Fast determination of Sudan dyes in chilli tomato sauces using partial filling micellar electrokinetic chromatography

A new method based on partial filling micellar electrokinetic chromatography (MEKC) for the quantitative determination of Sudan dyes (I, II, III, and IV) in chilli sauces is presented. The separation is achieved filling 25% of the capillary with a MEKC buffer composed of 40 mM NH(4)HCO(3), 25 mM sodium dodecyl sulfate, and 32.5% (v/v) acetonitrile (ACN). The rest of the capillary is filled using a capillary zone electrophoresis (CZE) buffer composed of 40 mM NH(4)HCO(3) and 32.5% (v/v) ACN. Under optimized conditions, the azo dyes are baseline separated in less than 8 min with limits of detection ranging from 0.57 to 0.71 μg mL(-1) (S/N > 3). Using an internal standard, the repeatability of the quantitative determination is improved almost four times. The applicability of the method for rapid screening and determination of Sudan dyes is corroborated by analyzing spiked chilli sauce samples with recoveries from 85 to 99%. The reported conditions are demonstrated to be compatible with mass spectrometry detection.     

Determination of 4(5)-methylimidazole in soy sauce and other foods by LC-MS/MS after solid-phase extraction

A method for the determination of 4(5)-methylimidazole (4MeI) in naturally brewed soy sauce was developed for the first time using solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). SPE on silica-based reversed-phase cartridges with heptafluorobutyric acid as an ion-pairing reagent was used for the efficient cleanup of 4MeI. A multimode ODS column was employed for the chromatographic separation. To subtract the matrix effect during LC-MS/MS analysis, a standard addition method was used. The levels of 4MeI found in naturally brewed soy sauce were extremely low (ranging from <0.002 to 0.023 μg/g), whereas those in soy sauces containing caramel color were generally high (ranging from 0.43 to 4.8 μg/g). The method proved to be useful for the analysis of 4MeI in other foods such as caramel colors, drinks, and Worcestershire sauce.     

不同施肥对双季稻田径流氮磷流失特征的影响

通过定位试验,研究了不施氮肥(WN)、单施化肥(HF)、猪粪替代20%氮肥(ZF)、沼渣沼液替代20%氮肥(ZYF)、堆肥替代20%氮肥(DF)、早稻绿肥、晚稻稻草代替20%氮肥(LDF)6种不同施肥处理下双季稻径流氮磷含量和累积流失负荷的影响。结果表明,水稻基肥和追肥后,径流水中全氮、硝态氮、铵态氮、全磷和水溶性磷含量逐渐下降。HF处理双季稻季径流水中全氮、铵态氮、硝态氮平均含量最高,分别为5.91,3.65,0.82mg/L。相比HF处理,有机物料替代20%氮肥处理能够降低径流水中全氮、铵态氮、硝态氮的平均含量,其中以DF处理下降幅度最大,分别下降1.18,0.71,0.14mg/L;除DF处理外,有机物料替代20%氮肥能够增加径流水中全磷和水溶性磷的平均含量。相比HF处理,有机物料替代20%氮肥能够减少氮素径流流失负荷,以DF处理总氮、铵态氮和硝态氮累积流失负荷最小,分别为10.25,6.17,1.71kg/hm2;DF处理磷素流失负荷与单施化肥处理持平。综上,DF处理能够降低径流水中氮磷流失负荷,对于保护环境和控制面源污染具有重要意义。     

三种氮肥对红壤硝化作用及酸化过程影响的研究

以安徽郎溪耕地红壤耕层土壤为对象,采用室内恒温培养方法,研究了CO(NH2)2、(NH4)2SO4及NH4HCO3 3种氮肥在不同施用量条件下对土壤硝化作用及酸化过程的影响。结果表明:对照处理土壤的净硝化速率为(NO2-+NO3-)-N 25.7 mol /(kg?d);3种化学氮肥添加到土壤后均显著促进了土壤的硝化作用,CO(NH2)2、NH4HCO3处理土壤的净硝化速率分别为(NO2-+NO3-)-N 51.3～189.6、50.7～149.9 mol /(kg?d),且净硝化速率随氮肥用量增加而增加;(NH4)2SO4处理土壤的净硝化速率为(NO2-+NO3-)-N 60.5～107.9 mol /(kg?d),以施用量N 150 mg /kg时最大。研究同时发现, 3种化学氮肥均导致土壤pH下降,CO(NH2)2、 NH4HCO3处理土壤pH较对照处理分别下降0.11～0.43、0.02～0.36 pH单位,氮肥施用越多,pH下降越大;(NH4)2SO4处理土壤pH较对照处理下降0.08～0.26 pH单位,以施用量N 150 mg /kg时下降最大, N 300 mg /kg时下降最小。统计分析表明,土壤pH与土壤中(NO2-+NO3-)-N含量呈极显著负相关,土壤酸化速率与净硝化速率有显著的线性相关关系,说明氮肥通过硝化作用影响土壤酸度。     

结合条件对羊抗兔抗体连接到细菌磁小体的影响

用羊抗兔抗体进行抗体连接到细菌磁小体(BMPs)实验，以探讨结合条件对抗体连接效率(以每毫克BMPs上连接抗体的微克数表示，单位为μg/mg)的影响。实验表明，冷冻干燥后的BMPs的抗体连接效率降低36%~55%；在液氮中(-196 ℃)预处理的抗体连接效率显著高于在-70 ℃和-20 ℃预处理的。室温(15 ℃)下反应18 h的抗体连接效率最高，为64.06 μg/mg，明显高于其它温度和连接时间的。反应体系中，BMPs用量由5 mg降到0.1 mg，抗体用量由10 μg增加到300 μg时，抗体连接效率逐渐上升，当BMPs用量为0.1 mg，抗体用量为300 μg时，抗体连接效率达762.37 μg/mg。PBS、HEPES、Tris-HCl、MOPS、VBS以及磷酸盐等溶液可用于抗体连接到BMPs体系中，在通常使用的缓冲液pH和浓度下，几种溶液的抗体连接效率变化范围为46.28±0.58 ~ 90.83±1.64 μg/mg；并且不同的溶液有相应的使抗体连接效率达到最高时的pH和溶液浓度，当HEPES的pH为3.5，浓度为20 mmol / L；Na3PO4的pH为5.6，浓度为5 mmol / L时，抗体连接效率分别为108.01和76.78 μg/mg。对连接到BMPs上的抗体进行SDS-PAGE定性检测结果表明，抗体连接到了BMPs的膜上。     

1,2-dicarbonyl compounds in commonly consumed foods

1,2-Dicarbonyl compounds, formed from carbohydrates during thermal processing in the course of caramelization and Maillard reactions, are intensively discussed as precursors for advanced glycation endproducts in foods and in vivo. To obtain information about the uptake of individual compounds with commonly consumed foods, a comprehensive analysis of the content of 3-deoxyglucosone (3-DG), 3-deoxygalactosone (3-DGal), and methylglyoxal (MGO) together with 5-hydroxymethylfurfural (HMF) in 173 food items like bakery products, pasta, nonalcoholic and alcoholic beverages, sweet spreads, and condiments was performed. Following suitable cleanup procedures, 1,2-dicarbonyl compounds were quantitated after derivatization with o-phenylenediamine via RP-HPLC with UV detection. 3-DG proved to be the predominant 1,2-dicarbonyl compound with concentrations up to 410 mg/L in fruit juices, 2622 mg/L in balsamic vinegars, and 385 mg/kg in cookies, thus exceeding the corresponding concentrations of HMF. 3-DGal was found to be of relevance in many foods even in the absence of galactose. MGO was only of minor quantitative importance in all foods studied, except for manuka honey. Dietary intake was estimated to range between 20 and 160 mg/day for 3-DG and 5 and 20 mg/day for MGO, respectively.     

Anti-stress effects of Glycine tomentella Hayata in tilapia: inhibiting COX-2 expression and enhancing EPA synthesis in erythrocyte membrane and fish growth

The objective of this study was to elucidate the in vivo effects of the ethanol extract of wooly Glycine tomentella Hayata (GTE) root on tilapia to elucidate whether GTE has antistress activity. Tilapia as an animal model were fed with or without GTE, then injected with lipopolysaccharide (LPS) or ammonium chloride (NH(4)Cl). The tilapia were exposed to 100 mg/L of aqueous NH(4)Cl, and/or acute cold stress. Growth parameters of the tilapia were measured during the feeding trials. Tilapia injected with GTE (20 μg/g of fish), NH(4)Cl (100 μg/g of fish) and/or LPS (1 μg/g of fish) were then sampled 2 h poststimulation. GTE significantly inhibited cyclooxygenase-2 expression and hemoglobin (Hb) dimer formation (36 kDa). GTE also improved growth and blood viscosity and upregulated eicosapentaenoic acid content of erythrocytes. The in vivo results indicated that GTE (20 μg/g of fish) can be applied as a stress-tolerance enhancing agent for the aquaculture industry.     

Formation of arginine modifications in a model system of Nα-tert-butoxycarbonyl (Boc)-arginine with methylglyoxal

The present study deals with the mechanistic reaction pathway of the α-dicarbonyl compound methylglyoxal with the guanidino group of arginine. Eight products were formed from the reaction of methylglyoxal with N(α)-tert-butoxycarbonyl (Boc)-arginine under physiological conditions (pH 7.4 and 37 °C). Isolation and purification of substances were achieved using cation-exchange chromatography and preparative high-performance liquid chromatography (HPLC). Structures were verified by nuclear magnetic resonance (NMR) and high-resolution mass spectrometry. 2-Amino-5-(2-amino-4-hydro-4-methyl-5-imidazolinone-1-yl)pentanoic acid (3) was determined as the key intermediate precursor within the total reaction scheme. Kinetic studies identified N(δ)-(5-methyl-4-oxo-5-hydroimidazolinone-2-yl)-L-ornithine and N(7)-carboxyethylarginine as thermodynamically more stable products from compound 3. Further mechanistic investigations revealed an acidic hydrogen at C-8 of compound 3 to trigger aldol condensations. This reactivity of compound 3 allowed for the addition of another molecule of methylglyoxal to form products, such as N(δ)-(4-carboxy-4,6-dimethyl-5,6-dihydroxy-1,4,5,6-tetrahydropyrimidine-2-yl)-l-ornithine and argpyrimidine.     

剩余污泥厌氧发酵混合物提高低C/N污水处理效果

为了避免剩余污泥厌氧发酵液利用时泥液难分离的问题,探讨了直接将发酵混合物用作外加碳源处理低碳氮比(C/N)污水的可行性。为此,首先对比了酸性(pH值=4.0±0.2)、中性(不控pH值)、碱性(pH值=10.0±0.2)条件下长期运行的剩余污泥厌氧发酵混合物的特性;其次,分别考察了碱性厌氧发酵混合物的不同投加量(0、10、20、30、50、100、200 mL),在反硝化及释磷过程中的利用。结果表明:碱性条件下溶解性化学需氧量(soluble chemical oxygen demand,SCOD)和短链脂肪酸(short-chain fatty acids,SCFAs)产量要远高于酸性和中性条件的,其中C/N比和C/P比分别高达18.9和57.0,更适合作为外加碳源利用。反硝化过程中,当初始NO_3~--N=(15.0±0.5)mg/L时,最佳投加量为30 mL,此时NO_3~--N去除率为100%;释磷过程中,最佳投加量为20 mL,此时最大净释磷量为22.8 mg/L。剩余污泥碱性厌氧发酵混合物用作外加碳源是可行的,既解决了碳源不足及剩余污泥处理的双重问题,又简化了传统发酵液利用时泥液分离的操作步骤,适用于处理低C/N比乡镇生活污水。     

氮素形态和光照强度对水稻表土及根际 N2O 排放的影响

【目的】 稻田生态系统是 N₂O 的重要排放源,本研究旨在探讨氮素形态和光照对水稻根际、叶际 N₂O 排放作用及其机制。 【方法】 试验采用水培方法,在小型光控培养箱内进行,供试作物为水稻。将水稻地上部和地下部严格分隔在试验装置内室和外室,用气相色谱法测定水稻根、叶界面排放的 N₂O 量。首先进行了弱光 (8:00～18:00, 4000 Lux;18:00～22:00, 0 Lux) 和供氮量一致条件下 (N 90 mg/L),NO₃–-N、NH₄NO₃ 和 NH₄+-N 3 种氮素形态对水稻根、叶界面 N₂O 排放的影响的试验。在此基础上,进行了不同光照条件下 [弱光 (8:00～18:00, 4000 Lux; 18:00～22:00, 0 Lux)、强光 (8:00～18:00, 8000 Lux; 18:00～22:00, 0 Lux) 和自然光]不同氮素形态对水稻根、叶界面 N₂O 排放的影响的试验。 【结果】 1) 相同供氮水平、弱光条件下,NO₃–-N、NH₄NO₃、NH₄+-N 处理的水稻分蘖期叶际及根际 N₂O 排放速率分别为 6.37、5.03、0.46 μg/(pot·h) 和 16.30、15.71、1.31 μg/(pot·h),开花结实期及成熟衰老期亦获得相似的结果。NO₃–-N、NH₄NO₃ 处理水稻根际、叶际 N₂O 排放量显著高于 NH₄+-N ( P < 0.05)。 2) 弱光照条件下,NO₃–-N、NH₄NO₃ 和 NH₄+-N 处理的水稻开花结实期叶际 N₂O 平均排放速率分别为 10.47、3.70、0.26 μg/(pot·h),强光照条件下分别为 20.83、10.82、2.08 μg/(pot·h),两种光照条件下 3 种氮源处理之间 N₂O 平均排放速率差异显著,自然光照条件下 NO₃–-N 与 NH₄NO₃ 处理间水稻叶际 N₂O 排放差异不显著。 3) 在弱光条件下,NO₃–-N、NH₄NO₃ 和 NH₄+-N 处理的水稻根际 N₂O 排放速率分别为 27.76、5.19、0.30 μg/(pot·h),强光条件下分别为 32.83、16.41、1.27 μg/(pot·h),自然光条件下分别为 16.49、20.21、1.74 μg/(pot·h)。NH₄NO₃ 处理水稻根际 N₂O 排放随光照增强而增加,自然光条件下 NO₃–-N 与 NH₄NO₃ 处理间水稻根际 N₂O 排放差异不显著,但弱光条件下差异显著; 4) 叶际 N₂O 排放速率 ( Y) 与根际 N₂O 排放速率 ( X) 间呈极显著正相关, Y = 1.963 + 0.444 X ( R2 = 0.661, P < 0.01)。 【结论】 不论光照条件强弱,供应 NO₃–-N 均显著提高水稻根、叶界面的 N₂O-N 排放,NH₄NO₃ 次之。光照越强,排放就越明显。叶际 N₂O 排放可以反映出根际的排放,因此,水稻施肥应尽量选用铵态氮肥,避免使用硝态氮以及含有硝态氮的肥料。      

鸡胚原始生殖细胞的分离、培养及鉴定

采用Ficoll密度梯度离心法分离第19期(孵化68～72 h)艾维茵鸡(Gallus domesticus)生殖嵴原始生殖细胞(PGC)，通过体细胞-PGC共培养进行了原代和传代培养，对PGC进行了碱性磷酸酶(AKP)和过碘酸雪夫氏反应(PAS)鉴定，并用细胞增殖核抗原(PCNA)免疫细胞化学检测了传代于鸡胚饲养层上PGC的增殖活性。培养的PGC经AKP和PAS鉴定均为阳性，AKP阳性为红棕色，PAS阳性为深红色，PCNA染色显示PGC集落为红棕色，表明PGC处于增殖状态。同时比较了不同体外培养条件(5%~20%胎牛血清(FCS), ITS培养液(M199+ 10 μg/mL 胰岛素+5 μg/mL转铁蛋白+3×10-8 mol/L亚硒酸钠), 条件培养液, 15%FCS+ITS, 15%FCS+40% 条件培养液)下PGC增殖情况。发现未经密度梯度离心的PGC生长较离心的PGC好，且5%FCS在原代培养中起较好的促增殖作用；而传代培养时在不同培养条件下，5%FCS组或ITS组形成的PGC集落的直径较大，而仅用单纯的条件培养液效果并不明显。结果表明除鸡胚饲养层可作为PGC增殖的支持体系外，在体细胞-PGC共培养方式下5%FCS或单独的ITS也可作为PGC体外增殖的一种培养体系。     

固液气分流式瘤胃模拟系统的设计与测试

针对现有批次培养和连续培养瘤胃模拟装置存在的不足,设计了一种在不影响系统气密性的情况下,由计算机自动控制的固液气分流式连续培养瘤胃模拟系统。并进行了为期10d的培养试验。试验表明:本系统的各发酵参数平行性好,4个发酵罐PH值从第5天开始稳定,变化趋势与牛瘤胃内pH值变化一致;各发酵单元从第3天开始,原虫数量稳定在(0.99±0.32)×104个/mL(p=0.6877),溢流液中氨态氮的浓度维持在(3.91±1.10)mg/100mL;试验全期干物质消失率为62%±2%,总排气次数为(2370±33)次,总挥发性脂肪酸为(41.77±3.78)mmol/L(p=0.488)。因此该固液气分流式连续培养瘤胃模拟系统综合了批次培养和连续培养瘤胃模拟装置的特点,并能有效的模拟瘤胃发酵状况。     

Maillard reaction of D-glucose: identification of a colored product with hydroxypyrrole and hydroxypyrrolinone rings connected by a methine group

Investigation of the colored products formed by the reaction of d-glucose with butylammonium acetate has been extended. The previously unknown 1-N-butyl-4-hydroxy-5-methyl-2-(N-butyl-3-hydroxy-5-(2-hydroxyethyl)pyrrolyl-2-methylidene)-2H-pyrrolin-3-one (2a) was isolated from the reaction mixture and identified after acylation by spectroscopic data. Butylaminammonium acetate was used as a model compound representing the lysine side chains of proteins.     

戴云山自然保护区森林土壤氮转化特点研究

利用~(15)N稳定同位素成对标记法并结合MCMC数值模型,研究了戴云山国家级自然保护区天然毛竹林(BF)及其邻近黄山松–杉木林(NF)土壤氮素初级转化速率,以评估该地区森林生态系统土壤氮状态,并分析其保氮机制。结果表明:BF土壤NH_4~+-N的总产生速率(以N量计,13.16μg/(g×d))是NF土壤的2倍(6.25μg/(g×d)),其中黏土矿物对NH_4~+-N的解吸作用是BF产生NH_4~+-N的主要过程(55%),而NF主要以有机氮的矿化作用为主(56%)。BF土壤氮素初级矿化速率为5.56μg/(g×d),显著高于NF的3.40μg/(g×d)。土壤氮素初级矿化速率与土壤全氮含量显著正相关(P0.05),而与C/N比表现显著负相关(P0.05)。BF与NF土壤NH_4~+-N总产生量的90%均被土壤微生物的同化作用以及黏土矿物的吸附作用所消耗。两种土壤的硝化作用微弱,BF土壤总硝化速率(以N量计,0.23μg/(g×d))与NF土壤(0.26μg/(g×d))相差不大。两种林地土壤硝化作用均以有机氮的异养硝化为主,自养硝化过程可忽略不计。BF与NF土壤中NO_3~–-N消耗速率均超过了产生速率,表明BF与NF土壤均能有效降低NO_3~–-N的潜在淋失风险,其中BF土壤中NO_3~–-N的消耗以微生物的同化作用为主(58%),而NF土壤以NO_3~–-N异化还原为NH_4~+-N过程为主(68%)。戴云山国家级自然保护区两种亚热带森林土壤的氮转化过程均以NH_4~+-N转化为主,产生的绝大多数NH_4~+-N会迅速通过微生物对NH_4~+-N的同化作用以及黏土矿物对NH_4~+-N的吸附作用固持到有机氮库中;自养硝化过程微弱,使得无机氮主要以NH_4~+-N的形式保存于土壤中,同时酸性土壤环境有效削弱了NH_4~+-N的挥发损失。此外,相对较高的NO_3~–-N微生物同化速率以及异化还原为NH_4~+-N速率,进一步有效降低了NO_3~–-N的淋溶损失以及反硝化作用的气态损失风险,使该地区森林土壤能够在多雨的条件下有效保持氮素,满足植物的生长需求。     

Isolation and identification of sea buckthorn (Hippophae rhamnoides) phenolics with antioxidant activity and α-glucosidase inhibitory effect

This study was performed to evaluate the antioxidant and α-glucosidase inhibitory effects from the extract, fractions, and isolated compounds of sea buckthorn leaves. Six compounds, kaempferol-3-O-β-D-(6'-O-coumaryl) glycoside, 1-feruloyl-β-D-glucopyranoside, isorhamnetin-3-O-glucoside, quercetin 3-O-β-D-glucopyranoside, quercetin 3-O-β-D-glucopyranosyl-7-O-α-L-rhamnopyranoside, and isorhamnetin-3-O-rutinoside, were isolated from sea buckthorn leaf extracts. The butanol fraction (EC(50) = 1.81 μg/mL) along with quercetin 3-O-β-D-glucopyranoside (EC(50) = 1.86 μg/mL) had a higher DPPH radical-scavenging activity and showed stronger reducing power (OD(700) = 1.83 and 1.78, respectively). The butanol fraction (477 mg GAE/g) contained the highest amount of phenolic compounds and also the most powerful α-glucosidase inhibitory effect (86%) at 5 μg/mL. The results indicate that sea buckthorn leaf extracts could potentially be used for food additives and the development of useful natural compounds.     

Anti-inflammatory activities of 6β-acetoxy-7α-hydroxyroyleanone from Taiwania cryptomerioides Hayata ex vivo and in vivo

Excess production of nitric oxide (NO) by inducible NO synthase (iNOS) in activated macrophages is linked to acute and chronic inflammation. Thus, it would be valuable to develop inhibitors of NO production and/or iNOS for potential therapeutic use. This study investigated the anti-inflammatory effects of 6β-acetoxy-7α-hydroxyroyleanone (AHR), a compound isolated from the bark of Taiwania cryptomerioides Hayata, using lipopolysaccharide (LPS)-stimulated mouse macrophage (RAW 264.7) ex vivo and carrageenan (Carr)-induced mouse paw edema model in vivo. When RAW 264.7 macrophages were treated with different concentrations of AHR (0, 0.31, 0.62, 1.25, and 2.50 μg/mL) together with LPS (100 ng/mL), a significant concentration-dependent inhibition of NO production was detected. Western blotting revealed that AHR blocked protein expression of iNOS and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW 264.7 macrophages, significantly. In the anti-inflammatory test, AHR (1.25 and 2.50 mg/kg) decreased paw edema at 4 and 5 h after λ-carrageenan (Carr) administration and increased the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in the liver tissue. It was also demonstrated that AHR significantly attenuated the malondialdehyde (MDA) level in the edema paw at 5 h after Carr injection. AHR (0.62, 1.25, and 2.50 mg/kg) decreased the NO levels on both edema paw and serum at 5 h after Carr injection. Also, AHR diminished the serum tumor necrosis factor (TNF-α) at 5 h after Carr injection. Western blotting revealed that AHR (2.50 mg/kg) decreased Carr-induced iNOS and COX-2 expressions at 5 h in the edema paw. An intraperitoneal (ip) injection treatment with AHR also diminished neutrophil infiltration into sites of inflammation, as did indomethacin (Indo). The anti-inflammatory activities of AHR might be related to the decrease in the levels of MDA, iNOS, and COX-2 in the edema paw and to the increase in the activities of CAT, SOD, and GPx in the liver through the suppression of TNF-α and NO.     

Study of influential factors on oligosaccharide formation by fructosyltransferase activity during stachyose hydrolysis by Pectinex ultra SP-L

The influence of reaction conditions for oligosaccharide synthesis from stachyose using a commercial enzymatic preparation from Aspergillus aculeatus (Pectinex Ultra SP-L) was studied. Oligosaccharides were analyzed by gas chromatography with flame ionization detection (GC-FID) and matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS). Galactosyl-melibiose (DP(3)) was synthesized as a result of fructosidase activity, whereas fructosyl-stachyose (DP(5)) and difructosyl-stachyose (DP(6)) were formed as a consequence of the fructosyltransferase activity of Pectinex Ultra SP-L. The optimal reaction conditions for the synthesis of penta- and hexasaccharides were 60 °C, pH 5.5, 600 mg/mL stachyose, and 34 U/mL enzyme. Reaction time played an important role in oligosaccharide mixture composition constituted by 20% DP(5), 0.7% DP(6), 55% stachyose, 21% galactosyl-melibiose, and 1% monosaccharides after 1 h and 16% DP(5), 4% DP(6), 27% stachyose, 44% galactosyl-melibiose, and 2% monosaccharides after 3 h. In conclusion, stachyose could be used as a substrate for the enzymatic synthesis of new oligosaccharides that may open new opportunities in the development of future prebiotics.     

超顺磁性颗粒表面复合修饰及用于固定化α-淀粉酶载体的效果

磁性Fe_3O_4材料应用于固定化酶具有易分离和回收、操作简便等优点。为保持磁性材料优良的性能,更好的与酶结合,需要对磁性Fe_3O_4纳米颗粒进行修饰。使用低共熔试剂、二氧化硅等材料对制备的超顺磁性Fe_3O_4颗粒进行表面复合修饰,经修饰后的颗粒用于固定化α-淀粉酶,通过透射电子显微镜分析、扫描电镜分析、红外光谱分析、热重分析、综合物性分析、酶活力测定等手段研究了颗粒的结构组成、理化特性。结果表明,载体颗粒呈球形,粒径均在100 nm以下,表面有不规则物,Fe_3O_4纳米颗粒较均匀镶嵌于其中,分散性好。磁性Fe_3O_4纳米颗粒饱和磁化强度为65.42 emu/g,固定化酶后饱和磁化强度仍在21.90 emu/g以上。颗粒表面有丰富的功能基团,且修饰较稳定,其中DES3修饰的复合颗粒酶固载量达145.2μg/(10 mg),且催化活性最高,是良好固定化酶的载体材料。     

Protective effects of fermented filtrate from Antrodia camphorata in submerged culture against CCl4-induced hepatic toxicity in rats

The protective effects and the possible mechanisms of dry matter of fermented filtrate (DMF) from Antrodia camphorata in submerged culture (ACSC) on H(2)O(2)-induced cytotoxicity in HepG2 and carbon tetrachloride (CCl(4))-induced hepatotoxicity in Sprague-Dawley rats were investigated. The results showed that the inhibitory effect of DMF and its crude triterpenoids on lipid peroxidation occurred in a dose-response manner in an AAPH/linoleic acid system. When HepG2 cells were pretreated with DMF at the concentration of 0.10 mg/mL for 4 h and then induced by 1 h of treatment with H(2)O(2) (100 microM), lipid peroxidation was significantly (p < 0.05) decreased, as measured by the formation of malondialdehyde. The oral pretreatment with DMF [0.25 and 0.50 mg/kg of body weight (bw)] for 5 consecutive days prior to the administration of a single dose of 40% CCl(4) (0.10 mL/100 g of bw, ip) significantly prevented the increase in serum levels of hepatic enzyme markers (alanine and aspartate aminotransferase) and liver lipid peroxidation (p < 0.05). Histopathological evaluation of the rat liver revealed that DMF reduced the incidence of liver lesions, including neutrophil infiltration, hydropic swelling, and necrosis induced by CCl(4) in rats. Moreover, reduced glutathione (GSH)-dependent enzymes (glutathione peroxidase, glutathione reductase, and glutathione S-transferase) and the GSH/GSSG ratio were significantly improved in the oral pretreatment DMF of rats (p < 0.01). The results suggest that DMF may play a role in preventing oxidative damage in living systems by up-regulating hepatic GSH-dependent enzymes to preserve the normal GSH/GSSH ratio and scavenging free radicals formed during CCl(4) metabolism.     

Phytochemical changes induced by different nitrogen supply forms and radiation levels in two leafy Brassica species

The effect of three different nitrogen (N) supply forms differing in their ammonium-to-nitrate (NH(4):NO(3)) ratio (100% NH(4), 50% NH(4) + 50% NO(3), 100% NO(3)) under three different levels of daily photosynthetic active radiation (PAR) (low, 5.0; medium, 6.8; high, 9.0 mol m(-2) day(-1)) on a range of desirable health-promoting phytochemicals in Brassica rapa subsp. nipposinica var. chinoleifera and Brassica juncea was determined. The 100% NH(4) supply under medium PAR levels led to the highest concentration of glucosinolates based on a low nitrogen/sulfur ratio as well as high levels of carotenoids in the leaves of both Brassica species. However, the 100% NH(4) supply under low and medium PAR levels resulted in low concentrations of flavonoids based on high N concentration in the leaves. Thus, the data provided here have strong implications for crop management strategies aimed at optimizing both the concentration and composition of a range of phytochemicals.