Mitogen-activated protein kinase （MAPK） cascades play important roles in regulating plant innate immune responses. In a genetic screen to search for mutants with constitutive defense responses, we identified multipl...Mitogen-activated protein kinase （MAPK） cascades play important roles in regulating plant innate immune responses. In a genetic screen to search for mutants with constitutive defense responses, we identified multiple alleles of mpk4 and mekkl that exhibit cell death and constitutive defense responses. Bimolecular fluorescence complemen- tation （BiFC） analysis showed that both MPK4 and MEKK1 interact with MKK1 and MKK2, two closely related MAPK kinases, mkkl and mkk2 single mutant plants do not have obvious mutant phenotypes. To test whether MKK1 and MKK2 function redundantly, mkkl mkk2 double mutants were generated. The mkkl mkk2 double mutant plants die at seedling stage and the seedling-lethality phenotype is temperature-dependent. Similar to the mpk4 and mekkl mutants, the mkkl mkk2 double mutant seedlings accumulate high levels of H202, display spontaneous cell death, constitutively express Pathogenesis Related （PR） genes and exhibit pathogen resistance. In addition, activation of MPK4 by fig22 is impaired in the mkkl mkk2 double mutants, suggesting that MKK1 and MKK2 function together with MPK4 and MEKK1 in a MAP kinase cascade to negatively regulate innate immune responses in plants.展开更多
Dear Editor,Ferroptosis has emerged as a new programmed cell death modality highly relevant to disease.1 Ferroptosis was initially discovered as an iron-dependent non-apoptotic cell death induced by a serial of ferrop...Dear Editor,Ferroptosis has emerged as a new programmed cell death modality highly relevant to disease.1 Ferroptosis was initially discovered as an iron-dependent non-apoptotic cell death induced by a serial of ferroptosis-inducing agents(FIN),such as erastin and RSL3.Erastin activates ferroptosis by inhibiting the activity of system Xc−,a cystine-glutamate antiporter,resulting in the depletion of cellular cysteine and glutathione(GSH),thus breaking cellular redox homeostasis.Inactivation of glutathione peroxidase 4(GPX4),an enzyme required to remove the toxic lipid hydroperoxides can induce ferroptosis without the depletion of cellular cysteine and GSH.展开更多
Dear Editor,Macroautophagy(referred to as autophagy herein)is an evolutionarily con served,lysosomal degradatio n process by which cells rid themselves of aggregated proteins and damaged organelles(He and Klionsky,200...Dear Editor,Macroautophagy(referred to as autophagy herein)is an evolutionarily con served,lysosomal degradatio n process by which cells rid themselves of aggregated proteins and damaged organelles(He and Klionsky,2009).This process involves a finely orchestrated molecular pathway comprising a plethora of ATG proteins essential for autophagosome formation.The mammalian Unc-51-like kinase(ULK)complex plays an essential role to initiate canonical autophagy pathway by relaying upstream nutrient and stress signals to downstream autophagy machinery(Mizushima,2010;Wong et al.,2013).展开更多
“Happy Chinese”or kuaile hanyu is an educational melodrama produced by the Chinese TV channel CCTV in 2009.Aiming to improve foreign learners’Chinese language skills,the plot revolves around Susan,an American,stayi...“Happy Chinese”or kuaile hanyu is an educational melodrama produced by the Chinese TV channel CCTV in 2009.Aiming to improve foreign learners’Chinese language skills,the plot revolves around Susan,an American,staying with her former Chinese classmate’s family.“Happy Chinese”proposes both language and cultural learning.In this paper,the authors are examining the first seven episodes marking Susan’s arrival in China for the Spring Festival.Basing the study on a postmodern and critical approach to the“intercultural,”as well as on a critical view towards Orientalism and Occidentalism,the authors are interested in how the programme constructs the arrival of the American and the way she is perceived and represented by the“locals.”The authors are also looking into what the Chinese family teaches Susan about being Chinese and,at the same time,the tensions that a certain tendency to“keep up appearances”and appear“real Chinese”before her trigger in the family,across generation and gender.The research tools used to analyze the data are derived from discursive pragmatics.展开更多
文摘Mitogen-activated protein kinase （MAPK） cascades play important roles in regulating plant innate immune responses. In a genetic screen to search for mutants with constitutive defense responses, we identified multiple alleles of mpk4 and mekkl that exhibit cell death and constitutive defense responses. Bimolecular fluorescence complemen- tation （BiFC） analysis showed that both MPK4 and MEKK1 interact with MKK1 and MKK2, two closely related MAPK kinases, mkkl and mkk2 single mutant plants do not have obvious mutant phenotypes. To test whether MKK1 and MKK2 function redundantly, mkkl mkk2 double mutants were generated. The mkkl mkk2 double mutant plants die at seedling stage and the seedling-lethality phenotype is temperature-dependent. Similar to the mpk4 and mekkl mutants, the mkkl mkk2 double mutant seedlings accumulate high levels of H202, display spontaneous cell death, constitutively express Pathogenesis Related （PR） genes and exhibit pathogen resistance. In addition, activation of MPK4 by fig22 is impaired in the mkkl mkk2 double mutants, suggesting that MKK1 and MKK2 function together with MPK4 and MEKK1 in a MAP kinase cascade to negatively regulate innate immune responses in plants.
基金supported by National Natural Science Foundation of China 31871388(to M.G.)Natural Science Foundation of Heilongjiang Province of China JJ2020YX0519(to MG).
文摘Dear Editor,Ferroptosis has emerged as a new programmed cell death modality highly relevant to disease.1 Ferroptosis was initially discovered as an iron-dependent non-apoptotic cell death induced by a serial of ferroptosis-inducing agents(FIN),such as erastin and RSL3.Erastin activates ferroptosis by inhibiting the activity of system Xc−,a cystine-glutamate antiporter,resulting in the depletion of cellular cysteine and glutathione(GSH),thus breaking cellular redox homeostasis.Inactivation of glutathione peroxidase 4(GPX4),an enzyme required to remove the toxic lipid hydroperoxides can induce ferroptosis without the depletion of cellular cysteine and GSH.
文摘Dear Editor,Macroautophagy(referred to as autophagy herein)is an evolutionarily con served,lysosomal degradatio n process by which cells rid themselves of aggregated proteins and damaged organelles(He and Klionsky,2009).This process involves a finely orchestrated molecular pathway comprising a plethora of ATG proteins essential for autophagosome formation.The mammalian Unc-51-like kinase(ULK)complex plays an essential role to initiate canonical autophagy pathway by relaying upstream nutrient and stress signals to downstream autophagy machinery(Mizushima,2010;Wong et al.,2013).
文摘“Happy Chinese”or kuaile hanyu is an educational melodrama produced by the Chinese TV channel CCTV in 2009.Aiming to improve foreign learners’Chinese language skills,the plot revolves around Susan,an American,staying with her former Chinese classmate’s family.“Happy Chinese”proposes both language and cultural learning.In this paper,the authors are examining the first seven episodes marking Susan’s arrival in China for the Spring Festival.Basing the study on a postmodern and critical approach to the“intercultural,”as well as on a critical view towards Orientalism and Occidentalism,the authors are interested in how the programme constructs the arrival of the American and the way she is perceived and represented by the“locals.”The authors are also looking into what the Chinese family teaches Susan about being Chinese and,at the same time,the tensions that a certain tendency to“keep up appearances”and appear“real Chinese”before her trigger in the family,across generation and gender.The research tools used to analyze the data are derived from discursive pragmatics.
