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'Rhizobium japonicum' in keywords Facet   Publication Year 1980  [X]
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1Author    Renate Horcher, John Wilcockson, D. Ietrich, W. ErnerRequires 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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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0729.pdf 
 Identifier    ZNC-1980-35c-0729 
 Volume    35 
2Author    R. Stripf, D. W. Em ErRequires 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., glutamate dehydrogenase (E.C. and alanine de­ hydrogenase (E.C. 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