Impact of desiccation on the global transcription of Acinetobacter baumannii AB5075
We perform RNA-seq comparing A. baumannii AB5075 cells resuspended in water or diluted M9-succinate and desiccated during 24 h (relative humidity 8-12%) to cells resuspended in water before desiccation. A. baumannii AB5075 cultures (3 independent biological replicates) were grown overnight (approx. 16 h) in M9 minimal medium supplemented with Na-succinate 20 mM. Cultures were split in two and each half was washed 3 times either with distilled water or with M9-succinate 20 mM diluted 1:250 (v:v). OD600 of the cell supensions was adjusted to 1.0 and 1 ml from the water-suspended cells was withdrawn as a control comparison, washed with RNAlater and stored at -80 C until further processing. 1 ml of the OD-adjusted water- and M9-suspended cells were spotted on polystyrene Petri dishes and left to air-dry in a laminar flow hood. Once dried, the plates were placed in a chamber with Drierite until reaching a relative humidity of 8-12% and were incubated during 24 h. Finally, cells were harvested by directly resspending them in RNAlater and stored at -80 C. After that, total RNA was extracted from each sample and cDNA libraries were generated and sequenced. The different comparisons showed that: i) 309 and 279 genes were upregulated and downregulated, respectively, in cells ressupended in water and desiccated compared to the control; ii) 435 and 512 genes were upregulated and downregulated, respectively, in cells resuspended in diluted M9-succinate and desiccated compared to the control; iii) 327 and 242 genes were upregulated and downregulated, respectively, in the cells resupended in water and desiccated compared to the cells resuspended in diluted M9-succinate and desiccated. Overall design: Three independent replicates of A. baumannii AB5075 were grown overnight in M9 minimal medium supplemented with Na-succinate 20 mM, split in two equal volumes, washed 3 times with either distilled water or M9-succinate diluted 1:250 (v:v) and the OD600 was adjusted to 1.0. Then, 1 ml of each sample was spotted on a Petri dish and was left to air-dry. When dry, the Petri dishes were placed in a chanber with 8-12% relative humidity and were icubated for 24 h. 1 ml of the water suspended cells were withdrawn as control condition.