Shuji Sumida

Behaviour of proplastids and their nucleoids in dark-organotrophically grown cells of Euglena gracilis transferred to an inorganic medium

Euglena gracilis Z cells in the stationary phase of dark-organotrophic growth in a culture without agitation were rich in lipid, and contained six to eight proplastids dispersed in the cytoplasm (A-type proplastids). When these cells were transferred to an inorganic medium and aerated in darkness, they showed, with the disappearance of lipid, diphasic increase in number after an induction phase, concurrently with the development of prolamellar bodies and some primary thylakoids in their proplastids. The proplastids and their nucleoids, examined under a fluorescence microscope with and without staining with the DNA fluorochrome, 4′,6-diamidino-2-phenylindole, showed dynamic and sequential morphological changes. Before the first cell doubling, the A-type proplastids gathered to form three to four aggregates (B-type), that were themselves connected into a single elongated form with intricate windings and branchings (C-type). The nucleoid in the C-type proplastid was present as a branched string winding throu...

Development of Proplastids and Accumulation of LHCP II Apo-Protein in Golgi and Thylakoids of Dark-Grown Wax-Rich Cells of Euglena Gracilis at Low Light Intensities seen by Immuno-Electron Microscopy

When dark-grown resting cells of Euglena are exposed to light at the low intensity threshold of chloroplast development(7 ft-c) the antennas, including the LHCP II 26.5 kD apoprotein are very low or undetectable, but on exposure of these cells to more normal intensities of light for development (80–150 ft-c) the antennas, including the LHCP II apoprotein and chlorophyll b rapidly accumulate 1. Thin sections of similar cells at 3–7 ft-c do not show appreciable staining of either Golgi or thylakoids with rabbit immune serum against the 26.5 kD apoprotein plus protein A-gold, but when these cells are incubated at 80–150 ft-c specific staining with immunogold rapidly appears in both the Golgi and the thylakoids 2,3.

Low Intensity Light-Induced Development of Thylakoids in Proplastids of Dark-Grown Wax-Rich Cells of Euglena Gracilis

As shown previously 1,2), dark-grown, wax-rich cells of Euglena gracilis contain profoundly degenerate proplastids with no internal structure except for a single prothylakoid lying close to the envelope. When these cells are transferred to an inorganic medium containing ammonium salt as nitrogen source and aerated in darkness for 5 to 6 days, an early development of proplastids occurs using wax (and paramylum) as sources of carben and energy 3). The early development includes formation of rudimentary pyrenoid (propyrenoid) at the site adjacent to the prolamellar body, which appears earlier in the peripheral region of the proplastid. The peripheral single prothylakoid becomes paired along part of its length, and a portion of the paired prothylakoid becomes extended and enfolded in the propyrenoid. No further development of proplastids was observed during prolonged dark incubation of these Euglena cells. This paper describes the observations made when these dark-incubated Euglena cells were exposed to light at different intensities including the low intensity threshold (3–7 ft-c) for chloroplast development 4).

Immunogold Localization of Ribulose-1, 5-Bisphosphate Carboxylase in Synchronized Cells of Euglena gracilis Z

The pyrenoid is a unique protein complex in the chloroplast stroma of most eukaryotic algae. Schiff(1) has provided some evidence that Euglena pyrenoids contain RuBisCO. Cook et al.(2) reported that the pyrenoid is recognized in the chloroplasts of synchronized cells of E. gracilis only in the first half of the light period. Recently, Kiss et al.(3) showed by immunofluorescence method that anti-spinach RuBisCO binds to the pyrenoid region of the chloroplasts of E. gracilis.