Glycosphingolipids in cestodes

Abstract

The presence of glycosphingolipids in the metacestodes of the fox tapeworm, Tueniu crassiceps, has been established. The normal-phase TLC pattern of the neutral-fraction glycolipids revealed groups of bands corresponding to homologous components of increasing sugar chain length. The three simplest glycolipid components have been isolated and their chemical constitution determined as being of the neogala series: Galpl Cer, Galp6Galpl Cer and Galp6Galfl6Galbl Cer. The ceramide tetrasaccharide fraction has been found to consist of a mixture of neogalatetraosylceramide, as an elongation of the neogala series, Gal/36Galp6Galp6GalplCer and the component Gala4Galp6-GalB6GalplCer (both occurring in approximately equimolar proportions). The long-chain bases of the ceramide monogalactoside, digalactoside, trigalactoside and tetragalactosides contain, as well as small amounts of sphingosine, predominantly dihydrosphingosine/phytosphingosine in the approximate ratios 1.7: 1, 1.4: 1 , l : 1 and 2.3: 1, respectively. The major ceramide fatty acids have particularly long chains, with hexacosanoic and octacosanoic acids predominating. Upon reverse-phase TLC, the glycolipid components ceramide monogalactoside, digalactoside and trigalactoside were each separable into five component bands. Parent glycolipid components therefore show component band distributions comparable to one another in being governed by similar ceramide constitutions.As a possible reflection of their general relevance in biology, glycolipids are widely distributed in tissues of plants [l, 21, animals [3] An investigation of the glycolipids of multicellular parasites (protozoan parasites do not appear to contain major amounts of classical glycosphingolipids, i.e. compounds containing sugar linked to ceramide) was initiated in this laboratory, with the aim of increasing our knowledge of the diversity and distribution of their glycosphingolipids. It is hoped that this information will contribute to a better understanding of the putative roles of parasite glycosphingolipids in the maintenance of parasite integrity, in the mediation of parasite/ host interactions and in their significance in the host immune response. As a model, the metacestode stage of Taenia crassiceps has been chosen because of its relevance to other parasitic helminths that are pathogenic in humans, as well as for ease of propagation in laboratory mice [12]. Preliminary data have shown their neutral-fraction glycolipids to be antigenic, as evidenced by immunoreactivity (ELISA and HPTLC immunostaining) towards T. crassiceps metacestode-elicited infection serum, and, interestingly, against an affinitycolumn-isolated fraction [with parasite-derived ceramide trihexoside (CTH) as the ligand] [13].The results have shown that T. crassiceps metacestodes contain an array of glycolipids which can be separated by TLC into groups of chromatographic bands corresponding to homologous components of increasing sugar chain length. Isolation of ceramide monosaccharide, disaccharide, trisaccharide and tetrasa...

A Novel Endoglycoceramidase Hydrolyzes Oligogalactosylceramides to Produce Galactooligosaccharides and Ceramides

“…3, A and B). As expected, the enzyme displayed a (␤/␣) 8 barrel structure in which Glu 234 at the end of ␤-strand 4 and Glu 341 at the end of ␤-strand 7 could function as an acid/base catalyst and a nucleophile, respectively. Furthermore, the distance between the two catalytic Glu was separated by 5.8 Å (Fig.…”

“…Eight residues essential for the catalytic reaction in microbial and animal endoglycoceramidases were all conserved in the deduced amino acid sequence of the novel enzyme. Homology modeling of the enzyme using endocellulase E1 as a template revealed that the enzyme displays a (␤/␣) 8 barrel structure in which Glu 234 at the end of ␤-strand 4 and Glu 341 at the end of ␤-strand 7 could function as an acid/base catalyst and a nucleophile, respectively. Site-directed mutagenesis of these glutamates resulted in a complete loss of the activity without a change in their CD spectra.…”

“…(6), and some pathogenic cestode parasites (Echinococcus multilocularis (7), Taenia crassiceps (8), Spirometra erinacei (9), and Metroliasthes cotarunix (10). Recently, it was revealed that aureobasidin A-resistant Zygomycetes species synthesized 6-gala series GSLs (tentatively designated CDS, CTS, CTeS, and CPS) instead of inositol phosphorylceramide (11).…”

A Major Echinococcus multilocularis Antigen Is a Mucin-type Glycoprotein

“…However, Gal repeats appear to be cestode-specific motifs. In glycosphingolipids isolated from the adult stage of Metroliasthes coturnix, metacestodes of Taenia crassiceps and E. multilocularis Gal␤1-4Gal and Gal␤1-6Gal sequences have been demonstrated, and the latter motif was suggested to constitute an epitope recognized by sera from alveolar echinococcosis patients (17)(18)(19). In this context, it would be informative to determine the epitope recognized by the MAbG11 as used in this study for the purification and detection of the Em2(G11) antigen.…”

Incorporation of UDP-Galactose and UDP-GalNAc into midgut tissue of Plutella xylostella (Lepidoptera: Yponomeutidae), which are susceptible and highly resistant to Bacillus thuringiensis Cry1Ac

“…These saccharides were specifically found in flatworms, platheliminthes, such as tapeworm and round worm, and in annelida, such as earthworms (Dennis et al, 1992;Hada et al, 2001). Recently, however, these oligosaccharides were also discovered in zygomycetes such as Rhizopus (Aoki et al, 2004) and thus they are much more widely distributed than had originally been thought.…”