A microcalorimetric method for studying the toxic effect of different diphenol species on the growth of Escherichia coli.
A microcalorimetric technique based on bacterial heat-output was explored to evaluate the toxic effect of different diphenol species on the growth of Escherichia coli (E. coli). Power-time curves of the growth metabolism for E. coli in the presence of different diphenol species were studied using a multi-channel microcalorimetric system with an ampoule method at 37 degrees C. The growth rate constant (k), generation time (t(G)), inhibitory ratio (I), half-inhibitory concentration (IC(50)) and the total thermal effect (Q(T)) for E. coli were obtained. The results show that catechol and hydroquinone are more toxic to E. coli than resorcinol. In all cases, the growth rate constants of E. coli (in log phase) decreased as the concentrations of these diphenols increased. Among these diphenols species, catechol was found to be the most poisonous species at an IC(50) of 323.5 micro g/mL against E. coli. Hydroquinone exhibited moderate virulence with an IC(50) of 1196 micro g/mL and resorcinol had the lowest toxicity with an IC(50) of 2113 micro g/mL. The microcalorimetric bioassay can be a quantitative, inexpensive, and versatile method for acute cellular toxicity study.
Chen
Huilun
H
School of Environmental Studies and Key Laboratory of Biogeology and Environmental Geology of Chinese Ministry of Education, China University of Geosciences, Wuhan, PR China. chenhuilun_919@yahoo.com.cn
Yao
Jun
J
Wang
Yanxin
Y
Tian
Lin
L
Wang
Fei
F
Djak
Atakora
A
Choi
Martin M F
MM
Bramanti
Emilia
E
D000975:Antioxidants / Q000633:toxicity*; D002151:Calorimetry / Q000379:methods*; D002396:Catechols / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development*; D006873:Hydroquinones / Q000633:toxicity*; D007700:Kinetics; D012118:Resorcinols / Q000633:toxicity*; D013997:Time Factors
D000975:Antioxidants; D002396:Catechols; D006873:Hydroquinones; D012118:Resorcinols; C034221:catechol; C031927:hydroquinone; C031389:resorcinol