Rivière M E, Arrio B, Steffan I, Molitor V, Kuntner O, Peschek G A
Institute of Physical Chemistry, University of Vienna, Austria.
Arch Biochem Biophys. 1990 Jul;280(1):159-66. doi: 10.1016/0003-9861(90)90531-3.
Photoautotrophically growing cultures of the freshwater cyanobacterium Anacystis nidulans (Synechococcus sp.) became adapted to the presence of 0.4-0.5 M NaCl in the growth medium (about seawater level) with a lag phase of 2 days after which time the growth rate resumed at 80-90% of the control. Major changes in structure and function of the plasma membranes (and, to a much lesser extent, of the thylakoid membranes) were found to accompany the adaptation process. Plasma and thylakoid membranes were separated from crude cell-free extracts of French pressure cell-treated Anacystis by discontinuous sucrose density gradient centrifugation and purified by repeated recentrifugation on fresh gradients. Concentrations of copper, iron, calcium, and magnesium ions were determined by inductively coupled plasma atomic emission spectrometry with EDTA-washed and dialyzed membrane preparations; salt adaptation was found to increase (decrease) the concentration of membrane-bound calcium in plasma (thylakoid) membranes, qualitatively reciprocal results being obtained for magnesium. Levels of plasma membrane-bound copper and iron roughly tripled during the adaptation process; by contrast, corresponding effects on thylakoid membranes were negligible. The size of the membrane vesicles was measured by quasi-elastic laser light-scattering and the electric surface charge of the membranes was measured by laser Doppler velocimetry. Salt adaptation decreased the mean diameter of plasma membrane vesicles to a much higher extent than that of thylakoid membrane vesicles. Overall surface charge densities of resting vesicles were only slightly affected by the salt treatment as was also seen from titration of the electrophoretic mobility of the vesicles with electrolytes. Yet, induction of (photosynthetic or respiratory) electron transport provoked a charge separation across the membrane which was easily measurable in terms of electrophoretic mobility. The results will be discussed with particular emphasis on the stimulated cytochrome c oxidase activity of plasma (but not thylakoid) membranes from salt-adapted cells compared to control cells and also with respect to the decreased ion permeability of the plasma membrane of salt grown cells.
淡水蓝藻集胞藻（聚球藻属）在光自养条件下生长的培养物，在生长培养基中适应了0.4 - 0.5 M NaCl（约海水盐度水平）的存在，有2天的滞后期，此后生长速率恢复到对照的80 - 90%。发现质膜（以及在小得多的程度上类囊体膜）的结构和功能的主要变化伴随着适应过程。通过不连续蔗糖密度梯度离心从经法国压榨细胞处理的集胞藻的粗无细胞提取物中分离质膜和类囊体膜，并通过在新鲜梯度上重复再离心进行纯化。用经EDTA洗涤和透析的膜制剂，通过电感耦合等离子体原子发射光谱法测定铜、铁、钙和镁离子的浓度；发现盐适应增加（降低）了质膜（类囊体膜）中膜结合钙的浓度，镁的结果在性质上相反。在适应过程中，质膜结合的铜和铁水平大致增加了两倍；相比之下，对类囊体膜的相应影响可忽略不计。通过准弹性激光光散射测量膜囊泡的大小，通过激光多普勒测速法测量膜的表面电荷。盐适应使质膜囊泡的平均直径减小的程度比类囊体膜囊泡大得多。静息囊泡的总表面电荷密度仅受到盐处理的轻微影响，这也从用电解质滴定囊泡的电泳迁移率中可以看出。然而，（光合或呼吸）电子传递的诱导引发了跨膜的电荷分离，这可以通过电泳迁移率很容易地测量。将特别强调与对照细胞相比，盐适应细胞的质膜（而非类囊体膜）中受刺激的细胞色素c氧化酶活性，以及盐生长细胞的质膜离子渗透性降低，来讨论这些结果。
