In order to evaluate the high-value application of squid by-products yielded hydrolysate, the process of preparation and purification technology, chemical composition and in vitro antioxidant ...activity of the hydrolysate were investigated. The optimal conditions of papain hydrolysis were obtained by single-factor experiments and orthogonal test with the DPPH• scavenging ratio as index, amino acid composition was analysed by automatic amino acid analyzer, the hydrolysate was isolated with a Sephadex G-25 column. Based on single-factor experiments, the hydrolysate with the DPPH• scavenging ratio being 53.96 % was gained under the optimal condition of enzymolysis temperature of 45 °C, enzymolysis time of 3 h, total enzyme dose of 1.2 %, and the pH value of 7. The protein content of the hydrolysate reached up to 17.53 %, and the essential amino acids were accounted for 51.06 % of total amino acids. The largest content amino acid was glutamic acid, which accounted for 10.74 % of total amino acids. Compared with the amino acid profiles recommended by FAO/WHO, the quality of the protein hydrolysate was high, as it was rich in essential amino acids, including isoleucine, leucine, lysine, methionine and cystine, threonine, tryptophan, and valine, which covered 88 %-100 % of the FAO/WHO recommended. The hydrolysate was divided into three fractions (F1-F3) using a Sephadex G-25 column, the F1 possessed the highest antioxidation activity with the reducing power, •OH and DPPH• scavenging ratio being 0.236, 18.13 % and 63.85 % at the concentration of 5 mg/mL. Compared with the retention time of the reduced glutathione chromatomap, the relative molecular mass of F1 was higher than 307, F2 and F3 was lower than 307. The result revealed that the protein hydrolysate from squid by-products by papain had strongly antioxidant capacity in vitro and high nutrition, and this finding provided a new way of advanced exploitation of squid scrap resources.
Organoselemium compounds possess strong antioxidant activity as well as protecting cells from DNA damage, mitochondrial injury, lipid peroxidation, protein denaturation and cell death. Herein, we ...used an in vitro oxidative model to further investigate the antioxidant effects of a novel organoselemium compound, low molecular-weight seleno-aminopolysaccharides (LSA) in intestinal porcine epithelial cells (IPEC-1), and the molecular mechanisms of these effects. Analysis by MTT assay showed that LSA could significantly increase the viability of IPEC-1 cells compared to cells exposed to H
O
. We found that the levels of different antioxidant enzymes could dramatically increase in LSA pretreatment group compared to H
O
treatment group. Furthermore, LSA significantly increased the gene expression of antioxidant enzymes and phase 2 detoxifying enzymes in IPEC-1 cells, as measured by qRT-PCR. In addition, LSA up-regulated the expression level of intracellular transcription factor NF-E2-related factor 2 (Nrf2) and inhibited the level of kelch-like ECH-associated protein 1 (Keap1) with western blot analysis. Collectively, the present study suggested that LSA has the protective effect of IPEC-1 cells against H
O
-induecd oxidative stress, and its mechanism may be related to activation of Keap1/Nrf2 signaling pathway in intestinal epithelial cells.
The optimal conditions of microwave-assisted extraction (MAE) and papain hydrolysis processes were explored by using single-factor experiments and orthogonal array design with the extraction ratio ...and purity of polysaccharides as indexes. Under the optimal extraction conditions of microwave power 500 W, sodium hydroxide concentration 12 %, irradiation time 5 min, and solvent to material ratio 40 ml/g, the yield of glycosaminoglycans (GAGs) from the cartilage of D. akajei was 13.87 ± 0.64 %. The optimum conditions of enzymatic hydrolysis was temperature 45°C, pH 6.8, time 4 h and enzyme amount 1.0 %. Under the optimal condition, the purity of polysaccharide reached to 89.57 % ± 2.17 %. The antioxidant activities tests indicated both the GAGs and chondroitin sulfate had noticeable effects on scavenging free radicals, especially at high addition quantity. The results suggest that the polysaccharide purified from the cartilage of D. akajei has good potential as a natural antioxidant used in food and/or medicine industries.
Vinylcyclopropanes (VCPs) are commonly used in transition‐metal‐catalyzed cycloadditions, and the utilization of their recently realized reactivities to construct new cyclic architectures is of great ...significance in modern synthetic chemistry. Herein, a palladium‐catalyzed, visible‐light‐driven, asymmetric 5+2 cycloaddition of VCPs with α‐diazoketones is accomplished by switching the reactivity of the Pd‐containing dipolar intermediate from an all‐carbon 1,3‐dipole to an oxo‐1,5‐dipole. Enantioenriched seven‐membered lactones were produced with good reaction efficiencies and selectivities (23 examples, 52–92 % yields with up to 99:1 er and 12.5:1 dr). In addition, computational investigations were performed to rationalize the observed high chemo‐ and periselectivities.
By switching the reactivity of Pd‐containing dipolar intermediates from all‐carbon 1,3‐dipoles to oxo‐1,5‐dipoles, Pd‐catalyzed asymmetric 5+2 cycloadditions of vinylcyclopropanes (VCPs) with photogenerated ketenes are achieved. A variety of chiral seven‐membered lactone‐fused polycyclic molecules are produced with good reaction efficiency and selectivity.
Abstract Background Irisin is a novel exercise-induced myokine involved in the regulation of adipose browning and thermogenesis. In this study, we investigated the potential role of irisin in ...cerebral ischemia and determined whether irisin is involved in the neuroprotective effect of physical exercise in mice. Materials and Methods The middle cerebral artery occlusion (MCAO) model was used to produce cerebral ischemia in mice. First, the plasma irisin levels and changes in expression of the irisin precursor protein FNDC5 in skeletal muscle were determined post ischemic stroke. Second, the association between plasma irisin levels and the neurological deficit score, brain infarct volume, or plasma concentrations of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1β in mice with MCAO were evaluated. Third, the therapeutic effect of irisin on ischemic brain injury was evaluated in vivo and in vitro. Recombinant irisin was injected directly into the tail vein 30 min after the MCAO operation, and then the effects of irisin treatment on brain infarct volume, neurological deficit, neuroinflammation, microglia activation, monocyte infiltration, oxidative stress and intracellular signaling pathway activation (Akt and ERK1/2) were measured. Irisin was also administered in cultured PC12 neuronal cells with oxygen and glucose deprivation (OGD). Finally, to assess the potential involvement of irisin in the neuroprotection of physical exercise, mice were exercised for 2 weeks and an irisin neutralizing antibody was injected into these mice to block irisin 1 h before the MCAO operation. Results The plasma irisin concentration and intramuscular FNDC5 protein expression decreased after ischemic stroke. Plasma irisin levels were negatively associated with brain infarct volume, the neurological deficit score, plasma TNF-α and plasma IL-6 concentrations. In OGD neuronal cells, irisin protected against cell injury. In mice with MCAO, irisin treatment reduced the brain infarct volume, neurological deficits, brain edema and the decline in body weight. Irisin treatment inhibited activation of Iba-1+ microglia, infiltration of MPO-1+ monocytes and expression of both TNF-α and IL-6 mRNA. Irisin significantly suppressed the levels of nitrotyrosine, superoxide anion and 4-hydroxynonenal (4-HNE) in peri-infarct brain tissues. Irisin treatment increased Akt and ERK1/2 phosphorylation, while blockade of Akt and ERK1/2 by specific inhibitors reduced the neuroprotective effects of irisin. Finally, the exercised mice injected with irisin neutralizing antibody displayed more severe neuronal injury than the exercised mice injected with control IgG. Conclusion Irisin reduces ischemia-induced neuronal injury via activation of the Akt and ERK1/2 signaling pathways and contributes to the neuroprotective effect of physical exercise against cerebral ischemia, suggesting that irisin may be a factor linking metabolism and cardio-cerebrovascular diseases.
Summary
In agricultural soils, amino acids can represent vital nitrogen (N) sources for crop growth and yield. However, the molecular mechanisms underlying amino acid uptake and allocation are poorly ...understood in crop plants. This study shows that rice (Oryza sativa L.) roots can acquire aspartate at soil concentration, and that japonica subspecies take up this acidic amino acid 1.5‐fold more efficiently than indica subspecies. Genetic association analyses with 68 representative japonica or indica germplasms identified rice Lysine‐Histidine‐type Transporter 1 (OsLHT1) as a candidate gene associated with the aspartate uptake trait. When expressed in yeast, OsLHT1 supported cell growth on a broad spectrum of amino acids, and effectively transported aspartate, asparagine and glutamate. OsLHT1 is localized throughout the rice root, including root hairs, epidermis, cortex and stele, and to the leaf vasculature. Knockout of OsLHT1 in japonica resulted in reduced root uptake of amino acids. Furthermore, in 15N‐amino acid‐fed mutants versus wild‐type, a higher percentage of 15N remained in roots instead of being allocated to the shoot. 15N‐ammonium uptake and subsequently the delivery of root‐synthesized amino acids to Oslht1 shoots were also significantly decreased, which was accompanied by reduced shoot growth. These results together provide evidence that OsLHT1 functions in both root uptake and root to shoot allocation of a broad spectrum of amino acids in rice.
Significance Statement
Amino acids can serve as important nitrogen sources in agricultural fields, but little is known about the underlying mechanisms of amino acid uptake and allocation in crops. This study conducted genetic association analyses of 15N‐aspartate uptake among rice accessions, combined with genetic and biochemical analyses, and revealed that Oryza sativa Lysine‐Histidine‐type Transporter 1 (OsLHT1) functions in both root uptake and root to shoot allocation of a broad spectrum of amino acids.
•Electric bus fleet scheduling considering battery fading mechanism.•Electric bus fleet scheduling considering non-linear charging profile.•A case study shows a massive reduction in cost (10.1 – ...27.3% savings).•The model can help transit operators for more cost-effective plans.
This study aims to determine the battery electric bus service and charging strategy to minimize the total operational cost of transit system, where the cost incurred by battery degradation and non-linear charging profile is taken into account. We formulate a set partitioning model for this problem, subject to predefined trip schedule and limited charging facilities. A tailored branch-and-price approach is then proposed to find the global optimal solution. In particular, we develop an effective multi-label correcting method to deal with the pricing problem (i.e., generating columns) in column generation procedure within the branch-and-price framework, coupled with a dual stabilization technique with an aim to accelerate the convergence rate. Meanwhile, a branch-and-bound solution approach is adopted to guarantee optimal integer solutions. Numerical experiments and a case study arising from real transit network are conducted to further assess the efficiency and applicability of the proposed method. Our experiments confirm that, despite the complexity of the considered problem, optimal solution can still be generated within reasonable computational time using the proposed algorithm. The results also show considerable cost saving (about 10.1–27.3% less) if this optimization model is implemented, mainly contributed by the substantial extension of battery life. A number of managerial insights stemmed from the numerical case study are outlined, which can help transit operators formulate more cost-efficient electric bus fleet scheduling plans.
PDF
