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Spencer DF, Gray MW. Ribosomal RNA genes in Euglena gracilis mitochondrial DNA: fragmented genes in a seemingly fragmented genome. Mol Genet Genomics 2011; 285:19-31. [PMID: 20978909 DOI: 10.1007/s00438-010-0585-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 10/05/2010] [Indexed: 11/27/2022]
Abstract
Because relatively little information is available about mtDNA in the euglenid protozoa, distant relatives of the kinetoplastid protozoa, we investigated mitochondrial genome structure and expression in Euglena gracilis. We found that isolated E. gracilis mtDNA comprises a heterodisperse collection of short molecules (modal size approximately 4 kbp) and that the mitochondrial large subunit (LSU) and small subunit (SSU) rRNAs are each split into two pieces. For the two halves of the SSU rRNA, we identified separate, non-contiguous coding modules that are flanked by a complex array of (primarily direct) A + T-rich repeats. The potential secondary structure of the bipartite SSU rRNA displays the expected conserved elements implicated in ribosome function. Label from [α-(32)P]GTP was incorporated in the presence of guanylyltransferase into each of the separate SSU and LSU rRNA fragments, confirming that these RNAs are primary transcripts, separately expressed from non-contiguous rRNA modules. In addition to authentic genes for SSU rRNA, we discovered numerous short fragments of protein-coding and rRNA genes dispersed throughout the E. gracilis mitochondrial genome. We propose that antisense transcripts of gene fragments of this type could have been the evolutionary precursors of the guide RNAs that mediate U insertion/deletion editing in the kinetoplastid relatives of the euglenids. To the extent that E. gracilis mtDNA is a representative euglenid mitochondrial genome, it differs radically in structure and organization from that of its kinetoplastid relatives, instead more closely resembling the mitochondrial genome of dinoflagellates in many of its features, an apparent evolutionary convergence.
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Affiliation(s)
- David F Spencer
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, B3H 1X5, Canada
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Charette JM, Gray MW. U3 snoRNA genes are multi-copy and frequently linked to U5 snRNA genes in Euglena gracilis. BMC Genomics 2009; 10:528. [PMID: 19917113 PMCID: PMC2784804 DOI: 10.1186/1471-2164-10-528] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Accepted: 11/16/2009] [Indexed: 11/30/2022] Open
Abstract
Background U3 snoRNA is a box C/D small nucleolar RNA (snoRNA) involved in the processing events that liberate 18S rRNA from the ribosomal RNA precursor (pre-rRNA). Although U3 snoRNA is present in all eukaryotic organisms, most investigations of it have focused on fungi (particularly yeasts), animals and plants. Relatively little is known about U3 snoRNA and its gene(s) in the phylogenetically broad assemblage of protists (mostly unicellular eukaryotes). In the euglenozoon Euglena gracilis, a distant relative of the kinetoplastid protozoa, Southern analysis had previously revealed at least 13 bands hybridizing with U3 snoRNA, suggesting the existence of multiple copies of U3 snoRNA genes. Results Through screening of a λ genomic library and PCR amplification, we recovered 14 U3 snoRNA gene variants, defined by sequence heterogeneities that are mostly located in the U3 3'-stem-loop domain. We identified three different genomic arrangements of Euglena U3 snoRNA genes: i) stand-alone, ii) linked to tRNAArg genes, and iii) linked to a U5 snRNA gene. In arrangement ii), the U3 snoRNA gene is positioned upstream of two identical tRNAArg genes that are convergently transcribed relative to the U3 gene. This scenario is reminiscent of a U3 snoRNA-tRNA gene linkage previously described in trypanosomatids. We document here twelve different U3 snoRNA-U5 snRNA gene arrangements in Euglena; in each case, the U3 gene is linked to a downstream and convergently oriented U5 gene, with the intergenic region differing in length and sequence among the variants. Conclusion The multiple U3 snoRNA-U5 snRNA gene linkages, which cluster into distinct families based on sequence similarities within the intergenic spacer, presumably arose by genome, chromosome, and/or locus duplications. We discuss possible reasons for the existence of the unusually large number of U3 snoRNA genes in the Euglena genome. Variability in the signal intensities of the multiple Southern hybridization bands raises the possibility that Euglena contains a naturally aneuploid chromosome complement.
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Affiliation(s)
- J Michael Charette
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
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Moochhala S, Renton KW. The effect of IFN-alpha-Con1 on hepatic cytochrome P-450 and protein synthesis and degradation in hepatic microsomes. INTERNATIONAL JOURNAL OF IMMUNOPHARMACOLOGY 1991; 13:903-12. [PMID: 1761357 DOI: 10.1016/0192-0561(91)90043-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Interferon and its inducers are well known to depress drug biotransformation in the liver by decreasing the levels of cytochrome P-450 in that organ. We now report that IFN-alpha-Con1, which was constructed from the most frequently observed amino acid sequences in human alpha-interferon subtypes, causes a loss in cytochrome P-450 which could be prevented by pretreating animals with either puromycin or actinomycin D. This suggests that the loss in drug biotransformation is mediated via the production of an intermediate protein. When the turnover of microsomal protein was examined this interferon appeared to depress the synthesis of proteins with molecular weights 46-60 kd and had little effect on the synthesis of other proteins. The in vitro translation of proteins of molecular weights 45-60 kd was also depressed in an in vitro translation system using mRNA isolated from the livers of interferon treated hamsters. Interferon had no effect on the degradation of microsomal proteins of all molecular weights. It is concluded that interferon probably depresses the levels of cytochrome P-450 in the liver by decreasing the synthesis of the apoprotein and that interferon has little effect on the degradation of the hemoprotein.
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Affiliation(s)
- S Moochhala
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
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Toledo HÃ, Jerez CA. In vivo and in vitro methylation of the elongation factor EF-Tu fromEuglena gracilischloroplast. FEMS Microbiol Lett 1990. [DOI: 10.1111/j.1574-6968.1990.tb03830.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Abstract
We have previously shown that a sulphate activating system is present on the outside of the inner mitochondrial membrane of Euglena gracilis Klebs. var. bacillaris Cori, but efforts to couple this system to ATP produced from oxidative phosphorylation were unsuccessful. In the present work we show that the concentration of Pi ordinarily used to support oxidative phosphorylation in these mitochondria (10 mM) inhibits sulphate activation completely; by reducing the concentration of Pi 10-fold, both processes proceeded normally. Sulphate activation under these conditions is inhibited nearly completely by the uncouplers of oxidative phosphorylation dinitrophenol (0.1 mM) and carbonyl cyanide m-chlorophenylhydrazone (CCCP) (0.2 microM). Sulphate reduction to form free cysteine, most of which appears outside the organelle, and in the cysteine of mitochondrial protein can be demonstrated in the same preparations, is membrane-bound and is inhibited by chloramphenicol (100 micrograms/ml), NaN3 (5 mM), KCN (100 microM); dinitrophenol (0.1 mM) or CCCP (0.2 microM). Digitonin fractionation of the mitochondria into mitoplasts, outer membranes and an intermembrane fraction show that reduction of 35SO4(2-) to form free cysteine and cysteine of protein is located on the mitoplasts; adenosine 5'-phosphosulphate sulphotransferase, the first enzyme of sulphate reduction, is found in the same location. Sulphate activation is highly enriched in the mitochondrial fraction of Euglena; the small amount found in the chloroplast fraction can be attributed to mitochondrial contamination. Thus, in Euglena, sulphate activation and reduction are contained in a sulphate metabolizing centre on the outside of the mitochondrial inner membrane; this centre appears to supply the mitochondrion and the rest of the cell with the products of sulphate activation as well as with reduced sulphur in the form of cysteine. Mitochondria from wild-type Euglena cells and from W10BSmL, a mutant lacking plastids completely, appear to be similar in the properties studied.
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Affiliation(s)
- T Saidha
- Biology Department, Brandies University, Waltham, MA 02254
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Bouet C, Schantz R, Dubertret G, Pineau B, Ledoigt G. Translational regulation of protein synthesis during light-induced chloroplast development in Euglena. PLANTA 1986; 167:511-520. [PMID: 24240367 DOI: 10.1007/bf00391227] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/1985] [Accepted: 10/24/1985] [Indexed: 06/02/2023]
Abstract
Control of gene expression in Euglena was examined during light-induced chloroplast development. Greening was achieved under standard conditions which allowed the synthesis of all plastid proteins in both cytoplasmic and chloroplastic compartments, or under experimentally modified conditions inducing the preferential synthesis of the photosystem II (PSII) light-harvesting antenna or reaction centers. The relative composition of total mRNAs in cellular, cytoplasmic or chloroplastic fractions, as analyzed by their in-vitro translation products in cell-free systems did not significantly change during the in-vivo protein-synthesis processes which are specific to each greening system. By contrast, cytoplasmic polysomal mRNAs extracted during the selective recovery phase of PSII light-harvesting antennae provided a major in-vitro synthesis product of 28 kDa which could correspond to a precursor of the main 26-kDa apoprotein of the light-harvesting chlorophyll a/b protein complex. Similarly, the in-vivo selective synthesis of the 41-kDa and 51-kDa polypeptides of PSII reaction centers was concomitant with an enrichment of plastid polysomes in mRNA species coding for polypeptides of the same molecular weight. These observations confirm that protein synthesis during chloroplast development in Euglena is weakly regulated at the transcription level and they demonstrate that translational regulation occurs in both the cytoplasmic and the chloroplastic compartments.
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Affiliation(s)
- C Bouet
- Laboratoire de Cytophysiologie de la Photosynthèse, C.N.R.S., F-91190, Gif sur Yvette, France
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Gómez-Silva B, Schiff JA. Synthetic abilities of Euglena chloroplasts in darkness. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 808:448-54. [PMID: 3925991 DOI: 10.1016/0005-2728(85)90153-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Protein synthesis, normally a light-dependent process in isolated mature chloroplasts of Euglena gracilis var. bacillaris will take place in darkness if ATP and Mg2+ (ATP/Mg) are supplied. Either 5 or 10 mM ATP plus 15 mM MgCl2 are optimal and rates equal to those in the light can be obtained. Since ATP and Mg2+ are not stoichiometrically related, and since the optimal Mg2+ concentration is similar to that which stabilizes chloroplast ribosomes in vitro, it is suggested that the chloroplast is freely permeable to Mg2+ under these conditions. Protein synthesis under these conditions is not inhibited appreciably by DCMU, FCCP, cycloheximide, or by the addition of ribonuclease, but is highly sensitive to chloramphenicol. Carbon dioxide fixation is also a light-dependent process in isolated mature chloroplasts from Euglena, but addition of ATP (5 mM) and fructose bisphosphate (5 mM) plus aldolase (1.0 unit/ml) (fructose-1,6-bisphosphate/aldolase) yields CO2 fixation rates in darkness that are 43% of those normally obtained in the light. Mg2+ higher than 1.0 mM (e.g., 16 mM) is somewhat inhibitory. Chlorophyll synthesis from 5-aminolevulinate in 36 h developing chloroplasts from Euglena is also light-dependent, but addition of ATP/Mg and fructose-1,6-bis-phosphate/aldolase in darkness brings about the accumulation of a compound having the same RF on chromatography as protochlorophyllide from Barley; a subsequent brief illumination of the chloroplasts converts this compound to a compound with the RF of chlorophyll. Thus Euglena chloroplasts supplied with appropriate additions can carry out protein synthesis, carbon dioxide fixation and most of chlorophyll synthesis in darkness. This versatility is appropriate in photosynthetic organelles isolated from photo-organotrophic cells.
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Alhadeff M, Schiff JA. REGULATION OF PROTOCHLOROPHYLL(IDE) LEVELS IN DARK-GROWN NON-DIVIDING Euglena—II. INFLUENCE OF UTILIZABLE SUBSTRATES AND INHIBITORS OF PROTEIN SYNTHESIS. Photochem Photobiol 1983. [DOI: 10.1111/j.1751-1097.1983.tb03601.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Structural differences between ribosomes of various eukaryotes: stability, density, mass, size and structure in solution of cytoplasmic ribosomes from Tetrahumena, Artemia and Euglena. Int J Biol Macromol 1983. [DOI: 10.1016/0141-8130(83)90061-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Skowronski GA, Garrigan OW. Glycolipids and thylakoid proteins in chloroplasts and streptomycin-bleached lamellae ofEuglena. Lipids 1983. [DOI: 10.1007/bf02535394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Pineau B. Biosynthesis of ribulose-1.5-bisphosphate carboxylase in greening cells of Euglena gracilis : The accumulation of ribulose-1.5-bisphosphate carboxylase and of its subunits. PLANTA 1982; 156:117-128. [PMID: 24272307 DOI: 10.1007/bf00395426] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/1982] [Accepted: 07/01/1982] [Indexed: 06/02/2023]
Abstract
Light induction of chloroplast development in Euglena leads to quantitative changes in the protein composition of the soluble cell part. One major part of these is the observed accumulation of ribulose-1.5-bisphosphate carboxylase/oxygenase (RuBPCase) enzyme (EC 4.1.1.39). As measured by immunoelectrophoresis, a small amount of RuBPCase (about 10(-6) pmol) is present in a dark-grown cell, whereas a greening cell (72h) contains 10-20 pmol enzyme. Both the cytoplasmic and chloroplastic translation inhibitors, cycloheximide and spectinomycin, have a strong inhibitory effect on the synthesis of the enzyme throughout the greening process of Euglena cells. Electrophoretic and immunological analyses of the soluble phase prepared from etiolated or greening cells do not show the presence of free subunits of the enzyme. For each antibiotic-treated greening cell, the syntheses of both subunits are blocked. Our data indicate that tight reciprocal control between the syntheses of the two classes of subunits occurs in Euglena. In particular, the RuBPCase small subunit synthesis in greening Euglena seems more dependent on the protein synthesis activity of the chloroplast than the syntheses of other stromal proteins from cytoplasmic origin.
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Affiliation(s)
- B Pineau
- Cytophysiologie de la Photosynthèse, CNRS, F-91190, Gif-sur-Yvette, France
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James L, Schwartzbach S. Differential regulation of phosphoglycolate and phosphoglycerate phosphatases in Euglena. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/0304-4211(82)90151-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Tsushimoto G, Kikuchi T, Ishida MR. Recovery from inhibition of transcription in gamma-irradiated Euglena cells. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 697:14-9. [PMID: 6805513 DOI: 10.1016/0167-4781(82)90039-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
1. Transcriptional activity was inhibited with low doses of gamma-irradiation which did not cause the death of cells, but induced the delay of cell division in the unicellular alga Euglena. 2. The incorporation of [14C]uracil into cells was inhibited to about 50% of non-irradiated cells immediately after 3 krad irradiation. 3. The suppressed transcriptional activity was gradually recovered after irradiation. At about 12 h post-irradiation, the rate of incorporation of [14C]uracil recovered to that of non-irradiation cells. 4. The synthesis of ribosomal RNA was inhibited immediately after 3 krad irradiation, but it was recovered within 12 h after irradiation. The synthesis of cytosol ribosomal RNA precursor was more strongly inhibited than that of other cytosol ribosomal RNAs. 5. The synthesis of cytoplasmic organelle ribosomal RNA was also inhibited and recovered after 3 krad irradiation.
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PHOTOCONTROL OF CHLOROPLAST DEVELOPMENT IN EUGLENA. Physiology (Bethesda) 1982. [DOI: 10.1016/b978-0-12-139903-0.50015-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2023] Open
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Pfisterer J, Buetow DE. In vitro reconstruction of the mitochondrial translation system of yeast. Proc Natl Acad Sci U S A 1981; 78:4917-21. [PMID: 6946437 PMCID: PMC320294 DOI: 10.1073/pnas.78.8.4917] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We have isolated the translation system from yeast mitochondria and have reconstructed it in vitro. This submitochondrial system, composed of mitochondrial ribosomes, tRNA, pH 5 fraction and mRNA, is maximally active at 10 mM Mg2+ and 100 mM KCl or NH4Cl. NH4+ is more stimulatory than K+. Added Escherichia coli tRNA gives less than half the activity obtained with added mitochondrial tRNA. Activity is enhanced with protease inhibitors but not with Ca2+, spermine, or spermidine. In contrast to heterologous translation systems, the present system produces products with molecular weights similar to those of products synthesized by yeast mitochondria in vivo and by intact yeast mitochondria in vitro. The results support the idea that the unique coding features of the mitochondrial genome require a unique translation system for accurate translation of mitochondrial mRNAs.
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Wurtz EA, Buetow DE. Intraspecific variation in the structural organization and redundancy of chloroplast ribosomal DNA cistrons in Euglena gracilis. Curr Genet 1981; 3:181-7. [DOI: 10.1007/bf00429820] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/1981] [Indexed: 10/26/2022]
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Gilbert CW, Buetow DE. Gel Electrophoresis of Chloroplast Polypeptides: Comparison of One-Dimensional and Two-Dimensional Gel Analyses of Chloroplast Polypeptides From Euglena gracilis. PLANT PHYSIOLOGY 1981; 67:623-8. [PMID: 16661726 PMCID: PMC425744 DOI: 10.1104/pp.67.4.623] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Euglena chloroplast polypeptides are resolved by an adaptation of the two-dimensional gel electrophoretic technique of O'Farrell (1975 J Biol Chem 250: 4007-4021). The present results are compared with those obtained by our earlier two-dimensional gel analyses as well as those obtained by one-dimensional gel analyses. Up to 75 micrograms of Euglena chloroplast polypeptides are resolved on one-dimensional sodium dodecylsulfate linear gradient 7.5 to 15% polyacrylamide gels into 43 stained polypeptide bands compared to only 33 bands resolved on a similar gel containing only 10% polyacrylamide. In contrast, two-dimensional gel electrophoresis (isoelectric focusing for the first dimension, sodium dodecylsulfate gel electrophoresis for the second dimension) further improves the resolution of the chloroplast polypeptides and especially so when a linear gradient gel is used for the second dimension. Delipidation of Euglena chloroplasts with acetone-ether and subsequent solubilization of polypeptides with Triton X-100 followed by sonication are all necessary for successful resolution of chloroplast polypeptides on two-dimensional gels. Up to 300 micrograms of chloroplast polypeptides can be clearly resolved into 56 to 59 stainable spots by the present two-dimensional gel technique when a linear gradient gel is used for the second dimension. Thus, about 30% of the polypeptide bands on a one-dimensional gel are separated into multiple polypeptides on a two-dimensional gel. The use of two-dimensional gels to separate labeled polypeptides with subsequent detection of labeled spots by autoradiography or fluorography again improves the resolution of the chloroplast polypeptides. For example, when (35)S-labeled chloroplast polypeptides are separated by the present two-dimensional gel technique with a linear gradient polyacrylamide gel in the second dimension, autoradiography or fluorography detects over 80 individual polypeptide spots. This is about twice the number resolved by our previous analyses which used a 10% polyacrylamide gel in the second dimension. Polypeptides detected range in molecular weight from about 8.5 to about 145 kilodaltons with apparent isoelectric points from pH 4.5 to 8.0. Fluorography provides rapid detection of labeled polypeptides and is 10 times more sensitive than autoradiography.
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Affiliation(s)
- C W Gilbert
- Department of Physiology and Biophysics, University of Illinois, Urbana, Illinois 61801
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Dubertret G, Ambard-Bretteville F. Functional and Structural Organization of Chlorophyll in the Developing Photosynthetic Membranes of Euglena gracilis Z: II. CHARACTERISTICS OF THE LATE FORMATION OF ACTIVE PHOTOSYSTEM II REACTION CENTERS DURING FIRST STAGES OF GREENING. PLANT PHYSIOLOGY 1981; 67:47-53. [PMID: 16661631 PMCID: PMC425619 DOI: 10.1104/pp.67.1.47] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
During light-induced greening of dark-grown, nondividing Euglena gracilis Z, there is a delay of about 10 hours in the formation of active photosystem II (PSII) reaction centers compared to chlorophyll synthesis. Experiments with greening under different light intensities rule out the possibility that this delay results from a late induction of active PSII reaction center formation when a definite amount of chlorophyll is attained in the early greened cells. Experiments on greening after preillumination show that this delay does not originate in a long, light-induced formation of specific synthesizing machinery for reaction center components. Experiments with greening in the presence of streptomycin show that, when this inhibitor of protein synthesis by chloroplastic ribosomes is added to dark-grown, preilluminated cells or to cells already greened for 24 hours, the formation of active PSII reaction centers is inhibited after a time which depends on the light intensity used for greening. Under very low light intensity (150 lux), the addition of streptomycin to 24-hour greened cells does not prevent further development of functional chloroplasts. These observations lead to the conclusion that streptomycin-insensitive chloro-plast development occurs due to syntheses of cytoplasmic origin and of light-induced pools of components synthesized early by chloroplastic ribo-somes. Conformational changes requiring time may allow the insertion of components necessary for the reorganization of PSII reaction centers in the developing thylakoid after synthesis. This hypothesis accounts for the observed delay in PSII reaction center formation compared to chlorophyll synthesis.
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Affiliation(s)
- G Dubertret
- Cytophysiologie de la Photosynthèse, Centre National de la Recherche Scientifique, Gif sur Yvette, France, 91190
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Dubertret G, Ambard-Bretteville F. Functional and Structural Organization of Chlorophyll in the Developing Photosynthetic Membranes of Euglena gracilis Z: III. SEQUENCE OF EVENTS LEADING TO THE FORMATION OF FUNCTIONAL PHOTOSYSTEM II PHOTOSYNTHETIC UNITS. PLANT PHYSIOLOGY 1981; 67:54-8. [PMID: 16661633 PMCID: PMC425620 DOI: 10.1104/pp.67.1.54] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Greening cells of Euglena were transferred back to darkness at different stages of chloroplast development in the presence or absence of specific inhibitors of protein synthesis. The analysis of chloroplast components showed that: (a) cycloheximide or streptomycin does not significantly inhibit the formation in darkness of active photosystem II (PSII) reaction centers if added after the lag phase for chloroplast development; (b) a limited number of active reaction centers are formed in the dark, sufficient to increase PSII reaction center to chlorophyll ratios to values close to those found in fully greened cells; (c) these dark-formed reaction centers appear to be inserted in already constituted and complete light-harvesting antennae. These results complement previous ones and lead us to propose a model for a sequential formation of PSII photosynthetic units during greening of Euglena, whereby conformational changes requiring time would allow already synthesized components of PSII reaction centers to be inserted or reorganized as active photochemical complexes in association with previously formed light-harvesting antennae.
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Affiliation(s)
- G Dubertret
- Cytophysiologie de la Photosynthèse, Centre National de la Recherche Scientifique, Gif sur Yvette, France, 91190
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Aroskar VA, Watt RA, Emeh JK, Niranjan BG, Biunno I, Avadhani NG. Polysome-dependent in vitro translation system capable of peptide chain reinitiation. Biochemistry 1980; 19:6105-11. [PMID: 7470453 DOI: 10.1021/bi00567a024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A sensitive in vitro translation system has been developed which makes use of cellular polysomes as the source of mRNA and ribosomes. The soluble factors are derived from the preincubated S-30 fraction by centrifugation through a discontinuous sucrose gradient. Of the four fractions tested, fraction 1 (topmost fraction in the gradient) and fraction 2 (fraction sedimenting in 0.5 M sucrose) were stimulatory. These two fractions together yield the highest activity, corresponding to about 125 times the background incorporation. The polysome-directed system exhibits optimal activity in the range 1.8-2 mM Mg2+ and 125-175 mM KCl. The polysome-directed in vitro products exhibit a complexity comparable to the in vivo products resolved on the two-dimensional polyacrylamide gels of O'Farrell [O'Farrell, P. (1975) J. Biol. Chem. 250, 4007-4021]. The system is capable of active chain reinitiation as indicated by partial inhibition by 7-methylguanosine 5'-monophosphate and pactomycin and N-terminal end analysis of in vitro products. This system can also translate polysomes from diverse tissues such as mouse liver, rat liver, and rat brain. The levels and also the authenticity of translation of rat liver albumin and mouse liver carbamoyl phosphate synthetase I were tested by immunoprecipitation with monospecific antibodies. The results show that the major as well as the minor translation products are synthesized in this system at levels comparable to the physiological levels.
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Graves MC, Breitenberger CA, Spremulli LL. Euglena gracilis chloroplast ribosomes: improved isolation procedure and comparison of elongation factor specificity with prokaryotic and eukaryotic ribosomes. Arch Biochem Biophys 1980; 204:444-54. [PMID: 6778393 DOI: 10.1016/0003-9861(80)90055-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Milner JJ, Hershberger CL. Euglena gracilis Chloroplast DNA Codes for Polyadenylated RNA. PLANT PHYSIOLOGY 1979; 64:818-21. [PMID: 16661061 PMCID: PMC543370 DOI: 10.1104/pp.64.5.818] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Polyadenylated RNA, isolated from total cellular RNA of photoautotrophically grown Euglena gracilis, comprised 2.1% of the total cellular RNA and contained 6.2% polyadenylic acid. Polyadenylated RNA, labeled in vitro with (125)I, hybridized at saturating levels to an average 7.7% of the chloroplast DNA. In the presence of excess chloroplast rRNA, hybridization of polyadenylated RNA was reduced, but was still observed at a level corresponding to 2.8% of the chloroplast DNA. Polyadenylic acid was not detected in mRNA prepared from chloroplast polyribosomes, indicating a level of less than 0.1% polyadenylic acid in mature chloroplast mRNA. Of the total RNA isolated from cytoplasmic polyribosomes, 2.0% contained polyadenylic acid. This latter polyadenylated RNA did not hybridize to chloroplast DNA.
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Affiliation(s)
- J J Milner
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801
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Bingham S, Schiff JA. Events surrounding the early development of Euglena chloroplasts. 16. Plastid thylakoid polypeptides during greening. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 547:531-43. [PMID: 114219 DOI: 10.1016/0005-2728(79)90032-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Using sulfolipid to locate plastid thylakoid membranes in gradients from dark-grown resting cells it has been possible to study the plastid thylakoid membrane polypeptides of Euglena gracilis var. bacillaris undergoing light-induced chloroplast development. All plastid thylakoid bands seen in dark-growing wild-type cells and in mutant W3BUL in which plastid DNA is undetectable, are observed to increase in amount during plastid development. Others, which are undetectable in dark-grown wild-type and W3BUL increase greatly during plastid development and appear to be those associated with pigment-protein complexes. The data obtained from experiments where the polypeptides were labeled with 35S during development, either continuously or in pulses, were consistent with these findings. Cycloheximide strongly inhibited the increases in amount in all bands and chloramphenicol or streptomycin produced a lower level of inhibition in all bands indicating tight control of theformation of each plastid membrane constituent by the others. The formation of a polypeptide band of 25 000 molecular weight, thought to be a part of a pigment-protein complex of the thylakoid, and chlorophyll synthesis were inhibited identically by these antibiotics.
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24
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Smith BA, Burke DD. Evidence for the presence of messenger ribonucleic acid in Allomyces macrogynus mitospores. J Bacteriol 1979; 138:535-41. [PMID: 571435 PMCID: PMC218210 DOI: 10.1128/jb.138.2.535-541.1979] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Sucrose density gradient analysis was used to show that polysomes were present in the mitospores of Allomyces macrogynus. Fifty percent of the spore monosomes were shown to be resistant to dissociation by 0.8 M KCl, indicating that messenger ribonucleic acid (mRNA) was bound to them. These polysomes and all the spore ribosomes were contained in the nuclear cap. Only 4S RNA could be demonstrated in the extra-cap fraction. Hybridization studies using 3H-labeled polydeoxythymidylic acid indicated that polyadenylate was present to the extent of 0.08% of the total spore RNA. Sixty-eight percent of the polyadenylic acid is found in the nuclear cap, and 32% is found in the extra-cap fraction. It was demonstrated that [3H]uridine was taken up by the spores and converted to uridine triphosphate. Lack of incorporation of 3H into RNA indicated that the spores do not synthesize RNA. Thus, the mRNA found in spores is synthesized prior to spore formation.
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25
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Freyssinet G, Harris GC, Nasatir M, Schiff JA. Events Surrounding the Early Development of Euglena Chloroplasts: 14. Biosynthesis of Cytochrome c-552 in Wild Type and Mutant Cells. PLANT PHYSIOLOGY 1979; 63:908-15. [PMID: 16660836 PMCID: PMC542943 DOI: 10.1104/pp.63.5.908] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Lack of a suitable assay has thwarted attempts to measure cytochrome c-552 in dark-grown wild type cells of Euglena gracilis var. bacillaris in mutants and in other situations where the concentrations are low. Purification methods are described based on electrofocusing which provide a cytochrome c-552 preparation homogeneous enough to elicit a single reactive antibody in rabbits; this antibody is then used as a specific and sensitive assay for cytochrome c-552. Dark-grown cells of wild type and of mutants O(1)BS, O(2)BX, G(1)BU and P(1)BXL (which make normal sized chloroplasts with abnormal internal structure in the light) have 0.02 to 0.1 x 10(-11) micromoles of cytochrome c-552 per cell, 10 to 150 times less than light-grown cells. Light-grown cells of these mutants and of wild type show a ratio of chlorophyll to cytochrome of about 300 (mole to mole). Cytochrome c-552 is undetectable in dark-grown Y(1)BXD, Y(3)BUD, and W(34)ZUD which cannot carry plastid development beyond the proplastid in light; the light-grown cells of these mutants have levels of cytochrome similar to or lower than dark-grown wild type cells. Cytochrome c-552 is undetectable in light- and dark-grown mutants in which plastid DNA is undetectable (such as Y(2)BUL, W(3)BUL, W(8)BHL, and W(10)BSmL) consistent with the view, but not proving, that this molecule may be coded, at least in part, in plastid DNA. During light-induced chloroplast development in resting cells, cytochrome c-552 formation behaves in all respects like chlorophyll except that the dark-grown cells contain low amounts of the cytochrome c-552 but lack chlorophyll. Thus, both cytochrome c-552 and chlorophyll show the same lag period even when the length is changed by nutritional manipulation; preillumination largely eliminates the lag in the formation of both molecules, cycloheximide and streptomycin both inhibit the biosynthesis of chlorophyll and cytochrome c-552 in the same manner, and the formation of both during chloroplast development is strictly light-dependent. It is shown that chloroplasts isolated from Euglena by methods thought to give intact organelles, lack 95% of the cytochrome c-552; this and the loss of similar molecules may explain why these isolated chloroplasts are not photosynthetically active.
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Affiliation(s)
- G Freyssinet
- Institute for Photobiology of Cells and Organelles, Brandeis University, Waltham, Massachusetts 02154
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26
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Dockerty A, Merrett MJ. Isolation and enzymic characterization of euglena proplastids. PLANT PHYSIOLOGY 1979; 63:468-73. [PMID: 16660749 PMCID: PMC542852 DOI: 10.1104/pp.63.3.468] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Organelles were isolated from dark-grown Euglena gracilis Klebs by sucrose density gradient centrifugation. Plastids, identified by triosephosphate isomerase and NADP glyoxylate reductase were present at an equilibrium density of 1.24 grams per cubic centimeter clearly separated from mitochondria at an equilibrium density of 1.22 grams per cubic centimeter. Assay for choline phosphotransferase and glucose-6-phosphatase showed that endoplasmic reticulum membranes were present at a density of 1.12 grams per cubic centimeter. The plastid fraction contained phosphofructokinase, pyruvate kinase, triosephosphate isomerase and aldolase indicating the operation of a glycolytic pathway. During regreening pyruvate kinase and phosphofructokinase in the developing proplastid decreased, neither enzyme being present in the mature chloroplast. However, plastids were present in the photosynthetic cell as shown by a peak of glycolysis enzymes at an equilibrium density of 1.24 grams per cubic centimeter.The integrity of isolated plastids was demonstrated by their capacity for protein synthesis. Plastids isolated from dark-grown cells rapidly incorporated [(35)S]methionine into protein with an absolute dependence on added ATP. The large subunit of ribulose diphosphate carboxylase was the major polypeptide synthesized by these isolated plastids.
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Affiliation(s)
- A Dockerty
- Postgraduate School of Studies in Biological Sciences, University of Bradford, Yorkshire BD7 1DP England
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27
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28
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29
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Slavik NS, Widholm JM. Inhibition of deoxyribonuclease activity in the medium surrounding plant protoplasts. PLANT PHYSIOLOGY 1978; 62:272-5. [PMID: 16660499 PMCID: PMC1092103 DOI: 10.1104/pp.62.2.272] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
After 1 hour, exogenous deoxyribonucleic acid was degraded within a culture medium at 25 C (pH 6) containing protoplasts of Daucus carota L. var. sativa. Low temperature incubation (1 C) or the addition of 45 millimolar sodium citrate to the medium eliminated DNase activity for at least 4.5 hours. This DNase activity was not reduced at pH 7 or 9, nor by addition of 200 millimolar adenosine 5'-triphosphate.Techniques were developed to ensure high protoplast plating efficiencies and high regenerative capabilities after low temperature treatment and the addition of sodium citrate to the medium. Results indicated citrate concentrations to 45 mm and 1 C temperatures revealed little or no effect on protoplast regeneration capacities. Protoplast viability was 90 to 95% at the time of plating as determined by phenosafranin staining and an estimated 50 to 60% of these undergo cell division in the solid agar medium.
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Affiliation(s)
- N S Slavik
- Department of Agronomy, University of Illinois, Urbana, Illinois 61801
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30
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Freyssinet G. Determination of the site of synthesis of some Euglena cytoplasmic and chloroplast ribosomal proteins. Exp Cell Res 1978; 115:207-19. [PMID: 98335 DOI: 10.1016/0014-4827(78)90418-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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31
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Zielinski RE, Price CA. Relative Requirements for Magnesium of Protein and Chlorophyll Synthesis in Euglena gracilis. PLANT PHYSIOLOGY 1978; 61:624-5. [PMID: 16660349 PMCID: PMC1091930 DOI: 10.1104/pp.61.4.624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The relationships among Mg, growth, chlorophyll synthesis, and cytoplasmic polysome content were studied in Euglena gracilis grown in different levels of the metal. At all levels of magnesium from 20 to 1,600 mumolar, both protein and chlorophyll are formed with exponential kinetics. The apparent rates of synthesis and final yields of both components are greater at higher levels of Mg, but the rate of chlorophyll synthesis always exceeds the rate of protein formation; i.e. the most severely deficient cells contain proportionally more chlorophyll than the sufficient cells. Cytoplasmic polysomes isolated from Mg-deficient Euglena are indistinguishable from those isolated from control cells. We conclude that decreased rates of protein synthesis occur prior to and possibly are causal to decreased rates of chlorophyll synthesis, but that the mechanism of this inhibition remains unclear.
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Affiliation(s)
- R E Zielinski
- Waksman Institute of Microbiology, Rutgers University, P.O. Box 759, Piscataway, New Jersey 08854
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32
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Nigon V, Heizmann P. Morphology, Biochemistry, and Genetics of Plastid Development in Euglena gracilis. INTERNATIONAL REVIEW OF CYTOLOGY 1978. [DOI: 10.1016/s0074-7696(08)62243-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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33
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34
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Azad AA. Cytoplasmic RNA from hen reticulocytes, mouse sarcoma 180 ascites cells, rat liver and barley embryos. Their preparation and purification by a standard procedure and characterization by polyacrylamide gel electrophoresis. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1978; 61:213-8. [PMID: 95685 DOI: 10.1016/0305-0491(78)90163-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
1. This paper describes a standard procedure for the preparation and purification of RNA from the post-mitochondrial supernatants of a number of eukaryotes. 2. Cytoplasmic RNA was fractionated by NaCl precipitation. The 28S (26S), 18S and 5.8S rRNA, and 9S RNA, in the NaCl insoluble fraction were separated by a two-step sucrose gradient fractionation procedure. Poly(A)-containing mRNA in hen 9S RNA was purified by affinity chromatography. The 5S rRNA and tRNA in the NaCl-soluble fraction were fractionated by gel filtration. 3. Polyacrylamide gel electrophoresis showed that the above RNA species were remarkably stable and homogeneous. Differences were found in the 26-28S rRNA, 5.8S rRNA, and 9S RNA of different eukaryotes, but other cytoplasmic RNA species were identical.
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Affiliation(s)
- A A Azad
- Molecular Biology Unit, Research School of Biological Sciences, Australian National University, Canberra
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35
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Abstract
Active cytoplasmic ribosone subunits 41 and 62S were prepared by treatment with 0.1 mM puromycin in the presence of 265 mM KCl. Active chloroplast subunits 32 and 49S were obtained after dialysis of chloroplast ribosomal preparations against 1 mM Mg(2+)-containing buffer. Proteins from these different ribosomal particles were mapped by two-dimensional gel electrophoresis in the presence of urea. The 41S small cytoplasmic ribosomal subunit contains 33-36 proteins, the 62S large cytoplasmic ribosomal subunit contains 37-43, the 32S small chloroplast ribosomal subunit contains 22-24, and the 49ts large chloroplast ribosomal subunit contains 30-34 proteins. Since some proteins are lost during dissociation of monosomes into subunits, the 89S cytoplasmic monosome would have 73-83 proteins and the 68S chloroplast monosome, 56-60. The amino acid composition of ribosomal proteins shows differences between chloroplast and cytoplasmic ribosomes.
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36
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Mielenz JR, Milner JJ, Hershberger CL. Analysis of Euglena gracilis chloroplast deoxyribonucleic acid with a restriction endonuclease, EcoRI. J Bacteriol 1977; 130:860-8. [PMID: 233724 PMCID: PMC235292 DOI: 10.1128/jb.130.2.860-868.1977] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cleavage of chloroplast deoxyribonucleic acid (DNA) of Euglena gracilis Z with restriction endonuclease RI from Escherichia coli (EcoRI) yielded 23 bands upon electrophoresis in gels of agarose. Four of the bands contained twice the stoichiometric amount of DNA. One of these bands contained two similarly sized fragments. The sum of the molecular weight of the 24 different fragments equaled the molecular weight of the circular molecule. The restriction fragments had different buoyant densities, with four having distinctly heavy densities in CsCl. Restriction fragments with a high buoyant density were preferentially lost when broken chloroplast DNA was purified by equilibrium density gradient centrifugation. Hybridization of chloroplast ribosomal ribonucleic acid to intact chloroplast DNA determined that there are two cistrons for 16S and 23S ribosomal ribonucleic acid. These two cistrons are located on six restriction fragments, all of which have buoyant densities greater than the intact molecule of chloroplast DNA.
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37
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Gelvin S, Howell SH. Identification and Precipitation of the Polyribosomes in Chlamydomonas reinhardi Involved in the Synthesis of the Large Subunit of d-ribulose-1,5-bisphosphate Carboxylase. PLANT PHYSIOLOGY 1977; 59:471-7. [PMID: 16659875 PMCID: PMC542426 DOI: 10.1104/pp.59.3.471] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The size classes of polyribosomes involved in the synthesis of ribulose-1,5-bisphosphate carboxylase large subunit were determined by binding radioiodinated specific antibodies to polyribosomal preparations from Chlamydomonas reinhardi. Antibodies specific to the denatured large subunit and to the native enzyme bound primarily to small polyribosomes (N = two to five ribosomes). The binding of antibodies to small polyribosomes was unexpected since the large subunit is a large polypeptide (molecular weight 55,000) coded for by a corresponding large mRNA (12-14S). Control experiments showed that this unexpected pattern of antibody binding was not a result of messenger RNA degradation, "run-off" of ribosomes from polyribosomes, or adventitious binding of the completed enzyme to a selected class of polyribosomes. In addition, polyribosomes bearing nascent large subunit chains have been immunoprecipitated from small polyribosome fractions. A large RNA species that can direct the synthesis of large subunit in vitro was extracted from small polyribosomes.
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Affiliation(s)
- S Gelvin
- Department of Biology, University of California, San Diego, La Jolla, California 92093
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38
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Parker RD, MacInnis AJ. Hymenolepis diminuta: isolation, purification, and reconstruction in vitro of a cell-free system for protein synthesis. Exp Parasitol 1977; 41:2-16. [PMID: 320028 DOI: 10.1016/0014-4894(77)90125-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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39
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Barnett WE, Schwartzbach SD, Farrelly JG, Schiff JA, Hecker LI. Comments on the translational and transcriptional origin of Euglena chloroplastic aminoacyl-tRNA synthetases. Arch Microbiol 1976; 109:201-3. [PMID: 825072 DOI: 10.1007/bf00446628] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A response to: "A consideration of Euglena gracilis W3BUL as a cytoplasmic control for the wild-type phenylalanyl-tRNA synthetase system" and "A reinvestigation of the sites of transcription and translation of Euglena chloroplastic phenylalanyl-tRNA synthetase" by J. L. Lesiewicz and D. S. Herson.
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40
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Matson RS, Kimura T. Ferredoxin biosynthesis in Euglena gracilis. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 442:76-87. [PMID: 821536 DOI: 10.1016/0005-2787(76)90178-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Analysis of ferredoxin content in cultures of Euglena gracilis grown in the presence of selective antibiotic inhibitors of protein synthesis resulted in the following conclusions: 1. Ferredoxin is synthesized from cytoplasmic (80s-type) ribosomes; cycloheximide, a potent inhibitor of 80s translation completely abolished the synthesis, while the inhibitors of 70s translation chloramphenicol and erythromycin were not effective. In addition, ferredoxin was detected in a streptomycin-bleached mutant that lacks the chloroplast structure and chloroplast DNA. 2. Ferredoxin's transcript is presumably of nuclear origin; rifampicin, an inhibitor of chloroplast DNA-dependent RNA polymerase did not inhibit synthesis, while the streptomycin-bleached mutant continued to synthesize ferredoxin without chloroplast DNA.
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41
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Lewis FS, Rutman RJ, Avadhani NG. Messenger ribonucleic acid metabolism in mammalian mitochondria. Isolation and characterization of polyribosomes from Ehrlich ascites mitochondria. Biochemistry 1976; 15:3362-6. [PMID: 821518 DOI: 10.1021/bi00660a030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Mg2+ precipitation procedure of R. D. Palmiter ((1974) Biochemistry 13, 3606) has been used for preparative scale isolation of polysomes from Ehrlich ascites mitochondria. Digitonin-washed metochondria used for isolating the polysomes contain no detectable reduced nicotinamide adenine dinucleotide phosphate-cytochrome c reductase and over 200-fold reduced hexokinase activity. The mitochondrial polysomes exhibit a heterogeneous sedimentation and appear to contain highly aggregated particlses ranging over hexamers. These polysomes are sensitive to RNase, (ethylenedinitrilo)tetraacetic acid and puromycin. Mitochondrial polysomes are active in portein synthesis when supplied with supernatant enzymes from the homologous mitochondrial source or from Escherichia coli. Cytoplasmic enzymes, however, appear to be completely inactive. Protein synthesis by mitochrondrial polysomes is sensitive to chloramphenicol and resistant to cycloheximide and emetine. The procedure yields particles containing intact rRNAs. The extent of cytoplasmic RNA contaminating the total mitochondrial RNA or mitochondrial polysomal RNA has been estimated to be negligible.
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42
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Tiboni O, Di Pasquale G, Ciferri O. Ribosomes and translation factors from isolated spinach chloroplasts. ACTA ACUST UNITED AC 1976. [DOI: 10.1016/0304-4211(76)90124-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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43
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Heizmann PH, Salvador GF, Nigon V. Occurrence of plastidial rRNAs and plastidial structures in bleached mutants of Euglena gracilis. Exp Cell Res 1976; 99:253-60. [PMID: 817917 DOI: 10.1016/0014-4827(76)90581-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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44
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Alscher R, Smith MA, Petersen LW, Huffaker RC, Criddle RS. In vitro synthesis of the large subunit of ribulose diphosphate carboxylase on 70 S ribosomes. Arch Biochem Biophys 1976; 174:216-25. [PMID: 938052 DOI: 10.1016/0003-9861(76)90341-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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45
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Abstract
The 16S ribosomal RNA of the chloroplast of Euglena gracilis strain Z has been characterized in terms of its 2-dimensional electrophoretic "fingerprint" (T1 ribonuclease). Over 100 spots were resolved on the "fingerprint" and each spot was characterized as to which RNA oligonucleotide fragment(s) is contained. When compared to similar analyses of prokaryotic 16S rRNAs and eukaryotic cytoplasmic 18S rRNAs, the chloroplast 16S rRNA was a typically prokaryotic RNA, but bore little if any relationship to eukaryotic 18S rRNAs. Therefore, the cistrons for chloroplast 16S rRNA are related to the equivalent prokaryotic cistrons, but, apparently, are not related to the equivalent eukaryotic cistrons. Among the organisms available for comparison, the Euglena chloroplast 16S rRNA appears most closely related to the 16S rRNA of the eukaryote, Porphyridium cruentum (a red alga), and at least distantly related to the 16S rRNAs of the blue-green algae and perhaps also to the bacilli.
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46
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Schwartzbach SD, Schiff JA, Klein S. Biosynthetic events required for lag elimination in chlorophyll synthesis in Euglena. PLANTA 1976; 131:1-9. [PMID: 24424687 DOI: 10.1007/bf00387337] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/1975] [Accepted: 03/01/1976] [Indexed: 06/03/2023]
Abstract
Levulinic acid, a competitive inhibitor of δ aminolevulinic acid dehydratase, cycloheximide, an inhibitor of translation on 89s cytoplasmic ribosomes, and chloramphenicol, an inhibitor of translation on 68s chloroplast ribosomes, are reversible inhibitors of light induced chlorophyll synthesis in resting Euglena gracilis Klebs. When dark grown resting cells are preilluminated for 2 h followed by darkness for 12 h prior to exposure to continuous light, the usual lag period in chlorophyll formation is eliminated. If cycloheximide, chloramphenicol, or levulinic acid are present during either the preillumination period or the subsequent dark period, the lag is reestablished. Only the very beginning of the dark period is sensitive to cycloheximide but the dark period is less sensitive to levulinic acid than is the light period. Exposure of preilluminated cells to cycloheximide or levulinic acid at the time of exposure to continuous illumination completely inhibits chlorophyll synthesis indicating that the potential for rapid chlorophyll synthesis generated by preillumination and a dark period does not result simply from the accumulation of porphyrin precursors. Preillumination has little effect on the development of the capacity to fix CO2 photosynthetically. These results indicate that the control of chlorophyll formation is more complex than in higher plants and a model based on the formation of certain crucial enzymes in the porphyrin pathway, rather than simply upon the accumulation of δ aminolevulinic acid is presented to explain the experimental findings.
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47
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Saccone C, Quagliariello E. Biochemical studies of mitochondrial transcription and translation. INTERNATIONAL REVIEW OF CYTOLOGY 1976; 43:125-65. [PMID: 131112 DOI: 10.1016/s0074-7696(08)60068-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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48
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Mahler HR, Raff RA. The evolutionary origin of the mitochondrion: a nonsymbiotic model. INTERNATIONAL REVIEW OF CYTOLOGY 1976; 43:1-124. [PMID: 131111 DOI: 10.1016/s0074-7696(08)60067-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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49
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Lord JM, Armitage TL, Merrett MJ. Ribulose 1,5-Diphosphate Carboxylase Synthesis in Euglena: II. Effect of Inhibitors on Enzyme Synthesis during Regreening and Subsequent Transfer to Darkness. PLANT PHYSIOLOGY 1975; 56:600-4. [PMID: 16659352 PMCID: PMC541879 DOI: 10.1104/pp.56.5.600] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Dark-grown Euglena gracilis Klebs strain Z Pringsheim cells, which have been partially regreened in the light, show a striking, continued synthesis of the chloroplast enzyme ribulose 1,5-diphosphate carboxylase on transfer back into darkness. This dark synthesis of the enzyme was completely prevented by the addition of 15 mug/ml of cycloheximide to the culture medium but was unaffected, for at least 8 hours, by the addition of 1 mg/ml of d-threo-chloramphenicol. The addition of either cycloheximide or d-threo-chloramphenicol to dark-grown cultures at the onset of illumination completely inhibited the light-induced synthesis of ribulose 1,5-diphosphate carboxylase. When cells which had been illuminated in the presence of d-threo-chloramphenicol, and hence were unable to synthesize ribulose 1,5-diphosphate carboxylase, were transferred to darkness in the absence of this inhibitor, synthesis of the carboxylase then occurred. Dark-grown cells which had been illuminated in the presence of cycloheximide failed to synthesize the enzyme when placed in the dark in the absence of cycloheximide. The addition of 5-fluorouracil to regreening cultures to prevent light-induced transcriptional steps completely blocked the synthesis of ribulose 1,5-diphosphate carboxylase.
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Affiliation(s)
- J M Lord
- Postgraduate School of Studies in Biological Sciences, University of Bradford, Bradford, Yorkshire, BD7 1DP England
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50
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Margulies MM, Michaels A. Free and membrane-bound chloroplast polyribosomes Chlamydomonas reinhardtii. BIOCHIMICA ET BIOPHYSICA ACTA 1975; 402:297-308. [PMID: 1164519 DOI: 10.1016/0005-2787(75)90267-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Over half of the chloroplast ribosomes isolated from growing cultures of Chlamydomonas reinhardtii are bound to chloroplast thylakoid membranes if completion of nascent polypeptide chains is prevented by chloramphenicol. The free chloroplast ribosomes are recovered in homogenate supernatants, and presumably originate from the chloroplast stroma. Only about 10% of these free chloroplast ribosomes are polyribosomes, even under conditions when 70% of free cytoplasm ribosomes are recovered as polyribosomes. The nonionic detergent Nonidet P-40 liberates atypical polyribosomes (Type I), from membranes, which require both ribonuclease and proteases for complete conversion to monomeric ribosomes. Thus Type I particles are held together by mRNA but are also held together by peptide bonds. These Type I polyribosomes probably are not bound to intact membrane, but might be bound to some protein-containing sub-membrane particle. The Type I polyribosomes are dissociated to ribosomal subunits by puromycin and high salt, and contained 0.2 to 1 nascent chain per ribosome. If membranes are treated with Nonidet and proteases at the same time, polyribosomes which are digested to monomeric ribosomes by ribonuclease alone (Type II) are obtained. Type II polyribosomes are smaller than Type I, and probably represent the true size distribution of polyribosomes on the membranes. At least 50% of the membrane-bound ribosomes are polyribosomes, since that much membrane bound chloroplast RNA is recovered as Type I or Type II polyribosomes.
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