Disintegration of chloroplasts with dodecylbenzene sulfonate as measured by flattening effect and size distribution

Abstract

New techniques for the optical measurement of the mean radius of colored particles by the flattening effect and the electric measurement of volume distribution with the Coulter counter were applied to the determination of the size of spinach chloroplasts and grana and the particles derived from them by treatment with dodecylbenzene sulfonate. The whole process of disintegration and solubilization of chloroplasts to chlorophyll holochrome was followed by these techniques and by ultracentrifugal analysis. By treatment with dodecylbenzene sulfonate, the native chloroplasts were swollen and then disintegrated into swollen grana. The electron micrograph of the swollen chloroplasts inverted that each lamella is swollen into a globular particle inside the chloroplasts. The swollen grana were disintegrated with dodecylbenzene sulfonate into smaller particles which were then transformed into a component of 2.9–3.5 S. This component by treatment with a more concentrated dodecylbenzene sulfonate dissociated intercomponents of 1.2 S which are the smallest units obtainable with the detergent. The size of native and swollen chloroplasts and grana, determined by the new techniques were discussed.