Nitrate or ammonium: Influences of nitrogen source on the physiology of a green alga
Nitrate or ammonium: Influences of nitrogen source on the physiology of a green alga
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DOI：
10.1002/ece3.4790
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发表时间：
2019-02-01
影响因子：
2.6
通讯作者：
Spijkerman, Elly
中科院分区：
文献类型：
--
作者：
Lachmann, Sabrina C.;Mettler-Altmann, Tabea;Spijkerman, Elly
在淡水中，藻类物种暴露于不同的无机氮（Ni）源，其掺入不同的生化能量需求。我们假设，由于铵（NH 4+）-使用的能量需求较少，与硝酸盐（NO3-）-使用相反，更多的能量用于其他代谢过程，特别是在CO2-和磷（Pi）限制条件下。因此，我们测试的绿色嗜酸衣原体生长在NH 4+或NO3-CO2和PI供应的协变下的细胞特性的差异，以确定限制，在一个全因子设计。正如预期的那样，结果显示，在低CO2条件下，与用NO3-生长相比，NH 4+生长的细胞的碳固定率更高。NO3-生长的细胞积累了更多的9种分析的氨基酸，特别是在PI限制的条件下，与NH 4+提供的细胞相比。这可能是由于提供了NO3-的细胞中蛋白质合成较慢。与我们的预期相反，与NH 4+生长的细胞相比，NO3-生长的细胞在Pi限制下具有更高的光合效率。总之，在Ni源NH 4+上的生长没有导致明显增强的Ci同化，因为它高度依赖于Pi和CO2条件（充满或有限）。结果可能与C.嗜酸菌只能使用CO2作为其无机碳源。
In freshwaters, algal species are exposed to different inorganic nitrogen (Ni) sources whose incorporation varies in biochemical energy demand. We hypothesized that due to the lesser energy requirement of ammonium (NH4+)-use, in contrast to nitrate (NO3-)-use, more energy remains for other metabolic processes, especially under CO2-and phosphorus (Pi) limiting conditions. Therefore, we tested differences in cell characteristics of the green alga Chlamydomonas acidophila grown on NH4+ or NO3- under covariation of CO2 and Pi-supply in order to determine limitations, in a full-factorial design. As expected, results revealed higher carbon fixation rates for NH4+ grown cells compared to growth with NO3- under low CO2 conditions. NO3- -grown cells accumulated more of the nine analyzed amino acids, especially under Pi-limited conditions, compared to cells provided with NH4+. This is probably due to a slower protein synthesis in cells provided with NO3-. In contrast to our expectations, compared to NH4+ -grown cells NO3- -grown cells had higher photosynthetic efficiency under Pi-limitation. In conclusion, growth on the Ni-source NH4+ did not result in a clearly enhanced Ci-assimilation, as it was highly dependent on Pi and CO2 conditions (replete or limited). Results are potentially connected to the fact that C. acidophila is able to use only CO2 as its inorganic carbon (Ci) source.