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Azoarcus sp. strain BH72 is an aerobic diazotrophic bacterium that was originally found as an endophyte in Kallar grass. Anticipating that these bacteria are exposed to dissolved O2 concentrations (DOCs) in the nanomolar range during their life cycle, we studied the impact of increasing O2 deprivation on N2 fixation and respiration. Bacteria were grown in(More)
Studies of nitrogenase in cultures of the cowpea rhizobia (Rhizobium spp.) strains 32H1 and CB756 are reported. Preliminary experiments established that, even when agar cultures were grown in air, suspensions of bacteria prepared anaerobically from them were most active at low concentrations of free dissolved O2. Consequently, assays for activity used low(More)
BACKGROUND Atracurium has four chiral centers and the marketed product is a mixture of ten optical and geometric isomers. Six of the isomers were prepared and evaluated for neuromuscular blocking activity and autonomic effects in anesthetized cats. This study reports the comparative pharmacology of the six isomers and atracurium that led to the selection of(More)
In samples from nitrogen-fixing continuous cultures of strain CB756 of the cowpea type rhizobia (Rhizobium sp.), newly fixed NH+4 is in equiblibrium with the medium, from where it is assimilated by the glutamine synthetase/glutamate synthase pathway. In samples from steady state cultures with different degrees of oxygen-limitation, nitrogenase activity was(More)
Studies of rates of consumption of dissolved O2 by suspensions of bacteroids (Rhizobium japonicum, strain CB1809) from soybean root nodules showed the presence of two different terminal oxidase systems. A high-affinity system, sensitive to inhibition by N-phenylimidazole and by carbon monoxide, was most active when the dissolved O2 was between 0-01 and 0-1(More)
A liquid reaction medium containing dissolved air and oxyleghaemoglobin, but no energy-yielding substrate, was supplied to bacteroids confined in a stirred flow reaction chamber. The relative oxygenation of the leghaemoglobin in the chamber was determined automatically by spectrophotometry of the effluent solution, and the concentrations of free, dissolved(More)