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通过设计特异性引物,采用PCR扩增的方法对厚壳贻贝足腺细胞cDNA文库进行筛选,共克隆得到14条厚壳贻贝mcofp3的cDNA序列和8条mcofp6的cDNA序列,并对其基因序列及推导的氨基酸序列进行了序列比对和变异位点初步分析。结果表明,14条mcofp3cDNA序列分属于厚壳贻贝mcofp3家族的两个亚家族,其成熟肽序列变异相对活跃;而8条mcofp6 cDNA序列并无明显的亚家族划分,序列相对保守。本次实验所获得的mcofp cDNA序列初步显示了厚壳贻贝足丝蛋白家族基因的分子多样性,为将来深入了解厚壳贻贝足丝蛋白的分子多样性机制以及在此基础上开发相关的新型生物黏附剂奠定了基础。 相似文献
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从贻贝斧足肌中提取了多酚氧化酶和芳基硫酸酯酶,前者能作用于邻苯二酚和邻苯三酚,但不作用于对苯二酚;后者能作用于底物硝基邻苯二酚硫酸酯(P-NitrocatecholSulphate)。应用硫脲和NaHSO_3及KH_2PO_4和Na_2SO_3,均能抑制幼贝和成贝分泌足丝进行附着,抑制浓度分别是10—15mmol硫脲,2—4‰NaHSO_3;1—5mmol KH_2PO_4,1—3mmolNa_2SO_3,这种抑制作用是可逆的。本实验结果进一步证明贻贝足丝的形成过程是足丝酚蛋白的单宁化过程,同多酚氧化酶和芳基硫酸酯酶的作用有关。 相似文献
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翡翠贻贝足丝器的组织结构观察 总被引：1，自引：0，他引：1
用光镜和电镜技术初步探讨了翡翠贻贝Ｐｅｒｎａ ｖｉｒｉｄｉｓ足丝器的三大组成部分之间的空间结构关系，着重观察足丝柄部发生器（ＢＳＧ）的片层结构，揭示小片具有黄型的胶原原纤维电镜特征。此外，通过足丝丝部的表面结构观察，发现可用众多的突起来解释足丝表面对放射性碘的强机械吸附作用；利用足丝丝部横切片，计算出其长径约１０５μｍ，短径约４０μｍ。 相似文献
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用光镜和电镜技术初步探讨了翡翠贻贝Ｐｅｒｎａｖｉｒｉｄｉｓ足丝器（Ｂｙｓｓａｌａｐｐｒａｔｕｓ）的三大组成部分之间的空间结构关系，着重观察足丝柄部发生器（ＢＳＧ）的片层结构，揭示小片具有典型的胶原原纤维电镜特征。此外，通过足丝丝部的表面结构观察，发现可用众多的突起来解释足丝表面对放射性碘的强机械吸附作用；利用足丝丝部横切片，计算出其长径约１０５μｍ，短径约４０μｍ。 相似文献
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为研究紫贻贝(Mytilus galloprovincialis)体尺性状和体质量性状对足丝性状的影响,作者选取山东省青岛市即墨养殖区的紫贻贝为研究对象,分别测量壳长、壳宽、壳高等3个体尺性状,全湿质量、软体质量2个体质量性状以及足丝直径和足丝茎直径2个足丝性状,通过相关性分析、多元回归分析和通径分析等方法分别研究了体尺性状和体质量性状对足丝性状的影响。结果显示:所有性状间相关系数为0.678～0.892,性状间相关性达到极显著水平(P<0.01);多元回归和通径分析结果显示,壳高和全湿质量分别对足丝性状的影响最大,壳高对足丝性状通径系数分别为0.515和0.508,全湿质量对足丝性状分别为0.417和0.520;建立了体尺性状、体质量性状对足丝直径和足丝茎直径的回归方程。 相似文献
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闭壳肌的疤痕部位（AMS）是闭壳肌和壳的固定点。它是一个重要的有机-无机界面和应力分布面。尽管有一些近期的研究进展,我们对AMS组成和结构的了解仍然是有限的。这里,我们研究比较了三种双壳类动物：厚壳贻贝、栉孔扇贝、菲律宾蛤仔的AMS。结果表明这三种动物的AMS明显不同。厚壳贻贝和栉孔扇贝在AMS的壳结构珍珠片层上部有一柱状层,该层在厚壳贻贝中的结构更有规律。菲律宾蛤仔缺乏此柱状层。原子力显微镜结果显示在三种软体动物中AMS的结构比珍珠层结构更光滑。傅立叶变换红外分析结果显示珍珠层和AMS层组成成分略有不同。聚丙烯酰胺凝胶电泳蛋白分离结果显示在厚壳贻贝界面柱状层存在一种约70 kDa的蛋白。对这种蛋白的进一步分析显示其还有较高摩尔比的Asx（Asp+Asn）,Glx（Glu+Gln）和Gly。AMS的特殊结构和组成对其稳定性、粘性以及在该应力分散部位的功能有重要作用。 相似文献
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贻贝堵塞管道的防除研究 总被引：1，自引：0，他引：1
本文从三方面提供可能应用于解决管道中贻贝堵塞问题的办法:(1)砂滤法:在海水进入水管前用砂将贻贝幼虫滤去,凡颗粒小于40号筛的砂,厚度在3厘米以上,65微米的贻贝卵或幼虫即不能滤过。 (2)用三氧化二砷杀死已附着的贻贝成体,优点是贻贝不能发觉,施毒时间短而毒效大,用浓度400—100 p.p.m.时20分钟至2小时即可杀死。(3)用漂白粉使贻贝的附着足丝溶解而将其从水管中冲出的办法,含有效氯为38.6%的漂白粉1%溶液在10分钟内即可使足丝溶解,胎贝脱落。 相似文献
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利用简并引物PCR以及cDNA末端快速扩增(rapid amplification of cDNA ends,RACE)技术获得了总长度为1197bp的翡翠贻贝Perna viridis CYP4基因cDNA序列.根据所获得的翡翠贻贝cDNA序列设计定量PCR引物,利用实时荧光定量PCR(Real-time quantitative PCR)技术测定了CYP4基因在野生翡翠贻贝消化腺、足和性腺中的表达水平.此外,本研究还应用实时荧光定量PCR技术对经过Aroclor1254暴露处理对翡翠贻贝性腺中CYP4表达水平的影响进行了定量测定.研究结果表明,CYP4基因在野生翡翠贻贝消化腺、足和性腺中均有表达,且其表达水平具有组织差异和性别差异;Aroclor1254暴露处理对翡翠贻贝性腺CYP4基因的表达水平有明显的诱导作用,并且这种诱导作用有明显的时间和剂量效应.本研究为CYP4基因作为生物大分子标记物在环境监测领域的应用提供了分子生物学水平的支持. 相似文献
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^125I在翡翠贻贝体内积累与分布 总被引：1，自引：1，他引：1
研究了翡贻贝Ｐｅｒｎａ ｖｉｒｉｄｉｓ的个体大小对放射性核素＾１２５Ｉ在其体内的积累与分布。实验结果表明，小个体对＾１２５Ｉ的浓集能力比大个体强。在贝体各部分组织中，足丝对＾１２５Ｉ浓缩因子比贝体其余部分高得多，为软体组织的３０－２００倍，足的２００－６００倍，贝壳的６００－１０００倍。足丝的重量虽不及整体湿重的１％，但积累的＾１２５Ｉ占贝体＾１２５Ｉ总重量的５０％－７５％；足丝的浓集因子与贻贝整 相似文献
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Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
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. 相似文献
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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。 相似文献
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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. 相似文献
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Derek V. Ellis 《Marine Georesources & Geotechnology》2001,19(1):51-63
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. 相似文献
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G. Parthiban 《Marine Georesources & Geotechnology》2000,18(3):223-235
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. 相似文献
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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. 相似文献
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Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引：1，自引：0，他引：1
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. 相似文献
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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. 相似文献