The effect of Propolis on inhibition of Aspergillus parasiticus growth, aflatoxin production and expression of aflatoxin biosynthesis pathway genes

Determination of aflatoxin M1 and ochratoxin A in breast milk in rural centers of Yazd, Iran: Exposure assessment and risk characterization

Breast milk (BM) is considered as the best source of nutrition which could have prevention effects on various diseases in the first years of a child. Along with nutritive compounds, presence of contaminants such as mycotoxins in BM could be transmitted into neonate. The aim of this study was to determine the occurrence, levels, and factors associated with the presence of aflatoxin M1 (AFM1) and ocratoxin a (OTA) in BM samples of nursing mothers in rural centers of Yazd, Iran. The presence and average AFM1 and OTA concentration in 72 BM samples was measured by competitive ELISA. The demographic and diet parameters of nursing mothers were collected by a questionnaire and were analyzed using SPSS 18 software. AFM1 and OTA were detected in 63 (87.5%) and 47 (65.2%) samples with the mean concentration levels of 19.46 ± 13.26 ng/L (ranges from 5.1 to 53.9) and 200 ± 160 ng/L (ranges from 100 to 2460), respectively. Of these, 32 samples (50.7%) for AFM1 and 23 samples (48.9%) for OTA had values exceeding the limit set by the European Union regulation for infant foods (25 ng/L for AFM1 and 500 ng/L for OTA). It was also found that the risk of AFM1 and OTA occurrence in BM increased significantly with the consumption of beans, bread, cereals, fruit juice and crackers, and cream, respectively. This study showed that the estimated daily intake for AFM1 and OTA by 1 month of age infants was 2.7 and 28.5 ng/kg bw/day, respectively, while, as the age of the infant increased, the values were lower and close to 0.9 and 9.9 ng/kg bw/day for AFM1 and OTA in 12 months of age infants, respectively. The high occurrence and noticeable levels of AFM1 and OTA detected in this study indicated that some infants receive undesirable exposures to AFM1 and OTA with breast milk. Therefore, it is recommended that mothers are advised to avoid certain foods during pregnancy and breastfeeding that are likely sources of mycotoxins.

Aspergillus-bees: A dynamic symbiotic association

Besides representing one of the most relevant threats of fungal origin to human and animal health, the genus Aspergillus includes opportunistic pathogens which may infect bees (Hymenoptera, Apoidea) in all developmental stages. At least 30 different species of Aspergillus have been isolated from managed and wild bees. Some efficient behavioral responses (e.g., diseased brood removal) exerted by bees negatively affect the chance to diagnose the pathology, and may contribute to the underestimation of aspergillosis importance in beekeeping. On the other hand, bee immune responses may be affected by biotic and abiotic stresses and suffer from the loose co-evolutionary relationships with Aspergillus pathogenic strains. However, if not pathogenic, these hive mycobiota components can prove to be beneficial to bees, by affecting the interaction with other pathogens and parasites and by detoxifying xenobiotics. The pathogenic aptitude of Aspergillus spp. likely derives from the combined action of toxins and hydrolytic enzymes, whose effects on bees have been largely overlooked until recently. Variation in the production of these virulence factors has been observed among strains, even belonging to the same species. Toxigenic and non-toxigenic strains/species may co-exist in a homeostatic equilibrium which is susceptible to be perturbed by several external factors, leading to mutualistic/antagonistic switch in the relationships between Aspergillus and bees.

Aflatoxin Biosynthesis, Genetic Regulation, Toxicity, and Control Strategies: A Review

Aflatoxins (AFs) are highly toxic and cancer-causing compounds, predominantly synthesized by the Aspergillus species. AFs biosynthesis is a lengthy process that requires as minimum as 30 genes grouped inside 75 kilobytes (kB) of gene clusters, which are regulated by specific transcription factors, including aflR, aflS, and some general transcription factors. This paper summarizes the status of research on characterizing structural and regulatory genes associated with AF production and their roles in aflatoxigenic fungi, particularly Aspergillus flavus and A. parasiticus, and enhances the current understanding of AFs that adversely affect humans and animals with a great emphasis on toxicity and preventive methods.

Significance of Apoidea as Main Pollinators. Ecological and Economic Impact and Implications for Human Nutrition

Wild and managed bees provide pollination services to crops and wild plants, as well as a variety of other services beneficial to humans. Honey bees are the most economically valuable pollinator worldwide. It has been calculated that 9.5% of the total economic value of agricultural production comes from insect pollination, thus amounting to just under USD 200 billion globally. More than 100 important crops depend on pollination by honey bees. The latter pollinate not only a wide number of commercial crops but also many wild plants, some of which are threatened by extinction and constitute a valuable genetic resource. Moreover, as pollinators, honey bees play a significant role in every aspect of the ecosystem by facilitating the growth of trees, flowers, and other plants that serve as food and shelter for many large and small creatures. In this paper, we describe how the reduction in honey bee populations affects various economic sectors, as well as human health.