The interaction of Vatairea macrocarca and Rhizobium tropici: net H^+ efflux stimulus and alteration of extracellular Na^+ concentration
We studied the effect of a lectin isolated from seeds of the legume Vatairea macrocarpa on net H^+ efflux in Rhizobium tropici, a bacterium capable of nodulating legume Phaseolus vulgaris. V. macrocarpa lectin (VML) was observed to temporarily stimulate the specific net H^+ efflux in R. tropici. When VML was present at 32 @mgml^-^1, with or without 2 @mM galactose (Gal), a specific net efflux >2.4 pM H^+(min)^-^1 mg dry biomass^-^1 was induced. There was no detectable net H^+ efflux when bovine serum albumin (16 @mgml^-^1) was tested. Addition of 16 @mgVMLml^-^1 resulted in a 700% increase of the extracellular Na^+ concentration. The soluble proteins in the supernatant containing VML extract indicate a maximum immobilization of +/-10 @mgVMLml^-^1, with a minimum of 36,600 dimers or 8500 larger aggregates of VML binding in each bacterium. Our data suggest that VML activates Rhizobium as a bioenergetic substrate molecule, resulting in potential alterations of the external bacterial membrane.
Copyright © 2004 Elsevier Ltd. All rights reserved.
Version: za2963e q8za4 q8zb9 q8zcd q8zdd q8ze3 q8zf9 q8zg0