阳离子及ATP对绿豆线粒体膨胀与收缩的影响

本文报道了一价阳离子 K~+、Na~+及两价阳离子 Mg~(++)、Ca~(++)以及 ATP 对绿豆线粒体膨胀和收缩的影响。K~+、Na~+在低渗条件下引起线粒体瞬时的迅速膨胀。在同样离子强度下K~+引起的膨胀大于 Na~+。ATP 和 Mg~(++)能诱发低渗条件下膨胀线粒体的收缩,但对等渗和高渗 KCl 或 Nacl 溶液中膨胀的线粒体无明显作用。生理浓度的 Mg~(++)、Ca~(++)在低渗条件下引起线粒体缓慢的但幅度较大的膨胀,5mmol/l ATP 引起这种膨胀线粒体的部分收缩。1mmol/lca~(++)在含0.125mmol/l KCl 或在含0.25mol/l甘露醇的等渗介质中几乎不引起膨胀,而ATP 促进大幅度膨胀,10mmol/l MgCl_2引起这种膨胀线粒体的部分收缩。2mmol/l MgCl_2在含有0.25mol/l 甘露醇的等渗介质中引起明显膨胀,ATP 促进这种膨胀。0.125mol/lKCl+2mmol/l MgCl_2为肌动蛋白从单体聚合成多聚体所必须的条件。在此条件下,线粒体几乎不膨胀,而加入 ATP 后则促进大幅度膨胀。在电子显微镜下观察了等渗及低渗条件下线粒体形态变化。

THE EFFECTS OF CATION AND ATP ON SWELLING AND CONTRACTION OF MUNG BEAN MITOCHONDRIA

The effects of monovalent cation K~+,Na~+ and divalent cation Mg~(2+),Ca~(2+)(all of these are in choloride)and ATP on the swelling and contraction of isolated mung bean mitochondria have been described.These cations and ATP show different effects in different test medium K~+,Na~+ initiated a rapid and instantaneous swelling of mung bean mitochondria in hy- potonic medium.The degree of swelling decreased with the increase of concentration of KCl or NaCl.ATP and Mg~(2+) can initiate a contraction of the swelling mitochondria in hypotonic medium but there was no effect on the swelling mitochondria in isotonic or hypertonic medium (0.125 mol/l or 0.6 mol/l KCI or NaCI).The degree of swelling in KCl is more than that one in NaCl at the same concentration. Mg~(2+),Ca~(2+) at physiological concentration(2 mmol/l MgCl_2 1 mmol/l CaCl_2)initiated a slower and a greater degree swelling of mung bean mitochondria in hypotonic medium. 5 mmol/l ATP initiated a part of contraction of the swelling mitochondria. 1 mmol/l Ca~(++) initiated a very small swelling of mung bean mitochondria in 0.125 mmol/l KCl or 0.25 mol/l mannitol.5 m mol/l ATP greatly promoted the swelling.10m mol/l MgCl_2 initiated a part of contraction of the swelling. 2m mol/l MgCl_2 initiated an obivious swelling in 0.25mol/l mannitol.5m mol/l ATP promoted the swelling,10m mol/l MgCl_2 initiated a part of contraction of the swelling mito- chondria. 2m mol/l MgCl_2,0.125mol/l KCl,0.25mol/l mannitol all together,which can not initi- ated any swelling of mung bean mitochondria but 5m mol/l ATP greatly promoted the swelling in this condition. The patterns of mung bean mitochondria in different condition have been observed.