Effects of Nutritional Factors on the Growth and Heterotrophic Eicosapentaenoic Acid Production of Diatom Nitzschia laevis

The effects of several nutritional factors on the growth and eicosapentaenoic acid (EPA) production of diatom Nitzschia laevis were studied. 4 LDM (quadrupled concentration of the nutrient salt) was the optimal concentration of nutrient salt for the growth and EPA production ofN. laevis. The growth ofN. laevis was inhibited when the glucose concentration was either lower than 10gL-1 or higher than 15gL-1. Both sodium nitrate and urea were good nitrogen sources for the growth and EPA production, while ammonium chloride seriously decreased the dry cell weight (DW) and the EPA content. Silicate seriously influenced the growth of N. laevis. The maximum DW of 2.34gL-1 was obtained in the presence of 150 mgL-1 Na2SiO3·9H2O. The EPA content remained almost the same when the silicate concentration was lower than 150 mgL-1; however, higher silicate concentrations resulted in a steady de- crease of EPA content. Low medium salinity (≤29) did not seem to influence the DW of N. laevis, and high salinity resulted in a decrease of DW. The highest EPA content (4.08%) and yield (110 mgL-1) were observed at the salinity of 36 and 29, respectively.     

桑沟湾养殖栉孔扇贝食物来源研究——脂肪酸标志法

运用脂肪酸标志法分析了桑沟湾养殖栉孔扇贝(Chlamys farreri)春、夏季食物来源组成。结果表明,桑沟湾养殖栉孔扇贝饵料组成中含有硅藻类、细菌、大型绿藻类、鞭毛藻类等饵料来源,且各种饵料来源比例具有较显著的季节变化。采样期间硅藻脂肪酸标志16:1/16:0(相对质量分数比,下同)从0.91降至0.45,表明扇贝硅藻类饵料来源比例呈逐渐下降趋势;细菌脂肪酸标志18:1n-7/18:1n-9比值从0.31升至0.90,奇数碳、支链脂肪酸相对质量分数从2.15%升至3.28%,表明扇贝细菌类饵料来源比例呈逐渐上升趋势;绿藻脂肪酸标志Σ(18:2n-6 18:3n-3)质量分数从2.78%升至5.77%,表明大型绿藻来源有机质饵料比例逐渐上升。栉孔扇贝脂肪酸组成中较高比例的DHA表明扇贝摄取了富含DHA的有机质,如鞭毛藻类、微型浮游动物等。栉孔扇贝食物来源的季节变化很可能是由水体中潜在食物来源的季节变化所导致。     

掺硼金刚石膜电极降解水中全氟辛酸

采用掺硼金刚石膜电极(Boron-doped diamond,BDD)为阳极的电化学氧化法降解全氟辛酸(Perfluorooctanoic acid,PFOA);对比不同电解质体系中PFOA的脱氟效果,考察初始pH、流速、电流密度、初始浓度和电解质浓度对PFOA脱氟率的影响,估算体系能耗;以甲醇(MeOH)和叔丁醇(TBA)为淬灭剂进行自由基淬灭实验,分析PFOA的降解机理。结果表明:Na2SO4电解质体系中,PFOA具有良好的降解效果;酸性条件下(pH为3~4.2)PFOA脱氟效果较佳,中性条件下较差,脱氟效果随初始浓度的增加而降低,随电流密度的增大先提升后趋于稳定。初始pH为3、电流密度30 mA·cm^-2、流速32.5 mL·min^-1、初始浓度100 mg·L^-1、Na2SO4浓度0.05 mol·L^-1条件下,电解180 min,PFOA脱氟率达53.45%,能耗约为1.13 kWh·(g F)-1;硫酸盐体系产生的·OH、SO-4·两种自由基均能氧化降解PFOA。     

铜精矿化学成分分析实验室间比对结果评价和离群值原因分析

铜精矿成分分析是判定其品质的重要手段,尤其是主元素铜的分析.目前,测定铜精矿中铜含量的主要分析方法有碘量法、电感耦合等离子体发射光谱法(ICP-OES)、火焰原子吸收光谱法(FAAS)、X射线荧光光谱法(XRF)、电解重量法等.为确保检测标准量值统一、准确、可靠,本文组织开展了铜精矿中铜镁铅锌的测定实验室间比对活动.通...     

矿物-腐植酸-微生物体系对重金属吸附研究

设施农业中土壤重金属污染问题日趋严重.由于土壤中矿物、腐植酸、微生物等多相组分之间存在交互作用,重金属与土壤单组分体系中所获得的结合机制并不能真实有效地评价其在自然条件下的转化与归趋.本研究以蒙脱石(Mont)和高岭石(Kao)为辽宁蔬菜大棚及农田土壤层状硅酸盐代表矿物,选取胡敏酸(HA)为有机质代表,土著微生物革兰氏...     

褐藻酸降解菌感染海带过程中几种酶的作用比较

采用植物单细胞和原生质体游离的方法,研究了5株褐藻酸降解菌感染过程中海带细胞壁的组成成分——褐藻酸的变化。结果表明,海带在5株褐藻酸降解菌感染的初期(前3 d),褐藻酸酶对其单细胞和原生质体的游离率均显著降低,而且随着感染时间的延长,游离率的下降越加明显。3 d过后,随着感染的继续进行,单细胞和原生质体的游离率变化不再明显。表明海带细胞壁组成对褐藻酸降解菌感染发生了响应性变化,而这种变化仅仅发生在褐藻酸降解菌感染的早期阶段。研究结果进一步显示,褐藻酸降解菌感染过程中海带细胞壁组成的变化主要体现在褐藻酸的变化上。     

黄鳍金枪鱼酶解物免疫活性及其氨基酸分析

本文旨在研究黄鳍金枪鱼(Thunnus albacares)碎肉中4种不同蛋白酶酶解物的3k Da超滤组分对RAW264.7细胞的免疫活性。以RAW264.7细胞为实验模型, 采用噻唑蓝比色法检测细胞增殖活性, 中性红吞噬实验检测细胞吞噬能力, Griess试剂检测细胞培养上清液中NO含量, 并分析酶解物氨基酸组成和分子量分布。实验结果表明, 胰蛋白酶酶解物在12.5~200μg·mL^-1范围内无明显细胞毒性, 能增强RAW264.7细胞吞噬能力, 浓度为400μg·mL^-1时达到最大值132.50%(P<0.01), 浓度在50~200μg·mL^-1范围内能促进巨噬细胞NO释放(P<0.01), 且NO释放量与酶解液浓度存在一定的量效关系; 胰蛋白酶酶解物中必需氨基酸(essential amino acid, EAA)含量最高, 为51.09%, 其碱性氨基酸组氨酸、赖氨酸和精氨酸的含量分别为11.59%、11.00%和6.90%, 均高于其他蛋白酶酶解物, 并且分子量小于1k Da的小肽含量高达97.48%。研究结果表明, 4种蛋白酶酶解物中, 黄鳍金枪鱼碎肉胰蛋白酶酶解物的3k Da组分具有较明显的免疫活性, 这为其作为免疫活性肽的开发利用提供了理论依据。     

海洋动物营养生态位研究方法及其应用

食物资源对海洋动物的生存和繁衍至关重要。海洋动物的营养生态位描述了其在海洋生态系统中的生态地位及功能, 对分析种间关系和资源分配模式、了解群落结构与功能具有重要的指示作用。本文在整理近30年来国内外相关研究的基础上, 系统归纳了当前海洋动物营养生态位研究的主要方法(胃含物分析、整体组织稳定同位素分析、脂肪酸组成分析和特定化合物稳定同位素分析)及其应用领域, 着重归纳总结了量化营养生态位宽度和重叠的生态模型, 并分析了各营养生态位评估方法的优势和局限性。同时在此基础上, 对今后研究方向提出了展望, 以期为我国海洋动物摄食生态学相关研究工作提供参考。     

Fecundity of the snapper Chrysophrys auratus (Pisces: Sparidae) from the Hauraki Gulf

Fecundity estimates were made for snapper Chrysophrys auratus, a serial spawning fish, for the 1974–75 and 1975–76 spawning seasons. Weighed sub‐samples of ovaries were used, and eggs were counted manually. All eggs >0.1 mm diameter were considered potentially capable of being spawned; estimates of these eggs were made at the beginning and end of spawning, and their difference was considered to be the actual fecundity. A log‐log transformation of egg numbers against length offish gave a linear relationship. Fecundity estimates ranged from 297 000 at 25 cm to 4 528 000 at 50 cm in 1974–75, and from 83 000 at 25 cm to 6 164 000 at 50 cm in 1975–76. Counts of ripe eggs were also made, and batch sizes ranging from 13 000 at 25 cm to 104 000 at 50 cm were predicted. By combining these data with fecundity estimates the number of batches spawned was estimated to be 23–44 in 1974–75, depending on and increasing with length; and 6–59 in 1975–76.