Phytophthora sojae effector PsAvh113 associates with the soybean transcription factor GmDPB to inhibit catalase-mediated immunity.

Phytophthora species are the most destructive plant pathogens worldwide and the main threat to agricultural and natural ecosystems; however, their pathogenic mechanism remains largely unknown. Here, we show that Avh113 effector is required for the virulence of Phytophthora sojae and is important for development of Phytophthora root and stem rot (PRSR) in soybean (Glycine max). Ectopic expression of PsAvh113 enhanced viral and Phytophthora infection in Nicotiana benthamiana. PsAvh113 directly associated with the soybean transcription factor GmDPB, inducing its degradation by the 26S proteasome. The internal repeat 2 (IR2) motif of PsAvh113 was important for its virulence and interaction with GmDPB, while silencing and overexpression of GmDPB in soybean hairy roots altered the resistance to P. sojae. Upon binding to GmDPB, PsAvh113 decreased the transcription of the downstream gene GmCAT1, which acts as a positive regulator of plant immunity. Furthermore, we revealed that PsAvh113 suppressed the GmCAT1-induced cell death by associating with GmDPB, thereby enhancing plant susceptibility to Phytophthora. Together, our findings reveal a vital role of PsAvh113 in inducing PRSR in soybean and offer a novel insight into the interplay between defence and counter-defence during the P. sojae infection of soybean.

Effects of 1.5 and 4.3 GHz microwave radiation on cognitive function and hippocampal tissue structure in Wistar rats.

Previous studies have shown that single-frequency microwave radiation can lead to cognitive decline in rats. However, few studies have focused on the combined effects of irradiation with different frequencies of microwaves. Our research aimed to investigate the effects of 1.5 GHz and 4.3 GHz microwave radiation, singly and in combination, on cognitive function and hippocampal tissue structure in rats. A total of 140 male Wistar rats were randomly divided into 4 groups: the S group (sham radiation group), L10 group (10 mW/cm2 1.5 GHz group), C10 group (10 mW/cm2 4.3 GHz band group) and LC10 group (10 mW/cm2 1.5 and 4.3 GHz multi-frequency radiation group). For 1-28 days after microwave radiation, we analyzed the average escape latency for the Morris water maze task, electroencephalograms, change in hippocampal tissue structure and ultrastructure, content of the Nissl body in the hippocampus, and activities of lactate dehydrogenase and succinate dehydrogenase. Compared to the S group, all exposure groups showed varying degrees of learning and memory decline and hippocampal structural damage. The results showed that 1.5 GHz and 4.3 GHz microwave radiation was able to induce cognitive impairment and hippocampal tissue damage in rats and combined radiation with both frequencies caused more serious injuries, but none of these damaging effects varied with microwave frequency.

[Study on estrogenic effect of genistein and apigenin in vitro].

OBJECTIVE: To detect the estrogenic activity of genistein and apigenin with ER-positive cell line MCF-7 human breast cancer cells. METHOD: MTT method was adopted to study the impact of genistein and apigenin on MCF-7 proliferation in vitro. Real-time RT-PCR method was used to detect their impact on ERalpha, ERbeta, PR and PS2 mRNA expression levels. RESULT: Genistein and apigenin promoted the proliferation of MCF-7. Genistein 1 x 10(-10) mol x L(-1) group showed a significant increase in the expression of ERa mRNA levels or a 17. 76 times more than the control group and a 1.75 times more than the E2 group. Apigenin notably promoted the PR mRNA expression or a 4. 57 times more than the control group and a 1.11 times more than the E2 group. Both of them had different effect in promoting ERalpha, ERbeta, PR or PS2 mRNA. CONCLUSION: Both genistein and apigenin have a strong estrogen-like effect. Although they have different effect in promoting estrogenic response genes (such as ERa, ERbeta, PR and PS2 mRNA), genistein shows a stronger activity than apigenin. It also suggests that the signaling pathways of phytoestrogens showing estrogen-like effect are not completely identical with estrogen pathways. The B-cycle position of flavonoids is one of the key sites to estrogen-like activity, and isoflavones (cycle B on site 3) show stronger estrogen-like activity than flavones (B-cycle lies in site 2).

[Effect of osthol on apoptosis and bone resorption of osteoclasts cultured in vitro].

This study is to investigate the effect of osthol on osteoclasts' activity, bone resorption as well as apoptosis in vitro, and explore the mechanism of osthol in preventing osteoporosis. Osteoclasts were separated from long-limb bones of new born rabbits, cultured in 24-well plate with glass slices and bone slices, and treated by 1 x 10(-5) mol x L(-1) osthol. Osteoclasts were identified by observing live cells with phase contrast microscope, HE staining, TRAP staining and toluidine blue staining of bone resorption pits. The numbers of bone resorption pits were counted as well as the surface area of bone resorption on bone slice. Osteoclasts were stained with acridine orange to detect the cell apoptosis. The ratio of apoptotic osteoclasts was observed under fluorescence microscope. The gene expression of RANKL, OPG, TRAP and p-JNK1/2 protein expression were examined using real time PCR and Western blotting, respectively. Comparing with the control group without osthol, the rates of apoptotic osteoclasts increased obviously and the number and area of bone resorption pits decreased evidently with 1 x 10(-5) mol x L(-1) osthol. There is significant difference between control group and experiment group treated by 1 x 10(-5) mol x L(-1) osthol. Therefore, the osthol through RANK+RANKL/TRAF6/Mkk/JNK signal pathway inhibits the osteoclasts activity, enhances osteoclasts apoptotic and inhibits the bone resorption.

[Effects of icariin on the proliferation, differentiation and maturation of rat calvarial osteoblasts in vitro].

OBJECTIVE: To investigate the effects of icariin on the proliferation, differentiation and maturation of rat calvarial osteoblasts (ROB). METHODS: Segregated neonatal SD rat skull,enzyme digestion to obtain ROB. The culture medium was replaced every three days. Serial subcultivation proceeded when cells covered with 80% culture dish. Icariin was added into the culture at 1 x 10(-4), 1 x 10(-5), 1 x 10(-6), 1 x 10(-7) mol/L respectively. MTT method was adopted in proliferation analysis. The activity of ALP was assayed after 9 days' induced. Optimal concentration icariin was added into the medium, then the osteogenic differentiation markers including mineralized bone nodules, CFU-F(ALP) were compared between the icariin-added group and the control. Total RNA was isolated and the gene expressions of Runx-2 and Osterix were investigated by Real Time RT-PCR. Total protein was also isolated and the secretion of collagen I was examined by Western-blot. RESULTS: The ROB proliferation was inhibited by icariin in a dose-dependent manner. But it evidently led to osteogenic process and maturation. 1 x 10(-5) mol/L was the best concentration. Icariin improved the secretion of collagen I, CFU-F(ALP) amounts and mineralized nodules significantly. It also enhanced the mRNA level of Runx-2 and Osterix. CONCLUSION: The icariin with final concentration of 1 x 10(-5) mol/L can enhance the osteogenic differentiation and maturation of ROB significantly, suggesting that icariin has the activity of inducing bone formation, it has the potential to be developed into a new drug of anti-osteoporosis.

Effects of 50 Hz sinusoidal electromagnetic fields of different intensities on proliferation, differentiation and mineralization potentials of rat osteoblasts.

Electromagnetic fields (EMFs) have been used clinically to slow down osteoporosis and promote fracture healing for many years. However, the underlying action mechanisms and optimal parameters of the EMF applications are unclear. In this study, we investigated the effects of treatment for different durations with 50 Hz sinusoidal electromagnetic fields (SEMFs) at different intensities on proliferation, differentiation and mineralization potentials of rat osteoblasts. Osteoblasts isolated from neonatal rats were treated with SEMFs (50 Hz at 0.9 mT-4.8 mT, 0.3 mT interval, 30 min/day up to 15 days). Compared to untreated control, SEMFs inhibited osteoblast proliferation (after 3 days' treatment) but increased alkaline phosphatase (ALP) activity (after treatment for 9 days) from 0.9 mT to 1.8 mT, declined from 1.8 mT until 3.0 mT, and then increased again from 3.0 mT to 3.6 mT and decreased once again from 3.6 mT to 4.8 mT. Numbers of colonies stained positive for ALP after 8 days and mineralized nodules stained by Alizarin red after 10 days showed the same bimodal tendency as with the ALP activity, with two peaks at 1.8 mT and 3.6 mT. SEMFs also bimodally increased Runx-2, Col1α2 and Bmp-2 mRNA expression levels in osteoblasts at 12, 24 and 96 h after exposure. The results indicated that while exposure to 50 Hz SEMFs inhibits the osteoblast proliferation, it significantly promotes differentiation and mineralization potentials of osteoblasts in an intensity-dependent manner with peak activity at 1.8 mT and 3.6 mT.