一株产低温右旋糖苷酶海洋细菌的筛选和鉴定

从连云港海域筛选得到一株产低温右旋糖苷酶的菌株LP621,经形态特征、生理生化特征以及16S rDNA序列分析和鉴定,该菌株为Pseudoalteromonas tetraodonis.该茵产生低温右旋糖苷酶的最适作用温度为30℃,在80℃保温2.5 h后该酶仍具有40％以上的活性.目前尚无Pseudoalteromo...     

中国对虾体内1株益生菌的筛选与初步鉴定

为给对虾专用益生菌制剂的研制与应用提供理论依据和基础数据,研究了从白斑病毒(WSSV) 耐过中国对虾(Fenneropenaeus chinensis)肠道中分离的1株海洋细菌B12的益生特性和安全性,并结合形态观察、生理生化特征和16S rDNA序列分析对菌株B12进行了分类鉴定.结果表明:菌株B12能抑制对虾致病性哈维氏弧菌 (Vibrio harveyi)和副溶血弧菌(V. parahaemolyticus)的生长,不分泌溶血素.对β-内酰胺类、头孢类、氨基糖苷类、喹诺酮类抗生素均敏感;对大环内酯类、四环素类抗生素均耐药;对糖肽类抗生素中度敏感.毒性试验表明菌株B12对中国对虾幼体没有明显毒副作用.该菌为革兰氏阴性可动杆菌,鞭毛极生,菌体大小为(0.5～0.6)×(1.1～1.2) μm,接触酶、氧化酶阳性,葡萄糖发酵产酸,能还原硝酸盐,产淀粉酶,不产明胶酶,不能利用丙二酸.16S rDNA的部分序列分析显示菌株B12与嗜盐单胞菌(Halomonas sp.)SB J85具有98.15%的相似性.形态观察、生理生化特征和16S rDNA序列分析证实B12为嗜盐单胞菌属(Halomonas sp.).     

极地产适冷脂肪酶菌株的酶学性质研究

从南北极环境样品中分离到7株产脂肪酶的细菌,经16SrDNA序列分析表明,这些细菌分别属于假交替单胞菌属（Pseudoalteromonas）和嗜冷杆菌属（Psychrobacter）．采用p-NPP法对这7株细菌所产的脂肪酶进行酶学性质研究,结果显示这些酶的最适作用温度在30～40cC、最适作用pH值在7—8之间,在低温下能保持较高的剩余活力,对热敏感,属于适冷脂肪酶．其中假交替单胞菌（Psychrobacter sp．7342）所产脂肪酶具有低温下酶的剩余活力高、有效作用温度和pH范围广、热稳定性较好及对多种金属离子抗性强等特点．该菌株能利用多种单一氮源和碳源产酶,最适产酶温度为25℃．在此基础上进行正交实验分析得到了该菌株的最佳发酵条件为：蛋白胨和淀粉含量各为1．33％,酵母膏含量为0．3％,温度为25℃．     

一株海洋几丁质酶产生菌的筛选及其产酶条件的初步研究

从胶州湾的海泥中分离到一株几丁质酶高产菌株。经16SrDNA序列分析,认为该菌属于假交替单胞菌(Pseudoaltermonas),并将其命名为SS01。对该菌产几丁质酶的最佳培养条件进行了研究,发现与其它几丁质酶产生菌相比,SS01菌株的最适产酶温度较低,酶活较高。在Zobell2216E培养基中,SS01菌株培养9h进入稳定期。胶体几丁质可诱导该菌几丁质酶的产生。在几丁质培养基中,SS01菌株产酶的适宜条件是:培养温度24℃,培养基起始pH7.0左右,蛋白胨为N源(5g/L),胶体几丁质为C源(5g/L),170r/min振荡培养130h,酶活可达116.2U/mL。     

壳聚糖酶高产菌株的筛选和发酵条件的研究

从采集的土样中分离到1株产壳聚糖酶能力较强的菌株OU01,并对OU01进行了16S rDNA序列、形态及生理生化鉴定分析。16S rDNA序列分析表明该菌属于微杆菌属;该菌的形态特征与生理生化鉴定结果表明该菌与Microbacteriumsp.的相似性最高;因此将其初步鉴定为微杆菌属(Microbacterium)。同时对该菌的发酵条件进行了初步研究:该菌的最适培养基组成为(g/L):chitosan 10,(NH4)2SO420,MgSO4.7H2O 1.3,K2HPO4.3H2O 1.4,Glucose 1,Yeast extract 3,NaCl 5,起始pH=6.30。最适发酵温度为30℃,最佳发酵时间为96 h,在上述最优条件下,该菌株产酶达到118 U/mL。Microbacteri-umsp.OU01菌株为壳聚糖酶的研究和应用提供了新的来源。     

产碱性纤维素酶海洋细菌的筛选、鉴定及酶学性质研究

用CMC平板筛选方法,从青岛近海海域海水中分离出一株产碱性纤维素酶的海洋菌株QM11,经16S rDNA鉴定,该菌株为Cytophaga fucicola.对该菌的生物学特性研究表明,其最适生长温度为27℃,生长温度范围为4～48℃,为耐冷菌;在pH7.0～8.0、含3.0%NaC1的培养基条件下,最适宜菌株生长和产酶;QM11所产碱性纤维素酶最适反应温度为40℃,最适反应pH为9.0,在碱性条件下具有较高的酶活性和较好的稳定性.Mn2+、Fe3+对酶反应具有促进作用,Cu2+、Pb2+对酶反应具有抑制作用.     

一株海藻多糖降解菌的分离鉴定及产酶条件优化

从大型褐藻藻体分离获得一株具有高效降解琼胶和褐藻胶能力的革兰氏阴性菌菌株ST-6。16S rDNA序列分析结果表明,该菌株与海绵假单胞菌的相似度达到99%,NJ法构建系统进化树也与海绵假单胞菌归为一类,鉴定为海绵假单胞菌Pseudomonas pachastrellae ST-6。在2216E培养基、30℃培养条件下,海绵假单胞菌ST-6的生长曲线表明,接种10~48 h为菌株的指数生长期,48~72 h为生长稳定期。产酶结果表明,菌株ST-6在指数生长期时菌液的胞外琼胶酶相对酶活力较高,在接种48 h时,菌液的琼胶酶相对酶活力最高为249.15 U/m L。此外,发现菌株ST-6的琼胶酶和褐藻胶酶的分泌类型分别为非诱导型和诱导型。采用单因素分析法对其生长和产酶条件进行分析,结果表明,海绵假单胞菌ST-6最适生长条件为:温度25~35℃,33值5~9;最适产琼胶酶条件为:温度30℃,33值为7,琼胶浓度0.3%。最适产褐藻胶酶条件为:温度35℃,33值为9。在温度30℃、339和褐藻酸钠浓度0.15%的培养条件下,海绵假单胞菌ST-6获得最高胞外褐藻胶酶相对酶活力为135.54 U/m L。     

一株产褐藻酸多糖的海洋假单胞细菌Pseudomonas sp.QDA的筛选和鉴定

根据已获褐藻酸多糖生物合成基因簇中褐藻胶裂解酶基因(αlgL)的序列设计特异性引物，利用PCR技术从海洋微生物中筛选到1株能够分泌胞外多糖的细菌。采用形态学观察和16S rDNA序列分析鉴定该菌株，结果为假单胞属细菌，命名为Pseudomonas sp.QDA；系统发育树显示该菌株与P.putida亲缘关系最近。菌株产生的胞外多糖可被褐藻胶裂解酶(AlgL)降解，并在紫外234nm处检测到特征性吸收，初步证明含有褐藻酸多糖。     

一株产琼胶酶海洋细菌的分离与鉴定

为获得琼胶酶活性高产菌株,对采集的海水样品进行了产酶微生物的分离、筛选和鉴定。经过平板培养预筛和两次摇瓶培养筛选,从浙江省舟山市普陀区近海海水样品中分离到一株琼胶酶产生菌G-5,该菌株液体培养产酶活力可达到413.8 U/mL。G-5菌株的菌落呈乳白色、半透明、表面湿润;菌体革兰氏染色阴性,大小0.58~0.69 μm1.50~2.26 μm;光学显微镜下呈短杆状,略有弧形。G-5菌株的16S rDNA序列与NCBI数据库中15个弧菌属（Vibrio）菌株的16S rDNA有98%的同源性,可以确定G-5菌株是一株弧菌（Vibrio sp.）。     

抗硅藻附着活性细菌的筛选、鉴定与发酵条件优化

从美国华盛顿州圣璜岛海域的8 种海绵样品的120 株共附生微生物中, 筛选出11 株细菌的粗提物能有效抑制硅藻附着。其中683 号菌株活性最高, 对5 种受试硅藻的平均抑制率达到98.0%。结合形态学特征和扫描电镜观察, 以及16S rDNA 序列分析, 鉴定该菌株为短小芽孢杆菌Bacillus pumilus。并采用正交试验对该菌株进行发酵条件优化, 结合粗提物的产量和抗硅藻附着活性进行统计学分析,确定了该菌株的最佳发酵条件是: 发酵温度25℃, pH 7.5, NaCl 浓度19.45 g/L, 蛋白胨浓度5 g/L。     

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.     

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.     

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.     

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.