Over the past seven decades, the grain yield of maize(Zea mays L.) has increased continuously in China, mostly due to hybridization innovations, particularly recent genetic improvements in photosynthesis. In order to ...Over the past seven decades, the grain yield of maize(Zea mays L.) has increased continuously in China, mostly due to hybridization innovations, particularly recent genetic improvements in photosynthesis. In order to reveal photosynthetic characters of elite inbred lines in different ears, a field experiment was conducted at the North China Plain of Shandong Province in China. Six parental lines of maize introduced in three eras(the 1960 s, 1980 s, and 2000 s) were investigated diurnal variation of gas exchange, chlorophyll fluorescence, and photosynthetic response characteristic at the grain filling stage. Compared to earlier parental lines, the 2000 s parental lines always had higher net photosynthetic rate(Pn) throughout the day, especially at noon, and a mid-day depression in Pn did not occur in all hybrids parental lines. Moreover, the stomatal conductance(Gs) and water use efficiency(WUE) of the 2000 s’ lines showed higher value than those of the 1960 s’ and 1980 s’ lines. The inbred lines differences in photosynthetic parameters were partly owing to their different quantum carboxylation efficiencies and light synthase activities. Simultaneously, the 2000 s parental lines exhibited lower light and CO2 compensation points, and their higher apparent quantum yield, and carboxylation efficiency. These suggested that the modern parental lines required lower light intensity and less CO2 to maintain a relatively high photosynthetic capacity, substantially increasing leaf physical quality and stress resistance. It provided crucial information of high photo-efficiency and stress-resistance breeding in maize.展开更多
This paper reports the synthesis and general properties of the new reagent CPFP. Its dissociation constants have been determined. The characterization in determinating total RE with CPAP reagent has been investigated ...This paper reports the synthesis and general properties of the new reagent CPFP. Its dissociation constants have been determined. The characterization in determinating total RE with CPAP reagent has been investigated in detail. Analytic data for synthetic sample are satisfactory.展开更多
The bacterial ATP-competitive GyrB/ParE subunits of type II topoisomerase are important anti-bacterial targets to treat super drug-resistant bacterial infections.Herein we discovered novel pyrrolamide-type GyrB/ParE i...The bacterial ATP-competitive GyrB/ParE subunits of type II topoisomerase are important anti-bacterial targets to treat super drug-resistant bacterial infections.Herein we discovered novel pyrrolamide-type GyrB/ParE inhibitors based on the structural modifications of the candidate AzD5099 that was withdrawn from the clinical trials due to safety liabilities such as mitochondrial toxicity.The hydroxyisopropyl pyridazine compound 28 had a significant inhibitory effect on Gyrase(GyrB,IC_(50)=49 nmol/L)and a modest inhibitory effect on TopoⅣ(ParE,IC_(50)=1.513μmol/L)of Staphylococcus aureus.It also had significant antibacterial activities on susceptible and resistant Gram-positive bacteria with a minimum inhibitory concentration(MIC)of less than 0.03μg/mL,which showed a time-dependent bactericidal effect and low frequencies of spontaneous resistance against S.aureus.Compound 28 had better protective effects than the positive control drugs such as DS-2969(5)and AZD5099(6)in mouse models of sepsis induced by methicillin-resistant Staphylococcus aureus(MRSA)infection.It also showed better bactericidal activities than clinically used vancomycin in the mouse thigh MRSA infection models.Moreover,compound 28 has much lower mitochondrial toxicity than AZD5099(6)as well as excellent therapeutic indexes and pharmacokinetic properties.At present,compound 28 has been evaluated as a pre-clinical drug candidate for the treatment of drug-resistant Gram-positive bacterial infection.On the other hand,compound 28 also has good inhibitory activities against stubborn Gram-negative bacteria such as Escherichia coli(MIC=1μg/mL),which is comparable with the most potent pyrrolamide-type GyrB/ParE inhibitors reported recently.In addition,the structure-activity relationships of the compounds were also studied.展开更多
基金funded by the National Key Research and Development Program of China (2016YFD0300103)the earmarked fund for China Agriculture Research System (CARS-02-12)
文摘Over the past seven decades, the grain yield of maize(Zea mays L.) has increased continuously in China, mostly due to hybridization innovations, particularly recent genetic improvements in photosynthesis. In order to reveal photosynthetic characters of elite inbred lines in different ears, a field experiment was conducted at the North China Plain of Shandong Province in China. Six parental lines of maize introduced in three eras(the 1960 s, 1980 s, and 2000 s) were investigated diurnal variation of gas exchange, chlorophyll fluorescence, and photosynthetic response characteristic at the grain filling stage. Compared to earlier parental lines, the 2000 s parental lines always had higher net photosynthetic rate(Pn) throughout the day, especially at noon, and a mid-day depression in Pn did not occur in all hybrids parental lines. Moreover, the stomatal conductance(Gs) and water use efficiency(WUE) of the 2000 s’ lines showed higher value than those of the 1960 s’ and 1980 s’ lines. The inbred lines differences in photosynthetic parameters were partly owing to their different quantum carboxylation efficiencies and light synthase activities. Simultaneously, the 2000 s parental lines exhibited lower light and CO2 compensation points, and their higher apparent quantum yield, and carboxylation efficiency. These suggested that the modern parental lines required lower light intensity and less CO2 to maintain a relatively high photosynthetic capacity, substantially increasing leaf physical quality and stress resistance. It provided crucial information of high photo-efficiency and stress-resistance breeding in maize.
文摘This paper reports the synthesis and general properties of the new reagent CPFP. Its dissociation constants have been determined. The characterization in determinating total RE with CPAP reagent has been investigated in detail. Analytic data for synthetic sample are satisfactory.
基金the financial support from the CAMS Innovation Fund for Medical Sciences(2021-I2M-1-030,China)the Science and Technology Commission Foundation of Beijing(Z221100007922045,China).
文摘The bacterial ATP-competitive GyrB/ParE subunits of type II topoisomerase are important anti-bacterial targets to treat super drug-resistant bacterial infections.Herein we discovered novel pyrrolamide-type GyrB/ParE inhibitors based on the structural modifications of the candidate AzD5099 that was withdrawn from the clinical trials due to safety liabilities such as mitochondrial toxicity.The hydroxyisopropyl pyridazine compound 28 had a significant inhibitory effect on Gyrase(GyrB,IC_(50)=49 nmol/L)and a modest inhibitory effect on TopoⅣ(ParE,IC_(50)=1.513μmol/L)of Staphylococcus aureus.It also had significant antibacterial activities on susceptible and resistant Gram-positive bacteria with a minimum inhibitory concentration(MIC)of less than 0.03μg/mL,which showed a time-dependent bactericidal effect and low frequencies of spontaneous resistance against S.aureus.Compound 28 had better protective effects than the positive control drugs such as DS-2969(5)and AZD5099(6)in mouse models of sepsis induced by methicillin-resistant Staphylococcus aureus(MRSA)infection.It also showed better bactericidal activities than clinically used vancomycin in the mouse thigh MRSA infection models.Moreover,compound 28 has much lower mitochondrial toxicity than AZD5099(6)as well as excellent therapeutic indexes and pharmacokinetic properties.At present,compound 28 has been evaluated as a pre-clinical drug candidate for the treatment of drug-resistant Gram-positive bacterial infection.On the other hand,compound 28 also has good inhibitory activities against stubborn Gram-negative bacteria such as Escherichia coli(MIC=1μg/mL),which is comparable with the most potent pyrrolamide-type GyrB/ParE inhibitors reported recently.In addition,the structure-activity relationships of the compounds were also studied.
