Acetyl-L-carnitine protects adipose-derived stem cells exposed to H2O2 through regulating AMBRA1-related autophagy

The cell activity of adipose-derived stem cells(ADSCs)is affected by the intracellular reactive oxygen species(ROS)and the level of autophagy.Previous studies reveal that acetyl-L-carnitine(ALC)possesses capacities of resisting oxidative stress and regulating autophagy.Activating molecule in Beclin1-regulated autophagy protein 1(AMBRA1)plays a key role in initiating Beclin1-regulated autophagy.In the present study,we discovered ALC pretreatment(1 mM,24 h)significantly increased the activity of ADSCs exposed to H_(2)O_(2)(100μM,2 h)in vitro with improved stemness,and reduced the production of intracellular ROS.In addition,we found for the first time that ALC treatment up-regulated autophagy of ADSCs through strengthening the expressions of Beclin1 and AMBRA1 synchronously,which might be involved in the protective effect of ALC.

Effects of HMW-GS Dx2 absence on the protein aggregation characteristics and thermal stability of wheat flour during maturation

Background:Wheat flour maturation affects the aggregation and structural stability of proteins.The number of high-molecular-weight glutenin subunits(HMW-GSs)differs in various wheat varieties.The effects of Dx2 absence on the protein aggregation characteristics and thermal sta-bility of flour were investigated during 120 d of maturation using near-isogenic lines(NILs).Results:The absence of Dx2 delayed and decreased the protein aggregation of flours during maturation,i.e.the maturation-induced increases were later and smaller for glutenin,glutenin macropolymer(GMP),glutenin/gliadin ratio,β-sheets,andβ-sheet/a-helix ratio in HMW-D1a without Dx2 than in HMW-D1p with Dx2;these differences were ascribed to the weaker interactions between the sulfhydryl(-SH)groups,disulfide bonds(-S-S-),and hydrophobicity in the flours without Dx2.Flour maturation caused the dough microstructures to be more compact and denser,thereby increasing the flour thermal stability as observed by a higher denaturation peak temperature(Tp),enthalpy of thermal transition(△H),and degradation temperature(Td),These changes led to better dough properties such as dough development time,dough stability time,and protein weakening,but the optimal stage in HMW-D1a without Dx2was reached later.Conclusion:These findings deepen the understanding of how HMW-GS Dx2 modifies protein structures during flour maturation.

A Co-N/C hollow-sphere electrocatalyst derived from a metanilic CoAl layered double hydroxide for the oxygen reduction reaction, and its active sites in various pH media

Transition-metal-coordinating nitrogen-doped carbon catalysts （M-N/C, M = Co, Fe, Mn, Ni, etc.） are considered one of the most promising nonprecious-metal electrocatalysts for the oxygen reduction reaction （ORR）. However, they suffer from low ORR catalytic activity, and their active sites have not been fully identified. Herein, we report the synthesis of a porous Co-N/C hollow-sphere electrocatalyst by carbonization of metanilic anions between the layers of a Co-A1 layered double hydroxide. The as-prepared Co-N/C catalyst exhibited excellent ORR catalytic activity with a high half-wave potential and a large diffusion-limited current in alkaline and neutral solutions. The performance of the catalyst was comparable to those of commercial Pt/C electrocatalysts. Through investigating the effects of mask ions （SCN- and F-） on the ORR activity of the Co-N/C catalyst, and comparing the ORR activity before and after the destruction of Co-Nx sites in different pH media, we concluded that the Co-Nx sites act directly as the ORR active sites in acidic and neutral solutions, but have a negligible effect on the ORR activity in alkaline conditions.