萱藻丝状体对无机碳的利用

应用pH漂移技术和pH电极法并结合相关抑制剂对萱藻丝状体无机碳的利用进行了研究,并探索了不同浓度CO_2对萱藻丝状体碳酸酐酶(CA)的影响。结果显示,(1)萱藻丝状体pH补偿点为9.21,CO_2补偿点为0.74μmol/L。抑制剂乙酰唑胺(AZ,acetazolamide)对萱藻丝状体pH补偿点无显著影响,作用的前3个小时对无机碳的利用量无抑制作用。抑制剂乙氧苯丙噻唑磺胺(EZ,ethoxyzolamide)和钒酸盐(Van)使萱藻丝状体的pH补偿点均下降到8.82,2种抑制剂作用的前3个小时对无机碳利用量的抑制率分别为55.93%和56.72%。自然条件下萱藻丝状体以游离CO_2和HCO_3~-作为无机碳源,且HCO_3~-的利用依赖于ATP酶和胞内CA。(2)0.35%、0.70%和1.20%的CO_2使萱藻丝状体胞内CA活性分别降低6.29%、17.44%和27.15%,CO_2浓度越高对萱藻丝状体胞内CA活性抑制作用越强。

Utilization of inorganic carbon in filaments of Scytosiphon lomentaria

The utilization of inorganic carbon in filaments ofScytosiphon lomentaria was investigated by pH-drift technique and pH electrode method combined with related inhibitors.The influence of different concentrations of carbon dioxide on the activity of intracellular carbonic anhydrase (CA) was also explored at the same time.The results showed that (1)the pH compensation point of filaments of S.lomentaria was 9.21 and the CO2 compensation point was 0.74 iμmol/L.Acetazolamide (AZ) has no significant influence on the pH compensation and the inorganic carbon uptake amount in the first three hours of the inhibitor experiment.Ethoxyzolamide (EZ)and vanadate (Van) decreased the pH compensation point to the same value 8.82 and the inorganic carbon uptake amount inhibition rates were 55.93％ and 56.72％,respectively,in the first three hours of the inhibitor experiment.Under natural conditions,filaments of S.lomentaria use free CO2 and HCO3 as inorganic carbon source,and the utilization of HCO3-depends on ATPase and intracellular CA.(2) 0.35％,0.70％ and 1.20％ CO2 can inhibit the activity of intracellular CA of filaments of S.lomentaria and the inhibition rates were 6.29％,17.44％ and 27.15％,respectively.The higher CO2 concentration,the stronger inhibition effect of the activity of intracellular carbonic anhydrase.