[Learning from Natural Products: Study on Actinomycetes of the Genus Nocardia]

The genus Nocardia comprises gram-positive bacteria, most of which are pathogenic and cause opportunistic infections of the lungs, skin, and brain in humans. Based on a collaboration study with the Medical Mycology Research Center, Chiba University, we focused on Nocardia actinomycetes as a new natural-product resource. First, by culturing (monoculture) Nocardia in various media, we isolated a new aminocyclitol nabscessin A from Nocardia abscessus IFM10029^T and a new γ-lactone inohanalactone from Nocardia inohanaensis IFM0092^T. On the other hand, by imitating the state in which the genus Nocardia actinomycete infects animal cells and culturing the genus in the presence of animal cells (coculture), this genus was expected to produce new compounds through interactions with the animal cells. Using mouse macrophage-like cells (J774.1) as animal cells, a new pantothenic acid amide derivative and a cyclic peptide, nocarjamide, with Wnt signal activation activity were isolated from Nocardia tenerifensis IFM10554^T strain.