Rapidly Developing Yeast Microcolonies Differentiate in a Similar Way to Aging Giant Colonies

Libuše Váchová,Zdena Palková,Michaela Pokorná,Ladislava Hatáková,Michal Čáp

doi:10.1155/2013/102485

Abstract

During their development and aging on solid substrates, yeast giant colonies produce ammonia, which acts as a quorum sensing molecule. Ammonia production is connected with alkalization of the surrounding medium and with extensive reprogramming of cell metabolism. In addition, ammonia signaling is important for both horizontal (colony centre versus colony margin) and vertical (upper versus lower cell layers) colony differentiations. The centre of an aging differentiated giant colony is thus composed of two major cell subpopulations, the subpopulation of long-living, metabolically active and stress-resistant cells that form the upper layers of the colony and the subpopulation of stress-sensitive starving cells in the colony interior. Here, we show that microcolonies originating from one cell pass through similar developmental phases as giant colonies. Microcolony differentiation is linked to ammonia signaling, and cells similar to the upper and lower cells of aged giant colonies are formed even in relatively young microcolonies. A comparison of the properties of these cells revealed a number of features that are similar in microcolonies and giant colonies as well as a few that are only typical of chronologically aged giant colonies. These findings show that colony age per se is not crucial for colony differentiation.

Highlights

When developing on solid media or in nonshaken liquid environments, yeast cells can organize into structured and differentiated multicellular communities where individual cells gain specific properties and can fulfill specific roles
Microcolonies of BY4742 growing on GMA solid plates pass through the developmental phases characterized by changes in external pH and ammonia production [24, 26]
Microcolonies, pass through the first acidic, alkali and second acidic developmental phases (Figure 1(a)), where the alkali phase is accompanied by ammonia production

Summary

Introduction

When developing on solid media or in nonshaken liquid environments, yeast cells can organize into structured and differentiated multicellular communities where individual cells gain specific properties and can fulfill specific roles. For example, natural strains of Saccharomyces cerevisiae form structured biofilm colonies [15, 16] that to some extent resemble the colonies formed by pathogenic yeasts of the Candida or Cryptococcus species [7]. These structured colonies exhibit features (such as the presence of multidrug resistance transporters and an extracellular matrix) that are important for the formation, development, and survival of natural yeast biofilms [17]. The internal architecture of these structured colonies differs strikingly from the architecture of smooth colonies that are formed by laboratory strains of S. cerevisiae

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Conclusion