Authors: Kamaleshwar P Singh Amit L Mahendra Vibha Jayaraj Pramod P Wangikar Sameer Jadhav
Publish Date: 2012/11/27
Volume: 40, Issue: 2, Pages: 235-244
Abstract
Secondary metabolites such as antibiotics are typically produced by actinomycetes as a response to growth limiting stress conditions Several studies have shown that secondary metabolite production is correlated with changes observed in actinomycete pellet morphology Therefore we investigated the correlation between the production of balhimycin and the spatiotemporal distribution of live and dead cells in pellets of Amycolatopsis balhimycina in submerged cultures To this end we used laser scanning confocal microscopy to analyze pellets from balhimycin producing and nonproducing media containing 02 and 10 g l−1 of potassium dihydrogen phosphate respectively We observed a substantially higher fraction of live cells in pellets from cultures yielding larger amounts of balhimycin Moreover in media that resulted in no balhimycin production the pellets exhibit an initial death phase which commences from the centre of the pellet and extends in the radial direction A second growth phase was observed in these pellets where live mycelia are seen to appear in the dead core of the pellets This secondary growth was absent in pellets from media producing higher amounts of balhimycin These results suggest that distribution of live and dead cells and its correlation with antibiotic production in the nonsporulating A balhimycina differs markedly than that observed in StreptomycetesThe authors gratefully acknowledge Dr Anna Eliasson Lantz for providing A balhimycina DSM 5908 and the balhimycin standard The work was partially supported by grants from the Department of Biotechnology Ministry of Science and Technology Government of India awarded to PPW and the Department of Science and Technology Ministry of Science and Technology Government of India awarded to SJ KPS acknowledges fellowship from University Grants Commission Government of India
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