查询词典 cyclobutane

DATA SYNTHESIS: With the increase of ultraviolet radiation caused by environmental pollution, DNA in human epidermal cells is damaged. Cyclobutane pyrimidine dimmer and 6-4 photoproducts are the main forms of DNA lesions.

资料综合：环境污染使得紫外辐射增强，而紫外线辐射对机体表皮细胞的DNA具有损害作用，可导致环丁烷嘧啶二聚体和6-4光产物的形成。

Cyclobutane exists predominantly in a "butterfly" conformation .

环丁烷主要成&蝶式&构象存在。

For Teflon PCB, pyrolysis gas contained high concentration of octafluoro- cyclobutane and low concentration of small molecular fluorocarbon-hydrogen compounds.

Teflon热解气体产物主要为八氟环丁烷以及其他小分子碳氟氢烷烃化合物。

Keywords: DNA photoreactivation; CPD photolyase; tryptophan; electron transfer; cyclobutane pyrimidine dimer

中文关键词： DNA光复活；CPD光解酶；色氨酸；电子转移；嘧啶二聚体

Objective To observe the production and removal of photo-product, cyclobutane pyrimidine dimers, in HaCaT cells induced by UVB irradiation and intervention effect of ligustrazine, and to investigate its photo-protective mechanisms on HaCaT cells damaged from UVB irradiation.

目的观察中波紫外线辐射后永生化角质形成细胞株中光产物环丁烷嘧啶二聚体的产生和清除情况，观察川芎嗪对UVB辐射后细胞光产物的影响并探讨其保护作用机制。

In order to mimic this repair process of apoenzyme, we synthesized two model compounds, in which tryptophan and/or tyrosine was covalently linked to cyclobutane thymine dimer, and measured the splitting quantum yield of dimer under 295 nm light. By investigating the photosensitized splitting properties of the dimer, some new insights into the intramolecular electron-transfer process were gained.

为了模拟酶蛋白的这一修复过程，合成了色氨酸和/或酪氨酸与胸腺嘧啶二聚体共价连接的化合物，作为酶-底物复合物的模型，研究了它们在295 nm光照射下氨基酸残基光敏化二聚体裂解的性质，测定了二聚体裂解量子产率，获得一些新的结果并对其进行了分析。

UV-B radiation during the cell cycle induced accumulation of cyclobutane pyrimidine dimers.

单细胞凝胶电泳检测结果表明，UV-B辐射引起拟南芥根尖细胞内积累大量的环丁烷嘧啶二聚体。

Ozone College depletion in stratosphere has led to the increase of solar UV-B radiation reaching to the earth surface, which would damage DNA of plant epidermal cells and produce cyclobutane pyrimidine dimmers (CPD and 6-4 photoproducts.

臭氧衰减导致地表紫外辐射增强，而紫外线辐射对植物表皮细胞的DNA具有损害作用，可导致环丁烷嘧啶二聚体和6，4-光产物的形成。

For example, cyclobutane pyrimidine dimers and pyrimidine-(6-4)-pyrimidones photoproducts [(6-4) PPs] etc. In general, the normal person can repair damaged DNA by reconstructive mechanism of DNA, what is called nucleotide excision repair.

一般正常人，可利用所谓的nucleotide excision repair之DNA修复机制，修补损伤的DNA，但如果此修复机制因基因突变，造成其功能性丧失，无法修复DNA时，即形成所谓的著色性乾皮病。

What\'s more, different intervals of UV have their own characters in influencing DNA: the damage to some bases by UVA may be more serious than that by UVB, and UVB did more severe damage to some deoxyribose than UVA; however, as far as the pyrimidine bases are concerned, the damage by UVB is by far more serious than that by UVA. These results may indicate that there are preferential damaging sites on DNA molecules caused by UVA and UVB irradiation. Moreover, with UVA or UVB irradiation for a long time, the photoreactivation of DNA occurred. The serious damage to deoxyribose and bases by UVB and UVC may confirm the conformation of cyclobutane pyrimidine dimers and (6-4) photoproducts.

而不同波段紫外辐射对DNA的损伤各具特点并且差异明显，UVA对一些碱基的损伤比UVB要严重，而UVB在对脱氧核糖和磷酸盐的损伤上又比UVA要严厉，但就嘧啶碱基来说，UVB对它的损伤远大于UVA，这似乎表明了不同的紫外波段对生物大分子DNA的损伤是有选择性的。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。