A relatively simple and rapid procedure for the measurement of free ammonium and the amides in plant extracts is described. The method was developed by combining a cation-exchange method for blood ammonia with a differential acid-hydrolysis procedure for asparagine and glutamine amide-nitrogen. The recovery of standard samples (100-400 mug of ammonium- or amide-nitrogen) of free ammonium, aspar...

Ammonium production in the presence of specific inhibitors of sulfate reduction and methanogenesis was investigated in six marine sediments which differed in bulk properties and organic matter input. In all cases, little effect of the inhibitors on ammonium production was observed, although sulfate reduction was suppressed by molybdate. This gives evidence that the processes of fermentation and...

Ammonia oxidation in laboratory liquid batch cultures of autotrophic ammonia oxidizers rarely occurs at pH values less than 7, due to ionization of ammonia and the requirement for ammonium transport rather than diffusion of ammonia. Nevertheless, there is strong evidence for autotrophic nitrification in acid soils, which may be carried out by ammonia oxidizers capable of using urea as a source ...

Three human isolates of Vibrio succinogenes produced asparaginase. Apparent Km's were 87,220, and 320 microM. The rate of glutamine hydrolysis was between 2.8 and 3.5% of the rate of asparagine hydrolysis. Asparaginase production was not induced by ammonium ions, and enzyme yields were lower than those obtained with the rumen strain.

A hemicellulose is any of several heteropolymers , such as arabinoxylans, present along with cellulose in almost all plant cell walls. Hemicellulose has a random, amorphous structure with little strength. It is easily hydrolyzed by dilute acid or base as well as myriad hemicellulase enzymes. In this study, lignin and hemicellulose was extracted from sugarcane bagasse using the ammonium hydrolys...

Mesoporous hybrid silica bearing zwitterionic species were synthesized via template-directed hydrolysis-polycondensation reactions from zwitterionic ammonium sulfonate precursors. The formation of the nanostructured phases involves specific precursor-template interactions. The obtained materials are efficient heterogeneous catalysts in Biginelli reactions.