Novel umami peptides from two Termitomyces mushrooms and molecular docking to the taste receptor T1R1/T1R3

Wild edible Termitomyces mushrooms are popular in Southwest China and umami is important flavor qualities of edible mushrooms.This study aimed to understand the umami taste of Termitomyces intermedius and Termitomyces aff.bulborhizus.Ten umami peptides from aqueous extracts were separated using a Sephadex G-15 gel filtration chromatography.The intense umami fraction was evaluated by both sensory evaluation and electronic tongue.They were identified as KLNDAQAPK,DSTDEKFLR,VGKGAHLSGEH,MLKKKKLA,SLGFGGPPGY,TVATFSSSTKPDD,AMDDDEADLLLLAM,VEDEDEKPKEK,SPEEKKEEET and PEGADKPNK.Seven peptides,except VEDEDEKPKEK,SPEEKKEEET and PEGADKPNK were selectively synthesized to verify their taste characteristics.All these 10 peptides had umami or salt taste.The 10 peptides were conducted by molecular docking to study their interaction with identified peptides and the umami taste receptor T1R1/T1R3.All these 10 peptides perfectly docked the active residues in the T1R3 subunit.Our results provide theoretical basis for the umami taste and address the umami mechanism of two wild edible Termitomyces mushrooms.

Taste sensitivity, nutritional status and metabolic syndrome: Implication in weight loss dietary interventions

AIM: We investigated the relationship between taste sensitivity, nutritional status and metabolic syndrome and possible implications on weight loss dietary program. METHODS: Sensitivity for bitter, sweet, salty and sour tastes was assessed by the three-Alternative-Forced-Choice method in 41 overweight(OW), 52 obese(OB) patients and 56 normal-weight matched controls. OW and OB were assessed also for body composition(by impedence), resting energy expenditure(by indirect calorimetry) and presence of metabolic syndrome(MetS) and were prescribed a weight loss diet. Compliance to the weight loss dietary program was defined as adherence to control visits and weight loss ≥ 5% in 3 mo. RESULTS: Sex and age-adjusted multiple regression models revealed a significant association between body mass index(BMI) and both sour taste(P < 0.05) and global taste acuity score(GTAS)(P < 0.05), with lower sensitivity with increasing BMI. This trend in sensitivity for sour taste was also confirmed by the model refitted on the OW/OB group while the association with GTAS was marginally significant(P = 0.06). MetS+ subjects presented higher thresholds for salty taste when compared to MetS- patients while no significant difference was detected for the other tastes and GTAS. As assessed by multiple regression model, the association between salty taste and MetS appeared to be independent of sex, age and BMI. Patients continuing the program(n = 37) did not show any difference in baseline taste sensitivity when compared to drop-outs(n = 29). Similarly, no significant difference was detected between patients reporting and not reporting a weight loss ≥ 5% of the initial body weight. No significant dif-ference in taste sensitivity was detected even after dividing patients on the basis of nutritional(OW and OB) or metabolic status(MetS+ and MetS-). CONCLUSION: There is no cause-effect relationship between overweight and metabolic derangements. Taste thresholds assessment is not useful in predicting the outcome of a diet-induced weight loss program.

Three novel umami peptides derived from the alcohol extract of the Pacific oyster(Crassostrea gigas):identification,characterizations and interactions with T1R1/T1R3 taste receptors

Oyster(Crassostrea gigas),the main ingredient of oyster sauce,has a strong umami taste.In this study,three potential umami peptides,FLNQDEEAR(FR-9),FNKEE(FE-5),and EEFLK(EK-5),were identified and screened from the alcoholic extracts of the oyster using nano-HPLC-MS/MS analysis,i Umami-Scoring Card Method(i Umami-SCM)database and molecular docking(MD).Sensory evaluation and electronic tongue analysis were further used to confirm their tastes.The threshold of the three peptides ranged from 0.38 to 0.55 mg/m L.MD with umami receptors T1R1/T1R3 indicated that the electrostatic interaction and hydrogen bond interaction were the main forces involved.Besides,the Phe592 and Gln853 of T1R3 were the primary docking site for MD and played an important role in umami intensity.Peptides with two Glu residues at the terminus had stronger umami,especially at the C-terminus.These results contribute to the understanding of umami peptides in oysters and the interaction mechanism between umami peptides and umami receptors.

Role of bitter contributors and bitter taste receptors:a comprehensive review of their sources,functions and future development

Bitterness,one of the 5“basic tastes”,is usually undesired by humans.However,abundant literature reported that bitter fruits and vegetables have beneficial health effects due to their bitter contributors.This review provided an updated overview of the main bitter contributors of typical bitter fruits and vegetables and their health benefits.The main bitter contributors,including phenolics,terpenoids,alkaloids,amino acids,nucleosides and purines,were summarized.The bioactivities and wide range of beneficial effects of them on anti-cancers,anti-inflammations,anti-microbes,neuroprotection,inhibiting chronic and acute injury in organs,as well as regulating behavior performance and metabolism were reported.Furthermore,not only did the bitter taste receptors(taste receptor type 2 family,T2Rs)show taste effects,but extra-oral T2Rs could also be activated by binding with bitter components,regulating physiological activities via modulating hormone secretion,immunity,metabolism,and cell proliferation.This review provided a new perspective on exploring and explaining the nutrition of bitter foods,revealing the relationship between the functions of bitter contributors from food and T2Rs.Future trends may focus on revealing the possibility of T2Rs being targets for the treatment of diseases,exploring the mechanism of T2Rs mediating the bioactivities,and making bitter foods more acceptable without getting rid of bitter contributors.

Umami taste components in chicken-spices blends and potential effect of aroma on umami taste intensity

In this study,umami taste intensity(UTI)and umami taste components in chicken breast(CB)and chickenspices blends were characterized using sensory and instrumental analysis.Our main objective was to assess the aroma-umami taste interactions in different food matrices and reconcile the aroma-taste perception to assist future product development.The impact of key aroma,including vegetable-note"2-pentylfuran",meaty"methional",green"hexanal",and spicy-note-estragole and caryophyllene"on UTI was evaluated in monosodium glutamate and chicken extract.We found that spices significantly decreased UTI and umami taste components in CB.Interestingly,the perceptually similar odorants and tastants exhibited the potential to enhance UTI in food matrices.Methional was able to increase the UTI,whereas spicy and green-note components could reduce the UTI significantly.This information would be valuable to food engineers and formulators in aroma selection to control the UTI perceived by consumers,thus,improving the quality and acceptability of the chicken products.

Studies of the Variability of Primary Metabolites in the Epicarp, Mesocarp and Seed of Dacryodes edulis Fruit at Taste Maturity

The fruits of Dacryodes edulis are rich in biologically active substances, which makes them of great interest in terms of validation. In this study, we targeted the primary metabolites in the epicarp, the mesocarp and the seed of the fruit of Dacryodes edulis at taste maturity, which were selected for their nutritional quality and its appreciation throughout the Gulf of Guinea area, which is very popular because of its large size, texture and special taste. The evaluation of total carbohydrates, total lipids and soluble proteins in the epicarp, mesocarp and seed of the fruit at taste maturity was made from spectrophotometer measurements. The overall analysis of the results of the present study shows that total carbohydrates, total lipids and proteins accumulate more in the seed with respectively 251.33 ± 1.15 mg/g DM;9.92 ± 0.201 mg/g DM and 55.075 ± 0.024 mg/g DM. Likewise, the results indicate low concentrations of total carbohydrates and total lipids in the epicarp with respectively 245 ± 1 mg/g DM and 4.77 ± 0.047 mg/g DM, on the other hand, it is the mesocarp which presents the lowest content of soluble proteins: 28.075 ± 3.231 mg/g DM. This variation could be linked to the nature of the compartment, more particularly to the storage location. This comparative study could lead to the valorization of the seed of the fruit of Dacryodes edulis for its richness in metabolites and arouse significant interest in nutrition.

Genetic mutation of Tas2r104/Tas2r105/Tas2r114 cluster leads to a loss of taste perception to denatonium benzoate and cucurbitacin B

Background:Bitter taste receptors(Tas2rs)are generally considered to sense various bitter compounds to escape the intake of toxic substances.Bitter taste receptors have been found to widely express in extraoral tissues and have important physiological functions outside the gustatory system in vivo.Methods:To investigate the physiological functions of the bitter taste receptor cluster Tas2r106/Tas2r104/Tas2r105/Tas2r114 in lingual and extraoral tissues,multiple Tas2rs mutant mice and Gnat3 were produced using CRISPR/Cas9 gene-editing technique.A mixture containing Cas9 and sgRNA mRNAs for Tas2rs and Gnat3 gene was microinjected into the cytoplasm of the zygotes.Then,T7EN1 assays and sequencing were used to screen genetic mutation at the target sites in founder mice.Quantitative real-time polymerase chain reaction(qRT-PCR)and immunostaining were used to study the expression level of taste signaling cascade and bitter taste receptor in taste buds.Perception to taste substance was also studied using twobottle preference tests.Results:We successfully produced several Tas2rs and Gnat3 mutant mice using the CRISPR/Cas9 technique.Immunostaining results showed that the expression of GNAT3 and PLCB2 was not altered in Tas2rs mutant mice.But qRT-PCR results revealed the changed expression profile of m Tas2rs gene in taste buds of these mutant mice.With two-bottle preference tests,these mutant mice eliminate responses to cycloheximide due to genetic mutation of Tas2r105.In addition,these mutant mice showed a loss of taste perception to quinine dihydrochloride,denatonium benzoate,and cucurbitacin B(CuB).Gnat3-mediated taste receptor and its signal pathway contribute to CuB perception.Conclusions:These findings implied that these mutant mice would be a valuable means to understand the biological functions of TAS2Rs in extraoral tissues and investigate bitter compound-induced responses mediated by these TAS2Rs in many extraoral tissues.

First report of the histopathological effect of electrocautery using on the urethral taste rosea during glans penis injury by incision in rabbits

Objective:Currently,electrocautery devices have frequently been used in penile surgical procedures.We hypothesized that electrocautery using during penile surgical procedures may harm the taste rosea and the dorsal nerve of the penis or clitoris.Methods:Eighteen young age male New Zealand rabbits were studied:five in the control(Group I,n=5),five in the penile surgery without using electrocautery(sham group,Group II,n=5),eight in the monopolar cautery(study group,Group III,n=8)groups under general anesthesia.The animals were followed for 3 weeks and sacrificed.Penile tissue—pudendal nerve root complexes and dorsal root ganglion of sacral 3 level were examined using stereological methods.The results were compared statistically.Results:The live and degenerated taste bud-like structures and degenerated neuron densities of pudendal ganglia(mean±standard deviation,n/mm^(3))were estimated as 198±24/mm^(3),4±1/mm^(3),and 5±1/mm^(3) in Group I;8±3/mm^(3),174±21/mm^(3),and 24±7/mm^(3) in Group II;and 21±5/mm^(3),137±14/mm^(3),and 95±12/mm^(3) in Group III,respectively.Neurodegeneration of taste buds and pudendal ganglia was significantly different between groups.Conclusion:Intact spinal cord and normal parasympathetic and thoracolumbar sympathetic networks are crucial for human sexual function.The present study indicates that the glans penis injury by using electrocautery may lead to pudendal ganglia degeneration.Iatrogenic damage to taste rosea and retrograde degeneration of the pudendal nerve may be the cause of sexual dysfunction responsible mechanism.

基于学习活动观的小学英语课堂TASTE教学模式探究

针对当前部分教师对于如何在小学英语课堂上落实学习活动观的困惑,文章通过大量案例研究提炼出一种基于学习活动观的TASTE教学模式。TASTE教学倡导教师基于单元整体视域,根据单元主题与单元目标,确立课时目标,以目标为导向设计连续性话题,并以连续性话题为支点,建构以探究答案、共享表现、真实表达为主要内容的活动流程,从而在课堂上落实学习理解、应用实践、迁移创新等三类活动。

魏福良教授治疗失眠症经验举隅

文章对魏福良教授治疗失眠症的经验进行了总结。失眠症为中医临床常见病,安徽省名老中医魏福良主任医师认为其诊治需从“五脏藏神”理论着手,诊脉查舌,辨证论治。魏师精研针、灸、药结合之道,用针本神,以脏腑辨证为本,精研刺灸之法,脏腑经络并治,令阴平阳秘;针药同施,内外并治,脏腑气血阴阳调和而神自安。

非定常流Weis-Fogh机构在零航速减摇中的应用

由于Weis-Fogh机构的仿生机构可以在零航速下产生升力,因此可以用来进行零航速减摇.基于势流理论建立的Weis-Fogh机构升力模型忽略了翼缘的分离涡对翼的作用,所以不能更好地模拟实际流场.因此基于点涡模型建立Weis-Fogh机构升力模型,并对Weis-Fogh机构张开时所产生的升力进行了数值计算.通过对有分离涡的Weis-Fogh机构升力和没有分离涡的Weis-Fogh机构升力之间的对比,发现前者产生的升力远大于后者.最后同实验数据进行了比较,证明该点涡升力模型可以更好地模拟翼上产生的升力.

Variation Characteristics of Main Climate Factors in the Upstream of Wei River in Recent 39 Years

Wei River is an important river which affects the industrial and agricultural production,people's life in Guanzhong district of Shaanxi and the east of Gansu.To study the variation characteristics of main climate factors in recent 39 years in the upstream of Wei River,we analyzed the variation characteristics of climate factors by using the data in 11 meteorological stations in the upstream basin of Wei River during 1971-2009.The results showed that the precipitation presented the decline trend in the basin,and the temperature rose in 0.3 ℃/10 a trend.The temperature increase trend was 0.4 ℃/10 a in winter,spring and wasn't obvious in summer,autumn.The potential evapotranspiration presented the yearly increase trend in recent years.The precipitation decreased,and the temperature rose.Moreover,the potential evapotranspiration strengthened.It wasn't favorable for the healthy run of ecological system in the upstream,downstream basins and aggravated the shortage degree of water resources.

基于WEI+的流域水资源短缺分析

为了分析我国各流域的水资源短缺现状,引入欧盟开发改进的水资源开发利用系数(Water Exploitation Index Plus,简称WEI+),以全国10个水资源一级区作为研究对象,计算2003—2012年各水资源一级区的水资源短缺情况。结果表明:(1)WEI+指数最小的是西南诸河区,其均值为1.9%;WEI+指数最大的是海河区,其均值为130%;且南方4区的WEI+指数均小于北方6区,说明我国北方比南方面临更为严重的水资源短缺问题。(2)南方4区的WEI+指数在2003—2012年间波动不大,而北方6区的WEI+指数波动剧烈;大部分地区的WEI+指数均呈现出下降趋势,这说明区域的水资源短缺情况有所缓解。(3)WEI+指数与流域水利水电开发利用程度在空间上的分布规律基本类似,这说明WEI+指数能够有效反映区域的水资源短缺情况。

有间隙翼片的Weis-Fogh效应

Weis-Fogh效应是一种昆虫产生大升力的机制,在它的实际应用中两个翼片往往不可能完全合拢,而是保留一定的间隙。翼片的间隙导致环量的减小。讨论了间隙对环量的影响和环量对间隙的敏感度,并给出比较适当的间隙的建议。

响应面法优化蚕蛹发酵工艺及其产物呈味特性研究

为优化建立蚕蛹发酵工艺,探索其发酵产物呈味特性,本文研究了不同菌种、接种量、发酵温度、发酵时间对蚕蛹发酵产氨基酸态氮含量的影响,在单因素实验的基础上,采用响应面法对蚕蛹发酵工艺进行优化,并对比分析发酵前后呈味物质与滋味的变化。结果表明:清酒乳杆菌接种量1.0%、发酵温度32℃、发酵时间10 d是最佳发酵工艺,此时氨基酸态氮含量达0.95±0.02 g/100 g,与预测值相近。与未发酵蚕蛹相比,发酵蚕蛹的游离氨基酸、核苷酸和有机酸含量均显著升高(P<0.05),分别为52.19±0.11、1.01±0.03、65.54±1.61 mg/g。呈鲜味的天冬氨酸、谷氨酸、鸟苷酸、腺苷酸和琥珀酸的TAV值均大于1,特别是谷氨酸和琥珀酸,TAV值高达20.06、138.47,是发酵蚕蛹中鲜味的重要贡献者;蚕蛹发酵后的味精当量达74.44 g MSG/100 g,是发酵前的6.74倍。本研究表明,蚕蛹发酵可产鲜味物质,且风味良好,为蚕蛹的开发利用和鲜味物质的制备提供了新的思路。

长吻Wei幼鱼的赖氨酸需要量

本文通过以添加结晶氨基酸的半精制饲料饲喂长吻Ｗｅｉ（ＬｅｉｏｃａｓｓｉｓｌｏｇｎｉｒｏｓｔｒｉｓＧｕｎｔｈｅｒ）幼鱼的生长试验来确定春赖氨基酸需要量，试验饲料由鱼粉，玉米蛋白，糊精，明胶等组成，通过添加游离氨基酸达饲料中分别含赖氨酸国１．６４，２．０４，２．４４，２．８４和３．２４％五个水平，结果得出：长吻Ｗｅｉ幼鱼最大生长时对饲料中的赖氨酸的需要量为２．５７％，占饲料蛋白的６．５４％。

基于Weis-Fogh机构的零航速减摇鳍升力特性研究

为了克服传统减摇鳍只能在有航速情况下进行减摇的缺点,该文提出了一种基于Weis-Fogh机构的零航速减摇鳍.通过对Weis-Fogh机构原理与流体特性的深入研究,从理论上推导出平板翼的升力表达式,确定了升力与旋转角速度及角加速度之间的函数关系.在Matlab/Simulink环境下,建立了平板翼的升力模型,完成了平板翼在各种运动规律下的升力仿真实验.仿真结果证明,这种新型的减摇鳍能够在零航速下瞬间产生巨大升力,通过控制翼的旋转角速度及角加速度能够控制升力的大小及建立的时间,验证了采用Weis-Fogh机构设计零航速减摇鳍的可行性.

叶栅型Weis-Fogh水翼推进机构流体动力性能研究

本文建立了叶栅型Weis-Fogh水翼推进机构的物理模型和数学模型，利用保角变换理论和奇异积分理论推导出流体动力解析计算公式。以点涡代替前缘分离涡，对单翼叶栅Weis-Fogh机构建立了便于理论分析的点涡模型。本文理论分析和计算表明，流体动力随栅距的减小而增大；分离涡增大流体动力；力矩的实例计算数据与已有的试验吻合。

基于Weis-Fogh机构的零航速减摇鳍升力模型的研究

随着减摇技术的发展,出现了一种可以使用减摇鳍在零航速下进行减摇的新方法,这种方法使减摇鳍既可以在零航速下进行减摇也可以在中高航速下满足减摇的需要。文章结合国外的相关文献,对零航速下减摇鳍的工作方式和产生的升力进行了相关的研究。并根据Weis-Fogh机构流体动力学知识对升力进行了分析,建立了零航速下减摇鳍的升力模型,根据模型进行了升力仿真研究。

利用WeiPHP开源框架实现微信图书馆

调查分析当前图书馆移动服务,包括手机图书馆和微信服务的现状,分析目前移动服务存在的不足之处。探讨了用开源框架Wei PHP开发微信图书馆的优势,在分析图书馆业务需求的基础上,提出了技术思路,以南京大学微信图书馆的测试为例说明了实践过程和应用效果。