Long-term testing of patulin administered orally to Sprague-Dawley rats and Swiss mice

Natural Thiols, but Not Thioethers, Attenuate Patulin-Induced Endoplasmic Reticulum Stress in HepG2 Cells

Patulin, a mycotoxin, is known to have cytotoxic effects, but few studies have focused on the involvement of the endoplasmic reticulum (ER) stress response in patulin toxicity and the natural compounds that attenuate it in HepG2 cells. This study tested the ability of patulin to induce ER stress, and that of four thiols and three thioethers to attenuate patulin-induced ER stress in HepG2 cells. Patulin dose-dependently inhibited cell proliferation (IC₅₀, 8.43 μM). Additionally, patulin was found to increase the expression levels of ER stress-related genes and/or protein markers, including BiP, CHOP, and spliced XBP1, in HepG2 cells compared to the vehicle control, indicating its potential in ER stress induction. Patulin-induced cytotoxicity in HepG2 cells was reduced by naturally occurring thiol compounds (glutathione, L-acetyl-L-cysteine, cysteine, and captopril), but not by thioether compounds (sulforaphane, sulforaphene, and S-allyl-L-cysteine). Patulin-thiol co-treatment decreased CHOP expression and BiP and CHOP levels in HepG2 cells but did not alter BiP expression. Spliced XBP1 expression was decreased by patulin-thiol co-treatment. Thus, patulin induced ER stress in HepG2 cells and thiols, but not in thioethers, attenuated patulin-induced ER stress.

The characteristics, occurrence, and toxicological effects of patulin

Mycotoxins are the secondary metabolites secreted by different types of fungi to which humans can get exposed mainly via ingestion. Patulin (C₇H₆O₄) is a polyketide lactone produced by various fungal specifies, including Penicillium expansum as the main producer. P. expansum can infect different fruits and vegetables yet it has preference to apples in which they cause blue rot. Therefore, apples and apple-based food products are the main source of Patulin exposure for humans. Patulin was first identified in 1943 under the name of tercinin as a possible antimicrobial agent. Although it is categorized as a non-carcinogen, Patulin has been linked, in the last decades, to neurological, gastrointestinal, and immunological adverse effects, mainly causing liver and kidney damages. In this review, the characteristics of and possible human exposure pathways to Patulin are discussed. Various surveillance and toxicity studies on the levels of Patulin in various food products and effects of Patulin on cells and animal models have been documented as well. Importance of epidemiological studies and a summary of the possible toxicity mechanisms are highlighted with a case study. The commonly used control methods as described in the literature are also discussed to guide future researchers to focus on mitigating mycotoxins contamination in the food industry.

Mycotoxin patulin in food matrices: occurrence and its biological degradation strategies

Patulin is a mycotoxin produced by a number of filamentous fungal species. It is a polyketide secondary metabolite which can gravely cause human health problems and food safety issues. This review deals with the occurrence of patulin in major food commodities from 2008 to date, including historical aspects, source, occurrence, regulatory limits and its toxicity. Most importantly, an overview of the recent research progress about the biodegradation strategies for contaminated food matrices is provided. The physical and chemical approaches have some drawbacks such as safety issues, possible losses in the nutritional quality, chemical hazards, limited efficacy, and high cost. The biological decontamination based on elimination or degradation of patulin using yeast, bacteria, and fungi has shown good results and it seems to be attractive since it works under mild and environment-friendly conditions. Further studies are needed to make clear the detoxification pathways by available potential biosorbents and to determine the practical applications of these methods at a commercial level to remove patulin from food products with special reference to their effects on sensory characteristics of foods.

Low dose exposure of patulin and protective effect of epicatechin on blood cells in vitro

In the present study, we aimed to assess antioxidant status in erythrocytes in vitro after patulin (PAT) and epicatechin exposure by measuring antioxidant enzymes (superoxide-dismutase - SOD, glutathione peroxidase - GPx and catalase - CAT) and parameters associated with oxidative stress (malondialdehyde - MDA and ROS). We also investigated the effect of PAT on viability and count of lymphocytes and lymphocyte subpopulations in rabbit blood in vitro. Whole blood of rabbits was used for analysis of antioxidant changes in rabbit erythrocytes after epicatechin and PAT treatment (separately or in combination, at concentrations of 0.2; 2; 20; 200 µg mL^-1 of epicatechin and 0.5; 5; 10 µg mL^-1 of PAT). Whole blood of rabbits was also used for analysis of count and viability of lymphocytes after PAT treatment at concentrations of 10; 25 and 50 µg mL^-1. Results from our experiment confirmed the ability of epicatechin to protect cells against oxidative stress and lipoperoxidation. Our findings indicate that mycotoxin PAT in low concentrations did not affect the activity of antioxidant enzymes in erythrocytes of rabbits significantly. Only slight non-significant changes in lymphocytes count after treatment with low doses of PAT in rabbit blood were observed.

Crosstalk between proteins expression and lysine acetylation in response to patulin stress in Rhodotorula mucilaginosa

The proteomic and lysine acetylation (Kac) changes, accompanying degradation of patulin in Rhodotorula mucilaginosa were analyzed using tandem mass tagging and N6-acetyllysine affinity enrichment followed by LC-MS/MS. Proteomic results showed that expression level of short-chain reductase protein and glutathione S-transferase involved in detoxification was significantly up-regulated. In addition, the expression levels of zinc-binding oxidoreductase and quinone oxidoreductase that are involved in antioxidant process, ABC transport and MFS transport responsible for chemical transport were activated when treated with patulin. The quantitative real time PCR (qRT-PCR) result also indicated these genes expression levels were increased when treated with patulin. Kac changes accompanying degradation of patulin in R. mucilaginosa were also observed. Totally, 130 Kac sites in 103 proteins were differentially expressed under patulin stress. The differentially up expressed modified proteins were mainly involved in tricarboxylic acid cycle and nuclear acid biosynthesis. The differentially down expressed Kac proteins were mainly classified to ribosome, oxidative phosphorylation, protein synthesis and defense to stress process. Our results suggest that patulin exposure prompt R. mucilaginosa to produce a series of actions to resist or degrade patulin, including Kac. In addition, the Kac information in R. mucilaginosa and Kac in response to patulin stress was firstly revealed.

Toxicological effects of patulin mycotoxin on the mammalian system: an overview

The mycotoxin PAT (4-hydroxy-4H-furo[3,2c]pyran-2[6H]-one) is a secondary metabolic product of molds such as Penicillium, Aspergillus, and Byssochlamys species. PAT is a common contaminant of fruit and vegetable based products, most notably apples. Despite PAT's original discovery as an antibiotic, it has come under heavy scrutiny for its potential to impart negative health effects. Studies investigating these health effects have proved its toxic potential. PAT occurrence in the food commodities poses a serious threat and necessitates novel and cost-effective mitigation methods to remove it from food products. It also creates a demand to improve handling and food processing techniques. With this being the case, several studies have been devoted to understanding the key biological and chemical attributes of PAT. While past research has elucidated a great deal, PAT contamination continues to be a challenge for the food industry. Here, we review its influence within the mammalian system, including its regulation, incidences of experimental evidence of PAT toxicity, its interaction with intracellular components, and the effects of PAT induced systemic toxicity on vital organs. Finally, key areas where future PAT research should focus to best control the PAT contamination problem within the food industry have been addressed.

Screening of a Combinatorial Library of Organic Polymers for the Solid-Phase Extraction of Patulin from Apple Juice

Patulin is a water-soluble mycotoxin produced by several species of fungi. Governmental bodies have placed it under scrutiny for its potential negative health effects, and maximum residue limits are fixed in specific food matrices to protect consumers’ health. Confirmatory analysis of patulin in complex food matrices can be a difficult task, and sample clean-up treatments are frequently necessary before instrumental analyses. With the aim of simplifying the clean-up step, we prepared a 256-member combinatorial polymeric library based on 16 functional monomers, four cross-linkers and four different porogenic solvents. The library was screened for the binding towards patulin in different media (acetonitrile and citrate buffer at pH 3.2), with the goal of identifying polymer formulations with good binding properties towards the target compound. As a proof of concept, a methacrylic acid-co-pentaerithrytole tetraacrylate polymer prepared in chloroform was successfully used as a solid-phase extraction material for the clean-up and extraction of patulin from apple juice. Clean chromatographic patterns and acceptable recoveries were obtained for juice spiked with patulin at concentration levels of 25 (64 ± 12%), 50 (83 ± 5.6%) and 100 μg L⁻¹ (76 ± 4.5%). The within-day and between-day reproducibility evaluated at a concentration level of 25 μg L⁻¹ were 5.6 and 7.6%, respectively.

Effects of different mycotoxins on humans, cell genome and their involvement in cancer (Review)

The chemical nature of most of the mycotoxins makes them highly liposoluble compounds that can be absorbed from the site of exposure such as from the gastrointestinal and respiratory tract to the blood stream where it can be dissimilated throughout the body and reach different organs such as the liver and kidneys. Mycotoxins have a strong tendency and ability to penetrate the human and animal cells and reach the cellular genome where it causes a major mutagenic change in the nucleotide sequence which leads to strong and permanent defects in the genome. This defect will eventually be transcribed, translated and lead to the development of cancer. In this review, the chemical and physical nature of mycotoxins, the action of mycotoxins on the cellular genome and its effect on humans, mycotoxins and their carcinogenicity and mycotoxins research gaps are discussed, and new research areas are suggested. The research review posed various questions. What are the different mycotoxins that can cause cancer, what is the role of mycotoxins in causing cancer and what types of cancers can be caused by mycotoxins? These questions have been selected due to the significant increase in the mycotoxin contamination and the cancer incidence rate in the contemporary world. By revealing and understanding the role of mycotoxins in developing cancer, measures to reduce the risks and incidents of cancer could be taken.

The Possible Mechanisms Involved in Degradation of Patulin by Pichia caribbica

In this work, we examined the mechanisms involved in the degradation of patulin by Pichia caribbica. Our results indicate that cell-free filtrate of P. caribbica reduced patutlin content. The heat-killed cells could not degrade patulin. However, the live cells significantly reduced the concentration of the patulin. In furtherance to this, it was observed that patulin was not detected in the broken yeast cells and cell wall. The addition of cycloheximide to the P. caribbica cells decreased the capacity of degradation of patulin. Proteomics analyses revealed that patulin treatment resulted in an upregulated protein which was involved in metabolism and stress response processes. Our results suggested that the mechanism of degradation of patulin by P. caribbica was not absorption; the presence of patulin can induce P. caribbica to produce associated intracellular and extracellular enzymes, both of which have the ability to degrade patulin. The result provides a new possible method that used the enzymes produced by yeast to detoxify patulin in food and feed.

Crocin protects the liver and kidney from patulin-induced apoptosis in vivo

Patulin (PAT) is a mycotoxin mainly produced by Aspergillus, Penicillium, and Bissochlamys. Given the high risk associated with this mycotoxin, its potential effects have been investigated by many studies. It is known to be teratogenic, mutagenic, and genotoxic, and it has been shown to induce damages in several organs in experimental animals. Our aim was to investigate the preventive effect against PAT-induced apoptosis in vivo using natural carotenoid, Crocin (CRO). Mice were divided into six groups: a control group, a "PAT alone" group, a "CRO alone" group, and a "PAT plus CRO" groups (pre-treatment conditions). Our results showed that CRO restored the normal levels of biochemical parameters in the liver and kidney. The analysis of the protein expression in these organs revealed that PAT-induced toxicity promotes the induction of apoptosis via the increase in P53, Bax, and cytochrome C and the decrease in Bcl2 expressions. We also found that PAT triggered caspase 3 activation and DNA fragmentation. However, pre-treatment with CRO demonstrated a reduction in the induction of apoptosis via the regulation of all tested biomarkers demonstrating that CRO is effective in the protection against PAT hazards. This could be relevant, particularly with the emergent demand for natural products which may counteract the detrimental toxic effects and therefore prevents multiple human diseases.

Effect of the yeast Rhodosporidium paludigenum on postharvest decay and patulin accumulation in apples and pears

The effect of a strain of marine yeast Rhodosporidium paludigenum on postharvest blue mold and patulin accumulation in apples and pears stored at 23°C was evaluated. The occurrence and severity of apple and pear decay caused by Penicillium expansum were significantly inhibited by R. paludigenum. However, the application of the yeast at a high concentration (10(8) cells per ml) enhanced patulin accumulation after 7 days of storage; the amount of patulin increased 24.2 times and 12.6 times compared to the controls in infected apples and pears, respectively. However, R. paludigenum reduced the patulin concentration in the growth medium by both biological degradation and physical adsorption. Optimal in vitro patulin reduction was observed at 30°C and at pH 6.0. R. paludigenum incubated at 28°C was tolerant to patulin at concentrations up to 100 mg/liter. In conclusion, R. paludigenum was able to control postharvest decay in apples and pears and to remove patulin in vitro effectively. However, because the yeast induced patulin accumulation in fruit, the assessment of mycotoxin content after biological treatments in postharvest decay control is important. R. paludigenum may also be a promising source of gene(s) and enzyme(s) for patulin degradation and may be a tool to decrease patulin contamination in commercial fruit-derived products.

Examination of the taxonomic position of Penicillium strains used in blue cheese production based on the partial sequence of β-tubulin

Penicillium roqueforti is a well known starter used for blue cheese production. Two closely related species, P. carneum and P. paneum, were previously classified as varieties of P. roqueforti. Penicillium roqueforti does not produce patulin, a mycotoxin harmful for human health, whereas both P. carneum and P. paneum actively produce this toxin. From the viewpoint of food safety, it is thus important to confirm that P. carneum and P. paneum are not used for cheese production. In the present study, the taxonomic position of Penicillium strains used for blue cheese production was examined on the basis of the partial sequence of β-tubulin. Twenty-eight Penicillium strains isolated from blue cheeses were investigated. All the examined strains belonged to P. roqueforti. Therefore, the Penicillium strains used for production of the blue cheese samples examined here do not negatively impact on human health.

Mechanisms of Mycotoxin-induced Dermal Toxicity and Tumorigenesis Through Oxidative Stress-related Pathways

Among the many mycotoxins, T-2 toxin, citrinin (CTN), patulin (PAT), aflatoxin B1 (AFB1) and ochratoxin A (OTA) are known to have the potential to induce dermal toxicity and/or tumorigenesis in rodent models. T-2 toxin, CTN, PAT and OTA induce apoptosis in mouse or rat skin. PAT, AFB1 and OTA have tumor initiating properties, and OTA is also a tumor promoter in mouse skin. This paper reviews the molecular mechanisms of dermal toxicity and tumorigenesis induced in rodent models by these mycotoxins especially from the viewpoint of oxidative stress-mediated pathways.

EGFR-mediated Akt and MAPKs signal pathways play a crucial role in patulin-induced cell proliferation in primary murine keratinocytes via modulation of Cyclin D1 and COX-2 expression

Patulin (PAT), a present day major contaminant of commercial apple and apple products is reported to be carcinogenic, embryotoxic, and immunotoxic. While oral and inhalation are considered to be the most prevalent routes of exposure to this toxin, exposure through skin is now being extensively investigated. Our previous study showed that short-term dermal exposure to PAT resulted in toxicological injury to the skin, while long-term exposure induced skin tumorigenesis. In this study, we explore the mechanism involve in proliferation of mouse keratinocytes by PAT. Our study revealed that PAT rapidly induces phosphorylation of EGFR, activation of the Ras/MAPKs, and Akt pathways. This in-turn leads to the activation of NF-κB/AP-1 transcription factors which then binds to the promoter region of the cell growth regulatory genes Cyclin D1 and COX-2 inducing their expression leading ultimately to PMKs proliferation. Inhibition of EGFR or the Ras/MAPKs, PI3/Akt pathways with different pharmacological inhibitors or knockdown of NF-κB, c-jun, c-fos, Cyclin D1, and COX-2 with siRNA inhibited PAT-induced PMKs proliferation.

Antioxidative and antigenotoxic effect of vitamin E against patulin cytotoxicity and genotoxicity in HepG2 cells

Patulin (PAT) is a mycotoxin produced in fruits, mainly in apples, by certain species of Penicillium, Aspergillus, and Byssochlamys. It has been shown that PAT is cytotoxic, genotoxic, and mutagenic in different cell types. Several studies incriminate the oxidative stress as a mechanism of PAT-mediated toxicity. In this context, our aim was to investigate the protective role of Vitamin E (Vit E), an antioxidant agent, against PAT induced cytotoxicity and genotoxicity in cultured HepG2 cells. The obtained results showed that addition of Vit E in cells treated with PAT significantly reduce cell mortality induced by this toxin. In the same conditions, Vit E decreased the intracellular level of ROS, reduced PAT induced p53 expression, and reversed PAT induced DNA damage. In addition, Vit E prevented significantly the percentage of chromosome aberrations induced by PAT in HepG2 cells in a concentration dependant manner. These results suggest that Vit E, an exogenous antioxidant agent, plays an important role in defense against PAT-induced cytotoxicity and genotoxicity, which confirms the involvement of oxidative stress in the induction of DNA damage by PAT in HepG2 cells.

Evaluation of genotoxicity, cytotoxicity and cytostasis in human lymphocytes exposed to patulin by using the cytokinesis-block micronucleus cytome (CBMN cyt) assay

Patulin (PAT) is a fungal secondary metabolite commonly present in apples and apple products. In the present study, PAT was evaluated for its genotoxic, cytotoxic and cytostatic effects to human peripheral blood lymphocytes by using the cytokinesis-block micronucleus cytome (CBMN Cyt) assay. Lymphocyte cultures were treated with PAT at the following concentrations, 0.1, 0.3, 0.5, 1.0, 2.5, 5.0, and 7.5 μM, as well as 0.5 μM mitomycin c (MMC) as a positive control and dimethyl sulfoxide (DMSO) as a vehicle control. PAT was found to induce nucleoplasmic bridges (NPBs) at 5.0 and 7.5 μM concentrations (P < 0.05), apoptotic cells at 0.1, 1.0, 5.0 μM (P < 0.05), 7.5 μM concentrations (P < 0.01) and necrotic cells at 0.3 and 2.5 μM (P < 0.05), 5.0 and 7.5 μM (P < 0.01) concentrations in human lymphocytes. The 2.5, 5.0, and 7.5 μM PAT concentrations also led to a clear decrease in the nuclear division index (NDI) (P < 0.05). PAT caused a significant dose-dependent increase in the number cells of NPBs, in the frequency of apoptotic and necrotic cells, and a significant dose-dependent decrease in the NDI values in lymphocytes. These results indicate that PAT at high concentrations is genotoxic, cytotoxic and cytostatic in cultured human lymphocytes.

Biosynthesis and toxicological effects of patulin

Patulin is a toxic chemical contaminant produced by several species of mold, especially within Aspergillus, Penicillium and Byssochlamys. It is the most common mycotoxin found in apples and apple-derived products such as juice, cider, compotes and other food intended for young children. Exposure to this mycotoxin is associated with immunological, neurological and gastrointestinal outcomes. Assessment of the health risks due to patulin consumption by humans has led many countries to regulate the quantity in food. A full understanding of the molecular genetics of patulin biosynthesis is incomplete, unlike other regulated mycotoxins (aflatoxins, trichothecenes and fumonisins), although the chemical structures of patulin precursors are now known. The biosynthetic pathway consists of approximately 10 steps, as suggested by biochemical studies. Recently, a cluster of 15 genes involved in patulin biosynthesis was reported, containing characterized enzymes, a regulation factor and transporter genes. This review includes information on the current understanding of the mechanisms of patulin toxinogenesis and summarizes its toxicological effects.

Reduction of patulin in apple cider by UV radiation

The presence of the mycotoxin patulin in processed apple juice and cider presents a continual challenge to the food industry as both consumer health and product quality issues. Although several methods for control and/or elimination of patulin have been proposed, no unifying method has been commercially successful for reducing patulin burdens while maintaining product quality. In the present study, exposure to germicidal UV radiation was evaluated as a possible commercially viable alternative for the reduction and possible elimination of the patulin mycotoxin in fresh apple cider. UV exposure of 14.2 to 99.4 mJ/cm(2) resulted in a significant and nearly linear decrease in patulin levels while producing no quantifiable changes in the chemical composition (i.e., pH, Brix, and total acids) or organoleptic properties of the cider. For the range of UV doses tested, patulin levels decreased by 9.4 to 43.4%; the greatest reduction was achieved after less than 15 s of UV exposure. The method of UV radiation (the CiderSure 3500 system) is an easily implemented, high-throughput, and cost-effective method that offers simultaneous UV pasteurization of cider and juice products and reduction and/or elimination of patulin without unwanted alterations in the final product.

Modeling Penicillium expansum resistance to thermal and chlorine treatments

Apples and apple products are excellent substrates for Penicillium expansum to produce patulin. In an attempt to avoid excessive levels of patulin, limiting or reducing P. expansum contamination levels on apples designated for storage in packinghouses and/or during apple juice processing is critical. The aim of this work was (i) to determine the thermal resistance of P. expansum spores in apple juice, comparing the abilities of the Bigelow and Weibull models to describe the survival curves and (ii) to determine the inactivation of P. expansum spores in aqueous chlorine solutions at varying concentrations of chlorine solutions, comparing the abilities of the biphasic and Weibull models to fit the survival curves. The results showed that the Bigelow and Weibull models were similar for describing the heat inactivation data, because the survival curves were almost linear. In this case, the concept of D- and z-values could be used, and the D-values obtained were 10.68, 6.64, 3.32, 1.14, and 0.61 min at 50, 52, 54, 56, and 60 degrees C, respectively, while the z-value was determined to be 7.57 degrees C. For the chlorine treatments, although the biphasic model gave a slightly superior performance, the Weibull model was selected, considering the parsimony principle, because it has fewer parameters than the biphasic model has. In conclusion, the typical pasteurization regimen used for refrigerated apple juice (71 degrees C for 6 s) is capable of achieving a 6-log reduction of P. expansum spores.

Influence of storage temperature and apple variety on patulin production by Penicillium expansum

This study examined the potential for patulin production in six different varieties of apples (Red Delicious, Golden Supreme, Gala, Fuji, Empire, and McIntosh) inoculated with Penicillium expansum spores and stored at two different temperatures (11 and 20.5 degrees C). Samples for patulin analysis were randomly taken from apples stored at different times, ranging from 21 to 93 days. While patulin was produced at both storage temperatures, apples incubated at 20.5 degrees C yielded significantly higher patulin concentrations than did those incubated at 11 degrees C. All apple varieties showed mold spoilage at both temperatures, except Red Delicious and Empire. A total of 44% of the samples analyzed showed patulin concentrations above the U.S. Food and Drug Administration regulatory limit (50 ppb). The highest patulin productions occurred in Golden Supreme (54,221 ppb) and McIntosh (52,131 and 48,457 ppb) varieties. Our results showed that careful culling of apples is essential for high juice quality, since high patulin levels in some apples varieties could result in a level greater than 50 ppb of this mycotoxin in the finished juice or cider, even when only one contaminated apple occurs in 1,000 apples.

Cold and ambient deck storage prior to processing as a critical control point for patulin accumulation

Patulin, a mycotoxin produced primarily by Penicillium expansum, is currently of great concern because of its undesirable effects in human health. It has been proven that patulin can damage organs and tissues in animals and some studies revealed carcinogenic and teratogenic effects. Patulin is found mainly in low quality apples diverted to production of apple by-products. Apples from cold storage or recently harvested (usually ground harvested or low quality apples) are stored under ambient conditions (deck storage) until they are processed. The present assay studies the consequences of this type of storage in development of lesions and patulin accumulation. The assayed factors were the size of lesions when apples were taken out from cold storage, time the apples stayed at room temperature after cold storage (as a simulation of deck storage) and intraspecific differences between 2 isolates of P. expansum. A sublot of P. expansum inoculated apples was cold stored until lesions achieved concrete sizes. Then, apples were either transferred to a 20 degrees C storage room for 0 to 5 days or were analysed for patulin immediately. The rest of the apples were directly stored at 20 degrees C. Each treatment had three replicates. Increase of lesion size with time at 20 degrees C depended on initial lesion size after cold storage. Bigger lesions were always achieved in apples with bigger initial lesion size. Initial lesion size and time at 20 degrees C significantly influenced patulin accumulation. No significant amounts of patulin were found in apples with lesions up to 2 cm after cold storage. Patulin amounts significantly increased on the 2nd day at 20 degrees C day and remained constant until the 5th day. Patulin accumulation tended to be higher when initial lesions were bigger. The assay showed the influence of apple quality (measured as overall lesion size) after cold storage on patulin accumulation during deck storage, as well as the importance of duration of deck storage. Quality of apples entering the processing plant should be assessed in order to program deck storage and minimise patulin accumulation. Predictive models of patulin accumulation as a function of time at room temperature and apple quality should be a useful tool to elaborators.

DNA–DNA cross-links contribute to the mutagenic potential of the mycotoxin patulin

The mycotoxin patulin (PAT), which occurs in various foods, induces mutations in cultured mammalian cells. However, the mechanism underlying the mutagenic potential of PAT is far from clear. In order to further clarify the mutagenic mode of action of PAT, we investigated the potential of PAT to induce DNA strand breaks, oxidative DNA modifications, and DNA-DNA cross-links using an alkaline filter elution technique and a fluorescence-based assay. In concentrations known to induce mutations in V79 cells (0.5-2.5 microM), PAT also induced DNA-DNA cross-links. In contrast, no effect on the number of DNA strand breaks (i.e., DNA single and double strand breaks as well as alkali-labile sites) or fpg-sensitive sites (i.e., oxidative DNA modifications) was observed in the non-cytotoxic concentration range. Thus, the present study demonstrates for the first time the direct reactivity of PAT towards DNA in a cellular system, which might have implications for the toxicological evaluation of this widespread mycotoxin.

Byssochlamys nivea with patulin-producing capability has an isoepoxydon dehydrogenase gene (idh) with sequence homology to Penicillium expansum and P. griseofulvum

Nucleotide sequences of the isoepoxydon dehydrogenase gene (idh) for eight strains of Byssochlamys nivea were determined by constructing GenomeWalker libraries. A striking finding was that all eight strains of B. nivea examined had identical nucleotide sequences, including those of the two introns present. The length of intron 2 was nearly three times the size of introns in strains of Penicillium expansum and P. griseofulvum, but intron 1 was comparable in size to the number of nucleotides present in introns 1 and 2 of P. expansum and P. griseofulvum. A high degree of amino acid homology (88%) existed for the idh genes of the strains of B. nivea when compared with sequences of P. expansum and P. griseofulvum. There were many nucleotide differences present, but they did not affect the amino acid sequence because they were present in the third position. The identity of the B. nivea isolates was confirmed by sequencing the ITS/partial LSU (28 S) rDNA genes. Four B. nivea strains were analysed for production of patulin, a mycotoxin found primarily in apple juice and other fruit products. The B. nivea strains produced patulin in amounts comparable to P. expansum strains. Interest in the genus Byssochlamys is related to the ability of its ascospores to survive pasteurization and cause spoilage of heat-processed fruit products worldwide.

Mycotoxin Patulin Activates the p38 Kinase and JNK Signaling Pathways in Human Embryonic Kidney Cells

Patulin (PAT), a mycotoxin mainly produced by Penicillium and Aspergillus, is frequently detected in moldy fruits and fruit products. Exposure of human embryonic kidney (HEK293) cells to PAT led to a dose- and time-dependent increase in the phosphorylation of two major mitogen-activated protein kinases (MAPKs), p38 kinase and c-Jun N-terminal kinase (JNK). The phosphorylated forms of MAPK kinase 4 (MKK4), c-Jun, and ATF-2 were also seen in PAT-treated cultures. The cell death caused by PAT was significantly reduced by the p38 kinase inhibitor, SB203580, but not by the JNK inhibitor, SP600125. Neither p38 kinase nor JNK played a role in the PAT-induced DNA damage. In PAT-treated cells, inactivation of double-stranded RNA-activated protein kinase R (PKR) by the inhibitor, adenine, markedly suppressed JNK and ERK phosphorylation. Treatment of HEK293 cells with PAT-cysteine adduct, a chemical derivative of PAT, showed no effect on MAPK signaling pathways, cell viability, or DNA integrity. These results indicate that PAT causes rapid activation of p38 kinase and JNK in HEK293 cells, but only the p38 kinase signaling pathway contributes to the PAT-induced cell death. PKR also plays a role in PAT-mediated MAPK activation.

Mutagenicity of the mycotoxin patulin in cultured Chinese hamster V79 cells, and its modulation by intracellular glutathione

Because the ability of the mycotoxin patulin (PAT) to cause gene mutations in mammalian cells is still ambiguous, we have studied the mutagenicity of PAT at the hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene locus in cultured Chinese hamster V79 cells with normal, depleted, and elevated glutathione (GSH) levels. PAT was more toxic to GSH-depleted cells than to normal cells and caused an increase of the intracellular GSH level in normal and GSH-depleted cells. It also caused synchronization of the cell cycle due to a temporary accumulation of cells in the G2/M phase; this G2/M arrest was more persistent in GSH-depleted than in normal cells. PAT gave rise to a clear and concentration-dependent induction of HPRT mutations at non-cytotoxic concentrations in V79 cells with normal GSH level; the lowest PAT concentration causing a significant number of mutant cells was 0.3 micromolar, and the mutagenic potency of PAT equaled that of the established mutagen 4-nitroquinoline-N-oxide. The mutagenicity of PAT was again more pronounced, by a factor of about three, in GSH-depleted V79 cells. Elevated GSH levels abolished all observed effects of PAT. These data support the notion that PAT is a mutagenic mycotoxin, in particular in cells with low GSH concentration. The ability of PAT to cause gene mutations in mammalian cells might have a bearing on its carcinogenicity.

Absorption of the mycotoxin patulin from the rat stomach

The mycotoxin patulin (PAT), which frequently occurs in apple juices, has previously been shown to be toxic and teratogenic. However, there is almost no data about its absorption and metabolism. Therefore, the enrichment of PAT in the tissue of perfused rat stomachs after luminal application and its vascular appearance was quantified by stable isotope dilution assays. After application of juices enriched with PAT at concentrations of 350 and 3.5 mg/l, respectively, the mycotoxin appeared almost instantly in the perfusate. Twenty-six to twenty-nine percent of PAT were removed from the gastric lumen over 55 min. From this quantity, 17% and 2% were transferred into vascular circulation and 3% and 0.06% were detectable in gastric tissue for the high and the low PAT dose, respectively. The disappearance of 8400 microg and 700 microg PAT, respectively, could be attributed in part to its reaction with intracellular glutathione (GSH). Regarding the GSH content in the tissue, a decrease of 87% compared to that of control stomachs was observed for the high PAT dose, whereas in the case of the low PAT dose no significant GSH degradation occurred. Thus our results show that even low concentrations of patulin penetrate the gastric wall. Toxic effects, however, are unlikely as most of the patulin is disintegrated.

Rapid degradation of the mycotoxin patulin in man quantified by stable isotope dilution assays

The absorption and degradation of the mycotoxin patulin in man was quantified by using a recently developed stable isotope dilution assay. Application of this currently most sensitive method revealed a patulin content less than 200 ng l(-1) in the blood serum of five consumers of apple juice. Likewise, no patulin was found in the serum of a volunteer, whose blood was drawn shortly after consumption of a juice containing a maximum tolerable amount of patulin. In further in vitro experiments, the degradation of patulin by reacting it with whole blood was investigated. After addition of 100 microg patulin to 9 ml blood, only 6.1% of the mycotoxin was detected after 2 min. It was concluded, therefore, that even high naturally occurring concentrations of patulin in foods are quickly degraded before reaching other tissues than the gastrointestinal tract.

Evaluation of genotoxic risk and oxidative DNA damage in mammalian cells exposed to mycotoxins, patulin and citrinin

Mycotoxins are fungal secondary metabolites with very diversified toxic effects in humans and animals. In the present study, patulin (PAT) and citrinin (CTN), two prevalent mycotoxins, were evaluated for their genotoxic effects and oxidative damage to mammalian cells, including Chinese hamster ovary cells (CHO-K1), human peripheral blood lymphocytes, and human embryonic kidney cells (HEK293). PAT, but not CTN, caused a significant dose-dependent increase in sister chromatid exchange (SCE) frequency in both CHO-K1 and human lymphocytes. PAT also elevated the levels of DNA gap and break in treated CHO-K1. In the single cell gel electrophoresis (SCGE) assay, exposure of HEK293 to concentrations above 15 microM of PAT induced DNA strand breaks; the tail moment values also greatly increased after posttreatment with formamidopyrimidine-DNA glycosylase (Fpg). This suggests that in human cells PAT is a potent clastogen with the ability to cause oxidative damage to DNA. However, no significant change in the tail moment values in CTN-treated cultures was found, suggesting that CTN is not genotoxic to HEK293. Incubation of HEK293 with CTN increased the mRNA level of heat shock protein 70 (HSP70), but not that of human 8-hydroxyguanine DNA glycosylase 1 (hOGG1). PAT treatment did not modulate the expression of either HSP70 or hOGG1 mRNA.

Patulin in apple-based foods: occurrence and safety evaluation

Patulin is a mycotoxin produced by certain species of Penicillium and Aspergillus, often detectable in mouldy fruits and their derivatives. On the basis of a PMTDI of 0.4 microgram/kg bw, limit values of 50 micrograms/kg or 50 micrograms/l of patulin have been set in fruit derivatives. To estimate the quantity of patulin that can be taken in with the diet, we analysed by HPLC samples of apples and apple derivatives which are most likely to be contaminated with patulin. In apple juices and in homogenized baby-foods, the mycotoxin concentration was always below the established limits, while in some samples of juice with pulp the mycotoxin content exceeded the safe levels. In rotten apples, not only was the amount of patulin extraordinarily high in the rotten area, but the mycotoxin had also spread to the part unaffected by mould. The data presented in this study indicate that the intake of patulin with apple derivatives is usually below the tolerable level of 0.4 microgram/kg bw/day, but since the patulin content in apples can vary considerably, the quality of fruits used in the production of apple derivatives should be strictly controlled in order not to exceed the safe limits.

Incidence of patulin in fruits and fruit juices marketed in Campinas, Brazil

One hundred and eleven samples of processed fruit juices (apple, grape, pineapple, papaya, guava, banana and mango) and 38 samples of sound fruits (apple, papaya, mango, pear and peach) produced and marketed in Brazil, were analysed for patulin by HPLC. Only one out of 30 samples of apple juice was found positive at 17 micrograms/l. Patulin was not detected in the other foodstuffs. It was found in 14 samples of spoiled fruit samples of apple (150-267 micrograms/kg), pear (134-245 micrograms/kg) and peach (92-174 micrograms/kg). Confirmation of the identity of patulin was based on the UV spectrum obtained by the HPLC diode array detector, compared with that of standard patulin, TLC developed by several solvent systems and sprayed with 3-methyl-2-benzothiazolinone hydrazone, and by acetylation with acetic anhydride.

Determination of patulin by reversed-phase high-performance liquid chromatography with extraction by diphasic dialysis

A simple and economical method has been developed for the determination of patulin in apple juice. The sample is extracted with ethyl acetate in a diphasic dialysis system, and the extract is cleaned up by elution from a Sep-Pak cartridge. Patulin is detected and determined by reversed-phase high-performance liquid chromatography using a Novapak C18 column and an ultraviolet detector. The lower detection limit is 1 microgram l-1 and the recovery is 85% at the 20 micrograms l-1 level.

Subacute toxicity study of patulin in the rat: effects on the kidney and the gastro-intestinal tract

Female and male Wistar rats were given drinking-water containing patulin at concentrations of 0, 24, 84 or 295 mg/litre citrate buffer (1 mM) for 4 wk. Compared with the controls, there were decreases in food and liquid intake by rats given the mid and high doses of patulin and the body weights of rats in the high-dose group were also decreased. The creatinine clearance in the high-dose group was lowered, although morphological glomerular damage was not observed. In the high-dose group, fundic ulcers in the stomach and enlargement and activation of the pancreatico-duodenal lymph nodes were noticed, while villous hyperaemia in the duodenum was observed in the mid- and high-dose groups. From the present data it can be concluded that high doses of patulin, administered via the drinking-water, caused effects on the kidney and gastro-intestinal tract. Since no changes in the relative weight or histological appearance of the adrenal glands were observed, it is suggested that the fundic ulcers in the stomach were caused by a direct effect of patulin and not indirectly (i.e. by stress).

Chemical carcinogens. A review and analysis of the literature of selected chemicals and the establishment of the Gene-Tox Carcinogen Data Base. A report of the U.S. Environmental Protection Agency Gene-Tox Program

The literature on 506 selected chemicals has been evaluated for evidence that these chemicals induce tumors in experimental animals and this assessment comprises the Gene-Tox Carcinogen Data Base. Three major sources of information were used to create this evaluated data base: all 185 chemicals determined by the International Agency for Research on Cancer to have Sufficient evidence of carcinogenic activity in experimental animals, 28 selected chemicals bioassayed for carcinogenic activity by the National Toxicology Program/National Cancer Institute and found to induce tumors in mice and rats, and 293 selected chemicals which had been evaluated in genetic toxicology and related bioassays as determined from previous Gene-Tox reports. The literature data on the 239 chemicals were analyzed by the Gene-Tox Carcinogenesis Panel in an organized, rational and consistent manner. Criteria were established to assess individual studies employing single chemicals and 4 categories of response were developed: Positive, Negative, Inconclusive (Equivocal) and Inconclusive. After evaluating each of the individual studies on the 293 chemicals, the Panel placed each of the 506 chemicals in an overall classification category based on the strength of the evidence indicating the presence or absence of carcinogenic effects. An 8-category decision scheme was established using a modified version of the International Agency for Research on Cancer approach. This scheme included two categories of Positive (Sufficient and Limited), two categories of Negative (Sufficient and Limited), a category of Equivocal (the evidence of carcinogenicity from well-conducted and well-reported lifetime studies had uncertain significance and was neither clearly positive nor negative), and three categories of Inadequate (the evidence of carcinogenicity was insufficient to make a decision, however, the data suggested a positive or negative indication). Of the 506 chemicals in the Gene-Tox Carcinogen Data Base, 252 were evaluated as Sufficient Positive, 99 as Limited Positive, 40 as Sufficient Negative, 21 as Limited Negative, 1 as Equivocal, 13 as Inadequate with the data suggesting a positive indication, 32 as Inadequate with the data suggesting a negative indication, and 48 Inadequate with the data not suggesting any indication of activity. This data base was analyzed and examined according to chemical class, using a 29 chemical class scheme.(ABSTRACT TRUNCATED AT 400 WORDS)

Mycotoxin induction of somatic mosaicism in Drosophila and DNA repair in mammalian liver cell cultures

The genotoxic activity of four mycotoxins has been studied. A high level of somatic mutagenesis in imaginal disk of Drosophila melanogaster larvae and DNA repair synthesis in human embryo and adult rat liver cells cultures was induced only by the strong carcinogen aflatoxin B1. Patulin somewhat elevated the level of somatic mutations in D. melanogaster, but did not elicit DNA repair synthesis. Citrinin and stachybotryotoxin were inactive in both systems.

Patulin mycotoxicosis in the rat: toxicology, pathology and clinical pathology

Patulin, a secondary metabolite produced by species of the genera Penicillium and Aspergillus, was administered to male Sprague-Dawley rats, weighing 50-60 g, by the oral, sc and ip routes. The 72-hr LD50 values (in mg/kg weight) were: oral, 55.0; sc, 11.0; ip, 10.0. Mortality was greatest 0-24 hr after administration by the oral and sc routes and 49-72 hr after ip dosing. Gross alterations consisted of gastric and intestinal hyperaemia and distention. Histopathological alterations consisted principally of ulceration and inflammation of the stomach. Patulin was administered orally to rats daily or every other day for 2 wk at doses of 50 or 75% of the oral LD50. Mortality in the treated groups was greater than in controls but was similar for all treated groups. No evidence of cumulative toxicity was found and the gross and histopathological alterations were similar to those found in the LD50 studies. Clinicopathological alterations included metabolic alkalosis with respiratory compensation, oliguria, decreased serum sodium, elevated blood glucose, reduced plasma protein and an elevated total leucocyte count which differential leucocyte counts indicated to be due to neutrophilia. The inflammatory alterations observed in the gastro-intestinal tract may be due to the irritant properties of patulin or to an alteration in the gastro-intestinal flora by the antibiotic activity of patulin.

Patulin, a further clastogenic mycotoxin, is negative in the SCE assay in Chinese hamster V79-E cells in vitro

Patulin is a potent inducer of chromatid-type aberrations in Chinese hamster V79-E cells, but loses its activity when 9000 g supernatant of rat-liver homogenate is added. The narrow dose range of patulin clastogenicity shows a quantitative relationship between absolute amount of mycotoxin applied and the number of indicator cells treated. Within a dose range permitting survival of V79-E, patulin does not induce an increase of the SCE rate. It is suggested that patulin clastogenicity is caused by interaction with chromosomal proteins and that DNA is not the virtual target of this mycotoxin.