| | 1 | Author
| D. W. Erner, R. Stripf | Requires cookie* | | | Title
| Differentiation of Rhizobium japonicum, I. Enzymatic Comparison of Nitrogenase Repressed and Derepressed Free Living Cells and of Bacteroids  | | | | Abstract
| Derepressed free living cells of Rhizobium japonicum strain 61-A-101 with leucine as single nitrogen source develop a maximum nitrogenase activity of 180 nmol C2H4-mg protein-1 -h _1 in liquid culture under 2% 0 2 in the gas phase. Only \0% of this activity is found with no oxygen in the gas phase during a 90 min incubation period. The maximum activity under 2% oxygen in the gas phase is unaffected by addition of 1 —100 m M NH4+ and by addition of low concentrations of glutamine (0.36 —1.44 m M) . Specific activities of alanine dehydrogenase (E.C. 1.4.1.1.) aspartate aminotransferase (E.C. 2.6.1.1.) and, with much lower activities, of GOGAT (E.C. 1.4.1.13) in nitrogenase active free living cells are more similar to bacteroids than to nitrogenase repressed free living cells from liquid culture. The activities in nitrogenase repressed cells were about 50% lower. Glutamine synthetase (E.C. 6.3.1.2.) activity in bacteroids and in nitrogenase active cells were also similar, but only about 25 — 30% of that found in nitrogenase repressed Rhizobium japonicum cells. | | | |
Reference
| Z. Naturforsch. 33c, 245 (1978); received February 9 1978 | | | |
Published
| 1978 | | | |
Keywords
| Rhizobium japonicum, Bacteroids, Derepressed Nitrogenase, Differentiation, N-Metabolism | | | |
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| | | | | TEI-XML for
| default:Reihe_C/33/ZNC-1978-33c-0245.pdf | | | | Identifier
| ZNC-1978-33c-0245 | | | | Volume
| 33 | |
| 3 | Author
| Renate Horcher, John Wilcockson, D. Ietrich, W. Erner | Requires cookie* | | | Title
| Screening for Mutants of Rhizobium japonicum with Defects in Nitrogen Fixing Ability | | | | Abstract
| Mutants o f Rhizobium japonicum with reduced ex planta nitrogenase activity could be isolated with high frequency by direct screening of ultra-violet mutagenized bacteria growing as spots on the surface o f an appropriate agar medium permitting derepression of nitrogenase synthesis. Small glass chambers fitted with a serum cap were pushed into the agar around each spot of growth, forming a small enclosed gas space which was made to 10% acetylene, permitting assessment o f nitrogenase activity by the acetylene reduction test. Four mutants were isolated from a total of 305 screened spots. Two mutants had almost no ex planta activity, one o f which had no symbiotic activity despite normal nodulation (ineffective), the other had only somewhat reduced activity symbiotically. Two other mutants with less than half wild-type activity ex planta were normal in symbiosis. | | | |
Reference
| Z. Naturforsch. 35c, 729—732 (1980); received May 30 1980 | | | |
Published
| 1980 | | | |
Keywords
| Rhizobium japonicum, Nitrogenase, Nif-Mutants, Ineffective Nodules | | | |
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| default:Reihe_C/35/ZNC-1980-35c-0729.pdf | | | | Identifier
| ZNC-1980-35c-0729 | | | | Volume
| 35 | |
| 4 | Author
| R. Stripf, D. W. Em Er | Requires cookie* | | | Title
| Development of Discontinuous Size Classes of Nodules of Glycine max | | | | Abstract
| In order to characterize developmental stages o f nodules of Glycine max nitrogenase activity in the variety Caloria, infected with Rhizobium japonicum 61-A -101, was studied in atmospheres with 19 and 40% 0 2. By the enhancement effect at 40% 0 2 four stages o f nodule development could be separated. Nitrogenase activity depends also among other things on nodule size. 3 -4 maxima in nodule number and nodule weight were found by fractionating nodules in 12 different size classes. Discontinuous size distribution was found with medium aged and old effective nodules. Nodule number (20 to 30) o f effective nodules per plant remains constant. Ineffective nodules remain far smaller than the effective ones, the number increases to more than 140 per plant and only one discontinuous size classe was observed. Bacteroids and plant cytoplasm from nodules of some size classes are characterized by their leghaemoglobin content and specific activity of enzymes o f nitrogen metabolism such as aspartate aminotransferase (E.C. 2.6.1.1), glutamate dehydrogenase (E.C. 1.4.1.2) and alanine de hydrogenase (E.C. 1.4.1.1). The data in the various size classes are similar both in the bacteroids and the plant cytoplasm, however, leghaemoglobin content and specific activity o f the bacterial enzyme alanine dehydrogenase are positively correlated with the increasing nodule size. | | | |
Reference
| Z. Naturforsch. 35c, 776—7 (1980); received May 30 1980 | | | |
Published
| 1980 | | | |
Keywords
| Rhizobium japonicum, Glycine max, Nodules Size Classes, Nitrogenase, Leghaemoglobin | | | |
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| | | | | TEI-XML for
| default:Reihe_C/35/ZNC-1980-35c-0776.pdf | | | | Identifier
| ZNC-1980-35c-0776 | | | | Volume
| 35 | |
| 5 | Author
| Dietrich Werner, W. Alburga, D. Ittrich, H. Eidem, ArieT. Hierfelder | Requires cookie* | | | Title
| Malonate and Krebs Cycle Intermediates Utilization in the Presence of other Carbon Sources by Rhizobium japonicum and Soybean Bacteroids | | | | Abstract
| Free living cells of Rhizobium japonicum 61-A-101 and bacteroids from Glycine max var. Mandarin infected with the same strain utilized malonate with a substrate saturation greater than 10~2 mol/1. At low concentrations of malonate (10~5 mol/1) the free living cells were significantly more active in utilizing malonate than bacteroids. In bacteroids two substrate saturation ranges were found, one between 3 x l 0 _4m ol/l and 10-3 mol/1, the other at more than 10-2 mol/1. Utilization of malonate was not affected by 10 to 100 times larger concentrations o f either arabinose or xylose. IO-3 mol/1 succinate inhibited the utilization o f malonate (10-4 mol/1) completely in bacteroids, and by 90% in free living cells. Succinate utilization (10-4 mol/1) was reduced in those cells exposed to 100 times higher malonate concentration only by 20-30% . Utilization and incorporation o f pyruvate and 2-oxoglutarate into bacteroids was also only slightly affected by 100 times larger malonate concentration. Citrate utilization by bacteroids however was reduced by more than 70%. The rate o f endoxidation o f malonate as sole carbon source (14C 0 2 production from [2-14C] malonic acid)was about 1.5 pmol • h-1 • mg protein-1 and about half the rate with Pseudomonas putida and 70% o f the rate with Pseudomonas fluorescens under the same conditions (pH 6.0, 28 °C). | | | |
Reference
| Z. Naturforsch. 37c, 921 (1982); received May 19 1982 | | | |
Published
| 1982 | | | |
Keywords
| Rhizobium japonicum, Rhizobium Bacteroids, Malonate Utilization, Organic Acids Utilization | | | |
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| default:Reihe_C/37/ZNC-1982-37c-0921.pdf | | | | Identifier
| ZNC-1982-37c-0921 | | | | Volume
| 37 | |
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