Jessica C. Kissinger

PlasmoDB: a functional genomic database for malaria parasites

PlasmoDB (http://PlasmoDB.org) is a functional genomic database for Plasmodium spp. that provides a resource for data analysis and visualization in a gene-by-gene or genome-wide scale. PlasmoDB belongs to a family of genomic resources that are housed under the EuPathDB (http://EuPathDB.org) Bioinformatics Resource Center (BRC) umbrella. The latest release, PlasmoDB 5.5, contains numerous new data types from several broad categories—annotated genomes, evidence of transcription, proteomics evidence, protein function evidence, population biology and evolution. Data in PlasmoDB can be queried by selecting the data of interest from a query grid or drop down menus. Various results can then be combined with each other on the query history page. Search results can be downloaded with associated functional data and registered users can store their query history for future retrieval or analysis.

MCScanX: a toolkit for detection and evolutionary analysis of gene synteny and collinearity

MCScan is an algorithm able to scan multiple genomes or subgenomes in order to identify putative homologous chromosomal regions, and align these regions using genes as anchors. The MCScanX toolkit implements an adjusted MCScan algorithm for detection of synteny and collinearity that extends the original software by incorporating 14 utility programs for visualization of results and additional downstream analyses. Applications of MCScanX to several sequenced plant genomes and gene families are shown as examples. MCScanX can be used to effectively analyze chromosome structural changes, and reveal the history of gene family expansions that might contribute to the adaptation of lineages and taxa. An integrated view of various modes of gene duplication can supplement the traditional gene tree analysis in specific families. The source code and documentation of MCScanX are freely available at http://chibba.pgml.uga.edu/mcscan2/.

TriTrypDB: a functional genomic resource for the Trypanosomatidae

TriTrypDB (http://tritrypdb.org) is an integrated database providing access to genome-scale datasets for kinetoplastid parasites, and supporting a variety of complex queries driven by research and development needs. TriTrypDB is a collaborative project, utilizing the GUS/WDK computational infrastructure developed by the Eukaryotic Pathogen Bioinformatics Resource Center (EuPathDB.org) to integrate genome annotation and analyses from GeneDB and elsewhere with a wide variety of functional genomics datasets made available by members of the global research community, often pre-publication. Currently, TriTrypDB integrates datasets from Leishmania braziliensis, L. infantum, L. major, L. tarentolae, Trypanosoma brucei and T. cruzi. Users may examine individual genes or chromosomal spans in their genomic context, including syntenic alignments with other kinetoplastid organisms. Data within TriTrypDB can be interrogated utilizing a sophisticated search strategy system that enables a user to construct complex queries combining multiple data types. All search strategies are stored, allowing future access and integrated searches. ‘User Comments’ may be added to any gene page, enhancing available annotation; such comments become immediately searchable via the text search, and are forwarded to curators for incorporation into the reference annotation when appropriate.

ToxoDB: an integrated Toxoplasma gondii database resource

ToxoDB (http://ToxoDB.org) is a genome and functional genomic database for the protozoan parasite Toxoplasma gondii. It incorporates the sequence and annotation of the T. gondii ME49 strain, as well as genome sequences for the GT1, VEG and RH (Chr Ia, Chr Ib) strains. Sequence information is integrated with various other genomic-scale data, including community annotation, ESTs, gene expression and proteomics data. ToxoDB has matured significantly since its initial release. Here we outline the numerous updates with respect to the data and increased functionality available on the website.

PlasmoDB: the Plasmodium genome resource. A database integrating experimental and computational data

PlasmoDB (http://PlasmoDB.org) is the official database of the Plasmodium falciparum genome sequencing consortium. This resource incorporates the recently completed P. falciparum genome sequence and annotation, as well as draft sequence and annotation emerging from other Plasmodium sequencing projects. PlasmoDB currently houses information from five parasite species and provides tools for intra- and inter-species comparisons. Sequence information is integrated with other genomic-scale data emerging from the Plasmodium research community, including gene expression analysis from EST, SAGE and microarray projects and proteomics studies. The relational schema used to build PlasmoDB, GUS (Genomics Unified Schema) employs a highly structured format to accommodate the diverse data types generated by sequence and expression projects. A variety of tools allow researchers to formulate complex, biologically-based, queries of the database. A stand-alone version of the database is also available on CD-ROM (P. falciparum GenePlot), facilitating access to the data in situations where internet access is difficult (e.g. by malaria researchers working in the field). The goal of PlasmoDB is to facilitate utilization of the vast quantities of genomic-scale data produced by the global malaria research community. The software used to develop PlasmoDB has been used to create a second Apicomplexan parasite genome database, ToxoDB (http://ToxoDB.org).

Adaptation of protein secretion to extremely high‐salt conditions by extensive use of the twin‐arginine translocation pathway

Halophilic archaea thrive in environments with salt concentrations approaching saturation. However, little is known about the way in which these organisms stabilize their secreted proteins in such ‘hostile’ conditions. Here, we present data suggesting that the utilization of protein translocation pathways for protein secretion by the Halobacteriaceae differs significantly from that of non‐haloarchaea, and most probably represents an adaptation to the high‐salt environment. Although most proteins are secreted via the general secretion (Sec) machinery, the twin‐arginine translocation (Tat) pathway is mainly used for the secretion of redox proteins and is distinct from the Sec pathway, in that it allows cytoplasmic folding of secreted proteins. tatfind (developed in this study) was used for systematic whole‐genome analysis of Halobacterium sp. NRC‐1 and several other prokaryotes to identify putative Tat substrates. Our analyses revealed that the vast majority of haloarchaeal secreted proteins were predicted substrates of the Tat pathway. Strikingly, most of these putative Tat substrates were non‐redox proteins, the homologues of which in non‐haloarchaea were identified as putative Sec substrates. We confirmed experimentally that the secretion of one such putative Tat substrate depended on the twin‐arginine motif in its signal sequence. This extensive utilization of the Tat pathway in haloarchaea suggests an evolutionary adaptation to high‐salt conditions by allowing cytoplasmic folding of secreted proteins before their secretion.

ToxoDB: accessing the Toxoplasma gondii genome

ToxoDB (http://ToxoDB.org) provides a genome resource for the protozoan parasite Toxoplasma gondii. Several sequencing projects devoted to T. gondii have been completed or are in progress: an EST project (http://genome.wustl.edu/est/index.php?toxoplasma=1), a BAC clone end-sequencing project (http://www.sanger.ac.uk/Projects/T_gondii/) and an 8X random shotgun genomic sequencing project (http://www.tigr.org/tdb/e2k1/tga1/). ToxoDB was designed to provide a central point of access for all available T. gondii data, and a variety of data mining tools useful for the analysis of unfinished, un-annotated draft sequence during the early phases of the genome project. In later stages, as more and different types of data become available (microarray, proteomic, SNP, QTL, etc.) the database will provide an integrated data analysis platform facilitating user-defined queries across the different data types.

The Plasmodium genome database

Designing and mining a eukaryotic genomics resource.

Origin, targeting, and function of the apicomplexan plastid

The discovery of a plastid in Plasmodium, Toxoplasma and related protozoan parasites provides a satisfying resolution to several long-standing mysteries: the mechanism of action for various surprisingly effective antibiotics; the subcellular location of an enigmatic 35 kb episomal DNA; and the nature of an unusual intracellular structure containing multiple membranes. The apicomplexan plastid highlights the importance of lateral genetic transfer in evolution and provides an accessible system for the investigation of protein targeting to secondary endosymbiotic organelles. Combining molecular genetic identification of targeting signals with whole genome analysis promises to yield a complete picture of organellar metabolic pathways and new targets for drug design.

Phylogenomic evidence supports past endosymbiosis, intracellular and horizontal gene transfer in Cryptosporidium parvum

BackgroundThe apicomplexan parasite Cryptosporidium parvum is an emerging pathogen capable of causing illness in humans and other animals and death in immunocompromised individuals. No effective treatment is available and the genome sequence has recently been completed. This parasite differs from other apicomplexans in its lack of a plastid organelle, the apicoplast. Gene transfer, either intracellular from an endosymbiont/donor organelle or horizontal from another organism, can provide evidence of a previous endosymbiotic relationship and/or alter the genetic repertoire of the host organism. Given the importance of gene transfers in eukaryotic evolution and the potential implications for chemotherapy, it is important to identify the complement of transferred genes in Cryptosporidium.ResultsWe have identified 31 genes of likely plastid/endosymbiont (n = 7) or prokaryotic (n = 24) origin using a phylogenomic approach. The findings support the hypothesis that Cryptosporidium evolved from a plastid-containing lineage and subsequently lost its apicoplast during evolution. Expression analyses of candidate genes of algal and eubacterial origin show that these genes are expressed and developmentally regulated during the life cycle of C. parvum.ConclusionsCryptosporidium is the recipient of a large number of transferred genes, many of which are not shared by other apicomplexan parasites. Genes transferred from distant phylogenetic sources, such as eubacteria, may be potential targets for therapeutic drugs owing to their phylogenetic distance or the lack of homologs in the host. The successful integration and expression of the transferred genes in this genome has changed the genetic and metabolic repertoire of the parasite.