RESUMO
Differential display technique was applied in order to identify transcripts which are present in axenic amastigotes but not in promastigotes of the Leishmania panamensis parasites. One of them was cloned and the sequence reveals an open reading frame of 364 amino acids (approximately 40 kDa). The deduced protein is homologous to the serine/threonine protein kinases and specially to the mitogen activates protein kinases from eukaryotic species. Southern blot analysis suggest that this transcript, named lpmkh, is present in the genome of the parasite as a single copy gene. These results could imply that lpmkh could be involved in the differentiation process or the preservation of amastigotes in axenic conditions.
Assuntos
Vida Livre de Germes , Leishmania/genética , RNA Mensageiro/análise , RNA de Protozoário/análise , Sequência de Aminoácidos , Animais , Southern Blotting , Dados de Sequência Molecular , RNA Mensageiro/genética , RNA de Protozoário/genéticaRESUMO
The Plasmodium vivax merozoite surface protein-1 (PvMSP-1) has been considered a candidate for a malaria vaccine against erythrocytic stages. PvMSP-1 is immunogenic during natural infections and exhibits antigenic polymorphism. The extent of genetic polymorphism in a region between the so-called interspecies conserved blocks (ICBs) 2 and 4 of the PvMSP-1 was analyzed in 20 isolates taken from patients from two different areas in Colombia. Variation is unevenly distributed along this gene segment among the isolates. Comparative analysis of these sequences led to the definition of five sequence types (ST1 to 5). ST1 to ST4 exhibit a variation pattern associated with sequences present in the Salvador or Belem sequences. However, ST5 has clusters of sequence that have not been previously described. The changes found along the five variants confirm the important role of recombinational and/or gene conversion events in generating allelic diversity.
Assuntos
Malária Vivax/parasitologia , Proteína 1 de Superfície de Merozoito/genética , Plasmodium vivax/genética , Polimorfismo Genético , Sequência de Aminoácidos , Animais , Sequência de Bases , Colômbia , Sequência Consenso , DNA de Protozoário/química , Variação Genética , Humanos , Proteína 1 de Superfície de Merozoito/química , Dados de Sequência Molecular , Plasmodium vivax/química , Alinhamento de SequênciaAssuntos
Malária Falciparum/sangue , Peptídeos/genética , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Animais , Sequência de Bases , Colômbia , DNA de Protozoário/química , Eritrócitos/parasitologia , Eritrócitos/ultraestrutura , Humanos , Dados de Sequência Molecular , Plasmodium falciparum/química , Reação em Cadeia da Polimerase , Proteínas de Protozoários/química , TanzâniaRESUMO
Tuberculosis, caused by Mycobacterium bovis is emerging as the most important disease affecting cattle. Furthermore, it results in a major public health problem when transmitted to humans. Due to its difficult and non-specific diagnosis, M. bovis has been declared to be one of the etiologic agents causing significant economic loss in the cattle industry. Our group evaluated a more rapid and specific method, based on a new polymerase chain reaction species-specific primers, which amplifies a 470-base pair fragment of the M. bovis genome. A total of 275 milk-producing cows were studied by intradermal tuberculin test (ITT) which gave 184 positive and 91 negative cases. From them, 50 animals were taken from a cattle ranch free of tuberculosis. Three different samples were collected from each animal (blood, nasal mucus, and milk). Positive results were obtained from 26 animals by PCR (11.4%), 1 by bacteriological culturing (0.4%) and 1 by bacilloscopy (0.4%). This finding suggests, as in previous reports, that ITT, normally used for bovine tuberculosis detection, has the inconvenience of having a broad range of specificity and sensitivity, and the PCR technique is a more specific and sensitive test to detect infection associated with M. bovis. Therefore, we propose this PCR assay as a useful tool in the epidemiological characterization of infected animals in areas considered to be at high risk of transmission.
Assuntos
Mycobacterium bovis/isolamento & purificação , Tuberculose Bovina/diagnóstico , Animais , Bovinos , Colômbia/epidemiologia , Primers do DNA , Feminino , Genoma Viral , Humanos , Leite , Mycobacterium bovis/genética , Reação em Cadeia da Polimerase/métodos , Tuberculose Bovina/epidemiologia , ZoonosesRESUMO
A polyclonal serum sample from a lepromatous leprosy (LL) patient, which presented a specific recognition pattern for leprosin, was used to screen a Mycobacterium leprae genomic library constructed with DNA isolated from human lepromas. One clone, designated ML4-1, which expressed a specific antigenic determinant of M. leprae as part of a beta-galactosidase fusion protein, was isolated. The 1.932 bp M. leprae-derived genomic fragment was sequenced, and it had an incomplete open-reading frame shown to code for a 644 amino-acid polypeptide (72.3 kDa). Some partial nucleotide homology to the M. tuberculosis MTCY9C4 cosmid and the M. leprae B1913 cosmid were found. Southern blot assays using the 584 bp Eco RI-Bam HI fragment excised from the ML4-1 clone revealed that this sequence is present only in the M. leprae genome and not in the 24 different mycobacterial DNA tested. Two oligonucleotides based on the genomic sequence were also synthesized and used as amplifiers for a polymerase chain reaction (PCR) test, giving a positive signal exclusively in M. leprae DNA. Furthermore, 32 sequential synthetic peptides, 20 amino-acids long, spanning the entire protein corresponding to the hypothetical ML4-1 clone sequence, were synthesized and evaluated by ELISA. A peptide included in the 221-240 region was significantly recognized by either lepromatous leprosy or healthy tuberculosis contact patient sera. Thus, PCR amplification of this fragment, along with the recognition of its protein sequence by leprosy patient sera, could be a useful tool for a potential diagnostic method in the detection of M. leprae infection in the future.
Assuntos
Antígenos de Bactérias/genética , Hanseníase Virchowiana/imunologia , Mycobacterium leprae/genética , Mycobacterium leprae/imunologia , Sequência de Aminoácidos , Sequência de Bases , Ensaio de Imunoadsorção Enzimática , Biblioteca Genômica , Humanos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Mapeamento por Restrição , Análise de Sequência de DNARESUMO
The nucleotide sequence of the cry11Bb1 gene from Bacillus thuringiensis subsp. medellin was determined. The corresponding protein has a deduced molecular mass of 88.2 kDa, and is 60.9% and 83% identical to the proteins Cry11Aa1 and Cry11Ba1, respectively. The Cry11Bb1 protein contains five repetitive blocks of 16 amino acids at the C terminal part. It is highly toxic to first instar laboratory reared Aedes aegypti, Anopheles albimanus and Culex quinquefasciatus larvae.