Molecular spectroscopy and docking simulation revealed the binding mechanism of phenol onto anammox sludge extracellular polymeric substances

The rapid development of chemical industry has induced to the large amount of phenolic wastewater production. When the promising anaerobic ammonium oxidation (anammox) was employed to treat the industrial wastewater, phenolic compounds would possibly inhibit the microbial performance. Extracellular polymeric substances (EPSs) play an essential role in protecting cells from being intoxicated by phenolic compound while the distinct mechanism remains elusive. In this work, the interaction of phenol with anammox sludge EPSs and transmembrane ammonium transport (Amt) domain was explored at molecular level by using spectral method and molecular docking simulation. It was found that phenol statically quenched the fluorescent components of EPSs and the protein component dominated the interaction between EPSs and phenol. The overall interaction was an entropy-driven process with hydrophobic interaction as the main driving force, and the CO vibration responded preferentially. As phenol continued to penetrate into the cell surface, there were hydrogen bond, hydrophobic interaction force and π-π base-stacking forces between the Amt domain and phenol. The interaction between phenol and amino acid residues of the Amt domain would interfere the NH₄⁺ transport and further affect the activity of anammox sludge. This work is beneficial for in-depth understanding the role of EPSs in protecting anammox sludge from inhibiting by phenolic pollutants.

Development and Therapeutic Potential of Selenazo Compounds

Incorporation of selenium (Se) atom into small molecules can substantially enhance their antioxidant, anti-inflammatory, antimutagenic, antitumoral or chemopreventive, antiviral, antibacterial, antifungal, antiparasitic, and neuroprotective effects. Specifically, selenazo compounds have received great attention owing to their chemical properties, pharmaceutical applications, and low toxicity. In this Perspective, we compile extensive literature evidence with the description and discussion of the most recent advances in different selenazo and selenadiazo motifs as potential pharmacological candidates. We also provide some perspectives on the challenges and future directions in the advancement of these selenazo compounds, each of which could generate drug candidates for various diseases.

Imaging of Hypochlorous Acid by Fluorescence and Applications in Biological Systems

In recent decades, HOCl research has attracted a lot of scientists from around the world. This chemical species is well known as an important player in the biological systems of eukaryotic organisms including humans. In the human body, HOCl is produced by the myeloperoxidase enzyme from superoxide in very low concentrations (20 to 400 μm); this species is secreted by neutrophils and monocytes to help fight pathogens. However, in the condition called "oxidative stress", HOCl has the capability to attack many important biomolecules such as amino acids, proteins, nucleotides, nucleic acids, carbohydrates, and lipids; these reactions could ultimately contribute to a number of diseases such as neurodegenerative diseases (AD, PD, and ALS), cardiovascular diseases, and diabetes. In this review, we discuss recent efforts by scientists to synthesize various fluorophores which are attached to receptors to detect HOCl such as: chalcogen-based oxidation, oxidation of 4-methoxyphenol, oxime/imine, lactone ring opening, and hydrazine. These synthetic molecules, involving rational synthetic pathways, allow us to chemoselectively target HOCl and to study the level of HOCl selectivity through emission responses. Virtually all the reports here deal with well-defined and small synthetic molecular systems. A large number of published compounds have been reported over the past years; this growing field has given scientists new insights regarding the design of the chemosensors. Reversibility, for example is considered important from the stand point of chemosensor reuse within the biological system; facile regenerability using secondary analytes to obtain the initial probe is a very promising avenue. Another aspect which is also important is the energy of the emission wavelength of the sensor; near-infrared (NIR) emission is favorable to prevent autofluorescence and harmful irradiation of tissue; thus, extended applicability of such sensors can be made to the mouse model or animal model to help image internal organs. In this review, we describe several well-known types of receptors that are covalently attached to the fluorophore to detect HOCl. We also discuss the common fluorophores which are used by chemist to detect HOCl, Apart from the chemical aspects, we also discuss the capabilities of the compounds to detect HOCl in living cells as measured through confocal imaging. The growing insight from HOCl probing suggests that there is still much room for improvement regarding the available molecular designs, knowledge of interplay between analytes, biological applicability, biological targeting, and chemical switching, which can also serve to further sensor and theurapeutic agent development alike.

Potentiation of in Vivo Anticancer Efficacy of Selenium Nanoparticles by Mushroom Polysaccharides Surface Decoration

Selenium nanoparticles (SeNPs) are recently emerging as promising anticancer agents because of their high bioavailability, low toxicity and remarkable anticancer activities. However, the effects of surface physicochemical properties on the biological actions remain elusive. Herein we decorated SeNPs with various water-soluble polysaccharides extracted from various mushrooms, to compare physical characteristics and anticancer profile of these SeNPs. The results showed that the prepared spherical SeNPs displayed particle sizes at 91-102 nm, and kept stable in aqueous solution for up to 13 weeks. However, different decoration altered the tumor selectivity of the SeNPs, while gastric adenocarcinoma AGS cells showed relative highest sensitivity. Moreover, PTR-SeNPs demonstrated potent in vivo antitumor, by inducing caspases- and mitochondria-mediated apoptosis, but showed no obvious toxicity to nomal organs. Taken together, this study offers insights into how surface decoration can tune the cancer selectivity of SeNPs and provides a basis for engineering particles with increased anticancer efficacy.

Synthesis and antiproliferative activity of 17-[1',2',3']-selenadiazolylpregnenolone compounds

Using pregnenolone as a starting material, some 3-substituted 17-[1',2',3']-selenadiazolylpregnenolone derivatives were synthesized, and their structures were characterized by IR, NMR and HRMS. The in vitro antitumor activity of the compounds was assayed against PC-3、SKOV3、T47D、MCF-7 and HEK293T cell lines. The results show that some compounds display selective antiproliferative activity against PC-3 and SKOV3 cells lines and are almost inactive to normal kidney epithelial cells (HEK293T). The IC₅₀ value are much better than that of abiraterone (positive control).

Potent anti-proliferative activities of organochalcogenocyanates towards breast cancer

The synthesis of benzylic and mesitylenic organochalcogenocyanates has been described and the compounds have been studied for their anti-proliferative activities in breast cancer cells (MDA-MB-231, MCF-7 and T-47D).

Albumin-templated biomineralizing growth of composite nanoparticles as smart nano-theranostics for enhanced radiotherapy of tumors

Hypoxia and a dense extracellular matrix within the tumor microenvironment can often lead to the resistance of tumors to radiotherapy. Herein, we use bovine serum albumin (BSA) as a template to induce the growth of both gold (Au) nanoclusters and manganese dioxide (MnO₂) via biomineralization. In the obtained BSA-Au-MnO₂ composite nanoparticles, Au nanoclusters embedded within BSA not only show strong red fluorescence to facilitate imaging, but also act as a radio-sensitizer by absorbing and depositing X-ray energy within tumors to enhance radiotherapy. Meanwhile, the MnO₂ core, which enables the formation of composite nanoparticles by connecting multiple albumins together, is able to modulate the tumor hypoxia by triggering the decomposition of tumor endogenous H₂O₂ into oxygen, so as to reverse the hypoxia-associated radiation resistance of tumors. Notably, such BSA-Au-MnO₂ composite nanoparticles with larger sizes show prolonged blood circulation and increased tumor accumulation compared to BSA-Au complexes, and would dissociate back into individual BSA-Au complexes once inside the tumor with reduced pH to allow deep interstitial diffusion. As a result, highly effective radiotherapy of tumors is realized with these nanoparticles in a mouse tumor model. Our work thus presents a convenient biomineralization approach to fabricate intelligent multifunctional nanoparticles composed of biocompatible/biodegradable components for enhanced cancer therapy.