RESUMO
The 17ß-hydroxysteroid dehydrogenases (17ß-HSD) are key enzymes involved in the formation (reduction) and inactivation (oxidation) of sex steroids. Several types have been found in vertebrates including fish, as well as in invertebrates like Caenorhabditis elegans, Ciona intestinalis and Haliotis diversicolor supertexta. To date limited information is available about this enzyme in parasites. We showed previously that Taenia solium cysticerci are able to synthesize sex steroid hormones in vitro when precursors are provided in the culture medium. Here, we identified a T. solium 17ß-HSD through in silico blast searches in the T. solium genome database. This coding sequence was amplified by RT-PCR and cloned into the pcDNA 3.1(+) expression vector. The full length cDNA contains 957bp, corresponding to an open reading frame coding for 319 aa. The highest identity (84%) at the protein level was found with the Echinococcus multilocularis 17ß-HSD although significant similarities were also found with other invertebrate and vertebrate 17ß-HSD sequences. The T. solium Tsol-17ßHSD belongs to the short-chain dehydrogenase/reductase (SDR) protein superfamily. HEK293T cells transiently transfected with Tsol17ß-HSD induced expression of Tsol17ß-HSD that transformed 3H-androstenedione into testosterone. In contrast, 3H-estrone was not significantly transformed into estradiol. In conclusion, T. solium cysticerci express a 17ß-HSD that catalyzes the androgen reduction. The enzyme belongs to the short chain dehydrogenases/reductase family and shares motifs and activity with the type 3 enzyme of some other species.
Assuntos
17-Hidroxiesteroide Desidrogenases/genética , 17-Hidroxiesteroide Desidrogenases/metabolismo , Hormônios Esteroides Gonadais/biossíntese , Taenia solium/enzimologia , Taenia solium/genética , Sequência de Aminoácidos , Androstenodiona/biossíntese , Animais , Sequência de Bases , Clonagem Molecular , Regulação da Expressão Gênica , Células HEK293 , Humanos , Dados de Sequência Molecular , Filogenia , Testosterona/biossínteseRESUMO
Entamoeba histolytica antigens recognized by salivary IgA from infected patients include the 29 kDa antigen (Eh29), an alkyl hydroperoxide reductase. Here, we investigate the potential of recombinant Eh29 and an Eh29-cholera toxin subunit B (CTxB) fusion protein to confer protection against intestinal amoebiasis after oral immunization. The purified Eh29-CTxB fusion retained the critical ability to bind ganglioside GM(1), as determined by ELISA. Oral immunization of C3H/HeJ mice with Eh29 administered in combination with a subclinical dose of whole cholera toxin, but not as an Eh29-CTxB fusion, induced elevated levels of intestinal IgA and serum IgG anti-Eh29 antibodies that inhibited trophozoites adherence to MDCK cell monolayers. The 80% of immunized mice seen to develop IgA and IgG immune responses showed no evidence of infection in tissue sections harvested following intracecal challenge with virulent E. histolytica trophozoites. These results suggest that Eh29 is capable of inducing protective anti-amoebic immune responses in mice following oral immunization and could be used in the development of oral vaccines against amoebiasis.
Assuntos
Antígenos de Protozoários/imunologia , Antígenos de Superfície/imunologia , Toxina da Cólera/imunologia , Disenteria Amebiana/prevenção & controle , Entamoeba histolytica/imunologia , Proteínas Recombinantes/imunologia , Administração Oral , Animais , Anticorpos Antiprotozoários/biossíntese , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/administração & dosagem , Antígenos de Superfície/administração & dosagem , Ceco/parasitologia , Ceco/patologia , Toxina da Cólera/administração & dosagem , Cricetinae , Modelos Animais de Doenças , Vida Livre de Germes , Humanos , Imunização/métodos , Imunoglobulina A Secretora/biossíntese , Imunoglobulina A Secretora/sangue , Imunoglobulina G/biossíntese , Imunoglobulina G/sangue , Camundongos , Camundongos Endogâmicos C3H , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes/administração & dosagemRESUMO
The purpose of this work was to clarify the taxonomy and phylogenetic relationship of the Phyllosoma complex and other important vectors in Mexico. The internal transcribed spacer 2 (ITS-2) of rDNA and the cytochrome B gene of mtDNA (mtCytB) were analyzed for the following species of triatomine: Triatoma bassolsae, T. longipennis, T. mazzottii, T. mexicana, T. pallidipennis, T. picturata, and T. phyllosoma belonging to the Phyllosoma complex, as well as T. dimidiata, T. rubida, T. infestans, and Rhodnius prolixus. The results obtained with the analysis of the ITS-2 sequences showed that the Phyllosoma complex species could not be phylogenetically separated, since T. bassolsae and T. pallidipennis, as well as T. phyllosoma and T. mazzottii were indistinguishable. In contrast, the mtCytB gene separates each one of these triatomine species. The results support the proximity of all seven species currently included in the Phyllosoma complex as well as the exclusion of T. dimidiata. For the first time T. lecticularia and T. rubida were analyzed and were also shown to be related to the Phyllosoma complex.
Assuntos
Insetos Vetores/genética , Triatoma/classificação , Triatoma/genética , Animais , Sequência de Bases , Citocromos b/genética , DNA Mitocondrial/genética , DNA Ribossômico/genética , DNA Espaçador Ribossômico , México , Repetições de Microssatélites , Filogenia , Rhodnius/classificação , Rhodnius/genética , Alinhamento de Sequência , Estados UnidosRESUMO
To explore the bacterial microbiota in Chilean oyster (Tiostrea chilensis), a molecular approach that permits detection of different bacteria, independently of their capacity to grow in culture media, was used. Bacterial diversity was assessed by analysis of both the 16S rDNA and the 16S-23S intergenic region, obtained by PCR amplifications of DNA extracted from depurated oysters. RFLP of the PCR amplified 16S rDNA showed a prevailing pattern in most of the individuals analyzed, indicating that a few bacterial species were relatively abundant and common in oysters. Cloning and sequencing of the 16S rDNA with the prevailing RFLP pattern indicated that this rRNA was most closely related to Arcobacter spp. However, analysis by the size of the amplified 16S-23S rRNA intergenic regions revealed not Arcobacter spp. but Staphylococcus spp. related bacteria as a major and common component in oyster. These different results may be caused by the absence of target for one of the primers employed for amplification of the intergenic region. Neither of the two bacteria species found in large abundance was recovered after culturing under aerobic, anaerobic, or microaerophilic conditions. This result, however, is expected because the number of bacteria recovered after cultivation was less than 0.01% of the total. All together, these observations suggest that Arcobacter-related strains are probably abundant and common in the Chilean oyster bacterial microbiota.
Assuntos
Arcobacter/genética , Ostreidae/microbiologia , RNA Ribossômico 16S/genética , Animais , Arcobacter/fisiologia , Classificação , DNA Bacteriano/análise , DNA Bacteriano/genética , Reação em Cadeia da Polimerase , Dinâmica Populacional , RNA Ribossômico 16S/análiseRESUMO
Paramyosin has been proposed as a vaccine candidate in schistosomiasis and filariasis. However, limited information is available about its protective potential against cysticercosis and the immune response it induces. Immunization of mice with recombinant full-length paramyosin of Taenia solium (TPmy) results in about a 52% reduction in parasite burden after a subsequent challenge by intraperitoneal inoculation of Taenia crassiceps cysticerci. Immunization assays using recombinant fragments of TPmy, corresponding approximately to thirds on the amino, central, or carboxyl regions, suggest that protective epitopes are located mostly in the amino-end third. Proliferation assays using T cells obtained from mice immunized with the full-length recombinant TPmy also showed a preferential response to the amino-terminal fragment. In contrast, antibodies in the sera from these mice predominantly recognize epitopes located in the carboxyl-terminal fragment, being the immunoglobulin G1 subclass, the predominant antibody isotype. Characterization of the cellular immune response induced against the protective amino-terminal fragment reveals production of gamma interferon and interleukin-2, but not interleukin-4, suggesting a Th1-like profile.
Assuntos
Cisticercose/imunologia , Cisticercose/prevenção & controle , Taenia/imunologia , Tropomiosina/imunologia , Vacinas/imunologia , Animais , Anticorpos Anti-Helmínticos/sangue , Cisticercose/parasitologia , Citocinas/biossíntese , Modelos Animais de Doenças , Feminino , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Linfócitos T/imunologia , Tropomiosina/genética , VacinaçãoRESUMO
Epitope mapping of the amino-terminal 20aa sequence from Taenia solium paramyosin (TPmy), an immunodominant protein involved in the complex host-parasite relationship in human and porcine cysticercosis is reported. A 12-mer random peptide phage display library was screened with antibodies raised against a synthetic peptide corresponding to the amino-terminal 20aa sequence of TPmy, its highly immunodominant region. In total, 57 clones isolated in two panning conditions were analyzed, of which a single group of 14 sequences found in 25 clones shared a consensus motif showing structural similarity with the antigen Arg10-Thr16 region.
Assuntos
Epitopos de Linfócito B/imunologia , Epitopos Imunodominantes/imunologia , Taenia/imunologia , Tropomiosina/imunologia , Sequência de Aminoácidos , Animais , Mapeamento de Epitopos/métodos , Dados de Sequência Molecular , Peptídeos/imunologia , CoelhosRESUMO
This article reviews current knowledge on human and porcine cysticercosis caused by Taenia solium. It highlights the conditions favorable for its prevalence and transmission, as well as current trends in research on its natural history, epidemiology, immunopathology, diagnosis, treatment and prevention. Our opinions on the most urgent needs for further research are also presented.
Assuntos
Cisticercose/epidemiologia , Cisticercose/prevenção & controle , Países em Desenvolvimento , Taenia , Animais , Cisticercose/diagnóstico , Cisticercose/parasitologia , Cisticercose/veterinária , Saúde Global , Interações Hospedeiro-Parasita , Humanos , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/parasitologia , Taenia/crescimento & desenvolvimento , Taenia/imunologia , Taenia/ultraestruturaRESUMO
Platyhelminths, like many other organisms, are capable of producing mineral concretions. In cestodes these are referred to as calcareous corpuscles. Studies on these concretions in different cestodes both in vivo and in vitro have resulted in a number of hypotheses on their origin, formation, and structure. Calcareous corpuscles are believed to be of cellular origin, although the kind of cell involved and the mechanisms of mineralization remain under discussion. In the present paper we show that formation of calcareous corpuscles in cysticerci of Taenia solium is not of intracellular origin, as described for other cestodes, but occurs extracellularly in the lumen of protonephridial ducts in a way similar to that proposed for trematodes. This finding enhances the function of the protonephridial ducts, at least in the larvae of T. solium, to the roles formerly ascribed to the calcareous corpuscles.
Assuntos
Cysticercus/fisiologia , Cysticercus/ultraestrutura , Animais , Cisticercose/parasitologia , Cisticercose/veterinária , Cysticercus/isolamento & purificação , Microscopia Eletrônica , Músculo Esquelético/parasitologia , Suínos , Doenças dos Suínos/parasitologia , Vacúolos/fisiologia , Vacúolos/ultraestruturaRESUMO
Cysticercosis is a parasitic disease caused by the larval stage or cysticercus of the cestode tapeworm Taenia solium. Cysticerci are able to survive in the host tissues for long periods in the presence of an immune response. Tissues of cestodes contain mineral concretions termed calcareous corpuscles. These corpuscles might serve for the focal deposition of exceeding amounts of calcium protecting the larvae against calcification. Studies on the morphology and composition of calcareous corpuscles in cestodes have resulted in a number of hypotheses on their origin and function. Calcareous corpuscles are believed to form either intracellularly or extracellularly and the cell type involved, the place of formation and the mechanism of mineral deposition seem to be also diverse. This review intends to provide an updated guide to the published literature on calcareous corpuscles in cestodes, giving emphasis on their role in larval physiology. Understanding biomineralization might lead to novel ways for the treatment of diseases caused by cestode larvae.
Assuntos
Cestoides/fisiologia , Animais , Calcificação Fisiológica , Cálcio/análise , Cestoides/crescimento & desenvolvimento , Cestoides/ultraestrutura , Humanos , Larva , Magnésio/análise , Modelos Biológicos , Neurocisticercose/parasitologia , Neurocisticercose/patologia , Fosfatos/análise , Silício/análise , Difração de Raios X , Zinco/análiseRESUMO
Arsenic and vanadium are important environmental and industrial pollutants. Due to their widespread occurrence and potential genotoxicity, we studied the aneuploidy-inducing effects of these elements in cultured human lymphocytes using a variety of techniques including fluorescence in situ hybridization (FISH) with DNA probes for chromosomes 1 and 7, immunostaining of the lymphocyte spindle apparatus, and an in vitro assay measuring the polymerization and depolymerization of tubulin. Dose-related increases in hyperdiploidy were seen in lymphocyte cultures treated with sodium arsenite (NaAsO2) or vanadium pentoxide (V2O5) over concentrations ranging from 0.001 to 0.1 microM. NaAsO2-treated cells from different donors exhibited similar hyperdiploid frequencies, whereas substantial inter-individual variability was seen in the V2O5-treated cells. Examination of the spindle apparatus using an anti-beta-tubulin antibody indicated that these compounds might disrupt spindle formation by interacting with microtubules. Additional in vitro assays using purified tubulin indicated that both compounds inhibited microtubule assembly and induced tubulin depolymerization. These results indicate that in vitro exposure to both NaAsO2 and V2O5 can induce aneuploidy in human lymphocytes, and that this effect may occur through a disruption of microtubule function.
Assuntos
Aneuploidia , Arsenitos/toxicidade , Linfócitos/efeitos dos fármacos , Microtúbulos/efeitos dos fármacos , Compostos de Sódio/toxicidade , Compostos de Vanádio/toxicidade , Células Cultivadas , Dimerização , Feminino , Humanos , Linfócitos/patologia , Linfócitos/ultraestrutura , Masculino , Microtúbulos/ultraestruturaAssuntos
Reações Antígeno-Anticorpo/imunologia , Antígenos de Protozoários/imunologia , Disenteria Amebiana/imunologia , Entamoeba histolytica/imunologia , Imunoglobulina A Secretora/imunologia , Proteínas de Membrana/imunologia , Proteínas de Protozoários/imunologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Humanos , Dados de Sequência Molecular , Homologia de Sequência de AminoácidosAssuntos
DNA Complementar/genética , Taenia/genética , Tropomiosina/genética , Sequência de Aminoácidos , Animais , Antígenos de Helmintos/genética , Sequência de Bases , Clonagem Molecular , Colágeno/metabolismo , Proteínas Inativadoras do Complemento 1/genética , Escherichia coli/genética , Expressão Gênica , Dados de Sequência Molecular , Homologia de Sequência de Aminoácidos , Taenia/imunologia , Taenia/metabolismo , Tropomiosina/imunologia , Tropomiosina/metabolismoRESUMO
Crystals of virus-like particles (VLP) are described as occurring in the nuclei of damaged tegumentary cytons from carcasses of Taenia solium metacestodes that had been stripped of their teguments. The VLP are grouped as parallel lines of round particles in an hexagonal packaging of spheroids forming small or large crystals. The individual particles have an external diameter of 36-37 nm and a wall of 5-6 nm thick, which surround a cavity of lower electron density. As identical crystals were also observed in normal tissues of T. solium and of T. crassiceps, it is suggested that both species of cysticerci are normal carriers of a similar species of virus. The possible biological implications of this condition are discussed.
Assuntos
Corpos de Inclusão Viral/ultraestrutura , Taenia/microbiologia , Animais , Cristalização , Cisticercose/parasitologia , Microscopia Eletrônica , Suínos , Doenças dos Suínos/parasitologia , Taenia/ultraestruturaRESUMO
The metabolic adaptability of Taenia solium cysticerci was studied in vitro, by measuring their respiratory rate before, during, and after trypsin-induced evagination. Under aerobic conditions, the oxygen consumption increased about 40% during evagination of the cysticeri and returned to basal rates after the process was completed. The percentage of evagination induced by trypsin was not affected under anaerobic conditions or in the presence of respiratory poisons such as cyanide and carbon monoxide. These data indicate that cysticerci use either aerobic or anaerobic pathways according to oxygen availability in the environment. Results from experiments of irreversible respiratory poisoning using cyanide suggest the presence of an alternative respiratory chain. Proteolytic action of trypsin on a fibrous layer surrounding the invaginated larvae is suggested by histological evidence.