title: Production of extracellular biopolymers and identification of intracellular proteins and Rhizobium tropici.
abstract: The objective of this study was to identify species of rhizobia (from the IPA 403 and IPA 49 isolates), to assess the physico-chemical characteristics of the biopolymers produced by these rhizobia and to determine the soluble intracellular proteins that are present in these rhizobia. The polysaccharides containing acetyl and pyruvic acid groups that were produced by different strains that had been cultivated in yeast extract mannitol (YEM) medium for 132, 144, and 168 h were evaluated for yield, viscosity, and concentration. Based on the analysis of their partial 16S rDNA sequences, both isolates were identified as Rhizobium tropici. The polymers produced in liquid YEM medium were recovered, dried and weighed to determine culture yield. Soluble intracellular proteins were identified through the techniques of 2D-PAGE and mass spectrometry for cultures that were cultivated for 168 h. The largest biopolymer yield and the highest viscosity and concentration of acetyl and pyruvic acids were obtained from the IPA 403 isolate after 168 h of culture. The proteins that were identified for the CIAT 899 isolate included elongation factor TU, a chaperone; GroE/GroEs and a putative glycosyltransferase, all of which catalyze the production of polysaccharides. For the IPA 403 strain, dinitrogenase and nitrogenase iron proteins were found. In the IPA 49 strain, glyceraldehyde-3-phosphate dehydrogenase was found along with two other proteins, the beta subunit of an electron-transferring flavoprotein and a dehydrogenase.
authors.affiliation: Laboratory of Soil Biology, Agronomy Institute of Pernambuco (IPA), Av. Gal San Martin, 1371, Bonji, Recife, PE, Brazil. jose.paula@ipa.br
authors.forename: José
authors.initials: J
authors.lastname: Oliveira
authors.forename: Marcia
authors.initials: M
authors.lastname: Figueiredo
authors.forename: Marcia
authors.initials: M
authors.lastname: Silva
authors.forename: Marília
authors.initials: M
authors.lastname: Malta
authors.forename: Claire
authors.initials: C
authors.lastname: Vendruscolo
authors.forename: Hélio
authors.initials: H
authors.lastname: Almeida
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001704:Biopolymers / Q000096:biosynthesis* / Q000737:chemistry*; D003470:Culture Media; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004275:DNA, Ribosomal / Q000032:analysis / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D013058:Mass Spectrometry / Q000379:methods; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D042162:Rhizobium tropici / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014783:Viscosity
chemical_list: D001426:Bacterial Proteins; D001704:Biopolymers; D003470:Culture Media; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S