Proanthocyanidins (PAs) play an important role in plant disease defense and have beneficial effects on human health. We isolated and characterized a novel R2R3 MYB-type PA-regulator SsMYB3 from a well-known ornamental plant, coleus (Solenostemon scutellarioides), to study the molecular regulation of PAs and to engineer PAs biosynthesis. The expression level of SsMYB3 was correlated with condensed tannins contents in various coleus tissues and was induced by wounding and light. A complementation test in the Arabidopsis tt2 mutant showed that SsMYB3 could restore the PA-deficient seed coat phenotype and activated expression of the PA-specific gene ANR and two related genes, DFR and ANS. In yeast two-hybrid assays, SsMYB3 interacted with the Arabidopsis AtTT8 and AtTTG1 to reform the ternary transcriptional complex, and also interacted with two tobacco bHLH proteins (NtAn1a and NtJAF13-1) and a WD40 protein, NtAn11-1. Ectopic overexpression of SsMYB3 in transgenic tobacco led to almost-white flowers by greatly reducing anthocyanin levels and enhancing accumulation of condensed tannins. This overexpression of SsMYB3 upregulated the key PA genes (NtLAR and NtANR) and late anthocyanin structural genes (NtDFR and NtANS), but downregulated the expression of the final anthocyanin gene NtUFGT. The formative SsMYB3-complex represses anthocyanin accumulation by directly suppressing the expression of the final anthocyanin structural gene NtUFGT, through competitive inhibition or destabilization of the endogenous NtAn2-complex formation. These results suggested that SsMYB3 may form a transcription activation complex to regulate PA biosynthesis in the Arabidopsis tt2 mutant and transgenic tobacco. Our findings suggest that SsMYB3 is involved in the regulation of PA biosynthesis in coleus and has the potential as a molecular tool for manipulating biosynthesis of PAs in fruits and other crops using metabolic engineering.
Conductive macroscopic MXene‐based architectures receive tremendous attention for various potential applications. In this paper, the rheology and printing suitability of MXene ink were optimized by ball milling method to ensure good structural integrity and electrical conductivity of the printing structure. Porous CNT/Ti3C2Tx/CS composites were prepared by 3D printing, and the effects of various arrangements on electromagnetic interference shielding (EMI SE) were studied in depth. Since Ti3C2Tx can produce TiO2 under the action of high‐energy ball milling, it provides more heterogeneous interfaces and dipole effects. At the same time, Ti3C2Tx and CNT are evenly dispersed and can construct a complete conductive network, which greatly enhances its conductivity loss. In collaboration with the 3D‐printed framework, it can also extend the propagation path of electromagnetic waves and enhance their multiple reflection losses. The results show that the EMI SE of the composite material can reach 26 dB in X‐band, and EMI SE can be affected by the different arrangement. This work lays a solid foundation for the construction of heterogeneous interfaces by ball milling and the free construction of EMI shielding materials by 3D printing.
Objective. Diabetic kidney disease (DKD) has been well recognized as a microvascular complication of diabetes mellitus. Perfusion of intrarenal arteries is closely related with development of DKD. The aim of the present study was to investigate relation of ultrasonography performance of intrarenal arteries and grade of DKD. Methods. From May to December at 2021, a total of 54 DKD patients and 36 non-DKD cases were recruited. Ultrasonography performance of intrarenal and arteries at lower extremity was examined by high-resolution ultrasound diagnostic equipment; maximum (Vsmax) as well as minimum (Vdmin) blood velocity of arteries were recorded, and resistance index (RI) of arteries were calculated. Blood routine and biochemical parameters were determined from clinical laboratory of our hospital. Results. According to eGFR grading, 42.50% of the 54 DKD cases are at Grade 1, and 18.52%, 11.11%, 9.26%, and 18.52% cases were at Grade 2, 3a, 3b, and 4-5, respectively. Blood urea and creatinine were significantly positively related with progress of DKD, while level of Hb was negatively related with DKD. By ultrasonography; we found that Vsmax and Vdmin of main renal artery (MRA), segmental renal artery (SRA), and interlobular renal artery (IRA) were significantly reduced compared with healthy cases; IR of the above arteries was dramatically elevated, and changes of the above data were more obvious than that of lower extremity. Vdmin of MRA, SRA, and IRA was negatively related with grading of DKD, while RI was positively related with the grading. Converging from RI and level of Hb, we found that the level of Hb is positively related with healthy status of the kidney, while RI of the arteries is negatively with that. Conclusions. Resistance index (RI) of intrarenal arteries, obtained from ultrasonography combining with level of hemoglobin (Hb), is the predictor of progress of DKD.
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