We made a comparative study of the structures of the oligosaccharides on the glycoproteins from Caco-2 human colonic adenocarcinoma cells, before and after differentiation. Enterocytic differentiated Caco-2 cells highly express H type 1 blood group antigen on the cell surface as well as activities of brush border membrane hydrolases, such as dipeptidyl peptidase IV and alkaline phosphatase. A strong correlation was observed between the amounts of H type 1 blood group antigen and the degrees of differentiation. Structural analysis with use of lectin affinity high performance liquid chromatography revealed that typical mucin-type sugar chains of the glycoproteins from undifferentiated cells have H type 2 group, linear polylactosamines, and core 1 structure. On the other hand, differentiated cells newly contain H type 1 and Le b groups and core 2 structure. Mucins with H type 1 group make contact with brush border membrane enzymes on differentiated cells. Furthermore benzyl 2-acetamide-2-deoxy-␣-D-galactopyranoside inhibited both expression of H type 1 group on the cell surface and enhancement of brush border membrane enzyme activities even in the presence of a differentiating inducer. These results suggest that the mucintype sugar chains with H type 1 group have important functions regarding differentiation of Caco-2 cells.Caco-2 cells derived from a human colonic adenocarcinoma differentiate into enterocytes-like cells spontaneously (1) or by induction with sodium butyrate (2). During enterocytic differentiation, in addition to morphological change with acquisition of a brush border, various biological changes have been noted, for example, expression of brush border-associated enzymes (1), mucin synthesis (3), and glycosylation. However, little is known of detailed oligosaccharide structures before and after differentiation of Caco-2 cells. Decrease in polylactosaminoglycans of lysosomal membrane glycoprotein h-Lamp-1 was observed in spontaneously differentiated Caco-2 cells (4), but, unexpectedly, the glycosyltransferases directly involved in polylactosaminoglycan biosynthesis remain essentially unchanged (5). Findings that increased activities of branching enzymes and decreased activity of mucin-type sugar chain core 1 enzyme were also obtained (5). Although these results suggest a change in glycosylation with differentiation of Caco-2 cells, no information on outer chains that contain blood group antigens and interact with other cells has been available. Only an increase in the ␣2,6-sialylation after differentiation has been reported (6). Differentiated Caco-2 cells are used for a model of adherence of bacteria to the intestinal epithelium (7,8). This protein-carbohydrate interaction is critical for bacterial infection and involves microbial lectin-like adhesins and specific oligosaccharides present on the intestinal epithelium. To elucidate oligosaccharide structures on the surface glycoproteins of Caco-2 cells is essential for a better understanding of the mechanism of microbial infections. For this purpose ...

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The fatty acids of three strains of extremely thermophilic bacteria and three strains of moderately thermophilic bacteria were examined by gas liquid chromatography. All the thermophiles contained straight, iso, and ante‐iso branched fatty acids. Iso C17∶0 acid was abundant in both the moderately thermophilic strains (10–33%) and the extremely thermophilic strains (50–61%). The pair of fatty acids iso C15∶0 and iso C17∶0 was the predominant pair in both the moderately (34–64%) and extremely (76–87%) thermophilic strains. The pair of fatty acids ante‐iso C15∶0 and ante‐iso C17∶0 was present in larger amount in moderately (25–34%) than in extremely (8.5–15%) thermophilic strains. No hydroxy cyclopropane, or unsaturated fatty acids were found. One extreme thermophile,Flavobacterium thermophilum HB‐8 was grown at 6 different culture temperatures from 49–82 C, and the changes of its fatty acid composition were studied. The ratios of iso C17∶0/iso C15∶0 and ante‐iso C17∶0/ante‐iso C15∶0 were much greater at higher culture temperatures, indicating chain elongation.

The Sda blood group carbohydrate structure, GalNAcbeta1-4[NeuAcalpha2-3]Galbeta1-4GlcNAc-R, is expressed on glycolipid and glycoprotein in human gastrointestinal mucosa. The expression of the Sda determinant dramatically decreases in cancer tissue. The activity of the beta1,4N-acetylgalactosaminyltransferase (Sda-GalNAcT), which transfers GalNAc to NeuAcalpha2-3Galbeta1-4Glc(NAc)-R, correlates with the expression of the Sda immuno-epitope. From the total RNA fraction of human gastric mucosa, we have amplified a cDNA segment by reverse-transcription-polymerase-chain reaction (RT-PCR), using primers designed according to the cDNA sequence of a murine beta1,4GalNAcT which synthesizes the Sda determinant. An RT-PCR product of 390 bp shared 85% nucleotide identity with the murine Sda-related beta1,4GalNAcT. This RT-PCR product hybridized to a transcript in mRNA prepared from human gastric mucosa. In RT-PCR using specific primers to this PCR product, Sda-GalNAcT mRNA was detected in all samples of normal stomach and small intestine examined and the majority of normal colonic specimens. Six out of nine cases of gastric cancer, and 9 out of 13 cases of colonic cancer failed to produce the target DNA. These results correlate with the beta1,4GalNAcT activity measured in the same samples. In conclusion, a segment of the cDNA for betal,4GalNAcT which determines expression of the Sda carbohydrate structure was obtained, and reduced transcription of this beta 1,4GalNAcT resulted in the disappearance of the Sda epitope in gastrointestinal cancer.