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1.
异源精子诱导牙鲆雌核发育二倍体 总被引：13，自引：0，他引：13
采用紫外线照射处理的石鲽精子和受精后冷休克的方法诱导了牙鲆雌核发育。结果表明:用2只平行的相距15cm的20W紫外灯管,照射距离为10cm,在5~100s时间范围内照射石鲽精子时,受精卵的发育表现了典型的哈特维希效应,照射40s的精子所得胚胎的孵化率达到最高峰(41%),染色体观察结果显示,此照射剂量组的所有胚胎均为单倍体(n=24),表明照射精子遗传失活的有效性和可靠性。如果冷休克处理前受精卵保持在(15.5±0.5)℃,受精卵在一定的休克温度(0~10℃)条件下,用不同休克起始时间(受精后1~10min)及冷休克处理持续时间(15~90min)均能诱导染色体加倍。对冷休克处理条件的优化结果表明,在2~4℃条件下,受精后3min开始、冷休克处理45min时,二倍体诱导率最高,达79.7%。染色体鉴定显示,处理组的正常胚胎均为二倍体(2n=48),未发现单倍体和非整倍体。 相似文献
2.
黄姑鱼雌核发育的人工诱导及鉴定 总被引：1，自引：0，他引：1
采用紫外线（UV）灭活的同源精子通过冷休克抑制第二极体排放诱导黄姑鱼的雌核发育。黄姑鱼精子最适的灭活剂量为420 mJ/cm2,紫外照射剂量与黄姑鱼精子和卵子授精后的受精率及孵化率之间表现出明显的Hertwig效应。多次试验筛选的黄姑鱼雌核发育的最适条件为授精后2min在3℃处理8min。雌核发育仔鱼经形态学和流式细胞仪鉴定为二倍体。进一步利用10对微卫星分析了遗传物质在亲本和子代中的传递情况,结果表明雌核发育后代的等位基因完全来自于母本,没有父本基因参与;雌核发育后代在5个位点微卫星位点具有较高的重组率,使其与母本保持了高度同质性。 相似文献
3.
采用紫外线(UV)灭活的同源精子通过冷休克抑制第二极体排放诱导黄姑鱼(Nibea albiflora)的雌核发育。结果表明,黄姑鱼精子最适的灭活剂量为420mJ/cm2,紫外照射剂量与黄姑鱼精子和卵子授精后的受精率及孵化率之间表现出明显的Hertwig效应。多次试验筛选的黄姑鱼雌核发育的最适条件为授精后2min于3℃处理8min。雌核发育仔鱼经形态学和流式细胞仪鉴定为二倍体。进一步利用10对微卫星分析了遗传物质在亲本和子代中的传递情况,结果表明雌核发育后代的等位基因完全来自于母本,没有父本基因参与;雌核发育后代在5个微卫星位点具有较高的重组率,使其与母本保持了高度同质性。 相似文献
4.
紫外线照射使精子遗传物质失活,用细胞松弛素B(CB)处理受精卵抑制第二极体释放,诱导刺参(Apostichopusjaponicus)雌核发育二倍体。用强度为2561μW/(cm2.s)的紫外线(254 nm)照射不同时间的精子与正常卵子受精。结果发现随照射时间的增加,卵裂率、早期胚胎存活率和小耳幼虫发生率逐渐降低,照射30 s时小耳幼虫发生率降为0。受精后35 min,显微镜下观察到有20%~30%受精卵排出第1极体时,用浓度0.5μg/mL的CB持续处理受精卵20 min,诱导出刺参第二极体抑制型雌核发育二倍体,雌核发育二倍体发育速度低于正常二倍体。微卫星分析表明,雌核发育二倍体诱导成功率为93.3%。 相似文献
5.
平鲷(Rhabolosargus sarba)养殖群体具有雌性生长优势的特点.应用冷休克方法进行平鲷雌核发育二倍体人工诱导,采用高温消毒的自然海水为精子稀释液,精液经强度为700μW/(cm2·s)的紫外线(UV)照射100 s,染色体遗传物质失活,卵子经激活后,可以获得95%～100%单倍体胚胎.实验结果表明:在卵子激活后5 min进行冷休克,温度0～8℃,处理时间持续15min,雌核发育二倍体的受精率达71.3%～82.7%,孵化率为24.7%～36.3%,2～6℃为适宜冷休克温度,此范围内的温度对雌核发育二倍体的受精率和孵化率没有显著影响(P>0.05),而与0,1和8℃实验组的受精率和孵化率差异均显著(P<0.05);在冷休克温度为3℃、持续时间为15 min的条件下,初始冷休克时间在4～6 min之间的受精率和孵化率均较高,分别达到60.0%～67.1%和30.6%～36.5%,其组间受精率和孵化率没有显著差异(P>0.05),而与其他实验组的孵化率存在显著差异(P<0.05);冷休克持续时间以11～19 min为宜,受精率和孵化率分别为46.9%～65.8%和31.7%～42.4%,在此时间内,冷休克持续时间对平鲷的雌核发育二倍体受精率和孵化率影响不显著(P>0.05).选用冷休克温度、初始冷休克时间和持续时间分别为3℃,5和15 min作为平鲷雌核发育二倍体的诱导条件是显著有效的. 相似文献
6.
以紫外灭活的同源(大黄鱼)精子和未灭活的异源(鮸鱼)精子为激活源, 采用冷休克处理的方法诱导了大黄鱼雌核发育二倍体, 进行胚胎发育和 SSR 标记分析的比较研究。结果表明, 异源组的受精率和孵化率高于同源组, 但存活率低于同源组; 两组中经冷休克处理未能恢复倍性的胚胎发育畸形而陆续死亡, 恢复倍性的胚胎在发育程序上均与普通大黄鱼相同, 但各阶段出现时间较对照组滞后; SSR 分析显示同源组子代中有 16.7%出现父本条带, 异源组子代均未出现父本条带。以灭活的同源(大黄鱼)精子和未经灭活的 相似文献
7.
采用紫外线照射的方式使精子遗传物质失活,通过细胞松弛素B(CB)的处理来抑制受精卵第二极体的释放,人工诱导紫贻贝(Mytilus gallopovincialis)雌核发育二倍体。将精子在强度为2561μW/(cm~2·s)的紫外线(254 nm)下进行时间梯度的照射,之后与正常的卵子受精,实验发现随照射时间的增加,卵裂率、早期胚胎存活率和D形幼虫发生率总体呈下降趋势,在照射55 s时D形幼虫发生率降为0。受精后25 min,用浓度0.5μg/mL的细胞松弛素B(CB)持续处理受精卵20 min,诱导出紫贻贝第二极体抑制型雌核发育二倍体。通过微卫星分析鉴定所得的子代个体均为雌核发育二倍体。 相似文献
8.
条石鲷(Oplegnathus fasciatus)是我国重要的经济鱼类,具有复性染色体性别决定型(X1X1X2X2/X1X2Y)。利用紫外线(UV)灭活的同源精子通过冷休克方法诱导了条石鲷的雌核发育,筛选精子紫外灭活剂量并优化冷休克相关参数。结果表明:条石鲷精子最适的灭活剂量为80 mJ/cm2雌核发育的最适条件为授精后2 min在3～4°C水温下处理10 min。条石鲷雌核发育子代经形态学和流式细胞仪鉴定为二倍体,进一步利用微卫星分析表明雌核发育后代的等位基因完全来自于母本没有父本基因参与。对子代的性比和生长进行了比较,结果表明条石鲷雌核发育后代均为雌性,15月龄后雌核发育后代比普通条石鲷具有更快的生长速度。研究结果为条石鲷单性苗种的培育及其性别决定机制的深入研究提供基础。 相似文献
9.
人工诱导雌核发育牙Ping的染色体及核型证明 总被引：4，自引：1，他引：3
于１９９４￣１９９６年,分别在威海海洋渔业捕捞公司（石岛）和鸿洋实业总公司龙须岛育苗场采集人工培育的３－５龄牙Ｐｉｎｇ亲鱼,采用紫外线照射法使牙Ｐｉｎｇ精子遗传物质失活,并用冷休克法抑制受精卵第二极体释放,从而获得雌核发育二倍体牙Ｐｉｎｇ。原肠期采用空气干燥法、Ｇｉｅｍｓａ染色,得到雌核发育二倍体,正常二倍体及单倍体的染色体制片,进行染色体和核型的分析。结果表明,牙Ｐｉｎｇ的雌核发育二倍体和正常二 相似文献
10.
人工诱导雌核发育牙鲆的染色体及核型证明 总被引：6，自引：1，他引：5
于1994-1996年,分别在威海海洋渔业捕捞公司（石岛）和鸿洋实业总公司龙须岛育苗场采集人工培育的3－5龄牙鲆亲鱼,采用紫外线照射法使牙鲆精子遗传物质失活,并用冷休克法抑制受精卵第二极体释放,从而获得雌核发育二倍体牙好。原肠期采用空气干燥法、Giemsa染色,得到雌核发育二倍体、正常二倍体及单倍体的染色体制片,进行染色体和核型的分析。结果表明,牙鲆的雌核发育二倍体和正常二倍体的染色体数均为2n=48,核型为48t,即48条端部着色点染色体,臂数NF=48,两者的核型设有明显差异;单倍体为24条端部着丝点染色体;在3个组别中,第一号染色体上都有一明显的次缢痕。雌核发育二倍体牙鲆的诱导率为98％。 相似文献
11.
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
12.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
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
13.
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
14.
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
15.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
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
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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
18.
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. 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