Effects of MEL-A on apoptosis of B16 cells.

<p>Cells were treated with different concentrations of MEL-A for 24 h. (a) ~ (f) refer to the cell population changes of B16 treated by 0, 6.0, 9.0, 12.0, 15.0, 25.0 μg/mL MEL-A, respectively. Most MEL-A-induced cells were evident in B2 fraction, and the tendency of the induced cells apoptosis was in a dose-dependent manner. Mean ± SD, n = 3.</p

The viabilities of B16 cells and NIH3T3 cells in response to MEL-A treatments.

<p>(a), B16 cells treated with increasing doses of MEL-A had obvious changes. (b), the viability of the normal NIH3T3 cells treated by 15.0 μg/mL MEL-A for 72 h. (c, d, e, f) refers to the photographs of untreated B16 cells, and cells treated with MEL-A for 24 h, 48 h and 72 h. (g, h, m, n) refers to the photographs of untreated NIH3T3 cells and cells treated with MEL-A for 24 h, 48 h, and 72 h, respectively.</p

¹H NMR spectrum and ¹³C NMR spectrum of MEL-A.

<p>(a), ¹H signals at 0~7.0 ppm and (b), ¹³C signals at 0~180.0 ppm. (c), Structure of MELs, MEL-A: R₁ = R₂ = Ac; MEL-B: R₁ = Ac, R₂ = H; MEL-C: R₁ = H, R₂ = Ac; MEL-D: R₁ = R₂ = H, n = 6–16.</p

Effects of MEL-A on cell cycle distributions of B16 cells.

<p>Cells were treated with different concentrations of MEL-A for 24 h. (a) ~ (e) refer to the cell cycle distributions of B16 cells treated by 0, 9.0, 15.0, 20.0, 25.0 μg/mL MEL-A, respectively. G1/G0, S, G2/M and Sub-G1 indicate the different cell phases. Mean ± SD, n = 3. The results in (f) summarized the relative ratios of each cell cycle, indicating that MEL-A caused cell cycle arrest at the S phase. The cell population of Sub-G1 phase was slightly increased with exposure to above 15.0 μg/mL of MEL-A.</p

Detected MEL-A homologs with various masses and fatty acids chain combinations.

<p>Detected MEL-A homologs with various masses and fatty acids chain combinations.</p

The solution state of MEL-A in water.

<p>(a), mean particle sizes of MEL-A solution at the concentrations of 12.0 mg/L. (b), mean particle sizes of MEL-A solution at the concentrations of 12.0 μg/L. (c), the surface tension of MEL-A changed with various concentrations. The concentration at the curve break records the critical micelle concentration (CMC).</p

Biosurfactant–Protein Interaction: Influences of Mannosylerythritol Lipids‑A on β‑Glucosidase

In this work, the influences of a biosurfactant, mannosylerythritol lipids-A (MEL-A) toward β-glucosidase activity and their molecular interactions were studied by using differential scanning calorimetry (DSC), circular dichroism spectroscopy (CD), isothermal titration calorimetry (ITC), and docking simulation. The enzyme inhibition kinetics data showed that MEL-A at a low concentration (< critical micelle concentration (CMC), 20.0 ± 5.0 μM) enhanced β-glucosidase activity, whereas it inhibited the enzyme activity at higher concentrations more than 20.0 μM, followed by a decreased <i>V</i>_max and <i>K</i>_m of β-glucosidase. The thermodynamics and structural data demonstrated that the midpoint temperature (<i>T</i>_m) and unfolding enthalpy (Δ<i><i>H</i></i>) of β-glucosidase was shifted to high values (76.6 °C, 126.3 J/g) in the presence of MEL-A, and the secondary structure changes of β-glucosidase, including the increased α-helix, β-turn, or random coil contents, and a decreased β-sheet content were caused by MEL-A at a CMC concentration. The further ITC and docking simulations suggested the bindings of MEL-A toward β-glucosidase were driven by weak hydrophobic interactions happened between the amino acid residues of β-glucosidase and the fatty acid residues of MEL-A, in addition to hydrogen bonds between amino acids and hydroxyl in glycosyl residues of this biosurfactant

SnO₂/Reduced Graphene Oxide Interlayer Mitigating the Shuttle Effect of Li–S Batteries

The short cycle life of lithium–sulfur batteries (LSBs) plagues its practical application. In this study, a uniform SnO₂/reduced graphene oxide (denoted as SnO₂/rGO) composite is successfully designed onto the commercial polypropylene separator for use of interlayer of LSBs to decrease the charge-transfer resistance and trap the soluble lithium polysulfides (LPSs). As a result, the assembled devices using the separator modified with the functional interlayer (SnO₂/rGO) exhibit improved cycle performance; for instance, over 200 cycles at 1C, the discharge capacity of the cells reaches 734 mAh g^–1. The cells also display high rate capability, with the average discharge capacity of 541.9 mAh g^–1 at 5C. Additionally, the mechanism of anchoring behavior of the SnO₂/rGO interlayer was systematically investigated using density functional theory calculations. The results demonstrate that the improved performance is related to the ability of SnO₂/rGO to effectively absorb S₈ cluster and LPS. The strong Li–O/Sn–S/O–S bonds and tight chemical adsorption between LPS and SnO₂ mitigate the shuttle effect of LSBs. This study demonstrates that engineering the functional interlayer of metal oxide and carbon materials in LSBs may be an easy way to improve their rate capacity and cycling life

Controllably Designed “Vice-Electrode” Interlayers Harvesting High Performance Lithium Sulfur Batteries

An interlayer has been regarded as a promising mediator to prolong the life span of lithium sulfur batteries because its excellent absorbability to soluble polysulfide efficiently hinders the shuttle effect. Herein, we designed various interlayers and understand the working mechanism of an interlayer for lithium sulfur batteries in detail. It was found that the electrochemical performance of a S electrode for an interlayer located in cathode side is superior to the pristine one without interlayers. Surprisingly, the performance of the S electrode for an interlayer located in anode side is poorer than that of pristine one. For comparison, glass fibers were also studied as a nonconductive interlayer for lithium sulfur batteries. Unlike the two interlayers above, these nonconductive interlayer did displays significant capacity fading because polysulfides were adsorbed onto insulated interlayer. Thus, the nonconductive interlayer function as a “dead zone” upon cycling. Based on our findings, it was for the first time proposed that a controllably optimized interlayer, with electrical conductivity as well as the absorbability of polysulfides, may function as a “vice-electrode” of the anode or cathode upon cycling. Therefore, the cathodic conductive interlayer can enhance lithium sulfur battery performance, and the anodic conductive interlayer may be helpful for the rational design of 3D networks for the protection of lithium metal

Metal–Organic Frameworks-Derived Co₂P@N-C@rGO with Dual Protection Layers for Improved Sodium Storage

The Co₂P nanoparticles hybridized with unique N-doping carbon matrices have been successfully designed employing ZIF-67 as the precursor via a facile two-step procedure. The Co₂P nanostructures are shielded with reduced graphene oxide (rGO) to enhance electrical conductivity and mitigate volume expansion/shrinkage during sodium storage. As anode materials for sodium-ion batteries (SIBs), the novel architectures of Co₂P@N-C@rGO exhibited excellent sodium storage performance with a high reversible capacity of 225 mA h g^–1 at 50 mA g^–1 after 100 cycles. Our study demonstrates the significant potential of Co₂P@N-C@rGO as anode materials for SIBs