Changing proportions of DNA components in Euglena gracilis

Gibson, William A.; Hershberger, Charles L.

doi:10.1016/0003-9861(75)90222-2

Cited by 14 publications

(4 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been observed that the buoyant density of this DNA is similar to the chloroplast ribosomal DNA satellite (Nass and Ben-Shaul, 1972). It has also been reported that a chloroplast satellite band increases during logarithmic cultures compared with stationary cultures (Manning and Richards, 1972), and conversely increases when the cells entered stationary phase of growth (Gibson and Hershberger, 1975). These results have led to the speculation that the chloroplast rRNA cistrons are capable of being amplified.…”

Section: Discussionmentioning

confidence: 75%

“…Although it has been recognized that multiple copies of chloroplast DNA are present in Euglena cells (Brawerman and Eisenstadt, 1964;Edelman et al, 1964;Ray and Hanawalt, 1964), and that the chloroplast DNA content varies with the cell growth conditions (Gibson and Hershberger, 1975), quantitative data on the cellular content of chloroplast DNA are limited. Originally the DNA content per Euglena chloroplast was estimated at from 1.2 X 10™15 (Edelman et al, 1964) to 9 X 10-15 g (Brawerman and Eisenstadt, 1964), or between 8 and 60 copies per chloroplast, respectively.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Cellular content of chloroplast DNA and chloroplast ribosomal RNA genes in Euglena gracilis during chloroplast development

Chelm¹,

Hoben²,

Hallick³

1977

Biochemistry

View full text Add to dashboard Cite

The cellular content of chloroplast DNA in Euglena gracilis has been quantitatively determined. DNA was extracted from Euglena cells at various stages of chloroplast development and renatured in the presence of trace amounts of 3H-labeled chloroplast DNA. From the kinetics of renaturation of the 3H-labeled chloroplast DNA, compared with the kinetics of renaturation of excess nonradioactive chloroplast DNA, the fraction of cellular DNA represented by chloroplast DNA was calculated. The content of chloroplast DNA was found to increase from 4.9 to 14.6% of cellular DNA during light-induced chloroplast development. Correcting for the change in DNA mass per cell, the number of copies of chloroplast DNA is found to vary from 1400 to 2900 per cell. During this developmental transition, the cellular content of the chloroplast ribosomal RNA genes varies from 1900 to 5200 copies per cell. The ratio of the number of copies of rRNA genes to chloroplast genomes per cell remains in the range of 1-2 throughout chloroplast development, ruling out selective amplification of chloroplast rRNA genes as a means of regulation of rRNA gene expression. Direct measurement of the number of rRNA cistrons per 9.2 X 10(7) dalton genome yields a value of 1 or 2.

show abstract

Section: Discussionmentioning

confidence: 75%

mentioning

confidence: 99%

Cellular content of chloroplast DNA and chloroplast ribosomal RNA genes in Euglena gracilis during chloroplast development

Chelm¹,

Hoben²,

Hallick³

1977

Biochemistry

View full text Add to dashboard Cite

show abstract

“…Vegetatively reproducing diploid strains of Chlamydomonas have been shown (34) to maintain the same ratio of nuclear to plastid DNA when compared to the normal haploid algal strain. However, given the fact that plastid to nuclear DNA ratios of Euglena may remain the same (15) or change (12,17) One of the most interesting of the many regulatory programs expressed during cell growth is the production and maintenance of a specific organelle complement. A highly refined coordination between plastid biogenesis and cell growth, differentiation, and development must be present to insure the functional efficiency and survival of the cell.…”

Section: Methodsmentioning

confidence: 99%

Variation in Plastid Number

Cattolico¹

1978

Plant Physiol.

View full text Add to dashboard Cite

Changes in the physiological state of the multiplastidic alga OHstbodiscus luteus result in a shift in chloroplast complement from 33 to 21 plastids. The effect of this induced change in organelle complement on nuclear and chloroplast DNA levels has been analyzed. Data suggest that the absolute amount of chloroplast and nuclear DNA found within a cell remains constant but that the amount of chloroplast DNA per plastid is inversely proportional to the number of chloroplasts to which that DNA must be distributed.Eukaryotic cell function is dependent upon a highly refined metabolic coordination between the nucleus and other compartmentalized cellular structures. Of the many organelles present within the cell, chloroplasts probably rank highest in biochemical and structural complexity (6). Light availability (25,30), light quality (23), temperature (25), the presence of plant hormones and specific carbon compounds (4) or the entrance of the organism into a specific differentiation sequence (7) may induce a cell to vary its chloroplast complement significantly. It has been known for some time (1) that nuclear gene products are necessary for organelle maintenance. Recent data (13, 26) obtained by investigators attempting to describe the specific coding function of chloroplast DNA indicate that the per cent chloroplast genome transcribed may change during different phases of cell growth and development. It has been reported (12, 27) that the total amount of chloroplast DNA/cell may shift in response to conditions of cellular maintenance of differentiation. Although a positive correlation has been postulated (8) to exist in higher plant systems between an increase in chloroplast number and a maintenance of nuclear DNA synthesis, little is known of the relationship between plastid number and organelle DNA levels. Feedback loops must exist between the nuclear and organelle genome and the macromolecular communication effected by these loops is, no doubt, of primary importance both in the regulation of organelle development and in the determination of cellular replication.Measurement of the relationship between plastid number, chloroplast DNA complement, and nuclear DNA content should provide background data of critical importance to studies concerned with the elucidation of the macromolecular interaction of genome and plastome in organelle biogenesis.The unicellular alga Olisthodiscus luteus (9) was chosen as the test system for these studies. This organism contains many small plastids which replicate at a defined period of the synchronous cell cycle (9) and plastid

show abstract

“…They found that the plastid DNA content increases from 5 to 14.6% of cellular DNA during chloroplast development. Amplification of parts of chloroplast genome was also reported to occur when a nondividing greening culture was transferred to exponential growth conditions (9,15).…”

mentioning

confidence: 99%

Photomorphogenic Regulation of Chloroplast Replication in Euglena

Srinivas

Lyman²

1980

Plant Physiol.

View full text Add to dashboard Cite

Dark-grown cells of Euglena contain proplastids which, upon exposure to light, differentiate into chloroplasts. During this process, structural and functional changes occur, including the synthesis of pigments, enzymes of photosynthetic electron transport, enzymes of CO2 reduction, chloroplast membrane proteins, and lipids and chloroplast ribosomes (36).Holowinsky and Schiff (17) In addition to the increase of plastid DNA during chloroplast development, Manning and Richards (24) noted that chloroplast DNA undergoes one and one-half rounds of DNA replication per one round of nuclear DNA replication, yet the amount of chloroplast DNA per cell remains constant. They postulated that a mechanism must exist to remove the "extra" DNA. Egan, Dorsky and Schiff (12) reported the light activation of a chloroplast associated DNase. This enzyme was further characterized by Small and Sturgen (40). The action spectrum for the light activation of the nuclease is similar to the action spectrum for the synthesis of Chl and some chloroplast-associated enzymes. Schmidt and Lyman (unpublished data) found that the amount of chloroplast DNA per cell increases in high intensities of blue light. All this evidence suggests the operation of a mechanism to regulate the amount of plastid DNA during chloroplast development as well as during growth. Regulation seems to be operating to keep the amount of chloroplast DNA constant because there is more DNA synthesized per chloroplast division than is needed for merely doubling the DNA content (24).In this paper, we propose that such regulation may occur through a restriction-type nuclease which degrades a fraction of the chloroplast DNA. We also propose that the putative nuclease is activated by the red-blue photomorphogenic system which mediates, with the blue chromophore, chloroplast development.Chloroplast DNA in Euglena constitutes 3 to 5% of the total cellular DNA (39

show abstract

Changing proportions of DNA components in Euglena gracilis

Cited by 14 publications

References 21 publications

Cellular content of chloroplast DNA and chloroplast ribosomal RNA genes in Euglena gracilis during chloroplast development

Cellular content of chloroplast DNA and chloroplast ribosomal RNA genes in Euglena gracilis during chloroplast development

Variation in Plastid Number

Photomorphogenic Regulation of Chloroplast Replication in Euglena

Contact Info

Product

Resources

About