Imbs Andrey B, Yakovleva Irina M, Dautova Tatiana N, Bui Long H, Jones Paul
A.V. Zhirmunsky Institute of Marine Biology, Far-Eastern Branch of Russian Academy of Sciences, 690041 Vladivostok, Russian Federation.
A.V. Zhirmunsky Institute of Marine Biology, Far-Eastern Branch of Russian Academy of Sciences, 690041 Vladivostok, Russian Federation.
Phytochemistry. 2014 May;101:76-82. doi: 10.1016/j.phytochem.2014.02.012. Epub 2014 Mar 4.
High diversity of fatty acid (FA) composition of endosymbiotic dinoflagellates of the Symbiodinium group (zooxanthellae) isolated from different cnidarian groups has been found. To explain this diversity, FA composition of the total lipids of pure symbiont fractions (SF) and host cell tissue fractions (HF) isolated from one hydrocoral, two soft coral, and seven hard coral species inhabiting the shallow waters of the South China Sea (Vietnam) were compared. Symbiodinium phylogenetic clade designation for each SF was also determined, however, the relationship between the clade designation and FA composition of Symbiodinium was not found. The profiles of marker polyunsaturated FAs (PUFAs) of symbionts (18:4n-3, 18:5n-3, 20:5n-3) did not depend on taxonomic designation of the host and reflected only a specimen-specific diversity of the SF lipids. Several FAs such as 20:0, C24 PUFAs, 22:5n-6, and 18:2n-7 concentrated in HF lipids but were also found in SF lipids. For ten cnidarian species studied, the principal components analysis of total FAs (27 variables) of the symbiotic fractions was performed. The clear division of the symbiotic dinoflagellates according to the host systematic identity was found on a subclass level. This division was mainly caused by the FAs specific for the host lipids of each cnidarian subclasses such as hard corals, soft corals, and hydrocorals. Thus, the coral hosts affect the FA profile of their symbionts and cause the diversity of FA composition of Symbiodinium. The transfer of FAs from the coral host to their symbiotic dinoflagellates and modulation of PUFA biosynthesis in symbionts by the host are considered as possible reasons of the diversity studied.
研究发现，从不同刺胞动物群体中分离出的共生甲藻（虫黄藻）内共生体的脂肪酸（FA）组成具有高度多样性。为了解释这种多样性，对从生活在南海（越南）浅水区的一种水螅珊瑚、两种软珊瑚和七种硬珊瑚物种中分离出的纯共生体组分（SF）和宿主细胞组织组分（HF）的总脂质中的FA组成进行了比较。还确定了每个SF的共生甲藻系统发育分支名称，然而，未发现分支名称与共生甲藻FA组成之间的关系。共生体的标志性多不饱和脂肪酸（PUFA）（18:4n-3、18:5n-3、20:5n-3）的谱图不依赖于宿主的分类名称，仅反映了SF脂质的标本特异性多样性。几种脂肪酸，如20:0、C24 PUFA、22:5n-6和18:2n-7集中在HF脂质中，但也存在于SF脂质中。对于所研究的十种刺胞动物物种，对共生组分的总脂肪酸（27个变量）进行了主成分分析。在亚纲水平上发现了根据宿主系统身份对共生甲藻进行的明确划分。这种划分主要是由每个刺胞动物亚纲（如硬珊瑚、软珊瑚和水螅珊瑚）宿主脂质特有的脂肪酸引起的。因此，珊瑚宿主会影响其共生体的FA谱图，并导致共生甲藻FA组成的多样性。脂肪酸从珊瑚宿主转移到其共生甲藻以及宿主对共生体中PUFA生物合成的调节被认为是所研究多样性的可能原因。
