Search results for "Tau"
showing 10 items of 4585 documents
Cold water reduces the severity of parasite-inflicted damage : support for wintertime recuperation in aquatic hosts
2019
The reduction in host fitness caused by parasite infections (virulence) depends on infection intensity and the degree of damage caused per parasite. Environmental conditions can shape both virulence components, but in contrast to infection intensity, environmental impacts on per-parasite damage are poorly understood. Here, we studied the effect of ambient temperature on per-parasite damage, which is jointly determined by the ability of parasites to induce harm (per-parasite pathogenicity) and the ability of hosts to limit damage (tolerance). We experimentally exposed two salmonid species, Atlantic salmon (Salmo salar) and sea trout (Salmo trutta), to replicated genotypes of the eye fluke Di…
Increasing temperatures accentuate negative fitness consequences of a marine parasite
2020
AbstractInfectious diseases are key drivers of wildlife populations and agriculture production, but whether and how climate change will influence disease impacts remains controversial. One of the critical knowledge gaps that prevents resolution of this controversy is a lack of high-quality experimental data, especially in marine systems of significant ecological and economic consequence. Here, we performed a manipulative experiment in which we tested the temperature-dependent effects on Atlantic salmon (Salmo salar) of sea lice (Lepeophtheirus salmonis)—a parasite that can depress the productivity of wild-salmon populations and the profits of the salmon-farming industry. We explored sea-lou…
Intégrer la connectivité paysagère dans la séquence ERC : une approche par la quantité d'habitat atteignable
2019
Des engagements nationaux, européens et internationaux ont été pris pour maintenir et restaurer la connectivité entre habitats naturels face à la perte et à la fragmentation de ces habitats. Dans le même temps, les politiques environnementales dans différents pays mettent en oeuvre la séquence Eviter-Réduire-Compenser (ERC) pour atteindre l’objectif d’absence de perte nette de biodiversité (PPN). La séquence ERC a pour principe d’évaluer l’ensemble des impacts écologiques d’un aménagement, mais les critères et indicateurs permettant de quantifier les impacts sur la connectivité paysagère ne sont pas satisfaisants. Nous proposons une démarche opérationnelle pour évaluer les impacts environne…
The effects of different combinations of fixed and moving bed bioreactors on rainbow trout (Oncorhynchus mykiss) growth and health, water quality and…
2019
Abstract The effect of bioreactor design on nitrification efficiency has been well studied, but less is known about the overall impacts on water quality. Besides nitrification, submerged fixed bed bioreactors (FBBR) trap fine solid particles, whereas moving bed bioreactors (MBBR) grind solids, possibly increasing solids and particle accumulation in the system. In this experiment, the effects of different combinations of fixed bed and moving bed bioreactors on water quality, solids removal, particle size distribution, fish health based on histopathological changes and nitrification efficiency were studied in laboratory scale recirculating aquaculture systems (RAS) with rainbow trout (Oncorhy…
<em>Centaurea inexpugnabilis</em>, una nueva especie de la sección <em>Acrocentron</em> para la flora ibérica
2017
Se describe una nueva especie para el género Centaurea L. (sect. Acrocentron, Asteraceae): C. inexpugnabilis, sp. nov. Esta planta ha sido localizada al pie de los Mallos de Riglos (Riglos, Huesca) y su distribución se circunscribe por el momento al cuadrante nororiental de la península ibérica. Junto a su descripción y diagnosis, se aporta una lámina y varias tablas con los principales caracteres diagnósticos que la diferencian de las especies más próximas.
Effect of resource availability on evolution of virulence and competition in an environmentally transmitted pathogen
2018
Understanding ecological and epidemiological factors driving pathogen evolution in contemporary time scales is a major challenge in modern health management. Pathogens that replicate outside the hosts are subject to selection imposed by ambient environmental conditions. Increased nutrient levels could increase pathogen virulence by pre-adapting for efficient use of resources upon contact to a nutrient rich host or by favouring transmission of fast-growing virulent strains. We measured changes in virulence and competition in Flavobacterium columnare, a bacterial pathogen of freshwater fish, under high and low nutrient levels. To test competition between strains in genotype mixtures, we devel…
The Role of Chemokines in Alzheimer's Disease
2019
Objective: The most common multifactorial neurodegenerative disorder occurring in old age is Alzheimer’s disease. The neuropathological hallmarks of that disorder are amyloid plaques with the presence of β -amyloid aggregates, intraneuronal tau protein tangles, and chronic inflammation. Brain cells such as microglia and astrocytes are inflammatory cells associated with Alzheimer’s disease and involved in the production of inflammatory mediators, such as cytokines and chemokines. Chemokines consist of a large family of protein mediators with low molecular weight, which able to control the migration and residence of all immune cells. In pathological conditions, such as Alzheimer’s disease, c…
Taurine potentiates the anticonvulsive effect of the GABAAagonist muscimol and pentobarbital in the immature mouse hippocampus
2019
Objective The high incidence of epileptic seizures in neonates and their frequent refractoriness to pharmacologic therapies require identification of new therapeutical options. Therefore, we investigated whether the modulatory effect of taurine on γ-aminobutyric acid (GABA)A receptors can enhance the anticonvulsive potential of the GABAA receptor agonist muscimol and of the barbiturate pentobarbital. Methods We performed field potential recordings in in toto hippocampus preparations of immature (postnatal days 4-7) C57Bl/6 mouse pups. Spontaneous epileptiform activity was induced by the continuous presence of the potassium channel blocker 4-aminopyridine and the glycinergic antagonist stryc…
Epilepsy in neuropathologically verified Alzheimer's disease.
2018
Abstract Purpose Subjects with Alzheimer's disease (AD) have been shown to be at a higher risk for epilepsy. The vast majority of the previous studies have not included a full neuropathological examination. Methods The objective of this study was to assess the prevalence of epilepsy and clinicopathological characteristics in a well-defined study group of 64 subjects with AD. We evaluated the clinicopathological findings in 64 subjects (mean age at death 85 ± 8.6 years) from a longitudi-nal study cohort of patients with dementia. Results Eleven out of the 64 subjects (17%) had a history of epilepsy, which is comparable to previous studies. The subjects with AD and epilepsy were significantly…
Insulin resistance is associated with altered amino acid metabolism and adipose tissue dysfunction in normoglycemic women
2016
AbstractInsulin resistance is associated adiposity, but the mechanisms are not fully understood. In this study, we aimed to identify early metabolic alterations associated with insulin resistance in normoglycemic women with varying degree of adiposity. One-hundred and ten young and middle-aged women were divided into low and high IR groups based on their median HOMA-IR (0.9 ± 0.4 vs. 2.8 ± 1.2). Body composition was assessed using DXA, skeletal muscle and liver fat by proton magnetic resonance spectroscopy, serum metabolites by nuclear magnetic resonance spectroscopy and adipose tissue and skeletal muscle gene expression by microarrays. High HOMA-IR subjects had higher serum branched-chain …