Bioscience, Biotechnology, and Biochemistry最新文献

Peptone is a promising raw material for culturing microorganisms and mammalian cells, but its composition remains unclear. Here, 36 different peptones were comprehensively quantified using five approaches: gas chromatography/tandem mass spectrometry, liquid chromatography/mass spectrometry, ion chromatography, post-column detection-high-performance liquid chromatography, and inductively coupled plasma mass spectrometry (named multimodal targeting analysis). Seventy-eight chemical compounds/ions were detected among 121 targets, including amino acids, nucleic acids, organic acids, sugars, vitamins, and minerals. The sum of the quantitated component weights exceeded 65% of the total weight in all cases (mean 88%). Principal component and cluster dendrogram analyses revealed clear distinctions between not only peptone brands but also production lots. Plant peptones exhibited greater variety than casein and meat peptones. Partial least squares analysis identified components specific to particular manufacturing processes and peptone sources. Acid-digested peptones contained more free amino acids, including Ala, Cys, Gly, Thr, Ser, Asp, Glu, and Pro, than enzyme-digested types.

Cells must recycle stalled ribosomes while preventing the accumulation of aberrant nascent chains. In bacteria, this is achieved by overlapping pathways with distinct substrates: ribosome-rescue systems act mainly on non-stop mRNAs, whereas ribosome-associated quality control (RQC) targets mid-ORF arrests. Work in Gram-positive bacteria defined an RQC mechanism that appends C-terminal degrons to stalled peptides, yet the full set of bacterial substrates and splitting factors remains unresolved, and enteric bacteria notably lack a canonical RQC elongation factor. This review traces the field from the discovery of tmRNA (also known as 10Sa RNA or SsrA RNA) through alternative rescue pathways to the current bacterial RQC framework. I summarize mechanisms across three layers-processing of 50S-peptidyl-tRNA, collision sensing and splitting, and downstream proteolysis-and compare species-level strategies and conservation patterns. I highlight how rescue and quality control intersect during phage infection, and outline key mechanistic uncertainties and experiments needed to resolve them.

Thrombopoietin (TPO) is essential for treating thrombocytopenia, but its clinical use is limited by immunogenicity and short half-life. TMP, a TPO mimetic peptide, addresses these issues but requires fusion with carriers to improve pharmacokinetics. This study developed ELP-TMP fusion proteins (ELP120-2TMP and 2TMP-ELP120) to extend half-life and enhance activity via elastin-like polypeptide (ELP). Results showed EC50 values of 5.81 nM for ELP120-2TMP and 10.88 nM for 2TMP-ELP120, compared to 2.65 nM for recombinant human TPO (rhTPO). At a dose of 600 nmol/kg, ELP120-2TMP resulted in peak platelet counts in mice on day 20, exhibiting a half-life of 22.9 h. Conversely, 2TMP-ELP120 achieved peak platelet counts on day 12, with a half-life of 25.4 h. The half-lives of both fusion proteins were significantly longer than that reported 2TMP alone (1 h). Area under the curve (AUC) indicated superior platelet stimulation over rhTPO (p < 0.01).

Acetic acid bacteria (AAB) produce phosphatidylcholine (PC) as a major membrane component. PC has long been considered important for acetic acid tolerance in AAB, yet direct experimental support remains limited, and its physiological roles under diverse environmental stresses are not well defined. In this study, we constructed PC-deficient mutants of Acetobacter pasteurianus by deleting the phosphatidylethanolamine N-methyltransferase gene. PC deficiency resulted in phosphatidylglycerol accumulation and a tendency toward acyl-chain shortening. Phenotypic analysis showed that PC deficiency impaired growth under ionic, heat, and acidic stresses, indicating that PC supports membrane integrity under these stress conditions. Heterologous expression of PC synthase from Pseudomonas aeruginosa enabled choline-dependent regulation of PC biosynthesis. This system revealed that even low PC levels are sufficient to restore normal growth and acetic acid fermentation. These findings suggest that PC has diverse physiological roles in AAB and its function does not necessarily depend on its abundance in the membrane.

Obesity is a growing global concern, and pancreatic lipase inhibitors have emerged as potential targets for anti-obesity strategies. This study evaluates the potential of Perilla frutescens (L.) Britton var. frutescens leaf tea as a pancreatic lipase inhibitor for managing dietary fat absorption. Perilla leaf tea significantly inhibited the pancreatic lipase-mediated hydrolysis of emulsified triglycerides, depending on its polyphenol and rosmarinic acid contents. However, the inhibitory effect diminished at higher concentrations, which coincided with the increased emulsion particle size. Perilla leaf tea did not inhibit the hydrolysis of solubilized p-nitrophenyl palmitate, whereas authentic rosmarinic acid reduced lipase activity against both substrate types. These findings suggest that perilla leaf tea and rosmarinic acid have different lipase inhibition mechanisms. This study implies that rosmarinic acid contributes to the lipase-inhibiting properties of perilla leaf tea and emulsion structure plays a pivotal role in modulating the ability of the tea to inhibit lipase activity.

The mammary circulatory system supports mammary growth and lactation by supplying oxygen and nutrients. Insulin-like growth factor 1 (IGF1) is essential for mammary gland development, yet its involvement in angiogenic regulation remains unclear. This study investigated whether IGF1 stimulates vascular endothelial growth factor (VEGF) production in mammary epithelial cells and explored the underlying signaling pathways. IGF1 increased VEGF mRNA expression in a bovine mammary epithelial cell line and in HC11 cells, and enhanced VEGF promoter activity and secretion in HC11 cells in a dose-dependent manner. Conditioned medium from IGF1-stimulated HC11 cells promoted tube formation in HUVECs, which was attenuated by a VEGFR inhibitor. IGF1 rapidly induced ERK1/2 and Akt phosphorylation, and inhibitors of these pathways suppressed VEGF secretion. These findings suggest that IGF1 upregulates VEGF via the MEK-ERK1/2 and PI3K-Akt pathways, thereby promoting mammary angiogenesis and contributing to mammary gland development and lactation efficiency.

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.