Microbiology

Timothy L. Yahr, PhD

Portrait

Professor of Microbiology

Contact Information

Office: 540B Eckstein Medical Research Building
431 Newton Rd
Iowa City, IA 52242
Office Phone: 319-335-9688

Lab: 540 Eckstein Medical Research Building
431 Newton Rd
Iowa City, IA 52242
Phone: 319-335-8666

Email: tim-yahr@uiowa.edu
Web: Yahr Lab Website
Web: Carver College of Medicine Interview
Web: Google Scholar Page

Education

BS, Biology, University of Wisconsin, Stevens Point
MS, Microbiology, Medical College of Wisconsin
PhD, Microbiology, Medical College of Wisconsin

Post Doctoral, Biochemistry, Dartmouth Medical School

Education/Training Program Affiliations

Biosciences Graduate Program
Department of Microbiology Graduate Program
Interdisciplinary Graduate Program in Translational Biomedicine
Medical Scientist Training Program

Research Summary

My laboratory studies regulation of the Pseudomonas aeruginosa type III secretion system (T3SS). T3SS's are unique to Gram-negative bacteria and function to deliver toxins into eukaryotic host cells. The secretion machinery consists of ~30 proteins which span both the inner and outer membranes of the bacterial cell. Following contact of the bacterium with a eukaryotic cell, the type III machinery functions like a molecular syringe to inject toxins into the host cell. Expression of the P. aeruginosa T3SS is highly regulated and induced by at least two environmental cues; contact of the bacteria with eukaryotic cells and growth in the presence of low Ca2+ concentrations. In the absence of these cues, low amounts of the type III secretion channels are assembled within the cell membranes. The channels, however, are inactive and expression of the T3SS is repressed. Expression of the T3SS genes is coupled to type III secretory activity by a cascade of interacting regulatory proteins (ExsA, ExsD, ExsC, and ExsE). ExsA is an activator of type III gene transcription, ExsD binds ExsA to inhibit transcription, ExsC inhibits ExsD activity, and ExsE inhibits ExsC activity. The entire process is coupled to secretion by virtue of the fact that ExsE is a secreted substrate of the T3SS. Changes in the intracellular concentration of ExsE are thought to govern formation of the ExsC-ExsE, ExsC-ExsD, and ExsD-ExsA complexes. Whereas formation of the ExsC-ExsE complex allows ExsD to bind ExsA and transcription of the T3SS is repressed, formation of the ExsC-ExsD complex sequesters ExsD from ExsA and transcription of the T3SS is induced. The major efforts in my lab involve testing the above model and determining how this regulatory cascade interfaces with a number of additional regulatory mechanisms also controlling T3SS gene expression.

Center, Program and Institute Affiliations

Center for Biocatalysis and Bioprocessing
Center for Gene Therapy of Cystic Fibrosis and other Genetic Diseases

All Publications

Marsden A, Schubot F, Yahr T.  Self-association of ExsA is required for occupation of adjacent binding sites on Pseudomonas aeruginosa type III secretion system promoters.  J Bacteriol.  2014 October. 196(20):3546-55.
[Link]

Marsden A, Yahr T.  Amino-Terminal Residues of ExsA Are Required for Self-Association and Interaction with the ExsD Anti-Activator.  General Meeting of the American Society for Microbiology, Boston, MA.  2014. 

Intile P, Diaz M, Urbanowski M, Wolfgang M, Yahr T.  The AlgZR Two-Component System Recalibrates the RsmAYZ Posttranscriptional Regulatory System To Inhibit Expression of the Pseudomonas aeruginosa Type III Secretion System.  J Bacteriol.  2014 January. 196(2):357-66.
[Link]

King J, Schesser Bartra S, Plano G, Yahr T.  ExsA and LcrF recognize similar consensus binding sites, but differences in their oligomeric state influence interactions with promoter DNA.  J Bacteriol.  2013 December. 195(24):5639-50.
[Link]

Heimer S, Evans D, Stern M, Barbieri J, Yahr T, Fleiszig S.  Pseudomonas aeruginosa Utilizes the Type III Secreted Toxin ExoS to Avoid Acidified Compartments within Epithelial Cells.  PLoS One.  2013 September 18. 8(9):e73111.
[Link]

Marden J, Diaz M, Walton W, Gode C, Betts L, Urbanowski M, Redinbo M, Yahr T, Wolfgang M.  An unusual CsrA family member operates in series with RsmA to amplify posttranscriptional responses in Pseudomonas aeruginosa.  Proc Natl Acad Sci U S A.  2013 September 10. 110(37):15055-60.
[Link]

Olson M, King J, Yahr T, Horswill A.  Sialic Acid Catabolism in Staphylococcus aureus.  J Bacteriol.  2013 April. 195(8):1779-88.
[Link]

Berhards R, Marsden A, Esher S, Yahr T, Schubot F.  Self-trimerization of ExsD limits inhibition of the Pseudomonas aeruginosa transcriptional activator ExsA in vitro.  FEBS J.  2013 February. 280(4):1084-94.
[Link]

King J, Bartra S, Plano G, Yahr T.  Reexamining the DNA binding properties of LcrF from Yersinia pestis.  General Meeting of the American Society for Microbiology, Denver, CO.  2013. 

Marsden A, Yahr T.  Residues in the amino-terminal domain of ExsA are required for self-association and interaction with the ExsD anti-activator.  Molecular Genetics of Bacteria and Phages Meeting, Madison, WI.  2013. 

Intile P, Diaz M, Urbanowski M, Wolfgang M, Yahr T.  The AlgZR two-component system recalibrates the RsmAYZ post-transcriptional regulatory system to inhibit expression of the Pseudomonas aeruginosa type III secretion system.  Molecular Genetics of Bacteria and Phages Meeting, Madison, WI.  2013. 

King J, Brutinel E, Marsden A, Schubot F, Yahr T.  Orientation of Pseudomonas aeruginosa ExsA monomers bound to promoter DNA and base-specific contacts with the P(exoT) promoter.  J Bacteriol.  2012 May. 194(10):2573-85.
[Link]

Brutinel E, King J, Marsden A, Yahr T.  The distal ExsA-binding site in Pseudomonas aeruginosa type III secretion system promoters is the primary determinant for promoter-specific properties.  J Bacteriol.  2012 May. 194(10):2564-72.
[Link]

Zheng Z, Ma D, Yahr T, Chen L.  The transiently ordered regions in intrinsically disordered ExsE are correlated with structural elements involved in chaperone binding.  Biochem Biophys Res Commun.  2012 January 6. 417(1):129-34.
[Link]

Marsden A, Schubot F, Yahr T.  Identification of residues in the Pseudomonas aeruginosa transcriptional activator ExsA involved in self-association and interaction with the inhibitor ExsD.  Midwest Microbial Pathogenesis Meeting, Medical College of Wisconsin, Milwaukee, WI.  2012. 

Diaz M, Urbanowski M, Wolfgang M, Yahr T.  RsmA exerts a positive regulatory effect on ExsA expression at the post-transcriptional level.  Midwest Microbial Pathogenesis Meeting, Medical College of Wisconsin, Milwaukee, WI.  2012. 

Intile P, Urbanowski M, Wolfgang M, Yahr T.  The AlgZR two-component system recalibrates the RsmAYZ post-transcriptional regulatory system to inhibit ExsA expression in Pseudomonas aeruginosa ΔmucA isolates.  Midwest Microbial Pathogenesis Meeting, Medical College of Wisconsin, Milwaukee, WI.  2012. 

King J, Bartra S, Plano G, Yahr T.  The transcriptional activators of T3SS gene expression in Pseudomonas aeruginosa, Yersinia pestis, Aeromonas hydrophila, Photorhabdus luminescens, and Vibrio parahaemolyticus recognize a common sequence.  Midwest Microbial Pathogenesis Meeting, Medical College of Wisconsin, Milwaukee, WI.  2012. 

Pezzulo A, Gutiérrez J, Duschner K, McConnell K, Taft P, Ernst S, Yahr T, Rahmouni K, Klesney-Tait J, Stoltz D, Zabner J.  Glucose depletion in the airway surface liquid is essential for sterility of the airways.  PLoS One.  2011 January 20. 6(1):e16166.
[Link]

Diaz M, King J, Yahr T.  Intrinsic and Extrinsic Regulation of Type III Secretion Gene Expression in Pseudomonas aeruginosa.  Front Microbiol.  2011. 2:89.
[Link]

Diaz M, Urbanowski M, Wolfgang M, Yahr T.  RsmA exerts a positive regulatory effect on ExsA expression at a post-transcriptional level.  General Meeting of the American Society for Microbiology, New Orleans, LA.  2011. 

Brutinel E, King J, Yahr T.  The affinity of ExsA for promoter DNA, promoter strength, and the degree of promoter bending are determined by the distal ExsA binding site of T3SS promoters in Pseudomonas aeruginosa.  General Meeting of the American Society for Microbiology, New Orleans, LA.  2011. 

Ahlgren H, Bauerle E, Yahr T, Singh P, Nguyen D.  The stringent response controls virulence in Pseudomonas aeruginosa.  The 25th Annual North American Cystic Fibrosis Conference, Anaheim, CA.  2011. 

Jones A, Fulcher N, Balzer G, Urbanowski M, Pritchett C, Schurr M, Yahr T, Wolfgang M.  Activation of the Pseudomonas aeruginosa AlgU regulon through mucA mutation inhibits cyclic AMP/Vfr signaling.  J Bacteriol.  2010 November. 192(21):5709-17.
[Link]

Vakulskas C, Brutinel E, Yahr T.  ExsA recruits RNA polymerase to an extended -10 promoter by contacting region 4.2 of sigma-70.  J Bacteriol.  2010 July. 192(14):3597-607.
[Link]

Fuchs E, Brutinel E, Jones A, Fulcher N, Urbanowski M, Yahr T, Wolfgang M.  The Pseudomonas aeruginosa Vfr regulator controls global virulence factor expression through cyclic AMP-dependent and -independent mechanisms.  J Bacteriol.  2010 July. 192(14):3553-64.
[Link]

Fuchs E, Brutinel E, Klem E, Fehr A, Yahr T, Wolfgang M.  In vitro and in vivo characterization of the Pseudomonas aeruginosa cyclic AMP (cAMP) phosphodiesterase CpdA, required for cAMP homeostasis and virulence factor regulation.  J Bacteriol.  2010 June. 192(11):2779-90.
[Link]

Brutinel E, Vakulskas C, Yahr T.  ExsD inhibits expression of the Pseudomonas aeruginosa type III secretion system by disrupting ExsA self-association and DNA binding activity.  J Bacteriol.  2010 March. 192(6):1479-86.
[Link]

Anderson G, Yahr T, Lovewell R, O'Toole G.  The Pseudomonas aeruginosa magnesium transporter MgtE inhibits transcription of the type III secretion system.  Infect Immun.  2010 March. 78(3):1239-49.
[Link]

Brutinel E, King J, Yahr T.  The affinity of ExsA for promoter DNA, promoter strength, and the degree of promoter bending are determined by the distal ExsA binding site of T3SS promoters in Pseudomonas aeruginosa.  Midwest Microbial Pathogenesis Meeting, Washington University, St Louis, MO.  2010. 

Urbanowski M, Balzer G, Wolfgang M, Yahr T.  The RsmA and MucA/AlgU Regulatory Systems Independently Control ExsA Expression at the Post-transcriptional Level.  General Meeting of the American Society for Microbiology, San Diego, CA.  2010. 

Urbanowski M, Balzer G, Wolfgang M, Yahr T.  The RsmA and MucA/AlgU Regulatory Systems Independently Control ExsA Expression at the Post-transcriptional Level.  Midwest Microbial Pathogenesis Meeting, Washington University, St Louis, MO.  2010. 

Vakulskas C, Brady K, Yahr T.  Mechanism of transcriptional activation by Pseudomonas aeruginosa ExsA.  J Bacteriol.  2009 November. 191(21):6654-64.
[Link]

Brutinel E, Vakulskas C, Yahr T.  Functional domains of ExsA, the transcriptional activator of the Pseudomonas aeruginosa type III secretion system.  J Bacteriol.  2009 June. 191(12):3811-21.
[Link]

Anderson G, Yahr T, O'Toole G.  Inhibition of Pseudomonas aeruginosa Toxicity Toward Airway Epithelial Cells.  North American Cystic Fibrosis Conference, Minneapolis, MN.  2009. 

Ince D, Wang D, Hopp C, Yahr T.  Secretion of flagellar proteins through the Pseudomonas aeruginosa injectisome system.  Midwest Microbial Pathogenesis Meeting, West Lafayette, IN.  2009. 

Jones A, Balzer G, Yahr T, Fulcher N, Wolfgang M.  The MucA pathway contributes to reciprocal regulation of acute and chronic virulence factors in Pseudomonas aeruginosa.  Mid-Atlantic Microbial Pathogenesis Meeting, Wintergreen Conference Center, VA.  2009. 

Brutinel E, Vakulskas C, Brady K, Yahr T.  Characterization of ExsA and of ExsA-dependent promoters required for expression of the Pseudomonas aeruginosa type III secretion system.  Mol Microbiol.  2008 May. 68(3):657-71.
[Link]

Brutinel E, Yahr T.  Control of gene expression by type III secretory activity.  Curr Opin Microbiol.  2008 April. 11(2):128-33.
[Link]

Urbanowski M, Yahr T.  Limiting too much of a good thing: a negative feedback mechanism prevents unregulated translocation of type III effector proteins.  J Bacteriol.  2008 April. 190(8):2643-4.
[Link]

Brutinel E, Yahr T.  Characterization of ExsA functional domains, the Transcriptional Activator of the Pseudomonas aeruginosa Type III Secretion System.  General Meeting of the American Society for Microbiology, Boston, MA.  2008. 

Brady K, Yahr T.  Identifying intrinsic structural properties in type III secretion promoters and the role they play in ExsA-dependent transcriptional activation in Pseudomonas aeruginosa.  General Meeting of the American Society for Microbiology, Boston, MA.  2008. 

Vakulskas C, Brady K, Yahr T.  Mechanism of Transcriptional Activation by Pseudomonas aeruginosa ExsA.  Gordon Research Conference on Microbial Toxins and Pathogenesis, Andover, NH.  2008. 

Vakulskas C, Yahr T.  Mechanism of Transcriptional Activation of T3SS Promoters in Pseudomonas aeruginosa by ExsA.  General Meeting of the American Society for Microbiology, Boston, MA.  2008. 

Anderson G, Yahr T, O'Toole G.  The Pseudomonas aeruginosa Magnesium Transporter MgtE Affects Type III Secretion.  North American Cystic Fibrosis Conference, Orlando, FL.  2008. 

Urbanowski M, Brutinel E, Yahr T.  Translocation of ExsE into Chinese hamster ovary cells is required for transcriptional induction of the Pseudomonas aeruginosa type III secretion system.  Infect Immun.  2007 September. 75(9):4432-9.
[Link]

Ashare A, Monick M, Nymon A, Morrison J, Noble M, Powers L, Yarovinsky T, Yahr T, Hunninghake G.  Pseudomonas aeruginosa delays Kupffer cell death via stabilization of the X-chromosome-linked inhibitor of apoptosis protein.  J Immunol.  2007 July 1. 179(1):505-13.
[Link]

Wu Y, Xu Z, Henderson F, Ryan A, Yahr T, Mallampalli R.  Chronic Pseudomonas aeruginosa infection reduces surfactant levels by inhibiting its biosynthesis.  Cell Microbiol.  2007 April. 9(4):1062-72.
[Link]

Zheng Z, Chen G, Joshi S, Brutinel E, Yahr T, Chen L.  Biochemical characterization of a regulatory cascade controlling transcription of the Pseudomonas aeruginosa type III secretion system.  J Biol Chem.  2007 March 2. 282(9):6136-42.
[Link]

Song Y, Fairman J, Sawa T, Liggitt D, Yahr T, Wiener-Kronish J.  Cationic lipid DNA complexes (CLDC)/PcrV as a vaccine against Pseudomonas aeruginosa pneumonia.  Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), San Francisco, CA.  2007. 

Brutinel E, Vakulskas C, Yahr T.  Characterization of the ExsA Box, a Promoter Element Required for Transcription of Genes Encoding the Pseudomonas aeruginosa Type III Secretion System.  General Meeting of the American Society for Microbiology, Toronto, Canada.  2007. 

Brutinel E, Vakulskas C, Yahr T.  DNA Binding Characteristics of ExsA; The Transcriptional Regulator of Type III Secretion in Pseudomonas aeruginosa.  Phage Meeting, Madison, WI.  2007. 

Jones A, Balzer G, Yahr T, Fulcher N, Wolfgang M.  Mechanism for Reciprocal Regulation of Pseudomonas aeruginosa Virulence Factors that Contribute to Acute and Chronic Respiratory Infection.  Mid-Atlantic Microbial Pathogenesis Meeting, Wintergreen, VA.  2007. 

Yahr T, Wolfgang M.  Transcriptional regulation of the Pseudomonas aeruginosa type III secretion system.  Mol Microbiol.  2006 November. 62(3):631-40.
[Link]

Lykken G, Chen G, Brutinel E, Chen L, Yahr T.  Characterization of ExsC and ExsD self-association and heterocomplex formation.  J Bacteriol.  2006 October. 188(19):6832-40.
[Link]

Yahr T.  A critical new pathway for toxin secretion?.  N Engl J Med.  2006 September 14. 355(11):1171-2.
[Link]

Dasgupta N, Ashare A, HUNNINGHAKE G, Yahr T.  Transcriptional induction of the Pseudomonas aeruginosa type III secretion system by low Ca2+ and host cell contact proceeds through two distinct signaling pathways.  Infect Immun.  2006 June. 74(6):3334-41.
[Link]

Urbanowski M, Yahr T.  ExsE is translocated into host cells by the Pseudomonas aeruginosa type III secretion system.  General Meeting of the American Society for Microbiology, Orlando, FL.  2006. 

Dasgupta N, Ashare A, Hunninghake G, Yahr T.  Induction of the Pseudomonas aeruginosa type III secretion system by low Ca2+ and host cell contact proceeds through two distinct signaling pathways.  General Meeting of the American Society for Microbiology, Orlando, FL.  2006. 

Yahr T, Parsek M.  Pseudomonas aeruginosa.  Springer.  2006. 6:704-13.

Urbanowski M, Lykken G, Yahr T.  A secreted regulatory protein couples transcription to the secretory activity of the Pseudomonas aeruginosa type III secretion system.  Proc Natl Acad Sci U S A.  2005 July 12. 102(28):9930-5.
[Link]

Urbanowski M, Yahr T.  The ExsE regulatory protein is translocated into host cells by the Pseudomonas aeruginosa type III secretion system.  Midwest Microbial Pathogenesis Meeting, Minneapolis, MN.  2005. 

Yahr T, Greenberg E.  The genetic basis for the commitment to chronic versus acute infection in Pseudomonas aeruginosa.  Mol Cell.  2004 November 19. 16(4):497-8.
[Link]

Dasgupta N, Lykken G, Wolfgang M, Yahr T.  A novel anti-anti-activator mechanism regulates expression of the Pseudomonas aeruginosa type III secretion system.  Mol Microbiol.  2004 July. 53(1):297-308.
[Link]

Lykken G, Yahr T.  Role of an anti-activator and an anti-anti-activator in controlling expression of Pseudomonas aeruginosa type III secretion.  General Meeting of the American Society for Microbiology, New Orleans, LA.  2004. 

Dasgupta N, Wolfgang M, Yahr T.  ExsC is required for expression of the Pseudomonas aeruginosa type III secretion system.  Pseudomonas 2003 Meeting, Quebec City, Canada.  2003. 

McCaw M, Lykken G, Singh P, Yahr T.  ExsD is a negative regulator of the Pseudomonas aeruginosa type III secretion regulon.  Mol Microbiol.  2002 November. 46(4):1123-33.
[Link]

Yahr T.  ExsD is a negative regulator of type III secretion in Pseudomonas aeruginosa.  General Meeting of the American Society for Microbiology, Salt Lake City, UT.  2002. 

Yahr T, Wickner W.  Functional reconstitution of bacterial Tat translocation in vitro.  EMBO J.  2001 May 15. 20(10):2472-9.
[Link]

Yahr T, Wickner W.  Investigations of the Escherichia coli twin-arginine protein translocase.  General Meeting of the American Society for Microbiology, Orlando, FL.  2001. 

Yahr T, Wickner W.  Evaluating the oligomeric state of SecYEG in preprotein translocase.  EMBO J.  2000 August 15. 19(16):4393-401.
[Link]

Olson J, Fraylick J, McGuffie E, Dolan K, Yahr T, Frank D, Vincent T.  Interruption of multiple cellular processes in HT-29 epithelial cells by Pseudomonas aeruginosa exoenzyme S.  Infect Immun.  1999 June. 67(6):2847-54.
[Link]

Sawa T, Yahr T, Ohara M, Kurahashi K, Gropper M, Wiener-Kronish J, Frank D.  Active and passive immunization with the Pseudomonas V antigen protects against type III intoxication and lung injury.  Nat Med.  1999 April. 5(4):392-8.
[Link]

Vallis A, Finck-Barbançon V, Yahr T, Frank D.  Biological effects of Pseudomonas aeruginosa type III-secreted proteins on CHO cells.  Infect Immun.  1999 April. 67(4):2040-4.
[Link]

Vallis A, Yahr T, Barbieri J, Frank D.  Regulation of ExoS production and secretion by Pseudomonas aeruginosa in response to tissue culture conditions.  Infect Immun.  1999 February. 67(2):914-20.
[Link]

Holder I, Neely A, Yahr T, Frank D.  Genetic analysis of the type III effectors of P. aeruginosa in the burned mouse model.  General Meeting of the American Society for Microbiology, Chicago, IL.  1999. 

Frank D, Yahr T, Sawa T, Barbancon-Finck V, Wiener-Kronish J.  Type III intoxication and Pseudomonas pathogenesis.  Pseudomonas '99: Biotechnology and Pathogenesis, American Society for Microbiology, Maui, Hawaii.  1999. 

Finck-Barbançon V, Yahr T, Frank D.  Identification and characterization of SpcU, a chaperone required for efficient secretion of the ExoU cytotoxin.  J Bacteriol.  1998 December. 180(23):6224-31.
[Link]

Yahr T, Vallis A, Hancock M, Barbieri J, Frank D.  ExoY, an adenylate cyclase secreted by the Pseudomonas aeruginosa type III system.  Proc Natl Acad Sci U S A.  1998 November 10. 95(23):13899-904.
[Link]

Finck-Barbançon V, Yahr T, Frank D.  Characterization of the exoU locus from Pseudomonas aeruginosa.  General Meeting of the American Society for Microbiology, Atlanta, GA.  1998. 

Vallis A, Yahr T, Barbieri J, Frank D.  Contact-mediated regulation of ExoS production by Pseudomonas aeruginosa.  General Meeting of the American Society for Microbiology, Atlanta, GA.  1998. 

Yahr T, Vallis A, Hancock M, Frank D.  ExoY, a novel type III secreted adenylate cyclase from Pseudomonas aeruginosa.  General Meeting of the American Society for Microbiology, Atlanta, GA.  1998. 

Sawa T, Ohara M, Kurahashi K, Yahr T, Gropper M, Frank D, Wiener-Kronish J.  Pathogenesis of acute lung injury caused by Pseudomonas aeruginosa major contribution of type III secretory system.  American Federation of Biomedical Research, Biomedicine.  1998. 

Ohara M, Sawa T, Kurahashi K, Yahr T, Frank D, Wiener-Kronish J, Gropper M.  Pseudomonas aeruginosa inhibits Fc receptor-mediated phagocytosis.  American Federation of Biomedical Research, Biomedicine.  1998. 

Yahr T, Mende-Mueller L, Friese M, Frank D.  Identification of type III secreted products of the Pseudomonas aeruginosa exoenzyme S regulon.  J Bacteriol.  1997 November. 179(22):7165-8.
[Link]

Liu S, Yahr T, Frank D, Barbieri J.  Biochemical relationships between the 53-kilodalton (Exo53) and 49-kilodalton (ExoS) forms of exoenzyme S of Pseudomonas aeruginosa.  J Bacteriol.  1997 March. 179(5):1609-13.
[Link]

Vallis A, Yahr T, Frank D.  Development of in vitro methodologies to study type III-mediated translocation of Pseudomonas aeruginosa ExoS.  Midwest Microbial Pathogenesis Meeting, Ann Arbor, MI.  1997. 

Yahr T, Vallis A, Friese M, Mende-Mueller L, Frank D.  Identification and characterization of type III secreted products of the Pseudomonas aeruginosa exoenzyme S region.  Midwest Microbial Pathogenesis Meeting, Ann Arbor, MI.  1997. 

Yahr T, Friese M, Mende-Mueller L, Frank D.  Pseudomonas aeruginosa encodes homologs to the Yersinia lcrGVHyopBD locus.  General Meeting of the American Society for Microbiology, Miami Beach, FL.  1997. 

Yahr T, Goranson J, Frank D.  Exoenzyme S of Pseudomonas aeruginosa is secreted by a type III pathway.  Mol Microbiol.  1996 December. 22(5):991-1003.
[Link]

Yahr T, Barbieri J, Frank D.  Genetic relationship between the 53- and 49-kilodalton forms of exoenzyme S from Pseudomonas aeruginosa.  J Bacteriol.  1996 March. 178(5):1412-9.
[Link]

Liu S, Knight D, Yahr T, Barbieri J.  Biochemical properties of the 53-kDa form of Pseudomonas aeruginosa exoenzyme S.  General Meeting of the American Society for Microbiology, New Orleans, LA.  1996. 

Yahr T, Goranson J, Frank D.  Exoenzyme S of Pseudomonas aeruginosa is secreted by a type III pathway.  General Meeting of the American Society for Microbiology, New Orleans, LA.  1996. 

Yahr T, Goranson J, Frank D.  Exoenzyme S of Pseudomonas aeruginosa is secreted by a type III pathway.  Gordon Research Conference on Microbial Toxins and Pathogenesis, Colby-Sawyer College, NH.  1996. 

Yahr T, Hovey A, Kulich S, Frank D.  Transcriptional analysis of the Pseudomonas aeruginosa exoenzyme S structural gene.  J Bacteriol.  1995 March. 177(5):1169-78.
[Link]

Yahr T, Barbieri J, Frank D.  The genetic relationship between the 49- and 53-kDa forms of exoenzyme S.  General Meeting of the American Society for Microbiology, Washington, DC.  1995. 

Yahr T, Frank D.  Transcriptional organization of the trans-regulatory locus which controls exoenzyme S synthesis in Pseudomonas aeruginosa.  J Bacteriol.  1994 July. 176(13):3832-8.
[Link]

Kulich S, Yahr T, Mende-Mueller L, Barbieri J, Frank D.  Cloning the structural gene for the 49-kDa form of exoenzyme S (exoS) from Pseudomonas aeruginosa strain 388.  J Biol Chem.  1994 April 8. 269(14):10431-7.
[Link]

Yahr T, Frank D.  Transcriptional analysis of the exoenzyme S structural gene.  Gordon Research Conference on Microbial Toxins and Pathogenesis, Colby-Sawyer College, NH.  1994. 

Hovey A, Yahr T, Frank D.  Functional analysis of ExsA of Pseudomonas aeruginosa.  General Meeting of the American Society for Microbiology, Atlanta, GA.  1992. 

Yahr T, Frank D.  Transcriptional control of the trans-regulatory locus required for exoenzyme S synthesis in Pseudomonas aeruginosa.  Gordon Research Conference on Microbial Toxins and Pathogenesis, Colby-Sawyer College, NH.  1992. 

Yahr T, Frank D.  Transcriptional organization of the exoenzyme S trans-regulatory locus in Pseudomonas aeruginosa.  General Meeting of the American Society for Microbiology, Atlanta, GA.  1992. 

Date Last Modified: 06/07/2014 - 21:56:23