Acceleration of the growth of tetrathyridial populations of Mesocestoides Corti (Cestoda: Cyclophyllidea) by splenectomy

Acceleration of the growth of tetrathyridial populations of Mesocestoides corti (Cestoda: Cyclophyllidea) by splenectomy. International Journal for Parasitology4, 165–168. Experiments with LDF₁ hybrid mice showed that splenectomy 7 days prior to infection, increases the total biomass of tetrathyridial populations of Mesocestoides corti in hosts of both sexes.This increase is accompanied by a decrease in the size of individuals, and by an increase in the percentage of two-suckered and acephalic forms. Splenectomy thus accelerates both the growth of the biomass of populations and the asexual multiplication of the tetrathyridia.     

Histopathological changes in livers of mice infected with tetrathyridia of Mesocestoides corti and exposed to different environmental temperatures

Novak M. 1982. Histopathological changes in livers of mice infected with tetrathyridia of Mesocestoides corti and exposed to different environmental temperatures. International Journal for Parasitology12: 41–45. Observations on the histopathology of the liver of mice infected with Mesocestoides corti and kept for 20 days p.i. (post-infection) at low (5 ± 1°C), room (21 ± 1°C) or high (35 ± 1°C) temperature revealed that the degree of liver pathology was directly proportional to the intensity of liver infection, which in turn was the result of the temperature effect. The most severe pathological changes occured in the heavily infected organs of mice kept at low temperature, followed by less prominent changes in moderately infected livers of mice kept at room temperature and the smallest changes in lightly infected livers of mice kept at high temperature. The pathological changes in infected and uninfected livers of hosts exposed to different environmental temperatures are described and compared.     

A comparative study of the susceptibility of inbred strains of mice to infection with Mesocestoides corti

White T. R., Thompson R. C. A. and Penhale W. J. 1982. A comparative study of the susceptibility of inbred strains of mice to infection with Mesocestoides corti. International Journal for Parasitology12: 29–33. The susceptibility of 6 strains of inbred mice to infection with Mesocestoides corti was studied following both intraperitoneal and oral inoculation of tetrathyridia. The greatest degree of resistance was seen in C57BL/6 mice and this resistance was independent of route of inoculation. The proliferation of the parasite in C57BL/6 mice was compared with a more susceptible strain (CBA/H) on 7, 14, 21, 35 and 60 days post-infection. Although both strains harboured significantly different parasite burdens during the initial period following infection, these differences were no longer apparent by day 60.     

Spontaneous sexual differentiation of Mesocestoides corti tetrathyridia in vitro

Barrett N. J., Smyth J. D. and Ong S. J. 1982. Spontaneous sexual differentiation of Mesocestoides corti tetrathyridia in vitro. International Journal for Parasitology12: 315–322. Tetrathyridia of Mesocestoides corti, from the body cavity of mice, maintained in the laboratory by intraperitoneal infection, were used for in vitro culture. In an initial experiment, after 50 days asexual multiplication in vitro one tetrathyridium spontaneously segmented and developed into a sexually mature adult. Further experiments were carried out in an attempt to determine the conditions favouring segmentation and sexual differentiation. A combination of 5 or 10 ml liquid medium S1OE.H (basically composed of CMRL 1066 and foetal calf serum with supplements) changed every 3 days, in a Leighton tube (19 × 105 mm), rotated at 38°C and gassed with 10 or 20% CO₂, containing between 100 and 200 tetrathyridia, has proved to be most suitable so far. Numerous adult worms with normal male and female genitalia have been obtained in this system. However, segmentation is sporadic, rather than consistent and only a few shelled eggs with hooked oncospheres have so far been obtained, suggesting that impregnation and fertilization in vitro is not fully comparable with that in vivo.     

In vitro development of the strobilar stage of Mesocestoides corti

Thompson R. C. A., Jue Sue L. P. and Buckley S. J. 1982. In vitro development of the strobilar stage of Mesocestoides corti. International Journal for Parasitology12: 303–314. Sexually mature strobilated adults of Mesocestoides corti were grown consistently from undifferentiated tetrathyridia in vitro using a conventional diphasic culture system. Development (growth, strobilisation and maturation) was compared in vitro and in vivo. Although growth and strobilisation were comparable in vitro and in vivo, during the first 18 days, total length and numbers of proglottids decreased in vivo but continued to increase in vitro after day 18. Both male and female reproductive systems appeared to develop normally in vitro and self copulation was frequently observed in cultured worms. However, fully developed oncospheres were not produced in vitro.     

A nuclear magnetic resonance study of the d-[C6]glucose metabolism of Mesocestoides corti tetrathyridia in the absence and presence of monensin

Novak M. and Blackburn B. J. 1988. A nuclear magnetic resonance study of the d-[¹³C₆]glucose metabolism of Mesocestoides corti tetrathyridia in the absence and presence of monensin. International Journal for Parasitology18: 1029–1033. The effect of monensin on the glucose metabolism of Mesocestoides corti tetrathyridia was studied using ¹H and ¹³C nuclear magnetic resonance (n.m.r.) spectroscopy. Signals due to lactate, succinate, acetate and alanine were identified in the spectra of the excretory products of tetrathyridia fed d-[¹³C₆]glucose in vitro for 120 min. Monensin, at a concentration of 10 μm, inhibited glucose uptake across the brush border of the tetrathyridia, as indicated by a higher level of labelled hexose and lower levels of metabolic end products in ionophore-containing culture medium. The possible action of monensin on the glucose transport mechanism is discussed.     

T-cell dependent collagenous encapsulating response in the mouse liver to Mesocestoides corti (Cestoda)

Pollacco S., Nicholas W.L., Mitchell G.F. and Chaicharn Stewart A. 1978. T-cell dependent collagenous encapsulating response in the mouse liver to Mesocestoides corti (Cestoda). International Journal for Parasitology8: 457–462. Experiments with genetically hypothymic mice show that the tetrathyridial larvae of Mesocestoides corti (Cestoda) multiply much more rapidly in the liver than in normal mice. In the hypothymic mouse, collagen fibres are not laid down and the parasite is not encapsulated as it is in the normal mouse. Encapsulation probably restricts the parasite's multiplication, and it is suggested that the failure to encapsulate the parasite accounts for its more rapid multiplication in the hypothymic mouse. Fibrogenesis and encapsulation is restored to hypothymic mice by transferring syngeneic thymus cells, spleen cells or peritoneal exudate cells. It is concluded that the encapsulation of M. corti is a T-cell dependent process.     

Gonadectomy and the development of polycephalic tetrathyridia of Mesocestoides corti (Cestoda: Cyclophyllidea) in mice

The number of polycephalic tetrathyridia present in 150-day-old intraperitoneal larval populations of Mesocestoides corti was markedly increased in mice gonadectomized 1 month prior to infection. This effect was more pronounced in male hosts. In both sexes it was inversely correlated with the size of the populations: the smaller the population, the larger was the number of polycephalic tetrathyridia. These forms are probably produced when the separation of daughter individuals lags behind the growth and organogenesis of these peculiar cestodes.     

Protection against Mesocestoides corti infection in mice treated with zymosan or Salmonella enteritidis 11RX

Toye P. G. and Jenkin C. R. 1982. Protection against Mesocestoides corti infection in mice treated with zymosan or Salmonella enteritidis 11RX. International Journal for Parasitology12: 399–402. Zymosan and Salmonella enteritidis 11RX were found to partially protect mice against infection with the cestode Mesocestoides corti. Thus, mice previously infected with S. enteritidis 11RX contained fewer parasites in the peritoneal cavity compared to normal mice. Mice pretreated with zymosan contained fewer parasites in the peritoneal cavity and in the liver compared to normal mice and this protection was enhanced by the passive transfer of serum from mice chronically infected with M. corti. Examination of mice in the initial stages of infection revealed that the administration of zymosan led to an alteration in parasite location from the peritoneal cavity to the liver.     

The expulsion of Aspiculuris tetraptera and syphacia spp. from mice after anthelmintic treatment

The expulsion of Aspiculuris tetraptera and Syphacia spp. from mice after anthelmintic treatment. International Journal for Parasitology10: 205–211. The effect of four benzimidazoles, piperazine and levamisole on the expulsion of adult Aspiculuris tetraptera and Syphacia spp. from mice is described on a quantitative basis. Levamisole and piperazine were found to initiate expulsion within a few hours, but this ceased by 24 h. Following benzimidazole treatment most pinworms were expelled between 24 and 48 h. Syphacia spp. responded earlier to the benzimidazoles than did A. tetraptera, but later to levamisole; both species responded similarly to piperazine. Only levamisole and mebendazole were completely effective against both species within 24 h, piperazine being the least effective. The in vitro effects of levamisole on the motility and the recovery from drug-induced paralysis of the same nematode species are also reported.     

Cross-protection between the metacestodes of Mesocestoides corti and Taenia crassiceps in mice

Novak M. 1984. Cross-protection between the metacestodes of Mesocestoides corti and Taenia crassiceps in mice. International Journal for Parasitology14: 497–501. Infection with M. corti generated significant resistance against a challenge with T. crassiceps introduced either 2 or 6 weeks after primary infection. Challenge infection with T. crassiceps did not influence primary infection with M. corti. Infection with T. crassiceps protected significantly against challenge with M. corti given 2 weeks but not 6 weeks after the primary infection. Challenge infection with M. corti significantly suppressed primary infection with T. crassiceps.     

Localization and associated histopathology of asexually proliferative Mesocestoides corti tetrathyridia (cestoda) infecting mouse mammary glands

Female mice of pregnant random-bred, or unmated BALB/c groups were exposed per os to Mesocestoides corti tetrathyridia and necropsied at various intervals postexposure. The right posterior subcutaneous fat pad with two mammary glands was removed from each mouse, stained, mounted whole and examined microscopically for localization of worms. The left fat pad/gland set was processed, sectioned and stained using standard histological techniques. In pregnant mice, tetrathyridia were localized primarily in the fat pad's posteroventral lobe. Unmated mice had few worms in the mammary glands or associated fat pads. The difference in infection levels between the two host groups may result from mouse strain difference or the pregnant condition of one group.     

Mesocestoides corti in the rat: The cellular response in the peritoneal cavity of rats infected with Mesocestoides corti

The tetrathyridium (second larval stage) of Mesocestoides corti elicits an extensive cellular response in the peritoneal cavity of rats which was monitored over a period of 40 days following infection. The total white cell count of female Wistar rats rose in the peritoneal cavity during the first 10 days of infection, then declined slowly. Eosinophilia was characteristic, as it is in most helminth infections. Cellular adherence to the surface of some tetrathyridia was noted. In rats infected with a large number of tetrathyridia, many parasites were found trapped in the mesenteries.     

Proteomic Analysis of Excretory-Secretory Products of Mesocestoides corti Metacestodes Reveals Potential Suppressors of Dendritic Cell Functions

Accumulating evidences have assigned a central role to parasite-derived proteins in immunomodulation. Here, we report on the proteomic identification and characterization of immunomodulatory excretory-secretory (ES) products from the metacestode larva (tetrathyridium) of the tapeworm Mesocestoides corti (syn. M. vogae). We demonstrate that ES products but not larval homogenates inhibit the stimuli-driven release of the pro-inflammatory, Th1-inducing cytokine IL-12p70 by murine bone marrow-derived dendritic cells (BMDCs). Within the ES fraction, we biochemically narrowed down the immunosuppressive activity to glycoproteins since active components were lipid-free, but sensitive to heat- and carbohydrate-treatment. Finally, using bioassay-guided chromatographic analyses assisted by comparative proteomics of active and inactive fractions of the ES products, we defined a comprehensive list of candidate proteins released by M. corti tetrathyridia as potential suppressors of DC functions. Our study provides a comprehensive library of somatic and ES products and highlight some candidate parasite factors that might drive the subversion of DC functions to facilitate the persistence of M. corti tetrathyridia in their hosts.     

A single oral treatment with mebendazole for the control of Taenia crassiceps larval infections in rats.

A single oral treatment with mebendazole for the control of Taenia crassiceps larval infections in rats. International Journal for Parasitology9: 73–76. Rats infected with Taenia crassiceps larvae were treated with mebendazole. At a sublethal dose level of 50 mg/kg, a single large oral treatment proved to be markedly more effective in killing cysts than the same amount of drug divided into 10 daily smaller doses. Levamisole promoted a vigorous host cellular response to the intraperitoneal cysts, but when incorporated with mebendazole, it did not enhance the action of the latter drug.     

Anaerobic and aerobic energy metabolism in the larvae (tetrathyridia) of Mesocestoides corti

The tetrathyridia of Mesocestoides corti produce lactate, succinate, acetate, and CO₂ as major carbon-containing end products during in vitro incubation with glucose as the substrate. Differences in the rate of glucose consumption and lactate production under anaerobic or aerobic conditions were observed, but their significance could not be determined. However, succinate production was greatly decreased in the presence of oxygen.The relative activities and intracellular distribution of various enzymes involved in energy-supplying metabolism of the larvae appear to conform to the pathways observed in other parasitic helminths known to produce lactate, succinate, and volatile fatty acids as metabolic end products. Some common features found in this respect are the relatively low pyruvate kinase activity, the presence of a highly active cytoplasmic phosphoenolpyruvate carboxylase and the capability of mitochondrial membrane bound fumarate reductase to reduce fumarate by means of NADH. Although a stimulatory effect of fructose-1,6-diphosphate on the reaction velocity of pyruvate kinase occurred, the absolute activity of this enzyme is very low.Nearly all the enzymes required for Krebs cycle activity are available in the tetrathyridia. Under the assay conditions employed by us, only NAD-dependent isocitrate dehydrogenase could not be demonstrated. The small amounts of ¹⁴CO₂ liberated from 6-¹⁴C-glucose suggest that the cycle in its classical form probably only functions at a very low rate. The incorporation of ¹⁴C from labeled glucose into glycogen indicates the presence of enzymes capable of glycogenesis. The incorporation rate was found to be higher in the presence of oxygen than under anaerobic conditions. On account of the very low NAD-linked glycerol-3-phosphate dehydrogenase activity the glycerolphosphate cycle may be of minor importance for the tetrathyridia.As a result of these studies a scheme for the main carbohydrate dissimilating pathways in the tetrathyridia is proposed and the significance of oxygen with respect to energy-supplying metabolism is discussed.     

Mesocestoides corti in the rat: Comparisons of Mesocestoides corti infections in rats and mice

Infections of M. corti in rats were compared with those in mice. The recoveries of parasites and their distribution were examined for 60 days after infection. During this period continuous and extensive multiplication occurred in mice. In rats there was an initial multiplication of tetrathyridia in the first 10 days followed by a decline in numbers. The relative distribution of tetrathyridia between the peritoneal cavity and liver was similar in both hosts.     

Effects of certain lipid compounds on growth and asexual multiplication of Mesocestoides corti (Cestoda) tetrathyridia

The effects of Williams and Law mixture (W-L), farnesol (juvenile hormone mimics), ecdysterone (molting hormone analog), cholesterol, and stigmasterol on growth and asexual reproduction of Mesocestoides corti larvae in vivo and in vitro were studied. W-L and ecdysterone stimulated an increase in larval asexual reproduction under in vivo conditions, however, cholesterol had no effect on the larvae in vivo. In vitro, cholesterol stimulated a slight increase in reproduction but had no effect on growth; stigmasterol appeared to be somewhat detrimental to the larvae. In vitro, W-L, farnesol, and ecdysterone stimulated by varying amounts an increase in growth (as measured by larval size) and asexual reproduction. Lipid extraction of M. corti larvae and Hymenolepis diminuta adults, followed by a series of thin-layer chromatograms, yielded 2 compounds (I-B and I-D) which affected M. corti larvae in vitro. These 2 compounds stimulated increased growth of the M. corti larvae and to some extent an increase in asexual reproduction.     

Development of simultaneous resistance in Ostertagia circumcincta to thiabendazole, morantel tartrate and levamisole

Le Jambre L.F., Southcott W.H. and Dash K.M. 1978. Development of simultaneous resistance in Ostertagia circumcincta to thíabendazole, morentel tartrate and levamisole. International Journal for Parasitology8: 443–447. A field strain of Ostertagia circumcincta was divided into five strains based on anthelmintic selection in the laboratory. The first strain was selected with 50 mg/kg thiabendazole, the second with 4 mg/kg morantel tartrate, the third with 3.2 mg/kg levamisole, the fourth was not selected and the fifth strain was selected with all three anthelmintics in each generation. The present paper reports the dose response of the eighth generation of the multi-selected strain to thiabendazole, morantel tartrate and levamisole and compares these results with those from the eighth generation of the single selected and unselected strains.In adult O. circumcincta the LD₉₅ for thiabendazole, morantel tartrate and levamisole was 172.0, 9.2 and 8.4 mg/kg respectively in the multiselected strain, compared with corresponding values of > 200, 6.1 and 6.9 for the single selected strains and 14.5, 2.8 and < 1.6 in the unselected parent strain.Multiple selection with three anthelmintics was associated with an increase in O. trifurcata from less than 0.1 % in the unselected strain to 16% in the multi-selected strain.An increase in inhibition was a feature of both multiple selection and selection by levamisole alone. The parent strain had less than 0.1 % inhibition but the incidence increased to 16% in the levamisole selected strain and to 2% in the multi-selected strain. Approximately 8% of the inhibited larvae in the levamisole selected strain were resistant to dose levels of levamisole from 1.6 to 8.0 mg/kg. Resistance in inhibited larvae was further enhanced in the multi-selected strain and after eight generations 100% of larvae in this strain were resistant to all dose levels up to 100 mg/kg thia-bendazole, 20 mg/kg morantel tartrate and 8 mg/kg levamisole. Apparently when selected with anthelmintics that are less effective against larvae than adults, O. circumcincta responds by increasing the percentage and resistance of inhibited larvae.     

Mesocestoides corti: cation concentration in calcareous corpuscles of tetrathyridia grown in vitro

The tetrathyridia larval stage of the cestode Mesocestoides corti has been maintained for 5 days in vitro in the presence of Cr(III), Cu(II), Ga(III), In(III) T1(I), VO(II), Zn(II), and Zr (IV) cations. With the exception of the VO(II) culture, all tetrathyridia concentrated these cations in the calcareous corpuscles. Vanadium, as the vanadyl ion, appeared to have a toxic effect on the organisms and no vanadium was detected in these corpuscles by emission spectrographic analysis. Incorporation of the other ions has been shown by emission spectrographic analysis and, in the case of Ga, In, and T1, compounds containing these ions were identified by X-ray powder diffraction. The identification by emission spectrography of cations whose compounds were not identifiable by X-ray diffraction has led to the speculation that these ions may have been incorporated into the organic portion of the calcareous corpuscles rather than the inorganic portion.