Crosby, Heidi

Heidi Crosby

Postdoctoral Research Fellow
Address: 540 EMRB
Phone: (319) 335-7996
Email: heidi-crosby@uiowa.edu

Mentor: Alexander Horswill, PhD

Undergraduate Institution: University of Maine

PhD Institution: University of Wisconsin

Research Description

Staphylococcus aureus causes a wide range of infections, from relatively minor skin infections to life threatening conditions like sepsis, endocarditis and pneumonia. S. aureus is able to colonize and infect such diverse body sites in part because it produces many different adhesins and virulence factors. The Horswill lab is interested in how expression of these virulence factors is regulated. In my work I am studying the ArlRS two-component regulatory system, which is relatively poorly understood despite its documented links to virulence.


J.M. Mootz, M.A. Benson, C.E. Heim, H.A. Crosby, J.S. Kavanaugh, P.M. Dunman, T. Kielian, V.J. Torres, A.R. Horswill (2015). Rot is a key regulator of Staphylococcus aureus biofilm formation. Mol. Microbiol. 96, 388-404.

S.M. Daly, B.O. Elmore, J.S. Kavanaugh, K.D. Triplett, M. Figueroa, H.A. Raja, T. El-Elimat, H.A. Crosby, J.K. Femling, N.B. Cech, A.R. Horswill, N.H. Oberlies, P.R. Hall (2015). ω-Hydroxyemodin Limits Staphylococcus aureus Quorum Sensing-Mediated Pathogenesis and Inflammation. Antimicrob. Agents Chemother. 59, 2223-2235.

M.R. Kiedrowski, H.A. Crosby, F.J. Hernandez, C.L. Malone, J.O. McNamara II, A.R. Horswill (2014). Staphylococcus aureus Nuc2 is a functional, surface-attached extracellular nuclease. PLoS One 9, e95574.

H.A. Crosby, J.C. Escalante-Semerena (2014). The acetylation motif in AMP-forming acyl-CoA synthetases contains residues critical for acetylation and recognition by the protein acetyltransferase Pat of Rhodopseudomonas palustris. J. Bacteriol. 196, 1496-1504.

J.N. Walker, H.A. Crosby, A.R. Spaulding, W. Salgado-Pabon, C.L. Malone, C.B. Rosenthal, P.M. Schlievert, J.M. Boyd, A.R. Horswill (2013). The Staphylococcus aureus ArlRS two-component system is a novel regulator of agglutination and pathogenesis. PLoS Pathog. 9, e1003819.

H.A. Crosby, K.C. Rank, I. Rayment, J.C. Escalante-Semerena (2012). Structural insights into the substrate specificity of the Rhodopseudomonas palustris protein acetyltransferase RpPat: identification of a loop critical for recognition by RpPat. J. Biol. Chem. 287, 41392-41404.

H.A. Crosby*, K.C. Rank*, I. Rayment, J.C. Escalante-Semerena (2012). Structure-guided expansion of the substrate range of methylmalonyl-CoA synthetase (MatB) of Rhodopseudomonas palustris. Appl. Environ. Microbiol. 78, 6619-6629. *These authors contributed equally.

H.A. Crosby, D.A. Pelletier, G.B. Hurst, J.C. Escalante-Semerena (2012). System-wide studies of N-lysine acetylation in Rhodopseudomonas palustris reveals substrate specificity of protein acetyltransferases. J. Biol. Chem. 287, 15590-15601.

C.H. Chan, J. Garrity, H.A. Crosby, J.C. Escalante-Semerena (2011). In Salmonella enterica, the sirtuin-dependent protein acylation/deacylation system maintains energy homeostasis during growth on low concentrations of acetate. Mol. Microbiol. 80, 168-183.

H.A. Crosby, E.K. Heiniger, C.S. Harwood, J.C. Escalante-Semerena (2010). Reversible Nε-lysine acetylation regulates the activity of acyl-CoA synthetases involved in anaerobic benzoate catabolism in Rhodopseudomonas palustris. Mol. Microbiol. 76, 874-888.

A. Kappler, C.M. Johnson, H.A. Crosby, B.L. Beard, D.K. Newman (2010). Evidence for equilibrium iron isotope fractionation by nitrate-reducing iron(II)-oxidizing bacteria. Geochim. Cosmochim. Acta. 74, 2826-2842.

E.A. Felnagle, M.R. Rondon, A.D. Berti, H.A. Crosby, M.G. Thomas (2007). Identification of the biosynthetic gene cluster and an additional gene for resistance to the antituberculosis drug capreomycin. Appl. Environ. Microbiol. 73, 4162-4170.

H.A. Crosby, E.E. Roden, C.M. Johnson, B.L. Beard (2007). The mechanisms of Fe isotope fractionation produced during dissimilatory Fe(III) reduction by S. putrefaciens and G. sulfurreducens. Geobiology 5, 169-189.

H.A. Crosby, C.M. Johnson, E.E. Roden, B.L. Beard (2005). Coupled Fe(II)-Fe(III) and atom exchange as a mechanism for Fe isotope fractionation during dissimilatory iron oxide reduction. Environ. Sci. & Technol. 39, 6698-6704.

G.M. King, H.A. Crosby (2002). Impacts of plant roots on soil CO cycling and soil-atmosphere CO exchange. Global Change Biol. 8:1085-1093.


  • American Heart Association Postdoctoral Fellowship, 2015-2017
  • University of Wisconsin-Madison Dept of Bacteriology Chair's Award, 2012
  • Ira L. Baldwin Predoctoral Fellowship, University of Wisconsin-Madison Dept of Bacteriology, 2011
  • NIH Biotechnology Training Grant, 2007-2011
  • NSF Graduate Research Fellowship, 2004-2007