Biology subjects

Opstad, I. S.

Publications and source records attributed to Opstad, I. S..

3 recordsLinked to original sources

bioRxiv2023

LysoTracker Deep Red exhibits photoconversion in multi-color structured illumination microscopy

In new chemical environments or for untested combinations of illumination, unexpected changes to the fluorescent labels photophysical properties, such as photoconversion, can occur. This letter reports on photoblueing of a common cellular probe, LysoTracker Deep Red, in multi-color super-resolution structured illumination microscopy. The dye was found to exhibit a blue shift of its fluorescence spectrum as a step on the photobleaching pathway during such imaging. The observed photoblueing (emission spectrum shifted to lower wavelengths) of this probe is an important finding as many cellular assays rely on the spectral separation of this and such fluorescent cellular markers. No spectral shift of LysoTracker Deep Red was observed for longterm imaging using diffraction limited microscopy requiring significantly lower light dose. We expect that the knowledge of occurrence of photoconversion during super-resolved imaging using this popular dye will help researchers design better imaging experiments and avoid potentially erroneous interpretations in multi-color microscopy.

biophysics↗

bioRxiv2022

The complexity of keratocyte migration in salmon explant cultures: initial results and future prospects

Intact skin is of uttermost importance for fish welfare. The fish skin provides an environmental barrier and protects against invading pathogens. However, both pathogens and physical insults cause skin wounds that are of major concern in modern fish farming. The behavior and interactions between keratocyte cells and sheets of cells are not well understood. The collective migration of keratocytes (skin epithelial cells) is of central importance for wound healing in fish. In this study, we aimed to elucidate the complex wound healing process in fish skin by studying in vitro cultures of these highly motile cells. Using explant cultures from farmed Atlantic salmon (Salmo salar) and differential interference contrast microscopy (DIC), we have captured the dynamics of sheets of cells from harvested fish scales and of individual cells interacting in the cell sheet vicinity. In addition to direct contact, the cells were observed to interact through long membrane tubes, turn, rotate, merge, and/or detach. Additionally, stationary cells and cells moving on top of the cell sheets were observed. Cell sheets approaching one another from different scales did not merge but dispersed.

cell biology↗

bioRxiv2019

A waveguide imaging platform for live-cell TIRF imaging of neurons over large fields of view

Large fields of view (FOVs) in total internal reflection fluorescence microscopy (TIRFM) via waveguides have been shown to be highly beneficial for single molecule localisation microscopy on fixed cells [1, 2] and have also been demonstrated for short-term live-imaging of robust cell types [3-5], but not yet for delicate primary neurons nor over extended periods of time. Here, we present a waveguide-based TIRFM set-up for live-cell imaging of demanding samples. Using the developed microscope, referred to as the ChipScope, we demonstrate successful culturing and imaging of fibroblasts, primary rat hippocampal neurons and axons of Xenopus retinal ganglion cells (RGC). The high contrast and gentle illumination mode provided by TIRFM coupled with the exceptionally large excitation areas and superior illumination homogeneity offered by photonic waveguides have potential for a wide application span in neuroscience applications.

neuroscience↗