1. Comparision of lipid A moieties obtained from Bordetella bronchiseptica LPS core mutants.

CASABUONO, ADRIANA; SISTI, FEDERICO; HOZBOR, DANIELA; COUTO ALICIA

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012

Bordetella bronchiseptica can infect a variety of mammals including humans. Defective mutants of the lipopolysaccharide(LPS) structure are used to understand their role in bacteria?hostinteraction. On a 9.73 background, three mutants weregenerated: LP39, defective in the expression of genewhich codes for a heptosyltransferase of the core region; 3394,defective in a gene involved in core substitution with a GalNAc and3398, defective in the glucose transfer to the first heptose of thecore. In this work the LipidAmoieties were released from the LPSmutants, analyzed by mass spectrometry and compared with thewild type strain. It was interesting to note that while the wild typestrain presents a hexa-acylated diglucosamine backbonesubstituted with a phosphoglucosamine unit, lipidAfrom LP39presented a pyrophosphate group. On the other hand, Lipid Aobtained from 3394 mutant showed a hexa-acylated backbonecarrying two phosphoglucosamine units. However, 3398 mutantshowed a hexa-acylated backbone modified withphosphoethanolamine and pyrophosphorylethanolamine groups.How inactivation of genes involved in the core biosynthesis affectsLipid A structures is not clear. However these modifications areknown to alter LPS toxicity as well as vary the charge of Lipid Ainvolved in protection of the bacteria.