Proton pumping accompanies calcification in foraminifera.
Proton pumping accompanies calcification in foraminifera.
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DOI：
10.1038/ncomms14145
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发表时间：
2017-01-27
影响因子：
16.6
通讯作者：
Kitazato H
中科院分区：
文献类型：
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作者：
Toyofuku T;Matsuo MY;de Nooijer LJ;Nagai Y;Kawada S;Fujita K;Reichart GJ;Nomaki H;Tsuchiya M;Sakaguchi H;Kitazato H
据广泛报道，正在进行的海洋酸化降低了钙化海洋生物产生贝壳和骨骼的能力。虽然酸化导致的溶解增加在很大程度上是一个无机过程，但生物矿化的强大生物控制会影响钙化，因此使预测海洋钙化者的反应变得复杂。在这里，我们表明，钙化是由细胞质内碳酸氢盐快速转化为碳酸盐所驱动的，这是通过主动向外泵入质子实现的。此外，这种质子通量在很大范围的二氧化碳水平上保持不变。我们进一步证明V型H+ATPase负责质子通量，从而导致钙化。由于质子泵送，碳酸氢盐在外部转化为二氧化碳，这意味着生物矿化不依赖于碳酸盐离子的可用性，但总溶解的二氧化碳可能不会减少钙化，从而潜在地维持目前全球海洋碳酸盐的产量。尽管它们在海洋CaCO3生产中发挥了作用，但对有孔虫中负责钙化的生理过程知之甚少。作者指出，钙化是由细胞质内碳酸氢盐快速转化为碳酸盐所驱动的，这是通过主动向外泵送质子来实现的。
Ongoing ocean acidification is widely reported to reduce the ability of calcifying marine organisms to produce their shells and skeletons. Whereas increased dissolution due to acidification is a largely inorganic process, strong organismal control over biomineralization influences calcification and hence complicates predicting the response of marine calcifyers. Here we show that calcification is driven by rapid transformation of bicarbonate into carbonate inside the cytoplasm, achieved by active outward proton pumping. Moreover, this proton flux is maintained over a wide range of pCO2 levels. We furthermore show that a V-type H+ ATPase is responsible for the proton flux and thereby calcification. External transformation of bicarbonate into CO2 due to the proton pumping implies that biomineralization does not rely on availability of carbonate ions, but total dissolved CO2 may not reduce calcification, thereby potentially maintaining the current global marine carbonate production. Despite their role in oceanic CaCO3 production, the physiological processes responsible for calcification in foraminifera are poorly understood Here, the authors show that calcification is driven by rapid transformation of bicarbonate to carbonate inside the cytoplasm, achieved by active outward proton pumping.