Biomass and nutrient productivities ofTetraselmis chuii under mixotrophic culture conditions with various C：N ratios

Mass microalgal culture plays an irreplaceable role in aquaculture,but microalgal productivity is restricted by traditional autotrophic culture conditions.In the present study,a Tetraselmis chuii strain belonging to the phylum Chlorophyta was isolated from south Yellow Sea.The growth rate and biomass productivity of this strain was higher under mixotrophic conditions with different carbon:nitrogen(C:N)ratios than those under autotrophic conditions.When the C:N ratio was 16,the optical density and biomass productivity were 3.7-and 5-fold higher than their corresponding values under autotrophic culture conditions,respectively.Moreover,T.chuii synthesized more polysaccharides and total lipids under mixotrophic conditions.In addition,T.chuii cultured under mixotrophic conditions synthesized more types of fatty acids than autotrophic culture conditions.At a C:N ratio of 16,the percentage of C16:0 and C18:1 reached 30.08%and 24.65%of the total fatty acid(TFA) content,respectively.These findings may provide a basis for largescale mixotrophic culture of T.chuii,as a potential bait-microalga.

Growth, Proximate Composition and Pigment Production of Tetraselmis chuii Cultured with Aquaculture Wastewater

Microalgae are cultured commercially as healthy food, cosmetic products, food preservatives, and a source of valuable compounds. However, the high cost of commercial culture medium is one of the challenges to microalgal production. Therefore, it is essential to find an alternative cost-effective culture medium. Aquaculture wastewater is considered as a highly potential candidate due to its high nutrient content and large quantity generated from the rapid growth of aquaculture sector. In this study, Tetraselmis chuii cultured in different media with or without wastewater was evaluated for its growth, proximate composition and carotenoid production. The results showed that significantly(P < 0.05) higher growth(4.3 × 105 cells mL^(-1)) and protein(56.4% dry weight), lipid(44% dry weight) and carbohydrate(20% of dry weight) contents were found in T. chuii when they were cultured in the combination of both wastewater and Conway(wastewater + Conway) medium. However, carotenoid production of T. chuii was significantly increased(P < 0.05) when it was cultured in wastewater only, followed by Conway + wastewater and Conway medium only. Therefore, the incorporation of wastewater with commercial medium Convey is recommended for a cost-effective microalgae culture, as well as for the enhancement of growth and nutritional content of microalgae.

Precise identification of photosynthetic glycerolipids in microalga Tetraselmis chuii by UPLC-ESI-Q-TOF-MS

Precise structural identification of photosynthetic polar glycerolipids in microalga Tetraselmis chuii has been established using Ultra Performance Liquid Chromatography–Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry (UPLC-ESI-Q-TOF-MS) by direct analysis of the total lipids extract. The mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in both positive and negative modes. The structural determination was based on the char-acteristic product ions yielded by different glycerolipids under ESI-MS/MS mode, and confirmed the molecular species by the carboxylate anions produced by glycerolipids in the negative mode. As a result, more than 40 lipid molecular species, including 11 monogalactosyldiacylglycerols (MGDG), 7 digalactosyldiacylglycerols (DGDG), 16 sulfoquinovosyldiacylglycerols (SQDG), and 9 phosphatidyl-glycerols (PG), were detected in Tetraselmis chuii, which had never been identified before in this mi-croalga. Furthermore, some intact lipid molecules with hydroxylated fatty acids that could not be de-tected by the traditional GC-MS method were found this time, providing novel information for the pho-tosynthetic lipidome of Tetraselmis chuii. Comparative studies on fatty acids at the sn-2 position showed that SQDG and MGDG are dominantly biosynthesized through the prokaryotic pathway, PG is a typically mixed biosynthetic pathway, while DGDG is somewhat peculiar with C14:0 and C16:0 at its sn-2 position. This method could provide a full structural profile of intact photosynthetic lipid molecular species, which may be applied to study the physiological and ecological functions of lipid by monitor-ing their individual changes.

对虾育苗中常用海洋微藻抑菌作用的研究

研究了等鞭金藻、三角褐指藻、扁藻对对虾育苗中致病菌鳗弧菌、假单胞菌的抑菌效果。结果表明,等鞭金藻、三角褐指藻、扁藻的水溶性物质及脂溶性物质对鳗弧菌有抑制作用;等鞭金藻、三角褐指藻的水溶性物质及等鞭金藻、三角褐指藻、扁藻的脂溶性物质对假单胞菌有抑制作用。在抑菌试验中,等鞭金藻、三角褐指藻、扁藻密度达10×104/ml时,对对虾育苗池水的抑菌作用较好,特别是对弧菌的抑制效果明显。

臭氧处理海水生成氧化物对扁藻生长的影响

研究了臭氧处理海水生成氧化物对扁藻 (Tetraselmis chuii)生长的影响。臭氧生成氧化物浓度在 0 .736 mg/ L以下不产生毒害作用 ,在 1.113mg/ L以上观察到了毒害作用 ,并且浓度越高毒性越强。实验发现扁藻对臭氧生成氧化物的毒害有抵抗能力。

鸭公树子中生物碱类成分及抗炎镇痛活性研究

目的:研究鸭公树子中生物碱类化学成分及抗炎镇痛活性。方法:采用SephadexLH-20柱色谱法、薄层色谱法及高效液相制备色谱法等,对鸭公树子中的化学成分进行分离;通过核磁共振氢谱(1H-NMR)、核磁共振碳谱(13C-NMR)、质谱法(MS)等鉴定化合物结构;采用二甲苯致小鼠耳廓肿胀实验和小鼠扭体实验分别观察单体成分的抗炎、镇痛作用效果。结果:从鸭公树子三氯甲烷提取部位中分离得到9个生物碱类化合物,分别鉴定为樟苍碱(1)、N-甲基樟苍碱(2)、乌药碱(3)、波尔定碱(4)、新木姜子碱(5)、杏黄罂粟碱(6)、异紫堇定碱(7)、烟酰胺(8)、N-反式阿魏酰酪胺(9)。新木姜子碱能抑制二甲苯所致的小鼠耳肿胀(P<0.01),并能减少醋酸所致的小鼠扭体次数(P<0.01)。结论:所有化合物均为首次从鸭公树子中分离得到,新木姜子碱显示出明显的抗炎镇痛活性,可能是该植物的活性成分之一。

中药鸭公树子化学成分研究

目的:研究中药鸭公树子的化学成分。方法:用硅胶、聚酰胺柱层析和重结晶等方法对鸭公树子化学成分进行分离,并根据化合物的理化性质及UV、IR、1H-NMR、13 C-NMR、HR-MS等方法分析、鉴定化合物结构。结果:从鸭公树子乙酸乙酯提取部位中分离和鉴定出7个化合物,分别是球松素(1)、银松素(2)、槲皮素(3)、山柰酚(4)、β-谷甾醇(5)、苯甲酸(6)、对羟基苯甲醛(7)。结论:化合物1~7均为首次从鸭公树子药材中分离得到,该研究可为鸭公树子药材的进一步开发利用奠定基础。

鸭公树子化学成分研究(Ⅱ)

目的:进一步研究中药鸭公树子的化学成分。方法:用硅胶、聚酰胺柱层析和重结晶等方法对鸭公树子化学成分进行分离,并根据化合物的理化性质及1H-NMR、13 C-NMR、HR-MS等方法分析、鉴定化合物结构。结果:从鸭公树子提取物中分离和鉴定出8个化合物,分别是薯蓣皂苷(Ⅰ)、薯蓣次苷B(Ⅱ)、腺苷(Ⅲ)、3-羟基-2,4,7-三甲氧基-9,10-二氢菲(Ⅳ)、吐叶醇(Ⅴ)、木犀草素(Ⅵ)、(S)5-乙基-8,8-二甲基壬醛(Ⅶ)、对羟基苯乙酸乙酯(Ⅷ)。结论:化合物Ⅰ~Ⅶ均为首次从鸭公树子中分离得到。

鸭公树子化学成分预试验研究

目的:采用系统预试法对鸭公树子可能含有的化学成分进行分析研究,初步探索鸭公树子中所含的化学成分。方法:采用经典的化学反应鉴别法,以鸭公树子的水提取液、乙醇提取液和石油醚提取液进行研究,结合多种指示剂和显色剂,观察反应结是否沉淀或者颜色反应。结果:鸭公树子中含有多肽类、蛋白质类、多糖类、生物碱类、黄酮类、甾体类、皂苷类、内酯类、三萜类、有机酸、挥发油及油脂类等成分。结论:初步确定鸭公树子含有的多种化学成分,为鸭公树子药材资源的进一步开发和利用提供基础。