[Objective] Pollen mother cell miosis and male gametophyte development of pumpkin were observed in this study, to provide some cytological basis for pumpkin anther or microspore culture. [Method] Ehrlich＇s hematoxyli...[Objective] Pollen mother cell miosis and male gametophyte development of pumpkin were observed in this study, to provide some cytological basis for pumpkin anther or microspore culture. [Method] Ehrlich＇s hematoxylin staining-methyl salicylate clearing technique was used for observation and research of the variation of cell structure and chromosomal behavior during pollen mother cell miosis and male gametophyte development of ‘Tianhong＇ pumpkin. [Result] The meiosis in pollen moth- er cells of pumpkin was simultaneous cytokinesis. In the process of nuclear division, nuclear membrane and nucleolus of pumpkin pollen mother cells gradually disappeared in the metaphase I and reappeared in telophase I , phragmoplast formed between the two generated crescent-shaped nuclei without cell wall, the phragmoplast gradually disappeared in the metaphase II and reappeared in telophase II. Phragmoplast spread outward from the center of spindle during the second division was connected with that formed on the central interface of two nuclei during the first division, cell wall of microspores generated from periphery to center. Most of the tetrads contained four sub-cells while a few contained extra small cells. During the period of uniuclete microspore at periphery, the single nucleolus split into 2-3 or more small nucleoli, mature pollen grain was two-celled. Mononucleate pollen cells were mostly appeared in the flower buds with length of 1.0-2.0 cm, which could be used as an important indicator to collect materials for anther or microspore culture. [Conclusion] This study laid the foundation for research of the cytogenetics of pumpkin.展开更多
[Objective] This study aimed to study the genes affecting division mode in the early embryonic development of Arabidopsis thaliana.[Method] Two T-DNA insertion mutants were isolated from the mutant library of A.thalia...[Objective] This study aimed to study the genes affecting division mode in the early embryonic development of Arabidopsis thaliana.[Method] Two T-DNA insertion mutants were isolated from the mutant library of A.thaliana inserted by T-DNA,and the embryonic development was reflected by phenotypes.[Result] Genomic PCR-WALKING analyses demonstrated that T-DNA insertion sites were in 5＇ non-coding region and promoter region of gene At4g20360 which encodes Rab GTPase RABE1b,and the two mutants were named as Atrabe1b-1 and Atrabe1b-2,respectively.Microscopic analysis on mutants revealed that there was an abnormal cell division pattern in early globular stage of embryonic development.In addition,RT-PCR analysis showed that gene At4g20360 was constitutively expressed in A.thaliana.[Conclusion] Gene At4g20360 affected the division pattern of early embryonic development in A.thaliana,and encoded protein GTPase RABE1b which may play an important role in cell division during the embryonic development of A.thaliana.展开更多
Animal cells require extrinsic cues for growth, proliferation and survival. The propagation of Drosophila imaginal disc cells in vitro, for example, requires the supplementation of fly extract, the composition of whic...Animal cells require extrinsic cues for growth, proliferation and survival. The propagation of Drosophila imaginal disc cells in vitro, for example, requires the supplementation of fly extract, the composition of which remains largely undefined. Here I report the biochemical purification of iron-loaded ferritin as an active ingredient of fly extract that is required for promoting the growth of clone 8 imaginal disc cells. Consistent with an essential role for iron- loaded ferritin in cultured cells, overexpression of ferritin or addition of iron in a nutrient-poor diet increases animal viability and body weight, promotes cell proliferation, and shortens the duration of postembryonic development. Conversely, overexpression of dominant-negative ferritin or addition of iron chelator causes the opposite effects. Fer- ritin mutant flies arrest development at the first-instar larval stage with a severe starvation phenotype reminiscent of that seen in starved larvae. I conclude that iron-loaded ferritin acts as an essential mitogen for cell proliferation and postembryonic development in Drosophila by maintaining iron homeostasis and antagonizing starvation response.展开更多
Documenting the sex and sexual reproduction of the microalgae is very difficult, as most of the results are based on the microscopic observation that can be heavily influenced by genetic, physiological and environment...Documenting the sex and sexual reproduction of the microalgae is very difficult, as most of the results are based on the microscopic observation that can be heavily influenced by genetic, physiological and environmental conditions. Understanding the reproduction strategy of some microalgae is required to breed them in large scale culture industry. Instead of direct observation of sex and sexual reproduction under microscope, the whole set or the majority of core meiosis genes may evidence the sex and sexual reproduction in the unicellular algae, as the meiosis is necessary for maintaining the genomic stability and the advantages of genetic recombination. So far, the available genome sequences and bioinformatic tools （in this study, homolog searching and phylogenetic analysis） allow us to propose that at least 20 core meiosis genes （among them 〉6 must be meiosis specific） are enough for an alga to maintain its sexual reproduction. According to this assumption and the genome sequences, it is possible that sexual reproduction was carried out by Micromonas pusilla and Cyanidiosehyzon merolae, while asexual reproduction was adopted by Bigelowiella natans, Guillardia theta, Nannochloropsis gaditana, N. oeeanica, Chlorella variablis, Phaeodactylum tricornutum and Thalassiosira pseu- donana. This understanding will facilitate the breeding trials of some economic microalgae （e.g., N. gaditana, N. oceanica, C. vari- ablis and P. tricornutum）. However, the reproduction strategies of these microalgae need to be proved by further biological experiments.展开更多
Protein kinase inhibitor 6-DMAP was used to explore the effect of protein phosphorylation on germinal vesicle breakdown(GVBD) and chromatin/chromosome behavior of mousc oocytes at different stages .Protein phosphoryl...Protein kinase inhibitor 6-DMAP was used to explore the effect of protein phosphorylation on germinal vesicle breakdown(GVBD) and chromatin/chromosome behavior of mousc oocytes at different stages .Protein phosphorylation induced by 6-DMAP-sensitive protein kinases was not required for GVBD 2 hrs after culture. 6-DMAP stimulated transition to interphase in oocytes after GVBD and inhibited extrusion of the first polar body(PB1) and the second polar body(PB2). This drug also induced the reformation of nucleus in metaphase II(M II) oocytes spontaneously,without the release of cortical granules(CGs), a result that is different from the conclusion obtained before.展开更多
Erythropoiesis is a process during which multipotential hematopoietic stem cells proliferate, differentiate and eventually form mature erythrocytes. Interestingly, unlike most cell types, an important feature of eryth...Erythropoiesis is a process during which multipotential hematopoietic stem cells proliferate, differentiate and eventually form mature erythrocytes. Interestingly, unlike most cell types, an important feature of erythropoiesis is that following each mitosis the daughter cells are morphologically and functionally different from the parent cell from which they are derived, demonstrating the need to study erythropoiesis in a stage-specific manner. This has been impossible until recently due to lack of methods for isolating erythroid cells at each distinct developmental stage. This review summarizes recent advances in the development of methods for isolating both murine and human erythroid cells and their applications. These methods provide powerful means for studying normal and impaired erythropoiesis associated with hematological disorders.展开更多
Aurora kinases have become a hot topic for research as they have been found to play an important role in various stages of mitotic cell division and to participate in malignant conversions of tumors. The participation...Aurora kinases have become a hot topic for research as they have been found to play an important role in various stages of mitotic cell division and to participate in malignant conversions of tumors. The participation of Aurora kinases in the regulation of oocyte meiosis has been recently reported, but their participation in mammalian early embryonic development remained unclear. The object of our study was to establish the spatio-temporal expression pattern of Aurora kinase B (AURKB) in mouse zygotes during the first cleavage, to reveal its functions in the early development of mouse zygotes, and to define the involvement of AURKB in mitogen-activated protein kinase (MAPK) signaling. Our results showed that in mouse zygotes AURKB expression increased in G1 phase and peaked in M phase. AURKB protein distribution was found to be in association with nuclei and distributed throughout the cytoplasm in a cell cycle-dependent manner. Functional disruption of AURKB resulted in abnormal division phenotypes or mitotic impairments. U0126, a specific mitogen-activated protein kinase kinase (MEK) inhibitor, caused significantly altered morphologies of early embryos together with a decrease in protein expression and kinase activity of AURKB. Our results indicated that the activity of AURKB was required for regulating multiple stages of mitotic progression in the early development of mouse zygotes and was correlated with the activation of the MAPK pathway.展开更多
基金Supported by Project of Jiangsu Provincial Department of Education (JHZD06-7)Qing Lan Project of Colleges and Universities in Jiangsu Province (2008 No.30)~~
文摘[Objective] Pollen mother cell miosis and male gametophyte development of pumpkin were observed in this study, to provide some cytological basis for pumpkin anther or microspore culture. [Method] Ehrlich＇s hematoxylin staining-methyl salicylate clearing technique was used for observation and research of the variation of cell structure and chromosomal behavior during pollen mother cell miosis and male gametophyte development of ‘Tianhong＇ pumpkin. [Result] The meiosis in pollen moth- er cells of pumpkin was simultaneous cytokinesis. In the process of nuclear division, nuclear membrane and nucleolus of pumpkin pollen mother cells gradually disappeared in the metaphase I and reappeared in telophase I , phragmoplast formed between the two generated crescent-shaped nuclei without cell wall, the phragmoplast gradually disappeared in the metaphase II and reappeared in telophase II. Phragmoplast spread outward from the center of spindle during the second division was connected with that formed on the central interface of two nuclei during the first division, cell wall of microspores generated from periphery to center. Most of the tetrads contained four sub-cells while a few contained extra small cells. During the period of uniuclete microspore at periphery, the single nucleolus split into 2-3 or more small nucleoli, mature pollen grain was two-celled. Mononucleate pollen cells were mostly appeared in the flower buds with length of 1.0-2.0 cm, which could be used as an important indicator to collect materials for anther or microspore culture. [Conclusion] This study laid the foundation for research of the cytogenetics of pumpkin.
基金Supported by the National Natural Science Foundation of China(31071077)~~
文摘[Objective] This study aimed to study the genes affecting division mode in the early embryonic development of Arabidopsis thaliana.[Method] Two T-DNA insertion mutants were isolated from the mutant library of A.thaliana inserted by T-DNA,and the embryonic development was reflected by phenotypes.[Result] Genomic PCR-WALKING analyses demonstrated that T-DNA insertion sites were in 5＇ non-coding region and promoter region of gene At4g20360 which encodes Rab GTPase RABE1b,and the two mutants were named as Atrabe1b-1 and Atrabe1b-2,respectively.Microscopic analysis on mutants revealed that there was an abnormal cell division pattern in early globular stage of embryonic development.In addition,RT-PCR analysis showed that gene At4g20360 was constitutively expressed in A.thaliana.[Conclusion] Gene At4g20360 affected the division pattern of early embryonic development in A.thaliana,and encoded protein GTPase RABE1b which may play an important role in cell division during the embryonic development of A.thaliana.
文摘Animal cells require extrinsic cues for growth, proliferation and survival. The propagation of Drosophila imaginal disc cells in vitro, for example, requires the supplementation of fly extract, the composition of which remains largely undefined. Here I report the biochemical purification of iron-loaded ferritin as an active ingredient of fly extract that is required for promoting the growth of clone 8 imaginal disc cells. Consistent with an essential role for iron- loaded ferritin in cultured cells, overexpression of ferritin or addition of iron in a nutrient-poor diet increases animal viability and body weight, promotes cell proliferation, and shortens the duration of postembryonic development. Conversely, overexpression of dominant-negative ferritin or addition of iron chelator causes the opposite effects. Fer- ritin mutant flies arrest development at the first-instar larval stage with a severe starvation phenotype reminiscent of that seen in starved larvae. I conclude that iron-loaded ferritin acts as an essential mitogen for cell proliferation and postembryonic development in Drosophila by maintaining iron homeostasis and antagonizing starvation response.
基金financially supported by National Science and Technology Supporting Program of China (2011BAD14B01)National Natural Science Foundation of China (31270408)Key Laborotary of Marine Bioactive Substance of State Oceanic Administration of China, The First Institute of Oceanography
文摘Documenting the sex and sexual reproduction of the microalgae is very difficult, as most of the results are based on the microscopic observation that can be heavily influenced by genetic, physiological and environmental conditions. Understanding the reproduction strategy of some microalgae is required to breed them in large scale culture industry. Instead of direct observation of sex and sexual reproduction under microscope, the whole set or the majority of core meiosis genes may evidence the sex and sexual reproduction in the unicellular algae, as the meiosis is necessary for maintaining the genomic stability and the advantages of genetic recombination. So far, the available genome sequences and bioinformatic tools （in this study, homolog searching and phylogenetic analysis） allow us to propose that at least 20 core meiosis genes （among them 〉6 must be meiosis specific） are enough for an alga to maintain its sexual reproduction. According to this assumption and the genome sequences, it is possible that sexual reproduction was carried out by Micromonas pusilla and Cyanidiosehyzon merolae, while asexual reproduction was adopted by Bigelowiella natans, Guillardia theta, Nannochloropsis gaditana, N. oeeanica, Chlorella variablis, Phaeodactylum tricornutum and Thalassiosira pseu- donana. This understanding will facilitate the breeding trials of some economic microalgae （e.g., N. gaditana, N. oceanica, C. vari- ablis and P. tricornutum）. However, the reproduction strategies of these microalgae need to be proved by further biological experiments.
文摘Protein kinase inhibitor 6-DMAP was used to explore the effect of protein phosphorylation on germinal vesicle breakdown(GVBD) and chromatin/chromosome behavior of mousc oocytes at different stages .Protein phosphorylation induced by 6-DMAP-sensitive protein kinases was not required for GVBD 2 hrs after culture. 6-DMAP stimulated transition to interphase in oocytes after GVBD and inhibited extrusion of the first polar body(PB1) and the second polar body(PB2). This drug also induced the reformation of nucleus in metaphase II(M II) oocytes spontaneously,without the release of cortical granules(CGs), a result that is different from the conclusion obtained before.
基金supported by grants from the National Natural Science Foundation of China(814703628117190581272187)
文摘Erythropoiesis is a process during which multipotential hematopoietic stem cells proliferate, differentiate and eventually form mature erythrocytes. Interestingly, unlike most cell types, an important feature of erythropoiesis is that following each mitosis the daughter cells are morphologically and functionally different from the parent cell from which they are derived, demonstrating the need to study erythropoiesis in a stage-specific manner. This has been impossible until recently due to lack of methods for isolating erythroid cells at each distinct developmental stage. This review summarizes recent advances in the development of methods for isolating both murine and human erythroid cells and their applications. These methods provide powerful means for studying normal and impaired erythropoiesis associated with hematological disorders.
基金supported by the National Natural Science Foundation of China (Grant No. 81070527)
文摘Aurora kinases have become a hot topic for research as they have been found to play an important role in various stages of mitotic cell division and to participate in malignant conversions of tumors. The participation of Aurora kinases in the regulation of oocyte meiosis has been recently reported, but their participation in mammalian early embryonic development remained unclear. The object of our study was to establish the spatio-temporal expression pattern of Aurora kinase B (AURKB) in mouse zygotes during the first cleavage, to reveal its functions in the early development of mouse zygotes, and to define the involvement of AURKB in mitogen-activated protein kinase (MAPK) signaling. Our results showed that in mouse zygotes AURKB expression increased in G1 phase and peaked in M phase. AURKB protein distribution was found to be in association with nuclei and distributed throughout the cytoplasm in a cell cycle-dependent manner. Functional disruption of AURKB resulted in abnormal division phenotypes or mitotic impairments. U0126, a specific mitogen-activated protein kinase kinase (MEK) inhibitor, caused significantly altered morphologies of early embryos together with a decrease in protein expression and kinase activity of AURKB. Our results indicated that the activity of AURKB was required for regulating multiple stages of mitotic progression in the early development of mouse zygotes and was correlated with the activation of the MAPK pathway.
