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Structure and function in the euglenoid eyespot apparatus: The fine structure, and response to environmental changes


The microanatomy of the eyespot apparatus of Euglena gracilis Z was examined with the electron microscope. The stigma was found to be a membrane-bounded organelle showing no close homology with the chloroplast or any other organelle. The structure and pigment content of the stigma both diminish with extended hetrotrophic growth, and quickly regain normal dimensions upon exposure to light. Synthesis of the red pigment is particularly sensitive to inhibition by chloramphenicol, whereas construction of the structure itself is specifically inhibited by cycloheximide.

The paraflagellar body appears to consist of two sets of parallel 80 Å striations intersecting at 60°. It is within the flagellar membrane, but separated from the axoneme by another structure, the paraflagellar rod. This elongated structure has an ordered substructure which appears as intersecting sets of parallel striations; part of its basal portion projects as a circular flange which makes contact with the paraflagellar body.

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  1. Bishop, D. G., Smillie, R. M.: The effect of chloramphenicol and cycloheximide on lipid synthesis during chloroplast development in Euglena gracilis. Arch. Biochem. 139, 179–189 (1970).

  2. Buetow, D. E.: Morphology and ultrastructure of Euglena. In: The biology of Euglena, vol. 1, p. 110–186, D. E. Buetow, ed. New York: Acad. Press 1968.

  3. Ennis, H. L., Lubin, M.: Cycloheximide: aspects of inhibition of protein synthesis in mammalian cells. Science 146, 1474–1476 (1964).

  4. Fawcett, D.: Cilia and flagella. The cell, vol. II, p. 217–298, J. Brachet and A. E. Mirsky, eds. New York: Acad. Press 1961.

  5. Gale, E. F.: Mechanisms of antibiotic action. Pharmacol. Rev. 15, 481–530 (1963).

  6. Gibbs, S. P.: The fine structure of Euglena gracilis with special reference to the chloroplasts and pyrenoids. J. Ultrastruct. Res. 4, 127–148 (1956).

  7. Gozdics, M.: The cell morphology of Euglena deses (Ehrenburgh). Amer. Mic. Soc. Trans. 53, 299–310 (1934).

  8. Hall, R. P., Jahn, T. L.: Dispersed stages of the stigma in Euglena. Science 69, 522 (1929).

  9. Hall, S. R.: Observations on Euglena leucops sp. nov. a parasite of Stenostomum, with special reference to nuclear division. Biol. Bull. 60, 327–344 (1931).

  10. Hutner, S. H., Bach, M. K., Ross, G. I. M.: A sugar-containing basal medium for vitamin B12 assay with Euglena; application to body fluids. J. Protozool. 3, 101–112 (1956).

  11. Jahn, T. L., Bovee, E. C.: Locomotive and motile response in Euglena. In: The biology of Euglena, vol. 1, p. 45–108, D. E. Buetow, ed. New York: Acad. Press 1968.

  12. Leedale, G. F.: Euglena: A new look with the electron microscope. Advanc. Sci. 23, 22–37 (1966).

  13. Leedale, G. F.: Euglenoid flagellates. Edgewood Cliffs: Prentice-Hall 1967.

  14. Pringsheim, E. G.: Contributions towards a monograph of the genus Euglena. Nova Acta Leopoldina 125, 1–168 (1956).

  15. Pringsheim, E. G., Pringsheim, O.: Experimental elimination of chromatophores and eyespot in Euglena gracilis. New Phytologist 51, 65–76 (1952).

  16. Smillie, R. M., Graham, D., Dwyer, M. R., Grieve, A., Tobin, N. F.: Evidence for the synthesis in vivo of proteins of the Calvin cycle and of the photosynthetic electron transfer pathway on chloroplast ribosomes. Biochem. biophys. Res. Commun. 28, 604–610 (1967).

  17. Smillie, R. M., Scott, N. S.: Organelle biosynthesis: the chloroplast. In: Progress in molecular and subcellular biology, vol. I, p. 136–202, F. E. Hahn, ed. Berlin-Heidelberg-New York: Springer 1969.

  18. Spurr, A. R.: A low-viscosity epoxy resin embedding medium for electron microscopy. J. Ultrastruct. Res. 26, 31–43 (1969).

  19. Wager, H.: On the eyespot and flagellum in Euglena viridis. J. Linn. Soc. (Zool.) 27, 463–481 (1900).

  20. Walne, P. L., Arnott, H. J.: The comparative ultrastructure and possible function of eyespots: Euglena granulata and Chlamydomonas eugametos. Planta (Berl.) 77, 325–353 (1967).

  21. Wolken, J. J.: Vision: biophysics and biochemistry of the retinal photoreceptors. Springfield: Charles C. Thomas 1966.

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Kivic, P.A., Vesk, M. Structure and function in the euglenoid eyespot apparatus: The fine structure, and response to environmental changes. Planta 105, 1–14 (1972).

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  • Electron Microscope
  • Environmental Change
  • Fine Structure
  • Chloramphenicol
  • Flange