北极海洋沉积物中可培养细菌及其多样性分析

利用Zobell 2216E培养基和涂布平板法对北极海洋沉积物中可培养细菌进行分离纯化,并利用16SrRNA基因进行分子鉴定与系统发育分析。根据菌落形态学特征,从59个站点的沉积物样品中共分离纯化获得570株细菌;基于16SrRNA基因的分子鉴定与系统发育分析表明,分离到的可培养细菌分别属于细菌域的4个门,5个纲,12个目,23个科,47个属,102个种,其中γ-Proteobactria占绝大多数;有14株菌株与模式菌株的16SrRNA基因序列相似性小于97%,为6个潜在的新种。北极海域的海洋沉积物中存在着丰富的微生物种质资源,为开发新型生物活性物质和特殊功能基因打下了基础。     

印度-太平洋石鲈亚科鱼类DNA条形码及分子系统进化研究

为探讨DNA条形码基因COⅠ序列在石鲈亚科鱼类物种鉴定的有效性,本研究分析了印度-太平洋区域的石鲈亚科7个属29种鱼类9个个体长度为651 bp的COⅠ基因序列,利用MEGA 5.0计算石鲈亚科种内与种间的遗传距离,并基于最大简约法与最大似然法构建了其分子系统进化关系。结果显示:石鲈亚科鱼类种间遗传距离在0.021—0.240之间,平均遗传距离0.184;种内遗传距离在0.000—0.009之间,平均0.004。其中种间平均遗传距离(0.184)显著大于种内平均遗传距离(0.004),种间遗传距离是种内的46倍。同时,各物种间遗传距离均大于Hebert推荐区分物种的最小种间遗传距离0.02(2%)。基于COⅠ序列构建的系统进化树,同一物种不同个体间均能聚成独立的单系,表明COⅠ基因可作为石鲈亚科物种准确鉴定的有效条形码基因。同时,系统进化树上,石鲈属是非单系类群,主要形成5个分支,而不同分支的种类与其地理分布存在一定的相关性,与近年部分分子系统地理学的研究观点一致。     

水产品鲐鱼(Pneumatophorus japonicus)细菌多样性及优势微生物分析

为研究鲐鱼(Pneumatophorus japonicus)在不同冻藏时期的优势微生物,并且得到一个较全面的细菌群落组成结构,采用16SrDNA基因克隆文库及克隆子分析等方法,分别对冻藏1d、8d和20d条件下鲐鱼鳃体系中的细菌种群多样性、优势微生物及其中产组胺菌的变化进行分析。结果表明,不同时期鲐鱼鳃内的细菌多样性均较强;冻藏1天的鳃体系中不动杆菌属(Acinetobacter)占优势为总数的77.5%,产组胺细菌如泛菌属(Pantoea)和肠杆菌属(Enterobacter)较少;第8天优势细菌种群是梭杆菌属(Fusobacteria bacterium)和希瓦氏菌属(Shewanella),而产组胺菌如发光杆菌属(Photobacterium)和弧菌属(Vibrio)较前期数量有所增加;冻藏到第20天的优势种群为哈夫尼菌属(Hafnia)和沙雷菌属(Serratia),它们均是产组胺的菌群。鲐鱼中细菌多样性及其优势微生物的变化等全面信息可为了解鲐鱼水产品组胺发生的微生物机制及其控制方法提供重要依据。     

基于DNA条形码研究中国枪乌贼和鸢乌贼的食物种类组成*

中国枪乌贼(Uroteuthis chinensis)和鸢乌贼(Sthenoteuthis oualaniensis)作为中国南海头足类的关键种, 对海洋生态系统的物质流动与能量循环具有重要影响, 其摄食生态的研究将对海洋食物网的构建具有重要意义。由于传统胃含物分析法难以准确鉴定糜状饵料生物的组成, 本研究利用DNA条码技术, 针对中国枪乌贼和鸢乌贼不可辨认的食物糜提取组织DNA, 选用线粒体基因细胞色素C氧化酶亚基I(Mitochondrial cytochrome oxidase subunit I, COI)作为分子标记, 获得的序列在Genbank中进行比对分析, 并使用GMYC(Generalized Mixed Yule Coalescent)模型进行物种界定和构建系统进化关系。结果成功鉴定出中国枪乌贼饵料物种有13种, 鸢乌贼饵料物种有8种, 共20种(其中1种为共有饵料)。比较发现, 汕头-台湾浅滩渔场的中国枪乌贼主要摄食鱼类、甲壳类和头足类, 而南海中部海域鸢乌贼则主要摄食鱼类和头足类。两物种均存在同类相食现象, 但鸢乌贼表现更明显。     

Evolution in Littorina: ecology matters

Organisms of marine rocky shores are exposed to physical stress from abiotic factors, such as temperature, salinity and wave action. These factors vary over compressed temporal and spatial scales, producing an exceedingly heterogeneous habitat with steep gradients of selection, and it seems likely that this has a strong influence on the evolution of populations of rocky shore organisms. With the periwinkles (genus Littorina) as a model group, I review strategies for coping with small-scale heterogeneous environments and what implications these strategies have on the evolution of these species.Some species of Littorina have long-lived pelagic larvae and sites of various habitats are thus recruited from a common gene pool. This largely prevents local adaptation but minor adjustments are possible through a plastic phenotype. Other species of the genus are directly developing with no larval dispersal and among these there is evidence of strong local adaptation forming distinct ecotypes in contrasting habitats by parallel evolution. In at least one of the directly developing species (L. saxatilis) divergent selection among ecotypes has resulted in partial reproductive barriers that further impede gene flow among ecotypes. Furthermore, convergent evolution among species has produced superficially similar morphs in different habitats. Ecotype formation, ecological reproductive barriers and convergence among species all indicate that ecological processes are critical for evolution of Littorina species.     

基于16S rDNA和看家基因序列分析技术的鲍鱼养殖水体弧菌种类的鉴定

采用TCBS选择性培养基从厦门某鲍鱼养殖场的养殖水体中分离到19株细菌.经16S rDNA序列分析,所有菌株均属于弧菌属（Vibrio）,且与最近似的弧菌模式种的同源性都在98.99%以上.由于弧菌种间16S rDNA序列相似度极高,无法仅靠16S rDNA序列比对来鉴定这些菌株到种的水平.16S rDNA序列的系统发育分析也显示,大多数菌株与弧菌模式种无法归为一簇,表明16S rDNA基因在弧菌种的分类鉴定上分辨率不高.进一步采用基于4种看家基因（rpo A、pyr H、gap A和top A）的多位点序列分析技术（MLSA）对分离到的弧菌菌株进行分类鉴定,结果显示19株海洋弧菌归于溶藻弧菌（Vibrio alginalyticus）与魔鬼弧菌（Vibrio diabolicus）2个种,表明这两种弧菌是该鲍鱼养殖场水体环境中的优势弧菌种,在鲍鱼养殖弧菌病害防治方面需要重点关注.此外,看家基因与16S rDNA基因的多态性分析表明,4种看家基因的多态位点比率均高于16S rDNA.4种看家基因串联后的多态位点比率高达41.1%,远高于16S r DNA基因的13.4%,表明看家基因相较于16S rDNA基因有着更高的分辨率,更适合于海洋弧菌的分类鉴定.     

Dietary analysis of harbour seals (Phoca vitulina) from faecal samples and overlap with fisheries in Erimo,Japan

The number of harbour seals in Japan has been rebounding since protection began in the mid‐1980s. With the increase in seal numbers, increased conflict with fisheries has occurred through depredation and the belief that seals compete with fisheries for prey. However, competition can only be determined if the prey species and quantities seals consume over time are known. We studied the diet of harbour seals in Erimo, site of the largest population of harbour seals in Japan, from 2011 to 2012 and assessed the degree of prey overlap with local fisheries. We used both hard parts and DNA techniques to identify prey items in seal scats, and compared these results to local fisheries data. A total of 46 prey occurrences was detected by both methods, of which 17 matched between techniques at least to the family level. Hard parts methods identified five incidences of prey undetected by DNA methods in five scats (one incidence per scat). DNA methods identified 24 additional prey occurrences in 13 scats, for which no hard part evidence for that prey had been found. This more than doubled the total number of prey occurrences across the 15 scats compared. Overall, the most frequently occurring harbour seal prey were walleye pollock (Theragra chalcogramma), sculpins and snailfishes. In contrast, the top three groups targeted by fisheries were codfishes, salmon and invertebrates. Many species common in the harbour seal's diet such as snailfishes and blennies were not targeted by fisheries. Fishes such as greenlings, sculpins, rockfishes and Japanese anchovy (Engraulis japonicus) were common in the diet of harbour seals, but made up a very small proportion of fisheries catches in Erimo. The importance of other prey species varied between seasons. Sculpins, greenlings and forage fishes were the top three prey groups for harbour seals in spring by percent modified frequency of occurrence, whereas the most important target groups by percentage mass caught by fisheries were codfishes, cephalopods and other invertebrates. Sculpins and rockfishes remained as important prey items for harbour seals in summer and autumn, in addition to codfishes, snailfishes and blennies. In contrast, the main groups caught by fisheries in summer were other fishes, particularly Japanese amberjack (Seriola quinqueradiata) and various species of sharks and eels, and invertebrates. By autumn, Erimo fisheries had focussed on catching salmon. Salmon were taken by harbour seals as well during this period, but at a relatively lower frequency compared to other prey groups. The results of our study show that although harbour seals consumed several of the prey species targeted by fisheries, the relative importance of these species to seals and fisheries and the seasons in which they were targeted were different.     

Discard management: A spatial multi-criteria approach

Discard management needs to draw on scientific research and advice, usually supported by specific statistical modeling analysis. A wide range of statistical analysis methods were applied to fishery data in an attempt to distinguish factors that influence the species discard composition. While such approaches are important, they are still incomplete for disaggregating the economic and spatial-temporal factors for analyzing of this process and obtain a whole view of this issue. Our study aims to fill this gap by identifying, describing, and quantifying factors that influence discards of trawl fisheries using a multivariate approach based on five complementary aspects: “economic”, “vessel characteristics”, “spatial”, “temporal” and “environmental”. In addition, a spatial multi-criteria approach were used to investigate discard hot-spot areas using ecological criteria such as vulnerability and resilience of the discarded species. Using these ecological criteria will concentrate conservation efforts on the most relevant sites minimizing discards of a variety of potentially vulnerable species. This approach was applied to a case study of a multi-species demersal bottom trawl fisheries in north Spain, Cantabrian Sea (ICES area VIIIc). Results showed how spatial and economic factors highly affect species discard composition, identifying specific spatial-temporal discard hot-spots to be preferentially avoided by fishers. Mitigation measures for future fisheries management strategies should be implemented at multiple stages of the discarding process, both in the selection of the fishing grounds and the economic valorization of the discarded species.     

Feeding habits of amphipods (Crustacea: Malacostraca) from shallow soft bottom communities: Comparison between marine caves and open habitats

Marine caves are environments of great interest since the organisms that inhabit them are forced to develop specific adaptations to high constraint conditions. Because of some of these particular conditions, such as light absence or oligotrophy, it can be expected that feeding strategies into caves differ from that present outside them. Nevertheless, no studies have been done to compare the trophic structure of marine caves and open habitats, at least for amphipod communities, considering their importance both inside and outside of the caves. In this study, the diet of the dominant amphipod species living on shallow sediments, both inside and outside of six marine caves in western Mediterranean, was characterized. Thereby, the gut content of 17 amphipod species was studied, being this study the first attempt to establish the feeding habit of most of these species. Analysis of digestive contents of the species showed that amphipod diet is less diverse in sediments than in other environments, such as algae and seagrasses. No herbivorous species were found in the sediment and carnivorous amphipods showed a little variety of prey, feeding mainly on crustaceans. Differences in the trophic structure were also found between marine caves and open habitats sediments: while outside the caves detritivorous was the dominant group (both in number of species and number of individuals), amphipods mainly play the role of carnivorous inside the caves. No detritivorous species were found into the caves, where carnivorous represents almost 60% of amphipods species and more than 80% of amphipod individuals. This pattern obtained in amphipods differ from the general trend observed in marine cave organisms, for which a generalist diet, such as omnivory, usually is an advantage in these oligotrophic conditions. The possible causes of this pattern are discussed.     

泰国近海习见有毒立方水母和钵水母的遗传分析

本研究利用线粒体16S rDNA和核基因18S rDNA片段,对泰国沿海常见的有毒水母进行遗传分析,并比较了2个基因片段作为通用分子标记,在研究水母类多个纲的遗传多样性中的应用。研究发现,泰国近海的有毒水母存在较高的遗传多样性,所获得的32个样品可以分为9个种,包括4种钵水母、4种立方水母和1种水螅水母。然而,完全确定各种的分类地位,还需要更多的形态、生活史等方面信息。两个基因片段均能明确区分各种类,但核基因18S序列比线粒体基因片段更为保守。根据16S基因片段序列计算水母种内和种间的K2P(Kimura 2-parameter)遗传距离,发现所研究的9个水母种类,种内遗传距离在0~0.050之间,其中94%的种内遗传距离小于0.040,同纲种间的遗传距离为0.204~0.474,其中91%的种间遗传距离大于0.250;而利用18S基因,种内距离在0~0.002之间,同纲种间距离为0.008~0.066(平均为0.038,SE=0.006)。16S的AT碱基含量明显高于核基因18S,且16S的碱基含量在不同纲之间有显著差异,进一步表明水母线粒体16S基因的突变率相对较高,适合研究水母较低分类阶元以及种下的遗传差异。     

印度洋深海沉积物样品纯培养细菌的分离鉴定

为探索印度洋深海沉积物中纯培养细菌的多样性,本文对采自印度洋12个沉积物样品进行细菌纯培养分离,共获得343株细菌.所有细菌采用16S?rRNA基因进行比对分析,鉴定为4个门:厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)、放线菌门(Actinobacteria)和拟杆菌门(Bacteroi...     

东海区底拖网渔业主要经济鱼类渔业生物学的初步研究

根据1997~2000年东海区底拖网渔业资源调查资料,分析了18种主要经济鱼类的渔业生物学特征,运用体长频率法估算了von Bertalanffy生长参数、总死亡系数、自然死亡系数、捕捞死亡系数和开发率。结果表明,大部分鱼类已出现个体小型化,15种鱼类的开发率过高,处于超额开发状态,其中,4种为重度超额开发,开发率大于0.8,7种为中度超额开发,开发率介于0.7~0.8之间,4种为轻度超额开发,开发率为0.5~0.7。建议加强保护和管理,以利于鱼类资源的可持续利用。     

中心硅藻梅尼小环藻淡水株和海水株亚显微结构的形态学差异

本文利用18S r RNA基因对4株经形态学初步鉴定的梅尼小环藻(Cyclotella meneghiniana)进行了分子鉴定。结果显示,这4株分离自淡水环境(2株)和海水环境(2株)的梅尼小环藻的18S r RNA基因序列基本一致,并与已经报道的梅尼小环藻(登录号为GQ148712和AY496212)聚为一支,不同方法所构建的系统树的支持率分别为99%(邻接法)和98%(最大似然法),表明这4株来自不同环境的藻为同一物种——梅尼小环藻。随后作者利用扫描电镜技术在亚显微水平上对这4株梅尼小环藻进行了观察,结果显示:梅尼小环藻淡水株和海水株具有相当不同的亚显微结构特征。生活在海水的梅尼小环藻藻株具有更大的细胞以及更多的中央支持突。此外,本文还对造成梅尼小环藻种内高水平形态差异的原因以及18S r RNA基因序列是否可以作为小环藻属物种鉴定的分子标记做了分析和讨论。     

基于16S rRNA 部分序列探讨部分鳚亚目鱼类的分子系统进化关系

通过PCR扩增获得了3科5属6种中国黄渤海海域的鳚亚目(Blennioidei)鱼类的线粒体16S rRNA基因序列片段约669bp碱基,结合来自 GenBank的5种鳚亚目其他科鱼类的相应基因片段,并以眼斑雪冰鱼(Chionodraco rastrospinosus)为外群,生成供系统发育分析的序列矩阵,利用MEGA 4.0软件分析序列的碱基组成、差异百分比、转换/颠换值等,应用最大简约法(MP)和邻接法(NJ)构建系统发育树.结果显示:在鳚亚目鱼类的16S rRNA 片段生成的序列矩阵中发现有碱基的插入缺失现象,共有207 bp变异位点,转换/颠换值为0.8,碱基平均差异为3.36;支持绵鳚(Enchelyopus elongates)归于鳚亚目绵鳚科(Zoarcidae),鳚(Azuma emmnion)归于鳚亚目线鳚科(Stichaeidae);方氏云鳚(Enedrias fangi)和云鳚(Enedrias nebulosus)种间遗传距离只有0.01,亲缘关系最近.     

Regulation of Tilapia metallothionein gene expression by heavy metal ions

Tilapia is a common fish species inhabiting inland waters and estuarine regions in Hong Kong and Southeast Asia, and useful for bio-monitoring of metal pollution. Metallothionein (MT) gene expression in fish tissues has been useful to sub-lethal risk assessment as biomarker of exposure to metal ions in fishes inhabiting metal contaminated area. To investigate metal inductions of Tilapia MT gene expression in vivo, Tilapias were injected with different concentrations of heavy metals and tissues were then removed for quantitative PCR assay using mimic PCR methods. All of the metal ions tested (Cu(2+), Cd(2+), Hg(2+), Ni(2+), Pb(2+) and Zn(2+)) were able to induce hepatic MT mRNA levels. Renal MT mRNA levels of Cd(2+) and Zn(2+) treated fish was not induced with significant fold induction, however MT mRNA levels in gills were sensitive to the administrations of these metal ions. These data indicated that Tilapia MT mRNA levels in gills and liver are sensitive biomarker of exposure to various metal ions.     

A new analytical approach to the characterisation of macro-epibenthic habitats: linking species to the environment

A challenge for marine ecologists is to explain distinct and recurrent patterns in the distribution of marine faunas by developing new methods that identify and link environmental processes responsible for these patterns. Methods that describe and predict the distribution of benthic faunas using single factors such as sediment type or water depth are generally inadequate, particularly when applied on a broad scale. When a combination of factors such as near-bed tidal velocity, surface seawater temperature and salinity are evaluated in conjunction with sediment type and depth, however, they more clearly characterise benthic habitats. Using principal component analysis (PCA) patterns in the distribution and abundance of different echinoderm and crustacean species were shown to be predictable and characterised by a suite of physical factors. Characterising benthic habitats using factors from the environment provided a potential mechanism for predicting patterns in their spatial distribution. A new analytical method for characterising a species habitat was constructed using a combination of PCA and a generalised additive model. The method is able to predict the habitat preferences of individual species based on their association with physical factors characterising their habitat. These preferences were then used to describe the probability of a species occurring across a range of different habitats, which is referred to as the habitat-envelope. This method enables one species habitat range to be compared directly to another. The strong correlation between species patchiness and its habitat-envelope was used to develop an index to identify species that are potentially more sensitive to habitat change. Distinct patterns in the habitat preferences of echinoderms were generally stronger than those identified for crustaceans. Thus, crustaceans were found more likely to exploit a wider range of habitats than echinoderms, suggesting that they may be less sensitive to habitat change.     

温度和盐度对短节硬毛藻(Chaetomorpha brachygona Harvey)生长发育的影响研究

利用双因素实验和单藻培养等方法,对采自广东南澳岛的短节硬毛藻(Chaetomorpha brachygona Harvey)进行研究,在不同温度和盐度条件下,对该硬毛藻的生长、活力以及形态进行了观察与测定。结果表明,温度和盐度对短节硬毛藻的生长均有一定影响,当温度为20°C时,藻体培养第3、6和12天活力分别为0.70—0.75Y、0.60—0.70Y和0.55—0.65Y,培养12天时藻体有生殖细胞形成,此温度有利于藻体维持活力;温度为25—30°C时,培养第3天时会大量形成生殖细胞;在盐度10、20、40和50时,藻体的生长与温度相关,即30°C25°C20°C;在盐度20—30时,藻体长度最大达4.55 cm;在盐度10—30时,更有利于藻体生长,整体趋势为2030104050。因此,实验条件下,温度25—30°C、盐度10—30更利于短节硬毛藻的生长和形成生殖细胞。本实验表明,短节硬毛藻为暖水、广盐性种,有可能在我国南方海区大量生长并扩散,具有引发绿潮的潜力。     

Estimation of size at first maturity in two South African coral species

The corals Acropora austera and Platygyra daedalea have been the subject of extensive reproductive and population genetic studies in the iSimangaliso Wetland Park (iSimangaliso), on the KwaZulu-Natal coast, eastern South Africa. Despite this, estimates of size at first maturity in these two species are lacking. This information could be used to provide a baseline to differentiate juveniles from adult sizes of corals, an important factor for assessing the condition of scleractinian communities in reefs. Here, we present the methods followed to provide such estimates for these two hard corals. Using generalised linear models and assuming knife-edge maturity (50% probability), it was estimated that A. austera from iSimangaliso matures at c. 15 cm mean colony diameter (MCD) (95% CI: 9.25–20.75 cm MCD) and P. daedalea matures at c. 7 cm MCD (95% CI: 4.55–8.39 cm MCD). These estimates were comparable to those for tropical species which is remarkable considering the high-latitude nature of the sampled reefs. It is expected that the findings from this study will assist in the assessment of reproduction, recruitment, survival and genetic variation in clonal organisms such as corals, and will provide a baseline to assess the effects of climate change on coral communities in the region.