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At least 217 records · Page 12Linked to original sources
PubMed1983

Characterization of cobalamin receptor sites in brush-border plasma membranes of the tapeworm Spirometra mansonoides.

The interaction of receptor sites in microtriches (brush-border) membranes isolated from the sparganum (larva) of the cestode (tapeworm) Spirometra mansonoides with [57Co]cyanocobalamin (CN-[57Co]Cbl) has been characterized on the basis of the following criteria: time dependence, reversibility, high-affinity binding, finite binding capacity, and ligand specificity. The association of CN-[57Co]Cbl to isolated microtriches membranes at 22 degrees C reached equilibrium in approximately 90 min. The initial rate of association follows second order kinetics with an association rate constant (ka) of 1.1 X 10(6) M-1 S-1. In the presence of an excess of unlabeled CN-Cbl, the receptor CN-[57Co]Cbl complex dissociated according to first order kinetics with a dissociation constant (kd) of 4.4 X 10(-4) S-1. An equilibrium dissociation constant (KD) of 0.4 nM was calculated on the basis of rate constants (KD = kd/ka). Scatchard analysis of equilibrium-binding data revealed a single class of high affinity binding sites with a KD of 0.3 nM and a maximum binding capacity for CN-Cbl of 221 fmol/mg of membrane protein. The stereo-specificity of CN-Cbl binding to receptor sites in isolated microtriches membranes was determined using various Cbl analogs. Receptor-site binding affinity was lowered by the following modifications: deamination of the b-, d-, and e-propionamide side chains to the corresponding monocarboxylate derivatives; modification of the B pyrrole ring to lactam or lactone; substitution of the benzimidazole moiety by a purine; modification of the benzimidazole; or deletion of the entire nucleotide moiety. On the basis of the action of trypsin and pronase, this CN-Cbl receptor may contain a relatively exposed membrane protein. The physiological role of this CN-Cbl receptor in the binding, internalization, and metabolism of Cbl is discussed in relation to cestodes and their mammalian hosts.

Animals↗
PubMed1983

[Efficacy of paromomycin sulfate against human cestodiasis and its pharmacological action on tapeworm in vitro].

Recently, it has been reported that paromomycin sulfate has marked anthelmintic efficacy against tapeworm infections in man. In the present study this drug was used in the treatment of 14 cases of diphyllobothriasis latum and 1 case of taeniasis saginata. Also, the actions of paromomycin sulfate on Diphyllobothrium ditremum and D. erinacei were examined pharmacologically using Magnus apparatus and biochemical methods. The results obtained were as follows. For the treatment, a total of 50 mg/kg of paromomycin sulfate divided into 2 doses was given orally at intervals of 30 minutes. Two hours after medication, 20 g of magnesium sulfate dissolved in 200--300 ml of water was given as purgative. One or 2 worms were found in the stools of 11 cases with D. latum and 1 case with T. saginata within 24 hours after medication, but scolex was found in only 2 of them. All cases were negative for the eggs or segments in stool examinations at 1 and 3 months after treatment. Except 1 case complained mild and transient vomiting no side effects were noticed. All cases showed no abnormality in blood examination, liver function test and urinalysis. Both of the proglottids of D. ditremum and D. erinacei showed muscle relaxation in Tyrode solution containing 10(-4) g/ml of paromomycin sulfate. In D. ditremum the recovery of muscle tonus was observed within 10--15 minutes after affection of this drug, while the persistence of muscle relaxation was seen in D. erinacei. The activity of phosphoglucose isomerase was slightly inhibited by 10(-3) M paromomycin sulfate while those of hexokinase, phosphofructokinase and glucose-6-phosphate dehydrogenase were not inhibited. In phosphoenolpyruvate-succinate pathway, the activity of fumarate reductase was slightly inhibited 10(-3) M paromomycin sulfate while those of phosphoenolpyruvate carboxykinase and malate dehydrogenase were not inhibited.

Adolescent↗
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↗
PubMed1981

Factors regulating tapeworm populations: estimations of the duration of acquired immunity by sheep to Taenia hydatigena.

Lambs reared from birth in a 'tapeworm-free' unit were immunised at three months old by a parenteral injection of the embryos of Taenia hydatigena. Subsequently, they were grazed with unimmunised control animals on an egg-free pasture. At one, three, six, nine, 12 or 15 months after immunisation, groups of the treated and control animals were grazed for eight weeks on an experimental egg-contaminated pasture. Strong immunity was shown up to three months after immunisation by the presence of only a few pinhead lesions in the lamb's liver. At six and nine months after immunisation, the lesions were similar in size to those in the control animals. While a few organisms reached the abdominal cavity in animals grazed six and nine months after immunisation, no viable cysts were found until 12 months. Seven-year-old sheep, which had been naturally infected with T hydatigena at an early age but had rarely ingested eggs since, were also grazed on the egg-contaminated pasture. Populations of original and superimposed metacestodes were observed in the abdominal cavity of some of them. The first experiment investigated the duration of immunity to the embryo, reorganising larva and metacestode in the absence of further egg infections. The second experiment confirmed that original and superimposed cyst populations can coexist.

Animals↗
PubMed1981

Photoreactivating enzyme activity in the rat tapeworm, Hymenolepis diminuta.

There has been considerable speculation about the occurrence of photoreactivating enzyme in different organisms and about its biological purpose. We have developed a simple, sensitive assay for estimating pyrimidine dimers in DNA which is useful in making a rapid survey for the presence of the enzyme. Using this method, we have found photoreactivating enzyme activity in the tissues of the rat tapeworm Hymenolepis diminuta. This parasite spends the majority of its life span in the bodies of its definitive or intermediate hosts, but a period is spent externally. We suggest that photoreactivating enzyme may be important in preserving the integrity of embryonic DNA during this free-living stage.

Animals↗
PubMed1993

[Localization and activity of several enzymes in tissues of Bothriocephalus acheilognathi and Khawia sinensis tapeworms parasitizing carp].

In this study, an attempt has been made to compare the most common species of tapeworms in carp: non-segmentary Khawia sinensis and segmentary Bothriocephalus acheilognathi on the basis of histoenzymatic examination of 8 enzymes, i.e. alkaline phosphatase, acid phosphatase, adenosine triphosphatase, nonspecific esterase alfa, succinic dehydrogenase, lactate dehydrogenase, leucine aminopeptidase and gamma-glutamylo transferase.

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↗
PubMed1996

[Localization and activity of some hydrolases in larvae of tapeworms Neogryporhynchus cheilancristrotus and Triaenophorus nodulosus parasitizing fish].

In the study, an attempt was undertaken to compare the most common species of tapeworms' larvae in fish: N. cheilancristrotus and T. nodulosus on the basis of histoenzymatic examination of 3 enzymes: alkaline phosphatase (AP), acid phosphatase (APh) and nonspecific esterase (EN-alpha). The high activity of AP and APh in the cuticle and subcuticular cells, and the lack of EN-alpha activity in these structures was stated. Besides, an intensive AP and EN-alpha activity took place in the N. cheilancristrotus scolex, compared to the appropriate T. nodulosus segment in which the reaction was slight.

Acid Phosphatase↗
PubMed1976

Factors regulating tapeworm populations: estimations of the build-up and dispersion patterns of eggs after the introduction of dogs infected with Taenia hydatigena.

The build-up of the eggs of Taenia hydatigena was measured on a pasture following the introduction of infected dogs. Susceptible lambs grazed on the pasture beforehand showed that only small numbers of randomly dispersed infective eggs were present. Two dogs each with four patent T hydatigena were chained to kennels placed in the middle of the pasture. The build-up of eggs was determined by grazing further tapeworm-free lambs there for 10-day periods. High cyst counts were obtained in some of these lambs grazed within 10 days of the introduction of the infected dogs. The mean cyst counts remained at a similar level during the 85-day investigation. This indicated that at least part of the pasture became virtually saturated with eggs shortly after the dogs were introduced and remained so while the dogs were there. Some animal management practices that favour this 'epidemic' pattern and lead to a 'cysticercosis storm' are discussed.

Animals↗
PubMed1976

Factors regulating tapeworm populations: the changing opportunities of lambs for ingesting the eggs of Taenia hydatigena.

Some intrinsic factors that may modify the transmission of cysticercosis caused by Taenia hydatigena in lambs have been assessed and the age at which the infective pattern should no longer be modified by the grazing-learning process and by colostrum-derived antibody, estimated. Lambs of 0-1, 2-3, 5-6, 8-9, 11-12 weeks of age, were placed for one week on a pasture experimentally contaminated with eggs of T hydatigena. The lambs were allowed to suck their mothers from birth. About half the lambs up to three weeks of age were free from larval tapeworms at autopsy; the rest had only a small number of cysts. Some of the lambs grazed on the pasture at or after five weeks of age, became heavily infected. The light infections in the very young lambs could have resulted from either a limited contact with eggs or from passively transferred antibody or, more likely, from a combination of these factors. The high cyst counts observed in some of the older lambs were consistent with the ingestion of eggs in clusters. The rise in the total cyst counts was concomitant with increasing pasture intake. The higher survival rates for the cysts found in the older rather than the younger animals were compatible with the waning before five weeks of age of colostrum-derived antibody.

Age Factors↗
PubMed1998

Evidence that the factor used by the tapeworm, Hymenolepis diminuta, to direct the foraging of its intermediate host, Tribolium confusum, is a volatile attractant.

We have previously demonstrated that flour beetles, Tribolium confusum, are more attracted to the feces from rats with patent Hymenolepis diminuta infections than to feces from uninfected rats. The objective of this study was to determine if this effect is due to a volatile attractant. Volatile substances emitted by feces from H. diminuta-infected rats or from uninfected controls were collected by aspirating fresh rat feces, while trapping the volatiles on Porapak Q (a solid adsorbant). The volatiles were eluted from the Porapak Q with diethyl ether, and the relative attractancy of the volatiles to prestarved beetles was assessed by bioassay. More beetles were attracted to volatiles of feces from infected rats than to volatiles of feces from uninfected controls (P< or =0.0001). The magnitude of the response varied with the time in the bioassay test arena and also the concentration of the volatiles (P< or =0.0232). When the volatiles we re concentrated by aspirating more boli over a longer period of time, the beetles responded more quickly and in greater numbers to the volatiles of feces from infected rats. The experiments presented here provide the first indication that a tapeworm (H. diminuta) can enhance its chances of transmission by directing the foraging of its intermediate host (T. confusum) through the use of attractive, volatile material released from the feces of its definitive host.

Animals↗