Bioscience, Biotechnology, and Biochemistry最新文献

Osteoarthritis (OA) is a progressive joint disorder characterized by inflammation and metabolic imbalance. Schisandrin A (Sch-A), a bioactive compound from Schisandra sphenanthera, is known for its anti-inflammatory and protective properties. This study investigated the effects of Sch-A on chondrocyte senescence and metabolism using IL-1β-stimulated CHON-001 cells as an in vitro OA model. Sch-A showed no cytotoxicity up to 100 μM and alleviated IL-1β-induced chondrocyte injury. It restored anabolic metabolism, suppressed catabolic activity, and reduced inflammatory and fibrotic responses. Bioinformatics indicated links between Sch-A, cellular senescence, and the PI3K/Akt pathway. Functional assays confirmed that Sch-A suppressed senescence-associated secretory phenotype (SASP) factors, senescence markers, SA-β-galactosidase activity, and PI3K/Akt activation, while PI3K inhibition enhanced its anti-senescent effects. These findings suggest that Sch-A mitigates chondrocyte senescence and metabolic dysregulation by modulating PI3K/Akt signaling, supporting its therapeutic potential for OA.

We prepared nanovesicles (NVs) derived from broccoli using ultracentrifugation and evaluated their anti-inflammatory properties. Two distinct NV populations were isolated as precipitates from broccoli homogenates following centrifugation at 20 000 × g and 200 000 × g. These NVs contained RNAs, proteins, isothiocyanates, and chlorophylls. Dynamic light scattering analysis confirmed their nanoscale size. The NVs were internalized by RAW264 cells and significantly inhibited nitric oxide production and NF-κB pathway activation under lipopolysaccharide (LPS) stimulation. Comprehensive analysis of inflammatory cytokine expression revealed strong suppression of interleukin-6 (IL-6) by both NV types, which was further validated by ELISA. Additionally, interleukin-1β and tumor necrosis factor-α production were also reduced. Notably, the anti-inflammatory effects were partially attributed to small RNAs (<200 nt) present within the NVs. Collectively, these findings suggest that broccoli-derived NVs possess potent anti-inflammatory activity.

This study aimed to determine the changes in polyphenols associated with autumn coloration of Acer palmatum leaves. A. palmatum leaves harvested in July (before autumn coloration: BAC) and November (after autumn coloration: AAC) were boiled in water. The AAC extract showed higher antioxidant activity than the BAC extract in assays measuring DPPH radical scavenging and superoxide dismutase-like activity. High-performance liquid chromatography analysis showed that the two extracts exhibited similar peak patterns for major polyphenols, with AAC extract exhibiting a large peak for compound I. After the two extracts were fractionated, the compound I-rich fraction (AAC Fr. 2) showed the strongest antioxidant activity among the obtained fractions. Finally, compound I was identified as mallotinic acid by liquid chromatography-mass spectrometry and nuclear magnetic resonance analyses. Our study revealed that the antioxidant activity of A. palmatum leaves is enhanced and mallotinic acid is accumulated during autumn coloration.

A simple one-pot and biomimetic synthetic method for producing pimeforazine A and B, fluorescent benzoxazines with neuroprotective activity isolated from the olive weevil Pimelocerus perforatus, was developed. This synthesis uses the oxidation of commercially available 4-(2-hydroxyethyl)phenol (tyrosol) with 2-iodoxybenzoic acid (IBX), followed by the addition of concentrated aqueous ammonia. The reaction produced pimeforazines A and B in a ratio of 3.4:1, which is consistent with the natural product ratio. This method provides a practical and efficient alternative to extracting these compounds from the olive weevil.

Gordonia sp. strain TY-5 utilizes propane, but not methane, as the sole carbon source. In this strain, propane is oxidized to 2-propanol by propane monooxygenase (Prm), and 2-propanol is further metabolized to methyl acetate, which is subsequently converted into acetate and methanol. However, methane and methanol metabolism in strain TY-5 has remained unclear. In this study, draft genome analysis revealed that strain TY-5 possesses the one-carbon (C1) dissimilation pathway, in which methanol is oxidized to CO2, but lacks a C1 assimilation pathway, suggesting that methanol is not utilized as the carbon source but is used as an energy source. Furthermore, we found that strain TY-5 can oxidize methane by Prm. Gene disruption analysis revealed that N, N-dimethyl-4-nitrosoaniline-dependent methanol dehydrogenase contributes to methanol oxidation in strain TY-5. Our findings provide new insights into the physiological significance of C1 and hydrocarbon metabolism for adapting the natural environment where methane and propane coexist.

In RAW264 macrophages, demethyltorosaflavone C (DTFC)-luteolin derivative from Cassia nomame-suppressed lipopolysaccharide-induced nitric oxide production without cytotoxicity. DTFC exhibited no nitric oxide radical scavenging activity but downregulated inducible nitric oxide synthase and cyclooxygenase-2 at protein and mRNA levels, indicating anti-inflammatory effects through pathways similar to those of luteolin. These results suggest that DTFC appears to have potential comparable to luteolin.

Sugar transporter SWEETs play diverse roles in plants. To assess the role of SWEETs in floral thermogenesis, we analyzed Symplocarpus renifolius SWEET2, SWEET4, and SWEET6, whose mRNA expression increased from the prethermogenic to thermogenic stages in RNA-seq data. Yeast complementation using hexose transport-deficient strains showed that SrSWEET4 and SrSWEET6 transport both glucose and fructose; SrSWEET4 also transports galactose. SrSWEET2 did not complement hexose transport deficiency in the yeast. Intracellular localization of GFP-tagged proteins in S. renifolius leaf protoplasts revealed that SrSWEET4 and SrSWEET6 localize to the plasma membrane, whereas SrSWEET2 may localize to the tonoplast. In qPCR, SrSWEET4 and SrSWEET6 exhibited prominent organ-specific expression in the spadix, particularly in the stamen, whereas SrSWEET2 was not differentially expressed at any stage or organ. In situ localization of SrSWEET6 mRNA was detected in developing pollen. These results suggest that SrSWEET4 and SrSWEET6 are involved in stamen development via hexose transport during thermogenesis.

In skeletal muscle cells, the resting membrane potential is primarily determined by Cl-, necessitating precise regulation of intracellular and extracellular Cl- balance. Potassium chloride cotransporters (KCCs), members of the cation-chloride cotransporter superfamily, facilitate the efflux of K+ and Cl- at a 1:1 ratio. However, the specific roles of KCCs in skeletal muscle remain poorly understood. In this study, we investigated the function of KCCs in skeletal muscle cells using [(dihydroindenyl)oxy]acetic acid (DIOA), a KCCs inhibitor. DIOA treatment of cultured C2C12 myotubes impaired contractility in response to electrical pulse stimulation. Additionally, DIOA-treated myotubes exhibited muscle atrophy, accompanied by increased expression of atrogenes such as Atrogin-1 and MuRF1. These findings reveal a novel role for KCCs in skeletal muscle and provide insights that may contribute to the development of preventive or therapeutic strategies for muscle disorders and atrophy.

The Aspergillus ustus pigment production was investigated by introducing different precursor and enzyme inhibitors during the early biosynthesis stages. A comparative transcriptomic analysis was conducted between pigment-producing and non-producing A. ustus strains. Bioinformatics approaches were employed to functionally annotate and perform enrichment analysis of the sequenced genes. Reverse transcription quantitative PCR (RT-qPCR) was used to validate the transcriptome sequencing results. The addition of acetic acid, propionic acid, isoleucine, arginine, methionine and phenylalanine enhanced pigment production, whereas iodoacetamide, dinitrofluorobenzene, P-aminobenzoic acid and imidazole inhibited it. Transcriptomic analysis revealed significant differential gene expression during pigment biosynthesis, including pronounced upregulation of genes related to non-reducing polyketide synthase (NR-PKS). Integrative evidence reveals that A. ustus pigment is synthesized via an iterative type I PKS pathway catalyzed by fungal NR-PKSs, similar to the noranthrone biosynthetic pathway in fungi. RT-qPCR validation showed 80% concordance with the RNA-seq data, confirming the reliability of the transcriptome sequencing.

The skin tubercle gland of the stonefish Synanceia verrucosa secretes ichthyocrinotoxin. Ichthyocrinotoxins have been suggested to act as antifeedants against predators. Brominated natural products, namely synanceins D (4) and E (5), were newly isolated and characterized from the ichthyocrinotoxin of S. verrucosa. Synanceins D (4) and E (5) exhibited strong bitterness at 10 μg in the bitterness detection test. This was similar to synanceins A-C (1-3), previously isolated as the major components of the ichthyocrinotoxin from S. verrucosa. Furthermore, synanceins A-E (1-5) were evaluated for their growth-inhibitory activities against the parasitic protozoan Leishmania major. Among them, synancein C (3) exhibited the highest antileishmanial activity, showing 90.5% inhibition at a concentration of 100 μg/mL.