Further studies on the effects of stress in the adult on the eggs of Mytilus edulis

Stereological principles provide efficient and reliable tools for the determination of quantitative parameters of tissue structure on sections. Some principles which allow the estimation of volumetric ratios, surface areas, surface-to-volume ratios, thicknesses of tissue or cell sheets, and the number of structures are reviewed and presented in general form; means for their practical application in electron microscopy are outlined. The systematic and statistical errors involved in such measurements are discussed.

Latent beta-glucuronidase and glucosaminidase activities have been demonstrated in small cytoplasmic particles, which may possibly be primary lysosomes, as well as some larger granules of the digestive cells of the common mussel. Latency was indicated by increased staining of these structures following incubation in buffer at pH 4.5 at 37 degrees C. The exposure of mussels to temperatures of 25-28 degrees C over a period of four days induced a significant decrease in the latency of lysosomal glucosaminidase. Thermal death produced labilization of lysosomes although selective release of hydrolase activity was indicated by the differential latency of glucosaminidase and glucuronidase. The injection of hydrocortisone induced a significant increase in latency in stressed animals, indicating that the stress response involved changes in structure and function of membranes.