A dATP conversion E. coli strain could be constructed when both pyk and adk1 gene were expressed successfully. pyk gene encodes pyruvate kinase (PK) could be expressed, when inserted it before adk1 gene which encodes ...A dATP conversion E. coli strain could be constructed when both pyk and adk1 gene were expressed successfully. pyk gene encodes pyruvate kinase (PK) could be expressed, when inserted it before adk1 gene which encodes adenylate kinase (AK) in plasmid pET-pyk-adk1 after transform into E. coli and the recombinant could be used to convert dATP from dAMP. Another plasmid pET-adk1-pyk, which inserted pyk gene behind of adk1, the recombinant E. coli transformed with this plasmid could not convert dAMP into dATP, pyk gene cannot be translated in this recombinant. The different translation levels of pyk with gene location switching caused mainly by the different secondary structures formed by the 5’-untranslation regions and the gene sequence of its5’-terminal. The dATP product E. coli strain could be constructed when cloned pyk gene at an optimum location.展开更多
We have developed a cell-free system that can trigger the nuclei purified from mouse liver and suspensioncultured carrot cells to undergo apoptosis as defined by the formation of apoptotic bodies and nucleosomal DNA f...We have developed a cell-free system that can trigger the nuclei purified from mouse liver and suspensioncultured carrot cells to undergo apoptosis as defined by the formation of apoptotic bodies and nucleosomal DNA fragments. The effects of different divalent cations and cycloheximide on DNA cleavage in this system were assessed.The fact that nuclei of plant cells can be induced to undergo apoptosis in a cell-free animal system suggests that animals and plants share a common signal transduction pathway triggering in the initiation stage of apoptosis.展开更多
The Saccharomyces cerevisiae polyphosphatase PPN1 (uniprot/Q04119) degrades inorganic polyphosphates both by cleaving Pi from the chain end and by fragmenting long-chain polymers into shorter ones. In this study, we h...The Saccharomyces cerevisiae polyphosphatase PPN1 (uniprot/Q04119) degrades inorganic polyphosphates both by cleaving Pi from the chain end and by fragmenting long-chain polymers into shorter ones. In this study, we have found a new activity of this protein: it releases phosphate from dATP. The dATP phosphohydrolase activity of pure PPN1 was ~7-fold lower compared to the exopolyphosphatase activity. This activity was strongly stimulated by Co<sup>2+</sup> ions, as well as by ammonium ions, and inhibited by heparin and pyrophosphate similar to the exopolyphosphatase activity of PPN1. The Km value for dATP was 0.88 ± 0.14 mM. The dATP phosphohydrolase activity in the cells of PPN1-overexpressing yeast strain was several-fold higher than that in the parent strain. The other exopolyphosphatase of S. cerevisiae, PPX1, did not split Pi from dATP.展开更多
The high risk of SARS-CoV-2 infection and reinfection and the occurrence of post-acute pulmonary sequelae have highlighted the importance of understanding the mechanism underlying lung repair after injury.To address t...The high risk of SARS-CoV-2 infection and reinfection and the occurrence of post-acute pulmonary sequelae have highlighted the importance of understanding the mechanism underlying lung repair after injury.To address this concern,comparative and systematic analyses of SARS-CoV-2 infection in COVID-19 patients and animals were conducted.In the lungs of nine patients who died of COVID-19 and one recovered from COVID-19 but died of unrelated disease in early 2020,damage-related transient progenitor(DATP)cells expressing CK8 marker proliferated significantly.These CK8^(+)DATP cells were derived from bronchial CK5^(+)basal cells.However,they showed different cell fate toward differentiation into type I alveolar cells in the deceased and convalescent patients,respectively.By using a self-limiting hamster infection model mimicking the dynamic process of lung injury remodeling in mild COVID-19 patients,the accumulation and regression of CK8t cell marker were found to be closely associated with the disease course.Finally,we examined the autopsied lungs of two patients who died of infection by the recent Omicron variant and found that they only exhibited mild pathological injury with no CK8^(+)cell proliferation.These results indicate a clear pulmonary cell remodeling route and suggest that CK8^(+)DATP cells play a primary role in mediating alveolar remodeling,highlighting their potential applications as diagnostic markers and therapeutic targets.展开更多
文摘A dATP conversion E. coli strain could be constructed when both pyk and adk1 gene were expressed successfully. pyk gene encodes pyruvate kinase (PK) could be expressed, when inserted it before adk1 gene which encodes adenylate kinase (AK) in plasmid pET-pyk-adk1 after transform into E. coli and the recombinant could be used to convert dATP from dAMP. Another plasmid pET-adk1-pyk, which inserted pyk gene behind of adk1, the recombinant E. coli transformed with this plasmid could not convert dAMP into dATP, pyk gene cannot be translated in this recombinant. The different translation levels of pyk with gene location switching caused mainly by the different secondary structures formed by the 5’-untranslation regions and the gene sequence of its5’-terminal. The dATP product E. coli strain could be constructed when cloned pyk gene at an optimum location.
文摘We have developed a cell-free system that can trigger the nuclei purified from mouse liver and suspensioncultured carrot cells to undergo apoptosis as defined by the formation of apoptotic bodies and nucleosomal DNA fragments. The effects of different divalent cations and cycloheximide on DNA cleavage in this system were assessed.The fact that nuclei of plant cells can be induced to undergo apoptosis in a cell-free animal system suggests that animals and plants share a common signal transduction pathway triggering in the initiation stage of apoptosis.
文摘The Saccharomyces cerevisiae polyphosphatase PPN1 (uniprot/Q04119) degrades inorganic polyphosphates both by cleaving Pi from the chain end and by fragmenting long-chain polymers into shorter ones. In this study, we have found a new activity of this protein: it releases phosphate from dATP. The dATP phosphohydrolase activity of pure PPN1 was ~7-fold lower compared to the exopolyphosphatase activity. This activity was strongly stimulated by Co<sup>2+</sup> ions, as well as by ammonium ions, and inhibited by heparin and pyrophosphate similar to the exopolyphosphatase activity of PPN1. The Km value for dATP was 0.88 ± 0.14 mM. The dATP phosphohydrolase activity in the cells of PPN1-overexpressing yeast strain was several-fold higher than that in the parent strain. The other exopolyphosphatase of S. cerevisiae, PPX1, did not split Pi from dATP.
基金supported by grants from the National Key R&D Programof China(2021YFC2301700,2020YFC0844700,2021YFF0702002)Hubei Natural Science Foundation for Distinguished Young Scholars(2021CFA050 and 2021CFA053).
文摘The high risk of SARS-CoV-2 infection and reinfection and the occurrence of post-acute pulmonary sequelae have highlighted the importance of understanding the mechanism underlying lung repair after injury.To address this concern,comparative and systematic analyses of SARS-CoV-2 infection in COVID-19 patients and animals were conducted.In the lungs of nine patients who died of COVID-19 and one recovered from COVID-19 but died of unrelated disease in early 2020,damage-related transient progenitor(DATP)cells expressing CK8 marker proliferated significantly.These CK8^(+)DATP cells were derived from bronchial CK5^(+)basal cells.However,they showed different cell fate toward differentiation into type I alveolar cells in the deceased and convalescent patients,respectively.By using a self-limiting hamster infection model mimicking the dynamic process of lung injury remodeling in mild COVID-19 patients,the accumulation and regression of CK8t cell marker were found to be closely associated with the disease course.Finally,we examined the autopsied lungs of two patients who died of infection by the recent Omicron variant and found that they only exhibited mild pathological injury with no CK8^(+)cell proliferation.These results indicate a clear pulmonary cell remodeling route and suggest that CK8^(+)DATP cells play a primary role in mediating alveolar remodeling,highlighting their potential applications as diagnostic markers and therapeutic targets.
