Three-dimensional reconstruction of organelles in Euglena gracilis Z. I. Qualitative and quantitative changes of chloroplasts and mitochondrial reticulum in synchronous photoautotrophic culture

1980 ◽  
Vol 43 (1) ◽  
pp. 137-166
Author(s):  
M. Pellegrini
Keyword(s):  
Cell Cycle ◽  
Cell Volume ◽  
Growth Phase ◽  
Euglena Gracilis ◽  
Light And Electron Microscopy ◽  
Total Cell ◽  
Ultrastructural Changes ◽  
Total Cell Volume ◽  
Euglena Gracilis Z ◽  
Mitochondrial Reticulum

Ultrastructural changes of chloroplasts and mitochondria have been observed in synchronously growing cells of Euglena gracilis Z, under photoautotrophic conditions. Application of the serial section technique allows estimation of the number and volume of these organelles. Several 3-dimensional reconstructions reveal their shape and distribution throughout the cell cycle. In young cells 10 separate diskoid or branched chloroplasts are found. They show the typical lamellar structure of euglenoid chloroplasts. During the growth phase (light period), they enlarge and their volume doubles. Some of them branch out, so that 20 lobes are formed. Thylakoids grow longer without change in number. The pyrenoid persists only during the first half of this period. During the cell division phase (dark period), branched chloroplasts divide along 2 planes which are perpendicular to each other and perpendicular to the thylakoid plane. All thylakoids are cut and their number does not change in the daughter chloroplasts. The plastidome volume constitutes 15–18% of the total cell volume over the entire life cycle. One of the most significant observations in this report is the presence of a single permanent mitochondrial reticulum during the whole cell cycle. This giant mitochondrion consists of an extremely branched network with delicate threads (0.4-0.6 micrometer thick) surrounding the chloroplasts, nucleus and reservoir. It extends throughout the cell. During the growth phase, it becomes gradually longer and doubles in volume. The degree of branching increases but the thickness of the threads remains constant. During the division phase, the mitochondrial elements appear more restricted (0.4 micrometer thick) and the reticulum becomes progressively partitioned into 2 daughter networks. At any time of the cell cycle, the chondriome volume is about 6% of the total cell volume. These results are discussed in comparison with numerous relevant papers on light and electron microscopy of animal and plant cells. They suggest that the descriptions of several authors on the plastidial cycle and the mitochondrial cycle in Euglena, both said to be characterized by alternate reticulate and fragmentary states, arise in part from questionable interpretation of random sections. It is evident that the form and distribution of organelles can be determined more precisely by serial sectioning.

Three-dimensional reconstruction of organelles in Euglena gracilis Z. II. Qualitative and quantitative changes of chloroplasts and mitochondrial reticulum in synchronous cultures during bleaching

1980 ◽  
Vol 46 (1) ◽  
pp. 313-340
Author(s):  
M. Pellegrini
Keyword(s):  
Cell Volume ◽  
Euglena Gracilis ◽  
Sodium Acetate ◽  
Three Dimensional ◽  
Continuous Illumination ◽  
Temperature Cycles ◽  
Giant Mitochondrion ◽  
Successive Generations ◽  
Euglena Gracilis Z ◽  
Mitochondrial Reticulum

By ultrathin serial sectioning, morphological and volumetric changes of the plastidome and chondriome have been observed in Euglena gracilis Z during bleaching in darkness with addition of sodium acetate to the culture medium. In order not to introduce any modification to the synchronization pattern during bleaching, green cells were previously grown photoautotrophically on Cramer & Myers medium under continuous illumination and synchronized by temperature cycles and (2) of sodium acetate and darkness on the plastidome and chondriome of photoautotrophic cells synchronized by light-dark cycles as described previously. In photoautotrophic cells, the plastidome, consisting of about ten diskoidal chloroplasts, occupies 15% of the cell volume. The chondriome, in the form of one single giant mitochondrion branched throughout the cell, represents 6% of the cell volume. The synchronization by temperature cycles in continuous illumination does not change the morphology and volume of these organelles. However, pyrenoids disappear. In photoheterotrophic culture with sodium acetate added, the plastidome fine structure does not vary but its volume decreases by 19–25%. At that time, the plastidome thus occupies 12–13% of the cell volume. Sodium acetate provokes, on the contrary, hypertrophy of the delicate threads of the mitochondrial reticulum which appears as a network with narrow meshes around other organelles. The chondriome thus comes to occupy 10–11% of the cell volume. In heterotrophic cells, the combined effects of sodium acetate and darkness emphasize the regression of the plastidome while the chondriome appears as a fenestrated parietal shell occupying 15–16% of the cell volume. Maximal hypertrophy is obtained in 24 h. Total dedifferentiation of chloroplasts requires 6–9 successive generations in heterotropic conditions. These results are discussed in relation to numerous light-microscopic and ultrastructural observations. It has been demonstrated, as in photoautotrophic Euglena cells synchronized by light-dark cycles, that the plastidome of heterotrophic cells consists of about ten organelles, whereas the chondriome contains one single giant mitochondrion. Contrary to the opinion that the variations of the plastidome and chondriome are reciprocally related, it is proved here that dedifferentiation of chloroplasts and hypertrophy of the chondriome occur at different rates, and may be independent of one another.

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

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.

Needle microepiphytes in a Douglas fir canopy: biomass and distribution patterns

1979 ◽  
Vol 57 (9) ◽  
pp. 1000-1007 ◽  
Author(s):  
George C. Carroll
Keyword(s):  
Cell Volume ◽  
Distribution Patterns ◽  
Douglas Fir ◽  
Total Cell ◽  
Microbial Cell ◽  
Microbial Cells ◽  
Cutting Out ◽  
Total Cell Volume ◽  
Volume Estimates ◽  
Cell Volumes

Distribution patterns and total cell-volume estimates for needle microepiphytes are presented for three strata in the canopy of a single old-growth Douglas fir tree. Microbial cell volume was estimated by photographing transverse sections of needles, tracing microbial profiles on Mylar film, cutting out the tracings, and determining the pooled trace weights from various zones of each needle section. Microbial cells are concentrated in the midrib groove and over the stomatal zones of individual needles. Microbial cell volume on the upper needle surfaces increases during the 1st year and declines in subsequent years. Cell volumes on the lower needle surfaces increase from the 1st to the 3rd year and decrease from the 3rd to the 4th year. An increase in microbial cell volume occurs on both upper and lower surfaces from year 7 to year 8. Total microbial cell volume in relation to available needle surface area is greatest in the lower canopy and decreases with increasing height in the canopy. The total volume of microbial cells on needles was estimated to be 1093 cm3 for the entire tree.

scholarly journals Cellular dimensions affecting the nucleocytoplasmic volume ratio.

1991 ◽  
Vol 115 (4) ◽  
pp. 941-948 ◽  
Author(s):  
J A Swanson ◽  
M Lee ◽  
P E Knapp
Keyword(s):  
Endothelial Cells ◽  
Cell Volume ◽  
Volume Ratio ◽  
Fluorescein Isothiocyanate ◽  
Total Cell ◽  
Nuclear Volume ◽  
Size Exclusion ◽  
Nuclear Surface ◽  
Murine Bone Marrow ◽  
Total Cell Volume

Although it has long been appreciated that larger eukaryotic cells have larger nuclei, little is known about how this size relationship is maintained. Here we describe a method for measuring the aqueous volume ratio of nucleus to cytoplasm, two compartments which are interconnected via the pores in the nuclear envelope. We then use that method to identify proportional cellular dimensions in variously treated cells and in different cell types. Cells were scrape loaded with a mixture of fluorescent dextrans: Texas red dextran, average mol wt = 10,000 (TRDx10), and fluorescein isothiocyanate dextran, average mol wt = 70,000 (FDx70). After introduction into the cytoplasmic space, the TRDx10 distributed into both the nucleus and cytoplasm, whereas the FDx70 was restricted to cytoplasm, due to size exclusion by the nuclear pores. The aqueous nucleocytoplasmic volume ratio (RN/C) was determined by measuring, from fluorescence images of spread cells, total cellular fluorescence of each of the two probes and the fluorescence ratio of those probes in the cytoplasm. RN/C was unaffected by the measurement procedure or by varying temperatures between 23 degrees and 37 degrees C. Loading excess unlabeled dextrans had little effect on RN/C, with the single exception that high concentrations of large dextrans could lower RN/C in endothelial cells. Expanding intracellular membranous compartments of macrophages by phagocytosis of latex beads decreased RN/C. Expanding the same compartment by pinocytosis of sucrose, which nearly doubled total cell volume, had little effect on RN/C, indicating that nuclear volume was more closely linked to the cytoplasmic volume, exclusive of vesicular organelles, than to total cell volume. RN/C was the same in mononucleate and binucleate endothelial cells. Finally, measurements of RN/C in murine bone marrow-derived macrophages, bovine aortic endothelial cells, Swiss 3T3 fibroblasts, PtK2 cells, and CV-1 cells revealed that nuclear volume scaled allometrically with cell volume. The allometric relationship indicated that cell volume was proportional to nuclear surface area.

scholarly journals BLOOD DESTRUCTION DURING EXERCISE

1922 ◽  
Vol 36 (5) ◽  
pp. 481-500 ◽  
Author(s):  
G. O. Broun
Keyword(s):  
Cell Volume ◽  
Plasma Volume ◽  
Peripheral Blood ◽  
Prolonged Exercise ◽  
Jugular Vein ◽  
Total Cell ◽  
Total Cell Volume

The following changes have been demonstrated to take place in the blood of dogs during exercise. 1. An increase in the per cent of cells and hemoglobin in the blood of the jugular vein occurs early in the course of exercise. It probably results from a redistribution of red corpuscles, with an increase in their proportion in the peripheral blood. 2. As exercise is continued, there is a definite increase in plasma volume. 3. A coincident decrease both in the total cell volume and the pigment volume during prolonged exercise suggests that blood destruction then occurs.

Studies on dwarf larvae developed from isolated blastomeres of the starfish, Asterina pectinifera

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 171-185
Author(s):  
Marina Dan-Sohkawa ◽  
Noriyuki Satoh
Keyword(s):  
Cell Volume ◽  
Larval Stage ◽  
Short Range ◽  
Total Cell ◽  
Cell Stage ◽  
Developmental System ◽  
Invertebrate Species ◽  
Total Cell Volume ◽  
Asterina Pectinifera

Not only a whole denuded egg, but also blastomeres isolated from 2-, 4- and 8-cell starfish embryos developed into morphologically normal, but dwarf bipinnariae, the sizes of which were roughly proportionate to that of the respective original blastomeres. Some of the blastomeres isolated from the 16-cell stage were also capable of developing into the larval stage. All isolated blastomeres divided in good synchrony with the control embryos. Blastulae of all groups gastrulated within quite a short range of time, around 14·5 h after insemination at 20±1 °C, although one-third of the 1/8-blastuIa missed this chance but gastrulated by 19·5 h. The number of constituent cells of the 1/8-gastrula was counted to be about 560, which corresponds roughly to one-half that of the 1/4-, one-fourth of the 1/2- and one-eighth of the 1/1-gastrula. This ratio also fitted roughly for the total cell volume. The results are compared with those of other invertebrate species, as well as of some vertebrates, and are discussed in connexion not only with the concepts of ‘regulative’ and ‘mosaic’ eggs, but also with a criterion that does not fit into either of these; the developmental system of the mammals.

The shape of mitochondria and the number of mitochondrial nucleoids during the cell cycle of Euglena gracilis

1989 ◽  
Vol 93 (3) ◽  
pp. 565-570
Author(s):  
YASUKO HAYASHI ◽  
KATSUMI UEDA
Keyword(s):  
Cell Cycle ◽  
Fluorescence Microscopy ◽  
Cell Volume ◽  
Ethidium Bromide ◽  
Euglena Gracilis ◽  
Daughter Cell ◽  
Initial Value ◽  
Daughter Cells ◽  
Total Length ◽  
Mitochondrial Nucleoids

The shape of mitochondria and the number of mitochondrial nucleoids in Euglena cells were examined throughout the cell cycle by fluorescence microscopy. Both photoheterotrophic and heterotrophic cells contained a network of mitochondria that did not divide into fragments at any stage of the cell cycle. Mitochondrial nucleoids could be clearly detected in the mitochondria by staining with ethidium bromide and with DAPI. Half of the mitochondrial nucleoids entered each daughter cell during cytokinesis. Nucleoids in the newly produced daughter cells increased in number as the cells increased in size. The number of nucleoids reached double the initial value in cells at the stage just prior to mitosis. The total length of the mitochondrial net was proportional to the cell volume.

Cell cycle dependent ADP-ribosylation of a unicellular organism, Euglena gracilis Z

1995 ◽  
Vol 111 (2) ◽  
pp. 277-282
Author(s):  
Shigeo Takenaka ◽  
Junko Inagaki ◽  
Shingo Tsuyama ◽  
Kazutaka Miyatake ◽  
Yoshihisa Nakano
Keyword(s):  
Cell Cycle ◽  
Euglena Gracilis ◽  
Unicellular Organism ◽  
Adp Ribosylation ◽  
Cycle Dependent ◽  
Euglena Gracilis Z
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