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Tsuneyoshi Kuroiwa - One of the best experts on this subject based on the ideXlab platform.
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phototaxis in the unicellular red algae cyanidioschyzon merolae and Cyanidium caldarium
Cytologia, 2011Co-Authors: Mio Ohnuma, Osami Misumi, Tsuneyoshi KuroiwaAbstract:Phototaxis of 2 cyanidiaceae, Cyanidioschyzon merolae and Cyanidium caldarium, was studied by population experiments. We found that cells of both C. merolae and C. caldarium moved towards light in liquid medium, but that the degree of migration was quite different. When laterally illuminated, most of the C. merolae cells moved towards light at a velocity of 0.27 mm/h. In contrast, only a small proportion of C. caldarium cells showed migration towards light and most of the cells remained dispersed. The exterior cell surface of C. merolae was observed by scanning electron microscopy. It appeared thick and flexible enough to enable crawling movement.
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Isolation, characterization, and chromosomal mapping of an ftsZ gene from the unicellular primitive red alga Cyanidium caldarium RK-1.
Current genetics, 2000Co-Authors: Manabu Takahara, Shigeyuki Kawano, Hidenori Takahashi, Sachihiro Matsunaga, Atsushi Sakai, Tsuneyoshi KuroiwaAbstract:The FtsZ protein is involved in eukaryote plastid division, but there is little information on its involvement in the plastid-dividing apparatus. To investigate the relationship between FtsZ and the plastid-dividing ring, the ftsZ gene was isolated from the unicellular primitive red alga Cyanidium caldarium RK-1. Comparison of several prokaryotic and eukaryotic FtsZ proteins shows that there are six highly conserved domains in the core region of FtsZ. To determine the chromosomal location of ftsZ, we first determined the electrophoretic karyotype of C. caldarium RK-1. Southern-hybridization analysis combined with CHEF revealed the chromosomes on which the ftsZ gene exist. Northern-hybridization analysis indicated that the C. caldarium RK-1 ftsZ gene is transcribed as a 1.9-kb molecule, and that the transcripts specifically accumulate just before plastid division. Phylogenetic analysis indicated that C. caldarium RK-1 and other eukaryotic ftsZ genes are the descendants of cyanobacterial ftsZ genes, supporting the current agreement that FtsZ is involved in plastid division.
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the primitive red algae Cyanidium caldarium and cyanidioschyzon merolae as model system for investigating the dividing apparatus of mitochondria and plastids
BioEssays, 1998Co-Authors: Tsuneyoshi KuroiwaAbstract:The Cyanidiophyceae species Cyanidium caldarium and Cyanidioschyzon merolae have played important roles in showing the division mechanisms of mitochondria and plastids. The apparatus regulating mitochondrial and plastid divisions was formerly unknown. We first identified the division apparatus of plastids, called the plastid-dividing ring (PD ring), in C. caldarium and the division apparatus of mitochondria, called the mitochondrion-dividing ring (MD ring), in C. merolae. Eukaryotic cell division is therefore controlled by at least three dividing apparati (rings)—a contractile ring, an MD ring, and a PD ring—while bacterial division is controlled by a single bacterial contractile FtsZ ring. BioEssays20:344-354, 1998.© 1998 John Wiley & Sons, Inc.
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cytokinesis by a contractile ring in the primitive red alga Cyanidium caldarium rk 1
European Journal of Cell Biology, 1995Co-Authors: Kuninori Suzuki, T Mita, T Kawazu, Hideo Takahashi, Ryuuichi Itoh, Kyoko Toda, Tsuneyoshi KuroiwaAbstract:To better understand the mechanism of cytokinesis in eukaryotes, the behavior of the contractile ring in the two unicellular primitive red algae Cyanidioschyzon merolae and Cyanidium caldarium RK-1, which have the smallest genome size among eukaryotes, was examined by fluorescein isothiocyanate (FITC)-phalloidin fluorescence microscopy, fluorometry using a video-intensified microscope photoncounting system, transmission electron microscopy and immunoblotting techniques. Cells in each alga contained one nucleus, one mitochondrion and one chloroplast, which were aligned in that order. During cytokinesis in C. merolae, a contractile ring was not observed by fluorescence microscopy or by transmission electron microscopy. In contrast, in C. caldarium RK-1, a contractile ring appeared at the equatorial region of the dividing cells and began to contract from the side of the chloroplast. During contraction of this ring, the total fluorescent intensities due to FITC-phalloidin remained constant. Electron microscopy revealed outer and inner bands approximately 80 nm wide and 9 nm thick which ran parallel to each other just beneath the cell membrane. These bands were visible at the equator of the cell just before the initiation of cytokinesis and constricted from the pole of the chloroplast. Both bands increased in width as cleavage progressed. The inner ring consisted of a bundle of approximately 20 actin-like filaments which were arranged as a raft. In the outer ring, such fine filaments were not visible. It seems likely that the bundle of filaments, known as the contractile ring, is composed of two different elements: an inner band of actin filaments and an outer band of unknown materials.(ABSTRACT TRUNCATED AT 250 WORDS)
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Physical map of the plastid genome of the unicellular red alga Cyanidium caldarium strain RK-1.
Current Genetics, 1994Co-Authors: Niji Ohta, Shigeyuki Kawano, Tsuneyoshi KuroiwaAbstract:The physical map of the plastid genome of the unicellular red alga Cyanidium caldarium strain RK-1 was constructed. The 150-kbp genome was circular and had an inverted repeat region (IR) which contained the genes for 16 s and 23 s ribosomal RNAs, as is usually seen in most plastid genomes. Since C. caldarium is a very “primitive” alga, the results suggest that the ancestral cyanobacteria lost most of its genome as an endosymbiont comparatively early in the process of plastid formation. After that, several genes seem to have been lost from plastid genomes, step by step, during the course of evolution.
Shigeyuki Kawano - One of the best experts on this subject based on the ideXlab platform.
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Isolation, characterization, and chromosomal mapping of an ftsZ gene from the unicellular primitive red alga Cyanidium caldarium RK-1.
Current genetics, 2000Co-Authors: Manabu Takahara, Shigeyuki Kawano, Hidenori Takahashi, Sachihiro Matsunaga, Atsushi Sakai, Tsuneyoshi KuroiwaAbstract:The FtsZ protein is involved in eukaryote plastid division, but there is little information on its involvement in the plastid-dividing apparatus. To investigate the relationship between FtsZ and the plastid-dividing ring, the ftsZ gene was isolated from the unicellular primitive red alga Cyanidium caldarium RK-1. Comparison of several prokaryotic and eukaryotic FtsZ proteins shows that there are six highly conserved domains in the core region of FtsZ. To determine the chromosomal location of ftsZ, we first determined the electrophoretic karyotype of C. caldarium RK-1. Southern-hybridization analysis combined with CHEF revealed the chromosomes on which the ftsZ gene exist. Northern-hybridization analysis indicated that the C. caldarium RK-1 ftsZ gene is transcribed as a 1.9-kb molecule, and that the transcripts specifically accumulate just before plastid division. Phylogenetic analysis indicated that C. caldarium RK-1 and other eukaryotic ftsZ genes are the descendants of cyanobacterial ftsZ genes, supporting the current agreement that FtsZ is involved in plastid division.
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Physical map of the plastid genome of the unicellular red alga Cyanidium caldarium strain RK-1.
Current Genetics, 1994Co-Authors: Niji Ohta, Shigeyuki Kawano, Tsuneyoshi KuroiwaAbstract:The physical map of the plastid genome of the unicellular red alga Cyanidium caldarium strain RK-1 was constructed. The 150-kbp genome was circular and had an inverted repeat region (IR) which contained the genes for 16 s and 23 s ribosomal RNAs, as is usually seen in most plastid genomes. Since C. caldarium is a very “primitive” alga, the results suggest that the ancestral cyanobacteria lost most of its genome as an endosymbiont comparatively early in the process of plastid formation. After that, several genes seem to have been lost from plastid genomes, step by step, during the course of evolution.
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The trpA gene on the plastid genome of Cyanidium caldarium strain RK-1.
Current Genetics, 1994Co-Authors: Niji Ohta, Shigeyuki Kawano, Naoki Sato, Tsuneyoshi KuroiwaAbstract:The trpA gene (for the α subunit of tryptophan synthase) was found on the plastid genome of the “primitive” unicellular red alga Cyanidium caldarium strain RK-1. This is the first example of an actively-transcribed gene for tryptophan synthase encoded on a plastid genome. In contrast to trpA, trpB (the gene for the β subunit of tryptophan synthase) was encoded in the cell nucleus. Considering the primitive characteristics of C. caldarium, trpB must have been lost from the plastid genome before trpA.
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Plastid Genome of Cyanidium caldarium Strain RK-1 Encodes trpA
Cytologia, 1993Co-Authors: Niji Ohta, Shigeyuki Kawano, Tsuneyoshi KuroiwaAbstract:We examined the organization of organelle DNA in the two algae, Cyanidium caldarium RK-1 and C. caldrium M-8 with epifluorescence microscopy and molecular-biological techniques. The plastid nucleus (pt-nucleus, a complex of DNA and proteins) is located in the central area of the plastid in C. caldarium RK-1, while the ring-shaped pt-nucleus is located at the periphery of the petal-like plastid in C. caldarium M-8. The results suggest that C. caladarium RK-1 markedly differs from C. caldarium M-8 in an evolutionary tree.To confirm the result, we examined the fragment that contained rbcL. The trpA (the gene for the α subunit of the tryptophan synthase), which was located on the vicinity of the rbcL, was found on the plastid genome of the “primitive” unicellular red alga, C. caldarium RK-1, while the gene could not be found on the plastid genome of the C. calardium M-8 (Galdieria sulphuraria). This is the first example of typtophan synthase encoded on the plastid genome. The results suggest that the trpA gene may have relocated from the plastid genome to the cellnuclear genome for longer ago than the genes that have been considered to date to have been lost from plastid genomes in the advanced members of plants.
Niji Ohta - One of the best experts on this subject based on the ideXlab platform.
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Physical map of the plastid genome of the unicellular red alga Cyanidium caldarium strain RK-1.
Current Genetics, 1994Co-Authors: Niji Ohta, Shigeyuki Kawano, Tsuneyoshi KuroiwaAbstract:The physical map of the plastid genome of the unicellular red alga Cyanidium caldarium strain RK-1 was constructed. The 150-kbp genome was circular and had an inverted repeat region (IR) which contained the genes for 16 s and 23 s ribosomal RNAs, as is usually seen in most plastid genomes. Since C. caldarium is a very “primitive” alga, the results suggest that the ancestral cyanobacteria lost most of its genome as an endosymbiont comparatively early in the process of plastid formation. After that, several genes seem to have been lost from plastid genomes, step by step, during the course of evolution.
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comparison of ultrastructures between the ultra small eukaryote cyanidioschyzon merolae and Cyanidium caldarium
Cytologia, 1994Co-Authors: Tsuneyoshi Kuroiwa, Niji Ohta, Hidenori Takahashi, Tamotsu Kawazu, Kuninori Suzuki, Haruko KuroiwaAbstract:The behaviors of Golgi apparatus in Cyanidioschyzon merolae and Cyanidium caldarium forma A were examined as one aspect of the minimum ultrastructural characteristics of eukaryote by using a serial thin-section electron microscopic technique after rapid-freeze fixation. C. merolae cells did not contain a typical Golgi apparatus or cell wall, while C. caldarium forma A cells contained a cell wall and at least one Golgi apparatus in the cytoplasm. In C. caldarium strain forma A, some vesicles of the golgi apparatus were close to the cell wall during its formation. Therefore, the Golgi apparatus may be intimately related to the formation of the cell wall and may evolve with its formation.
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The trpA gene on the plastid genome of Cyanidium caldarium strain RK-1.
Current Genetics, 1994Co-Authors: Niji Ohta, Shigeyuki Kawano, Naoki Sato, Tsuneyoshi KuroiwaAbstract:The trpA gene (for the α subunit of tryptophan synthase) was found on the plastid genome of the “primitive” unicellular red alga Cyanidium caldarium strain RK-1. This is the first example of an actively-transcribed gene for tryptophan synthase encoded on a plastid genome. In contrast to trpA, trpB (the gene for the β subunit of tryptophan synthase) was encoded in the cell nucleus. Considering the primitive characteristics of C. caldarium, trpB must have been lost from the plastid genome before trpA.
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Plastid Genome of Cyanidium caldarium Strain RK-1 Encodes trpA
Cytologia, 1993Co-Authors: Niji Ohta, Shigeyuki Kawano, Tsuneyoshi KuroiwaAbstract:We examined the organization of organelle DNA in the two algae, Cyanidium caldarium RK-1 and C. caldrium M-8 with epifluorescence microscopy and molecular-biological techniques. The plastid nucleus (pt-nucleus, a complex of DNA and proteins) is located in the central area of the plastid in C. caldarium RK-1, while the ring-shaped pt-nucleus is located at the periphery of the petal-like plastid in C. caldarium M-8. The results suggest that C. caladarium RK-1 markedly differs from C. caldarium M-8 in an evolutionary tree.To confirm the result, we examined the fragment that contained rbcL. The trpA (the gene for the α subunit of the tryptophan synthase), which was located on the vicinity of the rbcL, was found on the plastid genome of the “primitive” unicellular red alga, C. caldarium RK-1, while the gene could not be found on the plastid genome of the C. calardium M-8 (Galdieria sulphuraria). This is the first example of typtophan synthase encoded on the plastid genome. The results suggest that the trpA gene may have relocated from the plastid genome to the cellnuclear genome for longer ago than the genes that have been considered to date to have been lost from plastid genomes in the advanced members of plants.
Isao Enami - One of the best experts on this subject based on the ideXlab platform.
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lysyl oxidase like protein secreted from an acidophilic red alga Cyanidium caldarium
Plant direct, 2018Co-Authors: Tatsuya Tomo, Akinori Okumura, Takehiro Suzuki, Mirai Okuhara, Ruriko Katayama, Noboru Isayama, Ryo Nagao, Masako Iwai, Naoshi Dohmae, Isao EnamiAbstract:Cyanidium caldarium is a primitive acidophilic red alga which grown optimally at pH 1-3. When the alga was cultured at pH 6, which is the upper limit of acidity for its survival, most of the algal cells became large cells with four endospores which did not split into daughter cells. This suggests that the alga survives in the endospore state at pH 6 to protect against nutrient uptake deficiency due to low pH gradient across the cell membranes. The alga was also found to secrete an extracellular protein specifically at pH 6. The protein was identified to be lysyl oxidase-like protein, which had been reported to be widely distributed in the animal kingdom but not yet found in the plant kingdom. In the plant kingdom, only two primitive acidophilic algae, C. caldarium and Cyanidioschyzon merolae, possess a gene encoding this protein.
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Light-induced H+ Efflux from Intact Cells of Cyanidium caldarium
2016Co-Authors: Mariko Kura-hotta, Isao EnamiAbstract:Light-induced pH changes in suspensions of an acidophilic unicellular alga, Cyanidium caldarium Geitler, were studied as a function of the pH of the medium. In the neutral pH region, alkalization of the medium due to photosynthetic CO2 uptake was observed. In the acidic pH region, illumination caused a significant decrease in the pH of the medium, indicating the efflux of H+ from the cells. Both the rate and extent of the pH decrease increased as the pH of the medium was lowered to 3.0. The H+ efflux was not affected by 3-(3',4'-dichlorophenyl)-l,l-dimethylurea, but was inhibited by phenyl-mercuric acetate. The fastest H+ efflux occurred at 45°C, whereas its extent was almost constant from 25 to 50°C. The activity decreased at temperatures above 50°C and was inactivated completely at 60°C. Its action spectrum corresponded the spectrum for chlorophyll a absorption. Results indicate that the light-induced H+ efflux is driven by photosystem I and is important in the maintenance of the intracellular pH at the functional neutral region against a steep pH gradient across the cell membrane. Key words: Acidophily — Cyanidium caldarium — H+ efflux — Light-induced pH change — pH Gradient — Proton pump
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Purification And Crystallization Of Photosystem Ii Dimer Complex From A Red Alga Cyanidium caldarium
Photosynthesis. Energy from the Sun, 2008Co-Authors: Hideyuki Adachi, Isao Enami, Takahiro Henmi, Nobuo Kamiya, Jian-ren ShenAbstract:The central part of photosystem II (PSII) is highly conserved from prokaryotic cyanobacteria to eukaryotes; however, there are some apparent differences in the extrinsic proteins involved in oxygen evolution among different organisms. So far, the crystal structure of PSII from cyanobacteria has been reported, whereas no reports have been published on the structure of any eukaryotic PSII. Red alga is one of the eukaryotic algae closely related to cyanobacteria, but its PSII differs from that of cyanobacteria in that the former contains a 20 kDa protein, a unique, fourth extrinsic protein. In order to elucidate the structure of red algal PSII and its differences with cyanobacterial PSII, we purified and crystallized PSII from an acidophilic, thermophilic red alga Cyanidium caldarium. In this study, the previously published procedure for purification of PSII from the red alga was improved, yielding a highly purified PSII dimer preparation with high oxygen-evolving activities comparable with that of thermophilic cyanobacterial PSII. We obtained three-dimensional crystals of the red algal PS II under several conditions, and characterized the crystals by X-ray diffraction. The results showed that the red algal PSII crystals had a space group of P2221, which is different from that of cyanobacterial crystals. The unit cell parameters of red algal PSII were also different from those of cyanobacterial PSII, with a and c axes longer and b axis shorter than those of cyanobacterial PSII.
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cloning and sequencing of the gene encoding the plasma membrane h atpase from an acidophilic red alga Cyanidium caldarium
Biochimica et Biophysica Acta, 1997Co-Authors: Hisataka Ohta, Hitoshi Shirakawa, Kohji Uchida, Michiteru Yoshida, Yuhsi Matuo, Isao EnamiAbstract:Abstract A cDNA containing an open reading frame encoding the putative plasma membrane H+-ATPase in an acidophilic red alga, Cyanidium caldarium, was cloned and sequenced by means of PCR and Southern hybridization based on homologous sequences of P-type ATPases found in other organisms. The cloned cDNA is 3300 bp in length, containing a 2865 bp open reading frame encoding a polypeptide of 955 amino acids which has a predicted molecular mass of 105 371. The deduced amino acid sequence was found to be more homologous to those of P-type H+-ATPases from higher plants than that from the green alga Dunaliella bioculata.©1997 Elsevier Science B.V. All rights reserved.
Etsuro Yoshimura - One of the best experts on this subject based on the ideXlab platform.
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external iron regulates polyphosphate content in the acidophilic thermophilic alga Cyanidium caldarium
Biological Trace Element Research, 2008Co-Authors: Seiji Nagasaka, Etsuro YoshimuraAbstract:Transmission electron microscopy revealed the presence of electron-dense bodies (EDB) in the cytosol of the acidophilic, thermophilic red alga Cyanidium caldarium. These bodies contain almost exclusively Fe, P, and O and can play a role in Fe storage. 31P-nuclear magnetic resonance analysis identified a sharp signal at −23.3 ppm, which was attributed to the phosphate groups of the inner portions of polyphosphate chains. From this evidence, as well as that of a previous ESR study (Nagasaka et al., BioMetals 16:465–470, 2003), it can be concluded that polyphosphates are the major anionic constituents of the EDB. Omission of Fe from the culture medium resulted in substantially decreased polyphosphate levels, demonstrating the control of cellular polyphosphate content by the Fe status of the culture medium.
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Metal metabolism in the red alga Cyanidium caldarium and its relationship to metal tolerance.
Biometals : an international journal on the role of metal ions in biology biochemistry and medicine, 2004Co-Authors: Seiji Nagasaka, Naoko K. Nishizawa, Satoshi Mori, Etsuro YoshimuraAbstract:The unicellular red alga Cyanidium caldarium is tolerant to high levels of various metal ions. Cells of this alga cultured with divalent metal ions at 5 mM contained an elevated concentration of each metal, with the highest level for Zn followed by Mn > Ni > Cu. This order is in fair agreement with the toxicity levels reported previously, with the exception of Mn, which shows a toxicity level comparable to that of Ni. Transmission electron microscopy indicated the presence of electron-dense bodies in the algal cells, and elemental analysis by energy dispersive X-ray spectrometry showed high levels of Fe and P in these bodies. Accumulation of Zn was found in these particles in Zn-treated algal cells, whereas no such deposition was found for Cu, Ni, or Mn in cells treated with the respective metals. Although trapping of Zn in the intracellular bodies may contribute to reduction of metal activity in the cells, this effect can be overcome by high intracellular levels of Zn that result in a high degree of toxicity. The correlation between intracellular concentration and toxic levels of metal ions implies that the reduced incorporation of the metals is a major detoxification mechanism in this alga.
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Evidence that electron-dense bodies in Cyanidium caldarium have an iron-storage role.
Biometals : an international journal on the role of metal ions in biology biochemistry and medicine, 2003Co-Authors: Seiji Nagasaka, Naoko K. Nishizawa, Tokuko Watanabe, Satoshi Mori, Etsuro YoshimuraAbstract:The acidophilic and thermophilic unicellular red alga, Cyanidium caldarium (Tilden) Geitler, is widely distributed in acidic hot springs. Observation by transmission electron microscopy (TEM) showed that algae grown in Allen's medium contained electron-dense bodies with diameters from 100 to 200 nm. Electron dispersive x-ray analysis indicated that the electron-dense bodies contained high levels of iron, phosphorous, and oxygen; P/Fe ratios were from 1.3 to 2.0. The electron spin resonance (ESR) spectrum of the intact C. caldarium cells showed an isotropic signal at a g value of 2.00. Density-gradient centrifugation of the cell lysate yielded a fraction that included substances showing the isotropic ESR signal. EDTA treatment of this fraction reduced the ESR signal intensity, whereas it increased a signal that is typical of Fe(III)-EDTA. The fact that the isotropic signal dominates the ESR spectrum, together with a previous finding that iron is confined to the electron-dense bodies, led us to conclude that iron in the electron-dense bodies accounts for the isotropic ESR signal. Since the intensity of the ESR signal depends on the amount of iron in the cells, the electron-dense bodies are probably iron storage sites.
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novel iron storage particles may play a role in aluminum tolerance of Cyanidium caldarium
Planta, 2002Co-Authors: Seiji Nagasaka, Naoko K. Nishizawa, Satoshi Mori, Kenichi Satake, Takashi Negishi, Etsuro YoshimuraAbstract:Cyanidium caldarium (Tilden) Geitler, a unicellular red alga, has extraordinarily high aluminum (Al) tolerance. Algal cells cultured in the presence or absence of Al were subjected to transmission electron microscopy and energy dispersive X-ray analysis. Substantial changes to the thylakoid lumens were observed for the algal cells cultured in medium containing 200 mM Al, while other organelles were largely unaffected. Several spherical electron-dense bodies were found in the cytoplasm near the nucleus of both of the control and Al-treated cells. Although high levels of Fe and P were found in the bodies of control cells, immunocytochemical and morphological analysis data did not match the criteria established for Fe-accumulating substances like ferritin and phytate. In addition to these elements, Al was found in the bodies of the Al-treated cells. These results suggest that the electron-dense bodies function as an Fe-storage site under normal culture conditions, and that sequestration of Al in these bodies contributes to the high Al tolerance exhibited by C. caldarium.
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mechanism of aluminium tolerance in Cyanidium caldarium
Hydrobiologia, 2000Co-Authors: Etsuro Yoshimura, Seiji Nagasaka, Kenichi Satake, Satoshi MoriAbstract:Cyanidium caldarium, an acidophilic, thermophilic red alga, specifically tolerates Al. The tolerance increases at lower culture temperatures. The intracellular Al concentration is kept at low levels, especially when the cells are cultured at lower temperatures. Lower Al incorporation accounts for the Al tolerance in this alga. Fe incorporation antagonizes the Al incorporation, implying that Fe transporters incorporate Al ions. Treatment with an uncoupler, carbonylcyanide m-chlorophenylhydrazone, increases the intracellular concentration of Al. These results support the hypothesis that Al ions taken up by the algal cells are exported by an energy-dependent mechanism.
