Project description:Advanced clinical trials investigate the Psilocybe magic mushroom natural product psilocybin as a treatment against major depressive disorder. Currently, synthetic material is used to meet the demand for legitimate pharmaceutical purposes. Here, we report an in vitro approach to biocatalytically produce psilocybin on a solid-phase matrix charged with five covalently bound biosynthetic enzymes. These enzymes include three Psilocybe enzymes: IasA, an engineered L-tryptophan decarboxylase/aromatic aldehyde synthase, the 4-hydroxytryptamine kinase PsiK and the norbaeocystin methyltransferase PsiM, along with Escherichia coli nucleosidase MtnN and adenine deaminase Ade. In a proof-of-principle experiment, this enzyme-charged resin allowed for quantitative turnover of 4-hydroxy-L-tryptophan into psilocybin. This facile process i) represents a sustainable approach with reusable enzymes, ii) circumvents the drawbacks of in vivo processes while harnessing the selectivity of enzymatic catalysis and iii) helps access an urgently needed drug candidate.
Project description:The human fungal pathogen Candida albicans can switch stochastically and heritably between a “white” phase and an “opaque” phase. Opaque cells are the mating-competent form of the species whereas white cells are essentially “sterile”. Here, we report that glucose depletion, a common nutrient stress, enables C. albicans white cells to undergo efficient sexual mating. The relative expression levels of pheromone-sensing and mating-associated genes (including STE2/3, MFA1, MFalpha1, FIG1, FUS1, and CEK1/2) were increased under glucose depletion conditions, while expression of mating repressors TEC1 and DIG1 was decreased. We show that Cph1 and Tec1, factors that act downstream of the pheromone MAPK pathway, play opposite roles in regulating white cell mating as TEC1 deletion or CPH1 overexpression promoted white cell mating. Moreover, inactivation of the Cph1 repressor Dig1 increased white cell mating ~4,000 fold in glucose-depleted medium relative to that in the presence of glucose. These findings reveal that the white-to-opaque epigenetic switch may not be a prerequisite for sexual mating in C. albicans in nature. Given parallels between C. albicans white cell mating to that of other yeast species, this mechanism of mating could represent a more ancient strategy of sexual reproduction in C. albicans.