9319634 Pickard Living organism possess internal biological clocks that control the timing of many different biological processes. Jet lag, ability to concentrate, the way you respond to anesthesia are all affected by daily or seasonal biological cycles. Organisms isolated without exposure to day:night cycles or other environmental time cues continue to express rhythmic processes but with a period only approximating 24 hours. One striking day/night rhythmicity is the synthesis and secretion of the hormone melatonin by the pineal gland. While it is clear that the pineal gland plays a major role in the control of circadian activity rhythms, a major question is whether single isolated cells also exhibit these 24 hour circadian oscillations. Dr. Pickard is establishing the technology to accurately detect rhythmic fluctuations in hormone secretion from single cells. Using an in vitro preparation of dissociated pineal cells in short-term culture, he is developing a reverse hemolytic plaque assay to measure melatonin secretion in single isolated cells. This technology will enable Dr. Pickard to detect rhythmic hormone secretion in the attamol range (10-18mol). With this level of sensitivity, he will establish the procedures to sequentially assay melatonin secretion from the same isolated cells, thus providing an answer to one of the major fundamental questions regarding the organization of biological clocks. ***
