Phytotoxic Strains of Fusarium commune Isolated from Truffles.

Most Fusarium species are known as endophytes and/or phytopathogens of higher plants and have a worldwide distribution. Recently, information discovered with molecular tools has been also published about the presence of these fungi in the microbiome of truffle fruiting bodies. In the present work, we isolated and identified three Fusarium strains from truffle fruiting bodies. All isolates were assigned to the same species, F. commune, and the strains were deposited in the All-Russian Collection of Microorganisms under accession numbers VKM F-5020, VKM F-5021, and VKM F-5022. To check the possible effects of the isolated strains on the plants, the isolates were used to infect sterile seedlings of Sarepta mustard (Brassica juncea L.). This model infection led to a moderate suppression of the photosynthetic apparatus activity and plant growth. Here, we present characteristics of the F. commune isolates: description of the conidial morphology, pigmentation, and composition of the mycelium fatty acids. Overall, this is the first description of the Fusarium cultures isolated from truffle fruiting bodies. Possible symbiosis of the F. commune strains with truffles and their involvement in the cooperative fatty acid production are proposed.

Formation of Azaphilone Pigments and Monasnicotinic Acid by the Fungus Aspergillus cavernicola.

Due to the ever-increasing demand for healthy and safe food, much attention has been gained by natural food colorants. This study showed the culture fluid extract of the fungus Aspergillus cavernicola VKM F-906 to contain red pigment and monasnicotinic acid (MNA) in predominant amounts. The structure of the pigment corresponded to cis-cavernamine (red pigment, RP). Two tautomers, NH and OH forms, in rapid equilibrium were present in a solution of RP. The critical factors for RP to form were the presence of NH4+ salt and pH 6.3-6.5. In vitro experiments showed that MNA was synthesized from RP as a result of chemical transformations without the participation of enzymes. In this case, the main influence on the reaction rate is exerted by the pH of the medium, which is associated with the keto-enol tautomerism of RP in solution. The culture broth extract and MNA exhibited antifungal activity against Fusarium fungi.

Austalides V and W, new meroterpenoids from the fungus Aspergillus ustus and their antitumor activities.

Two new austalide meroterpenoids, named austalides V and W (1 and 2), were isolated from the fungus Aspergillus ustus VKM F-4692. Their structures were elucidated by extensive spectroscopic analysis and by comparison with related known compounds. The main structural feature of both compounds is a tetrahydrofuranyl ring (G), a structural fragment, first found in austalides. Austalides V (1) and W (2) were able to inhibit the propagation of prostate and bladder cancer cells; this biologic activity is possibly related to the inhibition of a number of key pathways regulating cell growth and migration.