Bioscience, Biotechnology, and Biochemistry最新文献

Capsaicin and menthol, agonists of transient receptor potential channels, are known to influence energy metabolism. However, their roles in skeletal muscle function are unclear. Therefore, this study aimed to investigate the effects of capsaicin and menthol on skeletal muscle differentiation and muscle quality. In vitro, capsaicin and menthol increased myosin heavy chain (MYH)4 expression, while menthol upregulated MYH1. Both compounds reduced MYH2 and MYH7 levels. Additionally, capsaicin enhanced uncoupling protein (UCP)3 expression, and menthol increased UCP2, UCP3, and M-type creatine kinase. In vivo, topical application during voluntary running did not affect body or muscle mass, but capsaicin reduced fat mass and increased locomotor activity. Menthol enhanced light-phase activity. Both treatments elevated MYH4, UCP2, and UCP3 in muscle, and suppressed myostatin expression. These findings suggest capsaicin and menthol modulate skeletal muscle phenotype and metabolism through both direct cellular effects and increased physical activity.

Carbon catabolite repression (CCR) enables microorganisms to preferentially utilize energetically favorable carbon sources. In Aspergillus oryzae, the transcription factor CreA plays a central role in carbon source metabolism via CCR, although its function under various culture conditions remains insufficiently determined. In this study, we performed genomic systematic evolution of ligands via exponential enrichment-sequencing (gSELEX-Seq) using the DNA-binding domain of CreA to identify candidate CreA-binding regions within the genome. Motif analysis revealed a consensus binding site overlapping the previously reported 5'-SYGGRG-3' core. RNA-Seq analysis using the A. oryzae ΔcreA strain cultured under CCR release conditions revealed significant differences in the expression of 486 genes, including transporters, transcription factors, and sugar metabolism enzymes. Integration of gSELEX-Seq data and transcriptome profiles revealed nine candidate genes directly regulated by CreA. These findings enhance our understanding of the multifaceted regulatory network of CreA in A. oryzae, providing a framework for further functional studies.

Some fungi form fairy rings by secreting fairy chemicals that regulate plant growth. Among them, 2-azahypoxanthine (AHX) has been proposed as a new phytohormone, but its mechanisms remain unclear. We treated Arabidopsis thaliana with 400 μm AHX and observed growth inhibition, contrasting with earlier reports in bentgrass. To elucidate this effect, we performed transcriptome sequencing and identified differentially expressed genes. Gene ontology enrichment revealed activation of hormone- and stress-related terms and suppression of photosynthesis-related terms. Liquid chromatography-mass spectrometry further showed an increase in 1-aminocyclopropanecarboxylic acid, an ethylene precursor, after AHX treatment. These results suggest that AHX alters the stress response in A. thaliana by regulating genes associated with multiple plant hormones, including abscisic acid, ethylene, jasmonic acid, salicylic acid, and cytokinins.

Seafood processing wastewater, rich in organic carbon and nutrients, represents a potential low-cost medium for algal biomass cultivation. Here, we evaluated the growth performance of a naturally adapted microalgae-bacterial consortium isolated from a seafood processing facility primarily handling skipjack tuna. The consortium was cultured directly in raw wastewater without nutrient supplementation. Within 9 days, chlorophyll concentration increased fivefold and total suspended solids nearly doubled, indicating substantial biomass accumulation. Dissolved organic carbon and phosphate declined by 85% and 68%, respectively, indicating nutrient assimilation by the microbial community. The culture also showed a pH increase, consistent with active photosynthetic carbon uptake. Ammonium transiently accumulated before declining during algal growth, while nitrate remained low and nitrite undetectable, indicating a nitrogen cycle dominated by ammonium with minimal oxidation. These results demonstrate the feasibility of valorizing seafood wastewater for microalgal biomass production and provide a basis for sustainable, resource-oriented applications of industrial effluents.

Methylotrophs live symbiotically with plants in the phyllosphere. Because the leaf surface is a harsh environment with light, temperature, and low trophic levels, microorganisms on the leaves may have oligotrophic metabolism or use light energy to compensate for the low-carbon conditions for their growth. Various natural samples, including plants, have been screened for oligotrophic and/or light-driven methylotrophs.

Senescent cells contribute to tissue dysfunction and the progression of age-related diseases. Senolytic therapies, which selectively eliminate these cells, have demonstrated beneficial effects in preclinical models by restoring tissue function and delaying age-related decline. Naturally occurring compounds are gaining attention due to their structural diversity and low toxicity. Among these, triterpenes, plant-derived molecules with anti-inflammatory and protective properties, are emerging as therapeutic candidates for targeting cellular senescence. Here, we aimed to evaluate the senolytic activity of β-amyrin, a plant-derived triterpene, in established fibroblast models. Using senescent cells of murine and human origin, we found that β-amyrin selectively induced cell death in senescent cells. Mechanistic analyses suggest that this effect involves cannabinoid receptor 2 signaling and proceeds independently of caspase activation. These findings highlight β-amyrin as a promising senolytic compound with a potentially unique mechanism of action.

This clinical trial assessed the effect of mayonnaise on postprandial glycemic responses to rice. Fifteen Japanese men consumed 150 g of rice with or without 15 g of mayonnaise (designated RM and R dishes, respectively). Blood samples were collected at 0, 30, 45, 60, 90, and 120 min postconsumption to measure glucose, insulin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and free fatty acid (FFA) levels. Compared to the R dish, the RM dish significantly reduced Δglucose at 30 and 45 min and the incremental area under the curve (iAUC) and ΔCmax of glucose. However, no significant differences were observed in Δinsulin. Meanwhile, ΔGIP and ΔFFA from 30 to 120 min and ΔGLP-1 at 30 and 45 min were significantly higher following RM dish intake. The iAUC of GIP and GLP-1, and ΔCmax of GIP were also elevated. These results indicate that adding mayonnaise suppresses postprandial glucose elevation and enhances incretin secretion.

Chemotactic responses of Aurantiochytrium limacinum SR21 to 90 distinct compounds including sugars, organic acids, alcohols, amino acids, amines, aromatic compounds, sulfoxides, vitamins, nucleosides, and inorganic compounds were analyzed. While the zoospores were significantly attracted to several amino acids, they did not respond to their typical nutrients such as sugars or organic acids, suggesting that the chemotaxis may not be directly involved in the search for their nutrition. Zoospores were also attracted to vanillin, which is a component of lignin and a major component of land plant cell walls. This suggests that Aurantiochytrium sp. may be involved in the cycling of carbons in terrestrial plant biomass between land and sea via lignin. Structural comparisons of responding and nonresponding vanilloids indicated that the hydrocarbon chain at position 1, the alkoxyl group at position 3, and the hydroxyl group at position 4 may be particularly important in vanilloid recognition.

Diabetic nephropathy is a kidney disease aggravated by the uremic toxin indoxyl sulfate, which is produced from indole by the gut microbiota. Targeting the bacterial enzyme tryptophan indole-lyase (TIL), which produces indole from l-tryptophan, could be a promising therapeutic strategy. This study investigates diketopiperazines (DKPs), particularly cyclo-glycylproline [cyclo(Gly-Pro)], as potential TIL inhibitors. Cyclo(Gly-Pro) and other DKPs moderately inhibited indole production from l-tryptophan in crude bacterial extracts. Cyclo(Gly-Pro) was not metabolized by the bacteria and did not affect their viability. Cyclo(Gly-Pro) inhibited the Escherichia coli TIL with a Ki​ value of 17 μM through a mixed-type mechanism. Computational docking studies supported this finding, showing that cyclo(Gly-Pro) binds near the active site of TIL. Additionally, cyclo(Gly-Pro) significantly reduced indole production in bacterial cultures and human fecal samples. These findings suggest that cyclo(Gly-Pro) could be a promising dietary supplement or a lead compound for developing new therapeutics to prevent or treat diabetic nephropathy.

The intramolecular Diels-Alder reaction was employed for the assembly of the trans-decalin structure of cladoic acid, an anti-Trypanosoma cruzi active polyketide isolated from a fungus of the genus Cladosporium. Although the cycloaddition provided the desired trans-octalin as a minor product, the method was effective for simultaneously constructing four stereocenters in the B-ring of cladoic acid.