Department of Mathematics, Sciences, and Technology, Paine College, 1235 15th Street, Augusta, GA 30901, USA.
Mar Drugs. 2013 Jul 11;11(7):2398-412. doi: 10.3390/md11072398.
Because domoic acid, a neurotoxic secondary metabolite produced by marine diatoms in the genus Pseudo-nitzschia, is hypothesized to be part of a high affinity iron uptake system, we investigated whether domoic acid could improve the competitive ability of Pseudo-nitzschia delicatissima, and whether the availability of iron changed the outcome of competition experiments. We found that domoic acid had a slight negative effect on growth of the diatom Skeletonema marinoi when it was grown in monocultures. However, when S. marinoi was cultured with P. delicatissima the presence of domoic acid resulted in a reduction of S. marinoi cells by up to 38% and an increase in P. delicatissima cell numbers by up to 17% under iron replete conditions. Similar effects were not observed in low iron treatments. Domoic acid was not taken up by P. delicatissima cells. Overall, our results indicate that domoic acid can improve the competitive ability of Pseudo-nitzschia spp. and that iron is likely to be involved. This study provides an unusual example of indirect inhibition of competitor growth mediated by a secondary metabolite.
由于拟菱形藻属海洋硅藻产生的神经毒性次生代谢物软骨藻酸被假设为高亲和力铁摄取系统的一部分，我们研究了软骨藻酸是否可以提高柔弱伪菱形藻的竞争能力，以及铁的可用性是否会改变竞争实验的结果。我们发现，软骨藻酸在单独培养时对海洋硅藻 Skeletonema marinoi 的生长有轻微的负作用。然而，当 S. marinoi 与 P. delicatissima 一起培养时，在铁充足的条件下，软骨藻酸的存在导致 S. marinoi 细胞减少多达 38%，而 P. delicatissima 细胞数量增加多达 17%。在低铁处理中没有观察到类似的效果。软骨藻酸未被 P. delicatissima 细胞吸收。总的来说，我们的结果表明，软骨藻酸可以提高拟菱形藻属的竞争能力，而铁可能参与其中。这项研究提供了一个不寻常的例子，即次生代谢物通过间接抑制竞争生物的生长。
