As a unique ecological system with low temperature and low nutrient levels, glaciers are considered a "living fossil" for the research of evolution. In this work, a lytic cold-active bacteriophage designated...As a unique ecological system with low temperature and low nutrient levels, glaciers are considered a "living fossil" for the research of evolution. In this work, a lytic cold-active bacteriophage designated VMY22 against Bacillus cereus MYB41-22 was isolated from Mingyong Glacier in China, and its characteristics were studied. Electron microscopy revealed that VMY22 has an icosahedral head(59.2 nm in length, 31.9 nm in width) and a tail(43.2 nm in length). Bacteriophage VMY22 was classified as a Podoviridae with an approximate genome size of 18 to 20 kb. A one-step growth curve revealed that the latent and the burst periods were 70 and 70 min, respectively, with an average burst size of 78 bacteriophage particles per infected cell. The pH and thermal stability of bacteriophage VMY22 were also investigated. The maximum stability of the bacteriophage was observed to be at pH 8.0 and it was comparatively stable at p H 5.0–9.0. As VMY22 is a cold-active bacteriophage with low production temperature, its characterization and the relationship between MYB41-22 and Bacillus cereus bacteriophage deserve further study.展开更多
Dioxygen activations constitute one of core issues in copper-dependent metalloenzymes. Upon O_(2) activation, copper-dependent metalloenzymes such as particulate methane monooxygenases(pM MOs), lytic polysaccharide mo...Dioxygen activations constitute one of core issues in copper-dependent metalloenzymes. Upon O_(2) activation, copper-dependent metalloenzymes such as particulate methane monooxygenases(pM MOs), lytic polysaccharide monooxygenases(LPMOs) and binuclear copper enzymes PHM and DβM, are able to perform various challenging C–H bond activations. Meanwhile, various copper-oxygen core containing complexes have been synthetized to mimic the active species of metalloenzymes. Dioxygen activation by mononuclear copper active site may generate various copper-oxygen intermediates, including Cu(Ⅱ)-superoxo, Cu(Ⅱ)-hydroperoxo, Cu(Ⅱ)-oxyl as well as the Cu(Ⅲ)-hydroxide species. Intriguingly, all these species have been invoked as the potential active intermediates for C–H/O–H activations in either biological or synthetic systems. Due to the poor understanding on reactivities of copper-oxygen complex, the nature of active species in both biological and synthetic systems are highly controversial. In this account, we will compare the reactivities of various mononuclear copper-oxygen species between biological systems and the synthetic systems. The present study is expected to provide the consistent understanding on reactivities of various copper-oxygen active species in both biological and synthetic systems.展开更多
基金supported by the National Natural Science Foundation of China (31160121)the Yunnan Provincial Education Fund project (2013Z138)funded by the Open Research Fund Program of the State Key Laboratory of Virology of China (2013002)
文摘As a unique ecological system with low temperature and low nutrient levels, glaciers are considered a "living fossil" for the research of evolution. In this work, a lytic cold-active bacteriophage designated VMY22 against Bacillus cereus MYB41-22 was isolated from Mingyong Glacier in China, and its characteristics were studied. Electron microscopy revealed that VMY22 has an icosahedral head(59.2 nm in length, 31.9 nm in width) and a tail(43.2 nm in length). Bacteriophage VMY22 was classified as a Podoviridae with an approximate genome size of 18 to 20 kb. A one-step growth curve revealed that the latent and the burst periods were 70 and 70 min, respectively, with an average burst size of 78 bacteriophage particles per infected cell. The pH and thermal stability of bacteriophage VMY22 were also investigated. The maximum stability of the bacteriophage was observed to be at pH 8.0 and it was comparatively stable at p H 5.0–9.0. As VMY22 is a cold-active bacteriophage with low production temperature, its characterization and the relationship between MYB41-22 and Bacillus cereus bacteriophage deserve further study.
文摘Dioxygen activations constitute one of core issues in copper-dependent metalloenzymes. Upon O_(2) activation, copper-dependent metalloenzymes such as particulate methane monooxygenases(pM MOs), lytic polysaccharide monooxygenases(LPMOs) and binuclear copper enzymes PHM and DβM, are able to perform various challenging C–H bond activations. Meanwhile, various copper-oxygen core containing complexes have been synthetized to mimic the active species of metalloenzymes. Dioxygen activation by mononuclear copper active site may generate various copper-oxygen intermediates, including Cu(Ⅱ)-superoxo, Cu(Ⅱ)-hydroperoxo, Cu(Ⅱ)-oxyl as well as the Cu(Ⅲ)-hydroxide species. Intriguingly, all these species have been invoked as the potential active intermediates for C–H/O–H activations in either biological or synthetic systems. Due to the poor understanding on reactivities of copper-oxygen complex, the nature of active species in both biological and synthetic systems are highly controversial. In this account, we will compare the reactivities of various mononuclear copper-oxygen species between biological systems and the synthetic systems. The present study is expected to provide the consistent understanding on reactivities of various copper-oxygen active species in both biological and synthetic systems.
