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.

scholarly journals Branched chain fatty acid synthesis drives tissue-specific innate immune response and  infection dynamics of  Staphylococcus aureus

2021 ◽  
Vol 17 (9) ◽  
pp. e1009930
Author(s):  
Xi Chen ◽  
Wei Ping Teoh ◽  
Madison R. Stock ◽  
Zachary J. Resko ◽  
Francis Alonzo
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Fatty Acid ◽  
Membrane Fluidity ◽  
Unsaturated Fatty Acids ◽  
Cell Envelope ◽  
Acyl Chain ◽  
Dependent Manner ◽  
Infection Dynamics ◽  
Branched Chain

Fatty acid-derived acyl chains of phospholipids and lipoproteins are central to bacterial membrane fluidity and lipoprotein function. Though it can incorporate exogenous unsaturated fatty acids (UFA), Staphylococcus aureus synthesizes branched chain fatty acids (BCFA), not UFA, to modulate or increase membrane fluidity. However, both endogenous BCFA and exogenous UFA can be attached to bacterial lipoproteins. Furthermore, S. aureus membrane lipid content varies based upon the amount of exogenous lipid in the environment. Thus far, the relevance of acyl chain diversity within the S. aureus cell envelope is limited to the observation that attachment of UFA to lipoproteins enhances cytokine secretion by cell lines in a TLR2-dependent manner. Here, we leveraged a BCFA auxotroph of S. aureus and determined that driving UFA incorporation disrupted infection dynamics and increased cytokine production in the liver during systemic infection of mice. In contrast, infection of TLR2-deficient mice restored inflammatory cytokines and bacterial burden to wildtype levels, linking the shift in acyl chain composition toward UFA to detrimental immune activation in vivo. In in vitro studies, bacterial lipoproteins isolated from UFA-supplemented cultures were resistant to lipase-mediated ester hydrolysis and exhibited heightened TLR2-dependent innate cell activation, whereas lipoproteins with BCFA esters were completely inactivated after lipase treatment. These results suggest that de novo synthesis of BCFA reduces lipoprotein-mediated TLR2 activation and improves lipase-mediated hydrolysis making it an important determinant of innate immunity. Overall, this study highlights the potential relevance of cell envelope acyl chain repertoire in infection dynamics of bacterial pathogens.

Effects of exogenous fatty acids on growth and enterotoxin B formation by Staphylococcus aureus 14458 and its membrane mutant

1977 ◽  
Vol 23 (4) ◽  
pp. 389-397 ◽  
Author(s):  
Robert A. Altenbern
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Fatty Acid ◽  
Saturated Fatty Acid ◽  
Unsaturated Fatty Acid ◽  
Fatty Acid Mixture ◽  
Acid Mixture ◽  
Membrane Phospholipids ◽  
Enterotoxin B ◽  
Fatty Acid Mixtures

Growth and enterotoxin B (SEB) formation by Staphylococcus aureus 14458 and its membrane mutant can be depressed or stimulated by addition of graded amounts of saturated or unsaturated fatty acid mixtures. Under some conditions depression of SEB formation is separable from growth inhibition. Individual fatty acids most active in altering growth and (or) SEB production have been identified. Small amounts of unsaturated fatty acid mixture not only antagonize some effects of saturated fatty acid mixtures, but also appear to potentiate inhibition of growth and SEB formation by the saturated fatty acid mixture. 2-Adamantanone, a compound which increases cell membrane fluidity, strongly suppresses SEB formation while stimulating growth. The results are discussed in relation to possible effects of exogenous fatty acids on the composition of membrane phospholipids and attendant changes in SEB production.

scholarly journals Factors Influencing the Production of Different Types of Fatty Acid and Staphyloxanthin in the Staphylococcus aureus Membrane

2018 ◽  
Author(s):  
Kiran Tiwari ◽  
Craig Gatto ◽  
Brian J. Wilkinson
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Fatty Acid ◽  
Membrane Fluidity ◽  
Metabolic Regulation ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Biosynthesis ◽  
Carotenoid Biosynthesis ◽  
Straight Chain ◽  
Chain Fatty Acids

Fatty acids play a major role in determining membrane biophysical properties. Staphylococcus aureus produces branched-chain fatty acids (BCFAs) and straight-chain fatty acids (SCFAs), and can incorporate exogenous SCFAs and straight-chain unsaturated fatty acids (SCUFAs). Many S. aureus strains produce the triterpenoid pigment staphyloxanthin, and the balance of BCFAs, SCFAs 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 condition indicating that staphyloxanthin does not influence fatty acid composition. Strain Pig1 had decreased membrane fluidity as measured by fluorescence anisotropy than 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 SCFA 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.

scholarly journals DesT Coordinates the Expression of Anaerobic and Aerobic Pathways for Unsaturated Fatty Acid Biosynthesis in Pseudomonas aeruginosa

2009 ◽  
Vol 192 (1) ◽  
pp. 280-285 ◽  
Author(s):  
Chitra Subramanian ◽  
Charles O. Rock ◽  
Yong-Mei Zhang
Keyword(s):  
Fatty Acids ◽  
Pseudomonas Aeruginosa ◽  
Fatty Acid ◽  
Dna Sequences ◽  
Unsaturated Fatty Acid ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Biosynthesis ◽  
Acid Synthesis ◽  
Cell Extracts ◽  
Translational Start

ABSTRACT The fabA and fabB genes are responsible for anaerobic unsaturated fatty acid formation in Pseudomonas aeruginosa. Expression of the fabAB operon was repressed by exogenous unsaturated fatty acids, and DNA sequences upstream of the translational start site were used to affinity purify DesT. The single protein interaction with the fabAB promoter detected in wild-type cell extracts was absent in the desT deletion strain, as was the repression of fabAB expression by unsaturated fatty acids. Thus, DesT senses the overall composition of the acyl-coenzyme A pool to coordinate the expression of the operons for the anaerobic (fabAB) and aerobic (desCB) pathways for unsaturated fatty acid synthesis.

scholarly journals The biochemical content and antioxidant capacities of endemic Tanacetum densum (Lab.) Schultz Bip. subsp. laxum, and Tanacetum densum (Lab.) Schultz Bip. subsp. amani Heywood growing in Turkey

2021 ◽  
Vol 81 (4) ◽  
pp. 1106-1114
Author(s):  
İ. Emre
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Unsaturated Fatty Acid ◽  
Acid Content ◽  
Unsaturated Fatty Acids ◽  
Phenolic Content ◽  
Total Phenolics ◽  
Fatty Acid Content ◽  
Radical Scavenging ◽  
Unsaturated Fatty Acid Content

Abstract Medicinal plants have a significant role in preventing and curing several diseases, and Tanacetum L. is one of these plants. The aim of the present study is to determine the fatty acid, lipid-soluble vitamin, sterol, phenolic content, and antioxidant capacity of Tanacetum densum subsp. laxum and Tanacetum densum subsp. amani, to compare the effect of altitude on the biochemical content and to compare systematically by using fatty acids and phenolics. This study showed that palmitic acid (C16:0) and stearic acid (C18:0) are major sources of saturated fatty acid and oleic acid (C18:1 n9), and linoleic acid (18:2 n6c) and a-linolenic acid (C18:3 n3) are the principal unsaturated fatty acids in the two endemic Tanacetum densum taxa. Also, this study found that the unsaturated fatty acid content (60.11±1.61%) of Tanacetum densum subsp. laxum was higher than the unsaturated fatty acid content (44.13±1.28%) of Tanacetum densum subsp. amani. And also, the ω6/ω3 ratio of Tanacetum densum subsp. laxum (1.74) and Tanacetum densum subsp. amani (1.60) was found to be similar. However, this study determined that the lipid soluble vitamin and sterol content of two endemic Tanacetum taxa are low except for stigmasterol. Present study showed that catechin is principal phenolic in the Tanacetum densum taxa. This study also found that Tanacetum densum subsp. laxum and Tanacetum densum subsp. amani had the highest levels of catechin, vanillic acid, and caffeic acid content though the phenolic amounts, particularly catechin and quercetin, were dissimilar in the T. densum taxa. This study suggested that ecological conditions such as altitude may affect the biochemical content of two endemic Tanacetum densum taxa. Furthermore, the current study determined that two endemic Tanacetum L. taxa had potent radical scavenging capacities and found a correlation between total phenolics and antioxidant activity.

scholarly journals Structure and mechanism of Staphylococcus aureus oleate hydratase (OhyA)

2020 ◽  
pp. jbc.RA120.016818
Author(s):  
Christopher D. Radka ◽  
Justin L. Batte ◽  
Matthew W. Frank ◽  
Brandon M. Young ◽  
Charles O. Rock
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Fatty Acid ◽  
Active Site ◽  
Catalytic Mechanism ◽  
Unsaturated Fatty Acids ◽  
Binary And Ternary Complexes ◽  
Hydronium Ion ◽  
Multiple Structures ◽  
Fad Binding

FAD-dependent bacterial oleate hydratases (OhyA) catalyze the addition of water to isolated fatty acid carbon-carbon double bonds.  Staphylococcus aureus uses OhyA to counteract the host innate immune response by inactivating antimicrobial unsaturated fatty acids.  Mechanistic information explaining how OhyAs catalyze regio- and stereospecific hydration is required to understand their biological functions and the potential for engineering new products.  In this study, we deduced the catalytic mechanism of OhyA from multiple structures of S. aureus OhyA in binary and ternary complexes with combinations of ligands along with biochemical analyses of relevant mutants.  The substrate-free state shows Arg81 is the gatekeeper that controls fatty acid entrance to the active site.  FAD binding engages the catalytic loop to simultaneously rotate Glu82 into its active conformation and Arg81 out of the hydrophobic substrate tunnel, allowing the fatty acid to rotate into the active site.  FAD binding also dehydrates the active site, leaving a single water molecule connected to Glu82.  This active site water is a hydronium ion based on the analysis of its hydrogen bond network in the OhyA•PEG400•FAD complex. We conclude that OhyA accelerates acid-catalyzed alkene hydration by positioning the fatty acid double bond to attack the active site hydronium ion, followed by the addition of water to the transient carbocation intermediate.  Structural transitions within S. aureus OhyA channel oleate to the active site, curl oleate around the substrate water, and stabilize the hydroxylated product to inactivate antimicrobial fatty acids.

scholarly journals The effects of unsaturated fatty acid depletion on the proton permeability and energetic functions of yeast mitochondria

1977 ◽  
Vol 166 (3) ◽  
pp. 565-570 ◽  
Author(s):  
J. M. Haslam ◽  
Norman F. Fellows
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Unsaturated Fatty Acid ◽  
Acid Content ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Content ◽  
Energy Charge ◽  
Tween 80 ◽  
Adenylate Energy Charge ◽  
Proton Permeability

1. The fatty acid composition of the ole-1 and ole-1 petite mutants of Saccharomyces cerevisiae was manipulated by growing the organism in the presence of defined supplements of Tween 80 or by allowing cells that had first been grown in the presence of Tween 80 to deplete their unsaturated fatty acids by sequent growth in the absence of Tween 80. 2. The transition temperature of Arrhenius plots of mitochondrial ATPase (adenosine triphosphatase) increases as the unsaturated fatty acid content is lowered. 3. Cells require larger amounts of unsaturated fatty acids to grow on ethanol at lower temperatures. 4. Cells that stop growing owing to unsaturated fatty acid depletion at low temperatures are induced to grow further by raising the temperature and this results in a further depletion of unsaturated acids. This is due to a higher rate, but not a greater efficiency, of mitochondrial ATP synthesis. 5. Arrhenius plots of the passive permeability of mitochondria to protons between 4 and 37°C are linear. The rate and the Arrhenius activation energy of proton entry increase greatly as the unsaturated fatty acid content is lowered. 6. Unsaturated fatty acid depletion has the same effects on the proton permeability of ole-1 petite mitochondria, indicating that the mitochondrially synthesized subunits of the ATPase are not involved in the enhanced rates of proton entry. 7. The adenylate energy charge of depleted ole-1 cells is greatly decreased by growth on ethanol medium. 8. The adenylate energy charge of isolated mitochondria is also lowered by unsaturated fatty acid depletion. 9. The results confirm that unsaturated fatty acid depletion uncouples oxidative phosphorylation in yeast both in vivo and in vitro, and is a consequence of changes in the lipid part of the membrane.

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