UV-B-induced oxidative damage and the protective effect of exopolysaccharides （EPS） in Microcoleus vaginatus, a cyanobacterium isolated from desert crust, were investigated. After being irradiated with UV-B radiatio...UV-B-induced oxidative damage and the protective effect of exopolysaccharides （EPS） in Microcoleus vaginatus, a cyanobacterium isolated from desert crust, were investigated. After being irradiated with UV-B radiation, photosynthetic activity （FvlFm）, cellular total carbohydrates, EPS and sucrose production of irradiated cells decreased, while reducing sugars, reactive oxygen species （ROS） generation, malondialdehyde （MDA） production and DNA strand breaks increased significantly. However, when pretreated with 100 mg/L exogenous EPS, EPS production in the culture medium of UVo B stressed cells decreased significantly; Fv/Fm, cellular total carbohydrates, reducing sugars and sucrose synthase （SS） activity of irradiated cells increased significantly, while ROS generation, MDA production and DNA strand breaks of irradiated cells decreased significantly. The results suggested that EPS exhibited a significant protective effect on DNA strand breaks and lipid peroxidation by effectively eliminating ROS induced by UV-B radiation in M. vaginatus.展开更多
In arid and semiarid areas,water uptake (non-rainfall water) serves as an important water source for plants,biological soil crusts,insects and small animals.In this study,a measurement program was undertaken to invest...In arid and semiarid areas,water uptake (non-rainfall water) serves as an important water source for plants,biological soil crusts,insects and small animals.In this study,a measurement program was undertaken to investigate water uptake and its changes during formation of man-made algal crusts in the Qubqi Desert.In the study region,water uptake from the atmosphere accounted for 25.07%-39.83% of the total water uptake,and was mainly taken up by a water vapor adsorption mechanism;the proportion of water uptake from the soil substrate was much higher (60.17%-74.93%).The formation of crusts promoted water uptake,but the increased uptake did not occur immediately after inoculation or crusts formation.The water taken up from the atmosphere increased significantly from day 15 after inoculation,and the soil water content was markedly enhanced from day 20 after inoculation.It is considered that the growth of algal filaments and their secretions were the main factors increasing the amount of water uptake and water content in the crusts,and these variables increased even during dry periods when some algae are likely to have died.展开更多
【目的】从新疆的典型干旱荒漠生境中分离出具有一定生物学特性的微藻品系,进行鉴定及分析特性。【方法】扫描电镜和光学显微镜确定细胞形态,并用18S r DNA分子标记方法对此品系进行初步鉴定。XLD-9品系培养在BBM液体培养基上并在此培...【目的】从新疆的典型干旱荒漠生境中分离出具有一定生物学特性的微藻品系,进行鉴定及分析特性。【方法】扫描电镜和光学显微镜确定细胞形态,并用18S r DNA分子标记方法对此品系进行初步鉴定。XLD-9品系培养在BBM液体培养基上并在此培养条件下确定最佳p H条件,重金属(Cd2+、Ag+、Hg2+)和抗生素(素氯霉素、四环素、链霉素)抗性最佳浓度和生长最高耐受浓度。在BBM固体培养基上培养确定Na Cl抗性最佳浓度和生长耐受浓度。【结果】据18S r DNA分析结果将XLD-9鉴定为Marvania geminata;其细胞近球形,个体较小;属嗜碱性微藻,p H 12.0的培养基中能正常生长。对重金属有一定的抗性,Cd2+的抗性达0.333 Mm。对氯霉素和四环素有很好的抗性,分别为41.7与60μg/m L,但对链霉素敏感。对盐的抗性已到400 m M,超过了模式生物的莱茵衣藻CC-124突变株抗性范围(350 m M)。【结论】从沙漠土壤中分离得到的微藻品系XLD-9,表现出对抗生素、Na Cl显著的抗性,并能在p H 12.0的环境内生长,在抗盐基因的筛选及盐化土壤的治理方面有一定利用价值。展开更多
基金Supported by the National Natural Science Foundation of China (30500068,30570343)National Hi-Tech Research and Development Program of China(863) (2005AA601010-02-2)Water Environment Research & Data Sharing Platform in the Middle Reaches of the Yangtze River (Wuhan University,WERDSPMYR-0605)
文摘UV-B-induced oxidative damage and the protective effect of exopolysaccharides （EPS） in Microcoleus vaginatus, a cyanobacterium isolated from desert crust, were investigated. After being irradiated with UV-B radiation, photosynthetic activity （FvlFm）, cellular total carbohydrates, EPS and sucrose production of irradiated cells decreased, while reducing sugars, reactive oxygen species （ROS） generation, malondialdehyde （MDA） production and DNA strand breaks increased significantly. However, when pretreated with 100 mg/L exogenous EPS, EPS production in the culture medium of UVo B stressed cells decreased significantly; Fv/Fm, cellular total carbohydrates, reducing sugars and sucrose synthase （SS） activity of irradiated cells increased significantly, while ROS generation, MDA production and DNA strand breaks of irradiated cells decreased significantly. The results suggested that EPS exhibited a significant protective effect on DNA strand breaks and lipid peroxidation by effectively eliminating ROS induced by UV-B radiation in M. vaginatus.
基金supported by the National Natural Science Foundation of China (Grant Nos. 30770395 and 30870470)partly by the Wuhan Science and Technology Bureau and the Inner Mongolia Planning Committee on high-tech industrialization
文摘In arid and semiarid areas,water uptake (non-rainfall water) serves as an important water source for plants,biological soil crusts,insects and small animals.In this study,a measurement program was undertaken to investigate water uptake and its changes during formation of man-made algal crusts in the Qubqi Desert.In the study region,water uptake from the atmosphere accounted for 25.07%-39.83% of the total water uptake,and was mainly taken up by a water vapor adsorption mechanism;the proportion of water uptake from the soil substrate was much higher (60.17%-74.93%).The formation of crusts promoted water uptake,but the increased uptake did not occur immediately after inoculation or crusts formation.The water taken up from the atmosphere increased significantly from day 15 after inoculation,and the soil water content was markedly enhanced from day 20 after inoculation.It is considered that the growth of algal filaments and their secretions were the main factors increasing the amount of water uptake and water content in the crusts,and these variables increased even during dry periods when some algae are likely to have died.
文摘【目的】从新疆的典型干旱荒漠生境中分离出具有一定生物学特性的微藻品系,进行鉴定及分析特性。【方法】扫描电镜和光学显微镜确定细胞形态,并用18S r DNA分子标记方法对此品系进行初步鉴定。XLD-9品系培养在BBM液体培养基上并在此培养条件下确定最佳p H条件,重金属(Cd2+、Ag+、Hg2+)和抗生素(素氯霉素、四环素、链霉素)抗性最佳浓度和生长最高耐受浓度。在BBM固体培养基上培养确定Na Cl抗性最佳浓度和生长耐受浓度。【结果】据18S r DNA分析结果将XLD-9鉴定为Marvania geminata;其细胞近球形,个体较小;属嗜碱性微藻,p H 12.0的培养基中能正常生长。对重金属有一定的抗性,Cd2+的抗性达0.333 Mm。对氯霉素和四环素有很好的抗性,分别为41.7与60μg/m L,但对链霉素敏感。对盐的抗性已到400 m M,超过了模式生物的莱茵衣藻CC-124突变株抗性范围(350 m M)。【结论】从沙漠土壤中分离得到的微藻品系XLD-9,表现出对抗生素、Na Cl显著的抗性,并能在p H 12.0的环境内生长,在抗盐基因的筛选及盐化土壤的治理方面有一定利用价值。
