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Jaćević V, Dumanović J, Alomar SY, Resanović R, Milovanović Z, Nepovimova E, Wu Q, Franca TCC, Wu W, Kuča K. Research update on aflatoxins toxicity, metabolism, distribution, and detection: A concise overview. Toxicology 2023; 492:153549. [PMID: 37209941 DOI: 10.1016/j.tox.2023.153549] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/07/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023]
Abstract
Serious health risks associated with the consumption of food products contaminated with aflatoxins (AFs) are worldwide recognized and depend predominantly on consumed AF concentration by diet. A low concentration of aflatoxins in cereals and related food commodities is unavoidable, especially in subtropic and tropic regions. Accordingly, risk assessment guidelines established by regulatory bodies in different countries help in the prevention of aflatoxin intoxication and the protection of public health. By assessing the maximal levels of aflatoxins in food products which are a potential risk to human health, it's possible to establish appropriate risk management strategies. Regarding, a few factors are crucial for making a rational risk management decision, such as toxicological profile, adequate information concerning the exposure duration, availability of routine and some novel analytical techniques, socioeconomic factors, food intake patterns, and maximal allowed levels of each aflatoxin in different food products which may be varied between countries.
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Affiliation(s)
- Vesna Jaćević
- Department for Experimental Pharmacology and Toxicology, National Poison Control Centre, Military Medical Academy, Crnotravska 17, 11000 Belgrade, Serbia; Medical Faculty of the Military Medical Academy, University of Defence, Crnotravska 17, 11000 Belgrade, Serbia; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic.
| | - Jelena Dumanović
- Medical Faculty of the Military Medical Academy, University of Defence, Crnotravska 17, 11000 Belgrade, Serbia; Department of Analytical Chemistry, Faculty of Chemistry, University of Belgrade, 11158 Belgrade, Serbia
| | - Suliman Y Alomar
- King Saud University, College of Science, Zoology Department, Riyadh, 11451, Saudi Arabia
| | - Radmila Resanović
- Faculty of Veterinary Medicine, University of Belgrade, Bulevar Oslobođenja 18, 11000 Belgrade, Serbia
| | - Zoran Milovanović
- Special Police Unit, Ministry of Interior, Trebevićka 12/A, 11 030 Belgrade, Serbia
| | - Eugenie Nepovimova
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Qinghua Wu
- College of Life Science, Yangtze University, 1 Nanhuan Road, 434023 Jingzhou, Hubei, China; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Tanos Celmar Costa Franca
- Laboratory of Molecular Modeling Applied to the Chemical and Biological Defense, Military Institute of Engineering, Praça General Tibúrcio 80, Rio de Janeiro, RJ 22290-270, Brazil; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Wenda Wu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China; MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
| | - Kamil Kuča
- Biomedical Research Center, University Hospital Hradec Kralove, 50005, Hradec Kralove, Czech Republic; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
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Nguyen VTT, König S, Eggert S, Endres K, Kins S. The role of mycotoxins in neurodegenerative diseases: current state of the art and future perspectives of research. Biol Chem 2021; 403:3-26. [PMID: 34449171 DOI: 10.1515/hsz-2021-0214] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/16/2021] [Indexed: 01/02/2023]
Abstract
Mycotoxins are fungal metabolites that can cause various diseases in humans and animals. The adverse health effects of mycotoxins such as liver failure, immune deficiency, and cancer are well-described. However, growing evidence suggests an additional link between these fungal metabolites and neurodegenerative diseases. Despite the wealth of these initial reports, reliable conclusions are still constrained by limited access to human patients and availability of suitable cell or animal model systems. This review summarizes knowledge on mycotoxins associated with neurodegenerative diseases and the assumed underlying pathophysiological mechanisms. The limitations of the common in vivo and in vitro experiments to identify the role of mycotoxins in neurotoxicity and thereby in neurodegenerative diseases are elucidated and possible future perspectives to further evolve this research field are presented.
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Affiliation(s)
- Vu Thu Thuy Nguyen
- Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University Mainz, Untere Zahlbacher Str. 8, D-55131 Mainz, Germany
| | - Svenja König
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, D-67663 Kaiserslautern, Germany
| | - Simone Eggert
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, D-67663 Kaiserslautern, Germany
| | - Kristina Endres
- Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg-University Mainz, Untere Zahlbacher Str. 8, D-55131 Mainz, Germany
| | - Stefan Kins
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, D-67663 Kaiserslautern, Germany
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Mrdjanovic J, Sudji J, Srdjenovic B, Dojcinovic S, Bogdanovic V, Jakovljevic DK, Jurisic V. Accidental Use of Milk With an Increased Concentration of Aflatoxins Causes Significant DNA Damage in Hospital Workers Exposed to Ionizing Radiation. Front Public Health 2020; 8:323. [PMID: 32850577 PMCID: PMC7396628 DOI: 10.3389/fpubh.2020.00323] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/12/2020] [Indexed: 11/29/2022] Open
Abstract
The occupational exposure to ionizing radiation (Irad) or associated with mycotoxin-contaminated food may lead to genome damage and contribute to health risk. DNA damage in 80 blood samples of hospital workers occupationally exposed to low-doses of Irad was compared with 80 healthy controls. Among them, 40 participants accidentally consumed milk with increased concentration of Aflatoxin. All participants underwent the testing for micronuclei from blood, and 40 of them 8-OHdG from urine. The frequency of micronuclei (MN) was analyzed by cytokinesis-block peripheral blood lymphocytes and the level of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) by ELISA. The Irad led to increased frequency of MN (p < 0.05) and 8-OHdG level at exposed hospital workers. The consumption of milk with increased concentration of aflatoxin probably raised MN frequency and 8-OHdG value. Higher consumption of aflatoxin-contaminated milk (≥2 L/monthly) caused significantly increased MN frequency and 8-OHdG value in comparison to lower milk intake (≤0.5 L/monthly). Also, confounding factors, such as age, gender, and smoking status of all participants were included in the study. The obtained results revealed an increased incidence of MN and 8-OHdG level among hospital workers exposed to low-doses of IRad and milk with increased aflatoxin concentration.
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Affiliation(s)
- Jasminka Mrdjanovic
- Faculty of Medicine, Oncology Institute of Vojvodina, University of Novi Sad, Sremska Kamenica, Serbia
| | - Jan Sudji
- Institute of Occupational Health, Novi Sad, Serbia
| | - Branislava Srdjenovic
- Department of Pharmacy, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | | | - Visnja Bogdanovic
- Faculty of Medicine, Oncology Institute of Vojvodina, University of Novi Sad, Sremska Kamenica, Serbia
| | | | - Vladimir Jurisic
- Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
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Degradation of AFB1 in aqueous medium by electron beam irradiation: Kinetics, pathway and toxicology. Food Control 2016. [DOI: 10.1016/j.foodcont.2016.02.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Jardon-Xicotencatl S, Díaz-Torres R, Marroquín-Cardona A, Villarreal-Barajas T, Méndez-Albores A. Detoxification of Aflatoxin-Contaminated Maize by Neutral Electrolyzed Oxidizing Water. Toxins (Basel) 2015; 7:4294-314. [PMID: 26512692 PMCID: PMC4626735 DOI: 10.3390/toxins7104294] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 10/14/2015] [Accepted: 10/15/2015] [Indexed: 01/05/2023] Open
Abstract
Aflatoxins, a group of extremely toxic mycotoxins produced by Aspergillus flavus, A. parasiticus and A. nomius, can occur as natural contaminants of certain agricultural commodities, particularly maize. These toxins have been shown to be hepatotoxic, carcinogenic, mutagenic and cause severe human and animal diseases. The effectiveness of neutral electrolyzed oxidizing water (NEW) on aflatoxin detoxification was investigated in HepG2 cells using several validation methodologies such as the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide assay, the induction of lipid peroxidation, the oxidative damage by means of glutathione modulation, the Ames test and the alkaline Comet assay. Our results showed that, after the aflatoxin-contaminated maize containing 360 ng/g was soaked in NEW (60 mg/L available chlorine, pH 7.01) during 15 min at room temperature, the aflatoxin content did not decrease as confirmed by the immunoaffinity column and ultra performance liquid chromatography methods. Aflatoxin fluorescence strength of detoxified samples was similar to untreated samples. However, aflatoxin-associated cytotoxicity and OPEN ACCESS Toxins 2015, 7 4295 genotoxicity effects were markedly reduced upon treatment. According to these results, NEW can be effectively used to detoxify aflatoxin-contaminated maize.
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Affiliation(s)
- Samantha Jardon-Xicotencatl
- UNAM-FESC. Campus 4. Multidisciplinary Research Unit L14 (Food, Mycotoxins and Mycotoxicosis), Cuautitlan Izcalli 54714, Mexico.
| | - Roberto Díaz-Torres
- UNAM-FESC. Campus 4. Multidisciplinary Research Unit L9 (Toxicology and Genetics), Cuautitlan Izcalli 54714, Mexico.
| | | | | | - Abraham Méndez-Albores
- UNAM-FESC. Campus 4. Multidisciplinary Research Unit L14 (Food, Mycotoxins and Mycotoxicosis), Cuautitlan Izcalli 54714, Mexico.
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Qureshi H, Hamid SS, Ali SS, Anwar J, Siddiqui AA, Khan NA. Cytotoxic effects of aflatoxin B1 on human brain microvascular endothelial cells of the blood-brain barrier. Med Mycol 2015; 53:409-16. [DOI: 10.1093/mmy/myv010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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Iqbal J, Asghar MA, Ahmed A, Khan MA, Jamil K. Aflatoxins contamination in Pakistani brown rice: a comparison of TLC, HPLC, LC–MS/MS and ELISA techniques. Toxicol Mech Methods 2014; 24:544-51. [DOI: 10.3109/15376516.2014.948247] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Khan MA, Asghar MA, Iqbal J, Ahmed A, Shamsuddin ZA. Aflatoxins contamination and prevention in red chillies (Capsicum annuum L.) in Pakistan. FOOD ADDITIVES & CONTAMINANTS PART B-SURVEILLANCE 2013; 7:1-6. [PMID: 24779970 DOI: 10.1080/19393210.2013.825330] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
During 2006-2011, 331 red chilli samples (226 whole, 69 powdered and 36 crushed) were collected from all over Pakistan for the estimation of total aflatoxins (AFs = AFB1 + AFB2 + AFG1 + AFG2) contamination by thin layer chromatography (TLC). Mean AFs levels in whole, powdered and crushed chillies were 11.7, 27.8 and 31.2 µg kg(-1), respectively. AFs levels in 62.4% of whole, 26.1% of powdered and 19.4% of crushed chillies were found lower than the maximum limit (ML = 10 µg kg(-1)) as assigned by the European Union. Furthermore, whole (27.9%), powdered (28%) and crushed (27.8%) chillies showed AFs contamination which ranged between 10 and 20 µg kg(-1). However, 9.7% of whole, 46% of powdered and 52.8% of crushed chillies showed AFs levels beyond the ML of 20 µg kg(-1) as assigned by the USDA. It was concluded that AFs contamination in chillies requires further investigation, monitoring and routine analysis. Furthermore, proper harvesting, drying, handling, storage and transport conditions need to be employed.
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Affiliation(s)
- Mobeen Ahmed Khan
- a Food and Feed Safety Laboratory , Food and Marine Resources Research Centre, PCSIR Laboratories Complex , Karachi , Pakistan
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Chang M, Jin Q, Liu Y, Liu R, Wang X. Efficiency and safety evaluation of photodegradation of Aflatoxin B1on peanut surface. Int J Food Sci Technol 2013. [DOI: 10.1111/ijfs.12238] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ming Chang
- State Key Laboratory of Food Science and Safety; Synergetic Innovation Center of Food Safety and Nutrition; School of Food Science and Technology; Jiangnan University; 1800 Lihu Road Wuxi 214122 Jiangsu China
| | - Qingzhe Jin
- State Key Laboratory of Food Science and Safety; Synergetic Innovation Center of Food Safety and Nutrition; School of Food Science and Technology; Jiangnan University; 1800 Lihu Road Wuxi 214122 Jiangsu China
| | - Yuanfa Liu
- State Key Laboratory of Food Science and Safety; Synergetic Innovation Center of Food Safety and Nutrition; School of Food Science and Technology; Jiangnan University; 1800 Lihu Road Wuxi 214122 Jiangsu China
| | - Ruijie Liu
- State Key Laboratory of Food Science and Safety; Synergetic Innovation Center of Food Safety and Nutrition; School of Food Science and Technology; Jiangnan University; 1800 Lihu Road Wuxi 214122 Jiangsu China
| | - Xingguo Wang
- State Key Laboratory of Food Science and Safety; Synergetic Innovation Center of Food Safety and Nutrition; School of Food Science and Technology; Jiangnan University; 1800 Lihu Road Wuxi 214122 Jiangsu China
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Liu R, Jin Q, Huang J, Liu Y, Wang X, Zhou X, Mao W, Wang S. In vitro toxicity of aflatoxin B1 and its photodegradation products in HepG2 cells. J Appl Toxicol 2011; 32:276-81. [DOI: 10.1002/jat.1669] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/13/2011] [Accepted: 01/13/2011] [Indexed: 12/20/2022]
Affiliation(s)
- Ruijie Liu
- State Key Laboratory of Food Science and Safety; School of Food Science and Technology; Jiangnan University; China
| | - Qingzhe Jin
- State Key Laboratory of Food Science and Safety; School of Food Science and Technology; Jiangnan University; China
| | - Jianhua Huang
- State Key Laboratory of Food Science and Safety; School of Food Science and Technology; Jiangnan University; China
| | - Yuanfa Liu
- State Key Laboratory of Food Science and Safety; School of Food Science and Technology; Jiangnan University; China
| | - Xingguo Wang
- State Key Laboratory of Food Science and Safety; School of Food Science and Technology; Jiangnan University; China
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Ameen Abdulmajeed N. Therapeutic ability of some plant extracts on aflatoxin B1 induced renal and cardiac damage. ARAB J CHEM 2011. [DOI: 10.1016/j.arabjc.2010.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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BRAICU CORNELIA, BERINDAN-NEAGOE IOANA, CHEDEA VERONICASANDA, BALACESCU LOREDANA, BRIE IOANA, SORITAU OLGA, SOCACIU CARMEN, IRIMIE ALEXANDRU. INDIVIDUAL AND COMBINED CYTOTOXIC EFFECTS OF THE MAJOR FOUR AFLATOXINS IN DIFFERENT IN VITRO STABILIZED SYSTEMS. J Food Biochem 2010. [DOI: 10.1111/j.1745-4514.2010.00350.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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M. Mohamed A, S. Metwall N. Antiaflatoxigenic Activities of Some Plant Aqueous Extracts Against Aflatoxin-B1 Induced Renal and Cardiac Damage. ACTA ACUST UNITED AC 2008. [DOI: 10.3923/jpt.2009.1.16] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Gursoy N, Sarac B, Durmus N, Parlak A, Yildirim S, Kaya T, Bagcivan I. Changes in spontaneous contractions of rat ileum by aflatoxin in vitro. Food Chem Toxicol 2008; 46:2124-7. [PMID: 18353519 DOI: 10.1016/j.fct.2008.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 01/31/2008] [Accepted: 02/04/2008] [Indexed: 10/22/2022]
Abstract
Aflatoxins are a group of mycotoxins produced by toxigenic strains of Aspergillusflavus, Aspergillusparasiticus and Aspergillusnomius as secondary metabolites. Most of the studies on the aflatoxins have focused mainly on their chronic toxic effects but aflatoxins have also a lot of acute effects on the respiratory, cardiovascular and gastrointestinal systems. In this study the acute gastrointestinal effects of the aflatoxins on rat isolated ileum and the possible mechanisms underlying contractile responses to them were investigated. Aflatoxin increased both of the amplitude and the frequency of spontaneous contractions in a dose-dependent manner. Pretreatment with a cholinergic system inhibitor, atropine sulfate (23.6nM), a specific sodium-channel blocker, tetrodotoxin (0.3microM) and an inhibitor of ACh release from terminal motor neurons, morphine (0.3microM) decreased both of aflatoxin induced spontaneous contractions' amplitude and frequency, in contrast a nicotinic ganglionic blocker, hexamethonium chloride (55microM) did not change the aflatoxin effect. But the decrease of amplitude was more than the frequency in the presence of these antagonists. In conclusion, these findings of aflatoxin on isolated rat ileum may explain their acute gastrointestinal effects in humans and animals.
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Affiliation(s)
- Nevcihan Gursoy
- Faculty of Engineering, Department of Food Engineering, Cumhuriyet University, 58140 Sivas, Turkey.
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Amici M, Cecarini V, Pettinari A, Bonfili L, Angeletti M, Barocci S, Biagetti M, Fioretti E, Eleuteri AM. Binding of aflatoxins to the 20S proteasome: effects on enzyme functionality and implications for oxidative stress and apoptosis. Biol Chem 2007; 388:107-17. [PMID: 17214555 DOI: 10.1515/bc.2007.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aflatoxins (AF) are contaminants of improperly stored foods; they are potent genotoxic and carcinogenic compounds, exerting their effects through damage to DNA. They can also induce mutations that increase oxidative damage. The goal of this study was to evaluate the possibility that a third mechanism could be involved in the carcinogenic action of aflatoxins, namely, direct binding to key enzymes involved in the regulatory pathways of the cell cycle, thereby modulating enzyme functionality. The 20S constitutive and immunoproteasome peptidase and proteolytic activities were assayed in the presence of aflatoxins B1, G1 and M1. All three toxins activated multiple peptidase activities of the proteasome. Aflatoxin (AF) M1 was the most potent activator of proteasome activity, while the constitutive 20S proteasome was specifically stimulated by AFG1. Furthermore, the effects of AFB1 on cultured hepatoma cells were investigated and the various proteasomal activities determined with cell lysates were differently affected. Taking into account the key role of the proteasome in cellular defense against oxidative stress, the carbonyl group content and the activities of antioxidant enzymes in cell lysates were analyzed. The proapoptotic effect of AFB1 was also investigated by measuring caspase-3 activity and cellular levels of p27 and IkappaBalpha.
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Affiliation(s)
- Manila Amici
- Department of Molecular, Cellular and Animal Biology, University of Camerino, I-62032 Camerino (MC), Italy
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Szkudelska K, Drzymała H, Szkudelski T, Bukowska K, Nogowski L. Lack of the effect of mycotoxins-aflatoxin B1 and ochratoxin A on some functions of rat adipocytes. Toxicol In Vitro 2005; 19:771-7. [PMID: 15963681 DOI: 10.1016/j.tiv.2005.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mycotoxins-aflatoxin B1 (AFB1) and ochratoxin A (OTA)-compounds which are strong carcinogenic, mutagenic and cytotoxic factors-are also known to evoke a decrease of food intake and body weight gains. The purpose of our study was to determine the direct influence of AFB1 and OTA incubated with isolated rat fat cells on the lipogenesis, lipolysis and leptin secretion. Adipocytes were isolated from the epididymal fat tissue by the collagenase digestion. Toxins used at concentrations 1, 10 and 100 microM were incubated for 90 min with adipocytes. Basal and insulin-stimulated lipogenesis-determined by the measure of [U-14C]glucose conversion to total lipids-was abated by AFB1 only at the highest concentration. At two lower ones, AFB1 did not affect the process. OTA at all used concentrations decreased insulin-stimulated lipogenesis but the effect was not dose-dependent. The lipolysis was determined by the measure of glycerol release from adipocytes. The basal lipolysis was unchanged by both toxins. The epinephrine-stimulated lipolysis was intensified by AFB1 only at the highest concentration, however, the process was not altered by OTA. The antilipolytic action of insulin was unaffected by both compounds (10 microM). To determine the influence of the tested toxins on leptin secretion, adipocytes were incubated for 120 min in the presence of glucose and insulin as stimulators of hormone secretion. AFB1 and OTA added to the incubation medium (1, 10 and 100 microM) had no significant influence on the leptin release. The results obtained in this experiment demonstrate that adipocytes are susceptible to the direct action of AFB1 and OTA. This susceptibility is, however, rather weak and is exhibited by a slight restriction of the lipogenesis (in the case of both toxins) and by a slight increase of the lipolysis (in the case of AFB1).
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Affiliation(s)
- K Szkudelska
- Department of Animal Physiology and Biochemistry, August Cieszkowski University of Agriculture, 60-637 Wołyńska 35, Poznań, Poland.
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Abstract
Previous studies on the aflatoxins have focused mainly on their chronic toxic effects. In this study we investigated the acute gastrointestinal effects of four common aflatoxins on isolated guinea pig ileum. AFB(1) (EC(50) 4.6+/-0.4 microM) and AFB(2) (EC(50)17+/-4.4 microM) contracted isolated guinea pig ileum in a dose-dependent manner, whereas AFG(1) and AFG(2) evoked no contractions. Atropine (5.9 nM 11.8 and 23.6 nM) antagonized AFB(1)-induced contractions in a dose-dependent manner. Pretreatment with the nicotinic ganglionic blocker, hexamethonium (up to 55 microM), left AFB(1)-induced contractions unchanged. In contrast, tetrodotoxin (0.3 microM), blocked AFB(1) contractile activity. The two inhibitors of ACh release, morphine (0.3 microM) and clonidine (0.4 microM), antagonized EC(50) AFB(1)-induced contractions, and apamin, a drug that increases neuronal excitability, facilitated the EC(50) AFB(1)-induced contractile effect. The choline uptake blocker, hemicholinium (17.4 microM) markedly reduced AFB(1)-induced contractions. These results suggest that aflatoxins induce their contractile effect indirectly through the cholinergic system by stimulating acetylcholine release from the postganglionic parasympathetic nerve endings. The acute actions of aflatoxins on isolated guinea pig ileum could explain their acute gastrointestinal effects in humans and animals.
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Affiliation(s)
- A Luzi
- Department of Pharmacology of Natural Substances and General Physiology, University of Rome La Sapienza, P. le A. Moro 5, 00185 Rome, Italy
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Jayashree T, Praveen Rao J, Subramanyam C. Regulation of aflatoxin production by Ca(2+)/calmodulin-dependent protein phosphorylation and dephosphorylation. FEMS Microbiol Lett 2000; 183:215-9. [PMID: 10675586 DOI: 10.1111/j.1574-6968.2000.tb08960.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
To elucidate Ca(2+)-mediated regulation of aflatoxin production, the status of Ca(2+)/calmodulin-dependent protein phosphorylation and dephosphorylation was investigated employing toxigenic and non-toxigenic strains of Aspergillus parasiticus. Incubation of cytoplasmic extracts with [gamma-(32)P]ATP followed by SDS-PAGE and autoradiography revealed total absence of protein phosphorylation during periods corresponding to aflatoxin production in the toxigenic strain (NRRL 2999). In contrast, protein phosphorylation was unaffected in the non-toxigenic strain (SRRC 255). Aflatoxin production in the toxigenic strain was also accompanied by enhanced (26-fold) activity of calcineurin (calmodulin-dependent protein phosphatase 2B) concomitant with a lowered (6-fold) activity of calmodulin-dependent protein kinase. In addition, the in vitro activity of Ca(2+)/calmodulin-dependent protein kinase was susceptible to dose-dependent inhibition by aflatoxin. Since calcineurin remains active in the absence of phosphorylation by calmodulin-dependent protein kinase, it is suggested that calcineurin-mediated dephosphorylation of regulatory enzymes ensures continued production of aflatoxins.
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Affiliation(s)
- T Jayashree
- Department of Biochemistry, University College of Science, Osmania University, Hyderabad, India
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