A short-term test adapted to detect the genotoxic effects of environmental volatile pollutants (benzene fumes) using the filamentous fungus Aspergillus nidulans

Abstract

With the recent focus on environmental problems, increasing awareness of the harmful effects of industrial and agricultural pollution has created a demand for progressively more sophisticated pollutant and toxicity detection methods. Using Aspergillus nidulans strains this work presents a new short term-test that, most importantly, enables the rapid and inexpensive detection of volatile pollutants that induce genotoxic/carcinogenic effects in animals. The main aim is to contribute to environmental health protection, and special attention is directed to monitoring the hazard posed by benzene (as a carcinogenic agent model) mainly because its ubiquitous presence often leads to severe noxious effects in humans among whom increased rates of human leukemia have been reported. To evaluate even the submutagenic effects of benzene fumes, two Aspergillus nidulans diploid strains, heterozygous for several auxotrophic mutations, were used. The DNA lesions produced stimulate mitotic recombination and homozygotization of auxotrophic recessive mutations. Conidial exposure to a saturated atmosphere of benzene fumes for 20 s was enough to increase the mitotic recombination frequencies significantly. Genetic analyses of treated diploids evidenced alterations related to mitotic recombination frequencies, gene expression, and allelic segregation rates. Altogether they reflect the potential of benzene to induce alterations in the fungal DNA, and albeit indirectly, they also respond for the genotoxic/carcinogenic harmful side effects widely connected to benzene. This is the first description of a sensitive, rapid and inexpensive test able to detect the submutagenic dose effects of volatile environmental compounds. In addition, despite concentrating on benzene the same test can be applied to many other pollutants, volatile or not. Additionally, the test can also be used to detect the antigenotoxic properties of foods and drugs.

Assessment of In Vivo and In Vitro Genotoxicity of Glibenclamide in Eukaryotic Cells

“…The recombinogenic potential of glibenclamide was evaluated by the homozygotization assay, a bioassay extensively used to detect the genotoxic effects of several chemical agents such as environmental volatile pollutants, herbicides, antidiabetic and cancer chemotherapeutic compounds [ 31 , 33 – 35 ]. Mitotic recombination due to non-sister chromatids exchange produces the loss of heterozygozity (LOH) for markers distal to the recombination site [ 36 ].…”

Metformin's performance in in vitro and in vivo genetic toxicology studies

“…The homozygotization assay using A. nidulans diploid cells is a bioassay extensively used to detect genotoxic effects of several physical and chemical agents such as X-rays, environmental volatile pollutants, herbicides and cancer chemotherapeutic compounds, thus providing relevant information about their recombinogenic potentials. 21,30, 44–46 A. nidulans is a filamentous fungus with a well-characterized genetic system whose cells spend most of their cell cycle in the G2 phase, a phase in which the chromosomes are duplicated, favouring the mitotic recombination event. 47 This study evaluated, for the first time, the recombinogenic potential of metformin by using the homozygotization assay.…”

Kaurenoic acid from Annona squamosa L. exhibits antiproliferative effect on human tumor cell lines and induces apoptosis in Aspergillus nidulans

“…According to D'Enfert [42] , germination is regulated by a large number of gene cascades, similar to what occurs in the embryogenesis of more complex organisms, marked by a set of morphogenetic events that reflect the expression of groups of genes and the type of influence that the environment can exert in this phase. Furthermore, assays with A. nidulans are able to identify the risks of genetic effects induced by environmental agents, such as a chemical agent or heterogeneous mixture [43][44][45][46][47][48][49] .…”