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Prof. Ali Atoui
Professor of Microbiology at Lebanese University - Faculty of Sciences

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0 Mycotoxins
0 mycotoxigenic fungi
0 secondary metabolites
0 Fungal Biology
0 Mycotoxin control

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secondary metabolites
mycotoxigenic fungi

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Review
Published: 12 December 2020 in International Journal of Molecular Sciences
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Penicillium, one of the most common fungi occurring in a diverse range of habitats, has a worldwide distribution and a large economic impact on human health. Hundreds of the species belonging to this genus cause disastrous decay in food crops and are able to produce a varied range of secondary metabolites, from which we can distinguish harmful mycotoxins. Some Penicillium species are considered to be important producers of patulin and ochratoxin A, two well-known mycotoxins. The production of these mycotoxins and other secondary metabolites is controlled and regulated by different mechanisms. The aim of this review is to highlight the different levels of regulation of secondary metabolites in the Penicillium genus.

ACS Style

Christelle El Hajj Assaf; Chrystian Zetina-Serrano; Nadia Tahtah; André El Khoury; Ali Atoui; Isabelle P. Oswald; Olivier Puel; Sophie Lorber. Regulation of Secondary Metabolism in the Penicillium Genus. International Journal of Molecular Sciences 2020, 21, 9462 .

AMA Style

Christelle El Hajj Assaf, Chrystian Zetina-Serrano, Nadia Tahtah, André El Khoury, Ali Atoui, Isabelle P. Oswald, Olivier Puel, Sophie Lorber. Regulation of Secondary Metabolism in the Penicillium Genus. International Journal of Molecular Sciences. 2020; 21 (24):9462.

Chicago/Turabian Style

Christelle El Hajj Assaf; Chrystian Zetina-Serrano; Nadia Tahtah; André El Khoury; Ali Atoui; Isabelle P. Oswald; Olivier Puel; Sophie Lorber. 2020. "Regulation of Secondary Metabolism in the Penicillium Genus." International Journal of Molecular Sciences 21, no. 24: 9462.

Article
Published: 26 November 2020 in European Journal of Plant Pathology
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Zearalenone (ZEN) is a mycotoxin produced by some species of Fusarium, especially by Fusarium graminearum and F. culmorum. It is a significant contaminant of maize, barley, wheat and other cereals. ZEN is implicated in reproductive problems in experimental animals and livestock and is classified as a non-steroidal estrogen or mycoestrogen. The carcinogenicity, genotoxicity, hepatotoxicity, haematotoxicity and immunotoxicity of ZEN were also reported. ZEN is biosynthesized from acetate-polymalonate pathway leading to nonaketide precursor which then subjected to different cyclizations and modifications. At the molecular level, a 50 kb gene cluster containing 11 genes was previously identified in F. graminearum. But ZEN biosynthesis is limited to four genes within this cluster: two polyketide synthase genes PKS4 and PKS13, gene similar to isoamyl alcohol oxidase (ZEB1) and a regulatory protein gene (ZEB2). This review covers the updated information concerning the molecular biology of ZEN biosynthesis as well as the proposed mechanism of its biosynthetic pathway. We also report the molecular regulation of its biosynthesis. Moreover, molecular methods developed for the specific detection and quantification of ZEN producing species are detailed in this review.

ACS Style

Sahar Nahle; André El Khoury; Ali Atoui. Current status on the molecular biology of zearalenone: its biosynthesis and molecular detection of zearalenone producing Fusarium species. European Journal of Plant Pathology 2020, 159, 247 -258.

AMA Style

Sahar Nahle, André El Khoury, Ali Atoui. Current status on the molecular biology of zearalenone: its biosynthesis and molecular detection of zearalenone producing Fusarium species. European Journal of Plant Pathology. 2020; 159 (2):247-258.

Chicago/Turabian Style

Sahar Nahle; André El Khoury; Ali Atoui. 2020. "Current status on the molecular biology of zearalenone: its biosynthesis and molecular detection of zearalenone producing Fusarium species." European Journal of Plant Pathology 159, no. 2: 247-258.

Journal article
Published: 16 August 2020 in International Journal of Food Microbiology
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Salmonella enterica subsp. enterica serovars are considered major causes of food poisoning and we performed this study because Salmonella is a burden in Lebanon. The present study investigated the ability of genomic information to predict serovar using a collection of Salmonella isolates from infected humans (n = 24) and contaminated food (n = 63) in Lebanon. Further, the phylogenomic relationships of the serovar the predominated in Lebanon (i.e., S. Enteritidis; n = 25) were investigated in comparison with isolates from other countries (n = 130) based on coregenome single nucleotide polymorphisms (SNPs). Genetic elements, specifically Salmonella pathogenicity islands (SPI), plasmid replicons, and antibiotic-resistance genes were screened in S. Enteritidis genomes (n = 155). Our results revealed that the Salmonella serovars identification by seroagglutination from the samples isolated in Lebanon (n = 87) was highly correlated with the genomic-based prediction of serovars (80.4–85.0% with SeqSero1 and 93.1–94.2% with SeqSero2). The Salmonella serovars isolated from human and food samples in Lebanon were mainly Enteritidis (28.7%) and Infantis (26%). To a rare extent, other serovars included Amager, Anatum, Bredeney, Chincol, Heidelberg, Hofit, Kentucky, Montevideo, Muenster, Newport, Schwarzengrund, Senftenberg and Typhimurium. In comparison with other countries, S. Enteritidis samples isolated in Lebanon (56 ± 27 intra-group pairwise SNP differences) presented a strong phylogenomic relativeness at the coregenome level with samples, as for example with samples isolated from Syria (65 ± 31 inter-group pairwise SNP differences). Most of the studied S. Enteritidis genomes encoded 10 SPIs involved in survival in immune cells (i.e. SPIs 1, 2, 3, 4, 5, 12, 13, 14, 16 and 17). The plasmid replicons IncFIB (S)_1 and IncFII (S)_1 encoding elements involved in virulence were identified in the majority of the S. Enteritidis genomes (94% and 96%, respectively), the majority exhibiting aminoglycosides (gene aac(6′)-Iaa_1). The IncI_1_Alpha replicon responsible for ampicillin-resistance was only detected in 2 of 155 Lebanese human clinical strains. Genomic-based risk assessment of Salmonella serovars in Lebanon showed that food imported from Syria might be an origin of the S. Enteritidis human cases in Lebanon. The detection of several SPIs involved in the survival, plasmid replicons involved in virulence, and aminoglycoside-resistance genes, emphasizes that S. Enteritidis is of paramount importance for public health in Lebanon and other countries.

ACS Style

Marie Noel Mansour; Joseph Yaghi; André El Khoury; Arnaud Felten; Michel-Yves Mistou; Ali Atoui; Nicolas Radomski. Prediction of Salmonella serovars isolated from clinical and food matrices in Lebanon and genomic-based investigation focusing on Enteritidis serovar. International Journal of Food Microbiology 2020, 333, 108831 .

AMA Style

Marie Noel Mansour, Joseph Yaghi, André El Khoury, Arnaud Felten, Michel-Yves Mistou, Ali Atoui, Nicolas Radomski. Prediction of Salmonella serovars isolated from clinical and food matrices in Lebanon and genomic-based investigation focusing on Enteritidis serovar. International Journal of Food Microbiology. 2020; 333 ():108831.

Chicago/Turabian Style

Marie Noel Mansour; Joseph Yaghi; André El Khoury; Arnaud Felten; Michel-Yves Mistou; Ali Atoui; Nicolas Radomski. 2020. "Prediction of Salmonella serovars isolated from clinical and food matrices in Lebanon and genomic-based investigation focusing on Enteritidis serovar." International Journal of Food Microbiology 333, no. : 108831.

Review
Published: 28 February 2020 in Toxins
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The study of fungal species evolved radically with the development of molecular techniques and produced new evidence to understand specific fungal mechanisms such as the production of toxic secondary metabolites. Taking advantage of these technologies to improve food safety, the molecular study of toxinogenic species can help elucidate the mechanisms underlying toxin production and enable the development of new effective strategies to control fungal toxicity. Numerous studies have been made on genes involved in aflatoxin B1 (AFB1) production, one of the most hazardous carcinogenic toxins for humans and animals. The current review presents the roles of these different genes and their possible impact on AFB1 production. We focus on the toxinogenic strains Aspergillus flavus and A. parasiticus, primary contaminants and major producers of AFB1 in crops. However, genetic reports on A. nidulans are also included because of the capacity of this fungus to produce sterigmatocystin, the penultimate stable metabolite during AFB1 production. The aim of this review is to provide a general overview of the AFB1 enzymatic biosynthesis pathway and its link with the genes belonging to the AFB1 cluster. It also aims to illustrate the role of global environmental factors on aflatoxin production and the recent data that demonstrate an interconnection between genes regulated by these environmental signals and aflatoxin biosynthetic pathway.

ACS Style

Isaura Caceres; Anthony Al Khoury; Rhoda El Khoury; Sophie Lorber; Isabelle P. Oswald; André El Khoury; Ali Atoui; Olivier Puel; Jean-Denis Bailly. Aflatoxin Biosynthesis and Genetic Regulation: A Review. Toxins 2020, 12, 150 .

AMA Style

Isaura Caceres, Anthony Al Khoury, Rhoda El Khoury, Sophie Lorber, Isabelle P. Oswald, André El Khoury, Ali Atoui, Olivier Puel, Jean-Denis Bailly. Aflatoxin Biosynthesis and Genetic Regulation: A Review. Toxins. 2020; 12 (3):150.

Chicago/Turabian Style

Isaura Caceres; Anthony Al Khoury; Rhoda El Khoury; Sophie Lorber; Isabelle P. Oswald; André El Khoury; Ali Atoui; Olivier Puel; Jean-Denis Bailly. 2020. "Aflatoxin Biosynthesis and Genetic Regulation: A Review." Toxins 12, no. 3: 150.

Review
Published: 29 May 2019 in Toxins
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Aflatoxins (AF) are carcinogenic metabolites produced by different species of Aspergillus which readily colonize crops. AFM1 is secreted in the milk of lactating mammals through the ingestion of feedstuffs contaminated by aflatoxin B1 (AFB1). Therefore, its presence in milk, even in small amounts, presents a real concern for dairy industries and consumers of dairy products. Different strategies can lead to the reduction of AFM1 contamination levels in milk. They include adopting good agricultural practices, decreasing the AFB1 contamination of animal feeds, or using diverse types of adsorbent materials. One of the most effective types of adsorbents used for AFM1 decontamination are those of microbial origin. This review discusses current issues about AFM1 decontamination methods. These methods are based on the use of different bio-adsorbent agents such as bacteria and yeasts to complex AFM1 in milk. Moreover, this review answers some of the raised concerns about the binding stability of the formed AFM1-microbial complex. Thus, the efficiency of the decontamination methods was addressed, and plausible experimental variants were discussed.

ACS Style

Jean Claude Assaf; Sahar Nahle; Ali Chokr; Nicolas Louka; Ali Atoui; André El Khoury. Assorted Methods for Decontamination of Aflatoxin M1 in Milk Using Microbial Adsorbents. Toxins 2019, 11, 304 .

AMA Style

Jean Claude Assaf, Sahar Nahle, Ali Chokr, Nicolas Louka, Ali Atoui, André El Khoury. Assorted Methods for Decontamination of Aflatoxin M1 in Milk Using Microbial Adsorbents. Toxins. 2019; 11 (6):304.

Chicago/Turabian Style

Jean Claude Assaf; Sahar Nahle; Ali Chokr; Nicolas Louka; Ali Atoui; André El Khoury. 2019. "Assorted Methods for Decontamination of Aflatoxin M1 in Milk Using Microbial Adsorbents." Toxins 11, no. 6: 304.

Original research
Published: 28 January 2019 in International Journal of Dairy Technology
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This study aimed to develop a new method for detoxification of milk from aflatoxin M1 (AFM1) by using Lactobacillus rhamnosus GG biofilm. After inoculation of milk contaminated with AFM1 into L. rhamnosus GG biofilm, the unbound AFM1 was extracted and quantified by HPLC. The stability of the formed AFM1/biofilm complex using different AFM1 contamination levels of milk was also studied. We found that the percentages of bound AFM1 by L. rhamnosus GG biofilm reached up to 60.74%. While no significant difference in milk proteins content was observed after AFM1 binding, some changes in total dry matter and fat content were noticed.

ACS Style

Jean Claude Assaf; Andre EL Khoury; Ali Chokr; Nicolas Louka; Ali Atoui. A novel method for elimination of aflatoxin M1 in milk using Lactobacillus rhamnosus GG biofilm. International Journal of Dairy Technology 2019, 72, 248 -256.

AMA Style

Jean Claude Assaf, Andre EL Khoury, Ali Chokr, Nicolas Louka, Ali Atoui. A novel method for elimination of aflatoxin M1 in milk using Lactobacillus rhamnosus GG biofilm. International Journal of Dairy Technology. 2019; 72 (2):248-256.

Chicago/Turabian Style

Jean Claude Assaf; Andre EL Khoury; Ali Chokr; Nicolas Louka; Ali Atoui. 2019. "A novel method for elimination of aflatoxin M1 in milk using Lactobacillus rhamnosus GG biofilm." International Journal of Dairy Technology 72, no. 2: 248-256.

Methods and protocols
Published: 02 June 2018 in Applied Microbiology and Biotechnology
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This study aimed to investigate the ability of chitin and heat-treated shrimp shells to bind aflatoxin M1 (AFM1) in liquid matrix. Several concentrations of chitin or shrimp shells (grinded and ungrinded) were incubated in AFM1-contaminated phosphate-buffered saline (PBS) at different incubation times. The stability of the formed adsorbent-AFM1 complex was also tested in milk at different incubation times and temperatures. The unbound AFM1 was quantified by HPLC. Thereby, the percentages of the initial bounded AFM1 varied between 14.29 and 94.74%. Interestingly, in milk, an increase in incubation time coupled with a decrease in temperature affected positively the amount of bounded AFM1 to chitin and negatively those bounded to ungrinded shells. Results also revealed a partial reversibility in the binding of AFM1 to these adsorbents. These findings provided strong evidence on ability of chitin or shrimp shells by-product to bind AFM1 in milk and in PBS.

ACS Style

Jean Claude Assaf; André El Khoury; Ali Atoui; Nicolas Louka; Ali Chokr. A novel technique for aflatoxin M1 detoxification using chitin or treated shrimp shells: in vitro effect of physical and kinetic parameters on the binding stability. Applied Microbiology and Biotechnology 2018, 102, 6687 -6697.

AMA Style

Jean Claude Assaf, André El Khoury, Ali Atoui, Nicolas Louka, Ali Chokr. A novel technique for aflatoxin M1 detoxification using chitin or treated shrimp shells: in vitro effect of physical and kinetic parameters on the binding stability. Applied Microbiology and Biotechnology. 2018; 102 (15):6687-6697.

Chicago/Turabian Style

Jean Claude Assaf; André El Khoury; Ali Atoui; Nicolas Louka; Ali Chokr. 2018. "A novel technique for aflatoxin M1 detoxification using chitin or treated shrimp shells: in vitro effect of physical and kinetic parameters on the binding stability." Applied Microbiology and Biotechnology 102, no. 15: 6687-6697.

Comparative study
Published: 06 August 2017 in Brazilian Journal of Microbiology
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Several strains of lactic acid bacteria (LAB), frequently used in food fermentation and preservation, have been reported to bind different types of toxins in liquid media. This study was carried out to investigate the effect of different concentrations of Lactobacillus rhamnosus GG (ATCC 53103) to bind aflatoxin M1 (AFM1) in liquid media. AFM1 binding was tested following repetitive washes or filtration procedures in combination with additional treatments such as heating, pipetting, and centrifugation. The mixture of L. rhamnosus GG and AFM1 was incubated for 18 h at 37 °C and the binding efficiency was determined by quantifying the unbound AFM1 using HPLC. The stability of the complexes viable bacteria-AFM1 and heat treated bacteria-AFM1 was tested. Depending on the bacterial concentration and procedure used, the percentages of bound AFM1 by L. rhamnosus GG varied from as low as undetectable to as high as 63%. The highest reduction in the level of unbound AFM1 was recorded for the five washes procedure that involved heating and pipetting. Results also showed that binding was partially reversible and AFM1 was released after repeated washes. These findings highlight the effect of different treatments on the binding of AFM1 to L. rhamnosus GG in liquid matrix.

ACS Style

Jean Claude Assaf; Ali Atoui; André El Khoury; Ali Chokr; Nicolas Louka. A comparative study of procedures for binding of aflatoxin M1 to Lactobacillus rhamnosus GG. Brazilian Journal of Microbiology 2017, 49, 120 -127.

AMA Style

Jean Claude Assaf, Ali Atoui, André El Khoury, Ali Chokr, Nicolas Louka. A comparative study of procedures for binding of aflatoxin M1 to Lactobacillus rhamnosus GG. Brazilian Journal of Microbiology. 2017; 49 (1):120-127.

Chicago/Turabian Style

Jean Claude Assaf; Ali Atoui; André El Khoury; Ali Chokr; Nicolas Louka. 2017. "A comparative study of procedures for binding of aflatoxin M1 to Lactobacillus rhamnosus GG." Brazilian Journal of Microbiology 49, no. 1: 120-127.

Research article
Published: 18 July 2017 in Environmental Science and Pollution Research
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Many freshwater bodies worldwide that suffer from harmful algal blooms would benefit for their management from a simple ecological model that requires few field data, e.g. for early warning systems. Beyond a certain degree, adding processes to ecological models can reduce model predictive capabilities. In this work, we assess whether a simple ecological model without nutrients is able to describe the succession of cyanobacterial blooms of different species in a hypereutrophic reservoir and help understand the factors that determine these blooms. In our study site, Karaoun Reservoir, Lebanon, cyanobacteria Aphanizomenon ovalisporum and Microcystis aeruginosa alternatively bloom. A simple configuration of the model DYRESM-CAEDYM was used; both cyanobacteria were simulated, with constant vertical migration velocity for A. ovalisporum, with vertical migration velocity dependent on light for M. aeruginosa and with growth limited by light and temperature and not by nutrients for both species. The model was calibrated on two successive years with contrasted bloom patterns and high variations in water level. It was able to reproduce the measurements; it showed a good performance for the water level (root-mean-square error (RMSE) lower than 1 m, annual variation of 25 m), water temperature profiles (RMSE of 0.22–1.41 °C, range 13–28 °C) and cyanobacteria biomass (RMSE of 1–57 μg Chl a L−1, range 0–206 μg Chl a L−1). The model also helped understand the succession of blooms in both years. The model results suggest that the higher growth rate of M. aeruginosa during favourable temperature and light conditions allowed it to outgrow A. ovalisporum. Our results show that simple model configurations can be sufficient not only for theoretical works when few major processes can be identified but also for operational applications. This approach could be transposed on other hypereutrophic lakes and reservoirs to describe the competition between dominant phytoplankton species, contribute to early warning systems or be used for management scenarios.

ACS Style

Ali Fadel; Bruno J. Lemaire; Brigitte Vinçon-Leite; Ali Atoui; Kamal Slim; Bruno Tassin. On the successful use of a simplified model to simulate the succession of toxic cyanobacteria in a hypereutrophic reservoir with a highly fluctuating water level. Environmental Science and Pollution Research 2017, 24, 20934 -20948.

AMA Style

Ali Fadel, Bruno J. Lemaire, Brigitte Vinçon-Leite, Ali Atoui, Kamal Slim, Bruno Tassin. On the successful use of a simplified model to simulate the succession of toxic cyanobacteria in a hypereutrophic reservoir with a highly fluctuating water level. Environmental Science and Pollution Research. 2017; 24 (26):20934-20948.

Chicago/Turabian Style

Ali Fadel; Bruno J. Lemaire; Brigitte Vinçon-Leite; Ali Atoui; Kamal Slim; Bruno Tassin. 2017. "On the successful use of a simplified model to simulate the succession of toxic cyanobacteria in a hypereutrophic reservoir with a highly fluctuating water level." Environmental Science and Pollution Research 24, no. 26: 20934-20948.

Journal article
Published: 14 July 2017 in Toxins
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Ochratoxin A (OTA) is one of the most important mycotoxins, and contaminates several agricultural products, particularly cereals, grapes, maize, barley, spices and coffee. The aim of this project was to reduce the levels of OTA by supplementing the artificially contaminated solutions with seven strains of actinobacteria (AT10, AT8, SN7, MS1, ML5, G10 and PT1) in order to evaluate their capacity for binding and metabolizing the OTA, as well as their ability to reduce the expression of the genes responsible for its production in A. carbonarius. In the first part of this study, we evaluated the capacity of Streptomyces strains for binding OTA on their surfaces after 0, 30 and 60 min of incubation with PBS solution supplemented with OTA. In the second part, we tested the ability of these strains, as well as their supernatants, to detoxify the ISP2 medium. Finally, we studied the effect of the Streptomyces cocultured with Aspergillus carbonarius on the expression of OTA biosynthesis genes. Results showed that, among the strains co-cultured with A. carbonarius, the strain G10 was able to reduce the expression of acpks, acOTApks, acOTAnrps and vea genes, thus reducing OTA from solid PDA medium to 13.50% of reduction. This strain was remarkably able to detoxify and bind OTA up to 47.07%. Strain AT8 was stronger in detoxifying OTA (52.61%), but had no significant effect on the studied gene expression.

ACS Style

Rachelle El Khoury; Florence Mathieu; Ali Atoui; Hiba Kawtharani; Anthony El Khoury; Charbel Afif; Richard G. Maroun; André El Khoury. Ability of Soil Isolated Actinobacterial Strains to Prevent, Bind and Biodegrade Ochratoxin A. Toxins 2017, 9, 222 .

AMA Style

Rachelle El Khoury, Florence Mathieu, Ali Atoui, Hiba Kawtharani, Anthony El Khoury, Charbel Afif, Richard G. Maroun, André El Khoury. Ability of Soil Isolated Actinobacterial Strains to Prevent, Bind and Biodegrade Ochratoxin A. Toxins. 2017; 9 (7):222.

Chicago/Turabian Style

Rachelle El Khoury; Florence Mathieu; Ali Atoui; Hiba Kawtharani; Anthony El Khoury; Charbel Afif; Richard G. Maroun; André El Khoury. 2017. "Ability of Soil Isolated Actinobacterial Strains to Prevent, Bind and Biodegrade Ochratoxin A." Toxins 9, no. 7: 222.

Journal article
Published: 09 July 2017 in Antioxidants
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This study is intended to prevent ochratoxin A (OTA) production by Aspergillus carbonarius S402 using essential oils (EOs) and total phenolic compounds extracted from plants and herbs. The EOs used in this study are the following: bay leaves, cumin, fenugreek, melissa, mint, and sage. As for the phenolic compounds, they were extracted from bay leaves, cumin, fenugreek, melissa, mint, sage, anise, chamomile, fennel, rosemary, and thyme. The experiments were conducted on Synthetic Grape Medium (SGM) medium at 28 °C for 4 days. OTA was extracted from the medium with methanol and quantified using HPLC (High Performance Liquid Chromatography). Results showed that EOs had a greater impact than the total phenolic extracts on the OTA production. Reduction levels ranged between 25% (sage) and 80% (melissa) for the EOs at 5 µL mL−1, and 13% (thyme) and 69% (mint) for the phenolic extracts. Although they did not affect the growth of A. carbonarius, total phenolic extracts and EOs were capable of partially reducing OTA production. Reduction levels depended on the nature of the plants and the concentration of the EOs. Reducing OTA with natural extracts could be a solution to prevent OTA production without altering the fungal growth, thus preserving the natural microbial balance.

ACS Style

Rachelle El Khoury; Ali Atoui; Florence Mathieu; Hiba Kawtharani; Anthony El Khoury; Richard G. Maroun; Andre El Khoury. Antifungal and Antiochratoxigenic Activities of Essential Oils and Total Phenolic Extracts: A Comparative Study. Antioxidants 2017, 6, 44 .

AMA Style

Rachelle El Khoury, Ali Atoui, Florence Mathieu, Hiba Kawtharani, Anthony El Khoury, Richard G. Maroun, Andre El Khoury. Antifungal and Antiochratoxigenic Activities of Essential Oils and Total Phenolic Extracts: A Comparative Study. Antioxidants. 2017; 6 (3):44.

Chicago/Turabian Style

Rachelle El Khoury; Ali Atoui; Florence Mathieu; Hiba Kawtharani; Anthony El Khoury; Richard G. Maroun; Andre El Khoury. 2017. "Antifungal and Antiochratoxigenic Activities of Essential Oils and Total Phenolic Extracts: A Comparative Study." Antioxidants 6, no. 3: 44.

Review
Published: 02 June 2017 in Critical Reviews in Food Science and Nutrition
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The plant pathogenic fungus Penicillium expansum is a major concern of the global food industry due to its wide occurrence and ability to produce various mycotoxins, of which the most significant is patulin. Relatively less highlighted in the literature, in comparison with the other food-borne mycotoxins, patulin is one of the main factors in economic losses of vegetables and fruits. Otherwise, patulin is a health hazard which results in both short-term and long-term risks. This review includes knowledge on the biosynthetic mechanisms used for secondary metabolite production in P. expansum, with special emphasis on patulin biosynthesis. The abiotic factors triggering the production of patulin and the strategies developed to reduce or prevent the contamination by this mycotoxin are comprehensively discussed. The database presented in this review would be useful for the prioritization and development of future research

ACS Style

Joanna Tannous; Nancy P. Keller; Ali Atoui; Andre EL Khoury; Roger Lteif; Isabelle Oswald; Olivier Puel. Secondary metabolism in Penicillium expansum: Emphasis on recent advances in patulin research. Critical Reviews in Food Science and Nutrition 2017, 58, 2082 -2098.

AMA Style

Joanna Tannous, Nancy P. Keller, Ali Atoui, Andre EL Khoury, Roger Lteif, Isabelle Oswald, Olivier Puel. Secondary metabolism in Penicillium expansum: Emphasis on recent advances in patulin research. Critical Reviews in Food Science and Nutrition. 2017; 58 (12):2082-2098.

Chicago/Turabian Style

Joanna Tannous; Nancy P. Keller; Ali Atoui; Andre EL Khoury; Roger Lteif; Isabelle Oswald; Olivier Puel. 2017. "Secondary metabolism in Penicillium expansum: Emphasis on recent advances in patulin research." Critical Reviews in Food Science and Nutrition 58, no. 12: 2082-2098.

Journal article
Published: 01 March 2017 in Toxins
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Of all the food-contaminating mycotoxins, aflatoxins, and most notably aflatoxin B1 (AFB1), are found to be the most toxic and economically costly. Green farming is striving to replace fungicides and develop natural preventive strategies to minimize crop contamination by these toxic fungal metabolites. In this study, we demonstrated that an aqueous extract of the medicinal plant Micromeria graeca—known as hyssop—completely inhibits aflatoxin production by Aspergillus flavus without reducing fungal growth. The molecular inhibitory mechanism was explored by analyzing the expression of 61 genes, including 27 aflatoxin biosynthesis cluster genes and 34 secondary metabolism regulatory genes. This analysis revealed a three-fold down-regulation of aflR and aflS encoding the two internal cluster co-activators, resulting in a drastic repression of all aflatoxin biosynthesis genes. Hyssop also targeted fifteen regulatory genes, including veA and mtfA, two major global-regulating transcription factors. The effect of this extract is also linked to a transcriptomic variation of several genes required for the response to oxidative stress such as msnA, srrA, catA, cat2, sod1, mnsod, and stuA. In conclusion, hyssop inhibits AFB1 synthesis at the transcriptomic level. This aqueous extract is a promising natural-based solution to control AFB1 contamination.

ACS Style

Rhoda El Khoury; Isaura Caceres; Olivier Puel; Sylviane Bailly; Ali Atoui; Isabelle P. Oswald; André El Khoury; Jean-Denis Bailly. Identification of the Anti-Aflatoxinogenic Activity of Micromeria graeca and Elucidation of Its Molecular Mechanism in Aspergillus flavus. Toxins 2017, 9, 87 .

AMA Style

Rhoda El Khoury, Isaura Caceres, Olivier Puel, Sylviane Bailly, Ali Atoui, Isabelle P. Oswald, André El Khoury, Jean-Denis Bailly. Identification of the Anti-Aflatoxinogenic Activity of Micromeria graeca and Elucidation of Its Molecular Mechanism in Aspergillus flavus. Toxins. 2017; 9 (3):87.

Chicago/Turabian Style

Rhoda El Khoury; Isaura Caceres; Olivier Puel; Sylviane Bailly; Ali Atoui; Isabelle P. Oswald; André El Khoury; Jean-Denis Bailly. 2017. "Identification of the Anti-Aflatoxinogenic Activity of Micromeria graeca and Elucidation of Its Molecular Mechanism in Aspergillus flavus." Toxins 9, no. 3: 87.

Book chapter
Published: 07 December 2016 in Advanced Structural Safety Studies
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Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) is the most simple method for single-nucleotide change detection. It is widely used in the detection and differentiation between mycotoxigenic species. It is based on PCR amplification of a target region containing the variant site of the studied species followed by restriction endonuclease digestion and gel electrophoresis to visualize the RFLP patterns. In this method primers are designed to flank the polymorphic site and positioned in such a way as to create unequally sized fragments upon restriction endonuclease cleavage of the PCR products. Here, we describe the protocol of PCR-RFLP developed for the detection and differentiation between Aspergillus flavus and A. parasiticus by amplifying a 674 bp fragment of the aflR-aflJ intergenic region followed by restriction endonuclease analysis using BglII to obtain RFLP patterns.

ACS Style

Ali Atoui; André El Khoury. PCR-RFLP for Aspergillus Species. Advanced Structural Safety Studies 2016, 1542, 313 -320.

AMA Style

Ali Atoui, André El Khoury. PCR-RFLP for Aspergillus Species. Advanced Structural Safety Studies. 2016; 1542 ():313-320.

Chicago/Turabian Style

Ali Atoui; André El Khoury. 2016. "PCR-RFLP for Aspergillus Species." Advanced Structural Safety Studies 1542, no. : 313-320.

Biologics
Published: 02 December 2016 in Archives of Toxicology
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Patulin is the main mycotoxin contaminating apples. During the brewing of alcoholic beverages, this mycotoxin is degraded to ascladiol, which is also the last precursor of patulin. The present study aims (1) to characterize the last step of the patulin biosynthetic pathway and (2) to describe the toxicity of ascladiol. A patE deletion mutant was generated in Penicillium expansum. In contrast to the wild strain, this mutant does not produce patulin but accumulates high levels of E-ascladiol with few traces of Z-ascladiol. This confirms that patE encodes the patulin synthase involved in the conversion of E-ascladiol to patulin. After purification, cytotoxicities of patulin and E- and Z-ascladiol were investigated on human cell lines from liver, kidney, intestine, and immune system. Patulin was cytotoxic for these four cell lines in a dose-dependent manner. By contrast, both E- and Z-ascladiol were devoid of cytotoxicity. Microarray analyses on human intestinal cells treated with patulin and E-ascladiol showed that the latter, unlike patulin, did not alter the whole human transcription. These results demonstrate that E- and Z-ascladiol are not toxic and therefore patulin detoxification strategies leading to the accumulation of ascladiol are good approaches to limit the patulin risk

ACS Style

Joanna Tannous; Selma Snini; Rhoda El Khoury; Cécile Canlet; Philippe Pinton; Yannick Lippi; Imourana Alassane-Kpembi; Thierry Gauthier; Andre EL Khoury; Ali Atoui; Ting Zhou; Roger Lteif; Isabelle Oswald; Olivier Puel. Patulin transformation products and last intermediates in its biosynthetic pathway, E- and Z-ascladiol, are not toxic to human cells. Archives of Toxicology 2016, 91, 2455 -2467.

AMA Style

Joanna Tannous, Selma Snini, Rhoda El Khoury, Cécile Canlet, Philippe Pinton, Yannick Lippi, Imourana Alassane-Kpembi, Thierry Gauthier, Andre EL Khoury, Ali Atoui, Ting Zhou, Roger Lteif, Isabelle Oswald, Olivier Puel. Patulin transformation products and last intermediates in its biosynthetic pathway, E- and Z-ascladiol, are not toxic to human cells. Archives of Toxicology. 2016; 91 (6):2455-2467.

Chicago/Turabian Style

Joanna Tannous; Selma Snini; Rhoda El Khoury; Cécile Canlet; Philippe Pinton; Yannick Lippi; Imourana Alassane-Kpembi; Thierry Gauthier; Andre EL Khoury; Ali Atoui; Ting Zhou; Roger Lteif; Isabelle Oswald; Olivier Puel. 2016. "Patulin transformation products and last intermediates in its biosynthetic pathway, E- and Z-ascladiol, are not toxic to human cells." Archives of Toxicology 91, no. 6: 2455-2467.

Comparative study
Published: 19 August 2016 in Toxins
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Ochratoxin A (OTA) is a mycotoxin, mainly produced on grapes by Aspergillus carbonarius, that causes massive health problems for humans. This study aims to reduce the occurrence of OTA by using the ten following essential oils (E.Os): fennel, cardamom, anise, chamomile, celery, cinnamon, thyme, taramira, oregano and rosemary at 1 µL/mL and 5 µL/mL for each E.O.As a matter of fact, their effects on the OTA production and the growth of A. carbonarius S402 cultures were evaluated, after four days at 28 °C on a Synthetic Grape Medium (SGM). Results showed that A. carbonarius growth was reduced up to 100%, when cultured with the E.Os of cinnamon, taramira, and oregano at both concentrations and the thyme at 5 µL/mL. As for the other six E.Os, their effect on A. carbonarius growth was insignificant, but highly important on the OTA production. Interestingly, the fennel E.O at 5 µL/mL reduced the OTA production up to 88.9% compared to the control, with only 13.8% of fungal growth reduction. We further investigated the effect of these E.Os on the expression levels of the genes responsible for the OTA biosynthesis (acOTApks and acOTAnrps along with the acpks gene) as well as the two regulatory genes laeA and vea, using the quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) method. The results revealed that these six E.Os reduced the expression of the five studied genes, where the ackps was downregulated by 99.2% (the highest downregulation in this study) with 5 µL/mL of fennel E.O.As for the acOTApks, acOTAnrps, veA and laeA, their reduction levels ranged between 10% and 96% depending on the nature of the E.O and its concentration in the medium.

ACS Style

Rachelle El Khoury; Ali Atoui; Carol Verheecke; Richard Maroun; Andre El Khoury; Florence Mathieu. Essential Oils Modulate Gene Expression and Ochratoxin A Production in Aspergillus carbonarius. Toxins 2016, 8, 242 .

AMA Style

Rachelle El Khoury, Ali Atoui, Carol Verheecke, Richard Maroun, Andre El Khoury, Florence Mathieu. Essential Oils Modulate Gene Expression and Ochratoxin A Production in Aspergillus carbonarius. Toxins. 2016; 8 (8):242.

Chicago/Turabian Style

Rachelle El Khoury; Ali Atoui; Carol Verheecke; Richard Maroun; Andre El Khoury; Florence Mathieu. 2016. "Essential Oils Modulate Gene Expression and Ochratoxin A Production in Aspergillus carbonarius." Toxins 8, no. 8: 242.

Journal article
Published: 26 April 2016 in Toxins
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Produced by several species of Aspergillus, Aflatoxin B1 (AFB1) is a carcinogenic mycotoxin contaminating many crops worldwide. The utilization of fungicides is currently one of the most common methods; nevertheless, their use is not environmentally or economically sound. Thus, the use of natural compounds able to block aflatoxinogenesis could represent an alternative strategy to limit food and feed contamination. For instance, eugenol, a 4-allyl-2-methoxyphenol present in many essential oils, has been identified as an anti-aflatoxin molecule. However, its precise mechanism of action has yet to be clarified. The production of AFB1 is associated with the expression of a 70 kB cluster, and not less than 21 enzymatic reactions are necessary for its production. Based on former empirical data, a molecular tool composed of 60 genes targeting 27 genes of aflatoxin B1 cluster and 33 genes encoding the main regulatory factors potentially involved in its production, was developed. We showed that AFB1 inhibition in Aspergillus flavus following eugenol addition at 0.5 mM in a Malt Extract Agar (MEA) medium resulted in a complete inhibition of the expression of all but one gene of the AFB1 biosynthesis cluster. This transcriptomic effect followed a down-regulation of the complex composed by the two internal regulatory factors, AflR and AflS. This phenomenon was also influenced by an over-expression of veA and mtfA, two genes that are directly linked to AFB1 cluster regulation.

ACS Style

Isaura Caceres; Rhoda El Khoury; Ángel Medina; Yannick Lippi; Claire Naylies; Ali Atoui; André El Khoury; Isabelle P. Oswald; Jean-Denis Bailly; Olivier Puel. Deciphering the Anti-Aflatoxinogenic Properties of Eugenol Using a Large-Scale q-PCR Approach. Toxins 2016, 8, 123 .

AMA Style

Isaura Caceres, Rhoda El Khoury, Ángel Medina, Yannick Lippi, Claire Naylies, Ali Atoui, André El Khoury, Isabelle P. Oswald, Jean-Denis Bailly, Olivier Puel. Deciphering the Anti-Aflatoxinogenic Properties of Eugenol Using a Large-Scale q-PCR Approach. Toxins. 2016; 8 (5):123.

Chicago/Turabian Style

Isaura Caceres; Rhoda El Khoury; Ángel Medina; Yannick Lippi; Claire Naylies; Ali Atoui; André El Khoury; Isabelle P. Oswald; Jean-Denis Bailly; Olivier Puel. 2016. "Deciphering the Anti-Aflatoxinogenic Properties of Eugenol Using a Large-Scale q-PCR Approach." Toxins 8, no. 5: 123.

Journal article
Published: 16 December 2015 in Food Science & Nutrition
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Penicillium expansum is among the most ubiquitous fungi disseminated worldwide, that could threaten the fruit sector by secreting patulin, a toxic secondary metabolite. Nevertheless, we lack sufficient data regarding the growth and the toxigenesis conditions of this species. This work enables a clear differentiation between the favorable conditions to the P. expansum growth and those promising for patulin production. A mathematical model allowing the estimation of the P. expansum growth rate according to temperature, aW, and pH, was also developed. An optimal growth rate of 0.92 cm/day was predicted at 24°C with pH level of 5.1 and high aW level of 0.99. The model's predictive capability was tested successfully on artificial contaminated apples. This model could be exploited by apple growers and the industrialists of fruit juices in order to predict the development of P. expansum during storage and apple processing.

ACS Style

Joanna Tannous; Ali Atoui; Andre EL Khoury; Ziad Francis; Isabelle Oswald; Olivier Puel; Roger Lteif. A study on the physicochemical parameters for P enicillium expansum growth and patulin production: effect of temperature, pH, and water activity. Food Science & Nutrition 2015, 4, 611 -622.

AMA Style

Joanna Tannous, Ali Atoui, Andre EL Khoury, Ziad Francis, Isabelle Oswald, Olivier Puel, Roger Lteif. A study on the physicochemical parameters for P enicillium expansum growth and patulin production: effect of temperature, pH, and water activity. Food Science & Nutrition. 2015; 4 (4):611-622.

Chicago/Turabian Style

Joanna Tannous; Ali Atoui; Andre EL Khoury; Ziad Francis; Isabelle Oswald; Olivier Puel; Roger Lteif. 2015. "A study on the physicochemical parameters for P enicillium expansum growth and patulin production: effect of temperature, pH, and water activity." Food Science & Nutrition 4, no. 4: 611-622.

Journal article
Published: 18 September 2015 in Environmental Monitoring and Assessment
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Eutrophication and harmful algal blooms have become a worldwide environmental problem. Understanding the mechanisms and processes that control algal blooms is of great concern. The phytoplankton community of Karaoun Reservoir, the largest water body in Lebanon, is poorly studied, as in many freshwater bodies around the Mediterranean Sea. Sampling campaigns were conducted semi-monthly between May 2012 and August 2013 to assess the dynamics of its phytoplankton community in response to changes in physical-chemical and hydrological conditions. Karaoun Reservoir is a monomictic waterbody and strongly stratifies between May and August. Changes in its phytoplankton community were found to be a result of the interplay between water temperature, stratification, irradiance, nutrient availability and water level. Thermal stratification established in spring reduced the growth of diatoms and resulted in their replacement by green algae species when nutrient availability was high and water temperatures lower than 22 °C. At water temperature higher than 25 °C and low nutrient concentrations in summer, blooms of the cyanobacterium Microcystis aeruginosa occurred. Despite different growth conditions in other lakes and reservoir, cyanobacterium Aphanizomenon ovalisporum dominated at temperatures lower than 23 °C in weakly stratified conditions in early autumn and dinoflagellate Ceratium hirundinella dominated in mixed conditions, at low light intensity and a water temperature of 19 °C in late autumn. We believe that the information presented in this paper will increase the knowledge about phytoplankton dynamics in the Mediterranean region and contribute to a safer usage of reservoir waters.

ACS Style

Ali Fadel; Ali Atoui; Bruno J. Lemaire; Brigitte Vinçon-Leite; Kamal Slim. Environmental factors associated with phytoplankton succession in a Mediterranean reservoir with a highly fluctuating water level. Environmental Monitoring and Assessment 2015, 187, 1 -14.

AMA Style

Ali Fadel, Ali Atoui, Bruno J. Lemaire, Brigitte Vinçon-Leite, Kamal Slim. Environmental factors associated with phytoplankton succession in a Mediterranean reservoir with a highly fluctuating water level. Environmental Monitoring and Assessment. 2015; 187 (10):1-14.

Chicago/Turabian Style

Ali Fadel; Ali Atoui; Bruno J. Lemaire; Brigitte Vinçon-Leite; Kamal Slim. 2015. "Environmental factors associated with phytoplankton succession in a Mediterranean reservoir with a highly fluctuating water level." Environmental Monitoring and Assessment 187, no. 10: 1-14.

Journal article
Published: 01 September 2015 in Food Microbiology
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Due to the occurrence and spread of the fungal contaminants in food and the difficulties to remove their resulting mycotoxins, rapid and accurate methods are needed for early detection of these mycotoxigenic fungi. The polymerase chain reaction and the real time PCR have been widely used for this purpose. Apples are suitable substrates for fungal colonization mostly caused by Penicillium expansum, which produces the mycotoxin patulin during fruit infection. This study describes the development of a real-time PCR assay incorporating an internal amplification control (IAC) to specifically detect and quantify P. expansum. A specific primer pair was designed from the patF gene, involved in patulin biosynthesis. The selected primer set showed a high specificity for P. expansum and was successfully employed in a standardized real-time PCR for the direct quantification of this fungus in apples. Using the developed system, twenty eight apples were analyzed for their DNA content. Apples were also analyzed for patulin content by HPLC. Interestingly, a positive correlation (R(2) = 0.701) was found between P. expansum DNA content and patulin concentration. This work offers an alternative to conventional methods of patulin quantification and mycological detection of P. expansum and could be very useful for the screening of patulin in fruits through the application of industrial quality control.

ACS Style

Joanna Tannous; Ali Atoui; Andre EL Khoury; Sally Kantar; Nader Chdid; Isabelle Oswald; Olivier Puel; Roger Lteif. Development of a real-time PCR assay for Penicillium expansum quantification and patulin estimation in apples. Food Microbiology 2015, 50, 28 -37.

AMA Style

Joanna Tannous, Ali Atoui, Andre EL Khoury, Sally Kantar, Nader Chdid, Isabelle Oswald, Olivier Puel, Roger Lteif. Development of a real-time PCR assay for Penicillium expansum quantification and patulin estimation in apples. Food Microbiology. 2015; 50 ():28-37.

Chicago/Turabian Style

Joanna Tannous; Ali Atoui; Andre EL Khoury; Sally Kantar; Nader Chdid; Isabelle Oswald; Olivier Puel; Roger Lteif. 2015. "Development of a real-time PCR assay for Penicillium expansum quantification and patulin estimation in apples." Food Microbiology 50, no. : 28-37.