Legionella pneumophila is a Gram-negative bacterium ubiquitously present in freshwater environments and causes a serious type of pneumonia called Legionnaires’disease.During infections,L.pneumophila releases over 300...Legionella pneumophila is a Gram-negative bacterium ubiquitously present in freshwater environments and causes a serious type of pneumonia called Legionnaires’disease.During infections,L.pneumophila releases over 300 effector proteins into host cells through an Icm/Dot type IV secretion system to manipulate the host defense system for survival within the host.Notably,certain effector proteins mediate posttranslational modifications(PTMs),serving as useful approaches exploited by L.pneumophila to modify host proteins.Some effectors catalyze the addition of host protein PTMs,while others mediate the removal of PTMs from host proteins.In this review,we summarize L.pneumophila effector-mediated PTMs of host proteins,including phosphorylation,ubiquitination,glycosylation,AMPylation,phosphocholination,methylation,and ADP-ribosylation,as well as dephosphorylation,deubiquitination,deAMPylation,deADP-ribosylation,dephosphocholination,and delipidation.We describe their molecular mechanisms and biological functions in the regulation of bacterial growth and Legionella-containing vacuole biosynthesis and in the disruption of host immune and defense machinery.展开更多
The responses of cement mortar specimens of different dimensions under compression and tension were calculated based on the discrete element method with the modified-rigid-body-spring concrete model,in which the mecha...The responses of cement mortar specimens of different dimensions under compression and tension were calculated based on the discrete element method with the modified-rigid-body-spring concrete model,in which the mechanical parameters derived from macro-scale material tests were applied directly to the mortar elements.By comparing the calculated results with those predicted by the Carpinteri andWeibull size effects laws,a series of formulas to convert the macro-scale mechanical parameters of mortar and interface to those at the meso-scale were proposed through a fitting analysis.Based on the proposed formulas,numerical simulation of axial compressive and tensile failure processes of concrete and cement mortar materials,respectively were conducted.The calculated results were a good match with the test results.展开更多
基金funded by the National Natural Science Foundation of China(32170185,22011530161,31801166,and 91854101)the Natural Science Foundation of Chongqing,China(cstc2021jcyj-msxmX0030 and CSTB2022NSCQ-MSX0463)+2 种基金the Venture Innovation Support Program for Chongqing Overseas Returnees(cx2022066)the Fundamental Research Funds for the Central Universities(2022CDJYGRH-002)the National Training Program of Innovation and Entrepreneurship for Undergraduates(202210611088).
文摘Legionella pneumophila is a Gram-negative bacterium ubiquitously present in freshwater environments and causes a serious type of pneumonia called Legionnaires’disease.During infections,L.pneumophila releases over 300 effector proteins into host cells through an Icm/Dot type IV secretion system to manipulate the host defense system for survival within the host.Notably,certain effector proteins mediate posttranslational modifications(PTMs),serving as useful approaches exploited by L.pneumophila to modify host proteins.Some effectors catalyze the addition of host protein PTMs,while others mediate the removal of PTMs from host proteins.In this review,we summarize L.pneumophila effector-mediated PTMs of host proteins,including phosphorylation,ubiquitination,glycosylation,AMPylation,phosphocholination,methylation,and ADP-ribosylation,as well as dephosphorylation,deubiquitination,deAMPylation,deADP-ribosylation,dephosphocholination,and delipidation.We describe their molecular mechanisms and biological functions in the regulation of bacterial growth and Legionella-containing vacuole biosynthesis and in the disruption of host immune and defense machinery.
基金The financial support from the National Natural Science Foundation of China(Grant No.50978191)is sincerely acknowledged by the authors.
文摘The responses of cement mortar specimens of different dimensions under compression and tension were calculated based on the discrete element method with the modified-rigid-body-spring concrete model,in which the mechanical parameters derived from macro-scale material tests were applied directly to the mortar elements.By comparing the calculated results with those predicted by the Carpinteri andWeibull size effects laws,a series of formulas to convert the macro-scale mechanical parameters of mortar and interface to those at the meso-scale were proposed through a fitting analysis.Based on the proposed formulas,numerical simulation of axial compressive and tensile failure processes of concrete and cement mortar materials,respectively were conducted.The calculated results were a good match with the test results.