螺旋藻胞外和胞内核酸酶活性研究

通过分析比较 2个螺旋藻物种 7个品系胞外和胞内核酸酶活性 ,确定了抑制胞外和胞内核酸酶活性的方法。用液体培养基清洗两次可消除胞外核酸酶活性 ,添加 EDTA(2 m mol L-1)可显著地抑制胞内核酸酶活性。高温 (6 5℃ )处理也能显著抑制胞内核酸酶活性     

建立螺旋藻转基因体系初报

从钝顶螺旋藻单细胞克隆的制备、重组平台的 克隆、同源重组表达质粒的构建、质粒的电激转化和报告基因的表达等方面对螺旋藻转基因 表达系统进行了研究,初步建立起螺旋藻转基因体系。用次氯酸钠溶液处理获得无菌培养系 ;用钠、钙离子混合液处理,获得了可再生的螺旋藻单细胞。用含EDTA的培养基预培养和用 培养基洗涤可分别去除胞外核酸酶活性和抑制胞内核酸酶活性。以氯霉素乙酰转移酶基因替 换大肠杆菌表达质粒pBV220的抗性选择标记,同时插入系列同源重组片段和萤火虫荧光素酶 基因,构建了同源重组表达载体pBVCS01-04L。电激转化螺旋藻S6-4品系单 细胞,获得了具有稳定氯霉素抗性的培养系,并用SDS-聚丙烯酰胺凝胶电泳证实了报告基 因的表达。     

用甲基化修饰法抑制钝顶螺旋藻遗传转化中限制性内切酶对外源质粒的降解

胞内限制性内切酶降解外源DNA,是钝顶螺旋藻/节旋藻(Spirulina/Arthrospira platensis)遗传转化的难点之一。通过用EDTA螯合Mg2 抑制限制性内切酶活性的方法,对外源质粒进行了甲基化修饰。结果表明,修饰后的外源质粒可抵抗限制性内切酶3h的降解,有利于钝顶螺旋藻的遗传转化。     

钝顶螺旋藻部分原生质体及单细胞的制备与培养

于1992年1月-1994年4月，进行超声波处理方法制备钝顶螺旋藻部分原生质体以作为基因工程受体，以及制备单细胞用于固体平板克隆化培养的研究。研究结果表明：超声波以20kHz频率、15W功率作用30s，可使藻丝体断裂成15．0±1．6个细胞长度；延长作用时间，至2－6个细胞长度时，细胞壁结构遭到破坏，形成部分原生质体；继续作用，可形成少量原生质体和大量单细胞。断裂藻丝体、部分原生质体、单细胞以及原生质体均可涂布于固体培养基上再生或生长。以一定密度涂布单细胞与原生质体，能够形成彼此分开的单个克隆，可用于筛选及遗传分析。本文提供了一种节省溶菌酶的制备螺旋藻透性体的方法，超声波作用利于外源基因的导入，而涂布培养利于进一步的筛选和形成克隆。     

环境因子对鳗弧菌生长和胞外蛋白酶表达的影响

鳗弧菌(Vibrio anguillarum)是一种水产动物的重要致病菌,鳗弧菌分泌的胞外蛋白酶是该菌的致病因子之一.研究了环境因子对鳗弧菌W-1生长及胞外蛋白酶表达的影响.结果表明,鳗弧菌的最适生长温度为28℃,菌体生长量在21 h达到最高,胞外蛋白酶的活力在24 h最高.在37℃培养时,菌体生长和酶活力显著降低;添加葡萄糖、蔗糖、麦芽糖等碳源物质均能显著促进菌体的生长,但对于胞外蛋白酶表达有明显抑制作用;1 mmol/L EGTA对茵体的生长和胞外蛋白酶表达没有明显影响,而1 mmol/L的EDTA强烈抑制鳗弧菌的生长及其胞外蛋白酶的表达.添加不同浓度的氨苄青霉素对菌体的生长及其胞外蛋白酶表达有明显的抑制作用.     

利用啤酒废水养殖螺旋藻研究

利用啤酒废水养殖极大螺旋藻(Spirulina marima),研究了废水成分、氮源、藻密度和光照等培养条件对藻生长和蛋白质含量的影响。结果表明,曝气处理的啤酒废水养殖的螺旋藻,相对生长率与CFFRI培养基的几乎一致．蛋白质含量第6天最高,为0．2886g／g干质量,小于CFFRI培养基养殖的。实验确定曝气处理废水养藻的最佳条件是用NaOH调废水pH、藻初始密度取53．8mg／L、光照在1000～10000 1x范围,添加尿素或碳酸氢钠或曝气8h／d。经PSB处理的啤酒废水养殖的螺旋藻,蛋白质为0．4825g／g干质量,与CFFRI培养基养殖的相近。用光合细菌(PSB)处理的废水养藻应控制废水pH为7．0且废水与PSB的体积比为3：1。     

用改进的超声波-溶菌酶法制备钝顶螺旋藻原生质球

用改进的超声波-溶菌酶法制备钝顶螺旋藻原生质球。钝顶螺旋藻(Spirulina platensis)经超声波破碎后,用1.5 mol/L NaCl的Zarrouk培养基洗去细胞外壁的胶质鞘,然后进行酶解。酶解条件为:pH7.2的0.2 mol/L磷酸钾缓冲液,0.8 mol/L KCl,0.5%溶菌酶,28~30℃水浴震荡酶解5~7 h,获得40%以上有活力的钝顶螺旋藻原生质球。     

螺旋藻多糖的积累与抗肿瘤作用的研究

在不同温度和光强下培养极大螺旋藻438(Spirulina maxim438),得到其积累多糖规律为:不利于螺旋藻生长的温度、光照条件,会促进胞外多糖EPS(extracellular polysaccharide,EPS)的分泌,而螺旋藻最适生长条件(30℃,5000lx)与胞内多糖IPS(intracellular polysaccharide,IPS)积累的条件一致。MTT(四甲基偶氮唑盐)法体外实验证明IPS和EPS对人宫颈癌Hela细胞有抑制作用,最佳作用浓度分别为80μg/mL,100μg/mL。Caspase-3试剂盒检测经两种多糖作用后Hela细胞Caspase-3酶的变化,结果显示:处理组比对照组Caspase-3酶活性有明显提高,预示着多糖抑制肿瘤细胞的机制可能是通过Caspase途径,引起细胞的凋亡。     

南极硅藻GJ01(Berkeleya rutilans)产谷胱甘肽条件的优化

以南极硅藻GJ01(Berkeleya rutilans)为对象,分别采用紫外、可见和荧光分光光度法,研究了营养条件等因子对GJ01生长和胞内谷胱甘肽含量的影响,并对培养的GJ01细胞合成谷胱甘肽的条件进行了优化。结果表明,在单因子影响条件下,1.2g/L的碳酸氢钠对南极硅藻GJ01的生长最好,且最有利于谷胱甘肽的积累;0.8mmol/L氯化钙对GJ01的生长最为有利,而0.2mmol/L氯化钙对谷胱甘肽的产生是适宜的;维生素B_(12)和生物素对GJ01胞内谷胱甘肽的产生影响较小。正交试验表明,GJ01细胞产生谷胱甘肽的最优条件是:光照周期为16h/8h、NaHCO_3为1.6g/L、Ca~(2 )为0.4mmol/L、Cys为10mmol/L。该结果为利用南极硅藻GJ01生产谷胱甘肽提供了参考和依据。     

硒硫比值对钝顶螺旋藻有机化硒的影响及藻体中硒的形态、价格构成

在培养基中添加亚硒酸钠、硫酸钾培养钝顶螺旋藻，研究硒、硫不同克分子比（Se:S)对钝顶螺旋藻有机化硒的影响，用2，3-二氨基萘荧光分光光度法测定藻体中总硒、有机硒、4价硒及6价硒含量，分析藻体中硒的形态，价态构成。结果显示，一定范围内Se:S对钝顶螺旋藻产率影响不大，但硒浓度为3.80mmol/L、Se:S=0.812时螺旋藻产量、总硒及有机硒含量均最高，富硒钝顶螺旋藻中以有机硒为主，无机硒以4价硒为主。     

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.