Biomimicry in action: Using furanones to address diseases and fouling issues in marine aquaculture

Aquaculture is the fastest growing food production sector worldwide. However, the development of this industry is limited by the outbreak of diseases, which occur on account of the abuse of antibiotics in order to keep the spreading of infections under control. This has led to the global problem of antimicrobial resistant genes, which constitutes a major threat to human and animal health, and to the natural environment. The red marine alga Delisea pulchra has evolved a defense mechanism to protect itself from extensive bacterial colonization, specifically by causing a disruption of the key quorum sensing (QS), bacterial cell-to-cell communication, which in turn controls the virulence factor of pathogens, through the exudation of halogenated furanones. A biomimicry solution to avoid a priori use of conventional antibiotics would be to produce those secondary metabolites synthetically and employ them as a potential anti-virulence therapy and anti-fouling strategy. The main advantage of this ‘biomimetic’ approach is that there will be none, or minimum interference with non-target organisms. Many findings confirm that the use of furanones was successful both in-vitro and in-vivo to protect fish and crustaceans from pathogens. In addition, furanones are effective when incorporated into polymers designed to prevent macrofouling by epiphytic algae, barnacles and bryozoans on sea-cages, and to prevent corrosion. In conclusion, this sustainable biomimetic approach promises a safer alternative to conventional antibiotics, providing a broad range of applications in marine fields, preventing bacteria resistance and minimizing negative impacts in marine environment

The effect of mushroom culture filtrates on the inhibition of mycotoxins produced by Aspergillus flavus and Aspergillus carbonarius

Two of the mycotoxins of greatest agroeconomic significance are aflatoxin B-1 (AFB(1)), and ochratoxin A (OTA). It has been reported that extracts from some wood-decaying mushrooms, such as Lentinula edodes and Trametes versicolor showed the ability to inhibit AFB(1) or OTA biosynthesis. Therefore, in our study, a wide screening of 42 isolates of different ligninolytic mushrooms was assayed for their ability to inhibit the synthesis of OTA in Aspergillus carbonarius and AFB(1) in Aspergillus flavus, in order to find a metabolite that can simultaneously inhibit both mycotoxins. The results showed that four isolates produce metabolites able to inhibit the synthesis of OTA, and 11 isolates produced metabolites that inhibited AFB(1) by >50%. Two strains, the Trametes versicolor strain TV117 and the Schizophyllum commune strain S.C. Ailanto, produced metabolites able to significantly inhibit (>90%) the synthesis of both mycotoxins. Preliminary results suggest that the mechanism of efficacy of the S. commune rough and semipurified polysaccharides could be analogous to that found previously for Tramesan(R), by enhancing the antioxidant response in the target fungal cells. The overall results indicate that S. commune's polysaccharide(s) could be a potential agent(s) in biological control and/or a useful component of the integrated strategies able to control mycotoxin synthesis