Publications by authors named "Asmaa El Hamidi"

Endotoxin is recognized as one of the virulence factors of the Bordetella avium bird pathogen, and characterization of its structure and corresponding genomic features are important for an understanding of its role in pathogenicity and for an improved general knowledge of Bordetella spp virulence factors. The structure of the biologically active part of B. avium LPS, lipid A, is described and compared to those of another bird pathogen, opportunistic in humans, Bordetella hinzii, and to that of Bordetella trematum, a human pathogen.

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Bordetella parapertussis like B. pertussis, is a causal agent of whooping cough but is not a strictly human pathogen. Because its endotoxin, a major structural component of the Gram-negative outer membrane, is an important virulence factor, we have analyzed the structure of its toxic lipid domain, in one rough and two smooth bacterial strains.

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Endotoxins [lipopolysaccharides (LPSs)] are part of the outer cell membrane of Gram-negative bacteria. Their biological activities are associated mainly with the lipid component (lipid A) and even more specifically with discrete aspects of their fine structure. The need for a rapid and small-scale analysis of lipid A motivated us to develop a procedure that combines direct isolation of lipids A from bacterial cells with sequential release of their ester-linked fatty acids by a mild alkali treatment followed by MALDI-MS analysis.

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Endotoxins (lipopolysaccharides) are the main components of Gram-negative bacterial outer membranes. A quick and simple way to isolate their lipid region (lipid A) directly from whole bacterial cells was devised. This method using hot ammonium-isobutyrate solvent was applied to small quantities of cells and proved to be indispensable when a rapid characterization of lipid A structure by mass spectrometry was required.

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