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  • Open Access

    ARTICLE

    Brief Note : Proacrosin-acrosin activity in capacitated and acrosome reacted sperm from cryopreserved bovine semen

    M. I. ROSATTI, M. T. BECONI, M. CÓRDOBA

    BIOCELL, Vol.28, No.3, pp. 311-316, 2004, DOI:10.32604/biocell.2004.28.311

    Abstract Acrosin activity is associated with normal fertility in human and bovine spermatozoa. The aim of the study was to determine the variation of the enzyme activity in the proacrosin-acrosin system in capacitated and acrosome reacted cryopreserved bovine sperm. Enzyme activity was assessed spectrophotometrically using N-α-benzoyl-DL-arginine p-nitroanilide (BAPNA) as specific substrate for acrosin at pH 8. Capacitation with heparin and quercitin failed to induce conversion of proacrosin to acrosin. An increase in acrosin activity produced by the presence of progesterone, in a dose-dependent manner, was related with the induction of true acrosome reaction. The total level More >

  • Open Access

    ARTICLE

    Karyotype description of Pomacea patula catemacensis (Caenogastropoda, Ampullariidae), with an assessment of the taxonomic status of Pomacea patula

    MARÍA ESTHER DIUPOTEX-CHONG1, NÉSTOR J. CAZZANIGA2, ALEJANDRA HERNÁNDEZ-SANTOYO3, JOSÉ MIGUEL BETANCOURT-RULE4

    BIOCELL, Vol.28, No.3, pp. 279-285, 2004, DOI:10.32604/biocell.2004.28.279

    Abstract Mitotic chromosomes of the freshwater snail Pomacea patula catemacensis (Baker 1922) were analyzed on gill tissue of specimens from the type locality (Lake Catemaco, Mexico). The diploid number of chromosomes is 2n = 26, including nine metacentric and four submetacentric pairs; therefore, the fundamental number is FN = 52. No sex chromosomes could be identified. The same chromosome number and morphology were already reported for P. flagellata, i.e., the other species of the genus living in Mexico. The basic haploid number for family Ampullariidae was reported to be n° =°14 in the literature; so, its reduction to More >

  • Open Access

    ARTICLE

    Radial Basis Function and Genetic Algorithms for Parameter Identification to Some Groundwater Flow Problems

    B. Amaziane1, A. Naji2, D. Ouazar3

    CMC-Computers, Materials & Continua, Vol.1, No.2, pp. 117-128, 2004, DOI:10.3970/cmc.2004.001.117

    Abstract In this paper, a meshless method based on Radial Basis Functions (RBF) is coupled with genetic algorithms for parameter identification to some selected groundwater flow applications. The treated examples are generated by the diffusion equation with some specific boundary conditions describing the groundwater fluctuation in a leaky confined aquifer system near open tidal water. To select the best radial function interpolation and show the powerful of the method in comparison to domain based discretization methods, Multiquadric (MQ), Thin-Plate Spline (TPS) and Conical type functions are investigated and compared to finite difference results or analytical one. More >

  • Open Access

    ARTICLE

    Some Aspects of the Method of Fundamental Solutions for Certain Biharmonic Problems

    Yiorgos-Sokratis Smyrlis1, Andreas Karageorghis1

    CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.5, pp. 535-550, 2003, DOI:10.3970/cmes.2003.004.535

    Abstract In this study, we investigate the application of the Method of Fundamental Solutions for the solution of biharmonic Dirichlet problems on a disk. Modifications of the method for overcoming sources of inaccuracy are suggested. We also propose an efficient algorithm for the solution of the resulting systems which exploits the symmetries of the matrices involved. The techniques described in the paper are applied to standard test problems. More >

  • Open Access

    REVIEW

    Review : Reticulocyte maturation: mitoptosis and exosome release

    CHARLES GÉMINARD, AUDE DE GASSART, MICHEL VIDAL

    BIOCELL, Vol.26, No.2, pp. 205-215, 2002, DOI:10.32604/biocell.2002.26.205

    Abstract During the differentiation of erythroid cells, a vast program of maturation takes place, leading to decay or elimination of organelles, including the nucleus, mitochondria, ribosomes, lysosomes, endoplasmic reticulum and Golgi apparatus. During the last step of red cell maturation, remaining organelles, primarily mitochondria and ribosomes but also vestiges of others are finally cleared from the cell. This cleaning session also affects specific proteins that are partially or entirely removed from the cell surface. The interplay of the various events and their causal relationships are approached here. More >

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