The Experts below are selected from a list of 78 Experts worldwide ranked by ideXlab platform
Leonid L Moroz - One of the best experts on this subject based on the ideXlab platform.
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endogenous thyroid hormone Synthesis in facultative planktotrophic larvae of the sand dollar clypeaster rosaceus implications for the evolutionary loss of larval feeding
Evolution & Development, 2006Co-Authors: Andreas Heyland, Adam M Reitzel, David A Price, Leonid L MorozAbstract:SUMMARY Critical roles of hormones in metamorphic life history transitions are well documented in amphibians, lampreys, insects, and many plant species. Recent evidence suggests that thyroid hormones (TH) or TH-like compounds can regulate development to metamorphosisin echinoids (sea urchins, sand dollars, and their relatives). Moreover, previous research has provided evidence for endogenous hormone Synthesis in both feeding and nonfeeding echinoderm larvae. However, the mechanisms for endogenous Synthesis remain largely unknown. Here, we show that facultatively planktotrophic larvae (larvae that reach metamorphosis in the absence of food but have the ability to feed) from the subtropical sea biscuit Clypeaster rosaceus can synthesize Thyroxine endogenously from incorporated iodine (I 125 ). When treated with the goitrogen thiourea (a peroxidase inhibitor), iodine incorporation, Thyroxine Synthesis, and metamorphosis are all blocked in a dose-dependent manner. The inhibitory effect on metamorphosis can be rescued by administration of exogenous Thyroxine. Finally, we demonstrate that thiourea induces morphological changes in feeding structures comparable to the phenotypic plastic response of larval structures to low food conditions, further supporting a signaling role of Thyroxine in regulating larval morphogenesis and phenotypic plasticity. We conclude that upregulation of endogenous hormone Synthesis might have been associated with the evolution of nonfeeding development, subsequently leading to morphological changes characteristic of nonfeeding development.
Andreas Heyland - One of the best experts on this subject based on the ideXlab platform.
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endogenous thyroid hormone Synthesis in facultative planktotrophic larvae of the sand dollar clypeaster rosaceus implications for the evolutionary loss of larval feeding
Evolution & Development, 2006Co-Authors: Andreas Heyland, Adam M Reitzel, David A Price, Leonid L MorozAbstract:SUMMARY Critical roles of hormones in metamorphic life history transitions are well documented in amphibians, lampreys, insects, and many plant species. Recent evidence suggests that thyroid hormones (TH) or TH-like compounds can regulate development to metamorphosisin echinoids (sea urchins, sand dollars, and their relatives). Moreover, previous research has provided evidence for endogenous hormone Synthesis in both feeding and nonfeeding echinoderm larvae. However, the mechanisms for endogenous Synthesis remain largely unknown. Here, we show that facultatively planktotrophic larvae (larvae that reach metamorphosis in the absence of food but have the ability to feed) from the subtropical sea biscuit Clypeaster rosaceus can synthesize Thyroxine endogenously from incorporated iodine (I 125 ). When treated with the goitrogen thiourea (a peroxidase inhibitor), iodine incorporation, Thyroxine Synthesis, and metamorphosis are all blocked in a dose-dependent manner. The inhibitory effect on metamorphosis can be rescued by administration of exogenous Thyroxine. Finally, we demonstrate that thiourea induces morphological changes in feeding structures comparable to the phenotypic plastic response of larval structures to low food conditions, further supporting a signaling role of Thyroxine in regulating larval morphogenesis and phenotypic plasticity. We conclude that upregulation of endogenous hormone Synthesis might have been associated with the evolution of nonfeeding development, subsequently leading to morphological changes characteristic of nonfeeding development.
Bernard Mallet - One of the best experts on this subject based on the ideXlab platform.
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dityrosine bridge formation and thyroid hormone Synthesis are tightly linked and are both dependent on n glycans
FEBS Letters, 1996Co-Authors: Nathalie Baudry, Pierrejean Lejeune, Patricia Niccoli, Liliane Vinet, Pierre Carayon, Bernard MalletAbstract:Formation of dityrosine bridges is a ubiquitous process mainly attributed to oxidative stress leading to protein degradation and cellular damages. Here we show that dityrosine formation is involved in a physiological process, thyroid hormone Synthesis, and is strictly dependent on structural characteristics, namely N-glycans, presented by the protein acting as the prothyroid hormone. We used two isoforms of the N-terminal thyroid hormone forming domain (NTD) of human thyroglobulin: one without N-glycan (19 kDa isoform) and the other with high mannose type structures (25 kDa isoform). Both isoforms were able to form iodotyrosines after in vitro iodination. However, iodotyrosine coupling to form Thyroxine did not occur with the unglycosylated 19 kDa NTD. In contrast, the 25 kDa isoform formed Thyroxine. Strikingly, Thyroxine Synthesis was accompanied by dimerization of the 25 kDa isoform and formation of a dityrosine bridge; none of this was observed with the 19 kDa isoform. Taken as a whole, our results indicate that dimerization through dityrosine bridging accompanies and could have a role in thyroid hormone Synthesis.
Nathalie Baudry - One of the best experts on this subject based on the ideXlab platform.
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dityrosine bridge formation and thyroid hormone Synthesis are tightly linked and are both dependent on n glycans
FEBS Letters, 1996Co-Authors: Nathalie Baudry, Pierrejean Lejeune, Patricia Niccoli, Liliane Vinet, Pierre Carayon, Bernard MalletAbstract:Formation of dityrosine bridges is a ubiquitous process mainly attributed to oxidative stress leading to protein degradation and cellular damages. Here we show that dityrosine formation is involved in a physiological process, thyroid hormone Synthesis, and is strictly dependent on structural characteristics, namely N-glycans, presented by the protein acting as the prothyroid hormone. We used two isoforms of the N-terminal thyroid hormone forming domain (NTD) of human thyroglobulin: one without N-glycan (19 kDa isoform) and the other with high mannose type structures (25 kDa isoform). Both isoforms were able to form iodotyrosines after in vitro iodination. However, iodotyrosine coupling to form Thyroxine did not occur with the unglycosylated 19 kDa NTD. In contrast, the 25 kDa isoform formed Thyroxine. Strikingly, Thyroxine Synthesis was accompanied by dimerization of the 25 kDa isoform and formation of a dityrosine bridge; none of this was observed with the 19 kDa isoform. Taken as a whole, our results indicate that dimerization through dityrosine bridging accompanies and could have a role in thyroid hormone Synthesis.
Patricia Niccoli - One of the best experts on this subject based on the ideXlab platform.
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dityrosine bridge formation and thyroid hormone Synthesis are tightly linked and are both dependent on n glycans
FEBS Letters, 1996Co-Authors: Nathalie Baudry, Pierrejean Lejeune, Patricia Niccoli, Liliane Vinet, Pierre Carayon, Bernard MalletAbstract:Formation of dityrosine bridges is a ubiquitous process mainly attributed to oxidative stress leading to protein degradation and cellular damages. Here we show that dityrosine formation is involved in a physiological process, thyroid hormone Synthesis, and is strictly dependent on structural characteristics, namely N-glycans, presented by the protein acting as the prothyroid hormone. We used two isoforms of the N-terminal thyroid hormone forming domain (NTD) of human thyroglobulin: one without N-glycan (19 kDa isoform) and the other with high mannose type structures (25 kDa isoform). Both isoforms were able to form iodotyrosines after in vitro iodination. However, iodotyrosine coupling to form Thyroxine did not occur with the unglycosylated 19 kDa NTD. In contrast, the 25 kDa isoform formed Thyroxine. Strikingly, Thyroxine Synthesis was accompanied by dimerization of the 25 kDa isoform and formation of a dityrosine bridge; none of this was observed with the 19 kDa isoform. Taken as a whole, our results indicate that dimerization through dityrosine bridging accompanies and could have a role in thyroid hormone Synthesis.