Loureirin B activates GLP-1R and promotes insulin secretion in Ins-1 cells.

Loureirin B (LB) is a natural product derived from Sanguis draconis, which has hypoglycaemic effects. In order to research the possible target of LB in the treatment of diabetes, molecular docking was used to simulate the interaction between LB and potential targets, and among them, glucagon-like peptide-1 receptor (GLP-1R) had the optimal results. Further, spectroscopy and surface plasmon resonance (SPR) experiments were applied to detect the interaction between LB and GLP-1R. Ultimately, after GLP-1R siRNA interfering the expression of GLP-1R in Ins-1 cell, the promoting insulin secretion of LB was weaken, which directly proved that GLP-1R plays an important role. These results show that LB promotes insulin secretion of Ins-1 cells through GLP-1R. Hence, the strategy of LB as a prodrug will provide a potential approach for non-peptide GLP-1R agonist.

From Monochrome to Technicolor: Simple Generic Approaches to Multicomponent Protein Nanopatterning Using Siloxanes with Photoremovable Protein-Resistant Protecting Groups.

We show that sequential protein deposition is possible by photodeprotection of films formed from a tetraethylene-glycol functionalized nitrophenylethoxycarbonyl-protected aminopropyltriethoxysilane (NPEOC-APTES). Exposure to near-UV irradiation removes the protein-resistant protecting group, and allows protein adsorption onto the resulting aminated surface. The protein resistance was tested using proteins with fluorescent labels and microspectroscopy of two-component structures formed by micro- and nanopatterning and deposition of yellow and green fluorescent proteins (YFP/GFP). Nonspecific adsorption onto regions where the protecting group remained intact was negligible. Multiple component patterns were also formed by near-field methods. Because reading and writing can be decoupled in a near-field microscope, it is possible to carry out sequential patterning steps at a single location involving different proteins. Up to four different proteins were formed into geometric patterns using near-field lithography. Interferometric lithography facilitates the organization of proteins over square cm areas. Two-component patterns consisting of 150 nm streptavidin dots formed within an orthogonal grid of bars of GFP at a period of ca. 500 nm could just be resolved by fluorescence microscopy.

Fabrication of Nanometer- and Micrometer-Scale Protein Structures by Site-Specific Immobilization of Histidine-Tagged Proteins to Aminosiloxane Films with Photoremovable Protein-Resistant Protecting Groups.

The site-specific immobilization of histidine-tagged proteins to patterns formed by far-field and near-field exposure of films of aminosilanes with protein-resistant photolabile protecting groups is demonstrated. After deprotection of the aminosilane, either through a mask or using a scanning near-field optical microscope, the amine terminal groups are derivatized first with glutaraldehyde and then with N-(5-amino-1-carboxypentyl)iminodiacetic acid to yield a nitrilo-triacetic-acid-terminated surface. After complexation with Ni(2+), this surface binds histidine-tagged GFP and CpcA-PEB in a site-specific fashion. The chemistry is simple and reliable and leads to extensive surface functionalization. Bright fluorescence is observed in fluorescence microscopy images of micrometer- and nanometer-scale patterns. X-ray photoelectron spectroscopy is used to study quantitatively the efficiency of photodeprotection and the reactivity of the modified surfaces. The efficiency of the protein binding process is investigated quantitatively by ellipsometry and by fluorescence microscopy. We find that regions of the surface not exposed to UV light bind negligible amounts of His-tagged proteins, indicating that the oligo(ethylene glycol) adduct on the nitrophenyl protecting group confers excellent protein resistance; in contrast, exposed regions bind His-GFP very effectively, yielding strong fluorescence that is almost completely removed on treatment of the surface with imidazole, confirming a degree of site-specific binding in excess of 90%. This simple strategy offers a versatile generic route to the spatially selective site-specific immobilization of proteins at surfaces.

Zwitterionic poly(amino acid methacrylate) brushes.

A new cysteine-based methacrylic monomer (CysMA) was conveniently synthesized via selective thia-Michael addition of a commercially available methacrylate-acrylate precursor in aqueous solution without recourse to protecting group chemistry. Poly(cysteine methacrylate) (PCysMA) brushes were grown from the surface of silicon wafers by atom-transfer radical polymerization. Brush thicknesses of ca. 27 nm were achieved within 270 min at 20 °C. Each CysMA residue comprises a primary amine and a carboxylic acid. Surface zeta potential and atomic force microscopy (AFM) studies of the pH-responsive PCysMA brushes confirm that they are highly extended either below pH 2 or above pH 9.5, since they possess either cationic or anionic character, respectively. At intermediate pH, PCysMA brushes are zwitterionic. At physiological pH, they exhibit excellent resistance to biofouling and negligible cytotoxicity. PCysMA brushes undergo photodegradation: AFM topographical imaging indicates significant mass loss from the brush layer, while XPS studies confirm that exposure to UV radiation produces surface aldehyde sites that can be subsequently derivatized with amines. UV exposure using a photomask yielded sharp, well-defined micropatterned PCysMA brushes functionalized with aldehyde groups that enable conjugation to green fluorescent protein (GFP). Nanopatterned PCysMA brushes were obtained using interference lithography, and confocal microscopy again confirmed the selective conjugation of GFP. Finally, PCysMA undergoes complex base-catalyzed degradation in alkaline solution, leading to the elimination of several small molecules. However, good long-term chemical stability was observed when PCysMA brushes were immersed in aqueous solution at physiological pH.

Au@SiO2 core-shell nanoparticles for laser desorption/ionization time of flight mass spectrometry.

In matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), the analysis capability, especially for small molecules, is often compromised by the addition of organic matrices due to the existence of background signals. Herein we report a new detection method on the utility of core-shell nanoparticles (CSNPs) as energy transfer structure in LDI-TOF-MS. The LDI-TOF-MS based on gold-silica core-shell nanoparticles with ultrathin silica shell of 2-4 nm (Au@utSiO(2) CSNPs) was effectively applied to the analysis of many compounds, especially for small functional molecules and polymers, which was more promising than MALDI-TOF-MS.

Loureirin B promotes insulin secretion through GLP-1R and AKT/PDX1 pathways.

Loureirin B (LB), a natural product derived from Sanguis draconis, has hypoglycemic effects in diabetic mice. However, there are no studies on how LB lowers blood glucose. In this study, we first treated a diabetic model in mice with LB, and the results showed that LB lowered blood glucose and alleviated islet damage in mice. Next, Ins-1 cells were treated with LB. The results showed that LB could promote cell proliferation and reduce apoptosis of Ins-1 cells. Loureirin B (LB), a natural product derived from Sanguis draconis, has hypoglycemic effects in diabetic mice. However, there are no studies on how LB lowers blood glucose. In this study, we first treated mice with LB in a diabetic model and showed that LB lowered blood glucose and reduced islet damage in mice. Next, Ins-1 cells were treated with LB. The results showed that LB could promote cell proliferation and reduce apoptosis of Ins-1 cells. Further, after inhibiting GLP-1R activity, the results showed that LB promoted insulin secretion, Ins-1 cell proliferation and reduced Ins-1 cell apoptosis with reduced effect, indicating that LB achieved the above effects by activating GLP-1Ra. Meanwhile, cellular cAMP levels increased when GLP-1R was overexpressed, which also demonstrated the interaction between LB and GLP-1R. Subsequently, the effect of LB on cellular potassium channels was examined by membrane clamp, and the results showed that LB increased intracellular Ca2+ concentration and stimulated insulin secretion by activating GLP-1R and thus closing the ATP-sensitive potassium channels. On the other hand, the activation effect of LB on AKT/PDX1 signaling pathway was verified.

Metal ion detection with oligo(ethylene glycol) monolayer-modified gold nanoparticles.

Two colorimetric sensors of gold nanoparticles (AuNPs) modified with different oligo(ethylene glycol)-containing organic molecules have been developed to detect metal ions by ultraviolet-visible (UV-vis) extinction spectroscopy. These sensors display different responses to some metal ions. One exhibits high selectivity for Hg2+ over a variety of competitive metal ions and the other one can respond to a multitude of metal ions. These differences might result from the different functionalized end groups of the modified molecules. Coordination effect, pH response, and ionic strength were investigated to understand the mechanism of the responses to metal ions. The results suggested that the colorimetric responses were mainly induced by the coordination effect of the modified organic molecules and the removing of the modified organic molecules caused by metal ions.

Risk Analysis of Veterinary Drug Residues in Aquatic Products in the Yangtze River Delta of China.

ABSTRACT: Aquatic products are favored by people all over the world, but the potential quality and safety issues cannot be ignored. To determine the risk of veterinary drug residues in aquatic products in the Yangtze River Delta, this study used geographic information system method to analyze Chinese veterinary drugs in aquatic products in Shanghai, Jiangsu, Zhejiang, and Anhui (Yangtze River Delta Urban Agglomerations) from 2017 to 2019. A study of the spatial distribution pattern, hot spot detection and analysis, and spatiotemporal cluster analysis of the residual excess rate and detection rate showed a random spatial distribution in the overall excess rate and detection rate of veterinary drug residues in aquatic products from 2017 to 2019. The results of hot spot analysis and spatiotemporal cluster analysis showed that the rate of detection of veterinary drug residues and the rate of detection of residues in excess of regulatory standards were clustered. This study provides a scientific basis for food safety evaluation and risk management suggestions.

Loureirin B attenuates insulin resistance in HepG2 cells by regulating gluconeogenesis signaling pathway.

Insulin resistance (IR) is the main cause of type 2 diabetes. The liver is the organ where insulin is secreted from the pancreas, and it regulates the storage and release of glucose according to the body's demand. Althouth Loureirin B (LB) has been reported to promote insulin secretion and decrease blood glucose, the effects of LB on glucose metabolism in the liver and the mechanism is still unclear. Different concentrations of LB were applied to treat on insulin resistance model (IR-HepG2) cells. The research results showed that LB inhibited the production of ROS (Reactive oxygen species) in IR-HepG2 cells, promoted the phosphorylation of AKT, down-regulated the expression of FoxO1, and up-regulated the expression of IRS1 and GLUT4. In addition, LB also down regulated the glucose metabolism related genes PEPCK and GSK3ß. The glucose uptake, consumption and glycogen content were increased. Moreover, LB-treated diabetic mice also showed hypoglycaemic effects. In summary, LB may ameliorate type 2 diabetes by preventing the inactivation of IRS1/AKT pathway in IR-HepG2 cells, increasing insulin sensitivity, and regulating glucose uptake and production.

Biomineralization-assisted ultrasensitive detection of DNA.

The development of instrument-free, PCR-less, ultrasensitive and selective DNA detection methods is highly desired in chemical and life sciences. Herein we report on the utility of a biomineralization-assisted amplification methodology for the identification of DNA. Significantly, the diagnostic strategy has allowed the target detection at a concentration as low as 50 aM, equivalent to approximately 180 copies in the entire 6 microL sample. In addition, the DNA sequence with a single-base mismatch can be differentiated from the perfect target through a facile salt-based stringency wash. Substitution of the DNA structures with other recognition moieties should allow the translation of the strategy to the assay of different targets of interest. The visual readout format provides a sound basis for the broad applicability of the proposed strategy, especially in resource-poor settings.

CD28: A New Drug Target for Immune Disease.

BACKGROUND: CD28, a cell surface glycoprotein receptor, predominantly expressed on activated T cells, belongs to the Ig superfamily and provides a critical co-stimulatory signal. CTLA-4 has sequence homology to CD28, and is expressed on T cells after activation. It provides an inhibition signal coordinated with CD28 to regulate T cell activation. Both of them regulate T cell proliferation and differentiation and play an important role in the immune response pathway in vivo. OBJECTIVE: We studied the special role of different structural sites of CD28 in producing costimulatory signals. METHODS: We reviewed the relevant literature, mainly regarding the structure of CD28 to clarify its biological function, and its role in the immune response. RESULTS: In recent years, increasingly attention has been paid to CD28, which is considered as a key therapeutic target for many modern diseases, especially some immune diseases. CONCLUSION: In this paper, we mainly introduce the structure of CD28 and its related biological functions, as well as the application of costimulatory pathways targeting CD28 in disease treatment.

Dairy Safety Prediction Based on Machine Learning Combined with Chemicals.

BACKGROUND: Dairy safety has caused widespread concern in society. Unsafe dairy products have threatened people's health and lives. In order to improve the safety of dairy products and effectively prevent the occurrence of dairy insecurity, countries have established different prevention and control measures and safety warnings. OBJECTIVE: The purpose of this study is to establish a dairy safety prediction model based on machine learning to determine whether the dairy products are qualified. METHODS: The 34 common items in the dairy sampling inspection were used as features in this study. Feature selection was performed on the data to obtain a better subset of features, and different algorithms were applied to construct the classification model. RESULTS: The results show that the prediction model constructed by using a subset of features including "total plate", "water" and "nitrate" is superior. The SN, SP and ACC of the model were 62.50%, 91.67% and 72.22%, respectively. It was found that the accuracy of the model established by the integrated algorithm is higher than that by the non-integrated algorithm. CONCLUSION: This study provides a new method for assessing dairy safety. It helps to improve the quality of dairy products, ensure the safety of dairy products, and reduce the risk of dairy safety.

Prediction for global African swine fever outbreaks based on a combination of random forest algorithms and meteorological data.

African swine fever (ASF) is a virulent infectious disease of pigs. As there is no effective vaccine and treatment method at present, it poses a great threat to the pig industry once it breaks out. In this paper, we used ASF outbreak data and the WorldClim database meteorological data and selected the CfsSubset Evaluator-Best First feature selection method combined with the random forest algorithms to construct an African swine fever outbreak prediction model. Subsequently, we also established a test set for data other than modelling, and the accuracy accuracy value range of the model on the independent test set was 76.02%-84.64%, which indicated that the modelling effect was better and the prediction accuracy was higher than previous estimates. In addition, logistic regression analysis was conducted on 12 features used for modelling and the ROC curves were drawn. The results showed that the bio14 features (precipitation of driest month) had the largest contribution to the outbreak of ASF, and it was speculated that the outbreak of the epidemic was significantly related to precipitation. Finally, we used this qualitative prediction model to build a global online prediction system for ASF outbreaks, in the hope that this study will help to decision-makers who can then take the relevant prevention and control measures in order to prevent the further spread of future epidemics of the disease.

Versatile thiol-based reactions for micrometer- and nanometer-scale photopatterning of polymers and biomolecules.

Thiol-based chemistry provides a mild and versatile tool for surface functionalization. In the present work, mercaptosilane films were patterned by utilizing UV-induced photo-oxidation of the thiol to yield sulfonate groups via contact and interferometric lithography (IL). These photo-generated sulfonic acid groups were used for selective immobilization of amino-functionalized molecules after activation with triphenylphosphine ditriflate (TPPDF). Moreover, protein-resistant poly(oligoethyleneglycolmethacrylate) (POEGMA) brushes were grown from the intact thiol groups by a surface-induced polymerization reaction. Exploiting both reactions it is possible to couple amino-labelled nitrilotriacetic acid (NH2-NTA) to sulfonate-functionalized regions, enabling the site-specific binding of green fluorescent protein (GFP) to regions defined lithographically, while exploiting the protein-resistant character of POEGMA brushes to prevent non-specific protein adsorption to previously masked areas. The outstanding reactivity of thiol groups paves the way towards novel strategies for the fabrication of complex protein nanopatterns beyond thiol-ene chemistry.

Diversified nanoparticle assembly pathways: materials architecture control beyond the amphiphilicity paradigm.

The functional versatility of a chemical system is ultimately dictated by the availability of distinctly accessible architectures. The generation of a diverse array of assembled constructs from a single type of nanoscale building block is a promising yet largely elusive goal. We report herein the utility of a monolayer-modified nanoparticle for the creation of a broad range of architectures. The versatile modes of assembly complement the conventionally used, amphiphilicity-driven strategy. We demonstrate that one can vary the nanoparticle assembly pathways within the confines of solvent media through the modulation of interactions and partitioning of nanoparticles. Merging of the molecular-scale design and higher-ordered arrangement enables diversified assembly through the manipulation of experimental parameters such as solvent, pH, affinity molecule, and temperature. Microfluidics provides an effective channel to control the monodispersity and size on all the architectures attainable in the bulk solution phase. These observations could be further explored for an understanding of diversified matter organization and order generation beyond the amphiphilicity paradigm.