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The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform

D J King – 1st expert on this subject based on the ideXlab platform

  • trans fatty acids in human milk are inversely associated with concentrations of essential all cis n 6 and n 3 fatty acids and determine trans but not n 6 and n 3 fatty acids in plasma lipids of breast fed infants
    The American Journal of Clinical Nutrition, 1999
    Co-Authors: Sheila M Innis, D J King


    Background: Human milk fatty acids vary with maternal dietary fat composition. Hydrogenated dietary oils with trans fatty acids may displace cis n-6 and n-3 unsaturated fatty acids or have adverse effects on their metabolism. The effects of milk trans, n-6, and n-3 fatty acids in breast-fed infants are unclear, although n-6 and n-3 fatty acids are important in infant growth and development. Objective: We sought to determine the relations between trans and cis unsaturated fatty acids in milk and plasma phospholipids and triacylglycerols of breast-fed infants, and to identify the major maternal dietary sources of trans fatty acids. Design: We collected milk from 103 mothers with exclusively breast-fed 2-mo-old infants, blood from 62 infants, and 3-d dietary records from 21 mothers. Results: Mean (±SEM) percentages of trans fatty acids were as follows: milk, 7.1 ± 0.32%; infants’ triacylglycerols, 6.5 ± 0.33%; and infants’ phospholipids, 3.7 ± 0.16%. Milk trans fatty acids, α-linolenic acid (18:3n-3), arachidonic acid (20:4n-6), docosahexaenoic acid (22:6n-3) (P <0.001), and linoleic acid (18:2n-6) (P = 0.007) were each related to the same fatty acid in infant plasma phospholipids. Milk trans fatty acids were inversely related to milk 18:2n-6 and 18:3n-3, but not to milk or infant plasma 20:4n-6 or 22:6n-3. trans Fatty acids represented 7.7% of maternal total fat intake (2.5% of total energy); the major dietary sources were bakery products and breads (32%), snacks (14%), fast foods (11%), and margarines and shortenings (11%). Conclusions: There were comparable concentrations of trans fatty acids in the maternal diet, breast milk, and plasma triacylglycerols of breast-fed infants. Prepared foods were the major dietary source of trans fatty acids.

Vladimir Shulaev – 2nd expert on this subject based on the ideXlab platform

  • sensitive and rapid method for amino acid quantitation in malaria biological samples using accq tag ultra performance liquid chromatography electrospray ionization ms ms with multiple reaction monitoring
    Analytical Chemistry, 2010
    Co-Authors: Jenny M Armenta, Vladimir Shulaev, Diego F Cortes, John M Pisciotta, Joel L Shuman, Kenneth W Blakeslee, Dominique Rasoloson, Oluwatosin Ogunbiyi, David J Sullivan


    An AccQ•Tag ultra performance liquid chromatography−electrospray ionization−tandem mass spectrometry (AccQ•Tag-UPLC-ESI-MS/MS) method for fast, reproducible, and sensitive amino acid quantitation in biological samples, particularly, the malaria parasite Plasmodium falciparum is presented. The Waters Acquity TQD UPLC/MS system equipped with a photodiode array (PDA) detector was used for amino acid separation and detection. The method was developed and validated using amino acid standard mixtures containing acidic, neutral, and basic amino acids. For MS analysis, the optimum cone voltage implemented, based on direct infusion analysis of a few selected AccQ•Tag amino acids with multiple reaction monitoring, varied from 29 to 39 V, whereas the collision energy varied from 15 to 35 V. Calibration curves were built using both internal and external standardization. Typically, a linear response for all amino acids was observed at concentration ranges of 3 × 10−3-25 pmol/μL. For some amino acids, concentration lim…

Jay D Keasling – 3rd expert on this subject based on the ideXlab platform

  • metabolic engineering of saccharomyces cerevisiae for production of fatty acid derived biofuels and chemicals
    Metabolic Engineering, 2014
    Co-Authors: Weerawat Runguphan, Jay D Keasling


    As the serious effects of global climate change become apparent and access to fossil fuels becomes more limited, metabolic engineers and synthetic biologists are looking towards greener sources for transportation fuels. In recent years, microbial production of high-energy fuels by economically efficient bioprocesses has emerged as an attractive alternative to the traditional production of transportation fuels. Here, we engineered the budding yeast Saccharomyces cerevisiae to produce fatty acid-derived biofuels and chemicals from simple sugars. Specifically, we overexpressed all three fatty acid biosynthesis genes, namely acetyl-CoA carboxylase (ACC1), fatty acid synthase 1 (FAS1) and fatty acid synthase 2 (FAS2), in S. cerevisiae. When coupled to triacylglycerol (TAG) production, the engineered strain accumulated lipid to more than 17% of its dry cell weight, a four-fold improvement over the control strain. Understanding that TAG cannot be used directly as fuels, we also engineered S. cerevisiae to produce drop-in fuels and chemicals. Altering the terminal “converting enzyme” in the engineered strain led to the production of free fatty acids at a titer of approximately 400 mg/L, fatty alcohols at approximately 100 mg/L and fatty acid ethyl esters (biodiesel) at approximately 5 mg/L directly from simple sugars. We envision that our approach will provide a scalable, controllable and economic route to this important class of chemicals.