Behavior of mitochondria in synchronized cells of Chlamydomonas reinhardtii

Ehara, Tomoko

doi:10.5685/plmorphol.10.50

Cited by 20 publications

(25 citation statements)

References 16 publications

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“…The upper part, or ATP-investment phase, of glycolysis may occur in the cytosol or, alternatively, triosephosphates could be directly delivered from the chloroplasts to mitochondria (figure 1b), thus establishing a direct link between the Calvin cycle and mitochondrial metabolism (Liaud et al 2000). Importantly, optimized transfer of metabolites between chloroplasts and mitochondria is not without precedent: C. reinhardtii mitochondria penetrate into the chloroplast (Ehara et al 1995), and in malarial parasites the mitochondrion and apicoplast are closely associated and the enzymes required for haem biosynthesis partition across both compartments and the cytosol (Ralph et al 2004;Varadharajan et al 2004;van Dooren et al 2006).…”

Section: Compartmentalizing Glycolysismentioning

confidence: 99%

Rewiring and regulation of cross-compartmentalized metabolism in protists

Ginger

McFadden

Michels

2010

Phil. Trans. R. Soc. B

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Plastid acquisition, endosymbiotic associations, lateral gene transfer, organelle degeneracy or even organelle loss influence metabolic capabilities in many different protists. Thus, metabolic diversity is sculpted through the gain of new metabolic functions and moderation or loss of pathways that are often essential in the majority of eukaryotes. What is perhaps less apparent to the casual observer is that the sub-compartmentalization of ubiquitous pathways has been repeatedly remodelled during eukaryotic evolution, and the textbook pictures of intermediary metabolism established for animals, yeast and plants are not conserved in many protists. Moreover, metabolic remodelling can strongly influence the regulatory mechanisms that control carbon flux through the major metabolic pathways. Here, we provide an overview of how core metabolism has been reorganized in various unicellular eukaryotes, focusing in particular on one near universal catabolic pathway (glycolysis) and one ancient anabolic pathway (isoprenoid biosynthesis). For the example of isoprenoid biosynthesis, the compartmentalization of this process in protists often appears to have been influenced by plastid acquisition and loss, whereas for glycolysis several unexpected modes of compartmentalization have emerged. Significantly, the example of trypanosomatid glycolysis illustrates nicely how mathematical modelling and systems biology can be used to uncover or understand novel modes of pathway regulation.

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Section: Compartmentalizing Glycolysismentioning

confidence: 99%

Rewiring and regulation of cross-compartmentalized metabolism in protists

Ginger

McFadden

Michels

2010

Phil. Trans. R. Soc. B

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“…Even in unicellular eukaryotes such as yeasts and C. reinhardtii, mitochondrial shape changes dynamically from small spherical structures to a fused giant network during the cell cycle (Ehara et al, 1995). It is therefore difficult to sample a mitochondrial division event, thus C. merolae seems to be a model system for observing mitochondrial division.…”

Section: Mitochondriamentioning

confidence: 99%

Cyanidioschyzon merolae Genome. A Tool for Facilitating Comparable Studies on Organelle Biogenesis in Photosynthetic Eukaryotes

Misumi¹,

Matsuzaki²,

Nozaki³

et al. 2005

Plant Physiology

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The ultrasmall unicellular red alga Cyanidioschyzon merolae lives in the extreme environment of acidic hot springs and is thought to retain primitive features of cellular and genome organization. We determined the 16.5-Mb nuclear genome sequence of C. merolae 10D as the first complete algal genome. BLASTs and annotation results showed that C. merolae has a mixed gene repertoire of plants and animals, also implying a relationship with prokaryotes, although its photosynthetic components were comparable to other phototrophs. The unicellular green alga Chlamydomonas reinhardtii has been used as a model system for molecular biology research on, for example, photosynthesis, motility, and sexual reproduction. Though both algae are unicellular, the genome size, number of organelles, and surface structures are remarkably different. Here, we report the characteristics of double membrane-and single membrane-bound organelles and their related genes in C. merolae and conduct comparative analyses of predicted protein sequences encoded by the genomes of C. merolae and C. reinhardtii. We examine the predicted proteins of both algae by reciprocal BLASTP analysis, KOG assignment, and gene annotation. The results suggest that most core biological functions are carried out by orthologous proteins that occur in comparable numbers. Although the fundamental gene organizations resembled each other, the genes for organization of chromatin, cytoskeletal components, and flagellar movement remarkably increased in C. reinhardtii. Molecular phylogenetic analyses suggested that the tubulin is close to plant tubulin rather than that of animals and fungi. These results reflect the increase in genome size, the acquisition of complicated cellular structures, and kinematic devices in C. reinhardtii.To date, the genomes of more than 200 prokaryotes and several eukaryotes, including an alga, fungi, plants, animals, and their parasites, are known. However, we have little insight into the genomes of photosynthetic eukaryotes, such as Chlamydomonas reinhardtii, which are evolutionary intermediate organisms between primitive alga (Cyanidioschyzon merolae) and higher plants (Arabidopsis [Arabidopsis thaliana] and Oryza sativa), although such information would prove invaluable for investigations of the fundamental traits, origin, and evolution of eukaryotic and plant cells.The primitive red alga C. merolae is a small (1.5 mm in diameter) organism that lives in sulfate-rich hot springs (pH 1.5, 45°C;De Luca et al., 1978). It has many characteristics that make it an ideal organism for elucidating the function, biosynthesis, and multiplication of organelles in eukaryotic cells. Figure 1 summarizes the dynamic changes in fine structures during mitosis in C. merolae compared with typical eukaryotic cells. A detailed description of the behavior and genes of each organelle will be shown in ''Results and Discussion.'' Although a typical eukaryotic cell contains one nucleus, it has many double membranebound (nucleus, mitochondria, and plastids) and single membrane...

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“…Within C. reinhardtii cells, mitochondria have been observed to vary greatly in size, number, and shape, either throughout the cell cycle (Blank et al, 1980) or during specific phases of the cell cycle (Osafune et al, 1972(Osafune et al, , 1975Ehara et al, 1995). Mitochondrial changes in response to changes in CO, have not been reported in Chlamydomonas, although there have been reports of mitochondrial relocation in other algal species (Kramer and Findenegg, 1978;Tsuzuki et al, 1986).…”

mentioning

confidence: 99%

Molecular and Structural Changes in Chlamydomonas under Limiting CO2 (A Possible Mitochondrial Role in Adaptation)

Geraghty

Spalding

1996

Plant Physiology

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When Chlamydomonas reinhardtii cells are transferred to limiting CO,, one response is the induction of a C0,-concentrating mechanism (CCM) with components that remain t o be identified.Characterization of membrane-associated proteins induced by this transfer revealed that synthesis of the 21-kD protein (LIP-21) was regulated at the level of translatable message abundance and correlated well with the induction of CCM activity. Phase partitioning of LIP-21 and the previously characterized LIP-36 showed that both appeared to be peripherally associated with membranes, which limits their potential to function as transporters of inorganic carbon. Ultrastructural changes that occur when cells are transferred t o limiting CO, were also examined t o help form a model for the CCM or other aspects of adaptation to limiting CO,. Changes were observed in vacuolization, starch distribution, and mitochondrial location. The mitochondria relocated from within the cup of the chloroplast t o between the chloroplast envelope and the plasma membrane. In addition, immunogold labeling demonstrated that LIP-21 was localized specifically t o the peripheral mitochondria. These data suggest that mitochondria, although not previously incorporated into models for the CCM, may play an important role i n the cell's adaptation t o limiting CO,.

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Behavior of mitochondria in synchronized cells of Chlamydomonas reinhardtii

Cited by 20 publications

References 16 publications

Rewiring and regulation of cross-compartmentalized metabolism in protists

Rewiring and regulation of cross-compartmentalized metabolism in protists

Cyanidioschyzon merolae Genome. A Tool for Facilitating Comparable Studies on Organelle Biogenesis in Photosynthetic Eukaryotes

Molecular and Structural Changes in Chlamydomonas under Limiting CO2 (A Possible Mitochondrial Role in Adaptation)

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