经酶修饰和未经酶修饰的鹌鹑红细胞对甲壳动物血清凝集素凝集活性的差异研究

为寻找凝集素作为分子探针提供基础资料,用12种甲壳动物血清抽提液对天然的或经酶修饰的鹌鹑红细胞进行凝集试验。实验结果表明,经蜗牛酶修饰后的鹌鹑红细胞的凝集作用发生了变化,与未经酶处理的鹌鹑红细胞相比,凝集活性提高的有日本沼虾（Macrobrachium nipponense）等7种,凝集活性下降的有罗氏沼虾（Macrobrachium rosenbergi）等2种。凝集素对动物红细胞的凝集可看作是与这些细胞表面的多糖或糖蛋白——即受体的识别性鲒合,这表明鹌鹑红细胞表面具有12种凝集素的受体,且大多数受体都受到酶修饰的影响,从而在凝集活性上表现出差异。     

脊条褶虾蛄血清及肌肉提取液凝集活性的比较

利用血凝试验及糖抑制试验测定脊条褶虾蛄的血清及肌肉提取液的凝血活性及糖抑制专一性，同时进行热稳定性、pH及Ca^2 影响试验。结果显示：其血清能凝集12种红细胞，且其凝集效价高于肌肉提取液（兔、蛇、鲫鱼除外）。血清对鹌鹑红细胞的凝集可被D－果糖、D－半乳糖和蔗糖所抑制，最小抑制浓度均为200mmol/dm^3，其凝集活性均依赖于Ca^2 ，在pH值为5.0-9.0范围内较稳定，经40℃保温10min后活性完全消失；肌肉提取液不被7种糖抑制，在pH值为4.0-10.0、温度为40－90℃范围内均具活性，说明有很强的耐热性，其凝集性不依赖于Ca^2 。以上结果表明：脊条褶虾蛄血清与肌肉提取液均含有凝集素，且凝集素的种类不同。     

绒螯蟹凝集素的红细胞凝集活性分析

利用血凝试验及糖抑制试验测定一种绒螯蟹的血清及肌肉提取液的凝血活性及糖抑制专一性,同时进行热稳定性、pH及Ca^2 影响试验。结果显示：血清只能凝集9种红细胞,肌肉提取液能凝集12种红细胞。血清对鹌鹁红细胞的凝集可被乳糖、D-甘露糖、D-果糖、D-半乳糖4种糖所抑制,最小抑制浓度均为200mmol／L,其凝集活性均依赖于Ca^2 ,在pH为6．0～7.0范围内较稳定,经50℃保温10min后活性完全消失。肌肉提取液只被D-甘露糖抑制,在pH为4．0～10．0、温度为4℃～90℃范围内均具活性,说明有很强的耐热性,其凝集活性不依赖于Ca。以上结果表明：血清与肌肉提取液均含有凝集素,且凝集素的种类不同。     

毛蚶血清凝集素的凝集活性

以毛蚶为实验材料,对其血清中的凝集素进行研究.毛蚶血清凝集素对人的A,B,O血型红细胞、鸡和小鼠的红细胞均有凝集作用,凝集效价分别为256,256,8,16,64,同时它还能对白色念珠菌、啤酒酵母、溶藻胶弧菌等微生物具有凝集作用.毛蚶血清凝集素具有一定的pH值稳定性和热稳定性.在选用的12种单糖和寡糖中,L-鼠李糖、L-树胶醛糖、麦芽糖、D-半乳糖、蔗糖对毛蚶血清的凝集活性有明显的抑制作用.用弧菌对毛蚶进行免疫刺激时,其血清对鸡红细胞的凝集效价明显增加.     

外源凝集素──水产动物御敌的有力兵器

外源凝集素是非免疫起源的热敏蛋白质或糖蛋白，由于其多价构型及对持定细胞多糖具结合亲和力，它们选择凝集某些细胞（包括脊椎动物血球及一些病原微生物）和沉淀某些复杂碳水化合物；其凝集活动常被单糖所抑制，有的却需某些二糖、三糖或多糖。外源凝集素分离自广泛的低等和较高等的生物。一些地区水产养殖业受挫，因素较多，但对发病机理认识之缺乏和调动养殖对象本身防病积极性之不足，是其重要原因。外源凝集素可在诸如凝集外来细胞，调理作用等的防御活动中扮演识别因子，协助一些生理活性物发挥作用，参与吞噬、胞囊、凝固、止血及创伤修复等作用。在生物学、细胞学、生物化学、医学和食品科技上有广泛用途。迄今外源凝集素的许多性能并未全清，在自然界中的精细生理作用仍是个谜。本文论述外源凝集素的定义、性能及用途，以提请有关人士重视。     

斑纹鲟凝集素(CFL)的初步研究Ⅱ.CFL的分子组成及性质鉴定

采用生化方法对斑纹鲟(Charybdis feriatus)凝集素进行了初步研究.结果表明,斑纹鲟的血清中有动物红细胞和微生物细胞凝集活性的凝集素(Charybdis feriatuslectin,CFL),其活力表现依赖于Ca2+,并为多种糖所抑制;CFL对40℃以上的温度敏感,其活力在pH6.0~8.0内稳定.经巯基乙醇处理和未经巯基乙醇处理的CFL在SDS-PAGE上均为一条蛋白带,说明斑纹鲟凝集素不含二硫键,且只有一种亚基,分子量为40.8 kDa,CFL氨基酸组成分析表明其富含酸性氨基酸.     

双壳贝类血清中凝集素凝集性能初步研究——对脊椎动物血细胞的凝集作用

在多种贝类血清中发现有可凝集脊椎动物血细胞的因子——凝集素。栉孔扇贝（Ｃｈｌａｍｙｓｆａｒｅｒｉ）血清中的凝集素可凝集鸡、鹌鹑、小鼠等多种动物血细胞,但对鳝鱼血细胞不发生作用。该凝集素具有较强的热稳定性,１００℃处理４５ｍｉｎ仍具活性;并具有广泛的ｐＨ范围,可在ｐＨ３～１１进行凝集作用。但其活性可被ＥＤＴＡ强烈抑制,Ｄ－甘露糖和Ｌ－鼠李糖对其活性有明显抑制作用,Ｄ－木糖和蕈糖也有轻微抑制作用。在栉孔扇贝血细胞的细胞膜上未发现有凝集鸡血细胞的活性物质。另外,用大肠杆菌和副溶血弧菌刺激栉孔扇贝后,血清的凝集作用不变。     

草鱼血清中一种新的凝集素免疫因子

于1998年5月－2000年3月，在浙江省杭州市采集草鱼，采用硫酸铵盐析和梯度聚丙烯酰胺凝胶电泳技术，从血清中分离出一种自然凝集素，对其理化和生物学性质进行研究。结果表明，该凝集素能够识别和凝集多种不同的红细胞、细菌和酵母，具有100000g离心不沉降，不被透析，耐热、耐酸、耐碱，抗DNase、RNase、SDS和乙醚，对胰蛋白酶、糖苷酶、糖氧化剂NaIO4和β－巯基乙醇敏感等特性，是一种分子量为67kD、等电点为6．2的糖蛋白分子。其活性能被半乳糖、乳糖、甘露糖和N－乙酰葡糖胺所抑制，其抗原特异性不同于草鱼凝集集抗IgM，表明两者是不同的物质。草鱼凝集素显著地促进巨噬细胞的吞噬、杀菌能力，说明是一种重要的免疫活性因子。     

两种微藻凝集素对几种不同类型细胞的凝集作用

经离子交换和分子筛层析从紫球藻（Porphyridium cruentum）和海水小球藻（Chlorella sp．）中分离纯化得到2种凝集素,研究它们对几种不同类型细胞即动物和人血红细胞、海洋和淡水微藻、细菌和真菌的凝集活性。研究结果表明,2种微藻凝集素对它们当中一些类型的细胞或种类具有不同程度的凝集活性,其中对水生聚胞藻（Synechocystis aquetilis）的凝集活性最强,最低质量浓度只需0．0313g／L。     

海藻凝集素研究进展

凝集素是一大类能够凝集生物细胞的蛋白或糖蛋白 ,广泛地存在于许多生物体内 ,在生物体的配子识别和生殖细胞融合中起着重要作用 ;许多生物凝集素表现为可以凝集人或动物的血细胞、蓝藻细胞、生殖细胞 (配子 )等多种细胞 ,同时某些凝集素具有抗病毒 ,促进淋巴细胞分裂 ,抗血小板凝集［２］和抗菌的作用。植物中较早发现的凝集素是陆生植物凝集素 ,其最早的应用是用来鉴别人的血型。１９６６年 ,Ｂｏｙｄ等人在一些热带海藻中发现了海藻凝集素的存在 ,此后Ｂｌｕｎ ｄｅｎ和Ｒｏｇｅｒｓ等对英国沿海的海藻检测了提取物的凝集活性 ,发现只有…     

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.     

A Review of Some Environmental Issues Affecting Marine Mining

This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.     

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.     

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces

The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.     

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.