title: An in vitro microcalorimetric method for studying the toxic effect of cadmium on microbial activity of an agricultural soil.
abstract: Using TAM III multi-channel thermocalorimetry combined with direct microorganism counting (bacteria, actinomycetes and fungi) under laboratory conditions, we determined the microbial population count, resistance and activity toward cadmium (Cd) toxicity in soil. The thermokinetic parameters, which can represent soil microbial activity, were calculated from power-time curves of soil microbial activity obtained by microcalorimetric measurement. Simultaneous application of the two methods showed that growth rate constant (k), peak-heat output power (P (max)) and the number of living microorganisms decreased with increasing concentration of Cd. Anncrease in Cd concentration resulted in the decrease of the peak-heat output power and increase in the time of the peak of power. However, the relationships between the thermokinetic parameters (k and P (max)) and the number of microorganism were not linear, but the trend was similar. Our research also suggests that microcalorimetry is a very sensitive, simple and useful technique for in vitro investigation of the effects of toxic heavy metals on soil microbial activity.
authors.affiliation: School of Environmental Studies & MOE Biogeology and Environmental Geology Laboratory, China University of Geosciences, Wuhan 430074, P.R. China. junyao@cug.edu.cn
authors.forename: Jun
authors.initials: J
authors.lastname: Yao
authors.forename: Chaoqian
authors.initials: C
authors.lastname: Xu
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Tian
authors.forename: Yanxin
authors.initials: Y
authors.lastname: Wang
authors.forename: Huilun
authors.initials: H
authors.lastname: Chen
authors.forename: Zhou
authors.initials: Z
authors.lastname: Yong
authors.forename: Martin M F
authors.initials: MM
authors.lastname: Choi
authors.forename: Emilia
authors.initials: E
authors.lastname: Bramanti
authors.forename: Thomas
authors.initials: T
authors.lastname: Maskow
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D002104:Cadmium / Q000633:toxicity*; D002151:Calorimetry / Q000379:methods*; D002681:China; D015169:Colony Count, Microbial; D004784:Environmental Monitoring / Q000379:methods*; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000633:toxicity*; D013816:Thermodynamics
chemical_list: D012989:Soil Pollutants; D002104:Cadmium