Non-linear Micro-spectroscopy In An Optical Tweezers System: Application To Cells Marked With Quantum Dots

In this work we used our set up consisting of an optical tweezers plus non-linear micro-spectroscopy system to perform scanning microscopy and observe spectra using two photon excited (TPE) luminescence of captured single cells conjugated with quantum dots of CdS and CdTe. The CdS nanocrystals are obtained by our group via colloidal synthesis in aqueous medium with final pH = 7 using sodium polyphosphate as the stabilizing agent. In a second step the surface of CdS particles is functionalized with linking agents such as Glutaraldehyde. The CdTe quantum dots are functionalized in the its proper synthesis using mercaptoacetic acid (AMA). We used a femtosecond Ti:sapphire laser to excite the hyper Rayleigh or TPE luminescence in particles trapped with an Nd:YAG cw laser and a 30 cm monochromator equipped with a cooled back illuminated CCD to select the spectral region for imaging. With this system we obtained hyper Rayleigh and TPE luminescence images of macrophages and other samples. The results obtained show the potential presented by this system and fluorescent labels to perform spectroscopy in a living trapped microorganism in any neighbourhood and dynamically observe the chemical reactions changes in real time.5700273278Ashkin, A., Dziedzic, J.M., Optical trapping and manipulation of viruses and bacteria (1987) Science, 235, pp. 1517-1520Sakata-Sogawa, K., Direct measurement of DNA molecular length in solution using optical tweezers: Detection of looping due to binding protein interactions (1998) Eur. J Biophy, 27, pp. 55-61Konig, K., Determination of motility forces of human spermatozoa using an 800nm optical trap (1996) Cell. Mol. Biol., 42, pp. 501-509Konig, K., Laser tweezers and multiphoton microscopes in life sciences (2000) Hyst. and Cell Biol., 114, pp. 79-91Borchert, H., Talapin, D.V., McGinley, C., High resolution photoemission study of CdSe and CdSe/ZnS core-shell nanocrystals (2003) J. Chem. Phys., 271, pp. 1800-1807Alivisatos, A.P., Semiconductor clusters, nanocrystals, and quantum dots (1996) Science, 271, pp. 933-937Nowak, C., Döllefeld, H., Eychmüller, A., Innershell absorption spectroscopy on CdS: Free clusters and nanocrystals (2001) J. Chem. Phys., 114, pp. 489-494Eychmuller, A., Structure and photophysics of semiconductor nanocrystals (1996) J. Phys Chem. B., 59, pp. 13226-13239Bruchez Jr., M., Moronne, M., Gin, P., Weiss, S., Alivisatos, A.P., Semiconductor nanocrystals as fluorescent biological labels (1998) Science, 281, pp. 2013-2016Chan, W.C.W., Nie, S., Quantum dots for ultrasensitive biological detection (1998) Science, 281, pp. 2016-2018Ballou, B., Lagerholm, B.C., Ernst, L.A., Bruchez, M.P., Waggoner, A.S., Noninvasive imaging of quantum dots in mice (2004) Bioconjug. Chem., 15, pp. 79-86Gao, X., Nie, S., Molecular profiling of single cells and tissue specimens with quantum dots (2003) Trends Biotechnol., 21, pp. 371-373Äkerman, M.E., Chan, W.C.W., Laakkonen, P., Bhatia, S.N., Ruoslahti, E., Nanocrystal targeting in vivo (2002) Appl. Biol. Sci., 99, pp. 12617-12621Chan, W.C.W., Maxwell, D.J., Gao, X., Bailey, R.E., Han, M., Shuming, N., Luminescent quantum dots for multiplexed biological detection and imaging (2002) Curr. Op. Bioteh., 13, pp. 40-46Mattheakis, L.C., Dias, J.M., Choi, Y., Gong, J., Bruchez, M.P., Liu, J., Wang, E., Optical coding of mammalian cells using semiconductor quantum dot (2004) Anal Biochem., 327, pp. 200-208Petrov, D.V., Santos, B.S., Pereira, G.A.L., Donegá, C.M., Size and band-gap dependences of the hiperpolarizability of CdxZn1-xS nanocrystals (2002) J. Phys. Chem. B, 106, pp. 5325-5334Ajito, K., Torimitsu, K., Single nanoparticle trapping using a Raman tweezers microscope (2002) Applied Spectroscopy, 56, pp. 541-544Xie, C.G., Dinno, M.A., Li, Y.Q., Near-infrared Raman spectroscopy of single optically trapped biological cells (2002) Optics Letters, 27, pp. 249-251Wood, B.R., Tait, B., McNaughton, D., Micro-Raman characterisation of the R to T State transition of haemoglobin within a single living erythrocyte (2001) Bioch. et Biophys. Acta, 1539, pp. 58-7

Studying Taxis In Real Time Using Optical Tweezers: Applications For Leishmania Amazonensis Parasites

Beads trapped by an optical tweezers can be used as a force transducer for measuring forces of the same order of magnitude as typical forces induced by flagellar motion. We used an optical tweezers to study chemotaxis by observing the force response of a flagellated microorganism when placed in a gradient of attractive chemical substances. This report shows such observations for Leishmania amazonensis, responsible for leishmaniasis, a serious disease. We quantified the movement of this protozoan for different gradients of glucose. We were able to observe both the strength and the directionality of the force. The characterization of the chemotaxis of these parasites can help to understand the mechanics of infection and improve the treatments employed for this disease. This methodology can be used to quantitatively study the taxis of any kind of flagellated microorganisms under concentration gradients of different chemical substances, or even other types of variable gradients such as temperature and pressure. © 2009 Elsevier Ltd. All rights reserved.405-6617620Adler, J., A method for measuring chemotaxis and use of the method to determine optimum conditions for chemotaxis by Escherichia coli (1973) J. Gen. Microbiol., 74, pp. 77-91Allersma, M.W., Gittes, F., de Castro, M.J., Stewart, R.J., Schmidt, C.F., Two-dimensional tracking of ncd motility by back focal plane interferometry (1998) Biophys. J., 74, pp. 1074-1085Ashkin, A., Dziedzic, J., Bjorkholm, J., Chu, S., Observation of a single-beam gradient force optical trap for dielectric particles (1986) Opt. Lett., 11, pp. 288-290Barros, V.C., Oliveira, J.S., Melo, M.N., Gontijo, N.F., Leishmania amazonensis: chemotaxic and osmotaxic responses in promastigotes and their probable role in development in the phlebotomine gut (2006) Exp. Parasitol., 112, pp. 152-157Blair, D.F., How bacteria sense and swim (1999) Annu. Rev. Microbiol., 49, pp. 489-522Bleul, C.C., Farzan, M., Choe, H., Parolin, C., Clark-Lewis, I., Sodroski, J., Springer, T.A., The lymphocyte chemoattractant SDF-1 is a ligand for LESTR/fusin and blocks HIV-1 entry (1996) Nature, 382, pp. 829-833Bray, R.S., Leishmaniachemotaxic responses of promastigotes and macrophages in vitro (1983) J. Protozool., 30, pp. 322-329Bustamante, C., Bryant, Z., Smith, S.B., Ten years of tension: single-molecule DNA mechanics (2003) Nature, 421, pp. 423-427Fontes, 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 femtonewton forces and fluid viscosity using optical tweezers: application to Leishmania amazonensis (2005) Proc. SPIE, 5699, pp. 419-425Gittes, F., Schmidt, C.F., Interference model for back-focal-plane displacement detection in optical tweezers (1998) Opt. Lett., 23, pp. 7-9Gontijo, B., Carvalho, M.L.R., Leishmaniose tegumentar Americana (2003) Rev. Soc. Bras. Med. Trop., 36, pp. 71-80Handman, E., Cell biology of Leishmania (2000) Adv. Parasitol., 44, pp. 1-39Khan, S., Jain, S., Reid, G.P., Trentham, D.R., The fast tumble signal in bacterial chemotaxis (2004) Biophys. J., 86, pp. 4049-4058Law, A.M.J., Aitken, M.D., Continuous-flow capillary assay for measuring bacterial chemotaxis (2005) Appl. Environ. Microbiol., 71, pp. 3137-3143Leslie, G., Barrett, M., Burchmore, R., Leishmania mexicana: promastigotes migrate through osmotic gradients (2002) Exp. Parasitol., 102, pp. 117-120Nagasawa, T., Hirota, S., Tachibana, K., Takakura, N., Nishikawa, S., Kitamura, Y., Yoshida, N., Kishimoto, T., Defects of B-cell lymphopoiesis and bone-marrow myelopoiesis in mice lacking the CXC chemokine PBSF/SDF-1 (1996) Nature, 382, pp. 635-638Nelson, R.D., Quie, P.G., Simmons, R.L., Chemotaxis under agarose-new and simple method for measuring chemotaxis and spontaneous migration of human polymorphonuclear leukocytes and monocytes (1975) J. Immunol., 115, pp. 1650-1656Neuman, K.C., Chadd, E.H., Liou, G.F., Bergman, K., Block, S.M., Characterization of photodamage to Escherichia coli in optical traps (1999) Biophys. J., 77, pp. 2856-2863Pfeffer, W., (1888) Unters. Botan. Inst. Tubingen, 2, pp. 582-661Rao, C.V., Glekas, G.D., Ordal, G.W., The three adaptation systems of Bacillus subtilis chemotaxis (2008) Trends Microbiol., 16, pp. 480-487Rice, S.E., Purcell, T.J., Spudich, J.A., Building and using optical traps to study properties of molecular motors (2003) Biophotonics, 361, pp. 112-133Rohrbach, A., Stelzer, E.H.K., Three-dimensional position detection of optically trapped dielectric particles (2002) J. Appl. Phys., 91, pp. 5474-5488World Health Organization, (2002) Annex 3: Burden of Disease in DALYs by Cause, Sex and Mortality Stratum in WHO Regions, Estimates for 2001. The World Health report, , WHO, Geneva pp. 192-19

Synthesis And Characterization Of Cdte Nanocrystals For Applications As Biolabels

Semiconductor nanocrystals composed by few hundred to a few thousand atoms also known as quantum dots have received substantial attention due to their size tunable narrow-emission spectra and several other advantages over organic molecules as fluorescent labels for biological applications, including resistence to photodegradation, improved brightness and only one laser excitation that enable the monitoring of several processes simultaneously. In this work we have synthesized and characterized thiol-capped CdTe and bioconjugated them to macrophages. We have mapped the fluorescence intensity along the macrophage's body in our set up consisting of an optical tweezer plus a non-linear micro-spectroscopy system to perform scanning microscopy and observe spectra using two photon excited luminescence.5704193199Borchert, H., Talapin, D.V., McGinley, C., High resolution photoemission study of CdSe and CdSe/ZnS coreshell nanocrystals (2003) J. Chem. Phys., 271, pp. 1800-1807Alivisatos, A.P., Semiconductor clusters, nanocrystals, and quantum dots (1996) Science, 271, pp. 933-937Nowak, C., Döllefeld, H., Eychmüller, A., Innershell absorption spectroscopy on CdS: Free clusters and nanocrystals (2001) J. Chem. Phys., 114, pp. 489-494Bruchez Jr., M., Moronne, M., Gin, P., Weiss, S., Alivisatos, A.P., Semiconductor nanocrystals as fluorescent biological labels (1998) Science, 281, pp. 2013-2016Chan, W.C.W., Nie, S., Quantum dots for ultrasensitive biological detection (1998) Science, 281, pp. 2016-2018Ballou, B., Lagerholm, B.C., Ernst, L.A., Bruchez, M.P., Waggoner, A.S., Noninvasive imaging of quantum dots in mice. Bioconjug (2004) Chem., 15, pp. 79-86Gao, X., Nie, S., Molecular profiling of single cells and tissue specimens with quantum dots (2003) Trends Biotechnol., 21, pp. 371-373Äkerman, M.E., Chan, W.C.W., Laakkonen, P., Bhatia, S.N., Ruoslahti, E., Nanocrystal targeting in vivo (2002) Appl. Biol. Sci., 99, pp. 12617-12621Chan, W.C.W., Maxwell, D.J., Gao, X., Bailey, R.E., Han, M., Shuming, N., Luminescent quantum dots for multiplexed biological detection and imaging (2002) Curr. Op. Bioteh., 13, pp. 40-46Mattheakis, L.C., Dias, J.M., Choi, Y., Gong, J., Bruchez, M.P., Liu, J., Wang, E., Optical coding of mammalian cells using semiconductor quantum dot (2004) Anal Biochem., 327, pp. 200-208Konig, K., Laser tweezers and multiphoton microscopes in life sciences (2000) Hyst. and Cell Biol., 114, pp. 79-91Goodman, M.M., Knapp Jr., F.F., (1983) Organometallics, 2, pp. 1106-1108Gaponik, N., Talapin, D.V., Rogach, A.L., Hoppe, K., Shevchenko, E.V., Kornowski, A., Eychmüller, A., Weller, H., Thiol-capping of cdte nanocrystals: An alternative to organometallic synthetic routes (2002) J. Phys. Chem. B, 106, pp. 7177-7718Rosenthal, S.J., Tomlinson, I., Adkins, E.M., Schroeter, S., Adams, S., Swafford, L., McBride, J., Blakely, R., Targeting cell surface receptors with ligand-conjugated nanocrystals (2002) J. Am. Chem. Soc., 124, pp. 4586-459

High Fluorescent And Stable Semiconductor Quantum Dots For Red Blood Cells Labeling

We present a simple and efficient method for marking living human red blood cells using CdS (Cadmium Sulfide) quantum dots (QDs). The nanocrystals were obtained via colloidal synthesis in aqueous medium with final pH=7 using sodium polyphosphate as the stabilizing agent. The methodology implementation is simple, do not requires additional capping layers nor narrow size QDs distribution. The synthesized nanoparticles were conjugated to monoclonal A anti-body. The resulting conjugates QDs/anti-A were incubated with human erythrocytes of blood groups A and O for 30 min at 37°C. The living cells in contact with the quantum dots maintained their properties for several days showing the low level of citotoxicity of the quantum dots. The conjugation of CdS QDs/anti-A show simultaneous red and green fluorescence when excited with 543 and 488 nm respectively. The efficiency of the conjugation QDs/anti-body to the erythrocytes, for each system, was monitored by confocal microscopy. The comparative analysis of the micrographs was done with the luminescence intensity maps of the samples obtained under constant capture conditions, such as, pinhole, filters, beam splitters and photomultiplier gain. The conjugates QDs/anti-A intensely marked group A erythrocytes and did not show any luminescence for group O erythrocytes, showing the sensitivity of the labeling procedure. In conclusion, we show the viability of the use of high luminescent and stable quantum dots as fluorescent labels for human erythrocytes with a methodology of simple implementation and the possibility to use them to distinguish different blood groups.57048692Borchert, H., Talapin, D.V., McGinley, C., High resolution photoemission study of CdSe and CdSe/ZnS core-shell nanocrystals (2003) J. Chem. Phys., 271, pp. 1800-1807Alivisatos, A.P., Semiconductor clusters, nanocrystals, and quantum dots (1996) Science, 271, pp. 933-937Nowak, C., Döllefeld, H., Eychmüller, A., Innershell absorption spectroscopy on CdS: Free clusters and nanocrystals (2001) J. Chem. Phys., 114, pp. 489-494Eychmuller, A., Structure and photophysics of semiconductor nanocrystals (1996) J. Phys Chem. B., 59, pp. 13226-13239Bruchez Jr., M., Moronne, M., Gin, P., Weiss, S., Alivisatos, A.P., Semiconductor nanocrystals as fluorescent biological labels (1998) Science, 281, pp. 2013-2016Chan, W.C.W., Nie, S., Quantum dots for ultrasensitive biological detection (1998) Science, 281, pp. 2016-2018Ballou, B., Lagerholm, B.C., Ernst, L.A., Bruchez, M.P., Waggoner, A.S., Noninvasive imaging of quantum dots in mice (2004) Bioconjug. Chem., 15, pp. 79-86Gao, X., Nie, S., Molecular profiling of single cells and tissue specimens with quantum dots (2003) Trends Biotechnol., 21 (9), pp. 371-373Äkerman, M.E., Chan, W.C.W., Laakkonen, P., Bhatia, S.N., Ruoslahti, E., Nanocrystal targeting in vivo (2002) Appl. Biol. Sci., 99 (20), pp. 12617-12621Chan, W.C.W., Maxwell, D.J., Gao, X., Bailey, R.E., Han, M., Shuming, N., (2002) Curr. Op. Bioteh., 13 (1), pp. 40-46Mattheakis, L.C., Dias, J.M., Choi, Y., Gong, J., Bruchez, M.P., Liu, J., Wang, E., Optical cding of mammalian cells using semiconductor quantum dot (2004) Anal Biochem., 327, pp. 200-208Tokumasu, F., Dvorak, J., Development and application of quantum dots for immunocytochemistry of human erythrocytes (2003) J Microsc., 211, pp. 256-261Hoshino, A., Hanaki, K.-I., Suzuki, K., Yamamoto, K., Applications of T-lymphoma labeled with fluorescent quantum dots to cells tracing markers in mouse body (2004) Biochem. Biophys. Res. Comm., 314, pp. 46-53Petrov, D.V., Santos, B.S., Pereira, G.A.L., Donegá, C.M., Size and band-gap dependences of the hiperpolarizability of CdxZn1-xS nanocrystals (2002) J. Phys. Chem. B, 106 (21), pp. 5325-5334Daniels, G., (2002) Human Blood Groups, , Oxford, UK: Blackwell ScienceTaylor, D.L., Waggoner, A.S., Murphy, R.F., Lanni, F., Birge, R.R., (1986) Applications of Fluorescent in the Biomedical Sciences, , New York, USA: Alan R. Liss, IncLarson, D.R., Zipfel, W.R., Williams, R.M., Clark, S.W., Bruchez, M.P., Wise, F.W., Webb, W.W., Water soluble quantum dots for multiphoton fluorescence imaging in vivo (2003) Science, 300, pp. 1434-143

Molecular Differentiation Of Leishmania Protozoarium Using Cds Quantum Dots As Biolabels

In this work we applied core-shell CdS/Cd(OH)2 quantum dots (QDs) as fluorescent labels in the Leishmania amazonensis protozoarium. The nanocrystals (8-9 nm) are obtained via colloidal synthesis in aqueous medium, with final pH=7 using sodium polyphosphate as the stabilizing agent. The surface of the particles is passivated with a cadmium hydroxide shell and the particle surface is functionalized with glutaraldehyde. The functionalized and non-functionalized particles were conjugated to Leishmania organisms in the promastigote form. The marked live organisms were visualized using confocal microscopy. The systems exhibit a differentiation of the emission color for the functionalized and non-functionalized particles suggesting different chemical interactions with the promastigote moieties. Two photon emision spectra (λexc=795nm) were obtained for the promastigotes labeled with the functionalized QDs showing a significant spectral change compared to the original QDs suspension. These spectral changes are discussed in terms of the possible energy deactivation processes.6097Medinitz, I.L., Tetsuo Uyeda, H., Goldman, E.R., Mattoussi, H., Quantum dot bioconjugates for imaging, labeling and sensing (2005) Nature Materials, 4, pp. 435-446Chen, F., Gerion, D., Fluorescent CdSe/ZnS nanocrystal-peptide conjugates for long-term, nontoxic imaging and nuclear targeting in living cells (2004) Nano Letters, 4 (10), pp. 27-1832Alivisatos, A.P., Semiconductor clusters, nanocrystals, and quantum dots (1996) Science, 271, pp. 933-937Medintz, I.L., Konnert, J.H., Clapp, A.R., Stanish, I., Twigg, M.E., Mattoussi, H., A fluorescence resonance energy transfer-derived structure of a quantum dot-protein bioconjugate nanoassembly PNAS, 101 (26), pp. 9612-9617Mamedova, N.N., Kotov, N.A., Rogach, A.L., Studer, J., Albumin-CdTe nanoparticle bioconjugates: Preparation, structure, and interunit energy transfer with antenna effect (2001) Nano Lett., 1, pp. 281-286Farias, P.M.A., Santos, B.S., De Menezes, F.D., Ferreira, R.C., Barjas-Castro, M.L., Castro, V., Moura Lima, P.R., Cesar, C.L., Investigation of red blood cell antigens with highly fluorescent and stable semiconductor quantum dots (2005) Journal of Biomedical Optics, 10 (4), pp. 440231-1044234Farias, P.M.A., Santos, B.S., De Menezes, F.D., Ferreira, R.C., Barjas-Castro, M.L., Castro, V., Moura Lima, P.R., Cesar, C.L., Core-shell CdS/Cd(OH)2 quantum dots: Synthesis and bioconjugation to target red cells antigens (2005) Journal of Microscopy, 219 (3), pp. 103-108Petrov, D.V., Santos, B.S., Pereira, G.A.L., Donegá, C.M., Size and band-gap dependences of the hiperpolarizability of CdxZnl-xS nanocrystals (2002) J. Phys. Chem. B, 106, pp. 5325-5334Santos, B.S., (2002) Obtenção de Nanopartículas de CdS em Sistemas Amorfos e a Investigação de suas Propriedades Ópticas Não-lineares em Meio Aquoso, , Doctoral Thesis, Recife, BrazilSolomons, G., Fhryle, C., (2004) Organic Chemistry, 7th Ed., , Wiley, New YorkGao, X.M., Rhodes, J., An essential role for constitutive Schiff base-forming ligands in antigen presentation to murine T cell clones (1990) The Journal of Immunology, 144 (8), pp. 2883-2890Silveira, T.G.V., Arraes, S.M.A.A., Bertolini, D.A., Teodora, U., Lonardoni, M.V.C., Roberto, A.C.B.S., Sobrinho, M.R., Shaw, J., Observações sobre o diagnóstico laboratorial e a epidemiologia da leishmaniose tegumentar no Estado do Paraná, sul do Brasil (1999) Revista da Sociedade Brasileira de Medicina Tropical, 32 (4), pp. 413-42

Optical Tweezers For Studying Taxis In Parasites

In this work we present a methodology to measure force strengths and directions of living parasites with an optical tweezers setup. These measurements were used to study the parasites chemotaxis in real time. We observed behavior and measured the force of: (i)Leishmania amazonensis in the presence of two glucose gradients; (ii)Trypanosoma cruzi in the vicinity of the digestive system walls, and (iii)Trypanosoma rangeli in the vicinity of salivary glands as a function of distance. Our results clearly show a chemotactic behavior in every case. This methodology can be used to study any type of taxis, such as chemotaxis, osmotaxis, thermotaxis, phototaxis, of any kind of living microorganisms. These studies can help us to understand the microorganism sensory systems and their response function to these gradients. © 2011 IOP Publishing Ltd.134DPDx-Trypanosomiasis, American. Fact Sheet. Centers for Disease Control (CDC). Retrieved 2008-09-11(2002), WHO, World Health OrganizationGrisard, E.C., Moraes, M.H., Guarneri, A.A., Girardi, F.P., Rodrigues, J.B., Eger-Mangrich, I., Tyler, K.M., Steindel, M., Different serological cross-reactivity of Trypanosoma rangeli forms in Trypanosoma cruzi-infected patients sera (2008) Parasites Vectors, 1 (1), p. 20Bagorda, A., Parent, C.A., Eukaryotic chemotaxis at a glance (2008) J. Cell Sci., 121 (16), pp. 2621-2624Teves, M.E., Guidobaldi, H.A., Ũates, D.R., Sanchez, R., Miska, W., Publicover, S.J., Morales Garcia, A.A., Giojalas, L.C., Molecular mechanism for human sperm chemotaxis mediated by progesterone (2009) PLoS ONE, 4 (12), p. 8211Snchez, R., Seplveda, C., Risopatrón, J., Villegas, J., Giojalas, L.C., Human sperm chemotaxis depends on critical levels of reactive oxygen species (2010) Fertil Steril., 93 (1), pp. 150-153Wu, J.Y., Feng, L., Park, H.-T., Havlioglu, N., Wen, L., Tang, H., Bacon, K.B., Rao, Y., The neuronal repellent Slit inhibits leukocyte chemotaxis induced by chemotactic factors (2001) Nature, 410 (6831), pp. 948-952. , DOI 10.1038/35073616Zheng, M., Sun, G., Cai, S., Mueller, R., Mrowietz, U., Significant reduction of T-cell chemotaxis to MCP-1 in patients with primary and metastatic melanoma (1999) Chin. Med. J. (Engl.), 112, pp. 493-496Kohidai, L., Chemotaxis: The proper physiological response to evaluate phylogeny of signal molecules (1999) Acta Biologica Hungarica, 50 (4), pp. 375-394Law, A.M.J., Aitken, M.D., Continuous-flow capillary assay for measuring bacterial chemotaxis (2005) Applied and Environmental Microbiology, 71 (6), pp. 3137-3143. , DOI 10.1128/AEM.71.6.3137-3143.2005Khan, S., Jain, S., Reid, G.P., Trentham, D.R., The fast tumble signal in bacterial chemotaxis (2004) Biophysical Journal, 86 (6), pp. 4049-4058. , DOI 10.1529/biophysj.103.033043Neuman, K.C., Chadd, E.H., Liou, G.F., Bergman, K., Block, S.M., Characterization of photodamage to Escherichia coli in optical traps (1999) Biophysical Journal, 77 (5), pp. 2856-2863Bleul, C.C., Farzan, M., Choe, H., Parolin, C., Clark-Lewis, I., Sodroski, J., Springer, T.A., The lymphocyte chemoattractant SDF-1 is a ligand for LESTR/fusin and blocks HIV-1 entry (1996) Nature, 382 (6594), pp. 829-833. , DOI 10.1038/382829a0Nagasawa, T., Hirota, S., Tachibana, K., Takakura, N., Nishikawa, S.-I., Kitamura, Y., Yoshida, N., Kishimoto, T., Defects of B-cell lymphopoiesis and bone-marrow myelopoiesis in mice lacking the CXC chemokine PBSF/SDF-1 (1996) Nature, 382 (6592), pp. 635-638. , DOI 10.1038/382635a0Nelson, R.D., Quie, P.G., Simmons, R.L., Chemotaxis under agarose-new and simple method for measuring chemotaxis and spontaneous migration of human polymorphonuclear leukocytes and monocytes (1975) J. Immunol., 115, pp. 1650-1656Blair, D.F., How bacteria sense and swim (1999) Annu. Rev. Microbiol., 49 (1), pp. 489-522Rao, C.V., Glekas, G.D., Ordal, G.W., The three adaptation systems of Bacillus subtilis chemotaxis (2008) Trends Microbiol., 16 (10), pp. 480-487Barros, V.C., Oliveira, J.S., Melo, M.N., Gontijo, N.F., Leishmania amazonensis: Chemotaxic and osmotaxic responses in promastigotes and their probable role in development in the phlebotomine gut (2006) Experimental Parasitology, 112 (3), pp. 152-157. , DOI 10.1016/j.exppara.2005.10.005, PII S0014489405002572Pfeffer, W., (1888) Unters. Botan. Inst. Tubingen, 2, pp. 582-661Adler, J., A method for measuring chemotaxis and use of the method to determine optimum conditions for chemotaxis by Escherichia coli (1973) J. Gen. Microbiol., 74, pp. 77-91Pozzo, L.Y., Fontes, A., De Thomaz, A.A., Santos, B.S., Farias, P.M., Ayres, D.C., Giorgio, S., Cesar, C.L., Studying taxis in real time using optical tweezers: Applications for Leishmania amazonensis parasites (2009) Micron, 40 (5-6), pp. 617-620Chagas, C., Nova tripanosomiase humana (1909) Mem. Inst. Oswaldo Cruz., 1, pp. 1-62Nogueira, N.F.S., Gonzales, M., Garcia, E.M., De Souza, W., Effect of azadirachtin A on the fine structure of the midgut of Rhodnius prolixus (1997) Journal of Invertebrate Pathology, 69 (1), pp. 58-63Gonzalez, M.S., Hamedi, A., Albuquerque-Cunha, J.M., Nogueira, N.F.S., De Souza, W., Ratcliffe, N.A., Azambuja, P., Mello, C.B., Antiserum against perimicrovillar membranes and midgut tissue reduces the development of Trypanosoma cruzi in the insect vector, Rhodnius prolixus (2006) Experimental Parasitology, 114 (4), pp. 297-304. , DOI 10.1016/j.exppara.2006.04.009, PII S0014489406001044Alves, C.R., Albuquerque-Cunha, J.M., Mello, C.B., Garcia, E.S., Nogueira, N.F., Bourguingnon, S.C., De Souza, W., Gonzalez, M.S., Trypanosoma cruzi: Attachment to perimicrovillar membrane glycoproteins of Rhodnius prolixus (2007) Experimental Parasitology, 116 (1), pp. 44-52. , DOI 10.1016/j.exppara.2006.11.012, PII S0014489406003171Gomes, S.A.O., Souza, A.L.F., Kiffer, T.M., Dick, C.F., Santos, A.L.A., Meyer-Fernandes, J.R., Ecto-phosphatase activity on the external surface of Rhodnius prolixus salivary glands: Modulation by carbohydrates and Trypanosoma rangeli (2008) Acta Trop., 106 (2), pp. 137-142Vallejo, G.A., Guhl, F., Schaub, G.A., Triatominae-Trypanosoma cruzi/T. rangeli: Vector-parasite interactions (2009) Acta Trop., 110 (2-3), pp. 137-147Happel, J., Brenner, H., (1991) Low Reynolds Number Hydrodynamics with Special Applications to Particulate Media(1971) Handbook of Chemistry and PhysicsDe Thomaz, A.A., Optical tweezers force measurements to study parasites chemotaxis (2009) Proc. SPIE, 7367, pp. 73671