Revised Morning Loops of the Arabidopsis Circadian Clock Based on Analyses of Direct Regulatory Interactions

The network structure of the plant circadian clock is complex and direct regulatory interactions between individual components have proven particularly difficult to predict from genetic analyses. Here, we systematically investigate in vivo binding interactions between the morning-specific transcription factor, LATE ELONGATED HYPOCOTYL (LHY) and the promoters of other components of the network. We then demonstrate the functionality of these interactions by testing the responsiveness of the target gene to an ethanol-induced change in expression level of the LHY protein. We uncover novel, negative autoregulatory feedback loops from LHY and the closely related CIRCADIAN CLOCK ASSOCIATED-1 (CCA1) onto their own and each other’s expression. Furthermore we show that LHY acts as a repressor of all other clock components, including PSEUDO-RESPONSE REGULATORs (PRRs) 9 and 7, which were previously thought to be positive regulatory targets. These experimental results lead to a substantial revision of the morning loops of the clock

L’acrobatica del morire

This article aims at summing up the reflections of a small group of psychologists who work in the domain of palliative treatment. The theory and methodology supporting it are borrowed by a group analysis approach; purpose of the group is a research based on the workers’ experience elaboration, which aims at finding out both the specificities of the work apparatus with the people accompanied to the conclusion of their lives, and the main thematic areas of the relationship between health care team, patients and families. The work we present aims at introducing the most meaningful themes emerged during group meetings: first of all some service criticalities examined in the area of terminal health care and the workers’ possible saturation and psycho-social discomfort quotas, generating in some cases a common sense of professional precariousness

Interactions between circadian rhythms, ROS and redox

Circadian rhythms are endogenous biological cycles with a period of about 24 h. In plants, circadian rhythms have a pervasive influence upon metabolism, physiology and development, yet we are still discovering how these rhythms interact with reactive oxygen species (ROS) generation and signalling. Recent work has identified circadian rhythms of ROS generation and ROS-scavenging enzymes, and there are also circadian rhythms of ROS-generating photosynthesis. Here, we summarise our current understanding of the relationship between the circadian system and ROS, and suggest roles for ROS in circadian signalling between organelles and the circadian regulation of guard cell function. There are circadian rhythms of peroxiredoxin oxidation state that occur in the absence of transcription and translation. It seems that there could be multiple levels of integration between ROS, redox and circadian regulation