HISTOCHEMICAL AND ELECTRON MICROSCOPIC DIFFERENCES BETWEEN NATIVE GLYCOGEN AND POLYGLUCOSE SYNTHESIZED BY PHOSPHORYLASE IN TISSUE CELLS

Abstract

Polysaccharide formed histochemically from glucose 1-phosphate by the enzyme activity and native glycogen were observed under the electron microscope.
Polyglucose newly formed only by phosphorylase in rat muscle fibers was stained blue with iodine and appeared to be a finer granular evidence showing ambiguous particles with a diameter from 100Å to 150Å, while native glycogen stained red brown with iodine was demonstrable in mono- particulate form with diameter from 200Å to 400Å.
Polysaccharides synthesized by phosphorylase and branching enzyme in rat liver and hepatoma cells were stained red purple with iodine and were demonstrable in the same ambiguous granular form with a diameter from 100Å to 200Å, while native glycogen appeared to form so-called glycogen rosettes.
In the methacrylate-embedded sections, the newly synthesized polyglucose was more sensitive to the electron beam and thereby was more easily degraded and missed in the cells than native glycogen. When using the Epon embedding the resistance of both substances to the electron beam increased markedly. Nevertheless, the newly formed polyglucose was less resistant to the beam than native glycogen. Furthermore, the synthe-sized polyglucose had difficult staining with lead hydroxide, while glycogen stained densely with it. It was, therefore, newly found that polyglucose synthesized from glucose 1-phosphate by the enzyme activity is obviously different from native glycogen, contrary to Leloir's in-vitro observation.