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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surface radioiodination of adult Onchocerca parasites reveals a restricted range of proteins associated with the cuticle. We present data to show that prominent among these is a complex of low-molecular-weight proteins which can be released in soluble form by homogenisation of surface-labelled Onchocerca gutturosa in phosphate-buffered saline (PBS). One of this groups of proteins, designated gp20, has a molecular mass of 20,000, is glycosylated with two N-linked carbohydrate side chains, and has a basic pI. Other PBS-soluble, 125I-labelled proteins of similar size appear not to be glycosylated. A distinct group of molecules are released only in the presence of reducing agents, and are likely to be cuticular collagens. The low-molecular-weight components are antigenic and cross-reactive with Onchocerca volvulus infection sera. Cross-reactions are also observed in immunoprecipitation experiments using sera from Brugia-immunised animals and infected humans. Comparative two-dimensional analyses of these immunoprecipitates reveal at least two Onchocerca specific components. As an alternative to radiolabelling and PBS homogenisation, incubation of worms in medium containing the reducing agent 2-mercaptoethanol resulted in a similar set of molecules being released into the medium. Since surface antigens of O. gutturosa from bovines and O. volvulus from humans appear similar in size and are antigenically cross-reactive, the more readily available parasite is being used to study further the properties of these molecules and to provide reagents for raising antisera reactive to the equivalent O. volvulus antigens.
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PMID:Biochemical and immunochemical characterisation of a 20-kilodalton complex of surface-associated antigens from adult Onchocerca gutturosa filarial nematodes. 273 28

A preparation of the cuticle of Onchocerca volvulus was obtained by extracting worm fragments in an series of buffers with 1.5% Triton-X-100 and 3% Sodium dodecyl sulfate (SDS). Electron micrographs of worm fragments, treated with the detergents or collagenase showed that our methods had been effective in isolating the cuticle from the other organs of the parasite. The cuticular preparation was found to contain 19 different amino acids with glycine (23.4%); proline (11.23%); hydroxyproline (10%); and glutamic acid (9.4%) being the most abundant. Hydroxylysine was present in small amounts (0.04%). Total reducing sugar was determined to be 5.3 mg per gram dry weight of the preparation. The cuticular preparation was solubilized by boiling in 2-mercaptoethanol and shown by SDS-PAGE to contain at least 10 different polypeptides in the Mr range 17,000-163,000. Five of these polypeptides with apparent Mr respectively of 33,000; 67,000; 74,000, 88,500 and 114,000 were isolated by preparative gel electrophoresis and their amino acid compositions shown to be similar to that of invertebrate collagens. We conclude that the cuticle of O. volvulus contains collagen-like proteins held together by disulfide bridges.
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PMID:Isolation and biochemical composition of the cuticle of Onchocerca volvulus. 284 63

To determine whether morphologic changes are accompanied by variations in the biochemical and antigenic properties of the cuticle of Onchocerca volvulus during development, we isolated and compared the 2-mercaptoethanol soluble cuticular proteins and the insoluble cuticlin from the predominant life-cycle stages occurring in man. SDS-PAGE analysis, before and after digestion with collagenase from Achromobacter iophagus, revealed that the polypeptide composition of the 2-mercaptoethanol-solubilised extracts from adult males and nodular microfilariae are quite distinct and that these extracts contained predominantly collagen-like proteins. Demonstrated by immunoblotting with a hyper immune patient serum pool (n = 107), five strongly reactive antigens with apparent molecular weights of 126, 68, 43, 37 and 33 kDa were detected in the extracts from adult males, while at least eight prominent and several weakly reactive components were detected in the extracts from nodular microfilariae. The overall amino acid composition of the cuticular extracts from the various stages demonstrates that: (a) the cuticle of the adult male stage is rich in glycine, pyrrolidone amino acids, and acidic amino acids or their amides, (b) eggshells are particularly poor in proline but rich in serine residues (14.5%), (c) nodular microfilariae cuticular extracts are poor in proline but rich in valine (9.0%) and lysine (7.3%) and (d) hydroxyproline and hydroxylysine are present in the cuticle of adults but absent in the juvenile life-cycle stages (nodular microfilariae and eggs). This study firstly, indicates that the composition of the cuticle of O. volvulus may thus, be quite distinct from one parasite stage to another and secondly, that the maturation of the parasite in the human host may be accompanied by the extensive hydroxylation of prolyl residues and to a lesser extent of lysyl residues in the predominantly collagen-like cuticular proteins.
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PMID:Evidence for increased hydroxylation of pyrrolidone amino acid residues in the cuticle of mature Onchocerca volvulus. 919 61