Gabor M H, Hotchkiss R D
J Bacteriol. 1979 Mar;137(3):1346-53. doi: 10.1128/jb.137.3.1346-1353.1979.
Bacterial protoplast fusion, induced by polyethylene glycol, has been made more regular and convenient by further specification and improvement of various steps in the previously used procedure. These have made it possible to obtain regularly 100% regeneration of Bacillus subtilis cells from protoplasts before treatment with polyethylene glycol and yields of 10 to 75% from polyethylene glycol-treated protoplasts. Genetic recombination frequencies do not increase correspondingly. Also, when regeneration is reduced by various experimental conditions, recombination does not decrease in proportion. It is concluded that regeneration of recombinant-forming cells is independently determined and not closely related to the average regeneration for the population. Kinetic studies with varying individual parental or total protoplast concentrations strongly indicate that protoplast collision and contact is not the limiting factor determining the number of genetic recombinants obtained. Recombination approximates a linear, rather than quadratic, function of the total or of the majority protoplast population present, from which it is concluded that fusion events are always adequate to produce substantially more potential recombinants than are registered. The strong effect of the majority/minority ratio upon the number of minority cells that become recombinant is independent of which parent is in excess. This shows in a direct and physiological way that both parents are equivalent partners in their genetic contributions.
通过对先前使用的程序中的各个步骤进行进一步规范和改进，由聚乙二醇诱导的细菌原生质体融合变得更加规律和便捷。这些改进使得在用聚乙二醇处理之前，枯草芽孢杆菌原生质体能够有规律地实现100%的细胞再生，而经聚乙二醇处理的原生质体的再生率可达10%至75%。遗传重组频率并未相应增加。此外，当各种实验条件导致再生率降低时，重组率并不成比例下降。得出的结论是，形成重组体的细胞的再生是独立确定的，与群体的平均再生率没有密切关系。对不同的单个亲本或总原生质体浓度进行的动力学研究有力地表明，原生质体的碰撞和接触不是决定获得的遗传重组体数量的限制因素。重组接近存在的总原生质体群体或大多数原生质体群体的线性函数，而非二次函数，由此得出结论，融合事件总是足以产生比记录到的潜在重组体数量多得多的数量。多数/少数比例对成为重组体的少数细胞数量有强烈影响，这与哪个亲本过量无关。这以直接和生理的方式表明，两个亲本在遗传贡献方面是等效的伙伴。
