RESUMO
The helminth Trichostrongylus colubriformis is a parasitic nematode infecting the small intestine of sheep. We report the isolation and characterization of a 30-kDa glycoprotein capable of partially protecting guinea-pigs against the parasite. This glycoprotein is secreted by the L4 and adult parasitic stages of the worm. The sequence of three separate cDNA clones predicts the polypeptide to be about 15 kDa, with four N-linked carbohydrate chains and an internal disulphide bond. The clones also indicate the existence of sequence variability in this antigen. Limited sequence homology to a porcine intestinal peptide suggests an influence on host gut physiology.
Assuntos
Antígenos de Helmintos/imunologia , Glicoproteínas/imunologia , Proteínas de Helminto/imunologia , Tricostrongiloidíase/imunologia , Tricostrongilose/imunologia , Trichostrongylus/imunologia , Sequência de Aminoácidos , Animais , Antígenos de Helmintos/genética , Antígenos de Helmintos/isolamento & purificação , Sequência de Bases , Northern Blotting , Clonagem Molecular , DNA/genética , Dissulfetos , Escherichia coli/genética , Glicoproteínas/genética , Glicoproteínas/isolamento & purificação , Cobaias , Proteínas de Helminto/genética , Proteínas de Helminto/isolamento & purificação , Dados de Sequência Molecular , RNA Mensageiro/biossíntese , Trichostrongylus/genética , Trichostrongylus/metabolismo , Vacinas/imunologiaRESUMO
Testosterone, progesterone and cholesterol were found in mixed sexes of the nematode Trichostrongylus colubriformis from goats, according to thin-layer, gas-liquid and high-performance liquid chromatography. The structure of these steroids was confirmed by proton nuclear magnetic resonance and mass spectroscopy. Melting points of the worms' steroids were similar to authentic standards of the steroids. Estradiol was not detected in worms from either goat sex. Cholesterol was about 0.08% of the worms' dry weight in helminths from either sex of host. Testosterone was 0.02% of the dry weight when worms were taken from male goats, but only 0.005% from female goats. Progesterone was not detected in worms from male goats, but was 0.005% of the dry weight of helminths from female hosts. Incubation of a worm preparation with tritiated steroids showed that progesterone was converted to 17-alpha-hydroxyprogesterone, based on retention during radioactive thin-layer and gas-liquid chromatography, and co-crystallization. Testosterone, cholesterol and 17-beta-estradiol were not metabolized.