| 1 | Author
| H. Erm, Ann Bothe, Gislene Barbosa, JohannaD. | Requires cookie* | | Title
| Nitrogen Fixation and Nitrate Respiration by A zospirillum brasilense  | | | Abstract
| Azospirillum The 0 2-sensitivitiy of N 2-fixation by the carotenoid forming strain Azospirillum brasilense Cd and the colourless strain Sp 7 is com pared in the present communication. As no difference in the reaction is observed with both strains, it is concluded that carotenoids do not protect nitrogenase from damage by 0 2. Azospirillum spp. have also been shown to perform N O '-dependent ^ -f i x ation. The physiological properties of this reaction are described in more detail in the present communication. Evidence is presented that NO^-dependent N 2-fixation is a transitory reaction, proceeding only as long as the enzymes o f assimilatory nitrate reduction are synthesized by the cells. | | |
Reference
| Z. Naturforsch. 38c, 571—577 (1983); received March 31 1983 | | |
Published
| 1983 | | |
Keywords
| Nitrogen Fixation, N itrate Respiration, Denitrification, Nitrogenase Protection, Carotenoids | | |
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| default:Reihe_C/38/ZNC-1983-38c-0571.pdf | | | Identifier
| ZNC-1983-38c-0571 | | | Volume
| 38 | |
2 | Author
| Karin Kloos, UrsulaM. Hiisgen, Hermann Bothe | Requires cookie* | | Title
| DNA-Probing for Genes Coding for Denitrification, N2-Fixation and Nitrification in Bacteria Isolated from Different Soils  | | | Abstract
| Bacteria isolated from different layers of four soils of the Cologne area were analyzed for denitrifying, nitrifying and N2-fixing isolates by colony hybridization using gene probes. In the soils tested, the percentage of denitrifying bacteria among the total population isolated was 3 -8 % (in one case exceptionally 15%) and thus small. Denitrifying bacteria were partic ularly enriched in the upper layer (depth ~ 5 cm) and were present only in low amounts at 25 cm depth in two gleysol soils. Nitrate apparently did not determine the distribution of denitrifying bacteria in these soils. The potential denitrification activity of different soil layers coincided with the distribution pattern of isolates assessed by DNA-probing. The total number of bacteria and of denitrifying isolates was considerably higher in or at the roots of plants than in the bulk, root-free soil adjacent to the plants. The percentage of the isolated aerobic N2-fixing bacteria varied between 0 -3 % , and these bacteria could be isolated mainly from the upper 5 cm layer. A small portion of the isolates hybridized with the probe coding for part of one subunit of ammonia monooxygenase from Nitrosomonas europaea. The inves tigation showed that DNA-probing can provide useful information about the relative distri bution of denitrifying and N2-fixing bacteria in different soils and their layers. | | |
Reference
| Z. Naturforsch. 53c, 69—8 (1998); received October 14/November 6 1997 | | |
Published
| 1998 | | |
Keywords
| DNA-Probing, Colony Hybridizations, Soil Ecology, Denitrification, Nitrification, Nitrogen Fixation | | |
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| default:Reihe_C/53/ZNC-1998-53c-0069.pdf | | | Identifier
| ZNC-1998-53c-0069 | | | Volume
| 53 | |
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