Krystofová S, Varecka L, Betina V
Department of Microbiology, Biochemistry and Biology, Slovak Technical University, Bratislava, Slovakia.
Gen Physiol Biophys. 1995 Aug;14(4):323-7.
The properties of Ca2+ uptake by Trichoderma viride were studied using radionuclide 45Ca2+ in conjunction with the study of effects of agents influencing the Ca2+ homeostasis on the 45Ca2+ uptake, vegetative growth and conidiation. Mycelium of T. viride was found to take up 45Ca2+ in time- and temperature-dependent manner. The 45Ca2+ uptake could be distinguished from the 45Ca2+ binding by the insensitivity to washing with EGTA (ethylene glycol-bis(2-amino ethyl ether)-N,N,N',N'-tetraacetic acid)-containing solution. The 45Ca2+ uptake was only slightly suppressed by the treatment used to de-energize cells. Agents known to influence Ca2+ homeostasis in animal and plant cells were also active in perturbing the Ca2+ homeostasis in T. viride. In this respect, the agents tested had dual (stimulatory or inhibitory) effects on the 45Ca2+ uptake. No clear correlation among the perturbation of the 45Ca2+ uptake and the inhibition of growth and conidiation was found for the group of compounds tested. Sr2+ and Mg2+ inhibited 45Ca2+ uptake but did not inhibit growth and conidiation. Co2+, Cd2+ inhibited both 45Ca2+ uptake and growth. Other agents tested (Cu2+, Ni2+, La3+, dihydropyridines), which inhibited growth of T. viride, induced massive 45Ca2+ uptake by its mycelium. Ba2+ and Mn2+ showed a biphasic effect on 45Ca2+ uptake-inhibition at lower, and stimulation at higher concentrations, but they had only a slight inhibitory effect on the growth or conidiation at higher concentrations. The 45Ca2+ uptake was influenced by addition of monovalent cations to a small extent only. Na+ (up to 75 mmol.l-1), less than K+, slightly suppressed the 45Ca2+ uptake leaving both growth and conidiation unaffected. Upon depriving the fungus of Ca2+ by chelation of extracellular Ca2+ (not Mg2+ or divalent trace metals) by EGTA, which interfered with Ca2+ homeostasis, vegetative growth rate, and starvation-induced conidiation were restricted. These results suggest that the sustained Ca2+ influx occurs across the T. viride plasma membrane which may be a target site for the antifungal action of heavy metal ions, and its perturbation may lead to disturbances in physiological processes including growth and conidiation. The properties of the Ca2+ influx in T. viride observed substantially differ from those observed in animal cells.
利用放射性核素(^{45}Ca^{2 + })，结合研究影响(Ca^{2 + })稳态的试剂对(^{45}Ca^{2 + })摄取、营养生长和产孢的影响，研究了绿色木霉对(Ca^{2 + })的摄取特性。发现绿色木霉的菌丝体以时间和温度依赖性方式摄取(^{45}Ca^{2 + })。(^{45}Ca^{2 + })的摄取可通过对含乙二醇双（2 - 氨基乙醚）- (N)，(N)，(N')，(N')-四乙酸（EGTA）溶液洗涤不敏感来与(^{45}Ca^{2 + })结合区分开来。用于使细胞去能的处理仅轻微抑制(^{45}Ca^{2 + })的摄取。已知影响动物和植物细胞中(Ca^{2 + })稳态的试剂在扰乱绿色木霉中的(Ca^{2 + })稳态方面也具有活性。在这方面，所测试的试剂对(^{45}Ca^{2 + })的摄取具有双重（刺激或抑制）作用。在所测试的化合物组中，未发现(^{45}Ca^{2 + })摄取的扰动与生长和产孢抑制之间存在明显相关性。(Sr^{2 + })和(Mg^{2 + })抑制(^{45}Ca^{2 + })的摄取，但不抑制生长和产孢。(Co^{2 + })、(Cd^{2 + })既抑制(^{45}Ca^{2 + })的摄取又抑制生长。所测试的其他试剂（(Cu^{2 + })、(Ni^{2 + })、(La^{3 + })、二氢吡啶）抑制绿色木霉的生长，却诱导其菌丝体大量摄取(^{45}Ca^{2 + })。(Ba^{2 + })和(Mn^{2 + })对(^{45}Ca^{2 + })摄取呈现双相效应，低浓度时抑制，高浓度时刺激，但它们在高浓度时对生长或产孢仅有轻微抑制作用。单价阳离子的添加仅在很小程度上影响(^{45}Ca^{2 + })的摄取。(Na^{ + })（高达(7 mmol·L^{-1})），小于(K^{ + })，轻微抑制(^{45}Ca^{2 + })的摄取，而生长和产孢均不受影响。通过EGTA螯合细胞外(Ca^{2 + })（而非(Mg^{2 + })或二价痕量金属）剥夺真菌的(Ca^{2 + })，这会干扰(Ca^{2 + })稳态，营养生长速率和饥饿诱导的产孢受到限制。这些结果表明，持续的(Ca^{2 + })流入发生在绿色木霉的质膜上，这可能是重金属离子抗真菌作用的靶位点，其扰动可能导致包括生长和产孢在内的生理过程紊乱。绿色木霉中观察到的(Ca^{2 + })流入特性与动物细胞中观察到的特性有很大不同。
