硒(Ⅳ)对微藻生长的影响及NO对硒胁迫调控作用的初步研究

以小新月菱形藻和赤潮异弯藻为培养对象,研究不同浓度外源硒(Ⅳ)对微藻生长的影响,并初步研究了一氧化氮(NO)和高浓度硒对微藻生长的联合影响.结果表明:硒(Ⅳ)高浓度(10-4～10-5)时起抑制作用;低浓度时(10-7～10-9 mol/L)起促进作用,这与一般的微量元素的作用规律相似.每天2次加入1.4×10-9 mol/L NO能缓解一次性加入高浓度(10-5 mol/L)硒对微藻的毒性作用,这可能与NO能调控细胞内抗氧化系统有关.     

Strain H<Subscript>2</Subscript>-419-4 of <Emphasis Type="Italic">Haematococcus pluvialis</Emphasis> induced by ethyl methanesulphonate and ultraviolet radiation

Two strains H2-410 and H2-419 were obtained from the chemically mutated survivors of wild Haematococcus pluvialis 2 by using ethyl methanesulphonate (EMS). Strains H2-410 and H2-419 showed a fast cell growth with 13% and 20% increase in biomass compared to wild type, respectively. Then H2-419-4, a fast cell growth and high astaxanthin accumulation strain, was obtained by exposing the strain H2-419 to ultraviolet radiation (UV) further. The total biomass, the astaxanthin content per cell, astaxanthin production of H2-419-4 showed 68%, 28%, and 120% increase compared to wild H. pluvialis 2, respectively. HPLC (High Performance Liquid Chromatography) data showed also an obvious proportional variation of different carotenoid compositions in the extracts of H2-419-4 and the wild type, although no peak of carotenoids appeared or disappeared. Therefore, the main compositions in strain H2-419-4, like its wild one, were free of astaxanthin, monoester, and diester of astaxanthin. The asexual reproduction in survivors after exposed to UV was not synchronous, and different from the normal synchronous asexual reproduction as the mother cells were motile instead of non-motile. Interestingly, some survivors from UV irradiation produced many mini-spores (or gamete?), the spores moved away from the mother cell gradually 4 or 5 days later. This is quite similar to sexual reproduction described by Elliot in 1934. However, whether this was sexual reproduction remains questionable, as no mating process has been observed.     

Optimization of culturing condition and medium composition for the production of alginate lyase by a marine <Emphasis Type="Italic">Vibrio</Emphasis> sp. YKW-34

Carbohydrases secreted by marine Vibrio sp. YKW-34 with strong Laminaria cell wall degrading ability were screened, and among them alginate lyase was found to be dominant. The effects of medium composition and culturing condition on the production of alginate lyase by marine Vibrio sp. YKW-34 in flask were investigated in this study. In the culture medium of marine broth, no alginate lyase was produced. The activity of the alginate lyase, after being induced, reached 5 UmL^-1. The best inoculum volume and inoculum age were 10% and 12h, respectively. The optimal temperature for alginate lyase production was 25℃. The fermentation medium was composed of 0.5% of Laminaria powder and 0.2% of KNO3 with an initial acidity of pH 8.0. Alginate could induce alginate lyase production but not as efficiently as Laminaria powder did. The addition of fucoidan, cellulose and glucose had negative effect on the alginate lyase production. Other kinds of nitrogen sources, such as yeast extract, beef extract and peptone, had positive effect on the growth of the microorganism and negative effect on alginate lyase production. In addition, the time course of alginate lyase production under the optimized condition was described. The optimal harvest time was 48 h.     

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.     

漂浮型铜藻与养殖裙带菜的光合作用、生长和物质积累的差异及其在两种藻竞争中的作用

近年来,由漂浮型铜藻(Sargassum horneri)频繁引发的金潮对东海、黄海沿岸的经济海藻养殖造成了巨大威胁.本研究针对3个生长阶段的裙带菜(Undaria pinnatifida)和同期出现的铜藻,测定二者在不同温度和不同光照强度下的光合速率;本研究设计了温度、光照和培养模式这3个因素:温度1月为5℃,4月为...     

圆台型混凝土人工藻礁礁体结构设计及其稳定性分析

针对我国南海北部湾东部投放藻礁海域的海况条件,设计圆台型人工藻礁,以实现该海域马尾藻的人工增殖与移植。基于波流动力学理论,计算圆台型人工藻礁礁体不同海流速度下的作用力、抗滑移系数及抗翻滚系数,探讨礁体的稳定性。结果表明:在波、流共同作用下,礁体最大受力为171.8 N,最大作用力矩为49.64 N·m,抗漂移系数S1范围为2.88~25.09,抗倾覆系数R1范围为2.06~315.00,满足礁体稳定条件,礁体在该海域正常情况下不会发生漂移或倾覆现象。     

小球藻、盐藻光学特性的初步试验研究

利用分光光度计和赤潮生物快速检测仪对盐藻、小球藻的光谱特性、显微图像和荧光图像作了对比研究。结果表明:盐藻和小球藻都在400~450 nm之间(对应胡罗卜素)和650~700 nm之间(对应叶绿素)有吸收峰,但盐藻在近红外波段(960 nm附近)还有一峰值。泥沙的吸光值随波长增加单调递减。盐藻的荧光图像呈现红色,当有泥沙存在时,盐藻的荧光会被泥沙散射,该现象对于通过荧光图从泥沙中分辨藻是不利的。     

凹顶藻属海藻化学成分研究进展

海洋生物通过生物链、化学信息传送、化学进攻、化学防御等机制相互依存、相对独立、维系着独特紧密的海洋生物体系,作为海洋物质代谢原动力的海藻为了对抗食藻动物的吞食,大多能产生一些有特色的代谢物质,其中凹顶藻属因富含萜类化合物著称,这类化合物含有异戊二烯结构单元,不     

免疫学方法在有害赤潮藻细胞检测中的应用

赤潮可以严重危害海洋渔业、海水养殖业和旅游业,甚至危害到人类的生命健康[1,2],它的频繁发生已经引起各国政府的高度重视。虽然可以通过每日多次实时检测海水的水文、化学要素等来推测发生赤潮的可能性[3],但是这些方法都不能直接反映有害赤潮藻的种类和数量,从而不能为赤潮监测和预报提供最直接的参考数据。实际上,对海水中的藻类进行分类、鉴定和数量分析是监测和预报赤潮发生的最直接有效的方法,这包括对水样采集、藻种类鉴定、毒性鉴定和赤潮藻定量计数等。传统的形态分类技术可以解决赤潮监测中的多数问题,但需要有经过专门训练的分…     

8种抗生素对塔玛亚历山大藻生长的影响

对一株有毒的塔玛亚历山大藻(Alexandrium tamarense(Lebour) Balech)进行了8种抗生素-氯霉素、红霉素、林可霉素、庆大霉素、金霉素、氨苄青霉素、新霉素和链霉素的敏感性实验.结果表明,该藻对抗生素较为敏感.其中的5种:氯霉素、红霉素、林可霉素、庆大霉素和金霉素,对藻8d比生长速率的EC₅₀分别为2.45μg/cm3,25.2μg/cm3,7.95μg/cm3,285u/cm3,58.7μg/cm3,可用作该藻基因工程的选择压力,其对应的抗性基因可以作为基因工程阳性选择标记基因,应用于塔玛亚历山大藻的遗传操作研究.新霉素和链霉素对A.tamarense的生长无明显抑制作用,可以用于藻株无菌化培养而应用于甲藻产毒机制和赤潮爆发机理的研究,还应用筛选出的抗生素对藻培养物进行了除菌实验.