Browsing by Subject "phospholipids"

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  • Stamm, Matthias (Helsingin yliopisto, 2015)
    Microalgae (MA) are a novel feed ingredient for dairy cows. They are an alternative high quality protein source and rich in polyunsaturated fatty acids (PUFA). Supplementation of MA in dairy cow feeds has a potential to increase the amount of beneficial PUFA and bioactive molecules in milk. Four multiparous Finnish Ayrshire cows fed grass silage-based diets were used in a 4 × 4 Latin square with 21-d experimental periods to evaluate the effects of various protein supplements on fatty acid composition, oxidative stability, milk fat globule size and phospholipid content of milk. Dietary treatments consisted of 4 concentrate supplements containing soya (control), or one of three MA supplements: (i) Spirulina platensis, (ii) Chlorella vulgaris or (iii) Chlorella vulgaris + Nannochloropsis gaditana. Inclusion of MA in the diet decreased saturated fatty acid (SFA) content in milk compared to soya and tended to increase monounsaturated fatty acid and PUFA concentrations in milk. MA supplements increased 4:0, 5:0, 6:0, 17:0, 18:1 + trans-15 18:1, and 18:3n-3. Among algae, Chlorella vulgaris lead to highest contents of PUFA and 18:2n-6, Spirulina platensis to highest contents in 14:0, 16:0 and 18:3n-6 and Chlorella vulgaris + Nannochloropsis gaditana to highest contents of 6:0, 20:0 and 20:5n-3 in milk. Oxidation stability and phospholipid content of the milk were not affected by treatment. Diets containing Chlorella vulgaris led to a decrease in the number of milk fat globules, but mean globule diameter (d4,3) and milk fat globule size distribution in terms of volume were unaffected by treatment. Additionally, effects of individual animals on milk fat globule size distribution and phospholipid contents have been shown. In conclusion, MA supplementation moderately increased the content of PUFA at the expense of SFA compared to soya. Enrichment of specific fatty acids depended on the fatty acid composition of the supplement and stronger alterations of milk fatty acid composition will require higher contents of algal fatty acids. Premature spoilage through oxidation was not an issue. Finally, MA fed in the current study could only slightly alter the milk fat globule distribution, but phospholipid contents remained unchanged.
  • Liu, Dongfei; Lipponen, Katriina; Quan, Peng; Wan, Xiaocao; Zhan, Hongbo; Makilä, Ermei; Salonen, Jarno; Kostiainen, Risto; Hirvonen, Jouni; Kotiaho, Tapio; Santos, Helder A. (2018)
    By exploiting its porous structure and high loading capacity, porous silicon (PSi) is a promising biomaterial to fabricate protocells and biomimetic reactors. Here, we have evaluated the impact of physicochemical properties of PSi particles [thermally oxidized PSi, TOPSi; annealed TOPSi, AnnTOPSi; (3-aminopropyl) triethoxysilane functionalized thermally carbonized PSi, APTES-TCPSi; and thermally hydrocarbonized PSi, THCPSi] on their surface interactions with different phospholipids. All of the four phospholipids were similarly adsorbed by the surface of PSi particles, except for TOPSi. Among four PSi particles, TOPSi with hydrophilic surface and smaller pore size showed the weakest adsorption toward phosphatidylcholines. By increasing the pore size from roughly 12.5 to 18.0 nm (TOPSi vs AnnTOPSi), the quantity of phosphatidylcholines adsorbed by TOPSi was enhanced to the same level of hydrophilic APTES-TCPSi and hydrophobic THCPSi. The 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) exhibited the highest release ratio of phospholipids from all four PSi particles, and phosphatidylserine (DPPS) showed the lowest release ratio of phospholipids from PSi particles, except for TOPSi, which adsorbed less phospholipids due to the small pore size. There is consistency in the release extent of phospholipids from PSi particles and the isosteric heat of adsorption. Overall, our study demonstrates the importance of pore size and surface chemistry of PSi particles as well as the structure of phospholipids on their interactions. The obtained information can be employed to guide the selection of PSi particles and phospholipids to fabricate highly ordered structures, for example, protocells, or biomimetic reactors.
  • Sylvänne, Tuulia (Helsingfors universitet, 2013)
    Lipoproteins play a central role in the disease mechanisms of cardiovascular diseases (CVD) and therefore they have been studied widely. They carry several classes of apolipoproteins where apo-A1 and apo-B are the major classes. The sucrose based sequential lipoprotein isolation method can retrieve the lipoprotein fractions suitable for lipidomics analyses. The main lipoprotein classes are very low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and high density lipoprotein (HDL) that can be isolated easily by their density from human blood plasma or serum. Lipidomics analyses can quantify lipids that lipoproteins carry in the circulation. Mainly they carry cholesterol and its esterified forms, glycerolipids, small amounts of sphingolipids and phospholipids form their monolayer membrane. The isolation method was set-up together with scaled-down sample volumes. The protein and lipid content of the main lipoprotein fractions were evaluated by electrophoresis analysis, various enzymatic assays and lipidomics analyses. The total protein and apolipoprotein content was found to be similar as in the literature. Apo-B was found to be the main apolipoprotein in the VLDL and the LDL fractions whereas apo-A1 was the main apolipoprotein in the HDL fractions. Triglycerides (TG) were measured by enzymatic analysis and TG was mainly found in LDL and VLDL. The lipidomics analyses demonstrated the lipid content of the lipoproteins were similar as in the literature with minor changes. The main lipid class found in all the lipoproteins was cholesteryl esters (CE) followed by phosphatidylcholines (PC) that are commonly found in cell membranes. Sphingolipids such as ceramides were also detected in lipid class level only in small quantities in the lipoprotein fractions. The low initial sample volume did not correlate linearly with higher sample volume and low sample volume is not recommended to use in this specific isolation method. Based on the results of the comprehensive screening of isolated lipoproteins the isolation method was successfully established.
  • Tigistu-Sahle, Feven (Helsingfors universitet, 2012)
    In addition to being structural components of biological membranes and energy storage of cells, lipids have recently been found to participate as essential players in cell signaling, subcellular transport mechanisms, adjusting functions of integral proteins, and regulation of cell growth and apoptosis. In this study electrospray ionization mass spectrometry (ESI-MS) techniques were used to analyze the phospholipid composition of human bone marrow derived mesenchymal stem cells (BMSC). Numerous chemically distinct lipid species were quantified and the changes in their relative amounts i.e. in the cell’s lipid profile after sequential passaging were followed until senescence (usually from passage 4 up to passage 10, in some cases until p14). Subsequently, the total lipids extracted from the cell pellets were analyzed by triple quadrupole ESI-MS equipment and using lipid-class specific scanning modes. The BMSC lines studied originated from ten donors, five of which were young and five elderly individuals. In culture, the BMSC from both young and aged donors showed time-dependent changes in their phospholipid profiles. The clearest marker findings among individual lipid species were that in phosphatidylcholines (PC) and phosphatidylethanolamines (PE), the species 38:4 (acyl chain pair 18:0/20:4n-6) largely increased towards the late passages, which was seen in the BMSC derived from both the young or aged donors. Thus the reserves of 20:4n-6, the precursor of the eicosanoids having antiproliferative, apoptotic and inflammatory cellular reactions, were increased towards late passages. At phospholipid class level, lysophosphatidylcholine (LysoPC) and phosphatidylinositol (PI) totals, and the ratio of total PI to total phosphatidylserine (PI:PS) were increased from early to latest passages. The results provide new lipid biomarkers to be used for stem cell quality control. The accumulation of polyunsaturated lipid species containing 20:4n-6 or the increase of PI: PS ratio could be potential markers for cell aging and the cells’ poor viability and functionality. The results can be used to develop efficient stem cell therapies and improve patient safety.
  • Munsch-Alatossava, Patricia; Käkelä, Reijo; Ibarra, Dominique; Youbi-Idrissi, Mohammed; Alatossava, Tapani (2018)
    Cold storage aims to preserve the quality and safety of raw milk from farms to dairies; unfortunately, low temperatures also promote the growth of psychrotrophic bacteria, some of which produce heat-stable enzymes that cause spoilage of milk or dairy products. Previously, N-2 gas flushing of raw milk has demonstrated significant potential as a method to hinder bacterial growth at both laboratory and pilot plant scales. Using a mass spectrometry-based lipidomics approach, we examined the impact of cold storage [at 6 degrees C for up to 7 days, the control condition (C)], on the relative amounts of major phospholipids (phosphatidylethanolamine/PE, phosphatidylcholine/PC, phosphatidylserine/PS, phosphatidylinositol/PI, and sphingomyelin/SM) in three bovine raw milk samples, and compared it to the condition that received additional N-2 gas flushing (N). As expected, bacterial growth was hindered by the N-2-based treatment (over 4 log-units lower at day 7) compared to the non-treated control condition. At the end of the cold storage period, the control condition (C7) revealed higher hydrolysis of PC, SM, PE, and PS (the major species reached 27.2, 26.7, 34.6, and 9.9 mu M, respectively), compared to the N-2-flushed samples (N7) (the major species reached 55.6, 35.9, 54.0, and 18.8 mu M, respectively). C7 samples also exhibited a three-fold higher phosphatidic acid (PA) content (6.8 mu M) and a five-fold higher content (17.3 mu M) of lysophospholipids (LPE, LPC, LPS, and LPI) whereas both lysophospholipids and PA remained at their initial levels for 7 days in N7 samples. Taking into consideration the significant phospholipid losses in the controls, the lipid profiling results together with the microbiological data suggest a major role of phospholipase (PLase) C (PLC) in phospholipolysis during cold storage. However, the experimental data also indicate that bacterial sphingomyelinase C, together with PLases PLD and PLA contributed to the degradation of phospholipids present in raw milk as well, and potential contributions from PLB activity cannot be excluded. Altogether, this lipidomics study highlights the beneficial effects of N-2 flushing treatment on the quality and safety of raw milk through its ability to effectively hinder phospholipolysis during cold storage.