Dynamique spatio-temporelle des populations de truites en milieu naturel et au voisinage des ouvrages hydroélectriques

Brown trout (Salmo trutta) ecology was largely studied. However, the process structuring the spatiotemporal patterns of population dynamics remains unclear. The objective of this thesis was to identify the demographic processes (e.g. survival or displacements) and the influence of biotic (between-individuals interactions) and abiotic (environmental conditions) processes structuring the age-stages (fry, juveniles and adults) of these populations in time and space.I studied (1) the role of density-dependence on survival and (2) the influence of environmental conditions experienced by trouts (hydraulics and water temperature). To assess the results’ transferability, I studied (3) the spatial scale (global or local) of influence of the processes and (4) if those processes varied among populations (hierarchical approach).I considered the dynamics of 45 trout populations, 22 being located downstream a hydropower facility. At a large scale, the recruitment of distant populations (up to 75 km apart) may be synchronized by large floods during emergence of fry or by spawning substratum displacements. We summarized the results of a determinist population dynamics models, locally calibrated on nine reaches showing well-described environmental conditions. This summary revealed the influence of various local drivers on population dynamics. Finally, a hierarchical model showed that density-dependent mortality among juveniles and adults was a key biotic process. The strength of the competition was greater in absence of shelter (<2% of the surface) and varied with water temperature (decreasing for juveniles and increasing for adults).The results of this work will provide scientific basis to hydropower facility managers. This will help them to reduce their influence on trout populations and respond to regulatory demandsBien que l’écologie de la truite (Salmo trutta) ait déjà été bien étudiée, les processus expliquant la dynamique spatio-temporelle des populations restent à caractériser. L’objectif de cette thèse était d’identifier les processus démographiques (ex. survie ou déplacements) et l’influence des processus biotiques (interactions entre individus) et abiotiques (conditions environnementales) qui structurent dans le temps et dans l’espace les différentes classes d’âge (alevins, juvéniles et adultes) de ces populations. J’ai étudié l’influence sur la survie apparente de (1) la densité-dépendance et (2) des conditions environnementales vécues directement par les truites (habitat hydraulique et température de l’eau). Pour évaluer la transférabilité des résultats, j’ai évalué (3) l’échelle spatiale (globale ou locale) à laquelle opéraient les processus et (4) si ces processus variaient entre populations (approche hiérarchique). J’ai considéré la dynamique de 45 populations de truites dont 22 sont situées à l’aval d’un ouvrage hydroélectrique. A large échelle, il est apparu que le recrutement de populations séparées par des distances allant jusqu’à 75km peut être synchronisé par de fortes crues lors de l’émergence des alevins ou des déplacements du substrat de ponte. Nous avons synthétisé les résultats de l’application d’un modèle déterministe de dynamique de population, calibrés localement sur neuf stations aux conditions environnementales bien caractérisées. Cette synthèse a montré que des processus locaux influençaient directement la dynamique des populations. Enfin, la construction d’un modèle hiérarchique a montré le rôle structurant de la mortalité densité-dépendante des juvéniles et des adultes, dont l’intensité augmentait en l’absence d’abris (<2% de la surface) ou variait avec la température de l’eau (diminution pour les juvéniles et augmentation pour les adultes). Ce travail fournit des bases scientifiques aux gestionnaires d’ouvrages hydro-électriques pour leur permettre de limiter leur influence sur les populations de poissons et répondre ainsi aux demandes réglementaire

Tumor cell invasion of model 3‐dimensional matrices: demonstration of migratory pathways, collagen disruption, and intercellular cooperation

We report a novel 3‐dimensional model for visualizing tumor cell migration across a nylon mesh‐supported gelatin matrix. To visualize migration across these model barriers, cell proteolytic activity of the pericellular matrix was detected using Bodipy‐BSA (fluorescent upon proteolysis) and DQ™ collagen (fluorescent upon collagenase activity). For 3‐dimensional image reconstruction, multiple optical images at sequential z axis positions were deconvoluted by computer analysis. Specificity was indicated using well‐known inhibitors. Using these fluorescent proteolysis markers and imaging methods, we have directly demonstrated proteolytic and collagenolytic activity during tumor cell invasion. Moreover, it is possible to visualize migratory pathways followed by tumor cells during matrix invasion. Using cells of differing invasive potentials (uPAR‐negative T‐47D wild‐type and uPAR‐positive T‐47D A2–1 cells), we show that the presence of the T‐47D‐A2–1 cells facilitates the entry of T‐47D wild‐type cells into the matrix. In some cases, wild‐type cells follow T‐47D A2–1 cells into the matrix whereas other T‐47D‐wild‐type cells appear to enter without the direct intervention of T‐47D A2–1 cells. Thus, we have developed a new 3‐dimensional model of tumor cell invasion, demonstrated protein and collagen disruption, mapped the pathways followed by tumor cells during migration through an extracellular matrix, and illustrated cross‐talk among tumor cell populations during invasion.—Horino, K., Kindezelskii, A. L., Elner, V. M., Hughes, B. A., Petty, H. R. Tumor cell invasion of model 3‐dimensional matrices: demonstration of migratory pathways, collagen disruption, and intercellular cooperation. FASEB J. 15, 932–939 (2001)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154275/1/fsb2fj000392com.pd

Secondary Bilateral Angle Closure Glaucoma due to Topiramate

We examined a 39-year-old female with severe headache and blurred vision. She was on topiramate, 50 mg once a day for one week because of migraine. Periorbital edema, chemosis, myopia, high intraocular pressures, and shallow anterior chambers were present at the initial examination. Iridocorneal angles were closed, ultrasound showed choroidal effusions. We stopped topiramate and started antiglaucoma treatment. After one week the intraocular pressure was 10 mm Hg in both eyes without treatment. A new ultrasound showed no choroidal effusions. Topiramate has been associated with acute secondary angle closure glaucoma as an idiosyncratic reaction to the drug. Physicians prescribing topiramate need to alert patients of this potential sight-threatening idiosyncratic reaction

Influence of discharge, hydraulics, water temperature, and dispersal on density synchrony in brown trout populations (Salmo trutta)

International audienceLes facteurs environnementaux peuvent causer des fluctuations synchrones de densités entre populations. Une meilleure compréhension des processus expliquant la synchronie est fondamentale pour prédire des pertes de résilience des métapopulations sujettes à des changements environnementaux. Nous étudions la synchronie des chroniques de densités de trois classes d’âge de la truite brune (Salmo trutta) (0+, 1+ et adultes) entre 36 tronçons de cours d’eau. Nous utilisons des tests de Mantel pour discriminer les effets relatifs de la proximité géographique, de la synchronie de variables environnementales clefs (débit, température de l’eau, conditions hydrauliques et mobilité du substrat) et de la dispersion densité-dépendante. La synchronie environnementale expliquait fortement la synchronie de la truite jusqu’à des distances de 75 km. Cet effet était dû en partie à l’influence négative sur les 0+ des hauts débits pendant l’émergence et une influence de la mobilité du substrat pendant la période de ponte. La dispersion entre tronçon influençait faiblement nos résultats. Les densités de juvéniles et d’adultes étaient fortement structurées par des processus de survie, mais n’étaient pas influencées par la synchronie des conditions environnementales. Les résultats suggèrent que l’environnement peut avoir des effets généraux sur la dynamique de population qui peuvent influencer la résilience des métapopulation

Toll-Like Receptor 4 (TLR4) of Retinal Pigment Epithelial Cells Participates in Transmembrane Signaling in Response to Photoreceptor Outer Segments

Retinal pigment epithelial (RPE) cells mediate the recognition and clearance of effete photoreceptor outer segments (POS), a process central to the maintenance of normal vision. Given the emerging importance of Toll-like receptors (TLRs) in transmembrane signaling in response to invading pathogens as well as endogenous substances, we hypothesized that TLRs are associated with RPE cell management of POS. TLR4 clusters on human RPE cells in response to human, but not bovine, POS. However, TLR4 clustering could be inhibited by saturating concentrations of an inhibitory anti-TLR4 mAb. Furthermore, human POS binding to human RPE cells elicited transmembrane metabolic and calcium signals within RPE cells, which could be blocked by saturating doses of an inhibitory anti-TLR4 mAb. However, the heterologous combination of bovine POS and human RPE did not trigger these signals. The pattern recognition receptor CD36 collected at the POS–RPE cell interface for both homologous and heterologous samples, but human TLR4 only collected at the human POS–human RPE cell interface. Kinetic experiments of human POS binding to human RPE cells revealed that CD36 arrives at the POS–RPE interface followed by TLR4 accumulation within 2 min. Metabolic and calcium signals immediately follow. Similarly, the production of reactive oxygen metabolites (ROMs) was observed for the homologous human system, but not the heterologous bovine POS–human RPE cell system. As (a) the bovine POS/human RPE combination did not elicit TLR4 accumulation, RPE signaling, or ROM release, (b) TLR4 arrives at the POS–RPE cell interface just before signaling, (c) TLR4 blockade with an inhibitory anti-TLR4 mAb inhibited TLR4 clustering, signaling, and ROM release in the human POS–human RPE system, and (d) TLR4 demonstrates similar clustering and signaling responses to POS in confluent RPE monolayers, we suggest that TLR4 of RPE cells participates in transmembrane signaling events that contribute to the management of human POS

Physio-Stacks: Supporting Communication with Ourselves and Others via Tangible, Modular Physiological Devices

International audienceOur physiological activity reflects our inner workings. However, we are not always aware of it in full detail. Physiological devices allow us to monitor and create adaptive systems and support introspection. Given that these devices have access to sensitive data, it is vital that users have a clear understanding of the internal mechanisms (extrospection), yet the underlying processes are hard to understand and control, resulting in a loss of agency. In this work, we focus on bringing the agency back to the user, by using design guidelines based on principles of honest communication and driven by positive activities. To this end, we conceived a tangible, modular approach for the construction of physiological interfaces that can be used as a prototyping toolkit by designers and researchers, or as didactic tools by educators and pupils. We show the potential of such an approach with a set of examples, supporting introspection, dialog, music creation, and play

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery