The Experts below are selected from a list of 3420 Experts worldwide ranked by ideXlab platform
Tomoyoshi Ikawa - One of the best experts on this subject based on the ideXlab platform.
-
co localization of chloroplast dna and ribulose 1 5 bisphosphate carboxylase oxygenase in the so called Pyrenoid of the siphonous green alga caulerpa lentillifera caulerpales chlorophyta
Phycologia, 1996Co-Authors: Shinichi Miyamura, Terumitsu Hori, Toshihide Ohya, Takeshi Tohma, Tomoyoshi IkawaAbstract:The Pyrenoid of the siphonous green alga Caulerpa lentillifera J. Agardh contains DNA. The Pyrenoid was separated from the cell to examine whether it is a true Pyrenoid. Chloroplast DNA (ct-DNA) wa...
-
Co-localization of chloroplast DNA and ribulose-1,5-bisphosphate carboxylase/oxygenase in the so-called Pyrenoid of the siphonous green alga Caulerpa lentillifera (Caulerpales, Chlorophyta)
Phycologia, 1996Co-Authors: Shinichi Miyamura, Terumitsu Hori, Toshihide Ohya, Takeshi Tohma, Tomoyoshi IkawaAbstract:The Pyrenoid of the siphonous green alga Caulerpa lentillifera J. Agardh contains DNA. The Pyrenoid was separated from the cell to examine whether it is a true Pyrenoid. Chloroplast DNA (ct-DNA) wa...
Terumitsu Hori - One of the best experts on this subject based on the ideXlab platform.
-
co localization of chloroplast dna and ribulose 1 5 bisphosphate carboxylase oxygenase in the so called Pyrenoid of the siphonous green alga caulerpa lentillifera caulerpales chlorophyta
Phycologia, 1996Co-Authors: Shinichi Miyamura, Terumitsu Hori, Toshihide Ohya, Takeshi Tohma, Tomoyoshi IkawaAbstract:The Pyrenoid of the siphonous green alga Caulerpa lentillifera J. Agardh contains DNA. The Pyrenoid was separated from the cell to examine whether it is a true Pyrenoid. Chloroplast DNA (ct-DNA) wa...
-
Co-localization of chloroplast DNA and ribulose-1,5-bisphosphate carboxylase/oxygenase in the so-called Pyrenoid of the siphonous green alga Caulerpa lentillifera (Caulerpales, Chlorophyta)
Phycologia, 1996Co-Authors: Shinichi Miyamura, Terumitsu Hori, Toshihide Ohya, Takeshi Tohma, Tomoyoshi IkawaAbstract:The Pyrenoid of the siphonous green alga Caulerpa lentillifera J. Agardh contains DNA. The Pyrenoid was separated from the cell to examine whether it is a true Pyrenoid. Chloroplast DNA (ct-DNA) wa...
-
DNA IS PRESENT IN THE Pyrenoid CORE OF THE SIPHONOUS GREEN ALGAE OF THE GENUS CAULERPA AND YELLOW-GREEN ALGAE OF THE GENUS PSEUDODICHOTOMOSIPHON
Protoplasma, 1991Co-Authors: S. Miyamura, Terumitsu HoriAbstract:The Pyrenoids of a number of siphonous green and yellow-green algae have been examined for the presence of chloroplast DNA (chloroplast nucleoids). We have found a conspicuous localization of chloroplast DNA in the Pyrenoid core ofCaulerpa lentillifera andC. fergusonii (siphonous green algae), andPseudodichotomosiphon constrictus (a siphonous yellow-green alga) using fluorescence microscopy after staining with the DNA specific fluorochrome 4′,6-diamidino-2-phenylindole (DAPI).
Taizo Motomura - One of the best experts on this subject based on the ideXlab platform.
-
Re‐examination of ultrastructures of the stellate chloroplast organization in brown algae: Structure and development of Pyrenoids
Phycological Research, 2007Co-Authors: Atsuko Tanaka, Chikako Nagasato, Shinya Uwai, Taizo Motomura, Hiroshi KawaiAbstract:SUMMARY Some taxa of brown algae have a so-called ‘stellate’ chloroplast arrangement composed of multiple chloroplasts arranged in a stellate configuration, or else a single chloroplast with radiating lobes. The fine structures of chloroplasts and Pyrenoids have been studied, but the details of their membrane configurations as well as Pyrenoid ontogeny have not been well understood. The ultrastructure of the single stellate chloroplast in Splachnidium rugosum and Scytothamnus australis were re-examined in the present study, as well as the stellate arrangement of chloroplasts in Asteronema ferruginea and Asterocladon interjectum, using freeze-substitution fixation. It was confirmed that the chloroplast envelope invaginated into the Pyrenoid in Splachnidium rugosum, Scytothamnus australis and Asteronema ferruginea, but chloroplast endoplasmic reticulum (CER) remained on the surface of the chloroplast. The space between the invaginated chloroplast envelope and CER was filled with electron-dense material. In Asteronema ferruginea, CER surrounding each Pyrenoid was closely appressed to the neighboring CER over the Pyrenoids, so that the chloroplasts formed a stellate configuration; however, in the apical cells chloroplasts formed two or more loose groups, or were completely dispersed. The Pyrenoids of Asterocladon interjectum did not have any invagination of the chloroplast envelope, but a unique membranous sac surrounded the Pyrenoid complex and occasionally other organelles (e.g. mitochondria). Immunolocalization of β-1,3-glucans showed that the membranous sac in Asterocladon interjectum did not contain photosynthetic products such as chrysolaminaran. Observations in the dividing cells of Splachnidium rugosum and Scytothamnus australis indicated that the Pyrenoid in the center of the chloroplast enlarged and divided into two before or during chloroplast division.
-
Pyrenoid FORMATION ASSOCIATED WITH THE CELL CYCLE IN THE BROWN ALGA, SCYTOSIPHON LOMENTARIA (SCYTOSIPHONALES, PHAEOPHYCEAE)1
Journal of Phycology, 2003Co-Authors: Chikako Nagasato, Hiroshi Kawai, Shinya Yoshikawa, Masakane Yamashita, Taizo MotomuraAbstract:Vegetative cells of the brown alga Scytosiphon lomentaria (Lyngbye) Link characteristically have only one chloroplast with a prominent protruding Pyrenoid, whereas zygotes have both paternal and maternal chloroplasts. In zygotes, before cell and chloroplast division, each chloroplast has an old and a new Pyrenoid. In this study, we raised a polyclonal antibody to RUBISCO and examined the distribution of RUBISCO by immunofluorescence microscopy, focusing on new Pyrenoid formation in vegetative cells of gametophytes and zygotes in Scytosiphon. In interphase, only one old Pyrenoid was positively indicated by anti-RUBISCO antibody in vegetative cells of gametophytes. From mid-S phase, small fluorescence aggregates reflecting RUBISCO localization started to appear at stroma positions other than adjacent to the old protruding Pyrenoid. The fluorescent spots eventually coalesced into a protrusion into the adjacent cytoplasm. We also used inhibitors to clarify the relationship between the cell cycle and new Pyrenoid formation, using zygotes after fertilization. When DNA replication was blocked by aphidicolin, new Pyrenoid formation was also inhibited. Washing out aphidicolin permitted new Pyrenoid formation with the progression of the cell cycle. When mitosis was prolonged by nocodazole, which disrupted the spindle microtubules, the fluorescent masses indicating RUBISCO localization continued to increase when compared with Pyrenoid formation in untreated zygotes. During treatment with chloramphenicol, mitosis and cytokinesis were completed. However, there was no occurrence of new RUBISCO localization within the chloroplast stroma beyond the old Pyrenoid. From these observations, it seems clear that new Pyrenoid formation in the brown alga Scytosiphon depends on the cell cycle.
-
NEW Pyrenoid FORMATION IN THE BROWN ALGA, SCYTOSIPHON LOMENTARIA (SCYTOSIPHONALES, PHAEOPHYCEAE)1
Journal of Phycology, 2002Co-Authors: Chikako Nagasato, Taizo MotomuraAbstract:The Scytosiphon lomentaria (Lyngbye) Link cell characteristically has only one chloroplast with a prominent protruding Pyrenoid. We observed the appearance of a new Pyrenoid in each chloroplast during first mitosis in zygotes of S. lomentaria, using the freeze substitution technique. At first, a Pyrenoid matrix appeared within the outermost stroma, in which thylakoid triplets and ribosomes were absent. At this time, the surface of this part remained smooth. The old Pyrenoid was covered with a Pyrenoid cap on the cytoplasmic side, whereas there was no Pyrenoid cap on the new Pyrenoid before protrusion. Irregularly shaped membranous sacs containing fine granular materials associated with the cytoplasmic side of the new Pyrenoid. The sacs fused with each other and changed conformation and finally transformed into the Pyrenoid cap. The new Pyrenoid gradually protruded toward the cytoplasm, and the new Pyrenoid cap became curved along the surface of Pyrenoid. Cytokinesis occurred, and each chloroplast had two prominent protruding Pyrenoids in two-celled zygotes. We examined immunolocalization of β-1,3-glucans within the Pyrenoid cap with a monoclonal antibody, using EM. Gold particles indicating localization of β-1,3-glucans were detected in vacuoles but never in the Pyrenoid cap. This observation suggests that the Pyrenoid cap in brown algae contains no photosynthetic products such as polysaccharide.
Shinichi Miyamura - One of the best experts on this subject based on the ideXlab platform.
-
co localization of chloroplast dna and ribulose 1 5 bisphosphate carboxylase oxygenase in the so called Pyrenoid of the siphonous green alga caulerpa lentillifera caulerpales chlorophyta
Phycologia, 1996Co-Authors: Shinichi Miyamura, Terumitsu Hori, Toshihide Ohya, Takeshi Tohma, Tomoyoshi IkawaAbstract:The Pyrenoid of the siphonous green alga Caulerpa lentillifera J. Agardh contains DNA. The Pyrenoid was separated from the cell to examine whether it is a true Pyrenoid. Chloroplast DNA (ct-DNA) wa...
-
Co-localization of chloroplast DNA and ribulose-1,5-bisphosphate carboxylase/oxygenase in the so-called Pyrenoid of the siphonous green alga Caulerpa lentillifera (Caulerpales, Chlorophyta)
Phycologia, 1996Co-Authors: Shinichi Miyamura, Terumitsu Hori, Toshihide Ohya, Takeshi Tohma, Tomoyoshi IkawaAbstract:The Pyrenoid of the siphonous green alga Caulerpa lentillifera J. Agardh contains DNA. The Pyrenoid was separated from the cell to examine whether it is a true Pyrenoid. Chloroplast DNA (ct-DNA) wa...
Chikako Nagasato - One of the best experts on this subject based on the ideXlab platform.
-
thylakoid luminal θ carbonic anhydrase critical for growth and photosynthesis in the marine diatom phaeodactylum tricornutum
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Sae Kikutani, Chikako Nagasato, Kensuke Nakajima, Yoshinori Tsuji, Ai Miyatake, Yusuke MatsudaAbstract:The algal Pyrenoid is a large plastid body, where the majority of the CO2-fixing enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) resides, and it is proposed to be the hub of the algal CO2-concentrating mechanism (CCM) and CO2 fixation. The thylakoid membrane is often in close proximity to or penetrates the Pyrenoid itself, implying there is a functional cooperation between the Pyrenoid and thylakoid. Here, GFP tagging and immunolocalization analyses revealed that a previously unidentified protein, Pt43233, is targeted to the lumen of the Pyrenoid-penetrating thylakoid in the marine diatom Phaeodactylum tricornutum. The recombinant Pt43233 produced in Escherichia coli cells had both carbonic anhydrase (CA) and esterase activities. Furthermore, a Pt43233:GFP-fusion protein immunoprecipitated from P. tricornutum cells displayed a greater specific CA activity than detected for the purified recombinant protein. In an RNAi-generated Pt43233 knockdown mutant grown in atmospheric CO2 levels, photosynthetic dissolved inorganic carbon (DIC) affinity was decreased and growth was constantly retarded; in contrast, overexpression of Pt43233:GFP yielded a slightly greater photosynthetic DIC affinity. The discovery of a θ-type CA localized to the thylakoid lumen, with an essential role in photosynthetic efficiency and growth, strongly suggests the existence of a common role for the thylakoid-luminal CA with respect to the function of diverse algal Pyrenoids.
-
Re‐examination of ultrastructures of the stellate chloroplast organization in brown algae: Structure and development of Pyrenoids
Phycological Research, 2007Co-Authors: Atsuko Tanaka, Chikako Nagasato, Shinya Uwai, Taizo Motomura, Hiroshi KawaiAbstract:SUMMARY Some taxa of brown algae have a so-called ‘stellate’ chloroplast arrangement composed of multiple chloroplasts arranged in a stellate configuration, or else a single chloroplast with radiating lobes. The fine structures of chloroplasts and Pyrenoids have been studied, but the details of their membrane configurations as well as Pyrenoid ontogeny have not been well understood. The ultrastructure of the single stellate chloroplast in Splachnidium rugosum and Scytothamnus australis were re-examined in the present study, as well as the stellate arrangement of chloroplasts in Asteronema ferruginea and Asterocladon interjectum, using freeze-substitution fixation. It was confirmed that the chloroplast envelope invaginated into the Pyrenoid in Splachnidium rugosum, Scytothamnus australis and Asteronema ferruginea, but chloroplast endoplasmic reticulum (CER) remained on the surface of the chloroplast. The space between the invaginated chloroplast envelope and CER was filled with electron-dense material. In Asteronema ferruginea, CER surrounding each Pyrenoid was closely appressed to the neighboring CER over the Pyrenoids, so that the chloroplasts formed a stellate configuration; however, in the apical cells chloroplasts formed two or more loose groups, or were completely dispersed. The Pyrenoids of Asterocladon interjectum did not have any invagination of the chloroplast envelope, but a unique membranous sac surrounded the Pyrenoid complex and occasionally other organelles (e.g. mitochondria). Immunolocalization of β-1,3-glucans showed that the membranous sac in Asterocladon interjectum did not contain photosynthetic products such as chrysolaminaran. Observations in the dividing cells of Splachnidium rugosum and Scytothamnus australis indicated that the Pyrenoid in the center of the chloroplast enlarged and divided into two before or during chloroplast division.
-
Pyrenoid FORMATION ASSOCIATED WITH THE CELL CYCLE IN THE BROWN ALGA, SCYTOSIPHON LOMENTARIA (SCYTOSIPHONALES, PHAEOPHYCEAE)1
Journal of Phycology, 2003Co-Authors: Chikako Nagasato, Hiroshi Kawai, Shinya Yoshikawa, Masakane Yamashita, Taizo MotomuraAbstract:Vegetative cells of the brown alga Scytosiphon lomentaria (Lyngbye) Link characteristically have only one chloroplast with a prominent protruding Pyrenoid, whereas zygotes have both paternal and maternal chloroplasts. In zygotes, before cell and chloroplast division, each chloroplast has an old and a new Pyrenoid. In this study, we raised a polyclonal antibody to RUBISCO and examined the distribution of RUBISCO by immunofluorescence microscopy, focusing on new Pyrenoid formation in vegetative cells of gametophytes and zygotes in Scytosiphon. In interphase, only one old Pyrenoid was positively indicated by anti-RUBISCO antibody in vegetative cells of gametophytes. From mid-S phase, small fluorescence aggregates reflecting RUBISCO localization started to appear at stroma positions other than adjacent to the old protruding Pyrenoid. The fluorescent spots eventually coalesced into a protrusion into the adjacent cytoplasm. We also used inhibitors to clarify the relationship between the cell cycle and new Pyrenoid formation, using zygotes after fertilization. When DNA replication was blocked by aphidicolin, new Pyrenoid formation was also inhibited. Washing out aphidicolin permitted new Pyrenoid formation with the progression of the cell cycle. When mitosis was prolonged by nocodazole, which disrupted the spindle microtubules, the fluorescent masses indicating RUBISCO localization continued to increase when compared with Pyrenoid formation in untreated zygotes. During treatment with chloramphenicol, mitosis and cytokinesis were completed. However, there was no occurrence of new RUBISCO localization within the chloroplast stroma beyond the old Pyrenoid. From these observations, it seems clear that new Pyrenoid formation in the brown alga Scytosiphon depends on the cell cycle.
-
NEW Pyrenoid FORMATION IN THE BROWN ALGA, SCYTOSIPHON LOMENTARIA (SCYTOSIPHONALES, PHAEOPHYCEAE)1
Journal of Phycology, 2002Co-Authors: Chikako Nagasato, Taizo MotomuraAbstract:The Scytosiphon lomentaria (Lyngbye) Link cell characteristically has only one chloroplast with a prominent protruding Pyrenoid. We observed the appearance of a new Pyrenoid in each chloroplast during first mitosis in zygotes of S. lomentaria, using the freeze substitution technique. At first, a Pyrenoid matrix appeared within the outermost stroma, in which thylakoid triplets and ribosomes were absent. At this time, the surface of this part remained smooth. The old Pyrenoid was covered with a Pyrenoid cap on the cytoplasmic side, whereas there was no Pyrenoid cap on the new Pyrenoid before protrusion. Irregularly shaped membranous sacs containing fine granular materials associated with the cytoplasmic side of the new Pyrenoid. The sacs fused with each other and changed conformation and finally transformed into the Pyrenoid cap. The new Pyrenoid gradually protruded toward the cytoplasm, and the new Pyrenoid cap became curved along the surface of Pyrenoid. Cytokinesis occurred, and each chloroplast had two prominent protruding Pyrenoids in two-celled zygotes. We examined immunolocalization of β-1,3-glucans within the Pyrenoid cap with a monoclonal antibody, using EM. Gold particles indicating localization of β-1,3-glucans were detected in vacuoles but never in the Pyrenoid cap. This observation suggests that the Pyrenoid cap in brown algae contains no photosynthetic products such as polysaccharide.
