I.Quantum dot-based immunochemistry of P. falciparum infected erythrocytes. We used quantum dots in an immunocytochemical approach to quantify band 3 modifications in P. falciparum-infected hemoglobin C erythrocytes. This work was directed to an elucidation of the innate protection mechanisms against severe malaria in various hemoglobin types. We found that all infected erythrocytes irrespective of hemoglobin genotype (normal AA and a mutant CC erythrocytes) have increased band 3 clustering, but the phenomenon was more profound in CC erythrocytes. This increased band 3 cluster size in CC erythrocytes may enhance autoantibody recognition of abnormal erythrocytes play a major role in the innate protection mechanism exhibited by hemoglobin C individuals. II. Quantitative AFM study of the effects of hemoglobin type on a Plasmodium falciparum-infection. Irrespective of hemoglobin genotype, parasites may induce knob-like projections on the erythrocyte surface. The knobs play a major role in the adherence of P. falciparum-infected erythrocytes to microvascular endothelia. A major peak with a width of ~70 nm in all infected erythrocytes. In parasitized AC and CC erythrocytes, however, a second larger knob population with a peak of ~120 nm was present. The large knob population size increased as the parasites matured. III. Chemo-attraction of malaria sporozoites to mosquito salivary glands. We developed a method using GFP-labeled sporozoites to demonstrate that the sporozoites respond chemotactically to mosquito salivary gland homogenate. The chemical nature of the attractant remains to be determined.

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National Institute of Allergy and Infectious Diseases (NIAID)
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Tokumasu, Fuyuki; Ostera, Graciela R; Amaratunga, Chanaki et al. (2012) Modifications in erythrocyte membrane zeta potential by Plasmodium falciparum infection. Exp Parasitol 131:245-51
Tokumasu, Fuyuki; Nardone, Glenn A; Ostera, Graciela R et al. (2009) Altered membrane structure and surface potential in homozygous hemoglobin C erythrocytes. PLoS One 4:e5828
Ostera, Graciela; Tokumasu, Fuyuki; Oliveira, Fabiano et al. (2008) Plasmodium falciparum: food vacuole localization of nitric oxide-derived species in intraerythrocytic stages of the malaria parasite. Exp Parasitol 120:29-38
Calvo, Eric; Tokumasu, Fuyuki; Marinotti, Osvaldo et al. (2007) Aegyptin, a novel mosquito salivary gland protein, specifically binds to collagen and prevents its interaction with platelet glycoprotein VI, integrin alpha2beta1, and von Willebrand factor. J Biol Chem 282:26928-38
Hayakawa, Eri; Tokumasu, Fuyuki; Nardone, Glenn A et al. (2007) A Mycobacterium tuberculosis-derived lipid inhibits membrane fusion by modulating lipid membrane domains. Biophys J 93:4018-30
Arie, Takayuki; Fairhurst, Rick M; Brittain, Nathaniel J et al. (2005) Hemoglobin C modulates the surface topography of Plasmodium falciparum-infected erythrocytes. J Struct Biol 150:163-9
Tokumasu, Fuyuki; Fairhurst, Rick M; Ostera, Graciela R et al. (2005) Band 3 modifications in Plasmodium falciparum-infected AA and CC erythrocytes assayed by autocorrelation analysis using quantum dots. J Cell Sci 118:1091-8
Tokumasu, Fuyuki; Hwang, Jeeseong; Dvorak, James A (2004) Heterogeneous molecular distribution in supported multicomponent lipid bilayers. Langmuir 20:614-8
Tokumasu, F; Dvorak, J (2003) Development and application of quantum dots for immunocytochemistry of human erythrocytes. J Microsc 211:256-61
Dvorak, James A; Kobayashi, Seiki; Nozaki, Tomoyoshi et al. (2003) Induction of permeability changes and death of vertebrate cells is modulated by the virulence of Entamoeba spp. isolates. Parasitol Int 52:169-73

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