Roy Chowdhuri Sumedha, Biswas Raha Anashuya, Mitra Souvik, Datta Jayashree, Poddar Sarkar Mousumi
Chemical Signal and Lipidomics Laboratory, Department of Botany, Centre of Advanced Study, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India.
Department of Botany, Darjeeling Government College, Lebong Cart Rd, Richmond Hill, Darjeeling, 734101, India.
Lipids. 2018 May;53(5):539-545. doi: 10.1002/lipd.12054. Epub 2018 Aug 2.
The phospholipids of two moss samples Oreoweisia laxifolia (Hookf.) Kindb. (family-Dicranaceae Schimp.) and Leptodontium viticulosoides (P. Beauv.) Wijk & Margad (family-Pottiaceae Schimp.) of the Eastern Himalayan Biodiversity Hotspot were investigated to find out any peculiarity in their fatty acid profiles. Detailed analysis of phospholipid classes and the respective fatty acids was performed using high-performance thin-layer chromatography and gas chromatography-mass spectrometry. An array of different saturated and unsaturated fatty acids were detected in both the samples. Although it has been proposed previously that acetylenic fatty acids are associated only with triacylglycerol of storage lipids, the most striking observation of the present investigation is the abundance of an acetylenic fatty acid, octadeca-6-yn-9,12,15-trienoic acid (18:4a), or Dicranin, in the phospholipids of both the mosses. The position of the triple bond in the hydrocarbon chain of the fatty acids was confirmed by dimethyloxazoline derivatization of fatty acids and their characteristic mass fragmentation pattern. The occurrence of Dicranin in phospholipids and in the Pottiaceae family is reported for the first time, with substantial explanations of the observed results. This may raise the issue of rethinking "Dicranin" as a chemotaxonomic marker of Dicranaceae.
对东喜马拉雅生物多样性热点地区的两个苔藓样本——疏松山羽藓（Oreoweisia laxifolia (Hookf.) Kindb.，曲尾藓科（Dicranaceae Schimp.））和具瘤细齿藓（Leptodontium viticulosoides (P. Beauv.) Wijk & Margad，丛藓科（Pottiaceae Schimp.））的磷脂进行了研究，以找出其脂肪酸谱中的任何独特之处。使用高效薄层色谱法和气相色谱 - 质谱联用技术对磷脂类别和相应的脂肪酸进行了详细分析。在两个样本中均检测到一系列不同的饱和脂肪酸和不饱和脂肪酸。尽管此前有人提出炔属脂肪酸仅与储存脂质的三酰甘油相关，但本研究最引人注目的发现是，在这两种苔藓的磷脂中都大量存在一种炔属脂肪酸——十八碳 - 6 - 炔 - 9,12,15 - 三烯酸（18:4a），即曲尾藓酸。通过脂肪酸的二甲基恶唑啉衍生化及其特征性的质量碎片模式，确定了脂肪酸烃链中三键的位置。首次报道了曲尾藓酸在磷脂中以及在丛藓科中的存在情况，并对观察结果进行了充分解释。这可能引发重新思考将“曲尾藓酸”作为曲尾藓科化学分类学标志物的问题。
