一株分离微拟球藻LAMB0002的鉴定

微藻的分类鉴定是进一步应用的前提。微拟球藻属的6个种都是单细胞微藻,形态简单,难以用形态学方法进行准确鉴定。本研究分离了一株微拟球藻,结合光学显微镜和透射显微镜观察、脂肪酸和色素组成分析、18SrRNA基因和rbcL基因序列分析,将该藻株鉴定为Nannochloropsis oceanica LAMB0002。本研究进行了微藻分类系统的初步探索,为今后形成系统的微藻分类体系奠定了基础。     

利用除草剂Sandoz 9785筛选高EPA微拟球藻的研究

为研究使用除草剂Sandoz 9785筛选高EPA微拟球藻的有效性,用添加不同浓度除草剂Sandoz 9785的f/2固体培养基对海洋微拟球藻(Nannochloropsis oceanica)进行处理。当除草剂浓度为58μmol/L时,可抑制99.1%的藻细胞生长,在该除草剂浓度下,筛选获得2株抗除草剂藻株SA1和SA2。将抗性藻株在无除草剂f/2液体培养基中培养到指数期和平台期,分别测定其叶绿素荧光参数。研究显示,PSⅡ的最大光能转化效率(F_v/F_m)、PSⅡ的潜在活性(F_v/F_0)、PSⅡ的实际光能转化效率(ΦPSⅡ)、PSⅡ光合电子传递效率(ETR)等均高于出发藻株。其中,SA2的比生长速率达到0.199d~(-1),较出发藻株提高了2.31%;SA1的EPA含量较出发藻株藻提高了5.44%,占总脂肪酸含量的27.35%。研究结果表明,使用除草剂Sandoz 9785可有效筛选出EPA含量较高的微拟球藻藻株。     

不同适温海洋富油微藻在富碳培养条件下的油脂积累特性研究

本实验分别针对3株低温藻株:微拟球藻Nannochloropsis sp.ZL-12、四爿藻Tetraselmis chui ZL-33和小球藻Chlorellasp.ZL-45,3株中温藻株:球等鞭金藻Isochrysis galbana CCMM5001、等鞭金藻Isochrysis sp.CCMM5002和微拟球藻Nannochloropsis sp.CCMM7001,3株高温藻株:微拟球藻Nannochloropsis sp.JN1、绿色巴夫藻Pavlova viridis JN2和海洋小球藻Chlorellasp.JN3,研究了在通入0.03%(空气)、5%、10%3个CO2浓度梯度条件下的生长特性,同时考察了其总酯及中性脂的累积情况。结果显示,富碳培养有利于不同温度条件下9株藻株的生长,除微拟球藻Nannochloropsis sp.CCMM7001最适生长的CO2浓度为5%外,其余8株藻株最适生长的CO2浓度均为10%。在低温和高温条件下,6株海洋富油微藻在通入10%CO2时具有最大生物量产率,在中温条件下球等鞭金藻和等鞭金藻在通入10%CO2时获得最大生物量产率,而微拟球藻在通入5%时获得最大生物量产率,随着CO2浓度的增加,9株藻株的总脂含量和中性脂含量有明显提高。低温和中温藻株的总脂含量高于高温藻株的总脂含量,从中性脂的累积规律来看,9株藻株均在平台期的累积达到最大值,GC-MS分析结果表明,9株微藻适合制备生物柴油的C14~C18系脂肪酸相对含量在不同CO2条件下基本保持不变,维持在90%左右。实验结果显示,所研究的藻株作为富油高固碳优良藻株,具备用于海洋生物质能耦合CO2减排开发的潜力。     

胸腺素α1间接ELISA测定方法的建立及其在转基因蓝藻中的应用

利用胸腺素α1（Tα1）－小牛血清白蛋白融合蛋白免疫新西兰兔获得的抗体，建立了Tα1间接酶联免疫吸附滴定法（ELISA），以定量检测转Tα1基因聚球藻7942外源基因表达产物胸腺素α1，实验结果表明该方法灵敏度高，专一性强，重复性好，可用于转基因微藻Tα1表达量的定量检测，同时表明Tα1基因能在聚球藻7942中稳定表达。     

微拟球藻的水产饵料效果研究

通过人工高密度培养微拟球藻(Nannochloropsis salina),对比研究了该藻作为直接饵料在栉孔扇贝(Chlamys farreri)育苗和间接饵料在牙鲆(Paralichthys olivaceus)育苗中的应用效果。结果表明,微拟球藻生长迅速、细胞颗粒小、富含EPA等不饱和脂肪酸、营养比较全面,同时具有较厚细胞壁的特点。通过不同的光生物反应器和高密度培养技术,可以比较容易地实现微拟球藻的高密度培养,藻液细胞密度维持在5~15亿个/mL的高密度水平,最高达到36亿/mL。藻体叶绿素和类胡萝卜素含量因培养条件不同而有差异,其中每个细胞内的叶绿素含量在8.60×10-13g±0.65×10-13g,类胡萝卜素含量在1.45×10-13g±0.12×10-13g。作为直接或间接饵料,微拟球藻在不同水产动物培育中的应用效果差异性很大。其中,微拟球藻作为饵料直接投喂栉孔扇贝幼虫,虽可被摄食但不容易消化,造成食物在栉孔扇贝幼苗胃内滞留盈胀,最后出现代谢性饥饿和营养不良现象进一步影响个体生长,该藻在栉孔扇贝幼虫培育中的饵料效果不很理想。相反,利用微拟球藻培育轮虫(Rotifer),然后再将后者投喂牙鲆仔鱼,作为间接饵料微拟球藻不仅大幅提高牙鲆的成活率,同时还明显增加牙鲆的生长速度,是培育仔稚鱼开口饵料轮虫的优质微藻。微拟球藻在不同水产动物育苗中应用效果明显差异的原因,主要在于该藻是否能够被充分消化吸收。因此,有效破碎微拟球藻细胞壁技术和提高消化吸收措施都将推动该藻在水产中的应用。     

培养基限氮和添加钨酸钠对微拟球藻脂肪酸组成的影响

微藻的脂肪酸组成与环境条件密切相关.选取微拟球藻(Nannochloropsis oculata)为对象,比较研究了对培养基限氮和添加钨酸钠时,其脂肪酸组成的变化.结果表明:培养基限氮时,16∶0、16∶1、和18∶1占总脂肪酸的比例均显著提高,其中16∶0和18∶1均在限制96h达到最高值,分别提高了24.77％和95.27％,而20∶4和20∶5则显著降低.添加钨酸钠培养时,16∶0、16∶1、和18∶1占总脂肪酸的比例均显著提高.在钨酸钠浓度为0.1mmol/L时,与对照组相比,18∶1含量提高了1.13倍.该结果与培养基限氮培养时一致.因此,添加钨酸钠可实现氮限制.本研究旨在通过改变培养条件,探索微藻生物量积累后富集油脂的可能性,为微藻生物柴油大规模生产提供理论基础.     

温度对四种产油微藻生长和油脂特性的影响

本文采用气相质谱联用技术对三株海水微藻—三角褐指藻(Phaeodactylum tricornutum,CCMM2012)、小球藻(Chlorella vulgaris,CCMM4004)、微拟球藻(Nannochloropsis sp.,CCMM6004),和一株淡水微藻—栅藻(Scenedesmus quadricauda,CCMM4002)在不同温度下的生长及油脂变化规律进行研究。结果表明:三角褐指藻、小球藻和栅藻在20℃下的油脂产率最大,分别为2.94、5.79和5.83mg/L/d,它们在20℃的培养条件下比较适合应用于生物能源开发;而微拟球藻在25℃下油脂产率最大,达6.45mg/L/d,因此此温度下更适合用于生物能源开发。三角褐指藻在15℃条件下DHA和EPA含量最多,为16.47%,而微拟球藻在25℃下DHA和EPA最多,为22.74%;因此三角褐指藻和微拟球藻在15℃和25℃下均比较适合应用于多不饱和脂肪酸的开发,而小球藻和栅藻的EPA和DHA含量在三个温度下普遍较少,不适合用于多不饱和脂肪酸的开发。     

Δ6-去饱和酶和C20-延伸酶抑制乳腺癌细胞MCF-7增殖的研究

为探讨外源基因Δ6-去饱和酶与C20-延伸酶基因对肿瘤细胞增殖的抑制作用,本研究选取了微拟球藻(Nannochloropsis oculata)作为研究对象,对其Δ6-去饱和酶与C20-延伸酶基因进行了逆转录PCR扩增,并将获得的上述2个基因的编码区与真核表达质粒pEGFP-C3构建重组表达质粒,转染乳腺癌细胞MCF-7,以pEGFP-C3为对照,培养48h后,在荧光显微镜下观察转染细胞中的GFP荧光信号以判断重组质粒表达情况,荧光实时定量PCR分析转染细胞中外源基因的转录水平,MTT比色法检测外源基因对MCF-7细胞的增殖抑制程度,高效气相色谱检测转染细胞中多不饱和脂肪酸(Polyunsaturated fatty acids,PUFAs)的含量变化。结果表明2个外源基因均可在MCF-7细胞中表达,并能有效地抑制MCF-7细胞的增殖,改变MCF-7细胞中2种PUFAs的相对含量,且n-3PUFAs与n-6PUFAs的比值升高。推测过表达的Δ6-去饱和酶与C20-延伸酶可能通过改变乳腺癌细胞MCF-7细胞膜中PUFAs的相对含量,达到抑制乳腺癌细胞MCF-7增殖的效果。     

利用市政污水厂尾水培养产油微藻——营养盐去除与生物质生产

将1株产油淡水微藻——微拟球藻(Nannochloropsis sp.MASCC 11)分别接种到青岛市2家市政污水处理厂(STP)的尾水中,根据其生长、油脂产率和营养盐去除情况,评价了利用STP尾水培养微藻以生产富油的藻生物质同时深度净化尾水的可行性。结果表明,团岛污水处理厂(TD-STP)和李村河污水处理厂(LC-STP)尾水中无机氮和磷酸盐的浓度虽然远低于BG11培养基,但仍能支持微藻生长,而且以未经稀释的尾水更具优势,培养8 d后,藻生物量分别达到BG11培养基中生长微藻的65.23%和44.77%。STP尾水经稀释后处于营养盐缺乏状态,有利于藻细胞内脂质积累,但是油脂产率最大值(10.5 mg·L^-1·d^-1)仍出现在未经稀释的TD-STP尾水中,为未稀释LC-STP尾水的1.37倍。LC-STP尾水中微藻的油脂产率较低,可能与该处理厂接纳工业废水而在尾水中残留较多有害物质有关。在微藻的直接和间接作用下,TD-STP和LC-STP尾水中磷酸盐的去除率分别达到94.5%和100%;无机氮的去除率较低(分别为59.2%和45.4%),与尾水中初始N/P较高有关。上述结果表明,与接纳工业废水的污水厂相比,处理生活污水的污水厂所排尾水较适于培养产油微藻,能够实现产油微藻低耗培养与尾水深度净化相耦合。     

海洋微拟球藻对共培养三角褐指藻的分子生理学响应机制

本研究运用多物种混合转录组测序(msRNA-seq)法分析了对数生长期海洋微拟球藻响应相同细胞数指数末期三角褐指藻共培养的生理机制。两种藻的细胞总数在8 d内基本不变。三角褐指藻转录组结果中存在与生长有关的基因的表达,且难以与响应共培养的生理过程区分。因此,我们只分析微拟球藻响应共培养的转录组变化及其揭示的生理学机制。分析发现在共培养的初始24 h内共有8 235个基因表达,其中,809个为显著差异表达基因,351个下调表达,458个上调表达。这些差异基因被富集到7条KEGG通路中。其中,在DNA复制和同源重组通路上所富集的基因呈下调表达,而在氨基和核苷酸糖代谢通路、Focal adhesion、PI3K-Akt、cAMP、ErbB信号通路上所富集的基因呈上调表达。结果表明海洋微拟球藻响应三角褐指藻共培养时发生了一系列生理学变化。这是应用多物种混合转录组测序分析微藻间互作的初步尝试,建立的方法也适用微藻和其它微生物的互作机制研究。     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Evaluation of the Risk of Marine Slope Instability: A Pseudo-3D Approach for Application to Large Areas

This article presents a methodology developed to evaluate the instability of submarine slopes that extend over a large area. Special attention was paid to (1) the complex geometry (bathymetry) and the expanse of the slope, (2) the heterogeneity of the sediment, and (3) the distribution of the pore pressure. The safety factor was considered as a spatially varying quantity. The General Formulation (GLE, Fredlund and Krahn 1977), which fully satisfies equilibrium conditions, was used for evaluating the stability of the marine slope. The submarine slope failure, which occurred on 16 October 1979 during the construction of the new Nice airport, was studied in order to test the developed model. Geotechnical parameters were taken from experimental tests carried out by IFREMER on 19 cores extracted at different depths (from 27 m to 1300 m) (Cochonat, Bourillet, and Savoye, 1993; Mulder et al., 1994). Many scenarios were proposed in order to explain the cause of the Nice slope failure (Habib, 1994). In this article, two of those scenarios were tested. Simulation results are presented and discussed.