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Fungi and Water
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Mycotoxins are secondary metabolites produced by microfungi (molds, yeasts) that are capable of causing disease and death in humans and animals. Growth of fungi in human hosts leads to diseases collectively called mycoses, while dietary, respiratory, dermal, and other exposures to toxic fungal metabolites named mycotoxins produce the diseases collectively called mycotoxicosis (125). Mycoses range from merely annoying (e.g., athlete’s foot) to life-threatening (e.g., invasive aspergillosis). The fungi that cause mycoses can be divided into two categories: primary pathogens (e.g., Coccidioides immitis and Histoplasma capsulatum) and opportunistic pathogens (e.g., Aspergillus fumigatus and Candida albicans) (125). In general, primary pathogens affect healthy individuals with normal immune systems, while opportunistic pathogens produce illness in debilitated or immunocompromised hosts – in atopic subjects. The majority of human mycoses are caused by opportunistic fungi (125). In contrast to mycosis, mycotoxicosis is a disease caused by mycotoxins that are toxic compounds present in molds. Mycotoxins are analogous to pesticides or heavy metal residues in foods and can cause disease to everybody (125). The symptoms of a mycotoxicosis depend on the type of mycotoxin; the amount and duration of the exposure; the age, health, and sex of the exposed individual; and many poorly understood synergistic effects involving genetics, dietary status, and interactions with other toxic insults (125).
Trichothecenes
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
I. Malbrán, C.A. Mourelos, J.R. Girotti, G.A. Lori
Mycotoxicoses, the toxic effect of mycotoxins on animal and human health, occur worldwide in both industrialized and developing countries and are illnesses that arise when meteorological conditions that favor the growth of mycotoxigenic fungi combine with social and economic conditions that do not prevent the consumption of contaminated food.4
Introductory Remarks
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
Apart from infections with foodborne viruses, bacteria, fungi, and parasites, another important cause of foodborne diseases is toxins or toxic chemicals produced by foodborne bacteria and fungi as well as those associated with shellfish and plants [6]. Toxins originated from foodborne bacteria can be separated into exotoxins (which remain part of the bacteria, and are secreted, or, similar to endotoxins, released during bacterial lysis) and endotoxins (which form part of the bacterial outer membrane, and are released during bacterial lysis). Some well-known foodborne bacterial exotoxins include superantigens from S. aureus and Streptococcus pyogenes; pore-forming toxins (PFTs) from E. coli, L. monocytogenes, and Streptococcus pneumoniae; heat-stable enterotoxins (ST, exotoxins targeting the intestine) from pathogenic strains of E. coli; and botulinum neurotoxin (BoNT) from C. botulinum. A notable foodborne bacterial endotoxin is lipopolysaccharide (LPS, which is made up of O antigen, core oligosaccharide, and lipid A) from Gram-negative bacteria. As water-soluble proteins, PFTs induce host membrane damages as amphiphilic surfactants and phospholipases. On the other hand, endotoxins (e.g., LPS) cause severe inflammation, endotoxemia (septic shock), and autoimmune disease. Being the by-products of foodborne fungi, mycotoxins are responsible for alimentary mycotoxicoses in humans through food consumption. The most common foodborne mycotoxins consist of aflatoxins (from Aspergillus parasiticus and Aspergillus flavus), altertoxins (from Alternaria), fumonisins (from Fusarium moniliforme), ochratoxins (from Aspergillus ochraceus, Aspergillus carbonarius, Penicillium verrucosum), patulin (from Aspergillus, Penicillium), and trichothecenes (from Fusarium).
Biosensors for the detection of mycotoxins
Published in Toxin Reviews, 2022
Akansha Shrivastava, Rakesh Kumar Sharma
Mycotoxins are low-molecular-weight secondary metabolites produced by filamentous fungi or molds which under suitable and favorable environmental conditions, cause serious risk to human and animal health (Patriarca and Fernández Pinto 2017). These toxins include but not limited to aflatoxins (AFs), ochratoxins (OTs), tremorgenic toxins trichothecenes, fumonisins (F), patulin (P), zearalenone (ZEN), and ergot alkaloids. The classification is done based on their evaluated toxin content by the WHO International Agency of Research on Cancer (WHO-IARC 1993). Aflatoxins were considered as carcinogenic to humans (group 1), while ochratoxins and fumonisins were considered as possible carcinogens (group 2B) and trichothecenes and ZEN as non-carcinogenic to human (group 3). The diseases caused by mycotoxins due to dietary exposure are known as mycotoxicoses. Many mycotoxins are potent in low doses and a small amount can cause significant health effects. Mycotoxins may be involved in cancer and other disorders including gastrointestinal, urogenital, vascular, renal, respiratory, and nervous systems (Bennett and Moore 2019). The growth of fungus changes the physical and chemical composition of the food and foodstuffs. These changes can often be used advantageously to distinguish fungal infected food materials.
Mycotoxicosis – diagnosis, prevention and control: past practices and future perspectives
Published in Toxin Reviews, 2020
Some mycotoxins produce lesions that allow a definitive diagnosis like zearalenone, yet a much larger number of mycotoxins produce lesions that do not permit a definitive diagnosis like aflatoxins, ochratoxins, trichothecenes, patulin, tremorgenic mycotoxins, moniliformin, citreoviridin, and so on. The clinical findings and pathological lesions in such cases are highly suggestive of the presence of mycotoxicosis but epidemiological or analytical findings are necessary for confirmed diagnosis. Table 1 shows some of the specific and generalized lesions caused by different mycotoxins.
Novel avenues for identification of new antifungal drugs and current challenges
Published in Expert Opinion on Drug Discovery, 2022
Mycotoxins (secondary toxic metabolites of fungi) are mainly excreted by Aspergillus sp. (A. flavus, A. parasiticus, A. ochraceus, A. carbonarius, A. oryzae), Penicillium sp. (P. citrinum, P. camemberti, P. expansum), Fusarium sp., Alternaria sp., C. albicans, Stachybotrys chartarum, Blastomyces dermatitidis, and Paracoccidioides brasiliensis and contaminate fruits, vegetables, cereals, legumes, nuts, etc., creating a serious threat to human and animal health around the world [22,23]. According to statistics, prior to 1985, approx. 25% of world crop production was affected by mycotoxins, while in 2015, almost 75% of crops were contaminated worldwide. In the last 10 years, mycotoxins have accounted for 30–60% of food and feed rejections at the European Union’s borders [23–26]. This extreme increase is due to climate change, including increases in average global air temperatures and changes in rainfall distribution, but especially increased weather variability with more extreme events, resulting in shifts in fungal populations and increased crop contamination by mycotoxins. Drought conditions are a stress factor that makes plants susceptible to fungal infection and leads to increased production of mycotoxins. Some fungi produce more than one mycotoxin, and some mycotoxins are produced by more than one fungal species. Diseases caused by ingestion or inhalation of or dermal exposure to mycotoxins contaminating agricultural commodities before or after harvest are known as mycotoxicosis. Mycotoxins alone are estimated to cause 3.2 million cases and 50,000 hospitalizations per year in the EU. The most important and common mycotoxins are aflatoxins (B1, B2, G1, G2), ochratoxin (A, B, C), citrinin, ergot alkaloids, patulin, zearalenone, trichothecenes, fumonisins, beauvercin, enniatins, butenolide, equisetine, and candysarins. They are carcinogenic, hepatotoxic, nephrotoxic, and damaging the epithelial, immune, and nervous systems [22,23].