Enzymatic hydrolysis of silkworm pupa and its allergenicity evaluation by animal model with different immunization routes

Silkworm pupa is a nourishing food with high nutritional value,but its consumption has been greatly limited given its allergenicity.Enzyme hydrolytic technique is recognized as an effective method to reduce the allergenicity of protein.In this study,we aimed to investigate the effect of enzymolysis on the allergenicity of silkworm pupa.Crude silkworm pupa protein was extracted through alkali extraction and acid precipitation,which included 5 proteins with the molecular weights ranging from 34 kDa to 76 kDa,and silkworm pupa were then hydrolyzed by alkaline protease.The allergenicity of silkworm pupa protein and its enzymatic hydrolysates was evaluated by establishing BALB/c mice model,and the mice were immunized via intragastric gavage and intraperitoneal injection,respectively.The results indicated that the intraperitoneal inj ection immunization route induced more by detecting with antibodies,histamine and Th2-related cytokines.Moreover,mice treated with silkworm pupa protein peptide displayed no obvious allergic symptoms,indicating that enzyme hydrolytic technique could significantly reduce the allergenicity of silkworm pupa.

COS hydrolysis in the presence of oxygen:Experiment and modeling

A mathematical model of COS hydrolysis on Al2O3, with fouling of catalyst, has been developed. Kinetic studies were carried out in a fixed bed reactor under atmospheric pressure and low temperature （40-70℃）. The effects of the COS inlet concentration, temperature, and relative humidity were analyzed. Experimental results of breakthrough curves were used to obtain kinetic parameters, which accounted for effects of S deposition on the inner-face of the catalyst. The model described the experimental breakthrough curves satisfactorily and well explained the performance of COS hydrolysis in the presence of oxygen. The exothermic heat of adsorption and activation energy, assuming Arrhenius type of temperature dependence of the equilibrium constant, were determined. Activation energy of COS hydrolysis and H2S oxidation were 35.9 kJ/mol, 19.6 kJ/mol; adsorption heat of H2O and H2S on Al2O3 were 45.1 and 60.1 kJ/mol respectively. Deactivation coefficient （α） was used to quantify the behavior of COS hydrolysis at different operating conditions. The effect of relative humidity on α is significant in the relative humidity range under study. Experimental data accorded well with model data in the studied range.

Mechanism and kinetics model of hydrolysis in anaerobic digestion of kitchen wastes

The profile of hydrolysates during the anaerobic digestion of kitchen wastes was investigated. The experimental results show that the hysteresis of hydrolytic rate is mainly controlled by the diffusion effect. The hydrolytic mechanism of kitchen wastes is elaborated by taking the diffusion effect into consideration. A segment model of the hydrolysis for kitchen waste is formulated including the coefficient of diffusion resistance in the model. The coefficients of diffusion resistance for different particle sizes are 1.42,2.12 and 2.78 respectively based on the experimental data,in which the coefficients of diffusion resistance conform an exponential function. So,the partitioning kinetic model could be integrated as a unified experience model. The model is verified with experimental data,which shows that the model could predict the concentration of organic substances during the anaerobic digestion of kitchen wastes.

Study on Hydrolysis of Methyl Acetate in a Catalytic Distillation Column

A nonequilibrium stage model was used to simulate countercurrent multicomponent catalytic distillation processes for methyl acetate hydrolysis. Computations of stage eiliciencies or height equivalent to a theoretical plate (HETP) were entirely avoided by this model. The consistency of simulated results and experimental data in conversions and concentration of each component along a column indicates that the model predicts the actual process well. The influences of operating parameters on hydrolytic conversions, such as feed molar ratios, feed locations, feed and reflux rates, heights of reactive and stripping sections, were analyzed adequately by simulating calcuiations. A good operating mode was then obtained, which is helpful to the development of a new process.

Kinetic study of alkaline protease 894 for the hydrolysis of the pearl oyster Pinctada martensii

A new enzyme (alkaline protease 894) obtained from the marine extremophile Flavobacterium yellowsea (YS-80-122) has exhibited strong substrate-binding and catalytic activity, even at low temperature, but the characteristics of the hydrolysis with this enzyme are still unclear. The pearl oyster Pinctada martensii was used in this study as the raw material to illustrate the kinetic properties of protease 894. After investigating the intrinsic relationship between the degree of hydrolysis and several factors, including initial reaction pH, temperature, substrate concentration, enzyme concentration, and hydrolysis time, the kinetics model was established. This study showed that the optimal conditions for the enzymatic hydrolysis were an initial reaction pH of 5.0, temperature of 30°C, substrate concentration of 10% (w/v), enzyme concentration of 2 500 U/g, and hydrolysis time of 160 min. The kinetic characteristics of the protease for the hydrolysis of P. martensii were obtained. The inactivation constant was found to be 15.16/min, and the average relative error between the derived kinetics model and the actual measurement was only 3.04%, which indicated a high degree of fitness. Therefore, this study provides a basis for the investigation of the concrete kinetic characteristics of the new protease, which has potential applications in the food industry.

A possible hydrolysis mechanism of β-naphthyl acetate catalyzed by antibodies

The mechanism of ester hydrolysis has been extensively studied; however, the precise function of active-site residues in promoting catalysis is nuclear. We describe here the structural models for the complex of a catalytic sntibody Fv fragment with a phosphonate transition -state analogue, constructed by using gene cloning, sequencing and molecular modeling, mainly based on a known X-ray structure of a catalytic atibody. Hydrophobic and electrostatic analyses of the Fv/analog and Fv/substrate interaction suggest the hydrolysis mechanism: In L91 and Tyr H97 play important roles to stabilize the β-naphthyl group of hapten through r-stack; His H35 donates a pair of free electrons at the atom NEZ to an active water and let it to be a partial hydroxide, which attacks the carbon atom of the carbonyl group of the substrate. Both His H35 and Arg L96 can form hydrogen bonds and stabilize the Anoinc tetrahedral intermediate formed during turnover. This mechanism emphasizes that an active water bridge may be formed during hydrolysis process.

核桃粕源抗氧化活性肽的酶解制备及活性分析

目的:深度利用核桃粕蛋白。方法:采用分级分离法从核桃粕中提取蛋白质后,分别用胰蛋白酶、木瓜蛋白酶、中性蛋白酶、碱性蛋白酶和风味蛋白酶5种蛋白酶对其进行水解,并比较分析胰蛋白酶酶解物(trypsin hydrolysate,TH)、木瓜蛋白酶酶解物(papain hydrolysate,PH)、中性蛋白酶酶解物(dispase hydrolysate,DH)、碱性蛋白酶酶解物(alcalase hydrolysate,AH)和风味蛋白酶酶解物(flavourzyme hydrolysate,FPH)的抗氧化活性;以DPPH自由基清除率、ABTS自由基清除率和羟自由基清除率为检测指标分析不同浓度AH的体外抗氧化性;采用LC-MS/MS技术鉴定AH中所有肽的序列,并利用PeptideRanker、BIOPEP-UWM数据库和分子对接工具AutoDock1.5.6筛选潜在的核桃抗氧化活性肽;将上述两条肽分别与Keap1蛋白进行计算机模拟分子对接,并利用斑马鱼胚胎氧化损伤模型,对人工合成的两条抗氧化活性肽的抗氧化活性进行分析。结果:5种酶解物中抗氧化活性较好的AH对DPPH自由基、ABTS自由基和羟自由基的最佳清除率分别为(71.56±0.75)%,(60.63±0.45)%,(98.63±0.06)%。LC-MS/MS鉴定并通过计算机分析预测得到两条活性最优的肽,即:ALWPF和PLRWPF;两条抗氧化活性肽均能与Keap1蛋白的活性部位结合,其结合能分别为-9.2,-9.6 kJ/mol。ALWPF和PLRWPF肽处理斑马鱼胚胎的安全质量浓度范围分别为0~50,0~30μg/mL。结论:从核桃粕中鉴定出两条抗氧化肽,其对斑马鱼胚胎具有保护作用。

On the Parameterization of Convective Entrainment: Inherent Relationships among Entrainment Parameters in Bulk Models

In this paper, the equilibrium entrainment into a shear-free, linearly stratified atmosphere is discussed under the framework of bulk models, namely, the zero-order jump model （ZOM） and the first-order jump model （FOM）. The parameterizations for the dimensionless entrainment rate versus the convective Richard- son number in the two models are compared. Based on the assumption that the parameterized entrainment rates in ZOM and FOM should be the same, the inherent relationships among the entrainment parameters in the bulk models are revealed. These relationships are supported by tank experiments and large-eddy sim- ulations. The validity of these inherent relationships indicates that, for a convective boundary layer growing into a linearly stratified free atmosphere, the only dominant factors of the growth rate are the turbulent buoyancy in the mixed layer and the stratification in the free atmosphere. In the point of the similarity view, the former is characterized by turbulent temperature and mixing length scales （mixed layer depth）, and the latter is characterized by the lapse rate of potential temperature in the free atmosphere. Thus, the commonly-used Richardson number scheme for the parameterization of the entrainment rate is just as an equivalent description. The variability of the total entrainment flux ratio in FOM, which is connected with the entrainment zone thickness, can implicitly describe the effect of the stratification in the free atmosphere, but the entrainment zone thickness is not an independent parameter. These results demonstrate the validity of the hypothesis that there exists a similarity limit in which the mixed layer depth is the only lengthscale.

Modeling of degradation kinetics of Salvianolic acid B at different temperatures and pH values

In this work,the effects of degradation time,temperature,and pH value on the degradation of Salvianolic acid B in aqueous solution were determined.Higher pH values,higher extraction temperature,and longer extraction time led to more degradation of Salvianolic acid B.Danshensu concentration increased as Salvianolic acid B degraded.A mechanism model was developed considering the degradation of Salvianolic acid E and lithospermic acid,which were two degradation products of Salvianolic acid B.The reverse reactions of Salvianolic acid B degradation were also considered.Degradation kinetic constants were calibrated.The degradation kinetics of Salvianolic acid B,lithospermic acid,and Danshensu in a Salvia miltiorrhiza extract aqueous solution were predicted using the mechanism model.The predicted concentrations agreed well with the experimental results.This model was developed using degradation data obtained from simple composition systems,but it can be applied in a complex botanical mixture with high prediction accuracy.

Current Model Analysis of South China Sea Based on Empirical Orthogonal Function(EOF) Decomposition and Prototype Monitoring Data

Environmental load is the primary factor in the design of offshore engineering structures and ocean current is the principal environmental load that causes underwater structural failure. In computational analysis, the calculation of current load is mainly based on the current profile. The current profile model, which is based on a structural failure criterion, is conducive to decreasing the uncertainty of the current load. In this study, we used prototype monitoring data and the empirical orthogonal function(EOF) method to investigate the current profile in the South China Sea and its correlation with the design of underwater structural strength and the dynamic design of fatigue. The underwater structural strength design takes into account the size of the structure and the service water depth. We propose profiles for the overall and local designs using the inverse first-order reliability method(IFORM). We extracted the characteristic profile current(CPC) of the monitored sea area to solve dynamic design problems such as vortex-induced vibration(VIV). We used random sampling to verify the feasibility of using the EOF method to calculate the CPC from the current data and identified the main problems associated with using the CPC, which deserve close attention in VIV design. Our research conclusions provide direct references for determining current load in this sea area. This analysis method can also be used in the analysis of other sea areas or field variables.

Mathematical modeling for of arctigenin from acidultrasonic-assisted extractionhydrolyzed FructusArctii

A mathematical model based on Fick＇ s first law wasestablished to describe the process of ultrasonic-assistedextraction of arctigenin from acid hydrolyzed FructusArctii.Acid hydrolization with hydrochloric acid promotes theconversion of arctiin to arctigenin in the arctiin-rich activepharmaceutical ingredient, and the hydrolyzed products werefurther examined to investigate the process setup. Byconsidering the mechanism of the extraction process andexperimental data, the effects of parameters including solventto solid ratio, particle size of hydrolyzed samples, ethanolvolume fraction, ultrasound power, extraction temperature andextraction time on concentration of arctigenin were analyzed indetail. The model was suitable for simulating the process ofultrasonic-assisted extraction of arctigenin. The simulationresults of the model agree well with experimental data with thedeviation below 13%, indicating that the mathematical modelcan provide valuable guidance for the extraction of arctigeninfrom acid hydrolyzed FructusArctii.

Prediction model of slurry pH based on mechanism and error compensation for mineral flotation process

A suitable pH value of the slurry is a key to efficient mineral flotation. Considering the control delay problem of pH value caused by offline pH measurement, an integrated prediction model for pH value in bauxite froth flotation is proposed, which considers the effect of ore compositions on pH value. Firstly, a regression model is obtained for alkali(Na_2CO_3) consumed by the reaction between ore and alkali. According to the first-order hydrolysis of the remaining alkali, a mechanism-based prediction model is presented for the pH value. Then, considering the complexity of the flotation mechanism, an error prediction model which uses time series of the error of the mechanism model as inputs is presented based on autoregressive moving average(ARMA) method to compensate the mechanism model. Finally, expert rules are established to correct the error compensation direction, which could reflect the dynamic changes during the process accurately and effectively. Simulation results using industrial data show that the presented model meets the needs of the industrial process, which laid the foundation for predictive control of pH regulator.

Microcanonical Monte Carlo Simulation of 2D 4-State Potts Model

Monte Carlo simulation of two dimensional 4 state Potts model has been carried out in microcanonical ensemble. The simulations were done on a 30 × 30 system with periodic boundary conditions. The temperature dependence of energy and order parameter has been calculated. The transition in 4-state Potts model is concluded to be first-order in nature. The transition temperature and latent heat of the first-order transition have been found to be 0.92 and 0.18, respectively.

Stochastic Four-State Mechanochemical Model of F_1-ATPase

F_1-ATPase, a part of ATP synthase, can synthesize and hydrolyze ATP moleculars in which the centralγ-subunit rotates inside the α_3β_3 cylinder.A stochastic four-state mechanochemical coupling model of F_1-ATPase isstudied with the aid of the master equation.In this model, the ATP hydrolysis and synthesis are dependent on ATP,ADP, and Pi concentrations.The effects of ATP concentration, ADP concentration, and the external torque on theoccupation probability of binding-state, the rotation rate and the diffusion coefficient of F_1-ATPase are investigated.Moreover, the results from this model are compared with experiments.The mechanochemical mechanism F_1-ATPase isqualitatively explained by the model.

喷施污泥热碱液对叶菜产量及氮转化酶的影响

污泥通过碱性热水解工艺(ATH)提取的富含多肽、蛋白质类的液体已被证实无毒性,用于农业生产中可显著促进作物生长。为研究该液体对作物氮素吸收的影响及其同化机制,以小青菜为研究对象,以喷施清水为对照,研究了200、400、600、800倍和1000倍5个稀释倍数处理条件下喷施热碱液对小青菜产量、氮素养分吸收及氮同化关键酶活性的影响。结果表明:随着喷施热碱液稀释倍数的增加,各指标均呈先升高后降低的趋势,当热碱液稀释400倍时,小青菜收获后,其氮素累积量、叶绿素相对含量(SPAD值)和产量等达到较高水平,且小青菜中硝酸还原酶(NR)、亚硝酸还原酶(NiR)、谷氨酸脱氢酶(GDH)、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)在生育期间均可保持较高的活性;偏最小二乘路径模型(PLS-PM)表明,喷施热碱液后小青菜的氮素吸收主要受NR、GS、GOGAT的影响,同时GOGAT对小青菜产量的提升有显著作用。研究表明,喷施适宜稀释倍数的热碱液会提高小青菜氮素同化相关酶的活性,促进小青菜生长和对养分的吸收,从而提高产量。

酶水解法制备黄芪素及应用研究

探讨酶水解法制备黄芪素及其应用研究。以黄芪素的提取率为评价指标,采用酶水解法提取黄芪素,使用高效液相色谱仪(HPLC)进行测定。通过构建衰老模型小鼠,将酶水解法制备的黄芪素作用于衰老模型小鼠,观察衰老模型小鼠学习记忆能力及脑组织氧化水平检测。结果显示,酶水解法正交试验较优条件为:当料液比1∶10,提取次数3次,提取温度80℃,提取时间1 min时,黄芪素提取率最高。与对照组相比,黄芪素作用衰老模型小鼠后,能够显著改善其学习记忆能力(P<0.05);经黄芪素处理后,衰老模型小鼠脑组织中超氧化物歧化酶(SOD)和过氧化氢酶(CAT)含量显著增加(P<0.05),而丙二醛(MDA)含量显著下降(P<0.05)。本研究中,通过优化黄芪素制备方法,并检测了黄芪素抗衰老能力,该研究为将来黄芪素的进一步开发和临床应用奠定了理论和实践基础。

Renormalization-group theory of first-order phase transition dynamics in field-driven scalar model

Through a detailed study of the mean-field approximation, the Gaussian approximation, the perturbation expansion, and the field-theoretic renormalization-group analysis of a φ^3 theory, we show that the instability fixed points of the theory, together with their associated instability exponents, are quite probably relevant to the scaling and universality behavior exhibited by the first-order phase transitions in a field-driven scalar Ca model, below its critical temperature and near the instability points. Finite- time scaling and leading corrections to the scaling are considered. We also show that the instability exponents of the first-order phase transitions are equivalent to those of the Yang-Lee edge singularity, and employ the latter to improve our estimates of the former. The outcomes agree well with existing numerical results.

Bubble nucleation in the two-flavor quark-meson model

We investigate the dynamics of a first-order quark-hadron transition via homogeneous thermal nucleation in the two-flavor quark-meson model.The contribution of the fermionic vacuum loop in the effective thermodynamics potential and phase diagram,together with the location of the critical endpoint(CEP),is obtained in the temperature and chemical potential plane.For weak and strong first-order phase transitions,by taking the temperature as a variable,the critical bubble profiles,evolutions of the surface tension,and saddle-point action in the presence of a nucleation bubble are numerically calculated in detail when fixing the chemical potentials atμ=306 MeV andμ=309 MeV.Our results show that the system could be trapped in the metastable state for a long time as long as the temperature is between the metastable region characterized by the up and low spinodal lines.Moreover,the surface tension at criticality will rise to approximately 4 MeV/fm2 when the chemical potential is very high.Such a small surface tension value would favor a mixed phase in the cores of compact stars and may have an important implication in astrophysics.

Synthesis of dimeric estradiol enzyme model containing imidazolyl and study on its catalytic efficiency in hydrolysis of carboxylates and phosphates

Dimeric estradiol enzyme model (2) was synthesized by etherification of 2,4-bis(N-imidazolylmethyl)-17β-estradiol (1) with 1,3-dibromopropane in the presence of anhydrous K2CO3. Hydrolysis of carboxylates and phosphates catalyzed by the model showed Michaelis-Menten kinetic behavior. Hydrophobic interaction between the model and ester accelerates the hydrolysis markedly, rate enhancement of up to 65 and 285 fold, relative to imidazole, is observed.

Establishment and verification of a shrinking core model for dilute acid hydrolysis of lignocellulose

The kinetics oflignocellulose hydrolysis under the conditions of high temperature and dilute acid （mass fraction 0.05%） was investigated in this paper. By studying the reducing sugar concentration versus reaction tempera ture （170℃-220℃） and reaction time （150-1800 s） during the hydrolysis process of five kinds of crop straw （rice, wheat, cotton, rape and corn）, the shrinking core model was established, and the differential equation of the model and its analytical solution were obtained. With a numerical calculation method, the kinetic equation was estimated, and the degradation of reducing sugar obeyed firstorder kinetics was obtained. The calculated results from the equations agreed well with the original experimental data. The calculation by the model showed that the reducing sugar concentration increases as the size of the particles decrease, and the uniform particles increase.