56 research outputs found

    Quantitative trait loci (QTLs) analysis of palm oil fatty acid composition in an interspecific pseudo-backcross from Elaeis oleifera (HBK) Cort,s and oil palm (Elaeis guineensis Jacq.)

    Get PDF
    IATE Axe 4 : Biotechnologie microbienne et enzymatique des lipides et des agropolymèresWe chose an Elaeis interspecific pseudo-backcross of first generation (E. oleifera x E. guineensis) x E. guineensis to identify quantitative trait loci (QTLs) for fatty acid composition of palm oil. A dense microsatellite linkage map of 362 loci spanned 1.485 cM, representing the 16 pairs of homologous chromosomes in the Elaeis genus from which we traced segregating alleles from both E. oleifera and E. guineensis grandparents. The relative linear orders of mapped loci suggested the probable absence of chromosome rearrangements between the E. oleifera and E. guineensis genomes. A total of 19 QTL associated to the palm oil fatty acid composition were evidenced. The QTL positions and the species origin as well as the estimated effects of the QTL marker alleles were in coherence with the knowledge of the oil biosynthesis pathway in plants and with the individual phenotypic correlations between the traits. The mapping of chosen Elaeis key genes related to oleic acid C18:1, using intra-gene SNPs, supported several QTLs underlying notably FATA and SAD enzymes. The high number of hyper-variable SSR loci of known relative linear orders and the QTL information make these resources valuable for such mapping study in other Elaeis breeding materials

    A reference microsatellite kit to assess for genetic diversity of Sorghum bicolor (Poaceae)

    Get PDF
    Premise of the study: Discrepancies in terms of genotyping data are frequently observed when comparing simple sequence repeat (SSR) data sets across genotyping technologies and laboratories. This technical concern introduces biases that hamper any synthetic studies or comparison of genetic diversity between collections. To prevent this for Sorghum bicolor, we developed a control kit of 48 SSR markers. • Methods and Results: One hundred seventeen markers were selected along the genome to provide coverage across the length of all 10 sorghum linkage groups. They were tested for polymorphism and reproducibility across two laboratories (Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement [CIRAD], France, and International Crops Research Institute for the Semi-Arid Tropics [ICRISAT], India) using two commonly used genotyping technologies (polyacrylamide gel–based technology with LI-COR sequencing machines and capillary systems with ABI sequencing apparatus) with DNA samples from a diverse set of 48 S. bicolor accessions. • Conclusions: A kit for diversity analysis (http://sat.cirad.fr/sat/sorghum_SSR_kit/) was developed. It contains information on 48 technically robust sorghum microsatellite markers and 10 DNA controls. It can further be used to calibrate sorghum SSR genotyping data acquired with different technologies and compare those to genetic diversity reference

    Effects of marital/dependency status on reenlistment behavior of second-term enlisted females.

    Get PDF
    This thesis investigates the relationship of reenlistment decisions of second-term enlisted women in the military to their marital and dependent status, using individual-level data from the 1985 DoD Survey of Officer and Enlisted Personnel. Actual reenlistment status (December 1988) of each survey respondent was merged with the data set. Logit analysis was used to estimate the likelihood of a respondent choosing to reenlist given her set of individual characteristics. Separate logit models were estimated for the following groups of second-term personnel: single women without children, single women with children, married women without children, and married women with children. Certain variables affected all groups similarly (pay grade, minority status, perception of civilian job alternatives). Others exerted differential impact on subgroups (job satisfaction, traditionality of job). Results illustrated differential reenlistment behavior based upon the presence of children. Results may be used to target reenlistment incentives for specified marital/dependent status groups.http://archive.org/details/effectsofmarital00edwaLieutenant, United States NavyApproved for public release; distribution is unlimited

    Massive Sorghum Collection Genotyped with SSR Markers to Enhance Use of Global Genetic Resources

    Get PDF
    Large ex situ collections require approaches for sampling manageable amounts of germplasm for in-depth characterization and use. We present here a large diversity survey in sorghum with 3367 accessions and 41 reference nuclear SSR markers. Of 19 alleles on average per locus, the largest numbers of alleles were concentrated in central and eastern Africa. Cultivated sorghum appeared structured according to geographic regions and race within region. A total of 13 groups of variable size were distinguished. The peripheral groups in western Africa, southern Africa and eastern Asia were the most homogeneous and clearly differentiated. Except for Kafir, there was little correspondence between races and marker-based groups. Bicolor, Caudatum, Durra and Guinea types were each dispersed in three groups or more. Races should therefore better be referred to as morphotypes. Wild and weedy accessions were very diverse and scattered among cultivated samples, reinforcing the idea that large gene-flow exists between the different compartments. Our study provides an entry to global sorghum germplasm collections. Our reference marker kit can serve to aggregate additional studies and enhance international collaboration. We propose a core reference set in order to facilitate integrated phenotyping experiments towards refined functional understanding of sorghum diversity

    Generation of subnanometric platinum with high stability during transformation of a 2D zeolite into 3D

    Get PDF
    [EN] Single metal atoms and metal clusters have attracted much attention thanks to their advantageous capabilities as heterogeneous catalysts. However, the generation of stable single atoms and clusters on a solid support is still challenging. Herein, we report a new strategy for the generation of single Pt atoms and Pt clusters with exceptionally high thermal stability, formed within purely siliceous MCM-22 during the growth of a two-dimensional zeolite into three dimensions. These subnanometric Pt species are stabilized by MCM-22, even after treatment in air up to 540 degrees C. Furthermore, these stable Pt species confined within internal framework cavities show size-selective catalysis for the hydrogenation of alkenes. High-temperature oxidation-reduction treatments result in the growth of encapsulated Pt species to small nanoparticles in the approximate size range of 1 to 2 nm. The stability and catalytic activity of encapsulated Pt species is also reflected in the dehydrogenation of propane to propylene.This work was funded by the Spanish Government (Consolider Ingenio 2010-MULTICAT (CSD2009-00050) and MAT2014-52085-C2-1-P) and by the Generalitat Valenciana (Prometeo). The Severo Ochoa Program (SEV-2012-0267) is gratefully acknowledged. L.L. thanks ITQ for a contract. The authors also thank the Microscopy Service of UPV for the TEM and STEM measurements. The HAADF-HRSTEM works were conducted in the Laboratorio de Microscopias Avanzadas (LMA) at the Instituto de Nanociencia de Aragon (INA)-Universidad de Zaragoza (Spain), a Spanish ICTS National Facility. Some of the research leading to these results has received funding from the European Union Seventh Framework Program under Grant Agreement 312483-ESTEEM2 (Integrated Infrastructure Initiative-I3). R.A. also acknowledges funding from the Spanish Ministerio de Economia y Competitividad (FIS2013-46159-C3-3-P) and the European Union Horizon 2020 research and innovation programme under the Marie Sldodowska-Curie grant agreement No. 642742.Liu, L.; Díaz Morales, UM.; Arenal, R.; Agostini, G.; Concepción Heydorn, P.; Corma Canós, A. (2017). Generation of subnanometric platinum with high stability during transformation of a 2D zeolite into 3D. Nature Materials. 16(1):132-138. https://doi.org/10.1038/NMAT4757S132138161Boronat, M., Leyva-Perez, A. & Corma, A. Theoretical and experimental insights into the origin of the catalytic activity of subnanometric gold clusters: attempts to predict reactivity with clusters and nanoparticles of gold. Acc. Chem. Res. 47, 834–844 (2014).Flytzani-Stephanopoulos, M. & Gates, B. C. Atomically dispersed supported metal catalysts. Ann. Rev. Chem. Bio. Eng. 3, 545–574 (2012).Gates, B. C. Supported metal clusters: synthesis, structure, and catalysis. Chem. Rev. 95, 511–522 (1995).Corma, A. et al. Exceptional oxidation activity with size-controlled supported gold clusters of low atomicity. Nat. Chem. 5, 775–781 (2013).Yang, M. et al. Catalytically active Au-O(OH)x-species stabilized by alkali ions on zeolites and mesoporous oxides. Science 346, 1498–1501 (2014).Rivallan, M. et al. Platinum sintering on H-ZSM-5 followed by chemometrics of CO adsorption and 2D pressure-jump IR spectroscopy of adsorbed species. Angew. Chem. Int. Ed. 49, 785–789 (2010).Zecevic, J., van der Eerden, A. M., Friedrich, H., de Jongh, P. E. & de Jong, K. P. Heterogeneities of the nanostructure of platinum/zeolite Y catalysts revealed by electron tomography. ACS Nano 7, 3698–3705 (2013).Philippaerts, A. et al. Unprecedented shape selectivity in hydrogenation of triacylglycerol molecules with Pt/ZSM-5 zeolite. Angew. Chem. Int. Ed. 50, 3947–3949 (2011).Kim, J., Kim, W., Seo, Y., Kim, J.-C. & Ryoo, R. n-Heptane hydroisomerization over Pt/MFI zeolite nanosheets: effects of zeolite crystal thickness and platinum location. J. Catalys. 301, 187–197 (2013).Goel, S., Wu, Z., Zones, S. I. & Iglesia, E. Synthesis and catalytic properties of metal clusters encapsulated within small-pore (SOD, GIS, ANA) zeolites. J. Am. Chem. Soc. 134, 17688–17695 (2012).Choi, M., Wu, Z. & Iglesia, E. Mercaptosilane-assisted synthesis of metal clusters within zeolites and catalytic consequences of encapsulation. J. Am. Chem. Soc. 132, 9129–9137 (2010).Choi, M., Yook, S. & Kim, H. Hydrogen spillover in encapsulated metal catalysts: new opportunities for designing advanced hydroprocessing catalysts. ChemCatChem 7, 1048–1057 (2015).Kulkarni, A., Lobo-Lapidus, R. J. & Gates, B. C. Metal clusters on supports: synthesis, structure, reactivity, and catalytic properties. Chem. Commun. 46, 5997–6015 (2010).Guzman, J. & Gates, B. C. Supported molecular catalysts: metal complexes and clusters on oxides and zeolites. Dalton Trans. 1, 3303–3318 (2003).Leonowicz, M. E., Lawton, J. A., Lawton, S. L. & Rubin, M. K. MCM-22: a molecular sieve with two independent multidimensional channel systems. Science 264, 1910–1913 (1994).Camblor, M. A. et al. A new microporous polymorph of silica isomorphous to zeolite MCM-22. Chem. Mater. 8, 2415–2417 (1996).Hyotanishi, M., Isomura, Y., Yamamoto, H., Kawasaki, H. & Obora, Y. Surfactant-free synthesis of palladium nanoclusters for their use in catalytic cross-coupling reactions. Chem. Commun. 47, 5750–5752 (2011).Duchesne, P. N. & Zhang, P. Local structure of fluorescent platinum nanoclusters. Nanoscale 4, 4199–4205 (2012).Lu, J., Aydin, C., Browning, N. D. & Gates, B. C. Imaging isolated gold atom catalytic sites in zeolite NaY. Angew. Chem. Int. Ed. 51, 5842–5846 (2012).Yacamán, M. J., Santiago, U. & Mejía-Rosales, S. in Advanced Transmission Electron Microscopy: Applications to Nanomaterials (eds Francis, L., Mayoral, A. & Arenal, R.) 1–29 (Springer, 2015).Jena, P., Khanna, S. N. & Rao, B. K. Physics and Chemistry of Finite Systems: From Clusters to Crystals (Springer, 1992).Yamasaki, J. et al. Ultramicroscopy 151, 224–231 (2015).Sohlberg, K., Pennycook, T. J., Zhoud, W. & Pennycook, S. J. Insights into the physical chemistry of materials from advances in HAADF-STEM. Phys. Chem. Chem. Phys. 17, 3982–4006 (2015).Aydin, C., Lu, J., Browning, N. D. & Gates, B. C. A ‘smart’ catalyst: sinter-resistant supported iridium clusters visualized with electron microscopy. Angew. Chem. Int. Ed. 51, 5929–5934 (2012).Wei, H. et al. FeOx-supported platinum single-atom and pseudo-single-atom catalysts for chemoselective hydrogenation of functionalized nitroarenes. Nat. Commun. 5, 5634 (2014).Addou, R. et al. Influence of hydroxyls on Pd atom mobility and clustering on rutile TiO2(011)-2 × 1. ACS Nano 8, 6321–6333 (2014).Jung, U. et al. Comparative in operando studies in heterogeneous catalysis: atomic and electronic structural features in the hydrogenation of ethylene over supported Pd and Pt catalysts. ACS Catal. 5, 1539–1551 (2015).Agostini, G. et al. Effect of different face centered cubic nanoparticle distributions on particle size and surface area determination: a theoretical study. J. Phys. Chem. C 118, 4085–4094 (2014).Alexeev, O. & Gates, B. C. EXAFS characterization of supported metal-complex and metal-cluster catalysts made from organometallic precursors. Top. Catal. 10, 273–293 (2000).Chakraborty, I., Bhuin, R. G., Bhat, S. & Pradeep, T. Blue emitting undecaplatinum clusters. Nanoscale 6, 8561–8564 (2014).Zheng, J., Nicovich, P. R. & Dickson, R. M. Highly fluorescent noble-metal quantum dots. Ann. Rev. Phys. Chem. 58, 409–431 (2007).Okrut, A. et al. Selective molecular recognition by nanoscale environments in a supported iridium cluster catalyst. Nat. Nanotech. 9, 459–465 (2014).Zhou, C. et al. On the sequential hydrogen dissociative chemisorption on small platinum clusters: a density functional theory study. J. Phys. Chem. C 111, 12773–12778 (2007).De La Cruz, C. & Sheppard, N. An exploration of the surfaces of some Pt/SiO2 catalysts using CO as an infrared spectroscopic probe. Spectrochim. Acta A 50, 271–285 (1994).Klünker, C., Balden, M., Lehwald, S. & Daum, W. CO stretching vibrations on Pt(111) and Pt(110) studied by sum frequency generation. Surf. Sci. 360, 104–111 (1996).Stakheev, A. Y., Shpiro, E. S., Jaeger, N. I. & Schulz-Ekloff, G. Electronic state and location of Pt metal clusters in KL zeolite: FTIR study of CO chemisorption. Catal. Lett. 32, 147–158 (1995).Heiz, U., Sanchez, A., Abbet, S. & Schneider, W. D. Catalytic oxidation of carbon monoxide on monodispersed platinum clusters: each atom counts. J. Am. Chem. Soc. 121, 3214–3217 (1999).Levitas, V. I. & Samani, K. Size and mechanics effects in surface-induced melting of nanoparticles. Nat. Commun. 2, 284 (2011).Jiang, H., Moon, K.-s., Dong, H., Hua, F. & Wong, C. P. Size-dependent melting properties of tin nanoparticles. Chem. Phys. Lett. 429, 492–496 (2006).Nanda, K. K., Kruis, F. E. & Fissan, H. Evaporation of free PbS nanoparticles: evidence of the Kelvin effect. Phys. Rev. Lett. 89, 256103 (2002).Vajda, S. et al. Subnanometre platinum clusters as highly active and selective catalysts for the oxidative dehydrogenation of propane. Nat. Mater. 8, 213–216 (2009).Ortalan, V., Uzun, A., Gates, B. C. & Browning, N. D. Direct imaging of single metal atoms and clusters in the pores of dealuminated HY zeolite. Nat. Nanotech. 5, 506–510 (2010).Koch, C. Determination of Core Structure Periodicity and Point Defect Density along Dislocations PhD thesis, Univ. Arizona (2002).Mathon, O. et al. The time-resolved and extreme conditions XAS (TEXAS) facility at the European Synchrotron Radiation Facility: the general-purpose EXAFS bending-magnet beamline BM23. J. Synchrotron Radiat. 22, 1548–1554 (2015).Newville, M. IFEFFIT: interactive XAFS analysis and FEFF fitting. J. Synchrotron Radiat. 8, 322–324 (2001)

    Foundation characteristics of edible Musa triploids revealed from allelic distribution of SSR markers

    Get PDF
    Background and Aims The production of triploid banana and plantain (Musa spp.) cultivars with improved characteristics (e.g. greater disease resistance or higher yield), while still preserving the main features of current popular cultivars (e.g. taste and cooking quality), remains a major challenge for Musa breeders. In this regard, breeders require a sound knowledge of the lineage of the current sterile triploid cultivars, to select diploid parents that are able to transmit desirable traits, together with a breeding strategy ensuring final triploidization and sterility. Highly polymorphic single sequence repeats (SSRs) are valuable markers for investigating phylogenetic relationships. Methods Here, the allelic distribution of each of 22 SSR loci across 561 Musa accessions is analysed. Key Results and ConclusionsWe determine the closest diploid progenitors of the triploid 'Cavendish' and 'Gros Michel' subgroups, valuable information for breeding programmes. Nevertheless, in establishing the likely monoclonal origin of the main edible triploid banana subgroups (i.e. 'Cavendish', 'Plantain' and 'Mutika- Lujugira'), we postulated that the huge phenotypic diversity observed within these subgroups did not result from gamete recombination, but rather from epigenetic regulations. This emphasizes the need to investigate the regulatory mechanisms of genome expression on a unique model in the plant kingdom. We also propose experimental standards to compare additional and independent genotyping data for reference. (Résumé d'auteur

    Genetic Structure, Linkage Disequilibrium and Signature of Selection in Sorghum: Lessons from Physically Anchored DArT Markers

    Get PDF
    Population structure, extent of linkage disequilibrium (LD) as well as signatures of selection were investigated in sorghum using a core sample representative of worldwide diversity. A total of 177 accessions were genotyped with 1122 informative physically anchored DArT markers. The properties of DArTs to describe sorghum genetic structure were compared to those of SSRs and of previously published RFLP markers. Model-based (STRUCTURE software) and Neighbor-Joining diversity analyses led to the identification of 6 groups and confirmed previous evolutionary hypotheses. Results were globally consistent between the different marker systems. However, DArTs appeared more robust in terms of data resolution and bayesian group assignment. Whole genome linkage disequilibrium as measured by mean r2 decreased from 0.18 (between 0 to 10 kb) to 0.03 (between 100 kb to 1 Mb), stabilizing at 0.03 after 1 Mb. Effects on LD estimations of sample size and genetic structure were tested using i. random sampling, ii. the Maximum Length SubTree algorithm (MLST), and iii. structure groups. Optimizing population composition by the MLST reduced the biases in small samples and seemed to be an efficient way of selecting samples to make the best use of LD as a genome mapping approach in structured populations. These results also suggested that more than 100,000 markers may be required to perform genome-wide association studies in collections covering worldwide sorghum diversity. Analysis of DArT markers differentiation between the identified genetic groups pointed out outlier loci potentially linked to genes controlling traits of interest, including disease resistance genes for which evidence of selection had already been reported. In addition, evidence of selection near a homologous locus of FAR1 concurred with sorghum phenotypic diversity for sensitivity to photoperiod
    corecore