by Staff Writers
Tokyo, Japan (SPX) Mar 01, 2017
In the modern society, energy generation heavily relies on fossil fuels, which, however, lead to environmental pollution and depletion of non-renewable resources. Photosynthetic organisms such as plants and green algae can transform atmospheric carbon dioxide into carbon storage molecules, especially oils such as triacylglycerols (TAGs), which can be used as biofuels. In this context, microalgae provide advantages of high oil content and growth in extreme environments, including high salinity, temperature, or pH.
Nannochloropsis is a genus of microalgae which can accumulate TAGs up to 50% of dry weight; however, the mechanisms underlying their oleaginous trait are largely unknown.
Scientists from Tokyo Institute of Technology lead by Professor Hiroyuki Ohta have addressed this problem by investigating lipid metabolism in Nannochloropsis oceanica. TAGs are synthesized in the extraplastidic Kennedy pathway through sequential addition of three fatty acyl moieties to the glycerol backbone. Among the participating enzymes, the scientists focused on four lysophosphatidic acid acyltransferases (LPATs 1-4) responsible for the addition of fatty acids at position 2.
They found that phylogenetically, LPAT1 and LPAT2 belong to different subfamilies, while LPAT3 and LPAT4 have a close evolutionary relationship. Accordingly, these enzymes appeared to have distinct functional activities as revealed by using mutant strains of N. oceanica lacking either one or two of the four LPATs. Thus, LPAT1 was found to mainly participate in the synthesis of membrane lipids, while LPAT4 was responsible for TAG biosynthesis, and LPAT2 and LPAT3 contributed to both processes.
LPATs were labeled with fluorescent tags and their intracellular location was examined using confocal microscopy. While LPAT1 and LPAT2 showed a typical ER localization pattern, LPAT3 and LPAT4 were observed specifically at the perimeter of lipid droplets (LDs) (Figure 2), which was likely due to the presence of long (30-40 residues) hydrophobic domains in their structures that enable anchoring to the LD surface.
Based on their results, the scientists suggest that for LD formation, LPAT2 is mainly involved in the initial TAG synthesis in the ER, and LPAT3 and LPAT4 localize on LD surface in the periphery and contribute to further growth of LDs.
Thus, the study of Professor Ohta and his colleagues provide direct evidence that the oleaginous trait of Nannochloropsis is supported by LPATs in the perimeter of LDs.
Ithaca NY (SPX) Feb 28, 2017
When Geoffrey Coates, a professor of chemistry and chemical biology at Cornell University, gives a talk about plastics and recycling, he usually opens with this question: What percentage of the 78 million tons of plastic used for packaging - for example, a 2-liter bottle or a take-out food container - actually gets recycled and re-used in a similar way? The answer, just 2 percent. Sadly, n ... read more
Tokyo Institute of Technology
Bio Fuel Technology and Application News
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|