The interaction of Vatairea macrocarca and Rhizobium tropici: net H⁺ efflux stimulus and alteration of extracellular Na⁺ concentration

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• 作者：Mart??nez ; Cosme R. ; Chanway ; Christopher P. ; Albertini ; Alessandro V.P. ; Figueiredo ; M??rcia V.B. ; et. al.
• 关键词：Ion transport ; Rhizobium ; Lectin ; Vatairea macrocarpa
• 刊名：FEMS Microbiology Letters
• 出版年：2004
• 出版时间：September 1, 2004
• 年：2004
• 卷：238
• 期：1
• 页码：17-22
• 全文大小：453 K

文摘

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 ??gml^???1, with or without 2 ??M 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 ??gml^???1) was tested. Addition of 16 ??gVMLml^???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 ??gVMLml^???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.