Bioscience, Biotechnology, and Biochemistry最新文献

Ferritin, a protein ubiquitously found in living organisms, is well known for its major role in iron homeostasis. However, recent studies in invertebrates have revealed that it possesses diverse physiological functions beyond iron homeostasis. Especially in mollusks, ferritin has been suggested to be involved in functions such as restricting iron availability to pathogens during immune responses, mediating iron transport to specific tissues via hemolymph, and contributing to the formation of mineralized tissues, such as shells and radulae. Furthermore, it has been demonstrated that mollusks possess not only the cytoplasmic ferritin found in vertebrates, but also a secretory ferritin, which contains a signal peptide. This review provides a comprehensive overview of molluscan ferritin, summarizing the broad aspects of its molecular structure and physiological functions.

Carbonic anhydrase accelerates the hydration of carbon dioxide (CO₂) and is an attractive biocatalyst for carbon capture and utilization. Acinetobacter sp. Tol 5 shows high adhesiveness via its cell-surface protein AtaA. We previously demonstrated its application to bacterial immobilization and gas-phase bioproduction. Here, we developed Tol 5 cells expressing carbonic anhydrase and evaluated CO₂ conversion ability as whole-cell biocatalysts. A codon-optimized carbonic anhydrase from Sulfurihydrogenibium yellowstonense (SyCA) was produced in the cytoplasm, but the cells showed little activity as a whole-cell biocatalyst. To enhance activity, we fused six signal peptides (SPs) to SyCA for periplasmic expression. The Omp38-SP fusion of SyCA was properly processed to the mature size, yielding higher whole-cell activity. By contrast, the other constructs were either undetectable or remained unprocessed, resulting in lower activities. These results show that periplasmic expression of SyCA is important for efficient CO₂ hydration in Tol 5 cells as whole-cell biocatalysts.

Bifidobacteria are Gram-positive, anaerobic bacteria known for their health-promoting effects. However, a comprehensive analysis of middle- and long-chain fatty acids in bifidobacteria remains elusive. This study aimed to evaluate fatty acid accumulation among 43 strains covering 40 species/subspecies, and to elucidate interspecies and interstrain variations. Analysis of their cell-associated fatty acids revealed significant differences in total fatty acid levels. Bifidobacterium thermacidophilum and related species exhibited notably high accumulation of multiple fatty acids (eg decanoic acid, cis-7-C16:1). Among Bifidobacterium breve strains, M-16V produced significantly more cis-7-C16:1 than the others. Additionally, a homology analysis targeting cyclopropane fatty acid synthase was performed to determine the genetic basis of cis-9,10-methyleneoctadecanoic acid (cyclo-C19:0) production. Only strains possessing the homolog produced cyclo-C19:0. These results highlight substantial variation in fatty acid accumulation among bifidobacteria, which could influence their probiotic functionalities. This study provides a foundation for future research on the health benefits of bifidobacterial fatty acid profiles.

Inulin, a soluble dietary fiber, is widely recognized for its gut health benefits; however, its role in the progression of ulcerative colitis remains unclear. In this study, we investigated the effects of inulin supplementation on colitis induced by administering dextran sodium sulfate (DSS) to BALB/c mice. Mice were fed diets containing 10% inulin or cellulose, followed by administration of 2% DSS in drinking water. Inulin-supplemented mice exhibited a higher disease activity index and more severe epithelial damage compared to cellulose-fed controls. Similar pathological features were observed in mice administered polyethylene glycol to induce osmotic diarrhea, suggesting that increased luminal osmotic pressure may exacerbate colitis. Notably, co-administration of polycarbophil calcium with inulin ameliorated clinical symptoms and attenuated tissue damage. These findings suggest that inulin may aggravate colitis, potentially through increased luminal osmotic pressure. Therefore, managing osmotic diarrhea may represent a therapeutic strategy to mitigate colitis symptoms associated with certain dietary fibers.

Amniotic fluid (AF) constitutes a dynamic environment containing diverse bioactive molecules derived from both maternal and fetal sources that support fetal development. As the fetus develops in continuous contact with AF, it is plausible that AF influences the formation of the skin epidermis. However, the mechanisms through which AF promotes keratinocyte differentiation remain largely unclear. Here, we showed that goat AF enhanced the expression of key functional proteins involved in epidermal barrier formation, including small proline-rich proteins, loricrin, and transglutaminase. We further obtained the bioactive fractions that promote the expression of these differentiation-related proteins through multistep protein fractionation via column chromatography. Proteomic analysis subsequently revealed 291 candidate proteins, including 85 distinct extracellular proteins, primarily grouped into calcium-binding proteins, proteases and their regulators, extracellular matrix components, and signaling molecules. Collectively, these results suggest that proteins secreted or released into AF contribute to establishing a microenvironment conducive to epidermal differentiation.

This study aimed to elucidate the functions of saline-alkaline inducible genes encoding OsCHX11 and OsCHX16, members of the cation/H+ exchanger (CHX) family, under different component of saline-alkaline conditions. Rice biomass under carbonate-based (50 mm Na+ with carbonates) and high-pH (50 mm Na+ without carbonates) conditions was similar, whereas higher Na+/K+ ratio was observed under carbonate-based conditions. Under carbonate-based conditions, only OsCHX16 was significantly expressed, whereas both OsCHX11 and OsCHX16 were highly expressed under high pH conditions. The yeast complementation assay showed that OsCHX11 and OsCHX16 improved the yeast growth under saline, carbonate-based, and high-pH conditions by increasing K+ concentration. Taken together, these results suggest that OsCHX11 and OsCHX16 may contribute to the K+ uptake system under saline-alkaline conditions with or without carbonates at cell level.

Co-administration of histidine and soy isoflavones induced beige adipogenesis in male rats, as demonstrated by the formation of multilocular lipid droplets and increased uncoupling protein 1 gene expression in white adipose tissue. This response was accompanied by fat depot-specific enhancement of mitochondrial activity and suppression of lipogenesis, suggesting the potential for dietary strategies to combat obesity via beige adipocytes activation.

The taste of agricultural products and foods is an important factor in quality evaluation; thus, comparable taste data are useful for their production, marketing, branding, and distribution regardless of when or where the data were obtained. To realize this concept, taste data need to be standardized. In this study, a method for standardizing the sourness and sweetness intensities of apple was established using a taste sensor system and a standard solution prepared from citric acid and sucrose. These taste substances are commonly used for standard solutions of other foods. Polyphenolic compounds that interfere with the sweetness sensor probe were removed from sample solutions using polyvinylpolypyrrolidone. The taste intensities estimated using this method showed good agreement with chemical analysis values highly correlated with human sensory evaluation data.

Selaginellin A (Sela A), a derivative from Selaginella tamariscina, exerts antitriple-negative breast cancer effects in MDA-MB-231 cells. Proteomic profiling identified 1136 differentially expressed proteins after Sela A treatment, predominantly downregulated (n = 889). Enrichment analyses revealed that Sela A significantly downregulated pathways critical for DNA repair, replication, and cell cycle progression, while upregulating ribosomal biogenesis and protein processing. Mechanistically, Sela A acts as a PTP1B inhibitor (IC50 = 7.4 μm), binding key residues (PHE-182, GLU-186). This inhibition activates the mechanistic target of rapamycin complex 1 (mTOR). Consequently, mTOR activation stimulates ribosomal synthesis but concurrently triggers a p70S6K-mediated negative feedback loop, degrading IRS1. IRS1 loss suppresses Akt signaling, reducing expression of cell cycle proteins and inducing G1-phase arrest. Thus, Sela A may block MDA-MB-231 cell proliferation via PTP1B inhibition driving mTOR/IRS1/Akt dysregulation.

Glucagon dysregulation is a hallmark of type 2 diabetes mellitus (T2DM), yet its early hepatic effects remain unclear. Here, we demonstrate that glucagon-induced gluconeogenesis is markedly enhanced in primary hepatocytes from prediabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a well-established model of human T2DM. Compared to control LETO rats, OLETF hepatocytes showed significantly higher glucagon-stimulated expression of gluconeogenic genes (Pepck, G6pase, and Fbp1) at both mRNA and protein levels, along with elevated glucose production. Notably, mRNA decay analysis revealed prolonged half-lives of gluconeogenic transcripts in OLETF hepatocytes, indicating enhanced mRNA stability as a novel mechanism contributing to increased hepatic glucose output. These findings highlight aberrant glucagon responsiveness and posttranscriptional regulation as potential predisposing factors in genetically susceptible models prior to the onset of overt metabolic abnormality, which may be of interest for preventive or therapeutic strategies for controlling fasting hyperglycemia.