The Isolation and Characterization of Lipopolysaccharide-defective Mutants of Pseudomonas aeruginosa PAC1

Publisher Website
Google Scholar
Abstract
Mutants with defective lipopolysaccharides (LPS) were isolated from P. aeruginosa PAC1R (Habs serogroup 3) by selection for resistance to aeruginocin from P. aeruginosa P16. Carbenicillin-sensitive mutants were isolated from P. aeruginosa PAC1, but not all had defective LPS. Rough colonial morphology and resistance to bacteriophage 119X appeared to be independent of LPS composition. The LPS from 5 mutants were analyzed and compared with that of the parent strain. Separation of partially-degraded polysaccharides from LPS from PAC1 on Sephadex G75 yielded 2 different high MW fractions and a phosphorylated low MW fraction (L). The mutant LPS lacked most or all of the high MW fractions but retained some low MW material. That from PAC1 and 2 of the mutants was separated by elution from Biogel P6 into 2 fractions. One, L2, was the core polysaccharide, while the other, L1, contained short antigenic side-chains attached to the core like the semi-rough (SR) LPS of the Enterobacteriaceae. The 2 mutants which gave the L1 fraction reacted with Habs 3 and PAC1 antisera as did the parent strain. The other 3 mutants were unreactive, and their LPS contained core components only. One appeared to have a complete core, while the other 2 lacked rhamnose and rhamnose plus glucose, respectively. Thus there may be 4 types of LPS in PAC1: one contains unsubstituted core polysaccharide and yields L2 on acid hydrolysis, another has short antigenic side-chains of the SR type and yields the L1 fraction, while the 2 high MW fractions are derived from core polysaccharides with different side-chains.