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At least 19 recordsLinked to original sources
PubMed2006

Schistocephalus cotti n. sp. (Cestoda: Pseudophyllidea) plerocercoids from bullheads Cottus gobio L. in an Arctic river in Finland, with a key to the plerocercoids of the Palaearctic species of the genus.

We compared plerocercoids of Schistocephalus Creplin, 1829 from Cottus gobio (n = 57) and Gasterosteus aculeatus f. semiarmatus (n = 45) from the River Utsjoki, Finland, taken only from single worm infections. Segment numbers in the two populations were distinct (G. aculeatus range 55-107, average 74 (SE 1.66), median 73; C. gobio range 122-189, average 146 (SE 1.78); median 144). The mean difference between populations, 71.47, t = 28.76 with 100 degrees of freedom, two-tailed p value <0.001, was considered extremely significant. Amplification of microsatellite loci that were originally designed for Schistocephalus from G. aculeatus was positive for all larvae from G. aculeatus (n = 20), whereas in no plerocercoids from C. gobio (n = 20) were any of the six microsatellites amplified, indicating that plerocercoids from G. aculeatus and C. gobio were two distinct genetic populations of Schistocephalus. The material from C. gobio is described as S. cotti n. sp. Plerocercoids of the Palaearctic species of Schistocephalus are identified as follows: S. nemachili Dubinina, 1959 with 228-235 or more segments, specific to Barbatula spp. (Balitoridae); S. pungitii Dubinina, 1959 with 62-92 (usually 70-80) segments, specific to Pungitius pungitius; S. solidus (Müller, 1776) in two forms, one in G. aculeatus f. leiurus and f. semiarmatus, with 48-100 (usually 65-75) segments, and the other in G. aculeatus f. trachurus, with 99-138 (usually 112-122) segments; and S. cotti n. sp. with 103-189 (usually 130-159) segments, probably specific to cottids. Nearctic Schistocephalus were not considered owing to the uncertain status of some North American records. Some other species of Schistocephalus of highly doubtful status were briefly noted. Cross-infection experiments and molecular studies are recommended to further elucidate the interrelationships between the various species of Schistocephalus.

Animals↗
PubMed1992

Infectivity of plerocercoids of Schistocephalus solidus (Cestoda: Ligulidae) and fecundity of the adults in an experimental definitive host, Gallus gallus.

Aspects of the infectivity of the plerocercoid stage and the fecundity of the adult stage of Schistocephalus solidus were examined using the chicken, Gallus gallus, as an experimental host. To investigate size-related infectivity of the plerocercoid stage to a definitive host, a range of plerocercoids (166) were weighed, and each was fed to an individual male chicken. Only a very small percentage of plerocercoids weighing less than 50 mg established compared with in excess of 50% in all other weight classes. To examine the factors affecting the quantity of eggs produced by the adult stage, 15 similar-sized plerocercoids (160-218 mg) were fed to chickens. The majority of plerocercoids administered established as adults and survived until the experiment was terminated on day 7 postinfection (PI). Fecal egg counts indicated that all established worms commenced egg production on day 2 PI with peak output on day 2 or 3 PI. By day 7 PI, egg production in the surviving worms had declined, but it was still evident. The final weight of the adult and the average egg output per worm were unrelated to the initial weight of the infecting plerocercoid. However, the average egg output was predicted by the final adult dry weight and to a lesser extent by the proportion of weight lost in the transition from plerocercoid to adult, but not by the absolute weight loss.

Analysis of Variance↗
PubMed2004

Stage-specific expression genes of the Spirometra erinaceieuropaei plerocercoid screened by mRNA differential display technique.

BACKGROUND: The stage-specific expression of genes is one of the most characteristics of parasites. It has been found that a lot of genes of Spriometra erinaceieuropaei are specifically expressed in pleroceroid in large amount, but not expressed when the plerocercoid development into adult worm. The study is to screen other stage-specific ecpression genes of plerocercoid of Spirtmetra erinceieuropaei. METHODS: RNA was separately extracted by acid guanidinium thiocyanate-phenol-chloroform from plerocercoids and adult worms of Spirometra erinaceieuropaei, DNA contaminated in the RNA was digested by RNase-free DNase. After the RNA was reverse transcripted to cDNA using T12MA, T12MC, T12MG and T12MT anchor-primers, PCR was done using the same T12MN and one random primer with alpha 35S-dATP in the system. The PCR products were fractionated on an 8% denatured polyacrylamide gel. Differential bands of the plerocercoid found in the gel were cut out, amplified by PCR and sequenced. Northern hybridization was used to identify the stage-specific expression genes. RESULTS: Eleven differential bands were selected from the gel and classified into 3 kinds of gene fragments by hybridization, after they were amplified by PCR. Fragments 1 (238 bp) and 2 (383 bp), were confirmed by Northern hybridization, as being expressed in the plerocercoid. However, fragment 3 (433 bp), was expressed in both the plerocercoid and the adult worm. Data from the 3 gene fragments underwent homological analysis in GenBank. The sequence which was homologous with fragments 1 and 2 was not found, but fragment 3 had high homology with many kinds of 28S rRNA. CONCLUSIONS: The gene expressions of plerocercoids are different from adult worms because they live in different hosts. Two types of different gene fragments from the plerocercoid were found by mRNA differential display technique.

Animals↗
PubMed1986

Lipid metabolism in golden hamsters infected with plerocercoids of Spirometra erinacei (Cestoda: Pseudophyllidea).

Golden hamsters infected with Spirometra erinacei plerocercoids develop a hypertriglyceridaemia characterized by an increase in very low-density lipoprotein. Acyl-CoA synthetase activity, the rate of fatty acid synthesis in the liver and triglyceride production studies showed that the activation and synthesis of fatty acid and production of triglyceride in plerocercoid-infected hamsters were not significantly different from the controls. Lipase activity in post-heparin plasma was found to be suppressed in plerocercoid-infected golden hamsters. The presence of plerocercoids also resulted in a significant reduction in serum thyroxine, but the hypertriglyceridaemia associated with plerocercoid infection was not reversed by injecting the infected hamsters with 2 micrograms/day doses of L-thyroxine. The levels of serum immunoreactive insulin in plerocercoid-infected hamsters were not significantly different from the controls. We conclude that the hypertriglyceridaemia, associated with plerocercoid infection in hamsters, results predominantly from a suppression of triglyceride degradation, and that the suppression of lipase activity is probably not the result of hypothyroidism or the lack of insulin, but the result of secretion of growth hormone-like substances.

Animals↗
PubMed2000

Effect of temperature on fatty acid composition in each lipid fraction of Spirometra erinaceieuropaei plerocercoids.

The effects of temperature and host fatty acids on the fatty acid contents of Spirometra erinaceieuropaei plerocercoids were investigated to clarify their role in sparganosis. After 24 hr incubation at 18 C in host snake serum, omega6 series fatty acids, especially arachidonic acid in the phospholipid fraction of the plerocercoids, increased compared with those of plerocercoids incubated at 37 C. The changes in the ratio of polyunsaturated to saturated fatty acids in the phospholipid fraction of plerocercoids incubated in physiological saline for 6 hr at 10 C were almost the same as the changes at 37 C. The ratio of polyunsaturated to saturated fatty acids of the triglyceride fraction showed almost opposite change versus the phospholipid fraction. The percentage of arachidonic acid in the phospholipid fraction of plerocercoids increased during the first 3 hr of incubation and then decreased, regardless of temperature. At 37 C, the percentage of arachidonic acid in the free fatty acid fraction fell for the first 3 hr of incubation and was significantly elevated at the end of the 6-hr incubation. At 10 C, however, arachidonic acid in the free fatty acid fraction decreased for the first hour of incubation, increased at 3 hr of incubation, then decreased again. These results suggest that fatty acids of the plerocercoids are frequently exchanged between fractions. Plerocercoids can mobilize arachidonic acid to the free fatty acid fraction more quickly at lower temperature than at higher temperature. They may utilize mobilized arachidonic acid early in the infection stage to produce prostaglandins. Alternatively, they can incorporate arachidonic acid into the phospholipid fraction again when arachidonic acid is readily available in the environment.

Animals↗
PubMed2002

[Screening of stage-specific expression genes of Spirometra erinacei-europaei plerocercoid by mRNA differential display technique].

OBJECTIVE: To screen stage-specific expression genes of plerocercoid of Spirometra erinacei-europaei. METHODS: RNA was extracted by the acid guanidinium thiocyanate-phenol-chloroform from plerocercoid and adult worm of Spirometra erinacei-europaei. Contaminated DNA in the RNA was digested by RNase-free DNase. cDNA was synthesized by using T12MA, T12MC, T12MG and T12MT primers, and PCR was then done using the same T12MN and one random primers. The PCR products were fractionated on 8% denatured polyacrylamide gel, differential bands of plerocercoid found in the gel were cut out, amplified by PCR and sequenced after the gel was dried out and autoradiographed. Northern hybridization was conducted to identify the stage-specific expression genes. RESULTS: Eleven differential bands were selected from the gel and classified into 3 kinds of gene fragments by hybridization after they were amplified by PCR. The fragments 1 and 2 were confirmed to express specifically in plerocercoid by Northern hybridization, but the fragment 3 was expressed in both plerocercoid and adult worm. When the 3 gene fragments were homologically analyzed in GenBank, the sequence which was homologous with the fragments 1 and 2 was not found, but the fragment 3 had high homology with many kinds of 28S rRNA. CONCLUSION: The gene expression of plerocercoid was different from that of adult worm probably because they live in different hosts. Two kinds of different gene fragments in plerocercoid were identified by mRNA differential display technique.

Amino Acid Sequence↗
PubMed1982

The lipogenic effect of the growth factor produced by plerocercoids of the tapeworm, Spirometra mansonoides, is not the result of hypothyroidism.

Plerocercoid larvae of the tapeworm, Spirometra mansonoides produce a growth hormone-like factor that stimulates body growth of a variety of normal and hormone-deficient animals. Plerocercoid infection (15 per hamster) stimulated an increase in body weight, and markedly suppressed pituitary weight and growth hormone (GH) concentrations of serum and pituitaries of Syrian hamsters. The suppression of serum GH persisted for at least 4 mo after the initiation of infection. The presence of plerocercoids also resulted in a significant reduction (30-50%) in serum thyroxine (T4). The pronounced lipogenic effect associated with plerocercoid infection was not reversed by injection of the infected hamsters with high (10 or 20 micrograms/day) or low (1 or 2 micrograms/day) doses of L-thyroxine. These results suggest that the plerocercoid growth factor may function in a manner similar to high levels of endogenous GH by activating the feedback system that inhibits pituitary secretion of both GH and TSH. Whereas hypothyroidism may be associated with hyperlipidemia the resultant hypothyroid state induced by plerocercoid infection does not explain the hypertriglyceridemia and hypercholesterolemia which were a consistent observation in plerocercoid-infected hamsters.

Animals↗
PubMed1988

Effect of infection with Spirometra erinacei plerocercoid on thyroid hormone in mice.

Young, male ICR mice were given tap water or distilled water containing 200 mg/l propylthiouracil (PTU) and were then infected with 10 plerocercoids of Spirometra erinacei to investigate the effect of plerocercoid infection on thyroid hormone in their hosts. Plerocercoid infection stimulated growth in PTU-induced hypothyroid mice as if they had never received PTU treatment: there were increases in weight in the liver, skeletal muscle, and spleen, as well as enhancement of the head and body length, in spite of a greater decrease in serum T4 levels than was observed in PTU-treated controls. Furthermore, the intact mice infected with plerocercoids showed a decrease in serum T4 levels as well as in the concentration of T4-binding globulin. These observations suggest that the growth stimulation and the decrease in concentrations of serum T4 and T4-binding globulin associated with plerocercoid infection in mice probably resulted from secretion of a growth hormone-like substance produced by plerocercoids of S. erinacei.

Animals↗
PubMed1997

Development of the plerocercoid I of Ophiotaenia europaea in reptiles.

The existence of a two-host life-cycle in ophiotaeniid proteocephalideans was tested experimentally using Ophiotaenia europaea as a model. Three species of reptiles, Natrix natrix, Natrix tessellata and Lacerta viridis, were fed with experimentally infected copepods containing a large number of infective plerocercoids I. A few plerocercoids, most of which were dead, corresponding morphologically to the plerocercoid II developmental stage of O. europaea, were found encysted in the intestinal wall of N. natrix (8 days p.i.), N. tessellata (5 and 150 days p.i.) and L. viridis (40 days p.i.), while no plerocercoids or adult worms were recovered from their intestines. The results indicate that the infective plerocercoid I of O. europaea cannot undergo further development when ingested directly by the final host (a reptile), and that environmental temperature stimuli cannot initiate a reverse plerocercoid migration to the gut followed by strobilization.

Animals↗
PubMed1983

Effects of Spirometra erinacei plerocercoids on the growth of Snell dwarf mice.

Snell normal and dwarf mice were infected with Spirometra erinacei plerocercoids collected in Japan, to investigate the relationship between the growth-promoting effects of plerocercoids and the growth hormone releasing factor and the somatostatin--growth hormone--somatomedin axis in the host. Infection with plerocercoids caused increases in body weight and weights of muscle, liver, spleen and heart in the normal male mice, and increases in the head--body length, body weight and weights of muscle, liver, spleen, kidney and heart in the normal female mice, but did not increase the weight of the fat pad. Infection with plerocercoids caused increases in body weights and weights of muscle, liver and spleen in the male dwarf mice, and increases in the head--body length, body weight and weights of muscle, liver, spleen and kidney in the female dwarf mice. These observations suggest that plerocercoids promote the growth of dwarf mice as well as normal mice. As the dwarfism of Snell mice is due to a defective anterior pituitary gland, it seems that plerocercoids do not stimulate secretion of growth hormone from the pituitary. Accordingly, it seems to be more probable that the larvae secrete a growth hormone-like substance.

Animals↗
PubMed2002

Chemical structures and immunolocalization of glycosphingolipids isolated from Diphyllobothrium hottai adult worms and plerocercoids.

Glycosphingolipids (GSLs) were purified from adults and plerocercoids of the tapeworm Diphyllobothrium hottai, and their chemical structures were determined. Total lipid fractions prepared from chloroform/methanol extracts of whole tissues were fractionated successively on ion-exchange chromatography, silicic acid column chromatography, and preparative TLC. The purified GSLs were characterized by methylation analysis, TLC-immunostaining, liquid secondary ion MS, MALDI-TOF MS, and 1H-NMR. Ten GSLs were isolated from adult worms and four from plerocercoids, comprising mono-, di-, tri-, tetra-, and pentasaccharides. The GSL Gal beta 1-4(Fuc alpha 1-3)Glc beta 1-3Gal beta 1-Cer was found in adult worms but not in plerocercoids, whereas Ga lbeta 1-4 (Fuc alpha 1-3)Glc beta 1-3(Gal beta 1-6)Gal beta 1-Cer was found in both adult worms and plerocercoids. We previously found a similar series of GSLs in plerocercoids of the cestode Spirometra erinaceieuropaei, and termed them 'spirometosides'[Kawakami, Y. et al. (1996) Eur J. Biochem. 239, 905-911]. The core structure of spirometosides, Gal beta 1-4Glc beta 1-3 Gal beta 1-Cer, may have taxonomic significance, being characteristic of pseudophyllidean tapeworms. In the present study, GSL compositions were significantly different between adults and plerocercoids, and growth-dependent changes in composition were documented. We found a novel dihexosylceramide, Glc beta 1-3Gal beta 1-Cer, which is a possible precursor for spirometosides. Immunohistochemical examination showed that spirometoside GSLs are highly enriched in the inner surface of bothria, the major point of contact between the adult worm and the host's intestine. Our findings indicate that spirometosides are involved in host-parasite interaction.

Animals↗
PubMed1977

A lipogenic effect in intact male hamsters infected with plerocercoids of the tapeworm, Spirometra mansonoides.

Plerocercoids of the tapeworm, Spirometra mansonoides, produce a potent growth stimulating substance which is active in several species of mammals. While most of the actions of the plerocercoid growth factor (PGF) are similar to those of growth hormone (GH), lipid metabolism is one area where their actions are not alike. This report demonstrates that plerocercoid infection not only stimulates growth of intact male hamsters but is lipogenic as well. The lipogenic effects of plerocercoid infection were demonstrated by increases in epididymal fat pad weights, serum triglycerides, cholesterol, and total lipid. The livers of the plerocercoid-infected hamsters also had more cholesterol and more lipid phosphorus than controls. Incorporation studies using [2-14C]acetate showed that infected hamsters incorporated significantly higher levels of the radionuclide in their livers and serum after 1 hr than the controls. The lipogenic effect of plerocercoid infection is distinctly unlike the reported lipolytic action of GH and the lack of any stimulation of [2-14C]acetate incorporation into the epididymal fat pads is unlike the reported acute actions of insulin as well.

Acetates↗
PubMed1986

Evidence of the growth factor in mouse serum infected with Spirometra erinacei plerocercoids.

To investigate the action of the growth factor secreted by Spirometra erinacei plerocercoids, various organ weights, body weight and head-body length were measured in Snell normal and dwarf mice after injection with the serum from mice and rats. Serum from mice infected with the plerocercoids caused significant increases in the weights of the liver and spleen, in the same manner as mice infected with the plerocercoids. However, serum from rats infected with plerocercoids did not cause significant changes in these parameters. The growth factor in the serum of mice infected with plerocercoids was stable at -20 degrees C for at least 6 months and easily passed through the peritoneum.

Animals↗
PubMed1992

A double surface membrane in plerocercoids of Ligula intestinalis (Cestoda: Pseudophyllidea).

The tegument of Ligula intestinalis plerocercoids is delimited by a membrane complex that in electron microscopy appears heptalaminate. We suggest that the plerocercoids are covered by two closely apposed lipid bilayers. Double membranes, which are well known in schistosomes, are thus not a unique feature of blood parasitic Digenea but could be documented for the first time in a cestode species that lives in the peritoneal cavity of its host. The surface-membrane complex of plerocercoids was lost for the most part after conventional preparation for electron microscopy but could be completely retained by improved fixation using osmium tetroxide plus potassium ferrocyanide. Furthermore, one type of vesicle in the tegumental syncytium of plerocercoids has been found to be enclosed by at least two membranes, which might indicate that these vesicles contribute to the renewal of the surface-membrane complex. Adult Ligula intestinalis removed from the gut of the final host Anas platyrhnychos or obtained by in vitro transformation exhibited a single surface membrane and lacked double membrane vesicles. The elongate electron-dense caps of the microtriches of plerocercoids were replaced by short caps in the course of worm maturation. Thus, the tegumental surface of this parasite is fundamentally altered following the change in its environment from the peritoneal cavity of the intermediate host to the intestine of the final host.

Animals↗
PubMed1995

The fatty acids of each lipid fraction and their use in providing energy source of the plerocercoid of Spirometra erinacei.

The fatty acid concentration of each lipid fraction of plerocercoids of Spirometra erinacei and the host snake serum was investigated. The major fatty acids of phospholipid of the plerocercoids were C18:1, C18:0 and C16:0, and those of the host snake serum were C16:0, C18:1 and C18:0, in order of amount in both cases. The changes of the fatty acid composition of phospholipid of the plerocercoids when they were incubated in physiological saline at 18 degrees C and at 37 degrees C for 24 h were investigated in both cases. Polyunsaturated fatty acids increased at 18 degrees C, and saturated fatty acids increased at 37 degrees C. Michaelis constants (Km) of beta-hydroxyacyl-CoA dehydrogenase (HAD), NADH: ubiquinone oxidoreductase (complex I) (NADH: ferricyanide reaction) and complex I (NADH: ubiquinone reaction) for NADH were 20.6, 50 and 13.3 microM, respectively. The ATP production in mitochondria of the plerocercoids was accelerated by adding ADP and inhibited by adding such electron transport system inhibitors as rotenone, antimycin A and sodium cyanide. These results suggested that the fatty acids in the plerocercoids played an important role in regulating the fluidity of membrane by changing the composition in membrane lipid corresponding with the change of temperature circumstance. The NADH reduced by HAD might be accepted by the complex I in the electron transport system, and thus the parasites were capable of ATP production in a classical pathway of the oxidative phosphorylation system.

Adenosine Triphosphate↗
PubMed2005

Tetraphyllidean plerocercoids from Western Mediterranean cetaceans and other marine mammals around the world: a comprehensive morphological analysis.

Tetraphyllidean plerocercoids have occasionally been reported in marine mammals, but they have rarely been described in detail, and the ecological significance of these infections is unclear. We described plerocercoids collected from the mucosa of the terminal colon and rectum, the anal crypts, and the hepatopancreatic ducts of 7 striped dolphins Stenella coeruleoalba, 1 Cuvier's beaked whale Ziphius cavirostris, and 3 Risso's dolphins Grampus griseus from the Spanish Mediterranean. We also examined undescribed plerocercoids from 3 cetacean species from the Atlantic and the Pacific. All plerocercoids had a lanceolate body, and a scolex with an apical sucker and 4 sessile monolocular bothridia. The bothridia had free posterior edges and an accessory sucker at their anterior end. Under light microscopy, the bothridia of some Mediterranean specimens looked bilocular without accessory suckers, but a true accessory sucker was observed in histological sections. A principal component analysis revealed 2 stable clusters of specimens along the first principal component regardless of host species. These "large" and "small" morphotypes are thought to represent early migratory stages of Phyllobothrium delphini and Monorygma grimaldii. The similarity in scolex morphology, the observation of plerocercoids buried in intestinal regions close to the sites where M. grimaldii and P. delphini occur, and the coexistence of all larval forms in the same individual hosts would support this hypothesis. Future molecular analysis may confirm it.

Anal Canal↗
PubMed1993

Purification and partial characterization of cysteine proteinase from Spirometra mansoni plerocercoids.

Spirometra mansoni plerocercoids were dissected from the tissues of naturally infected snakes (Natrix trigrialateralia). Fresh plerocercoids were incubated in medium, and excretory-secretory products (E-S) were collected. In addition, soluble proteins from lyophilized plerocercoids (10 mg/ml) were extracted in 0.1 M sodium acetate. Proteinase activity was assayed with a synthetic fluorescent substrate, carbobenzoxy-phenylalanyl-arginyl-7-amino-4-trifluoromethylcoumarin. Proteinase was isolated from plerocercoid extract or E-S by diethylaminoethyl trisacryl M ion-exchange chromatography and thiolpropyl-Sepharose affinity chromatography. These separations resulted in a 12.2- (extract) and 15.6-fold (E-S) purification of proteinase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified materials revealed a 28-kDa band, consistent with the apparent native molecular weight (gel filtration chromatography) of approximately 35 kDa. Proteinases purified from whole extracts and E-S were compared for various biochemical characteristics; inhibitor profiles indicated that activities from both sources are cysteine proteinases, they exhibited identical pH curves with optima at pH 5.5 and a 50% activity range at pH 4.7-8.0, they cleaved collagen chains to 3 identical products, and they showed only minor activity toward hemoglobin. Further, the proteinase purified from plerocercoids was utilized in immunoblots with sera from sparganosis patients. Antibody (IgG) from the infected patients, but not uninfected controls, recognized the cysteine proteinase, suggesting that this antigen may be useful in the serodiagnosis of Spirometra mansoni infection.

Animals↗
PubMed1995

Length-weight relationship of Ligula intestinalis plerocercoids in adult silver bream and discussion on estimation of the parasite age.

The paper comprises an evaluation of Ligula intestinalis infection in adult silver bream (Blicca bjoerkna), from the Nové Mlýny Reservoirs (Czech Republic), from 1991 to 1993. The prevalence (mean 4.39%) and intensity (mean 1.39 spec.) of infection were very low, ranging from 1.48% (1.11 spec.) in April-May to 11.52% (1.36 spec.) in November-December. The length-weight relationship of single infection plerocercoids was characterized by the regression and correlation coefficients of linear and exponential regressions. The lowest weight and mean lengths of plerocercoids were found in April-May. According to the length and weight of plerocercoids in our collection those specimens were preliminary separated into 0+ to 5+ age classes. It is supposed that the longevity of the longest specimens of L. intestinalis plerocercoids attain the same age as their intermediate host (silver bream). The longest plerocercoid attained the body length of 1,006 mm and the weight of 32.0 g.

Age Factors↗