Value of combining the serum D-lactate, diamine oxidase, and endotoxin levels to predict gut-derived infections in cancer patients

Objective:This is a retrospective observational cohort study.The objective of this retrospective observational cohort study was to evaluate the value of the combined serum D-lactic acid,diamine oxidase(DAO),and endotoxin levels to predict intestinal barrier impairment and gut-derived infection(GDI)in cancer patients.Methods:Cancer patients receiving chemotherapy or palliative care treatment at our hospital were enrolled in the study.The serum concentrations of DAO,D-lactic acid,and endotoxin were determined using the intestinal barrier function biochemical index analysis system.The patients'infection information came from the hospital's Medicom Prescription Automatic Screening System and themedical records.Three hundred fifty-three cancer patients were included in the study(53.8%female,73.7%cancer stage IV,27.8%had bowel obstruction).Results:The total incidence of GDI was 33.4%(118/353).The median length of hospital stay was 16 days for patients with GDI,compared with 7 days for patients without GDI(P<0.001).The media hospitalization costs were¥27,362.35 for patients with GDI compared with¥11,614.08 for patients without GDI(P<0.001).The serum concentrations of DAO,D-lactic acid,and endotoxin were significantly higher in patients with GDI.As malignant bowel obstruction(MBO)worsened,the concentrations of DAO,D-lactic acid,and endotoxin increased.Multivariate logistic regression models revealed that the DAO,endotoxin,IL-6,and C-reactive protein levels were significantly associated with an increased risk of GDI.In addition,we also found a fivefold increased risk of infection in patients withMBO compared with those without bowel obstruction(OR=6.210,P<0.001).All of the areas under the receiver operating characteristic curve(AUCs)for DAO,D-lactate,and endotoxin to predict GDI were<0.7(AUC=0.648,P<0.001;AUC=0.624,P<0.01;AUC=0.620,P<0.01,respectively).However,when the parameters were combined(DAO+D-lactate+endotoxin),the predictive power increased significantly(AUC=0.797,P<0.001).Moreover,combining these intestinal barrier indicators and the presence of MBO had better power to predict GDI than either alone(AUC=0.837,P<0.001).Conclusions:Combining the serum DAO,D-lactic acid,and endotoxin levels was a better predictor of GDI than any of the indicators alone,and combining these with the diagnosis of MBO could further improve the efficacy for predicting GDI.

Direct Electron Transfer Reactions of Glucose Oxidase and D-Amino Acid Oxidase at a Glassy Carbon Electrode in Organic Media

Cyclic voltammetry is employed to demonstrate feasibility of direct electron transfer of glucose oxidase and D amino acid oxidase at a glassy carbon electrode in organic media. The reversible slight conformational change of glucose oxidase is observed by changing 0.1 mol/L phosphate buffer to acetonitrile containing 10% v/v of water and 0.05 mol/L tetrabutyalammonium perchlorate, and vice versa.

Effect of TongFengNing Decoction on Uric Acid Levels and Xanthine Oxidase Activity in Hyperuricemia Rats

Objective To observe the effect of TongFengNing Decoction （TD） on uric acid levels, xanthine oxidase （XOD） activity, and XOD mRNA expression of hyperuricemia （HUA） model rats. Methods： 90 rats were randomly divided into 6 groups （n=15）, and the HUA model in all groups except the blank group was established by administering hypoxanthine （HX） by gavage and injecting potassium oxonate （OAPS） intraperitoneally. Rats in all TD groups and allopurinol group were administered multiple doses of TD and a single dose of allopurinol by gavage twice daily for 21 days, while the blank group and the model group were administered normal saline. On the 7th, 14th, and 21st days of drug intervention, serum uric acid （SUA）, urine uric acid （UUA）, intestinal uric acid （IUA）, as well as XOD activity and mRNA expression in the liver and small intestine were measured in randomly selected 5 rats of each group. Results： On the 14th and 21st days of intervention, all TD dose groups and the allopurinol group showed decreased SUA and IUA levels, increased UUA levels, as well as decreased XOD activity and mRNA expression in the liver and small intestine, compared with the model group （P 〈 0.05）. The low- and high-dose TD group and the allopurinol group showed increased SUA and IUA levels, as well as XOD activity and mRNA expression in the liver and small intestine, and decreased UUA levels, compared with the moderate-dose TD group （P〈0.05）. Upon extending the drug intervention time of each TD dose group, SUA and IUA levels, XOD activity, and XOD mRNA expression in the liver and small intestine decreased and UUA levels increased （P 〈 0.05）. Conclusion： TD reduces SUA levels in HUA model rats, which promotes uric acid excretion and inhibits XOD activity and XOD mRNA expression to reduce uric acid production. The reduction in uric acid level by the intermediate dose of TD was better than that by allopurinol and the low and high doses of TD.

高等植物赤霉素生物合成关键组分GA20-oxidase氧化酶基因的研究进展

GA-20氧化酶(GA-20 oxidase)是重要的GA生物合成和调控酶,直接催化生成有生物活性的GAs,是一种多功能酶,最显著的特点就是负反馈调节。GA20-氧化酶在植物发育和生理过程中起着重要的调控作用。综述了高等植物体内GA20氧化酶基因的克隆及表达调控研究及其对株高、纤维、开花、产量性状等影响,重点阐述了GA20氧化酶基因与激素、光周期、抗性等之间的相互作用,以便更好地揭示GA-20氧化酶信号网络系统及其作用机制。

赤霉素诱导甘蔗GA20-Oxidase基因实时荧光定量PCR分析

本研究以喷清水甘蔗幼茎作为对照(即未处理),经过赤霉素处理后6h、12h、24h和48h的甘蔗幼茎为处理,分别进行取样并提取RNA,反转录获得cDNA作模板,利用SYBR GreenⅠ成功构建了目的基因(GA20-oxidase)和内参基因(GAPDH)的标准品和标准曲线。结果表明:内参基因与目的基因的起始模板浓度与Ct之间呈良好线性关系,决定系数分别为r2=0.998、r2=0.995;溶解曲线均显单峰型,证明扩增的特异性比较好,可对基因表达进行相对定量。定量结果表明:目的基因未处理的表达量最大,赤霉素处理后表达量持续下降,在6h达到最低值,12h后逐渐上升,但到48h又明显下降,且所有处理的表达量均低于未处理,6h、12h、24h和48h比对照的表达量分别下降了24.75%、13.18%、10.23%和20.34%。本实验研究GA20-oxidase基因在赤霉素处理后的表达情况,为进一步克隆甘蔗GA20氧化酶基因全长序列、研究该基因在甘蔗节间伸长过程中的表达调控及甘蔗茎间伸长中的作用机理提供理论依据。

Inhibition of Xanthine Oxidase Activity by Gnaphalium Affine Extract

Objective To evaluate the inhibitory effect of Gnaphalium affine extracts on xanthine oxidase(XO) activity in vitro and to analyze the mechanism of this effect. Methods In this in vitro study, Kinetic measurements were performed in 4 different inhibitor concentrations and 5 different xanthine concentrations(60, 100, 200, 300, 400 μmol/L). Dixon and Lineweaver-Burk plot analysis were used to determine Ki values and the inhibition mode for the compounds isolated from Gnaphalium affine extract. Results Four potent xanthine oxidase inhibitors were found in 95% ethanolic(v/v) Gnaphalium affine extract. Among them, the f lavone Eupatilin exhibited the strongest inhibitory effect on XO with a inhibition constant(Ki) of 0.37 μmol/L, lower than the Ki of allopurinol(4.56 mol/L), a known synthetic XO inhibitor. Apigenin(Ki of 0.56 μmol/L, a proportion of 0.0053‰ in Gnaphalium affine), luteolin(Ki of 2.63 μmol/L, 0.0032‰ in Gnaphalium affine) and 5-hydroxy-6,7,3',4'-tetramethoxyflavone(Ki of 3.15 μmol/L, 0.0043‰ in Gnaphalium affine) also contributed to the inhibitory effect of Gnaphalium affine extract on XO activity. Conclusions These results suggest that the use of Gnaphalium affine in the treatment of gout could be attributed to its inhibitory effect on XO. This study provides a rational basis for the traditional use of Gnaphalium affine against gout.

Enhancement of α-ketoisovalerate production by relieving the product inhibition of L-amino acid deaminase from Proteus mirabilis

L-Amino acid deaminase(LAAD) is a key enzyme in the deamination of L-valine(L-val) to produce α-ketoisovalerate(KIV). However, the product inhibition of LAAD is a major hindrance to industrial KIV production.In the present study, a combination strategy of modification of flexible loop regions around the product binding site and the avoidance of dramatic change of main-chain dynamics was reported to reduce the product inhibition.The four mutant PM-LAAD^(M4)(PM-LAAD^(S98A/T105A/S106A/L341A)) achieved a 6.2-fold higher catalytic efficiency and an almost 6.7-fold reduction in product inhibition than the wild-type enzyme. Docking experiments suggested that weakened interactions between the product and enzyme, and the flexibility of the "lid" structure relieved LAAD product inhibition. Finally, the whole-cell biocatalyst PM-LAAD^(M4) has been applied to KIV production,the titer and conversion rate of KIV from L-val were 98.5 g·L^-1 and 99.2% at a 3-L scale, respectively. These results demonstrate that the newly engineered catalyst can significantly reduce the product inhibition, that making KIV a prospective product by bioconversion method, and also provide the understanding of the mechanism of the relieved product inhibition of PM-LAAD.

Study of Xanthine Oxidase Activity in Sera of Iraqi Children with Nephrotic Syndrome

Introduction: To investigate the relationship of xanthine oxidase activity with nephrotic syndrome disorder in children, and the optimization of the enzyme activity conditions in the disorder. Material and methods: Sera of children with nephrotic syndrome (NS) (60 samples) were obtained from Central Child Teaching Al Karama Hospital (CCTAH), from 2nd Mar. 2013 to 28th Feb. 2014. Sera of the patients were assayed for xanthine oxidase (XO) activity using colorimetric absorbance technique. The obtained results were compared with the enzyme activity of normal children (70 samples) as control. Results and conclusions: The results revealed a significant (P < 0.001) elevation in XO activity in serum of nephrotic syndrome (0.12 ± 0.06 IU/L) compared with that of normal subjects (0.05 ± 0.009 IU/L), showing an elevation of (70%) in XO activity (about 2/3) that of normal group. Factors influencing XO activities were also studied and showed that XO activity is a pH dependent. Significant elevation (P < 0.001) was found in uric acid level in sera of NS patients (497.52 ± 3.21 μmol/L) compared with that in normal group (298.12 ± 1.70 μmol/L). Elevation was found in urea level in sera of NS patient (10.69 ± 7.55 mmol/L) compared with that of normal group (4.57 ± 1.27 mmol/L). It was appeared, there is a role of XO activity in the pathogenesis of endothelial injury during glomerular lesion in NS and that was confirmed by comparing XO activity and other related conditions with the activity of normal volunteers.

Design, synthesis and in vitro evaluation of L-amino acid esters prodrugs of acyclic nucleoside phosphonates as anti-HBV agent

A series of novel L-amino acid esters prodrugs of acyclic nucleoside phosphonates was synthesized and their anti-HBV activity was evaluated in HepG2 2.2.15 cells. Compound 1d exhibited more potent anti-HBV activity and lower cytotoxicity than those of adefovir dipivoxil with EC50 and CC50 values of 0.207 μmol/L and 2530 μmol/L, respectively.

Transgenic Arabidopsis thaliana expressing a wheat oxalate oxidase exhibits hydrogen peroxide related defense response

Oxalic acid（OA） is considered as an important pathogenetic factor of some destructive diseases caused by some fungal pathogens such as Sclerotinia sclerotiorum. Oxalate degradation is important for plant health, and plants that contain oxalate oxidase（OXO） enzymes could breakdown oxalate into CO_2 and H_2O_2, which subsequently evokes defense responses. However, some species, such as Arabidopsis thaliana, have no oxalate oxidase activity identified to date. The present study aims to develop transgenic Arabidopsis expressing a wheat oxalate oxidase, to test for the response to OA exposure and fungal infection by S. sclerotiorum. The results showed that the transgenic Arabidopsis lines that expressed the wheat OXO exhibited enhanced resistance to OA exposure and S. sclerotiorum infection in the tolerance assays. In the same manner, it could convert OA to CO_2 and H_2O_2 to a higher extent than the wild-type. Intensive osmotic adjustments were also detected in the transgenic Arabidopsis lines. The higher level of produced H_2O_2 subsequently induced an elevated activity of antioxidant enzymes including superoxide dismutase（SOD） and peroxidase（POD） in the transgenic Arabidopsis plants. The present study indicated that the expression of a gene encoding wheat OXO could induce intensive osmotic adjustments and hydrogen peroxide related defense response, and subsequently increased tolerance to S. sclerotiorum in transgenic A. thaliana.

Aromatic L-amino acid decarboxylase cells in the spinal cord:a potential origin of monoamines

Monoamine neurotransmitters include catecholamines and indoleamines. The most common catecholamines are do- pamine （DA）, noradrenaline （NA） and adrenaline, which are produced from phenylalanine and tyrosine; whereas the most common indoleamine is serotonin （5-hydroxytrypta mine, 5-HT）, which is produced from 5-hydroxytryptophan （5-HTP）.

High-starchy carbohydrate diet aggravates NAFLD by increasing fatty acids influx mediated by NOX2

Nonalcoholic fatty liver disease(NAFLD)is a high-incidence lipid disorder that affects more than a quarter of the population worldwide,and dietary intervention is the recognized treatment.Starch is the main component of staple foods that are consumed daily,and the effects,metabolic pathway,and molecular mechanism of starch in the context of NAFLD remain unclear.Our study showed that a high-starch carbohydrate diet(HCD)led to the occurrence and exacerbation of NAFLD in mice.Transcriptomics and metabonomic analyses showed that the increased fatty acid influx mediated by NADPH oxidase 2(NOX2)exacerbated NAFLD.Knocking down NOX2 specifically alleviated HCD-induced NAFLD in vivo and in vitro.Moreover,the large amounts of ROS produced by NOX2 further exacerbated insulin resistance and increased lipolysis in perirenal white adipose tissue(periWAT),thereby providing fatty acids for hepatic lipid synthesis.In addition,the interaction between AMPKα1 and p47phox was the pathway that mediated the high expression of NOX2 induced by a HCD.Our study systematically demonstrated the effect of a HCD on NAFLD.Elevated fatty acid influx is a unique molecular regulatory pathway that mediates HCD-induced NAFLD exacerbation,which is different from the effect of simple sugars.Additionally,NOX2 was suggested to be a specific and effective drug target for NAFLD.

Biosynthesis of 4-hydroxyphenylpyruvic acid from L-tyrosine using recombinant Escherichia coli cells expressing membrane bound L-amino acid deaminase

4-Hydroxyphenylpyruvic acid （4-HPPA）, a kind of α-keto acid, is an intermediate in the metabolism of tyrosine and has a wide range of application in food, pharmaceutical and chemical industry. Using amino acids as raw material to prod uce the corresponding α-keto acid is thought to be both economic and efficient. Among the enzymes that convert amino acid to α-keto acid, membrane bound L-amino acid deaminase （mL-AAD）, which is anchored to the outer side of the cytomembrane, becomes an ideal enzyme to prepare α-keto acid since there is no cofactors needed and H2O2 production during the reaction. In this study, the mL-AAD from Proteus vulgaris was used to prepare whole-cell catalysts to produce 4-HPPA from L-tyrosine. The secretory efficiency of mL-AAD conducted by its own twin-arginine signal peptide （twin-arginine translocation pathway, Tat） and integrated pelB （the general secretory pathway, Sec）-Tat signal peptide was determined and compared firstly, using two pET systems （pET28a and pET20b）. It was found that the Tat pathway （pET28a-mlaad） resulted in higher cell-associated mL-AAD activity and cell biomass, and was more beneficial to prepare biocatalyst. In addition, expression hosts BI21 （DE3） and 0.05 mmol. L- 1 IPTG were found to be suitable for mL-AAD expression. The reaction conditions for mL-AAD were optimized and 72.72 mmol,L 1 4-HPPA was obtained from 100 mmol.L 1 tyrosine in 10 h under the optimized conditions. This bioprocess, which is more eco-friendly and economical than the traditional chemical synthesis ways, has great potential for industrial application.

饲粮中复合添加马齿苋、柠檬酸和葡萄糖氧化酶对肉兔生长性能、屠宰性能以及免疫和抗氧化功能的影响

本试验旨在研究饲粮中复合添加马齿苋、柠檬酸和葡萄糖氧化酶对肉兔生长性能、屠宰性能以及免疫和抗氧化功能的影响。试验选取200只健康的35日龄断奶伊拉商品肉兔(公母各占1/2),按照体重和性别随机分为4组,每组50个重复,每个重复1只兔。对照组饲喂基础饲粮,试验1组饲喂在基础饲粮中添加3%马齿苋替换等量麸皮的饲粮,试验2组和试验3组分别饲喂在试验1组饲粮基础上添加1%柠檬酸和1%柠檬酸+200 mg/kg葡萄糖氧化酶的饲粮。预试期7 d,正试期35 d。结果表明:1)与对照组相比,试验2组和试验3组肉兔终末体重显著提高(P<0.05),死亡率显著降低(P<0.05),腹泻频率有降低趋势(0.05<P<0.10);试验2组肉兔平均日增重和平均日采食量显著提高(P<0.05);试验3组肉兔料重比和平均日采食量显著低于试验1组和试验2组(P<0.05)。2)与对照组相比,3个试验组肉兔半净膛屠宰率显著提高(P<0.05),试验1组和试验2组肉兔全净膛屠宰率显著提高(P<0.05)。3)与对照组相比,3个试验组肉兔血清免疫球蛋白G含量显著提高(P<0.05),试验1组和试验2组肉兔血清白细胞介素-1β含量显著降低(P<0.05),试验2组和试验3组肉兔血清白细胞介素-6(IL⁃6)含量显著降低(P<0.05);试验3组肉兔胸腺指数显著高于试验1组(P<0.05),血清IL⁃6含量显著低于试验1组(P<0.05)。4)各组间肉兔肝脏抗氧化指标均无显著差异(P>0.05)。综上所述,饲粮中复合添加马齿苋、柠檬酸和葡萄糖氧化酶能够提高肉兔生长性能和屠宰性能,提高机体免疫力,降低死亡率和腹泻频率。

龙胆苦苷对果糖诱导小鼠高尿酸血症的作用

目的:研究龙胆苦苷对果糖诱导小鼠高尿酸血症的治疗作用。方法:昆明种小鼠连续饮用10%果糖溶液12周以制备高尿酸症小鼠模型,从第9周开始,别嘌呤醇组,龙胆苦苷高、中、低剂量组(80 mg/kg、40 mg/kg、20 mg/kg-)每天灌胃给药1次,共给药4周。末次给药后取血,检测血清谷丙转氨酶(GPT)、谷草转氨酶(GOT)、尿酸(UA)、肌酐(Cr)和血尿素氮(BUN)水平,苏木精-伊红(HE)染色观察肝、肾组织的变化;酶联免疫吸附试验法检测肾组织中超氧化物歧化酶(SOD),丙二醛(MDA),肿瘤坏死因子α(TNF-α)和白细胞介素-6(IL-6)水平,比色法和蛋白质免疫印迹法检测肝组织中黄嘌呤氧化酶(XOD)活性及蛋白表达水平。结果:与模型组比较,龙胆苦苷各给药组小鼠血清GPT、GOT、UA、Cra和BUN水平显著降低(P<0.01),肝、肾病理学变化有所改善;肾脏SOD水平显著升高(P<0.01),MDA、TNF-α和IL-6水平显著降低(P<0.01);同时肝脏XOD的活性及蛋白表达水平显著下调(P<0.01或P<0.05)。结论:龙胆苦苷通过降低XOD活性和表达,降低尿酸水平,进而减轻肾脏氧化应激和炎症水平,达到肾脏保护作用。

灵芝水提物对高尿酸血症大鼠尿酸含量和肾功能的影响

测定灵芝(Ganodermalucidum)水提物总糖、还原糖、多糖、蛋白质和核苷类物质含量及其对DPPH和ABTS自由基清除能力;采用腺苷诱导肝细胞L-O2建立体外高尿酸细胞模型,研究灵芝水提物(低、中、高剂量分别为0.25、0.50、1.00 mg·mL^(-1))对肝细胞L-O2培养液中尿酸含量的影响;基于氧嗪酸钾联合酵母膏喂养建立高尿酸大鼠模型,采用灵芝水提物(低、中、高剂量分别为0.5、1.0和2.0 g·kg^(-1))灌胃大鼠,测定大鼠血清和肝脏组织黄嘌呤氧化酶活性,血清和肾脏组织尿酸、血清肌酐和尿素氮含量;采用苏木精-伊红染色肝脏、肾脏组织,观察并测定细胞核质比。结果表明:0.25、0.50和1.00 mg·mL^(-1)灵芝水提物对DPPH的清除率显著高于其对ABTS的清除率。与模型组比较,灵芝水提物低、中、高剂量组肝细胞L-O2培养液中尿酸含量显著降低;中、高剂量组血清中的尿酸含量显著降低;低、中、高剂量组肾脏中的尿酸含量显著增加;中、高剂量组肾脏组织细胞的核质比、血清尿素氮含量显著降低;低、中、高剂量组血清肌酐含量极显著降低;低、中、高剂量组肝脏细胞的核质比显著降低;中、高剂量组血清、肝脏组织黄嘌呤氧化酶活性显著降低。研究结果可为灵芝相关功能产品的开发提供参考。

桑黄游离酚提取物体外降尿酸活性研究

为研究桑黄游离酚提取物体外降尿酸活性,以野生瓦宁木层孔菌、栽培粗毛纤孔菌、栽培瓦宁木层孔菌和野生粗毛纤孔菌4个不同来源的桑黄为研究对象,分析不同来源桑黄游离酚提取物对黄嘌呤氧化酶的抑制活性,及其在高尿酸细胞模型中的降尿酸作用。筛选出降尿酸活性强的桑黄游离酚提取物,并通过超高效液相色谱-串联质谱(ultra performance liquid chromatography/tandem mass spectrometry,UPLC-MS/MS)对其降尿酸活性物质进行分析。研究结果表明,栽培粗毛纤孔菌、栽培瓦宁木层孔菌和野生粗毛纤孔菌的游离酚提取物对黄嘌呤氧化酶具有显著的抑制作用(P<0.05),IC_(50)值分别为(94.63±2.73)μg/mL、(99.69±2.50)μg/mL和(106.32±5.06)μg/mL;栽培粗毛纤孔菌和野生瓦宁木层孔菌的游离酚提取物可显著抑制高尿酸细胞模型中尿酸生成(P<0.05)。进一步通过UPLC-MS/MS分析活性较强的栽培粗毛纤孔菌游离酚中主要成分发现,其黄酮类物质中金丝桃苷、表儿茶素、茶黄素、地奥司明及木犀草苷等,可能是其降尿酸的主要活性物质。该研究可为桑黄降尿酸产品的研究与开发提供部分理论参考。

菌株X3-2B和37X-3体外抑制黄嘌呤氧化酶能力及其对小鼠高尿酸血症缓解作用的研究

为探究菌株X3-2B和37X-3对黄嘌呤氧化酶(xanthine oxidase, XOD)的抑制能力和对小鼠高尿酸血症(hyperuricemia, HUA)的缓解作用,利用HPLC测定菌株X3-2B和37X-3在含有黄嘌呤和XOD的培养环境中培养20、40、60、80、100 min时,培养基中黄嘌呤和尿酸(uric acid, UA)的含量;调节培养基pH和胆盐浓度,检测不同pH和胆盐浓度下的活菌数,研究菌株X3-2B和37X-3在体外对XOD的抑制能力和耐酸耐碱特性。将60只KM小鼠随机分为5组:对照组(C组)、模型组(M组)、X3-2B组(X组)、37X-3组(L组)和别嘌呤醇组(P组),除C组饲喂对照饲料外,其他各组均饲喂高嘌呤饲料。小鼠共喂养4周,每日给X组、L组和P组小鼠分别灌胃相应剂量的菌株X3-2B、37X-3和别嘌呤醇,通过对小鼠生理生化指标、肾脏病理学切片和肠道组织XOD活性分析,研究菌株X3-2B、37X-3对小鼠HUA的缓解作用。研究指出菌株X3-2B和37X-3可以有效抑制XOD催化黄嘌呤生成UA;在pH 2和胆盐添加量3 g/L时,X3-2B和37X-3的活菌数分别为6.4×10^(7) CFU/g(X3-2B)、9.3×10^(7) CFU/g(37X-3)和2.1×10^(6) CFU/g(X3-2B)、2.8×10^(6) CFU/g(37X-3);小鼠喂养4周后,X组和L组小鼠血清中UA、血尿素氮(blood urea nitrogen, BUN)和肌酐(creatinine, Cr)含量显著下降(P<0.05),肾单位结构完整,肠道组织中XOD活性被抑制(P<0.05)。得出菌株X3-2B和37X-3可以有效抑制XOD活性,减少UA生成;并且可以在HUA小鼠肠道中发挥XOD抑制功能,缓解小鼠HUA。

黑莓1-氨基环丙烷-1-羧酸氧化酶基因RuACO 1a和RuACO 1b的克隆及功能鉴定

基于前期黑莓(Rubus spp.)品种‘Navaho’果实转录组测序结果,通过反转录PCR克隆获得2个1-氨基环丙烷-1-羧酸氧化酶(ACO)基因,命名为RuACO 1a和RuACO 1b。结果表明:RuACO 1a和RuACO 1b的开放阅读框(ORF)长度分别为939和918 bp,分别含有4和3个外显子。系统进化分析结果显示RuACO1a和RuACO1b与月季(Rosa chinensis Jacq.)、蕨麻〔Argentina anserina(Linn.)Rydb.〕和野草莓(Fragaria vesca Linn.)ACO1蛋白的亲缘关系均较近,且分别属于蔷薇科(Rosaceae)植物中2类ACO1蛋白。RuACO 1a在果实着色后28 d响应乙烯利诱导,其相对表达量急剧升高,而RuACO 1b在果实着色后21 d响应乙烯利诱导,早于RuACO 1a。脱落酸处理后,RuACO 1a和RuACO 1b的相对表达量在果实着色后14和28 d较高。RuACO 1a和RuACO 1b具有组织表达特异性,RuACO 1a在幼果、花蕾和花中的相对表达量较高,RuACO 1b在幼果和幼根中的相对表达量较高。与野生型相比,RuACO 1a和RuACO 1b过量表达转基因拟南芥〔Arabidopsis thaliana(Linn.)Heynh.〕植株均表现为叶片中叶绿素相对含量和氮含量升高、开花和角果成熟提前、ACO含量升高。综上所述,黑莓RuACO 1a和RuACO 1b基因均促进拟南芥角果提前成熟。

平卧菊三七提取物降尿酸活性的物质基础分析

为探究平卧菊三七降尿酸活性物质基础,评价不同乙醇体积分数(0%、30%、70%)回流提取对平卧菊三七提取物有效成分含量、黄嘌呤氧化酶(xanthine oxidase,XOD)抑制能力及抗氧化活性的影响,利用非靶向代谢组学技术对提取物进行物质鉴定分析,同时,建立次黄嘌呤和氧嗪酸钾造模的高尿酸血症小鼠模型,以XOD抑制活性较高的30%醇提物和70%醇提物进行体内降尿酸效果评价。结果表明,提取物的XOD抑制活性和总黄酮、总有机酸含量呈显著正相关(P<0.05、P<0.01),超氧阴离子自由基清除能力与总酚含量呈显著正相关(P<0.01)。非靶向代谢组学共检测出705种差异代谢物,结合体外实验结果,推测柚皮素、1,5-二咖啡酰奎宁酸、α-亚麻酸、阿魏酸、香叶木素等物质为平卧菊三七降尿酸关键物质。30%和70%醇提物均可通过降低血清尿酸和抑制XOD缓解高尿酸血症(P<0.01),且一定程度上缓解高尿酸血症带来的肝脏氧化损伤。本研究通过体内和体外实验验证平卧菊三七具备降尿酸活性,对平卧菊三七降尿酸物质基础进行探讨,为平卧菊三七降尿酸活性物质的制备和功能食品开发提供理论依据。