Studies on Aspergillus section Flavi isolated from maize in northern Italy

Giorni, Paola; Magan, Naresh; Pietri, Amedeo; Bertuzzi, Terenzio; Battilani, Paola

doi:10.1016/j.ijfoodmicro.2006.09.007

Cited by 226 publications

(163 citation statements)

References 25 publications

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“…None of the tested strains produced more AFB 2 than AFB 1 which is in accordance with Giorni et al [17]. However, two of the A. parasiticus strains synthesized more AFG 1 than AFB 1 .…”

Section: Discussionsupporting

confidence: 91%

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Aflatoxigenic Aspergillus flavus and Aspergillus parasiticus strains in Hungarian maize fields

Sebők¹,

Dobolyi²,

Zágoni³

et al. 2016

Acta Microbiologica et Immunologica Hungarica

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Due to the climate change, aflatoxigenic Aspergillus species and strains have appeared in several European countries, contaminating different agricultural commodities with aflatoxin. Our aim was to screen the presence of aflatoxigenic fungi in maize fields throughout the seven geographic regions of Hungary. Fungi belonging to Aspergillus section Flavi were isolated in the ratio of 26.9% and 42.3% from soil and maize samples in 2013, and these ratios decreased to 16.1% and 34.7% in 2014. Based on morphological characteristics and the sequence analysis of the partial calmodulin gene, all isolates proved to be Aspergillus flavus, except four strains, which were identified as Aspergillus parasiticus. About half of the A. flavus strains and all the A. parasiticus strains were able to synthesize aflatoxins. Aflatoxigenic Aspergillus strains were isolated from all the seven regions of Hungary. A. parasiticus strains were found in the soil of the regions Southern Great Plain and Southern Transdanubia and in a maize sample of the region Western Transdanubia. In spite of the fact that aflatoxins have rarely been detected in feeds and foods in Hungary, aflatoxigenic A. flavus and A. parasiticus strains are present in the maize culture throughout Hungary posing a potential threat to food safety.

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“…None of the tested strains produced more AFB 2 than AFB 1 which is in accordance with Giorni et al [17]. However, two of the A. parasiticus strains synthesized more AFG 1 than AFB 1 .…”

Section: Discussionsupporting

confidence: 91%

“…These results are in [17]. The presence of A. parasiticus has been reported for decades in several countries, especially in America and Asia [30][31][32][33], and recently it was detected in wheat in Slovakia [34], and in indoor air in Croatia [35].…”

Section: Discussionmentioning

confidence: 64%

Aflatoxigenic Aspergillus flavus and Aspergillus parasiticus strains in Hungarian maize fields

Sebők¹,

Dobolyi²,

Zágoni³

et al. 2016

Acta Microbiologica et Immunologica Hungarica

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“…They are produced by fungi of the genus Aspergillus (including Aspergillus flavus and Aspergillus parasiticus) in agricultural foodstuffs (maize, hazelnut, peanut, etc. ) (Giorni et al, 2007;Passone et al, 2010). These AFs are toxic and their main adverse effects on humans are hepatocarcinoma (Qian et al, 1994;IARC, 2014), immune system deficiency (Jiang et al, 2005), reduced child growth (Gong et al, 2004) and increased risks of stillborn or newborn jaundice (Shuaib et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Reduction of aflatoxin production by Aspergillus flavus and Aspergillus parasiticus in interaction with Streptomyces

et al. 2015

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The aim of this study is to investigate aflatoxin gene expression during Streptomyces-Aspergillus interaction. Aflatoxins are carcinogenic compounds produced mainly by Aspergillus flavus and Aspergillus parasiticus. A previous study has shown that Streptomyces-A. flavus interaction can reduce aflatoxin content in vitro. Here, we first validated this same effect in the interaction with A. parasiticus. Moreover, we showed that growth reduction and aflatoxin content were correlated in A. parasiticus but not in A. flavus. Secondly, we investigated the mechanisms of action by reversetranscriptase quantitative PCR. As microbial interaction can lead to variations in expression of household genes, the most stable [act1, btub (and cox5 for A. parasiticus)] were chosen using geNorm software. To shed light on the mechanisms involved, we studied during the interaction the expression of five genes (aflD, aflM, aflP, aflR and aflS). Overall, the results of aflatoxin gene expression showed that Streptomyces repressed gene expression to a greater level in A. parasiticus than in A. flavus. Expression of aflR and aflS was generally repressed in both Aspergillus species. Expression of aflM was repressed and was correlated with aflatoxin B1 content. The results suggest that aflM expression could be a potential aflatoxin indicator in Streptomyces species interactions. Therefore, we demonstrate that Streptomyces can reduce aflatoxin production by both Aspergillus species and that this effect can be correlated with the repression of aflM expression. INTRODUCTIONAflatoxins (AFs) are polyketide-derived furanocoumarins. They are produced by fungi of the genus Aspergillus (including Aspergillus flavus and Aspergillus parasiticus) in agricultural foodstuffs (maize, hazelnut, peanut, etc.) (Giorni et al., 2007;Passone et al., 2010). These AFs are toxic and their main adverse effects on humans are hepatocarcinoma (Qian et al., 1994; IARC, 2014), immune system deficiency (Jiang et al., 2005), reduced child growth (Gong et al., 2004) and increased risks of stillborn or newborn jaundice (Shuaib et al., 2010). To reduce those multiple effects, many countries have implemented maximum authorized levels of AFs in food and feed (Wu & Guclu, 2012). AF biosynthesis is coded by a 80 kb long DNA sequence. The latter is a cluster containing 30 putative genes characterized in both A. flavus and A. parasiticus (Yu, 2012). For structural genes, early (as aflD), medium (as aflM) and late (as aflP) genes are denominated (Fig. S1, available in the online Supplementary Material). The gene aflD encodes a reductase enzyme involved in the conversion of norsolorinic acid to averantin (Papa, 1982); aflM is required for the conversion of versicolorin A to demethylsterigmatocystin (Skory et al., 1992); and aflP encodes a methyltransferase converting sterigmatocystin to O-methylsterigmatocystin (Bhatnagar et al., 1988). Two cluster-specific regulators are also known: aflR encodes a transcription activator that binds a consensus sequence in the promoter regions of AF ...

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“…The stalk borer breaks open the physical barrier allowing the fungi to access the plant tissue. According to Giorni (2007) wounding of the kernels and stems by insects also reduces the moisture content and this favours the proliferation of A. flavus with subsequent aflatoxin production.…”

Section: Discussionmentioning

confidence: 99%

“…Insects infect kernels through the following ways; (i) they transport primary inoculum to the ears, (ii) they move inoculum from the silks into the ear, (iii) they disseminate inoculum within the ear and (iv) they wound intact tissue providing more infection sites. Wounding may also allow kernels to dry down to moisture levels that support the growth of Aspergillus and subsequent aflatoxin production (Giorni 2007, Samapundo 2006.…”

Section: Introductionmentioning

confidence: 99%

Colonization of stem borer damaged maize plants by aflatoxigenic Aspergillus species in Zimbabwe

Nleya¹,

Nyararai²,

Mawanza³

et al. 2017

Trop. Plant Res.

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Abstract:The worldwide contamination of food and feed with mycotoxins is a significant problem. Aflatoxins are major mycotoxins of agro-economic importance produced by some Aspergillus species. Aflatoxigenic Aspergillus species were isolated from insect larvae damaged maize stalks and characterized. The fungi were isolated from the stems, ears and silks of the plant. Aflatoxin production by the isolates was determined using the ammonium hydroxide method as well as the ultra violet fluorescence method. The Lepidopteran species feeding on the crop was identified as Busseola fusca. The Aspergillus species isolated were identified as Aspergillus flavus and Aspergillus parasiticus. This was done using macro-and microscopic features. A total of 35 isolates were obtained of which only 17 were aflatoxigenic. From the aflatoxigenic species 88% were A. parasiticus whilst 12% were A. flavus. Insects were however negative for aflatoxigenic fungi implying that these insects do not act as direct vectors of aflatoxigenic fungi, but however predispose the crop to fungal infection by damaging the physical barrier.

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Studies on Aspergillus section Flavi isolated from maize in northern Italy

Cited by 226 publications

References 25 publications

Aflatoxigenic Aspergillus flavus and Aspergillus parasiticus strains in Hungarian maize fields

Aflatoxigenic Aspergillus flavus and Aspergillus parasiticus strains in Hungarian maize fields

Reduction of aflatoxin production by Aspergillus flavus and Aspergillus parasiticus in interaction with Streptomyces

Colonization of stem borer damaged maize plants by aflatoxigenic Aspergillus species in Zimbabwe

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