Caractérisation de la fonction de CNK dans la régulation du mécanisme de signalisation du module MAPK/ERK chez la drosophile

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Localisation subcellulaire de la protéine kinase ZPK et identification de l'un de ses partenaires protéiques

La protéine ZPK est une sérine/thréonine kinase membre de la famille des"mixed-lineage kinases" (MLKs) dont la fonction est vraisemblablement associée à la régulation des processus de prolifération et de différenciation cellulaire. Dans le but d'obtenir des indices supplémentaires relativement à son rôle physiologique, l'étude de sa localisation subcellulaire a été effectuée. Ainsi, nous avons dans un premier temps, localisé la protéine kinase ZPK endogène dans les cellules NIH 3T3 au niveau de l'appareil de Golgi, suggérant alors son implication possible dans la modulation des diverses fonctions caractéristiques de cet organelle. ZPK comporte au sein de sa séquence primaire de nombreux motifs susceptibles de médier, au cours de la transduction des signaux, des interactions protéine-protéine dans le but d'assurer la propagation de l'information en direction du noyau et par le fait même d'exercer ses fonctions à travers les différents processus cellulaires. Pour vérifier d'une part, son association au niveau de l'appareil de Golgi et d'autre part, sa capacité à médier des interactions protéiques, une protéine de fusion bactérienne correspondant à l'une des régions riches en prolines de la protéine kinase ZPK a été produite. Des extraits membranaires de cellules NIH 3T3 ont été transférées sur membrane de PVDF pour être ensuite incubés avec cette sonde protéique, le contrôle négatïf étant l'utilisation de la sonde GST. Une protéine d'environ 30 kDa (P30) ayant interagit spécifiquement avec la portion proline riche de ZPK a été identifiée. Cette dernière a ensuite été purifiée par chromatographie d'affinité grâce à l'utilisation d'une matrice de glutathione sépharose complexée à la protéine de fusion ZPK. L'identification de ce partenaire n'a cependant pu être effectuée puisque le spectre de masse a révélé qu'il s'agissait d'une protéine inconnue à ce jour

The role of the MAPK pathway alterations in GM-CSF modulated human neutrophil apoptosis with aging

BACKGROUND: Neutrophils represent the first line of defence against aggressions. The programmed death of neutrophils is delayed by pro-inflammatory stimuli to ensure a proper resolution of the inflammation in time and place. The pro-inflammatory stimuli include granulocyte-macrophage colony-stimulating factor (GM-CSF). Recently, we have demonstrated that although neutrophils have an identical spontaneous apoptosis in elderly subjects compared to that in young subjects, the GM-CSF-induced delayed apoptosis is markedly diminished. The present study investigates whether an alteration of the GM-CSF stimulation of MAPKs play a role in the diminished rescue from apoptosis of PMN of elderly subjects. METHODS: Neutrophils were separated from healthy young and elderly donors satisfying the SENIEUR protocol. Neutrophils were stimulated with GM-CSF and inhibitors of the MAPKinase pathway. Apoptosis commitment, phosphorylation of signaling molecules, caspase-3 activities as well as expression of pro- and anti-apoptotic molecules were performed in this study. Data were analyzed using Student's two-tailed t-test for independent means. Significance was set for p ≤ 0.05 unless stated otherwise. RESULTS: In this paper we present evidence that an alteration in the p42/p44 MAPK activation occurs in PMN of elderly subjects under GM-CSF stimulation and this plays a role in the decreased delay of apoptosis of PMN in elderly. We also show that p38 MAPK does not play a role in GM-CSF delayed apoptosis in PMN of any age-groups, while it participates to the spontaneous apoptosis. Our results also show that the alteration of the p42/p44 MAPK activation contributes to the inability of GM-CSF to decrease the caspase-3 activation in PMN of elderly subjects. Moreover, GM-CSF converts the pro-apoptotic phenotype to an anti-apoptotic phenotype by modulating the bcl-2 family members Bax and Bcl-xL in PMN of young subjects, while this does not occur in PMN of elderly. However, this modulation seems MAPK independent. CONCLUSION: Our results show that the alteration of p42/p44 MAPK activation contributes to the GM-CSF induced decreased PMN rescue from apoptosis in elderly subjects. The modulation of MAPK activation in PMN of elderly subjects might help to restore the functionality of PMN with aging

Definition of LCA guidelines in the geothermal sector to enhance result comparability

Geothermal energy could play a crucial role in the European energy market and future scenarios focused on sustainable development. Thanks to its constant supply of concentrated energy, it can support the transition towards a low-carbon economy. In the energy sector, the decision-making process should always be supported by a holistic science-based approach to allow a comprehensive environmental assessment of the technological system, such as the life cycle assessment (LCA) methodology. In the geothermal sector, the decision-making is particularly difficult due to the large variability of reported results on environmental performance across studies. This calls for harmonized guidelines on how to conduct LCAs of geothermal systems to enhance transparency and results comparability, by ensuring consistent methodological choices and providing indications for harmonized results reporting. This work identifies the main critical aspects of performing an LCA of geothermal systems and provides solutions and technical guidance to harmonize its application. The proposed methodological approach is based on experts’ knowledge from both the geothermal and LCA sectors. The recommendations cover all the life cycle phases of geothermal energy production (i.e., construction, operation, maintenance and end of life) as well as a selection of LCA key elements thus providing a thorough base for concerted LCA guidelines for the geothermal sector. The application of such harmonized LCA framework can ensure comparability among LCA results from different geothermal systems and other renewable energy technologies

Definition of LCA guidelines in the geothermal sector to enhance result comparability

Geothermal energy could play a crucial role in the European energy market and future scenarios focused on sustainable development. Thanks to its constant supply of concentrated energy, it can support the transition towards a low-carbon economy. In the energy sector, the decision-making process should always be supported by a holistic science-based approach to allow a comprehensive environmental assessment of the technological system, such as the life cycle assessment (LCA) methodology. In the geothermal sector, the decision-making is particularly difficult due to the large variability of reported results on environmental performance across studies. This calls for harmonized guidelines on how to conduct LCAs of geothermal systems to enhance transparency and results comparability, by ensuring consistent methodological choices and providing indications for harmonized results reporting. This work identifies the main critical aspects of performing an LCA of geothermal systems and provides solutions and technical guidance to harmonize its application. The proposed methodological approach is based on experts' knowledge from both the geothermal and LCA sectors. The recommendations cover all the life cycle phases of geothermal energy production (i.e., construction, operation, maintenance and end of life) as well as a selection of LCA key elements thus providing a thorough base for concerted LCA guidelines for the geothermal sector. The application of such harmonized LCA framework can ensure comparability among LCA results from different geothermal systems and other renewable energy technologies

Knowing and being known: the qualities that make a long-term care facility a home

There has been consistent pressure to transform long-term care (LTC) facilities into more homelike settings. The concept of home within institutionalized care-based living environments is not well understood. For this study, a supplementary analysis was conducted to address two questions: (1) What factors contribute to a sense of home for people living and working in rural LTC homes, and (2) What organizational structures enable or impede a rural LTC home’s ability to actualize the factors that help them feel homelike? Findings indicate that the physical environment should prioritize accessibility and personalization; the social environment should prioritize relationships and opportunities for connection; and psychological considerations should prioritize supporting choice, autonomy, and flexibility. Additionally, a sense of home in LTC is dependent upon leadership that empowers staff and enables a flexible and relational approach to care, which results in residents being truly ‘known’ by their care providers

Nonpharmacological management of behavioral and psychological symptoms of dementia: what works, in what circumstances, and why?

Sherpa Romeo yellow journal. Open access article. Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0) appliesObjective: Behavioral and psychological symptoms of dementia (BPSD) refer to the often distressing, noncognitive symptoms of dementia. BPSD appear in up to 90% of persons with dementia and can cause serious complications. Reducing the use of antipsychotic medications to treat BPSD is an international priority. This review addresses the following questions: What nonpharmacological interventions work to manage BPSD? And, in what circumstances do they work and why? Method: A realist review was conducted to identify and explain the interactions among context, mechanism, and outcome. We searched electronic databases for empirical studies that reported a formal evaluation of nonpharmacological interventions to decrease BPSD. Results: Seventy-four articles met the inclusion criteria. Three mechanisms emerged as necessary for sustained effective outcomes: the caring environment, care skill development and maintenance, and individualization of care. We offer hypotheses about how different contexts account for the success, failure, or partial success of these mechanisms within the interventions. Discussion: Nonpharmacological interventions for BPSD should include consideration of both the physical and the social environment, ongoing education/training and support for care providers, and individualized approaches that promote self-determination and continued opportunities for meaning and purpose for persons with dementia

Insights into water coordination associated with the Cu(II)/Cu(I) electron transfer at a biomimetic Cu centre.

International audienceThe coordination properties of the biomimetic complex [Cu(TMPA)(H2O)](CF3SO3)2 (TMPA = tris(2-pyridylmethyl)amine) have been investigated by electrochemistry combined with UV-Vis and EPR spectroscopy in different non-coordinating media including imidazolium-based room-temperature ionic liquids, for different water contents. The solid-state X-ray diffraction analysis of the complex shows that the cupric centre lies in a N4O coordination environment with a nearly perfect trigonal bipyramidal geometry (TBP), the water ligand being axially coordinated to Cu(II). In solution, the coordination geometry of the complex remains TBP in all media. Neither the triflate ion nor the anions of the ionic liquids were found to coordinate the copper centre. Cyclic voltammetry in all media shows that the decoordination of the water molecule occurs upon monoelectronic reduction of the Cu(II) complex. Back-coordination of the water ligand at the cuprous state can be detected by increasing the water content and/or decreasing the timescale of the experiment. Numerical simulations of the voltammograms allow the determination of kinetics and thermodynamics for the water association-dissociation mechanism. The resulting data suggest that (i) the binding/unbinding of water at the Cu(I) redox state is relatively slow and equilibrated in all media, and (ii) the binding of water at Cu(I) is somewhat faster in the ionic liquids than in the non-coordinating solvents, while the decoordination process is weakly sensitive to the nature of the solvents. These results suggest that ionic liquids favour water exchange without interfering with the coordination sphere of the metal centre. This makes them promising media for studying host-guest reactions with biomimetic complexes

Ecotoxicity characterization of chemicals: global recommendations and implementation in USEtox

Chemicals emitted to the environment affect ecosystem health from local to global scale, and reducing chemical impacts has become an important element of European and global sustainability efforts. The present work ad-vances ecotoxicity characterization of chemicals in life cycle impact assessment by proposing recommendations resulting from international expert workshops and work conducted under the umbrella of the UNEP-SETAC Life Cycle Initiative in the GLAM project (Global guidance on environmental life cycle impact assessment indicators). We include specific recommendations for broadening the assessment scope through proposing to introduce additional environmental compartments beyond freshwater and related ecotoxicity indicators, as well as for adapting the ecotoxicity effect modelling approach to better reflect environmentally relevant exposure levels and including to a larger extent chronic test data. As result, we (1) propose a consistent mathematical framework for calculating freshwater ecotoxicity characterization factors and their underlying fate, exposure and effect pa-rameters; (2) implement the framework into the USEtox scientific consensus model; (3) calculate characteriza-tion factors for chemicals reported in an inventory of a life cycle assessment case study on rice production and consumption; and (4) investigate the influence of effect data selection criteria on resulting indicator scores. Our results highlight the need for careful interpretation of life cycle assessment impact scores in light of robustness of underlying species sensitivity distributions. Next steps are to apply the recommended characterization frame-work in additional case studies, and to adapt it to soil, sediment and the marine environment. Our framework is applicable for evaluating chemicals in life cycle assessment, chemical and environmental footprinting, chemical substitution, risk screening, chemical prioritization, and comparison with environmental sustainability targets.Environmental Biolog