IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
PlyB is a polarly located glycanase that cleaves the chains of EPS and has a profound impact in the matrix of the rhizobial biofilm
Autor/es:
ABDIAN, P; ALONSO, D; VON BILDERLING C.; RUSSO, D. M.; PIETRASANTA, LI; ZORREGUIETA, A
Lugar:
Buenos Aires
Reunión:
Congreso; GlycoAR 2014, First International Symposium on Glycobiology; 2014
Institución organizadora:
xx
Resumen:
Rhizobium leguminosarum
are soil bacteria involved in the fixation of atmospheric nitrogen in symbiosis
with leguminous plants. These bacteria may adopt different lifestyles, growing
on soil particles, on root hairs or within legume roots. During this complex
life cycle R. leguminosarum forms
biofilms, communities of microorganisms that live encased in a self-produced polymeric
matrix. We study the biofilm formed by R.
leguminosarum under laboratory conditions, that may reflect its survival strategy in the
rhizosphere. The main component of the biofilm matrix is an acidic
exopolysaccharide (EPS), composed of Glc, Gal and GlcA in a 5:2:1 ratio,
substituted with non-carbohydrate residues. The length of EPS molecules is
regulated during its biosynthesis and also by the activity of extracellular
glycanases. These glycanases are secreted by a type I PrsDE secretion system
and have been shown to be active only on the surface of EPS producing cells. We
have previously observed that PlyB is polarly located and that a plyB mutant is affected in biofilm
formation. Here, we compare strains with different levels of expression of PlyB
and analyze by gel filtration and atomic force miscroscopy (AFM) the
distribution of EPS molecules length, showing that PlyB activity is essential
for the production of an EPS with a normal length distribution and biofilm
formation.