Effect of K2Cr2O7 on the photosynthetic activity and mobility of Euglena gracilis Klebs cells

The pellicular structure of Euglena gracilis consists of a series of relatively rigid strips (Fig. 1) composed of ridges and grooves which are helically oriented along the cell and which fuse together into a common junction at either end of the cell. The strips are predominantly protein and consist in part of a series of fibers about 50 Å in diameter spaced about 85 Å apart and with a secondary periodicity of about 450 Å. Microtubules are also present below each strip (Fig. 1) and are often considered as part of the pellicular complex. In addition, there may be another fibrous component near the base of the pellicle which has not yet been very well defined.The pellicular complex lies underneath the plasma membrane and entirely within the cell (Fig. 1). Each strip of the complex forms an overlapping junction with the adjacent strip along one side of each groove (Fig. 1), in such a way that a certain amount of sideways movement is possible between one strip and the next.

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Immunocytochemical studies on the behavior of RuBisCO and LHCP II during the cell cycle of synchronized Euglena gracilis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160868 ◽

1990 ◽

Vol 48 (3) ◽

pp. 662-663

Author(s):

Tetsuaki Osafune ◽

Shuji Sumida ◽

Tomoko Ehara ◽

Eiji Hase ◽

Jerome A. Schiff

Keyword(s):

Cell Cycle ◽

Immunoelectron Microscopy ◽

Growth Phase ◽

Euglena Gracilis ◽

Dark Period ◽

Light Period ◽

Carboxylase Activity ◽

Immunocytochemical Studies ◽

Lhcp Ii

Changes in the morphology of pyrenoid and the distribution of RuBisCO in the chloroplast of Euglena gracilis were followed by immunoelectron microscopy during the cell cycle in a light (14 h)- dark (10 h) synchronized culture under photoautotrophic conditions. The imrnunoreactive proteins wereconcentrated in the pyrenoid, and less densely distributed in the stroma during the light period (growth phase, Fig. 1-2), but the pyrenoid disappeared during the dark period (division phase), and RuBisCO was dispersed throughout the stroma. Toward the end of the division phase, the pyrenoid began to form in the center of the stroma, and RuBisCO is again concentrated in that pyrenoid region. From a comparison of photosynthetic CO2-fixation with the total carboxylase activity of RuBisCO extracted from Euglena cells in the growth phase, it is suggested that the carboxylase in the pyrenoid functions in CO2-fixation in photosynthesis.

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Three-dimensional distribution of ribulose-1, 5-bisphosphate carboxylase/oxygemase during the early development of proplastids in dark-grown Euglena cells transferred to an inorganic medium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100162090 ◽

1990 ◽

Vol 48 (3) ◽

pp. 906-907

Author(s):

Tomoko Ehara ◽

Shuji Sumida ◽

Tetsuaki Osafune ◽

Eiji Hase

Keyword(s):

Cell Suspension ◽

Euglena Gracilis ◽

Carbon Materials ◽

Three Dimensional ◽

Peripheral Region ◽

Plastid Development ◽

Bisphosphate Carboxylase ◽

Inorganic Medium ◽

Ribulose 1 ◽

Dimensional Distribution

As shown previously, Euglena cells grown in Hutner’s medium in the dark without agitation accumulate wax as well as paramylum, and contain proplastids showing no internal structure except for a single prothylakoid existing close to the envelope. When the cells are transferred to an inorganic medium containing ammonium salt and the cell suspension is aerated in the dark, the wax was oxidatively metabolized, providing carbon materials and energy 23 for some dark processes of plastid development. Under these conditions, pyrenoid-like structures (called “pro-pyrenoids”) are formed at the sites adjacent to the prolamel larbodies (PLB) localized in the peripheral region of the proplastid. The single prothylakoid becomes paired with a newly formed prothylakoid, and a part of the paired prothylakoids is extended, with foldings, in to the “propyrenoid”. In this study, we observed a concentration of RuBisCO in the “propyrenoid” of Euglena gracilis strain Z using immunoelectron microscopy.

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