Search results for "mediat"

2021

Social insects are hosts of diverse parasites, but the influence of these parasites on phenotypic host traits is not yet well understood. Here, we tracked the survival of tapeworm-infected ant workers, their uninfected nest-mates and of ants from unparasitized colonies. Our multi-year study on the ant Temnothorax nylanderi, the intermediate host of the tapeworm Anomotaenia brevis, revealed a prolonged lifespan of infected workers compared with their uninfected peers. Intriguingly, their survival over 3 years did not differ from those of (uninfected) queens, whose lifespan can reach two decades. By contrast, uninfected workers from parasitized colonies suffered from increased mortality comp…

Differential influence of Pomphorhynchus laevis (Acanthocephala) on the behaviour of native and invader gammarid species

2000

Although various species of acanthocephalan parasites can increase the vulnerability of their amphipod intermediate hosts to predation, particularly by altering their photophobic behaviour, their influence on the structure of amphipod communities and the success of invader species has so far received little attention. We compared the prevalence and behavioural influence of a fish acanthocephalan parasite, Pomphorhynchus laevis, in two species of amphipods, Gammarus pulex and Gammarus roeseli in sympatry in the river Ouche (Burgundy, eastern France). There, G. pulex is a resident species, whereas G. roeseli is a recent coloniser. Both uninfected G. pulex and G. roeseli were strongly photopho…

Bird and amphipod parasites illustrate a gradient from adaptation to exaptation in complex life cycle.

2010

6 pages; International audience; Trophically transmitted parasites modify the phenotype of their hosts, sometimes in a way that facilitates transmission. Parasite-induced changes can be either part of a manipulative strategy evolved to improve the transmission success of the parasite, or simply by-products of infection with no health effect. In the former case, manipulation is regarded as a parasite adaptation driven by the probability of being eaten by a suitable next host. Here, we consider the fact that manipulation may also be an 'exaptation': a trait that evolved for a certain use, but which has been co-opted for a new use. According to this view, features built by natural selection fo…

Characterization of the biodegradation, bioremediation and detoxification capacity of a bacterial consortium able to degrade the fungicide thiabendaz…

2017

Thiabendazole (TBZ) is a persistent fungicide used in the post-harvest treatment of fruits. Its application results in the production of contaminated effluents which should be treated before their environmental discharge. In the absence of efficient treatment methods in place, biological systems based on microbial inocula with specialized degrading capacities against TBZ could be a feasible treatment approach. Only recently the first bacterial consortium able to rapidly transform TBZ was isolated. This study aimed to characterize its biodegradation, bioremediation and detoxification potential. The capacity of the consortium to mineralize 14C-benzyl-ring labelled TBZ was initially assessed. …

Parasite-induced suppression of aggregation under predation risk in a freshwater amphipod

2012

a b s t r a c t Recent findings suggest that grouping with conspecifics is part of the behavioural defences developed by amphipod crustaceans to face predation risk by fish. Amphipods commonly serve as intermediate hosts for trophically transmitted parasites. These parasites are known for their ability to alter intermediate host phenotype in a way that promotes predation by definitive hosts, where they reproduce. If aggregation in amphipods dilutes the risk to be preyed on by fish, then it may dilute the probability of transmission for the parasite using fish as definitive hosts. Using experimental infections, we tested whether infection with the fish acanthocephalan Pomphorhynchus laevis a…

Nitric Oxide Signalling in Plants: Cross-Talk With Ca2+, Protein Kinases and Reactive Oxygen Species

2010

International audience; Nitric oxide (NO) is a gaseous free radical recognized as a ubiquitous signal transducer that contributes to various biological processes in animals. It exerts most of its effects by regulating the activities of various proteins including Ca2+ channels, protein kinases and transcription factors. In plants, studies conducted over the past ten years revealed that NO also functions as an endogenous mediator in diverse physiological processes ranging from root development to stomatal closure. Its biological role as an intracellular plant messenger molecule, however, remains poorly understood. Here, we review the molecular basis of NO signaling in animals and discuss curr…

Costs and Benefits of Experimentally Induced Changes in the Allocation of Growth versus Immune Function under Differential Exposure to Ectoparasites

2010

Background Ecological immunology has focused on the costs of investment in immunocompetence. However, understanding optimal resource allocation to immune defence requires also identification of its benefits, which are likely to occur only when parasites are abundant. Methodology We manipulated the abundance of parasitic hen fleas in blue tit (Cyanistes caeruleus) nests, and supplemented their hosts, the nestlings, with methionine (a sulphur amino acid enhancing cell-mediated immunity) during day 3–6. We found a significant interaction between these two experimental factors on the development of immune defences and growth rates. Only in parasitized nests did methionine supplementation boost …

From Neo-Functional Peace to a Logic of Spillover in EU External Policy: A Response to Visoka and Doyle

2017

In their recently published JCMS article, Gezim Visoka and John Doyle have proposed the concept of ‘neofunctional peace’ as a means to conceptualize the EU's peacemaking practices in the case of the EU-facilitated Belgrade-Pristina dialogue. This article challenges the ‘neo-functional peace’ on conceptual and empirical grounds. We critically discuss Visoka and Doyle's (2016) reading of neofunctionalism and question parts of their empirical evidence given for the existence of a ‘neo-functional peace’. Going beyond a mere critique of the article by Visoka and Doyle and arguing that the authors may not have fully exploited neofunctionalism's potential for theorizing EU external policy, we stip…

Successful aerobic bioremediation of groundwater contaminated with higher chlorinated phenols by indigenous degrader bacteria

2018

The xenobiotic priority pollutant pentachlorophenol has been used as a timber preservative in a polychlorophenol bulk synthesis product containing also tetrachlorophenol and trichlorophenol. Highly soluble chlorophenol salts have leaked into groundwater, causing severe contamination of large aquifers. Natural attenuation of higher-chlorinated phenols (HCPs: pentachlorophenol + tetrachlorophenol) at historically polluted sites has been inefficient, but a 4-year full scale in situ biostimulation of a chlorophenol-contaminated aquifer by circulation and re-infiltration of aerated groundwater was remarkably successful: pentachlorophenol decreased from 400 μg L−1 to <1 μg L−1 and tetrachlorophen…

What is the impact of a novel MED12 variant on syndromic conotruncal heart defects? Analysis of case report on two male sibs

2020

Abstract Background Syndromic congenital heart disease accounts for 30% of cases and can be determined by genetic, environmental or multifactorial causes. In many cases the etiology remains uncertain. Many known genes are responsible for specific morphopathogenetic mechanisms during the development of the heart whose alteration can determine specific phenotypes of cardiac malformations. Case presentation We report on two cases of association of conotruncal heart defect with facial dysmorphisms in sibs. In both cases the malformations’ identification occurred by ultrasound in the prenatal period. It was followed by prenatal invasive diagnosis. The genetic analysis revealed no rearrangements …