Efficient heavy metal removal from water by alginate-based porous nanocomposite hydrogels: The enhanced removal mechanism and influencing factor insight.

Novel porous alginate-based nanocomposite hydrogels were prepared by incorporating polyaniline-polypyrrole modified graphene oxide (GO@PAN-PPy) as reinforcing fillers into the alginate matrix (GO@PAN-PPy/SA) for Cr(VI) and Cu(II) removal from water. Different in-situ co-polymerization functionalized GO with Py-to-An mass ratios of monomers (from nil to 1:1) and contents of GO@PAN-PPy (from nil to 2.0%(w/v)) were embedded into the alginate backbone to improve the sorption performance. Key factors, such as pH, coexisting metal ions, and swelling states were investigated in batch adsorption modes. The synergistic effect combined from polymer backbone and fillers could lower the impact of the pH-dependent adsorption reaction. With an adsorption ability superior to that of plain SA and GO/SA, the optimized GO@PAN-PPy-2(1)/SA exhibited good experimental maximum adsorption capacities for Cr(VI) (~133.7 mg/g) and Cu(II) (~87.2 mg/g) at pH 3.0, which were better than those of many other similar sorbents. The sorbents possessed excellent adaptability for 0.2 M salt for Cr(VI) removal but poor for Cu(II) removal. Pre-swelling treatment and co-adsorption could enhance the adsorption performance. The excellent reusability of hydrogel was demonstrated after five cycles in single/binary system. Overall, this work reveals that the resultant hydrogel holds potential as candidate sorbent to remove anionic-cationic heavy metal ions from water.

Glutamine synthetase and glutamate dehydrogenase contribute differentially to proline accumulation in leaves of wheat (Triticum aestivum) seedlings exposed to different salinity.

To investigate the roles of ammonium-assimilating enzymes in proline synthesis under salinity stress, the activities of glutamine synthetase (GS; EC 6.3.1.2) and NADH-dependent glutamate dehydrogenase (NADH-GDH; EC 1.4.1.2) were determined in leaves of wheat (Triticum aestivum) seedlings exposed to salt stress at 150 and 300 mM NaCl for 5d. At the lower salinity, only GS activity increased markedly. At 300 mM NaCl, however, NADH-GDH activity increased while GS activity decreased. A significant accumulation of proline was found only at high-salinity exposure while glutamate, a proline precursor, increased dramatically under both low and high salinity. These data suggests that GS-catalysis might be the main glutamate synthesis pathway under low salinity. At 300 mM NaCl, glutamate seems to be preferentially produced through the process catalyzed by NADH-GDH. The increase of ammonium in salinity-stressed wheat seedlings might have resulted from increased photorespiration, which is responsible for the higher NADH-GDH activity. The activity of Delta(1)-pyrroline-5-carboxylate reductase (P5CR; EC 1.5.1.2) was significantly enhanced at 300 mM NaCl but remained unchanged at 150 mM. Delta(1)-Pyrroline-5-carboxylate synthetase (P5CS) activity did not show a specific response, indicating that P5CR might be the limiting step in proline synthesis from glutamate at high salinity.

Targeting autophagy in multiple myeloma.

Autophagy plays an important role in plasma cell ontogeny and in the pathophysiology of multiple myeloma. Autophagy is usually considered a pro-survival mechanism, and cooperates with the ubiquitin proteasome system in maintaining the homeostasis of myeloma cells by degrading excessive and misfolded proteins for energy recycling. Therefore, the inhibition of autophagy could effectively induce death in myeloma cells, and could synergize with proteasome inhibitors. However, the excessive activation of autophagy could also lead to the extreme degradation of the organelles that induce autophagic cell death. Hence, the activation of autophagic cell death might also represent a promising approach for treating myeloma. Recent studies have demonstrated that autophagy also mediates drug resistance in myeloma cells and the complications of myeloma, while the inhibition of autophagy may reverse the response to drugs. In this study, we have mainly reviewed recent research on autophagy in relationship to the therapeutic effect, the reversal of drug resistance, and the mediation of complications.