{"title":"Nitrogenase activity and inactivation in isolated bacteroids from the legume siratro and the non-legume Parasponia rigida","authors":"Ruth A. Sandeman , Peter M. Gresshoff","doi":"10.1016/0304-4211(85)90004-5","DOIUrl":null,"url":null,"abstract":"<div><p>We demonstrate continued nitrogenase activity in isolated bacteroids of <em>Rhizobium</em> strain ANU289 from nodules of siratro (<em>Macroptilium atropurpureum</em>) and the non-legume <em>Parasponia rigida</em> for periods up to 240 min with maximum activities maintained at 52 nmol ethylene produced h<sup>−1</sup> mg<sup>−1</sup> protein. Both legume and non-legume bacteroids showed a broader oxygen tolerance in the presence of the nodule supernatant. Isolated <em>Parasponia</em>-derived bacteroids exhibited an optimum nitrogenase activity at about 0.1% O<sub>2</sub> in the gas phase, while siratro bacteroids had a slightly higher O<sub>2</sub> optimum. These findings illustrate that (i) <em>Rhizobium</em> bacteroids isolated from a non-legume host are highly oxygen-sensitive for their nitrogenase activity, (ii) the <em>Parasponia</em> nodule supernatant increases the oxygen tolerance of the bacteroids.</p></div>","PeriodicalId":20221,"journal":{"name":"Plant Science Letters","volume":"37 3","pages":"Pages 199-204"},"PeriodicalIF":0.0000,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-4211(85)90004-5","citationCount":"8","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Plant Science Letters","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0304421185900045","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 8
Abstract
We demonstrate continued nitrogenase activity in isolated bacteroids of Rhizobium strain ANU289 from nodules of siratro (Macroptilium atropurpureum) and the non-legume Parasponia rigida for periods up to 240 min with maximum activities maintained at 52 nmol ethylene produced h−1 mg−1 protein. Both legume and non-legume bacteroids showed a broader oxygen tolerance in the presence of the nodule supernatant. Isolated Parasponia-derived bacteroids exhibited an optimum nitrogenase activity at about 0.1% O2 in the gas phase, while siratro bacteroids had a slightly higher O2 optimum. These findings illustrate that (i) Rhizobium bacteroids isolated from a non-legume host are highly oxygen-sensitive for their nitrogenase activity, (ii) the Parasponia nodule supernatant increases the oxygen tolerance of the bacteroids.
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