Bio-Strings: A Relational Database Data-Type for Dealing with Large Biosequences.

DNA sequencers output a large set of very long biological data strings that we should persist in databases rather than basic text file systems. Many different data models and database management systems (DBMS) may deal with both storage and efficiency issues regarding genomic datasets. Specifically, there is a need for handling strings with variable sizes while keeping their biological meaning. Relational database management systems (RDBMS) provide several data types that could be further explored for the genomics context. Besides, they enforce integrity, consistency, and enable good abstractions for more conventional data. We propose the relational text data type to represent and manipulate biological sequences and their derivatives. We present a logical schema for representing the core biological information, which may be inferred from a given biological conceptual data schema and the corresponding function manipulations. We implement and evaluate these stored functions into an actual RDBMS for both efficacy and efficiency. We show that it is possible to enforce basic and complex requirements for the genomic domain. We claim that the well-established relational text data type in RDBMS may appropriately handle the representation and persistency of biological sequences. We base our approach on the idea of domain-specific abstract data types that can store data with semantically defined functions while hiding those details from non-technical end-users.

Genotype variation and stability of four variable-number tandem repeats and their suitability for discriminating strains of Mycobacterium leprae

It has not been possible to distinguish different strains of Mycobacterium leprae according to their genetic sequence. However, the genonme contais several variable-number tandem repeats (VNTR), which have been used effectively in strain typing of other bacteria. To determine their suitability for differentiating M. leprae, we developed PCR systems to amplify 5 different VNTR loci and examined a battery of 12 M. leprae strains derived from patients in different regions of the United States, Brazil, Mexico, and the Philippines, as well as from wild armadillos and sooty mangabey monkey. We found diversity at for VNTR (D = 0.74), butone system (C16G8) failed to yield reproducible results. Alleles for the GAA VNTR varied in length from 9 to 12 copies, andthose for AT17 varied in length from 13 to 20 copies. Relatively little variation was seen with interspecies transfer of bacilli or during short-term passage of strains in nude mice or armadillos. The TA18 locus was more polymorphic than other VNTR, and genotypic variation was more common after long-term expansion in armadillos. Most strain genotypes remained fairly stable in passage, but atrain Thai-53 showed reamrkable any particular genotype associable with different regions or hosts of origen. VNTR polymorphisms can be used effectively to discriminate M. leprae strains. Inclusion of additional loci and other elements will likely lead to robust typing system that can be used in community-based epidemiological studies and select clinical application

TcruziDB, an integrated database, and the WWW information server for the Trypanosoma cruzi genome project

Data analysis, presentation and distribution is of utmost importance to a genome project. A public domain software, AdDB, has been chosen as the common basis for parasite genome databases, and a first release of TcruziDB, the Trypanosoma cruzi genome database, is available by ftp from ftp://irisdbbm.fiocruz.br/pub/genomedb/TcruziDB as well as versions of the software for different operating systems (ftp://iris.dbbm.fiocruz.br/pub/unixsoft/). Morever, data originated from the project are available from the WWW server at http://www.dbbm.fiocruz.br. It contains biological and parasitological data on CL Brener, its karytype, all available T. cruzi sequences from Genbank, data on th EST-sequencing project and on available libraries, a T. cruzi codon table and a listing of activities and participating groups in the genome project, as well as meeting reports. T. cruzi discussion lists (tcruzi-l@iris.dbbm.fiocruz.br and tcgenics@iris.dbbm.fiocruz.br) being maintained for communication and to promote collaboration in the genome project.

Identification of transcribed sequences (ESTs) in the Trypanosoma cruzi genome project

Random single pass sequencing of cDNA fragments, also known as generation of Expressed Sequence Taggs (ESTs), has been highly successful in the study of the gene content of higher organisms, and forms an integral part of most genome projects, with the objective to identify new genes and targets for disease control and prevention and to generate mapping probes. In the Trypanosoma cruzi genome project, EST sequencing has also been a starting point, and here we report data on the first 797 sequences obtained, partly from a CL Brener epimastigote non-normalized library, partly on a normalized library. Only around 30 per cent of the sequences obtained showed similarity with Genbank and dbEST databases, half of which with sequences already reported for T. cruzi.

An oligonucleotide probe derived from kDNA minirepeats is specific for Leishmania (Viannia)

Sequence analysis of Leishmania (Viannia) kDNA minicircles and analysis of multiple sequence alignments of the conserved region (minirepeats) of five distinct minicircles from L. (V.) braziliensis species with corresponding sequences derived from other dermotropic leishmanias indicated the presence of a sub-genus specific sequence. An oligonucleotide bearing this sequence was designed and used as a molecular probe, being able to recognize solely the sub-genus Viannia species in hybridization experiments. A dendrogram reflecting the homologies among the minirepeat sequences was constructed. Sequence clustering was obtained corresponding to the traditional classification based on similarity of biochemical, biological and parasitological characteristics of these Leishmania species, distinguishing the Old World dermotropic leishmanias, the New World dermotropic leishmanias of the sub-genus Leishmania and of the sub-genus Viannia.

Use of PCR for the determination of the frequency of the F508 mutation in Brasilian cistic fibrosis patients

The F508 mutation in the cystic fibrosis (CF) gene was studied in a population of 18 Brazilian CF patients and their 17 families by use of PCR and differential hybridization with oligonucleotides. In a total of 34 chromosomes considered, 12 (35%) carried the F508 deletion, a frequency much lower than that reported in most other populations. As a consequence, CF in Brazil would be predominantly caused by mutations different from the F508 deletion