Detection and response of organisms to oxidative stress, biological iron-sulfur cluster assembly and repair
We are currently working on two interrelated projects in our lab. The first project examines the physiological response of a pathogenic bacterium to oxidative stress. The second project uses a model organism to dissect how organisms metabolize small oxidant sensitive inorganic cofactors.
1) Staphylococcus aureus is a human commensal bacterium that is naturally carried by 20-50% of the population. This bacterium can cause infections that range from relatively harmless furuncles and carbuncles to life threatening endocarditus and necrotizing pneumonia. Staphylococcus aureus infections have historically been associated with open-wounds, hospital visits, and immuno-compromised persons, but recently, infections are being seen in relatively healthy individuals that have not been associated with hospital settings (community acquired infections). Many of these infections are caused by strains of S. aureus that are resistant to nearly all commonly used antibiotics, including methicillin, greatly complicating the treatment of infections caused by this aggressive pathogen.
One research focus of our laboratory is to determine how community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) detects and responds to host defense systems. Neutrophil granulocytes are white blood cells that provide humans with a “first line” of defense against CA-MRSA infections. Neutrophils engulf and kill bacteria, in part, by bombarding them with poisonous oxidants such as bleach, superoxide, and hydrogen peroxide. Remarkably, strains of CA-MRSA can survive this attach and successfully invade host tissues. Our lab uses a variety of biochemical and genetic techniques to understand what is unique about the physiology of CA-MRSA that allows it withstand high degrees of oxidative stress. We also study how CA-MRSA detects and responds to the presence of neutrophils and oxidative stress.
2) The second focus of our work examines the metabolism of simple inorganic cofactors called iron-sulfur (Fe-S) clusters. Proteins with [Fe-S] clusters have an ever-expanding repertoire of biological functions. These metalloproteins are involved in some of the most fundamental life-sustaining processes on Earth such as biological nitrogen fixation, photosynthesis, and cellular respiration. To this end, the evolution of all life can be considered dependent on the successful and controlled synthesis and maintenance of [Fe-S] clusters. Free iron and free sulfur are toxic to cells and Iron-sulfur clusters are easily damaged by oxidants. Therefore, complex cellular machinery has evolved to tightly control the synthesis and repair of [Fe-S] clusters. Despite the recognized and central role of [Fe-S] clusters in biology, our understanding of how these inorganic cofactors are metabolized is limited by our lack of basic knowledge in which gene products control the synthesis, trafficking, and repair of these clusters and how these gene products are integrated into cellular metabolic networks.
The work on our second project aims to address remaining questions in [Fe-S] cluster metabolism and take advantage of integrative studies to uncover the biochemical function of genes of unknown function involved in [Fe-S] metabolism. Because all cells face similar challenges in integrating their metabolism and many metabolic paradigms are conserved, these studies are conducted using the model bacterium Salmonella enterica for simplicity and technical feasibility.
Mashruwala A.A., Gries C.M., Scherr T.D., Kielian T., and Boyd J.M. SaeRS is responsive to cellular respiratory status and regulates fermentative biofilm formation in Staphylococcus aureus. In revision.
Roberts C., Jasim H., Mashruwala A.A., Rosario-Cruz Z., Sause, W., Torres V.J., and Boyd J.M. The Suf iron-sulfur cluster biosynthetic system is essential for Staphylococcus aureus viability and defective Fe-S cluster biosynthesis results in broad metabolic defects and decreased survival in neutrophils. Infect Immun 2017 accepted.
Tanner A.W., Carabetta V.J., Martinie R.J., Mashruwala A.A., Boyd J.M., Krebs C., Dubnau D., The RicAFT (YmcA-YlbF-YaaT) complex carries two [4Fe-4S]2+ clusters and may respond to redox changes. Mol Microbiol 2017 PMID:28295778
Mashruwala A.A. Van de Guchte A., Boyd J.M. Impaired respiration elicits SrrAB-dependent programmed cell lysis and biofilm formation in Staphylococcus aureus. eLife. 2017 Feb. PMID:28221135
Mashruwala, A. A., Boyd J.M. The Staphylococcus aureus SrrAB regulatory system modulates hydrogen peroxide resistance factors, which imparts protection to aconitase during aerobic growth. PLoS One. 2017 Jan. PMID:28099473
Mashruwala A.M., and Boyd J.M., De novo assembly of plasmids using yeast recombinational cloning. Methods Mol. Biol. 2016 Feb PMID: 26194707
Rosario-Cruz Z. and Boyd J.M. Pysiological roles of bacillithiol in intracellular metal processing. Curr Genet. 2016 Feb. PMID: 26259870
Mashruwala A.A., Bhatt S., Poudel S., Boyd E.S., and Boyd J.M. The DUF59 containing protein SufT is involved in the maturation of iron-sulfur (FeS) proteins during conditions of high FeS cofactor demand in Staphylococcus aureus. PLoS Genetics. 2016 Aug. PMID: 27517714
Choby J.E., Mike L.A., Mashruwala A.A., Dutter B.F. Dunman, P.M., Sulikowski G.A., Boyd J.M. *, and Skaar E.P.* A small molecule inhibitor of iron-sulfur cluster assembly is toxic to Staphylococcus aureus in an Sae-dependent manner. Cell Chemical Biology 2016 Nov. PMID:27773628
Mashruwala A.A., Roberts C., Bhatt S. May K.L., Carroll R.K., Shaw L.N., Boyd J.M. Staphylococcus aureus SufT: an essential iron-sulfur cluster assembly factor in cells experiencing a high-demand for lipoic acid. Mol Microbiol. 2016 Sep. PMID: 27671355
Mashruwala A.A., Pang Y.Y., Rosario-Cruz Z., Chahal H.K., Benson M.A., Anzaldi-Mike L.L., Skaar E.P., Torres V.J., Nauseef W.M., Boyd J.M. Nfu facilitates that maturation of iron-sulfur proteins and participates in virulence in Staphylococcus aureus. Mol Microbiol. 2015. Feb. PMID: 25388433
Eveleigh D.E., Häggblom M., and Boyd J.M. The early challenges of antibiotic discovery. Microbe. 2015 Nov; 10 (11): 449-450.
Rosario-Cruz Z., Chahal H.K., Anzaldi-Mike L.L., Skaar E.P., and Boyd J.M. Bacillithiol has a role in Fe-S cluster biogenesis in Staphylococcus aureus. Mol Microbiol. 2015 Oct. PMID: 26135358
Tammy M. Joska, T.M., Mashruwala A., Boyd J.M.*, and Belden W.J*., A universal cloning method based on yeast homologous recombination that is simple, efficient, and versatile. J. Microbial Methods. Jan. 10. 2014. PMID: 2441681
White M.J., Boyd J.M., Horswill A.R., Nauseef W.M., Phosphatidylinositol-specific phospholipase C contributes to survival of Staphylococcus aureus USA300 in human blood and neutrophils. Infect. Immun. 2014. Jan 22. PMID: 24452683
Perrineau M.M, Gross J., Zelzion E., Price D.C. Levitan O., Boyd J.M., Bhattacharya D., Using natural selection to unlock the adaptive potential of microalgal genomes. PLoS One, 2014. Mar 21. PMID: 24658261.
Boyd E.S., Thomas K.M., Dai Y., Boyd J.M.*, Outten F.W.* interplay between oxygen and Fe-S cluster biogenesis: Insights from the Suf pathway. Biochemistry. 2014. Sep 11. PMID: 25153801
Yu J., Madsen M.L., Carruthers M.D., Phillips G.J., Kavanaugh J.S., Boyd J.M., Horswill A.R., Minion F.C.. Analysis of autoinducer-2 quorum sensing in Yersina pestis. Infect. Immun. 2013 Nov 15. PMID: 24247266.
Price-Whelan A., Poon C.K., Benson M.A., Eidem T.T., Roux C.M., Boyd J.M., Dunman P.M., Torres V.J., Krulwich T.A., Transcriptional profiling of Staphylococcus aureus during growth in 2 M NaCl leads to clarification of physiological roles for Kdp and Ktr K+ uptake systems. MBio. 2013 Aug 20; 4(4). PMID: 23963175.
Pang Y.Y., Schwartz J., Boyd J.M., Horswill AR, Nauseef W.M., Methionine sulfoxide reductases Protect against oxidative stress in Staphylococcus aureus encountering exogenous oxidants and human neutrophils. J Innate Immun. 2013 Nov 15. PMID: 24331053
Walker J.N., Spaulding A., Salgado-Pabón W., Schlievert P.M., Boyd J.M., Horswill A.R., The Staphylococcus aureus ArlRS two-component system is a novel regulator of agglutination and pathogenesis. PLoS Pathog. 2013 Dec;9 PMID: 24367264.
Perrineau M.M, Gross J., Zelzion E., Price D.C., Boyd J.M., Bhattacharya D., Evolution of salt tolerance in a laboratory reared population of Chlamydomonas reinhardtii. Environ Microbiology. 2013, Dec 24. PMID 24373049
Chahal H.K., Boyd J.M*, and Outten F.W*.Iron-sulfur cluster biogenesis in Archaea and Bacteria. Book Chapter in Metals and Cells. 2012. Series editors Robert Scott and Valerie Culotta.