Performances of three bacterial assays in toxicity assessment

Abstract

Three differing bacterial toxicity assays were compared: the 'Microtox' test, (Photobacterium phosphoreum luminescence inhibition assay), the 'oxygen consumption of activated sludge' assay (ISO 8192), and the 'Glucose U-14 C mineralization' assay (the rate of release of 4 CO2 by 'Escherichia col£). Metals, amines, halogenated alcans, chlorophenols, aromatic hydrocarbons, surfactants, and pesticides were screened for their toxic activity.Results showed satisfactory repeatability of the three bacterial assays with variation coefficients between 5 and 32%. The 'Microtox' assay was the most sensitive test evaluated under our conditions. The lower sensitivity of the 'oxygen consumption' assay may have been due to high concentrations of substrates which modify toxicant bioavailability, and also to a high biomass/toxic substances ratio. The 'Glucose U-4 C mineralization' assay was selective, and low in sensitivity; but the specific species used in this test -Escherichia coli -may have been responsible for this selectivity.The 'Microtox' test appears to be well adapted to the detection of aquatic environmental pollution, and to the toxicity screening of complex solid waste effluents and/or leachates. The 'oxygen consumption' assay can be advantageously used to measure the impact of sewage on activated sludge in biological treatment plants. The 'Glucose U-' 4 C mineralization' assay, which does not require high biomass, can be useful for in situ studies using field microorganisms.

Applications of Biosurfactants in the Petroleum Industry and the Remediation of Oil Spills

“…Microorganisms are useful in ecotoxicity testing because they may be evaluated over a short time and they occupy trophic levels in which bioaccumulation and/or bioconcentration are potential problems [ 74 ]. Bacterial toxicity tests measure a wide variety of endpoints including mutagenicity tests [ 75 ], population growth [ 76 ], CO 2 production [ 77 ], enzyme biosynthesis [ 78 ], glucose mineralization [ 79 ], and bioluminescence inhibition [ 80 ].…”

Interactions between accumulated copper, bacterial community structure and histamine levels in crayfish meat during storage

“…However, we did not culture microorganisms to establish relationships between identity and copper resistance, nor determined their histamine production potential. Considering (i) the relative low copper exposure concentrations applied in this study compared to the observed potentials to resist copper; (ii) the fact that the copper concentration in meat is only slightly enhanced after copper exposure; and (iii) that the bioavailable copper concentration in the digestive tract – the major habit for microorganisms – was not determined, it is difficult to evaluate the importance of resistance of bacteria to copper in relation to the observed community changes in water and meat. The effect of copper may also simply relates to the fitness of bacteria (e.g.…”

“…The effect of copper on microbial community structure in water may depend on several factors: among others, the exposure concentration, the chemical form of the toxic substance and species‐specific attributes to deal with copper . Many species of bacteria show resistance to copper: among others, Pseudomonas syringae, Xanthomonas campestris pv.…”

Influence of salinity on Vibrio fischeri and lux‐modified Pseudomonas fluorescens toxicity bioassays

“…The effective concentration of chemical or test sample causing a 50% inhibition of light (EC50) after a specified period of time (e.g., 15 min) is reported [3]. Use of the Microtox bioassay has been extensive and has included evaluation of many chemicals in aqueous solution [4–8], contaminated groundwaters and wastewaters [9–12], and aqueous and organic extracts of contaminated soils and sediments [13–16].…”