INVESTIGADORES
CASTELLI maria Eugenia
congresos y reuniones científicas
Título:
IDENTIFICATION AND CHARACTERIZATION OF A NOVEL EXTRACELLULAR PHOSPHOLIPASE PRESENT IN CLINICAL ISOLATES OF Enterobacter aerogenes
Autor/es:
FEDRIGO, GRISELDA V.; CLEMENTÍN, ANA; CASTELLI, MARÍA E. AND GARCÍA VÉSCOVI, ELEONORA
Lugar:
Pinamar
Reunión:
Congreso; XLI Reunión anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2005
Institución organizadora:
Sociedad Argentina de Investigación en Bioquímica y Biología Molecular
Resumen:
Enterobacter is an opportunistic pathogen associated to nosocomial infections, with increasing incidence in patients from intensive care units. Clinical isolates were phenotypically characterized and we selected an E. aerogenes strain that exhibited extra-cellular phospholipase activity. This activity was absent in strains from normal flora, suggesting that it might be a virulence factor. By phenotypic screening of a sub-genomic library we found a gene enconding for lipase activity. Sequence analysis revealed high homology to phospholipase A1 enconding genes, found only in Serratia, Yersinia, Xanthomonas and Photorhabdus (E. aerogenes has no available genome database). In parallel, by mini Tn5-random mutagenesis, we selected six phenotypically lipase null strains. Strikingly, analysis of the adjacent sequences to the insertion revealed homology to the wecD, wecE, wecF and waaF which are involved in the outer membrane glycolipid (ECA) and LPS biosynthesis. These mutants were not globally affected in the expression of exoproteins, suggesting that wec cluster and waaF gene products could be implicated in the expression, folding or secretion mechanism of the phospholipase.