A simple colony‐formation assay in liquid medium, termed ‘tadpoling’, provides a sensitive measure of Saccharomyces cerevisiae culture viability

Abstract

Here we describe the first high-throughput amenable method of quantifying Saccharomyces cerevisiae culture viability. Current high-throughput methods of assessing yeast cell viability, such as flow cytometry and SGA analysis, do not measure the percentage viability of a culture but instead measure cell vitality or colony fitness, respectively. We developed a method, called tadpoling, to quantify the percentage viability of a yeast culture, with the ability to detect as few as one viable cell amongst~10 8 dead cells. The most important feature of this assay is the exploitation of yeast colony formation in liquid medium. Utilizing a microtiter dish, we are able to observe a range of viability of 100% to 0.0001%. Comparison of tadpoling to the traditional plating method to measure yeast culture viability reveals that, for the majority of Saccharomyces species analyzed there is no significant difference between the two methods. In comparison to flow cytometry using propidium iodide, the high-throughput method of measuring yeast culture viability, tadpoling is much more accurate at culture viabilities < 1%. Thus, we show that tadpoling provides an easy, inexpensive, space-saving method, amenable to high-throughput screens, for accurately measuring yeast cell viability.

An Energy-Independent Pro-longevity Function of Triacylglycerol in Yeast

“…The number of colonies multiplied by the dilution factor of that spot was regarded as the viability. This method was adapted from the Tadpole assay as described in [ 91 ].…”

Directed Evolution of Saccharomyces cerevisiae for Increased Selenium Accumulation

“…To examine additionally if phosphate-limitation affects selenite resistance, a liquid colony-forming assay, termed tadpoling, was employed [ 11 ]. In this assay, cells are serially-diluted in liquid medium in a 96-well plate that is kept stationary until colonies form, which are then quantified to determine a culture viability.…”

The enigmatic role of fungal annexins: the case of Cryptococcus neoformans

“…C. neoformans , opsonized with 10 µg/ml of mAb 18B7 (54) were added at a Multiplicity of Infection (MOI) indicated in the figure legend in a final volume of 250 µl and infection proceeded for 24h. Macrophages were lysed by resuspending all cells with 10x the volume of distilled water and number of surviving yeasts was measured via a “tadpole” assay (55). Briefly, the aqueous suspension of yeast cells and lysed macrophages is serially 10-fold diluted in YPD broth and allowed to grown overnight at 30°C.…”