Gender bias in the assessment of physical activity in population studies

Summary: Objectives: Despite their generally more health promoting behaviours, women are found to participate less in physical activity than men. This study explores possible gender bias in measurement of physical activity in population studies. Methods: Data collected by telephone (CATI) from the Berne Lifestyle Panel in 1996 is utilised. A representative sample of the population of the city of Berne comprised N=1119 cases. Gender differences are assessed for the weekly frequency of three measurements of physical activities. Results: An indicator of sport and exercise showed higher physical activity among men, while the indicator of habitual physical activity showed higher rates of daily walking and biking among women. A combined indicator of general physical activity showed no significant gender differences. Conclusions: The results provide empirical evidence on potential risk of underestimation of physical activity among women and of misclassification with respect to high or low risk behaviour pattern

Genome-wide comparative analysis of the IQD gene families in Arabidopsis thaliana and Oryza sativa

BACKGROUND: Calcium signaling plays a prominent role in plants for coordinating a wide range of developmental processes and responses to environmental cues. Stimulus-specific generation of intracellular calcium transients, decoding of calcium signatures, and transformation of the signal into cellular responses are integral modules of the transduction process. Several hundred proteins with functions in calcium signaling circuits have been identified, and the number of downstream targets of calcium sensors is expected to increase. We previously identified a novel, calmodulin-binding nuclear protein, IQD1, which stimulates glucosinolate accumulation and plant defense in Arabidopsis thaliana. Here, we present a comparative genome-wide analysis of a new class of putative calmodulin target proteins in Arabidopsis and rice. RESULTS: We identified and analyzed 33 and 29 IQD1-like genes in Arabidopsis thaliana and Oryza sativa, respectively. The encoded IQD proteins contain a plant-specific domain of 67 conserved amino acid residues, referred to as the IQ67 domain, which is characterized by a unique and repetitive arrangement of three different calmodulin recruitment motifs, known as the IQ, 1-5-10, and 1-8-14 motifs. We demonstrated calmodulin binding for IQD20, the smallest IQD protein in Arabidopsis, which consists of a C-terminal IQ67 domain and a short N-terminal extension. A striking feature of IQD proteins is the high isoelectric point (~10.3) and frequency of serine residues (~11%). We compared the Arabidopsis and rice IQD gene families in terms of gene structure, chromosome location, predicted protein properties and motifs, phylogenetic relationships, and evolutionary history. The existence of an IQD-like gene in bryophytes suggests that IQD proteins are an ancient family of calmodulin-binding proteins and arose during the early evolution of land plants. CONCLUSION: Comparative phylogenetic analyses indicate that the major IQD gene lineages originated before the monocot-eudicot divergence. The extant IQD loci in Arabidopsis primarily resulted from segmental duplication and reflect preferential retention of paralogous genes, which is characteristic for proteins with regulatory functions. Interaction of IQD1 and IQD20 with calmodulin and the presence of predicted calmodulin binding sites in all IQD family members suggest that IQD proteins are a new class of calmodulin targets. The basic isoelectric point of IQD proteins and their frequently predicted nuclear localization suggest that IQD proteins link calcium signaling pathways to the regulation of gene expression. Our comparative genomics analysis of IQD genes and encoded proteins in two model plant species provides the first step towards the functional dissection of this emerging family of putative calmodulin targets

Comparative expression profiling reveals a role of the root apoplast in local phosphate response

BACKGROUND Plant adaptation to limited phosphate availability comprises a wide range of responses to conserve and remobilize internal phosphate sources and to enhance phosphate acquisition. Vigorous restructuring of root system architecture provides a developmental strategy for topsoil exploration and phosphate scavenging. Changes in external phosphate availability are locally sensed at root tips and adjust root growth by modulating cell expansion and cell division. The functionally interacting Arabidopsis genes, LOW PHOSPHATE RESPONSE 1 and 2 (LPR1/LPR2) and PHOSPHATE DEFICIENCY RESPONSE 2 (PDR2), are key components of root phosphate sensing. We recently demonstrated that the LOW PHOSPHATE RESPONSE 1 - PHOSPHATE DEFICIENCY RESPONSE 2 (LPR1-PDR2) module mediates apoplastic deposition of ferric iron (Fe3+) in the growing root tip during phosphate limitation. Iron deposition coincides with sites of reactive oxygen species generation and triggers cell wall thickening and callose accumulation, which interfere with cell-to-cell communication and inhibit root growth. RESULTS We took advantage of the opposite phosphate-conditional root phenotype of the phosphate deficiency response 2 mutant (hypersensitive) and low phosphate response 1 and 2 double mutant (insensitive) to investigate the phosphate dependent regulation of gene and protein expression in roots using genome-wide transcriptome and proteome analysis. We observed an overrepresentation of genes and proteins that are involved in the regulation of iron homeostasis, cell wall remodeling and reactive oxygen species formation, and we highlight a number of candidate genes with a potential function in root adaptation to limited phosphate availability. Our experiments reveal that FERRIC REDUCTASE DEFECTIVE 3 mediated, apoplastic iron redistribution, but not intracellular iron uptake and iron storage, triggers phosphate-dependent root growth modulation. We further highlight expressional changes of several cell wall-modifying enzymes and provide evidence for adjustment of the pectin network at sites of iron accumulation in the root. CONCLUSION Our study reveals new aspects of the elaborate interplay between phosphate starvation responses and changes in iron homeostasis. The results emphasize the importance of apoplastic iron redistribution to mediate phosphate-dependent root growth adjustment and suggest an important role for citrate in phosphate-dependent apoplastic iron transport. We further demonstrate that root growth modulation correlates with an altered expression of cell wall modifying enzymes and changes in the pectin network of the phosphate-deprived root tip, supporting the hypothesis that pectins are involved in iron binding and/or phosphate mobilization

The Berne-Munich Lifestyle Panel: Background and baseline results from a longitudinal health lifestyle survey

Summary: The Berne-Munich Lifestyle Panel (BMLP) studies health relevant lifestyles among some 2000 adults in Switzerland and Germany. This paper introduces the theoretical background and empirical concept of the BMLP. Sociological theory provided the guidelines for the development of an empirical model that measures structures and dynamics of health lifestyles. Health lifestyles are explained as the product of the complex interplay between health related behaviours, orientations and social resources. Residents of Berne (Switzerland) and Munich (Germany) in the age between 55 and 65 years were contacted in 12 months periods and interviewed by telephone (CATI). The questionnaire comprised some 200 questions on selected aspects of health lifestyles and health status. Interviews were conducted in two waves in Munich (1996 and 1997) and three waves in Berne (1996/97/98). The paper reports findings from baseline data analysis and explores cultural differentiations with respect to the distribution of 1. health relevant behaviours, orientations and social resources, 2. triggers of lifestyle change (life events), 3. mediating factors (Health Locus of Control, Sense of Coherence). Initial results from the search for patterns of health behaviours are also reported. The findings show considerable differences but also impressive similarities in health lifestyle elements across the two samples. There is also preliminary evidence for meaningful patterns of health behaviours in the cohort under investigation. Moreover, the findings clearly demonstrate the need for a gender specific approach in the analysis of cultural differences in health behaviours and lifestyle

The Arabidopsis Synaptotagmin1 is enriched in endoplasmic reticulum-plasma membrane contact sites and confers cellular resistance to mechanical stresses

Eukaryotic endoplasmic reticulum (ER)-plasma membrane (PM) contact sites are evolutionarily conserved microdomains that have important roles in specialized metabolic functions such as ER-PM communication, lipid homeostasis, and Ca2+ influx. Despite recent advances in knowledge about ER-PM contact site components and functions in yeast (Saccharomyces cerevisiae) and mammals, relatively little is known about the functional significance of these structures in plants. In this report, we characterize the Arabidopsis (Arabidopsis thaliana) phospholipid binding Synaptotagmin1 (SYT1) as a plant ortholog of the mammal extended synaptotagmins and yeast tricalbins families of ER-PM anchors. We propose that SYT1 functions at ER-PM contact sites because it displays a dual ER-PM localization, it is enriched in microtubule-depleted regions at the cell cortex, and it colocalizes with Vesicle-Associated Protein27-1, a known ER-PM marker. Furthermore, biochemical and physiological analyses indicate that SYT1 might function as an electrostatic phospholipid anchor conferring mechanical stability in plant cells. Together, the subcellular localization and functional characterization of SYT1 highlights a putative role of plant ER-PM contact site components in the cellular adaptation to environmental stresses

Plasma membrane lipid remodeling during cold acclimation is mediated by the ER-PM contact sites-localized synaptotagmins 1 and 3

Cold acclimation is the capacity of certain plants to increase their freezing tolerance in response to a period of low non-freezing temperatures. Cold acclimation involves a series of biochemical and physiological adaptations, including a deep transcriptional reprogramming and drastic changes in the lipid composition of cellular membranes in order to prevent the freeze-induced damage (1). While a profound knowledge has been acquired on the regulation of gene expression triggered by cold-acclimation, very little is known about the mechanisms governing the cold-induced changes in membranes’ lipid composition. In this study we report that in Arabidopsis, the constitutively expressed Synaptotagmin 1 (SYT1) and the cold-induced homolog Synaptotagmin 3 (SYT3) are essential for cold- acclimated freezing tolerance and for the lipid remodelling of the plasma membrane during cold-acclimation. SYT1 and SYT3 are phospholipid-binding proteins located in Endoplasmic Reticulum-Plasma Membrane contact sites (ER-PMcs), conserved structures defined as regions of the cortical ER in close apposition to the PM (2). ER-PMcs facilitate the non-vesicular lipid transport between ER and PM in yeast and mammals, and are essential for lipid homeostasis (3). In contrast to the high and ubiquitous SYT1 expression, SYT3 expression is low and mainly restricted to meristemoids, young stomata, and old primary root. TIRF microscopy analyses show that during cold acclimation there is an increase of SYT1::SYT1:GFP and SYT3::SYT3:GFP signals as spots at the PM. High-resolution lipidome analyses show the over-accumulation of phosphatidylinositols phosphate (PIPs) and glycerolipids in vivo in syt1 and specially syt1/syt3 mutant plants compared to WT in one-week cold-acclimated plants. Interestingly, protein-lipid overlay assays (membrane-strips and PIP-strips) reveal PIPs and glycerolipids as major interactors for both, SYT1 and SYT3. Here we show that 1) Arabidopsis SYT1 and SYT3 are induced by cold, 2) SYT1 and SYT3 localize to ER-PMcs, 3) the specific lipids that directly interact with SYT1 and SYT3 accumulate in syt1/syt3 mutant after cold acclimation, and 4) syt1/syt3 show reduced cold acclimated freezing tolerance. We propose that SYT1 and SYT3 have essential roles in ER-PMcs mediated lipid remodelling during cold acclimation, which in turn leads to freezing tolerance.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Iron and Phosphate Deficiency Regulators Concertedly Control Coumarin Profiles in Arabidopsis thaliana Roots During Iron, Phosphate, and Combined Deficiencies

Plants face varying nutrient conditions, to which they have to adapt to. Adaptive responses are nutrient-specific and strategies to ensure supply and homeostasis for one nutrient might be opposite to another one, as shown for phosphate (Pi) and iron (Fe) deficiency responses, where many genes are regulated in an opposing manner. This was also observed on the metabolite levels. Whereas root and exudate levels of catechol-type coumarins, phenylpropanoid-derived 2-benzopyranones, which facilitate Fe acquisition, are elevated after Fe deficiency, they are decreased after Pi deficiency. Exposing plants to combined Pi and Fe deficiency showed that the generation of coumarin profiles in Arabidopsis thaliana roots by Pi deficiency considerably depends on the availability of Fe. Similarly, the effect of Fe deficiency on coumarin profiles is different at low compared to high Pi availability. These findings suggest a fine-tuning of coumarin profiles, which depends on Fe and Pi availability. T-DNA insertion lines exhibiting aberrant expression of genes involved in the regulation of Pi starvation responses (PHO1, PHR1, bHLH32, PHL1, SPX1) and Fe starvation responses (BRUTUS, PYE, bHLH104, FIT) were used to analyze the regulation of the generation of coumarin profiles in Arabidopsis thaliana roots by Pi, Fe, and combined Pi and Fe deficiency. The analysis revealed a role of several Fe-deficiency response regulators in the regulation of Fe and of Pi deficiency-induced coumarin profiles as well as for Pi deficiency response regulators in the regulation of Pi and of Fe deficiency-induced coumarin profiles. Additionally, the regulation of Fe deficiency-induced coumarin profiles by Fe deficiency response regulators is influenced by Pi availability. Conversely, regulation of Pi deficiency-induced coumarin profiles by Pi deficiency response regulators is modified by Fe availability