Phytochrome interacting factors 4 and 5 control seedling growth in changing light conditions by directly controlling auxin signaling.

Plant growth is strongly influenced by the presence of neighbors that compete for light resources. In response to vegetational shading shade-intolerant plants such as Arabidopsis display a suite of developmental responses known as the shade-avoidance syndrome (SAS). The phytochrome B (phyB) photoreceptor is the major light sensor to mediate this adaptive response. Control of the SAS occurs in part with phyB, which controls protein abundance of phytochrome-interacting factors 4 and 5 (PIF4 and PIF5) directly. The shade-avoidance response also requires rapid biosynthesis of auxin and its transport to promote elongation growth. The identification of genome-wide PIF5-binding sites during shade avoidance revealed that this bHLH transcription factor regulates the expression of a subset of previously identified SAS genes. Moreover our study suggests that PIF4 and PIF5 regulate elongation growth by controlling directly the expression of genes that code for auxin biosynthesis and auxin signaling components

Magneto-Acoustic Wave Oscillations in Solar Spicules

Some observations suggest that solar spicules show small amplitude and high frequency oscillations of magneto-acoustic waves, which arise from photospheric granular forcing. We apply the method of MHD seismology to determine the period of kink waves. For this purposes, the oscillations of a magnetic cylinder embedded in a field-free environment is investigated. Finally, diagnostic diagrams displaying the oscillatory period in terms of some equilibrium parameters are provided to allow a comparison between theoretical results and those coming from observations.Comment: 10 pages, 4 fig

An evaluation of Mg/Ca, Sr/Ca, and Ba/Ca ratios as environmental proxies in aragonite bivalve shells

International audienceThe influence of salinity and water chemistry on Mg/Ca, Sr/Ca, and Ba/Ca ratios in the aragonitic shells of the Manila clam was investigated. Clams were reared at constant temperature (20°C) under different controlled conditions of salinity, commonly encountered in their natural habitat. Clams were held in three tanks with a constant salinity of 35 for the first 35days, and then two tanks were changed to lower salinities (20 and 28) for the next 29days. Individual shell Mg/Ca, Sr/Ca, and Ba/Ca ratios were studied through time. Despite stable conditions (temperature, salinity, and Mg/Cawater) for clams reared at salinity 35 during the experiment, Mg/Ca shell ratios increased through the time. Moreover the salinity decrease at t35 slowed the increase of Mg/Ca shell ratios at salinity 28 and resulted in an Mg/Cashell decrease at salinity 20, despite similar Mg/Cawater ratios in the different salinity treatments. Microprobe analyses illustrate that Mg varies along contemporaneous growth lines. The variable shell Mg/Ca ratios suggest that incorporation of magnesium into shell carbonate is strongly regulated by the organism and not by environmental conditions. Interestingly, microprobe analyses illustrated that Mg was not associated with shell sulfur as other studies have suggested. Sr/Ca shell ratios of clams reared at salinity 35 and under constant conditions were also not as constant as expected if Sr/Ca ratios were an environmental proxy. There was an inverse correlation between shell Sr/Ca and salinity despite a slight positive correlation between salinity and Sr/Ca ratios of the water, indicating that Sr/Ca ratios do not reflect environmental conditions. A strong inverse correlation between salinity and Ba/Ca shell ratios (and a positive correlation between Ba/Ca shell and Ba/Ca water) was observed. Therefore, Ba/Ca shell ratios seem to be a promising proxy of high-resolution (1day) salinity variations in estuarine waters (via the relationship between Ba/Ca water and salinity). This study clearly illustrates that both Mg/Ca and Sr/Ca ratios in aragonite shells are not under environmental control and that Ba/Ca ratios are, with the later tracking high-resolution water Ba/Ca ratios and hence estuarine salinity variations

Supplementary Material for: Alterations in Monocyte Phenotypes and Functions after a Hip Fracture in Elderly Individuals: A 6-Month Longitudinal Study

<b><i>Background:</i></b> Healthy elderly individuals are particularly prone to catastrophic events at any moment of their lives. One stressful event for individuals aged 65 and older is a fall that results in a fracture of the hip (HF). HF causes a state of inflammation that may affect immune responses. In this connection, we have reported that HF induced alterations in neutrophil functions. <b><i>Objective:</i></b> To assess the impact of HF on classical (cM), intermediate (iM) and non-classical (ncM) monocyte subsets. <b><i>Methods:</i></b> Distribution, functions (chemotaxis, phagocytosis, superoxide production and cytokine production), phenotype and activation (NF-κB and PI3K) were evaluated in monocyte subsets before surgery and 6 weeks and 6 months after the event. <b><i>Results:</i></b> The distribution of cM and ncM was unchanged, but iM transiently increased before surgery. Sustained increases (iM response to CCL2 and CX3CL1) and decreases (cM and ncM response to CCL2) in chemotaxis were observed. Phagocytosis and superoxide production were impaired in cM but not in iM or ncM. Sustained expression of HLA-DR occurred in cM but not in iM and ncM. Sustained decreased expression of CD11b occurred only in ncM. Sustained decreases (cM and ncM) and increases (iM) in CCR2 expression were observed. An elevated expression of CX3CR1 was found only in iM. cM produced elevated quantities of TNFα. There was a transient oxidative burst of production before surgery in iM and a sustained decrease in ncM. IL-10 production was severely impaired in cM and decreased in iM prior to surgery. Sustained activation (cM), inhibition (ncM) and transient activation (iM) of NF-κB were observed. Activation of PI3K was severely impaired in cM and ncM but was sustained in iM. <b><i>Conclusion:</i></b> HF had more impact on cM and ncM functions than on iM. HF triggered a switch in cM functions from phagocytic to inflammatory elevated TNFα-producing cells. These changes may impact clinical outcomes of HF with respect to inflammation, opportunistic infections and physical recovery