Targeted-delivery is of great importance to molecular probes and drugs for cell biology study. Herein we reported 11 sulfur-containing coumarins as cell imaging probes. Different sulfur speciation of the 4 representat...Targeted-delivery is of great importance to molecular probes and drugs for cell biology study. Herein we reported 11 sulfur-containing coumarins as cell imaging probes. Different sulfur speciation of the 4 representative coumarins SC1-SC4 renders them significantly different subcellular localizations and cellular uptake pathways： SC1 containing thioether group located in lysosomes, while sulfoxide and sulfone compounds SC2 and SC3 distributed in the whole cell. Furthermore, the cationic sulfonium containing compound SC4 was internalized by clathrin-mediated endocytosis and localized at mitochondria. By analyzing the molecular parameters of all 11 coumarins, we found that different sulfur speciation affected their lipophilicity and electrostatic surface potential. These two key factors play roles in altering biological behaviors of the coumarins. The results revealed the importance of sulfur speciation on the physicochemical properties and thus subcellular localization of bioprobes. This is useful for designing new functional bioprobes.展开更多
EGF was localized in human fetal, adult and cryptorchid testis and seminoma using an immunohistochemical method. Leydig cells of adult testes stained intensely for EGF while those of fetal testes showed weak staining ...EGF was localized in human fetal, adult and cryptorchid testis and seminoma using an immunohistochemical method. Leydig cells of adult testes stained intensely for EGF while those of fetal testes showed weak staining reaction. In addition, some spermatogonia and occasional peritubular myoid cells of adult testis stained positively. In cryptorchid testis, there were clusters of Leydig cells interspersed between seminiferous tubules with varying staining intensities. The number of positively stained cells in the cryptorchid testis were fewer than that in adult testes. The decrease in the number of Leydig cells producing EGF may account for the spermatogenesis arrest and infertility associated with this disorder.Intense staining of the cytoplasm of seminoma cells was observed, suggesting that the high production of EGF may be related to their invasive property. In conclusion, EGF is produced by human testis and Leydig cells are the principal source of this cytokine.展开更多
Ⅰ. INTRODUCTIONIn[1], Kac raised a problem as how to characterize the "general" Lie algebra gl（V）<sub>fin</sub>. The aim of this note is to solve the problem. And we give the structure of the ...Ⅰ. INTRODUCTIONIn[1], Kac raised a problem as how to characterize the "general" Lie algebra gl（V）<sub>fin</sub>. The aim of this note is to solve the problem. And we give the structure of the group associated to g/（V）<sub>fin</sub>.展开更多
Enzyme immobilization is a crucial step in advancing the industrial application of biocatalysts.Achieving effective enzyme encapsulation and precise tailoring of the enzyme microenvironment is essential for maximizing...Enzyme immobilization is a crucial step in advancing the industrial application of biocatalysts.Achieving effective enzyme encapsulation and precise tailoring of the enzyme microenvironment is essential for maximizing catalytic performance,yet remains a challenge.In this study,we synthesized hierarchically porous covalent organic framework(COF)aerogels,incorporating alkyl chains of varying lengths on the framework,to enable efficient enzyme immobilization,facilitate mass transfer and fine-tune the microenvironment.The introduction of alkyl chains modulated enzyme-COF interactions,inducing interfacial activation and promoting open enzyme conformation with more accessible active sites.Notably,increasing the length of alkyl chains strengthened enzyme-COF interactions,and the enzyme immobilized on the COF aerogel with the longest alkyl chains(C6)showed the highest activity and stability,achieving more than twice the conversion of the free enzyme even at low temperatures(0–20°C)and maintaining 90%of its initial conversion after thermal treatment at 80°C.Furthermore,COF aerogel-immobilized enzymes maintained high conversion in continuous-flow reactions for 8 h,demonstrating operational robustness.The generality of this approach is validated with multiple lipases,showing enhanced activity.This study highlights the potential of functionalized COF aerogels as a versatile and robust platform for developing high-performance biocatalysts.展开更多
基金financial support from the National Key Basic Research Support Foundation of China(No. 2015CB856301)the National Natural Scientific Foundation of China (Nos. 21571007, 21271013,21321001)
文摘Targeted-delivery is of great importance to molecular probes and drugs for cell biology study. Herein we reported 11 sulfur-containing coumarins as cell imaging probes. Different sulfur speciation of the 4 representative coumarins SC1-SC4 renders them significantly different subcellular localizations and cellular uptake pathways： SC1 containing thioether group located in lysosomes, while sulfoxide and sulfone compounds SC2 and SC3 distributed in the whole cell. Furthermore, the cationic sulfonium containing compound SC4 was internalized by clathrin-mediated endocytosis and localized at mitochondria. By analyzing the molecular parameters of all 11 coumarins, we found that different sulfur speciation affected their lipophilicity and electrostatic surface potential. These two key factors play roles in altering biological behaviors of the coumarins. The results revealed the importance of sulfur speciation on the physicochemical properties and thus subcellular localization of bioprobes. This is useful for designing new functional bioprobes.
文摘EGF was localized in human fetal, adult and cryptorchid testis and seminoma using an immunohistochemical method. Leydig cells of adult testes stained intensely for EGF while those of fetal testes showed weak staining reaction. In addition, some spermatogonia and occasional peritubular myoid cells of adult testis stained positively. In cryptorchid testis, there were clusters of Leydig cells interspersed between seminiferous tubules with varying staining intensities. The number of positively stained cells in the cryptorchid testis were fewer than that in adult testes. The decrease in the number of Leydig cells producing EGF may account for the spermatogenesis arrest and infertility associated with this disorder.Intense staining of the cytoplasm of seminoma cells was observed, suggesting that the high production of EGF may be related to their invasive property. In conclusion, EGF is produced by human testis and Leydig cells are the principal source of this cytokine.
基金Project supported partly by the National Natural Science Foundation of China.
文摘Ⅰ. INTRODUCTIONIn[1], Kac raised a problem as how to characterize the "general" Lie algebra gl（V）<sub>fin</sub>. The aim of this note is to solve the problem. And we give the structure of the group associated to g/（V）<sub>fin</sub>.
基金the National Natural Science Foundation of China(grant no.22271015)TaiShan Scholars Program(no.tsqn202408322)Beijing Institute of Technology Research Fund Program,and Young Elite Scientists Sponsorship Program by BAST(no.BYESS2024365)for financial support,and Analysis and Testing Center of Beijing Institute of Technology.
文摘Enzyme immobilization is a crucial step in advancing the industrial application of biocatalysts.Achieving effective enzyme encapsulation and precise tailoring of the enzyme microenvironment is essential for maximizing catalytic performance,yet remains a challenge.In this study,we synthesized hierarchically porous covalent organic framework(COF)aerogels,incorporating alkyl chains of varying lengths on the framework,to enable efficient enzyme immobilization,facilitate mass transfer and fine-tune the microenvironment.The introduction of alkyl chains modulated enzyme-COF interactions,inducing interfacial activation and promoting open enzyme conformation with more accessible active sites.Notably,increasing the length of alkyl chains strengthened enzyme-COF interactions,and the enzyme immobilized on the COF aerogel with the longest alkyl chains(C6)showed the highest activity and stability,achieving more than twice the conversion of the free enzyme even at low temperatures(0–20°C)and maintaining 90%of its initial conversion after thermal treatment at 80°C.Furthermore,COF aerogel-immobilized enzymes maintained high conversion in continuous-flow reactions for 8 h,demonstrating operational robustness.The generality of this approach is validated with multiple lipases,showing enhanced activity.This study highlights the potential of functionalized COF aerogels as a versatile and robust platform for developing high-performance biocatalysts.
