SRA

Leptospirillum ferriphilum is an important acidophilic ferrous iron-oxidizing species for bioleaching or biooxidation to win metals like copper or gold, respectively. L. ferriphilum is inhibited by elevated conentrations of chloride. In the present study, the type strain of L. ferriphilum (i.e. strain DSM 14647) by subcultivation in presence of increasing chloride concentrations was adapted to tolerate higher concentrations of NaCl. The adapted culture was grown in presence of 180 mM NaCl or and the non-adapted culture without NaCl, and both were harvested in the late exponential phase. Total RNA was isolated and checked for quality and integrity. For each of the two conditions three RNA preparations of high quality (integrity number above 7) were pooled. Ribosomal RNA was depleted. DNA libraries for paired-end sequencing on an Illumina MiSeq were generated with a TruSeq stranded mRNA library prep kit (Illumina). Among the genes up-regulated were those coding for proteins likely involved in intracellular pH regulation, response to reactive oxygen species, and Fe-S cluster biosynthesis. Among the genes down-regulated in presence of chloride were those related to lipopolysaccharide and peptidoglykane synthesis, and interestingly also those for (hydroxy) ectoine biosynthesis.