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Raskovic D, Alvarado G, Hines KM, Xu L, Gatto C, Wilkinson BJ, Pokorny A. Growth of Staphylococcus aureus in the presence of oleic acid shifts the glycolipid fatty acid profile and increases resistance to antimicrobial peptides. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.03.592415. [PMID: 38746422 PMCID: PMC11092785 DOI: 10.1101/2024.05.03.592415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Staphylococcus aureus readily adapts to various environments and quickly develops antibiotic resistance, which has led to an increase in multidrug-resistant infections. Hence, S. aureus presents a significant global health issue and its adaptations to the host environment are crucial for understanding pathogenesis and antibiotic susceptibility. When S. aureus is grown conventionally, its membrane lipids contain a mix of branched-chain and straight-chain saturated fatty acids. However, when unsaturated fatty acids are present in the growth medium, they become a major part of the total fatty acid composition. This study explores the biophysical effects of incorporating straight-chain unsaturated fatty acids into S. aureus membrane lipids. Membrane preparations from cultures supplemented with oleic acid showed more complex differential scanning calorimetry scans than those grown in tryptic soy broth alone. When grown in the presence of oleic acid, the cultures exhibited a transition significantly above the growth temperature, attributed to the presence of glycolipids with long-chain fatty acids causing acyl chain packing frustration within the bilayer. Functional aspects of the membrane were assessed by studying the kinetics of dye release from unilamellar vesicles induced by the antimicrobial peptide mastoparan X. Dye release was slower from liposomes prepared from cells grown in oleic acid-supplemented cultures, suggesting that changes in membrane lipid composition and biophysics protect the cell membrane against peptide-induced lysis. These findings underscore the intricate relationship between the growth environment, membrane lipid composition, and the physical properties of the bacterial membrane, which should be considered when developing new strategies against S. aureus infections.
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Affiliation(s)
- Djuro Raskovic
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina, United States of America
| | - Gloria Alvarado
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Kelly M Hines
- Department of Chemistry, University of Georgia, Athens, Georgia, United States of America
| | - Libin Xu
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, United States of America
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Brian J Wilkinson
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Antje Pokorny
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina, United States of America
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Zhang Y, Chung WK, Moon SH, Lee JG, Om AS. Comparison of Antibacterial Activities of Korean Pine ( Pinus densiflora) Needle Steam Distillation Extract on Escherichia coli and Staphylococcus aureus Focusing on Membrane Fluidity and Genes Involved in Membrane Lipids and Stress. Molecules 2023; 29:165. [PMID: 38202748 PMCID: PMC10779765 DOI: 10.3390/molecules29010165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/22/2023] [Accepted: 12/23/2023] [Indexed: 01/12/2024] Open
Abstract
The antibacterial activity and mechanism of Pinus densiflora extracts against Escherichia coli and Staphylococcus aureus were investigated. The growth inhibition tests of paper diffusion and optical density exhibited that the extracts have potent antibacterial potentials against foodborne pathogens. The measurement of membrane fluidity by fluorescence polarization has indicated that one of the antibacterial mechanisms involves the disruption of membrane integrity resulting in an increase in the membrane fluidity in both of E. coli and S. aureus. The alteration of fatty acid composition was accompanied by the disturbance of membranes thus shifting the proportion of saturated verses unsaturated fatty acids or trans fatty acids from 1.27:1 to 1.35:1 in E. coli and 1.47:1 to 2.31:1 in S. aureus, most likely to compensate for the increased membrane fluidity by means of a higher proportion of saturated fatty acids which is known to render rigidity in membranes. Realtime q-PCR (polymerase chain reaction) analysis of fatty acid synthetic genes and bacterial stress genes revealed that there was minimal influence of P. densiflora extracts on fatty acid genes except for fab I and the stress rpos in E. coli, and relatively greater impact on fatty acid genes and the stress sigB in S. aureus.
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Affiliation(s)
| | | | | | | | - Ae-Son Om
- Department of Food and Nutrition, Hanyang University, Seoul 04736, Republic of Korea; (Y.Z.); (W.-K.C.); (S.-H.M.); (J.-G.L.)
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