Published online by Cambridge University Press: 06 April 2009
The cuticular permeability of anhydrobiotic 4th-stage juveniles of Ditylenchus dipsaci decreases during rehydration, as indicated by staining with osmium tetroxide, the measurement of permeability coefficients by the rate of uptake of tritiated water from a HOH/C-inulin bathing solution and by an increased ability to slow down the rate of water loss and to survive subsequent desiccation. The initial decrease in permeability coefficient is rapid, suggesting a physical effect due to the rehydration of the cuticle, followed by a slower reduction over the subsequent 1–4 h which is dependent upon metabolic activity. The reestablishment of the permeability barrier is sensitive to metabolic inhibitors which affect enzyme activity and post-transcriptional protein synthesis. Sodium iodoacetamide was the only inhibitor which affected maintenance of the permeability barrier. An Arrhenius plot of changes in cuticular permeability with temperature indicated a sharp increase in permeability at 40–50°C and brief exposure to diethyl ether resulted in loss of the permeability barrier, suggesting that a superficial layer, probably the epicuticle, is responsible for controlling cuticular permeability.
Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
Department of Microbiology, University College, Newport Rd, Cardiff CF2 1TA, UK.