[Interaction Effects of Vegetation and Soil Factors on Microbial Communities in Alpine Steppe Under Degradation].

To clarify the regulating effect of vegetation and soil factors on microbial communities in the alpine steppe under degradation on the Qinghai-Xizang Plateau, the alpine steppe in the Sanjiangyuan area of the Qinghai-Tibet Plateau was chosen. We analyzed the differences in vegetation and soil factors in different stages of degradation （non-degradation, moderate degradation, and severe degradation） and detected the variations in microbial community characteristics in the alpine steppe under different degradation stages using high-throughput sequencing technology. Eventually, redundancy analysis （RDA） and multiple regression matrixes （MRM） based on the similarity or dissimilarity matrix were used to identify key environmental factors regulating microbial （bacterial and fungal） community changes under degradation. The results showed that the degradation of the alpine steppe significantly changed the community coverage, height, biomass, and important value of graminae； significantly reduced the contents of soil organic matter, total nitrogen, total phosphorus, and silt； and increased the soil bulk density and sand content. Degradation did not change the composition of bacteria and fungi, but their composition proportions changed and also resulted in the loss of microbial richness （Chao1 index and Richness index） but did not significantly change the microbial diversity （Shannon index）. With the occurrence of degradation, the vegetation characteristics, soil physicochemical properties, and microbial diversity showed a consistent change trend. Combined with the characteristics of the network topology changes （the number of nodes and clustering coefficient significantly decreased）, it was found that degradation of the alpine steppe led to the decline of interspecies interactions, decentralization of network, and homogenization of microorganisms, but the cooperation relations among the species were maintained （positive correlation connections accounted for more than 90% in all degradation stages）. Under the alpine steppe degradation, the vegetation-soil interaction had the greatest effect on soil bacterial community, whereas soil physicochemical properties had the greatest influence on soil fungal community. Specifically, vegetation community height, biomass, and soil bulk density were the mutual factors regulating soil microorganisms, whereas the vegetation Simpson index, important value of graminae, soil total phosphorus, total potassium, and silt content were the unique factors affecting the soil bacterial community, and soil pH and total nitrogen content were the particular factors affecting the soil fungal community.

Repulsion, Acceleration, and Coalescence between Water Droplets on Superhydrophobic Glass by Triboelectrification.

Manipulating the motion of water droplets on surfaces, which is crucial for various applications, such as microfluidics and heat transfer, presents considerable challenges, primarily due to the significant influence of capillary forces. This effect becomes more pronounced when droplets are in close proximity, often resulting in undesired coalescence. Triboelectrification, which involves charging pure water droplets, is a promising approach to enhance the ability to manipulate water droplets. For effective triboelectrification, charges must accumulate within the droplets; this ensures efficient and sustained droplet manipulation while minimizing dissipation. Low-friction, superhydrophobic, insulating surfaces are ideal for this purpose. However, few studies have explored the application of insulating superhydrophobic surfaces to manipulate droplet motion. In this study, we investigated the behavior of water droplets on insulating superhydrophobic quartz surfaces after triboelectrification. The droplets acquired significant charge when dripped onto a superhydrophobic glass surface. Consequently, these charged droplets exhibited behaviors such as repulsion and acceleration from one another, uphill movement, and rapid long-distance transport to specific positions. These advancements in droplet manipulation techniques hold promise for diverse fields such as microfluidics and heat exchangers.

Indole alkaloids isolated from the Nicotiana tabacum-derived Aspergillus fumigatus 0338 as potential inhibitors for tobacco powdery mildew and their mode of actions.

To explore active natural products against tobacco powdery mildew caused by Golovinomyces cichoracearum, an extract from the fermentation of endophytic Aspergillus fumigatus 0338 was investigated. The mechanisms of action for active compounds were also studied in detail. As a result, 14 indole alkaloid derivatives were isolated, with seven being newly discovered (1-7) and the remaining seven previously described (8-14). Notably, compounds 1-3 are rare linearly fused 6/6/5 tricyclic prenylated indole alkaloids, with asperversiamide J being the only known natural product of this kind. The isopentenyl substitutions at the 5-position in compounds 4 and 5 are also rare, with only compounds 1-(5-prenyl-1H-indol-3-yl)-propan-2-one (8) and 1-(6-methoxy-5-prenyl-1H-indol3-yl)-propan-2-one currently available. In addition, compounds 6 and 7 are new framework indole alkaloid derivatives bearing a 6-methyl-1,7-dihydro-2H-azepin-2-one ring. The purified compounds were evaluated for their activity against G. cichoracearum, and the results revealed that compounds 7 and 9 demonstrated obvious anti-G. cichoracearum activities with an inhibition rate of 82.6% and 85.2%, respectively, at a concentration of 250 µg/mL, these rates were better than that of the positive control agent, carbendazim (78.6%). The protective and curative effects of compounds 7 and 9 were also better than that of positive control, at the same concentration. Moreover, the mechanistic study showed that treatment with compound 9 significantly increased the structural tightness of tobacco leaves and directly affect the conidiospores of G. cichoracearum, thereby enhancing resistance. Compounds 7 and 9 could also induce systemic acquired resistance (SAR), directly regulating the expression of defense enzymes, defense genes, and plant semaphorins, which may further contribute to increased plant resistance. Based on the activity experiments and molecular dockings, the indole core structure may be the foundation of these compounds' anti-G. cichoracearum activity. Among them, the indole derivative parent structures of compounds 6, 7, and 9 exhibit strong effects. Moreover, the methoxy substitution in compound 7 can enhance their activity. By isolating and structurally identifying the above indole alkaloids, new candidates for anti-powdery mildew chemical screening were discovered, which could enhance the utilization of N. tabacum-derived fungi in pesticide development.