An Alternative Method of Isolating the Membrane of a Halophilic Bacterium

Abstract

SUMMARY: The membrane of Halobacterium halobium was isolated after rupturing the organisms osmotically in 0.02 M-MgCl₂. Selected properties of this membrane were compared with those of membranes isolated from organisms which had been ruptured mechanically in 5 M-NaCl. The two types of preparation were indistinguishable from one another in the electron microscope, but some differences were noted between the present series of preparations and those described earlier. These differences, of which the occasional retention of the characteristic surface pattern of this organism was notable, were attributed to a slight modification of fixation conditions used in the present work. There were no major chemical differences between the two types of preparation but some minor differences in H⁺ titration and carbohydrate analyses possibly reflected slight structural differences between the two types of preparation. The osmotic method described here is much quicker than the mechanical one and, unlike the mechanical one, the time involved is largely independent of the quantity of organisms being used.