Scielo RSS <![CDATA[Electronic Journal of Biotechnology]]> vol. 3 num. 2 lang. es <![CDATA[SciELO Logo]]> <![CDATA[<B>Prospects for using transgenic resistance to insects in crop improvement</B>]]> 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 derived genes can be realised by deploying them in combination with host plant resistance and exotic genes. Genes conferring resistance to insects have been inserted into crop plants such as maize, cotton, potato, tobacco, potatoes, rice, broccoli, lettuce, walnuts, apples, alfalfa and soybean. Genetically transformed crops with Bt genes have been deployed for cultivation in USA, China and Australia. However, very little has been done to use this technology for improving crop production in the harsh environments of the tropics, where the need for increasing food production is most urgent. International agricultural research centres, advanced research institutes and the seed sector should make an effort to use these new tools for increasing food production in poorer regions of the world. There is an urgent need to develop a scientifically sound strategy to deploy exotic and plant derived genes for minimising the extent of losses caused by insect pests. Equally important is the need for following the biosafety regulations, more responsible public debate, social attitude and better presentation of the benefits for a rational deployment of the genetically transformed plants. <A NAME="Article"></A> <![CDATA[<B>The commercialization of bioinformatics</B>]]> 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 pharmaceutical companies discovered a potential means to cure their innovation deficit. One of the early models for commercializing bioinformatics was simply to sell access to databases of human nucleotide sequencFes. This strategy is heading toward obsolescence as the public consortium nears its goal of sequencing the human genome. The key to future commercialization of sequence data will be to develop informatics technology that transforms this data into information that is useful for diagnosis and therapy. A competitive transformation of sequence data into information will require improvements in data integration and data mining. <A NAME="article"></A> <![CDATA[<B>Formation of highly porous biodegradable scaffolds for tissue engineering</B>]]> 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 and phase separation, are compared on the basis of porosity, pore size, and promotion of tissue growth. <A NAME="Article"></A> <![CDATA[<B>An international political economic view of the biotechnology industry</B>]]> 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 include both strategic and traditionally non strategic interests when reviewing policy formulation and objectives for firms in the biotechnology industry. <![CDATA[<B>Plant genomic instability detected by microsatellite-primers</B>]]> 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 the determination of genetic instability at early stages in in vitro culture. <A NAME="Article"></A> <![CDATA[<B>Semi-quantitative detection of genetically modified grains based on CaMV 35S promoter amplification </B>]]> 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 don’t give a good quantitative estimation of the detected signal. We developed a semi-quantitative method based on the comparison of the mass of the amplification product of the sample with the mass obtained from standard samples of known GMO concentration delivering an accurate estimation of the amount of GMO in a sample. At the same time the reaction is countersigned by an internal reaction control. A strict set up of the conditions is essential to control error-prone steps (like the quantification of the DNA template and of the DNA products and pipetting errors) that may bias the result. Using this protocol, we were able to routinely assess the quantity of transgenic grains present in shipments that sum more than 600,000 tons of corn and 250,000 tons of soybean exported between 1997 and 1999. <A NAME="Article"></A> <![CDATA[<B>Protocol for regeneration in vitro of <I>Arachis hypogaea</I> L</B>]]> 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 reproductive stage. <![CDATA[<B>Mitotic aberrations in coffee (<I>Coffea arabica</I> cv. 'Catimor') leaf explants and their derived embryogenic calli </B>]]> 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 abnormalities such as c-mitosis, chained chromosomes, multipolar metaphases and chromosome bridges. Therefore, we conclude that these pre-existing abnormalities originate by errors in the process of normal mitosis in both leaves and in calli, and are therefore not caused by tissue culture conditions. <A NAME="Article"></A>