一个新的来自于弧菌QD-5并具有Poly-G内切功能的褐藻胶裂解酶的克隆和性质表征

Seven bacterial clones with alginate-utilizing activity were isolated from rotten kelp. By activity test, the Vibrio sp.QD-5 with the potential alginate-degrading capability was chosen to carry out the draft genome sequencing, and the result showed that the Vibrio sp. QD-5 containing an alginate lyase gene cluster. One of these genes, aly-IV,was cloned and characterized for the first time. After overexpression, Aly-IV, with a molecular mass of about62 kDa and a theoretical isoelectric point(pI) of 5.12, was purified to a specific activity of 1 256.78 U/mg and showed highest activity at 35°C in the Tris-HCl buffer at pH of 8.9. Moreover, the enzyme activity was enhanced by the metal ions of Na~+, K~+ and Mg~(2+) under certain concentration. Aly-IV degraded favorably polyG blocks in an endo-type, yielding monomer and dimer as the main products. Due to its high substrate specificity, Aly-IV could be used as a potential tool for production of polyG oligosaccharides with low degree of polymerization(DP) and for determining the fine structure of alginate.     

重金属锌对海洋微藻藻源氨基酸产出的影响

锌是海洋微藻生长必需的金属元素,低浓度时可促进微藻的生长,而在高浓度时则表现为抑制其生长。受人类活动的影响,海洋中锌有富集增加的趋势,从而会对海洋微藻的生长产生影响。本论文探究了锌离子以及纳米氧化锌对硅藻中肋骨条藻(Skeletonemacostatum)和新月菱形藻(Nitzschia closterium)生长的影响,特别是对藻源氨基酸产生的影响,结果发现:纳米金属颗粒会通过释放离子的形式抑制海洋浮游植物的生长,中肋骨条藻比新月菱形藻对锌的响应更敏感。锌离子和纳米氧化锌可通过抑制浮游植物的生长来减少氨基酸的释放量和改变藻源氨基酸的种类,从而可能会对海洋氮循环过程产生影响。     

矿物培养影响微生物群落的ERIC研究

从江西东乡铜矿、江西银山铅锌矿和广东云浮硫铁矿三地采集了酸性矿坑水样品,用ERIC方法(肠细菌重复内源同源序列方法)分析了经不同矿物培养后的微生物变化情况。结果发现:不同矿山酸性矿坑水样品的化学性质及其微生物组成存在很大差异,同一样品经不同矿粉培养后微生物群落也会发生比较大的变化;样品经组成相似的能源物质培养后,其微生物群落结构也越相似。确定了ERIC方法用于酸性矿坑水样品时的最佳扩增体系和反应程序。     

鱿鱼营养成分分析

对黑鱿与阿根廷鱿的营养成分作了分析,并评价了它们的营养价值。研究表明：两种鱿所含营养成分大致接近。鱿的蛋白质含量高达７３．３％～７８．８％,而脂肪含量小于４．２０％,这有利于鱿鱼干制品的加工与贮存。两种鱿的氨基酸含量比较丰富,其中谷氨酸、天冬氨酸含量特别高。阿根廷鱿氨基酸含量更为丰富,其亮氨酸稍高于鸡蛋白     

3种海洋养殖贝类体内的脂肪酸组成

分析了华贵栉孔扇贝Ｃｈｌａｍｙｓｎｏｂｉｌｉｓ（Ｒｅｅｖｅ）、合浦珠母贝Ｐｉｎｃｔａｄａｍａｔｅｎｓｉｉ（Ｄｕｕｋｅｒ）、翡翠贻贝Ｐｅｒｎａｖｉｒｌｄｉｓ（Ｌｉｎｎａｅｕｓ）的软体部、肝胰腺和生殖腺的脂肪酸组成及含量。３种贝的各组织中,不饱和脂肪酸含量均较饱和脂肪酸含量高。多不饱和脂肪酸（ＰＵＦＡ）含量丰富,其中二十碳五烯酸（ＥＰＡ）和二十二碳六烯酸（ＤＨＡ）含量相当高,占总脂肪的２５．２６％－２７．２１％。３种贝中,翡翠贻贝的油含量最高（１３．６８％）,软体部的ＥＰＡ和ＤＨＡ含量也较高（２６．９５％）,最具开发利用价值。     

中国对虾(Penaeus chinensis)的白点综合征病毒(WSSV)的提纯和核酸提取

作者从发生白点综合征的中国对虾中,提取了一株白点综合征病毒,用电镜对纯化的病毒进行了形态学观察,并对病毒纯化过程中蛋白酶抑制剂的使用及离心速度的选择进行了探讨。经蔗糖密度梯度离心,分取各带负染后电镜观察,病毒条带位于４０％～５０％蔗糖梯度之间,其完整毒粒长２２５～２７０ｎｍ,直径７５～８８ｎｍ,有的完整毒粒带有很长的尾,病毒衣壳长２５０～３２０ｎｍ,直径６０～８０ｎｍ。在匀浆使用的缓冲液中加入蛋白酶抑制剂ＰＭＳＦ,可得到完整的带包膜的病毒颗粒,比不使用ＰＭＳＦ的提纯效果要好。经３０００ｒ／ｍｉｎ离心５ｍｉｎ,５０００ｒ／ｍｉｎ离心２５ｍｉｎ,去除大部分的组织碎片,经１００００ｒ／ｍｉｎ离心１ｈ,可使大部分病毒沉淀。并采用传统的方法对病毒核酸进行了提取,其基因组经初步分析为ｄｓＤＮＡ。     

Dynamics of fatty acids in newly biosynthesized phytoplankton cells and seston during a spring bloom off the west coast of Hokkaido Island, Japan

¹³C uptake experiments were carried out at a station off the west coast of Hokkaido Island, Japan, during the period between late winter and spring bloom in 1997. The composition of newly biosynthesized particulate fatty acids was determined using a ¹³C tracer and gas chromatography/mass spectrometry (¹³C GC/MS), and compared with that of particulate matter (seston). Two fatty acid compositional ratios revealed that diatoms biomass (16:1(n−7)/16:0, ∑C₁₆/∑C₁₈) were strikingly high in new cells compared with seston on 17 April, coinciding with the dominance of fucoxanthin. In this study, the Polyunsaturation Index (a measure of the percentage of C₁₆ fatty acids that are polyunsaturated) in new cells is generally close to that in seston, while there was a notable discrepancy between new cells and seston in surface (10 m) waters on 17 April. This large difference between new cells and seston is ascribed to: (1) an increase of newly synthesized storage lipids (mainly 16:0 and 16:1) induced by nitrogen limitation in the top 10 m of the water column; (2) an addition of earlier synthesized phytoplankton cells (high Polyunsaturation Index at logarithmic growth stage) and non-phytoplankton components (detritus and bacteria and zooplankton) into seston. The highest Polyunsaturation Index of C₁₆ fatty acids in seston (33%) occurred at 100 m water depth. This may be caused by “settling planktonic aggregates” or “diatom resting spores”. In the present study, it is reasonable to suggest that the Polyunsaturation Index of C₁₆ fatty acids can be a useful indicator for the ecophysiological state of marine diatom populations.     

氮源和N/P对眼点拟微球藻的生长、总脂含量和脂肪酸组成的影响

报道了ＮａＮＯ３,ＮＨ４Ｃｌ和ＮＨ４ＮＯ３种氮源及Ｎ／Ｐ对海洋微藻眼点拟微球藻（Ｎａｎｎｏｃｈｌｏｒｏｐｓｉｓ ｏｃｕｌａｔａ）的生长、总脂含量和脂肪酸组成的影响。结果表明,Ｎ／Ｐ从１０增加到９０,对细胸生长的影响不大,总脂含量最终都稳定在干重的２０％左右。１６：０、１６：Ｉｎ－９和２０：５ｎ－３（ＥＰＡ）是脂肪酸的主要组成,三者之和占总脂肪酸的７０％～８０％。在培养基Ｎ／Ｐ〉２０时,２０：５０ｎ     

几种化合物改变纤维海泡石对红细胞毒性初探

纤维海泡石对红细胞有毒性。本文采用阳离子交换、Ｇａｍｂｌｅ溶液、有机酸及尼古丁处理纤维海泡石,观察处理前后红细胞的溶血率及指质过氧化的主要产物丙二醛（ＭＤＡ）的变化。结果显示：经过阳离子交换及Ｇａｍｂｌｅ溶液处理,纤维海泡石对红细胞的毒性显著降低,其机制可能是延长了界／膜形成时间,降低了脂质过氧化的强度;有毒物质,如尼古丁的参与则增强了海泡石对红细胞的毒性;有机酸处理对红细胞的毒性影响不明显。     

养殖大黄鱼生化组份的分析

本文测定了厦门火烧屿养殖大黄鱼成、幼鱼肌肉中蛋白质、脂类和糖类等生化组份,并计算其比能值;分析了肌肉蛋白南中１７种常见氨基酸的含量。结果表明：成鱼肌肉蛋白质占１８．９％（湿重比,下同）脂类为３．１１％,糖类为１．６２％,水份占７５．３０％,灰份为０．９５％。比能值为５．９７ＫＪ／ｇ,Ｅ／Ｐ值为３１．６２ＫＪ／ｇ。幼鱼肌肉中占７５．３０％,灰份为０．９５％。比值为５．９８ＫＪ／ｇ,Ｅ／Ｐ值为３１．６