Bacterial test

The long latent periods involved in development of cancers make correlation of chemical exposures and disease extremely difficult. This can be countered pardy with tests on naturally short-Hved animals. Tests on bacteria, eg, the Ames test, may permit rapid detection of cancer potential, although there is no direct relationship between the results of bacterial tests and the effects of the tested chemicals on humans (56). 

Rashid KA, Mumma RO. 1984. Genotoxicity of methyl parathion in short-term bacterial test systems. 

Stainless steel disks are contaminated with a bacterial test suspension and dried. The disinfectant is applied on the dried film on the disk and kept at a specified temperature for a defined time. The disk is than transferred to a previously validated neutralization medium to stop the action of the disinfectant. The cfii of surviving bacteria recovered from the surface is determined quantitatively. 

The Ames salmonella-microsome test is a principal sensitive mutagen screening test. Compounds are tested on the mutants of Salmonella typhimurium for reversion from a histidine requirement back to prototrophy. A positive result is seen by the growth of revertant bacteria (which do not require an external histidine source). A microsomal activation system should be included in this assay. The use of five different bacterial test strains are generally required. 

A variety of methods are available to test a chemical for mutagenicity, i.e., its effect on the genetic material. The Ames Test has gained most recognition as a shortterm test [23],This is a bacterial test which allows fast performance and requires limited expense. Its correlation with the mutagenicity of mammals or even with a carcinogenic effect on mammals or humans has repeatedly been tested [24], but remains controversial. 

Qureshi, A.A., Flood, K.W., Thompson, S.R., Janhurst, S.M., Inniss, C.S., and Rokosh, D.A. Comparison of a luminescent bacterial test with other bioassays for determining toxicity of pure compounds and complex effluents, in Aquatic Toxicology and Hazard Assessment, Pearson, J.G., Foster, R.B., and Bishop, W.E., Eds. (Philadelphia, PA American Society for Testing and Materials, 1982), pp. 179-195. 

The bioluminescent direct contact flash test has been proposed as a modification of the direct contact luminescent bacterial test [24,38]. This method was developed for measuring the toxicity of solid and color samples, and involves kinetic measurements of luminescence started at the same time that the V. fischeri suspension is added to the sample. The luminiscence signal is measured 20 times per second during the 30 second exposure period. 

The bacterial mutant is mainly sensitive to metals and should therefore be used in conjunction with another bacterial test. This microbiotest is commercially available and is designed specifically for testing soils, sediments, and sludges. Semiquantitative results are obtained after three hours [40]. 

In mice exposure to 9 ppm caused a 50% decrease in respiratory rate. Lesions included ulceration and necrosis of the respiratory epithelium and moderate damage to lung tissue. Rats administered, via oral gavage, 10, 20, 40, or 80mg/kg for 10 consecutive days or 32 mg/kg for 90 consecutive days had inflammation, necrosis, acantholysis, hyperkeratosis, and epithelial hyperplasia of the forestomach. Chloropicrin was genotoxic in bacterial test systems."... 

Valeraldehyde caused chromosomal and DNA effects in mammalian cells in culture but was not mutagenic in an Ames bacterial test." ... 

Ames, B.N., Lee, F.D. and Durston, W.E. (1973) An improved bacterial test system for the detection and classification of mutagens and carcinogens. Proceeding of the National Academy of Sciences of the United States of America, 70, 782-786. 

Chloro-ort/20-toluidine gave variable results in the majority of bacterial tests for mutagenicity. While most of the mammalian tests were positive, chromosomal aberration assays gave conflicting results. These data overall indicate that 4-chloro-ort/2o-toluidine causes DNA damage in mammalian cells. 

Early hope that animal, and especially bacterial, tests would produce cheap and definitive information about the causes of cancer in humans has now faded. Disputes over tests are even more controversial than disputes over human evidence, and many scientists consider them unreliable. 

Which simple bacterial test can be used to detect mutagens ... 

No activity of benzoyl chloride was observed in single bacterial tests for either differential toxicity or mutation induction. 

Von Wright, A. Tikkanen, L. (1980) The comparative mutagenicities of hydrazine and its mono-and di-methyl derivatives in bacterial test systems. Mutat. Res., 78, 17-23... 

Bacterial mutagenesis tests have been conducted with distilled water solutions of the freeze-dried residues [concentrated up to 3000-fold (7)] and partially freeze-dried samples [concentrated 10-fold (49)]. High salt concentrations in such concentrates may cause toxicity problems in the bacterial tests. The use of dimethyl sulfoxide, methanol, or supercritical carbon dioxide to extract the organics from the freeze-dried residues for mutagenicity test purposes should be investigated. 

In a bacterial test system [ames test] no increase of mutagenicity was detected without or in presence of a metabolic system [3.213]. 

Shinohara, K. Lee, J.-H. Tanaka, M. Murakami, H. Omura, H. Mutagenicity of intermediates produced in the early stage of browning reaction of triose reductone with nucleic acid related compounds on bacterial tests. 

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