Hen egg white lysozyme (HEWL) is widely used as a model protein for amyloid research. In this study, we aim to use Fourier transform infrared (FTIR) spectroscopy to gain new structural insights into amyloid formation of HEWL under heat and acidic condition. We reveal that the fibril-forming solution of HEWL has the capability to form fibril and oligomer with distinct β-sheet configurations under different temperatures. Amyloid fibril with parallel β-sheet configuration is formed at elevated temperature, while oligomer with antiparallel β-sheet configuration is formed at room temperature. The interplay between fibrillation and oligomerization suggests that the two β-sheet aggregates consume the same amyloidogenic materials such as peptide fragments and nicked HEWL due to lysozyme hydrolysis under heat and acidic condition. Temperature-dependent FTIR reveals that the oligomer is unstable at elevated temperature, demonstrating its off-pathway nature. The temperature-dependent formation of parallel and antiparallel β-sheet configurations discovered in lysozyme system is compared with that of amyloid-β and α-synuclein systems and the implication is discussed.
The present study examined the effect of Lactobacillus plantarum ATCC14917 fermentation on the chemical composition and antioxidant activity of apple juice. Apple juice was fermented and examined of its antioxidant activity using chemical models and cellular antioxidant assay. Furthermore, the chemical composition of fermented apple juice was characterized by LC-MS/MS. Lactobacillus plantarum ATCC14917 fermentation showed an increase in DPPH and ABTS radical scavenging activity as well as cellular antioxidant activity of apple juice. However, fermentation decreased the total phenolic and flavonoid content. Subsequent LC-MS/MS analysis of the phenolic profile indicated that the content of 5-O-caffeoylquinic acid (5-CQA), quercetin, and phloretin with strong antioxidant activity was increased significantly after fermentation. The modified phenolic composition may contribute to the increased antioxidant activity of fermented apple juice. Our findings showed that Lactobacillus plantarum ATCC14917 fermentation may be an efficient way to enhance the bioavailability of phenolic compounds and to protect cells from oxidative stress.
BackgroundNonalcoholic fatty liver disease is the most common chronic liver disease in the world, and is becoming increasingly prevalent. Saponins of sea cucumber (SSC) are proven to exhibit various biological activities. Therefore, the present study was undertaken to examine the effect of saponins extracted from sea cucumber (Pearsonothuria graeffei) on the preventive activity of fatty liver in rats.MethodsMale Wistar rats were randomly divided into five groups, including normal control group, fatty liver model group, SSC-treated group with SSC at levels of 0.01%, 0.03% and 0.05%. Model rats were established by administration with 1% orotic acid (OA). After the experiment period, serum total cholesterol (TC), triglyceride (TG), and hepatic lipid concentrations were determined. To search for a possible mechanism, we examined the changes of key enzymes and transcriptional factors involved in hepatic lipids biosynthesis, fatty acid β-oxidation.ResultsBoth 0.03% and 0.05% SSC treatment alleviated hepatic steatosis and reduced serum TG and TC concentration significantly in OA fed rats. Hepatic lipogenic enzymes, such as fatty acid synthase (FAS), malic enzyme (ME), and glucose-6-phosphate dehydrogenase (G6PDH) activities were inhibited by SSC treatment. SSC also decreased the gene expression of FAS, ME, G6PDH and sterol-regulatory element binding protein (SREBP-1c). Otherwise, the rats feeding with SSC showed increased carnitine palmitoyl transferase (CPT) activity in the liver. Hepatic peroxisome proliferator-activated receptor (PPARα), together with its target gene CPT and acyl-CoA oxidase (ACO) mRNA expression were also upregulated by SSC.ConclusionsAccording to our study, the lipids-lowering effect of dietary SSC may be partly associated with the enhancement of β-oxidation via PPARα activation. In addition, the inhibited SREBP-1c- mediated lipogenesis caused by SSC may also contribute to alleviating fatty liver.
Supplementary key words adipose tissue • cyclooxygenase • eicosanoids • extracellular signal-regulated kinase • fatty acid • infl ammation • lipaseAdipose tissue is the major repository of excess energy stored in the form of triacylglycerol (TAG). During energy need, adipocyte lipolysis involving the hydrolysis of TAG releases FFAs for energy production by different tissues ( 1, 2 ). Adipose tissue also secretes various adipokines, which infl uence energy homeostasis and insulin sensitivity of distant tissues ( 3, 4 ). In addition to its important role in metabolic regulation, adipose tissue modulates the immune system by recruiting and activating lymphoid and myeloid cells when adipocyte fat storage is exaggerated as occurs in obesity ( 5 ). In obese individuals, there is a strong positive correlation between adipocyte size and the accumulation of proinfl ammatory adipose tissue macrophages (ATMs) ( 6, 7 ).However, ATM recruitment also occurs in mice after fasting or with calorie restriction ( 8 ) and in obese patients maintained on low-calorie diets during early weight loss ( 9 ), but under these conditions, it does not associate with infl ammation. The above fi ndings suggest that the mechanisms that operate in ATM recruitment in obesity or calorie restriction are not identical. Both fasting and pharmaceutically induced lipolysis increase macrophage content in adipose tissue, and lipolysis measures correlate with increased ATM content independent of adiposity ( 10 ). This suggests that lipid turnover and not lipid accumulation per se is Abstract Obesity induces accumulation of adipose tissue macrophages (ATMs), which contribute to both local and systemic infl ammation and modulate insulin sensitivity. Adipocyte lipolysis during fasting and weight loss also leads to ATM accumulation, but without proinfl ammatory activation suggesting distinct mechanisms of ATM recruitment. We examined the possibility that specifi c lipid mediators with anti-infl ammatory properties are released from adipocytes undergoing lipolysis to induce macrophage migration. In the present study, we showed that conditioned medium (CM) from adipocytes treated with forskolin to stimulate lipolysis can induce migration of RAW 264.7 macrophages. In addition to FFAs, lipolytic stimulation increased release of prostaglandin E 2 (PGE 2 ) and prostaglandin D 2 (PGD 2 ), refl ecting cytosolic phospholipase A 2 ␣ activation and enhanced cyclooxygenase (COX) 2 expression. Reconstituted medium with the anti-infl ammatory PGE 2 potently induced macrophage migration while different FFAs and PGD 2 had modest effects. The ability of CM to induce macrophage migration was abolished by treating adipocytes with the COX2 inhibitor sc236 or by treating macrophages with the prostaglandin E receptor 4 antagonist AH23848. In fasted mice, macrophage accumulation in adipose tissue coincided with increases of PGE 2 levels and COX1 expression. Collectively, our data show that adipocyte-originated PGE 2 with infl ammation suppressive properties plays a signifi cant rol...
Advanced glycation end products (AGEs) could interact with the receptor for AGE (RAGE) as a sterile danger signal to induce inflammation. 4′-methoxyresveratrol (4′MR), a polyphenol derived from Dipterocarpaceae, has not been studied for its anti-inflammation effects. In the present study, we sought to explore the protective role of 4′MR in AGEs-induced inflammatory model using RAW264.7 macrophages. 4′MR significantly inhibited gene expression of pro-inflammatory cytokines and chemokines, such as interleukin 1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α) and monocyte chemoattractant protein-1 (MCP-1), as well as two typical pro-inflammatory enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2). Besides, 4′MR significantly decreased oxidative stress, demonstrated by levels of ROS production, protein carbonyl and advanced oxidation protein product via down-regulation of NADPH oxidase. Further analysis showed that 4′MR attenuated the RAGE overexpression induced by MGO-BSA. It also blocked the downstream signal of AGE-RAGE, particularly, MAPKs including p38 and JNK, and subsequently reduced NF-κB activation. Additionally, 4′MR significantly abated the activation of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome including NLRP3 and cleaved caspase-1 and reduced the secretion of mature IL-1β. Taken together, our results suggest that the anti-inflammatory effect of 4′MR is mainly through suppressing RAGE-mediated MAPK/NF-κB signaling pathway and NLRP3 inflammasome activation. 4′MR could be a novel therapeutic agent for inflammation-related diseases.
In this paper, we propose a novel method for finger-vein recognition. We extract the features of the vein patterns for recognition. Then, the minutiae features included bifurcation points and ending points are extracted from these vein patterns. These feature points are used as a geometric representation of the vein patterns shape. Finally, the modified Hausdorff distance algorithm is provided to evaluate the identification ability among all possible relative positions of the vein patterns shape. This algorithm has been widely used for comparing point sets or edge maps since it does not require point correspondence. Experimental results show that these minutiae feature points can be used to perform personal verification tasks as a geometric representation of the vein patterns shape. Furthermore, by this developed method, we can achieve robust image matching under different lighting conditions.
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