Dissolved Organic Phosphorus Utilization by Phytoplankton Reveals Preferential Degradation of Polyphosphates Over Phosphomonoesters
Dissolved Organic Phosphorus Utilization by Phytoplankton Reveals Preferential Degradation of Polyphosphates Over Phosphomonoesters
复制标题
DOI：
10.3389/fmars.2018.00380
复制
发表时间：
2018-10-25
影响因子：
3.7
通讯作者：
Duhamel, Solange
中科院分区：
文献类型：
--
作者：
Diaz, Julia M.;Holland, Alisia;Duhamel, Solange
溶解有机磷（DOP）的营养可利用池支持海洋初级生产力在一系列海洋生态系统，但仍然没有得到很好的解决。在这里，模型磷（P）化合物代表海洋DOP的主要PM键类-磷酸单酯（P-O-C）和磷酸酐（P-O-P）-的相对不稳定性进行了评估，在硅藻培养的海链藻属，以及北大西洋西部的沿海现场。在硅藻样品中，最大酶解速率显示，相对于P-单酯腺苷5 '-单磷酸（AMP）和4-甲基伞形酮磷酸（MUF-P），无机三聚磷酸（3 poly-P）的P-酸酐键，其次是腺苷5'-三磷酸（ATP）的P-酸酐键优先降解。与这些速率测量一致，有针对性的蛋白质组学分析表明，硅藻样品中存在的潜在磷酸酶多样性主要由P-酸酐降解酶（无机焦磷酸酶和核苷三磷酸酶）。此外，生物量标准化的ATP降解率总是抑制下P-充满条件下的硅藻文化，但总体P的可用性对3聚P降解的影响是不一致的硅藻菌株，这表明无机聚磷酸盐（聚P）降解可能会持续下去，而不论在海洋环境中的P水平。事实上，大多数实地考察的P-充满沿海北大西洋西部表现出显着较高的最大速率无机聚磷水解相对于P-单酯水解，这在很大程度上是由浮游植物动力学。基于这些结果，P-酸酐的利用可能会导致更大的或甚至更大幅度比P-酯的社区水平的磷需求，浮游植物的生长，初级生产力的可能性，应被考虑。
The nutritionally available pool of dissolved organic phosphorus (DOP) supports marine primary productivity in a range of ocean ecosystems but remains poorly resolved. Here, the relative lability of model phosphorus (P) compounds representing the major PM bond classes of marine DOP - phosphomonoesters (P-O-C) and phosphoanhydrides (P-O-P) - was assessed in diatom cultures of the genus Thalassiosira, as well as coastal field sites of the western North Atlantic. In diatom samples, maximum enzymatic hydrolysis rates revealed that the P-anhydride bonds of inorganic tripolyphosphate (3poly-P), followed by the P-anhydride bonds of adenosine 5'-triphosphate (ATP), were preferentially degraded relative to the P-monoesters adenosine 5'-monophosphate (AMP) and 4-methylumbelliferone phosphate (MUF-P). Consistent with these rate measurements, targeted proteomics analysis demonstrated that the underlying phosphatase diversity present in diatom samples was dominated by P-anhydride degrading enzymes (inorganic pyrophosphatases and nucleoside triphosphatases). Furthermore, biomass-normalized rates of ATP degradation were always suppressed under P-replete conditions in diatom cultures, but the effect of overall P availability on 3poly-P degradation was inconsistent among diatom strains, suggesting that inorganic polyphosphate (poly-P) degradation may persist irrespective of prevailing P levels in the marine environment. Indeed, the majority of field sites examined in the P-replete coastal western North Atlantic exhibited significantly higher maximum rates of inorganic poly-P hydrolysis relative to P-monoester hydrolysis, which was largely driven by phytoplankton dynamics. Based on these results, the possibility that P-anhydride utilization may contribute comparably or even more substantially than P-esters to community-level P demand, phytoplankton growth, and primary productivity should be considered.