均匀磁场对DNA复制过程的影响初探及其发生装置的设计

【作者】 周建宏；

【导师】 齐浩；

【作者基本信息】 陕西师范大学 ， 生物物理学， 2008， 硕士

【摘要】 随着电磁场对人类生存环境污染的加重,电磁场可能对生物体产生的生物效应的研究日益引起科研人员重视。由于人们所处的生存环境中电磁场的多样性,其对生物体的生物效应也非常复杂,其中电磁场对细胞周期和DNA损伤的影响研究是电磁场生物效应研究的重要问题专一。不同形式的磁场处理成骨细胞,研究者发现磁场处理后的成骨细胞周期改变,S期细胞百分比均明显增高,同时观测到DNA合成速度加快,于是研究者推测细胞的DNA合成受到磁场的影响和调节,导致其合成速度加快,从而出现了S期细胞数增多,但磁场对DNA合成速度的影响机制尚不清楚。文献报道了工频磁场会引起上皮细胞DNA双链断裂,推测磁场影响体内的生物化学过程级联放大,间接损伤DNA,同样其具体机制尚不明确。为了研究磁场对DNA的合成速度和DNA双链断裂的影响,我们选择比较简单的均匀磁场,从理论上探讨了此种磁场对DNA合成速度和DNA断链的影响,得到其合成速度改变和双链断裂程度与磁场强度大小有关。为了进一步验证理论推导的结论,需要设计一个强度可调的均匀磁场发生装置,并能控制磁场区的温度,本文结合相关知识,设计了实验所需的磁场发生装置。细胞在S期的主要工作是进行DNA的复制。在DNA复制解旋的过程中,随着复制叉的前进,其前端DNA分子将不断产生扭力,为了释放积累起来的扭力,复制叉前端的双链DNA分子会出现比较特殊的运动形式,从而保证DNA复制的正常进行。生物DNA大分子外侧是带负电荷的,当其复制在磁场中进行时,会受到洛仑兹力的作用,导致DNA合成速度改变,从而DNA分子的整个复制过程会受到磁场的干扰,细胞周期也会随之改变。而且在此过程中,由于DNA单链受到洛仑兹力的作用,会偏离原来路径,从而导致DNA链的断裂。本文从磁生物效应研究小组观察到的现象出发,结合生物大分子DNA复制的具体特征,从理论上讨论了均匀磁场对DNA复制过程的具体影响,结果发现均匀磁场会使DNA的合成速度增加,与此同时致使DNA双链断裂。目前,为了能深入研究电磁场对细胞的作用机制,研究者常采用形式比较简单的磁场作为外界的干扰电磁场,比如:恒定、交变、脉冲和高频磁场。由于实验的需要,研究人员常用的磁场发生装置有:永磁铁、电磁铁、亥姆霍兹线圈和螺线管。其中永磁铁能够提供强度最大为1特斯拉左右的静磁场,亥姆霍兹线圈和螺线管可提供交变磁场或相对均匀的磁场,也可用螺线管提供强度为10特斯拉左右的超强静磁场,电磁铁则可产生强度为几百毫特斯拉或特斯拉级的静磁场。各个磁场发生装置都有一定的适用范围,本文从物理学角度,阐述了磁生物效应研究中常见磁场发生装置的特性,并从磁生物学的研究角度出发,根据实验要求,设计了一个实用性比较强的均匀磁场发生装置,对该装置的磁场区域的温度控制给出了一个解决方案。通过计算机对实际设计模型的模拟,发现此磁场发生装置产生的磁场与预期结果基本一致,通过对实际模型的温度检测,证实了温控方案实际可行。设计的均匀磁场发生装置由电源、螺线管、水循环温控装置等部分组成,重点介绍了由通电螺线管提供的磁场的特性、水循环温控装置的设计。更多还原

【Abstract】 With the pollution of electromagnetic fields on human existence environmental aggravating, scientific research are very interest in the possible biological effects of electromagnetic fields on the organisms. As the living environment where people are in the field of diversity, its effect on the biological organisms are very complex, which the effect on the cell cycle by electromagnetic fields is one of the important issues.When osteoblast were cultured and put in different forms of magnetic field,the researchers found that the cell cycle were changed, S-phase percentage were significantly higher as compared with control, but the specific mechanism of the effect on the cell cycle by magnetic field is not clear. The researchers speculate that the cell DNA synthesis is impact and regulated by the magnetic field, which leading to its synthesis becoming faster, thus the cells in S phase increased, but the speculate lack of firm evidence. The paper reported frequency magnetic field can give rise to epithelial cell DNA double-strand breaks, speculated that the magnetic field affect the biochemical and enlarge the process, indirectly damage DNA, but the specific mechanism is not yet clear.. In order to explore the effect on DNA synthesis and DNA double-strand breaks by magnetic field, We chose a relatively simple uniform magnetic field, study the affect on DNA synthesis and DNA double-strand breaks by such magnetic field, conclused that this impact related to magnetic field strength. In order to verify the conclusions, need to design a uniform magnetic field strength devices, and can control the temperature of the magnetic field area. this combination of knowledge, we related knowledge, and design the magnetic field devices.The main task of S-phase cells is DNA replication. In the process of DNA replication rotation, with the advance copy fork, front-end DNA molecule will produce torque, in order to release the accumulated torque, the double-stranded DNA molecules which is the front fork will appear special forms of exercise so as to release torque. and ensure the normal DNA replication. DNA is the biological macromolecules,negatively chargedthe on lateral, when the copy process been in a magnetic field, that will be the role of Lorentz force, which leading to changes in speed of DNA synthesis and thus the entire DNA molecule replication process will be interference, cell cycle will also change. On the basis of the phenomenon observed by the biological effects of magnetic team,and combination of the specific characteristics of DNA replication, This article theoretically discussed the affects on the uniform magnetic field on the DNA replication process,and found that uniform magnetic field will increase the speed of DNA synthesis, at the same time result in changes in the structure of DNA.At present, in order to in-depth study the mechanism of the affect on organisms by electromagnetic fields , the researchers often use relatively simple form of the magnetic field as outside interference magnetic fields, such as: static magnetic fields, alternating magnetic fields, pulse magnetic fields and high-frequency magnetic field. with the need, the researchers used are: permanent magnets,electromagnetic Helmholtz coils and solenoids as magnetic field devices. Permanent magnet can provide for a maximum intensity of the magnetic field around Tesla, Helmholtz coils and solenoids can provide alternating magnetic field or relatively uniform magnetic field, and solenoids can also be used to provide strength for the solenoid around 10 Tesla. Various magnetic field devices have a certain scope, this article from the perspective of physics, analyse the characteristics of the each device, with magnetic characteristics of each and magnetobiology research, we summed up a more practical magnetic field devices, According to the experiment requirements, design a practical magnetic field devices which can provide uniform magnetic fields, and take a solution which can control the temperature of the magnetic field of regional. Through computer simulation model,we find that the magnetic field in the device field is consistent with the expected results, through the actual model of temperature detection, confirmed the temperature control is practical. The uniform magnetic field devices is made up of power, solenoids, the water cycle, focusing on the solenoid and the water cycle temperature control device design.更多还原