Microcalorimetric Study of the Action of Yb^3＋ ion on the Growth of Staphylococcus aureus

A microcalorimetric method was used to evaluate the action of Yb^3 ions onthe growth metabolism of Staphylococcus aureus.The power-time curves of the growth metabolism of Staphylo.coccus aureus and the action of Yb^3 ions were obtained by us-ing stopped-flow method at 37 ℃. For evaluation of the action,the growth rate constants ( k1 and k2) for the log phase 1, log phase 2, and the total heat effect (Qtotal) for Staphylococcus aureus were determined. The results show that Yb^3 ions at low concentrations have the stimnlatory effect on Staphylococcus au-reus and that Yb^3 ions at higher concentration could inhibit its growth.     

Microcalorimetric Studies on Influence of Sm^3＋, Dy^3＋ on Growth and Sporulation of Bacillus thuringiensis

By using an LKB-2277 Bioactivity Monitor and cycle-flow method, the thermogenic curves of aerobic growth for Bacillus thuringiensis cry Ⅱ strain at 28 ℃ have been obtained. The metabolic thermogenic curves of Bt cry Ⅱ contain two distinct parts: the first part reflects the changes of bacterial growth phase and the second part corresponds to sporulation phase. From these thermogenic curves in the absence or presence of Sm^3 , Dy^3 ions, the thermokinetic parameters such as the growth rate constants k. the interval time τ1, the maximum power PMAX1 and heat-output QLOG for log phase, the maximum power PMAX2 and heat-output QSTAT for stationary phase, the heat-output QSPOR for sporulation phase and total heat effects QT were calculated. Sm^3 and Dy^3 ions have promoting action on the growth of Bt cryⅡ in their lower concentration range, on the other hand, they have inhibitory action on the sporulation of Bt in their higher concentration range, It has also been found that the effects of Sm^3 and Dy^3 ions on Bt during the sporulation phase were far greater than those during the bacterial growth phase. It was concluded that the application of Bt for controlling insecticide could not be affected by the presence of the rare-earth elements in the environmental ecosystem.     

Microcalorimetric Study of the Biological Effects of Zn^＋ on Bacillus thuringiensis Growth

A microcalorimetric technique was used to investigate the influence of Zn^2 on the growth metabolism of Bacillus thuringiensis .LKB-2277 Bioactivity Monitor was employed to obtain the power-time curves,from which the maximum peak-heat output power(Pmax) in the log phase,the growth rate constants(k), the inhibitory ratios(I) ,the generational time(tG) and the total heat effect (Qtotal) in 23 h for the growth metabolism of Bacillus thuringiensis at 28℃ can be evaluated,The results indicate that the concentration of Zn^2 affects its growth obviously,Low concentration (0-50μg/mL) of Zn^2 promotes the growth of Bacillus thuringiensis while high concentration (50-500μg/mL) of Zn^2 inhibits its growth .When the concentration reached up to 600μg/mL,it can not grow at all.     

Thermodynamic and Kinetic Studies on the Sill ＋ XH3 （X=N, P） Reactions

Based on the quantum chemical study of the silylidyne insertion reaction with NH3 or PH3, the general statistical thermodynamics and Eyring transition state theory with Wigner correction are used to compute the changes of thermodynamic functions, equilibrium constants, A factors and rate constants of the two reactions in the temperature range 200-2000K. The results show that both of these reactions are thermodynamically dominant at low temperatures and kinetically favored at higher temperatures. The comparison between these two reactions shows that the Sill reaction with NH3 is more exothermic than Sill with PH3, while the rate constant of Sill reaction with NH3 is lower than that of Sill with PH3 at the same temperature.     

Mechanisms and Kinetics of Reactions of the O（^1D,^3P） ＋ CF3Cl System

In the stratosphere,CF3Cl(CFC13)can either photodecompose or react directly with atomic oxygen to generate ozone-depleting agents such as Cl and ClO in the gas phase[1—3].Since the1970s,attention has been focused on the effects of these compounds on the …     

Preparation of the Solid Electrolytes Li4＋xAlxSi1—xO4—yAl2O3 by the Sol—Gel Method and Study of Their Ionic Conductivity

ＩｎｔｒｏｄｕｃｔｉｏｎＬｉｔｈｉｕｍｉｏｎｃｏｎｄｕｃｔｏｒｓａｒｅｐｒｏｍｉｓｉｎｇｍａｔｅｒｉａｌｓｆｏｒｍａｎｙｋｉｎｄｓｏｆｅｌｅｃｔｒｏｃｈｅｍｉｃａｌａｐｐｌｉｃａｔｉｏｎ ,ｓｕｃｈａｓｅｌｅｃ ｔｒｏｌｙｔｅｓｆｏｒｈｉｇｈ ｅｎｅｒｇｙｄｅｎｓｉｔｙｂａｔｔｅｒｉｅｓ .1Ｔｈｅｐｒｏｐｅｒｔｉｅｓｏｆｈｉｇｈｉｏｎｉｃｃｏｎｄｕｃｔｉｖｉｔｙ ,ｈｉｇｈｄｅｃｏｍｐｏｓｉｔｉｏｎｐｏｔｅｎｔｉａｌ,ｓｔａｂｉｌｉｔｙａｎｄｃｏｍｐａｔｉｂｉｌｉｔｙａｇａｉｎｓｔｅｌｅｃｔｒｏｄｅｓｓ…     

Thermal Behavior and Decomposition Kinetics of the Complexes of CuX2 （X=NO3, Br, CI and CIO4） with 3,3＇-Dimethyl-1 -（1 H-1,2,4-triazol-1-yl）-2-butanone

The thermal behaviors of the complexes of Cu(DMTZB)4X2 (DMTZB=3,3‘-dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone, X=NO3 or ClO4) and Cu(DMTZB)2 X2 (X=Br or Cl) in a nitrogen atmosphere were studied under the non-isothermal conditions by simultaneous TG-DTG-DSC, EDS and elemental analysis techniques. The resuits showed that their decomposition proceeded in three different ways mainly depending on the anions in the molecules. The heat effect associated with the decomposition step of DMTZB molecules was also different. The decomposition mechanisms and the kinetic parameters of DMTZB were determined and calculated by jointly using four methods, which showed that its pyrolysis was controlled by D3 mechanism but with different activation energies and pre-exponential factors for different complexes.     

Microcalorimetric Studies on Gene Promoter Function of Cloned DNA Fragements from Halobacterium halobium J7 Plasmid pHH205 in Escherichia coli TG1

Halobacterium halobium is a typical kind of extremely halophilic bacterium. Combined with the antibiotic resistance assay, the microcalorimetric method was used to study the promoter function of the cloned DNA fragments from Halobacterium halobium J7 plasmid pHH205 in Escherichia coli TG1. The promoter probe vector, plasmid pKK232-8, was used to form the recombinants. The DNA fragment, which is the promoter for the chloramphenicol acetyl transferase （CAT） gene in plasmid pKK232-8, is about 800 bp, and the chloramphenicol resistance level presented by IC50 is about 200 μg·mL^-1, which suggests a high promoter activity. The conclusions show that there probably exist double-function or trinary-function gene promoters in Halobacterium halobium, and Archaea may contain rich genetic resources.     

Microcalorimetric Study of the Biological Effects of Zn~(2+) on Bacillus thuringiensis Growth

ＩｎｔｒｏｄｕｃｔｉｏｎＣａｌｏｒｉｍｅｔｒｙｈａｓｂｅｅｎｕｓｅｄｉｎｍｏｎｉｔｏｒｉｎｇｃｅｌｌｕｌａｒｍｅｔａｂｏｌｉｓｍｂｙｍｅａｎｓｏｆｈｅａｔｍｅａｓｕｒｅｍｅｎｔｓ ,ｅｓｐｅｃｉａｌｌｙｉｎｓｔｕｄｙｉｎｇｍｅｔａｂｏｌｉｓｍｉｎｃｅｌｌｓａｎｄｗｈｏｌｅｏｒｇａｎｉｓｍ .1,2 Ｍｉ ｃｒｏｃａｌｏｒｉｍｅｔｒｙｉｓａｌｓｏｕｓｅｄｉｎｍｅａｓｕｒｉｎｇｔｈｅｅｆｆｅｃｔｓｏｆｖａｒ ｉｏｕｓｓｕｂｓｔａｎｃｅｓａｎｄｃｕｌｔｕｒｅｃｏｎｄｉｔｉｏｎｓｏｎｍｅｔａｂｏｌｉｓｍ .Ｍｉｌｅ…     

Na~+/Ca~(2+) Exchange-mediated La~(3+) Entry in Human Lymphocytes

With extensive applications the rare earth elements to agriculture, medicine and animal husbandry, whether rare earth ions can cross cell membranes and participate in the metabolism of animals and plants is not clear until now. Otherwise, rare earth ions have different interaction fashions to different kinds of cells, therefore, in this study we determined whether La3+ enter human peripheral blood lymphocytes via Na+/Ca2+ exchanger (measured with fura-2).Relative sensitivity of fura-2 to Ca2+…     

硒的热化学研究：IV.微量热法研究Na2SeO3对微生物生长代谢的抑制

用微量热法研究了对大肠杆菌、产气杆菌、枯草杆菌、黑根霉菌４种菌作用的产热曲线，计算了微生物的生长速率常数ｋ，比较了Ｎａ２ＳｅＯ３对４种微生物作用的半抑制浓度ＩＣ５０，发现Ｎａ２ＳｅＯ３浓度低于１０ｍｇ／Ｌ时，对微生物生长有促进作用，高于此浓度时有抑制作用，对不同微生物生长代谢的抑制情况不同，反映了微生物之间的差异和硒对细胞作用热动力学特征的不同。     

微量热法研究硒代吗啉衍生物的抑菌作用

大肠杆菌;生长代谢;微量热法研究硒代吗啉衍生物的抑菌作用     

Microcalorimetric investigation of the effect of La3+ on mitochondria isolated from avian chicken liver tissue cells

A microcalorimetric technique was used to evaluate the influence of La³⁺ on mitochondria isolated from the liver tissue of Avian chicken. By means of LKB-2277 bioactivity monitor, ampoule method at 37°C, we obtained the thermogenic curves of the metabolism of mitochondria. After isolation from the chicken liver tissue, mitochondria still have metabolic activity and can live for a long time depending on the stored nutrients. In order to analyze the results, the maximum power (P _m) and the decline rate constants (k _d) were obtained. The addition of La³⁺ results in an increase of the maximum heat production and decline rate constants. Furthermore, values of P _m and k _d are linked to the concentration of La³⁺. According to the thermogenic curves under different conditions, it is clear that metabolic mechanism of mitochondria has been changed with the addition of La³⁺. This revised version was published online in August 2006 with corrections to the Cover Date.