title: BioPhotonics workstation: a versatile setup for simultaneous optical manipulation, heat stress, and intracellular pH measurements of a live yeast cell.
abstract: In this study we have modified the BioPhotonics workstation (BWS), which allows for using long working distance objective for optical trapping, to include traditional epi-fluorescence microscopy, using the trapping objectives. We have also added temperature regulation of sample stage, allowing for fast temperature variations while trapping. Using this modified BWS setup, we investigated the internal pH (pH(i)) response and membrane integrity of an optically trapped Saccharomyces cerevisiae cell at 5 mW subject to increasing temperatures. The pH(i) of the cell is obtained from the emission of 5-(and-6)-carboxyfluorescein diacetate, succinimidyl ester, at 435 and 485 nm wavelengths, while the permeability is indicated by the fluorescence of propidium iodide. We present images mapping the pH(i) and permeability of the cell at different temperatures and with enough spatial resolution to localize these attributes within the cell. The combined capability of optical trapping, fluorescence microscopy and temperature regulation offers a versatile tool for biological research.
authors: Department of Food Science, University of Copenhagen, 1958 Frederiksberg C, Denmark.
authors: Thomas
authors: T
authors: Aabo
authors: Andrew Raphael
authors: AR
authors: Banás
authors: Jesper
authors: J
authors: Glückstad
authors: Henrik
authors: H
authors: Siegumfeldt
authors: Nils
authors: N
authors: Arneborg
mesh_terms: D002138:Calibration; D002470:Cell Survival; D018869:Heat-Shock Response; D006863:Hydrogen-Ion Concentration; D042541:Intracellular Space / Q000737:chemistry*; D055620:Optical Phenomena; D055095:Optics and Photonics / Q000295:instrumentation*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000502:physiology*; D013696:Temperature