Effects of nitrogen and phosphorus fertilization on the activities of four different classes of fine-root and soil phosphatases in Bornean tropical rain forests

Plant and Soil - Soil hydrolysable P can be a main P source for biota in P-limited tropical rain forests. Soil hydrolysable P occurs in various chemical fractions, including, monoester P, diester...     

Effects of sugarcane trash and pineapple residue incorporation on soil nitrogen,pH and redox potential

Summary Sugarcane trash and pineapple residue, in a finely ground state, were mixed with soil at different levels with and without nitrogen fertilization. The nitrogen treatments received 112 kg N/ha as ammonium sulfate. The samples were incubated for different lengths of time (up to 16 weeks) and analyzed for total, ammonium, nitrate and nitrite nitrogen, pH and redox potential.There was no noticeable loss of nitrogen from the samples due to denitrification. The concentration of ammonium and nitrate nitrogen remained very low throughout the incubation study, probably due to immobilization by soil microflora. After 12 weeks, there was some indication of the release of mineral nitrogen from immobilized reserves. The redox potential was found to be between 400–600 mv during this study and nitrates became unstable below 400 mv redox potential.Journal Series No. 1647 of Hawaii Agricultural Experiment Station, Honolulu, Hawaii 96822. This paper is based on the M.S. Thesis of the senior author: Organic matter decomposition and redox potential relationships in a Hawaiian Oxisol, University of Hawaii, 1972.     

Separation of DNA-dependent DNA polymerase activities in Micrococcus radiodurans.

DNA polymerase activities in Micrococcus radiodurans were separated into two fractions after purification more than 2000 fold. They differ in pH optimum and residual activities in the absence of a full deoxyribonucleoside triphosphates complement. NAD partly inhibited one of the activities. Both activities were eluted as a single peak on gel filtration and sedimented at the same rate on glycerol gradient centrifugation. Molecular weight 140000 was calculated from Stokes radius and sedimentation constant. Deoxyribonuclease activity was detected on one of the polymerase activities which preferentially degraded double-stranded DNA. Priming activity of nicked DNA was reduced by gamma-irradiation. These results have been related to the possible rolls in repair synthesis in vivo or DNA synthesis in permeable cells of M. radiodurans.     

Chemistry of zerumbone. 2. Regulation of ring bond cleavage and unique antibacterial activities of zerumbone derivatives.

Further investigation of the chemistry of the eleven-membered cyclic sesquiterpene, zerumbone, the major component of the wild ginger, Zingiber zerumbet Smith, has revealed a new selective epoxidation process, a further example of a novel Favorskii-initiated double ring contraction, and a regiospecific fragmentation of zerumbone dibromide derivatives. Several zerumbone derivatives were found to be selective inhibitors of the growth of gram-positive bacteria.