Fluorescence Dynamics in the Endoplasmic Reticulum of a Live Cell: Time‐Resolved Confocal Microscopy. Issue 18 (14th July 2016)

• Record Type: Journal Article
• Authors: Ghosh, Shirsendu; Nandi, Somen; Ghosh, Catherine; Bhattacharyya, Kankan
• Is Part Of: Chemphyschem. Volume 17:Issue 18(2016)
• Page Start: 2818
• Page End: 2823
• Publication Date: 2016-07-14
• Subjects: confocal microscopy -- endoplasmic reticulum -- fluorescence oscillation -- lung cells -- solvent relaxation; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201600425
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: Fluorescence dynamics in the endoplasmic reticulum (ER) of a live non‐cancer lung cell (WI38) and a lung cancer cell (A549) are studied by using time‐resolved confocal microscopy. To selectively study the organelle, ER, we have used an ER‐Tracker dye. From the emission maximum ( λ max em ) of the ER‐Tracker dye, polarity (i.e. dielectric constant, ϵ ) in the ER region of the cells (≈500 nm in WI38 and ≈510 nm in A549) is estimated to be similar to that of chloroform ( λ max em =506 nm, ϵ ≈5). The red shift by 10 nm in λ max em in the cancer cell (A549) suggests a slightly higher polarity compared to the non‐cancer cell (WI38). The fluorescence intensity of the ER‐Tracker dye exhibits prolonged intermittent oscillations on a timescale of 2–6 seconds for the cancer cell (A549). For the non‐cancer cell (WI38), such fluorescence oscillations are much less prominent. The marked fluorescence intensity oscillations in the cancer cell are attributed to enhanced calcium oscillations. The average solvent relaxation time (< τ s >) of the ER region in the lung cancer cell (A549, 250±50 ps) is about four times faster than that in the non‐cancer cell (WI38, 1000±50 ps). Abstract : Fluorescence oscillation alive : The endoplasmic reticulum (ER)‐Tracker dye inside the non‐cancer lung cell (WI38) exhibits almost no prominent oscillation in the fluorescence intensity and a slow dynamics in solvent relaxation. On the other hand, it displays prominent oscillations in fluorescence intensity and a faster solvent relaxation time inside the ER region of the lung cancer cell (A549).