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AssayWise Letters 2019, Vol. 8(2)

Featured Article

A Simple End-Point Calcium Assay Using a Green Fluorescent Indicator Fluo-8E™, AM
The intracellular release of calcium from internal stores upon GPCR stimulation is transient. To study this transient calcium signaling in a microplate format, a fluorescence plate reader that has a built-in liquid handling system and kinetic reading capability is often required. This limits the usage of the conventional fluorescence plate readers to conduct studies on calcium signaling. We report the development of an endpoint calcium assay that can be used to monitor the effects of GPCR modulators in calcium response cell-based assays with conventional fluorescence microplate readers using bottom reading mode. Fluo-8H™ AM, a cell permeant, non-fluorescent calcium indicator that has enhanced and long-lived fluorescence upon calcium binding was used in this assay. We demonstrated the capability of this assay to accurately determine the EC50 of numbers of GPCR modulators. The results are comparable to the results from assays utilizing the widely used fluorescent calcium indicators Fluo-4 AM and Fluo-3 AM in kinetic assays....

NAD+ Integration in Cellular Pathways
Cellular metabolism is the beginning of all other activities in living cells, providing energy for the millions of biochemical reactions that take place in any given moment. As such, any dysfunction in this process has immediate effects both on an intracellular scale and for overall human health. One of the most heavily studied aspects of this dysfunction is the changing levels and ratios of NAD+ and its related forms, enzymatic cofactors and byproducts....

Power Styramide™ Signal Amplification a Superior Alternative to Tyramide Signal Amplification
Similar to tyramide signal amplification, Power Styramide™ Signal Amplification (PSA™) utilizes the catalytic activity of horseradish peroxidase (HRP) for the covalent deposition of iFluor™ dye labeled-Styramide™ radicals onto a target protein or nucleic acid sequence in situ. By combining the superior brightness and photostability of our iFluor™ dyes, PSA™ imaging generates fluorescence signals with significantly higher precision and clarity needed for high-resolution imaging of low-abundance targets in cells and tissues....

Fluorescent Detection of Cell Senescence For Flow Cytometry and Imaging Applications
Cellular Senescence is an irreversible growth arrest triggered to prevent DNA damaged cells from dividing. During cellular senescence, senescence-associated beta-galactosidase (SA-beta-gal) activity becomes highly over-expressed, making it a suitable biomarker for identifying senescent cells. To facilitate detection we have developed a sensitive cell-permeable substrate that can be used for the fluorescent detection of senescent cells in both flow cytometry and imaging applications....