Photosynthetic Membrane System in
            <i>Anacystis nidulans</i>

Allen, Mary M.

doi:10.1128/jb.96.3.836-841.1968

Cited by 109 publications

(26 citation statements)

References 22 publications

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“…It should also be realized that the threedimensional ultrastructural characteristics of other cyanobacteria, especially the filamentous genera (1-3), probably differ from those of A. quadruplicatum. The other unicellular cyanobacteria may also differ from A. quadruplicatum, since they often appear to have distinct features in randomly cut thin sections (19,37,(40)(41)(42)(43)(44)(45)(46). Complete three-dimensional analyses of other unicellular cyanobacteria would be needed to determine how universally the features found in A. quadruplicatum occur in this group of organisms.…”

Section: Discussionmentioning

confidence: 99%

Three-dimensional ultrastructure of a unicellular cyanobacterium.

Nierzwicki‐Bauer¹,

Balkwill²,

Stevens³

1983

The Journal of Cell Biology

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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 structurefunction relationships in cyanobacteria.Cyanobacteria (blue-green algae) are phototrophic microorganisms that carry out a form of oxygenic photosynthesis similar to that of green plants. The internal organization of the cyanobacterial cell is prokaryotic, yet these organisms are considerably more structurally complicated than most other types of bacteria. The ultrastructure ofcyanobacteria has been studied extensively, and much is known about their basic subeellular features, the structural differences among the various genera and groups, and the effects of environmental factors on internal structures. (For reviews, see references 1-3.) Little is known, however, about how the ultrastructural features of cyanobacteria are arranged three-dimensionally within the cell. Most speculations concerning the three-dimensional architecture of these organisms have come about through extrapolation of the information in randomly cut, individual thin sections. There have been no reports describing three-dimensional reconstructions of entire cyanobacterial cells by serial sectioning or any other approach. Reconstructions of this type are needed, however, because they (a) would eliminate the need for extrapolation, (b) can resolve a number of uncertain issues in regard to cyanobacterial ultrastructure (see below), and (c) may lead to a better understanding of structure-function relationships in the cyanobacterial cell.Complete three-dimensional reconstructions of whole cells or cell organelles have been relatively rare because, until recently, the techniques for completing such reconstructions were cumbersome and time-consuming. However, the application of high-voltage electron microscopy (HVEM ~) to biological materials has now made it possible to view serial thick (0.25-1.0 tzm) sections without any significant loss in resolution (4-7). Since these sections are much thicker than conventional thin sections, fewer of them are required to cover a given sample volume during serial sectioning. Three-dimensional reconstructions have also been greatly facilitated by the development of computer programs designed to collect the informat...

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Section: Discussionmentioning

confidence: 99%

Three-dimensional ultrastructure of a unicellular cyanobacterium.

Nierzwicki‐Bauer¹,

Balkwill²,

Stevens³

1983

The Journal of Cell Biology

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“…As for all photosynthetic organisms, an inverse correlation exists between the amount of lightharvesting pigments and the photon flux density that reaches the cells. In Synechococcus PCC 6301, pigment concentration and thylakoid content vary inversely with photon fluency rate [31]. Upon transfer of cells from high to low light, the size of the antenna first increases (by elongation of the phycobilisome rods) followed by an increase in the number of phycobilisomes per unit area of thylakoid membrane, with the ratio of phycobilisomes/photosystem II reaction centres staying almost unchanged [32,33].…”

Section: Adaptation Of the Photosynthetic Apparatus To 'Light Intensity'mentioning

confidence: 99%

Adaptation of cyanobacteria to environmental stimuli: new steps towards molecular mechanisms

Marsac

Houmard

1993

FEMS Microbiology Letters

375

128

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Dating from the Pre‐Cambrian era, cyanobacteria have a long history of adaptation to the Earth's environment. By evolving oxygen via photosynthetic reactions similar to those of plants and green algae, these prokaryotes were essential to the evolution of the present biosphere. They continue to make a large contribution to the equilibrium of the Earth's atmosphere by production oxygen and removing carbon dioxide. To survive in extreme or variable environments, cyanobacteria have developed specific regulatory systems, in addition to more general mechanisms equivalent to those of other prokaryotes or photosynthesis eukaryotes. Specific regulatory systems control the differentiation of specialized nitrogen‐fixing cells and of cell types facilitating the dispersion of species. In the past decade, considerable progress has been made towards understanding the expression of the cyanobacterial genome in response to variations in the intensity and spectral quality of incident light and in response to nutritional conditions, especially carbon, nitrogen and sulphur sources. These studies have provided insights into the relationships between carbon and nitrogen intermediary metabolism, and a start towards understanding of the interconnected pathways which lead from the perception of environmental signals to the regulation of enzyme activities and gene expression. Cyanobacterial regulatory mechanisms share common features with those of other prokaryotes, but are unique since these essentially photo‐autotrophic organisms must maintain a proper cellular C/N balance, in spite of dailty variations in incident light. Thus an appropriate coordination between photosynthesis and other metabolic processes must be achieved through control of the catalytic activity of key enzymes by reducing equivalents and ATP produced by photosynthetic or respiratory electron transport. Recently discovered kinases/phosphatases act by post‐translational modification of specific proteins which probably act as signal transducers or modulators of gene expression in a manner similar to the well‐known two‐component regulatory systems described in other bacteria. In this overview, we present our current knowledge on the molecular aspects of the biology of cyanobacteria, as well as on their mechanisms of resistance to metal ions and their responses to metabolic stress.

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“…The influence of the growth factors CO 2 concentration and light intensity on the photosynthetic apparatus of cyanobacteria has been the subject of various studies (Allen, 1968;Eley, 1971;Yamanaka and Glazer, 1981;L6nneborg, 1985). The results seem to depend highly on the species studied and on the growth conditions used.…”

Section: Polypeptide Composition Ofthe Phycobilisomes Varied By Lightmentioning

confidence: 99%

Adaptation of the Photosynthetic Apparatus of Anacystis nidulans to Irradiance and CO₂‐Concentration

et al. 1993

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Introduction AbstractHomocontinuous cultures of the cyanobacterium Anacystis nidulans (syn. Synechococcus sp. PCC 6301) were grown at white light intensities of 2 and 20 W/rrr', and supplied with 0.03 and 3 % CO 2 enriched air. The mutual influence of these growth factors on the development of the photosynthetic apparatus was studied by analyses of the pigment content, by low temperature absorbance and fluorescence spectroscopy, by analyses of oxygen evolution light-saturation curves, and by SDS PAGE of isolated phycobilisomes.The two growth factors, light and COz, distinctly affect the absorption cross section of the photosynthetic apparatus. which is expressed by its pigment pattern. excitation energy distribution and capacity. In response to low COz concentrations, the phycocyanin I allophycocyanin ratios were lower and one linker polypeptide qo, of the phycobilisomes was no longer detectable in SDS PAGE. Apparently, low COz adaptation results in shorter phycobilisome rods. Specifically, upon adaptation to low light intensities, the chlorophyll and the phycocyanin content on a per cell basis increase by about 50 % suggesting a parallel increase in the amount of phycobilisomes and photosystem core-complexes. Low light adaptation and low CO 2 adaptation both cause a shift of the excitation energy distribution in favor of photosystem I. Variations in the content of the "anchor" polypeptides L~~and Ll~are possibly related to changes in the excitation energy transfer from phycobilisomes to the photosystem II and photosystem I core-complexes.

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Photosynthetic Membrane System in Anacystis nidulans

Cited by 109 publications

References 22 publications

Three-dimensional ultrastructure of a unicellular cyanobacterium.

Three-dimensional ultrastructure of a unicellular cyanobacterium.

Adaptation of cyanobacteria to environmental stimuli: new steps towards molecular mechanisms

Adaptation of the Photosynthetic Apparatus of Anacystis nidulans to Irradiance and CO₂‐Concentration

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Photosynthetic Membrane System in Anacystis nidulans

Cited by 109 publications

References 22 publications

Three-dimensional ultrastructure of a unicellular cyanobacterium.

Three-dimensional ultrastructure of a unicellular cyanobacterium.

Adaptation of cyanobacteria to environmental stimuli: new steps towards molecular mechanisms

Adaptation of the Photosynthetic Apparatus of Anacystis nidulans to Irradiance and CO2‐Concentration

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Adaptation of the Photosynthetic Apparatus of Anacystis nidulans to Irradiance and CO₂‐Concentration