Effect of gamma radiation on Aspergillus flavus and Aspergillus ochraceus ultrastructure and mycotoxin production

Ribeiro, Josimar; Cavaglieri, Lilia Reneé; Vital, Hélio de Carvalho; Cristofolini, Andrea; Merkis, Cecilia Inés; Astoreca, Andrea; Orlando, Julieta; Carú, Margarita; Dalcero, Ana María; Rosa, Carlos A.

doi:10.1016/j.radphyschem.2010.12.017

Cited by 27 publications

(18 citation statements)

References 19 publications

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“…However, exposure of Aspergillus sp. to the same gamma irradiation dose (2000 Gy) is not sufficient for the complete killing of spores (Ribeiro et al ). Regarding the effect of gamma irradiation on the production of digoxin, 1000 Gy was found to be the most effective dose that promoted the maximum production digoxin by the fungal strain.…”

Section: Discussionmentioning

confidence: 99%

A novel source of the cardiac glycoside digoxin from the endophytic fungus Epicoccum nigrum : isolation, characterization, production enhancement by gamma irradiation mutagenesis and anticancer activity evaluation

2019

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Aims Different endophytic fungi were isolated and screened for their digoxin‐producing ability. Strain improvement and different culture conditions were studied for more effective production of digoxin. Methods and Results Among the isolated fungi, an isolate produced digoxin in a concentration of 2·07 mg l−1. The digoxin‐producing fungal isolate was identified as Epicoccum nigrum Link according to the morphological features and phylogenetic analyses. The potentiality of the fungal strain for production enhancement of digoxin was performed by gamma radiation mutagenesis. Gamma irradiation dose of 1000 Gy intensified the digoxin yield by five‐fold. Using this dose, a stable mutant strain with improved digoxin productivity was isolated and the stability for digoxin production was followed up across four successive generations. In the effort to increase digoxin magnitude, selection of the proper cultivation medium, addition of some elicitors to the most proper medium and several physical fermentation conditions were tested. Fermentation process carried out in malt extract autolysate medium (pH 6·5) supplemented by methyl jasmonate and inoculated with 2 ml of 6‐day‐old culture and incubated at 25°C for 10 days stimulated the highest production of digoxin to attain 50·14 mg l−1. Moreover, cytotoxicity of digoxin separated from the fungal culture was tested against five different cancer cell lines. Based on the MTT assay, digoxin inhibited the proliferation of the five different cancer cell lines and the recorded 50% inhibitory concentration ranged from 10·76 to 35·14 μg ml−1. Conclusions This is the first report on the production and enhancement of digoxin using fungal fermentation as a new and alternate source with high productivity. Significance and Impact of the Study These findings offer new and alternate sources with excellent biotechnological potential for digoxin production by fungal fermentation. Moreover, digoxin proved to be a promising anticancer agent whose anticancer potential should be assessed in prospective cancer therapy.

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Section: Discussionmentioning

confidence: 99%

A novel source of the cardiac glycoside digoxin from the endophytic fungus Epicoccum nigrum : isolation, characterization, production enhancement by gamma irradiation mutagenesis and anticancer activity evaluation

2019

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“…Concerning the direct effect of ionizing radiation on fungal species, Ribeiro and others () studied the effect of gamma‐radiation (at 2 kGy) on A. flavus and on A. ochraceus . Irradiated strains showed different color and slight differences on the sizes of stipes, metulae, and conidia compared with the same nonirradiated strains.…”

Section: Irradiation To Control Mold Growth and Mycotoxinsmentioning

confidence: 99%

Irradiation for Mold and Mycotoxin Control: A Review

Calado

Venâncio

Abrunhosa

2014

Comp Rev Food Sci Food Safe

141

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The mycotoxin issue requires constant vigilance from economic, regulatory, and scientific agents to minimize its toxicological effects on human and animals. The implementation of good practices to avoid fungal growth and mycotoxin production on agricultural commodities is essential to achieve most restrictive safety standards; however, the contribution of novel technologies that may act on postharvesting and poststorage situations may be equally important. Several methodologies, more or less technologically advanced, may be used for this purpose. In this work, we review the role, contribution, and impact of irradiation technology to control the presence of fungi and mycotoxins in food and in feed. The effect of this technology on the viability of mold spores and on the elimination of mycotoxins is reviewed. A critical evaluation of the advantages and disadvantages of irradiation in this context is presented.

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“…Furthermore, it can be considered as an effective critical control point for most pathogens . Also, it is important to point out that the use of radiation treatment is complementary to good manufacturing practices and may constitute a strategy that could be applied together with other methodologies to prevent and control the presence of toxigenic fungi . In the last decade, several studies have reported the application of gamma radiation on different cereals such as wheat, barley, rice, maize and sorghum to control microbial growth .…”

Section: Introductionmentioning

confidence: 99%

“…11 Also, it is important to point out that the use of radiation treatment is complementary to good manufacturing practices and may constitute a strategy that could be applied together with other methodologies to prevent and control the presence of toxigenic fungi. 12 In the last decade, several studies have reported the application of gamma radiation on different cereals such as wheat, barley, rice, maize and sorghum to control microbial growth. 13 -22 The results showed that the response to radiation depends on various factors, including cereal type, microorganism type, initial microbial load, irradiation dose and dose rate.…”

Section: Introductionmentioning

confidence: 99%

Inactivation effect of electron beam irradiation on fungal load of naturally contaminated maize seeds

Nemţanu

Braşoveanu

Karaca

et al. 2014

J. Sci. Food Agric.

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Effect of gamma radiation on Aspergillus flavus and Aspergillus ochraceus ultrastructure and mycotoxin production

Cited by 27 publications

References 19 publications

A novel source of the cardiac glycoside digoxin from the endophytic fungus Epicoccum nigrum : isolation, characterization, production enhancement by gamma irradiation mutagenesis and anticancer activity evaluation

A novel source of the cardiac glycoside digoxin from the endophytic fungus Epicoccum nigrum : isolation, characterization, production enhancement by gamma irradiation mutagenesis and anticancer activity evaluation

Irradiation for Mold and Mycotoxin Control: A Review

Inactivation effect of electron beam irradiation on fungal load of naturally contaminated maize seeds

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