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• Virginijus Barzda - Associate Professor
EMAIL: vbarzda [at] utm.utoronto.ca
I am working in the field of biophysics of complex biological systems. My research is aimed to obtain fundamental knowledge on physical mechanisms that determine the function and dynamics of proteins, assemblies of pigment-protein-lipid complexes, cell organelles and whole cells. I am studying single proteins and individual cells by means of non-linear optical microscopy and microvolume spectroscopy. We applied this technique to study spectroscopic and structural properties of chloroplasts and stomata from plants, myocytes from cardiac muscle and neuron cells.
My work involves the development of new types of optical microscopy by employing non-linear contrast mechanisms. We are building simultaneous detection second- and third-harmonic generation and multi-photon excitation fluorescence microscope. The far-field microscope is combined with near-field scanning probe and atomic force microscope. We complement microvolume measurements with other steady state and time resolved spectroscopic techniques.
1996 Ph.D. Biological Research Center, J�zsef Attila University, Szeged, Hungary
Physics and Biophysics
1991 M.Sc. Vilnius University, Vilnius, Lithuania
Physics and Biophysics
Department of Physics, University of Toronto
� Investigation of structural-functional dynamics in biological organisms with non-linear microscopy and nano-spectroscopy.
� Time-resolved spectroscopic studies of single molecules and pigment-protein complexes
� Development of new methods for non-linear microscopy
Assistant Project Scientist
The Wilson-Squier Group, Department of Chemistry and Biochemistry, University of California, San Diego
� Established basis for imaging mitochondria of myocytes and chloroplasts with third harmonic generation microscope
� Researched anti-bleaching effect of quantum dots
� Developed time-resolved fluorescence, second and third harmonic generation microscopy.
Post-doctoral Fellow, European Molecular Biology Organization (EMBO) and Dutch Foundation for Scientific Research (NWO)
Biophysics Group, Department of Physics and Astronomy, Vrije Universiteit Amsterdam,
� Revealed large heterogeneity of fluorescence quenching inside individual aggregates of light-harvesting pigment-protein complex of photosystem II (LHCII) from plants.
� Established basis for singlet-singlet and singlet-triplet annihilation microscopy and applied that for correlation between size of connectivity domain and its quenching properties in aggregate of LHCII.
� Discovered fluorescence quenching processes in LHCII, ranging from microseconds to hundreds of milliseconds.
� Investigated influence of aggregation on the excited triplet state formation in LHCII and revealed residual chlorophylls that do not transfer their triplets to carotenoids.
� Obtained the evidence for slow excitation energy migration in light-harvesting antenna of photosystem II.
Scientific Co-worker and PhD student
Laboratory for Thylakoid Membrane Energization, Institute of Plant Biology, Biological Research Center, Szeged, Hungary
� Researched aggregation dependent spectroscopic properties of light-harvesting antenna from green plants.
� Discovered light-induced structural changes in LHCII and correlated with non-photochemical quenching in green plants.
� Performed kinetic and thermodynamic investigation on light-induced quenching in LHCII aggregates.
� Revealed long-range excitation energy migration in aggregates of LHCII.
� Investigated spectroscopic properties of LHCII aggregates with different macrostructures that are determined by different content of thylakoid lipids.
Laboratory of Optoelectronic, Physics Institute, Vilnius, Lithuania.
� Investigated ultrafast excitation energy transfer between porphyrins and quinones.
Lampoura, S.S., Barzda, V., Owen, G.M., Hoff, A.J., van Amerongen, H., (2002) Aggregation of LHCII leads to a redistribution of the triplets over the central xanthophylls in LHCII, Biochemistry, 41: 9139-9144.
Barzda, V., Grauw C.J., Vroom, J.M., Kleima, F.J., van Amerongen, H., van Grondelle, R. and Gerritsen, H., (2001) Fluorescence lifetime heterogeneity in aggregates of LHCII revealed by time resolved microscopy, Biophys. J., 81: 538-546.
Barzda, V., Gulbinas, V., Kananavicius, R., Cervinskas, V., van Amerongen H., van Grondelle, R. and Valkunas, L., (2001) Singlet-Singlet Annihilation Kinetics in Aggregates and Trimers of LHCII, Biophys. J., 80: 2409-2421.
Gussakovsky, E. E., Shahak, Y., van Amerongen, H. and Barzda, V., (2000) Circularly polarized chlorophyll luminescence reflects the macro-organization of grana in pea chloroplasts, Photosynth. Res., 65: 83-92.
Barzda, V., Vengris, M., Valkunas, L., van Grondelle, R., van Amerongen, H. (2000) Generation of fluorescence quenchers from the triplet states of chlorophylls in the major light-harvesting complex II from green plants, Biochemistry, 39(N34):10468-10477.
Barzda, V., Jennings, R., Zucchelli and Garab, G. (1999) Kinetic analysis of the light-induced fluorescence quenching in light-harvesting chlorophyll a/b pigment-protein complex of photosystem II, Photochem. Photobiol., 70(N5):751-759.
Simidjiev, I., Barzda, V., Mustardy, L., and Garab, G. (1998) Role of thylakoid lipids in the structural flexibility of lamellar aggregates of the isolated light-harvesting chlorophyll a/b complex of photosystem II, Biochemistry, 37(12): 4169-4173.
Barzda, V., Peterman, E.J.G., van Grondelle, R. and van Amerongen, H. (1998) The influence of aggregation on triplet formation in light-harvesting chlorophyll a/b pigment-protein complex II of green plants, Biochemistry, 37(2): 546-551.
Gussakovsky, E.E., Barzda, V., Shahak, Y. and Garab G. (1997) Irreversible disassembly of chiral macrodomains in thylakoids due to photoinhibition, Photosynth. Res., 51(2):119-126.
Simidjiev, I., Barzda, V., Mustardy, L. and Garab G. (1997) Isolation of lamellar aggregates of the light-harvesting chlorophyll a/b protein complex of photosystem II with long-range chiral order and structural flexibility, Anal. Biochem., 250(2):169-175.
Barzda, V., Istokovics, A., Simidjiev, I. and Garab G. (1996) Structural flexibility of chiral macroaggregates of light-harvesting chlorophyll a/b pigment-protein complexes. Light-induced reversible structural changes associated with energy dissipation, Biochemistry, 35(27):8981-8985.
Barzda, V., Garab, G., Gulbinas, V. and Valkunas, L. (1996) Evidence for long-range excitation energy migration in macroaggregates of the chlorophyll a/b light-harvesting antenna complexes, Biochim. Biophys. Acta, 1273(3):231-236.
Barzda, V., Mustardy, L. and Garab G. (1994) Size dependency of circular dichroism in macroaggregates of photosynthetic pigment-protein complexes, Biochemistry, 33(35):10837-10841.
Osvath, S., Meszena, G., Barzda, V. and Garab, G. (1994) Trapping magnetically oriented chloroplast thylakoid membranes in gels for electric measurements. J. Photochem.Photobiol., 26(3):287-292.