Identifying indoor environmental patterns from bioaerosol material using HPLC

Development of an Analytical Method for the Metaproteomic Investigation of Bioaerosol from Work Environments

The metaproteomic analysis of air particulate matter provides valuable information about the properties of bioaerosols in the atmosphere and their influence on climate and public health. In this work, a new method for the extraction and analysis of proteins in airborne particulate matter from quartz microfiber filters is developed. Different protein extraction procedures are tested to select the best extraction protocol based on protein recovery. The optimized method is tested for the extraction of proteins from spores of ubiquitous bacteria species and used for the metaproteomic characterization of filters from three work environments. In particular, ambient aerosol samples are collected in a composting plant, in a wastewater treatment plant, and in an agricultural holding. A total of 179, 15, 205, and 444 proteins are identified in composting plant, wastewater treatment plant, and agricultural holding, (cow stable and blending plant), respectively. In agreement with the major categories of primary biological aerosol particles, all identified proteins originated primarily from fungi, bacteria, and plants. The paper is the first metaproteomic study applied to bioaerosol samples collected in occupationally relevant environmental sites and, even though not aimed at monitoring the risk exposure of workers, it provides information on the possible exposure in the working environmental sites.

Fluorescence detection of protein content in house dust: the possible role of keratin

We propose a fluorescence method for protein content assessment in fine house dust, which can be used as an indicator of the hygienic state of occupied rooms. The results of the measurements performed with 30 house dust samples, including ultrafiltration experiments, strongly suggest that the fluorescence emission of house dust extracts excited at 350 nm is mainly due to protein fragments, which are presumably keratin hydrolysates. This suggestion is supported by several facts: (i) Spectral band shapes for all the samples under investigation are close and correspond to that of keratin; (ii) fluorescence intensity correlates with the total protein content as provided by Lowry assay; (iii) treatment of the samples with proteinase K, which induces keratin hydrolysis, results in fluorescence enhancement without changing fluorescence band shape; and (iv) Raman spectra of keratin and fine house dust samples exhibit a very similar structure. Based on the obtained results and literature data, we propose a hypothesis that keratin is a major substrate for fluorescence species in fine house dust, which are responsible for emission at 350-nm excitation.