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101.
Properties and Biotechnological Applications of Acyl‐CoA:diacylglycerol Acyltransferase and Phospholipid:diacylglycerol Acyltransferase from Terrestrial Plants and Microalgae
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Yang Xu Kristian Mark P. Caldo Dipasmita Pal‐Nath Jocelyn Ozga M. Joanne Lemieux Randall J. Weselake Guanqun Chen 《Lipids》2018,53(7):663-688
Triacylglycerol (TAG) is the major storage lipid in most terrestrial plants and microalgae, and has great nutritional and industrial value. Since the demand for vegetable oil is consistently increasing, numerous studies have been focused on improving the TAG content and modifying the fatty‐acid compositions of plant seed oils. In addition, there is a strong research interest in establishing plant vegetative tissues and microalgae as platforms for lipid production. In higher plants and microalgae, TAG biosynthesis occurs via acyl‐CoA‐dependent or acyl‐CoA‐independent pathways. Diacylglycerol acyltransferase (DGAT) catalyzes the last and committed step in the acyl‐CoA‐dependent biosynthesis of TAG, which appears to represent a bottleneck in oil accumulation in some oilseed species. Membrane‐bound and soluble forms of DGAT have been identified with very different amino‐acid sequences and biochemical properties. Alternatively, TAG can be formed through acyl‐CoA‐independent pathways via the catalytic action of membrane‐bound phospholipid:diacylglycerol acyltransferase (PDAT). As the enzymes catalyzing the terminal steps of TAG formation, DGAT and PDAT play crucial roles in determining the flux of carbon into seed TAG and thus have been considered as the key targets for engineering oil production. Here, we summarize the most recent knowledge on DGAT and PDAT in higher plants and microalgae, with the emphasis on their physiological roles, structural features, and regulation. The development of various metabolic engineering strategies to enhance the TAG content and alter the fatty‐acid composition of TAG is also discussed. 相似文献
102.
Gmyr Robert Hinnenthal Kristian Kostitsyna Irina Kuhn Fabian Rudolph Dorian Scheideler Christian Strothmann Thim 《Natural computing》2020,19(2):375-390
Natural Computing - Motivated by the problem of manipulating nanoscale materials, we investigate the problem of reconfiguring a set of tiles into certain shapes by robots with limited computational... 相似文献
103.
A novel automatic tuning strategy is proposed. It is based on an experiment of very short duration, followed by simultaneous identification of LTI model parameters and an estimate of their error covariance. The parametric uncertainty model is subsequently exploited to design linear controllers with magnitude bounds on some closed‐loop transfer function of interest, such as the sensitivity function. The method is demonstrated through industrially relevant examples. Robustness is enforced through probabilistic constraints on the norms of the sensitivity function, while minimizing load disturbance integral error to ensure performance. To demonstrate the strength of the proposed method, identification for the mentioned examples is carried out under a high level of measurement noise. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
104.
105.
Mølhave K Gudnason SB Pedersen AT Clausen CH Horsewell A Bøggild P 《Ultramicroscopy》2007,108(1):52-57
Observations of carbon nanotubes under exposure to electron beam irradiation in standard transmission electron microscope (TEM) and scanning electron microscope (SEM) systems show that such treatment in some cases can cause severe damage of the nanotube structure, even at electron energies far below the approximate 100 keV threshold for knock-on damage displacing carbon atoms in the graphene structure. We find that the damage we observe in one TEM can be avoided by use of a cold finger. This and the morphology of the damage imply that water vapour, which is present as a background gas in many vacuum chambers, can damage the nanotube structure through electron beam-induced chemical reactions. Though, the dependence on the background gas makes these observations specific for the presently used systems, the results demonstrate the importance of careful assessment of the level of subtle structural damage that the individual electron microscope system can do to nanostructures during standard use. 相似文献
106.
In this paper, the automated spatially dependent regularization parameter selection framework for multi-scale image restoration is applied to total generalized variation (TGV) of order 2. Well-posedness of the underlying continuous models is discussed and an algorithm for the numerical solution is developed. Experiments confirm that due to the spatially adapted regularization parameter, the method allows for a faithful and simultaneous recovery of fine structures and smooth regions in images. Moreover, because of the TGV regularization term, the adverse staircasing effect, which is a well-known drawback of the total variation regularization, is avoided. 相似文献
107.
Kristian Olsson 《电气时代》2009,(6):58-60
安全是任何工厂的头等大事,人员伤亡更是令人无法接受。但是,安全的含义可能并不仅仅局限于对人员和设备实施必要的基本保护,如与安全相关事件的负面宣传可能会对相关企业造成极其深刻的影响,在某些情况下,甚至会影响到整个行业。随着工艺复杂性的不断增加,工厂使用不同制造商提供的不同系统,这就给保证整体安全水平提出了挑战。ABB相信,未来的安全系统不再是一个附带系统,虽然在设计和供应方面与其他系统分开在不同的工厂或工艺过程进行,但理应成为其集成的一部分。 相似文献
108.
Louise Albertsen Dr. Søren Østergaard Dr. Johan F. Paulsson Dr. Jens Chr. Norrild Prof. Kristian Strømgaard 《ChemMedChem》2013,8(9):1505-1513
The gut hormone peptide YY (PYY) is postprandially secreted from enteroendocrine L cells and is involved in the regulation of energy homeostasis. The N‐terminal truncated version PYY(3–36) decreases food intake and has potential as an anti‐obesity agent. The anorectic effect of PYY(3–36) is mediated through Y2 receptors in the hypothalamus, vagus, and brainstem regions, and it is well known that the C‐terminal tetrapeptide sequence of PYY(3–36) is crucial for Y2 receptor activation. The aim of this work was to develop a semisynthetic methodology for the generation of a library of C‐terminally modified PYY(3–36) analogues. By using an intein‐based expression system, PYY(3–29) was generated as a C‐terminal peptide α‐thioester. Heptapeptides bearing an N‐terminal cysteine and modifications at one of the four C‐terminal positions were synthesized in a 96‐well plate by parallel solid‐phase synthesis. In the plate format, an array of [Ala30]PYY(3–36) analogues were generated by ligation, desulfurization, and subsequent solid‐phase extraction. The generated analogues, in which either Arg33, Gln34, Arg35, or Tyr36 had been substituted with proteinogenic or non‐proteinogenic amino acids, were tested in a functional Y2 receptor assay. Generally, substitutions of Tyr36 were better tolerated than modifications of Arg33, Gln34, and Arg35. Two analogues showed significantly improved Y2 receptor selectivity; therefore, these results could be used to design new drug candidates for the treatment of obesity. 相似文献
109.
Agnar Holten Sivertsen Karsten Heia Kristian Hindberg Fred Godtliebsen 《Journal of food engineering》2012
Detection of objects embedded in tissue, using visible light, is difficult due to light scattering. The optical properties of the surrounding tissue will influence the spectral characteristics of the light interacting with the object, and the spectral signature observed from the object will be directly affected. A method for calibrating the spectral signature of small objects, embedded in translucent material, by the estimated local background spectrum is presented. The method is evaluated under industrial conditions in a new hyperspectral imaging system for automatic detection of nematodes in cod fillets. The system operates at a conveyor belt speed of 400 mm/s which meets the industrial required speed of assessing one fillet per second. The local calibration method reduces the number of spectra needed to be classified by 89.6%. For one or more false alarms in 60% of the fillets sampled after the trimming station, the Gaussian maximum likelihood classifier detects 70.8% and 60.3% of the dark and pale nematodes, respectively. This is better than what is previously reported using a higher resolution instrument on a slow moving conveyor belt, and comparable or better to what is reported for manual inspection under industrial conditions. 相似文献
110.