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Background: Differentiation ofmesenchymal stem cells (MSCs) to hepatocyte-like cells could be associated with development of liver function factors. The impact of differentiation-dependent changes on DNA integrity is not well understood. In this study, hepatocytes and their progenitor stem cells were treated with aflatoxin B1 (AFB1) and amplification of selected genes linked to DNA damage was examined. Methods: MSCs and CD34+ cells isolated from umbilical cord blood (UCB) were treated with AFB1 (0, 2.5, 10 and 20 µM) in selective media supporting the hepatocyte differentiation. After 24 htreatment the DNA damage (Comet assay) and amplification rates ofP53 and β-globin genes were measured using real time polymerase chain reaction (QPCR). Results:The results show that AFB1 treatments resulted in a concentration- dependent increase in the DNA damage and suppression of the specific gene amplification. The extent of DNA damage was significantly greater in hepatocytes differentiated from MSCs when compared to those obtained from CD34+ cells. The effects of AFB1 on the rate of selected gene amplification in QPCR showed that the lesions (expressed as lesions/10 kb) in P53 and β-globin genes was significantly greater in hepatocytes derived from MSCs as compared to the cells derived from CD34+ cells. Conclusions: These data together with the results of cytochrome P450 (CYP3A4) expression in the cells suggest that the non-differentiated stem cells are probably less vulnerable to genotoxic agents as compared to hepatocytes differentiated from them.

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Aflatoxins are among the secondary metabolites of moulds that have the most toxicity between the mycotoxins. Different physical, chemical and biological approaches have been evaluated to detoxify the aflatoxins. One of the biological methods to detoxify the aflatoxin is using beneficial microorganisms such as lactic acid bacteria to remove the toxin. A lot of studies believed that physical attachment of lactobacilli to mutagens and removing them is the main protection factor. In this study the potential of some of lactobacilli that have been isolated from traditional dairy products to absorb and remove aflatoxin B₁ was investigated through ELISA and HPLC methods. The results obtained from screening the lactobacilli through ELISA method indicated the difference potential of lactobacilli in detoxification of aflatoxin B₁. Comparison the results of ELISA and HPLC methods obtained point out that ELISA as a rapid and easy method is a suitable approach in initial screening of isolates with potential of aflatoxin B₁ detoxification but for next steps more sensitive methods such as HPLC should be used. Complementary in vitro and in vivo studies could lead to introduce Iranian native isolates that have potential to apply in related industries. Such isolates could be used in food and feed industries to detoxify the aflatoxin B₁.  بررسی توانایی سویه های لاکتوباسیل جدا شده از فرآورده­های لبنی سنتی در حذف آفلاتوکسین B₁   مریم تاج آبادی ابراهیمی¹ *، هدی بهرامی² ، مریم هاشمی³، منصوره مظاهری⁴، پروانه جعفری⁵
* مسئول مکاتبات: m.tajabadi@iauctb.ac.ir

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Objective: With consideration of lethal effects of aflatoxins specially B1 on human health. Estimation of aflatoxin-albumin adduct, as an important marker of aflatoxin exposure, seems essential. The aim of this study is optimization of HPLC-fluorescence method for measurement of this important marker in blood serum. Materials and Methods: In this study, blood serum of three groups of rats as A) positive controls (treated with AFB1), B) negative controls (without treatment) and standard rats (treated with radiolabeled AFB1) were used. After albumin isolation using ammunium sulphate and acetic acid, purity of albumin was tested by SDS-PAGE electrophoresis and albumin concentration was quantified by bradford method. Then albumin was hydrolysed by pronase and aflatoxin bound to albumin was released as aflatoxin-lysine. Pronase was precipitated and albumin was digested by aceton in cold, the volume of supernatant was reduced by freeze-drier and injected into HPLC system. Aflatoxin was quantified in comparison to standard rats samples. Results: The purity of this isolated albumin was confirmed by SDS-PAGE electrophoresis. Albumin concentration in positive, negative and standard samples were 10, 13 and 12.5 mg/ml, respectively. Detection limit (20 pg/mg Alb) for measurement of aflatoxin was determined by HPLC method, specificity and sensitivity of method were 92% and 100% respectively. The mean concentration of AF-Alb adducts in serum of positive control rats was 10 ng/mg Alb and the reproducibility of the method after several repeat was very good. Conclusion: In this study, for AF-Alb adduct quantification by HPLC method, mobile phase, percentage of solvents and run time were changed and the affinity chromatography before HPLC, was deleted. Therefor HPLC- fluorescence which is a precise and specific method, and since it is fast, highly reproducible and cost effective, also with improvement made, could easily be used for the quantification of this important marker in serum.

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Aflatoxin B1 is a type of mycotoxin produced by Aspergillus fungi during food production and storage. Aflatoxins have many toxic effects on the body that cause mutagens, teratogens and have high carcinogenic properties that cause cancer in the liver and other organs. Although conventional device methods for measuring aflatoxin B1 in food are sensitive and accurate, they have disadvantages such as high diagnostic time, high cost, the need for a trained user, and the creation of false positive results. Therefore, the development of new measuring methods has been prioritized by researchers. Among these measurement methods is the use of biosensors, which are fast, simple and more affordable and are used in the food industry today. In this work, a colorimetric optical aptasensor using gold nanoparticles with appropriate sensitivity and high selectivity was used to detect aflatoxin B1 in serum and buffer. For this purpose, gold nanoparticles were synthesized by reducing HAuCl₄ by sodium citrate (with a size of 14.40 nm and a zeta potential of -27.5). In this method, the protective effect of DNA sequence on the surface of gold nanoparticles has been used in the presence or absence of aflatoxin with the intervention of salt and the characteristic of visual color change. The detection limit of this method was estimated to be 50 ng/L and its linear range was 200-28000 ng/L. As a result, the designed aptasensor can be used for quick identification and screening of this toxin in contaminated food.
 

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This study was conducted to investigate the effect of Aflatoxin B₁ (AFB₁) on performance and egg quality in broiler breeders and the abatement of its deteriorative effect through its counteraction with Herbal Mycotoxin Binder (HMB). Thirty-six, 28-wk-old broiler breeder hens were allotted to one of the three treatments of: (1) basal diet (control),(2) control plus 500 μg kg^-1 AFB₁ and (3) control diet plus 500 μg kg^-1 AFB₁+0.2%HMB for three periods, each of a duration of three weeks and when from 28 to 36 weeks of age. Results revealed that 500 μg kg^-1 AFB₁ significantly (P< 0.05) reduced feed consumption, feed efficiency, egg production as well as egg weight. Supplementation of HMB partially restored feed consumption and egg production alleviating some side effects of AFB₁.

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Objective: The concern about the presence of aflatoxin and its risk for human and animal health has resulted in the introduction of different methods to eliminate or reduce this toxin. One of these methods is biological control of the fungus by other microorganisms. Methods: We isolated a strain of Bacillus amyloliquefaciens from the soil of a pistachio orchard, Damghan, Iran. This strain was applied as a biological control to examine the inhibition of growth and toxin production by Aspergillus parasiticus NRRL2999. After 72 hours of incubation of the bacterium at 30°C, we separated the supernatant as a potential source for antifungal compounds. Different doses of the supernatant were co-cultured with the fungus suspension in glucose yeast extract broth (GYB) at 28°C for 4 days. After the incubation period, we measured the inhibition of fungal growth by dry weight assessment of the fungal mass. We performed qualitative and quantitative assessment to determine the amount of aflatoxin B₁ by TLC and HPLC, respectively. Results: Increased bacterial culture supernatant as the antagonist in fungal growth medium resulted in decreased fungal growth. AFB₁ production was 2.35 ppm in control samples, whereas the amount considerably decreased in samples treated by the bacterial supernatants. The toxin reduction was dose-dependent. Conclusion: The results of this study have shown that this bacterial strain, by taking into consideration its native origin, can be used as a biological control against aflatoxigenic fungi.

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Because food contamination with mycotoxins is a serious problem, in this study, the ability of aflatoxin B1 to bind to the Saccharomyces cerevisiae cell wall was investigated to reduce Sangak bread dough toxicity. For this purpose, aflatoxin B1 at a concentration of 10 μg/kg inoculated to the dough containing 0.27 g of viable saccharomyces cerevisiae, acid treated saccharomyces cerevisiae, and ultrasonicated saccharomyces cerevisiae. Toxin adsorption kinetics were investigated at 24, 28 and 32 °C and 8, 16 and 24 h incubation. The trend for toxin adsorption was as follows: ultrasonicated yeast ˃ acidic yeast ˃ viable yeast. With increasing the incubation temperature and time, toxin adsorption increased in acid treated and ultrasonicated Saccharomyces cerevisiae, while active yeast samples showed the highest toxin removal at 28 °C. The results showed that the adsorption kinetics by active yeast and acid treated yeast could be explained by means of pseudo first order model, while for the ultrasonicated yeast, the data are more consistent with the pseudo second order model. Also, both surface adsorption and intra-particle diffusion contributed to the adsorption rate steps. Therefore, live or non-living yeast cells are suitable biological agents for aflatoxin removal in a contaminated culture medium, however, ultrasonic treatment is more effective.