Phosphorus analysis in soil under herbaceous perennial leguminous cover by nuclear magnetic spectroscopy

The availability and the reserves of organic phosphorus are controlled by its mineralization rate and are also influenced by changes in soil management. The objective of this study was to evaluate the influence of soil covering with different leguminous plant on soil organic P by 31P-NMR spectroscopy. Alkaline soil extracts were obtained from two depths (0-5 and 5-10 cm) of an Ultisol cultivated with herbaceous perennial leguminous plants (Arachis pintoi, Pueraria phaseoloides, Macroptilium atropurpureum). In an adjacent area, samples of the same soil cover with a secondary tropical forest and grass (Panicum maximum) were also collected. The leguminous management was divided into with removal and without removal of shoot parts after cut on soil surface. Phosphate monoesters are the dominant P species in all soil samples and P diesters accumulated on the superficial layer of secondary forest soil. The P amount of this fraction is higher for the legume covered soil when compared with the grass covered soil. The permanence of leguminous plants on the topsoil after the cut promoted an increase in P diester/P monoester ratios. These findings can be accounted for an enhancement of P availability to plants in soils cultivated with leguminous plants.

Chemical probes that differentially modulate peroxisome proliferator-activated receptor alpha and BLTR, nuclear and cell surface receptors for leukotriene B(4).

Peroxisome proliferator-activated receptor alpha (PPARalpha)is a nuclear receptor for various fatty acids, eicosanoids, and hypolipidemic drugs. In the presence of ligand, this transcription factor increases expression of target genes that are primarily associated with lipid homeostasis. We have previously reported PPARalpha as a nuclear receptor of the inflammatory mediator leukotriene B(4) (LTB(4)) and demonstrated an anti-inflammatory function for PPARalpha in vivo (Devchand, P. R., Keller, H., Peters, J. M., Vazquez, M., Gonzalez, F. J., and Wahli, W. (1996) Nature 384, 39-43). LTB(4) also has a cell surface receptor (BLTR) that mediates proinflammatory events, such as chemotaxis and chemokinesis (Yokomizo, T., Izumi, T., Chang, K., Takuwa, Y., and Shimizu, T. (1997) Nature 387, 620-624). In this study, we report on chemical probes that differentially modulate activity of these two LTB(4) receptors. The compounds selected were originally characterized as synthetic BLTR effectors, both agonists and antagonists. Here, we evaluate the compounds as effectors of the three PPAR isotypes (alpha, beta, and gamma) by transient transfection assays and also determine whether the compounds are ligands for these nuclear receptors by coactivator-dependent receptor ligand interaction assay, a semifunctional in vitro assay. Because the compounds are PPARalpha selective, we further analyze their potency in a biological assay for the PPARalpha-mediated activity of lipid accumulation. These chemical probes will prove invaluable in dissecting processes that involve nuclear and cell surface LTB(4) receptors and also aid in drug discovery programs.

WISE: Women in Science and Engineering, Fall 2006

Women in Science and Engineering (WISE) Program is to expand and improve educational and professional opportunities for women in all fields of science, technology, engineering and math (STEM) by facilitating individual, institutional, and social change.

WISE: Women in Science and Engineering, Spring 2007

Women in Science and Engineering (WISE) Program is to expand and improve educational and professional opportunities for women in all fields of science, technology, engineering and math (STEM) by facilitating individual, institutional, and social change.

WISE: Women in Science and Engineering, Spring 2009

Women in Science and Engineering (WISE) Program is to expand and improve educational and professional opportunities for women in all fields of science, technology, engineering and math (STEM) by facilitating individual, institutional, and social change.

WISE: Women in Science and Engineering, Winter 2007

Women in Science and Engineering (WISE) Program is to expand and improve educational and professional opportunities for women in all fields of science, technology, engineering and math (STEM) by facilitating individual, institutional, and social change.

WISE: Women in Science and Engineering, Winter 2007-2008

Women in Science and Engineering (WISE) Program is to expand and improve educational and professional opportunities for women in all fields of science, technology, engineering and math (STEM) by facilitating individual, institutional, and social change.

WISE: Women in Science and Engineering, Winter 2009

Women in Science and Engineering (WISE) Program is to expand and improve educational and professional opportunities for women in all fields of science, technology, engineering and math (STEM) by facilitating individual, institutional, and social change.

WISE: Women in Science and Engineering, Winter 2011-2012

Women in Science and Engineering (WISE) Program is to expand and improve educational and professional opportunities for women in all fields of science, technology, engineering and math (STEM) by facilitating individual, institutional, and social change.

Integrating nuclear receptor mobility in models of gene regulation.

The mode of action of nuclear receptors in living cells is an actively investigated field but much remains hypothetical due to the lack, until recently, of methods allowing the assessment of molecular mechanisms in vivo. However, these last years, the development of fluorescence microscopy methods has allowed initiating the dissection of the molecular mechanisms underlying gene regulation by nuclear receptors directly in living cells or organisms. Following our analyses on peroxisome proliferator activated receptors (PPARs) in living cells, we discuss here the different models arising from the use of these tools, that attempt to link mobility, DNA binding or chromatin interaction, and transcriptional activity.

Dessalinització nuclear : estudi preliminar per l'aplicació a Catalunya

Aquest document pretén donar a conèixer el concepte de dessalinització nuclear, determinar els avantatges i inconvenients a nivell ambiental, així com els costos econòmics i energètics que poden suposar. Podem definir dessalinització nuclear com una planta de dessalinització d’aigua marina que és alimentada pel seu complet funcionament per un reactor nuclear. La planta utilitza tant l’energia elèctrica que es produeix com l’energia calorífica retinguda en l’aigua que surt del reactor. S’ha estructurat el treball en tres parts. La primera és una anàlisi de quin és l’ús que se’n fa a nivell mundial de la tecnologia de dessalinització. S’ofereixen dades de la producció mundial d’aigua dolça a partir d’aquesta tecnologia, en quins països se’n fa més ús i perquè. També es defineixen els tipus de plantes de dessalinització que es poden construir. El segon apartat és un anàlisi històric i d’actualitat de la dessalinització nuclear mundial. S’analitza el perquè del desenvolupament d’aquesta tecnologia i s’estudien les necessitats hídriques que es podran tenir en un futur. Es planteja si aquesta tecnologia pot satisfer-les. S’estudien les onze plantes de dessalinització nuclear que han funcionat. El tercer apartat és un estudi de la possible transformació de les dues plantes dessalinitzadores catalanes en dessalinitzadores nuclears. Es fa un anàlisi de costos energètics i de producció, sense tenir en compte els d’instal·lació. També s’investiga els possibles impactes per contaminació radiològica que podria generar l’aigua produïda amb aquesta tecnologia.

Construção de uma coleção nuclear de arroz para o Brasil

A coleção de germoplasma de arroz da Embrapa consiste aproximadamente de 10.000 acessos. O objetivo desse trabalho foi estabelecer a Coleção Nuclear (CN) dessa coleção utilizando as informações e dados disponíveis sobre seus acessos. A estratégia CN foi introduzida no manejo de recursos genéticos vegetais com o principal objetivo de ampliar e sistematizar o uso desses recursos. Uma CN deve ser selecionada procurando reter a variabilidade genética existente na coleção inteira (CI) com um mínimo de redundância. Os acessos da coleção de arroz foram classificados em três estratos: a) variedades tradicionais do Brasil (VT); b) linhagens/cultivares melhoradas do Brasil (LCM); e c) linhagens/cultivares introduzidas (LCI). As variedades tradicionais foram ainda classificadas segundo o sistema de cultivo (terras altas, várzeas e facultativo). Os três estratos foram representados na Coleção Nuclear, mas ênfase maior foi dada às variedades tradicionais, que constituíram 308 acessos. Os acessos foram alocados para cada sistema de cultivo, proporcionalmente ao produto do logarítmo do número de variedades tradicionais pelo índice de Shannon (medida de diversidade) de cada um deles. A seleção dos acessos foi feita com o auxilio do Sistema de Informação Geográfica (SIG). A CN brasileira de arroz está formada por 550 acessos.

Phylogenetics of Olea (Oleaceae) based on plastid and nuclear ribosomal DNA sequences: tertiary climatic shifts and lineage differentiation times.

BACKGROUND AND AIMS: The genus Olea (Oleaceae) includes approx. 40 taxa of evergreen shrubs and trees classified in three subgenera, Olea, Paniculatae and Tetrapilus, the first of which has two sections (Olea and Ligustroides). Olive trees (the O. europaea complex) have been the subject of intensive research, whereas little is known about the phylogenetic relationships among the other species. To clarify the biogeographical history of this group, a molecular analysis of Olea and related genera of Oleaceae is thus necessary. METHODS: A phylogeny was built of Olea and related genera based on sequences of the nuclear ribosomal internal transcribed spacer-1 and four plastid regions. Lineage divergence and the evolution of abaxial peltate scales, the latter character linked to drought adaptation, were dated using a Bayesian method. KEY RESULTS: Olea is polyphyletic, with O. ambrensis and subgenus Tetrapilus not sharing a most recent common ancestor with the main Olea clade. Partial incongruence between nuclear and plastid phylogenetic reconstructions suggests a reticulation process in the evolution of subgenus Olea. Estimates of divergence times for major groups of Olea during the Tertiary were obtained. CONCLUSIONS: This study indicates the necessity of revising current taxonomic boundaries in Olea. The results also suggest that main lines of evolution were promoted by major Tertiary climatic shifts: (1) the split between subgenera Olea and Paniculatae appears to have taken place at the Miocene-Oligocene boundary; (2) the separation of sections Ligustroides and Olea may have occurred during the Early Miocene following the Mi-1 glaciation; and (3) the diversification within these sections (and the origin of dense abaxial indumentum in section Olea) was concomitant with the aridification of Africa in the Late Miocene.