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Sarcopenia, a decrease in skeletal muscle mass and function caused by aging, impairs mobility, raises the risk of fractures, diabetes, and other illnesses, and severely affects a senior’s quality of life. Nobiletin (Nob), polymethoxyl flavonoid, has various biological effects, such as anti-diabetic, anti-atherogenic, anti-inflammatory, anti-oxidative, and anti-tumor properties. In this investigation, we hypothesized that Nob potentially regulates protein homeostasis to prevent and treat sarcopenia. To investigate whether Nob could block skeletal muscle atrophy and elucidate its underlying molecular mechanism, we used the D-galactose-induced (D-gal-induced) C57BL/6J mice for 10 weeks to establish a skeletal muscle atrophy model. The findings demonstrated that Nob increased body weight, hindlimb muscle mass, lean mass and improved the function of skeletal muscle in D-gal-induced aging mice. Nob improved myofiber sizes and increased skeletal muscle main proteins composition in D-gal-induced aging mice. Notably, Nob activated mTOR/Akt signaling to increase protein synthesis and inhibited FOXO3a-MAFbx/MuRF1 pathway and inflammatory cytokines, thereby reducing protein degradation in D-gal-induced aging mice. In conclusion, Nob attenuated D-gal-induced skeletal muscle atrophy. It is a promising candidate for preventing and treating age-associated atrophy of skeletal muscles.

Increasing hepcidin expression is a vital factor in iron homeostasis imbalance among patients with chronic kidney disease (CKD). Recent studies have elucidated that abnormal serum steroid levels might cause the elevation of hepcidin. Glycochenodeoxycholate (GCDCA), a steroid, is significantly elevated in patients with CKD. However, the correlation between GCDCA and hepcidin has not been elucidated. Decreased serum iron levels and increased hepcidin levels were both detected in patients with CKD in this study. Additionally, the concentrations of GCDCA in nephropathy patients were found to be higher than those in healthy subjects. HepG2 cells were used to investigate the effect of GCDCA on hepcidin in vitro. The results showed that hepcidin expression increased by nearly two-fold against control under 200 μM GCDCA treatment. The phosphorylation of SMAD1/5/8 increased remarkably, while STAT3 and CREBH remained unchanged. GCDCA triggered the expression of farnesoid X receptor (FXR), followed with the transcription and expression of both BMP6 and ALK3 (upward regulators of SMAD1/5/8). Thus, GCDCA is a potential regulator for hepcidin, which possibly acts by triggering FXR and the BMP6/ALK3-SMAD signaling pathway. Furthermore, 40 C57/BL6 mice were treated with 100 mg/kg/d, 200 mg/kg/d, and 300 mg/kg/d GCDCA to investigate its effect on hepcidin in vivo. The serum level of hepcidin increased in mice treated with 200 mg/kg/d and 300 mg/kg/d GCDCA, while hemoglobin and serum iron levels decreased. Similarly, the FXR-mediated SMAD signaling pathway was also responsible for activating hepcidin in liver. Overall, it was concluded that GCDCA could induce the expression of hepcidin and reduce serum iron level, in which FXR activation-related SMAD signaling was the main target for GCDCA. Thus, abnormal GCDCA level indicates a potential risk of iron homeostasis imbalance.

Fibroblast growth factor 19 (FGF19) acts as a novel factor in the regulation of skeletal muscle mass in animal models by regulating energy expenditure. People with obesity have a lower content of FGF19 and lose muscle mass easily. However, as the main energy metabolism organelles, the involvement of mitochondria in the protective effect of FGF19 is still unknown. In this study, the protective effects of FGF19 on palmitate-induced damages in differentiated mouse myoblast cells (C2C12) were studied, including myotube morphology, mitochondrial function and the regulation of pathways and genes. Excessive palmitate resulted in myotube atrophy and activation of the mitochondria-mediated apoptosis pathway in C2C12 cells. Palmitate also inhibited glucose uptake and induced insulin resistance. FGF19 addition during the differentiation of C2C12 cells, returned the palmitate-induced mitochondrial respiration and apoptosis to the control levels and improved the insulin sensitivity. The palmitate-induced upregulation of genes involved in β-oxidation (PPARβ/δ, PPARγ, UCP-1, MCAD) and the downregulation of genes related to myotube atrophy (PPARα, PGC-1α and PGC-1β) were also alleviated by FGF19. In summary, FGF19 prevented excessive palmitate-induced dysfunction of C2C12 cells by protecting mitochondrial overload and apoptosis and maintaining normal insulin signaling.

BACKGROUND Ectopic fat accumulation in skeletal muscle results in dysfunction and atrophy, but the underlying molecular mechanisms remain unclear. OBJECTIVE The aim of this study was to investigate the effects of a high-fat diet (HFD) in modulating the structure and energy metabolism of skeletal muscle and the underlying mechanisms in mice. METHODS Four-week-old male C57BL/6 J mice (n = 30) were allowed 1 wk for acclimatization. After 6 mice with low body weight were removed from the study, the remaining 24 mice were fed with a normal-fat diet (NFD; 10% energy from fat, n = 12) or an HFD (60% energy from fat, n = 12) for 24 wk. At the end of the experiment, serum glucose and lipid concentrations were measured, and skeletal muscle was collected for atrophy analysis, inflammation measurements, and phosphoproteomic analysis. RESULTS Compared with the NFD, the HFD increased (P

Age-associated loss of skeletal muscle mass and function is one of the main causes of the loss of independence and physical incapacitation in the geriatric population. This study used the D-galactose-induced C2C12 myoblast aging model to explore whether nobiletin (Nob) could delay skeletal muscle aging and determine the associated mechanism. The results showed that Nob intervention improved mitochondrial function, increased ATP production, reduced reactive oxygen species (ROS) production, inhibited inflammation, and prevented apoptosis as well as aging. In addition, Nob improved autophagy function, removed misfolded proteins and damaged organelles, cleared ROS, reduced mitochondrial damage, and improved skeletal muscle atrophy. Moreover, our results illustrated that Nob can not only enhance mitochondrial function, but can also enhance autophagy function and the protein synthesis pathway to inhibit skeletal muscle atrophy. Therefore, Nob may be a potential candidate for the prevention and treatment of age-related muscle decline.

Detecting pesticide residues in human serum is a challenging process due to trace-level chronic exposure. Several methods using magnetic adsorbents have been developed for analyzing pesticide residue levels in human serum, but it is still difficult to achieve lower quantitative levels, and the adsorption mechanism for extracting pesticides is unclear. Herein, we propose a feasibility concept of using C

Chlorpyrifos is a commonly-used pesticide which was reported to interfere with hormone signaling and metabolism, however, little is known about its effect on gut microbiota. In this study, adult male rats fed a normal (NF) or high fat (HF) diet were exposed to 0.3 or 3.0 mg chlorpyrifos/kg bodyweight/day or vehicle alone for 9 weeks. Effects on bodyweight, serum levels of glucose, lipid, cytokines, and gut microbiome community structure were measured. The effects of chlorpyrifos on metabolism were dose- and diet-dependent, with NF-fed rats administered the low dose showing the largest metabolic changes. NF-fed rats exposed to chlorpyrifos exhibited a pro-obesity phenotype compared with their controls, whereas there was no difference in pro-obesity phenotype between HF-fed groups. Chlorpyrifos exposure significantly reduced serum insulin, C-peptide, and amylin concentrations in NF- and HF-fed rats, leaving serum glucose and lipid profiles unaffected. Chlorpyrifos exposure also significantly altered gut microbiota composition, including the abundance of opportunistic pathogens, short chain fatty acid-producing bacteria and other bacteria previously associated with obese and diabetic phenotypes. The abundance of bacteria associated with neurotoxicity and islet injury was also significantly increased by chlorpyrifos. Our results suggest risk assessments for chlorpyrifos exposure should consider other effects in addition to neurotoxicity.

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In order to colonize the human gastrointestinal tract and exert their beneficial effects, bifidobacteria must effectively cope with the toxic bile salts in the intestine, but the molecular mechanism underlying bile tolerance is poorly understood. In this study, heterologous expression of a MarR family transcriptional regulator BmrR significantly reduced ox-bile resistance ofLactococcus lactisNZ9000, suggesting that it might play a role in bile stress response.In silicoanalysis combined with RT-PCR assay demonstrated thatbmrRwas co-transcribed withbmrAandbmrB,which encoded multidrug resistance (MDR) ABC transporters. Promoter prediction and EMSA assay revealed that BmrR could autoregulate thebmrRABoperon by binding tobmrbox (ATTGTTG-6nt-CAACAAT) in the promoter region. Moreover, heterologous expression ofbmrAandbmrBinL. lactisshowed 20.77-fold higher tolerance to 0.10% ox-bile compared to wild type strain. In addition, ox-bile could disrupt the DNA binding activity of BmrR as a ligand. Taken together, our findings indicate thatbmrRABoperon is autoregulated by transcriptional regulator BmrR and ox-bile serves as an inducer to activate the bile efflux transporter BmrAB in response to bile stress inB. longumBBMN68.ImportanceBifidobacteria are natural inhabitants of the human intestinal tract. Some bifidobacterial strains are used as probiotics in fermented dairy production because of their health-promoting effects. Following consumption, bifidobacteria finally colonize the lower intestinal tract where the concentration of bile salts remains nearly 0.05% to 2.0%. Bile salts as detergent-like antimicrobial compounds can cause disruption of the cellular membrane, protein misfolding and DNA damage. Therefore, tolerance to physiological bile stress is indeed essential for bifidobacteria to survive and exert the probiotic effects in gastrointestinal tract. InB. longumBBMN68, the MarR-type regulator BmrR was involved in bile stress response by auto-regulatingbmrRABoperon and ox-bile as an inducer could increase the expression of BmrAB transporter to enhance the bile tolerance of BBMN68.This is the first report about functional analysis ofbmrRABoperon in bile stress response, which will provide new insight into bile tolerance mechanisms inBifidobacteriumand other bacteria.

An efficient electrochemical protocol for the synthesis of α-amino ketones via the oxidative cross-dehydrogenative coupling of ketones and secondary amines has been developed. The electrochemistry performs in a simple undivided cell using NH4I as a redox catalyst and a cheap graphite plate as electrodes under constant current conditions. Gram-scale reaction demonstrates the practicality of the protocol. The reaction is proposed to procced through an initial α-iodination of ketone, followed by a nucleophilic substitution of amines.

Efficient electrochemical amino-oxygenation of styrenes has been developed for the synthesis of 3-methoxyindolines and 3-ethoxyindoline, using a simple beaker-type undivided cell with n-Bu4NI serving as a redox catalyst under constant current electrolysis (CCE) conditions. The chemistry proceeds in a paired electrolysis mode, avoiding the utilization of external oxidants and bases and therefore represents an environmentally benign means. The process also works in the absence of an additional conducting salt. Gram-scale reaction further demonstrates the practicability of the protocol. Proton NMR spectroscopy was used to demonstrate that the amino-oxygenation of N-(2-vinylphenyl)sulfonamides likely involves the initial iodoamination of the alkene, followed by nucleophilic substitution of the methoxide/ethoxide generated at the cathode.

The synergistic antioxidant mechanism of chlorogenic acids (CQAs) was studied in this paper through cyclic voltammograms (CV), oil-water partition coefficient (P), FT-IR, XRD and circular dichroism (CD). The antioxidant capability of CQAs isomers and their mixture was determined by using ABTS free radical quenching ability assay. The results showed that the bigger the antioxidant activity disparity between the CQAs molecules was, the higher the content of high antioxidant activity CQAs was, the better the synergistic effect of the CQAs combination mixture became; The oxidation potential (Epa) of CQAs combination mixture kept constant in the synergistic experiments, which indicted the oxidative coupling interaction don’t exist between the CQAs; The charge transferred (Q) and antioxidant activity exhibited high correlation (0.92); the practical Q was higher than the theoretical Q in the synergistic process and this confirmed that the CQAs (dicaffeoylquinic acids) regeneration of high antioxidant activity happened; the CQAs mixture with the absolute difference value of oil-water partition coefficient of 0.13 gave the good interface effect and high synergistic degree; the interaction and the regular arrangement between the CQAs combination were not discovered through FT-IR, XRD and CD. Therefore, the regeneration mechanism of CQAs molecules and the interface effect of reaction system were the main cause of the phenomenon of the synergistic antioxidant of CQAs.

The aim of this study was to investigate the antioxidant potential of bovine casein glycomacropeptide (GMP) and its hydrolysate, as well as to determine effects of GMP and its hydrolysate on hydrogen peroxide (H2O2)-induced oxidative stress in RAW 264.7 macrophages. In comparison with native GMP, GMP hydrolysate obtained with papain for 1 h hydrolysis (GHP) exerted higher free radical-scavenging capacity, ferrous ion (Fe2+)-chelating ability, and ferric reducing (FRAP) activity. GHP significantly blocked H2O2-induced intracellular reactive oxygen species (ROS) generation as well as cell death, and the cytoprotective effects of GHP were partially reversed by co-treatment with zinc(II)-protoporphyrin IX (ZnPPIX), a specific inhibitor of HO-1. GHP induced nuclear translocation of the nuclear factor-erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expression in RAW 264.7 macrophages. The chemical antioxidant, N-acetyl cysteine (NAC), significantly reduced GHP-induced HO-1 expression and Nrf2 activation by blocking intracellular ROS production. Additionally, pretreatment with GHP enhanced cellular antioxidant enzymes activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) in H2O2-damaged cells. The antioxidant activity of GHP may be attributed to its amino acid profiles. Compared with native GMP, GHP had higher contents of alanine, glycine, glutamic acid, aspartic acid and branched chain amino acids (BCAAs, leucine, isoleucine and valine). BCAAs-enriched GHP may possess a potential to ameliorate oxidative stress-related diseases.

Using cryo scanning electron microscopy, smaller casein micelles (20–60 nm) were found adsorbed onto the native milk fat globule membrane (MFGM). The casein existing as structural constituents of the native MFGM might participate in controlling the stability of fat globules. Whey protein at the surface of globules was also observed.

siRNA is promising in anti-tumor therapy. The main challenge is lack of tumor-specific intracellular delivery. In this study, a 6 amino acids peptide (A1) with high affinity for vascular endothelial growth factor receptor-1 (VEGFR1) was conjugated with a cell penetrating peptide (CPP) TAT to form a tumor-selective CPP. To evaluate the tumor-targeted penetrate property of TAT-A1, the uptake of TAT-A1 was measured by flow cytometry. The selectivity in vitro was tested in co-cultured tumor cells and normal cells by laser confocal microscope. The internalization efficiency of TAT-A1 was significantly higher than that of TAT (p

An efficient electrochemical protocol for the synthesis of α-amino ketones via the oxidative cross-dehydrogenative coupling of ketones and secondary amines has been developed. The electrochemistry performs in a simple undivided cell using NH

Efficient electrochemical amino-oxygenation of styrenes has been developed for the synthesis of 3-methoxyindolines and 3-ethoxyindoline, using a simple beaker-type undivided cell with n-Bu4NI serving as a redox catalyst under constant current electrolysis (CCE) conditions. The chemistry proceeds in a paired electrolysis mode, avoiding the utilization of external oxidants and bases and therefore represents an environmentally benign means. The process also works in the absence of an additional conducting salt. Gram-scale reaction further demonstrates the practicability of the protocol. Proton NMR spectroscopy was used to demonstrate that the amino-oxygenation of N-(2-vinylphenyl)sulfonamides likely involves the initial iodoamination of the alkene, followed by nucleophilic substitution of the methoxide/ethoxide generated at the cathode.

The biological function of α-lactalbumin (α-LA) depends on its conformation. α-LA can adopt a stable intermediate state induced by heating or pH change. This intermediate state associates with oleic acid (OA) to form an anti-tumor complex. The effect of temperature on the formation the complex has been studied, whereas the effect of pH on complex formation remains unresolved. The effect of pH on tryptophan residues, hydrophobic clusters and secondary structure of Ca(2+)-depleted bovine α-LA (BLA) was studied by fluorescence spectroscopy and circular dichroism. BLA was found to adopt a more flexible conformation between pH 7.0 and 9.0 with buried hydrophobic clusters. The binding ability of α-LA towards OA and the anti-tumor activity of the corresponding complex were also studied. BLA was found to bind more OA over the pH range of 7.0-9.0 and the corresponding complexes showed a higher anti-tumor activity than those complexes formed under acidic conditions. Our study indicates that alkaline pH aided the formation of the complex as well as its anti-tumor activity. We also propose a possible characteristic structure that facilitates binding of OA.

The crude polysaccharide from the stem of Dendrobium officinale (DOP) was obtained by water extraction and ethanol precipitation. Two fractions of DOP, DOP-1 and DOP-2, were fractioned by DEAE cellulose and Sephacryl S-400 gel filtration column chromatography. Their molecular weights and monosaccharide compositions were studied. The immunomodulatory activity of DOP, DOP-1 and DOP-2 was evaluated with in vitro cell models. The results showed that the 533.7 kDa DOP-1 and 159.5 kDa DOP-2 were mainly composed of mannose and glucose. Both DOP and its purified fractions significantly (P

Because of the health problems associated with trans fatty acids (TFAs) in hydrogenated oil, the objective of this research was to accelerate crystallization of the trans-free unhydrogenated palm oil (UPO) as a hydrogenated palm oil (HPO) substitute. Crystallization thermograms of UPO blended with icing sugar (1:1.5 mass ratio) from different initial heating temperatures were measured by differential scanning calorimetry (DSC), to study its effects on crystallization rate. DSC thermograms of UPO and HPO cooled from two melt states (the complete melting state 80 °C and the incomplete state 40 °C) were also compared. Crystallization rates from temperatures above the melting point (m.p.) were faster than those below the top limit of the m.p. The reason may be that a higher initial heating temperature induced a completely melted state and thus a larger driving force toward the solid phase. Raising the processing temperature to 80 °C, UPO may have a crystallization rate the same as, if not faster than, HPO. This study provides a new way to accelerate the crystallization of the trans-free UPO, making HPO a realistic substitute in the food industry.

Lactoferrin (LF) is reported to stimulate osteoblast proliferation and inhibit osteoclast activity in bone cell culture. However, the effect of oral LF on bone in osteoporosis needs to be explored. Three-month-old female Sprague-Dawley rats (n = 70) were assigned to the following groups: sham-operated, ovariectomized (OVX) untreated, OVX + bovine serum albumin (BSA; 85 mg/kg body weight), OVX + LF (0.85 mg/kg, 8.5 mg/kg, and 85 mg/kg body weight), and OVX + 17beta-estradiol (E(2); 10 microg/kg body weight). After 3 mo of treatment, E(2) completely prevented the OVX-induced bone loss. OVX rats treated with LF were protected against the OVX-induced reduction of bone volume, trabecular number, and thickness, and the elevation of trabecular separation was prevented. LF also increased bone mineral density and increased the parameters of mechanical strength at 8.5- and 85-mg/kg doses. Greater bone formation and reduced bone resorption, as assessed by biochemical markers of bone remodeling, occurred in rats administered LF. LF at 8.5- and 85-mg/kg concentrations caused a significant decrease in serum calcium, but this reduction did not occur in rats fed 0.85 mg/kg LF. In addition, serum tumor necrosis factor-alpha and interleukin-6 production were suppressed and serum calcitonin was elevated significantly in LF-fed rats at all 3 doses. These findings indicated that oral LF not only preserved bone mass but also improved bone microarchitecture. The absorption of LF peptides and their effects on bone cells could to some extent account for the osteogenic function of oral LF.

Yak milk is a type of milk that people are less familiar with due to its remote geographical location, the particular geographical environment and climatic conditions in Tibet, which may have significant effects on composition, microbiota and fermentation outcome. To investigate the chemical composition and microbiota of fresh and fermented yak milk, and to isolate and characterize the predominant microorganisms in the fermented milk, yak milk (24 fresh and 30 fermented milk samples) was collected from four areas of different altitudes in Tibet, and their microbiological profile and chemical composition were investigated. Yak milk had a higher fat, crude protein, lactose and dry matter content than cow milk. The fermented yak milk showed a great diversity in fat and dry matter levels due to the different ways of processing in different localities, and lower pH and higher lactic acid content compared with commercial cow milk yogurt. Fermented yak milk had a better sanitary quality than fresh yak milk. Three species of lactobacilli (Lactobacillus fermentum, Lactobacillus helveticus and Lactobacillus curvatus) and five species of yeast (Saccharomyces cerevisiae, Candida kefyr, Candida lambica, Candida famata and Candida holmii) were identified phenotypically and encountered as predominant fermentation microbiota. The predominant lactic species in fermented milk was L. fermentum.

The structure changes of α-lactalbumin after binding oleic acid and linoleic acid, including hydrophobic amino acids, hydrophobic regions, tertiary structure, secondary structure, was studied by intrinsic fluorescence, ANS-binding intrinsic fluorescence and circular dichroism spectrum, respectively. The anti-tumor activity of the lactalbumin-oleic acid complex and lactalbumin-linoleic acid complex was measured using the methylene blue method. It can be seen from the fluorescence spectra that a significant red-shift from 331.07 to 337.67 nm and 337.60 nm of α-lactalbumin occurred after binding of oleic acid and linoleic acid, respectively. Together with the ANS-binding spectra, which exhibited a blue-shift (from 516.20 to 514.10 nm and 508.50 nm, respectively) with an increased fluorescence intensity, it can be indicated that binding of oleic acid and linoleic acid lead to the exposure of hydrophobic amino acids and hydrophobic regions. Results of circular dichroism spectra indicated the partial loss of the tertiary structure, and an decrease of β-turn and random coil, which turn to the β-sheet structure. Furthermore, the anti- tumor activity of the two complexes was verified on the three types of tumor cells. This study laid a theoretical basis for the development of anti-tumor drugs.

Asia differs substantially among and within its regions populated by diverse ethnic groups, which maintain their own respective cultures and dietary habits. To address the diversity in their gut microbiota, we characterized the bacterial community in fecal samples obtained from 303 school-age children living in urban or rural regions in five countries spanning temperate and tropical areas of Asia. The microbiota profiled for the 303 subjects were classified into two enterotype-like clusters, each driven by Prevotella (P-type) or Bifidobacterium/Bacteroides (BB-type), respectively. Majority in China, Japan and Taiwan harbored BB-type, whereas those from Indonesia and Khon Kaen in Thailand mainly harbored P-type. The P-type microbiota was characterized by a more conserved bacterial community sharing a greater number of type-specific phylotypes. Predictive metagenomics suggests higher and lower activity of carbohydrate digestion and bile acid biosynthesis, respectively, in P-type subjects, reflecting their high intake of diets rich in resistant starch. Random-forest analysis classified their fecal species community as mirroring location of resident country, suggesting eco-geographical factors shaping gut microbiota. In particular, children living in Japan harbored a less diversified microbiota with high abundance of Bifidobacterium and less number of potentially pathogenic bacteria, which may reflect their living environment and unique diet.

The effects of calcium ion on the structural properties of casein micelles in the course of heat treatment were synthetically examined by non-structure-invasive spectrometry. The hydrophobicity, reflected by extrinsic fluorescence (ANS fluorescence), was positively correlated with the concentration of the calcium ion, within the range of 0 to 12 mmol x L(-1). Meanwhile, the turbidity and stability of casein micelles also increased with the growth of calcium concentrations. However, opposite results were observed for hydrodynamic diameter and polydispersity index. Compared with the calcium ion, the calcium-chelator (citrate) has an opposite effect on the structural characteristics of casein micelles. Within the calcium concentrations range of 0 to 12 mmol x L(-1), the hydrophobicity, stability and turbidity were negatively correlated with the concentration of the calcium ion, nevertheless, opposite results were observed for hydrodynamic diameter and polydispersity index. All the results indicate that the calcium ion could be used to modify the structures of casein micelles during heat heatment.

Modes and influencing factors of bovine serum albumin (BSA) and quercetin (QUE) interaction will help us understand the interaction mechanisms and functional changes of bioactive small molecules and biomacromolecules. The fluorescence spectroscopy, UV-Vis spectroscopy, synchronous fluorescence spectroscopy, DPPH and ABTS radical scavenging assays were used to investigate the characteristics and antioxidant activity of BSA and QUE interaction in three solvent systems (deionized water, dH2O; dimethyl sulfoxide, DMSO and ethanol, EtOH). The results revealed that QUE had a great ability to quench BSA's fluorescence in both static and dynamic modes, and that hydrophobic interaction played a dominant role in BSA and QUE interaction in three solvent systems. The binding constant values and binding site numbers between BSA and QUE were in the order of dH2ODMSOEtOH. The binding distances were in the order of EtOHDMSOdH2O. On the basis of the binding distance, the binding forces were in the order of dH2ODMSOEtOH. The synchronous fluorescence spectra demonstrated that QUE interacted with both tyrosine and tryptophan residues of BSA in three solvent systems. Moreover, the DPPH radical scavenging rates of both QUE and BSA-QUE were 30%. While, the ABTS radical scavenging rate of QUE was significantly decreased from 80% to 70% when bound to BSA. No significant difference in antioxidant activity between QUE and BSA-QUE was observed in three solvent systems.

The effects of heat treatment (heating temperature and pH) on the structures and emulsifying properties of caseins were systematically studied by spectroscopy. Heat treatment from 60 to 100 degrees C resulted in an increase in their fluorescence intensity, hydrodynamic diameter, turbidity and emulsifying activity index, but decreased the size polydispersity of caseins. In the pH range of 5.5 to 7.0, the fluorescence intensity, hydrodynamic diameter, turbidity and emulsifying properties decreased with increased heating pH, but the size polydispersity of caseins increased with increased pH. The relationship between the surface fluorescence intensity and emulsifying activity was also investigated, revealing a correlation coefficient of 0.90. These results suggested that heat treatment could be used to modify the structures and emulsifying properties of caseins by appropriately selecting heating conditions.

In this paper, two statistical methods were applied to optimize medium components to improve the production of the milk-clotting enzyme by Bacillus amyloliquefaciens D4. First, wheat bran juice, skim milk powder, and Na2HPO4 were shown to have significant effects on D4 enzyme production using the Plackett?Burman experimental design. Subsequently, an optimal medium was obtained using the Box?Behnken method, which consisted of 3.31 g/l of skim milk powder, 5.0 g/l of sucrose, 0.1 g/l of FeSO4?7H2O, 0.1 g/l of MgSO4?7H2O, 0.1 g/l of MnSO4?2H2O, 0.1 g/l of ZnSO4?7H2O, 1.52 g/l of Na2HPO4, and 172.45 g/l of wheat bran juice. With this optimal medium, the milk-clotting enzyme production was remarkably enhanced. The milk-clotting enzyme activity reached 3,326.7 SU/ml after incubation of 48 h, which was 1.76-fold higher than that of the basic medium, showing that the Plackett?Burman design and Box?Behnken response surface method are effective to optimize medium components, and B. amyloliquefaciens D4 possessed a high rennet-producing capacity in the optimal medium.

The interaction between caffeic acid and milk protein (alpha-casein, beta-casein, kappa-casein, alpha-lactalbumin, beta-lactoglobulin) were studied in this work. The binding constant K(A), binding force, binding distance r(0) and transfer efficiency E were evaluated by UV-absorption and fluorescence spectroscopy. The antioxidant capacity of the combination was determined using both 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and ferric reducing antioxidant power (FRAP) assay. The results showed that the interaction between milk protein and caffeic acid resulted in the endogenous fluorescence quenching of milk protein, which belongs to a static quenching mechanism. The negative sign of free energy meant that the interaction process was spontaneous. The strength between caffeic acid and alpha-casein was electrostatic attraction (deltaH0, deltaS0), and that between beta-casein and alpha-Lactalbumin was hydrogen bonding (deltaH0, deltaS0). In addition, the strength of caffeic acid interacting with kappa-casein and beta-lactoglobulin was hydrophobic interaction (deltaH0, deltaS0). The binding distance (r(0)7 nm) proved that caffeic acid lead to a static quenching mechanism of milk protein. The antioxidant capacity of caffeic acid was inhibited by milk protein to different degrees.

The interactions between three proteins (BSA, lysozyme and myoglobin) and three flavonoids (quercetin, kaempferol and rutin) were analyzed, using three-dimensional fluorescence spectrometry in combination with UV-Vis spectrometry and Fourier transform infrared (FTIR) spectroscopy. The stabilities of unbound flavonoids and protein-bound flavonoids were compared. The correlation between the interaction and stability was analyzed. The results showed that the hydrophobic interaction was the main binding code in all proteins and flavonoids systems. However, the hydrogen bond has been involved merely in the BSA system. The stability of all three flavonoids (quercetin, kaempferol and rutin) was improved by BSA. There was a great correlation between the hydrogen bonding and the stability of the flavonoids in the presence of BSA. It suggested that the protection of BSA on the flavonoids was due to the intermolecular hydrogen bonding between BSA and flavonoid, and the stronger hydrogen bonding resulted in more protection.

In this study, the tertiary, secondary structures and disulfide bond changes of bovine lactoferrin (bLF) under 6 differents physico-chemical treatments were investigated by fluorescence, circular dichroism(CD) and UV-Vis absorption. A red shift from 333 to 354 nm in the fluorescence emission maximum (lambda(max)) was observed in the bLF treated by 6 mol x L(-1) GdnHCl, 8 mol x L(-1) Urea and 50 mmol x L(-1) DTT simultaneously, meanwhile a large number of exposed hydrophobic groups were detected. However, there was no marked shift in lambda(max) of bLF treated by heating (100 degrees C, 5 min), Ultrosonic(450 W, 5 s, 6 pulses) or beta-ME (1%), of which fluorescence intensity decreased significantly compared with the untreated bLF. The results indicated that the mechanism of changes in tertiary structure of the former three methods were different from the latter three. The detection by CD showed that the alpha- helix structure vanished completely in the bLF treated by GdnHCl. However, there was no remarkable change in the secondary structure of the bLF treated by the other five methods. In addition, UV-Vis absorption suggested that disulfide bond was seriously destructed in the bLF treated by DTT and Ultrosonict, but GdnHCl, beta-ME and heating induced a little damage merely. This study is instructive and meaningful to the further research on relationship between structure and activity of bLF.

Fourier transform infrared spectroscopy (FTIR) and circular dichroism (CD) were used to investigate the conformational changes of heated whey protein (WP) and the corresponding changes in the hydrolysates immunoreactivity were determined by competitive enzyme-linked immunosorbent assay (ELISA). Results showed that the contents of alpha- helix and beta-sheet of WP did not decrease much under mild heating conditions and the antigenicity was relatively high; when the heating intensity increased (70 degrees for 25 min or 75 degrees C for 20 min), the content of alpha- helix and beta-sheet decreased to the minimum, so was the antigenicity; However, when the WP was heated at even higher temperature and for a longer time, the beta-sheet associated with protein aggregation begun to increase and the antigenicity increased correspondingly. It was concluded that the conformations of heated WP and the antigenicity of its hydrolysates are related and the optimum structure for decreasing the hydrolysates antigeniity is the least content of alpha-helix and beta-sheet. Establishing the relationship between the WP secondary structure and WP hydrolysates antigenicity is significant to supply the reference for antigenicity reduction by enzymolysis.

Spray drying is an important processing of producing modificatied yolk powder (MEYP). To investigate the correlation between the secondary structure and emulsifying property of MEYP made at different spray-drying-temperatures, Fourier transform infrared spectroscopy (FTIR) was applied in the present study. The result indicated that emulsifiability and the percentage of alpha-helix were both significantly increased firstly and then remarkably decreased with rising of spray-drying-temperature, and the emulsifying property of MEYP was relative to the percentage of alpha-helix. After heat-treating, the percentage of alpha-helix was significantly decreased and the percentage of p-sheet was remarkably increased, however, the total percentage of the two structures was maintained. The stable total percentage of alpha-helix and beta-sheet would be a good explanation for the great heat stability of emulsion presented in the MEYP made at different spray-drying temperature.

Proteolysis is one of the most important biochemical reactions during cheese ripening. Studies on the secondary structure of proteins during ripening would be helpful for characterizing protein changes for assessing cheese quality. Fourier transform infrared spectroscopy (FTIR), with self-deconvolution, second derivative analysis and band curve-fitting, was used to characterize the secondary structure of proteins in Cheddar cheese during ripening. The spectra of the amide I region showed great similarity, while the relative contents of the secondary structures underwent a series of changes. As ripening progressed, the alpha-helix content decreased and the beta-sheet content increased. This structural shift was attributed to the strengthening of hydrogen bonds that resulted from hydrolysis of caseins. In summary, FTIR could provide the basis for rapid characterization of cheese that is undergoing ripening.

Interaction of lactoferrin and its peptides LfcinB4-14 and LfampinB with dipalmitoylglycero-phosphocholine (DPPC) and dipalmitoylglycero-phosphoglycerol (DPPG) liposomes were studied by means of Raman spectroscopy. In our study, conformational changes in the phospholipid molecules were investigated by measuring the intensities of 2 847 and 2 882 cm(-1) Raman bands which are assigned to acyl chains' symmetric and asymmetric C-H stretching vibrations. The addition of lactoferrin and its peptides LfcinB4-14 and LfampinB caused a decrease in the 2 882 cm(-1) intensity of DPPG liposomes, thus the order parameter for the lateral interactions between chains S(lat) decreased from 0.19 to 0.17, 0.14 and 0.12 respectively. On the contrary, the intensities at 2 847 and 2 882 cm(-1) of DPPC liposomes were poorly affected by lactoferrin and its peptides. The results show that lactoferrin and its peptides present a stronger effect on the molecular structure and order degree of anionic lipid DPPG than that of zwitterionic lipid DPPC. This suggests that lactoferrin, LfcinB4-14 and LfampinB can interact and combine with the negatively charged DPPG liposomes by electrostatic interaction and perform its antibacterial activity. Besides, LfcinB4-14 and LfampinB can affect the lipid more strongly than lactoferrin.

As a highly efficient, convenient and nondestructive detection method, near-infrared spectroscopy (NIRS) is appropriate for the analysis of milk and dairy products. The present review discusses the principle of the near-infrared spectroscopy analysis technology and the evaluation standard criteria of milk and dairy products, and also reviews the hardware device technology and the data processing technique for the analysis of milk and dairy products in order to promote the application of near-infrared spectroscopy analysis technology in milk and dairy products quality control in China.

The microstructure of the pectin/whey protein isolate mixtures under incompatible conditions was investigated using dynamic light scattering spectroscopy, transmission electron microscopy and shear-viscosity model. Under the condition of 90 degrees C and pH 7.4, the presence of negatively charged pectin could induce depletion aggregation in a 5% protein solution, and promote phase separation; precisely, when the mass ratio of pectin/whey protein isolate was lower than 0.08, the hydrodynamic size of the aggregates was less than 300 nm, and the system showed Newtonian properties; when the mass ratio was higher than 0.08, the viscosity of the solution increased rapidly, the shear thinning properties became obvious and the size of the aggregates was close to 700 nm.

The particles conformation of the sericin protein extracted from silkworm Bombyx mori was studied under the conditions of different pH and salt concentrations by infrared spectroscopy (IR), dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. The IR spectrum of sericin protein arises predominantly from C=O stretching vibration around the amide I region of 1 700-1 600 cm(-1). A strong trend of aggregation of the protein could be observed under specified experimental conditions. The apparent isoelectric point of the sericin protein was about 3.7. The DLS method was used to investigate the effects of pH and NaCl on the size distribution, where a large polydispersity of the system could be observed. Compared to pH 4 or high NaCl concentration, at pH 3, 8 or low NaCl concentration the sericin aggregation shows a relatively smaller size but larger polydispersity. TEM was used to investigate the microstructure of the aggregated sericin protein, where a loose and pine-like branched form could be observed at pH 3 or 8; however, a relatively compact structure was observed near pH 4 or at high salt concentration At pH 4 the spherical monomer size can be calculated at around (60 +/- 6) nm (n = 10) by TEM measurement. These phenomena could be explained by the effects of the electrostatic repulsion, hydrogen bonding and Van der Waals attractive force, which provide a basic theory for the application of sericin as biomaterial.

The objective of the present paper was to evaluate the X-ray three-dimensional micro-computed tomography (X-microCT) method applied in assessing the trabecular structure in ovariectomized rats. Three-month-old female Sprague-Dawley rats (n = 30) were ovariectomized (OVX) or sham-operated (SHAM). OVX rats were treated with vehicle, or 17beta-estradiol (E2, positive control) for 3 months. For the conventional histomorphometric analysis, undecalcified sections were prepared and stained with the Li Chunhong technique to obtain high-contrast two-dimensional images. Prior to the histologic sectioning the samples were measured by X-microCT, providing a 14 microm resolution. The morphometric parameters computed by both methods in two or three dimensions, respectively, were bone volume over total volume (BV/TV), trabecular thickness (Tb. Th), trabecular number (Tb. N) and trabecular separation (Tb. Sp). Results showed that there were significant differences in the trabecular structure among three groups. In the OVX control group, the platelike structure was mostly resolved into a rodlike structure, with lots of the connecting rods missing. Whereas in OVX+E2 groups, this loss of trabecular bone mass and connectivity was prevented, with the results being nearly the same as those in the SHAM group. It was shown that highly significant correlations between conventional histology and X-microCT for BV/TV, Tb. Th, Tb. N and Tb. Sp were 0.984, 0.960, 0.995, and 0.988 in tibia, and 0.938, 0.968, 0.877 and 0.951 in lumbar. The high correlations between conventional histomorphometric and micro-tomographic analysis are very promising for the use of micro-tomographic imaging. X-microCT is a nondestructive, fast, and very precise procedure that allows the measurement of cancellous tissue in unprocessed biopsies or small bones, as well as a fully automatic determination of three-dimensional morphometric indices.

Metabolism is essential for the survival of cells with the production of free radicals. There is increasing evidence for the involvement of such species in a variety of normal in vivo regulatory systems. When an excess of free radicals is formed, they cause destructive and lethal cellular effects by oxidizing membrane lipids, cellular proteins, DNA and enzymes. In addition, it has been recognized that oxidative stress plays a significant role in a number of diseases. For example, many studies have shown increased oxidative damage to all the major classes of biomolecules in the brains of Alzheimer's patients. Furthermore, cancer is probably a consequence of oxidative DNA damage. Therefore, the determination methods of free radical are very important and necessary. The development of determination techniques of hydroxyl and superoxide radicals was reviewed with 62 references in the present paper, the techniques of determination mainly include spectrophotometry, fluorophotometry, chemiluminescence, and electron spin resonance, and their advantages and disadvantages were evaluated.

Donkey milk has aroused more attention in recent years since its nutrition composition shows a higher similarity to human milk than others. Due to the composition difference between cow milk and donkey milk, the present models available for cow milk analysis could not be applied to donkey milk without modifications. A rapid and reliable analysis method is required to measure the nutrition composition of donkey milk. Near infrared spectroscopy is a newly developed method in food industry, but no literature report was found regarding to its application in the analysis of donkey milk. Protein, fat, ash contents and energy value are the major nutrition factors of milk. In the present paper, these factors of donkey milk were investigated by Fourier transform near-infrared (FT-NIR) spectroscopy. The ranges of protein, fat and ash contents, and energy value in donkey milk samples were 1.15%-2.54%, 0.34%-2.67%, 0.28%-0.57% and 355.87-565.17 cal x kg(-1), respectively. The IR spectra ranged f from 3 899.6 to 12 493.4 cm(-1), with a 1 cm(-1) scanning interval. When the principal least square (PLS) regression algorithm is used for spectral regions information extraction, the additional constraint makes the principal components of matrix X to be related with the components of Y which is to be analyzed. Various spectral regions and data pretreatment methods were selected for principal least square (PLS) regression model development. A comparison of the whole and optimized spectral region NIR indicated that the models of selecting optimum spectral region were better than those of the whole spectral region. It was shown that the protein, fat and ash contents, and energy value in donkey milk obtained by chemical methods were well correlated to the respective values predicted by the NIR spectroscopy quantitative analysis model (alpha = 0.05). The RMSEP values were 0.18, 0.117, 0.040 6 and 23.5 respectively, indicating that these predicted values were reliable. These results suggested that FT-NIR spectroscopy could be used for the rapid detection of the composition of donkey milk by establishing NIR spectroscopy quantitative analysis models. Selecting an optimum spectral region and establishing a special NIR analysis model accordingly are key steps during the data pretreatment. The models of the optimum spectral region were better than the models of the whole spectral region. When irrelevant information was included in the models, it would interfere with the analysis and give less reliable results. Therefore, the selection of a right spectra region plays an important role in the set-up of quantitative analysis models. The accuracy and reliability of the standard data used in model settings are also critical to the final results. In order to improve the reliability and accuracy of the NIR methods, a wide range of component contents and more accurate standard data are definitely required.

Antioxidant and antimicrobial properties of 10 Chinese medicinal herb extracts were evaluated by dipping raw sheep meat in extracts, packaging the samples in polyethylene, and refrigerating them at 4 degrees C. The optimum concentrations of Codonopsis pilosula, Platycodon grandiflorum, Artemisia capillaris, Cinnamomum cassia, Rheum palmatum, Ziziphus jujuba, Gardenia jasminoides, Santalum album, Angelica sinensis, and Bletilla striata were 0.10, 0.10, 0.25, 0.10, 0.25, 0.25, 0.25, 0.10, 0.25, and 0.25%, respectively. Analysis revealed that test ingredients were more effective in reducing lipid oxidation and microbial counts in raw sheep meat. Correlation analysis revealed a significant negative linear relationship between the inhibition of hydroxyl and lipid oxidation, and inhibition of hydroxyl was the main factor affecting lipid oxidation. A. capillaris (0.25%), C. pilosula (0.10%), and P. grandiflorum (0.10%) were identified as the most effective antioxidants. S. album (0.10%), A. capillaris (0.10%), and C. cassia (0.10%) were the most effective antimicrobials. A. capillaris (0.25%), C. pilosula (0.10%), and P. grandiflorum (0.10%) increased meat redness significantly (P0.05) when compared with the control samples on days 0, 3, 5, 7, 9, 10, and 11. The pH values of sheep meat treated with C. pilosula (0.10%) and A. capillaris (0.10%) were lower than those of meat treated with other extracts.

One hundred and twelve samples of raw buffalo milk were collected at four locations in China, and their microbiological and chemical composition was analyzed. Average levels of major components were: fat 7.59% (v/v), crude protein 4.86% (w/w), lactose 4.74% (w/w), total solids 18.44% (w/w), ash 0.85% (w/w), and pH 6.65. The crude protein, fat, total solids and ash contents of milk from multi-crossbreed buffalo were higher than those of river buffalo’s, but lower than those of crossbreed F 1 and F 2 buffalo’s. Microbiological enumeration revealed counts of total mesophilic aerobic bacteria of 5.59 log cfu/ml, bacterial endospores 2.31, lactic acid bacteria 4.62, fungi 1.79, coliforms 2.42, Escherichia coli 1.53, and Staphylococcus aureus 1.68. Listeria spp. were below detection level in all of the samples. The microbiological quality of buffalo milk was judged marginal and indicates the need for improved hygienic standards.

The immunoactivity was evaluated of Dendrobium officinale Kimura & Migo, a Chinese herbal plant, and its crude polysaccharides. Different dosages of D. officinale and its polysaccharides were orally administered to healthy BALB/c mice. The control group was given distilled water. After 4 weeks, immune parameters, including cellular immunity (delayed-type hypersensitivity and natural killer cell activity), humoral immunity (serum hemolytic complement activity), nonspecific immunity (peritoneal macrophage phagocytosis) and interferon-γ production by splenocytes were measured. The results showed that D. officinale and its polysaccharides can significantly enhance cellular immunity and nonspecific immunity in mice. Humoral immunity was also enhanced after oral administration of D. officinale, but the polysaccharides had no influence. Both D. officinale and its polysaccharides markedly increased IFN-γ production by murine splenocytes. Six fractions were isolated from the polysaccharides; the molecular weight of the major fraction was 533,700 Da, and composed of mannose, glucose and rhamnose in a molar ratio of 7.3:1.3:1.0.