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At least 19 recordsLinked to original sources
PubMed1977

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

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.

Animals↗
PubMed1978

Turnover-synthesis of chloroplast DNA in developing chloroplasts.

The mechanism for the turnover-synthesis of chloroplast DNA in the absence of net synthesis during the chloroplast maturation in Euglena gracilis was determined. DNA synthesis was measured by incorporation of32Pi into chloroplast DNA. The density label, 15N, was incorporated to examine the mechanism of turnover-synthesis. The newly synthesized segments represent a replacement of segments in the DNA containing 1.5 X 10(3) to 6.1 X 10(3) nucleotides. Twenty-three fragments of chloroplast DNA, generated by digestion with the restriction endonuclease EcoRI, became labeled with 32Pi. Turnover-synthesis, therefore, replaces segments throughout the molecule of chloroplast DNA.

Chloroplasts↗
PubMed1978

[Cloning chloroplast DNA in escherichia coli. I. Construction and selection of recombinant plasmids containing fragments of pea chloroplast DNA].

Fragments produced by digestion of Pisum sativum chloroplast DNA with EcoRI were examined by agarose gel electrophoresis. These EcoRI-fragments were joined in vitro to Apr-ColE1 RSF2124 plasmid and cloned in Escherichia coli. Methods of molecular cloning of plasmid chimeras by success gradient centrifugation and repeated transformation and selection of recombinant plasmids using mytomicin C were used for cloning hybrid plasmids with various EcoRI fragments of pea chloroplast DNA has been obtained.

Chloroplasts↗
PubMed1979

[Chloroplast DNA cloning in Escherichia coli. II. The properties of the recombinant plasmids bearing the EcoRI fragments of pea chloroplast DNA and the cloning of the DNA sequences with rRNA genes].

Previously a method of selection of colicine-defective recombinant plasmids by mitomycin C was described. A series of recombinant plasmids (CPS) with various EcoRI-fragments of pea chloroplast DNA has been obtained. This paper describes some properties of cloned fragments replicated in Escherichia coli. The alkali stability of recombinant plasmid DNAs has been demonstrated, indicating the absence of ribonucleotides in their structure. Heterogeneity of chloroplast DNA in nucleotide composition was demonstrated using ultracentrifugation analysis of CPS-plasmid DNAs in CsCl-actinomycin D density gradient. Pea chloroplast rDNA was cloned in recombinant plasmids.

Base Sequence↗
PubMed1979

Fractionation and identification of spinach chloroplast transfer RNAs and mapping of their genes on the restriction map of chloroplast DNA.

Spinach chloroplast 4S RNAs has been separated by two-dimensional polyacrylamide gel electrophoresis into about 35 species. After extraction from the gel, 27 of these RNA species were identified by aminoacylation as tRNAs specific for 16 amino acids. Individual tRNAs were labeled in vitro with 125I and hybridized to DNA fragments obtained by digestion of spinach chloroplast DNA with KpnI, PstI, SalI and XmaI restriction endonucleases. A minimum of 21 genes corresponding to tRNAs for 14 different amino acids have been localized on the restriction endonuclease cleavage site map of the DNA molecule. Of these, 15 genes corresponding to tRNAs for 12 amino acids are located in the larger of the two single-copy regions which separate the two inverted copies of the repeat region. Each copy of this repeat region contains a set of genes for the ribosomal RNAs and a gene for tRNA2Ile in the "spacer" sequence between the 16S and 23S ribosomal RNAs. The genes for tRNA1Ile, tRNA2Leu and tRNA3Leu also map in the repeat region, but outside the ribosomal DNA unit. At present, two more chloroplast tRNAs (for Pro and Lys) have been identified, but not mapped, while 4 unidentified 4S RNAs have been mapped in the large single-copy region of the DNA molecule. Evidence is presented that isoaccepting tRNA species can be transcripts from different loci.

Amino Acyl-tRNA Synthetases↗
PubMed1979

Base composition heterogeneity of Euglena gracilis chloroplast DNA.

Euglena gracilis chloroplast DNA has an average buoyant density of 1.685 gm/cm3, corresponding to 25 mol% G . C base pairs. To test for base compositional heterogeneity within this 130 kilobase pairs (kbp) genome, previously mapped restriction endonuclease fragments were isolated, and characterized by equilibrium buoyant density centrifugation. The chloroplast DNA can be characterized as containing two major buoyant density components. A segment of 17 kbp, representing 13% of the genome and containing the rRNA genes is 43--44 mol% G . C. The remaining 113 kbp, accounting for 87% of the genome, has an average 20--21 mol% G . C content.

Animals↗
PubMed1978

Physical mapping of the ribosomal DNA region of Euglena gracilis chloroplast DNA.

1. The relative positions of endo R . EcoRI and endo R . Bg/II cleavage sites are mapped within the linked DNA fragments Bam-E-E-D of the Euglena gracilis chloroplast DNA. 2. The DNA segment Bam-E-E-D contains three contiguous repeated segments of approximately 5600 base pairs. 3. Each repeated segment can code for an rRNA gene (16-S and 23-S).

Chloroplasts↗
PubMed1979

The association of chloroplast DNA with photosynthetic membrane vesicles from spinach chloroplasts.

To investigate the association between chloroplast DNA (cp DNA) and the photosynthetic membranes of spinach chloroplasts, previously suggested by electron-microscope autoradiography, use has been made of vesicles formed by isolating chloroplasts directly in 3.5 mM Mg2+. These chloroplast vesicles consist of photosynthetic membranes, separate from chloroplast envelope membranes. Light and electron microscopy confirm that the vesicles consist of swollen stroma lamellar membranes with some peripheral grana lamellae that are much less swollen. Vesicles labelled with [H]thymidine were obtained from [3H]thymidine-labelled chloroplasts from spinach disks in which chloroplast division and cp DNA synthesis and segregation were occurring. The chloroplast vesicle fraction retains about 45% of the cp DNA as determined by liquid scintillation counting. The cp DNA-membrane associations do not appear to be dependent on the presence of Mg2+. The chloroplast vesicles can be autoradiographed for light microscopy if they are fixed in formaldehyde and no centrifugation steps are used. Light-microscope autoradiography is consistent with a preferential labelling of grana as opposed to stroma membranes, and long lengths of membrane are labelled. It appears that in spinach chloroplasts cp DNA is associated with granal thylakoids at intervals along the length of a continuous photosynthetic membrane system. Such an organization would facilitate cp DNA segregation during chloroplast division.

Chloroplasts↗
PubMed1979

Isolation of Euglena gracilis chloroplast 5S ribosomal RNA and mapping the 5S rRNA gene on chloroplast DNA.

Ribosomal RNA (5S) from Euglena gracilis chloroplasts was isolated by preparative electrophoresis, labeled in vitro with 125I, and hybridized to restriction nuclease fragments from chloroplast DNA or cloned chloroplast DNA segments. Euglena chloroplast 5S rRNA is encoded in the chloroplast genome. The coding region of 5S rRNA has been positioned within the 5.6 kilobase pair (kbp) repeat which also codes for 16S and 23S rRNA. There are three 5S rRNA genes on the 130-kbp genome. The order of RNAs within a single repeat is 16S-23S-5S. The organization and size of the Euglena chloroplast ribosomal repeat is very similar to the ribosomal RNA operons of Escherichia coli.

Chloroplasts↗
PubMed1977

Restriction endonuclease map of Euglena gracilis chloroplast DNA.

A physical map of the Euglena gracilis chloroplast genome has been constructed, based on cleavage sites of Euglena gracilis chloroplast DNA treated with bacterial restriction endonucleases. Covalently close, circular chloroplast DNA is cleaved by restriction endonuclease SalI into three fragments and by restriction endonuclease BamHI into six fragments. These nine cleavage sites have been ordered by fragment molecular weight analysis, double digestions, partial digestions, and by digestion studies of isolated DNA fragments. A fragment pattern of the products of EcoRI restriction endonuclease digestion of Euglena chloroplast DNA is also described. One of these fragments has been located on the cleavage site map.

Animals↗
PubMed1979

Role of methylation in the modification and restriction of chloroplast DNA in Chlamydomonas.

The different metabolic paths followed by homologous chloroplast DNAs of maternal and paternal origins in zygotes of Chlamydomonas were examined by prelabeling parental cells, before mating them, with [3H]adenine, [3H]thymidine, and [3H]deoxycytidine. Within 6 hr after mating, maternal chloroplast DNA was extensively methylated to 5-methylcytosine and its bouyant density decreased. Paternal chloroplast DNA was largely degraded. Some radioactivity from deoxycytidine of maternal origin reappeared in thymine, and residual paternal DNA contained radioactivity in a base tentatively identified as uracil. These results confirm and extend our previous findings and support our hypothesis that modification (methylation) and restriction enzymes determine maternal inheritance of chloroplast DNA and that the two parental DNAs have different metabolic fates within the zygote.

Adenine↗
PubMed1978

Mapping of transcribed regions of Euglena gracilis chloroplast DNA.

RNA transcription from defined regions of the Euglena gracilis chloroplast genome has been characterized by hybridization of total cell RNA to 3H-labeled chloroplast DNA restriction endonuclease fragments. Chloroplast DNA was digested into five fragments of 53, 35, 25, 10, and 6.9 kilobase pairs (kbp) with Pst1. The 53-kbp DNA was also subfractionated by BamHI digestion. The extent of transcription of the Pst1 fragments was found to be 30, 17, 15, 2.2, and 2.3 kb of RNA, respectively. The total amount of RNA transcription of 67 kb represents 26% to the double-strand information content of the genome. Transcribed regions are dispersed throughout the DNA. The RNA transcripts are present in two major abundance classes in the cell. High abundance transcripts of approximately 10(6) copies/cell were mapped in the rRNA gene region of the 53-kbp fragment and in the 35-kbp fragment. Low abundance transcripts of approximately 1000--4000 copies/cell were mapped in all five Pst fragments.

Animals↗
PubMed1978

The kinetic complexity of Acetabularia chloroplast DNA.

The kinetic complexity of Acetabularia cliftonii chloroplast DNA is 1.52 +/- 0.26 . 10(9) daltons, compared to 0.2 .10(9) daltons for Chlamydomonas chloroplast DNA. There is an average of three genomes per chloroplast. The unusually large size of the Acetabularia genome may reflect the ancient evolutionary history of this organism.

Acetabularia↗
PubMed1979

Use of the fluorochrome 4'6-diamidino-2-phenylindole in genetic and developmental studies of chloroplast DNA.

Use of the DNA-specific fluorochrome 4'6-diamidino-2-phenylindole (DAPI) makes it possible to examine in situ the structure of chloroplast DNA (chDNA) with the fluorescence microscope. This simplifies the study of genetic and developmental changes in chloroplast DNA. Three examples are presented. (a) Wild-type Euglena gracilis B contains several chloroplast DNA nucleoids per chloroplast. A yellow mutant lacking functional chloroplasts is similar, but such nucleoids are absent in an aplastidic mutant strain known from biochemical studies to have lost its chDNA. (b) In vegetative cells of the giant-celled marine algae Acetabularia and Batophora, only about a quarter of the chloroplasts have even one discernible chloroplast DNA particle, and such particles vary in size, showing a 30-fold variation in the amount of DNA-bound DAPI fluorescence detected per chloroplast. By contrast, 98% of chloroplasts in developing Acetabularia cysts contain chDNA, with as many as nine nucleoids per chloroplast. (c) DAPI-stained chloroplasts of chromophyte algae display the peripheral ring of DNA expected from electron microscope studies. However, these rings are not uniform in thickness, but are necklace-like, with the appearance of beads on a string. Since the multiple nucleoids in plastids of chlorophyte algae also appear to be interconnected throughout the chloroplast, a common structural plan may underlie chDNA morphology in both groups of algae.

Acetabularia↗
PubMedDate not supplied

[The character of the distribution of chloroplast DNA from higher plants in a cesium chloride density gradient].

The nature of distribution of the chloroplast DNA from three species of higher plants (Sp. oleracea, N. tabacum, P. sativum) in the CsCl density gradient has been investigated DNA preparations isolated from the fractions of chloroplasts completely deprived of the admixtures of nuclei and mitochondria are characterized by symmetric distribution in the density gradient. Fragmentation of chloroplast DNA of higher plants is not accompanied by the appearance of the discrete satellite components. It has been shown that the satellite DNA component found in the fraction of the unpurified chloroplasts are entirely mitochondrial DNA.

Centrifugation, Density Gradient↗
PubMed1977

Chloroplast DNA distribution in parasexual hybrids as shown by polypeptide composition of fraction I protein.

Sixteen different mature interspecific parasexual hybrids, produced by fusing leaf protoplasts of Nicotiana glauca (G) and N. langsdorffii (L), were analyzed for fraction I protein (ribulose-1,5-bisphosphate carboxylase/oxygenase) which consists of large subunit polypeptides coded by chloroplast DNA and small subunit polypeptides coded by nuclear DNA. All the hybrids showed the combined small subunits of both parents, thus confirming the hybridity of each of the fusion products. Fourteen of the hybrids displayed the large subunit electrofocusing pattern characteristic of only one parent (eight L and six G). From one hybrid callus, two plants were regenerated, of which one had exclusively L-type large subunit and the other had exclusively G. A single plant retained a mixture of L ang G chloroplast DNA's; this later yielded six F2 progeny from one branch, all of which were G type, and three asexual progeny from another branch, all of which had the L-type pattern. In all, 46 F2 progeny and 8 different F3s were analyzed and each of these, with few if any exceptions, showed the same single subunit type as the F1 and F2 parent hybrid plants. Reasons for the rapid sorting out of the chloroplast types are discussed.

Chloroplasts↗