RESUMO
The Boa constrictor is one of the world's largest vertebrate carnivores and is often found in urban areas in the city of Manaus, Brazil. The morphological identification of ticks collected from 27 snakes indicated the occurrence of Amblyomma dissimile Koch 1844 on all individuals sampled. In contrast, Amblyomma rotundatum Koch was found on only two snakes. An analysis of the 16S rRNA molecular marker confirmed the morphological identification of these ectoparasites.
A jiboia (Boa constrictor), vertebrado carnívoro, tem sido encontrada em abundância na área urbana de Manaus. A identificação morfológica dos carrapatos coletados em 27 dessas serpentes verificou a ocorrência de Amblyomma dissimile Koch 1844, em todos os exemplares avaliados e a presença de Amblyomma rotundatum Koch 1844, em duas dessas serpentes. A análise do marcador 16S rRNA confirma a identificação morfológica das espécies A. rotundatum e A. dissimile e apresenta novas sequências destes organismos.
Assuntos
Adulto , Feminino , Humanos , Masculino , Cromatografia Gasosa-Espectrometria de Massas , Glutamina/análogos & derivados , Glutamina/isolamento & purificação , Fenilbutiratos/farmacocinética , Pró-Fármacos/farmacocinética , Administração Oral , Glutamina/sangue , Glutamina/síntese química , Glutamina/farmacocinética , Glutamina/urina , Estrutura Molecular , Fenilacetatos/farmacocinética , Fenilbutiratos/administração & dosagemRESUMO
Reduced amide pseudopeptides have been proposed as structural probes that could be useful as potential malarial vaccine components. However, designing determined pseudopeptide sequences containing isoster peptide bonds, either on an asparagine (Asn) or on a glutamine (Gln) residues, can become difficult because these precursor amino acid aldehydes are obtained in yields lower than 0.5%. This work presents a new strategy for obtaining both Asn and Gln aldehydes based on a controlled side-chain protection approach as well as a suitable solvent partition procedure. FT-IR, (1) H-NMR and (13) C-NMR were used for molecule characterization and identification. Amino acid aldehydes were successfully incorporated into a 20-mer peptide from a malarial-relevant sequence, and their impact on the molecule's conformational properties was assessed.
Assuntos
Aldeídos/síntese química , Asparagina/síntese química , Glutamina/síntese química , Técnicas de Síntese em Fase Sólida/métodos , Aldeídos/química , Amidas/síntese química , Amidas/química , Asparagina/química , Glutamina/química , OxirreduçãoRESUMO
A proposed mechanism for the melanoma specific activity of phenolic amines is based upon the ability of the enzyme tyrosinase to oxidize these prodrugs to toxic intermediates. In this study, we synthesized an iodinated analog of gamma-L-glutaminyl-4-hydroxybenzene (GHB) with increased antimelanoma activity in both human and murine melanoma cell lines. GHB and gamma-L-glutaminyl-4-hydroxy-3-iodobenzene (I-GHB) were shown to be substrates for both mammalian and mushroom tyrosinase. Glutathione, a cellular antioxidant, inhibited tyrosinase mediated formation of gamma-L-glutaminyl-3,4-benzoquinone (GBQ) from GHB, inhibited melanin production, and blocked the inhibition of the enzyme thymidylate synthase by oxidized GHB. Buthionine sulfoximine (BSO) depletion of cellular glutathione enhanced the growth inhibitory activity and the inhibition of in situ thymidylate synthase by phenolic amines in melanoma cells. GHB and I-GHB were shown to be approximately 5- and 10-fold more cytotoxic, respectively, in highly metastatic B16-BL6 cells than in weakly metastatic B16-F1 cells with approximately equal tyrosinase activity. B16-BL6 cells had approximately 20-fold higher gamma-glutamyltranspeptidase (gamma-GTPase) activity than B16-F1 cells which suggested the possible involvement of this enzyme in the activation of the cytotoxicity of the phenolic amines. 4-Aminophenol, a product of gamma-GTPase reaction with GHB, was a substrate for tyrosinase and a potent inhibitor of in situ thymidylate synthase activity in melanogenic cells. In pigmented melanoma cells containing the enzyme tyrosinase, the quinone mediated mechanism of phenolic amine cytotoxicity may be uniquely important and the cellular antioxidant glutathione essential in the detoxification of these quinone-generated intermediates.