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The Journal of Physical Chemistry. C,... May 2022The adsorption of carboxylic acid molecules at the calcite (104) and the muscovite (001) surface was investigated using surface X-ray diffraction. All four investigated...
The adsorption of carboxylic acid molecules at the calcite (104) and the muscovite (001) surface was investigated using surface X-ray diffraction. All four investigated carboxylic acid molecules, hexanoic acid, octanoic acid, lauric acid, and stearic acid, were found to adsorb at the calcite surface. Whereas the shortest two carboxylic acid molecules, hexanoic acid and octanoic acid, showed limited ordering and a flexible, disordered chain, the two longest carboxylic acid molecules form fully ordered monolayers, i.e., these form highly structured self-assembled monolayers. The latter molecules are oriented almost fully upright, with a tilt of up to 10°. The oxygen atoms of the organic molecules are found at similar positions to those of water molecules at the calcite-water interface. This suggests that in both cases, the oxygen atoms compensate for the broken bonds at the calcite surface. Under the same experimental conditions, stearic acid does not adsorb to K and Ca-functionalized muscovite mica because the neutral molecules do not engage in the ionic bonds typical for the mica interface. These differences in adsorption behavior are characteristic for the differences of the oil-solid interactions in carbonate and sandstone reservoirs.
PubMed: 35655936
DOI: 10.1021/acs.jpcc.2c01157 -
FEMS Yeast Research Mar 2021The medium-chain fatty acid octanoic acid is an important platform compound widely used in industry. The microbial production from sugars in Saccharomyces cerevisiae is...
The medium-chain fatty acid octanoic acid is an important platform compound widely used in industry. The microbial production from sugars in Saccharomyces cerevisiae is a promising alternative to current non-sustainable production methods, however, titers need to be further increased. To achieve this, it is essential to have in-depth knowledge about the cell physiology during octanoic acid production. To this end, we collected the first RNA-Seq data of an octanoic acid producer strain at three time points during fermentation. The strain produced higher levels of octanoic acid and increased levels of fatty acids of other chain lengths (C6-C18) but showed decreased growth compared to the reference. Furthermore, we show that the here analyzed transcriptomic response to internally produced octanoic acid is notably distinct from a wild type's response to externally supplied octanoic acid as reported in previous publications. By comparing the transcriptomic response of different sampling times, we identified several genes that we subsequently overexpressed and knocked out, respectively. Hereby we identified RPL40B, to date unknown to play a role in fatty acid biosynthesis or medium-chain fatty acid tolerance. Overexpression of RPL40B led to an increase in octanoic acid titers by 40%.
Topics: Biosynthetic Pathways; Caprylates; Fermentation; Gene Expression Profiling; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
PubMed: 33599754
DOI: 10.1093/femsyr/foab011 -
World Health Organization Technical... 2017This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a...
This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to concluding as to safety concerns and to preparing specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee’s evaluations of technical, toxicological and dietary exposure data for 10 food additives (Allura Red AC; carob bean gum; lutein esters from Tagetes erecta; octenyl succinic acid (OSA)– modified gum arabic; pectin; Quinoline Yellow; rosemary extract; steviol glycosides; tartrazine; and xanthan gum) and five groups of flavouring agents (alicyclic, alicyclic-fused and aromatic-fused ring lactones; aliphatic and aromatic amines and amides; aliphatic secondary alcohols, ketones and related esters; cinnamyl alcohol and related substances; and tetrahydrofuran and furanone derivatives). Specifications for the following food additives were revised: aspartame; cassia gum; citric and fatty acid esters of glycerol (CITREM); modified starches; octanoic acid; starch sodium octenyl succinate; and total colouring matters. Annexed to the report are tables summarizing the Committee’s recommendations for dietary exposures to and toxicological evaluations of all of the food additives, including flavouring agents, considered at this meeting.
Topics: Flavoring Agents; Food Additives; Food Safety; Humans; World Health Organization
PubMed: 29144073
DOI: No ID Found -
The Journal of Physical Chemistry... Apr 2021Perfluorinated acids (PFAs) are widely used synthetic chemical compounds, highly resistant to environmental degradation. The widespread PFA contamination in remote...
Perfluorinated acids (PFAs) are widely used synthetic chemical compounds, highly resistant to environmental degradation. The widespread PFA contamination in remote regions such as the High Arctic implies currently not understood long-range atmospheric transport pathways. Here, we report that perfluorooctanoic acid (PFOA) initiates heterogeneous ice nucleation at temperatures as high as -16 °C. In contrast, the eight-carbon octanoic acid, perfluorooctanesulfonic acid, and deprotonated PFOA showed poor ice nucleating capabilities. The ice nucleation ability of PFOA correlates with the formation of a PFOA monolayer at the air-water interface, suggesting a mechanism in which the aligned hydroxyl groups of the carboxylic acid moieties provide a lattice matching to ice. The ice nucleation capabilities of fluorinated compounds like PFOA might be relevant for cloud glaciation in the atmosphere and the removal of these persistent pollutants by wet deposition.
PubMed: 33789043
DOI: 10.1021/acs.jpclett.1c00604 -
Molecules (Basel, Switzerland) Nov 2021In addition to dermatological complications, acne can affect the quality of life of individuals in numerous ways, such as employment, social habits and body...
In addition to dermatological complications, acne can affect the quality of life of individuals in numerous ways, such as employment, social habits and body dissatisfaction. According to our expertise, caprylic acid and propanediol would not have a direct action on . Despite this, we investigated the existence of a synergistic effect among xylitol, caprylic acid and propanediol as a mixture of compounds representing a single topical active ingredient that could benefit the treatment against acne. In vitro and in vivo assays were performed to challenge and to prove the efficacy of propanediol, xylitol and caprylic acid (PXCA) against acne. PXCA had its MIC challenged against (formerly ) and , resulting in concentrations of 0.125% and 0.25%, respectively, and it also developed antimicrobial activity against (time-kill test). PXCA was able to reduce the 5-alpha reductase expression in 24% ( < 0.01) in comparison with the testosterone group. By the end of 28 days of treatment, the compound reduced the skin oiliness, porphyrin amount and the quantity of inflammatory lesions in participants. According to the dermatologist evaluation, PXCA improved the skin's general appearance, acne presence and size.
Topics: Acne Vulgaris; Anti-Bacterial Agents; Anti-Inflammatory Agents; Caprylates; Clinical Trials as Topic; Disease Management; Disease Susceptibility; Humans; Microbial Sensitivity Tests; Propylene Glycols; Staphylococcus aureus; Treatment Outcome; Xylitol
PubMed: 34771112
DOI: 10.3390/molecules26216704 -
Prostaglandins, Leukotrienes, and... Aug 2018Caprylic acid (octanoic acid, C8:0) belongs to the class of medium-chain saturated fatty acids (MCFAs). Dairy products and specific oils such as coconut oil are natural... (Review)
Review
Caprylic acid (octanoic acid, C8:0) belongs to the class of medium-chain saturated fatty acids (MCFAs). Dairy products and specific oils such as coconut oil are natural sources of dietary caprylic acid. MCFAs display distinct chemico-physical and metabolic properties from those of long-chain saturated fatty acids (LCFAs ≥ 12 carbons) and potential beneficial physiological effects of dietary C8:0 have been studied for many years. More recently, caprylic acid was shown to octanoylate ghrelin, the only known peptide hormone with an orexigenic effect. Through its covalent binding to the ghrelin peptide, caprylic acid exhibits an emerging and specific role in modulating physiological functions themselves regulated by octanoylated ghrelin. Dietary caprylic acid is therefore now suspected to provide the ghrelin O-acyltransferase (GOAT) enzyme with octanoyl-CoA co-substrates necessary for the acyl modification of ghrelin. Recent studies suggest that decreasing the circulating octanoylated ghrelin level through the inhibition of GOAT activity, or simply by modulating the availability of its C8:0 substrate, might constitute a therapeutic strategy against obesity. Both dietary caprylic acid availability and GOAT activity may indeed be important to modulate octanoylated ghrelin concentration and functions. This review highlights recent findings in the field of nutrition.
Topics: Acyltransferases; Animals; Caprylates; Coconut Oil; Dairy Products; Dietary Fats; Ghrelin; Humans; Nutritional Status; Obesity
PubMed: 30103923
DOI: 10.1016/j.plefa.2018.07.009 -
BMC Biology Feb 2022In insects, airborne chemical signals are mainly detected by two receptor families, odorant receptors (ORs) and ionotropic receptors (IRs). Functions of ORs have been...
BACKGROUND
In insects, airborne chemical signals are mainly detected by two receptor families, odorant receptors (ORs) and ionotropic receptors (IRs). Functions of ORs have been intensively investigated in Diptera and Lepidoptera, while the functions and evolution of the more ancient IR family remain largely unexplored beyond Diptera.
RESULTS
Here, we identified a repertoire of 26 IRs from transcriptomes of female and male antennae, and ovipositors in the moth Agrotis segetum. We observed that a large clade formed by IR75p and IR75q expansions is closely related to the acid-sensing IRs identified in Diptera. We functionally assayed each of the five AsegIRs from this clade using Xenopus oocytes and found that two receptors responded to the tested ligands. AsegIR75p.1 responded to several compounds but hexanoic acid was revealed to be the primary ligand, and AsegIR75q.1 responded primarily to octanoic acid, and less so to nonanoic acid. It has been reported that the C-C medium-chain fatty acids repel various insects including many drosophilids and mosquitos. We show that the C-C medium-chain fatty acids elicited antennal responses of both sexes of A. segetum, while only octanoic acid had repellent effect to the moths in a behavioral assay. In addition, using fluorescence in situ hybridization, we demonstrated that the five IRs and their co-receptor AsegIR8a are not located in coeloconic sensilla as found in Drosophila, but in basiconic or trichoid sensilla.
CONCLUSIONS
Our results significantly expand the current knowledge of the insect IR family. Based on the functional data in combination with phylogenetic analysis, we propose that subfunctionalization after gene duplication plays an important role in the evolution of ligand specificities of the acid-sensing IRs in Lepidoptera.
Topics: Animals; Arthropod Antennae; Brassica napus; Caprylates; Diptera; Female; In Situ Hybridization, Fluorescence; Insect Proteins; Ligands; Male; Moths; Phylogeny; Receptors, Odorant
PubMed: 35130883
DOI: 10.1186/s12915-022-01235-0 -
Journal of Voice : Official Journal of... Jan 2022Essential vocal tremor (EVT) is an uncommon but challenging condition to manage. Several medical and interventional treatment options have been reported but efficacy... (Review)
Review
OBJECTIVES/HYPOTHESIS
Essential vocal tremor (EVT) is an uncommon but challenging condition to manage. Several medical and interventional treatment options have been reported but efficacy remains unclear. We performed a scoping review of high-quality clinical trials to identify effective evidence-based treatments for EVT.
STUDY DESIGN
Scoping review.
METHODS
Relevant studies were identified using the databases MedLine, Cochrane Central Register of Controlled Trials, and Embase. Subjective and objective outcomes for each modality were analyzed and the effect sizes were quantified using Hedges' g measure to allow comparison between studies.
RESULTS
We identified 421 studies eligible for screening with 11 included in the final analysis. Evidence supporting effective EVT treatments was found for bilateral versus unilateral deep brain stimulation (DBS) (Hedges' g 0.65, 95% CI = 0.10-1.20) and octanoic acid (Hedges' g 1.15, 95% CI = 0.40-1.90). Evidence to support the use of methazolamide was not sufficient (Hedges' g 0.51, 95% CI = -0.64 to 1.66). Botulinum toxin (BT) injections were equivalent when comparing unilateral versus bilateral (Hedges' g -0.18, 95% CI = -1.06 to 0.70); BT did not display any advantage over propranolol (Hedges' g -0.47, 95% CI = -1.73 to 0.78) or injection augmentation (Hedges' g 0.068, 95% CI = -0.98 to 1.12).
CONCLUSIONS
Our review finds very little high-quality evidence supporting any treatment for EVT. Octanoic acid reduced fluctuations in EVT but did not affect the perception of the tremor. In refractory cases, bilateral DBS was superior to unilateral DBS in improving subjective voice outcomes. Unilateral and bilateral BT injections were equivalent, and BT injection was not more effective than injection augmentation. Further direct comparison in well-designed prospective studies may help clarify optimal treatment for EVT patients.
PubMed: 35022154
DOI: 10.1016/j.jvoice.2021.12.009 -
Nutrients Dec 2022Medium-chain fatty acids contain 6-12 carbon atoms and are absorbed directly into the blood vessels, proceeding to the portal vein and, finally, to the liver, where...
Medium-chain fatty acids contain 6-12 carbon atoms and are absorbed directly into the blood vessels, proceeding to the portal vein and, finally, to the liver, where they are immediately utilized for energy. We aimed to determine the medium-chain fatty acid levels in women with and without breast cancer. A total of 200 women (100 breast cancer subjects and 100 control subjects) were recruited for the study as per the inclusion and exclusion criteria. Blood samples were collected for biochemical estimations. Fatty acid methyl esters were isolated, and medium-chain fatty acid levels in plasma were analyzed using gas chromatography (GC-FID). Statistical analysis was performed using SPSS 20.0 software; ≤ 0.05 was considered statistically significant. The fatty acid analysis revealed a significant decrease in the levels of caprylic acid (C:8) and lauric acid (C:12) and a significant increase in the level of capric acid (C:10) in the breast cancer subjects when compared to the control group. The level of caproic acid (C:6) was not significantly increased in the breast cancer subjects. In particular, the HER2- and ER-positive breast cancer subjects showed a decrease in their caprylic acid and lauric acid levels compared to other receptors. The results of the current study imply that lower levels of caprylic and lauric acid may be associated with a higher risk of breast cancer. The relevance of medium-chain fatty acids for preventive and therapeutic interventions will be amplified by further research on the possibility that alteration in a patient's medium-chain fatty acid composition may mechanistically contribute to disease progression or breast cancer risk.
Topics: Humans; Female; Caprylates; Breast Neoplasms; Fatty Acids; Lauric Acids
PubMed: 36558514
DOI: 10.3390/nu14245351 -
Mycoses Dec 2022Malassezia (M.) pachydermatis as a frequent reason for dermatological consultation in dogs and cats was recently shown to be lipid-dependent, too. Lipolytic activity is...
BACKGROUND
Malassezia (M.) pachydermatis as a frequent reason for dermatological consultation in dogs and cats was recently shown to be lipid-dependent, too. Lipolytic activity is a prerequisite for activating antimicrobial effectivity of fatty acid esters.
OBJECTIVES
It was therefore of interest whether it is possible to induce this mechanism in M. pachydermatis and to identify possible differences between minimal and strong lipid-dependent strains.
METHODS
In an agar dilution test, the minimal inhibitory concentrations of six fatty acid esters were determined for seventeen M. pachydermatis strains. GC analysis of parent compounds and liberated fatty acids was used to quantify ester cleavage.
RESULTS
Hydrolysis was observed in all test strains in a homogenous manner but was dependent on the chemical structure. Lowest MICs (500 ppm after 14 days of incubation) were obtained applying glyceryl monocaprylate and 3-hydroxylpropyl caprylate, while the corresponding esters of undecylenic acid showed nearly twice the value. As shown by GC analysis with the reference strains CBS 1879 and CBS 1892 and 3-hydroxypropyl caprylate, hydrolysis and caprylic acid formation starts immediately and was dependent on yeast density. Furthermore, nine azole-resistant strains isolated from dogs with treatment failures showed MIC values comparable to the other strains and no resistance to monohydric fatty acid esters.
CONCLUSIONS
Medium-chain fatty acid esters may represent a new therapeutic option for veterinary use even in azole-resistant strains. The in vivo verification in M. pachydermatis-associated dermatitis in dogs and cats will be the next step for the successful development of new therapeutics.
Topics: Dogs; Cats; Animals; Malassezia; Azoles; Caprylates; Esters; Cat Diseases; Antifungal Agents; Dog Diseases; Fatty Acids; Dermatomycoses
PubMed: 35923130
DOI: 10.1111/myc.13512