scholarly journals Supramolecular structure of the thylakoid membrane of Prochlorothrix hollandica: a chlorophyll b-containing prokaryote

1988 ◽  
Vol 91 (4) ◽  
pp. 577-586
Author(s):  
K.R. Miller ◽  
J.S. Jacob ◽  
T. Burger-Wiersma ◽  
H.C. Matthijs
Keyword(s):  
Thylakoid Membrane ◽  
Freeze Fracture ◽  
Thylakoid Membranes ◽  
Chlorophyll B ◽  
Photosynthetic Membranes ◽  
Green Plants ◽  
Membrane Surfaces ◽  
Chlorophylls A And B ◽  
Inner Surface ◽  
Etched Membrane

Prochlorothrix hollandica is a newly described photosynthetic prokaryote, which contains chlorophylls a and b. In this paper we report the results of freeze fracture and freeze etch studies of the organization of the photosynthetic thylakoid membranes of Prochlorothrix. These membranes exhibit four distinct fracture faces in freeze fractured preparations, two of which are derived from membrane splitting in stacked regions of the thylakoid membrane, and two of which are derived from nonstacked regions. The existence of these four faces confirms that the thylakoid membranes of Prochlorothrix, like those of green plants, display true membrane stacking and have different internal composition in stacked and non-stacked regions, a phenomenon that has been given the name lateral heterogeneity. The general details of these fracture faces are similar to those of green plants, although the intramembrane particles of Prochlorothrix are generally smaller than those of green plants by as much as 30%. Freeze etched membrane surfaces have also been studied, and the results of these studies confirm freeze fracture observations. The outer surface of the thylakoid membrane displays both small (less than 8.0 nm) and large (greater than 10.0 nm) particles. The inner surface of the thylakoid membrane is covered with tetrameric particles, which are concentrated into stacked membrane regions, a situation that is similar to the inner surfaces of the thylakoid membranes of green plants. These tetramers have never before been reported in a prokaryote. The photosynthetic membranes of Prochlorothrix therefore represent a prokaryotic system that is remarkably similar, in structural terms, to the photosynthetic membranes found in chloroplasts of green plants.

scholarly journals Biogenesis of thylakoid membranes is controlled by light intensity in the conditional chlorophyll b-deficient CD3 mutant of wheat.

1988 ◽  
Vol 107 (3) ◽  
pp. 907-919 ◽  
Author(s):  
K D Allen ◽  
M E Duysen ◽  
L A Staehelin
Keyword(s):  
Light Intensity ◽  
Chlorophyll A ◽  
Binding Proteins ◽  
Freeze Fracture ◽  
Thylakoid Membranes ◽  
High Light ◽  
General Context ◽  
Supramolecular Organization ◽  
Chlorophyll B ◽  
Wild Type

Biogenesis of thylakoid membranes in the conditional chlorophyll b-deficient CD3 mutant of wheat is dramatically altered by relatively small differences in the light intensity under which seedlings are grown. When the CD3 mutant is grown at 400 microE/m2 S (high light, about one-fifth full sunlight) plants are deficient in chlorophyll b (chlorophyll a/b ratio greater than 6.0) and lack or contain greatly reduced amounts of the chlorophyll a/b-binding complexes CPII/CPII (mobile or peripheral LHCII), CP29, CP24 and LHCI, as shown by mildly denaturing 'green gel' electrophoresis, by fully denaturing SDS-PAGE, and by Western blot analysis. High light CD3 chloroplasts display an unusual morphology characterized by large, sheet-like stromal thylakoids formed into parallel unstacked arrays and a limited number of small grana stacks displaced toward the edges of the arrays. Changes in the supramolecular organization of CD3 thylakoids, seen with freeze-fracture electron microscopy, include a reduction in the size of EFs particles, which correspond to photosystem II centers with variable amounts of attached LHCII, and a redistribution of EF particles from the stacked to the unstacked regions. When CD3 seedlings are grown at 150 microE/m2 S (low light) there is a substantial reversal of all of these effects. Thus, chlorophyll b and the chlorophyll a/b-binding proteins accumulate to near wild-type levels (chlorophyll a/b ratio = 3.5-4.5) and thylakoid morphology is more nearly wild type in appearance. Growth of the CD3 mutant in the presence of chloramphenicol stimulates the accumulation of chlorophyll b and its binding proteins (Duysen, M. E., T. P. Freeman, N. D. Williams, and L. L. Huckle. 1985. Plant Physiol. 78:531-536). We show that this partial rescue of the CD3 high light phenotype is accompanied by large changes in thylakoid structure. The CD3 mutant, which defines a new class of chlorophyll b-deficient phenotype, is discussed in the more general context of chlorophyll b deficiency.

Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

1967 ◽  
Vol 25 ◽  
pp. 74-75
Author(s):  
L. V. Leak
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Green Algae ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Cell Biol ◽  
Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

scholarly journals Three-dimensional ultrastructure of a unicellular cyanobacterium.

1983 ◽  
Vol 97 (3) ◽  
pp. 713-722 ◽  
Author(s):  
S A Nierzwicki-Bauer ◽  
D L Balkwill ◽  
S E Stevens
Keyword(s):  
Inclusion Bodies ◽  
Cytoplasmic Membrane ◽  
Three Dimensional ◽  
Thylakoid Membranes ◽  
Serial Sections ◽  
Unicellular Cyanobacterium ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Inner Surface ◽  
Computer Aided

The first complete three-dimensional ultrastructural reconstruction of a cyanobacterium was accomplished with high-voltage electron microscopy and computer-aided assembly of serial sections. The precise arrangement of subcellular features within the cell body was very consistent from one cell to another. Specialized inclusion bodies always occupied specific intracellular locations. The photosynthetic thylakoid membranes entirely surrounded the central portion of the cytoplasm, thereby compartmentalizing it from the rest of the cell. The thylakoid membranes formed an interconnecting network of concentric shells, merging only at the inner surface of the cytoplasmic membrane. The thylakoids were in contact with the cytoplasmic membrane at several locations, apparently to maintain the overall configuration of the thylakoid system. These results clarified several unresolved issues regarding structure-function relationships in cyanobacteria.

Isoelectric points of spinach thylakoid membrane surfaces as determined by cross partition

1979 ◽  
Vol 552 (2) ◽  
pp. 238-246 ◽  
Author(s):  
Hans-Erik Åkerlund ◽  
Bertil Andersson ◽  
Agneta Persson ◽  
Per-Åke Albertsson
Keyword(s):  
Thylakoid Membrane ◽  
Membrane Surfaces ◽  
Isoelectric Points ◽  
Spinach Thylakoid

Interactions between Photosynthetic Pigments Bound to Lipid and Protein Particles. Spectroscopic Properties

1979 ◽  
Vol 34 (7-8) ◽  
pp. 582-587
Author(s):  
Framçoise Techy ◽  
Monique Dinant ◽  
Jacques Aghion
Keyword(s):  
Chlorophyll A ◽  
Photosynthetic Pigments ◽  
Relative Concentration ◽  
Spectroscopic Properties ◽  
Chlorophyll B ◽  
Pheophytin A ◽  
Chlorophylls A And B ◽  
Protein Particles ◽  
Β Carotene

Abstract The spectroscopic (visible) properties of pigment-bearing lipid and protein particles extract­ ed from milk show that: 1) chlorophylls a and b bound to separate particles can form aggregates provided their relative concentration is high enough. Neither pheophytin a nor β-carotene, in the same conditions, form observable aggregates. 2) Chlorophylls a and b can co-aggregate when they are bound to the same particles. Pheophytin a as well as β-carotene seem to prevent the aggregation of chlorophyll a. β-carotene has no effect on the aggregation of chlorophyll b.

scholarly journals Reversible particle movements associated with unstacking and restacking of chloroplast membranes in vitro.

1976 ◽  
Vol 71 (1) ◽  
pp. 136-158 ◽  
Author(s):  
L A Staehelin
Keyword(s):  
Plasma Membranes ◽  
Structural Changes ◽  
Freeze Fracture ◽  
Chloroplast Membranes ◽  
Ps Ii ◽  
Membrane Particles ◽  
Intramembranous Particles ◽  
Membrane Surfaces ◽  
Ps Ii Activity

Freeze-fracture and freeze-etch techniques have been employed to study the supramolecular structure of isolated spinach chloroplast membranes and to monitor structural changes associated with in vitro unstacking and restacking of these membranes. High-resolution particle size histograms prepared from the four fracture faces of normal chloroplast membranes reveal the presence of four distinct categories of intramembranous particles that are nonrandomly distributed between grana and stroma membranes. The large surface particles show a one to one relationship with the EF-face particles. Since the distribution of these particles between grana and stroma membranes coincides with the distribution of photosystem II (PS II) activity, it is argued that they could be structural equivalents of PS II complexes. An interpretative model depicting the structural relationship between all categories of particles is presented. Experimental unstacking of chloroplast membranes in low-salt medium for at least 45 min leads to a reorganization of the lamellae and to a concomitant intermixing of the different categories of membrane particles by means of translational movements in the plane of the membrane. In vitro restacking of such experimentally unstacked chloroplast membranes can be achieved by adding 2-20 mM MgCl2 or 100-200 mM NaCl to the membrane suspension. Membranes allowed to restack for at least 1 h at room temperature demonstrate a resegregation of the EF-face particles into the newly formed stacked membrane regions to yield a pattern and a size distribution nearly indistinguishable from the normally stacked controls. Restacking occurs in two steps: a rapid adhesion of adjoining stromal membrane surfaces with little particle movement, and a slower diffusion of additional large intramembranous particles into the stacked regions where they become trapped. Chlorophyll a:chlorophyll b ratios of membrane fraction obtained from normal, unstacked, and restacked membranes show that the particle movements are paralleled by movements of pigment molecules. The directed and reversible movements of membrane particles in isolated chloroplasts are compared with those reported for particles of plasma membranes.

Lokalisierung des Monogalaktosyldiglycerids in Thylakoidmembranen mit serologischen Methoden / Serological Localisation of Monogalactosyl Diglyceride in Thylakoid Membranes

1972 ◽  
Vol 27 (7) ◽  
pp. 822-826 ◽  
Author(s):  
Alfons Radunz
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Thylakoid Membrane ◽  
Bovine Serum ◽  
Thylakoid Membranes ◽  
Specific Antiserum ◽  
Lamellar System ◽  
Chloroplast Membrane ◽  
Monogalactosyl Diglyceride

Immunoglobulins to monogalactosyl diglyceride have been found in antisera to different chloroplast preparations. A specific antiserum to this lipid has been obtained by injection of monogalactosyl diglyceride which was adsorbed onto methylated bovine serum albumin. Inhibition tests with mono- and oligosaccharides, as well as with mono- and digalactosyl glycerol, showed that the immunoglobulin was directed to the β-galactosyl-(1 → 1) -glycerol configuration. Digalactosyl diglyceride and sulphoquinovosyl diglyceride did not react with the antiserum. The immunoglobulin is of the Ig M-type.The antiserum to monogalactosyl diglyceride agglutinates stroma-freed chloroplasts. Fragments of the thylakoid membrane, obtained by ultrasonication and fractioning centrifugation, thylakoids and thylakoid stacks are all precipitated. In a preparation of stroma-containing chloroplasts agglutination takes place but after rupture of the chloroplast membrane and loss of the stroma. The ultrasonicated lamellar system binds a larger amount of the monogalactosyl diglyceride immunoglobulins than does stroma-freed chloroplasts. It is concluded from these experiments that some of the chloroplasts monogalactosyl diglyceride is located at the surface of the thylakoids.

Degradation of unassembled and damaged thylakoid proteins

2001 ◽  
Vol 29 (4) ◽  
pp. 427-430 ◽  
Author(s):  
Z. Adam ◽  
O. Ostersetzer
Keyword(s):  
Thylakoid Membrane ◽  
D1 Protein ◽  
Thylakoid Membranes ◽  
Reaction Centre ◽  
Ps Ii ◽  
Plant Genomes ◽  
Thylakoid Membrane Proteins ◽  
Luminal Side ◽  
Cytochrome Complex ◽  
Aaa Protein

To study protein degradation in thylakoid membranes we identified, characterized and cloned thylakoid proteases, and then linked them to known proteolytic processes. Several families of chloroplast proteases were identified and characterized to different extents. FtsH, an ATP-dependent metalloprotease that belongs to the AAA-protein family, was found to be integral to the thylakoid membrane, facing the stroma. It is involved in both the degradation of unassembled subunits of membrane complexes, such as the Rieske Fe-S protein of the cytochrome complex, and the degradation of oxidatively damaged proteins such as the D1 protein of the photosystem II (PS II) reaction centre. Plant genomes contain multiple isomers of this protease but the functional significance of this multiplication is not clear yet. A second protease, the serine ATP-independent DegP, was found to be strongly associated with the luminal side of the thylakoid membrane. Although a specific role has not yet assigned for it, its location suggests that it can degrade luminal soluble proteins as well as luminally exposed regions of thylakoid membrane proteins.

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