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At least 145 records · Page 8Linked to original sources
PubMed2004

The phylogeny of diphyllobothriid tapeworms (Cestoda: Pseudophyllidea) based on ITS-2 rDNA sequences.

Phylogenetic analysis of sequences of the ITS-2 rRNA genes of 20 samples of pseudophyllidean cestodes of the family Diphyllobothriidae (Ligula, Digramma, Diphyllobothrium, and Schistocephalus) from different hosts and geographical regions revealed that: (1) the inclusion of ligulids (previously family Ligulidae) to the Diphyllobothriidae is correct; (2) Schistocephalus appears as the most basal taxon of the Diphyllobothriidae, well separated from Ligula and Digramma, thus supporting the validity of Schistocephalinae Dubinina, 1962; (3) Digramma belonged with samples of Ligula, thus suggesting its invalidity as a genus; and (4) isolates of Ligula, presumably belonging to Ligula intestinalis, are paraphyletic, indicating that this species may represent a complex of separate taxa. Our results indicate the necessity for a taxonomic revision of the family Diphyllobothriidae.

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PubMed2004

Cadmium and lead concentrations in Gallegoides arfaai (Cestoda: Anoplocephalidae) and Apodemus sylvaticus (Rodentia: Muridae) from Spain.

Information on parasites of vertebrates living in terrestrial ecosystems as sentinels for heavy metal environmental pollution is scarce. The aim of the present study was to assess the concentration of cadmium and lead using the model Apodemus sylvaticus/Gallegoides arfaai in order to test the potential suitability of G. arfaai as a sentinel organism for lead and cadmium under natural field conditions. Samples of 15 A. sylvaticus as well as whole specimens of G. arfaai were analysed for both elements by inductively coupled plasma mass spectrometry. The level of cadmium in G. arfaai was always much lower than in the tissues of A. sylvaticus. Contrarily, values for lead in G. arfaai were found to be 6, 20 and 24-fold higher than in the kidney, liver and muscle of A. sylvaticus. We propose the model A. sylvaticus/G. arfaai as a promising bioindication system to evaluate environmental lead exposure in terrestrial habitats, especially for non-urban areas.

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PubMed2005

First record of Progrillotia dasyatidis Beveridge Neifar and Euzet, 2004 (Cestoda: Trypanorhyncha) plerocerci from Teleost fishes off the Portuguese coast, with a description of the surface morphology.

Plerocerci of Progrillotia dasyatidis Beveridge et al. (2004), family Progrillotiidae Palm (2004), are reported from several teleost fishes off the Portuguese coast, giving a first insight into the life cycle biology of these unique trypanorhynchs. The first description and assignment of the plerocercus to P. dasyatidis is based on morphological features, such as scolex and bothria morphology and tentacular hook arrangement, and is expanded to incorporate the surface morphology, examined by scanning electron microscopy, constituting the first ultrastructural study for a species within this family. Comparisons with other species of the genus Progrillotia are made, based on the scolex and bothria morphology and tentacular hook arrangement, in order to give an overview into the variability within this genus, whereas comparisons with adults from the same species evidence the variability within the same species. The systematic approaches of Campbell and Beveridge (1994) and Palm (1997, 2004) are discussed and emphasis is placed on the utility of microtriches and the characteristic life cycle within the genus as systematic characters.

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PubMed2005

Transmission electron microscopy of the scolex and neck microtriches of Silurotaenia siluri (Batsch, 1786) (Cestoda: Proteocephalidea).

Microtriches on different parts of the scolex and neck of the gangesiine cestode Silurotaenia siluri (Batsch 1786) were studied. The neodermis of the central frontal scolex part (around the rostellar furrow) bears filamentous microtriches only. The lateral frontal part and the parts between and posterior to the suckers cover filamentous and spine-like microtriches. Within the suckers there are short spine-like microtriches with bases enforced by electron-dense ribs. The proximal neck part bears filamentous and spine-like microtriches, the middle part solitary distributed blade-like and spine-like microtriches among filamentous ones, and the distal part blade-like microtriches. The functions of different types of microtriches are discussed.

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PubMed2007

Genetic markers to distinguish Moniezia expansa from M. benedeni (Cestoda: Anoplocephalidae) and evidence of the existence of cryptic species in Australia.

Multilocus enzyme electrophoresis (MEE) was used to genetically compare Moniezia spp. collected from sheep and cattle in southern Australia. Fifteen enzyme loci were established for the genetic characterisation of individual specimens of Moniezia, which represents a significant increase in the number of loci that was previously available for these cestodes. Another four enzyme loci were also identified as providing potential genetic markers. There were no differences in staining activity or banding patterns of different body regions of individual cestodes. Fixed genetic differences between Moniezia expansa and Moniezia benedeni were detected at 10 (77%) loci. Individuals that lacked the diagnostic morphological characters (i.e. the arrangement pattern of the interproglottidal glands) could be assigned to either morphospecies based on their MEE profiles. Genetic differences were also detected among individuals of the two morphospecies. One specimen of M. expansa had fixed genetic differences at 33% of enzyme loci when compared to all other specimens of M. expansa. Fixed genetic differences were also detected between the two groups of M. benedeni at 12 of 13 (92%) enzyme loci. This magnitude of genetic difference was greater than that detected between the two morphospecies. This provides evidence for the existence of cryptic species in the genus Moniezia.

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PubMed2000

Ultrastructure studies of preadult Proteocephalus longicollis (Cestoda, Proteocephalidea): transmission electron microscopy of scolex sensory receptors.

The ultrastructure of five types of presumed sensory receptors in the scolex of preadults of Proteocephalus longicollis is described. Two types of nonciliate sensory receptors are situated on the inner surface of the lateral sucker. They differ from each other in the shape, presence, or absence of a large rootlet, electron-dense collars, desmosomes, microtubules, and/or vesicles. In addition, three types of ciliate sensory receptors are found along the edges of the lateral suckers. They can be differentiated by the length of the cilium, by the number of electron-dense collars (one or two), and by types of vesicles. Four types of vesicles were found inside the ciliate sensory receptors. One type of ciliate sensory receptor occurring in preadults differs markedly from any of the sensory receptors previously described in adult P. longicollis.

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PubMed1996

Intraspecific variability of Proteocephalus exiguus La Rue, 1911 (Cestoda: Proteocephalidae) as studied by the random amplified polymorphic DNA method.

The intraspecific variability of Proteocephalus exiguus, a common fish cestode, was studied by the random amplified polymorphic DNA method. Isolates from four distant localities and four host species were investigated using eight arbitrary decamer oligonucleotides as primers. A relatively high variation of RAPD fingerprints from individual strobila was detected. The constant fragments observed in all isolates detected by eight primers characterized the species studied.

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PubMed1996

A total DNA characterization in Proteocephalus exiguus and P. percae (Cestoda: Proteocephalidae): random amplified polymorphic DNA and hybridization techniques.

Two morphologically similar fish tapeworms, Proteocephalus exiguus and P. percae, were differentiated by the random amplified polymorphic DNA (RAPD) marker and Southern-blot hybridization techniques. Four geographic isolates of P. exiguus and two of P. percae were studied using eight arbitrary decamer oligonucleotides as primers. Species-specific RAPD fragments enabled reliable separation of the taxa studied. Generally, 1-3 fragments specific for P. percae and 1-4 P. exiguus-specific fragments were detected using individual primers. Intraspecific differences in P. percae depended on the primer used. The profiles generated by the primers OPA 04 and OPA 12 showed an intraspecific variation, whereas six other primers tested revealed indistinguishable banding patterns. On the other hand, intraspecific variability of P. exiguus, detected among four geographic isolates, was evident using all primers. Additionally, the utilization of two species-specific RAPD markers as effective probes was demonstrated. Distinct differences between P. exiguus and P. percae were revealed using each of the restriction enzyme/probe combinations.

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PubMed1997

Ultrastructure of the spermatozoon of Dipylidium caninum (Cestoda, Cyclophyllidea, Dilepididae), an intestinal parasite of Canis familiaris.

We report for the first time the ultrastructure of the spermatozoon of a Dilepididae cestode. The mature spermatozoa of Dipylidium caninum is filiform and tapered at both ends and lacks mitochondria. The anterior extremity exhibits an apical cone of electron-dense material measuring about 600 nm in length and a single helicoidal crested-like body that is 150 nm thick. This single crested-like body is spiralized at an angle of about 40 degrees to the spermatozoon axis. The axoneme, showing the 9 + "l" pattern of the Platyhelminthes, lacks a periaxonemal sheath. The cortical microtubules constitute a continuous, submembranous, electron-dense material, and they are also twisted at an angle of about 40 degrees to the spermatozoon axis. Moreover, the nucleus is coiled in a helix around the axoneme, which is centrally located throughout its length. We demonstrate for the first time the presence of peripheral microtubules twisted to the spermatozoon axis up to the posterior extremity of the gamete.

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PubMed1998

Surface ultrastructure of plerocercoids of Bombycirhynchus sphyraenaicum (Pintner, 1930) (Cestoda: Trypanorhyncha).

Light microscopy studies have previously shown that Bombycirhynchus sphyraenaicum is an exceptional trypanorhynch cestode, characterised by a poeciloacanthous armature and two enormous bothridia, which overlap parts of the pars bulbosa, a character combination unique within the trypanorhynchs. Plerocercoids of B. sphyraenaicum from the fish Lates calcarifer (Centropomidae) were investigated by scanning and transmission electron microscopy. Results revealed that the tegument of the anterior margin of the distal bothridial surface bears three kinds of microtriche; palmate microtriches, 8 microns high, with seven to eight digitiform processes; equalized filamentous microtriches, 5-6 microns long, with cap and base each forming 50% of the length, borne on undulations beneath the palmate microtriches, and cap-dominated filamentous microtriches, 5-6 microns long, with the cap forming 75% of the length, borne on the apex of putative sensory papillae. Integumental connections link the bases of the palmate microtriches, forming transverse girdles around the worm, which may serve to coordinate traction. At regular intervals between the palmate microtriches are papillae, covered with filamentous microtriches extending above the palmate microtriches. A cilium emerges from a bulb at the apex of each papilla; other structures in the bulb include an electron-dense cuff, and two electron dense collars. The posterior part of the bulb tapers and passes into the tegumental cytoplasm. These adorned papillae, observed for the first time in trypanorhynch cestodes, are identified as putative mechanoreceptors.

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PubMed1998

Ultrastructure of the spermatozoon of the bank vole tapeworm, Paranoplocephala omphalodes (Cestoda, Cyclophyllidea, Anoplocephalidae).

The mature Paranoplocephala omphalodes spermatozoon is filiform, tapered at both ends and lacks mitochondria. Its anterior extremity exhibits an apical cone of electron-dense material measuring about 900 nm in length and 200 nm in width, and two crested-like bodies. The cortical microtubules follow a 25-35 degrees helicoidal path along their whole length, except at the posterior extremity where they become parallel to the spermatozoon axis. They are arranged in a single or two fields which may cover each other partially. The axoneme, of the 9 + "1" pattern of the Trepaxonemata, lacks a peri-axonemal sheath and does not reach the extremity of the spermatozoon. The nucleus is a compact and irregular cord coiled in a spiral around the axoneme. Moreover, we report for the first time a nucleus in the spermatozoon of a Cyclophyllidea species which reaches beyond the axonemal posterior extremity. The cytoplasm, depending on the level where the section is cut, is slightly electron dense or electron lucent and contains numerous small electron-dense granules in regions III-V. In the posterior spermatozoon extremity, granular material is replaced by a terminal and compact electron-dense material.

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PubMed1999

Tegumental topography of the plerocercoid of Gymnorhynchus gigas (Cestoda : Trypanorhyncha).

The tegumental topography of the plerocercoid of Gymnorhynchus gigas is described for the first time. The surface features were examined by scanning electron microscopy. Eight different types of microthrix pattern were found. Differences in the shape and density of microtriches depend on their location. A unique morphological feature is reported herein, namely, filamentous microtriches that were arranged in clusters with a dome-shaped pattern when the bothridial surface was relaxed but sunk into a crater when the bothridial surface was contracted. In contrast to other trypanorhynchan cestodes, palmate microtriches are not found on the tegument of this plerocercoid. The microtriches on the caudal extension gradually increased in length with growing distance from the blastocyst, which showed short knob-like structures. These structures developed into elongated filiform microtriches on the posterior region of the caudal extension.

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PubMed1999

A chromosome study of the tapeworm Bathybothrium rectangulum (Bloch, 1782) (Cestoda: Pseudophyllidea).

The diploid number 2n = 18 was revealed in Bathybothrium rectangulum, a specific parasite of barbels (Barbus spp.). All chromosome pairs were biarmed (pairs 1, 4, 7, 8, and 9 were metacentric; pairs 2, 3, and 6 were meta-submetacentric; and pair 5 was submetacentric) and small (from 1.49 to 2.95 microm). The C-banding method revealed pericentromeric heterochromatin in pairs 1, 3, 5, and 7; distinct C-bands in pairs 2, 4, 8, and 9; and a slight band in short arms of pairs 1 and 6. The karyotype of B. rectangulum is discussed with respect to the irresolute taxonomic position of B. rectangulum within the Pseudophyllidea.

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PubMed1999

Ultrastructural study of the papillae and presumed sensory receptors in the scolex of the Gymnorhynchus gigas plerocercoid (Cestoda: Trypanorhyncha).

The ultrastructure of the papillae and presumed sensory receptors in the tegument of the scolex of Gymnorhynchus gigas plerocercoid were investigated by scanning and transmission electron microscopy. Four distinct types of putative sense receptor (including three uniciliated and one nonciliated) are described for the first time in G. gigas, and this investigation is the first detailed ultrastructure study of tegumental receptors carried out in trypanorhynch cestodes. Microtriches arranged in clusters with a dome-shaped pattern seemed to be papillae that contained a ciliated sensory receptor (type I). The density of these papillae was greater in the center of the bothridial adherent surface near the tentacle orifice than in the lateral margins of the bothridia or in the pars post-bothridialis. The type I receptor is characterized by a long cilium anchored in the nerve bulb by a dense basal body but lacks rootlets. The bulb contains one or two electron-dense collars, numerous electron-lucent neurovesicles, and some mitochondria. The type II receptor presents a short cilium retracted into an invagination of the tegument that arises from the basal body. The bulb contains one electron-dense collar and numerous electron-lucent vesicles, but the rootlets are absent. The type III receptor is also a ciliated receptor embedded in a bulb wider than that of types I and II, and it differs from type II in that it possesses two electron-dense collars and small rootlets associated with the basal body. No electron-lucent vesicle was found in the bulb of this type III receptor. The type IV receptor is a nonciliated receptor localized under the surface with no contact to the outside. It consists of a flattened bulb that contains two electron-dense collars and striated rootlets associated with a band of microfilaments. A comparison of the ultrastructural features of receptors in different cestodes is presented.

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PubMed2005

Clestobothrium gibsoni n. sp. (Cestoda: Bothriocephalidae) from the bullseye grenadier Bathygadus macrops Goode & Bean (Macrouridae) in the Gulf of Mexico.

Clestobothrium gibsoni n. sp. is described from the intestine of the bullseye grenadier Bathygadus macrops (Macrouridae) collected in the northeastern Gulf of Mexico. The new species can be distinguished from both C. crassiceps (Rudolphi, 1819), the type-species of the genus, and C. neglectum (Lönnberg, 1893), the second species in the genus, by its unique ovary, which is transversely elongate and tapered on both ends rather than being U-or H-shaped, and by having more testes (60-65 vs 40-50 and 35-45 per proglottid). The new species is also compared to Bothriocephalus acheilognathi Yamaguti, 1934 and B. kivuensis Baer & Fain, 1954, two species with similar scoleces which have previously been assigned to Clestobothrium . The generic diagnosis of Clestobothrium is amended to include species with either anoperculate or operculate eggs. This is the first report of an adult tapeworm from a species of Bathygadus , and the first report of a species of Clestobothrium Lühe, 1899 (Bothriocephalidae) from the Gulf of Mexico.

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PubMed2005

Aploparaksis demshini n. sp. (Cestoda: Hymenolepididae), a parasite of the woodcock Scolopax rusticola Linnaeus, and its life-cycle.

Aploparaksis demshini n. sp. is described from a woodcock Scolopax rusticola L. from different parts of the Palaearctic (Lithuania, Karelia, the Urals, Primorskiy Kray). It differs from the most similar species A. belopolskajae Bondarenko, 1988, a parasite of snipes Gallinago spp., in the form and length of the rostellar hooks and the smaller cirrus, and from two other similar species, A. clavata Spasskaya, 1966 and A. schilleri Webster, 1955, by having an embryophore with polar thickenings and a spindle-shaped cirrus. The life-cycle of the parasite was studied under experimental conditions. The metacestodes were commonly located under the chlorogogenous tissue of the intestine of the earthworms Eisenia foetida(Savigny), Dendrobaena octaedra (Savigny) and E. nordenskioldi(Eisen), and in the wall of the intestine of the enchytraeid Briodrilus arcticus(Bell). The metacestodes exhibit a pattern of postembryonal development typical for the cysticercoid modification termed an 'ovoid diplocyst'.

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PubMed2005

Redescription of Houssayela sudobim (Woodland, 1935) (Cestoda: Proteocephalidea), a parasite of Pseudoplatystoma fasciatum (Pisces: Siluriformes) from the River Amazon.

The proteocephalidean cestode Houssayela sudobim (Woodland, 1935), the type and only species of Houssayela Rego, 1987, is redescribed on the basis of re-examination of its type-specimens and freshly collected material found in the intestine of the barred sudobim Pseudoplatystoma fasciatum (Siluriformes: Pimelodidae) from the River Amazon in Peru. The validity of the genus is confirmed, but its diagnosis is amended because suckers possess four pairs of cone-shaped (papilla-like) projections on their anterior margins (rather than 16, as reported in the original description), the actual number of testes is more than 400 in a proglottis (not 150 as given by Woodland, 1935) and the vitelline follicles form one dorsolateral medullary band and one lateral cortical band on both sides of proglottides. In addition, the distal (terminal) portion of the vagina has a double sphincter and the cirrus-sac has very thick walls; neither of these characteristics was mentioned in the original description. The specimen collected in Peru represents the first record of the species since its original description in 1935.

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PubMed2005

Redescription of Cetorhinicola acanthocapax Beveridge & Campbell, 1988 (Cestoda: Trypanorhyncha) from the basking shark Cetorhinus maximus (Gunnerus).

Cetorhinicola acanthocapax Beveridge & Campbell, 1988 is redescribed based on adult specimens collected from a basking shark Cetorhinus maximus (Gunnerus) off the east coast of New Zealand. Both the mature and gravid segments are described for the first time, and the first scanning electron micrographs of the armature and scolex microtriches are provided. Novel features include the opening of the vagina anterior to the cirrus-sac and the extension of the vagina anterior to the cirrus-sac. Pectinate microtriches are present on the anterior quarter of the pars pedunculus scolecis scattered between filiform microtriches; the bothrial margins are covered with tridigitate microtriches, while the adherent surface of the bothria have pectinate microtriches. The additional morphological features described are consistent with a close association between Cetorhinicola Beveridge & Campbell, 1988 and the Eutetrarhynchoidea Guiart, 1927.

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