Biology subjects

Copeland, D. S.

Publications and source records attributed to Copeland, D. S..

2 recordsLinked to original sources

bioRxiv2023

A fluorescence viewer for rapid molecular assay readout in space and low-resource terrestrial environments

Fluorescence-based assays provide sensitive and adaptable methods for point of care testing, environmental monitoring, studies of protein abundance and activity, and a wide variety of additional applications. Currently, their utility in remote and low-resource environments is limited by the need for technically complicated or expensive instruments to read out fluorescence signal. Here we describe the Genes in Space Fluorescence Viewer (GiS Viewer), a portable, durable viewer for rapid molecular assay readout that can be used to visualize fluorescence in the red and green ranges. The GiS Viewer can be used to visualize any assay run in standard PCR tubes and contains a heating element. Results are visible by eye or can be imaged with a smartphone or tablet for downstream quantification. We demonstrate the capabilities of the GiS Viewer using two case studies - detection of SARS-CoV-2 RNA using RT-LAMP and quantification of drug-induced changes in gene expression via qRT-PCR on Earth and aboard the International Space Station. We show that the GiS Viewer provides a reliable method to visualize fluorescence in space without the need to return samples to Earth and can further be used to assess the results of RT-LAMP and qRT-PCR assays on Earth.

molecular biology↗

bioRxiv2022

Tonic GluD1 channel current is independent of G protein activity in the dorsal raphe nucleus

AO_SCPLOWBSTRACTC_SCPLOWPreviously, using electrophysiological recordings from adult male and female mouse brain slices containing the dorsal raphe nucleus, we showed that GluD1R channels carry ionic current and are modulated via activation of Gq-coupled 1-adrenergic receptors (1-AR) in a GTP-dependent manner (Gantz et al., 2020). GluD1R channels also carry a tonic cation current, generally ~-20 pA at subthreshold membrane potentials (Gantz et al., 2020). The origin of tonic GluD1R channel current is unknown. Here, using the same preparation, we show there is no role of on-going G protein-coupled receptor activity in generating or sustaining tonic GluD1R channel current. Neither augmentation nor disruption of G protein activity had an effect on tonic GluD1R current. These results reveal that tonic GluD1R current arises from a mechanism separate from on-going activity of G protein-coupled receptors. Under current clamp, block of GluD1R channels hyperpolarized the membrane by ~10 mV at subthreshold potentials leading to reduced excitability. Thus, GluD1R channels carry a G protein-independent tonic current that contributes to subthreshold drive of action potential firing in the dorsal raphe nucleus.

neuroscience↗