Synergistic action and mechanism of scoparone, a key bioactive component of Artemisia capillaris, and spirodiclofen against spider mites.

BACKGROUND: Plants have numerous defensive secondary metabolites to withstand insect attacks. Scoparone, which is extracted from the medicinal plant Artemisia capillaris, has potent acaricidal effects on Tetranychus cinnabarinus. Spirodiclofen, derived from a tetronic acid derivative, is a potent commercial acaricide that is extensively used globally. However, whether scoparone has synergistic effects when used in conjunction with spirodiclofen and the underlying synergistic mechanism remains unclear. RESULTS: Scoparone exhibited a potent synergistic effect when it was combined with spirodiclofen at a 1:9 ratio. Subsequently, cytochrome P450 monooxygenase (P450) activity, RNA-Seq and qPCR assays indicated that the enzyme activity of P450 and the expression of one P450 gene from T. cinnabarinus, TcCYP388A1, were significantly inhibited by scoparone and spirodiclofen + scoparone; conversely, P450 was activated in spirodiclofen-exposed mites. Importantly, RNAi-mediated silencing of the TcCYP388A1 gene markedly increased the susceptibility of spider mites to spirodiclofen, scoparone and spirodiclofen + scoparone, and in vitro, the recombinant TcCYP388A1 protein could metabolize spirodiclofen. Molecular docking and functional analyses further indicated that R117, which is highly conserved in Arachnoidea species, may be a vital specific binding site for scoparone in the mite TcCYP388A1 protein. This binding site was subsequently confirmed using mutagenesis data, which revealed that this binding site was the sole site selected by scoparone in spider mites over mammalian or fly CYP388A1. CONCLUSIONS: These results indicate that the synergistic effects of scoparone and spirodiclofen on mites occurs through the inhibition of P450 activity, thus reducing spirodiclofen metabolism. The synergistic effect of this potent natural product on the detoxification enzyme-targeted activity of commercial acaricides may offer a sustainable strategy for pest mite resistance management. © 2024 Society of Chemical Industry.

Stemness-related genes revealed by single-cell profiling of naïve and stimulated human CD34+ cells from CB and mPB.

BACKGROUND: Hematopoietic stem cells (HSCs) from different sources show varied repopulating capacity, and HSCs lose their stemness after long-time ex vivo culture. A deep understanding of these phenomena may provide helpful insights for HSCs. METHODS: Here, we applied single-cell RNA-seq (scRNA-seq) to analyse the naïve and stimulated human CD34+ cells from cord blood (CB) and mobilised peripheral blood (mPB). RESULTS: We collected over 16 000 high-quality single-cell data to construct a comprehensive inference map and characterised the HSCs under a quiescent state on the hierarchy top. Then, we compared HSCs in CB with those in mPB and HSCs of naïve samples to those of cultured samples, and identified stemness-related genes (SRGs) associated with cell source (CS-SRGs) and culture time (CT-SRGs), respectively. Interestingly, CS-SRGs and CT-SRGs share genes enriched in the signalling pathways such as mRNA catabolic process, translational initiation, ribonucleoprotein complex biogenesis and cotranslational protein targeting to membrane, suggesting dynamic protein translation and processing may be a common requirement for stemness maintenance. Meanwhile, CT-SRGs are enriched in pathways involved in glucocorticoid and corticosteroid response that affect HSCs homing and engraftment. In contrast, CS-SRGs specifically contain genes related to purine and ATP metabolic process, which is crucial for HSC homeostasis in the stress settings. Particularly, when CT-SRGs are used as reference genes for the construction of the development trajectory of CD34+ cells, lymphoid and myeloid lineages are clearly separated after HSCs/MPPs. Finally, we presented an application through a small-scale drug screening using Connectivity Map (CMap) against CT-SRGs. A small molecule, cucurbitacin I, was found to efficiently expand HSCs ex vivo while maintaining its stemness. CONCLUSIONS: Our findings provide new perspectives for understanding HSCs, and the strategy to identify candidate molecules through SRGs may be applicable to study other stem cells.

Fabrication, modification and application of lipid nanotubes.

The potential application of high aspect-ratio nanomaterials motivates the development of the fabrication and modification of lipid nanotubes(LNTs). To date, diverse fabricate processes and elaborate template procedures have produced suitable tubular architectures with definite dimensions and complex structures for expected functions and applications. Herein, we comprehensively summarize the fabrication of LNTs in vitro and discuss the progress made on the micro/nanomaterials fabrication using LNTs as a template, as well as the functions and possible application of a wide range of LNTs as fundamental or derivative material. In addition, the characteristics, advantages, and disadvantages of different fabrication, modification methods, and development prospects of LNTs were briefly summarized.

Study on different particulate matter retention capacities of the leaf surfaces of eight common garden plants in Hangzhou, China.

The severity of inhalable particulate matter (PM) pollution in the atmosphere is increasing; however, plants can effectively reduce the concentration of atmospheric PM by retaining it on their leaves. In this paper, eight common garden plants in Hangzhou, China, were selected as the study objects to observe the morphological features of the leaf surfaces and the retained particles and to analyze the elemental composition of the particles. Confocal laser scanning microscopy (CLSM) was performed to detect the morphological features of the leaf surfaces, and the relationship between the roughness of the leaf surface and the number of the retained particulates was quantitatively analyzed. In addition, the elements in the soil were measured via inductively coupled plasma-optical emission spectrometry (ICP-OES) to locate the possible particulate sources. The results revealed that leaves are able to retain particulates via the synergy of multiple microstructures on the leaf surface, such as grooves, folds, small chambers, flocculus projections, long villi, pubescent hairs and waxes. Moreover, the leaf surface roughness is closely related to the number of retained particulates, with rougher surfaces corresponding to more rugged folds and grooves and a stronger retention ability. The retained particulates are primarily composed of C, O, Si, Al, Ca, K, Mg, Nb, Fe, Na and Ti, and a comparison with the elements in the soil samples indicated that these elements originated from soil dust. Among the different particle sizes, PM with a diameter <2.5 µm (PM2.5) presented the greatest retention on the surfaces of the different plant leaves, while a much smaller amount of PM with a diameter larger than 10 µm was retained. The research results provide an important theoretical scientific basis for the mechanism underlying PM adsorption by plants and strategies for the reasonable selection of garden dust-retaining tree species.