-and for the SRES A2 scenario, as calculated by the IPCC (a value of about 3.2oC). The results show rate of worming greater in summer than in winter for Ohrid Lake as well as for Prespa Lake. Concerning the precipitation, it increases slightly in winter and decreases substantially in summer, by around 30 per cent. As the conclusion it is obviously that the temperature will rise in all Crn Drim catchment area with implications for increasing water temperature and water quality, which would be degraded by higher water temperature. This will increase evaporation and as the results can be expected water level decreasing. Also, higher temperatures and heat waves

  19. CrN precipitation and elemental segregation during the decay of expanded austenite

    Science.gov (United States)

    Manova, D.; Lotnyk, A.; Mändl, S.; Neumann, H.; Rauschenbach, B.

    2016-06-01

    Nitrogen insertion into austenitic stainless steel at elevated temperatures leads to anomalous fast nitrogen diffusion and the formation of an expanded fcc phase which is known as expanded austenite. In situ x-ray diffraction measurements during low energy nitrogen ion implantation into steel AISI 304 at 475 °C and short annealing at 575 °C were performed in conjunction with transmission electron microscopy investigations. They show the time dependent decay of this expanded phase with coalescing and growing CrN precipitates. There is elemental segregation associated with this decay where Fe is absent very early from the Cr–N containing precipitates. Ni is segregating towards the Fe-rich matrix more slowly. At the same time, the microstructure—decayed phase vs expanded austenite—is visible in SIMS cluster analysis.

  20. TiN and CrN PVD coatings on electroless nickel-coated steel substrates

    International Nuclear Information System (INIS)

    Plasma-assisted (PA) PVD ceramic coatings such as TiN have so far achieved only very limited use on cheap low-alloy steels, owing to problems relating to both corrosion resistance and the need for load support from the underlying material. Here we report tests to assess the wear and corrosion performance of TiN and CrN PAPVD coatings on phosphorus-doped electroless nickel (ENiP)-coated steels. It is shown that this route offers a potentially cost-effective means of utilising PAPVD ceramic films on lower grade steels. In particular, CrN/ENiP on AISI 304 stainless steel is shown to exhibit a promising combination of wet abrasion resistance with good corrosion properties. (orig.)

  1. Ion-beam irradiation effects on reactively sputtered CrN layers

    OpenAIRE

    Mirjana Novaković; Maja Popović; Nataša Bibić

    2011-01-01

    This paper presents a study of microstructural changes induced in CrN layers by irradiation with 120 keV argon ions. The layers were deposited on (100) Si wafers, at different nitrogen partial pressures (2×10^-4, 3.5×10^-4 and 5×10^-4 mbar), to a total thickness of 260–280 nm. During deposition the substrates were held at 150°C. After deposition the samples were irradiated with argon ions to the fluences of 1×10^15 and 1×10^16 ions/cm2, under the vacuum of 7×10^-6 mbar. Characterisation of th...

  2. Tribology of ZRN, CRN and TIALN thin films deposited by reactive magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Alexander Ruden

    2013-01-01

    Full Text Available El coeficiente de fricción y el coeficiente de desgaste, representan dos variables importantes para la elección de recubrimientos duros en aplicaciones críticas de ingeniería tales como corte y conformado de materiales. Para explicar de manera profunda estas variables, es necesario conocer los diferentes tipos de desgaste que ocurren en estas superficies recubiertas. Se han evaluado recubrimientos de nitruro de circonio (ZrN, nitruro de cromo (CrN y nitruro de titanio aluminio (TiAlN, producidos por la técnica magnetrón sputtering reactivo, determinando las propiedades tribológicas, midiendo coeficientes de fricción (COF y desgaste, y mostrando un análisis de los mecanismos de desgaste presentes para cada recubrimiento durante el contacto tribológico en sistemas cerámicos. Se observó que el voltaje de polarización incrementa las fallas por deformación plástica y la generación de un tercer cuerpo en la superficie del ZrN. El aumento del flujo de nitrógeno en la deposición de CrN, mejora el comportamiento tribológico al segregar la fase cúbica del material, optimizando sus propiedades superficiales. Al incrementar la temperatura de deposición del TiAlN se mejora su calidad superficial (reducción de rugosidad y densidad de poros, reduciendo la abrasión y aumentando la capacidad de carga del compuesto.

  3. JMJ14, a JmjC domain protein, is required for RNA silencing and cell-to-cell movement of an RNA silencing signal in Arabidopsis

    OpenAIRE

    Searle, I.R.; Melnyk, C. W.; Baulcombe, D. C.; Smith, L. M.; Pontes, O.

    2010-01-01

    JMJ14 is a histone H3 Lys4 (H3K4) trimethyl demethylase that affects mobile RNA silencing in an Arabidopsis transgene system. It also influences CHH DNA methylation, abundance of endogenous transposon transcripts, and flowering time. JMJ14 acts at a point in RNA silencing pathways that is downstream from RNA-dependent RNA polymerase 2 (RDR2) and Argonaute 4 (AGO4). Our results illustrate a link between RNA silencing and demethylation of histone H3 trimethylysine. We propose that JMJ14 acts do...

  4. What Does a Mean Really Mean? Interpreting Mainstem Detrital CRN Data in Transient Landscapes, South Fork Eel River, CA

    Science.gov (United States)

    Crosby, B. T.; Rowland, J. C.

    2011-12-01

    In landscapes with steady, uniform erosion rates, mainstem detrital cosmogenic radionuclide (CRN) concentrations are expected to reflect basin-wide erosion rates. In this study, we use both field and numerical experiments to provide new insight into how these rates will vary in over space and time during transient landscape adjustment. Our field data come from the South Fork Eel River (SFER) in Northern California where well-aligned knickpoints and terraces along the mainstem and tributary channels define a clear boundary between an incised, actively adjusting lowland and an unadjusted relict upland landscape. This transient adjustment is most complete in the lower portion of the basin and becomes progressively less extensive upstream, consistent with an upstream propagating wave of adjustment. To test if detrital CRN erosion rates would reflect this transient adjustment, we collected 9 sand samples along the mainstem SFER at sites distributed between the headwaters and the basin outlet. CRN erosion rates increase systematically down the mainstem from 0.22 to 0.52 mm/yr. This gradual increase in erosion rate reflects the progressive dilution of relict high CRN concentrations by low CRN concentration sediment from the rapidly eroding, adjusting regions downstream. Using a simple, two member sediment mixing model, we find that CRN concentrations should decrease in a non-linear manner as the proportion of the basin in the adjusting state increases. In order to test this non-linear dilution theory, we use the mapped boundary between the relict and adjusting regions in the SFER to quantify, for each mainstem sample site, the fraction of upstream drainage area that is in a relict state. Because the adjustment is relatively immature, our samples only range from 75% to 98% relict, but fall along the predicted mixing line. Because detrital CRN erosion rate data from any field site only provides a single snapshot of contemporary erosion rates, we employ the CHILD numerical

  5. Arabidopsis TAF1 is an MRE11-interacting protein required for resistance to genotoxic stress and viability of the male gametophyte.

    Science.gov (United States)

    Waterworth, Wanda M; Drury, Georgina E; Blundell-Hunter, George; West, Christopher E

    2015-11-01

    Repair of DNA double-strand breaks (DSBs) by recombination pathways is essential for plant growth and fertility. The recombination endonuclease MRE11 plays important roles in sensing and repair of DNA DSBs. Here we demonstrate protein interaction between Arabidopsis MRE11 and the histone acetyltransferase TAF1, a TATA-binding protein Associated Factor (TAF) of the RNA polymerase II transcription initiation factor complex TFIID. Arabidopsis has two TAF1 homologues termed TAF1 and TAF1b and mutant taf1b lines are viable and fertile. In contrast, taf1 null mutations are lethal, demonstrating that TAF1 is an essential gene. Heterozygous taf1+/- plants display abnormal segregation of the mutant allele resulting from defects in pollen tube development, indicating that TAF1 is important for gamete viability. Characterization of an allelic series of taf1 lines revealed that hypomorphic mutants are viable but display developmental defects and reduced plant fertility. Hypersensitivity of taf1 mutants lacking the C-terminal bromodomain to X-rays and mitomycin C, but not to other forms of abiotic stress, established a specific role for TAF1 in plant DNA repair processes. Collectively these studies reveal a function for TAF1 in plant resistance to genotoxic stress, providing further insight into the molecular mechanisms of the DNA damage response in plants. PMID:26358508

  6. Floral Induction in Arabidopsis by FLOWERING LOCUS T Requires Direct Repression of BLADE-ON-PETIOLE Genes by the Homeodomain Protein PENNYWISE.

    Science.gov (United States)

    Andrés, Fernando; Romera-Branchat, Maida; Martínez-Gallegos, Rafael; Patel, Vipul; Schneeberger, Korbinian; Jang, Seonghoe; Altmüller, Janine; Nürnberg, Peter; Coupland, George

    2015-11-01

    Flowers form on the flanks of the shoot apical meristem (SAM) in response to environmental and endogenous cues. In Arabidopsis (Arabidopsis thaliana), the photoperiodic pathway acts through FLOWERING LOCUS T (FT) to promote floral induction in response to day length. A complex between FT and the basic leucine-zipper transcription factor FD is proposed to form in the SAM, leading to activation of APETALA1 and LEAFY and thereby promoting floral meristem identity. We identified mutations that suppress FT function and recovered a new allele of the homeodomain transcription factor PENNYWISE (PNY). Genetic and molecular analyses showed that ectopic expression of BLADE-ON-PETIOLE1 (BOP1) and BOP2, which encode transcriptional coactivators, in the SAM during vegetative development, confers the late flowering of pny mutants. In wild-type plants, BOP1 and BOP2 are expressed in lateral organs close to boundaries of the SAM, whereas in pny mutants, their expression occurs in the SAM. This ectopic expression lowers FD mRNA levels, reducing responsiveness to FT and impairing activation of APETALA1 and LEAFY. We show that PNY binds to the promoters of BOP1 and BOP2, repressing their transcription. These results demonstrate a direct role for PNY in defining the spatial expression patterns of boundary genes and the significance of this process for floral induction by FT. PMID:26417007

  7. Estudio comparativo de la evaluación a la corrosión de recubrimientos de crn y crn/cr con recubrimientos de cromo electrodepositado y pinturas tipo epoxy

    OpenAIRE

    Torres, Magda; Chipatecua, Yuri; Marulanda Cardona, Diana Maritza; Olaya Florez, Jhon Jairo

    2010-01-01

    En este trabajo se compara la resistencia a la corrosión de recubrimientos de CrN y CrN/Cr depositados con el sistema de sputtering con magnetrón desbalanceado (UBM) con recubrimientos industriales de Cr y pinturas tipo epoxy. Los recubrimientos UBM fueron optimizados y producidos a temperatura ambiente y con una corriente de descarga de 400 mA. Se utilizó un flujo de Ar de 9 sccm y para la producción de CrN se activó el nitrógeno con un flujo de 3 sccm. Los tiempos de depósito se ajustaron p...

  8. Effect of Ag/W addition on the wear performance of CrN coatings prepared by RF unbalanced magnetron sputtering

    International Nuclear Information System (INIS)

    It has been learned that chromium nitride (CrN) performs better than titanium nitride (TiN) under some specific applications. However, the relatively low hardness of CrN still remains a problem. In this study, we tried to increase the hardness of CrN by means of addition of varying content of the third party element Ag/W. The content of Ag/W additive was varied by applying varying levels of currents to the Ag/W targets. Subsequently, a series of tests were conducted to analyze the coatings, including composition and structure analyses, scratch test, Knoop hardness test and wear test. The results showed that the CrN coatings with Ag addition did not show obvious improvement with regard to the hardness and wear performance, while coatings with W addition showed a significant enhancement. Compared with CrN, the W addition led to enhancement in hardness and wear resistance, due to the formation of tungsten nitride (WN) in the CrN coatings. At a W content of 6.8 at.%, the wear was reduced by ∼73%

  9. Growth of N-polar GaN Using a CrN buffer layer on (0001) Al2O3 via plasma-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    The growth of N-polar GaN films on (0001) Al2O3 substrates by plasma-assisted molecular beam epitaxy was demonstrated using a CrN buffer layer. Analysis of reflection high energy electron diffraction (RHEED) patterns and a chemical etching method were used in order to confirm the polarity of GaN on CrN. RHEED patterns show the 3 × 3 pattern characteristic of GaN. Chemical etching significantly changes the GaN surface morphology which implies that the N-polar GaN was grown on the CrN buffer layer. In addition, an improvement in the crystal properties of GaN was achieved using the annealing process for the CrN buffer layers. - Highlights: ► Demonstration of N-polar GaN growth on sapphire using CrN buffer layer. ► Polarity selection model proposed to explain the experimental observations. ► Improvement of N-polar GaN crystallinity with thermal treatment of CrN layers

  10. Microstructural and tribological investigations of CrN coated, wet-stripped and recoated functional substrates used for cutting and forming tools

    International Nuclear Information System (INIS)

    Recent breakthroughs in wet-stripping Physical Vapour Deposited (PVD) CrN coatings on standard high speed and stainless steels and on hard metal substrates are reported in this work. Validation of the stripping process was evaluated in terms of substrate damage after exposure to the chemical agents and also in terms of the tribological properties of the PVD CrN layers before (Pristine) and after stripping and re-coating (Recoated). The investigation was focussed on the influence of the stripping processes on the hardness, roughness, adherence and wear resistance of the Recoated CrN coatings deposited by electron beam PVD (e-beam) after stripping. Analysis of the chemically stripped and Recoated steel substrates showed that: (a) hardness and elastic modulus of the Recoated e-beam CrN did not change significantly compared to Pristine e-beam CrN, and (b) surface roughness of the Recoated e-beam CrN layers was greater by a factor of 50-60% than the initial. For hard-metal substrates, the surface damage and its effect on the re-deposited coating performance in terms of the chemical reactions during the stripping process were discussed. It was observed that wet-stripping in a basic solution led to depletion of tungsten and carbon at the surface of the stripped WC-Co specimens

  11. HrpNEa -induced deterrent effect on phloem feeding of the green peach aphid Myzus persicae requires AtGSL5 and AtMYB44 genes in Arabidopsis thaliana

    Indian Academy of Sciences (India)

    Beibei Lü; Weiwei Sun; Shuping Zhang; Chunling Zhang; Jun Qian; Xiaomeng Wang; Rong Gao; Hansong Dong

    2011-03-01

    In Arabidopsis thaliana (Arabidopsis) treated with the harpin protein HrpNEa, resistance to the green peach aphid Myzus persicae, a generalist phloem-feeding insect, develops with induced expression of the AtMYB44 gene. Special GLUCAN SYNTHESIS-LIKE (GSL) genes and -1,3-glucan callose play an important role in plant defence responses to attacks by phloem-feeding insects. Here we report that AtGLS5 and AtMYB44 are both required for HrpNEa-induced repression of M. persicae feeding from the phloem of Arabidopsis leaves. In 24 h successive surveys on large-scale aphid populations, the proportion of feeding aphids was much smaller in HrpNEa-treated plants than in control plants, and aphids preferred to feed from the 37 tested atgsl mutants rather than the wild-type plant. The atgsl mutants were generated previously by mutagenesis in 12 identified AtGSL genes (AtGSL1 through AtGSL12); in the 24 h survey, both atgsl5 and atgsl6 tolerated aphid feeding, and atgsl5 was the most tolerant. Consistently, atgsl5 was also most inhibitive to the deterrent effect of HrpNEa on the phloem-feeding activity of aphids as monitored by the electrical penetration graph technique. These results suggested an important role of the AtGSL5 gene in the effect of HrpNEa. In response to HrpNEa, AtGSL5 expression and callose deposition were induced in the wild-type plant but not in atgsl5. In response to HrpNEa, moreover, the AtMYB44 gene known to be required for repression of aphid reproduction on the plant was also required for repression of the phloem-feeding activity. Small amounts of the AtGSL5 transcript and callose deposition were detected in the atmyb44 mutant, as in atgsl5. Both mutants performed similarly in tolerating the phloem-feeding activity and impairing the deterrent effect of HrpNEa, suggesting that AtGSL5 and AtMYB44 both contributed to the effect.

  12. Regularities of Structure Formation of Coatings CrN, Obtained by Vacuum Arc Evaporation in a Nitrogen Atmosphere

    Directory of Open Access Journals (Sweden)

    O.V. Sobol'

    2015-03-01

    Full Text Available The questions of structural engineering of Cr-N system coatings produced by vacuum arc evaporation of Cr cathode in a nitrogen atmosphere are considered. As the variable physical and technological parameters we have used the following ones: pressure of nitrogen atmosphere (3.5…48×10–4 Torr and negative bias potential applied to the substrate in constant (Ub = – 120 V and pulse (Uip = – 1200 V modes. Increase in the pressure without pulse action allows to transfer from Cr + Cr2N phase to phase of textured CrN crystallites with [111] axis. The transition from the metallic phase to the mechanical nitride is accompanied by a decrease in the average size of crystallites. Additional supply of impulse capacity allows to intensify the process of formation of nitrides and stimulates formation at high pressure of radiation-resistant texture units with the [110] axis.

  13. Microstructure and Mechanical Properties of CrN Films Deposited by Inductively Coupled Plasma Enhanced Radio Frequency Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    LIU Feng; MENG Yuedong; REN Zhaoxing; SHU Xingsheng

    2008-01-01

    CrN films have been synthesized on Si(100) wafer by inductively coupled plasma (ICP)-enhanced radio frequency (RF) magnetron sputtering. The effects of ICP power on mi-crostructure, crystal orientation, nanohardness and stress of the CrN films have been investigated. With the increase of ICP power, the current density at substrate increases and the films exhibit denser structure, while the DC self-bias of target and the deposition rate of films decrease. The films change from crystal structure to amorphous structure with the increase of ICP power. The measured nanohardness and the compressive stress of films reach the topmost at ICP power of 150 W and 200 W, respectively. The mechanical properties of films show strong dependence on the crystalline structure and the density influenced by the ICP power.

  14. Effect of nitrogen flow rate on properties of CrN films Prepared by HCD-gun

    Directory of Open Access Journals (Sweden)

    A.J. Novinrooz

    2006-04-01

    Full Text Available Purpose: The effect of reactant nitrogen gas flow rate on the tribological properties of CrN thin films was studied.Design/methodology/approach: Hollow Cathode Discharge gun (HCD-gun was employed for the coating of CrN films on the glass and SS-316 sub strum. The reactant nitrogen with different flow was fed in to the vacuum chamber of 3x10-3 Pa pressure to form Cr N composite under experimental condition.Findings: The crystalline phase and micro structural studies of the specimens were carried out by XRD and SEM respectively. It was found that the preferred orientation for CrN films was (200 and that for Cr2N was (111. The micro hardness measurement fulfilled by Vickers test, and the hardness value obtained was 2100kgm-2. The glow discharge optical emission spectroscopy (GDOES was used for compositional analysis of the content elements. The wear resistance test was performed under specific condition.Research limitations/implications: We have completed our discussion by commenting the results on small deposition area, and therefore, we endeavor further attempt on large area coating.Practical implications: The Cr - N composite due to higher hardness, wear resistance and anticorrosion characteristics is widely used in cutting tools, aerospace and industrial fields.Originality/value: It may be remarked that the hardness and wear resistance values obtained in this work is very encouraging and therefore makes thin composite suitable in various technical applications.

  15. The influence of superelastic NiTi interlayers on tribological properties of CrN hard coatings

    International Nuclear Information System (INIS)

    The tribological performance of hard-coatings such as chromium nitride depends intimately on the mechanical properties of the support structure beneath the coating. For soft substrates, poor support characteristics severely degrade hard coating performance. The present work examines the potential for sputtered thin films of superelastic NiTi to improve hard-coating performance on soft substrates by limiting asperity contact stresses and mitigating the effects of compliance and thermal expansion coefficient mismatches between base metal and coating. NiTi thin films were deposited on 6061-T6 aluminum substrates using dc magnetron sputtering. CrN hard-coatings were then deposited by unbalanced reactive magnetron sputter deposition. Reversible stress-induced martensite transformations and mechanical properties of the NiTi films were investigated by temperature-controlled X-ray diffraction and nano-indentation experiments. The tribological properties of CrN coatings, with and without superelastic NiTi interlayers, were measured by ball-on-disk wear and scratch tests at different temperatures. It is shown that reversible martensite transformations in NiTi interlayers can exert a significant influence on the tribological properties of CrN coatings

  16. Análisis estructural, superficial y tribológico de recubrimientos de nitruro de cromo (CrN) sintetizado por magnetrón sputtering reactivo DC = Structural, surface and tribological analyzed of CrN thin films by reactive magnetron sputtering DC

    OpenAIRE

    RUDEN MUÑOZ, ALEXANDER

    2011-01-01

    Se sintetizaron recubrimientos duros de CrN, por la técnica de Magnetrón Sputtering Reactivo, sobre sustratos de acero AISI 304 y 4140, analizando sus propiedades estructurales, mecánicas, tribológicas y de corrosión, cuando existe variación de la presión de trabajo de 30 y 3 mTorr. A partir de XRD, se observo la formación de la fase FCC y HCP del CrN, en orientaciones preferenciales (111) y (110) respectivamente; se determino la nanodureza del recubrimiento CrN, sintetizado sobre los sustrat...

  17. Microstructure and Corrosion Behavior of Ni-Alloy/ CrN Nano layered Coatings

    International Nuclear Information System (INIS)

    The Ni-alloy/CrN nanolayered coatings, Ni-Al/CrN and Ni-P/CrN, were deposited on (100) silicon wafer and AISI 420 stainless steel substrates by dual-gun sputtering technique. The influences of the layer microstructure on corrosion behavior of the nanolayered thin films were investigated. The bilayer thickness was controlled approximately 10 nm with a total coating thickness of 1μ m. The single-layer Ni-alloy and CrN coatings deposited at 350 C were also evaluated for comparison. Through phase identification, phases of Ni-P and Ni-Al compounds were observed in the single Ni-alloy layers. On the other hand, the nanolayered Ni-P/CrN and Ni-Al/CrN coatings showed an amorphous/nanocrystalline microstructure. The precipitation of Ni-Al and Ni-P intermetallic compounds was suppressed by the nanolayered configuration of Ni-alloy/CrN coatings. Through Tafel analysis, the Ecorr and Icorr values ranged from 10.64 to 10.33 V and 1.42 x10-5 to 1.14 x10-6 A/cm2, respectively, were deduced for various coating assemblies. The corrosion mechanisms and related behaviors of the coatings were compared. The coatings with a nanolayered Ni-alloy/CrN configuration exhibited a superior corrosion resistance to single-layer alloy or nitride coatings.

  18. Comparison of land surface temperature measurements at NOAA CRN sites with airborne and satellite observations

    Science.gov (United States)

    Krishnan, P.; Kochendorfer, J.; Baker, B.; Dumas, E.; Meyers, T. P.; Guillevic, P.; Corda, S.; Muratore, J.; Martos, B.

    2011-12-01

    Land surface temperature (LST) is a key variable for studying global or regional land surface processes and the energy and water vapor exchange at the biosphere-atmosphere interface. In an effort to better quantify the spatial variability and overall representativeness of single-point surface temperature measurement being recorded at NOAA's Climate Reference Network (CRN) sites and to improve the accuracy of satellite land surface temperature measurements, airborne flight campaigns were conducted over two vegetated sites in Tennessee, USA during 2010 to 2011. During the campaign, multiple measurements of land surface temperature were made using Infra-Red temperature sensors at micrometeorological tower sites and onboard an instrumented Piper Navajo airborne research aircraft. In addition to this, coincident Moderate Resolution Imaging Spectroradiometer (MODIS) LST observations, onboard the NASA Terra and Aqua Earth Observing System satellites were used. The aircraft-based and satellite based land surface temperature measurements were compared to in situ, tower based LST measurements. Preliminary results show good agreement between in situ, aircraft and satellite measurements.

  19. CrN coatings deposited by magnetron sputtering: Mechanical and tribological properties

    Directory of Open Access Journals (Sweden)

    Alexander Ruden-Muñoz

    2015-01-01

    Full Text Available Se analizaron las propiedades mecánicas y tribológicas de recubrimientos de CrN crecidos sobre sutratos de aceros AISI 203 y AISI 4140 usando la técnica de pulverización catódica con magnetrón. Los recubrimietos fueron crecidos a dos presiones de trabajo, 0.4 y 4.0 Pa. Las películas crecidas sobre acero AISI 304 a 0.4 Pa mostraron la dureza más alta debido a que ésta presenta gran tamaño de grano y baja rugosidad. Para los recubrimientos sinterizados a o.4 Pa, el daño superficial fue bajo durante la prueba tribológica. Se realizaron estudios de adherencia, obteniéndose Lc1 y Lc2 para los recubrimietos producidos con ambas presiones y en abos sustratos. Se observó una mejor adherencia en las películas crecidas a baja presión debido a su mayor espesor (~890 nm.

  20. Arc evaporated CrN coating on steam turbine blade for erosion protection

    International Nuclear Information System (INIS)

    The erosion of steam turbine blade has been one of important problems in power generation system including nuclear power plant. It was proved that the collision of water drops in steam have brought about severe erosion problem in combination with the high rotating speed of turbine blades. current component of steam turbine blade is composite of 12 Cr steel as body and of stellite 6B as shield materials on leading edge. The erosion problem calls for the high cost of maintenance and repair as well as the safety and low efficiency of power generation. The solutions for erosion protection are generally to develop the new alloy system to combat or reduce the erosion source and to improve the surface property of steam turbine blade by coating of hard-phase materials. In this paper, coating properties of CrN and its coating process will be presented with an aim at providing the possibilities of new coating as candidate for steam turbine blade application in the practical point of anti-erosion and economy. (author)

  1. Arabidopsis AtRRP44A is the functional homolog of Rrp44/Dis3, an exosome component, is essential for viability and is required for RNA processing and degradation.

    Directory of Open Access Journals (Sweden)

    Naoyoshi Kumakura

    Full Text Available The RNA exosome is a multi-subunit complex that is responsible for 3' to 5' degradation and processing of cellular RNA. Rrp44/Dis3 is the catalytic center of the exosome in yeast and humans. However, the role of Rrp44/Dis3 homologs in plants is still unidentified. Here, we show that Arabidopsis AtRRP44A is the functional homolog of Rrp44/Dis3, is essential for plant viability and is required for RNA processing and degradation. We characterized AtRRP44A and AtRRP44B/SOV, two predicted Arabidopsis Rrp44/Dis3 homologs. AtRRP44A could functionally replace S. cerevisiae Rrp44/Dis3, but AtRRP44B/SOV could not. rrp44a knock-down mutants showed typical phenotypes of exosome function deficiency, 5.8S rRNA 3' extension and rRNA maturation by-product over-accumulation, but rrp44b mutants did not. Conversely, AtRRP44B/SOV mutants showed elevated levels of a selected mRNA, on which rrp44a did not have detectable effects. Although T-DNA insertion mutants of AtRRP44B/SOV had no obvious phenotype, those of AtRRP44A showed defects in female gametophyte development and early embryogenesis. These results indicate that AtRRP44A and AtRRP44B/SOV have independent roles for RNA turnover in plants.

  2. Catalytically-inactive beta-amylase BAM4 required for starch breakdown in Arabidopsis leaves is a starch-binding-protein.

    Science.gov (United States)

    Li, Jing; Francisco, Perigio; Zhou, Wenxu; Edner, Christoph; Steup, Martin; Ritte, Gerhard; Bond, Charles S; Smith, Steven M

    2009-09-01

    Of the four chloroplast beta-amylase (BAM) proteins identified in Arabidopsis, BAM3 and BAM4 were previously shown to play the major roles in leaf starch breakdown, although BAM4 apparently lacks key active site residues and beta-amylase activity. Here we tested multiple BAM4 proteins with different N-terminal sequences with a range of glucan substrates and assay methods, but detected no alpha-1,4-glucan hydrolase activity. BAM4 did not affect BAM1, BAM2 or BAM3 activity even when added in 10-fold excess, nor the BAM3-catalysed release of maltose from isolated starch granules in the presence of glucan water dikinase. However, BAM4 binds to amylopectin and to amylose-Sepharose whereas BAM2 has very low beta-amylase activity and poor glucan binding. The low activity of BAM2 may be explained by poor glucan binding but absence of BAM4 activity is not. These results suggest that BAM4 facilitates starch breakdown by a mechanism involving direct interaction with starch or other alpha-1,4-glucan. PMID:19664588

  3. The Arabidopsis MUM2 gene encodes a beta-galactosidase required for the production of seed coat mucilage with correct hydration properties.

    Science.gov (United States)

    Dean, Gillian H; Zheng, Huanquan; Tewari, Jagdish; Huang, Jun; Young, Diana S; Hwang, Yeen Ting; Western, Tamara L; Carpita, Nicholas C; McCann, Maureen C; Mansfield, Shawn D; Haughn, George W

    2007-12-01

    Seed coat development in Arabidopsis thaliana involves a complex pathway where cells of the outer integument differentiate into a highly specialized cell type after fertilization. One aspect of this developmental process involves the secretion of a large amount of pectinaceous mucilage into the apoplast. When the mature seed coat is exposed to water, this mucilage expands to break the primary cell wall and encapsulate the seed. The mucilage-modified2 (mum2) mutant is characterized by a failure to extrude mucilage on hydration, although mucilage is produced as normal during development. The defect in mum2 appears to reside in the mucilage itself, as mucilage fails to expand even when the barrier of the primary cell wall is removed. We have cloned the MUM2 gene and expressed recombinant MUM2 protein, which has beta-galactosidase activity. Biochemical analysis of the mum2 mucilage reveals alterations in pectins that are consistent with a defect in beta-galactosidase activity, and we have demonstrated that MUM2 is localized to the cell wall. We propose that MUM2 is involved in modifying mucilage to allow it to expand upon hydration, establishing a link between the galactosyl side-chain structure of pectin and its physical properties. PMID:18165329

  4. Gibberellins control fruit patterning in Arabidopsis thaliana.

    Science.gov (United States)

    Arnaud, Nicolas; Girin, Thomas; Sorefan, Karim; Fuentes, Sara; Wood, Thomas A; Lawrenson, Tom; Sablowski, Robert; Østergaard, Lars

    2010-10-01

    The Arabidopsis basic helix-loop-helix (bHLH) proteins INDEHISCENT (IND) and ALCATRAZ (ALC) specify tissues required for fruit opening that have major roles in seed dispersal and plant domestication. Here, we show that synthesis of the phytohormone gibberellin is a direct and necessary target of IND, and that ALC interacts directly with DELLA repressors, which antagonize ALC function but are destabilized by gibberellin. Thus, the gibberellin/DELLA pathway has a key role in patterning the Arabidopsis fruit, and the interaction between DELLA and bHLH proteins, previously shown to connect gibberellin and light responses, is a versatile regulatory module also used in tissue patterning. PMID:20889713

  5. HYDROPONIC METHOD FOR CULTURING POPULATIONS OF ARABIDOPSIS

    Science.gov (United States)

    A plant life-cycle bioassay using Arabidopsis thaliana (L.) Heynh. was developed to detect potential chemical phytotoxicity. The bioassay requires large numbers of plants to maximize the probability of detecting deleterious effect and to avoid any bias that could occur if only a ...

  6. Effects of Bias Voltage on the Structure and Mechanical Properties of Thick CrN Coatings Deposited by Mid-Frequency Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    RONG Shuangquan; HE Jun; WANG Hongjun; TIAN Canxin; GUO Liping; FU Dejun

    2009-01-01

    Thick CrN coatings were deposited on Si(111)substrates by electron source assisted mid-frequency magnetron sputtering working at 40 kHz.The deposition rate,structure'and microhardness of the coatings were strongly influenced by the negative bias voltage (Vb).The deposition rate reached 8.96μm/h at a Vb of-150 V.X-ray diffraction measurement revealed strong CrN (200)orientation for films prepared at low bias voltages.At a high bias voltage Ot Vb less than一25 V both CrN(200) and (111) were observed.Large and homogeneous grmns were observed by both atomic force microscopy and scanning electron microscopy in samples prepared under optimal conditions.The samples exhibited a fibrous microstructure for a low bias voltage and a columnar structure for Vb less than-150 V.

  7. Effects of Bias Voltage on the Structure and Mechanical Properties of Thick CrN Coatings Deposited by Mid-Frequency Magnetron Sputtering

    International Nuclear Information System (INIS)

    Thick CrN coatings were deposited on Si (111) substrates by electron source assisted mid-frequency magnetron sputtering working at 40 kHz. The deposition rate, structure, and microhardness of the coatings were strongly influenced by the negative bias voltage (Vb). The deposition rate reached 8.96 μm/h at a Vb of -150 V. X-ray diffraction measurement revealed strong CrN (200) orientation for films prepared at low bias voltages. At a high bias voltage of Vb less than -25 V both CrN (200) and (111) were observed. Large and homogeneous grains were observed by both atomic force microscopy and scanning electron microscopy in samples prepared under optimal conditions. The samples exhibited a fibrous microstructure for a low bias voltage and a columnar structure for Vb less than -150 V. (low temperature plasma)

  8. Comparison of the CrN and TiN/(Ti,Al)N PVD coatings deposited onto plasma nitrited steel

    OpenAIRE

    M. Polok-Rubiniec; L.A. Dobrzański

    2012-01-01

    Purpose: The paper presents the results of the mechanical and tribological properties of the CrN and TiN/(Ti,Al)N PVD coatings deposited onto plasma nitrided hot work tool steel X37CrMoV5-1 type.Design/methodology/approach: Tests of the coatings’ adhesion to the substrate material were made using the scratch test. The surfaces’ topography, structure of the PVD coatings were observed on the scanning electron microscopy. Wear resistance tests with the pin-on-disc method were carried out on the ...

  9. Implementation of TiAIN and CrN coatings and ion implantation in the modern plastics moulding industry

    International Nuclear Information System (INIS)

    Two methods of surface improvement widely used in the modern plastics industry are compared, with a view to improving productivity and product quality. Ion implantation of plastics and physical vapour deposition coatings both offer surface engineering advantages. Each method is described and evaluated with reference to plastics moulding. TiAIN coatings are used to protect hard bulk materials, subjected to evenly distributed loads. The more ductile CrN coatings are used for softer materials which give less support to the coatings. (UK)

  10. Electrical property measurements of Cr-N codoped TiO2 epitaxial thin films grown by pulsed laser deposition,

    OpenAIRE

    Jacimovic, Jacim; Gaal, Richard; Magrez, Arnaud; Forró, László; Regmi, Mauri; Eres, Gyula

    2013-01-01

    The temperature dependent resistivity and thermo-electric power of Cr-N codoped TiO2 were compared with that of single element N and Cr doped and undoped TiO2 using epitaxial anatase thin films grown by pulsed laser deposition on (100) LaAlO3 substrates. The resistivity plots and especially the thermoelectric power data confirm that codoping is not a simple sum of single element doping. However, the negative sign of the Seebeck coefficient indicates electron dominated transport independent of...

  11. Spectroscopic investigations of Cr, CrN and TiCr anti-multipactor coatings grown by cathodic-arc reactive evaporation

    International Nuclear Information System (INIS)

    Cr, CrN, TiCr coatings have been investigated as potential anti-multipactor coatings. The coatings were synthesized by cathodic-arc reactive evaporation in Ar-N2 atmosphere where the ion energy is controlled by substrate biasing. Chemical state analysis and surface composition were studied by X-ray photoemission spectroscopy (XPS), whereas bulk composition and depth profile were studied by glow discharge optical emission spectroscopy (GDOES). The surface morphology was studied by optical profilometry (OP) and scanning electron microscopy (SEM). The compositions of the coatings were CrN and Ti40Cr60 and they were homogeneous in depth. Surface oxidation was higher in Ti40Cr60 than in CrN. Coatings deposited at high negative bias show lower deposition rate and had lower surface roughness than those obtained at low bias. Secondary electron emission yield (SEY) was higher for CrN than for Ti40Cr60, both before and after low-energy Ar+ ion bombardment. The SEY of Ti40Cr60 (1.17 maximum) was clearly smaller than the others. The maximum yield, σ m, and the first crossover electron energy, E 1, are the most important parameters, and (E 1/σ m)1/2 is a good figure of merit. This quantity was approximately 3 eV1/2 for Cr and CrN and 4 eV1/2 for Ti40Cr. After Ar+ ion bombardment, the average value improved significantly to 8.9 eV1/2 for Cr and CrN and 10.2 eV1/2 for Ti40Cr60. The radio-frequency multipactor performance of these materials was simulated using the experimentally determined SEY parameters

  12. A comparative study of corrosion resistance in CrN and CrN/Cr coatings, electrodeposited chromium and epoxy paints

    OpenAIRE

    Magda Torres; Yuri Chipatecua; Diana Maritza Marulanda Cardona; Jhon Jairo Olaya Florez

    2010-01-01

    This work was aimed at comparing the corrosion resistance of CrN and CrN/Cr coatings deposited through unbalanced magnetron sputtering (UBM), Cr industrial coatings and epoxy paints. UBM coatings were optimised and produced at room temperature, using 400 mA discharge current. Ar and N2 flow rates were set at 9 standard cubic centimetres per minute (SCCM) and 3 SCCM, respectively. Deposition times were set to produce CrN monolayers and nanometric multilayers having 1 μm total thickness and 100...

  13. Ab initio study of the alloying effect of transition metals on structure, stability and ductility of CrN

    International Nuclear Information System (INIS)

    The alloying effect on the lattice parameters, isostructural mixing enthalpies and ductility of the ternary nitride systems Cr1−xTMxN (TM = Sc, Y; Ti, Zr, Hf; V, Nb, Ta; Mo, W) in the cubic B1 structure has been investigated using first-principles calculations. Maximum mixing enthalpy due to large lattice mismatch in Cr1−xYxN solid solution shows a strong preference for phase separation, while Cr1−xTaxN exhibits a negative mixing enthalpy in the whole compositional range with respect to cubic B1 structured CrN and TaN, thus being unlikely to decompose spinodally. The near-to-zero mixing enthalpies of Cr1−xScxN and Cr1−xVxN are ascribed to the mutually counteracted electronic and lattice mismatch effects. Additions of small amounts of V, Nb, Ta, Mo or W into CrN coatings increase its ductility. (paper)

  14. Microstructural characterizations and hardness evaluation of d.c. reactive magnetron sputtered CrN thin films on stainless steel substrate

    Indian Academy of Sciences (India)

    Hetal N Shah; Vipin Chawla; R Jayaganthan; Davinder Kaur

    2010-04-01

    Chromium nitride (CrN) thin films were deposited on stainless steel (grade: SA304) substrate by using d.c. reactive magnetron sputtering and the influence of process parameters such as substrate temperature, pressure, and power on their microstructural characteristics were investigated in the present work. The CrN films were characterized with X-ray diffraction (XRD) to reveal the formation of different phases and its texture. The films showed the (111) preferred orientation but its intensity decreased, while intensity of peak (200) increased with increase in working pressure. The mixture of CrN and Cr2N phases were identified at low working pressure and temperature. The preferred orientations of CrN thin films are strongly influenced by sputtering conditions, thickness, and the induced residual stress in the films as observed in the present work. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the morphology and surface topography of thin films, respectively. The study shows that the hardness of films strongly depends on the grain size and the film density, which are influenced by combined effect of the working pressure, temperature, and power of the sputtering process.

  15. Influence of substrate bias voltage on the microstructure and residual stress of CrN films deposited by medium frequency magnetron sputtering

    International Nuclear Information System (INIS)

    Highlights: → The pure CrN films have been successfully prepared by medium frequency magnetron sputtering. → At low substrate bias voltage (-300 V), the compressive stresses are observed in the films. → The texture of the CrN films changes from (1 1 1) to (2 0 0) with increasing substrate bias voltage. → The surface roughness firstly decreases and then increases with increasing bias voltage. - Abstract: In this study, CrN films were deposited on stainless steel and Si (1 1 1) substrates via medium frequency magnetron sputtering under a systematic variation of the substrate bias voltage. The influence of the substrate bias voltage on the structural and the mechanical properties of the films were investigated. It is observed that there are two clear regions: (1) below -300 V, and (2) above -300 V. For the former region, the (1 1 1) texture is dominated as the substrate bias voltage is increased to -200 V. The lattice parameter is smaller than that of CrN reported in the ICSD standard (4.140 A) and the as-deposited films exhibit tensile stress. Meanwhile, the surface roughness decreases and the N concentration show a slow increase. For the latter region, the (2 0 0)-oriented structure is formed. However, the lattice parameter is larger as compared with the value reported in the ICSD standard, and the surface roughness increases and the N concentration decreases obviously. In this case, the compressive stress is obtained.

  16. Scanning electrochemical microscopy study on the electrochemical behavior of CrN film formed on 304 stainless steel by magnetron sputtering

    International Nuclear Information System (INIS)

    The electrochemical behavior of CrN film formed on 304 stainless steel (304 SS) by magnetron sputtering was investigated by scanning electrochemical microscopy (SECM) in redox competition mode and X-ray photoelectron spectroscopy (XPS) in 0.2 M H3BO3 + 0.05 M Na2B4O7 (pH = 8.4) buffer solution containing 3.5 wt% NaCl. The results demonstrated that passive film could form on the surface of CrN film with the chemical compositions of Cr, Cr2O3, CrN, Cr(OH)3, and CrO3. When applied with 0.9 vs SCE/V potential, the pitting propagation sites corresponded to the high oxygen consumption region. While above stable pit, the Pt microelectrode showed an enhanced faradic current. Separated anodes and cathodes were observed in the scratch, which suggested that the dominant corrosion mechanism is pitting corrosion induced and promoted by galvanic corrosion. These results provide a more explicit description of the corrosion mechanism and processes of CrN film

  17. Requirement of the C3HC4 zinc RING finger of the Arabidopsis PEX10 for photorespiration and leaf peroxisome contact with chloroplasts

    OpenAIRE

    Schumann, Uwe; Prestele, Jakob; O'Geen, Henriette; Brueggeman, Robert; Wanner, Gerhard; Gietl, Christine

    2007-01-01

    Plant peroxisomes perform multiple vital metabolic processes including lipid mobilization in oil-storing seeds, photorespiration, and hormone biosynthesis. Peroxisome biogenesis requires the function of peroxin (PEX) proteins, including PEX10, a C3HC4 Zn RING finger peroxisomal membrane protein. Loss of function of PEX10 causes embryo lethality at the heart stage. We investigated the function of PEX10 with conditional sublethal mutants. Four T-DNA insertion lines expressing pex10 with a dysfu...

  18. CrN/AlN superlattice coatings synthesized by pulsed closed field unbalanced magnetron sputtering with different CrN layer thicknesses

    International Nuclear Information System (INIS)

    CrN/AlN superlattice coatings with different CrN layer thicknesses were prepared using a pulsed closed field unbalanced magnetron sputtering system. A decrease in the bilayer period from 12.4 to 3.0 nm and simultaneously an increase in the Al/(Cr + Al) ratio from 19.1 to 68.7 at.% were obtained in the CrN/AlN coatings when the Cr target power was decreased from 1200 to 200 W. The bilayer period and the structure of the coatings were characterized by means of low angle and high angle X-ray diffraction and transmission electron microscopy. The mechanical and tribological properties of the coatings were studied using the nanoindentation and ball-on-disc wear tests. It was found that CrN/AlN superlattice coatings synthesized in the current study exhibited a single phase face-centered cubic structure with well defined interfaces between CrN and AlN nanolayers. Decreases in the residual stress and the lattice parameter were identified with a decrease in the CrN layer thickness. The hardness of the coatings increased with a decrease in the bilayer period and the CrN layer thickness, and reached the highest value of 42 GPa at a bilayer period of 4.1 nm (CrN layer thickness of 1.5 nm, AlN layer thickness of 2.5 nm) and an Al/(Cr + Al) ratio of 59.3 at.% in the coatings. A low coefficient of friction of 0.35 and correspondingly low wear rate of 7 x 10-7 mm3N-1m-1 were also identified in this optimized CrN/AlN coating when sliding against a WC-6%Co ball.

  19. Growth of epitaxial CrN on MgO(001): Role of deposition angle on surface morphological evolution

    International Nuclear Information System (INIS)

    CrN layers, 6 to 500 nm thick, were grown on MgO(001) at 600 deg. C by ultra-high-vacuum magnetron sputter deposition in pure N2 discharges at 2.6 Pa. The deposition angle α with respect to the surface normal was varied from 0 deg. to 80 deg. in order to directly probe the effect of atomic shadowing on the surface morphological evolution. Layers grown with α 0 deg. are single crystals which develop a regular surface mound structure. At low layer thicknesses, t ≤ 25 nm, the surface mounds grow primarily vertically, due to kinetic roughening, and form square-shapes with edges along low-energy , directions. Continued growth at t ≥ 25 nm is dominated by mound-competition and coalescence which leads to a self-similar growth mode with increases in both mound height and width. Layers deposited from oblique angles α = 80 deg. also nucleate as single crystals with a cube-on-cube epitaxial relationship with the substrate. However, rough surfaces with cauliflower-type morphologies cause the nucleation of misoriented CrN grains that develop into cone-shaped grains that protrude out of the epitaxial matrix to form triangular faceted surface mounds. Atomic shadowing exacerbates the growth rate of these misoriented grains, causing a dramatic increase in the root-mean-square surface roughness, which is ∼ 16x higher for layers grown at α = 80 deg. than at α = 0 deg. The roughening follows a power-law with a roughening exponent β that increases from 0.37 ± 0.04 to 0.57 ± 0.15 as α is increased from 0 deg. to 80 deg. This increase is attributed to a transition from kinetic roughening to roughening caused by atomic shadowing effects

  20. Fluorescence-Activated Nucleolus Sorting in Arabidopsis.

    Science.gov (United States)

    Pontvianne, Frédéric; Boyer-Clavel, Myriam; Sáez-Vásquez, Julio

    2016-01-01

    Nucleolar isolation allows exhaustive characterization of the nucleolar content. Centrifugation-based protocols are not adapted to isolation of nucleoli directly from a plant tissue because of copurification of cellular debris. We describe here a method that allows the purification of nucleoli using fluorescent-activated cell sorting from Arabidopsis thaliana leaves. This approach requires the expression of a specific nucleolar protein such as fibrillarin fused to green fluorescent protein in planta. PMID:27576720

  1. What Does a Mean Really Mean? Interpreting Mainstem Detrital CRN Data in Transient Landscapes, a view from the South Fork Eel River, CA

    Science.gov (United States)

    Crosby, B. T.; Willenbring, J.; Gasparini, N. M.

    2011-12-01

    In landscapes with steady, uniform erosion rates, mainstem detrital cosmogenic radionuclide (CRN) concentrations are expected to reflect basin-wide erosion rates. In this study, we use both field and numerical experiments to provide new insight into how these rates will vary over space and time during transient landscape adjustment. Our field data come from the South Fork Eel River (SFER) in Northern California where well-aligned knickpoints and terraces along the mainstem and tributary channels define a clear boundary between an incised, actively adjusting lowland and an unadjusted relict upland landscape. This transient adjustment is most complete in the lower portion of the basin and becomes progressively less extensive upstream, consistent with an upstream propagating wave of adjustment. To test if detrital CRN erosion rates would reflect this transient adjustment, we collected 9 sand samples along the mainstem SFER at sites distributed between the headwaters and the basin outlet. CRN erosion rates increase systematically down the mainstem from 0.22 to 0.52 mm/yr. This gradual increase in erosion rate reflects the progressive dilution of relict high CRN concentrations by low CRN concentration sediment from the rapidly eroding, adjusting regions downstream. Using a simple, two member sediment mixing model, we find that CRN concentrations should decrease in a non-linear manner as the proportion of the basin in the adjusting state increases. In order to test this non-linear dilution theory, we use the mapped boundary between the relict and adjusting regions in the SFER to quantify, for each mainstem sample site, the fraction of upstream drainage area that is in a relict state. Because the adjustment is relatively immature, our samples only range from 75% to 98% relict, but fall along the predicted mixing line. Because detrital CRN erosion rate data from any field site only provides a single snapshot of contemporary erosion rates, we employ the CHILD numerical

  2. Arabidopsis in Wageningen

    OpenAIRE

    Koornneef, M

    2013-01-01

    Arabidopsis thaliana is the plant species that in the past 25 years has developed into the major model species in plant biology research. This was due to its properties such as short generation time, its small genome and its easiness to be transformed. Wageningen University has played an important role in the development of this model, based on interdisciplinary collaborations using genetics as a major tool to investigate aspects of physiology, development, plant-microbe interactions and evol...

  3. Comparative study between the electrochemical behavior of TiN, TiCxNy and CrN hard coatings by using microscopy and electrochemical techniques

    Directory of Open Access Journals (Sweden)

    L.F. Senna

    2001-01-01

    Full Text Available Hard thin TiN, TiCxNy and CrN films deposited by Physical Vapor Deposition (PVD techniques onto steel substrates were immersed in an aggressive environment and evaluated by Atomic Force Microscopy (AFM and Electrochemical Impedance Spectroscopy (EIS. The mechanical and electrochemical behavior, as well as the microstructure of TiCxNy depended directly on the contents of carbon and nitrogen in the coating. The best results were obtained with stoichiometric coatings that are presented in this work. Although a small amount of pinholes could be observed, the electrochemical performance of TiN film was poorer than the stoichiometric TiCxNy coating. However, the CrN films showed the highest initial and residual corrosion resistance values, probably due to their dense structure.

  4. Influence of ion implantation on structural and tribological properties of chromium nitride layers of non-stoichiometric composition CrN0.4

    International Nuclear Information System (INIS)

    Structural and tribological properties of nitrogen-implanted 1.4 μm thick layers of non-stoichiometric chromium nitride CrN0.4 were studied using GXRD, AES, ball-on-flat wear/friction test and microscratching test. The results of structural investigations revealed the amorphous structure of as-deposited layers and the formation of crystalline Cr2N and CrN phases after ion implantation. A significant reduction of wear was observed as a result of ion implantation; the wear reduction is similar for the all implanted samples. The surface damage caused by scratch test of the surface of ion-implanted samples is also reduced. (author)

  5. Comparative study between the electrochemical behavior of TiN, TiCxNy and CrN hard coatings by using microscopy and electrochemical techniques

    OpenAIRE

    Senna L.F.; Achete C.A.; Simão R.A.; Hirsch T.

    2001-01-01

    Hard thin TiN, TiCxNy and CrN films deposited by Physical Vapor Deposition (PVD) techniques onto steel substrates were immersed in an aggressive environment and evaluated by Atomic Force Microscopy (AFM) and Electrochemical Impedance Spectroscopy (EIS). The mechanical and electrochemical behavior, as well as the microstructure of TiCxNy depended directly on the contents of carbon and nitrogen in the coating. The best results were obtained with stoichiometric coatings that are presented in thi...

  6. Anatolian Plateau Uplift Along the Southern Central Margin from Structural Analysis, CRN Dating, and Low-Temperature Thermochronology

    Science.gov (United States)

    Schildgen, T. F.; Yildirim, C.; Strecker, M. R.; Echtler, H. P.; Copeland, P.

    2009-12-01

    Bounding flanks of orogenic plateaus are among the most sensitive features for recording the tectonic drivers for and geomorphic responses to surface uplift. Here, processes from the base of the lithosphere to the surface of the crust are integrated in the geologic record, providing key constraints for deciphering the geodynamic processes that drive orogen growth. The southern margin of the Anatolian Plateau in south central Turkey records a history of Mesozoic to recent crustal deformation. Rivers that cut through the margin record a history of fluvial response to surface uplift and episodic base level fall (e.g., the Messinian Salinity Crisis), as well as providing cross-sections through tectonic structures that accomodated uplift. The region is also replete with geologic constraints on surface uplift, such as marine sediments that cap the plateau at elevations >2 km. Our work is focused on detailed structural mapping and new age constraints in this region where few geochronologic methods have been applied. This will help to distinguish among geodynamic interpretations of uplift that hinge on precise temporal constraints on activity over wide regions. Cross-sections through sedimentary basins along the plateau flank show changing deformation styles from west to east. Regions near the Isparta Angle show pervasive faulting and folding of Miocene sediments, likely related to Miocene and post-Miocene activity on the Kirkkavak fault. Farther east, deformation of Miocene sediments is more subtle, and generally characterized by dips of sedimentary beds that gradually steepen northwards from sub-horizontal near the coast to almost 30° SW, despite broad similarities in facies and depositional environments. The few faults that cut sediments are predominantly normal and strike-slip faults with vertical offsets commonly less than a few meters. Our geochronologic approach consists of low-T thermochronology, cosmogenic radionuclide (CRN) dating, and 87Sr/86Sr stratigraphy

  7. Effect of negative bias voltage on CrN films deposited by arc ion plating. I. Macroparticles filtration and film-growth characteristics

    International Nuclear Information System (INIS)

    Chromium nitride (CrN) films were deposited on Si wafers by arc ion plating (AIP) at various negative bias voltages and several groups of N2/Ar gas flux ratios and chamber gas pressures. The authors systematically investigated the influence of negative bias voltage on the synthesis, composition, microstructure, and properties of the AIP CrN films. In this part (Part I), the investigations were mainly focused on the macroparticle distributions and film-growth characteristics. The results showed that macroparticle densities on the film surfaces decreased greatly by applying negative bias voltage, which can be affected by partial pressure of N2 and Ar gases. From the statistical analysis of the experimental results, they proposed a new hybrid mechanism of ion bombardment and electrical repulsion. Also, the growth of the AIP CrN films was greatly altered by applying negative bias voltage. By increasing the bias voltage, the film surfaces became much smoother and the films evolved from apparent columnar microstructures to an equiaxed microstructure. The impinging high-energy Cr ions accelerated by negative bias voltages were deemed the inherent reason for the evolution of growth characteristics

  8. Comparison of tribological properties of CrN, TiCN and TiAlN coatings sliding against SiC balls in water

    International Nuclear Information System (INIS)

    CrN, TiCN and TiAlN coatings were deposited on WC cemented carbide disks using enhanced cathodic arc magnetron sputtering and their topographies and structures were observed and analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The friction and wear properties of CrN, TiCN and TiAlN coatings sliding against SiC balls in water were investigated and compared synthetically using ball-on-disk tribometer. The results showed that the CrN/SiC tribopairs showed the lowest friction coefficient of 0.076, while the TiCN/SiC tribopairs displayed the highest friction coefficient of 0.264. For the CrN/SiC tribopairs the specific wear rate of CrN coatings was lowest while that of SiC balls became highest. But for the TiAlN(TiCN)/SiC tribopairs, the specific wear rate of TiAlN coatings was highest while that of SiC balls for the TiCN/SiC tribopairs became lowest. This indicated that the friction and wear behaviors of nitride coatings/SiC balls tribo-systems in water were more strongly influenced by the anti-oxidative ability of tribomaterials in water than by their mechanical properties.

  9. Characterisation of Pristine and Recoated electron beam evaporation plasma-assisted physical vapour deposition Cr-N coatings on AISI M2 steel and WC-Co substrates

    International Nuclear Information System (INIS)

    This paper is focussed on the characterisation of electron beam evaporation plasma-assisted physical vapour deposition Cr-N coatings deposited on AISI M2 steel and hardmetal (K10) substrates in two different conditions: Pristine (i.e., coated) and Recoated (i.e., stripped and recoated). Analytical methods, including X-ray diffraction (XRD), scanning electron microscopy, scratch adhesion and pin-on-disc tests were used to evaluate several coating properties. XRD analyses indicated that both Pristine and Recoated coatings consisted of a mixture of hexagonal Cr2N and cubic CrN, regardless of substrate type. For the M2 steel substrate, only small differences were found in terms of coating phases, microstructure, adhesion, friction and wear coefficients between Pristine and Recoated. Recoated on WC-Co (K10) exhibited a less dense microstructure and significant inferior adhesion compared to Pristine on WC-Co (K10). The wear coefficient of Recoated on WC-Co was 100 times higher than those exhibited by all other specimens. The results obtained confirm that the stripping process did not adversely affect the Cr-N properties when this coating was deposited onto M2 steel substrates, but it is clear from the unsatisfactory tribological performance of Recoated on WC-Co that the stripping process is unsuitable for hardmetal substrates

  10. Coupling data from U-series and 10Be CRN to evaluate soil steady-state in the Betic Cordillera

    Science.gov (United States)

    Schoonejans, Jerome; Vanacker, Veerle; Opfergelt, Sophie; Granet, Mathieu; Chabaux, François

    2015-04-01

    The regolith mantel is produced by weathering of bedrock through physical and biochemical processes. At the same time, the upper part of the regolith is eroded by gravity mass movements, water and wind erosion. Feedback's between production and erosion of soil material are important for soil development, and are essential to reach long-term steady-state in soil chemical and physical properties. Nowadays, long-term denudation rates of regolith can be quantified by using in-situ cosmogenic nuclides (CRN). If the soil thickness remains constant over sufficiently long time, soil production rates can be determined. However, the a priori assumption of long-term steady-state can be questionable in highly dynamic environments. In this study, we present analytical data from two independent isotopic techniques, in-situ cosmogenic nuclides and Uranium series disequilibrium. The disequilibrium of Uranium isotopes (238U, 234U, 230Th, 226Ra) is an alternative method that allows assessing soil formation rates through isotopic analysis of weathering products. Nine soil profiles were sampled in three different mountain ranges of the Betic Cordillera (SE Spain): Sierra Estancias, Filabres, Cabrera. All soils overly fractured mica schist and are very thin (CRN) are about the same in the Sierra Estancias and Filabres (26 ± 10 mm/ky) and increase up to 103 ± 47 mm/ky in the Sierra Cabrera. The spatial variation in soil denudation rates is in agreement with the variation in catchment-wide denudation rates presented by Bellin et al. (2014) which present the highest rates in the Sierra Cabrera (104-246mm/kyr). Moreover it roughly coincides with the pattern of long-term exhumation of the Betic Cordillera. Results from first simulations of the U-series disequilibrium model rather suggest that soil production rates are of the same order of magnitude in the Sierra Estancias and Cabrera. In the Sierra Filabres, the U-series disequilibrium in the depth profile do not respect the hypotheses of

  11. Evidence for a disease-resistance pathway in rice similar to the NPR1-mediated signaling pathway in Arabidopsis.

    OpenAIRE

    Chern, M S; Fitzgerald, H A; YADAV, R. C.; Canlas, P E; Dong, X.; Ronald, P. C.

    2001-01-01

    The Arabidopsis NPR1/NIM1 gene is a key regulator of systemic acquired resistance (SAR). Over-expression of NPR1 leads to enhanced resistance in Arabidopsis. To investigate the role of NPR1 in monocots, we over-expressed the Arabidopsis NPR1 in rice and challenged the transgenic plants with Xanthomonas oryzae pv. oryzae (Xoo), the rice bacterial blight pathogen. The transgenic plants displayed enhanced resistance to Xoo. RNA blot hybridization indicates that enhanced resistance requires expre...

  12. Oxidation resistance of TiN, CrN, TiAlN and CrAlN coatings deposited by lateral rotating cathode arc

    International Nuclear Information System (INIS)

    In this paper, four kinds of hard coatings, TiN, CrN, TiAlN and CrAlN (with Al/Ti or Al/Cr atomic ratio around 1:1), were deposited on stainless steel substrates by a lateral rotating cathode arc technique. The as-deposited coatings were annealed in ambient atmosphere at different temperatures (500-1000 oC) for 1 h. The evolution of chemical composition, microstructure, and microhardness of these coatings after annealing at different temperatures was systematically analyzed by energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and nanoindentation experiments. The oxidation behaviour and its influence on overall hardness of these four coatings were compared. It was found that the ternary TiAlN and CrAlN coatings have better oxidation resistance than their binary counterparts, TiN and CrN coatings. The Cr-based coatings (CrN and CrAlN) exhibited evidently better oxidation resistance than the Ti-based coatings (TiN and TiAlN). TiN coating started to oxidize at 500 oC. After annealing at 700 oC no N could be detected by EDX, indicating that the coating was almost fully oxidized. After annealed at 800 oC, the coating completely delaminated from the substrate. TiAlN started to oxidize at 600 oC. It was nearly fully oxidized (with little residual nitrogen detected in the coating by EDX) and partially delaminated at 1000 oC. Both CrN and CrAlN started to oxidize at 700 oC. CrN was almost fully oxidized (with little residual nitrogen detected in the coating by EDX) and partially delaminated at 900 oC. The oxidation rate of the CrAlN coating is quite slow. After annealing at 1000 oC, only about 19 at.% oxygen was detected and the coating showed no delamination. The Ti-based (TiN and TiAlN) coatings were not able to retain their hardness at higher temperatures (≥ 700 oC). On the other hand, the hardness of CrAlN was stable at a high level between 33 and 35 GPa up to an annealing temperature of 800 oC and still kept at a comparative high value of 18.7 GPa

  13. An Arabidopsis callose synthase

    DEFF Research Database (Denmark)

    Ostergaard, Lars; Petersen, Morten; Mattsson, Ole;

    2002-01-01

    unclear whether callose synthases can also produce cellulose and whether plant cellulose synthases may also produce beta-1,3-glucans. We describe here an Arabidopsis gene, AtGsl5, encoding a plasma membrane-localized protein homologous to yeast beta-1,3-glucan synthase whose expression partially......Beta-1,3-glucan polymers are major structural components of fungal cell walls, while cellulosic beta-1,4-glucan is the predominant polysaccharide in plant cell walls. Plant beta-1,3-glucan, called callose, is produced in pollen and in response to pathogen attack and wounding, but it has been...

  14. Tribological properties of CrN coatings deposited by nitro-chromizing treatment on AISI D2 steel

    Energy Technology Data Exchange (ETDEWEB)

    Durmaz, M., E-mail: mdurmaz@sakarya.edu.tr; Abakay, E.; Sen, U.; Sen, S. [Department of Metallurgical and Materials Engineering, Engineering Faculty, Sakarya University, Esentepe Campus, 54187 Sakarya (Turkey); Kilinc, B. [Department of Metallurgical and Materials Engineering, Institute of Arts and Sciences, Sakarya University, Esentepe Campus, 54187 Sakarya (Turkey)

    2015-03-30

    In this work, the wear test of uncoated and chromium nitride coated AISI D2 cold work tool steel against alumina ball realized at 0.1 m/s sliding speeds and under the loads of 2.5N, 5N and 10N. Steel samples were nitrided at 575°C for 8 h in the first step of the coating process, and then chromium nitride coating was performed thermo-reactive deposition technique (TRD) in a powder mixture consisting of ferro-chromium, ammonium chloride and alumina at 1000°C for 2 h. Nitro-chromized samples were characterized by X-Ray diffraction analysis (XRD), scanning electron microscopy (SEM), micro-hardness and ball on disk wear tests. The coating layer formed on the AISI D2 steel was compact and homogeneous. X-ray studies showed that the phase formed in the coated layer is Cr{sub 2}N. The depth of the layer was 8.15 µm. The average hardness of the layer was 2160±15 HV{sub 0.025}. For uncoated and chromium nitride materials, wear rate increased with increasing load. The results of friction coefficient and wear rate of the tested materials showed that the CrN coating presents the lowest results.

  15. Photorepair mutants of Arabidopsis

    International Nuclear Information System (INIS)

    UV radiation induces two major DNA damage products, the cyclobutane pyrimidine dimer (CPD) and, at a lower frequency, the pyrimidine (6-4) pyrimidinone dimer (6-4 product). Although Escherichia coli and Saccharomyces cerevisiae produce a CPD-specific photolyase that eliminates only this class of dimer, Arabidopsis thaliana, Drosophila melanogaster, Crotalus atrox, and Xenopus laevis have recently been shown to photoreactivate both CPDs and 6-4 products. We describe the isolation and characterization of two new classes of mutants of Arabidopsis, termed uvr2 and uvr3, that are defective in the photoreactivation of CPDs and 6-4 products, respectively. We demonstrate that the CPD photolyase mutation is genetically linked to a DNA sequence encoding a type II (metazoan) CPD photolyase. In addition, we are able to generate plants in which only CPDs or 6-4 products are photoreactivated in the nuclear genome by exposing these mutants to UV light and then allowing them to repair one or the other class of dimers. This provides us with a unique opportunity to study the biological consequences of each of these two major UV-induced photoproducts in an intact living system

  16. Galvanic Corrosion Behavior of 13Cr-N80 Steel Couples in NaCl Solution with Different Concentrations%13Cr-N80油管钢在不同浓度NaCl溶液中的电偶腐蚀行为

    Institute of Scientific and Technical Information of China (English)

    吴领; 谢发勤; 姚小飞; 吴向清

    2013-01-01

    The corrosion behavior of super 13Cr-N80 steel couples in NaCl solution with different concentrations was investigated by electrochemical method.Corrosion morphologies and products of the couple were analyzed with SEM,EDS and XRD.The results showed that,in different concentrations of NaCl solution,distinct potential difference was found between 13Cr and N80,together with different levels of galvanic corrosion.As anode,N80 was accelerated to corroded,however,13Cr was protected as cathode when coupled.The super 13Cr-N80 steel couples could not be used without protection of N80.With the increasing of concentration of NaCl solution,corrosion current density of the super 13Cr-N80 steel couples reduced as well as the reduction of corrosion degree of N80,corrosion products of which was Fe3O4.%采用电化学方法,研究了超级13Cr-N80油管钢电偶对在不同浓度NaCl溶液中的电偶腐蚀行为,采用SEM分析了电偶对中被腐蚀试样的腐蚀形貌,并利用EDS和XRD分析手段分析了其腐蚀产物.结果表明,在不同浓度NaCl溶液中,13Cr与N80之间均存在明显的电位差,13Cr与N80偶接时均发生了不同程度的电偶腐蚀,电偶对中N80作为阳极被加速腐蚀,而13Cr作为阴极得到保护,超级13Cr-N80油管钢电偶对必须对N80防护后方可偶接使用;随着NaCl溶液浓度的增大,超级13Cr-N80油管钢电偶对的电偶电流密度减小,电偶对中N80的腐蚀程度降低,且其表面的腐蚀产物主要由Fe3O4组成.

  17. Self-consuming innate immunity in Arabidopsis

    DEFF Research Database (Denmark)

    Hofius, Daniel; Mundy, John; Petersen, Morten

    2009-01-01

    . However, it has been unclear by which molecular mechanisms plants execute PCD during innate immune responses. We recently examined HR PCD in autophagy-deficient Arabidopsis knockout mutants (atg) and find that PCD conditioned by one class of plant innate immune receptors is suppressed in atg mutants....... Intriguingly, HR triggered by another class of immune receptors with different genetic requirements is not compromised, indicating that only a specific subset of immune receptors engage the autophagy pathway for HR execution. Thus, our work provides a primary example of autophagic cell death associated with...... innate immune responses in eukaryotes as well as of prodeath functions for the autophagy pathway in plants....

  18. Transgenic Arabidopsis Gene Expression System

    Science.gov (United States)

    Ferl, Robert; Paul, Anna-Lisa

    2009-01-01

    The Transgenic Arabidopsis Gene Expression System (TAGES) investigation is one in a pair of investigations that use the Advanced Biological Research System (ABRS) facility. TAGES uses Arabidopsis thaliana, thale cress, with sensor promoter-reporter gene constructs that render the plants as biomonitors (an organism used to determine the quality of the surrounding environment) of their environment using real-time nondestructive Green Fluorescent Protein (GFP) imagery and traditional postflight analyses.

  19. Estudio comparativo de la evaluación a la corrosión de recubrimientos de CrN y CrN/Cr con recubrimientos de cromo electrodepositado y pinturas tipo epoxy A comparative study of corrosion resistance in CrN and CrN/Cr coatings, electrodeposited chromium and epoxy paints

    OpenAIRE

    Olaya Florez Jhon Jairo; Marulanda Cardona Diana Maritza; Chipatecua Yuri; Torres Magda

    2010-01-01

    En este trabajo se compara la resistencia a la corrosión de recubrimientos de CrN y CrN/Cr depositados con el sistema de sputtering con magnetrón desbalanceado (UBM) con recubrimientos industriales de Cr y pinturas tipo epoxy. Los recubrimientos UBM fueron optimizados y producidos a temperatura ambiente y con una corriente de descarga de 400 mA. Se utilizó un flujo de Ar de 9 sccm y para la producción de CrN se activó el nitrógeno con un flujo de 3 sccm. Los tiempos de depósito se ajustaron p...

  20. Transcriptomic analysis of the interaction between Helianthus annuus and its obligate parasite Plasmopara halstedii shows single nucleotide polymorphisms in CRN sequences

    Directory of Open Access Journals (Sweden)

    Gouzy Jérôme

    2011-10-01

    Full Text Available Abstract Background Downy mildew in sunflowers (Helianthus annuus L. is caused by the oomycete Plasmopara halstedii (Farl. Berlese et de Toni. Despite efforts by the international community to breed mildew-resistant varieties, downy mildew remains a major threat to the sunflower crop. Very few genomic, genetic and molecular resources are currently available to study this pathogen. Using a 454 sequencing method, expressed sequence tags (EST during the interaction between H. annuus and P. halstedii have been generated and a search was performed for sites in putative effectors to show polymorphisms between the different races of P. halstedii. Results A 454 pyrosequencing run of two infected sunflower samples (inbred lines XRQ and PSC8 infected with race 710 of P. halstedii, which exhibit incompatible and compatible interactions, respectively generated 113,720 and 172,107 useable reads. From these reads, 44,948 contigs and singletons have been produced. A bioinformatic portal, HP, was specifically created for in-depth analysis of these clusters. Using in silico filtering, 405 clusters were defined as being specific to oomycetes, and 172 were defined as non-specific oomycete clusters. A subset of these two categories was checked using PCR amplification, and 86% of the tested clusters were validated. Twenty putative RXLR and CRN effectors were detected using PSI-BLAST. Using corresponding sequences from four races (100, 304, 703 and 710, 22 SNPs were detected, providing new information on pathogen polymorphisms. Conclusions This study identified a large number of genes that are expressed during H. annuus/P. halstedii compatible or incompatible interactions. It also reveals, for the first time, that an infection mechanism exists in P. halstedii similar to that in other oomycetes associated with the presence of putative RXLR and CRN effectors. SNPs discovered in CRN effector sequences were used to determine the genetic distances between the four races

  1. Comparative studies on the thermal stability and corrosion resistance of CrN, CrSiN, and CrSiN/AlN coatings

    International Nuclear Information System (INIS)

    In this work, three kinds of Cr-based nitride coatings such as monolithic CrN, CrSiN coatings, and multilayered CrSiN/AlN coating with bilayer period of 3.0 nm were deposited on both Si (100) wafer and AISI H13 steel substrates by unbalanced magnetron sputtering. Thermal stability of these coatings was evaluated by annealing the coatings at temperatures between 600 and 1000 degree sign C for 30 min in air. In addition, the corrosion behaviors of these coatings were investigated by potentiodynamic polarization tests in a deaerated 3.5 wt. % NaCl solution at 40 degree sign C. Results from annealing test show the monolithic CrN and CrSiN coatings were completely oxidized after annealed at 800 and 900 degree sign C, and their cross sectional images and atomic force microscopy showed a loose and very porous morphology due to the oxidation. Also, the hardness values of the monolithic CrN and CrSiN coatings were decreased significantly from 22 and 27 GPa to 8 and 14 GPa, respectively. However, the multilayered CrSiN/AlN coating still exhibited a dense microstructure without visible change after annealed at 1000 degree sign C, and moreover, the relatively high hardness of 25 GPa was maintained. The superior thermal stability of the CrSiN/AlN multilayer coating could be attributed to the formation of the dense and stable oxidation barrier consisted of the Al2O3, Cr2O3, and amorphous SiO2 phases near the surface region, which retard the diffusion of oxygen into the coating. In the potentiodynamic polarization test results, it was found that the significantly improved corrosion resistance of the multilayered CrSiN/AlN coating was observed in comparison with those from the monolithic CrN and CrSiN coatings, and its corrosion current density (icorr) and protective efficiency were measured to be approximately 4.21 μA/cm2 and 95%, respectively.

  2. Microstructure and Corrosion Resistance of CrN and CrN/TiN Coated Heat-Resistant Steels in Molten Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    LinCS; PengH

    2001-01-01

    The components of the equipment for processing the Al melts into the molded parts can be markedly corroded by the molten Al. In this study, a 4 μm CrN coating or CrN/TiN multilayer coating for providing the physical and chemical barriers between the molten reactive Al and the steel substrate were deposited by Cathodic Arc Evaporation onto 10 mm-thick heat-resistant steel plates. The dipping tests were conducted in a 700℃ A356 melt for 1 to 21 h at intervals of 3 h. The damage of the coated steel was eva...

  3. Application of multireflection grazing incidence method for stress measurements in polished Al–Mg alloy and CrN coating

    OpenAIRE

    MARCISZKO, Marianna; BACZMANSKI, A; Wierzbanowski, K.; WRÓBEL, M; Braham, Chedly; CHOPART, J.-P.; LODINI, A; BONARSKI, J; TARKOWSKI, L.; ZAZI, N

    2012-01-01

    Multi-reflection grazing incidence geometry, referred to as MGIXD, characterized by a small and constant incidence angle, was applied to measure low surface stresses in very thin layers of Al-Mg alloy and CrN coating. These two materials were selected in order to deal with the low and high levels of residual stress, respectively. The influence of different mechanical treatments on residual stresses was studied for Al-Mg samples. It was found that both rolling and mechanical polishing influence t...

  4. Resistencia a la corrosión de recubrimientos de CrN depositados por PVD con UBM: tecnología eficiente y ambientalmente limpia

    OpenAIRE

    John Jairo Olaya; Ulises Piratoba; Sandra Elizabeth Rodil

    2011-01-01

    En este trabajo, se estudia la influencia de la configuración del campo magnético sobre la resistencia a la corrosión de recubrimientos de CrN, obtenidos en un sistema de sputtering con magnetrón desbalanceado (MDB). Las diferentes configuraciones del campo magnético se cuantificaron a través del coeficiente geométrico de desbalance K G. La morfología transversal se determinó con microscopia electrónica de barrido (MEB) y las fases cristalinas y orientación preferencial con difracción de rayo...

  5. The Structure and Properties of Inductively Coupled Plasma Assisted Magnetron Sputtered Nanocrystalline CrN Coatings in Corrosion Protective Die Casting Molds.

    Science.gov (United States)

    Chun, Sung-Yong

    2015-07-01

    Chromium nitride coatings for the surface modified die casting molds with various ICP powers have been prepared using ICP assisted magnetron sputtering. The applied ICP power was varied from 0 to 300 W. The deposited coatings were characterized post-deposition using X-ray diffractometry (XRD) and atomic force microscopy (AFM). Single CrN phased coatings with nano-grain sized (< 20 nm) were identified. The corrosion resistance and hardness of each coating were evaluated from potentiost at and nanoindentator. Superior corrosion protective coatings in excess of 20 GPa were deposited with assistance of ICP plasma during sputtering. PMID:26373141

  6. X-ray photoelectron spectroscopy study on the CrN surface grown on sapphire substrate to control the polarity of ZnO by plasma-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    We have studied on the polarity selection procedure of ZnO grown on CrN buffer by using X-ray photoelectron spectroscopy (XPS). XPS studies have been performed on the O- and Zn-treated CrN/Al2O3surfaces and revealed that Cr2O3 and Zn-chromate-like structures are formed on O- and Zn-treated CrN surfaces, respectively. The polarity selection procedure is explained in terms of the variation of bonding coordination by the formation of ZnO on the topmost O- and Zn-atoms of each surface.

  7. Rhamnolipids elicit defense responses and induce disease resistance against biotrophic, hemibiotrophic, and necrotrophic pathogens that require different signaling pathways in Arabidopsis and highlight a central role for salicylic acid.

    Science.gov (United States)

    Sanchez, Lisa; Courteaux, Barbara; Hubert, Jane; Kauffmann, Serge; Renault, Jean-Hugues; Clément, Christophe; Baillieul, Fabienne; Dorey, Stéphan

    2012-11-01

    Plant resistance to phytopathogenic microorganisms mainly relies on the activation of an innate immune response usually launched after recognition by the plant cells of microbe-associated molecular patterns. The plant hormones, salicylic acid (SA), jasmonic acid, and ethylene have emerged as key players in the signaling networks involved in plant immunity. Rhamnolipids (RLs) are glycolipids produced by bacteria and are involved in surface motility and biofilm development. Here we report that RLs trigger an immune response in Arabidopsis (Arabidopsis thaliana) characterized by signaling molecules accumulation and defense gene activation. This immune response participates to resistance against the hemibiotrophic bacterium Pseudomonas syringae pv tomato, the biotrophic oomycete Hyaloperonospora arabidopsidis, and the necrotrophic fungus Botrytis cinerea. We show that RL-mediated resistance involves different signaling pathways that depend on the type of pathogen. Ethylene is involved in RL-induced resistance to H. arabidopsidis and to P. syringae pv tomato whereas jasmonic acid is essential for the resistance to B. cinerea. SA participates to the restriction of all pathogens. We also show evidence that SA-dependent plant defenses are potentiated by RLs following challenge by B. cinerea or P. syringae pv tomato. These results highlight a central role for SA in RL-mediated resistance. In addition to the activation of plant defense responses, antimicrobial properties of RLs are thought to participate in the protection against the fungus and the oomycete. Our data highlight the intricate mechanisms involved in plant protection triggered by a new type of molecule that can be perceived by plant cells and that can also act directly onto pathogens. PMID:22968829

  8. Estudio comparativo de la evaluación a la corrosión de recubrimientos de CrN y CrN/Cr con recubrimientos de cromo electrodepositado y pinturas tipo epoxy A comparative study of corrosion resistance in CrN and CrN/Cr coatings, electrodeposited chromium and epoxy paints

    Directory of Open Access Journals (Sweden)

    Olaya Florez Jhon Jairo

    2010-12-01

    Full Text Available En este trabajo se compara la resistencia a la corrosión de recubrimientos de CrN y CrN/Cr depositados con el sistema de sputtering con magnetrón desbalanceado (UBM con recubrimientos industriales de Cr y pinturas tipo epoxy. Los recubrimientos UBM fueron optimizados y producidos a temperatura ambiente y con una corriente de descarga de 400 mA. Se utilizó un flujo de Ar de 9 sccm y para la producción de CrN se activó el nitrógeno con un flujo de 3 sccm. Los tiempos de depósito se ajustaron para producir monocapas de CrN y multicapas a escala nanométrica manteniendo un espesor total de 1 μm y un periodo de 100 nm. A los recubrimientos obtenidos se les determinó su microestructura con icroscopia electrónica de barrido (SEM, la textura y fases cristalinas con difracción de rayos X (XRD y espectroscopia infrarroja (IR, y la resistencia a la corrosión se evaluó con ensayos de polarización potenciodinámica utilizando una solución de 0,5M H2SO4 y 0,05M KSCN. En general, las multicapas anométricas mejoraron la resistencia a la corrosión de los aceros inoxidables, además se observó que los aceros A36 recubiertos con CrN pueden ser una alternativa para reemplazar a los aceros inoxidables en ambientes ácidos.Los mecanismos de corrosión para los recubrimientos producidos son discutidos en esta investigación.This work was aimed at comparing the corrosion resistance of CrN and CrN/Cr coatings deposited through unbalanced magnetron sputtering (UBM, Cr industrial coatings and epoxy paints. UBM coatings were optimised and produced at room temperature, using 400 mA discharge current. Ar and N2 flow rates were set at 9 standard cubic centimetres per minute (SCCM and 3 SCCM, respectively. Deposition times were set to produce CrN monolayers and nanometric multilayers having 1 μm total thickness and 100 nm period. Coating icrostructure was determined through scanning electron microscopy as texture and crystalline phases were determined using

  9. Improved Corrosion Resistance and Mechanical Properties of CrN Hard Coatings with an Atomic Layer Deposited Al2O3 Interlayer.

    Science.gov (United States)

    Wan, Zhixin; Zhang, Teng Fei; Lee, Han-Bo-Ram; Yang, Ji Hoon; Choi, Woo Chang; Han, Byungchan; Kim, Kwang Ho; Kwon, Se-Hun

    2015-12-01

    A new approach was adopted to improve the corrosion resistance of CrN hard coatings by inserting a Al2O3 layer through atomic layer deposition. The influence of the addition of a Al2O3 interlayer, its thickness, and the position of its insertion on the microstructure, surface roughness, corrosion behavior, and mechanical properties of the coatings was investigated. The results indicated that addition of a dense atomic layer deposited Al2O3 interlayer led to a significant decrease in the average grain size and surface roughness and to greatly improved corrosion resistance and corrosion durability of CrN coatings while maintaining their mechanical properties. Increasing the thickness of the Al2O3 interlayer and altering its insertion position so that it was near the surface of the coating also resulted in superior performance of the coating. The mechanism of this effect can be explained by the dense Al2O3 interlayer acting as a good sealing layer that inhibits charge transfer, diffusion of corrosive substances, and dislocation motion. PMID:26554497

  10. The Friction and Wear Properties of CrN, Graphit-iC and Dymon-iC Coatings in Air and under Oil-lubrication.

    Institute of Scientific and Technical Information of China (English)

    J.Stallard; S.Yang; D.G,Teer

    2004-01-01

    Hard ceramic coatings such as TiN and CrN are very successful and are widely used in improving the performance of cutting and forming tools, but they are less successful in providing protection for general machine components, such as gears and engine parts. The development of low-friction wear resistant coatings that can run dry or in a minimum amount of oil is becoming increasingly important to this industry. Two recently developed carbon-based coatings Graphit-iCTM and Dymon-iC, which are shown to exhibit very high sliding wear resistance and low friction in dry conditions, are compared to a CrN coating under oil lubricated conditions. Long term pin-on-disc tests using a chrome steel counterface ball were carried out on coated HSS test samples. All the coatings performed well at very high applied contact pressures, exceeding 1.5 GPa, but the Graphit-iCTM and Dymon-iC coatings also exhibited the desirable characteristic of protecting the counterface material. Reasons for this behaviour are discussed.

  11. Arabidopsis Growth Simulation Using Image Processing Technology

    Directory of Open Access Journals (Sweden)

    Junmei Zhang

    2014-01-01

    Full Text Available This paper aims to provide a method to represent the virtual Arabidopsis plant at each growth stage. It includes simulating the shape and providing growth parameters. The shape is described with elliptic Fourier descriptors. First, the plant is segmented from the background with the chromatic coordinates. With the segmentation result, the outer boundary series are obtained by using boundary tracking algorithm. The elliptic Fourier analysis is then carried out to extract the coefficients of the contour. The coefficients require less storage than the original contour points and can be used to simulate the shape of the plant. The growth parameters include total area and the number of leaves of the plant. The total area is obtained with the number of the plant pixels and the image calibration result. The number of leaves is derived by detecting the apex of each leaf. It is achieved by using wavelet transform to identify the local maximum of the distance signal between the contour points and the region centroid. Experiment result shows that this method can record the growth stage of Arabidopsis plant with fewer data and provide a visual platform for plant growth research.

  12. A comparison of the wear and fatigue properties of plasma-assisted physical vapour deposition TiN, CrN and duplex coatings on Ti-6Al-4V

    International Nuclear Information System (INIS)

    The study sets out to establish a comparison between duplex systems of plasma nitriding followed by plasma-assisted physical vapour deposition (PAPVD) of TiN deposited on Ti-6Al-4V, compared with PAPVD of TiN and CrN alone. The fatigue resistance has also been examined since conventional surface modifications can often impair fatigue resistance. A rubber-wheel-type abrasion tester and pin-on-disc sliding wear tester were used to examine the wear resistance of the coatings and the load-bearing capacity of the substrate respectively. A Wohler-type rotating tester was used to study the fatigue properties. Using smooth rotating-bending fatigue specimens tested in air at 5700 rev min-1 for 106 cycles or until failure it was found that TiN, CrN and the duplex coating did not impair fatigue resistance but actually improved the S-N curves and increased the endurance limit. From the wear results it was found that, although TiN and CrN do improve the wear resistance of Ti-6Al-4V significantly, it is the duplex coating that has much the greater load-bearing capacity on the titanium substrate and gives a significant improvement on PAPVD TiN or CrN coatings in sliding and abrasive wear conditions. (orig.)

  13. CRN: 1987 Progress Report

    International Nuclear Information System (INIS)

    In the Nuclear Research Center activity report, the research works effected in each of the following departments are shown: Nuclear Physics: theoretical and experimental Nuclear Physics Works, technical studies, accomplishments and applications, the Vivitron, publications, conferences and diplomas. High Energies: theoretical and experimental Physics, the LEP-DELPHI project, the NA36 experiment (strange baryons and antibaryons production in relativistic ions collisions), technical developments, publications, conferences and diplomas. Radiation Chemistry and Physics (research reports are separated in six sections): (1) Molecular and Atomic Physics and Physical Chemistry, where the main subjects are Molecular Physics, matter-radiation interactions, positon and positronium chemistry and radiochemistry; (2) Materials Science and condensed matter studies, in which the main topics are the materials elaboration and characterization, Mossbauer spectroscopy and defect implantations; (3) Analysis and instrumentation describing short time applied Optics and sensors; (4) The nuclear reactor service with neutron activation analysis and short life radioisotopes; (5) Publications, communications, conferences, thesis and researchers' stay; (6) Technology transfers concerning accelerators, dosimetry and aliments ionization

  14. CRN: 1986 progress report

    International Nuclear Information System (INIS)

    Departments activities in high energy physics, nuclear physics, radiation physics and chemistry are reported. Collaboration with university led to creation of SRNU (Service du Reacteur Nucleaire). Vivitron studies are presented

  15. Arabidopsis MAP kinase 4 negatively regulates systemic acquired resistance

    DEFF Research Database (Denmark)

    Petersen, M.; Brodersen, P.; Naested, H.;

    2000-01-01

    Transposon inactivation of Arabidopsis MAP kinase 4 produced the mpk4 mutant exhibiting constitutive systemic acquired resistance (SAR) including elevated salicylic acid (SA) revels, increased resistance to virulent pathogens, and constitutive pathogenesis-related gene expression shown by Northern...... of NPR1. PDF1.2 and THI2.1 gene induction by jasmonate was blocked in mpk4 expressing NahG, suggesting that MPK4 is required for jasmonic acid-responsive gene expression....

  16. Arabidopsis map kinase 4 negatively regulates systemic acquired resistance

    DEFF Research Database (Denmark)

    Brodersen, P; Johansen, Bo; Petersen, M;

    2000-01-01

    Transposon inactivation of Arabidopsis MAP kinase 4 produced the mpk4 mutant exhibiting constitutive systemic acquired resistance (SAR) including elevated salicylic acid (SA) levels, increased resistance to virulent pathogens, and constitutive pathogenesis-related gene expression shown by Northern...... of NPR1. PDF1.2 and THI2.1 gene induction by jasmonate was blocked in mpk4 expressing NahG, suggesting that MPK4 is required for jasmonic acid-responsive gene expression....

  17. Genetic Analyses of Meiotic Recombination in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Meiosis is essential for sexual reproduction and recombination is a critical step required for normal meiosis. Understanding the underlying molecular mechanisms that regulate recombination ie important for medical, agricultural and ecological reasons. Readily available molecular and cytological tools make Arabidopsis an excellent system to study meiosis. Here we review recent developments in molecular genetic analyses on meiotic recombination. These Include studies on plant homologs of yeast and animal genes, as well as novel genes that were first identified in plants. The characterizations of these genes have demonstrated essential functions from the initiation of recombination by double-strand breaks to repair of such breaks, from the formation of double-Holliday junctions to possible resolution of these junctions, both of which are critical for crossover formation. The recent advances have ushered a new era in plant meiosis, in which the combination of genetics, genomics, and molecular cytology can uncover important gene functions.

  18. ESTUDIO DE LA SINERGIA CORROSIÓN-EROSIÓN DE RECUBRIMIENTOS DUROS DE TiN Y CrN OBTENIDOS SOBRE ACERO AISI 1045

    OpenAIRE

    HARVEY PAYÁN; WILLIAM APERADOR; ALEJANDRO VARGAS

    2008-01-01

    En este trabajo se presentan los resultados del estudio de los efectos sinergeticos de la corrosión-erosión en recubrimientos duros de TiN y CrN obtenidos sobre acero AISI 1045 por medio de la técnica de pulverización catódica con magnetrón y se hace una comparación con los resultados mostrados por un acero inoxidable comercial AISI 316 y el acero AISI 1045 sin recubrimiento. El proceso de deposición física de vapor (Physical Vapor Deposition), contribuye ampliamente a la aplicación de pelícu...

  19. Functional analysis of the Hikeshi-like protein and its interaction with HSP70 in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Koizumi, Shinya; Ohama, Naohiko; Mizoi, Junya [Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan); Shinozaki, Kazuo [RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa 230-0045 (Japan); Yamaguchi-Shinozaki, Kazuko, E-mail: akys@mail.ecc.u-tokyo.ac.jp [Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan)

    2014-07-18

    Highlights: • HKL, a Hikeshi homologous gene is identified in Arabidopsis. • HKL interacts with two HSP70 isoforms and regulates the subcellular localization of HSC70-1. • The two HSP70 translocate into nucleus in response to heat stress. • Overexpression of HKL confers thermotolerance in transgenic plants. - Abstract: Heat shock proteins (HSPs) refold damaged proteins and are an essential component of the heat shock response. Previously, the 70 kDa heat shock protein (HSP70) has been reported to translocate into the nucleus in a heat-dependent manner in many organisms. In humans, the heat-induced translocation of HSP70 requires the nuclear carrier protein Hikeshi. In the Arabidopsis genome, only one gene encodes a protein with high homology to Hikeshi, and we named this homolog Hikeshi-like (HKL) protein. In this study, we show that two Arabidopsis HSP70 isoforms accumulate in the nucleus in response to heat shock and that HKL interacts with these HSP70s. Our histochemical analysis revealed that HKL is predominantly expressed in meristematic tissues, suggesting the potential importance of HKL during cell division in Arabidopsis. In addition, we show that HKL regulates HSP70 localization, and HKL overexpression conferred thermotolerance to transgenic Arabidopsis plants. Our results suggest that HKL plays a positive role in the thermotolerance of Arabidopsis plants and cooperatively interacts with HSP70.

  20. Evolution of NIN-like proteins in Arabidopsis, rice, and Lotus japonicus.

    Science.gov (United States)

    Schauser, Leif; Wieloch, Wioletta; Stougaard, Jens

    2005-02-01

    Genetic studies in Lotus japonicus and pea have identified Nin as a core symbiotic gene required for establishing symbiosis between legumes and nitrogen fixing bacteria collectively called Rhizobium. Sequencing of additional Lotus cDNAs combined with analysis of genome sequences from Arabidopsis and rice reveals that Nin homologues in all three species constitute small gene families. In total, the Arabidopsis and rice genomes encode nine and three NIN-like proteins (NLPs), respectively. We present here a bioinformatics analysis and prediction of NLP evolution. On a genome scale we show that in Arabidopsis, this family has evolved through segmental duplication rather than through tandem amplification. Alignment of all predicted NLP protein sequences shows a composition with six conserved modules. In addition, Lotus and pea NLPs contain segments that might characterize NIN proteins of legumes and be of importance for their function in symbiosis. The most conserved region in NLPs, the RWP-RK domain, has secondary structure predictions consistent with DNA binding properties. This motif is shared by several other small proteins in both Arabidopsis and rice. In rice, the RWP-RK domain sequences have diversified significantly more than in Arabidopsis. Database searches reveal that, apart from its presence in Arabidopsis and rice, the motif is also found in the algae Chlamydomonas and in the slime mold Dictyostelium discoideum. Thus, the origin of this putative DNA binding region seems to predate the fungus-plant divide. PMID:15785851

  1. Arabidopsis thaliana—Aphid Interaction

    OpenAIRE

    Louis, Joe; Singh, Vijay,; Shah, Jyoti

    2012-01-01

    Aphids are important pests of plants that use their stylets to tap into the sieve elements to consume phloem sap. Besides the removal of photosynthates, aphid infestation also alters source-sink patterns. Most aphids also vector viral diseases. In this chapter, we will summarize on recent significant findings in plant-aphid interaction, and how studies involving Arabidopsis thaliana and Myzus persicae (Sülzer), more commonly known as the green peach aphid (GPA), are beginning to provide impor...

  2. Selenium Speciation in Arabidopsis Thaliana

    OpenAIRE

    Wang, Xiaoou

    2011-01-01

    Selenium has been proved as an essential micronutrient and is beneficial to animals and humans. It is a structural component of the important antioxidant enzyme, glutathione peroxidase, which catalyzes reactions to detoxify reactive oxygen species. However, the essentiality of Se in plants remains controversial and the protective role of Se in plants has rarely been investigated. In this study, Arabidopsis thaliana was grown in controlled environments having selenate or selenite enriched medi...

  3. Stem cell organization in Arabidopsis

    OpenAIRE

    Wendrich, J.R.

    2016-01-01

    Growth of plant tissues and organs depends on continuous production of new cells, by niches of stem cells. Stem cells typically divide to give rise to one differentiating daughter and one non-differentiating daughter. This constant process of self-renewal ensures that the niches of stem cells or meristems stay active throughout plant-life. Specification of stem cells occurs very early during development of the emrbyo and they are maintained during later stages. The Arabidopsis embryo is a hig...

  4. Effective mutagenesis of Arabidopsis by heavy ion beam-irradiation

    International Nuclear Information System (INIS)

    Full text: Arabidopsis researches frequently include the genetic approach, so efficient, convenient, and safe methods for mutagenesis are required. Currently, the most popular method for in house mutagenesis is application of EMS. Although this method is very effective, its base substitution-type mutations often gives leaky mutants with residual gene functions, leading some difficulty in understanding the corresponding gene functions. Heavy ion beam generated by accelerators gives highest energy transfer rates among known radiation-based mutagenesis methods including X ray, gamma ray, fast neutron, electron and proton irradiation. This feature is thought to give high frequency of the double strand break of genomic DNA and resultant short deletions, resulting frame shift-type mutations. At RIKEN Accelerator Research Facility (RARF, http://www.rarf.riken.go.jp/index-e.html), we have optimized conditions for effective mutagenesis of Arabidopsis regarding to ion species and irradiation dose, and achieved comparable mutation rates to the method with EMS. (author)

  5. G2 Checkpoint Responses in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Britt, Anne

    2013-03-18

    This project focused on the mechanism and biological significance of the G2 arrest response to replication stress in plants. We employed both forward and reverse genetic approaches to identify genes required for this response. A total of 3 different postdocs, 5 undergraduates, and 2 graduate students participated in the project. We identified several genes required for damage response in plants, including homologs of genes previously identified in animals (ATM and ATR), novel, a plant-specific genes (SOG1) and a gene known in animals but previously thought to be missing from the Arabidopsis genome (ATRIP). We characterized the transcriptome of gamma-irradiated plants, and found that plants, unlike animals, express a robust transcriptional response to damage, involving genes that regulate the cell cycle and DNA metabolism. This response requires both ATM and the transcription factor SOG1. We found that both ATM and ATR play a role in meiosis in plants. We also found that plants have a cell-type-specific programmed cell death response to ionizing radiation and UV light, and that this response requires ATR, ATM, and SOG1. These results were published in a series of 5 papers.

  6. An International Bioinformatics Infrastructure to Underpin the Arabidopsis Community

    Science.gov (United States)

    The future bioinformatics needs of the Arabidopsis community as well as those of other scientific communities that depend on Arabidopsis resources were discussed at a pair of recent meetings held by the Multinational Arabidopsis Steering Committee (MASC) and the North American Arabidopsis Steering C...

  7. Arabidopsis CDS blastp result: AK106750 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK106750 002-115-C09 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylu ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  8. Arabidopsis CDS blastp result: AK104851 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK104851 001-043-A10 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylu ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  9. Arabidopsis CDS blastp result: AK100909 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK100909 J023132G24 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylul ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  10. Arabidopsis CDS blastp result: AK058950 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK058950 001-020-A07 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylu ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  11. Arabidopsis CDS blastp result: AK059821 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK059821 006-205-D11 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylu ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  12. Arabidopsis CDS blastp result: AK064944 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK064944 J013000P14 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylul ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  13. Arabidopsis CDS blastp result: AK068400 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK068400 J013151M04 At3g45810.1 ferric reductase-like transmembrane component family protein sim ... ilar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ... EMBL:AF055357 [gi:3242789], similar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ...

  14. Arabidopsis CDS blastp result: AK066013 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK066013 J013047I12 At3g45810.1 ferric reductase-like transmembrane component family protein sim ... ilar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ... EMBL:AF055357 [gi:3242789], similar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ...

  15. Arabidopsis CDS blastp result: AK100241 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK100241 J023054P13 At3g45810.1 ferric reductase-like transmembrane component family protein sim ... ilar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ... EMBL:AF055357 [gi:3242789], similar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ...

  16. Arabidopsis CDS blastp result: AK318553 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK318553 J075145A22 At3g45810.1 68416.m04958 ferric reductase-like transmembrane component famil ... y protein similar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ... EMBL:AF055357 [gi:3242789], similar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ...

  17. Using "Arabidopsis" Genetic Sequences to Teach Bioinformatics

    Science.gov (United States)

    Zhang, Xiaorong

    2009-01-01

    This article describes a new approach to teaching bioinformatics using "Arabidopsis" genetic sequences. Several open-ended and inquiry-based laboratory exercises have been designed to help students grasp key concepts and gain practical skills in bioinformatics, using "Arabidopsis" leucine-rich repeat receptor-like kinase (LRR RLK) genetic…

  18. Insight into the early steps of root hair formation revealed by the procuste1 cellulose synthase mutant of Arabidopsis thaliana

    OpenAIRE

    Singh Manoj; Fischer Urs; Singh Sunil K; Grebe Markus; Marchant Alan

    2008-01-01

    Abstract Background Formation of plant root hairs originating from epidermal cells involves selection of a polar initiation site and production of an initial hair bulge which requires local cell wall loosening. In Arabidopsis the polar initiation site is located towards the basal end of epidermal cells. However little is currently understood about the mechanism for the selection of the hair initiation site or the mechanism by which localised hair outgrowth is achieved. The Arabidopsis procust...

  19. Allele-specific virulence attenuation of the Pseudomonas syringae HopZ1a type III effector via the Arabidopsis ZAR1 resistance protein.

    Directory of Open Access Journals (Sweden)

    Jennifer D Lewis

    2010-04-01

    Full Text Available Plant resistance (R proteins provide a robust surveillance system to defend against potential pathogens. Despite their importance in plant innate immunity, relatively few of the approximately 170 R proteins in Arabidopsis have well-characterized resistance specificity. In order to identify the R protein responsible for recognition of the Pseudomonas syringae type III secreted effector (T3SE HopZ1a, we assembled an Arabidopsis R gene T-DNA Insertion Collection (ARTIC from publicly available Arabidopsis thaliana insertion lines and screened it for plants lacking HopZ1a-induced immunity. This reverse genetic screen revealed that the Arabidopsis R protein HOPZ-activated resistance 1 (ZAR1; At3g50950 is required for recognition of HopZ1a in Arabidopsis. ZAR1 belongs to the coiled-coil (CC class of nucleotide binding site and leucine-rich repeat (NBS-LRR containing R proteins; however, the ZAR1 CC domain phylogenetically clusters in a clade distinct from other related Arabidopsis R proteins. ZAR1-mediated immunity is independent of several genes required by other R protein signaling pathways, including NDR1 and RAR1, suggesting that ZAR1 possesses distinct signaling requirements. The closely-related T3SE protein, HopZ1b, is still recognized by zar1 Arabidopsis plants indicating that Arabidopsis has evolved at least two independent R proteins to recognize the HopZ T3SE family. Also, in Arabidopsis zar1 plants HopZ1a promotes P. syringae growth indicative of an ancestral virulence function for this T3SE prior to the evolution of recognition by the host resistance protein ZAR1. Our results demonstrate that the Arabidopsis resistance protein ZAR1 confers allele-specific recognition and virulence attenuation of the Pseudomonas syringae T3SE protein HopZ1a.

  20. NMR studies on 15N-labeled creatine (CR), creatinine (CRN), phosphocreatine (PCR), and phosphocreatinine (PCRN), and on barriers to rotation in creatine kinase-bound creatine in the enzymatic reaction

    International Nuclear Information System (INIS)

    Recently, the authors have synthesized 15N-2-Cr, 15N-3-Crn, 15N-2-Crn, 15N-3-PCrn, 15N-3-PCr, and 15N-2-PCr. 1H, 15N, 31P NMR data show that Crn protonates exclusively at the non-methylated ring nitrogen, confirm that PCrn is phosphorylated at the exocyclic nitrogen, and demonstrate that the 31P-15N one-bond coupling constant in 15N-3-PCr is 18 Hz, not 3 Hz as previously reported by Brindle, K.M., Porteous, R. and Radda, G.K.. The authors have found that creatine kinase is capable of catalyzing the 14N/15N positional isotope exchange of 3-15N-PCr in the presence of MgADP, but not in its absence. Further, the exchange does not take place when labeled PCr is resynthesized exclusively from the ternary complex E X Cr X MgATP as opposed to either E X Cr or free Cr. This suggests that the enzyme both imparts an additional rotational barrier to creatine in the complex and catalyzes the transfer of phosphoryl group with essentially complete regiospecificity

  1. Microstructure and corrosion resistance of CrAlSiN, CrAlSiN+DLC, and CrN coatings

    Directory of Open Access Journals (Sweden)

    K. Lukaszkowicz

    2011-03-01

    Full Text Available Purpose: The main aim of the research was the investigation of microstructure and corrosion resistance of the nanostructured CrAlSiN, CrAlSiN+DLC, CrN coatings deposited by cathodic arc evaporation method onto hot work tool steel substrate.Design/methodology/approach: Observations of surface and microstructure of the deposited coatings were carried out on cross sections in the SUPRA 35 scanning electron microscope. Diffraction and thin film microstructure were tested with the use of the JEOL JEM 3010UHR transmission electron microscope. X-ray study for the analyzed coatings was carried out using X´Pert PRO system. A phase identification of the investigated coatings was carried out in Bragg-Brentano geometry (XRD, and in grazing incidence geometry (GIXRD. Investigation of the electrochemical corrosion behaviour of the samples done in a PGP 201 Potentiostat/Galvanostat, using a conventional three-electrode cell. To simulate the aggressive media, 1-M HCl solution was used under aerated conditions and room temperature.Findings: It was found that the microstructure of the PVD coatings consisted of fine nanocrystallites, of an average size of 8 nm -13 nm, depending on the coating type. The morphology of the coatings fracture is characteristic of a dense microstructure. Basing on the GIXRD pattern of the investigated coatings, only fcc phases was encountered. The tests carried out with the use of a GDOS technique indicate the occurrence of a transition zone between the substrate material and the coating. Deposition of the PVD coatings increases the hardness of the tool steel surface up to 22-40 GPa. The CrN coated sample showed the best corrosion resistance.Practical implications: In order to evaluate with more detail the possibility of applying these nanocomposite coatings for protection of tool steels, further investigations should be undertaken in order to determine the thermal fatigue resistance of the coatings. The very good mechanical

  2. Functional Analysis of Arabidopsis Sucrose Transporters

    Energy Technology Data Exchange (ETDEWEB)

    John M. Ward

    2009-03-31

    Sucrose is the main photosynthetic product that is transported in the vasculature of plants. The long-distance transport of carbohydrates is required to support the growth and development of net-importing (sink) tissues such as fruit, seeds and roots. This project is focused on understanding the transport mechanism sucrose transporters (SUTs). These are proton-coupled sucrose uptake transporters (membrane proteins) that are required for transport of sucrose in the vasculature and uptake into sink tissues. The accomplishments of this project included: 1) the first analysis of substrate specificity for any SUT. This was accomplished using electrophysiology to analyze AtSUC2, a sucrose transporter from companion cells in Arabidopsis. 2) the first analysis of the transport activity for a monocot SUT. The transport kinetics and substrate specificity of HvSUT1 from barley were studied. 3) the first analysis of a sucrose transporter from sugarcane. and 4) the first analysis of transport activity of a sugar alcohol transporter homolog from plants, AtPLT5. During this period four primary research papers, funded directly by the project, were published in refereed journals. The characterization of several sucrose transporters was essential for the current effort in the analysis of structure/function for this gene family. In particular, the demonstration of strong differences in substrate specificity between type I and II SUTs was important to identify targets for site-directed mutagenesis.

  3. Influence of Ar/Kr ratio and pulse parameters in a Cr-N high power pulse magnetron sputtering process on plasma and coating properties

    International Nuclear Information System (INIS)

    Krypton is sometimes used in physical vapor deposition processes due to its greater atomic mass and size compared to argon, which leads to a lower gas incorporation and may have beneficial effects on kinetics of the coating growth. In this paper, the authors investigate the plasma composition and properties of deposited high power pulse magnetron sputtering Cr-N coatings for discharges with various Ar/Kr ratios and for various pulse lengths of 40 μs, 80 μs, and 200 μs, keeping the average discharge power constant. The results show that an addition of Kr influences the discharge process by altering the ignition and peak values of the discharge current. This influences the metal ion generation and growth conditions on the substrate by reducing the nucleation site densities, leading to a predominantly columnar grow. However, the deposition rate is highest for an Ar/Kr ratio of 120/80. The integral of the metal ion and atom emission exhibits the same trend, having a maximum for Ar/Kr ratio of 120/80. By decreasing the pulse length, the deposition rate of coatings decreases, while the hardness increases

  4. On the mechanisms of the formation of nanocrystalline Cr-N and V-N coatings upon ion-beam-assisted deposition

    Science.gov (United States)

    Guglya, A. G.

    2010-01-01

    The paper generalizes the results of investigations performed at the Kharkov Institute of Physics and Technology, National Scientific Center, aimed at the development and analysis of nanocrystalline Cr-N and V-N coatings produced by the method of ion-beam-assisted deposition (IBAD method). The effect of temperature of the process and the ratio between its ionic and atomic components (N+/Cr, V) on the resistivity of the coatings has been studied. It has been found that the ion-assisted irradiation leads to the formation of nanocrystalline nitride structures, whose phase composition depends not only on the concentration of nitrogen implanted by the ion beam, but also on the amount of the physical adsorption of nitrogen, including its adsorption from the residual atmosphere. It has been shown that the IBAD method can be used for both production of dense nanocrystalline composites and creation of nanoporous structures. It has been found that the grain size, the internal porosity, and the electrophysical characteristics of the coatings are intimately connected with the Gibbs energy of the nitride phases. The mechanisms responsible for the formation of such coatings have been discussed in terms of the thermodynamics of the nitride-formation process.

  5. POPCORN Functions in the Auxin Pathway to Regulate Embryonic Body Plan and Meristem Organization in Arabidopsis

    NARCIS (Netherlands)

    Xiang, D.Q.; Yang, H.; Venglat, P.; Cao, Y.G.; Wen, R.; Ren, M.Z.; Stone, S.; Wang, E.; Wang, H.; Xiao, W.; Weijers, D.; Berleth, T.; Laux, T.; Selvaraj, G.; Datla, R.

    2011-01-01

    The shoot and root apical meristems (SAM and RAM) formed during embryogenesis are crucial for postembryonic plant development. We report the identification of POPCORN (PCN), a gene required for embryo development and meristem organization in Arabidopsis thaliana. Map-based cloning revealed that PCN

  6. Membrane association of the Arabidopsis ARF exchange factor GNOM involves interaction of conserved domains

    DEFF Research Database (Denmark)

    Anders, Nadine; Nielsen, Michael M.; Keicher, Jutta;

    2008-01-01

    The GNOM protein plays a fundamental role in Arabidopsis thaliana development by regulating endosome-to-plasma membrane trafficking required for polar localization of the auxin efflux carrier PIN1. GNOM is a family member of large ARF guanine nucleotide exchange factors (ARF-GEFs), which regulate...

  7. 3D fluorescent in situ hybridization using Arabidopsis leaf cryosections and isolated nuclei

    Directory of Open Access Journals (Sweden)

    Biot Eric

    2009-08-01

    Full Text Available Abstract Background Fluorescent hybridization techniques are widely used to study the functional organization of different compartments within the mammalian nucleus. However, few examples of such studies are known in the plant kingdom. Indeed, preservation of nuclei 3D structure, which is required for nuclear organization studies, is difficult to fulfill. Results We report a rapid protocol for fluorescent in situ hybridization (FISH performed on 3D isolated nuclei and thin cryosectioned leaves of Arabidopsis thaliana. The use of direct labeling minimized treatment steps, shortening the overall procedure. Using image analysis, we measured different parameters related to nucleus morphology and overall 3D structure. Conclusion Our work describes a 3D-FISH protocol that preserves the 3D structure of Arabidopsis interphase nuclei. Moreover, we report for the first time FISH using cryosections of Arabidopsis leaves. This protocol is a valuable tool to investigate nuclear architecture and chromatin organization.

  8. Arabidopsis CDS blastp result: AK119708 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK119708 002-157-E08 At1g28330.1 dormancy-associated protein, putative (DRM1) identical to dormancy...-associated protein [Arabidopsis thaliana] GI:2995990; similar to dormancy-associated protei

  9. Arabidopsis CDS blastp result: AK060981 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK060981 006-202-H08 At1g28330.1 dormancy-associated protein, putative (DRM1) identical to dormancy...-associated protein [Arabidopsis thaliana] GI:2995990; similar to dormancy-associated protei

  10. Arabidopsis CDS blastp result: AK111736 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111736 J023047L09 At1g68370.1 gravity -responsive protein / altered response to gravity ... protein ... (ARG1) identical to Altered Response to Gravity ... [Arabidopsis thaliana] GI:4249662; contains Pfam p ...

  11. Arabidopsis CDS blastp result: AK070093 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK070093 J023041M10 At2g39290.1 phosphatidylglycerolphosphate synthase (PGS1) identical to phosphati...dylglycerolphosphate synthase GI:13365519 from [Arabidopsis thaliana] 7e-78 ...

  12. Arabidopsis CDS blastp result: AK060009 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK060009 006-302-D03 At2g39290.1 phosphatidylglycerolphosphate synthase (PGS1) identical to phosphati...dylglycerolphosphate synthase GI:13365519 from [Arabidopsis thaliana] 8e-71 ...

  13. Arabidopsis CDS blastp result: AK058419 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK058419 001-015-D06 At4g16280.3 flowering time ... control protein / FCA gamma (FCA) identical to S ... P|O04425 Flowering time ... control protein FCA {Arabidopsis thaliana}; four a ...

  14. Arabidopsis CDS blastp result: AK073225 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK073225 J033023C04 At4g16280.3 flowering time ... control protein / FCA gamma (FCA) identical to SP ... |O04425 Flowering time ... control protein FCA {Arabidopsis thaliana}; four a ...

  15. Arabidopsis CDS blastp result: AK102695 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK102695 J033103F21 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  16. Arabidopsis CDS blastp result: AK102134 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK102134 J033085F12 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  17. Arabidopsis CDS blastp result: AK066835 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK066835 J013087I16 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 1e-171 ...

  18. Arabidopsis CDS blastp result: AK065259 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK065259 J013002J18 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  19. Arabidopsis CDS blastp result: AK100523 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK100523 J023100P04 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  20. Arabidopsis CDS blastp result: AK288065 [KOME

    Lifescience Database Archive (English)

    Full Text Available al to sulfate tansporter Sultr1;3 [Arabidopsis thaliana] GI:10716805; contains Pfam profile PF00916: Sulfate... transporter family; contains Pfam profile PF01740: STAS domain; contains TIGRfam profile TIGR00815: sulfate permease 1e-145 ...

  1. Arabidopsis CDS blastp result: AK288002 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288002 J075110B01 At1g68510.1 68414.m07826 LOB domain protein 42 ... / lateral organ boundaries do ... main protein 42 ... (LBD42 ) identical to LOB DOMAIN 42 ... [Arabidopsis th ...

  2. Arabidopsis CDS blastp result: AK241043 [KOME

    Lifescience Database Archive (English)

    Full Text Available upted by a stop codon, creating non-consensus donor and acceptor splice sites. 2e-41 ... ...tical to SP|P92997 Germin-like protein subfamily 1 member 13 precursor {Arabidopsis thaliana}; exon 2 interr

  3. Arabidopsis CDS blastp result: AK243135 [KOME

    Lifescience Database Archive (English)

    Full Text Available upted by a stop codon, creating non-consensus donor and acceptor splice sites. 7e-43 ... ...tical to SP|P92997 Germin-like protein subfamily 1 member 13 precursor {Arabidopsis thaliana}; exon 2 interr

  4. Arabidopsis CDS blastp result: AK111785 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111785 J023089N11 At5g62310.1 incomplete root hair ... elongation (IRE) / protein kinase, putative ... nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  5. Arabidopsis CDS blastp result: AK243050 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243050 J100011E04 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  6. Arabidopsis CDS blastp result: AK242758 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242758 J090051H03 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  7. Arabidopsis CDS blastp result: AK242717 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242717 J090043H19 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  8. Arabidopsis CDS blastp result: AK288095 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288095 J075191E21 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  9. Arabidopsis CDS blastp result: AK242638 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242638 J090023J02 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  10. Arabidopsis CDS blastp result: AK242651 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242651 J090026B08 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  11. Arabidopsis CDS blastp result: AK287631 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287631 J065073J24 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  12. Arabidopsis CDS blastp result: AK288923 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288923 J090081P06 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  13. Arabidopsis CDS blastp result: AK242271 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242271 J075187A19 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  14. Arabidopsis CDS blastp result: AK242681 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242681 J090032N04 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  15. Arabidopsis CDS blastp result: AK243656 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243656 J100088L22 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  16. Arabidopsis CDS blastp result: AK241519 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241519 J065170E12 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  17. Arabidopsis CDS blastp result: AK240655 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240655 J023135E11 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  18. Arabidopsis CDS blastp result: AK242733 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242733 J090047O22 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  19. Arabidopsis CDS blastp result: AK242859 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242859 J090073L24 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  20. Arabidopsis CDS blastp result: AK243187 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243187 J100039E11 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  1. Arabidopsis CDS blastp result: AK242550 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242550 J080319D10 At2g35630.1 68415.m04369 microtubule organization 1 protein (MO...R1) identical to microtubule organization 1 protein GI:14317953 from [Arabidopsis thaliana] 5e-44 ...

  2. Arabidopsis CDS blastp result: AK101368 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK101368 J033035L13 At5g24270.1 calcineurin B-like protein, putative / calcium sensor ... homolog (S ... OS3) identical to calcium sensor ... homolog [Arabidopsis thaliana] GI:3309575; similar ...

  3. Arabidopsis CDS blastp result: AK111570 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111570 J013071C24 At5g24270.1 calcineurin B-like protein, putative / calcium sensor ... homolog (S ... OS3) identical to calcium sensor ... homolog [Arabidopsis thaliana] GI:3309575; similar ...

  4. Arabidopsis CDS blastp result: AK243065 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243065 J100015N03 At5g24270.1 68418.m02855 calcineurin B-like protein, putative / calcium sensor ... or homolog (SOS3) identical to calcium sensor ... homolog [Arabidopsis thaliana] GI:3309575; similar ...

  5. The fifth international conference on Arabidopsis research

    Energy Technology Data Exchange (ETDEWEB)

    Hangarter, R.; Scholl, R.; Davis, K.; Feldmann, K.

    1993-12-31

    This volume contains abstracts of oral and poster presentations made in conjunction with the Fifth International Conference on Arabidopsis Research held August 19--22, 1993 at the Ohio State University, Columbus, Ohio.

  6. Arabidopsis CDS blastp result: AK070528 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK070528 J023060D13 At3g10920.1 superoxide dismutase [Mn], mitochondrial (SODA) / manganese ... supe ... roxide dismutase (MSD1) identical to manganese ... superoxide dismutase [Arabidopsis thaliana] gi|327 ...

  7. Arabidopsis CDS blastp result: AK119904 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK119904 002-182-A05 At3g10920.1 superoxide dismutase [Mn], mitochondrial (SODA) / manganese ... sup ... eroxide dismutase (MSD1) identical to manganese ... superoxide dismutase [Arabidopsis thaliana] gi|327 ...

  8. Arabidopsis CDS blastp result: AK104030 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK104030 001-020-C01 At3g10920.1 superoxide dismutase [Mn], mitochondrial (SODA) / manganese ... sup ... eroxide dismutase (MSD1) identical to manganese ... superoxide dismutase [Arabidopsis thaliana] gi|327 ...

  9. Arabidopsis CDS blastp result: AK104160 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK104160 006-211-E09 At3g10920.1 superoxide dismutase [Mn], mitochondrial (SODA) / manganese ... sup ... eroxide dismutase (MSD1) identical to manganese ... superoxide dismutase [Arabidopsis thaliana] gi|327 ...

  10. Arabidopsis CDS blastp result: AK287459 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287459 J043019O07 At4g37000.1 68417.m05242 accelerated cell death ... 2 (ACD2) identical to accele ... rated cell death ... 2 (ACD2) GI:12484129 from [Arabidopsis thaliana] 4 ...

  11. Arabidopsis CDS blastp result: AK288034 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288034 J075140H07 At4g37000.1 68417.m05242 accelerated cell death ... 2 (ACD2) identical to accele ... rated cell death ... 2 (ACD2) GI:12484129 from [Arabidopsis thaliana] 5 ...

  12. Arabidopsis CDS blastp result: AK111576 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111576 J013075J23 At1g01510.1 C-terminal binding protein (ANGUSTIFOLIA) nearly id...entical to C-terminal binding protein ANGUSTIFOLIA [Arabidopsis thaliana] GI:15408535; contains Pfam profile

  13. Arabidopsis CDS blastp result: AK120838 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK120838 J023022B11 At1g01510.1 C-terminal binding protein (ANGUSTIFOLIA) nearly id...entical to C-terminal binding protein ANGUSTIFOLIA [Arabidopsis thaliana] GI:15408535; contains Pfam profile

  14. Arabidopsis CDS blastp result: AK111921 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111921 001-013-A10 At1g01510.1 C-terminal binding protein (ANGUSTIFOLIA) nearly i...dentical to C-terminal binding protein ANGUSTIFOLIA [Arabidopsis thaliana] GI:15408535; contains Pfam profil

  15. Arabidopsis CDS blastp result: AK073140 [KOME

    Lifescience Database Archive (English)

    Full Text Available me 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains a Ser/Thr protein...AK073140 J033022I01 At2g39840.1 serine/threonine protein phosphatase PP1 isozyme 4 (TOPP4) / phosphoprotein... phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphatase PP1 isozy... phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 1e-168 ...

  16. Arabidopsis CDS blastp result: AK120439 [KOME

    Lifescience Database Archive (English)

    Full Text Available me 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains a Ser/Thr protein...AK120439 J013098H20 At2g39840.1 serine/threonine protein phosphatase PP1 isozyme 4 (TOPP4) / phosphoprotein... phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphatase PP1 isozy... phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 1e-154 ...

  17. Arabidopsis CDS blastp result: AK121378 [KOME

    Lifescience Database Archive (English)

    Full Text Available me 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains a Ser/Thr protein...AK121378 J023127F14 At2g39840.1 serine/threonine protein phosphatase PP1 isozyme 4 (TOPP4) / phosphoprotein... phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphatase PP1 isozy... phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 1e-142 ...

  18. Arabidopsis CDS blastp result: AK063856 [KOME

    Lifescience Database Archive (English)

    Full Text Available yme 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains a Ser/Thr protein...AK063856 001-122-D05 At2g39840.1 serine/threonine protein phosphatase PP1 isozyme 4 (TOPP4) / phosphoprotein... phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphatase PP1 isoz... phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 6e-46 ...

  19. Terpene Specialized Metabolism in Arabidopsis thaliana

    OpenAIRE

    Tholl, Dorothea; Lee, Sungbeom

    2011-01-01

    Terpenes constitute the largest class of plant secondary (or specialized) metabolites, which are compounds of ecological function in plant defense or the attraction of beneficial organisms. Using biochemical and genetic approaches, nearly all Arabidopsis thaliana (Arabidopsis) enzymes of the core biosynthetic pathways producing the 5-carbon building blocks of terpenes have been characterized and closer insight has been gained into the transcriptional and posttranscriptional/translational mech...

  20. The pattern of polymorphism in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    2005-07-01

    Full Text Available We resequenced 876 short fragments in a sample of 96 individuals of Arabidopsis thaliana that included stock center accessions as well as a hierarchical sample from natural populations. Although A. thaliana is a selfing weed, the pattern of polymorphism in general agrees with what is expected for a widely distributed, sexually reproducing species. Linkage disequilibrium decays rapidly, within 50 kb. Variation is shared worldwide, although population structure and isolation by distance are evident. The data fail to fit standard neutral models in several ways. There is a genome-wide excess of rare alleles, at least partially due to selection. There is too much variation between genomic regions in the level of polymorphism. The local level of polymorphism is negatively correlated with gene density and positively correlated with segmental duplications. Because the data do not fit theoretical null distributions, attempts to infer natural selection from polymorphism data will require genome-wide surveys of polymorphism in order to identify anomalous regions. Despite this, our data support the utility of A. thaliana as a model for evolutionary functional genomics.

  1. Arabidopsis seedling flood-inoculation technique: a rapid and reliable assay for studying plant-bacterial interactions

    Directory of Open Access Journals (Sweden)

    Uppalapati Srinivasa R

    2011-10-01

    Full Text Available Abstract Background The Arabidopsis thaliana-Pseudomonas syringae model pathosystem is one of the most widely used systems to understand the mechanisms of microbial pathogenesis and plant innate immunity. Several inoculation methods have been used to study plant-pathogen interactions in this model system. However, none of the methods reported to date are similar to those occurring in nature and amicable to large-scale mutant screens. Results In this study, we developed a rapid and reliable seedling flood-inoculation method based on young Arabidopsis seedlings grown on MS medium. This method has several advantages over conventional soil-grown plant inoculation assays, including a shorter growth and incubation period, ease of inoculation and handling, uniform infection and disease development, requires less growth chamber space and is suitable for high-throughput screens. In this study we demonstrated the efficacy of the Arabidopsis seedling assay to study 1 the virulence factors of P. syringae pv. tomato DC3000, including type III protein secretion system (TTSS and phytotoxin coronatine (COR; 2 the effector-triggered immunity; and 3 Arabidopsis mutants affected in salicylic acid (SA- and pathogen-associated molecular pattern (PAMPs-mediated pathways. Furthermore, we applied this technique to study nonhost resistance (NHR responses in Arabidopsis using nonhost pathogens, such as P. syringae pv. tabaci, pv. glycinea and pv. tomato T1, and confirmed the functional role of FLAGELLIN-SENSING 2 (FLS2 in NHR. Conclusions The Arabidopsis seedling flood-inoculation assay provides a rapid, efficient and economical method for studying Arabidopsis-Pseudomonas interactions with minimal growth chamber space and time. This assay could also provide an excellent system for investigating the virulence mechanisms of P. syringae. Using this method, we demonstrated that FLS2 plays a critical role in conferring NHR against nonhost pathovars of P. syringae, but not to

  2. SOT1, a pentatricopeptide repeat protein with a small MutS-related domain, is required for correct processing of plastid 23S-4.5S rRNA precursors in Arabidopsis thaliana.

    Science.gov (United States)

    Wu, Wenjuan; Liu, Sheng; Ruwe, Hannes; Zhang, Delin; Melonek, Joanna; Zhu, Yajuan; Hu, Xupeng; Gusewski, Sandra; Yin, Ping; Small, Ian D; Howell, Katharine A; Huang, Jirong

    2016-03-01

    Ribosomal RNA processing is essential for plastid ribosome biogenesis, but is still poorly understood in higher plants. Here, we show that SUPPRESSOR OF THYLAKOID FORMATION1 (SOT1), a plastid-localized pentatricopeptide repeat (PPR) protein with a small MutS-related domain, is required for maturation of the 23S-4.5S rRNA dicistron. Loss of SOT1 function leads to slower chloroplast development, suppression of leaf variegation, and abnormal 23S and 4.5S processing. Predictions based on the PPR motif sequences identified the 5' end of the 23S-4.5S rRNA dicistronic precursor as a putative SOT1 binding site. This was confirmed by electrophoretic mobility shift assay, and by loss of the abundant small RNA 'footprint' associated with this site in sot1 mutants. We found that more than half of the 23S-4.5S rRNA dicistrons in sot1 mutants contain eroded and/or unprocessed 5' and 3' ends, and that the endonucleolytic cleavage product normally released from the 5' end of the precursor is absent in a sot1 null mutant. We postulate that SOT1 binding protects the 5' extremity of the 23S-4.5S rRNA dicistron from exonucleolytic attack, and favours formation of the RNA structure that allows endonucleolytic processing of its 5' and 3' ends. PMID:26800847

  3. Advances in Arabidopsis research in China from 2006 to 2007

    Institute of Scientific and Technical Information of China (English)

    LIANG Yan; ZUO JianRu; YANG WeiCai

    2007-01-01

    @@ Arabidopsis thaliana, a model plant species, has a number of advantages over other plant species as an experimental organism due to many of its genetic and genomic features. The Chinese Arabidopsis community has made significant contributions to plant biology research in recent years[1,2]. In 2006, studies of plant biology in China received more attention than ever before, especially those pertaining to Arabidopsis research. Here we briefly summarize recent advances in Arabidopsis research in China.

  4. Residual stresses and thermal fatigue in CrN hard coatings characterized by high-temperature synchrotron X-ray diffraction

    International Nuclear Information System (INIS)

    The aim of this work is to analyze thermal fatigue in hard coatings/substrate composites (i) during slow heating and cooling and (ii) after local cyclic thermal laser pulse experiments. As a model system, CrN coatings with a thickness of 3 μm deposited on steel, hard metal and Si(100) substrates using reactive magnetron sputtering at a temperature of 350 oC are used. The coatings are at first characterized by means of in-situ high-temperature X-ray diffraction (XRD) using a commercially available temperature attachment and by applying heating and cooling rates of less than 0.3 oC/s. The treatment results in the expected reduction of intrinsic stresses which are independent of substrate material but strongly influenced by substrate roughness. To simulate local thermal fatigue, selected coating/substrate composites are thermally cycled using a laser beam of 6 mm in diameter in a temperature range of 50-850 oC applying up to 104 cycles and using heating and cooling rates of about 103oC/s. Subsequently, laser cycled samples are analyzed using synchrotron XRD, scanning electron microscopy and focused ion beam technique. Laser pulses cause a reduction of compressive stresses in the coatings and a development of tensile stresses in the substrates accompanied by formation of cracks and ripples. The results show that the changes of the local macro- and micro-strains/stresses in the coatings and in the underlying substrates are strongly interlinked. The stress relaxation in the coatings is caused by recovery effects, by micro-cracks formed in the tensely-stressed coating and by plastic deformation of the metallic substrates.

  5. Mining the active proteome of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Renier A. L. Van Der Hoorn

    2011-11-01

    Full Text Available Assigning functions to the >30.000 proteins encoded by the Arabidopsis genome is a challenging task of the Arabidopsis Functional Genomics Network. Although genome-wide technologies like proteomics and transcriptomics have generated a wealth of information that significantly accelerated gene annotation, protein activities are poorly predicted by transcript or protein levels as protein activities are post-translationally regulated. To directly display protein activities in Arabidopsis proteomes, we developed and applied Activity-based Protein Profiling (ABPP. ABPP is based on the use of small molecule probes that react with the catalytic residues of distinct protein classes in an activity-dependent manner. Labeled proteins are separated and detected from proteins gels and purified and identified by mass spectrometry. Using probes of six different chemotypes we have displayed of activities of 76 Arabidopsis proteins. These proteins represent over ten different protein classes that contain over 250 Arabidopsis proteins, including cysteine- serine- and metallo-proteases, lipases, acyltransferases, and the proteasome. We have developed methods for identification of in vivo labeled proteins using click-chemistry and for in vivo imaging with fluorescent probes. In vivo labeling has revealed novel protein activities and unexpected subcellular activities of the proteasome. Labeling of extracts displayed several differential activities e.g. of the proteasome during immune response and methylesterases during infection. These studies illustrate the power of ABPP to display the functional proteome and testify to a successful interdisciplinary collaboration involving chemical biology, organic chemistry and proteomics.

  6. Bioavailability of nanoparticulate hematite to Arabidopsis thaliana

    International Nuclear Information System (INIS)

    The environmental effects and bioavailability of nanoparticulate iron (Fe) to plants are currently unknown. Here, plant bioavailability of synthesized hematite Fe nanoparticles was evaluated using Arabidopsis thaliana (A. thaliana) as a model. Over 56-days of growing wild-type A. thaliana, the nanoparticle-Fe and no-Fe treatments had lower plant biomass, lower chlorophyll concentrations, and lower internal Fe concentrations than the Fe-treatment. Results for the no-Fe and nanoparticle-Fe treatments were consistently similar throughout the experiment. These results suggest that nanoparticles (mean diameter 40.9 nm, range 22.3–67.0 nm) were not taken up and therefore not bioavailable to A. thaliana. Over 14-days growing wild-type and transgenic (Type I/II proton pump overexpression) A. thaliana, the Type I plant grew more than the wild-type in the nanoparticle-Fe treatment, suggesting Type I plants cope better with Fe limitation; however, the nanoparticle-Fe and no-Fe treatments had similar growth for all plant types. -- Highlights: ► Iron nanoparticles were synthesized and assessed for bioavailability to Arabidopsis. ► Arabidopsis grew better in the presence of EDTA-bound iron than nanoparticulate iron. ► Arabidopsis grew the same in the presence of nanoparticulate iron compared to no iron. -- Synthesized iron nanoparticles were not bioavailable to Arabidopsis thaliana in agar nutrient media

  7. Recent Progress in Arabidopsis Research in China: A Preface

    Institute of Scientific and Technical Information of China (English)

    Zhi-Hong Xu

    2006-01-01

    @@ In 2002, a workshop on Arabidopsis research in China was held in Shanghai, when a small group of Chinese plant scientists was working on this model species. Since then, we have witnessed the rapid growth of Arabidopsis research in China. This special issue of Journal of Integrative Plant Biology is dedicated exclusively to the Fourth Workshop on Arabidopsis Research in China, scheduled on November 30, 2005, in Beijing. In addition to reports collected in this special issue, the Chinese Arabidopsis community has been able to make significant contributions to many research fields. Here, I briefly summarize recent advances in Arabidopsis research in China.

  8. The arabidopsis cyclic nucleotide interactome

    KAUST Repository

    Donaldson, Lara

    2016-05-11

    Background Cyclic nucleotides have been shown to play important signaling roles in many physiological processes in plants including photosynthesis and defence. Despite this, little is known about cyclic nucleotide-dependent signaling mechanisms in plants since the downstream target proteins remain unknown. This is largely due to the fact that bioinformatics searches fail to identify plant homologs of protein kinases and phosphodiesterases that are the main targets of cyclic nucleotides in animals. Methods An affinity purification technique was used to identify cyclic nucleotide binding proteins in Arabidopsis thaliana. The identified proteins were subjected to a computational analysis that included a sequence, transcriptional co-expression and functional annotation analysis in order to assess their potential role in plant cyclic nucleotide signaling. Results A total of twelve cyclic nucleotide binding proteins were identified experimentally including key enzymes in the Calvin cycle and photorespiration pathway. Importantly, eight of the twelve proteins were shown to contain putative cyclic nucleotide binding domains. Moreover, the identified proteins are post-translationally modified by nitric oxide, transcriptionally co-expressed and annotated to function in hydrogen peroxide signaling and the defence response. The activity of one of these proteins, GLYGOLATE OXIDASE 1, a photorespiratory enzyme that produces hydrogen peroxide in response to Pseudomonas, was shown to be repressed by a combination of cGMP and nitric oxide treatment. Conclusions We propose that the identified proteins function together as points of cross-talk between cyclic nucleotide, nitric oxide and reactive oxygen species signaling during the defence response.

  9. Arabidopsis CDS blastp result: AK243152 [KOME

    Lifescience Database Archive (English)

    Full Text Available ase PP1 isozyme 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains...P1 isozyme 4 (TOPP4) / phosphoprotein phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphat... a Ser/Thr protein phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 1e-154 ... ...AK243152 J100032N02 At2g39840.1 68415.m04893 serine/threonine protein phosphatase P

  10. Arabidopsis CDS blastp result: AK288069 [KOME

    Lifescience Database Archive (English)

    Full Text Available ase PP1 isozyme 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains...P1 isozyme 4 (TOPP4) / phosphoprotein phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphat... a Ser/Thr protein phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 6e-70 ... ...AK288069 J075158N05 At2g39840.1 68415.m04893 serine/threonine protein phosphatase P

  11. Interactions between co-expressed Arabidopsis sucrose transporters in the split-ubiquitin system

    Directory of Open Access Journals (Sweden)

    Lalonde Sylvie

    2003-03-01

    Full Text Available Abstract Background The Arabidopsis genome contains nine sucrose transporter paralogs falling into three clades: SUT1-like, SUT2 and SUT4. The carriers differ in their kinetic properties. Many transport proteins are known to exist as oligomers. The yeast-based split ubiquitin system can be used to analyze the ability of membrane proteins to interact. Results Promoter-GUS fusions were used to analyze the cellular expression of the three transporter genes in transgenic Arabidopsis plants. All three fusion genes are co-expressed in companion cells. Protein-protein interactions between Arabidopsis sucrose transporters were tested using the split ubiquitin system. Three paralogous sucrose transporters are capable of interacting as either homo- or heteromers. The interactions are specific, since a potassium channel and a glucose transporter did not show interaction with sucrose transporters. Also the biosynthetic and metabolizing enzymes, sucrose phosphate phosphatase and sucrose synthase, which were found to be at least in part bound to the plasma membrane, did not specifically interact with sucrose transporters. Conclusions The split-ubiquitin system provides a powerful tool to detect potential interactions between plant membrane proteins by heterologous expression in yeast, and can be used to screen for interactions with membrane proteins as baits. Like other membrane proteins, the Arabidopsis sucrose transporters are able to form oligomers. The biochemical approaches are required to confirm the in planta interaction.

  12. Analysis of Arabidopsis mutants deficient in flavonoid biosynthesis

    International Nuclear Information System (INIS)

    Eleven loci that play a role in the synthesis of flavonoids in Arabidopsis are described. Mutations at these loci, collectively named transparent testa (tt), disrupt the synthesis of brown pigments in the seed coat (testa). Several of these loci (tt3, tt4, tt5 and ttg) are also required for the accumulation of purple anthocyanins in leaves and stems and one locus (ttg) plays additional roles in trichome and root hair development. Specific functions were previously assigned to tt1-7 and ttg. Here, the results of additional genetic, biochemical and molecular analyses of these mutants are described. Genetic map positions were determined for tt8, tt9 and tt10. Thin-layer chromatography identified tissue- and locus-specific differences in the flavonols and anthocyanidins synthesized by mutant and wild-type plants. It was found that UV light reveals distinct differences in the floral tissues of tt3, tt4, tt5, tt6 and ttg, even though these tissues are indistinguishable under visible light. Evidence was also uncovered that tt8 and ttg specifically affect dihydroflavonol reductase gene expression. A summary of these and previously published results are incorporated into an overview of the genetics of flavonoid biosynthesis in Arabidopsis

  13. Ethylene Inhibits Cell Proliferation of the Arabidopsis Root Meristem.

    Science.gov (United States)

    Street, Ian H; Aman, Sitwat; Zubo, Yan; Ramzan, Aleena; Wang, Xiaomin; Shakeel, Samina N; Kieber, Joseph J; Schaller, G Eric

    2015-09-01

    The root system of plants plays a critical role in plant growth and survival, with root growth being dependent on both cell proliferation and cell elongation. Multiple phytohormones interact to control root growth, including ethylene, which is primarily known for its role in controlling root cell elongation. We find that ethylene also negatively regulates cell proliferation at the root meristem of Arabidopsis (Arabidopsis thaliana). Genetic analysis indicates that the inhibition of cell proliferation involves two pathways operating downstream of the ethylene receptors. The major pathway is the canonical ethylene signal transduction pathway that incorporates CONSTITUTIVE TRIPLE RESPONSE1, ETHYLENE INSENSITIVE2, and the ETHYLENE INSENSITIVE3 family of transcription factors. The secondary pathway is a phosphorelay based on genetic analysis of receptor histidine kinase activity and mutants involving the type B response regulators. Analysis of ethylene-dependent gene expression and genetic analysis supports SHORT HYPOCOTYL2, a repressor of auxin signaling, as one mediator of the ethylene response and furthermore, indicates that SHORT HYPOCOTYL2 is a point of convergence for both ethylene and cytokinin in negatively regulating cell proliferation. Additional analysis indicates that ethylene signaling contributes but is not required for cytokinin to inhibit activity of the root meristem. These results identify key elements, along with points of cross talk with cytokinin and auxin, by which ethylene negatively regulates cell proliferation at the root apical meristem. PMID:26149574

  14. Arabidopsis CDS blastp result: AK066771 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK066771 J013083K07 At1g01170.1 ozone-responsive stress-related protein, putative s...imilar to stress-related ozone-induced protein AtOZI1 (GI:790583) [Arabidopsis thaliana]; contains 1 predicted transmembrane domain; 2e-29 ...

  15. Arabidopsis CDS blastp result: AK059353 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK059353 001-026-D01 At1g01170.1 ozone-responsive stress-related protein, putative ...similar to stress-related ozone-induced protein AtOZI1 (GI:790583) [Arabidopsis thaliana]; contains 1 predicted transmembrane domain; 2e-29 ...

  16. Arabidopsis CDS blastp result: AK059160 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK059160 001-023-D05 At1g01170.1 ozone-responsive stress-related protein, putative ...similar to stress-related ozone-induced protein AtOZI1 (GI:790583) [Arabidopsis thaliana]; contains 1 predicted transmembrane domain; 3e-28 ...

  17. Arabidopsis CDS blastp result: AK242849 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242849 J090072M15 At1g68370.1 68414.m07809 gravity -responsive protein / altered response to gravity ... ty protein (ARG1) identical to Altered Response to Gravity ... [Arabidopsis thaliana] GI:4249662; contains Pfam p ...

  18. Arabidopsis CDS blastp result: AK288959 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288959 J090084E19 At1g68370.1 68414.m07809 gravity -responsive protein / altered response to gravity ... ty protein (ARG1) identical to Altered Response to Gravity ... [Arabidopsis thaliana] GI:4249662; contains Pfam p ...

  19. Arabidopsis CDS blastp result: AK243008 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243008 J090097H12 At1g68370.1 68414.m07809 gravity -responsive protein / altered response to gravity ... ty protein (ARG1) identical to Altered Response to Gravity ... [Arabidopsis thaliana] GI:4249662; contains Pfam p ...

  20. Arabidopsis CDS blastp result: AK288072 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288072 J075161I05 At1g68370.1 68414.m07809 gravity -responsive protein / altered response to gravity ... ty protein (ARG1) identical to Altered Response to Gravity ... [Arabidopsis thaliana] GI:4249662; contains Pfam p ...

  1. Arabidopsis CDS blastp result: AK243178 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243178 J100036P15 At1g68370.1 68414.m07809 gravity -responsive protein / altered response to gravity ... ty protein (ARG1) identical to Altered Response to Gravity ... [Arabidopsis thaliana] GI:4249662; contains Pfam p ...

  2. Arabidopsis CDS blastp result: AK243505 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243505 J100074N19 At1g68370.1 68414.m07809 gravity -responsive protein / altered response to gravity ... ty protein (ARG1) identical to Altered Response to Gravity ... [Arabidopsis thaliana] GI:4249662; contains Pfam p ...

  3. Arabidopsis CDS blastp result: AK287577 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287577 J065037N08 At1g68370.1 68414.m07809 gravity -responsive protein / altered response to gravity ... ty protein (ARG1) identical to Altered Response to Gravity ... [Arabidopsis thaliana] GI:4249662; contains Pfam p ...

  4. Protease gene families in Populus and Arabidopsis

    Directory of Open Access Journals (Sweden)

    Jansson Stefan

    2006-12-01

    Full Text Available Abstract Background Proteases play key roles in plants, maintaining strict protein quality control and degrading specific sets of proteins in response to diverse environmental and developmental stimuli. Similarities and differences between the proteases expressed in different species may give valuable insights into their physiological roles and evolution. Results We have performed a comparative analysis of protease genes in the two sequenced dicot genomes, Arabidopsis thaliana and Populus trichocarpa by using genes coding for proteases in the MEROPS database 1 for Arabidopsis to identify homologous sequences in Populus. A multigene-based phylogenetic analysis was performed. Most protease families were found to be larger in Populus than in Arabidopsis, reflecting recent genome duplication. Detailed studies on e.g. the DegP, Clp, FtsH, Lon, rhomboid and papain-Like protease families showed the pattern of gene family expansion and gene loss was complex. We finally show that different Populus tissues express unique suites of protease genes and that the mRNA levels of different classes of proteases change along a developmental gradient. Conclusion Recent gene family expansion and contractions have made the Arabidopsis and Populus complements of proteases different and this, together with expression patterns, gives indications about the roles of the individual gene products or groups of proteases.

  5. Arabidopsis CDS blastp result: AK241402 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241402 J065159A02 At4g19070.1 68417.m02810 cadmium-responsive protein / cadmium i...nduced protein (AS8) identical to cadmium induced protein AS8 SP:P42735 from [Arabidopsis thaliana] 3e-11 ...

  6. Arabidopsis CDS blastp result: AK242143 [KOME

    Lifescience Database Archive (English)

    Full Text Available ar to GI:6573119 from [Lycopersicon esculentum] (Plant Physiol. 122 (1), 292 (2000)) 3e-12 ... ... identical to SP|Q9C888 Phospholipase D epsilon (EC 3.1.4.4) (AtPLDepsilon) (PLD epsilon) (PLDalpha3) {Arabidopsis thaliana}; simil

  7. Arabidopsis CDS blastp result: AK242143 [KOME

    Lifescience Database Archive (English)

    Full Text Available ar to GI:6573119 from [Lycopersicon esculentum] (Plant Physiol. 122 (1), 292 (2000)) 6e-22 ... ... identical to SP|Q9C888 Phospholipase D epsilon (EC 3.1.4.4) (AtPLDepsilon) (PLD epsilon) (PLDalpha3) {Arabidopsis thaliana}; simil

  8. Arabidopsis CDS blastp result: AK240654 [KOME

    Lifescience Database Archive (English)

    Full Text Available ar to GI:6573119 from [Lycopersicon esculentum] (Plant Physiol. 122 (1), 292 (2000)) 1e-160 ... ... identical to SP|Q9C888 Phospholipase D epsilon (EC 3.1.4.4) (AtPLDepsilon) (PLD epsilon) (PLDalpha3) {Arabidopsis thaliana}; simil

  9. Arabidopsis CDS blastp result: AK242290 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242290 J075191E07 At4g13870.1 68417.m02148 Werner Syndrome-like exonuclease (WEX)... contains Pfam profile PF01612: 3'-5' exonuclease; identical to Werner Syndrome-like exonuclease [Arabidopsis thaliana] GP:28195109 gb:AAO33765 1e-20 ...

  10. Arabidopsis CDS blastp result: AK063585 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK063585 001-118-A04 At4g13870.2 Werner Syndrome-like exonuclease (WEX) contains Pf...am profile PF01612: 3'-5' exonuclease; identical to Werner Syndrome-like exonuclease [Arabidopsis thaliana] GP:28195109 gb:AAO33765 6e-16 ...

  11. Arabidopsis CDS blastp result: AK242290 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242290 J075191E07 At4g13870.2 68417.m02149 Werner Syndrome-like exonuclease (WEX)... contains Pfam profile PF01612: 3'-5' exonuclease; identical to Werner Syndrome-like exonuclease [Arabidopsis thaliana] GP:28195109 gb:AAO33765 1e-20 ...

  12. Arabidopsis CDS blastp result: AK243230 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243230 J100044L04 At1g19850.1 68414.m02490 transcription factor MONOPTEROS (MP) /... auxin-responsive protein (IAA24) / auxin response factor 5 (ARF5) identical to transcription factor MONOPTEROS (MP/IAA24/ARF5) SP:P93024 from [Arabidopsis thaliana] 2e-65 ...

  13. Arabidopsis CDS blastp result: AK103452 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK103452 J033129I11 At1g19850.1 transcription factor MONOPTEROS (MP) / auxin-respon...sive protein (IAA24) / auxin response factor 5 (ARF5) identical to transcription factor MONOPTEROS (MP/IAA24/ARF5) SP:P93024 from [Arabidopsis thaliana] 1e-166 ...

  14. Arabidopsis CDS blastp result: AK318617 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK318617 J100090H20 At1g19850.1 68414.m02490 transcription factor MONOPTEROS (MP) /... auxin-responsive protein (IAA24) / auxin response factor 5 (ARF5) identical to transcription factor MONOPTEROS (MP/IAA24/ARF5) SP:P93024 from [Arabidopsis thaliana] 2e-63 ...

  15. Arabidopsis CDS blastp result: AK287832 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287832 J065187F20 At1g30950.1 68414.m03790 unusual floral organ (UFO ) / F-box family protein ( ... ubunit; almost identical to unusual floral organs (UFO )GI:4376159 from [Arabidopsis thaliana] Landsberg-e ...

  16. Arabidopsis CDS blastp result: AK241547 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241547 J065176G22 At1g30950.1 68414.m03790 unusual floral organ (UFO ) / F-box family protein ( ... ubunit; almost identical to unusual floral organs (UFO )GI:4376159 from [Arabidopsis thaliana] Landsberg-e ...

  17. Arabidopsis CDS blastp result: AK242616 [KOME

    Lifescience Database Archive (English)

    Full Text Available ve contains PF00481: Protein phosphatase 2C domain; identical to protein phosphatase 2C (GI:4587992) [Arabidopsis thaliana] 2e-34 ... ...AK242616 J090017C19 At2g40180.1 68415.m04941 protein phosphatase 2C, putative / PP2C, putati

  18. Arabidopsis CDS blastp result: AK242846 [KOME

    Lifescience Database Archive (English)

    Full Text Available ve contains PF00481: Protein phosphatase 2C domain; identical to protein phosphatase 2C (GI:4587992) [Arabidopsis thaliana] 9e-12 ... ...AK242846 J090071I10 At2g40180.1 68415.m04941 protein phosphatase 2C, putative / PP2C, putati

  19. Arabidopsis CDS blastp result: AK241162 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241162 J065116A05 At5g54800.1 68418.m06826 glucose-6-phosphate/phosphate translocator, putative identic...al to glucose 6 phosphate/phosphate translocator [Arabidopsis thaliana] gi|7229675|gb|AAF42936 2e-11 ...

  20. Arabidopsis CDS blastp result: AK242098 [KOME

    Lifescience Database Archive (English)

    Full Text Available ve contains PF00481: Protein phosphatase 2C domain; identical to protein phosphatase 2C (GI:4587992) [Arabidopsis thaliana] 3e-22 ... ...AK242098 J075143H11 At2g40180.1 68415.m04941 protein phosphatase 2C, putative / PP2C, putati

  1. Arabidopsis CDS blastp result: AK243041 [KOME

    Lifescience Database Archive (English)

    Full Text Available ve contains PF00481: Protein phosphatase 2C domain; identical to protein phosphatase 2C (GI:4587992) [Arabidopsis thaliana] 4e-31 ... ...AK243041 J100008G07 At2g40180.1 68415.m04941 protein phosphatase 2C, putative / PP2C, putati

  2. Arabidopsis CDS blastp result: AK243539 [KOME

    Lifescience Database Archive (English)

    Full Text Available ve contains PF00481: Protein phosphatase 2C domain; identical to protein phosphatase 2C (GI:4587992) [Arabidopsis thaliana] 6e-34 ... ...AK243539 J100078G04 At2g40180.1 68415.m04941 protein phosphatase 2C, putative / PP2C, putati

  3. Arabidopsis CDS blastp result: AK242576 [KOME

    Lifescience Database Archive (English)

    Full Text Available ve contains PF00481: Protein phosphatase 2C domain; identical to protein phosphatase 2C (GI:4587992) [Arabidopsis thaliana] 3e-22 ... ...AK242576 J090009A15 At2g40180.1 68415.m04941 protein phosphatase 2C, putative / PP2C, putati

  4. Arabidopsis CDS blastp result: AK289111 [KOME

    Lifescience Database Archive (English)

    Full Text Available ve contains PF00481: Protein phosphatase 2C domain; identical to protein phosphatase 2C (GI:4587992) [Arabidopsis thaliana] 5e-20 ... ...AK289111 J090096N14 At2g40180.1 68415.m04941 protein phosphatase 2C, putative / PP2C, putati

  5. Arabidopsis CDS blastp result: AK289248 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK289248 J100079D02 At5g54800.1 68418.m06826 glucose-6-phosphate/phosphate translocator, putative identic...al to glucose 6 phosphate/phosphate translocator [Arabidopsis thaliana] gi|7229675|gb|AAF42936 7e-19 ...

  6. Arabidopsis CDS blastp result: AK287695 [KOME

    Lifescience Database Archive (English)

    Full Text Available ve contains PF00481: Protein phosphatase 2C domain; identical to protein phosphatase 2C (GI:4587992) [Arabidopsis thaliana] 3e-81 ... ...AK287695 J065129B08 At2g40180.1 68415.m04941 protein phosphatase 2C, putative / PP2C, putati

  7. Arabidopsis CDS blastp result: AK243048 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243048 J100010D20 At1g07370.1 68414.m00786 proliferating cell nuclear ... antigen 1 (PCNA1) identi ... cal to SP|Q9M7Q7 Proliferating cellular nuclear ... antigen 1 (PCNA 1) {Arabidopsis thaliana}; nearly ... identical to SP|Q43124 Proliferating cell nuclear ... antigen (PCNA) {Brassica napus}; contains Pfam pro ...

  8. Arabidopsis CDS blastp result: AK071591 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK071591 J023105C08 At2g29570.1 proliferating cell nuclear ... antigen 2 (PCNA2) identical to SP|Q9Z ... W35 Proliferating cell nuclear ... antigen 2 (PCNA 2) {Arabidopsis thaliana}; nearly ... identical to SP|Q43124 Proliferating cell nuclear ... antigen (PCNA) {Brassica napus}; contains Pfam pro ...

  9. Arabidopsis CDS blastp result: AK243048 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243048 J100010D20 At2g29570.1 68415.m03591 proliferating cell nuclear ... antigen 2 (PCNA2) identi ... cal to SP|Q9ZW35 Proliferating cell nuclear ... antigen 2 (PCNA 2) {Arabidopsis thaliana}; nearly ... identical to SP|Q43124 Proliferating cell nuclear ... antigen (PCNA) {Brassica napus}; contains Pfam pro ...

  10. Arabidopsis CDS blastp result: AK241265 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241265 J065132C02 At3g19450.1 68416.m02466 cinnamyl-alcohol dehydrogenase (CAD ) identical to S ... 523 Cinnamyl-alcohol dehydrogenase (EC 1.1.1.195) (CAD ) [Arabidopsis thaliana] 1e-81 ...

  11. Arabidopsis CDS blastp result: AK105739 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK105739 001-202-A05 At3g19450.1 cinnamyl-alcohol dehydrogenase (CAD ) identical to SP|P48523 Cin ... namyl-alcohol dehydrogenase (EC 1.1.1.195) (CAD ) [Arabidopsis thaliana] 2e-46 ...

  12. Arabidopsis CDS blastp result: AK243022 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243022 J100001E20 At3g19450.1 68416.m02466 cinnamyl-alcohol dehydrogenase (CAD ) identical to S ... 523 Cinnamyl-alcohol dehydrogenase (EC 1.1.1.195) (CAD ) [Arabidopsis thaliana] 4e-64 ...

  13. Arabidopsis CDS blastp result: AK287708 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287708 J065132C02 At3g19450.1 68416.m02466 cinnamyl-alcohol dehydrogenase (CAD ) identical to S ... 523 Cinnamyl-alcohol dehydrogenase (EC 1.1.1.195) (CAD ) [Arabidopsis thaliana] 1e-81 ...

  14. Arabidopsis CDS blastp result: AK121261 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK121261 J023104H13 At1g55350.4 calpain-type cysteine protease family identical to calpain...-like protein GI:20268660 from [Arabidopsis thaliana]; contains Pfam profiles: PF00648 Calpain family... cysteine protease, PF01067 Calpain large subunit,domain III; identical to cDNA calpain-like protein GI:20268659 0.0 ...

  15. Arabidopsis CDS blastp result: AK100867 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK100867 J023124E13 At2g29640.1 josephin family protein contains Pfam domain PF02099: Jose...phin; similar to Josephin-like protein (Swiss-Prot:O82391) [Arabidopsis thaliana] 7e-59 ...

  16. Arabidopsis CDS blastp result: AK065851 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK065851 J013041L15 At1g79010.1 NADH-ubiquinone oxidoreductase 23 kDa subunit, mitochondrial (TY ... ursor (EC 1.6.5.3) (EC 1.6.99.3) (Complex I-23KD) (CI -23KD) (Complex I- 28.5KD) (CI -28.5KD) {Arabidopsis ...

  17. Arabidopsis CDS blastp result: AK119532 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK119532 001-203-F01 At1g79010.1 NADH-ubiquinone oxidoreductase 23 kDa subunit, mitochondrial (T ... ursor (EC 1.6.5.3) (EC 1.6.99.3) (Complex I-23KD) (CI -23KD) (Complex I- 28.5KD) (CI -28.5KD) {Arabidopsis ...

  18. Arabidopsis CDS blastp result: AK243512 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243512 J100075C18 At4g16280.3 68417.m02471 flowering time ... control protein / FCA gamma (FCA) id ... entical to SP|O04425 Flowering time ... control protein FCA {Arabidopsis thaliana}; four a ...

  19. Arabidopsis CDS blastp result: AK243512 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243512 J100075C18 At4g16280.2 68417.m02470 flowering time ... control protein / FCA gamma (FCA) id ... entical to SP|O04425 Flowering time ... control protein FCA {Arabidopsis thaliana}; four a ...

  20. Arabidopsis CDS blastp result: AK242890 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242890 J090079L19 At5g16910.1 68418.m01982 cellulose synthase family protein similar to gi:2827143 cellulo...se synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 1e-130 ...

  1. Arabidopsis CDS blastp result: AK242585 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242585 J090010M20 At5g16910.1 68418.m01982 cellulose synthase family protein similar to gi:2827143 cellulo...se synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 2e-65 ...

  2. Arabidopsis CDS blastp result: AK110534 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK110534 002-168-A07 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 1e-114 ...

  3. Arabidopsis CDS blastp result: AK242585 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242585 J090010M20 At1g32180.1 68414.m03958 cellulose synthase family protein similar to cellulose... synthase catalytic subunit gi:2827143 from [Arabidopsis thaliana], cellulose synthase-9 (gi:9622890) from Zea mays 1e-24 ...

  4. Arabidopsis CDS blastp result: AK242601 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242601 J090014G03 At5g16910.1 68418.m01982 cellulose synthase family protein similar to gi:2827143 cellulo...se synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  5. Arabidopsis CDS blastp result: AK242601 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242601 J090014G03 At2g32540.1 68415.m03975 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 2e-45 ...

  6. Arabidopsis CDS blastp result: AK242585 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242585 J090010M20 At1g32180.1 68414.m03958 cellulose synthase family protein similar to cellulose... synthase catalytic subunit gi:2827143 from [Arabidopsis thaliana], cellulose synthase-9 (gi:9622890) from Zea mays 3e-66 ...

  7. Arabidopsis CDS blastp result: AK069071 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK069071 J023010H01 At2g32540.1 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 1e-167 ...

  8. Arabidopsis CDS blastp result: AK242585 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242585 J090010M20 At4g23990.1 68417.m03448 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 1e-124 ...

  9. Arabidopsis CDS blastp result: AK060286 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK060286 001-006-C08 At2g32540.1 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 6e-78 ...

  10. Arabidopsis CDS blastp result: AK242601 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242601 J090014G03 At4g38190.1 68417.m05391 cellulose synthase family protein similar to cellulose... synthase catalytic subunit gi:2827143 from [Arabidopsis thaliana], cellulose synthase-5 (gi:9622882) from Zea mays 0.0 ...

  11. Arabidopsis CDS blastp result: AK242601 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242601 J090014G03 At2g32530.1 68415.m03974 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 2e-29 ...

  12. Arabidopsis CDS blastp result: AK242601 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242601 J090014G03 At4g23990.1 68417.m03448 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 5e-25 ...

  13. Arabidopsis CDS blastp result: AK242585 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242585 J090010M20 At5g16910.1 68418.m01982 cellulose synthase family protein similar to gi:2827143 cellulo...se synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 1e-28 ...

  14. Arabidopsis CDS blastp result: AK105393 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK105393 001-123-B04 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  15. Arabidopsis CDS blastp result: AK242601 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242601 J090014G03 At4g23990.1 68417.m03448 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 8e-25 ...

  16. Arabidopsis CDS blastp result: AK242890 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242890 J090079L19 At1g32180.1 68414.m03958 cellulose synthase family protein similar to cellulose... synthase catalytic subunit gi:2827143 from [Arabidopsis thaliana], cellulose synthase-9 (gi:9622890) from Zea mays 1e-126 ...

  17. Arabidopsis CDS blastp result: AK242585 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242585 J090010M20 At4g38190.1 68417.m05391 cellulose synthase family protein similar to cellulose... synthase catalytic subunit gi:2827143 from [Arabidopsis thaliana], cellulose synthase-5 (gi:9622882) from Zea mays 8e-63 ...

  18. Arabidopsis CDS blastp result: AK242890 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242890 J090079L19 At4g38190.1 68417.m05391 cellulose synthase family protein similar to cellulose... synthase catalytic subunit gi:2827143 from [Arabidopsis thaliana], cellulose synthase-5 (gi:9622882) from Zea mays 1e-125 ...

  19. Arabidopsis CDS blastp result: AK242601 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242601 J090014G03 At1g32180.1 68414.m03958 cellulose synthase family protein similar to cellulose... synthase catalytic subunit gi:2827143 from [Arabidopsis thaliana], cellulose synthase-9 (gi:9622890) from Zea mays 0.0 ...

  20. Arabidopsis CDS blastp result: AK242601 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242601 J090014G03 At4g23990.1 68417.m03448 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 2e-26 ...

  1. Arabidopsis CDS blastp result: AK242890 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242890 J090079L19 At2g32540.1 68415.m03975 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 4e-47 ...

  2. Arabidopsis CDS blastp result: AK242585 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242585 J090010M20 At2g32540.1 68415.m03975 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 4e-98 ...

  3. Arabidopsis CDS blastp result: AK242585 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242585 J090010M20 At2g32530.1 68415.m03974 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 8e-98 ...

  4. Arabidopsis CDS blastp result: AK109812 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK109812 002-147-H02 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 5e-90 ...

  5. Arabidopsis CDS blastp result: AK242601 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242601 J090014G03 At2g32540.1 68415.m03975 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 3e-31 ...

  6. Arabidopsis CDS blastp result: AK121003 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK121003 J023045B21 At2g32540.1 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 1e-167 ...

  7. Arabidopsis CDS blastp result: AK242601 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242601 J090014G03 At2g32530.1 68415.m03974 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 5e-48 ...

  8. Arabidopsis CDS blastp result: AK242890 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242890 J090079L19 At4g23990.1 68417.m03448 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 1e-45 ...

  9. Arabidopsis CDS blastp result: AK242585 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242585 J090010M20 At4g38190.1 68417.m05391 cellulose synthase family protein similar to cellulose... synthase catalytic subunit gi:2827143 from [Arabidopsis thaliana], cellulose synthase-5 (gi:9622882) from Zea mays 4e-27 ...

  10. Arabidopsis CDS blastp result: AK061162 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK061162 006-209-A01 At2g32540.1 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 3e-35 ...

  11. Arabidopsis CDS blastp result: AK242890 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242890 J090079L19 At2g32530.1 68415.m03974 cellulose synthase family protein similar to cellulose... synthase catalytic subunit from Arabidopsis thaliana [gi:5230423], cellulose synthase-5 from Zea mays [gi:9622882] 4e-50 ...

  12. Arabidopsis CDS blastp result: AK066153 [KOME

    Lifescience Database Archive (English)

    Full Text Available pC almost identical to ClpC GI:2921158 from [Arabidopsis thaliana]; contains Pfam profile PF02861: Clp amino... terminal domain; contains Pfam profile PF00004: ATPase, AAA family; contains Pfam profile PF02151: UvrB/uvrC motif 0.0 ...

  13. Arabidopsis CDS blastp result: AK287906 [KOME

    Lifescience Database Archive (English)

    Full Text Available subunit / ClpC almost identical to ClpC GI:2921158 from [Arabidopsis thaliana]; contains Pfam profile PF028...61: Clp amino terminal domain; contains Pfam profile PF00004: ATPase, AAA family; contains Pfam profile PF02151: UvrB/uvrC motif 0.0 ...

  14. Arabidopsis CDS blastp result: AK069552 [KOME

    Lifescience Database Archive (English)

    Full Text Available pC almost identical to ClpC GI:2921158 from [Arabidopsis thaliana]; contains Pfam profile PF02861: Clp amino... terminal domain; contains Pfam profile PF00004: ATPase, AAA family; contains Pfam profile PF02151: UvrB/uvrC motif 0.0 ...

  15. Arabidopsis CDS blastp result: AK100126 [KOME

    Lifescience Database Archive (English)

    Full Text Available pC almost identical to ClpC GI:2921158 from [Arabidopsis thaliana]; contains Pfam profile PF02861: Clp amino... terminal domain; contains Pfam profile PF00004: ATPase, AAA family; contains Pfam profile PF02151: UvrB/uvrC motif 0.0 ...

  16. Arabidopsis CDS blastp result: AK058510 [KOME

    Lifescience Database Archive (English)

    Full Text Available lpC almost identical to ClpC GI:2921158 from [Arabidopsis thaliana]; contains Pfam profile PF02861: Clp amin...o terminal domain; contains Pfam profile PF00004: ATPase, AAA family; contains Pfam profile PF02151: UvrB/uvrC motif 0.0 ...

  17. Shotgun Proteomic Analysis of Arabidopsis thaliana Leaves

    Science.gov (United States)

    Two shotgun tandem mass spectrometry proteomics approaches, Multidimensional Protein Identification Technology (MudPIT) and 1D-Gel-LC-MS/MS, were used to identify Arabidopsis thaliana leaf proteins. These methods utilize different protein/peptide separation strategies. Detergents not compatible wit...

  18. Arabidopsis CDS blastp result: AK318553 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK318553 J075145A22 At4g11230.1 68417.m01819 respiratory burst ... oxidase, putative / NADPH oxidase ... , putative similar to respiratory burst ... oxidase homolog F [gi:3242456], RbohAp108 [gi:2654 ... 868] from Arabidopsis thaliana, respiratory burst ... oxidase homolog [GI:16549087] from Solanum tuberos ...

  19. Arabidopsis CDS blastp result: AK110694 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK110694 002-170-A08 At5g59560.2 sensitivity to red light reduced protein (SRR1) id...entical to sensitivity to red light reduced protein [Arabidopsis thaliana] GI:25527089; supporting cDNA gi|25527088|gb|AY127047.1| 1e-18 ...

  20. Arabidopsis CDS blastp result: AK099399 [KOME

    Lifescience Database Archive (English)

    Full Text Available 079; contains weak similarity to the SAPB protein (TR:E236624) [Arabidopsis thaliana]; similar to seven transme...AK099399 J013000O17 At3g05010.1 transmembrane protein, putative similar to GB:AAB61...mbrane domain orphan receptor (GI:4321619) [Mus musculus] contains 7 transmembrane domains; 2e-89 ...

  1. Arabidopsis CDS blastp result: AK241202 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241202 J065122B10 At3g20600.1 68416.m02607 non-race specific disease resistance protein (NDR1) ... protein (NDR1) GB:AF021346 [Arabidopsis thaliana] (Science ... 278 (5345), 1963-1965 (1997)) 2e-11 ...

  2. Arabidopsis CDS blastp result: AK240830 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240830 J065014C16 At3g12280.1 68416.m01533 retinoblastoma-related protein (RBR1) nearly identical to retin...oblastoma-related protein [Arabidopsis thaliana] GI:8777927; contains Pfam profiles: PF01858 retinoblastoma...-associated protein A domain, PF01857 retinoblastoma-associated protein B domain 0.0 ...

  3. Arabidopsis CDS blastp result: AK121431 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK121431 J023138G19 At3g12280.1 retinoblastoma-related protein (RBR1) nearly identical to retinoblastoma...-related protein [Arabidopsis thaliana] GI:8777927; contains Pfam profiles: PF01858 retinoblastoma...-associated protein A domain, PF01857 retinoblastoma-associated protein B domain 0.0 ...

  4. Arabidopsis CDS blastp result: AK064987 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK064987 J013001D03 At3g12280.1 retinoblastoma-related protein (RBR1) nearly identical to retinoblastoma...-related protein [Arabidopsis thaliana] GI:8777927; contains Pfam profiles: PF01858 retinoblastoma...-associated protein A domain, PF01857 retinoblastoma-associated protein B domain 0.0 ...

  5. Arabidopsis CDS blastp result: AK241627 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241627 J065187G05 At3g12280.1 68416.m01533 retinoblastoma-related protein (RBR1) nearly identical to retin...oblastoma-related protein [Arabidopsis thaliana] GI:8777927; contains Pfam profiles: PF01858 retinoblastoma...-associated protein A domain, PF01857 retinoblastoma-associated protein B domain 0.0 ...

  6. Arabidopsis CDS blastp result: AK241568 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241568 J065179E12 At3g56700.1 68416.m06307 male ... sterility protein, putative similar to SP|Q088 ... 91 Male ... sterility protein 2 {Arabidopsis thaliana}; contai ... ns Pfam profile PF03015: Male ... sterility protein 2e-70 ...

  7. Arabidopsis CDS blastp result: AK242888 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242888 J090079L06 At3g56700.1 68416.m06307 male ... sterility protein, putative similar to SP|Q088 ... 91 Male ... sterility protein 2 {Arabidopsis thaliana}; contai ... ns Pfam profile PF03015: Male ... sterility protein 8e-81 ...

  8. Arabidopsis CDS blastp result: AK287630 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287630 J065073I15 At5g22260.1 68418.m02593 male ... sterility 1 protein, putative (MS1) identical ... to male ... sterility 1 protein [Arabidopsis thaliana] gi|1555 ... fam profile PF00628: PHD-finger; identical to cDNA male ... sterility 1 protein (ms1 gene) GI:15554514 3e-78 ...

  9. Arabidopsis CDS blastp result: AK058440 [KOME

    Lifescience Database Archive (English)

    Full Text Available 20S proteasome beta subunit PBB1 (PBB1) GB:AAC32066 [Arabidopsis thaliana] (Genetics 149 (2), 677-692 (1998)); contains Pfam profile: PF00227 proteasome A-type and B-type; 1e-92 ...

  10. Arabidopsis CDS blastp result: AK119246 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK119246 001-121-C04 At5g26570.1 glycoside hydrolase starch -binding domain-containing protein si ... milar to SEX1 (starch ... excess) [Arabidopsis thaliana] GI:12044358; contai ... ns Pfam profile PF00686: Starch ... binding domain 1e-116 ...

  11. Arabidopsis CDS blastp result: AK072331 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK072331 J023039L19 At5g26570.1 glycoside hydrolase starch -binding domain-containing protein sim ... ilar to SEX1 (starch ... excess) [Arabidopsis thaliana] GI:12044358; contai ... ns Pfam profile PF00686: Starch ... binding domain 0.0 ...

  12. Arabidopsis CDS blastp result: AK107208 [KOME

    Lifescience Database Archive (English)

    Full Text Available Ala hydrolase, putative virtually identical to gr1-protein from [Arabidopsis thaliana] GI:3559811; similar t...AK107208 002-125-B11 At1g44350.1 IAA-amino acid hydrolase 6, putative (ILL6) / IAA-

  13. Arabidopsis CDS blastp result: AK072218 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK072218 J013167O21 At1g55350.4 calpain-type cysteine protease family identical to calpain...-like protein GI:20268660 from [Arabidopsis thaliana]; contains Pfam profiles: PF00648 Calpain family... cysteine protease, PF01067 Calpain large subunit,domain III; identical to cDNA calpain-like protein GI:20268659 1e-150 ...

  14. Arabidopsis CDS blastp result: AK287447 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287447 J043016O04 At2g46590.1 68415.m05811 Dof zinc finger protein DAG2 / Dof affecting germination... 2 (DAG2) identical to SP|Q9ZPY0 DOF zinc finger protein DAG2 (Dof affecting germination 2) {Arabidopsis thaliana} 2e-30 ...

  15. Arabidopsis CDS blastp result: AK103126 [KOME

    Lifescience Database Archive (English)

    Full Text Available 0S proteasome beta subunit PBB1 (PBB1) GB:AAC32066 [Arabidopsis thaliana] (Genetics 149 (2), 677-692 (1998)); contains Pfam profile: PF00227 proteasome A-type and B-type; 1e-129 ...

  16. Arabidopsis CDS blastp result: AK243298 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243298 J100053J04 At3g30290.1 68416.m03825 cytochrome P450 family protein similar to Cytochrom ... similar to GB:C71417 from [Arabidopsis thaliana] (Nature ... 391 (6666), 485-488 (1998)) 2e-44 ...

  17. Arabidopsis CDS blastp result: AK241385 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241385 J065156D02 At3g30290.1 68416.m03825 cytochrome P450 family protein similar to Cytochrom ... similar to GB:C71417 from [Arabidopsis thaliana] (Nature ... 391 (6666), 485-488 (1998)) 1e-11 ...

  18. Arabidopsis CDS blastp result: AK241333 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241333 J065144I22 At3g30290.1 68416.m03825 cytochrome P450 family protein similar to Cytochrom ... similar to GB:C71417 from [Arabidopsis thaliana] (Nature ... 391 (6666), 485-488 (1998)) 2e-35 ...

  19. Arabidopsis CDS blastp result: AK240730 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240730 J043030K09 At3g30290.1 68416.m03825 cytochrome P450 family protein similar to Cytochrom ... similar to GB:C71417 from [Arabidopsis thaliana] (Nature ... 391 (6666), 485-488 (1998)) 6e-11 ...

  20. Arabidopsis CDS blastp result: AK241521 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241521 J065170L14 At3g30290.1 68416.m03825 cytochrome P450 family protein similar to Cytochrom ... similar to GB:C71417 from [Arabidopsis thaliana] (Nature ... 391 (6666), 485-488 (1998)) 9e-32 ...

  1. Arabidopsis CDS blastp result: AK288402 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288402 J090030B22 At3g30290.1 68416.m03825 cytochrome P450 family protein similar to Cytochrom ... similar to GB:C71417 from [Arabidopsis thaliana] (Nature ... 391 (6666), 485-488 (1998)) 7e-25 ...

  2. Arabidopsis CDS blastp result: AK241581 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241581 J065181K09 At3g30290.1 68416.m03825 cytochrome P450 family protein similar to Cytochrom ... similar to GB:C71417 from [Arabidopsis thaliana] (Nature ... 391 (6666), 485-488 (1998)) 7e-12 ...

  3. Engineering calcium oxalate crystal formation in Arabidopsis

    Science.gov (United States)

    Many plants accumulate crystals of calcium oxalate. Just how these crystals form remains unknown. To gain insight into the mechanisms regulating calcium oxalate crystal formation, a crystal engineering approach was initiated utilizing the non-crystal accumulating plant, Arabidopsis. The success of t...

  4. Arabidopsis CDS blastp result: AK288349 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288349 J090023P19 At2g46590.1 68415.m05811 Dof zinc finger protein DAG2 / Dof affecting germination... 2 (DAG2) identical to SP|Q9ZPY0 DOF zinc finger protein DAG2 (Dof affecting germination 2) {Arabidopsis thaliana} 1e-23 ...

  5. Arabidopsis CDS blastp result: AK241364 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241364 J065152E11 At2g46590.1 68415.m05811 Dof zinc finger protein DAG2 / Dof affecting germination... 2 (DAG2) identical to SP|Q9ZPY0 DOF zinc finger protein DAG2 (Dof affecting germination 2) {Arabidopsis thaliana} 2e-20 ...

  6. Arabidopsis thaliana glucuronosyltransferase in family GT14.

    Science.gov (United States)

    Dilokpimol, Adiphol; Geshi, Naomi

    2014-01-01

    Arabinogalactan proteins are abundant cell-surface proteoglycans in plants and are involved in many cellular processes including somatic embryogenesis, cell-cell interactions, and cell elongation. We reported a glucuronosyltransferase encoded by Arabidopsis AtGlcAT14A, which catalyzes an addition of glucuronic acid residues to β-1,3- and β-1,6-linked galactans of arabinogalactan (Knoch et al. 2013). The knockout mutant of this gene resulted in the enhanced growth rate of hypocotyls and roots of seedlings, suggesting an involvement of AtGlcAT14A in cell elongation. AtGlcAt14A belongs to the family GT14 in the Carbohydrate Active Enzyme database (CAZy; www.cazy.org), in which a total of 11 proteins, including AtGLCAT14A, are classified from Arabidopsis thaliana. In this paper, we report the enzyme activities for the rest of the Arabidopsis GT14 isoforms, analyzed in the same way as for AtGlcAT14A. Evidently, two other Arabidopsis GT14 isoforms, At5g15050 and At2g37585, also possess the glucuronosyltransferase activity adding glucuronic acid residues to β-1,3- and β-1,6-linked galactans. Therefore, we named At5g15050 and At2g37585 as AtGlcAT14B and AtGlcAT14C, respectively. PMID:24739253

  7. Arabidopsis CDS blastp result: AK242817 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242817 J090063G17 At3g48560.1 68416.m05302 acetolactate synthase, chloroplast / acetohydroxy-a ... cid synthase (ALS ) nearly identical to SP|P17597 Acetolactate syntha ... ormerly EC 4.1.3.18) (Acetohydroxy-acid synthase) (ALS ) {Arabidopsis thaliana} 0.0 ...

  8. Arabidopsis CDS blastp result: AK058963 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK058963 001-020-C04 At3g48560.1 acetolactate synthase, chloroplast / acetohydroxy-acid synthase ... (ALS ) nearly identical to SP|P17597 Acetolactate syntha ... ormerly EC 4.1.3.18) (Acetohydroxy-acid synthase) (ALS ) {Arabidopsis thaliana} 2e-15 ...

  9. Arabidopsis CDS blastp result: AK109628 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK109628 002-138-C02 At3g48560.1 acetolactate synthase, chloroplast / acetohydroxy-acid synthase ... (ALS ) nearly identical to SP|P17597 Acetolactate syntha ... ormerly EC 4.1.3.18) (Acetohydroxy-acid synthase) (ALS ) {Arabidopsis thaliana} 0.0 ...

  10. Arabidopsis CDS blastp result: AK242722 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242722 J090045F10 At3g16857.2 68416.m02153 two-component responsive regulator fam...ily protein / response regulator family protein contains Pfam profile: PF00072 response regulator receiver domain; similar to... ARR1 protein GB:BAA74528 from [Arabidopsis thaliana] (Plant Cell Physiol. (1998) 39 (11), 1232-1239) 2e-22 ...

  11. Arabidopsis CDS blastp result: AK111864 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111864 J033025G23 At3g16857.2 two-component responsive regulator family protein / response regulato...r family protein contains Pfam profile: PF00072 response regulator receiver domain; similar to... ARR1 protein GB:BAA74528 from [Arabidopsis thaliana] (Plant Cell Physiol. (1998) 39 (11), 1232-1239) 1e-92 ...

  12. Arabidopsis CDS blastp result: AK241362 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241362 J065151H17 At3g16857.1 68416.m02152 two-component responsive regulator fam...ily protein / response regulator family protein contains Pfam profile: PF00072 response regulator receiver domain; similar to... ARR1 protein GB:BAA74528 from [Arabidopsis thaliana] (Plant Cell Physiol. (1998) 39 (11), 1232-1239) 5e-13 ...

  13. Arabidopsis CDS blastp result: AK112039 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK112039 001-044-C11 At3g16857.2 two-component responsive regulator family protein / response regulato...r family protein contains Pfam profile: PF00072 response regulator receiver domain; similar to... ARR1 protein GB:BAA74528 from [Arabidopsis thaliana] (Plant Cell Physiol. (1998) 39 (11), 1232-1239) 4e-18 ...

  14. Arabidopsis CDS blastp result: AK111899 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111899 J023034P21 At3g16857.2 two-component responsive regulator family protein / response regulato...r family protein contains Pfam profile: PF00072 response regulator receiver domain; similar to... ARR1 protein GB:BAA74528 from [Arabidopsis thaliana] (Plant Cell Physiol. (1998) 39 (11), 1232-1239) 1e-92 ...

  15. Arabidopsis CDS blastp result: AK242722 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242722 J090045F10 At3g16857.1 68416.m02152 two-component responsive regulator fam...ily protein / response regulator family protein contains Pfam profile: PF00072 response regulator receiver domain; similar to... ARR1 protein GB:BAA74528 from [Arabidopsis thaliana] (Plant Cell Physiol. (1998) 39 (11), 1232-1239) 2e-22 ...

  16. Arabidopsis CDS blastp result: AK241362 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241362 J065151H17 At3g16857.2 68416.m02153 two-component responsive regulator fam...ily protein / response regulator family protein contains Pfam profile: PF00072 response regulator receiver domain; similar to... ARR1 protein GB:BAA74528 from [Arabidopsis thaliana] (Plant Cell Physiol. (1998) 39 (11), 1232-1239) 5e-13 ...

  17. Arabidopsis CDS blastp result: AK119521 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK119521 001-202-D09 At3g57050.2 cystathionine beta-lyase, chloroplast / beta-cystathionase...thionase) (Cysteine lyase) {Arabidopsis thaliana} 1e-173 ... ... / cysteine lyase (CBL) identical to SP|P53780 Cystathionine beta-lyase, chloroplast precursor (EC 4.4.1.8) (CBL) (Beta-cysta

  18. Arabidopsis CDS blastp result: AK108403 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK108403 002-142-G06 At3g57050.2 cystathionine beta-lyase, chloroplast / beta-cystathionase...thionase) (Cysteine lyase) {Arabidopsis thaliana} 5e-36 ... ... / cysteine lyase (CBL) identical to SP|P53780 Cystathionine beta-lyase, chloroplast precursor (EC 4.4.1.8) (CBL) (Beta-cysta

  19. Arabidopsis CDS blastp result: AK065345 [KOME

    Lifescience Database Archive (English)

    Full Text Available cal over 405 amino acids to DYW7 protein of unknown function GB:CAA06829 from [Arabidopsis thaliana] (Plant...AK065345 J013008D19 At1g19720.1 pentatricopeptide (PPR) repeat-containing protein nearly identi... Mol. Biol. 42 (4), 603-613 (2000)); contains Pfam profile PF01535: PPR repeat 1e-87 ...

  20. Arabidopsis CDS blastp result: AK243514 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243514 J100075D15 At1g33280.1 68414.m04116 no apical meristem (NAM) family protein similar to ... CUC1 (GP:12060422) {Arabidopsis thaliana} amd ... to NAM (GP:1279640) {Petunia x hybrida} 7e-40 ...