Background
Bronchial infection by microorganisms, particularly
Pseudomonas aeruginosa, is apparently responsible for
the morbidity and mortality of victims of cystic fibrosis
(CF). Al Awqati and co-workers have found that CF
bronchial and pancreatic epithelia reversibly bind the
microorganism P. aeruginosa.
forward to suggest that asialo GM1 (2a, see Figure 1),
which is bound through a hydrophobic attraction to the
apical membrane of CF epithelia, is a likely binding site
for P. aeruginosa and that its increased abundance
contributes to bronchial bacterial invasion (Figure 1).
These findings stimulate interest in evaluating glyco-
sides of the type 2b where the core carbohydrate is
retained, but the ceramide attachment is replaced by
simple glycosidic linkages. The synthetic carbohydrate
ligands in suitably bioavailable form could serve as
“decoys” to prevent or clear up bacterial infection. The
understanding of how glycolipid “ligands” interact with
protein receptors in infectious bacteria could well benefit
from an insight as to structure-activity relationships
(SAR) of the carbohydrate domain. Efforts toward that
goal have already led to a stereoselective synthetic route
to asialo GM1 and other simpler glycosides.3 For a
thorough investigation of whether these asialoglycosides
can function as potential antagonists of bacterial invasion
in keeping with the findings of Tuomanen,4 Al Awqati,1
and Krivan,5 one needed access to sialylated
mimicking GM1 for the case at hand.
1,2 Strong evidence was put