scholarly journals Host Factors Modulating Ochratoxin A Biosynthesis during Fruit Colonization by Aspergillus carbonarius

2020 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Uriel Maor ◽  
Omer Barda ◽  
Sudharsan Sadhasivam ◽  
Yang Bi ◽  
Varda Zakin ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Sugar Content ◽  
Grape Juice ◽  
Growth Conditions ◽  
Host Factors ◽  
Fungal Colonization ◽  
Toxic Metabolite ◽  
Aspergillus Carbonarius ◽  
The Impact

Aspergillus carbonarius is a strong and consistent ochratoxin A (OTA) producer and considered to be the main source of this toxic metabolite in grapes and grape products such as wine, grape juice and dried vine fruit. OTA is produced under certain growth conditions and its accumulation is affected by several environmental factors, such as growth phase, substrate, temperature, water activity and pH. In this study, we examined the impact of fruit host factors on regulation and accumulation of OTA in colonized grape berries, and assessed in vitro the impact of those factors on the transcriptional levels of the key genes and global regulators contributing to fungal colonization and mycotoxin synthesis. We found that limited sugar content, low pH levels and high malic acid concentrations activated OTA biosynthesis by A. carbonarius, both in synthetic media and during fruit colonization, through modulation of global regulator of secondary metabolism, laeA and OTA gene cluster expression. These findings indicate that fruit host factors may have a significant impact on the capability of A. carbonarius to produce and accumulate OTA in grapes.

Effect of Water Activity, Temperature, and Mixed Fungal Spore Interactions on Ochratoxin A Production by Aspergillus carbonarius

2015 ◽  
Vol 78 (2) ◽  
pp. 376-382 ◽  
Author(s):  
EFSTATHIA A. KOGKAKI ◽  
PANTELIS I. NATSKOULIS ◽  
GEORGE-JOHN E. NYCHAS ◽  
EFSTATHIOS Z. PANAGOU
Keyword(s):  
Ochratoxin A ◽  
Water Activity ◽  
Incubation Time ◽  
Interspecific Interactions ◽  
Grape Juice ◽  
Fungal Spore ◽  
Fungal Species ◽  
Aspergillus Carbonarius ◽  
Different Temperatures

The purpose of this work was to investigate the potential of two nontoxigenic Aspergillus section Nigri species (Aspergillus tubingensis and Aspergillus japonicus) to influence the in vitro ochratoxin A (OTA) production of three toxigenic Aspergillus carbonarius isolates (Ac-28, Ac-29, and Ac-33) from Greek vineyards of different geographical areas. OTA accumulation was evaluated by inoculation of 0:100, 25:75, 50:50, 75:25, and 100:0 ratios of mixed spore suspensions on a synthetic grape juice medium for up to 28 days at different temperatures (15, 20, and 25°C), water activity (aw) levels (0.95 and 0.98 aw) and incubation time (7, 14, 21, and 28 days). Results confirmed that environmental factors and fungal species had a significant effect on OTA production. Specifically, maximum OTA concentration for Ac-28 (3.21 μg g−1) and Ac-29 (7.69 μg g−1) was observed at 20°C/0.98 aw and for Ac-33 (9.13 μg g−1) at 15°C/0.95 aw, regardless of incubation time. Moreover, A. tubingensis had no significant influence on OTA concentration of all toxigenic isolates assayed, regardless of temperature, aw, and incubation time. On the other hand, the presence of A. japonicus slightly inhibited OTA production of Ac-29 and Ac-33, while for Ac-28, stimulation of OTA was observed in some cases. Overall, lower aw levels reduced OTA accumulation for Ac-28 and Ac-29, regardless of temperature, inoculum ratio, and time. On the contrary, for Ac-33, low aw increased OTA production, regardless of the investigated parameters. The importance of this study concerns the understanding of interspecific interactions on OTA diffusion by A. carbonarius in an attempt to find ways to prevent the presence of toxins in grapes and their derivatives.

Impact of Water Activity and Temperature on Growth and Ochratoxin A Production of Two Aspergillus carbonarius Isolates from Wine Grapes in Greece

2007 ◽  
Vol 70 (12) ◽  
pp. 2884-2888 ◽  
Author(s):  
CHRYSOULA C. TASSOU ◽  
PANTELIS I. NATSKOULIS ◽  
EFSTATHIOS Z. PANAGOU ◽  
APOSTOLOS E. SPIROPOULOS ◽  
NARESH MAGAN
Keyword(s):  
Ochratoxin A ◽  
Water Activity ◽  
Color Change ◽  
Fungal Growth ◽  
Grape Juice ◽  
Lag Phase ◽  
Aspergillus Carbonarius ◽  
Wine Grapes ◽  
Wine Production

The aim of this study was to determine the effects of water activity (aw; 0.85 to 0.98) and temperature (10 to 40°C) on the radial growth rate and ochratoxin A (OA) production of two Aspergillus carbonarius isolates in vitro. The isolates were obtained from wine grapes cultivated in Greece, and the trial was conducted with a synthetic grape juice medium similar in composition to grapes between veraison (beginning of color change) and ripeness. Fungal growth and OA production data were collected for 55 days. Response surface curves and cardinal values for aw and temperature were obtained using multiple regression analysis. The lag phase lasted from less than 1 to 10 days. Both isolates grew optimally at 30 to 35°C and 0.96 aw, but maximum OA production occurred under suboptimal growth conditions (15 to 20°C and 0.93 to 0.96 aw). Growth also was observed at 0.85 aw and 25°C, however at this same aw the fungus failed to produce mycelium at any other temperatures tested. The isolates produced OA at 15 to 30°C and 0.90 to 0.98 aw. Maximum OA production was detected after 25 days of incubation at 20°C and 0.96 aw and was 3.14 and 2.67 μgg−1, respectively, for the two strains. The isolated strains used in this study were more xerotolerant than others from the Mediterranean basin. These data will allow producers to identify and thus monitor critical environmental conditions effectively in wine grapes. These data also increase the knowledge base concerning the ability of A. carbonarius to grow and produce toxin under different ecological conditions and can contribute to the development of secondary models for the prediction and risk assessment of OA in wine production.

Effect of water activity and temperature on growth of Aspergillus carbonarius and Aspergillus tubingensis and their interactions on ochratoxin A production

2015 ◽  
Vol 8 (1) ◽  
pp. 99-105 ◽  
Author(s):  
M.L. Chiotta ◽  
D.M. Sosa ◽  
M.L. Ponsone ◽  
S.N. Chulze
Keyword(s):  
Ochratoxin A ◽  
Water Activity ◽  
Grape Juice ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Aspergillus Carbonarius ◽  
Aspergillus Tubingensis ◽  
Defence Reaction ◽  
Aspergillus Section

Aspergillus section Nigri are described as the main source of ochratoxin A (OTA) contamination in grapes and wine worldwide. The grape-growing area in Argentina has a wide latitudinal extension with ecological variations that allow the classification of well-demarcated regions. The aims of this study were: to determine the effect of eco-physiological parameters on growth of Aspergillus tubingensis and Aspergillus carbonarius and to evaluate the interaction between these species on OTA production in synthetic grape juice medium under different water activity (aw) and temperature conditions. The results showed that optimal growth conditions for A. tubingensis and A. carbonarius were 0.980 aw and 28 °C, however A. tubingensis grew faster than A. carbonarius at all temperatures and aw tested. OTA production by A. carbonarius was favoured at 20 °C and 0.950-0.965 aw, during 14 days of incubation. The effect of A. tubingensis on OTA production by A. carbonarius was mainly dependent on temperature. At 35 °C, A. tubingensis reduced the OTA production while this effect was not observed at 20 °C. More OTA could be produced as a defence reaction against fungal competitors to maintain niche colonisation, but in this study no effects by a related species were observed.

scholarly journals In-Vitro Application of a Qatari Burkholderia cepacia strain (QBC03) in the Biocontrol of Mycotoxigenic Fungi and in the Reduction of Ochratoxin A biosynthesis by Aspergillus carbonarius

Toxins ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 700 ◽  
Author(s):  
Randa Zeidan ◽  
Zahoor Ul-Hassan ◽  
Roda Al-Thani ◽  
Quirico Migheli ◽  
Samir Jaoua
Keyword(s):  
Antifungal Activity ◽  
Ochratoxin A ◽  
Burkholderia Cepacia ◽  
Culture Supernatant ◽  
Animal Health ◽  
Aspergillus Carbonarius ◽  
Penicillium Verrucosum ◽  
Wide Range ◽  
Mycotoxigenic Fungi

Mycotoxins are secondary metabolites produced by certain filamentous fungi, causing human and animal health issues upon the ingestion of contaminated food and feed. Among the safest approaches to the control of mycotoxigenic fungi and mycotoxin detoxification is the application of microbial biocontrol agents. Burkholderia cepacia is known for producing metabolites active against a broad number of pathogenic fungi. In this study, the antifungal potential of a Qatari strain of Burkholderia cepacia (QBC03) was explored. QBC03 exhibited antifungal activity against a wide range of mycotoxigenic, as well as phytopathogenic, fungal genera and species. The QBC03 culture supernatant significantly inhibited the growth of Aspergillus carbonarius, Fusarium culmorum and Penicillium verrucosum in PDA medium, as well as A. carbonarius and P. verrucosum biomass in PDB medium. The QBC03 culture supernatant was found to dramatically reduce the synthesis of ochratoxin A (OTA) by A. carbonarius, in addition to inducing mycelia malformation. The antifungal activity of QBC03’s culture extract was retained following thermal treatment at 100 °C for 30 min. The findings of the present study advocate that QBC03 is a suitable biocontrol agent against toxigenic fungi, due to the inhibitory activity of its thermostable metabolites.

Current Importance of Ochratoxin A–Producing Aspergillus spp.

2001 ◽  
Vol 64 (6) ◽  
pp. 903-906 ◽  
Author(s):  
M. L. ABARCA ◽  
F. ACCENSI ◽  
M. R. BRAGULAT ◽  
F. J. CABAÑES
Keyword(s):  
Ochratoxin A ◽  
Animal Health ◽  
Grape Juice ◽  
Poultry Meat ◽  
Aspergillus Ochraceus ◽  
Aspergillus Carbonarius ◽  
Penicillium Verrucosum ◽  
Closely Related Species ◽  
High Incidence ◽  
Food Commodities

Ochratoxin A (OA) is receiving attention worldwide because of the hazard it poses to human and animal health. OA contamination of commodities, such as cereals or pork and poultry meat, is well recognized. Nevertheless, there is an increasing number of articles reporting OA contamination in other food commodities, such as coffee, beer, wine, grape juice, and milk, in the last few years. This continuous and increasing exposure to OA that humans experience is reflected in the high incidence of OA in both human blood and milk in several countries. OA was believed to be produced only by Aspergillus ochraceus and closely related species of section Circumdati and by Penicillium verrucosum; however, in the genus Aspergillus, the production of OA has been recently reported by species outside the section Circumdati. Thus, it has been clearly established as a metabolite of different species of the section Nigri, such as Aspergillus niger and Aspergillus carbonarius. OA production ability by Aspergillus spp. is more widespread than previously thought; therefore, there is the possibility that unexpected species can be new sources of this mycotoxin in their natural substrates.

The effect of ambient pH modulation on ochratoxin A accumulation by Aspergillus carbonarius

2017 ◽  
Vol 10 (4) ◽  
pp. 339-348 ◽  
Author(s):  
U. Maor ◽  
S. Sadhasivam ◽  
V. Zakin ◽  
D. Prusky ◽  
E. Sionov
Keyword(s):  
Ochratoxin A ◽  
Molecular Mechanisms ◽  
Growth Conditions ◽  
Aspergillus Carbonarius ◽  
High Accumulation ◽  
Host Environment ◽  
Expression Of Genes ◽  
Regulatory Signal ◽  
Concomitant Reduction ◽  
Decay Development

Aspergillus carbonarius, the main cause of severe post-harvest decay of vine fruit, is considered the major source of ochratoxin A (OTA) contamination of grapes and derived products. The factors inducing OTA accumulation by A. carbonarius and its contribution to pathogenicity remain unclear. Present findings indicate that the production of organic acids, such as D-gluconic acid (GLA) and citric acid, by A. carbonarius in the growth medium or in the decayed fruit tissue was directly related to ambient pH reduction. Under these conditions, induced transcript expression of genes involved in OTA biosynthesis occurred concurrently with mycotoxin accumulation. The high accumulation of OTA during acidification process raised the question of its importance in host-pathogen interactions during the fungal colonisation. Treatment of colonised grapes with sodium bicarbonate reduced accumulation of organic acid and OTA with a concomitant reduction in decay development, suggesting that tissue acidification is a significant factor in A. carbonarius pathogenicity. The present findings suggest that ambient pH is a regulatory signal for induction of mycotoxin production by A. carbonarius under the dynamic nutritional growth conditions occurring in culture. Yet the molecular mechanisms of OTA biosynthesis induction during colonisation of the acidic host environment are still unclear and should be further investigated.

scholarly journals In Vitro Growth Conditions Boost Plant Lipid Remodelling and Influence Their Composition

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2326
Author(s):  
Sylwia Klińska ◽  
Sara Kędzierska ◽  
Katarzyna Jasieniecka-Gazarkiewicz ◽  
Antoni Banaś
Keyword(s):  
Lipid Metabolism ◽  
Growth Conditions ◽  
Plant Lipid ◽  
Acyl Lipid ◽  
Genetic Modifications ◽  
Acyl Lipids ◽  
In Vivo Growth ◽  
The Impact

Acyl-lipids are vital components for all life functions of plants. They are widely studied using often in vitro conditions to determine inter alia the impact of genetic modifications and the description of biochemical and physiological functions of enzymes responsible for acyl-lipid metabolism. What is currently lacking is knowledge of if these results also hold in real environments—in in vivo conditions. Our study focused on the comparative analysis of both in vitro and in vivo growth conditions and their impact on the acyl-lipid metabolism of Camelina sativa leaves. The results indicate that in vitro conditions significantly decreased the lipid contents and influenced their composition. In in vitro conditions, galactolipid and trienoic acid (16:3 and 18:3) contents significantly declined, indicating the impairment of the prokaryotic pathway. Discrepancies also exist in the case of acyl-CoA:lysophospholipid acyltransferases (LPLATs). Their activity increased about 2–7 times in in vitro conditions compared to in vivo. In vitro conditions also substantially changed LPLATs’ preferences towards acyl-CoA. Additionally, the acyl editing process was three times more efficient in in vitro leaves. The provided evidence suggests that the results of acyl-lipid research from in vitro conditions may not completely reflect and be directly applicable in real growth environments.

Effect of five fungicides on growth and ochratoxin A production by two Aspergillus carbonarius and Aspergillus niger isolated from Moroccan grapes

2014 ◽  
Vol 4 (3) ◽  
pp. 118-126
Author(s):  
Souad Zouhair ◽  
Souad Qjidaa Qjidaa ◽  
Atar Selouane ◽  
Driss Bouya ◽  
Cony Decock ◽  
...  
Keyword(s):  
Growth Rate ◽  
Ochratoxin A ◽  
Fungal Growth ◽  
Inhibitory Effect ◽  
Aspergillus Carbonarius ◽  
Total Inhibition ◽  
Germination And Growth ◽  
Dose Dependent Increase ◽  
Dose Dependent

Five fungicides azoxystrobin (ortiva), benomyl (benlate), hexaconazole (hexa), pyrimethanil (scala) and thiabendazole (tectocal) were tested sepa-rately in vitro for their ability to inhibit the growth of two ochratoxigenic strains of A. niger and A. carbonarius previously isolated from grapes. All fungicides effectively reduced the growth rate of A. carbonarius and A. niger from 34 to 100% at the recommended dose (RD). Thiabendazole caused total inhibition of spore germination and growth of the two strains, regardless of the doses assayed. Benomyl completely inhibited growth of A. niger whereas for A. carbonarius, concentrations above 0.02xRD were required to prevent the growth. The inhibitory effect of hexaconazole, azoxystrobin and pyrime-thanil was dose-dependent. At sub-lethal concentrations of three fungicides, a dose-dependent increase in in ochratoxin A biosynthesis by two strains was observed. The use of fungicide should be checked for its ability to inhibit fungal growth as well as for their effect in terms of mycotoxins biosynthesis.

scholarly journals Inhibition of ochratoxin A production of Aspergillus carbonarius by yeast species

2011 ◽  
Vol 29 (No. 3) ◽  
pp. 291-297
Author(s):  
I. Var ◽  
Z. Erginkaya ◽  
B. Kabak
Keyword(s):  
Ochratoxin A ◽  
Yeast Species ◽  
Grape Juice ◽  
Rhodotorula Glutinis ◽  
Aspergillus Carbonarius ◽  
Yeast Strains ◽  
Candida Famata ◽  
Candida Lusitaniae ◽  
Yeast Extract Sucrose ◽  
Potential Use

A total of 21 yeast strains isolated from wine-grapes of Turkey were screened for their ability to inhibit ochratoxin A (OTA) accumulation by Aspergillus carbonarius in both yeast extract sucrose (YES) broth and grape juice. In monoculture, A. carbonarius produced a mean level of 39.03 µg/l and 21.32 µg/l OTA when grown in YES medium and grape juice, respectively. However, its ability to produce OTA in YES medium was greatly reduced in the presence of yeast strains except for Candida lusitaniae E2, Kloeckera spp. E4, and Rhodotorula glutinis D6. The percentage of inhibition of OTA production in YES medium ranged between 4.67% and 99.87%. Similarly, OTA production was inhibited in grape juice by more than 50% in the presence of yeast strains apart from Candida famata E6, R. glutinis, C. famata O3, Kloeckera spp. B3, and C. lusitaniae D9. The present study highlights the potential use of yeast isolates in the biocontrol of ochratoxin A-producing A. carbonarius.

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