Cycloheximide induces synchronous swelling of perialgal vacuoles enclosing symbiotic Chlorella vulgaris and digestion of the algae in the ciliate Paramecium bursaria.
Cycloheximide is known to inhibit preferentially protein synthesis of symbiotic Chlorella of the ciliate Paramecium bursaria, but to hardly host protein synthesis. Treatment of algae-bearing Paramecium cells with cycloheximide induces synchronous swelling of all perialgal vacuoles that are localized immediately beneath the host's cell membrane. In this study, the space between the symbiotic algal cell wall and the perialgal vacuole membrane widened to about 25 times its normal width 24 h after treatment with cycloheximide. Then, the vacuoles detached from beneath the host's cell membrane, were condensed and stained with Gomori's solution, and the algae in the vacuoles were digested. Although this phenomenon is induced only under a fluorescent light condition, and not under a constant dark condition, this phenomenon was not induced in paramecia treated with cycloheximide in the light in the presence of the photosynthesis inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea. These results indicate that algal proteins synthesized in the presence of algal photosynthesis serve some important function to prevent expansion of the perialgal vacuole and to maintain the ability of the perialgal vacuole membrane to protect itself from host lysosomal fusion.
Kodama
Yuuki
Y
Department of Natural Science and Symbiosis, Graduate School of Science and Engineering, Yamaguchi University, Yoshida 1677-1, Yamaguchi 753-8512, Japan.
Fujishima
Masahiro
M
D000135:Acid Phosphatase / Q000378:metabolism; D020418:Algal Proteins / Q000378:metabolism; D000818:Animals; D002452:Cell Count; D048408:Chlorella vulgaris / Q000187:drug effects* / Q000502:physiology* / Q000528:radiation effects; D003513:Cycloheximide / Q000494:pharmacology*; D004063:Digestion; D008027:Light; D008247:Lysosomes / Q000187:drug effects / Q000502:physiology; D010247:Paramecium / Q000187:drug effects* / Q000502:physiology* / Q000528:radiation effects; D010788:Photosynthesis / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D013559:Symbiosis; D014617:Vacuoles / Q000187:drug effects / Q000502:physiology
D020418:Algal Proteins; D011500:Protein Synthesis Inhibitors; D003513:Cycloheximide; D000135:Acid Phosphatase