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Langmuir : the ACS Journal of Surfaces... Sep 2018Synchrotron-based X-ray scattering measurements of phase-separated surfactant monolayers at the air-water interface provide molecular-level structural information about...
Synchrotron-based X-ray scattering measurements of phase-separated surfactant monolayers at the air-water interface provide molecular-level structural information about the packing and ordering of film components. In this work, grazing incidence X-ray diffraction (GIXD) and X-ray reflectivity (XR) measurements were used to collect crystallographic structural information for binary mixed monolayers of arachidic acid (AA, CHCOOH) with perfluorotetradecanoic acid (PA, CFCOOH), a system that has previously been investigated using a variety of thermodynamic and micron-scale structural characterization methods. GIXD measurements at surface pressures of π = 5, 15, and 30 mN/m indicated that AA in pure and mixed films forms a rectangular lattice at π = 5 and 15 mN/m but a hexagonal lattice at π = 30 mN/m. PA formed hexagonal lattices under all conditions, with films being highly ordered and crystalline (as determined by Bragg peak width) at even the lowest surface pressures investigated. Phase separation occurred for all mixed monolayer film compositions and surface pressures, manifesting as diffraction peaks characteristic of the individual components appearing at different in-plane scattering vector q. For both pure and mixed films, the molecular tilt angle of the AA hydrocarbon chain toward the nearest-neighbor was substantial at low pressures but decreased with increasing pressure. The PA fluorocarbon chain showed negligible molecular tilt under all conditions, and was oriented normal to the subphase surface regardless of surface pressure or the presence of AA in the films. In all cases, the two components in the mixed film behaved entirely independently of film composition, which is exactly the expected result for a fully phase-separated, immiscible system. XR measurements of film thickness at the air-water interface supported these results; overall film thickness approached the calculated ideal surfactant tail lengths with increasing surface pressure, indicating nearly normal oriented surfactants. The overall surfactant packing and crystallographic features of the mixed monolayers are discussed in terms of the lipophobic nature of the perfluorinated surfactant as well as in context of thermodynamic miscibility and domain structure formation reported elsewhere in the literature for these mixed monolayer systems.
PubMed: 30102043
DOI: 10.1021/acs.langmuir.8b02291 -
Langmuir : the ACS Journal of Surfaces... Mar 2019The influence of the copper(II) ion on the formation, morphology, and organization of an arachidic acid monolayer was investigated using Langmuir-Blodgett (LB)...
The influence of the copper(II) ion on the formation, morphology, and organization of an arachidic acid monolayer was investigated using Langmuir-Blodgett (LB) monolayers, Π-A isotherms, and Brewster angle microscopy (BAM). Our findings indicate that a Cu-complexed LB film exhibits an order that depends on the subphase pH, analogous to other metal ions. Yazdanian , M. ; et al. Ionic Interactions of Fatty Acid Monolayers at the Air-Water Interface . Langmuir 1990 , 6 , 1093 - 1098 . Kurnaz , M. L. ; et al. Morphology of Microphase Separation in Arachidic Acid-Cadmium Arachidate Langmuir-Blodgett Multilayers . J. Phys. Chem. 1996 , 100 , 11113 - 11119 . The metal ion facilitates the formation of solid-phase films at surface pressures as low as 5 mN/m. The films exhibit a rigid, ordered phase, evidenced by the absence of a collapse point and an increase in surface pressure rather than the typical sharp decrease in surface pressure, indicative of film failure. Amphiphile ionic charge vs pH (i.e., the extent of arachidic acid protonation) plays a role in the observed absence of collapse and the ability of the films to maintain order and cohesion at high surface pressures (ca. 65 mN/m). Additionally, film thickness data suggest that the incorporation of Cu ions induces a change in orientation of the aliphatic chains of the amphiphiles and that amphiphile solubility in the subphase may play a role in the observed film behavior at low surface areas and high pH.
PubMed: 30747541
DOI: 10.1021/acs.langmuir.9b00022 -
FEMS Microbiology Letters Apr 2018Membrane fatty acid composition has an important role in yeast stress resistance, particularly in temperature tolerance. Most studies investigating temperature and...
Membrane fatty acid composition has an important role in yeast stress resistance, particularly in temperature tolerance. Most studies investigating temperature and membrane fatty acids use the yeast Saccharomyces cerevisiae without considering other yeasts, such as Kluyveromyces marxianus, which has physiological differences and industrial advantages with respect to S. cerevisiae. One of the primary traits of K. marxianus is its thermotolerance. The effect of fatty acid addition (oleic acid, linoleic acid, linolenic acid and araquidic acid) on the thermotolerance of the K. marxianus strain SLP1 was evaluated. SLP1 yeast exhibited temperature tolerance of up to 50°C; at 55°C, viability was reduced significantly, probably due to an increase in the generation of reactive oxygen chemical species. Externally added fatty acids were incorporated in the yeast membrane, increasing their proportion to approximately 70%, thereby changing membrane fluidity. SLP1 cells supplemented with polyunsaturated fatty acids decreased cell thermotolerance and increased the degree of lipoperoxidation, while arachidic acid addition exhibited a tendency to increase yeast thermotolerance.
Topics: Cell Membrane; Fatty Acids; Hot Temperature; Kluyveromyces; Saccharomyces cerevisiae; Thermotolerance
PubMed: 29481633
DOI: 10.1093/femsle/fny043 -
Sensors (Basel, Switzerland) Dec 2022Properties of the Langmuir-Blodgett (LB) films of arachidic and stearic acids, versus the amount of the films' monolayers were studied and applied for chloroform vapor...
Properties of the Langmuir-Blodgett (LB) films of arachidic and stearic acids, versus the amount of the films' monolayers were studied and applied for chloroform vapor detection with acoustoelectric high-frequency SAW sensors, based on an AT quartz two-port Rayleigh type SAW resonator (414 MHz) and ST-X quartz SAW delay line (157.5 MHz). Using both devices, it was confirmed that the film with 17 monolayers of stearic acid deposited on the surface of the SAW delay line at a surface pressure of 30 mN/m in the solid phase has the best sensitivity towards chloroform vapors, compared with the same films with other numbers of monolayers. For the SAW resonator sensing using slightly longer arachidic acid molecules, the optimum performance was reached with 17 LB film layers due to a sharper decrease in the Q-factor with mass loading. To understand the background of the result, Atomic Force Microscopy (AFM) in intermittent contact mode was used to study the morphology of the films, depending on the number of monolayers. The presence of the advanced morphology of the film surface with a maximal average roughness (9.3 nm) and surface area (29.7 µm) was found only for 17-monolayer film. The effects of the chloroform vapors on the amplitude and the phase of the acoustic signal for both SAW devices at 20 °C were measured and compared with those for toluene and ethanol vapors; the largest responses were detected for chloroform vapor. For the film with an optimal number of monolayers, the largest amplitude response was measured for the resonator-based device. Conversely, the largest change in the acoustic phase produced by chloroform adsorption was measured for delay-line configuration. Finally, it was established that the gas responses for both devices coated with the LB films are completely restored 60 s after chamber cleaning with dry air.
PubMed: 36616699
DOI: 10.3390/s23010100 -
Langmuir : the ACS Journal of Surfaces... Dec 2021The process of formation of a Langmuir-Schaefer (LS) matrix based on a mixed monolayer of arachidic acid (AA) and 8 nm CdSe/CdS/ZnS quantum dots (QDs) stabilized by...
The process of formation of a Langmuir-Schaefer (LS) matrix based on a mixed monolayer of arachidic acid (AA) and 8 nm CdSe/CdS/ZnS quantum dots (QDs) stabilized by molecules of trioctylphosphine oxide (TOPO) was investigated. The change in the morphology, monolayer compressibility, and area per elementary cell of the created mixed monolayers, depending on the ratio of the components, was studied. It is shown that the change in the morphology of Langmuir-Blodgett (LB) monolayers begins to occur at a ratio between the number of QDs and AA molecules of 1:24. Dendrimeric structures with a thickness of the order of 30-40 nm appear in the mixed monolayer when LB film deposition was carried out above the collapse surface pressure of a Langmuir film from only TOPO-covered QDs. Information on the dependence of the morphology of such structures on the molar ratio of the components is necessary for the production of ordered 2D nanostructures containing 0D and 1D objects with quantum bonds. Such nanostructures can be used in nanoelectronic and optoelectronic devices as a sensitive sensor element. The obtained results would be relevant for any type of spherical shape nanoparticles.
PubMed: 34793676
DOI: 10.1021/acs.langmuir.1c02345 -
Biology Jun 2021Seasonal variations in the fatty acid (FA) compositions of pollen loads collected from the Al-Ahsa Oasis in eastern Saudi Arabia throughout one year were determined to...
Seasonal variations in the fatty acid (FA) compositions of pollen loads collected from the Al-Ahsa Oasis in eastern Saudi Arabia throughout one year were determined to identify the optimal season for harvesting bee pollen rich in essential fatty acids (EFAs) and unsaturated fatty acids (UFAs). The highest values (%) of lipids, linolenic acid (C), stearic acid (C), linoleic acid (C), arachidic acid (C), the sum of the C18:0, C18:1, C18:2, and C18:3 concentrations, and EFAs were obtained from bee pollen harvested during autumn. The maximum values (%) of oleic acid (C), palmitic acid (C), UFAs, and the UFA/saturated fatty acid (SFA) ratio were found in bee pollen harvested during summer. The highest concentrations (%) of behenic acid (C), lignoceric acid (C), and SFAs were found in bee pollen harvested during winter. Bee pollen harvested during spring ranked second in its oleic, palmitic, linolenic, stearic, arachidic, behenic, and lignoceric acid concentrations and for EFAs, UFAs, and the UFA/SFA ratio. The lowest SFA concentration was found in bee pollen harvested during summer. Oleic, palmitic, and linolenic acids were the most predominant FAs found in bee pollen. It was concluded that the FA composition of bee pollen varied among the harvest seasons due to the influence of the dominant botanical origins. We recommend harvesting pollen loads during spring and summer to feed honeybee colonies during periods of scarcity and for use as a healthy, nutritious food for humans.
PubMed: 34199497
DOI: 10.3390/biology10060495 -
Molecules (Basel, Switzerland) Aug 2021Propolis is a resinous natural product collected by honeybees ( and others) from tree exudates that has been widely used in folk medicine. The present study was carried...
Propolis is a resinous natural product collected by honeybees ( and others) from tree exudates that has been widely used in folk medicine. The present study was carried out to investigate the fatty acid composition, chemical constituents, antioxidant, and xanthine oxidase (XO) inhibitory activity of Jordanian propolis, collected from Al-Ghour, Jordan. The hexane extract of Jordanian propolis contained different fatty acids, which are reported for the first time by using GC-FID. The HPLC was carried out to identify important chemical constituents such as fatty acids, polyphenols and α-tocopherol. The antioxidant and xanthine oxidase inhibitory activities were also monitored. The major fatty acid identified were palmitic acid (44.6%), oleic acid (18:1∆, 24.6%), arachidic acid (7.4%), stearic acid (5.4%), linoleic acid (18:2∆, 3.1%), caprylic acid (2.9%), lignoceric acid (2.6%), -11,14-eicosaldienoic acid (20:2∆, 2.4%), palmitoleic acid (1.5%), -11-eicosenoic acid (1.2%), α-linolenic acid (18:3∆, 1.1%), -13,16-docosadienoic acid (22:2∆, 1.0%), along with other fatty acids. The major chemical constituents identified using gradient HPLC-PDA analysis were pinocembrin (2.82%), chrysin (1.83%), luteolin-7--glucoside (1.23%), caffeic acid (1.12%), caffeic acid phenethyl ester (CAPE, 0.79%), apigenin (0.54%), galangin (0.46%), and luteolin (0.30%); while the minor constituents were hesperidin, quercetin, rutin, and vanillic acid. The percentage of α-tocopherol was 2.01 µg/g of the lipid fraction of propolis. Antioxidant properties of the extracts were determined via DPPH radical scavenging. The DPPH radical scavenging activities (IC) of different extracts ranged from 6.13 to 60.5 µg/mL compared to ascorbic acid (1.21 µg/mL). The xanthine oxidase inhibition (IC) ranged from 75.11 to 250.74 µg/mL compared to allopurinol (0.38 µg/mL). The results indicate that the various flavonoids, phenolic compounds, α-tocopherol, and other constituents which are present in propolis are responsible for the antioxidant and xanthine oxidation inhibition activity. To evaluate the safety studies of propolis, the pesticide residues were also monitored by LC-MS-MS 4500 Q-Trap. Trace amounts of pesticide residue (ng/mL) were detected in the samples, which are far below the permissible limit as per international guidelines.
Topics: Antioxidants; Caffeic Acids; Chromatography, High Pressure Liquid; Chromatography, Liquid; Fatty Acids; Flavonoids; Free Radical Scavengers; Pesticide Residues; Phenols; Phenylethyl Alcohol; Propolis; Rutin
PubMed: 34443664
DOI: 10.3390/molecules26165076 -
Current Opinion in Lipidology Feb 2022In contrast to other saturated fatty acids, very long-chain saturated fatty acids (VLSFAs) have received limited attention The purpose of this review is to summarize the... (Review)
Review
PURPOSE OF REVIEW
In contrast to other saturated fatty acids, very long-chain saturated fatty acids (VLSFAs) have received limited attention The purpose of this review is to summarize the associations of VLSFAs, including arachidic acid, behenic acid, and lignoceric acid, with cardiovascular disease outcomes and type 2 diabetes; to discuss the findings implications; and to call for future studies of the VLSFAs.
RECENT FINDINGS
Increased levels of circulating VLSFAs have been found associated with lower risks of incident heart failure, atrial fibrillation, coronary heart disease, mortality, sudden cardiac arrest, type 2 diabetes, and with better aging. The VLSFA associations are paralleled by associations of plasma ceramide and sphingomyelin species carrying a VLSFA with lower risks of heart failure, atrial fibrillation, and mortality, suggesting VLSFAs affect the biological activity of ceramides and sphingomyelins thereby impacting health. For diabetes, there is no such parallel and the associations of VLSFAs with diabetes may be confounded or mediated by triglyceride and circulating palmitic acid, possible biomarkers of de novo lipogenesis.
SUMMARY
In many ways, the epidemiology has preceded our knowledge of VLSFAs biology. We hope this review will spur interest from the research community in further studying these potentially beneficial fatty acids.
Topics: Atrial Fibrillation; Cardiovascular Diseases; Ceramides; Diabetes Mellitus, Type 2; Fatty Acids; Heart Failure; Humans
PubMed: 34907969
DOI: 10.1097/MOL.0000000000000806 -
Methods in Molecular Biology (Clifton,... 2020Lipoxygenases are key enzymes that catalyze the polyunsaturated fatty acids such as arachidic acid, linoleic acid (LA), and others unsaturated fatty acids. They are...
Lipoxygenases are key enzymes that catalyze the polyunsaturated fatty acids such as arachidic acid, linoleic acid (LA), and others unsaturated fatty acids. They are involved in important functions such as cell structure, metabolism, and signal transduction mechanisms, finally mediating cell death process, especially ferroptosis, a novel type of cell death modality. Our present protocol described a colorimetric assay for measuring lipoxygenase activity as well as a high-performance liquid chromatography/electrospray ionization tandem mass spectrometry method for the quantification of arachidonic acid metabolites.
Topics: Arachidonic Acid; Cell Line; Chromatography, High Pressure Liquid; Drug Development; Fatty Acids, Unsaturated; HEK293 Cells; Humans; Linoleic Acid; Lipoxygenases; Tandem Mass Spectrometry
PubMed: 31773660
DOI: 10.1007/978-1-0716-0163-1_17 -
International Journal of Molecular... Sep 2023Nutritional imbalances have been associated with a higher risk for cognitive impairment. This study determined the red blood cell (RBC) fatty acid profile of newly...
Nutritional imbalances have been associated with a higher risk for cognitive impairment. This study determined the red blood cell (RBC) fatty acid profile of newly diagnosed mild cognitive impairment (MCI) and Alzheimer's disease (AD) patients compared to age and gender-matched controls. There was a significant increase in palmitic acid ( < 0.00001) for both MCI and AD groups. Saturated fatty acids were significantly elevated in the MCI group, including stearic acid ( = 0.0001), arachidic acid ( = 0.003), behenic acid ( = 0.0002), tricosanoic acid ( = 0.007) and lignoceric acid ( = 0.001). n-6 polyunsaturated fatty acids (PUFAs) were significantly reduced in MCI, including linoleic acid ( = 0.001), γ-linolenic acid ( = 0.03), eicosatrienoic acid ( = 0.009) and arachidonic acid ( < 0.00004). The n-3 PUFAs, α-linolenic acid and docosahexaenoic acid, were both significantly reduced in MCI and AD ( = 0.0005 and = 0.00003). A positive correlation was evident between the Mini-Mental State Examination score and nervonic acid in MCI (r = 0.54, = 0.01) and a negative correlation with γ-linolenic acid in AD (r = -0.43, = 0.05). Differences in fatty acid profiles may prove useful as potential biomarkers reflecting increased risk for dementia.
PubMed: 37762467
DOI: 10.3390/ijms241814164