Biochemical mutagens affect the preservation of fungi and biodiversity estimations

Abstract

Many fungi have significant industrial applications or biosafety concerns and maintaining the original characteristics is essential. The preserved fungi have to represent the situation in nature for posterity, biodiversity estimations, and taxonomic research. However, spontaneous fungal mutations and secondary metabolites affecting producing fungi are well known. There is increasing interest in the preservation of microbes in Biological Resource Centers (BRC) to ensure that the organisms remain viable and stable genetically. It would be anathema if they contacted mutagens routinely. However, for the purpose of this discussion, there are three potential sources of biochemical mutagens when obtaining individual fungi from the environment: (a) mixtures of microorganisms are plated routinely onto growth media containing mutagenic antibiotics to control overgrowth by contaminants, (b) the microbial mixtures may contain microorganisms capable of producing mutagenic secondary metabolites, and (c) target fungi for isolation may produce "self" mutagens in pure culture. The probability that these compounds could interact with fungi undermines confidence in the preservation process and the potential effects of these biochemical mutagens are considered for the first time on strains held in BRC in this review.

Self mutagens affect detrimentally PCR analysis of food fungi by creating potential mutants

“…The mycotoxins with carcinogenic effects have been discussed in depth by the current authors (e.g. Paterson & Lima, 2013). However, some evidence will now be considered as these can be produced in culture during growth of food-related fungi.…”

“…The carcinogen compounds from fungi include aflatoxins, sterigmatocystin, ochratoxin A, fumonisin, zearalenone, citrinin, luteoskyrin, patulin, and penicillic acid (Table 1) produced by a wide range of fungi. These compounds may be self-mutagenic towards fungi (Paterson & Lima, 2013) and avoiding them during growth in vitro is necessary as they may affect the results of PCR analyses, in that normally positive strains for a gene may mutate to negative and vice versa. All the above compounds are DNA damaging agents except for fumonisins which may act via disturbing signal transduction pathways (Paterson & Lima, 2009.…”

“…However, a firm grounding in basic methods is required before the more novel procedures can be applied accurately (Editorial, 2013). PCR is used to analyse isolated fungi from food, or the food itself for particular fungi and much concern about fungi in food is from the production of mycotoxins which have powerful mutagenic activities causing cancers in animals and humans (Table 1) (Luch, 2006;Paterson & Lima, 2010). Interpretation of PCR results is equivocal because mutagenic secondary metabolites are produced by the target fungi in the growth media (Paterson & Lima, 2009Paterson, Sariah, Lima, Zainal Abidin, & Santos, 2008) and, for example, fungi which are normally positive for a mycotoxin, or other, gene may be mutated to negative.…”

Mutagens affect food and water biodeteriorating fungi

“…Numerous microorganisms can be co-isolated from food when attempting to isolate fungi, which may produce a large number of mutagenic secondary metabolites in agar at low concentrations ( Figure 1) [2 ]. The mutagenic load is made higher when antibiotics in the media are considered, which are at high concentrations to ensure antibiosis: chloramphenicol, gentamicin and cycloheximide are employed and are known mutagens [24][25][26] and mutagenic Rose Bengal is used frequently [27].…”

“…from food). Paterson and Lima [2 ] estimated 200 000 mutagenic compounds produced from all fungi. Furthermore, DNA in general may sustain 50 000 damages per cell per day and 150 000 oxidative adducts per cell generated through reactive oxidative species, which can cause mutations if uncorrected.…”