Defining the site of light perception and initiation of phototropism in Arabidopsis.

Phototropism is an adaptive response allowing plants to optimize photosynthetic light capture. This is achieved by asymmetric growth between the shaded and lit sides of the stimulated organ. In grass seedlings, the site of phototropin-mediated light perception is distinct from the site of bending; however, in dicotyledonous plants (e.g., Arabidopsis), spatial aspects of perception remain debatable. We use morphological studies and genetics to show that phototropism can occur in the absence of the root, lower hypocotyl, hypocotyl apex, and cotyledons. Tissue-specific expression of the phototropin1 (phot1) photoreceptor demonstrates that light sensing occurs in the upper hypocotyl and that expression of phot1 in the hypocotyl elongation zone is sufficient to enable a normal phototropic response. Moreover, we show that efficient phototropism occurs when phot1 is expressed from endodermal, cortical, or epidermal cells and that its local activation rapidly leads to a global response throughout the seedling. We propose that spatial aspects in the steps leading from light perception to growth reorientation during phototropism differ between grasses and dicots. These results are important to properly interpret genetic experiments and establish a model connecting light perception to the growth response, including cellular and morphological aspects.

The Perception of the Elements in the Hindu Traditions

The essays in this volume, contributions to an international symposium at the University of Lausanne in June 1998, represent the perception of the elements as a framework for the history of religions (Maya Burger), exemplified by the Hindu traditions. Each element is treated by a specialist in a different academic field in order to bring out a variety of approaches important to the discipline of the history of religion. Ether (akasa) was assigned to philosophy (Wilhelm Halbfass), wind to the history of religion (Bettina Bäumer), fire to classical philology (Peter Schreiner), water to a specialist on Indian medicine (Arion Rosu) and earth to anthropology (Gabriella Eichinger Ferro-Luzzi, specializing on Tamil literature). Les articles du présent volume, issus d'un symposium international ayant eu lieu à l'Université de Lausanne en juin 1998, présentent la perception des éléments comme base de recherche de l'étude des religions (Maya Burger), exemplifiée à l'aide des traditions hindoues. Chaque élément est traité par un spécialiste d'une discipline académique particulière dans le but de souligner la variété des approches nécessaire à la discipline d'histoire des religions. L'éther (akasa) a été considéré sous l'angle de la philosophie (Wilhelm Halbfass), le vent sous celui de l'histoire des religions (Bettina Bäumer), le feu sous celui de la philologie classique (Peter Schreiner), l'eau par un spécialiste de la médecine indienne (Arion Rosu) et la terre sous l'angle de l'anthropologie (Gabriella Eichinger Ferro-Luzzi, se concentrant sur la littérature tamoule).

GWAS of human bitter taste perception identifies new loci and reveals additional complexity of bitter taste genetics.

Human perception of bitterness displays pronounced interindividual variation. This phenotypic variation is mirrored by equally pronounced genetic variation in the family of bitter taste receptor genes. To better understand the effects of common genetic variations on human bitter taste perception, we conducted a genome-wide association study on a discovery panel of 504 subjects and a validation panel of 104 subjects from the general population of São Paulo in Brazil. Correction for general taste-sensitivity allowed us to identify a SNP in the cluster of bitter taste receptors on chr12 (10.88- 11.24 Mb, build 36.1) significantly associated (best SNP: rs2708377, P = 5.31 × 10(-13), r(2) = 8.9%, β = -0.12, s.e. = 0.016) with the perceived bitterness of caffeine. This association overlaps with-but is statistically distinct from-the previously identified SNP rs10772420 influencing the perception of quinine bitterness that falls in the same bitter taste cluster. We replicated this association to quinine perception (P = 4.97 × 10(-37), r(2) = 23.2%, β = 0.25, s.e. = 0.020) and additionally found the effect of this genetic locus to be concentration specific with a strong impact on the perception of low, but no impact on the perception of high concentrations of quinine. Our study, thus, furthers our understanding of the complex genetic architecture of bitter taste perception.

Decentralization, happiness and the perception of institutions

This paper analyses whether the different powers and resources at the disposal of local and regional governments across Europe deliver greater satisfaction with political institutions and lead to greater personal happiness. The analysis uses microdata from the four available waves of the European social survey (2002, 2004, 2006 and 2008), including more than 160,000 observations of individuals living in 29 European countries. Our results reveal that political and fiscal decentralization have a positive and significant effect on individuals’ overall happiness. Fiscal decentralization also exerts a significant effect on the level of satisfaction with political and economic institutions and with the education and health systems, whereas the effect of political decentralization on these variables is more limited. The results show that citizens seem to be happier with the actual capacity of their local governments to deliver than with the general principle that they can have a say on their daily politics and policies. Keywords: Happiness, well-being, satisfaction, fiscal and political decentralization, Europe. JEL codes: H11, H77

Stress Perception in Public Organizations: Expanding the Job Demands - Job Resources Model by Including Public Service Motivation

Although stress has been a longstanding issue in organizations and management studies, it has never been studied in relation to Public Service Motivation. This article therefore aims to integrate PSM into the job demands-job resources model of stress in order to determine whether PSM might contribute to stress in public organizations. Drawing upon original data from a questionnaire in a Swiss municipality, this study unsurprisingly shows that "red tape" is an antecedent of stress perception, whereas satisfaction with organizational support, positive feedback, and recognition significantly decrease the level of perceived stress. Astonishingly, the empirical results show that PSM is positively and significantly related to stress perception. By increasing individuals' expectations towards their jobs, PSM might thus contribute to increased pressure on public agents. Ultimately, this article investigates the "dark side" of PSM, which has been neglected by the literature thus far.

Experimental approaches in the targeting of photodynamic therapeutics

RÉSUMÉ : Chez l'homme, le manque de sélectivité des agents thérapeutiques représente souvent une limitation pour le traitement des maladies. Le ciblage de ces agents pour un tissu défini pourrait augmenter leur sélectivité et ainsi diminuer les effets secondaires en comparaison d'agents qui s'accumuleraient dans tout le corps. Cela pourrait aussi améliorer l'efficacité des traitements en permettant d'avoir une concentration localisée plus importante. Le ciblage d'agents thérapeutiques est un champ de recherche très actif. Les stratégies sont généralement basées sur les différences entre cellules normales et malades. Ces différences peuvent porter soit sur l'expression des molécules à leurs surfaces comme des récepteurs ou des transporteurs, soit sur les activités enzymatiques exprimées. Le traitement thérapeutique choisi ici est la thérapie photodynamique et est déjà utilisé pour le traitement de certains cancers. Cette thérapie repose sur l'utilisation de molécules qui réagissent à la lumière, les photosensibilisants. Elles absorbent l'énergie lumineuse et réagissent avec l'oxygène pour former des radicaux toxiques pour les cellules. Les photosensibilisants utilisés ici sont de deux natures : (i) soit ils sont tétrapyroliques (comme les porphyrines et chlorines), c'est à dire qu'ils sont directement activables par la lumière ; (ii) soit ce sont des prodrogues de photosensibilisants comme l'acide 5aminolévulinique (ALA) qui est transformé dans la cellule en protoporphyrine IX photosensibilisante. Dans le but d'augmenter la sélectivité des photosensibilisants, nous avons utilisé deux stratégies différentes : (i) le photosensibilisant est modifié par le greffage d'un agent de ciblage ; (ii) le photosensibilisant est incorporé dans des structures moléculaires de quelques centaines de nanomètres. Les sucres et l'acide folique sont des agents de ciblage largement établis et ont été utilisés ici car leurs récepteurs sont surexprimés à la surface de nombreuses cellules malades. Ainsi, des dérivés sucres ou acide folique de l'ALA ont été synthétisés et évalués in vitro sur de nombreuses lignées cellulaires cancéreuses. La stratégie utilisant l'acide folique est apparue incompatible avec l'utilisation de l'ALA puisque aucune photosensibilité n'a été induite par le composé. La stratégie utilisant les sucres a, par ailleurs, provoquée de bonnes photosensibilités mais pas d'augmentation de sélectivité. En parallèle, la combinaison entre les propriétés anticancéreuses des complexes métalliques au ruthénium avec les propriétés photosensibilisantes des porphyrines, a été évaluée. En effet, les thérapies combinées ont émergé il y a une dizaine d'années et représentent aujourd'hui de bonnes alternatives aux monothérapies classiques. Des ruthenium(I1)-arènes complexés avec la tetrapyridylporphyrine ont ainsi présenté de bonnes cytotoxicités et de bonnes phototoxicités pour des cellules de mélanomes. Des porphyrines ont aussi été compléxées avec des noyaux de diruthénium et ce type de dérivé a présenté de bonnes phototoxicités et une bonne sélectivité pour les cellules cancéreuses de l'appareil reproducteur féminin. L'incorporation de photosensibilisants tétrapyroliques a finalement été effectuée en utilisant des nanoparticules (NP) biocompatibles composées de chitosan et de hyaluronate. L'effet de ces NP a été évalué pour le traitement de la polyarthrite rhumatoïde (PR). Les NP ont d'abord été testées in vitro avec des macrophages de souris et les résultats ont mis en évidence de bonnes sélectivités et photosensibilités pour ces cellules. In vivo chez un modèle marin de la PR, l'utilisation de ces NP a révélé un plus grand temps de résidence des NP dans le genou de la souris en comparaison du temps obtenu avec le photosensibilisant seul. Le traitement par PDT a aussi démontré une bonne efficacité par ailleurs égale à celle obtenue avec les corticoïdes utilisés en clinique. Pour finir, les NP ont aussi démontré une bonne efficacité sur les myelomonocytes phagocytaires humains et sur les cellules contenues dans le liquide synovial de patients présentant une PR. Tous ces résultats suggèrent que les deux stratégies de ciblage peuvent être efficaces pour les agents thérapeutiques. Afm d'obtenir de bons résultats, il est toutefois nécessaire de réaliser une analyse minutieuse de la cible et du mode d'action de l'agent thérapeutique. Concernant les perspectives, la combinaison des deux stratégies c'est à dire incorporer des agents thérapeutiques dans des nanostructures porteuses d'agents de ciblage, représente probablement une solution très prometteuse. SUMMARY : In humans, the lack of selectivity of drugs and their high effective concentrations often represent limitations for the treatment of diseases. Targeting the therapeutical agents to a defined tissue could enhance their selectivity and then diminish their side effects when compared to drugs that accumulate in the entire body and could also improve treatment efûciency by allowing a localized high concentration of the agents. Targeting therapeutics to defined cells in human pathologies is a main challenge and a very active field of research. Strategies are generally based on the different behaviors and patterns of expression of diseased cells compared to normal cells such as receptors, proteases or trans-membrane carriers. The therapeutic treatment chosen here is the photodynamic therapy and is already used in the treatment of many cancers. This therapy relies on the administration of a photosensitizer (PS) which will under light, react with oxygen and induce formation of reactive oxygen species which are toxic for cells. The PSs used here are either tetrapyrolic (i. e. porphyries and chlorins) or prodrugs of PS (5-aminolevulinic acid precursor of the endogenous protoporphyrin Imo. In order to improve PS internalization and selectivity, we have used two different strategies: the modification of the PSs with diseased cell-targeting agents as well as their encapsulation into nanostructures. Sugars and folic acid are well established as targeting entities for diseased cells and were used here since their transporters are overexpressed on the surface of many cancer cells. Therefore sugar- and folic acid-derivatives of 5-aminolevulinic acid (ALA) were synthesized and evaluated in vitro in several cancer cell lines. The folic acid strategy appeared to be incompatible with ALA since no photosensitivity was induced while the strategy with sugars induced good photosensitivites but no increase of selectivity. Alternatively, the feasibility of combining the antineoplastic properties of ruthenium complexes with the porphyrin's photosensitizing properties, was evaluated since combined therapies have emerged as good alternatives to classical treatments. Tetrapyridylporphyrins complexed to ruthenium (I17 arenes presented good cytotoxicities and good phototoxicities toward melanoma cells. Porphyries were also complexed to diruthenium cores and this type of compound presented good phototoxicities and good selectivity for female reproductive cancer cells. The encapsulation of tetrapyrolic PSs was finally investigated using biocompatible nanogels composed of chitosan and hyaluronate. The behavior of these nanoparticles was evaluated for the treatment of rheumatoid arthritis (RA). They were first tested in vitro in mouse macrophages and results revealed good selectivities and phototoxicities toward these cells. In vivo in mice model of RA, the use of such nanoparticles instead of free PS showed longer time of residence in mice knees. Photodynamic protocols also demonstrated good efficiency of the treatment comparable to the corticoid injection used in the clinic. Finally our system was also efficient in human cells using phagocytic myelomonocytes or using cells of synovial fluids taken from patients with RA. Altogether, these results revealed that both strategies of modification or encapsulation of drugs can be successful in the targeting of diseased cells. However, a careful analysis of the target and of the mode of action of the drug, are needed in order to obtain good results. Looking ahead to the future, the combination of the two strategies (i.e. drugs loaded into nanostructures bearing the targeting agents) would represent probably the best solution.

Prendre des risques, ça rapporte ? Conduites à risques et perception des risques chez des adolescents tout-venant

Risk taking and its association with substance use by adolescents are often studied among clinical populations. The behavior of non-clinical adolescent samples is less well-known. According to some scholars, the adoption of risk behaviors can be predicted by a function of perceptions of both benefits and risks of such behaviors. However, the literature is still controversial about their respective significance. In this study, a non-clinical sample of 221 adolescents, aged 14 to 20, completed two questionnaires: the RIPS-R to estimate risk taking behaviors as well as perception of the risks and benefits of such behaviors, and the DEP-ADO to measure substance use. Our results show a high annual prevalence of socially accepted risk behaviors (drinking alcohol, not studying for exams, smoking tobacco). However, socially repressed behaviors (brawling, vandalism) are very occasional and are associated with problematic substance use. Globally, engagement in risk behaviors is more closely linked with the perceptions of its benefits than the perception of its risks. Finally, limitations and implications of these results for research and prevention are provided. Les prises de risques et leur association avec la consommation de substances chez les adolescents ont souvent été étudiées auprès de populations cliniques. Le comportement des jeunes tout-venant est en revanche moins bien connu. Selon certains théoriciens, la participation à des conduites à risques peut être déterminée en fonction des perceptions de leurs bénéfices et dangers potentiels. Toutefois, la littérature ne s'accorde pas sur l'importance respective que ces perceptions revêtent. Dans cette étude, 221 adolescents tout-venant, âgés de 14 à 20 ans, ont complété deux questionnaires : le RIPS-R pour évaluer la prise de risques et leur perception en termes de risques et de bénéfices, et la DEP-ADO pour mesurer la consommation de substances. Les résultats mettent en évidence une prévalence annuelle élevée des comportements à risques socialement acceptables (boire de l'alcool, fumer du tabac). En revanche, les comportements réprimés socialement (bagarres, actes de vandalisme) s'avèrent très occasionnels et sont associés à la consommation problématique de substances. Globalement, c'est la perception des bénéfices qui est le plus fortement liée au fait d'adopter un comportement à risque. Finalement, les limites et les implications pratiques de ces résultats sont discutées. © 2010 Elsevier Masson SAS. Tous droits réservés.

The gap between scientific evidence and clinical practice : 5-aminosalicylates are frequently used for the treatment of Crohn's disease

BACKGROUND: There is uncertain evidence of effectiveness of 5-aminosalicylates (5-ASA) to induce and maintain response and remission of active Crohn's disease (CD), and weak evidence to support their use in post-operative CD. AIM: To assess the frequency and determinants of 5-ASA use in CD patients and to evaluate the physicians' perception of clinical response and side effects to 5-ASA. METHODS: Data from the Swiss Inflammatory Bowel Disease Cohort, which collects data since 2006 on a large sample of IBD patients, were analysed. Information from questionnaires regarding utilisation of treatments and perception of response to 5-ASA were evaluated. Logistic regression modelling was performed to identify factors associated with 5-ASA use. RESULTS: Of 1420 CD patients, 835 (59%) were ever treated with 5-ASA from diagnosis to latest follow-up. Disease duration >10 years and colonic location were both significantly associated with 5-ASA use. 5-ASA treatment was judged to be successful in 46% (378/825) of treatment episodes (physician global assessment). Side effects prompting stop of therapy were found in 12% (98/825) episodes in which 5-ASA had been stopped. CONCLUSIONS: 5-Aminosalicylates were frequently prescribed in patients with Crohn's disease in the Swiss IBD cohort. This observation stands in contrast to the scientific evidence demonstrating a very limited role of 5-ASA compounds in the treatment of Crohn's disease.

Copwatching et perception publique de la police. L'intervention policière comme performance sous surveillance

Envisagée comme une situation sociale de rassemblement en rue, l'intervention policière se caractérise par sa nature publique et observable. Le « copwatching », en tant que pratique amateur de captation vidéo des interventions de police, problématise la visibilité des agents sur la voie publique en les soumettant à une surveillance médiatique. M'appuyant sur des exemples vidéos, j'explore les dimensions visuelles et symboliques du travail policier. De la performance policière en rue à la figuration médiatique du policier, l'étude des médiations entre action et image permet d'interroger la perception publique de la police engagée dans les rassemblements. Abstract Cop-watching and the public perception of the police. Police intervention as performance under surveillance. This paper deals with police work as a public performance on the street. Cop-watching, a way of publicly observing and documenting police activities, reveals the complex relationship between public perceptions of law enforcement and the visual nature of much police work. Three methodological approaches to cop-watching videos allow us to highlight the visual dimensions of police work : the study of mass-media images of cops, the study of street performance by real cops, and the study of the ways people make sense of the visual symbolic environment present in everyday police work.