Despite longstanding excitement and progress toward understanding liquid-liquid phase separation in natural and artificial membranes, fundamental questions have persisted about which molecules are required for this phenomenon. Except in extraordinary circumstances, the smallest number of components that has produced large-scale, liquid-liquid phase separation in bilayers has stubbornly remained at three: a sterol, a phospholipid with ordered chains, and a phospholipid with disordered chains. This requirement of three components is puzzling because only two components are required for liquid-liquid phase separation in lipid monolayers, which resemble half of a bilayer. Inspired by reports that sterols interact closely with lipids with ordered chains, we tested whether phase separation would occur in bilayers in which a sterol and lipid were replaced by a single, joined sterol-lipid. By evaluating a panel of sterol-lipids, some of which are present in bacteria, we found a minimal bilayer of only two components (PChemsPC and diPhyPC) that robustly demixes into micron-scale, liquid phases. It suggests an additional role for sterol-lipids in nature, and it reveals a membrane in which tie-lines (and, therefore, the lipid composition of each phase) are straightforward to determine and will be consistent across multiple laboratories.

Suspended membranes of monatomic graphene exhibit great potential for applications in electronic and nanoelectromechanical devices. In this work, a \"hot and dry\" transfer process is demonstrated to address the fabrication and patterning challenges of large-area graphene membranes on top of closed, sealed cavities. Here, \"hot\" refers to the use of high temperature during transfer, promoting the adhesion. Additionally, \"dry\" refers to the absence of liquids when graphene and target substrate are brought into contact. The method leads to higher yields of intact suspended monolayer chemical vapor deposition (CVD) graphene and artificially stacked double-layer CVD graphene membranes than previously reported. The yield evaluation is performed using neural-network-based object detection in scanning electron microscopy (SEM) images, ascertaining high yields of intact membranes with large statistical accuracy. The suspended membranes are examined by Raman tomography and atomic force microscopy (AFM). The method is verified by applying the suspended graphene devices as piezoresistive pressure sensors. Our technology advances the application of suspended graphene membranes and can be extended to other two-dimensional materials.

When submitted to environmental stresses, bacteria can modulate its fatty acid composition of membrane phospholipids in order to optimize membrane fluidity. Characterization of bacterial membrane fatty acid profiles is thus an interesting indicator of cellular physiological state. The methodology described here aims to improve the recovering of biofilm cells for the characterization of their fatty acid profiles. The saponification reagent is directly applied on the whole biofilm before the removal of cells from the inert surface. In this way, maximum of the cells and their fatty acids can be recovered from the deepest layers of the biofilm.

BACKGROUND: The assessment of the hard and soft tissue conditions is part of the overall dental treatments.
OBJECTIVE: In this study, we investigated nano curcumin-containing membranes to improve the quality of the hard and soft tissues in the extracted tooth area as a clinical trial study.
METHODS: After the patient was selected following the inclusion and exclusion criteria, the patients who had teeth extracted from both sides of the mouth (split mouth) on the side of the intervention received a membrane containing nanocurcumin, and on the control side, no material was placed in the socket. For data analysis, SPSS software version 24 was used. A significance threshold was deemed to be less than 0.05 in terms of probability.
RESULTS: Two months after tooth extraction, during implant placement, the average gingival thickness on the \"intervention side,\" was 3.1±0.34 mm, while the average gingival thickness on the \"control side\" was 2.6±0.42 mm. Then, the membrane could improve the quality of soft tissue (P< 0.0001). As another outcome, the application of this membrane did not significantly affect bone repair in these patients compared to the control group (P = 0.72). However, the histology data revealed that the newly generated bone of the intervention group was seen close to the membrane, demonstrating the osteoconductive ability of the membrane.
CONCLUSIONS: Based on the obtained results, the newly developed membrane can be used to improve the quality of hard and soft tissues in the extracted tooth area. Nonetheless, more efforts in nanocurcumin dosage adjustment are needed for hard tissue regeneration in future studies.

Single-stranded, positive-sense RNA ((+)RNA) viruses replicate their genomes in virus-induced intracellular membrane compartments. (+)RNA viruses dedicate a significant part of their small genomes (a few thousands to a few tens of thousands of bases) to the generation of these compartments by encoding membrane-interacting proteins and/or protein domains. Noroviruses are a very diverse genus of (+)RNA viruses including human and animal pathogens. Human noroviruses are the major cause of acute gastroenteritis worldwide, with genogroup II genotype 4 (GII.4) noroviruses accounting for the vast majority of infections. Three viral proteins encoded in the N-terminus of the viral replication polyprotein direct intracellular membrane rearrangements associated with norovirus replication. Of these three, nonstructural protein 4 (NS4) seems to be the most important, although its exact functions in replication organelle formation are unknown. Here we produce, purify and characterize GII.4 NS4. AlphaFold modeling combined with experimental data refine and correct our previous crude structural model of NS4. Using simple artificial liposomes, we report an extensive characterization of the membrane properties of NS4. We find that NS4 self-assembles and thereby bridges liposomes together. Cryo-EM, NMR and membrane flotation show formation of several distinct NS4 assemblies, at least two of them bridging pairs of membranes together in different fashions. Noroviruses belong to (+)RNA viruses whose replication compartment is extruded from the target endomembrane and generates double-membrane vesicles. Our data establish that the 21-kDa GII.4 human norovirus NS4 can, in the absence of any other factor, recapitulate in tubo several features, including membrane apposition, that occur in such processes.

UNASSIGNED: Chitosan membranes with glycerol can function as an effective dispersing agent for different antibiotics or active ingredients that can be used in the treatment of diseases present in the oral cavity.
UNASSIGNED: The effects of the addition of glycerol on the mechanical, water absorption, swelling, pH, thickness, disintegration, rugosity, and antibacterial properties of chitosan-chlorhexidine- glycerol membranes were investigated in this study.
UNASSIGNED: Mechanical results indicated that chitosan membranes\' rugosity, strength, flexion, and thickness differed at loading 1, 3, 5, 10, 15, and 20% of glycerol (p < 0.05). The chitosan membranes\' rugosity, dissolution, strength, and pH results were significantly enhanced by the presence of glycerol at 3, 5, and 10% concentrations. In this investigation, the antimicrobial activity model used was the inhibition of Streptococcus mutans CDBB-B-1455 by chitosan-chlorhexidine membranes. It was observed that there was no change in inhibition with different concentrations of glycerol. The results suggest that chitosan-glycerol-chlorhexidine membranes may be a potential candidate for topical antiseptic application in buccal-dental disorders caused by S. mutans, such as caries, periodontal diseases, and oral squamous cell carcinoma, helping to prevent the development of serious conditions that can compromise human health.

Our interest in the design of heavy pnictogen-based Lewis acids for anion trafficking across biological membrane mimics has led us to investigate trivalent bismuthenium cations as chloride anion transporters. Here, we describe two chlorodiarylbismuthines, elaborated on a peri-substituted acenaphthene backbone and stabilized by an adjacent thio- or seleno-ether functionality that engages the bismuth center in a Ch→Bi interaction (Ch = chalcogen). These new derivatives are stable in aqueous environment and readiliy transport chloride anions across the membrane of phospholipid-based vesicles loaded with KCl. In addition to establishing the use of such motifs in anion transport, this investigation shows that the Lewis acidity, lipophilicity, and thus chloride transport properties depend on the nature of the chalcogen.

Lysophospholipid transporter LplT and acyltransferase Aas consist of a lysophospholipid-remodeling system ubiquitously found in gram-negative microorganisms. LplT flips lysophospholipids across the inner membrane, which are subsequently acylated by Aas on the cytoplasmic membrane surface. Our previous study showed that the proper functioning of this system is important to protecting E. coli from phospholipase-mediated host attack by maintaining the integrity of the bacterial cell envelope. However, the working mechanism of this system is still unclear. Herein, we report that LplT and Aas form a membrane protein complex in E. coli which allows these two enzymes to cooperate efficiently to move lysophospholipids across the bacterial membrane and catalyze their acylation. The direct interaction of LplT and Aas was demonstrated both in vivo and in vitro with a binding affinity of 2.3 μM. We found that a cytoplasmic loop of LplT adjacent to the exit of the substrate translocation pathway plays an important role in maintaining its interaction with Aas. Aas contains an acyl-acyl carrier protein synthase domain and an acyl-transferase domain. Its interaction with LplT is mediated exclusively by its transferase domain. Mutations within the three loops near the putative catalytic site of the transferase domain, respectively, disrupt its interaction with LplT and lysophospholipid acylation activity. These results support a hypothesis of the functional coupling mechanism, in which LplT directly interacts with the transferase domain of Aas for specific substrate membrane migration, providing synchronization of substrate translocation and biosynthetic events.

UNASSIGNED: Urea is a fertilizer widely used by farmers, especially vegetable farmers, due to its high nitrogen content, around 46 %. However, plants only use a small amount of nitrogen, a maximum of 35 %, while the remaining nitrogen is wasted and released into the environment. Undeniably, it causes increases production costs and environmental problems. A slow-release urea fertilizer (SRF) has been formulated to resolve these issues.
UNASSIGNED: In this study, the membrane was made of chitosan with several crosslinking agents such as Tripolyphosphate (TPP). In addition, calcium ion bonds are expected to increase the interaction with urea fertilizer through the encapsulation process.
UNASSIGNED: Our data showed that urea slow-release fertilizer (SRF) with the chitosan/TPP/Ca membrane, was successfully synthesized. This membrane has the characteristics of a thin white layer that is transparent. The physical and chemical characterization of SRF membranes with various coating membrane variations showed that the chitosan/TPP/Ca-urea membrane has Young\'s modulus of 7.75-22.05 N/mm2, swelling of 109.52-132.62 % and porosity of 0.756-1.06 %. Functional group analysis shows that several spectral changes indicate the presence of crosslinking process between the chitosan functional groups and TPP. The urea release results show that the membrane is released through a diffusion mechanism. Furthermore, SEM results show that these membranes have pores with various shapes and sizes.
UNASSIGNED: Based on the result, it can be concluded that chitosan membrane modification with the addition of TPP and calcium oxide provides improved membrane characteristic cs including degree of development, hydrophobicity, membrane stress, and nitrogen release on the membrane. This membrane shows is indicating suitability as a slow-release fertilizer.

Oleate hydratase (OhyA) is a bacterial peripheral membrane protein that catalyzes FAD-dependent water addition to membrane bilayer-embedded unsaturated fatty acids. The opportunistic pathogen Staphylococcus aureus uses OhyA to counteract the innate immune system and support colonization. Many Gram-positive and Gram-negative bacteria in the microbiome also encode OhyA. OhyA is a dimeric flavoenzyme whose carboxy terminus is identified as the membrane binding domain; however, understanding how OhyA binds to cellular membranes is not complete until the membrane-bound structure has been elucidated. All available OhyA structures depict the solution state of the protein outside its functional environment. Here, we employ liposomes to solve the cryo-electron microscopy structure of the functional unit: the OhyA•membrane complex. The protein maintains its structure upon membrane binding and slightly alters the curvature of the liposome surface. OhyA preferentially associates with 20-30 nm liposomes with multiple copies of OhyA dimers assembling on the liposome surface resulting in the formation of higher-order oligomers. Dimer assembly is cooperative and extends along a formed ridge of the liposome. We also solved an OhyA dimer of dimers structure that recapitulates the intermolecular interactions that stabilize the dimer assembly on the membrane bilayer as well as the crystal contacts in the lattice of the OhyA crystal structure. Our work enables visualization of the molecular trajectory of membrane binding for this important interfacial enzyme.