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 8C. By analyzing thermocurves, quantitative parameters could be obtained to characterize the interactions of host cells and phages. The parameters such as ka, Pmax, G etc. change regularly with the decrease of multiplicity of infection (MOI) value. Infection/lysis equations were fitted and the lytic rate constant kL 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.

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

The thermogenic curves of the metabolism of mitochondria isolated from the heart of chicken Star-cross 288 and the e€ect of La3+ on it were studied by using an LKB-2277 BioActivity Monitor, ampoule method, at 37℃. After isolation from the chicken heart 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 di€erent conditions. The kinetics show that La3‡ has changed the metabolism completely.

The microcalorimetric bioassay for acute cellular toxicity is based on metabolic heat production from cultured cells. Microcalorimetry is a quantitative, inexpensive, and versatile method for toxicology research. The biological response to toxicants is the inhibition of the heat production rate in cells and toxicity is expressed as the concentration of toxicant that is 50% effective in this inhibition (IC50). In this paper, the effect of Cd2+on Rhizopus nigricans growth was investigated at 25℃ The relationship between growth rate constants (k) and concentration of Cd (C) shows a logarithmic normal distribution, and described as k=1.2742×1061 exp[-1.810×10-3 (C+2 283.0)2], and IC50 is 0.72μg/ml. These signals are readily obtained by an LKB 2277-204 heat 50 conduction microcalorimeter.

The effect of Na2SeO3 on the growth of Halobacterium halobium R1 was investigated by means of microcalorimetry at 37°C. The biological response to toxicants is observed as the inhibition of the rate constant of growth of living cells. A low concentration of Na2SeO3 stimulated the growth of H. halobium R1, and a high concentration of Na2SeO3 inhibited the growth of H. halobium R1. Toxicity may be expressed as the half-inhibition concentration (IC50). The rate constants of growth (k) and the concentrations of Na2SeO3 (c) shows a linear relationship: k=1.790×10-6-2.27×10-3c. The value of IC50 obtained from the accompanying figure of I-c is 679 μg/mL.