Ultrastructure of cell wall and thylakoid membranes of the thermophilic cyanobacterium Synechococcus lividus under the influence of temperature shifts

1979 ◽  
Vol 120 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Jochen R. Golecki
Keyword(s):  
Cell Wall ◽  
Thylakoid Membranes ◽  
Influence Of Temperature ◽  
Thermophilic Cyanobacterium ◽  
Synechococcus Lividus

Origin and Structure of Embryoids Arising From Epidermal Cells of the Stem of Ranunculus Sceleratus L

1972 ◽  
Vol 11 (1) ◽  
pp. 77-93 ◽  
Author(s):  
R. N. KONAR ◽  
E. THOMAS ◽  
H. E. STREET
Keyword(s):  
Cell Wall ◽  
Thylakoid Membranes ◽  
Callus Cultures ◽  
Central Nucleus ◽  
Zygotic Embryos ◽  
Embryological Development ◽  
Embryogenic Cells ◽  
Spherical Vesicles ◽  
Development Proceeds ◽  
Cytoplasmic Continuity

Embryoids are initiated from single highly cytoplasmic cells of the stem epidermis of plantlets of Ranunculus sceleratus L. derived from callus cultures. The embryoids show embryological development of the Crucifer type except that the suspensor is reduced or suppressed. The cells of the young embryoids have a large central nucleus surrounded by small vacuoles, a cytoplasm rich in free ribosomes or ribosomes in small polysomes, prominent amyloplastids and abundant spherosomes. These cells also frequently contain multivesicular and myelin bodies. The spherosomes are observed in various stages of development; they are typically arranged in a layer below the cell wall, the space between the spherosomes and the wall being rich in spherical vesicles and microtubules. As embryoid development proceeds the plastids show internal differentiation; globular centres and, surrounding them, electron-transparent droplets are associated with the origin of the thylakoid membranes. The walls of the embryogenic cells are initially rich in plasmodesmata but as the embryoid develops cytoplasmic continuity with the embedding tissue is severed and the embryoid is clearly delineated. The embryology and fine structure of the embryoid cells is compared with that of zygotic embryos of Capsella and Ranunculus.

scholarly journals Lipid and Fatty Acid Compositions of the Cytoplasmic and Thylakoid Membranes from the Thermophilic Cyanobacterium Synechococcus elongatus

1992 ◽  
Vol 41 (10) ◽  
pp. 1025-1028 ◽  
Author(s):  
Hisaaki YAGI ◽  
Sachio MIYAIRI ◽  
Toro NAKAHARA ◽  
Toshiaki ICHIMURA ◽  
Ikuo MATSUI ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Thylakoid Membranes ◽  
Synechococcus Elongatus ◽  
Thermophilic Cyanobacterium ◽  
Fatty Acid Compositions

scholarly journals Myxoxanthophyll Is Required for Normal Cell Wall Structure and Thylakoid Organization in the Cyanobacterium Synechocystis sp. Strain PCC 6803

2005 ◽  
Vol 187 (20) ◽  
pp. 6883-6892 ◽  
Author(s):  
Hatem E. Mohamed ◽  
Allison M. L. van de Meene ◽  
Robert W. Roberson ◽  
Wim F. J. Vermaas
Keyword(s):  
Cell Wall ◽  
Biological Significance ◽  
Thylakoid Membranes ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Reading Frame ◽  
Sugar Moiety ◽  
Severe Reduction ◽  
Altered Cell ◽  
Pcc 6803

ABSTRACT Myxoxanthophyll is a carotenoid glycoside in cyanobacteria that is of unknown biological significance. The sugar moiety of myxoxanthophyll in Synechocystis sp. strain PCC 6803 was identified as dimethyl fucose. The open reading frame sll1213 encoding a fucose synthetase orthologue was deleted to probe the role of fucose and to determine the biological significance of myxoxanthophyll in Synechocystis sp. strain PCC 6803. Upon deletion of sll1213, a pleiotropic phenotype was obtained: when propagated at 0.5 μmol photons m−2 s−1, photomixotrophic growth of cells lacking sll1213 was poor. When grown at 40 μmol photons m−2 s−1, growth was comparable to that of the wild type, but cells showed a severe reduction in or loss of the glycocalyx (S-layer). As a consequence, cells aggregated in liquid as well as on plates. At both light intensities, new carotenoid glycosides accumulated, but myxoxanthophyll was absent. New carotenoid glycosides may be a consequence of less-specific glycosylation reactions that gained prominence upon the disappearance of the native sugar moiety (fucose) of myxoxanthophyll. In the mutant, the N-storage compound cyanophycin accumulated, and the organization of thylakoid membranes was altered. Altered cell wall structure and thylakoid membrane organization and increased cyanophycin accumulation were also observed for Δslr0940K, a strain lacking ζ-carotene desaturase and thereby all carotenoids but retaining fucose. Therefore, lack of myxoxanthophyll and not simply of fucose results in most of the phenotypic effects described here. It is concluded that myxoxanthophyll contributes significantly to the vigor of cyanobacteria, as it stabilizes thylakoid membranes and is critical for S-layer formation.

scholarly journals Ycf48 involved in the biogenesis of the oxygen-evolving photosystem II complex is a seven-bladed beta-propeller protein

2018 ◽  
Vol 115 (33) ◽  
pp. E7824-E7833 ◽  
Author(s):  
Jianfeng Yu ◽  
Jana Knoppová ◽  
Franck Michoux ◽  
Wojciech Bialek ◽  
Ernesto Cota ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Photosynthetic Apparatus ◽  
Structural Features ◽  
Thylakoid Membranes ◽  
Cyanidioschyzon Merolae ◽  
Accessory Proteins ◽  
Thermophilic Cyanobacterium ◽  
Assembly Intermediate ◽  
Oxygen Evolving ◽  
D2 Protein

Robust photosynthesis in chloroplasts and cyanobacteria requires the participation of accessory proteins to facilitate the assembly and maintenance of the photosynthetic apparatus located within the thylakoid membranes. The highly conserved Ycf48 protein acts early in the biogenesis of the oxygen-evolving photosystem II (PSII) complex by binding to newly synthesized precursor D1 subunit and by promoting efficient association with the D2 protein to form a PSII reaction center (PSII RC) assembly intermediate. Ycf48 is also required for efficient replacement of damaged D1 during the repair of PSII. However, the structural features underpinning Ycf48 function remain unclear. Here we show that Ycf48 proteins encoded by the thermophilic cyanobacterium Thermosynechococcus elongatus and the red alga Cyanidioschyzon merolae form seven-bladed beta-propellers with the 19-aa insertion characteristic of eukaryotic Ycf48 located at the junction of blades 3 and 4. Knowledge of these structures has allowed us to identify a conserved “Arg patch” on the surface of Ycf48 that is important for binding of Ycf48 to PSII RCs but also to larger complexes, including trimeric photosystem I (PSI). Reduced accumulation of chlorophyll in the absence of Ycf48 and the association of Ycf48 with PSI provide evidence of a more wide-ranging role for Ycf48 in the biogenesis of the photosynthetic apparatus than previously thought. Copurification of Ycf48 with the cyanobacterial YidC protein insertase supports the involvement of Ycf48 during the cotranslational insertion of chlorophyll-binding apopolypeptides into the membrane.

scholarly journals The effect of kinetin on cytochemical localization of Mg++ dependent ATP-ase in isolated lupine cotyledons

2014 ◽  
Vol 50 (4) ◽  
pp. 575-581
Author(s):  
Roman Przymusiński ◽  
Adam Woźny ◽  
Fortunat Młodzianowski
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Thylakoid Membranes ◽  
Cytochemical Localization ◽  
Prolamellar Bodies

ATP-ase activity stimulated with Mg<sup>++</sup> ions was localized cytochermically in lupine cotyledons. Studies were also made of the effect of kinetin on this activity. Activity of Mg<sup>++</sup> dependent ATP-ase was observed in plasmalemma, nucleus, nucleolus, endoplasmic reticulum, thylakoid membranes, prolamellar bodies, cell wall, and irilter-cellular spaces. Kinetin (6-furfurylaminpurine) used in the experiment, stimulated ATP-ase activity, but dad not affect its localization.

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