Bioscience, Biotechnology, and Biochemistry最新文献

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.

The mitotic kinesin Eg5, essential for bipolar spindle formation, is a promising anticancer target. Eg5 features an unusually long loop L5, and specific inhibitors bind to a hydrophobic pocket formed by L5 and the α2/α3 helices, thereby blocking its function. We investigated the nematode kinesin BMK-1, which has a comparably long L5. Caenorhabditis elegans provides an advantageous model for evaluating in vivo effects of kinesin inhibitors. Here, we expressed BMK-1, characterized its biochemical properties, and examined its response to the Eg5-specific inhibitor S-trityl-L-cysteine (STLC). STLC inhibited both ATPase and motility of BMK-1, though less potently than Eg5. An L5-shortened BMK-1 mutant, with loop length reduced to that of conventional kinesins, lost STLC sensitivity while retaining microtubule-stimulated ATPase activity. These findings indicate that BMK-1 and Eg5 share an L5-dependent inhibition mechanism and suggest that Eg5 inhibitors may be applicable to investigating the physiological role of BMK-1 in C. elegans.

Rising global demand for food has led to excessive use of chemical fertilizers and pesticides, increasing yields but damaging soils, biodiversity, and microbial communities. Alternatives such as the application of beneficial bacteria could restore diminished soil health and maintain productivity without these long-term costs. Bacillus species and related genera, such as Paenibacillus and Priestia, combine several useful traits, including phosphorus solubilization, nitrogen fixation, production of growth hormones, enzyme release, and generation of antimicrobial compounds. These abilities improve nutrient use, protect plants from pathogens, and increase stress tolerance. Applied as single strains or in microbial consortia, they have consistently increased yields, improved soil health, and reduced reliance on synthetic agrochemicals. Continued work on strain optimization, consortia design and modeling, and adaptation to specific environments will further unlock their potential for sustainable agriculture.

Enhancing enzymatic reaction rates is essential for industrial applications; however, increasing catalytic efficiency (kcat/Km) through protein modification remains challenging due to the interdependence of kcat and Km. This review summarizes recent experimental and theoretical advances to improve enzymatic reaction rates by optimizing, rather than minimizing, Km. This concept originated from the Sabatier principle in artificial catalysis, which states that optimal catalytic activity occurs at an intermediate binding strength. When enzymes exhibit a trade-off between large kcat and small Km, the Km values that maximize reaction rates change depending on the substrate concentration. Although how much the optimum Km shifts depends on enzymes, the existence of an optimal Km that maximizes activity is expected to be applicable to a broad range of enzymes. We also discuss potential strategies to enhance kcat without altering Km by breaking their trade-off.

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.

Deoxycholic acid (DCA), a representative secondary bile acid, is produced by specific gut bacteria through bile acid 7α-dehydroxylation of cholic acid, catalyzed by enzymes encoded in the bai gene operon. Exploration of diversity and functional characteristics of DCA-producing bacteria is crucial for understanding the "in vivo" mechanisms of DCA production in the human intestine. Here, we have identified and characterized two strains derived from human feces as a novel DCA-producing species, Dorea ammoniilytica. These strains harbored segmented bai gene operons in their complete genome sequences and showed high DCA production activity from cholic acid in the culture experiments. Biochemical, phylogenetic, and average nucleotide identity analyses categorized them as D. ammoniilytica, which belongs to a distinct lineage from other known DCA producers and Dorea species. These findings expand the diversity of secondary bile acid-producing bacteria in the human gut microbiota and provide clues for clarifying the in vivo DCA production mechanisms.

Gts1 is a pleiotropic regulator for stress response and metabolism in yeast. Here, we identified and characterized CbGTS1 from the methylotrophic yeast Candida boidinii. Deletion of CbGTS1 reduced yeast proliferation on plant leaves and decreased tolerance to high-salt stress. These findings demonstrate that CbGts1 contributes to yeast adaptation and survival under challenging phyllosphere environments.

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 base-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.

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, and 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.

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.