Evaluation of a biomarker (NO) dynamics in inflammatory zebrafish and periodontitis saliva samples via a fast-response and sensitive fluorescent probe.

Many pathological processes include nitric oxide (NO), a signaling transduction molecule. Tumors, cardiovascular, cerebrovascular, neurodegenerative, and other illnesses are linked to abnormal NO levels. Thus, evaluating NO levels in vitro and in vivo is crucial for studying chemical biology process of associated disorders. This work devised and manufactured a coumarin-based fluorescent probe ZPS-NO to detect nitric oxide (NO). The reaction between ZPS-NO and NO produced a highly selective and sensitive optical response that caused a powerful fluorescence "turn-on" effect with a ultra-low NO detection limit of 14.5 nM. Furthermore, the probe was applied to sense and image NO in living cells and inflammatory model of zebrafish, as well as to detect NO in periodontitis patients' saliva samples. We anticipate that probe ZPS-NO will serve as a practical and effective tool for assessing the interactions and evaluation of periodontitis development.

In vivo bioimaging and detection of endogenous hypochlorous acid in lysosome using a near-infrared fluorescent probe.

The phagocyte's lysosome is the primary site of hypochlorous acid (HOCl) synthesis, and HOCl can be used as a biomarker for osteoarthritis diagnosis and treatment evaluation. Accurate detection of HOCl with high sensitivity and selectivity is required to understand its activities in healthy bio-systems and diseases. By integrating acceptable design principles and dye screening methodologies, we proposed and developed a novel near-infrared fluorescent HOCl sensing probe (FNIR-HOCl). The FNIR-HOCl probe has a quick reaction rate, high sensitivity (LOD = 70 nM), and excellent selectivity toward HOCl over other metal ions and reactive oxygen species. It has been successfully implemented to detect endogenous HOCl produced by RAW264.7 cells, as well as in vivo imaging towards mice with osteoarthritis. As a result, the probe FNIR-HOCl is extremely promising as a biological tool for revealing the roles of HOCl in various physiological and pathological contexts.

A novel near-infrared fluorescent probe with hemicyanine scaffold for sensitive mitochondrial pH detection and mitophagy study.

Mitochondria, as an energy-producing powerhouse in live cells, is considered to be directly linked to cellular health. However, dysfunctional mitochondria and abnormal mitochondria pH would possibly activate mitophagy, cell apoptosis and intercellular acidification process. In this work, we synthesized a novel near infrared fluorescent probe (FNIR-pH) for measurement of mitochondrial pH based on the hemicyanine skeleton as a fluorophore. The FNIR-pH probe functioned as a mitochondrial pH substrate and exhibited quick and sensitive turn-on fluorescence responses to mitochondrial pH in basic solution due to the deprotonation of hydroxy group in the structure. From pH 3.0 to 10.0, the FNIR-pH exhibited almost 100-fold increase in fluorescence intensity at 766 nm wavelength. The FNIR-pH also displayed superior selectivity to various metal ions, excellent photostability, and low cytotoxicity, which facilitated further biological application. Owing to the proper pKa value of 7.2, the FNIR-pH paved the way for real-time monitoring of mitochondria pH changes in live cells and sensitive sensing of mitophagy. Moreover, the FNIR-pH probe was also implemented for fluorescent imaging of tumor-bearing mice to validate its potential application for in vivo imaging of bioanalytes and biomarkers.

Transcriptomics and metabolomics reveal the induction of flavonoid biosynthesis pathway in the interaction of Stylosanthes-Colletotrichum gloeosporioides.

Colletotrichum, a hemibiotrophic fungal pathogen with a broad host range, causes a yield-limiting disease called anthracnose. Stylo (Stylosanthes) is a dominant pasture legume in tropics and subtropics, and anthracnose is one of its most destructive disease. Resistance mechanisms against anthracnose in stylo are poorly understood, thus hindering the development of resistant varieties. We performed time-resolved leaf transcriptomics, metabolomics and in vitro inhibition assay to investigate the defense responses against Colletotrichum gloeosporioides in stylo. Transcriptomics demonstrated that flavonoid biosynthetic genes were significantly induced during the infection. Consistently, metabolomics also showed the increased accumulation of flavonoid compounds. In vitro assays showed that phloretin and naringenin inhibited the mycelial growth, and apigenin, daidzein, quercetin and kaempferol suppressed conidial germination of Colletotrichum strains. Together, our results suggest that stylo plants cope with C. gloeosporioides by up-regulation of genes and compounds in flavonoid biosynthesis pathway, providing potential targets for resistance breeding.