title: Evolution of mitosome metabolism and invasion-related proteins in Cryptosporidium.
abstract: The switch from photosynthetic or predatory to parasitic life strategies by apicomplexans is accompanied with a reductive evolution of genomes and losses of metabolic capabilities. Cryptosporidium is an extreme example of reductive evolution among apicomplexans, with losses of both the mitosome genome and many metabolic pathways. Previous observations on reductive evolution were largely based on comparative studies of various groups of apicomplexans. In this study, we sequenced two divergent Cryptosporidium species and conducted a comparative genomic analysis to infer the reductive evolution of metabolic pathways and differential evolution of invasion-related proteins within the Cryptosporidium lineage.
  
  
  
  In energy metabolism, Cryptosporidium species differ from each other mostly in mitosome metabolic pathways. Compared with C. parvum and C. hominis, C. andersoni possesses more aerobic metabolism and a conventional electron transport chain, whereas C. ubiquitum has further reductions in ubiquinone and polyisprenoid biosynthesis and has lost both the conventional and alternative electron transport systems. For invasion-associated proteins, similar to C. hominis, a reduction in the number of genes encoding secreted MEDLE and insulinase-like proteins in the subtelomeric regions of chromosomes 5 and 6 was also observed in C. ubiquitum and C. andersoni, whereas mucin-type glycoproteins are highly divergent between the gastric C. andersoni and intestinal Cryptosporidium species.
  
  
  
  Results of the study suggest that rapidly evolving mitosome metabolism and secreted invasion-related proteins could be involved in tissue tropism and host specificity in Cryptosporidium spp. The finding of progressive reduction in mitosome metabolism among Cryptosporidium species improves our knowledge of organelle evolution within apicomplexans.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.|Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.
authors.forename: Shiyou
authors.initials: S
authors.lastname: Liu
authors.affiliation: Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Roellig
authors.affiliation: State Key Laboratory of Bioreactor Engineering, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.|Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.
authors.forename: Yaqiong
authors.initials: Y
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Bioreactor Engineering, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.|Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Frace
authors.affiliation: Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Tang
authors.affiliation: College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China.
authors.forename: Longxian
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Bioreactor Engineering, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China. yyfeng@ecust.edu.cn.
authors.forename: Yaoyu
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA. lxiao@cdc.gov.
authors.forename: Lihua
authors.initials: L
authors.lastname: Xiao
mesh_terms: D002952:Citric Acid Cycle / Q000235:genetics; D020451:Contig Mapping; D003458:Cryptosporidium / Q000145:classification / Q000235:genetics*; D045222:Electron Transport Chain Complex Proteins / Q000378:metabolism; D004734:Energy Metabolism / Q000235:genetics; D019143:Evolution, Molecular; D016678:Genome; D053858:Metabolic Networks and Pathways / Q000235:genetics; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D015800:Protozoan Proteins / Q000378:metabolism
chemical_list: D045222:Electron Transport Chain Complex Proteins; D015800:Protozoan Proteins
keywords: Apicomplexa; Cryptosporidium; Genomics; Mitosome metabolism; Reductive evolution