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Lyophilized spore dispenser
A lyophilized spore dispenser is provided which produces a finely divided, monoparticulate cloud of bacterial spores. The spores are contained within a tightly sealed chamber, and a turbulator orifice connected to an air supply source provides a jet of air which stirs up the spores and causes the spores to be suspended in eddy currents within the chamber. This air jet also produces a positive pressure within the chamber which forces the spores out of an injection orifice
Summoning the wind: Hydrodynamic cooperation of forcibly ejected fungal spores
The forcibly launched spores of the crop pathogen \emph{Sclerotinia
sclerotiorum} must eject through many centimeters of nearly still air to reach
the flowers of the plants that the fungus infects. Because of their microscopic
size, individually ejected spores are quickly brought to rest by drag. In the
accompanying fluid dynamics video we show experimental and numerical
simulations that demonstrate how, by coordinating the nearly simultaneous
ejection of hundreds of thousands of spores,\emph{Sclerotinia} and other
species of apothecial fungus are able to sculpt a flow of air that carries
spores across the boundary layer and around intervening obstacles. Many spores
are sacrificed to create this flow of air. Although high speed imaging of spore
launch in a wild isolate of the dung fungus \emph{Ascobolus} shows that the
synchronization of spore ejections is self-organized, which could lead to
spores delaying their ejection to avoid being sacrificed, simulations and
asymptotic analysis show that, close the fruit body, ejected spores form a
sheet-like jet that advances across the fruit body as more spores are ejected.
By ejecting on the arrival of the sheet spores maximize \emph{both} their range
and their contribution to the cooperative wind.Comment: Submission to the DFD 2009 Gallery of Fluid Motio
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