[厌氧和好氧培养的鼠伤寒沙门氏菌中H⁺-K⁺交换的性质]

[The nature of H+-K+-exchange in anaerobically and aerobically grown S. typhimurium].

作者信息

Trchunian A A, Ter-Nikogosian V A, Martirosov S M

出版信息

Biofizika. 1987 Jul-Aug;32(4):609-13.

Abstract

H+-K+-exchange via the Trk-like system of K+ accumulation takes place in anaerobically grown S. typhimurium LT-2 with stable ratio of DCC-sensitive ionic fluxes, equal to 2H+ of a cell for one K+ of the medium. This exchange is now observed in the mutant S. typhimurium TH-31 with unfunctional H+-ATPase. H+-K+-exchange in aerobically grown S. typhimurium LT-2 has unstable ratio of ionic fluxes. The rate of K+ uptake in anaerobically grown bacteria is higher than that in the aerobically grown ones. Q10 is about 1.8 both for H+ transfer and K+ uptake in anaerobically grown bacteria, but it is 1.7 and 0.9 respectively in the aerobically grown ones. Delta psi is not changed by different temperatures both in anaerobically and aerobically grown bacteria. The distribution of K+ in anaerobically grown bacteria is higher than 10(3) and the potassium equilibrium potential is much higher than the measured delta psi. In aerobically grown bacteria the distribution of K+ is in good conformity with the measured delta psi. H+ and K+ transport in anaerobically grown cells is likely to proceed by the same mechanism, which includes H+-ATPase and the Trk-like system. In aerobically grown bacteria these transport systems work separately, and the Trk-like system as K+-ionophore serving for K+ uptake across the electrical field on the membrane.

摘要

通过类似Trk的钾离子积累系统进行的H⁺-K⁺交换发生在厌氧生长的鼠伤寒沙门氏菌LT-2中，其DCC敏感离子通量的比例稳定，即每摄入培养基中的1个K⁺，细胞会摄入2个H⁺。现在在具有无功能H⁺-ATP酶的鼠伤寒沙门氏菌突变体TH-31中也观察到了这种交换。需氧生长的鼠伤寒沙门氏菌LT-2中的H⁺-K⁺交换具有不稳定的离子通量比例。厌氧生长细菌中K⁺的摄取速率高于需氧生长细菌。厌氧生长细菌中H⁺转移和K⁺摄取的Q10约为1.8，但需氧生长细菌中分别为1.7和0.9。厌氧生长和需氧生长的细菌中，不同温度均不会改变Δψ。厌氧生长细菌中K⁺的分布高于10³，钾平衡电位远高于测得的Δψ。在需氧生长细菌中，K⁺的分布与测得的Δψ高度一致。厌氧生长细胞中的H⁺和K⁺转运可能通过相同的机制进行，该机制包括H⁺-ATP酶和类似Trk的系统。在需氧生长细菌中，这些转运系统独立工作，类似Trk的系统作为K⁺离子载体，用于K⁺跨膜电场摄取。