Vendelbolacroix8938

Sensing temperature at the subcellular level is of great importance for the understanding of miscellaneous biological processes. However, the development of sensitive and reliable organic fluorescent nanothermometers remains challenging. In this study, we report the fabrication of a novel organic fluorescent nanothermometer and study its application in temperature sensing. First of all, we synthesize a dual-responsive organic luminogen that can respond to the molecular state of aggregation and environmental polarity. Next, natural saturated fatty acids with sharp melting points as well as reversible and rapid phase transition are employed as the encapsulation matrix to correlate external heat information with the fluorescence properties of the luminogen. To apply the composite materials for biological application, we formulate them into colloidally dispersed nanoparticles by a technique that combines in situ surface polymerization and nanoprecipitation. As anticipated, the resultant zwitterionic nanothermometer exhibits sensitive, reversible, reliable, and multiparametric responses to temperature variation within a narrow range around the physiological temperature (i.e., 37 °C). Taking spectral position, fluorescence intensity, and fluorescence lifetime as the correlation parameters, the maximum relative thermal sensitivities are determined to be 2.15% °C-1, 17.06% °C-1, and 17.72% °C-1, respectively, which are much higher than most fluorescent nanothermometers. Furthermore, we achieve the multimodal temperature sensing of bacterial biofilms using these three complementary fluorescence parameters. Besides, we also fabricate a cationic form of the nanothermometer to facilitate efficient cellular uptake, holding great promise for studying thermal behaviors in biological systems.Exponential molecular amplification such as the polymerase chain reaction is a powerful tool that allows ultrasensitive biodetection. Here, we report a new exponential amplification strategy based on photoredox autocatalysis, where eosin Y, a photocatalyst, amplifies itself by activating a nonfluorescent eosin Y derivative (EYH3-) under green light. The deactivated photocatalyst is stable and rapidly activated under low-intensity light, making the eosin Y amplification suitable for resource-limited settings. Through steady-state kinetic studies and reaction modeling, we found that EYH3- is either oxidized to eosin Y via one-electron oxidation by triplet eosin Y and subsequent 1e-/H+ transfer, or activated by singlet oxygen with the risk of degradation. By reducing the rate of the EYH3- degradation, we successfully improved EYH3--to-eosin Y recovery, achieving efficient autocatalytic eosin Y amplification. Additionally, to demonstrate its flexibility in output signals, we coupled the eosin Y amplification with photoinduced chromogenic polymerization, enabling sensitive visual detection of analytes. Finally, we applied the exponential amplification methods in developing bioassays for detection of biomarkers including SARS-CoV-2 nucleocapsid protein, an antigen used in the diagnosis of COVID-19.Thermodynamic and structural properties of the N-alkanoyl-substituted α-amino acids threonine and serine, differing only by one CH3 group in the head group, are determined and compared. Detailed characterization of the influence of stereochemistry proves that all enantiomers form an oblique monolayer lattice structure whereas the corresponding racemates build orthorhombic lattice structures due to dominating heterochiral interactions, except N-C16-dl-serine-ME as first example of dominating homochiral interactions in a racemic mixture of N-alkanoyl-substituted α-amino acids. EGFR inhibitor In all cases, the liquid expanded-liquid condensed (LE/LC) transition pressure of the racemic mixtures is above that of the corresponding enantiomers. Phase diagrams are proposed. Using the program Hardpack to predict tilt angles and cross-sectional area of the alkyl chains shows reasonable agreement with the experimental grazing incidence X-ray diffraction (GIXD) data.Silverweed cinquefoil roots, as dietary supplements, foods, and medicines, are widely used in western areas of China, specifically in Tibet Autonomous Region and Gansu and Qinghai Provinces. In this paper, 10 new natural pentacyclic triterpenoid saponins (1-10), named poterinasides A-J, along with 14 known compounds (11-24) were isolated and purified from silverweed cinquefoil roots. The chemical structures of 1-10 were established by extensive analysis of 1D and 2D NMR data and mass spectrometric data. Poterinasides A (1), B (2), and G (7) with the unique position of substituents on the E ring had never been discovered in natural products before. Saponins 1-8, 14, and 22 displayed potent hepatoprotective activities, and 1-8, 10, 11, 14, 16, 19, and 22-24 showed outstanding anti-inflammatory effects. On the basis of the present results, some structure-activity relationships were summarized, in which 3α-OH, 19β-CH3, 20α-CH3, 20β-CH3, 21α-OH, and 30-OH groups in isolated pentacyclic triterpenoid saponins were found to strengthen the hepatoprotective and anti-inflammatory activities, respectively. Further, the following pharmacophore-based virtual screening and docking studies on special targets proteins, SIRT1 and COX-2, revealed roughly similar results with the structure-activity relationships, and this combination method was used for the first time for active natural compound screening.Designer C-terminal peptide amides are accessed in an efficient and epimerization-free approach by pairing an electrochemical oxidative decarboxylation with a tandem hydrolysis/reduction pathway. Resembling Nature's dual enzymatic approach to bioactive primary α-amides, this method delivers secondary and tertiary amides bearing high-value functional motifs, including isotope labels and handles for bioconjugation. The protocol leverages the inherent reactivity of C-terminal carboxylates, is compatible with the vast majority of proteinogenic functional groups, and proceeds in the absence of epimerization, thus addressing major limitations associated with conventional coupling-based approaches. The utility of the method is exemplified through the synthesis of natural product acidiphilamide A via a key diastereoselective reduction, as well as bioactive peptides and associated analogues, including an anti-HIV lead peptide and blockbuster cancer therapeutic leuprolide.