Mikhaĭlov V M, Zhestianikov V D, Savel'eva G E
Institute of Cytology RAS, St. Petersburg.
Tsitologiia. 2003;45(4):418-21.
We studied the action of saline extracts of ventricle myocard (EM) of C57BL and mdx mice on DNA structure and repair of one-strand breaks of DNA in a modelling system. The system involves DNA repair in E. coli WP2 cells after gamma-irradiation. Using standard technique, DNA reparation was estimated on measuring the speed of E. coli DNA sedimentation in alkaline sucrose gradients. It was shown, that EM of C57BL or mdx mice exerted no influence on DNA repair, which was completely declined within 60 min with EM present in the growth medium of permeabilized E. coli. Addition of C57BL mice EM into lytic solution does not accelerate DNA sedimentation of nonirradiated E. coli. At the same time, EM of mdx mice sharply accelerates DNA sedimentation of nonirradiated E. coli reducing DNA molecular weight from 200 x 10(6) to 135 x 10(6) Da. At entering in the lytic solution the EM of mdx mice also slows down E. coli DNA repair after gamma-irradiation. It is supposed, that EM of mdx mice may contain a factor(s) damaging DNA in the E. coli lysate and presumably slowing down DNA reparation after gamma-irradiation. Russian Foundation of Basic Research Grants 99-04-49390, 02-04-49870 and 00-04-49390.
我们在一个模拟系统中研究了C57BL和mdx小鼠心室心肌盐水提取物（EM）对DNA结构以及DNA单链断裂修复的作用。该系统涉及γ射线照射后大肠杆菌WP2细胞中的DNA修复。采用标准技术，通过测量碱性蔗糖梯度中大肠杆菌DNA的沉降速度来评估DNA修复情况。结果表明，C57BL或mdx小鼠的EM对DNA修复没有影响，在透化大肠杆菌生长培养基中存在EM的情况下，DNA修复在60分钟内完全下降。将C57BL小鼠的EM添加到裂解液中不会加速未辐照大肠杆菌的DNA沉降。同时，mdx小鼠的EM会显著加速未辐照大肠杆菌的DNA沉降，使DNA分子量从200×10⁶Da降至135×10⁶Da。在进入裂解液时，mdx小鼠的EM也会减缓γ射线照射后大肠杆菌的DNA修复。据推测，mdx小鼠的EM可能含有一种在大肠杆菌裂解物中破坏DNA的因子，并且可能会减缓γ射线照射后的DNA修复。俄罗斯基础研究基金会资助项目99 - 04 - 49390、02 - 04 - 49870和00 - 04 - 49390。
