The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described. The types of reproduction and...The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described. The types of reproduction and early development as well as the morphology, of egg and larva in different ascidian species were compared. Styela canopus is oviparous. Its egg, 230.4 similar to 336.0 mum in diameter, is equipped with extraembryonic cell layers measured 43.2 similar to 63.0 mum thick. The early development of Styela canopus is typical urodele development, including fertilization, cleavage, gastrulation, tadpole in membrane, tadpole, initiating metamorphosis and juvenile. The tadpole of Styela canopus, with a length of 0.6 similar to 0. 9 mm, consists of trunk and tail. There are obvious notochord, ocellus and adhesive papillae in the tadpole. Under the water temperature of (25 +/- 0-5) degreesC and the salinity of 27.0, the larva was hatched after 9.5 similar to 11.0 h since the fertilization.展开更多
Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,esp...Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,especially benthic species lacking behavioral choices to select optimal habitats,have to utilize well-established strategies such as the antioxidant defense system(ADS)to ensure their survival.Therefore,understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges.Here we conducted a com-parative analysis of the physiological and transcriptional responses based on the ADS during two rounds of'hypersalinity-recovery'challenges in two model congeneric invasive ascidians,Ciona robusta and C.savignyi.Our results demonstrated that C.savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level,while C.robusta demonstrated heightened responses at the transcriptional level.We observed distinct transcriptional responses,particularly in the utilization of two superoxide dismutase(SOD)isoforms.Both Ciona species developed physiological stress memory with elevated total SOD(T-SOD)and glutathione(GSH)responses,while only C.robusta demonstrated transcriptional stress memory.The regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species.These findings support the'context-dependent stress memory hypothesis',emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges.Our results enhance our understanding of the mechanisms of environmental challenge manage-ment in marine species,particularly those related to the ADS.展开更多
The ascidian Styela clava is an ecologically important species that is distributed along coastal regions worldwide.It has a long history as a model animal for evolutionary and developmental biology research owing to i...The ascidian Styela clava is an ecologically important species that is distributed along coastal regions worldwide.It has a long history as a model animal for evolutionary and developmental biology research owing to its phylogenetic position between vertebrates and invertebrates,and its classical mosaic expression patterns.However,the standard developmental atlas and protocols and tools for molecular manipulation of this organism are inadequate.In this study,we established a standard developmental table and provided a web-based digital image resource for S.clava embryogenesis at each developmental stage from fertilized eggs to hatching larvae by utilizing confocal laser microscopy and 3D reconstruction images.It takes around 10 h for fertilized eggs to develop into swimming larvae and 20–30 min to complete the tail regression processes at the metamorphic stage.We observed that the notochord cells in S.clava embryos did not produce an extracellular lumen like Ciona robusta,but showed polarized elongation behaviors,providing us an ideal comparative model to study tissue morphogenesis.In addition,we established a chemical-washing procedure to remove the chorion easily from the fertilized eggs.Based on the dechorionation technique,we further realized transgenic manipulation by electroporation and successfully applied tissue-specific fluorescent labeling in S.clava embryos.Our work provides a standard imaging atlas and powerful genetic tools for investigating embryogenesis and evolution using S.clava as a model organism.展开更多
为了研究LINC(Linker of nucleoskeleton and cytoskeleton)复合体相关基因KASH(Klarsicht/Anc/Syne-1)和SUN(Sad1/UNC84)在海鞘(Ciona robusta)细胞核位置决定中的角色和作用,本研究鉴定并分别克隆了海鞘LINC复合体中编码2种Cr_KASH蛋...为了研究LINC(Linker of nucleoskeleton and cytoskeleton)复合体相关基因KASH(Klarsicht/Anc/Syne-1)和SUN(Sad1/UNC84)在海鞘(Ciona robusta)细胞核位置决定中的角色和作用,本研究鉴定并分别克隆了海鞘LINC复合体中编码2种Cr_KASH蛋白和2种Cr_SUN蛋白的基因。荧光定量PCR方法分析了上述4个基因在海鞘胚胎各个时期的表达量,发现在胚胎发育的尾芽延伸期,几种基因的表达量均有不同程度的提高。原位杂交方法揭示Cr_KASH1、Cr_SUN1和Cr_SUN2特异表达在海鞘胚胎的脊索组织中,而Cr_KASH2则特异表达在肌肉组织。在NIH/3T3细胞中的亚细胞定位分析证实,上述LINC复合体蛋白与不同的细胞骨架交联。通过破坏细胞骨架微丝和微管蛋白的聚合发现会影响KASH和SUN在细胞中的定位和结构,暗示海鞘LINC复合体成分和细胞质骨架蛋白协同作用调控细胞核的形态和位置。本文研究结果表明,在海鞘不同胚胎发育阶段和不同组织中,细胞核骨架或许通过不同LINC蛋白组分与细胞骨架结合影响细胞核的行为。展开更多
文摘The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described. The types of reproduction and early development as well as the morphology, of egg and larva in different ascidian species were compared. Styela canopus is oviparous. Its egg, 230.4 similar to 336.0 mum in diameter, is equipped with extraembryonic cell layers measured 43.2 similar to 63.0 mum thick. The early development of Styela canopus is typical urodele development, including fertilization, cleavage, gastrulation, tadpole in membrane, tadpole, initiating metamorphosis and juvenile. The tadpole of Styela canopus, with a length of 0.6 similar to 0. 9 mm, consists of trunk and tail. There are obvious notochord, ocellus and adhesive papillae in the tadpole. Under the water temperature of (25 +/- 0-5) degreesC and the salinity of 27.0, the larva was hatched after 9.5 similar to 11.0 h since the fertilization.
基金supported by the National Natural Science Foundation of China(Grant No.32061143012 to A.Z.,32101352 to X.H.).
文摘Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,especially benthic species lacking behavioral choices to select optimal habitats,have to utilize well-established strategies such as the antioxidant defense system(ADS)to ensure their survival.Therefore,understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges.Here we conducted a com-parative analysis of the physiological and transcriptional responses based on the ADS during two rounds of'hypersalinity-recovery'challenges in two model congeneric invasive ascidians,Ciona robusta and C.savignyi.Our results demonstrated that C.savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level,while C.robusta demonstrated heightened responses at the transcriptional level.We observed distinct transcriptional responses,particularly in the utilization of two superoxide dismutase(SOD)isoforms.Both Ciona species developed physiological stress memory with elevated total SOD(T-SOD)and glutathione(GSH)responses,while only C.robusta demonstrated transcriptional stress memory.The regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species.These findings support the'context-dependent stress memory hypothesis',emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges.Our results enhance our understanding of the mechanisms of environmental challenge manage-ment in marine species,particularly those related to the ADS.
基金supported by the National Key Research and Development Program of China(2022YFC2601304,2022YFC2601302)the Science&Technology Innovation Project of Laoshan Laboratory(LSKJ202203002)+2 种基金the Taishan Scholar Program of Shandong Province,China(to BD)Database Construction was supported by the Research Institute of Marine Invertebrates(IKU2021-02)the Keio University Doctorate Student Grant-in-Aid Program from Ushioda Memorial Fund and JSPS KAKENHI Grant Number JP 22J22628,and Keio Gijuku Education with a Research-Adjusted Budget to TTS.
文摘The ascidian Styela clava is an ecologically important species that is distributed along coastal regions worldwide.It has a long history as a model animal for evolutionary and developmental biology research owing to its phylogenetic position between vertebrates and invertebrates,and its classical mosaic expression patterns.However,the standard developmental atlas and protocols and tools for molecular manipulation of this organism are inadequate.In this study,we established a standard developmental table and provided a web-based digital image resource for S.clava embryogenesis at each developmental stage from fertilized eggs to hatching larvae by utilizing confocal laser microscopy and 3D reconstruction images.It takes around 10 h for fertilized eggs to develop into swimming larvae and 20–30 min to complete the tail regression processes at the metamorphic stage.We observed that the notochord cells in S.clava embryos did not produce an extracellular lumen like Ciona robusta,but showed polarized elongation behaviors,providing us an ideal comparative model to study tissue morphogenesis.In addition,we established a chemical-washing procedure to remove the chorion easily from the fertilized eggs.Based on the dechorionation technique,we further realized transgenic manipulation by electroporation and successfully applied tissue-specific fluorescent labeling in S.clava embryos.Our work provides a standard imaging atlas and powerful genetic tools for investigating embryogenesis and evolution using S.clava as a model organism.
文摘为了研究LINC(Linker of nucleoskeleton and cytoskeleton)复合体相关基因KASH(Klarsicht/Anc/Syne-1)和SUN(Sad1/UNC84)在海鞘(Ciona robusta)细胞核位置决定中的角色和作用,本研究鉴定并分别克隆了海鞘LINC复合体中编码2种Cr_KASH蛋白和2种Cr_SUN蛋白的基因。荧光定量PCR方法分析了上述4个基因在海鞘胚胎各个时期的表达量,发现在胚胎发育的尾芽延伸期,几种基因的表达量均有不同程度的提高。原位杂交方法揭示Cr_KASH1、Cr_SUN1和Cr_SUN2特异表达在海鞘胚胎的脊索组织中,而Cr_KASH2则特异表达在肌肉组织。在NIH/3T3细胞中的亚细胞定位分析证实,上述LINC复合体蛋白与不同的细胞骨架交联。通过破坏细胞骨架微丝和微管蛋白的聚合发现会影响KASH和SUN在细胞中的定位和结构,暗示海鞘LINC复合体成分和细胞质骨架蛋白协同作用调控细胞核的形态和位置。本文研究结果表明,在海鞘不同胚胎发育阶段和不同组织中,细胞核骨架或许通过不同LINC蛋白组分与细胞骨架结合影响细胞核的行为。
