102 research outputs found

    Index de la chronique bibliographique

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    Foram analisados a relação peso-comprimento e o fator de condição de Astyanax intermedius parasitados ou não pelo isópode Paracymothoa astyanaxi. A relação peso-comprimento foi estimada para fêmeas, machos e imaturos, e sazonalmente tanto para os peixes quanto para o parasito, por meio da expressão P = aCb. O fator de condição dos exemplares não parasitados diferiu sazonalmente e entre os sexos, contrastando com os valores do fator de condição dos peixes parasitados, que não apresentaram diferenças sazonais e entre os sexos. O fator de condição dos exemplares não parasitados foi sempre maior do que o dos exemplares parasitados. Os exemplares de Astyanax intermedius parasitados não passaram pelas mesmas condições bióticas dos indivíduos não parasitados, apresentando um fator de condição semelhante ao longo do ano. Conclui-se que o parasitismo por P. astyanaxi atua de forma deletéria na população desse hospedeiro, podendo causar alterações nas dinâmicas reprodutiva e alimentar dos exemplares parasitados em razão da baixa condição corpórea.In this work the length-weight relationship and the condition factor of Astyanax intermedius parasitised and not by Paracymothoa astyanaxi were analysed in the Grande River. The length-weight relationship was estimated for females, males and immatures, and seasonally for the fishes and the parasites through the expression W = aLb. The condition factor of non-parasitised specimens differed seasonally and between sexes, contrasting with the results for parasitised fishes which showed no differences between sexes and season. The condition factor of non-parasitised specimens was higher than that of the parasitised fishes. Specimens of Astyanax intermedius parasitised do not have the same biotic conditions compared to non-parasitised individuals, in which the condition factor was similar over the years. In conclusion, parasitism by P. astyanaxi has deleterious effects on this host population which may cause changes in the reproductive and food dynamics of parasitised specimens due to low body conditions

    On the genetic involvement of apoptosis-related genes in Crohn's disease as revealed by an extended association screen using 245 markers: no evidence for new predisposing factors

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    Crohn's disease (CD) presents as an inflammatory barrier disease with characteristic destructive processes in the intestinal wall. Although the pathomechanisms of CD are still not exactly understood, there is evidence that, in addition to e.g. bacterial colonisation, genetic predisposition contributes to the development of CD. In order to search for predisposing genetic factors we scrutinised 245 microsatellite markers in a population-based linkage mapping study. These microsatellites cover gene loci the encoded protein of which take part in the regulation of apoptosis and (innate) immune processes. Respective loci contribute to the activation/suppression of apoptosis, are involved in signal transduction and cell cycle regulators or they belong to the tumor necrosis factor superfamily, caspase related genes or the BCL2 family. Furthermore, several cytokines as well as chemokines were included. The approach is based on three steps: analyzing pooled DNAs of patients and controls, verification of significantly differing microsatellite markers by genotyping individual DNA samples and, finally, additional reinvestigation of the respective gene in the region covered by the associated microsatellite by analysing single-nucleotide polymorphisms (SNPs). Using this step-wise process we were unable to demonstrate evidence for genetic predisposition of the chosen apoptosis- and immunity-related genes with respect to susceptibility for CD
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