All these short chain aldose sugars mentioned can undergo auto-oxidation to more toxic dicarbonyl species [12]. In this paper we report the effect of reactive carbonyl species on growth of H. influenzae. This provides a new insight into the physiological role of AdhC in non-methylotrophic bacteria. Methods Bacterial strains and growth conditions H. influenzae

strains were cultured on Brain heart infusion (BHI) medium or chemically defined media (CDM). BHI was prepared with 3.7% (wt/vol) BHI Powder (Oxoid). For solid medium, 1.5% (wt/vol) agar powder was added. Medium was sterilized by autoclaving at 121°C for 20 min. Levinthal blood (10% [wt/vol]) was added for solid medium. BHI broth required NAD (2 μg/ml) and 10 μg/ml hemin solution (0.1% [wt/vol] hemin, 0.1% [wt/vol] L-histidine, 4% [vol/vol] triethanolamine). Solutions for C646 mw URMC-099 clinical trial media were sterilized individually, either by NSC 683864 in vivo filter sterilizing or by autoclaving. The solutions were mixed under sterile conditions. CDM was prepared mostly as described by Coleman et al.[13]. The exception to this protocol is the use of RPMI 1640 without glucose (Invitrogen) and the addition of 0.4% of the appropriate

sugar or carbon source. In standard procedures the final pH of CDM was adjusted to 7.56 by NaHCO3. CDM was sterilized by filter sterilization through a 0.22-μm filter. Reverse transcriptase PCR RNA was extracted from H. influenzae Rd KW20 at the time Terminal deoxynucleotidyl transferase points 3 h, 5.5 h and 8 h during growth cycle by using a QIAGEN RNeasy minikit (QIAGEN). RNA was quantified using an A260 reading and then checked for DNA contamination by PCR; no product was detected. RNA was further treated

to remove any residual DNA by using Promega DNase (Promega). The reverse transcriptase (RT) reaction was performed using a QIAGEN Omniscript reverse transcriptase kit. The products of this reaction were used in a multiplex PCR with primers for the 16 S rRNA gene: 16SFOR: 5’-AGTCCACGCCCTAAACGATGT-3’ and 16SREV: 5’-TACTCCCCAGGCGGTCAAT-3’; and primers from estD to adhC: Est1: 5’-CCCAAGGCTGCTCGGTC-3’ and Adh1, 5’-TTCAACGCGTCCGTTCCAA-3’. PCR was carried out with New England Biolabs Taq polymerase using an initial 96°C for 10 min followed by 30 cycles of 96°C for 45 s, 54°C for 45 s, and 72°C for 30 s and a final elongation step of 72°C for 10 min. Growth assays Cells were cultured in rich media (BHI, Oxoid UK) or chemically defined media (CDM). Unless otherwise stated, analysis of the growth of H. influenzae strains was carried out using CDM. For rich media cells were grown on BHI medium supplemented with NAD (2 μg/ml) and 10 μg/ml hemin solution. Overnight growth cultures were inoculated into 5 ml of media and grown until log phase prior to the assay.