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| Registros recuperados: 12.472 | |
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| Banerjee,Meenakshi; Mishra,Shanoo; Chatterjee,Jhuma. |
| The ubiquity of heavy metals in the biosphere results in the introduction of high amounts of toxic metals into the food chain from various sources. In the present study, one of the strongest nitrogen fixing cyanobacterium of the rice fields, Aulosira fertilissima, was subjected to nickel and chromium stress and the ameliorating effect of immobilization was investigated. Cell immobilization could protect the organism’s growth against the toxicity of both heavy metals at LC50 as compared to lethal concentrations. The nitrate reductase activity in free cells treated with the metals was substantially inhibited but immobilized cells treated with 0.1 ppm nickel was not affected by the metal treatment. Cell immobilization also resulted in a significant... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000300013 |
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| Kalalou,Ichraq; Faid,Mohamed; Touhami Ahami,Ahmed. |
| Studies were conducted to stabilize minced meat by fermentation using mixed lactic acid bacteria cultures isolated from natural fermented foodstuffs and selected for their antimicrobial activity against some hazardous microorganisms. Fresh meat of camel purchased from the slaughterhouse of Rabat (Morocco) was minced separately with a meat mincer and supplied with 5% glucose, then inoculated with lactic acid bacteria. Microbiological analyses were carried out to determine standard plate count (SPC), staphylococci, coliforms, enterococci, and lactic acid bacteria. All analyses were determined after 1, 2, 3, 4 and 7 days during the storage. Results showed that a low pH of 4.0-4.2 can be achieved (within 3 days at 22ºC), with a drastic reduction in... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000300005 |
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| Saraswathy,Nachimuthu; Kumar,Polumetla Ananda. |
| Bacillus thuringiensis (Bt) is a valuable environment-friendly biopesticide, which occupies 90% of the world biopesticide market. Its insecticidal properties are attributed to the presence of <FONT FACE=Symbol>d-</FONT>endotoxins which are synthesized during the sporulation phase of the bacterium. <FONT FACE=Symbol>d-</FONT>endotoxin or crystal toxin is a multi-domain protein molecule comprising of three distinct domains. Domain I is made of seven alpha-helices, domain II comprises three antiparallel beta sheets, which are folded into loops and domain III is made of a beta sandwich of two antiparallel beta strands. Molecular studies on the structure and functional properties of different <FONT... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000200009 |
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| Hussein,Hany; Ibrahim,Soha Farag; Kandeel,Kamal; Moawad,Hassan. |
| Biosorption experiments for Cr(VI), Cu(II), Cd(II) and Ni(II) were investigated in this study using nonliving biomass of different Pseudomonas species. The applicability of the Langmuir and Freundlich models for the different biosorbent was tested. The coefficient of determination (R²) of both models were mostly greater than 0.9. In case of Ni(II) and Cu(II), their coefficients were found to be close to one. This indicates that both models adequately describe the experimental data of the biosorption of these metals. The maximum adsorption capacity was found to be the highest for Ni followed by Cd(II), Cu(II) and Cr(VI). Whereas the Freundlich constant k in case of Cd(II) was found to be greater than the other metals. Maximum Cr(VI) removal reached around... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000100006 |
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| Sasseville,Maxime; St-Louis,Catherine; Khoudi,Habib; Beauregard,Marc. |
| Protein design is currently used for the creation of new proteins with desirable traits, which include a superior nutritional value. One of the challenges of protein design in this area is to achieve the production of stable native-like proteins that resist the proteolytic pressure of the organism used for its production (the bioreactor). We report here the identification of a specific peptide bond sensitive to E. coli proteolysis in the designer protein MB-1Trp. In an attempt to reduce proteolysis, we have created a MB-1TrpHis gene library in which the two amino acids surrounding the peptide bond, N44 and L45, were randomized using degenerated oligonucleotides. The initial characterization of MB-1TrpHis N44E/L45V and MB-1TrpHis N44E/L45M, 2 variants of... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000300004 |
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| Rajoka,Muhammad Ibrahim. |
| The influence of carbon and nitrogen sources on the production of exo-glucanase was investigated. The enzyme production was variable according to the carbon or nitrogen source used. Levels of beta-cellobiohydrolase (CBH) were minimal in the presence of even low concentrations of glucose. Enzyme production was stimulated by other carbohydrates and thus is subject to carbon source control by easily metabolizable sugars. In Dubos medium, on cellobiose, the cellobiohydrolase titres were 2-to 110-fold higher with cells growing on monomeric sugars and 2.7 times higher than cells growing on other disaccharides. alpha-Cellulose was the most effective inducer of beta-cellobiohydrlase and filter paperase (FPase) activities, followed by kallar grass straw.... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000300007 |
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| Tiznado-Hernández,Martín-Ernesto; Gaffe,Joel; Handa,Avtar K. |
| Pectin methylesterase (PME) is an enzyme located in the plant cell wall of higher plants whose physiological role is largely unknown. We had isolated a PME gene from a tomato genomic library, including 2.59 kb of 5´ flanking region and the coding region. Both coding and promoter region were sequenced and computer analyzed. Tobacco transgenic plants were created harboring constructs in which 2.596 Kb, 1.306 Kb and 0.267 Kb sizes of the promoter were driving the expression of β-Glucuronidase gene (GUS). GUS activity was studied by histochemical and fluorometric assays. Two introns of 106 and 1039 bp were found in the coding region and phylogenetic analysis placed this PME gene closer to genes from Citrus sinensis and Arabidopsis thaliana than tomato... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000100004 |
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| Mendonça,Elsa; Martins,Aida; Anselmo,Ana Maria. |
| The mycelium of Fusarium flocciferum was assayed for its ability to degrade aromatic compounds, namely, gallic, protocatechuic, vanillic, syringic, caffeic, and ferulic acids and syringic aldehyde, commonly found in agro-industrial wastes. The biodegradation assays were performed in liquid medium with the phenolic compounds as single substrates and as a synthetic mixture containing the seven aromatic compounds. The results with single substrates indicated that in 24 hrs of incubation the fungus was able to reduce the phenolic concentration from 200 mg/l to below detection limits, except for syringic acid, being the lowest degradation rates found for this acid and its aldehyde. The biodegradation experiments with the mixture of phenolic compounds showed... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000100005 |
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| Bustamante,José O. |
| Coconut is a major crop of many poor nations. The present paper shows with inexpensive fluorescence microscopy of the enhanced green fluorescent protein (EGFP), that coconut water has the capability of synthesizing proteins from recombinant DNA vectors. After only 4 hrs of 100 pM application of the EGFP plasmid (pEGFP), a strong fluorescent signal was detected with an off-the-shelf, low-tech CCD webcam. Since natural coconut water is sterile, this heat-stable delivery system may be a good option for the dissemination of food supplements and pharmaceuticals in poor nations. As expensive substances could be expressed in coconut water, through bioreactor technology or micropropagation, the concepts presented here may prove invaluable to the economic and... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000100002 |
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| Narayanan,Niju; Roychoudhury,Pradip K.; Srivastava,Aradhana. |
| Lactic acid has been first introduced to us as early as 1780 as a sour component of milk. Ever since we have found its applications in food, pharmaceutical, cosmetic industries etc. Now there are emerging uses as a potential feedstock for the biodegradable polymer industry. The microorganisms being used for lactic acid fermentation, the raw materials reported, the various novel fermentation processes and its processing methods have been reviewed. The properties and applications of lactic acid, its derivatives and polymer have been discussed. The various routes to polymerization and the companies presently involved in lactic acid production have been covered |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000200008 |
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| Puchooa,Daneshwar. |
| Agriculture today faces the challenge of sustainable productivity and improved food security on a shrinking area of land under cultivation. Until recently, biotechnology has been viewed as an expensive technology affordable only by rich industrial countries. However, it is now increasingly considered as an essential tool for developing countries to tackle the numerous problems of underdevelopment. Unfortunately, to date, Mauritius, like many other countries in Africa, lags far behind in development, use and commercialisation of biotechnology. This paper outlines the current status of biotechnology in Mauritius, some important constraints faced, as well as how policy makers are planning to make Mauritius “assume the role of a service provider and... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000200004 |
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| Balarim,Carlos R.; Targa,Luiz A.; Virgens Filho,Jorim S.; Andrade Filho,Alceu G.; Wiecheteck,Giovana K.. |
| A implantação de microcentrais hidrelétricas é uma das alternativas para suprir com energia comunidades pequenas e isoladas, situadas normalmente na área rural. O aproveitamento de potenciais hidráulicos de pequeno porte é uma alternativa cada vez mais viável devido não só à falta de recursos financeiros para os grandes empreendimentos, mas também pelo imenso potencial de geração em centrais de pequeno porte, que pouco tem sido aproveitado. O objetivo deste trabalho foi de apresentar uma metodologia simples de engenharia para estimar o custo das Bombas Funcionando como Turbinas (BFTs) utilizadas em microcentrais hidrelétricas, que possam ser usadas em estudos preliminares de novos aproveitamentos hidrelétricos, sem uma investigação detalhada dos lugares... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Microcentral; Energia elétrica; Bombas hidráulicas. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162004000100025 |
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| Carvalho,Joaquim J. de; Azevedo,Carlos A.V. de; Henrique,Jacqueline; Dantas Neto,José; Lima,Vera L. Antunes de; Pordeus,Roberto V.. |
| Esta pesquisa teve como objetivo verificar as variabilidades espaciais e temporais no tempo de avanço e no tempo de oportunidade de infiltração d'água e seus reflexos no tempo de aplicação d'água num sistema de irrigação por sulcos com fluxo reduzido para um solo franco-arenoso. As avaliações de campo foram realizadas no perímetro irrigado de São Gonçalo, Sousa - PB, onde foram feitas medições em seis sulcos, eqüidistantes, de forma a abranger o máximo possível a variabilidade em toda a área, nos 12 eventos de irrigação da estação de cultivo. Observando os tempos de avanço e de oportunidade de infiltração d`água no final da área irrigada em cada evento e em cada sulco ao longo do tempo, verificou-se que a variação espacial no tempo de avanço foi mais... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Tempo de avanço; Tempo de aplicação d'água; Irrigação por sulcos. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162004000200026 |
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| Sarria,Saul D.; Honório,Sylvio L.. |
| O resfriamento e/ou congelamento de produtos hortícolas, depois da colheita, é realizado com o objetivo de retirar o calor desses produtos, permitindo-lhes, em função disso, um tempo maior de conservação. Portanto, o conhecimento das propriedades físicas que envolvem transferência de calor do figo "Roxo de Valinhos" é útil para o cálculo de projetos e a análise de sistemas de engenharia de alimentos em geral, assim como para o emprego em equações de modelos matemáticos termodinâmicos. Neste trabalho, foram determinadas, experimentalmente, a condutividade e a difusividade térmica do figo inteiro no estádio rami e, a partir desses valores, foi determinado o calor específico. Foi utilizado o método transiente da Fonte Linear de Calor. Foi introduzida nas... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Figo inteiro; Transferência de calor; Calor específico. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162004000100021 |
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| Registros recuperados: 12.472 | |
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