Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CESTODES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed1984

The occurrence of ecdysteroids in the cestode, Moniezia expansa.

The occurrence of free ecdysteroids in the sheep cestode, Moniezia expansa, was demonstrated. Significant amounts of conjugated ecdysteroids were not detected. Characterization of the free hormones by high-performance liquid chromatography monitoring fractions by radioimmunoassay, and by gas chromatography/mass spectrometry (selected ion monitoring) indicated the presence of ecdysone, 20-hydroxyecdysone and 20,26-dihydroxyecdysone. Analysis of the ecdysteroids by radioimmunoassay in segments along part of the strobila indicated that the anterior parts contained the greatest amount of hormone. GC/MS (SIM) analysis of the hormones in a strobilar segment containing the most mature proglottids suggested the presence of several ecdysteroid metabolites.

Animals↗
PubMed1994

Pyruvate dehydrogenase complexes from the equine nematode, Parascaris equorum, and the canine cestode, Dipylidium caninum, helminths exhibiting anaerobic mitochondrial metabolism.

The pyruvate dehydrogenase complex (PDC) has been purified to apparent homogeneity from 2 parasitic helminths exhibiting anaerobic mitochondrial metabolism, the equine nematode, Parascaris equorum, and the canine cestode, Dipylidium caninum. The P. equorum PDC yielded 7 major bands when separated by SDS-PAGE. The bands of 72, 55-53.5, 41 and 36 kDa corresponded to E2, E3, E1 alpha and E1 beta, respectively. The complex also contained additional unidentified proteins of 43 and 45 kDa. Incubation of the complex with [2-14C]pyruvate resulted in the acetylation of only E2. These results suggest that the P. equorum PDC lacks protein X and exhibits an altered subunit composition, as has been described previously for the PDC of the related nematode, Ascaris suum. In contrast, the D. caninum PDC yielded only four major bands after SDS-PAGE of 59, 58, 39 and 34 kDa, which corresponded to E3, E2, E1 alpha and E1 beta, respectively. Incubation of the D. caninum complex with [2-14C]pyruvate resulted in the acetylation of E2 and a second protein which comigrated with E3, suggesting that the D. caninum complex contained protein X and had a subunit composition similar to PDCs from other eukaryotic organisms. Both helminth complexes appeared less sensitive to inhibition by elevated NADH/NAD+ ratios than complexes isolated from aerobic organisms, as would be predicted for PDCs from organisms exploiting microaerobic habitats. These results suggest that although these helminths have similar anaerobic mitochondrial pathways, they contain significantly different PDCs.

Acetylation↗
PubMed1987

CTAB precipitation of cestode DNA.

DNA probes are proving extremely valuable in the characterization o f cestodes - as well as other parasites. In this article, Kok Wei Yap and Andrew Thompson discuss some of the problems of DNA isolation, stressing the need for a gentle and economical procedure such as CTAB precipitation.

Journal Article↗
PubMed1983

PGE2 generation and release by the larval stage of the cestode, taenia taeniaeformis.

The existence of an arachidonate cascade in invertebrate species has been little explored. We therefore sought to determine if two important prostanoid compounds, PGE2 and prostacyclin, PGI2 were generated and released by the larval stage of the cat tapeworm, Taenia taeniaeformis. PGE2 and PGI2 were identified by specific radioimmunoassay after thin layer chromatography of chloroform/methanol extracts of the worms or in vitro saline culture media. We detected a release of 176-182 pg of PGE2 from 2 worms after a 60' incubation at 37 degrees C with 4.5 mM exogenous sodium arachidonate. No release of PGI2 was detected immunochemically although 41 pg of immunoreactive material was identified in chloroform/methanol extracts of the worm alone. We therefore suggest that modulation of host immune responses could occur by the generation and release of prostanoid compounds such as PGE2, lipids which markedly suppress host cellular reactivity to the parasite. Secondly, the lack of any clot formation around the living organism may well reflect PGI2 presence at the surface of the parasite membrane. Although these findings are at present limited to larval cestodes we would propose that they may be more general means of evading host responses than heretofore suspected.

Animals↗
PubMed1984

The occurrence, synthesis and metabolism of 5-hydroxytryptamine and 5-hydroxytryptophan in the cestode Hymenolepis diminuta: a high performance liquid chromatographic study.

The biosynthesis and metabolism of 5-hydroxytryptamine (serotonin; 5-HT) in the cestode Hymenolepis diminuta was investigated by High Performance Liquid Chromatography (HPLC). Incubation of intact H. diminuta in [3H]tryptophan resulted in substantial radioactivity recovered in 5-HT, 5-hydroxytryptophan (5-HTP), and 5-hydroxyindoleacetic acid (5-HIAA). Furthermore, the tissue levels of 5-HT and 5-HTP, as determined by HPLC with electrochemical detection, were significantly depressed when the animals were deprived of tryptophan. On the other hand, the tissue levels of 5-HTP were significantly increased following incubation with the 5-HTP decarboxylase inhibitor m-hydroxybenzylhydrazine. The synthesis and metabolism of 5-HT are discussed in the light of 5-HT as a physiological transmitter in H. diminuta.

5-Hydroxytryptophan↗
PubMed1985

The uptake and metabolism of 5-hydroxytryptamine by tissue slices of the cestode Hymenolepis diminuta.

The in vitro uptake of [3H]5HT was investigated in tissue slices of the cestode Hymenolepis diminuta. A concentrative, sodium sensitive, high affinity uptake mechanism (Km 1.43 X 10(-6) M; Vmax 222 fmoles/mg wet wt/min), together with a sodium insensitive component (linear up to 5 X 10(-6) M) were present. In the presence of 2-nitroimipramine the sodium sensitive component was significantly suppressed (Vmax 33 fmoles/mg/wet wt/min) although the Km (1.37 X 10(-6) M) was not affected. Nitroimipramine showed an IC50 of approximately 2 X 10(-6) M. The sodium insensitive component was not affected by nitroimipramine. Biogenic amines and related indoleamines were weak inhibitors of the sodium sensitive and sodium insensitive components of 5HT uptake. The tricyclic antidepressants and fluoxetine were effective inhibitors of the sodium sensitive component of 5-HT uptake; receptor ligands were weak inhibitors or without effect. The metabolism of [3H]5HT in tissue slices of H. diminuta was examined by HPLC. The role of the sodium sensitive uptake and metabolism of 5HT in terms of inactivation and recycling of neurally released 5HT and the possible importance of exogenous recruitment of 5HT are discussed.

Animals↗
PubMed1986

The uptake and metabolism of L-glutamate by tissue slices of the cestode Hymenolepis diminuta.

The in vitro uptake of L-[3H]glutamate by tissue slices of the cestode Hymenolepis diminuta, denuded of tegument, was investigated. Two sodium concentration-dependent mechanisms, one of high affinity (Kt 1.8 X 10(-5) M; Vmax 4.76 pMoles/min/mg wet weight) and another of low affinity (Kt 2.2 X 10(-4) M; Vmax 50.7 pMoles/min/mg wet weight), were identified, in addition to a sodium insensitive component. Exchange of preloaded [3H]glutamate did not occur in tissue slices incubated in dilute unlabelled glutamate. Acidic amino acids, imipramine and fluoxetine were effective inhibitors of high and low affinity uptake, while glutamate receptor ligands, neurotransmitters and some antihelminthics generally were not. The concentrations present in, and the metabolism of glutamate by, tissue slices was examined by HPLC. The significance of the three modes of glutamate uptake and their possible role in the physiology of H. diminuta are discussed.

Amino Acids↗
PubMed2005

Echinococcus shiquicus n. sp., a taeniid cestode from Tibetan fox and plateau pika in China.

The taeniid cestode Echinococcus shiquicus n. sp. was found from the Tibetan fox Vulpes ferrilata and the plateau pika Ochotona curzoniae in the Qinghai-Tibet plateau region of China. In the adult stage, E. shiquicus from the foxes is morphologically similar to Echinococcus multilocularis. However, the new species is differentiated by its smaller rostellar hooks, fewer segments, distinct position of genital pore in the mature segment and fewer eggs in the gravid segment. Hydatid cysts of E. shiquicus found in the livers from the pikas were essentially unilocular but an oligovesicular cyst was also found. The data of mitochondrial and nuclear DNA sequences proved E. shiquicus to be a valid taxon.

Amino Acid Sequence↗
PubMed2005

Copro-DNA tests for diagnosis of animal taeniid cestodes.

PCR has proven its value for the diagnosis of taeniid cestodes in animal definitive hosts, although only few specific tests are available at the moment (Echinococcus multilocularis, Echinococcus granulosus 'sheep strain'). Additional tests with specificities for further taeniids are urgently needed and new tests are currently being developed, e.g. a multiplex PCR for simultaneous detection of E. multilocularis, E. granulosus (all strains) and Taenia spp. (all species). PCR is a technically demanding and expensive technique: DNA isolation from faecal specimens remains a laborious task because of the presence of PCR-inhibitory substances, and special precautions need to be taken to avoid false-positive results due to cross-contamination of amplification reactions. PCR, therefore, is mainly used for confirmative purposes of coproantigen-positive samples or for identification of taeniid eggs recovered from faecal specimens or from environmental samples.

Animals↗
PubMed1997

Differentiation and ultrastructure of the paruterine organs and paruterine capsules, in the nematotaeniid cestode Nematotaenia dispar (Goeze, 1782) Lühe, 1910, a parasite of amphibians.

Three types of egg-protecting envelopes of parenchymatic, uterine and embryonic origin have been distinguished in the cyclophyllidean cestode Nematotaenia dispar (Goeze, 1782) Lühe, 1910, a type species for the genus Nematotaenia and the family Nematotaeniidae. The present paper deals with the parenchymatic envelopes, which originate from the modified medullary parenchyma and are represented in this species by the paruterine organs and paruterine capsules. In pregravid proglottids they are composed of clongated myocytons, myofibrils and membranous anucleate cellular processes, containing a large amount of lipid droplets and some calcareous corpuscle cells. These cellular elements (CE) are separated from each other by abundant extracellular matrix (ECM), which consists primarily of an electron lucent ground substance with fine filaments embedded in it. The paruterine capsules of gravid proglottids are surrounded from the outside by a typical medullary parenchyma and are lined by a layer of the connective tissue. The paruterine organs and paruterine capsules show similar ultrastructure. During their histogenesis, all cellular elements undergo extensive flattening, followed by cellular deterioration, with simultaneous reduction in CE/ECM ratio. In the late gravid segments, paruterine capsule walls are very thick and consist of membranous sheets with large amounts of lipid droplets, which cause the cytoplasmic sheets to bulge. Ultrastructure of various types of parenchymatic envelopes in representatives of different cyclophyllidean families, such as paruterine organs in Nematotaeniidae and Mesocestoididae, uterine and parenchymatic egg capsules in Anoplocephalidae (Linstowiinae and Inermicapsiferinae, respectively), is compared.

Animals↗
PubMed1996

A chromosome study in the progenetic cestode Cyathocephalus truncatus (Cestoda:Spathebothriidea).

The chromosomes of somatic cells of progenetic Cyathocephalus truncatus, parasite of amphipod crustaceans, Gammarus lacustris, from North-West Chukotka were investigated using standard Giemsa staining. The karyotype, not described previously, consists of 9 pairs of chromosomes (2n = 18), the most widespread number among cestodes. A considerable number of polypoid cells (34.7%) was noted in preparations. The chromosomes are comparatively large, up to 12.26 microns. According to centromeric index values, chromosomes 1 and 4 subtelocentric; 2, acrocentric to subtelocentric; 3 and 5, acrocentric; 6 and 9, metacentric; 7 submeta-subtelocentric; and 8, submetacentric. These characteristics are discussed with reference to the karyotypes previously described within other closely related groups caryophyllideans and pseudophyllideans.

Animals↗
PubMed2003

Molecular cloning of genes encoding oncosphere proteins reveals conservation of modular protein structure in cestode antigens.

Recombinant oncosphere antigens have been found to be remarkably effective when used as vaccines against cysticercosis and hydatid disease. Comparison of the structural features of these proteins and their associated genes suggest common features between antigens. Here molecular cloning is used to complete comparisons of Taenia solium, Taenia saginata, Taenia ovis, Echinococcus granulosus and Echinococcus multilocularis oncosphere antigens and genes. The exon/intron structure of genes cloned from T. solium and T. ovis genomic DNA (tsol16 and to16, respectively) in this study was found to be highly conserved. Two closely related tsol16 genes were cloned from the T. solium genome. Their corresponding transcripts were cloned from T. solium oncospheres and a comparison of their deduced amino-acid sequence with that of the protein encoded by to16 indicates that these proteins are the most highly conserved oncosphere proteins identified so far. Cloning of another gene from T. solium (designated tsol18) and comparison with the homologous gene of T. saginata (tsa18) also revealed substantial conservation of gene structure. Comparisons of the genes cloned in this study with genes encoding oncosphere antigens from other taeniid cestodes identified striking conservation of exon structure. The highly conserved regions of the genes encode a putative secretory signal and fibronectin type III domain in each of the oncosphere proteins. The location of exon boundaries in relation to protein features identifies a clear modular structure among all members of these oncosphere antigens. Identification of structural conservation of genes encoding antigenic proteins across several taeniid species suggests that the encoded proteins play important roles in host infection and parasite survival.

Animals↗
PubMed1996

Cestodes. Echinococcus.

This article deals with cystic echinococcosis (CE) and alveolar echinococcosis in humans caused by the cestode parasites Echinococcus granulosus and Echinococcus multilocularis. The life cycles of these parasites and their epidemiologic aspects are briefly discussed, and a detailed review is presented on clinical aspects of the diseases, including diagnosis and therapy. Considerable progress has been made in chemotherapy but the results are not yet satisfactory. A new alternative for treatment of CE is puncture of cysts, aspiration of fluid, injection of ethanol, and reaspiration of fluid (PAIR).

Animals↗
PubMed1998

A novel Na+/HCO3--codependent choline transporter in the syncytial epithelium of the cestode Hymenolepis diminuta.

Absorption of exogenous choline by the cestode Hymenolepis diminuta was found to be both Na+- and HCO3--dependent and, at pH 6 to 7, accounted for up to 65% of the total choline uptake. Na+/HCO3- dependent choline uptake was activated at approximately 6 mM HCO3- (EC50 approximately 9 mM), and, above 100 mM Na+, the rate of uptake was directly proportional to the Na+ concentration. Atempts to uncouple Na+-dependent uptake from HCO3--dependent uptake were not successful: K+-depolarization was without effect on HCO3--dependent choline uptake, and use of valinoomycin to hyperpolarize the brush-border membrane resulted in inhibition of uptake. Na-/HCO3--dependent choline uptake was not associated with solvent drag. The Na+/HCO3--dependent choline uptake displayed a Q10 of 6.4 (27 degrees to 37 degrees) and a relatively high activation energy of 126 kJ x mol(-1). At pH 6.0 and 7.0, Na-/HCO3--dependent choline uptake rates were similar, but Na+/HCO3--dependent choline uptake was reduced at pH 5.0. The Na+/HCO3--dependent choline uptake, at pH 7.0, displayed a Kt of approximately 500 microM and a Vmax of 4.01 pmol x mg wet weight(-1) x min(-1). The Na+/HCO3--dependent choline uptake was hemicholinium-3 sensitive, but not significantly inhibited by 200 microM bumetanide, 100 microM amiloride, benzamil, or EIPA or by 1 mM 4,4'-diisothiocyano-2,2'-stilbene disulfonate (DIDS) or 4-acetamido-4'-isothiocvanostilbene-2,2'-disulfonic acid (SITS). Although it remains to be shown that HCO3- uptake is coupled directly to both choline and Na+ uptake, the data suggest that choline up take occurs via choline/Na+/HCO3--co-trans porter.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2001

Phylogenetic identification of Sparganum proliferum as a pseudophyllidean cestode by the sequence analyses on mitochondrial COI and nuclear sdhB genes.

Sparganum proliferum is a larval cestode for which the adult stage is unknown. It is characterized by the continuous branching and budding when parasitized to humans, and causes fatal human sparganosis. However, the biological features of S. proliferum, including its taxonomic status, still remain obscure. Our previous investigation suggested that S. proliferum might be phylogenetically distinct from Spirometra erinaceieuropaei, by the analysis on mitochondrial NADH dehydrogenase subunit 3 (ND3) gene. However, mitochondrial DNA sequence in Platyhelminth is known to have heteroplasmy within a species. Therefore, in the present study, we have investigated the complete nucleotide sequences of mitochondrial cytochrome c oxidase subunit I (COI) gene and the partial nucleotide sequences of nuclear coded succinate dehydrogenase iron-sulfur protein subunit gene (sdhB). The results clearly demonstrated that S. proliferum is a distinct species from S. erinaceieuropaei, and that S. proliferum belongs to the order Pseudophyllidea.

Amino Acid Sequence↗
PubMed2003

Anthelmintic efficacy of Flemingia vestita (Fabaceae): Effect of genistein on glycogen metabolism in the cestode, Raillietina echinobothrida.

The edible root-tuber peel of Flemingia vestita and its major active component, genistein, have been earlier shown to have a vermifugal/vermicidal effect on cestodes in vitro by causing a flaccid paralysis and alterations in the tegumental architecture and activity of several enzymes associated with the tegumental interface of the parasite. Pursuing further investigation on the mode of action of this putative anthelmintic, the crude peel extract and pure genistein were further tested in respect of glycogen metabolism in the fowl tapeworm, Raillietina echinobothrida. On exposure to the plant root peel crude extract (5 mg/ml) and genistein (0.2 mg/ml), the glycogen concentration was found to decrease by 15-44%, accompanied by an increase of activity of the active form of glycogen phosphorylase (GPase a) by 29-39% and decrease of activity of the active form of glycogen synthase (GSase a) by 36-59% in treated parasites as compared to untreated controls, but without affecting the total activity (a+b) of both the enzymes. Praziquantel (1 microg/ml), the reference drug, also caused quantitative reduction in glycogen level and alterations in enzyme activities somewhat at par with the genistein treatment. These results suggest that this plant-derived component may influence the glycogen metabolism of the parasite by directing it towards utilization of glycogen.

Animals↗
PubMed2002

The complete mitochondrial DNA sequence of the cestode Echinococcus multilocularis (Cyclophyllidea: Taeniidae).

The 13,738 bp mitochondrial DNA from the cestode Echinococcus multilocularis has been sequenced. It contains two major noncoding regions and 36 genes (12 for proteins involved in oxidative phosphorylation, two for rRNAs and 22 for tRNAs) but a gene for ATPase subunit 8 is missing. All genes are transcribed in the same direction. Putative secondary structures of tRNAs indicate that most of them are conventional clover leaves but the dihydrouridine arm is unpaired in tRNA(Ser(AGN)), tRNA(Ser(UCN)), tRNA(Arg) and tRNA(Cys). The base composition at the wobble positions of fourfold degenerate codon families is highly biased toward U and against C.

Journal Article↗