Domoic acid (DA)-producing algal blooms are a global marine environmental issue. However, there has been no previous research addressing the question regarding the fate of DA in marine benthic environments. In this work, we investigated the DA fate in the water-sediment microcosm via the integrative analysis of a top-down metabolic model, metagenome, and metabolome. Results demonstrated that biodegradation is the leading mechanism for the nonconservative attenuation of DA. Specifically, DA degradation was prominently completed by the sediment aerobic community, with a degradation rate of 0.0681 ± 0.00954 d. The DA degradation pathway included hydration, dehydrogenation, hydrolysis, decarboxylation, automatic ring opening of hydration, and β oxidation reactions. Moreover, the reverse ecological analysis demonstrated that the microbial community transitioned from nutrient competition to metabolic cross-feeding during DA degradation, further enhancing the cooperation between DA degraders and other taxa. Finally, we reconstructed the metabolic process of microbial communities during DA degradation and confirmed that the metabolism of amino acid and organic acid drove the degradation of DA. Overall, our work not only elucidated the fate of DA in marine environments but also provided crucial insights for applying metabolic models and multi-omics to investigate the biotransformation of other contaminants.

中文翻译：

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应用代谢模型和多组学阐明沉积物中海洋藻毒素软骨藻酸（DA）的生物转化机制


产生软骨藻酸（DA）的藻华是一个全球海洋环境问题。然而，之前还没有研究解决有关 DA 在海洋底栖环境中的命运问题。在这项工作中，我们通过自上而下的代谢模型、宏基因组和代谢组的综合分析，研究了水-沉积物微观世界中的DA命运。结果表明，生物降解是 DA 非保守衰减的主要机制。具体来说，DA的降解主要由沉积物好氧群落完成，降解率为0.0681±0.00954d。 DA降解途径包括水合、脱氢、水解、脱羧、水合自动开环和β氧化反应。此外，逆向生态分析表明，微生物群落在DA降解过程中从营养竞争转变为代谢交叉取食，进一步增强了DA降解者与其他类群之间的合作。最后，我们重建了DA降解过程中微生物群落的代谢过程，并证实氨基酸和有机酸的代谢驱动了DA的降解。总的来说，我们的工作不仅阐明了 DA 在海洋环境中的命运，还为应用代谢模型和多组学研究其他污染物的生物转化提供了重要的见解。