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The Prompt Detection of Ionizing Radiations by a Marine Coelenterate

Donald J. Kimeldorf and Rosanne W. Fortner
Radiation Research
Vol. 46, No. 1 (Apr., 1971), pp. 52-63
DOI: 10.2307/3573101
Stable URL: http://www.jstor.org/stable/3573101
Page Count: 12
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The Prompt Detection of Ionizing Radiations by a Marine Coelenterate
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Abstract

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.

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