title: An analysis of dinoflagellate metabolism using EST data.
abstract: The dinoflagellates are an important group of eukaryotic, single celled algae. They are the sister group of the Apicomplexa, a group of intracellular parasites and photosynthetic algae including the malaria parasite Plasmodium. Many apicomplexan mitochondria have a number of unusual features, including the lack of a pyruvate dehydrogenase and the existence of a branched TCA cycle. Here, we analyse dinoflagellate EST (expressed sequence tag) data to determine whether these features are apicomplexan-specific, or if they are more widespread. We show that dinoflagellates have replaced a key subunit (E1) of pyruvate dehydrogenase with a subunit of bacterial origin and that transcripts encoding many of the proteins that are essential in a conventional ATP synthase/Complex V are absent, as is the case in Apicomplexa. There is a pathway for synthesis of starch or glycogen as a storage carbohydrate. Transcripts encoding isocitrate lyase and malate synthase are present, consistent with ultrastructural reports of a glyoxysome. Finally, evidence for a conventional haem biosynthesis pathway is found, in contrast to the Apicomplexa, Chromera and early branching dinoflagellates (Perkinsus, Oxyrrhis).
authors.affiliation: Sansom Institute for Health Research, University of South Australia, North Terrace, Adelaide, SA 5000, Australia.
authors.forename: Erin R
authors.initials: ER
authors.lastname: Butterfield
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Howe
authors.forename: R Ellen R
authors.initials: RE
authors.lastname: Nisbet
mesh_terms: D004141:Dinoflagellida / Q000235:genetics* / Q000378:metabolism*; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D008954:Models, Biological