EFFECT OF STREPTOMYCIN ON ESCHERICHIA-COLI
EFFECT OF STREPTOMYCIN ON ESCHERICHIA-COLI
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DOI：
10.1038/185023a0
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发表时间：
1960-01-01
期刊：
影响因子：
64.8
通讯作者：
DAVIS, BD
中科院分区：
文献类型：
--
作者：
ANAND, N;DAVIS, BD
这些论文来自哈佛医学院细菌学和免疫学系。在第一种情况下，据报道，当60微克。/RNL。将链霉素添加到大肠杆菌的增殖培养物中，在矿物质-葡萄糖介质中，核苷酸在不同的情况下被释放，但-对于估计的7个中的一些，数量较大，比最初存在于细胞中的核苷酸多。氨基酸的“排泄”也增加了4倍，浓缩缬氨酸的能力丧失，对柠檬酸盐的渗透性增加。因此，链霉素必须作用于被认为是细胞膜的通透性屏障。氯霉素，20微克。/ml，防止杀菌作用和核苷酸排泄。第二篇论文介绍了链霉素的吸收研究再见。大肠杆菌，用14C标记的链霉素进行。最初摄取非常迅速，在1分钟内完成，之后细胞内容物保持15分钟不变(根据文本：图表中的10分钟)。这大约是核苷酸排泄开始的时候。摄取持续到1小时后，细胞内容物进一步增加约3倍。这种二次摄取归因于第一阶段对细胞膜的破坏所产生的通透性增加。氯霉素的存在阻止了二次摄取，而甲苯或多粘菌素的加入破坏了细胞膜，增加了二次摄取。作者不确定第一阶段对细胞膜的破坏是否是杀菌效应的充分和必要原因，或者这是否必须通过渗透来完成，尽管他们发现耐药突变体具有相同的初始摄取，但没有第二次摄取。这一机制被认为解释了链霉素和其他杀菌剂之间的协同作用，即一种杀菌剂的损伤允许另一种杀菌剂的渗透。
These papers are from the Department of Bacteriology and Immunology, Harvard Medical School. In the first it is reported that when 60 µgm. /rnl. streptomycin is added to multiplying cultures ofEscherichia coliin a mineral-glucose medium, nucleotides are liberated in differing, but-for some of the 7 estimated, large-amounts, greater than those initially present in the cells. There was also a 4-fold increase in the " excretion " of amino acids, a loss of capacity to concentrate valine, and an increased permeability to citrate. Streptomycin must therefore act on a permeability barrier, which is believed to be the cell membrane. Chloramphenicol, 20 µgm. /ml. prevented both bactericidal action and nucleotide excretion.The second paper describes studies of the absorption of streptomycin byE. coli, carried out with streptomycin labelled with14C. There was an initial very rapid uptake, complete within 1 minute, after which the cell content remained stationary for 15 minutes (according to the text: 10 minutes in a chart). This is about the time when nucleotide excretion had been shown to begin. Uptake continued until after 1 hour the cell content had risen further about 3-fold. This secondary uptake is attributed to the increased permeability produced by damage to the cell membrane in the first stage. The presence of, chloramphenicol prevented secondary uptake, and the addition of toluene or polymyxin, which damage the cell membrane, increased it. The authors are uncertain whether damage to the cell membrane in the first stage is " a sufficient as well as a necessary cause of the bactaridal effect ", or whether this has to be completed by penetration, although they found that a resistant mutant had the same initial, but no secondary, uptake. This mechanism is believed to explain synergy between streptomycin and other bactericidal agents, the damage of one permitting penetration by the other.L. P. Garrod.