Akiko Yamazaki
Iwate University, Japan
Title: The enterotoxic activity of Sarcocystis fayeri 15 kDa protein
Biography
Biography: Akiko Yamazaki
Abstract
Genus Sarcocystis is a protozoa which has two-host life cycle. Herbivores are main intermediary hosts and genus Sarcocystis forms sarcocysts in their muscle tissue. Sarcocystosis has been known as a problem of economic loss in cattle but nowadays it is also known as a causative factor of food poisoning. The symptom of sarcocystic food poisoning is mainly gastroenteritidis but neurologic manifestation is also found. The pathogenic causing mechanism is not yet investigated in details, but we found a toxic candidate protein of 15 kDa molecular mass from the cysts of Sarcocystis fayeri. S. fayeri is identified a causative pathogen for food poisoning by eating raw horse meat. Now we tried to examine its function in more detail. First, we determined an amino acid sequence of the 15 kDa size protein and identified it as an actin depolymerizing factor (ADF). Then we synthesized a recombinant ADF protein. It showed an enterotoxic activity in a rabbit illeal loop test but did not cause any damages on viability of L929, Raw264 and Caco-2 cells. For further examination of enterotoxic activity we tried cytokine assay of recombinant ADF. The culture supernatant of RAW264 cells treated with the recombinant ADF for 24 hours was added into the medium for L929 fibroblast cells which are sensitive to TNF-alpha. After 24 hour culture, the viability of the L929 cells was found to be dead, suggesting TNF alpha production. In this study, we confirmed the enterotoxic activity of parasitic toxic candidate protein but further research will be necessary to elucidate the mechanism for neurotoxic aspect.