Broadband Multidimensional Spectroscopy Identifies the Amide II Vibrations in Silkworm Films

We used two-dimensional infrared spectroscopy to disentangle the broad infrared band in the amide II vibrational regions of Bombyx mori native silk films, identifying the single amide II modes and correlating them to specific secondary structure. Amide I and amide II modes have a strong vibrational coupling, which manifests as cross-peaks in 2D infrared spectra with frequencies determined by both the amide I and amide II frequencies of the same secondary structure. By cross referencing with well-known amide I assignments, we determined that the amide II (N-H) absorbs at around 1552 and at 1530 cm^–1 for helical and β-sheet structures, respectively. We also observed a peak at 1517 cm⁻¹ that could not be easily assigned to an amide II mode, and instead we tentatively assigned it to a Tyrosine sidechain. These results stand in contrast with previous findings from linear infrared spectroscopy, highlighting the ability of multidimensional spectroscopy for untangling convoluted spectra, and suggesting the need for caution when assigning silk amide II spectra.     

A Box–Behnken Extraction Design and Hepatoprotective Effect of Isolated Eupalitin-3-O-β-D-Galactopyranoside from Boerhavia diffusa Linn.

The objectives of this study were to optimize and quantify the maximum percentage yield of eupalitin-3-O-β-D-galactopyranosidefrom Boerhavia diffusa leaves using response surface methodology (RSM), as well as to demonstrate the hepatoprotective benefits of the bioactive compound. The Box–Behnken experimental design was utilized to optimize the eupalitin-3-O-β-D-galactopyranoside extraction procedure, which also looked at the extraction duration, temperature, and solvent concentration as independent variables. Boerhaviadiffusa leaves were extracted, and n-hexane, chloroform, ethyl acetate, and water were used to fractionate the dried extracts. The dried ethyl acetate fraction was thoroughly mixed in hot methanol and stored overnight in the refrigerator. The cold methanol was filtered, the solid was separated, and hot methanol was used many times to re-crystallize the solid to obtain pure eupalitin-3-O-β-D-galactopyranoside (0.1578% w/w). The proposed HPTLC method for the validation and quantification of eupalitin-3-O-β-D-galactopyranosidewassuccessfully validated and developed. The linearity (R₂ = 0.994), detection limit (30 ng), and quantification limit (100 ng) of the method, as well as its range (100–5000 ng), inter and intraday precision (0.67% and 0.991% RSD), specificity, and accuracy (99.78% RSD), were all validated as satisfactory. The separation of the eupalitin-3-O-β-D-galactopyranoside band was achieved on an HPTLC plate using toluene:acetone:water (5:15:1 v/v) as a developing system. The Box–Behnken statistical design was used to determine the best optimization method, which was found to be extraction time (90 min), temperature (45 °C), and solvent ratio (80% methanol in water v/v) for eupalitin-3-O-β-D-galactopyranoside. Standard silymarin ranged from 80.2% at 100 µg/mL to 86.94% at 500 µg/mL in terms of significant high hepatoprotection (cell induced with carbon tetrachloride 0.1%), whereas isolated eupalitin-3-O-β-D-galactopyranoside ranged from 62.62% at 500 µg/mL to 70.23% at 1000 µg/mL. More recently, it is a source of structurally unique flavonoid compounds that may offer opportunities for developing novel semi-synthetic molecules.     

The Role and Regulation of Thromboxane A2 Signaling in Cancer-Trojan Horses and Misdirection

Over the last two decades, there has been an increasing awareness of the role of eicosanoids in the development and progression of several types of cancer, including breast, prostate, lung, and colorectal cancers. Several processes involved in cancer development, such as cell growth, migration, and angiogenesis, are regulated by the arachidonic acid derivative thromboxane A₂ (TXA₂). Higher levels of circulating TXA₂ are observed in patients with multiple cancers, and this is accompanied by overexpression of TXA₂ synthase (TBXAS1, TXA₂S) and/or TXA₂ receptors (TBXA2R, TP). Overexpression of TXA₂S or TP in tumor cells is generally associated with poor prognosis, reduced survival, and metastatic disease. However, the role of TXA₂ signaling in the stroma during oncogenesis has been underappreciated. TXA₂ signaling regulates the tumor microenvironment by modulating angiogenic potential, tumor ECM stiffness, and host immune response. Moreover, the by-products of TXA₂S are highly mutagenic and oncogenic, adding to the overall phenotype where TXA₂ synthesis promotes tumor formation at various levels. The stability of synthetic enzymes and receptors in this pathway in most cancers (with few mutations reported) suggests that TXA₂ signaling is a viable target for adjunct therapy in various tumors to reduce immune evasion, primary tumor growth, and metastasis.     

A Unique,Porous C3N4 Nanotube for Electrochemiluminescence with High Emission Intensity and Long-Term Stability: The Role of Calcination Atmosphere

Developing excellent strategies to optimize the electrochemiluminescence (ECL) performance of C₃N₄ materials remains a challenge due to the electrode passivation, causing weak and unstable light emission. A strategy of controlling the calcination atmosphere was proposed to improve the ECL performance of C₃N₄ nanotubes. Interestingly, we found that calcination atmosphere played a key role in specific surface area, pore-size and crystallinity of C₃N₄ nanotubes. The C₃N₄ nanotubes prepared in the Air atmosphere (C₃N₄ NT-Air) possess a larger specific surface area, smaller pore-size and better crystallinity, which is crucial to improve ECL properties. Therefore, more C₃N₄^•− excitons could be produced on C₃N₄ NT-Air, reacting with the SO₄^•− during the electrochemical reaction, which can greatly increase the ECL signal. Furthermore, when C₃N₄ nanotube/K₂S₂O₈ system is proposed as a sensing platform, it offers a high sensitivity, and good selectivity for the detection of Cu²⁺, with a wide linear range of 0.25 nM~1000 nM and a low detection limit of 0.08 nM.     

Pllans–II Induces Cell Death in Cervical Cancer Squamous Epithelial Cells via Unfolded Protein Accumulation and Endoplasmic Reticulum Stress

Due to the lack of chemotherapeutic drugs that selectively affect cervical cancer cells, natural sources such as snake venom are currently being investigated for molecules with antitumor potential. Pllans–II, a phospholipase A₂ type–Asp49 from Porthidium lansbergii lansbergii snake venom, induced cell death in a cervical cancer cell line—Ca Ski—related to dysfunction in the ability to resolve endoplasmic reticulum stress, evidenced by sub–expression of genes such as PERK, ERO1 PDIs, HSP70, and CHOP. Western blot analysis validated the last two genes′ sub–expression at the protein level. In addition, Pllans–II presented a dose–dependent cytotoxic effect on cancer cells and an insignificant effect on healthy endothelial cells (HUVEC). Additionally, Pllans–II inhibited cancer cells′ adhesion and migration capacity, induced cell cycle arrest in the G2/M phase, and induced apoptosis stimulated possibly by the extrinsic route. These results demonstrate for the first time that Pllans–II has an antitumor effect on a squamous epithelial cervical cancer cell line and represents a possible biotechnological tool for designing a prominent antitumor agent.     

Photocatalytic Degradation of Dyes Using Titania Nanoparticles Supported in Metal-Organic Materials Based on Iron

Composite materials based on titania nanoparticles (TiO₂ NPs) and three metal-organic frameworks (MOFs) called MIL-53 (Fe) ((Fe (III) (OH) (1,4-BDC)), MILs (Materials Institute Lavoisier)), MIL-100 (Fe) (Fe₃O(H₂O)₂OH(BTC)₂), and Fe-BTC (iron-benzenetricarboxylate) with different percentages of TiO₂ NPs (0.5, 1, and 2.5% wt.) were synthesized using the solvothermal method and used as photocatalytic materials in the degradation of two dyes (Orange II and Reactive Black 5 (RB5)). The pristine and composite materials were characterized with X-ray diffraction, Raman, UV–Vis and Fourier transform infrared spectroscopy and scanning electron microscopy techniques. The 2.5TiO₂/MIL-100 composite material showed the best results for the degradation of both dyes (Reactive Black 5 and Orange II dye, 99% and 99.5% degradation in 105 and 150 min, respectively). The incorporation of TiO₂ NPs into MOFs can decrease the recombination of the change carrier in the MOF, increasing the photocatalytic activity of a pristine MOF. Results therefore indicated that the synthesized MOF nanocomposites have good potential for wastewater treatment.     

Effect of Sex Steroids and PGF2α on the Expression of Their Receptors and Decorin in Bovine Caruncular Epithelial Cells in Early–Mid Pregnancy

Changes in the expression of various genes, including pregnancy-associated hormone receptors and extracellular matrix proteins, have been suggested to play a significant role in bovine placental development. This study aimed to examine the influence of sex steroids and PGF_2α on decorin (DCN) expression in the epithelial cells of bovine caruncle in early–mid pregnancy in cows. The expression patterns of DCN, PTGFR_, PGR and ESR1 were analyzed by RT-qPCR and Western blotting in primary caruncular epithelial cell cultures (PCECC) and placental tissue homogenates derived from the 2nd and 4th months of pregnancy. PCECC were found to express DCN, PTGFR_, PGR and ESR1. The intensity of PGR staining was higher in cells derived from the 4th month of pregnancy (p < 0.05). The 17β-estradiol, progesterone and PGF_2α have not been shown to affect DCN expression. PGF_2α decreased PTGFR expression in cells derived from the 4th month of gestation (p < 0.05). In conclusion, the results of the present preliminary study showed that the expression of the PTGFR, ESR1, PGR and DCN in PCECC does not vary throughout early–mid pregnancy. Further studies should be carried out to observe the relationship between hormonal status and cellular adhesion to determine their importance for properly developing placentation and pregnancy in cows.     

Carbon Dioxide Adsorption over Activated Carbons Produced from Molasses Using H2SO4, H3PO4, HCl,NaOH, and KOH as Activating Agents

Cost-effective activated carbons for CO₂ adsorption were developed from molasses using H₂SO₄, H₃PO₄, HCl, NaOH, and KOH as activating agents. At the temperature of 0 °C and a pressure of 1 bar, CO₂ adsorption equal to 5.18 mmol/g was achieved over activated carbon obtained by KOH activation. The excellent CO₂ adsorption of M-KOH can be attributed to its high microporosity. However, activated carbon prepared using HCl showed quite high CO₂ adsorption while having very low microporosity. The absence of acid species on the surface promotes CO₂ adsorption over M-HCl. The pore size ranges that are important for CO₂ adsorption at different temperatures were estimated. The higher the adsorption temperature, the more crucial smaller pores were. For 1 bar pressure and temperatures of 0, 10, 20, and 30 °C, the most important were pores equal and below: 0.733, 0.733, 0.679, and 0.536 nm, respectively.     

Development of a GC/Q-ToF-MS Method Coupled with Headspace Solid-Phase Microextraction to Evaluate the In Vitro Metabolism of β-Caryophyllene

Sample preparation remains both a challenging and time-consuming process in the field of bioanalytical chemistry. Many traditional techniques often require multi-step processes, which can introduce additional errors to the analytical method. Given the complexity of many biological matrices, thorough analyte extraction presents a major challenge to researchers. In the present study, a headspace solid-phase microextraction (HS-SPME) coupled with a GC/Q-ToF-MS method, was developed to quantify in vitro metabolism of β-caryophyllene by both human liver microsome (HLM) and S9 liver fractions. Validation of the method was demonstrated both in terms of linearity (R² = 0.9948) and sensitivity with a limit of detection of 3 ng/mL and a limit of quantitation of 10 ng/mL. In addition, the method also demonstrated both inter- and intra-day precision with the relative standard deviation (RSD) being less than 10% with four concentrations ranging from 50–500 ng/mL. Since this method requires no solvents and minimal sample preparation, it provides a rapid and economical alternative to traditional extraction techniques. The method also eliminates the need to remove salts or buffers, which are commonly present in biological matrices. Although this method was developed to quantify in vitro metabolism of one analyte, it could easily be adapted to detect or quantify numerous volatiles and/or semi-volatiles found in biological matrices.     

“One-Pot” CuCl2-Mediated Condensation/C–S Bond Coupling Reactions to Synthesize Dibenzothiazepines by Bi-Functional-Reagent N,N′-Dimethylethane-1,2-Diamine

The efficient “One-pot” CuCl₂-catalyzed C–S bond coupling reactions were developed for the synthesis of dibenzo[b,f][1,4]thiazepines and 11-methy-ldibenzo[b,f][1,4]thiazepines via 2-iodobenzaldehydes/2-iodoacetophenones with 2-aminobenzenethiols/2,2′-disulfanediyldianilines by using bifunctional-reagent N, N′-dimethylethane-1,2-diamine (DMEDA), which worked as ligand and reductant. The reactions were compatible with a range of substrates to give the corresponding products in moderate to excellent yields.