| 1. |
- Aslan, Selcuk, et al.
(författare)
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Wax esters of different compositions produced via engineering of leaf chloroplast metabolism in Nicotiana benthamiana
- 2014
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Ingår i: Metabolic Engineering. - : Elsevier BV. - 1096-7176 .- 1096-7184. ; 25, s. 103-112
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Tidskriftsartikel (refereegranskat)abstract
- In a future bin based economy, renewable sources for lipid compounds at attractive cost are needed for applications where today petrochemical derivatives are dominating. Wax esters and fatty alcohols provide diverse industrial uses, such as in lubricant and surfactant production. In this study, chloroplast metabolism was engineered to divert intermediates from de nova fatty acid biosynthesis to wax ester synthesis. To accomplish this, chloroplast targeted fatty acyl recluctases (EAR) and wax ester synthases (WS) were transiently expressed in Nic"onana benthamiuna loaves. Wax esters of different qualities and quantities were produced providing insights to the properties and interaction of the individual enzymes used. In particular, a phytyl ester synthase was found to be a premium candidate for medium chain wax ester synthesis. Catalytic activities of FAR and WS were also expressed as a fusion protein and determined functionally equivalent to the expression of individual enzymes for wax ester synthesis in chloroplasts. (C) 2014 The Authors. Published by Elsevier Inc. On behalf of International Metabolic Engineering Society.
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| 2. |
- Heneen, Waheeb K., et al.
(författare)
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Fusion of oil bodies in endosperm of oat grains
- 2008
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Ingår i: Planta. - : Springer Science and Business Media LLC. - 0032-0935 .- 1432-2048. ; 228:4, s. 589-599
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Tidskriftsartikel (refereegranskat)abstract
- Few microscopical studies have been made on lipid storage in oat grains, with variable results as to the extent of lipid accumulation in the starchy endosperm. Grains of medium- and high-lipid oat (Avena sativa L.) were studied at two developmental stages and at maturity, by light microscopy using different staining methods, and by scanning and transmission electron microscopy. Discrete oil bodies occurred in the aleurone layer, scutellum and embryo. In contrast, oil bodies in the starchy endosperm often had diffuse boundaries and fused with each other and with protein vacuoles during grain development, forming a continuous oil matrix between the protein and starch components. The different microscopical methods were confirmative to each other regarding the coalescence of oil bodies, a phenomenon probably correlated with the reduced amount of oil-body associated proteins in the endosperm. This was supported experimentally by SDS-PAGE separation of oil-body proteins and immunoblotting and immunolocalization with antibodies against a 16 kD oil-body protein. Much more oil-body proteins per amount of oil occurred in the embryo and scutellum than in the endosperm. Immunolocalization of 14 and 16 kD oil-body associated proteins on sectioned grains resulted in more heavy labeling of the embryo, scutellum and aleurone layer than the rest of the endosperm. Observations on the appearance of oil bodies at an early stage of development pertain to the prevailing hypotheses of oil-body biogenesis.
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| 3. |
- Heneen, Waheeb, et al.
(författare)
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The distribution of the oil in the oat grain
- 2009
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Ingår i: Plant Signaling and Behavior. - : Informa UK Limited. - 1559-2316 .- 1559-2324. ; 4, s. 55-56
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Leonova, Svetlana
(författare)
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Lipids in seeds of oat (Avena spp.), a potential oil crop : content, quality, metabolism, and possibilities for improvement
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- New oil crops with high yield and oil content are urgently needed. Oat is the only cereal that accumulates substantial amount of lipids in the endosperm. This gives it potential as an oil crop, which could address both nutritional and environmental concerns of modern society. To develop oat with increased oil content, thorough investigations on its lipid metabolism and tools for genetic manipulations are needed. Analyses of lipids in seeds of wild and cultivated oat species revealed variation in wild oat accessions in both oil content and quality. This variation should allow for development of new oat varieties for diverse applications. However, to develop oat as an oil crop, a level of 20% of the seed dry weight as oil is required and the range of oil content in the studied accessions was 4-10%. Another feature which showed almost no deviation was the amount of omega 3 fatty acid, -linolenic acid (0.6-2.1%). To develop oat varieties with ultra-high seed oil and increased content of omega 3 fatty acids, a biotechnological approach is preferred to conventional breeding methods. Lipids in oat endosperm have been reported to exist, not enclosed in oil bodies, but as non-structured oil smear. In my study, I also observed oil smears, a phenomenon probably correlated with the reduced amount of oil body associated proteins in the endosperm, as revealed by microscopic and staining methods. This was supported experimentally by SDS-PAGE separation of oil-body proteins and immunoblotting and immunolocalization with antibodies against a 16 kD oil body protein. Biochemical studies on lipid mobilization during oat seed germination demonstrated efficient utilization of oil reserves from the starchy endosperm; these results were corroborated by microscopy. An oat cultivar which is capable of accumulating high amounts of oil in the endosperm was shown to be also efficient in utilizing these reserves upon germination. Agrobacterium-mediated transformation is one of the methods for modification of oat oil content and/or its quality. The results of the analyses aimed at development of an Agrobacterium-mediated oat transformation protocol are presented in this thesis.
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| 5. |
- Leonova, Svetlana, et al.
(författare)
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Mobilization of lipid reserves during germination of oat (Avena sativa L.), a cereal rich in endosperm oil
- 2010
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Ingår i: Journal of Experimental Botany. - : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 61, s. 3089-3099
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Tidskriftsartikel (refereegranskat)abstract
- Since the cereal endosperm is a dead tissue in the mature grain, beta-oxidation is not possible there. This raises the question about the use of the endosperm oil in cereal grains during germination. In this study, mobilization of lipids in different tissues of germinating oat grains was analysed using thin-layer and gas chromatography. The data imply that the oat endosperm oil [triacylglycerol (TAG)] is not a dead-end product as it was absorbed by the scutellum, either as free fatty acids (FFAs) released from TAG or as intact TAG immediately degraded to FFAs. These data were supported by light and transmission electron microscopy (LM and TEM) studies where close contact between endosperm lipid droplets and the scutellum was observed. The appearance of the fused oil in the oat endosperm changed into oil droplets during germination in areas close to the aleurone and the scutellar epithelium. However, according to the data obtained by TEM these oil droplets are unlikely to be oil bodies surrounded by oleosins. Accumulation of FFA pools in the embryo suggested further transport of FFAs from the scutellum. Noticeably high levels of TAG were also accumulated in the embryo but were not synthesized by re-esterification from imported FFAs. Comparison between two oat cultivars with different amounts of oil and starch in the endosperm suggests that an increased oil to starch ratio in oat grains does not significantly impact the germination process.
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| 6. |
- Sunilkumar, Bindu A., et al.
(författare)
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Identification and characterization of high protein oat lines from a mutagenized oat population
- 2017
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Ingår i: Journal of Cereal Science. - : Elsevier BV. - 0733-5210. ; 75, s. 100-107
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Tidskriftsartikel (refereegranskat)abstract
- Oat is an excellent source of high-quality proteins. The protein content in cultivated oat is about 12%–15%. Oats with even higher protein contents would have great potential as a vegetative protein source. From a mutagenized oat population, 230 lines with seed protein levels of 15% or higher were identified from green house grown plants. Fifteen lines with protein levels ranging between 17 and 24% were chosen for further studies. The high protein character was confirmed by two consecutive propagations in the field. Crossings showed that the trait was stable and segregated in a Mendelian fashion. SDS-PAGE analysis revealed that the major increase was in globulin like proteins. In addition, total dietary fibre, β-glucan and lipid levels were quantified. No correlation between any of these characters and the high protein trait could be found. Thousand Kernel Weight was also monitored and shown to be stable in the high protein lines. Thus, starting from the lines presented here a further development of commercial oat varieties with protein levels of 20% or higher is feasible. Such a high protein oat would be very important to meet the consumers need for high-quality high-protein oat for the food and feed industry.
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