Phenotypic and genetic analysis of "Chameleon," a paramecium mutant with an enhanced sensitivity to magnesium.
Phenotypic and genetic analysis of "Chameleon," a paramecium mutant with an enhanced sensitivity to magnesium.
复制标题
“变色龙”的表型和遗传分析，一种对镁敏感性增强的草履虫突变体。
DOI：
10.1093/genetics/146.3.871
复制
发表时间：
1997
期刊：
影响因子：
3.3
通讯作者：
Hammond,JA
中科院分区：
文献类型：
--
作者：
Preston,RR;Hammond,JA
本文报道了四脲草履虫（Parameciumtetraurelia）对镁敏感性增强的突变株。这些新的“变色龙”突变体是由单一基因座Cha的部分或共显性突变引起的。而野生型响应于5 mmMg 2+向后游泳10-15秒，Chamutants响应于向后游泳10 - 30秒。电生理学分析表明，这种行为可能是由于膜激发后Mg 2+特异性离子电导失活的速率减慢所致。这与观察到的Chamutants对镍中毒的敏感性增加一致，因为Ni 2+也能够通过该途径进入细胞。更广泛的行为分析表明Chacells也对Na+过度反应，但没有证据表明细胞内Ca 2+稳态的缺陷可能导致Mg 2+和Na+电导的同时增强。Chalocus可能编码Mg ~（2+）和Na ~+渗透性的特异性调节因子。
Three mutant strains ofParamecium tetraureliawith an enhanced sensitivity to magnesium have been isolated. These new“Chameleon”mutants result from partial- or codominant mutations at a single locus,Cha. Whereas the wild type responded to 5 mmMg2+by swimming backward for 10–15 sec,Chamutants responded with ∼30 sec backward swimming. Electrophysiological analysis suggested that this behavior may be caused by slowing in the rate at which a Mg2+-specific ion conductance deactivates following membrane excitation. This would be consistent with an observed increase in the sensitivity ofChamutants to nickel poisoning, since Ni2+is also able to enter the cellviathis pathway. More extensive behavioral analysis showed thatChacells also overresponded to Na+, but there was no evidence for a defect in intracellular Ca2+homeostasis that might account for a simultaneous enhancement of both the Mg2+and Na+conductances. The possibility that theChalocus may encode a specific regulator of the Mg2+- and Na+-permeabilities is considered.