The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Maho Niwa - One of the best experts on this subject based on the ideXlab platform.
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the er stress surveillance ersu pathway regulates Daughter Cell er protein aggregate inheritance
eLife, 2015Co-Authors: Francisco Pina, Maho NiwaAbstract:Many species of yeast form new Cells by a process known as budding in which a small Daughter Cell ‘buds’ out of a larger mother Cell. Mothers can only produce a limited number of buds before they die of old age. However, age is reset in the Daughters to ensure that they are fully rejuvenated when born. Therefore, the mother Cell needs to prevent the factors that cause aging and Cell damage from entering the Daughter. Inside Cells, proteins are made and folded correctly in a structure called the endoplasmic reticulum. If proteins are not folded properly, they are normally rapidly destroyed. However, if a Cell requires lots of proteins to be made quickly, this can sometimes overwhelm and ‘stress’ the endoplasmic reticulum. When this occurs, proteins start misfolding and clump up to form toxic aggregates, some of which collect inside the endoplasmic reticulum. The Endoplasmic Reticulum Stress Surveillance (ERSU) pathway monitors the health of the endoplasmic reticulum and prevents ‘stressed’ endoplasmic reticulum from entering Daughter Cells, which can cause them to die. By visualizing the endoplasmic reticulum and the aggregates contained within it during budding in the yeast species Saccharomyces cerevisiae, Pina and Niwa have now found that the ERSU pathway can also prevent these aggregates from entering Daughter Cells. However, if the ERSU pathway is not switched on—as may be the case if the level of endoplasmic reticulum stress is very low—then aggregates can enter the Daughter Cells. This is in contrast to protein aggregates that form elsewhere in the Cell, which are normally always kept inside the mother Cell due to their damaging effects. These results suggest that the ERSU pathway is responsible for preventing protein aggregates in the endoplasmic reticulum from entering Daughter Cells, but only does so when these aggregates stress the endoplasmic reticulum. Future research will aim to identify how the ERSU pathway senses protein aggregates and prevents the transmission of damaged endoplasmic reticulum.
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The ER Stress Surveillance (ERSU) pathway regulates Daughter Cell ER protein aggregate inheritance
eLife, 2015Co-Authors: Francisco Pina, Maho NiwaAbstract:Stress induced by cytoplasmic protein aggregates can have deleterious consequences for the Cell, contributing to neurodegeneration and other diseases. Protein aggregates are also formed within the endoplasmic reticulum (ER), although the fate of ER protein aggregates, specifically during Cell division, is not well understood. By simultaneous visualization of both the ER itself and ER protein aggregates, we found that ER protein aggregates that induce ER stress are retained in the mother Cell by activation of the ER Stress Surveillance (ERSU) pathway, which prevents inheritance of stressed ER. In contrast, under conditions of normal ER inheritance, ER protein aggregates can enter the Daughter Cell. Thus, whereas cytoplasmic protein aggregates are retained in the mother Cell to protect the functional capacity of Daughter Cells, the fate of ER protein aggregates is determined by whether or not they activate the ERSU pathway to impede transmission of the cortical ER during the Cell cycle.
Ken-ichiro Ishida - One of the best experts on this subject based on the ideXlab platform.
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gymnochlora dimorpha sp nov a chlorarachniophyte with unique Daughter Cell behaviour
Phycologia, 2011Co-Authors: Astuko Kudo, Ken-ichiro IshidaAbstract:Abstract Ota S., Kudo A. and Ishida K.-I. 2011. Gymnochlora dimorpha sp. nov., a chlorarachniophyte with unique Daughter Cell behaviour. Phycologia 50: 317–326. DOI: 10.2216/09-102.1 A new chlorarachniophyte species, Gymnochlora dimorpha sp. nov., was described. This new species was isolated from an enrichment preculture of Padina sp. collected from a subtidal coral reef zone in Republic of Palau. The new strain, P314, was characterized by light and electron microscopy in the present study. Under the culture conditions used here, the amoeboid stage was dominant. Two types of amoeboid Cells were found in the cultures: motile and flattened nonmotile (sessile) Cells. The motile Cells typically multiplied via binary Cell division. The sessile Cells were always present in the cultures, but they never became dominant under the culture conditions. Time-lapse video microscopic observations revealed that after Cell division of a sessile Cell, one Daughter Cell became motile, while the other remained sessile. Accor...
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Gymnochlora dimorpha sp nov., a chlorarachniophyte with unique Daughter Cell behaviour
Phycologia, 2011Co-Authors: Shuhei Ota, Astuko Kudo, Ken-ichiro IshidaAbstract:A new chlorarachniophyte species, Gymnochlora dimorpha sp. nov., was described. This new species was isolated from an enrichment preculture of Padina sp. collected from a subtidal coral reef zone in Republic of Palau. The new strain, P314, was characterized by light and electron microscopy in the present study. Under the culture conditions used here, the amoeboid stage was dominant. Two types of amoeboid Cells were found in the cultures: motile and flattened nonmotile (sessile) Cells: The motile Cells typically multiplied via binary Cell division. The sessile Cells were always present in the cultures, but they never became dominant under the culture conditions. Time-lapse video microscopic observations revealed that after Cell division of a sessile Cell, one Daughter Cell became motile, while the other remained sessile. According to ultrastructural characteristics of the pyrenoids and nucleomorphs, the new chlorarachniophyte strain belongs to the genus Gynmochlora. However, P314 differed from G. stellata, the only hitherto known species of that genus, by forming flattened sessile Cells in culture and having smaller Cell dimensions (7-14 mu m). Therefore, P314 is described here as a new species of Gymnochlora. This conclusion is supported by previously reported 18S rDNA phylogenies of chlorarachniophytes. The genus Gymnochlora as defined by morphology accorded with the molecular phylogenies.
Francisco Pina - One of the best experts on this subject based on the ideXlab platform.
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the er stress surveillance ersu pathway regulates Daughter Cell er protein aggregate inheritance
eLife, 2015Co-Authors: Francisco Pina, Maho NiwaAbstract:Many species of yeast form new Cells by a process known as budding in which a small Daughter Cell ‘buds’ out of a larger mother Cell. Mothers can only produce a limited number of buds before they die of old age. However, age is reset in the Daughters to ensure that they are fully rejuvenated when born. Therefore, the mother Cell needs to prevent the factors that cause aging and Cell damage from entering the Daughter. Inside Cells, proteins are made and folded correctly in a structure called the endoplasmic reticulum. If proteins are not folded properly, they are normally rapidly destroyed. However, if a Cell requires lots of proteins to be made quickly, this can sometimes overwhelm and ‘stress’ the endoplasmic reticulum. When this occurs, proteins start misfolding and clump up to form toxic aggregates, some of which collect inside the endoplasmic reticulum. The Endoplasmic Reticulum Stress Surveillance (ERSU) pathway monitors the health of the endoplasmic reticulum and prevents ‘stressed’ endoplasmic reticulum from entering Daughter Cells, which can cause them to die. By visualizing the endoplasmic reticulum and the aggregates contained within it during budding in the yeast species Saccharomyces cerevisiae, Pina and Niwa have now found that the ERSU pathway can also prevent these aggregates from entering Daughter Cells. However, if the ERSU pathway is not switched on—as may be the case if the level of endoplasmic reticulum stress is very low—then aggregates can enter the Daughter Cells. This is in contrast to protein aggregates that form elsewhere in the Cell, which are normally always kept inside the mother Cell due to their damaging effects. These results suggest that the ERSU pathway is responsible for preventing protein aggregates in the endoplasmic reticulum from entering Daughter Cells, but only does so when these aggregates stress the endoplasmic reticulum. Future research will aim to identify how the ERSU pathway senses protein aggregates and prevents the transmission of damaged endoplasmic reticulum.
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The ER Stress Surveillance (ERSU) pathway regulates Daughter Cell ER protein aggregate inheritance
eLife, 2015Co-Authors: Francisco Pina, Maho NiwaAbstract:Stress induced by cytoplasmic protein aggregates can have deleterious consequences for the Cell, contributing to neurodegeneration and other diseases. Protein aggregates are also formed within the endoplasmic reticulum (ER), although the fate of ER protein aggregates, specifically during Cell division, is not well understood. By simultaneous visualization of both the ER itself and ER protein aggregates, we found that ER protein aggregates that induce ER stress are retained in the mother Cell by activation of the ER Stress Surveillance (ERSU) pathway, which prevents inheritance of stressed ER. In contrast, under conditions of normal ER inheritance, ER protein aggregates can enter the Daughter Cell. Thus, whereas cytoplasmic protein aggregates are retained in the mother Cell to protect the functional capacity of Daughter Cells, the fate of ER protein aggregates is determined by whether or not they activate the ERSU pathway to impede transmission of the cortical ER during the Cell cycle.
Astuko Kudo - One of the best experts on this subject based on the ideXlab platform.
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gymnochlora dimorpha sp nov a chlorarachniophyte with unique Daughter Cell behaviour
Phycologia, 2011Co-Authors: Astuko Kudo, Ken-ichiro IshidaAbstract:Abstract Ota S., Kudo A. and Ishida K.-I. 2011. Gymnochlora dimorpha sp. nov., a chlorarachniophyte with unique Daughter Cell behaviour. Phycologia 50: 317–326. DOI: 10.2216/09-102.1 A new chlorarachniophyte species, Gymnochlora dimorpha sp. nov., was described. This new species was isolated from an enrichment preculture of Padina sp. collected from a subtidal coral reef zone in Republic of Palau. The new strain, P314, was characterized by light and electron microscopy in the present study. Under the culture conditions used here, the amoeboid stage was dominant. Two types of amoeboid Cells were found in the cultures: motile and flattened nonmotile (sessile) Cells. The motile Cells typically multiplied via binary Cell division. The sessile Cells were always present in the cultures, but they never became dominant under the culture conditions. Time-lapse video microscopic observations revealed that after Cell division of a sessile Cell, one Daughter Cell became motile, while the other remained sessile. Accor...
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Gymnochlora dimorpha sp nov., a chlorarachniophyte with unique Daughter Cell behaviour
Phycologia, 2011Co-Authors: Shuhei Ota, Astuko Kudo, Ken-ichiro IshidaAbstract:A new chlorarachniophyte species, Gymnochlora dimorpha sp. nov., was described. This new species was isolated from an enrichment preculture of Padina sp. collected from a subtidal coral reef zone in Republic of Palau. The new strain, P314, was characterized by light and electron microscopy in the present study. Under the culture conditions used here, the amoeboid stage was dominant. Two types of amoeboid Cells were found in the cultures: motile and flattened nonmotile (sessile) Cells: The motile Cells typically multiplied via binary Cell division. The sessile Cells were always present in the cultures, but they never became dominant under the culture conditions. Time-lapse video microscopic observations revealed that after Cell division of a sessile Cell, one Daughter Cell became motile, while the other remained sessile. According to ultrastructural characteristics of the pyrenoids and nucleomorphs, the new chlorarachniophyte strain belongs to the genus Gynmochlora. However, P314 differed from G. stellata, the only hitherto known species of that genus, by forming flattened sessile Cells in culture and having smaller Cell dimensions (7-14 mu m). Therefore, P314 is described here as a new species of Gymnochlora. This conclusion is supported by previously reported 18S rDNA phylogenies of chlorarachniophytes. The genus Gymnochlora as defined by morphology accorded with the molecular phylogenies.
Tobias Dörr - One of the best experts on this subject based on the ideXlab platform.
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Lytic transglycosylases RlpA and MltC assist in Vibrio cholerae Daughter Cell separation
Molecular microbiology, 2019Co-Authors: Anna I Weaver, Valeria Jiménez-ruiz, Srikar Tallavajhala, Brett Ransegnola, Kimberly Q Wong, Tobias DörrAbstract:The Cell wall is a crucial structural feature in the vast majority of bacteria and comprises a covalently closed network of peptidoglycan (PG) strands. While PG synthesis is important for survival under many conditions, the Cell wall is also a dynamic structure, undergoing degradation and remodeling by 'autolysins', enzymes that break down PG. Cell division, for example, requires extensive PG remodeling, especially during separation of Daughter Cells, which depends heavily upon the activity of amidases. However, in Vibrio cholerae, we demonstrate that amidase activity alone is insufficient for Daughter Cell separation and that lytic transglycosylases RlpA and MltC both contribute to this process. MltC and RlpA both localize to the septum and are functionally redundant under normal laboratory conditions; however, only RlpA can support normal Cell separation in low-salt media. The division-specific activity of lytic transglycosylases has implications for the local structure of septal PG, suggesting that there may be glycan bridges between Daughter Cells that cannot be resolved by amidases. We propose that lytic transglycosylases at the septum cleave PG strands that are crosslinked beyond the reach of the highly regulated activity of the amidase and clear PG debris that may block the completion of outer membrane invagination.
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Lytic transglycosylases RlpA and MltC assist in Vibrio cholerae Daughter Cell separation
2019Co-Authors: Anna I Weaver, Valeria Jiménez-ruiz, Srikar Tallavajhala, Brett Ransegnola, Kimberly Q Wong, Tobias DörrAbstract:ABSTRACT The Cell wall is a crucial structural feature in the vast majority of bacteria and comprises a rigid, covalently closed, mesh-like network of peptidoglycan (PG) strands. While PG synthesis is important for bacterial survival under many conditions, the Cell wall is also a dynamic structure, undergoing degradation and remodeling by so-called “autolysins”, enzymes that break bonds in the PG network. Cell division, for example, requires extensive PG remodeling and separation of Daughter Cells, which depends primarily upon the activity of amidases. However, in V. cholerae, we have found that amidase activity alone is insufficient for Daughter Cell separation and that the lytic transglycosylases RlpA and MltC both contribute to this process. MltC and RlpA both localize to the septum and are functionally redundant under normal laboratory conditions; however, only RlpA can support normal Cell separation in low salt media. The division-specific activity of lytic transglycosylases has implications for the local structure of septal PG, suggesting that there may be glycan bridges between Daughter Cells that cannot be resolved by amidases. We propose that lytic transglycosylases at the septum serve as a back-up mechanism to cleave rare, stochastically produced PG strands that are crosslinked beyond the reach of the highly spatio-temporally limited activity of the amidase and to clear PG debris that may block the completion of outer-membrane invagination.
