Release of genetic transforming agent from pneumococcal cultures during growth and disintegration.
Release of genetic transforming agent from pneumococcal cultures during growth and disintegration.
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DOI：
10.1084/jem.116.4.491
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发表时间：
1962-10-01
期刊：
影响因子：
--
通讯作者：
HOTCHKISS RD
中科院分区：
文献类型：
--
作者：
OTTOLENGHI E;HOTCHKISS RD
研究了由链霉素诱导的裂解物介导的肺炎球菌的遗传转化，以深入了解新释放的转化原理的性质以及供体群体的生理状态对转化过程的影响。研究发现，链霉素可以使敏感细胞的DNA可用于转化其他细胞。还发现在普通培养基中呈指数增长的活肺炎球菌培养物会释放大量具有遗传活性的DNA。这种未经任何药物处理的培养物没有显示出伴随细胞崩解或死亡的证据。单一标记和小连锁群都可以在药物诱导的裂解物和活培养物滤液介导的转化中转移。释放的 DNA 量很少（每毫升少于 0.1 µg），但与可用的总 DNA 相比，这些转化至少与纯化 DNA 介导的转化一样有效。平均受体培养物中高达 1% 的细胞可以通过少量培养液转化。在药物处理和未处理的培养物中，转化活性的量在培养物生长过程中先增加后减少。尽管无法确定生长培养物中转化DNA的来源，但老化药物处理或未处理培养物的转化活性下降归因于脱氧核糖核酸酶的存在。肺炎球菌培养物在指数生长中期释放的这种核酸酶足以导致存在的低浓度的新鲜释放的转化剂的温和降解。活培养物活性转化剂的最大释放与该培养物对外源DNA的最大接受性的发展及时一致。因此，重组体可以从在彼此存在下生长的适当遗传标记菌株中回收。鉴于这些结果，DNA介导的转化似乎有可能在自然界中为某些可能不具有性机制的细菌物种提供或可能已经提供了遗传重组机制。
Genetic transformations of pneumococcus mediated by streptomycin-induced lysates were studied to gain some insight into the nature of freshly released transforming principle, and the influence of the physiologic state of the donor population on the transformation process. It was found that streptomycin could make the DNA of sensitive cells available for transformation of other cells. Living cultures of pneumococcus growing exponentially in ordinary media were also found to discharge significant quantities of genetically active DNA. Such cultures, not treated with any drug, showed no evidence of concomitant cell disintegration or death. Both single markers and small linkage groups could be transferred in transformations mediated by drug-induced lysates and by filtrates of living cultures. The quantity of DNA liberated is small (less than 0.1 µg per ml), but these transformations are at least as efficient as transformations mediated by purified DNA, when compared on the basis of total DNA available. Up to 1 per cent of the cells in an average recipient culture can be transformed by a small quantity of culture fluid. Both in drug-treated and in untreated cultures the amount of transforming activity increased and then decreased during growth of the culture. Although the source of transforming DNA in growing cultures could not be established, the decline in the transforming activity of aging drug-treated or untreated cultures was attributed to the presence of deoxyribonuclease. The release of this nuclease by pneumococcal cultures midway in exponential growth is sufficient to result in a mild degradation of the low concentration of freshly released transforming agent present. Maximal release of active transforming agent by a living culture coincided in time with the development of maximal receptivity to exogenous DNA by that culture. As a result, recombinants could be recovered from appropriately genetically marked strains growing in each other's presence. In view of these results, it seems possible that DNA-mediated transformations might provide, or might have provided, a mechanism of genetic recombination in nature for some bacterial species in which sexual mechanisms may not be available.
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DOI：
10.1084/jem.106.2.247
发表时间：
1957-08-01
期刊：
The Journal of experimental medicine
影响因子：
--
作者：
BRACCO RM;KRAUSS MR;ROE AS;MACLEOD CM
通讯作者：
MACLEOD CM
影响因子：
3.7
作者：
EPHRUSSITAYLOR, H
通讯作者：
EPHRUSSITAYLOR, H
DOI：
10.1099/00221287-19-3-522
发表时间：
1958-01-01
期刊：
JOURNAL OF GENERAL MICROBIOLOGY
影响因子：
--
作者：
CATLIN, BW;CUNNINGHAM, LS
通讯作者：
CUNNINGHAM, LS
影响因子：
56.9
作者：
CATLIN, BW
通讯作者：
CATLIN, BW
DOI：
10.1101/sqb.1951.016.01.032
发表时间：
1951-01-01
期刊：
COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY
影响因子：
--
作者：
HOTCHKISS, RD
通讯作者：
HOTCHKISS, RD