Optimization of Douchi fibrinolytic enzyme production by statistical experimental methods / 华中科技大学学报（医学）（英德文版）

Thrombus disease, one of the common cardiovascular diseases, has attracted worldwide attention for its rising mortality and morbidity. Due to the distinct shortages of current fibrinolytic drugs, new fibrinolytic agents warrant investigation. In this study, 8 fibrinolytic enzyme-producing strains were isolated from Douchi-a traditional Chinese food, and strain XY-1 which produced the largest amount of the enzyme was chosen for the following experiments. The enzyme produced by strain XY-1 was named Douchi fibrinolytic enzyme (DFE). We optimized the liquid culture medium of strain XY-1 for enzyme production using Plackett-Burman and Box-Behnken design. The predicted maximal DFE yield was 19.78 FU/mL with 11.4 g/L peptone, 0.5 g/L magnesium sulfate and 1 g/L sodium chloride. However, we acquired maximal production of 21.33 FU/mL in actual experiments, equal to 107.84% of the theoretical value, and the yield had been increased by 79.55% as compared to the yield of un-optimized culture. It was demonstrated that the combined use of Plackett-Burman design and response surface methodology in fermentation optimization can effectively and rapidly increase DFE production.

Optimization of Douchi fibrinolytic enzyme production by statistical experimental methods / 华中科技大学学报（医学）（英德文版）

Thrombus disease, one of the common cardiovascular diseases, has attracted worldwide attention for its rising mortality and morbidity. Due to the distinct shortages of current fibrinolytic drugs, new fibrinolytic agents warrant investigation. In this study, 8 fibrinolytic enzyme-producing strains were isolated from Douchi-a traditional Chinese food, and strain XY-1 which produced the largest amount of the enzyme was chosen for the following experiments. The enzyme produced by strain XY-1 was named Douchi fibrinolytic enzyme (DFE). We optimized the liquid culture medium of strain XY-1 for enzyme production using Plackett-Burman and Box-Behnken design. The predicted maximal DFE yield was 19.78 FU/mL with 11.4 g/L peptone, 0.5 g/L magnesium sulfate and 1 g/L sodium chloride. However, we acquired maximal production of 21.33 FU/mL in actual experiments, equal to 107.84% of the theoretical value, and the yield had been increased by 79.55% as compared to the yield of un-optimized culture. It was demonstrated that the combined use of Plackett-Burman design and response surface methodology in fermentation optimization can effectively and rapidly increase DFE production.

Effects of the Three Gorges project and change of water level on local mouse density / 中国地方病学杂志

Objective To study the impacts of the Three Gorges dam and change of water level on the survival of the local rodents, and to provide scientific basis to control the outbreak of rodent-borne diseases.Methods Four villages located around the Three Gorges dam were selected in the study. The mouse populations by using Elton night trapping method was monitored. Metallic spring traps were set for two consecutive nights. The mouse density and identified the mouse species was calculated. The mouse species indoor and outdoor, as well as the mouse density indoor and outdoor were compared. The impacts of water level in the dam and cleaning work on local mouse density were also analyzed. Results A total of 678 mice were caught in this study, 517 were caught indoor and 161 outdoor. Indoor dominant species was flavipectus; accounting for 36.49%(189/517), while outdoor was apodemus, reaching 56.88% (91/161). For mouse species, there was a significant difference between indoor and outdoor(x2 = 678.00, P ＜ 0.01 ). The average mouse density was 8.44%(678/8036) in trap nights. Indoor mouse density reached 14.44%(517/3581 ), which was significantly higher than that of outdoor(3.61%, 161/4455 ).For mouse density, there was a significant difference between indoor and outdoor(x2 = 301.04, P ＜ 0.01 ). When the water level was up to 156 m, mouse density reached 10%(513/5132), which was higher than that of before (5.68%, 165/2904). There was a significant difference in mouse density before and after reserving water (x2 = 44.68, P ＜ 0.01 ). With the change of water level, upstream mouse density formed a high platform from May 2007 to May 2008, followed by 12.25%(80/653), 13.16%(90/684), 12.95%(90/695), and decreased to 8.38%(28/334) after cleaning of the dam. Conclusions The Three Gorges dam and change of water level actually alter the survival environment of the local mouse, and affect local mouse density and mouse species. These may lead to local outbreak or epidemic of rodent-borne diseases.