Robert McLean, Ph.D.
Pathogenic Microbiology (BIO 4445/5445)
Microbial Physiology and Genetics (BIO 4447/7447)
Most bacteria in their natural environments live on surfaces as slime-encased, biofilm communities. In contrast to their planktonic counterparts, sessile bacterial populations are significantly more resistant to environmental stresses such as harmful chemicals, antibiotics and predation. While biofilms are the dominant form of growth of bacteria in nature, little is known about the biological factors that allow growth as biofilms. Studies in my lab, done in collaboration with Debby Siegele, Clay Fuqua, Walt Fast, Dhiraj Vattem, and Sandy Pierson, address three major aspects of bacterial physiology which are important in biofilm growth and development: ability of individual bacteria to grow slowly, survive starvation stresses, and express a variety of biofilm-activated genes. In addition, individual bacteria within a biofilm community perform many metabolic activities as a group through a phenomenon known as quorum-sensing. Recently in collaboration with Marvin Whiteley and Tom Wood, we have expanded these studies by employing gene arrays and transcriptional profiling to investigate overall patterns of gene expression in mixed culture bacterial biofilms. Aside from their importance on earth, biofilms may also impact the success of future long-term space flights due to possible fouling of water recycling filters. In an experiment on the John Glenn space shuttle, Pseudomonas aeruginosa formed biofilms under weightless conditions. Bacteria have also been associated with the formation of many types of sedimentary rocks and minerals. Our current thinking is that ultra-small fossilized bacteria (“nanobacteria”) may represent remnants of bacterial polymers (slime). We plan to further investigate whether they are involved in mineral formation.
LB Coulter, RJC McLean, RE Rohde, and GM Aron. 2014. Effect of bacteriophage infection in combination with tobramycin on the emergence of resistance in Escherichia coli and Pseudomonas aeruginosa biofilms. Viruses 6: 3778-3786.
Shay M, M Al-Tameemi, S Wright, RJC McLean, DA Vattem, and V Maitin. 2014. Method development for investigating probiotic effects on fat storage in a Caenorhabditis elegans model. FASEB J 1 (Suppl): 829-833.
Vega LM, PJ Alvarez, and RJC McLean. 2014 Bacterial signaling ecology and potential applications during biofilm construction. Microb. Ecol. 68: 24-34.
Vega LM, J Mathieu, Y Yang, BH Pyle, RJC McLean, and PJ Alvarez. 2014 Nickel and cadmium, ions inhibit quorum sensing and biofilm formation without affecting viability in Burkholderia multivorans. Intern. Biodeterior. Biodegrad. 91: 82-87.
Taylor AA, GM Aron, GW Beall, N Dharmasiri, Y Zhang, and RJC McLean. 2014. Carbon and clay nanoparticles induce minimal stress responses in Gram negative bacteria and eukaryotic fish cells. Environ. Toxicol. 29: 961-968.
McLean RJC and SL Pringle. 2013. Identifying bacterial menu choices from the host buffet during infections. Journal of Bacteriology 195: 4989-4990.
McLean RJC and KS Kakirde. 2013. Enhancing metagenomics investigations of microbial interactions with biofilm technology. Int. J. Mol. Sci. 14: 22246-22257.
Chu, W, TR Zere, MM Weber, TK Wood, M Whiteley, B Hidalgo-Romano, E. Valenzuela, and RJC McLean. 2012. Indole production promotes Escherichia coli mixed culture growth with Pseudomonas aeruginosa by inhibiting quorum signaling. Appl. Environ. Microbiol. 78: 411-419.
Kay MK, TC Erwin, RJC McLean, and GM Aron. 2011. Bacteriophage ecology in Escherichia coli and Pseudomonas aeruginosa mixed biofilm communities. Appl. Environ. Microbiol. 77: 821-829.
Please see faculty member’s CV or website for a complete list of publications and additional information.