Gray mold caused by Botrytis cinerea is a destructive postharvest disease affecting numerous fruit and vegetable crops worldwide, including tomato fruits, and results in substantial economic losses. In this study, an antifungal actinomycete, Streptomyces sp. KRA20–350, was isolated and characterized as a potent producer of metabolites active against B. cinerea. Considering that the culture filtrate of KRA20–350 strongly inhibited mycelial growth and conidial germination of B. cinerea and effectively suppressed gray mold development on tomato fruits, bioassay-guided purification identified tautomycetin as one of the major antifungal metabolites produced by KRA20–350. Tautomycetin exhibited potent antifungal activity against B. cinerea, inhibiting mycelial growth and conidial germination with IC50 values of 5.9 and 10.6 μg mL–1, respectively, and completely prevented gray mold development on tomato fruits at concentrations above 15.6 μg mL–1. Preventive application of tautomycetin to tomato seedlings achieved 85–98% disease control efficacy, whereas curative treatment showed only limited activity. Consistently, fungal penetration into onion epidermal tissues was markedly inhibited by tautomycetin. Drug-induced haploinsufficiency screening in Schizosaccharomyces pombe, molecular docking analysis, and genetic manipulation of the putative target gene in B. cinerea suggested that RNA 5′-triphosphatase may be a putative cellular target associated with tautomycetin sensitivity. Collectively, these findings demonstrate that Streptomyces sp. KRA20–350 produces tautomycetin, an effective antifungal metabolite with strong preventive activity against gray mold, highlighting its potential application as a postharvest biocontrol agent for tomato disease management.
AB5 toxins constitute a major family of bacterial exotoxins. Their pathogenicity depends on the coordinated actions of two components: an enzymatically active A subunit and a pentameric B subunit. The B subunit mediates host cell recognition and intracellular trafficking. Among them, cholera toxin represents a representative model for investigating structure–function relationships governing toxin entry and delivery. While the catalytic activity of the A subunit has been extensively characterized, growing evidence indicates that pathogenic outcomes are critically shaped by trafficking strategies encoded within the B subunit pentamer. This review focuses on the cholera toxin B subunit (CTB) as a model system to elucidate how pentameric organization enables multivalent GM1 recognition, receptor clustering, and efficient intracellular transport. We summarize current knowledge on the molecular basis of CTB pentamerization, its thermodynamic and structural advantages, and the role of multivalency in amplifying delivery efficiency and pathogenicity. In addition, we examine how CTB-mediated intracellular trafficking influences uptake pathway selection and intracellular routing, thereby contributing to consistent and robust toxic outcomes. Beyond pathogenic mechanisms, we briefly discuss the potential implications of CTB-mediated trafficking for translational applications. By integrating structural, cellular, and functional perspectives, this review demonstrates how CTB-mediated mobility governs intracellular routing and uptake pathway selection. This framework provides a basis for understanding AB5 toxin pathogenicity and its broader biological significance.
Plastics play a pervasive role in contemporary society and serve a wide range of purposes. However, widespread accumulation of plastic waste has become a serious environmental concern. Traditional disposal techniques, such as incineration and landfill disposal, have exacerbated ecological problems, including air, water, and soil pollution. A crucial strategy for promoting sustainability is the adoption of biodegradable plastics as green alternatives to traditional plastics along with the implementation of mechanical and chemical recycling approaches. However, the recycling of biodegradable plastics remains understudied because of prevalent biases and misconceptions. This review aims to address this knowledge gap by assessing common misconceptions regarding biodegradable plastics and emphasizing the merits of their recyclability. Furthermore, this review explores the trends and methods for chemically recycling biodegradable plastics and highlights innovative practices. It endeavors to show that the environmental impact of accidental spills can be minimized by transitioning from a linear economy—focused on the disposal of biodegradable plastics—to a circular economy that emphasizes sustainable chemical recycling. The structural properties of biodegradable materials require less activation energy for decomposition than conventional plastics, facilitating effective chemical recycling. This review highlights the need to develop advanced recycling technologies and encourage further research and societal action to support the transition to a circular economy.
One-component (1 K) polyurethane clearcoats offer significant operational advantages over two-component (2 K) systems through simplified processing and extended shelf life, yet suffer from inferior mechanical performance due to inherent limitations in their crosslinking capabilities. Conventional 1 K systems rely solely on intermolecular crosslinking between segregated polyol and blocked isocyanate components, leading to heterogeneous crosslinker distribution, microphase separation, and ultimately compromised coating properties. To address these fundamental issues, we developed a unique self-crosslinkable prepolymer (SCP) incorporating both hydroxyl and blocked isocyanate functionalities within single polymer chains, enabling to produce a selfcrosslinkable polyurethane clearcoat (SC-PUP) upon heat. Our molecular architecture approach enables simultaneous intramolecular and intermolecular crosslinking mechanisms through dual reactions that minimizes crosslinking distance between functional groups and eliminates heterogeneity within the polymer matrix. The SC-PUP clearcoat containing SCP demonstrates enhanced performances, with higher storage modulus (5.08 x 105 Pa), glass transition temperature of 81.39 degrees C, and crosslinking density (2.02 x 10-3 mol/g) compared to the OC-PUP and PL-PUP clearcoats via intermolecular crosslinking. Surface hardness utilizing SC-PUP increased to 272.35 MPa with superior scratch resistance, while tensile strength showed improvement over the intermolecular crosslinking PU clearcoats. It is attributed to the formation of a uniformly dense crosslinking network structure with hydroxyl conversion efficiency based on SC-PUP, substantially exceeding the other clearcoats. The self-crosslinking approach successfully bridges the performance gap between 1 K and 2 K systems while maintaining processing simplicity, establishing a new paradigm for high-performance automotive clearcoat technology.
The catalytic upcycling of polyethylene (PE) remains a major challenge in sustainable waste management. This study demonstrates that water promotes PE hydrocracking over Ru/zeolite catalysts only when the support framework is strongly hydrophilic, as in HY and HMOR. Systematic characterization reveals that this promotional effect is governed by surface wettability, rather than acidity or metal dispersion. Thermodynamic analysis confirms that water and PE are immiscible under reaction conditions, ruling out direct water-polymer interactions. Instead, water preferentially associates with hydrophilic catalyst surfaces, promoting Br & oslash;nsted acid activity through confined hydration. Controlled experiments show that direct contact between water and the catalyst is essential for enhanced reactivity; spatial separation between the two leads to suppressed conversion, likely due to unfavorable interactions between water and the molten polymer. These findings highlight the mechanistic role of interfacial water-catalyst accessibility and establish catalyst hydrophilicity as a key design parameter for reliable and efficient water-assisted hydrocracking. The results have practical implications for processing moisture-containing plastic waste streams.
