用于单一藻细胞PCR扩增反应的样品保存方法比较

用室内培养的塔玛亚历山大藻(Alexandrium tamarense ATHK藻株)作为实验对象,分别选择了5%福尔马林固定后常温保存、95%乙醇固定后常温保存、-20℃冷冻保存、鲁哥氏液(Lugols solution)固定后常温保存等方法,在5,15,30,60 d后对保存的样品进行单细胞PCR反应,并与新鲜样品进行比较。实验结果表明,用95%乙醇保存、-20℃冷冻保存、鲁哥氏液保存的样品在60 d后仍可扩增出目标条带,与新鲜样品没有差别,但是样品中的藻细胞形态有一些改变;而以5%福尔马林固定保存的样品只能在5 d后扩增出目标条带,但藻细胞形态比较完好。因此,对用于单细胞PCR实验的微藻样品,短期内(不多于5 d)可以采用福尔马林保存,而需要长期保存的样品,应当采用乙醇或鲁哥氏液固定,或者采用-20℃冷冻保存的方法。     

亚铁离子对赤潮异弯藻种群消长和部分生化特性的影响

研究了赤潮异弯藻(Heterosigma akashiwo)在不同浓度的Fe(NH4)2(SO4)2.6H2O(Fe1)和FeSO4.7H2O(Fe2)(浓度分别为:高铁150 nmol/L、低铁50 nmol/L,缺铁0 nmol/L Fe0)中的种群消长过程、单位细胞总多糖特征、光合色素chla、chlc变化以及NO3--N的吸收情况。结果表明,Fe2 浓度影响到赤潮异弯藻的消亡:缺铁组比高铁组种群消亡慢。在平台期和衰亡期时,Fe1各组单位细胞总多糖含量均明显高于Fe2各组。从平台期到衰亡期,各组单位细胞多糖含量明显增加,Fe2各组增量最大,Fe1各组多糖倍增与Fe0相似。亚铁离子浓度的进一步增加有利于单位细胞色素chla和chlc的积累。亚铁离子的不同化合物状态影响到多糖和光合色素的累积,但不影响种群生长率和对NO3--N的吸收。     

几种海洋溶藻菌溶藻效果研究

选择海南三亚红沙港易发赤潮--塔马亚历山大藻(Alexandriumtamarense)和中肋骨条藻(Skeletonemacostatum)做为实验藻类,从三亚红沙港海域筛选的海洋细菌中分离出一株溶藻细菌,编号为B7和已发现具有抑藻作用的:恶臭假单胞菌、铜绿假单胞菌、巨大芽孢杆菌作为实验材料与两种藻共同培养表现的牛态关系的差异性.结果表明:在实验室条件下,分别在藻细胞生长的延滞期和指数期加入细菌过滤液,发现4种海洋细菌的过滤液对两种藻生长有不同的抑制作用效果.同时文中对海洋细菌抑藻作用机理、赤潮的生物防治可能性进行了讨论.     

胞外滤液对球等鞭金藻生长速率和胞内生化成分含量的影响

以4个不同生长阶段的球等鞭金藻的胞外滤液为研究对象,研究其对球等鞭金藻藻生长速率和胞内生化成分含量的影响。结果表明,随着胞外滤液老化程度的逐渐增加,藻细胞的生长速率及胞内物质的含量受到越来越强烈的影响,表现为生长速率呈现负值,胞内生化成分的含量降低。即便是补充了足够的营养盐,也无法消除胞外滤液的抑制作用。实验证明,球等鞭金藻在生长过程中产生的抑制物在影响其生长的同时,对胞内物质也有一定的抑制作用。     

光学活性藻蓝蛋白β亚基的体内重组

在Synechococcus sp.PCC 7002中,首先发现了特异性催化脱辅基藻蓝蛋白β亚基(153位)与藻蓝胆素(phycocyanobiling, PCB)连接的裂合酶基因cpcT.本实验在Synechocystis sp.PCC 6803中找到与cpcT具有高度同源性的基因slr1649.构建2组相容的重组质粒pCDF-cpcB(C82I)或(C153I)-ho1-pcyA和pRSF-slr1649,cpcB(C82I)和cpcB(C153I)分别编码82和153位被突变的脱辅基藻蓝蛋白β亚基,slr1649编码可能的特异性裂合酶,在大肠杆菌体内生成PCB必需的2个基因(ho1编码血红素氧化酶,pcyA编码藻蓝胆素合成酶),将这些基因共同转化到大肠杆菌诱导表达,利用亲和层析柱对可溶性蛋白进行纯化,产物进行SDS-PAGE、色素蛋白锌电泳和光谱检测.结果表明基因slr1649能够特异性催化CpcB(153位)与PCB的连接,产生了具有光学活性的CpcB(C82I)-PCB,为进一步研究螺旋藻藻蓝蛋白的生物活性奠定了基础.     

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.     

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。