Growth and photosynthetic characteristics of euglena gracilis

Cramer, Marian; Myers, Jack

doi:10.1007/bf00410835

Cited by 520 publications

(194 citation statements)

References 16 publications

Supporting

Mentioning

191

Contrasting

Unclassified

Order By: Relevance

“…1224-5D) were cultivated, either on a mineral medium supplemented with 39 mM lactic acid, as previously described (13), or on a n inorganic salt medium (22), with 1.42 x mM of vitamin B12. Control cells were synchronized in tubes containing 300 ml of Cramer and Myers salt medium at 24"C, with bubbling of mixed air/COa (99/1%).…”

Section: Materials Am) Methodsmentioning

confidence: 99%

DNA flow cytometry of control Euglena and cell cycle blockade of vitamin B12‐starved cells

Lefort‐Tran¹,

Bré²,

Pouphile³

et al. 1987

Cytometry

View full text Add to dashboard Cite

Vitamin B E starvation inIn severe anaemia that is due to B12 avitaminosis, the block of mitosis and the maturation of the erythrocyte line is followed by a diminution of red blood cells, while large cells with abnormal nuclei ~fmegaloblasts") appear in the blood and the bone marrow. These giant cells have a high RNA/DNA ratio (7,26). Defective DNA synthesis in the megaloblastic state has been reviewed (30,40). In vitamin B12-deprived Euglena cells, divisions slow down and then stop, while RNA and protein content, number of chloroplasts, and mitochondria continue to increase (14). For the study of biological and biochemical disorders induced by vitamin B12 deficiency, Euglena cells, whose alterations resemble those observed in the megaloblasts, are a very suitable model for observing where "DNA replication cycle" is decoupled from the "growth cycle" (36), as they are easy to cultivate and even to synchronize. In the recovering cells, after addition of vitamin B12, the DNA replication is completed, followed by cell divisions (9). Two relatively synchronous divisions occur immediately without a new G1 phase (15,32,41).In the model of the metabolic cell cycle block, biochemical analyses have given a mean DNA content of 1.8 or twice that of G1 cells (5,161, with no information on cell heterogeneity. In contrast, microcytofluorometry or flow cytometric analyses can provide data on DNA content of individual cells. These two types of analysis complement each other and can lead to a better understanding of the cell cycle arrest, in light of independent results concerning the dispersed structure of chromatin in starved giant cells (4,6,12), the modification of histones (101, and the nucleosomal organization in control and vitamin B12-starved chromatin (241, all of which could affect DNA stainability.The fluorochrome Hoechst 33258 for DNA labeling was chosen in present studies in order to avoid, as far as possible, nonstoichiometric DNA stainability owing to differences in the conformation of the chromatin (23).Initial studies that used microfluorometry contributed to a better knowledge of the material because individual cells could be observed, and so, for example, mitotic cells could be distinguished from cells in GB. Later, flow cytofluorometric measurements allowed analysis of large samples, and thus statistically more reliable results could be obtained. The data indicated that starved Euglena cells were distributed in the S and G2 phases. No cells were found either in the G1 phase or in the M phase. The unbalanced growth of vitamin B12-deficient cells was characterized by a block in the DNA replication and another block at the transition from G2 to M.The significance of cell arrest is discussed in relation to DNA replication. MATERIALS AM) METHODSControl Cells Euglena gracilis strain Z (Cambridge culture collection No. 1224-5D) were cultivated, either on a mineral

show abstract

Section: Materials Am) Methodsmentioning

confidence: 99%

DNA flow cytometry of control Euglena and cell cycle blockade of vitamin B12‐starved cells

Lefort‐Tran¹,

Bré²,

Pouphile³

et al. 1987

Cytometry

View full text Add to dashboard Cite

show abstract

“…753) was grown in the dark in a heterotrophic medium (Difco Euglena broth) to approximately 3 x lo6 cells/ml. About 2500 ml of the etiolated cell suspension was transferred into 13.5 1 of autotrophic medium [13] and kept at 24-25 "C under 2800 lx of light with continuous aeration for 48 h (ribosome isolation) or 72-96 h (DNA isolation) as previously described [14]. Under these conditions, proplastids develop over a period of approximately 72 -80 h to fully developed and functional chloroplasts without significant cell division [15].…”

Section: Cultivation Of Autotrophic Cellsmentioning

confidence: 99%

The Euglena gracilis Chloroplast Genome:

Kopecká

Crouse

Stutz

1977

European Journal of Biochemistry

View full text Add to dashboard Cite

1. Chloroplast DNA was isolated from autotrophically and mixotrophically grown Euglena gracilis cells.2. Aliquots of chloroplast DNA were mechanically degraded to an average molecular weight of 4-7 x lo6 and G+C-rich DNA fragments (density 1.701 g/cm3) were separated from the bulk DNA (density 1.685 g/cm3) using preparative CsCl density gradients.3. Total chloroplast DNA and its DNA subfractions, which first were characterized with respect to average G + C content and hybridization capacity for chloroplast rRNA, were hydrolysed with restriction endonucleases (endo R . EcoRI, endo R . HindII, endo R . HindIII, endo R . Hind11 +III, endo R . HpaI, endo R . HpaII and endo R . HaeIII). The fragments were separated on gels under a variety of electrophoretic conditions. 4. With each enzyme tested, a rather large number of bands was obtained. In all cases, different banding patterns were obtained for total DNA, and the DNA subfractions.5. Chloroplast DNA from autotrophically and mixotrophically grown cells gave identical banding patterns.6. Digestion of total DNA with the endo R . HaeIII yielded 51 -52 fragments separated in the gels in a total of 36 bands of which 11 -12 bands were composed of 2-3 fragments as estimated by densitometry. The molecular weights of all fragments combined was 87 x lo6 or 95% of the genome (92 x lo6).7. Chloroplast RNA hybridized to 5.1% with total chloroplast DNA, equal to three RNA cistrons per genome ( M , 92 x lo6). These cistrons are located on seven different types of endo R . HaeIII fragments. The hybridising fragments are preferentially found in the G + C-rich subfraction and in bands which are composed of 2-3 fragments.

show abstract

“…A. Schiff, Brandeis University). Cells were grown in a heterotrophic medium [13] modified by using the trace element combination of Cramer and Meyers [ 14]. W3 BUI_ does not contain chDNA [2] yielding, therefore, uncontaminated mtDNA.…”

Section: Isolation and Purification Of Mitochondrial Rnamentioning

confidence: 99%