The global transcriptional effect of exogenously added butyrolactone I on Aspergillus terreus under submerged culture

The filamentous fungus Aspergillus terreus is known to produce both industrially and pharmaceutically important secondary metabolites. The objective of this study is to investigate the effect of exogenously added butyrolactone I (BI) on the submerged culture of A. terreus, especially on the possible regulation of the secondary metabolism on the transcriptional level. In order to elucidate the presumed regulative role of butyrolactone I, a large-scale microarray gene expression study was designed and conducted with an industrially utilised A. terreus strain MUCL38669. A. terreus MUCL38669 was cultured in secondary metabolism inducing submerged conditions for nine days, where butyrolactone I was added at the beginning of the growth phase (at 24 hours p.i.), in the middle of the growth phase (at 96 hours p.i.) or in the late growth phase (at 120 hours p.i.), in addition to the control culture where no exogenous butyrolactone I was added. To obtain comprehensive gene expression profiles over the whole culture time, samples were taken at six time points: 24 hours, 48 hours, 96 hours, 120 hours, 144 hours and 216 hours post inoculation. This study is composed of three treated A. terreus strain MUCL38669 submerged cultures where butyrolactone I (BI) was exogenously added at the following time points: 24 hours, 96 hours and 120 hours post inoculation, and one control culture where no BI was added. All these four submerged culture sets were incubated simultaneously in three biological replicates. The samples to be analysed were taken at 24 hours, 48 hours, 96 hours, 120 hours, 144 hours and 216 hours post inoculation. This generates the 72 samples to be analysed in total.The available A. terreus NIH2624 genome was utilised in the custom probe design.