Disruption of Chemically Killed Bacterial Cells by a Synthetic Zeolite

The applicability of a synthetic zeolite (type 4A, Union Carbide Corp., Linde Div., New York, N.Y.) as a disruptive agent in a procedure for the preparation of pure bacterial cell wall fractions from a variety of phenol-killed gram-negative, gram-positive, and acid-fast bacteria was demonstrated. The disruptive effect was found to be limited with formaldehyde-killed gram-positive cells and most gram-positive cocci killed either by phenol or formaldehyde.     

Disruption of Bacterial Cells by a Synthetic Zeolite

The use of a synthetic zeolite (type 4A, Union Carbide Corp., Linde Div., New York, N.Y.) in a procedure for the preparation of pure cell wall fractions proved successful for many gram-positive, gram-negative, and acid-fast bacteria, as well as for some fungi. The technique, however, was found to be limited in effectiveness for Rhodospirillum rubrum, Gaffkya tetragena, and Sarcina lutea, and not applicable to preparations of heat killed microorganisms. The possible mechanisms of zeolite action, together with the effect of the disruptive procedure on the chemical composition of cell wall fragments, were investigated also.     

Saturated hydrocarbons in bovine liver

A homologous series of n-alkanes (C(14)-C(33)) and two isoprenoid hydrocarbons, 2,6,10,14-tetramethylhexadecane (phytane) and 2,6,10,14-tetramethylpentadecane (pristane) have been identified in bovine liver. Another branched but non-isoprenoid alkane and three isomers of molecular formula C(20)H(40) were partially identified. Phytane and the C(18)-C(22) and C(29)-C(33)n-alkanes were found to be the major components in liver, suggesting that at least the main hydrocarbon components were derived from various plants in the diet. The hydrocarbons were separated and identified by a series of steps involving solvent extraction, saponification, elution chromatography on alumina and silica gel columns, molecular sieving and by infrared and ultraviolet spectroscopy, followed by combined capillary gas chromatography-mass spectrometry.     

Preferential utilization of ammonium over nitrate by micro-organisms in the decomposition of oat straw

Summary Ammonium was compared with nitrate as a source of nitrogen for micro-organisms in the decomposition of oat straw. When both ions were added in sufficient and equal quantities the organisms utilized the ammonium ion almost exclusively. The relative absorption of the two ions was determined by means of tagged nitrogen.Ammonium was also found to promote a greater total immobilization of nitrogen and more rapid decomposition of the oat straw under a wide range of environmental conditions. The results suggest that ammonium may be preferable to nitrate in the production of composts and to have certain advantages when nitrogen is applied to promote decomposition of crop residues.Journal Paper J-2461, Project 1070 of the Iowa Agricultural Experiment Station. This work was supported in part by the Royal Agricultural College, Uppsala 7, Sweden, and was performed while the senior author was an Exchange Visitor at Iowa State College.