Hydroxylated Fatty Acids: The Role of the Sphingomyelin Synthase and the Origin of Selectivity

Sphingolipids are a class of lipids acting as key modulators of many physiological and pathophysiological processes. Hydroxylation patterns have a major influence on the biophysical properties of sphingolipids. In this work, we have studied the mechanism of action of hydroxylated lipids in sphingomyelin synthase (SMS). The structures of the two human isoforms, SMS1 and SMS2, have been generated through neural network supported homology. Furthermore, we have elucidated the reaction mechanism that allows SMS to recover the choline head from a phosphocholine (PC) and transfer it to ceramide, and we have clarified the role of the hydroxyl group in the interaction with the enzyme. Finally, the effect of partial inhibition of SMS on the levels of PC and sphingomyelin was calculated for different rate constants solving ordinary differential equation systems.

Luteolibacter ambystomatis sp. nov., isolated from the skin of an Anderson’s salamander (Ambystoma andersoni)

A bacterial strain designated 32AT was isolated from the skin of an Anderson’s salamander (Ambystoma andersoni) and subjected to a comprehensive taxonomic study. The strain was Gram-stain-negative, rod-shaped, non-motile, oxidase- and urease-negative, and catalase-positive. 16S rRNA gene sequence comparisons placed the strain in the genus Luteolibacter with highest sequence similarities to Luteolibacter pohnpeiensis A4T-83T (95.2%), Luteolibacter gellanilyticus CB-286403T (95.1%) and Luteolibacter cuticulihirudinis E100T (94.9%). Genomic sequence analysis revealed a size of 5.3 Mbp, a G+C-content of 62.2 mol% and highest ANI values with Luteolibacter luteus (71.2%), Luteolibacter yonseiensis (71.4%) and L. pohnpeiensis (69.5%). In the polyamine pattern, 1,3-diaminopropane and spermidine were predominant. The diagnostic diamino acid of the peptidoglycan was meso-diaminopimelic acid. The quinone system was composed of the major menaquinones MK-9 and MK-10. Major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, the unidentified aminolipid AL2, the unidentified phospholipid PL2 and the unidentified aminophospholipid APL1. The fatty acid profile contained major amounts of iso-C14:0, iso-C16:0, C16 : 0 and C16 : 1 ω9c. In addition, C14 : 0, C15:0, anteiso-C15 : 0, summed feature 2 (C14 : 0 3OH and/or iso-C16 : 0 I), and the hydroxylated fatty acids iso-C14 : 0 3OH, iso-C16 : 0 3OH and C16 : 0 3-OH were detected. Physiologically, strain 32AT is distinguishable from its next relatives. Based on phylogenetic, genomic, physiological and chemotaxonomic data, strain 32AT represents a novel species of the genus Luteolibacter for which we propose the name Luteolibacter ambystomatis sp. nov. The type strain is 32AT (=CCM 9141T=LMG 32214T).

Differential regulation of oxidative stress, microbiota-derived, and energy metabolites in the mouse brain during sleep

Sleep has evolved as a universal core function to allow for restorative biological processes. Detailed knowledge of metabolic changes necessary for the sleep state in the brain is missing. Herein, we have performed an in-depth metabolic analysis of four mouse brain regions and uncovered region-specific circadian variations. Metabolites linked to oxidative stress were altered during sleep including acylcarnitines, hydroxylated fatty acids, phenolic compounds, and thiol-containing metabolites. These findings provide molecular evidence of a significant metabolic shift of the brain energy metabolism. Specific alterations were observed for brain metabolites that have previously not been associated with a circadian function including the microbiome-derived metabolite ergothioneine that suggests a regulatory function. The pseudopeptide β-citryl-glutamate has been linked to brain development and we have now discovered a previously unknown regioisomer. These metabolites altered by the circadian rhythm represent the foundation for hypothesis-driven studies of the underlying metabolic processes and their function.

In Search of Effective Anticancer Agents—Novel Sugar Esters Based on Polyhydroxyalkanoate Monomers

Cancer is one of the deadliest illness globally. Searching for new solutions in cancer treatments is essential because commonly used mixed, targeted and personalized therapies are sometimes not sufficient or are too expensive for common patients. Sugar fatty acid esters (SFAEs) are already well-known as promising candidates for an alternative medical tool. The manuscript brings the reader closer to methods of obtaining various SFAEs using combined biological, chemical and enzymatic methods. It presents how modification of SFAE’s hydrophobic chains can influence their cytotoxicity against human skin melanoma and prostate cancer cell lines. The compound’s cytotoxicity was determined by an MTT assay, which followed an assessment of SFAEs’ potential metastatic properties in concentrations below IC50 values. Despite relatively high IC50 values (63.3–1737.6 μM) of the newly synthesized SFAE, they can compete with other sugar esters already described in the literature. The chosen bioactives caused low polymerization of microtubules and the depolymerization of actin filaments in nontoxic levels, which suggest an apoptotic rather than metastatic process. Altogether, cancer cells showed no propensity for metastasis after treating them with SFAE. They confirmed that lactose-based compounds seem the most promising surfactants among tested sugar esters. This manuscript creates a benchmark for creation of novel anticancer agents based on 3-hydroxylated fatty acids of bacterial origin.

FATTY ACID COMPOSITION OF ENDOPHYTIC MICROALGAE LAMINARIOCOLAX AECIDIOIDES, STREBLONEMA CORYMBIFERUM AND STREBLONEMA SP. (ECTOCARPALES, PHAEOPHYCEAE)

Впервые исследован жирнокислотный состав полярных и нейтральных липидов бурых эндофитных микроводорослей Laminariocolax aecidioides, Streblonema corymbiferum и Streblonema sp. Показано, что в состав полярных липидов входят главным образом полиненасыщенные жирные кислоты, такие как 18:3ω-3, 18:4ω-3 и 20:5ω-3. Во фракциях нейтральных липидов всех образцов доминировали насыщенные жирные кислоты 14:0 и 16:0, мононенасыщенная 18:1ω-9 и полиненасыщенная 18:2ω6. Отмечена высокая концентрация 16:1ω-7 в нейтральной фракции Streblonema sp. Во всех липидных фракциях эндофитов, кроме нейтральных липидов S. corymbiferum, обнаружены гидроксилированные жирные кислоты 22:0Δ2-OH и 24:0Δ2-OH. The fatty acid composition of polar and neutral lipids of brown endophytic microalgae Laminariocolax aecidioides , Streblonema corymbiferum and Streblonema sp. was investigated for the first time. It was shown that the composition of polar lipids of endophytes includes mainly polyunsaturated fatty acids, such as 18:3ω-3, 18:4ω-3 and 20: 5ω-3. Saturated 14:0 and 16:0, monounsaturated 18:1ω-9 and polyunsaturated 18:2ω6 dominated the neutral lipids of all samples. A high concentration of 16:1ω-7 was observed in the neutral fraction of Streblonema sp. Hydroxylated fatty acids 22:0Δ2-OH and 24:0Δ2-OH were found in all lipid fractions, except for neutral lipids of S. corymbiferum .

Anti-Inflammatory and Proliferative Properties of Luteolin-7-O-Glucoside

Flavonoids display a broad range of structures and are responsible for the major organoleptic characteristics of plant-derived foods and beverages. Recent data showed their activity, and in particular of luteolin-7-O-glucoside (LUT-7G), in reduction of oxidative stress and inflammatory mechanisms in different physiological systems. In this paper, we tried to elucidate how LUT-7G could exert both antioxidant and anti-inflammatory effects in endothelial cells cultured in vitro. Here, we showed that LUT-7G is able to inhibit the STAT3 pathway, to have an antiproliferative action, and an important antioxidant property in HUVEC cells. These properties are exerted by the flavone in endothelial through the transcriptional repression of a number of inflammatory cytokines and their receptors, and by the inhibition of ROS generation. ROS and STAT3 activation has been correlated with the production of oxysterols and other hydroxylated fatty acids, and they have been recognized important as players of atherogenesis and cardiocirculatory system diseases. The analysis of the general production pathway of these hydroxylated species, showed a strong decrease of cholesterol hydroxylated species such as 7-alpha-hydroxicholesterol, 7-beta-hydroxicholesterol by the treatment with LUT-7G. This confirms the anti-inflammatory properties of LUT-7G also in the endothelial district, showing for the first time the molecular pathway that verify previous postulated cardiovascular benefits of this flavone.

Olive Pomace-Derived Biomasses Fractionation through a Two-Step Extraction Based on the Use of Ultrasounds: Chemical Characteristics

Olive-derived biomass is not only a renewable bioenergy resource but also it can be a source of bioproducts, including antioxidants. In this study, the antioxidant composition of extracted olive pomace (EOP) and a new byproduct, the residual fraction from olive pit cleaning (RFOPC or residual pulp) was characterized and compared to olive leafy biomass, which have been extensively studied as a source of antioxidants and other bioactive compounds with pharmacological properties. The chemical characterization showed that these byproducts contain a high amount of extractives; in the case of EOP, it was even higher (52.9%) than in olive leaves (OL) and olive mill leaves (OML) (35.8–45.1%). Then, ultrasound-assisted extraction (UAE) was applied to recover antioxidants from the extractive fraction of these biomasses. The solubilization of antioxidants was much higher for EOP, correlating well with the extractives content and the total extraction yield. Accordingly, this also affected the phenolic richness of the extracts and the differences between all biomasses were diminished. In any case, the phenolic profile and the hydroxytyrosol cluster were different. While OL, OML, and EOP contained mainly hydroxytyrosol derivatives and flavones, RFOPC presented novel trilignols. Other compounds were also characterized, including secoiridoids, hydroxylated fatty acids, triterpenoids, among others, depending on the bioresource. Moreover, after the UAE extraction step, alkaline extraction was applied recovering a liquid and a solid fraction. While the solid fraction could of interest for further valorization as a biofuel, the liquid fraction contained proteins, sugars, and soluble lignin, which conferred antioxidant properties to these extracts, and whose content depended on the biomass and conditions applied.

Lipid A from Oligotropha carboxidovorans Lipopolysaccharide That Contains Two Galacturonic Acid Residues in the Backbone and Malic Acid A Tertiary Acyl Substituent

The free-living Gram-negative bacterium Oligotropha carboxidovorans (formerly: Pseudomonas carboxydovorans), isolated from wastewater, is able to live in aerobic and, facultatively, in autotrophic conditions, utilizing carbon monoxide or hydrogen as a source of energy. The structure of O. carboxidovorans lipid A, a hydrophobic part of lipopolysaccharide, was studied using NMR spectroscopy and high-resolution mass spectrometry (MALDI-ToF MS) techniques. It was demonstrated that the lipid A backbone is composed of two d-GlcpN3N residues connected by a β-(1→6) glycosidic linkage, substituted by galacturonic acids (d-GalpA) at C-1 and C-4’ positions. Both diaminosugars are symmetrically substituted by 3-hydroxy fatty acids (12:0(3-OH) and 18:0(3-OH)). Ester-linked secondary acyl residues (i.e., 18:0, and 26:0(25-OH) and a small amount of 28:0(27-OH)) are located in the distal part of lipid A. These very long-chain hydroxylated fatty acids (VLCFAs) were found to be almost totally esterified at the (ω-1)-OH position with malic acid. Similarities between the lipid A of O. carboxidovorans and Mesorhizobium loti, Rhizobium leguminosarum, Caulobacter crescentus as well as Aquifex pyrophylus were observed and discussed from the perspective of the genomic context of these bacteria.