Clocks, biological

Nitrate has been described as a biological time bomb . Those who enjoy their doom and gloom will be pleased to hear that there may be two such bombs, one with a physical clock and one with a biological clock. Both can be studied with the aid of computer models. 

Dunlap, J. C., and Hastings, J. W. (1981). The biological clock in Gonyaulax controls luciferase activity by regulating turnover. J. Biol. Chem. 256 10509-10518. 

Circadian rhythm 24-Hour cycles of behavior and physiology that are generated by endogenous biological clocks (pacemakers). 

A number of studies have investigated the potential of melatonin to alleviate the symptoms of jet lag. Melatonin has been found to be effective in 11 placebo-controlled studies in reducing the subjective symptoms of jet lag such as sleepiness and impaired alertness (Arendt 2005). The most severe health effects of jet lag occur following eastbound flights, since this requires a phase advancement of the biological clock. In a recent study, phase advancement after melatonin administration (using 3 mg doses just before bedtime) occurred in all 11... 

Ding, J. M., Chen, D., Weber, E. T. et al. (1994). Resetting the biological clock mediation of nocturnal circadian shifts by glutamate and NO. Science 266, 1713-17. 

Circadian Sieep Rhythm. Sleep can be conceptualized as a pair of cycles each regulated by a biological clock. The larger cycle is the rhythm of sleep and wakefulness that operates according to a 24 hour (circadian) biological clock. The sleep-wake cycle is not our only circadian rhythm. Body temperature and certain hormones fluctuate in accordance with this same biological rhythm. 

Horwitz, M., Benson, K. F., Person, R. E., Aprikyan, A. G., and Dale, D. C., Mutations in ELA2, encoding neutrophil elastase define a 21-day biological clock in cyclic haematopoiesis. Nat. 

Foster RG 1998 Shedding light on the biological clock. Neuron 20 829—832... 

Okamura H, Miyake S, Sumi Y et al 1999 Photic induction of mPer1 and mPerl in Cry-Ae cieuat mice lacking a biological clock. Science 286 2531-2534 Oshima N 2001 Direct reception of light by chromatophores of lower vertebrates. Pigment Cell Res 14 312-319... 

Yagita K, Tamanlnl F, van der Horst G, Okamura H 2001 Molecular mechanisms of the biological clock in cultured fibroblasts. Science 292 278-281 Yagita K, Tamanini F, Yasuda M, Hoeijmakers JHJ, van der Horst GTJ, Okamura H 2002 Nucleocytoplasmic shuttling and mCRY-dependent inhibition of ubiquitylation of the mPER2 clock protein. EMBO J 21 1301—1314... 

Yu Q, Jacquier AC, Citri Y, Hamblen M, Hall JC, Rosbash M 1987 Molecular mapping of point mutations in the period gene that stop or speed up biological clocks in Drosophila melanogaster. Proc Natl Acad Sci USA 84 784-788... 

Camacho F, Cilio M, Guo Y et al 2001 Human casein kinase Idelta phosphorylation of human circadian clock proteins period 1 and 2. FEES Lett 489 159-165 Delaunay F, Thisse C, Marchand O, Laudet V, Thisse B 2000 An inherited functional circadian clock in zebrafish embryos. Science 289 297-300 Dunlap J 1998 Circadian rhythms. An end in the beginning. Science 280 1548-1549 Ebisawa T, Uchiyama M, Kajimura N et al 2001 Association of structural polymorphisms in the human period3 gene with delayed sleep phase syndrome. EMBO Rep 2 342-346 Edery I, Zwiebel LJ, Dembinska ME, Rosbash M 1994 Temporal phosphorylation of the Drosophila period protein. Proc Natl Acad Sci USA 91 2260-2264 Ishida N, Kaneko M, AUada R 1999 Biological clocks. Proc Natl Acad Sci USA 96 8819-8820... 

Okamura H et al 1999 Photic induction of mPerl and mPer2 in cry-deficient mice lacking a biological clock. Science 286 2531—2534... 

When at your new destination, try to get outside during the day as much as possible—sunlight is an extremely powerful stimulant that resets the biological clock. Staying indoors can worsen jet lag. 

In addition, if you like to plan ahead and want to minimize the jet lag you might experience on an upcoming trip, melatonin can be used to start resetting your biological clock... 

Since Lisa was taking melatonin at a time when her body s own melatonin levels were low, the melatonin pills helped her sleep better during the day and kept her biological clock set for the night shift. 

Avoid exposure to bright lights (i.e., sun lamps) for one to three hours prior to bedtime, since this can throw off your body s biological clock. 

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