Alsufyani Taghreed, Engelen Aschwin H, Diekmann Onno E, Kuegler Stefan, Wichard Thomas
Friedrich Schiller University Jena, Institute for Inorganic and Analytical Chemistry, Lessingstr. 8, Jena 07743, Germany.
CCMAR, CIMAR-Laboratório Associado, Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus Gambelas, Faro 8005-139, Portugal.
Chem Phys Lipids. 2014 Oct;183:100-9. doi: 10.1016/j.chemphyslip.2014.05.008. Epub 2014 Jun 7.
Lipoxygenase/hydroperoxide lyase mediated transformations convert polyunsaturated fatty acids into various oxylipins. First, lipoxygenases catalyze fatty acid oxidation to fatty acid hydroperoxides. Subsequently, breakdown reactions result in a wide array of metabolites with multiple physiological and ecological functions. These fatty acid transformations are highly diverse in marine algae and play a crucial rule in e.g., signaling, chemical defense, and stress response often mediated through polyunsaturated aldehydes (PUAs). In this study, green tide-forming macroalgae of the genius Ulva (Chlorophyta) were collected at various sampling sites in the lagoon of the Ria Formosa (Portugal) and were surveyed for PUAs. We demonstrated that sea-lettuce like but not tube-like morphotypes produce elevated amounts of volatile C10-polyunsaturated aldehydes (2,4,7-decatrienal and 2,4-decadienal) upon tissue damage. Moreover, morphogenetic and phylogenetic analyses of the collected Ulva species revealed chemotaxonomic significance of the perspective biosynthetic pathways. The aldehydes are derived from omega-3 and omega-6 polyunsaturated fatty acids (PUFA) with 20 or 18 carbon atoms including eicosapentaenoic acid (C20:5 n-3), arachidonic acid (C20:4 n-6), stearidonic acid (C18:4 n-3), and γ-linolenic acid (C18:3 n-6). We present first evidences that lipoxygenase-mediated (11-LOX and 9-LOX) eicosanoid and octadecanoid pathways catalyze the transformation of C20- and C18-polyunsaturated fatty acids into PUAs and concomitantly into short chain hydroxylated fatty acids.
脂氧合酶/氢过氧化物裂解酶介导的转化作用将多不饱和脂肪酸转化为各种氧化脂质。首先，脂氧合酶催化脂肪酸氧化为脂肪酸氢过氧化物。随后，分解反应产生了一系列具有多种生理和生态功能的代谢产物。这些脂肪酸转化在海藻中高度多样，并在例如信号传导、化学防御和应激反应中发挥关键作用，这些反应通常由多不饱和醛（PUA）介导。在本研究中，在福尔摩沙河口泻湖（葡萄牙）的各个采样点收集了形成绿潮的石莼属（绿藻门）大型海藻，并对其PUA进行了调查。我们证明，叶片状而非管状形态型的海莴苣在组织受损时会产生大量挥发性C10 - 多不饱和醛（2,4,7 - 癸三烯醛和2,4 - 癸二烯醛）。此外，对收集到的石莼物种进行形态发生和系统发育分析，揭示了潜在生物合成途径的化学分类学意义。这些醛类源自含有20个或18个碳原子的ω-3和ω-6多不饱和脂肪酸（PUFA），包括二十碳五烯酸（C20:5 n-3）、花生四烯酸（C20:4 n-6）、硬脂酸（C18:4 n-3）和γ-亚麻酸（C18:3 n-6）。我们首次提供证据表明，脂氧合酶介导的（11-LOX和9-LOX）类二十烷酸和十八烷酸途径催化C20和C18多不饱和脂肪酸转化为PUA，并同时转化为短链羟基化脂肪酸。
