Accession Number : AD0673400

Title :   BIOPHYSICAL STUDIES OF MICROBIAL CELL WALLS. PART I. THE PREPARATION OF ISOLATED CELL WALLS,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Neihof,R. A. ; Echols,W. H.

Report Date : 19 JUN 1968

Pagination or Media Count : 33

Abstract : A biophysical characterization of microbial cell walls can be greatly facilitated by the availability of walls free from other cell constituents. Isolated cell walls for this purpose are best prepared by rupturing the microbial cell by mechanical means, removing soluble cytoplasmic constituents by washing, and subsequently separating the walls from unbroken cells and particulate debris by centrifugation. In this investigation methods were explored for the efficient rupture, without undue fragmentation, of typical microorganisms using violent agitation with small glass beads effected by high-speed stirring or by shaking in a commercial cell homogenizer. The extent of rupture of the microorganisms was measured by viability loss, microscopic appearance, turbidity, and the ultraviolet adsorption of released cytoplasmic constituents. Clean fractionations of cell walls with minimum losses were accomplished by centrifugation on preformed density gradients of solutions of selected salts and nonelectrolytes. The purity of the final cell-wall product was assessed by light and electron microscopy and by the ultraviolet light adsorption of acid extracts. Autolytic degradation of the walls was minimized by maintaining low temperatures during all stages of preparation. The cell walls of Gram-positive organisms met all of the criteria of purity; those from Gram-negative organisms were less homogeneous. (Author)

Descriptors :   (*CELL WALL, *BIOPHYSICS), MICROORGANISMS, BACTERIA, YEASTS, RUPTURE, CELL STRUCTURE, CENTRIFUGE SEPARATION, MORPHOLOGY(BIOLOGY), ADSORPTION, ULTRAVIOLET RADIATION

Subject Categories : Biology
      Microbiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE