Linear Molecules Research Articles

Analysis of the Tomato Aspermy Virus Complete Genomes Suggests Reassortment in Russian Isolates from Chrysanthemum

Tomato aspermy virus (TAV, genus Cucumovirus from the family Bromoviridae) is one of the most common and harmful chrysanthemum viruses, causing severe flower distortion, size reduction and color breaking. Metatranscriptome sequencing of chrysanthemum plants of the Ribonette and Golden Standard cultivars from the collection of the Nikita Botanical Garden (Yalta, Republic of Crimea) generated TAV-related reads. The complete genomes of two Russian isolates of the virus were assembled from the reads obtained. This is the first report of full-length TAV genomes from Russia. Typically of cucumoviruses, the segmented TAV genome is represented by three single-stranded positive-sense linear RNA molecules with a length of 3412 (RNA1), 3097 (RNA2) and 2219 (RNA3) nucleotides. Five open reading frames (ORF) have been identified that encode replicase (ORF1), RNA-dependent RNA polymerase (ORF2a), silencing suppressor protein (OFR2b), movement protein (OFR3a) and the virus coat protein (ORF3b). The identity of the TAV genomes from the two chrysanthemum cultivars was 99.8% for all three viral RNAs, and with other TAV isolates from Genbank – 97.5–99.7 (RNA1), 93.8–99.8 (RNA2), and 89.3–99.3% (RNA3). Phylogenetic analysis showed that RNA1 and RNA3 of the Russian isolates were assigned to heterogeneous groups of TAV isolates found on various plant species in different regions of the world. At the same time, RNA2 clearly clustered with tomato isolates SKO20ST2 from Slovenia and PV-0220 from Bulgaria and, to a lesser extent, with the Iranian isolate Ker.Mah.P from petunia and the Chinese isolate Henan from chrysanthemum. The incongruence of phylogenetic trees reconstructed from different segments of the viral genome suggests pseudo-recombination (reassortment) in the Russian TAV isolates.

Photophysical properties of several multi-branched oligomers: An ultrafast excited state dynamics and quantum chemical calculation study

Multi-branched oligomers F1, F2 and F3 were investigated by spectroscopic experiments as well as quantum chemical calculations to elucidate the structure–property relationships and intramolecular charge transfer (ICT) characteristics of typical nonlinear optical materials. A better ICT property of F2 is obtained by replacing terminal electron donors with stronger electron-donating ability. The degree of ICT is effectively increased, which can be clearly seen from the frontier molecular orbitals contribution of central anthracene between HOMO and LUMO. The central group plays a major role in the direction as well as effective path of ICT process. In the X-shaped oligomers with anthracene as central group, ICT process takes place from terminal groups of [Formula: see text] position branches, to the central anthracene group. However, the electron distribution as well as the ICT of tri-branched oligomer F3 with triazine as central group is not symmetric. ICT process of F3 takes place from terminal triphenylamine groups to the central triazine and two fluorene groups at [Formula: see text] position branches. Y-shaped oligomer F3 has a longer lifetime of ICT state as well as a higher fluorescence quantum yield, which is consistent with the results of time-resolved fluorescence spectroscopy. Z-scan results show that the TPA cross-section value of F3 is 10.6 and 2.9 times higher than that of X-shaped F1 and F2. The dynamics curves of transient absorption spectroscopy also indicate that oligomer F3 structure has relatively stronger ICT properties. To verify the substituent effect, two linear molecules F4 and F5 were also calculated. The quantum chemical calculations result shows that the branches at positions 4 and 11 of the central anthracene group have little effect on the electron cloud distribution, and there are indeed significant differences in the contributions of branches at different positions. Our results may provide some reference for molecular design.

Controllable C2H2/CO2 inverse adsorption and separation in pillar-layered Zn-1,2,4-triazolate-dicarboxylate frameworks induced by the ligand aromaticity

Acetylene (C2H2) and carbon dioxide (CO2) both are linear molecules and the similarity in size and physical properties makes their separation very challenging. Compared to the C2H2-selective C2H2/CO2 separation, the inscrutable CO2-selective capture (also called inverse C2H2/CO2 separation) process is ideal as it enables one-step production of high-purity C2H2. Herein, we demonstrate the controllable C2H2/CO2 inverse adsorption and separation in a series of isomorphic Zn-1,2,4-triazolate-dicarboxylate pillar-layered frameworks (Zn-FA-TRZ, Zn-MUC-TRZ, and Zn-BDC-TRZ) based on the aromaticity modulation strategy. Compared with Zn-MUC-TRZ, the utilization of shorter FA linker only with one double bond leads to an intersection point between the isothermal adsorption curves. After the intersection points, Zn-FA-TRZ showed higher CO2 uptakes than C2H2 (thermodynamic inversion) and the intersection point moving towards the high-pressure region with the increasing temperature. When BDC involved, the enhanced ligand aromaticity enables a complete thermodynamic inversion for C2H2 and CO2 adsorption due to the much stronger interactions between the aromatic ring and CO2 molecules. The isosteric heats of adsorption for CO2 and C2H2 clearly support such inverse adsorption induced by the ligand aromaticity. Furthermore, the fixed-bed dynamic breakthrough experiments indicate that Zn-FA-TRZ and Zn-MUC-TRZ both have common C2H2-selective separation process, but Zn-BDC-TRZ adsorbent shows a prominent CO2-selective inverse C2H2/CO2 separation. Specially, with temperature increased, the inverse separation performance enhanced, and high purity C2H2 (>99.99 %) can be obtained via one-step separation from C2H2/CO2 (50/50) mixture at room temperature. Overall, inverse C2H2/CO2 separation was successfully achieved in pillar-layered metal–organic frameworks, which is helpful for the exploration of practical acetylene adsorbents.

Therapeutics and prophylactic efficacy of novel lytic Escherichia phage vB_EcoS_PJ16 against multidrug-resistant avian pathogenic E. coli using in vivo study.

Avian pathogenic Escherichia coli (APEC) is the causative agent of avian colibacillosis, which causes significant economic losses to the poultry industry. The growing resistance of bacteria to antibiotics is a major global public health concern. However, there is limited data on the efficacy of phage therapy in effectively controlling and treating APEC infections. In this study, a novel lytic Escherichia phage, vB_EcoS_PJ16, was isolated from poultry farm wastewater and characterized in both in vitro and in vivo conditions. Transmission electron microscopy analysis revealed the presence of an icosahedral head and a long non-contractile tail, classifying the phage under the Caudoviricetes class. Host range determination showed that Escherichia phage vB_EcoS_PJ16 exhibited lytic activity against multiple strains of pathogenic E. coli, while no significant signs of lysis for Klebsiella pneumoniae, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus. Biophysical characterization revealed that the isolated phage was sturdy, as it remained viable for up to 300days at temperatures of 30°C, 37°C, and 42°C and for up to 24h at pH 5 to 11, with only minor changes in titer. Kinetic analysis at multiplicity of infection (MOI) 0.1 showed a latency period of about 20min and a burst size of 26.5 phage particles per infected cell for phage vB_EcoS_PJ16. Whole genome sequencing unveiled that the phage vB_EcoS_PJ16 genome consists of a double-stranded linear DNA molecule with 57,756bp and a GC content of 43.58%. The Escherichia phage vB_EcoS_PJ16 genome consisted of 98 predicted putative ORFs, with no transfer RNA identified in the genome. Among these 98 genes, 34 genes were predicted to have known functions. A significant reduction in APEC viability was observed at MOI 100 during in vitro bacterial challenge tests conducted at different MOIs (0.01, 1, and 100). In vivo oral evaluation of the isolated phage to limit E. coli infections in day-old chicks indicated a decrease in mortality within both the therapeutic (20%) and prophylactic (30%) groups, when compared to the control group. The findings of this study contribute to our current knowledge of Escherichia phages and suggest a potentially effective role of phages in the therapeutic and prophylactic control of antibiotic-resistant APEC strains.

Triple Amplification Strategy of CHA-PER-DNAzyme for Ultrasensitive Detection of circRNA Associated with Hepatocellular Carcinoma.

Biological and clinical studies have indicated that aberrant expression of circMTO1 served as a crucial biomarker for the diagnosis and prognosis of hepatocellular carcinoma (HCC) patients as well as a potential therapeutic target. However, the detection of circRNAs currently faces challenges such as homologous linear RNA interference and low-expression abundance of certain circRNAs. Therefore, we developed a triple amplification method based on catalytic hairpin assembly (CHA) activation by back-splice junction (BSJ), resulting in CHA products that triggered primer exchange reaction to generate DNAzyme. Subsequently, DNAzyme cleaved the fluorescent reporter chain, enabling ultrasensitive detection of hepatocellular carcinoma-associated circMTO1 through the output fluorescence signal. The catalytic hairpin opening sequence within CHA specifically targeted the BSJ sequence in circRNA, thereby avoiding false positive signals observed in circRNA assays due to the recognition of homologous linear RNA molecules. Moreover, this triple amplification method facilitated sensitive detection of circRNA and addressed the issue of low-abundance expression levels associated with circMTO1 in HCC samples. Notably, our newly designed assay for detecting circRNA exhibited a linear range from 1 fM to 100 nM with a detection limit of 0.265 fM. Furthermore, it demonstrated excellent and consistent performance even within complex systems. Our proposed method enabled the specific and sensitive detection of circMTO1 in various cancer cells and blood samples from HCC patients, providing an innovative approach for investigating the role of circRNA in tumorigenesis and development while promoting its clinical application.

Plastid Nucleoids: Insights into Their Shape andDynamics.

Chloroplasts/plastids are unique organelles found in plant cells and some algae and are responsible for performing essential functions such as photosynthesis. The plastid genome, consisting of circular and linear DNA molecules, is packaged and organized into specialized structures called nucleoids. The composition and dynamics of these nucleoids have been the subject of intense research, as they are critical for proper plastid functions and development. In this mini-review, recent advances in understanding the organization and regulation of plastid nucleoids are overviewed, with a focus on the various proteins and factors that regulate the shape and dynamics of nucleoids, including DNA-binding proteins and membrane anchorage proteins. The dynamic nature of nucleoid organization, which is influenced by a variety of developmental cues and the cell cycle, is also examined.

Genome sequence of a Sobemovirus from the feces of Northern Pintail (Anas acuta).

Northern pintail (Anas acuta) is a migratory waterfowl that can transmit various viruses. The genome sequence of a Sobemovirus was determined using metagenomic sequencing from the feces of northern pintail (Anas acuta) in Xinjiang, northwest China. The virus possesses a linear RNA molecule of 4177bp and is most closely related to isolates SoMV-WA (GenBank accession no. HM163159.1) and ATCC PV-109 (GenBank accession no. GQ845002.2), with a nucleotide identity of 86.7%. The virus encodes four open reading frames (ORF) coding for four proteins, and phylogenetic analysis of capsid protein and RNA-dependent RNA polymerase (RdRp) showed that the strain was clustered into the species Sowbane Mosaic Virus (SoMV). The amino acid sequence identity of capsid protein was 89.6-90.9% to other isolates of SoMV, but 17.6-31.4% similar to other strains in the genus Sobemovirus, indicating a strain of Sowbane Mosaic Virus. This is the first report of SoMV in the feces of wild birds and in China, and it suggested that northern pintail likely plays an alternative role in the transmission of SoMV.

Ring-linear mixtures of semiflexible rubber bands

During the synthesis of ring polymers, it is quite common to obtain mixtures containing both ring and linear molecules. Recent studies, including experiments and simulations, have shown that even small quantities of linear molecules can significantly influence the shape of ring polymers, ultimately altering their rheological response. To further explore this phenomenon, we investigated blends of semiflexible linear and ring filaments by using disordered assemblies of open and closed rubber bands. We employed x-ray tomography to analyze the structure of these mixtures, focusing on how the length and composition of linear bands influenced the overall mixture. In contrast to the behavior observed in fully-flexible polymers, our findings revealed that increasing the concentration of linear bands could actually decrease the average size of rings within a semiflexible ring-linear mixture. This outcome is attributable to a reduction in inter-ring threading, which naturally occurs as the proportion of rings diminishes. To validate our findings, we conducted molecular dynamics simulations on semiflexible ring-linear polymer mixtures in bulk. These simulations confirmed that our results stem from the semiflexibility of the bands or chains rather than confinement or athermal conditions.

Macrocyclization of linear molecules by deep learning to facilitate macrocyclic drug candidates discovery

Interest in macrocycles as potential therapeutic agents has increased rapidly. Macrocyclization of bioactive acyclic molecules provides a potential avenue to yield novel chemical scaffolds, which can contribute to the improvement of the biological activity and physicochemical properties of these molecules. In this study, we propose a computational macrocyclization method based on Transformer architecture (which we name Macformer). Leveraging deep learning, Macformer explores the vast chemical space of macrocyclic analogues of a given acyclic molecule by adding diverse linkers compatible with the acyclic molecule. Macformer can efficiently learn the implicit relationships between acyclic and macrocyclic structures represented as SMILES strings and generate plenty of macrocycles with chemical diversity and structural novelty. In data augmentation scenarios using both internal ChEMBL and external ZINC test datasets, Macformer display excellent performance and generalisability. We showcase the utility of Macformer when combined with molecular docking simulations and wet lab based experimental validation, by applying it to the prospective design of macrocyclic JAK2 inhibitors.

Fast and Accurate Calculation of the UV-Vis Spectrum with the Modified Local Excitation Approximation.

The local excitation approximation (LEA), a method for the calculation of electronic excitations localized in a specific region of a molecule, has been modified with new approaches to enhance the accuracy of the original method. The primary concept behind LEA involves isolating the region of interest as a submolecule from the full molecule using a localization method, followed by calculating electronic excitations solely within this submolecule. In this study, we examined approaches that improve the accuracy in describing the region of interest, particularly its molecular orbital energies. Additionally, the localization method was extended with a new projection technique to accelerate calculations. These approaches were studied in time-dependent density functional theory (TDDFT) calculations applied to four testing systems with a chromophore as the region of interest: two basic linear molecules, acrolein surrounded by 24 water molecules, and a model of a green fluorescent protein. For all studied systems, the results of TDDFT calculations combined with LEA exhibited near-zero error when groups of atoms adjacent to the chromophore were explicitly included in the submolecule. This was achieved with at least a quadratic speedup of the calculation time as a function of the submolecule size.

Enhanced adsorption films of dendrimers on mild steel for super protection

ABSTRACT This study employed metronidazole skeletons based on the target branched molecules (TBMs) for achieving efficient anti-corrosion of mild steel in HCl solution. In contrast, the reference linear molecules (RLMs) carrying a single metronidazole framework were also made. The excellent corrosion resistance performance of the target dendrimers for mild steel electrodes in HCl solution was demonstrated. It is shown that the TBMs displayed a superior anti-corrosion effect for mild steel over RLMs in HCl medium at 298 K (at 0.15 mol/L, TBM1, 97.70% versus RLM1, 90.89%). It is shown that the standard Gibbs free energy changes of the adsorption of the TBMs on mild steel surface are below −33 kJ/mol (TBM1, −34.58 kJ/mol), thus an enhanced adsorption film was formed.

London Dispersion Interactions Imitate Pressure for Molecular Crystals.

The packing of molecular crystals, in which the constituent molecular units have no directional forces, is primarily controlled by weak London dispersion (LD) forces. These forces assist in stabilizing the system by bringing the molecular units into the proximity of each other. In this paper, the same effect is shown to be externally induced by pressure. The minimal pressure required to correctly describe the crystal structure without LD interactions (PLD) provides a quantifiable measure for the weak intermolecular interactions. LD forces are shown to be essential for an accurate description of the pressure-induced phase transitions across examples of linear, trigonal-planar, square-planar, tetrahedral, trigonal bipyramidal, and octahedral molecules.

Characterization of β-Glucans from Cereal and Microbial Sources and Their Roles in Feeds for Intestinal Health and Growth of Nursery Pigs.

The objectives of this review are to investigate the quantitative, compositional, and structural differences of β-glucans and the functional effects of β-glucans on the intestinal health and growth of nursery pigs. Banning antibiotic feed supplementation increased the research demand for antibiotic alternatives to maintain the intestinal health and growth of nursery pigs. It has been proposed that β-glucans improve the growth efficiency of nursery pigs through positive impacts on their intestinal health. However, based on their structure and source, their impacts can be extensively different. β-glucans are non-starch polysaccharides found in the cell walls of yeast (Saccharomyces cerevisiae), bacteria, fungi (Basidiomycota), and cereal grains (mainly barley and oats). The total β-glucan content from cereal grains is much greater than that of microbial β-glucans. Cereal β-glucans may interfere with the positive effects of microbial β-glucans on the intestinal health of nursery pigs. Due to their structural differences, cereal β-glucans also cause digesta viscosity, decreasing feed digestion, and decreasing nutrient absorption in the GIT of nursery pigs. Specifically, cereal β-glucans are based on linear glucose molecules linked by β-(1,3)- and β-(1,4)-glycosidic bonds with relatively high water-soluble properties, whereas microbial β-glucans are largely linked with β-(1,3)- and β-(1,6)-glycosidic bonds possessing insoluble properties. From the meta-analysis, the weight gain and feed intake of nursery pigs increased by 7.6% and 5.3%, respectively, through the use of yeast β-glucans (from Saccharomyces cerevisiae), and increased by 11.6% and 6.9%, respectively, through the use of bacterial β-glucans (from Agrobacterium sp.), whereas the use of cereal β-glucans did not show consistent responses. The optimal use of yeast β-glucans (Saccharomyces cerevisiae) was 50 mg/kg in nursery pig diets based on a meta-analysis. Collectively, use of microbial β-glucans can improve the intestinal health of nursery pigs, enhancing immune conditions, whereas the benefits of cereal β-glucans on intestinal health were not consistent.

Expression Profile and Regulatory Properties of m6A-Modified circRNAs in the Longissimus Dorsi of Queshan Black and Large White Pigs.

It is well known that N6-methyladenosine (m6A) is the most abundant modification in linear RNA molecules, but many circRNA molecules have now been found to have a wide range of m6A modification sites as well. However, there are few relevant studies and information on the expression profile and functional regulatory properties of m6A-modified circRNAs (m6A-circRNAs) in longissimus dorsi. In this study, a total of 12 putative m6A-circRNAs were identified and characterized in the longissimus dorsi of Queshan Black and Large White pigs-8 of them were significantly more expressed in the longissimus dorsi of Queshan Black than in Large White pigs, while the other 4 were the opposite. These 12 putative m6A-circRNAs were also found to act as miRNA sponge molecules to regulate fat deposition by constructing the ceRNA regulatory network. Enrichment analysis also revealed that the 12 m6A-circRNAs parent genes and their adsorbed miRNA target genes were widely involved in fat deposition and cell proliferation and differentiation-related pathways, such as the HIF-1 signaling pathway, the pentose phosphate pathway, the MAPK signaling pathway, the glycosphingolipid biosynthesis-lacto and neolacto series, and the TNF signaling pathway, suggesting that the analyzed m6A-circRNAs may be largely involved in the formation of pork quality. These results provide new information to study the regulatory properties of m6A-circRNAs in the formation of pork quality.

Characterizing the fundamental bending vibration of a linear polyatomic molecule for symmetry violation searches

Polyatomic molecules have been identified as sensitive probes of charge-parity violating and parity violating physics beyond the Standard Model (BSM). For example, many linear triatomic molecules are both laser-coolable and have parity doublets in the ground electronic state arising from the bending vibration, both features that can greatly aid BSM searches. Understanding the state is a crucial prerequisite to precision measurements with linear polyatomic molecules. Here, we characterize the fundamental bending vibration of YbOH using high-resolution optical spectroscopy on the nominally forbidden transition at 588 nm. We assign 39 transitions originating from the lowest rotational levels of the state, and accurately model the state’s structure with an effective Hamiltonian using best-fit parameters. Additionally, we perform Stark and Zeeman spectroscopy on the state and fit the molecule-frame dipole moment to D and the effective electron g-factor to . Further, we use an empirical model to explain observed anomalous line intensities in terms of interference from spin–orbit and vibronic perturbations in the excited state. Our work is an essential step toward searches for BSM physics in YbOH and other linear polyatomic molecules.

The Structure of Sulfated Polysaccharides from the Sea Cucumber <i>Holothuria</i> (<i>Stauropora</i>)<i> fuscocinerea</i>

Fucosylated chondroitin sulfate FCS-Hf and preparations of fucan sulfates Hf-Fuc1 and Hf-Fuc2 were isolated from the Vietnamese sea cucumber Holothuria (Stauropora) fuscocinerea. Separation of the polysaccharides was carried out using anion-exchange chromatography on DEAE-Sephacel. The structure of polysaccharides was established by determinations of the content of monosaccharides and sulfate, as well as by NMR spectra. It was shown that FCS-Hf was built of the repeating trisaccharide fragments, with alternating 3‑linked N-acetyl-β-D-galactosamine and 4-linked β-D-glucuronic acid residues forming the main polymer chain, which carries α-L-fucose residues as side branches attached to O3 of glucuronic acid. The regular structure of polymer is masked by an uneven distribution of sulfate groups attached to fucose residues (2,4-disulfate, 3,4-disulfate and 4-monosulfate in a ratio of 2 : 2 : 1) and galactosamine residues (4,6-disulfate and 4-monosulfate in a ratio of 3 : 1). It was also shown that fucan sulfate Hf-Fuc1 contained predominantly linear molecules built of 4-linked α-L-fucose 3-sulfate residues, while Hf-Fuc2 appeared to be a mixture of several related linear and branched fucan sulfates containing 3-linked and 4-linked α-L-Fuc residues sulfated at different positions.

Study of isobaric vapor–liquid equilibria of diethyl carbonate + ethylene carbonate for lithium-ion battery electrolyte solvent recycling

The limited life-cycle of lithium-ion batteries (LIBs) remains a significant issue for the industry. Recycling electrolytes from the batteries is one crucial aspect of LIBs recycling, which can conserve resources and reduce environmental pollution. The vapor–liquid equilibrium (VLE) data and models for the currently widely used carbonates, such as ethylene carbonate (EC), dimethyl carbonate (DMC), propylene carbonate (PC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC), can play an important role in designing the recycling process. In this work, the VLE data of DEC and EC is measured for the first time. A sophisticated equation of state, the Perturbed-Chain Polar Statistical Associating Fluid Theory, is used to establish the VLE model, not only for the newly measured DEC and EC system but also for other carbonates and their mixtures. Through the discussion of how the molecular characteristics of carbonates influence the VLE behavior, the dipolar character of linear carbonate molecules has been revealed. This demonstrates the power and importance of sophisticated modelling approaches in investigating molecular behavior of electrolyte solvents in the context of LIB recycling. Hence, this work provides valuable experimental and model data for designing recycling processes of electrolyte solvents and offers molecular insight into carbonates.

Cohesin‐mediated DNA loop extrusion resolves sister chromatids in G2 phase

Genetic information is stored in linear DNA molecules, which are highly folded inside cells. DNA replication along the folded template path yields two sister chromatids that initially occupy the same nuclear region in an intertwined arrangement. Dividing cells must disentangle and condense the sister chromatids into separate bodies such that a microtubule‐based spindle can move them to opposite poles. While the spindle‐mediated transport of sister chromatids has been studied in detail, the chromosome‐intrinsic mechanics presegregating sister chromatids have remained elusive. Here, we show that human sister chromatids resolve extensively already during interphase, in a process dependent on the loop‐extruding activity of cohesin, but not that of condensins. Increasing cohesin's looping capability increases sister DNA resolution in interphase nuclei to an extent normally seen only during mitosis, despite the presence of abundant arm cohesion. That cohesin can resolve sister chromatids so extensively in the absence of mitosis‐specific activities indicates that DNA loop extrusion is a generic mechanism for segregating replicated genomes, shared across different Structural Maintenance of Chromosomes (SMC) protein complexes in all kingdoms of life.

State of water in various environments: Aliphatic ketones. MIR/NIR spectroscopic, dielectric and theoretical studies

This work provides new insight into the state of water in a series of aliphatic ketones. For our studies, we selected nine aliphatic ketones of different size and structure to examine the effect of various structural motifs on behavior of water in the mixtures. Our results reveal that conformational flexibility of aliphatic chains in the linear ketones allows for effective shielding of the carbonyl group, and this flexibility is the main reason for poor solubility of water. Hence, in the linear ketones molecules of water are involved mostly in ketone-water interactions, while the water-water interactions are rare. Higher solubility of water in the cyclic ketones allows for creation of clusters of water, where the molecules are in water-like environment. The temperature rise in wet cyclic ketones increases population of ketone-water interactions at the expense of the water-water ones, while in the linear ketones and 2,6-dimethylcyclohexanone at an elevated temperature there is an increase in the population of singly bonded water at the expense of the doubly bonded one. DFT calculations reveal that the substitution of cyclohexanone by a single methyl group does not affect the strength of the ketone-water interactions, while it has a significant impact on the solubility of water in the ketone. The most important conclusion from this study is that the accessibility of the carbonyl group is the most important factor determining the intermolecular interactions and solubility of water in aliphatic ketones.

Impact of the inner solute structure on the electrostatic mean-field and strong-coupling regimes of macromolecular interactions.

The structural diversity of the solute molecules involved in biomolecular processes necessitates the characterization of the forces between charged macromolecules beyond the point-ion description. From the field-theoretic partition function of an electrolyte confined between two anionic membranes, we derive a contact-value identity valid for general intramolecular solute structure and electrostatic coupling strength. In the electrostatic mean-field regime, the inner charge spread of the solute particles is shown to induce the twofold enhancement of the short-range Poisson-Boltzmann level membrane repulsion and a longer-range depletion attraction. Our contact theorem indicates that the twofold repulsion enhancement by solute size is equally present in the opposite strong-coupling regime of linear and spherical solute molecules. Upon the inclusion of the dielectric contrast between the electrolyte and the interacting membranes, the emerging polarization forces substantially amplify the solute specificity of the macromolecular interactions. Namely, the finite size of the dumbbell-like solute particles composed of similar terminal charges weakens the intermembrane repulsion. However, the extended structure of the solute molecules carrying opposite elementary charges such as ionized atoms and zwitterionic molecules enhances the membrane repulsion by several factors. We also show that these polarization forces can extend the range of the solute structure effects up to intermembrane distances exceeding the solute size by an order of magnitude. This radical alteration of the intermembrane interactions by the salt structure identifies the solute specificity as a key ingredient of the thermodynamic stability in colloidal systems.