Improvement of solubility, gelation and emulsifying properties of myofibrillar protein from mantis shrimp (Oratosquilla oratoria) by phosphorylation modification under low ionic strength of KCl.

The objective of this study was to investigate the mechanisms of phosphates coupled with KCl (at 0, 0.01 and 0.03 M) affecting gel and emulsifying properties of myofibrillar protein (MP) from mantis shrimp. 31P NMR showed that phosphate groups were introduced to MP after treatment with sodium pyrophosphate (SPP) or sodium tripolyphosphate (STPP). The incorporation of phosphates enhanced electronegativity and solubility of MP, leading to exposure of hydrophobic groups, especially in the presence of 0.03 M KCl. These changes resulted in increased gel strength, water-holding capacity and elasticity of MP, mainly due to the improved cross-linking of proteins via ionic interaction, hydrophobic interaction and disulfide bonds. Furthermore, the combination of phosphate and KCl contributed to formation of more stable emulsions stabilized by MP with higher emulsifying activity and smaller droplet size. These results indicated that phosphates and low-dose sodium substitutes synergistically improved the processing properties of muscle food.

Purification of novel antioxidant peptides from myofibrillar protein hydrolysate of chicken breast and their antioxidant potential in chemical and H2O2-stressed cell systems.

Myofibrillar protein accounting for about 60% of total muscle proteins is expected to be a promising source of bioactive peptides. The purpose of the present study was to purify antioxidant peptides from myofibrillar protein hydrolysate of chicken breast by ultrafiltration and gel filtration chromatography, and evaluate their chemical antioxidant activities and protective effects in H2O2-stressed NIH-3T3 cells. Four major peptides were identified using nano-LC-ESI-MS/MS as ITTNPYDY, IGWSPLGSL, ITTNPYDYHY, and LRVAPEEHPTL. The sequenced peptides were synthesized and exhibited remarkable radical-scavenging ability, ORAC (108.2-133.5 µM TE per mg peptide), and FRAP (75.4-92.5 mM Fe2+ per mg peptide). Structure-activity relationship indicated that the antioxidant capacity of the peptides was more related to the presence of hydrophobic and antioxidant amino acids (including Trp, Val, Ile, Leu, Ala, Pro, Gly, Asp, His, and Tyr) in the sequences as well as their molecular structures. Moreover, they protected NIH-3T3 cells against oxidative damage through inhibiting ROS generation and lipid peroxidation. Especially, the antioxidant peptides ITTNPYDY and IGWSPLGSL significantly (p < 0.05) elevated intracellular glutathione level and antioxidant enzyme activities, and suppressed apoptosis by blocking caspase-3 activation. This work highlights that the selected peptides may serve as functional food ingredients with antioxidant and cytoprotective characteristics.

Cationic IrIII Emitters with Near-Infrared Emission Beyond 800†nm and Their Use in Light-Emitting Electrochemical Cells.

Solid-state near-infrared (NIR) light-emitting devices have recently received considerable attention as NIR light sources that can penetrate deep into human tissue and are suitable for bioimaging and labeling. In addition, solid-state NIR light-emitting electrochemical cells (LECs) have shown several promising advantages over NIR organic light-emitting devices (OLEDs). However, among the reported NIR LECs based on ionic transition-metal complexes (iTMCs), there is currently no iridium-based LEC that displays NIR electroluminescence (EL) peaks near to or above 800 nm. In this report we demonstrate a simple method for adjusting the energy gap between the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO) of iridium-based iTMCs to generate NIR emission. We describe a series of novel ionic iridium complexes with very small energy gaps, namely NIR1-NIR6, in which 2,3-diphenylbenzo[g]quinoxaline moieties mainly take charge of the HOMO energy levels and 2,2'-biquinoline, 2-(quinolin-2-yl)quinazoline, and 2,2'-bibenzo[d]thiazole moieties mainly control the LUMO energy levels. All the complexes exhibited NIR phosphorescence, with emission maxima up to 850 nm, and have been applied as components in LECs, showing a maximum external quantum efficiency (EQE) of 0.05 % in the EL devices. By using a host-guest emissive system, with the iridium complex RED as the host and the complex NIR3 or NIR6 as guest, the highest EQE of the LECs can be further enhanced to above 0.1 %.

Health risk assessment of heavy metals via dietary intake of wheat grown in Tianjin sewage irrigation area.

The possible health risks from heavy metal (Zn, Cu, Cr, Ni, Pb, and Cd) contamination to the local population through the food chain were evaluated in Tianjin, China, a city with a long history of sewage irrigation. Results showed that the continuous application of wastewater has led to an accumulation of heavy metals in the soil, and 54.5 and 18.25% soil samples accumulated Cd and Zn in concentrations exceeding the permissible limits in China. Concentrations of heavy metals in wheat grain decreased in the order of Zn > Cu > Cr > Ni > Pb > Cd, and transfer factors for the six heavy metals showed the trend as Zn > Cd > Cu > Pb > Cr > Ni. The risk assessment for the six heavy metals through wheat consumption suggests that concentrations of Cr and Cd in some wheat samples exceed their reference oral dose for adults and children. In general, no target hazard quotient value of any individual element was greater than one, which means they are within the safe interval. However, 36.4 and 63.6% hazard index values for adults and children were greater than one, respectively. The health risk due to the added effects of heavy metals was significant for children and adults, and more attention should be paid tothe potential added threat fromheavy metals to the health of children via dietary intake of wheat in Tianjin.

Urinary angiopoietin-2 is associated with albuminuria in patients with type 2 diabetes mellitus.

Aims. To evaluate the levels of angiopoietin-1 (Ang-1), Ang-2, and vascular endothelial growth factor (VEGF) in serum and urine, and their association with albuminuria in patients with type 2 diabetes mellitus. Methods. In 113 type 2 diabetic patients with normoalbuminuria, microalbuminuria, and macroalbuminuria and 30 healthy controls, the levels of Ang-1, Ang-2, and VEGF in serum and urine were measured by enzyme-linked immunosorbent assay (ELISA). Results. Urinary and serum levels of Ang-2 were significantly higher in diabetic patients with normoalbuminuria than in healthy controls. Increased urinary Ang-2 level was positively associated with the degree of albuminuria. Urinary Ang-1 levels were significantly higher in normoalbuminuria patients and lower in macroalbuminuria patients than in controls. The levels of urinary VEGF increased in the albuminuria subgroup, though serum levels of Ang-1 and VEGF did not change. Urinary Ang-2 levels were correlated positively with albuminuria and negatively with glomerular filtration rate (GFR). Stepwise multiple regression analysis identified albuminuria (P < 0.001) and GFR (P = 0.001) as significant predictors of urinary Ang-2. Conclusions. Our data suggest that urinary Ang-2 is stepwise increased with renal damage in patients with type 2 diabetes mellitus and is associated with albuminuria.