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Legionella pneumophila transcriptional response following exposure to CuO nanoparticles
Citation:
Lu, J., I. Struewing, H. Buse, J. Kou, H. Shuman, S. Faucher, AND N. ASHBOLT. Legionella pneumophila transcriptional response following exposure to CuO nanoparticles. APPLIED AND ENVIRONMENTAL MICROBIOLOGY. American Society for Microbiology, Washington, DC, 79(8):2713-2720, (2013).
Impact/Purpose:
This research was to characterize gene expression in L. pneumophila during exposure to CuO-NPs, and to quantify variations in the expression of key genes with an emphasis on potential cell virulence factors.
Description:
Copper ions are an effective antimicrobial agent used to control Legionnaires’ disease and Pontiac fever arising from institutional drinking water systems. Here we present data on an alternative bactericidal agent, CuO nanoparticles (CuO-NPs), and test its efficacy at three concentrations (80, 160 and 240 μg mL-1) on L. pneumophila by measuring colony forming units (cfu) and changes in RNA expression using microarray and RT-qPCR assays. In broth cultures, the CuO-NPs caused growth inhibition, which appeared to be concentration and exposure time dependent. At 160 μg mL-1 CuO-NPs for 3 h exposure time, a high proportion of genes involved in metabolism, transcription, translation, replication-repair and tRNA, and unknown/hypothetical proteins were expressed. For some virulence genes, this response occurred immediately after addition of CuO NPs to the cells and faded within 3 h (icmV, icmW, lemA), while some gene expressions increased to 9-h (ceg29, legLC8, legP, lem19, lem24, lpg1689 and rtxA), 12-h (cegC1, dotA, enhC, htpX, icmE, pvcA and sidF), and for others upto 24-h (legP, lem19 and ceg19), but for most of the genes tested, expression ceased by 24-h. Genes like ceg29 and rtxA appeared to be most responsive to Cu-NPs exposures. The genes unassociated with virulence tended to decrease expression (copA) or show no change (csrA and ropD). Overall, most genes tested showed an immediate reduction in expression as cfu counts rapidly declined to below detection within 24 h. The information derived from this experiment will help us to identify PCR assays during disinfection process and understand disinfection effects on L. pneumophila and may aid in management strategies for the application of CuO-NPs in drinking water treatment.
