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High-resolution ion mobility (resolving power > 200) coupled with mass spectrometry (MS) is a powerful analytical tool for resolving isobars and isomers in complex samples. High-resolution ion mobility is capable of discerning additional structurally distinct features, which are not observed with conventional resolving power ion mobility (IM, resolving power ~ 50) techniques such as traveling wave IM and drift tube ion mobility (DTIM). DTIM in particular is considered to be the "gold standard" IM technique since collision cross section (CCS) values are directly obtained through a first-principles relationship, whereas traveling wave IM techniques require an additional calibration strategy to determine accurate CCS values. In this study, we aim to evaluate the separation capabilities of a traveling wave ion mobility structures for lossless ion manipulation platform integrated with mass spectrometry analysis (SLIM IM-MS) for both lipid isomer standards and complex lipid samples. A cross-platform investigation of seven subclass-specific lipid extracts examined by both DTIM-MS and SLIM IM-MS showed additional features were observed for all lipid extracts when examined under high resolving power IM conditions, with the number of CCS-aligned features that resolve into additional peaks from DTIM-MS to SLIM IM-MS analysis varying between 5 and 50%, depending on the specific lipid sub-class investigated. Lipid CCS values are obtained from SLIM IM (TW(SLIM)CCS) through a two-step calibration procedure to align these measurements to within 2% average bias to reference values obtained via DTIM (DTCCS). A total of 225 lipid features from seven lipid extracts are subsequently identified in the high resolving power IM analysis by a combination of accurate mass-to-charge, CCS, retention time, and linear mobility-mass correlations to curate a high-resolution IM lipid structural atlas. These results emphasize the high isomeric complexity present in lipidomic samples and underscore the need for multiple analytical stages of separation operated at high resolution. [ABSTRACT FROM AUTHOR]

The aim of this study is to reveal the molecular changes accompanying the neuronal hyper‐excitability during lipopolysaccharide (LPS)‐induced systemic inflammation on rat hippocampus using Fourier transform infrared (FTIR) spectroscopy. For this aim, the body temperature of Wistar albino rats administered LPS or saline was recorded by radiotelemetry. The animals were decapitated when their body temperature began to decrease by 0.5°C after LPS treatment and the hippocampi of them were examined by FTIR spectroscopy. The results indicated that systemic inflammation caused lipid peroxidation, an increase in the amounts of lipids, proteins and nucleic acids, a decrease in membrane order, an increase in membrane dynamics and changes in the secondary structure of proteins. Principal component analysis successfully separated control and LPS‐treated groups. In conclusion, significant structural, compositional and functional alterations occur in the hippocampus during systemic inflammation and these changes may have specific characteristics which can lead to neuronal hyper‐excitability. [ABSTRACT FROM AUTHOR]

Infant follow‐on formulas (IFF) mimic human milk. This study aimed to identify the key structural levers that influence oxidative stability of IFF. Representative model IFF of marketed products in term of lipid composition were formulated with varying droplet size, lipid droplet core composition, and interfacial composition using different emulsifiers (soy lecithin or dairy phospholipids [DPL]). The oxidative stability of model IFF was assessed in accelerated storage conditions. No significant stabilization effect based on the lipid droplet core composition was observed. However, the nature of the interface, influenced by the emulsifier type, had an impact. Model IFF with DPL showed no loss of tocopherols and peroxide value was up to twice lower than those with soy lecithin after 20 days. This effect was particularly pronounced for the 0.4µm droplets. These results suggest that model IFF with DPL had a greater oxidative stability, likely due to the presence of sphingomyelin and the formation of a rigidified domain at the droplet surface. Model IFF with 0.4 µm droplets stabilized with soy lecithin, especially when added to the water phase, showed a tocopherols loss twice as high as that of IFF with DPL. These results indicate that oxidative stability of IFF is more influenced by the chemical environment rather than droplet size. Practical Application: Infant follow‐on formulas (IFF) aim to ensure an adequate nutritional intake to support the proper development and infant growth. Therefore, IFF must be stable against degradation phenomena such as lipid oxidation and have a composition and structure that are as biomimetic as possible to mature breast milk. This study provides key information for the development of IFF with a lipid composition and structure that are suitable for the infant nutritional needs and have an acceptable resistance to lipid oxidation. More generally, these results can be applied to all dispersed systems in the form of oil‐in‐water emulsions with a similar composition. [ABSTRACT FROM AUTHOR]

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GPCRs receive signals from diverse messengers and activate G proteins that regulate downstream signaling effectors. Efficient signaling is achieved through the organization of these proteins in membranes. Thus, protein–lipid interactions play a critical role in bringing G proteins together in specific membrane microdomains with signaling partners. Significantly, the molecular basis underlying the membrane distribution of each G protein isoform, fundamental to fully understanding subsequent cell signaling, remains largely unclear. We used model membranes with lipid composition resembling different membrane microdomains, and monomeric, dimeric and trimeric Gi proteins with or without single and multiple mutations to investigate the structural bases of G protein–membrane interactions. We demonstrated that cationic amino acids in the N-terminal region of the Gαi1 and C-terminal region of the Gγ2 subunit, as well as their myristoyl, palmitoyl and geranylgeranyl moieties, define the differential G protein form interactions with membranes containing different lipid classes (PC, PS, PE, SM, Cho) and the various microdomains they may form (Lo, Ld, PC bilayer, charged, etc.). These new findings in part explain the molecular basis underlying amphitropic protein translocation to membranes and localization to different membrane microdomains and the role of these interactions in cell signal propagation, pathophysiology and therapies targeted to lipid membranes. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate the effect of monoterpenoid hinokitiol (β-thujaplicin) on the monolayers and bilayers composed of lipids typical for bacteria membranes and gain insight into the potential role of the lipids in antibacterial activity and selectivity of this compound. To explore this issue, the in vitro studies were performed on different bacterial strains to verify antibacterial potency of hinokitiol. Then, the experiments on E. coli and S. aureus bacteria membrane models (i.e. multicomponent lipid monolayers and bilayers) were done. Finally, the effect of hinokitiol on one component lipid monolayers was investigated. The lipids used in the experiments included Phosphatidylethanolamines (PEs), Phosphatidylglycerols (PGs) and Cardiolipins differing in the structure of the polar head and/or the hydrophobic chains. This choice allowed the analysis of correlations between the lipid structure and the effect of hinokitiol. In vitro tests confirmed the antimicrobial activity of hinokitiol against most of the strains tested. In addition, the in vitro tests showed that E. coli bacteria were more sensitive to hinokitiol than S. aureus bacteria. Interestingly, the studies on model systems evidenced that hinokitiol molecules are of stronger effect on E.coli film and they are able to insert into these systems even at membrane-related surface pressures. Moreover, the structure of the lipid and its content in the model system correlated with the effect exerted by hinokitiol on the monolayer properties. It was found that hinokitiol differs in the affinity to particular lipids and additionally hinokitiol/lipid interactions may occur according to different mechanisms. Namely, depending on the lipid structure, hinokitiol may incorporate into the lipid film (Cardiolipins and PEs) or interact preferentially with the lipid polar head (PGs) and form hydrogen bonds. The effect of hinokitiol on the lipids was determined by the charge and size of the polar head as well as by the spatial size of the lipid molecule. Moreover, comparing the lipids of the same polar heads, hinokitiol caused stronger expansion of the film formed from the lipid having unsaturated chains. The results obtained may explain the difference in the effect of hinokitiol on particular bacterial strains. In conclusions, it can be suggested that the lipids should be considered as the bacteria membrane structural elements of a possible role in the mechanism of action of hinokitiol. [Display omitted] • Hinokitiol shows antimicrobial activity against various bacteria strains in in vitro tests. • The results obtained indicate on the role of lipids in the activity of hinokitiol. • Hinokitiol/lipid interactions are determined by the lipid structure. • Differences in the affinity of hinokitiol to particular lipids may explain hinokitiol selectivity. [ABSTRACT FROM AUTHOR]

Cellular membranes are formed from different lipids in various amounts and proportions depending on the subcellular localization. The lipid composition of membranes is sensitive to changes in the cellular environment, and its alterations are linked to several diseases. Lipids not only form lipid-lipid interactions but also interact with other biomolecules, including proteins.Molecular dynamics (MD) simulations are a powerful tool to study the properties of cellular membranes and membrane-protein interactions on different timescales and resolutions. Over the last few years, software and hardware for biomolecular simulations have been optimized to routinely run long simulations of large and complex biological systems. On the other hand, high-throughput techniques based on lipidomics provide accurate estimates of the composition of cellular membranes at the level of subcellular compartments. Lipidomic data can be analyzed to design biologically relevant models of membranes for MD simulations. Similar applications easily result in a massive amount of simulation data where the bottleneck becomes the analysis of the data. In this context, we developed LipidDyn, a Python-based pipeline to streamline the analyses of MD simulations of membranes of different compositions. Once the simulations are collected, LipidDyn provides average properties and time series for several membrane properties such as area per lipid, thickness, order parameters, diffusion motions, lipid density, and lipid enrichment/depletion. The calculations exploit parallelization, and the pipeline includes graphical outputs in a publication-ready form. We applied LipidDyn to different case studies to illustrate its potential, including membranes from cellular compartments and transmembrane protein domains. LipidDyn is available free of charge under the GNU General Public License from https://github.com/ELELAB/LipidDyn.

This study aimed to investigate the effects of fatty acid (FA) type on the binding state, fine structure, and digestibility of debranched maize starch (DMS)-FA complexes with different enzymatic debranching degrees. Maize starch was hydrolyzed by pullulanase for 1 h (DMS1h) and 6 h (DMS6h) and then complexed with seven types of FAs with varying chain lengths and unsaturation degrees, respectively. All the DMS-FA complexes showed V 6III -type and B-type crystals. Complex formation greatly increased the relative crystallinity of DMS, but significantly decreased its order degree of short-range structure (p < 0.05). Compared with unsaturated FAs, saturated FAs possessed stronger intermolecular interactions with DMS. DMS6h-FA complexes exhibited a markedly higher complexing degree (p < 0.05) than the corresponding DMS1h-FA complexes. The FA molecules in DMS1h-FA complexes were primarily physically trapped outside the amylose helices, whereas those in DMS6h-FA complexes were mainly weakly bound to the cavity of amylose helices. The resistant starch (RS) content and relative crystallinity of DMS-FA complexes considerably increased with increasing FA chain length. Furthermore, the highest RS content (38.90 %) and relative crystallinity (24.23 %) were observed in DMS6h-FA complexes. The FA unsaturation degree induced little effect on the RS content and long-range structural order of the complexes. [ABSTRACT FROM AUTHOR]

This study investigated the use of cricket flour in frankfurters as a meat replacer and its impact on nutritional, technological, structural, and sensory characteristics. Four treatments were prepared with different concentrations of cricket flour (Control, CF2.5, CF5.0, and CF7.5). There was a significantly high protein content in treatments with cricket flour addition, but without change in the fat content. The CF7.5 treatment showed significantly high SFA and PUFA contents, but there was no significant impact on MUFA content, compared with control treatment. Cricket flour significantly improved the contents of zinc, calcium, and manganese but not that of sodium. The processing loss of reformulated frankfurters was significantly reduced. Reformulated frankfurters were brownish in color compared with the control, which affected the sensory scores of those treatments. No effect on the structural characteristics of frankfurters were observed. The CF2.5 treatment appeared to be the best alternative for using edible insects in frankfurters. • Three levels of meat replacement by cricket flour (2.5%, 5.0%, and 7.5%). • High protein content in frankfurters with cricket flour addition. • Lower processing loss in frankfurters with cricket flour addition. • Frankfurters with cricket flour addition were brownish in color. • The 2.5% of meat replacement with cricket flour appeared to be the best alternative. [ABSTRACT FROM AUTHOR]