[Availability Changes in Different Exogenous Selenium Fertilizers in Soil and Their Effects on Selenium Accumulation in Wheat].

In order to understand the differences in the uptake and accumulation of several common exogenous selenium fertilizers by crops, a wheat pot experiment was conducted to study the availability changes in different selenium fertilizers (potassium selenate, potassium selenite, EDTA-chelated selenium, selenium powder, fly ash, and selenium-enriched straw) in soil and their effects on wheat growth and selenium uptake and distribution. The results showed that the change in availability of different exogenous selenium types in soil was different. During the whole growth period of wheat, the soil available selenium proportion of selenate, selenite, and EDTA-chelated selenium treatment was significantly higher than that of the control (CK), respectively, but there was no significant difference between the other treatments and the CK treatment. In the early stage of wheat growth, the soil available selenium proportion of selenate, selenite, and selenium powder treatment decreased gradually and tended to be stable in the later growth stage of wheat; however, the soil available selenium proportion of other exogenous selenium treatments showed a dynamic change of decreasing in the early period and increasing in the late period. The available selenium content in soil significantly affected the selenium uptake by wheat, and there was a significant positive correlation between them. Selenate application significantly increased the grain and leaf biomass of wheat, but other selenium fertilizers had no significant effect on wheat growth. The accumulation capacity of different exogenous selenium fertilizers for wheat followed the order of selenate>selenite, EDTA-chelated selenium>selenium powder, fly ash, and selenium-enriched straw. There was no significant difference between the selenium powder, fly ash, and selenium-enriched straw treatments and the CK treatment. Selenium was more easily transferred to and accumulated in the stems and leaves of wheat after the application of selenate, whereas selenium was more easily transferred to and accumulated in grains after the application of selenite and EDTA-chelated selenium.

Differential responses of soil nematode community to pig manure application levels in Ferric Acrisols.

Excessive pig manure application probably degrades arable soil quality in some intensive pig farming areas. The responses of the nematode community to dosages of pig manure were investigated in Ferric Acrisols under 3-season peanut monoculture. Varying dosages of manure (1.75, 3.5, 7, 14 and 28 t·ha-1·yr-1) in combination with chemical fertilizer were applied to field plots, and chemical fertilizer alone was also applied as a control. With increasing manure application, the abundance of bacterivores and omnivores-predators increased, the abundance of plant parasites decreased, and fungivores abundance exhibited hump-shaped variation. Simpson diversity index and plant parasite index/maturity index of the nematode communities increased to a maximum level at a manure application rate of 3.5 t·ha-1·yr-1 and then sharply decreased. The changes in the soil nematode community were further determined to be correlated with chemical properties; available phosphorus had the strongest quadratic correlation with the two indices, implying that available phosphorus had a better indicative effect than other soil properties to nematode community. Available phosphorus in soil was deduced from 49 to 64 mg·kg-1 with the best nematode communities. Our results emphasized the importance of regular applications of manure in agriculture field to balance nematode diversity and build healthy agro-ecosystems.

Protective effects of tanshinone â ¡A on endothelial progenitor cells injured by tumor necrosis factor-α.

Tanshinone ⅡA (Tan ⅡA) is a Traditional Chinese Medicine commonly used in Asian and Western countries for the prevention and treatment of cardiovascular disorders, such as atherosclerosis. Endothelial dysfunction and associated inflammatory processes have a critical role in the development of atherosclerosis. Endothelial progenitor cells (EPCs) have been demonstrated to be involved in certain aspects of the endothelial repair process. The present study aimed to investigate the putative protective effects of Tan ⅡA on EPCs injured by tumor necrosis factor­α (TNF­α). The potential effects of Tan ⅡA on TNF-α-stimulated EPC proliferation, migration, adhesion, in vitro tube formation ability and paracrine activity were investigated in the current study. The results indicated that TNF­α impaired EPC proliferation, migration, adhesion capacity and vasculogenesis ability in vitro as well as promoted EPC secretion of inflammatory cytokines, including monocyte chemoattractant protein­1 (MCP­1), interleukin­6 (IL­6) and soluble CD40 ligand (sCD40L). However, Tan ⅡA was able to reverse these effects. In conclusion, these findings demonstrated that Tan ⅡA may have the potential to protect EPCs against damage induced by TNF­α. Therefore, these results may provide evidence for the pharmacological basis of Tan ⅡA and its potential use in the prevention and treatment of early atherosclerosis associated with EPC and endothelial damage.

Resveratrol attenuates adenosine diphosphate-induced platelet activation by reducing protein kinase C activity.

Inappropriate platelet activation is the key point of thrombogenesis. The aim of the present study was to investigate the effects of resveratrol (RESV), a compound extracted from the Chinese medicinal herb Polygonum cuspidatum sieb et Zucc, on the platelet activation induced by adenosine diphosphate (ADP) and its possible mechanism. The percentage of platelet aggregation and surface P-selectin-positive platelets, and the activity of protein kinase C (PKC) of platelet were observed with platelet aggregometer, flow cytometry and phosphorimaging system, respectively. RESV at 25, 50 and 100 microM showed anti-platelet aggregation and inhibition of surface P-selectin-positive platelets in a concentration-dependent manner. RESV (50 microM) inhibited the activity of PKC in the membrane fraction of platelets and decreased the percentage of membrane associated PKC activity in total PKC activity. Moreover, DL-erythro-1,3-Dihydroxy-2-aminooctadecane, an elective protein kinase C inhibitor (PKCI), and RESV had additive effects of inhibiting the percentage of platelet aggregation and surface P-selectin-positive platelets. It is suggested that RESV may inhibit platelet aggregation, the percentage of surface P-selectin-positive platelets and subsequent thrombus formation. The mechanisms may be partly relative to the decrease of the activity of PKC of platelets.

[Inhibitory effect of resveratrol on cardiac fibroblast proliferation induced by angiotensin II].

OBJECTIVE: To observe the effect and mechanism of resveratrol on cardiac fibroblast (cFs) proliferation induced by angiotensin II (Ang II). METHODS: The in vitro cFs proliferation model was established by stimulating cultured cFs of new born rats with Ang II by differential attachment method. Cell proliferation was measured by MTT assay, and the effect of resveratrol, L-NAME and ODQ on cell proliferation were observed respectively. Besides, the hypertrophic response of cFs was estimated by measuring expressions of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) mRNA, with the levels of ANP and BNP in culture medium determined by radioimmunoassay and ELISA respectively; and their mRNA expressions determined by reverse transcription polymerase chain reaction (RT-PCR). Level of nitric oxide (NO) in the culture medium was measured by Griess reagent; nitric oxide synthase (NOS) level by chemical colorimetric method; and cGMP by radioimmunoassay. RESULTS: Resveratrol at the dose of 25-100 micromol/L inhibited cFs proliferation in a time and dose dependent manner, which could be partially blocked by pretreatment with L-NAME or ODQ. NO and cGMP levels increased, ANP, BNP levels and their mRNA expression lowered after resveratrol treatment. CONCLUSION: Resveratrol in a definite concentration range could inhibit cFs proliferation and hypertrophic response induced by Ang II, up-regulating the signal pathway of NO and cGMP might be one of the acting paths of the inhibitory effects.

[Inhibitory effects of emodin on proliferation of rat vascular smooth muscle cell induced by angiotensin II].

OBJECTIVE: To investigate the effects of emodin on the proliferation of cultured rat vascular smooth muscle cell (VSMC) induced by angiotensin II. METHOD: VSMCs were cultured by explant method. Cell proliferation model was established by stimulation with Ang II. Cell proliferation was measured by MTT assay to observe the effects of emodin (10, 20, 40 and 80 micromol x L(-1)) and N(G)-nitro-L-arginine methyl ester (L-NAME, 100 micromol x L(-1)) on VSMC proliferation induced by Ang II. The expression of PCNA was measured by immunohistochemical staining. Nitric oxide (NO) level was measured by Griess reagent. Nitric oxide synthase (NOS) and inducible nitric oxide synthase (iNOS) levels were detected by chemical colorimetric method. mRNA expression of iNOS was measured by reverse transcription polymerase chain reaction (RT-PCR). RESULT: Emodin at the doses range from 10 to 80 mol x L(-1) inhibited cell proliferation in a dose and time-dependent manner. The inhibitory effects were partly blocked by 100 mol x L(-1) of L-NAME. Emodin markedly decreased the expression of PCNA in VSMC, increased NO, NOS and iNOS levels, and increased iNOS mRNA expression in VSMC. CONCLUSION: Emodin could inhibite VSMCs proliferation induced by Ang II. Inhibiting the expression of PCNA, increasing the NO secretion and upregulating the iNOS gene expression might be associated with the inhibitory effects.

[Effects of intercropping peanut with medicinal plants on soil microbial community].

With pot experiment, this paper studied the quantitative variations of bacteria, actinomyces, mould and yeast in soils of peanut intercropped with medicinal plants, aimed to test if such an intercropping pattern could remove the obstacles of peanut's continuous cropping. The results showed that Atractylodes lancea and Euphorbia pekinensis had the strongest inhibitory effect on mould. Compared with CK (mono-cropping peanut), the CFU of mould in the treatments intercropped with A. lancea and E. pekinensis was decreased by 53.87% and 29.59%, respectively during flowering-pegging stage of peanut, but increased after harvesting, which was in favor of substance circulation and nutrient returning. The CFU of bacteria in treatments intercropped with A. lancea, E. pekinensis and Pinellia ternate was all increased, and that of yeast in all five intercropping treatments was increased during the flowering-pegging stage of peanut. No familiar pathogens were found in the treatments intercropped with A. lancea, E. pekinensis and Diosoren zingiberebsis. Peanut intercropped with medicinal plants could regulate soil microbial community effectively.

[Effects of Ginkgo biloba extract on number and activity of endothelial progenitor cells from peripheral blood].

AIM: To investigate whether Ginkgo biloba extract can augment endothelial progenitor cell (EPC) number, and promote EPC proliferation, migration and adhesion. METHODS: Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. After 7 days of culture, attached cells were stimulated with Ginkgo biloba extract (10, 25 and 50 mg x L(-1)) or vehicle control for the respective time points (6, 12, 24 and 48 h). EPC were characterized as adherent cells double positive for DiLDL-uptake and lectin binding by direct fluorescent staining under a laser scanning confocal microscope. EPC were further documented by demonstrating the expression of CD34, VEGFR-2 and AC133 with flow cytometry. EPC proliferation, migration and in vitro vasculogenesis activity were assayed with MTT assay, modified Boyden chamber assay and in vitro vasculogenesis kit, respectively. EPCs adhesion assay was performed by replating MNCs on fibronectin-coated dishes, and then counting adherent cells. RESULTS: Incubation of isolated human MNCs with Ginkgo biloba extract increased the number of EPC, maximum at 25 mg x L(-1), 24 hours (approximately 1-fold increase, P < 0.01). In addition, Ginkgo biloba extract promotes EPC proliferative, migratory, adhesive and in vitro vasculogenesis capacity. CONCLUSION: Ginkgo biloba may promote EPC augmentation and enhance its functional activity.

[Effects of puerarin on number and activity of endothelial progenitor cells from peripheral blood].

OBJECTIVE: To investigate whether puerarin can augment endothelial progenitor cells (EPCs) numbers, promote EPC proliferation, migration and adhesion. METHOD: Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. After 7 days culture, attached cells were stimulated with puerarin (to make a series of final concentrations: 0. 1, 0.5, 1, 3 mmol x L(-1)) or vehicle control for the respective time points (6, 12, 24, 48 h). EPCs were characterized as adherent cells double positive for DiLDL-uptake and lectin binding by direct fluorescent staining under a laser scanning confocal microscope. EPCs proliferation, migration and in vitro vasculogenesis activity were assayed with MT assay, modified Boyden chamber assay and in vitro vasculogenesis kit, respectively. EPCs adhesion assay was performed by replating those on fibronectin-coated dishes, then adherent cells were counted. RESULT: Incubation of isolated human MNCs with puerarin dose increased the number of EPCs, maximum at 3 mmol x L(-1), 24 hours (approximately 1-fold increase, P < 0.01). In addition, puerarin also promoted EPC proliferative, migratory, adhesive and in vitro vasculogenesis capacity. CONCLUSION: Puerarin can augment the number of EPCs with enhanced functional activity.

[Effect of tetradrine on electrophysilogic changes caused by rising of left ventricular preload in guinea pigs].

OBJECTIVE: To investigate the changes of guinea pig heart electrophysiological properties caused by increasing left ventricular preload, and to assess the effects of tetradrine on these changes. METHOD: Working model preparation of guinea pig hearts in vitro was used, and the preload of left ventricle was increased by adjusting the prefusion pressure of left atria. The changes of heart electrophysiologic parameters including monophasic action potential duration (MAPD90), monophasic action potential amplitude (MAPA), effective refractory period (ERP) and ventricular fibrillation threshold (VFT) were observed before and after altering the preload of left ventricle, and compared in the absence and presence of tetradrine, streptomycin or verapamil. RESULT: The rising of left ventricular preload led to shortening of MAPD90, ERP, and to descent of MAPA, VFT (all P<0.01). Both Tetradrine and streptomycin inhibited these changes of heart electrophysiologic parameters caused by elevation of left ventricular afterload (all P<0.01). In contrast, verapamil had no effects on the preload-related electrophysiological changes (all P>0.05). CONCLUSION: Electrophysiologic changes caused by increasing left ventricular preload may be inhibited by tetrandrine, through inhibition of stretch-activated ion channels.