Schistocephalus solidus

Brophy, P.M., Papadopoulos, A., Touraki, M., Coles, B., Korting, W. and Barrett, J. (1989) Purification of cytosolic glutathione transferases from Schistocephalus solidus (plerocercoid) interaction with anthelmintics and products of lipid peroxidation. Molecular and Biochemical Parasitology 35, 1 87-1 95. 

Microstomum lineare Polycelis nigra Diphyllobothrium dendriticum Schistocephalus solidus... 

The major phosphagens found in nature are arginine and creatine but parasitic helminths are unusual in that they possess no detectable phosphagens and none occurs in Hymenolepis diminuta, Moniezia expansa, Ligula intestinalis or Schistocephalus solidus (44). This absence of phosphagens has implications for control of metabolism in cestodes. If... 

Hymenolepis diminuta (adult) Schistocephalus solidus (plerocercoid) Ligula intestinalis (plerocercoid)... 

Some useful, general studies on intermediary metabolism include those on Monieziaexpansa (59-61,664) H. diminuta (400,531,590,612,667) H. microstoma (665, 666) Echinococcus spp. (488, 498, 500) Mesocestoides corti (399) Cotugnia digonopora (618, 619) Schistocephalus solidus (406) and Ligula intestinalis (502). 

Schistocephalus solidus Acetate, propionate of propionate, succinate Propionate, acetate... 

Enzyme Apparent equilibrium constant granulosus0 (protoscoleces, ovine strain) Echinococcus multiloculari (protoscoleces) Moniezia expanseJ (adults) Hymenolepis microstomac (adults) Schistocephalus solidus 1 (plerocercoids) Ligula intestinalif (plerocercoids)... 

This enzyme catalyses the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate (FBP) and is the key regulatory enzyme of glycolysis. The properties of phosphofructokinase (PFK) have been investigated in some detail in adult Moniezia expansa (60) and in plerocercoids of S. solidus (65), where its activity is modulated by a number of compounds, including ATP, AMP, fructose-6-phos-phate, Mg2 +, Mn2 +, K + and NH. In general, the PFKs from both species exhibit properties similar to those of the enzymes from mammalian sources and they probably regulate glycolysis in the same manner as their mammalian counterparts. The inhibitory effects of ATP on the PFK from Schistocephalus solidus and the relief of this inhibition by AMP are shown in Fig. 5.2. 

Fig. 5.2. Plot of the activity of phosphofructokinase from plerocercoids of S. solidus against the concentration of ATP in the presence and absence of 2 mM AMP. The concentration of fructose 6-phosphate was 1 mM. (Reprinted with permission from International Journal for Parasitology, 12, Beis, I. Theophilidis, G. Phosphofructokinase in the plerocercoids of Schistocephalus solidus (Cestoda Pseudophyllidea), 1982 Pergamon Journals Ltd.)...

It has been purified (445) and shares some properties in common with malic enzymes from mammals and birds in being NADP-dependent, heat-stable and able to decarboxylate oxaloacetate. The malic enzyme of H. microstoma also has a marked specificity for NADP (216), contrasting with that of Spirometra mansonoides, which appears to be both NAD- and NADP-linked (220). Malic enzyme has been demonstrated in a range of other cestodes including Mesocestoides corti (399), Schistocephalus solidus (406), Moniezia expansa (60), Echinococcus spp. (500) and L. intestinalis (502). 

In general it is difficult to assess experimentally the importance of the TCA cycle to the energy budget of cestodes, since, as we have seen, partly oxidised metabolites are excreted as end-products even under aerobic conditions. Notwithstanding, there is increasing evidence that, under aerobic conditions, certain cestodes such as Schistocephalus solidus (406) and Echinococcus spp. (500) are capable of catabolising substantial... 

Proteolytic activity has also been detected in Schistocephalus solidus (777), Ligula intestinalis (514, 515,516), Taenia saginata (287, 288), Moniezia expansa (182) and E. granulosus (491). 

Early work has been reviewed in the first edition relevant recent references include Diphyllobothrium dendriticum, D. latum and Diphyllobothrium spp. (172, 421) Ligula intestinalis (269, 421) Schistocephalus solidus (255, 269), Triaenophorus nodulosus(269) T. crassus(269, 712, 713) Spirometramansonoides(64I) S. erinacei (269,330,424-426,972) Eubothrium spp. (269) Haplobothriumglobuliforme (484) Penetrocephalus sp. (119). 

Schistocephalus solidus has its plerocercoid stage in an ectotherm (the fish Gasterosteus aculeatus) and its adult stage in an endoderm (a fish-eating bird) and it serves as an excellent model for the study of temperature adaptation in parasites. Walker Barrett (922,923) have studied the effect of temperature on (a) the activities of the mitochondrial enzyme adenosine triphosphatase (ATPase) and (b) the physical state of mitochondrial membranes in adult and larval S. solidus. 

Fig. 8.15. Monthly variation in the ovarian content of the three-spined stickleback, Gasterosteus aculeatus, parasitised with the progenetic plerocercoids of Schistocephalus solidus. (After Meakins, 1974.)...

Fig. 9.2. Position of the pseudophyllideancestode, Schistocephalus solidus when established in different laboratory hosts. (After McCaig Hopkins, 1963.)...

Pseudophyllidea Schistocephalus solidus, Ligula intestinalis, Spirometra mansonoides. 

Fig. 10.1. Progenetic plerocercoid of the pseudophyllidean Schistocephalus solidus, (a) Enlarged view of plerocercoid showing genital anlagen. (ft) Whole plerocercoid removed from fish.

Fig. 10.2. Culture tube which enables the pseudophyllidean Schistocephalus solidus to undergo insemination during maturation in vitro at 40°C. Fertile eggs are produced only by worms compressed during maturation, a process which enables the cirrus to enter the vagina in each proglottis. Eggs from worms maturing free in the medium produce only infertile eggs. (After Smyth, 1982.)...

Barrett, J. Lloyd, G. M. (1981). A novel phosphagen phosphotransferase in the plerocercoids of Schistocephalus solidus (Cestoda Pseudophyllidea). Parasitology, 82 11-16. 

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