AGE-DEPENDENT EXPRESSION OF PROTEINS IN THE CLADOCERAN DAPHNIA-MAGNA UNDER NORMAL AND HEAT-STRESS CONDITIONS

1. Newly synthesized proteins and total protein synthesis were examine d in eight different age-groups in the cladoceran Daphnia magna, under normal and heat-stressed conditions. 2. Protein expression varied wit h the age of the animal as well as in response to heat-shock. 3. Heat- shock does not induce the same heat-shock proteins (HSP) in all age gr oups. 4. Some of the HSP are present constitutively and are upregulate d in heat stress. 5. If HSP confer protection to the organism, there m ay be unwanted variation in tolerance to environmental stressors in or ganisms used in bioassays.