Non-surgical transplantation of Oesophagostomum dentatum to recipient pigs via rectal intubation

Construction of gender-enriched cDNA archives for adult Oesophagostomum dentatum by suppressive-subtractive hybridization and a microarray analysis of expressed sequence tags

“…Given the gene silencing phenotype of cgh-1 in C. elegans (see Navarro et al 2001), it would be informative to perform RNAi studies of fourthstage larvae of O. dentatum, to transplant them into a naïve host (e.g. via rectal intubation ; see Christensen et al 1996) and to subsequently monitor the reproductive potential of treated worms in vivo. Understanding the function of this (cgh-1) and related genes and gene products, which are involved in fundamental aspects of nematode biology could be important in the discovery of drugs against parasites (cf .…”

“…Nonetheless, given the recent progress and successes in the application of RNAi to parasitic nematodes (Aboobaker and Blaxter, 2004), particularly the development of an effective RNAi approach for T. colubriformis (utilizing an electroporation step to transfer dsRNA into the larval stage of the nematode) (Issa et al 2005), there is considerable prospect for an RNAi assay for Oesophostomum dentatum, provided that this nematode has the appropriate ' RNAi machinery ' (van Roessel and Brand, 2004). The attributes of O. dentatum, including a short life-cycle (usually y21-25 days ; Talvik et al 1997), the production of large numbers of progeny, the availability of a non-surgical transplantation procedure (Christensen et al 1996) to manipulate, for example, the ratio of male and female parasites or the number of worms per host individual (intensity of infection) and the ability to maintain the parasite in culture in vitro for 28 days (Daugschies and Watzel, 1999), indicate that this system will be particularly useful for testing (both in vitro and in vivo) the functional roles of gender-specific genes represented in the EST archives constructed herein. Future investigations will focus on isolating and characterizing selected genes.…”

Experimental hybridization between Oesophagostomum dentatum and O . quadrispinulatum in pigs

“…Transfer of worms from one host to another was accomplished using a nonsurgical transplantation technique (Christensen et al 1996b), whereby worms are inserted via a polyvinylchloride (PVC) tube approximately 30±50 cm into the rectum/colon descendens, from which point the worms migrate, and 60±70% of them may establish in their predilection site in the anterior and intermediate portion of the colon (Christensen et al 1996b). This method was initially established with adult worms; however, we desired to use 10-day-old fourth-stage larvae (L 4 ), and that approach was validated in a pilot experiment demonstrating the establishment of 35± 44% of the transplanted larvae.…”

“…This system provides the basis for a range of studies on the dynamics of infections and the development of drug resistance as well as genetic structures in parasite populations. Recently, a novel nonsurgical procedure (Christensen et al 1996b) has been developed for the transplantation of adult worms (single sex or mixed sexes) from one host to another, which provides a unique opportunity to study various aspects relating to mating behavior and inheritance in parasitic nematodes.…”

“…Transfer protocol of 3 attempts at experimental hybridization of Oesophagostomum dentatum with O. quadrispinulatum using adult worms in experiment 1 or 10-day-old L 4 in experiments 2 and 3 a (Od O. dentatum, Oq O. quadrispinulatum) a A nonsurgical rectal transplantation technique was used(Christensen et al 1996b) …”