Rhizobium japonicum derivatives differing in nitrogen-fixing efficiency and carbohydrate utilization

Screening for mutants of Rhizobium japonicum with defects in nitrogen fixing ability.

Mutants of 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 of 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 ...

Nitrogen, energy and vitamin nutrition of Rhizobium japonicum.

The energy, nitrogen and vitamin nutrition of 36 strains of Rhizobium japonicum were investigated. Most of the strains utilized gluconate, glycerol, arabinose, glucose, mannose, mannitol, sorbitol, galactose and maltose. Pyruvate, succinate, ribose, ribitol, xylose, fructose and lactose were of limited use whereas acetate, propionate, lactate, malate, citrate and sucrose were uniformly inadequa...

Conservation of symbiotic nitrogen fixation gene sequences in Rhizobium japonicum and Bradyrhizobium japonicum.

Southern hybridization with nif (nitrogen fixation) and nod (nodulation) DNA probes from Rhizobium meliloti against intact plasmid DNA of Rhizobium japonicum and Bradyrhizobium japonicum strains indicated that both nif and nod sequences are on plasmid DNA in most R. japonicum strains. An exception is found with R. japonicum strain USDA194 and all B. japonicum strains where nif and nod sequences...

Lxxiv. the Occurrence of Nucleic Acid Derivatives in Nitrogen-fixing

Determination of Hydrogenase in Free-living Cultures of Rhizobium japonicum and Energy Efficiency of Soybean Nodules.

A sensitive tritium exchange assay was applied to the Rhizobium system for measuring the expression of uptake hydrogenase in free-living cultures of Rhizobium japonicum. Hydrogenase was detected about 45 hours after inoculation of cultures maintained under microaerophilic conditions (about 0.1% O(2)). The tritium exchange assay was used to screen a variety of different strains of R. japonicum (...