摘要
绿豆下胚轴切段经红光处理后10min,其线粒体的Ca^(2+)积累下降15％,Ca^(2+)-ATPase 及 Mg^(2+)-ATPase活性也分别下降29％和10％,切段CaM含量增加近1倍。Ca^(2+)存在时,红光能促进线粒体NAD 激酶活性。说明Ca^(2+)-ATPase及一部分Mg^(2+)-ATPase可作为钙泵控制Ca^(2+)进入线粒体。
With ^(45) Ca^(2+)-transport assay,the effect of red light (R) on calciumaccumulation in mitochondria isolatedfrom hypocotyl segments of 3-day-oldetiolated seedlings of mung bean(Phaseolus radiatus) was investigated.Immediately after red light irradiation,the active accumulation of Ca^(2+) in mi-tochondria was the same as that fromunirradiated segments. 10 min later,however, the uptake of calcium ion bymitochondria from R-irradiated seg-ments was lowered by 15%. More-over, since calcium accumulation inmitochondria needed energy, the activ-ities of ATPase in mitochondria wereexamined. The results demonstratedthat, 10 min after red light irradia-tion, the activities of Ca^(2+)-ATPaseand Mg^(2+)-ATPase declined by 29%and 10%, respectively. It seemed thatCa^(2+)-ATPase and part of Mg^(2+)-AT-Pase acted as calcium ion pumps regu-lating Ca^(2+) accumulation in mitochon-dria. In addition, CaM content in R-irradiated sgements was 95% higherthan that in the control, when the seg-ments were isolated 10 min after treat-ment. The activity of NAD kinase locat-ed in mitochondria was stimulated byred light when isolated 10 min after ir-radiation and the increase of enzymeactivity reached 17% only when Ca^(2+)(1 mmol/L) was present in the assaymedium. From the data reported here it issuggested that the activities of calciumpumps located in hypocotyl mitochon-dria of mung bean are depressed by redlight irradiation and the accumulationof Ca^(2+) in the mitochondria are de-creased. The concentrations of Ca^(2+)and CaM in the cytosol increased and,as a result, Ca^(2+) (and calmodulin )-de-pendent enzymes such as NAD kinasewhich play an important role in a largenumber of cellular processes are stimu-lated.
基金
国家自然科学基金
关键词
红光
线粒体
NAD激酶
绿豆
ATP酶
red light
mitochondria
Ca^(2+) and CaM
ATPase
NAD kinase
