The pyrenoid

Griffiths, D. J.

doi:10.1007/bf02859154

Cited by 92 publications

(52 citation statements)

References 63 publications

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“…Again one does not know if the enzyme is functional in each compartment. Another often suggested function of the pyrenoid of green algae is that they are involved in starch synthesis (9). Clearly immunocytochemical studies should be done to determine if the enzymes of starch synthesis are located in the pyrenoid.…”

Section: Discussionmentioning

confidence: 99%

Immunocytochemical Localization of Ribulose-1,5-Bisphosphate Carboxylase in the Pyrenoid and Thylakoid Region of the Chloroplast of Chlamydomonas reinhardtii

Lacoste-Royal¹,

Gibbs²

1987

Plant Physiol.

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The distribution of the large and small subunits of ribulose-1,5-bisphosphate carboxyhse in the chloroplast of Chiamydomomus reinhardtii was studied by immunoelectron microscopy by labeling Lowicrylembedded sections with antibody to each subunit followed by protein Agold. In light-harvested synchronously dividing cells, antibodies to each subunit heavily labeled the pyrenoid, whereas the thylakoid region of the plastid was lightly labeled. By estimating the volume of each chloroplast compartment, it was determined that approximately 40% of the total small subunit in the plastid and 30% of the large subunit are localized in the thylakoid region, presumably in the stroma. In synchronously dividing cells exposed to an extended dark period, the amount of labeling of the pyrenoid region by antibody to the small subunit stayed constant, but the labeling of the thylakoid region decreased. In stationary phase cells, the proportion of the label over the pyrenoid is higher than in synchronously dividing cells suggesting that the pyrenoid may be a storage organele.Pyrenoids are distinctive structures found in the chloroplasts of many species of algae from all algal classes and also in the plastid of the bryophyte Anthoceros. They are recognized as dense, homogeneous, occasionally crystalline, regions ofthe chloroplast stroma from which plastid ribosomes and DNA are excluded. Thylakoids are either absent in the pyrenoid region or reduced to varying degrees. The pyrenoids of green algae and Anthoceros are especially conspicuous for they are demarcated from the rest of the chloroplast by a shell of starch grains. In the groups of algae which store starch or a related polysaccharide outside the chloroplast, this photosynthate frequently caps the pyrenoid region of the chloroplast.Although it was realized early that pyrenoids were proteinaceous bodies, it was not until 1971 that Holdsworth (13)

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Section: Discussionmentioning

confidence: 99%

Immunocytochemical Localization of Ribulose-1,5-Bisphosphate Carboxylase in the Pyrenoid and Thylakoid Region of the Chloroplast of Chlamydomonas reinhardtii

Lacoste-Royal¹,

Gibbs²

1987

Plant Physiol.

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“…Pyrenoids can be used as a criterion for the classification of algae, and Myrmecia were found to have pyrenoids by Metting [52]. However, it should be noted that investigation of the presence of pyrenoids by light microscopy is not highly effective because of the lack of starches [53]. Using transmission electron microscopy, pyrenoids traversed by many parallel thylakoids membranes were observed in this study, and starch grains were clearly observed only when cells were grown under nitrogen stress conditions ( Figure 5), which is consistent with the results of a study conducted by Merzlyak et al [8].…”

Section: Taxonomy Position Of M Incisamentioning

confidence: 99%

Expressed sequence tags analysis revealing the taxonomic position and fatty acid biosynthesis in an oleaginous green microalga, Myrmecia incisa Reisigl (Trebouxiophyceae, Chlorophyta)

Ouyang

et al. 2012

Chin. Sci. Bull.

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cDNA library of Myrmecia incisa H4301 was constructed using λ phage vectors. The library consisted of 1.5×10 6 clones with a recombination rate of 90%, and 1942 clones were randomly sequenced. All 1854 readable expressed sequence tags (ESTs) were clustered into 596 non-redundant sequences (NRSs), among which 126 NRSs were from 1384 ESTs, showing a high redundancy. Among the 596 NRSs, 30 were ribosomal RNA, and 152 significantly matched with those available in NCBI database and JGI Genome Portal, the latter were divided into nine subcategories. Overall, 59 NRSs were involved in photosynthesis, the respiratory electron transport chain, ATP synthesis, oxidation reduction, fatty acid biosynthesis, glucose metabolism, protein metabolism, and small molecular metabolism, suggesting that these genes were abundantly transcribed during energy and substance metabolism. Acyl-carrier protein, ferrodoxin and fatty acid elongase genes obtained from this cDNA library enabled presumption of a possible biosynthesis pathway of ArA in M. incisa. Codon usage analysis of 142 NRSs with 17798 codons in the predicted coding regions showed that the average G+C content level of the total codons was 55.39%, and that of the third position in base trimers was 66.42%, indicating a strong bias toward cytosine and/or guanosine in this algal genome. Among all synonymous codons, NAG was most favored, while NUA was most avoided. Phylogenic trees inferred from ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit genes and the extra partial sequences of 18S rRNA obtained from this library demonstrated that M. incisa belonged to Trebouxiophyceae and was significantly clustered with M. incisa SAG 2007, Lobosphaera tirolensis, M. bisecta, and Parietochloris incisa, but was clearly distant from P. pseudoalveolaris and P. alveolar. Transmission electron microscopy revealed pyrenoids traversed by many parallel thylakoids membranes, while starch grains were only clearly observed when cells were grown under nitrogen stress. Based on combined investigation of the phylogeny and morphological characteristics, it is proposed that M. incisa be kept in the genus Myrmecia in which there might be two parallel groups, one living freely and another symbiotic species.

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“…Porphyra spp. ), excavates (Euglenophyceae), rhizarians (Chlorarachniophyceae), cryptophytes, some dinophytes and ochrophytes (Gibbs, 1962;Drum & Pankratz, 1964;Bouck, 1965;Dodge, 1968;Griffiths, 1970;Marchant, 1972;Dodge, 1973;Gayral & Billard, 1977;Vaughn et al, 1990;van den Hoek et al, 1995). Their composition and biological roles are not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Systematics and evolutionary history of pyrenoid-bearing taxa in brown algae (Phaeophyceae)

Silberfeld

Racault

Fletcher

et al. 2011

European Journal of Phycology

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In brown algae (Phaeophyceae), only a few taxa are reported to have plastids containing pyrenoids and this character has often been used for systematic delineation. Members of the Ectocarpales display large, stalked and exserted pyrenoids in their plastids, whereas the Scytothamnales, as well as the genera Asterocladon, Asteronema and Bachelotia, exhibit plastids arranged in a stellate configuration with pyrenoids embedded in the plastid stroma. The evolution of plastid characters has remained difficult to establish, especially because of a persistent lack of resolution in brown algal molecular phylogenies. Here, we generated a seven-locus dataset for a species-rich taxon sampling, to reassess phylogenetic relationships of pyrenoid-bearing brown algal taxa. Within the Ectocarpales, the relationships among families are clarified. The minute chordariacean genus Herponema is assigned to the family Acinetosporaceae. The systematic positions of two enigmatic genera are revised: Chordariopsis is assigned to the Adenocystaceae, and Spongonema is transferred back to the Ectocarpaceae. The new order Asterocladales, which is sister to the Ectocarpales, is proposed to accommodate species of the genus Asterocladon. The order Scytothamnales is shown to include the genus Bachelotia in a new family Bachelotiaceae, as well as another new family Asteronemataceae, accommodating the genus Asteronema. These new taxonomic insights also shed light on the evolution of plastid morphology and arrangement in brown algae. Stellate plastid configurations have evolved independently in Asterocladales and Scytothamnales. Evolutionary scenarios underlying the diversity of stellate configurations in the Scytothamnales and the Asterocladales-Ectocarpales lineage are discussed.

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The pyrenoid

Cited by 92 publications

References 63 publications

Immunocytochemical Localization of Ribulose-1,5-Bisphosphate Carboxylase in the Pyrenoid and Thylakoid Region of the Chloroplast of Chlamydomonas reinhardtii

Immunocytochemical Localization of Ribulose-1,5-Bisphosphate Carboxylase in the Pyrenoid and Thylakoid Region of the Chloroplast of Chlamydomonas reinhardtii

Expressed sequence tags analysis revealing the taxonomic position and fatty acid biosynthesis in an oleaginous green microalga, Myrmecia incisa Reisigl (Trebouxiophyceae, Chlorophyta)

Systematics and evolutionary history of pyrenoid-bearing taxa in brown algae (Phaeophyceae)

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