Advances in microbial enzymatic elimination of ethyl carbamate in Chinese rice wine / 生物工程学报

Ethyl carbamate (EC), a carcinogenic and teratogenic chemical that is widely distributed in various alcoholic beverages, has attracted much attention. Microbial enzymatic degradation of EC in rice wine is always efficient and attractive. In this review, we summarize the research progress and problems of microbial enzymatic elimination of EC in rice wine from three aspects: the mechanisms of EC formation in rice wine, the research progress of acid urease, and the research progress of urethanase. Then, we propose the corresponding strategies to solve the problems: screening new urethanase with satisfied enzyme properties, food-grade expression and directed evolution of the bifunctional Fe³⁺-dependent acid urease and acid urease used in combination with urethanase to eliminate both urea and EC in rice wine.

Identification of determinants that mediate binding between Tembusu virus and the cellular receptor heat shock protein A9

Heat shock protein A9 (HSPA9), a member of the heat shock protein family, is a putative receptor for Tembusu virus (TMUV). By using Western blot and co-immunoprecipitation assays, E protein domains I and II were identified as the functional domains that facilitate HSPA9 binding. Twenty-five overlapping peptides covering domain I and domain II sequences were synthesized and analyzed by using an HSPA9 binding assay. Two peptides showed the capability of binding to HSPA9. Dot blot assay of truncated peptides indicated that amino acid residues 19 to 22 and 245 to 252 of E protein constitute the minimal motifs required for TMUV binding to HSPA9. Importantly, peptides harboring those two minimal motifs could effectively inhibit TMUV infection. Our results provide insight into TMUV-receptor interaction, thereby creating opportunities for elucidating the mechanism of TMUV entry.

Degradation of urea and ethyl carbamate in Chinese Rice wine by recombinant acid urease / 生物工程学报

Ethyl carbamate (EC) as a potential carcinogen commonly exists in traditional fermented foods. It is important eliminate urea that is the precursors of EC in many fermented foods, including Chinese Rice wine. On the basis of achieving high-level overexpression of food-grade ethanol-resistant acid urease, we studied the hydrolysis of urea and EC with the recombinant acid urease. Recombinant acid urease showed degraded urea in both the simulated system with ethanol and Chinese Rice wine (60 mg/L of urea was completely degraded within 25 h), indicating that the recombinant enzyme is suitable for the elimination of urea in Chinese Rice wine. Although recombinant acid urease also has degradation catalytic activity on EC, no obvious degradation of EC was observed. Further investigation results showed that the Km value for urea and EC of the recombinant acid urease was 0.7147 mmol/L and 41.32 mmol/L, respectively. The results provided theoretical foundation for realizing simultaneous degradation of urea and EC.

Improving Effect of Total Flavone from Litchi chinensis on the Hepatocyte Injury in Liver Fibrosis Model Rats / 中国药房

OBJECTIVE:To study the improving effect of total flavone from Litchi chinensis (TFL) on the hepatocyte injury in rats with liver fibrosis. METHODS:The rats were given dimethylnitrosamine(DMN),ip,once a day in the first 3 d of every week,which lasted for 30 consecutive days to establish hepatocyte injury model. 60 rats were equally randomized into a normal control(isometric normal saline)group,a model(isometric normal saline)group and the groups of high and low-dose TFL(200 and 100 mg/kg). When the model was being established,drugs were administered,ig,once a day for 45 consecutive days except for normal control group. HE staining was performed,and then the rats’hepatocytes were observed under the microscope and path-ological stage (S1-S4) of liver tissue was analyzed. Masson staining and immunohistochemical staining were conducted,and then the rats’hepatocytes were observed under the microscope and calculation was made for the degree of liver fibrosis and the expres-sion of Bcl-2 and Bax. The activities of aspartate aminotransferase(AST)and alanine aminotransferase(ALT)in rats’serum were determined. RESULTS:The pathological stages of liver cell of rats in the model group were mainly stages S3 and S4 and the groups of high and low doses TFL were dominated by stages S1 and S2. Compared to the rats in the normal control group,those in the mod-el group had higher degree of liver fibrosis,expression of Bcl-2 and Bax and activities of AST and ALT in serum. Compared to the rats in the model group,those in the groups of high and low doses TFL had lower degree of liver fibrosis,higher expression of Bcl-2,lower expression of Bax,and lower activities of AST and ALT in serum. There were statistically significance (P<0.05). CONCLUSIONS:TFL can alleviate the hepatocyte injury in rats with liver fibrosis to some degree by a mechanism which may be related to the up-regulation the expression of Bcl-2 and the down-regulation of the expression of Bax.

β-amyloid protein up-regulates the expression of the receptor for advanced glycation end products by increasing ROS production / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the mechanism of β-amyloid protein (Aβ) in regulating the expression of the receptor for advanced glycation end products (RAGE).</p><p><b>METHODS</b>Aβ1-40 was injected into the bilateral hippocampus of rats, and 3 weeks later, the levels of reactive oxygen species (ROS) production were detected by flow cytometry. The expressions of RAGE, reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (gp9l(phox) and p47(phox)), nuclear factor-κB (NF-κB), and inhibitor of κB (IκB) were measured by Western blotting.</p><p><b>RESULTS</b>Injection of Aβ1-40 caused a significant increase in the expressions of RAGE, gp9l(phox), p47(phox), phospho-p47(phox), phospho-IκBα, NF-κB and phospho-NF-κB in rat hippocampus but decreased the level of IκBα. Aβ1-40 injection also resulted in a significantly increased content of ROS in the hippocampus of the rats.</p><p><b>CONCLUSION</b>Aβ up-regulates the expression of RAGE in rat hippocampus via NADPH/ ROS/NF-κB signaling pathway.</p>

Application of CT simulation for nasopharyngeal carcinoma conventional radiotheraphy / 肿瘤研究与临床

Objective To compare and observe the effect and side effect of two different kinds of simulation mode for nasopharyngeal carcinoma conventional radiotherapy. Methods 147 cases were randomly divided into the study group (74 cases, CT simulation) and the control group (73 cases, X-ray radiography simulation). In the study group three-dimensional treatment planning system (IPS) was used to draw target volume and organ at risk, and then beam eye view (BEV) function was utilized to design treatment plan and subsequent plan modulation. In the control group X-ray simulation radiography was used. Two groups of plan design and subsequent plan modulation mode were exactly the same, and the radiotherapy were performed on the same accelerator. Results For these two groups, there were 5-59 months follow-up. The recent therapeutic effect of nasopharyngeal carcinoma primary site and cervical lymph node metastasis was regular,and no statistical significance (P >0.05). For the study group 3-year local recurrence rate was 5.4 % (4/74) while the control group was 16.4 %(12/73), and there was obvious statistical significance between two groups. About one year and three year accumulated survival rate, the study group was 98.5 %, 77.4 %, and for the control group was 92.9 %, 64.7 %. Two groups survival curves were examined by Log-rank test: the survival curves showed statistical significance between two groups(P <0.05). In control group, stage II and III radiotheray reaction of oralis mucosa was significantly increased compared with that of the study group (P < 0.05). There were two cases radioactivity cerebral palsy and one case optic nerve damage in the control group, but no serious dermatosis, soft tissue fibrosis and radioactivity posterior cranial nerve damage. Conclusion The CT simulation which is applied to nasopharyngeal carcinoma conventional radiotheraphy could improve therapeutic effect and reduce cancer recurrence and radiation side effect.