Interactions between pH, Potassium, Calcium, Bromide and Phenol and their effects on the Bioluminesc Print
Written by Thomas Liljedahl   
Tuesday, 23 February 2010 13:15
Interactions between pH, potassium, calcium, bromide and phenol and their effects on the bioluminescence of Vibrio fisheri

This study demonstrate that the ion composition and pH of the sample, as well as the diluents, should be considered when the toxicity of salts, water samples and extracts of sediments and soils are tested using commercially certified toxicity test kits.



Title: Interactions between pH, Potassium, Calcium, Bromide and Phenol and their effects on the Bioluminescence of Vibrio fischeri
Abstract Little attention has been paid to how the light produced by the bacterium Vibrio fischeri in the Microtox  assay is dependent on the concentration of essential ions such as sodium and potassium, and whether the concentrations of these ions affect the sensitivity of the test system to toxic chemicals. Five selected factors, pH, K+, Ca2+, Br- and phenol (Phe), were simultaneously varied over a set of systematically planned experiments according to a D-optimal design that supported the estimation of a model with linear, quadratic and two factor interations of the studied factors. The bacterial light production represented by the Gamma values in the Microtox assay for the 24 selected combinations of factors, were measured at 5 and 15 minutes. The Gamma values varied from negative to positive values greater than 1, indicating stimulation and inhibition of bacterial light production, respectively. The relationship between the Gamma values and the factor settings were investigated with multiple linear regression. After 5 min exposure, the light production was significantly affected by linear and quadratic terms for K+, pH and phenol and an interaction between Ph and phenol,. The situation was more complex after 15-min exposure, since in addition significant interactions were found between K*Phe and Ca*pH.. The tolerance of V. fischeri to phenol was enhanced by increasing the potassium and calcium concentrations. Data indicate that the ion composition and pH of the sample, as well as the diluents, should be considered when the toxicity of salts, water samples and extracts of sediments and soils are tested using commercially certified toxicity test kits. Authors:  Rune Berglind (Corresponding author) FOI CBRN Defence and Security, SE 901 82 Umeå Sweden Phone: +46 90 10 66 00; Fax: +46 90 106800 Email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it Per Leffler FOI CBRN Defence and Security, SE 901 82 Umeå Sweden Phone: +46 90 10 66 00; Fax: +46 90 10 68 00 Email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it Michael Sjöström Research Group for Chemometrics, Department of Chemistry, Umeå University. SE 901 87 Umeå, Sweden Phone: + 46 90 7865000; Fax: +46 90 7867655 Email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it   Reference: Jorna: J. Toxicol Environ. Health (Accepted 2010, January 4)
Last Updated on Wednesday, 24 February 2010 15:25