In-silico Prediction of the Sweetness of Aspartame Analogues from QSPR Analysis

The extensive utilization of the low-energy dipeptide sweetener aspartame in foods leads to various studies on searching for new sweeteners in series. However, the real mechanistic cause of their sweetness power is still not completely known owing to their complex interactions with human sweet receptor, which may be different from that of other sweeteners to some extent. In this contribution, predictive quantitative structure-property relationship(QSPR) models have been developed for diverse aspartame analogues using Materials Studio 5.0 software. The optimal QSPR model(r2 = 0.913, r2 CV = 0.881 and r2 pred = 0.730) constructed by the genetic function approximation method has been validated by the tests of cross validation, randomization, external prediction and other statistical criteria, which shows that their sweetness power is mainly governed by their electrotopological-state indices(SssCH and SsNH), spatial descriptors(Shadow length: LX, ellipsoidal volume and Connolly surface occupied volume) and topological descriptors(Chi(3): cluster and Chi(0)(valence modified)), which partially supports both multipoint attachment theory proposed by Nofre and Tinti et al. and B-X theory proposed by Kier et al.. Present exploited results provide the key structural features for the sweetness power of aspartame analogues, supplement the mechanistic understanding of the sweet perception, and would be also helpful for the design of potent sweetener analogs prior to their synthesis.

Correlation Study on Sweetness of Amino Acid with Different Configurations and Quantum Chemical Parameters

Quantum chemical parameters of 10 amino acids with D- and L-configurations were firstly calculated with semi-empirical AM1 method. Furthermore, the relationship between molecular structures of D-, L-amino acids and their sweetness were observed. The results show that upon different configurations of amino acids, the sweetness is relative with their formation heat, dipole moment, energy gap of frontier orbital and other parameters. The formation heats of the same amino acids possessing D- and L-configurations are different except glycine. The algebraic value of D-amino acid is generally larger than that of corresponding L-configuration with only one except of tyrosine. The dipole moment of D-amino acid is generally larger than that of corresponding L-amino acid except tyrosine and lysine. The lowest unoccupied orbital energy （ELUMO） of D-amino acid is higher than that of corresponding L-configuration except phenylalanine. △E of D-amino acid is larger than that of L-amino acid except histidine, phenylalanine and lysine. The larger gap will have advantage for its matching with frontier orbital energy of human protein acceptor, which strengthens the interaction between D-amino acid and sweet taste acceptor. Besides, the changing rules of these parameters are generally identical.

Temporal Sequence of Sweetness Perception in Fruit-Flavored Tea: A Descriptive Report on the Influence of Sucrose Concentrations on the Sensation

The goals of this study were to examine, using the temporal dominance of sensations (TDS) method, the effects of 1) the sucrose concentration on the temporal sequence of sweetness perception in four fruit-flavored (lemon, peach, strawberry, and vanilla) teas with 0.05, 0.15, and 0.25 M sucrose;and 2) participants’ sex on this temporal sequence. Twenty-four healthy young adults were assigned to female (n = 12) and male (n = 12) groups. Both groups evaluated five sensory attributes in 12 samples (four fruit-flavored teas, each with three sucrose concentrations). As in our preceding study [1], two sensations, sweetness and fruitiness, were dominant after ingesting the 12 teas in both groups, but the temporal sequence of sweetness perception differed between the two groups. On average, the male group reported the first appearance of sweetness earlier in the samples with 0.05 M sucrose compared with the female group, with the samples containing 0.15 and 0.25 M sucrose. The average durations of the sweetness sensation were different between the male and female groups as well as among the sucrose concentrations and the four flavors tested.

Low-heat High Sweetness Protein Glycosidase

The protein glycosidase APM is a seet agent produced from amino acid necessary to the body. With a sweetness 200 times more than that of the refined sugar, this product has been confirmed as an A (1) Class low heat, high sweetness agent by specialists of JECFA of the United Nations. A series of toxicology tests undertaken by the United States, China and Japan as well as many other international institutions over past decades, have proven the

枸杞SWEET基因家族鉴定及其与可溶性糖含量关系

【目的】糖外排转运蛋白(sugars will eventually be exported transporters,SWEETs)在植物生长发育过程中发挥重要作用,解析SWEETs基因在枸杞果实发育过程中对糖积累作用,为进一步揭示SWEETs基因在枸杞果实发育过程中的作用提供参考。【方法】用生物信息学方法对枸杞SWEET基因(LbaSWEETs)进行全基因组鉴定,并用已发表的转录数据分析LbaSWEETs在果实发育时期的基因表达情况。【结果】枸杞SWEET基因家族共有37个成员,随机分布于10条染色体上,分别编码152~621个氨基酸,蛋白质分子质量为16.87~69.97 kD,等电点为4.96~9.86。亚细胞定位预测位于叶绿体或质膜,大多数含有7个跨膜螺旋。系统进化分析发现,37个LbaSWEETs蛋白可分为4个亚群,每个亚群的基因结构和保守基序组成相似。启动子元件分析表明:Lba-SWEETs基因启动子富含大量激素响应、逆境胁迫和生长发育响应元件。转录组数据和qRT-PCR分析表明:LbaSWEET9和LbaSWEET29基因表达量随果实成熟呈现显著增加。相关性分析结果表明,LbaSWEET9和LbaSWEET29基因表达量与果糖含量呈显著正相关。【结论】LbaSWEET9和LbaSWEET29基因是果糖积累的关键基因。

基于转录组信息的百合SWEET基因家族鉴定及表达特性分析

以东方百合品种‘西伯利亚’为试材,采用生物信息学方法,研究了百合SWEET基因家族成员编码蛋白的理化性质、二级结构、系统进化、保守结构域、Motif及基因表达模式,对百合SWEET基因家族成员进行鉴定,探究其在鳞茎发育过程中的作用,以期为该类基因生物学功能和百合地下茎生鳞茎发育机制的研究提供参考依据。结果表明:从转录组数据鉴定到了12个SWEET基因,所有家族成员都为稳定的疏水蛋白,且均含有MtN3_slv结构域,可划分为4个亚家族,不同成员在百合茎生鳞茎形成和进一步发育中差异表达。

中药辨证治疗Sweet综合征1例报道并文献复习

Sweet综合征又名急性发热性中性粒细胞增多性皮病,是一种与许多不同的基础疾病相关的皮肤病。其主要临床表现为发热、疼痛性红色斑块或结节,外周血白细胞和中性粒细胞增多,组织病理学特点为真皮中大量中性粒细胞浸润[1]。本病发病机制尚不明确,慢性感染和恶性肿瘤是最常见的发病诱因,临床表现差异很大,容易误诊,组织病理是诊断Sweet综合征的可靠依据。现报道1例以中药方剂内服为主治疗有干燥综合征基础合并Sweet综合征患者的过程并进行文献复习。

联合化疗治疗原发性胃弥漫大B细胞淋巴瘤合并Sweet综合征1例并文献复习

非霍奇金淋巴瘤(non-Hodgkin lymphoma,NHL)是临床常见的肿瘤类型,临床表现多样,确诊依赖组织活检,根据病灶起源可以分为结内和结外淋巴瘤。原发性胃肠淋巴瘤是结外淋巴瘤的常见部位,可以累及胃、小肠、结肠等,其中约50%~60%发生在胃部,病理类型以黏膜相关淋巴组织淋巴瘤和弥漫大B细胞淋巴瘤(diffuse large B-cell lymphoma,DLBCL)为主[1~3]。

滇水金凤花蜜相关SWEET7和SWEET16的克隆及表达分析

植物SWEET(Sugars will eventually be exported transporter)基因家族是一类重要的糖转运蛋白,参与开花植物的花蜜合成。本研究以野生型和突变型滇水金凤(Impatiens uliginosa)为材料,基于课题组前期的花距转录组数据,通过筛选和RT-PCR技术克隆得到花蜜相关基因SWEET7和SWEET16,分别命名为IuSWEET7和IuSWEET16,其cDNA分别为741 bp和903 bp,分别编码246和300个氨基酸。生物信息学分析表明:IuSWEET7为疏水性不稳定蛋白,IuSWEET16为疏水性稳定蛋白,二者均含有2个典型的MtN3/saliv保守结构域;IuSWEET7和IuSWEET16基因的氨基酸序列与杜鹃花(KAG5539487.1)、一串红(XP_042052415.1)等植物同源序列的相似性均在54.15%~71.48%;系统进化分析表明,IuSWEET7和IuSWEET16处于两个不同分支。qRT-PCR分析表明两个基因在野生型和突变型滇水金凤花距的3个时期中均有表达,且在不同部位中表达模式不同。其中IuSWEET7基因在野生型滇水金凤中其表达量从花苞期至盛花期逐渐上升;在突变型2距和3距中其表达量从花苞期至盛花期先上升后下降,且在始花期表达量最高;而IuSWEET16基因在野生型和突变型3距中其表达量从花苞期至盛花期均逐渐上升,但在突变型2距中其表达量从花苞期至盛花期先上升后下降,也在始花期时达到最高。

植物SWEET基因及其糖转运功能研究进展

SWEET(sugars will eventually be exported transporter)是一类介导蔗糖或己糖通过顺浓度梯度被动扩散跨细胞膜转运的新型糖转运蛋白。植物SWEET蛋白包括7个跨膜结构域,其中包含2个MtN3/Saliva结构域,可分为4个进化分支。SWEET转运蛋白在多种生理和生化过程中发挥着关键作用,包括韧皮部装载、激素运输、营养和生殖生长等。结合当前SWEET转运蛋白的研究进展,重点总结了SWEET的发现、蛋白结构及其在糖转运中的生物学功能,指出目前植物SWEET基因研究面临的问题,并对未来SWEET蛋白的研究重点进行了展望:1)探究SWEET蛋白的底物识别机制;2)挖掘提高作物产量和品质的关键SWEET基因;3)利用SWEET基因编辑和磷酸化等策略改良作物产量和品质。

Sweet综合征口腔黏膜表现1例报道及文献回顾

目的探讨Sweet综合征的口腔黏膜病损表现,为临床早发现并正确诊断该病提供参考。方法报道1例60岁女性Sweet综合征患者的口腔黏膜病损表现,并结合相关文献对Sweet综合征进行分析。结果患者双下肢皮肤红斑伴口腔黏膜破溃疼痛3 d,患者皮损症状较轻,但口腔黏膜多发性大面积糜烂,疼痛明显,故首诊于口腔科。患者发病过程中伴有发烧,体温38.5℃;实验室检查示C反应蛋白升高(35.2 mg/L),血沉加快(77.00 mm/h);患者两侧膝盖及下肢可见散在分布红色斑块,轻度压痛,皮损组织病理学检查示:真皮全层见散在不成熟中性粒细胞聚集灶浸润。根据患者临床体征和实验室检查,皮损组织病理结果的镜下符合Sweet综合征的表现,诊断为Sweet综合征。给予患者1 mL复方倍他米松注射液肌肉注射仅1次;患者对糖皮质激素治疗效果反应良好;口腔采用复方氯己定溶液含漱,病损黏膜处重组牛碱性成纤维细胞生长因子溶液外用,3次/d,疗程为1周;用药4 d后复诊,体温恢复正常,口腔病损明显减轻;2周后复诊,小腿及膝盖处红斑几乎全部消退,口腔黏膜病损基本消失;半年后随访,结果显示皮损未复发;2年后随访,病情稳定,病损未见复发。回顾相关文献表明,Sweet综合征是一种少见的病因不明的炎性反应性皮病,临床上可分为3种类型:特发型、肿瘤相关型以及药物诱导型,男女患病比为1∶4,典型临床表现为急性出现的疼痛性红色斑块或结节,病损多位于四肢,常伴发热,外周血中性粒细胞数目增多,血沉加快,C反应蛋白阳性。系统应用糖皮质激素是本病最重要的治疗方法,大多数患者可在短期内改善皮损,但可能会存在潜在感染或停药后复发的情况。部分Sweet综合征患者可伴有口腔病损,但目前有关Sweet综合征在口腔黏膜表现的病例报道却很少,使得临床容易误诊。结论口腔黏膜病损可能为Sweet综合征的皮肤外表现,应综合考虑患者的全身情况,尽快完善皮肤活检以明确诊断,以免延误病情。

Sweet综合征的发病机制及治疗进展

Sweet综合征(Sweet syndrome, SS)是一种病因不明的炎症性嗜中性皮肤病,与感染、药物、肿瘤及自身免疫性疾病等相关。发病机制涉及中性粒细胞功能障碍、免疫失衡及遗传因素等。传统一线治疗首选系统应用糖皮质激素。近年来随着SS的研究取得一定进展,生物制剂及小分子靶向药物也有成功治疗SS的报道。本文就SS的发病机制及治疗进展作一综述。

油茶SWEET基因家族的全基因组鉴定及表达分析

【目的】挖掘参与油茶糖代谢及逆境响应的糖外排转运子(sugars will eventually be exported transporters,SWEETs)。【方法】利用生物信息学方法分析油茶SWEETs家族的基因结构、蛋白基序、染色体定位、共线性关系、启动子区顺式作用元件及上游调控因子等,并利用RT-qPCR分析CoSWEETs在不同时期、不同组织及不同逆境胁迫下的基因表达情况。【结果】从油茶中鉴定得到14个CoSWEETs基因,不均匀分布于10条染色体上,不同成员间内含子-外显子数目存在差异。根据系统进化关系,14个CoSWEETs可分为 4个分支,均具有1-2个MtN3 保守结构域,同一分支具有相似的基因结构和基序。根据启动子顺式作用元件和上游转录因子预测的分析结果,CoSWEETs启动子中含有多个与生长发育、植物激素和应激相关的调节元件,其表达可能受到ERF、DOF、BBR-BPC、MYB等转录因子的调控。RT-qPCR分析表明大部分CoSWEETs成员在果实和根中高表达,在种子中的表达水平与发育时期相关,并根据低温、高盐和干旱等非生物胁迫下CoSWEETs的表达模式挖掘出CoSWEET1、CoSWEET2、CoSWEET17等响应油茶低温、干旱或高盐胁迫的基因。【结论】CoSWEET基因的表达受到多种激素及转录因子调控,并在油茶种子发育与逆境胁迫响应中发挥重要作用。

溃疡性结肠炎合并Sweet综合征、玫瑰痤疮1例

患者女,43岁,因“面部反复红斑、丘疹,伴腹痛、腹泻”4年,复发1月,加重4d,于2021年4月第3次入我院。4年前患者因腹痛、腹泻伴面部红斑丘疹于我院住院,诊断“炎性肠病、面部激素依赖性皮炎”。1月前患者面部皮损、腹泻加重再次入院,结合病理检查结果诊断为“溃疡性结肠炎、玫瑰痤疮”。两次住院均使用激素、羟氯喹等治疗,好转后出院,但停药后病情反复。本次因面颈部、双上肢出现红色疼痛性斑块入院。结合病理检查结果诊断sweet综合征,予以甲泼尼龙40mg,皮损逐渐消退。

Development characteristics and controlling factors of fractures in lacustrine shale and their geological significance for evaluating shale oil sweet spots in the third member of the Shahejie Formation in the Qikou Sag, Bohai Bay Basin

Natural fractures are critical for shale oil and gas enrichment and development. Due to the extremely high heterogeneity of shale, the factors controlling the formation of internal fractures, especially horizontal fractures, remain controversial. In this study, we integrate thin section analysis and microcomputed tomography(CT) data from several lacustrine shale samples from the third member(Es3) of the Shahejie Formation, Qikou Sag, Bohai Bay Basin, to assess the fractures in detail. The goal is to reveal the development characteristics, controlling factors, and geological significance for evaluating sweet spots in a shale oil play. The fractures in the Es3contain high-angle structural and horizontal bed-parallel fractures that are mostly shear and extensional. Various factors influence fracture development,including lithofacies, mineral composition, organic matter content, and the number of laminae. Structural fractures occur predominantly in siltstone, whereas bed-parallel fractures are abundant in laminated shale and layered mudstone. A higher quartz content results in higher shale brittleness, causing fractures, whereas the transformation between clay minerals contributes to the development of bedparallel fractures. Excess pore pressure due to hydrocarbon generation and expulsion during thermal advance can cause the formation of bed-parallel fractures. The density of the bed-parallel and structural fractures increases with the lamina density, and the bed-parallel fractures are more sensitive to the number of laminae. The fractures are critical storage spaces and flow conduits and are indicative of sweet spots. The laminated shale in the Es3with a high organic matter content contains natural fractures and is an organic-rich, liquid-rich, self-sourced shale play. Conversely, the siltstone, massive mudstone, and argillaceous carbonate lithofacies contain lower amounts of organic matter and do not have bed-parallel fractures. However, good reservoirs can form in these areas when structural fractures are present and the source, and storage spaces are separated.

Protein glycation:a wolf in sweet sheep’s clothing behind neurodegeneration

At the beginning of the 16th century,Paracelsus coined the maxim:“the dose makes the poison”.This principle can be applied to all living organisms,including organs and cells.The brain and its glial and neuronal cells are no exception.Even small compounds that are essential for the life of brain cells can become truly toxic when overdosed.

Metabolic profiles and morphological characteristics of leaf tips among different sweet potato(Ipomoea batatas Lam.)varieties

Sweet potato leaf tips have high nutritional value,and exploring the differences in the metabolic profiles of leaf tips among different sweet potato varieties can provide information to improve their qualities.In this study,a UPLC-Q-Exactive Orbitrap/MS-based untargeted metabolomics method was used to evaluate the metabolites in leaf tips of 32 sweet potato varieties.Three varieties with distinct overall metabolic profiles(A01,A02,and A03),two varieties with distinct profiles of phenolic acids(A20 and A18),and three varieties with distinct profiles of flavonoids(A05,A12,and A16)were identified.In addition,a total of 163 and 29 differentially expressed metabolites correlated with the color and leaf shape of sweet potato leaf tips,respectively,were identified through morphological characterization.Group comparison analysis of the phenotypic traits and a metabolite-phenotypic trait correlation analysis indicated that the color differences of sweet potato leaf tips were markedly associated with flavonoids.Also,the level of polyphenols was correlated with the leaf shape of sweet potato leaf tips,with lobed leaf types having higher levels of polyphenols than the entire leaf types.The findings on the metabolic profiles and differentially expressed metabolites associated with the morphology of sweet potato leaf tips can provide useful information for breeding sweet potato varieties with higher nutritional value.

Invasion of fall armyworm led to the succession of maize pests in Southwest China

The invasive fall armyworm Spodoptera frugiperda(J.E.Smith)invaded Asia in 2018,colonizing the tropical and southern subtropical regions as well as migrating with the monsoons into Northeast Asia during spring and summer.This has resulted in widespread infestations,with significant impacts on maize production in various Asian countries.Previous studies have shown that the invasion of this pest can alter the species relationships of maize pests,but the actual impact on maize pest management is still unclear.This study investigated the changes in maize pest occurrence and pesticide use in the annual breeding areas of S.frugiperda in Yunnan Province and the Guangxi Zhuang Autonomous Region of China during 2017-2021,based on surveys and interviews with small farmers in maize production.The results showed that S.frugiperda has emerged as the dominant species among maize pests after invasion and colonization,replacing traditional pests such as Ostrinia furnacalis,Spodoptera litura,Agrotis ypsilon,and Rhopalosiphum maidis.The variety of pesticides used for maize pest control has changed from chlorpyrifos,lambda-cyhalothrin,and acetamiprid to emamectin benzoate-based pesticides with high effectiveness against S.frugiperda.Furthermore,the frequency of maize pest chemical applications has increased from an average of 5.88 to 7.21 times per season,with the amounts of pesticides used in summer and autumn maize being significantly higher than in winter and spring maize,thereby increasing application costs by more than 35%.The results of this study clarified the impact of S.frugiperda invasion on maize pest community succession and chemical pesticide use in tropical and south subtropical China,thereby providing a baseline for modifying the regional control strategies for maize pests after the invasion of this relatively new pest.

Highβ-sitosterol-D-glucoside content in sweet potato varieties and its anti-breast cancer potential through multiple metastasis-associated signals

β-Sitosterol-D-glucoside(β-SDG)is a phytosterol compound whose antitumor activity has been confirmed by previous studies.However,its suppression on breast cancer remains unclear.To that purpose,we isolatedβ-SDG from sweet potato and investigated the breast-cancer-inhibiting mechanism using proteomic analysis.The sweet potato species S6 with highβ-SDG content were chosen form 36 species andβ-SDG was isolated by HPLC.Afterwards,an in situ animal model of breast cancer was established,andβ-SDG significantly reduced the tumor volume of MCF-7 xenograft mice.Proteomic analysis of tumor tissues revealed that 127 of these proteins were upregulated and 80 were downregulated.Gene ontology and network analysis showed that regulatory proteins were mainly associated with epithelial-mesenchymal transition(EMT),myogenesis,cholesterol homeostasis,oxidative phosphorylation and reactive oxygen pathways,while Vimentin,NDUF,VDAC1,PPP2CA and SNx9 were the most significant 5 node degree genes.Meanwhile,in vitro and in vivo results showed that the protein expression of PPP2CA and Vimentin,which are markers of EMT,were involved in breast cancer cell metastasis and could be reversed byβ-SDG.This work highlightsβ-SDG as a bioactive compound in sweet potato and the potential therapeutic effect ofβ-SDG for the treatment of breast cancer by inhibiting metastasis.

Key geological factors governing sweet spots in the Wufeng-Longmaxi shales of the Sichuan Basin,China

Production performance of the Wufeng-Longmaxi shales varies significantly among Fuling,Weirong,and Wulong fields in the Sichuan Basin.Total organic carbon(TOC)content,mineralogy,and organic matter(OM)pore characteristics are investigated to identify key factors governing sweet spots.Siliceous shales with good preservation conditions in the Fuling Field exhibit large thickness,high TOC content and thin-section porosity(TSP),and well-developed OM macropores,thus high initial production and estimated ultimate recovery(EUR).Thin carbonate-containing siliceous shales with good preservation conditions in the Weirong Field feature medium-to-high TOC and well-developed OM macropores but low TSP,leading to high initial production but low EUR.Siliceous shales with poor preservation conditions in the Wulong Field are characterized by large thickness,high TOC,low TSP and poorly-developed OM macropores,causing low initial production and EUR.Both sedimentary and preservation conditions are intrinsic decisive factors of sweet spots,as they control the mineral composition,TOC,and OM macropore development.Deep-water shales in transgressive systems tracts(TSTs)exhibit better-developed OM macropores and greater TOC compared to highstand systems tracts(HSTs).OM macropores are most prevalent in siliceous shales,followed by carbonate-containing siliceous shales and then argillaceous shales.Furthermore,good preservation conditions are conducive to retain OM macropores with low pore aspect ratio(PAR).Comparison among the three fields shows that high-TOC silicious shales with good preservation conditions are the highest in TSP and EUR.Therefore,organic richness,lithofacies,and preservation conditions are the major factors which determine OM pore development,governing the sweet spots of the Wufeng-Longmaxi shales.