Overexpression of phospholipid: diacylglycerol acyltransferase in Brassica napus results in changes in lipid metabolism and oil accumulation.

The regulation of lipid metabolism in oil seeds is still not fully understood and increasing our knowledge in this regard is of great economic, as well as intellectual, importance. Oilseed rape (Brassica napus) is a major global oil crop where increases in triacylglycerol (TAG) accumulation have been achieved by overexpression of relevant biosynthetic enzymes. In this study, we expressed Arabidopsis phospholipid: diacylglycerol acyltransferase (PDAT1), one of the two major TAG-forming plant enzymes in B.

Increase in lysophosphatidate acyltransferase activity in oilseed rape (Brassica napus) increases seed triacylglycerol content despite its low intrinsic flux control coefficient.

Lysophosphatidate acyltransferase (LPAAT) catalyses the second step of the Kennedy pathway for triacylglycerol (TAG) synthesis. In this study we expressed Trapaeolum majus LPAAT in Brassica napus (B. napus) cv 12075 to evaluate the effects on lipid synthesis and estimate the flux control coefficient for LPAAT.

Metabolic control analysis of developing oilseed rape (Brassica napus cv Westar) embryos shows that lipid assembly exerts significant control over oil accumulation.

Metabolic control analysis allows the study of metabolic regulation. We applied both single- and double-manipulation top-down control analysis to examine the control of lipid accumulation in developing oilseed rape (Brassica napus) embryos. The biosynthetic pathway was conceptually divided into two blocks of reactions (fatty acid biosynthesis (Block A), lipid assembly (Block B)) connected by a single system intermediate, the acyl-coenzyme A (acyl-CoA) pool.

Antisense expression of 3-oxoacyl-ACP reductase affects whole plant productivity and causes collateral changes in activity of fatty acid synthase components.

Brassica napus cv Westar plants were transformed with 3-oxoacyl-ACP reductase (KR) in antisense orientation, driven by either the cauliflower mosaic virus 35S promoter or a seed-specific acyl carrier protein promoter to determine the effects on plant productivity and on the activity of other fatty acid synthase (FAS) components. In plants with altered KR activity, total seed yield was reduced in all cases. In less severely affected plant lines, seeds had a normal appearance and composition but the yield of seeds was reduced by approximately 50%.

Tandem affinity purification tagging of fatty acid biosynthetic enzymes in Synechocystis sp. PCC6803 and Arabidopsis thaliana.

De novo fatty acid synthesis in plants occurs primarily in the plastids and is catalysed by a type-II fatty acid synthase (FAS) in which separate enzymes catalyse sequential reactions. Genes encoding all of the plant FAS components have been identified, following enzyme purification or by homology to Escherichia coli genes, and the structure of a number of the individual proteins determined. There are several lines of biochemical evidence indicating that FAS enzymes form a multi-protein complex and both in vitro and in vivo strategies can be used to investigate the association and interactions between them.

Beta-lactam resistance in Staphylococcus aureus cells that do not require a cell wall for integrity.

Staphylococcus aureus ATCC 9144 cells with defective cell walls were generated on a medium with elevated osmolality in the presence of sublethal levels of penicillin G. On removal of antibiotic pressure, the cells exhibited stable penicillin and methicillin resistance. The resistance was homogeneous and its acquisition was enhanced following transient cell wall-defective growth.

Squash glycerol-3-phosphate (1)-acyltransferase. Alteration of substrate selectivity and identification of arginine and lysine residues important in catalytic activity.

Glycerol-3-phosphate 1-acyltransferase is a soluble chloroplast enzyme involved in glycerol-lipid biosynthesis associated with chilling resistance in plants (). Resistance is associated with higher selectivity for unsaturated acyl substrates over saturated ones. In vitro substrate selectivity assays performed under physiologically relevant conditions have been established that discriminate between selective and non-selective forms of the enzyme.

Fatty acid and lipid biosynthetic genes are expressed at constant molar ratios but different absolute levels during embryogenesis.

In plants, fatty acid and complex lipid synthesis requires the correct spatial and temporal activity of many gene products. Quantitative northern analysis showed that mRNA for the biotin carboxylase subunit of heteromeric acetyl-coenzyme A carboxylase, fatty acid synthase components (3-oxoacyl-acyl carrier protein [ACP] reductase, enoyl-ACP reductase, and acyl-ACP thioesterase), and stearoyl-ACP desaturase accumulate in a coordinate manner during Brassica napus embryogenesis. The mRNAs were present in a constant molar stoichiometric ratio.

Kinetic mechanism and order of substrate binding for sn-glycerol-3-phosphate acyltransferase from squash (Cucurbita moschata).

sn-Glycerol-3-phosphate acyltransferase (G3PAT, EC 2.3.1.