新月菱形藻的紫外诱变及优化培养

本实验室通过紫外诱变得到一株富含油脂的新月菱形藻BC6,在实验室条件下研究了不同温度、光照强度、pH值、N源含量、NaCl含量等培养条件对BC6生长的影响。研究结果表明：最适培养温度在20 ℃,pH值为7.5,最适光照强度为54 μE/(m2·s),NaNO3的最适添加量为105 mg/L,NaCl最适添加量为27 g/L。在优化培养条件下,最高细胞密度可达1.69×106 /mL,比优化前增大了2.2倍。     

两种海洋饵料硅藻的超低温保存

用两步冷冻法对牟氏角剌藻和新月菱形藻进行了超低温保存,研究了影响存活率的内外因素．结果表明,对这两种藻分别选用１０％ 和１５％ ＤＭＳＯ为抗冻保护剂,预冻至－ ４０℃并保持３０ ｍ ｉｎ 后投入液氮,样品化冻后分别在室温及０℃采用较慢的稀释速率去除ＤＭＳＯ时可获得较高的存活率．此外,处于静止期或经过低温驯化的藻细胞也表现出较大的抗冻性．通过优化内外条件,两种藻的存活率分别达到９１．５％ 和６３．１％ ．     

底栖硅藻新月筒柱藻对锌胁迫的生理学效应

采用流式细胞仪检测细胞增长与色素含量、原子火焰吸收光谱法测定金属含量以及显微镜观察细胞状态等方法研究了红树林底栖硅藻新月筒柱藻（Cylindrotheca clostetium（Ehr．）Reimann and Lewin）暴露在重金属锌96h内的细胞增长、光合色素含量和细胞形态结构等胁迫效应，以及锌在藻细胞内外动态分布的情况．结果为：（1）在Zn^2＋浓度小于10mg／L范围内，锌对新月筒柱藻的细胞增长和色素含量均无显著抑制作用．（2）1mg／L和10mg／L的Zn^2＋对藻细胞内的叶黄素和叶绿素a的产生都有促进作用．（3）在实验开始的24h内，藻细胞处在低Zn^2＋浓度（1mg／L）时，藻细胞胞内吸收的Zn^2＋大于胞外吸附的Zn^2＋．而藻细胞处在高Zn^2＋浓度（10mg／L）时，胞外吸附的Zn^2＋较胞内吸收的大，细胞内Zn^2＋的含量处在较低水平，从而促进细胞的增长和色素的合成并使细胞免受外界高浓度锌的毒害．可见，新月筒柱藻正是通过改变对锌的富集方式，以保持细胞内锌含量的相对稳定来适应不同浓度锌的胁迫．     

密封袋半连续培养新月菱形藻

利用密封袋装置代替水泥池半连续培养新月菱形藻,通过控光、控温、控气来满足新月菱形藻的生长条件要求,进行了密封袋培养新月菱形藻的生产试验,效果明显好于水泥池培养,对培养水体的监控情况也进行了分析.并根据新月菱形藻的相对生长常数K、平均日增量X和平均倍增时间G,选出其最佳生长条件:光照5000～8000lx,水温15～20℃,pH7.8～8.5,接种浓度40×104～60×104个/mL.     

Hierarchical recognition on the taxonomy of <Emphasis Type="Italic">Nitzschia closterium</Emphasis> f. minutissima

Nitzschia closterium f. minutissima, a marine eukaryotic unicellular diatom, originally classified as Bacillariophyta/Bacillariophyceae/Bacillariales/Bacillariaceae/Nitzschia, is one of the most important feed sources in mariculture. In this study, its morphological features were examined under DIC Microscopy （differential interference contrast microscope）; its pigments and fatty acids composition were analyzed by using High Performance Liquid Chromatography （HPLC） and gas chromatography （GC）; the complete Actin cDNA, part 18S rDNA, complete ITS1 and ITS2 sequences, part 28S rDNA sequences, and a putatively encoding A5 fatty acid desaturase gene were cloned respectively and further functioned in transgenic yeast. The sequence alignments were separately conducted using the related sequences from Nitzschia closterium f. minutissima, Cylindrotheca closterium （Bacillariophyta/Baci- Ilariales/Bacillariaceae/Cylindrotheca） and Phaeodactylum tricornutum （Naviculales） with ClustalX 1.83. No distinct difference was discovered between N. closterium f. minutissima and P. tricornutum in both biochemical and molecular level. Their identity was more than 99.6% among 18S rDNA, 5.8S rDNA and actin-gene sequences, and is up to 98.6% even among ITS1 and ITS2 sequences. Their △5 desaturase similarity was 99.4%. However, the lower similarity was disclosured between N. closterium f. minutissima and Cylindrotheca closterium, which shared less than 40% identity in the ITS1 and ITS2 sequences. So, N. closterium f. minutissima should not be placed in Bacillariales, Bacillariaceae, Nitzschia, but in Naviculales, Phaeodactylaceae, Phaeodactylum, and it was actually a strain of P. tricornutum.     

羟基自由基致死小新月菱形藻的生化机制

 船舶压载水中悬浮微藻的去除一直是一个难题。本文以小新月菱形藻（Nitzschia closterium minutissima）为压载水代表生物,研究了羟基自由基致死小新月菱形藻的生化机制。结果表明,当小新月菱形藻的浓度为1.2×106/mL时,致死小新月菱形藻的羟基溶液浓度范围为0.81~0.91mg/L。羟基自由基对小新月菱形藻的致死机制是对细胞蛋白质、藻糖和叶绿素等大分子的破坏,使其无法再生,从而达到压载水排放的生物量要求。     

南海珠江口伶仃洋浅层沉积硅藻的研究

在珠江口和南中国海伶仃洋的六个岩芯中,发现线纹小环藻组群(CyclotelIa striata complex)在各地层中均有分布,其数量由下层到上层呈递减的趋势。对各采集点样品进行多样性指数分析和聚类分析的结果表明,埋深为316—326cm处沉积硅藻的多样性指数最大,为2.09,111—125cm处最小,为0.36;在所有采样点中,有四对采样点相近程度大,环境条件应较为相近。     

Photodegradation of 17α-Ethynylestradiol in Aqueous Solution with Nitzschia hantzschiana or Chlorella vulgaris and Fe^3＋

0　IntroductionTherehasbeenincreasingconcernabouttheenvironmentaleffectsofoestrogensandxenoestrogens[1 ] .17α ethynylestradiol(EE2 ) (Fig .1)isasyntheticestrogenicsteroidthathastherapeuticuses (e.g .Oralcontraception) .Syntheticestrogensaregenerallymorestableinwaterthannaturalestrogensandhavegreaterpotency.Theyaredifficulttobeabsolutelyremovedfromwastewatersbyprimaryandsecondarytreatment.Thedegradationchemistryofthiscom poundhasnotbeenextensivelystudied .Therearefewpublishedarticlesstudying…