激光在农业和医疗等方面已有广泛应用,并且取得增产和一定疗效,但也有费介现象(暂称后继效应或潜在效应)。激光辐照生物体虽然是局部的有限时间,但对由多种生物大分子组成的生物体的影响可能是综合的。为了探索激光生物学效应的分子机理...激光在农业和医疗等方面已有广泛应用,并且取得增产和一定疗效,但也有费介现象(暂称后继效应或潜在效应)。激光辐照生物体虽然是局部的有限时间,但对由多种生物大分子组成的生物体的影响可能是综合的。为了探索激光生物学效应的分子机理,以便进一步认识和掌握激光的生物学效应,对激光直接辐照有生物活性的生物大分子—酵母甘露聚糖产生的效应进行电镜扫描观察和紫外及红外光谱法分析研究。实验结果表明:308 nm激光(单脉冲25 m J,33.3 m J^34.4 m J,脉冲频率2次/s)无论是固定辐照时间(45 s)变化样品所置距离,或反之固定样品所置距离(290 mm)改变辐照时间为15 s、30 s、45 s或60 s,都能引起受照样品的结构(构象)变化,特别是糖分子结构中富含的-OH-、CH-OH、-C-O-C--、N-C=O-、C=O等结构部件处的IR谱线对激光能量变化影响敏感。它们既是糖分子内或分子间形成氢键和糖苷键的结构基础部件,又是甘露聚糖(M an-nan)糖基化其他生物大分子进而影响它们在生物信息流中作用的重要结构部件。结果显示糖在激光生物效应中起了不可忽视的作用,这为综合探索激光生物效应分子机理和糖在生物信息传递中的作用提供了重要线索,为选择甘露聚糖作为生物导弹载体提供了参考依据。展开更多
Nanomaterials have attracted considerable interest owing to their unique physicochemical properties.The wide application of nanomaterials has raised many concerns about their potential risks to human health and the en...Nanomaterials have attracted considerable interest owing to their unique physicochemical properties.The wide application of nanomaterials has raised many concerns about their potential risks to human health and the environment.Metal oxide nanopartides（MONPs）,one of the main members of nanomaterials,have been applied in various fields,such as food,medicine,cosmetics,and sensors.This review highlights the bio-toxic effects of widely applied MONPs and their underlying mechanisms.Two main underlying toxicity mechanisms,reactive oxygen species（ROS）-and non-ROS-mediated toxidties,of MONPs have been widely accepted.ROS activates oxidative stress,which leads to lipid peroxidation and cell membrane damage.In addition,ROS can trigger the apoptotic pathway by activating caspase-9 and-3.Non-ROS-mediated toxicity mechanism includes the effect of released ions,excessive accumulation of NPs on the cell surface,and combination of NPs with specific death receptors.Furthermore,the combined toxicity evaluation of some MONPs is also discussed.Toxicity may dramatically change when nanomaterials are used in a combined system because the characteristics of NPs that play a key role in their toxicity such as size,surface properties,and chemical nature in the complex system are different from the pristine NPs.展开更多
文摘激光在农业和医疗等方面已有广泛应用,并且取得增产和一定疗效,但也有费介现象(暂称后继效应或潜在效应)。激光辐照生物体虽然是局部的有限时间,但对由多种生物大分子组成的生物体的影响可能是综合的。为了探索激光生物学效应的分子机理,以便进一步认识和掌握激光的生物学效应,对激光直接辐照有生物活性的生物大分子—酵母甘露聚糖产生的效应进行电镜扫描观察和紫外及红外光谱法分析研究。实验结果表明:308 nm激光(单脉冲25 m J,33.3 m J^34.4 m J,脉冲频率2次/s)无论是固定辐照时间(45 s)变化样品所置距离,或反之固定样品所置距离(290 mm)改变辐照时间为15 s、30 s、45 s或60 s,都能引起受照样品的结构(构象)变化,特别是糖分子结构中富含的-OH-、CH-OH、-C-O-C--、N-C=O-、C=O等结构部件处的IR谱线对激光能量变化影响敏感。它们既是糖分子内或分子间形成氢键和糖苷键的结构基础部件,又是甘露聚糖(M an-nan)糖基化其他生物大分子进而影响它们在生物信息流中作用的重要结构部件。结果显示糖在激光生物效应中起了不可忽视的作用,这为综合探索激光生物效应分子机理和糖在生物信息传递中的作用提供了重要线索,为选择甘露聚糖作为生物导弹载体提供了参考依据。
基金supported by the National Natural Science Foundation of China(21371115,11025526,40830744, 41073073,and 21101104)the National Basic Research Program of China(2011CB933402)+1 种基金the Innovation Program of Shanghai Municipal Education Commission(14YZ025)the Program for Innovative Research Team in University(IRT13078)
文摘Nanomaterials have attracted considerable interest owing to their unique physicochemical properties.The wide application of nanomaterials has raised many concerns about their potential risks to human health and the environment.Metal oxide nanopartides（MONPs）,one of the main members of nanomaterials,have been applied in various fields,such as food,medicine,cosmetics,and sensors.This review highlights the bio-toxic effects of widely applied MONPs and their underlying mechanisms.Two main underlying toxicity mechanisms,reactive oxygen species（ROS）-and non-ROS-mediated toxidties,of MONPs have been widely accepted.ROS activates oxidative stress,which leads to lipid peroxidation and cell membrane damage.In addition,ROS can trigger the apoptotic pathway by activating caspase-9 and-3.Non-ROS-mediated toxicity mechanism includes the effect of released ions,excessive accumulation of NPs on the cell surface,and combination of NPs with specific death receptors.Furthermore,the combined toxicity evaluation of some MONPs is also discussed.Toxicity may dramatically change when nanomaterials are used in a combined system because the characteristics of NPs that play a key role in their toxicity such as size,surface properties,and chemical nature in the complex system are different from the pristine NPs.
