This may or may not be of interest to you but are you aware of the
occurence of bacterial capsular polysaccharide polysialylation?
Usually attached to membrane proteins (in particular a 20 kDa protein)
found in E coli K1 (poly-sialyl a2,6 linked, both 7 and 9 0 acetyl), E
coli K92 (Alternating a2,8 and a2,9 linked poly-sialyl), Neisseria
meningitidis group B and Neisseria meningitidis group C ( both
polysialyl a2,8), Pasteurella haemolytica A2 (polysialyl a2,8) and
Moraxella nonliquefaciens (polysialy a2,8). see Glycobiology 2(1), pp 5
- 23 1992.
These are human pathogenic strains and not those used for E.coli
recombinant work however.
There are almost certainly other more interesting types to be found,
such as those mentioned by Iain.
martin at axford.demon.co.uk