Effect of chloramphenicol on membrane transformations in plastids

1971 ◽  
Vol 49 (4) ◽  
pp. 587-593 ◽  
Author(s):  
L. M. Srivastava ◽  
M. Vesk ◽  
A. P. Singh
Keyword(s):  
Electron Transfer ◽  
Fine Structure ◽  
Higher Plants ◽  
Protein S ◽  
Fraction I Protein ◽  
Prolamellar Bodies ◽  
Fraction I ◽  
Plastid Membranes ◽  
Plastid Ribosomes

At a concentration of 4 mg/ml chloramphenicol does not affect the formation and fine structure of prolamellar bodies. It also does not inhibit their light-induced loss and conversion into thyllakoids. It does, however, strongly affect the aggregation of thyllakoids into grana, most likely by retarding or interrupting some process(es) vital to the orderly assembly of thyllakoids. These results are discussed in light of the known effects of chloramphenicol on formation of pigments, electron-transfer and fraction I protein, and plastid membranes. It is suggested that the aggregation of thyllakoids into grana in higher plants may be regulated by some protein(s) synthesized by the plastid ribosomes, whereas the formation and maintenance of prolamellar bodies as well as the synthesis of plastid membranes may be regulated by protein(s) synthesized in the cytoplasm.

scholarly journals Protein synthesis in chloroplasts. Characteristics and products of protein synthesis in vitro in etioplasts and developing chloroplasts from pea leaves

1975 ◽  
Vol 146 (3) ◽  
pp. 675-685 ◽  
Author(s):  
S G Siddell ◽  
R J Ellis
Keyword(s):  
Energy Source ◽  
Protein Synthesis ◽  
Large Subunit ◽  
Sodium Dodecyl ◽  
Supernatant Fraction ◽  
Pisum Sativum L ◽  
Fraction I ◽  
Plastid Ribosomes

The function of plastid ribosomes in pea (Pisum sativum L.) was investigated by characterizing the products of protein synthesis in vitro in plastids isolated at different stages during the transition from etioplast to chloroplast. Etioplasts and plastids isolated after 24, 48 and 96h of greening in continuous white light, use added ATP to incorporate labelled amino acids into protein. Plastids isolated from greening leaves can also use light as the source of energy for protein synthesis. The labelled polypeptides synthesized in isolated plastids were analysed by electrophoresis in sodium dodecyl sulphate-ureapolyacrylamide gels. Six polypeptides are synthesized in etioplasts with ATP as energy source. Only one of these polypeptides is present in a 150 000g supernatant fraction. This polypeptide has been identified as the large subunit of Fraction I protein (3-phospho-D-glycerate carboxylyase EC 4.1.1.39) by comparing the tryptic ‘map’ of its L-(35S)methionine-labelled peptides with the tryptic ‘map’ of large subunit peptides from Fraction I labelled with L-(35S)methionine in vivo. The same gel pattern of six polypeptides is seen when plastids isolated from greening leaves are incubated with either added ATP or light as the energy source. However, the rates of synthesis of particular polypeptides are different in plastids isolated at different stages of the etioplast to chloroplast transition. The results support the idea that plastid ribosomes synthesize only a small number of proteins, and that the number and molecular weight of these proteins does not alter during the formation of chloroplasts from etioplasts.

scholarly journals Differential Localization of Fraction I Protein between Chloroplast Types

1976 ◽  
Vol 57 (5) ◽  
pp. 730-733 ◽  
Author(s):  
Steven C. Huber ◽  
Timothy C. Hall ◽  
Gerald E. Edwards
Keyword(s):  
Fraction I Protein ◽  
Differential Localization ◽  
Fraction I

scholarly journals Genetic fine-structure of the GA-1 locus in the higher plant Arabidopsis thaliana (L.) Heynh

1983 ◽  
Vol 41 (1) ◽  
pp. 57-68 ◽  
Author(s):  
M. Koornneef ◽  
J. Van Eden ◽  
C. J. Hanhart ◽  
A. M. M. De Jongh
Keyword(s):  
Arabidopsis Thaliana ◽  
Fine Structure ◽  
Higher Plants ◽  
Wild Type ◽  
Higher Plant ◽  
Selfed Progeny ◽  
Intragenic Deletion ◽  
Genetic Length ◽  
Genetic Fine Structure ◽  
Half Diallel

SUMMARYNon-germinating gibberellin (GA) responsive mutants are a powerful tool to study genetic fine structure in higher plants. Nine alleles (EMS-and fast neutron-induced) of the ga-1 locus of Arabidopsis thaliana were tested in a complete half-diallel. No wild type ‘recombinants’ were found in the selfed progeny of 9 homoallelic combinations (in total 3 × 105 plants); in the progenies from the 36 selfed hetero allelics the wild type frequency ranged from zero to 6·6 × 10−4. These frequencies allowed the construction of an internally consistent map for five different sites representing eight alleles. The ninth allele covered three sites and thus behaved like an intragenic deletion. The estimate of the total genetic length of the ga-1 locus was 0·07 cM. The order of the sites was also clearly reflected by the association with proximal outside markers. On the assumption that wild type gametes predominantly arise from reciprocal events, it was shown that a cross-over within the ga-1 locus leads to positive interference in the adjacent region.The results are discussed with respect to the mutagen used, the frequencies found in other plant and Drosophila genes, and the possible occurrence of gene conversion.

A specific immunoabsorbent for the isolation of fraction I protein

1976 ◽  
Vol 6 (2) ◽  
pp. 91-96 ◽  
Author(s):  
J.C. Gray ◽  
S.G. Wildman
Keyword(s):  
Fraction I Protein ◽  
Fraction I

Molecular Biology: Fraction I Protein

Nature ◽  
1972 ◽  
Vol 239 (5373) ◽  
pp. 432-432
Author(s):  
Keyword(s):  
Molecular Biology ◽  
Fraction I Protein ◽  
Fraction I

scholarly journals Metabolic regulation of photosynthetic membrane structure tunes electron transfer function

2018 ◽  
Vol 475 (7) ◽  
pp. 1225-1233 ◽  
Author(s):  
Matthew P. Johnson
Keyword(s):  
Electron Transfer ◽  
Metabolic Regulation ◽  
Higher Plants ◽  
Three Dimensional ◽  
Feedback Regulation ◽  
Membrane Dynamics ◽  
Dimensional Structure ◽  
Photosynthetic Membrane ◽  
Light Harvesting Complex ◽  
Light Harvesting Complex Ii

The photosynthetic chloroplast thylakoid membrane of higher plants is a complex three-dimensional structure that is morphologically dynamic on a timescale of just a few minutes. The membrane dynamics are driven by the phosphorylation of light-harvesting complex II (LHCII) by the STN7 kinase, which controls the size of the stacked grana region relative to the unstacked stromal lamellae region. Here, I hypothesise that the functional significance of these membrane dynamics is in controlling the partition of electrons between photosynthetic linear and cyclic electron transfer (LET and CET), which determines the ratio of NADPH/ATP produced. The STN7 kinase responds to the metabolic state of the chloroplast by sensing the stromal redox state. A high NADPH/ATP ratio leads to reduction of thioredoxin f (TRXf), which reduces a CxxxC motif in the stromal domain of STN7 leading to its inactivation, whereas a low NADPH/ATP ratio leads to oxidation of TRXf and STN7 activation. Phosphorylation of LHCII leads to smaller grana, which favour LET by speeding up diffusion of electron carriers plastoquinone (PQ) and plastocyanin (PC) between the domains. In contrast, dephosphorylation of LHCII leads to larger grana that slow the diffusion of PQ and PC, leaving the PQ pool in the stroma more oxidised, thus enhancing the efficiency of CET. The feedback regulation of electron transfer by the downstream metabolism is crucial to plant fitness, since perturbations in the NADPH/ATP ratio can rapidly lead to the inhibition of photosynthesis and photo-oxidative stress.

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