Tyvelose preparation

Fig. 6.2. Caco-2 epithelial cell monolayers cultured with T. spiralis L1 larvae in (A) the absence or (B) presence of 1 mg ml 1 rat monoclonal, tyvelose-specific antibody 9D4 (McVay etal., 2000). Monolayers were fixed and stained with trypan blue as described in ManWarren etal. (1997). (A) Serpentine trails of nuclei in dead cells are evident, revealing the paths travelled by larvae. (B) Tyvelose-specific antibody has inhibited the migration of the larva such that it is encumbered in cell debris and has pulled up a large area of the monolayer, creating a plaque (P). Bar = 50 urn. Photomicrograph prepared by C. McVay, TTUHSC, Lubbock, Texas. 

The derivative (9) of 3,6-dideoxy-a-D-xyIo-hexopyranose (abequose) was isolated from a strain of Salmonella typhimurium,16 that (10) of 3,6-dideoxy-a-D-nfco-hexopyranose (paratose) from Salmonella paratyphi,54 and a mixture of 10 and the ester (11) of 3,6-dideoxy-a-D-arabino-hexopyranose (tyvelose) from Salmonella enteritidis.,6 It was shown that these derivatives are formed from cytidine 5 -(a-D-glu-copyranosyl pyrophosphate) by treatment with nicotinamide adenine dinucleotide (NAD+) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) in the presence of cell extracts of the respective bacterial strain. For example, formation of 9 is characteristic of preparations from Salmonella, group B,55,56 or Pasteurella pseudotuberculosis, type II.56 The derivative 10 was obtained with extracts of Salmonella, group A,56 and Pasteurella pseudotuberculosis, type I and III,56 and a mixture of 10 and 11 with those of Salmonella, group D,55-60 or Pasteurella pseudotuberculosis, type IV 56.59,60 Under similar conditions, the ester (12) of cytidine 5 -pyro-... 

The disaccharide epitope a-Tyv-(l —>3)-a-o- Man present in the D1 Salmonella serotype was synthesized as the pentenyl glycoside. The tyvelose donor 138 was prepared from ethyl l-thio-p-o-mannopyranoside 137 employing a single dideoxygenation step (Scheme 40). Glycosylation of 138 with the mannopyranosyl... 

Some of the rare sugars that have been prepared by way of chloro-deoxy derivatives are 4,6-dideoxy-3-0-methyl-D-xyZo-hexose (D-chal-cose), 3,6-dideoxy-D-n foo-hexose (paratose), 3,6-dideoxy-D-arafcmo-hexose (tyvelose), methyl 2,3-dideoxy-/3-D-glr/cero-hex-2-enopyrano-sid-4-ulose, and certain aminodeoxy sugars. 

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