Protocorm pieces of the orchid Cymbidium were aseptically cultured either without phytohormones, or with one of the growth promoting substances, auxin cytokinin, and gibberellin. The derivative melting profiles of the extracted DNA's differ from each other with respect to the size of various AT- and GC- rich fractions. Evidence has been obtained for the increase of the more AT--rich fractions i...

The ultrastructure of ciliary muscle was studied in an old, healthy crabeating monkey. In the cytoplasm, large swollen mitochondria, interdigitated mitochondria, various types of myelin-like figures, dense coarse membranous structures, lysosomal dense bodies, round lipid-like bodies, transitional forms from lysosomal dense bodies to lipid-like bodies, lipofuscin pigments, whorl-like structures ...

Kappas (bacterial symbionts containing R bodies) have been studied in 16 strains of Paramecium aurelia, syngens 2 and 4. All produce toxins capable of killing sensitive paramecia. The first major class, the 51 group (consisting of the kappas of strains 51, 116, and 298), has R bodies which, when the pH is lowered below 6-5, unwind reversibly from the inside to form a tight tube; the outside end...