Search results for "IRC"

Modulating Neuronal Competition Dynamics in the Dentate Gyrus to Rejuvenate Aging Memory Circuits.

2015

The neural circuit mechanisms underlying the integration and functions of adult-born dentate granule cell (DGCs) are poorly understood. Adult-born DGCs are thought to compete with mature DGCs for inputs to integrate. Transient genetic overexpression of a negative regulator of dendritic spines, Kruppel-like factor 9 (Klf9), in mature DGCs enhanced integration of adult-born DGCs and increased NSC activation. Reversal of Klf9 overexpression in mature DGCs restored spines and activity and reset neuronal competition dynamics and NSC activation, leaving the DG modified by a functionally integrated, expanded cohort of age-matched adult-born DGCs. Spine elimination by inducible deletion of Rac1 in …

Ocular Clocks: Adapting Mechanisms for Eye Functions and Health

2018

Vision is a highly rhythmic function adapted to the extensive changes in light intensity occurring over the 24-hour day. This adaptation relies on rhythms in cellular and molecular processes, which are orchestrated by a network of circadian clocks located within the retina and in the eye, synchronized to the day/night cycle and which, together, fine-tune detection and processing of light information over the 24-hour period and ensure retinal homeostasis. Systematic or high throughput studies revealed a series of genes rhythmically expressed in the retina, pointing at specific functions or pathways under circadian control. Conversely, knockout studies demonstrated that the circadian clock re…

zHSF1 modulates zper2 expression in zebrafish embryos

2018

International audience; HSF1 is a transcription factor that plays a key role in circadian resetting by temperature. We have used zebrafish embryos to decipher the roles of zHsf1, heat and light on zper2 transcription in vivo. Our results show that heat shock (HS) stimulated zper2 expression in the dark but has no cumulative effect combined with light. After light exposition, zper2 expression was 2.7 fold increased threefold in the hsf1-morphants in comparison to control embryos. Our results show that zHsf1 plays a positive role in HS-driven expression of zper2 in the dark but seems to act as an attenuator in the presence light.

Sleep, alertness and alertness management among commercial airline pilots on short-haul and long-haul flights

2016

Item does not contain fulltext Airline pilots' sleep and on-duty alertness are important focus areas in commercial aviation. Until now, studies pertaining to this topic have mainly focused on specific characteristics of flights and thus a comprehensive picture of the matter is not well established. In addition, research knowledge of what airline pilots actually do to maintain their alertness while being on duty is scarce. To address these gaps in research knowledge, we conducted a field study on a representative sample of the airline pilots of a medium-sized airline. The sample consisted of 90 pilots, of whom 30 flew long-haul (LH) routes, 30 short-haul (SH) routes, and 30 flew both. A tota…

Reinforcement learning in synthetic gene circuits.

2020

Synthetic gene circuits allow programming in DNA the expression of a phenotype at a given environmental condition. The recent integration of memory systems with gene circuits opens the door to their adaptation to new conditions and their re-programming. This lays the foundation to emulate neuromorphic behaviour and solve complex problems similarly to artificial neural networks. Cellular products such as DNA or proteins can be used to store memory in both digital and analog formats, allowing cells to be turned into living computing devices able to record information regarding their previous states. In particular, synthetic gene circuits with memory can be engineered into living systems to al…

2019

Cryptochromes are blue-light photoreceptor proteins, which provide input to circadian clocks. The cryptochrome from Drosophila melanogaster (DmCry) modulates the degradation of Timeless and itself. It is unclear how light absorption by the chromophore and the subsequent redox reactions trigger these events. Here, we use nano- to millisecond time-resolved x-ray solution scattering to reveal the light-activated conformational changes in DmCry and the related (6-4) photolyase. DmCry undergoes a series of structural changes, culminating in the release of the carboxyl-terminal tail (CTT). The photolyase has a simpler structural response. We find that the CTT release in DmCry depends on pH. Mutat…

The C-terminal domain of ParB is critical for dynamic DNA binding and bridging interactions which condense the bacterial centromere

2017

SUMMARYThe ParB protein forms DNA bridging interactions aroundparSto form networks which condense DNA and earmark the bacterial chromosome for segregation. The mechanism underlying the formation of ParB nucleoprotein complexes is unclear. We show here that the central DNA binding domain is essential for anchoring atparS, and that this interaction is not required for DNA condensation. Structural analysis of the C-terminal domain reveals a dimer with a lysine-rich surface that binds DNA non-specifically and is essential for DNA condensationin vitro. Mutation of either the dimerisation or the DNA binding interface eliminates ParB foci formationin vivo. Moreover, the free C-terminal domain can …

Arctic aerosols and the ‘Divergence Problem’ in dendroclimatology

2021

Considering the importance and complexity of natural (e.g., volcanic eruptions and wildfires) and anthropogenic (e.g., mining, oil and shipping industries) aerosol emissions to Arctic warming is particularly timely given the recent temperature extremes recorded at high-northern latitudes (Cohen et al., 2020; Overland and Wang, 2021). Despite our knowledge about the observed and modelled climatic effects of rising Arctic aerosol concentrations (Schmale et al., 2021), which may exhibit regional and seasonal differences and call for diverse research priorities from local to circumpolar scales, we feel that the ecological consequences of an aerosol-induced reduction in surface irradiance (i.e.,…

Le goût sucré, de l’enfance… à la dépendance ?

2013

Summary: Can one talk about addiction to sugar? Sugar is an important part of our diet, and an important source of pleasure, as of a young age. The definition of addiction involves that addictive substances act on the reward circuit, and lead to two symptoms, withdrawal and tolerance. Is it the case with sugar? According to the literature, brain activations in regions involved in the reward circuit are observed in response to “sugar”, and they differ according to the type of sugar (caloric carbohydrates, sweet or not; sweeteners). Besides, withdrawal and tolerance symptoms are not well characterized: food cravings often concern sweet foods, but there is a decrease with age of the preference…

Cross-border mobility and long-distance communication as modes of care circulation: insights from the Peruvian ‘zero generation’

2016

ABSTRACTThe contribution of older family members in the sending countries to the well-being of transnational families has only recently come more into the focus of research. Cross-border mobility and long-distance communication are two central modes through which the members of this ‘zero generation’ engage in transnational family life. By applying the framework of care circulation, this paper seeks to discuss the influence of cross-border mobility and long-distance communication on older Peruvian non-migrants’ engagement in transnational family care arrangements. The paper shows, first, that political and economic factors, as well as communication infrastructures, shape the patterns of the…