Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A full-length mRNA encoding a secreted 26-kDa antigen of infective larvae of the ascarid nematode parasite Toxocara canis has been identified. This was characterized as a 1,082-base pair clone highly abundant (0.8-1.9%) in cDNA prepared from infective stage larvae but absent from cDNA from adult male worms. Sequence analysis revealed an open reading frame corresponding to a hydrophilic 263-amino acid residue polypeptide with a 20-residue N-terminal signal peptide, indicating that it is secreted. The 5' end of the cDNA was isolated by polymerase chain reaction using a primer containing the nematode-spliced leader sequence, SL1, showing that the mRNA is trans-spliced. The molecular mass of the putative protein with the signal peptide removed is 26.01 kDa, and antibody to the recombinant protein expressed in bacterial vectors reacts with a similarly sized protein in T. canis excretory/secretory (TES) products. An identical sequence was obtained from a genomic clone isolated by expression screening with mouse antibody to TES. The 72 amino acid residues adjacent to the signal peptide form two homologous 36-residue motifs containing 6 cysteine residues; this motif is found also in the T. canis-secreted glycoprotein TES-120 and in genes of Caenorhabditis elegans. Sequence data base searches revealed significant similarity to 7 other sequences in a newly recognized gene family of phosphatidylethanolamine-binding proteins that includes yeast, Drosophila, rat, bovine, simian, and human genes and a representative from the filarial nematode Onchocerca volvulus. Assays with the T. canis recombinant 26-kDa protein expressed as a fusion with maltose-binding protein have confirmed phosphatidylethanolamine-binding specificity for this novel product.
 ...
PMID:An abundant, trans-spliced mRNA from Toxocara canis infective larvae encodes a 26-kDa protein with homology to phosphatidylethanolamine-binding proteins. 762 80

Onchocerca volvulus, a human parasitic nematode, is the third leading cause of preventable blindness worldwide. This study describes the molecular cloning of a novel superoxide dismutase (SOD) from the parasite. This putative O. volvulus extracellular SOD (OvEcSOD) is 628 nucleotides (nt) long, including a 22-nt 5' spliced leader (SL1) and a portion encoding an N-terminal hydrophobic 42-amino-acid signal peptide. The remainder of the cDNA shares 71% identity with an O. volvulus cytosolic SOD sequence and is 3 nt longer. All residues involved in metal ion binding, active site formation, folding, and dimer formation in SODs are conserved. Data indicate the OvEcSOD and O. volvulus cytosolic SOD are separate gene products and that the OvEcSOD appears to possess the characteristics of a membrane-bound or secreted enzyme which may be involved in the parasite defense against phagocyte-generated reactive oxygen species.
 ...
PMID:Molecular cloning of an Onchocerca volvulus extracellular Cu-Zn superoxide dismutase. 830 Feb 30

A monoclonal antibody raised to a Teladorsagia circumcincta 31-33 kDa doublet antigen was used to immunoscreen a T. circumcincta cDNA expression library. Sheep antibodies eluted from the proteins expressed by two clones immunopositive with the monoclonal antibody specifically recognised the doublet antigen on Western blots of third stage larval extract, confirming that these clones coded for the antigen. Database searches revealed high levels of similarity with beta-galactoside-binding lectin-like proteins (Ga1BPs or galectins) from Caenorhabditis elegans and Onchocerca volvulus. By analogy with these sequences, both T. circumcincta cDNA clones contain the full-length protein coding region. The native doublet proteins could be preferentially extracted from homogenates of third stage larvae with lactose and could be affinity purified on an asialofetuin column, confirming the identity of these bands as galectins. Reverse transcriptase-polymerase chain reaction amplification using a primer based on the C. elegans Spliced Leader SL1 sequence showed that the corresponding T. circumcincta mRNAs are also trans-spliced at their 5' ends. While there are considerable nucleotide differences between the two clones, the majority are located in the non-coding regions. Within the coding region there are 87 nucleotide differences but only three of these result in amino acid substitutions.
 ...
PMID:cDNA cloning of galectins from third stage larvae of the parasitic nematode Teladorsagia circumcincta. 920 Jan 21

Glutathione metabolism represents a potential target for anti-parasite drug design. The central role of glutathione reductase (GR) in maintenance of the thiol redox state and in anti-oxidative defence has to be evaluated in more detail in order to establish the essential function of this enzyme for the survival of the filarial parasite Onchocerca volvulus. The O. volvulus GR (OvGR) gene was cloned and sequenced. The gene is composed of 13 exons and 12 introns and spans 4065 bp. The first intron is located within the 5'-untranslated region of the gene, 16 nucleotides upstream of the translation initiation codon. Southern-blot analysis and structural characterization of the genomic sequence indicate that OvGR is encoded by a single-copy gene. Isolation of various cDNA clones revealed a polymorphism of polyadenylation initiation with no consensus polyadenylation sites in any of the cDNAs analysed. The entire cDNA is 1977 bp long and carries the nematode-specific spliced leader sequence SL1 at its 5' end, 236 nucleotides upstream of the first in-frame methionine. The cDNA codes for a polypeptide of 462 amino acids with 53.5% sequence identity with human GR (HsGR). A total of 18 out of 19 residues contributing to glutathione binding are identical in OvGR and HsGR. However, one of the arginine residues (Arg-224 in HsGR) involved in discrimination between NADPH and NADH in all known GRs is substituted by tryptophan (Trp-207 in OvGR). The coding region of OvGR was expressed in Escherichia coli as a histidine-fusion protein, and it was established that the parasite protein still favours the binding of NADPH (Km 10.9 microM) over NADH (Km 108 microM). The histidine-fusion protein has a subunit size of 54 kDa and is active as a homodimer of 110 kDa.
 ...
PMID:Molecular characterization and expression of Onchocerca volvulus glutathione reductase. 927 Oct 84