Study of the weak interaction mechanism of ovalbumin and caffeic acid using fluorescence spectroscopy and molecular dynamics simulation.

With the increasing demand for functional foods, the study on binding of active molecules and ovalbumin (OVA) via weak interaction has attracted widespread attention. In this work, the interaction mechanism of OVA and caffeic acid (CA) was revealed using fluorescence spectroscopy and dynamics simulation. The CA-induced fluorescence decrease of OVA was static quenching. Their binding complex had about 1 binding site and a 3.39 × 105 L·mol-1 affinity ability. Based on thermodynamic calculations and molecular dynamics simulation, the complex structure of OVA and CA were stable using hydrophobic interactions as the main force, where CA preferred to interact with a stable binding pocket consisting of E256, E25, and V200 with N24 amino acid residues. In the binding process of CA and OVA, the conformation of OVA was altered with a slight reduction of α-helix and ß-sheet. The reduced molecular volume and more compact structure of the protein indicated that CA is beneficial to the structural stability of OVA. The research provides some new insights into the interaction between dietary proteins and polyphenols, expanding the application prospects of OVA as a carrier.

Processing of four different cooking methods of Oudemansiella radicata: Effects on in vitro bioaccessibility of nutrients and antioxidant activity.

The purpose of this study is to evaluate the bioaccessibility of nutrients and antioxidant activity of O. radicata after subjecting to four types of domestic cooking and followed by in vitro digestion. The result demonstrated that the group with the lowest amino acid release and the degree of protein hydrolysis (5.6%) was frying, but both reducing sugar content and antioxidant activity were the highest. The composition of fatty acids was different than undigested samples, especially the relative content of linolenic acid was significantly decreased (e.g., 34.49 to 8.23%, boiled). The difference of the minerals bioaccessibility was slightly affected by the cooking method, but mainly related to their natural properties, such as the highest phosphorus (62.73%) and the lowest iron (21.53%) in the steaming. The above data provides a starting point for the design of processes at an industrial and gastronomic level.

Novel vaccine design based on genomics data analysis: A review.

Modification of pathogenic strains with the passage of time is responsible for evolution in the timeline of vaccine development for last 30 years. Recent advancements in computational vaccinology on the one hand and genome sequencing approaches on the other have generated new hopes in vaccine development. The aim of this review was to discuss the evolution of vaccines, their characteristics and limitations. In this review, we highlighted the evolution of vaccines, from first generation to the current status, pointing out how different vaccines have emerged and different approaches that are being followed up in the development of more rational vaccines against a wide range of diseases. Data were collected using Google Scholar, Web of Science, Science Direct, Web of Knowledge, Scopus and Science Hub, whereas computational tools such as NCBI, GeneMANIA and STRING were used to analyse the pathways of vaccine action. Innovative tools, such as computational tools, recombinant technologies and intra-dermal devices, are currently being investigated in order to improve the immunological response. New technologies enlightened the interactions of host proteins with pathogenic proteins for vaccine candidate development, but still there is a need of integrating transcriptomic and proteomic approaches. Although immunization with genomics data is a successful approach, its advantages must be assessed case by case and its applicability depends on the nature of the agent to be immunized, the nature of the antigen and the type of immune response required to achieve effective protection.

Preparation and characterization of Konjac glucomannan and pullulan composite films for strawberry preservation.

The present study aims to develop the new composite films by blending Konjac glucomannan (KGM) and pullulan with different ratios and concentrations. The structural, physical, barrier properties and morphology of the films were investigated and the practical use on strawberry preservation at 4 ± 1 °C, 85 %±5% relative humidity (RH) and 25 ± 1 °C, 55 %±5% RH was evaluated. Fourier transform infrared and scanning electron microscopy indicated the well-dispersion of film matrix was due to the good compatibility of the components. The mechanical and barrier properties of blend films were markedly enhanced although the light transmittance of which were decreased slightly. It was a further proof that 1% (w/v) KGM/pullulan (with the mass ratio of 2:1) blend film could decrease the weight loss significantly and maintain the titratable acidity, soluble solids and skin color on the strawberry preservation, thus improving the qualities of strawberries during storage time and offering a potential alternative to synthetic materials.

Effects of polyphosphates and sodium chloride on heterocyclic amines in roasted beef patties as revealed by UPLC-MS/MS.

The effects of sodium tripolyphosphate (TPP), sodium pyrophosphate (PP), and NaCl at different ionic strengths on the formation of heterocyclic amines (HAs) were investigated in roasted beef patties. Six HAs (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine [PhIP], 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline [MeIQx], 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline [4,8-DiMeIQx], 2-amino-3-methylimidazo[4,5-f]quinoline [IQ], 1-methyl-9H-pyrido[3,4-b] indole [harman], and 9H-pyrido[3,4-b] indole [norharman]) were identified and quantified. The presence of 0.3% and 0.45% PP significantly increased the formation of PhIP (P < 0.05). Different levels of TPP/PP had no effect on MeIQx, 4,8-DiMeIQx, IQ, norharman, or harman (P > 0.05), but these products increased in the presence of NaCl at three ionic strengths and NaCl + 0.3% and 0.45% TPP/PP (P < 0.05). High hardness and surface temperatures were observed after treatments with NaCl and NaCl + TPP/PP. The increase in these six HAs in beef patties with the addition of polyphosphates and NaCl did not involve changes in pH, but mainly stemmed from higher surface temperatures during roasting.

Starch phosphorylation and the in vivo regulation of starch metabolism and characteristics.

Starch is the most significant carbon and energy reserve in plants and is also a sustainable feedstock for many industrial applications. Substantial research effort has been devoted to enhancing the yield and quality of starch. Over the past century, starch phosphorylation has aroused increasing interest as the only naturally occurring covalent modification in starch. Many studies have investigated the role of phosphorylation in starch metabolism and its impact on the starch granule. In this review, the two key enzymes involved in starch phosphorylation and their catalytic mechanisms are described at the molecular level; the vital roles of phosphorylation in starch degradation and biosynthesis are illuminated in detail; and the multiple influences of phosphorylation on starch composition, granule structure and physicochemical properties are discussed. This review systematically summarizes the importance of phosphorylation in starch metabolism, and describes the advanced methods used to precisely measure phosphate and increase the level of starch phosphorylation.

Preparation and characterization of chitosan films with three kinds of molecular weight for food packaging.

Recently, chitosan film has been widely used to extend the shelf life of food. In this study, high, medium and low molecular weight of chitosan were used as raw materials to prepare a series of films (C1-C27) by controlling the content of chitosan and glycerol, and their mechanical properties, water vapor permeability (WVP), oxygen transmittance (OP), morphology and antibacterial properties were characterized as well. The results indicated that all films had film-forming properties. Among them, the film C16 with high molecular weight, high chitosan content and 50% glycerol/chitosan (w/w) exhibited the excellent transparency (91.2%), elongation at break (28.948%), tensile strength (77.963 MPa), WVP (1.46 × 10-12gcm/cm2·sPa), smooth morphology, denser structure and antibacterial property (Staphylococcus aureus and Escherichia coli). Meanwhile, the preservation properties of chitosan films were evaluated by strawberry preservation. Almost all the studied films had better preservation effect than the commercially available PE films, especially of which the film C16 was the best compared with others. It maintained the physical and chemical parameters (weight loss ratio, total soluble solids, titratable acidity, total ascorbic acid and color change) of strawberry most obviously. Hence, chitosan films had great potential for the industrial application of fruit preservation.

The Roles of GABA in Ischemia-Reperfusion Injury in the Central Nervous System and Peripheral Organs.

Ischemia-reperfusion (I/R) injury is a common pathological process, which may lead to dysfunctions and failures of multiple organs. A flawless medical way of endogenous therapeutic target can illuminate accurate clinical applications. γ-Aminobutyric acid (GABA) has been known as a marker in I/R injury of the central nervous system (mainly in the brain) for a long time, and it may play a vital role in the occurrence of I/R injury. It has been observed that throughout cerebral I/R, levels, syntheses, releases, metabolisms, receptors, and transmissions of GABA undergo complex pathological variations. Scientists have investigated the GABAergic enhancers for attenuating cerebral I/R injury; however, discussions on existing problems and mechanisms of available drugs were seldom carried out so far. Therefore, this review would summarize the process of pathological variations in the GABA system under cerebral I/R injury and will cover corresponding probable issues and mechanisms in using GABA-related drugs to illuminate the concern about clinical illness for accurately preventing cerebral I/R injury. In addition, the study will summarize the increasing GABA signals that can prevent I/R injuries occurring in peripheral organs, and the roles of GABA were also discussed correspondingly.

In Vitro Antioxidant Activity of Peptides from Simulated Gastro-Intestinal Digestion Products of Cyprinus carpio haematopterus Scale Gelatin.

A two-stage simulated gastro-intestinal (GI) digestion model (2 h pepsin treatment and subsequent 2 h pancreatin treatment at 37 °C) was used to explore the antioxidant activity of the digested products of Cyprinus carpio haematopterus scale gelatin with different molecular weights (MW). From the gastric phase to the intestinal phase, the hydrolysis degree of the products increased from 2.6 ± 0.4% to 16.9 ± 0.7%. The fraction of 0-1 kDa (JCP3) exhibited the best antioxidant activities in hydroxyl radical scavenging, reducing power, and metal chelating activity. The fraction of 1-3 kDa (JCP2) exhibited the best 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. However, the fractions of 0-1 kDa (JCP3) and 1-3 kDa (JCP2) showed similar inhibitory activity of lipid peroxidation. The results indicated that Cyprinus carpio haematopterus scale gelatin can be digested in the gastrointestinal tract. Furthermore, the digested products had antioxidant activity.

System-Wide Characterization of MoArf GTPase Family Proteins and Adaptor Protein MoGga1 Involved in the Development and Pathogenicity of Magnaporthe oryzae.

ADP ribosylation factor (Arf) small GTPase family members are involved in vesicle trafficking and organelle maintenance in organisms ranging from Saccharomyces cerevisiae to humans. A previous study identified Magnaporthe oryzae Arf6 (MoArf6) as one of the Arf proteins that regulates growth and conidiation in the rice blast fungus M. oryzae, but the remaining family proteins remain unknown. Here, we identified six additional Arf proteins, including MoArf1, MoArl1, MoArl3, MoArl8, MoCin4, and MoSar1, as well as their sole adaptor protein, MoGga1, and determined their shared and specific functions. We showed that the majority of these proteins exhibit positive regulatory functions, most notably, in growth. Importantly, MoArl1, MoCin4, and MoGga1 are involved in pathogenicity through the regulation of host penetration and invasive hyphal growth. MoArl1 and MoCin4 also regulate normal vesicle trafficking, and MoCin4 further controls the formation of the biotrophic interfacial complex (BIC). Moreover, we showed that Golgi-cytoplasm cycling of MoArl1 is required for its function. Finally, we demonstrated that interactions between MoArf1 and MoArl1 with MoGga1 are important for Golgi localization and pathogenicity. Collectively, our findings revealed the shared and specific functions of Arf family members in M. oryzae and shed light on how these proteins function through conserved mechanisms to govern growth, transport, and virulence of the blast fungus.IMPORTANCEMagnaporthe oryzae is the causal agent of rice blast, representing the most devastating diseases of rice worldwide, which results in losses of amounts of rice that could feed more than 60 million people each year. Arf (ADP ribosylation factor) small GTPase family proteins are involved in vesicle trafficking and organelle maintenance in eukaryotic cells. To investigate the function of Arf family proteins in M. oryzae, we systematically characterized all seven Arf proteins and found that they have shared and specific functions in governing the growth, development, and pathogenicity of the blast fungus. We have also identified the pathogenicity-related protein MoGga1 as the common adaptor of MoArf1 and MoArl1. Our findings are important because they provide the first comprehensive characterization of the Arf GTPase family proteins and their adaptor protein MoGga1 functioning in a plant-pathogenic fungus, which could help to reveal new fungicide targets to control this devastating disease.

Polyphenols extract from lotus seedpod (Nelumbo nucifera Gaertn.): Phenolic compositions, antioxidant, and antiproliferative activities.

Seedpod, the nonedible portion of lotus (Nelumbo nucifera Gaertn.), was reported to be rich in polyphenols. The objective of this study was to investigate the major bioactive polyphenols of the lotus seedpods. The total polyphenol content (TPC) from ethanol extract of lotus seedpod (PELS) was found to be 34.23 µg gallic acid equivalents (GAE)/mg extract. Four polyphenolic compounds were identified in the PELS, comprised of one flavan-3-ol (catechin) and three flavonoids (kaemferol, quercetin and hyperoside). In vitro antioxidant and antiproliferative properties of the PELS were evaluated. PELS exhibited 89.38%, 99.82%, 68.25%, and 95.82% scavenging activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide, hydroxyl, and 2,2'azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals, respectively, at 1.6 mg/ml. The Fe3+ reducing power of PELS was 0.605 at 0.32 mg/ml, which is comparable to glutathione (GSH). The PELS showed 31.79% metal chelating capacity and 87.79% inhibition of linoleic acid auto-oxidation at 1.6 mg/ml. PELS showed cytotoxicity toward HepG2 and LNcap cell lines in vitro with IC50 values at 44.59 and 11.50 µg/ml, respectively. The findings of this study provide evidences that the inedible lotus seedpod could be a source for natural antioxidants and anticancer agents.

Roles of taurine in cognitive function of physiology, pathologies and toxication.

Taurine is a key functional amino acid with many functions in the nervous system. The effects of taurine on cognitive function have aroused increasing attention. First, the fluctuations of taurine and its transporters are associated with cognitive impairments in physiology and pathology. This may help diagnose and treat cognitive impairment though mechanisms are not fully uncovered in existing studies. Then, taurine supplements in cognitive impairment of different physiologies, pathologies and toxicologies have been demonstrated to significantly improve and restore cognition in most cases. However, elevated taurine level in cerebrospinal fluid (CSF) by exogenous administration causes cognition retardations only in physiologically sensitive period between the perinatal to early postnatal period. In this review, taurine levels are summarized in different types of cognitive impairments. Subsequently, the effects of taurine supplements on cognitions in physiology, different pathologies and toxication of cognitive impairments (e.g. aging, Alzheimer' disease, streptozotocin (STZ)-induced brain damage, ischemia model, mental disorder, genetic diseases and cognitive injuries of pharmaceuticals and toxins) are analyzed. These data suggest that taurine can improve cognition function through multiple potential mechanisms (e.g. restoring functions of taurine transporters and γ-aminobutyric acid (GABA) A receptors subunit; mitigating neuroinflammation; up-regulating Nrf2 expression and antioxidant capacities; activating Akt/CREB/PGC1α pathway, and further enhancing mitochondria biogenesis, synaptic function and reducing oxidative stress; increasing neurogenesis and synaptic function by pERK; activating PKA pathway). However, more mechanisms still need explorations.

Formation of Nε-(carboxymethyl)lysine and Nε-(carboxyethyl)lysine during black tea processing.

This study selected common processing methods for orthodox black tea and investigated changes in the levels of Nε-(carboxymethyl)lysine (CML), Nε-(carboxyethyl)lysine (CEL), lysine, and polyphenols during each processing stage and using different parameters of each processing step. The effects of epicatechin gallate, epigallocatechin, epigallocatechin gallate, and gallic acid on the levels of CML, CEL, fructoselysine, glyoxal, and methylglyoxal were investigated by chemical model systems study under black tea processing conditions. In tea samples, CML and CEL levels significantly increased during drying (could reach 51.8 and 8.7 µg/g tea, respectively), while natural withering and extensive rolling and fermentation times facilitated the formation of CML and CEL by altering the substrate concentrations and the cellular structure of tea leaves to be dried. The results of model systems (containing lysine, glucose, and fructose) indicated that polyphenols were able to enhance the production of CML and CEL, and the levels of CML and CEL increased 1.2-3.2- and 1.6-3.5-fold, respectively. Furthermore, the main pathways responsible for CML and CEL formation during black tea processing likely involve fructoselysine and others but not glyoxal or methylglyoxal.

The ArfGAP protein MoGlo3 regulates the development and pathogenicity of Magnaporthe oryzae.

The ADP ribosylation factor (Arf) and the coat protein complex I (COPI) are involved in vesicle transport. Together with GTPase-activating proteins (ArfGAPs) and guanine exchange factors (ArfGEFs) that regulate the activity of Arf, they govern vesicle formation, COPI trafficking and the maintenance of the Golgi complex. In an ongoing effort to study the role of membrane trafficking in pathogenesis of the rice blast fungus Magnaporthe oryzae, we identified MoGlo3 as an ArfGAP protein that is homologous to Glo3p of the budding yeast Saccharomyces cerevisiae. As suspected, MoGlo3 partially complements the function of yeast Glo3p. Consistent with findings in S. cerevisiae, MoGlo3 is localized to the Golgi, and that the localization is dependent on the conserved BoCCS domain. We found that MoGlo3 is highly expressed during conidiation and early infection stages and is required for vegetative growth, conidial production and sexual development. We further found that the ΔMoglo3 mutant is defective in endocytosis, scavenging of the reactive oxygen species, and in the response to endoplasmic reticulum (ER) stress. The combined effects result in failed appressorium function and decreased pathogenicity. Moreover, we provided evidence showing that the domains including the GAP, BoCCS and GRM are all important for normal MoGlo3 functions. Our studies further illustrate the importance of normal membrane trafficking in the physiology and pathogenicity of the rice blast fungus.

Nε-(carboxymethyl)lysine and Nε-(carboxyethyl)lysine in tea and the factors affecting their formation.

The levels of Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL) in 99 tea samples from 14 geographic regions, including 44 green, 7 oolong, 41 black, and 7 dark teas were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The CML and CEL contents varied from 11.0 to 1701µg/g tea and 4.6 to 133µg/g tea, respectively. Dark tea presented the highest levels of CML and CEL, whereas green and oolong teas presented the lowest levels. Five kinds of catechins in the tea were also analyzed, and spearman's correlation coefficients showed that all the catechins negatively correlated with CML and CEL. The results suggested that withering, fermentation and pile fermentation may facilitate the formation of CML and CEL. Catechins might inhibit the formation of CML and CEL, but their inhibitory effects may be affected by tea processing. The results of this study are useful for the production of healthier tea.

Preparation of tyrosinase inhibitors and antibrowning agents using green technology.

Chalcones and their derivatives have attracted great interests in recent years for their comprehensive biological activities. In this study, 2,4,2',4'-tetrahydroxychalcone and its two derivatives, 1,3,5-tris-(2,4-dihydroxy-phenyl)pentane-1,5-dione (new compound) and 7,2',4'-trihydroxyflavanone, were synthesized through one-pot green procedure catalyzed by boric acid in polyethylene glycol 400. Their structures were identified by ESI-MS and NMR spectral. Tyrosinase inhibitory activity and antibrowning test results showed that compounds 1-3 exhibited strong tyrosinase inhibitory activities and significant antibrowning effects on the fresh-cut lotus root slices at room temperature in 48 h. Among them, 0.01% 1,3,5-tris-(2,4-dihydroxy-phenyl)pentane-1,5-dione combined with 0.5% VC showed the best antibrowning ability. In brief, this study offers a protocol for one-pot green synthesis of high efficiency tyrosinase inhibitors which may be suitable as antibrowning agents for fresh-cut vegetables. More important, this study developed a new type of 1,5-dione derivative which may serve as new lead structures for novel tyrosinase inhibitors discovery.