1
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Fletcher JR, Hansen LA, Martinez R, Freeman CD, Thorns N, Villareal AR, Penningroth MR, Vogt GA, Tyler M, Hines KM, Hunter RC. Commensal-derived short-chain fatty acids disrupt lipid membrane homeostasis in Staphylococcus aureus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.12.607382. [PMID: 39185181 PMCID: PMC11343118 DOI: 10.1101/2024.08.12.607382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
The role of commensal anaerobic bacteria in chronic respiratory infections is unclear, yet they can exist in abundances comparable to canonical pathogens in vivo. Their contributions to the metabolic landscape of the host environment may influence pathogen behavior by competing for nutrients and creating inhospitable conditions via toxic metabolites. Here, we reveal a mechanism by which the anaerobe-derived short chain fatty acids (SCFAs) propionate and butyrate negatively affect Staphylococcus aureus physiology by disrupting branched chain fatty acid (BCFA) metabolism. In turn, BCFA impairment results in impaired growth, diminished expression of the agr quorum sensing system, as well as increased sensitivity to membrane-targeting antimicrobials. Altered BCFA metabolism also reduces S. aureus fitness in competition with Pseudomonas aeruginosa, suggesting that airway microbiome composition and the metabolites they produce and exchange directly impact pathogen succession over time. The pleiotropic effects of these SCFAs on S. aureus fitness and their ubiquity as metabolites in animals also suggests that they may be effective as sensitizers to traditional antimicrobial agents when used in combination.
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Affiliation(s)
- Joshua R. Fletcher
- Department of Microbiology & Immunology, University of Minnesota, Minneapolis, MN 55455
- Department of Population Health and Pathobiology, North Carolina State University College of Veterinary Medicine, Raleigh, NC 27695
| | - Lisa A. Hansen
- Department of Microbiology & Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203
| | - Richard Martinez
- Department of Microbiology & Immunology, University of Minnesota, Minneapolis, MN 55455
| | | | - Niall Thorns
- Department of Microbiology & Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203
| | - Alex R. Villareal
- Department of Microbiology & Immunology, University of Minnesota, Minneapolis, MN 55455
| | | | - Grace A. Vogt
- Department of Microbiology & Immunology, University of Minnesota, Minneapolis, MN 55455
| | - Matthew Tyler
- Department of Otolaryngology, University of Minnesota, Minneapolis, MN, 55455
| | - Kelly M. Hines
- Department of Chemistry, University of Georgia, Athens, GA, 30602
| | - Ryan C. Hunter
- Department of Microbiology & Immunology, University of Minnesota, Minneapolis, MN 55455
- Department of Microbiology & Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203
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2
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Kader Chowdhury QMM, Islam S, Narayanan L, Ogunleye SC, Wang S, Thu D, Freitag NE, Lawrence ML, Abdelhamed H. An insight into the role of branched-chain α-keto acid dehydrogenase (BKD) complex in branched-chain fatty acid biosynthesis and virulence of Listeria monocytogenes. J Bacteriol 2024; 206:e0003324. [PMID: 38899896 PMCID: PMC11270904 DOI: 10.1128/jb.00033-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024] Open
Abstract
Listeria monocytogenes is a foodborne bacterial pathogen that causes listeriosis. Positive regulatory factor A (PrfA) is a pleiotropic master activator of virulence genes of L. monocytogenes that becomes active upon the entry of the bacterium into the cytosol of infected cells. L. monocytogenes can survive and multiply at low temperatures; this is accomplished through the maintenance of appropriate membrane fluidity via branched-chain fatty acid (BCFA) synthesis. Branched-chain α-keto acid dehydrogenase (BKD), which is composed of four polypeptides encoded by lpd, bkdA1, bkdA2, and bkdB, is known to play a vital role in BCFA biosynthesis. Here, we constructed BKD-deficient Listeria strains by in-frame deletion of lpd, bkdA1, bkdA2, and bkdB genes. To determine the role in in vivo and in vitro, mouse model challenges, plaque assay in murine L2 fibroblast, and intracellular replication in J744A.1 macrophage were conducted. BKD-deficient strains exhibited defects in BCFA composition, virulence, and PrfA-regulon function within the host cells. Transcriptomics analysis revealed that the transcript level of the PrfA-regulon was lower in ΔbkdA1 strain than those in the wild-type. This study demonstrates that L. monocytogenes strains lacking BKD complex components were defective in PrfA-regulon function, and full activation of wild-type prfA may not occur within host cells in the absence of BKD. Further study will investigate the consequences of BKD deletion on PrfA function through altering BCFA catabolism.IMPORTANCEListeria monocytogenes is the causative agent of listeriosis, a disease with a high mortality rate. In this study, we have shown that the deletion of BKD can impact the function of PrfA and the PrfA-regulon. The production of virulence proteins within host cells is necessary for L. monocytogenes to promote its intracellular survival and is likely dependent on membrane integrity. We thus report a link between L. monocytogenes membrane integrity and the function of PrfA. This knowledge will increase our understanding of L. monocytogenes pathogenesis, which may provide insight into the development of antimicrobial agents.
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Affiliation(s)
- Q M Monzur Kader Chowdhury
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - Shamima Islam
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - Lakshmi Narayanan
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - Seto C. Ogunleye
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - Shangshang Wang
- Department of Animal and Dairy Sciences, Mississippi State University, Mississippi State, Mississippi, USA
| | - Dinh Thu
- Tyson Foods, R&D Ingredient Solutions, Springdale, Arkansas, USA
| | - Nancy E. Freitag
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Mark L. Lawrence
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, USA
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3
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Barbarek SC, Shah R, Paul S, Alvarado G, Appala K, Phillips C, Henderson EC, Strandquist ET, Pokorny A, Singh VK, Gatto C, Dahl JU, Hines KM, Wilkinson BJ. Lipidomics of homeoviscous adaptation to low temperatures in Staphylococcus aureus utilizing exogenous straight-chain unsaturated fatty acids. J Bacteriol 2024; 206:e0018724. [PMID: 38953643 PMCID: PMC11270863 DOI: 10.1128/jb.00187-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Accepted: 06/09/2024] [Indexed: 07/04/2024] Open
Abstract
It is well established that Staphylococcus aureus can incorporate exogenous straight-chain unsaturated fatty acids (SCUFAs) into membrane phospho- and glyco-lipids from various sources in supplemented culture media and when growing in vivo during infection. Given the enhancement of membrane fluidity when oleic acid (C18:1Δ9) is incorporated into lipids, we were prompted to examine the effect of medium supplementation with C18:1Δ9 on growth at low temperatures. C18:1Δ9 supported the growth of a cold-sensitive, branched-chain fatty acid (BCFA)-deficient mutant at 12°C. Interestingly, we found similar results in the BCFA-sufficient parental strain, supported by the fact that the incorporation of C18:1Δ9 into the membrane increased membrane fluidity in both strains. We show that the incorporation of C18:1Δ9 and its elongation product C20:1Δ11 into membrane lipids was required for growth stimulation and relied on a functional FakAB incorporation system. Lipidomics analysis of the phosphatidylglycerol and diglycosyldiacylglycerol lipid classes revealed major impacts of C18:1Δ9 and temperature on lipid species. Growth at 12°C in the presence of C18:1Δ9 also led to increased production of the carotenoid pigment staphyloxanthin. The enhancement of growth by C18:1Δ9 is an example of homeoviscous adaptation to low temperatures utilizing an exogenous fatty acid. This may be significant in the growth of S. aureus at low temperatures in foods that commonly contain C18:1Δ9 and other SCUFAs in various forms. IMPORTANCE We show that Staphylococcus aureus can use its known ability to incorporate exogenous fatty acids to enhance its growth at low temperatures. Individual species of phosphatidylglycerols and diglycosyldiacylglycerols bearing one or two degrees of unsaturation derived from the incorporation of C18:1Δ9 at 12°C are described for the first time. In addition, enhanced production of the carotenoid staphyloxanthin occurs at low temperatures. The studies describe a biochemical reality underlying membrane biophysics. This is an example of homeoviscous adaptation to low temperatures utilizing exogenous fatty acids over the regulation of the biosynthesis of endogenous fatty acids. The studies have likely relevance to food safety in that unsaturated fatty acids may enhance the growth of S. aureus in the food environment.
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Affiliation(s)
- Shannon C. Barbarek
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Ritika Shah
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Sharanya Paul
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Gloria Alvarado
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Keerthi Appala
- Department of Chemistry, University of Georgia, Athens, Georgia, USA
| | - Caiden Phillips
- Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A. T. Still University of Health Sciences, Kirksville, Missouri, USA
| | - Emma C. Henderson
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Evan T. Strandquist
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Antje Pokorny
- Department of Chemistry and Biochemistry, University of North Carolina-Wilmington, Wilmington, North Carolina, USA
| | - Vineet K. Singh
- Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A. T. Still University of Health Sciences, Kirksville, Missouri, USA
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Jan-Ulrik Dahl
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Kelly M. Hines
- Department of Chemistry, University of Georgia, Athens, Georgia, USA
| | - Brian J. Wilkinson
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
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4
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Freeman CD, Hansen T, Urbauer R, Wilkinson BJ, Singh VK, Hines KM. Defective pgsA contributes to increased membrane fluidity and cell wall thickening in Staphylococcus aureus with high-level daptomycin resistance. mSphere 2024; 9:e0011524. [PMID: 38752757 PMCID: PMC11332330 DOI: 10.1128/msphere.00115-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/17/2024] [Indexed: 05/28/2024] Open
Abstract
Daptomycin is a membrane-targeting last-resort antimicrobial therapeutic for the treatment of infections caused by methicillin- and/or vancomycin-resistant Staphylococcus aureus. In the rare event of failed daptomycin therapy, the source of resistance is often attributable to mutations directly within the membrane phospholipid biosynthetic pathway of S. aureus or in the regulatory systems that control cell envelope response and membrane homeostasis. Here we describe the structural changes to the cell envelope in a daptomycin-resistant isolate of S. aureus strain N315 that has acquired mutations in the genes most commonly reported associated with daptomycin resistance: mprF, yycG, and pgsA. In addition to the decreased phosphatidylglycerol (PG) levels that are the hallmark of daptomycin resistance, the mutant with high-level daptomycin resistance had increased branched-chain fatty acids (BCFAs) in its membrane lipids, increased membrane fluidity, and increased cell wall thickness. However, the successful utilization of isotope-labeled straight-chain fatty acids (SCFAs) in lipid synthesis suggested that the aberrant BCFA:SCFA ratio arose from upstream alteration in fatty acid synthesis rather than a structural preference in PgsA. Transcriptomics studies revealed that expression of pyruvate dehydrogenase (pdhB) was suppressed in the daptomycin-resistant isolate, which is known to increase BCFA levels. While complementation with an additional copy of pdhB had no effect, complementation of the pgsA mutation resulted in increased PG formation, reduction in cell wall thickness, restoration of normal BCFA levels, and increased daptomycin susceptibility. Collectively, these results demonstrate that pgsA contributes to daptomycin resistance through its influence on membrane fluidity and cell wall thickness, in addition to phosphatidylglycerol levels. IMPORTANCE The cationic lipopeptide antimicrobial daptomycin has become an essential tool for combating infections with Staphylococcus aureus that display reduced susceptibility to β-lactams or vancomycin. Since daptomycin's activity is based on interaction with the negatively charged membrane of S. aureus, routes to daptomycin-resistance occur through mutations in the lipid biosynthetic pathway surrounding phosphatidylglycerols and the regulatory systems that control cell envelope homeostasis. Therefore, there are many avenues to achieve daptomycin resistance and several different, and sometimes contradictory, phenotypes of daptomycin-resistant S. aureus, including both increased and decreased cell wall thickness and membrane fluidity. This study is significant because it demonstrates the unexpected influence of a lipid biosynthesis gene, pgsA, on membrane fluidity and cell wall thickness in S. aureus with high-level daptomycin resistance.
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Affiliation(s)
| | - Tayte Hansen
- Department of Microbiology and Immunology, A.T. Still University of Health Sciences, Kirksville, Missouri, USA
| | - Ramona Urbauer
- Department of Chemistry, University of Georgia, Athens, Georgia, USA
| | - Brian J. Wilkinson
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Vineet K. Singh
- Department of Microbiology and Immunology, A.T. Still University of Health Sciences, Kirksville, Missouri, USA
| | - Kelly M. Hines
- Department of Chemistry, University of Georgia, Athens, Georgia, USA
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5
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Marinho Righetto G, Alves Santos-Filho N, Oliveira Catarin Nunes L, André C, Souza JM, Andricopulo AD, Martins Bispo PJ, Cilli EM, Camargo ILBDC. Optimizing Bothropstoxin-I-Derived Peptides: Exploring the Antibacterial Potential of p-BthW. ACS OMEGA 2024; 9:23662-23674. [PMID: 38854567 PMCID: PMC11154919 DOI: 10.1021/acsomega.4c01303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 05/06/2024] [Accepted: 05/15/2024] [Indexed: 06/11/2024]
Abstract
Antimicrobial peptides are an emerging class of antibiotics that present a series of advantageous characteristics such as wide structural variety, broad spectrum of activity, and low propensity to select for resistance. They are found in all classes of life as defense molecules. A group of peptides derived from the protein Bothropstoxin-I has been previously studied as an alternative treatment against multi-drug-resistant bacteria. The peptide p-BthTX-I (sequence: KKYRYHLKPFCKK) and its homodimer, linked by disulfide oxidation through the residues of Cys11 and the serum degradation product [sequence: (KKYRYHLKPFC)2], were evaluated and showed similar antimicrobial activity. In this study, we synthesized an analogue of p-BthTX-I that uses the strategy of Fmoc-Lys(Fmoc)-OH in the C-terminal region for dimerization and tryptophan for all aromatic amino acids to provide better membrane interactions. This analogue, named p-BthW, displayed potent antibacterial activity at lower concentrations and maintained the same hemolytic levels as the original molecule. Our assessment revealed that p-BthW has a quick in vitro bactericidal action and prolonged post-antibiotic effect, comparable to the action of polymyxin B. The mode of action of p-BthW seems to rely not only on membrane depolarization but also on necrosis-like effects, especially in Gram-negative bacteria. Overall, the remarkable results regarding the propensity to develop resistance reaffirmed the great potential of the developed molecule.
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Affiliation(s)
- Gabriela Marinho Righetto
- Laboratory
of Molecular Epidemiology and Microbiology, Department of Physics
and Interdisciplinary Science, University
of Sao Paulo, 13563-120 São Carlos, Brazil
| | - Norival Alves Santos-Filho
- Department
of Biochemistry and Organic Chemistry, Institute of Chemistry, São Paulo State University, 14800-060 Araraquara, Brazil
| | - Letícia Oliveira Catarin Nunes
- Department
of Biochemistry and Organic Chemistry, Institute of Chemistry, São Paulo State University, 14800-060 Araraquara, Brazil
| | - Camille André
- Infectious
Disease Institute, Department of Ophthalmology, Massachusetts Eye
and Ear, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Julia Medeiros Souza
- Laboratory
of Medicinal and Computational Chemistry, Department of Physics and
Interdisciplinary Science, University of
Sao Paulo, 13563-120 São Carlos, Brazil
| | - Adriano Defini Andricopulo
- Laboratory
of Medicinal and Computational Chemistry, Department of Physics and
Interdisciplinary Science, University of
Sao Paulo, 13563-120 São Carlos, Brazil
| | - Paulo José Martins Bispo
- Infectious
Disease Institute, Department of Ophthalmology, Massachusetts Eye
and Ear, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Eduardo Maffud Cilli
- Department
of Biochemistry and Organic Chemistry, Institute of Chemistry, São Paulo State University, 14800-060 Araraquara, Brazil
| | - Ilana Lopes Baratella da Cunha Camargo
- Laboratory
of Molecular Epidemiology and Microbiology, Department of Physics
and Interdisciplinary Science, University
of Sao Paulo, 13563-120 São Carlos, Brazil
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6
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dos Santos Ferreira MC, Pendleton A, Yeo W, Málaga Gadea FC, Camelo D, McGuire M, Brinsmade SR. In Staphylococcus aureus, the acyl-CoA synthetase MbcS supports branched-chain fatty acid synthesis from carboxylic acid and aldehyde precursors. Mol Microbiol 2024; 121:865-881. [PMID: 38366323 PMCID: PMC11167679 DOI: 10.1111/mmi.15237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/16/2024] [Accepted: 01/22/2024] [Indexed: 02/18/2024]
Abstract
In the human pathogen Staphylococcus aureus, branched-chain fatty acids (BCFAs) are the most abundant fatty acids in membrane phospholipids. Strains deficient for BCFAs synthesis experience auxotrophy in laboratory culture and attenuated virulence during infection. Furthermore, the membrane of S. aureus is among the main targets for antibiotic therapy. Therefore, determining the mechanisms involved in BCFAs synthesis is critical to manage S. aureus infections. Here, we report that the overexpression of SAUSA300_2542 (annotated to encode an acyl-CoA synthetase) restores BCFAs synthesis in strains lacking the canonical biosynthetic pathway catalyzed by the branched-chain α-keto acid dehydrogenase (BKDH) complex. We demonstrate that the acyl-CoA synthetase activity of MbcS activates branched-chain carboxylic acids (BCCAs), and is required by S. aureus to utilize the isoleucine derivative 2-methylbutyraldehyde to restore BCFAs synthesis in S. aureus. Based on the ability of some staphylococci to convert branched-chain aldehydes into their respective BCCAs and our findings demonstrating that branched-chain aldehydes are in fact BCFAs precursors, we propose that MbcS promotes the scavenging of exogenous BCCAs and mediates BCFA synthesis via a de novo alternative pathway.
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Affiliation(s)
| | - Augustus Pendleton
- Department of BiologyGeorgetown UniversityWashingtonDistrict of ColumbiaUSA
- Present address:
Department of MicrobiologyCornell UniversityIthacaNew YorkUSA
| | - Won‐Sik Yeo
- Department of BiologyGeorgetown UniversityWashingtonDistrict of ColumbiaUSA
| | | | - Danna Camelo
- Department of BiologyGeorgetown UniversityWashingtonDistrict of ColumbiaUSA
| | - Maeve McGuire
- Department of BiologyGeorgetown UniversityWashingtonDistrict of ColumbiaUSA
| | - Shaun R. Brinsmade
- Department of BiologyGeorgetown UniversityWashingtonDistrict of ColumbiaUSA
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7
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Stubb H, Viitaja T, Trevorah RM, Raitanen JE, Moilanen J, Svedström KJ, Ekholm FS. Another Brick in the Wall of Tear Film Insights Added Through the Total Synthesis and Biophysical Profiling of anteiso-Branched Wax and Cholesteryl Esters. JOURNAL OF NATURAL PRODUCTS 2024; 87:954-965. [PMID: 38547477 PMCID: PMC11389978 DOI: 10.1021/acs.jnatprod.3c01247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
The tear film lipid layer (TFLL) plays a vital part in maintenance of ocular health and represents a unique biological barrier comprising unusual and specialized lipid classes and species. The wax and cholesteryl esters (WEs and CEs) constitute roughly 80-90% of the TFLL. The majority of species in these lipid classes are branched and it is therefore surprising that the synthesis and properties of the second largest category of species, i.e., the anteiso-branched species, remain poorly characterized. In this study, we have developed a total synthesis route and completed a detailed NMR spectroscopic characterization of two common anteiso-branched species, namely: (22S)-22-methyltetracosanyl oleate and cholesteryl (22'S)-22'-methyltetracosanoate. In addition, we have studied their structural properties in the bulk state by wide-angle and small-angle X-ray scattering and their behavior at the aqueous interface using Langmuir monolayer techniques. A comparison to the properties displayed by iso-branched and straight-chain analogues indicate that branching patterns lead to distinct properties in the CE and WE lipid classes. Overall, this study complements the previous work in the field and adds another important brick in the tear film insights wall.
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Affiliation(s)
- Henrik Stubb
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Tuomo Viitaja
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
- Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, FI-00290 Helsinki, Finland
| | - Ryan M Trevorah
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Jan-Erik Raitanen
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Jukka Moilanen
- Ophthalmology, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 8, FI-00290 Helsinki, Finland
| | - Kirsi J Svedström
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Filip S Ekholm
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
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8
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Lee TH, Charchar P, Separovic F, Reid GE, Yarovsky I, Aguilar MI. The intricate link between membrane lipid structure and composition and membrane structural properties in bacterial membranes. Chem Sci 2024; 15:3408-3427. [PMID: 38455013 PMCID: PMC10915831 DOI: 10.1039/d3sc04523d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 01/26/2024] [Indexed: 03/09/2024] Open
Abstract
It is now evident that the cell manipulates lipid composition to regulate different processes such as membrane protein insertion, assembly and function. Moreover, changes in membrane structure and properties, lipid homeostasis during growth and differentiation with associated changes in cell size and shape, and responses to external stress have been related to drug resistance across mammalian species and a range of microorganisms. While it is well known that the biomembrane is a fluid self-assembled nanostructure, the link between the lipid components and the structural properties of the lipid bilayer are not well understood. This perspective aims to address this topic with a view to a more detailed understanding of the factors that regulate bilayer structure and flexibility. We describe a selection of recent studies that address the dynamic nature of bacterial lipid diversity and membrane properties in response to stress conditions. This emerging area has important implications for a broad range of cellular processes and may open new avenues of drug design for selective cell targeting.
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Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University Clayton VIC 3800 Australia
| | - Patrick Charchar
- School of Engineering, RMIT University Melbourne Victoria 3001 Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne VIC 3010 Australia
| | - Gavin E Reid
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne VIC 3010 Australia
- Department of Biochemistry and Pharmacology, University of Melbourne Parkville VIC 3010 Australia
| | - Irene Yarovsky
- School of Engineering, RMIT University Melbourne Victoria 3001 Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University Clayton VIC 3800 Australia
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9
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Barbarek SC, Shah R, Paul S, Alvarado G, Appala K, Henderson EC, Strandquist ET, Pokorny A, Singh VK, Gatto C, Dahl JU, Hines KM, Wilkinson BJ. Lipidomics of homeoviscous adaptation to low temperatures in Staphylococcus aureus utilizing exogenous straight-chain unsaturated fatty acids over biosynthesized endogenous branched-chain fatty acids. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.02.578686. [PMID: 38352554 PMCID: PMC10862916 DOI: 10.1101/2024.02.02.578686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
It is well established that Staphylococcus aureus can incorporate exogenous straight-chain unsaturated fatty acids (SCUFAs) into membrane phospho- and glyco-lipids from various sources in supplemented culture media, and when growing in vivo in an infection. Given the enhancement of membrane fluidity when oleic acid (C18:1Δ9) is incorporated into lipids, we were prompted to examine the effect of medium supplementation with C18:1Δ9 on growth at low temperatures. C18:1Δ9 supported the growth of a cold-sensitive, branched-chain fatty acid (BCFA)-deficient mutant at 12°C. Interestingly, we found similar results in the BCFA-sufficient parental strain. We show that incorporation of C18:1Δ9 and its elongation product C20:1Δ9 into membrane lipids was required for growth stimulation and relied on a functional FakAB incorporation system. Lipidomics analysis of the phosphatidylglycerol (PG) and diglycosyldiacylglycerol (DGDG) lipid classes revealed major impacts of C18:1Δ9 and temperature on lipid species. Growth at 12°C in the presence of C18:1Δ9 also led to increased production of the carotenoid pigment staphyloxanthin; however, this was not an obligatory requirement for cold adaptation. Enhancement of growth by C18:1Δ9 is an example of homeoviscous adaptation to low temperatures utilizing an exogenous fatty acid. This may be significant in the growth of S. aureus at low temperatures in foods that commonly contain C18:1Δ9 and other SCUFAs in various forms.
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Affiliation(s)
| | - Ritika Shah
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Sharanya Paul
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Gloria Alvarado
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Keerthi Appala
- Department of Chemistry, University of Georgia, Athens, GA
| | - Emma C. Henderson
- School of Biological Sciences, Illinois State University, Normal, IL
| | | | - Antje Pokorny
- Department of Chemistry and Biochemistry, University of North Carolina-Wilmington, Wilmington, NC
| | - Vineet K. Singh
- Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A. T. Still University of Health Sciences, Kirksville, MO
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Jan-Ulrik Dahl
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Kelly M. Hines
- Department of Chemistry, University of Georgia, Athens, GA
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10
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Paudel S, Guedry S, Obernuefemann CLP, Hultgren SJ, Walker JN, Kulkarni R. Defining the Roles of Pyruvate Oxidation, TCA Cycle, and Mannitol Metabolism in Methicillin-Resistant Staphylococcus aureus Catheter-Associated Urinary Tract Infection. Microbiol Spectr 2023; 11:e0536522. [PMID: 37378538 PMCID: PMC10433999 DOI: 10.1128/spectrum.05365-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of complicated urinary tract infection (UTI) associated with the use of indwelling urinary catheters. Previous reports have revealed host and pathogen effectors critical for MRSA uropathogenesis. Here, we sought to determine the significance of specific metabolic pathways during MRSA UTI. First, we identified four mutants from the Nebraska transposon mutant library in the MRSA JE2 background that grew normally in rich medium but displayed significantly reduced growth in pooled human urine (HU). This prompted us to transduce the uropathogenic MRSA 1369 strain with the transposon mutants in sucD and fumC (tricarboxylic acid [TCA] cycle), mtlD (mannitol metabolism), and lpdA (pyruvate oxidation). Notably, sucD, fumC, and mtlD were also significantly upregulated in the MRSA 1369 strain upon exposure to HU. Compared to the WT, the MRSA 1369 lpdA mutant was significantly defective for (i) growth in HU, and (ii) colonization of the urinary tract and dissemination to the kidneys and the spleen in the mouse model of catheter-associated UTI (CAUTI), which may be attributed to its increased membrane hydrophobicity and higher susceptibility to killing by human blood. In contrast to their counterparts in the JE2 background, the sucD, fumC, and mtlD mutants in the MRSA 1369 background grew normally in HU; however, they displayed significant fitness defects in the CAUTI mouse model. Overall, identification of novel metabolic pathways important for the urinary fitness and survival of MRSA can be used for the development of novel therapeutics. IMPORTANCE While Staphylococcus aureus has historically not been considered a uropathogen, S. aureus urinary tract infection (UTI) is clinically significant in certain patient populations, including those with chronic indwelling urinary catheters. Moreover, most S. aureus strains causing catheter-associated UTI (CAUTI) are methicillin-resistant S. aureus (MRSA). MRSA is difficult to treat due to limited treatment options and the potential to deteriorate into life-threatening bacteremia, urosepsis, and shock. In this study, we found that pathways involved in pyruvate oxidation, TCA cycle, and mannitol metabolism are important for MRSA fitness and survival in the urinary tract. Improved understanding of the metabolic needs of MRSA in the urinary tract may help us develop novel inhibitors of MRSA metabolism that can be used to treat MRSA-CAUTI more effectively.
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Affiliation(s)
- Santosh Paudel
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - Sarah Guedry
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - Chloe L. P. Obernuefemann
- Center for Women’s Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Scott J. Hultgren
- Center for Women’s Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jennifer N. Walker
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA
- Department of Epidemiology, Human Genetics, and Environmental Science, School of Public Health, University of Texas Health Science Center at Houston, Texas, USA
| | - Ritwij Kulkarni
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
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11
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Liao X, Chen X, Sant'Ana AS, Feng J, Ding T. Pre-Exposure of Foodborne Staphylococcus aureus Isolates to Organic Acids Induces Cross-Adaptation to Mild Heat. Microbiol Spectr 2023; 11:e0383222. [PMID: 36916935 PMCID: PMC10101096 DOI: 10.1128/spectrum.03832-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 02/14/2023] [Indexed: 03/16/2023] Open
Abstract
Staphylococcus aureus is a typical enterotoxin-producing bacterium that causes food poisoning. In the food industry, pasteurization is the most widely used technique for food decontamination. However, pre-exposure to an acidic environment might make bacteria more resistant to heat treatment, which could compromise the bactericidal effect of heat treatment and endanger food safety. In this work, the organic acid-induced cross-adaptation of S. aureus isolates to heat and the associated mechanisms were investigated. Cross-adaptation area analysis indicated that pre-exposure to organic acids induced cross-adaptation of S. aureus to heat in a strain-dependent manner. Compared with other strains, S. aureus strain J15 showed extremely high heat resistance after being stressed by acetic acid, citric acid, and lactic acid. S. aureus strains J19, J9, and J17 were found to be unable to develop cross-adaptation to heat with pre-exposure to acetic acid, citric acid, and lactic acid, respectively. Analysis of the phenotypic characteristics of the cell membrane demonstrated that the acid-heat-cross-adapted strain J15 retained cell membrane integrity and functions through enhanced Na+K+-ATPase and FoF1-ATPase activities. Cell membrane fatty acid analysis revealed that the ratio of anteiso to iso branched-chain fatty acids in the acid-heat-cross-adapted strain J15 decreased and the content of straight-chain fatty acids exhibited a 2.9 to 4.4% increase, contributing to the reduction in membrane fluidity. At the molecular level, fabH was overexpressed with preconditioning by organic acid, and its expression was further enhanced with subsequent heat exposure. Organic acids activated the GroESL system, which participated in the heat shock response of S. aureus to the subsequent heat stress. IMPORTANCE Cross-adaptation is one of the most important phenotypes in foodborne pathogens and poses a potential risk to food safety and human health. In this work, we found that pretreatment with acetic acid, citric acid, and lactic acid could induce subsequent heat tolerance development in S. aureus. Various S. aureus strains exhibited different acid-heat cross-adaptation areas. The acid-induced cross-adaptation to heat might be attributable to membrane integrity maintenance, stabilization of the charge equilibrium to achieve a normal internal pH, and membrane fluidity reduction achieved by decreasing the ratios of anteiso to iso fatty acids. The fabH gene, which is involved in fatty acid biosynthesis, and groES/groEL, which are related to heat shock response, contributed to the development of the acid-heat cross-adaptation phenomenon in S. aureus. The investigations of the stress cross-adaptation phenomenon in foodborne pathogens could help optimize food processing to better control S. aureus.
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Affiliation(s)
- Xinyu Liao
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
- School of Mechanical and Energy Engineering, NingboTech University, Ningbo, China
- Future Food Laboratory, Innovation Center of Yangtze River Delta, Zhejiang University, Jiashan, China
| | - Xin Chen
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Anderson S. Sant'Ana
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil
| | - Jinsong Feng
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tian Ding
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
- Future Food Laboratory, Innovation Center of Yangtze River Delta, Zhejiang University, Jiashan, China
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12
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Whaley SG, Frank MW, Rock CO. A short-chain acyl-CoA synthetase that supports branched-chain fatty acid synthesis in Staphylococcus aureus. J Biol Chem 2023; 299:103036. [PMID: 36806679 PMCID: PMC10026030 DOI: 10.1016/j.jbc.2023.103036] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/24/2023] [Accepted: 02/09/2023] [Indexed: 02/18/2023] Open
Abstract
Staphylococcus aureus controls its membrane biophysical properties using branched-chain fatty acids (BCFAs). The branched-chain acyl-CoA precursors, utilized to initiate fatty acid synthesis, are derived from branched-chain ketoacid dehydrogenase (Bkd), a multiprotein complex that converts α-keto acids to their corresponding acyl-CoAs; however, Bkd KO strains still contain BCFAs. Here, we show that commonly used rich medias contain substantial concentrations of short-chain acids, like 2-methylbutyric and isobutyric acids, that are incorporated into membrane BCFAs. Bkd-deficient strains cannot grow in defined medium unless it is supplemented with either 2-methylbutyric or isobutyric acid. We performed a screen of candidate KO strains and identified the methylbutyryl-CoA synthetase (mbcS gene; SAUSA300_2542) as required for the incorporation of 2-methylbutyric and isobutyric acids into phosphatidylglycerol. Our mass tracing experiments show that isobutyric acid is converted to isobutyryl-CoA that flows into the even-chain acyl-acyl carrier protein intermediates in the type II fatty acid biosynthesis elongation cycle. Furthermore, purified MbcS is an ATP-dependent acyl-CoA synthetase that selectively catalyzes the activation of 2-methylbutyrate and isobutyrate. We found that butyrate and isovalerate are poor MbcS substrates and activity was not detected with acetate or short-chain dicarboxylic acids. Thus, MbcS functions to convert extracellular 2-methylbutyric and isobutyric acids to their respective acyl-CoAs that are used by 3-ketoacyl-ACP synthase III (FabH) to initiate BCFA biosynthesis.
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Affiliation(s)
- Sarah G Whaley
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Matthew W Frank
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Charles O Rock
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, Tennessee, USA.
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13
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Pendleton A, Yeo WS, Alqahtani S, DiMaggio DA, Stone CJ, Li Z, Singh VK, Montgomery CP, Bae T, Brinsmade SR. Regulation of the Sae Two-Component System by Branched-Chain Fatty Acids in Staphylococcus aureus. mBio 2022; 13:e0147222. [PMID: 36135382 PMCID: PMC9600363 DOI: 10.1128/mbio.01472-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/01/2022] [Indexed: 11/29/2022] Open
Abstract
Staphylococcus aureus is a ubiquitous Gram-positive bacterium and an opportunistic human pathogen. S. aureus pathogenesis relies on a complex network of regulatory factors that adjust gene expression. Two important factors in this network are CodY, a repressor protein responsive to nutrient availability, and the SaeRS two-component system (TCS), which responds to neutrophil-produced factors. Our previous work revealed that CodY regulates the secretion of many toxins indirectly via Sae through an unknown mechanism. We report that disruption of codY results in increased levels of phosphorylated SaeR (SaeR~P) and that codY mutant cell membranes contain a higher percentage of branched-chain fatty acids (BCFAs) than do wild-type membranes, prompting us to hypothesize that changes to membrane composition modulate the activity of the SaeS sensor kinase. Disrupting the lpdA gene encoding dihydrolipoyl dehydrogenase, which is critical for BCFA synthesis, significantly reduced the abundance of SaeR, phosphorylated SaeR, and BCFAs in the membrane, resulting in reduced toxin production and attenuated virulence. Lower SaeR levels could be explained in part by reduced stability. Sae activity in the lpdA mutant could be complemented genetically and chemically with exogenous short- or full-length BCFAs. Intriguingly, lack of lpdA also alters the activity of other TCSs, suggesting a specific BCFA requirement managing the basal activity of multiple TCSs. These results reveal a novel method of posttranscriptional virulence regulation via BCFA synthesis, potentially linking CodY activity to multiple virulence regulators in S. aureus. IMPORTANCE Two-component systems (TCSs) are an essential way that bacteria sense and respond to their environment. These systems are usually composed of a membrane-bound histidine kinase that phosphorylates a cytoplasmic response regulator. Because most of the histidine kinases are embedded in the membrane, lipids can allosterically regulate the activity of these sensors. In this study, we reveal that branched-chain fatty acids (BCFAs) are required for the activation of multiple TCSs in Staphylococcus aureus. Using both genetic and biochemical data, we show that the activity of the virulence activator SaeS and the phosphorylation of its response regulator SaeR are reduced in a branched-chain keto-acid dehydrogenase complex mutant and that defects in BCFA synthesis have far-reaching consequences for exotoxin secretion and virulence. Finally, we show that mutation of the global nutritional regulator CodY alters BCFA content in the membrane, revealing a potential mechanism of posttranscriptional regulation of the Sae system by CodY.
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Affiliation(s)
| | - Won-Sik Yeo
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Shahad Alqahtani
- Department of Biology, Georgetown University, Washington, DC, USA
| | | | - Carl J. Stone
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Zhaotao Li
- Center for Microbial Pathogenesis, Abigail Wexner Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA
| | - Vineet K. Singh
- Department of Microbiology and Immunology, A.T. Still University of Health Sciences, Kirksville, Missouri, USA
| | - Christopher P. Montgomery
- Center for Microbial Pathogenesis, Abigail Wexner Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA
- Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Taeok Bae
- Department of Microbiology and Immunology, Indiana University School of Medicine-Northwest, Gary, Indiana, USA
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14
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Romano GE, Silva-Pereira TT, de Melo FM, Sisco MC, Banari AC, Zimpel CK, Soler-Camargo NC, Guimarães AMDS. Unraveling the metabolism of Mycobacterium caprae using comparative genomics. Tuberculosis (Edinb) 2022; 136:102254. [PMID: 36126496 DOI: 10.1016/j.tube.2022.102254] [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: 02/27/2022] [Revised: 08/01/2022] [Accepted: 08/25/2022] [Indexed: 11/19/2022]
Abstract
In our laboratory, Mycobacterium caprae has poor growth in standard medium (SM) 7H9-OADC supplemented with pyruvate and Tween-80. Our objectives were to identify mutations affecting M. caprae metabolism and use this information to design a culture medium to improve its growth. We selected 77 M. caprae genomes and sequenced M. caprae NLA000201913 used in our experiments. Mutations present in >95% of the strains compared to Mycobacterium tuberculosis H37Rv were analyzed in silico for their deleterious effects on proteins of metabolic pathways. Apart from the known defect in the pyruvate kinase, M. caprae has important lesions in enzymes of the TCA cycle, methylmalonyl cycle, B12 metabolism, and electron-transport chain. We provide evidence of enzymatic redundancy elimination and epistatic mutations, and possible production of toxic metabolites hindering M. caprae growth in vitro. A newly designed SM supplemented with l-glutamate allowed faster growth and increased final microbial mass of M. caprae. However, possible accumulation of metabolic waste-products and/or nutritional limitations halted M. caprae growth prior to a M. tuberculosis-like stationary phase. Our findings suggest that M. caprae relies on GABA and/or glyoxylate shunts for in vitro growth in routine media. The newly developed medium will improve experiments with this bacterium by allowing faster growth in vitro.
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Affiliation(s)
- Giovanni Emiddio Romano
- Laboratory of Applied Research in Mycobacteria (LaPAM), Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, 1374 Prof Lineu Prestes Avenue, Room 229, São Paulo, SP, 05508-000, Brazil.
| | - Taiana Tainá Silva-Pereira
- Laboratory of Applied Research in Mycobacteria (LaPAM), Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, 1374 Prof Lineu Prestes Avenue, Room 229, São Paulo, SP, 05508-000, Brazil.
| | - Filipe Menegatti de Melo
- Laboratory of Applied Research in Mycobacteria (LaPAM), Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, 1374 Prof Lineu Prestes Avenue, Room 229, São Paulo, SP, 05508-000, Brazil.
| | - Maria Carolina Sisco
- Laboratory of Applied Research in Mycobacteria (LaPAM), Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, 1374 Prof Lineu Prestes Avenue, Room 229, São Paulo, SP, 05508-000, Brazil.
| | - Alexandre Campos Banari
- Laboratory of Applied Research in Mycobacteria (LaPAM), Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, 1374 Prof Lineu Prestes Avenue, Room 229, São Paulo, SP, 05508-000, Brazil; Department of Preventive Veterinary Medicine and Animal Health, College of Veterinary Medicine, University of São Paulo, 87 Prof Dr Orlando Marques de Paiva Avenue, São Paulo, SP, 05508-270, Brazil.
| | - Cristina Kraemer Zimpel
- Laboratory of Applied Research in Mycobacteria (LaPAM), Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, 1374 Prof Lineu Prestes Avenue, Room 229, São Paulo, SP, 05508-000, Brazil; Department of Preventive Veterinary Medicine and Animal Health, College of Veterinary Medicine, University of São Paulo, 87 Prof Dr Orlando Marques de Paiva Avenue, São Paulo, SP, 05508-270, Brazil.
| | - Naila Cristina Soler-Camargo
- Laboratory of Applied Research in Mycobacteria (LaPAM), Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, 1374 Prof Lineu Prestes Avenue, Room 229, São Paulo, SP, 05508-000, Brazil; Department of Preventive Veterinary Medicine and Animal Health, College of Veterinary Medicine, University of São Paulo, 87 Prof Dr Orlando Marques de Paiva Avenue, São Paulo, SP, 05508-270, Brazil.
| | - Ana Marcia de Sá Guimarães
- Laboratory of Applied Research in Mycobacteria (LaPAM), Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, 1374 Prof Lineu Prestes Avenue, Room 229, São Paulo, SP, 05508-000, Brazil; Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University. 625 Harrison Street, West Lafayette, IN, 47907, USA.
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15
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de Carvalho CCCR. Adaptation of Bacteria to Antineoplastic Agents Involves Persister Cells and Increases Resistance to Antibiotics. Bioengineering (Basel) 2022; 9:bioengineering9080355. [PMID: 36004880 PMCID: PMC9404991 DOI: 10.3390/bioengineering9080355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 07/25/2022] [Accepted: 07/27/2022] [Indexed: 11/16/2022] Open
Abstract
The increasing number of life-threatening infections observed in cancer patients has been ascribed to chemotherapy-induced neutropenia and to invasive medical procedures such as surgery and the application of catheters. In this study, it was questioned if the infections could also be favored by an increased resistance of bacteria due to the adaptation to antineoplastic agents used in chemotherapy. After exposure to several antineoplastic agents, it was observed that cells of Staphylococcus aureus, Mycobacterium vaccae, Pseudomonas aeruginosa, and Escherichia coli changed the fatty acid profile of their cellular membranes, produced exopolymeric substances, and formed aggregates that adhered to surfaces. Additionally, when exposed to high concentrations of these compounds, a persister sub-population could be identified. After adaptation to antineoplastic agents, the minimum inhibitory concentration (MIC) of several antibiotics increased considerably in the tested strains.
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Affiliation(s)
- Carla C. C. R. de Carvalho
- iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal; ; Tel.: +351-21-841-9594
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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16
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Flegler A, Iswara J, Mänz AT, Schocke FS, Faßbender WA, Hölzl G, Lipski A. Exogenous fatty acids affect membrane properties and cold adaptation of Listeria monocytogenes. Sci Rep 2022; 12:1499. [PMID: 35087150 PMCID: PMC8795206 DOI: 10.1038/s41598-022-05548-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/11/2022] [Indexed: 12/17/2022] Open
Abstract
Listeria monocytogenes is a food-borne pathogen that can grow at very low temperatures close to the freezing point of food and other matrices. Maintaining cytoplasmic membrane fluidity by changing its lipid composition is indispensable for growth at low temperatures. Its dominant adaptation is to shorten the fatty acid chain length and, in some strains, increase in addition the menaquinone content. To date, incorporation of exogenous fatty acid was not reported for Listeria monocytogenes. In this study, the membrane fluidity grown under low-temperature conditions was affected by exogenous fatty acids incorporated into the membrane phospholipids of the bacterium. Listeria monocytogenes incorporated exogenous fatty acids due to their availability irrespective of their melting points. Incorporation was demonstrated by supplementation of the growth medium with polysorbate 60, polysorbate 80, and food lipid extracts, resulting in a corresponding modification of the membrane fatty acid profile. Incorporated exogenous fatty acids had a clear impact on the fitness of the Listeria monocytogenes strains, which was demonstrated by analyses of the membrane fluidity, resistance to freeze-thaw stress, and growth rates. The fatty acid content of the growth medium or the food matrix affects the membrane fluidity and thus proliferation and persistence of Listeria monocytogenes in food under low-temperature conditions.
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Affiliation(s)
- Alexander Flegler
- Department of Food Microbiology and Hygiene, Institute of Nutritional and Food Science (IEL), University of Bonn, 53115, Bonn, Germany
| | - Janice Iswara
- Department of Food Microbiology and Hygiene, Institute of Nutritional and Food Science (IEL), University of Bonn, 53115, Bonn, Germany
| | - Anna Tatjana Mänz
- Department of Food Microbiology and Hygiene, Institute of Nutritional and Food Science (IEL), University of Bonn, 53115, Bonn, Germany
| | - Frieda Sophia Schocke
- Department of Food Microbiology and Hygiene, Institute of Nutritional and Food Science (IEL), University of Bonn, 53115, Bonn, Germany
| | - Wanda Antonia Faßbender
- Department of Food Microbiology and Hygiene, Institute of Nutritional and Food Science (IEL), University of Bonn, 53115, Bonn, Germany
| | - Georg Hölzl
- Department of Molecular Biotechnology, Institute of Molecular Physiology and Biotechnology of Plants (IMBIO), University of Bonn, 53115, Bonn, Germany
| | - André Lipski
- Department of Food Microbiology and Hygiene, Institute of Nutritional and Food Science (IEL), University of Bonn, 53115, Bonn, Germany.
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17
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Wongthong S, Taron W, Chanawong A, Tippayawat P, Pongdontri P, Srisrattakarn A, Panpru P, Lulitanond A. Effect of Vancomycin on Cellular Fatty Acid Profiles of Vancomycin-Susceptible and Nonsusceptible Staphylococcus aureus. Microb Drug Resist 2021; 28:267-273. [PMID: 34748415 DOI: 10.1089/mdr.2021.0055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Vancomycin is widely used for treatment of infection caused by methicillin-resistant Staphylococcus aureus (MRSA) leading to an increasing appearance of low-level vancomycin-resistant isolates called heterogeneous vancomycin-intermediate S. aureus (hVISA). The mechanism of vancomycin tolerance in hVISA is still unclear. This study aimed to investigate the fatty acid compositions of S. aureus isolates under the stress environment with vancomycin. The different responses of hVISA and vancomycin-susceptible S. aureus (VSSA) may lead to more understanding the mechanism. The bacterial lipid profiles were tested three times from three extractions of each isolate cultured on tryptic soy agar (TSA) and TSA with vancomycin. Of the 30 MRSA isolates studied, 13, 12, and 5 isolates were VSSA, hVISA, and VISA, respectively. The analysis of bacterial lipid profiles showed that under vancomycin stress, there was a reduction of straight chain fatty acids (SCFAs) in VSSA isolates but an increase in branched chain fatty acids (BCFAs). In contrast, the hVISA group exhibited an increase only in the BCFAs but not in SCFAs. Of interest, vancomycin had no effect on either BCFAs or SCFAs of the VISA cells. This study provided information of bacterial adaptation during stress with vancomycin that may be helpful to overcome the resistant bacteria.
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Affiliation(s)
- Sujintana Wongthong
- Department of Clinical Microbiology and Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.,Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.,Faculty of Medical Technology, Nakhon Ratchasima College, Nakhon Ratchasima, Thailand
| | - Wichit Taron
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Aroonwadee Chanawong
- Department of Clinical Microbiology and Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.,Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Patcharaporn Tippayawat
- Department of Clinical Microbiology and Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.,Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Paweena Pongdontri
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Arpasiri Srisrattakarn
- Department of Clinical Microbiology and Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.,Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Pimchanok Panpru
- Department of Clinical Microbiology and Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.,Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Aroonlug Lulitanond
- Department of Clinical Microbiology and Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.,Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
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18
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Frank MW, Whaley SG, Rock CO. Branched-chain amino acid metabolism controls membrane phospholipid structure in Staphylococcus aureus. J Biol Chem 2021; 297:101255. [PMID: 34592315 PMCID: PMC8524195 DOI: 10.1016/j.jbc.2021.101255] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/12/2021] [Accepted: 09/14/2021] [Indexed: 11/30/2022] Open
Abstract
Branched-chain amino acids (primarily isoleucine) are important regulators of virulence and are converted to precursor molecules used to initiate fatty acid synthesis in Staphylococcus aureus. Defining how bacteria control their membrane phospholipid composition is key to understanding their adaptation to different environments. Here, we used mass tracing experiments to show that extracellular isoleucine is preferentially metabolized by the branched-chain ketoacid dehydrogenase complex, in contrast to valine, which is not efficiently converted to isobutyryl-CoA. This selectivity creates a ratio of anteiso:iso C5-CoAs that matches the anteiso:iso ratio in membrane phospholipids, indicating indiscriminate utilization of these precursors by the initiation condensing enzyme FabH. Lipidomics analysis showed that removal of isoleucine and leucine from the medium led to the replacement of phospholipid molecular species containing anteiso/iso 17- and 19-carbon fatty acids with 18- and 20-carbon straight-chain fatty acids. This compositional change is driven by an increase in the acetyl-CoA:C5-CoA ratio, enhancing the utilization of acetyl-CoA by FabH. The acyl carrier protein (ACP) pool normally consists of odd carbon acyl-ACP intermediates, but when branched-chain amino acids are absent from the environment, there was a large increase in even carbon acyl-ACP pathway intermediates. The high substrate selectivity of PlsC ensures that, in the presence or the absence of extracellular Ile/Leu, the 2-position is occupied by a branched-chain 15-carbon fatty acid. These metabolomic measurements show how the metabolism of isoleucine and leucine, rather than the selectivity of FabH, control the structure of membrane phospholipids.
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Affiliation(s)
- Matthew W Frank
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Sarah G Whaley
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Charles O Rock
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, Tennessee, USA.
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19
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Baggio G, Groves RA, Chignola R, Piacenza E, Presentato A, Lewis IA, Lampis S, Vallini G, Turner RJ. Untargeted Metabolomics Investigation on Selenite Reduction to Elemental Selenium by Bacillus mycoides SeITE01. Front Microbiol 2021; 12:711000. [PMID: 34603239 PMCID: PMC8481872 DOI: 10.3389/fmicb.2021.711000] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 08/16/2021] [Indexed: 12/02/2022] Open
Abstract
Bacillus mycoides SeITE01 is an environmental isolate that transforms the oxyanion selenite (SeO 3 2 - ) into the less bioavailable elemental selenium (Se0) forming biogenic selenium nanoparticles (Bio-SeNPs). In the present study, the reduction of sodium selenite (Na2SeO3) by SeITE01 strain and the effect ofSeO 3 2 - exposure on the bacterial cells was examined through untargeted metabolomics. A time-course approach was used to monitor both cell pellet and cell free spent medium (referred as intracellular and extracellular, respectively) metabolites in SeITE01 cells treated or not withSeO 3 2 - . The results show substantial biochemical changes in SeITE01 cells when exposed toSeO 3 2 - . The initial uptake ofSeO 3 2 - by SeITE01 cells (3h after inoculation) shows both an increase in intracellular levels of 4-hydroxybenzoate and indole-3-acetic acid, and an extracellular accumulation of guanosine, which are metabolites involved in general stress response adapting strategies. Proactive and defensive mechanisms againstSeO 3 2 - are observed between the end of lag (12h) and beginning of exponential (18h) phases. Glutathione and N-acetyl-L-cysteine are thiol compounds that would be mainly involved in Painter-type reaction for the reduction and detoxification ofSeO 3 2 - to Se0. In these growth stages, thiol metabolites perform a dual role, both acting against the toxic and harmful presence of the oxyanion and as substrate or reducing sources to scavenge ROS production. Moreover, detection of the amino acids L-threonine and ornithine suggests changes in membrane lipids. Starting from stationary phase (24 and 48h), metabolites related to the formation and release of SeNPs in the extracellular environment begin to be observed. 5-hydroxyindole acetate, D-[+]-glucosamine, 4-methyl-2-oxo pentanoic acid, and ethanolamine phosphate may represent signaling strategies following SeNPs release from the cytoplasmic compartment, with consequent damage to SeITE01 cell membranes. This is also accompanied by intracellular accumulation of trans-4-hydroxyproline and L-proline, which likely represent osmoprotectant activity. The identification of these metabolites suggests the activation of signaling strategies that would protect the bacterial cells fromSeO 3 2 - toxicity while it is converting into SeNPs.
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Affiliation(s)
- Greta Baggio
- Department of Biotechnology, University of Verona, Verona, Italy
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Ryan A. Groves
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Roberto Chignola
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Elena Piacenza
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Palermo, Italy
| | - Alessandro Presentato
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Palermo, Italy
| | - Ian A. Lewis
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Silvia Lampis
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Giovanni Vallini
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Raymond J. Turner
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
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20
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Freeman C, Hynds HM, Carpenter JM, Appala K, Bimpeh K, Barbarek S, Gatto C, Wilkinson BJ, Hines KM. Revealing Fatty Acid Heterogeneity in Staphylococcal Lipids with Isotope Labeling and RPLC-IM-MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:2376-2385. [PMID: 34014662 DOI: 10.1021/jasms.1c00092] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Up to 80% of the fatty acids in Staphylococcus aureus membrane lipids are branched, rather than straight-chain, fatty acids. The branched fatty acids (BCFAs) may have either an even or odd number of carbons, and the branch position may be at the penultimate carbon (iso) or the antepenultimate (anteiso) carbon of the tail. This results in two sets of isomeric fatty acid species with the same number of carbons that cannot be resolved by mass spectrometry. The isomer/isobar challenge is further complicated when the mixture of BCFAs and straight-chain fatty acids (SCFAs) are esterified into diacylated lipids such as the phosphatidylglycerol (PG) species of the S. aureus membrane. No conventional chromatographic method has been able to resolve diacylated lipids containing mixtures of SCFAs, anteiso-odd, iso-odd, and iso-even BCFAs. A major hurdle to method development in this area is the lack of relevant analytical standards for lipids containing BCFA isomers. The diversity of the S. aureus lipidome and its naturally high levels of BCFAs present an opportunity to explore the potential of resolving diacylated lipids containing BCFAs and SFCAs. Using our knowledge of lipid and fatty acid biosynthesis in S. aureus, we have used a stable-isotope-labeling strategy to develop and validate a 30 min C18 reversed-phase liquid chromatography method combined with traveling-wave ion mobility-mass spectrometry to provide resolution of diacylated lipids based on the number of BCFAs that they contain.
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Affiliation(s)
- Christian Freeman
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Hannah M Hynds
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Jana M Carpenter
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Keerthi Appala
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Kingsley Bimpeh
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Shannon Barbarek
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790, United States
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790, United States
| | - Brian J Wilkinson
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790, United States
| | - Kelly M Hines
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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21
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Fluorescence Polarization (FP) Assay for Measuring Staphylococcus aureus Membrane Fluidity. Methods Mol Biol 2021; 2341:55-68. [PMID: 34264461 DOI: 10.1007/978-1-0716-1550-8_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Fluorescence polarization is a method to determine membrane fluidity using a hydrophobic fluorescent dye that intercalates into the fatty acid bilayer. A spectrofluorometer is used to polarize UV light as a vertical excitation beam which passes through the dye-labeled membrane where the dye fluoresces. The beams perpendicular and horizontal to the excitation light are then collected and analyzed. Membrane structural properties are largely due to the packing of the fatty acids in the lipid bilayer that determines the membrane biophysical parameters. Staphylococcus aureus contains straight-chain (SCFAs) and branched-chain (BCFAs) fatty acids in the membrane and alters the proportion of membrane fluidizing BCFAs and stabilizing SCFAs as a response to a variety of stresses. Herein, we describe a method for determination of membrane fluidity in S. aureus using diphenylhexatriene, one of the most used fluorescent dyes for this purpose.
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22
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Trautmann A, Schleicher L, Deusch S, Gätgens J, Steuber J, Seifert J. Short-Chain Fatty Acids Modulate Metabolic Pathways and Membrane Lipids in Prevotella bryantii B 14. Proteomes 2020; 8:28. [PMID: 33081314 PMCID: PMC7709123 DOI: 10.3390/proteomes8040028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/26/2022] Open
Abstract
Short-chain fatty acids (SCFAs) are bacterial products that are known to be used as energy sources in eukaryotic hosts, whereas their role in the metabolism of intestinal microbes is rarely explored. In the present study, acetic, propionic, butyric, isobutyric, valeric, and isovaleric acid, respectively, were added to a newly defined medium containing Prevotella bryantii B14 cells. After 8 h and 24 h, optical density, pH and SCFA concentrations were measured. Long-chain fatty acid (LCFA) profiles of the bacterial cells were analyzed via gas chromatography-time of flight-mass spectrometry (GC-ToF MS) and proteins were quantified using a mass spectrometry-based, label-free approach. Cultures supplemented with single SCFAs revealed different growth behavior. Structural features of the respective SCFAs were identified in the LCFA profiles, which suggests incorporation into the bacterial membranes. The proteomes of cultures supplemented with acetic and valeric acid differed by an increased abundance of outer membrane proteins. The proteome of the isovaleric acid supplementation showed an increase of proteins in the amino acid metabolism. Our findings indicate a possible interaction between SCFAs, the lipid membrane composition, the abundance of outer membrane proteins, and a modulation of branched chain amino acid biosynthesis by isovaleric acid.
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Affiliation(s)
- Andrej Trautmann
- Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany; (A.T.); (S.D.)
| | - Lena Schleicher
- Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany; (L.S.); (J.S.)
| | - Simon Deusch
- Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany; (A.T.); (S.D.)
| | - Jochem Gätgens
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany;
| | - Julia Steuber
- Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany; (L.S.); (J.S.)
| | - Jana Seifert
- Institute of Animal Science, University of Hohenheim, 70599 Stuttgart, Germany; (A.T.); (S.D.)
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23
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Khemici V, Prados J, Petrignani B, Di Nolfi B, Bergé E, Manzano C, Giraud C, Linder P. The DEAD-box RNA helicase CshA is required for fatty acid homeostasis in Staphylococcus aureus. PLoS Genet 2020; 16:e1008779. [PMID: 32730248 PMCID: PMC7392221 DOI: 10.1371/journal.pgen.1008779] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 04/15/2020] [Indexed: 01/05/2023] Open
Abstract
Staphylococcus aureus is an opportunistic pathogen that can grow in a wide array of conditions: on abiotic surfaces, on the skin, in the nose, in planktonic or biofilm forms and can cause many type of infections. Consequently, S. aureus must be able to adapt rapidly to these changing growth conditions, an ability largely driven at the posttranscriptional level. RNA helicases of the DEAD-box family play an important part in this process. In particular, CshA, which is part of the degradosome, is required for the rapid turnover of certain mRNAs and its deletion results in cold-sensitivity. To understand the molecular basis of this phenotype, we conducted a large genetic screen isolating 82 independent suppressors of cold growth. Full genome sequencing revealed the fatty acid synthesis pathway affected in many suppressor strains. Consistent with that result, sublethal doses of triclosan, a FASII inhibitor, can partially restore growth of a cshA mutant in the cold. Overexpression of the genes involved in branched-chain fatty acid synthesis was also able to suppress the cold-sensitivity. Using gas chromatography analysis of fatty acids, we observed an imbalance of straight and branched-chain fatty acids in the cshA mutant, compared to the wild-type. This imbalance is compensated in the suppressor strains. Thus, we reveal for the first time that the cold sensitive growth phenotype of a DEAD-box mutant can be explained, at least partially, by an improper membrane composition. The defect correlates with an accumulation of the pyruvate dehydrogenase complex mRNA, which is inefficiently degraded in absence of CshA. We propose that the resulting accumulation of acetyl-CoA fuels straight-chained fatty acid production at the expense of the branched ones. Strikingly, addition of acetate into the medium mimics the cshA deletion phenotype, resulting in cold sensitivity suppressed by the mutations found in our genetic screen or by sublethal doses of triclosan. DEAD-box RNA helicases are highly conserved proteins found in all domains of life. By acting on RNA secondary structures they determine the fate of RNA from transcription to degradation. Bacterial DEAD-box RNA helicases are not essential under laboratory conditions but are required for fitness and under stress conditions. Whereas many DEAD-box protein mutants display a cold sensitive phenotype, the underlying mechanisms have been studied only in few cases and found to be associated with ribosome biogenesis. We aimed here to elucidate the cold sensitivity of a cshA mutant in the Gram-positive opportunist pathogen Staphylococcus aureus. Our study revealed for the first time that part of the cold sensitivity is related to the inability of the bacterium to adapt the cytoplasmic membrane to lower temperatures. We propose that straight-chain fatty acid synthesis, reduced to sustain growth at lower temperature, is maintained due to inefficient turn-over of the pyruvate dehydrogenase mRNA, leading to elevated acetyl-CoA levels. This study allowed us to unravel at least in part the cold sensitive phenotype and to show that the pyruvate dehydrogenase activity plays an important function in the regulation of fatty acid composition of the membrane, a process that remains poorly understood in Gram-positive bacteria.
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Affiliation(s)
- Vanessa Khemici
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Julien Prados
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Bianca Petrignani
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Benjamin Di Nolfi
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Elodie Bergé
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Caroline Manzano
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Caroline Giraud
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Patrick Linder
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- * E-mail:
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24
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Exogenous Fatty Acids Remodel Staphylococcus aureus Lipid Composition through Fatty Acid Kinase. J Bacteriol 2020; 202:JB.00128-20. [PMID: 32366591 DOI: 10.1128/jb.00128-20] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/29/2020] [Indexed: 12/30/2022] Open
Abstract
Staphylococcus aureus can utilize exogenous fatty acids for phospholipid synthesis. The fatty acid kinase FakA is essential for this utilization by phosphorylating exogenous fatty acids for incorporation into lipids. How FakA impacts the lipid membrane composition is unknown. In this study, we used mass spectrometry to determine the membrane lipid composition and properties of S. aureus in the absence of fakA We found the fakA mutant to have increased abundance of lipids containing longer acyl chains. Since S. aureus does not synthesize unsaturated fatty acids, we utilized oleic acid (18:1) to track exogenous fatty acid incorporation into lipids. We observed a concentration-dependent incorporation of exogenous fatty acids into the membrane that required FakA. We also tested how FakA and exogenous fatty acids impact membrane-related physiology and identified changes in membrane potential, cellular respiration, and membrane fluidity. To mimic the host environment, we characterized the lipid composition of wild-type and fakA mutant bacteria grown in mouse skin homogenate. We show that wild-type S. aureus can incorporate exogenous unsaturated fatty acids from host tissue, highlighting the importance of FakA in the presence of host skin tissue. In conclusion, FakA is important for maintaining the composition and properties of the phospholipid membrane in the presence of exogenous fatty acids, impacting overall cell physiology.IMPORTANCE Environmental fatty acids can be harvested to supplement endogenous fatty acid synthesis to produce membranes and circumvent fatty acid biosynthesis inhibitors. However, how the inability to use these fatty acids impacts lipids is unclear. Our results reveal lipid composition changes in response to fatty acid addition and when S. aureus is unable to activate fatty acids through FakA. We identify concentration-dependent utilization of oleic acid that, when combined with previous work, provides evidence that fatty acids can serve as a signal to S. aureus Furthermore, using mouse skin homogenates as a surrogate for in vivo conditions, we showed that S. aureus can incorporate host fatty acids. This study highlights how exogenous fatty acids impact bacterial membrane composition and function.
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25
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Frank MW, Yao J, Batte JL, Gullett JM, Subramanian C, Rosch JW, Rock CO. Host Fatty Acid Utilization by Staphylococcus aureus at the Infection Site. mBio 2020; 11:e00920-20. [PMID: 32430471 PMCID: PMC7240157 DOI: 10.1128/mbio.00920-20] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 04/20/2020] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus utilizes the fatty acid (FA) kinase system to activate exogenous FAs for membrane synthesis. We developed a lipidomics workflow to determine the membrane phosphatidylglycerol (PG) molecular species synthesized by S. aureus at the thigh infection site. Wild-type S. aureus utilizes both host palmitate and oleate to acylate the 1 position of PG, and the 2 position is occupied by pentadecanoic acid arising from de novo biosynthesis. Inactivation of FakB2 eliminates the ability to assimilate oleate and inactivation of FakB1 reduces the content of saturated FAs and enhances oleate utilization. Elimination of FA activation in either ΔfakA or ΔfakB1 ΔfakB2 mutants does not impact growth. All S. aureus strains recovered from the thigh have significantly reduced branched-chain FAs and increased even-chain FAs compared to that with growth in rich laboratory medium. The molecular species pattern observed in the thigh was reproduced in the laboratory by growth in isoleucine-deficient medium containing exogenous FAs. S. aureus utilizes specific host FAs for membrane biosynthesis but also requires de novo FA biosynthesis initiated by isoleucine (or leucine) to produce pentadecanoic acid.IMPORTANCE The shortage of antibiotics against drug-resistant Staphylococcus aureus has led to the development of new drugs targeting the elongation cycle of fatty acid (FA) synthesis that are progressing toward the clinic. An objection to the use of FA synthesis inhibitors is that S. aureus can utilize exogenous FAs to construct its membrane, suggesting that the bacterium would bypass these therapeutics by utilizing host FAs instead. We developed a mass spectrometry workflow to determine the composition of the S. aureus membrane at the infection site to directly address how S. aureus uses host FAs. S. aureus strains that cannot acquire host FAs are as effective in establishing an infection as the wild type, but strains that require the utilization of host FAs for growth were attenuated in the mouse thigh infection model. We find that S. aureus does utilize host FAs to construct its membrane, but host FAs do not replace the requirement for pentadecanoic acid, a branched-chain FA derived from isoleucine (or leucine) that predominantly occupies the 2 position of S. aureus phospholipids. The membrane phospholipid structure of S. aureus mutants that cannot utilize host FAs indicates the isoleucine is a scarce resource at the infection site. This reliance on the de novo synthesis of predominantly pentadecanoic acid that cannot be obtained from the host is one reason why drugs that target fatty acid synthesis are effective in treating S. aureus infections.
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Affiliation(s)
- Matthew W Frank
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jiangwei Yao
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Justin L Batte
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jessica M Gullett
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Chitra Subramanian
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jason W Rosch
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Charles O Rock
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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26
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Tiwari KB, Gatto C, Wilkinson BJ. Plasticity of Coagulase-Negative Staphylococcal Membrane Fatty Acid Composition and Implications for Responses to Antimicrobial Agents. Antibiotics (Basel) 2020; 9:E214. [PMID: 32354049 PMCID: PMC7277709 DOI: 10.3390/antibiotics9050214] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 04/18/2020] [Accepted: 04/27/2020] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus demonstrates considerable membrane lipid plasticity in response to different growth environments, which is of potential relevance to response and resistance to various antimicrobial agents. This information is not available for various species of coagulase-negative staphylococci, which are common skin inhabitants, can be significant human pathogens, and are resistant to multiple antibiotics. We determined the total fatty acid compositions of Staphylococcus auricularis, Staphylococcus capitis, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus saprophyticus, and Staphylococcus aureus for comparison purposes. Different proportions of branched-chain and straight-chain fatty acids were observed amongst the different species. However, growth in cation-supplemented Mueller-Hinton broth significantly increased the proportion of branched-chain fatty acids, and membrane fluidities as measured by fluorescence anisotropy. Cation-supplemented Mueller-Hinton broth is used for routine determination of antimicrobial susceptibilities. Growth in serum led to significant increases in straight-chain unsaturated fatty acids in the total fatty acid profiles, and decreases in branched-chain fatty acids. This indicates preformed fatty acids can replace biosynthesized fatty acids in the glycerolipids of coagulase-negative staphylococci, and indicates that bacterial fatty acid biosynthesis system II may not be a good target for antimicrobial agents in these organisms. Even though the different species are expected to be exposed to skin antimicrobial fatty acids, they were susceptible to the major skin antimicrobial fatty acid sapienic acid (C16:1Δ6). Certain species were not susceptible to linoleic acid (C18:2Δ9,12), but no obvious relationship to fatty acid composition could be discerned.
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Affiliation(s)
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, IL 61761, USA
| | - Brian J. Wilkinson
- School of Biological Sciences, Illinois State University, Normal, IL 61761, USA
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27
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Bachochin MJ, Venegas JC, Singh G, Zhang L, Barber RD. Characterization of a butyrate kinase from Desulfovibrio vulgaris str. Hildenborough. FEMS Microbiol Lett 2020; 367:5804727. [PMID: 32166312 DOI: 10.1093/femsle/fnaa047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/10/2020] [Indexed: 11/13/2022] Open
Abstract
Short and branched chain fatty acid kinases participate in both bacterial anabolic and catabolic processes, including fermentation, through the reversible, ATP-dependent synthesis of acyl phosphates. This study reports biochemical properties of a predicted butyrate kinase from Desulfovibrio vulgaris str. Hildenborough (DvBuk) expressed heterologously and purified from Escherichia coli. Gel filtration chromatography indicates purified DvBuk is active as a dimer. The optimum temperature and pH for DvBuk activity is 44°C and 7.5, respectively. The enzyme displays enhanced thermal stability in the presence of substrates as observed for similar enzymes. Measurement of kcat and KM for various substrates reveals DvBuk exhibits the highest catalytic efficiencies for butyrate, valerate and isobutyrate. In particular, these measurements reveal this enzyme's apparent high affinity for C4 fatty acids relative to other butyrate kinases. These results have implications on structure and function relationships within the ASKHA superfamily of phosphotransferases, particularly regarding the acyl binding pocket, as well as potential physiological roles for this enzyme in Desulfovibrio vulgaris str. Hildenborough.
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Affiliation(s)
- Maxwell J Bachochin
- Department of Biological Sciences, College of Natural and Health Sciences, University of Wisconsin-Parkside, Room 355 Greenquist Hall; 900 Wood Rd., Kenosha, WI 53141-2000, USA
| | - Jessica Castillo Venegas
- Department of Biological Sciences, College of Natural and Health Sciences, University of Wisconsin-Parkside, Room 355 Greenquist Hall; 900 Wood Rd., Kenosha, WI 53141-2000, USA
| | - Gundeep Singh
- Department of Biological Sciences, College of Natural and Health Sciences, University of Wisconsin-Parkside, Room 355 Greenquist Hall; 900 Wood Rd., Kenosha, WI 53141-2000, USA
| | - Liyang Zhang
- Department of Biological Sciences, College of Natural and Health Sciences, University of Wisconsin-Parkside, Room 355 Greenquist Hall; 900 Wood Rd., Kenosha, WI 53141-2000, USA
| | - Robert D Barber
- Department of Biological Sciences, College of Natural and Health Sciences, University of Wisconsin-Parkside, Room 355 Greenquist Hall; 900 Wood Rd., Kenosha, WI 53141-2000, USA
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28
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Abstract
Bacterial metabolism represents the biochemical space that bacteria can manipulate to produce energy, reducing equivalents and building blocks for replication. Gram-positive pathogens, such as Listeria monocytogenes, show remarkable flexibility, which allows for exploitation of diverse biological niches from the soil to the intracytosolic space. Although the human host represents a potentially rich source for nutrient acquisition, competition for nutrients with the host and hostile host defenses can constrain bacterial metabolism by various mechanisms, including nutrient sequestration. Here, we review metabolism in the model Gram-positive bacterium, L. monocytogenes, and highlight pathways that enable the replication, survival, and virulence of this bacterial pathogen.
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29
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Chen X, Alonzo F. Bacterial lipolysis of immune-activating ligands promotes evasion of innate defenses. Proc Natl Acad Sci U S A 2019; 116:3764-3773. [PMID: 30755523 PMCID: PMC6397559 DOI: 10.1073/pnas.1817248116] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Commensal and pathogenic bacteria hydrolyze host lipid substrates with secreted lipases and phospholipases for nutrient acquisition, colonization, and infection. Bacterial lipase activity on mammalian lipids and phospholipids can promote release of free fatty acids from lipid stores, detoxify antimicrobial lipids, and facilitate membrane dissolution. The gram-positive bacterium Staphylococcus aureus secretes at least two lipases, Sal1 and glycerol ester hydrolase (Geh), with specificities for short- and long-chain fatty acids, respectively, each with roles in the hydrolysis of environmental lipids. In a recent study from our group, we made the unexpected observation that Geh released by S. aureus inhibits activation of innate immune cells. Herein, we investigated the possibility that S. aureus lipases interface with the host immune system to blunt innate immune recognition of the microbe. We found that the Geh lipase, but not other S. aureus lipases, prevents activation of innate cells in culture. Mutation of geh leads to enhancement of proinflammatory cytokine production during infection, increased innate immune activity, and improved clearance of the bacterium in infected tissue. These in vitro and in vivo effects on innate immunity were not due to direct functions of the lipase on mammalian cells, but rather a result of inactivation of S. aureus lipoproteins, a major pathogen-associated molecular pattern (PAMP) of extracellular gram-positive bacteria, via ester hydrolysis. Altogether, these studies provide insight into an adaptive trait that masks microbial recognition by innate immune cells through targeted inactivation of a broadly conserved PAMP.
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Affiliation(s)
- Xi Chen
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153
| | - Francis Alonzo
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153
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30
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Perez-Lopez MI, Mendez-Reina R, Trier S, Herrfurth C, Feussner I, Bernal A, Forero-Shelton M, Leidy C. Variations in carotenoid content and acyl chain composition in exponential, stationary and biofilm states of Staphylococcus aureus, and their influence on membrane biophysical properties. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:978-987. [PMID: 30771288 DOI: 10.1016/j.bbamem.2019.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/01/2019] [Accepted: 02/04/2019] [Indexed: 01/01/2023]
Abstract
Bacteria are often found in close association with surfaces, resulting in the formation of biofilms. In Staphylococcus aureus (S. aureus), biofilms are implicated in the resilience of chronic infections, presenting a serious clinical problem world-wide. Here, S. aureus biofilms are grown under flow within clinical catheters at 37 °C. The lipid composition and biophysical properties of lipid extracts from these biofilms are compared with those from exponential growth and stationary phase cells. Biofilms show a reduction in iso and anteiso branching compensated by an increase in saturated fatty acids compared to stationary phase. A drastic reduction in carotenoid levels is also observed during biofilm formation. Thermotropic measurements of Laurdan GP and DPH polarization, show a reduction of lipid packing at 37 °C for biofilms compared to stationary phase. We studied the effects of carotenoid content on DMPG and DPPG model membranes showing trends in thermotropic behavior consistent with those observed in bacterial isolates, indicating that carotenoids participate in modulating lipid packing. Additionally, bending elastic constant (kc) measurements using vesicle fluctuation analysis (VFA) show that the presence of carotenoids can increase membrane bending rigidity. The antimicrobial peptide Magainin H2 was less activity on liposomes composed of stationary phase compared to biofilms or exponential growth isolates. This study contributes to an understanding of how Staphylococcus aureus modulates the composition of its membrane lipids, and how those changes affect the biophysical properties of membranes, which in turn may play a role in its virulence and its resistance to different membrane-active antimicrobial agents.
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Affiliation(s)
- Maria Isabel Perez-Lopez
- Department of Physics, Universidad de los Andes, Bogotá, Colombia; Biological Sciences Department, Universidad de los Andes, Bogotá, Colombia
| | | | - Steve Trier
- Department of Physics, Universidad de los Andes, Bogotá, Colombia
| | - Cornelia Herrfurth
- Department of Plant Biochemistry, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Goettingen, Germany
| | - Ivo Feussner
- Department of Plant Biochemistry, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Goettingen, Germany; Department of Plant Biochemistry, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Adriana Bernal
- Biological Sciences Department, Universidad de los Andes, Bogotá, Colombia
| | | | - Chad Leidy
- Department of Physics, Universidad de los Andes, Bogotá, Colombia.
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Impact of Deficiencies in Branched-Chain Fatty Acids and Staphyloxanthin in Staphylococcus aureus. BIOMED RESEARCH INTERNATIONAL 2019; 2019:2603435. [PMID: 30805362 PMCID: PMC6362504 DOI: 10.1155/2019/2603435] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 12/24/2018] [Accepted: 01/06/2019] [Indexed: 12/18/2022]
Abstract
Staphylococcus aureus is a well-known human pathogen with the ability to cause mild superficial skin infections to serious deep-tissue infections, such as osteomyelitis, pneumonia, and infective endocarditis. A key to S. aureus infections and its pathogenicity is its ability to survive in adverse environments, especially at lower temperatures, by regulation of its cell membrane. Branched-chain fatty acids (BCFAs) and staphyloxanthin have been shown to regulate membrane fluidity and staphylococcal virulence. This study was conducted with the hypothesis that the simultaneous lack of BCFAs and staphyloxanthin will have a far greater implication on environmental survival and virulence of S. aureus. Lack of a functional branched-chain α-keto acid dehydrogenase (BKD) enzyme because of a mutation in the lpdA gene led to a decrease in the production of BCFAs, membrane fluidity, slower growth, and poor in vivo survival of S. aureus. A mutation in the crtM gene eliminated the production of staphyloxanthin but it did not affect membrane BCFA levels, fluidity, growth, or in vivo survival. A crtM:lpdA double mutant showed much slower growth and attenuation compared to individual mutants. The results of this study suggest that simultaneous targeting of the BCFA and staphyloxanthin biosynthetic pathways can be a strategy to control S. aureus infections.
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Adaptive Metabolism in Staphylococci: Survival and Persistence in Environmental and Clinical Settings. J Pathog 2018; 2018:1092632. [PMID: 30327733 PMCID: PMC6171259 DOI: 10.1155/2018/1092632] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/28/2018] [Accepted: 08/12/2018] [Indexed: 01/04/2023] Open
Abstract
Staphylococci are highly successful at colonizing a variety of dynamic environments, both nonpathogenic and those of clinical importance, and comprise the list of pathogens of global public health significance. Their remarkable survival and persistence can be attributed to a host of strategies, one of which is metabolic versatility—their ability to rapidly alter their metabolism in the presence of transient or long-term bacteriostatic and bactericidal conditions and facilitate cellular homeostasis. These attributes contribute to their widespread dissemination and challenging eradication particularly from clinical settings. The study of microbial behaviour at the metabolite level provides insight into mechanisms of survival and persistence under defined environmental and clinical conditions. This paper reviews the range of metabolic modulations that facilitate staphylococcal acclimatization and persistence in varying terrestrial and host conditions, and their public health ramifications in these settings.
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Branching Out: Alterations in Bacterial Physiology and Virulence Due to Branched-Chain Amino Acid Deprivation. mBio 2018; 9:mBio.01188-18. [PMID: 30181248 PMCID: PMC6123439 DOI: 10.1128/mbio.01188-18] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The branched-chain amino acids (BCAAs [Ile, Leu, and Val]) represent important nutrients in bacterial physiology, with roles that range from supporting protein synthesis to signaling and fine-tuning the adaptation to amino acid starvation. In some pathogenic bacteria, the adaptation to amino acid starvation includes induction of virulence gene expression: thus, BCAAs support not only proliferation during infection, but also the evasion of host defenses. The branched-chain amino acids (BCAAs [Ile, Leu, and Val]) represent important nutrients in bacterial physiology, with roles that range from supporting protein synthesis to signaling and fine-tuning the adaptation to amino acid starvation. In some pathogenic bacteria, the adaptation to amino acid starvation includes induction of virulence gene expression: thus, BCAAs support not only proliferation during infection, but also the evasion of host defenses. A body of research has accumulated over the years to describe the multifaceted physiological roles of BCAAs and the mechanisms bacteria use to maintain their intracellular levels. More recent studies have focused on understanding how fluctuations in their intracellular levels impact global regulatory pathways that coordinate the adaptation to nutrient limitation, especially in pathogenic bacteria. In this minireview, we discuss how these studies have refined the individual roles of BCAAs, shed light on how BCAA auxotrophy might promote higher sensitivity to exogenous BCAA levels, and revealed pathogen-specific responses to BCAA deprivation. These advancements improve our understanding of how bacteria meet their nutritional requirements for growth while simultaneously remaining responsive to changes in environmental nutrient availability to promote their survival in a range of environments.
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Indeglia PA, Georgieva AT, Krishna VB, Martyniuk CJ, Bonzongo JCJ. Toxicity of functionalized fullerene and fullerene synthesis chemicals. CHEMOSPHERE 2018; 207:1-9. [PMID: 29763761 DOI: 10.1016/j.chemosphere.2018.05.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 04/20/2018] [Accepted: 05/03/2018] [Indexed: 06/08/2023]
Abstract
Fullerene is one of the most studied carbon-based nanoparticles due to its unique structure and potential for diverse applications. This study focuses on toxicological effects of two fullerene nanomaterials, contributing to ecological as well as human risk assessment strategies. The biological responses from two basic fullerene materials, aqueous-nanoC60 and alkaline-synthesized fullerenol, were examined using four model organisms. Bioassays were conducted on bacteria (Pseudomonas aeruginosa and Staphylococcus aureus) to determine population impacts and to assess mechanisms of cellular effects for both Gram-negative and Gram-positive species. LC50 of aqu-nC60 stirred for 28 days for P. aeruginosa was estimated to be 1336 mg/L; however, toxicity of the same aqu-nC60 preparation for S. aureus was insignificant. Freshwater green algae Raphidocelus subcapitata and invertebrate Ceriodaphnia dubia were exposed to 28-day stirred aqu-nC60 with no significant toxicological impact. Aqu-nC60 stirred for 14 days bore no toxicity within two orders of magnitude greater than the highest concentration administered. LC50 for organisms exposed to alkaline-synthesized fullerenol prepared in the laboratory was 2409 mg/L for P. aeruginosa with no determinable toxicity to S. aureus, and 1462 mg/L and 45.2 mg/L for R. subcapitata and C. dubia, respectively. Toxicity thresholds for commercially-prepared fullerenol were lower for all species, an impact attributed to the presence of impurities. Mechanistic analysis of membrane damage on bacteria by laboratory-prepared fullerenol indicated necrotic and apoptotic responses with and without photoactivation. Toxicological responses from fullerenol synthesis by-products were only determinable for C. dubia with effects attributable to impurities.
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Affiliation(s)
- Paul A Indeglia
- University of Florida, Department of Environmental Engineering Sciences, Black Hall, Gainesville, FL 32611, USA.
| | | | - Vijay B Krishna
- University of Florida, Particle Engineering Research Center, FL, USA
| | | | - Jean-Claude J Bonzongo
- University of Florida, Department of Environmental Engineering Sciences, Black Hall, Gainesville, FL 32611, USA
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Interrelationships between Fatty Acid Composition, Staphyloxanthin Content, Fluidity, and Carbon Flow in the Staphylococcus aureus Membrane. Molecules 2018; 23:molecules23051201. [PMID: 29772798 PMCID: PMC6099573 DOI: 10.3390/molecules23051201] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/14/2018] [Accepted: 05/16/2018] [Indexed: 12/24/2022] Open
Abstract
Fatty acids play a major role in determining membrane biophysical properties. Staphylococcus aureus produces branched-chain fatty acids (BCFAs) and straight-chain saturated fatty acids (SCSFAs), and can directly incorporate exogenous SCSFAs and straight-chain unsaturated fatty acids (SCUFAs). Many S. aureus strains produce the triterpenoid pigment staphyloxanthin, and the balance of BCFAs, SCSFAs and staphyloxanthin determines membrane fluidity. Here, we investigated the relationship of fatty acid and carotenoid production in S. aureus using a pigmented strain (Pig1), its carotenoid-deficient mutant (Pig1ΔcrtM) and the naturally non-pigmented Staphylococcus argenteus that lacks carotenoid biosynthesis genes and is closely related to S. aureus. Fatty acid compositions in all strains were similar under a given culture condition indicating that staphyloxanthin does not influence fatty acid composition. Strain Pig1 had decreased membrane fluidity as measured by fluorescence anisotropy compared to the other strains under all conditions indicating that staphyloxanthin helps maintain membrane rigidity. We could find no evidence for correlation of expression of crtM and fatty acid biosynthesis genes. Supplementation of medium with glucose increased SCSFA production and decreased BCFA and staphyloxanthin production, whereas acetate-supplementation also decreased BCFAs but increased staphyloxanthin production. We believe that staphyloxanthin levels are influenced more through metabolic regulation than responding to fatty acids incorporated into the membrane.
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Crompton MJ, Dunstan RH. Evaluation of in-situ fatty acid extraction protocols for the analysis of staphylococcal cell membrane associated fatty acids by gas chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2018; 1084:80-88. [DOI: 10.1016/j.jchromb.2018.03.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/25/2018] [Accepted: 03/09/2018] [Indexed: 11/25/2022]
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PccD Regulates Branched-Chain Amino Acid Degradation and Exerts a Negative Effect on Erythromycin Production in Saccharopolyspora erythraea. Appl Environ Microbiol 2018; 84:AEM.00049-18. [PMID: 29439982 DOI: 10.1128/aem.00049-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 01/31/2018] [Indexed: 11/20/2022] Open
Abstract
Branched-chain amino acid (BCAA) degradation is a major source of propionyl coenzyme A (propionyl-CoA), a key precursor of erythromycin biosynthesis in Saccharopolyspora erythraea In this study, we found that the bkd operon, responsible for BCAA degradation, was regulated directly by PccD, a transcriptional regulator of propionyl-CoA carboxylase genes. The transcriptional level of the bkd operon was upregulated 5-fold in a pccD gene deletion strain (ΔpccD strain) and decreased 3-fold in a pccD overexpression strain (WT/pIB-pccD), demonstrating that PccD was a negative transcriptional regulator of the operon. The deletion of pccD significantly improved the ΔpccD strain's growth rate, whereas pccD overexpression repressed WT/pIB-pccD growth rate, in basic Evans medium with 30 mM valine as the sole carbon and nitrogen source. The deletion of gdhA1 and the BcdhE1 gene (genes in the bkd operon) resulted in lower growth rates of ΔgdhA1 and ΔBcdhE1 strains, respectively, on 30 mM valine, further suggesting that the bkd operon is involved in BCAA degradation. Both bkd overexpression (WT/pIB-bkd) and pccD inactivation (ΔpccD strain) improve erythromycin production (38% and 64%, respectively), whereas the erythromycin production of strain WT/pIB-pccD was decreased by 48%. Lastly, we explored the applications of engineering pccD and bkd in an industrial high-erythromycin-producing strain. pccD deletion in industrial strain S. erythraea E3 (E3pccD) improved erythromycin production by 20%, and the overexpression of bkd in E3ΔpccD (E3ΔpccD/pIB-bkd) increased erythromycin production by 39% compared with S. erythraea E3 in an industrial fermentation medium. Addition of 30 mM valine to industrial fermentation medium further improved the erythromycin production by 23%, a 72% increase from the initial strain S. erythraea E3.IMPORTANCE We describe a bkd operon involved in BCAA degradation in S. erythraea The genes of the operon are repressed by a TetR regulator, PccD. The results demonstrated that PccD controlled the supply of precursors for biosynthesis of erythromycin via regulating the BCAA degradation and propionyl-CoA assimilation and exerted a negative effect on erythromycin production. The findings reveal a regulatory mechanism in feeder pathways and provide new strategies for designing metabolic engineering to increase erythromycin yield.
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Regulatory and biosynthetic effects of the bkd gene clusters on the production of daptomycin and its analogs A21978C1–3. ACTA ACUST UNITED AC 2018; 45:271-279. [DOI: 10.1007/s10295-018-2011-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 01/11/2018] [Indexed: 01/10/2023]
Abstract
Abstract
Daptomycin is a cyclic lipopeptide antibiotic produced by Streptomyces roseosporus in an acidic peptide complex A21978C. In this complex, A21978C1–3 is most abundant and contains branched-chain fatty acyl groups, while daptomycin has a straight decanoic acyl group. The branched-chain α-keto acid dehydrogenase complex (BCDH complex), encoded by bkd gene clusters in Streptomyces, is responsible for the early step of converting branched-chain amino acids into branched-chain fatty acids. In a daptomycin industrial producer S. roseosporus L30, two alleles of bkd gene clusters, bkdA1B1C1/bkdA2B2C2, and a regulatory gene bkdR located upstream of bkdA2B2C2 are identified. We show that BkdR positively regulated bkdA2B2C2 expression and was negatively auto-regulated, but is not directly involved in regulation of daptomycin gene cluster expression. However, BkdR is required for both daptomycin and A21978C1–3 production. Furthermore, deletion of bkdA2B2C2 only led to partial reduction of A21978C1–3 production, while the ΔbkdA1B1C1 mutant shows very weak production of A21978C1–3, and the double bkd mutant has a similar production profile as the single ΔbkdA1B1C1 mutant, suggesting that bkdA1B1C1 gene cluster plays a dominant role in branched-chain fatty acid biosynthesis. So we reveal a unique regulatory function of BkdR and genetic engineered a bkd null strain for daptomycin production with reduced impurities.
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Singh VK, Sirobhushanam S, Ring RP, Singh S, Gatto C, Wilkinson BJ. Roles of pyruvate dehydrogenase and branched-chain α-keto acid dehydrogenase in branched-chain membrane fatty acid levels and associated functions in Staphylococcus aureus. J Med Microbiol 2018; 67:570-578. [PMID: 29498620 DOI: 10.1099/jmm.0.000707] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Membrane fluidity to a large extent is governed by the presence of branched-chain fatty acids (BCFAs). Branched-chain α-keto acid dehydrogenase (BKD) is the key enzyme in BCFA synthesis. A Staphylococcus aureus BKD-deficient strain still produced substantial levels of BCFAs. Pyruvate dehydrogenase (PDH) with structural similarity to BKD has been speculated to contribute to BCFAs in S. aureus. METHODOLOGY This study was carried out using BKD-, PDH- and BKD : PDH-deficient derivatives of methicillin-resistant S. aureus strain JE2. Differences in growth kinetics were evaluated spectrophotometrically, membrane BCFAs using gas chromatography and membrane fluidity by fluorescence polarization. Carotenoid levels were estimated by measuring A465 of methanol extracts from 48 h cultures. MIC values were determined by broth microdilution.Results/Key findings. BCFAs made up 50 % of membrane fatty acids in wild-type but only 31 % in the BKD-deficient mutant. BCFA level was ~80 % in the PDH-deficient strain and 38 % in the BKD : PDH-deficient strain. BKD-deficient mutant showed decreased membrane fluidity, the PDH-deficient mutant showed increased membrane fluidity. The BKD- and PDH-deficient strains grew slower and the BKD : PDH-deficient strain grew slowest at 37 °C. However at 20 °C, the BKD- and BKD : PDH-deficient strains grew only a little followed by autolysis of these cells. The BKD-deficient strain produced higher levels of staphyloxanthin. The PDH-deficient and BKD : PDH-deficient strains produced very little staphyloxanthin. The BKD-deficient strain showed increased susceptibility to daptomycin. CONCLUSION The BCFA composition of the cell membrane in S. aureus seems to significantly impact cell growth, membrane fluidity and resistance to daptomycin.
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Affiliation(s)
- Vineet K Singh
- Microbiology & Immunology, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA
| | - Sirisha Sirobhushanam
- Microbiology Group, School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Robert P Ring
- Microbiology & Immunology, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA
| | - Saumya Singh
- Microbiology & Immunology, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA
| | - Craig Gatto
- Microbiology Group, School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
| | - Brian J Wilkinson
- Microbiology Group, School of Biological Sciences, Illinois State University, Normal, IL 61790, USA
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Li KH, Yu YH, Dong HJ, Zhang WB, Ma JC, Wang HH. Biological Functions of ilvC in Branched-Chain Fatty Acid Synthesis and Diffusible Signal Factor Family Production in Xanthomonas campestris. Front Microbiol 2017; 8:2486. [PMID: 29312195 PMCID: PMC5733099 DOI: 10.3389/fmicb.2017.02486] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/29/2017] [Indexed: 12/16/2022] Open
Abstract
In bacteria, the metabolism of branched-chain amino acids (BCAAs) is tightly associated with branched-chain fatty acids (BCFAs) synthetic pathways. Although previous studies have reported on BCFAs biosynthesis, more detailed associations between BCAAs metabolism and BCFAs biosynthesis remain to be addressed. In this study, we deleted the ilvC gene, which encodes ketol-acid reductoisomerase in the BCAAs synthetic pathway, from the Xanthomonas campestris pv. campestris (Xcc) genome. We characterized gene functions in BCFAs biosynthesis and production of the diffusible signal factor (DSF) family signals. Disruption of ilvC caused Xcc to become auxotrophic for valine and isoleucine, and lose the ability to synthesize BCFAs via carbohydrate metabolism. Furthermore, ilvC mutant reduced the ability to produce DSF-family signals, especially branched-chain DSF-family signals, which might be the main reason for Xcc reduction of pathogenesis toward host plants. In this report, we confirmed that BCFAs do not have major functions in acclimatizing Xcc cells to low temperatures.
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Affiliation(s)
- Kai-Huai Li
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Yong-Hong Yu
- Guangdong Food and Drug Vocational College, Guangzhou, China
| | - Hui-Juan Dong
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Wen-Bin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Jin-Cheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
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Eibler D, Seyfried C, Vetter W. Enantioselectivity of anteiso-fatty acids in hitherto uninspected sample matrices. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1061-1062:233-239. [DOI: 10.1016/j.jchromb.2017.07.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/12/2017] [Accepted: 07/16/2017] [Indexed: 02/08/2023]
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Christo-Foroux E, Vallaeys T, Loux V, Dassa E, Deutscher J, Wandersman C, Livernois A, Hot C, Criscuolo A, Dauga C, Clermont D, Chesneau O. Manual and expert annotation of the nearly complete genome sequence of Staphylococcus sciuri strain ATCC 29059: A reference for the oxidase-positive staphylococci that supports the atypical phenotypic features of the species group. Syst Appl Microbiol 2017; 40:401-410. [PMID: 28890241 DOI: 10.1016/j.syapm.2017.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/30/2017] [Accepted: 07/03/2017] [Indexed: 11/30/2022]
Abstract
Staphylococcus sciuri is considered to be one of the most ancestral species in the natural history of the Staphylococcus genus that consists of 48 validly described species. It belongs to the basal group of oxidase-positive and novobiocin-resistant staphylococci that diverged from macrococci approximately 250 million years ago. Contrary to other groups, the S. sciuri species group has not developed host-specific colonization strategies. Genome analysis of S. sciuri ATCC 29059 provides here the first genetic basis for atypical traits that would support the switch between the free-living style and the infective state in animals and humans. From among the most remarkable features, it was noticed in this extensive study that there were a number of phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTS), almost twice as many as any other staphylococci, and the co-occurrence of mevalonate and non-mevalonate pathways for isoprenoid synthesis. The sequenced strain was devoid of the main virulence factors present in Staphylococcus aureus, although it exhibited numerous heme and iron acquisition systems, as well as crt and aldH genes necessary for gold pigment synthesis. The sensing and signaling networks, exemplified by a large and typical repertoire of two-component regulatory systems and a complete panel of master regulators, such as agr, rex, mgrA, rot, sarA and sarR genes, depict the background in which S. aureus virulence genes were later acquired. An additional sigma factor, a distinct set of electron transducer elements and many gene operons similar to those found in Bacillus spp. would constitute the most visible remnant links with Bacillaceae organisms.
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Affiliation(s)
- Eugene Christo-Foroux
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
| | - Tatiana Vallaeys
- Département de Biologie Ecologie, Université de Montpellier, CC 13002, Place Eugène Bataillon, 34095 Montpellier, France.
| | - Valentin Loux
- MaIAGE, INRA, Université Paris-Saclay, Domaine de Vilvert, 78352 Jouy-en-Josas, France.
| | - Elie Dassa
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Josef Deutscher
- CNRS, UMR 8261 Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Université Paris Diderot, Sorbonne-Paris-Cité, 13 rue Pierre et Marie Curie, Paris, France.
| | - Cécile Wandersman
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Aurélien Livernois
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France; Département de Biologie Ecologie, Université de Montpellier, CC 13002, Place Eugène Bataillon, 34095 Montpellier, France
| | - Chloe Hot
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Alexis Criscuolo
- Hub, Center for Bioinformatics, Biostatistics and Integrative Biology (C3BI), Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
| | - Catherine Dauga
- International Group of Data Analysis (IGDA), Center for Bioinformatics, Biostatistics and Integrative Biology (C3BI), Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
| | - Dominique Clermont
- Collection de l'Institut Pasteur (CIP), Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
| | - Olivier Chesneau
- Département de Microbiologie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
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Rehal RP, Marbach H, Hubbard AT, Sacranie AA, Sebastiani F, Fragneto G, Harvey RD. The influence of mild acidity on lysyl-phosphatidylglycerol biosynthesis and lipid membrane physico-chemical properties in methicillin-resistant Staphylococcus aureus. Chem Phys Lipids 2017. [DOI: 10.1016/j.chemphyslip.2017.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Yao J, Rock CO. Exogenous fatty acid metabolism in bacteria. Biochimie 2017; 141:30-39. [PMID: 28668270 DOI: 10.1016/j.biochi.2017.06.015] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/26/2017] [Indexed: 10/19/2022]
Abstract
Bacterial type II fatty acid synthesis (FASII) is a target for novel antibiotic development. All bacteria encode for mechanisms to incorporate exogenous fatty acids, and some bacteria can use exogenous fatty acids to bypass FASII inhibition. Bacteria encode three different mechanisms for activating exogenous fatty acids for incorporation into phospholipid synthesis. Exogenous fatty acids are converted into acyl-CoA in Gammaproteobacteria such as E. coli. Acyl-CoA molecules constitute a separate pool from endogenously synthesized acyl-ACP. Acyl-CoA can be used for phospholipid synthesis or broken down by β-oxidation, but cannot be used for lipopolysaccharide synthesis. Exogenous fatty acids are converted into acyl-ACP in some Gram-negative bacteria. The resulting acyl-ACP undergoes the same fates as endogenously synthesized acyl-ACP. Exogenous fatty acids are converted into acyl-phosphates in Gram-positive bacteria, and can be used for phospholipid synthesis or become acyl-ACP. Only the order Lactobacillales can use exogenous fatty acids to bypass FASII inhibition. FASII shuts down completely in presence of exogenous fatty acids in Lactobacillales, allowing Lactobacillales to synthesize phospholipids entirely from exogenous fatty acids. Inhibition of FASII cannot be bypassed in other bacteria because FASII is only partially down-regulated in presence of exogenous fatty acid or FASII is required to synthesize essential metabolites such as β-hydroxyacyl-ACP. Certain selective pressures such as FASII inhibition or growth in biofilms can select for naturally occurring one step mutations that attenuate endogenous fatty acid synthesis. Although attempts have been made to estimate the natural prevalence of these mutants, culture-independent metagenomic methods would provide a better estimate.
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Affiliation(s)
- Jiangwei Yao
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Charles O Rock
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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45
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Moon HJ, Min KJ, Park NY, Park HJ, Yoon KS. Survival of Staphylococcus aureus in dried fish products as a function of temperature. Food Sci Biotechnol 2017; 26:823-828. [PMID: 30263609 PMCID: PMC6049567 DOI: 10.1007/s10068-017-0096-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 02/23/2017] [Accepted: 03/02/2017] [Indexed: 10/19/2022] Open
Abstract
We evaluated the survival ability of Staphylococcus aureus and the production of Staphylococcal enterotoxin A (SEA) in dried filefishes and julienned squid at 10°, 24°, and 35 °C for 5 months. S. aureus survived longer at 10 °C than 24° and 35 °C, and better in dried julienned squid than dried filefishes. At 35 °C, the populations of S. aureus were rapidly diminished and undetectable in dried filefishes and julienned squid after 14 and 19 days, respectively. SEA production did not increase during the 5-month storage period, regardless of the temperature and type of dried fish products. Although it is advised to store dried fish products at 10 °C for quality control in retail markets, refrigerated temperature is more likely to facilitate the survival of S. aureus in dried fish products. Thus, dried fish products should be produced and stored under hygienic conditions.
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Affiliation(s)
- Hye-Jin Moon
- Department of Food and Nutrition, Kyung Hee University, Seoul, 02447 Republic of Korea
| | - Kyung-Jin Min
- Department of Food and Nutrition, Jang An University, Hwaseong, Gyeonggi 18331 Republic of Korea
| | - Na-Yoon Park
- Department of Food and Nutrition, Kyung Hee University, Seoul, 02447 Republic of Korea
| | - Hee-Jin Park
- Department of Food and Nutrition, Kyung Hee University, Seoul, 02447 Republic of Korea
| | - Ki-Sun Yoon
- Department of Food and Nutrition, Kyung Hee University, Seoul, 02447 Republic of Korea
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Dhali D, Coutte F, Arias AA, Auger S, Bidnenko V, Chataigné G, Lalk M, Niehren J, de Sousa J, Versari C, Jacques P. Genetic engineering of the branched fatty acid metabolic pathway ofBacillus subtilisfor the overproduction of surfactin C14isoform. Biotechnol J 2017; 12. [DOI: 10.1002/biot.201600574] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/13/2017] [Accepted: 03/31/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Debarun Dhali
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale; EA 7394 - ICV - Institut Charles Viollette; Lille France
| | - François Coutte
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale; EA 7394 - ICV - Institut Charles Viollette; Lille France
| | - Anthony Argüelles Arias
- MiPI, TERRA Research Centre, Gembloux Agro-Bio Tech; University of Liege; Passage des Déportés; Gembloux Belgium
| | - Sandrine Auger
- Micalis Institute, INRA, AgroParisTech; University Paris-Saclay; Jouy-en-Josas France
| | - Vladimir Bidnenko
- Micalis Institute, INRA, AgroParisTech; University Paris-Saclay; Jouy-en-Josas France
| | - Gabrielle Chataigné
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale; EA 7394 - ICV - Institut Charles Viollette; Lille France
| | - Michael Lalk
- Ernst-Moritz-Arndt-University Greifswald; Institute of Biochemistry; Greifswald Germany
| | - Joachim Niehren
- University Lille; BioComputing Team, CRIStAL Lab (CNRS UMR9189); Villeneuve d'Ascq France
- Inria Lille; Villeneuve d'Ascq France
| | - Joana de Sousa
- Ernst-Moritz-Arndt-University Greifswald; Institute of Biochemistry; Greifswald Germany
| | - Cristian Versari
- University Lille; BioComputing Team, CRIStAL Lab (CNRS UMR9189); Villeneuve d'Ascq France
| | - Philippe Jacques
- University Lille, INRA, ISA, University Artois, University Littoral Côte d'Opale; EA 7394 - ICV - Institut Charles Viollette; Lille France
- MiPI, TERRA Research Centre, Gembloux Agro-Bio Tech; University of Liege; Passage des Déportés; Gembloux Belgium
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Eibler D, Abdurahman H, Ruoff T, Kaffarnik S, Steingass H, Vetter W. Unexpected Formation of Low Amounts of (R)-Configurated anteiso-Fatty Acids in Rumen Fluid Experiments. PLoS One 2017; 12:e0170788. [PMID: 28129363 PMCID: PMC5271357 DOI: 10.1371/journal.pone.0170788] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 01/11/2017] [Indexed: 01/26/2023] Open
Abstract
Anteiso-fatty acids (aFA) with odd carbon number are a class of branched-chain fatty acids (BCFA) mainly produced by bacteria. Bacterial sources are also made responsible for their occurrence in the low percent-range in lipids of ruminants (meat and milk) and fish. aFAs are chiral molecules and typically occur predominantly in form of (S)-enantiomers, and their primary precursor has been noted to be isoleucine. Yet, low proportions of (R)-aFAs were also detected in fish and cheese samples. Here we investigated the potential formation of (R)-aFAs by means of incubation experiments with rumen fluid from fistulated cows. Supplementation of rumen fluid with both L- and DL-isoleucine, resulted in a significant (α <0.05) increase of the aFA concentrations but in both cases enantiopure (S)-aFAs were observed. By contrast, incubations without addition of any isoleucine lead to a significant (α <0.05) formation of small proportions of (R)-aFAs similarly to those previously observed in fish and cheese. These results were consistently reproduced in three different years with rumen fluid from different cows fed different diets. All findings point to the existence of a further biosynthesis pathway of aFAs with different stereospecificity than the classic one using isoleucine as primer.
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Affiliation(s)
- Dorothee Eibler
- University of Hohenheim, Institute of Food Chemistry (170b), Stuttgart, Germany
| | - Halima Abdurahman
- University of Hohenheim, Institute of Food Chemistry (170b), Stuttgart, Germany
| | - Tanja Ruoff
- University of Hohenheim, Institute of Food Chemistry (170b), Stuttgart, Germany
| | - Stefanie Kaffarnik
- University of Hohenheim, Institute of Food Chemistry (170b), Stuttgart, Germany
| | - Herbert Steingass
- University of Hohenheim, Institute of Animal Science (460a), Stuttgart, Germany
| | - Walter Vetter
- University of Hohenheim, Institute of Food Chemistry (170b), Stuttgart, Germany
- * E-mail:
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Lee J, Gwak E, Ha J, Kim S, Lee S, Lee H, Oh MH, Park BY, Oh NS, Choi KH, Yoon Y. Mathematical Model for Predicting the Growth Probability of Staphylococcus aureus in Combinations of NaCl and NaNO 2 under Aerobic or Evacuated Storage Conditions. Korean J Food Sci Anim Resour 2017; 36:752-759. [PMID: 28115886 PMCID: PMC5243959 DOI: 10.5851/kosfa.2016.36.6.752] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/28/2016] [Accepted: 11/05/2016] [Indexed: 11/06/2022] Open
Abstract
The objective of this study was to describe the growth patterns of Staphylococcus aureus in combinations of NaCl and NaNO2, using a probabilistic model. A mixture of S. aureus strains (NCCP10826, ATCC13565, ATCC14458, ATCC23235, and ATCC27664) was inoculated into nutrient broth plus NaCl (0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, and 1.75%) and NaNO2 (0, 15, 30, 45, 60, 75, 90, 105, and 120 ppm). The samples were then incubated at 4, 7, 10, 12 and 15℃ for up to 60 d under aerobic or vacuum conditions. Growth responses [growth (1) or no growth (0)] were then determined every 24 h by turbidity, and analyzed to select significant parameters (p<0.05) by a stepwise selection method, resulting in a probabilistic model. The developed models were then validated with observed growth responses. S. aureus growth was observed only under aerobic storage at 10-15℃. At 10-15℃, NaCl and NaNO2 did not inhibit S. aureus growth at less than 1.25% NaCl. Concentration dependency was observed for NaCl at more than 1.25%, but not for NaNO2. The concordance percentage between observed and predicted growth data was approximately 93.86%. This result indicates that S. aureus growth can be inhibited in vacuum packaging and even aerobic storage below 10℃. Furthermore, NaNO2 does not effectively inhibit S. aureus growth.
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Affiliation(s)
- Jeeyeon Lee
- Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea; Risk Analysis Research Center, Sookmyung Women's University, Seoul 04310, Korea
| | - Eunji Gwak
- Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea
| | - Jimyeong Ha
- Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea; Risk Analysis Research Center, Sookmyung Women's University, Seoul 04310, Korea
| | - Sejeong Kim
- Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea; Risk Analysis Research Center, Sookmyung Women's University, Seoul 04310, Korea
| | - Soomin Lee
- Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea; Risk Analysis Research Center, Sookmyung Women's University, Seoul 04310, Korea
| | - Heeyoung Lee
- Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea; Risk Analysis Research Center, Sookmyung Women's University, Seoul 04310, Korea
| | - Mi-Hwa Oh
- National Institute of Animal Science, RDA, Wanju 55365, Korea
| | - Beom-Young Park
- National Institute of Animal Science, RDA, Wanju 55365, Korea
| | - Nam Su Oh
- R&D Center, Seoul Dairy Cooperative, Ansan 15407, Korea
| | - Kyoung-Hee Choi
- Department of Oral Microbiology, College of Dentistry, Wonkwang University, Iksan 54538, Korea
| | - Yohan Yoon
- Department of Food and Nutrition, Sookmyung Women's University, Seoul 04310, Korea; Risk Analysis Research Center, Sookmyung Women's University, Seoul 04310, Korea
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Sirobhushanam S, Galva C, Saunders LP, Sen S, Jayaswal R, Wilkinson BJ, Gatto C. Utilization of multiple substrates by butyrate kinase from Listeria monocytogenes. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:283-290. [PMID: 27940001 DOI: 10.1016/j.bbalip.2016.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 11/20/2016] [Accepted: 12/04/2016] [Indexed: 12/17/2022]
Abstract
Listeria monocytogenes, the causative agent of listeriosis, can build up to dangerous levels in refrigerated foods potentially leading to expensive product recalls. An important aspect of the bacterium's growth at low temperatures is its ability to increase the branched-chain fatty acid anteiso C15:0 content of its membrane at lower growth temperatures, which imparts greater membrane fluidity. Mutants in the branched-chain α-keto dehydrogenase (bkd) complex are deficient in branched-chain fatty acids (BCFAs,) but these can be restored by feeding C4 and C5 branched-chain carboxylic acids (BCCAs). This suggests the presence of an alternate pathway for production of acyl CoA precursors for fatty acid biosynthesis. We hypothesize that the alternate pathway is composed of butyrate kinase (buk) and phosphotransbutyrylase (ptb) encoded in the bkd complex which produce acyl CoA products by their sequential action through the metabolism of carboxylic acids. We determined the steady state kinetics of recombinant His-tagged Buk using 11 different straight-chain and BCCA substrates in the acyl phosphate forming direction. Buk demonstrated highest catalytic efficiency with pentanoate as the substrate. Low product formation observed with acetate (C2) and hexanoate (C6) as the substrates indicates that Buk is not involved in either acetate metabolism or long chain carboxylic acid activation. We were also able to show that Buk catalysis occurs through a ternary complex intermediate. Additionally, Buk demonstrates a strong preference for BCCAs at low temperatures. These results indicate that Buk may be involved in the activation and assimilation of exogenous carboxylic acids for membrane fatty acid biosynthesis.
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Affiliation(s)
- Sirisha Sirobhushanam
- School of Biological Sciences, Illinois State University, Normal, IL 61790, United States
| | - Charitha Galva
- School of Biological Sciences, Illinois State University, Normal, IL 61790, United States
| | - Lauren P Saunders
- School of Biological Sciences, Illinois State University, Normal, IL 61790, United States
| | - Suranjana Sen
- School of Biological Sciences, Illinois State University, Normal, IL 61790, United States
| | - Radheshyam Jayaswal
- School of Biological Sciences, Illinois State University, Normal, IL 61790, United States
| | - Brian J Wilkinson
- School of Biological Sciences, Illinois State University, Normal, IL 61790, United States
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, IL 61790, United States.
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50
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Enoyl-Acyl Carrier Protein Reductase I (FabI) Is Essential for the Intracellular Growth of Listeria monocytogenes. Infect Immun 2016; 84:3597-3607. [PMID: 27736774 DOI: 10.1128/iai.00647-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/02/2016] [Indexed: 12/28/2022] Open
Abstract
Enoyl-acyl carrier protein reductase catalyzes the last step in each elongation cycle of type II bacterial fatty acid synthesis and is a key regulatory protein in bacterial fatty acid synthesis. Genes of the facultative intracellular pathogen Listeria monocytogenes encode two functional enoyl-acyl carrier protein isoforms based on their ability to complement the temperature-sensitive growth phenotype of Escherichia coli strain JP1111 [fabI(Ts)]. The FabI isoform was inactivated by the FabI selective inhibitor AFN-1252, but the FabK isoform was not affected by the drug, as expected. Inhibition of FabI by AFN-1252 decreased endogenous fatty acid synthesis by 80% and lowered the growth rate of L. monocytogenes in laboratory medium. Robust exogenous fatty acid incorporation was not detected in L. monocytogenes unless the pathway was partially inactivated by AFN-1252 treatment. However, supplementation with exogenous fatty acids did not restore normal growth in the presence of AFN-1252. FabI inactivation prevented the intracellular growth of L. monocytogenes, showing that neither FabK nor the incorporation of host cellular fatty acids was sufficient to support the intracellular growth of L. monocytogenes Our results show that FabI is the primary enoyl-acyl carrier protein reductase of type II bacterial fatty acid synthesis and is essential for the intracellular growth of L. monocytogenes.
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