Increase in mitotic recombination in diploid cells of Aspergillus nidulans in response to ethidium bromide

Abstract

Ethidium bromide (EB) is an intercalating inhibitor of topoisomerase II and its activities are related to chemotherapeutic drugs used in anti-cancer treatments. EB promotes several genotoxic effects in exposed cells by stabilising the DNA-enzyme complex. The recombinagenic potential of EB was evaluated in our in vivo study by the loss of heterozygosity of nutritional markers in diploid Aspergillus nidulans cells through Homozygotization Index (HI). A DNA repair mutation, uvsZ and a chromosome duplication DP (II-I) were introduced in the genome of tested cells to obtain a sensitive system for the recombinagenesis detection. EB-treated diploid cells had HI values significantly greater than the control at both concentrations (4.0 x 10 -3 and 5.0 x 10 -3 µM). Results indicate that the intercalating agent is potentially capable of inducing mitotic crossing-over in diploid A. nidulans cells.

Identification of a mitotic recombination hotspot on chromosome III of the asexual fungus Aspergillus niger and its possible correlation elevated basal transcription

“…Possibly an increased rate of mitotic crossing-over could approach the advantages of meiotic recombination. In several organisms, mitotic crossing-over has been induced using heat shock, chemicals or irradiation (Becker et al 2003 ; Davies et al 1975 ; Hilton et al 1985 ; Jansen 1964 ; Klinner et al 1984 ; Sermonti and Morpurgo 1959 ; Whelan et al 1980 ). In order to examine the use of increasing mitotic recombination with effectors in A. niger , a chromosome specific tester strain would be very useful.…”

Myrothecium verrucariaisolates and formulations as bioherbicide agents for kudzu

“…Morphological variants or sectors are sometimes observed when fungi are cultured on artificial media (Jennings & Lysek 1996;Vannacci & Cristani 1998). This phenomenon has been attributed to genomic rearrangement, mutation, mycoviruses, and transposons (Flower & Milton 2000;Chu et al 2002;Firon et al 2002;Becker et al 2003 cultures, such as spore production and metabolite production (Guzman-de-Pena & Ruiz-Herra 1997; Chu et al 2002). Some phytopathogenic fungi that contain mycoviruses have reduced virulence (Chu et al 2002).…”

Influence of nutrition on the production and physiology of sectors produced by the insect pathogenic fungusMetarhizium anisopliae

“…Formation of distinct morphological variants or sectors is often observed in fungal cultures maintained on artificial media [1,2]. The type and frequency of sectoring varies among different fungal species and strains and has often been attributed to mutation, transposons, double‐stranded RNA mycoviruses and genomic rearrangements [3–7]. Some studies suggest that sectors arise as a result of cultural degeneration caused either by the age of culture, method of propagation, or nature of the culture medium [8–10].…”