Whilst much is known about the development of the complex bacterium Streptomyces coelicolor, the role of membrane heterogeneity in this process has not been investigated. Six genes are thought to be responsible for phospholipid biosynthesis in S. coelicolor, SCO1389, SCO1527, SCO5628, SCO5753, SCO6467 and SCO6468. SCO1389 is predicted to encode a cardiolipin synthase that is an essential gene in this organism. When this gene was placed under the control of an inducible promoter, the strain developed poorly on agar, unless supplemented with the inducer of the promoter. We demonstrated that expression of SCO1389 and PLs became dependent on addition of the inducer to this strain. In order to determine if phospholipids play a role in growth and morphogenesis in S. coelicolor, mRNA from plate grown-cultures was extracted at different developmental stages and analyzed by RT-PCR to detect expression of the phospholipid biosynthetic genes. No amplification products were detected in the absence of mRNA confirming that amplification products are mRNA dependent. Semi-quantitative analysis showed differential expression of these genes at different harvesting times. We also investigated the effect of glucose concentration in both solid and liquid grown YEME cultures in order to discover if this important nutrient source played a role in the determination of the PL content of the membrane. Further studies were carried out on the involvement of PLs in the development of S. coelicolor in strains that carried mutations in bldA and whiD, where this effect was more pronounced. We also investigated the involvement of PLs during development in Streptomyces venezuelae as this organism is able to undergo sporulation in liquid culture and therefore offers the opportunity to isolate large amounts of PLs at different stages of submerged sporulation. Taken together our results demonstrate that there are some changes that take place in the PL profile of streptomycetes during development, but changes in cardiolipin levels appeared to show the greatest fluctuations.
|Award date||17 Feb 2014|
|Place of Publication||Glasgow|
|Publication status||Published - 17 Feb 2014|