Sporulation of Streptomyces griseus in submerged culture

Abstract

A wild-type strain of Streptomyces griseus forms spores both on solid media (aerial spores) and in liquid culture (submerged spores). Both spore types are highly resistant to sonication, but only aerial spores are resistant to lysozyme digestion. Electron micrographs suggest that lysozyme sensitivity may result from the thinner walls of the submerged spores. Studies of the life cycle indicate that neither streptomycin excretion nor extracellular protease activity is required for sporulation; the analysis of mutants, however, suggests that antibiotic production may be correlated with the ability to sporulate. A method was devised to induce the rapid sporulation of S. griseus in a submerged culture. This method, which depends on nutrient deprivation, was used to determine that either ammonia or phosphate starvation can trigger sporulation and that the enzyme glutamine synthetase may be useful as a sporulation marker after phosphate deprivation.The life cycle of streptomycetes is unique among bacteria. Under appropriate culture conditions, a single spore germinates, grows vegetatively as a substrate (primary) mycelium, and ultimately segments into chains of spores. The developing spores are typically enveloped by a sheath (3). The thick-walled spores are physiologically dormant when mature and are relatively resistant to lytic enzymes, low temperature, and osmotic extremes (3).The sporulation process has been well documented with respect to the ultrastructure of cultures grown on solid media (5,9,17,22). Physiological studies have been hampered by the inability to obtain uniform sporulation of the organism in a liquid culture. We have observed, however, that some streptomycetes can be induced to sporulate in a liquid culture when critical nutritional and environmental conditions are met. In this paper, we report the results of experiments conducted with a wild-type strain of Streptomyces griseus, which sporulates well when cultivated in liquid media. A method for the induction of rapid sporulation is described and used to characterize the physiology of sporulation with respect to nutritional requirements, enzyme behavior, and time course of differentiation. METHODSOrganisms and growth conditions. Table 1 lists the strains used in this study. The strains were maintained on slants of medium A composed of casein hydrolysate (1 g/liter), yeast extract (5 g/liter), NaCl (5 g/liter), t Present address:

Production of dihydroabikoviromycin by Streptomyces anulatus: production parameters and chemical characterization of genotoxicity

“…It can be concluded that S. anulatus JH801 is among the few Streptomyces strains that sporulate in submerged cultures (the first Streptomyces strain to show submerged sporulation, S. griseus, was found by Kendrick and Ensign (1990)). In general, Streptomyces strains sporulate relatively easily on solid media, with no special medium requirements reported (Glazebrook et al 1990).…”

Pre-sporulation stages ofStreptomycesdifferentiation: state-of-the-art and future perspectives

“…Secondary metabolites would be produced by the substrate mycelium at the stationary phase after a transient growth arrest (Granozzi et al, 1990;Neumann et al, 1996;Novotna et al, 2003;Zhou et al, 2005;Chouayekh et al, 2007). Despite that, sporulation was reported in liquid cultures for several streptomycetes, such as Streptomyces venezuelae (Glazebrook et al, 1990), S. griseus (Kendrick & Ensign, 1983), Streptomyces chrysomallus (Kuimova & Soina, 1981), S. antibioticus ETHZ7451 (Novella et al, 1992), Streptomyces albidoflavus SMF301 (Rho & Lee, 1994), or Streptomyces brasiliensis (Rueda et al, 2001). Sporulation was also seen to be activated in several Streptomyces species under nutritional downshifts, including the model strain S. coelicolor (Koepsel & Ensign, 1984;Daza et al, 1989), and was also observed in several streptomycetes liquid cultures during the screening experiments aimed at discovering novel secondary metabolites (Yag€ ue P, Genilloud O, Manteca A, unpublished results).…”

Members of the IclR family of bacterial transcriptional regulators function as activators and/or repressors

“…Streptomycetes are aerobic gram-positive soil bacteria that grow as multinucleoidal, multicellular, branched filaments and undergo morphological and physiological differentiation in response to environmental factors (Kendrick & Ensign, 1983;Champness & Chater, 1994;Chater, 1998;Keijser et al, 2002). The first sign of morphological differentiation is the formation of aerial sporogenic hyphae, which give a fuzzy, white appearance to the colonies.…”