Applied Biochemistry and Biotechnology最新文献

The indiscriminate use of antibiotics can disrupt the gut microbiota, and recent studies provide growing evidence for the critical role of the gut-brain axis in sustaining neurological health. This study investigated the antibacterial, neurobehavioral, and biochemical effects of five commonly used antibiotics, namely, amoxicillin, azithromycin, ciprofloxacin, rifampicin, and oxytetracycline. The neuroprotective function of the probiotic E.coli Nissle 1917 (EcN1917) was studied in vivo using zebrafish exposed to various antibiotics. Systematic behavioral analysis revealed that the antibiotics significantly impaired zebrafish behavior, while EcN1917 administration improved these behavioral deficits. The histopathological, oxidative stress and inflammatory marker analyses confirmed that antibiotics treatment caused significant damage to the zebrafish brain tissue, which was substantially mitigated following the administration of EcN1917. To demonstrate that the neuroprotective effect of EcN1917 could be mediated through strengthening of the gut-brain axis via the preservation of gut microbiota, we employed Lactobacillus rhamnosus (L. rhamnosus), a well-characterized gut microbe known for producing neuroactive compounds such as GABA, serotonin, and dopamine, as a representative commensal for the in vitro analysis. The results obtained indicate that EcN1917 promotes the survival of L. rhamnosus during antibiotic challenge. These findings suggest that EcN1917 has promising therapeutic potential to mitigate antibiotic‑induced neurotoxicity, possibly by promoting the survival of commensal bacteria in the gut and thereby influencing brain neurochemical balance possibly through gut-brain axis.

Cisplatin is mainly used for treating terminal hepatocellular carcinoma (HCC), but the development of drug resistance limits its clinical efficacy in treating this disease. The helicase activity of DDX11 can prevent hypersensitivity to chemotherapy drugs and DNA damage. The aim of this study was to explore the potential molecular mechanism through which DDX11 mediates cisplatin resistance in HCC. HepG2 and Huh7 cisplatin-resistant strains were established and named HepG2-DDP and Huh7-DDP, respectively. Cell proliferation and DNA damage were measured by CCK-8, colony formation and comet assays, and the expression of related proteins and genes was detected by Western blotting, immunohistochemistry, immunofluorescence and RT‒qPCR. The HepG2-DDP and Huh7-DDP cell lines were xenografted subcutaneously into nude mice to investigate the role of DDX11 in vivo. DDX11 expression was upregulated in HCC clinical samples and cell lines. DDX11 knockdown inhibited HCC cell proliferation and promoted sensitivity to cisplatin, DNA damage and endoplasmic reticulum (ER) stress, and SKP2 knockdown weakened the effects of DDX11 overexpression and promoted cisplatin-induced ER stress. Mechanistically, DDX11 inhibited cisplatin-induced DNA damage and ER stress by upregulating SKP2 expression, ultimately reducing the sensitivity of HCC cells to cisplatin. This study revealed that the DDX11/SKP2 axis may be a promising therapeutic target for improving resistance to cisplatin in patients with HCC.

Plant-based therapeutics are of immense importance in modern drug discovery owing to their multi-targeted mechanisms and favourable safety profiles. Among these, Petroselinum crispum has long been utilised in traditional medicine, yet remains underexplored for its potential against liver fibrosis, a progressive condition lacking effective antifibrotic therapies. In this study, a comprehensive computational strategy was employed to systematically investigate the hepatoprotective potential of P. crispum metabolites. A total of 177 phytochemicals from P. crispum were screened based on drug-likeness properties, while 10,014 liver fibrosis-associated genes were retrieved from established databases. Integration of compound-target predictions with disease-related gene sets identified key overlapping inflammatory mediators. Network pharmacology analysis, followed by molecular docking and dynamics simulations, revealed CXCL8, IL1B, and CSF2 as central targets potentially modulated by P. crispum flavonoids, apigenin and luteolin. The findings demonstrated stable binding interactions, supported by favourable binding energies. Although apigenin's interaction with IL1B has been reported in inflammatory conditions, its specific modulatory role on CXCL8 and CSF2 within the context of liver fibrosis remains unexplored. Notably, to the best of our knowledge, this is the first study to demonstrate that luteolin stably interacts with all three targets in the context of hepatic fibrosis. These findings highlight the polypharmacological nature of these flavonoids in modulating multiple cytokine-driven signaling pathways for the therapeutic repositioning of P. crispum constituents in chronic liver disease.

ε-Poly-L-lysine (ε-PL) is a L-lysine homopolymer with wide applications in the fields of food, cosmetics, and pharmaceuticals due to its excellent antimicrobial properties and biodegradability. It is primarily produced through microbial fermentation by Streptomyces species, with its biosynthesis catalyzed by the membrane-bound enzyme ε-PL synthetase (Pls). However, Pls purification from industrial strains has not been achieved, and its enzymatic properties, particularly the effects of metal ions on its activity, remain insufficiently characterized. To address this gap, we successfully expressed, purified, and characterized full-length Pls from the industrial strain Streptomyces albulus GS114 for the first time, achieving milligram-scale yields of high-purity protein. A systematic evaluation of His-tag length and position revealed their impact on recombinant membrane protein expression and purification. To improve purification efficiency, we developed a novel strategy integrating DEAE anion exchange chromatography with Ni-affinity chromatography, enabling efficient Pls isolation. Preliminary enzymatic assays showed that Pls exhibits optimal activity at 20 °C and pH 8.5. Both Mn²⁺ and Mg²⁺ effectively support Pls catalytic activity, marking the first report on the impact of metal ions on Pls activity. These findings lay the foundation for further research on enzyme engineering, biosynthetic mechanisms, and potential improvements in ε-PL biomanufacturing.

The present investigation aims to synthesis calcium oxide nanoparticles (CaO NPs) by extract of Ficus religiosa bark using calcium nitrate as a precursor via eco-friendly and simple method. The synthesized CaO NPs were characterized with the help of UV-Vis spectrophotometer, Fourier transform infrared (FTIR) spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and Thermo Gravimetric Analysis (TGA). The cytotoxicity of as synthesized CaO NPs was determined by MTT assay on L929 fibroblast cell lines. Wound scratch assay was performed to find the wound healing potential of as synthesized CaO NPs. Furthermore, the antibacterial activity of as synthesized CaO NPs was studied using agar well diffusion method. The effective synthesis of CaO NPs was performed using the bark extract of F. religiosa as a capping and reducing agents. The formation of CaO NPs was proved by UV-Vis spectrophotometer analysis, where the spectrum displayed absorption peaks at 224 nm and 248 nm. XRD pattern, SEM image and EDX spectrum revealed the formation of crystalline nature, spherical shape with average particle size of 50 nm and high purity CaO NPs. TGA spectrum confirmed the occurrence of 30% weight loss in CaO NPs. Anti-bacterial assay showed a high inhibition against Bacillus subtilis. MTT assay revealed that 20 µg of CaO NPs had less cytotoxicity (9.83%) while 100 µg of CaO NPs had 24.9% of cytotoxicity. CaO NPs held potent wound healing properties in the L929 cell lines. The study concludes that the synthesized CaO NPs are less toxic and possess wound healing potency. The green synthesized CaO NPs have significant biomedical applications including inhibit the microbial infections and could be used to formulate a new wound healing drug.

Spironolactone (SPR), a widely used potassium-sparing diuretic, frequently causes hyperkalemia, leading to significant cardiovascular and neurological complications. Taurine, a semi-essential amino acid with known antioxidant and neuroprotective effects, was hypothesized to mitigate these adverse effects. This study investigated taurine's efficacy against SPR-induced hyperkalemia and associated cognitive dysfunction in a rat model. Adult male Sprague-Dawley rats were treated for four weeks with SPR, SPR + galantamine (an AChE inhibitor widely used in the treatment of Alzheimer's disease), or SPR + varying concentrations of taurine, followed by assessment of cognitive, biochemical, and histopathological alterations. SPR administration significantly increased serum potassium levels (~7.5 mEq/L), induced cognitive deficits, disrupted neurotransmitter balance (e.g., altered GABA and glutamate levels), and caused reactive astrocytic swelling in key brain regions. Taurine demonstrated a dose-dependent protective effect against SPR-induced neurotoxicity by mitigating hyperkalemia and associated cognitive impairments. Biochemically, taurine restored neurotransmitter balance by increasing GABA and reducing the excitotoxic glutamate levels. Histological analysis further confirmed taurine's neuroprotective effects, showing preserved cortical structures and reduced astrogliosis, especially at the highest concentration (5%). Our correlation analysis reveals complex regulatory mechanisms underlying neurotransmitter balance in the brain. These findings suggest taurine as a promising therapeutic agent for alleviating SPR-induced neurological side effects. Further studies are needed to explore taurine's long-term effects and clinical applications in managing hyperkalemia-related cognitive dysfunctions.

Oxidative stress-induced vascular smooth muscle cell (VSMC) apoptosis plays a central role in aortic aneurysm (AA) progression. In this study, we developed N, Ce-codoped carbon dots (N, Ce-CDs, ~ 4.8 nm) as an efficient nanozyme to counteract this process. The synthesized N, Ce-CDs exhibited superior •OH radical scavenging capability and excellent biocompatibility. In vitro, N, Ce-CDs showed no cytotoxicity toward MOVAS cells, maintaining over 90% cell viability after 72 h exposure. More importantly, they demonstrated a significant protective effect against H₂O₂-induced oxidative damage. The nanozymes alleviated oxidative damage by scavenging intracellular reactive oxygen species (ROS), suppressing lipid peroxidation, and boosting endogenous antioxidant capacity through elevated levels of glutathione (GSH) and enhanced activities of superoxide dismutase (SOD) and catalase (CAT). Furthermore, N,Ce-CDs ‌significantly mitigated H₂O₂-induced damage, recovering ~ 60% of the lost mitochondrial membrane potential (MMP) and reducing the apoptosis rate from 31.97% to 18.52%. These findings highlight the potential of N, Ce-CDs as a multifunctional nanotherapeutic agent that protects VSMCs by integrating antioxidant defense with mitochondrial stabilization, presenting a novel strategy for AA treatment.