How do organisms sense metabolic and nutrient status to set their biological clocks? The significance of recent work showing that nutrient-sensing pathways influence central circadian clocks in Drosophila is discussed.

adds, and dealt, in part, with the importance of the structure of fatty acids both as components of animal diets and animal tissue and as factors in blood coagulation and thrombosis. The second symposium discussed the newer techniques used to study lipids, especially the recent developments in gas-liquid, liquid-solid, and thin-layer chromatography. From the brief summary given above, it will b...

Animals with habitats within the intertidal zone are exposed to environmental cycles that include the ebb and flow of tidal waters, changes in tidal levels associated with the lunar month, the light-dark cycle and the alternation of seasons. This intricate temporal environment results in the selection of biological timing systems with endogenous clocks that can oscillate with this wide range of...

Life evolved on earth slowly over a few billions of years. During this time, and before, the earth has been rotating around its own tilted axis and simultaneously revolving around the sun. Thus, it is no surprise that the periodic environmental consequences of the rotation (day and night), the tilt (changing day length) and of the revolution (seasons) should influence life-forms right from thei...

Data presented in this paper test the hypotheses that Hirsch’s positive geotaxis (Lo) and negative geotaxis (Hi5) strains of Drosophila melanogaster (fruit fly) differ in length of the free-running circadian activity period (tau) as well as adult geotaxis. Several genes have been shown to alter geotaxis in Drosophila. Two of these genes, cryptochrome (cry) and Pigment-dispersing-factor (Pdf) ar...