Imaging and Fluorescence Quantification in Caenorhabditis eleganswith Flow Vermimetry and Automated Microscopy

Gene activation and cellular biomarkers are commonly monitored using fluorescent signals from transgenic reporters or dyes. These quantifiable markers are critical for biological research and serve as an incredibly powerful tool, even more so when combined with high-throughput screening. Caenorhabditis elegans is a particularly useful model in this regard, as it is inexpensive to grow in vast numbers, has a rapid generation time, is optically transparent, and can readily fit within 384-well plates. However, fluorescence quantification in worms is often cumbersome. Quantification is frequently performed using laborious, low-throughput, bias-prone methods that measure fluorescence in a comparatively small number of individual worms. Here we describe two methods, flow vermimetry using a COPAS BioSorter and an automated imaging platform and analysis pipeline using a Cytation5 multimode plate reader and image analysis software, that enable high-throughput, high-content screening in C. elegans. Flow vermimetry provides a better signal-to-noise ratio with fewer processing steps, while the Cytation5 provides a convenient platform to image samples across time. Fluorescence values from the two methods show strong correlation. Either method can be easily extended to include other parameters, such as the measurement of various metabolites, worm viability, and other aspects of cell physiology. This broadens the utility of the system and allows it to be used for a wide range of molecular biological purposes.