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The methodology, characteristics and application of the sensitive C(2)H(2)-C(2)H(4) assay for N(2) fixation by nitrogenase preparations and bacterial cultures in the laboratory and by legumes and free-living bacteria in situ is presented in this comprehensive report. This assay is based on the N(2)ase-catalyzed reduction of C(2)H(2) to C(2)H(4), gas(More)
DNA-based typing of HLA class I alleles of the HLA-A and HLA-B loci using sequence-specific oligonucleotide primers and/or probes has been used for the large-scale typing of individuals for the National Marrow Donor Program unrelated donor registry. Typing was performed by 16 laboratories at a low level of resolution (e.g. A*01, B*07). The results of(More)
Aged rodents compared to young rodents are impaired in making repeated reversals and more variable in performance on many tasks. In the present study, a comparison of ten aged (21 months) and 10 young (3 months) Sprague-Dawley rats on a repeated spatial discrimination reversal water escape task revealed that the deficient and variable performance of the(More)
1. Characteristics and methodology of the C2H2-C2H4 assay forin situ measurement of N2 fixation are outlined. 2. Electron micrographic analysis of the developmental morphology of the natural soybean symbiosis and C2H2-C2H4 analysis indicate that increasing N2-fixing activity from 12–35 days of age is accompanied by an increase in bacteroid number per cell,(More)
Glucose has previously been shown to improve performance on memory tasks and to ameliorate performance deficits induced by scopolamine or morphine. To test the generality of these observations, Sprague-Dawley rats were trained to alternate choices to reach an escape platform in a two-choice circular water maze. The rats attained a high level of alternation,(More)