Bovistol B, bovistol D and strossmayerin: Sesquiterpene metabolites from the culture filtrate of the basidiomycete Coprinopsis strossmayeri

Beyond Penicillin: The Potential of Filamentous Fungi for Drug Discovery in the Age of Antibiotic Resistance

Antibiotics are a staple in current medicine for the therapy of infectious diseases. However, their extensive use and misuse, combined with the high adaptability of bacteria, has dangerously increased the incidence of multi-drug-resistant (MDR) bacteria. This makes the treatment of infections challenging, especially when MDR bacteria form biofilms. The most recent antibiotics entering the market have very similar modes of action to the existing ones, so bacteria rapidly catch up to those as well. As such, it is very important to adopt effective measures to avoid the development of antibiotic resistance by pathogenic bacteria, but also to perform bioprospecting of new molecules from diverse sources to expand the arsenal of drugs that are available to fight these infectious bacteria. Filamentous fungi have a large and vastly unexplored secondary metabolome and are rich in bioactive molecules that can be potential novel antimicrobial drugs. Their production can be challenging, as the associated biosynthetic pathways may not be active under standard culture conditions. New techniques involving metabolic and genetic engineering can help boost antibiotic production. This study aims to review the bioprospection of fungi to produce new drugs to face the growing problem of MDR bacteria and biofilm-associated infections.

Identification of volatile producing enzymes in higher fungi: Combining analytical and bioinformatic methods

Filamentous fungi harbor the genetic potential for the biosynthesis of several secondary metabolites including various volatile organic compounds (VOCs). Nonetheless, under standard laboratory conditions, many of these VOCs are not formed. Furthermore, little is known about enzymes involved in the production of fungal VOCs. To tap these interesting topics, we developed an approach to identify enzymes putatively involved in the fungal VOC biosynthesis. In this chapter, we highlight different fungal cultivation methods and techniques for the extraction of VOCs, including a method that allows the noninvasive analysis of VOCs. In addition using terpene synthases as an example, it is depicted how enzymes putatively involved in VOC synthesis can be identified by means of bioinformatic approaches. Transcriptomic data of chosen genes combined with volatilome data obtained during different developmental stages is demonstrated as a powerful tool to identify enzymes putatively involved in fungal VOC biosynthesis. Especially with regard to subsequent enzyme characterization, this procedure is a target-oriented way to save time and efforts by considering only the most important enzymes.

Illudane Sesquiterpenoids from Edible Mushroom Agrocybe salicacola and Their Bioactivities

To comprehensively understand the chemical constituents of the edible mushroom Agrocybe salicacola and their biological functions, a phytochemical separation of the cultural broth of A. salicacola led to the isolation of four new illudane sesquiterpenoids, agrocybins H-K (1-4), along with 10 known analogues (5-14). Compounds 2-4 were racemates of which 2 and 3 were further separated into single enantiomers as 2a/2b and 3a/3b. All new structures with absolute configurations were elucidated on the basis of an extensive spectroscopic analysis and quantum chemistry calculations. Compound 1 possesses a new carbon skeleton that might be derived from the protoilludane backbone. Compounds 1, 5, 8, and 9 show a certain degree of cytotoxicity to five human cancer cell lines. Compound 1 shows a mild inhibitory effect on nitric oxide production with an IC₅₀ value of 31.4 μM. It is concluded that A. salicacola is rich in illudin derivatives with potential bioactivity prospects, which would make A. salicacola a good material of medicine and food homology.