The major pseudocoelomic proteins of the giant kidney worm Dioctophyme renale

NAHILI GIORELLO; FRANCHINI, GISELA R.; KENNEDY, MALCOLM; BETINA CÓRSICO

Congreso; Molecular and Cellular Biology of Helminths; 2019

The giant kidney worm, Dioctophyme renale, is a member of Dioctophymatida, an order placed in Clade I (Dorylaimia) alongside Trichocephalida pathogens such as Trichuris, Trichinella, and Capillaria. Trichocephalid parasites are small and functional analysis of their proteins is difficult without resorting to recombinant methods. In contrast, D. renale is a very large nematode and thus amenable to direct biochemical investigation. D. renale is circumglobally distributed, mainly in dogs, and is increasingly regarded as a threat to wildlife, domestic animals, and humans. It infects and destroys typically the host?s right kidney, but is also found in ectopic sites. We are investigating the soluble proteins of body wall, intestine, gonads and pseudocelomic fluid (PCF) of adult D. renale to better understand its adaptations to tissue parasitism. We have focussed on two dominant proteins in D. renale PCF: P17 (17 kDa) and P44 (44 kDa). P44 is closely related to the cysteine- and histidine-rich protein of Trichinella, and p43 of Trichuris, the functions of which remain obscure. We present new information on the ligand-binding activity of P44. P17 is responsible for the intense red colour of adult D. renale and we show that P17 is a haem-containing member of the nemoglobin class of globins described from other nematode Clades. While nemoglobins are found across the diversity of the phylum Nematoda, P44 and related proteins may be a specialism evolved in Dorylaimia that replaces bulk lipid transport inside the parasites and potentially interacts with host tissues.