Browsing by Author "Gutierrez, M"

Now showing 1 - 4 of 4
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    Association of primary antiphospholipid syndrome with primary adrenal insufficiency
    (J RHEUMATOL PUBL CO, 1996) Gonzalez, G; Gutierrez, M; Ortiz, M; Tellez, R; Figueroa, F; Jacobelli, S
    The association of primary adrenal insufficiency with antiphospholipid antibodies is usually reported in the context of adrenal thrombosis or hemorrhage. We describe a 35-year-old woman who developed a primary antiphospholipid syndrome (spontaneous abortion, thrombocytopenia, and cerebrovascular occlusion) in association with primary adrenal insufficiency without evidence of suprarenal hemorrhage or thrombosis.
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    Enhanced resistance to bacterial infection by Erwinia carotovora subsp atroseptica in transgenic potato plants expressing the attacin or the cecropin SB-37 genes
    (1999) Arce, P; Moreno, M; Gutierrez, M; Gebauer, M; Dell'Orto, P; Torres, H; Acuña, I; Oliger, P; Venegas, A; Jordana, X; Kalazich, J; Holuigue, L
    Blackleg and soft rot diseases, caused by the bacterium Erwinia carotovora, are among the diseases that cause important losses in culture and storage of potato. In this paper, we introduced bacterial resistance into potato, via genes encoding for proteins with antibacterial activity. For this purpose, potato clones were transformed either with the gene encoding the acidic attacin protein from Hyalophora cecropia, or with the gene encoding the cecropin analog peptide SB-37. These clones were evaluated for soft rot and blackleg resistance, after inoculation with the bacterial strain Erwinia carotovora subsp. atroseptica T7. Results reported in this paper indicate that a considerable percentage of the potato clones (15-22%) showed increased resistance to bacterial infection, revealed by reduced severity of blackleg or soft rot symptoms. Expression of the transgenes was demonstrated in some of the clones by Northern blot analysis. This is the first report indicating that. expression of the gene encoding for an attacin protein and for the cecropin SB-37 peptide in transgenic potato confers increased resistance to bacterial infection.
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    Expression of the chicken lysozyme gene in potato enhances resistance to infection by Erwinia carotovora subsp, Atroseptica
    (2000) Serrano, C; Arce-Johnson, P; Torres, H; Gebauer, M; Gutierrez, M; Moreno, M; Jordana, X; Venegas, A; Kalazich, J; Holuigue, L
    Infection of potato plants and tubers with the bacterium Erwinia carotovora subsp, atroseptica produces blackleg and soft rot diseases, which cause significant losses to crops and stored potatoes. In order to obtain resistance against this bacterium, the gene chly encoding the enzyme lysozyme from chicken was introduced into potato plants (cv. Desiree) via Agrobacterium-mediated transformation. Sixty-three and 69 transgenic potato clones were evaluated in the greenhouse for resistance to blackleg and soft rot diseases, respectively. Results reported in this paper indicate that 21%-29% of the potato clones showed increased resistance to infection by the bacterium E. c, subsp, atroseptica T7, as revealed by a reduced severity of blackleg or soft rot symptoms. Nine clones showing different levels of resistance were selected for further molecular analysis. The number of copies of the transgene integrated in the plant genome of these clones was estimated by Southern blot analysis. The level of transgene expression, detected by Northern blot analysis, correlated with the level of resistance detected in these clones.
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    Survivable capacitated network design problem: new formulation and Lagrangean relaxation
    (PALGRAVE MACMILLAN LTD, 2000) Rios, M; Marianov, V; Gutierrez, M
    This work is focused on the analysis of the survivable capacitated network design problem. This problem can be stated as follows: Given a supply network with point-to-point traffic demands, specific survivability requirements, a set of available capacity ranges and their corresponding discrete costs for each are, find minimum cost capacity expansions such that these demands can be met even if a network component fails. Solving this problem consists of selecting the links and their capacity, as well as the routings for each demand in every failure situation. This type of problem can be shown to be NP-hard. A new linear mixed-integer mathematical programming formulation is presented. An effective solution procedure based on Lagrangean relaxation is developed. Comparison heuristics and improvement heuristics are also described. Computational results using these procedures on different sizes of randomly generated networks are reported.