Bioscience, Biotechnology, and Biochemistry最新文献

Multiple roles of the evolutionarily conserved histone variant H2A.Z in development have been proposed. However, conventional H2A.Z knockouts cause embryonic lethality. Here, we developed a transient depletion system for H2A.Z in Caenorhabditis elegans using an auxin-inducible degron and demonstrated its contribution to germline differentiation at early developmental stages. This system can be applied to investigate temporal protein functions during development.

The white-spotted longicorn beetle (Anoplophora malasiaca), a serious fruit tree pest, relies on contact sex pheromones for mating purposes. The asymmetric synthesis of the pheromonal components, (+)-gomadalactones A and (-)-B, was achieved using an improved enantioselective version of our previous racemic synthesis method. The key 3-oxabicyclo[3.3.0]octane framework was constructed using a combination of Vassilikogiannakis one-pot, photodriven cyclopentenone synthesis with DBU-mediated lactonization. The enantioselective synthesis was enabled by Sharpless asymmetric dihydroxylation of the starting material, propenylfuran. The route, consisting of 15 steps, is significantly shorter than the previously reported asymmetric synthesis and provides concise and stereochemically reliable access to these biologically important diterpenoid pheromones.

Bacterial membrane vesicles (MVs) are nanosized lipid bilayer particles (20-400 nm) that package proteins, lipids, nucleic acids, and metabolites derived from parent cells. MVs are now recognized as actively produced structures that play crucial roles in bacterial physiology and host-microbe interactions. Both Gram-negative and Gram-positive bacteria, including commensals and pathogens in the gut, release MVs that mediate communication, gene transfer, and immunomodulation. This mini review summarizes recent advances in understanding MV biogenesis and function, with an emphasis on gut bacterial MVs. We outline two biogenetic pathways, lysis-associated and non-lytic routes, and discuss regulatory mechanisms, including environmental cues that modulate MV release. Furthermore, we highlight emerging evidence that gut bacterial MVs influence host immunity, barrier function, and disease pathogenesis, while also serving as promising vaccine platforms and diagnostic biomarkers.

Bacillus species have been employed as biocontrol agents in the context of plant disease management. However, the precise mechanisms through which they function remain to be fully elucidated. Cyclic lipopeptides (cLPs) have been deduced to play key roles in the biological control of plant diseases using Bacillus strains. In the early stages of research, the hypothesis was put forward that cLPs could suppress diseases through their antimicrobial activity. However, recent research provides robust evidence that cLPs function primarily as elicitors by inducing disease resistance in host plants. This review introduces recent trends regarding the characteristics of Bacillus cLPs in the context of biological control against plant diseases.

Chemotaxis enables bacteria to move toward favorable compounds via chemoreceptors. CtaA and CtaB are amino acid chemoreceptors in Pseudomonas protegens CHA0, and their ligand-binding domains show high sequence similarity. However, CtaA exhibits broad specificity, recognizing all 20 naturally occurring l-amino acids as ligands, whereas CtaB senses only four. This study aimed to investigate residues determining ligand specificity using site-directed mutagenesis and in silico analyses. Chemotaxis assays with heterologously complemented strains revealed that the D146A mutation in CtaA completely eliminated its ability to recognize ligands, whereas the A144D mutation in CtaB, corresponding to D146 in CtaA, enabled it to recognize new ligands while abolishing its original specificity. Hence, the residue at position 144 is a key determinant of CtaB specificity. Structural and docking analyses further suggested that other residues, including G99/F97 and I111/Q109 (CtaA and CtaB, respectively), may also contribute to differences in ligand specificity between CtaA and CtaB.

Monoclonal antibodies are essential tools in biological research, diagnostics, and therapeutics. While mammalian expression systems are widely used, microbial hosts such as Escherichia coli offer cost-effective and scalable production of antibody fragments but often yield inclusion bodies requiring refolding. In this study, we report a combined strategy using a translation-enhancing SKIK peptide tag and a leucine zipper-fused Fab format to improve expression in Escherichia coli, together with a continuous, dialysis-based automated refolding system. Compared with the conventional stepwise method, the automated process recovered model antibodies with equivalent antigen-binding activity and refolding yield (approximately 98%), while reducing processing time to 40%, waste volume to 69%, and chemical consumption to 47% of the modified stepwise process. The apparatus is simple to set up and operate, making it applicable from laboratory to industrial scales. This resource-efficient and scalable approach provides a practical alternative for scalable antibody fragment production in microbial systems.

Vitamin B12 is primarily present in animal-derived foods and is scarce in plant-derived foods; therefore, vegetarians and vegans are at risk of deficiency. Although furu, a traditional Chinese fermented tofu product, has been reported to contain vitamin B12, it remains unclear whether the vitamin B12 compounds present are bioactive or inactive. In this study, the vitamin B12 content of eight commercial furu products was quantified using high-performance liquid chromatography. Grey furu showed the highest level (∼1.1 μg/100 g), whereas the others contained < 0.4 μg/100 g. Liquid chromatography-tandem mass spectrometry revealed that only ∼9% of the total vitamin B12 in grey furu was bioactive, with most identified as inactive corrinoids. Other products showed similar profiles. These findings indicate that commercial furu products are not reliable sources of vitamin B12, although grey furu may supply a modest amount of bioactive vitamin B12.

Arsenic (As(III)), a toxic metalloid, binds strongly to cysteine thiols and induces protein misfolding and aggregation. Recent studies-mainly using Escherichia coli-have revealed how As(III)-induced aggregation occurs in cells and how this process can be exploited to design As(III)-responsive proteins. This mini-review highlights two strategies based on As(III)-triggered structural transitions. The quorum-sensing regulator LuxR undergoes As(III)-dependent aggregation that switches its transcriptional activity from ON to OFF, establishing the first aggregation-based whole-cell sensor and revealing an intracellular As(III) threshold required for switching. Inspired by this mechanism, the cysteine-free repressor BetI was rationally engineered to gain As(III) responsiveness through cysteine introduction, enabling As(III)-induced conformational activation. These findings demonstrate that As(III)-induced aggregation, once considered purely toxic, provides a foundation for developing proteins with controllable structural and functional switching.

Osteoarthritis (OA) is a degenerative joint disease characterized by chronic inflammation, oxidative stress, and cartilage degradation. Recent studies suggest that ferroptosis, an iron-dependent form of regulated cell death, may contribute to OA pathogenesis. In this study, we performed transcriptomic analysis using publicly available synovial tissue data from OA patients. The results revealed a consistent downregulation of key ferroptosis-inhibitory genes (GPX4, FTH1, SLC7A11) and upregulation of NCOA4, a critical mediator of ferritinophagy. These findings suggest that ferroptosis and oxidative stress are actively involved in the molecular landscape of OA synovium. Gene expression patterns also indicated elevated oxidative stress and inflammation, reflected by the upregulation of proinflammatory cytokines and matrix metalloproteinases. Taken together, our results highlight NCOA4-mediated ferroptosis as a potential contributor to OA development and suggest that targeting ferroptosis pathways may offer novel therapeutic strategies for OA.

Medium-chain aldehydes are important precursors of alkanes, which could be used as a biofuel. In this study, we screened 1300 microorganisms-including bacteria (including actinomycetes), yeasts, molds, and basidiomycetes-for their ability to produce tetradecanal from tetradecanoic acid. Among these microorganisms, Klebsiella pneumoniae subsp. pneumoniae NBRC3321 exhibited the highest 1-tetradecanol-producing activity from tetradecanoic acid. This strain was therefore selected as a suitable candidate for aldehyde-producing enzyme analysis. A novel aldehyde-producing acyl-CoA reductase gene (acrI) was isolated from K. pneumoniae subsp. pneumoniae NBRC3321, which comprises 1404 bp encoding a polypeptide of 49.1 kDa. His6-tagged AcrI requires NADH as a coenzyme to convert tetradecanoyl-CoA into tetradecanal. The enzyme catalyzed both acyl-CoA reduction and aldehyde hydrogenation, producing alcohol with acyl-CoA substrates of C6-C12, whereas it catalyzed acyl-CoA reduction producing only aldehydes with acyl-CoA substrates of C14-C16.