https://www.beaversresearchgroup.com/members daily 0.75 2026-03-31 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/74e828e5-e08f-480c-b930-f6404958a621/Will+2025.jpeg Current - Will Beavers, Ph.D. Principal Investigator Postdoctoral Fellowship, Microbiology Vanderbilt University Medical Center Ph.D., Chemistry Vanderbilt University M.S., Chemistry Northeastern University B.S., cum laude, Chemistry Old Dominion University Will grew up on a family farm in the Loudoun Valley of Virginia. After earning a B.S. in chemistry, he moved to Boston where he worked at the Dana-Farber Cancer Institute while getting an M.S. in chemistry. After many years in Boston he moved to Nashville for further graduate school and a postdoctoral fellowship. The Beavers Research Group was established in 2021 at LSU in the School of Veterinary Medicine. Will’s research interests lie at the interface of chemistry and microbiology, specifically focused on antibacterial protein post-translational modifications at the host-pathogen interface. When not in lab, Will spends most of his time endurance running or exploring Baton Rouge with his wife, three daughters, and Waldo the chihuahua. wbeavers@lsu.edu https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/d5a8da1f-84e0-404a-809d-4f8c38f1788b/Bennett.png Current - Bennett Blank LSU President’s Alumni Scholar Bennett was born in Baton Rouge, Louisiana. He grew an interest in science during high school and is now studying Biological Science at LSU on a Pre-Med track. He was captain of the Powerlifting team in high school and a member of the French and Creative Writing clubs. Bennett is a President's Alumni Scholar at LSU. In his free time, he likes to play video games and listen to music. Bennett plans to study medicine and travel the world. bblank8@lsu.edu https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/416a02b5-8ae6-47d1-afb6-28a8d178d0d8/Elliott.png Current - Elliott Collins Undergraduate Researcher co-mentored with Dr. Juan Martinez Elliott Collins was born and raised in San Jose, California, before later moving to Northern Virginia. In high school, he explored robotics, nurturing his curiosity for science and technology. Driven by his interest in microbiology, he is eager to pursue a career in medicine as an infectious diseases physician. In his free time, Elliott enjoys exploring aerial photography and spending time at the climbing gym. ecoll39@lsu.edu https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/469254c3-f684-4d96-922c-f36773ac1d85/Emily.jpg Current - Emily Glazner Undergraduate Researcher Emily is from New Orleans, where she attended St. Mary's Dominican High School. She has always had a strong interest in science, especially organic chemistry and biochemistry. She is currently a junior at Louisiana State University, majoring in biochemistry on the pre-med track. She intends to pursue a career in dermatology, with a particular interest in Mohs surgery, a tissue-preserving procedure used to remove skin cancer. This interest developed after seeing her father undergo multiple treatments for skin cancer, which inspired her to learn more about the field and its impact on patients’ lives. In her free time, Emily enjoys reading books with engaging plot twists and spending time with her friends. Emily.Glazner@lsu.edu https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/a2b91bc1-ce65-4619-a70a-3e8563a1fa43/Heather+Green.jpg Current - Heather Green, B.S. Huel D. Perkins Doctoral Fellow B.S., Biochemistry Louisiana State University Heather was raised in Erath, Louisiana, a small town about an hour and a half south of Baton Rouge. She developed a strong interest in biology during high school and pursued this interest as a biochemistry major at LSU. During this time, she worked as an undergraduate researcher studying the kinetic and antibacterial properties of enzymatic inhibitors. As a Ph.D. Student in the Department of Pathobiological Sciences, Heather is excited to uncover novel mechanisms employed by Staphylococcus aureus to avoid killing at the host-pathogen interface to inform the design of more effective antimicrobials. Outside of the lab, she enjoys crocheting and other crafts, playing Stardew Valley, and hanging out with her cat, Buddy. hgree18@lsu.edu https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/9ce44ab7-a4c0-4540-84ad-409f8bad63ab/Brooke.jpg Current - Brooke LeBreton LSU Flagship Scholar Brooke grew up in Slidell, Louisiana - just outside of New Orleans. In high school, Brooke worked as a recall dental assistant at a local pediatric dentist’s office and interned at an urgent care in town. She was involved in her high school’s student council as senior class president and was captain of the swim team. Brooke is an LSU Flagship Scholar and her major is microbiology. In Brooke’s free time, she makes earrings for her Instagram jewelry boutique. blebre1@lsu.edu https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/9cd107a5-ad99-48c5-b5c0-9e0f81b885b1/Grace+Ross.jpeg Current - D. Grace Ross, B.S. Ph.D. Student B.S., Biology SUNY Oswego Grace was born and raised in Queens, New York. From an early age, she developed an interest in public health and infectious diseases and discovered her passion for biomedical research while studying gut microbial genetics and metabolism in Drosophila during her undergraduate studies at SUNY Oswego. In the summer of 2024, she moved to Baton Rouge to pursue a Ph.D. in Pathobiological Sciences at the LSU School of Veterinary Medicine. Grace is eager to explore genetic and metabolic research on Staphylococcus aureus, specifically investigating the biological mechanisms that protect against lipid electrophiles and other membrane stressors. You’ll most likely find her in the lab with headphones on, listening to music at a dangerously loud volume. Outside the lab, she enjoys building in The Sims 4 and Minecraft, reading fiction novels, and strength training at the gym. dross28@lsu.edu https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/04a60d0a-8c47-4fea-b903-d0056cf1f9eb/tempImageojOqkl.jpg Current - Alex R. Stackhouse, B.S. Ph.D. Candidate B.S., Biochemistry Henderson State University Alex was born and grew up in central Arkansas. When he was in high school, he started to gain an interest in science, which led him to study biochemistry as an undergraduate. There he took an interest in infectious diseases, and in the fall of 2021, he was accepted as a graduate student at the LSU School of Veterinary Medicine studying Pathobiology. Alex has an interest in studying host-pathogen interactions from a molecular standpoint, and wants to continue to use, and improve his knowledge of biochemistry. Outside of class and lab, Alex likes to powerlift, explore to find hole in the wall restaurants, and when he gets the chance, practice his musical instruments. astack8@lsu.edu https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/2380494d-5275-443a-9826-ea6ec98cb522/Wyatt.jpg Current - Wyatt Wittliff, B.S. Research Associate 1 B.S., Biological Engineering Louisiana State University Wyatt was born and raised in New Orleans, Louisiana. He moved to Baton Rouge to study biological engineering at LSU, where he has since graduated. He started and captained the robotics team at his high school. Wyatt spends most of his free time cooking or playing dungeons & dragons with his friends. He plans to do research to expand his knowledge of different parts of the field of science. wwittl1@lsu.edu https://www.beaversresearchgroup.com/contact daily 0.75 2026-02-26 https://www.beaversresearchgroup.com/news daily 0.75 2026-03-30 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/7e535ed6-791d-4623-b6c2-fbee760640f0/LSU-2025-Awards-Ceremony-028.jpeg News - Beavers Research Group awarded the 2025 LSU Alumni Association Rising Faculty Research Award April 22, 2025 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/9ec59589-f475-496d-b76f-1cb75a765784/IMG_5544.jpeg News - Investing in Discovery: How NIH Funding Powers Scientific Progress and Economic Growth February 25, 2025 William Beavers, PhD https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/04a60d0a-8c47-4fea-b903-d0056cf1f9eb/tempImageojOqkl.jpg News - Alex Stackhouse passes his General Exam December 7, 2023 Alex Stackhouse passed his General Exam, making him the first PhD Candidate in the Beavers Research Group. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/672998c5-b570-4737-918e-3a9e6802be0b/IMG_2045.jpeg News - Alex Stackhouse’s talk wins 2nd place. May 24, 2023 Ph.D. student Alex Stackhouse won second place for his talk, “Cell wall mutations modulate arachidonic acid resistance in Staphylococcus aureus,“ at the annual Department of Pathobiological Sciences Graduate Student Symposium. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/70ad5712-24ea-4b6f-9c05-1c0b5180a167/IMG_1872.jpeg News - Kirsten Rico’s poster wins 4th place. March 1, 2023 Summer Scholar Kirsten Rico won 4th place for her poster, “Elucidating the mechanisms of polyunsaturated fatty acid killing of S. aureus small colony variants,” at the annual Phi Zeta Research Emphasis Day. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/a9eacdbf-5c74-4234-b6bf-909d7c6f6f34/Asif+Iqbal.jpg News - Asif Iqbal, Ph.D. joins the group. February 6, 2023 Asif joined the group as a Postdoctoral Fellow following the completion of his Ph.D. in the laboratory of Dr. Bill Doerrler. Asif’s research will define the mechanism of the crosstalk between polyunsaturated fatty acid resistance and antibiotic resistance in Staphylococcus aureus. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/fdbef710-27c7-473c-b166-3b4867d9b805/tempImage3qtLDD.jpg News - Beavers Group Turns 1! November 1, 2022 The Beavers Research Group celebrated our first anniversary, complete with office decorations while Will was at a conference, including a miniature beaver working hard to build a desk dam. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/ea308f1c-badf-4669-bb03-7530d2d0e8e1/Kaegan.jpg News - Kaegan Hill joins the group. September 27, 2022 Kaegan Hill joined the group as a Stamps Scholar and a President’s Future Leaders in Research Scholar. Kaegan’s undergraduate research will focus on the role of polyunsaturated fatty acids in controlling Staphylococcus aureus infections. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/5fce5491-2d23-42d3-b36f-452417369300/NMV_WebsiteIntro.JPG News - Nora Villafuerte joins the group. August 1, 2022 Nora Villafuerte joined the group from Baylor College of Medicine as a Research Associate 3. She will serve as Lab Manager while also working to define how polyunsaturated fatty acids kill Staphylococcus aureus. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/f487e75f-5091-4fa0-a9b6-f38bbc7e8d88/tempImagenR1CsQ.jpg News - Beavers Group photo June 3, 2022 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/04a60d0a-8c47-4fea-b903-d0056cf1f9eb/tempImageojOqkl.jpg News - Alex Stackhouse joins the group. May 23, 2022 Alex Stackhouse joined the group as a Ph.D. student. Alex will work to identify and characterize the protein targets of lipid electrophiles in Staphylococcus aureus. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/0cd6d559-01a3-41ad-9848-84a0f573997b/Aravinthan.jpg News - Aravinthan Vignarajah joins the group. May 20, 2022 Aravinthan Vignarajah joined the group as a Ph.D. student. Aravinthan will further define the contribution of peptide methionine sulfoxide reductases to Staphylococcus aureus pathogenesis. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/87177eb9-5ba8-4faa-8c4a-db448806c6a8/Kirsten.jpg News - Kirsten Rico joins the group. May 17, 2022 Kirsten Rico joined the group as a part of the School of Veterinary Medicine Summer Scholars Program. Kirsten will define the mechanism of S. aureus killing by polyunsaturated fatty acids. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/f80d3076-cffc-4ba7-b4eb-980ec59ae206/tempImageaMTsvf.jpg News - Staphylococcus aureus grows again! January 18, 2022. The inaugural plate of S. aureus USA300 LAC was grown in the Beavers Research Group. https://www.beaversresearchgroup.com/projects daily 0.75 2024-03-18 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/58f34a19-694d-449f-8f75-ee8ce542518f/tempImagepubM19.jpg Projects - Staphylococcus aureus Staphylococcus aureus can infect every niche of the human host and is the leading cause of Gram-positive sepsis. In the United States, there are over 900,000 severe S. aureus infections annually of which nearly 10 % are caused by strains that are resistant to commonly used antibiotics. Both the CDC and WHO have identified S. aureus as a pathogen that necessitates the development of more effective treatments. We use a combination of analytical chemistry, bacterial pathogenesis, bacteriology, and chemical biology techniques to better understand how the vertebrate host kills S. aureus and how S. aureus evades killing by the host. We identify S. aureus pathways targeted by aberrant post-translational modifications at the host-pathogen interface. These pathways represent potential therapeutic weaknesses in S. aureus and following validation they will be targeted with novel antimicrobial compounds that sensitize S. aureus to killing by the host’s immune system. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/36296f92-efbc-4885-9d32-649e50b5ac63/Slide1.jpeg Projects - Polyunsaturated Fatty Acids When immune cells of the vertebrate host encounter S. aureus they release polyunsaturated fatty acids (PUFA), which are bactericidal against S. aureus. PUFAs are incorporated into S. aureus phospholipids where they are oxidized to various lipid electrophiles. Nucleophilic functional groups of S. aureus macromolecules react with these lipid electrophiles with potentially deleterious effects. We are interested in defining the role of lipid electrophile post-translational modifications at the host-pathogen interface. Active projects in the group seek to discover the identity of the electrophiles, the S. aureus pathways responsible for electrophile generation, and the S. aureus proteins targeted by electrophiles. Finally, we aim to define the role of lipid electrophiles in S. aureus pathogenesis, and determine if this strategy can be used as an effective antimicrobial therapy. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/4abbf211-d6e4-46b5-870c-060d285cd462/Slide6.jpeg Projects https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/20b0cff4-2d1f-45c2-b58a-4de1e9ee2493/Slide5.jpeg Projects https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/3fb15d2e-6333-4365-968f-0ddb1ec6228a/Slide4.jpeg Projects https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/408d7368-6d4b-4d66-b8b0-18690b86501b/Slide2.jpeg Projects - Methionine Sulfoxide Reductases The sulfur containing amino acids, cysteine and methionine, are susceptible to oxidation. Unlike cysteine, the sulfur atom of methionine does not have a direct role in catalysis, but contributes to protein stability through hydrophobic and sulfur-π interactions with other amino acids. Therefore, methionine oxidation can have deleterious effects on S. aureus enzymes. The methionine sulfoxide reductases (Msr) evolved to repair oxidized methionine (methionine sulfoxide), preventing the need to resynthesize oxidized proteins de novo. Staphylococci are unique in having four, non-redundant Msr enzymes. Active projects in the group seek to identify the substrate specificity of each Msr, define the regulation of each Msr, and determine the role of each Msr in S. aureus pathogenesis. Understanding how S. aureus uses these enzymes to subvert host antimicrobial strategies will inform future antimicrobial design to render S. aureus more vulnerable to oxidative killing. https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/ea9c48fb-6d46-496b-aaa1-3840479cf1d8/Slide8.jpeg Projects https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/0617eb98-7680-471f-a56c-b99704eafe5f/Slide9.jpeg Projects https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/c1494bc0-d467-4db6-bed4-d07cbad4a61f/Slide10.jpeg Projects https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/22fff62b-a69b-4164-807f-461fa7483e1c/Shimadzu.jpg Projects - LSU-SVM Mass Spectrometry Resource Center The LSU SVM Mass Spectrometry Resource Center, which houses a state-of-the-art mass spectrometry system: the Shimadzu 8060NX triple quadrupole mass spectrometer with a Shimadzu Nexera XS 40 series UHPLC, is now accepting samples. This instrumentation is capable of performing small molecule identification and quantification, lipidomics, and metabolomics at femotmole levels from complex biological matrices. Please contact wbeavers@lsu.edu with any project inquiries. https://www.beaversresearchgroup.com/publications daily 0.75 2026-02-26 https://www.beaversresearchgroup.com/openings daily 0.75 2024-03-18 https://www.beaversresearchgroup.com/polyunsaturated-fatty-acids daily 0.75 2022-05-21 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/20b0cff4-2d1f-45c2-b58a-4de1e9ee2493/Slide5.jpeg polyunsaturated fatty acids https://www.beaversresearchgroup.com/msr-knockout daily 0.75 2022-05-21 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/ea9c48fb-6d46-496b-aaa1-3840479cf1d8/Slide8.jpeg msr knockout - Methionine sulfoxide reductases (Msr) repair oxidized methionine residues (methionine sulfoxide) in S. aureus. (A) All four Msr enzymes were deleted in USA300 LAC to create Δmsr and the Msr enzymatic activity of the strains was quantified. No activity is detected in the Δmsr strain, indicating that there are no additional Msr enzymes in S. aureus. ( B) Neutrophils generate HOCl, a bactericidal oxidant, through the enzymatic activity of myeloperoxidase. USA300 wildtype and Δmsr were treated with HOCl in vitro. Using Ox4, a probe that reacts with methionine, but not methionine sulfoxide, the extent of methionine oxidation was measured by attaching biotin through Cu-mediated click chemistry to Ox4 modified proteins, followed SDS-PAGE, and visualization with a streptavidin-based fluorophore. A darker signal indicates less methionine oxidation, and as expected, Δmsr, which is unable to repair methionine sulfoxide has increased methionine oxidation compared to USA300 wild type. https://www.beaversresearchgroup.com/whole-blood-killing daily 0.75 2022-05-21 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/c1494bc0-d467-4db6-bed4-d07cbad4a61f/Slide10.jpeg whole blood killing - Methionine sulfoxide reductases (Msr) protect S. aureus against neutrophil killing and human whole blood killing, but not against murine whole blood killing. (A) USA300 wildtype and Δmsr were incubated with polymorphonuclear leukocytes (PMN) (MOI = 1) isolated from human blood. Killing by PMNs was assessed by plating for colony forming units (CFU) following the co-incubation. (B) USA300 wildtype and Δmsr were incubated with PMNs (MOI = 1) isolated from murine bone marrow. Killing by PMNs was assessed by plating for CFU following the co-incubation. USA300 wildtype recovers from co-incubation with PMNs better than Δmsr because Δmsr cannot repair oxidized methionine residues and must resynthesize oxidized proteins de novo before growth can resume. Both human and murine PMNs exhibit similar killing phenotypes when co-incubated with S. aureus, indicating no species differences in PMN function against S. aureus. ( C) USA300 wildtype and Δmsr were incubated with human whole blood and killing was assessed by plating for CFU. (D) USA300 wildtype and Δmsr were incubated with murine whole blood and killing was assessed by plating for CFU. Human whole blood kills Δmsr better than USA300 wildtype at all of the time points tested, but there is no difference between the strains in murine whole blood. Humans have 10-fold greater circulating neutrophils than mice, and this demonstrates that potentially the deficiency in circulating neutrophils in murine blood renders the Msr enzymes less important for pathogenesis in a murine host, consistent with our other findings. https://www.beaversresearchgroup.com/pufa-scheme daily 0.75 2022-05-21 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/36296f92-efbc-4885-9d32-649e50b5ac63/Slide1.jpeg PUFA scheme - Polyunsaturated fatty acids (PUFA) are highly abundant at the host-pathogen interface. Many immune cells, including macrophages, dendritic cells, and neutrophils, release millimolar concentrations of arachidonic acid (AA) upon activation by pathogen-associated molecular patterns. AA is one of the most abundant fatty acids at the host-pathogen interface. Most free AA is converted to bioactive lipid signaling molecules like prostaglandins through the enzymatic activity of the cyclooxygenase enzymes or to leukotrienes and hydroxyeicosatetraenoic acids (HETEs) through the enzymatic activity of leukotrienes. AA is also susceptible to non-enzymatic, autoxidation forming isoprostanes and HETEs, which are structurally similar to enzymatically derived prostaglandins and HETEs, respectively. Additionally, autoxidation of AA produces various lipid electrophiles, including aldehydes, γ-ketoaldehydes, and α,β-unsaturated carbonyls. These lipid electrophiles react with nucleophilic groups on cellular macromolecules, potentially altering the biological function of the target molecules. We discovered that AA is bactericidal against S. aureus through a lipid peroxidation mechanism and that preventing lipid electrophile formation abrogates the toxicity of AA against S. aureus. Future studies in the lab will further define the role of bactericidal lipid electrophiles in controlling S. aureus infections. https://www.beaversresearchgroup.com/isolevuglandin-scavengers daily 0.75 2022-05-21 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/3fb15d2e-6333-4365-968f-0ddb1ec6228a/Slide4.jpeg isolevuglandin scavengers - (A) Arachidonic acid (AA) kills S. aureus through a lipid peroxidation mechanism. One specific class of lipid electrophiles generated during lipid peroxidation are γ-ketoaldehydes such as isolevuglandins (IsoLG). These dicarbonyl lipid electrophiles are extremely reactive with primary amines including the ε-amine of lysine. Due to the pathogology associated with γ-ketoaldehydes in mammals, many tools were developed to facilitate their study. One set of tools are dicarbonyl scavengers derived from the pyridoxamine scaffold, which are 1000X more reactive with IsoLG than the ε-amine of lysine. (B) We used two different dicarbonyl scavengers to assess if IsoLG are being formed in S. aureus, and to determine where in the cell they are formed. Pyridoxamine (PM) and 5’-O-pentyl-pyridoxamine (PnPM) are equally reactive with IsoLG, but PM is hydrophilic and thus membrane impermeable, while PnPM readily crosses the membrane barrier due to its hydrophobicity. PnPM protects S. aureus from killing by AA, while PM does not, indicating that IsoLGs are bactericidal and that that autoxidation of AA occurs inside of the S. aureus cell. (C) An antibody that binds to IsoLG protein post-translational modifications (PTM) shows that IsoLG PTMs are not present in S. aureus before treatment with AA. IsoLG PTMs become abundant across a large swath of the S. aureus proteome following AA treatment. Co-treatment of S. aureus with AA and PnPM eliminates the IsoLG PTMs, correlating with the protection from the bactericidal activity of AA by PnPM seen in panel B. Together, this figure demonstrates that AA undergoes autoxidation in S. aureus, and that the lipid electrophiles generated during autoxidation are responsible for the bactericidal activity of AA against S. aureus. https://www.beaversresearchgroup.com/hocl-killing daily 0.75 2022-05-21 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/0617eb98-7680-471f-a56c-b99704eafe5f/Slide9.jpeg HOCl killing - Neutrophils generate HOCl, a bactericidal oxidant, through the enzymatic activity of myeloperoxidase. HOCl oxidizes methionine residues to methionine sulfoxide. (A) Repair of methionine sulfoxide by the methionine sulfoxide reductases (Msr) is critical for the survival of S. aureus. USA300 wildtype and Δmsr were treated with and with out HOCl. Growth was monitored by optical density at 600 nm. While HOCl attenuates the growth of both strains, no growth of the the Δmsr strain is visible 24 h following HOCl treatment. (B) To determine if the phenotype observed in panel A is bacteriostatic or bactericidal, USA300 wildtype and Δmsr were treated with multiple concentrations of HOCl. After incubation, the samples were dilution plated on solid medium to enumerate viable bacteria. HOCl kills more than 1000-fold more bacteria of the Δmsr strain compared to USA300 wildtype. In total, these data demonstrate the critical role of the Msr enzymes in protecting S. aureus from oxidative killing. https://www.beaversresearchgroup.com/lipid-peroxidation daily 0.75 2022-05-21 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/4abbf211-d6e4-46b5-870c-060d285cd462/Slide6.jpeg lipid peroxidation https://www.beaversresearchgroup.com/msr-scheme daily 0.75 2022-05-21 https://images.squarespace-cdn.com/content/v1/61e59c77a33109732f1258b6/408d7368-6d4b-4d66-b8b0-18690b86501b/Slide2.jpeg Msr scheme - S. aureus is adept at avoiding and repairing oxidative damage to its cellular macromolecules caused by the host. Repair of oxidative damage to proteins provides a competitive advantage to the organism because if repair were not possible, damaged proteins would need to be resynthesized de novo following each deleterious oxidation event. This is a time and energy intensive process, especially when S. aureus is attempting to colonize and survive many other host antimicrobial stressors. The sulfur containing amino acids, cysteine and methionine, are particularly susceptible to oxidation. The thioredoxin and thioredoxin reductase system repairs oxidized cysteines, while the methionine sulfoxide reductases (Msr) revert methionine sulfoxide to methionine. S. aureus is unique among bacterial pathogens in that it has four Msr enzymes (MsrA1, MsrA2, MsrA3, and MsrB). Methionine sulfoxide is a chiral molecule, and the A reductases have activity toward the (S)-epimer, while the B reductase has activity toward the (R)-epimer. Why S. aureus has three A reductases and one B reductase is unknown, but the enzymes are not fully redundant. Current projects in the lab seek to define the differences between the enzymes and discover their unique roles in S. aureus pathogenesis. https://www.beaversresearchgroup.com/members-1 daily 0.75 2026-02-26 https://www.beaversresearchgroup.com/home daily 1.0 2022-01-27