L-Theanine attenuates heat stress-induced proteotoxicity and alterations in carbohydrate and lipid metabolism via heat shock factor 1.

Extreme heat caused by global warming accelerated the frequency of heat stress (HS). Proteotoxic stress induced by the aggregation of misfolded proteins and metabolic stress triggered by alterations in the metabolism were observed during HS. The activation of heat shock factor 1 (Hsf1) and its interaction with adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) are critical in addressing proteotoxicity and metabolic stress in heat-stressed organisms. Previous studies have shown that L-theanine (LTA) can regulate nutrient metabolism through the AMPK pathway and can alleviate HS. Therefore, we hypothesize that LTA may help in restoring homeostasis by regulating nutrient metabolism under HS. Here, we investigated the effects of LTA on nutrient metabolism in heat-stressed rats and characterized the underlying mechanisms using RNA sequencing and metabonomics. The results showed that LTA alleviated HS-induced liver damage, promoted body weight gain, decreased serum cortisol and enhanced the total protein content. Besides, it regulated the expression of genes related to carbohydrate, lipid and amino acid metabolism and altered metabolite levels. Moreover, LTA inhibited the expression of Hsf1 and heat shock protein 70 (Hsp70), promoted AMPK phosphorylation and the expression of glucose-6-phosphatase catalytic subunit 1 (G6pc), and inhibited the phosphorylation of acetyl-CoA carboxylase 1 (ACC1) in heat-stressed rats. Mechanistically, LTA alleviated HS-induced proteotoxic stress by acting on Hsf1/Hsp70; simultaneously, it promoted AMPK phosphorylation by suppressing Hsf1 expression, which in turn inhibited fatty acid synthesis and hepatic gluconeogenesis, thus alleviating HS-induced metabolic stress. These results suggest that LTA regulates nutrient metabolism through Hsf1/AMPK and alleviates HS-induced proteotoxicity via Hsf1/Hsp70.

Nitrogen and Sulfur Co-doped Carbon Dots as a Turn-Off Fluorescence Probe for the Detection of Cerium and Iron.

Carbon dots has becoming one of the most promising fluorescence sensors to determine the trace level of heavy metals in environments because of their advantages in optical properties, response time, and convenient operation procedures. Herein, a novel nitrogen and sulfur co-doped carbon dots (NS-CDs) were prepared though microwave assisted approach using DL-malic acid and allyl thiourea for the first time. Due to the existence of nitrogen and sulfur, the as-prepared NS-CDs exhibited bright blue fluorescence at 430 nm upon 330 nm excitation, with a fluorescence quantum yield of 19.8%. The sensitivity study of NS-CDs against metal ions and organic molecules has approved that the fluorescence could be further quenched by Ce4+ and Fe3+ ions, with the same linear detection ranges varying from 10 to 90 µM. The limits of detection (LOD) were determined as low as 0.75 µM and 0.67 µM for Ce4+ and Fe3+ ions, respectively. The possible quenching mechanism is explained by inner filter effect and static quenching mechanism for Ce4+ ions, while the quenching effect caused by Fe3+ ions is attributed to the inner filter effect, static and dynamic quenching mechanisms. Additionally, the developed sensor was used for the detection of Ce4+ and Fe3+ ions in tap water with satisfactory recoveries. Finally, the designed NS-CDs sensor possesses good biocompatibility against MA104 cells, suggesting the sensor can be potentially applied to detect Ce4+ and Fe3+ ions in environment and biological systems.

Improved hydrogen storage properties of MgH2 by nickel@nitrogen-doped carbon spheres.

Magnesium hydride is considered to be one of the most desirable hydrogen storage materials due to its high weight capacity (7.6 wt% H2) and low price. However, its relatively high operating temperatures and slow dynamics have always hampered its commercial applications. In this paper, nano-nickel particle coated nitrogen-doped carbon spheres (Ni@NCS) were synthesized by a chemical reduction method and then introduced into Mg to form an MgH2-Ni@NCS composite via hydriding combustion and subsequent high-energy ball milling processes. The results showed that the MgH2-Ni@NCS composite possessed high hydrogen storage capacity and fast absorbing/desorbing kinetics, absorbing 5.7 wt% H2 and desorbing 4.3 wt% H2 within 8 min at 623 K. Moreover, the capacity shows negligible degradation after 10 cycles, indicating that the MgH2-Ni@NCS composite has good cycling stability. Even at relatively low temperature (373 K), the MgH2-Ni@NCS composite still absorbed 4.2 wt% H2 within 60 min compared to 0.9 wt% H2 for milled MgH2. The improvement in hydrogen storage properties is ascribed to the in situ formed Mg2NiH4 induced dehydrogenation of MgH2 and effective prevention of the agglomeration of magnesium during the hydriding/dehydriding reaction by the carbon material.

Enhanced H2 sorption performance of magnesium hydride with hard-carbon-sphere-wrapped nickel.

Magnesium hydride is regarded as one of the most ideal candidates for hydrogen storage, but its relatively high operating temperatures and slow kinetics always hinder its commercial applications. Herein, we first fabricated hard-carbon-sphere-wrapped Ni (Ni/HCS) via a mild chemical method; subsequently, the as-prepared additive was introduced to fabricate an Mg-Ni/HCS composite by using hydriding combustion synthesis. Hard carbon spheres (HCS) effectively inhibited the agglomeration of hydride particles during hydrogen storage cycling; they could also provide active sites to promote the nucleation of Mg-based hydrides. During the hydriding combustion synthesis procedure, in situ-formed Mg2NiH4 could induce the absorption of MgH2, thus triggering its hydrogen properties. Remarkable enhancement in hydrogen absorption properties of the composite was found. The composite absorbed 6.0 wt% H2 within 5 min at 275 °C; moreover, even at 75 °C, it could still absorb 3.5 wt% H2. Furthermore, it delivered a high reversible hydrogen absorption capacity of 6.2 wt% and excellent rate capability at 350 °C. It was also demonstrated that the composite could release 6.2 wt% H2 at 350 °C within 5 min. A rather low activation energy value (65.9 kJ mol-1) for the dehydrogenation of MgH2 was calculated as compared to that for commercial MgH2 (133.5 kJ mol-1).

Ultrasensitive electrochemical detection of tumor cells based on multiple layer CdS quantum dots-functionalized polystyrene microspheres and graphene oxide - polyaniline composite.

In this work, a novel ultrasensitive electrochemical biosensor was developed for the detection of K562 cell by a signal amplification strategy based on multiple layer CdS QDs functionalized polystyrene microspheres(PS) as bioprobe and graphene oxide(GO) -polyaniline(PANI) composite as modified materials of capture electrode. Due to electrostatic force of different charge, CdS QDs were decorated on the surface of PS by PDDA (poly(diallyldimethyl-ammonium chloride)) through a layer-by-layer(LBL) assemble technology, in which the structure of multiple layer CdS QDs increased the detection signal intensity. Moreover, GO-PANI composite not only enhanced the electron transfer rate, but also increased tumor cells load ratio. The resulting electrochemical biosensor was used to detect K562 cells with a lower detection limit of 3 cellsmL-1 (S/N = 3) and a wider linear range from 10 to 1.0 × 107 cellsmL-1. This sensor was also used for mannosyl groups on HeLa cells and Hct116 cells, which showed high specificity and sensitivity. This signal amplification strategy would provide a novel approach for detection, diagnosis and treatment for tumor cells.

Effect of Yikun Neiyi Wan on the expression of aromatase P450, COX-2, and ER related receptor in endometrial cells in vitro from patients with endometriosis.

OBJECTIVE: To investigate the effect of yikun neiyi wan (YKNYW) and gestrinone on the expression of aromatase P450 (P450arom), cyclo-oxygenase-2 (COX-2) and estrogen receptor (ER) in isolated ectopic and normal endometrial stroma cells in vitro. METHODS: Digestion and serial filtration were used to isolate and culture the ectopic and eutopic endometrial cells from patients with chocolate cyst in virto. Transformation of the cell morphology was observed in a inverted microscope. The effect of YKNYW on the expression of aromatase P450, cyclo-oxygenase-2, estrogen receptor in cultured endometriosis cells were detected by immunohistochemical method. RESULTS: The expression levels of P450arom, COX-2 in glandular epithelium cells in vitro were decreased significantly by YKNYW compared with gestrinone (P < 0.05). ER expression in mesenchymal cells of endometriosis was increased by YKNYW in the large and medium dosage groups compared with gestrinone. CONCLUSION: The mechanism by which YKNYW alleviates endometriosis pain is possibly related to the decrease in ectopic endometrial P450 arom and COX-2 expression in glandular epithelium, contrary to gestrinone, and the increase in ER expression in mesenchymalis, consistent with gestrione in patients with endometriosis.