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At least 235 records · Page 13Linked to original sources
PubMed2006

Infection with the cestode Hymenolepis diminuta induces changes in acetylcholine metabolism and muscarinic receptor mRNA expression in the rat jejunum.

Total and neuron-specific uptake of [3H] choline into smooth muscle/myenteric plexus (SM/MP) preparations from the jejunum of rats infected with five Hymenolepis diminuta for 30 days compared to uninfected rats was significantly increased, as was choline acetyltransferase activity and acetylcholine biosynthesis. Although acetylcholinesterase and total cholinesterase activity levels in SM/MP preparations from infected rats were not significantly different from uninfected animals, pseudocholinesterase activity was significantly elevated in infected rats. Infection resulted in a significant elevation in the relative expression of muscarinic 2 (M2) receptor mRNA in jejunum compared to uninfected rats. Conversely, in rats infected with 50 worms for 30 days, the relative expression of muscarinic 1 (M1) receptor mRNA in the jejunum was significantly depressed, while the expression of M2 receptor mRNA was not significantly different from that in five worm infections. The relative expression of muscarinic 3 receptor mRNA was unaffected by infection. The present study shows that infection of rats with low numbers of an enteric cestode leads to a significant modulation of the cholinergic components of the myenteric plexus and M2 receptor mRNA, and that large number of worms result in suppression in the relative expression of M1 receptor mRNA.

Acetylcholine↗
PubMed2006

Spermiogenesis in the caryophyllidean cestode Khawia armeniaca (Cholodkovski, 1915).

Spermiogenesis of the monozoic cestode Khawia armeniaca (Cholodkovski, 1915), a parasite of Capoeta capoeta sevangi (De Filippi, 1865) (Pisces: Cyprinidae), has been investigated by means of transmission electron microscopy for the first time. The present results show that the type of spermiogenesis in K. armeniaca shares the main features described previously in the pseudophyllideans and/or spathebothriideans: apical dense material in the zone of differentiation in the early stages of spermiogenesis, rotation of flagellum and flagellar bud, proximodistal fusion, and penetration of the nucleus into the spermatid body after the fusion of the free flagellum with the MCP has started. However, only one axoneme and a simple intercentriolar body represent presumably more evolved characters, typical for "higher" tapeworms. Ultrastructural data of spermiogenesis in K. armeniaca may support the hypothesis that the Caryophyllidea are secondarily derived from an ancestor closely allied with the Pseudophyllidea.

Animals↗
PubMed2006

Spermatozoon ultrastructure of the pseudophyllidean cestode Paraechinophallus japonicus, a parasite of deep-sea fish Psenopsis anomala (Perciformes, Centrolophidae).

This paper provides the first ultrastructural data on the spermatozoon of a pseudophyllidean cestode belonging to the family Echinophallidae, Paraechinophallus japonicus, parasitizing deep-sea fish Psenopsis anomala from Japan. The mature spermatozoon contains two axonemes of the 9+"1" trepaxonematan pattern, nucleus, cortical microtubules, and electron-dense granules. Its anterior extremity exhibits a single electron-dense crested body. One of the most interesting features of the mature spermatozoon is the presence of a ring of tubular structures encircling the axoneme. This character, previously reported in species of the families Bothriocephalidae and Triaenophoridae, may be unique to pseudophyllideans of the group "Bothriocephalidea", thus supporting the assumption that the order Pseudophyllidea is formed in fact by two unrelated clades; "Bothriocephalidea" and "Diphyllobothriidea". The posterior extremity contains the posterior part of the nucleus and the disorganized axoneme--a character previously not described in the Eucestoda.

Animals↗
PubMed1996

Immunocytochemical localization of glutamate-like immunoreactivity within the nervous system of the cestode Mesocestoides corti and the trematode Fasciola hepatica.

The localization and distribution of glutamate-like immunoreactivity (IR) in the nervous system of both the cestode Mesocestoides corti and the trematode Fasciola hepatica has been determined by an indirect immunofluorescent technique, in conjunction with confocal scanning laser microscopy (CSLM). Immunostaining was widespread in the central (CNS) and peripheral (PNS) nervous systems of both species examined. In the CNS, IR was evident in nerve cells and fibres in the cerebral ganglia, the cerebral commissure and the dorsal, ventral and longitudinal nerve cords. In the peripheral nervous system (PNS) of M. corti, IR was apparent in nerve plexuses associated with the subtegmental musculature and the musculature associated with the anteriorly positioned suckers. In F. hepatica, IR was evident in the innervation of both the oral and the ventral suckers. In the reproductive system of F. hepatica, glutamate-IR was observed around the ootype/Mehlis' gland complex.

Animals↗
PubMed1999

Scolex morphology of the cestode Silurotaenia siluri (Batsch, 1786) (Proteocephalidae: Gangesiinae), a parasite of European wels (Silurus glanis).

The morphology of the scolex of the tapeworm Silurotaenica siluri (Batsch, 1786) (Proteocephalidae: Gangesiinae), a specific parasite of European wels (Silurus glanis L.), was studied using light, scanning (SEM), and transmission electron (TEM) microscopy. The scolex of S. siluri is rather uniform in shape and size; it is globular, and has four prominent, anteriorly directed suckers and a spherical, muscular apical organ corresponding to the rostellum of cyclophyllidean cestodes. The rostellum-like apical organ is armed with five to six irregular rows of small hooklets with a wide, oval basal plate and a short, posteriorly curved blade. The excretory system of the scolex is formed by sinuous secondary canals ending blindly beneath the distal layer of the tegument, not opening outside. The surface of the scolex is covered with filiform microtriches; giant spine-like and blade-like microtriches, incorrectly interpreted as spines or hooklets in previous descriptions of S. siluri, are present on the neck region and posterior margins and internal cavities of the suckers. It is assumed that tegumental spines reported in the scolices of other proteocephalideans (subfamilies Acanthotaeniinae and Gangesiinae, genera Spasskyellina and Nomimoscolex) could indeed be spiniform microtriches.

Animals↗
PubMed2005

Three new genera of trypanorhynch cestodes from Australian elasmobranch fishes.

Three new genera of trypanorhynch cestodes from Australian elasmobranch fishes collected in the Arafura Sea, off the Northern Territory, are described. Fossobothrium perplexum n. g., n. sp. (Otobothriidae), from the spiral valves of Anoxypristis cuspidata (Latham) and Pristis zijsron Bleeker, is similar to the otobothriid genera Pseudotobothrium Dollfus, 1942 and Poecilancistrium Dollfus, 1929 in possessing bothrial pits and a band of hooks on the tentacle, but differs from all known otobothriid genera in having the pits joined by a prominent velum. Iobothrium elegans n. g., n. sp. (Otobothriidae), from the spiral valve of Himantura jenkinsi (Annandale), is placed in the Otobothriidae because it possesses bothrial pits, but differs from Otobothrium Linton, 1890 and other genera in lacking intercalary hooks between the principal rows and in possessing a chainette on the external surface of the tentacle in the metabasal region. Oncomegoides celatus n. g., n. sp. (Eutetrarhynchidae), from the spiral valve of Dasyatis microps (Annandale) and Himantura jenkinsi, resembles Oncomegas Dollfus, 1929 in possessing two bothria and a megahook on the bothrial surface of the basal armature, but differs in possessing an extra row consisting of four intercalary hooks formed by the overlapping of two intercalary hooks on the external tentacular surface between each of the opposing principal rows and is therefore an atypical heteroacanth.

Animals↗
PubMed2005

Taxonomic revision of the cestodes of the family Progynotaeniidae (Cyclophyllidea) parasitising stone curlews (Charadriiformes: Burhinidae).

The type series of Progynotaenia evaginata Fuhrmann, 1909 from Burhinus senegalensis in Sudan, P. foetida Meggitt, 1928 from B. oedicnemus in Egypt and Angularia australis Maplestone, 1921 from B. grallarius in Australia are redescribed. As a comparative material, specimens of P. evaginata from B. oedicnemus in Kazakhstan were studied. The type-series of P. evaginata and P. foetida were found to be heterogeneous due to the presence of scoleces and fragments of cestodes of the genus Stenovaria Spasskii & Borgarenko, 1973 (Dilepididae). For P. foetida, a lectotype is designated. P. foetida is recognised as a synonym of P. evaginata (new synonymy). Angularia australis, previously considered a member of the Dilepididae, is transferred to the Progynotaeniidae as a synonym of P. evaginata (new synonymy). The synonymy of P. indica Johri, 1963 with P. evaginata, proposed by Ryzhikov & Tolkacheva (1981), is supported. The host range and the geographical distribution of P. evaginata are restricted to birds of the genus Burhinus from the Eastern Hemisphere.

Animals↗
PubMed2006

Gilquiniid cestodes (Trypanorhyncha) from elasmobranch fishes off New Caledonia with descriptions of two new genera and a new species.

Cestodes were collected from deep-sea sharks caught off New Caledonia, South Pacific. Vittirhynchus squali n. g., n. sp. (Trypanorhyncha: Gilquiniidae) is described from the spiral valve of Squalus melanurus Fourmanoir & Rivaton. The new genus possesses four bothria and a typical heteroacanthous metabasal armature but has a file of three macrohooks forming a short chainette on the internal surface of the basal armature. Sagittirhynchus aculeatus n. g., n. sp., from the spiral valve of Centrophorus sp. (undescribed), also has four bothria and a typical heteroacanthous armature but lacks a distinctive basal swelling and has the final hooks of each principal row prominently enlarged. Gilquinia minor n. sp., from the spiral valve of Centrophorus sp. (undescribed), is distinguished by the presence of only five hooks per principal row compared with eight in congeners. Gilquinia sp. is reported from Squalus melanurus. G. robertsoni Beveridge, 1990 is reported from S. megalops (Macleay).

Animals↗
PubMed1995

Characterisation of taeniid cestode species by PCR-RFLP of ITS2 ribosomal DNA.

Seven species of taeniid cestode (Echinococcus granulosus. E. multilocularis, Taenia hydatigena, T. ovis, T. pisiformis, T. multiceps and T. serialis) were characterised using a polymerase chain reaction-based restriction fragment length polymorphism technique (PCR-RFLP). The second internal transcribed spacer of ribosomal DNA (ITS2) was amplified from various geographical isolates of each of the seven species, digested separately with four restriction endonucleases and the fragments were separated by conventional agarose gel electrophoresis. PCR-RFLP produced characteristic patterns for each taeniid species examined. No variation in RFLP patterns was observed among different isolates of E. multilocularis and the species of Taenia, but distinct intraspecific variation was detected in E. granulosus. The present study indicates the usefulness of the PCR-RFLP of ITS2 for systematic, epidemiological and diagnostic purposes.

Animals↗
PubMed1991

Sphingolipids of a cestode Metroliasthes coturnix.

Sphingolipids of Metroliasthes coturnix were studied. The cestode contained no detectable amounts of sphingomyelin. The major glycosphingolipids found were monogalactosylceramide, galactosyl-alpha-1-4-galactosylceramide, galactosyl-beta-1-6-galactosyl-beta-1-6-galactosylceramide and galactosyl-beta-1-6-galactosyl-beta-1-6-galactosyl-beta-1-6-galactosylce ramide. Their ceramides were mostly composed of C18-20 sphinganine or 4-D-hydroxysphinganine, which is N-acylated by extraordinarily long normal and 2-hydroxy acids such as C26 acid (range C16 to C30) except tetragalactosylceramide. The structure of glycosphingolipids was confirmed after their chromatographic separation into each molecular species using a novel analytical device, fast atom bombardment-mass spectrometry linked with reversed-phase high-performance liquid chromatography.

Acylation↗
PubMed1990

Acetylcholine-like immunoreactivity in the cestode Hymenolepis diminuta.

The localization of acetylcholine in tissues of the cestode Hymenolepis diminuta was determined, following derivatization, using an antibody raised against choline-glutaraldehyde-protein. Specific immunoreactivity was observed in the rostellum and beneath the suckers of the scolex, in the longitudinal nerve cords, in cells adjacent to some deep longitudinal muscles, in the genital primordium, in the wall of the cirrus sac, and in the external and internal seminal vesicle. The distribution of acetylcholine-like immunoreactivity in relation to that of serotonin and glutamate, and the distribution of acetylcholinesterase in H. diminuta is discussed.

Acetylcholine↗
PubMed1995

A simple method for collecting eggs of taeniid cestodes from fresh, frozen or ethanol-fixed segments.

A simple method was devised for collecting eggs of Taenia taeniaeformis and T. saginata. All gravid segments, either fresh or frozen or 70% ethanol-fixed, were gently scraped using a pestle on a 150 mesh stainless steel sieve. Eggs and tissue debris were washed out all together with mouse tonicity phosphate buffered saline (MTPBS) through the 150 mesh sieve into a glass beaker. Egg suspension with a huge amount of tissue debris in MTPBS was centrifuged 5 min at 3000 r.p.m. (x 1600 g) and the pellet of eggs and tissue debris was resuspended with 1 vol. of MTPBS and 2 vol. of Percoll (Pharmacia) and centrifuged 60 min at 3000 r.p.m. More than 90% of eggs sedimented in the pellet. The supernatant covered with tissue debris was decanted, and the egg pellet was resuspended and centrifuged several times with MTPBS to remove Percoll. It is suggested that this simple method may prove useful for preparation of eggs of biohazardous taeniid cestodes, such as Taenia solium and Echinococcus spp.

Animals↗
PubMed1995

Neuropeptides and serotonin in the cestode, Proteocephalus exiguus: an immunocytochemical study.

Neuropeptides and serotonin in the cestode, Proteocephalus exiguus: an immunocytochemical study. International Journal for Parasitology 25: 673-682. Neuropeptide F (NPF), RFamide and serotonin (5-HT) immunoreactivities have been detected in the nervous system of P. exiguus procercoids and adults, using an indirect immunocytochemical technique in conjunction with confocal scanning laser microscopy. The peptidergic nervous system of the procercoid is well developed, with two brain ganglia, three pairs of longitudinal nerve cords, transverse ring commissures and nerves in the suckers, all showing NPF-immunostaining. Strong NPF- and RF-immunostaining was observed in the CNS and PNS of the adult worm. The distribution patterns of the two neuropeptides were similar. Immunoreactivity for 5-HT was found only in the CNS.

Animals↗
PubMed1994

Transberingian dispersal of cestodes in mammals.

During Pleistocene glaciations, eustatic lowering of sea-level exposed the continental shelf between northeastern Eurasia and northwestern North America. That land in combination with unglaciated areas on the adjacent continents formed a vast region open to the west but bounded on the east by continental ice. Organisms from Eurasia spread into the unglaciated Beringian refugium, which was biotically an eastward extension of the Palaearctic. With rising sea-levels following glacial periods, the Bering Strait was formed and organisms of Eurasian origin were left within the nearctic sector of Beringia. As the continental ice disappeared, plants and animals spread eastward and southward from Beringia, while organisms from beyond the southern margins of the ice extended their ranges northward. The significance of Beringia is discussed with reference to the dispersal of host-specific cestodes in mammals that attained holarctic status during the late Pleistocene.

Animals↗
PubMed1983

Thromboxane A2 generation by the larval cestode, Taenia taeniaeformis.

The larval stage of the tapeworm, Taenia taeniaeformis, was incubated in different concentrations of arachidonic acid. At various times after incubation, aliquots were removed for bioassay on either 38 microM aspirin or non-aspirin-treated equine platelets and by radioimmunoassay for the thromboxane A2 breakdown product, thromboxane B2 (TXB2). Platelet agonist activity was detected as early as 30 sec after addition of the arachidonic acid. In aspirin-treated platelets, this agonist activity peaked at 1 to 4 min and thereafter decayed rapidly with a time course that was both worm and arachidonic acid dependent. When assayed on non-aspirin-treated platelets the agonist activity was again detectable as early as 30 sec after addition of arachidonic acid, peaked at 1 to 3 min and then decayed very slowly over a 30-min period of incubation. It was found that levels of TXB2 were detected which increased over time concomitant with the decay of the platelet agonist activity. The most consistent detection of TXB2 generation was at 30 min with a mean of 49.6 pg and a range of 22.1 to 84.8 pg for four experiments. This report presents the first evidence for arachidonic acid utilization by a cestode or trematode and could in part provide an explanation for the marked cellular inflammation noted around dead or dying parasites.

Animals↗
PubMed1980

Lipids of stages in the life-cycle of the cestode Spirometra mansonoides.

The kinds and amounts of the lipids of each stage (egg, coracidium, procercoid, plerocercoid, adult) in the life-cycle of the cestode Spirometra mansonoides, and of environmental lipids, have been examined by combinations of TEAE-cellulose and silicic acid column, silica gel thin-layer and SCOT column gas-liquid chromatography. Major lipids of all stages were triacylglycerols, cholesterol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and phosphatidylcholine. Minor lipids were sterol esters, fatty acids, benzoquinones, partial glycerides phosphatidic acid, sphingolipids and lysolipids. Triacylglycerols decreased and cholesterol and phospholipids, particularly diphosphatidylglycerol and phosphatidylcholine, increased during embryogenesis (egg to coracidium). Neutral and phosphoglycerides had characteristic fatty acyl group patterns irrespective of life-cycle stage, except for procercoid lipids, which were unique in their content of branched and odd-numbered forms. The patterns seen in the total lipids of the various life-cycle stages were qualitatively similar to those of the environments of those stages, but were often quantitatively dissimilar.

Animals↗
PubMed1980

Benzoquinones in stages of the life-cycle of the cestode Spirometra mansonoides.

Ubiquinone-10 and rhodoquinone-10 were detected in stages of the life-cycle of a pseudophyllidean cestode, Spirometra mansonoides, by chromatographic, UV spectrophotometric, proton nuclear magnetic resonance spectrometric and electron impact mass spectrometric methods. Ubiquinone-10 was identified in 1-day-old eggs and coracidia, and rhodoquinone-10 in coracidia, plerocercoids and adult tapeworms. Tentative identification were also made of ubiquinone-10 in procercoids and rhodoquinone-10 in 10-day-old eggs. The roles of benzoquinones in helminth aerobic and anaerobic metabolism are discussed in relation to their distribution in stages of the S. mansonoides life-cycle.

Animals↗
PubMed1983

Ribonucleotide levels in six nematodes, a cestode and a trematode.

The levels of ribonucleotides in the nematodes Haemonchus contortus, Ostertagia circumcincta, Trichostrongylus colubriformis, Nippostrongylus brasiliensis, Ascaris suum and Stephanurus dentatus, the cestode Moniezia expansa and the trematode Fasciola hepatica were measured by high pressure liquid chromatography. The adenylate charge, ATP and total adenine nucleotide levels were in general agreement with those determined enzymatically and with published data. UDP and guanine nucleotide levels were found to be higher than those present in mammals and previously reported for helminth parasites. Cytidine nucleotide levels varied considerably between parasite species. On the other hand inosine nucleotides were present at low concentrations in all species. Adenylate and guanylate charges were similar.

Adenine Nucleotides↗