173 research outputs found

    Genetic diversity and coefficient of parentage between clones and sugarcane varieties in Brazil

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    The success of the development of new sugarcane varieties is associated with the ability to correctly select the genitor. The aim of this study was to evaluate the genetic diversity between 113 clones and sugarcane varieties using the Ward-modified location model procedure with added information about the coefficient of parentage and endogamy. In this study, data was used from 100 experiments that evaluated clones; the experimental phase was conducted in 70 places between the years 2002 and 2009 on the outlining in random blocks. According to the diversity analysis, 3 groups formed: G1, G2, and G3, which were composed of 58, 8, and 47 genotypes, respectively. The clones of groups G1 and G3 were the most outstanding. Thus, biparental crossbreeding involving clones and varieties of these 2 groups can efficiently obtain transgressive genotypes. Knowledge of the heterotypic groups indicated by the Ward-modified location model method, along with the parentage information, will make it a lot easier to define the desirable and undesirable crossbreeds for public and private breeding programs that develop sugarcane varieties

    Measuring Electrical And Mechanical Properties Of Red Blood Cells With A Double Optical Tweezers

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    The fluid lipid bilayer viscoelastic membrane of red blood cells (RBC) contains antigen glycolproteins and proteins which can interact with antibodies to cause cell agglutination. This is the basis of most of the immunohematologic tests in blood banks and the identification of the antibodies against the erythrocyte antigens is of fundamental importance for transfusional routines. The negative charges of the RBCs creates a repulsive electric (zeta) potential between the cells and prevents their aggregation in the blood stream. The first counterions cloud strongly binded moving together with the RBC is called the compact layer. This report proposes the use of a double optical tweezers for a new procedure for measuring: (1) the apparent membrane viscosity, (2) the cell adhesion, (3) the zeta potential and (4) the compact layer's size of the charges formed around the cell in the electrolytic solution. To measure the membrane viscosity we trapped silica beads strongly attached to agglutinated RBCs and measured the force to slide one RBC over the other as a function of the relative velocity. The RBC adhesion was measured by slowly displacing two RBCs apart until the disagglutination happens. The compact layer's size was measured using the force on the silica bead attached to a single RBC in response to an applied voltage and the zeta potential was obtained by measuring the terminal velocity after releasing the RBC from the optical trap at the last applied voltage. We believe that the methodology here proposed can improve the methods of diagnosis in blood banks.6326Eylar, E.H., Madoff, M.A., Brody, O.V., Oncley, J.L., The contribution of sialic acid to the surface charge of the erythrocyte (1962) J. Biol. Chem., 237, pp. 1992-2000Pollack, W., Reckel, R.P., A reappraisal of the forces involved in Hemagglutination (1977) Int Archs Allergy Appl. Immun., 54, pp. 29-42Ashkin, A., Dziedzic, J.M., Bjorkholm, J.E., Chu, S., Observation of a single-beam gradient force trap for dielectric particles (1986) Opt. Lett., 11, pp. 288-290Ashkin, A., Dziedzic, J.M., Optical trapping and manipulation of viruses and bacteria (1987) Science, 235, pp. 1517-1520Grier, D.G., A revolution in optical manipulation (2003) Nature, 424, pp. 810-816Zhu, C., Bao, G., Wang, N., Cell Mechanics: Mechanical response, cell adhesion, and molecular deformation (2000) Annu. Rev. Biomed. Eng., 2, pp. 189-226Neuman, K.C., Block, S., Optical trapping (2004) Rev. Sci. Instrum., 75, pp. 2787-2809Saffman, P.G., Delbruck, M., Brownian motion in biological membranes (1975) Proc. Nat. Acad. Sci. USA, 72, pp. 3111-3113Dimova, R., Danov, K., Pouligny, B., Ivanov, I.B., Drag of a solid particle trapped in a thin film or at an interface: Influence of surface viscosity and elasticity (2000) J. Colloid and Interface Science, 226, pp. 35-43Hochmuth, R., Worthy, P., Evans, E., Red cell extensional recovery and the determination of membrane viscosity (1979) Biophys. J., 26, pp. 101-114Sze, A., Erickson, D., Ren, L., Li, D., Zeta-potential measurement using the Smoluchowski equation and the slope of the current-time relationship in electroosmotic flow (2003) J. Colloid and Interface Science, 261, pp. 402-410Hunter, R.J., (1981) Zeta Potential in Colloid Science, , Academic Press, New YorkPollack, W., Hager, H.J., Reckel, R., Toren, D.A., Singher, H.O., A study of the forces involved in the second stage of hemaggltination (1965) Transfusion, 5, pp. 158-183Chelidze, T., Dielectric spectroscopy of blood (2002) J. Non-crystalline Solids, 305, pp. 285-294Hymer, W.C., Barlow, G.H., Blaisdell, S.J., Continuous flow electrophoretic separation of proteins and cells from mammalian tissues (1987) Cell Biophys., 10, pp. 61-85Hashimoto, N., Fujita, S., Yokoyama, T., Cell electrophoretic mobility and glycerol lysis of human erythrocytes in various diseases (1998) Electrophoresis, 19, pp. 1227-123

    Nutrição mineral de hortaliças: XXXII. marcha de absorção dos nutrientes pelo tomateiro (Lycopersicon esculentum Mill,) destinado ao processamento industrial

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    In order to find out the concentration of macro and micronutrients, as well the total amounts of nutrients absorved by Roma VF, of the Santa Cruz group of tomato, plants were collected from field from 15 days up to 105 days and analysed for the nutrients. At the flowering period the leaves presented the following concentration on nutrients: 3.7% N; 0.5% P; 3.2% Ca; 0,9% Mg; 0,4% S; 72 ppm B; 15 ppm Cu; 434 ppm Fe; 375 ppm Mn; 0.1 ppm Mo and 148 ppm Zn. A production of 65 t/ha effective hasrvested content: 67.8 kg N; 8.9 kg P; 112.2 kg K; 7.7 kg Ca; 6.0 kg Mg; 3.1 kg S; 93 g B; 45 g Cu; 547 g Fe; 163 g Mn; 485 mg Mo; 321 g Zn.Reveste-se de grande importância o conhecimento da marcha de absorção de nutrientes pelas culturas, principalmente visando uma aplicação racional dos fertilizantes. Utilizou-se no presente experimento a cultivar Roma VF, de porte determinado, que tem tido grande aceitação tanto pelos tomaticultores como pelas industrias processadoras. As amostras para analise foram coletadas no período junho a outubro de 1977, em uma área experimental instalada num solo representativo da região oeste do Estado de São Paulo (Latossol Vermelho Amarelo), no município de Narandiba (DIRA de Presidente Prudente)· A cultura recebeu uma adubação de 85--300-100 kg/ha de NPK, sendo 1/3 do N aplicado juntamente com todo o P e K no plantio e os 2/3 restantes aplicados em cobertura aos 30 e 35 dias após a germinação. A área foi de 1,25 x 0,30 m (26,666 covas/ha), com culturais foram os normalmente recomendados para a cultura na região. As amostras (4 repetições) foram coletadas aos 15, 30, 45, 60, 75, 90 e 105 dias após a germinação. As plantas foram separadas em folhas cotiledonares, folhas, caule e frutos. Determinou-se o peso de matéria seca e analisou-se para N, P, K, Ca, Mg, S, B, Cu, Fe, Mo e Zn. Os resultados analíticos obtidos revelaram um crescimento lento ate aos 30 dias, após o que houve um crescimento acelerado, com o peso da materia seca praticamente dobrando a cada quinzena no período dos 45 aos 75 dias, atingindo o máximo aos 105 dias (5.706,61 kg/ha). Quanto ao crescimento dos frutos, expresso em peso de materia seca, houve um aumento de cerca de 20 vezes no intervalo dos 45 aos 75 dias, praticamente duplicando o peso no período dos 75 aos 90 dias e estabilizando-se aos 105 dias (2.708,6 kg/ha). Na época de floração, as folhas apresentavam, em função da materia seca, 3,7% N; 0,50% P; 4,44% K; 3,24% Ca; 0,99% Mg; 0,46% S; 72 ppm B; 15 ppm Cu; 434 ppm Fe; 375 ppm Mn; 0,18 ppm Mo; 148 ppm Zn. A produção efetiva de 65 ton/ha obtida na área experimental, contem as seguintes quantidades de nutrientes nos frutos: 67,8 g N; 8,9 g P; 112,2g K; 7,7 g Ca; 6,0 g Mg; 3,1 g S; 93 g B; 45 g Cu; 547 g Fe; 163 g Mn; 485 mg Mo

    Studying Red Blood Cell Agglutination By Measuring Membrane Viscosity With Optical Tweezers

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    The red blood cell (RBC) viscoelastic membrane contains proteins and glycoproteins embedded in a fluid lipid bilayer that are responsible for cell agglutination. Manipulating RBCs rouleaux with a double optical tweezers, we observed that the cells slide easily one over the others but are strongly connected by their edges. An explanation for this behavior could be the fact that when the cells slide one over the others, proteins are dragged through the membrane. It confers to the movement a viscous characteristic that is dependent of the velocity between the RBCs and justifies why is so easy to slide them apart. Therefore, in a first step of this work, by measuring the force as a function of the relative velocity between two cells, we confirmed this assumption and used this viscous characteristic of the RBC rouleaux to determine the apparent membrane viscosity of the cell. As this behavior is related to the proteins interactions, we can use the apparent membrane viscosity to obtain a better understanding about cell agglutination. Methods related to cell agglutination induced by antigen-antibody interactions are the basis of most of tests used in transfusion centers. Then, in a second step of this work, we measured the apparent membrane viscosity using antibodies. We observed that this methodology is sensitive to different kinds of bindings between RBCs. Better comprehension of the forces and bindings between RBCs could improve the sensibility and specificity of the hemagglutination reactions and also guides the development of new potentiator substances.6644Fontes, A., Fernandes, H.P., Barjas-Castro, M.L., Thomaz, A.A., Pozzo, L., Barbosa, L.C., Cesar, C.L., Red blood cell membrane viscoelasticity, agglutination and zeta potential measurements with double optical tweezers (2006) Proceedings of SPIE, 6088, pp. 296-305Eylar, E.H., Madoff, M.A., Brody, O.V., Oncley, J.L., The contribution of sialic acid to the surface charge of the erythrocyte (1962) J. Biol. Chem, 237, pp. 1992-2000Pollack, W., Reckel, R.P., A reappraisal of the forces involved in Hemagglutination (1977) Int Archs Allergy Appl. Immun, 54, pp. 29-42Fontes, A., Giorgio, S., de Castro Jr., A.B., Neto, V.M., Pozzo, L.Y., Marques, G.P., Barbosa, L.C., Cesar, C.L., Determination of femto Newton forces and fluid viscosity using optical tweezers: Application to Leishmania amazonensis (2005) Proceedings of SPIE, 5699, pp. 419-425Saffman, P.G., Delbruck, M., Brownian motion in biological membranes (1975) Proc. Nat. Acad. Sci. USA, 72, pp. 3111-3113Dimova, R., Danov, K., Pouligny, B., Ivanov, I.B., Drag of a solid particle trapped in a thin film or at an interface: Influence of surface viscosity and elasticity (2000) J. Colloid and Interface Science, 226, pp. 35-4

    Optical Tweezers And Multiphoton Microscopies Integrated Photonic Tool For Mechanical And Biochemical Cell Processes Studies

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    The research in biomedical photonics is clearly evolving in the direction of the understanding of biological processes at the cell level. The spatial resolution to accomplish this task practically requires photonics tools. However, an integration of different photonic tools and a multimodal and functional approach will be necessary to access the mechanical and biochemical cell processes. This way we can observe mechanicaly triggered biochemical events or biochemicaly triggered mechanical events, or even observe simultaneously mechanical and biochemical events triggered by other means, e.g. electricaly. One great advantage of the photonic tools is its easiness for integration. Therefore, we developed such integrated tool by incorporating single and double Optical Tweezers with Confocal Single and Multiphoton Microscopies. This system can perform 2-photon excited fluorescence and Second Harmonic Generation microscopies together with optical manipulations. It also can acquire Fluorescence and SHG spectra of specific spots. Force, elasticity and viscosity measurements of stretched membranes can be followed by real time confocal microscopies. Also opticaly trapped living protozoas, such as leishmania amazonensis. Integration with CARS microscopy is under way. We will show several examples of the use of such integrated instrument and its potential to observe mechanical and biochemical processes at cell level.6644Denk, W., Strickler, J.H., Webb, W.W., (1990) Science, 248, p. 73Xu, C., (1996) Proc. Natl. Acad. Sci. USA, 93, pp. 10-763Minami, T., Hirayama, S., (1990) J. Photochem. Photobiol. A - Chem, 53 (1), p. 11Lakowicz, J.R., Berndt, K.W., (1991) Rev. Scientific Instrum, 62 (7), p. 1727Becker, W., (2004) Microscopy Res. Technique, 63 (1), p. 58Ha, T., (1996) PNAS, 93 (13), p. 6264Gordon, G.W., (1998) Biophysical J, 74 (5), p. 2702Szavo, G., (1992) Biophysical J, 61 (3), p. 661Campagnola, P.G., (1999) Biophysical J, 77 (6), p. 3341J. X. Cheng JX and X. S. Xie, J. Physical Chem. B 108 (3): 827 (2004)M. Muller et al, J. Microscopy 197, 150 Part 2 (2000)Goksör, M., Enger, J., Hanstorp, D., Optical manipulation in combination with multiphoton microscopy for single-cell studies (2004) Applied Optics, 43 (25), p. 4831Ajito, K., Morita, M., (1999) Surf. Science, 428, p. 141Jess, P.R.T., Garces-Chavez, V., Smith, D., Mazilu, M., Paterson, L., Riches, A., Herrington, C.S., Dholakia, K., (2006) Opt. Express, 14 (12), p. 5779Fontes, A., Ajito, K., De Paula, A.M., Neves, A.R., Moreira, W.L., Barbosa, L.C., Cesar, C.L., (2003) Microsc. Microanal, 9 (SUPPL. 2), pp. 164-165A. Fontes, K. Ajito, A. A. R. Neves, W. L. Moreira, A. A. Thomaz, L. C. Barbosa, A. M. de Paula and C. L. Cesar, Phys. Rev. E. 72, 012903 (1-4) (2005)Fontes, A., Neves, A.A.R., Moreira, W.L., de Thomaz, A.A., Barbosa, L.C., de Paula, A.M., Cesar, C.L., (2005) Appl. Phys. Lett, 87, p. 22110

    Topological and geometrical restrictions, free-boundary problems and self-gravitating fluids

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    Let (P1) be certain elliptic free-boundary problem on a Riemannian manifold (M,g). In this paper we study the restrictions on the topology and geometry of the fibres (the level sets) of the solutions f to (P1). We give a technique based on certain remarkable property of the fibres (the analytic representation property) for going from the initial PDE to a global analytical characterization of the fibres (the equilibrium partition condition). We study this analytical characterization and obtain several topological and geometrical properties that the fibres of the solutions must possess, depending on the topology of M and the metric tensor g. We apply these results to the classical problem in physics of classifying the equilibrium shapes of both Newtonian and relativistic static self-gravitating fluids. We also suggest a relationship with the isometries of a Riemannian manifold.Comment: 36 pages. In this new version the analytic representation hypothesis is proved. Please address all correspondence to D. Peralta-Sala

    Applied aspects of pineapple flowering

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