INVESTIGADORES
BIANCO Maria Isabel
congresos y reuniones científicas
Título:
EFFECT OF GRAPEFRUIT LEAVES EXTRACT IN XANTHAN STRUCTURE AND COMPOSITION
Autor/es:
PABLO M. YARYURA; VALERIA P. CONFORTE; M. ISABEL BIANCO; CECILIA RODRIGUEZ; EDUARDO PRIETO; PATRICIA L. SCHILARDI ; ADRIÁN A. VOJNOV
Lugar:
Ciudad de Buenos Aires
Reunión:
Congreso; Reunión Conjunta de Sociedades de BioCiencias; 2017
Institución organizadora:
Sociedades de BioCiencias
Resumen:
Xanthomonas citri subsp. citri (Xcc) is the causal agent of citruscanker, a disease that affects different species of citrus. Xcc, aswell as other Xanthomonas spp., produces xanthan, a polyanionicexopolysaccharide (EPS), composed by a cellulose backbone witha side chain containing a glucuronic acid residue linked to a mannosethat connects to the backbone and a second terminal mannose.Mannose residues can be substituted by nonglycosidic groups (acetylor pyruvate). Xanthan is an important virulence factor that affectsbacterial growth in planta and biofilm formation. We previously demonstratedan association between xanthan structure/compositionand its role as virulence factor. Considering this background, weaimed to analyze whether xanthan structure/composition changedin presence of citrus leaf extract. For this work, we cultured Xccin grapefruit leaves aqueous extract (GLE). First, we observed thatXcc grew better in GLE than in peptone-yeast extract-malt extractmedium (PYM). Xanthan synthetized by Xcc growing in GLE (Xan-GLE) showed different macroscopic qualities compared to xanthanproduced by Xcc growing in PYM (Xan-PYM). Using scanning electronicmicroscopy, we observed that Xan-GLE presented a moreheterogenous and disordered structure than Xan-PYM. The atomicforce microscopy analysis revealed Xan-PYM molecules as longstrands or double strands, while Xan-GLE molecules appeared tobe shorter than the Xan-PYM ones and with a different arrangement(looking like spiders). On the other hand, analytical determinationsreveled that Xan-GLE has higher content of pyruvate groups thanXan-PYM. These results could explain the behavior of the xanthanmolecules in presence of GLE. A greater number of pyruvate groupscauses an increase in intramolecular electrostatic repulsions betweennegative charges of xanthan molecules, affecting the abilityof this EPS to hydrate and to interact with other molecules in themedia.