Membrane Permeability and the Loss of Germination Factor from Neurospora crassa at Low Water Activities

Abstract

Neurospora crassa conidia incubating in buffer at low water activities (a w ) release a germination-essential component as well as 260-nm absorbing and ninhydrin-positive materials, regardless of whether an electrolyte or non-electrolyte is used to reduce a w . Chloroform and antibiotics known to increase cell-membrane permeability have a similar effect. This suggests that membrane damage occurs in media of low a w and that an increase in permeability is responsible for the release of cellular components. The damage caused in media of low a w is nonlethal in most cases, and the conidia recover when transferred to nutrient medium.