Yulong Yin

Aptamer-Based Sensing with Fluorescent Light-Up DNA.

DNA aptamers are widely used in the construction of fluorescent sensors, typically employing labelled fluorophores as signaling indicators. However, this covalent labeling approach suffers from several limitations, including complex and costly chemical modification, incompatibility with long aptamer sequences, and susceptibility to false-positive signals. To address these limitations, we constructed a novel aptamer-based fluorescent sensor using Lettuce indicator, a light-up DNA aptamer that adopts a precise three-dimensional structure, which enables it to selectively bind and activate the otherwise non-fluorescent small-molecule fluorophores. In our design, we destabilized Lettuce by fusing it with a target-binding aptamer via a transducer sequence. Upon target binding, structural rearrangement is triggered through the transducer, leading to the folding of Lettuce and restoration of its ability to activate the fluorophore, generating a target-dependent fluorescent signal. Through systematic optimization of the transducer and target-binding aptamer sequences, we created sensors for diverse targets, including small molecules, proteins, and metal ions. These sensors exhibit high signal-to-noise ratios, sensitivity and selectivity, and a wide dynamic range. As a proof-of-concept demonstration, a paper-based test strip for cost-effective and rapid detection of small molecule mycotoxins was developed. This versatile design provides a generalizable platform for the development of aptamer-based sensors, opening the way for future detection of diverse analytes.

Hemoglobin from Hermetia illucens exerts antibacterial activity by targeting bacterial membranes.

Drug-resistant bacteria pose an escalating threat to global public health, underscoring the urgent need for novel antibacterial agents. Natural green control strategies offer sustainable solutions against environmental pathogenic bacterial infections. Among them, natural antibacterial molecules derived from eukaryotic sources are undoubtedly the most compelling, owing to their safety, biocompatibility and resistance to drug resistance. The black soldier fly (Hermetia illucens, BSF) is recognized as a valuable reservoir of antibacterial factors due to its exceptional resistance to dense microbial environments. In this study, three previously uncharacterized antibacterial proteins were systematically identified from black soldier fly larvae (BSFL) using high-performance liquid chromatography-mass spectrometry (HPLC-MS). Hemoglobin (Hb) exhibited the strongest antibacterial activity in vitro, with low cytotoxicity, thermal stability, and acid resistance. Mechanistic analyses indicate that Hb compromises bacterial cell membrane integrity via biofilm disruption and direct membrane interaction, leading to nucleic acid and protein leakage, increased intracellular reactive oxygen species (ROS), and impairment of ATP-dependent energy metabolism. Furthermore, HiHb was structurally predicted to target intracellular components, including DNA topoisomerase and ribosomal proteins. Together, these multi-target effects accelerate bacterial cell death. Notably, ectopic expression of Hb markedly enhanced antibacterial ability in silkworms, suggesting that its antibacterial function is transferable across species. These findings highlight Hb derived from BSFL as a potent antibacterial protein, offering a promising resource for the development of novel therapeutics against bacterial infections and reduce the application of harmful bactericide.

Analysis of genetic structure and genetic diversity in Diannan small-ear pig.