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PubMed1991

Possible formation of calcareous corpuscles by the brood capsule in secondary hepatic metacestodes of Echinococcus multilocularis.

In secondary hepatic metacestodes of Echinococcus multilocularis at 156 days post-infection, a few small structures exhibiting a central body and a small number of concentric layers were found on the outer surface of the brood capsule, and many such structures were detected on the germinal layer. As these structures are believed to represent immature calcareous corpuscles, we think that not only germinal layer cells but also brood capsule cells of E. multilocularis metacestodes can form calcareous corpuscles.

Animals↗
PubMed1986

In vitro survival of Echinococcus granulosus protoscolices in several media, at +4 degrees C and +37 degrees C.

As a first step towards hydatid disease control, the in vitro survival of protoscolices of Echinococcus granulosus was investigated for various media and temperatures. Higher percentage survival was obtained than previously reported: at 4 degrees C, 100% survival was obtained for 20 days in medium 199 (GIBCO) and for 25 days in hydatid fluid from the host of origin. Maximal survival was 30% at 55 days in these conditions. Flame cell activity was the criterion of choice for viability. At 37 degrees C survival rates were lower and morphological changes in protoscolices were observed.

Animals↗
PubMed1989

Echinococcus granulosus of camel origin: development in dogs and parasite morphology.

The developmental characteristics of Echinococcus granulosus of camel origin were studied in four dogs artificially infected with protoscolices originating from hydatid cysts isolated from the lung of a camel (Camelus dromedarius). Two dogs each were necropsied 34/35 and 41 days post-infection (p.i.); one dog had a low worm burden and the others were heavily infected (27,625-41,150 worms). At day 35 p.i., 20% of the parasites had developed three segments and the uterus of the vast majority of the total population was full of developing eggs in the terminal segment. At day 41, up to 58% of the parasites contained mature eggs (embryonated eggs with fully developed, "thick-shelled" embryophores). Morphological studies revealed the following major characteristics for 35 day-old worms: the mean length of the terminal segment accounted for 54% of the total worm length; the position of the sexually mature segment was always terminal; the female reproductive system possessed an elongated ovary with compact lobules; the female ducts were also compact; the Mehlis' gland was covered by the vitelline gland and the testes were distributed throughout the segment, with 1 row posterior to the vitelline gland. The camel isolate can readily be distinguished from the horse and sheep strains, but it is similar to the cattle strain in some respects, particularly in its precocious development. However, the camel isolate differs from the cattle strain in the position of the sexually mature segment, arrangement of the testes and structure of the female reproductive system. As in the cattle strain, the metacestodes in the principal intermediate host are mostly localised in the lung and have a high fertility rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Further evidence for the occurrence of a distinct strain of Echinococcus granulosus in European pigs.

The morphology, adult development and genetic characteristics of Echinococcus granulosus isolated from pigs in Poland were examined and compared with those of other recognised strains of E. granulosus. The isolates were characterised by their distinct morphology, rapid maturation and unique DNA hybridisation profiles. The form of E. granulosus that occurs in European pigs may therefore be a distinct strain that can be separated morphologically and genetically from other strains and that exhibits features of epidemiological significance, including a rapid rate of development in dogs and an apparent low infectivity to humans and domestic ungulates.

Animals↗
PubMed1993

Analysis of taeniid antigens using monoclonal antibodies to Echinococcus granulosus antigen 5 and antigen B.

Antigens derived from Echinococcus granulosus, Taenia hydatigena and T. pisiformis cyst fluids, T. solium cysticerci, E. multilocularis protoscoleces and E. vogeli cyst membranes were examined by enzyme-linked immunosorbent assay (ELISA) and immunoelectrophoresis (IEP) using four monoclonal antibodies (mAb) to E. granulosus antigen 5 (Ag5) and antigen B (AgB). Anti-Ag5 mAbs 24.14 and 61A12 reacted strongly with T. hydatigena and T. pisiformis cyst fluids and, to a lesser degree, anti-AgB MAbs 31.15 and 39B3 also displayed some reaction with these antigens in ELISA. The formation of a modified arc 5 band between Anti-Ag5 mAbs and T. hydatigena cyst fluid (THCF) in IEP further confirms the existence of Ag5 in T. hydatigena cyst fluid. However, the inability of THCF and T. pisiformis cyst fluid (TPCF) to form an AgB band as well as that of TPCF to form an arc 5 band with mAbs in IEP does not exclusively prove the lack of AgB in THCF and TPCF or the lack of Ag5 in TPCF. The absence of a reaction of mAbs with T. solium, E. multilocularis and E. vogeli antigen preparations in ELISA or IEP would suggest that these mAbs may recognise epitopes different from those of T. solium, E. multilocularis and E. vogeli parasites; this might be exploited for specific differentiation of E. granulosus.

Animals↗
PubMed1995

Cloning and immunological characterisation of Echinococcus granulosus ferritin.

A cDNA clone of Echinococcus granulosus has been isolated from an expression library screened with sera from cystic echinococcosis patients. The deduced amino acid sequence shows 56% homology to the heavy chain of human ferritin. E. granulosus ferritin contains 173 amino acid residues and has a calculated molecular weight of 19830 Da and a statistical isoelectric point of 7.6. Functionally important amino acid residues of the ferroxidase centre are conserved in comparison with other ferritins. In vitro-translated E. granulosus ferritin was tested for its diagnostic potential by immunoprecipitation. The antigenic reactivity exhibited a good potential for the further development of E. granulosus ferritin as an immunodiagnostic tool for human hydatidosis.

Amino Acid Sequence↗
PubMed1995

Anti-tubulin immunohistochemistry study of Echinococcus granulosus protoscolices incubated with albendazole and albendazole sulphoxide in vitro.

Tubulin content was immunohistochemically studied in Echinococcus granulosus protoscolices incubated with albendazole and albendazole sulphoxide alone or in combination. Tubulin immunoreactivity was very patent in the control protoscolices and was mainly located in the sucker region and the invagination channel of protoscolices. Treated protoscolices always showed less immunoreactivity than did control protoscolices. We concluded that albendazole and its metabolite albendazole sulphoxide produce tubulin alterations in E. granulosus protoscolices.

Albendazole↗
PubMed1992

Metabolites of alveolar Echinococcus as determined by [31P]- and [1H]-nuclear magnetic resonance spectroscopy.

[31P]-Nuclear magnetic resonance (NMR) in vivo spectra of Echinococcus multilocularis cysts growing subcutaneously in Meriones unguiculatus showed prominent signals due to phosphomonoesters (PME), phosphodiesters (PDE), inorganic phosphate (Pi) and the alpha, beta and gamma phosphate groups of adenosine triphosphate (ATP). The internal pH of the parasite cysts was 6.7-6.8. The 31P spectra of extracts of these subcutaneous cysts showed peaks identified as glucose-6-phosphate (Glu-6-P), glycerol-3-phosphate (Gly-3-P), phosphorylethanolamine (PE), adenosine-5'-monophosphate (5'-AMP), nicotinamide adenine dinucleotide phosphate (NADP), phosphorylcholine (PC), Pi, glycerolphosphorylethanolamine (GPE), glycerolphosphorylcholine (GPC), phosphoenolpyruvate (PEP), adenosine diphosphate (ADP), ATP and diphosphodiesters (DPDE). These metabolites were also detected at comparable concentrations in the extracts of intraperitoneally grown cysts. In addition, significantly more phosphocreatine (PCr), probably of host origin, was detected in the subcutaneous cysts than in the intraperitoneal cysts. [1H]-NMR spectra of cyst extracts revealed that parasites grown in the abdominal cavity contained significantly less glucose but significantly more succinate, acetate, alanine and beta-hydroxybutyrate. Glycogen, creatine, glycine, taurine, betaine, cholines and lactate were present at similar concentrations in cyst material from both locations.

Adenosine Triphosphate↗
PubMed1995

Effects of Isoprinosine on Echinococcus multilocularis and E. granulosus metacestodes.

An in vivo study of the effect of Isoprinosine on Echinococcus multilocularis and E. granulosus metacestodes (Cestoda) was performed. Short- and long-term treatments with different doses were tested in experimental hosts: jirds for E. multilocularis and mice for E. granulosus. Modifications in the weight of animals as well as macroscopical and ultrastructural aspects were registered for each animal group. The results obtained showed a considerable ultrastructural alteration in E. multilocularis metacestodes after short-term treatment with the highest dose, and the tissue transplants were negative. In E. granulosus cysts the ultrastructural damage was also very important and its severity increased as the dose was raised. For the two parasites, the macroscopical aspect and weight of the lesions were profoundly changed.

Abdominal Muscles↗
PubMed1989

Development of the tegument of Echinococcus granulosus (Cestoda) protoscoleces during cystic differentiation in vivo.

During the first 4 days following infection, early tegumentary changes are confined to the protoscolex soma of Echinococcus granulosus, the thick glycocalyx being lost and the blunt elevations, flattened. The Golgi complexes within the tegumentary cytons produce T2 vesicles that increase in number in the tegument from days 4 to 12, whereas T1 vesicles decline. Spineless, truncated microtriches develop at the somal surface, and the laminated layer starts to form around the developing cyst from days 20-40 onwards. T2 vesicles do not appear to be involved in its formation and decline in number. Two additional vesicle types participate in the production of the laminated layer: T4 vesicles contribute to the carbohydrate matrix, and 'G' vesicles form granular accumulations. Cystic differentiation is completed after 2-3 months, when the spined microtriches and rostellar hooks of the scolex are shed into the laminated layer and replaced by truncated microtriches. These ultrastructural changes are discussed with respect to parasite survival.

Animals↗
PubMed1993

Ultrastructure and microanalyses of the calcareous corpuscles of the protoscoleces of Echinococcus granulosus.

The calcareous corpuscles of the protoscolex stage of Echinococcus granulosus are irregularly spherical or ovoid in shape and have a diameter ranging between 2 and 16 microns. The central region of immature corpuscles is composed of an electron-lucent matrix containing granular deposits and, in more mature corpuscles, paired membrane lamellae. Energy-dispersive X-ray microanalysis of sectioned immature corpuscles demonstrated calcium, magnesium and phosphorus, whilst a quantitative analysis indicated the presence of calcium and magnesium at 142.7 and 41.3 mg/g dry weight, respectively, and inorganic phosphate at 18.0 mg/g. Assuming that the anion is predominantly carbonate, the molar ratio of Ca:Mg:HPO4(2-):CO3(2-) is 1:0.48:0.08:1.41. X-ray diffraction patterns obtained from preparations of whole corpuscles indicated a poorly crystalline material including the mineral calcite. X-ray absorption near-edge spectra of corpuscles, taken over the phosphorus K edge, resembled those of brushite (CaHPO4.2H2O) and suggest that the phosphate, within the corpuscles, is present in an amorphous, hydrated form that could be readily solubilised and mobilised for the metabolic processes of the organism.

Animals↗
PubMed1995

Immunology and morphology studies on the proliferation of in vitro cultivated Echinococcus multilocularis metacestodes.

The larval stage of Echinococcus multilocularis causes alveolar echinococcosis (AE) in various mammals, including humans. Traditionally metacestodes are maintained in the laboratory by serial transplantation passages into susceptible animals such as mice or gerbils. However, in animal models it has always been difficult to draw definite conclusions about the factors modulating metacestode differentiation, and investigations on gene expression and respective regulation have been hampered by the complexicity of the host-parasite interplay. This paper describes the maintenance and proliferation of E. multilocularis metacestodes as well as the formation of protoscolices in a chemically defined medium devoid of host influence. The interactive role of a heterologous human cell line (CACO2) in the in vitro development of metacestodes was also assessed. The morphology and ultrastructure of in vitro-generated metacestodes was studied using scanning (SEM) and transmission electron microscopy (TEM). Different cultivation procedures were analyzed in terms of expression of B- and T-cell epitopes and of the relevant laminated layer-antigen Em2; the exact localization of this antigen was further demonstrated by immunogold electron microscopy.

Animals↗
PubMed1993

Lymphocyte engraftment conveys immunity and alters parasite development in scid mice infected with Echinococcus multilocularis.

Severe combined immune-deficient (scid) mice, which lack functional B- and T-lymphocytes, were infected with Echinococcus multilocularis larval tissue before or after reconstitution with lymphoid cells from immunocompetent donor mice. Untreated scid mice were highly susceptible to E. multilocularis infection, while scid mice reconstituted with purified lymphocytes derived from either infected or uninfected normal donor mice were capable of almost totally suppressing the growth of the larval cyst mass. The somatic development of the larval parasite varied according to the infection status of the cell donor, with protoscolices forming in scid mice reconstituted with cells from uninfected normal mice but not in those receiving cells from infected normal mice. These results confirm earlier findings that lymphocytes are important in suppressing the growth of E. multilocularis cysts in the intermediate host and also indicate that protoscolex development is influenced by lymphocytes or their products.

Animals↗
PubMed1993

Studies on Echinococcus granulosus using the scanning electron microscope. I. Preparations of the parasite for infection of the final host.

The development of the protoscoleces of Echinococcus granulosus was studied after chemical stimulation, which mimics that offered by the final host. This stimulation resulted in some morphological changes in the parasite and to its evagination. These changes prepare the parasite to infect the intestine of its final host. The external morphology of the protoscolex body and of the germinal layer of the cyst and brood capsule were studied using the scanning electron microscope (SEM). Findings were related to other studies using the transmission electron microscope (TEM). The morphology of the flame cell is described and four cases of teratogenesis are reported.

Animals↗
PubMed1993

Studies on Echinococcus granulosus using the scanning electron microscope. II. The hooks.

The morphology of the hooks of Echinococcus granulosus at the protoscolex level was studied by means of scanning electron microscopy. Hooks were uncovered in situ and also freed from the rostellum so as to study them in detail. There were two types of hooks: those of the upper row, which were larger and had a projecting, rounded stout guard, and those of the lower row, which were smaller and had a flattened guard. These and other differences in the morphology of the two types of hooks were studied and related to the differences in their function.

Animals↗
PubMed1994

Echinococcus multilocularis: in vitro interactions between protoscolices and Kupffer cells.

Echinococcus multilocularis protoscolices collected from experimentally infected jirds were incubated for 2 weeks in rat hepatic cell cultures cocultivated with or without feeder cells (BALB/c 3T3 and IAR 20). Scanning and transmission electron microscopy studies were performed during the course of the culture period. Kupffer cells (Kc) were seen adhering to the anterior and posterior ends of the protoscolices. Some protoscolices were fixed to the cell monolayer by a cluster of Kc adhering to the posterior end of the parasite. These cells were phagocytosing the glycocalyx and the electron-dense distal end of the microthrix of the protoscolex tegument. An alteration in the superficial tegumental cytoplasm with extensive mitochondrial damage was also noted. The properties expressed by Kc against protoscolices in vitro might also be relevant for proliferation of metacestodes in vivo.

Animals↗
PubMed1993

Paramyosin of Echinococcus granulosus: cDNA sequence and characterization of a tegumental antigen.

A lambda ZAPII cDNA library of Echinococcus granulosus larvae was expressed in Escherichia coli SURE cells. Screening of the library with a rabbit antiserum raised against total larval antigen yielded several immunoreactive clones. For analysis of the nucleotide sequence, in vivo excision into pBlueskript was carried out and the 3' end of the cloned insert was sequenced. Three of these clones exhibited identical nucleotide sequences, suggesting expression of identical genes. The complete nucleotide sequence of the largest clone, EG36, with a 3.4-kb insert was determined, presenting an open reading frame of 2.59 kb. The predicted amino acid sequence showed 71.4% identity to the Schistosoma mansoni paramyosin and a significant homology to a 17 amino-acid peptide sequence from antigen B of Taenia solium. From these data we conclude that EG36 is the paramyosin of E. granulosus. For protein purification, the coding sequence of the cDNA was amplified by polymerase chain reaction and ligated in frame into the expression vector pGEX-3X. Affinity-chromatography-purified GST fusion protein was used to induce a polyclonal rabbit antiserum. Immunoblot analysis revealed the expression of a 97-kDa protein by the E. coli clone and that of a protein with a similar molecular weight in protoscolices from E. granulosus and E. multilocularis as well as in E. granulosus cyst fluid. Immunofluorescence studies showed that EG36 was localized throughout the tegument of E. granulosus and E. multilocularis larvae. Sera from patients suffering from echinococcosis, schistosomiasis, and neurocysticercosis reacted with the purified fusion protein when tested in an enzyme-linked immunosorbent assay.

Amino Acid Sequence↗
PubMed1994

Serotoninergic and peptidergic nerve elements in the protoscolex of Echinococcus granulosus (Cestoda, Cyclophyllidea).

The localisation and distribution of 5-hydroxytryptamine (5-HT, or serotonin) and neuropeptides in the nervous system of the protoscolex of the hydatid organism Echinococcus granulosus were determined by an indirect immunofluorescence technique. Nerve-cell bodies immunoreactive for 5-HT occurred in the lateral ganglia and in association with the lateral longitudinal nerve cords. 5-HT immunostaining was also evident in the central nerve ring, in the rostellar nerves and in the nerve plexus innervating the suckers. Of the antisera used to screen the protoscolex for neuropeptide immunoreactivity (IR), immunostaining was obtained with those raised against pancreatic polypeptide (PP), peptide YY (PYY), substance P (SP), peptide histidine isoleucine (PHI) and vasoactive intestinal peptide (VIP). The most extensive pattern of IR occurred with antisera to PP and PYY. Immunoreactive nerve elements were evident in the lateral ganglia, central nerve ring, rostellar nerves, rostellar ganglia, sucker plexus and longitudinal nerve cords. The distribution of SP-, PHI- and VIP-IRs was more restricted: SP-IR occurred in the lateral ganglia and sucker nerves, whilst PHI- and VIP-immunoreactive nerve elements were associated with the lateral longitudinal nerve cords. Protoscoleces cultured in vitro for 29 days were also examined and neuroanatomical changes noted. A greater development of the longitudinal nerve cords and their cross-connectives in the body of the worm was evident, and a group of nerve cells were seen to develop at the posterior end of the main lateral nerve cords.

Animals↗