枸杞硒多糖的合成及对人体肝癌HepG2细胞增殖的体外抑制作用评价

根据有机硒化合物的合成方法,本文以枸杞多糖和亚硒酸钠为原料,采用响应面法优化枸杞硒多糖的工艺条件。利用原子荧光、体外化学反应等分析技术测定了枸杞硒多糖中的硒含量,并用MTT法对枸杞硒多糖抑制人体肝癌细胞增殖的活性进行了初步评价。结果表明:制备枸杞硒多糖的最优条件是按照LBP为1 g计算,加入0.62 g Na₂SeO₃,用1% HNO₃充分溶解,再加入BaCl₂ 1 g,74 ℃反应9 h。在此条件下,枸杞硒多糖中的硒含量为648.65 μg/g。活性结果显示,枸杞多糖和枸杞硒多糖对HepG2细胞均有一定的抑制作用,所有枸杞硒多糖的抑制作用明显优于枸杞多糖,并且硒含量最高的Se-LBP₄组对肿瘤细胞HepG2的抑制效果最佳,抑制率为38.15%。枸杞硒多糖抑制HepG2增殖能力与其硒的含量呈正相关,有望作为食品、保健食品和医药的原料进一步开发。     

微生物转化法制备纳米硒及有机硒的研究进展

硒是人体必需的微量元素之一,是许多重要酶的活性中心,人体硒缺乏可能会引起多种疾病的产生。自然界中,硒元素主要以亚硒酸盐(Se⁴⁺)、硒酸盐(Se⁶⁺)的形式存在,无机硒具有较强的细胞毒性,难以被人体吸收,安全剂量范围较窄,利用微生物制备的纳米硒和有机硒具有较高的生物活性、较低的毒性,易于吸收,安全、高效、环保等优势。目前,利用微生物转化无机硒制备的纳米硒和有机硒的应用越来越广。文章主要综述了微生物制备纳米硒和有机硒的微生物种类、所制备的纳米硒及有机硒的表征方法与检测技术、相关转化机制以及在各领域的应用介绍,为微生物制备纳米硒及有机硒的研究应用提供理论支撑。     

紫阳富硒茶对人肝癌细胞凋亡过程的诱导

通过运用倒置荧光显微镜和流式细胞仪观察和测定细胞形态、周期、和凋亡率的变化,从而分析紫阳富硒茶对人肝癌细胞增殖的抑制作用及其诱导凋亡途径。结果表明：紫阳富硒茶能抑制人肝癌细胞的生长,并诱导人肝癌细胞凋亡;同时随着紫阳富硒茶质量分数的增加,人肝癌细胞形态发生明显变化,细胞周期被阻滞在S期,细胞凋亡率显著增加。试验表明紫阳富硒茶能抑制人肝癌细胞增殖,通过阻滞细胞周期从而诱导细胞凋亡。     

硒化猴头菇多糖的制备、结构表征及抗增殖活性

以猴头菇纯化多糖（Hericium erinaceus polysaccharide,HEPS）（总糖含量＞92%）为研究对象,在含有VC和亚硒酸钠的氧化还原体系中,制备得到猴头菇多糖纳米硒复合物（HEPS-Se）。通过原子吸收分光光谱仪、傅里叶变换红外光谱仪、X射线衍射仪、扫描电子显微镜、EDX元素分析仪、X射线光电子能谱、纳米粒度仪等对其结构进行表征;同时研究HEPS-Se对人肺癌细胞A549、人前列腺癌细胞DU145的抗增殖作用。结果表明：所制备的HEPS-Se为形貌规则、均一的球体,其元素组成比例为C∶O∶Se∶Pt＝32.92∶24.74∶30.46∶11.87;其中Se元素的含量高达481.79 μg/g。傅里叶变换红外光谱表明HEPS主要通过—OH、—C＝O等基团与纳米硒结合。与HEPS相比,HEPS-Se的粒径显著降低,电位绝对值提高了69.12%。同时,体外抗增殖活性结果表明,HEPS-Se能显著抑制人前列腺癌细胞DU145、人肺癌细胞A549的增值活性,并呈现明显的剂量效应。本研究为有机硒补充剂的开发提供良好的理论依据。     

醋酸催化下枸杞多糖的硒化修饰及抗肿瘤活性

制备硒化枸杞多糖,初步了解其结构及体外抗肿瘤活性。利用亚硒酸钠对枸杞多糖进行修饰,通过将无机硒转化为有机硒,为得到高含硒量的枸杞多糖进行探索,找出最佳反应条件为:2mL冰醋酸作为催化试剂,硒化试剂硒酸钠用量为2g,室温下反应时间48h。通过紫外光谱、红外光谱分析,并进行了体外抗肿瘤的初步试验研究。结果:确定了硒化枸杞多糖的分子结构中存在亚硒酸基团,人宫颈癌细胞抑制率可达到26.1%。硒化枸杞多糖对人宫颈癌细胞存在一定的抑制作用。     

亚硒酸钠在SGC-7901细胞生长中的抑制作用

目的：研究亚硒酸钠对SGC-7901细胞生长的影响。方法：应用细胞培养和SRB实验探讨了亚硒酸钠对SGC-7901细胞生长曲线的影响：应用集落形成试验、分裂指数试验研究了亚硒酸钠对SGC-7901细胞集落形成和分裂指数的影响；应用流式细胞仪检测了亚硒酸钠对SGC-7901细胞生长周期的影响；应用电镜、TUNEL染色及流式细胞仪观察了亚硒酸钠诱导SGC-7901细胞凋亡的作用。结果：亚硒酸钠溶液对SGC-7901细胞的生长曲线、集落形成、分裂指数有明显的抑制作用，其抑制作用与其作用浓度和作用时间呈正相关。流式细胞仪检测显示亚硒酸钠作用SGC-7901细胞24h后，细胞周期发生改变，G1期细胞百分率减少，S期细胞百分率增加，与对照组相比有显著性差异（p〈0．05）：电镜下，细胞核固缩，染色质凝集呈新月形紧贴于核膜周边，核膜扭曲；DNA直方图上出现典型的亚二倍体的“凋亡峰”；TUNEL染色法检测细胞凋亡指数在10．4％～33．4％。结论：亚硒酸钠溶液对SGC-7901细胞的生长具有抑制作用，其抑制作用程度与其作用浓度和时间呈正相关：亚硒酸钠通过阻滞细胞S期抑制细胞增殖及诱导细胞凋亡可能是其抑制SGC-7901细胞生长的机理之一。     

烟叶硒蛋白质工业化提取及其对免疫调节和抗氧化作用的影响

鲜烟叶经喷施亚硒酸钠处理,提取得到硒蛋白质。硒蛋白质相对于鲜叶的工业提取率为1‰,含酒量为1500μg/g。硒蛋白质溶液制剂使老年小鼠淋巴细胞增殖反应、NK细胞活性、血清凝集素水平、吞噬率和吞噬指数均显著提高。硒蛋白质溶液制剂显著提高大鼠血清GSHPx活性,显著降低大鼠血清MDA含量。烟叶硒蛋白质具有免疫调节和抗氧化作用。      

雪莲菌富硒条件优化及体外抗氧化活性分析

利用雪莲菌吸收和转化无机硒为有机硒,旨在通过优化富硒条件制备菌活性和有机硒占比较高的富硒雪莲菌。针对不同优化需求,确定不同优化指标,从而选择最佳的富硒条件。优化后富硒温度为28 ℃、富硒时间为24 h、亚硒酸钠添加时间为雪莲菌接种后3 h;通过摇床培养,进行梯度驯化富硒;以透析后总硒含量占比、生物量、富硒率（selenium enrichment rate,SER）和有机硒占比（organic selenium percentage,OSP）确定梯度富硒底物浓度为3、6、9、12、15 μg/mL。在最优富硒条件下所制备的富硒雪莲菌的总硒含量（total selenium content,TSC）为（2 194.41±58.49）μg/g,有机硒占比为（84.57±1.45）%。通过抗氧化活性测定发现富硒雪莲菌的抗氧化活性极显著高于雪莲菌（P＜0.001）。     

黑木耳β-葡聚糖/纳米硒复合物（DNT-Se）的制备工艺优化及活性评价

探索黑木耳β-葡聚糖/纳米硒复合物(DNT-Se)的最佳制备条件，并探究其安全性。以多糖(DNTs)浓度、维生素C(VC)与亚硒酸钠配比、亚硒酸钠浓度、反应时间、反应温度作为实验因素，采用双波长比色法及马尔文粒径测定法表征DNT-Se中Se NPs的粒径变化，以Se NPs的粒径大小为评价指标，采用单因素及正交试验设计的方法考察DNT-Se的制备工艺，并采用CCK-8法评价DNT-Se对293T人胚胎肾细胞和AML-12小鼠正常肝细胞的毒性。DNTs浓度1.0 mg/mL，维生素C与亚硒酸钠配比为6:1，亚硒酸钠浓度为1.0 mg/mL、反应时间12 h、反应温度25℃为制备DNT-Se的最佳条件。该条件下制备的DNT-Se中Se NPs的粒径大小均值为34.50 nm，细胞增殖实验结果表明，DNT-Se对293T人胚胎肾细胞和AML-12小鼠正常肝细胞在200μg/mL时细胞存活率仍高于82%，同时DNT-Se能够抑制HepG2细胞的增殖，在72 h时对HepG2细胞的IC₅₀值为42.54μg/mL。本研究成功确定了DNT-Se的最优制备工艺，所得纳米硒粒径较...     

富硒豌豆苗粉理化性质及抗氧化活性分析

本实验以富硒豌豆苗为研究对象,利用热风干燥和冷冻干燥进行处理,通过化学分析及色差分析、微观结构观察、低场核磁共振分析等探究不同制备工艺对豌豆苗粉有机硒含量损失率、豌豆苗粉色度、表观形貌、水分分布及体外抗氧化活性等的影响规律。结果表明：100℃热风干燥制备的富硒豌豆苗粉的品质较为理想,其有机硒损失率较小(36.7%)、色泽良好;富硒豌豆苗粉表观形貌呈现块状颗粒,表面褶皱程度及纤维管束明显增多;经热风干燥制备的富硒与未富硒豌豆苗粉中水分分布情况存在显著差异。与未富硒豌豆苗粉相比,富硒豌豆苗粉乙醇提取液1,1-二苯基-2-三硝基苯肼自由基清除能力(半抑制浓度(half maximal inhibitory concentration,IC₅₀)=0.61 mg/mL)、羟自由基清除能力(IC₅₀=0.86 mg/mL)、超氧阴离子自由基清除能力(IC₅₀=0.90 mg/mL)以及铁离子还原力(吸光度为0.30)显著提高(P<0.01)。本研究结果可为有机硒天然食品补充剂开发及富硒食品产业化提供一定的理论指导与技术参考。     

Factors affecting soluble selenium removal by a selenate-reducing bacterium Bacillus sp. SF-1

High concentrations of soluble selenium, selenate and selenite, have acute and chronic toxicity toward living things. With the aim of developing a biological process for selenium removal, the effects of a variety of parameters on the reduction of soluble selenium by a Bacillus sp. strain SF-1, which is capable of reductively transforming selenate into selenite and, subsequently, into nontoxic insoluble elemental selenium, were studied. The bacterial strain could effectively reduce 20 mM of selenate to selenite and 2 mM of selenite to elemental selenium in the presence of an appropriate carbon source and in the absence of oxygen. The reduction rate of selenate to selenite was much higher than that of selenite to elemental selenium, resulting in the transient accumulation of selenite during selenate reduction. The selenate reduction rate increased with increases in the selenate concentration up to 20 mM, while the rate of selenite reduction decreased sharply at selenite concentrations of more than 2 mM. The elemental selenium transformed from selenate via selenite was found both inside and outside the cells. Bacillus sp. SF-1 was able to utilize a variety of organic acids or sugars as a carbon source in selenate reduction. Although the copresence of sulfate did not inhibit selenate reduction, it was completely inhibited by some other oxyanions, including nitrate. A model sequencing batch system using the bacterial strain was developed and exhibited good performance in the treatment of wastewater containing high concentrations of selenate.     

Factors affecting soluble selenium removal by a selenate-reducing bacterium Bacillus sp. SF-1

High concentrations of soluble selenium, selenate and selenite, have acute and chronic toxicity toward living things. With the aim of developing a biological process for selenium removal, the effects of a variety of parameters on the reduction of soluble selenium by a Bacillus sp. strain SF-1, which is capable of reductively transforming selenate into selenite and, subsequently, into nontoxic insoluble elemental selenium, were studied. The bacterial strain could effectively reduce 20 mM of selenate to selenite and 2 mM of selenite to elemental selenium in the presence of an appropriate carbon source and in the absence of oxygen. The reduction rate of selenate to selenite was much higher than that of selenite to elemental selenium, resulting in the transient accumulation of selenite during selenate reduction. The selenate reduction rate increased with increases in the selenate concentration up to 20 mM, while the rate of selenite reduction decreased sharply at selenite concentrations of more than 2 mM. The elemental selenium transformed from selenate via selenite was found both inside and outside the cells. Bacillus sp. SF-1 was able to utilize a variety of organic acids or sugars as a carbon source in selenate reduction. Although the copresence of sulfate did not inhibit selenate reduction, it was completely inhibited by some other oxyanions, including nitrate. A model sequencing batch system using the bacterial strain was developed and exhibited good performance in the treatment of wastewater containing high concentrations of selenate.     

烟株对不同价态硒的吸收与分配

为了开发富硒烟叶生产技术和了解烟叶对硒的富集机理,采用水溶性Se（Ⅳ）（亚硒酸钠）和Se（Ⅵ）（硒酸钠）盆栽试验,探讨了烟株对硒的吸收和分配规律,以及不同价态和用量的硒对烟株生长发育的影响。结果表明,土壤施用适当浓度的两种价态硒（1～10 mg/kg）均有改善烟株形态性状和提高生物量的作用,高浓度硒（20～30 mg/kg）则有负面影响,且Se（Ⅵ）处理抑制效果大于 Se（Ⅳ）。相同浓度下,两种价态的硒均能有效提高烟株各部位硒含量,Se（Ⅵ）处理较 Se（Ⅳ）提高了3～30倍。土壤中的硒优先富集和分布于叶片中,其次是根系,茎秆最小。Monod方程拟合结果表明,Se（Ⅵ）处理烟株叶片、茎秆和根系最大硒含量分别是Se（Ⅳ）处理的1.83、15.81和20.98倍,烟株对Se（Ⅵ）的亲和能力显著大于Se（Ⅳ）,说明Se（Ⅵ）对烟株的生物有效性明显高于Se（Ⅳ）。     

Release of reduced inorganic selenium species into waters by the green fresh water algae Chlorella vulgaris

The common green fresh water algae Chlorella vulgaris was exposed to starting concentrations of 10 μg/L selenium in the form of selenate, selenite, or selenocyanate (SeCN(-)) for nine days in 10% Bold's basal medium. Uptake of selenate was more pronounced than that of selenite, and there was very little uptake of selenocyanate. Upon uptake of selenate, significant quantities of selenite and selenocyanate were produced by the algae and released back into the growth medium; no selenocyanate was released after selenite uptake. Release of the reduced metabolites after selenate exposure appeared to coincide with increasing esterase activity in solution, indicating that cell death (lysis) was the primary emission pathway. This is the first observation of biotic formation of selenocyanate and its release into waters from a nonindustrial source. The potential environmental implications of this laboratory observation are discussed with respect to the fate of selenium in impacted aquatic systems, the ecotoxicology of selenium bioaccumulation, and the interpretation of environmental selenium speciation data generated, using methods incapable of positively identifying reduced inorganic selenium species, such as selenocyanate.     

沪酿3.042米曲霉富硒条件的探索

目的：探索沪酿3．042米曲霉的富硒能力并找到最佳的富硒条件。方法：于豆芽汁液体培养基中添加一系列浓度的亚硒酸钠，培养一段时间，研究亚硒酸钠浓度对米曲霉生物量、富硒能力，蛋白酶活力的影响，找到适合的亚硒酸钠浓度，测定此浓度下米曲霉的生长曲线、富硒量曲线，找到最佳的富硒条件，分析此条件下富硒米曲霉胞内硒的存在状态。结果：亚硒酸钠浓度为100mg／L时米曲霉的生物量最大，富硒能力最高，50mL液体培养基可以收获0．454g湿茵体，含有胞内硒2mg，其中有机硒含量达到95％以上，最适合的茵体收获时间是48h。但是此时蛋白酶活力降低明显，亚硒酸钠浓度为50mg／L时蛋白酶活力比不加亚硒酸钠时活力更高，36h达到活力峰，此时富硒能力也较强。结论：米曲霉是个很好的富硒载体，亚硒酸钠浓度为100mg／L时富硒能力最高，应用前景很好。     

Characterization of Pseudomonas stutzeri NT-I capable of removing soluble selenium from the aqueous phase under aerobic conditions

Pseudomonas stutzeri strain NT-I was isolated from the drainage wastewater of a selenium refinery plant. This bacterium efficiently reduced selenate to elemental selenium without prolonged accumulation of selenite under aerobic conditions. Strain NT-I was able to reduce selenate completely at high concentrations (up to 10 mM) and selenite almost completely (up to 9 mM). In addition, higher concentrations of selenate and selenite were substantially reduced. Activity was observed under the following experimental conditions: 20–50°C, pH 7–9, and 0.05–20 g L^–1 NaCl for selenate reduction, and 20–50°C, pH 6–9, and 0.05–50 g L^–1 NaCl for selenite reduction. Under anaerobic conditions, selenate was reduced more rapidly, whereas selenite was not reduced at all. The high selenate- and selenite-reducing capability at high concentrations suggested that strain NT-I is suitable for the removal of selenium from high-strength industrial wastewater.     

富硒青钱柳多糖对α葡萄糖苷酶及HepG2细胞葡萄糖消耗的影响

以α-葡萄糖苷酶和HepG2细胞作为体外受体模型,研究富硒青钱柳多糖(Se-CPP)体外降血糖活性,并与青钱柳多糖(CPP)、CPP+硒酵母、CPP+亚硒酸钠复配物比较。结果表明,Se-CPP对α-葡萄糖苷酶活性具有良好的抑制效果且呈现明显的剂量依赖性,其半抑制浓度(IC₅₀)为0.054 mg/mL,低于阿卡波糖、CPP、CPP+硒酵母、CPP+亚硒酸钠复配物。适宜浓度的Se-CPP可促进胰岛素抵抗状态HepG2细胞对葡萄糖的消耗,效果显著优于CPP、CPP+硒酵母、CPP+亚硒酸钠复配物(p<0.05)。     

Combined speciation analysis by X-ray absorption near-edge structure spectroscopy, ion chromatography, and solid-phase microextraction gas chromatography-mass spectrometry to evaluate biotreatment of concentrated selenium wastewaters

In this study we evaluate the potential of anaerobic granular sludge as an inoculum for the bioremediation of selenium-contaminated waters using species-specific analytical methods. Solid species formed by microbial reduction were investigated using X-ray absorption near-edge structure (XANES) spectroscopy at the selenium K-edge. Furthermore, dissolved selenium species were specifically determined by ion chromatography (IC) and solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS). Least-squares linear combination of the XANES spectra for samples incubated with the highest selenate/selenite concentrations (10(-3) M) show the predominance of elemental selenium and a Se(-I) selenide, such as ferroselite, the thermodynamically most stable iron selenide. In contrast, elemental selenium and Se(-II) selenides are the main species detected at the lower selenate/selenite concentrations. In each repeated fed batch incubation, most aqueous selenite anions were converted into solid selenium species, regardless of the type of electron donor used (acetate or H(2)/CO(2)) and the selenium concentration applied. On the other hand, at higher concentrations of selenate (10(-4) and 10(-3) M), significant amounts of the oxyanion remained unconverted after consecutive incubations. SPME-GC-MS demonstrated selenium alkylation with both electron donors investigated, as dimethyl selenide (DMSe) and dimethyl diselenide (DMDSe). Selenite was even more alkylated in the presence of H(2)/CO(2) (maximum 2156 μg of Se/L of DMSe + DMDSe) as compared to acetate (maximum 50 μg of Se/L). In contrast, selenate was less alkylated using both electron donors (maximum 166 and 3 μg of Se/L, respectively). The high alkylation potential for selenite limits its bioremediation in selenium laden waters involving H(2)/CO(2) as the electron donor despite the fact that nontoxic elemental selenium and thermodynamically stable metal selenide species are formed.     

石榴皮多糖硒酸酯制备工艺参数优化及其结构分析

以石榴皮多糖与亚硒酸钠为原料制备石榴皮多糖硒酸酯,以产物硒含量和收率为指标,原料配比、硝酸体积分数、反应温度和反应时间为单因素,通过单因素试验和Box-Behnken试验设计方法对工艺条件进行优化,并对产物结构进行分析。结果显示：石榴皮多糖硒酸酯最佳制备工艺条件为原料配比1∶1.0（g/g）、硝酸体积分数0.61%、反应温度77.0 ℃、反应时间11.3 h,在该工艺条件下,制得石榴皮多糖硒酸酯中硒含量为4.48 mg/g,产物收率为41.87%;紫外光谱、红外光谱和热重分析充分证实石榴皮多糖硒酸酯中含有Se＝O键、Se-O键和Se-C键。优化后的石榴皮多糖硒酸酯制备工艺条件实现了石榴皮多糖的硒化,为石榴皮资源的充分开发利用提供良好条件。     

Dietary selenium reduces retention of methyl mercury in freshwater fish

Adverse effects from organic mercury transported along aquatic food chains are health issues in humans and other top predators. Methyl mercury in organisms at the lower food chain levels is eliminated slowly, and laboratory studies have not clarified the role of selenium in the retention of methyl mercury in fish. Here, we investigated the effects of dietary selenium on the retention of organic and inorganic mercury in freshwater fish. Addition of selenite to the food augmented elimination of methyl mercury (but not inorganic mercury) from goldfish Carassius auratus in a dose dependent manner; selenite caused methyl mercury to be lost from the general body rather than from any specific organ. Seleno-cystine and seleno-methionine (but not selenate) likewise promoted elimination of methyl mercury from goldfish. The threshold for the augmenting effect of selenite on the elimination of methyl mercury in the zebra fish Danio rerio was 0.95 μg Se g(-1) food; higher concentrations reduced retention of methyl mercury in a dose dependent manner. Selenium concentrations in the food approaching natural background levels increase the elimination of methyl mercury from fish. Thus, selenium levels in a given aquatic food chain may affect mercury contamination along the food chain.