Effect of Co-Existing Cations and Anions on the Adsorption of Antibiotics on Iron-Containing Minerals

The adsorption of antibiotics on minerals is an important process in their environment behavior. The adsorption behavior of antibiotics on iron-containing minerals and the effect of co-existing cations and anions were studied in this work. Magnetite, hematite, goethite and kaolin were selected as the representative minerals and characterized by SEM, XRD and BET. A total of eight antibiotics, including three quinolones, three sulfonamides and two mycins were chosen as the research targets. Results showed a higher adsorption amount of quinolones than that of sulfonamides and mycins on the surface of iron-containing minerals in most mineral systems. The adsorption isotherms of quinolones can be well fitted using the Freundlich models. The effects of five cations and five anions on the adsorption of quinolones were investigated, among which Mg²⁺, Ca²⁺, HCO₃⁻ and H₂PO₄⁻ mainly showed significant inhibition on the adsorption, while the effects of K⁺, Na⁺, NH₄⁺, Cl⁻, NO₃⁻ and SO₄²⁻ showed less. Natural surface water samples were also collected and used as media to investigate the adsorption behavior of quinolones on iron-containing minerals. The buffering capacity of the natural water kept the reaction solution at circumneutral conditions, and the adsorption amount was mostly promoted in the goethite system (from 0.56~0.78 μmol/g to 0.52~1.43 μmol/g), but was inhibited in the other systems (magnetite: from 1.13~1.33 μmol/g to 0.45~0.76 μmol/g; hematite: from 0.52~0.65 μmol/g to 0.02~0.18 μmol/g; kaolin: from 1.98~1.99 μmol/g to 0.90~1.40 μmol/g). The results in this work help to further understand the transportation and fate of antibiotics in an aqueous environment.     

Efficient Preparation of Small-Sized Transition Metal Dichalcogenide Nanosheets by Polymer-Assisted Ball Milling

Two-dimensional (2D) transition metal dichalcogenide nanosheets (TMDC NSs) have attracted growing interest due to their unique structure and properties. Although various methods have been developed to prepare TMDC NSs, there is still a great need for a novel strategy combining simplicity, generality, and high efficiency. In this study, we developed a novel polymer-assisted ball milling method for the efficient preparation of TMDC NSs with small sizes. The use of polymers can enhance the interaction of milling balls and TMDC materials, facilitate the exfoliation process, and prevent the exfoliated nanosheets from aggregating. The WSe₂ NSs prepared by carboxymethyl cellulose sodium (CMC)-assisted ball milling have small lateral sizes (8~40 nm) with a high yield (~60%). The influence of the experimental conditions (polymer, milling time, and rotation speed) on the size and yield of the nanosheets was studied. Moreover, the present approach is also effective in producing other TMDC NSs, such as MoS₂, WS₂, and MoSe₂. This study demonstrates that polymer-assisted ball milling is a simple, general, and effective method for the preparation of small-sized TMDC NSs.     

Establishment and Application of a Predictive Growth Kinetic Model of Salmonella with the Appearance of Two Other Dominant Background Bacteria in Fresh Pork

To better guide microbial risk management and control, growth kinetic models of Salmonella with the coexistence of two other dominant background bacteria in pork were constructed. Sterilized pork cutlets were inoculated with a cocktail of Salmonella Derby (S. Derby), Pseudomonas aeruginosa (P. aeruginosa), and Escherichia coli (E. coli), and incubated at various temperatures (4–37 °C). The predictive growth models were developed based on the observed growth data. By comparing R² of primary models, Baranyi models were preferred to fit the growth curves of S. Derby and P. aeruginosa, while the Huang model was preferred for E. coli (all R² ≥ 0.997). The secondary Ratkowsky square root model can well describe the relationship between temperature and μ_max (all R² ≥ 0.97) or Lag (all R² ≥ 0.98). Growth models were validated by the actual test values, with B_f and A_f close to 1, and MSE around 0.001. The time for S. Derby to reach a pathogenic dose (10⁵ CFU/g) at each temperature in pork was predicted accordingly and found to be earlier than the time when the pork began to be judged nearly fresh according to the sensory indicators. Therefore, the predictive microbiology model can be applied to more accurately predict the shelf life of pork to secure its quality and safety.     

Iridium-Catalyzed and pH-Dependent Reductions of Nitroalkenes to Ketones

A highly chemoselective conversion of α,β-disubstituted nitroalkenes to ketones is developed. An acid-compatible iridium catalyst serves as the key to the conversion. At a 2500 S/C ratio, nitroalkenes were readily converted to ketones in up to 72% isolated yields. A new mechanistic mode involving the reduction of nitroalkene to nitrosoalkene and N-alkenyl hydroxylamine is proposed. This conversion is ready to amplify to a gram-scale synthesis. The pH value plays an indispensable role in controlling the chemoselectivity.     

Natural Deep Eutectic Solvent-Assisted Extraction,Structural Characterization,and Immunomodulatory Activity of Polysaccharides from Paecilomyces hepiali

Polysaccharides, which can be affected by different preparations, play a crucial role in the biological function of Paecilomyces hepiali (PHPS) as a health food. To explore high-valued polysaccharides and reduce the negative influence of human involvement, a green tailorable deep eutectic solvent (DES) was applied to optimize the extraction of polysaccharides (PHPS-D), followed by the evaluation of the structural properties and immunomodulation by comparison with the hot-water method (PHPS-W). The results indicated that the best system for PHPS-D was a type of carboxylic acid-based DES consisting of choline chloride and succinic acid in the molar ratio of 1:3, with a 30% water content. The optimal condition was as follows: liquid–solid ratio of 50 mL/g, extraction temperature of 85 °C, and extraction time of 1.7 h. The actual PHPS-D yield was 12.78 ± 0.17%, which was obviously higher than that of PHPS-W. The structural characteristics suggested that PHPS-D contained more uronic acid (22.34 ± 1.38%) and glucose (40.3 ± 0.5%), with a higher molecular weight (3.26 × 10⁵ g/mol) and longer radius of gyration (78.2 ± 3.6 nm), as well as extended chain conformation, compared with PHPS-W, and these results were confirmed by AFM and SEM. Immunomodulatory assays suggested that PHPS-D showed better performance than PHPS-W regarding pinocytic activity and the secretion of NO and pro-inflammatory cytokines (IL-6, TNF-α and IL-1β) by activating the corresponding mRNA expression in RAW264.7 cells. This study showed that carboxylic acid-based DES could be a promising tailorable green system for acidic polysaccharide preparation and the valorization of P. hepiali in functional foods.     

Phenylpropanoid Derivatives from the Tuber of Asparagus cochinchinensis with Anti-Inflammatory Activities

Three undescribed phenylpropanoid derivatives, including two new bibenzyl constituents (1–2), one new stilbene constituent (3), together with five known compounds stilbostemin F (4), dihydropinosylvin (5), 2-(4-hydroxyphenyl)ethyl benzoate (6), 1-(4-hydroxybenzoyl)ethanone (7), and 4-hydroxy-3-prenylbenzoic acid (8), were isolated from the tuber of Asparagus cochinchinensis. The structures of 1–8 were elucidated according to UV, IR, HRMS, 1D and 2D-NMR methods together with the published literature. All of the isolated compounds were assessed for anti-inflammatory activity by acting on lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells in vitro. The results showed that compounds 2 and 5 were found to inhibit the production of nitric oxide (NO) with the IC₅₀ value of 21.7 and 35.8 µM, respectively. In addition, further studies found that compound 2 demonstrated concentration-dependent suppression of the protein expression of iNOS and exerted anti-inflammatory activity via the NF-κB signalling pathway. The present data suggest that phenylpropanoid derivatives from the tuber of A. cochinchinensis might be used as a potential source of natural anti-inflammatory agents.     

Semisynthesis and Pesticidal Activities of Novel Cholesterol Ester Derivatives Containing Cinnamic Acid-like Fragments

Due to the extensive use of agrochemicals resulting in the emergence of pesticide resistance and ecological environment problems, the research and development of new alternatives for crop protection is highly desirable. In order to discover potent natural product-based insecticide candidates, a series of new cholesterol ester derivatives containing cinnamic acid-like fragments at the C-7 position were synthesized. Some derivatives showed potent pesticidal activities. Against Mythimna separata Walker, compounds 2a, Id, Ig, and IIg showed 2.1–2.4-fold growth-inhibitory activity of the precursor cholesterol. Against Plutella xylostella Linnaeus, compounds Ig, IIf, and IIi exhibited 1.9–2.1-fold insecticidal activity of cholesterol. These results will pave the way for the future synthesis of cholesterol-based derivatives as agrochemicals.     

Self-Assembled CuCo2S4 Nanoparticles for Efficient Chemo-Photothermal Therapy of Arterial Inflammation

Cardiovascular disease caused by atherosclerosis (AS) seriously affects human health. Photothermal therapy (PTT) brings hope to the diagnosis and treatment of AS, with the development of nanotechnology. To improve treatment efficiency, self-assembled CuCo₂S₄ nanocrystals (NCs) were developed as a drug-delivery nanocarrier, triggered by near-infrared (NIR) light for efficient chemophotothermal therapy of arterial inflammation. The as-prepared self-assembled CuCo₂S₄ NCs exhibited excellent biocompatibility and a very high chloroquine (CL)-loading content. In addition, the self-assembled CuCo₂S₄ NCs/CL nanocomposites showed good photothermal performance, due to strong absorption in the NIR region, and the release of CL from the NCs/CL nanocomposites was driven by NIR light. When illuminated by NIR light, both PTT from the NCs and chemotherapy from the CL were simultaneously triggered, resulting in killing macrophages with a synergistic effect. Moreover, chemo-photothermal therapy with CuCo₂S₄ NCs/CL nanocomposites showed an effective therapeutic effect for arterial inflammation, in vivo. Our work demonstrated that chemo-photothermal therapy could be a promising strategy for the treatment of arterial inflammation against atherosclerosis.     

Design Two Novel Tetrahydroquinoline Derivatives against Anticancer Target LSD1 with 3D-QSAR Model and Molecular Simulation

Lysine-specific demethylase 1 (LSD1) is a histone-modifying enzyme, which is a significant target for anticancer drug research. In this work, 40 reported tetrahydroquinoline-derivative inhibitors targeting LSD1 were studied to establish the three-dimensional quantitative structure–activity relationship (3D-QSAR). The established models CoMFA (Comparative Molecular Field Analysis (q² = 0.778, Rpred2 = 0.709)) and CoMSIA (Comparative Molecular Similarity Index Analysis (q² = 0.764, Rpred2 = 0.713)) yielded good statistical and predictive properties. Based on the corresponding contour maps, seven novel tetrahydroquinoline derivatives were designed. For more information, three of the compounds (D1, D4, and Z17) and the template molecule 18x were explored with molecular dynamics simulations, binding free energy calculations by MM/PBSA method as well as the ADME (absorption, distribution, metabolism, and excretion) prediction. The results suggested that D1, D4, and Z17 performed better than template molecule 18x due to the introduction of the amino and hydrophobic groups, especially for the D1 and D4, which will provide guidance for the design of LSD1 inhibitors.     

In situ monitoring of functional activity of extracellular matrix stiffness-dependent multidrug resistance protein 1 using scanning electrochemical microscopy

Extracellular matrix (ECM) stiffness affects the drug resistance behavior of cancer cells, while multidrug resistance protein 1 (MRP1) on the cell membrane confers treatment resistance via actively transporting drugs out of cancer cells. However, the relationship between ECM stiffness and MRP1 functional activity in cancer cells remains elusive, mainly due to the technical challenge of in situ monitoring. Herein, we engineered in vitro cancer cell models using breast cancer cells (MCF-7 and MDA-MB-231 cells) as the reprehensive cells on polyacrylamide (PA) gels with three stiffness, mimicking different developmental stages of cancer. We in situ characterized the functional activity of MRP1 and investigated the effect of ECM stiffness on MRP1 of cancer cells before and after vincristine treatment using scanning electrochemical microscopy (SECM) with ferrocenecarboxylic acid (FcCOOH) as the redox mediator and endogenous glutathione (GSH) as the indicator. The SECM results show that the functional activity of MRP1 is enhanced with increasing ECM stiffness, and the MRP1-mediated vincristine efflux activity of MCF-7 cells is more affected by ECM stiffness than that of MDA-MB-231 cells. This work, for the first time, applied SECM to in situ and quantitatively monitor the functional activity of MRP1 in cancer cells in different tumor mechanical microenvironments, which could help to elucidate the mechanism of matrix stiffness-dependent drug resistance behavior in cancer cells.

SECM using FcCOOH as the redox mediator and endogenous GSH as the indicator was employed to investigate the effect of extracellular matrix stiffness on the functional activity of MRP1 in cancer cells in situ.