State-dependent binding of cholesterol and an anionic lipid to the muscle-type Torpedo nicotinic acetylcholine receptor.

The ability of the Torpedo nicotinic acetylcholine receptor (nAChR) to undergo agonist-induced conformational transitions requires the presence of cholesterol and/or anionic lipids. Here we use recently solved structures along with multiscale molecular dynamics simulations to examine lipid binding to the nAChR in bilayers that have defined effects on nAChR function. We examine how phosphatidic acid and cholesterol, lipids that support conformational transitions, individually compete for binding with phosphatidylcholine, a lipid that does not. We also examine how the two lipids work synergistically to stabilize an agonist-responsive nAChR. We identify rapidly exchanging lipid binding sites, including both phospholipid sites with a high affinity for phosphatidic acid and promiscuous cholesterol binding sites in the grooves between adjacent transmembrane α-helices. A high affinity cholesterol site is confirmed in the inner leaflet framed by a key tryptophan residue on the MX α-helix. Our data provide insight into the dynamic nature of lipid-nAChR interactions and set the stage for a detailed understanding of the mechanisms by which lipids facilitate nAChR function at the neuromuscular junction.

Phospholipid Complex Formulation Technology for Improved Drug Delivery in Oncological Settings: a Comprehensive Review.

Addressing poor solubility and permeability issues associated with synthetic drugs and naturally occurring active compounds is crucial for improving bioavailability. This review explores the potential of phospholipid complex formulation technology to overcome these challenges. Phospholipids, as endogenous molecules, offer a viable solution, with drugs complexed with phospholipids demonstrating a similar absorption mechanism. The non-toxic and biodegradable nature of the phospholipid complex positions it as an ideal candidate for drug delivery. This article provides a comprehensive exploration of the mechanisms underlying phospholipid complexes. Special emphasis is placed on the solvent evaporation method, with meticulous scrutiny of formulation aspects such as the phospholipid ratio to the drug and solvent. Characterization techniques are employed to understand structural and functional attributes. Highlighting the adaptability of the phospholipid complex, the review discusses the loading of various nanoformulations and emulsion systems. These strategies aim to enhance drug delivery and efficacy in various malignancies, including breast, liver, lung, cervical, and pancreatic cancers. The broader application of the drug phospholipid complex is showcased, emphasizing its adaptability in diverse oncological settings. The review not only explores the mechanisms and formulation aspects of phospholipid complexes but also provides an overview of key clinical studies and patents. These insights contribute to the intellectual and translational advancements in drug phospholipid complexes.

Dehydration of Lipid Membranes Drives Redistribution of Cholesterol Between Lateral Domains.

Cholesterol-rich lipid rafts are found to facilitate membrane fusion, central to processes like viral entry, fertilization, and neurotransmitter release. While the fusion process involves local, transient membrane dehydration, the impact of reduced hydration on cholesterol's structural organization in biological membranes remains unclear. Here, we employ confocal fluorescence microscopy and atomistic molecular dynamics simulations to investigate cholesterol behavior in phase-separated lipid bilayers under controlled hydration. We unveiled that dehydration prompts cholesterol release from raft-like domains into the surrounding fluid phase. Unsaturated phospholipids undergo more significant dehydration-induced structural changes and lose more hydrogen bonds with water than sphingomyelin. The results suggest that cholesterol redistribution is driven by the equalization of biophysical properties between phases and the need to satisfy lipid hydrogen bonds. This underscores the role of cholesterol-phospholipid-water interplay in governing cholesterol affinity for a specific lipid type, providing a new perspective on the regulatory role of cell membrane heterogeneity during membrane fusion.

Nuclear Phospholipids and Signaling: An Update of the Story.

In the last three decades, the presence of phospholipids in the nucleus has been shown and thoroughly investigated. A considerable amount of interest has been raised about nuclear inositol lipids, mainly because of their role in signaling acting. Here, we review the main issues of nuclear phospholipid localization and the role of nuclear inositol lipids and their related enzymes in cellular signaling, both in physiological and pathological conditions.

Paraburkholderia translucens sp. nov. and Paraburkholderia sejongensis sp. nov., isolated from grassland soil and showing plant growth promoting potential.

Two Gram-negative bacterial strains designated MMS20-SJTN17T and MMS20-SJTR3T were isolated from a grassland soil sample, and taxonomically characterized using a polyphasic approach. The 16S rRNA gene sequence analysis indicates that both strains belong to the genus Paraburkholderia of the class Betaproteobacteria, with strain MMS20-SJTN17T being mostly related to Paraburkholderia sprentiae WSM5005T (96.45 % sequence similarity) and strain MMS20-SJTR3T to Paraburkholderia tuberum STM678T (98.59 % sequence similarity). MMS20-SJTN17T could grow at 15-40 °C (optimum, 25-30 °C) and at pH 6.0-8.0 (optimum, pH 6.0-7.0), whereas MMS20-SJTR3T could grow at 10-40 °C (optimum, 30-37 °C) and at pH 6.0-8.0 (optimum, pH 6.0). Both strains tolerated up to 1 % (w/v) NaCl (optimum, 0 %). The major fatty acids of MMS20-SJTN17T were C16 : 0 and C19 : 0 cyclo ω8c, and those of MMS20-SJTR3T were C17 : 0 cyclo and a summed feature comprising C18 : 1 ω7c and/or C18 : 1 ω6c. The major isoprenoid quinone of both strains was ubiquinone-8 and the diagnostic polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Regarding plant growth promoting potential, both strains were capable of producing indole acetic acid, siderophore and 1-aminocyclopropane-1-carboxylic acid deaminase, and also showed phosphate-solubilizing activity. A genome-based comparison using orthologous average nucleotide identity and digital DNA-DNA hybridization values indicates that strain MMS20-SJTN17T shares highest relatedness with Paraburkholderia monticola JC2948T and MMS20-SJTR3T with Paraburkholderia antibiotica G-4-1-8T, with values clearly below the cutoffs for species distinction. Examination of biosynthetic gene clusters responsible for secondary metabolite production reveals unique characteristics distinguishing each strain from closely related Paraburkholderia species. On the basis of genotypic, phenotypic, chemotaxonomic and phylogenomic data, each strain should be classified as a novel species of the genus Paraburkholderia, for which the names Paraburkholderia translucens sp. nov. (=MMS20-SJTN17T=LMG 32366T=KCTC 82783T) and Paraburkholderia sejongensis sp. nov. (=MMS20-SJTR3T=LMG 32367T=KCTC 82784T) are proposed.

Ruixingdingia sedimenti gen. nov., sp. nov., a novel taxon within the family Paracoccaceae isolated from sediment of Qiantang River.

A Gram-stain-negative bacterium, designated LG-4T, was isolated from sediment of Qiantang River in Zhejiang Province, PR China. Cells were strictly aerobic, non-spore-forming, non-motile and short-rod-shaped (1.0-1.2 µm long and 0.7-0.8 µm wide). Growth occurred at 15-42 °C (optimum, 30 °C), at pH 5.0-9.0 (pH 7.0) and at 0-2.0 % (w/v) NaCl (optimum, 0.5 % NaCl). Strain LG-4T showed 95.75-96.90 % 16S rRNA gene sequence similarity to various type strains of the genera Tabrizicola, Pseudotabrizicola, Phaeovulum, Rhodobacter and Wagnerdoeblera of the family Paracoccaceae, and the most closely related strain was Tabrizicola soli ZQBWT (96.90 % similarity). The phylogenomic tree showed that strain LG-4T clustered in the family Paracoccaceae and was positioned outside of the clade composed of the genera Wagnerdoeblera and Falsigemmobacter. The average nucleotide identity and digital DNA-DNA hybridization values between strain LG-4T and the related type strains were in the range of 74.19-77.56 % and 16.70-25.80 %, respectively. The average amino acid identity (AAI) values between strain LG-4T and related type strains of the family Paracoccaceae were 60.94-69.73 %, which are below the genus boundary (70 %). The evolutionary distance (ED) values between LG-4T and the related genera of the family Paracoccaceae were 0.21-0.34, which are within the recommended standard (≥0.21-0.23) for defining a novel genus in the family Paracoccaceae. The predominant cellular fatty acids were C18 : 1 ω7c, C19 : 0 cyclo ω8c, C18 : 0 and C16 : 0, the isoprenoid quinone was Q-10, and the major polar lipids were phospholipid, phosphatidylglycerol, phosphatidylcholine, aminolipid and two unknown polar lipids. The genome size was 4.7 Mb with 68.6 mol% G+C content. On the basis of distinct phylogenetic relationships, low AAI values and high ED values, and differential phenotypic, physiological and biochemical characteristics, strain LG-4T represents a novel species of a new genus in the family Paracoccaceae, for which the name Ruixingdingia sedimenti gen. nov., sp. nov. is proposed. The type strain is LG-4T (=MCCC 1K08849T=KCTC 8136T).

Phospholipids Differentially Regulate Ca2+ Binding to Synaptotagmin-1.

Synaptotagmin-1 (Syt-1) is a calcium sensing protein that is resident in synaptic vesicles. It is well established that Syt-1 is essential for fast and synchronous neurotransmitter release. However, the role of Ca2+ and phospholipid binding in the function of Syt-1, and ultimately in neurotransmitter release, is unclear. Here, we investigate the binding of Ca2+ to Syt-1, first in the absence of lipids, using native mass spectrometry to evaluate individual binding affinities. Syt-1 binds to one Ca2+ with a KD ∼ 45 µM. Each subsequent binding affinity (n ≥ 2) is successively unfavorable. Given that Syt-1 has been reported to bind anionic phospholipids to modulate the Ca2+ binding affinity, we explored the extent that Ca2+ binding was mediated by selected anionic phospholipid binding. We found that phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and dioleoylphosphatidylserine (DOPS) positively modulated Ca2+ binding. However, the extent of Syt-1 binding to phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) was reduced with increasing [Ca2+]. Overall, we find that specific lipids differentially modulate Ca2+ binding. Given that these lipids are enriched in different subcellular compartments and therefore may interact with Syt-1 at different stages of the synaptic vesicle cycle, we propose a regulatory mechanism involving Syt-1, Ca2+, and anionic phospholipids that may also control some aspects of vesicular exocytosis.

Chelativorans salis sp. nov., a slightly halophilic bacterium isolated from an enrichment system with saline lake sediment.

A Gram-stain-negative, non-motile, and slightly halophilic alphaproteobacterium, designated strain EGI FJ00035T, was isolated from enrichment sediment samples of a saline lake in Xinjiang Uygur Autonomous Region, PR China. The taxonomic position of the isolate was determined using the polyphasic taxonomic and phylogenomic analyses. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain EGI FJ00035T formed a distinct clade with 'Chelativorans alearense' UJN715 and 'Chelativorans xinjiangense' lm93 with sequence similarities of 98.44 and 98.22 %, respectively, while sharing less than 96.7 % with other valid type strains. The novel isolate could be distinguished from other species of the genus Chelativorans by its distinct phenotypic, physiological, and genotypic characteristics. Optimal growth of strain EGI FJ00035T occurred on marine agar 2216 at pH 7.0 and 30 °C. The major respiratory quinone was Q-10, while the major fatty acids (>5 %) were C19 : 0 cyclo ω8c, summed feature 8 (C17 : 1 ω6c and/or C17 : 1 ω7c), C16 : 0, C18 : 0, and iso-C17 : 0. The detected polar lipids included diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, unidentified aminophospholipids, unidentified glycolipids, and an unidentified lipid. Based on its genome sequence, the G+C content of strain EGI FJ00035T was 63.2 mol%. The average nucleotide identity, average amino acid identity, and digital DNA-DNA hybridization values of strain EGI FJ00035T against related members of the genus Chelativorans were below the thresholds for delineation of a novel species. According our polyphasic taxonomic data, strain EGI FJ00035T represents a new species of the genus Chelativorans, for which the name Chelativorans salis sp. nov. is proposed. The type strain of the proposed novel isolate is EGI FJ00035T (=KCTC 92251T=CGMCC 1.19480T).

Massilia luteola sp. nov., a novel indole-producing and cellulose-degrading bacterium isolated from soil.

A Gram-stain-negative, rod-shaped, indole-producing, and cellulose-degrading bacterial strain, designated NEAU-G-C5T, was isolated from soil collected from a forest in Dali city, Yunnan province, south China. 16S rRNA gene sequence analysis showed that strain NEAU-G-C5T was assigned to the genus Massilia and showed high sequence similarities to Massilia phosphatilytica 12-OD1T (98.32 %) and Massilia putida 6 NM-7T (98.41 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NEAU-G-C5T formed a lineage related to M. phosphatilytica 12-OD1T and M. putida 6 NM-7T. The major fatty acids of the strain were C16 : 0, C16 : 1 ω7c, and C17 : 0 cyclo. The respiratory quinone was Q-8. The polar lipid profile of the strain showed the presence of diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. In addition, the average nucleotide identity values between strain NEAU-G-C5T and its reference strains M. phosphatilytica 12-OD1T, M. putida 6 NM-7T, M. norwichensis NS9T, and M. kyonggiensis TSA1T were 89.7, 88.2, 81.3, and 88.0 %, respectively, and the levels of digital DNA-DNA hybridization between them were found to be 58.5 % (54.9-62.0 %), 53.2 % (49.8-56.7 %), 31.9 % (28.6-35.5 %), and 57.7 % (54.1-61.2 %), respectively, which were lower than the accepted threshold values of 95-96 % and 70 %, respectively. The DNA G+C content of strain NEAU-G-C5T was 66.5 mol%. The strain could produce indoleacetic acid and cellulase. On the basis of the phenotypic, genotypic, and chemotaxonomic characteristics, we conclude that strain NEAU-G-C5T represents a novel species of the genus Massilia, for which the name Massilia luteola sp. nov. is proposed. The type strain is NEAU-G-C5T (=MCCC 1K08668T=KCTC 8080T).

Saccharopolyspora ipomoeae sp. nov., an Actinomycete Isolated from Sweet Potato Field Soils.

During the course of the isolation of actinobacteria from sweet potato field soils collected from Phra Nakhon Si Ayutthaya province of Thailand, strain TS4A08T was isolated and subjected to a polyphasic taxonomic approach. The 16S rRNA gene sequence analysis of strain TS4A08T revealed that it is closely related to the type strains of Saccharopolyspora aridisoli, and Saccharopolyspora endophytica with 98.7%, and 98.6% similarity, respectively. However, phylogenetic analyses using 16S rRNA gene and genome sequences indicated that strain TS4A08T clustered with Saccharopolyspora flava AS4.1520T (98.2% similarity), well-supported by bootstrap values, and formed distinct line from the two closest strains. The average nucleotide identity (ANI) values and digital DNA-DNA hybridization (dDDH) values between the genome sequences of strain TS4A08T and the closest type strains of S. aridisoli, S. endophytica, and S. flava, were 86.1-93.2% and 33.1-49.6%, respectively, which were less than the threshold for the species delineation. The genome size and the DNA G + C content of strain TS4A08T were 6.6 Mbp and 70.5%, respectively. The strain grew well at 25-37 °C, pH range of 7-9, and NaCl concentration of 0-5% (w/v). Whole-cell hydrolysates contained meso-diaminopimelic acid. The major fatty acids were iso-C16:0, anteiso-C17:0, and iso-C15:0. Strain TS4A08T exhibited phosphatidylcholine in its polar lipid profile, with MK-9(H4) being the predominant isoprenologue. The strain exhibits typical chemotaxonomic properties of the genus Saccharopolyspora, including arabinose, galactose, and ribose as whole-cell sugars. Strain TS4A08T represents a novel species within the genus Saccharopolyspora, for which the name Saccharopolyspora ipomoeae sp. nov. is proposed. The type strain is TS4A08T (= TBRC 17271T = NBRC 115967T).

Investigating the causal associations between metabolic biomarkers and the risk of kidney cancer.

Metabolic reprogramming plays an important role in kidney cancer. We aim to investigate the causal effect of 249 metabolic biomarkers on kidney cancer from population-based data. This study extracts data from previous genome wide association studies with large sample size. The primary endpoint is random-effect inverse variance weighted (IVW). After completing 249 times of two-sample Mendelian randomization analysis, those significant metabolites are included for further sensitivity analysis. According to a strict Bonferrion-corrected level (P < 2e-04), we only find two metabolites that are causally associated with renal cancer. They are lactate (OR:3.25, 95% CI: 1.84-5.76, P = 5.08e-05) and phospholipids to total lipids ratio in large LDL (low density lipoprotein) (OR: 0.63, 95% CI: 0.50-0.80, P = 1.39e-04). The results are stable through all the sensitivity analysis. The results emphasize the central role of lactate in kidney tumorigenesis and provide novel insights into possible mechanism how phospholipids could affect kidney tumorigenesis.

The novel molecular mechanism of pulmonary fibrosis: insight into lipid metabolism from reanalysis of single-cell RNA-seq databases.

Pulmonary fibrosis (PF) is a severe pulmonary disease with limited available therapeutic choices. Recent evidence increasingly points to abnormal lipid metabolism as a critical factor in PF pathogenesis. Our latest research identifies the dysregulation of low-density lipoprotein (LDL) is a new risk factor for PF, contributing to alveolar epithelial and endothelial cell damage, and fibroblast activation. In this study, we first integrative summarize the published literature about lipid metabolite changes found in PF, including phospholipids, glycolipids, steroids, fatty acids, triglycerides, and lipoproteins. We then reanalyze two single-cell RNA-sequencing (scRNA-seq) datasets of PF, and the corresponding lipid metabolomic genes responsible for these lipids' biosynthesis, catabolism, transport, and modification processes are uncovered. Intriguingly, we found that macrophage is the most active cell type in lipid metabolism, with almost all lipid metabolic genes being altered in macrophages of PF. In type 2 alveolar epithelial cells, lipid metabolic differentially expressed genes (DEGs) are primarily associated with the cytidine diphosphate diacylglycerol pathway, cholesterol metabolism, and triglyceride synthesis. Endothelial cells are partly responsible for sphingomyelin, phosphatidylcholine, and phosphatidylethanolamines reprogramming as their metabolic genes are dysregulated in PF. Fibroblasts may contribute to abnormal cholesterol, phosphatidylcholine, and phosphatidylethanolamine metabolism in PF. Therefore, the reprogrammed lipid profiles in PF may be attributed to the aberrant expression of lipid metabolic genes in different cell types. Taken together, these insights underscore the potential of targeting lipid metabolism in developing innovative therapeutic strategies, potentially leading to extended overall survival in individuals affected by PF.

Membrane phospholipids activate the inflammatory response in macrophages by various mechanisms.

Exosomes, which are small membrane-encapsulated particles derived from all cell types, are emerging as important mechanisms for intercellular communication. In addition, exosomes are currently envisioned as potential carriers for the delivery of drugs to target tissues. The natural population of exosomes is very variable due to the limited amount of cargo components present in these small vesicles. Consequently, common components of exosomes may play a role in their function. We have proposed that membrane phospholipids could be a common denominator in the effect of exosomes on cellular functions. In this regard, we have previously shown that liposomes made of phosphatidylcholine (PC) or phosphatidylserine (PS) induced a robust alteration of macrophage (Mϕ) gene expression. We herewith report that these two phospholipids modulate gene expression in Mϕs by different mechanisms. PS alters cellular responses by the interaction with surface receptors, particularly CD36. In contrast, PC is captured by a receptor-independent process and likely triggers an activity within endocytic vesicles. Despite this difference in the capture mechanisms, both lipids mounted similar gene expression responses. This investigation suggests that multiple mechanisms mediated by membrane phospholipids could be participating in the alteration of cellular functions by exosomes.

Sphingomonas lacusdianchii sp. nov., an attached bacterium inhibited by metabolites from its symbiotic cyanobacterium.

An alpha-proteobacterial strain JXJ CY 53 T was isolated from the cyanosphere of Microcystis sp. FACHB-905 (MF-905) collected from Lake Dianchi, China. JXJ CY 53 T was observed to be an aerobic, Gram-stain-negative, oval shaped, and mucus-secreting bacterium. It had C18:1ω7c and C16:0 as the major cellular fatty acids, Q-10 as the predominant ubiquinone, and sphingoglycolipid, diphosphatidylglycerol, phosphatidylcholine, and phosphatidylmethylethanolamine as the polar lipids. The G + C content of DNA was 65.85%. The bacterium had 16S rRNA gene sequence identities of 98.9% and 98.7% with Sphingomonas panni DSM 15761 T and Sphingomonas hankookensis KCTC 22579 T, respectively, while less than 97.4% identities with other members of the genus. Further taxonomic analysis indicated that JXJ CY 53 T represented a new member of Sphingomonas, and the species epithet was proposed as Sphingomonas lacusdianchii sp. nov. (type strain JXJ CY 53 T = KCTC 72813 T = CGMCC 1.17657 T). JXJ CY 53 T promoted the growth of MF-905 by providing bio-available phosphorus and nitrogen, plant hormones, vitamins, and carotenoids. It could modulate the relative abundances of nonculturable bacteria associated with MF-905 and influence the interactions of MF-905 and other bacteria isolated from the cyanobacterium, in addition to microcystin production characteristics. Meanwhile, MF-905 could provide JXJ CY 53 T dissolved organic carbon for growth, and control the growth of JXJ CY 53 T by secreting specific chemicals other than microcystins. Overall, these results suggest that the interactions between Microcystis and its attached bacteria are complex and dynamic, and may influence the growth characteristics of the cyanobacterium. This study provided new ideas to understand the interactions between Microcystis and its attached bacteria. KEY POINTS: • A novel bacterium (JXJCY 53 T) was isolated from the cyanosphere of Microcystis sp. FACHB-905 (MF-905) • JXJCY 53 T modulated the growth and microcystin production of MF-905 • MF-905 could control the attached bacteria by specific chemicals other than microcystins (MCs).

Exploring Skin Wound Healing Models and the Impact of Natural Lipids on the Healing Process.

Cutaneous wound healing is a complex biological process involving a series of well-coordinated events aimed at restoring skin integrity and function. Various experimental models have been developed to study the mechanisms underlying skin wound repair and to evaluate potential therapeutic interventions. This review explores the diverse array of skin wound healing models utilized in research, ranging from rodent excisional wounds to advanced tissue engineering constructs and microfluidic platforms. More importantly, the influence of lipids on the wound healing process is examined, emphasizing their role in enhancing barrier function restoration, modulating inflammation, promoting cell proliferation, and promoting remodeling. Lipids, such as phospholipids, sphingolipids, and ceramides, play crucial roles in membrane structure, cell signaling, and tissue repair. Understanding the interplay between lipids and the wound microenvironment provides valuable insights into the development of novel therapeutic strategies for promoting efficient wound healing and tissue regeneration. This review highlights the significance of investigating skin wound healing models and elucidating the intricate involvement of lipids in the healing process, offering potential avenues for improving clinical outcomes in wound management.

A Cross-Sectional Pilot Study on Association of Ready-to-Eat and Processed Food Intakes with Metabolic Factors, Serum Trans Fat and Phospholipid Fatty Acid Compositions in Healthy Japanese Adults.

Frequently consuming processed and ready-to-eat (RTE) foods is regarded as unhealthy, but evidence on the relationships with circulating metabolic parameters is lacking. Japanese residents of a metropolitan area, 20 to 50 years of age, were studied in terms of anthropometric and biochemical parameters, including circulating trans fat and serum phospholipid fatty acid levels. Processed foods, except drinks and dairy items, were categorized according to requirements for additional ingredients and cooking before eating. Processed and RTE foods were divided according to fat and/or oil content into non-fatty or fatty foods. The participants were grouped into tertiles based on the energy percent (En%) derived from fatty-RTE foods. Fatty-RTE En% showed negative associations with fish, soybean and soybean products, dairy, eggs, vegetables, seaweed/mushrooms/konjac, fruit and non-oily seasonings reflecting lower dietary fiber, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and mineral and vitamin intakes, while the associations with fat/oil, confectionaries, and sweet beverages were positive. Fatty-RTE En% consumption was positively associated with alkaline phosphatase, leucine aminopeptidase, direct bilirubin, elaidic acid, and C18:2 but inversely associated with HDL cholesterol, C15:0, C17:0, EPA, and DHA. A higher fatty-RTE food intake was suggested to contribute to unbalanced nutrient intakes, as reflected in lipid metabolic parameters. Further large-scale studies are needed to evaluate the quality and impacts of RTE foods.

CoPoP liposomes displaying stabilized clade C HIV-1 Env elicit tier 2 multiclade neutralization in rabbits.

One of the strategies towards an effective HIV-1 vaccine is to elicit broadly neutralizing antibody responses that target the high HIV-1 Env diversity. Here, we present an HIV-1 vaccine candidate that consists of cobalt porphyrin-phospholipid (CoPoP) liposomes decorated with repaired and stabilized clade C HIV-1 Env trimers in a prefusion conformation. These particles exhibit high HIV-1 Env trimer decoration, serum stability and bind broadly neutralizing antibodies. Three sequential immunizations of female rabbits with CoPoP liposomes displaying a different clade C HIV-1 gp140 trimer at each dosing generate high HIV-1 Env-specific antibody responses. Additionally, serum neutralization is detectable against 18 of 20 multiclade tier 2 HIV-1 strains. Furthermore, the peak antibody titers induced by CoPoP liposomes can be recalled by subsequent heterologous immunization with Ad26-encoded membrane-bound stabilized Env antigens. Hence, a CoPoP liposome-based HIV-1 vaccine that can generate cross-clade neutralizing antibody immunity could potentially be a component of an efficacious HIV-1 vaccine.

Lipid exchange of apolipoprotein A-I amyloidogenic variants in reconstituted high-density lipoprotein with artificial membranes.

High-density lipoproteins (HDLs) are responsible for removing cholesterol from arterial walls, through a process known as reverse cholesterol transport. The main protein in HDL, apolipoprotein A-I (ApoA-I), is essential to this process, and changes in its sequence significantly alter HDL structure and functions. ApoA-I amyloidogenic variants, associated with a particular hereditary degenerative disease, are particularly effective at facilitating cholesterol removal, thus protecting carriers from cardiovascular disease. Thus, it is conceivable that reconstituted HDL (rHDL) formulations containing ApoA-I proteins with functional/structural features similar to those of amyloidogenic variants hold potential as a promising therapeutic approach. Here we explored the effect of protein cargo and lipid composition on the function of rHDL containing one of the ApoA-I amyloidogenic variants G26R or L174S by Fourier transformed infrared spectroscopy and neutron reflectometry. Moreover, small-angle x-ray scattering uncovered the structural and functional differences between rHDL particles, which could help to comprehend higher cholesterol efflux activity and apparent lower phospholipid (PL) affinity. Our findings indicate distinct trends in lipid exchange (removal vs. deposition) capacities of various rHDL particles, with the rHDL containing the ApoA-I amyloidogenic variants showing a markedly lower ability to remove lipids from artificial membranes compared to the rHDL containing the native protein. This effect strongly depends on the level of PL unsaturation and on the particles' ultrastructure. The study highlights the importance of the protein cargo, along with lipid composition, in shaping rHDL structure, contributing to our understanding of lipid-protein interactions and their behavior.

Marinobacter qingdaonensis sp. nov., a moderately halotolerant bacterium isolated from intertidal sediment.

A Gram-stain-negative, aerobic, rod-shaped and halotolerant bacterium, designated as strain ASW11-75T, was isolated from intertidal sediments in Qingdao, PR China, and identified using a polyphasic taxonomic approach. Growth of strain ASW11-75T occurred at 10-45 °C (optimum, 37 °C), pH 6.5-9.0 (optimum, pH 8.0) and 0.5-18.0 % NaCl concentrations (optimum, 2.5 %). Phylogenetic analyses based on 16S rRNA gene sequences and 1179 single-copy orthologous clusters indicated that strain ASW11-75T is affiliated with the genus Marinobacter. Strain ASW11-75T showed highest 16S rRNA gene sequence similarity to 'Marinobacter arenosus' CAU 1620T (98.5 %). The digital DNA-DNA hybridization and average nucleotide identity values between strain ASW11-75T and its closely related strains (Marinobacter salarius R9SW1T, Marinobacter similis A3d10T, 'Marinobacter arenosus' CAU 1620T, Marinobacter sediminum R65T, Marinobacter salinus Hb8T, Marinobacter alexandrii LZ-8T and Marinobacter nauticus ATCC 49840T) were 19.8-24.5 % and 76.6-80.7 %, respectively. The predominant cellular fatty acids were C16 : 0, C18 : 1 ω9c and C16 : 0 N alcohol. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified aminophospholipid and two unidentified lipids. The major isoprenoid quinone was ubiquinone-9. The genomic DNA G+C content was 62.2 mol%. Based on genomic and gene function analysis, strain ASW11-75T had lower protein isoelectric points with higher ratios of acidic residues to basic residues and possessed genes related to ion transport and organic osmoprotectant uptake, implying its potential tolerance to salt. The results of polyphasic characterization indicated strain ASW11-75T represents a novel Marinobacter species, for which the name Marinobacter qingdaonensis sp. nov. with the type strain ASW11-75T is proposed. The type strain is ASW11-75T (=KCTC 82497T=MCCC 1K05587T).

Oxidized phospholipid POVPC contributes to vascular calcification by triggering ferroptosis of vascular smooth muscle cells.

Vascular calcification is an actively regulated biological process resembling bone formation, and osteogenic differentiation of vascular smooth muscle cells (VSMCs) plays a crucial role in this process. 1-Palmitoyl-2-(5'-oxo-valeroyl)-sn-glycero-3-phosphocholine (POVPC), an oxidized phospholipid, is found in atherosclerotic plaques and has been shown to induce oxidative stress. However, the effects of POVPC on osteogenic differentiation and calcification of VSMCs have yet to be studied. In the present study, we investigated the role of POVPC in vascular calcification using in vitro and ex vivo models. POVPC increased mineralization of VSMCs and arterial rings, as shown by alizarin red staining. In addition, POVPC treatment increased expression of osteogenic markers Runx2 and BMP2, indicating that POVPC promotes osteogenic transition of VSMCs. Moreover, POVPC increased oxidative stress and impaired mitochondria function of VSMCs, as shown by increased ROS levels, impairment of mitochondrial membrane potential, and decreased ATP levels. Notably, ferroptosis triggered by POVPC was confirmed by increased levels of intracellular ROS, lipid ROS, and MDA, which were decreased by ferrostatin-1, a ferroptosis inhibitor. Furthermore, ferrostatin-1 attenuated POVPC-induced calcification of VSMCs. Taken together, our study for the first time demonstrates that POVPC promotes vascular calcification via activation of VSMC ferroptosis. Reducing the levels of POVPC or inhibiting ferroptosis might provide a novel strategy to treat vascular calcification.