Pseudomonas saccharophila could fix N$ sb2$ under micro-aerobic conditions, heterotrophically and chemolithotrophically. Uptake hydrogenase activity under heterotrophic conditions had no effect on the O$ sb2$ sensitivity of nitrogenase. H$ sb2$ induced whereas sucrose and O$ sb2$ repressed hydrogenase synthesis. Sucrose and O$ sb2$ did not inhibit hydrogenase activity. Hydrogenase and urease were located in the membrane and soluble fractions, respectively. Nickel stimulated growth, hydrogenase expression, and nitrogenase activity under N-limited chemolithotrophic conditions. Hydrogenase synthesis specifically required nickel and its repression by O$ sb2$ was alleviated by increasing the nickel concentration. Incorporated $ sp{63}$Ni$ sp{2+}$ was about 3 times higher in the soluble than in the membrane fraction. The short-term uptake of nickel was energy-independent and had an apparent $K sb{m}$ of 31.7 uM and $V sb{max}$ of 3.8 nmol Ni$ sp{2+}$ (mg protein)$ sp{-1}$min$ sp{-1}$. / A counting method for heterotrophic and chemolithotrophic N$ sb2$-fixing H$ sb2$-oxidizing bacteria was developed. The white bean rhizosphere soil showed relatively high numbers of these bacteria.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.74290 |
| Date | January 1989 |
| Creators | Barraquio, Wilfredo L. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Microbiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001069663, proquestno: AAINN63521, Theses scanned by UMI/ProQuest. |
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