1,723,718 research outputs found
Role of transcription factors in storage lipid accumulation in plants
No full textWith few exceptions, seeds oil accumulates as triacylglycerols; three fatty acid molecules esterified to a glycerol backbone. The synthesis of normal fatty acids and unusual fatty acids, their assembly into triacylglycerols and subsequent packaging to form oil bodies have been reviewed elsewhere, and appear as separate contributions to the AOCS Lipid Library by Harwood, Hildebrand, Weselake et al., and Huang, respectively. These processes are highly regulated, involving spatial compartmentalization between different organelles and the exquisite control of several biosynthetic steps by one or more of a variety of biochemical mechanisms. The important role of transcriptional regulation towards seed oil accumulation has recently emerged. Not only are mRNA levels of many genes involved in seed oil biosynthesis coordinated during seed development, but altering the levels of certain transcription factors can affect the expression of multiple lipid biosynthetic genes, resulting in altered seed oil content. This article reviews salient features of plant transcription factors that have been implicated in the control of seed oil deposition. To set the stage, fundamental concepts in transcription factor biology are first summarized. Subsequently, the role of key transcription factors is highlighted by describing seed oil phenotypes associated with altering their expression levels by mutagenesis or transgenic means, and providing information on the putative target genes and pathways affected. The location of the transcription factors in hierarchical cascades and the modes of transcriptional regulation are also discussed, when this information is known. A summary of the information presented is depicted in Figure 1.NRC publication: Ye
Application of the Systems Engineering methodology to the design of the AOCS of an Earth Observation satellite
Full text linkThis document describes the application of enhanced functional flow block diagrams (eFFBD) on the attitude and orbital control system (AOCS) of an Earth Observation satellite. First requirements and constraints of the satellite and its mission have been identified. Afterwards, these requirements and constraints were used to design the eFFBD of the AOCS
Predicting the oxidative stability in bakery products: application of accelerated method based on oxygen consumption
No full textModelling and Simulation ofGNC/AOCS Systemsfor Conceptual Studies
No full textThe preliminary design of Guidance, Navigation, and Control (GNC) algorithms andAttitude and Orbital Control Systems (AOCS) for spacecraft plays an important rolein the planning of a space mission. Many missions require accurate positioning andattitude control to be able to full the mission objectives. In an early phase of conceptualstudies, trade-os have to be made to the GNC/AOCS subsystem designand compromises with respect to other subsystem designs have to be taken intoaccount. This demands for the possibility of rapid prototyping where design parameters,such as the choice of sensors and actuators, can be changed easily to assessthe compliance to the mission requirements. This thesis presents the modelling ofGNC/AOCS components for a toolbox created in the MATLAB/Simulink environment.The resulting toolbox is a user-friendly tool, which simplies the creationof GNC/AOCS system simulations for conceptual studies. A number of completesimulations were constructed to demonstrate the capabilities of the toolbox
The nonlinear effect of alkyl chain length of phenolipids in the membrane interactions and oxidation: evidence by X-ray diffraction analysis
Full text linkPhenolics represent a large family of secondary metabolites, ubiquitous in the plant kingdom and highly diversified. Although under native form they are effective antioxidants, their hydrophilic nature may be sometimes prejudicial to their antioxidant efficacy. Indeed, in complex systems such as emulsions, membranes, and living cells, it is generally considered advantageous for antioxidants to exhibit surface-active properties. One strategy to obtain surface-active phenolics consists in their association via covalent bond with a lipophilic moiety to design a new class of molecule called “phenolipids”. As tailor-made new bioactive molecules, the phenolipids have proved to be a promising way to enhance their natural antioxidant property. This grafted lipophilic domain kinetically modulated the ability of the phenolipid to interact and cross cell membranes. Despite the evidence supporting a relationship between phenolipid's alkyl chain length and their interaction/affinity with membrane bilayer, such a relationship has not been directly visualized. In this study, the membrane interactions of rosmarinic acid, considered as one of the most efficient antioxidant, and its corresponding alkyl esters have been examined via small angle x-ray (SAXS) diffraction approach in model membrane liposomes and correlate with the overall peroxidation of the membrane
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