[Accumulation, Migration, and Transformation of Soil Phosphorus in Facility Agriculture and Its Influencing Factors].

The aim of this study was to apply phosphorus fertilizer scientifically and reasonably and reduce the pollution risk to the facility agricultural environment. Taking the facility agriculture concentration area in Daxing District of Beijing as the research object, the phosphorus content in soil (0-100 cm) of the facility agriculture profile with different planting years was measured and analyzed to explore the characteristics of phosphorus accumulation, migration, and transformation. The results showed that the contents of total phosphorus and available phosphorus in the surface soil of facility agriculture varied widely, which was significantly higher than that in the surrounding grain field soil, which was mainly related to the amount of phosphorus applied by farmers in different planting years. With the increase in soil depth, the contents of total phosphorus and available phosphorus decreased gradually, showing surface aggregation ω (total phosphorus) ranging from 0.38 to 2.58 g·kg-1 and ω (available phosphorus) ranging from 1.60 to 256.00 mg·kg-1. With the increase in planting years, the contents of soil total phosphorus and available phosphorus first increased and then decreased, reached a peak in approximately 15 years, then gradually decreased, tended to be stable, and generally remained at a high level. Inorganic phosphorus was mainly concentrated in the surface soil of the facility agriculture, in which Ca-P accounted for the largest proportion of inorganic phosphorus, up to 98.38%; Ca10-P was the main form of Ca-P, up to 78.70% of Ca-P, and Ca2-P accounted for the smallest proportion, only 9.50% of Ca-P. The contents of different forms of inorganic phosphorus showed the vertical distribution characteristics of enrichment in the surface soil and a decrease downward. There were differences in the proportion of different forms of inorganic phosphorus to total phosphorus in different soil depths, in which the change in Ca-P was obvious, whereas the change in Fe-P and 0-P was not significant, indicating that the migration and transformation of Fe-P and O-P in the facility agricultural soil was poor, and the migration and transformation of inorganic phosphorus was mainly Ca-P. According to the correlation and path analysis, the direct path coefficient of Ca2-P to available phosphorus was the largest (0.787), which was not only the main source of soil available phosphorus but also the main form of inorganic phosphorus migration and transformation. Under the condition of protected cultivation, soil phosphorus showed a large accumulation trend, the availability of Ca10-P was low, and the accumulation was large. How to improve this portion of phosphorus sources is the key to the management of protected soil phosphorus.

Mu-Xiang-You-Fang protects PC12 cells against OGD/R-induced autophagy via the AMPK/mTOR signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Mu-Xiang-You-Fang (MXYF) is a classic prescription of Hui medicine. It is composed of five herbs and has been used to treat ischemic stroke for many years. However, the potential pharmacological mechanisms of MXYF remain unclear. The present research is aimed to investigate the protective effect and possible mechanisms of MXYF treatment in an in vitro model of cerebral ischemia-reperfusion injury. MATERIALS AND METHODS: An oxygen-glucose deprivation and reperfusion (OGD/R) model of PC12 cells was established. The effect of MXYF on the cell viability after OGD/R injury was determined using a cell counting kit (CCK-8) assay. The colorimetric method was used to determine the lactate dehydrogenase (LDH) leakage rate. The calcium concentration was determined by the chemical fluorescence method, and mitochondrial membrane potential was determined using flow cytometry. Monodansylcadaverine (MDC) staining and electron microscopic analysis were then conducted to detect autophagy after oxygen-glucose deprivation and reperfusion in PC12 cells. Immunofluorescence and western blot analyses were used to detect the expression of proteins associated with autophagy. RESULTS: It was found that MXYF (1, 2, 4 µg/mL) could significantly increase cell viability and mitochondrial membrane potential and decrease the calcium concentration and LDH release rate in PC12 cells. After OGD/R injury in PC12 cells, the number of autophagosomes and autophagolysosome significantly increased. MXYF (4 µg/mL) inhibited the autophagy induced by OGD/R and inhibited the expression of LC3, beclin1, p-AMPK, and ULK1. In contrast, the expression of p-mTOR, p-p70s6k, and p62 was significantly enhanced. CONCLUSIONS: These findings suggest that MXYF inhibits autophagy after OGD/R-induced PC12 cell injury through the AMPK-mTOR pathway. Thus, MXYF might have therapeutic potential in treating ischemic stroke.

[Inhibitory effect of flavonoids from Glycyrrhiza uralensis on expressions of TGF-ß1 and Caspase-3 in thioacetamide-induced hepatic fibrosis in rats].

OBJECTIVE: To study the inhibitory effect of flavonoids from Glycyrrhiza uralensis on thioacetamide-induced chonic hepatic fibrosis in rats and the effect on the protein expressions of transforming growth factor-ß1 (TGF-ß1) and Caspase-3 in livers. METHOD: Male Sprague-Dawley rats were randomly divided into totally seven groups: the normal control group, the model group, LF groups s (400, 200, 100, 50 mg · kg(-1) · d(-1)) and the silymarin positive control group (30 mg · kg(-1) · d(-1)). The hepatic fibrosis model was induced in the rats through intraperitoneal injection with 3% thioacetamide (TAA) at a dose of 150 mg · kg(-1) body weight twice a week for 12 weeks. During the course, the control group and the model group were orally administered with saline (1 mL · kg(-1) · d(-1)). After the modeling and drug intervention, the pathologic changes and fibrosis in liver tissues were observed by HE staining and Masson's Trichrome staining. The serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and liver hydroxyproline (HYP) contents were assayed by biochemical process. The serum hyaluronic acid (HA) was assessed by radioimmunoassay. In addition, the protein expressions of liver TGF-ß1 and Caspase-3 were examined by immunohistochemical method. The mRNA expression of TGF-ß1 in hepatic tissues was examined by quantitative Real-time PCR analysis. RESULT: Compared with the model group, flavonoids can protect the integrity of the structure of liver tissues, significantly reduce the hepatic cell degeneration and necrosis and the proliferation of fibrous tissues, notably reduce the serum AST, ALT, ALP and HA and HYP in hepatic tissues and down-regulate the protein expressions of liver TGF-ß1 and Caspase-3 and the mRNA expression of TGF-ß1 in hepatic tissues. CONCLUSION: The licorice flavonoids can resist the thioacetamide-induced hepatic fibrosis in rats. Its mechanism may be related to the down-regulation of the protein expressions of TGF-ß1 and Caspase-3.