Robust colony recognition for high-throughput growth analysis from suboptimal low-magnification brightfield micrographs

New technological advances have enabled high-throughput phenotyping at the single-cell level. However, analyzing the large amount of data automatically and accurately is a great challenge. Currently available software achieves cell and colony tracking through the use of either manual curation of images, which is time consuming, or high-resolution images requiring specialized microscopy setups or fluorescence, which limits applicability and results in greatly decreased experimental throughput. Here we introduce a new algorithm, Processing Images Easily (PIE), that automatically tracks colonies of the yeast Saccharomyces cerevisiae in low-magnification brightfield images by combining adaptive object-center detection with gradient-based object-outline detection. We tested the performance of PIE on low-magnification brightfield time-lapse images. PIE recognizes colony outlines very robustly and accurately across a wide range of image brightnesses and focal depths. We show that PIE allows for unbiased and precise measurement of growth rates in a large number (>90,000) of microcolonies in a single time-lapse experiment.

Dissecting ant recognition systems in the age of genomics

Hamilton is probably best known for his seminal work demonstrating the role of kin selection in social evolution. His work made it clear that, for individuals to direct their altruistic behaviours towards appropriate recipients (kin), mechanisms must exist for kin recognition. In the social insects, colonies are typically comprised of kin, and colony recognition cues are used as proxies for kinship cues. Recent years have brought rapid advances in our understanding of the genetic and molecular mechanisms that are used for this process. Here, I review some of the most notable advances, particularly the contributions from recent ant genome sequences and molecular biology.