Quantitative assay for evaluating anti‐clumping reagents

Abstract

A model system was developed to quantitatively identify reagents that unclump cells (yeast, Saccharomyces cerevisiae). Biofilms, infections and cancer cells in the circulation often involve a clumped or adhering state. Reagents that unclump cells might help lead to the development of anti‐biofilm, anti‐infection and anti‐cancer cell survival drugs. Various sugars and an amino acid (0 mg/ml – 20 mg/ml) were tested for their ability to unclump low pH (2.4), flocculated, formaldehyde (1%) fixed yeast in distilled water. The yeast with and without the reagents were stirred in 0.5 ml droplets on glass microscope slides in distilled water and percentages of single yeast cells (vs clumped yeast) were recorded over a 60 min time course by focusing on the edge of the droplets in 923 total trials. Alpha methyl glucose, alpha methyl mannose and D‐glucose increased the percentage of single cells over controls in the absence of reagents (p less than 0.05), while L‐arginine did not and D‐fucose, alpha lactose and sucrose had inconsistent effects. Most important in this study was the development of an essentially no‐cost, remarkably simple assay, to quantitatively assess reagents that could clump or unclump cells (supported by NSF Presidential Award 0731633, NIH NIGMS SCORE S0648680, RISE, MARC, Joseph Drown Foundation, Sidney Stern Memorial Trust).