An earthworm protease cleaving serum fibronectin and decreasing HBeAg in HepG2.2.15 cells

<p>Abstract</p> <p>Background</p> <p>Virus-binding activity is one of the important functions of fibronectin (FN). It has been reported that a high concentration of FN in blood improves the transmission frequency of hepatitis viruses. Therefore, to investigate a protease that hydrolyzes FN rapidly is useful to decrease the FN concentration in blood and HBV infection. So far, however, no specific protease digesting FN in serum has been reported.</p> <p>Methods</p> <p>We employed a purified earthworm protease to digest serum proteins. The rapidly cleaved protein (FN) was identified by MALDI-TOF MS and western blotting. The cleavage sites were determined by N-terminus amino acid residues sequencing. The protease was orally administrated to rats to investigate whether serum FN <it>in vivo </it>became decreased. The serum FN was determined by western blotting and ELISA. In cytological studies, the protease was added to the medium in the culture of HepG2.2.15 cells and then HBsAg and HBeAg were determined by ELISA.</p> <p>Results</p> <p>The protease purified from earthworm <it>Eisenia fetida </it>was found to function as a fibronectinase (FNase). The cleavage sites on FN by the FNase were at R and K, exhibiting a trypsin alkaline serine-like function. The earthworm fibronectinase (EFNase) cleaved FN at four sites, R₂₅₉, R₁₀₀₅, K₁₅₅₇and R₂₀₃₉, among which the digested fragments at R₂₅₉, K₁₅₅₇and R₂₀₃₉were related to the virus-binding activity as reported. The serum FN was significantly decreased when the earthworm fibronectinase was orally administrated to rats. The ELISA results showed that the secretion of HBeAg from HepG2.2.15 cells was significantly inhibited in the presence of the FNase.</p> <p>Conclusion</p> <p>The earthworm fibronectinase (EFNase) cleaves FN much faster than the other proteins in serum, showing a potential to inhibit HBV infection through its suppressing the level of HBeAg. This suggests that EFNase is probably used as one of the candidates for the therapeutic agents to treat hepatitis virus infection.</p

Comparison of the efficacy of tenofovir and adefovir in the treatment of chronic hepatitis B: A Systematic Review

Chronic viral hepatitis B remains a global public health concern. Currently, several drugs, such as tenofovir and adefovir, are recommended for treatment of patients with chronic hepatitis B. tenofovir is a nucleoside analog with selective activity against hepatitis b virus and has been shown to be more potent in vitro than adefovir. But the results of trials comparing tenofovir and adefovir in the treatment of chronic hepatitis B were inconsistent. However, there was no systematic review on the comparison of the efficacy of tenofovir and adefovir in the treatment of chronic hepatitis B. To evaluate the comparison of the efficacy of tenofovir and adefovir in the treatment of chronic hepatitis B we conducted a systematic review and meta-analysis of clinical trials. We searched PUBMED, Web of Science, EMBASE, CNKI, VIP database, WANFANG database, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Review. Finally six studies were left for analysis which involved 910 patients in total, of whom 576 were included in tenofovir groups and 334 were included in adefovir groups. At the end of 48-week treatment, tenofovir was superior to adefovir at the HBV-DNA suppression in patients[RR = 2.59; 95%CI(1.01-6.67), P = 0.05]. While there was no significant difference in the ALT normalization[RR = 1.15; 95%CI(0.96-1.37), P = 0.14], HBeAg seroconversion[RR = 1.32; 95%CI(1.00-1.75), P = 0.05] and HBsAg loss rate[RR = 1.19; 95%CI(0.74-1.91), P = 0.48]. More high-quality, well-designed, randomized controlled, multi-center trails are clearly needed to guide evolving standards of care for chronic hepatitis B

Searching for dark-matter induced neutrino signals in dwarf spheroidal galaxies using 10 years of IceCube public data

This study searches for neutrino signals from 18 dwarf spheroidal galaxies (dSphs) using 10 years of publicly available muon-track data of the IceCube neutrino observatory. We apply an unbinned likelihood analysis on each of these dSphs to derive the significance the putative neutrino emission. To further enhance our sensitivity, we also stack all dSphs together to perform a joint analysis. However, no significant neutrino emission signal was detected in either the single-source or stacking analysis. Based on these null results, we derive constraints on the annihilation cross section of dark matter particles. Compared to the existing literature, our constraints via the channel $\chi\chi\rightarrow\mu^+\mu^-$ are comparable to the ones from the VERITAS observations of dSphs

In vitro degradation and biocompatibility of vitamin C loaded Ca-P coating on a magnesium alloy for bioimplant applications

Molecular recognition was utilized to fabricate bioinspired calcium phosphate (Ca-P) coating on bioabsorbable magnesium alloys through small biomolecules such as Vitamin C (VC). Ca-P and VC hybrid coating (Ca-PVC) was successfully fabricated on AZ31 Mg alloy. The surface morphology and chemical composition of the coatings were investigated using SEM, XRD, and FTIR together with XPS. The results showed that the Ca-PVC coating was composed of bamboo leaf-like Ca-P particles with a thickness of about three times that of the Ca-P coating. The surface roughness of the Ca-PVC coating (1.12 ± 0.12 µm) was lower than that (3.14 ± 1.93 µm) of Ca-P coating, suggesting the formation of refined Ca-P particles resulting from the VC addition. The corrosion resistance of the coated samples was characterized via electrochemical polarization, impedance spectroscopy, and immersion hydrogen evolution tests. The cell toxicity of the coated samples was evaluated utilizing mouse MC3T3-E1 pre-osteoblasts. The charge transfer resistance (Rct) of the Ca-PVC coated alloy increased as compared to the bare and Ca-P coated alloy samples. The Ca-PVC coated alloy exhibited minimal corrosion current density (1.36 × 10−6 A cm−2), which is one order of magnitude lower in comparison to that of the Ca-P coated alloy. These results confirm that VC addition greatly enhanced the coating resistance on AZ31 Mg alloy. It was also noticed that the Ca-PVC coated samples rapidly induced the formation of apatite after immersion in Hank's solution. VC was mainly transformed to L-Threonic acid, which facilitated the nucleation process of the Ca-PVC coating and significantly increased the thickness, density, and bonding strength of the coating. With enhanced corrosion resistance property and excellent biocompatibility, Ca-PVC coating has great potential for application in biodegradable Mg-based alloys

Skp2 expression unfavorably impacts survival in resectable esophageal squamous cell carcinoma

<p>Abstract</p> <p>Background</p> <p>The correlation of S-phase kinase–associated protein 2 (Skp2) with metastasis and prognosis in esophageal squamous cell carcinoma (ESCC) is controversial. The purpose of this study was to explore whether there was a correlation between the expression of Skp2 evaluated by immunohistochemistry and the clinical outcome of patients with operable ESCC, and to further determine the possible mechanism of the impact of Skp2 on survival.</p> <p>Methods</p> <p>Tissue microarrays that included 157 surgically resected ESCC specimens was successfully generated for immunohistochemical evaluation. The clinical/prognostic significance of Skp2 expression was analyzed. Kaplan-Meier analysis was used to compare the postoperative survival between groups. The prognostic impact of clinicopathologic variables and Skp2 expression was evaluated using a Cox proportional hazards model. A cell proliferation assay and a colony formation assay were performed in ESCC cell lines to determine the function of Skp2 on the progression of ESCC <it>in vitro</it>.</p> <p>Results</p> <p>Skp2 expression correlated closely with the T category (<it>p</it> = 0.035) and the pathological tumor-node-metastasis (TNM) stage (<it>p</it> = 0.027). High expression of Skp2 was associated with poor overall survival in resectable ESCC (<it>p</it> = 0.01). The multivariate Cox regression analysis demonstrated that pathological T category, pathological N category, cell differentiation, and negative Skp2 expression were independent factors for better overall survival. <it>In vitro</it> assays of ESCC cell lines demonstrated that Skp2 promoted the proliferative and colony-forming capacity of ESCCs.</p> <p>Conclusions</p> <p>Negative Skp2 expression in primary resected ESCC is an independent factor for better survival. Skp2 may play a pro-proliferative role in ESCC cells.</p

Metal-organic frameworks displaying single crystal-to-single crystal transformation through postsynthetic uptake of metal clusters

NNSF of China [21021061, 20923004]; Specialized Research Fund for the Doctoral Program of Higher Education [2011012 1110012]Three metal-organic frameworks(MOFs) formulated as [Co3O(BTB)(2)(H2O)x(DMF)(y)]center dot zDMF center dot nH(2)O(BTB 1,3,5-benzenetribenzoate; 1a, x = y = 1, z = 7.5, n = 12; 1b, x = 2, y = 0, z = 8.5, n = 8; 1c, x = 2, y = 1, z = 7, n = 8) have been synthesized under different temperatures; they crystallize as two-fold interpenetrated analogous structures with the same structural trinuclear Co3O(CO2)(6) secondary building units (SBUs), and their stabilities depend on the temperature under which they formed. Upon immersion in the filtrate of 1a (namely 1a-s, freshly filtered) or 1b (namely 1b-s, filtered and then activated in air for three days), single crystal-to-single crystal (SCSC) transformations of 1a-1c to a new MOF, formulated as [Co6O2(OH)4(BTB)(8/3)(H2O)(4)]center dot 14DMF center dot 4EtOH center dot 2H(2)O (2), occur along with dramatic color change from blue purple to red. Crystallographic studies reveal that the new MOF is also two-fold interpenetrated but is constructed with hexanuclear Co6O2(CO2)(8) SBUs. This SCSC transformation from 1a-1c to 2 can take place only in 1a-s or 1b-s but not in 1c-s and is accompanied with an increase of metal-to-ligand ratio. ESI-MS studies unveil the formation of free {Co3O} units in situ formed only in 1a-s and 1b-s, and evidence that the SCSC transformation involves a postsynthetic uptake of free metal clusters, {Co3O}. On the other hand, the SCSC transformation speed decreases from 1a to 1c, which is determined by the chelate carboxylate groups undergoing cleavage of metal-carboxylate bonds during the SCSC transformation and the shape of the 1D channels affecting the diffusion of free metal clusters. Furthermore, the resulting MOF (2) can maintain its crystallinity upon activation and adsorbs iodine up to 38 wt%. Combined with the significant SCSC transformation through postsynthetic uptake of free metal clusters and the resulting MOF capable of adsorbing iodine, the present approach not only provides a true route to construct SBUs-based MOF materials with pre-existing "real" SBUs but also represent a new type of SCSC transformation in the field of MOFs that is able to efficiently tune structures and physicochemical properties of MOFs in the solid states

Facile and straightforward synthesis of superparamagnetic reduced graphene oxide–Fe3O4 hybrid composite by a solvothermal reaction

E-mail Addresses: [email protected] superparamagnetic reduced graphene oxide-Fe3O4 hybrid composite (rGO-Fe3O4) was prepared via a facile and straightforward method through the solvothermal reaction of iron (III) acetylacetonate (Fe(acac)(3)) and graphene oxide (GO) in ethylenediamine (EDA) and water. By this method, chemical reduction of GO as well as the formation of Fe3O4 nanoparticles (NPs) can be achieved in one step. The Fe3O4 NPs are firmly deposited on the surfaces of rGO, avoiding their reassembly to graphite. The rGO sheets prevent the agglomeration of Fe3O4 NPs and enable a uniform dispersion of these metal oxide particles. The size distribution and coverage density of Fe3O4 NPs deposited on rGO can be controlled by varying the initial mass ratio of GO and iron precursor, Fe(acac)(3). With an initial mass ratio of GO and Fe(acac)(3) of 5:5, the surfaces of rGO sheets are densely covered by spherical Fe3O4 NPs with an average size of 19.9 nm. The magnetic-functionalized rGO hybrid exhibits a good magnetic property and the specific saturation magnetization (M-S) is 13.2 emu g(-1). The adsorption test of methylene blue from aqueous solution demonstrates the potential application of this rGO-Fe3O4 hybrid composite in removing organic dyes from polluted water.National Key Basic Research Program of China 2013CB933901 National Natural Science Foundation of China 21171140 21021061 21031004 U1205111 Fundamental Research Funds for the Central Universities 2011121013 2012121020 NFFTBS J103041

Probing Hydrogen Bond Energies by Mass Spectrometry

E-mail Addresses: [email protected]; [email protected] spectrometry with desorption electrospray ionization (DESI) is demonstrated to be useful for probing the strength of hydrogen bonding, exemplified by various complexes of benzothiazoles and carboxylic acids in the solid state. Efficiencies for fragmentation of the complexes, quantified by collision-induced dissociation (CID) technology, correspond well with energies of the hydrogen bonds of O-H center dot center dot center dot N and N-H center dot center dot center dot O bridging each pair of benzothiazole and carboxylic acid. Linear correlations (with correlation factors of 0.8953 and 0.9928) have been established for the calibration curves of normalized collision energy at 100% fragmentation rate vs the length between donor and acceptor (in the hydrogen bond of O-H center dot center dot center dot N) as well as the slope of the fragmentation efficiency curve vs the average length difference between O-H center dot center dot center dot N and N-H center dot center dot center dot O in the complex. The mechanism responsible for determination of the hydrogen bonds is proposed on the basis of the experiments starting from the mixtures of the complexes as well as labeling with deuterium. As a complement of previously available methods (e.g., X-ray diffraction analysis), expectably, the proposed mass spectrometric method seems to be versatile for probing hydrogen bond energies.NNSF of China 21031004 21021061 U120511