nifH pyrosequencing reveals the potential for location-specific soil chemistry to influence N2-fixing community dynamics

A dataset of 87 020 nifH reads and 16 782 unique nifH protein sequences obtained over 2 years from four locations across a gradient of agricultural soil types in Argentina were analysed to provide a detailed and comprehensive picture of the diversity, abundance and responses of the N2-fixing community in relation to differences in soil chemistry and agricultural practices. Phylogenetic analysis revealed an expected high proportion of Alphaproteobacteria, Betaproteobacteria and Deltaproteobacteria, mainly relatives to Bradyrhizobium and Methylosinus/Methylocystis, but a surprising paucity of Gammaproteobacteria. Analysis of variance and stepwise regression modelling suggested location and treatment-specific influences of soil type on diazotrophic community composition and organic carbon concentrations on nifH diversity. nifH gene abundance, determined by quantitative real-time polymerase chain reaction, was higher in agricultural soils than in non-agricultural soils, and was influenced by soil chemistry under intensive crop rotation but not under monoculture. At some locations, sustainable increased crop yields might be possible through the management of soil chemistry to improve the abundance and diversity of N2-fixing bacteriaFil: Collavino, Mónica Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Tripp, H. James. University of California. Department of Ocean Sciences; Estados UnidosFil: Frank, Ildiko E.. University of California. Department of Ocean Sciences; Estados UnidosFil: Vidoz, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); ArgentinaFil: Calderoli, Priscila Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Donato, Mariano Humberto. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Sistemática y Biología Evolutiva; ArgentinaFil: Zehr, Jonathan P.. University of California. Department of Ocean Sciences; Estados UnidosFil: Aguilar, Orlando Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Biotecnología y Biología Molecular; Argentin

nifH pyrosequencing reveals the potential for location-specific soil chemistry to influence N₂-fixing community dynamics

A dataset of 87 020 nifH reads and 16 782 unique nifH protein sequences obtained over 2 years from four locations across a gradient of agricultural soil types in Argentina were analysed to provide a detailed and comprehensive picture of the diversity, abundance and responses of the N₂-fixing community in relation to differences in soil chemistry and agricultural practices. Phylogenetic analysis revealed an expected high proportion of Alphaproteobacteria, Betaproteobacteria and Deltaproteobacteria, mainly relatives to Bradyrhizobium and Methylosinus/Methylocystis, but a surprising paucity of Gammaproteobacteria. Analysis of variance and stepwise regression modelling suggested location and treatment-specific influences of soil type on diazotrophic community composition and organic carbon concentrations on nifH diversity. nifH gene abundance, determined by quantitative real-time polymerase chain reaction, was higher in agricultural soils than in non-agricultural soils, and was influenced by soil chemistry under intensive crop rotation but not under monoculture. At some locations, sustainable increased crop yields might be possible through the management of soil chemistry to improve the abundance and diversity of N₂-fixing bacteria.Facultad de Ciencias ExactasInstituto de Biotecnologia y Biologia MolecularFacultad de Ciencias Naturales y MuseoLaboratorio de Sistemática y Biología Evolutiv

nifH pyrosequencing reveals the potential for location-specific soil chemistry to influence N2 -fixing community dynamics.

A dataset of 87 020 nifH reads and 16 782 unique nifH protein sequences obtained over 2 years from four locations across a gradient of agricultural soil types in Argentina were analysed to provide a detailed and comprehensive picture of the diversity, abundance and responses of the N2 -fixing community in relation to differences in soil chemistry and agricultural practices. Phylogenetic analysis revealed an expected high proportion of Alphaproteobacteria, Betaproteobacteria and Deltaproteobacteria, mainly relatives to Bradyrhizobium and Methylosinus/Methylocystis, but a surprising paucity of Gammaproteobacteria. Analysis of variance and stepwise regression modelling suggested location and treatment-specific influences of soil type on diazotrophic community composition and organic carbon concentrations on nifH diversity. nifH gene abundance, determined by quantitative real-time polymerase chain reaction, was higher in agricultural soils than in non-agricultural soils, and was influenced by soil chemistry under intensive crop rotation but not under monoculture. At some locations, sustainable increased crop yields might be possible through the management of soil chemistry to improve the abundance and diversity of N2 -fixing bacteria

Do large femoral heads reduce the risks of impingement in total hip arthroplasty with optimal and non-optimal cup positioning?

The purpose of this study was to assess whether large femoral heads (36–38 mm) improve the range of motion in total hip arthroplasty compared to standard (28–32 mm) femoral heads in the presence of optimal and non-optimal cup positioning. A mathematical model of the hip joint was generated by using a laser scan of a dried cadaveric hip. The range of motion was assessed with a cup inclination and anteversion of reference and with non-optimal cup positions. Large femoral heads increased the range of motion, compared to the 28-mm femoral head, in the presence of a hip prosthesis correctly implanted and even more so in the presence of non-optimal cup positioning. However, with respect to the 32-mm femoral head, large femoral heads showed limited benefits both in the presence of optimal and non-optimal cup positioning