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Seminars 2010

Tuesday, December 14
Sebastian Sorgenfrei, Shepard Lab
Department of Electrical Engineering
"Probing single-molecule DNA hybridization kinetics with a carbon nantotube"

Tuesday, November 30
Linda Yu, Tong Lab
Department of Biological Sciences
"Structural and Functional Studies of Staphylococcus aureus Pyruvate Carboxylase"

Friday, November 19
Morgan Huse, Ph. D.
Sloan-Kettering Institute
Weill-Cornell Graduate School of Medical Sciences

"Photochemical approaches to lymphocyte signaling"

Abstract
Lymphocytes such as T cells, B cells, and natural killer (NK) cells can completely transform their cellular architecture within minutes in response to stimulation through cell surface receptors. This property makes them quite intriguing as cell biological systems, but it also makes them difficult to study without tools that facilitate the observation of dynamic responses in tightly controlled environments. To address this issue, we have developed photoactivatable reagents that enable us to trigger specific cell surface receptors with a pulse of ultraviolet light. Using these reagents in single cell imaging experiments, we can stimulate submicron-sized regions of the plasma membrane and monitor downstream intracellular responses with excellent spatiotemporal resolution. To date, we have used this approach to explore the signaling pathways that drive cytoskeletal polarization in T cells, and also to characterize the molecular mechanisms of inhibitory receptor signaling in NK cells. The further application of photochemical tools in this way has the potential to make lymphocyte cell biology substantially more amenable to mechanistic analysis.

Tuesday, November 9
Yunqing Lin, Snyder Lab
Department of Chemistry
"Total Syntheses of Resveratrol-based Natural Products"

Friday, September 24
Prof Alvin T. Yeh
Dept of Biomedical Engineering, Texas A&M University
"Microscopy meets mechanobiology: multifunctional imaging with ultrashort optical pulses"

Abstract
Advances in nonlinear and multimodal microscopy utilizing properties of sub-10-femtosecond pulses will be discussed as well as its applications in live cell studies of tissue biomechanical responses and of complex molecular and cellular processes in vertebrate development. Recent results will be presented in the development of integrated nonlinear and optical coherence microscopy utilizing the ultrashort coherence length of sub-10-fs pulses for characterizing depth dependent microstructural and mechanical responses of the cornea and in the combination of spectrally broad two-photon excitation with multispectral detection for multimolecular and cellular imaging of zebrafish embryogenesis. These results highlight our interests in the development of optical microscopy based on ultrashort optical pulses to study complex biological systems.

Tuesday, September 21
Prof Melissa Moore
Depts of Biochemistry and Molecular Pharmacology
"Into the CoSMoS: The Dynamics of Spliceosome Assembly One Molecule at a Time"

Friday, July 23
Martin B. van der Mark
Philips Research Europe, The Netherlands
"An efficient way to do spectroscopic diffuse optical imaging"

Abstract
The ultrastructure of cells and tissues ranges over 3 orders of magnitude, from membranes (~10 nm) to organelles to cells (~10 mm). The size distribution presented by this ultrastructure follows a simple power law behavior: probability(d) = A d-b where d = diameter of structure and b ≈ 1. Various investigators have contributed to understanding how b varies during pathology. Optically, such a size distribution yields a similar wavelength behavior of light scattering by the ultrastructure: reduced scattering coeff. ms’ = a l-b using the same factor b. Therefore, optical measurements of light scattering specify b, which gives an indication of the size distribution of ultrastructure in the cells or tissue. This seminar gives an overview of the connection between optical scattering behavior and ultrastructure, and discusses some current experimental approaches toward imaging pathology using scattering as a contrast mechanism.

Tuesday, May 25
Xiaoyin Chen, Chalfie Laboratory
Department of Biological Sciences
"Integrin Signaling is Required for Mechanosensation in the Touch Receptor Neurons"

Friday, May 14
Prof Steven L. Jacques
Depts of Dermatology & Biomedical Engineering
Oregon Health & Science University
"How fractal is light scattering in biological tissues? ...toward label-free optical imaging of pathology"

Abstract
The ultrastructure of cells and tissues ranges over 3 orders of magnitude, from membranes (~10 nm) to organelles to cells (~10 mm). The size distribution presented by this ultrastructure follows a simple power law behavior: probability(d) = A d-b where d = diameter of structure and b ≈ 1. Various investigators have contributed to understanding how b varies during pathology. Optically, such a size distribution yields a similar wavelength behavior of light scattering by the ultrastructure: reduced scattering coeff. ms’ = a l-b using the same factor b. Therefore, optical measurements of light scattering specify b, which gives an indication of the size distribution of ultrastructure in the cells or tissue. This seminar gives an overview of the connection between optical scattering behavior and ultrastructure, and discusses some current experimental approaches toward imaging pathology using scattering as a contrast mechanism.

Tuesday, April 27
Brian Gillette, Sia Laboratory
Department of Biomedical Engineering
"Microfabrication and Dynamic Control of Natural Extracellular Matrices for Tissue Engineering"

Tuesday, March 30
Geza Szilvay, Banta Laboratory
Department of Chemical Engineering
“The Beta Roll Domain as a Novel Allosterically-Regulated Scaffold for Biomolecular Recognition”

Tuesday, March 2
Laura Wingler, Cornish Laboratory
Department of Chemistry
“Reiterative Recombination: A Straightforward and Efficient Strategy for the Large-Scale, In Vivo Assembly of DNA”