AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Proteomic Analysis of Sphingomonas aerolata Incubated in the Airborne State
Valdis Krumins, Maksim Abadjev, Sjef Boeren, Tomas Kruse, Peter Schaap, Hauke Smidt, Gediminas Mainelis, Lee Kerkhof, DONNA FENNELL, Rutgers, The State University of New Jersey
Abstract Number: 188 Working Group: Bioaerosols
Abstract The objective of this study was to analyze the proteomic response of an atmospheric microorganism to aerosolization and the presence of a volatile substrate while airborne.
Sphingomonas aerolata strain NW12 (AJ429240.1), a psychrotolerant bacterium isolated from ambient air and obtained from Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, was used as a model environmentally significant atmospheric bacterial species. The genome of S. aerolata strain NW12 was sequenced using the Illumina HiSeq2000 platform. The genome was annotated and 3344 predicted protein sequences were identified.
S. aerolata was grown in minimal media containing acetic acid as the sole substrate, and then aerosolized into rotating gas-phase bioreactors, which can maintain bacteria in the airborne state for several days. The bacteria were fed either gaseous ethanol or no substrate and incubated for two days. Cells were collected onto membrane filters (Supor, Pall, Port Washington, NY) and proteins were extracted directly from the membranes. Proteins were cleaved into peptides by in-gel trypsin digestion. Proteins were identified using liquid chromatography-mass spectrometry (LC-MS-MS) by matching accurate peptide masses and the corresponding mass fragmentation spectra to the protein database prepared from the sequenced genome.
The aerosolization system and gas-phase rotating reactors were able to produce and maintain approximately 20 to 80 x 106 total cells in suspension over several days, enough for adequate protein capture. Approximately 400 putative proteins were identified from the aerosolized cells, enough to allow comparison of the different treatments. Comparison of four replicate reactor runs in the fed and unfed state to liquid-grown cells indicated differential expression of several proteins in the aerosolized versus liquid-growth cells. Expression of proteins while aerosolized indicates the S. aerolota are active while suspended in air. Rather than being a passive conduit for bacteria, air may be an environment where bacteria carry out active biological functions.