Effects of maize rotation on the physicochemical properties and microbial communities of American ginseng cultivated soil.

The production of American ginseng (Panax quinquefolius L.) is severely limited by the replant disorders in China. Crop rotation with maize might reduce the replant problems, but little information is available on the effect of maize rotation on soil cultivated with ginseng. In this study, we analyzed nutrients, phenolic acids, and microbial communities in soils from the fields with continuous maize, mono-culture ginseng, and 1-, 3-, and 5-year maize rotation after ginseng. Pot experiments were also conducted to evaluate the performance of replanting ginseng in these soils. The results showed that Mn, Cu, and 5 phenolic acids in ginseng-cultivated soil were significantly decreased by maize rotation. A 5-year maize rotation significantly increased the relative abundance of beneficial soil bacteria, such as Arthrobacter, rather than decreasing the abundances of potential pathogenic genera. Clustering analysis revealed that the physicochemical properties and microbial communities of 3- and 5-year maize rotation soil were more similar to CM than to G soil. The biomass of replanted ginseng root was improved, and root disease was reduced over 3 years of maize rotation. Overall, the results showed that at least a 3-year maize rotation is needed to overcome the replant failure of American ginseng.

Lycium Barbarum Polysaccharides Improve Retinopathy in Diabetic Sprague-Dawley Rats.

Diabetic retinopathy (DR) has become the most frequent cause of impaired visual acuity and blindness in working-age population in developed countries. Here we use diabetic rats to clarify the role of Lycium barbarum polysaccharides (LBP) on DR. We treated diabetic rats with LBP (400 mg/kg/d or 200 mg/kg/d) orally for 20 weeks. Electroretinogram (ERGs) and Laser Doppler blood flow were measured to assess the retinal function, routine histology and ultrastructural studies were performed to evaluate the morphological alterations, and immunohistochemistry, western blotting, and RT-PCR were conducted to detect the protein and mRNA levels of pro- and antiangiogenic factors. The results showed that diabetes suppressed the amplitudes of a-wave, b-wave, and oscillatory potential in ERG, reduced retinal blood flow, decreased the thickness of the retina, and increased the thickness of basement membrane of the retinal capillary. Furthermore, diabetes increased the mRNA and protein expressions of proangiogenic GFAP and VEGF and suppressed the levels of antiangiogenic PEDG. Treatment with LBP either completely or partially reversed the alterations caused by diabetes. It is concluded that the LBP protects retinal function and morphology in diabetic rats, probably through reinstallation of the balance between proangiogenic and antiangiogenic factors, which reduces neovascularization. LBP could be used as a therapeutic drug for DR.

Lycium barbarum polysaccharide attenuates high-fat diet-induced hepatic steatosis by up-regulating SIRT1 expression and deacetylase activity.

In this study, we aimed to investigate the protective effects and underlying mechanism of Lycium barbarum polysaccharide (LBP) on high-fat-induced nonalcoholic fatty liver disease (NAFLD). Recently, sirtuin 1 (SIRT1) has been shown to play an important role in the regulation of hepatocellular lipid metabolism. Here, we demonstrated that LBP up-regulates SIRT1 deacetylase activity and protein expression by enhancing the NAD+/NADH ratio. Subsequently, LBP promoted LKB1 deacetylation and AMPK phosphorylation via SIRT1-dependent signalling. We also found that LBP increases acetyl-CoA carboxylase (ACC) phosphorylation and adipose triglyceride lipase (ATGL) protein expression and decreases fatty acid synthase (FAS) by activating the SIRT1/LKB1/AMPK pathway in vitro and in vivo. However, SIRT1 small interfering RNA (siRNA)-mediated knockdown reversed the LBP-mediated effects on ACC, FAS and ATGL. Moreover, LBP elevated carnitine palmitoyltransferase-1 alpha (CPT-1α) expression by suppressing malonyl-CoA accumulation. Taken together, our data indicate that LBP plays a vital role in the regulation of hepatic lipid metabolism and that pharmacological activation of SIRT1 by LBP may be a strategy for the prevention of NAFLD.

TP53 mutant MDM2-amplified cell lines selected for resistance to MDM2-p53 binding antagonists retain sensitivity to ionizing radiation.

Non-genotoxic reactivation of the p53 pathway by MDM2-p53 binding antagonists is an attractive treatment strategy for wild-type TP53 cancers. To determine how resistance to MDM2/p53 binding antagonists might develop, SJSA-1 and NGP cells were exposed to growth inhibitory concentrations of chemically distinct MDM2 inhibitors, Nutlin-3 and MI-63, and clonal resistant cell lines generated. The p53 mediated responses of parental and resistant cell lines were compared. In contrast to the parental cell lines, p53 activation by Nutlin-3, MI-63 or ionizing radiation was not observed in either the SJSA-1 or the NGP derived cell lines. An identical TP53 mutation was subsequently identified in both of the SJSA-1 resistant lines, whilst one out of three identified mutations was common to both NGP derived lines. Mutation specific PCR revealed these mutations were present in parental SJSA-1 and NGP cell populations at a low frequency. Despite cross-resistance to a broad panel of MDM2/p53 binding antagonists, these MDM2-amplified and TP53 mutant cell lines remained sensitive to ionizing radiation (IR). These results indicate that MDM2/p53 binding antagonists will select for p53 mutations present in tumours at a low frequency at diagnosis, leading to resistance, but such tumours may nevertheless remain responsive to alternative therapies, including IR.

Mycobiota and Mycotoxins in Traditional Medicinal Seeds from China.

The multi-mycotoxin occurrence for internal and superficial fungi contamination were comprehensively assessed in medicinal seeds used as food or beverage. Based on a polyphasic approach using morphological characters, ß-tubulin and ITS gene blast, a total of 27 species belonging to 12 genera were identified from surface-sterilized seeds. Chaetomium globosporum was most predominant (23%), followed by Microascus trigonosporus (12%) and Alternaria alternata (9%). With respect to superficial mycobiota, thirty-four species belonging to 17 genera were detected. Aspergillus niger and Penicillium polonicum were predominant (12% and 15%, respectively). Medicinal seed samples and potential toxigenic fungi were tested for ochratoxin A (OTA) and aflatoxins (AFB1, AFB2, AFG1, AFG2) using UPLC-MS/MS. Platycladi seeds were contaminated with AFB1 (52.0 µg/kg) and tangerine seed was contaminated with OTA (92.3 µg/kg). Subsequent analysis indicated that one A. flavus strain isolated from platycladi seed was able to synthesize AFB1 (102.0 µg/kg) and AFB2 (15.3 µg/kg). Two P. polonicum strains isolated from tangerine and lychee seeds were able to synthesize OTA (4.1 µg/kg and 14.8 µg/kg, respectively). These results identify potential sources of OTA and aflatoxins in medicinal seeds and allude to the need to establish permitted limits for these mycotoxins in these seeds that are commonly consumed by humans.

Effects of Fusarium solani and F. oxysporum Infection on the Metabolism of Ginsenosides in American Ginseng Roots.

American ginseng (Panax quinquefolius L.) is a highly valuable herb widely used for medicinal treatments. Its pharmacologically important compounds are the ginsenosides, which are secondary metabolites in American ginseng root. The concentrations of ginsenoside in roots can be changed by fungal infection, but it is unclear what specific root tissues are impacted and whether the change is systemic. In this study, American ginseng roots were inoculated with two fungal pathogens (Fusarium solani or F. oxysporum) and the levels of six ginsenosides (Rb1, Rb2, Rc, Rd, Re, and Rg1) were then measured in the phloem and xylem around the discolored lesions and adjacent healthy areas of the root. Results indicated that the growth of Fusarium spp. was strictly limited to phloem, and correspondingly the ginsenoside concentration was only altered in this infected phloem. The concentration of Rg1, Rd, and Rc significantly changed in phloem tissues where F. solani was inoculated, while only Rg1 and Rd changed significantly after F. oxysporum inoculation. However, no changes of any ginsenoside occurred in either xylem or phloem tissue adjacent to the inoculation point. In addition, when two Fusarium spp. were grown on ginsenoside-amended Czapek medium, the majority of ginsenosides were depleted. Therefore, pathogenic Fusarium spp. may reduce ginsenoside levels by consuming them.

Searching for Dual Inhibitors of the MDM2-p53 and MDMX-p53 Protein-Protein Interaction by a Scaffold-Hopping Approach.

Two libraries of substituted benzimidazoles were designed using a 'scaffold-hopping' approach based on reported MDM2-p53 inhibitors. Substituents were chosen following library enumeration and docking into an MDM2 X-ray structure. Benzimidazole libraries were prepared using an efficient solution-phase approach and screened for inhibition of the MDM2-p53 and MDMX-p53 protein-protein interactions. Key examples showed inhibitory activity against both targets.

An independent study of the preclinical efficacy of C2-8 in the R6/2 transgenic mouse model of Huntington's disease.

BACKGROUND: C2-8 is a small molecule inhibitor of polyglutamine aggregation and can reduce photoreceptor neurodegeneration in a Drosophila model of Huntington's disease (HD). Further preclinical studies have shown that oral administration of C2-8 in R6/2 HD transgenic mice can penetrate into the brain, reduce mHTT-exon1 aggregation, improve motor performance and diminish striatal neuron atrophy. OBJECTIVE: In this independent preclinical study, we aimed to evaluate the pharmacokinetic properties and therapeutic efficacy of C2-8 intraperitoneal (IP) delivery in the R6/2 HD mouse. METHODS: R6/2 mice were IP injected with low dose C2-8 (10 mg/kg), high dose C2-8 (20 mg/kg), or vehicle twice daily from 3 weeks to 3 months old. Longitudinal behavioral tests (accelerating Rotarod and wire-hang) were performed to evaluate the motor deficits, and neuropathology was measured by unbiased stereology. RESULTS: We confirmed that the compound has good blood-brain-barrier penetration after acute or sub-chronic intraperitoneal delivery. Chronic treatment with C2-8 in R6/2 mice results in a significant reduction of nuclear mHTT aggregate volume in the brains, replicating a key finding of C2-8 as a polyglutamine aggregation inhibitor in vivo. However, by comparing HD mice with C2-8 treatment to those with vehicle treatment, we were unable to demonstrate significant amelioration of motor deficits using Rotarod and wire-hang tests. Moreover, we did not observe improvement in the striatal neurodegenerative pathology, as measured by brain weight, striatal volume, and striatal neuron volume in the C2-8 treated R6/2 mice. CONCLUSIONS: Our study supports the practice of independent preclinical studies for novel molecules in HD therapeutic development and suggests that the use of alternative delivery strategies and full-length HD mouse models are likely needed to further assess whether the aggregate-inhibiting properties of C2-8 can be consistently translated into a preclinical benefit in HD mice.

[Effects of berberine on expression of hepatocyte nuclear factor 4alpha and glucokinase activity in mouse primary hepatocytes].

OBJECTIVE: To observe the expression of hepatocyte nuclear factor 4alpha (HNF4alpha) and the activity of key enzyme glucokinase (GK) in glucose metabolism, and further to investigate the possible mechanism of berberine in treating type 2 diabetes. METHOD: Mouse primary hepatocytes were isolated by an improved single two-step perfusion method. The murine hepatocytes were cultured and incubated with berberine (0, 1, 3, 10, 30, 100 micromol x L(-1)) and 1 mmol x L(-1) metformin for 24 h respectively. The mRNA expression of HNF4alpha were quantified by RT-PCR and the protein expression of HNF4alpha were quantified by Western-blot. And the activity of GK were detected with enzyme kinetics method. RESULT: As compared with the negative control group, at a certain concentration range, the expression of HNF4alpha mRNA and protein and the activity of GK were promoted by berberine. Both of them reached the top at the concentration of 30 micromol x L(-1) (P<0.01). But the metformin made no difference with the negative control group on the expression of HNF4alpha and the activity of GK. CONCLUSION: It is suggested that the effects of berberine on improving glucose metabolism can be mechanically associated with its up-regulating the HNF4a expression and inducing the activity of hepatic glucokinase.

[Effects of Huanglian Jiedu Decoction on phosphatidylinositol-3-kinase expression in target tissues of type 2 diabetic rats].

OBJECTIVE: To observe the effects of Huanglian Jiedu Decoction (HLJDD), a traditional Chinese compound herbal medicine, on p85 mRNA and protein expressions of phosphatidylinositol-3-kinase (PI-3K) in target tissues (skeletal muscular and adipose tissues) in rats with type 2 diabetes mellitus (T2DM) and to investigate the molecular mechanism of HLJDD in treating T2DM. METHODS: The male Wistar rats were injected with streptozotocin (STZ) 30 mg/kg through tail vein, and fed with high-fat and high-caloric diets to induce T2DM. Then the rats were randomly divided into untreated group, aspirin-treated group and HLJDD group, and treated correspondingly. Meanwhile, a group of normal animals without any treatment was set up for normal control group. Ten weeks later, serum fasting blood glucose (FBG), serum fasting insulin (FINS) and oral glucose tolerance test (OGTT) were routinely determined. The expressions of PI-3K p85 mRNA and protein in skeletal muscle and adipose tissue were determined with RT-PCR and Western blotting before and after insulin treatment. RESULTS: Compared with the untreated group, the FBG and OGTT levels in T2DM rats treated with HLJDD decreased significantly (P<0.05). The FINS in HLJDD group was lower than that in the normal control group (P<0.05), but was not significantly different from that in the untreated group. The PI-3K p85 mRNA and protein expressions in HLJDD group obviously increased, as compared with those in the untreated group. CONCLUSION: The effect of HLJDD in treating T2DM was probably associated with its improvement of PI-3K p85 mRNA and protein expressions in skeletal muscle and adipose tissue of the T2DM rats.