All values were corrected by subtracting the background signal control and normalized within each trial to trophozoite lysate activity. At least four independent trials were performed for each time point. For assays using n and t butanol, each was added prior to further info addition of trophozoite lysate to a final concentration of 0. 6%. n or t butanol was also added to the negative controls to measure background. Three independent trials were per formed and each assay normalized to an untreated con trol, to which no alcohol was added. Mean values and standard deviation are shown. The effect of PLD inhibition on encystation was mea sured by addition of sterile 0. 6% n or t butanol to the encystation media at the initiation of encystation. Encystation was assayed by parasite survival in 0.

1% sarkosyl at 48 h as previously described, and normalized within each trial to the untreated sample. Three independent trials Inhibitors,Modulators,Libraries were per formed. Mean values and standard deviation are shown. P value was calculated using Students t test. Background Resistance to broad spectrum anthelmintic drugs is now widespread in parasites of domestic livestock and there are increasing concerns about the sustain ability of human parasite control programs using mass administration of the same drugs. Consequently, there is an urgent need to understand the genetic mechanisms underlying anthelmintic resistance and to discover new methods of chemical and non chemical Inhibitors,Modulators,Libraries control. However, the genomic and genetic resources required to underpin research in parasitic nematodes are lacking.

The free living nematode Caenorhabdi tis elegans is a powerful Inhibitors,Modulators,Libraries model system, but it has clear limitations for the study of parasitic species. Although the need to develop workable parasitic nematode model systems is widely recognized, most human helminth species are not amenable to experimental study. In con trast, Haemonchus contortus, a gastrointestinal parasitic nematode of small ruminants, has a successful track record in anthelmintic resistance, drug discovery and vaccine research. It is amongst the most experimentally tractable parasites for a number of reasons adult females are relatively large and produce thousands of eggs per day, allowing the production of large amounts of biological and genetic Inhibitors,Modulators,Libraries material, the infective larvae can be viably cryopreserved, and in vivo studies, including genetic crosses, can be undertaken in the natural host.

Its phylogenetic position within the most closely related group of parasites to C. elegans facilitates comparative genomics and heterologous gene expression, allowing functional studies to be performed on H. contortus genes and regulatory elements. As this parasite is a stron gylid nematode, research on it is of particular relevance to the most economically significant parasites of grazing Inhibitors,Modulators,Libraries but ruminants and to the human hookworms. H.