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H. Zahner - One of the best experts on this subject based on the ideXlab platform.
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Litomosoides carinii: extraction of the microfilarial sheath components and antigenicity of the sheath fractions
Parasitology Research, 1992Co-Authors: G. Bardehle, H. H. Schott, G. Schares, M. Hintz, D. Linder, S. Stirm, H. ZahnerAbstract:Microfilarial sheaths of Litomosoides carinii were isolated and extracted with 2% sodium dodecyl sulfate (SDS) and 5% 2-mercaptoethanol (2ME). Extraction with SDS alone did not alter the ultrastructure of the sheaths and yielded five polypeptides (27–67 kDa) that were not recognized by antibodies of infected hosts but reacted with antibodies to host-serum proteins. 2ME treatment caused partial solubilization of the sheaths (45% as determined by amino acid analysis), which could be further improved by combining 2ME with SDS. The remainder showed filamentous/threadlike structures on electron microscopic examination. As compared with whole sheaths, the insoluble proportion was markedly enriched in alanine and cysteine but contained less galactosamine, serine, and threonine. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of 2ME/SDS-extractable components showed 12–16 bands of 14>120 kDa. A predominant component had an apparent molecular mass of 22 kDa. Two bands (42 and 120 kDa) could be stained with Coomassie blue but showed “negative” staining when gels were stained with silver. Several components (but not the 22-kDa polypeptide) bore phosphocholine epitopes. Apart from the negatively staining bands, most of the 2ME-soluble sheath components were recognized by antibodies of L. carinii -infected Mastomys coucha . Except for several polypeptides that had been unspecifically recognized by IgM, the antibody response to sheath components started at the end of the prepatent period.
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On the pathogenesis of anaemia and leukopenia in filarial (Litomosoides carinii) infection of Mastomys natalensis.
Zentralblatt fur Veterinarmedizin. Reihe B. Journal of veterinary medicine. Series B, 1991Co-Authors: Claudia Ziegler, Ilse Käufer-weiss, H. ZahnerAbstract:Summary Mastomys natalensis infected with the filarial parasite Litomosoides carinii show anaemia and leukopenia. Alterations start with the onset of microfilaraemia. Anaemia is temporally macrocytic (up to 80 days after infection), subsequently normocytic and hypochromic, accompanied by reticulocytosis. Increased intravascular haemolysis (i) and functional disorders of the haemopoetic system (ii) are involved in the pathogenesis. i: Circulating erythrocytes showed increased osmofragility. Hypoglycaemia demonstrated in parasitaemic animals may be one reason. ii: Histological and electron microscopical investigations of the bone marrow revealed markedly enhanced haemopoiesis in infected animals. However, a high proportion of cells was found pathologically altered already beginning in the late prepatency and increasing in the further course of infection. Thus, dyshaemopoiesis may result in the production of morphologically and functionally aberrant cells which are rapidly eliminated by the MPS which is highly activated in L. carinii infected M. natalensis.
R. K. Chatterjee - One of the best experts on this subject based on the ideXlab platform.
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The Uptake of 5-Hydroxytryptamine by Litomosoides carinii and the Effect of Antifilarials
2015Co-Authors: K. Saxena, Ramanuj Sen, R. K. Chatterjee, S. GhatakAbstract:Abstract: Litomosoides carinii, the filarial parasite of cotton rat (Sigmodon hispidus), has been shown to possess both high and low affinity uptake mechanisms for 5-hydroxytryp-tamine (5-HT). The Michaelis-Menten constant (Km) and Vmaxvalues for high affinity system were 1.9ƒÊM and 1.25ÊM/g/2 min, while the corresponding values for the low af-finity system were 10ƒÊM and 6.6M/g/2 min respectively. The uptake mechanism was found to be temperature dependent and was inhibited by microfilaricides-diethylcar-bamazine and centperazine, the latter exhibiting more pronounced effect. The filaria
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Antioxidant system of Litomosoides carinii and Setaria cervi: effect of a macrofilaricidal agent.
Veterinary parasitology, 1992Co-Authors: Sanjay Batra, R. K. Chatterjee, Vishwa M.l. SrivastavaAbstract:Filarial parasites, Litomosoides carinii and Setaria cervi, showed great susceptibility to the oxidants generated in vitro by the xanthine/xanthine-oxidase system. In order to counteract such injurious effects, both the filariids possessed an active antioxidant enzymes system. Superoxide dismutase, catalase and glutathione peroxidase were detected in appreciable amounts but glutathione reductase and glucose-6-phosphate dehydrogenase in very low quantities. The former three enzymes were also found to be released by the parasites into the ambient medium. The released enzymes may be responsible for scavenging the host-generated oxidants present in the immediate surroundings of the parasites and thereby enabling them to live comfortably in the host. This Institute-based antifilarial agent namely Compound 82/437 which is 2,2'-dicarbomethoxylamino-5,5'-dibenzimidazolylketone, markedly inhibited catalase and glutathione peroxidase of both L. carinii and S. cervi. The compound, therefore, appears to render the filariids prone to H2O2 toxicity leading to penultimate damage.
Horst Zahner - One of the best experts on this subject based on the ideXlab platform.
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Brugia spp. and Litomosoides carinii: identification of a covalently cross-linked microfilarial sheath matrix protein (shp2).
Molecular and biochemical parasitology, 1995Co-Authors: Jörg Hirzmann, Horst Zahner, Stephan Stirm, Martin Hintz, Franz Josef Conraths, Achim Schnaufer, Gerd HobomAbstract:A microfilarial sheath protein gene (shp2) coding for the major constituent of the insoluble, cross-linked sheath remnant (SR) from Brugia malayi, Brugia pahangi and Litomosoides carinii has been cloned and sequenced, based on peptide partial amino-acid sequences. All three closely related single-copy shp2 genes in the two genera carry a single intron in identical position; shp2 mRNAs are post-transcriptionally modified by both cis-splicing and trans-splicing. In accordance with their extracellular destinations the encoded proteins include signal peptide sequences; molecular masses of approx. 23 kDa are hence predicted for the mature secreted polypeptides. In their structures sheath matrix proteins shp2 may be regarded as extreme cases of a modular constitution, since these proteins largely consist of two different segments of multiple sequence repetitions, PAA and QYPQAP (or QYPQ), separated by elements of unique sequence. Extreme insolubility and cross-linking are likely to originate from these repetitive sequences within shp2, and to constitute the basic properties of a microfilarial matrix largely consisting of an shp2 network.
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Litomosoides carinii: macrofilariae-derived glycolipids--chromatography, serology and potential in the evaluation of anthelminthic efficacy.
Parasite immunology, 1994Co-Authors: Stefan Baumeister, Horst Zahner, Roger D. Dennis, R. Klünder, G. Schares, E. GeyerAbstract:SUMMARY A preliminary characterization of the glycolipids of Litomosoides carinii macrofilariae, resolved according to their chromatographic, chemical and serological properties, has been performed. Emphasis has been placed on the neutral fraction glycolipids. These are separable on thinlayer chromatography into two groups of fast and slow migrating band components, that differ in their migration, differential chemical staining and serological traits, respectively. Serological analyses have been accomplished by thin-layer chromatography immunostaining and ELISA. Only components of the slow migrating band group react with infection serum from Litomosoides carinii-infected Mastomys coucha. Cross-reactivity experiments with homologous and heterologous infection sera of various helminthiases indicate that, epitopes bound to the neutral glycolipid fraction show structural similarity within the Nematoda, but not to the Cestoda or Trematoda. The dynamic development of specific Ig-, IgG- and IgM-anti-neutral glycolipid fraction antibody levels were correlated with the different progression of L. carinii and Brugia malayi infections in the multimammate rat, Mastomys coucha. The reduction in the dynamics of IgG- and IgM-antibody levels on chemotherapeutic treatment with the filaricides flubendazole and CGP 20376 has been related to their macrofilaricide-activity.
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Litomosoides carinii microfilarial sheaths: Partial amino-acid sequences of several major polypeptide constituents
Molecular and biochemical parasitology, 1994Co-Authors: Martin Hintz, Horst Zahner, H. H. Schott, Dietmar Linder, Jörg Hirzmann, Gerd Hobom, Friedrich Lottspeich, Franz Josef Conraths, Stephan StirmAbstract:Isolated sheaths from Litomosoides carinii microfilariae were disintegrated by reduction with dithiothreitol and were 14C-carboxymethylated. Five major sheath proteins thus solubilized were purified by size exclusion chromatography and reversed-phase HPLC (rpHPLC). Proteolytic fragments of complete sheaths and of the single sheath proteins were isolated by rpHPLC and were N-terminally sequenced. A library of 27 partial sheath polypeptide sequences was thus established, 21 of which could be assigned to three L. carinii sheath structural genes (shp1,2, and 3/3a) isolated on the basis of this and of previous amino acid sequence information. The remaining peptides document the presence of at least one additional major sheath constituent.
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Ivermectin-induced cell-dependent lethal effects on Litomosoides carinii microfilariae in vitro.
Tropical medicine and parasitology : official organ of Deutsche Tropenmedizinische Gesellschaft and of Deutsche Gesellschaft fur Technische Zusammenar, 1994Co-Authors: Horst Zahner, Schmidtchen DAbstract:Ivermectin affected the motility of Litomosoides carinii microfilariae in vitro in a dose dependent manner but did not completely immobilize the larvae and had no lethal effects when tested up to a concentration of 1000 ng/ml. However, killing of microfilariae was induced by ivermectin in vitro in the presence of spleen cells of Mastomys coucha or rats within 14 h. Optimum effects occurred at drug levels of 10-100 ng ivermectin/ml. Addition of infection serum led to increased cytotoxicity when compared with normal serum. Pretreatment in vitro of L. carinii microfilariae with ivermectin in cell-free medium and subsequent exposure to spleen cells caused also cytotoxic effects which appeared to be accelerated in comparison with simultaneous exposure of microfilariae to ivermectin and cells. Pretreated microfilariae, injected intravenously into naive M. coucha were rapidly eliminated from the blood of the recipients. These results suggest that the microfilariae become altered by the drug and thus susceptible to cell-mediated cytotoxic effects. Cytotoxicity did not depend on the attachment of cells to L. carinii microfilariae and was also induced when targets and effector cells were separated by membranes impermeable for cells. Thus ivermectin-induced cellular cytotoxicity to L. carinii microfilariae is at least partly mediated by soluble factors released by effective cells.
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The gene coding for the major sheath protein of Litomosoides carinii microfilariae, gp22, is transcribed in oocytes and embryonic cells.
Molecular and biochemical parasitology, 1993Co-Authors: Franz Josef Conraths, Gerd Hobom, Birgit Schützle, Gereon Schares, Heike Christ, Horst ZahnerAbstract:The transcription and translation of the gene encoding gp22, a major constituent of the microfilarial sheath of the filarial parasite Litomosoides carinii were studied by in situ hybridisation and immunohistology. Transcription of the gp22 gene is confined to oocytes and embryos in the reproductive organs of adult female worms. It starts in oocytes in the rhachis zone, is maximal in multicellular embryos and decreases slowly as the microfilariae develop. Blood microfilariae lack the gp22 transcript. The gp22 gene product is first detectable in parasites recovered on day 32 post infection. Expression of gp22 begins in multicellular embryos in the uteri of mature female worms and can be detected in all further developed intrauterine stages. The gp22 gene product appears to be exported by the embryonic cells and becomes integrated into the sheath where it may contribute to the flexibility of the latter structure.
S. Ghatak - One of the best experts on this subject based on the ideXlab platform.
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The Uptake of 5-Hydroxytryptamine by Litomosoides carinii and the Effect of Antifilarials
2015Co-Authors: K. Saxena, Ramanuj Sen, R. K. Chatterjee, S. GhatakAbstract:Abstract: Litomosoides carinii, the filarial parasite of cotton rat (Sigmodon hispidus), has been shown to possess both high and low affinity uptake mechanisms for 5-hydroxytryp-tamine (5-HT). The Michaelis-Menten constant (Km) and Vmaxvalues for high affinity system were 1.9ƒÊM and 1.25ÊM/g/2 min, while the corresponding values for the low af-finity system were 10ƒÊM and 6.6M/g/2 min respectively. The uptake mechanism was found to be temperature dependent and was inhibited by microfilaricides-diethylcar-bamazine and centperazine, the latter exhibiting more pronounced effect. The filaria
G. Bardehle - One of the best experts on this subject based on the ideXlab platform.
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Litomosoides carinii: extraction of the microfilarial sheath components and antigenicity of the sheath fractions
Parasitology Research, 1992Co-Authors: G. Bardehle, H. H. Schott, G. Schares, M. Hintz, D. Linder, S. Stirm, H. ZahnerAbstract:Microfilarial sheaths of Litomosoides carinii were isolated and extracted with 2% sodium dodecyl sulfate (SDS) and 5% 2-mercaptoethanol (2ME). Extraction with SDS alone did not alter the ultrastructure of the sheaths and yielded five polypeptides (27–67 kDa) that were not recognized by antibodies of infected hosts but reacted with antibodies to host-serum proteins. 2ME treatment caused partial solubilization of the sheaths (45% as determined by amino acid analysis), which could be further improved by combining 2ME with SDS. The remainder showed filamentous/threadlike structures on electron microscopic examination. As compared with whole sheaths, the insoluble proportion was markedly enriched in alanine and cysteine but contained less galactosamine, serine, and threonine. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of 2ME/SDS-extractable components showed 12–16 bands of 14>120 kDa. A predominant component had an apparent molecular mass of 22 kDa. Two bands (42 and 120 kDa) could be stained with Coomassie blue but showed “negative” staining when gels were stained with silver. Several components (but not the 22-kDa polypeptide) bore phosphocholine epitopes. Apart from the negatively staining bands, most of the 2ME-soluble sheath components were recognized by antibodies of L. carinii -infected Mastomys coucha . Except for several polypeptides that had been unspecifically recognized by IgM, the antibody response to sheath components started at the end of the prepatent period.
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Litomosoides carinii: extraction of the microfilarial sheath components and antigenicity of the sheath fractions.
Parasitology research, 1992Co-Authors: G. Bardehle, H. H. Schott, Stephan Stirm, Dietmar Linder, Martin Hintz, Gereon Schares, Horst ZahnerAbstract:Microfilarial sheaths of Litomosoides carinii were isolated and extracted with 2% sodium dodecyl sulfate (SDS) and 5% 2-mercaptoethanol (2ME). Extraction with SDS alone did not alter the ultrastructure of the sheaths and yielded five polypeptides (27-67 kDa) that were not recognized by antibodies of infected hosts but reacted with antibodies to host-serum proteins. 2ME treatment caused partial solubilization of the sheaths (45% as determined by amino acid analysis), which could be further improved by combining 2ME with SDS. The remainder showed filamentous/threadlike structures on electron microscopic examination. As compared with whole sheaths, the insoluble proportion was markedly enriched in alanine and cysteine but contained less galactosamine, serine, and threonine. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of 2ME/SDS-extractable components showed 12-16 bands of 14- greater than 120 kDa. A predominant component had an apparent molecular mass of 22 kDa. Two bands (42 and 120 kDa) could be stained with Coomassie blue but showed "negative" staining when gels were stained with silver. Several components (but not the 22-kDa polypeptide) bore phosphocholine epitopes. Apart from the negatively staining bands, most of the 2ME-soluble sheath components were recognized by antibodies of L. carinii-infected Mastomys coucha. Except for several polypeptides that had been unspecifically recognized by IgM, the antibody response to sheath components started at the end of the prepatent period.
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A major Litomosoides carinii microfilarial sheath glycoprotein (gp22): amino terminal sequence and immunological studies with corresponding synthetic peptides.
Parasitology, 1991Co-Authors: G. Bardehle, H. H. Schott, Stephan Stirm, Dietmar Linder, Martin Hintz, Franz Josef Conraths, Gereon Schares, F. Fahrenholz, B. Schützle, W. StüberAbstract:The major glycoprotein of the sheath of Litomosoides carinii microfilariae (gp22) was analysed for its amino acid and amino sugar composition. It is rich in proline, glutamine/glutamic acid and glycine and contains (N-acetyl)galactosamine. The N-terminal amino acid sequence was determined up to position 37. It consists of a group of 6 repeats of the pentapeptide sequence methionine-glycine-proline-glutamine-proline with two minor modifications in repeats 3-6, while the first two repeats follow the general pattern more loosely. Identical N-terminal amino acid sequences were found in at least two other sheath polypeptides (33 kDa, 39 kDa). Antisera prepared against 3 overlapping synthetic peptides corresponding to the amino terminus of gp22 recognized different epitopes. They all reacted with identical patterns of sheath polypeptides. The antisera failed to recognize antigens of 4th-stage larvae of L. carinii. In contrast, cross-reacting epitopes were detected in other parasite stages. Antisera reacted with material surrounding embryos and microfilariae in the uterus of females, and caused patchy fluorescence on the sheath of blood-derived and in vitro-released microfilariae.