Heavy metals, including cadmium (Cd), are widespread pollutants of great environmental concern because of their ac- cumulation and toxicity. Environmental conditions can affect the accumulation and elimination of Cd i...Heavy metals, including cadmium (Cd), are widespread pollutants of great environmental concern because of their ac- cumulation and toxicity. Environmental conditions can affect the accumulation and elimination of Cd in organisms. The aim of this study is to understand the respective responses of metallothioneins (MTs), P-glycoprotein (P-gp), and heat shock protein 70 (hsp70) genes in the mantle and digestive gland of the oyster Crassostrea gigas exposed to 10 g L 1 Cd for 28 days, followed by a depura- tion period of 35 days under different feeding strategies. The MT expression in the digestive gland was higher than in mantle, and was induced in a fluctuating pattern throughout the time of the whole experiment when the oyster was exposed to Cd. The results indicated an enhanced MT activity is required for Cd detoxification. Expression levels of P-gp in the mantle of Cd-exposed oysters fed with algae increased in the first two weeks of the accumulation phase. Then the induction weakened, but the expression still in- creased significantly compared with the control group fed without algae. The P-gp levels in the digestive gland were under-regulated during both the contamination and decontamination periods except in the group fed with Dicrateria inornata at day 0.083. The in- duction of P-gp is possibly related to the important role of pumping Cd out of the cell, while a major implication of P-gp expression inhibition would be a disruption of the protein synthesis. Hsp70 expression exhibited an overall decreasing trend. The highest relative hsp70 inhibition occurred during day 42 to day 63, with approximately 4-fold and 10-fold lower hsp70 levels as compared to the C.gigas feeding with no algae in the mantle and digestive gland, respectively. The induction of hsp70 may be explained by the re- folding of protein in presence of Cd, followed by the inhibition of hsp70 when the protein synthesis was disrupted.展开更多
In search of new systems with a photoexcited redox pair which exhibits a strong and stable photoinduced absorption band to understand the photophyscial and photochemical properties of electron transfer between fullere...In search of new systems with a photoexcited redox pair which exhibits a strong and stable photoinduced absorption band to understand the photophyscial and photochemical properties of electron transfer between fullerenes (C 60/C 70) and organic donor [N,N,N′,N′-tetra(p-methylphenyl)-4,4′-diamino-1,1′-diphenyl sulphide (TPDAS)], we studied characteristic absorption spectra in the near-IR region obtained from 532 nm nanosecond laser flash photolysis of a mixture of the fullerenes (C 60/C 70) and TPDAS in polar solvents. When fullerenes (C 60/C 70) were photoexcited, the rise of the radical anion of fullerenes (C 60/C 70) with the rapid decay of their excited triplet states were observed in benzonitrile. It can be deduced that the electron transfer reaction does take place from TPDAS to excited triplet state of fullerenes (C 60/C 70). The rate constants (k et) and quantum yields (Φ et) of this process have been also evaluated.展开更多
基金supported by grants from The National Natural Science Foundation of China(81172365)The Research Foundation of Health Bureau of Hunan Province(2007B112)~~
文摘探讨姜黄素对耐热肝癌细胞(HepG2/TT)阿霉素耐受性的逆转作用及其机制.用MTT检测细胞活力,PI染色流式细胞术检测细胞凋亡,高效液相色谱法检测细胞内阿霉素的积累,Western blot检测细胞P-糖蛋白(P-glycoprotein,P-gp)、热休克蛋白70(heat shock protein 70,Hsp70)和caspase-3的表达.耐热肝癌细胞HepG2/TT能耐受阿霉素引起的细胞毒性和凋亡;姜黄素在5、10和20μmol/L时,能浓度依赖性地降低阿霉素对HepG2/TT细胞的IC50,增强阿霉素对HepG2/TT细胞的凋亡诱导作用.耐热肝癌细胞HepG2/TT与非耐热肝癌细胞HepG2比较,其P-gp和Hsp70的表达水平明显增高;10μmol/L姜黄素处理24 h后,HepG2/TT细胞P-gp和Hsp70的表达水平显著下降.HepG2/TT细胞内阿霉素的积累低于HepG2细胞;10μmol/L姜黄素处理3 h后,HepG2/TT细胞内阿霉素的积累明显增加.HepG2/TT细胞能抑制阿霉素激活caspase-3;10μmol/L姜黄素处理24 h后,阿霉素对HepG2/TT细胞caspase-3的激活作用增强.上述结果表明,姜黄素能逆转耐热肝癌细胞HepG2/TT的阿霉素耐受性,其机制可能与其下调P-gp和Hsp70的表达,进而促进阿霉素激活caspase-3有关.
基金supported by the Earmarked Fund for Modern Agro-industry Technology Research System in Shandong Province (No. SDAIT-14)the major Agricultural Applied Technological Innovation Program in Shandong Province: Construction and Demonstration of Ecological Farming Model of Monomeric Triploid Oyster
文摘Heavy metals, including cadmium (Cd), are widespread pollutants of great environmental concern because of their ac- cumulation and toxicity. Environmental conditions can affect the accumulation and elimination of Cd in organisms. The aim of this study is to understand the respective responses of metallothioneins (MTs), P-glycoprotein (P-gp), and heat shock protein 70 (hsp70) genes in the mantle and digestive gland of the oyster Crassostrea gigas exposed to 10 g L 1 Cd for 28 days, followed by a depura- tion period of 35 days under different feeding strategies. The MT expression in the digestive gland was higher than in mantle, and was induced in a fluctuating pattern throughout the time of the whole experiment when the oyster was exposed to Cd. The results indicated an enhanced MT activity is required for Cd detoxification. Expression levels of P-gp in the mantle of Cd-exposed oysters fed with algae increased in the first two weeks of the accumulation phase. Then the induction weakened, but the expression still in- creased significantly compared with the control group fed without algae. The P-gp levels in the digestive gland were under-regulated during both the contamination and decontamination periods except in the group fed with Dicrateria inornata at day 0.083. The in- duction of P-gp is possibly related to the important role of pumping Cd out of the cell, while a major implication of P-gp expression inhibition would be a disruption of the protein synthesis. Hsp70 expression exhibited an overall decreasing trend. The highest relative hsp70 inhibition occurred during day 42 to day 63, with approximately 4-fold and 10-fold lower hsp70 levels as compared to the C.gigas feeding with no algae in the mantle and digestive gland, respectively. The induction of hsp70 may be explained by the re- folding of protein in presence of Cd, followed by the inhibition of hsp70 when the protein synthesis was disrupted.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (No .2 0 0 710 12 ) ,ResearchFundfortheYoungTeacherPro gramofHigherEducationofChina (No .2 0 0 0 6 5 )andtheNaturalScienceFoundationofGuangdongProvince (No .0 0 0 70 0 )
文摘In search of new systems with a photoexcited redox pair which exhibits a strong and stable photoinduced absorption band to understand the photophyscial and photochemical properties of electron transfer between fullerenes (C 60/C 70) and organic donor [N,N,N′,N′-tetra(p-methylphenyl)-4,4′-diamino-1,1′-diphenyl sulphide (TPDAS)], we studied characteristic absorption spectra in the near-IR region obtained from 532 nm nanosecond laser flash photolysis of a mixture of the fullerenes (C 60/C 70) and TPDAS in polar solvents. When fullerenes (C 60/C 70) were photoexcited, the rise of the radical anion of fullerenes (C 60/C 70) with the rapid decay of their excited triplet states were observed in benzonitrile. It can be deduced that the electron transfer reaction does take place from TPDAS to excited triplet state of fullerenes (C 60/C 70). The rate constants (k et) and quantum yields (Φ et) of this process have been also evaluated.
