TRPV1 dysfunction in cystinosis patients harboring the homozygous 57 kb deletion.

Cystinosis is a rare autosomal recessive disorder characterized by lysosomal cystine accumulation due to loss of function of the lysosomal cystine transporter (CTNS). The most common mutation in cystinosis patients of Northern Europe consists of a 57-kb deletion. This deletion not only inactivates the CTNS gene but also extends into the non-coding region upstream of the start codon of the TRPV1 gene, encoding the capsaicin- and heat-sensitive ion channel TRPV1. To evaluate the consequences of the 57-kb deletion on functional TRPV1 expression, we compared thermal, mechanical and chemical sensitivity of cystinosis patients with matched healthy controls. Whereas patients heterozygous for the 57-kb deletion showed normal sensory responses, homozygous subjects exhibited a 60% reduction in vasodilation and pain evoked by capsaicin, as well as an increase in heat detection threshold. Responses to cold, mechanical stimuli or cinnamaldehyde, an agonist of the related nociceptor channel TRPA1, were unaltered. We conclude that cystinosis patients homozygous for the 57-kb deletion exhibit a strong reduction of TRPV1 function, leading to sensory deficiencies akin to the phenotype of TRPV1-deficient mice. These deficits may account for the reported sensory alterations and thermoregulatory deficits in these patients, and provide a paradigm for life-long TRPV1 deficiency in humans.

Parasitation of the parasitic wasp Ephedrus Persicae(Frogatt) on the rosy apple aphid Dysaphis Plantaginea (Passerini).

The rosy apple aphid Dysaphis plantaginea is one of the most important leaf sucking pests in pome fruit. As damage, caused by an infestation of a relatively small number of fundatrices in spring, easily exceeds the economic threshold level, pest management is crucial. Besides the use of IPM-compatible pesticides, natural enemies (ladybird beetles, parasitic wasps, saw flies...) can play an additional role in controlling aphids. In Europe, the solitary endoparasitoid Ephedrus persicae (Hymenoptera: Braconidae, Aphidiinae) is the dominant parasitic wasp attacking rosy apple aphid. As this parasitoid develops later than its host, control is determined by the population density and the parasitising efficiency of the wasp. The population increase within a season is determined by generation turnover and parasitizing capacity, a factor poorly understood in E. persicae. To be able to estimate the number of wasps required for successful control the parasitic behaviour was studied in semi-field circumstances. Artificially infested colonies of rosy apple aphid on apple trees grown in a greenhouse, were covered with cages of gauze in which young, mated female parasitic wasps were released. The number of aphids (alatae, apterae and mummies) as well as the number of adult parasitic wasps were recorded weekly until the end of infestation or parasitation. This test method allowed a comparison of the parasitizing efficacy of Ephedrus with that of the well-studied parasitoid Aphelinus mali (Haldeman), that efficiently controls the woolly aphid Eriosoma lanigerum (Hausmann).