Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, Novohradská 237, 379 81 Třeboň, Czech Republic.
Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, Novohradská 237, 379 81 Třeboň, Czech Republic; Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic.
Phytochemistry. 2022 Feb;194:113025. doi: 10.1016/j.phytochem.2021.113025. Epub 2021 Nov 25.
Sphingolipids are significant component of plant-cell plasma membranes, as well as algal membranes, and mediate various biological processes. One of these processes is the change in lipid content during the cell cycle. This change is key to understanding cell viability and proliferation. There are relatively few papers describing highly glycosylated glycosyl inositol phosphorylceramide (GIPC) due to problems associated with the extractability of GIPCs and their analysis, especially in algae. After alkaline hydrolysis of total lipids from the red alga Galdieria sulphuraria, GIPCs were measured by high-resolution tandem mass spectrometry and fragmentation of precursor ions in an Orbitrap mass spectrometer in order to elucidate the structures of molecular species. Fragmentation experiments such as tandem mass spectrometry in the negative ion mode were performed to determine both the ceramide group and polar head structures. Measurement of mass spectra in the negative regime was possible because the phosphate group stabilizes negative molecular ions [M-H]. ANALYSIS: of GIPCs at various stages of the cell cycle provided information on their abundance. It was found that, depending on the phases of the cell cycle, in particular during division, the uptake of all three components of GIPC, i.e., long-chain amino alcohols, fatty acids, and polar heads, changes. Structural modifications of the polar headgroup significantly increased the number of molecular species. Analysis demonstrated a convex characteristic for molecular species with only one saccharide (hexose or hexuronic acid) as the polar head. For two carbohydrates, the course of Hex-HexA was linear, while for HexA-HexA it was concave. The same was true for GIPC with three and four monosaccharides.
鞘脂是植物细胞膜以及藻类膜的重要组成部分，介导各种生物过程。其中一个过程是细胞周期中脂质含量的变化。这种变化是理解细胞活力和增殖的关键。由于与 GIPC 的提取及其分析相关的问题，描述高度糖基化的糖基肌醇磷酸神经酰胺（GIPC）的论文相对较少，尤其是在藻类中。在对红藻硫硫螺旋藻中的总脂质进行碱性水解后，通过高分辨串联质谱法和轨道阱质谱仪中前体离子的碎裂来测量 GIPC，以阐明分子物种的结构。进行了诸如负离子模式下的串联质谱等碎裂实验，以确定神经酰胺基团和极性头结构。在负模式下测量质谱是可能的，因为磷酸基团稳定了负分子离子[M-H]。对细胞周期各个阶段的 GIPC 的分析提供了有关其丰度的信息。结果发现，根据细胞周期的阶段，特别是在分裂期间，GIPC 的所有三个成分，即长链氨基醇、脂肪酸和极性头的摄取都会发生变化。极性头基团的结构修饰显着增加了分子物种的数量。分析表明，对于仅具有一个糖（己糖或己糖醛酸）作为极性头的分子物种，具有凸形特征。对于两个碳水化合物，Hex-HexA 的过程是线性的，而对于 HexA-HexA，则是凹形的。对于具有三个和四个单糖的 GIPC 也是如此。
