Migration of l-Selenomethionine in the Water-Soil Interface Dominated by Iron Oxides.

Organic selenium (Se) accounts for up to 10-80% of total Se in soils, and l-selenomethionine (SeMet) is a typical organic Se species. However, the migration of SeMet in soils remains elusive. This study investigated the solid-liquid distribution, adsorption, desorption by phosphate, and self-oxidization of SeMet in solution under the influence of ferrihydrite, goethite, and hematite through batch experiments. Iron oxides could adsorb a much larger amount of SeMet than inorganic Se. At the initial Se element concentrations of 0-200 mg/L, the solid/liquid partition coefficient of SeMet was constant, which was 0.41, 0.43, and 0.50 on ferrihydrite, goethite, and hematite, respectively. In addition, the adsorption process of SeMet on the three iron oxides could be well described by the linear driving force model. Accordingly, the intraparticle diffusion coefficient of SeMet in ferrihydrite, goethite, and hematite was 1.4 × 103, 7.9 × 104, and 1.2 × 105 nm2/min, respectively. The adsorption of SeMet on the three iron oxides was slightly influenced by the pH and the coexisting ions, such as Cl-, NO3-, SO42-, and H2PO4-. The desorption ratio of SeMet on the three iron oxides by phosphate was lower than 2.5%. SeMet would aggregate the nanoparticles of iron oxides, resulting in a synergistic effect on the adsorption of phosphate. The oxidization ratio of SeMet was 23.9% in the solution, while it decreased to 17.1-17.5% in iron oxide suspensions. For this oxidization process, the three iron oxides exhibited varying effects to decelerate SeMet oxidation, as represented by the equivalent reaction. The findings of this study reveal the migration of SeMet in the water-soil interface under the influence of iron oxides, which can improve the understanding of Se cycling in the environment as well as provide some guidance for the better utilization of Se in soils and environmental remediation of Se pollution.

Antiovarian cancer mechanism of esculetin: inducing G0/G1 arrest and apoptosis via JAK2/STAT3 signalling pathway.

OBJECTIVES: Esculetin is a coumarin derivative, which is extracted from the dried barks of fraxinus chinensis Roxb. Although it is reported esculetin possesses multiple pharmacological activities, its associated regulatory mechanism on ovarian cancer isn't well investigated. METHODS: Cytotoxicity is evaluated by MTT, clonogenic and living/dead cells staining assays. Migration and invasion effects are investigated by wound healing, and transwell assays. The effect of cell cycle and apoptosis are analyzed by flow cytometry and western blotting. Mitochondrial membrane potential and intracellular reactive oxygen species (ROS) is assessed by fluorescence microscope. Analysis of animal experiments are carried out by various pathological section assays. KEY FINDINGS: Esculetin exerts an anti- ovarian cancer effect. It is found that apoptosis induction is promoted by the accumulation of excessive ROS and inhibition of JAK2/STAT3 signalling pathway. In addition, exposure to esculetin leads to the cell viability reduction, migration and invasion capability decrease and G0/G1 phase cell cycle arrest induced by down-regulating downstream targets of STAT3. In vivo experimental results also indicate esculetin can inhibit tumour growth of mice. CONCLUSIONS: Our study provides some strong evidences to support esculetin as a potential anti-cancer agent in ovarian cancer.

Lentinan promotes the root of Brassica Campestris L.

The aim of this work was to study the effect of lentinan on Brassica campestris L (rape). Spraying on the leaves of lentinan B. campestris L. at 0.05×10-6 g ml-1 concentration significantly promoted the root elongation (P＜0.05). The results for the first time showed that lentinan could prolongate roots as a new plant hormone.