6,588 research outputs found

    Four gene introduction methods affect the shoot regeneration and localization of transgene expression in greenhouse stem explants and in vitro-grown chrysanthemum stem thin cell layers

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    Gene introduction method (GIM) affected shoot regeneration capacity (SRC) in standard and spray-type chrysanthemums. SRC was both cultivar and GIM-dependent in both in vitro and greenhouse stem explants, the former significantly higher than the latter. Sonication had an SRC-stimulating effect on in vitro explants. Other GIMs (Agrobacterium, biolistics, Agrolistics) had an SRC-inhibiting effect on greenhouse explants. Genotype-dependence of SRC was observed in both in vitro and greenhouse material. SRC is influenced by the explant and regeneration media, which should be modified if altered by the GIM. Shoots derived from all GIM treatments showed normal growth under in vitro and greenhouse conditions, and flowered normally. In addition, this study further shows that explant origin (in vitro versus greenhouse) and cultivar significantly affect the regeneration process, even when an optimized medium is utilized. The integration of the GUS transgene is also GIM-dependent, but in all cases is shown to occur in the venation. (African Journal of Biotechnology: 2003 2(5): 114-123

    Flutuação de infestação da broca-do-café (Hypothenemus Hampei, Ferrari) em Rondônia, 2002.

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    Introdução; Material e métodos; Resultados e discussão; Conclusões; Referências bibliográficas.bitstream/item/70954/1/BPD11-brocadocafe.pd

    Development and characterization of an environmentallyfriendly process sequence (autohydrolysis and organosolv) for wheat straw delignification

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    The present work describes the delignification of wheat straw through an environmentally friendly process resulting from sequential application of autohydrolysis and organosolv processes. Wheat straw autohydrolysis was performed at 180°C during 30 min with a liquid–solid ratio of 10 (v/w); under these conditions, a solubilization of 44% of the original xylan, with 78% of sugars as xylooligosaccharides of the sum of sugars solubilized in the autohydrolysis liquors generated by the hemicellulose fraction hydrolysis. The corresponding solid fraction enrichment with 63.7% of glucan and 7.55% of residual xylan was treated with a 40% ethanol and 0.1% NaOH aqueous solution at a liquid–solid ratio of 10 (v/w), with the best results obtained at 180°C during 20 min. The highest lignin recovery, measured by acid precipitation of the extracted lignin, was 3.25 g/100 ml. The lignin obtained by precipitation was characterized by FTIR, and the crystallinity indexes from the native cellulose, the cellulose recovered after autohydrolysis, and the cellulose obtained after applying the organosolv process were obtained by X-ray diffraction, returning values of 21.32%, 55.17%, and 53.59%, respectively. Visualization of the fibers was done for all the processing steps using scanning electron microscopy.The authors thank Professor Juan Carlos Parajo from University of Vigo, for the assistance in the materials preparation under autohydrolysis process as well as the ALBAN program for the PhD fellowship support

    Continuous beer fermentation with yeast immobilized on alternative cheap carriers and sensorial evaluation of the final product

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    Continuous beer fermentation offers a wide range of advantages, mostly of economic nature over the traditional batch process. However, due to increased complexity of operation comparing to batch process, flavor problems, risk of contamination, yeast viability, carrier price and inconvenience of immobilization, the continuous beer fermentation has found few practical applications so far. The carrier cost represents a significant part of the investment costs and therefore the need for a cheap support material easy to regenerate is still relevant. This work deals with a complete continuous fermentation system for beer fermentation and maturation consisting of an airlift and a packed-bed reactor containing brewing yeast immobilized on spent grains and corncobs, respectively. The objective of this study was to verify the long-term performance of the system and the suitability of these new cellulose-based carrier materials made from brewing and agricultural by-products. Further the influence of feed rate and aeration rate on bioreactors fermentation performance, immobilized biomass load, ethanol production and flavor profile of both green and maturated beer was followed. The influence of process parameters on sensorial quality of beer has been studied by physicochemical methods as well as by sensorial analysis (acceptance and description tests) carried out by both consumers and experienced tasters. This work clearly demonstrated the technological feasibility of the continuous brewing based on yeast immobilization on cheap alternative carriers (spent grains, corncobs) for continuous production of a beer with a balanced flavor profile.Fundação para a Ciência e a Tecnologia (FCT) - SFRH / BPD / 3541 / 2000.Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) - Proc. 00/12767-4.Unicer SA.

    Most Preprint Servers Allow the Publication of Opinion Papers

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    Preprints are not only a raw form of research presentation, but also increasingly used as a gateway of entry into peer-reviewed journals. Several preprint servers are in existence, and some serve specific thematic groups or specialties, while others have a broader thematic scope. In this letter, we examined 36 preprint servers in March of 2023, noting that the majority (27/36 or 75%) accept opinion papers, two have an unclear, unstated, or unknown set of policies, while seven, including some of the most popular (biorXiv, medRxiv, Research Square), do not explicitly accommodate opinion papers. We opine that it would be in the interests of those preprint servers that do not publish opinion papers or evidence-based opinion papers to modify their scope of manuscript types in order to expand their user base and attract more participating scientists, but also to provide a more holistic set of scientific publishing objectives that accommodates a wider and more inclusive range of views

    Isolamento e caracterização de bactérias presentes em explantes cultivados in vitro do clone FDR5865 de seringueira.

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    A seringueira é a fonte natural da borracha e sua cultura é explorada mundialmente. É uma planta alógama, suas sementes são recalcitrantes e a propagação vegetativa é o método mais recomendado. Com o preço elevado do petróleo, a borracha sintética, apesar de ser mais barata que a natural, fica menos competitiva, além disso, tem-se a pressão pelo uso de produtos naturais. O presente trabalho teve como objetivo caracterizar isolados bacterianos oriundos de explantes de seringueira cultivados in vitro e testar a sua sensibilidade à antibióticos. Após desinfestação segmentos nodais do clone FDR5865 foram inoculados em meio de cultura WPM e mantidos em sala de crescimento. Após 30 dias, o material que apresentou contaminação bacteriana visível foi selecionado e os contaminantes foram purificados utilizando o método de esgotamento por estrias. Posteriormente, os isolados foram testados quanto a sua sensibilidade à antibióticos e caracterizados morfologicamente. Foram encontrados dois tipos de bactérias, que foram nomeadas de isolados 1 e 2, estas foram caracterizadas como Gram negativas e apresentaram forma de cocos. O isolado 1 foi a mais resistente, apresentando resistência a 19 dos 20 antibióticos testados. Este trabalho tem caráter pioneiro, visto que a utilização de explantes de plantas oriundas do campo é pouco relatada na literatura e apresenta um grau de dificuldade muito maior do que a utilização de material provindo de casa de vegetação

    High gravity batch and continuous processes for beer production: evaluation of fermentation performance and beer quality

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    This study deals with two innovative brewing processes, high gravity batch and complete continuous beer fermentation systems. The results show a significant influence of the variables such as concentration and temperature on the yield factor of the substrate into ethanol and consequently on the productivity of the high gravity batch process. The technological feasibility of continuous production of beer based on yeast immobilization on cheap alternative carriers was also demonstrated. The influence of process parameters on fermentation performance and quality of the obtained beers was studied by sensorial analysis. No significant difference in the degree of acceptance between the obtained products and some traditional market brands was found.FAPESP; CAPES; CNPq (Brazil); Malteria do Vale, Wallerstein Industrial e Commercial, Corn Products Brasil; Johnson-Diversey; FCT/Portugal; MŠMT Czech Republic; Unicer S.A

    Aqueous two-phase micellar systems in an oscillatory flow micro-reactor: Study of perspectives and experimental performance

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    Aqueous two-phase micellar systems (ATPMS) are micellar surfactant solutions with physical properties that make them very efficient for the extraction/concentration of biological products. In this work the main proposal that has been discussed is the possible applicability and importance of a novel oscillatory flow micro-reactor (micro-OFR) envisaged for parallel screening and/or development of industrial bioprocesses in ATPMS. Based on the technology of oscillatory flow mixing (OFM), this batch or continuous micro-reactor has been presented as a new small-scale alternative for biological or physical-chemical applications. RESULTS: ATPMS experiments were carried out in different OFM conditions (times, temperatures, oscillation frequencies and amplitudes) for the extraction of glucose-6-phosphate dehydrogenase (G6PD) in Triton X-114/buffer with Cibacron Blue as affinity ligand. CONCLUSION: The results suggest the potential use of OFR, considering this process a promising and new alternative for the purification or pre-concentration of bioproducts. Despite the applied homogenization and extraction conditions have presented no improvements in the partitioning selectivity of the target enzyme, when at rest temperature they have influenced the partitioning behavior in Triton X-114 ATPMS.The authors acknowledge the financial support from FCT (Fundacao para a Ciencia e Tecnologia/Portugal, SFRH/BPD/26108/2005), as well as from FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo/Brasil), CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico/Brasil), and CAPES (Coordenacao para Aperfeicoamento do Ensino Superior/Brasil)
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