In plant cells the plasma membrane is a highly elaborated structure that functions as the point of exchange with adjoining cells, cell walls and the external environment. In this study, we investigated the structure a...In plant cells the plasma membrane is a highly elaborated structure that functions as the point of exchange with adjoining cells, cell walls and the external environment. In this study, we investigated the structure and function characteristic of wheat root plasma membrane (PM) as affected by H2O2 and Fe by using fluorescence spectroscopic and attenuated total reflectance infrared (ATR-IR) techniques. The results showed that these oxidant damaged induced an obviously reduced membrane fluidity were observed in the roots PM treated with the 200 μM H2O2, FeSO4, and FeCl3. Computer-aided software analyses of the FTIR spectrum indicated that the content of the α-helices decreased and β-sheet increased in the secondary structures of proteins after exposure to the oxidants of 200 μM H2O2, FeSO4, and FeCl3. The number of P=O and C=C bonds area declined rapidly in the lipids of the membrane under the oxidants stress. These structural alterations might explain the reason of the roots PM instability under most of the abiotic stress.展开更多
目的探讨薄荷醇对皮肤角质层结构影响的作用机制。方法大鼠皮肤角质层样本和健康志愿者皮肤给予薄荷醇后,测定全衰减反射傅里叶变换红外光谱(ATR-FTIR)在皮肤角质层的变化,以确定皮肤角质层结构是否改变。结果在大鼠皮肤实验中,与对照...目的探讨薄荷醇对皮肤角质层结构影响的作用机制。方法大鼠皮肤角质层样本和健康志愿者皮肤给予薄荷醇后,测定全衰减反射傅里叶变换红外光谱(ATR-FTIR)在皮肤角质层的变化,以确定皮肤角质层结构是否改变。结果在大鼠皮肤实验中,与对照组和溶剂组相比,氮酮组大鼠角质层中的CH2对称振动(2 854 cm 1)发生了相对位移,角蛋白NH-C=O振动I峰(1 659 cm 1)及II峰(1 637 cm 1)发生了位移,NH-C=O振动I峰发生了裂峰;薄荷醇组大鼠角质层中CH2非对称振动(2 925 cm 1)、CH2对称振动(2 854 cm 1)发生相对位移。在人体皮肤试验中,与对照区和溶剂区相比,氮酮组CH2非对称振动(2 921.5 cm 1)和CH2对称振动(2 852.1 cm 1)发生了3～4个波长位移;薄荷醇组CH2非对称振动(2 922.7 cm 1)和CH2对称振动(2 853.8 cm 1)发生了3～4个波长位移。结论薄荷醇可能是通过改变角质层中脂质的构象,使角质层脂质双分子层的流动性增加、有序致密结构改变,降低皮肤屏障作用,从而使药物的透过性增加。展开更多
应用太赫兹时域光谱技术结合移动窗口相关系数法筛选与种子老化密切相关的太赫兹特征波段。选取3个不同品种的玉米种子,并制备人工老化0、1、2、3、4 d的实验样本,采用衰减全反射(Attenuated total reflection,ATR)附件采集从样本分离...应用太赫兹时域光谱技术结合移动窗口相关系数法筛选与种子老化密切相关的太赫兹特征波段。选取3个不同品种的玉米种子,并制备人工老化0、1、2、3、4 d的实验样本,采用衰减全反射(Attenuated total reflection,ATR)附件采集从样本分离得到的种胚和胚乳粉末的太赫兹吸光度谱(0.2~80 cm^-1),应用移动窗口相关系数法(窗口宽度为10,阈值为0.3)筛选样本种胚和胚乳特征谱区。结果表明,不同品种样本筛选得到的老化特征谱区差异显著,说明种子老化进程受品种影响较大;在相同的老化阶段,不同品种样本的特征谱区也存在部分共同区间,且主要集中在60~80 cm^-1,说明老化进程中有些成分的变化相近;种胚和胚乳在相同老化阶段筛选的特征谱区不同,说明两者在老化进程中生理变化存在差异。本研究表明太赫兹时域光谱结合化学计量学方法可用于快速表征并探测玉米种子老化的动态变化过程。展开更多
文摘In plant cells the plasma membrane is a highly elaborated structure that functions as the point of exchange with adjoining cells, cell walls and the external environment. In this study, we investigated the structure and function characteristic of wheat root plasma membrane (PM) as affected by H2O2 and Fe by using fluorescence spectroscopic and attenuated total reflectance infrared (ATR-IR) techniques. The results showed that these oxidant damaged induced an obviously reduced membrane fluidity were observed in the roots PM treated with the 200 μM H2O2, FeSO4, and FeCl3. Computer-aided software analyses of the FTIR spectrum indicated that the content of the α-helices decreased and β-sheet increased in the secondary structures of proteins after exposure to the oxidants of 200 μM H2O2, FeSO4, and FeCl3. The number of P=O and C=C bonds area declined rapidly in the lipids of the membrane under the oxidants stress. These structural alterations might explain the reason of the roots PM instability under most of the abiotic stress.
文摘目的探讨薄荷醇对皮肤角质层结构影响的作用机制。方法大鼠皮肤角质层样本和健康志愿者皮肤给予薄荷醇后,测定全衰减反射傅里叶变换红外光谱(ATR-FTIR)在皮肤角质层的变化,以确定皮肤角质层结构是否改变。结果在大鼠皮肤实验中,与对照组和溶剂组相比,氮酮组大鼠角质层中的CH2对称振动(2 854 cm 1)发生了相对位移,角蛋白NH-C=O振动I峰(1 659 cm 1)及II峰(1 637 cm 1)发生了位移,NH-C=O振动I峰发生了裂峰;薄荷醇组大鼠角质层中CH2非对称振动(2 925 cm 1)、CH2对称振动(2 854 cm 1)发生相对位移。在人体皮肤试验中,与对照区和溶剂区相比,氮酮组CH2非对称振动(2 921.5 cm 1)和CH2对称振动(2 852.1 cm 1)发生了3～4个波长位移;薄荷醇组CH2非对称振动(2 922.7 cm 1)和CH2对称振动(2 853.8 cm 1)发生了3～4个波长位移。结论薄荷醇可能是通过改变角质层中脂质的构象,使角质层脂质双分子层的流动性增加、有序致密结构改变,降低皮肤屏障作用,从而使药物的透过性增加。
