| Mutagenicity of tryptophan photoproducts in the Ames Salmonella assay. | |
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MedLine Citation:
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PMID: 7515161 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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During the photolysis of tryptophan a large number of products is formed. In this study, aqueous solutions of tryptophan were irradiated by ultraviolet light during 5, 20 or 40 h. Each of the irradiated batches was divided into two aliquots, which were freeze-dried or extracted with chloroform. For each batch the latter extract was subsequently divided into a purified chloroform extract and a methanol extract. Aliquots of the purified chloroform extracts were fractionated and pooled, peakwise, into seven fractions. A recombined sample was also constructed. All extracts and samples were tested for mutagenicity using the standard Ames Salmonella assay. The results indicate an exposure time dependent increase in mutagenicity of the extracts, as seen with tester strain TA100 both with and without metabolic activation. The mutagenicity of the freeze-dried extracts well approximated the mutagenicity of the chloroform extracts, indicating that most mutagenicity can be extracted with chloroform. With the fractions the highest mutagenic responses were seen in the late, i.e., less lipophilic fractions. This response pattern seen in TA98 and TA100, mainly with S9 activation, was in contrast to the response of TA102 without S9, which was highest to the more lipophilic fractions. On a fraction level, no general exposure dependent increase of mutagenicity was observed. The results also show that photooxidation of tryptophan gives rise to a different spectrum of products compared to pyrolysis. Both processes result in compounds with strong biological effects. Photooxidation results in compounds with low genotoxicity and high Ah receptor affinity while pyrolysis generates compounds with high genotoxicity and low or no Ah receptor affinity. |
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Authors:
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M Sjögren; U Sjöberg; U Rannug |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Mutation research Volume: 321 ISSN: 0027-5107 ISO Abbreviation: Mutat. Res. Publication Date: 1994 Jun |
Date Detail:
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Created Date: 1994-06-28 Completed Date: 1994-06-28 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0400763 Medline TA: Mutat Res Country: NETHERLANDS |
Other Details:
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Languages: eng Pagination: 229-39 Citation Subset: IM |
Affiliation:
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Department of Genetic and Cellular Toxicology, Wallenberg Laboratory, Stockholm University, Sweden. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Biotransformation Chloroform Freeze Drying Hot Temperature Mutagenicity Tests Mutagens / isolation & purification, toxicity* Oxidation-Reduction Photolysis* Receptors, Aryl Hydrocarbon / metabolism Salmonella typhimurium / drug effects, genetics Tryptophan / chemistry*, radiation effects* Ultraviolet Rays |
| Chemical | |
Reg. No./Substance:
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0/Mutagens; 0/Receptors, Aryl Hydrocarbon; 67-66-3/Chloroform; 73-22-3/Tryptophan |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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