Polyphasic identification and preservation of fungal diversity : concepts and applications

Fungi are a diverse group of unique eukaryotic organisms currently accepted as the Eumycota kingdom. The (under) estimated number of fungal species is 1.5 × 106 of which only a small number have been identified (ca. 8–10%). They are ubiquitous in nature with an extraordinary ability to decompose plant wastes while also causing much spoilage of food and other relevant commodities. Certain species are used directly as food and others in the manufacture of foodstuffs, antibiotics, enzymes, organic acids and alcohol. Still others can infect humans, animals and crops. Information about each microorganism (e.g. morphological and molecular descriptions, including modern spectral data – MALDI-TOF MS, physiological and biochemical features, ecological roles, and societal risks or benefits) is the key element in fungal identification. In order to attain a sound fungal identification a polyphasic approach is required. It is achieved through the integration of all biological traits data. Fungal service culture collections have well established management systems and preservation techniques that are of elemental importance and guarantee the proper identification and characterisation of environmental fungal isolates. They also assure the continuity of taxonomic and comparative studies and fungal availability for biotechnological exploitation. To foster bio-economy and sustain the biotechnological developments new demands for quality control of fungal holdings preserved in culture collections are in course. The quality control system is associated with new guidelines for the culture collections to operate at global level and to adapt the traditional fungal repositories into the new OECD concept of Biological Resource Centres (BRCs).(undefined

Microbial metabolites as molecular mediators of host-microbe symbiosis in colorectal cancer

The symbiosis between the gut microbiota and the host has been identified as an integral part of normal human physiology and physiological development. Research in germ-free or gnotobiotic animals has demonstrated the importance of this symbiosis in immune, vascular, hepatic, respiratory and metabolic systems. Disruption of the microbiota can also contribute to disease, and the microbiota has been implicated in numerous intestinal and extra-intestinal pathologies including colorectal cancer. Interactions between host and microbiota can occur either directly or indirectly, via microbial-derived metabolites. In this chapter, we focus on two major products of microbial metabolism, short-chain fatty acids and bile acids, and their role in colorectal cancer. Short-chain fatty acids are the products of microbial fermentation of complex carbohydrates and confer protection against cancer risk, while bile acids are compounds which are endogenous to the host, but undergo microbial modification in the large intestine leading to alterations in their bioactivity. Lastly, we discuss the ability of microbial modulation to mediate cancer risk and the potential to harness this ability as a prophylactic or therapeutic treatment in colorectal cancer