(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Eukaryota: NE > Fornicata: NE > Diplomonadida: NE > Hexamitidae: NE > Giardiinae: NE > Giardia: NE > Giardia intestinalis: NE
Warning: This entry is a compilation of different species or line or strain with more than 90% amino acide identity. You can retrieve all strain data
(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) Giardia lamblia ATCC 50803: N, E.
Giardia intestinalis: N, E.
Giardia intestinalis ATCC 50581: N, E.
Giardia lamblia P15: N, E.
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA MTLSAWIILVTLAMASVLTPEDNVRLRRLTAYVANADASIVLLTYTEYEE GTNHGNSMLWRINDPLEAEYPFDPDDISLLNAERVCPELVGVGDLQYSTH NQAFYFTAQGPDGTSQVYSYNHKLETCTQISFLPISVSNLKVSPKGNSVL FSAEIFVYPNNHASVDDPLNFAHDEFARIQARPYKAFAYEQLYTRHWDED ILPSQYRHLFAARLERSSEYDDDYVRITVDNSIDLMPRFDGDCPMRPFAD ASSYTFDSHGRYVAFVTQVGSTAAFYTNDSIWITDLQQFLDAKKPVRDVV LPLRCATCWNKARDQRPAFSYDGIFLYYASMDEEQSESDLLRLRKQNVSD LFEYDCDSLFCGPVTGEGVFNLTAGVFDRSIGQFIIPTDSTEDSIYILAE DHARTNLFRYNEESSTVTRLTYNGTLGSLLYLRHNKIFLATMSSYTRPTD LVMLDLTVATEFTATRDPSDTMKDDLIKISYLTDLNRQRLRHIDELQEPE EFYLPSKSFPDQYVHSWYFAPANLRDSHEYPLILYVHGGPESPWANSWSY RWNPQLIAARGYGVLATNFHGSSSFGEVFQKSVRGNWYSYPLEDIMDAWS NIYTHADKAYLSREKVCAMGASFGATFMNYMNSHVNNVTCYVTHDGVFDT MCNALETDELFFPVRELGGFLLDEQVDNQQLYEKWNPARFVENMSAPMLV IHGQKDYRIQVYHGISLFQALRLRGIKTKLVYFPTQSHWVWQPQESLFWH TQVFDWLDTYL
BACKGROUND: Giardia intestinalis is a protozoan parasite that causes diarrhea in a wide range of mammalian species. To further understand the genetic diversity between the Giardia intestinalis species, we have performed genome sequencing and analysis of a wild-type Giardia intestinalis sample from the assemblage E group, isolated from a pig. RESULTS: We identified 5012 protein coding genes, the majority of which are conserved compared to the previously sequenced genomes of the WB and GS strains in terms of microsynteny and sequence identity. Despite this, there is an unexpectedly large number of chromosomal rearrangements and several smaller structural changes that are present in all chromosomes. Novel members of the VSP, NEK Kinase and HCMP gene families were identified, which may reveal possible mechanisms for host specificity and new avenues for antigenic variation. We used comparative genomics of the three diverse Giardia intestinalis isolates P15, GS and WB to define a core proteome for this species complex and to identify lineage-specific genes. Extensive analyses of polymorphisms in the core proteome of Giardia revealed differential rates of divergence among cellular processes. CONCLUSIONS: Our results indicate that despite a well conserved core of genes there is significant genome variation between Giardia isolates, both in terms of gene content, gene polymorphisms, structural chromosomal variations and surface molecule repertoires. This study improves the annotation of the Giardia genomes and enables the identification of functionally important variation.
The genome of the eukaryotic protist Giardia lamblia, an important human intestinal parasite, is compact in structure and content, contains few introns or mitochondrial relics, and has simplified machinery for DNA replication, transcription, RNA processing, and most metabolic pathways. Protein kinases comprise the single largest protein class and reflect Giardia's requirement for a complex signal transduction network for coordinating differentiation. Lateral gene transfer from bacterial and archaeal donors has shaped Giardia's genome, and previously unknown gene families, for example, cysteine-rich structural proteins, have been discovered. Unexpectedly, the genome shows little evidence of heterozygosity, supporting recent speculations that this organism is sexual. This genome sequence will not only be valuable for investigating the evolution of eukaryotes, but will also be applied to the search for new therapeutics for this parasite.
Giardia is a flagellated protozoan that resides in the upper small intestine of its vertebrate host and is the most common cause of defined waterborne diarrhoea worldwide. Giardia trophozoites undergo significant biological changes to survive outside the host by differentiating into infective cysts. Encystation is thus essential for transmission of the parasite among susceptible hosts. In the present study, we report that bestatin, a competitive inhibitor of aminopeptidases, blocks cyst formation in vitro by abolishing the expression of encystation-specific genes, such as those coding for cyst wall proteins. Bestatin does not affect proliferating trophozoites, indicating that its effect is encystation-specific. Using biochemical and molecular biological approaches, we identified the enzyme inhibited by bestatin and cloned its corresponding gene. Sequence similarity indicated that this enzyme belongs to a family of dipeptidyl peptidases. Our results suggest that a specific proteolytic event caused by a constitutively expressed membrane-associated dipeptidyl peptidase IV is necessary for encystation of Giardia.
