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Silicon (Si) can increase plant stress tolerance. Mercury (Hg) is one of the major elements of heavy metal pollution. However, little attention has been paid to the possible effect of Si on Hg toxi...

Background Esophageal cancer is a digestive tract malignancy, ranking sixth among the world's deadliest tumor incidence. However, the pathogenesis of esophageal cancer is complex and the prognosis remains poor. Therefore, in-depth study of the pathogenesis and developing effective treatments are of great value for esophageal cancer. β-elemene is a natural monomeric compound derived from the Chinese herbal Curcuma wenyujin. β-elemene has been reported to have anti-tumor effects and used as an adjunct to clinical therapy for multiple cancers. This study aims to explore the effects of β-elemene on esophageal cancer and its related molecular mechanisms. Methods TE-1 and KYSE-150 cells were used to evaluate the activity of β-elemene on esophageal cancerin vitro and in vivo. Western blot was performed for protein expression assessment. CCK8 assay and cell cycle analysis were used for proliferation testing. Flow cytometry was performed for apoptosis detection. Wound healing assay was subjected to assess the migration ability. Transwell chamber assay was applied to assess the invasion ability. HE staining, TUNEL staining and immunohistochemical staining were used to evaluate the changes in tumor tissues. Results We found that β-elemene treatment suppressed proliferation, as well as induced apoptosis of esophageal cancer cells. In addition, β-elemene inhibited the migration and invasion ability of esophageal cancer cells. Furthermore, β-elemene exerted its effects against esophageal cancer by specifically regulating AKT signaling, thereby controlling the expression of PD-L1. Conclusion β-elemene inhibits proliferation and metastasis of esophageal cancer cells by regulating the phosphorylation of AKT.

Aquaporin isoforms have distinct functions, and show differential responses to stress conditions among different plant species. In tomato (Solanum lycopersicum), the functions of individual aquaporin isoforms under environmental stresses remain largely unknown. As a step toward understanding their functions under stress conditions, the expression response of plasma membrane intrinsic proteins (PIPs) to salt stress was investigated. Tomato seedlings were subjected to 150 mM NaCl for 1 h and 24 h, and water uptake and SlPIP expressions were investigated. The results showed that the root hydraulic conductivity (Lpr) was decreased under salt stress. Salt stress for 1 h had no effect or increased the expressions of most of the highly expressed SlPIPs in roots and leaves. Salt stress inhibited cell-to-cell water transport. Protein phosphatase and endocytosis inhibitors partially inhibited the Lpr decrease under salt stress. After a 24-h salt stress, the expressions of most SlPIPs were decreased in both roots and leaves, and a recovery treatment in control nutrient solution demonstrated a partial or full expression restoration of most previously downregulated SlPIPs. The expressions of SlPIP isoforms highly varied in both roots and leaves, and across different stress durations. SlPIP1;1, SlPIP1;3, SlPIP1;7, SlPIP2;10 and SlPIP2;12 demonstrated consistent expression responses to salt stress and recovery treatment in both roots and leaves, implying their important roles in regulating water transport. Our results suggest that SlPIPs are involved in mediating water transport in tomato, and their regulations are associated with stress duration and tissue type. At early stage of salt stress, the inhibition of Lpr in tomato might be due to the decrease of SlPIP activity; while at later stress period, the Lpr reduction might be mainly attributed to the decrease of SlPIP expression.

Salinity decreases the yield and quality of crops. Silicon (Si) has been widely reported to have beneficial effects on plant growth and development under salt stress. However, the mechanism is still poorly understood. In an attempt to identify genes or gene networks that may be orchestrated to improve salt tolerance of cucumber plants, we sequenced the transcriptomes of both control and salt-stressed cucumber leaves in the presence or absence of added Si. Seedlings of cucumber ‘JinYou 1’ were subjected to salt stress (75 mM NaCl) without or with addition of 0.3 mM Si. Plant growth, photosynthetic gas exchange and transcriptomic dynamics were investigated. The results showed that Si addition improved the growth and photosynthetic performance of cucumber seedlings under salt stress. The comparative transcriptome analysis revealed that Si played an important role in shaping the transcriptome of cucumber: the expressions of 1469 genes were altered in response to Si treatment in the control conditions, and these genes were mainly involved in ion transport, hormone and signal transduction, biosynthetic and metabolic processes, and stress and defense responses. Under salt stress alone, 1482 genes with putative functions associated with metabolic processes and responses to environmental stimuli have changed their expression levels. Si treatment shifted the transcriptome of salt-stressed cucumber back to that of the control, as evidenced that among the 708 and 774 genes that were up- or down-regulated under salt stress, a large majority of them (609 and 595, respectively) were reverted to the normal expression levels. These results suggest that Si may act as an elicitor to precondition cucumber plants and induce salt tolerance. The study may help us understand the mechanism for silicon-mediated salt tolerance and provide a theoretical basis for silicon application in crop production in saline soils.

It is essential to remove 2,4-dichlorophenol (DCP) from solution. In this paper, wheat straw (WS) was modified by a cationic surfactant, cetyltrimethyl ammonium bromide (CTAB), to improve adsorption capacity for the removal of DCP from aqueous solutions in batch mode. Several experimental factors like initial pH, common salts concentration, contact time, solution temperature were evaluated. Solution pH within 4-9 was in favor of adsorption and common salts had slight effect on adsorption quantity. The adsorption capacity was up to 45.5 mg g–1 and the process was exothermic. Henry equation was better to fit the adsorption equilibrium data. DCP-loaded MWS can be regenerated by 0.1 mol L–1 NaOH. It was concluded that MWS may be good adsorbent to remove DCP from solution.