Schistosome is a digenetic blood trematode parasite that causes schistosomiasis in humans. It has been considered one of the most severe human helminthiasis in terms of morbidity and mortality. Over 200 million people are infected in 76 tropical and sub-tropical countries, and more than 600 million people are at risk with this disease. Three principal species of the genus Schistosoma cause this chronic and debilitating disease - S. japonicum, S. mansoni and S. haematobium. The first of these is prevalent in The Philippines, parts of Indonesia, and is a major disease risk for 66 million people living in southern China. S. mansoni is widespread in Africa, Caribbean and South America. Both these 2 Schistosomes cause intestinal schistosomiasis. S. haematobium originated from Africa and East MED and cause urinary and genital schistosomiasis.
The S. japonicum genome project including the transcriptome project was launched in Chinese National Human genome Center at Shanghai (CHGCS) since 2000. Schisotosme has a very large and complex genome. The haploid genome is about 400 in size, 4 times larger than C. elegans and 3.4 times larger than Drosophila melanogaster. It is organized in 8 pairs of chromosomes including 7 pairs of autosomal chromosomes and one pair of sexual chromosomes (Z, W), homozygous (ZZ) for male and heterozygous (ZW) for female. About 40% of the genome is constituted of repetitive elements, and about 13,469 protein-coding genes are predicted in this genome.
top↑During their complex developmental cycle, schistosomes alternate between a mammalian host and a snail host via the medium of fresh-water. After burrowing out of a snail, free-swimming cercariae penetrate skin of the mammalian host, migrate through the blood via the lungs to the liver, and transform into schistosomula. These mature in about four weeks in the hepatic portal vein, mate, and migrate to their destination in the mesenteric venous plexus. Female worms produce thousands of eggs daily, which are discharged in the feces after a damaging passage through the intestinal wall. Eggs hatch, if they reach fresh water, to release free-swimming ciliated miracidia. Guided by light and chemical stimuli, miracidia of S. japonicum seek amphibious snails of the genus Oncomelania. Within the hemocoel of the snail, miracidia give rise asexually to numbers of sporocysts, within which further asexual propagation produces numerous cercariae.
top↑- Contigs: 95,265 (CNUS0000108051..CNUS0000203315)
- Scaffolds: 25,048 (CCON0000096785..CCON0000121832)
- Predicted mRNAs: 12,657 (CNUS0000095394..CNUS0000108050)
- Predicted proteins: 12,657 (CPRT0000000001..CPRT0000012657)
- BAC complete sequences: 22(CNUS0000203316..CNUS0000203337)
- Full length cDNA: 17,401 (CNUS0000203338..CNUS0000220738)
- Retrotransposon: 25 (CNUS0000220741..CNUS0000220765)
To retrieve the Schistosoma japonicum data, first you should choose the database from the Database droplist, then enter the query word in the Query word text field (you can query by providing one of the following three fields: Gene Symbol, Accession number and Locus Name), finally click the Search button to perform the search.