Biosynthesis of fatty acids and triacylglycerols by 2,6 ..

Presentation Summary : Lots of lipid biosynthesis in liver, ... join them to glycerol to make triacylglycerol Reverse of b-oxidation, but enzymes and control are different b-oxidation ...

The regulation of triacylglycerol biosynthesis in cocoa ..

 It’s your single place to instantly discover and read the research  that matters to you.

by hydrolysis of triacylglycerols

The gene sequence of PAP2 listed in the JGI database (JGI Protein ID: 343983) was used for the design of primers for the amplification of the gene. A full-length CrPAP2 gene was amplified by PCR. A DNA fragment of about 1 000 bp was inserted into the pMD-18T vector and sequenced. Compared with the 343983 sequence in the JGI C. reinhardtii v4.0 database, the cloned CrPAP2 CDS had a sequence with 978 bp and showed 100% consistency. This cloned fragment was named CrPAP2.

processing one acetate unit at a time

The method of Ullah et al. () was used to measure the CrPAP2 activities. The amount of Pi in nmoles released by PAP from the substrate dioleoyl-phosphatidate (1,2-dioleoyl-sn-glycero-3-phosphate, sodium salt) was determined. The reaction was stopped by the addition of 2 ml AMA reagent (acetone: 10 mmol/L ammonium molybdate:5 mol/L sulfuric acid mixture, 2:1:1 (v/v/v)), followed by 100 ml of 1 mol/L citrate solution. The resulting turbidity was removed using centrifugation at 12 000×g for 6 min at room temperature. The absorbance of the resulting yellow color was read at 355 nm using a spectrophotometer. The enzyme unit, kat, was defined as the moles of the substrate converted per second (Heinonen and Lahti, ; Ullah et al., ).

It’s your single place to instantly discover and read the research  that matters to you.
Correlation between lipid concentration (triolein mg/20 ml) and the fluorescence value FD470/570

Long Chain (C20 and C22) Fatty Acid Biosynthesis in ..

AB - Microalgae are emerging as suitable feedstocks for renewable biofuel production. Characterizing the metabolic pathways involved in the biosynthesis of energy-rich compounds, such as lipids and carbohydrates, and the environmental factors influencing their accumulation is necessary to realize the full potential of these organisms as energy resources. The model green alga Chlamydomonas reinhardtii accumulates significant amounts of triacylglycerols (TAGs) under nitrogen starvation or salt stress in medium containing acetate. However, since cultivation of microalgae for biofuel production may need to rely on sunlight as the main source of energy for biomass synthesis, metabolic and gene expression changes occurring in Chlamydomonas and Coccomyxa subjected to nitrogen deprivation were examined under strictly photoautotrophic conditions. Interestingly, nutrient depletion triggered a similar pattern of early synthesis of starch followed by substantial TAG accumulation in both of these fairly divergent green microalgae. A marked decrease in chlorophyll and protein contents was also observed, including reduction in ribosomal polypeptides and some key enzymes for CO 2 assimilation like ribulose-1,5-bisphosphate carboxylase/oxygenase. These results suggest that turnover of nitrogen-rich compounds such as proteins may provide carbon/energy for TAG biosynthesis in the nutrient deprived cells. In Chlamydomonas, several genes coding for diacylglycerol:acyl-CoA acyltransferases, catalyzing the acylation of diacylglycerol to TAG, displayed increased transcript abundance under nitrogen depletion but, counterintuitively, genes encoding enzymes for de novo fatty acid synthesis, such as 3-ketoacyl-ACP synthase I, were down-regulated. Understanding the interdependence of these anabolic and catabolic processes and their regulation may allow the engineering of algal strains with improved capacity to convert their biomass into useful biofuel precursors.

Biosynthesis of sex pheromone components and glycerolipid precursors from ..

major steps in the biosynthesis of cholesterol from acetate, ..

Information on the Chlamydomonas PAP2 gene (JGI Protein ID: 343983) was obtained from the JGI Chlamydomonas database. A transmembrane assay was conducted using TMHMM 2.0. Euk-mPLoc 2.0 was used to predict the subcellular localization of proteins (Chou and Shen, ; ; ; ; Chou et al., ; ; Wu et al., ; Chou, ). Sequence alignment and the phylogenetic tree of the PAP2 were created using MEGA version 4.1 (Tamura et al., ). Active consensus sites were identified based on the Sanger Pfam database ().

Biosynthesis of fatty acids and triacylglycerols by 2,6,10,14-tetramethyl ..

Isoprenoid compounds are synthesized from a common intermediate, ..

Lipid biosynthesis is essential for eukaryotic cells, but the mechanisms of the process in microalgae remain poorly understood. Phosphatidic acid phosphohydrolase or 3-sn-phosphatidate phosphohydrolase (PAP) catalyzes the dephosphorylation of phosphatidic acid to form diacylglycerols and inorganic orthophosphates. This reaction is integral in the synthesis of triacylglycerols. In this study, the mRNA level of the PAP isoform CrPAP2 in a species of Chlamydomonas was found to increase in nitrogen-free conditions. Silencing of the CrPAP2 gene using RNA interference resulted in the decline of lipid content by 2.4%–17.4%. By contrast, over-expression of the CrPAP2 gene resulted in an increase in lipid content by 7.5%–21.8%. These observations indicate that regulation of the CrPAP2 gene can control the lipid content of the algal cells. In vitro CrPAP2 enzyme activity assay indicated that the cloned CrPAP2 gene exhibited biological activities.