Streptomyces bacteria form colonies that contain several different types of specialized cells: vegetative hyphae, aerial hyphae, spores and the "explorer" cells discovered by Jones et al. (A) A Streptomyces coelicolor colony exhibiting aerial hyphae (white) and spores (gray). The blue droplets contain compounds that are naturally produced by S. coelicolor including antibiotics. (B) Streptomyces venezuelae explorer cells spreading on a rock. (C) In addition to these four types of cells, it is possible that Streptomyces colonies might contain other cell types that produce specialized metabolites, such as antibiotics, signaling molecules or volatile organic compounds (VOCs).
Image credits: panel A and C Vineetha Zacharia; panel B Jones et al. (2016)