The effects of ultradry storage on the activity of ATPase and fluidity of plasma membrane in Chinese cabbage (Brassica pekinensis (Lour.) Rupr.) and elm ( Ulmus pumila L.) seeds were investigated. The results indicate...The effects of ultradry storage on the activity of ATPase and fluidity of plasma membrane in Chinese cabbage (Brassica pekinensis (Lour.) Rupr.) and elm ( Ulmus pumila L.) seeds were investigated. The results indicated that no significant differences in the activity of ATPase and the micro- viscosity of plasma membrane of ultradried (UD) seeds could be found as compared to the control seeds stored under -20 degreesC, although there was a little adverse effect on the seeds with extreme dehydration. The results were consistent with higher vigor level of UD seeds. This implied that ultradry seed storage could protect the integrity of the membrane, maintain its physiological function and improve the storability of seeds. The relationship between sugar and desiccation tolerance of UD seeds was analysed using the HPLC. The results showed that the ratio of reducing to nonreducing sugar was lower in UD seeds than that in control. The content of sucrose and stachyose in elm and Chinese cabbage UD seeds was related to their desiccation tolerance, while no stachyose was detected in corn (Zea mays L.) seeds. This could be one of the reasons for its sensitivity to desiccation.展开更多
Endothelial cells (TEC_3 cells) derived from mouse embryonic stem (ES) cells were used as seed cells to construct blood vessels. Tissue engineered blood vessels were made by seeding 8 × 10~6 smooth muscle cells (...Endothelial cells (TEC_3 cells) derived from mouse embryonic stem (ES) cells were used as seed cells to construct blood vessels. Tissue engineered blood vessels were made by seeding 8 × 10~6 smooth muscle cells (SMCs) obtained from rabbit arteries onto a sheet of nonwoven polyglycolic acid (PGA) fibers, which was used as a biodegradable polymer scaffold. After being cultured in DMEM medium for 7 days in vitro, SMCs grew well on the PGA fibers, and the cell-PGA sheet was then wrapped around a silicon tube, and implanted subcutaneously into nude mice. After 6～8 weeks, the silicon tube was replaced with another silicon tube in smaller diameter, and then the TEC_3 cells (endothelial cells differentiated from mouse ES cells) were injected inside the engineered vessel tube as the test group. In the control group only culture medium was injected. Five days later, the engineered vessels were harvested for gross observation, histological and immunohistochemical analysis. The preliminary results demonstrated that the SMC-PGA construct could form a tubular structure in 6～8 weeks and PGA fibers were completely degraded. Histological and immunohistochemical analysis of the newly formed tissue revealed a typical blood vessel structure, including a lining of endothelial cells (ECs) on the lumimal surface and the presence of SMC and collagen in the wall. No EC lining was found in the tubes of control group. Therefore, the ECs differentiated from mouse ES cells can serve as seed cells for endothelium lining in tissue engineered blood vessels.展开更多
AIM： To isolate and identify the biological characteristics of human colon cancer stem cells （SW1116 cells） and further study their proteome. METHODS： SW1116 cells were isolated and cultured with a serum-free medi...AIM： To isolate and identify the biological characteristics of human colon cancer stem cells （SW1116 cells） and further study their proteome. METHODS： SW1116 cells were isolated and cultured with a serum-free medium （SFM）. Sphere formation was assayed to observe the formation of colon cancer stem cell spheres. SW1116 cells were inoculated into a serum-containing medium for observing their differentiation characteristics. Proliferation curve and cross-resistance of SWl116 cells to different drugs were detected by MTT. Percentage of SP cells in SW1116 cells was detected with Hoechst33342 staining. Telomerase activity in SW1116cells was checked by polymerase chain reaction （PCR）-enzyme linked immunosorbent assay. Expressions of stem cell relevant genes and proteins were detected by reverse transcription-PCR and Western blot, respectively. Total protein was isolated from SW1116 cells by two-dimensional gel electrophoresis （2-DE） and differentially expressed proteins were identified by tandem mass spectrometry （MALDI-TOF/TOF）. RESULTS： The isolated SW1116 cells presented as spheroid and suspension growths in SFM with a strong self-renewal, proliferation, differentiation and drug-resistance ability. The percentage of SP cells in SW1116 cells was 38.9%. The SW1116 cells co-expressed the CD133 and CD29 proteins. The telomerase activity in SW1116 cells was increased. The expressions of different stem cell relevant genes and proteins were detected. The proteomic analysis showed that the 26 protein spots were differently expressed in SW1116 cells and 10 protein spots were identified as ubiquitin fusion- degradation l-like protein, nuclear chloride channel protein, tubulin 13, Raichu404X, stratifin, F-actin cap- ping protein α-1 subunit, eukaryotic translation elongation factor 1 delta isoform 2, hypothetical protein, glyceraldehyde-3-phosphate dehydrogenase and guanine nucleotide binding protein 13 polypeptide 2-like 1, respectively. CONCLUSION： SW1116 cells are biologically characterized by self-renewal, proliferation and differentiation, and the differently expressed proteins in SW1116 cells may be essential for isolating cancer stem cells.展开更多
The evidences of three-body and four-body bound states have been reported in a series of very recent experiments with ultracold atoms.Here we study coherent creation of polyatomic molecules via a generalized atom-mole...The evidences of three-body and four-body bound states have been reported in a series of very recent experiments with ultracold atoms.Here we study coherent creation of polyatomic molecules via a generalized atom-molecule dark-state technique.By keeping the intermediate trimer or tetramer state essentially unpopulated,the constructive quantum two-channel interference is shown to play an important role in,e.g.coherent atom-pentamer conversion at ultracold temperature.展开更多
According to the study on the oil-gas source rocks in China for ten years,in connection with the microscopic, submicroscopic levels, the authors used the microscope photometry together with transmission electronic mic...According to the study on the oil-gas source rocks in China for ten years,in connection with the microscopic, submicroscopic levels, the authors used the microscope photometry together with transmission electronic microscopy, scanning electronic microscopy and proposed a new classification for sedimentary organic matters.展开更多
采用自主设计的高压挤压小试装置,将城市混合生活垃圾分为干、湿两种组分。分析其性质表明:在20 MPa和40 MPa挤压压力下,干组分含水率低于30%,热值从2 778 k J/kg分别提升至14 503,11 659 k J/kg。湿组分性质与混合垃圾中的厨余组分相近...采用自主设计的高压挤压小试装置,将城市混合生活垃圾分为干、湿两种组分。分析其性质表明:在20 MPa和40 MPa挤压压力下,干组分含水率低于30%,热值从2 778 k J/kg分别提升至14 503,11 659 k J/kg。湿组分性质与混合垃圾中的厨余组分相近,易腐成分含量高,可采用厌氧消化处理回收生物质能。采用高压挤压技术作为预处理手段,垃圾能源最大可回收量达5 340 k J/kg,相对直接焚烧提高近90%。高压挤压技术作为预处理手段,可有效提升城市混合生活垃圾的处理效率和能源回收效率。展开更多
Objective： To differentiate rat adipose tissue-derived mesenchymal stem cells （ADSCs） into cells with a nucleus pulposus-like phenotype in vitro, so as to lay a foundation for the cell-based transplantation therapy...Objective： To differentiate rat adipose tissue-derived mesenchymal stem cells （ADSCs） into cells with a nucleus pulposus-like phenotype in vitro, so as to lay a foundation for the cell-based transplantation therapy of degenerated intervertebral discs. Methods： Rat ADSCs were isolated only from the subcutaneous inguinal region and purified by limited dilution. ADSCs of the third passages were analyzed by fluorescence activated cell sorter （FACS） to detect the cell surface markers （Sca-1, CD44, CD45, CDI lb）. To induce ADSCs to- wards a nucleus pulposus-like phenotype, ADSCs were immobilized in 3-dimensional alginate hydrogels and cultured in an inducing medium containing transforming growth factor-beta1 （TGF- β1） under hypoxia （2% O2）, while control groups under normoxia （21% O2） in alginate beads in medium with or without the presence of TGF-β 1. Semiquantitative reverse transcription polymerase chain reaction （RT-PCR） was carried out to evaluate phenotypic and biosynthetic activities in the process of differentiation. Meanwhile, Alcian blue staining were used to detect the formation of sulfated glycosaminoglycans （GAGs） in the differentiated cells. Results： The purified ADSCs were fibroblast-like and proliferated rapidly in vitro. The flow cytometry showed that ADSCs were positive for Sca-1 and CD44, negative for CD45 and CD11b. The results of RT-PCR manifested that the gene expressions of Sox-9, aggrecan and collagen Ⅱ, which were chondrocyte specific, were upregulated in medium containing TGF-β1 under hypoxia （2% O2）. Likewise, gene expression of HIF-1 a, which was characteristics of in- tervertebral discs, was also upregulated. Simultaneously, Alcian blue staining exhibited the formation of many GAGs. Conclusions： The approach in our experiment is a simple and effective way to acquire a large quantity of homogenous ADSCs. Rat ADSCs can be differentiated into nucleus pulposus-like cells. ADSCs may replace bone marrow mesenchymal stem cells as a new kind of seed cells in regeneration of degenerated intervertebral discs using cell transolantation therarw.展开更多
After being kept in captivity and isolated from natural predators for more than 1,200 years, P6re David＇s deer has been reintroduced in China and now occurs in a reserve where human activity is the only potential thr...After being kept in captivity and isolated from natural predators for more than 1,200 years, P6re David＇s deer has been reintroduced in China and now occurs in a reserve where human activity is the only potential threat. Antipredator vigilance i~ an important component of survival for many prey animals in their natural habitat. Do deer still adjust vigilance as a function of risk after such a long period of relaxed predation pressure？ Here, we examined vigilance levels in P6re David＇s deer groups as a function of group size, sex and level of human disturbance. The results showed that individual vigilance significantly decreased with group size in all-female groups but not in all-males or mixed-sex groups. In rutting season, males compete with one another and harass females, and we argue that vigilance is partly aimed at threatening males and that such vigilance increases with group size. This explains why overall vigilance did not vary with group size for males in general and for females in mixed-sex groups. Vigilance increased in more disturbed areas but in in male deer only. The results indicate that despite relaxed predation pressure over centuries, P6re David＇s deer can still adjust antipredator responses as a function of perceived risk. Such information may become useful in the rewilding programme now under way for this species in China [Current Zoology 59 （2）： 265-270, 2013].展开更多
Mechanical cues present in the stem cell niche resulting from intracellular processes or external force sources significantly affect the basic functions of stem cells such as self-renewal and differentiation.Creation ...Mechanical cues present in the stem cell niche resulting from intracellular processes or external force sources significantly affect the basic functions of stem cells such as self-renewal and differentiation.Creation of artificial cellular matrices exhibiting intrinsic mechanical cues generated by mechanical movements remains scarce.Herein,we reported on mechanically dynamic hydrogel matrices undergoing photo-induced directional domain sliding movement and their role in regulating embryonic stem cell(ESC)differentiation.The mechanically dynamic hydrogels were prepared via the self-assembly of an alternating hydrophilic and hydrophobic peptide with a photocaged cysteine residue.Upon light irradiation,the assemblies of the caged peptide were converted to non-equilibrated non-caged peptide bilayers that underwent the directional domain sliding motion induced by the thermodynamically favorable hydrophobic collapse transition.Culturing murine ESCs on the mechanically dynamic hydrogels resulted in biased differentiation toward the ectodermal lineage.We further showed that the mechanically dynamic hydrogels stimulated the translocation of a mechanotransduction protein Yes-associated protein(YAP)into the nucleus,implicating a potential mechanotransduction mechanism for the biased differentiation of ESCs.The finding of the biased ectodermal differentiation of ESCs induced by the mechanically dynamic hydrogels implies the great potency of the mechanically dynamic hydrogels as biomaterials for disease therapy and tissue regeneration in the future.展开更多
Diabetes mellitus, characterized by the impaired metabolism of insulin secretion in β cells, is becoming one of the most prevalent diseases around the world. Recently, cell replacement based on differentiation of var...Diabetes mellitus, characterized by the impaired metabolism of insulin secretion in β cells, is becoming one of the most prevalent diseases around the world. Recently, cell replacement based on differentiation of various pluripotent stem cells, including embryonic stern cells, induced pluripo- tent stem cells and multipotent stem cells, such as bone mar- row mesenchymal stem cells, adipose-derived stem cells and gnotobiotic porcine skin-derived stem cells, is becoming a promising therapeutic strategy. Cells derived from pancreatic tissues or other tissues that are relevant to β cell differentiation have also been used as cell source. However, in spite of hopeful experimental results, cell therapy in diabetes still confronts certain obstacles, such as purity of cells, functional differentiation of stem cells and possible tumorigenesis, which, in turn, lead to the seeking of new-generation tools, such as xenogenetic materials. In this review, we will sum- marize the current knowledge and future prospects of cell therapy in diabetes mellitus.展开更多
文摘The effects of ultradry storage on the activity of ATPase and fluidity of plasma membrane in Chinese cabbage (Brassica pekinensis (Lour.) Rupr.) and elm ( Ulmus pumila L.) seeds were investigated. The results indicated that no significant differences in the activity of ATPase and the micro- viscosity of plasma membrane of ultradried (UD) seeds could be found as compared to the control seeds stored under -20 degreesC, although there was a little adverse effect on the seeds with extreme dehydration. The results were consistent with higher vigor level of UD seeds. This implied that ultradry seed storage could protect the integrity of the membrane, maintain its physiological function and improve the storability of seeds. The relationship between sugar and desiccation tolerance of UD seeds was analysed using the HPLC. The results showed that the ratio of reducing to nonreducing sugar was lower in UD seeds than that in control. The content of sucrose and stachyose in elm and Chinese cabbage UD seeds was related to their desiccation tolerance, while no stachyose was detected in corn (Zea mays L.) seeds. This could be one of the reasons for its sensitivity to desiccation.
基金supported by the national“973”tissue engineering project of China(G1999054300)Shanghai Science and Technology Development Foundation(03DJ14021)
文摘Endothelial cells (TEC_3 cells) derived from mouse embryonic stem (ES) cells were used as seed cells to construct blood vessels. Tissue engineered blood vessels were made by seeding 8 × 10~6 smooth muscle cells (SMCs) obtained from rabbit arteries onto a sheet of nonwoven polyglycolic acid (PGA) fibers, which was used as a biodegradable polymer scaffold. After being cultured in DMEM medium for 7 days in vitro, SMCs grew well on the PGA fibers, and the cell-PGA sheet was then wrapped around a silicon tube, and implanted subcutaneously into nude mice. After 6～8 weeks, the silicon tube was replaced with another silicon tube in smaller diameter, and then the TEC_3 cells (endothelial cells differentiated from mouse ES cells) were injected inside the engineered vessel tube as the test group. In the control group only culture medium was injected. Five days later, the engineered vessels were harvested for gross observation, histological and immunohistochemical analysis. The preliminary results demonstrated that the SMC-PGA construct could form a tubular structure in 6～8 weeks and PGA fibers were completely degraded. Histological and immunohistochemical analysis of the newly formed tissue revealed a typical blood vessel structure, including a lining of endothelial cells (ECs) on the lumimal surface and the presence of SMC and collagen in the wall. No EC lining was found in the tubes of control group. Therefore, the ECs differentiated from mouse ES cells can serve as seed cells for endothelium lining in tissue engineered blood vessels.
基金Supported by Medical Guidance Project of Shanghai Science Committee (No. 10411961800)Youth Science Fund of Fudan University (No. 08FQ49)
文摘AIM： To isolate and identify the biological characteristics of human colon cancer stem cells （SW1116 cells） and further study their proteome. METHODS： SW1116 cells were isolated and cultured with a serum-free medium （SFM）. Sphere formation was assayed to observe the formation of colon cancer stem cell spheres. SW1116 cells were inoculated into a serum-containing medium for observing their differentiation characteristics. Proliferation curve and cross-resistance of SWl116 cells to different drugs were detected by MTT. Percentage of SP cells in SW1116 cells was detected with Hoechst33342 staining. Telomerase activity in SW1116cells was checked by polymerase chain reaction （PCR）-enzyme linked immunosorbent assay. Expressions of stem cell relevant genes and proteins were detected by reverse transcription-PCR and Western blot, respectively. Total protein was isolated from SW1116 cells by two-dimensional gel electrophoresis （2-DE） and differentially expressed proteins were identified by tandem mass spectrometry （MALDI-TOF/TOF）. RESULTS： The isolated SW1116 cells presented as spheroid and suspension growths in SFM with a strong self-renewal, proliferation, differentiation and drug-resistance ability. The percentage of SP cells in SW1116 cells was 38.9%. The SW1116 cells co-expressed the CD133 and CD29 proteins. The telomerase activity in SW1116 cells was increased. The expressions of different stem cell relevant genes and proteins were detected. The proteomic analysis showed that the 26 protein spots were differently expressed in SW1116 cells and 10 protein spots were identified as ubiquitin fusion- degradation l-like protein, nuclear chloride channel protein, tubulin 13, Raichu404X, stratifin, F-actin cap- ping protein α-1 subunit, eukaryotic translation elongation factor 1 delta isoform 2, hypothetical protein, glyceraldehyde-3-phosphate dehydrogenase and guanine nucleotide binding protein 13 polypeptide 2-like 1, respectively. CONCLUSION： SW1116 cells are biologically characterized by self-renewal, proliferation and differentiation, and the differently expressed proteins in SW1116 cells may be essential for isolating cancer stem cells.
基金Supported by the New-Century Excellent Talents Plrogram of the Ministry of Education of China the Natural Science Foundation of China under Grant No.10974045
文摘The evidences of three-body and four-body bound states have been reported in a series of very recent experiments with ultracold atoms.Here we study coherent creation of polyatomic molecules via a generalized atom-molecule dark-state technique.By keeping the intermediate trimer or tetramer state essentially unpopulated,the constructive quantum two-channel interference is shown to play an important role in,e.g.coherent atom-pentamer conversion at ultracold temperature.
文摘According to the study on the oil-gas source rocks in China for ten years,in connection with the microscopic, submicroscopic levels, the authors used the microscope photometry together with transmission electronic microscopy, scanning electronic microscopy and proposed a new classification for sedimentary organic matters.
文摘采用自主设计的高压挤压小试装置,将城市混合生活垃圾分为干、湿两种组分。分析其性质表明:在20 MPa和40 MPa挤压压力下,干组分含水率低于30%,热值从2 778 k J/kg分别提升至14 503,11 659 k J/kg。湿组分性质与混合垃圾中的厨余组分相近,易腐成分含量高,可采用厌氧消化处理回收生物质能。采用高压挤压技术作为预处理手段,垃圾能源最大可回收量达5 340 k J/kg,相对直接焚烧提高近90%。高压挤压技术作为预处理手段,可有效提升城市混合生活垃圾的处理效率和能源回收效率。
文摘Objective： To differentiate rat adipose tissue-derived mesenchymal stem cells （ADSCs） into cells with a nucleus pulposus-like phenotype in vitro, so as to lay a foundation for the cell-based transplantation therapy of degenerated intervertebral discs. Methods： Rat ADSCs were isolated only from the subcutaneous inguinal region and purified by limited dilution. ADSCs of the third passages were analyzed by fluorescence activated cell sorter （FACS） to detect the cell surface markers （Sca-1, CD44, CD45, CDI lb）. To induce ADSCs to- wards a nucleus pulposus-like phenotype, ADSCs were immobilized in 3-dimensional alginate hydrogels and cultured in an inducing medium containing transforming growth factor-beta1 （TGF- β1） under hypoxia （2% O2）, while control groups under normoxia （21% O2） in alginate beads in medium with or without the presence of TGF-β 1. Semiquantitative reverse transcription polymerase chain reaction （RT-PCR） was carried out to evaluate phenotypic and biosynthetic activities in the process of differentiation. Meanwhile, Alcian blue staining were used to detect the formation of sulfated glycosaminoglycans （GAGs） in the differentiated cells. Results： The purified ADSCs were fibroblast-like and proliferated rapidly in vitro. The flow cytometry showed that ADSCs were positive for Sca-1 and CD44, negative for CD45 and CD11b. The results of RT-PCR manifested that the gene expressions of Sox-9, aggrecan and collagen Ⅱ, which were chondrocyte specific, were upregulated in medium containing TGF-β1 under hypoxia （2% O2）. Likewise, gene expression of HIF-1 a, which was characteristics of in- tervertebral discs, was also upregulated. Simultaneously, Alcian blue staining exhibited the formation of many GAGs. Conclusions： The approach in our experiment is a simple and effective way to acquire a large quantity of homogenous ADSCs. Rat ADSCs can be differentiated into nucleus pulposus-like cells. ADSCs may replace bone marrow mesenchymal stem cells as a new kind of seed cells in regeneration of degenerated intervertebral discs using cell transolantation therarw.
基金Acknowledgements Financial support for this work was provided by the National Natural Science Foundation of China （No. 31000174 ＆ No. Jl103512）. We thank Prof. Ding Yuhua and other staff members at Dafeng Milu National Natural Reserve for supporting our field research in the reserve. We also thank Xianlong Li, Rongrong Wang, Jia He, Dameng Li, Ruonan Jia, Yilei Hua, and Long Wang for help with the field work, and Chen Ge and Cheng Huang for useful discussions.
文摘After being kept in captivity and isolated from natural predators for more than 1,200 years, P6re David＇s deer has been reintroduced in China and now occurs in a reserve where human activity is the only potential threat. Antipredator vigilance i~ an important component of survival for many prey animals in their natural habitat. Do deer still adjust vigilance as a function of risk after such a long period of relaxed predation pressure？ Here, we examined vigilance levels in P6re David＇s deer groups as a function of group size, sex and level of human disturbance. The results showed that individual vigilance significantly decreased with group size in all-female groups but not in all-males or mixed-sex groups. In rutting season, males compete with one another and harass females, and we argue that vigilance is partly aimed at threatening males and that such vigilance increases with group size. This explains why overall vigilance did not vary with group size for males in general and for females in mixed-sex groups. Vigilance increased in more disturbed areas but in in male deer only. The results indicate that despite relaxed predation pressure over centuries, P6re David＇s deer can still adjust antipredator responses as a function of perceived risk. Such information may become useful in the rewilding programme now under way for this species in China [Current Zoology 59 （2）： 265-270, 2013].
基金supported by the National Key R&D Program of China (2018YFC1313003)the Fundamental Research Funds for the Central Universities+1 种基金the National Natural Science Foundation of China (21774065 and 31622038)the Natural Science Foundation of Tianjin (18JCQNJC14100 and 18JCJQJC48400)
文摘Mechanical cues present in the stem cell niche resulting from intracellular processes or external force sources significantly affect the basic functions of stem cells such as self-renewal and differentiation.Creation of artificial cellular matrices exhibiting intrinsic mechanical cues generated by mechanical movements remains scarce.Herein,we reported on mechanically dynamic hydrogel matrices undergoing photo-induced directional domain sliding movement and their role in regulating embryonic stem cell(ESC)differentiation.The mechanically dynamic hydrogels were prepared via the self-assembly of an alternating hydrophilic and hydrophobic peptide with a photocaged cysteine residue.Upon light irradiation,the assemblies of the caged peptide were converted to non-equilibrated non-caged peptide bilayers that underwent the directional domain sliding motion induced by the thermodynamically favorable hydrophobic collapse transition.Culturing murine ESCs on the mechanically dynamic hydrogels resulted in biased differentiation toward the ectodermal lineage.We further showed that the mechanically dynamic hydrogels stimulated the translocation of a mechanotransduction protein Yes-associated protein(YAP)into the nucleus,implicating a potential mechanotransduction mechanism for the biased differentiation of ESCs.The finding of the biased ectodermal differentiation of ESCs induced by the mechanically dynamic hydrogels implies the great potency of the mechanically dynamic hydrogels as biomaterials for disease therapy and tissue regeneration in the future.
基金supported by the National Basic Research Program of China(2013CB967102)the National Natural Science Foundation of China(31201112)
文摘Diabetes mellitus, characterized by the impaired metabolism of insulin secretion in β cells, is becoming one of the most prevalent diseases around the world. Recently, cell replacement based on differentiation of various pluripotent stem cells, including embryonic stern cells, induced pluripo- tent stem cells and multipotent stem cells, such as bone mar- row mesenchymal stem cells, adipose-derived stem cells and gnotobiotic porcine skin-derived stem cells, is becoming a promising therapeutic strategy. Cells derived from pancreatic tissues or other tissues that are relevant to β cell differentiation have also been used as cell source. However, in spite of hopeful experimental results, cell therapy in diabetes still confronts certain obstacles, such as purity of cells, functional differentiation of stem cells and possible tumorigenesis, which, in turn, lead to the seeking of new-generation tools, such as xenogenetic materials. In this review, we will sum- marize the current knowledge and future prospects of cell therapy in diabetes mellitus.
