It is well demonstrated that the responses of plants to elevated atmospheric CO(2) concentration are species-specific and dependent on environmental conditions. We investigated the responses of a subshrub legume species, Caragana microphylla Lam., to elevated CO(2) and nitrogen (N) addition using open-top chambers in a semiarid temperate grassland in northern China for three years. Measured var...

Development of nitrogenase (40--140 nmol C2H4.mg protein-1.h-1) in Rhizobium japonicum 61-A-101 after transfer to special culture conditions (medium 20 P, 2% O2, 10% CO2, 88% N2 in the gas phase) is inhibited by chloramphenicol (6 X 10(-4)--10(-3) M) and by rifampicin (10(-5) M). These concentrations do not inhibit the slow growth of the cells under these conditions with a doubling time of the ...

74 overlapping peptides of varying lengths from Klebsiella pneumoniae nitrogenase reductase (residues 181-199) and from the HLA B27.1 molecule (residues 65-85) were synthesized and tested by ELISA against sera from HLA B27+ ankylosing spondylitis (AS) patients, and sera from HLA B27+ and HLA B27- healthy first-degree relatives. Antibody activity in AS sera to Klebsiella peptides of four to eigh...

In whole cells of Rhodopseudomonas sphaeroides, nitrogen fixation, as measured by hydrogen production and acetylene reduction, was totally inhibited by micromolar concentrations of ammonia. This inhibition could not be duplicated by glutamate or glutamine alone. The inhibition by ammonia was abolished by methionine sulfoximine, a glutamine synthetase inhibitor. Inhibition by glutamine was compl...

Rhizobium japonicum, Glycine max, Nodules Size Classes, Nitrogenase, Leghaemoglobin In order to characterize developmental stages of 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 of nodule development could be separated. Nitrogenase ...

In many environments, biological nitrogen fixation can alleviate nitrogen limitation. The high rates of N(2) fixation often observed in cyanobacterial mats suggest that N(2) fixation may be an important source of N. In this study, organisms expressing nifH were identified in a Lyngbya sp.- and two Microcoleus chthonoplastes-dominated cyanobacterial mats. The pattern of nitrogenase activity was ...

Nitrogen fixation (acetylene reduction) associated with roots of the seagrass Halodule wrightii was measured offshore near Beaufort and Moorhead City, N.C. Rates of acetylene reduction were higher in aerobic than in anaerobic assays and were linear for up to 5 days. The temperature range for acetylene reduction was 15 to 35 degrees C with a maximum activity at 35 degrees C. Nitrogenase activity...