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PubMed2001

Biochemical characterisation of a hydrophobic ligand binding protein from the tapeworm Hymenolepis diminuta.

The cestode Hymenolepis diminuta contains an abundant, cytoplasmic, hydrophobic ligand, binding protein (H-HLBP). Studies with polarity sensitive probes suggest a single hydrophobic binding site, the results also indicate that the single tryptophan in the molecule (Trp41) is involved in ligand binding. Of the possible physiological ligands tested, only haematin and retinoids (retinol and retinoic acid) show appreciable binding in addition to fatty acids. H-HLBP also binds a range of anthelmintics, again with K(D) values in the nM range. The interaction of anthelmintics with hydrophobic binding proteins may be important in determining drug specificity and site of action and could have a role in the development of drug resistance.

Animals↗
PubMed2003

Detection of the rodent tapeworm Rodentolepis (=Hymenolepis) microstoma in humans. A new zoonosis?

A longitudinal survey of gastro-intestinal parasites was conducted over a 3-year period in remote communities in the north-west of Western Australia where, based on diagnosis by microscopy of faecal samples, Rodentolepis (=Hymenolepis) nana was found to be the most common enteric parasite. In the present study, using molecular tools, we describe the unexpected discovery, of a mixed infection with a second hymenolepidid species, Rodentolepis (=Hymenolepis) microstoma in four of the surveyed individuals. In the absence of any reliable earlier reports we believe this is to be the first instance of the detection of R. microstoma from human hosts. The development of a diagnostic restriction fragment polymorphism has enabled the study of R. microstoma in human populations and will greatly facilitate a more thorough understanding of the epidemiology of this parasite in the future.

Animals↗
PubMed2003

Identification and characterisation of two distinct Smad proteins from the fox-tapeworm Echinococcus multilocularis.

Members of the transforming growth factor-beta (TGF-beta) family of cytokines and their corresponding receptors regulate cellular key processes such as proliferation and differentiation, and could be involved in communication mechanisms between parasitic helminths and their hosts. A pivotal role in intracellular TGF-beta signalling is played by Smad factors which directly transmit incoming signals from the cell surface receptors to the nucleus. In this study, we have identified and characterised two novel members of the Smad family, EmSmadA and EmSmadB, which are expressed by the human parasite Echinococcus multilocularis. Based on amino acid sequence comparisons, both echinococcal Smad homologues could be classified as members of the R-Smad subfamily. EmSmadB showed a typical domain structure consisting of conserved MH1 and MH2 domains separated by a proline-rich linker region. EmSmadA, on the other hand, lacked an MH1 region and merely contained an MH2 domain, a feature which has so far not been described for R-Smads. Based on the structures of the corresponding chromosomal loci and on sequence features of the conserved L3 loop regions, EmSmadA and EmSmadB are most likely involved in the transmission of TGF-beta- and bone morphogenetic protein (BMP) signals, respectively. Yeast two-hybrid analyses revealed that both Echinococcus Smads are capable of homo- and heterodimer formations. However, while the formation of homodimers for EmSmadB required previous activation of the protein at the C-terminal SSVS motif, EmSmadA homodimers were already formed in the basal state of the factor. Upon expression of the Echinococcus Smads in human cells, EmSmadA, but not EmSmadB, was phosphorylated by the human TGF-beta type I receptor. Furthermore, both factors functionally interacted with human BMP receptors. By reverse transcriptase-PCR experiments, the encoding genes, emsmadA and emsmadB, were shown to be expressed in the larval stages metacestode and protoscolex during an infection of the intermediate host. Taken together, our data suggest an involvement of EmSmadA and EmSmadB in echinococcal developmental processes during natural infections and provide a solid basis for further investigations on TGF-beta signalling mechanisms in cestodes.

Amino Acid Sequence↗
PubMed1977

Localization of alkaline and acid phosphatase activity in the intestine of healthy breams (Abramis brama l.) and those infected with plerocercoid of tapeworm Ligula intestinalis (Linné 1758).

The examination included 40 breams 4 to 7 years old (18 infected and 22 uninfected). Alkaline and acid phosphatase activity, as shown by the azo-coupling method, has been localized in the oesophagus and the intestine, being the strongest in the epithelium. It was distinctly less intensive in the Lamina propria mucosae and in the intermuscular connective tissue of the oesophagus, in the submucosa, in the cells of AUERBACH plexus and in the blood vessel walls. Besides only the acid phosphatase activity was noted in single (sometimes rather numerous) spherical cells - visible within the epithelium and Lamina propria mucosae. The cells are known as the components of so called "yellow bodies" (melanine macrophage centers) entering particular numerously in the spleen and in the pronephric kidney of infected breams. The activity of both enzymes in the epithelium was considerably weaker in the last third of the intestine, and none in cloaca and in Tunica muscularis all over the length of the intestine (and oesophagus) except for some cells of the connective tissue separating the layers of muscle fibres. No perceptible differences in the activity and localization of both enzymes in the intestine were observed between infected and uninfected fishes examined in different seasons of the year.

Acid Phosphatase↗
PubMed1998

Sparganosis of brain and spinal cord: unusual tapeworm infestation (report of two cases).

Among the diseases due to cerebral parasitism, those caused by sparganum mansoni, the larval form of Spirometra mansoni, are very rare. We report two cases, one involving the frontoparietal area in a 38-year-old male and presenting as a mass lesion and another in a 10-year-old girl, presenting with paraparesis due to mid-thoracic compressive mass lesion. Pathological examination of the resected lesion revealed the characteristic plerocercoid larva, spargana, enclosed in acute inflammatory exudate, resembling an abscess. Postoperative recovery was good, suggesting that the best treatment for cerebral or spinal sparganosis mansoni is surgical excision. Serological tests for diagnosis were not carried out in these cases, since parasitic infection was not suspected. Although generally the role of immunodiagnosis is limited due to rarity of the condition, in endemic areas such tests may be useful in preoperative diagnosis.

Adult↗
PubMed1978

Tapeworms of the Chaco Boreal, Paraguay, with two new species.

Mathevotaenia paraguayae sp. n. is described from Euphractus sexcinctus. It differs from M. didelphidis (Rud.) in having a transverse cirrus pouch anterior to the vagina. Monoecocestus mackiewiczi sp. n. was found in Phyllotis sp. It differs from M. parcitesticulatus Rego in having a much smaller scolex, a poral ovary, and a cirrus pouch 360 to 440 micrometers long. Other species reported are Taenia macrocystis, Taenia omissa, Spirometra mansonoides, Spirometra gracilis, Spirometra longicollis, Diphyllobothrium trinitatis, Atriotaenia parva, and Mathevotaenia tetragonocephala.

Animals↗
PubMed1991

Partial purification and characterization of a soluble acid phosphatase from the tapeworm, Hymenolepis diminuta.

An acid phosphatase activity (APA; EC 3.1.3.2) was demonstrated in homogenates of adult Hymenolepis diminuta. The APA was soluble based on the observation that it did not sediment at 130,000 g. APA was partially purified using a combination of differential centrifugation, ammonium sulphate precipitation, chloroform extraction, and gel and fast-protein-liquid-chromatography. This combination of techniques resulted in a preparation with a specific activity approximately 500 times greater than the crude enzyme preparation. The temperature and pH optima of the partially purified APA were 44 degrees C and pH 5.0. The enzyme appeared to be a monomer with a molecular weight of approximately 62,000. APA had a higher affinity for a greater activity towards aromatic than aliphatic phosphoesters, and phosphoryl transferase activity was demonstrable using 1-butanol and ethylene glycol as acceptors. APA was inhibited significantly by sodium dodecyl sulphate, fluoride, molybdate and tartrate, but CuSO4 and Fast Garnet GBC were poor inhibitors. The precise cellular localization and function of this enzyme remains unknown since it possesses characteristics of both cytoplasmic and lysosomal APA's of other organisms.

Acid Phosphatase↗
PubMed1984

Chemotaxonomic studies on davaineid tapeworms, based on amino acid analysis.

Twelve amino acids were detected in six davaineid cestodes, Davainea hewetensis Dhawan & Capoor (1972) collected from one Gallus gallus domesticus L. at Allahabad, India. Chemotaxonomic studies within the family Davaineidae have shown the presence of cystine and hydroxyproline only in D. hewetensis, although phenylalanine and proline occur in all species examined previously.

Amino Acids↗
PubMed1986

Immunity to tapeworms: acquired resistance to Hymenolepis citelli in the mouse.

The dynamics of secondary infections with Hymenolepis citelli in mice are described. A primary infection of one and six cysticercoids for 21 days sensitized CFLP male mice against homologous challenge infections. Acquired resistance was manifested mainly as stunting/destrobilation of secondary worms. The severity of stunting depended on the intensity of the primary infection. Secondary worms were not expelled more rapidly than primary worms but the protective response retards growth early in challenge infections. Sensitization of mice for seven days with six or 24 cysticercoids did not confer a measurable protective response, whereas priming by the same regime for 21 days induced a significant protective response. Acquired resistance to challenge waned with time in the absence of the primary worms. The growth and survival of a six-cysticercoid primary infection was enhanced by the administration of the immunosuppressant drug cortisone acetate. Worms from cortisone-treated mice were heavier than those from untreated controls. Acquired resistance to homologous challenge was also partially ablated in cortisone-treated mice. It is suggested that rejection of primary infections and stunting/destrobilation of secondary worms may be immunologically mediated.

Animals↗
PubMed1976

Tapeworms from Philippine birds, with three new species of Raillietina (Raillietina).

13 species of cestodes from 13 species of Philippine birds are reported from Palawan Island. Raillietina (R.) palawanensis n. sp., from Chalcophaps i. indica, has three or four testes, and a cirrus pouch 93 to 108 mum long, 28 to 45 mum wide, and its egg capsules are 10 to 12 mum long, seven to nine mum wide, each containing four to six eggs. Raillietina (R.) passeriformicola n. sp., from Gracula religiosa palawanensis, has seven to nine testes, and a cirrus poucch 134 to 170 mum long, 47 to 68 mum wide. Its egg capsules are 79 to 115 mum wide, containing 7 to 12 eggs each. Raillietina (R.) fischthali n. sp., from Ducula aenea palawanensis, has 12 to 15 testes, and a cirrus pouch 130 to 150 mum long, 52 to 72 mum wide. Its egg capsules are 130 to 200 mum wide each containing 50 to 70 eggs. Raillietina (R.) johri Ortlepp, 1938, is redescribed. Anonchotaenia chauhani Mukherjee, 1965 is shown to be a junior synonym of A. gaugi Singh, 1952.

Animals↗