BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Examples\, Molecules\, and Methods for Super-Resolution Imaging in
  Cells with Single Molecules - Professor W. E. Moerner\, Department of Che
 mistry\, Stanford University\, Stanford\, California
DTSTART:20110629T160000Z
DTEND:20110629T170000Z
UID:TALK31779@talks.cam.ac.uk
CONTACT:David Klenerman
DESCRIPTION:Since the first optical detection and spectroscopy of a single
  molecule in a condensed phase material1\, much has been learned about the
  ability of single molecules to probe local nanoenvironments and individua
 l behavior in biological and nonbiological materials in the absence of ens
 emble averaging that can obscure heterogeneity.  Because each single fluor
 ophore acts a light source roughly 1 nm in size\, microscopic imaging of i
 ndividual fluorophores leads naturally to superlocalization\, or determina
 tion of the position of the molecule with precision beyond the optical dif
 fraction limit\, simply by digitization of the point-spread function from 
 the single emitter.  For example\, the shape of single filaments in a livi
 ng cell can be extracted simply by allowing a single molecule to move thro
 ugh the filament2. The addition of photoinduced control of single-molecule
  emission allows imaging beyond the diffraction limit (super-resolution) a
 nd a new array of acronyms (PALM\, STORM\, F-PALM etc.) and advances have 
 appeared\, but a mechanism-independent term for these methods is Single-Mo
 lecule Active Control Microscopy (SMACM).  In terms of applications of thi
 s method\, we have used the native blinking and switching of a common yell
 ow-emitting variant of green fluorescent protein (EYFP) reported more than
  a decade ago3 to achieve sub-40 nm super-resolution imaging of several pr
 otein structures in the bacterium Caulobacter crescentus: the quasi-helix 
 of the actin-like protein MreB4\, the cellular distribution of the DNA bin
 ding protein HU5\, and the recently discovered division spindle composed o
 f  ParA filaments6.  Even with these advances\, better emitters would prov
 ide more photons and improved resolution\, and a new photoactivatable smal
 l-molecule emitter has recently been synthesized and targeted to specific 
 structures in living cells to provide super-resolution images7. Finally\, 
 a new optical method for extracting three-dimensional position information
  based on a double-helix point spread function enables quantitative tracki
 ng of single mRNA particles in living yeast cells with 15 ms time resoluti
 on and 25-50 nm spatial precision8.  These examples illustrate the power o
 f single-molecule super-resolution optical imaging in extracting new struc
 tural and functional information in living cells.\n\n\n[1] W. E. Moerner a
 nd L. Kador\, \, “Optical Detection and Spectroscopy of Single Molecules
  in Solids\,” Phys. Rev. Lett. 62\, 2535 (1989).\n[2] S. Y. Kim\, Z. Git
 ai\, A. Kinkhabwala\, L. Shapiro\, and W. E. Moerner\, “Single Molecules
  of the Bacterial Actin MreB Undergo Directed Treadmilling Motion in Caulo
 bacter crescentus\,” Proc. Nat. Acad. Sci. (USA) 103\, 10929-10934 (2006
 ).\n[3] R. M. Dickson\, A. B. Cubitt\, R. Y. Tsien\, and W. E. Moerner\, 
 “On/Off Blinking and Switching Behavior of Single Green Fluorescent Prot
 ein Molecules\,” Nature 388\, 355 (1997).\n[4] J. S. Biteen\, M. A. Thom
 pson\, N. Tselentis\, G. R. Bowman\, L. Shapiro\, and W. E. Moerner\, “S
 uperresolution Imaging in Live Caulobacter Crescentus Cells Using Photoswi
 tchable EYFP\,” Nature Meth. 5\, 947-949 (2008).\n[5] Steven F. Lee\, Mi
 chael A. Thompson\, Monica Schwartz\, Lucy Shapiro\, and W. E. Moerner\, 
 “Super-Resolution Imaging of the Nucleoid-Associated Protein HU in Caulo
 bacter crescentus\,” Biophys. J. Lett. (appearing April 2011).\n[6] Jero
 d L. Ptacin\, Steven F. Lee\, Ethan C. Garner\, Esteban Toro\, Michael Eck
 art\, Luis R. Comolli\, W.E. Moerner\, and Lucy Shapiro\, “A spindle-lik
 e apparatus guides bacterial chromosome segregation\,” Nature Cell Biolo
 gy 12\, 791-798 (2010).\n[7] Hsiao-lu D. Lee\, Samuel J. Lord\, Shigeki Iw
 anaga\, Ke Zhan\, Hexin Xie\, Jarrod C. Williams\, Hui Wang\, Grant R. Bow
 man\, Erin D. Goley\, Lucy Shapiro\, Robert J. Twieg\, Jianghong Rao\, and
  W. E. Moerner\, “Superresolution Imaging of Targeted Proteins in Fixed 
 and Living Cells Using Photoactivatable Organic Fluorophores\,” J. Am. C
 hem. Soc. 132\, 15099-15101 (2010).\n[8] Michael A. Thompson\, Jason M. Ca
 solari\, Majid Badieirostami\, Patrick O. Brown\, and W.E. Moerner\, “Th
 ree-dimensional tracking of single mRNA particles in S. cerevisiae using a
  Double-Helix Point Spread Function\,” Proc. Nat. Acad. Sci. (USA) 107\,
  17864-17871 (2010).\n\n
LOCATION:Pfizer Lecture Theatre\, Department of Chemistry\, Lensfield Rd\,
  CB2 1EW
END:VEVENT
END:VCALENDAR