ABSTRACT
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.
ABSTRACT
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.
Subject(s)
Humans , Bacillus , Physiology , Bioreactors , Microbiology , Blood Coagulation , Physiology , Cells, Cultured , Combinatorial Chemistry Techniques , Computer Simulation , Fabaceae , Microbiology , Fibrinolytic Agents , Metabolism , Pharmacology , Models, Biological , Models, StatisticalABSTRACT
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.
ABSTRACT
<p><b>OBJECTIVE</b>To study the possibility of removing nitrogen, phosphorus, and organic pollutants using seeding type immobilized microorganisms.</p><p><b>METHODS</b>Lakes P and M in Wuhan were chosen as the objects to study the removal of nitrogen, phosphorus, and organic pollutants with the seeding type immobilized microorganisms. Correlations between the quantity of heterotrophic bacteria and the total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) in the two lakes were studied. The dominant bacteria were detected, inoculated to the sludge and acclimated by increasing nitrogen, phosphorus and decreasing carbon source in an intermittent, time-controlled and fixed-quantity way. The bacteria were then used to prepare the seeding type immobilized microorganisms, selecting diatomite as the adsorbent carrier. The ability and influence factors of removing nitrogen, phosphorus, and organic pollutant from water samples by the seeding type immobilized microorganisms were studied.</p><p><b>RESULTS</b>The coefficients of the heterotrophic bacterial quantity correlated with TOC, TP, and TN were 0.9143, 0.8229, 0.7954 in Lake P and 0.9168, 0.7187, 0.6022 in Lake M. Ten strains of dominant heterotrophic bacteria belonging to Pseudomonas, Coccus, Aeromonas, Bacillus, and Enterobateriaceae, separately, were isolated. The appropriate conditions for the seeding type immobilized microorgansims in purifying the water sample were exposure time=24 h, pH=7.0-8.0, and quantity of the immobilized microorganisms=0.75-1 g/50 mL. The removal rates of TOC, TP, and TN under the above conditions were 80.2%, 81.6%, and 86.8%, respectively.</p><p><b>CONCLUSION</b>The amount of heterotrophic bacteria in the two lakes was correlated with TOC, TP, and TN. These bacteria could be acclimatized and prepared for the immobilized microorganisms which could effectively remove nitrogen, phosphorus, and mixed organic pollutants in the water sample.</p>