The genome of Cryptosporidium hominis.
Cryptosporidium species cause acute gastroenteritis and diarrhoea worldwide. They are members of the Apicomplexa--protozoan pathogens that invade host cells by using a specialized apical complex and are usually transmitted by an invertebrate vector or intermediate host. In contrast to other Apicomplexans, Cryptosporidium is transmitted by ingestion of oocysts and completes its life cycle in a single host. No therapy is available, and control focuses on eliminating oocysts in water supplies. Two species, C. hominis and C. parvum, which differ in host range, genotype and pathogenicity, are most relevant to humans. C. hominis is restricted to humans, whereas C. parvum also infects other mammals. Here we describe the eight-chromosome approximately 9.2-million-base genome of C. hominis. The complement of C. hominis protein-coding genes shows a striking concordance with the requirements imposed by the environmental niches the parasite inhabits. Energy metabolism is largely from glycolysis. Both aerobic and anaerobic metabolisms are available, the former requiring an alternative electron transport system in a simplified mitochondrion. Biosynthesis capabilities are limited, explaining an extensive array of transporters. Evidence of an apicoplast is absent, but genes associated with apical complex organelles are present. C. hominis and C. parvum exhibit very similar gene complements, and phenotypic differences between these parasites must be due to subtle sequence divergence.
Xu
Ping
P
Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia 23284-2030, USA.
Widmer
Giovanni
G
Wang
Yingping
Y
Ozaki
Luiz S
LS
Alves
Joao M
JM
Serrano
Myrna G
MG
Puiu
Daniela
D
Manque
Patricio
P
Akiyoshi
Donna
D
Mackey
Aaron J
AJ
Pearson
William R
WR
Dear
Paul H
PH
Bankier
Alan T
AT
Peterson
Darrell L
DL
Abrahamsen
Mitchell S
MS
Kapur
Vivek
V
Tzipori
Saul
S
Buck
Gregory A
GA
D000818:Animals; D002875:Chromosomes / Q000235:genetics; D003458:Cryptosporidium / Q000145:classification / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D016785:Cryptosporidium parvum / Q000235:genetics; D004798:Enzymes / Q000235:genetics; D019143:Evolution, Molecular; D017125:Genes, Protozoan / Q000235:genetics; D018503:Genome, Protozoan; D023281:Genomics; D006801:Humans; D010641:Phenotype; D015800:Protozoan Proteins / Q000235:genetics
D004798:Enzymes; D015800:Protozoan Proteins