Preparation of Smooth Surface TiO 2

Dye-sensitized solar cells (DSSCs) based on a TiO2 photoanode have been considered as an alternative source in the field of renewable energy resources. In DSSCs, photoanode plays a key role to achieve excellent photo-to-electric conversion efficiency. The surface morphology, surface area, TiO2 crystal phase, and the dispersion of TiO2 nanoparticles are the most important factors influencing the properties of a photoanode. The smooth TiO2 surface morphology of the photoanode indicates closely packed arrangement of TiO2 particles which enhance the light harvesting efficiency of the cell. In this paper, a smooth TiO2 photoanode has been successfully prepared using a well-dispersed anatase TiO2 nanosol via a simple hydrothermal process. The above TiO2 photoanode was then compared with the photoanode made from commercial TiO2 nanoparticle pastes. The morphological and structural analyses of both the aforementioned photoanodes were comprehensively characterized by scanning electron microscopy and X-ray diffraction analysis. The DSSC fabricated by using a-TiO2 nanosol-based photoelectrode exhibited an overall light conversion efficiency of 7.20% and a short-circuit current density of 13.34 mA cm−2, which was significantly higher than those of the DSSCs with the TiO2 nanoparticles-based electrodes

Alleviation of Carbon-Tetrachloride-Induced Liver Injury and Fibrosis by Betaine Supplementation in Chickens

Betaine is a food component with well-reported hepatoprotection effects. However, the effects and mechanisms of betaine on liver fibrosis development are still insufficient. Because metabolic functions of chicken and human liver is similar, we established a chicken model with carbon Tetrachloride- (CCl4-) induced fibrosis for studying antifibrotic effect of betaine in vivo and in vitro. Two-week-old male chicks were supplemented with betaine (1%, w/v) in drinking water for 2 weeks prior to the initiation of CCl4 treatment (i.p.) until sacrifice. Primary chicken hepatocytes were treated with CCl4 and betaine to mimic the in vivo supplementation. The supplementation of betaine significantly alleviated liver fibrosis development along with the inhibition of lipid peroxidation, hepatic inflammation cytokine, and transforming growth factor-β1 expression levels. These inhibitive effects were also accompanied with the attenuation of hepatic stellate cell activation. Furthermore, our in vitro studies confirmed that betaine provides antioxidant capacity for attenuating the hepatocyte necrosis by CCl4. Altogether, our results highlight the antioxidant ability of betaine, which alleviates CCl4-induced fibrogenesis process along with the suppression of hepatic stellate cells activation. Since betaine is a natural compound without toxicity, we suggest betaine can be used as a potent nutritional or therapeutic factor for reducing liver fibrosis

Embryonic cholesterol esterification is regulated by a cyclic AMP-dependent pathway in yolk sac membrane-derived endodermal epithelial cells.

During avian embryonic development, endodermal epithelial cells (EECs) absorb yolk through the yolk sac membrane. Sterol O-acyltransferase (SOAT) is important for esterification and yolk lipid utilization during development. Because the major enzyme for yolk sac membrane cholesteryl ester synthesis is SOAT1, we cloned the avian SOAT1 promoter and elucidated the cellular functions of SOAT1. Treatments with either glucagon, isobutylmethylxanthine (IBMX), an adenylate cyclase activator (forskolin), a cAMP analog (dibutyryl-cAMP), or a low glucose concentration all increased SOAT1 mRNA accumulation in EECs from Japanese quail, suggesting that SOAT1 is regulated by nutrients and hormones through a cAMP-dependent pathway. Activity of protein kinase A (PKA) was increased by IBMX, whereas co-treatment with the PKA inhibitor, H89 negated the increase in PKA activity. Cyclic AMP-induced EECs had greater cholesterol esterification than untreated EECs. By promoter deletion and point-mutation, the cAMP-response element (-349 to -341 bp) was identified as critical in mediating transcription of SOAT1. In conclusion, expression of SOAT1 was regulated by a cAMP-dependent pathway and factors that increase PKA will increase SOAT1 to improve the utilization of lipids in the EECs and potentially modify embryonic growth

Positive regulation of transcription and enzymatic function of <i>SOAT1</i>.

<p>(A-D) Effects of forskolin and dibutyryl-cyclic AMP (db-cAMP) on <i>SOAT1</i> mRNA accumulations in EECs and hepatocytes. EECs and hepatocytes were treated with different concentrations of forskolin or db-cAMP for 24 hours. <i>SOAT1</i> mRNA accumulation was measured and normalized to <i>β-actin</i> mRNA. (n = 4) (E-F) H89 inhibited IBMX-induced <i>SOAT1</i> mRNA accumulations in EECs and hepatocytes. <i>SOAT1</i> mRNA accumulation was increased by 0.5 mM IBMX treatment for 24 hours, whereas the PKA inhibitor, H89 (10 μM) abolished the IBMX-mediated increase of <i>SOAT1</i>. (n = 6) (G-H) The IBMX treatment increased PKA activity in EECs and hepatocytes. The cells were treated with 0.5 mM IBMX with or without 10 μM H89 for 24 hours. The cell lysates were assayed for PKA activity using the PepTag assay. Typical gel patterns are represented (three independent experiments) for EECs and hepatocytes with statistical analysis of the densitometric analysis represented by the graphs (quantified by ImageQuant software). (I) Fluorescence examination of <i>SOAT1</i> activity by applying NBD-cholesterol as the substrate. EECs were incubated with 10 μg/mL of NBD-cholesterol at 37°C for 30 mins or 1 hour. Green indicated the cholesterol ester inside of EECs and blue indicated cell nucleus stained with DAPI. (J-K) The fluorescent intensity was quantified by ImageJ software. EECs were treated with or without db-cAMP for 24 hours. EECs were then incubated with 10 μg/mL of NBD-cholesterol for 30 min or 1 hour and examined by confocal microscopy. (J) Fluorescent intensity of total area. K: Fluorescent intensity per area of lipid droplets in EECs. (n = 4) Statistical significance was determined by one-way analysis of variance. Tukey‘s test was used to evaluate differences between means. Control value was set as 1. Different letters indicate a significant difference (P≤0.05). (L) The <i>SOAT1</i> protein levels after db-cAMP or IBMX treatments. EECs were treated with 0.5 or 1 mM db-cAMP or 0.5 mM IBMX for 48 hours and protein levels were examined by Western blotting. The <i>β-actin</i> was used as internal control. Statistical significance was determined by one-way analysis of variance. Dunnett's multiple comparisons test was used to evaluate differences between means. Data were expressed as means ± S.E.M. (n = 8) and different letters indicate the significant difference (P≤0.05). (M-N) The effects of H89 with or without db-cAMP and IBMX treatments on NBD-cholesterol uptake and storage. (M) EECs were pre-treated with or without H89 (10 μM) for 2 hours, and added db-cAMP (1 mM) or IBMX (0.5 mM) for 24 hours. Cells were then incubated with 10 μg/mL NBD-cholesterol for one hour, fixed with 4% paraformaldehyde and finally examined by confocal microscopy. Green indicated the cholesterol ester inside of EECs and blue indicated cell nucleus stained with DAPI. Scale bar = 50 μm. (N) The quantitation of fluorescent intensity on NBD-cholesterol uptake and storage by ImageJ software in cells treated with H89 with or without IBMX or db-cAMP. Data were expressed as means ± S.E.M. (n = 4) Statistical significance among more than three different experimental groups was determined by one-way analysis of variance. Tukey‘s test was used to evaluate differences between means. Different letters indicate a significant difference (P≤0.05).</p

The importance of functional responsive elements CRE (cAMP-responsive element) on the <i>SOAT1</i> promoter.

<p>(A) Effect of IBMX and the PKA inhibitor, H89 on the induction of <i>SOAT1</i> promoter activity. Promoter activities were normalized for transfection efficiency using the renilla luciferase activity. (n = 5) (B) Effect of IBMX on the induction of serially deleted promoter regions of <i>SOAT1</i>. The 293T cells were transfected with variable length constructs of the <i>SOAT1</i> promoter and promoter activities were assayed after 24 hours of IBMX treatment. The pGL3 was a luciferase vector without <i>SOAT1</i> promoter insertion, and was used as a negative control. (n = 6) (C) Diagram of wild type and mutated cAMP-responsive element on the <i>SOAT1</i> promoter construct in a luciferase vector. (D) Effect of IBMX and H89 on the induction of promoter activity by the mutated CREB in the <i>SOAT1</i> promoter. The 293T cells were transfected with normal or mutated <i>SOAT1</i> promoter, and promoter activities were assayed after 0.5 mM IBMX and 10 μM H89 (PKA inhibitor) treatments for 24 hours. (n = 6) Data were expressed as means ± S.E.M. (n = three independent experiments) Statistical significance was determined by one-way analysis of variance. Tukey's test was used to evaluate differences between means. Control value was set as 1. Different letters indicate a significant difference (P≤0.05).</p

The chicken primers for real-time PCR quantification.

<p>The chicken primers for real-time PCR quantification.</p

Conditions and primers for serial promoter region deletion.

<p>Conditions and primers for serial promoter region deletion.</p

H89 inhibited IBMX-induced transcription factors mRNA accumulations in EECs and hepatocytes.

<p>Cells were treated with 0.5 mM IBMX alone for 24 h, <i>CREB1</i> and <i>CREBBP</i> mRNA accumulations were increased, whereas the H89 (PKA inhibitor, 10 μM) abolished the increased mRNA accumulations mediated by IBMX in both culture systems. Data were expressed as means ± S.E.M. (n = 6) Statistical significance was determined by one-way analysis of variance. Tukey's test was used to evaluate differences between means. Control value was set as 1. Different letters indicate a significant difference (P≤0.05).</p