凡纳滨对虾的遗传育种研究现状

凡纳滨对虾(Litopenaeus vannamei Boone),由于其生长快,抗环境变化能力强,对饵料的要求低,肉味鲜美、出肉率高,成为世界上公认的优良养殖对虾品种之一.凡纳滨对虾自1998年从美国夏威夷再次引进到中国华南,并相继突破集约化防病养殖和全人工繁育技术以来[1],已成为中国海水养殖动物中发展最快的一个种类,其养殖产量已达到中国养殖对虾产量的80%～90%.然而目前中国凡纳滨对虾亲虾多数直接从虾塘挑选,造成品质参差不齐,抗病力下降,生产周期延长,严重制约了中国凡纳滨对虾养殖业持续健康发展.凡纳滨对虾亟需形成稳定优良的养殖品系.     

循环水养殖系统在凡纳滨对虾种虾养殖中的应用效果初探

循环水养殖系统在凡纳滨对虾种虾养殖中应用较少,本研究应用循环水养殖系统养殖凡纳滨对虾种虾,设定4个不同的养殖密度(30、40、50、65尾/m2),初始体重:(0.102±0.008)g,研究凡纳滨对虾种虾在循环水养殖系统中的生长情况。养殖期间定时对对虾体重和水体指标(氨氮、亚硝酸氮、pH、水温、微生物)进行分析测定。通过对各项数据分析表明:低密度组(30、40、50尾/m2)凡纳滨对虾体重增长较快,各组特定生长率分别为(3.83±0.03)%、(3.87±0.01)%、(3.81±0.03)%,绝对增重率分别为(0.201±0.009)、(0.214±0.004)、(0.194±0.009)g/d,但均无显著性差异(P0.05);高密度组(65尾/m2)的凡纳滨对虾体重增长较慢,特定生长率和绝对增重率分别为(3.41±0.02)%和(0.107±0.004)g/d,该结果与低密度组间存在显著性差异(P0.05)。低密度组中凡纳滨对虾养殖水体的水质指标要优于高密度组,4个密度组中氨氮、亚硝酸氮、绿菌均维持在安全浓度范围内,仅仅黄菌数量略高。综合分析,采用该养殖系统养殖凡纳滨对虾的最优密度为50尾/m2。因此,本研究可为循环水养殖系统养殖凡纳滨对虾种虾提供参考。     

二溴海因和碳水化合物水平对凡纳滨对虾生长和免疫的影响

研究了低盐度条件下,二溴海因和碳水化合物水平对凡纳滨对虾(Litopenaeus vannamei)生长和免疫的影响,共3个实验。实验1研究了二溴海因对凡纳滨对虾存活的影响,发现在0.2、5和20三个盐度水平,随着二溴海因浓度的升高,凡纳滨对虾存活率呈下降趋势;二溴海因对凡纳滨对虾的安全浓度随盐度的增加呈上升趋势。实验2和实验3研究了盐度、二溴海因浓度和饲料中碳水化合物水平对凡纳滨对虾生长和免疫的影响,结果表明:在低盐度养殖条件下,凡纳滨对虾长期生活于二溴海因环境中,可导致对虾处于应激状态,需要消耗体内较多的免疫因子,血清酚氧化酶和超氧化物歧化酶活性降低,生长速度下降,而在饲料中适量增加碳水化合物不仅可促进对虾生长又可起到饲料蛋白质节约作用。     

两种围栏养殖模式防白斑综合征病毒(WSSV)效果的比较

2003年在乳山养殖场采用两种围栏养殖模式养殖了凡纳滨对虾,并对其防白斑综合征病毒(WSSV)效果进行了比较。结果表明,凡纳滨对虾在养殖过程中WSSV阳性率有下降趋势,浮游动物WSSV阳性率较低,布围隔的防病毒效果好于网围隔。     

集约式养殖凡纳滨对虾体长与体重的关系

研究了集约化养殖凡纳滨对虾Litopenaeus vannamei体长与体重的关系,通过全过程采样测试并经回归分析得到不同生长阶段的体长、体重关系式。研究发现当体长大于12．5cm时相同体长的雌虾要明显重于雄虾（p〈0．01）。比较地膜养殖池与沙底养殖池对凡纳滨对虾生长的影响,结果表明当养殖天数大于90d时,地膜养殖池对虾的生长明显优于沙底养殖池对虾（p〈0.05）。     

凡纳滨对虾遗传多样性研究中AFLP体系的建立

凡纳滨对虾是当今世界公认的重要对虾养殖品种之一,然而良种选育研究仍相对落后,亟需采用分子遗传学手段加以解决.本文以凡纳滨对虾为材料,对预扩增体系、选择性扩增体系中的稀释倍数、dNTP浓度、Taq浓度、Mg2+浓度、引物浓度进行比较,结果表明,300 ng基因组DNA采用5U PstI和5UMseI双酶切4 h,16℃连接过夜,连接产物稀释10倍进行预扩增,预扩增产物稀释50倍进行选择性扩增,能够得到稳定丰富的条带,最终建立了适用于凡纳滨对虾的AFLP反应体系.本研究又进一步应用优化后的AFLP反应体系,从64对选择性扩增引物组合中筛选出12对多态性高的引物组合,便于对凡纳滨对虾基因多态性位点进行分析,从而为凡纳滨对虾的遗传多样性研究奠定基础.     

三种凡纳滨对虾池塘养殖模式环境因子变化和养殖效益的分析

研究了3种凡纳滨对虾池塘养殖模式环境因子变化情况和对养殖效益的分析。实验分为3种不同的养殖模式:对虾单养组、鱼虾混养A组、鱼虾混养B组。结果表明:pH变化范围在8.40~9.06之间,其中对虾单养组pH较之两组鱼虾混养组略高,最高值达9.06;COD变化范围在101~211之间,其中对虾单养组COD较之两组鱼虾混养组略高,范围在132~211之间;氨氮和亚硝酸盐氮浓度为对虾单养组>鱼虾混养A组>鱼虾混养B组;异养菌数目和弧菌数目,随着养殖的进行呈现逐渐增加的趋势,最大值分别为对虾单养组1.1×106 CFU/mL、2.0×103 CFU/mL,鱼虾混养A组1.45×106 CFU/mL、1.80×103 CFU/mL,鱼虾混养B组1.20×106 CFU/mL、1.56×103 CFU/mL;养殖效益上,总产值、纯利润、亩利润、投入产出比均呈现出鱼虾混养B组>鱼虾混养A组>对虾单养组。由此可见,凡纳滨对虾和鱼类混养,可以在保证水质的前提下,提高凡纳滨对虾养殖规格,提高投入产出比,增加养殖效益,是一种相较于凡纳滨对虾单独养殖优越的养殖模式;而不同规格和数量的鱼类和不同数量凡纳滨对虾的混养,又会产生不同的养殖效益。     

凡纳滨对虾EST-SSR标记的筛选及遗传多态性检测

为了研究我国海南地区某凡纳滨对虾(Litopenaeus vannamei)繁育群体的种质资源多样性,选取14个比利时野生对虾的EST微卫星标记,以240个中国人工选育的凡纳滨对虾个体为研究对象,检测这些标记在该养殖群体遗传多样性评估中的可行性,结果表明,有7个引物可扩增出清晰条带,其中5个引物(CNM-MG 345,...     

高位池养殖对虾携带白斑综合症病毒变化

采用实时荧光定量 PCR 技术研究6口高位池塘斑节对虾和凡纳滨对虾携带WSSV变化,结果表明:养殖过程中凡纳滨对虾WSSV携带量最高为9.7×105拷贝/g;斑节对虾最高携带量为9.5×105拷贝/g.凡纳滨对虾WSSV感染率分别为:苗种没有携带WSSV;30d为80.0%;60 d为90.O%;90 d为90.0%;120 d为93.3%,斑节对虾潜伏感染率分别为:苗种没有携带WSSV;30d为73.3%;60d为83.3%;90d为90.O%:120d为96.7%.     

植物乳杆菌对凡纳滨对虾致病菌抑制及其对肠道菌群结构的影响

本研究以凡纳滨对虾(Litopenaeus vannamei)为对象,通过琼脂扩散法、荧光染色法与分光光度法筛选出对凡纳滨对虾致病菌有抑制作用、对对虾肠黏液有黏附作用且对盐度有耐受性的3株菌(YRL45、KTP(C-2)、QL),经16S rDNA测序比对发现此3株菌均为植物乳杆菌。将其混合饲喂凡纳滨对虾4周,通过高通量测序研究虾肠道菌群变化。研究表明,混合植物乳杆菌的饲喂对凡纳滨对虾肠道菌群的α多样性无显著性影响,变形菌门和拟杆菌门为凡纳滨对虾肠道优势菌门,植物乳杆菌对凡纳滨对虾肠道中放线菌门的丰度有一定的提高。通过LEfSe分析,发现植物乳杆菌处理组中潜在致病菌发光杆菌属减少,而属于光合细菌的赤杆菌属有所增加。研究结果为益生菌在凡纳滨对虾的应用提供了一定的理论指导。     

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.     

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.     

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.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Evaluation of the Risk of Marine Slope Instability: A Pseudo-3D Approach for Application to Large Areas

This article presents a methodology developed to evaluate the instability of submarine slopes that extend over a large area. Special attention was paid to (1) the complex geometry (bathymetry) and the expanse of the slope, (2) the heterogeneity of the sediment, and (3) the distribution of the pore pressure. The safety factor was considered as a spatially varying quantity. The General Formulation (GLE, Fredlund and Krahn 1977), which fully satisfies equilibrium conditions, was used for evaluating the stability of the marine slope. The submarine slope failure, which occurred on 16 October 1979 during the construction of the new Nice airport, was studied in order to test the developed model. Geotechnical parameters were taken from experimental tests carried out by IFREMER on 19 cores extracted at different depths (from 27 m to 1300 m) (Cochonat, Bourillet, and Savoye, 1993; Mulder et al., 1994). Many scenarios were proposed in order to explain the cause of the Nice slope failure (Habib, 1994). In this article, two of those scenarios were tested. Simulation results are presented and discussed.