Mycotoxins from Mold Fungi — Weapons of Uninivited Fellow‐Boarders of Man and Animal: Structures, Biological Activity, Biosynthesis, and Precautions

Abstract

In addition to the antibiotics, mycotoxins represent a second large group of biologically active substances of microbial origin. Over 300 mycotoxins are so far known and can be subdivided into 25 structural types. They are formed by approximately 350 molds of which there are 10000 different strains. As mycotoxin-producing molds tend to spread aggressively on foodstuffs, they can cause epidemic mycotoxicoses.-The mycotoxins have been isolated, their structures determined, and their biological activities investigated; their biosynthesis has now also largely been elucidated. Accordingly, mycotoxins are derived from only three groups of key biogenetic building blocks: polyketides, isopentenyl pyrophosphate, and amino acids. Mycotoxins are mainly non-polar, chemically stable, are formed in high concentrations, and do not contain-unlike antibiotics-any sugars. Mycotoxins display an enormous variety of toxic-pharmacological activities, e.g. liver degradation, hemorrhages, carcinomas. The identification of mycotoxicoses is impeded by their long incubation periods and the fact that the mycotoxins tend to accumulate in the mammalian organism, which means that even very low concentrations in food are a potential danger. The particularly dangerous aflatoxin B1 1 may not exceed a limit in food of 5 ppb (5 pg/kg), which is difficult to control. IntroductionEveryone knows what happens when fruit juice is left to stand unprotected for a few days (Fig. 1). Mold colonies are formed from the germs present in the air, usually Aspergillus and Penicillium species. We then do not feel like drinking the juice, our instinct warns us to be careful, and this is important because many of these fungi produce poisonous metabolic products which are dangerous for man and mammals. These poisonous substances are called mycotoxins.The biological activities of the mycotoxins differ from those of the antibiotics produced against bacteria. The mycotoxins and antibiotics provide the microorganisms with effective means of driving other living organisms away Lecture given at the Universitat Gottingen.[**I Extended and supplemented version of an Adolf Windaus Memorial from their sources of food. In Figure 1 the molds have already won this battle, as man can now no longer enjoy the foodstuff they have covered. Some typical features of mycotoxins and antibiotics are compiled in Table 1. Mycotoxins are synthesized by the rapidly growing, aggressively spreading molds; antibiotics are mostly formed by Streptomycetes. Whereas the Streptomycetes are satisfied with residual substances such as cellulose and chitin, which are difficult to degrade, molds compete with higher organisms for their foodstuffs and fodder. Man and mammals are thus greatly endangered by my cot oxins.Penicillin G and streptomycin are the most important antibiotics, whilst aflatoxin B, 1 is the most dangerous representative of the mycotoxins.The danger posed by the mycotoxins and the diseases they cause, mycotoxicoses, were underestimated for a long time, which is why they are also referred ...

Production of toxic metabolites in Aspergillus niger, Aspergillus oryzae, and Trichoderma reesei: justification of mycotoxin testing in food grade enzyme preparations derived from the three fungi

“…Despite the knowledge of the biosynthesis of several mycotoxins (Franck, 1984), the pathways and regulations for the biosynthesis of many mycotoxins are yet to be elucidated. The Environmental Protection Agency (EPA, 1997a) evaluated the safety of A. niger and concluded that ''mycotoxin production appears to be controlled by the conditions of fermentation'' and be strain specific.…”

Solid-phase synthesis and biological activity of malformin C and its derivatives

“…Malformins, produced from Aspergillus niger, are a group of cyclic pentapeptides with a disulfide bond formed from two cysteine thiols. The compounds express various biological activities, such as inducing root curvatures and malformations in plants, [1][2][3][4] antibacterial activity against Gram-positive and Gram-negative bacteria, [5][6][7] enhanced fibrinolytic activity 8 and inhibitory activity of the G 2 checkpoint. 9 Owing to their unique structures and diverse biological profiles, several processes for the synthesis of malformins have been examined.…”

Rhizonin, the First Mycotoxin Isolated from the Zygomycota, Is Not a Fungal Metabolite but Is Produced by Bacterial Endosymbionts

“…Even so, the identification of mycotoxins responsible for mass intoxification of animals and humans was an epoch-making discovery in the last century (3). The epidemic Turkey "X" disease and the historical and modern cases of ergotism (St. Anthony's Fire) are infamous examples of mycotoxicoses, underscoring the global impact of food spoilage by fungi (3). Even low concentrations of mycotoxins in food can elicit deleterious effects such as chronic or acute toxic damage of liver and kidney.…”