CONSTANS, a HUB for all seasons: How photoperiod pervades plant physiology regulatory circuits.

How does a plant detect the changing seasons and make important developmental decisions accordingly? How do they incorporate daylength information into their routine physiological processes? Photoperiodism, or the capacity to measure the daylength, is a crucial aspect of plant development that helps plants determine the best time of the year to make vital decisions, such as flowering. The protein CONSTANS (CO) constitutes the central regulator of this sensing mechanism, not only activating florigen production in the leaves but also participating in many physiological aspects in which seasonality is important. Recent discoveries place CO in the center of a gene network that can determine the length of the day and confer seasonal input to aspects of plant development and physiology as important as senescence, seed size, or circadian rhythms. In this review, we discuss the importance of CO protein structure, function, and evolutionary mechanisms that embryophytes have developed to incorporate annual information into their physiology.

Persulfidation protects from oxidative stress under nonphotorespiratory conditions in Arabidopsis.

Hydrogen sulfide is a signaling molecule in plants that regulates essential biological processes through protein persulfidation. However, little is known about sulfide-mediated regulation in relation to photorespiration. Here, we performed label-free quantitative proteomic analysis and observed a high impact on protein persulfidation levels when plants grown under nonphotorespiratory conditions were transferred to air, with 98.7% of the identified proteins being more persulfidated under suppressed photorespiration. Interestingly, a higher level of reactive oxygen species (ROS) was detected under nonphotorespiratory conditions. Analysis of the effect of sulfide on aspects associated with non- or photorespiratory growth conditions has demonstrated that it protects plants grown under suppressed photorespiration. Thus, sulfide amends the imbalance of carbon/nitrogen and restores ATP levels to concentrations like those of air-grown plants; balances the high level of ROS in plants under nonphotorespiratory conditions to reach a cellular redox state similar to that in air-grown plants; and regulates stomatal closure, to decrease the high guard cell ROS levels and induce stomatal aperture. In this way, sulfide signals the CO2 -dependent stomata movement, in the opposite direction of the established abscisic acid-dependent movement. Our findings suggest that the high persulfidation level under suppressed photorespiration reveals an essential role of sulfide signaling under these conditions.

Photoperiodic control of carbon distribution during the floral transition in Arabidopsis.

Flowering is a crucial process that demands substantial resources. Carbon metabolism must be coordinated with development through a control mechanism that optimizes fitness for any physiological need and growth stage of the plant. However, how sugar allocation is controlled during the floral transition is unknown. Recently, the role of a CONSTANS (CO) ortholog (Cr-CO) in the control of the photoperiod response in the green alga Chlamydomonas reinhardtii and its influence on starch metabolism was demonstrated. In this work, we show that transitory starch accumulation and glycan composition during the floral transition in Arabidopsis thaliana are regulated by photoperiod. Employing a multidisciplinary approach, we demonstrate a role for CO in regulating the level and timing of expression of the GRANULE BOUND STARCH SYNTHASE (GBSS) gene. Furthermore, we provide a detailed characterization of a GBSS mutant involved in transitory starch synthesis and analyze its flowering time phenotype in relation to its altered capacity to synthesize amylose and to modify the plant free sugar content. Photoperiod modification of starch homeostasis by CO may be crucial for increasing the sugar mobilization demanded by the floral transition. This finding contributes to our understanding of the flowering process.

The AtNHX1 exchanger mediates potassium compartmentation in vacuoles of transgenic tomato.

NHX-type antiporters in the tonoplast have been reported to increase the salt tolerance of various plants species, and are thought to mediate the compartmentation of Na(+) in vacuoles. However, all isoforms characterized so far catalyze both Na(+)/H(+) and K(+)/H(+) exchange. Here, we show that AtNHX1 has a critical involvement in the subcellular partitioning of K(+), which in turn affects plant K(+) nutrition and Na(+) tolerance. Transgenic tomato plants overexpressing AtNHX1 had larger K(+) vacuolar pools in all growth conditions tested, but no consistent enhancement of Na(+) accumulation was observed under salt stress. Plants overexpressing AtNHX1 have a greater capacity to retain intracellular K(+) and to withstand salt-shock. Under K(+)-limiting conditions, greater K(+) compartmentation in the vacuole occurred at the expense of the cytosolic K(+) pool, which was lower in transgenic plants. This caused the early activation of the high-affinity K(+) uptake system, enhanced K(+) uptake by roots, and increased the K(+) content in plant tissues and the xylem sap of transformed plants. Our results strongly suggest that NHX proteins are likely candidates for the H(+)-linked K(+) transport that is thought to facilitate active K(+) uptake at the tonoplast, and the partitioning of K(+) between vacuole and cytosol.

Setting the stage for school health-promoting programmes for deaf children in Spain.

Implementing health-promoting programmes for the most excluded and at-risk social groups forms a key part of any efforts to address underserved populations and reduce health inequalities in society. However, many at-risk children, particularly children in deaf communities, are not reached, or are poorly served, by health-promoting programmes within the school setting. This is so because schools are effective as health-promoting environments for d/Deaf children only to the extent that they properly address their unique communication needs and ensure they are both able and enabled to learn in a communication-rich and supportive psycho-social environment. This article examines how the usually separate strands of school health promotion and d/Deaf education might be woven together and illustrates research with deaf community members that involves them and gives their perspective. The primary objective of this study was to map deaf pilot bilingual education programmes in Spain-one of the first countries to ratify the Convention on the Rights of Persons with Disabilities (United Nations. (2006) Convention on the Rights of Persons with Disabilities, Resolution A/RES/61/106.)-with particular attention to their compliance to the Convention's article 24. Following pre-testing, 516 key informants were surveyed by mail (response rate: 42.08%) by using a snow-ball key-informant approach, within a Participatory Action Research framework, at a national, regional and local level. The results show that although some schools have achieved recommended standards, bilingual programmes are in various stages of formulation and implementation and are far from being equally distributed across the country, with only four regions concentrating more than 70% of these practices. This uneven geographical distribution of programmes probably reflects more basic differences in the priority given by regions, provinces, and municipalities to the deaf community's needs and rights as an important policy objective and may reinforce or widen inequalities by favouring or discriminating rather than achieving access and equity for this noticeably overlooked community.

Evolution of Daily Gene Co-expression Patterns from Algae to Plants.

Daily rhythms play a key role in transcriptome regulation in plants and microalgae orchestrating responses that, among other processes, anticipate light transitions that are essential for their metabolism and development. The recent accumulation of genome-wide transcriptomic data generated under alternating light:dark periods from plants and microalgae has made possible integrative and comparative analysis that could contribute to shed light on the evolution of daily rhythms in the green lineage. In this work, RNA-seq and microarray data generated over 24 h periods in different light regimes from the eudicot Arabidopsis thaliana and the microalgae Chlamydomonas reinhardtii and Ostreococcus tauri have been integrated and analyzed using gene co-expression networks. This analysis revealed a reduction in the size of the daily rhythmic transcriptome from around 90% in Ostreococcus, being heavily influenced by light transitions, to around 40% in Arabidopsis, where a certain independence from light transitions can be observed. A novel Multiple Bidirectional Best Hit (MBBH) algorithm was applied to associate single genes with a family of potential orthologues from evolutionary distant species. Gene duplication, amplification and divergence of rhythmic expression profiles seems to have played a central role in the evolution of gene families in the green lineage such as Pseudo Response Regulators (PRRs), CONSTANS-Likes (COLs), and DNA-binding with One Finger (DOFs). Gene clustering and functional enrichment have been used to identify groups of genes with similar rhythmic gene expression patterns. The comparison of gene clusters between species based on potential orthologous relationships has unveiled a low to moderate level of conservation of daily rhythmic expression patterns. However, a strikingly high conservation was found for the gene clusters exhibiting their highest and/or lowest expression value during the light transitions.

Characterization of the Sucrose Phosphate Phosphatase (SPP) Isoforms from Arabidopsis thaliana and Role of the S6PPc Domain in Dimerization.

Sucrose-phosphate phosphatase (SPP) catalyses the final step in the sucrose biosynthesis pathway. Arabidopsis thaliana genome codifies four SPP isoforms. In this study, the four Arabidopsis thaliana genes coding for SPP isoforms have been cloned, expressed in Escherichia coli and the kinetic and regulatory properties of the purified enzymes analysed. SPP2 is the isoform showing the highest activity, with SPP3b and SPP3a showing lower activity levels. No activity was detected for SPP1. We propose that this lack of activity is probably due to the absence of an essential amino acid participating in catalysis and/or in the binding of the substrate, sucrose-6-phosphate (Suc6P). The expression patterns of Arabidopsis SPP genes indicate that SPP2 and SPP3b are the main isoforms expressed in different tissues and organs, although the non-catalytic SPP1 is the main isoform expressed in roots. Thus, SPP1 could have acquired new unknown functions. We also show that the three catalytically active SPPs from Arabidopsis are dimers. By generating a chimeric SPP composed of the monomeric cyanobacterial SPP fused to the higher plant non-catalytic S6PPc domain (from SPP2), we show that the S6PPc domain is responsible for SPP dimerization. This is the first experimental study on the functionality and gene expression pattern of all the SPPs from a single plant species.

[Changes in homecare for preterm and low-birth-weight infants from 2002 to 2014]. / Evolución de la atención a domicilio para niños prematuros y de bajo peso de nacimiento desde 2002 hasta 2014.

INTRODUCTION: Homecare (HC) is a service offering home medical and nursing care to the patient at home in equal quantity and quality as in the hospital. The aim of the article is to describe the changes in the HC of preterm and full-term low-birth-weight infants in our department from 2002-2014. MATERIAL AND METHODS: The HC database is revised. The characteristics of the newborns and the social characteristics of the family in three consecutive time periods are analysed. A satisfaction survey of parents is also presented. RESULTS: The main changes in HC include a decrease in the weight at discharge (from 1880g in the 2002-2006 period to 1850g in the 2011-2014 period; P=.006) and at the end of HC (from 2187g to 2163g; P=.001), an increase in the duration of HC (from 10 to 11 days; P=.007) and a lower incidence of new hospitalization (from 3.4% to 1.3%; P=.019) The social characteristics of the family show a higher maternal age with more previous alive children, a family context better suited with a more appropriate housing, and an increase in exclusive breastfeeding at hospital discharge (from 25.5% to 49.0%; P<.001). The overall assessment of the program is ≥7/10 in 98.8% of responses. CONCLUSIONS: The results of the HC of preterm and low-birth-weight infants have improved over time, saving approximately 10-11 days of hospitalisation, and without compromising the quality of care or reducing family satisfaction.