Objective To explore the inhibitory effect of guggulsterone(GS)on diethylnitrosamine(DEN)-induced liver fibrosis in rats and its mechanism.Methods DEN-induced liver fibrosis model was established in SD rats.The successful model rats were randomly divided into model group(n=6),GS group(n=6,50 mg/kg,intraperitoneal injection for 4 weeks),GS+SRI group(n=6,50 mg/kg+30 mg/kg,intraperitoneal injection for 4 weeks),and control group(n=6,without DEN-induced).Rats in the control group and the model group were injected with the same amount of normal saline.The pathological changes of the liver were detected by HE staining.Serum liver function indexes including alanine aminotransferase(ALT),aspartate aminotransferase(AST),albumin(ALB)and alkaline phosphatase(ALP)were detected by automatic biochemical analyzer.The serum levels of pro-collagen Ⅲ(PC-Ⅲ),collagen Ⅳ(Ⅳ-C),hyaluronidase(HA),laminin(LN),malondialdehyde(MDA),reduced glutathione(GSH),superoxide dismutase(SOD),and catalase(CAT)were detected by ELISA assay.The mRNA and protein expression of TGF-β1,Smad2,and p-Smad3/Smad3 were detected by Real-time PCR and Western blotting.Results Compared with the control group,the model group showed typical pathological changes of liver fibrosis;the serum ALB,GSH,SOD and CAT levels were significantly decreased(P＜0.05);the serum levels of ALT,AST,ALP,MDA,PC-Ⅲ,Ⅳ-C,HA,LN and the mRNA expression of TGF-β1,Smad3 and protein expression of TGF-β1,p-Smad3 in liver tissues were significantly increased(P＜0.05).Compared with the model group,the pathological changes of liver fibrosis in the GS group were alleviated,and the serum levels of ALB,GSH,SOD and CAT were significantly increased(P＜0.05),the serum levels of ALT,AST,ALP,MDA,PC-Ⅲ,Ⅳ-C,HA and LN,the mRNA expression of TGF-β1 and Smad3,and protein expression of TGF-β1 and p-Smad3 in liver tissues were significantly decreased(P＜0.05).In addition,after the administration of SRI,TGF-β1 signaling pathway activator,compared with the GS group,the GS+SRI group showed significantly decreased serum ALB,GSH,SOD and CAT levels(P＜0.05),but significantly increased serum levels of ALT,AST,ALP,MDA,PC-Ⅲ,Ⅳ-C,HA and LN as well as the mRNA expression of TGF-β1 and Smad3 and protein expression of TGF-β1 and p-Smad3 in liver tissues(P＜0.05).Therefore,SRI attenuated the anti-fibrotic effect of GS on rats with liver fibrosis.Conclusion GS has certain inhibitory effect on DEN-induced liver fibrosis in rats,and its mechanism may be related to the reduction of oxidative stress level and the inhibition of the activation of TGF-β1/Smad3 signaling pathway.

Objective To explore the inhibitory effect of guggulsterone(GS)on diethylnitrosamine(DEN)-induced liver fibrosis in rats and its mechanism.Methods DEN-induced liver fibrosis model was established in SD rats.The successful model rats were randomly divided into model group(n=6),GS group(n=6,50 mg/kg,intraperitoneal injection for 4 weeks),GS+SRI group(n=6,50 mg/kg+30 mg/kg,intraperitoneal injection for 4 weeks),and control group(n=6,without DEN-induced).Rats in the control group and the model group were injected with the same amount of normal saline.The pathological changes of the liver were detected by HE staining.Serum liver function indexes including alanine aminotransferase(ALT),aspartate aminotransferase(AST),albumin(ALB)and alkaline phosphatase(ALP)were detected by automatic biochemical analyzer.The serum levels of pro-collagen Ⅲ(PC-Ⅲ),collagen Ⅳ(Ⅳ-C),hyaluronidase(HA),laminin(LN),malondialdehyde(MDA),reduced glutathione(GSH),superoxide dismutase(SOD),and catalase(CAT)were detected by ELISA assay.The mRNA and protein expression of TGF-β1,Smad2,and p-Smad3/Smad3 were detected by Real-time PCR and Western blotting.Results Compared with the control group,the model group showed typical pathological changes of liver fibrosis;the serum ALB,GSH,SOD and CAT levels were significantly decreased(P＜0.05);the serum levels of ALT,AST,ALP,MDA,PC-Ⅲ,Ⅳ-C,HA,LN and the mRNA expression of TGF-β1,Smad3 and protein expression of TGF-β1,p-Smad3 in liver tissues were significantly increased(P＜0.05).Compared with the model group,the pathological changes of liver fibrosis in the GS group were alleviated,and the serum levels of ALB,GSH,SOD and CAT were significantly increased(P＜0.05),the serum levels of ALT,AST,ALP,MDA,PC-Ⅲ,Ⅳ-C,HA and LN,the mRNA expression of TGF-β1 and Smad3,and protein expression of TGF-β1 and p-Smad3 in liver tissues were significantly decreased(P＜0.05).In addition,after the administration of SRI,TGF-β1 signaling pathway activator,compared with the GS group,the GS+SRI group showed significantly decreased serum ALB,GSH,SOD and CAT levels(P＜0.05),but significantly increased serum levels of ALT,AST,ALP,MDA,PC-Ⅲ,Ⅳ-C,HA and LN as well as the mRNA expression of TGF-β1 and Smad3 and protein expression of TGF-β1 and p-Smad3 in liver tissues(P＜0.05).Therefore,SRI attenuated the anti-fibrotic effect of GS on rats with liver fibrosis.Conclusion GS has certain inhibitory effect on DEN-induced liver fibrosis in rats,and its mechanism may be related to the reduction of oxidative stress level and the inhibition of the activation of TGF-β1/Smad3 signaling pathway.

β-glucosidase has important applications in food, pharmaceutics, biomass conversion and other fields, exploring β-glucosidase with strong adaptability and excellent properties thus has received extensive interest. In this study, a novel glucosidase from the GH1 family derived from Cuniculiplasma divulgatum was cloned, expressed, and characterized, aiming to find a better β-glucosidase. The amino acid sequences of GH1 family glucosidase derived from C. divulgatum were obtained from the NCBI database, and a recombinant plasmid pET-30a(+)-CdBglA was constructed. The recombinant protein was induced to express in Escherichia coli BL21(DE3). The enzymatic properties of the purified CdBglA were studied. The molecular weight of the recombinant CdBglA was 56.0 kDa. The optimum pH and temperature were 5.5 and 55 ℃, respectively. The enzyme showed good pH stability, 92.33% of the initial activity could be retained when treated under pH 5.5-11.0 for 1 h. When pNPG was used as a substrate, the kinetic parameters K_m, V_max and K_cat/K_m were 0.81 mmol, 291.99 μmol/(mg·min), and 387.50 s^-1 mmol^-1, respectively. 90.33% of the initial enzyme activity could be retained when CdBglA was placed with various heavy metal ions at a final concentration of 5 mmol/L. The enzyme activity was increased by 28.67% under 15% ethanol solution, remained unchanged under 20% ethanol, and 43.68% of the enzyme activity could still be retained under 30% ethanol. The enzyme has an obvious activation effect at 0-1.5 mol/L NaCl and can tolerate 0.8 mol/L glucose. In conclusion, CdBglA is an acidic and mesophilic enzyme with broad pH stability and strong tolerance to most metal ions, organic solvents, NaCl and glucose. These characteristics may facilitate future theoretical research and industrial production.
beta-Glucosidase ; Sodium Chloride ; Temperature ; Glucose ; Ethanol/chemistry* ; Ions ; Hydrogen-Ion Concentration ; Enzyme Stability ; Substrate Specificity

The cold source system of a nuclear power plant, as important part of a nuclear power project, is of great significance to guarantee the safe operation of a nuclear power plant. In recent years, there have been some cases of marine organism blockage at cold source intake at coastal nuclear power plants in China, which has adversely affected the safety and economy of nuclear power plants. According to the research result of cold source safety in coastal nuclear power plants in China and in compliance with the requirements of nuclear safety regulatory control and the engineering practice experience, the causes of, and countermeasures against, marine organism blockage at cold source intake are analyzed to further improve the safety and economy of nuclear power plants.

β-glucosidase has important applications in food, medicine, biomass conversion and other fields. Therefore, exploring β-glucosidase with strong stability and excellent properties is a research hotspot. In this study, a GH3 family β-glucosidase gene named Iubgl3 was successfully cloned from Infirmifilum uzonense. Sequence analysis showed that the full length of Iubgl3 was 2 106 bp, encoding 702 amino acids, with a theoretical molecular weight of 77.0 kDa. The gene was cloned and expressed in E. coli and the enzymatic properties of purified IuBgl3 were studied. The results showed that the optimal pH and temperature for pNPG hydrolysis were 5.0 and 85 ℃, respectively. The enzyme has good thermal stability, and more than 85% of enzyme activity can be retained after being treated at 80 ℃ for2 h. This enzyme has good pH stability and more than 85% of its activity can be retained after being treated at pH 4.0-11.0 for 1 h. It was found that the enzyme had high hydrolysis ability to p-nitrophenyl β-d-glucoside (pNPG) and p-nitrophenyl β-d-xylopyranoside (pNPX). When pNPG was used as the substrate, the kinetic parameters K_m and V_max were 0.38 mmol and 248.55 μmol/(mg·min), respectively, and the catalytic efficiency k_cat/K_m was 6 149.20 s^-1mmol^-1. Most metal ions had no significant effect on the enzyme activity of IuBgl3. SDS completely inactivated the enzyme, while EDTA increased the enzyme activity by 30%. This study expanded the β-glucosidase gene diversity of the thermophilic archaea GH3 family and obtained a thermostable acid bifunctional enzyme with good industrial application potential.
beta-Glucosidase/chemistry* ; Archaea/metabolism* ; Escherichia coli/metabolism* ; Hydrogen-Ion Concentration ; Temperature ; Glucosides ; Enzyme Stability ; Substrate Specificity ; Kinetics