pLipid A fractions from iPseudomonas aeruginosa/i and iPseudomonas alcaligenes/i have similar compositions and structural features. By means of hydrazinolysis of the parent lipopolysaccharides and partial hydrolysis of the deacylation products, it was established that both lipids are derived from the β-(1→6)-linked disaccharide of glucosamine. Phosphorylated derivatives of the disaccharide from iPs. aeruginosa/i were also characterized. The lipids differ mainly in the absence of hexadecanoic acid and 2-hydroxydodecanoic acid from the lipid from iPs. alcaligenes/i. Evidence that in iPs. aeruginosa/i these acids are ester-linked to residues of 3-hydroxyalkanoic acids (including 3-hydroxydecanoic acid) was obtained. Heterogeneity of lipid A fractions was indicated by t.l.c., and by gel filtration of de-iO/i-acylation products from mild alkaline methanolysis of the lipids./p
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