ACTION SPECTRA FOR PHOTOREACTIONS I AND II OF PHOTOSYNTHESIS IN THE BLUE‐GREEN ALGA <i>ANACYSTIS NIDULANS</i>

Wang, Richard T.; Stevens, C. L. R.; Myers, Jack

doi:10.1111/j.1751-1097.1977.tb07429.x

Cited by 89 publications

(33 citation statements)

References 21 publications

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“…We tentatively propose that each dimeric particle may contain one PSII reaction center, based on the following: in Chlamydomonas, each of the about 16-nm particles accounts for one reaction center (40). The thylakoids of Cyanidium, which are similar to those of Cyanophora in lacking the Chl a/b light-harvesting complex and employing phycobiliproteins instead, exhibit about 10-nm E-face particles which are believed to be analogous to the core of the 16-nm E-face particle (PSII) of Chlamydomonas (9,40) and thus might also contain one The observation that the majority of light energy absorbed by phycobiiproteins is transferred initially to PSII (17,33,37) (36). Lipopolysaccharide has also been detected biochemically (1).…”

Section: Discussionmentioning

confidence: 99%

“…In the thylakoids of these cyanelles and several other endosymbionts, cyanobacteria and red algal chloroplasts, both the intramembrane particles on the exoplasmic fracture face (E-face) and the phycobilisomes are aligned in long parallel rows (4,21,22,28). Inasmuch as the majority of light energy absorbed by phycobiliproteins is transferred initially to PSII (17,33,37), it has been proposed (but not directly demonstrated) that the aligned E-face particles are PSII complexes and are in direct contact with rows of phycobilisomes (31). Independent lines of evidence suggesting that these 10-nm E-face particles are PSII centers are that: (a) they are absent from the thylakoids of cyanobacterial heterocysts (12) which lack PSII; and (b) they are more numerous in PSII-enriched mutants of Cyanidium (39).…”

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confidence: 99%

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Structure of the Thylakoids and Envelope Membranes of the Cyanelles of Cyanophora paradoxa

Giddings¹,

Wasmann²,

Staehelin³

1983

Plant Physiol.

121

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The cyanelles of Cyanophora paradoxa Korsch. are photosynthetically active obligate endosymbionts in which phycobiliproteins serve as the major accessory pigments. Freeze-fracture electron micrographs of thylakoids in isolated cyanelies reveal long parallel rows of particles covering most of the E-face, while a more random particle arrangement is evident in some areas. The center-to-center spacing of particles within these rows is about 10 nanometers. Their mean diameter was measured at 9.4 nanometers. The particles on the P-face have a mean diameter of 7.2 nanometers. Thylakoids that retained nearly the full complement of phycobiliproteins (determined spectrophotometrically and by gel electrophoresis) were isolated from the cyanelies. In thin sections of these preparations, rows of disc-shaped phycobilisomes are evident on the surface of the thylakoids. The spacing of the rows of phycobilisomes corresponds to that of the rows of E-face particles (approximately 45 nanometers, center to center). The periodicity of the disc-shaped phycobilisomes within a row is 10 nanometers suggesting a one-to-one association between phycobilisomes and E-face particles.In addition, visualization of the protoplasmic surface (PS) of isolated thylakoids by freeze-etch electron microscopy shows that rows of discshaped phycobilisomes are aligned directly above rows of particles exhibiting two subunits, presumably the P-surface projections of the 10-nanometer intramembrane particles. These observations, together with earlier studies indicating that the 10-nanometer E-face particles probably represent photosystem II (PSII) complexes, suggest that phycobilisomes are positioned on the thylakoid surface in direct contact with PSII centers within the thylakoid membrane.The inner envelope membrane of the cyanelles, observed in freezefracture replicas, resembles cyanobacterial plasma membranes and is dissimilar to the chloroplast envelope membranes of red or green algae.The envelope of isolated cyanelies exhibits two additional layers: (a) a 5-to 7-nanometer-thick layer that lies adjacent to the inner membrane and which seems to correspond to the peptidoglycan layer of cyanobacteria; and (b) a layer external to the purported peptidoglycan layer that exhibits fracture faces similar to those of the lipopolysaccharide layer of gram negative bacteria. Our findings indicate that the supramolecular architecture of cyanelles differs only slightly from free-living cyanobacteria to which they are presumably related.Cyanobacteria, red algal chloroplasts and certain cyanobacteria- like endosymbionts, termed cyanelles, employ phycobiliproteins attached to the outer surface of their thylakoids as the major lightharvesting pigments for 02-evolving photosynthesis (3,7,10,29,35). In the atypical case of Gloeobacter violaceus, the phycobilisomes are attached to the plasma membrane (15). The cyanelles of Cyanophora paradoxa are generally regarded as cyanobacterial endosymbionts within a flagellated unicellular eukaryote (16,30,34). According to the end...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Structure of the Thylakoids and Envelope Membranes of the Cyanelles of Cyanophora paradoxa

Giddings¹,

Wasmann²,

Staehelin³

1983

Plant Physiol.

121

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“…In prokaryotic cyanobacteria and eukaryotic red algae, phycobilisomes are macromolecular complexes that harvest light energy and transfer this energy to the photosynthetic reaction centers (1). They can provide 30-50o of the lightharvesting capacity of the cells and can comprise 60% of the total soluble protein (2).…”

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confidence: 99%

Genes encoding major light-harvesting polypeptides are clustered on the genome of the cyanobacterium Fremyella diplosiphon.

Conley¹,

Lemaux²,

Lomax³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

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The polypeptide composition of the phycobilisome, the major light-harvesting complex of prokaryotic cyanobacteria and certain eukaryotic algae, can be modulated by different light qualities in cyanobacteria exhibiting chromatic adaptation. We have identified genomic fragments encoding a cluster of phycobilisome polypeptides (phycobiliproteins) from the chromatically adapting cyanobacterium Fremyella diplosiphon using previously characterized DNA fragments of phycobiliprotein genes from the eukaryotic alga Cyanophora paradoxa and from F. diplosiphon. Characterization of two A-EMBL3 clones containing overlapping genomic fragments indicates that three sets of phycobiliprotein genesthe a-and j3-allophycocyanin genes plus two sets of a-and j3-phycocyanin genes-are clustered within 13 kilobases on the cyanobacterial genome and transcribed off the same strand. The gene order (a-allophycocyanin followed by (3-allophycocyanin and ,B-phycocyanin followed by a-phycocyanin) appears to be a conserved arrangement found previously in a eukaryotic alga and another cyanobacterium. We have reported that one set of phycocyanin genes is transcribed as two abundant red light-induced mRNAs (1600 and 3800 bases). We now present data showing that the allophycocyanin genes and a second set of phycocyanin genes are transcribed into major mRNAs of 1400 and 1600 bases, respectively. These transcripts are present in RNA isolated from cultures grown in red and green light, although lower levels of the 1600-base phycocyanin transcript are present in cells grown in green light. Furthermore, a larger transcript of 1750 bases hybridizes to the allophycocyanin genes and may be a precursor to the 1400-base species.In prokaryotic cyanobacteria and eukaryotic red algae, phycobilisomes are macromolecular complexes that harvest light energy and transfer this energy to the photosynthetic reaction centers (1). They can provide 30-50o of the lightharvesting capacity of the cells and can comprise 60% of the total soluble protein (2). Although functionally analogous to light-harvesting chlorophyll-protein complexes in higher plants, the phycobilisome is water soluble and only peripherally associated with photosynthetic membranes. The complex is composed of chromophoric and nonchromophoric polypeptides arranged into two domains: a central core anchored to the photosynthetic membranes and rods that radiate from the core (3, 4). There are three major chromophoric proteins (phycobiliproteins) in the phycobilisomeallophycocyanin (APC), phycocyanin (PC), and phycoerythrin-as well as nonchromophoric linker polypeptides that maintain the structure and allow efficient energy transfer among the components of the complex (5). Each phycobiliprotein is composed of two related subunits, a and ,B, to which one or more tetrapyrole chromophores are attached (4), conferring upon each phycobiliprotein a characteristic light-absorption and emission spectrum. Amino acid (6-13) and DNA (14-16) sequence data show considerable sequence conservation among the various phyco...

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“…Phycobilisomes collect light energy and transfer it with nearly 100% efficiency to the photosynthetic reaction centers, primarily to those of PSII (4,16,17,27). Phycobilisomes can be isolated as intact, functional particles using mild detergents in high ionic strength buffers (1, 22).…”

mentioning

confidence: 99%

Light Intensity Adaptation and Phycobilisome Composition of Microcystis aeruginosa

Raps¹,

Kycia²,

Ledbetter³

et al. 1985

Plant Physiol.

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ACTION SPECTRA FOR PHOTOREACTIONS I AND II OF PHOTOSYNTHESIS IN THE BLUE‐GREEN ALGA ANACYSTIS NIDULANS

Cited by 89 publications

References 21 publications

Structure of the Thylakoids and Envelope Membranes of the Cyanelles of Cyanophora paradoxa

Structure of the Thylakoids and Envelope Membranes of the Cyanelles of Cyanophora paradoxa

Genes encoding major light-harvesting polypeptides are clustered on the genome of the cyanobacterium Fremyella diplosiphon.

Light Intensity Adaptation and Phycobilisome Composition of Microcystis aeruginosa

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