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[Display omitted] • Recombinant patatin was expressed in P. pastoris. • The titre reached 2189.8 mg/L in a 5 L bioreactor. • Genetic engineering enhanced the level of N -glycosylation. • N -glycosylation improved foaming, hydrophobicity and emulsifying properties. • N -glycosylation enhanced gel water-holding capacity and lowered gel temperature. Patatin is an acidic protein found in potatoes that is commonly used in food and pharmaceutical industries due to its excellent emulsifying and gelation abilities. Pichia pastoris is widely used as a host for recombinant protein production because it can incorporate post-translational modifications. In this study, a patatin titre of 2189.8 mg/L was achieved in a 5 L bioreactor using P. pastoris GS115 with signal peptide mutation, dual promoter construction, co-expression of chaperone proteins and optimised fermentation. To enhance the application of recombinant patatin in the food processing field, the level of N -glycosylation was elevated by genetic engineering. Properties of natural patatin, recombinant patatin and patatinL109T (N -glycosylated modified patatin) were investigated including foaming, hydrophobicity and emulsifying abilities. The functional properties of recombinant patatin were enhanced by introducing N -glycosylation, which also improved the water-holding capacity of its gel. The patatinL109T gel exhibited superior elasticity and water retention properties. The findings provide valuable insight and serve as a reference for the utilisation of recombinant patatin. The established enhancement strategy could be applied to other recombinant proteins. [ABSTRACT FROM AUTHOR]

In massive multiple-input multiple-output (MIMO) systems, a multi-antenna eavesdropper could potentially harm the uplink security by channel estimation in the training phase and then coherent detection in the payload data phase. To address this issue, we propose to inject artificial noise to the payload data to combat eavesdropping. Specifically, lower bounds of secrecy rates for maximum-ratio combining (MRC) and zero-forcing (ZF) detection schemes are derived. In each case, we further investigate scenarios with perfect and imperfect channel-state information. Moreover, the impact of key parameters, including the channel estimation error, power allocation factor and the number of antennas on the security of massive MIMO uplink are discussed. [ABSTRACT FROM AUTHOR]

Herbivore attack is a major type of biotic stress that greatly affects the development and quality of tea plant [ Camellia sinensis (L) O. Kuntze]. Tea plant produces many glycosylated compounds that enhance resistance to herbivores. An example is quercetin, one of the major flavonols of tea plants, which was glycosylated to involve responses to various environmental stresses. However, not much is known about the biosynthesis of glycosylated quercetin derivatives in tea plant in response to herbivorous attack. Here, we found that E. grisescens attack significantly increased the contents of quercetin 3- O -glucoside and quercetin 7- O -glucoside in tea leaves, and exogenous application of these two compounds improved the E. grisescens resistance of tea plant. Integrated transcriptome and phylogenetic analyses identified CsUGT95B11 gene, encoding a quercetin glycosyltransferase, which was upregulated in response to E. grisescens attack. Enzymatic assays showed that CsUGT95B11 preferentially glycosylated quercetin to produce quercetin 7- O -glucoside with a k cat · K m −1 value of 9655.52 M−1 s−1. Subcellular localization analysis indicated that CsUGT95B11 was dispersed in the cytoplasm of Nicotiana benthamiana leaves and Arabidopsis protoplast. Suppression of CsUGT95B11 reduced the quercetin glucoside content of tea leaves and impaired resistance of tea plant to E. grisescens. These results indicate that CsUGT95B11 is a quercetin glycosyltransferase that enhances resistance of tea plant to E. grisescens , providing insights into the mechanism of flavonol glycosylation regulating interactions between plants and herbivores. • E. grisescens feeding induced increase in quercetin glucoside content and expression of CsUGT95B11 in tea leaves. • Exogenous application of quercetin glucosides enhanced the resistance of tea plant against E. grisescens. • CsUGT95B11 preferably glycosylated quercetin to produce quercetin 3- O -glucoside and quercetin 7- O -glucoside in vitro. • CsUGT95B11 localized in cytoplasm. • Suppression of CsUGT95B11 reduced quercetin glucoside content and impaired resistance of tea plant against E. grisescens. [ABSTRACT FROM AUTHOR]

The HfO 2 -based ferroelectrics have aroused considerable attention due to their potential application in silicon process-compatible memory devices. However, the ferroelectricity origin and the domain evolution have not yet been well understood. It is now generally accepted the orthorhombic Pca 2 1 phase is one of ferroelectric phases for HfO 2. In this work, by performing density functional theory calculations, we systematically studied the domain wall structures and evolution based on the Pca 2 1 ferroelectric phase. More specifically, the atomic structures of ten types of possible 180° and 90° ferroelectric domain walls are predicted and explored. And the motion of certain domain walls is expected as the microscopic mechanisms of the polarization switching and ferroelectricity activation of Pca 2 1 HfO 2 under external electric field. Our results are in good agreement with the recent experimental results on ferroelectric domain walls in HfO 2 -based epitaxial thin-film and are helpful to understand the ferroelectricity origin of the HfO 2 -based ferroelectrics. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Heme oxygenase-1 (HO-1) has anti-inflammatory effects on myeloid cells in response to various stimuli. To date, little is known about whether fatty acids can affect HO-1 induction. Here, we report the induction of HO-1 by docosahexaenoic acid (DHA) and the associated molecular mechanisms in human myelomonocytic lymphoma U937 cells. When U937 cells were treated with DHA, eicosapentaenoic acid, palmitic acid or oleic acid, DHA was the most effective inducer of HO-1. The activation of AKT and glycogen synthase kinase-3β did not significantly change after DHA treatment. However, DHA increased the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), but not of other mitogen-activated protein kinases such as p38 and JNK. The increase in HO-1 expression was significantly inhibited by U0126, an ERK1/2 inhibitor. Nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf-2) and its binding to the HO-1 promoter significantly increased upon DHA treatment. An increase in intracellular reactive oxygen species was detected by dichlorofluorescein diacetate, but not by hydroethidium or 2-[6-(4-hydroxy)phenoxy-3H-xanthen-3-on-9-yl] benzoic acid after DHA treatment. Pretreatment with NAC dramatically inhibited the ERK1/2 activation, binding of Nrf-2 to antioxidant response elements (AREs) located in the HO-1 promoter and the induction of HO-1 by DHA. In conclusion, DHA increased HO-1 expression in U937 cells via activation of ERK1/2 and increased Nrf-2 binding to ARE in the HO-1 promoter. These findings will help develop better strategies for treating inflammatory disorders with DHA. [ABSTRACT FROM AUTHOR]