硼对盐藻生长与物质积累的调控作用

实验研究了不同浓度的硼对盐藻细胞生长与物质积累的调控作用.结果表明,培养液中供给硼过多或过少都不利于盐藻细胞的生长与物质积累.以培养基中4 mg/L的硼浓度对盐藻细胞生长、蛋白质合成与β-胡萝卜素积累的促进作用最大.这一硼浓度可用于盐藻的生产性培养.当培养液中硼浓度较高(8 mg/L)或较低(2 mg/L)时,单个盐藻细胞中的蛋白质与β-胡萝卜素含量较高.但此时,因培养液中细胞密度较低,盐藻细胞积累的物质总量仍然较少.在硼浓度较高或较低的逆境条件下,盐藻可能通过适应性反应形成了逆境蛋白质与胡萝卜素等.     

钼对盐藻生长与物质积累的调控作用

实验研究了不同浓度的钼对盐藻细胞生长物质积累的调控作用.结果表明,培养液中供给钼过多或过少都不利于盐藻细胞的生长与物质积累.以培养基中60μg/L的钼浓度对盐藻细胞生长、蛋白质合成与β-胡萝卜素积累的促进作用最大.这一钼浓度可用于盐藻的生产性培养.当培养液中钼浓度较高(80μg/L)或较低(20μg/L)时,单个盐藻细胞中的蛋白质与β-胡萝卜素含量较高.但此时,因培养液中细胞密度较低,盐藻细胞积累的物质总量仍然较少.在钼浓度较高或较低的逆境条件下,盐藻可能通过适应性反应形成了逆境蛋白质与胡萝卜素等.     

盐藻培养基的优化研究

本文利用生物量和TTC为检测指标,从四种盐藻培养基中筛选了一种较适和盐藻(Dunaliellasalina)生长的培养基,并对该培养基的N、P、Fe和NaCl组成进行了单因素和正交优化,使藻的生物量提高了1.2倍,为从盐藻中获取生物活性物质提供了原料。     

广盐性硅藻披针舟形藻在高盐和低盐胁迫下的抗氧化响应

有关藻类耐盐的抗氧化响应机制的研究报道很少,披针舟形藻(Navicula lanceolata)是从盐场分离到的广盐性硅藻,文章研究了其在长期高盐及低盐胁迫下的抗氧化响应.与对照组(1.6% NaCl)相比,在低盐(0%,0.5%,0.8%,1.0%NaCl)及高盐(3.2%,4.8%,6.4%,8.0%,9.6%NaCl)胁迫条件下,披针舟形藻的生长受到抑制,胞内膜氧化产物丙二醛的含量显著升高,表明藻细胞内出现了氧化损伤.在高盐及低盐胁迫下,胞内的抗氧化酶超氧化物歧化酶、抗坏血酸过氧化物酶、过氧化氢酶和谷胱甘肽还原酶的活性均增强,非酶抗氧化剂抗坏血酸和还原型谷胱甘肽含量均增加.上述研究结果显示,披针舟形藻通过提高抗氧化酶的活性及非酶抗氧化剂的含量来应对长期盐胁迫下的氧化损伤,细胞抗氧化系统的响应是藻耐受长期盐胁迫的机制之一.     

极端嗜盐绿色杜氏藻培养技术的研究

极端嗜盐环境下生长的绿色杜氏藻(D.viridis)具有较为独特的生物特性,具有一定的应用价值和开发前景。文章着重研究了极端嗜盐绿色杜氏藻生长所需条件,内容包括培养液碳源、盐度、营养盐、pH值。并探讨了极端嗜盐绿色杜氏藻的人工培养技术。     

拉曼光谱技术检测苹果表面残留的敌百虫农药

建立苹果表面残留的敌百虫农药的拉曼光谱无损检测技术。方法 利用激光显微拉曼光谱技术, 以苹果为载体, 敌百虫农药为研究对象, 探讨苹果表面敌百虫农药的快速无损检测方法。结果 敌百虫农药的拉曼特征频率较为丰富, 选取441 cm?1 (P-O键振动)和620 cm?1(C-Cl键振动)处的拉曼信号可识别苹果表面敌百虫农药残留, 检测限为4800 mg/kg。结论 本研究对实现水果表面敌百虫农药残留的快速、无损伤检测具有重要意义。     

硝酸盐对盐藻生长与物质积累的调控作用

文章报道不同浓度的硝酸盐对盐藻细胞生长与物质积累的调控作用.实验表明,增加氮的供给可促进盐藻的物质合成与生长发育.培养液中不供给氮时,虽然单个盐藻细胞内的蛋白质与β-胡萝卜素含量较高,但盐藻细胞生长受到抑制,使藻液中细胞密度降低,蛋白质与β-胡萝卜素的合成减少,不利于盐藻蛋白质和β-胡萝卜素的积累与利用.极度缺氮时,单个盐藻细胞内的蛋白质与β-胡萝卜素含量较高,可能是盐藻对逆境的一种适应.     

盐藻工厂化养殖技术与产品开发(一)

盐藻是一种光能转化率高、生产繁殖快、适于养殖的单细胞藻.从养殖地域的选择、藻种的选育、培养介质、室外养殖设施、培养方式、培养条件的控制、敌害防治及采收等方面对盐藻的工厂化养殖技术做了全面介绍.在产品开发方面,介绍了盐藻粉的营养成分和氨基酸组成,介绍了盐藻粉软胶囊的三项功能试验结果,试验结果表明盐藻粉具有抗辐射、调节免疫和抑制肿瘤的作用;还对盐藻胡萝卜素的几种产品形式及营养评价做了简要介绍.最后,对盐藻工厂化养殖中存在的问题做了简要讨论,对盐藻胡萝卜素产业的发展前景做了展望.     

海洋微藻总脂含量和脂肪酸组成的测定

对14株海洋微藻(绿藻纲6株,金藻纲4株,硅藻纲3株,甲藻纲1株)中的总脂含量和脂肪酸成分进行了测定.结果表明,14株海洋微藻的总脂含量存在着明显差异,盐藻的总脂含量最高,占干重的28.71%;4株金藻的总脂含量均较高,超过干重的20%.14株海洋微藻的脂肪酸成分和含量也存在着较大的差异,绿藻中饱和脂肪酸C16:0的含量均较高;对于单不饱和脂肪酸,小球藻以C16:1(n-7)为主,盐藻以C18:1(n-7)为主,青岛大扁藻以C18:1(n-9)为主.4株金藻的PUFAs含量均较高,几乎占脂肪酸总量的1/2,并且DHA的含量较其他藻株高.3株硅藻的EPA含量最高,占27.2%～32.9%;而裸甲藻的PUFAs含量最低,仅为25.2%.     

杜氏盐藻β-胡萝卜素提取皂化工艺参数优化

以甲醇-丙酮(20∶80,V/V)为流动相,建立杜氏盐藻β-胡萝卜素HPLC-DAD检测方法。采用外标法定量,对杜氏盐藻β-胡萝卜素的提取皂化工艺参数进行优化。研究结果表明,所选6种溶剂中,95%乙醇的提取效果最好。对选取的杜氏盐藻粉皂化,使胡萝卜素的得率从0.350%提高到0.425%,提高了21.43%。优化提取的最佳工艺参数是:提取温度25℃、时间0.7 h、液固比200 m L/g。此条件下杜氏盐藻β-胡萝卜素得率为0.395%。皂化的最佳工艺参数是:皂化温度25℃、皂化时间2 h、KOH甲醇溶液质量浓度0.1 g/m L。采用此提取皂化工艺,杜氏盐藻β-胡萝卜素的最终得率为0.428%。     

NaNO3对两种杜氏藻生长及色素积累的影响

研究NaNO3对两种杜氏藻Dunaliella salina和Dunaliella parva生长速度、色素积累的影响和NaNO3的吸收规律。结果表明,NaNO3浓度为1.5 mmol/L时,D.salina生长最快,最高密度76.4×104cell/mL;对照组为16.3×104cell/mL;低氮有利于D.salinaβ-胡萝卜素积累,β-胡萝卜素最大值105 mg/g出现在0.5 mmol/L NaNO3样中,对照组为45 mg/g;较高的NaNO3有利于叶绿素a的合成;藻液pH开始3 d~5 d急剧上升,后在波动中下降。对D.parva来说,NaNO3浓度为2.5 mmol/L时生长最快,细胞最高密度为295×104cell/mL,对照组为15×104cell/mL;在实验范围内,NaNO3浓度越高,β-胡萝卜素含量越高,β-胡萝卜素最大值为37.5 mg/g,叶绿素最大值为65 mg/g;建立了两种杜氏藻对NaNO3利用的动力学方程。     

盐藻的紫外诱变及优势藻株的初步筛选

通过紫外诱变技术筛选具有优良性状的盐生杜氏藻（Dunaliella salina）株系,以期通过紫外诱变提高盐藻的生长速率、β-胡萝卜素含量、蛋白质和胞外多糖含量。紫外诱变后,筛选出4株与出发株相比具有生长优势的藻株,在培养一周后,4个株系的最终细胞密度分别达到1.32×10^6cell/ml、1.49×10^6cell/ml、1.63×10^6cell/ml、1.54×10^6cell/ml,比出发株的最终细胞密度1.12×10^6cell/ml分别提高了17.86%、33.04%、45.54%、37.50%。测定了这4个株系的β-胡萝卜素、蛋白质和胞外多糖含量,结果显示,有2株藻种的β-胡萝卜素含量有显著提高,β-萝卜素含量为9.81mg/L、10.21mg/L,与出发株（7.86mg/L）相比分别提高了24.8%和29.90%;胞外多糖含量有所增加,有3株藻种胞外多糖含量分别由出发株的43mg/L增加到51mg/L、45mg/L、47mg/L,增幅分别为18.60%、4.65%、9.30%;而盐藻的蛋白质含量经紫外线照射后,与出发株相比呈下降趋势。     

Effects of prepartum supplementation of β-carotene in Holstein cows

Whether supplemental dietary β-carotene affects periparturient cows and vitamins A and E in cows when dietary vitamin A is adequate remains uncertain. Our objective was to assess the effect of β-carotene supplementation during the close-up dry period in a herd with adequate status of vitamins A and E but low in β-carotene. The study was conducted on a large commercial dairy farm in Indiana during early summer of 2015. Ninety-four multiparous Holstein cows were assigned to either control (CON; n = 47) or β-carotene (BC; n = 47) treatments. When locked in headgates each morning, each cow received a topdress of β-carotene (Rovimix, 8 g/d; provided 800 mg of β-carotene) or carrier from 21 d before expected calving until calving. Blood samples were collected at 21 ± 1 d (mean ± standard deviation) before expected calving (before treatments began), 7 ± 1 d before calving, immediately following parturition, and 7 ± 1 d postpartum. Blood serum was analyzed for vitamins A and E, β-carotene, cholesterol, and other metabolites and enzymes. Data were analyzed using the MIXED procedure in SAS (SAS Institute Inc.). Cows had low β-carotene concentrations (0.85 μg/mL) in blood serum before treatments began. Compared with CON cows, BC cows had higher overall mean concentrations of β-carotene (2.87 μg/mL vs. 0.73 μg/mL) and retinol (165 vs. 143 ng/mL). Cows fed BC had lower α-tocopherol in serum than cows fed CON (2.26 vs. 2.46 µg/mL). Cows fed BC had lower peak milk than cows fed CON (50.9 vs. 55.3), but total lactation milk yield did not differ significantly. No effects of BC were observed on days to conception (100 d) or times bred (2.4). Treatments did not affect incidences of ketosis, retained placenta, displaced abomasum, off feed, lameness, footrot, mastitis, or metritis. In conclusion, in pregnant cows already receiving adequate vitamin A but with low serum β-carotene concentration, supplementation of β-carotene increased concentrations of β-carotene and vitamin A in blood serum, but did not affect production, reproduction, or health.     

β-胡萝卜素对H2O2诱导的斑马鱼肝损伤的保护作用

研究β-胡萝卜素对H2O2诱导的斑马鱼肝损伤的保护作用。选择适宜浓度的H2O2诱导斑马鱼肝脏氧化应激损伤,分别以5、10、20 μg/mL的β-胡萝卜素对其进行保护。给药48 h后检测组织匀浆中谷丙转氨酶（alanine aminotransferase,ALT）、谷草转氨酶（aspartate aminotransferase,AST）、超氧化物歧化酶（superoxide dismutase,SOD）活力和丙二醛（malondialdelyde,MDA）含量;苏木精-伊红染色观察斑马鱼肝组织病理变化情况;实时荧光定量聚合酶链式反应技术检测SOD、CAT和GSTP2以及核转录因子Nrf2 mRNA的相对表达量。结果表明：H2O2处理斑马鱼仔鱼48 h后,组织匀浆液中ALT和AST活力升高,SOD活力降低,MDA含量升高;与模型组比较,β-胡萝卜素能够抑制ALT和AST的升高,提高SOD活力,降低MDA含量;病理切片结果显示β-胡萝卜素组能显著改善斑马鱼肝脏组织病理形态;提高Nrf2 mRNA的相对表达量,上调抗氧化酶基因的相对表达量。β-胡萝卜素对H2O2诱导的斑马鱼肝损伤具有保护作用。     

分阶段温度控制策略提高重组葡萄酒酵母合成β-胡萝卜素的研究

利用农副产品为发酵底物,生产高附加值的牛物产品具有良好的应用前景。本研究以模拟葡萄汁为培养基,在7L发酵罐水平L研究了不同发酵温度（25℃、27℃、30℃、33℃）重组葡萄酒酵母T73-63生长和合成外源B．胡萝b素的情况。结果发现,重组葡萄酒酵母最适牛长温度与β-胡萝b素最适合成温度是不一致的：较高的发酵温度（30℃）有利于细胞的生长,能够获得较高的牛物量;但较低的温度（25qc）却能够获得较高的比产物合成速率。根据细胞生长和产物合成动力学曲线,提出了两阶段温度控制策略：发酵前20h温度控制为30℃,20h后降低至25℃至发酵结束;在此调控策略下,最高β-胡萝b素产量和β-胡萝b素合成速率分别达到56．42mg／L和1．28rag／（L．h）,与单一温度发酵模式的最高水平（30℃）相比分别提高了25．7％和14．3％。     

Cr^3＋对盐藻生长的影响及其在细胞中的富集和分布

本文研究了Cr^3＋对盐藻生长和细胞形态的影响,并对其在盐藻中的富集和在盐藻主要大分子化合物中的分布进行了探索和分析。结果表明,低浓度的Cr3＋促进盐藻的生长,而高浓度的Cr^3＋对其生长产生抑制作用,并对盐藻细胞形态产生不良影响。CrCl3·6H2O浓度为2mg/L时,Cr^3＋对盐藻生长和Cr^3＋富集均产生促进作用,其富集量达到779.64μg/g,富集率达到85.27%。实验结果还表明,铬跟盐藻中主要大分子化合物都有结合作用,而且主要与多糖结合。     

Effects of prepartum supplementation of β-carotene on colostrum and calves

Little is known about transfer of dietary β-carotene into colostrum, its absorption by the calf, and its effects on retinol and α-tocopherol in the calf when the dam's dietary vitamin A is adequate. Our objective was to assess the effect of β-carotene supplementation during the close-up dry period on the colostrum and calf. The study was conducted on a large commercial dairy farm in Indiana during early summer of 2015. Ninety-four multiparous Holstein cows were blocked by calving data, parity, and previous production, and then randomly assigned to either control or β-carotene (BC) treatments. While locked in headgates each morning, each cow received a topdress of β-carotene (Rovimix, DSM Nutritional Products, 8 g/d; provided 800 mg β-carotene) or carrier from 21 d before expected calving until calving. Colostrum was collected within 2 h of parturition. Calf blood samples were obtained within 2 h of birth before receiving the dam's colostrum, at 24 h after birth, and at 7 d and 60 d of age. Blood serum was analyzed for β-carotene, retinol, α-tocopherol, and other metabolites and enzymes. Colostrum was analyzed for β-carotene, retinol, α-tocopherol, colorimetry profile, and milk components. Data were analyzed using mixed-effects models in SAS (SAS Institute Inc.). Calf serum β-carotene data were analyzed using the FREQ procedure. Colostrum β-carotene was higher for BC cows. Colostrum from BC cows had increased a* [measures red (positive) to green (negative)] and b* [measures yellow (positive) to blue (negative)] colorimeter values, indicating that β-carotene altered colostrum color toward red and yellow. Supplementation did not affect colostral or calf IgG concentrations. Colostrum color indices were correlated with IgG concentrations as well as concentrations of β-carotene, retinol, and α-tocopherol. Before receiving colostrum, the concentration of β-carotene in calf serum was below the detectable threshold of 0.05 μg/mL. At 24 h of age, the number of calves with detectable β-carotene concentrations increased, with more calves from BC cows (52.1%) having detectable concentrations than calves from cows in the control group (6.1%). No differences in concentrations of retinol or α-tocopherol were observed in calf serum. Supplementation of β-carotene to cows decreased activities of gamma-glutamyl transpeptidase and glutamate dehydrogenase in calf serum. In pregnant cows already receiving adequate vitamin A, supplementation of β-carotene increased concentration of β-carotene in colostrum, altered colostrum color, and increased serum β-carotene in calves at birth.     

水溶性有机试剂萃取杜氏藻中的β-胡萝卜素

使用水溶性有机溶剂建立适用于杜氏藻中β-胡萝卜素萃取的方法。以乙酸乙酯为参比,用丙酮、甲醇、乙醇和四氢呋喃4种水溶性有机溶剂,对实验室养殖的杜氏藻体在室温条件下分别进行萃取。用C18-高效液相色谱(high performance liquid chromatography,HPLC)和C30-HPLC分别测定萃取物中β-胡萝卜素含量及其几何异构体的组成。通过比较不同溶剂萃取的β-胡萝卜素含量和所消耗的溶剂体积,筛选出适合食品工业生产中使用的水溶性萃取溶剂。在进一步考虑各溶剂的食品安全性之后,确定乙醇为最适溶剂。使用乙醇作为萃取溶剂,能够从每毫克(干质量)藻体中萃取得到β-胡萝卜素0.32μg。其中,总顺式异构体的比例占20.21%(m/m)。随后,使用4种碳水化合物和1种蛋白质水解酶对藻体的细胞壁和膜进行破坏。观察原料酶解对β-胡萝卜素萃取量和溶剂消耗的影响。实验结果表明,原料酶解可导致其中β-胡萝卜素的损失,并对溶剂消耗无明显改进,不建议采用。     

Effects of α-tocopherol, β-carotene and ascorbyl palmitate on oxidative stability of butter oil triacylglycerols

Butter oil triacylglycerols (BO-TAGs), free of antioxidants, including β-carotene, were obtained via sequential treatments with activated carbon (AC) adsorption and alumina column chromatography. α-Tocopherol, β-carotene and ascorbyl palmitate (AP) were added to BO-TAGs, individually, or in different combinations. An accelerated oven-oxidation test was carried out at 60 °C to determine the most effective dosages of the antioxidants. Among the antioxidants evaluated, α-tocopherol was found to be the most effective, at the concentration of 50 μg/g. To determine the possible synergism between the antioxidants, binary or ternary combinations of α-tocopherol, β-carotene and AP were added to BO-TAGs at concentrations of 50, 5, and 50 μg/g, respectively. Ternary combinations of these antioxidants were significantly better in retarding oxidation than were binary blends of α-tocopherol with β-carotene or AP. However, a prooxidant effect was observed, especially when β-carotene and AP were used individually or in binary combination.     

Cr~(3+)对盐藻生长的影响及其在细胞中的富集和分布

本文研究了Cr3+对盐藻生长和细胞形态的影响,并对其在盐藻中的富集和在盐藻主要大分子化合物中的分布进行了探索和分析。结果表明,低浓度的Cr3+促进盐藻的生长,而高浓度的Cr3+对其生长产生抑制作用,并对盐藻细胞形态产生不良影响。CrCl3·6H2O浓度为2mg/L时,Cr3+对盐藻生长和Cr3+富集均产生促进作用,其富集量达到779.64μg/g,富集率达到85.27%。实验结果还表明,铬跟盐藻中主要大分子化合物都有结合作用,而且主要与多糖结合。