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Rare-earth perchlorate complex coordinated with glycine [Nd2(Gly)6(H2O)4](ClO4)6·5H2O was synthesized and its structure was characterized by using thermogravimetric analysis (TG), differential thermal analysis (DTA), chemical analysis and elementary analysis. Its purity was 99.90%. Heat capacity measurement was carried out with a high-precision fully-automatic adiabatic calorimeter over the temperature range from 78 to 369 K. A solid-solid phase transformation peak was observed at 256.97 K, with the enthalpy and entropy of the phase transformation process are 4.438 kJ mol−1 and 17.270 J K−1 mol−1, respectively. There is a big dehydrated peak appears at 330 K, its decomposition temperature, decomposition enthalpy and entropy are 320.606 K, 41.364 kJ mol−1 and 129.018 J K−1 mol−1, respectively. The polynomial equations of heat capacity of this compound in different temperature ranges have been fitted. The standard enthalpy of formation was determined to be −8023.002 kJ mol−1 with isoperibol reaction calorimeter at 298.15 K. [ABSTRACT FROM AUTHOR]

A microcalorimetric technique based on the bacterial heat output was applied to evaluate the influence of plasmid copy number and various promoters on the green fluorescent protein expression inBacillus thuringiensis. The thermogenic curves of the aerobic metabolism ofB. thuringiensisstrains were determined by using an LKB-2277 bioactivity monitor at 28°C. The analysis of the thermogenic curves indicated for the first time that the more plasmid copy number per cell the more protein synthetization. PromoterBtI-BtIIhad a stronger impact on the gene expression than promoter3Ainvestigated by the method of microcalorimetry. [ABSTRACT FROM AUTHOR]

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 (Pm) and the decline rate constants (kd) were obtained. The addition of La3+ results in an increase of the maximum heat production and decline rate constants. Furthermore, values of Pm and kd 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+. [ABSTRACT FROM AUTHOR]

A microcalorimetric technique was used to evaluate the influence of Er3+ on Halobacterium halobium R1 growth. By means of a LKB-2277 Bioactivity Monitor ampoule method, we obtained the thermogenic curves of H. halobium R1 growth at 37 degrees C. In order to analyze the results, the relationship between k and C was obtained. The addition of Er3+ in low concentration cause a decrease of the maximum heat production Pmax and growth rate constants k; however, Er3+ in a high concentration might promote growth of H. halobium R1. When Er3+ is in a much higher concentration, the growth of H. halobium R1 is inhibited completely. For comparison, the shapes of H. halobium R1 cells were observed by means of transmission electron microscope (TEM). According to the thermogenic curves and TEM photos of H. halobium R1 under different conditions, it is clear that the metabolic mechanism of H. halobium R1 growth has been changed with the addition of Er3+.

A novel microcalorimetric technique based on the bacterial heat output was applied to evaluate the special growth model, the protein expression and the generation time of Bacillus thuringiensis for the first time. The thermogenic curves of the aerobic metabolism of B. thuringiensis strains YBT-833, YBT-1520 and YBT-833-2-1 were determined by using an LKB-2277 BioActivity Monitor. The analysis of the thermogenic curves indicated both the mutant strain and the wild-type strains followed the same linear growth model during sporulation. The metabolism heat output revealed heat output was correlated to the yield of the insecticidal crystal proteins (ICPs) very well, the more protein product, and the less heat output. Based on the data acquired, we proposed that this method could be a useful tool in monitoring the fermentation of B. thuringiensis.

By using an LKB-2277 Bioactivity Monitor, cycle-flow method, the thermogenic curves of aerobic growth for Bacillus thuringiensis cry II strain at 28 degrees C have been obtained. The metabolic thermogenic curves of B. thuringiensis cry II contained two distinct patterns: the first reflects the changes during the bacterial growth phase and the second corresponds to the sporulation phase. From these thermogenic curves in the absence and presence of Sm(3+) ions, the thermokinetic parameters such as the growth rate constants k, the interval time tau(I), the maximum power P (max 1) and heat-output Q(log) for log phase, the maximum power P (max 2) and heatoutput Q(stat) for stationary phase, the heat-output Q(spor) for sporulation phase and total heat effects QT are calculated. Sm(3+) ion has promoting action on the growth of B. thuringiensis cry II in its lower concentration range; on the other hand, this ion has inhibitory action on the sporulation of B. thuringiensis in its higher concentration range. We also found that the effects of Sm(3+) ion on B. thuringiensis during the sporulation phase were far greater than that during the bacterial phase. It is concluded that the application of B. thuringiensis for controlling insecticides is not affected by the presence of the rare-earth elements in the environmental ecosystem.

By using an LKB-2277 Bioactivity Monitor, ampoule mode, the heat output of Bacillus thuringiensis growth metabolism has been determined at 28 degrees C and effect of Cu2+ on B. thuringiensis growth was studied. Copper has been regarded as an essential trace element for life. Its deficiency may be the cause of diseases. Cu2+ of different concentration have different effects on B. thuringiensis growth metabolism, Cu2+ of low concentration (0-30 micrograms/ml) can promote the growth of B. thuringiensis, and Cu2+ of high concentration (40-120 micrograms/ml) is able to inhibit its growth and B. thuringiensis can't grow at all when the concentration of Cu2+ is up to 130 micrograms/ml.

The process that T4 phages multiply in host cells of Escherichia coli B was determined using LKB-2277 Bioactivity Monitor by means of stopped-flow method, and the growth was measured turbidometrically at the same time at 37 degrees C. By analyzing thermo-curves, quantitative parameters could be obtained to characterize the interactions of host cells and phages. The parameters such as k(a), P(max), G etc. change regularly with the decrease of multiplicity of infection (MOI) value. Infection-lysis equations were fitted and the lytic rate constant k(L) was obtained. The results show that the metabolic activity of infected cells is more intensive than that of normal cells. The phenomenon of lysis inhibition (LIN) was first detected with the microcalorimetric method, and the mechanism is discussed.

By using an LKB2277 Bioactivity Monitor, stop-flow mode, the power-time curves of Escherichia coli at 37 degrees C affected by Cu(II) were determined. Some parameters, such as growth rate constants k, inhibitory ratio I, the heat output Qlog in the log phase, and the generation times G were obtained. According to these parameters, we found that a low concentration of Cu(II) (0-20 microg/mL) had an promoting action on the growth of E. coli, but a high concentration of Cu(II) (40-100 microg/mL) had an inhibitory action. The toxicity of Cu(II) can also be expressed as the half-inhibitory concentration IC50; the value is 69.7 microg/mL. The assay is quantitative, inexpensive, and versatile.

The heat output of and the effect of manganese (II) on Tetrahymena shanghaiensis S199 growth metabolism has been determined by means of a LKB-2277 BioActivity monitor. Different concentrations of manganese(II) ions have different effects on the growth of T. shanghaiensis. At low concentrations (0-40 microg/mL) culture growth is promoted, whereas high concentrations (60-800 microg/mL) slow growth. Furthermore, concentrations of 1200 microg/mL or greater stop the growth of this protozooa completely.

A series of microcalorimetric experiments were performed to investigate the effect of La(3+) on the formation of the competent state of Escherichia coli HB101 by using a LKB-2277 BioActivity Monitor at 37 C. The thermogenic curves in the absence and in the presence of La(3+) were obtained. Based on these curves, we calculated that the total heat effects (Q(T)) and the maximal power (P(max)) in the presence and absence of La(3+). Our experiments indicate that the total heat effects in the presence of a low concentration of La(3+) (

The thermogenic curves of the metabolism of mitochondria isolated from the liver of chicken Star-Cross 288 and the effect of La3+ on it were studied by using an LKB-2277 BioActivity Monitor, ampoule method, at 37 degrees C. After isolation from the chicken liver tissue, mitochondria still have metabolic activity and can live for a long time by using the stored nutrients. From the thermogenic curves, we obtained the thermokinetic equations under different condition. The kinetic study shows that La3+ has changed the metabolism completely.

The heat output of the non-growth metabolism of Chlorella vulgaris has been determined using an LKB-2277 BioActivity Monitor. The experimental results indicate that there is a turn-point on the metabolic thermogenic curves, which can be divided into two parts, an early phase and a later phase. For the early phase, there is a linear relationship between the metabolic power (P) and the cell concentration (C), and that the heat output produced by a single cell's metabolism (P0) depends on the cell concentration (C) and is inhibited by the cell density, the thermokinetic equation of their metabolism is dP/dt = k0, k0 = 0.