An isotope label method for empirical detection of carbonic anhydrase in the calcification pathway of the coccolithophore Emiliania huxleyi
An isotope label method for empirical detection of carbonic anhydrase in the calcification pathway of the coccolithophore Emiliania huxleyi
复制标题
DOI：
10.1016/j.gca.2020.09.008
复制
发表时间：
2021
影响因子：
5
通讯作者：
Hongrui Zhang;S. Blanco-Ameijeiras;B. Hopkinson;S. Bernasconi;Luz María Mejía;Chuanlian Liu;H. Stoll
中科院分区：
文献类型：
--
作者：
Hongrui Zhang;S. Blanco-Ameijeiras;B. Hopkinson;S. Bernasconi;Luz María Mejía;Chuanlian Liu;H. Stoll
球石生物体是一类广泛分布于海洋中的浮游植物，它们分泌被称为球石的胞外方解石平板。近年来，球石越来越多地被用作地球化学、生态学和古气候研究的档案。球石为基础的地球化学指标的有力应用取决于对碳获取策略和钙化碳供应途径的了解。碳酸酐酶(CA)在水生藻类的富碳机制S以及潜在的钙化过程中起着重要作用。然而，很难独立评估CA在光合作用和钙化作用的碳供应中的作用。为了填补这一空白，我们探索了一种新的方法来检测球虫体内的CA活性。为了实现这一点，用氧和碳同位素标记的溶解无机碳(DIC)培养球石菌体。通过利用氧和碳同位素与海水的不同行为，这种双标记方法可以阐明CA活性在钙化过程中的意义。将该方法应用于玉米草的研究表明，CA存在于钙化过程中，高CO2处理和低CO2处理的CA活性没有显著差异。而在低CO2处理下，E。胡克斯利提高了细胞膜和叶绿体膜上的碳酸氢根泵出速率。这一新的方法可以在未来对其他种类的球石生物进行研究，并有可能扩大我们对球石氧同位素生命效应的认识。
Coccolithophores are a group of phytoplankton widely distributed in the ocean, which secrete extracellular calcite plates termed coccoliths. Coccoliths have been increasingly employed as an archive for geochemical, ecological and paleoclimate studies in recent years. A robust application of coccolith-based geochemical proxies relies on understanding the carbon acquisition strategies and the pathways of carbon supply for calcification. Carbonic anhydrase (CA) plays important roles in the carbon concentrating mechanism s of aquatic algae and potentially also in calcification. However, it is difficult to independently assess the role of CA in carbon supply for photosynthesis versus calcification. To fill this gap, we explored a new method to detect the CA activity inside coccolithophore. To achieve this, coccolithophores were cultured with oxygen and carbon isotope labeled dissolved inorganic carbon (DIC). By exploiting the different behavior of oxygen and carbon isotopes with (sea)water, this double label method can elucidate the significance of CA activity in the calcification pathway. Application of this method toEmiliania huxleyishows that CA is present in the calcification pathway, and that there is no significant difference in the CA activity between a high and low CO2treatment. However, under low CO2treatmentE. huxleyienhanced the bicarbonate pumping rate on both cell and chloroplast membranes. This novel method could be performed on other species of coccolithophores in the future and have a potential to extend our knowledge on coccolith oxygen isotope vital effects.