Symposium on radiation effects on cells and bacteria.

Radiobiology is an exciting field today. Old most notable examples are the reactions undertheories are found inadequate; new ones push lying the oxygen effect in ionizing radiations, forwad.forrecog o. Of apsh as described by Stapleton in this symposium. ci linesoradiobiologynition. of the crosdis(d) A large number of chemicals have been disp r covered which have effects similar to radiation. At a meeting for radiobiology, there mingle phyNo longer are radiations the sole inducers of sicians, embryologists, physiologists, biophysimutation. In addition, exact knowledge of an cists, biochemists, physical chemists, geneticists, almost bewildering variety of end effects of radia-. bacteriologists, and virologists. All must learn tions has accumulated. To name only a few: each other's language. The researcher continulethality, gene mutation, chromosomal aberraally meets viewpoints from outside his own spetions, and various types of growth inhibition. cialty. And ever present is the feeling that the Then there are such less understood but signifisolution of the problems of radiobiology may cant effects as the induction of lysogenesis in be a life and death matter for the human race, bacteria. threatened with disaster from the increasing What is the relation between radiations and radiation of the atomic age. radiomimetic chemicals? What is the link beAmong the recent developments which have tween all the end effects? The scientist can atbrought radiobiology to its present interesting, tack such an apparently indigestible mass of if somewhat confused, state are: (a) The target data in two ways. He can look for all possible theory, which for many years dominated thinkdifferences between various types of radiations ing in this science, has proven unsatisfactory. and their effects and try to organize the data in It simply does not explain enough. But no equally this fashion. Or he can seek some common deunifying theory has yet risen to replace the target theory, which still remains the most useful nominatond unif thedmate so me single concept we have. (b) Radiation effects geras areesoundhand serve as a check upon each other. have proven to be reversible (or preventable) Perhaps a way to simplify the discussion is to to a degree not previously suspected. In addition consider the one feature characteristic of almost to photoreactivation, there are also heat, cataall radiation effects-the delay between the lase, and nutritional reactivations. Others are initial inciting agent, and the first appearance likely to be discovered. (c) The indirect action of an end effect, be it mutation or death of the