| 1. |
- Aslan, Selcuk, et al.
(författare)
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Increased production of wax esters in transgenic tobacco plants by expression of a fatty acid reductase:wax synthase gene fusion
- 2015
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Ingår i: Transgenic Research. - : Springer Science and Business Media LLC. - 0962-8819 .- 1573-9368. ; 24, s. 945-953
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Tidskriftsartikel (refereegranskat)abstract
- Wax esters are hydrophobic lipids consisting of a fatty acid moiety linked to a fatty alcohol with an ester bond. Plant-derived wax esters are today of particular concern for their potential as cost-effective and sustainable sources of lubricants. However, this aspect is hampered by the fact that the level of wax esters in plants generally is too low to allow commercial exploitation. To investigate whether wax ester biosynthesis can be increased in plants using transgenic approaches, we have here exploited a fusion between two bacterial genes together encoding a single wax ester-forming enzyme, and targeted the resulting protein to chloroplasts in stably transformed tobacco (Nicotiana benthamiana) plants. Compared to wild-type controls, transgenic plants showed both in leaves and stems a significant increase in the total level of wax esters, being eight-fold at the whole plant level. The profiles of fatty acid methyl ester and fatty alcohol in wax esters were related, and C16 and C18 molecules constituted predominant forms. Strong transformants displayed certain developmental aberrations, such as stunted growth and chlorotic leaves and stems. These negative effects were associated with an accumulation of fatty alcohols, suggesting that an adequate balance between formation and esterification of fatty alcohols is crucial for a high wax ester production. The results show that wax ester engineering in transgenic plants is feasible, and suggest that higher yields may become achieved in the near future.
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| 2. |
- Aslan, Selcuk, et al.
(författare)
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Transient silencing of the KASII genes is feasible in Nicotiana benthamiana for metabolic engineering of wax ester composition
- 2015
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- The beta-ketoacyl-ACP synthase II (KASII) is an enzyme in fatty acid biosynthesis, catalyzing the elongation of 16:0-acyl carrier protein (ACP) to 18:0-ACP in plastids. Mutations in KASII genes in higher plants can lead to lethality, which makes it difficult to utilize the gene for lipid metabolic engineering. We demonstrated previously that transient expression of plastid-directed fatty acyl reductases and wax ester synthases could result in different compositions of wax esters. We hypothesized that changing the ratio between C16 (palmitoyl-compounds) and C18 (stearoyl-compounds) in the plastidic acyl-ACP pool by inhibition of KASII expression would change the yield and composition of wax esters via substrate preference of the introduced enzymes. Here, we report that transient inhibition of KASII expression by three different RNAi constructs in leaves of N. benthamiana results in almost complete inhibition of KASII expression. The transient RNAi approach led to a shift of carbon flux from a pool of C18 fatty acids to C16, which significantly increased wax ester production in AtFAR6-containing combinations. The results demonstrate that transient inhibition of KASII in vegetative tissues of higher plants enables metabolic studies towards industrial production of lipids such as wax esters with specific quality and composition.
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| 3. |
- Jin, Y. K., et al.
(författare)
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A Dual-Promoter Gene Orchestrates the Sucrose-Coordinated Synthesis of Starch and Fructan in Barley
- 2017
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Ingår i: Molecular Plant. - : Elsevier BV. - 1674-2052 .- 1752-9867. ; 10:12, s. 1556-1570
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Tidskriftsartikel (refereegranskat)abstract
- Sequential carbohydrate synthesis is important for plant survival because it guarantees energy supplies for growth and development during plant ontogeny and reproduction. Starch and fructan are two important carbohydrates in many flowering plants and in human diets. Understanding this coordinated starch and fructan synthesis and unraveling how plants allocate photosynthates and prioritize different carbohydrate synthesis for survival could lead to improvements to cereals in agriculture for the purposes of greater food security and production quality. Here, we report a system from a single gene in barley employing two alternative promoters, one intronic/exonic, to generate two sequence-overlapping but functionally opposing transcription factors, in sensing sucrose, potentially via sucrose/glucose/fructose/trehalose 6-phosphate signaling. The system employs an autoregulatory mechanism in perceiving a sucrose-controlled trans activity on one promoter and orchestrating the coordinated starch and fructan synthesis by competitive transcription factor binding on the other promoter. As a case in point for the physiological roles of the system, we have demonstrated that this multitasking system can be exploited in breeding barley with tailored amounts of fructan to produce healthy food ingredients. The identification of an intron/exon-spanning promoter in a hosting gene, resulting in proteins with distinct functions, adds to the complexity of plant genomes. ERYSTWYTH, WALES, V123, P453
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| 4. |
- Jin, Yunkai, et al.
(författare)
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New Energy Crops for Biofuel Production
- 2015
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Ingår i: Handbook of clean energy systems. - Chichester, UK : John Wiley & Sons, Ltd. - 9781118388587 ; , s. 49-62
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Bokkapitel (refereegranskat)
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| 5. |
- Jin, Yunkai, et al.
(författare)
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T-6b allocates more assimilation product for oil synthesis and less for polysaccharide synthesis during the seed development of Arabidopsis thaliana
- 2017
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Background: As an Agrobacterium tumefaciens T-DNA oncogene, T-6b induces the development of tumors and the enation syndrome in vegetative tissues of transgenic plants. Most of these effects are related to increases in soluble sugar contents. To verify the potential roles of T-6b in the distribution of carbon in developing seeds, not in vegetative tissues, we fused an endosperm-specific promoter to the T-6b gene for expression in transgenic Arabidopsis thaliana plants.Results: The expression of T-6b in reproductive organs did not induce the development of the enation syndrome, and moreover, promoted endosperm expansion, which increased the total seed biomass by more than 10%. Additionally, T-6b also increased oil content in mature seeds by more than 10% accompanied with the decrease of starch and mucilage content at the same time.Conclusions: T-6b enhances seed biomass and helps oil biosynthesis but not polysaccharides in reproductive organs without disturbing vegetative growth and development. Our findings suggest T-6b may be very useful for increasing oil production in biodiesel plants.
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| 6. |
- Källman, Anna, et al.
(författare)
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Starch structure in developing barley endosperm
- 2015
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier BV. - 0141-8130 .- 1879-0003. ; 81, s. 730-735
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Tidskriftsartikel (refereegranskat)abstract
- Barley spikes of the cultivars/breeding lines Gustav, Karmose and SLU 7 were harvested at 9, 12 and 24 days after flowering in order to study starch structure in developing barley endosperm. Kernel dry weight, starch content and amylose content increased during development. Structural analysis was performed on whole starch and included the chain-length distribution of the whole starches and their beta-limit dextrins. Karmose, possessing the amo1 mutation, had higher amylose content and a lower proportion of long chains (DP >= 38) in the amylopectin component than SLU 7 and Gustay. Structural differences during endosperm development were seen as a decrease in molar proportion of chains of DP 22-37 in whole starch. In beta-limit dextrins, the proportion of B-fp-chains (DP 4-7) increased and the proportion of BSmajor-chains (DP 15-27) decreased during development, suggesting more frequent activity of starch branching enzymes at later stages of maturation, resulting in amylopectin with denser structure. (C) 2015 Elsevier B.V. All rights reserved.
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| 7. |
- Su, Jun, et al.
(författare)
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Expression of barley SUSIBA2 transcription factor yields high-starch low-methane rice
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 523, s. 602-606
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric methane is the second most important greenhouse gas after carbon dioxide, and is responsible for about 20% of the global warming effect since pre-industrial times(1,2). Rice paddies are the largest anthropogenic methane source and produce 7-17% of atmospheric methane(2,3). Warm waterlogged soil and exuded nutrients from rice roots provide ideal conditions for methanogenesis in paddies with annual methane emissions of 25-100-million tonnes(3,4). This scenario will be exacerbated by an expansion in rice cultivation needed to meet the escalating demand for food in the coming decades(4). There is an urgent need to establish sustainable technologies for increasing rice production while reducing methane fluxes from rice paddies. However, ongoing efforts for methane mitigation in rice paddies are mainly based on farming practices and measures that are difficult to implement(5). Despite proposed strategies to increase rice productivity and reduce methane emissions(4,6), no high-starch low-methane-emission rice has been developed. Here we show that the addition of a single transcription factor gene, barley SUSIBA2 (refs 7, 8), conferred a shift of carbon flux to SUSIBA2 rice, favouring the allocation of photo-synthates to aboveground biomass over allocation to roots. The altered allocation resulted in an increased biomass and starch content in the seeds and stems, and suppressed methanogenesis, possibly through a reduction in root exudates. Three-year field trials in China demonstrated that the cultivation of SUSIBA2 rice was associated with a significant reduction in methane emissions and a decrease in rhizospheric methanogen levels. SUSIBA2 rice offers a sustainable means of providing increased starch content for food production while reducing greenhouse gas emissions from rice cultivation. Approaches to increase rice productivity and reduce methane emissions as seen in SUSIBA2 rice may be particularly beneficial in a future climate with rising temperatures resulting in increased methane emissions from paddies(9,10).
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| 8. |
- Sun, Chuanxin
(författare)
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A simple and efficient method for potential point-of-care diagnosis of human papillomavirus genotypes: combination of isothermal recombinase polymerase amplification with lateral flow dipstick and reverse dot blot
- 2019
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 411, s. 7451-7460
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Tidskriftsartikel (refereegranskat)abstract
- Cervical cancer is the second most common cancer in the world's woman population with a high incidence in developing countries where diagnostic conditions for the cancer are poor. The main culprit causing the cancer is the human papillomavirus (HPV). HPV is divided into three major groups, i.e., high-risk (HR) group, probable high-risk (pHR) group, and low-risk (LR) group according to their potential of causing cervical cancer. Therefore, developing a sensitive, reliable, and cost-effective point-of-care diagnostic method for the virus genotypes in developing countries even worldwide is of high importance for the cancer prevention and control strategies. Here we present a combined method of isothermal recombinase polymerase amplification (RPA), lateral flow dipstick (LFD), and reverse dot blot (RDB), in quick point-of-care identification of HPV genotypes. The combined method is highly specific to HPV when the conserved L1 genes are used as targeted genes for amplification. The method can be used in identification of HPV genotypes at point-of-care within 1 h with a sensitivity of low to 100 fg of the virus genomic DNA. We have demonstrated that it is an excellent diagnostic point-of-care assay in monitoring the disease without time-consuming and expensive procedures and devices.
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| 9. |
- Sun, Chuanxin
(författare)
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Carboxyl-Functionalized, Europium Nanoparticle-Based Fluorescent Immunochromatographic Assay for Sensitive Detection of Citrinin in Monascus Fermented Food
- 2019
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Ingår i: Toxins. - : MDPI AG. - 2072-6651. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- A fluorescent immunochromatographic test strip (FICTS) based on the use of europium nanoparticles (EuNPs) was developed and applied to detect citrinin (CIT) in Monascus fermented food. The sensitivity of the immunoassay to detect CIT was greatly improved by the use of a specific monoclonal antibody to attach EuNPs to form a probe. Under optimum conditions, the visual detection limit was 2.5 ng/mL, and the detection limit of the instrument was 0.05 ng/mL. According to the results, the IC50 was 0.4 ng/mL. Matrix interference from various Monascus fermented foods was investigated in food sample detection. The immunosensor also demonstrated high recoveries (86.8-113.0%) and low relative standard deviations (RSDs) (1.8-15.3%) when testing spiked Monascus fermented food. The detection results of this method showed a good correlation (R-2 > 0.98) with high-performance liquid chromatography (HPLC). The results showed that the FICTS method could be used as a rapid, sensitive method to detect CIT in Monascus fermented food.
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| 10. |
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