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Heme is an important tetrapyrrole compound, and has been widely applied in food and medicine industries. Although microbial production of heme has been developed with metabolic engineering strategies during the past 20 years, the production levels are relatively low due to the multistep enzymatic processes and complicated regulatory mechanisms of microbes. Previous studies mainly adopted the strategies of strengthening precursor supply and product transportation to engineer microbes for improving heme biosynthesis. Few studies focused on the engineering and screening of efficient enzymes involved in heme biosynthesis. Herein, a growth-coupled, high-throughput selection platform based on the detoxification of Zinc-protoporphyrin IX (an analogue of heme) was developed and applied to directed evolution of coproporphyrin ferrochelatase, catalyzing the insertion of metal ions into porphyrin ring to generate heme or other tetrapyrrole compounds. A mutant with 3.03-fold increase in / was selected. Finally, growth-coupled directed evolution of another three key enzymes involved in heme biosynthesis was tested by using this selection platform. The growth-coupled selection platform developed here can be a simple and effective strategy for directed evolution of the enzymes involved in the biosynthesis of heme or other tetrapyrrole compounds.
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http://dx.doi.org/10.3389/fbioe.2023.1236118 | DOI Listing |
Nano Lett
September 2025
Department of Materials Science and Engineering, Seoul National University, Seoul 08826, South Korea.
Seamless integration of active devices into photonic integrated circuits remains a challenge due to the limited accessibility of the optical field in conventional waveguides, which tightly confine light within their cores. In this study, we propose a two-dimensional (2D) ultrathin waveguide as a photonic platform that enables efficient interaction between guided light and surface-mounted devices by supporting optical modes dominated by evanescent fields. We show that the guided light in a monolayer MoS film propagates over millimeter-scale distances with more than 99.
View Article and Find Full Text PDFBeilstein J Nanotechnol
August 2025
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada.
The preparation of multimodal nanoparticles by capping magnetic iron oxide nanoparticles (IONPs) with functional organic molecules is a major area of research for biomedical applications. Conjugation reactions, such as carbodiimide coupling and the highly selective class of reactions known as "click chemistry", have been instrumental in tailoring the ligand layers of IONPs to produce functional biomedical nanomaterials. However, few studies report the controls performed to determine if the loading of molecules onto IONPs is due to the proposed coupling reaction(s) employed, or some other unknown interaction with the IONP surface.
View Article and Find Full Text PDFAlpha Psychiatry
August 2025
College of Literature and Media, Wenzhou University of Technology, 325027 Wenzhou, Zhejiang, China.
Objective: Problematic internet use (PIU) is a general behavioral addiction and encompasses various syndromes. Previous research found that traumatic events may potentially influence or alter the propensity for PIU. This study aimed to explore the mediating role of fear of missing out (FOMO) and rumination in the influence of post-traumatic stress disorder (PTSD) on PIU among Wenchuan earthquake survivors.
View Article and Find Full Text PDFMikrochim Acta
September 2025
Hunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang, 421001, China.
An Ag-functionalized structural color hydrogel (Ag-SCH) sensor is constructed for colorimetric detection of glutathione (GSH). The hydrogel is prepared by using the coordination of Ag and 1-vinylimidazole (1-VI) as cross-linking network. GSH acts as a competitive ligand to break the coordination between Ag and 1-VI, leading to the expansion and structural color change of the hydrogel.
View Article and Find Full Text PDFMikrochim Acta
September 2025
Faculty of Science, Shenyang University of Chemical Technology, Shenyang, 110142, China.
A sensitive electrochemical glucose biosensor using ZrO₂@CNTs nanocomposite was developed for real-time metabolism monitoring for athletes. The nanocomposite was prepared by a simple ultrasound-assisted technique, and the glucose oxidase (GOx) was covalently immobilized to improve the biorecognition ability. CNTs treated with acid served as a highly conductive framework, and ZrO₂ nanoparticles can provide structural stability and catalytic performance, thus showing synergistic enhancement of electron transfer kinetics and enzyme loading capacity.
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