超高效液相色谱-四极杆-飞行时间质谱对混合光合作用糖脂的分析

采用电喷雾电离源(ESI),分别在正离子模式下对混合单半乳糖甘油二酯、双半乳糖甘油二酯和在负离子模式下对混合硫代异鼠李糖甘油二酯进行超高效液相色谱-四极杆-飞行时间质谱的定性定量研究.结果表明,采用梯度洗脱,各组分在BEH C18柱上可得到良好分离,根据各特征碎片离子可以确定糖脂的种类和酰基组成,根据特征碎片离子信号强度之间的关系,可进一步确定各酰基的位置;采用等梯度洗脱可确定各组分占总组分的百分组成,从而测定出各组分在混合脂中的绝对含量.     

小硅藻光合作用脂13 C稳定同位素定量标记分析

以小硅藻( Nitzschia closterium f. minutissima)作为研究对象,利用超高压液相色谱联用四极杆-静电场轨道阱高分辨质谱技术,研究了处于平台期的小硅藻中的光合作用脂被13 C标记的程度和速度。结果显示：在平台期13 C人工标记的10天内,所有4类光合作用脂均被13 C明显标记,其中二酰甘油双半乳糖脂( DG-DG)、磷脂酰甘油( PG)、二酰甘油硫代糖脂( SQDG)被13 C标记的总量,从刚进入平台期到平台期第8天逐渐增加,此后出现下降趋势,在第8天分别达到最大值(173±24) ng/mg,(473±41) ng/mg 及(1224±21) ng/mg,标记率分别达到56.3%,38.4%和62.6%;而二酰甘油单半乳糖脂(MGDG)被13C标记的总量在整个平台期呈现持续上升趋势,并在第10天达到(956±51) ng/mg,标记率为87.3%。可见,不同脂质在藻体内合成的先后时间有差别,为了清晰地了解生物摄食过程中对微藻中特定脂类的同化机理,需要藻体内被13 C标记的每类脂质含量的最大化,针对DGDG、PG、SQDG,应选取标记了8天的微藻来投喂生物,而针对MGDG,则应选取标记了10天的微藻投喂生物。     

Lipidomics of the Edible Brown Alga Wakame (Undaria pinnatifida) by Liquid Chromatography Coupled to Electrospray Ionization and Tandem Mass Spectrometry

The lipidome of a brown seaweed commonly known as wakame (Undaria pinnatifida), which is grown and consumed around the world, including Western countries, as a healthy nutraceutical food or supplement, was here extensively examined. The study was focused on the characterization of phospholipids (PL) and glycolipids (GL) by liquid chromatography (LC), either hydrophilic interaction LC (HILIC) or reversed-phase LC (RPLC), coupled to electrospray ionization (ESI) and mass spectrometry (MS), operated both in high and in low-resolution mode. Through the acquisition of single (MS) and tandem (MS/MS) mass spectra more than 200 PL and GL of U. pinnatifida extracts were characterized in terms of lipid class, fatty acyl (FA) chain composition (length and number of unsaturations), and regiochemistry, namely 16 SQDG, 6 SQMG, 12 DGDG, 5 DGMG, 29 PG, 8 LPG, 19 PI, 14 PA, 19 PE, 8 PE, 38 PC, and 27 LPC. The FA (C16:0) was the most abundant saturated acyl chain, whereas the monounsaturated C18:1 and the polyunsaturated C18:2 and C20:4 chains were the prevailing ones. Odd-numbered acyl chains, iJ., C15:0, C17:0, C19:0, and C19:1, were also recognized. While SQDG exhibited the longest and most unsaturated acyl chains, C18:1, C18:2, and C18:3, in the sn-1 position of glycerol, they were preferentially located in the sn-2 position in the case of PL. The developed analytical approach might pave the way to extend lipidomic investigations also for other edible marine algae, thus emphasizing their potential role as a source of bioactive lipids.     

Purification and monolayer study of the thylacoid lipids of moss marchantia polymorpha

The original lipid content of the thylakoid membranes of moss Marchantia polymorpha has been determined for the first time. In particular, the content of SQDG is almost 3 times higher than those for both of the other classes. The ratios for DGDG and MGDG are just a little bit lower than those for green algae, but almost 2 times less than those for plants. The distribution of unsaturated bonds has changed in C₁₈ -residues of fatty acids. The total content of C₁₈-residues in thylacoid lipids have been almost the same but the content of C_18:1, C_18:2 and C_18:3 are altered in the fractions of DGDG, PG and PE. The light stress produces only the quantitative, but no qualitative, changes of the thylakoid lipid composition. The properties of the thylakoid lipids and corresponding fatty acids in the monolayers at the liquid/gas interfaces have been studied. The changes in distribution of unsaturated bonds in C₁₈ residues of fatty acids at light stress have been confirmed by Langmuir method.     

Lipids from the Marine Alga <Emphasis Type="Italic">Gracilaria verrucosa</Emphasis>

The composition of lipids and fatty acids from the red alga Gracilaria verrucosa, for which a high content of 20:4n-6 acid is typical, was studied. The principal lipids were digalactosyldiacylglycerides, phosphatidylcholines (PC), monogalactosyldiacylglyderides (MGDG), and sulfoquinovosyldiacylglycerides, the fraction of each was approximately the same. Sphingophospholipids, inositephosphoceramides, were identified among the polar lipids. Each lipid class differed in the ratio of fatty acids (FA). The FA of all glycerolipids contained 20:4n-6 acid but its concentration was greatest in MGDG and PC, 67.2% and 56.5% of the acid mass.__________Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 230–232, May–June, 2005.     

A new solution for an old problem: the regiochemical distribution of the acyl chains in galactolipids can be established by electrospray ionization tandem mass spectrometry

Electrospray ionization-quadrupole ion trap mass spectrometry (ESI-QITMS), either in positive- or in negative-ion mode, has been used to establish the chemical structures (chain length, degree of unsaturation, positional distribution) of the fatty acids attached to the primary (sn-1) and secondary (sn-2) hydroxyl groups of the glycerol moiety of natural monogalactosyl- (MGDG) and digalactosyldiacylglycerols (DGDG), isolated from the freshwater dinoflagellate Glenodinium sanguineum and from a marine diatom belonging to the genus Chaetoceros. Fragmentation by collision-induced dissociation of a single component in MGDG and DGDG mixtures, separated by high-performance liquid chromatography (HPLC) and detected on-line by tandem positive-ion ESI-MS, leads to a clear-cut determination of the positional distribution of the sn-glycerol-bound fatty acyl chains. Reversed-phase liquid chromatography allowed a partial resolution of the component mixture before ESI-MS/MS analysis. These results were validated by comparison with ESI-MS data obtained for the sn-2 lysoglyceroglycolipids synthesized via regiospecific enzymatic hydrolysis of the corresponding diacylglycerols by Rhizopus arrhizus lipase.     

Marine natural products

This review covers the literature published in 2002 for marine natural products, with 579 citations (413 for the period January to December 2002) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (677 for 2002), together with their relevant biological activities, source organisms and country of origin. Syntheses that lead to the revision of structures or stereochemistries have been included (114), including any first total syntheses of a marine natural product.     

Marine natural products

This review covers the literature published in 2004 for marine natural products, with 693 citations (491 for the period January to December 2004) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (716 for 2004), together with their relevant biological activities, source organisms and country of origin. Biosynthetic studies (8), and syntheses (80), including those that lead to the revision of structures or stereochemistries, have been included.     

Marine natural products

This review covers the literature published in 2001 for marine natural products, with 497 citations (373 for the period January to December 2001) and includes 793 compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds and new stereochemical assignments (683 for 2001), together with relevant biological activities, source organisms and country of origin. Syntheses that confirm or revise structures or stereochemistries have been included (95), including any first total synthesis of a marine natural product.     

Marine natural products

This review covers the literature published in 2003 for marine natural products, with 619 citations (413 for the period January to December 2003) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (656 for 2003), together with their relevant biological activities, source organisms and country or origin. Biosynthetic studies or syntheses that lead to the revision of structures or stereochemistries have been included (78), including any first total syntheses of a marine natural product.     

Marine natural products

This review covers the literature published in 2005 for marine natural products, with 704 citations (493 for the period January to December 2005) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (812 for 2005), together with their relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.     

Marine natural products

This review covers the literature published in 2006 for marine natural products, with 758 citations (534 for the period January to December 2006) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, cnidaria, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (779 for 2006), together with their relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.     

Marine natural products

This review covers the marine natural products literature for the year 2000 and is organized phylogenetically, with sections on marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates. echinoderms and miscellaneous marine organisms. There is an emphasis on new structures, stressing their biological activities, source organisms and countries of origin, and also syntheses that confirm the structures of known compounds. The review contains 869 structures and 592 references, of which 434 appeared between January and December 2000.     

Natural depuration rate and concentration of cesium-137 radionuclide in Black Sea macro algae

Cesium-137 concentrations in red, brown and green algae have been studied for the calculation of natural depuration rates. The algae species were collected from the same population of the Black Sea stations during the period of 1986–1995. The natural depuration rates are estimated as biological half-lives. The pattern of depuration results represented by a single component for each algae division. The biological half-lives of¹³⁷Cs in red (Phyllophora nervosa), green (Chaetomorpha linum) and brown (Cystoceira barbata) algae are estimated to be 18.5, 21.6 and 29.3 months, respectively.¹³⁷Cs and⁴⁰K activity levels and their ratios in algae species in two stations in Black Sea region of Turkey have been determined during the period of 1990–1995. The results showed that the Sinop region was more contaminated than the ile region on the Black Sea coast of Turkey from the Chernobyl accident.     

Marine natural products

Covering: 2010. Previous review: Nat. Prod. Rep., 2011, 28, 196. This review covers the literature published in 2010 for marine natural products, with 895 citations (590 for the period January to December 2010) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1003 for 2010), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.     

Determination of elements in algae by different atomic spectroscopic methods

The chemistry of substances derived from plants has received a great deal of attention in the last several decades. Today, natural products and their synthetic analogs also play an important role in the pharmaceutical and food industry. Several interesting reviews on algae were published in the last 10 years. Algae, especially the red algae, are very helpful in every day practice in many fields, e.g. algal polysaccharides, agar, carrageenan and some algae extracts are used in agricultural, medicines and in food products, respectively (The Constituents of Red Algae, 1999; Gelling Hydrocolloids in Food Products Applications, 1979, p. 186; Marine Natural Products Chemistry, 1997, p. 337; Algae Polysaccharides, 1983, p. 195). The biological and pharmaceutical properties promote interest among chemists to focus their attention on algae, as yet, a wide open field (Synthesis and Proceedings of the Second EUMAC Workshop, Marine Eutrophication and Bentic Macrophytes, p. 2). The most extensively studied algal phyla are Chlorophyceae (green algae) (J. Phycol. 26 (1990) 670), Rhodophyceae (red algae) (J. Phycol. 25 (1989) 522) and Phaeophyceae (brown algae) (J. Phycol. 31 (1995) 325; J. Phycol. 32 (1996) 614). Concentrations of four elements (Ca, Mg, K, Na) were determined in the above-mentioned algal phyla by different atomic spectroscopic methods (F-AES, ICP-AES) after the digestion of algal samples with cc. HNO₃ in a microwave apparatus. Not only the Ca and Mg contents, but the ratio of the calcium to magnesium was calculated in every case. This ratio was lower (0.5–0.8) in green algae than in the red and brown algae (1.3–14.4). Therefore, the green algae are better magnesium sources than the red and brown. The elemental composition is of great importance in the ion system of human organism. It is usually characterized by the ion quotient ([Ca²⁺]+[Na⁺]:[Mg²⁺]+[K⁺]), which is approximately 1.0 under ideal conditions. However, in the human body this mole ratio generally varies between 2.5 and 4.0. The ion quotient was calculated by averaging between 1 and 2 in different algal phyla. This means that the 2.5–4.0 mole ratio can be decreased by different algal foods in the human organism.     

Structure and orientation of puroindolines into wheat galactolipid monolayers

Puroindolines (PINs), basic and cysteine-rich proteins of wheat endosperm, are composed of two proteins, puroindoline-a (PIN-a) and puroindoline-b (PIN-b). Using a monolayer assay at the air/liquid interface, both PIN-a and PIN-b were studied in pure components and mixed with wheat galactolipids, 1,2-di-O-acyl-3-O-(beta-d-galactopyranosyl)- sn-glycerol (MGDG) and 2-di-O-acyl-3-O-(beta-d-galactopyranosyl-1,6-beta-d-galactopyranosyl)-sn-glycerol (DGDG). Following the adsorption of PINs at the air/liquid interface thanks to surface pressure increases, we concluded that PIN-a displays a more amphipathic character than PIN-b. Compression isotherms combined with ellipsometric measurements showed that the area per molecule is smaller and the protein film is more condensed for PIN-a than for PIN-b. According to the polarization modulation-infrared reflection-absorption spectroscopy data, both proteins display a highly alpha-helical structure and the alpha-helices are oriented rather parallel to the interface. By measuring the overpressure due to PIN adsorption into MGDG and DGDG monolayers, we observed that PIN-a interacts more strongly into lipid films than PIN-b. The observation by atomic force microscopy of mixed protein/lipid films showed that the nature of the lipid plays a significant role in the organization of PINs, particularly for PIN-a. The presence of galactolipids at the interface stabilizes the alpha-helical structure of PINs, but significant changes were observed concerning the orientation of the alpha-helices. They adopt a perfect parallel orientation to the interface in the MGDG monolayer, whereas the bundle of alpha-helices orients normal to the interface in the DGDG film.     

Marine macroalgae analyzed by mass spectrometry are rich sources of polyunsaturated fatty acids

Algae from cold water (Canada) and warm water (China) were analyzed for their total lipid content, and for their fatty acid (FA) composition and content. The major findings are that FA from Canadian algae are generally richer in polyunsaturated FA (PUFA), with a higher n-3/n-6 FA ratio, and a higher degree of total unsaturation. The 18 C, 4 double bonds FA (18 : 4 stearidonic acid, morotic acid as synonym) was detected in greater amounts in cold water samples. The high levels of total PUFA, and especially of n-3 FA in Canadian algae, suggests their possible utilizations for nutritional purposes.     

石莼吸附脱色处理水溶性染料

本文以大型海藻石莼作吸附剂，对结晶紫等7种不同结构的水溶性染料分子的单水溶液和模拟混合染料废水进行吸附脱色研究，探讨了吸附剂的性能和影响吸附脱色效果的有关因素。结果表明，石莼对大多数水溶性染料具有良好的吸附脱色效果，而且COD去除率高，在染料废水处理中应用前景广阔。