| In eutrophic water, the algal blooms has bring a great threat to the water body ecosystems safety and even human life. Microcystis bloom is the most common of algal bloom, Microcystis has a unique mechanism and physiological characteristics to adapt to environmental change,can quickly grow and gain dominance status of the water environment. Microcystis populations in the water often form colony, to obtain and maintain its morphology has been a very positive factor for getting the dominant position in the water. However, the formation mechanism of colonies of microcystis is known little so this study focus on the formation of colony and the relationship with intergrouth bacterial. At the same time,as Microcystis obtain from Poyang Lake(representative species in cyanobacterial blooms), search for the method of separation, purification and identification of microcystin, while trying to take advantage of the research group looking algal aspects potent compound and analyzed their effectiveness and subsequent security. The main results are as follows:1. The bacterial diversities analyze by DGGE show that Deinococcus sp.,Actinobacteridae sp. belong to the surrounding formation period in the presence of special groups, but after six month cultivate,the bacteria intergrouth with the colony which has disaggregated is same to the unicellular.Such results indicate that bacteria intergrouth with these two morphopy play a specific role of M. aeruginosa CHAB5067 may be indispensable to maintain the colony morphology of biological factors.2. By counting the algal cells and bacteria quantity and measure the volume of colony has found that bacteria produce certain groups of algae growth inhibition,while the latter two groups of bacteria disappear, slow-growing populations of Microcystis accelerated growth trend. After determination b EPS(extracellular binding polysaccharides) content of colony show that significantly higher than the unicelluar morphology, reaching 2.63pg/cell, while the nuicelluar only 1.55 pg/cell, but later the two polysaccharide content trend to the same, respectively was 1.52 pg/cell, 1.46pg/cell, plays a decisive role in the description of colony morphology maintain species secrete polysaccharides.3.After several toxins extraction and analysis test,we obtain the method asfollow: 70% methanol/ water ratio solution is the best extraction solvent for microcystin; the volume of 70% methanol and dry weight of microcystis ratio is 50:1,magnetic stirring extraction time 1h ultrasonic shock for 30 min, centrifuged at 8000 r /min for 20 min optimum method for microcystin toxin extracting,can obtain less impurities microcystin crude. Then the crude product was purified by preparative column were analyzed: 20-40% maximum concentration of methanol in addition to impurities, after elution by 70% methanol, the microcystin can eluted and gain the pure ones. By HPLC analysis found that the peak time was consistent with standard MC-LR. While the purified product by LC-MS analysis shows that microcystin toxins ion peak of M.aeruionga CHAB5067 is consistent with standard products MC-LR,thus confirming the microcytin is MC-LR.4.Our research group put attention on looking for the algal inhibitor CMQ that can strongly inhibit the growth of M.aeruionga CHAB5067 and the microcytin production the research results are as follows: CMQ can inhibit the growth of unicellular M.aeruionga CHAB5067, and has a "concentration effect", and has impact on the content of chlorophyll a. Then by assaying the content of microcytin, found that 10mg/L, 5mg/Lcontent of CMQ can respectively reduce 68% and 20%production of microcytin, apparent simultaneous high concentrations can inhibit the growth of algae can reduce toxin production reduce the harmful to the environment. |
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