scholarly journals Exogenous Fatty Acids Remodel Staphylococcus aureus Lipid Composition through Fatty Acid Kinase

2020 ◽  
Vol 202 (14) ◽  
Author(s):  
Zachary DeMars ◽  
Vineet K. Singh ◽  
Jeffrey L. Bose
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Lipid Composition ◽  
Unsaturated Fatty Acids ◽  
Mouse Skin ◽  
Membrane Composition ◽  
Wild Type ◽  
Content Type

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.

scholarly journals Enterococcus faecalisEncodes an Atypical Auxiliary Acyl Carrier Protein Required for Efficient Regulation of Fatty Acid Synthesis by Exogenous Fatty Acids

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Lei Zhu ◽  
Qi Zou ◽  
Xinyun Cao ◽  
John E. Cronan
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Type Strain ◽  
Wild Type Strain ◽  
De Novo ◽  
Acid Synthesis ◽  
Wild Type ◽  
Content Type

ABSTRACTAcyl carrier proteins (ACPs) play essential roles in the synthesis of fatty acids and transfer of long fatty acyl chains into complex lipids. TheEnterococcus faecalisgenome contains two annotatedacpgenes, calledacpAandacpB. AcpA is encoded within the fatty acid synthesis (fab) operon and appears essential. In contrast, AcpB is an atypical ACP, having only 30% residue identity with AcpA, and is not essential. Deletion ofacpBhas no effect onE. faecalisgrowth orde novofatty acid synthesis in media lacking fatty acids. However, unlike the wild-type strain, where growth with oleic acid resulted in almost complete blockage ofde novofatty acid synthesis, theΔacpBstrain largely continuedde novofatty acid synthesis under these conditions. Blockage in the wild-type strain is due to repression offaboperon transcription, leading to levels of fatty acid synthetic proteins (including AcpA) that are insufficient to supportde novosynthesis. Transcription of thefaboperon is regulated by FabT, a repressor protein that binds DNA only when it is bound to an acyl-ACP ligand. Since AcpA is encoded in thefaboperon, its synthesis is blocked when the operon is repressed andacpAthus cannot provide a stable supply of ACP for synthesis of the acyl-ACP ligand required for DNA binding by FabT. In contrast to AcpA,acpBtranscription is unaffected by growth with exogenous fatty acids and thus provides a stable supply of ACP for conversion to the acyl-ACP ligand required for repression by FabT. Indeed,ΔacpBandΔfabTstrains have essentially the samede novofatty acid synthesis phenotype in oleic acid-grown cultures, which argues that neither strain can form the FabT-acyl-ACP repression complex. Finally, acylated derivatives of both AcpB and AcpA were substrates for theE. faecalisenoyl-ACP reductases and forE. faecalisPlsX (acyl-ACP; phosphate acyltransferase).IMPORTANCEAcpB homologs are encoded by many, but not all, lactic acid bacteria (Lactobacillales), including many members of the human microbiome. The mechanisms regulating fatty acid synthesis by exogenous fatty acids play a key role in resistance of these bacteria to those antimicrobials targeted at fatty acid synthesis enzymes. Defective regulation can increase resistance to such inhibitors and also reduce pathogenesis.

scholarly journals DNA Binding and Sensor Specificity of FarR, a Novel TetR Family Regulator Required for Induction of the Fatty Acid Efflux Pump FarE in Staphylococcus aureus

2018 ◽  
Vol 201 (3) ◽  
Author(s):  
Heba Alnaseri ◽  
Robert C. Kuiack ◽  
Katherine A. Ferguson ◽  
James E. T. Schneider ◽  
David E. Heinrichs ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Fatty Acid ◽  
Dna Binding ◽  
Unsaturated Fatty Acids ◽  
Efflux Pump ◽  
Ectopic Expression ◽  
Exogenous Fatty Acid ◽  
Content Type ◽  
Tetr Family Regulator

ABSTRACT Divergent genes in Staphylococcus aureus USA300 encode the efflux pump FarE and TetR family regulator FarR, which confer resistance to antimicrobial unsaturated fatty acids. To study their regulation, we constructed USA300 ΔfarER, which exhibited a 2-fold reduction in MIC of linoleic acid. farE expressed from its native promoter on pLIfarE conferred increased resistance to USA300 but not USA300 ΔfarER. Complementation of USA300 ΔfarER with pLIfarR also had no effect, whereas resistance was restored with pLIfarER or through ectopic expression of farE. In electrophoretic mobility shift assays, FarR bound to three different oligonucleotide probes that each contained a TAGWTTA motif, occurring as (i) a singular motif overlapping the −10 element of the PfarR promoter, (ii) in palindrome PAL1 immediately in the 3′ direction of PfarR, or (iii) within PAL2 upstream of the predicted PfarE promoter. FarR autorepressed its expression through cooperative binding to PAL1 and the adjacent TAGWTTA motif in PfarR. Consistent with reports that S. aureus does not metabolize fatty acids through acyl coenzyme A (acyl-CoA) intermediates, DNA binding activity of FarR was not affected by linoleoyl-CoA. Conversely, induction of farE required fatty acid kinase FakA, which catalyzes the first metabolic step in the incorporation of unsaturated fatty acids into phospholipid. We conclude that FarR is needed to promote the expression of farE while strongly autorepressing its own expression, and our data are consistent with a model whereby FarR interacts with a FakA-dependent product of exogenous fatty acid metabolism to ensure that efflux only occurs when the metabolic capacity for incorporation of fatty acid into phospholipid is exceeded. IMPORTANCE Here, we describe the DNA binding and sensor specificity of FarR, a novel TetR family regulator (TFR) in Staphylococcus aureus. Unlike the majority of TFRs that have been characterized, which function to repress a divergently transcribed gene, we find that FarR is needed to promote expression of the divergently transcribed farE gene, encoding a resistance-nodulation-division (RND) family efflux pump that is induced in response to antimicrobial unsaturated fatty acids. Induction of farE was dependent on the function of the fatty acid kinase FakA, which catalyzes the first metabolic step in the incorporation of exogenous unsaturated fatty acids into phospholipid. This represents a novel example of TFR function.

scholarly journals Antioxidant and fatty acid profile of gabiroba seed (Campomanesisa Xanthocarpa Berg)

2012 ◽  
Vol 32 (2) ◽  
pp. 234-238 ◽  
Author(s):  
Marli da Silva Santos ◽  
Obdulio Gomes Miguel ◽  
Carmen Lúcia Oliveira Petkowicz ◽  
Lys Mary Bileski Cândido
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Fatty Acid Profile ◽  
Unsaturated Fatty Acids ◽  
Ethanol Extract ◽  
Solvent Polarity ◽  
Antioxidant Potential ◽  
Total Phenolic ◽  
Total Phenolic Compounds

This study aimed to evaluate the antioxidant potential and fatty acid profile of gabiroba (Campomanesia xanthocarpa Berg) seeds. In order to obtain the extract, the seeds were dried, crushed, and subjected to sequential extraction by maceration and percolation in a modified soxhlet extractor using solvent polarity gradient composed of hexane, chloroform, ethyl acetate, and alcohol, respectively. The extraction time was six hours. The ethanol extract showed the highest antioxidant potential, given by the EC50 value and the amount of total phenolic compounds. High amounts of unsaturated fatty acids were found in the oil studied, especially the oleic acid.

Enterotoxin B production by Staphylococcus aureus under controlled fatty acid nutrition induced by cerulenin

1977 ◽  
Vol 23 (9) ◽  
pp. 1145-1150 ◽  
Author(s):  
Robert A. Altenbern
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Fatty Acid ◽  
Membrane Fluidity ◽  
Unsaturated Fatty Acid ◽  
Unsaturated Fatty Acids ◽  
Basal Medium ◽  
Aureus Strain ◽  
Enterotoxin B ◽  
Fatty Acid Supplement

Cells of Staphylococcus aureus, strain S-6, can grow in the presence of 100 μg of cerulenin/ml if the basal medium is supplemented with certain saturated or unsaturated fatty acids. The production of enterotoxin B (SEB) is markedly influenced by both the ratio of saturated to unsaturated fatty acid and by the melting point of the unsaturated fatty acid supplement. The results presented suggest that a certain degree of membrane fluidity promotes maximum SEB production and that greater or lesser degrees of membrane fluidity prohibit substantial SEB formation but fail to affect final growth density.

EXTH-27. MOLECULAR CHARACTERIZATION AND PRECLINICAL DEVELOPMENT OF NOVEL SMALL MOLECULE INHIBITOR SPECIFIC FOR WILD-TYPE IDH1 FOR FERROPTOSIS INDUCTION IN GLIOBLASTOMA

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi169-vi169
Author(s):  
Kevin Murnan ◽  
Serena Tommasini-Ghelfi ◽  
Lisa Hurley ◽  
Corey Dussold ◽  
Daniel Wahl ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Cell Death ◽  
Plasma Membrane ◽  
Fatty Acid ◽  
Unsaturated Fatty Acids ◽  
De Novo ◽  
De Novo Lipogenesis ◽  
Therapeutic Modality ◽  
Wild Type ◽  
Genetic Ablation

Abstract Increased de novo synthesis, mobilization and uptake of fatty acids are required to provide sufficient lipids for membrane biogenesis in support of rapid tumor cell division and growth. In addition to their structural roles as components of the plasma membrane, fatty acid-derived lipids regulate ferroptotic cell death, a type of programmed cell death, when oxidized by iron-dependent lipoxygenase enzymes. De novo lipogenesis and the defense against oxidative lipid damage require large amounts of cytosolic NADPH. Our group has recently found that HGG up-regulate wild-type Isocitrate dehydrogenase 1 (referred to hereafter as ‘wt-IDH1high HGG’) to generate large quantities of cytosolic NADPH. RNAi-mediated knockdown of wt-IDH1, alone and in combination with radiation therapy (RT), slows the growth of patient-derived HGG xenografts, while overexpression of wt-IDH1 promotes intracranial HGG growth. Isotope tracer and liquid chromatography-based lipidomic studies indicated that wt-IDH1 supports the de novo biosynthesis of mono-unsaturated fatty acids (MUFAs) and promotes the incorporation of monounsaturated phospholipids into the plasma membrane, while displacing polyunsaturated fatty acid (PUFA) phospholipids. In addition, enhanced NADPH production in wt-IDH1high HGG increases glutathione (GSH) level, reduces reactive oxygen species (ROS), activates the phospholipid peroxidase glutathione peroxidase 4 (GPX4)-driven lipid repair pathway, and dampens the accumulation of PUFA-containing lipid peroxides, known executioners of ferroptosis. To pharmacologically target wt-IDH1,we have used and characterized wt-IDH1i-13, a first-in-class competitive α,β-unsaturated enone (AbbVie). wt-IDH1i-13 potently inhibits wt-IDH1 enzymatic activity, by covalently binding to the NADP+ binding pocket. Our data indicate that wt-IDH1i-13 promotes ferroptosis, which can be rescued by pre-treatment of cells with the peroxyl scavenger and ferroptosis inhibitor ferrostatin. wt-IDH1i-13 is brain-penetrant, and similar to genetic ablation, reduces progression and extends the survival of wt-IDH1high HGG bearing mice, alone and in combination with RT. These studies credential to wt-IDH1i-13 as a novel therapeutic modality for the treatment of wt-IDH1 gliomas.

ERUCIC ACID AND CHOLESTEROL EXCRETION IN THE RAT

1956 ◽  
Vol 34 (1) ◽  
pp. 981-991 ◽  
Author(s):  
K. K. Carroll ◽  
R. L. Noble
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Erucic Acid ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Fraction ◽  
Cholesterol Concentration ◽  
Acid Fraction ◽  
Cholesterol Excretion ◽  
Fecal Cholesterol

Erucic acid has been found to increase the excretion of endogenously produced cholesterol in the rat with little change in the cholesterol concentration in the carcass except for increased concentrations in the adrenals and liver. The fecal cholesterol was identified by melting point and infrared spectrum after isolation by chromatography on alumina. It does not appear to originate in the liver since no increase was observed in the biliary excretion of cholesterol. Other homologues of oleic acid, namely eicosenoic and nervonic acid, produced similar changes in fecal cholesterol excretion, although oleic acid itself had little effect. A series of saturated fatty acids from butyric (C4) to behenic (C22) were tested and the longer chain members found to cause some increase in cholesterol excretion. Ester cholesterol accounted for much of the observed increases but varied greatly in the experiments with unsaturated fatty acids. A preparation of cerebrosides from beef spinal cord also increased the amount of cholesterol excreted in the feces. The fatty acid fraction from this preparation gave a similar result, although the cerebrosides gave rise mainly to free cholesterol and the fatty acid fraction to ester cholesterol.

scholarly journals Two Lipid Signals Guide Fruiting Body Development of Myxococcus xanthus

mBio ◽  
2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Swapna Bhat ◽  
Tilman Ahrendt ◽  
Christina Dauth ◽  
Helge B. Bode ◽  
Lawrence J. Shimkets
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fruiting Body ◽  
Myxococcus Xanthus ◽  
Chain Fatty Acid ◽  
Fatty Alcohols ◽  
Lipid Bodies ◽  
Wild Type ◽  
Bioactive Lipids ◽  
Content Type

ABSTRACTMyxococcus xanthusproduces several extracellular signals that guide fruiting body morphogenesis and spore differentiation. Mutants defective in producing a signal may be rescued by codevelopment with wild-type cells or cell fractions containing the signal. In this paper, we identify two molecules that rescue development of the E signal-deficient mutant LS1191 at physiological concentrations,iso15:0 branched-chain fatty acid (FA) and 1-iso15:0-alkyl-2,3-di-iso15:0-acyl glycerol (TG1), a development-specific monoalkyl-diacylglycerol. The physiological concentrations of the bioactive lipids were determined by mass spectrometry from developing wild-type cells using chemically synthesized standards. Synthetic TG1 restored fruiting body morphogenesis and sporulation and activated the expression of the developmentally regulated gene with locus tagMXAN_2146at physiological concentrations, unlike its nearly identical tri-iso15:0 triacylglycerol (TAG) counterpart, which has an ester linkage instead of an ether linkage.iso15:0 FA restored development at physiological concentrations, unlike palmitic acid, a straight-chain fatty acid. The addition of either lipid stimulates cell shortening, with an 87% decline in membrane surface area, concomitantly with the production of lipid bodies at each cell pole and in the center of the cell. We suggest that cells produce triacylglycerol from membrane phospholipids. Bioactive lipids may be released byprogrammedcelldeath (PCD), which claims up to 80% of developing cells, since cells undergoing PCD produce lipid bodies before lysing.IMPORTANCELike mammalian adipose tissue, many of theM. xanthuslipid body lipids are triacylglycerols (TAGs), containing ester-linked fatty acids. In both systems, ester-linked fatty acids are retrieved from TAGs with lipases and consumed by the fatty acid degradation cycle. Both mammals andM. xanthusalso produce lipids containing ether-linked fatty alcohols with alkyl or vinyl linkages, such as plasmalogens. Alkyl and vinyl linkages are not hydrolyzed by lipases, and no clear role has emerged for lipids bearing them. For example, plasmalogen deficiency in mice has detrimental consequences to spermatocyte development, myelination, axonal survival, eye development, and long-term survival, though the precise reasons remain elusive. Lipids containing alkyl- and vinyl-linked fatty alcohols are development-specific products inM. xanthus. Here, we show that one of them rescues the development of E signal-producing mutants at physiological concentrations.

scholarly journals Staphylococcus aureus Fatty Acid Auxotrophs Do Not Proliferate in Mice

2013 ◽  
Vol 57 (11) ◽  
pp. 5729-5732 ◽  
Author(s):  
Joshua B. Parsons ◽  
Matthew W. Frank ◽  
Jason W. Rosch ◽  
Charles O. Rock
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Normal Growth ◽  
Acid Synthesis ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Content Type

ABSTRACTInactivation of acetyl-coenzyme A (acetyl-CoA) carboxylase confers resistance to fatty acid synthesis inhibitors inStaphylococcus aureuson media supplemented with fatty acids. The addition ofanteiso-fatty acids (1 mM) plus lipoic acid supports normal growth of ΔaccDstrains, but supplementation with mammalian fatty acids was less efficient. Mice infected with strain RN6930 developed bacteremia, but bacteria were not detected in mice infected with its ΔaccDderivative.S. aureusbacteria lacking acetyl-CoA carboxylase can be propagatedin vitrobut were unable to proliferate in mice, suggesting that the acquisition of inactivating mutations in this enzyme is not a mechanism for the evasion of fatty acid synthesis inhibitors.

scholarly journals Quantitative Trait Loci and Candidate Genes Associated with Fatty Acid Content of Watermelon Seed

2014 ◽  
Vol 139 (4) ◽  
pp. 433-441 ◽  
Author(s):  
Geoffrey Meru ◽  
Cecilia McGregor
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Palmitic Acid ◽  
Acid Composition ◽  
Seed Oil ◽  
Unsaturated Fatty Acids ◽  
Watermelon Seed

Seed oil percentage (SOP) and fatty acid composition of watermelon (Citrullus lanatus) seeds are important traits in Africa, the Middle East, and Asia where the seeds provide a significant source of nutrition and income. Oil yield from watermelon seed exceeds 50% (w/w) and is high in unsaturated fatty acids, a profile comparable to that of sunflower (Helianthus annuus) and soybean (Glycine max) oil. As a result of novel non-food uses of plant-derived oils, there is an increasing need for more sources of vegetable oil. To improve the nutritive value of watermelon seed and position watermelon as a potential oil crop, it is critical to understand the genetic factors associated with SOP and fatty acid composition. Although the fatty acid composition of watermelon seed is well documented, the underlying genetic basis has not yet been studied. Therefore, the current study aimed to elucidate the quality of watermelon seed oil and identify genomic regions and candidate genes associated with fatty acid composition. Seed from an F2 population developed from a cross between an egusi type (PI 560023), known for its high SOP, and Strain II (PI 279261) was phenotyped for palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), and linoleic acid (18:2). Significant (P < 0.05) correlations were found between palmitic and oleic acid (0.24), palmitic and linoleic acid (–0.37), stearic and linoleic acid (–0.21), and oleic and linoleic acid (–0.92). A total of eight quantitative trait loci (QTL) were associated with fatty acid composition with a QTL for oleic and linoleic acid colocalizing on chromosome (Chr) 6. Eighty genes involved in fatty biosynthesis including those modulating the ratio of saturated and unsaturated fatty acids were identified from the functionally annotated genes on the watermelon draft genome. Several fatty acid biosynthesis genes were found within and in close proximity to the QTL identified in this study. A gene (Cla013264) homolog to fatty acid elongase (FAE) was found within the 1.5-likelihood-odds (LOD) interval of the QTL for palmitic acid (R2 = 7.6%) on Chr 2, whereas Cla008157, a homolog to omega-3-fatty acid desaturase and Cla008263, a homolog to FAE, were identified within the 1.5-LOD interval of the QTL for palmitic acid (R2 = 24.7%) on Chr 3. In addition, the QTL for palmitic acid on Chr 3 was located ≈0.60 Mbp from Cla002633, a gene homolog to fatty acyl- [acyl carrier protein (ACP)] thioesterase B. A gene (Cla009335) homolog to ACP was found within the flanking markers of the QTL for oleic acid (R2 = 17.9%) and linoleic acid (R2 = 21.5%) on Chr 6, whereas Cla010780, a gene homolog to acyl-ACP desaturase was located within the QTL for stearic acid (R2 = 10.2%) on Chr 7. On Chr 8, another gene (Cla013862) homolog to acyl-ACP desaturase was found within the 1.5-LOD interval of the QTL for oleic acid (R2 = 13.5%). The genes identified in this study are possible candidates for the development of functional markers for application in marker-assisted selection for fatty acid composition in watermelon seed. To the best of our knowledge, this is the first study that aimed to elucidate genetic control of the fatty acid composition of watermelon seed.

scholarly journals Oleate Hydratase (OhyA) Is a Virulence Determinant in Staphylococcus aureus

2021 ◽  
Author(s):  
Christopher D. Radka ◽  
Justin L. Batte ◽  
Matthew W. Frank ◽  
Jason W. Rosch ◽  
Charles O. Rock
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Unsaturated Fatty Acids ◽  
Commensal Bacteria ◽  
Hydroxy Fatty Acids ◽  
Infection Model ◽  
Infection Site ◽  
Human Pathogen ◽  
Content Type ◽  
Oleate Hydratase

The oleate hydratase protein family was discovered in commensal bacteria that utilize host unsaturated fatty acids as the substrates to produce a spectrum of hydroxylated products. These hydroxy fatty acids are thought to act as signaling molecules that suppress the inflammatory response to create a more tolerant environment for the microbiome. S. aureus is a significant human pathogen, and defining the mechanisms used to evade the immune response is critical to understanding pathogenesis. S. aureus expresses an OhyA that produces at least three 10-hydroxy fatty acids from host unsaturated fatty acids at the infection site, and an S. aureus strain lacking the ohyA gene has compromised virulence in an immunocompetent infection model.

Sign in / Sign up

Export Citation Format

Share Document