Methods Bacterial strains and growth conditions The strains and selleck plasmids used in this study are described in Additional

file 1: Table S2. C. crescentus strains were cultured at 30°C in M2 minimal salts medium plus glucose [39]. When appropriate, the growth medium was supplemented with chloramphenicol (1 μg ml-1), kanamycin (10 μg ml-1) or tetracycline (2 μg ml-1). Plasmids were propagated in Escherichia coli strain DH5α (Invitrogen) and mobilized into C. crescentus by bacterial conjugation using E. coli strain S17-1 [40]. E. coli strains were grown at 37°C in LB broth [41]. Deletion of genes CC2906 Androgen Receptor inhibitor and CC3255 in C. crescentus Single mutant strains for CC2906 (SG20) and CC3255 (SG19) were obtained by an in-frame deletion in the coding region of these genes. For that, two fragments flanking the regions to be deleted were amplified by PCR (a complete list of primers used in this study is in Additional file 1: Table S3) and subcloned into pNPTS138 [42]. Constructs into pNPTS138 were transferred to C. crescentus strain NA1000

[43] by conjugation with E. coli S17-1 and the deletion of the wild-type copy of the gene in the NA1000 background was achieved by two homologous recombination events. Mutant strains were isolated by screening colonies by PCR and DNA sequencing. For the construction of a double mutant strain

(SG21), the single mutant strain SG20 was used for the two homologous recombination events of the CC3255 deletion. Construction of point mutations in CC3252 and overexpression of CC3252 in C. Arachidonate 15-lipoxygenase crescentus Codons for the conserved cysteine residues of the protein encoded by CC3252 (C131 and C181) were replaced for a codon corresponding to Blasticidin S serine by overlapping PCR with a pair of complementary primers (Additional file 1: Table S3) designed for each substitution. Each part of CC3252 was amplified separately by PCR using one of each complementary primer set and a primer hybridizing upstream or downstream from CC3252. The partially complementary PCR products were used together as templates in a second amplification reaction with the primers hybridizing upstream and downstream from CC3252. The amplicons obtained were cloned into pGEM-T (Promega) and sequenced. The inserts were excised from vectors and subcloned into pNPTS138. Constructs into pNPTS138 were transferred to C. crescentus strain NA1000 [43] by conjugation with E. coli S17-1 and replacement of the wild-type copy of the gene for the corresponding mutated copy in the NA1000 background was achieved by two homologous recombination events.