Homologs of the Drosophila clock gene per have recently been cloned in Lepidopteran and Blattarian insect species. To assess the extent to which clock mechanisms are conserved among phylogenetically distant species, we determined whether PER protein from the silkmoth Antheraea pernyi can function in the Drosophila circadian timing system. When expressed in transgenic Drosophila, the silkmoth PE...

INTRODUCTION The timing and quality of sleep are controlled by the interaction of a homeostatic process, that tracks sleep need as a function of the previous sleep/wake history, and a circadian process that ensures the appropriate timing of sleep relative to the daily light-dark alternation.1,2 Although these two processes seem functionally and neurophysiologically distinct, at the molecular le...

Like the biological clock in the body, replication of each cell type (even different cells of the same organism) follows a timing program. Abnormal function of this timer could be an alarm for a disease like cancer. DNA replication starts from a specific point on the chromosome that is called the origin of replication. In contrast to prokaryotes in which DNA replication starts from a single ...

BACKGROUND Talitrus saltator is an amphipod crustacean that inhabits the supralittoral zone on sandy beaches in the Northeast Atlantic and Mediterranean. T. saltator exhibits endogenous locomotor activity rhythms and time-compensated sun and moon orientation, both of which necessitate at least one chronometric mechanism. Whilst their behaviour is well studied, currently there are no description...

INTRODUCTION Patients with rheumatoid arthritis (RA) have disturbances in the hypothalamic-pituitary-adrenal (HPA) axis. These are reflected in altered circadian rhythm of circulating serum cortisol, melatonin and IL-6 levels and in chronic fatigue. We hypothesized that the molecular machinery responsible for the circadian timekeeping is perturbed in RA. The aim of this study was to investigate...

Circadian rhythms drive the temporal organization of a wide variety of physiological and behavioral functions in ∼24-h cycles. This control is achieved through a complex program of gene expression. In mammals, the molecular clock machinery consists of interconnected transcriptional-translational feedback loops that ultimately ensure the proper oscillation of thousands of genes in a tissue-speci...