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The platelet-derived growth factor (PDGF) acts by binding to its tyrosine kinase receptor, thus activating many signalling pathways leading to cellular proliferation, migration and differentiation. In this study, we were interested in the PDGF signalling pathway depending on phosphatidylinositol 3-kinase (PI3kinase), the serine/threonine kinase Akt/PKB and sterol regulatory element-binding protein (SREBP). This pathway leads to the expression of many genes coding for lipogenic enzymes including stearoyl-coenzyme A desaturase (SCD). This enzyme catalyses the Δ9-cis desaturation of saturated fatty acids, thus generating mono unsaturated fatty acids (MUFA). These are implicated in the biosynthesis of membrane phospholipids.By using two shRNA targeting SCD (shSCD) and lentiviral particles, we were capable of reducing SCD expression in human fibroblasts as well as in glioblastoma cells. First, by using a radio-labelled thymidine incorporation assay, we observed a loss of proliferative effect of PDGF on fibroblast expressing shSCD. We also observed that expression of shSCD leads to a decrease in fibroblast migration. To identify how the shSCD can cause these effects, we studied the phosphorylation of some PDGF-regulated proteins. By western blot analysis, we observed that Akt, Erk and Stat3 were phosphorylated to a lesser extent in the presence of shSCD compared to normal cells; while there was no effect for PDGFRβ, Stat5 and PLCγ1. Because of the role played by SCD in the production of MUFA which are important for cellular membrane biosynthesis, we wanted to study the effect of shSCD on membrane fluidity by using the FRAP technology. Our first results do not show any important effect. Finally, as SCD expression was shown to increase in some tumor cells, we investigated whether our shSCD can affect the proliferation of glioblastoma cells. Our results show that there is no effect of shSCD on the proliferation of these cells.To complete this study, we would like to test the localization of PDGFR in cells expressing shSCD and see if there are any differences compared to cells which do not express shSCD. The localization of PDGFR in rafts or non-rafts domains of the membrane might be important for cellular signalling. Altogether, our results suggest that SCD plays an important role in the response of human fibroblasts to PDGF Le PDGF (« Platelet-derived growth factor ») est un facteur de croissance qui agit en se liant sur un récepteur à activité tyrosine kinase permettant ainsi l’initiation de diverses voies de signalisation qui mènent à la prolifération, la migration et la différenciation cellulaire. Dans cette étude, nous nous sommes intéressés à la voie de signalisation du PDGF dépendant de la phosphatidylinositol 3-kinase (PI3kinase), de la sérine/thréonine kinase Akt/PKB et de SREBP (« Sterol regulatory element-binding protein »). Cette voie mène à l’expression de plusieurs gènes codant pour des enzymes lipogéniques telle que la stéaroyl-coenzyme A désaturase (SCD). Cette enzyme catalyse la désaturation Δ9-cis d’acides gras saturés, ce qui génère des acides gras mono-insaturés. Ceux-ci sont nécessaires entre autres pour la synthèse des phospholipides membranaires. A l’aide de deux shRNA ciblant SCD (shSCD) et par l’utilisation de lentivirus, nous sommes parvenus à réduire l’expression de SCD dans des fibroblastes humains et dans des cellules de glioblastomes. Par western blot, nous avons observé qu’en présence de shSCD, la phosphorylation de certaines protéines appartenant à la signalisation du PDGF était réduite (Akt, Erk, STAT3) ; tandis que pour d’autres protéines, il n’y avait pas changement (PDGFRβ, STAT5, PLCγ, SHP2). Grâce à un test d’incorporation de thymidine tritiée, nous avons pu mettre en évidence une perte de l’effet prolifératif du PDGF sur des fibroblastes exprimant les shSCD ; mais pas sur les cellules de glioblastomes. De plus, la migration des fibroblastes est également réduite en présence de shSCD. La protéine SCD étant impliquée dans la synthèse des acides gras insaturés qui sont présents dans la membrane plasmique, nous avons étudié l’effet des shSCD sur la fluidité membranaire par la technique du FRAP. Les premiers résultats obtenus n’ont pas montré d’effet majeur.Nous avons ainsi montré l’importance du rôle de SCD dans la signalisation, la prolifération et la migration des fibroblastes humains en réponse au PDGF

Platelet-Derived Growth Factor --- Receptors, Platelet-Derived Growth Factor --- Stearoyl-CoA Desaturase --- Humans --- Sterol Regulatory Element Binding Proteins --- Cell Membrane

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Long-chain polyunsaturated fatty acids (PUFAs) of the omega-3 family, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are physiologically important for many animals and humans. Moreover, fatty acids play an important roles in numerous contexts reflecting various levels: from their producers in natural ecosystems, microalgae, through to invertebrates and fish, and to culinary treatments of fish products for human consumption. Environmental threats such as anthropogenic pollution and its effects on PUFA yield in aquatic ecosystems as well as their transfer to terrestrial ecosystems are highlighted. Assumptions and challenges that are important for the study of PUFA in trophic webs of aquatic ecosystems as well as in human nutrition are discussed.

Research & information: general --- Biology, life sciences --- Food & society --- Fatty acid --- fish --- food web --- periphyton --- trophic transfer --- water pollution --- zoobenthos --- salmon --- pan-frying --- rosemary --- lipid oxidation --- polyunsaturated fatty acids --- aldehydes --- isoprostanes --- eicosapentaenoic acid --- docosahexaenoic acid --- nutritive quality --- eutrophication --- culinary treatments --- fatty acids --- dietary sources --- allochthonous --- Salvelinus leucomaenis --- chronic mild stress --- depression --- gut microbiota --- fish oil --- olive oil --- CLA --- conjugated linoleic acid --- ALA --- α-linolenic acid --- n-3 HUFA score --- meat fat --- vegetable fat --- mollusks --- symbiotic bacteria --- biosynthesis --- aquatic ecosystems --- subsidies --- food webs --- fatty acyl desaturase --- Δ6 - desaturase --- long-chain polyunsaturated fatty acid --- LC-PUFA --- ω3 --- ω6 --- EPA --- DHA --- AA --- essential fatty acid --- health --- transgene --- essential polyunsaturated fatty acids --- linoleic acid --- alpha-linolenic acid --- food quality --- muscle tissue --- subcutaneous adipose tissue --- liver --- green cryo-fodder --- lipids --- Leptoclinus maculatus --- ontogenesis --- adaptations --- trophic nets --- Arctic --- arctic --- Salmoniformes --- long-chain polyunsaturated fatty acids --- polar lipids --- triacylglycerols --- phytoplankton --- freshwater --- nutritional value --- Fatty acid --- fish --- food web --- periphyton --- trophic transfer --- water pollution --- zoobenthos --- salmon --- pan-frying --- rosemary --- lipid oxidation --- polyunsaturated fatty acids --- aldehydes --- isoprostanes --- eicosapentaenoic acid --- docosahexaenoic acid --- nutritive quality --- eutrophication --- culinary treatments --- fatty acids --- dietary sources --- allochthonous --- Salvelinus leucomaenis --- chronic mild stress --- depression --- gut microbiota --- fish oil --- olive oil --- CLA --- conjugated linoleic acid --- ALA --- α-linolenic acid --- n-3 HUFA score --- meat fat --- vegetable fat --- mollusks --- symbiotic bacteria --- biosynthesis --- aquatic ecosystems --- subsidies --- food webs --- fatty acyl desaturase --- Δ6 - desaturase --- long-chain polyunsaturated fatty acid --- LC-PUFA --- ω3 --- ω6 --- EPA --- DHA --- AA --- essential fatty acid --- health --- transgene --- essential polyunsaturated fatty acids --- linoleic acid --- alpha-linolenic acid --- food quality --- muscle tissue --- subcutaneous adipose tissue --- liver --- green cryo-fodder --- lipids --- Leptoclinus maculatus --- ontogenesis --- adaptations --- trophic nets --- Arctic --- arctic --- Salmoniformes --- long-chain polyunsaturated fatty acids --- polar lipids --- triacylglycerols --- phytoplankton --- freshwater --- nutritional value

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Apomixis is the consequence of a concerted mechanism that harnesses the sexual machinery and coordinates developmental steps in the ovule to produce an asexual (clonal) seed. Altered sexual developments involve widely characterized functional and anatomical changes in meiosis, gametogenesis, and embryo and endosperm formation. The ovules of apomictic plants skip meiosis and form unreduced female gametophytes whose egg cells develop into a parthenogenetic embryo, and the central cells may or may not fuse to a sperm to develop the seed endosperm. Thus, functional apomixis involves at least three components, apomeiosis, parthenogenesis, and endosperm development, modified from sexual reproduction that must be coordinated at the molecular level to progress through the developmental steps and form a clonal seed. Despite recent progress uncovering specific genes related to apomixis-like phenotypes and the formation of clonal seeds, the molecular basis and regulatorynetwork of apomixis is still unknown. This is a central problem underlying the current limitations of apomixis breeding. This book collates twelve publications addressing different topics around the molecular basis of apomixis, illustrating recent discoveries and advances toward understanding the genetic regulation of the trait, discussing the possible origins of apomixis and the remaining challenges for its commercial deployment in plants.

apomixis --- evolution --- germline --- gene regulation --- sporogenesis --- plant reproduction --- ribosome --- RNA helicase --- sexual development --- stress response --- apomeiosis --- clonal seeds --- endosperm --- heterosis capture --- molecular breeding --- parthenogenesis --- differentially expressed genes --- hybridization --- microarrays --- polyploidy --- Ranunculus --- sexuality --- character segregation --- crop biotechnology --- heterosis --- meiosis --- recombination --- agamospermy --- basal angiosperms (ANA-grade) --- sporocyteless --- polycomb-group proteins --- reproductive systems --- apomixis evolution --- APOSTART --- Poa pratensis --- diplospory --- autonomous endosperm --- genetics --- Taraxacum --- dandelion --- weeping lovegrass --- drought stress --- RNA-seq --- plant breeding --- plant development --- Hieracium piloselloides --- CRISPR/Cas9 --- PHYTOENE DESATURASE (PDS) --- amplicon sequencing --- genome editing --- tissue culture --- haploid progeny --- dicotyledon --- PsASGR-BBML --- pseudogamy --- 5-azacytidine --- abscisic acid --- apospory --- expression profiling --- fluridone --- metabolic homeostasis --- oxidative stress --- sucrose non-fermenting-related protein kinase --- n/a

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Microalgae are photosynthetic organisms with the ability to sequester and convert atmospheric carbon dioxide into high-value bioactives, and are therefore seen as a renewable and sustainable bioresource in the fields of biofuels, aquaculture and animal feeds, bioremediation of waste, nutraceuticals, pharmaceuticals, cosmeceuticals and agriculture. Moreover, algae can adjust their metabolism according to surrounding growth conditions, and this metabolic flexibility can be exploited in industrial biotechnology with genetic and metabolic engineering, when compared to other photosynthetic organisms. The metabolome is the result of the combined effects of genetic and environmental influences on metabolic processes. Metabolomic studies can provide a global view of metabolism and thereby improve our understanding of the underlying biology. Advances in metabolomic technologies have shown utility for elucidating the mechanisms which underlie fundamental biological processes, including disease pathology. This book represents research papers based around metabolomics, to improve knowledge on the metabolome and metabolism in algae, with a focus on carbon and nitrogen resource allocation. It also describes many bioanalytical techniques and emphasizes their usefulness in microalgal biotechnology. Other aspects from an ecological, biotechnological and waste-water remediation perspective are also covered.

Research & information: general --- Biology, life sciences --- Ecological science, the Biosphere --- microalgae --- cell disruption --- ultraviolet light --- biodiesel --- Chlamydomonas reinhardtii --- Dunaliella salina --- Micractinium inermum --- metabolomics --- quenching --- gas chromatography mass spectrometry (GC-MS) --- Arthrospira platensis C1 --- bioethanol --- cyanobacteria --- genome-scale metabolic model --- glycogen --- polar lipids --- Chlorella sp. --- LC-MS --- nutrient limitation --- genetic transformation --- carotenoid --- CRTI --- phytoene desaturase --- C. fritschii --- UV-B --- PAR --- time-series --- intracellular --- extracellular --- metabolites --- GC–MS --- algae --- copper --- FT-IR --- metabolite fingerprinting --- pathway analysis --- TEM --- synchronisation --- bioassay --- biomarker --- key event --- adverse outcome pathway --- Euglena --- central metabolic pathway --- subcellular location --- chromatic adaptation --- LED --- far-red light --- growth --- photosynthesis --- mass cultivation --- pigments --- Chlorogloeopsis --- microalgae --- cell disruption --- ultraviolet light --- biodiesel --- Chlamydomonas reinhardtii --- Dunaliella salina --- Micractinium inermum --- metabolomics --- quenching --- gas chromatography mass spectrometry (GC-MS) --- Arthrospira platensis C1 --- bioethanol --- cyanobacteria --- genome-scale metabolic model --- glycogen --- polar lipids --- Chlorella sp. --- LC-MS --- nutrient limitation --- genetic transformation --- carotenoid --- CRTI --- phytoene desaturase --- C. fritschii --- UV-B --- PAR --- time-series --- intracellular --- extracellular --- metabolites --- GC–MS --- algae --- copper --- FT-IR --- metabolite fingerprinting --- pathway analysis --- TEM --- synchronisation --- bioassay --- biomarker --- key event --- adverse outcome pathway --- Euglena --- central metabolic pathway --- subcellular location --- chromatic adaptation --- LED --- far-red light --- growth --- photosynthesis --- mass cultivation --- pigments --- Chlorogloeopsis

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This book contains 12 articles covering biomedicine, nutrition, and the methodology of lipidomics . These works were first published by MDPI in a Special Issue of Metabolites. Phospholipids, sphingolipids, glyosylinositolphosphoceramides, cholesteryl esters, acyl-carnitines, and oxylipins are within the lipid classes accounted for studies regarding liver disease, Wilson disease, kidney disease, cardiovascular disease, adipogenesis, and the role lipids play in cancer and virus infection. High-throughput lipid extraction and guidelines for lipid annotation are addressed in several papers. This book is expected to provide a comprehensive view of the diverse areas where lipidomics looms largest.

Research & information: general --- chronic kidney disease --- leptin --- fatty acids --- adipose tissue --- adipocytes --- adipogenesis --- differential mobility spectrometry (DMS) --- lipidomics --- lipidyzer --- mass spectrometry --- metabolomics --- phenotyping --- Simpson-Golabi-Behmel syndrome (SGBS) --- COX --- CYP450 --- LOX --- oxylipins --- PUFAs --- UPLC-MS/MS --- copper --- Wilson’s disease --- lipidomic --- liquid chromatography --- tandem mass spectrometry --- molecular network --- dry eye disease --- hyperosmolarity --- cardiovascular disease --- heart failure --- myocardial infarction --- obesity --- diabetic cardiomyopathy --- dilated cardiomyopathy --- lipids --- odd chain lipids --- lipid profiling --- Folch --- protein precipitation --- sample preparation --- relative lipid composition (Mol%) --- atopic dermatitis --- SHARPIN-deficient mice --- flow-injection mass-spectrometry --- predictive elastic net --- immunotherapy --- cancer --- biomarkers --- metabolism --- cancer cell membranes --- fatty acid biosynthesis --- essential fatty acids --- desaturase enzymes --- fatty acid signaling --- fatty acid biomarker --- sapienic acid --- sebaleic acid --- molecular nutrition --- inflammation --- drug-induced liver injury --- biomarker --- plasma lipid profiles --- ssRNA+ virus --- membrane fusion --- lipid metabolism --- cholesterol --- sphingolipids --- phosphatidylinositol --- SARS-CoV --- glycolipidomics --- GIPC --- glycosyl inositol phospho ceramides --- Lipid Data Analyzer --- ultra-high pressure liquid chromatography --- high-resolution mass spectrometry --- LC-MS --- automated annotation