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1.
曼氏无针乌贼血细胞形态观察及吞噬性能的研究   总被引:1,自引:0,他引:1  
用组织学和免疫学方法对曼氏无针乌贼(Sepiella maindroni)的血细胞进行形态观察和免疫活性研究。根据血细胞大小和美兰染色结果,将曼氏无针乌贼的血细胞分为2类:较小的血细胞圆形,直径7.65~8.28μm,细胞核卵圆形,核质比约0.66,约占细胞总数的45.3%;较大的血细胞圆形,直径9.58~10.42μm,细胞核肾形,核质比约0.40,有些细胞具双核,约占细胞总数的54.7%。饥饿乌贼血细胞数量较正常乌贼有明显下降(t-检验,P<0.05),较大血细胞的比例有所上升,可达70%。细菌吞噬试验结果表明,较小血细胞对细菌无吞噬能力,而较大血细胞具有较强的细菌吞噬能力。饥饿组曼氏无针乌贼血细胞吞噬活力稍低,但并无显著差别(t-检验,P>0.05)。对曼氏无针乌贼血细胞形态和功能的研究,为探索曼氏无针乌贼免疫防御机理提供了基础资料。  相似文献   

2.
采用活体解剖和组织切片技术对曼氏无针乌贼精荚器结构及精荚形成过程进行了初步研究。结果表明,曼氏无针乌贼精荚器由输精管、粘液腺、放射导管腺、中被膜腺、外被膜腺、硬腺、终腺等腺体组成,依靠结缔组织相连,并外披被膜形成椭圆形囊状结构;精子经输精管输送到粘液腺内,形成精子团;在放射导管腺内,精荚的放射导管结构和外膜、中膜、内膜...  相似文献   

3.
我国海域耳鲍(Haliotis asinisne)精子发生的超微结构研究   总被引:1,自引:1,他引:0  
应用透射电子显微镜技术研究了我国海域耳鲍精子发生的全过程。结果表明,耳鲍精原细胞呈近椭圆形,染色质分布较均匀,线粒体较少;初级精母细胞较大,染色质凝聚成小块状,线粒体增多;次级精母细胞较初级精母细胞小,线粒体较多,部分线粒体发生融合,呈扁囊状。分化早期精细胞染色质凝聚成团块状,多数贴附于核膜内面,胞质中出现前顶体颗粒。分化中期精细胞染色质继续凝聚成较大的团块,线粒体在核的一端融合,形成数量少、体积大的线粒体,前顶体颗粒形成圆形外膜明显的前顶体。分化后期精核由近圆形变成长桶状,核内染色质凝聚并均质化,前顶体泡化发育成顶体,鞭毛形成,精细胞分化成精子。成熟精子为鞭毛型精子,由头部、中段和尾部(鞭毛)3部分组成。  相似文献   

4.
青蛤精细胞分化的超微结构研究   总被引:32,自引:0,他引:32  
曾志南  李复雪 《海洋学报》1991,13(4):547-551
本文在超微结构水平上研究青蛤Cyclina sinensis精子发生中的精细胞演变过程和精子的结构.结果表明,在精细胞分化过程中,细胞核形态由椭圆形变化为圆柱形,核染色质形态演变经历:由细颗粒聚结成的小团块→直径为20-41nm的颗粒物(含部分团块状)→直径为36.8-52.6nm的粗颗粒→高电子密度的匀质物.由高尔基复合体分泌的前顶体颗粒聚合发育为大的球形颗粒,并逐渐移至核前端,参与精子顶体的形成.线粒体出现融合,有少部分线粒体解体.融合结果,线粒体数量由多变少,体积由小变大,最后5个线粒体于核后端形成一线粒体环,并与近、远侧中心粒组成精子中段的主要结构.青蛤精子属原生型,由头部、中段和尾部组成.此外,我们观察到青蛤精子亚顶体区有一特殊的球状结构.  相似文献   

5.
采用透射电镜技术,研究了3种鲈形目鱼类褐菖鲉Sebastiscus marmoratus、黑鲷Sparus macrocephalus及平鲷Rhabdosargus sarba(Forskal)精子发生早期精原细胞、初级精母细胞及次级精母细胞的超显微结构变化。结果表明,3种鱼生精细胞形态结构及代谢活动变化主要体现在核的变化、线粒体数目与结构的变化及高尔基体和溶酶体的行为变化。3种鱼核的变化基本一致:细胞核由近圆形或椭圆形转变为多角形;核质逐渐浓缩;核仁从明显结构至完全消失。褐菖鲉精原细胞时期线粒体分布较多,并出现拟染色质与线粒体相粘附;而平鲷与黑鲷精原细胞时期的线粒体分布较少,无拟染色质。3种鱼高尔基体与溶酶体的变化也有相似性。黑鲷的初级精母细胞中还观察到典型的环层状的髓样小体的结构。  相似文献   

6.
长竹蛏精子发生和精子的超微结构观察   总被引:1,自引:0,他引:1  
利用透射电镜观察长竹蛏Solen strictus精子发生和精子的超微结构,揭示了从精原细胞发育为精子过程中超微结构的变化。其过程主要包括:生精细胞体积逐级减小,细胞核由椭圆形转变为圆形,染色质以颗粒状形式浓缩,内质网和高尔基体分泌的前顶体颗粒融合形成前顶体囊、前顶体囊最终形成顶体,线粒体逐渐融合与发达,以及中心体移动及鞭毛形成。精细胞的分化可分为4个时期。成熟精子属原生型,全长约38—43μm,由头部、中段和尾部3部分组成。头部顶体较短,约为核径的五分之一,呈倒置的碗状,轴向纵切面为马鞍形,顶体物质为分布均匀的高电子密度物质;亚顶体腔几乎伸达顶体的顶端,内含均匀的较低电子密度物质。细胞核呈圆球形,无核前窝,但有一浅的核后窝。中段由4—5个椭圆形线粒体和2个相互垂直的中心粒组成。尾部为典型的“9 2”型结构。  相似文献   

7.
采用常规生物学方法和统计回归分析方法,对浙江近海曼氏无针乌贼的繁殖生物学特性进行了研究,比较了不同时期浙江近海曼氏无针乌贼卵巢成熟系数(GSI)、生物学体型及个体生殖力与生物学指标关系。结果表明,浙江近海曼氏无针乌贼GSI在4月份达到最高(9.51%±7.23%),相比20世纪60年代初、80年代初,自然海域曼氏无针乌贼的性腺发育提前,且生殖期延长。20世纪80年代初曼氏无针乌贼的生物学体型、怀卵量及个体生殖力均大于60年代初和自然海域曼氏无针乌贼,同时曼氏无针乌贼在人工养殖条件下生物学体型、怀卵量及个体生殖力增大。浙江近海曼氏无针乌贼的个体生殖力均随着胴长(ML)、体质量(W)、卵巢质量(WO)、GSI这些指标的增大而增大,除体质量相对生殖力(FW)与ML为密切正相关外,个体生殖力与这些指标的关系均达到了极显著水平(P<0.01)。多元线性逐步回归分析表明,WO是影响浙江近海曼氏无针乌贼个体生殖力的最重要指标。  相似文献   

8.
太平洋牡蛎精子形成的研究   总被引:1,自引:0,他引:1  
透射电镜下研究了太平洋牡蛎 (Crassostrea gigas Thunberg)的精子形成过程。精子细胞中含有前顶体颗粒、线粒体、高尔基体、中心粒等多种细胞结构 ,线粒体、前顶体颗粒的数量较多。在精子形成过程中 ,前顶体颗粒逐渐汇集、愈合成顶体泡 ,顶体泡覆盖在细胞核的一端逐渐发育为顶体 ;线粒体则向顶体相反的方向移动 ,最后移到核后端形成 4个较大的线粒体球 ;中心粒移到核后端由远端中心粒形成轴丝 ;细胞核发生致密 ,形态发生变化 ,最后形成杯状的精子核 ;多余的细胞质被抛弃。  相似文献   

9.
沟纹巴非蛤精子发生过程的超微结构观察   总被引:5,自引:0,他引:5  
利用透射电镜观察沟纹巴非蛤(Paphia exarataPhilippi)精子的发生和精子的超微结构,揭示了从精原细胞逐渐发育成精子过程中超微结构的变化。其过程主要包括核逐步拉长、染色质浓缩、顶体形成、线粒体逐渐融合、胞质减少以及中心粒演变为轴丝等。精细胞的分化可分为五个时期。成熟精子属原生型,由头部、中段和尾部三部分组成。头部顶体呈圆锥状,其中的顶体物质分布不均匀,基部密度较其他区域高;亚顶体腔呈倒V字型,内含均匀的低密度物质。细胞核卵圆形。中段由4~5个椭圆形线粒体和2个相互垂直的中心粒组成。尾部为典型的“9 2”型结构。  相似文献   

10.
采用常规生物学方法和统计回归分析,研究了养殖曼氏无针乌贼卵巢成熟系数(GSI)的变化规律和个体生殖力与其主要形态指标之间的相互关系.结果表明,曼氏无针乌贼春苗100日龄时GS/达到最高(12.2%±3.25%),秋苗140日龄时GSI达到最高(13.7%±3.69%).曼氏无针乌贼秋苗的体质量相对生殖力(F<,W>)极...  相似文献   

11.
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   

12.
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   

13.
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.  相似文献   

14.
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   

15.
16.
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.  相似文献   

17.
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   

18.
19.
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   

20.
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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