Department of Molecular Biology
University of Wyoming
Laramie, WY 82071
B.S., Biochemistry, The Pennsylvania State University, 1977
Ph.D., Biochemistry, Boston University, 1982
Current research in the Miller lab is focused on understanding how the foodborne pathogen, Listeria monocytogenes, is able to persist in the environment, leading to contamination of produce and other foods, and food processing equipment. One phenotype we have discovered in collaboration with Mark Gomelsky at the Univ. of Wyoming that appears to contribute to environmental persistence of listerial cells is a novel exopolysaccharide (EPS) consisting of a ManNAc2-Gal repeat unit. When this extracellular polymer is overexpressed, cells become several orders of magnitude more resistant to disinfectants such as bleach, and several fold more resistant to desiccation. ManNAc2-Gal EPS is synthesized by enzymes encoded in the polysaccharide synthesis pssABCDE operon. PssC and PssD are the core enzymes needed for synthesis of this EPS, while PssA and PssB play ancillary functions in its expression. The activity of the PssCD polymerase is controlled post-translationally by the signaling molecule, cyclic-dimeric GMP (c-di-GMP). We have shown that the PssE protein binds c-di-GMP, and in the bound form, stimulates EPS synthesis by PssCD. Lastly, we have determined that a listerial glycosylhydrolase, PssZ, degrades ManNAc2-Gal EPS, dispersing clumped listerial cells growing as suspended biofilms. PssZ therefore may be an important agent for clearing biofilms from produce or food processing equipment. In the future, we will further explore the role of c-di-GMP in environmental persistence and in the transition of L. monocytogenes to an intracellular pathogen. Two recent publications describing the above research findings are listed in the publication list below. Earlier publications concerning the control of listerial growth by the bacteriocin pediocin PA-1, and regulation of the expression of the pediocin PA-1 receptor, the EIItMan permease, are also listed.
Koseoglu, V. K., Heiss, C., Azadi, P., Topchiy, E., Guvener, Z. T., Lehmann, T. E., Miller, K. W., and Gomelsky, M. 2015. Mol. Microbiol. 96, 728-743. "Listeria monocytogenes Exopolysaccharide: Origin, Structure, Biosynthetic Machinery and c-di-GMP-dependent Regulation."
Chen, L. H., Koseoglu, V. K., Guvener, Z. T., Myers-Morales, T., Reed, J. M., D'Orazio, S. E. F., Miller, K. W., and Gomelsky, M. 2014. PLoS Pathog. DOI: 10.1371/journal.ppat.1004301. "Cyclic di-GMP-dependent Signaling Pathways in the Pathogenic Firmicute Listeria monocytogenes."
Vu-Khac, H., and Miller, K. W. 2009. Appl. Environ. Microbiol. 75, 6671-6678. "Regulation of Mannose Phosphotransferase System Permease and Virulence Gene Expression in Listeria monocytogenes by the EIItMan Transporter.
Xue, J., C. M. Murrieta, D. C. Rule, and K. W. Miller. 2008. Exogenous or L-rhamnose-derived 1,2-propanediol is metabolized via a pduD-dependent pathway in Listeria innocua. Appl. Environ. Microbiol. 74:7073-7079.
Xue, J., and Miller, K. W. 2007. Appl. Environ. Microbiol. 73, issue 17 in press. "Regulation of the mpt Operon in Listeria innocua by the ManR Protein."
Miller, K. W., Ray, P., Steinmetz, T., Hanekamp, T., and Ray, B. 2005. Lett. Appl. Microbiol. 40, 56-62. "Gene Organization and Sequences of Pediocin AcH/PA-1 Production Operons in Pediococcus and Lactobacillus Plasmids."
Xue, J., Hunter, I., Steinmetz, T., Peters, A., Ray, B., and Miller, K. W. 2005. Appl. Environ. Microbiol. 71, 1283-1290. "Novel Activator of Mannose-Specific Phosphotransferase System Permease Expression in Listeria innocua, Identified by Screening for Pediocin AcH Resistance."
Ray, B., and Miller, K. W. 2003. In "Natural Antimicrobials for the Minimal Processing of Foods," S. Roller, Ed. Woodhead Publishing Limited, Cambridge , UK . "Bacteriocins Other Than Nisin: the Pediocin-like Cystibiotics of Lactic Acid Bacteria." pp. 64-81
Lewis, G. S., Jewell, J. E., Phang, T., and Miller, K. W. 2003. Biochem. Biophys. Res. Comm. 305, 1067-1072. "Mutational and Sequence Analysis of Transmembrane Segment 6 Orientation in TetA Proteins."
Lewis, G. S., Jewell, J. E., Phang, T., and Miller, K. W. 2002. Arch. Biochem. Biophys. 404, 317-325. "Mutational Analysis of Tetracycline Resistance Protein Transmembrane Segment Insertion."
Watson, R. M., Woody, R. W., Lewis, R. V., Bohle, D. S., Andreotti, A. H., Ray, B., and Miller, K. W. 2001. Biochemistry 40, 14037-14046. "Conformational Changes in Pediocin AcH upon Vesicle Binding and Approximation of the Membrane-bound Structure in Detergent Micelles."
Ray, B., and Miller, K. W. 2000. In "Natural Food Antimicrobial Systems," A. S. Naidu, Ed. CRC Press, Boca Raton, FL. "Pediocins of Pediococcus Species." pp. 525-566.
Ray, B., Schamber, R., and Miller, K. W. 1999. Appl. Environ. Microbiol. 65, 2281-2286. "The Pediocin AcH Precursor Is Biologically Active."
Jewell, J. E., Orwick, J., Liu, J., and Miller, K. W. 1999. J. Bacteriol. 181, 1689-1693. "Functional Importance and Local Environments of the Cysteines in the Tetracycline Resistance Protein Encoded by Plasmid pBR322."
Miller, K. W., Schamber, R., Osmanagaoglu, O., and Ray, B. 1998. Appl. Environ. Microbiol. 64, 1997-2005. "Isolation and Characterization of Pediocin AcH Chimeric Protein Mutants with Altered Bactericidal Activity."
Miller, K. W., Schamber, R., Chen, Y., and Ray, B. 1998. Appl. Environ. Microbiol. 64, 14-20. “Production of Active Chimeric Pediocin AcH in Escherichia coli in the Absence of Processing and Secretion Genes from the Pediococcus pap Operon.”