disaccharides

二糖
  • 文章类型: Journal Article
    在小鼠阿尔茨海默病的实验模型中,口服海藻糖二糖可减少通过小胶质细胞活化标志物Iba1表达水平评估的神经炎症,并影响中性粒细胞脱颗粒活性。揭示了与血浆中白细胞弹性蛋白酶活性降低相关的4%海藻糖溶液的潜在抗炎作用。
    In an experimental model of Alzheimer\'s disease in mice, oral administration of trehalose disaccharide reduces neuroinflammation assessed by the expression level of microglia activation marker Iba1 and affects the neutrophil degranulation activity. A potential anti-inflammatory effect of 4% trehalose solution associated with a decrease in the activity of leukocyte elastase in plasma was revealed.
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  • 文章类型: Journal Article
    这项研究的目的是在从移植中丢弃的七个心脏移植物中使用Celsior溶液在现实的临床冷藏条件下提供对高能磷酸盐化合物浓度动态的了解。七个当地捐赠者的心(三个男性,四位女性,年龄37±17岁,高度175±5厘米,体重75±9kg)最初考虑移植并最终丢弃,在临床磁共振成像扫描仪中接受磁共振波谱观察至少9小时。在整个检查过程中,移植物在4°C下保持在无菌容器中。因此,磷酸肌酸(PCr),三磷酸腺苷(ATP),以30分钟的间隔无损地记录无机磷酸盐(Pi)和细胞内pH。随着缺血时间Ti,浓度比在PCr/ATP=1.68-0.0028·Tis时降低,Pi/ATP=1.38+0.0029·Tis,细胞内pH为7.43-0.0012·Tis。ATP浓度保持稳定至少9小时,只要可检测到磷酸肌酸,则不会降低。酸中毒仍然中等。除了检索时评估的标准参数外,磁共振波谱可以在移植前评估心脏移植物的代谢状态。这些结果显示HEPC代谢物在冷藏期间如何耗尽。尽管许多参数决定了冷藏过程中的移植物质量,HEPC和细胞内pH的动力学可能有助于制定旨在延长缺血时间的策略。
    The aim of this study was to provide insight into high-energy phosphate compound concentration dynamics under realistic clinical cold-storage conditions using the Celsior solution in seven heart grafts discarded from transplantation. The hearts of seven local donors (three males, four females, age 37 ± 17 years, height 175 ± 5 cm, weight 75 ± 9 kg) initially considered for transplantation and eventually discarded were submitted to a Magnetic Resonance Spectroscopy observation in a clinical Magnetic Resonance Imaging scanner over at least 9 h. The grafts remained in their sterile container at 4°C during the entire examination. Hence, Phosphocreatine (PCr), adenosine triphosphate (ATP), inorganic phosphate (Pi) and intracellular pH were recorded non-destructively at a 30-minute interval. With the ischemic time Ti, the concentration ratios decreased at PCr/ATP = 1.68-0.0028·Tis, Pi/ATP = 1.38 + 0.0029·Tis, and intracellular pH at 7.43-0.0012·Tis. ATP concentration remained stable for at least 9 h and did not decrease as long as phosphocreatine was detectable. Acidosis remained moderate. In addition to the standard parameters assessed at the time of retrieval, Magnetic Resonance Spectroscopy can provide an assesment of the metabolic status of heart grafts before transplantation. These results show how HEPC metabolites deplete during cold storage. Although many parameters determine graft quality during cold storage, the dynamics of HEPC and intracellular pH may be helpful in the development of strategies aiming at extending the ischemic time.
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  • 文章类型: Journal Article
    碳水化合物具有基于其结构的各种生物功能。然而,碳水化合物的组成和糖苷键连接和构型对其表征提出了挑战。此外,异构体特征有助于分子内氢键的形成,影响碳水化合物的灵活性和动力学。氢/氘交换质谱(HDX-MS)通过监测HDX后不同时间长度的氘标记来分析蛋白质动力学。电喷雾电离(in-ESI)HDX-MS已用于快速标记溶剂化的碳水化合物,在ESI液滴去溶剂化过程中发生标记。因此,HDX标记时间可以通过改变喷雾溶剂电导率来改变,这改变了ESI液滴的初始大小及其产生的寿命。这里,我们利用in-ESIHDX-MS来表征具有不同单糖组成和糖苷键连接和构型的九种异构二糖。我们比较了异构体在各个电导率下的相对D吸收,或HDX标记时间,以及在多个电导率下与标记相关的趋势。有趣的是,相对D摄取趋势与影响二糖柔韧性的异构特征相关,包括分子内氢键的形成。在研究的异构特征中,观察到与(1-3)连接的二糖的连接对相对D-摄取具有显著影响,与其他连接相比,随着电导率的变化,相对D-摄取具有更大的变化。总的来说,这项研究说明了如何应用in-ESIHDX-MS在结构上表征具有不同异构特征的二糖。此外,这项工作表明,in-ESIHDX-MS可用于监测具有快速交换官能团的溶剂化分子的动力学。
    Carbohydrates have various biological functions that are based on their structures. However, the composition and the glycosidic-bond linkage and configuration of carbohydrates present challenges for their characterization. Furthermore, isomeric features contribute to the formation of intramolecular hydrogen bonds, which influence the flexibility and dynamics of carbohydrates. Hydrogen/deuterium exchange-mass spectrometry (HDX-MS) enables the analysis of protein dynamics by monitoring deuterium labeling after HDX for different lengths of time. In-electrospray ionization (in-ESI) HDX-MS has been used to rapidly label solvated carbohydrates with labeling occurring during desolvation of ESI droplets. Therefore, HDX-labeling times can be altered by changing the spray-solvent conductivity, which changes the initial size of ESI droplets and their resulting lifetimes. Here, we utilize in-ESI HDX-MS to characterize nine isomeric disaccharides with different monosaccharide compositions and glycosidic-bond linkages and configurations. We compared both the relative D-uptake of isomers at individual conductivities, or HDX-labeling times, and the trends associated with labeling at multiple conductivities. Interestingly, the relative D-uptake trends were correlated to isomeric features that affect disaccharide flexibility, including formation of intramolecular hydrogen bonds. Among the isomeric features studied, linkage was observed to have a significant influence on relative D-uptake with (1-3)-linked disaccharides having more change in relative D-uptake with changing conductivity compared to other linkages. Overall, this research illustrates how in-ESI HDX-MS can be applied to structurally characterize disaccharides with distinct isomeric features. Furthermore, this work shows that in-ESI HDX-MS can be used to monitor the dynamics of solvated molecules with rapidly exchanging functional groups.
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  • 文章类型: Journal Article
    子宫内膜异位症是一种雌激素依赖性慢性疾病,其特征是子宫外存在子宫内膜样组织,通常与症状有关。如痛经,排尿困难,Dyschezia,慢性盆腔疼痛,和不孕症。此外,诊断为子宫内膜异位症的女性可以报告胃肠道症状,包括腹胀,便秘或腹泻,腹部痉挛,这可能与肠易激综合征有关,并可能导致子宫内膜异位症最初误诊为肠易激综合征。治疗通常包括激素治疗,疼痛管理,手术,和/或不孕情况下的辅助生殖技术。尽管如此,这些治疗方法可能不足以缓解症状或可能具有不可接受的副作用,导致不遵守。因此,女性经常采用自我管理策略,包括饮食干预。经常建议在社交媒体和患者论坛上作为管理子宫内膜异位症相关症状的工具之一的饮食是无麸质饮食。尽管无麸质饮食已被证明可有效控制非乳糜泻小麦敏感性或乳糜泻,其在子宫内膜异位症中的有效性仍不确定。护士健康研究II发现,麸质摄入不太可能是子宫内膜异位症病因和症状学的重要因素。据我们所知,关于无麸质饮食对子宫内膜异位症疗效的最常引用和唯一发表的干预研究有几个重要的限制因素,包括没有对照组。此外,麸质消费极易受到安慰剂效应和nocebo效应的影响,女性在消除麸质后可能会出现症状缓解,并在再次食用麸质后恢复症状,仅仅因为他们认为面筋对他们有害。尽管体重指数与子宫内膜异位症之间存在负相关,但无麸质饮食与增加的体重指数之间存在负相关,这是一个协会,没有因果关系被证明。此外,应考虑其他因素。值得注意的是,无麸质饮食是昂贵的,可用性有限,对生活质量有显著影响。此外,没有适当的饮食指导,它可能会对胃肠道微生物组产生不利影响。因此,关于使用无麸质饮食治疗子宫内膜异位症相关症状的科学依据建议目前尚不可用,并且不鼓励无麸质饮食,除非有非乳糜泻小麦敏感性或乳糜泻的额外诊断。
    Endometriosis is an estrogen-dependent chronic disease characterized by the presence of endometriumlike tissue outside the uterus and is often associated with symptoms, such as dysmenorrhea, dysuria, dyschezia, chronic pelvic pain, and infertility. Moreover, women diagnosed with endometriosis can report gastrointestinal symptoms, including bloating, constipation or diarrhea, and abdominal cramping, which can be associated with irritable bowel syndrome and can result in the misdiagnosis of endometriosis as irritable bowel syndrome at first. Treatment usually involves hormonal therapy, pain management, surgery, and/or assisted reproductive techniques in case of infertility. Nonetheless, these treatment methods can be insufficient for alleviating symptoms or can have unacceptable side effects, leading to noncompliance. Therefore, women often apply self-management strategies, including dietary interventions. One of the diets frequently suggested as a tool to manage endometriosis-related symptoms on social media and patient forums is a gluten-free diet. Although a gluten-free diet has been proven effective in managing nonceliac wheat sensitivity or celiac disease, its effectiveness in endometriosis remains uncertain. The Nurses\' Health Study II found it unlikely that gluten intake was a strong factor in endometriosis etiology and symptomatology. To the best of our knowledge, the most frequently cited and sole published intervention study on the efficacy of a gluten-free diet for endometriosis has several important limiting factors, including the absence of a control group. In addition, gluten consumption is highly susceptible to a placebo effect and a nocebo effect, where women might experience symptom relief after eliminating gluten and return of symptoms after they consume gluten again, solely because they believe that gluten is bad for them. Despite the inverse association between body mass index and endometriosis and between a gluten-free diet and increased body mass index, this is an association, and no causality was proven. In addition, other factors should be taken into consideration. Of note, a gluten-free diet is expensive, has limited availability, and has a significant effect on quality of life. Moreover, without proper dietary guidance, it may adversely affect the gastrointestinal microbiome. Therefore, scientifically substantiated advice regarding the use of a gluten-free diet for endometriosis-related symptoms is currently not available, and a gluten-free diet should be discouraged unless there is an additional diagnosis of nonceliac wheat sensitivity or celiac disease.
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  • 文章类型: Journal Article
    已知类芽孢杆菌属内的细菌分泌能够分解植物细胞壁多糖的多种酶。我们研究了木聚糖类芽孢杆菌的细胞外木聚糖分解活性,并检查了在越来越复杂的基于碳水化合物的碳源上生长时分泌的蛋白质的完整范围。包括麦麸,甘蔗秸秆,山毛鱼木聚糖和蔗糖,作为控制。我们的数据表明,分泌蛋白质的相对丰度随所用碳源而变化。来自麦麸(WB)或甘蔗秸秆(SCR)培养物的细胞外酶提取物具有最高的木聚糖分解活性,与碳水化合物活性酶(CAZymes)的最大代表相吻合。使用WB放大到台式生物反应器导致生产率和总体积细胞外木聚糖酶活性的显着提高。通过冷冻干燥进一步浓缩。酶提取物在不同来源的木聚糖以及通过碱挤压(SCRE)预处理的甘蔗秸秆的解构中是有效的,产生木二糖和木糖,作为初级产品。通过用重组GH43β-木糖苷酶(EcXyl43)和GH62α-L-阿拉伯呋喃糖苷酶(CsAbf62A)补充酶提取物,可以提高从SCRE释放的木糖的总产量,代表性不足的两项活动。总的来说,我们发现木聚糖胞外酶提取物,补充特定的酶活性,是在木质纤维素生物质中靶向木聚糖的有效方法。
    Bacteria within the Paenibacillus genus are known to secrete a diverse array of enzymes capable of breaking down plant cell wall polysaccharides. We studied the extracellular xylanolytic activity of Paenibacillus xylanivorans and examined the complete range of secreted proteins when grown on carbohydrate-based carbon sources of increasing complexity, including wheat bran, sugar cane straw, beechwood xylan and sucrose, as control. Our data showed that the relative abundances of secreted proteins varied depending on the carbon source used. Extracellular enzymatic extracts from wheat bran (WB) or sugar cane straw (SCR) cultures had the highest xylanolytic activity, coincidently with the largest representation of carbohydrate active enzymes (CAZymes). Scaling-up to a benchtop bioreactor using WB resulted in a significant enhancement in productivity and in the overall volumetric extracellular xylanase activity, that was further concentrated by freeze-drying. The enzymatic extract was efficient in the deconstruction of xylans from different sources as well as sugar cane straw pretreated by alkali extrusion (SCRe), resulting in xylobiose and xylose, as primary products. The overall yield of xylose released from SCRe was improved by supplementing the enzymatic extract with a recombinant GH43 β-xylosidase (EcXyl43) and a GH62 α-L-arabinofuranosidase (CsAbf62A), two activities that were under-represented. Overall, we showed that the extracellular enzymatic extract from P. xylanivorans, supplemented with specific enzymatic activities, is an effective approach for targeting xylan within lignocellulosic biomass.
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  • 文章类型: Journal Article
    背景:六味地黄丸是一种具有多种抗癌特性的著名中药。中国有50多家制药商生产六味地黄丸,全世界每天都有数百万人口服。六味地黄丸中的D-glucaro-1,4-内酯(1,4-GL)定量为约12.0mg/g,是其主要生物活性成分,可在体内抑制β-葡萄糖醛酸苷酶的活性。1,4-GL可以预防和有效抑制各种类型的癌症。然而,其确切的作用机制仍然未知。这项研究将证明六味地黄丸对癌症的传统用法是合理的。
    目标:1,4-GL,来自六味地黄丸的生物活性成分,著名的中药,可以延缓二乙基亚硝胺(DEN)诱导的大鼠肝细胞癌(HCC)的进展。支撑这种效果的机制,然而,仍然知之甚少。
    方法:用或不用1,4-GL(40.0mg/kg)治疗健康和HCC大鼠,并采用基于1HNMR的代谢组学分析。通过UPLC-MS/MS定量测定尿酸途径中的10种代谢产物。黄嘌呤脱氢酶(XDH)的表达,SLC2A9mRNA,使用RT-qPCR和Western印迹测定SLC2A9蛋白。体外验证了1,4-GL对HCC-LM3细胞的作用。ROS活性的改变,在1,4-GL处理后脂多糖(LPS)诱导的NCTC-1469细胞中观察到SLC2A9和XDH基因水平。
    结果:1,4-GL干预后,改善病理形态学,肝癌大鼠肝脏病变观察到血清AFP水平恢复,AST,ALP,γ-GGT和费希尔比。肝脏代谢组学显示,肝癌大鼠的1,4-GL可显著调节肝脏代谢。尿酸,通过UPLC-MS/MS定量黄嘌呤和次黄嘌呤水平,发现在HCC大鼠中1,4-GL治疗后几乎恢复到对照水平。黄嘌呤氧化酶活性的变化,XDHmRNA表达,SLC2A9mRNA和蛋白表达也发生逆转。LM3HCC细胞中的1,4-GL处理与体内结果一致。此外,氧化应激指标,如T-SOD,GSH,用1,4-GL处理的HCC大鼠血清和肝脏中的CAT和MDA均得到改善。体外,观察到1,4-GL降低了NCTC-1469细胞中脂多糖诱导的ROS水平,增强了SLC2A9的mRNA和蛋白表达,并降低了XDH的mRNA水平。
    结论:由于尿酸产生下调和SLC2A9表达上调,1,4-GL通过降低尿酸和ROS水平对DEN诱导的HCC具有保护作用。1,4-GL可能代表一种新的治疗方法,通过靶向尿酸-ROS途径改善HCC的恢复。
    BACKGROUND: Liuwei dihuang pills is a famous Traditional Chinese Medicine with various anti-cancer properties. Over 50 pharmaceutical manufacturers produce Liuwei dihuang pills in China and an estimated millions of people around the world orally take it every day. D-glucaro-1,4-lactone (1,4-GL) was quantified to be about 12.0 mg/g in Liuwei dihuang pills and a primary bioactive component of it inhibiting the activity of β-glucuronidase in vivo. 1,4-GL can prevent and effectively inhibit various types of cancer. However, its exact mechanism of action remains unknown. The study would justify the traditional usage of Liuwei dihuang pills against cancers.
    OBJECTIVE: 1,4-GL, a bioactive ingredient derived from Liuwei dihuang pills, a famous Traditional Chinese Medicine, could delay the progression of diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC) in rats. The mechanism underpinning the effect, however, remains poorly understood.
    METHODS: Healthy and HCC rats were treated with or without 1,4-GL (40.0 mg/kg) and 1HNMR-based metabonomic analysis was employed. 10 metabolites in uric acid pathway were quantitatively determined by UPLC-MS/MS. The expression of xanthine dehydrogenase (XDH), SLC2A9 mRNA, and SLC2A9 protein was determined using RT-qPCR and Western Blot. The effect of 1,4-GL on HCC-LM3 cells was verified in vitro. The alterations of ROS activity, SLC2A9 and XDH gene levels were observed in NCTC-1469 cells induced by lipopolysaccharide (LPS) after 1,4-GL treatment.
    RESULTS: After the intervention of 1,4-GL, improved pathological morphology, liver lesions in HCC rats was observed with restored serum levels of AFP, AST, ALP, γ-GGT and Fisher\'s ratio. Hepatic metabonomics revealed that puring metabolism were significantly regulated by 1,4-GL in HCC rats. Uric acid, xanthine and hypoxanthine levels were quantified by UPLC-MS/MS and found to be nearly restored to control levels after 1,4-GL treatment in HCC rats. Changes in xanthine oxidase activity, XDH mRNA expression, and SLC2A9 mRNA and protein expression were also reversed. 1,4-GL treatment in LM3 HCC cells were consistent with the results in vivo. Furthermore, oxidative stress indicators such as T-SOD, GSH, CAT and MDA in serum and liver were improved after HCC rats treated with 1,4-GL. In vitro, 1,4-GL was observed to reduce lipopolysaccharide-induced ROS levels in NCTC-1469 cells with enhanced mRNA and protein expression of SLC2A9 and decreased mRNA level of XDH.
    CONCLUSIONS: The protective effects of 1,4-GL against DEN-induced HCC by reducing uric acid and ROS levels due to down-regulation of uric acid production and up-regulation of SLC2A9 expressions. 1,4-GL may represent a novel treatment that improves recovery from HCC by targeting uric acid-ROS pathway.
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  • 文章类型: Journal Article
    糖基转移酶是自然界形成糖苷键的关键生物催化剂。新的合成有用的糖基转移酶的发现和表征对于开发用于生产复杂碳水化合物和糖缀合物的有效酶促和化学酶促策略至关重要。在此,我们报告了多杀性巴氏杆菌PmNatB作为具有β1-3-半乳糖基转移酶和β1-3-N-乙酰半乳糖胺转移酶活性的双功能单催化结构域糖基转移酶的鉴定。它是一种新型的糖基转移酶,用于在一锅法多酶系统中构建结构多样的GalNAcβ3Galα/βOR和Galβ3GalNAcα/βOR二糖,并原位生成UDP糖。
    Glycosyltransferases are nature\'s key biocatalysts for the formation of glycosidic bonds. Discovery and characterization of new synthetically useful glycosyltransferases are critical for the development of efficient enzymatic and chemoenzymatic strategies for producing complex carbohydrates and glycoconjugates. Herein we report the identification of Pasteurella multocida PmNatB as a bifunctional single-catalytic-domain glycosyltransferase with both β1-3-galactosyltransferase and β1-3-N-acetylgalactosaminyltransferase activities. It is a novel glycosyltransferase for constructing structurally diverse GalNAcβ3Galα/βOR and Galβ3GalNAcα/βOR disaccharides in one-pot multienzyme systems with in situ generation of UDP-sugars.
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  • 文章类型: Journal Article
    Tamarixetin,一种天然的膳食黄酮,在缺血性中风的治疗中表现出巨大的潜力。本文旨在探讨tamarixetin对缺血性卒中的影响及其机制。用大脑中动脉阻塞再灌注(MCAO/R)模型评价他马利西汀对大鼠缺血性脑卒中的影响,通过评估神经功能缺损评分,脑含水量,大脑违规,和神经元损伤。促炎细胞因子的水平,NLRP3炎性体激活,活性氧(ROS)的产生,在MCAO/R大鼠和脂多糖刺激的细胞中测量烟酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶的表达。Tamarixetin的给药改善了MCAO/R大鼠的神经功能障碍和神经元丢失。此外,tamarixetin在体内和体外降低小胶质细胞过度活化和促炎细胞因子的表达。Tamarixetin减弱NF-κBp65磷酸化和启动子活性,减少NLRP3表达和caspase-1切割,并下调IL-1β和IL-18分泌以抑制NLRP3炎性体活化。超氧阴离子的水平,过氧化氢,ROS也被tamarixetin抑制。NADP+和NADPH水平的下调,gp91phox表达表明tamarixetin对NADPH氧化酶激活的改善作用。在用脂多糖处理的gp91phox敲低细胞中,tamarixetin对NADPH氧化酶激活的影响,ROS生成,NLRP3炎性体激活减弱。此外,tamarixetin在体外保护神经元免受小胶质细胞过度活化。我们的研究结果支持tamarixetin作为缺血性卒中的治疗药物的潜力,其作用机制涉及抑制NADPH氧化酶-NLRP3炎性体信号传导。
    Tamarixetin, a natural dietary flavone, exhibits remarkable potential for the treatment of ischemic stroke. The present article aimed to explore the impact of tamarixetin on ischemic stroke and elucidate the underlying mechanisms. Effects of tamarixetin on ischemic stroke were evaluated in rats using the middle cerebral artery occlusion and reperfusion (MCAO/R) model, by assessing the neurological deficit scores, brain water content, brain infraction, and neuronal damage. The levels of proinflammatory cytokines, NLRP3 inflammasome activation, reactive oxygen species (ROS) production, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase expression were measured in MCAO/R rats and lipopolysaccharide-stimulated cells. Tamarixetin administration improved the neurological dysfunction and neuronal loss in MCAO/R rats. In addition, tamarixetin reduced microglial hyperactivation and proinflammatory cytokines expression in vivo and in vitro. Tamarixetin attenuated NF-κB p65 phosphorylation and promoter activity, reduced NLRP3 expression and caspase-1 cleavage, and downregulated IL-1β and IL-18 secretions to suppress NLRP3 inflammasome activation. The levels of superoxide anion, hydrogen peroxide, and ROS were also suppressed by tamarixetin. The downregulation of NADP+ and NADPH levels, and gp91phox expression indicated the ameliorative effects of tamarixetin on NADPH oxidase activation. In the gp91phox knockdown cells treated with lipopolysaccharide, the effects of tamarixetin on NADPH oxidase activation, ROS generation, and NLRP3 inflammasome activation were diminished. Moreover, tamarixetin protects neurons against microglial hyperactivation in vitro. Our findings support the potential of tamarixetin as a therapeutic agent for ischemic stroke, and its mechanism of action involves the inhibition of NADPH oxidase-NLRP3 inflammasome signaling.
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  • 文章类型: Journal Article
    描述了将几丁质酶固定在磁性纳米颗粒(MNP)上,作为生物相容性载体,用于从几丁质废物中酶促生产二-N-乙酰基几丁糖。几丁质酶固定化是可行的,固定化产率为88.9±1.6%,活性保留为97.8±1.0%,与游离酶相比,固定化赋予了更好的热和储存稳定性。作为实际益处,与磁性纳米载体的连接使得在重复施用运行之后能够容易地回收酶,并且因此可持续地重复使用。在固定状态下,几丁质酶在16个反应循环后保留了显着的39.7±2.6%的起始活性。此外,固定化几丁质酶在一步反应中将虾壳和鱿鱼壳几丁质转化为二-N-乙酰基几丁糖方面比游离几丁质酶具有更高的催化活性。来自虾壳的纯化化合物的最终产率为37.0±1.2%,来自鱿鱼几丁质的最终产率为61.1±0.5%。总之,开发了一种有效的基于MNP的几丁质酶固定化系统,具有大规模生产的潜力。
    Described is chitinase immobilization on magnetic nanoparticles (MNPs) as biocompatible support for enzymatic production of di-N-acetyl chitobiose from chitin waste. Chitinase immobilization was feasible with an immobilization yield of 88.9 ± 1.6 % with 97.8 ± 1.0 % retention of activity and compared to free enzyme work, immobilization conferred better thermal and storage stability. As practical benefit the attachment to magnetic nanocarriers enabled easy enzyme recovery after repeated application runs and thus sustainable reuse. In fixed state chitinase retained a remarkable 39.7 ± 2.6 % of the starting activity after 16 reaction cycles. Furthermore, immobilized chitinase showed higher catalytic activity than free chitinase in converting shrimp shells and squid-pens chitins into di-N-acetyl chitobiose in a single-step reaction. The final yield of purified compound was 37.0 ± 1.2 % from shrimp shells and 61.1 ± 0.5 % from squid-pens chitin. In conclusion, an efficient MNP-based chitinase immobilization system with the potential for large-scale production was developed.
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  • 文章类型: Journal Article
    背景:低可发酵寡头饮食,di-,单糖和多元醇(LFD)可改善肠易激综合征(IBS)患者的症状。以前的研究集中在IBS和腹泻(IBS-D)患者上。目前尚不清楚LFD对便秘型IBS(IBS-C)或混合排便习惯型IBS(IBS-M)是否有效。这个开放标签,真实世界研究评估了IBS亚型之间LFD的相对有效性。
    方法:本研究分析了一项为IBS患者提供低FODMAP膳食服务的数据。参与者与注册营养师会面,并在进行2-4周的FODMAP限制之前和之后完成了IBS症状严重程度调查(IBS-SSS)。主要终点是三种IBS亚型之间IBS-SSS下降≥50点的参与者比例。
    结果:在FODMAP限制之后,90%的IBS-D参与者,75%与IBS-C,84%的IBS-M达到了主要终点(p=0.045)。下降了100点,也看到了类似的改善,但IBS亚型间差异不显著(p=0.46)。在FODMAP限制之后,所有组的总IBS-SSS以及个别症状类别均有统计学显著改善.除了腹胀严重程度(IBS-M改善最大)和排便满意度(IBS-C改善较少)的类别外,各组之间IBS-SSS亚类的改善相似。
    结论:尽管IBS-D的应答者比例最高,IBS-C的应答者比例最低,LFD导致所有IBS亚型的总体症状均有显著改善.关键的个体症状在所有IBS亚型中也显示出显著的改善。
    BACKGROUND: A diet low in fermentable oligo-, di-, monosaccharides and polyols (LFD) improves symptoms in patients with irritable bowel syndrome (IBS). Previous studies have focused on patients with IBS and diarrhea (IBS-D). It is unclear whether LFD is effective for IBS with constipation (IBS-C) or IBS with mixed bowel habits (IBS-M). This open-label, real-world study evaluates the relative effectiveness of the LFD among IBS subtypes.
    METHODS: This study analyzes data from a service that provides low-FODMAP meals to individuals with IBS. Participants met with a registered dietitian and completed the IBS symptom severity survey (IBS-SSS) before and after undergoing a 2-4-week period of FODMAP restriction. The primary endpoint was the proportion of participants with ≥50-point decrease in IBS-SSS between the three IBS subtypes.
    RESULTS: After FODMAP restriction, 90% of participants with IBS-D, 75% with IBS-C, and 84% with IBS-M met the primary endpoint (p = 0.045). Similar improvement was seen for a 100-point decrease, but the difference between IBS subtypes was not significant (p = 0.46). After FODMAP restriction, all groups had statistically significant improvement in total IBS-SSS as well as individual symptom categories. Improvement in IBS-SSS subcategories was similar among the groups except for the categories of bloating severity (IBS-M had greatest improvement) and bowel movement satisfaction (IBS-C had less improvement).
    CONCLUSIONS: Though the proportion of responders was highest for IBS-D and lowest for IBS-C, the LFD led to robust improvement in overall symptoms in all IBS subtypes. Key individual symptoms also showed significant improvements in all IBS subtypes.
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