The Fine Structure of Kappa in Killer Stock 51 of Paramecium aurelia. Preliminary Observations

Abstract

Two types of kappa bodies, corresponding to the "brights" and "non-brights" described by Preer, were observed in electron micrographs of thin sections of killer animals fixed in buffered osmium and embedded in methacrylate. A wispy, filamentous material associated with minute granules and small, extremely dense particles of irregular shape were found in both types but were present in much greater concentration in "non-bright" forms. "Brights", associated with paramecin production, contained a refractile body comprised of cylindrically coiled lamellae enclosing a central core of dense, granular material. Attention was called to the possible relation between kappa and symbiotic bacterial forms known to produce exotoxins and to contain inclusion bodies associated with toxic activity.