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| Registros recuperados: 8.210 | |
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| Peterson, Garry D; McGill University; garry.peterson@mcgill.ca; Cunningham, Saul; CSIRO Entomology; saul.cunningham@ento.csiro.au; Deutsch, Lisa; Department of Systems Ecology, Stockholm University; lisad@system.ecology.su.se; Erickson, Jon; Rensselaer Polytechnic Institute; erickj@rpi.edu; Quinlan, Allyson; Conservation Ecology; aquinlan@resalliance.org; Tinch, Robert; School of Environmental Sciences, University of East Anglia; R.Tinch@uea.ac.uk; Troell, Max; Beijer Institute, Royal Swedish Academy of Sciences; max@system.ecology.su.se; Woodbury, Peter; Boyce Thompson Institute for Plant Research; pbw1@cornell.edu; Zens, Scot; Department of Biology, Dartmouth College; zens@dartmouth.edu. |
| The benefits and risks of any particular GM crop depend on the interactions of its ecological functions and natural history with the agroecosystem and ecosystems within which it is embedded. These evolutionary and ecological factors must be considered when assessing GM crops. We argue that the assessment of GM crops should be broadened to include alternative agricultural practices, ecosystem management, and agricultural policy. Such an assessment would be facilitated by a clearer understanding of the indirect costs of agriculture and the ecological services that support it. The benefits of GM crops should be compared to those of other means of agricultural intensification such as organic farming, integrated pest management, and agricultural policy reform.... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Agriculture; Biotechnology; Genetically modified crops (GM); Interdisciplinary; Public dialogue; Regulation; Risk assessment. |
| Ano: 2000 |
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| Dawe, Neil K; Canadian Wildlife Service; Neil.Dawe@ec.gc.ca; Bradfield, Gary E; University of British Columbia; garyb@interchange.ubc.ca; Boyd, W. Sean; Canadian Wildlife Service; Sean.Boyd@ec.gc.ca; Trethewey, Donald E. C.; Canadian Wildlife Service;; Zolbrod, A. Nana; University of British Columbia; nzolbrod@hotmail.com. |
| Vegetation changes were monitored over a 13-yr period (1982-1994) in the Campbell River estuary following the development of marshes on four intertidal islands. The marshes were created to mitigate the loss of a natural estuarine marsh resulting from the construction of a dry land log-sorting facility. Plant species coverage was measured along 23 permanent transects in planted and unplanted blocks on the constructed islands, and in naturally occurring low-marsh and mid-to-high marsh reference communities on nearby Nunn’s Island. Five dominant species, Carex lyngbyei, Juncus balticus, Potentilla pacifica, Deschampsia caespitosa, and Eleocharis palustris established successfully and increased in cover in both planted and unplanted areas. The... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Adaptive management of ecosystems; Carex lyngbyei; Deschampsia caespitosa; Eleocharis palustris; Estuarine marsh creation; Juncus balticus; Long-term vegetation dynamics; Mitigation cautions; Natural vs. constructed wetlands; Potentilla pacifica; Restoration ecology; Wetland creation. |
| Ano: 2000 |
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| Bhandarkar,Satej V.; Neau,Steven H.. |
| The influences of water activity and solvent hydrophobicity on the kinetics of the lipase-catalyzed enantioselective esterification of flurbiprofen with n-butanol were investigated. The solvent effect was not similar for lipases from Candida rugosa (Crl), Mucor javanicus (Mjl), and porcine pancreas (Ppl). The lipase-catalyzed reaction rates in different solvents across a wide range of water activities revealed that the Ppl-catalyzed reaction exhibited no enantioselectivity and no substantial water activity or solvent dependence. The Mjl-catalyzed reaction proceeded faster, preferring the R-enantiomer reaction over that of its antipode, but had little solvent or water activity dependence. The Crl-catalyzed reactions in n-heptane and n-nonane had similar... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000300003 |
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| Mikos,Antonios G.; Temenoff,Johnna S.. |
| In recent years, lack of donor organs has caused many to consider tissue engineering methods as means to replace diseased or damaged organs. This newly-emerging field uses tissue-specific cells in a three-dimensional organization, provided by a scaffolding material, to return functionality of the organ. For these applications, the choice of scaffolding material is crucial to the success of the technique. In addition to the chemical properties of the material, physical properties such as surface area for cell attachment are essential. Various methods of creating pores in these materials to increase surface area are reviewed here. Scaffolds formed using the different techniques, which include fiber bonding, solvent casting/particulate leaching, gas foaming... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000200003 |
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| Park,No-Hee; Kang,Mo K.. |
| Development of oral cancer proceeds through discrete molecular genetic changes that are acquired from the loss of genomic integrity after continued exposure to environmental risk factors. Of particular importance in oral cancer development are tobacco-related chemical carcinogens and human papillomavirus (HPV) infection. To understand the mechanisms by which these risk factors contribute to tumorigenesis, we developed an in vitro model of sequential, multistep oral carcinogenesis model of normal human oral keratinocytes (NHOK) by immortalizing these cells with cloned "high risk" HPV genome. HPV viral genome alone failed to give rise to a tumorigenic cell population, which required further exposure to chemical carcinogens. HPV-immortalized cells exhibited... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000100005 |
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| de la Riva,Gustavo A.. |
| Agriculture is expected to feed an increasing population, forecasted to reach 8 billion by 2020, out of whom 6.7 billion will be in developing countries where the carrying capacity of agricultural lands will soon be reached. In Latin American and the Caribbean (LAC) countries, in spite of the abundance of natural resources and continued investments in development, poverty and food insecurity affect more than 55 percent of the rural population. Fifteen years ago, plant biotechnology comprised only a few applications of tissue culture, recombinant DNA technology and monoclonal antibodies. Today, genetic transformation, and marker-aided selection and breeding are just a few of the examples of the applications in crop improvement with profound implications for... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000100001 |
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| Pownall,Ian Edward. |
| This paper uses a model developed from the international political economy (IPE) school, to address the structure of the biotechnology industry. In particular, by focusing upon four primary structural elements of the industry, knowledge, production, finance and security with key secondary considerations of biosafety, public opinion and choice of intellectual property regime, the development of biotechnology companies from developed countries fits within a triad dominated industry with specific interests towards firms from developing countries. The activities of a sample of US National Association of Securities Dealers Stock Market (NASDAQ) quoted biotechnology firms are investigated to support the model which concludes by the observation of the need to... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000200004 |
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| Guacucano,Maritza; Levican,Gloria; S. Holmes,David; Jedlicki,Eugenia. |
| During the course of experiments involving RT-PCR to investigate the co-transcription of the pet and res operons of the bacterium Acidithiobacillus ferrooxidans we observed that the mRNA of certain gene pairs can be amplified by RT-PCR in the absence of added RT-primer. We provide experimental evidence that eliminates, as explanations for the observed results, the possible global contamination of the RNA preparation by genomic DNA or by contaminating single stranded DNA or RNA fragments. We suggest that the results can be explained by self-priming of the RNA perhaps as a result of secondary structure configurations that provide a suitable 3-terminus to prime the reverse transcriptase. This type of artifact can be recognized by carrying out a control in... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000300005 |
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| Jones,Phillip B.C.. |
| Biological research has experienced a paradigm shift from in vivo or in vitro experimentation to in silico experimentation, a development that relies upon bioinformatics. The beginning of bioinformatics stems from the fortuitous timing of the adoption of new DNA sequencing methods and the availability of mini-and bench-top computers, which became the tools to store and to analyze the sequence data. Another fortunate coincidence was the popularization of the Internet, which provided a means to exchange sequence data and sequence analysis software, and the establishment of the Human Genome Project, which stimulated the need for sophisticated data management and analysis tools. Market pull has rapidly stimulated bioinformatics commercialization as... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000200002 |
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| Tozzini,Alejandro C.; Martínez,M. Carolina; Lucca,M. Florencia; Vázquez Rovere,Cecilia; Distéfano,Ana Julia; del Vas,Mariana; Hopp,Esteban. |
| The detection and exact quantification of the presence of GMOs (genetically modified organisms, also named as living modified organisms, LMOs) grains has become very important in international commercial transactions, especially from countries producing both types of commodities, GMOs and GMO-free. This makes necessary to check every batch previous delivery to the recipient country. Several PCR protocols have been proposed to detect the presence of GMO DNA in a sample due to its sensitivity and independence of environmental and physiological influences. However, most of them are qualitative assays and dont give a good quantitative estimation of the detected signal. We developed a semi-quantitative method based on the comparison of the mass of the... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000200006 |
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| Flint,Jason; Irarrazabal,Carlos; Dellacha,Juan. |
| CamBioTec, a Canadian-Latin American Network promoting the safe and effective use of agricultural and environmental biotechnology, undertook an analysis of the current capacities of Argentina, Chile and Canada with respect to the management of information related to assessment and approval of products of modern biotechnology/ genetically engineering. This report is based on data obtained during a number of interviews and institutional visits conducted during August 1998 and includes: an overview of current regulatory policy, identification of key human resources and authorities, analysis of information management capacity, recommendations for capacity building, and descriptions of relevant international initiatives. Canada has a regulatory system in place... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000100002 |
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| Leroy,Xavier J.; Leon,Karine; Branchard,Michel. |
| This report describes a new application of the Inter-Simple Sequence Repeat (ISSR) technique. This technology based on the amplification of regions between microsatellites was applied to different calli from the same cauliflower mother plant. One of the tested ISSR primers, (GATA)4, generated great polymorphism. Twelve different markers were detected on polyacrylamide gels. After sequencing, one sequence showed homology with a predicated A. thaliana gene closely related to genes involved in the regulation of cell proliferation in mammalians. This marker is characterised by three microsatellites and a palindromic sequence. Possible causes of mutations in this marker are discussed and will be investigated. ISSR amplification appears as a reliable method in... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000200005 |
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| Sharma,Hari C.; Sharma,Kiran K.; Seetharama,Nadoor; Ortiz,Rodomiro. |
| Integrated pest management has historically placed great hopes on host plant resistance. However, conventional host-plant resistance to insects involves quantitative traits at several loci. As a result, the progress has been slow and difficult to achieve. With the advent of genetic transformation techniques, it has become possible to clone and insert genes into the crop plants to confer resistance to insect pests. Resistance to insects has been demonstrated in transgenic plants expressing genes for delta-endotoxins from Bacillus thuringiensis (Bt), protease inhibitors, enzymes and plant lectins. Most of the plant derived genes produce chronic rather than toxic effects and some insect pests are not sensitive to some of these factors. The potential of plant... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000200001 |
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| Azevedo,João Lúcio; Maccheroni Jr.,Walter; Pereira,José Odair; de Araújo,Welington Luiz. |
| In the past two decades, a great deal of information on the role of endophytic microorganisms in nature has been collected. The capability of colonizing internal host tissues has made endophytes valuable for agriculture as a tool to improve crop performance. In this review, we addressed the major topics concerning the control of insects-pests by endophytic microorganisms. Several examples of insect control are described, notably those involving the interactions between fungi and grazing grasses from temperate countries. The mechanisms by which endophytic fungi control insect attacks are listed and include toxin production as well as the influence of these compounds on plant and livestock and how their production may be affected by genetic and environmental... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000100004 |
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| Cucco,María Florencia; Rossi Jaume,Alberto Daniel. |
| The regeneration of peanut Runner varieties grown in the South of the province of Cordoba, Argentina, was studied to count on a regeneration protocol, which is essential to perform genetic transformation of the plant. The induction of somatic embryos was evaluated in different peanut explants cultivated in Cordoba: cotyledons with and without embryos, epycotils and leaflets, of the Tegua, Nahuel and Florman INTA varieties. The induction medium consisted of MS salts with 30 g.l-1 sucrose, supplemented with the following hormones and herbicides: BAP, Picloram, DMA and 2,4-D. The highest percentage of embryogenic callus was produced cultivating epicotyls with 50 mg.l-1 2,4-D. The embryos obtained produced plantlets which, once acclimatized, reached the... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000200007 |
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| Acevedo,Fernando. |
| Microbial processes applied to mining operations are gaining increasing interest in the last years. Potential and current applications include the mining of gold, copper and other heavy metals, desulfurization of coal and oil, tertiary recovery of oil and biosorption of metal ions. Currently, bacterial leaching of copper and biooxidation of refractory gold concentrates are well-established large-scale processes that are carried on using heaps and tank reactors. Heap operation is simple and adequate to handle large volumes of minerals, but their productivity and yields are limited because of the severe difficulties in exerting an adequate process control. On the other hand, reactors can economically handle moderate volumes of material, but they allow for a... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000300002 |
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| Bernstein,Carol; Bernstein,Harris; Payne,Claire; Garewal,Harinder. |
| A field of defective tissue (field defect) appears to be an early stage in the progression to adenocarcinoma of both the colon and the esophagus. In both cases the field is comprised of cells characterized by resistance to induction of apoptosis, aberrant increased proliferation and genomic instability. Specific mutations and epimutations occur in both types of field. Also there is evidence for aberrant overexpression or underexpression of specific proteins. Most of these early molecular alterations appear to promote either enhanced apoptosis resistance, proliferation, or genomic instability. The molecular alterations that are present early are often, but not always, also present to an even greater degree in the cancer itself. Many of the important events... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000300001 |
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| Menéndez-Yuffá,Andrea; Fernandez Da Silva,Rafael; Rios,Liliana; Xena de Enrech,Nereida. |
| Dividing cells of leaves used as sources of explants from coffee plants (Coffea arabica cv. 'Catimor') and those of their derived calli were analyzed for mitotic aberrations. The studied tissues were prepared by squashing and stained with carbolfuchsin. A total of 1551 leaf and 4568 callus cells were surveyed. The majority (79 %) of leaf and calli (75 %) cells showed normal mitosis, however, cells with mitotic abnormalities were also found in both tissues. These included: polyploids, aneuploids, sticky chromosomes, double prophases and lagging chromosomes. Additionally, interphase cells with micronuclei or binucleated were also observed. The frequencies of these abnormalities were statistically different in calli and leaves. Calli showed a few other... |
| Tipo: Journal article |
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| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582000000200008 |
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| Registros recuperados: 8.210 | |
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