[Hepatitis B surface antigen affects the expression of lipid metabolism-related genes in HepG2 cells].

OBJECTIVE: To investigate the influence of hepatitis B virus (HBV)-encoded small surface protein (SHBs) on hepatic cell expression of host genes related to lipid metabolism. METHODS: The full-length SHBs gene was amplified from HBV genotype C by polymerase chain reaction (PCR) and cloned into the pcDNA3.1(+) expression vector for stable transfection into HepG2 cells (selected by G418 screening); cells transfected with empty vector served as control. The SHBs mRNA and protein levels were detected by reverse transcription-PCR and enzyme-linked immunosorbent assay. SHBs effects on expression of genes and proteins related to lipid metabolism were detected by real-time quantitative (q)PCR and western blotting, respectively. RESULTS: The stably transfected cell line HepG2-pn3.1-SHBs was established successfully. qPCR showed that the HepG2-pn3.1-SHBs cells had significantly down-regulated transcription of the ECHS1, APOA1 and LPL genes (0.161+/-0.043 vs. control cells: 0.210+/-0.022, t = 2.479; 0.031+/-0.007 vs. 0.094+/-0.055, t = 2.752; 0.770+/-0.036 vs. 0.982+/-0.031, t = 10.914), but significantly up-regulated ACC and SREBP-1c genes (0.113+/-0.027 vs. 0.059+/-0.022, t = -3.757; 0.019+/-0.002 vs. 0.015+/-0.001, t = -4.330). The CPT1a and PPARa genes' expression was slightly, but not significantly, down-regulated in the HepG2-pn3.1-SHBs cells (0.028+/-0.005 vs. 0.030+/-0.004, t = 1.022; 0.014+/-0.004 vs. 0.015+/-0.002, t = 0.758). Western blotting showed similar expression trends for the corresponding proteins. CONCLUSION: SHBs alters the expression of some host genes with known functions in fatty acid synthesis and decomposition; however, it remains unclear whether the hepatitis B surface antigen can directly contribute to development of hepatic steatosis.

Structure of an unprecedent glucuronoxylogalactoglucomannan from fruit bodies of Auricularia auricula-judae (black woody ear).

An unprecedent glucuronoxylogalactoglucomannan (GXG'G″M), ME-2 (Mw, 2.60 × 105 g/mol; O-acetyl % = 16.7 %), was isolated and purified from water extracts of Auricularia auricula-judae (black woody ear). Firstly, due to much higher O-acetyl contents, we prepared its fully deacetylated products (dME-2; Mw, 2.13 × 105 g/mol) for convenient structure survey. The repeating structure-unit of dME-2 was readily proposed based on Mw determination, monosaccharide compositions, methylation analysis, free-radical degradation and 1/2D NMR spectroscopy. The dME-2 was identified as a highly branched polysaccharide with an average of 10 branches per 10 sugar backbone units. The backbone was only repeating →3)-α-Manp-(1→ residues, substituted at the C-2, C-6 and C-2,6 positions. The side chains included ß-GlcAp-(1→, ß-Xylp-(1→, α-Manp-(1→, α-Galp-(1→ and ß-Glcp-(1→. Secondly, the complex substituted positions of O-acetyl groups in ME-2 were determined to be at C-2, C-4, C-6 and C-4,6 in the backbone and at C-2 and C-2,3 in some side chains. Finally, the anti-inflammatory activity of ME-2 was preliminarily explored on LPS-stimulated THP-1 cells. The above date not only provided the first example for structural studies of GXG'G″M type polysaccharides, but also facilitated development and application of black woody ear polysaccharides as medicinal agents or functional dietary supplements.

[The immunomodulatory effects of sijunzi decoction and its disassembled prescription on D-galactose-induced aging mice].

OBJECTIVE: To observe the immunomodulatory effects of codonopsis, atractylodes macrocephala, tuceahoe, broiled licorice and sijunzi decoction on D-galactose-induced aging mice. METHODS: The models of aging mice were induced by D-galactose, the garlands and splenic lymphocyte transformation test (MTT) were used to determine the ability of erythrocytes immune and lymphocytes conversion; The content of maleic dialdehyde (MDA), activity of superoxide dismutase (SOD) and glutathione pemfidase (GSH-Px) in serum were detected. RESULTS: Sijunzi decoction and its disassembled prescription codonopsis could significantly increase the ability of T lymphocyte transformation (P<0.05); Atractylodes macrocephala and sijunzi decoction could significantly enhance C(3b) garlands ratio (P<0.05) and decrease IC garlands ratio (P<0.05) on D-galactose-induced aging mice. Sijunzi decoction significantly increased the activity of SOD and GSH-Px (P<0.01), and decreased the content of MDA in serum (P<0.05). CONCLUSION: Sijunzi decoction and its disassembled prescription codonopsis, atractylodes macrocephala can improve the immunomodulatory effects on D-galactose-induced aging mice; but tuceahoe and broiled licorice have no obvious effects.

A novel in situ stress measurement method based on acoustic emission Kaiser effect: a theoretical and experimental study.

Measurement of in situ stress is critical to understand the deformation and destruction of the underground space surrounding rock, and dynamic disaster of the coal mine. At present, with the increasing depth of mining, in situ stress parameters are more and more important for coal mine. In this paper, a novel method for in situ stress measurement with Kaiser effect was studied and applied in the Baijiao coal mine. First, we presented a comprehensive analysis method for the identification of Kaiser effect point. Then, a calculation method for in situ stress measurement based on the Kaiser effect on acoustic emissions was suggested. After that, the in situ stress test of Baijiao coal mine is taken as the research object, an experiment using acoustic emissions monitoring during uniaxial compression testing was performed to investigate the mechanical properties and acoustic emissions characteristics. Finally, in situ stress of the study area was calculated using the novel calculation method above and calculation results were verified using stress relief method and hydraulic fracturing method. The results showed that the calculation results obtained using the proposed method were valid and credible. Therefore, the calculation method for in situ stress measurement and the proposed comprehensive analysis method using the Kaiser point could be applied for in situ stress testing using the Kaiser effect method.

Carboxylic Terminated Thermo-Responsive Copolymer Hydrogel and Improvement in Peptide Release Profile.

To improve the release profile of peptide drugs, thermos-responsive triblock copolymer poly (ε-caprolactone-co-p-dioxanone)-b-poly (ethylene glycol)-b-poly (ε-caprolactone-co-p-dioxanone) (PECP) was prepared and end capped by succinic anhydride to give its carboxylic terminated derivative. Both PCEP block copolymer and its end group modified derivative showed temperature-dependent reversible sol-gel transition in water. The carboxylic end group could significantly decrease the sol-gel transition temperature by nearly 10 °C and strengthen the gel due to enhanced intermolecular force among triblock copolymer chains. Furthermore, compared with the original PECP triblock copolymer, HOOC-PECP-COOH copolymer displayed a retarded and sustained release profile for leuprorelin acetate over one month while effectively avoiding the initial burst. The controlled release was believed to be related to the formation of conjugated copolymer-peptide pair by ionic interaction and enhanced solubility of drug molecules into the hydrophobic domains of the hydrogel. Therefore, carboxyl terminated HOOC-PECP-COOH hydrogel was a promising and well-exhibited sustained release carrier for peptide drugs with the advantage of being able to develop injectable formulation by simple mixing.

A self-consistent determination of the RVB and SC gaps in the YRZ ansatz.

A correct understanding of the origin of the pseudogap in high temperature (high-T c) cuprate superconductors is considered to be a peripheral breakthrough in the understanding of the microscopic mechanism of the high-T c superconductivity. Yang-Rice-Zhang (YRZ) ansatz is an important phenomenological theory to describe the phenomenon of pseudogap. However, in the framework of YRZ, the pseudogap (resonant valence bond (RVB) gap) and the superconducting (SC) gap are unable to have a self-consistent determination at different doping concentrations, and this severely limits the application of the YRZ ansatz. Based on the YRZ ansatz, this study develops a technical method to determine the RVB and SC gaps in a self-consistent manner. It is revealed that the self-consistent calculations of the doping dependence of RVB, SC gaps and spectral function are not only consistent with the empirical gap formula in the YRZ framework, but also consistent with the doping evolution of the Fermi surface observed in the angle-resolved photoemission spectroscopy (ARPES) experiments. Our method will greatly extend the applications of the YRZ ansatz, and will deepen our understanding of the origin of pseudogap as well as the mechanism of high-T c superconductivity.

[Using GST-tag to capture protein interaction of an interferon-inducible systemic lupus associated gene, IFIT1].

OBJECTIVE: To investigate the protein-to-protein interaction of interferon-induced protein with tetratricopeptide repeats 1 (IFIT1), a newly discovered systemic lupus erythematosus (SLE) related up-regulated gene, and its possible function. METHODS: Peripheral blood of 40 SLE patients was obtained to extract total RNA and synthesized cDNA. Real-time PCR was used to determine the IFIT1 expression at transcript level. Peripheral blood of another 10 SLE patients was extracted to obtain specimens of white blood cell lysate. Molecular cloning and a modified gluthion S-transferase (GST)-pull down assay were used to capture the protein interacting with IFIT1 in the specimens of white blood cell lysate. MALDI-TOF mass spectrometry (MS) was preformed to identify the captured protein that could interact with IFIT1. Twenty-nine sex and age-matched healthy persons were used as controls. RESULTS: By real-time PCR showed that the IFIT1Delta Ct value (x +/- s) was 2.344 +/- 1.200 in the SLE patients and was 3.734 +/- 1.274 in the controls (P < 0.001), showing a significant up-regulation in SLE patients. IFIT1 was cloned and GST-IFIT1 fusion protein was expressed in Escherichia coli. GST-IFIT1 fusion protein was further purified using Glutathione Sepharose 4B column, and was treated as bait to capture prey from peripheral white blood cell lysate of SLE patients. MALDI-TOF MS detected protein interaction between Rho/Rac guanine nucleotide exchange factor and IFIT1. CONCLUSION: IFIT1 may interact with Rho/Rac guanine nucleotide exchange factor, and regulate the activation of Rho/Rac proteins, thus being involved in the pathogenesis of SLE.

Insight derived from molecular dynamics simulation into substrate-induced changes in protein motions of proteinase K.

Because of the significant industrial, agricultural and biotechnological importance of serine protease proteinase K, it has been extensively investigated using experimental approaches such as X-ray crystallography, site-directed mutagenesis and kinetic measurement. However, detailed aspects of enzymatic mechanism such as substrate binding, release and relevant regulation remain unstudied. Molecular dynamics (MD) simulations of the proteinase K alone and in complex with the peptide substrate AAPA were performed to investigate the effect of substrate binding on the dynamics/molecular motions of proteinase K. The results indicate that during simulations the substrate-complexed proteinase K adopt a more compact and stable conformation than the substrate-free form. Further essential dynamics (ED) analysis reveals that the major internal motions are confined within a subspace of very small dimension. Upon substrate binding, the overall flexibility of the protease is reduced; and the noticeable displacements are observed not only in substrate-binding regions but also in regions opposite the substrate-binding groove/pockets. The dynamic pockets caused by the large concerted motions are proposed to be linked to the substrate recognition, binding, orientation and product release; and the significant displacements in regions opposite the binding groove/pockets are considered to play a role in modulating the dynamics of enzyme-substrate interaction. Our simulation results complement the biochemical and structural studies, highlighting the dynamic mechanism of the functional properties of proteinase K.

Expression, purification and crystal structure of a truncated acylpeptide hydrolase from Aeropyrum pernix K1.

Acylpeptide hydrolase (APH) catalyzes the N-terminal hydrolysis of Nalpha-acylpeptides to release Nalpha-acylated amino acids. The crystal structure of recombinant APH from the thermophilic archaeon Aeropyrum pernix K1 (apAPH) was reported recently to be at a resolution of 2.1 Angstrom; using X-ray diffraction. A truncated mutant of apAPH that lacks the first short alpha-helix at the N-terminal, apAPH-delta(1-21), was cloned, expressed, characterized and crystallized. Data from biochemical experiments indicate that the optimum temperature of apAPH is decreased by 15 degrees C with the deletion of the N-terminal alpha-helix. However, the enzyme activity at the optimal temperature does not change. It suggests that this N-terminal alpha-helix is essential for thermostability. Here, the crystal structure of apAPH-delta(1-21) has been determined by molecular replacement to 2.5 Angstrom;. A comparison between the two structures suggests a difference in thermostability, and it can be concluded that by adding or deleting a linking structure (located over different domains), the stability or even the activity of an enzyme can be modified.