Phosphorylation and Methylation of Proteasomal Proteins of the Haloarcheon Haloferax volcanii

Proteasomes are composed of 20S core particles (CPs) of α- and β-type subunits that associate with regulatory particle AAA ATPases such as the proteasome-activating nucleotidase (PAN) complexes of archaea. In this study, the roles and additional sites of post-translational modification of proteasomes were investigated using the archaeon Haloferax volcanii as a model. Indicative of phosphorylation, phosphatase-sensitive isoforms of α1 and α2 were detected by 2-DE immunoblot. To map these and other potential sites of post-translational modification, proteasomes were purified and analyzed by tandem mass spectrometry (MS/MS). Using this approach, several phosphosites were mapped including α1 Thr147, α2 Thr13/Ser14 and PAN-A Ser340. Multiple methylation sites were also mapped to α1, thus, revealing a new type of proteasomal modification. Probing the biological role of α1 and PAN-A phosphorylation by site-directed mutagenesis revealed dominant negative phenotypes for cell viability and/or pigmentation for α1 variants including Thr147Ala, Thr158Ala and Ser58Ala. An H. volcanii Rio1p Ser/Thr kinase homolog was purified and shown to catalyze autophosphorylation and phosphotransfer to α1. The α1 variants in Thr and Ser residues that displayed dominant negative phenotypes were significantly reduced in their ability to accept phosphoryl groups from Rio1p, thus, providing an important link between cell physiology and proteasomal phosphorylation

Synthesis and Characterization of Pyrochlore Bi 2

Praseodymium doped Bi2Sn2O7 (BSO), as a visible-light responsive photocatalyst, was prepared by a hydrothermal method with different dopant contents. The as-prepared photocatalysts were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), N2 adsorption-desorption isotherm, X-ray photoelectron spectroscopy analysis (XPS), and UV-Vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of prepared catalysts was evaluated by the degradation of Rhodamine Bextra (RhB) and 2,4-dichlorophenol (2,4-DCP) in aqueous solution under visible light irradiation. It was found that Pr doping inhibited the growth of crystalline size and the as-prepared materials were small in size (10–20 nm). In our experiments, Pr-doped BSO samples exhibited enhanced visible-light photocatalytic activity compared to the undoped BSO, and the optimal dopant amount of Pr was 1.0 mol% for the best photocatalytic activity. On the basis of the calculated PL spectra, the mechanism of enhanced photocatalytic activity has been discussed

The Immunologic Injury Composite with Balloon Injury Leads to Dyslipidemia: A Robust Rabbit Model of Human Atherosclerosis and Vulnerable Plaque

Atherosclerosis is a condition in which a lipid deposition, thrombus formation, immune cell infiltration, and a chronic inflammatory response, but its systemic study has been hampered by the lack of suitable animal models, especially in herbalism fields. We have tried to perform a perfect animal model that completely replicates the stages of human atherosclerosis. This is the first combined study about the immunologic injury and balloon injury based on the cholesterol diet. In this study, we developed a modified protocol of the white rabbit model that could represent a novel approach to studying human atherosclerosis and vulnerable plaque

CTAB-Assisted Hydrothermal Synthesis of Bi 2

Pyrochlore-type Bi2Sn2O7 (BSO) nanoparticles have been prepared by a hydrothermal method assisted with a cationic surfactant cetyltrimethylammonium bromide (CTAB). These BSO products were characterized by powder X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and UV-visible diffuse reflectance spectroscopy (DRS). The results indicated that CTAB alters the surface parameters and the morphology and enhances the photoinduced charge separation rate of BSO. The photocatalytic degradation test using rhodamine B as a model pollutant showed that the photocatalytic activity of the BSO assisted with CTAB was two times that of the reference BSO. Close investigation revealed that the size, the band gap, the structure, and the existence of impurity level played an important role in the photocatalytic activities

Discovery of a novel, liver-targeted thyroid hormone receptor-β agonist, CS271011, in the treatment of lipid metabolism disorders

IntroductionThyroid hormone receptor β (THR-β) plays a critical role in metabolism regulation and has become an attractive target for treating lipid metabolism disorders in recent years. Thus, in this study, we discovered CS271011, a novel THR-β agonist, and assessed the safety and efficiency of CS271011 compared to MGL-3196 in vitro and in vivo. MethodsWe conducted luciferase reporter gene assays to assess the activation of THR-β and α in vitro. C57BL/6J mice were fed a high-fat diet for 12 weeks, CS271011 was administered by gavage at the dose of 1 mg/kg and 3 mg/kg, and MGL-3196 was administered at the dose of 3 mg/kg for 10 weeks. Body weight, food intake, serum and hepatic parameters, histological analysis, pharmacokinetic studies, RNA sequencing of the liver and heart, and expression of hepatic lipid-metabolic genes were determined to evaluate the safety and efficiency of CS271011. ResultsCompared with MGL-3196, CS271011 showed higher THR-β activation in vitro. In the diet-induced obesity mice model, CS271011 demonstrated favourable pharmacokinetic properties in mice and was enriched in the liver. Finally, CS271011 improved dyslipidaemia and reduced liver steatosis in the diet-induced obesity murine model. Mechanistically, CS271011 and MGL-3196 showed potent regulation of lipid metabolism-related genes. ConclusionsCS271011 is a potent and liver-targeted THR-β agonist for treating lipid metabolism disorders

Efficient and tunable liquid crystal random laser based on plasmonic-enhanced FRET

Random lasers (RLs), which possess peculiar advantages (e.g., emission and coherence tunable) over traditional lasers with optical resonators, have witnessed rapid development in the past decades. However, it is still a challenge to tune the lasing peak of an RL over a wide range. Here, a temperature-dependent Förster resonance energy transfer (FRET) RL is demonstrated in pyrromethene 597 (PM597, “donor”) and Nile blue (NB, “acceptor”) doped chiral liquid crystals. By changing the temperature that drives the liquid crystal bandgap shift, our RL device exhibits a lasing output change from 560 nm (yellow) to 700 nm (red). While the intrinsic FRET efficiency between PM597 and NB is relatively low, the red lasing is weak. By introducing gold nanorods (GNRs) into these RL devices and utilizing GNRs’ localized surface plasmon resonance (LSPR) effect, the efficiency of FRET transfer is increased by 68.9%, thereby reducing the threshold of the RL devices. By tuning the longitudinal LSPR to match the emission wavelength of NB, the best 200-fold lasing intensity enhancement is recorded. Our findings open a pathway toward realizing LSPR-enhanced FRET tunable RLs and broaden the range of their possible exploration in photonics research and technologies

Sodium tanshinone IIA sulfonate mediates electron transfer reaction in rat heart mitochondria

In this paper, an electron transfer reaction mediated by sodium tanshinone IIA sulfonate (STS) was studied in rat heart mitochondria. It was found that STS could stimulate mitochondrial NADH oxidation dose-dependently and partly restore NADH oxidation in the presence of respiratory inhibitor (rotenone or antimycin A or KCN). It was likely that STS could accept electrons from complex I similar to ferricyanide and could be converted to its semiquinone form that could then reduce oxygen molecule. The data also showed that cytochrome c (Cyt c) could be reduced by STS in the presence of KCN, or STS could transfer the electron to oxygen directly. Free radicals were involved in the process. The results suggest that STS may protect ischemia-reperfusion injury through an electron transfer reaction in mitochondria against forming reactive oxygen radicals

The N-Terminal Penultimate Residue of 20S Proteasome α1 Influences its Nα Acetylation and Protein Levels as Well as Growth Rate and Stress Responses of Haloferax volcanii▿ †

Proteasomes are energy-dependent proteolytic machines. We elaborate here on the previously observed Nα acetylation of the initiator methionine of the α1 protein of 20S core particles (CPs) of Haloferax volcanii proteasomes. Quantitative mass spectrometry revealed this was the dominant N-terminal form of α1 in H. volcanii cells. To further examine this, α1 proteins with substitutions in the N-terminal penultimate residue as well as deletion of the CP “gate” formed by the α1 N terminus were examined for their Nα acetylation. Both the “gate” deletion and Q2A substitution completely altered the Nα-acetylation pattern of α1, with the deletion rendering α1 unavailable for Nα acetylation and the Q2A modification apparently enhancing cleavage of α1 by methionine aminopeptidase (MAP), resulting in acetylation of the N-terminal alanine. Cells expressing these two α1 variants were less tolerant of hypoosmotic stress than the wild type and produced CPs with enhanced peptidase activity. Although α1 proteins with Q2D, Q2P, and Q2T substitutions were Nα acetylated in CPs similar to the wild type, cells expressing these variants accumulated unusually high levels of α1 as rings in Nα-acetylated, unmodified, and/or MAP-cleaved forms. More detailed examination of this group revealed that while CP peptidase activity was not impaired, cells expressing these α1 variants displayed higher growth rates and were more tolerant of hypoosmotic and high-temperature stress than the wild type. Overall, these results suggest that Nα acetylation of α1 is important in CP assembly and activity, high levels of α1 rings enhance cell proliferation and stress tolerance, and unregulated opening of the CP “gate” impairs the ability of cells to overcome salt stress

Proteasomal Components Required for Cell Growth and Stress Responses in the Haloarchaeon Haloferax volcanii▿ †

Little is known regarding the biological roles of archaeal proteases. The haloarchaeon Haloferax volcanii is an ideal model for understanding these enzymes, as it is one of few archaea with an established genetic system. In this report, a series of H. volcanii mutant strains with markerless and/or conditional knockouts in each known proteasome gene was systematically generated and characterized. This included single and double knockouts of genes encoding the 20S core α1 (psmA), β (psmB), and α2 (psmC) subunits as well as genes (panA and panB) encoding proteasome-activating nucleotidase (PAN) proteins closely related to the regulatory particle triple-A ATPases (Rpt) of eukaryotic 26S proteasomes. Our results demonstrate that 20S proteasomes are required for growth. Although synthesis of 20S proteasomes containing either α1 or α2 could be separately abolished via gene knockout with little to no impact on growth, conditional depletion of either β alone or α1 and α2 together rendered the cells inviable. In contrast, the PAN proteins were not essential based on the robust growth of the panA panB double knockout strain. Deletion of genes encoding either α1 or PanA did, however, render cells more sensitive to growth on organic versus inorganic nitrogen sources and hypo-osmotic stress and limited growth in the presence of l-canavanine. Abolishment of α1 synthesis also had a severe impact on the ability of cells to withstand thermal stress. This contrasted with what was seen for panA knockouts, which displayed enhanced thermotolerance. Together, these results provide new and important insight into the biological role of proteasomes in archaea