Eignung intakter Caryophyllaceen-Samen für die Bestimmung der DNA-, RNA- und Proteinsynthese durch Einbauversuche

Bernhardt, D.; Hecker, Michael; Bernhardt, H

doi:10.1016/s0015-3796(17)30392-x

Cited by 15 publications

(4 citation statements)

References 24 publications

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“…Embryos were excised from seeds which were taken from several pods. For pulse-labeling, samples of five embryos were incubated in 150 Al 10 mm KCI, 1 mM CaC12, and 50 Ag ml-' chloramphenicol (2) to which the labeled precursors were added. After the pulse, the embryos were rinsed in distilled H20 and transferred to filter paper moistened with the KCI-CaCl2-chloramphenicol solution containing 100 mm of the appropriate unlabeled precursor and after a 2-h chase to fresh solution containing 10 deed, after a 5.5-h chase, all four bands had disappeared almost totally.…”

Section: Methodsmentioning

confidence: 99%

Biosynthesis of Storage Proteins in Ripening Agrostemma githago L. Seeds

Klerk

1984

Plant Physiol.

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The synthesis of storage proteins in ripening Agrostemma githago seeds was studied by in vivo pulse and pulse-chase experiments with labeled amino acids and labeled glucosamine. It was found that storage proteins were not synthesized directly, but via cleavage of several lrge precursor proteins. Two disulfide-linked proteins of38 and 25 kilodaltons were synthesized via a single large precursor protein. This precwusor protein contained internal disulfide bridges, at least one of which is involved in holding the subunit structre together following cleavage of the precursor. A similar mode of biosynthesis was noted for two other disulfide-linked proteins of 36 and 22 kilodaltons. The half-life of the precursors was about 2 hours. This mode of processing is a to the synthesis of legumin in legumes and globulin in oats. A third pair of disulfide-bonded proteins (41 and 23 kilodaltons) was synthesized from a precursor protein in several steps. These included a legumin-lke cleavage, whereafter the subunits remained disu}fide-bonded. Then, from the largest subunit, a part was cleaved off, probably a storage protein of 17 kilodaltons. This 17-kilUlton protein was not disulie-bonded to the 41 and 23-kihlodton complex. The first processing step was fast, the second slow: The half-lives of the precursors were about 3 and 10 hours, respectvely. Finally, a group of 16-and 17-kilodalton proteins was synthesized by cleavage of arge precursor proteins, likely in two steps. After cleavage, the proteins were not disulfide-bonded. The half-lfe of the precursors was short, less than 1 hour. In addition, for the 38-, 23-, and one of the 17-kilodalton proteins, a small decrease of relative molecular weight was observed as a last processing step. This was likely due to deglycosylation.Numerous studies have been carried out on the synthesis of storage proteins in ripening seeds (for reviews, see 6, 23). It has been found that in many species storage proteins are not synthesized directly but by cleavage of high mol wt precursor proteins. The precursor proteins may undergo several co-and post-translational modifications before yielding the final storage proteins. First, comparison of in vivo and in vitro translation products showed that the latter are normally a few kD larger. Probably, in vivo, a signal peptide is removed co-translationally (7,19). Second, some storage proteins are glycosylated. It was shown for phaseolin in beans (3) and conglycinin in soybeans (24) that cotranslational glycosylation is followed by a second glycosylation step. Third, following synthesis, the precursor may undergo cleavage. It was found for legumin in peas (1 1, 25), glycinin in soybeans (1, 24, 27), and globulin in oats (5) that the precursor protein is split into two subunits which, after cleavage, remain connected by a disulfide bridge. It might be that, such as in the processing of pro-insulin in animals, a connecting peptide is excised (26). In peas the lower mol wt vicilin subunits are also derived from large precursor proteins. After the s...

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Section: Methodsmentioning

confidence: 99%

Biosynthesis of Storage Proteins in Ripening Agrostemma githago L. Seeds

Klerk

1984

Plant Physiol.

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“…act. 37TBq/mmol) and 5 ul (25 ug) securopen (azlocillin) to prevent growth of bacteria (Bernhardt et al, 1978). If the seeds were incubated with cyanide or azide the concentration of the radioactive material was doubled and trebled, respectively, because methionine uptake and incorporation was markedly reduced by these substances.…”

Section: Methodsmentioning

confidence: 99%

Changes in the synthesis of some proteins during breaking of secondarily induced thermodormancy by respiration inhibitors (cyanide, azide) and BAP in embryos ofAgrostemma githagoL. seeds

Bernhardt

Gerth

1994

Seed Sci. Res.

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Secondary dormancy (thermodormancy) in Agrostemma githago L. seeds, caused by imbibing the seeds for 4 d at 35°C in the dark, is broken under the influence of cyanide (10 mM), azide (1 mM or BAP (0.44 mM). Both respiration inhibitors (cyanide and azide) and BAP increase the synthesis of five specific soluble proteins in the embryo axes and cotyledons. The activity of β-cyanoalanine synthase (β-CAS, EC 4.4.1.9.), which is able to detoxify cyanide, decreased in response to cyanide and azide. The relevance of these findings to the breaking of thermodormancy is discussed.

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“…Samples of 10 embryos were isolated from seeds after different periods of imbibition under dim, green safe-light (Schott filter VG 9, Schott and Gen., Jena). To determine DNA, RNA and protein synthesis 10 embryos were labelled at various times after the start of imbibition with either 380 kBq methyl 3 H-thymidine (1147 GBq mmoH), 380 kBq 5-3 H-uridine (740 GBq mmol" 1 ) or 38 kBq U-14 C-leucine (8880 MBq mmol" 1 ) in Esmarch-dishes (diameter 4.0 cm) in a volume of 1 ml for 2 h at 20°C in the dark, with the addition of 50 ug ml" 1 Securopen (azlocillin, Bayer, Leverkusen) to prevent bacterial growth (Bernhardt et al, 1978). Extraction of DNA and proteins was performed with ice-cold 50 rr\M Tris-HCl-buffer (pH 7.5) containing 0.5% SDS and 2 mil MgSO 4 .…”

Section: Measurement Of Dna Rna and Protein Synthesismentioning

confidence: 99%

A comparison of the synthesis of DNA, RNA and proteins in the embryos of after-ripened and thermo- or FR-dormantAgrostemma githagoL. seeds

Gerth

Bernhardt

1995

Seed Sci. Res.

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Imbibed embryos of after-ripened and secondarily thermo- and FR-dormant Agrostemma githago seeds were investigated as to their ability to synthesize DNA, RNA and proteins with the aim of finding characteristic differences connected with the induction and maintenance of developmental arrest. A gradual decrease in DNA synthesis was observed during the induction of thermodormancy. However, DNA synthesis was stimulated up to that of embryos of 30–h-imbibed after-ripened seeds within 24 h approximately after transferring the thermodormant seeds into temperatures which normally allow germination. DNA synthesis of embryos of FR-dormant seeds remained constant at a relatively low level during 7 d FR and another 7 d dark incubation. RNA synthesis decreased to different extents during induction of thermo- and FR-dormancy when it was arrested at a relatively low level in seeds transferred to temperatures which normally allow germination. Processes leading to an increase in RNA synthesis such as in embryos of after-ripened seeds appeared to be quantitatively and/or qualitatively repressed. Interestingly, protein synthesis was extremely depressed during induction of thermodormancy whereas it was slightly stimulated during induction of FR-dormancy. Nevertheless two-dimensional protein PAGE revealed several polypeptides which were new, increased, decreased or not synthesized predominantly in axes of thermo- and FR-dormant seeds in comparison to germinating after-ripened seeds. It is suggested that a connection exists between these polypeptides and the repression of germination. After transferring seconarily dormant seeds to temperatures which normally allow germination, a temporary stimulation of protein synthesis could be observed in both cases.

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Eignung intakter Caryophyllaceen-Samen für die Bestimmung der DNA-, RNA- und Proteinsynthese durch Einbauversuche

Cited by 15 publications

References 24 publications

Biosynthesis of Storage Proteins in Ripening Agrostemma githago L. Seeds

Biosynthesis of Storage Proteins in Ripening Agrostemma githago L. Seeds

Changes in the synthesis of some proteins during breaking of secondarily induced thermodormancy by respiration inhibitors (cyanide, azide) and BAP in embryos ofAgrostemma githagoL. seeds

A comparison of the synthesis of DNA, RNA and proteins in the embryos of after-ripened and thermo- or FR-dormantAgrostemma githagoL. seeds

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