Submerged culturing of mycelium is an efficient technique used to increase biomass yields, more so when employed with naturally slow-growing species of mushrooms. This paper is concerned with optimizing nutrient broth components used in Inonotus obliquus cultures for achieving high biomass yields. We modeled the effect of seven biotechnological parameters (six broth ingredients and the initial pH of nutritive broth) on mycelial biomass and predicted an optimum broth formula using response surface methodology. An analysis of variance showed that the elaborated model is significant (F-value of 2.76 and p-value of 0.0316). We used bioreactor cultures to confirm the model’s optimum prediction and to compare these results with a general-purpose mycology medium, namely potato dextrose broth (PDB). The optimized bioreactor culture yielded 4.37 g/L (93.36% of the dry weight prediction), while the PDB bioreactor culture yielded 2.084 g/L, after 15 days of cultivation. The optimized formula was: 2.15299 g malt extract, 3.99296 g yeast extract, 11.0041 g fructose, 17.4 g soluble starch, 0.1 g MgSO₄, and 0.05 g CaCl₂ per liter of broth.

Inonotus obliquus is a parasite on the birch and other trees and is also a well-known medicinal mushroom. Its sterile conk is highly sought for its bioactive compounds such as phenols, polysaccharides, triterpenoids, and steroids. It was traditionally used to treat various gastrointestinal diseases, viral and parasitic infections, to counteract the progression of cancers, and to stimulate the immune system. We used acute gamma irradiation, followed by short-term submerged cultivation, as an oxidative stress inducer to enhance the synthesis of mycelial metabolites. The 300 Gy and 400 Gy doses showed the best results across the whole experimental design. Each assayed criterion had a different corresponding optimal stimulation dose. In one experiment, sublethal doses of irradiation triggered the dry weight of the cultured mycelium to increase by 19.764%. The free radical scavenging potential of the mycelium extracts increased by 79.83%. The total phenolic content of mycelium extracts and culture broth increased by 55.7% and 62.987%, respectively. The total flavonoid and sinapinic acid content of the broth increased by 934.678% and 590.395%, respectively. As such, gamma irradiation pre-treatment of the mycelial inoculum proved an interesting, economically and environmentally effective tool for stimulating secondary metabolite synthesis in submerged mycelium cultures.

The rabies virus is a major zoonosis that causes severe nervous disease in humans, leading to paralysis and death. The world’s second anti-rabies center was established in 1888 by Victor Babeș, in Bucharest, where an eponymous strain of rabies was isolated and used to develop a method for immunization. The Babeș strain of the rabies virus was used for over 100 years in Romania to produce a rabies vaccine for human use, based on animal nerve tissue, thus having a proven history of prophylactic use. The present study aimed to sequence the whole genome of the Babeș strain and to explore its genetic relationships with other vaccine strains as well as to characterize its relevant molecular traits. After being adapted for multiplication in cell lines and designated BAB-TMP, 99% of the viral genome was sequenced. The overall organization of the genome is similar to that of other rabies vaccine strains. Phylogenetic analysis indicated that the BAB-TMP strain is closely related to the Russian RV-97 vaccine strain, and both seem to have a common ancestor. The nucleoprotein gene of the investigated genome was the most conserved, and the glycoprotein showed several unique amino acid substitutions within the major antigenic sites and linear epitopes.