Showing papers by "John L. Harwood published in 2019"
TL;DR: Advances in the understanding of enzymes and regulatory proteins of acyl lipid biosynthesis and turnover are described with a focus on carbon and energetic aspects and how changes in environmental factors can impact lipid metabolism are summarized.
221 citations
06 Nov 2019
TL;DR: The biosynthesis of very long chain PUFAs by algae is described and how this synthesis can be manipulated for commercial purposes, which is critical for ecosystems worldwide, as well as for human dietary lipids.
Abstract: Polyunsaturated fatty acids (PUFAs), which are divided into n-3 and n-6 classes, are essential for good health in humans and many animals. They are metabolised to lipid mediators, such as eicosanoids, resolvins and protectins. Increasing interest has been paid to the 20 or 22 carbon very long chain PUFAs, since these compounds can be used to form lipid mediators and, thus, avoid inefficient formation of dietary plant PUFAs. The ultimate sources of very long chain PUFAs are algae, which are consumed by fish and then by humans. In this review, I describe the biosynthesis of very long chain PUFAs by algae and how this synthesis can be manipulated for commercial purposes. Ultimately, the production of algal oils is critical for ecosystems worldwide, as well as for human dietary lipids.
79 citations
TL;DR: In this paper, the major stress inducible heat shock protein Hsp70 has been shown to interact with lipids beyond guarding the cellular proteome, such as protecting the cell proteome from stress, and providing a signal that can be recognized by the immune system.
60 citations
TL;DR: Novel insights are provided into the molecular mechanisms underlying the anti-atherogenic actions of DGLA and supports further assessments on its protective effects on plaque regression in vivo and in human trials.
36 citations
TL;DR: It is concluded that genes related to fatty acid and triacylglycerol biosynthesis showing dynamic expression changes may regulate the lipid distribution in embryos and seed coats of B. napus and that BnACBP2 and BNACBP6 are potentially important for oil accumulation.
Abstract: Production of vegetable oils is a vital agricultural resource and oilseed rape (Brassica napus) is the third most important oil crop globally. Although the regulation of lipid biosynthesis in oilseeds is still not fully defined, the acyl-CoA-binding proteins (ACBPs) have been reported to be involved in such metabolism, including oil accumulation, in several plant species. In this study, progressive changes in gene expression in embryos and seed coats at different stages of seed development were comprehensively investigated by transcriptomic analyses in B. napus, revealing dynamic changes in the expression of genes involved in lipid biosynthesis. We show that genes encoding BnACBP proteins show distinct changes in expression at different developmental stages of seed development and show markedly different expression between embryos and seed coats. Both isoforms of the ankyrin-repeat BnACBP2 increased during the oil accumulation period of embryo development. By contrast, the expression of the three most abundant isoforms of the small molecular mass BnACBP6 in embryos showed progressive reduction, despite having the highest overall expression level. In seed coats, BnACBP3, BnACBP4 and BnACBP5 expression remained constant during development, whereas the two major isoforms of BnACBP6 increased, contrasting with the data from embryos. We conclude that genes related to fatty acid and triacylglycerol biosynthesis showing dynamic expression changes may regulate the lipid distribution in embryos and seed coats of B. napus and that BnACBP2 and BnACBP6 are potentially important for oil accumulation.
18 citations
TL;DR: Greater LPAAT activity in seeds led to an increase in TAG content despite its low intrinsic flux control coefficient on account of the exponential nature of lipid accumulation that amplifies the effect of the small flux increment achieved by increasing its activity.
Abstract: Lysophosphatidate acyltransferase (LPAAT) catalyses the second step of the Kennedy pathway for triacylglycerol (TAG) synthesis. Here we express 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.
We estimate the flux control coefficient of LPAAT in a whole plant context by deriving a relationship between it and overall lipid accumulation, given that this is an exponential process.
Increasing LPAAT activity resulted in greater TAG accumulation in seeds of between 25 and 29%; altered fatty acid distributions in seed lipids (particularly those of the Kennedy pathway); and a redistribution of label from 14C‐glycerol between phosphoglycerides.
Greater LPAAT activity in seeds led to an increase in TAG content despite its low intrinsic flux control coefficient on account of the exponential nature of lipid accumulation that amplifies the effect of the small flux increment achieved by increasing its activity. We have also developed a novel application of metabolic control analysis likely to have broad application as it determines the in planta flux control that a single component has upon accumulation of storage products.
16 citations