Thermal Properties of the Collagen of Jellyfish (Aurelia Coerulea) and their Relation to its Thermal Behaviour

Abstract

It has been reported elsewhere (Rigby 1968a, 1968b) that for a number of poikilotherms sudden changes occur in physiological behaviour at temperatures which are the same as the melting temperature of their molecular collagen. A more general statement, which includes the above observations, is that the upper limit of the environmental temperature for an animal corresponds with the melting tempera. ture of its molecular collagen. A number of workers have contributed to this idea and details may be found in Rigby (1968a). It is not suggested that collagen is uniquely involved in these events, although this may be so. No doubt other body proteins are altered at the same time. The useful point is that collagen is one of the few easily prepared body proteins with a characteristic melting point, and as such can serve as an indicator in studies concerned with the temperature relation of poikilotherms. For example, animals, which can be adapted to reproduce at higher or lower temperatures than is usual for them, may produce a collagen which shows a parallel alteration in its melting temperature. Such an experiment would afford a test of the general assumption that the constitution and properties of a protein are determined only by genetic coding (see also Ruda1l1968).