172 research outputs found

    Physiological and enzymatic changes in rice seeds stored at low temperatures

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    This study aimed to evaluate the effect of low temperatures on the physiological and enzymatic changes of rice seeds. The seeds were packed in airtight chambers and maintained at temperatures of 8 and -50°C for periods of 15, 30 , 45, 60, 75 and 90 days. The same procedure was adopted for the control treatment with the seeds  kept at a temperature of 25°C. The seeds were evaluated regarding germination test; seedling emergency;  emergency speed index; length and dry weight of radicle; and seedling of shoot. The activity of amylase and  total protein content were also evaluated. The temperatures of 8 and -50°C significantly influenced the  physiological quality and the enzyme amylase activity of rice seeds, resulting in higher germination, seedling  emergence and enzyme activity. The temperature is a promising alternative for the maintenance of  physiological quality and enzymatic activity of rice seeds during storage. Key words: Oryza sativa L., enzymatic activity, physiological quality, storage.Abbreviation: ESI, Emergence speed index; PVP, polyvinylpyrrolidone

    Identification of eight solanum (subgenus Leptostemonum) species as novel natural hosts of tomato chlorosis virus in Brazil.

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    Made available in DSpace on 2018-10-20T00:41:01Z (GMT). No. of bitstreams: 1 apsjournals.apsnet.orgIdentificationofEightSolanumsubgenusLeptostemonumSpeciesasNovelNaturalHostsofTomatochlor.pdf: 185191 bytes, checksum: 75d5ae8b373c6ee00c3f263aea39dc02 (MD5) Previous issue date: 2018-10-19bitstream/item/184757/1/apsjournals.apsnet.org-Identification-of-Eight-Solanum-subgenus-Leptostemonum-Species-as-Novel-Natural-Hosts-of-Tomato-chlor.pd

    Avaliação da reação de acessos de Solanum subinerme e S. acanthodes ao nematoide-das-galhas Meloidogyne enterolobii para uso como porta-enxerto resiste.

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    O objetivo deste trabalho foi avaliar acessos silvestres da famĂ­lia solanaceae e sugĂȘnero Leptostemonum enterolobii para uso como porta-enxerto resistente.Resumo

    TerapĂȘutica de PrecisĂŁo e suas Perspectivas em um PaĂ­s de PecuĂĄria HeterogĂȘnea.

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    Quando se considera o foco em saĂșde animal, entende-se terapĂȘutica de precisĂŁo como a gestĂŁo do conjunto de tecnologias/prĂĄticas que podem ser customizadas em função de caracterĂ­sticas individuais para promover ganhos terapĂȘuticos com o uso mĂ­nimo e otimizado de medicamentos e produtos biolĂłgicos no tratamento e prevenção de enfermidades de animais

    Experimental and Theoretical Study on the One- and Two-Photon Absorption Properties of Novel Organic Molecules Based on Phenylacetylene and Azoaromatic Moieties

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    This Article reports a combined experimental and theoretical analysis on the one and two-photon absorption properties of a novel class of organic molecules with a pi-conjugated backbone based on phenylacetylene (JCM874, FD43, and FD48) and azoaromatic (YB3p2S) moieties. Linear optical properties show that the phenylacetylene-based compounds exhibit strong molar absorptivity in the UV and high fluorescence quantum yield with lifetimes of approximately 2.0 ns, while the azoaromatic-compound has a strong absorption in the visible region with very low fluorescence quantum yield. The two-photon absorption was investigated employing nonlinear optical techniques and quantum chemical calculations based on the response functions formalism within the density functional theory framework. The experimental data revealed well-defined 2PA spectra with reasonable cross-section values in the visible and IR. Along the nonlinear spectra we observed two 2PA allowed bands, as well as the resonance enhancement effect due to the presence of one intermediate one-photon allowed state. Quantum chemical calculations revealed that the 2PA allowed bands correspond to transitions to states that are also one-photon allowed, indicating the relaxation of the electric-dipole selection rules. Moreover, using the theoretical results, we were able to interpret the experimental trends of the 2PA spectra. Finally, using a few-energy-level diagram, within the sum-over-essential states approach, we observed strong qualitative and quantitative correlation between experimental and theoretical results.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Air Force Office of Scientific ResearchKOLUMB fellowship by the Foundation for Polish Science (FNP

    FMRFamide-Like Peptides (FLPs) Enhance Voltage-Gated Calcium Currents to Elicit Muscle Contraction in the Human Parasite Schistosoma mansoni

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    Schistosomes are amongst the most important and neglected pathogens in the world, and schistosomiasis control relies almost exclusively on a single drug. The neuromuscular system of schistosomes is fertile ground for therapeutic intervention, yet the details of physiological events involved in neuromuscular function remain largely unknown. Short amidated neuropeptides, FMRFamide-like peptides (FLPs), are distributed abundantly throughout the nervous system of every flatworm examined and they produce potent myoexcitation. Our goal here was to determine the mechanism by which FLPs elicit contractions of schistosome muscle fibers. Contraction studies showed that the FLP Tyr-Ile-Arg-Phe-amide (YIRFamide) contracts the muscle fibers through a mechanism that requires Ca2+ influx through sarcolemmal voltage operated Ca2+ channels (VOCCs), as the contractions are inhibited by classical VOCC blockers nicardipine, verapamil and methoxyverapamil. Whole-cell patch-clamp experiments revealed that inward currents through VOCCs are significantly and reversibly enhanced by the application of 1 ”M YIRFamide; the sustained inward currents were increased to 190% of controls and the peak currents were increased to 180%. In order to examine the biochemical link between the FLP receptor and the VOCCs, PKC inhibitors calphostin C, RO 31–8220 and chelerythrine were tested and all produced concentration dependent block of the contractions elicited by 1 ”M YIRFamide. Taken together, the data show that FLPs elicit contractions by enhancing Ca2+ influx through VOCC currents using a PKC-dependent pathway
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