Project description:Regulatory elements that dictate how Haemophilus influenzae adapts to the airways of COPD patients are poorly understood. In this work, global fitness profiling of H. influenzae mutants by transposon mutagenesis/sequencing (Tn-seq) within the mouse lung identified Dam methyltransferase as an in vivo requirement, even though dam mutants grow normally during in vitro culture. In turn, methylation sequencing found that genome-wide Dam methylation patterns were undermethylated at GATC motifs with putative regulatory elements. This was confirmed for the htpG heat-shock chaperone gene, making it the first case of phenotypic variation controlled by variable Dam methylation for H. influenzae. Moreover, RNA sequencing revealed a novel multifactorial regulatory network, in which Dam methyltransferase activity is coordinated with the FNR and Fur transcriptional regulators to control the expression anaerobic defences against host-produced reactive species. Our results indicate key bacterial pathways for survival in diseased environments with high nitrosative stress, where damage to the airways reduces the amount of oxygen in the lungs as is encountered in COPD.
Project description:Characterization of a novel haem-binding protein produced by Haemophilus haemolyticus, isolated and purified from non-typeable Haemophilus influenzae (NTHi)-inhibitory substance.
Project description:Accurate differentiation between closely related Haemophilus species is essential for clinical diagnosis. This study presents a high-resolution proteotyping workflow integrating whole-cell MALDI-TOF MS, nanoLC-MS/MS, and comparative genomics to distinguish H. influenzae and H. aegyptius. We identified 31 robust protein biomarkers validated by LC-MS/MS peptide mapping and comparative genomics, providing enhanced diagnostic resolution for closely related pathogens.
Project description:Characterization of a novel haem-binding protein that is secreted by two Haemophilus haemolyticus isolates, BW1 and RHH122, and that inhibits the growth of the pathogen non-typeable Haemophilus influenzae (NTHi) in vitro.