[Effects of Biochar and Straw Returning on Soil Fungal Community Structure Diversity in Cotton Field with Long-term Brackish Water Irrigation].

Brackish water irrigation increases soil salinity and changes the soil environment, which affects the structure and diversity of soil fungi. In this study, the effects of biochar and straw (3.7 t·hm-2 and 6 t·hm-2, respectively) on soil physical and chemical properties and fungal community structure diversity were investigated on the basis of long-term brackish water irrigation. The results showed that compared to the absence of biochar and straw application (control), biochar application significantly increased pH and the contents of total carbon, available potassium, and available phosphorus in soil but significantly decreased the soil conductivity by 20.71%. Straw treatment significantly increased the content of available potassium and phosphorus but significantly decreased the soil bulk density and conductivity by 4.17% and 64.50%, respectively. The biochar and straw treatment showed an increasing trend in the Chao1 index and ACE index of the fungal community but a decreasing trend in the Shannon index and Simpson index. The dominant fungal phyla in the soil were Ascomycota, Mortierellomycota, Basidiomycota, Chytridiomycota, and Glomeromycota. The dominant fungal genera were Chaetomium, Gibberella, Fusarium, Idriella, and Mortierella. Biochar and straw were applied to increase the relative abundance of Ascomycota, Mortierellomycota, Basidiomycota, Glomeromycota, and Chaetomium. However, the relative abundance of Chytridomycota, Gibberella, and Idriella decreased. LEfSe analysis showed that biochar application and straw returning decreased the number of potential biomarkers in fungal communities. RDA results showed that soil fungal community structure was significantly correlated with EC1:5 and TN. Brackish irrigation had adverse effects on soil, in which EC1:5and TN were the main factors driving the change in soil fungal community structure. The soil fungal community adapted to a salt-stress environment through the improvement of soil by biochar and straw.

Rituximab inhibits Kv1.3 channels in human B lymphoma cells via activation of FcγRIIB receptors.

Kv1.3 channels play an important role in modulating lymphocyte proliferation and apoptosis. We hypothesized that Kv1.3 channels in B lymphocytes might be regulated by rituximab, an antibody to CD20, a drug for treatments of B-cell lymphomas and autoimmune diseases. Using both whole-cell and cell-attached patch-clamp techniques, we found that rituximab inhibited Kv1.3 channels in Daudi human B lymphoma cells by promoting the channel inactivation at a concentration which was much greater than that required for activation of CD20. The effect of rituximab on Kv1.3 channels was abolished after selective blockade of FcγRIIB receptors with anti-FcγRIIB antibody. Western blot experiments showed that Daudi B cells expressed both Kv1.3 channel and the low affinity Fc receptor, FcγRIIB, which could be activated by the Fc region of rituximab. In contrast, normal lymphocytes expressed less Kv1.3 channels with faster inactivation. Confocal microscopy and flow cytometry data showed that rituximab induced apoptosis of Daudi B cells and that the effect was attenuated by blockade of FcγRIIB receptors and partially mimicked by inhibition of Kv1.3 channels. These results suggest that in addition to previously described complement-dependent cytotoxicity, rituximab also induces apoptosis of malignant B lymphocyte by stimulating FcγRIIB receptors and inhibiting Kv1.3 channels.

Dispersive solid-phase extraction cleanup combined with accelerated solvent extraction for the determination of carbamate pesticide residues in Radix Glycyrrhizae samples by UPLC-MS-MS.

Dispersive solid-phase extraction (DSPE) cleanup combined with accelerated solvent extraction (ASE) is described here as a new approach for the extraction of carbamate pesticides in Radix Glycyrrhizae samples prior to UPLC-MS-MS. In the DSPE-ASE method, 15 carbamate pesticides were extracted from Radix Glycyrrhizae samples with acetonitrile by the ASE method at 60 °C with a 5 min heating time and two static cycles. Cleanup of a 1 mL aliquot of the extract by the DSPE method used 20 mg PSA (primary secondary amine), 50 mg Al(2)O(3)-N, and 20 mg GCB (graphitized carbon black) (as cleanup sorbents) under the determined optimum conditions. The linearity of the method was in the range of 10 to 200 ng/mL with correlation coefficients (r(2)) of more than 0.996. The limits of detection were approximately 0.2 to 5.0 µg/kg. The method was successfully used for the analysis of target pesticides in Radix Glycyrrhizae samples. The recoveries of the carbamate pesticides at the spiking levels of 50, 100, and 200 µg/kg ranged from 79.7% to 99.3% with relative standard deviations lower than 10%. This multi-residue analytical method allows for a rapid, efficient, sensitive and reliable determination of target pesticides in Radix Glycyrrhizae and other medicinal herbs.

The anti-tumor effects of alkaloids from the seeds of Strychnos nux-vomica on HepG2 cells and its possible mechanism.

To screen the anti-tumor effects of the four alkaloids: brucine, strychnine, brucine N-oxide and isostrychnine from the seed of Strychnos nux-vomica, MTT assay was used to examine the growth inhibitory effects of these alkaloids on human hepatoma cell line (HepG2). Brucine, strychnine and isostrychnine revealed significant inhibitory effects against HepG2 cell proliferation, whereas brucine N-oxide didn't have such an effect. In addition, brucine caused HepG2 cell shrinkage, membrane blebbing, apoptotic body formation, all of which are typical characteristics of apoptotic programmed cell death. The results of flow cytometric analysis demonstrated that brucine caused dose-dependent apoptosis of HepG2 cells through cell cycle arrest at G0/G1 phase, thus preventing cells entering S or G2/M phase. Immunoblot results revealed that brucine significantly decreased the protein expression level of cyclooxygenase-2, whereas increased the expression caspase-3 as well as the caspase-3-like protease activity in HepG2 cells, suggesting the involvement of cyclooxygenase-2 and caspase-3 in the pro-apoptotic effects exerted by brucine. Therefore, this paper indicate that the major alkaloids present in the seed of Strychnos nux-vomica are effective against HepG2 cells proliferation, among which brucine proceed HepG2 cells death via apoptosis, probably through the participation of caspase-3 and cyclooxygenase-2.