scholarly journals Biochemical studies on cell fusion. II. Control of fusion response by lipid alteration.

1985 ◽  
Vol 101 (4) ◽  
pp. 1591-1598 ◽  
Author(s):  
D S Roos ◽  
P W Choppin
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Membrane Fluidity ◽  
Cell Fusion ◽  
Cell Lines ◽  
Lipid Composition ◽  
Unsaturated Fatty Acids ◽  
Acyl Chain ◽  
Trans Unsaturated Fatty Acids ◽  
Fusion Response

The preceding communication (Roos, D.S. and P.W. Choppin, 1985, J. Cell Biol. 101:1578-1590) described the lipid composition of a series of mouse fibroblast cell lines which vary in susceptibility to the fusogenic effects of polyethylene glycol (PEG). Two alterations in lipid content were found to be directly correlated with resistance to PEG-induced cell fusion: increases in fatty acyl chain saturation, and the elevation of neutral glycerides, including an unusual ether-linked compound. In this study, we have probed the association between lipid composition and cell fusion through the use of fatty acid supplements to the cellular growth medium, and show that the fusibility of cells can be controlled by altering their acyl chain composition. The parental Clone 1D cells contain moderately unsaturated fatty acids with a ratio of saturates to polyunsaturates (S/P) approximately 1 and fuse virtually to completion following a standard PEG treatment. By contrast, the lipids of a highly fusion-resistant mutant cell line, F40, are highly saturated (S/P approximately 4). When the S/P ratio of Clone 1D cells was increased to approximate that normally found in F40 cells by growth in the presence of high concentrations of saturated fatty acids, they became highly resistant to PEG. Reduction of the S/P ratio of F40 cells by growth in cis-polyunsaturated fatty acids rendered them susceptible to fusion. Cell lines F8, F16, etc., which are normally intermediate between Clone 1D and F40 in both lipid composition and fusion response, can be altered in either direction (towards either increased or decreased susceptibility to fusion) by the addition of appropriate fatty acids to the growth medium. Although trans-unsaturated fatty acids have phase-transition temperatures roughly similar to saturated compounds, and might therefore be expected to affect membrane fluidity in a similar manner, trans-unsaturated fatty acids exerted the same effect as cis-unsaturates on the control of PEG-induced cell fusion. This observation suggests that the control of cell fusion by alteration of fatty acid content is not due to changes in membrane fluidity, and thus that the fatty acids are involved in some other way in the modulation of cell fusion.

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.

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 Identification, Evolution, Expression, and Docking Studies of Fatty Acid Desaturase Genes in Wheat (Triticum aestivum L.)

2020 ◽  
Author(s):  
Zahra Hajiahmadi ◽  
Amin Abedi ◽  
Hui Wei ◽  
Weibo Sun ◽  
Honghua Ruan ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Plant Development ◽  
Unsaturated Fatty Acids ◽  
Edible Oils ◽  
Close Contact ◽  
Acyl Chain ◽  
Environmental Stresses ◽  
Site Directed Mutagenesis ◽  
A Genome

Abstract Backgrounds: Fatty acid desaturases (FADs) introduce a double bond into the fatty acids acyl chain resulting in unsaturated fatty acids that have essential roles in plant development and response to biotic and abiotic stresses. Wheat germ oil, one of the important by-products of wheat, can be a good alternative for edible oils with clinical advantages due to the high amount of unsaturated fatty acids. Therefore, we performed a genome-wide analysis of the wheat FAD gene family (TaFADs).Results: 68 FAD genes were identified from the wheat genome. Based on the phylogenetic analysis, wheat FADs clustered into five subfamilies, including FAB2, FAD2/FAD6, FAD4, DES/SLD, and FAD3/FAD7/FAD8. The TaFADs were distributed on chromosomes 2A-7B with 0 to 10 introns. The Ka/Ks ratio was less than one for most of the duplicated pair genes revealed that the function of the genes had been maintained during the evolution. Several cis-acting elements related to hormones and stresses in the TaFADs promoters indicated the role of these genes in plant development and responses to environmental stresses. Likewise, 72 SSRs and 91 miRNAs in 36 and 47 TaFADs have been identified. According to RNA-seq data analysis, the highest expression in all developmental stages and tissues was related to TaFAB2.5, TaFAB2.12, TaFAB2.15, TaFAB2.17, TaFAB2.20, TaFAD2.1, TaFAD2.6, and TaFAD2.8 genes while the highest expression in response to temperature stress was related to TaFAD2.6, TaFAD2.8, TaFAB2.15, TaFAB2.17, and TaFAB2.20. Furthermore, docking simulations revealed several residues in the active site of TaFAD2.6 and TaFAD2.8 in close contact with the docked oleic acid that could be useful in future site-directed mutagenesis studies to increase the catalytic efficiency of them and subsequently improve agronomic quality and tolerance of wheat against environmental stresses. Conclusions: This study provides comprehensive information that can lead to the detection of candidate genes for wheat genetic modification.

scholarly journals Identification, evolution, expression, and docking studies of fatty acid desaturase genes in wheat (Triticum aestivum L.)

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Zahra Hajiahmadi ◽  
Amin Abedi ◽  
Hui Wei ◽  
Weibo Sun ◽  
Honghua Ruan ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Plant Development ◽  
Unsaturated Fatty Acids ◽  
Edible Oils ◽  
Close Contact ◽  
Acyl Chain ◽  
Environmental Stresses ◽  
Site Directed Mutagenesis ◽  
A Genome

Abstract Backgrounds Fatty acid desaturases (FADs) introduce a double bond into the fatty acids acyl chain resulting in unsaturated fatty acids that have essential roles in plant development and response to biotic and abiotic stresses. Wheat germ oil, one of the important by-products of wheat, can be a good alternative for edible oils with clinical advantages due to the high amount of unsaturated fatty acids. Therefore, we performed a genome-wide analysis of the wheat FAD gene family (TaFADs). Results 68 FAD genes were identified from the wheat genome. Based on the phylogenetic analysis, wheat FADs clustered into five subfamilies, including FAB2, FAD2/FAD6, FAD4, DES/SLD, and FAD3/FAD7/FAD8. The TaFADs were distributed on chromosomes 2A-7B with 0 to 10 introns. The Ka/Ks ratio was less than one for most of the duplicated pair genes revealed that the function of the genes had been maintained during the evolution. Several cis-acting elements related to hormones and stresses in the TaFADs promoters indicated the role of these genes in plant development and responses to environmental stresses. Likewise, 72 SSRs and 91 miRNAs in 36 and 47 TaFADs have been identified. According to RNA-seq data analysis, the highest expression in all developmental stages and tissues was related to TaFAB2.5, TaFAB2.12, TaFAB2.15, TaFAB2.17, TaFAB2.20, TaFAD2.1, TaFAD2.6, and TaFAD2.8 genes while the highest expression in response to temperature stress was related to TaFAD2.6, TaFAD2.8, TaFAB2.15, TaFAB2.17, and TaFAB2.20. Furthermore, docking simulations revealed several residues in the active site of TaFAD2.6 and TaFAD2.8 in close contact with the docked oleic acid that could be useful in future site-directed mutagenesis studies to increase the catalytic efficiency of them and subsequently improve agronomic quality and tolerance of wheat against environmental stresses. Conclusions This study provides comprehensive information that can lead to the detection of candidate genes for wheat genetic modification.

scholarly journals Impaired fetal erythrocytes' filterability: relationship with cell size, membrane fluidity, and membrane lipid composition

Blood ◽  
1992 ◽  
Vol 79 (8) ◽  
pp. 2148-2153 ◽  
Author(s):  
FC Colin ◽  
Y Gallois ◽  
D Rapin ◽  
A Meskar ◽  
JJ Chabaud ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Membrane Fluidity ◽  
Lipid Composition ◽  
Fluorescence Polarization ◽  
High Performance ◽  
Unsaturated Fatty Acids ◽  
Membrane Lipid ◽  
Gas Liquid Chromatography ◽  
Biophysical Parameters ◽  
Membrane Lipid Composition

Abstract The lipid composition of erythrocytes (red blood cells [RBCs]) plays a significant role in determining certain membrane biophysical properties. We have found that fetal RBCs showed a dramatically low filterability compared with adult RBCs and questioned whether this could be a consequence of their membrane lipid composition. We therefore studied fetal RBCs at two different gestational ages, neonatal RBCs and adult RBCs. Biophysical parameters were studied using two different techniques, filterability and membrane fluidity. The latter was measured by fluorescence polarization using three different probes. The membrane lipid composition was examined by measuring cholesterol and phospholipids. After extraction of the phospholipids, followed by high performance thin-layer chromatography, the fatty acids in the phospholipid subfractions were analyzed by gas-liquid chromatography. The fetal RBCs' filterability was found to be correlated with both the larger size and the higher hemoglobin content of the cells, but there was no correlation between RBC filterability and fluidity or membrane lipid composition. In adult RBCs, compared with neonatal RBCs, the slight increase of unsaturated fatty acids in phosphatidylcholine and phosphatidylethanolamine should have increased the membrane fluidity. However, in RBCs, no change was observed in the fluidity parameters measured by fluorescence polarization.

scholarly journals Impaired fetal erythrocytes' filterability: relationship with cell size, membrane fluidity, and membrane lipid composition

Blood ◽  
1992 ◽  
Vol 79 (8) ◽  
pp. 2148-2153
Author(s):  
FC Colin ◽  
Y Gallois ◽  
D Rapin ◽  
A Meskar ◽  
JJ Chabaud ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Membrane Fluidity ◽  
Lipid Composition ◽  
Fluorescence Polarization ◽  
High Performance ◽  
Unsaturated Fatty Acids ◽  
Membrane Lipid ◽  
Gas Liquid Chromatography ◽  
Biophysical Parameters ◽  
Membrane Lipid Composition

The lipid composition of erythrocytes (red blood cells [RBCs]) plays a significant role in determining certain membrane biophysical properties. We have found that fetal RBCs showed a dramatically low filterability compared with adult RBCs and questioned whether this could be a consequence of their membrane lipid composition. We therefore studied fetal RBCs at two different gestational ages, neonatal RBCs and adult RBCs. Biophysical parameters were studied using two different techniques, filterability and membrane fluidity. The latter was measured by fluorescence polarization using three different probes. The membrane lipid composition was examined by measuring cholesterol and phospholipids. After extraction of the phospholipids, followed by high performance thin-layer chromatography, the fatty acids in the phospholipid subfractions were analyzed by gas-liquid chromatography. The fetal RBCs' filterability was found to be correlated with both the larger size and the higher hemoglobin content of the cells, but there was no correlation between RBC filterability and fluidity or membrane lipid composition. In adult RBCs, compared with neonatal RBCs, the slight increase of unsaturated fatty acids in phosphatidylcholine and phosphatidylethanolamine should have increased the membrane fluidity. However, in RBCs, no change was observed in the fluidity parameters measured by fluorescence polarization.

scholarly journals Identification, Evolution, Expression, and Docking Studies of Fatty Acid Desaturase Genes in Wheat (Triticum aestivum L.)

2020 ◽  
Author(s):  
Zahra Hajiahmadi ◽  
Amin Abedi ◽  
Hui Wei ◽  
Weibo Sun ◽  
Honghua Ruan ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Plant Development ◽  
Unsaturated Fatty Acids ◽  
Edible Oils ◽  
Close Contact ◽  
Acyl Chain ◽  
Environmental Stresses ◽  
Site Directed Mutagenesis ◽  
A Genome

Abstract Backgrounds: Fatty acid desaturases (FADs) introduce a double bond into the fatty acids acyl chain resulting in unsaturated fatty acids that have essential roles in plant development and response to biotic and abiotic stresses. Wheat germ oil, one of the important by-products of wheat, can be a good alternative for edible oils with clinical advantages due to the high amount of unsaturated fatty acids. Therefore, we performed a genome-wide analysis of the wheat FAD gene family (TaFADs).Results: 68 FAD genes were identified from the wheat genome. Based on the phylogenetic analysis, wheat FADs clustered into five subfamilies, including FAB2, FAD2/FAD6, FAD4, DES/SLD, and FAD3/FAD7/FAD8. The TaFADs were distributed on chromosomes 2A-7B with 0 to 10 introns. The Ka/Ks ratio was less than one for most of the duplicated pair genes revealed that the function of the genes had been maintained during the evolution. Several cis-acting elements related to hormones and stresses in the TaFADs promoters indicated the role of these genes in plant development and responses to environmental stresses. Likewise, 72 SSRs and 91 miRNAs in 36 and 47 TaFADs have been identified. According to RNA-seq data analysis, the highest expression in all developmental stages and tissues was related to TaFAB2.5, TaFAB2.12, TaFAB2.15, TaFAB2.17, TaFAB2.20, TaFAD2.1, TaFAD2.6, and TaFAD2.8 genes while the highest expression in response to temperature stress was related to TaFAD2.6, TaFAD2.8, TaFAB2.15, TaFAB2.17, and TaFAB2.20. Furthermore, docking simulations revealed several residues in the active site of TaFAD2.6 and TaFAD2.8 in close contact with the docked oleic acid that could be useful in future site-directed mutagenesis studies to increase the catalytic efficiency of them and subsequently improve agronomic quality and tolerance of wheat against environmental stresses. Conclusions: This study provides comprehensive information that can lead to the detection of candidate genes for wheat genetic modification.

scholarly journals Growth-Environment Dependent Modulation ofStaphylococcus aureusBranched-Chain to Straight-Chain Fatty Acid Ratio and Incorporation of Unsaturated Fatty Acids

2016 ◽  
Author(s):  
Suranjana Sen ◽  
Seth R. Johnson ◽  
Yang Song ◽  
Sirisha Sirobhushanam ◽  
Ryan Tefft ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Membrane Fluidity ◽  
Acid Composition ◽  
Unsaturated Fatty Acids ◽  
Cell Physiology ◽  
Biophysical Properties ◽  
Straight Chain ◽  
Chain Fatty Acids

AbstractThe fatty acid composition of membrane glycerolipids is a major determinant ofStaphylococcus aureusmembrane biophysical properties that impacts key factors in cell physiology including susceptibility to membrane active antimicrobials, pathogenesis, and response to environmental stress. The fatty acids ofS. aureusare considered to be a mixture of branched-chain fatty acids (BCFAs), which increase membrane fluidity, and straight-chain fatty acids (SCFAs) that decrease it. The balance of BCFAs and SCFAs in strains USA300 and SH1000 was affected considerably by differences in the conventional laboratory medium in which the strains were grown with media such as Mueller-Hinton broth and Luria broth resulting in high BCFAs and low SCFAs, whereas growth in Tryptic Soy Broth and Brain-Heart Infusion broth led to reduction in BCFAs and an increase in SCFAs. Straight-chain unsaturated fatty acids (SCUFAs) were not detected. However, when the organism was grownex vivoin serum, the fatty acid composition was radically different with SCUFAs, which increase membrane fluidity, making up a substantial proportion of the total (<25%) with SCFAs (>37%) and BCFAs (>36%) making up the rest. Staphyloxanthin, an additional major membrane lipid component unique toS. aureus, tended to be greater in content in cells with high BCFAs or SCUFAs. Cells with high staphyloxanthin content had a lower membrane fluidity that was attributed to increased production of staphyloxanthin.S. aureussaves energy and carbon by utilizing host fatty acids for part of its total fatty acids when growing in serum. The fatty acid composition ofin vitrogrownS. aureusis likely to be a poor reflection of the fatty acid composition and biophysical properties of the membrane when the organism is growing in an infection in view of the role of SCUFAs in staphylococcal membrane composition and virulence.Funding:This work was funded in part by grant 1R15AI099977 to Brian Wilkinson and Craig Gatto and grant 1R15GM61583 to Craig Gatto from the National Institutes of Health

scholarly journals Identification, Evolution, Expression, and Docking Studies of Fatty Acid Desaturase Genes in Wheat (Triticum aestivum L.)

2020 ◽  
Author(s):  
Zahra Hajiahmadi ◽  
Amin Abedi ◽  
Hui Wei ◽  
Weibo Sun ◽  
Honghua Ruan ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Plant Development ◽  
Unsaturated Fatty Acids ◽  
Edible Oils ◽  
Close Contact ◽  
Acyl Chain ◽  
Environmental Stresses ◽  
Site Directed Mutagenesis ◽  
Wheat Germ Oil

Abstract Backgrounds: Fatty acid desaturases (FADs) introduce a double bond into the fatty acids acyl chain resulting in unsaturated fatty acids which have important roles in plant development and response to biotic and abiotic stresses. Wheat germ oil, one of the important by-products of wheat, can be a good alternative for edible oils with clinical advantages due to the high amount of unsaturated fatty acids. Therefore, genome-wide analysis of wheat FAD gene family (TaFADs) has been performed.Results: 68 FAD genes were identified from the wheat genome. Based on the phylogenetic analysis, wheat FADs clustered into five subfamilies, including FAB2, FAD2/FAD6, FAD4, DES/SLD, and FAD3/FAD7/FAD8. The TaFADs were distributed on chromosomes 2A-7B with 0 to 10 introns. The Ka/Ks ratio was less than one for most of the duplicated pair genes revealed that the function of the genes has been maintained during the evolution. Several cis-acting elements related to hormones and stresses in the TaFADs promoters indicated the role of these genes in plant development and responses to environmental stresses. Likewise, 72 SSRs and 91 miRNAs in 36 and 47 TaFADs have been identified. According to RNA-seq data analysis, the highest expression in all developmental stages and tissues was related to TaFAB2.5, TaFAB2.12, TaFAB2.15, TaFAB2.17, TaFAB2.20, TaFAD2.1, TaFAD2.6, and TaFAD2.8 genes while the highest expression in response to temperature stress was related to TaFAD2.6, TaFAD2.8, TaFAB2.15, TaFAB2.17, and TaFAB2.20. Furthermore, docking simulations revealed several residues in the active site of TaFAD2.6 and TaFAD2.8 in close contact with the docked oleic acid that could be useful in future site-directed mutagenesis studies to increase the catalytic efficiency of them and subsequently improve agronomic quality and tolerance of wheat against environmental stresses. Conclusions:This study provides comprehensive information that can lead to the detection of candidate genes for wheat genetic modification.

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 (Pig1&Delta;crtM) 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.

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