Objective To investigate the impact of various levels of sublethal temperature （26℃, 31 ℃, 33℃, 36℃, and 39℃） on growth and heat shock protein （hsp） expression in freshwater green alga Scenedesmus quadricauda...Objective To investigate the impact of various levels of sublethal temperature （26℃, 31 ℃, 33℃, 36℃, and 39℃） on growth and heat shock protein （hsp） expression in freshwater green alga Scenedesmus quadricauda. Methods Impact of selected levels of temperature on growth rate （based on optical density）, population count, chlorophyll-a and biomass of the alga was evaluated in artificial growth medium for 19 days. To determine the induction of hsp in the alga, it was exposed to selected temperature levels for 3 h and further kept for 6 h at culturing condition at 26℃. Induction of hsp was confirmed by immuno-detection followed by SDS-polyacrylamide gel electrophoresis. Results The selected growth parameters such as growth rate, population count, chlorophyll-a and biomass were reduced significantly （P〈0.001） at 39℃. However, hsp 70 expression was observed only at 39℃. Conclusion Temperature up to 36℃ may be considered as the limit of safe exposure for thermal, stress for the alga Scenedesmus quadricauda.展开更多
基金This work was financially supported by Board of Research in Nuclear Sciences (BRNS sanction No. 99/36/23/BRNS/1869),Department of Atomic Energy, Government of India.
文摘Objective To investigate the impact of various levels of sublethal temperature （26℃, 31 ℃, 33℃, 36℃, and 39℃） on growth and heat shock protein （hsp） expression in freshwater green alga Scenedesmus quadricauda. Methods Impact of selected levels of temperature on growth rate （based on optical density）, population count, chlorophyll-a and biomass of the alga was evaluated in artificial growth medium for 19 days. To determine the induction of hsp in the alga, it was exposed to selected temperature levels for 3 h and further kept for 6 h at culturing condition at 26℃. Induction of hsp was confirmed by immuno-detection followed by SDS-polyacrylamide gel electrophoresis. Results The selected growth parameters such as growth rate, population count, chlorophyll-a and biomass were reduced significantly （P〈0.001） at 39℃. However, hsp 70 expression was observed only at 39℃. Conclusion Temperature up to 36℃ may be considered as the limit of safe exposure for thermal, stress for the alga Scenedesmus quadricauda.
文摘城镇污水中的碳、氮、磷等污染物主要是采用微生物法进行去除,需通过曝气、补碳等方法保证出水达标。藻菌共生体系是利用微藻产氧气驱动硝化过程去除氨氮,减少曝气成本,并且促进藻菌形成絮体,提高沉降性能。实验结果表明,当光暗比为18 h:6 h时,藻菌系统对氨氮的去除率最高达到82.57%,此时叶绿素a浓度和叶绿素荧光参强度Fv/Fm最高,分别为112.54μg/L和0.53。此外,扫描电子显微镜(Scanning Electron Microscope,SEM)结果显示,相较于单独污泥系统,藻菌体系中形成紧密的絮体结构,提高了藻菌沉降性能。
