Most organisms, from cyanobacteria to humans are equipped with circadian clocks. These endogenous and self-sustained pacemakers allow organisms to adapt their physiology and behavior to daily environmental variations, and to anticipate them. The circadian clock is synchronized by environmental cues (i.e. light and temperature fluctuations). The fruit fly, Drosophila melanogaster, is well establ...

Circadian rhythms are governed by endogenous oscillators (clocks) in a wide variety of organisms can be phase shifted (i.e., delayed or advanced) by brief exposure to light and changes in temperature. The present study was to determine the influence of single light pulse (~ 100 lux; 15 minutes) at four circadian time points (CT 00, CT 06, CT 12 and CT 18) in wild type (WT; Oregon R); and vestig...

There are three mechanisms that may contribute to the health, performance, and safety problems associated with night-shift work: (1) circadian misalignment between the internal circadian clock and activities such as work, sleep, and eating, (2) chronic, partial sleep deprivation, and (3) melatonin suppression by light at night. The typical countermeasures, such as caffeine, naps, and melatonin ...

BACKGROUND Cell proliferation in all rapidly renewing mammalian tissues follows a circadian rhythm that is often disrupted in advanced-stage tumors. Epidemiologic studies have revealed a clear link between disruption of circadian rhythms and cancer development in humans. Mice lacking the circadian genes Period1 and 2 (Per) or Cryptochrome1 and 2 (Cry) are deficient in cell cycle regulation and ...

Research examining various psychological correlates of circadian type (also known as diurnal preference) has been, over the years, quite expansive. A notable omission within this research program would appear a systematic exploration of the relation between intelligence and morningness± eveningness. The present study redressed this imbalance. 420 participants performed two self-report inventori...

Research examining various psychological correlates of circadian type (also known as diurnal preference) has been, over the years, quite expansive. A notable omission within this research program would appear a systematic exploration of the relation between intelligence and morningness-eveningness. The present study redressed this imbalance. 420 participants performed two self-report inventorie...

In wild-type Drosophila, the period protein (PER) is found in nuclei of the eyes and brain, and PER immunoreactivity oscillates with a circadian rhythm. The studies described here indicate that the nuclear localization of PER is blocked by timeless (tim), a second chromosome mutation that, like per null mutations, abolishes circadian rhythms. PER fusion proteins without a conserved domain (PAS)...

Type 2 diabetes (T2D) is a complex disease driven by a combination of genetic and environmental factors. In recent years, several lines of evidence suggest that circadian disruption and sleep loss contribute to disease pathogenesis. Epidemiologic studies indicate that shift work is associated with an increased risk of T2D (1,2). Shift work is a prime example of circadian disruption, altering th...

It remains poorly understood how symptoms in allergic rhinitis are most severe during overnight or early in the morning. The circadian clock consisting of a network of several 'clock genes' including Clock drives daily rhythms in physiology. This study showed that allergen-induced surface CD203c expression on basophils in seasonal allergic rhinitis caused by Japanese cedar pollen exhibited a ti...

The molecular machinery that governs circadian rhythmicity comprises proteins whose interplay generates time-specific transcription of clock genes. The role of chromatin remodeling in a physiological setting such as the circadian clock is yet unclear. We show that the protein CLOCK, a central component of the circadian pacemaker, has histone acetyltransferase (HAT) activity. CLOCK shares homolo...