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The importance of individual nutrients for microbial strain robustness and coexistence in habitats containing different members of the same species is not well understood. To address this for Lactiplantibacillus plantarum in food fermentations, we performed comparative genomics and examined the nutritive requirements and competitive fitness for L. plantarum strains B1.1 and B1.3 isolated from a single sample of teff injera fermentation batter. Compared to B1.1 and other L. plantarum strains, B1.3 has a smaller genome, limited biosynthetic capacities, and large mobilome. Despite these differences, B1.3 was equally competitive with B1.1 in a suspension of teff flour. In commercially sourced, nutrient-replete MRS (cMRS) medium, strain B1.3 reached 3-fold-higher numbers than B1.1 within 2 days of passage. Because B1.3 growth and competitive fitness were poor in mMRS medium (here called mMRS), a modified MRS medium lacking beef extract, we used mMRS to identify nutrients needed for robust B1.3 growth. No improvement was observed when mMRS was supplemented with nucleotides, amino acids, vitamins, or monovalent metals. Remarkably, the addition of divalent metal salts increased the growth rate and cell yields of B1.3 in mMRS. Metal requirements were confirmed by inductively coupled plasma mass spectrometry, showing that total B1.3 intracellular metal concentrations were significantly (up to 2.7-fold) reduced compared to B1.1. Supplemental CaCl2 conferred the greatest effect, resulting in equal growth between B1.1 and B1.3 over five successive passages in mMRS. Moreover, calcium supplementation reversed a B1.3 strain-specific, stationary-phase, flocculation phenotype. These findings show how L. plantarum calcium requirements affect competitive fitness at the strain level. IMPORTANCE Ecological theory states that the struggle for existence is stronger between closely related species. Contrary to this assertion, fermented foods frequently sustain conspecific individuals, in spite of their high levels of phylogenetic relatedness. Therefore, we investigated two isolates of Lactiplantibacillus plantarum, B1.1 and B1.3, randomly selected from a single batch of teff injera batter. These strains spanned the known genomic and phenotypic range of the L. plantarum species, and in laboratory culture medium used for strain screening, B1.3 exhibited poor growth and was outcompeted by the more robust strain B1.1. Nonetheless, B1.1 and B1.3 were equally competitive in teff flour. This result shows how L. plantarum has adapted for coexistence in that environment. The capacity for the single macronutrient calcium to restore B1.3 competitive fitness in laboratory culture medium suggests that L. plantarum intraspecies diversity found in food systems is fine-tuned to nutrient requirements at the strain level.

Recently, lipid nanoparticles (LNPs) have been extensively investigated as non-viral carriers of nucleic acid vaccines due to their high transport efficiency, safety, and straightforward production and scalability. However, the molecular mechanism underlying the interactions between nucleic acids and phospholipid bilayers within LNPs remains elusive. In this study, we employed the all-atom molecular dynamics simulation to investigate the interactions between single-stranded nucleic acids and a phospholipid bilayer. Our findings revealed that hydrophilic bases, specifically G in single-stranded RNA (ssRNA) and single-stranded DNA (ssDNA), displayed a higher propensity to form hydrogen bonds with phospholipid head groups. Notably, ssRNA exhibited stronger binding energy than ssDNA. Furthermore, divalent ions, particularly Ca2+, facilitated the binding of ssRNA to phospholipids due to their higher binding energy and lower dissociation rate from phospholipids. Overall, our study provides valuable insights into the molecular mechanisms underlying nucleic acid-phospholipid interactions, with potential implications for the nucleic acids in biotherapies, particularly in the context of lipid carriers. [ABSTRACT FROM AUTHOR]

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Monocyclic nitrogen-rich 3-(aminomethyl)-4,5-diamine-1,2,4-triazole (1) and fused cyclic 3,7-diamine-6-(aminomethyl)-[1,2,4] triazolo [4,3-b] [1,2,4] triazole (9) were synthesized through the convenient cyclization reaction from the readily available reactant. Their energetic salts with high nitrogen content were proved to be rare examples of divalent monocyclic/fused cyclic cationic salts according to the single crystal analyses. The structure of intermediate B was also identified and verified by its trivalent cation crystal 17.5H2O indirectly. Energetic compounds 2e8 and 10e17 were fully characterized by NMR spectroscopy, infrared spectroscopy, differential scanning calorimetry, elemental analysis. These energetic salts exhibit good thermal stability with decomposition temperatures ranged from 182 °C to 245 °C. The sensitivity of compounds 2, 6, 10 and 14 is similar or superior to that of RDX while the others were much more insensitive to mechanical stimulate. Furthermore, detonation velocity of 10 (8843 m/s) surpass that of RDX (D = 8795 m/s). Considering the high gas production volume (-808 L/kg) of 2, 4, 10 and 12, constant-volume combustion experiments were conduct to evaluate their gas production capacities specifically. These compounds possess much higher maximum gas-production pressures (Pmax: 7.88e10.08 MPa) than the commonly used reagent guanidine nitrate (GN: Pmax = 4.20 MPa), which indicate their strong gas production capacity. [ABSTRACT FROM AUTHOR]

Developing environmental purification techniques for water resources is important for realising a sustainable society. Inorganic ion-exchanger is one of the research themes in technological development, particularly titania nanotubes (TNTs), which have been studied for the removal of cationic heavy metals and radionuclides. Although many studies have reported the adsorption properties of TNTs, the sorption behaviour and state of intercalated cations in the structure are still unclear. In this study, the sorption properties of Co2+, Ni2+, Zn2+, and Sr2+ on TNTs were investigated using the equilibrium isotherms, kinetics and detailed analysis of residues under simple batch conditions. The sorption isotherms of cations on TNTs were fitted with the Langmuir model, and the maximum sorption amount (Qmax) was in the order of Sr2+ (1.13 mmol/g) > Zn2+ (0.99 mmol/g) > Co2+ (0.85 mmol/g) > Ni2+ (0.78 mmol/g). The sorption kinetics data fitted well with pseudo second-order model. The X-ray analysis indicated that the Sr2+ sorption on TNTs resulted from the ion-exchange and formation of carbonate compounds. In contrast, the Co2+, Ni2+, and Zn2+ ions were estimated to be incorporated in an ionic state in the TNT interlayer by ion-exchange with Na+ and H+ via chelation with surface hydroxyl groups on TNTs. These results indicate that the crystallographic properties of TNTs, ionic size, and chemical property of the target cation, and reactivity with carbonic acid are important factors to consider in the design of water purification systems using TNTs.

[Display omitted] • Dually charged membranes were prepared by loading UiO-66-(NH 2) 2 into polyamide layer. • The amino-rich nanochannels could be regulated by ligand replacement strategy. • Satisfactory rejection for both CaCl 2 and Na 2 SO 4 could achieved with high permeance. • UiO-66-(NH 2) 2 played a crucial role in the enhanced rejection of divalent cations. • Migration energy barrier across UiO-66-(NH 2) 2 was an order of magnitude higher. Traditional polyamide nanofiltration membranes suffer from permeability-selectivity trade-off limitation and unsatisfactory rejection for divalent cations. Herein, a novel dually charged membrane was constructed by incorporating positively charged UiO-66-(NH 2) 2 into the negatively charged polyamide layer. Thanks to the customizable nanochannels of metal-organic frameworks, the amino-rich nanochannels of UiO-66-(NH 2) 2 could be fabricated through a ligand replacement strategy. UiO-66-(NH 2) 2 played a crucial role in the enhanced rejection of divalent cations, meanwhile negatively charged polyamide surface guaranteed the efficient Na 2 SO 4 rejection. Satisfactory rejections of CaCl 2 (96.07 %) and Na 2 SO 4 (90.62 %) were achieved simultaneously by optimal TFN-D5. Meanwhile, TFN-D5 owned the greatly-improved water permeance of 19.44 LMH/bar, which was about 1.5 times better than that of the TFC-control. Calculations based on density functional theory further confirmed UiO-66-(NH 2) 2 rejected Ca2+ efficiently since the migration energy barrier across UiO-66-(NH 2) 2 was an order of magnitude higher than that of UiO-66-NH 2 and UiO-66. Moreover, the desirable rejections were beyond 94 % towards many divalent cation salts including MgCl 2 , NiCl 2 , PbCl 2 , MnCl 2 , CdCl 2 and ZnCl 2. Thus, this work provided an efficient way to realize the synergistic removal of both divalent cations and anions. [ABSTRACT FROM AUTHOR]

[Display omitted] • EDTA functionalized graphene oxide (EDTA-GO) showed a high aqueous dispersiblity. • Liquid crystalline phase was observed from the suspension of EDTA-GO. • EDTA-GO was strongly cross-linked with divalent cations. • The mechanical properties of EDTA-GO films were enhanced with ionic cross-linking. Graphene oxide is functionalized with ethylenediaminetetraacetic acid groups to investigate the effect of ethylenediaminetetraacetic acid groups on its colloidal, assembly, and ionic cross-linking behaviors. Ethylenediaminetetraacetic acid-functionalized graphene oxide exhibits a high aqueous dispersibility for presenting a nematic liquid-crystalline phase which is an important factor for fabrication of the well-ordered laminated films. Ethylenediaminetetraacetic acid-graphene oxide films show a distinct internal structure from graphene oxide films owing to the heterogeneous surface of ethylenediaminetetraacetic acid-graphene oxide sheets composed of partially reduced and ethylenediaminetetraacetic acid decorated regions. In addition, the mechanical properties of ethylenediaminetetraacetic acid-graphene oxide films are more enhanced by ionic cross-linking with divalent cations, and their degree of mechanical enhancement is also more dependent on the type of cations than graphene oxide films. The interesting behaviors of ethylenediaminetetraacetic acid-graphene oxide suggest the ethylenediaminetetraacetic acid functionalization can greatly improve the potential of graphene oxide derivatives to develop a high-performance structural material. [ABSTRACT FROM AUTHOR]

Ductins are a family of homologous and structurally similar membrane proteins with 2 or 4 trans-membrane alpha-helices. The active forms of the Ductins are membranous ring- or star-shaped oligomeric assemblies and they provide various pore, channel, gap-junction functions, assist in membrane fusion processes and also serve as the rotor c-ring domain of V-and F-ATPases. All functions of the Ductins have been reported to be sensitive to the presence of certain divalent metal cations (Me 2+ ), most frequently Cu 2+ or Ca 2+ ions, for most of the better known members of the family, and the mechanism of this effect is not yet known. Given that we have earlier found a prominent Me 2+ binding site in a well-characterised Ductin protein, we hypothesise that certain divalent cations can structurally modulate the various functions of Ductin assemblies via affecting their stability by reversible non-covalent binding to them. A fine control of the stability of the assembly ranging from separated monomers through a loosely/weakly to tightly/strongly assembled ring might render precise regulation of Ductin functions possible. The putative role of direct binding of Me 2+ to the c-ring subunit of active ATP hydrolase in autophagy and the mechanism of Ca 2+ -dependent formation of the mitochondrial permeability transition pore are also discussed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Sebők-Nagy, Blastyák, Juhász and Páli.)

• An increase of PO number will reduce the interfacial tension. • Adding Ca2+ can achieve ultralow value at lower PO number and wider ACN range. • The ability to reduce the IFT of adding Mg2+ is weaker than that of Ca2+. • Surface active substances in the crude oil will adsorb competitively on the interface. Extended surfactants have shown great potential in enhanced oil recovery (EOR). In this paper, the effects of extended surfactant concentration, polypropylene oxide (PO) number, and various counter ions (Na+, Ca2+, and Mg2+) on the oil–water interfacial tension (IFT) of extended surfactant solutions were investigated in detail. The selected extended surfactants were sodium dodecyl polyoxypropylene sulfate (L-C 12 PO m S, m = 5, 10, 15). Based on our experimental results, under NaCl conditions, with an increase in the PO number, the space occupied by the surfactant molecules on the side of the oil phase increases, which matches the size of the anionic head, and the surfactant film becomes tight. An ultralow IFT value appears for L-C 12 PO 15 S at 0.5% NaCl against decane. The addition of bivalent cations can significantly reduce the IFT. As the Ca2+ concentration increases, IFTs of APS solutions against alkanes can achieve ultralow values at lower PO numbers and against alkanes with a wide ACN range. For the MgCl 2 system, the smaller hydration radius of Mg2+ improves the tightness of the anionic head, resulting in a crowded arrangement of the PO chains on the oil phase side. Therefore, the ability of Mg2+ to reduce the IFT against alkanes is weaker than that of Ca2+. Moreover, the surface-active substances in the crude oil adsorb competitively on the interface, resulting in an increase in IFT. By adding Ca2+or Mg2+, a tight adsorption film of surfactant molecules will be formed, and the IFT value reaches ultralow against crude oil. The studies in this paper have important implications for the application of extended surfactant solutions to enhance oil recovery under high salt reservoir conditions. [ABSTRACT FROM AUTHOR]