Design, synthesis, and antifungal activity of carboxamide derivatives possessing 1,2,3-triazole as potential succinate dehydrogenase inhibitors.

Succinate dehydrogenase (SDH) is demonstrably one of the most important molecular targets in development of new fungicide. In our continuous efforts to discover novel SDH inhibitors, forty-two carboxamide derivatives containing 1,2,3-triazole ring were designed and synthesized, which were precisely characterized by 1H NMR, ESI-MS, elemental analysis and X-ray single-crystal diffraction. The compounds were screened for antifungal activities against phytopathogenic fungi by mycelia growth inhibition assay in vitro. Compound A3-3 exhibited significant antifungal activity against Sclerotinia sclerotiorum, Botrytis cinerea, Rhizoctonia cerealis and Gaeumannomyces graminsis with EC50 values of 1.08, 8.75, 1.67 and 5.30 µg/mL, respectively, comparable to those of commercial SDHI boscalid. In vivo testing demonstrated that A3-3 was effective for suppressing rape sclerotinia rot, cucumber grey mould and wheat powdery mildew caused by S. sclerotiorum， B. cinerea and Blumeria graminis at a dosage of 200 µg/mL. Inhibition activities against SDH test proved the designed analogues were effective in the enzyme level. The molecular docking simulation revealed that A3-3 interacted with ARG43，TYR58 and TRP173 of the SDH through hydrogen bond and pi-pi interaction, which could explain the probable mechanism of action between the inhibitor and target protein.

New Metabolites from Endophytic Fungus Chaetomium globosum CDW7.

Five metabolites including two new ones, prochaetoviridin A (1) and chaetoindolin A (2), were isolated from the endophytic fungus Chaetomium globosum CDW7. Compounds 1 and 2 were characterized as an isocoumarin and an indole alkaloid derivative, respectively, with their structures elucidated by comprehensive spectroscopic analyses including high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), NMR, and circular dichroism (CD) comparison. Compounds 3⁻5 were identified as chaetoviridin A, chaetoglobosin R, and chaetoglobosin T, respectively. Chaetoviridin A (3) exhibited antifungal activity against Sclerotinia sclerotiorum with an EC50 value of 1.97 µg/mL. In vivo test showed that 3 displayed a protective efficacy of 64.3% against rape Sclerotinia rot at the dosage of 200 µg/mL, comparable to that of carbendazim (69.2%).

Synthesis of 1,2,3-triazole hydrazide derivatives exhibiting anti-phytopathogenic activity.

A series of new 1,2,3-triazole derivatives have been prepared and screened for their antifungal activity against phytopathogenic fungi using the mycelium growth inhibition method in vitro. The results indicated that the 1,2,3-triazole hydrazide scaffold displayed significant antifungal activity. Compound 6ad exhibited the most potent anti-phytopathogenic activity, with EC50 values of 0.18, 0.35, 0.37 and 2.25 µg mL-1 against Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium graminearum, and Magnaporthe oryzae, respectively. In vivo testing demonstrated that 6ad was effective for the control of rice sheath blight, rape sclerotinia rot, fusarium head blight and rice blast caused by the aforementioned phytopathogens. This work suggests that the combination of 1,2,3-triazole and hydrazide moiety could be a promising fungicide scaffold in the future.

Chaetomium globosum CDW7, a potential biological control strain and its antifungal metabolites.

Screening for endophytic fungi with antifungal activity is an effective strategy for the discovery of novel biopesticides. Our previous work indicated that Chaetomium globosum CDW7, an endophyte from Ginkgo biloba, exhibited strong inhibitory activity against plant pathogenic fungi in vitro. In this study, we evaluated the CDW7 strain for its antifungal activities against nine phytopathogenic fungi and its biocontrol potential against rape sclerotinia rot caused by Sclerotinia sclerotiorum. The fermentation broth of CDW7 could successfully inhibit disease development in S. sclerotiorum-infected rape in vivo with 57.8% protective efficiency, which is comparable to that of carbendazim (59.8%) at 250 µg mL-1. The fermentation broth also expressed significant activity stability when exposed to 60°C and UV illumination, or when stored at 4°C. Furthermore, we found that 10% fermentation broth can promote the germination and growth of rape seedlings. Followed by the bioassay-guided approach, seven known metabolites were isolated and identified by spectroscopic analyses. Among them, chaetoglobosin A and D exhibited inhibitory activity against S. sclerotiorum with IC50 values of 0.35 and 0.62 µg mL-1, respectively, compared with carbendazim (0.17 µg mL-1). Therefore, our study demonstrated that CDW7 is a promising biocontrol fungus against S. sclerotiorum in agriculture.

Synthesis and Biological Evaluation of Benzimidazole Phenylhydrazone Derivatives as Antifungal Agents against Phytopathogenic Fungi.

A series of benzimidazole phenylhydrazone derivatives (6a-6ai) were synthesized and characterized by ¹H-NMR, ESI-MS, and elemental analysis. The structure of 6b was further confirmed by single crystal X-ray diffraction as (E)-configuration. All the compounds were screened for antifungal activity against Rhizoctonia solani and Magnaporthe oryzae employing a mycelium growth rate method. Compound 6f exhibited significant inhibitory activity against R. solani and M. oryzae with the EC50 values of 1.20 and 1.85 µg/mL, respectively. In vivo testing demonstrated that 6f could effectively control the development of rice sheath blight (RSB) and rice blast (RB) caused by the above two phytopathogens. This work indicated that the compound 6f with a benzimidazole phenylhydrazone scaffold could be considered as a leading structure for the development of novel fungicides.

Anti-phytopathogenic activity of sporothriolide, a metabolite from endophyte Nodulisporium sp. A21 in Ginkgo biloba.

Phytopathogenic fungi such as Rhizoctonia solani and Sclerotinia sclerotiorum caused multiple plant diseases resulting in severe loss of crop production. Increasing documents endorsed that endophytes are a striking resource pool for numerous metabolites with various bioactivities such as anti-fungal. Here we reported the characterization and anti-phytopathogenic activity of sporothriolide, a metabolite produced by Nodulisporium sp. A21-an endophytic fungus in the leaves of Ginkgo biloba. Among the total twenty-five endophytic fungi isolated from the healthy leaves of G. biloba, the fermentation broth (FB) of the strain A21 was found potently inhibitory activity against R. solani and S. sclerotiorum using mycelia growth inhibition method. A21 was then identified as Nodulisporium sp., the asexual stage of Hypoxylon sp., by microscopic examination and ITS rDNA sequence data comparison. Under the bioassay-guided fractionation, sporothriolide was isolated from the petroleum ether extract of the FB of A21, whose structure was established by integrated interpretation of HR-ESI-MS and (1)H- and (13)C-NMR. Furthermore, the crystal structure of sporothriolide was first reported. In addition, sporothriolide was validated to be potently antifungal against R. solani, S. sclerotiorum and inhibit conidium germination of Magnaporthe oryzae in vitro and in vivo, indicating that it could be used as a lead compound for new fungicide development.

[Expression of miR-140-5p and prediction of its target gene in human mesenchymal stem cells during adipogenic differentiation].

OBJECTIVE: To screen the differentially expressed miRNAs and their target genes in adipogenic differentiation of human bone marrow mesenchymal stem cells (hMSCs) to better understand the mechanism for regulating the balance between osteoblast and adipocyte differentiation. METHODS: Cultured hMSCs were induced for adipogenic differentiation, and at 0, 7, 14, and 21 days of induction, the cells were examined for miRNA and mRNA expression profiles using miRNA chip and transcriptome sequencing (RNA-seq) techniques. Correlation analysis was carried out for the miRNAs and mRNAs of potential interest. The databases including TargetScan, PicTar and miRanda were used to predict the target genes of the differentially expressed miRNA. RESULTS: The expression of miR-140-5p was down-regulated and leukemia inhibitory factor receptor (LIFR) expression increased progressively during adipogenic differentiation of hMSCs, showing a negative correlation between them. Target gene prediction using the 3 databases identified LIFR as the target gene of miR-140-5p. CONCLUSION: miRNA-140-5p may play an important role by regulating its target gene LIFR during adipogenic differentiation of hMSCs.

Involvement of RbAp48 in erythroid differentiation of murine erythroleukemia cells induced by sodium butyrate.

Normal mammalian terminal erythroid differentiation is a precisely regulated process during which the progenitor cells execute particular programs to form a mature erythrocytic phenotype. In the present study, it was found that RbAp48, a histone-binding protein associated with retinoblastoma protein, was upregulated during terminal erythroid maturation in vivo and in vitro. This indicated that RbAp48, at least in part, participated in the regulation of murine erythropoiesis. Following sodium butyrate (SB) induction, murine erythroleukemia (MEL) cells began to re-enter erythroid differentiation and the ratio of differentiated cells reached ~80% at 72 h. The erythroid maturation-related mRNA expression of α-globin, ß-globin and glycophorin A (GPA) was increased markedly, which indicated that SB induced MEL differentiation. During MEL differentiation, the RbAp48 level showed a 1.5-fold increase at 72 h, and the globin transcription factor (GATA)-1 level was also upregulated in the early stage of differentiation. By contrast, the c-Myc level was gradually downregulated in MEL differentiation. Using an immunofluorescence assay, the results of the study directly showed that the average fluorescence intensity of RbAp48 in each cell reached an almost 1.7-fold increase at 72 and 96 h. This was consistent with the western blot results of RbAp48 during MEL differentiation. In addition, reduced expression of RbAp48 by RNA inference decreased SB-induced MEL differentiation by ~20%, indicating that a high level of RbAp48 was essential for MEL differentiation. Taken together, these results established a functional link between RbAp48 and erythroid differentiation.

Benzofurazan derivatives as antifungal agents against phytopathogenic fungi.

A series of benzofurazan derivatives were prepared and evaluated for their biological activities against four important phytopathogenic fungi, namely, Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium graminearum and Phytophthora capsici, using the mycelium growth inhibition method. The structures of these compounds were characterized by (1)H NMR, (13)C NMR, and HRMS. N-(3-chloro-4-fluorophenyl)-7-nitrobenzo[c][1,2,5]oxadiazol-4-amine (A3) displayed the maximum antifungal activity against R. solani (IC50 = 1.91 µg/mL), which is close to that of the positive control Carbendazim (IC50 = 1.42 µg/mL). For other benzofurazan derivatives with nitro group at R(4) position (A series), 9 out of 30 compounds exhibited high antifungal effect against strain R. solani, with IC50 values less than 5 µg/mL. Most of the derivatives with substituents at R(2) and R(3) positions (B series) displayed moderate growth inhibition against S. sclerotiorum (IC50 < 25 µg/mL). Also, several benzofuran derivatives with nitro group at R(4) position and another conjugated aromatic ring at the R(1) position of the phenyl ring displayed high antifungal capability against strain R. solani. Compounds with substituents at R(2) and R(3) position had moderate efficacy against strain S. sclerotiorum.

Cerebroside C increases tolerance to chilling injury and alters lipid composition in wheat roots.

Chilling tolerance was increased in seed germination and root growth of wheat seedlings grown in media containing 20 µg/mL cerebroside C (CC), isolated from the endophytic Phyllosticta sp. TG78. Seeds treated with 20 µg/mL CC at 4 °C expressed the higher germination rate (77.78%), potential (23.46%), index (3.44) and the shorter germination time (6.19 d); root growth was also significantly improved by 13.76% in length, 13.44% in fresh weight and 6.88% in dry mass compared to controls. During the cultivation process at 4 °C for three days and the followed 24 h at 25 °C, lipid peroxidation, expressed by malondialdehyde (MDA) content and relative membrane permeability (RMP) was significantly reduced in CC-treated roots; activities of lipoxygenase (LOX), phospholipid C (PLC) and phospholipid D (PLD) were inhibited by 13.62-62.26%, 13.54-63.93% and 13.90-61.17%, respectively; unsaturation degree of fatty acids was enhanced through detecting the contents of CC-induced linoleic acid, linolenic acid, palmitic acid and stearic acid using GC-MS; capacities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were individually increased by 7.69-46.06%, 3.37-37.96%, and -7.00-178.07%. These results suggest that increased chilling tolerance may be due, in part, to the reduction of lipid peroxidation and alternation of lipid composition of roots in the presence of CC.

[Protective effect and mechanism of astragaloside IV on oxidative stress injury of mesangial cells].

OBJECTIVE: To study the protective effect of astragaloside IV (AS IV) on H2O2 induced human mesangial cells (HMC), and further explore its molecular mechanism. METHOD: The cultured mesangial cells were divided into 5 groups: the normal control group, the H2O2 model group, the AS IV (12.5, 100 nmol x L(-1)) group and the Tempol (1 x 10(5) nmol x L(-1)) group. The MTT method was used to observe cell viability. Hoechst 33258 staining was used to observe the HMC apoptosis and DHE staining was used to detect the generation of reactive oxygen species (ROS). The flow cytometry was used to detect the changes in cell cycle. Western blot was used to detect the expression of Cyclin D1, CyclinA, p38, and T-p38. RESULT: H2O2 (1 x 10(5), 2 x 10(5), 3 x 10(5), and 4 x 10(5) nmol x L(-1)) could induce HMC oxidative stress injury, with significant decrease in the cell survival rate. AS IV (100 nmol x L(-1)) could significantly inhibit HMC oxidative stress injury induced by H2O2 (3 x 10(5) nmol x L(-1)), increase the survival rate of HMC cells, inhibit cell apoptosis, and decrease intracellular ROS production. AS IV could also increase the expression of Cyclin D1, recover normal cell proliferation, and decrease the expression of p38. CONCLUSION: AS IV can protect H2O2 induced oxidative stress injury in mesangial cells. Its mechanisms may be related to inhibiting the p38/MAPK signaling pathway, increasing the expression of Cyclin D1 and decreasing the intracellular ROS oxidative stress injury.

Dynamic modeling for flow-activated chloride-selective membrane current in vascular endothelial cells.

In this paper, a dynamic model is proposed to quantify the relationship between fluid flow and Cl(-)-selective membrane current in vascular endothelial cells (VECs). It is assumed that the external shear stress would first induce channel deformation in VECs. This deformation could activate the Cl(-) channels on the membrane, thus allowing Cl(-) transport across the membrane. A modified Hodgkin-Huxley model is embedded into our dynamic system to describe the electrophysiological properties of the membrane, such as the Cl(-)-selective membrane current (I), voltage (V) and conductance. Three flow patterns, i. e., steady flow, oscillatory flow, and pulsatile flow, are applied in our simulation studies. When the extracellular Cl(-) concentration is constant, the I-V characteristics predicted by our dynamic model shows strong consistency with the experimental observations. It is also interesting to note that the Cl(-) currents under different flow patterns show some differences, indicating that VECs distinguish among and respond differently to different types of flows. When the extracellular Cl(-) concentration keeps constant or varies slowly with time (i.e. oscillates at 0.02 Hz), the convection and diffusion of Cl(-) in extracellular space can be ignored and the Cl(-) current is well captured by the modified Hodgkin-Huxley model alone. However, when the extracellular Cl(-) varies fast (i.e., oscillates at 0.2 Hz), the convection and diffusion effect should be considered because the Cl(-) current dynamics is different from the case where the convection-diffusion effect is simply ignored. The proposed dynamic model along with the simulation results could not only provide more insights into the flow-regulated electrophysiological behavior of the cell membrane but also help to reveal new findings in the electrophysiological experimental investigations of VECs in response to dynamic flow and biochemical stimuli.

Four new fatty acid esters from the Feces of Trogopterus xanthipes.

Four new fatty acid esters have been isolated from Feces Trogopterus. Their structures were determined by spectroscopic and chemical methods to be bis(7-hydroxyheptyl) icosanedioate (1), bis(7-hydroxyheptyl) heptadecanedioate (2), bis(7-hydroxyheptyl) decanedioate (3), and bis(7-hydroxyheptyl) octanedioate (4). In the anticoagulative assay, compounds 3 and 4 had significant antithrombin activity.

Dynamic modeling for shear stress induced ATP release from vascular endothelial cells.

A dynamic model is proposed for shear stress induced adenosine triphosphate (ATP) release from endothelial cells (ECs). The dynamic behavior of the ATP/ADP concentration at the endothelial surface by viscous shear flow is investigated through simulation studies based on the dynamic ATP release model. The numerical results demonstrate that the ATP/ADP concentration against time at endothelium-fluid interface predicted by the dynamic ATP release model is more consistent with the experimental observations than that predicted by previous static ATP release model.