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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #312905
Title: Systems based analysis of the Sarcocystis neurona genome identifies pathways that contribute to a heteroxenous life cycle

Author
item BLAZEJEWSKI, BLAZEJEWKSI - Hospital For Sick Children (SICKKIDS)
item NURSIMULU, NIRVANA - Hospital For Sick Children (SICKKIDS)
item PSZENNY, VIVIANA - National Institutes Of Health (NIH)
item DANGOUDOUBIYAM, SRIVENY - University Of Kentucky
item NAMASIVAYAM, SIVARANJANI - University Of Georgia
item CHIASSON, MELISSA - National Institutes Of Health (NIH)
item CHESSMAN, KYLE - Hospital For Sick Children (SICKKIDS)
item TONKIN, MICHELLE - University Of Victoria
item SESHADRI, SWAPNA - Hospital For Sick Children (SICKKIDS)
item HUNG, STACY - University Of Victoria
item BRIDGERS, JOSHUA - University Of Victoria
item RICKLEFS, STACY - University Of Toronto
item BOULANGER, MARTIN - University Of Victoria
item Dubey, Jitender

Submitted to: mBio
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2014
Publication Date: 2/10/2015
Citation: Blazejewski, B., Nursimulu, N., Pszenny, V., Dangoudoubiyam, S., Namasivayam, S., Chiasson, M., Chessman, K., Tonkin, M., Seshadri, S., Hung, S., Bridgers, J., Ricklefs, S., Boulanger, M., Dubey, J.P. 2015. Systems based analysis of the Sarcocystis neurona genome identifies pathways that contribute to a heteroxenous life cycle. mBio. 6(1):e02445-14.

Interpretive Summary: Sarcocystis neurona is a member of the coccidia, a clade of single celled apicomplexan parasites responsible for causing major economic and health burdens worldwide. A cousin of Plasmodium, Cryptosporidium, Theileria, and Eimeria, Sarcocystis is one of the most successful parasite genera; capable of infecting all vertebrates (fish, reptiles, birds and mammals – including humans). The past decade has witnessed an increasing number of human outbreaks of clinical significance associated with acute sarcocystosis. Among Sarcocystis species S. neurona has a wide host range and causes fatal encephalitis in horses, marine, and several other mammals. To provide insights into the transition from a purely enteric parasite (e.g. Eimeria) to one that forms tissue cysts (Toxoplasma), we present the first genome sequence of Sarcocystis neurona. Comparisons with other coccidian genomes highlights the molecular innovations that drive its distinct life cycle strategies. These findings will be of interest to biologists and Parasitologists.

Technical Abstract: Sarcocystis neurona is a member of the Coccidia, a clade of single-celled parasites of medical and veterinary importance including Eimeria, Sarcocystis, Neospora and Toxoplasma. Unlike Eimeria, a single host enteric pathogen, Sarcocystis, Neospora and Toxoplasma are two host parasites that infect and produce infectious tissue cysts in a wide range of intermediate hosts. As a genus, Sarcocystis is one of the most successful protozoan parasites; all vertebrates, including birds, reptiles, fish and mammals are hosts to at least one Sarcocysti species. Here we sequenced Sarcocystis neurona, the causal agent of fatal equine protozoal myeloencephalitis. The S. neurona genome is 127 Mbp, more than twice the size of other sequenced coccidian genomes. Comparative analyses identified conservation of the invasion machinery among the coccidia. However many dense granule and rhoptry kinase genes, responsible for altering host effector pathways inTox oplasma and Neospora, are absent from S. neurona. Further, S. neurona has a divergent repertoire of SRS proteins, previously implicated in tissue cyst formation in Toxoplasma. Systems based analyses identified a series of metabolic innovations, including the ability to exploit alternative sources of energy. Finally we present a S. neurona model detailing conserved molecular innovations that promote the transition from a purely enteric lifestyle (Eimeria) to a heteroxenous parasite capable of infecting a wide range of intermediate hosts.