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
Gestation age and ability of the baby to self-quiet and to be consoled during the first 30 days of life decrease when mother's blood lead levels rise from 36 weeks of pregnancy to birth of child. These effects appear to be independent of the absolute lead levels of mother and child (N = 42). Since pre- and perinatal stress predicts higher maternal birth lead, further work could determine the relative contributions of undetected stress during pregnancy and elevated lead levels upon subsequent development. Several cases, not included in the statistical analyses, showed associations between cord leads greatly elevated over maternal leads and poor outcome.
Assuntos
Recém-Nascido/fisiologia , Intoxicação por Chumbo/fisiopatologia , Chumbo/sangue , Troca Materno-Fetal , Adulto , Dieta , Feminino , Humanos , Intoxicação por Chumbo/psicologia , México , Gravidez , Fumar , População UrbanaAssuntos
Infecções por Nematoides/veterinária , Doenças dos Roedores/parasitologia , Angiostrongylus/isolamento & purificação , Angiostrongylus/patogenicidade , Animais , Cricetinae , Interações Hospedeiro-Parasita , Humanos , Mesocricetus/parasitologia , Infecções por Nematoides/parasitologia , Ratos , Especificidade da EspécieRESUMO
Se infestaron experimentalmente 12 hamsteres con 6 y 10 larvas infestivas de Angiostrongylus cantonesis. Se observo un promedio de sobrevivencia inferior a 30,3 dias, y que los parasitos alcanzaron los pulmones antes que en su hospedero habitual. En ningun caso se encontraron larvas en las heces