Cold-shock modification of the oxygen enhancement ratio of Escherichia coli cells.
Cold-shock modification of the oxygen enhancement ratio of Escherichia coli cells.
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冷激修饰大肠杆菌细胞的增氧率。
DOI：
10.1080/09553008714551591
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Smith,DS
中科院分区：
文献类型：
--
作者：
Morse,ML;Smith,DS
氧对暴露于电离辐射的大肠杆菌细胞活力的影响已得到大量研究（Johansen等人，1974年; Quintilliani，1979年; Ewing和Powers，1980年）。在氧气存在下，放射敏感性增加，达到给定存活率所需的剂量减少约三倍，已被反复证明。没有系统的研究的影响，实验的变化测量的氧效应是可用的。已经注意到，细胞存活受到辐照前细胞的孵育和培养基经历、所用平板培养基以及辐照后孵育温度的影响。我们在这里报告，快速稀释的指数增长的E。在37 ℃下在冰浴温度缓冲器中进行共培养大大增加了细胞对γ-辐射的敏感性，并减少了氧对存活的差异效应。使用的菌株是AB 1157（thr-1 ara-14 leuB 6 del gp+ proA 62 lacY 1 tsx 33 sup E44 galk 2 lambda rac-hisG 4 rfbD 1 rpsL 31 kdgK 51 xy 115 mtl-1 argE 3 thi-1）和AB 1157的ada突变体，从耶鲁大学大肠杆菌遗传储备中心的Barbara Bachman博士获得，以及W1的非溶原性（lambda）衍生物W1485，原始的K-12菌株使细胞在补充有所需氨基酸（50 μg ml-1）和维生素（1.5 μg ml-1）的Davis基本培养基（DM; Lederberg 1950）或M9培养基（米勒1972）中生长。0µgml-1）。使用DM或M9盐溶液进行稀释。在M9培养基和缓冲液的大多数实验中，MgSO 4浓度增加到5 mm。研究了在37 ℃通气下指数生长的培养物。生长后在550 nm处测定吸光度。通过在缓冲液中稀释并在顶层琼脂（6 g 1-1）中铺板到具有10 g 1-1琼脂的LB平板（米勒1972）上来测量细胞数。通过将37 ℃培养物快速稀释50倍或更多到冰冷的缓冲液中来产生冷休克。除非另有说明，否则将冲击的细胞保持在冰浴温度下，直到照射或铺板。在室温（22-23 ℃）下，将未冲击的细胞以类似的方式稀释到缓冲液中，并保持在该温度下或缓慢冷却。将待辐照的细胞置于冰冷或室温的1.0 ml容量瓶中。氧化细胞悬浮液在22-23 ℃下用空气平衡的缓冲液中.通过用氩气（99.999%）鼓泡10分钟来产生缺氧，然后将烧瓶盖上并密封。在22-23 ℃下的辐照来自于15 Co源（γ射线束150，加拿大原子能有限公司），剂量率为7.5-90戈伊min-1。图1显示了在存在和不存在氧的情况下，菌株AB 1157的细胞在暴露于4000戈伊的γ-辐射后的存活情况。这些细胞在37 ℃下生长，移到室温（22-23 ℃），稀释并在该温度下照射.这些细胞的氧增强比（oer）为2.9，这是本实验室以这种方式处理的典型培养物。文献中报告了类似的观察结果（Quintilliani 1979）。快速稀释到冰冷缓冲液中并在存在/不存在以下条件下照射的细胞的存活率：
The effect of oxygen on the viability of cells of Escherichia coliexposed to ionizing radiation has been much studied (Johansen et al. 1974, Quintilliani 1979, Ewing and Powers 1980). The increased radiosensitivity in the presence of oxygen, approximately a three-fold decrease in dose required to reach a given survival, has been demonstrated repeatedly. No systematic study of the effect of experimental variation on the measurement of the oxygen effect is available. That cell survival is influenced by the incubation and media experiences of the cells prior to irradiation, by the plating medium employed, and the temperature of incubation after radiation exposure has been noted. We report here that rapid dilution of an exponentially growing E. coliculture at 37 C into ice-bath temperature buffer greatly increases cell sensitivity to y-radiation and diminishes the differential effect of oxygen on survival. The strains used were AB1 157 (thr-1 ara-14 leuB6 del gp+ proA62 lacY1 tsx33 sup E44 galk2 lambda rac-hisG4 rfbDl rpsL31 kdgK51 xy115 mtl-1 argE3 thi-1) and the ada mutants of AB1157, received from Dr Barbara Bachman, Coli Genetic Stock Center of Yale University, and W1485, a non-lysogenic (lambda) derivative of Wl, the original K-12 strain. Cells were grown in Davis minimal medium (DM; Lederberg 1950) or M9 medium (Miller 1972) supplemented with the required amino acids (50 µg ml-I) and vitamins (1. 0µgml-1). DM or M9 salt solutions were used for dilutions. In most experiments with M9 medium and buffer the MgSO4 concentration was increased to 5 mm. Exponentially growing cultures with aeration at 37 C were studied. Growth was followed by absorbance at 550 nm. Cell numbers were measured by diluting in buffer and plating in top agar (6 g 1-1) onto LB plates (Miller 1972) with 10 g 1-1 agar. Cold shock was produced by a quick 50-fold or more dilution from a 37 C culture into ice-cold buffer. Shocked cells were kept at ice-bath temperature unless otherwise stated until irradiation or plating. Cells which were not shocked were diluted in a similar manner into buffer at room temperature (22-23 C) and either held at that temperature or cooled slowly. Cells to be irradiated were placed in ice-cold or room temperature 1.0 ml volumetric flasks. Oxic cell suspensions were in buffers that had been equilibrated with air at 22-23 C. Anoxia was produced by bubbling with argon (99.999 per cent) for 10 min, the flasks were then capped and sealed. Irradiation at 22-23 C was from a" Co source (Gamma Beam 150, Atomic Energy of Canada, Ltd) at dose rates of 7.5-90 Gy min-1. The survival, in the presence and absence of oxygen, of cells of strain AB 1157 after exposure to 4000 Gy of y-radiation is illustrated in figure 1. These cells were grown at 37 C, removed to room temperature (22-23 C), diluted and irradiated at that temperature. Those cells had an oxygen enhancement ratio (oer) of 2.9, which it typical of cultures handled in this way in this laboratory. Similar observations are reported in the literature (Quintilliani 1979). Survival of cells which were rapidly diluted into ice-cold buffer and irradiated in the presence/absence of
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DOI：
--
发表时间：
1969
期刊：
影响因子：
--
作者：
Mikio Sato;H. Takahashi
通讯作者：
H. Takahashi
热疗和电离辐射之间的协同作用。
影响因子：
2.6
作者：
J. Holt;R. W. Stanford
通讯作者：
R. W. Stanford
大肠杆菌 K1060 的辐射杀灭：膜流动性、低温和局部麻醉剂的作用。
DOI：
10.1080/09553008014550641
发表时间：
1980
期刊：
International journal of radiation biology and related studies in physics, chemistry, and medicine
影响因子：
--
作者：
M. Yatvin;B. J. Schmitz;W. Dennis
通讯作者：
W. Dennis
临床放射增敏新方法的可行性研究：低温和高压氧结合药物血管舒张。
DOI：
10.1259/0007-1285-59-707-1093
发表时间：
1986
期刊：
The British journal of radiology
影响因子：
--
作者：
R. Sealy;G. Harrison;D. Morrell;J. Korrûbel;A. Gregory;L. Barry;G. Blekkenhorst;E. Hering;A. Fataar;J. Boniaszczuk
通讯作者：
J. Boniaszczuk
氧气在促进 X 射线诱导的环状噬菌体 lambda DNA 中的单链断裂以及杀死大肠杆菌的辐射敏感突变体方面的有效性。
影响因子：
3.4
作者：
I. Johansen;Robert A. Gulbrandsen;R. Pettersen
通讯作者：
R. Pettersen