degradation of dry matter (dm) and nitrogen (n) in fresh or frozen-thawed alfalfa and ryegrass was studied by using in situ technique. the forages were labeled with 15n during growth in a glasshouse, harvested at similar growth phase, and fresh (f) or frozen-thawed (ft) samples were incubated in the rumen of 3 sheep. there was no difference (p>0.05) between forage type (s) for the immediately s...

Degradation of dry matter (DM) and nitrogen (N) in fresh or frozen-thawed alfalfa and ryegrass was studied by using in situ technique. The forages were labeled with 15N during growth in a glasshouse, harvested at similar growth phase, and fresh (F) or frozen-thawed (FT) samples were incubated in the rumen of 3 sheep. There was no difference (P>0.05) between forage type (S) for the immediately s...

L are used commonly in agricultural systems Legume mulches are important sources of N for cereal crop producas a source of N for subsequent crops and for maintion, particularly for organic and resource-poor producers. A field taining soil N levels. This use is particularly important study was conducted using a direct method to determine if the amount in the humid tropics where N fertilizers oft...

The biosynthesis of the azamacrolide epilachnene by the coccinellid beetle Epilachna varivestis has been studied with 2H-labeled oleic acid, 2H-labeled L-serine, and 13C,15N-labeled L-serine. The incorporation of these precursors into epilachnene defines the origin of the alkaloid's entire carbon/nitrogen skeleton. GC/MS and GC/IR studies of alkaloid produced by Epilachna fed with deuteriated o...

Methods have been developed for identifying the pathway of assimilation of N2-derived nitrogen. The products of fixation of 13N-labeled nitrogen gas ([13N]N2), and the distribution of 13N within glutamine, were determined after short periods of labeling (approximately 1 to 120 s) and also in pulse-chase experiments. Ammonia, the amide nitrogen of glutamine, and the alpha-amino nitrogen of gluta...

The cell surface of Azospirillum brasilense was probed by using fluorescein isothiocyanate (FITC)-labeled lectins, with binding determined by fluorescence-activated flow cytometry. Cells from nitrogen-fixing or ammonium-assimilating cultures reacted similarly to FITC-labeled lectins, with lectin binding in the following order: Griffonia simplicifolia II agglutinin > Griffonia simplicifolia I ag...

Solid molecular nitrogen (N2) may exist in large abundances in various low-temperature interstellar and solar system environments. Intense radiation fields can cause molecular nitrogen ice to undergo chemical alterations by cleaving the nitrogen–nitrogen triple bond. We have simulated this chemical processing by carrying out radiolysis experiments using energetic electrons on molecular nitrogen...