Journal of Microbial & Biochemical Technology

Phenotypes and mechanical properties of Bacillus subtilis biofilms

Joint Event on 4^th World Congress and Expo on Applied Microbiology & 2^nd International Conference on Food Microbiology

November 29-December 01, 2017 Madrid, Spain

Xiaoling Wang

University of Science and Technology Beijing, China

Scientific Tracks Abstracts: J Microb Biochem Technol

Abstract:

We develop an optical imaging technique for spatially and temporally tracking biofilm growth and the distribution of the main phenotypes of a Bacillus subtilis strain with a triple-fluorescent reporter for motility, matrix production, and sporulation. We develop a calibration procedure for determining the biofilm thickness from the transmission images, which is based on BeerLambertâ??s law and involves cross-sectioning of biofilms. To obtain the phenotype distribution, we assume a linear relationship between the number of cells and their fluorescence and determine the best combination of calibration coefficients that matches the total number of cells for all three phenotypes and with the total number of cells from the transmission images. Based on this analysis, we resolve the composition of the biofilm in terms of motile, matrix-producing, sporulating cells and low-fluorescent materials which includes matrix and cells that are dead or have low fluorescent gene expression. We take advantage of the circular growth to make kymograph plots of all three phenotypes and the dominant phenotype in terms of radial distance and time. To visualize the nonlocal character of biofilm growth, we also make kymographs using the local colonization time. Our technique is suitable for realtime, noninvasive, quantitative studies of the growth and phenotype distribution of biofilms which are either exposed to different conditions such as biocides, nutrient depletion, dehydration, or waste accumulation.

Biography :

Xiaoling Wang is a Full Professor of School of Mechanical Engineering at USTB, and a visiting scholar of School of Engineering and Applied Science at Harvard University. She received her BS and MS degrees in Solid Mechanics from Beijing Institute of Technology in 2000 and 2003, and a PhD degree in Mechanical Engineering from The Hong Kong University of Science and Technology in 2006. She was an Postdoctoral fellow at The Hong Kong University from 2006 to 2007, and moved to USTB in 2008. she was a Visiting Scholar in the Northwestern University of USA. Her research interests focus on Biomechanics, Phase Transitions in Bio System, Bacterial biofilms.