Biodiversity, evolution and adaptation of fungi in extreme environments

Fungi play irreplaceable roles for ecosystem functioning. They may adopt different lifestyles, for example saprotrophs, symbionts or parasites: some species are cosmopolitan with a wide distribution and others, thanks to their ecological plasticity, may adapt to harsh environments precluded to most of life forms. In stressing conditions, their role is even more crucial for the recycling of organic matter or favoring nutrients uptake. When the conditions become really extreme and competition is low, fungi focus on extremotolerance and evolve peculiar competences to exploit natural or xenobiotic resources in the particular constrains imposed by the environment. This paper focuses on three different cases of fungal life in the extremes: hydrocarbon-polluted sites, extremely acidic substrates, and littoral dunes, aiming to give few but significant examples of the role of these fascinating organisms in peculiar habitats and the valuable biotechnological potentialities of the abilities they have evolved in response to such constrains

Flow cytometry as a tool to investigate nuclear senescence in symbiotic and pathogenic systems

Arbuscular mycorrhizae have been reported to moderate negative effects (growth inhibition, necrosis, death) caused by soil-borne pathogenic fungi. In this paper, we assessed root viability with two DNA fluorescent flow cytometry stains that can be usefully combined to evaluate chromatin changes. Nuclei were extracted from arbuscular mycorrhizal (Glomus mosseae) and non-mycorrhizal tomato roots, infected or uninfected with Phytophthora nicotianae var parasitica and watered with a low phosphate nutrient solution. Nuclei extracted from non-mycorrhizal roots infected with the pathogenic fungus showed lower fluorescence values after staining, compared to arbuscular mycorrhizal roots, suggesting that the presence of the pathogen may result in DNA loss and condensation. Infection by either fungus (symbiotic and pathogen) reduced the ratio of 4c to 2c nuclei in the differentiated root.La cytométrie de flux comme moyen pour étudier la sénescence nucléaire dans des systèmes symbiotiques et pathogènes. Les mycorhizes arbusculaires sont connues pour réduire les effets négatifs (croissance, nécrose, mort) causés par les pathogènes telluriques. Dans ce travail, nous avons évalué par cytométrie de flux, la viabilité des racines, en utilisant deux colorants d'ADN qui, en combinaison, permettent d'estimer les changements au niveau de la chromatine. Les noyaux ont été extraits des racines de tomate mycorhizées ou non avec Glomus mosseae ou infectées ou non avec Phytophthora nicotiana var parasitica et ayant reçu une solution nutritive pauvre en phosphore. Les noyaux extraits des racines non mycorhizées, infectées avec le champignon pathogène, ont donné des valeurs plus faibles de florescence par rapport à ceux obtenus avec des noyaux extraits des racines mycorhizées. Cela suggère que la présence de champignons pathogènes se traduit au niveau de l'ADN par une perte de condensation. L'infection par les deux champignons (symbiotique et pathogène) réduit le rapport du nombre de noyaux 4c par rapport aux 2c dans les racines différenciées

The Golden touch – Fungal bioconversion of agroindustrial waste in high value compounds

Reuse what you can, recycle what cannot be reused, repair what is broken, remanufacture what cannot be repaired1. These are the main pillars of the circular economy system. In spite of a linear economy system, these sustainable processes would turn goods that are at the end of their service life into resources for others. This is the way to close loops in industrial ecosystems and minimize waste, a concept that should soon disappear. Is it feasible? Microbial biodiversity could help to change the fate of agroindustrial wastes, transforming them in new products. Thanks to their natural capability to grow on cellulose and lignin, fungi could be good candidates. Fungal fermentation is independent from land exploitation, being ethical sustainable by not competing with food and farm industry. In the optimal conditions, fungal growth could be economic and energetic sustainable, as required by the principle of the green economy. Within the Fungal Kingdom, a great variety of fungal features and metabolic pathways could be found. Unfortunately, this metabolic richness is still poorly known. Moreover, several fungi are edible, and some have a good nutritional quality, being rich in protein, polysaccharides, with low rate of fatty acids, high PUFA levels, and other nutritional compounds as vitamins and essential amino acids. Basidiomycetes and Ascomycetes have been used for centuries as folk medicines, especially in Asian countries, where their medicinal properties are well known. The immunomodulatory and antitumoral properties of substances extracted from various species of edible mushrooms are now also extensively recognized at a scientific level. This project was aimed to investigate the methods to produce such a high-value biomass with low economic and environmental impact. In particular, this work was aimed to find fungal strains which could grow on agroindustrial waste, as for example food industry or insect breeding wastes. These wastes could then find a new exploitation to have good biomass yields, with the desired nutritional features. In this work, medicinal mushrooms have been selected, including Pleurotus ostreatus and Ganoderma lucidum, both known to metabolise many kinds of substrates and to contain a wide variety of bioactive components. To investigate their ability to metabolise agroindustrial wastes and transform them in high value products, media composition was designed using not-easily accessible C and N sources. Twenty cultural lines were set up in submerged fermentation using different wastes. The first goal was to evaluate how biomass production yields were affected by different C and N sources and their ratio. Preliminary results about the biomass recovery and the fungal ability to metabolise agroindustrial wastes look very promising. More in details, fungal strains were able to grow in the presence of most of the media and, in particular, in the presence of insect breeding wastes where the biomass recovery was comparable to the control. Additional efforts are now focused to study the fungal broths and the biomass extracts. They will be analysed from a nutraceutical point of view, evaluating also their antioxidant and radical scavenging properties using spettrophotometric assays. For instance, Folin-Ciocalteu test, ABTS and DPPH assays will be used to assess the presence of bioactive molecules that could a positive outcome on animal and human health

Solution-Phase Parallel Synthesis of Aryloxyimino Amides via a Novel Multicomponent Reaction among Aromatic (Z)-Chlorooximes, lsocyanides, and Electron-Deficient Phenols

A library of 41 aryloxyimino amides was prepared via solution phase parallel synthesis by extending the multicomponent reaction of (Z)-chlorooximes and isocyanides to the use of electron-deficient phenols. The resulting aryloxyiminoamide derivatives can be used as intermediates for the synthesis of benzo[d]isoxazole-3-carboxamides, dramatically reducing the number of synthetic steps required by other methods reported in literature