深海沉积物宏基因组文库中产蛋白酶克隆CAPRO2的筛选及酶学性质分析

利用选择性筛选培养基从所构建的深海沉积物宏基因组文库中筛选得到一株产蛋白酶的克隆（CAPR0002）,对其进行了酶学性质分析．结果表明该酶的最适作用温度为65cc,最适作用pH值为9．0．该蛋白酶具有较好的热稳定性,在40cC以下的温度中可长期保持稳定,在50℃中处理6h后仍能保持60％的活力,在60℃下保温30rain后仍能保持约60％的活力．Ca^2＋、Mg^2＋、sr^2＋、co^2＋对该蛋白酶有明显的促进作用,而且ca^2＋的存在可明显提高该蛋白酶的热稳定性,ca^2＋、sr^2＋、c0^2＋这3种离子均在3．0mmol／dm^3。浓度时具有最高的促进作用,当浓度高于3．0mmol／dm’时,这3种离子对酶活力的促进作用减弱．Hg^2＋、Fe^2＋、cu¨对酶有明显的抑制作用．CAPR02蛋白酶在pH值为7。5～9．5时活力较高,pH值为7。5时可保持约80％的活力,pH值为9．5时保持60％的活力,而在pH值高于9．5的条件下酶活力下降较快,pH值为10．0时活力降为约15％,表明CAPR02属于碱性蛋白酶．丝氨酸蛋白酶抑制剂PMSF、E一64和AEBSF对CAPR02蛋白酶均无抑制作用,显示该酶不属于丝氨酸蛋白酶,而EDTA对酶有明显的抑制作用,表明该酶属于金属蛋白酶．     

中华绒螯蟹鳃上皮Na+-K+-ATPase性质的研究

本文研究了中华绒螯蟹鳃上皮Na^ -K^ -ATPase的性质，并比较了各对鳃丝Na^ -K^ -ATPase的活性大小。结果表明：中华绒螯蟹鳃上皮Na^ -K^ -ATPase的最适温度为40℃，温度高于45℃时酶活急剧下降；最适pH为8．0，并且其活力对pH的变化非常敏感，当pH小于7．5或大于8、25时酶活急剧下降；最适底物和Na^-，K^ ，Mg^2 浓度分别为1．5，75，15，6mmol／l；反应介质中乌本苷浓度达到2mmol／l时，Na^ -K^ -ATPase的活力完全被抑制；中华绒螯蟹后3对鳃丝Na^--K^ -ATPase的活力极显著高于前5对鳃丝的酶活力。     

褐藻酸降解酶的制备及其性质研究

通过培养褐藻酸降解菌交替单胞菌(Alteromonas sp．)菌株H-1使其产酶，研究了该酶的性质。结果表明，该菌在25℃培养72h时产酶量最高。褐藻酸酶作用的最适底物质量分数为1％～2％。最适pH值为7．5，最适反应温度为40℃，温度升高酶活力急剧下降。     

褐牙鲆鳃丝Na+-K+-ATPase性质的研究

研究了褐牙鲆 (Paralichthysolivaceus)鳃丝Na K ATPase的性质。结果表明 :褐牙鲆鳃丝Na K ATPase活力随着反应温度、pH的增加均呈现峰值变化 ,其最适反应温度为 3 0～ 3 5℃ ,高于 40℃酶活力急剧下降 ,至 5 0℃酶失活 ,而最适pH为 7.5～ 8.0之间 ,pH <7.5或 >8.0时酶活力急剧下降 ,低于 6.0酶活则被完全抑制 ;在本试验设计的反应时间和底物浓度范围内 ,随着时间和底物浓度的增大 ,酶活力的变化均为逐渐升高 ,且上升趋势逐渐变缓 ;反应介质中Na ,K ,Mg2 的最适浓度分别为 180 ,3 0 ,6mmol/L ,并且当K 或Mg2 浓度为 0时 ,酶活力均接近于 0。抑制剂乌本苷对鳃丝Na K ATPase活力表现为显著性抑制 ,在乌本苷浓度为 2mmol/L时 ,酶活力完全被抑制。     

产低温纤维素酶海洋嗜冷菌的筛选及研究

从黄海的深海海底泥样中筛选出一株产纤维素酶的海洋细菌，初步鉴定为革兰氏阴性杆菌。该菌既能产生羧甲基纤维素酶，又能降解微晶纤维素，互有淀粉酶活。对该菌生长特征及所产纤维素酶的性质进行了初步研究。此菌最适生长温度为20℃，最高生长温度为40℃，在0℃也能生长，是典型的嗜冷菌。该菌所产纤维素酶最适反应温度为35℃，10℃仍有较高酶活，最适pH值为6．0，属酸性酶。     

褐藻酸降解菌A7的发酵及产酶条件研究

以海藻废弃物堆肥中分离到的薄壁杆菌属（Gracillibacillus）的褐藻酸降解菌A7为研究对象,对该菌的生长及产酶条件进行了研究。结果表明,该菌的最适产酶条件为：温度30℃,海藻酸钠的质量分数0．5％,pH9．5,NaCl浓度0．5mol／L,以蛋白胨为主要氮源。在最佳条件下培养96h达到最高酶活力12．79U／mL。     

对深海适冷菌Pseudomonas sp. SM9915分泌不同适冷蛋白酶的研究

从1855m深的海底泥样中分离到一株产适冷蛋白酶的适冷菌Pseudomonas sp.SM9915，经测定发现该菌株的最适生长温度为20℃，最适产酶温度为15℃，粗蛋白酶的最适酶温度为40℃。在此基础上，采用硫酸铵沉淀和分子筛层析方法对P.sp.SM9915分泌的蛋白酶进行了分离纯化。结果表明，P.sp.SM9915至少分泌三种适冷蛋白酶，并且三种蛋白酶的性质有所不同。这三种蛋白的最适pH分别为8．0、9．0、7．0。最适酶海温度分别为45℃、40℃、40℃；其热稳定性也有明显的差别，40℃下保温，酶活的半衰期分别为11min、5min和27min，表明这三种蛋白酶对低温的适应进化是不同步的。     

超嗜热古菌耐热酸性α-淀粉酶的发酵条件和酶学性质研究

对一株分离自深海热液口的超嗜热古菌(Thermococcus sp.HJ21)菌株进行了α-淀粉酶发酵条件的优化和酶学性质的研究.该菌株发酵9h后到达产酶高峰,产酶温度范围为60-90℃,其最适产酶温度为80℃.产酶pH范围为5.0-9.0,最适产酶pH为7.5.产酶NaCl浓度范围为0.5-4.0%,2.5%为最适宜NaCI浓度.糖原、淀粉、麦芽糖、酵母膏和蛋白胨促进产酶.该菌株产生的α-淀粉酶的分子量为51.4 kDa,酶的最适作用温度为95℃,在100℃仍有60%的酶活力.酶在90℃的半衰期为5 h,在100℃ 2 h仍有40%的残余酶活,酶的热稳定性不依赖Ca2+.酶的最适作用pH为5.0,pH 4.5仍有80%的酶活力,pH在5.5-7.0较稳定(80℃ 4 h).金属离子1 mmol/L的Mg2+、Co2+、Sr2+、Ba2+、K+、Na+对酶有激活作用,Cu2+、Pb2+、Hg2+、zn2+、Al3+对该酶均有抑制作用.     

温度、pH对日本沼虾血清酚氧化酶活力及稳定性的影响

以日本沼虾（Macrobrachium mipponense)为材料，研究温度，pH对其血清酚氧化酶活力及稳定性的影响。试验以L－多巴为作用底物，测得酚氧化酶的最适温度为40℃，大于或低于该值，酶活力均迅速下降，同时该酶在40℃以下表现出较高的热稳定性；该酶的最适pH值为7．0；在pH6－8范围内具有较高的活性，最稳定的pH为8．0。     

环境因子对栉孔扇贝血淋巴中谷胱甘肽转硫酶活性的影响

采用分光光度法研究了环境因子对栉孔扇贝（Chlamys farreri）血淋巴中谷胱甘肽转硫酶（GST）活性的影响。结果表明,血清和血细胞中都存在GST,且血细胞中酶活力高于血清。血细胞中GST的适宜温度范围是20～35℃,最适温度为30℃,在60℃时酶活力完全丧失。该酶的适宜pH为7—8,最适pH为7．5。将血细胞裂...     

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,     

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.