Scielo RSS <![CDATA[Electronic Journal of Biotechnology]]> http://www.scielo.cl/rss.php?pid=0717-345820020001&lang=es vol. 5 num. 1 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[<B>A Manuscript Writing Course for Biochemistry Undergraduates and Graduate Students in the Biomedical Sciences</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100001&lng=es&nrm=iso&tlng=es <![CDATA[Biotechnology Issues for Developing Economies]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100002&lng=es&nrm=iso&tlng=es <![CDATA[<B>Microbial Diversity and Ecosystem Functions - the Unmined Riches</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100003&lng=es&nrm=iso&tlng=es <![CDATA[<B>Development of Biotechnology in South Africa</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100004&lng=es&nrm=iso&tlng=es Biotechnology in South Africa stands at a cross-roads. As a country with huge natural resources, equally huge social problems, and in a state of positive transition to full multi-cultural development, SA faces the complex task of effectively exploiting its science, technology and resource base for the benefit of its society. The potential of Biotechnology for social and economic development has only recently been a focal point. There are signs, at all levels from central administration to individual tertiary institutions, that the first decade of the 21st century may be the point where Biotechnology ‘comes of age’ in South Africa. <![CDATA[<B>The True Meaning of Technology Transfer</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100005&lng=es&nrm=iso&tlng=es Biotechnology in South Africa stands at a cross-roads. As a country with huge natural resources, equally huge social problems, and in a state of positive transition to full multi-cultural development, SA faces the complex task of effectively exploiting its science, technology and resource base for the benefit of its society. The potential of Biotechnology for social and economic development has only recently been a focal point. There are signs, at all levels from central administration to individual tertiary institutions, that the first decade of the 21st century may be the point where Biotechnology ‘comes of age’ in South Africa. <![CDATA[<B>Gene Discovery, Ownership and Access for Developing Countries in the Era of Molecular Genetics</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100006&lng=es&nrm=iso&tlng=es Biotechnology in South Africa stands at a cross-roads. As a country with huge natural resources, equally huge social problems, and in a state of positive transition to full multi-cultural development, SA faces the complex task of effectively exploiting its science, technology and resource base for the benefit of its society. The potential of Biotechnology for social and economic development has only recently been a focal point. There are signs, at all levels from central administration to individual tertiary institutions, that the first decade of the 21st century may be the point where Biotechnology ‘comes of age’ in South Africa. <![CDATA[<B>Genomic variability in <I>Vitis vinifera</I> L. "Sangiovese" assessed by microsatellite and non-radioactive AFLP test</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100007&lng=es&nrm=iso&tlng=es Microsatellite polymorphism analysis on 25 different "Sangiovese" accessions was carried out at eight microsatellite loci (VVS2, VVS4, VVS29, VVMD3, VVMD6, VVMD7, VVMD17 and VVMD21). In order to evaluate variability within the "Sangiovese" variety and to confirm variety identification, genotype analysis, allele distribution and pedigree information were processed with a DNA-automated sequencer running AlleleLinks software. DNA typing revealed three cases of genetic dissimilarity compared to registered "Sangiovese" clones and the divergent accessions thought to be different clones of the same variety. The divergent accessions were different from "Sangiovese" at four microsatellite loci (VVS2, VVS4, VVMD7 and VVMD21). An innovative non-radioactive modification of AFLP genome profiling confirmed the data obtained by microsatellite amplification test. These results underline the importance of biotechnological testing, such as the PCR-based DNA tests together with traditional ampelography, in Vitis vinifera L. clone and variety selection programmes to avoid misnaming and erroneous identification and to evaluate genetic relatedness and variability within populations <![CDATA[<B>Isolation and partial purification of a metabolite from a mutant strain of <I> Bacillus sp</I>. with antibiotic activity against plant pathogenic agents</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100008&lng=es&nrm=iso&tlng=es The use of microorganisms for biological purposes has become an effective alternative to control plant pathogens. There are many examples of formulations using bacterial or fungal strains with biocontrol applications. Among them, members of the genus Bacillus are well known antibiotic producers. However, the increased capacity of antibiotic production obtained by direct mutagenesis of wild strains, has seldom been reported in the open literature. This research refers to the mutation of the A47 Bacillus strain, a plant pathogen antagonist, in order to obtain an improved strain with enhanced capacity to synthesize metabolites with antibiotic activity. The mutant strain M40 was obtained using the mutagenic agent acridine orange. The mutant strain showed a higher antagonistic activity than the wild type A47 against the plant pathogen Botritys cinerea (grey mould), Ralstonia solanacearum (bacterial wilt) and Erwinia carotovora var. carotovora (bacterial soft rot). The final objective was to isolate the antibiotic metabolite produced by the M40 strain and to determine its chemical and antibiotic properties. The results revealed the presence of an extracellular, thermostable and methanol-soluble metabolite that absorbed light at 212nm. These characteristics are similar to those described for cyclic antibiotic lipopeptides such as iturins. <![CDATA[<B>Efficient transformation of <I>Penicillium chrysogenum</I> mediated by <I>Agrobacterium tumefaciens</I> LBA4404 for cloning of <I>Vitreoscilla</I> hemoglobin gene</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100009&lng=es&nrm=iso&tlng=es The vgb and bleomycin resistance genes could be efficiently transferred into the filamentous fungus Penicillium chrysogenum under help of T-DNA of Agrobacterium tumefaciens LBA4404 and the transferred genes were integrated at a chromosomal locus of P. chrysogenum. Transformation using A. tumefaciens LBA4404 could be enhanced in the presence of acetosyringone (AS) when being carried out in the conidiaand mycelium. The efficiencies of transformation could be improved up to 10 folds compared with conventional techniques for transformation of P. chrysogenum protoplasts. <![CDATA[Catalase enzyme in mitochondria of Saccharomyces cerevisiae]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100010&lng=es&nrm=iso&tlng=es Catalase and superoxide dismutase activities have been explored in the yeast Saccharomyces cerevisiae during batchwise growth experiment. During the diauxic growth in YPD medium high Ys values were obtained (0.415 - 0.423) and correlation between the total activities of both enzymes has been found. A mitochondrial fraction from three type strains of Saccharomyces cerevisiae has been isolated. The purity of this fraction was proved through different enzyme assays: hexokinase, glucose-6-phosphate dehydrogenase, D-amino acid oxidase, isocitric lyase, succinate dehydrogenase. Then the catalase, peroxidase, Mn and Cu/Zn superoxide dismutase activities were evaluated in the mitochondrial fraction. Polyacrylamide gel electrophoresis separations allowed to identify a mitochondrial catalase as a band of 0.239 Rm value. It differed from the two catalase specific bands with Rm values 0.218 and 0.257 obtained from the crude extract. It was proved that the three catalase proteins are charge isomers. A positive correlation between the activity of mitochondrial catalase and Mn superoxide dismutase also takes place. Molecular weight of mitochonrial catalase protein has been determined as 240 kD. <![CDATA[<B>Application of rice (<I>Oryza sativa</I> L.) suspension culture in studying senescence <I>in vitro</I> (I).</B>: <B>Single strand preferring nuclease activity</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100011&lng=es&nrm=iso&tlng=es Single Strand-Preferring Nucleases (SSPNs) have been implicated in the triggering and progress of cell death pathways, including senescence in higher plants, though the biological roles of such enzymes are still obscure. In the present study, heterotrophic cell suspension cultures of Oryza sativa L. (rice) cv Taipei 309 were used to investigate changes in Single Strand-Preferring Nuclease activity associated with cell death in vitro. An acid nuclease activity (pH 5.5) was found which was strongly stimulated in the presence of 10 mM Zn2+ and inhibited by 10 mM EDTA and EGTA. An increase in SSPN activity was concomitant with a loss of cell viability, total protein and the onset of stationary phase of growth in the cell cultures. Using DNA-SDS-PAGE two major SSPNs were detected with the molecular weights of 26 KDa and 53.5 KDa. There are possibilities that these two enzymes represent monomeric and dimeric forms of the same nuclease or they are two different enzymes. The 26 KDa nuclease was partially purified using heparin-Sepharose column chromatography. The results confirm the value of plant cell suspension cultures for the investigation of the molecular process underlying plant cell ageing, senescence processes and programmed cell death (PCD). Possible senescence-associated roles of SSPNs are discussed. <![CDATA[<B>Application of rice (<I>Oryza sativa</I> L.) suspension culture in studying senescence <I>in vitro</I> (II). </B>: <B>Changes in DNA integrity</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100012&lng=es&nrm=iso&tlng=es Changes in the DNA content and organisation of senescing rice cell cultures (Taipei 309) were studied, using PCR and Southern blot analyses. A mitochondrial gene (coxII), a plastid gene (psaA) and a nuclear DNA maker (RG64) were analysed. The amplification of mitochondrial (mt), plastid and nuclear DNA produced the expected fragments, indicating that there were still some intact organelles and nuclei in the senescing rice cells. However, in plastid and nuclear DNA, changes in the number and size of the PCR products were observed. Southern blot analysis revealed that mt and nuclear DNA contents declined, but plastid DNA content remained relatively the same throughout the senescence. <![CDATA[<B>Biotechnology and the developing world</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100013&lng=es&nrm=iso&tlng=es The life sciences offer opportunities for revolutionizing human welfare activities. Enriched by inputs from genomic research, biotechnology is a major force for development in all countries. Entwined with culture and socio-ethical values, biotechnology contributes to solving problems like food and water insecurity that impede national development and threaten peace in the developing world. The lack of facilities and professional skills in biotechnology limits R & D initiatives in the developing and the least developed countries (LDCs); and, restricts their full participation in take-off activities in national and self-reliant regional ventures in sustainable development. The practice of biotechnology different in many developing countries is nevertheless impressive. The establishment of biotechnology parks and medicinal plant farms in several developing countries is indicative of biotechnology being accorded high policy status in national development; of its significance in the eradication of poverty; and of its use in the empowerment of women in applying the technology for human and social welfare. This review provides several examples of different types of biotech activities that are being employed for development in the developing world. <![CDATA[<B>Plant protease inhibitors in control of phytophagous insects</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100014&lng=es&nrm=iso&tlng=es Plant proteinase inhibitors (PIs) have been well established to play a potent defensive role against predators and pathogens. Although diverse endogenous functions for these proteins has been proposed, ranging from regulators of endogenous proteinases to act as storage proteins, evidence for many of these roles is partial, or confined to isolated examples. On the other hand, many PIs have been shown to act as defensive compounds against pests by direct assay or by expression in transgenic crop plants, and a body of evidence for their role in plant defense has been accumulated consistently. The role and mechanism of action for most of these inhibitors are being studied in detail and their respective genes isolated. These genes have been used for the construction of transgenic crop plants to be incorporated in integrated pest management programmes. This article describes the classes of protease inhibitors, their regulation and genes used to construct transgenic plants against phytophagous insects.