| 1. |
- Bouhours, Danièle, et al.
(författare)
-
Structure and genetic polymorphism of blood group A-active glycosphingolipids of the rat large intestine.
- 1995
-
Ingår i: Biochimica et biophysica acta. - 0006-3002. ; 1255:2, s. 131-40
-
Tidskriftsartikel (refereegranskat)abstract
- Study of blood group A- and B-active glycosphingolipid content of the epithelium of the large intestine of 16 strains of inbred rats led to the discovery of two related strains, SHR and WKY, devoid of A-active glycolipids, whereas all strains expressed B-active glycolipids. This finding evidenced a new A/non-A genetic polymorphism in the rat. Blood group A-active glycolipids were isolated from the large intestine of F344 rats and purified by affinity chromatography on immobilized Helix pomatia lectin. Three glycolipid fractions were separated by preparative thin-layer chromatography and characterized by electron-impact mass spectrometry of their permethylated and permethylated-LiAlH4-reduced derivatives. They were identified as a tetraglycosylceramide (A-4), a hexaglycosylceramide (A-6), and a difucosylated heptaglycosylceramide (A-7) with small amounts of monofucosylated octaglycosylceramide (A-8). Methylation analysis and fragmentation indicated that A6 and A-8 had a lacto- and A-7 a neolactotetraosylceramide core, respectively, identical to the core structures of B-6 and B-7 previously characterized in the large intestine of WF rats (Angström et al. (1987) Biochim. Biophys. Acta 926, 79-86). Upon methylation analysis, B-6 and B-7 purified from SHR (A-deficient) and F344 (A-expressing) were found identical to those of WF rats. This result indicated that precursor substrates for the synthesis of A-active glycolipids were available in SHR rats and thus the genetic deficiency of A-active glycolipid expression probably originated in a defect of the termination of the blood group A determinant by the alpha-3-N-acetylgalactosaminyltransferase.
|
|
| 2. |
- Olson, Fredrik J., 1975, et al.
(författare)
-
Blood group A glycosyltransferase occurring as alleles with high sequence difference is transiently induced during a Nippostrongylus brasiliensis parasite infection.
- 2002
-
Ingår i: The Journal of biological chemistry. - 0021-9258. ; 277:17, s. 15044-52
-
Tidskriftsartikel (refereegranskat)abstract
- Neutral mucin oligosaccharides from the small intestine of control rats and rats infected with the parasite Nippostrongylus brasiliensis were released and analyzed by gas chromatography-mass spectrometry. Infected animals expressed seven blood group A-like structures that were all absent in the control animals. The blood group A nature of these epitopes was confirmed by blood group A reactivity of the prepared mucins, of which Muc2 was one. Transferase assays and Northern blotting on small intestines from infected animals showed that an alpha-N-acetylgalactosaminyltransferase similar to the human blood group A glycosyltransferase had been induced. The expression was a transient event, with a maximum at day 6 of the 13-day-long infection. The rat blood group A glycosyltransferase was cloned, revealing two forms with an amino acid similarity of 95%. Both types had blood group A transferase activity and were probably allelic because none of 12 analyzed inbred strains carried both types. The second type was found in outbred rats and in one inbred strain. First generation offspring of inbred rats of each type were heterozygous, further supporting the allelic hypothesis. The transient induction and the large allelic variation could suggest that glycosyltransferases are part of a dynamic system altering mucins and other glycoconjugates as a protecting mechanism against microbial challenges.
|
|
