Introduction Improvement of root architecture is crucial to increasing nutrient acquisition. Methods Two pot experiments were conducted to investigate the effects of different concentrations of urea ...ammonium nitrate solution (UAN) and ammonium polyphosphate (APP) on lettuce root architecture and the relationship between roots and nitrogen (N) and phosphorus (P) absorption. Results The results showed that lettuce yield, quality, and root architecture were superior in the APP4 treatment compared to other P fertilizer treatments. The N480 treatment (480 mg N kg -1 UAN) significantly outperformed other N treatments in terms of root length, root surface area, and root volume. There were significant quantitative relationships between root architecture indices and crop uptake of N and P. The relationships between P uptake and root length and root surface area followed power functions. Crop N uptake was significantly linearly related to the length of fine roots with a diameter of <0.5 mm. Conclusion and discussion The length of fine roots played a more prominent role in promoting N absorption, while overall root size was more important for P absorption. APP has a threshold of 9.3 mg P kg -1 for stimulating the root system. Above this threshold, a rapid increase in root absorption of P. UAN can promote extensive growth of fine roots with a diameter less than 0.5 mm. Applying appropriate rates of APP and limiting UAN application to less than 400 mg N kg -1 can improve root architecture to enhance N and P absorption by lettuce. These results highlight a new possibility to improve nutrients use efficiency while maintaining high yields.
Human pluripotent stem cell-derived kidney organoids recapitulate developmental processes and tissue architecture, but intrinsic limitations, such as lack of vasculature and functionality, have ...greatly hampered their application. Here we establish a versatile protocol for generating vascularized three-dimensional (3D) kidney organoids. We employ dynamic modulation of WNT signaling to control the relative proportion of proximal versus distal nephron segments, producing a correlative level of vascular endothelial growth factor A (VEGFA) to define a resident vascular network. Single-cell RNA sequencing identifies a subset of nephron progenitor cells as a potential source of renal vasculature. These kidney organoids undergo further structural and functional maturation upon implantation. Using this kidney organoid platform, we establish an in vitro model of autosomal recessive polycystic kidney disease (ARPKD), the cystic phenotype of which can be effectively prevented by gene correction or drug treatment. Our studies provide new avenues for studying human kidney development, modeling disease pathogenesis, and performing patient-specific drug validation.
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•Modulation of WNT generates vascularized and segmentally patterned kidney organoids•Single-cell analysis identifies a non-conventional origin of renal vasculature•Structural and functional maturation of kidney organoids occurs upon implantation•Cystic kidney organoids from ARPKD iPSCs enable personalized drug validation
Human PSC-derived organoids are an amenable platform for understanding human development and diseases despite numerous limitations. Low et al. establish a versatile platform for generating vascularized and patterned kidney organoids. Using this platform, they identified a non-conventional origin of renal vasculature and recapitulated ARPKD cystogenesis in vitro.
Large-scale columnar jointed basalt (CJB) developments have had serious adverse effects on the stability of the project in progress to create the diversion tunnels at the Baihetan hydropower station ...in China. An in situ microseismic (MS) monitoring experiment was carried out to help understand the fracturing process in the CJB rock mass as a result of tunnel excavation. MS monitoring performance (accuracy of location estimation and system sensitivity) is analyzed first. Then, the spatiotemporal evolution of the MS activity associated with the Baihetan CJB rock mass fractures along the tunnel axis and at the tunnel sidewalls during the entire excavation unloading process is obtained. Finally, the forms and opportunities to deploy appropriate support are suggested according to the characteristics of the CJB microseismicity. Meanwhile, the MS monitoring methods required for CJB or jointed hard rock engineering (e.g. sensor types, sensor spacing, sensor array forms, system protection, and selection of analysis regions) resulting from this exploration experiment are summarized.
•An MS test is presented for understanding excavation-induced fracturing process in the CJB.•The MS monitoring method required for CJB or jointed hard rock engineering is summarized.•Spatiotemporal evolution of MS activity during excavation of Baihetan CJB tunnel is obtained.•Timely support is able to effectively smother the aging relaxation of CJB.•Forms and opportunities to deploy appropriate support are suggested.
Human pluripotent stem cell-derived kidney organoids offer unprecedented opportunities for studying polycystic kidney disease (PKD), which still has no effective cure. Here, we developed both ...in vitro and in vivo organoid models of PKD that manifested tubular injury and aberrant upregulation of renin-angiotensin aldosterone system. Single-cell analysis revealed that a myriad of metabolic changes occurred during cystogenesis, including defective autophagy. Experimental activation of autophagy via ATG5 overexpression or primary cilia ablation significantly inhibited cystogenesis in PKD kidney organoids. Employing the organoid xenograft model of PKD, which spontaneously developed tubular cysts, we demonstrate that minoxidil, a potent autophagy activator and an FDA-approved drug, effectively attenuated cyst formation in vivo. This in vivo organoid model of PKD will enhance our capability to discover novel disease mechanisms and validate candidate drugs for clinical translation.
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