条纹斑竹鲨消化系统的初步研究

对条纹斑竹鲨(Chiloscyllium plagiosum)的消化器官进行解剖和组织学观察。结果表明,条纹斑竹鲨消化道较短,其长度仅为鱼体全长的49.31%±2.60%。牙细小,三齿头型,多行在使用,每侧有12~14纵行。食道粗短,具有6~8条粗大的纵褶。胃呈"V"型,可分为贲门部和幽门部。小肠可分为十二指肠和回肠,回肠具有18片几乎平行的螺旋瓣。大肠可分为结肠和直肠,均较短。肝脏大,分为左右两叶,左叶较长而宽大,胆囊位于肝左叶近中央背侧,肝脏质量占鱼体质量的4.92%±1.22%。胰脏可分背、腹两叶,胰脏质量占鱼体质量的0.16%±0.04%。条纹斑竹鲨消化系统的组织学特征与其它鱼类基本相似,但大肠上皮为复层扁平上皮,其中含有大量大型粘液细胞。研究表明,条纹斑竹鲨的消化系统具有软骨鱼纲板鳃亚纲的消化系统的基本结构特征,同时又具有自身所特有的与其生活习性相适应的形态结构特征。本研究为条纹斑竹鲨的人工配合饲料的研制和投饵技术提供基础资料。     

基于线粒体DNA细胞色素b序列分析3个条纹斑竹鲨群体的遗传结构和遗传分化

测定和分析了广东、福建、海南3个不同地理群体共71尾条纹斑竹鲨Chiloscyllium plagiosum的线粒体细胞色素b(mtDNA cyt b)全序列.结果表明,条纹斑竹鲨cyt b基因全长1146bp,具15个单倍型.较低的核苷酸多样性(π=0.00254)及单倍型多样性(h = 0.7195)提示条纹斑竹鲨线粒体DNA的进化速率较慢.各群体内的Tajima's D检验的结果均不显著(P>0.10),表明各群体进化过程中未出现扩张和持续增长,群体大小维持稳定.NJ树和单倍型网络图结果表明较早出现的是广东群体,福建群体较晚出现.通过计算其遗传距离值、估算其基因流(Nm) 及进行AMOVA 分析,均显示福建群体与海南和广东群体的分化最远,而海南及广东群体间分化不明显.研究表明距离隔离是条纹斑竹鲨福建、广东和海南群体遗传分化的重要因素.     

条纹斑竹鲨肌肉的营养成分

对条纹斑竹鲨肌肉营养成分进行分析 ,结果表明 :条纹斑竹鲨肌肉的粗蛋白含量为21.7% (干基为70.8% ) ;蛋白质营养价高 ,第一限制氨基酸为色氨酸 ,氨基酸价为88 ;无机质含量丰富 ,特别是Mg,Fe,Zn ,Se等微量元素 ,尤其是Se含量达1.44×10-6 (干基为6.89×10-6) ,是含Se很高的水产品     

我国南部海域条纹斑竹鲨线粒体DNA控制区遗传多态性研究

摘要:在对我国南部沿海闽东、闽南、粤西、海南、北部湾5个海域的条纹斑竹鲨群体线粒体控制区多态性研究中,获得长度为1 094~1 096 bp的线粒体控制区完整序列。序列比对发现了6个多态性核苷酸位点,定义了8个单倍型。5个群体的单倍型多样度(h=0.542 5~0.744 8)和核苷酸多样度(π=0.000 571~0.000 980)均处于较低水平,说明条纹斑竹鲨的线粒体DNA进化速率较低。分子方差分析(AMOVA)结果显示群体间的遗传差异较小(Fst=0.216 26,P<0.000 1),变异主要发生在群体内部。10 000步Markov链计算的群体间遗传分化概率及单倍型系统地理学分析结果将5个群体分成两个地理种群(台湾海峡种群、南海北部种群)。综合分析表明条纹斑竹鲨的基因流主要在浅海近岸水域扩散,遗传变异程度受地理结构和距离隔离影响。     

哈维氏弧菌对条纹斑竹鲨4种酶活性的影响

以哈维氏弧菌（Vibrio harveyi）对条纹斑竹鲨（Chiloscyllium plagiosum）进行病原接种试验,分别在4、8、12、24、48、72、96h后测定肝脏、脾脏、鳃及血清的酸性磷酸酶（acid phosphatase,ACP）、碱性磷酸酶（alkaline phosphatase,AKP）、超氧化物歧化酶（superoxide dismutase,SOD）和血清中溶菌酶（lysozyme,LSZ）的活力.实验结果表明：对照组条纹斑竹鲨的这4种酶的活力呈现出明显的组织差异性,血清中SOD活力为124.32 U/cm3,显著高于其他3种酶的活力;其他组织中3种酶的活力由高到低依次为SOD、ACP、AKP.在实验组条纹斑竹鲨被感染4～72h期间,血清中SOD活力明显下降,ACP活力持续下降,感染96h后除LSZ外,其他3种酶的活力都呈回升趋势;其他组织中ACP与AKP活力变化均为被感染4h后下降,12h后明显回升,SOD则在被感染4h后活力上升,而后下降,96h后回升.这4种酶的活力的变化主要是应激作用与非特异性免疫防御作用共同作用导致的结果.     

条纹斑竹鲨线粒体控制区和细胞色素b基因序列分析

对厦门和湛江海域的条纹斑竹鲨Chiloscyllium plagiosum（Bennett，1830）]的线粒体DNA控制区和细胞色素6（Cytb）基因进行PCR扩增和测序，获得线粒体DNA控制区、Cytb基因和tRNA^Pro。基因全序列（GenBank序列号：EU363740～EU363752）。结果表明，tRNA^Pro。基因长度为69bp，控制区长度为1094～1096bp，Cytb基因全序列长度为1146bp。tRNA^Pro。基因非常保守，未发现碱基变异。所测30个个体中，控制区只有4个多态位点，5种不同的单倍型；Cytb基因全序列共有10个多态性位点，7种单倍型。Cytb基因的1146个碱基编码381个氨基酸，氨基酸链共有3个变异位点，4种单倍型，厦门群体具有4种单倍型，湛江群体只有1种单倍型。综合Cytb基因和控制区序列，2个条纹斑竹鲨群体共有10种单倍型，其中厦门群体有9种单倍型，湛江群体仅4种单倍型。研究结果表明条纹斑竹鲨在控制区和Cytb基因序列上的遗传多样性均较低，厦门群体的遗传多样性水平高于湛江群体。     

条纹斑竹鲨5个地理群体的简单重复序列中间区域分析

简单重复序列中间区域(inter-simple sequence repeat,ISSR)是一种微卫星类分子标记。为明确条纹斑竹鲨(Chiloscyllium plagiosum)中国群体的遗传多样性和遗传关系,作者利用ISSR技术对福建厦门(XM)、福建平潭(PT)、广东湛江(ZJ)、海南海口(HK)和台湾(TW)5个土著地理群体的条纹斑竹鲨进行了遗传多样性和遗传关系分析。从56对ISSR引物中筛选出13对多态性引物,扩增共获得81个重复性的位点,其中多态性位点57个,多态位点百分率为70.37%。5个群体的多态位点百分率、Nei’s基因多样性和Shannon’s信息指数分别为38.27%~58.02%,0.1353~0.2155和0.2032~0.3193。UPGMA聚类分析表明PT群体首先和XM群体聚类,再与TW群体聚类,最后与ZJ群体和HK群体形成的分支聚类,即形成了与地理距离远近相关的基因交流模式。     

黑鲷（Sparus macrocephalus）成熟精,卵和精子入卵早期过程的初步观察

黑鲷精子入卵早期发育迅速。精、卵相遇的3－5sec左右,卵孔管出现一种能引诱精子入卵的物质;精卵相触约10－15sec左右,即精子进入卵孔管后,管内又涌出另一种能阻止多余精子继续入卵的物质;同时,受精锥形成。约15-54sec左右,受精膜发生;约90sec左右受精膜举起,围卵腔雏成;约180sec左右受精锥开始退缩,精子头部和颈部被俘入卵内;约300sec左右出现第二极体。文中对卵孔管出现的这两种物质进行了浅析。     

软骨鱼类输卵管腺研究进展

输卵管腺(oviductgland)是软骨鱼类特有的生殖器官,由雌性软骨鱼类的输卵管前段发育形成,输卵管腺对于软骨鱼类的生殖具有重要意义,参与了卵壳的合成,卵胶的分泌,精子储存等多个重要生命过程。同时输卵管腺的合成产物中含有一种高度交联的胶原蛋白复合材料,具有韧性强、抑菌、抗污、可降解等特点,是极具开发价值的海洋生物材料。但是目前中国该领域研究基础较为薄弱,本文通过对软骨鱼类的生殖方式、输卵管腺的结构、卵壳分泌过程等几部分的研究进展进行阐述,以期为软骨鱼类的繁育、新型生物材料的开发提供启发。     

泥螺生殖系统的组织学研究

随机选取不同发育阶段的泥螺 ,活体解剖 ,取出其生殖系统 ,切成若干小段 ,按常规组织学方法制成切片 ,光学显微镜观察并拍照 ,对其生殖系统的组织学进行研究。结果表明 ,泥螺生殖系统由生殖器本部 ,交媾器和卵精沟三部分组成。生殖器本部包括两性腺、两性管、精囊、蛋白腺、粘液腺、缠卵腺、交媾囊、摄护腺。卵巢位于两性腺周围 ,精巢位于中间 ,并先熟先形成精子。生殖细胞成熟后经由单层上皮细胞组织的两性管排出 ,两性管末端的交媾囊为精卵受精的部位。交媾囊一侧的蛋白腺、粘液腺分别分泌蛋白质及粘液包围卵。交媾器包括刺激器与阴茎两部分 ,两者均由多层肌肉细胞组成。外卵精沟由皮肤凹陷而成 ,沟壁具纤毛。     

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.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.     

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.     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.     

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.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics.