Suchergebnisse

Examines political institutions, the Constitution, local government, and regional authorities, in context of proposed reforms of the highly centralized, unitary state.

Genetic engineering can be the solution to achieve the economically feasible production of microalgal based biofuels and other bulk materials. A good number of microalgal species can grow mixotrophically using acetate as carbon source. Moreover, experimental evidence suggests that the biosynthesis of acetyl-CoA could be a limiting step in the complex multifactor-dependent biosynthesis of acylglycerides and point to acetyl-CoA synthetase (ACS) as a key enzyme in the process. In order to test this hypothesis we have engineered the model chlorophyte Chlamydomonas reinhardtii to overexpress the endogenous chloroplastic acetyl-CoA synthetase, ACS2. Expression of the ACS2 encoding gene under the control of the strong constitutive RBCS2 promoter in nitrogen-replete cultures resulted in a 2-fold increase in starch content and 60% higher acyl-CoA pool compared to the parental line. Under nitrogen deprivation, the Cr-acs2 transformant shows 6-fold higher levels of ACS2 transcript and a 2.4-fold higher accumulation of triacylglycerol (TAG) than the untransformed control. Analysis of lipid species and fatty acid profiles in the Cr-acs2 transformant revealed a higher content than the parental strain in the major glycolipids and suggests that the enhanced synthesis of triacylglycerol in the transformant is not achieved at the expense of membrane lipids, but is due to an increase in the carbon flux towards the synthesis of acetyl-CoA in the chloroplast. These data demonstrate the potential of engineering the chloroplastic ACS to increase the carbon flux towards the synthesis of fatty acids as an alternative strategy to enhance the biosynthesis of lipids in microalgae. ; Part of this work has been supported by research grants from the Spanish (AGL2016-74866-C32R-AEI/FEDER) and European (INTERREG VA POCTEP 2014-20_055 ALGARED_PLUS_5E) governments. The help of CEICAMBIO and CEIMAR University Excellence Campuses is also acknowledged. Rothamsted Research receives grant aided support from the Biotechnology and Biological Research Sciences Council (BBSRC). Haslam, Smith and Sayanova are funded under the BBSRC Institute Strategic Programme grant Tailoring Plant Metabolism (BBS/E/C/000I0420).

23 pags., 6 figs. ; Endoplasmic reticulum–plasma membrane contact sites (ER–PM CS) play fundamental roles in all eukaryotic cells. Arabidopsis thaliana mutants lacking the ER–PM protein tether synaptotagmin1 (SYT1) exhibit decreased PM integrity under multiple abiotic stresses, such as freezing, high salt, osmotic stress, and mechanical damage. Here, we show that, together with SYT1, the stress-induced SYT3 is an ER–PM tether that also functions in maintaining PM integrity. The ER–PM CS localization of SYT1 and SYT3 is dependent on PM phosphatidylinositol-4-phosphate and is regulated by abiotic stress. Lipidomic analysis revealed that cold stress increased the accumulation of diacylglycerol at the PM in a syt1/3 double mutant relative to wild-type while the levels of most glycerolipid species remain unchanged. In addition, the SYT1-green fluorescent protein fusion preferentially binds diacylglycerol in vivo with little affinity for polar glycerolipids. Our work ; This work was supported by the Ministerio de Economıa y Competitividad, co-financed by the European Regional Development Fund (grant no. BIO2017-82609-R to M.A.B.), the Ministerio de Ciencia, Innovacion y Universidades (grant no. PGC2018-098789-B-I00 to N.R.-L.) UMA-FEDER (grant UMA18-FEDERJA-154 to N.R.-L.), and the Marie SkłodowskaCurie actions (grant no. H2020-655366-IIF- PLICO to M.A.B. and N.R.-L.). N.R.L. was supported by the Ramon y Cajal program RYC-2013-12699 (MINECO, Spain). J.P.-S. and S.G.-H. were funded by the Ministerio de Economıa y Competitividad in Formacion del Personal Investigador Fellowship (grant no. BES-2012-052324) and (PRE2018- 085284), respectively. R.P.H. and J.A.N. received support from the Biotechnology and Biological Sciences Research Council (BBSRC, UK) in the form of an Institute Strategic Programme Grant (grant no. BBS/E/C/000I0420). J.L. is supported by the Program of Introducing Talents of Discipline to Universities (111 Project, grant no. B13007). A.P.M. and J.P.-S. were supported by the Shanghai Center for Plant Stress Biology (Chinese Academy of Sciences), Chinese 1000 Talents Program. A.R. was supported by the Natural Sciences and Engineering Research Council of Canada (NSERCDiscovery Grant no. RGPIN-2019-05568). Support was also provided by AEI/FEDER, UE (grant nos. BIO2016-79187-R and PID2019-106987RB-I00 to J.P.-S.) and by the European Research Council under the European Union's Seventh Framework Programme (grant no. FP7/2007-2013)/ERC grant agreement no. 742985 to J.F. and T-Rex (project number 682436 to D.V.D.).