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The Prompt Detection of Ionizing Radiations by a Marine Coelenterate
Donald J. Kimeldorf and Rosanne W. Fortner
Vol. 46, No. 1 (Apr., 1971), pp. 52-63
Published by: Radiation Research Society
Stable URL: http://www.jstor.org/stable/3573101
Page Count: 12
You can always find the topics here!Topics: Ionizing radiation, Sea water, Radiation dosage, Invertebrates, Nervous system, Mesentery, Photoreceptors, Nerve net, Specimens, Irradiation
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The sea anemone, Anthopleura xanthogrammica, has been the subject of a study regarding the detection of ionizing radiations by an organism with a relatively elementary nervous system. The results indicated that the anemone can detect x-rays and will withdraw its tentacles with an exposure to 20 R or more. Reaction time varied inversely with exposure rate, ranging from 102 seconds at 20 R/sec to 266 seconds at 1 R/sec. Reaction time was not affected by exposure duration at a given exposure rate once a threshold amount had been exceeded. Tentacle withdrawal was followed at higher exposures by a sequence of oral disc and column reactions leading to complete closure of the oral disc. Both local reactions and reactions outside the field of exposure could be demonstrated. On the basis of related experiments and the present study, it appears likely that ionizing radiations may activate an unknown photoreceptor mechanism and/or act directly on the neuromuscular processes to initiate the behavioral response. It is apparent that a highly specialized neural system is not essential for the detection of ionizing radiations.
Radiation Research © 1971 Radiation Research Society