The thylakoid membrane in a wide pH range

Summary The structural organisation of thylakoid systems of pea chloroplasts subjected to osmotic shock after incubation in a wide range of pH values (from 1.0 to 12.0) was studied. It was found that the percentage of thylakoid profiles stacked into granas is 86 % at pH 4.0, 72 % at pH 7.4 and 25 % at pH 10.0. In the pH range from 6.0 to 10.0 under the conditions of osmotic shock, a complete disordering of thylakoid systems, unstacking, and fragmentation of thylakoids are observed. Decreasing medium pH to 5.5-3.5 leads to a shortening of agranal thylakoids, the appearance of numerous lipid drops, and a shrinkage of thylakoid systems, which cease to respond to osmotic shock. Thylakoid systems remain structured, and the stacking in granas is retained. At pH levels from 3.0 to 1.0, thylakoid systems appear as spherical clusters of tightly stacked vesicles, whose structural organisation also does not change under osmotic shock. Increasing the pH of the medium to 11-12 leads to a complete unstacking of thylakoids and a swelling of single thylakoid sheets, which also do not respond to osmotic shock. A correlation between the release of acyl lipids from the thylakoid membrane and the loss of the native response of the membrane to osmotic shock is discussed.

[1]  G. Semenova Effect of urea and distilled water on the structure of the thylakoid system , 2001 .

[2]  G. Semenova The Relationship between the Transformation of Thylakoid Acyl Lipids and the Formation of Tubular Lipid Aggregates Visible on Fracture Faces , 1999 .

[3]  J. O’Sullivan,et al.  The Effect of a Thylakoid-Associated Galactolipase on the Morphology and Photochemical Activity of Isolated Wheat Leaf Chloroplasts , 1989 .

[4]  C. González-Murua,et al.  Effect of Phosphinothricin (Glufosinate) on Activities of Glutamine Synthetase and Glutamate Dehydrogenase in Medicago sativa L. , 1989 .

[5]  N. Warwick,et al.  A Galactolipase Activity Associated with the Thylakoids of Wheat Leaves (Triticum aestivum L.) , 1987 .

[6]  K. Miller,et al.  The effects of galactolipid depletion on the structure of a photosynthetic membrane , 1986, The Journal of cell biology.

[7]  P. Quinn,et al.  Low pH and phospholipase A2 treatment induce the phase‐separation of non‐bilayer lipids within pea chloroplast membranes , 1985 .

[8]  B. Ninham,et al.  An ion‐exchange model for thylakoid stacking in chloroplasts , 1981 .

[9]  P. Mohanty,et al.  THE EFFECT OF TREATMENT OF CHLOROPLAST MEMBRANES WITH GUANIDINE HC1 AND AQUEOUS ACETONE ON THE FLUORESCENCE OF BOUND ANS AND CHLOROPHYLL‐a † , 1981 .

[10]  B. Andersson,et al.  A mechanism for the formation of inside-out membrane vesicles. Preparation of inside-out vesicles from membrane-paired randomized chloroplast lamellae. , 1980, Biochimica et biophysica acta.

[11]  J. Barber,et al.  The relationship between thylakoid stacking and salt induced chlorophyll fluorescence changes. , 1980, Biochimica et biophysica acta.

[12]  J. Mullet,et al.  Simulation of grana stacking in a model membrane system. Mediation by a purified light-harvesting pigment-protein complex from chloroplasts. , 1980, Biochimica et biophysica acta.

[13]  L. Staehelin,et al.  Proteolysis of chloroplast thylakoid membranes. II. Evidence for the involvement of the light-harvesting chlorophyll a/b-protein complex in thylakoid stacking and for effects of magnesium ions on photosystem II-light-harvesting complex aggregates in the absence of membrane stacking. , 1980, Archives of biochemistry and biophysics.

[14]  F. Garlaschi,et al.  Influence of protons on thylakoid membrane stacking. , 1979 .

[15]  M. Anderson,et al.  Role of Galactolipids in Spinach Chloroplast Lamellar Membranes: II. Effects of Galactolipid Depletion on Phosphorylation and Electron Flow. , 1976, Plant physiology.

[16]  O. Hirayama,et al.  Effects of lipolytic enzymes on the photochemical activities of spinach chloroplasts. , 1976, Biochimica et biophysica acta.

[17]  L. Packer,et al.  The role of cations in the organization of chloroplast membranes. , 1971, Archives of biochemistry and biophysics.

[18]  L. Packer,et al.  PROTONATION AND CHLOROPLAST MEMBRANE STRUCTURE , 1970, The Journal of cell biology.

[19]  P. Siegenthaler Vieillissement de l'appareil photosynthétique I. Effet synergique de la lumière et du vieillissement in vitro sur les changements de volume de chloroplastes isolés d'épinard , 1969 .

[20]  P. J. Helmsing Hydrolysis of galactolipids by enzymes in spinach leaves. , 1967, Biochimica et biophysica acta.

[21]  M. Kates,et al.  HYDROLYSIS OF MONOGALACTOSYL AND DIGALACTOSYL DIGLYCERIDES BY SPECIFIC ENZYMES IN RUNNER-BEAN LEAVES. , 1964, Biochemistry.