By means of improved ligand-field theory, the ＂pure electronic＂ pressure-induced shifts （PS＇s） and the PS＇s due to electron-phonon interaction （EPI） of R1 line and R2 line of YAG：Cr^3＋ have been calculated, ...By means of improved ligand-field theory, the ＂pure electronic＂ pressure-induced shifts （PS＇s） and the PS＇s due to electron-phonon interaction （EPI） of R1 line and R2 line of YAG：Cr^3＋ have been calculated, respectively. The calculated results are in very good agreement with the experimental data. It is demonstrated that the admixture of │t^2 2（^3T1）e^4T2〉 and │t^3 2 ^2E〉 bases in the wavefunction of RI level of YAG：Crs＋ and its change with pressure play a key role for the PS of RI line. The behaviors of the ＂pure electronic＂ PS of RI line and the PS of RI line due to EPI are different. It is the combined eEect of them that gives rise to the total PS of R1 line, which has satisfactorily explained the experimental results. The systematic analyses and comparisons between the feature of R1-line PS of YAG：Cr^3＋ and the ones of three laser crystals （GSGG：Cr^3＋, GGG：Cr^3＋ and ruby） have been made, and the origin of the difference between them has been revealed.展开更多
As a key factor leading to the pressure-dependent R1-line-shift reversal and R1-state lifetime, at 10 K, the pressure-dependent variation of mixing-degree of ｜t2^2（^3T1）e^4T2） and ｜t2^32E〉 base-wavefunetions in ...As a key factor leading to the pressure-dependent R1-line-shift reversal and R1-state lifetime, at 10 K, the pressure-dependent variation of mixing-degree of ｜t2^2（^3T1）e^4T2） and ｜t2^32E〉 base-wavefunetions in the wavefunction of R1 state of LLGG：Cr^3＋ has been calculated and analyzed. From this, the physical origin of the pressure-dependent R1-line-shift reversal has been revealed. Furthermore, by using the pressure-dependent values of the sum of all square mixlng-coefficients of ｜t2^2 （^3T1）e^4T2〉 in the wavefunction of R1 state, the lifetimes of R1 state of LLG G：Cr^3＋ at various pressures have been calculat, ed, which arc in good agreement with observed results. The quantum anticrossing effect between t2^32E and t2^2 （^3T1）e^4T2 levels due to both spin-orbital interaction and electron-phonon interaction is remarkable, which is related to the admixture of ｜t2^2（^3T1）e^4T2） and ｜t2^32E〉 as well as the low high crystal-field transition.展开更多
Twelve steroids, including eight ergostane-type sterols and four mono-glucosides of ergostane-type sterols, were isolated from the ethyl acetate soluble fraction of the fungus Pleurotus ostreatus ( Jacq. : Fr.) Kummer...Twelve steroids, including eight ergostane-type sterols and four mono-glucosides of ergostane-type sterols, were isolated from the ethyl acetate soluble fraction of the fungus Pleurotus ostreatus ( Jacq. : Fr.) Kummer. A new compound 3-O-beta-D-glucopyranosyl-22E, 24R-ergosta-7, 22-diene-5alpha, 6beta, 9alpha-triol, was structurally elucidated by spectroscopic and chemical methods. The eleven known compounds were 22E, 24R-ergosta-7, 22-diene-3beta, 5alpha, 6beta, 9alpha-tetraol; 3-O-beta-D-glucopyranosyl-22E, 24R-ergosta-7, 22-diene-5alpha, 6beta-diol; 22E, 24R-ergosta-7, 22-diene-3beta, 5alpha, 6beta-triol; 22E, 24R-ergosta-5, 7, 22-trien-3beta-ol 3-O-beta-D-glucopyranoside; ergosterol; 22E, 24R-ergosta-7, 22-dien-3beta-ol 3-O-beta-D-glucopyranoside; 22E, 24R-ergosta-7, 22-diene-3beta-ol; 22E, 24R-ergosta-4, 6, 8, 22-tetraen-3-one; 22E, 24R-ergosta-7, 22-diene-3beta, 5alpha, 6alpha-triol; ergosterol peroxide; 22E, 24R-ergosta-7, 22-diene-3beta, 5alpha-diol-6-one.展开更多
A new sterol, ergosta-8(9),22-diene-3,5,6,7-tetraol(3β,5α,6β,7α,22E)(A) together with three known sterols: 3β, 5α,6β-trihydroxyergosta-7,22-diene (B), 3β-hydroxy-5α,8α- epidioxyer-gosta-6,22-diene (C) and er...A new sterol, ergosta-8(9),22-diene-3,5,6,7-tetraol(3β,5α,6β,7α,22E)(A) together with three known sterols: 3β, 5α,6β-trihydroxyergosta-7,22-diene (B), 3β-hydroxy-5α,8α- epidioxyer-gosta-6,22-diene (C) and ergosterol (D) were isolated from the mycelia of an unidentified endophytic fungus separated from Castaniopsis fissa (chestnut tree). Compound A exhibited potent selective cytotoxicity against Bel-7402, NCI4460 and L-02 cell lines with IC50 values 8.445, 5.03, 13.621 μg/mL, respectively.展开更多
Aim： To investigate the activity of RRR-α-tocopheryloxybutyric acid （TOB）, an ether analog of RRR-α-tocopheryl succinate （VES）, in prostate cancer cells. Methods： VES and TOB were used to treat prostate cancer...Aim： To investigate the activity of RRR-α-tocopheryloxybutyric acid （TOB）, an ether analog of RRR-α-tocopheryl succinate （VES）, in prostate cancer cells. Methods： VES and TOB were used to treat prostate cancer LNCaP, PC3, and 22Rvl cells and primary-cultured prostate fibroblasts. The proliferation rates were determined by MTT assay, the cell viabilities were determined by trypan blue exclusion assay, and the cell deaths were evaluated by using Cell Death Detection ELISA kit. The protein expression levels were determined by Western blot analysis. Results： The MTT growth assay demonstrated that TOB could effectively suppress the proliferation of prostate cancer cells, but not normal prostate fibroblasts. Mechanism dissections revealed that TOB reduced cell viability and induced apoptosis in prostate cancer cells similar to VES. In addition, both TOB and VES suppressed prostate-specific antigen （PSA） at the transcriptional level leading to reduced PSA protein expression. Furthermore, vitamin D receptor （VDR） expression increased after the addition of TOB. Conclusion： Our data suggests that the VES derivative, TOB, is effective in inhibiting prostate cancer cell proliferation, suggesting that TOB could be used for both chemopreventive and chemotherapeutic purposes in the future.展开更多
The mechanism regulating proteasomal activity under proteotoxic stress conditions remains unclear.Here,we showed that arsenite-induced proteotoxic stress resulted in upregulation of Arabidopsis homologous PUB22 and PU...The mechanism regulating proteasomal activity under proteotoxic stress conditions remains unclear.Here,we showed that arsenite-induced proteotoxic stress resulted in upregulation of Arabidopsis homologous PUB22 and PUB23 U-boxE3 ubiquitin ligases and that pub22 pub23 double mutants displayed arsenite-insensitive seed germination and root growth phenotypes.PUB22/PUB23 downregulated 26 S proteasome activity by promoting the dissociation of the 19 S regulatory particle from the holo-proteasome complex,resulting in intracellular accumulation of UbG76 VGFP,an artificial substrate of the proteasome complex,and insoluble poly-ubiquitinated proteins.These results suggest that PUB22/PUB23 play a critical role in arsenite-induced proteotoxic stress response via negative regulation of 26 S proteasome integrity.展开更多
The blood-brain barrier permeability of 20（S） and 20（R）-protopanaxatriol epimers and dammar-20（22）E,24-diene- 313,6α,12β-triol were investigated using the MDCK-pHaMDR cell monolayer model. The bidirectional pe...The blood-brain barrier permeability of 20（S） and 20（R）-protopanaxatriol epimers and dammar-20（22）E,24-diene- 313,6α,12β-triol were investigated using the MDCK-pHaMDR cell monolayer model. The bidirectional permeability tests were carried out, and the apparent permeability coefficients （Papp） were calculated. The two protopanaxatriol epimers showed good permeability with Papp values of-10^-5 cm/s, whereas dammar-20（22）E,24-diene-3β,6α, 12β-triol showed poor permeability with Papp of 〈1 × 10^-7 cm/s. The three compounds showed differences in intracellular accumulations due to their different structures. Inhibition of P-gp with verapamil showed that the transport mechanisms in MDCK-pHaMDR cell monolayer for compounds 1 and 2 epimers were not only simple passive diffusion but also involving an effiux way mediated by P-gp. These findings provided new basis for the further study of compounds 1 and 2 acting on the brain.展开更多
文摘By means of improved ligand-field theory, the ＂pure electronic＂ pressure-induced shifts （PS＇s） and the PS＇s due to electron-phonon interaction （EPI） of R1 line and R2 line of YAG：Cr^3＋ have been calculated, respectively. The calculated results are in very good agreement with the experimental data. It is demonstrated that the admixture of │t^2 2（^3T1）e^4T2〉 and │t^3 2 ^2E〉 bases in the wavefunction of RI level of YAG：Crs＋ and its change with pressure play a key role for the PS of RI line. The behaviors of the ＂pure electronic＂ PS of RI line and the PS of RI line due to EPI are different. It is the combined eEect of them that gives rise to the total PS of R1 line, which has satisfactorily explained the experimental results. The systematic analyses and comparisons between the feature of R1-line PS of YAG：Cr^3＋ and the ones of three laser crystals （GSGG：Cr^3＋, GGG：Cr^3＋ and ruby） have been made, and the origin of the difference between them has been revealed.
文摘As a key factor leading to the pressure-dependent R1-line-shift reversal and R1-state lifetime, at 10 K, the pressure-dependent variation of mixing-degree of ｜t2^2（^3T1）e^4T2） and ｜t2^32E〉 base-wavefunetions in the wavefunction of R1 state of LLGG：Cr^3＋ has been calculated and analyzed. From this, the physical origin of the pressure-dependent R1-line-shift reversal has been revealed. Furthermore, by using the pressure-dependent values of the sum of all square mixlng-coefficients of ｜t2^2 （^3T1）e^4T2〉 in the wavefunction of R1 state, the lifetimes of R1 state of LLG G：Cr^3＋ at various pressures have been calculat, ed, which arc in good agreement with observed results. The quantum anticrossing effect between t2^32E and t2^2 （^3T1）e^4T2 levels due to both spin-orbital interaction and electron-phonon interaction is remarkable, which is related to the admixture of ｜t2^2（^3T1）e^4T2） and ｜t2^32E〉 as well as the low high crystal-field transition.
文摘A new sterol, ergosta-8(9),22-diene-3,5,6,7-tetraol(3β,5α,6β,7α,22E)(A) together with three known sterols: 3β, 5α,6β-trihydroxyergosta-7,22-diene (B), 3β-hydroxy-5α,8α- epidioxyer-gosta-6,22-diene (C) and ergosterol (D) were isolated from the mycelia of an unidentified endophytic fungus separated from Castaniopsis fissa (chestnut tree). Compound A exhibited potent selective cytotoxicity against Bel-7402, NCI4460 and L-02 cell lines with IC50 values 8.445, 5.03, 13.621 μg/mL, respectively.
文摘Aim： To investigate the activity of RRR-α-tocopheryloxybutyric acid （TOB）, an ether analog of RRR-α-tocopheryl succinate （VES）, in prostate cancer cells. Methods： VES and TOB were used to treat prostate cancer LNCaP, PC3, and 22Rvl cells and primary-cultured prostate fibroblasts. The proliferation rates were determined by MTT assay, the cell viabilities were determined by trypan blue exclusion assay, and the cell deaths were evaluated by using Cell Death Detection ELISA kit. The protein expression levels were determined by Western blot analysis. Results： The MTT growth assay demonstrated that TOB could effectively suppress the proliferation of prostate cancer cells, but not normal prostate fibroblasts. Mechanism dissections revealed that TOB reduced cell viability and induced apoptosis in prostate cancer cells similar to VES. In addition, both TOB and VES suppressed prostate-specific antigen （PSA） at the transcriptional level leading to reduced PSA protein expression. Furthermore, vitamin D receptor （VDR） expression increased after the addition of TOB. Conclusion： Our data suggests that the VES derivative, TOB, is effective in inhibiting prostate cancer cell proliferation, suggesting that TOB could be used for both chemopreventive and chemotherapeutic purposes in the future.
基金supported by grants from the National Research Foundation(Mid-Career Researcher Program Project No.2017R1A2B2006750 and Basic Science Research Program Project No.2018R1A6A1A03025607),Republic of Korea,to Woo T.Kim。
文摘The mechanism regulating proteasomal activity under proteotoxic stress conditions remains unclear.Here,we showed that arsenite-induced proteotoxic stress resulted in upregulation of Arabidopsis homologous PUB22 and PUB23 U-boxE3 ubiquitin ligases and that pub22 pub23 double mutants displayed arsenite-insensitive seed germination and root growth phenotypes.PUB22/PUB23 downregulated 26 S proteasome activity by promoting the dissociation of the 19 S regulatory particle from the holo-proteasome complex,resulting in intracellular accumulation of UbG76 VGFP,an artificial substrate of the proteasome complex,and insoluble poly-ubiquitinated proteins.These results suggest that PUB22/PUB23 play a critical role in arsenite-induced proteotoxic stress response via negative regulation of 26 S proteasome integrity.
基金The National New Drug R&D Program(Grant No.2011BAI07B082009ZX09301-010)of China
文摘The blood-brain barrier permeability of 20（S） and 20（R）-protopanaxatriol epimers and dammar-20（22）E,24-diene- 313,6α,12β-triol were investigated using the MDCK-pHaMDR cell monolayer model. The bidirectional permeability tests were carried out, and the apparent permeability coefficients （Papp） were calculated. The two protopanaxatriol epimers showed good permeability with Papp values of-10^-5 cm/s, whereas dammar-20（22）E,24-diene-3β,6α, 12β-triol showed poor permeability with Papp of 〈1 × 10^-7 cm/s. The three compounds showed differences in intracellular accumulations due to their different structures. Inhibition of P-gp with verapamil showed that the transport mechanisms in MDCK-pHaMDR cell monolayer for compounds 1 and 2 epimers were not only simple passive diffusion but also involving an effiux way mediated by P-gp. These findings provided new basis for the further study of compounds 1 and 2 acting on the brain.
