Eumelanin, a natural biological pigment formed by the polymerization of 5,6-dihydroxyindole and its carboxylic acid derivatives, is ubiquitous in animals and microorganisms. Its highly conjugated molecular structure confers multiple functional properties, including broad-spectrum light absorption, antioxidant activity, free radical scavenging, and metal ion chelation, making it a promising material for applications in biomedicine, functional coatings, and environmental remediation. The conventional production of eumelanin relies largely on extraction from animal tissue or chemical synthesis, which are constrained by limited raw materials and uncontrollable product structures. Recently, microbial cell factory-based biosynthesis of eumelanin has attracted increasing attention due to its environmental sustainability and structural controllability. This review comprehensively summarizes the biosynthetic pathways, strategies for metabolic engineering and genetic engineering, analysis and characterization methods for eumelanin, and discusses future perspectives for the application and development of microbial eumelanin production.

Ulcerative colitis (UC) is a chronic non-specific intestinal inflammatory disease with complex pathogenesis. Recent studies have identified a pivotal role of the gut microbiota in the etiology of the disease. Beneficial bacteria, such as Lactobacillus and Bifidobacterium, have been shown to regulate the balance of the gut microbiota, repair the mucosal barrier, and alleviate inflammation. In contrast, excessive proliferation or secretion of toxins by harmful bacteria, such as Escherichia, can damage the integrity of the mucosa, induce inflammation, and accelerate the progression of UC. The active ingredients of traditional Chinese medicine, such as Scutellariae radix polysaccharides, pulchinenosides, and ginsenoside Rg1, may offer a promising avenue for the treatment of UC by modulating the structure of the gut microbiota and enhancing the barrier function and mucosal integrity. The present article reviews the latest research progress in the regulation mechanism of the gut microbiota in UC and the traditional Chinese medicine intervention, with a view to providing new strategies and theoretical support for clinical treatment.

Medicinal plants and microorganisms engage in complex, dynamic interactions that profoundly influence plant growth and development, the biosynthesis of secondary metabolites, resistance to pathogens, and adaptation to environmental stressors. Therefore, elucidating the chemical signaling molecules that mediate these interactions is of fundamental importance. The review systematically summarizes the types and functional mechanisms of chemical signals involved in medicinal plant-microorganism interactions. It highlights the roles of both plant- and microorganism-derived signaling molecules in shaping the rhizosphere microbial community assembly, regulating plant growth, and modulating the accumulation of bioactive secondary metabolites. In addition, we discuss the functional divergence of bidirectional signaling in both symbiotic and competitive interactions. Although many mechanism aspects of these chemical signals remain to be fully elucidated, current knowledge provides a solid framework for understanding their regulatory roles. With a “signal-microbiome-function” framework, it is possible to manipulate plant chemical signaling or screen functional microbial strains to reconstruct beneficial rhizosphere microbiomes. Such strategies hold potential for improving soil-plant-microorganism interactions, promoting plant growth, enhance the accumulation of medicinal compounds, and strengthen resistance to pathogens. Overall, these insights are of considerable significance for improving the quality of Chinese medicinal materials and promoting the sustainable and ecological cultivation of medicinal plants.

The continuous evolution and drug-resistant mutations of influenza virus have placed higher demands on the study of its pathogenic mechanism, as well as the development of antiviral drugs and vaccines. As a key tool for real-time monitoring of viral infection, replication and transmission, viral visualization reporter systems have evolved into various strategies, including high-resolution microscopic imaging, exogenous nanomaterial labeling, recombinant reporter viruses, and virus infection-inducible reporter systems. This manuscript systematically reviewed the research progress of influenza virus visualization technologies, elaborated the principles, core breakthroughs, and application scenarios of each technique, analyzed the common limitations and specific problems existing in the current technical system, and prospected its development direction combined with cutting-edge research, providing a reference for technical selection and innovative applications in influenza virus visualization research.