A comparison of three microbial assay procedures for measuring toxicity of chemical residues

Abstract-A simple and rapid test for screening and assessing the cytotoxicity of xenobiotics was developed with Tetrahymena pyriformis. The method estimates the activities of nonspecific esterases of a cell by concentrating within it a specific amount of fluorescence associated with fluorescein dye. The 1-h median effective concentration (EC50) values of 10 inorganic and eight organic substances are presented and compared to those of three other bioassays: the conventional T. pyriformis proliferation rate 9-h median inhibitory concentrations, the Microtox 30-min EC50s, and the Daphnia magna 4-methylumbelliferyl ␤-D galactoside 1-h EC50s. A highly significant correlation was found between the results obtained with the fluorescein diacetate test and those obtained with the growth inhibition and Microtox tests. This in vivo enzymatic test showed high sensitivity to all compounds tested except Cr 6ϩ and sodium dodecyl sulfate.

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“…Microtox and D. magna EC50 data reported in the literature [2,[18][19][20][21] are also presented in Table 1.…”

Section: Determination Of Ec50 Ic50 and Reproductibilitymentioning

confidence: 99%

Bioassay Technique Using Nonspecific Esterase Activities of Tetrahymena Pyriformis for Screening and Assessing Cytotoxicity of Xenobiotics

Bogaerts¹,

Sénaud²,

Bohatier³

1998

Environ Toxicol Chem

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“…'Based on inhibition of bioluminescence (Chang et al, 1981;Qureshi et al, 1982; dBased on lethality (LeBlanc, 1980;Qureshi et al, 1982;McFeters et al, 1983). Plotkin and Ram, 1984;Greene et al, 1985). Bitton et al, unpublished. limited permeability of wild-type E .…”

Section: Comparison Of Enzyme Biosynthesis To Other Toxicity Testsmentioning

confidence: 99%

Enzyme biosynthesis versus enzyme activity as a basis for microbial toxicity testing

Dutton

Bitton

Koopman

1988

Environ. Toxicol. Water Qual.

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A toxicity assay based on inhibition of β‐galactosidase biosynthesis was compared to a similar assay based on inhibition of β‐galactosidase activity. In both tests, Escherichia coli grown in a minimal medium was exposed to isopropyl‐β‐thiogalactoside to induce β‐galactosidase biosynthesis. The induction step preceded contact of cells with the toxicant in the enzyme activity assay, whereas in the enzyme biosynthesis test, the inducer was added following contact of cells with the toxicant. Relative sensitivity was judged on the basis of responses to the heavy metals Hg2+, Cu2+, and Cd2+, and the organics 3,4‐dichlorophenol, formaldehyde, Hydrothol, phenol, sodium dodecyl sulphate, and toluene. Comparison of these results to the IC50s achieved with other microbial systems, Daphnia bioassay, and fish bioassay indicates that the enzyme activity test was moderately sensitive to heavy metals but was insensitive to organic toxicants. The test based on inhibition of enzyme biosynthesis was sensitive to both heavy metals and toxic organics.

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“…Dutka et al (1983) obtained a Microtox 15-min EC50 value of 3.8 mg Cu/L, with toxicity increasing with increasing exposure time. Using 30 tests with Microtox and copper, Greene et al (1985) reported an average EC50 value of 1.2 mg Cu/L, 30-fold greater than the EC50 concentrations of the protozoan chemoattraction assay. Table IV shows comparisons of results using T .…”

Section: Resultsmentioning

confidence: 89%

Effect of copper, herbicides, and a mixed effluent on chemoattraction of tetrahymena pyriformis

Roberts

Berk

1993

Environ. Toxicol. Water Qual.

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The inhibitory effect of copper, 2,4‐D, Roundup, and an industrial effluent on chemoattraction responses of the ciliate Tetrahymena pyriformis was examined using a microcapillary technique. Each toxicant was tested with four replicates on three separate occasions. All toxicants inhibited chemoattraction at sublethal concentrations; although at lower concentrations of the herbicides, complete recovery to control levels was observed with longer exposures. Results indicate that sublethal concentrations of certain chemical pollutants may interfere with the ciliate's motility or chemosensory abilities. This may ultimately affect the ecosystem by inhibiting their ability to maintain their population levels and roles in the environment.

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A comparison of three microbial assay procedures for measuring toxicity of chemical residues

Cited by 53 publications

References 6 publications

Bioassay Technique Using Nonspecific Esterase Activities of Tetrahymena Pyriformis for Screening and Assessing Cytotoxicity of Xenobiotics

Bioassay Technique Using Nonspecific Esterase Activities of Tetrahymena Pyriformis for Screening and Assessing Cytotoxicity of Xenobiotics

Enzyme biosynthesis versus enzyme activity as a basis for microbial toxicity testing

Effect of copper, herbicides, and a mixed effluent on chemoattraction of tetrahymena pyriformis

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