Fluorescence correlation spectroscopy （FCS） without objective image magnification （without using con-focal microscope） was applied to observe the variation in cell size of Escherichia coli （E. coli） induced by t...Fluorescence correlation spectroscopy （FCS） without objective image magnification （without using con-focal microscope） was applied to observe the variation in cell size of Escherichia coli （E. coli） induced by the anti-cancer agent MitomycinC （MMC）. In the system without image magnification followed in this study, the suspension of E. coli cells was stirred, and the difference in movement due to the different cell sizes induced by the compulsive solution flow was detected. The addition of 0.1-0.4 pg/L of MMC elongated the E. coli cell length from about 3.6 to 7.8μm. The flow cell （i.d. = about 1 mm） also produced a size-dependent correlation curve, The present system is not based on single molecular FCS but is inexpensive and effective at observing the variation in cell size induced by environmental changes.展开更多
8,2＇-Diprenylquercetin 3-methyl ether with significant anti-breast cancer activity is the main constituent of Tibetan medicine Sinopodophylli Fructus. In the present study, we developed and validated a rapid and sens...8,2＇-Diprenylquercetin 3-methyl ether with significant anti-breast cancer activity is the main constituent of Tibetan medicine Sinopodophylli Fructus. In the present study, we developed and validated a rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） method for the determination of 8,2＇-diprenylquercetin 3-methyl ether in rat plasma. 8-Prenylkaempferol was used as the internal standard. The separation was carried out using Waters ACQUITY UPLC BEH C18 column （2.1 mm×100 ram, 1.7 μm） with a mobile phase consisting of acetonitrile and 0.1% formic acid in water on a gradient program at a flow rate of 0.4 mL＇min-1 and temperature of 30 ℃. Triple quadrupole mass spectrometric detection in negative ion mode was used for multiple-reaction monitoring of the transitions at m/z 451.30→177.25 and m/z 353.25→298.15 for 8,2＇-diprenylquercetin 3-methyl ether and 8-prenylkaempferol, respectively. The calibration curves were linear within the concentration range 0.1-2000 ng/mL （r = 0.9954）. The recoveries were 103%-115%, and the results were consistent across low, middle and high concentration levels. The intra- and inter-day precisions were within 15%, and the bias was between --6%-15%. This method was simple, rapid and sensitive, which could be applied to the determination of 8,2＇-diprenylquercetin 3-methyl ether in plasma and pharmacokinetic study in rats. Pharmacokinetic test indicated that the peak plasma concentration occurred in 2 h after the female rats were intragastrically administered with 8,2＇-diprenylquercetin 3-methyl ether at the dose of 100 mg/kg, and the biological half-life was 6.79 h. The blood drug concentration maintained equal amount for 20 h, which was conducive to the in vivo effects of drugs.展开更多
文摘Fluorescence correlation spectroscopy （FCS） without objective image magnification （without using con-focal microscope） was applied to observe the variation in cell size of Escherichia coli （E. coli） induced by the anti-cancer agent MitomycinC （MMC）. In the system without image magnification followed in this study, the suspension of E. coli cells was stirred, and the difference in movement due to the different cell sizes induced by the compulsive solution flow was detected. The addition of 0.1-0.4 pg/L of MMC elongated the E. coli cell length from about 3.6 to 7.8μm. The flow cell （i.d. = about 1 mm） also produced a size-dependent correlation curve, The present system is not based on single molecular FCS but is inexpensive and effective at observing the variation in cell size induced by environmental changes.
基金National Natural Science Foundation of China(Grant No.81673590)National Key Technology R&D Program "New Drug Innovation" of China(Grant No.2013ZX09103002-006)
文摘8,2＇-Diprenylquercetin 3-methyl ether with significant anti-breast cancer activity is the main constituent of Tibetan medicine Sinopodophylli Fructus. In the present study, we developed and validated a rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） method for the determination of 8,2＇-diprenylquercetin 3-methyl ether in rat plasma. 8-Prenylkaempferol was used as the internal standard. The separation was carried out using Waters ACQUITY UPLC BEH C18 column （2.1 mm×100 ram, 1.7 μm） with a mobile phase consisting of acetonitrile and 0.1% formic acid in water on a gradient program at a flow rate of 0.4 mL＇min-1 and temperature of 30 ℃. Triple quadrupole mass spectrometric detection in negative ion mode was used for multiple-reaction monitoring of the transitions at m/z 451.30→177.25 and m/z 353.25→298.15 for 8,2＇-diprenylquercetin 3-methyl ether and 8-prenylkaempferol, respectively. The calibration curves were linear within the concentration range 0.1-2000 ng/mL （r = 0.9954）. The recoveries were 103%-115%, and the results were consistent across low, middle and high concentration levels. The intra- and inter-day precisions were within 15%, and the bias was between --6%-15%. This method was simple, rapid and sensitive, which could be applied to the determination of 8,2＇-diprenylquercetin 3-methyl ether in plasma and pharmacokinetic study in rats. Pharmacokinetic test indicated that the peak plasma concentration occurred in 2 h after the female rats were intragastrically administered with 8,2＇-diprenylquercetin 3-methyl ether at the dose of 100 mg/kg, and the biological half-life was 6.79 h. The blood drug concentration maintained equal amount for 20 h, which was conducive to the in vivo effects of drugs.
