| | 1 | Author
| G. K. Ulandaivelu An, D.0 H All | Requires cookie* | | | Title
| Ultrastructural Changes in in vitro Ageing Spinach Chloroplasts  | | | | Abstract
| Ultrastructural changes in in vitro ageing spinach chloroplasts have been studied in detail. Prolonged storage caused swelling of the chloroplasts due to the increase in the thickness and spacing of the thylakoid membranes. The increase in the thickness of the membrane is partly ac companied by the release of lipids. Addition of crystalline bovine serum albumin was found to stabilize the membrane structures. Storage of the chloroplasts at 77 °K even though it resulted in complete breakage of the whole chloroplasts, maintained the thylakoid structures in a highly intact form. | | | |
Reference
| (Z. Naturforsch. 31c, 82 [1976]; received August 8 1975) | | | |
Published
| 1976 | | | |
Keywords
| Ultrastructure, Thylakoid Membrane, Ageing, Storage Conditions, Spinach | | | |
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| default:Reihe_C/31/ZNC-1976-31c-0082.pdf | | | | Identifier
| ZNC-1976-31c-0082 | | | | Volume
| 31 | |
| 2 | Author
| Wilhelm Menke, Alfons Radunz, GeorgH. Schmid, Friederike Koenig, Rolf-Dieter Hirtz | Requires cookie* | | | Title
| Intermolecular Interactions of Polypeptides and Lipids in the Thylakoid Membrane | | | | Abstract
| Intermolecular interactions between chloroplast lipids and a polypeptide fraction from thylakoids were investigated by far ultraviolet circular dichroism. The polypeptide fraction was isolated from dodecyl sulfate-containing buffers. It exhibits an average molecular weight of 24 000. The circular dichroism of this polypeptide fraction measured as mean residue ellipticity is greater in the presence of sodium dodecyl sulfate than in the absence of this detergent. This effect is reversible. Addition of sulfoquinovosyl diglyceride to the dodecyl sulfate-free solution of the polypeptide also causes an increase of the circular dichroism. This increase was only observed in the pH-range between 6.9 and 7.4. The effect of dodecyl sulfate or sulfolipid on the circular dichroism is inter preted to indicate an increase of a-helix content. Monogalactosyl diglyceride, digalactosyl di glyceride and phosphatidyl glycerol gave no reaction. The attempt to obtain a conformational analysis of the polypeptide in the different states did not yield an entirely satisfactory result. Anti sera to sulfolipid inhibit photosynthetic electron transport of stroma-freed chloroplasts in the region of light reaction I. This inhibition is restricted to the same pH-range as the non-covalent binding of sulfolipid to the polypeptides. It appears that in the cell membrane-bound metabolic processes are regulated by this pH-dependence of the sulfolipid-polypetide interactions. | | | |
Reference
| (Z. Naturforsch. 31c, 436 [1976]; received April 30 1976) | | | |
Published
| 1976 | | | |
Keywords
| Interactions, Polypeptides, Lipids, Thylakoid Membrane, Photosynthesis | | | |
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| default:Reihe_C/31/ZNC-1976-31c-0436.pdf | | | | Identifier
| ZNC-1976-31c-0436 | | | | Volume
| 31 | |
| 3 | Author
| Alfons Radunz | Requires cookie* | | | Title
| Localization of the Tri-and Digalactosyl Diglyceride in the Thylakoid Membrane with Serological Methods | | | | Abstract
| Trigalactosyl diglyceride was isolated from leaves of Urtica dioica and characterized by thin layer chromatography, infrared spectroscopy and by its fatty acid composition. An antiserum to the trigalactolipid was obtained by immunization of rabbits. By means of inhibition experiments with oligosaccharides and mono-and digalactosyl glycerol it was demonstrated that the antibodies are directed towards the a-galactosyl-(1 -> 6) -a-galactosyl-(1 — ► 6) -/5-galactosyl-(1 -*■ 1) -glycerol con figuration of the trigalactosyl diglyceride. Monogalactosyl diglyceride and sulfoquinovosyl diglyce ride do not react with this antiserum. However, a cross reaction was observed with digalactosyl diglyceride. The presence of antibodies to tri-and digalactosyl diglyceride was demonstrated in antisera to different chloroplast preparations of Antirrhinum majus and Spinacia oleracea. The antiserum to the trigalactolipid agglutinates stroma-freed chloroplasts. Membrane fragments obtained by the ultra sonication were precipitated. The antiserum is exhausted by trigalactosyl di glyceride but not by digalactosyl diglyceride or digalactosyl glycerol. The antiserum treated with digalactosyl glycerol and digalactosyl diglyceride also agglutinated stroma-freed chloroplasts. 1 g stroma-freed chloroplasts binds 0.17 g antibodies to trigalactolipid. Membrane fragments bind more antibodies to trigalactolipids than stroma-freed chloroplasts. From the agglutination tests it follows that the antigenic determinants of the trigalactolipid and the digalactolipid are localized in the outer surface as well as in the surface directed towards the inside of the thylakoid membrane. | | | |
Reference
| (Z. Naturforsch. 31c, 589 [1976]; received July 19 1976) | | | |
Published
| 1976 | | | |
Keywords
| Trigalactosyl Diglyceride, Digalactosyl Diglyceride, Antibodies, Chloroplasts, Thylakoid Membrane | | | |
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| default:Reihe_C/31/ZNC-1976-31c-0589.pdf | | | | Identifier
| ZNC-1976-31c-0589 | | | | Volume
| 31 | |
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