Search results for "interactions."
showing 10 items of 1865 documents
Experimental evidence for a hierarchy of mate- and host-induced cues in a fish ectoparasite, Argulus coregoni (Crustacea: Branchiura)
2007
Argulus coregoni is an ectoparasite primarily infesting freshwater salmonids. Sexually reproducing parasites such as A. coregoni are confronted with a dilemma between finding a mate and the costs involved in doing so; if mating partners are unavailable on a host, by leaving to search for a mate on a new host, the parasite is exposed to risks such as predation and energy loss. The utilization of chemical cues could enhance the probability of finding a host and/or a suitable mating partner and thus decrease the level of costs associated with detachment from the host. In this study we constructed a Y-maze arena to determine if adult A. coregoni respond to mate- and host-related chemical cues. …
Mechanisms of Ca2+ liberation at fertilization
2005
The mechanisms underlying the Ca2+ release at fertilization of several animal organisms are reported. Four main classical theories are described, i.e., that of Ca2+ release following simple sperm contact and a G protein stimulation; that of simple sperm contact followed by a tyrosine kinase receptor activation; that of the necessity of introduction by sperm into the egg of molecules for Ca2+ release; and that the molecule introduced into the marine eggs for Ca2+ release is the same Ca2+. Two other mechanisms for Ca2+ release are also illustrated: that of ryanodine receptor stimulation and that of NAADP formation.
A finely tuned strategy adopted by an egg parasitoid to exploit chemical traces from host adults.
2009
SUMMARY Scelionid egg parasitoids can obtain reliable information on the presence of host eggs by discriminating host gender on the basis of chemical footprints of their co-evolved hosts, with a strong preference for the footprint left by host females. Based on the concept of dietary specialization and infochemical use in natural enemies, it could be predicted that host gender discrimination in specialist species belonging to the genus Trissolcus is further tuned to specific cues from distinctive chemical traces left by host females as a consequence of copulation and/or oviposition. To test this hypothesis we used the system Murgantia histrionica – Trissolcus brochymenae. Our results showed…
The effect of glycosylation of antigens on the antibody responses against Echinostoma caproni (Trematoda: Echinostomatidae).
2014
SUMMARYIn the present study, we analyse the effect of glycosylation inEchinostoma caproni(Trematoda: Echinostomatidae) antigens in antibody responses against the parasite in experimentally infected mice. It has been previously demonstrated that the mouse is a host of high compatibility withE. caproniand develops elevated responses of IgG, IgG1, IgG3 and IgM as a consequence of the infection, though the role of glycans in these responses remains unknown. To this purpose, the responses generated in mice against non-treated excretory/secretory antigens ofE. caproniwere compared with those observed after N-deglycosylation, O-deglycosylation and double deglycosylation of the antigens by indirect…
The EUropean Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI)
2020
Funder: FP7 Ideas: European Research Council; doi: http://dx.doi.org/10.13039/100011199; Grant(s): HEALTH-F2-2010-241909
Knowledge, stigma, health seeking behaviour and its determinants among patients with post kalaazar dermal leishmaniasis, Bihar, India
2018
Background Lesishmaniasis is a neglected tropical disease endemic in Bihar, India. Inappropriate health seeking behaviour of post kala-azar dermal leishmaniasis (PKDL) patients may increase the disease duration, severity and transmissibility. Simultaneously, lack of knowledge and perceived stigma may also increase the length of delay in receiving treatment. This ultimately effects the kala-azar elimination program. Methods A cross sectional study was conducted in 120 confirmed PKDL patients, aged 18 years and older. Data related to knowledge and health seeking behaviour was collected by a pre-tested questionnaire. EMIC stigma scale was used for assessing the perceived stigma. Patients were …
Microsporidia parasites disrupt the responses to cadmium exposure in a gammarid.
2011
7 pages; International audience; Microsporidia parasites are commonly found in amphipods, where they are often asymptomatic, vertically-transmitted and have several effects on host sexuality and behaviour. As amphipods are often used as models in ecotoxicological studies, we investigated the effect of microsporidian infections on energy reserves and defence capacities of Gammarus roeseli under cadmium stress. Only females were infected by two microsporidia parasites: Dictyocoela roeselum or Dictyocoela muelleri. In physiological conditions, microsporidia had no major effect on energy reserves and defence capacities of G. roeseli, while under cadmium exposure, energy reserves and antioxidant…
The effect of the acanthocephalan parasite Pomphorhynchus laevis on the lipid and glycogen content of its intermediate host Gammarus pulex
2001
Besides conspicuous changes in behaviour, manipulative parasites may also induce subtle physiological effects in the host that may also be favourable to the parasite. In particular, parasites may be able to influence the re-allocation of resources in their own favour. We studied the association between the presence of the acanthocephalan parasite, Pomphorhynchus laevis, and inter-individual variation in the lipid and glycogen content of its crustacean host, Gammarus pulex (Amphipoda). Infected gravid females had significantly lower lipid contents than uninfected females, but there was no difference in the lipid contents of non-gravid females and males that were infected with P. laevis. In c…
Involvement of K+ channels in the relaxant effects of YC-1 in vascular smooth muscle
1999
This study addresses the question whether K(+) channels are involved in the vasorelaxant effects of 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl-indazole (YC-1 ). In rat aorta, guinea pig aorta, and guinea pig a. carotis, YC-1 inhibited contractions induced by phenylephrine (3 microM) more potently than those induced by K(+)(48 mM). In rat aorta, tetraethylammonium (10 mM), charybdotoxin (0.2 microM), and iberiotoxin (0.1 microM), but not glibenclamide (10 microM), attenuated the relaxant effects of YC-1. In guinea pig a. carotis, YC-1 (30 microM) induced a hyperpolarisation which was antagonised by 1H-[1,2,4]oxadiazolo[4, 3-a]quinoxalin-1-one (ODQ; 50 microM). In rat aorta, YC-1 (30 microM) incr…
Neuroprotective effect of ceftriaxone on the penumbra in a rat venous ischemia model.
2012
Glutamate transporter-1 (GLT-1) maintains low concentrations of extracellular glutamate by removing glutamate from the extracellular space. It is controversial, however, whether upregulation of GLT-1 is neuroprotective under all ischemic/hypoxic conditions. Recently, a neuroprotective effect of preconditioning with a β-lactam antibiotic ceftriaxone (CTX) that increases expression of GLT-1 has been reported in animal models of focal ischemia. On the other hand, it is said that CTX does not play a neuroprotective role in an in vitro study. Thus, we examined the effect of CTX on ischemic injury in a rat model of two-vein occlusion (2VO). This model mimics venous ischemia during, e.g. tumor sur…