Yeast Biomechanics

Over million years of evolution, micron-scale structures (capsules) of different shapes (e.g. beanshaped, saturnoid, needle-shaped, hat-shaped, etc.) and nano-scale surface ornamentations (e.g. hairy, warty, hooked ridges, etc.) were optimized in yeasts for effective water driven smart movement [

1

],[

2

]. Until now the function of these shapes and ornamentations has been speculative [

2

]. Using immunofluorescence, electron and confocal laser scanning microscopy, physical mechanisms in yeasts are exposed preventing capsules becoming tightly packed (“stuck”) within micron-scale bottleshaped containers (birth sacs) thereby blocking their water driven forced release through narrow birth sac openings. In some cases oxylipin lubricated nano-scale gear-like structures, orientated across the surfaces of bean-shaped capsules, are used to affect unhindered release. In other cases gear-like structures are replaced by lubricated compressible slimy sheaths to affect the same [

3

]. We also found nano-scale ornamentations on capsule surfaces affecting boomerang spore movement and eventual birth sac rupture through the penetration of turgor-directed spiky ends into birth sac cell walls [

4

]. This interpretation of the mechanics involved might find application in nano-, aero- and hydrotechnologies with the re-scaling of these structures.