Regulation of gene expression in the secondary metabolic synthesis pathway of Lonicera japonica Flos by yeast polysaccharides.

Lonicera japonica Flos is a valuable herb in the Lonicerae family. While transcriptomic studies on L. japonica have focused on different tissues (stems, leaves, flowers) or flowering stages, few have investigated the molecular mechanisms underlying chemical composition synthesis influenced by exogenous factors, such as foliar fertilization. Moreover, most transcriptomic studies on L. Japonica have been conducted on chlorogenic acid and luteoloside, and the molecular synthesis mechanism of the overall chemical composition has not been analyzed. Methods: We conducted a single-factor, four-level foliar fertilization experiment using yeast polysaccharides. Different yeast polysaccharides concentrations were sprayed on L. japonica for six consecutive days with dynamic sampling. High-performance liquid chromatography determined the active ingredients in each group. The two groups exhibiting the most significant differences were selected for transcriptomic analysis to identify key synthetic genes responsible for L. japonica's active ingredients. Key results: Principal component analysis conducted on samples collected on September 8 revealed significant differences in the active ingredient amounts between the 0.1 g/L yeast polysaccharides treatment group and the control group. Transcriptome sequencing analysis identified 218 significantly differentially expressed genes, including 60 upregulated and 158 downregulated genes. Twelve differential genes involved in the chemical components synthesis pathway of L. japonica under yeast polysaccharides treatment were identified: PAL1, PAL2, PAL3, 4CL1, 4CL, CHS1, CHS2, CHS, CHI1, CHI2, F3H, and SOH. Conclusions: This study contributes to the theoretical understanding of essential synthetic genes associated with L. japonica's active ingredients. It offers data support for further gene exploration and sheds light on the molecular mechanisms underlying L. japonica quality formation. These findings hold significant implications for enhancing the content of secondary metabolites of L. japonica. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-024-01482-1.

Understanding the AIE phenomenon of nonconjugated rhodamine derivatives via aggregation-induced molecular conformation change.

The bottom-up molecular science research paradigm has greatly propelled the advancement of materials science. However, some organic molecules can exhibit markedly different properties upon aggregation. Understanding the emergence of these properties and structure-property relationship has become a new research hotspot. In this work, by taking the unique closed-form rhodamines-based aggregation-induced emission (AIE) system as model compounds, we investigated their luminescent properties and the underlying mechanism deeply from a top-down viewpoint. Interestingly, the closed-form rhodamine-based AIE system did not display the expected emission behavior under high-viscosity or low-temperature conditions. Alternatively, we finally found that the molecular conformation change upon aggregation induced intramolecular charge transfer emission and played a significant role for the AIE phenomenon of these closed-form rhodamine derivatives. The application of these closed-form rhodamine-based AIE probe in food spoilage detection was also explored.

Recent progress and outlooks in rhodamine-based fluorescent probes for detection and imaging of reactive oxygen, nitrogen, and sulfur species.

Reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive sulfur species (RSS) serve as vital mediators essential for preserving intracellular redox homeostasis within the human body, thereby possessing significant implications across physiological and pathological domains. Nevertheless, deviations from normal levels of ROS, RNS, and RSS disturb redox homeostasis, leading to detrimental consequences that compromise bodily integrity. This disruption is closely linked to the onset of various human diseases, thereby posing a substantial threat to human health and survival. Small-molecule fluorescent probes exhibit considerable potential as analytical instruments for the monitoring of ROS, RNS, and RSS due to their exceptional sensitivity and selectivity, operational simplicity, non-invasiveness, localization capabilities, and ability to facilitate in situ optical signal generation for real-time dynamic analyte monitoring. Due to their distinctive transition from their spirocyclic form (non-fluorescent) to their ring-opened form (fluorescent), along with their exceptional light stability, broad wavelength range, high fluorescence quantum yield, and high extinction coefficient, rhodamine fluorophores have been extensively employed in the development of fluorescent probes. This review primarily concentrates on the investigation of fluorescent probes utilizing rhodamine dyes for ROS, RNS, and RSS detection from the perspective of different response groups since 2016. The scope of this review encompasses the design of probe structures, elucidation of response mechanisms, and exploration of biological applications.