Analysis of bacterial and fungal community structure in replant strawberry rhizosphere soil with denaturing gradient gel electrophoresis

High quality DNA is the basis of analyzing bacterial and fungal community structure in replant strawberry rhizosphere soil with the method of denaturing gradient gel electrophoresis (DGGE). DNA of soil  microorganisms was extracted from the rhizosphere soil of strawberries planted in different replanted  years (0, two, six and seven), respectively, and crude DNA was purified after extraction. Three methods  were established to evaluate the effects of cetyl trimethylammonium bromide (CTAB),  polyvinylpolypyrolidone (PVPP), proteinase K and bacteriolytic enzymes on DNA extraction. DNA  fragments above 23 kb in size were isolated well by method 1 (1% CTAB, proteinase K, no PVPP, no  bacteriolytic enzyme) and method 3 (no CTAB, no proteinase K, 3% PVPP, bacteriolytic enzyme). Method 3 got the best yields 43.06 ìg/g, and A260/A280 and A260/A230 were 1.1623 and 0.8135, respectively,  which could ensure the veracity of subsequent DGGE analysis. Method 2 (3% CTAB, no proteinase K, no PVPP, no bacteriolytic enzyme) could not extract enough DNA to do the next PCR-DGGE analysis.  F341/R534 and FR1/FF390 primers were used to amplify the 16S rDNA V3 region of bacteria and 18S rDNA of fungi, and the expected fragments of 230 bp 16S rDNA V3 region and 390 bp 18S rDNA were amplified. The results of DGGE analysis showed that there were common and specific bacterial and fungal  communities in different replant soils of strawberry. There were 84 and 54% similarity of bacterial and  fungal communities between different replant soils. The numbers of both bacterial and fungal communities increased in the replant strawberry soil, they were positively correlated with the replant years. As the  number of replant years increased from two to seven years, while the ratio of bacteria/fungi was  decreased from 2.29 to 1.46 in the rhizosphere soils planted with strawberries.Key words: Rhizosphere soil, bacterial community, fungal community, replant strawberry, fruiting fields

Vitamin E δ-tocotrienol Sensitizes Human Pancreatic Cancer Cells to TRAIL-induced Apoptosis Through Proteasome-Mediated Down-Regulation of c-FLIP

Background: Vitamin E δ-tocotrienol (VEDT), a vitamin E compound isolated from sources such as palm fruit and annatto beans, has been reported to have cancer chemopreventive and therapeutic effects. Methods: We report a novel function of VEDT in augmenting tumor necrosis factor-related apoptosis-inducing ligand- (TRAIL-) induced apoptosis in pancreatic cancer cells. The effects of VEDT were shown by its ability to trigger caspase-8-dependent apoptosis in pancreatic cancer cells. Results: When combined with TRAIL, VEDT significantly augmented TRAIL-induced apoptosis of pancreatic cancer cells. VEDT decreased cellular FLICE inhibitory protein (c-FLIP) levels without consistently modulating the expression of decoy death receptors 1, 2, 3 or death receptors 4 and 5. Enforced expression of c-FLIP substantially attenuated VEDT/TRAIL-induced apoptosis. Thus, c-FLIP reduction plays an important part in mediating VEDT/TRAIL-induced apoptosis. Moreover, VEDT increased c-FLIP ubiquitination and degradation but did not affect its transcription, suggesting that VEDT decreases c-FLIP levels through promoting its degradation. Of note, degradation of c-FLIP and enhanced TRAIL-induced apoptosis in pancreatic cancer cells were observed only with the anticancer bioactive vitamin E compounds δ-, γ-, and β-tocotrienol but not with the anticancer inactive vitamin E compounds α-tocotrienol and α-, β-, γ-, and δ-tocopherol. Conclusions: c-FLIP degradation is a key event for death receptor-induced apoptosis by anticancer bioactive vitamin E compounds in pancreatic cancer cells. Moreover, VEDT augmented TRAIL inhibition of pancreatic tumor growth and induction of apoptosis in vivo. Combination therapy with TRAIL agonists and bioactive vitamin E compounds may offer a novel strategy for pancreatic cancer intervention

TGF-β1 Exerts Opposing Effects on Grass Carp Leukocytes: Implication in Teleost Immunity, Receptor Signaling and Potential Self-Regulatory Mechanisms

In fish immunity, the regulatory role of transforming growth factor-β1 (TGF-β1) has not been fully characterized. Here we examined the immunoregulatory effects of TGF-β1 in grass carp peripheral blood leukocytes (PBL) and head kidney leukocytes (HKL). It is interesting that TGF-β1 consistently stimulated the cell viability and the mRNA levels of pro-inflammatory cytokines (Tnfα and Ifnγ) and T/B cell markers [Cd4-like (Cd4l), Cd8α, Cd8β and Igμ] in PBL, which contrasted with its inhibitory tone in HKL. Further studies showed that grass carp TGF-β1 type I receptor, activin receptor-like kinase 5 (ALK5), was indispensable for the immunoregulatory effects of TGF-β1 in PBL and HKL. Notably, TGF-β1 persistently attenuated ALK5 expression, whereas immunoneutralization of endogenous grass carp TGF-β1 could increase ALK5 mRNA and protein levels. It is consistent with the observation that TGF-β1 decreased the number of ALK5+ leukocytes in PBL and HKL, revealing a negative regulation of TGF-β1 signaling at the receptor level. Moreover, transient treatment with TGF-β1 for 24 h was sufficient to induce similar cellular responses compared with the continuous treatment. This indicated a possible mechanism by which TGF-β1 triggered the down-regulation of ALK5 mRNA and protein, leading to the desensitization of grass carp leukocytes toward TGF-β1. Accordingly, our data revealed a dual role of TGF-β1 in teleost immunity in which it can serve as a positive or negative control device and provided additional mechanistic insights as to how TGF-β1 controls its signaling in vertebrate leukocytes

Molecular Dynamics Simulation on Thin-Film Lubrication of a Mixture of Three Alkanes

We used the COMPASS forcefield to perform molecular dynamics (MD) simulation of a mixture composed of three alkanes as the lubricant for the thin-film lubrication. The viscosity of the lubrication film in the non-working state, the final film thickness, and density distribution were investigated. The results reveal that the viscosity error among different initial film thicknesses in the non-working state is within 5%, which confirms the applicability of the model and the forcefield. The viscosity decreases oscillating as temperature increases. Whatever the initial film thickness is, the film thickness change rate with respect to pressure load is almost the same. When pressure increases, the density peaks increase. As the initial film thickness increases, the normalized thicknesses of adsorption and ordered layers decrease. In nanoscale, the density predicted by the MD simulation is higher than the prediction of the Tait equation, even if the adsorption layers is excluded

Integration of Transcriptomic and Proteomic Analyses Reveals New Insights into the Regulation of Immune Pathways in Midgut of <em>Samia ricini</em> upon SariNPV Infection

Samia ricini nucleopolyhedrovirus (SariNPV) is one of the main pathogens of S. ricini sericulture and its infection causes severe impacts on economic sericulture development. To explore and reveal the molecular mechanisms of S. ricini in response to SariNPV infection, we employed RNA sequencing (RNA-seq), adopting isobaric tags for relative and absolute quantitation (iTRAQ), and carried out combination analysis of the obtained differentially expressed genes (DEGs) and proteins (DEPs). Through transcriptome sequencing, a total of 2535 DEGs were detected, and with iTRAQ, 434 DEPs with significant expression difference were identified. Through correlation analysis, we found that the expression trends of 116 differentially expressed proteins were the same as those of differentially expressed genes (including 106 up-regulated and 10 down-regulated). Twenty-five key differentially expressed genes (proteins) involved in several signaling and immune related pathways (mainly involving Toll, Imd, Jak-STAT and Wnt signaling pathways, as well as other immune related pathways) were screened through real-time quantitative PCR. Our results, not only provide insights into the pathogenic mechanism of SariNPV infection in ricin silkworm and the immune response mechanism within the host, but also provide a significant contribution for identifying and preventing diseases caused by SariNPV

The Analysis of Carbon Emission&rsquo;s Characteristics and Dynamic Evolution Based on the Strategy of Unbalanced Regional Economic Development in China

Analyzing the evolution law of carbon emissions is particularly important for the designation of policies on energy conservation and emission reduction. Based on the regional division of China, this paper uses a spatial panel model to find the causes of the differences in carbon emission, and the non-parametric model, logarithmic mean Divisia index (LMDI) model and the extended STIRPAT model to analyze the relevant influencing factors in detail. From the studies in this paper, there come the following conclusions: (1) The environmental Kuznets curve (EKC) in the eastern region resembles the national EKC, demonstrating the same &ldquo;N&rdquo; pattern. However, the &ldquo;upside-down U&rdquo; pattern in the middle and western regions not only confirms the assumption of EKC in some Chinese regions but also demonstrates the effective restraint in high energy consumption and high emission levels when narrowing down the gaps between the central and western regions and the eastern regions. (2) In addition, good education can effectively suppress the increase in carbon emission, and every 1% increase in the proportion of educated people (college and above) results in emission reduction, respectively, by 0.22%, 0.51% and 0.44% in the eastern, central and western regions of China. (3) Significantly, the effect of tertiary industry structure on carbon emissions is positive, reflecting the trend of &ldquo;deterioration&rdquo; of China&rsquo;s industrial structure over long time scales. This study functions positively in understanding the evolutionary pattern of regional carbon emissions and proposing differentiated policies on emission reduction

Aqueous lubrication and surface microstructures of engineering polymer materials (PEEK and PI) when sliding against Si3N4

Abstract Polyether-ether-ketone (PEEK) and polyimide (PI) are two kinds of engineering polymer materials widely used as roller bearing cages and rings under extreme environment because of their noise reduction and corrosion resistance properties. The Si3N4 ceramic is the most common ball bearing material. Many current engineering applications of ball bearings require aqueous lubrication. Therefore, this study presents the aqueous lubrication of tribopairs formed by PEEK and PI material sliding against Si3N4 ceramic. Experimental results show that two tribopairs exhibited the similar tribological properties under the dry condition. Water as a lubricant for the PI–Si3N4 tribopair pairs effectively reduces both friction coefficients by 35.5% and wear rates by 32%. The water absorption of PI induces better tribological properties by changing the tribopair surface properties. In addition, the dimples appearing on the PI tribopair surface under water generate additional hydrodynamic lubrication and further improve the friction properties of surface. The PEEK–Si3N4 tribopair shows similar friction coefficients under two kinds of environments. The wear rates under water are approximately more than two times of that under dry sliding. However, water inhibits the appearance of the crush phenomenon and enhances the carrying capacity of the tribopair. Energy dispersive spectroscopy and X-ray diffraction spectra demonstrate no chemical corrosion. The 3D profiler and SEM morphologies illustrate that the transfer film would be formed from the surface of PEEK under water but hindered under dry friction. Overall, the PI–Si3N4 tribopair exhibits better properties than PEEK under water and is promising for future applications in the bearing industry

Construction strategy on outdoor environment of ecological community in dry region–Lanzhou, China

In order to improve the human thermal comfort of the ecological community, aiming at the characteristics of low humidity and large wind and sand in northwest areas such as Lanzhou, the method was proposed to improve the human thermal comfort by water evaporation from porous pavement. Firstly, the outdoor environmental model of the ecological community was established and the environmental parameters of a community are simulated by using the model in Lanzhou. The simulation results are compared with the experimental results, and the relative error is less than 15%. Secondly, the change law of outdoor thermal and humid environment is simulated and analysed when porous pavement and ordinary pavement are used in ecological community, respectively. The results show that the humid environment of the community has changed significantly and the maximum change is about 7% after considering the water evaporation from porous pavement. Meanwhile, the amount of single water sprayed onto the porous pavement should meet the water evaporation requirement of 1.67h under the climatic conditions at that time. The above research results provide theoretical guidance for improving the outdoor thermal comfort of residential buildings in dry region

Gas Chromatography-Mass Spectrometry Based Midgut Metabolomics Reveals the Metabolic Perturbations under NaF Stress in Bombyx mori

Fluoride tolerance is an important economic trait in sericulture, especially in some industrial development regions. Analyses of physiological changes involving structural damage to the insect body and molecular analyses of some related genes have focused on this area; however, the changes that occur at the metabolic level of silkworms after eating fluoride-contaminated mulberry leaves remain unclear. Here, metabonomic analysis was conducted using gas chromatography-mass spectrometry (GC-MS) to analyze the changes in midgut tissue after NaF stress using silkworm strains 733xin (susceptible stain) and T6 (strain resistant to fluoride), which were previously reported by our laboratory. Differential metabolomics analysis showed that both T6 and 733xin strains displayed complex responses after exposure to 200 mg/kg NaF. The purine metabolism and arginine and proline metabolic pathways of fluoride-tolerant strains reached significant levels, among which 3&prime;-adenylic acid and hypoxanthine were significantly upregulated, whereas guanine, allantoic acid, xanthine, N-acetyl-L-glutamic acid, and pyruvate were significantly downregulated. These metabolic pathways may be related to the fluoride tolerance mechanism of NaF poisoning and tolerant strains