. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 522 H. BURGESS UOWSK AND JOHN D. PALM MR with time. By combining these two observations, it can be seen that however the chronomutagenic changes are produced, they apparently do not require substantial incorporation of deuterium into organismic compounds. It seems quite likely that much of the effect may be brought about simply by deuteration of the interstitium and the aqueous protoplasm, which, among other things, would significantly alter diffusion rates. The sameness of the responses of single- and multicellular plants a
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 522 H. BURGESS UOWSK AND JOHN D. PALM MR with time. By combining these two observations, it can be seen that however the chronomutagenic changes are produced, they apparently do not require substantial incorporation of deuterium into organismic compounds. It seems quite likely that much of the effect may be brought about simply by deuteration of the interstitium and the aqueous protoplasm, which, among other things, would significantly alter diffusion rates. The sameness of the responses of single- and multicellular plants and animals to deuterium shows that alterations in specific organ systems, such as nervous or endocrine systems, or so-called "blood-clock barriers" (Richter, 1970), are secondary problems. Enright ( 1971 ) has demonstrated that D^.O decreases the output of several high frequency pacemaker systems, and since each is dependent on ion exchange, he sug- gests that D^O chronomutagenicity may be a result of altered ionic flux rates. This suggestion seems reasonable. In the study of biological rhythms, the only tangible entity with which we have to work so far is the rhythm itself; the existence of an underlying control mecha- nism is only deduced. To date, all attempts to locate and identify this clock have failed. In addition to the clock and the overt rhythm, a third, separate entity, a coupler, is also involved. The evidence for the coupler derives from a variety of indirect direct. FIGURE 3. A mechanical analogy representing two means of coupling between a clock and a driven process. Details are given in the text. experiments : a single example will suffice here. A rhythm can be inhibited for a few hours, and then, when the block is removed, the rhythm will commence again in exact phase with controls (Brown et a/., 1970). This clearly demonstrates that the clock is not an integral part of a rhythmic process per sc, but is coupled to it in some way, and it is via this co
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