Effects of parasite strain and intermediate host species on carbohydrate intermediary metabolism in the rat tapeworm, Hymenolepis diminuta

1984 ◽  
Vol 62 (3) ◽  
pp. 355-361 ◽  
Author(s):  
D. F. Mettrick ◽  
M. S. Rahman
Keyword(s):  
Intermediate Host ◽  
Carbohydrate Metabolism ◽  
Parasite Species ◽  
Adenine Nucleotide ◽  
Hymenolepis Diminuta ◽  
Intermediate Hosts ◽  
Parasite Strain ◽  
End Products ◽  
Lactate Excretion

Two strains of Hymenolepis diminuta were reared using Tribolium confusum and Tenebrio molitor as intermediate hosts. The carbohydrate metabolism, excreted end products, and adenine nucleotide levels of the adult parasites were compared following 60-min in vitro incubations, in the presence or absence of 5-hydroxytryptamine (5-HT). The strain of parasite, species of intermediate host, and the presence of 5-HT had significant effects on tissue levels of intermediaries in carbohydrate metabolism. Metabolic activity was greater when Tr. confusum was the intermediate host. With Te. molitor, the pool sizes and excretory products were increased compared with Tr. confusum. Discriminant analysis indicated that fructose-1,6-diphosphate (FDP) and phosphoenolpyruvate accounted for 82% of the significant variance between the two parasite strains; succinate accounted for 39% of the differences between hosts; lactate, FDP, pyruvate, and acetate accounted for 45% of the differences owing to 5-HT. Acetate and lactate excretion accounted for 47% of the variance between strains; lactate, acetate, and total end products accounted for 58% of the variance between hosts; lactate, acetate, and total excreted products accounted for 38% of the variance owing to 5-HT. AMP accounted for 20% of the variance between strains; ATP and ADP accounted for 74% of the variance between hosts.

A study of carbohydrate metabolism in the eggs (oncospheres) of the tapeworm, Hymenolepis diminuta, with special reference to glucose

Parasitology ◽  
1993 ◽  
Vol 106 (2) ◽  
pp. 201-209 ◽  
Author(s):  
P. W. Pappas ◽  
G. M. Durka
Keyword(s):  
Molecular Weight ◽  
Special Reference ◽  
Carbohydrate Metabolism ◽  
Incubation Medium ◽  
Hymenolepis Diminuta ◽  
Temporal Shift ◽  
Exogenous Glucose ◽  
End Products ◽  
Inner Envelope

SUMMARYWhen incubated in vitro for 24 h, intact eggs, chemically shelled eggs (obtained by treating intact eggs with NaOCl), activated larvae (eggs in which the outer shell and inner envelope were removed), and oncospheres (activated larvae treated with papain to remove the embryophore) absorb and metabolize radioactive glucose. Intact eggs, which are covered by the impermeable shell, absorb only small amounts of exogenous radioactive glucose, while chemically shelled eggs, activated larvae, and oncospheres absorb much larger amounts. Only very small amounts of the exogenous glucose are incorporated into the ethanol-precipitable carbohydrate fraction (which would include glycogen) by any of the preparations of eggs/larvae. However, the glucose is incorporated into higher molecular weight end-products that are liberated into the incubation medium. There is a temporal shift in the ability of activated larvae and oncospheres to metabolize exogenous glucose. Activated larvae and oncospheres absorb but do not metabolize glucose during the first 8 h post-activation. Between 8 and 16 h post-activation, however, virtually all of the absorbed glucose is metabolized into higher molecular weight end-products that are liberated into the incubation media. This temporal shift suggests that activation of oncospheres and cysticercoid morphogenesis are accompanied by distinct changes in carbohydrate metabolism.

Temporal changes in glucose and carbohydrate metabolism in the oncospheres of the cyclophyllidean tapeworm, Hymenolepis diminuta

Parasitology ◽  
1993 ◽  
Vol 106 (3) ◽  
pp. 317-325 ◽  
Author(s):  
P. W. Pappas ◽  
G. M. Durka
Keyword(s):  
Molecular Weight ◽  
Glucose Metabolism ◽  
Carbohydrate Metabolism ◽  
Glucose Absorption ◽  
Temporal Changes ◽  
Hymenolepis Diminuta ◽  
Temporal Shift ◽  
Carbohydrate Fraction ◽  
Ethanol Extracts

SUMMARYWhen incubated in vitro for 24 h, oncospheres of Hymenolepis diminuta absorb and metabolize radioactive glucose. Between 0 and 12 h post-activation, oncospheres absorb glucose, but glucose is neither metabolized into other carbohydrates nor incorporated into the ethanol-precipitable fraction (which would contain glycogen). Between 12 and 24 h post-activation glucose is incorporated into a number of higher molecular weight carbohydrates that are demonstrable in ethanol extracts of the larvae, as well as the incubation media. Furthermore, measurable amounts of radioactivity are incorporated into the ethanol-precipitable carbohydrate fraction of oncospheres. To determine if these temporal changes in carbohydrate metabolism occurred spontaneously following activation, oncospheres were pre-incubated for 12 h (0–12 h post-activation) in the absence or presence of glucose, and then transferred to media containing radioactive glucose for an additional 12 h (12–24 h post-activation). In these latter experiments, glucose absorption and metabolism between 12 and 24 h post-activation were virtually identical to glucose metabolism in oncospheres that were incubated in radioactive glucose for 0–12 h immediately following activation. Thus, these data do not support the hypothesis that the temporal shift in carbohydrate metabolism occurs spontaneously.

Hymenolepis diminuta: influence of metacestodes on synthesis and secretion of fat body protein and its ovarian sequestration in the intermediate host, Tenebrio molitor

Parasitology ◽  
1986 ◽  
Vol 93 (1) ◽  
pp. 111-120 ◽  
Author(s):  
Hilary Hurd ◽  
C. Arme
Keyword(s):  
Intermediate Host ◽  
Post Infection ◽  
Fat Body ◽  
Tenebrio Molitor ◽  
Hymenolepis Diminuta ◽  
Body Protein ◽  
Concomitant Reduction ◽  
Fat Bodies

SUMMARYFemale Tenebrio molitor infected with metacestodes of Hymenolepis diminuta exhibit elevated concentrations of female-specific proteins in their haemolymph and the origin of these has been investigated. Following a 4 h in vitro incubation with [14C]leucine, fat bodies from non-infected females secreted 13 times more protein than those from females 12 days post-infection. A comparison of the uptake in vivo of radio-isotope labelled amino acids by ovaries from non-infected and infected beetles of various ages revealed no differences; however, a 51·5% decrease in protein sequestration was detected in females 12 days post-infection. Electrophoresis of homogenates of radio-isotope labelled ovaries demonstrated that the majority of label was associated with vitellin sub-units. It is suggested that the decrease in vitellogenin sequestration associated with infection results in an increase in the haemolymph concentration of these proteins despite a concomitant reduction in their secretion by fat bodies. Both fat body synthesis and ovarian sequestration are under juvenile hormone control and it is proposed that metacestodes of H. diminuta may cause a reduction in the concentration of this hormone in the intermediate host.

Effects of Carbohydrate Pulses and pH on Population Shifts within Oral Microbial Communities in vitro

1989 ◽  
Vol 68 (9) ◽  
pp. 1298-1302 ◽  
Author(s):  
D.J. Bradshaw ◽  
A.S. McKee ◽  
P.D. Marsh
Keyword(s):  
Microbial Communities ◽  
Carbohydrate Metabolism ◽  
Oral Bacteria ◽  
The Other ◽  
Carbohydrate Availability ◽  
Oral Microflora ◽  
End Products ◽  
Per Se

A mixed culture chemostat system was used to distinguish between the effects of carbohydrate availability per se and the low pH generated from carbohydrate metabolism on the proportions of bacteria within microbial communities. Nine oral bacteria were grown at pH 7 and pulsed with glucose on ten consecutive days. In one chemostat, the pH was maintained automatically at 7 throughout the experimental period, while in the other, pH control was discontinued for six hours after each pulse. Glucose pulses at neutral pH had little effect on the composition of the microflora. Only the proportions of A. viscosus and V. dispar increased; L. casei and S. mutans remained at low levels (0.2% and 1.0%, respectively). Acetate and propionate were the predominant end-products of metabolism; lactate levels were low. In contrast, when pH was allowed to fall after each glucose pulse, the composition of the microflora altered dramatically. The amounts of L. casei and S. mutans increased both as a proportion of the total count and in absolute numbers, as did V. dispar, whereas the amounts of the other Gram-negative organisms (B. intermedius, F. nucleatum, and N. subflava) and S. sanguis were considerably reduced. Lactate formed a major portion of the metabolic end-products. Successive glucose pulses resulted in both amplified changes in the microflora and a steadily greater rate and final extent of acid production. This is in agreement with the reported shifts in the oral microflora in vivo in response to frequent carbohydrate intake. Analysis of the data strongly suggests that the pH generated from carbohydrate metabolism, rather than carbohydrate availability per se, is responsible for the widely reported shifts in composition and metabolism of the oral microflora in vivo.

Manipulative parasites may not alter intermediate host distribution but still enhance their transmission: field evidence for increased vulnerability to definitive hosts and non-host predator avoidance

Parasitology ◽  
2012 ◽  
Vol 140 (2) ◽  
pp. 258-265 ◽  
Author(s):  
C. LAGRUE ◽  
A. GÜVENATAM ◽  
L. BOLLACHE
Keyword(s):  
Intermediate Host ◽  
Definitive Host ◽  
Parasite Species ◽  
Intermediate Hosts ◽  
Predator Species ◽  
Cottus Gobio ◽  
Host Distribution ◽  
Field Evidence ◽  
Parasite Infections ◽  
Induced Changes

SUMMARYBehavioural alterations induced by parasites in their intermediate hosts can spatially structure host populations, possibly resulting in enhanced trophic transmission to definitive hosts. However, such alterations may also increase intermediate host vulnerability to non-host predators. Parasite-induced behavioural alterations may thus vary between parasite species and depend on each parasite definitive host species. We studied the influence of infection with 2 acanthocephalan parasites (Echinorhynchus truttae and Polymorphus minutus) on the distribution of the amphipod Gammarus pulex in the field. Predator presence or absence and predator species, whether suitable definitive host or dead-end predator, had no effect on the micro-distribution of infected or uninfected G. pulex amphipods. Although neither parasite species seem to influence intermediate host distribution, E. truttae infected G. pulex were still significantly more vulnerable to predation by fish (Cottus gobio), the parasite's definitive hosts. In contrast, G. pulex infected with P. minutus, a bird acanthocephalan, did not suffer from increased predation by C. gobio, a predator unsuitable as host for P. minutus. These results suggest that effects of behavioural changes associated with parasite infections might not be detectable until intermediate hosts actually come in contact with predators. However, parasite-induced changes in host spatial distribution may still be adaptive if they drive hosts into areas of high transmission probabilities.

Human Taenia eggs develop into cysticerci in scid mice

Parasitology ◽  
1997 ◽  
Vol 114 (1) ◽  
pp. 85-88 ◽  
Author(s):  
A. ITO ◽  
W. C. CHUNG ◽  
C. C. CHEN ◽  
M. ITO ◽  
S. ENDO ◽  
...  
Keyword(s):  
New Species ◽  
Animal Models ◽  
Intermediate Host ◽  
Severe Combined Immunodeficiency ◽  
Taenia Saginata ◽  
Combined Immunodeficiency ◽  
Intermediate Hosts ◽  
Experimental Animal Models ◽  
A New Species

The intermediate hosts for Taenia saginata and T. solium are cattle and pigs (and humans for the latter), respectively. In vitro-hatched (but not activated) oncospheres of both Asian Taenia (T. saginata asiatica, a new subspecies of T. saginata or T. asiatica, a new species) and T. solium injected subcutaneously into the backs of mice with severe combined immunodeficiency (scid) developed into fully matured cysticerci. Five-month-old metacestodes of Asian Taenia had no hooklets and were bigger in size than those previously reported and similar to those of T. saginata. Their morphology suggested that the cysticerci were more advanced than those in the intermediate host animals. It is suggested that scid mice are valuable experimental animal models for studying human taeniid cestode infections.

The alcoholic fermentation of glucose by Moniliformis dubius (Acanthocephala), in vitro

1969 ◽  
Vol 172 (1026) ◽  
pp. 65-88 ◽  
Keyword(s):  
Carbohydrate Metabolism ◽  
Alcoholic Fermentation ◽  
Intestinal Helminths ◽  
Aerobic Conditions ◽  
Ethanol Molecule ◽  
End Products

Adult Moniliformis dubius , obtained from freshly killed rats, were incubated in Tyrode’s saline containing known amounts of D-[U- 14 C]glucose under nitrogen or air. The worms appeared to remain in a healthy condition throughout the incubations which lasted for as long as 2.5 h. Nearly all the radioactivity was recovered either within the worms or in the incubation vessel in the form of CO 2 , excretory products and unmetabolized glucose. For incubations in nitrogen of 2.5 h, about 95% of the original glucose was utilized and about 60 % of this was excreted into solution or as CO 2 . Under anaerobic and aerobic conditions, most of the carbohydrate catabolized was recovered as ethanol and CO 2 , the end products of alcoholic fermentation. Small amounts were catabolized to lactate, succinate, acetate and butyrate. During the anaerobic incubations for 2.5 h, nearly half the added glucose utilized by the worms was converted to ethanol and CO 2 and about one ethanol molecule in four was derived from this glucose. The radioactivity recovered as ethanol was twice that recovered as CO 2 . About 97 % of the radioactivity excreted into solution was present as ethanol and lactate in the ratio of approximately 6 molecules of ethanol to one of lactate. The remaining radioactivity was associated with succinate, acetate and butyrate. These results are compared with those obtained by other workers on M. dubius and other acanthocephalan worms. An important function for the excreted ethanol is postulated and the effect of this demonstration of alcoholic fermentation on contemporary concepts on the carbohydrate metabolism of intestinal helminths is discussed.

scholarly journals Efficacy of condensed tannins against larval Hymenolepis diminuta (Cestoda) in vitro and in the intermediate host Tenebrio molitor (Coleoptera) in vivo

2015 ◽  
Vol 207 (1-2) ◽  
pp. 49-55 ◽  
Author(s):  
Suraj Dhakal ◽  
Nicolai V. Meyling ◽  
Andrew R. Williams ◽  
Irene Mueller-Harvey ◽  
Christos Fryganas ◽  
...  
Keyword(s):  
Intermediate Host ◽  
Condensed Tannins ◽  
Tenebrio Molitor ◽  
Hymenolepis Diminuta

Evidence against the hypothesis that metacestodes of Hymenolepis diminuta inhibit corpora allata functioning in the intermediate host, Tenebrio molitor

Parasitology ◽  
1987 ◽  
Vol 95 (1) ◽  
pp. 93-96 ◽  
Author(s):  
Hilary Hurd ◽  
R. J. Weaver
Keyword(s):  
Juvenile Hormone ◽  
Intermediate Host ◽  
Endocrine System ◽  
Tenebrio Molitor ◽  
Hymenolepis Diminuta ◽  
Corpora Allata ◽  
Hormone Production ◽  
Control Female ◽  
And Control

SUMMARYSeveral of the pathophysiological responses made by the beetle Tenebrio molitor, when infected with metacestodes of Hymenolepis diminuta, may be attributed to a parasite-induced reduction in host juvenile hormone titre. It has been suggested that production of this hormone by the corpora allata may be inhibited in parasitized insects. This hypothesis was tested using an in vitro radiochemical assay to compare the biosynthesis of juvenile hormone by single pairs of corpora allata taken from mated 12- and 15-day-old infected and control female insects. The results demonstrate, however, that there was no difference in hormone production associated with metacestode infection. Other possible mechanisms for parasite interference in this host endocrine system are discussed.

Parasite-induced changes in the behaviour of cestode-infected beetles: adaptation or simple pathology?

1996 ◽  
Vol 74 (7) ◽  
pp. 1268-1274 ◽  
Author(s):  
Tonia Robb ◽  
Mary L. Reid
Keyword(s):  
Intermediate Host ◽  
Post Infection ◽  
Tribolium Confusum ◽  
Hymenolepis Diminuta ◽  
Intermediate Hosts ◽  
Larval Form ◽  
Infected Female ◽  
Behavioural Changes ◽  
Male Pheromones ◽  
Induced Changes

Although the cause is often unclear, many parasites alter the behaviour of their intermediate hosts. The larval form of the rat tapeworm, Hymenolepis diminuta, has previously been shown to modify the behaviour of its intermediate host, the flour beetle, Tribolium confusum, in a manner that may be adaptive to the parasite. To test this explanation we observed host behaviours including activity, concealment, and the response to and production of pheromones. Infected female beetles examined both 4–5 and 11–12 days post infection were slower moving and slower to conceal themselves than uninfected conspecifics; however, they did not differ from uninfected individuals in staying concealed. Infection of T. confusum did not affect the production of pheromones by mated and virgin females or the response of females to male pheromones. A second hypothesis for altered behaviours may be that modified behaviours result from pathology. The survivorship of mated infected female beetles was significantly lower than that of infected virgin beetles and uninfected beetles. Thus, both mated status and infection were important factors in survivorship, but only infection had significant effects on the altered behaviours. In this system, therefore, the hypothesis that behavioural changes are due to adaptive manipulation of the host by the parasite is supported.

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