جستجوی مقالات مرتبط با کلیدواژه « آفلاتوکسین B1 » در نشریات گروه « زیست شناسی »

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.

According to the FAO annual report, 10 percent of the world's food products are contaminated with fungal toxins, among which aflatoxins have the most contribution as compared to others. This research was aimed to assess the ability of Lactobacillus rhamnosus strain GG in the reduction of aflatoxin B1 (AFB1) in a simulated human gastrointestinal tract containing sterilized milk.   For this purpose, the bacterial count and aflatoxin concentration were adjusted to 1×1010 cfu/ml and 5 ppm, respectively, where artificial gastrointestinal tract discharges were inoculated in the simulated environment. In this study 6 treatment groups were assessed in the presence and absence of bacteria, sterilized milk, and gastrointestinal juice suspension. The concentration of residual aflatoxin was determined using high-performance liquid chromatography (HPLC) and purification by Immunoaffinity column.   The reduction of aflatoxin B1 at all treatments was determined using HPLC with a detection limit of 0.25 mg/ml and a quantification limit of 0.75 mg/ml. The mycotoxin recovery rate was between 89% and 94% for AFB1. The aflatoxin B1 calibration curve with a correlation coefficient of 0.95 was linear in the concentration range of 1 to 10 ng/ml. The highest and lowest average removal percentage of aflatoxin B1 was observed for 5 and 1 treatments (58.8 ± 0.018 and 13.86 ± 0.017) respectively, where a significant difference in removal percentage was observed among six treatment groups.   The results indicated that beside L. rhamnosus strain GG, gastric and small intestine juices are suitable to eliminate or reduce aflatoxin B1, as well.

Aspergillus flavus is among of fungi that caused massive contamination on feed. In this study، was study antifungal activity of different extracts of Aloe Vera plant on the growth، aflatoxin production and also its effect on profile of extracellular proteins of Aspergillus flavus. Six different solvents، acetone، ethanol، water، methanol، chloroform and ethyl ether were employed for extraction from Aloe Vera fresh leaves. Antifungal activity of the extracts was evaluated by Agar Plate Diffusion Plate method، using doses of 0، 2، 20، 200 and 2000µL in 20mL. Also، the acetone extract of Aloe Vera were used to evaluate and study on the production of aflatoxin B1 and extracellular protein patterns produced by A. flavus by HPLC and SDS-PAGE respectively. The maximum antifungal activity was observed in acetone extract، in concentration of 2000µL. Results obtained from HPLC analysis revealed the inhibition of aflatoxin production in 2000µL for 40. 94% and in 2µL for 18. 14%. The SDS-PAGE results showed that with decrease in fungal mycelium growth، the proteins production rate was also decreased. From this study it can be concluded that the acetone extract of Aloe Vera can be used as a more effective antifungal agent to inhibit the growth of A. flavus compared to other solvents.