Growth-Environment Dependent Modulation of Staphylococcus aureus Branched-Chain to Straight-Chain Fatty Acid Ratio and Incorporation of Unsaturated Fatty Acids

Sen, Suranjana; Sirobhushanam, Sirisha; Johnson, Seth R.; Song, Yang; Tefft, Ryan; Gatto, Craig; Wilkinson, Brian J.

doi:10.1371/journal.pone.0165300

Cited by 84 publications

(145 citation statements)

References 74 publications

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“…In S. aureus, BCFAs comprise 44 to 63% of the membrane and a BCFA-deficient strain exhibits reduced adherence to host cells and is attenuated in vivo (107, 145, 146). …”

Section: Bcaas At the Crossroads Of Metabolism And Virulencementioning

confidence: 99%

Branching Out: Alterations in Bacterial Physiology and Virulence Due to Branched-Chain Amino Acid Deprivation

Kaiser

Heinrichs

2018

mBio

100

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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.

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“…In S. aureus, BCFAs comprise 44 to 63% of the membrane and a BCFA-deficient strain exhibits reduced adherence to host cells and is attenuated in vivo (107, 145, 146). …”

Section: Bcaas At the Crossroads Of Metabolism And Virulencementioning

confidence: 99%

Branching Out: Alterations in Bacterial Physiology and Virulence Due to Branched-Chain Amino Acid Deprivation

Kaiser

Heinrichs

2018

mBio

100

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“…A paper in 2011 [11] reported that the 2-position is exclusively occupied by 15:0 fatty acids even in presence of millimolar concentrations of 18:1, while a paper in 2016 [77] reported that branched-chain fatty acids were reduced to less than 40% of the total cellular acyl chain composition so 16:0 and 18:1 is assumed to make up at least 10% of the 2-position composition. The difference between these two papers is what was measured and how it was measured.…”

Section: Pathways For Exogenous Fatty Acid Incorporationmentioning

confidence: 99%

“…It was found that all phosphatidylglycerol species contained 15:0 fatty acids. In contrast, Sen and coworkers [77] performed gas chromatography analysis on fatty acid methyl esters generated from hydrolyzing the total lipid extracts. Because lipid extracts contain non-phospholipid components like staphyloxanthin and media components such as free fatty acids and lipoproteins adsorbed to the bacterial cell surface, this form of analysis is less accurate at measuring phospholipid acyl chain composition.…”

Section: Pathways For Exogenous Fatty Acid Incorporationmentioning

confidence: 99%

Exogenous fatty acid metabolism in bacteria

2017

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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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“…Notably this was due to a reduced proportion of anteiso-branched chain fatty acids, as the proportion of iso-branched chains remained similar between the strains (Fig 1B). Overall, the fatty acid composition of these strains closely matched those of other S. aureus strains cultured in Müller-Hinton broth [26].…”

Section: Resultsmentioning

confidence: 82%

Characterisation ofStaphylococcus aureuslipids by nanoelectrospray ionisation tandem mass spectrometry (nESI-MS/MS)

Young

Desbois

Coote

et al. 2019

Preprint

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19Staphylococcus aureus is a major opportunistic pathogen that is exposed to antimicrobial 20 innate immune effectors and antibiotics that can disrupt its cell membrane. An 21 understanding of S. aureus lipid composition and its role in defending the cell against 22 validated the molecular characterization and showed the principal species present in each 33 strain were predominately anteiso-and iso-branched chain fatty acids. Though the fatty acid 34 and lipid profiles were similar between the S. aureus strains, this method was sufficiently 35 sensitive to distinguish minor differences in lipid composition. In conclusion, this nESI-36 MS/MS methodology can characterise the role of lipids in antimicrobial resistance, and may 37 even be applied to the rapid diagnosis of drug-resistant strains in the clinic. 38 3 39 101 102 6 103 Materials and methods 104 S. aureus culture and lipid extraction 105 All reagents and culture media were purchased from Sigma-Aldrich Ltd. S. aureus Newman 106 (methicillin-susceptible; MSSA), BB270 (methicillin-resistant; MRSA) and Mu50 (MRSA and 107 vancomycin intermediate-resistant) were sourced and cultured in Müller-Hinton broth as 108 described previously [22]. Briefly, each bacterial strain was prepared by inoculation of a 109 colony from an agar plate into 10 ml Müller-Hinton broth and cultured at 37°C with shaking 110 until reaching an OD 600nm = 1 (~1 × 10 9 colony-forming units [cfu]). Bacterial cells were 111 harvested (1000 × g, 10 min), washed in PBS before a repeat centrifugation and removal of 112 the supernatant. Lipids were extracted according to the Bligh-Dyer method [23], dried under 113 nitrogen, and stored at 4°C until analysis by mass spectrometry. 114 115 157

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Growth-Environment Dependent Modulation of Staphylococcus aureus Branched-Chain to Straight-Chain Fatty Acid Ratio and Incorporation of Unsaturated Fatty Acids

Cited by 84 publications

References 74 publications

Branching Out: Alterations in Bacterial Physiology and Virulence Due to Branched-Chain Amino Acid Deprivation

Branching Out: Alterations in Bacterial Physiology and Virulence Due to Branched-Chain Amino Acid Deprivation

Exogenous fatty acid metabolism in bacteria

Characterisation ofStaphylococcus aureuslipids by nanoelectrospray ionisation tandem mass spectrometry (nESI-MS/MS)

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