The expression and binding properties of the rice WRKY68 protein in the Xa21-mediated resistance response to Xanthomonas oryzae pv. Oryzae

Plant WRKY transcription factors are involved in various physiological processes, including biotic and abiotic stress responses, as well as developmental processes. In this study, the expression patterns of the WRKY68 protein during interactions between rice 4021 containing the bacterial blight resistance gene Xa21 and Xanthomonas oryzae pv. oryzae（Xoo） were investigated. A possible modified form of the WRKY68 protein appeared in the Xa21-mediated disease resistance response, and its expression levels were similar in compatible and incompatible responses, but differed significantly from that of the mock control treatment, suggesting that WRKY68 may be involved in the bacterial blight response in rice. To further understand WRKY68＇s roles in the resistance signaling pathway, WRKY68 recombinant protein was expressed in Escherichia coli and a microscale thermophoresis analysis was performed to investigate the interactions between WRKY68 and cis-elements in crucial pathogenesis-related（PR） genes. The results showed that the WRKY68 protein binds to W-boxes in the PR1 b promoter region, with an apparent dissociation constant of 25 nmol L–1, while the binding between WRKY68 and PR10 a was W-box independent. The results suggested that a possible modified form of the WRKY68 protein was induced during the interaction between rice and Xoo, which then regulated the activity of the downstream PR genes by binding with the W-boxes in the PR1 b gene＇s promoter region. Moreover, the constitutive transcription of the WRKY68 gene in dozens of rice tissues and the expression of the WRKY68 protein in leaves during all growth stages suggests that WRKY68 plays important roles in rice during normal growth processes.

分子光谱成像对玉米粉中微塑料的深度无损表征

目的采用不同的光谱成像方法对玉米粉中的微塑料进行原位无损表征,并通过化学计量学优化其成像效果。方法尝试利用光热共振红外光谱成像和共聚焦拉曼光谱成像两种分子光谱技术,结合化学计量学方法对玉米粉中微塑料的存在进行深入表征。结果光热共振红外成像方法能够快速获取样品中污染物存在信息,但数据完整性和可视化方面受到一定限制。通过对拉曼光谱图像数据降解,应用独立成分分析可以得到玉米粉中微塑料清晰的分布轮廓。此外,光热红外成像能够在低浓度水平上得到污染物的分布图像,但检出率不高(10%),具有快捷检测特点。拉曼光谱成像受到扫描速度的影响,在低浓度污染样品中检出较少,但在中浓度污染样品得到了30%的检出率,并得到了较好的可视化效果。结论通过分子光谱成像技术串联数据挖掘方法可以实现对粉状食品中微塑料的可视化检测,为食品中微塑料的无损便捷检测提供方法参考。

Self-assembling, pH-responsive nanoflowers for inhibiting PAD4 and neutrophil extracellular trap formation and improving the tumor immune microenvironment

Self-assembling carrier-free nanodrugs are attractive agents because they accumulate at tumor by an enhanced permeability and retention(EPR) effect without introduction of inactive substances,and some nanodrugs can alter the immune environment. We synthesized a peptidyl arginine deiminase 4(PAD4) molecular inhibitor, ZD-E-1 M. It could self-assembled into nanodrug ZD-E-1. Using confocal laser scanning microscopy, we observed its cellular colocalization, PAD4 activity and neutrophil extracellular traps(NETs) formation. The populations of immune cells and expression of immune-related proteins were determined by single-cell mass cytometry. ZD-E-1 formed nanoflowers in an acidic environment, whereas it formed nanospheres at pH 7.4. Accumulation of ZD-E-1 at tumor was pHresponsive because of its pH-dependent differences in the size and shape. It could enter the nucleus and bind to PAD4 to prolong the intracellular retention time. In mice, ZD-E-1 inhibited tumor growth and metastasis by inhibiting PAD4 activity and NETs formation. Besides, ZD-E-1 could regulate the ratio of immune cells in LLC tumor-bearing mice. Immunosuppressive proteins like LAG3 were suppressed,while IFN-γ and TNF-a as stimulators of tumor immune response were upregulated. Overall, ZD-E-1 is a self-assembling carrier-free nanodrug that responds to pH, inhibits PAD4 activity, blocks neutrophil extracellular traps formation, and improves the tumor immune microenvironment.

Light-induced irreversible structural phase transition in trilayer graphene

A crystal structure has a profound influence on the physical properties of the corresponding material.By synthesizing crystals with particular symmetries,one can strongly tune their properties,even for the same chemical configuration(compare graphite and diamond,for instance).Even more interesting opportunities arise when the structural phases of crystals can be changed dynamically through external stimulations.Such abilities,though rare,lead to a number of exciting phenomena,such as phase-change memory effects.In the case of trilayer graphene,there are two common stacking configurations(ABA and ABC)that have distinct electronic band structures and exhibit very different behaviors.Domain walls exist in the trilayer graphene with both stacking orders,showing fascinating new physics such as the quantum valley Hall effect.Extensive efforts have been dedicated to the phase engineering of trilayer graphene.However,the manipulation of domain walls to achieve precise control of local structures and properties remains a considerable challenge.Here,we experimentally demonstrate that we can switch from one structural phase to another by laser irradiation,creating domains of different shapes in trilayer graphene.The ability to control the position and orientation of the domain walls leads to fine control of the local structural phases and properties of graphene,offering a simple but effective approach to create artificial two-dimensional materials with designed atomic structures and electronic and optical properties.