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At least 271 records · Page 15Linked to original sources
PubMed1994

The morphology of hymenolepidid and dilepidid cestodes from common and pygmy shrews (Soricidae) in southeast England.

One hundred and six of 109 common shrews (Sorex araneus) and 62 of 72 pygmy shrews (S. minutus), obtained by Longworth trapping in Southeast England, were infected with cestodes. Ten species were recovered: Choanotaenia hepatica and Hymenolepis prolifer (found in S. araneus); Choanotaenia crassiscolex, Hymenolepis furcata, H. jacutensis, H. schaldybini, H. scutigera, H. singularis, H. diaphana and H. infirma (in both hosts). The morphology, taxonomy and ecology of these species are discussed and the findings of the present study are discussed with reference to previous studies of the helminth fauna of British shrews. Cysticercoids of C. crassiscolex were found in the snail, Vitrina pellucida, and cysticercoids of H. schaldybini in the staphylinid beetle, Anthobium unicolor.

Animals↗
PubMed1976

The cellular response of the fowl small intestine to primary and secondary infections of the cestode Raillietina cesticillus (Molin).

Infections of Raillietina cesticillus in the small intestine of the fowl caused a mononuclear leucocyte infiltration, which occurred in the tissues around the worm scolices and was especially prevalent in challenge infections. There was no evidence of vascular congestion or of a neutrophilic response, and the cellular reaction seemed to consist of a local proliferation of lymphoid tissue. Mast cell and pyroninophylic cell numbers increased in the intestinal mucosa of birds with longstanding primary infections and with secondary infections, but very little eosinlophil infiltration was detected and the globule leucocyte response was minimal. The infections had no effect on the numbers of theliolymphocytes and goblet cells. Challenge infections did not result in an increased level of serum antibodies, but more cells containing globulin seemed to be present in the intestinal mucosa of these birds. The interrelationships of the various cell responses to the cestode and the origin of the globule leucocyte are discussed in the light of previous work on helminth infections.

Animals↗
PubMed1976

Molecular structure and morphology of glycogen isolated from the cestode, Moniezia expansa.

A particulate polysaccharide was isolated by differential centrifugation and alkali extraction from homogenates of the cestode Moniezia expansa. The polysaccharide had the structure of a glycogen. Its chemical properties, infra-red spectrum and optical rotation showed that it consisted of alpha-1,4- and alpha-1,6-linked glucopyranose units. Examination of the complex with iodine and the precipitate with concanavalin-A showed that the structure was highly branched. Oxidation with periodate and hydrolysis with alpha- and beta-amylase were used to measure mean chain lengths. For the particulate preparation the average chain length was 12-9 glucose units and the exterior and interior chain lengths were 9-0 and 2-9 units respectively. The particulate preparation had a very high sedimentation constant (s20, w = 910) with a smaller component at about s20, w = 600, but the alkali extracted material had an s20, w = 61 similar to that shown by alkali degradation of the particulate preparation. The morphology of the particulate material was similar to that of rat liver glycogen, alpha, beta- and possible gamma-particles being identified by electron microscopy. The alpha-particles were relatively stable under acidic conditions remaining intact down to pH 2-5. At pH 1-7 the alpha-particles dissociated into their constituent beta-particles with a consequent decrease in the opalescence of the solution. The nitrogen content of 0-9% was high for a glycogen.

Amylases↗
PubMed1987

Occurrence and biochemical characteristics of cestode lymphocyte mitogens.

The cestodes Echinococcus granulosus, Taenia multiceps, T. pisiformis, T. hydatigena, Hymenolepis diminuta, Moniezia expansa and Anoplocephala perfoliata all produced substances that stimulated thymidine incorporation by whole blood lymphocyte cultures. This mitogenic activity was demonstrated in metacestode cyst fluids, live protoscoleces and scoleces, parasite culture supernatants, and extracts of adult parasites. T. multiceps metacestode cyst fluid mitogen adhered to, but would not pass through, cellulose dialysis tubing. This adherence was reduced or prevented by D-glucose and by proteins. The mitogen was weakly anionic. With Sephadex G75 gel filtration, its elution volume was greatly decreased when the elution buffer contained 0.5 M D-glucose. Mitogenic activity was protease resistant and could be separated by gel filtration from all the cyst fluid proteins.

Animals↗
PubMed1987

Interspecific characterization of several taeniid cestodes by isoenzyme analysis using isoelectric focusing in agarose.

Taenia cestodes were obtained from 5 different definitive host species in Kenya and 175 different samples were examined by classical morphological methods and by isoenzyme analysis using isoelectric focusing in agarose. Gels were stained for 17 different enzymes and 3 of these were used in the construction of isoenzyme profiles. The samples fell into 25 zymodemes, and no zymodeme contained more than 1 species of Taenia, indicating that isoenzyme analysis can reliably be used for the identification of species of this genus.

Animals↗
PubMed2003

Genetic differentiation in populations of the cestode Bothriocephalus acheilognathi (Cestoda, Pseudophyllidea) as revealed by eight microsatellite markers.

The genetic structure of populations of the fish cestode, Bothriocephalus acheilognathi collected from Bailianhe Reservoir (BLH), Changshou (CSH) and Liangzi (LZH) Lakes was investigated by using 8 microsatellite loci. A total of 108 adult worms were genotyped at each of the 8 loci. For the 3 populations, the mean number of alleles per locus ranged from 2.38 to 5.5, and the mean expected heterozygosity ranged from 0.432 to 0.559. The average polymorphic information content (PIC) was from 0.384 to 0.492. The significant Fis values indicated non-random mating within LZH and BLH populations. On the other hand, when samples were further classified into subpopulations at the level of host fish species, no or little heterozygote deficiency was detected at most loci, showing that cross-fertilization, predominantly, but not exclusively, must have occurred within the subpopulations. Microsatellite markers also revealed an unexpected high level of genetic differentiation, as measured by R(st) and N(m) values or by delta(u)2 genetic distance among subpopulations from different hosts. Factors influencing the population genetic structure and the parasite host specificity are discussed.

Alleles↗
PubMed1997

The infectivity, growth, and virulence of the cestode Schistocephalus solidus in its first intermediate host, the copepod Macrocyclops albidus.

In an experiment to study the infectivity, growth and virulence of Schistocephalus solidus in their first intermediate host, copepods of the species Macrocyclops albidus were kept singly and exposed to up to 9 coracidia. Eleven or 14 days post-infection (p.i.) the presence and growth of the cestode larvae relative to survival, growth and reproduction of their host was determined. As expected, the probability of a copepod becoming infected increased with increasing numbers of parasites administered. However, the chances of a single coracidium establishing in a copepod also increased with increasing numbers of coracidia administered, which indicates that the parasites profit from a dilution effect of the host's defence. Copepod size or developmental stage had no significant effect on the infection, but 14 days p.i., constraining effects of copepod size on the growth of the parasites were apparent. Moreover, procercoids in multiple infections grew smaller and developed their cercomer at a smaller size than those in single infections. No significant effect of the parasite on host mortality was found within the observation period. However, growth between the 5th copepodid stage and adult stage was negatively affected by infection. An infection with S. solidus was also strongly linked with host reproduction: infected females were more likely to bear an egg sac at the end of the experiment than non-infected ones. These egg sacs, however, contained fewer eggs.

Analysis of Variance↗
PubMed1999

Antibody response of carp, Cyprinus carpio to the cestode, Bothriocephalus acheilognathi.

The humoral antibody response and the number of pronephric antibody-secreting cells were examined in naturally Bothriocephalus acheilognathi-infected carp. Cyprinus carpio, and in those injected intraperitoneally with an extract of the cestode. In the extract-injected fish, specific antibody was detected 3 weeks after a second injection given 2 weeks after the primary injection, and antibody levels persisted for more than 200 days. A third injection also enhanced the antibody level in the extract-injected carp. The numbers of antibody-secreting cells were significantly higher in carp injected 3 times with the extract than in the control. In naturally-infected fish, the serum antibody levels and the number of pronephric antibody-secreting cells were higher in infected fish than in uninfected individuals although this difference was not statistically significant. The relevance of these results to immune protection against infection is discussed.

Animals↗
PubMed1977

Studies on immune responses to larval cestodes in mice. Increased susceptibility of certain mouse strains and hypothymic mice to Taenia taeniaeformis and analysis of passive transfer of resistance with serum.

Various inbred strains of mice vary markedly in their susceptibility to the larvae of the cestode, Taenia taeniaeformis. Males are generally more susceptible than females and the most susceptible common inbred mouse strains are those which are deficient in C5 and/or C4 components of complement. However, no genetic evidence is yet available to implicate loci controlling complement levels in susceptibility/resistance, and multiple genetic factors appear to be operative. Hypothymic, nu/nu ("nude") mice of the relatively resistant mouse strain, BALB/c, are highly susceptible in that cystic larvae in the liver develop in large numbers and more rapidly than in intact BALB/c.nu/+litter-mates. Cyclophosphamide pretreatment also increases the susceptibility of relatively resistant strains of mice in terms of both the number and size of liver cysts. Hypothymic and intact mice can be protected, absolutely, by an injection of serum from infected intact mice, provided the serum is given to recipient mice close to the time of oral egg administration. The protective activity of immune serum is absorbed totally by staphylococcal protein A-Sepharose columns and can be abolished by treatment of recipients with cobra venom factor. Cyst fluid from established larvae facilitates the activity of subhaemolytic amounts of guinea pig complement in a standard direct PFC assay. The data suggest that complement-fixing antibodies are responsible for inhibition of establishing larvae in mice and that one method of protection for established cystic larvae involves the alteration of host complement activity within the cyst.

Age Factors↗
PubMed1980

Hybridoma antibody immunoassays for the detection of parasitic infection: attempts to produce an immunodiagnostic reagent for a larval taeniid cestode infection.

Attempts have been made to produce discriminatory immunodiagnostic reagents for infections of sheep with the larval stages of Taenia hydatigena, Taenia ovis and Echinococcus granulosus. Using cells from mice hyperimmunized with T. hydatigena antigenic preparations for fusion, a hybridoma antibody which bound to T. hydatigena larval antigens, but not to T. ovis or E. granulosus larval antigens, was selected. A competitive radioimmunoassay using the labelled hybridoma antibody and a crude parasite antigen mixture was devised as an immunodiagnostic test for experimental T. hydatigena infection. Sera from sheep exposed to 1000 or more T. hydatigena eggs were unequivocally positive but sera from 2 sheep with a monospecific infection with T. ovis were also positive. Sera from E. granulosus-infected sheep were negative and, although the numbers of sera involved were small, such discrimination has not been achieved by previous serologic methods. The discussion emphasizes various difficulties which have been encountered in the development of highly sensitive as well as specific hybridoma-based immunodiagnostic reagents for the detection of larval cestode infections in sheep.

Animals↗
PubMed2002

myo-Inositol hexakisphosphate is a major component of an extracellular structure in the parasitic cestode Echinococcus granulosus.

myo-Inositol hexakisphosphate (IP(6)) is an abundant intracellular component of animal cells. In this study we describe the presence of extracellular IP(6) in the hydatid cyst wall (HCW) of the larval stage of the cestode parasite Echinococcus granulosus. The HCW comprises an inner cellular layer and an outer, acellular (laminated) layer up to 2 mm in thickness that protects the parasite from host immune cells. A compound, subsequently identified as IP(6), was detected in and purified from an HCW extract on the basis of its capacity to inhibit complement activation. The identification of the isolated compound was carried out by a combination of NMR, MS and TLC. The majority of IP(6) in the HCW was found in the acellular layer, with only a small fraction of the compound being extracted from cells. In the laminated layer, IP(6) was present in association with calcium, and accounted for up to 15% of the total dry mass of the HCW. IP(6) was not detected in any other structures or stages of the parasite. Our results imply that IP(6) is secreted by the larval stage of the parasite in a polarized fashion towards the interface with the host. This is the first report of the secretion of IP(6), and the possible implications beyond the biology of E. granulosus are discussed.

Animals↗
PubMed1995

A novel lipid-binding protein from the cestode Moniezia expansa.

A lipid-binding protein (LBP) has been purified from the cytosol of the cestode Moniezia expansa. The native LBP was found to be an oligomer of approx. 250 kDa, consisting of 11 kDa monomers. The LBP bound saturated and unsaturated fatty acids, but not their CoA derivatives, with KD values in the range 0.68-7.8 microM. Cholesterol, dihydroergosterol, bilirubin and retinoids were also bound, but alpha-tocopherol, bile acids, alk-2-enals and alka-2,4-dienals were not. Evidence suggests that there are two binding sites per subunit, each with different specificities. The fluorescent fatty acid 11-[(5-dimethylaminonaphthalene-1-sulphonyl)amino]undecanoic acid (DAUDA) and retinol both showed an additional high-affinity binding site with a density of approximately 0.1 per subunit, suggesting specific binding to the oligomer. The amino acid composition of Moniezia LBP was distinct from that of previously characterized fatty acid-binding proteins (FABPs). The protein was not N-terminally blocked and yielded a unique amino acid sequence, unrelated to that of any known FABP; there was also evidence of microheterogeneity. Polyclonal antibodies raised to the Moniezia protein did not cross-react with mammalian, nematode or digenean FABP. The Gibbs free energy for protein folding (13.02 kJ/mol; 3.1 kcal/mol), determined by urea denaturation, was identical for both the native and ligand-bound Moniezia LBP. CD spectra showed that the Moniezia protein contained 36% alpha-helix and that the secondary structure underwent only minor changes on ligand binding. Moniezia LBP binds a range of anthelmintics, with KD values again in the range 0.66-7.3 microM. It is possible that, in helminths, binding proteins may play a role in determining the specificity and site of action of anthelmintics.

Amino Acid Sequence↗
PubMed1986

[Description of Hymenolepis cerberensis n. sp. (Cestoda: Hymenolepididae) and first general considerations on the fauna of cestode parasites of the pygmy shrew Suncus etruscus (Savi, 1822) (Insectivora: Soricidae)].

Description and differentiation of the adult stage of Hymenolepis cerberensis n. sp. (Cestoda: Hymenolepididae), an intestinal parasite of the Pygmy white-toothed shrew, Suncus etruscus (Savi, 1822) (Insectivora: Soricidae: Crocidurinae) in the region of Banyuls-sur-Mer and Cerbère (Oriental Pyrenees, France). The new species is characterized by the size of the gravid specimens and by the presence of 18-21 rostellar hooks of 18.5-20 micron and of filaments around the embryophore. The general composition of the fauna of Cyclophyllidea parasitizing S. etruscus is analysed. There are three less specialised Hymenolepis species with a scolex of the same type and one Pseudhymenolepis species, with the absence of unarmed species lacking a rostrum. The oioxenous character of the Cestodes parasitizing Suncus species sustains the validity of the genus Suncus. The resemblance of the Cestodefaunas suggests a narrow phyletic relationship between the genera Suncus and Crocidura.

Animals↗
PubMed1991

Pseudhymenolepis turkestanica sp. n. (Cestoda: Hymenolepididae), a new cestode from shrews.

An illustrated description of the Pseudhymenolepis turkestanica sp. n., a new cestode from piebald shrew (Diplomesodon pulchellum) from Middle Asia is given. P. turkestanica differs from the most similar species P. papillosa Hunkeler, 1970 by the measures of the scolex and rostellum, the number of rostellar hooks and the size of embryonic hooks. P. turkestanica is considered as a specific parasite of D. pulchellum.

Animals↗
PubMed1985

Biochemical differentiation in bile duct cestodes and their marsupial hosts.

Isozyme electrophoresis was used to assess possible cospeciation of parasites (cestodes of the Progamotaenia festiva complex) and their hosts (Australian diprotodont marsupials) and to compare the extent of interspecific genetic diversity of the parasites and their hosts. On the basis of morphology, there are three species in the complex, although electrophoresis revealed 14 distinct genetic types, most of which were host specific, although there were three cases of apparent host switching. The evolutionary relationships among the parasites were only partially concordant with those among the hosts. Moreover, the extent of electrophoretic diversity among the parasites was much higher than that among hosts.

Animals↗
PubMed1965

Cestode in North Dakota: echinococcus in field mice.

Field mice (Microtus pennsylvanicus and Peromyscus maniculatus) are naturally infected with Echinococcus multilocularis. Thus, the sylvatic cycle (fox to field mice to fox) has been established in North Dakota. This cestode is expected to extend its range to other agricultural regions of the continental United States where similar conditions favorable for the completion of its life cycle exist.

Animals↗
PubMed1991

The effect of L-glutamate and related agents on adenylate cyclase in the cestode Hymenolepis diminuta.

The effect of the putative amino acid transmitter, L-glutamate, on adenylate cyclase in crude membrane preparations of the rat tapeworm Hymenolepis diminuta was investigated to determine if glutamate effects the generation of the second messenger cAMP. Addition of glutamate at 10(-3) and 5.5 x 10(-9) M resulted in significant elevations in basal activity of adenylate cyclase, while concentrations in the 10(-5)-10(-7) M range caused significant depressions below basal activity. Assays with glutamate agonists and other acidic compounds showed glutamate to be the only amino acid, dicarboxylic acid, or acidic compound capable of this pattern of stimulation and inhibition. While the response of adenylate cyclase to glutamate agonists suggested that an N-methyl-D-aspartic acid (NMDA) type receptor may be present, glutamate agents acting as NMDA antagonists in vertebrate systems were agonists. Metabolic end products of glycolysis stimulated adenylate cyclase, suggesting that these, along with metabolic glutamate may regulate glycolytic enzymes. Only 10(-3) M L-glutamate significantly stimulated adenylate cyclase activity in tissue slices, and this response was restricted to those slices rich in nervous tissues. L-Glutamate eliminated the 5-hydroxytryptamine (5-HT) stimulated adenylate cyclase response suggesting that glutamate can modulate the 5-HT stimulated elevations in adenylate cyclase activity. The data support the hypothesis that L-glutamate is a neurotransmitter-modulator in the cestode.

1-Methyl-3-isobutylxanthine↗