INVESTIGADORES
COUTO Alicia Susana
congresos y reuniones científicas
Título:
Studies on the lipid structure of Brucella suis and Brucella abortus lipopolysaccharide
Autor/es:
A.C. CASABUONO ; C. CZIBENER; M. G. DEL GIUDICE,; E. VALGUARNERA,; J. E. UGALDE; A. S. COUTO
Lugar:
Buenos Aires
Reunión:
Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017
Institución organizadora:
Sociedades de Biociencias
Resumen:
Brucellae are Gram-negative bacteria that cause brucellosis, one of the most worldwide distributed zoonosis, transmitted to humans by contact with either infected animals or their products. The lipopolysaccharide (LPS) exposed on the cell surface is considered a major virulence factor of Brucella, and it induces a strong antibody response during infection when whole cell vaccines are used. LPSs present three regions with different chemical and biological properties: the lipid A, the core oligosaccharide and the O-antigen. In the last years although some studies go deeper into the structures of the core and the O-antigen of these LPS, no analysis of the lipid A has been performed. In this context, we have analyzed in depth the structure of the lipid A isolated from Brucella suis and Brucella abortus LPSs. The lipid A moieties were released by acid hydrolysis from both LPS and analyzed by MALDI-TOF mass spectrometry in the positive and negative ion modes, using different matrices. Interestingly, a new feature was detected: the presence of a pyrophosphorylethanolamine residue (PPEtN) substituting the backbone. LID-MS/MS analysis of some of the detected ions allowed to assure a Lipid A structure composed by a diGlcN3N disaccharide, mainly hexa-acylated and penta-acylated, bearing one phosphate and one PPEtN residue. As one mechanism of antimicrobial peptide resistance is to modify the cell surface with positively charged moieties, the finding that B. abortus and B. suis contain one PPEtN on their lipid A moieties may open new possibilities for exploring into the not fully elucidated set of mechanisms involved in Brucellae virulence that include the ability to escape prompt detection by innate immunity during the initial stages of infection.
