title: Thermochemical studies of the toxic actions of heavy metal ions on Rhizopus nigricans.
abstract: By using a LKB2277 BioActivity Monitor (heat conduction microcalorimeter), stopped-flow method, the thermogenetic curves of Rhizopus nigricans growth at 25 degrees C inhibited by four kinds of heavy metal ions are determined, parameters such as growth rate constants k, inhibitory ratio I, half inhibitory concentration IC50 et al. are obtained. The experimental results show that heavy metal ions can inhibit Rhizopus nigricans growth obviously, low concentration of Cu2+ has promoting action. The inhibitory sequence is Cd2+ > Hg2+ > Pb2+ > Cu2+, half inhibitory concentration of them are Cd+ 0.8 micro g x ml(-1), Hg2+ 1.7 micro g x ml(-1), Pb2+ 48.0 micro g x ml(-1), Cu2+ 110 micro g x ml(-1). This microclorimetric bioassay for acute cellular toxicity is based on metabolic heat evolution from cultured cells. The assay is quantitative, inexpensive, and versatile; moreover, toxicological information can be obtained with cell from other species of interest.
authors.affiliation: Department of Chemistry, School of Life Sciences, Wuhan University, PR China.
authors.forename: Y
authors.initials: Y
authors.lastname: Cheng-Nong
authors.forename: L
authors.initials: L
authors.lastname: Yi
authors.forename: W
authors.initials: W
authors.lastname: Tian-Zhi
authors.forename: T
authors.initials: T
authors.lastname: Zhi-Qun
authors.forename: Q
authors.initials: Q
authors.lastname: Song-Sheng
authors.forename: S
authors.initials: S
authors.lastname: Ping
mesh_terms: D002151:Calorimetry; D019216:Metals, Heavy / Q000633:toxicity*; D012233:Rhizopus / Q000737:chemistry* / Q000187:drug effects* / Q000254:growth & development; D013816:Thermodynamics
chemical_list: D019216:Metals, Heavy