Abstract The western flower thrips, Frankliniella occidentalis, poses a serious threat to global agriculture because of its feeding damage and virus transmission. Its major aggregation pheromone component neryl (S)-2-methylbutanoate (NMB) is a strong attractant for adult females. However, the molecular mechanisms underlying NMB detection, particularly the role of odorant-binding proteins, remain poorly defined. This study identified and functionally characterized FoccOBP56h as a key mediator of the behavioral response to NMB. qRT-PCR showed that FoccOBP56h is predominantly expressed in the antennae and is significantly upregulated following NMB exposure. Fluorescence binding assays revealed that recombinant FoccOBP56h exhibited high affinity for NMB. Molecular docking and site-directed mutagenesis indicated that Asn90, Met104, and Val105 are important for NMB binding. RNAi-mediated knockdown of FoccOBP56h significantly reduced female attraction to NMB. These findings identify FoccOBP56h as a promising molecular target involved in NMB detection, providing a foundation for developing semiochemical-based strategies for insect behavior manipulation in pest management.
Abstract Caffeic acid, a natural phenolic acid with antioxidant and antibacterial properties, is a high-quality natural additive widely used in various food processing. In this study, the probioticEscherichia coliNissle 1917 was selected as the host for producing caffeic acid. First, the competitive branch of the precursor l-tyrosine was blocked, resulting in the mutant strain WNZ05. Then, the quorum sensing system was introduced into WNZ05 to dynamically supply l-tyrosine, which was used as a switch plasmid to coordinate the expression of FjTAL, hpaBC, and ycjP. The SAM5 gene was also introduced to reduce the intermediate products p-coumaric acid, achieving efficient flow of the metabolic pathway toward caffeic acid. Ultimately, the engineered strain produced 1.87 g/L caffeic acid in shake flasks and a record 13.92 g/L via fed-batch fermentation in a 2.5 L bioreactor, the highest microbial yield reported to date.
Abstract Protoporphyrinogen IX oxidase (PPO) is a validated target for fast-acting herbicides. To identify low-dose PPO-inhibiting leads, 41 benzyl-substituted pyrimidinedione derivatives were designed by side-chain optimization of epyrifenacil and synthesized. In greenhouse postemergence screening, FM-604 provided 100% control of Zinnia elegans and Abutilon theophrasti and 80–85% control of Setaria glauca and Echinochloa crus-galli at the lowest rate tested (2.34 g a.i./ha). FM-604 inhibited Nicotiana tabacum PPO with an IC50 of 21.46 nM versus 30.29 nM for epyrifenacil. Docking and 100 ns molecular dynamics simulations suggested a stable binding mode involving Arg98, Asn67, and Phe392, while DFT calculations indicated a comparatively small HOMO–LUMO gap. These results identify FM-604 as a PPO-inhibiting lead for further optimization and evaluation.
Abstract Naturally abundant flavonoids inhibit α-glucosidase (α-GLU), but the mechanisms underlying the synergistic effects among key active compounds remain poorly understood. In this study, the synergistic inhibition of α-GLU by hyperin, isoquercitrin, and quercetin was systematically investigated using fluorescence quenching, isothermal titration calorimetry, circular dichroism, differential scanning calorimetry, computational models, and Caco-2 cell assays. The ternary combination synergistically inhibited α-GLU (IC50 = 0.022 mg/mL, combination index <1) and showed the greatest α-helix reduction and denaturation temperature decrease of α-GLU. Molecular docking and molecular dynamics simulations suggested that quercetin preferentially occupied the hydrophobic catalytic pocket, whereas hyperin and isoquercitrin primarily interacted with peripheral regions. In differentiated Caco-2 cells, hyperin and isoquercitrin exhibited stronger inhibition toward sucrase than maltase, whereas quercetin showed the opposite trend. Collectively, the results demonstrate that the synergistic inhibition of α-GLU arises from complementary binding modes, cooperative conformational perturbation, and differential targeting of intestinal disaccharidase activities.
Abstract 5-aminolevulinic acid (5-ALA) is a naturally occurring, metabolically active non-proteinogenic amino acid that serves as a key precursor for the biosynthesis of heme, chlorophyll, and vitamin B12. Due to its high biological activity and versatile physiological functions, 5-ALA has been widely applied in agriculture, medicine, and other sectors. With the rapid advances in metabolic engineering and synthetic biology, microbial cell factories have been developed as promising platforms for the efficient production of 5-ALA. This review summarizes recent progress in biosynthetic pathways and metabolic engineering strategies for enhancing 5-ALA production. First, the metabolic routes involved in 5-ALA biosynthesis are outlined. Subsequently, recent advances in engineering approaches, including enzyme engineering, pathway optimization, and cellular engineering, are highlighted. Finally, current challenges and future prospects for sustainable 5-ALA production are discussed. Overall, this review provides valuable insights to guide the rational design and optimization of microbial platforms for enhanced 5-ALA biosynthesis.
