Structural parameters of 22 halogen phenols were computed at four levels using Hartree-Fock and DFT methods. Based on the experimental data of the acute toxicity to Tetrahymena pyriformis （-lgEC_50）, three-parameter...Structural parameters of 22 halogen phenols were computed at four levels using Hartree-Fock and DFT methods. Based on the experimental data of the acute toxicity to Tetrahymena pyriformis （-lgEC_50）, three-parameter （energy of the lowest unoccupied molecular orbital （E_LUMO）, the molecular volume （V）, and the lowest negative charge （Q_min）） dependent equations were developed using structural parameters as theoretical descriptors. Especially, -lgEC_50dependent equation calculated at the B3LYP/6-31G^＊＊ level is more advantageous than the others in view of their correlation and predictive abilities. This dependent equation was validated by variance inflation factors （VIF） and t-test methods. Upon comparison, the predictive abilities of our work are all more advantageous than those calculated from the semi-empirical PM3 method.展开更多
The IGC 50 (50% inhibitory growth concentration) values of 27 nitrobenzenes were determined for the population growth endpoint of Tetrahymena pyriformis . The toxicity order of the observed compounds was found to be a...The IGC 50 (50% inhibitory growth concentration) values of 27 nitrobenzenes were determined for the population growth endpoint of Tetrahymena pyriformis . The toxicity order of the observed compounds was found to be as follows: dinitro compounds>mononitro compounds, dichloronitrobenzenes>monochloronitrobenzenes, meta substituted nitrobenzenes>ortho /para substituted nitrobenzenes(NT, NPh, NAnis) except for the dinitrobenzenes and nitroanilines(DNB, NAn). Quantitative structure activity relationships(QSARs) were developed with the logarithm of the reciprocal of IGC 50 [lg(IGC 50 ) -1 ] in mole liter as dependent variable and six molecular descriptors lg P , 1 X Ⅴ, I, 1K a, ∑σ - and E LUMO as independent variables. Via multiple regression analysis, one best equation was obtained: lg(IGC 50 ) -1 =3.029+0.860∑ σ -+0.341I n=27, r=0.924, r 2=0.854, s=0.265, f=70.44 , Pr> f =0.000 1 The equation was used to estimate IGC 50 for five analogues.展开更多
The molecular electronegativity interaction vector （MEIV） was used to describe the molecular structure of 30 selected esters. Two excellent QSTR models were built up by using multiple linear regression （MLR） and p...The molecular electronegativity interaction vector （MEIV） was used to describe the molecular structure of 30 selected esters. Two excellent QSTR models were built up by using multiple linear regression （MLR） and partial least-squares regression （PLS）. The correlation coefficients （R） of the two models were 0.945 and 0.941, respectively. The models were evaluated by performing the cross validation with the leave-one-out （LOO） procedure. The cross-verification correlation coefficients （RCV） of the two models were 0.921 and 0.919, respectively. The results showed that the models constructed in this work could provide estimation stability and favorable predictive ability.展开更多
The impact of diflubenzuron (DFB) on Tetrahymena pyriformis, a ciliated protiste was studied. The treatment with DFB at concentrations of 10 and 20 μg/mL could appreciably reduce the growth of the protiste. The surve...The impact of diflubenzuron (DFB) on Tetrahymena pyriformis, a ciliated protiste was studied. The treatment with DFB at concentrations of 10 and 20 μg/mL could appreciably reduce the growth of the protiste. The surveillance of protozoa′s respiratory metabolism with polarography technique showed a sensitive inhibition of its oxygen consumption, and at 20 μg/mL concentration the oxygen consumption was increased. For any malformation of morphology and perturbation in swimming trajectory, the neutral red coloration was done. This technique (neutral red) showed that there was a toxic effect of DFB on T. pyriformis, especially at the highest concentration; this toxicity was translated by rotatory swimming in same place and the increasing of coloration quantity in digestive vacuoles. Fig 5, Ref展开更多
Staphylococcus aureus is one of the main pathogenic agents responsible for nosocomial and community-acquired bacterial infections. The pathogenicity of this Gram-positive bacterium is ensured by its different adhesion...Staphylococcus aureus is one of the main pathogenic agents responsible for nosocomial and community-acquired bacterial infections. The pathogenicity of this Gram-positive bacterium is ensured by its different adhesion factors. Collagen and the extracellular glycoprotein adhesin are among the Staphylococcus most important virulence factors. It has been shown that most of the S. aureus strains carry the ica operon, responsible for biofilm production. However, the coexpression of the icaA and the icaD genes is necessary for complete biofilm synthesis. The aim of our study was to study a collection of 15 clinical strains of S. aureus from different sources for the presence of can and icaD genes coding intercellular adhesion proteins. We also intended to estimate the strains’ ability to form biofilms by the red Cong method and to test the adhesion ability of S. aureus to the ciliated protist Tetrahymena pyriformis, which we used as a novel cellular adhesion model. Finally, we checked the adhesion’s inhibition capacity of some plants extracts. The molecular detection of adhesion genes revealed that 80% of strains are cna positive, and 73% are icaD positive. Qualitative biofilm production of S. aureus revealed that 66.6% of strains were slime producers. The adhesion test revealed that 20% of strains are strongly adhering to T. pyriformis and that the Clematis cirrhosa extract has an anti-adhering effect of S. aureus to the ciliate T. pyriformis.展开更多
magnetotactic Tetrahymena pyriformis GL （T. pyriformis） cells were created by the internalization of iron oxide nano particles and became controllable with a time-varying external magnetic field. Thus, T. pyriformis...magnetotactic Tetrahymena pyriformis GL （T. pyriformis） cells were created by the internalization of iron oxide nano particles and became controllable with a time-varying external magnetic field. Thus, T. pyriformis can be utilized as a cellular robot to conduct micro-scale tasks such as transportation and manipulation. To complete these tasks, loading inorganic or organic materials onto the cell body is essential, but functionalization of the cell membrane is obstructed by their motile organelles, cilia. Dibucaine HC1, a local anesthetic, removes the cilia from the cell body, and the functional group would be absorbed more efficiently during cilia regeneration. In this paper, we characterize the recovery of artificial magnetotactic T. pyriformis after the deciliation process to optimize a cellular robot fabrication process. After sufficient time to recover, the motility rate and the average velocity of the deciliated cells were six and ten percent lower than that of non-deciliated cells, respectively. We showed that the motile cells after recovery can still be controlled using magnetotaxis, making T. pyrfformis a good candidate to be used as a celIular robot.展开更多
基金support by the Natural Science Foundation of University, Anhui Province (No. 2006KJ156B)
文摘Structural parameters of 22 halogen phenols were computed at four levels using Hartree-Fock and DFT methods. Based on the experimental data of the acute toxicity to Tetrahymena pyriformis （-lgEC_50）, three-parameter （energy of the lowest unoccupied molecular orbital （E_LUMO）, the molecular volume （V）, and the lowest negative charge （Q_min）） dependent equations were developed using structural parameters as theoretical descriptors. Especially, -lgEC_50dependent equation calculated at the B3LYP/6-31G^＊＊ level is more advantageous than the others in view of their correlation and predictive abilities. This dependent equation was validated by variance inflation factors （VIF） and t-test methods. Upon comparison, the predictive abilities of our work are all more advantageous than those calculated from the semi-empirical PM3 method.
基金Supported by the Educational Ministry Foundation of China(No. 0 10 6 3) .Tetrahymena pyriformis B was kindlysupplied by Dr.TiedkeMünster
文摘The IGC 50 (50% inhibitory growth concentration) values of 27 nitrobenzenes were determined for the population growth endpoint of Tetrahymena pyriformis . The toxicity order of the observed compounds was found to be as follows: dinitro compounds>mononitro compounds, dichloronitrobenzenes>monochloronitrobenzenes, meta substituted nitrobenzenes>ortho /para substituted nitrobenzenes(NT, NPh, NAnis) except for the dinitrobenzenes and nitroanilines(DNB, NAn). Quantitative structure activity relationships(QSARs) were developed with the logarithm of the reciprocal of IGC 50 [lg(IGC 50 ) -1 ] in mole liter as dependent variable and six molecular descriptors lg P , 1 X Ⅴ, I, 1K a, ∑σ - and E LUMO as independent variables. Via multiple regression analysis, one best equation was obtained: lg(IGC 50 ) -1 =3.029+0.860∑ σ -+0.341I n=27, r=0.924, r 2=0.854, s=0.265, f=70.44 , Pr> f =0.000 1 The equation was used to estimate IGC 50 for five analogues.
基金supported by the Youth Foundation of Education Bureau, Sichuan Province (09ZB036)Technology Bureau, Sichuan Province (2006j13-141)
文摘The molecular electronegativity interaction vector （MEIV） was used to describe the molecular structure of 30 selected esters. Two excellent QSTR models were built up by using multiple linear regression （MLR） and partial least-squares regression （PLS）. The correlation coefficients （R） of the two models were 0.945 and 0.941, respectively. The models were evaluated by performing the cross validation with the leave-one-out （LOO） procedure. The cross-verification correlation coefficients （RCV） of the two models were 0.921 and 0.919, respectively. The results showed that the models constructed in this work could provide estimation stability and favorable predictive ability.
文摘The impact of diflubenzuron (DFB) on Tetrahymena pyriformis, a ciliated protiste was studied. The treatment with DFB at concentrations of 10 and 20 μg/mL could appreciably reduce the growth of the protiste. The surveillance of protozoa′s respiratory metabolism with polarography technique showed a sensitive inhibition of its oxygen consumption, and at 20 μg/mL concentration the oxygen consumption was increased. For any malformation of morphology and perturbation in swimming trajectory, the neutral red coloration was done. This technique (neutral red) showed that there was a toxic effect of DFB on T. pyriformis, especially at the highest concentration; this toxicity was translated by rotatory swimming in same place and the increasing of coloration quantity in digestive vacuoles. Fig 5, Ref
文摘Staphylococcus aureus is one of the main pathogenic agents responsible for nosocomial and community-acquired bacterial infections. The pathogenicity of this Gram-positive bacterium is ensured by its different adhesion factors. Collagen and the extracellular glycoprotein adhesin are among the Staphylococcus most important virulence factors. It has been shown that most of the S. aureus strains carry the ica operon, responsible for biofilm production. However, the coexpression of the icaA and the icaD genes is necessary for complete biofilm synthesis. The aim of our study was to study a collection of 15 clinical strains of S. aureus from different sources for the presence of can and icaD genes coding intercellular adhesion proteins. We also intended to estimate the strains’ ability to form biofilms by the red Cong method and to test the adhesion ability of S. aureus to the ciliated protist Tetrahymena pyriformis, which we used as a novel cellular adhesion model. Finally, we checked the adhesion’s inhibition capacity of some plants extracts. The molecular detection of adhesion genes revealed that 80% of strains are cna positive, and 73% are icaD positive. Qualitative biofilm production of S. aureus revealed that 66.6% of strains were slime producers. The adhesion test revealed that 20% of strains are strongly adhering to T. pyriformis and that the Clematis cirrhosa extract has an anti-adhering effect of S. aureus to the ciliate T. pyriformis.
基金The authors are grateful for the financial support of the National Science Foundation （NSF CAREER CMMI-0745019 and CMMI-1000255）. This research was partially supported by Basic Science Research Program through the National Research Foundation of Korea （NRF） （2011-0019122）. We acknowledge the help of Lhszl6 KShidai and A. Agung Julius for their valuable discussions.
文摘magnetotactic Tetrahymena pyriformis GL （T. pyriformis） cells were created by the internalization of iron oxide nano particles and became controllable with a time-varying external magnetic field. Thus, T. pyriformis can be utilized as a cellular robot to conduct micro-scale tasks such as transportation and manipulation. To complete these tasks, loading inorganic or organic materials onto the cell body is essential, but functionalization of the cell membrane is obstructed by their motile organelles, cilia. Dibucaine HC1, a local anesthetic, removes the cilia from the cell body, and the functional group would be absorbed more efficiently during cilia regeneration. In this paper, we characterize the recovery of artificial magnetotactic T. pyriformis after the deciliation process to optimize a cellular robot fabrication process. After sufficient time to recover, the motility rate and the average velocity of the deciliated cells were six and ten percent lower than that of non-deciliated cells, respectively. We showed that the motile cells after recovery can still be controlled using magnetotaxis, making T. pyrfformis a good candidate to be used as a celIular robot.
基金Supported by the Strategic Eleventh -five -year Science and Technology Supporting Grant (No. 2006BAK10B09) from the Ministry of National Science and Technology of China
