根系可分泌表达枯草芽孢杆菌纤溶酶B a c illu s s u b tilis f i b r i n o l y t i c e n z y m e,B S F E的转基因烟草在0、8、16和24h的光照条件下,在25℃、30℃和昼30℃鲆?25℃、16h?8h光暗培养条件下和通气与不通气的水培处理下,...根系可分泌表达枯草芽孢杆菌纤溶酶B a c illu s s u b tilis f i b r i n o l y t i c e n z y m e,B S F E的转基因烟草在0、8、16和24h的光照条件下,在25℃、30℃和昼30℃鲆?25℃、16h?8h光暗培养条件下和通气与不通气的水培处理下,其水培液B S F E活性呈抛物线型变化趋势.延长光照时间可加快其根系向水培液中分泌B S F E,峰值出现提前,但培养后期水培液B S F E活性急剧降低.四个时间处理相比,8、16h光照处理能维持该转基因烟草根系B S F E分泌的较高水平.建议生产中使用16h以上光照培养,适当缩短培养液更新周期,以8～10d为宜.昼30℃鲆?25℃培养条件下水培液B S F E活性在峰值出现前介于30℃和25℃培养条件之间,而峰值出现后则高于30℃和25℃培养条件,说明温度对器官生长、代谢的影响是造成3种温度处理下水培液B S F E活性差异的主要原因.通气处理可提高该转基因烟草根系B S F E的分泌水平.但在1～15d的培养期内,通气处理与不通气处理间不存在显著差异.这说明通气处理对短时间培养并不必要.展开更多
The seed germination and tomato seedling tests showed that Bacillus subtilis SL-13 could promote the sprouting and seedling growth of tomato.The fresh and dry weight of tomato seedlings increased 42.86%and 18.75%,resp...The seed germination and tomato seedling tests showed that Bacillus subtilis SL-13 could promote the sprouting and seedling growth of tomato.The fresh and dry weight of tomato seedlings increased 42.86%and 18.75%,respectively.The control efficacies of the SL-13 to tomato Rhizoctonia rot were 20.65%and 35.23%in the greenhouse and field,respectively.The growth of the plant-pathogenic fungus Rhizoctonia solani was considerably inhibited in the presence of the strain SL-13 culture supernatant.The main antifungal protein was detected to be chitinase through vitro assay.The chitinase was purified with DEAE-Sepharose fast flow ion exchange column chromatography and Sephadex G-75 gel filtration for further characterization.The optimal pH and temperature for the chitinase activity were 7.0 and 50°C,respectively.It was demonstrated that the enzyme was stable at pH 5-9 and 40-60°C.70%of the enzyme activity was retained when incubated at 121°C and 0.11 MPa for 20 min,and the enzyme was not sensitive to protease K and ultraviolet radiation.Thus it is suitable for effective biological control in relatively unstable environment.展开更多
The aim of this work was to construct a novel food-grade industrial arming yeast displaying β-1,3-1,4-glucanase and to evaluate the thermal stability of the glucanase for practical application. For this purpose, a bi...The aim of this work was to construct a novel food-grade industrial arming yeast displaying β-1,3-1,4-glucanase and to evaluate the thermal stability of the glucanase for practical application. For this purpose, a bi-directional vector containing galactokinase （GALl） and phosphoglycerate kinase 1 （PGK1） promoters in different orientations was constructed. The β-1,3-1,4-glucanase gene from Bacillus subtilis was fused to α-agglutinin and ex- pressed under the control of the GALl promoter, α-galactosidase induced by the constitutive PGK1 promoter was used as a food-grade selection marker. The feasibility of the α-galactosidase marker was confirmed by the growth of transformants harboring the constructed vector on a medium containing melibiose as a sole carbon source, and by the clear halo around the transformants in Congo-red plates owing to the expression of β-1,3-1,4-glucanase. The analysis of β-1,3-1,4-glucanase activity in cell pellets and in the supernatant of the recombinant yeast strain revealed that β-1,3-1,4-glucanase was successfully displayed on the cell surface of the yeast. The displayed β-1,3-1,4-glucanase activity in the recombinant yeast cells increased immediately after the addition of galactose and reached 45.1 U/ml after 32-h induction. The thermal stability of β-1,3-1,4-glucanase displayed in the recombinant yeast cells was en- hanced compared with the free enzyme. These results suggest that the constructed food-grade yeast has the potential to improve the brewing properties of beer.展开更多
文摘根系可分泌表达枯草芽孢杆菌纤溶酶B a c illu s s u b tilis f i b r i n o l y t i c e n z y m e,B S F E的转基因烟草在0、8、16和24h的光照条件下,在25℃、30℃和昼30℃鲆?25℃、16h?8h光暗培养条件下和通气与不通气的水培处理下,其水培液B S F E活性呈抛物线型变化趋势.延长光照时间可加快其根系向水培液中分泌B S F E,峰值出现提前,但培养后期水培液B S F E活性急剧降低.四个时间处理相比,8、16h光照处理能维持该转基因烟草根系B S F E分泌的较高水平.建议生产中使用16h以上光照培养,适当缩短培养液更新周期,以8～10d为宜.昼30℃鲆?25℃培养条件下水培液B S F E活性在峰值出现前介于30℃和25℃培养条件之间,而峰值出现后则高于30℃和25℃培养条件,说明温度对器官生长、代谢的影响是造成3种温度处理下水培液B S F E活性差异的主要原因.通气处理可提高该转基因烟草根系B S F E的分泌水平.但在1～15d的培养期内,通气处理与不通气处理间不存在显著差异.这说明通气处理对短时间培养并不必要.
基金Supported by the National Natural Science Foundation of China（20776017） the Xinjiang Uygur Autonomous Region High-tech Research and Development Project（20081108）+1 种基金 the Fok Ying Tung Education Foundation（101071） the Xinjiang Bingtuan Key Science and Technology Industry Project（2008GG24）
文摘The seed germination and tomato seedling tests showed that Bacillus subtilis SL-13 could promote the sprouting and seedling growth of tomato.The fresh and dry weight of tomato seedlings increased 42.86%and 18.75%,respectively.The control efficacies of the SL-13 to tomato Rhizoctonia rot were 20.65%and 35.23%in the greenhouse and field,respectively.The growth of the plant-pathogenic fungus Rhizoctonia solani was considerably inhibited in the presence of the strain SL-13 culture supernatant.The main antifungal protein was detected to be chitinase through vitro assay.The chitinase was purified with DEAE-Sepharose fast flow ion exchange column chromatography and Sephadex G-75 gel filtration for further characterization.The optimal pH and temperature for the chitinase activity were 7.0 and 50°C,respectively.It was demonstrated that the enzyme was stable at pH 5-9 and 40-60°C.70%of the enzyme activity was retained when incubated at 121°C and 0.11 MPa for 20 min,and the enzyme was not sensitive to protease K and ultraviolet radiation.Thus it is suitable for effective biological control in relatively unstable environment.
基金Project (No.2006AA10Z316) supported by the Hi-Tech Research and Development Program (863) of China
文摘The aim of this work was to construct a novel food-grade industrial arming yeast displaying β-1,3-1,4-glucanase and to evaluate the thermal stability of the glucanase for practical application. For this purpose, a bi-directional vector containing galactokinase （GALl） and phosphoglycerate kinase 1 （PGK1） promoters in different orientations was constructed. The β-1,3-1,4-glucanase gene from Bacillus subtilis was fused to α-agglutinin and ex- pressed under the control of the GALl promoter, α-galactosidase induced by the constitutive PGK1 promoter was used as a food-grade selection marker. The feasibility of the α-galactosidase marker was confirmed by the growth of transformants harboring the constructed vector on a medium containing melibiose as a sole carbon source, and by the clear halo around the transformants in Congo-red plates owing to the expression of β-1,3-1,4-glucanase. The analysis of β-1,3-1,4-glucanase activity in cell pellets and in the supernatant of the recombinant yeast strain revealed that β-1,3-1,4-glucanase was successfully displayed on the cell surface of the yeast. The displayed β-1,3-1,4-glucanase activity in the recombinant yeast cells increased immediately after the addition of galactose and reached 45.1 U/ml after 32-h induction. The thermal stability of β-1,3-1,4-glucanase displayed in the recombinant yeast cells was en- hanced compared with the free enzyme. These results suggest that the constructed food-grade yeast has the potential to improve the brewing properties of beer.
