268 research outputs found

    Interplay of Sugar, Light and Gibberellins in Expression of Rosa hybrida Vacuolar Invertase 1 Regulation

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    Our previous findings showed that the expression of the Rosa hybrida vacuolar invertase 1 gene (RhVI1) was tightly correlated with the ability of buds to grow out and was under sugar, gibberellin and light control. Here, we aimed to provide an insight into the mechanistic basis of this regulation. In situ hybridization showed that RhVI1 expression was localized in epidermal cells of young leaves of bursting buds. We then isolated a 895 bp fragment of the promoter of RhVI1. In silico analysis identified putative cis-elements involved in the response to sugars, light and gibberellins on its proximal part (595 bp). To carry out functional analysis of the RhVI1 promoter in a homologous system, we developed a direct method for stable transformation of rose cells. 5′ deletions of the proximal promoter fused to the uidA reporter gene were inserted into the rose cell genome to study the cell’s response to exogenous and endogenous stimuli. Deletion analysis revealed that the 468 bp promoter fragment is sufficient to trigger reporter gene activity in response to light, sugars and gibberellins. This region confers sucrose- and fructose-, but not glucose-, responsive activation in the dark. Inversely, the –595 to –468 bp region that carries the sugar-repressive element (SRE) is required to down-regulate the RhVI1 promoter in response to sucrose and fructose in the dark. We also demonstrate that sugar/light and gibberellin/light act synergistically to up-regulate β-glucuronidase (GUS) activity sharply under the control of the 595 bp pRhVI1 region. These results reveal that the 127 bp promoter fragment located between –595 and –468 bp is critical for light and sugar and light and gibberellins to act synergistically

    Covalent enzyme coupling on cellulose acetate membranes for glucose sensor development

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    International audienceMethods for immobilizing glucose oxidase (GOx) on cellulose acetate (CA) membranes are compared. The optimal method involves covalent coupling of bovine serum albumin (BSA) to CA membrane and a subsequent reaction of the membrane with GOx, which has previously been activated with an excess of p-benzoquinone. This coupling procedure is fairly reproducible and allows the preparation of thin membranes (5-20 µm) showing high surface activities (1-3 U/cm2) which are stable over a period of 1-3 months. Electrochemical and radiolabeling experiments show that enzyme inactivation as a result of immobilization is negligible. A good correlation between surface activity of membranes and their GOx load is observed

    WISEA J083011.95+283716.0: A Missing Link Planetary-Mass Object

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    We present the discovery of WISEA J083011.95+283716.0, the first Y dwarf candidate identified through the Backyard Worlds: Planet 9 citizen science project. We identified this object as a red, fast-moving source with a faint W2W2 detection in multi-epoch \textit{AllWISE} and unWISE images. We have characterized this object with Spitzer Space Telescope and \textit{Hubble Space Telescope} follow-up imaging. With mid-infrared detections in \textit{Spitzer}'s \emph{ch1} and \emph{ch2} bands and flux upper limits in Hubble Space Telescope F105WF105W and F125WF125W filters, we find that this object is both very faint and has extremely red colors (ch1−ch2=3.25±0.23ch1-ch2 = 3.25\pm0.23 mag, F125W−ch2≥9.36F125W-ch2 \geq 9.36 mag), consistent with a Teff∼300_{eff}\sim300 K source, as estimated from the known Y dwarf population. A preliminary parallax provides a distance of 11.1−1.5+2.011.1^{+2.0}_{-1.5} pc, leading to a slightly warmer temperature of ∼350\sim350 K. The extreme faintness and red Hubble Space Telescope and Spitzer Space Telescope colors of this object suggest it may be a link between the broader Y dwarf population and the coldest known brown dwarf WISE J0855−-0714, and highlight our limited knowledge of the true spread of Y dwarf colors. We also present four additional Backyard Worlds: Planet 9 late-T brown dwarf discoveries within 30 pc.Comment: 13 pages, 6 figures, 5 table

    WISEA J083011.95+283716.0: A Missing Link Planetary-mass Object

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    We present the discovery of WISEA J083011.95+283716.0, the first Y-dwarf candidate identified through the "Backyard Worlds: Planet 9" citizen science project. We identified this object as a red, fast-moving source with a faint W2 detection in multiepoch AllWISE and unWISE images. We have characterized this object with Spitzer and Hubble Space Telescope's (HST) follow-up imaging. With mid-infrared detections in Spitzer's ch1 and ch2 bands and flux upper limits in HST F105W and F125W filters, we find that this object is both very faint and has extremely red colors (ch1 − ch2 = 3.25 ± 0.23 mag, F125W − ch2 ≥ 9.36 mag), consistent with a T_(eff) ~ 300 K source, as estimated from the known Y-dwarf population. A preliminary parallax provides a distance of 11.1_(-1.5)^(+2.0) pc, leading to a slightly warmer temperature of ~350 K. The extreme faintness and red HST and Spitzer colors of this object suggest that it may be a link between the broader Y-dwarf population and the coldest known brown dwarf WISE J0855−0714, and may highlight our limited knowledge of the true spread of Y-dwarf colors. We also present four additional "Backyard Worlds: Planet 9" late-T brown dwarf discoveries within 30 pc

    A construção do mercado para o café em Alto Paraíso de Goiás.

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    Este estudo apresenta os principais resultados da análise de como habitantes de Alto Paraíso de Goiás estão buscando alternativas para o desenvolvimento sustentável do município, por meio da implantação, pela Embrapa, de projeto relativo ao resgate do café. A mineração e as atividades agropecuárias foram exercidas na região até os anos 60, quando a atividade principal passou a ser o turismo, a partir da criação do Parque Nacional da Chapada dos Veadeiros e da inauguração de Brasília. Em 2000, o fluxo de turistas decaiu devido a problemas relativos à saúde pública, acarretando estagnação da economia local. Nos últimos anos, produtores familiares despertaram para a existência, ali, de um café que pode ser comercializado em nichos de mercado de grãos especiais: orgânicos e de origem definida, e buscaram, na Embrapa, o desenvolvimento de projeto de pesquisa. O estudo na região revelou que por meio do desvelamento de valores - história, cultura e tradições - é possível estabelecer estratégia mais eficiente de busca de mercado, a partir da experiência revelada no trabalho concreto e na cultura dos produtores. E que o desenvolvimento rural deve ser buscado por meio do desenvolvimento de atividades da nova ruralidade e da aplicação de abordagem territorial de desenvolvimento
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