|Robert K. Ernst, Ph.D.||Microbial Pathogenesis|
Robert (Bob) K. Ernst, Ph.D., is an Associate Professsor in the Department of Microbial Pathogenesis in the school of dentistry and an Adjunct Associate Professor in the school of medicine. In the fall of 2008, I moved my laboratory from the University of Washington, Seattle, where I was a Research Associate Professor in the Department of Medicine, Division of Allergy and Infectious Diseases and a principal investigator with the Northwest Regional Center of Excellence for Biodefense and Emerging Infectious Diseases Research (NWRCE) to the University of Maryland. I received my B.S. from the State University of New York at Oswego (biology and chemistry), an M.A. from SUNY Buffalo (Microbiology), and a Ph.D. from the University of Virginia (Microbiology) studying retroviral RNA transport, where I was also a fellow in the Myles H. Thaler Center for Retrovirus Research. Subsequently, I was a senior fellow at University of Washington in the laboratory of Samuel I. Miller (Allergy and Infectious Diseases) from 1997 – 2002 before joining the faculty in 2002.
The current research goals of my laboratory are to understand the molecular basis and adaptive significance of modifications to the structure of lipopolysaccharide (LPS), the major surface molecule and pathogenic factor of Gram-negative bacteria and its interaction with the host innate immune system (seefor ongoing projects).
Dr. Bob Ernst, Ph.D.
Associate Professor, Department of Microbial Pathogenesis, Dental School,
Adjunct Assistant Professor, Dept. of Microbiology and Immunology, School of Medicine,
University of Maryland, The Founding Campus,
8th Floor South, 650 W. Baltimore Street, Baltimore, Maryland 21201
Office 9209; Laboratory 9414
Telephone: 410.706.2263, Fax: 410.706.0865, Laboratory: 410.706.6112, Main Office: 410.706.7090
CURRICULUM VITAE (Click to download PDF)
Jones JW, Cohen IE, Tureček F, Goodlett DR, and Ernst RK (2010) Comprehensive Structure Characterization of Lipid A Extracted From Yersinia pestis for Determination of its Phosphorylation Configuration. J Am Soc Mass Spectrom. Accepted for publication 1/8/10.
Pilonieta MC, Erickson KD, Ernst RK, and Detweiler CS. (2009) A Protein Important for Antimicrobial Peptide Resistance, YdeI/OmdA, is in the Periplasm and Interacts with OmpD/NmpC. J Bacteriol. 191:7243-52.
Buchanan PJ, Ernst RK, Elborn JS, and Schock B. (2009) Role of CFTR, Pseudomonas aeruginosa and Toll-like receptors in cystic fibrosis lung inflammation. Biochem Soc Trans. 37(Pt 4):863-7.
Coats SR, Jones JW, Do CT, Braham PH, Bainbridge BW, To TT, Goodlett DR, Ernst RK, and Darveau RP. (2009) Human Toll-like receptor 4 responses to P. gingivalis are regulated by lipid A 1- and 4'-phosphatase activities. Cell Microbiol. 11:1587-99.
Berezow AB, Ernst RK, Coats SR, Braham PH, Karimi-Naser LM, and Darveau RP. (2009) The structurally similar, penta-acylated lipopolysaccharides of Porphyromonas gingivalis and Bacteroides elicit strikingly different innate immune responses. Microb Pathog. 47:68-77.
Kalhorn TF, Kiavand A, Cohen IE, Nelson AK, and Ernst RK. (2008) A sensitive liquid chromatography/mass spectrometry-based assay for quantitation of amino-containing moieties in lipid A. Rapid Communications in Mass Spectrometry. 23:433-442.
West TE, Ernst RK, Jansson-Hutson MJ, and Skerrett SJ. (2008) Activation of Toll-like receptors by Burkholderia pseudomallei. BMC Immunol. 8:46.
Jones JW, Shaffer SA, Ernst RK, Goodlett DR, and Tureček F. (2008) Determination of Pyrophosphorylated Forms of Lipid A in Gram-Negative Bacteria Using a Multi-Varied Mass Spectrometric Approach. Proc Nat Acad Sci. 105:12742-12747.
Bainbridge BW, Karimi-Naser L, Reife R, Blethen F, Ernst RK, and Darveau RP. (2008) Acyl chain specificity of the acyltransferases lpxA and lpxD and substrate availability contribute to lipid A fatty acid heterogeneity in Porphyromonas gingivalis. J. Bact. 190:4549-4558.
Miao EA, Ernst RK, Dors M, Mao DP, and Aderem A. (2008) Pseudomonas aeruginosa activates caspase 1 though Ipaf . Proc Nat Acad Sci. class. 105:2562-7
Kanistanon D, Hajjar AM, Pelletier MR, Gallagher LA, Kalhorn T, Shaffer SA, Goodlett DR, Rohmer L, Brittnacher M, Skerrett SJ, and Ernst RK (2008) A Francisella Mutant in Lipid A Carbohydrate Modification Elicits Protective Immunity. PLoS Pathogens. 4:e24.
Ernst RK, Moskowitz SM, Emerson JC, Kraig GM, Adams KN, Harvey MD, Ramsey BW, Speert DP, Burns JL and Miller SI. (2007) Unique lipid A modifications in Pseudomonas aeruginosa isolated from the airways of patients with cystic fibrosis. J. Infect. Diseases. 196:1088-1092.
Rohmer L, Fong C, Abmayr S, Wasnick M, Freeman TJ, Radey M, Guina T, Svensson K, Hayden HS, Jacobs M, Gallagher LA, Manoil C, Ernst RK, Drees B, Buckley D, Haugen E, Bovee D, Zhou Y, Chang J, Levy R, Lim R, Gillett W, Guenthener D, Kang A, Shaffer SA, Taylor G, Chen J, Gallis B, D'Argenio DA, Forsman M, Olson MV, Goodlett DR, Kaul, RMiller SI, Brittnacher MJ. (2007) Comparison of Francisella tularensis genomes reveals evolutionary events associated with the emergence of human-pathogenic strains. Genome Biol. 8:R102.
Mohapatra NP, Soni S, Bell BL, Warren R, Ernst RK, Muszynski A, Carlson R and Gunn JS. (2007) Identification of an orphan response regulator required for Francisella virulence and transcription of pathogenicity island genes. Infect. Immun. 75:3305-3314.
Murray SR, Ernst RK, Bermudes D, Miller SI and Low KB. (2007) PmrAC confers pmrHFIJKL-dependent EGTA and polymyxin resistance to msbB Salmonella by decorating lipid A with phosphoethanolamine. J. Bact. 189:5161-5169.
ShafferSA, HarveyMD, GoodlettDR, and Ernst RK. (2007) Structural Heterogeneity and Environmentally Regulated Remodeling of Francisella tularensis subspecies novicida Lipid A Characterized by Tandem Mass Spectrometry. J Am Soc Mass Spectrom. 18:1080-1092.
D’Argenio DA, Hoffman LR, Deziel E, Smith EE, Hayden H, Klausen M, Ernst RK, Burns JL, Ramsey BW, Speert DP, Olson MV and Miller SI. (2007). Growth phenotypes of Pseudomonas aeruginosa lasR mutants adapted to the airways of cystic fibrosis patients. Mol Microbiol. 64:512-533.
Waters VJ, Gomez MI, Soong G, Amin S, Ernst RK, and Prince A. (2007) Immunostimulatory properties of the emerging pathogen Stenotrophomonas maltophilia. Infect Immun. 75:1698-1703.
Haagensen JAJ, Klausen M, Ernst RK, Miller SI, Folkesson A, Tolker-Nielsen T and Molin S. (2006) Differentiation and Distribution of Colistin/SDS Tolerant Cells in Pseudomonas aeruginosa Biofilms. J Bact. 189:28-37.
Hajjar AM, Harvey MD, Shaffer SA, Goodlett DR, Sjostedt A, Edebro H, Forsman M, Byström M, Pelletier M, Wilson CB, Miller SI, Skerrett SJ and Ernst RK. (2006) Lack of in vitro and in vivo recognition of Francisella subspecies LPS by Toll-like receptors. Infect Immun. 74:6730-6738.
Rebeil R, Ernst RK, Jarrett CO, Adams KN, Miller SI, and Hinnebusch BJ. (2006) Characterization of Late Acyltransferase Genes of Yersinia pestis and their Role in Temperature-dependent Lipid A Variation. J Bact. 188:1381-1388.
Ernst RK, Adams, KN, Moskowitz, SM, Kraig, GM, Kawasaki, K, Stead CM, Trent MS, and Miller SI. (2006) The Pseudomonas aeruginosa Lipid A Deacylase: Selection for Expression and Loss Within the Cystic Fibrosis Airway. J Bact. 188:191-201.
Bylund J, Burgess L-A, Cescutti P, Ernst RK, and Speert DP. (2005) Exopolysaccharides from Burkholderia cenocepacia inhibit neutrophil chemotaxis and scavenge reactive oxygen species. J Biol Chem. 281:2526-32.
Kawasaki K, Ernst RK, and Miller SI (2005) Inhibition of Salmonella enterica serovar Typhimurium lipopolysaccharide deacylation by aminoarabinose membrane modification. J. Bact. 187:2448-2457.
Tanabe H, Ayabe T, Bainbridge B, Guina T, Ernst RK, Darveau RP, Miller MI, and Ouellette AJ. (2005) Mouse Paneth Cell Secretory Responses to Cell Surface Glycolipids of Virulent and Attenuated Pathogenic Bacteria. Infect Immun. 73:2312-2320.
Beckmann C, Britmacher M, Ernst RK, Hamblett N, Miller SI, and Burns J. (2005) The use of phage display to identify potential Pseudomonas aeruginosa gene products relevant to early cystic fibrosis airway infections. Infect Immun. 2005 73:444-452.
Kawasaki K, Ernst RK, Miller SI. (2004) Deacylation and palmitoylation of lipid A by Salmonellae outer membrane enzymes modulate host signaling through Toll-like receptor 4. J Endotoxin Res 10: 439-444.
Lindgren H, Golovliov I, Baranov V, Ernst RK, Telepnev M, and Sjostedt A. (2004) Factors affecting the escape of Francisella tularensis from the phagolysosome. J Med Microbiol 53: 953-958.
Rebeil R*, Ernst RK*, Gowen BB, Miller SI and Hinnebusch BJ. (2004) Variation in lipid A structure in the pathogenic yersiniae. Mol Micro 52: 1363-1373. * Co-first authors
Skerrett SJ, Liggitt HD, Hajjar AM, Ernst RK, Miller SI, and Wilson CB. (2004) Respiratory Epithelial Cells Regulate Lung Inflammation in Response to Inhaled Endotoxin. Am J Physiol Lung Cell Mol Physiol 287 :L143-152.
Kawasaki K, Ernst RK, and Miller SI. (2004) 3-O-deacylation of lipid A by PagL, a PhoP/PhoQ-regulated deacylase of Salmonella typhimurium, modulates signaling through toll-like receptor 4. J Biol Chem 279: 20044-20048.
Moskowitz SM, Ernst RK and Miller SI. (2004). PmrAB, a Two-Component Regulatory System of Pseudomonas aeruginosa that Modulates Resistance to Cationic Antimicrobial Peptides and Addition of Aminoarabinose to Lipid A. J Bacteriol 186: 575-579.
Ernst RK, Hajjar AM, Tsai JH, Moskowitz SM, Wilson CB, and Miller SI. (2003). Pseudomonas aeruginosa Lipid A Diversity and its Recognition by Toll-like Receptor 4. J Endotoxin Research 9:3 95-400.
Ernst RK, D´Argenio DA, Ichikawa JK, Bangera MG, Selgrade S, Burns JL, Hiatt P, McCoy K, Brittnacher M, Kas A, Spencer DH, Olson MV, Ramsey BW, Lory S and Miller SI. (2003). Genome mosaicism is conserved but not unique in Pseudomonas aeruginosa isolates from the airways of young children with cystic fibrosis. Environmental Microbiology 5: 1341-1349.
Guina T, Wu M, Miller SI, Purvine SO, Yi EC, Eng J, Goodlett DR, Aebersold R, Ernst RK, Lee KA. (2003). Proteomic analysis of Pseudomonas aeruginosa grown under magnesium limitation. J Am Soc Mass Spectrom. 7: 742-751.
Plesner A, Greenbaum CJ, Guar LK, Ernst RK, Miller SI, Lernmark A (2002). Macrophages from high risk HLA-DQB1*0201/0302 type 1 diabetes mellitus patients are hypersensitivity to lipopolysaccharide stimulation. Scand. J. Immunol 56: 522-529.
Brodsky IE, Ernst RK, Miller SI, Falkow S (2002). Mig-14 (pmrO) is involved in Salmonella resistance to antimicrobial peptides. J Bacteriol 184: 3203-3213.
Hajjar AM*, Ernst RK*, Tsai JH, Wilson CB, Miller SI. (2002). Human Toll-like receptor 4 recognizes host-specific LPS modifications. Nature Immunology 3: 354-935. * Co-first authors
Perez-Melgosa M, Ochs HD, Linsley PS, Laman JD, van Meurs M, Flavell RA, Ernst RK, Miller SI, Wilson CB. (2001) Carrier-mediated enhancement of cognate T cell help: the basis for enhanced immunogenicity of meningococcal outer membrane protein polysaccharide conjugate vaccine. Eur J Immunol 31: 2373-2381.
Gunn JS, Ryan SS, Van Velkinburgh JC, Ernst RK, Miller SI. (2000). Genetic and functional analysis of a PmrA-PmrB-regulated locus necessary for lipopolysaccharide modification, antimicrobial peptide resistance, and oral virulence of Salmonella enterica serovar typhimurium. Infect Immun 68: 6139-6146.
Yethon JA, Gunn JS, Ernst RK, Miller SI, Laroche L, Malo D, Whitfield C. (2000) Salmonella enterica serovar typhimurium waaP mutants show increased susceptibility to polymyxin and loss of virulence In vivo. Infect Immun 68: 4485-4491.
Ernst RK, Yi EC, Guo L, Lim KB, Burns JL, Hackett M, Miller SI. (1999). Specific lipopolysaccharide found in cystic fibrosis airway Pseudomonas aeruginosa. Science 286: 1561-1565.
Gunn JS, Ernst RK, McCoy AJ, Miller SI. (2000). Constitutive mutations of the Salmonella enterica serovar typhimurium transcriptional virulence regulator phoP. Infect Immun 68: 3758-3762.
Pasquinelli, AE, Ernst RK, Lund E, Grimm C, Zapp M, Rekosh R, Hammarskjold M-L and Dahlberg JE (1997). The constitutive transport element (CTE) of Mason-Pfizer Monkey Virus (MPMV) accesses a cellular mRNA export pathway and binds specific proteins. EMBO J 16: 7500-7510.
Ernst RK, Bray M, Rekosh D and Hammarskjold M-L (1997). Secondary structure and mutational analysis of the Mason-Pfizer Monkey Virus RNA constitutive transport element. RNA 3: 210-222.
Ernst RK, Bray M, Rekosh D and Hammarskjold M-L (1997). The Mason-Pfizer Monkey Virus genome contains a structured RNA element that serves as an export signal for intron-containing RNA. Mol Cell Biol. 17: 135-144.
Ernst RK, Dombroski DM and Merrick JM (1990). Anaerobiosis, type 1 fimbriae and growth phase are factors that affect invasion of HEp-2 cells by Salmonella typhimurium. Infect Immun 58: 2014-2016.
Abud RL, Lindquist BL, Ernst RK, Merrick JM, Lebanthale and Lee PC (1989). Concanavalin A promotes adherence of Salmonella typhimurium. Proc Soc Exp Biol Med 192: 81-86.
Reviews and Book Chapters
Gunn JS and Ernst RK. The Structure and Function of Francisella LPS. (2007) Ann N Y Acad Sci. 1105:202-218.
Miller SI, Ernst RK, and Bader MW. (2005) LPS, TLR4 and infectious disease diversity. Nature Rev Microbiol. 1:36-46.
Ernst RK, Guina T, and Miller SI (2001) Salmonella typhimurium Outer Membrane Remodeling: Role in Resistance to Host Innate Immunity. Microbes Infect. 2001 3:1327-1334.
Ernst RK and Miller SI (2000). Peptides, Pseudomonas aeruginosa, polysaccharides and lipopolysaccharides - players in the predicament of cystic fibrosis patients: Response. Trends Microbiol. 8:250-251.
Ernst RK, Guina T, and Miller SI (1999). How intracellular bacteria survive: surface modifications that promote resistance to host innate immune responses. J Infect Dis 179: Suppl 2:S326-330.
Ad Hoc Review: Infection and Immunity, FEMS Micro, Journal of Bacteriology, Journal of Infectious Diseases, Infection and Immunity, FEBS Journal, Cellular Microbiology, Molecular Microbiology, Journal of Clinical Investigations, Molecular Microbiology, Journal of Interferon & Cytokine Research
Grant Review: National Institutes of Health, Cystic Fibrosis Foundation, Canadian Institutes of Health Research
National and International Presentations
2010 University of Maryland-College Park, Departmental Seminar Series, College Park, MD
2009 Queen's University, Respiratory Medicine Programme, Belfast, Ireland
2009 Walter Reed Research Center, Washington, DC
2009 Mid-Atlantic Microbial Pathogenesis, Wintergreen, VA
2008 International Endotoxin and Innate Immunity Society, Edinburgh, Scotland
2008 American Chemical Society Western Regional Meeting, Las Vegas, NV
2007 University of Illinois at Chicago, , Chicago, IL
2007 University of Maryland, Departmental Seminar Series, Baltimore, MD
2006 International Endotoxin and Innate Immunity Society, San Antonio, TX
2005 Northwest Gene Expression Conference, Seattle, WA
2005 Tularemia Workshop, Hancock, MA
2005 Columbia University, Infectious Diseases Seminar Series, New York, NY
2004 University of Idaho, Departmental Seminar Series, Moscow, ID
2004 Regional Centers for Excellence-National Biodefense meeting, Bethesda, MD
2004 International Endotoxin and Innate Immunity Society, Kyoto, Japan
2004 Pacific Northwest Mass Spectrometry seminar series, Seattle, WA
2003 Keck Center for Microbial Pathogenesis, Seattle, WA
2003 43rd Conference on Antimicrobial Agents and Chemotherapy, Chicago, IL
Work Experience in Higher Education
Associate Professor: Department of Microbial Pathogenesis, Dental School, University of Maryland – Baltimore, Baltimore, MD, 2008 - present
Adjunct Associate Professor: Department of Microbiology and Immunology, Medical School, University of Maryland – Baltimore, Baltimore, MD, 2008 - present
Research Associate Professor: Department of Medicine, Division of Allergy and Infectious Diseases, Universirty of Washington, Seattle WA, 2007-2008
Research Assistant Professor: Department of Medicine, Division of Allergy and Infectious Diseases, Universirty of Washington, Seattle WA, 2002-2007
Postdoctoral Fellow: Department of Medicine and Microbiology, University of Washington, Seattle, WA.
Advisor: Dr. Samuel I Miller. 1997-2002
Postdoctoral Fellow: Myles H. Thaler Center for Retrovirus Research. Department of Microbiology. University of Virginia, Charlottesville, VA. Advisor: Dr. Marie-Louise Hammarskjöld and Dr. David Rekosh . 1996-1997
PhD - "Characterization of an element in the Mason-Pfizer Monkey Virus which mediates the nucleocytoplasmic export of intron-containing RNA." Myles H. Thaler Center for Retrovirus Research. Department of Microbiology. University of Virginia, Charlottesville, VA. Advisor: Dr. Marie-Louise Hammarskjöld and Dr. David Rekosh. 1996
MA - "Studies on the invasion of epithelial cells by Salmonella typhimurium." Department of Microbiology. State University of New York at Buffalo, Buffalo, New York. 1988.
BS - State University of New York at Oswego, Oswego, New York.
Instructor and Coordinator, MICP 521I – General & Orofacial Infectious Diseases, University of Maryland, Baltimore. Fall, 2009 – present.
Instructor, NSPR 518C – Clinical Research Conferences, University of Maryland, Baltimore. Fall, 2009 – present.
Instructor, MSPR 520 – Host Defenses and Infectious Diseases, University of Maryland, Baltimore. Fall, 2009 – present.
Instructor, DBMS 635 – Bacterial Genetics, University of Maryland, Baltimore. Fall 2009 - present.
“Burkholderia pseudomallei and mallei lipid A structure” National Institutes of Health – Developmental Project, Northwest RCE, U54 AI057141. 12/1/09 – 11/30/10. Goals - To define and elucidate the mechanism of the synthesis of environmentally-regulated lipid A structures from B. pseudomallei and mallei, potential agents of bioterrorism.
“Pseudomonas aeruginosa Lipid A” National Institutes of Health – R01- AI047938-06A1. 8/1/06 - 7/31/11. Goals - defining genes important for the synthesis of cystic fibrosis (CF)-specific lipid A in Pseudomonas aeruginosa.
“Protein, Lipid, Chemical, and Structural Signatures of Differentially-Cultivated Francisella tularensis and Acinetobacter baumannii” Program Project. US Army Medical Research & Material Command. 5/1/10 – 4/30/15. Goals - Define the lipodomic and LPS profile for Francisella tularensis and Acinetobacter baumannii grown under different culture conditions to define specific chemical signatures.