The effects of Cu and Fe availability on the growth and Cu : C ratios of marine diatoms
The effects of Cu and Fe availability on the growth and Cu : C ratios of marine diatoms
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DOI：
10.4319/lo.2008.53.6.2451
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发表时间：
2008-11-01
影响因子：
4.5
通讯作者：
Maldonado, Maria T.
中科院分区：
文献类型：
--
作者：
Annett, Amber L.;Lapi, Suzanne;Maldonado, Maria T.
研究了铜（Cu）和铁（Fe）有效性对8种中心硅藻（沿海和海洋菌株）生长速率、细胞Cu含量和稳态Cu吸收率的影响。虽然铁和铜的有效性对沿海和海洋硅藻的生长速率都有显著影响，但铁和铜的有效性与生长速率之间的相互作用仅在海洋硅藻中观察到。利用放射性示踪剂（67）Cu和（14）C测定细胞Cu：碳(C)配额表明，在Cu充足的条件下，海洋硅藻相对于沿海菌株具有更高的Cu: C比率，而不考虑铁的可用性。两个物种（一个海洋物种和一个沿海物种）对铁的需求显著增加，以响应铁的限制，表明这些生物中依赖铜的高亲和力铁吸收系统上调。细胞Cu: C比值的变化伴随着稳态Cu摄取速率的变化。因此，在某些情况下，Cu的摄取速率似乎受到细胞对铁可用性的调节。铜的获取率对铜的变异性也有显著的响应。与无机、游离Cu浓度的变化相比，硅藻对Cu的吸收变化与培养基中总Cu浓度的变化关系更密切，这表明有机Cu配合物可能对硅藻具有生物可利用性。这些发现表明，铜在开阔海域的生物学作用比以前认为的要大。
We investigated the effects of copper (Cu) and iron (Fe) availability on the growth rates, cellular Cu content, and steady-state Cu uptake rates of eight species of centric diatoms (coastal and oceanic strains). Whereas Fe and Cu availability had a significant effect on the growth rates of both costal and oceanic diatoms, an interaction between Fe and Cu availability and growth rates was only observed for the oceanic diatoms. Determination of cellular Cu : carbon (C) quotas using the radiotracers (67)Cu and (14)C revealed that under Cu-sufficient conditions oceanic diatoms had elevated Cu : C ratios relative to coastal strains, regardless of Fe availability. Two species (one oceanic and one coastal) significantly increased their Cu demands in response to Fe limitation, indicating upregulation of the Cu-dependent high-affinity Fe uptake system in these organisms. The changes in cellular Cu : C ratios were accompanied by variations in steady-state Cu uptake rates. Thus, in some cases Cu uptake rates appear to be regulated by the cell in response to Fe availability. Rates of Cu acquisition also responded significantly to Cu variability. The variation in Cu uptake was more closely correlated with changes in total Cu concentration in the medium than in inorganic, free Cu concentrations, implying that organic Cu complexes may be bioavailable to diatoms. These findings indicate a greater biological role for Cu than was previously thought in open ocean regions.