根据康奈尔净碳水化合物和蛋白质体系(Cornell Net Carbohydrate and Protein System,CNCPS)提出的蛋白质分类方法,就不同青贮处理对红薯(Ipomoea batatas)藤、狼尾草(Pennisetum alopecuroides)和象草(Pennisetum purpureum)粗蛋白质、非蛋白氮、可溶蛋白、酸性洗涤不溶蛋白和中性洗涤不溶粗蛋白含量的影响进行了分析,并根据CNCPS提出的计算方法对粗蛋白质中非蛋白氮(PA)、快速降解蛋白质(PB1)、结合蛋白质(PC)、中度降解蛋白质(PB2)和慢速降解蛋白质(PB3)组分的含量进行了计算.结果表明,无论是常规青贮还是低水分青贮,蛋白质组分的总体变化规律基本一致,均表现为PA含量提高,而PB1含量下降.青贮红薯藤PA和PC含量均显著高于原料,而PB1含量则显著低于原料(P<0.05),PB2,PB3含量无显著变化(P>0.05),不同青贮处理对红薯藤蛋白质组分无显著影响(P>0.05).青贮狼尾草PA含量显著高于原料,PB2含量显著低于原料,PC含量则只有低水分青贮显著高于原料(P<0.05).低水分青贮狼尾草PB2含量显著低于常规青贮,而PC含量则显著高于常规青贮(P<0.05).青贮象草的PA含量显著高于原料(P<0.05),PB1含量只在低水分青贮时显著增高(P<0.05).常规青贮和低水分青贮象草之间各蛋白质组分均无显著差异(P>0.05).
Abstract Objective To examine UVB-induced responses in normal human keratinocytes （HaCaT） and epidermoid carcinoma cells （A431） at the cellular and molecular level, and investigated the protective effect of salidroside. Methods Cells irradiated by UVB at various dosage and their viability was assessed by MTT assays, cell cycle was analysed by flow cytometry. The expression of NF-KB, BCL-2, and CDK6 after 50 J/㎡ UVB irradiation were detected by RT-PCR and western blotting. Results Our results confirmed greater tolerance of A341 cells to UVB-induced damage such as cell viability and cell cycle arrest, which was accompanied by differential expression changes in NF-KB, BCL-2, and CDK6. UVB exposure resulted in HaCaT cells undergoing G1-S phase arrest. When treated with salidroside, HaCaT survival was significantly enhanced following exposure to UVB, suggesting great therapeutic potential for this compound. Conclusion Taken together, our study suggests that A431 respond differently to UVB than norma HaCaT cells, and supports a role for NF-KB, CDK6, and BCL-2 in UVB-induced cell G1-S phase arrest Furthermore, salidroside can effectively protect HaCaT from UVB irradiation.
ZHOU Mei JuanZHENG LiGUO LingLIU Wei LingLV ChaoJIANG Li HongOU Cheng ShanDING Zhen Hua
