Discovery of (E)-3-(4-(Diethylamino) phenyl)-1-phenyl-2-phenylsulfonyl)prop-2-en-1-one as Novel Cannabinoid Receptor 2 Ligands

Cannabinoids (CB) are defined as a class of compounds that can act on Cannabinoid receptors 1 or 2 (CB1 or CB2) and affect human physiology. Both CB1 and CB2 receptors belong to the rhodopsin-like family of G-Protein Coupled Receptors (GPCRs). However, CB1 receptor is mainly expressed in the central nervous system, while CB2 receptor is dominantly located in the peripheral nervous system and immune cells. By now, scientists have discovered many CB ligands that have therapeutic potentials, but the limitation of non-selective ligands is the psychiatric side effect mediated by the activation of CB1 receptor. Although CB1 receptor is crucial in analgesic and anti-inflammatory effects, strategies of designing CB2 selective ligands are made by medicinal chemists to avoid undesirable effects in clinic. In this thesis, we discovered novel CB2 lead compounds with new chemical scaffolds; designed and synthesized four series of analogues for the structure-activity relationship (SAR) studies; tested their binding affinity to both CB2 and CB1 receptors; conducted in-vitro functional studies; and evaluated their potentials for therapeutic treatment. In total, four series of (E)-3-(4-Ethoxy-3-methoxyphenyl)-2-((4-methoxyphenyl) sulfonyl)-1-phenylprop-2-en-1-one have been identified as novel cannabinoid ligands. Physicochemical properties were predicted and docking studies using our CB2 model was conducted. 29 derivatives were then synthesized to conduct SAR studies. The binding affinity and selectivity for cannabinoid receptor CB1 and CB2 were then evaluated. Four compounds showed high CB2 binding affinity (Ki of 10-60 nM) and good selectivity (CB1/CB2 of 20- to 1305 fold). Their off-targets effects were also predicted. Overall, these sulfone derivatives can be used to develop novel therapeutic CB2 ligands

Structure Elucidation, Signaling Mechanism and Structure-Based Lead Design of the Human Cannabinoid Receptor 2 (CB2)

Cannabinoid receptor 2 (CB2) has an important role in mediating immune signal transduction and is an attractive therapeutic target for chronic neuropain, osteoporosis, autoimmune diseases, and tumors of immune origin. Unlike CB1, which is expressed in the central nervous system (CNS), CB2 is primarily expressed in cells of the immune system and its selective modulation will not produce psychoactive effects. This feature has attracted great interest in CB2, particularly since the anti-obesity drug Rimonabant (CB1 antagonist) was withdrawn from the European market due to depression side effects. Despite research efforts to date, the CB2 active-state structure, activation mechanism, and allosteric binding features remain elusive, representing a significant hindrance in the development of novel CB2 agonist and allosteric modulators. Thus, in this study, we first unveiled the cryo-EM structure of CB2-Gi signaling complex to gain an unprecedented understanding of the structural and functional mechanisms inherent to CB2 using high-end biophysical and biochemical approaches with purified functional CB2. Next, we developed and applied an innovative residual energy calculation algorithm to aid in the design of a pair of selective CB2 agonist and inverse agonist in order to validate our putative mechanism of receptor activation involving the structural arrangement of critical residues. Then, we investigated the binding features of selective CB2 agonists, as well as the CB2 biased ligand and CB2 positive allosteric modulators (PAMs) and negative allosteric modulators (NAMs). Collectively, the results from this study will provide insightful information to facilitate structure-based design and discovery of high-affinity and/or high-selectivity CB2 ligands that can be developed as CB2-targeting therapeutic agents

Fate of Fe3O4@NH2 in soil and their fixation effect to reduce lead translocation in two rice cultivars

Abstract The fate of nanoparticles in the ecological chain of agriculture has been concerned as their potential pollution and biological effect to humans with rapid development and massive emission of nanomaterials. Here, we found that two rice cultivars (Oryza sativa L) have different heavy metal accumulation results in the roots and shoots after 15 days growth. Two rice cultivars (Oryza sativa L), grown in soil containing magnetite (Fe3O4@NH2) nanoparticles and heavy metal simultaneous, showed less Pb uptake in the roots and shoots, compared with that without Fe3O4@NH2 added. The shape and magnetic properties of Fe3O4@NH2 have no obvious change; however, the transmission electron microscope (TEM) results showed the shell of Fe3O4@NH2 could be broken in the process of interaction with soil. These results suggested that magnetite nanoparticles, such as Fe3O4@NH2, could potentially be used as the recyclable heavy metal fixation materials for alleviating heavy metal poisoning to plant

A Sensitive DNAzyme-Based Chiral Sensor for Lead Detection

A DNAzyme-based sensor for the determination and quantification of lead ions (Pb2+) has been established, which combines the recognition and catalysis of DNAzyme with the optical properties of nanomaterials. Circular dichroism (CD) signals were obtained by a DNAzyme-based assembly of asymmetric silver nanoparticle (AgNPs) dimers. A good linear relationship between CD signals and Pb2+ concentration was obtained ranging from 0.05 ng∙mL−1 to 10 ng∙mL−1 with a limit of detection (LOD) of 0.02 ng∙mL−1. The specificity of this sensor in lead ion detection was excellent, and a satisfactory recovery was obtained in the analysis of tap water samples. The proposed technique possesses both high sensitivity and good specificity, giving it great potential for the analysis of Pb2+ in water

Bioaugmentation with a propionate-degrading methanogenic culture to improve methane production from chicken manure

Volatile fatty acid (VFA) accumulation caused by high ammonia concentrations is often encountered during the anaerobic digestion (AD) of ammonia-rich substrates. In this study, propionate-degrading methanogenic cultures were introduced to augment the semi-continuous AD of chicken manure under high ammonia levels. Introduction of a methanogenic culture enhanced the methane yield in the bioaugmented digester by 17-26% when the organic loading rate (OLR) was 2-4 g L(-1)d(-1) compared to that in the control. When the OLR was further increased from 4.0 L(-1)d(-1) to 5.0 g L(-1)d(-1), and bioaugmentation ceased, methane yield improved by 15-18% under a high total ammonia nitrogen level of 5.0-8.4 g NH4+-N/L. Moreover, bioaugmentation reconstructed the methanogenic community in the digester, promoting the dominance of hydrogenotrophic Methanobacterium and slightly increasing the abundance of aceticlastic Methanothrix and the syntrophic propionate-oxidizing bacteria Syntrophobacter, which were the key contributors to the improved AD under high ammonia concentrations

Development of an ELISA and Immunochromatographic Strip for Highly Sensitive Detection of Microcystin-LR

A monoclonal antibody for microcystin–leucine–arginine (MC-LR) was produced by cell fusion. The immunogen was synthesized in two steps. First, ovalbumin/ bovine serum albumin was conjugated with 6-acetylthiohexanoic acid using a carbodiimide EDC (1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride)/ NHS (N-hydroxysulfosuccinimide) reaction. After dialysis, the protein was reacted with MC-LR based on a free radical reaction under basic solution conditions. The protein conjugate was used for immunization based on low volume. The antibodies were identified by indirect competitive (ic)ELISA and were subjected to tap water and lake water analysis. The concentration causing 50% inhibition of binding of MC-LR (IC50) by the competitive indirect ELISA was 0.27 ng/mL. Cross-reactivity to the MC-RR, MC-YR and MC-WR was good. The tap water and lake water matrices had no effect on the detection limit. The analytical recovery of MC-LR in the water samples in the icELISA was 94%–110%. Based on this antibody, an immunochromatographic biosensor was developed with a cut-off value of 1 ng/mL, which could satisfy the requirement of the World Health Organization for MC-LR detection in drinking water. This biosensor could be therefore be used as a fast screening tool in the field detection of MC-LR

Determination of soybean routine quality parameters using near‐infrared spectroscopy

Large differences in quality existed between soybean samples. In order to rapidly detect soybean quality between samples from different areas, we have developed near‐infrared spectroscopy (NIRS) models for the moisture, crude fat, and protein content of soybeans, based on 360 soybean samples collected from different areas. Compared with whole kernels, soybean powder with particle sizes of 60 mesh was more suitable for modeling of moisture, crude fat, and protein content. To increase the reproducibility of the prediction model, uniform particle sizes of soybeans were prepared by grinding and sieving soybeans with different sizes and colors. Modeling analysis showed that the internal cross‐validation correlation coefficients (Rcv) for the moisture, crude fat, and protein content of soybeans were .965, .941, and .949, respectively, and the determination coefficients (R2) were .966, .958, and .958. NIRS performed well as a rapid method for the determination of routine quality parameters and provided reference data for the analysis of soybean quality using FT‐NIRS

Development and optimization of an immunoassay for the detection of Hg(II) in lake water

Abstract In this paper, an indirect competitive enzyme‐linked immunosorbent assay (IC‐ELISA) has been developed and optimized to detect Hg(II) in tap water and lake water based on a monoclonal antibody (mAb‐A24). Some stabilizing additives (Gelatin, bovine serum albumin [BSA], polyvinyl alcohol [PVA], and polyvinyl pyrrolidone [PVP]) and surfactant (Tween‐20) have been investigated thoroughly in the optimization process. Under the optimal condition, the 50% half maximal inhibitory concentration (IC50) and limit of detection (LOD) were 1.68 and 0.079 ng/ml, respectively. These anti‐Hg mAbs also have some affinity with methyl mercury (CH3Hg) and with no cross‐reactivity with other thirteen metal ions. The developed method has shown satisfactory recovery of Hg(II), ranged between 91% and 116%, from tap water and lake water. Therefore, this immunoassay can be used to detect trace Hg(II) in environment water