BIOPHYSICS: L URIA AND EXNER THE INACTIVATION OF BACTERIOPHAGES BY X-RA YS- INFLUENCE OF THE MEDIUM
BIOPHYSICS: L URIA AND EXNER THE INACTIVATION OF BACTERIOPHAGES BY X-RA YS- INFLUENCE OF THE MEDIUM
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生物物理学：L URIA 和 EXNER 通过 X 射线灭活噬菌体 - 介质的影响
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
Frank M. Exner
中科院分区：
文献类型：
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作者：
Frank M. Exner
最近发表了几项关于X射线灭活噬菌体的研究。Woilman和Lacassagne的定性实验表明，悬浮在肉汤中的不同细菌的X射线灵敏度随着它们的颗粒大小而增加，颗粒大小由超滤和离心确定。2 Holweck，Luria和Wollman分析了X射线和α颗粒对C16噬菌体的灭活，并根据“命中理论”解释了他们的结果。Lea对相同的数据进行了进一步的讨论。3我们用X射线对一系列噬菌体（3 K，C16，C13，P28）进行了实验，其中一些已经由Elford测量。2在所有实验中，噬菌体颗粒的浓度都是通过噬菌斑计数方法确定的。在赛璐珞管中照射样品，并仔细注意X射线剂量测量。所有暴露均使用相同的X射线发生器。技术细节将在稍后出版的完整说明中描述。1.当在原始滤液或肉汤稀释液中照射噬菌体时，结果（图1A和1B）显示，（a）灭活曲线（剩余噬菌体的百分比作为以r测量的X射线剂量的函数）在其路径的第一部分是指数的（半对数图中的直线）。当剂量变得非常高时（图2），灭活率显示出增加，然而，这是如此轻微以至于仅由于在噬菌体测定中获得的高精度而可检测到。在Exner和Zaytzeff-Jern的实验中也发现了高剂量下灭活率的增加，这可能是由于某些不同类型的效应叠加在主要灭活过程上造成的。我们希望确定这种影响的性质。我们跟踪灭活至滴度降低2 X 10-7倍，并始终发现一致的可重现结果。灭活是X射线总剂量的函数，而不是剂量率的函数（无“时间因素”）。由给定剂量产生的部分灭活与照射期间噬菌体悬浮液的浓度无关。北纬370度A. S.
Several studies on the inactivation of bacteriophages by x-rays have recently been published.' Qualitative experiments of Woilman and Lacassagne have shown that the x-ray sensitivity of different phages suspended in broth increases with their particle size as determined by ultrafiltration and centrifugation.2 Holweck, Luria and Wollman have analyzed the inactivation of C16 phage by x-rays and alpha-particles, and interpreted their results in terms of the "hit theory." Further discussion of the same data has been given by Lea.3 We have carried out experiments with x-rays on a series of bacteriophages (3K, C16, C13, P28), some of which have been measured by Elford.2 In all experiments the concentration of phage particles was determined by the plaque count method. Samples were irradiated in celluloid tubes with careful attention to x-ray dosage measurement. The same x-ray generator was used for all exposures. Technical details will be described in a complete account to be published later. 1. When bacteriophages are irradiated in the original filtrate or in broth dilutions the results (Figs. 1 and 2) can be summarized as follows: (a) The curve of inactivation (percentage of remaining phage as a function of the dose of x-rays measured in r) is exponential in the first part of its path (straight line in semi-logarithmic plot). When the dosage becomes very high (Fig. 2) the rate of inactivation shows an increase, which however, is so slight as to be detectable only because of the high precision obtained in the phage assay. This increase in inactivation rate with high dosage had also been found in the experiments of Exner and Zaytzeff-Jern and is probably due to superposition on the principal inactivation process of some effect of a different kind. We hope to determine the nature of this effect. We have followed the inactivation to a diminution in titer by a factor of 2 X 10-7 and have always found consistently reproducible results. The inactivation is a function of the total dose of x-rays, and not of the dosage rate (no "time factor"). The fractional inactivation produced by a given dose is independent of the concentration of the phage suspension during irradiation. 370 PROC. N. A. S.