Mutagenic Pollutants Research Articles

Acetyl coenzyme A-dependent binding of carcinogenic and mutagenic dinitropyrenes to DNA

Dinitropyrenes are mutagenic and carcinogenic environmental pollutants found in diesel emissions and urban air particulates. In Salmonella typhimurium these compounds appear to be activated to mutagens by sequential nitroreduction and acetylation. We have examined whether or not similar activation pathways occur with mammalian nitroreductases and acetylases. When rat liver cytosol, NADPH and calf thymus DNA were incubated with [4,5,9,10(-3)H]1-nitropyrene, [4,5,9,10(-3)H]1,3-, 1,6- or 1,8-dinitropyrene very low levels of nitrated pyrene binding with DNA were detected. Addition of acetyl coenzyme A (AcCoA) to these incubations increased the binding of dinitropyrenes 20- to 40-fold while the binding of 1-nitropyrene was not affected. The extent of AcCoA-dependent binding of dinitropyrenes reflected the amount of nitroreduction, as measured by aminonitropyrene formation. However, the increase in binding of dinitropyrenes to DNA in the presence of AcCoA did not occur with dog liver cytosol which is known to be deficient in N-acetylases. These results suggest that cytosolic nitroreductases catalyze the formation of N-hydroxy arylamine intermediates which in the case of dinitropyrenes are converted to reactive N-acetoxy arylamines by cytosolic AcCoA-dependent acetylases.

The detection of mutagenic pollutants in marine organisms of Kuwait

Several types of pollutants are currently entering the territorial waters of Kuwait from a variety of sources. Some pollutants, especially petrochemicals, are known to be potentially mutagenic and/or carcinogenic. Some of these chemical pollutants may enter the tissues of aquatic organisms and eventually the human body. The presence of such chemicals in the marine environment might create a serious health hazard. The marine environment of Kuwait was monitored for the presence of mutagenic chemicals using living organisms such as shrimp, clams and algae as bioindicators. These organisms were collected from selected sites within Kuwait territorial waters. Their tissues were extracted in ethanol and screened for genetically active chemicals by two standard bacterial assays, the Fluctuation Test and the Ames Test. Salmonella typhimurium TA98 was used as a tester strain. The data obtained from this study indicated that the shrimp, algae and clam samples were polluted with low concentration of frameshift mutagens. Due to the limited scope and nature of this study it was impossible to determine the source(s) of input or the chemical nature of these pollutants.

Monitoring the coastal waters of Kuwait for chemical mutagens

Industrial and municipal effluents are currently dumped in the coastal waters of Kuwait. They contain a variety of pollutants, some of which are potentially mutagenic and/or carcinogenic. For detection of these pollutants, marine algae (seaweeds) and clams were used as bioindicators of pollutants in the marine environment. Bacterial mutagenicity assays using fluctuation analysis and the Ames test were used to detect both frameshift and basechange mutagens. The results suggest that the majority of sites along the coast of Kuwait are polluted with low concentrations of mutagenic pollutants. The sources of input and the chemical nature of these pollutants were not determined.

Screening aquatic ecosystems for mutagens with fern bioassays.

Recent researches on the royal fern, Osmunda regalis, have documented a high incidence of post-zygotic mutational damage in a population growing in a river heavily polluted with paper processing wastes, whereas genetic studies of nearby populations in nonpolluted environments failed to detect mutational damage. Intensive genetic and cytogenetic studies of mutation in O. regalis indicates that natural populations of homosporous ferns may be useful in situ bioassay systems for monitoring the presence of mutagens in aquatic ecosystems. Since these organisms are long-lived perennials with an ontogenetic system which stores mutational damage, they can be manipulated to give an integrated estimate of mutational damage for specified blocks of time (in units of years). Thus, the fern bioassay may be an inexpensive means of detecting both chronic low dose and episodic high dose inputs of mutagenic pollutants into aquatic ecosystems. The fern mutagen bioassay is based upon the detection of numerous categories of post-zygotic mutation load in natural fern populations. The frequency of sporophytic and embryonic lethals, leaf or root mutations, auxotrophic gametophytic mutations as well as numerous phenotypic alterations of gametophyte morphology can be routinely detected and quantified. In addition, various two-break chromosome aberrations (paracentric inversions, reciprocal translocations and ring chromosomes) can be readily screened for in the spore mother cells of many homosporous ferns.