耐盐基因转化蓝藻Synechococcus sp. PCC 7942研究

将从极端耐盐的假单胞杆菌中克隆得到的3个基因，即转录调控因子基因，NADH脱氢酶Ⅱ基因和磷酸甘油磷酸酯酶基因转入淡水蓝藻Synechococcus sp.PCC 7942中，使受体藻对NaCl的耐受性从低于2．5％显著提高到4．5％，进一步证明了这3个基因确定与生物的耐盐性密切相关。本实验为进一步培育耐盐经济作物奠定了基础。     

假单胞菌(Pseudomonas sp.cn 4902)甘露醇-1-磷酸脱氢酶基因克隆及表达

参照几种生物的甘露醇—1—磷酸脱氢酶基因(mtl D)的序列设计引物，以极端耐盐的假单胞菌(Pseudomonas sp．cn 4902)的总DNA为模板，采用PCR扩增、构建重组高效表达载体以及生物信息学研究等方法，进行基因克隆、表达及功能定性等研究。结果表明，克隆获得一长为1149bp的基因。经蛋白质保守区域研究，初步判别该基因为mtl D结构基因。将该基因与pBV220质粒构建成高效表达原核重组载体pBH。SDS—PAGE电泳表明，含pBH的转化子产生特异的、分子量约为41kD的蛋白带，表达量约占菌体可溶性蛋白6．7％。转化子的耐盐水平比对照提高了约1／5。在含0．9mol／L NaCl的液体培养基中，转化子培养24h后其生物量约是对照的10．2倍，甘露醇含量约是对照的4．1倍。可见，假单胞菌的甘露醇—1—磷酸脱氢酶基因是一个重要的耐盐相关基因，该基因已在GenBank登记，代号为AY112696。     

沼泽红假单胞菌(Rhodopseudomonas palustris)核酮糖-1,5-二磷酸羧化酶/氧化酶基因克隆及其在大肠杆菌中的表达

核酮糖-1,5-二磷酸羧化酶/氧化酶(RubisCO)(EC4.1.139)是光合细菌通过卡尔文循环固定二氧化碳的关键酶。本文采用PCR方法,从沼泽红假单胞菌株No.9中克隆到RubisCO基因(cbbM)序列(该序列已提交GenBank,登录号:GU061327)。采用同源建模法,建立了该RubisCO蛋白的三维结构模型,预测其活性位点。将cbbM基因亚克隆到表达载体pTV118N上,构建表达质粒pTV-CBBM,转化大肠杆菌BL21(DE3),获得表达菌株BL21(DE3)/pTV-CBBM,该菌株经IPTG诱导表达后,进行SDS-PAGE检测。采用气相色谱法测定破菌上清中的RubisCO酶活。结果表明:①cbbM基因编码461个氨基酸,与沼泽红假单胞菌株DCP3和DH1的RubisCO蛋白序列相似性分别为98%和99%;②推测沼泽红假单胞菌No.9中RubisCO蛋白的活性中心由Asn112、Lys192、Asp194、Glu195、His288、Arg289、His322、Gly424、Ser369、Gly370和Gly394等氨基酸残基组成;③重组蛋白分子量约为50kDa左右,与预测相符;④破菌上清中的RubisCO酶比活高于原始菌株中的酶活,说明目的基因在大肠杆菌中得到了有效表达。     

6-磷酸山梨醇脱氢酶(gutD)基因克隆、测序和表达

本研究根据6-磷酸山梨醇脱氢酶基因(gutD)两端序列设计引物，以假单胞杆菌(Pseudonmonas XM)的总DNA为模板通过PCR的方法克隆gutD基因并进行序列分析，将克隆得到的gutD基因与原核表达载体pBV220连接并转化大肠杆菌(Escherichia coli)JM101后检测其蛋白表达及菌株生长耐盐性。     

白骨壤铜锌超氧化物歧化酶基因片段的克隆与序列分析

以红树植物白骨壤(Avicennia marina)基因组DNA为模板，根据超氧化物歧化酶基因保守序列设计特异引物进行PCR扩增，得到特异基因片段。回收该基因片段，与pMD18-T载体连接,并转化到感受态大肠杆菌ER2566细胞，获得铜锌超氧化物歧化酶基因片段的克隆。序列分析表明白骨壤铜锌超氧化物歧化酶基因片段含4个外显子和3个内含子，编码78个氨基酸,与水稻、玉米、红薯和白杨相应氨基酸序列的同源性分别为83．3％，84．6％，84．6％和87．2％。     

产壳聚糖酶菌株选育及培养条件优化

以假单胞菌Y8．0为出发菌株,分别通过亚硝基胍(NTG),Co^60,UV(紫外)诱变,采用透明圈法筛选,获得了产壳聚糖酶较好的突变菌株假单胞菌Y8,其所产酶活力达到3．0U／mL,酶活力提高近6倍,并具有较好的遗传稳定性。3种诱变方法中,UV诱变效果最好。对假单胞菌Y8产壳聚糖酶培养条件进行研究,得到1个比较优化的培养条件为：pH值6．5,温度32℃,壳聚糖3g／L,酵母膏0．3％,培养时间3d。不同金属离子及不同诱导物对酶合成的影响表明：Fe^2 ,Mg^2 激活作用显著。而Zn^2 ,Mn^2 则具有一定的抑制作用,壳聚糖和氨基葡萄糖对壳聚糖酶的产生都有较好的诱导作用。     

宁波沿海陆源排污口假单胞菌属(Pseudomonas)分布特点

采用高通量454焦磷酸测序方法对宁波沿海2个重点排污口、8个一般排污口的20个站位水样进行分析, 得到2011年3月、5月、8月、10月份各排污口假单胞菌属的分布情况。结果表明, 宁波沿海陆源排污口中存在较多的假单胞菌属。在检出的假单胞菌属中, 维罗纳假单胞菌(Pseudomonas veronii)和莓实假单胞菌(Pseudomonas fragi)的含量相对较多, 分别占56.72%、13.904%; 排污口中假单胞菌属的数量存在季节性差异, 3月份、5月份假单胞菌的数量相对较多, 8月份和10月份较少, 推测与季节性温度变化有关; 假单胞菌属的含量与排污口的主要污染物有关, 氨氮含量较高的排污口假单胞菌属的含量更高。     

闽南—台湾浅滩滩上升流区拮抗菌的初步研究

研究了闽南－台湾浅滩上升流区海洋拮抗菌的生态分布、种类组成及其抗菌活性。结果表明：在该海区海水中拮抗菌占总异养菌数的１．２～９．４％，沉积物中则点４．３～１５．６％；拮抗菌的分布具有明显的季节变化，夏季拮抗菌的丰度大于其他季节，属的组成也较复杂多样。在所分离的拮抗菌中，有６株拮抗菌对多种试验菌株有不同程度的抑制能力，被鉴定为假单胞菌属、孤菌属、黄杆菌属和无色杆菌属。作者讨论了海洋拮抗菌的时空分布与     

异硫氰酸苄酯(BITC)防污损效果研究──对3种海洋细菌的抑菌作用

异硫氰酸苄酯（ＢＩＴＣ）的抑菌试验表明：ＢＩＴＣ对３种海洋细菌（假单胞菌Ｐｓｅｕｄｏｍｏｎａｓｓｐ．Ｔ１０８株,假单胞菌Ｐｓｅｕｄｏｍｏｎａｓ．ｓｐ．Ｅ２０４株和异单胞菌Ａｌｔｅｒｍｏｎａｓ．ｓｐ．Ｅ１１３株）的完全抑制浓度分别为４．０,１．０和２．０ｍｇ／Ｌ,５０％抑制该３种海洋细菌生长（相对生长率）的浓度分别为２．６７,０．３７和０．４４ｍｇ／Ｌ。     

海洋聚磷菌中核苷二磷酸激酶基因的克隆及序列分析

以海洋聚磷菌Halomonas YSR-3的总DNA为模板,用PCR法扩增核苷二磷酸激酶基因,将扩增片段克隆到pGM．T载体,转化Escherichia coli TOP10菌株,经蓝白斑筛选、菌落PCR得到阳性克隆,测序后对序列进行Blast比对分析。得到的基因序列长度为420bp,翻译后的序列与Loktanella vestfoldensis SKA53,Jannaschia sp．CCS1,Roseobacter sp．CCS2的核苷二磷酸激酶蛋白序列相似性分别为89％,86％,85％。     

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。     

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.     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.     

A Tidal Flow Model for the Gulf of Kachchh, India

A vertically integrated model has been used to study the tidal circulation and currents in the Gulf of Kachchh along the west coast of India. The model is fully nonlinear and uses a semiexplicit finite difference scheme to solve the basic hydrodynamic equations on a staggered grid. The model is forced by prescribing the tides along the open boundary of the model domain. The flow is simulated both with and without the presence of the proposed tidal barrage across the Hansthal Creek in the Gulf of Kachchh. The results show a considerable change in the behavior of the tidal flow in the presence of the barrage.     

利用中国GF-3卫星SAR和HY-2A卫星微波散射计的首次台风联合定量观测

<正>The typhoon,as a mature tropical cyclone that develops in the western part of the North Pacific Ocean with high wind speed and heavy rainfall,is one of the most lethal and costly of natural disasters for the densely populated countries of East Asia.It can be easily detected by space-borne sensors operated at microwave,visible or infrared bands(Liu et al.,2014).Synthetic Aperture Radar(SAR)is     

离子交换—原子吸收光谱法测定海水中痕量铜、铅、锌、镉、铁、锰

本文介绍了用国产D401型螯合树脂分离富集海水中铜、铅、锌、镉、铁、锰等痕量元素,并用原子吸收光谱仪测定其含量的方法。讨论了各元素的分离条件选择及干扰元素的影响,并与溶剂萃取法的结果作了比较。各元素检测的定量下限为:铜0.5μg/L、铅0.1μg/L、锌1.0μg/L、镉0.01μg/L、铁2.0μg/L、锰2.0μg/L。方法精密度在4—8％之间,回收率为90—102％。     

Biogeochemistry of Mangrove Soil Organic Matter: a Comparison BetweenRhizophoraandAvicenniaSoils in South-eastern Brazil

Soil core samples fromRhizophora mangleL. andAvicennia schauerianaStapf & Leech forests from south-eastern Brazil were analysed for their total organic matter content and their sugars, amino acid and amino sugars composition. Organic carbon and nitrogen contents were higher inAvicenniathan inRhizophorasoils. The contribution of sugars and amino acids to the total organic carbon pool was constant with depth inRhizophorasoils whereas inAvicenniasoils it increased. Spectral distribution of sugars and amino acids showed a dominance of Ca-affine monomers, particularly acidic amino acids, and the sugar arabinose. Biogeochemical indicators derived from ratios of individual sugar and amino acid monomers confirm previous studies which showed that organic matter in both soils is mainly of mangrove origin. The results further suggest accumulation of organic matter inRhizophorasoils and a continuing degradation of organic matter inAvicenniasoils. The latter may thus release more nutrients to adjacent ecosystems thanRhizophorasoils.     

A review of orange roughy Hoplostethus atlanticus fisheries,estimation methods,biology and stock structure

Orange roughy Hoplostethus atlanticus are unusual fish. They form dense aggregations that have fuelled lucrative fisheries at great depths (600–1 400 m), especially off Namibia, New Zealand and Australia. They are thought to be very long-lived (>100 years, maturity at 22 – 40 years), and to have exceptionally low natural mortality (M = 0.045–0.064 year^?1) and slow growth rates (K = 0.055–0.070 year^?1). In addition, they spawn large eggs and have low fecundity. These factors combine to make orange roughy highly susceptible to overfishing; most stocks are below 30% of pristine levels. Assessments are obtained from indices of catch rate and trawl, acoustic and egg surveys. Acoustic estimates are the most direct, but are confounded by the species' low target strength (?50 to ?53 dB)–attributable to the wax-filled swim bladder. Extracellular wax esters are stored in abundance and comprise mostly mono-unsaturated fatty acids, with low concentrations of the ω-3 fatty acid family. This unusual composition (resultant from the species' diet) ensures neutral buoyancy. Stock separation has been inferred mainly from biological studies, but genetic studies have also found differences among stocks within New Zealand and Australia. Deep-water habitat may be damaged by trawling operations and may take many years to recover, so in some quarters there is a call for a portion of suitable habitat to be set aside for preservation. Although Namibian orange roughy are shallower, smaller and younger than those in other stocks, the Namibian fishery sustained high catches for only a few years before quotas were reduced, from 12 000 to 1 875 tons. Three management lessons are suggested for developing orange roughy fisheries based on the Namibian experience: (1) imposition of catch limits during exploratory fishing; (2) starting the acoustic surveys earlier in the fishery, if possible; (3) greater reliance on trends in catch rate until a survey series has been established.