FACTORS AFFECTING THE VIABILITY OF AIR-BORNE BACTERIA: III. THE ROLE OF BONDED WATER AND PROTEIN STRUCTURE IN THE DEATH OF AIR-BORNE CELLS

Abstract

The relationship between cellular water and the death of air-borne cells, and the effect of added substances on these relationships, has been studied. The rate of death of air-stored cells has been correlated with the amount of water bonded to the cellular proteins. Refractive indices of cells, measured by light scatter and interferometry, have suggested that cells suspended in solutions of various compounds contain less water. With the exception of urea, the more able a compound is in displacing water, the less its protectiveness to air-borne cells. Inositol produced the smallest change in the water content and refractive index of cells. This is taken to indicate that, in the absence of water, this compound can form hydrogen bonds with cellular protein which are reversible with water. There appears also to be some relationship between the Gram stain reaction and aerosol stability of the cells. Ribonuclease and lysozyme treatment of air-stable cells rendered them air sensitive, whereas resistance to some antibiotics, and suspension in some antibiotics, afforded stability to air-sensitive cells. It is suggested that the site of damage is the cellular "membranes" which break down on desiccation and result in a loss of differentiation within the cell.