Human Cryptochrome-1 Confers Light Independent Biological Activity in Transgenic Drosophila Correlated with Flavin Radical Stability

Cryptochromes are conserved flavoprotein receptors found throughout the biological kingdom with diversified roles in plant development and entrainment of the circadian clock in animals. Light perception is proposed to occur through flavin radical formation that correlates with biological activity in vivo in both plants and Drosophila. By contrast, mammalian (Type II) cryptochromes regulate the circadian clock independently of light, raising the fundamental question of whether mammalian cryptochromes have evolved entirely distinct signaling mechanisms. Here we show by developmental and transcriptome analysis that Homo sapiens cryptochrome - 1 (HsCRY1) confers biological activity in transgenic expressing Drosophila in darkness, that can in some cases be further stimulated by light. In contrast to all other cryptochromes, purified recombinant HsCRY1 protein was stably isolated in the anionic radical flavin state, containing only a small proportion of oxidized flavin which could be reduced by illumination. We conclude that animal Type I and Type II cryptochromes may both have signaling mechanisms involving formation of a flavin radical signaling state, and that light independent activity of Type II cryptochromes is a consequence of dark accumulation of this redox form in vivo rather than of a fundamental difference in signaling mechanism

NARROW CHANNEL EFFECT ON n- AND p-CHANNEL DEVICES FABRICATED WITH THE SILO AND BOX ISOLATION TECHNIQUES

Nous avons étudié l'effet canal étroit sur des dispositifs actifs fabriqués avec les techniques d'isolation SILO et BOX. L'importance de la diffusion latérale du bore dans la zone active est démontré, ainsi que l'avantage de la technique BOX, qui utilise un oxide déposé au lieu d'un oxide thermique dans le procédé SILO. En utilisant une dose d'implantation faible pour réduire l'effet canal étroit, un effet de double tension de seuil dans la caractéristique en faible inversion est inévitable.We have studied the narrow channel effect (NCE) on active devices fabricated with the SILO and BOX isolation techniques. The importance of the boron encroachment in the active region is shown, as well as the advantage of the BOX technique which uses a deposited oxide instead of a thermal oxide in the SILO process. With a low field implantation dose used to reduce the NCE, a double threshold effect in the subthreshold characteristic is inevitable

Recovery from eutrophic to oligotrophic states in lakes : role of sediments

Environmental contaminationInternational audienc