Inhibition of AI-2 Quorum Sensing and Biofilm Formation in Campylobacter jejuni by Decanoic and Lauric Acids

Campylobacter jejuni is a major bacterial cause of human diarrheal diseases worldwide. Despite its sensitivity to environmental stresses, C. jejuni ubiquitously distributes throughout poultry production chains. Biofilm formation mediated by quorum sensing is suggested to be critical to the survival of C. jejuni in agroecosystem. C. jejuni possesses LuxS, the enzyme involved in the production of autoinducer-2 (AI-2) signaling molecules. In this study, two fatty acids, namely decanoic acid and lauric acid, were identified to be effective in inhibiting AI-2 activity of C. jejuni. Both decanoic acid and lauric acid at 100 ppm inhibited ∼90% AI-2 activity (P < 0.05) of C. jejuni without bacterial inactivation. The biofilm biomass of two C. jejuni strains was reduced by 10–50% (P < 0.05) after treatment by both fatty acids, while increased biofilm formation was observed for one C. jejuni strain. In addition, both fatty acids effectively reduced the motility of all tested C. jejuni strains. These findings can aid in developing alternative C. jejuni control strategies in agri-food and clinical settings.

Deep Eutectic Solvent-Functionalized Mesoporous Silica SBA-15-Based Mixed Matrix Polymeric Membranes for Mitigation of CO2

In this research, a novel DES (choline chloride + decanoic acid) was synthesized, and SBA-15 was functionalized by the DES to form a DES-SBA filler to fabricate MMMs. DES-SBA-based MMMs at 5%, 10%, 15%, and 20% were synthesized and evaluated. The DES-SBA-based MMMs were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Gas permeation tests were applied to the pure and mixed gas samples, and the results of the permeability and selectivity (CO2/CH4, and CO2/N2) of the membranes are reported. DES modification of SBA-15 increased the efficiency of the synthesized MMMs in comparison with the pristine polysulfone membrane.

Analysis of the Effects of Food Additives on Porphyromonas gingivalis

This study aims to investigate six food additives (octanoic acid, decanoic acid, acesulfame K, aspartame, saccharin, and sucralose) used in foods for the elderly or people with dysphagia because of the effect of these food additives on Porphyromonas gingivalis (P. gingivalis), which is a keystone pathogen of periodontal diseases. The growth of P. gingivalis was inhibited by 5 mM octanoic acid, 1.25 mM decanoic acid, 1.25% acesulfame K, 0.0625% aspartame, 0.03125% saccharin, and 0.625% sucralose. In addition, these food additives showed bactericidal activity for planktonic P. gingivalis (5 mM octanoic acid, 5 mM decanoic acid, 0.25% aspartame, 0.25% saccharin, and 5% sucralose). Moreover, biofilm formation was inhibited by 10 mM octanoic acid, 10 mM decanoic acid, 10% acesulfame K, 0.35% aspartame, 0.5% saccharin, and 7.5% sucralose. Moreover, the same concentration of these food additives without aspartame killed P. gingivalis in the biofilm. Aspartame and sucralose did not show cytotoxicity to human cell lines at concentrations that affected P. gingivalis. These findings may be useful in clarifying the effects of food additives on periodontopathogenic bacteria.

“Portugizac Mlado vino”; is the aroma of younger red wine more attractive?

“Portugizac Mlado vino” is a local red wine with Protected designation of origin and Traditional term, and it is usually consumed very soon after alcoholic fermentation as a young wine. The maturation and aging of the wine affect the aroma composition, which is generally not pronounced and specific in the case of most red wines, but, as a sensory property, it is important for the perception of quality and consumer choice. The objective of this work was to analyze the most important aroma compounds of esters and higher alcohols, with the unpleasant volatile phenols too, in “Portugizac” wines, related to aging. The 9 young wines “Portugizac”, PDO “Plešivica” were analyzed after 3 and after 15 months of bottle storage at 16 ºC. Ethyl esters of butanoic and hexanoic acid along with isoamyl acetate are considered to be the most important esters in the fruity aroma of wine, and their concentrations in all analyzed “Portugizac” young wine samples were higher than their perception thresholds. The concentration of ethyl acetate was in the range 30-123 mg/L. The concentrations of ethyl esters of octanoic and decanoic acid, as well as 2-phenyl ethyl acetate and diethyl succinate in all analyzed wines, were lower than their perception thresholds. The concentrations of higher alcohols were much higher than their perception threshold. Bottle storage significantly affected the concentrations of analyzed compounds; after 15 months, the concentrations of acetate and ethyl esters (except ethyl acetate and diethyl succinate), as well as terpene (linalool), decreased, while higher alcohols and ethyl phenols slightly increased if compared to three months. In general, the compounds responsible for the desired fresh, fruity aroma tones were altered in an undesirable manner, while, undesirable compounds of 4-ethyl-phenol and 4-ethyl-quaiacol, which were not present in young wines, were detected in aged wines. It can be concluded that the bottle aging affects the aroma profile, undesirable changes were more pronounced than positive ones and therefore the consumption of young wine “Portugizac” might be more sensory attractive.

Decanoic Acid Stimulates Autophagy in D. discoideum

Ketogenic diets, used in epilepsy treatment, are considered to work through reduced glucose and ketone generation to regulate a range of cellular process including autophagy induction. Recent studies into the medium-chain triglyceride (MCT) ketogenic diet have suggested that medium-chain fatty acids (MCFAs) provided in the diet, decanoic acid and octanoic acid, cause specific therapeutic effects independent of glucose reduction, although a role in autophagy has not been investigated. Both autophagy and MCFAs have been widely studied in Dictyostelium, with findings providing important advances in the study of autophagy-related pathologies such as neurodegenerative diseases. Here, we utilize this model to analyze a role for MCFAs in regulating autophagy. We show that treatment with decanoic acid but not octanoic acid induces autophagosome formation and modulates autophagic flux in high glucose conditions. To investigate this effect, decanoic acid, but not octanoic acid, was found to induce the expression of autophagy-inducing proteins (Atg1 and Atg8), providing a mechanism for this effect. Finally, we demonstrate a range of related fatty acid derivatives with seizure control activity, 4BCCA, 4EOA, and Epilim (valproic acid), also function to induce autophagosome formation in this model. Thus, our data suggest that decanoic acid and related compounds may provide a less-restrictive therapeutic approach to activate autophagy.

Multiunit In Vitro Colon Model for the Evaluation of Prebiotic Potential of a Fiber Plus D-Limonene Food Supplement

The search for new fiber supplements that can claim to be “prebiotic” is expanding fast, as the role of prebiotics and intestinal microbiota in well-being has been well established. This work explored the prebiotic potential of a novel fiber plus D-Limonene supplement (FLS) in comparison to fructooligosaccharides (FOS) over distal colonic fermentation with the in vitro model MICODE (multi-unit in vitro colon gut model). During fermentation, volatilome characterization and core microbiota quantifications were performed, then correlations among volatiles and microbes were interpreted. The results indicated that FLS generated positive effects on the host gut model, determining: (i) eubiosis; (ii) increased abundance of beneficial bacteria, as Bifidobacteriaceae; (iii) production of beneficial compounds, as n-Decanoic acid; (iv) reduction in detrimental bacteria, as Enterobaceteriaceae; (v) reduction in detrimental compounds, as skatole. The approach that we followed permitted us to describe the prebiotic potential of FLS and its ability to steadily maintain the metabolism of colon microbiota over time. This aspect is two-faced and should be investigated further because if a fast microbial turnover and production of beneficial compounds is a hallmark of a prebiotic, the ability to reduce microbiota changes and to reduce imbalances in the productions of microbial metabolites could be an added value to FLS. In fact, it has been recently demonstrated that these aspects could serve as an adjuvant in metabolic disorders and cognitive decline.

LORE homomerization is required for 3-OH-C10:0 induced immune signaling

Perception and processing of various internal and external signals is essential for all living organisms. Plants have an expanded and diversified repertoire of cell surface-localized receptor-like kinases (RLKs) that transduce signals across the plasma membrane. RLKs often assemble into higher-order receptor complexes with co-receptors, regulators and scaffolds to convert extracellular stimuli into cellular responses. To date, the only S-domain-RLK from Arabidopsis thaliana with a known ligand and function is AtLORE, a pattern recognition receptor that senses bacterial 3-hydroxy fatty acids of medium chain length, such as 3-hydroxy decanoic acid (3-OH-C10:0), to activate pattern-triggered immunity. Here we show that AtLORE forms receptor homomers, which is essential for 3-OH-C10:0-induced immune signaling. AtLORE homomerization is mediated by the transmembrane and extracellular domain. We show natural variation in the perception of 3-OH-C10:0 within the Brassicaceae family. Arabidopsis lyrata and Arabidopsis halleri do not respond to 3-OH-C10:0, although they possess a putative LORE orthologue. We found that LORE orthologues of these 3-OH-C10:0 nonresponsive species have defective extracellular domains that can bind the 3-OH-C10:0 ligand but lack the ability to homomerize. Our findings shed light on the activation mechanisms of AtLORE and explain natural variation of 3-OH-C10:0 perception within the Brassicaceae family.

Amino Acid-Based Natural Deep Eutectic Solvents for Extraction of Phenolic Compounds from Aqueous Environments

The environmental pollution of phenol-containing wastewater is an urgent problem with industrial development. Natural deep eutectic solvents provide an environmentally friendly alternation for the solvent extraction of phenol. This study synthesized a series of natural deep eutectic solvents with L-proline and decanoic acid as precursors, characterized by in situ infrared spectrometry, Fourier transform infrared spectrometry, hydrogen nuclear magnetic resonance spectrometry, and differential thermogravimetric analysis. Natural deep eutectic solvents have good thermal stability. The high-efficiency extraction of phenol from wastewater by natural deep eutectic solvents was investigated under mild conditions. The effects of natural deep eutectic solvents, phenol concentration, reaction temperature, and reaction time on phenol extraction were studied. The optimized extraction conditions of phenol with L-prolin/decanoic acid were as follows: molar ratio, 4.2:1; reaction time, 60 min; and temperature, 50 °C. Extraction efficiency was up to 62%. The number of extraction cycles can be up to 6, and extraction rate not less than 57%. The promising results demonstrate that natural deep eutectic solvents are efficient in the field of phenolic compound extraction in wastewater.