Community structure and antibiotic production of Streptomyces nodosus bioreactors cultured in liquid environments.
Bottom Line: When cell proliferation was encouraged, substrate hyphae were found inside the alginate matrix and within multicellular projections on the surface of the capsule.These organisms sporulated with reduced antibiotic production compared with free-dwelling cultures.The commitment to sporulate was independent of a surface but dependent on community size and nutritional status.
Affiliation: University of Western Sydney, School of Natural Sciences, Parramatta Campus, Locked Bag 1797, Penrith South DC 1797 NSW, Australia.Show MeSH
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Mentions: To determine whether sporulation was dependent on a solid surface, after 48 h of growth 6% (v/v) of a free‐dwelling culture was returned to its own sterilized conditioned medium and cultured for up to 9 days. Confocal laser scanning microscopy revealed extensive sporulation (Fig. 4b) whereas control experiments with unperturbed free‐dwelling populations grown in YMG for 9 days showed no evidence of sporulation (Fig. 4a). To assess whether nutrient limitation was involved in promoting sporulation yeast extract (4 g l−1), malt extract (10 g l−1) and glucose (4 g l−1) were added to 48 h conditioned medium. The returned reduced biomass did not sporulate when cultured for up to 9 days.
Affiliation: University of Western Sydney, School of Natural Sciences, Parramatta Campus, Locked Bag 1797, Penrith South DC 1797 NSW, Australia.