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| Registros recuperados: 978 | |
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| White,Gilbert; Seffens,William. |
| A neural network (NN) was trained on amino and nucleic acid sequences to test the NNs ability to predict a nucleic acid sequence given only an amino acid sequence. A multi-layer backpropagation network of one hidden layer with 5 to 9 neurons was used. Different network configurations were used with varying numbers of input neurons to represent amino acids, while a constant representation was used for the output layer representing nucleic acids. In the best-trained network, 93% of the overall bases, 85% of the degenerate bases, and 100% of the fixed bases were correctly predicted from randomly selected test sequences. The training set was composed of 60 human sequences in a window of 10 to 25 codons at the coding sequence start site. Different NN... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000300009 |
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| Crouch,Jonathan H.; Vuylsteke,Dirk; Ortiz,Rodomiro. |
| Bananas and plantains (Musa spp.) are the most important tropical fruit crops. They form an integral component of the farming systems in the humid agroecological zones of the tropics. A broad array of applied cell and molecular techniques are increasingly being used worldwide to facilitate and enhance the handling and improvement of plantain and banana germplasm. Tissue culture is used for germplasm exchange, conservation and rapid multiplication, while in vitro seed germination (based on embryo culture or rescue) plays a critical role in generating hybrid plants. DNA marker systems have been developed in Musa to assist germplasm management, selection within the breeding pool or gene introgression from wild species, and for disease diagnosis. Likewise,... |
| Tipo: Journal article |
Palavras-chave: Banana; Improvement; Micropropagation; DNA; Markers; Plantain. |
| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000100002 |
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| Canales,Mauricio; Lobos,Sergio; Vicuña,Rafael. |
| Ceriporiopsis subvermispora is a white-rot basidiomycete that produces several isoenzymes of manganese peroxidase (MnP· ). A cDNA of one of them (MnP13-1) has been isolated and sequenced. The deduced aminoacid sequence shows about 60% similarity with the MnPs from Phanerochaete chrysosporium. Based on the crystal structures of MnP and lignin peroxidase (LiP) from P. chrysosporium, and of a peroxidase from Arthromyces ramosus (ARP), we have modeled by homology the three dimensional structure of MnP13-1 using standard modeling procedures. Local molecular mechanics optimization performed in the region corresponding to the binding sites of Ca2+ and Mn2+ in MnP13-1 demonstrated that the stereochemistry and the geometry of binding are conserved in both MnPs. A... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000200006 |
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| Damiano,Carmine; Monticelli,Simona. |
| Agrobacterium rhizogenes infection at the base of microcuttings in vitro can improve the rooting of some fruit species. A study was carried out comparing rooting of almond, apple, plum, Pyrus pyraster and two hybrid rootstocks, when infected with A. rhizogenes strain 1855, with and without the addition of hormones. Three responses occurred: genotypes rooted without auxins; genotypes rooted only with auxins; genotypes rooted only after infection. All genotypes rooted after bacterial infection. In the first group the auxins increased rooting percentages. No substantial differences were found with and without infection in hormone free media, while the rooting percentages tended to decrease with the combination auxin/infection. In the second group, infection... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000300008 |
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| Carvalho,Cristina M. L.; Aires-Barros,Maria Raquel; Cabral,Joaquim M. S.. |
| This review analyses the role of cutinases in nature and their potential biotechnological applications. The cloning and expression of a fungal cutinase from Fusarium solani f. pisi, in Escherichia coli and Saccharomyces cerevisiae hosts are described. The three dimensional structure of this cutinase is also analysed and its function as a lipase discussed and compared with other lipases. The biocatalytic applications of cutinase are described taking into account the preparation of different cutinase forms and the media where the different types of enzymatic reactions have been performed, namely hydrolysis, esterification, transesterification and resolution of racemic mixtures. The stability of cutinase preparations is discussed, particularly in anionic... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000300006 |
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| Perlin,David S.. |
| The development of an effective target for therapeutic intervention remains a critical part of the drug discovery process. One such target class is the P-type ion translocating ATPases, which include the Na+,K+-ATPase of cardiac cells and the H+,K+-ATPase of gastric parietal cells. These enzymes serve as selective targets for digoxin and omeprazole, which are used to treat heart disease and gastrointestinal ulcers, and are two of the leading prescribed therapeutics worldwide. It is the exquisite selectivity that can be achieved between family members that continues to make the P-type enzymes desirable targets for developing new therapeutics including a new generation of antiulcer therapeutic and a new class of antifungal therapeutic. |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000200002 |
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| Brink,Johan A; Woodward,Barbara R; DaSilva,Edgar J. |
| Africa is, paradoxically, a continent rich in resources, and yet, lacking and lagging in overall development. When the wealth of Africas people is compared with that of other continents a contrasting picture of poverty, stunted growth and famine resulting from inadequate food production is revealed. Applying plant biotechnology alone cannot solve the agricultural and food security problems in Africa. Five key factors seem to be necessary for the improvement of crop production: they are the use of agrochemicals, irrigation, plant breeding, farm management, and, of course, plant biotechnology. In this context, biotechnology can play a role in commercializing crops, creating new jobs and earning foreign exchange. The goals of national and regional... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000300004 |
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| Malaurie,Bernard; Trouslot,Marie-France; Berthaud,Julien; Bousalem,Mustapha; Pinel,Agnès; Dubern,Jean. |
| Yam edible tubers feed million of peoples in the intertropical area, where they represent 12% of human feeding. However, as a vegetatively propagated crop, yam is seriously affected by an accumulation of pathogens. Establishing in vitro germplasm collection is a process that cleans the plants from all diseases but viruses. It gives a good control on the preservation of the yam genetic resources and facilitates international exchanges of healthy plant material. Two kinds of in vitro germplasm preservation were considered : slow growth condition culture for mid-term preservation, and cryopreservation using the encapsulation/dehydration technique for long-term preservation. Virus eradication was approached by meristem culture and chemo and thermotherapy.... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000300001 |
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| Raimbault,Maurice. |
| At first some general considerations about specificity and characteristics of SSF, their advantages and disadvantages as compared to LSF, are presented. Microorganisms involved in solid substrate fermentations are identified, considering the better performances of filamentous fungi. The solid substrates and their basic macromolecular compounds are detailed in relation to this complex and heterogeneous system. Biomass measurement is examined in detail, as well as environmental factors, both essential for studying and optimising solid substrate fermentations. |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000300007 |
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| Chan,Edward K.L.; Fritzler,Marvin J.. |
| Autoantibodies directed against self-antigens are characteristic features of a number of human diseases. In systemic rheumatic diseases, these include antibodies that react with extracellular molecules; the cell membrane; nuclear and cytoplasmic components. Our laboratories have been interested in understanding autoimmune responses in systemic lupus erythematosus and related disease states and using human autoantibody as molecular probes in studying the cell biology of target antigens. This review summarizes our research efforts in dissecting the autoimmune response to the Golgi complex via expression cloning using human autoantibodies. We have cloned 4 of 5 known Golgi autoantigens that are referred to as golgin-95/GM130, golgin-97, golgin-160/GCP170, and... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000200001 |
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| Igloi,Gabor L. |
| Rapid, large-scale genome as well as diagnostic DNA sequencing projects are, at present, dependent on the use of sensitive automated sequencers that rely on the detection of fluorescent signals. This emission is not an intrinsic property of the biomolecules but is a property of an optical label that must be incorporated before, during or after the sequence specific reaction. The choice of strategy, that is to be reviewed here, is a function of both the chemistry and the enzymology of the system as well as the nature of the fractionation and the physical parameters of the detection. One may differentiate beween the labelling of the primer, incorporation of the label during elongation or base specific termination with labelled terminators. In reviewing the... |
| Tipo: Journal article |
Palavras-chave: Automated sequencing; Non-radioactive labelling; Nucleic acid analysis. |
| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000100003 |
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| Bustamante,Pedro I.; Hull,Roger. |
| Plant viruses can cause serious losses to most, if not all, major crops upon which depend for food. Many viruses are endemic, causing moderate losses each year. Others, such as those causing rice tungro, give periodic severe epidemics. There are no fully collated figures for world-wide losses due to viruses but some examples has been listed, i.e., rice tungro in SE ASIA and african cassava mosaic in Africa with 1,500 and 2,000 millions dollars per year in losses respectively. However, in recent years the understanding of the genome organisation of plant viruses has increased in parallel with development of molecular biological techniques. The ability to obtain nucleotide sequences of complete viral genomes has also permitted the elucidation and... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000200003 |
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| Yang,Yea-Tyng; Bennett,George N; San,Ka-Yiu. |
| Recent advances in molecular biology techniques, analytical methods and mathematical tools have led to a growing interest in using metabolic engineering to redirect metabolic fluxes for industrial and medical purposes. Metabolic engineering is referred to as the directed improvement of cellular properties through the modification of specific biochemical reactions or the introduction of new ones, with the use of recombinant DNA technology (<A HREF="#56">Stephanopoulos, 1999</A>). This multidisciplinary field draws principles from chemical engineering, biochemistry, molecular and cell biology, and computational sciences. The aim of this article is to give an overview of the various strategies and tools available for metabolic engineers and to... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000300003 |
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| Montaldo,Hugo H.; Meza-Herrera,Cesar A.. |
| Recent developments in molecular biology and statistics have opened the possibility of identifying and using genomic variation and major genes for the genetic improvement of livestock. Information concerning the basis of these techniques and their applications to the genetic improvement of animals is reviewed. Main marker molecular marker systems in animals (RFPL and microsatellites), genome maps, methods for detecting marker major gene linkages and use of marker assisted selection, genetic fingerprinting and mixture models based on segregation analysis are analyzed. The characteristics where the application of marker assisted selection can be more effective are those that are expressed late in the life of the animal, or controlled by a few pairs of genes.... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000200004 |
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| Daza,Camilo. |
| It is well known that the number of researchers in Biotechnology in Latin America and the Caribbean is too small to cope with the needs of research and to successfully confront the number of short and long-term problems. The United Nations University created its Biotechnology Program for Latin America and the Caribbean, UNU/BIOLAC, and the results of the efforts aiming to the promotion of a shared sense of direction within the region´s scientific community are presented and discussed herein. |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000200005 |
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| Ortiz,Rodomiro. |
| This article reviews some of the highlights of modern plant biotechnology and discusses the potential applications of biotechnology in the betterment of farming systems in the next millennium. Plant biotechnology will facilitate the farming of crops with multiple durable resistance to pests and diseases, particularly in the absence of pesticides. Likewise, transgenes or marker-assisted selection may assist in the development of high yielding crops, which will be needed to feed the world and save land for the conservation of plant biodiversity in natural habitats. Hence, crops should be engineered to meet the demands and needs of consumers. The genetic base of crop production can be preserved and widen by an integration of biotechnology tools in... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000300005 |
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| Registros recuperados: 978 | |
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