Competitive growth of slow growingRhizobium japonicum against fast growingEnterobacter andPseudomonas species at low concentrations of succinate and other substrates in dialysis culture |
| |
Authors: | Claudia Humbeck Heidemarie Thierfelder Peter M Gresshoff Dietrich Werner |
| |
Institution: | (1) Fachbereich Biologie, Philipps-Universität Marburg, Karl v. Frisch-Str., D-3550 Marburg, Federal Republic of Germany;(2) Department of Botany, Australian National University (ANU), Canberra, ACT, Australia |
| |
Abstract: | A cultivation system with simultaneous growth of six bacterial cultures in separate bags in dialysis culture was developed. In a medium with no added carbon source (one half concentrated Hoagland solution, water deionized and distilled), cell number ofRhizobium japonicum increased during a 7 day period by a factor of 35, whereas the number ofEnterobacter aerogenes cells decreased to one half. With a concentration of 100 nM succinate as an additional carbon source in the inflow,Rhizobium japonicum 61-A-101 cell number increased by a factor of 50 during an 8 day period, whereas cell number ofEnterobacter cloacae NCTC 10005 only doubled and ofEnterobacter aerogenes NCTC 10006 decreased. At 10 mM concentration of succinate in the inflow, doubling time the twoEnterobacter strains was about 12 h, compared to about 24 h for theRhizobium japonicum strain. Varying the succinate concentration from 10 mM to 100 nM in the inflow,Rhizobium japonicum 61-A-101 surpassed theEnterobacter aerogenes strains in the growth rate between 1 mM and 100 M succinate in the inflowing medium. Three otherRhizobium japonicum strains (fix+ and fix-) did grow with a similar rate as strain 61-A-101 at very low concentrations of substrate. Growth rates for the strains were confirmed by protein data per culture. Growing in competition with twoPseudomonas strains,Rhizobium japonicum RH 31 Marburg (fix-) did overgrow alsoPseudomonas fluorescens, was however outgrown byPseudomonas putida. In utilizing low concentrations of a14C labelled organic acid (malonate), three strains ofRhizobium japonicum left 2–4 times smaller amounts of14C in the medium than two species ofPseudomonas and two species ofArthrobacter.On sabbatical leave at ANU |
| |
Keywords: | Dialysis culture Enterobacter Growth rates Pseudomonas Rhizobium japonicum |
本文献已被 SpringerLink 等数据库收录! |
|