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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytoplasmic malate dehydrogenase from ovine liver Echinococcus granulosus protoscolices was purified 22-fold by QAE- and SP-Sephadex chromatography. The pH optimum of the enzyme was 8.0 in either Tris-HCI or barbital buffer. The Km values of oxaloacetate and NADH were 0.400 +/- 0.018 and 0.410 +/- 0.038 mM, respectively. The enzyme lost about 90% of its activity when heated for 2 min at 65 degrees C. A 61.4% inhibition of the enzyme was noted at 4 mM concentration of diethyl pyrocarbonate. A 3 mM concentration of fructose 1,6-diphosphate inhibited the enzyme by 76.5%. The inhibition was non-competitive with respect to NADH with a Ki value of 0.85 mM. A 75% inhibition of the enzyme was noted at 1 mM concentration of mebendazole that inhibited the enzyme upon competing with NADH with a Ki value of 0.176 mM. A 2-mM concentration of citrate almost doubled the enzyme activity. The enzyme was inhibited at high concentrations of either substrate. The enzyme was not inhibited by p-hydroxymercuribenzoate or fumarate. The enzyme was absolutely specific for NADH as a cofactor. The properties of this enzyme are compared with those of the enzyme from the host liver, the cyst fluid and some other animal sources. The results are discussed in terms of the differences among the properties of the host liver, the cyst fluid and the protoscolices enzymes. The biochemical basis for the use of mebendazole in the treatment of echinococcosis is also elucidated.
Comp Biochem Physiol B Biochem Mol Biol 1996 Apr
PMID:Partial purification and kinetic properties of cytoplasmic malate dehydrogenase from ovine liver Echinococcus granulosus protoscolices. 892 42

Infection by the tapeworm Echinococcus granulosus in the intermediate host results in the development of a hydatid cyst which contains the protoscoleces within a fluid-filled cavity enclosed by the bilayered cyst membrane. N-glycans were enzymatically released from crude extracts of homogenates of hydatid cyst membranes and protoscoleces and their structures were defined by high sensitivity fast atom bombardment mass spectrometry in conjunction with sequential exoglycosidase digestions. The major N-glycans from the cyst membrane were found to be non-charged structures having complex-type antennae and core fucosylation. The antennae are either truncated at the first N-acetylglucosamine or are extended with beta-galactose to form N-acetyllactosamine (lacNAc). A significant proportion of the lacNAc backbones are capped by alpha-galactose. The resulting Gal alpha-Gal beta-terminal structures may account for the earlier observation that antibodies against the blood group P1 epitope recognise components of hydatid cyst extracts. The complex-type N-glycans identified in the protoscoleces extracts were the same as the neutral structures found in the cyst membrane but a small proportion of high mannose structures and truncated di- and trimannosyl core structures were also identified. Sialylated N-glycans were identified as minor constituents of the cyst membrane preparation but were not observed in protoscoleces extracts. Whether the sialylated glycans are host derived or endogenously synthesized by the parasite remains to be established. This is the first reported structural analysis of N-glycans from cestodes and provides new insights into protein glycosylation in helminths.
Mol Biochem Parasitol 1997 Jun
PMID:Structural characterization of the N-glycans from Echinococcus granulosus hydatid cyst membrane and protoscoleces. 920 Jan 29

We have isolated a cDNA from the hydatid tapeworm, Echinococcus granulosus, encoding a protein that binds laminin. This is the first report of a helminth parasite laminin-binding protein and the first description of a cDNA encoding a laminin-binding protein from a parasite. The cDNA clone (egmo3) was isolated from an E. granulosus protoscolex cDNA expression library, and identified on the basis of sequence homology to the nonintegrin mammalian metastasis-associated 67-kDa laminin receptor (67-LR). The amino acid sequence predicted from the cDNA sequence is 268 residues long with a calculated molecular mass of 29.9 kDa. Southern blot analysis suggested that many copies of the gene may occur in the E. granulosus genome. A Northern blot revealed that the gene is expressed as a single transcript of approximately 1 kb consistent with the size of the cDNA insert. Antibodies raised to the purified protein interacted with a 30 kDa protein in whole E. granulosus protoscoleces. A Western blot of the purified and refolded recombinant protein specifically bound 125I-labelled laminin, as did a synthetic peptide derived from the inferred amino acid sequence of egmo3 which is similar in homology to peptide G, the active ligand-binding site of 67-LR. We also isolated the 3' end of the cDNA encoding the homologous protein from the closely related species, E. multilocularis. The polypeptide encoded by egmo3 also shares substantial identity with the acidic class of ribosomal proteins which are involved in protein synthesis. As such, the egmo3 protein may be multifunctional in E. granulosus, acting as a laminin-binding molecule but also playing a role in cell division and growth.
Mol Biochem Parasitol 1997 Aug
PMID:Cloning and expression of a cDNA encoding a nonintegrin laminin-binding protein from Echinococcus granulosus with localization of the laminin-binding domain. 924 29

A cDNA expression library representing the metacestode developmental stage of the tapeworm Echinococcus multilocularis was immunoscreened with monospecific antibodies affinity purified following differential immunoblot analysis. Using this procedure, a metacestode-specific clone was isolated representing a 14-3-3 gene of the parasite, which is present as a single copy in the parasite genome. The identity of this clone was demonstrated by cross-reactivity of the recombinant E. multilocularis 14-3-3 protein with antibodies raised against a heterologous 14-3-3 protein from Saccharomyces cerevisiae. In addition, expression of the E. multilocularis 14-3-3 gene in the mutant S. cerevisiae strain, DS9-22, resulted in complementation of the phenotypic deficiency of this strain, thus demonstrating the functionality of the respective gene product. By reverse transcription-polymerase chain reaction (RT-PCR) we showed that the E. multilocularis 14-3-3 protein is about 10-fold overexpressed in the metacestode stage compared with the expression level in the adult stage. Immunolocalization of the 14-3-3 protein in E. multilocularis metacestodes revealed its predominant presence in the germinal layer of the parasite. The results of this study, taken together with the current knowledge on the 14-3-3 protein family, suggest that this parasite molecule may contribute to the promotion of the progressive, potentially unlimited growth behaviour of the E. multilocularis metacestode within the host tissue.
Mol Biochem Parasitol 1998 Mar 15
PMID:Stage-specific expression of the 14-3-3 gene in Echinococcus multilocularis. 956 21

EgDf1 is a developmentally regulated protein from the parasite Echinococcus granulosus related to a family of hydrophobic ligand binding proteins. This protein could play a crucial role during the parasite life cycle development since this organism is unable to synthetize most of their own lipids de novo. Furthermore, it has been shown that two related protein from other parasitic platyhelminths (Fh15 from Fasciola hepatica and Sm14 from Schistosoma mansoni) are able to confer protective inmunity against experimental infection in animal models. A three-dimensional structure would help establishing structure/function relationships on a knowledge based manner. 3D structures for EgDf1 protein were modelled by using myelin P2 (mP2) and intestine fatty acid binding protein (I-FABP) as templates. Molecular dynamics techniques were used to validate the models. Template mP2 yielded the best 3D structure for EgDf1. Palmitic and oleic acids were docked inside EgDf1. The present theoretical results suggest definite location in the secondary structure of the epitopic regions, consensus phosphorylation motifs and oleic acid as a good ligand candidate to EgDf1. This protein might well be involved in the process of supplying hydrophobic metabolites for membrane biosynthesis and for signaling pathways.
J Comput Aided Mol Des 1998 Jul
PMID:Modelling a 3D structure for EgDf1 from Echinococcus granulosus: putative epitopes, phosphorylation motifs and ligand. 977 93

The activities of the enzymes in Echinococcus multilocularis metacestodes involved in purine salvage were studied by HPLC. As in most parasites, this cestode relies entirely on salvage of preformed bases and nucleosides for its purine requirement. Therefore, these enzymes may be targets for drugs in the chemotherapeutic treatment of diseases caused by this parasite. The animals used in this study were gerbils (Meriones unguiculatus). Enzyme activities from sera and hepatic tissue in control and infected animals were similar with the exception of adenine phosphoribosyltransferase which showed an activity 4-fold greater in the serum from control than in serum from infected animals. In the parasite, adenine and hypoxanthine-guanine phosphoribosyltransferases and adenosine deaminase had the highest activities. Therefore, in E. multilocularis metacestodes, this pathway seems to be important for the parasite's metabolism.
Comp Biochem Physiol B Biochem Mol Biol 1998 Aug
PMID:Purine metabolism in Echinococcus multilocularis. 985 10

A 314-bp fragment of the mitochondrial 12S rRNA gene from 21 cestodes species of eight families was synthesized by PCR with specially designed primers. These allowed amplification of parasite DNA without concomitant synthesis of host DNA. Phylogenetic trees were inferred from the sequence data using three methods (maximum parsimony, maximum likelihood, and Fitch-Margoliash). At the major nodes all three trees were similar. For the first time the genus Mesocestoides could be arranged into the Cyclophyllidea and a narrow relationship between the Mesocestoididae, Taeniidae, Hymenolepididae, Anoplocephalidae, and Dipylidiidae was shown. Members of the families Catenotaeniidae and a cluster of two families (Hymenolepididae and Dilepididae) form two monophyletic groups which derive prior to the remaining families of this phylogenetic study. A third and a fourth clear monophyletic group were formed by the Taeniidae and by the Mesocestoididae. A high degree of variation within the examined 304-bp fragment was observed between two isolates of Taenia taeniaeformis, supporting often discussed genetic heterogeneity within this species. In contrast, only one nucleotide exchange was found in 23 isolates of Echinococcus multilocularis of various geographic origin, indicating that this species is genetically homogenous.
J Mol Evol 1999 May
PMID:Contributions to the phylogeny of the Cyclophyllidea (Cestoda) inferred from mitochondrial 12S rDNA. 1019 24

An immunoscreening of a cDNA library derived from the adult stage of the parasitic platyhelminth Echinococcus granulosus has been carried out with sera from infected dogs. The EgA31 clone encodes a fibrous protein which shares some sequence elements with paramyosins. The corresponding gene is present as a single copy in the genome. As revealed by an antibody obtained against a fusion protein produced in bacteria, the polypeptide has a molecular weight of 66 kDa. This polypeptide is present at all developmental stages studied and is a potent antigen during an infection by the adult stage in the dog and during cyst growth in human patients. By immunohistology, it was shown that it is present in the tegument and subtegumental parenchyma of the adult with a main location in the region of the suckers where it rapidly accumulates at the time of the head evagination. It is also present in the germinal layer of the cyst and on the protoscolex.
Mol Biochem Parasitol 1999 Jul 30
PMID:A new potent antigen from Echinococcus granulosus associated with muscles and tegument. 1047 75

In this work the characterization of P-29, a novel 29 kDa antigen from Echinococcus granulosus is reported. E. granulosus was identified while looking for parasite antigens distinct from those present in hydatid cyst fluid. A monoclonal antibody (mAb 47H.PS) prepared against protoscolex components revealed that P-29 is localized to the tegument and rostellum of protoscoleces, and to the germinal layer of the cyst, but it is absent in hydatid cyst fluid or adult worm extracts. Several internal fragments of P-29 showed sequence identity to the amino acid sequence encoded by Eg6, a partial gene sequence reported to code for an epitope of antigen 5 (Ag5), one of the major diagnostic antigens of the parasite. We confirmed that Eg6 encodes a sub-fragment of P-29 by mapping the epitope of mAb 47H.PS, and isolating the full length P-29 cDNA. Since Eg6 had been, postulated to encode a fragment of Ag5, we specifically studied the relationship of P-29 and Ag5 by: (i) examining the cross-reactivity displayed by different mAbs; (ii) comparison of their peptide finger prints; and (iii) a comparative study of their diagnostic value. Our results prove unequivocally that P-29 and Ag5 are immunologically related, but different proteins, raising several questions on the current knowledge of Ag5.
Mol Biochem Parasitol 2000 Feb 05
PMID:Molecular characterization of P-29, a metacestode-specific component of Echinococcus granulosus which is immunologically related to, but distinct from, antigen 5. 1069 41

The flatworm mitochondrial genetic code, which has been used for all species of the Platyhelminthes, is mainly characterized by AUA codon for isoleucine, AAA codon for asparagine and UAA codon for tyrosine. In eight species of cestodes (Echinococcus multilocularis, Echinococcus granlosus, Taenia solium Taenia saginata, Taenia hydatigena, Taenia crassiceps, Hymenolepis nama and Mesocestoides corti), the cytochrome c oxidase subunit I (COI) genes were partially sequenced to verify this genetic code. Comparison of the COI-encoding nucleotide sequences with those of human, sea urchin, fruit fly, nematode and yeast indicated that the assignments of AUA and AAA codons are adequate for cestodes. In addition, the nucleotide sequences of ATPase subunit 6 (ATP6) gene and its flanking region were compared to examine initiation and stop codons. In the related species of T. solium and T. saginata, the deduced amino acid sequences of ATP6 were homogeneous; however, the conversion of initiation codon AUG into GUG was observed in T. saginata. We also found the similar conversion in T. crassiceps. The C-terminal sequences of putative ATP6 proteins were highly conserved among the eight species and the stop codon UAG was altered to UAA in all Taenia species. The features of the gene-junctional region between NADH dehydrogenase subunit 4 (ND4) and glutamine tRNA (tRNAGln) genes also supported that UAA serves as a stop codon. Based on these results, we propose that the flatworm mitochondrial code should be modified for cestodes, particularly, in an initiating methionine codon (GUG) and a terminating codon (UAA).
Mol Biochem Parasitol 2000 Dec
PMID:Mitochondrial genetic code in cestodes. 1116 47


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