海南万宁小海近岸表层海水弧菌组成及其变化

于2006年冬至2007年秋分四个季度对海南万宁小海近岸表层海水的弧菌种类分布及数量变化进行了调查.共分离到27种弧菌属细菌,其中副溶血弧菌、创伤弧菌、溶藻弧菌、霍乱弧菌、河流弧菌和拟态弧菌6种弧菌为主要弧菌.在6种主要弧菌中,溶藻弧菌、副溶血弧菌和霍乱弧菌在夏季和秋季检出率较高;河流弧菌在春季和夏季的检出率较高;拟态...     

EST-derived microsatellites in Pseudosciaena crocea and their applicability to related species

Simple sequence repeat (SSR) markers were obtained for the large yellow croaker Pseudosciaena crocea using 1 205 expressed sequences tags (ESTs) from the NCBI database. Primers for 48 ESTSSR loci were designed and screened with 30 P.crocea specimens captured from Guanjingyang sea area in Fujian Province of China. Sixteen of the loci were polymorphic, which were amplified with 3 to 11 alleles per locus and the mean of 6.13. The observed and expected heterozygosity per locus ranged from 0.091 to 0.844 (mean 0.544) and from 0.118 to 0.892 (mean 0.644), respectively. Polymorphic information content (PIC) ranged from 0.115 to 0.866 (mean 0.593). The results for cross-species amplification of the 16 large yellow croaker EST-SSRs on P. polyactis, C. niveatus, C. lucidus, A. argentatus and J. belengeri revealed that 14, 12, 11, 7 and 6 loci were successfully amplified with 1 to 10 alleles with an average of 4.5 per locus, respectively, which are suitable for population genetics studies of these species and useful for phylogenetic relationship analysis among these species. Overall, this study provides a set of type I markers for population genetics studies and genome mapping for large yellow croaker and its closely related species.     

Nonculturability of the pathogenic Vibrio parahaemolyticus in live culture of Grateloupia turuturu is associated with bacterial attachment to the algal thalli

The invasive red alga Grateloupia turuturu Yamada could turn Vibrio parahaemolyticus into nonculturable state in live algal culture. In order to elucidate the mechanism of such an effect, a series of culture experiments were performed in this investigation based on three hypothesized causes, namely bacterial attachment, production of reactive oxygen species (ROS) and the discharge of water soluble secondary metabolic compounds. The results reveal that attachment to the thallus surface of G. turuturu was the major reason for the decrease of V. parahaemolyticus in seawater. Further investigations show that V. parahaemolyticus attachment to the surface of algal thallus in live cultures of seaweeds was a common phenomenon. However, the disappearance of the culturability of V. parahaemolyticus occurred only on the thallus of G. turuturu over 72 h among all six algal species tested. Electron microscopic scanning shows that most of V. parahaemolyticus attached to G. turuturu changed from the initial normal bacilli to coccoid-shape after 72 h. The enclosure experiments by enclosing the algal thallus in tubes demonstrate that the nonculturability of V. parahaemolyticus in the water of live culture of G. turuturu occurred after the physical contact of the V. parahaemolyticus to the alga. The capacity of G. turuturu in affecting the culturability of V. parahaemolyticus was not influenced after inhibition of photosynthesis by treatment of 3''-(3,4-dichlorophenyl)-1'',1''-dimethyl urea (DCMU) at non-lethal levels. Production of reactive oxygen species after addition of live culture of bacteria was excluded by on-line analyzing the oxidation of dichlorohydrofluorescein (DCFH) to dichlorofluorescein (DCF) in the presence of peroxidase on a VersaFluor fluorometer.     

Genetic and morphological description of Eucalanus spinifer T. Scott, 1894 (Calanoida: Eucalanidae), a circumglobal sister species of the copepod E. hyalinus s.s. (Claus, 1866)

A distinct genetic form of the eucalanid calanoid copepod Eucalanus hyalinus s.l. was identified in subtropical and temperate waters of the Pacific, Atlantic, and Indian Oceans. Results from mitochondrial (16S rRNA, COI) and nuclear (ITS2) genetic markers suggest that the two E. hyalinus forms are reproductively isolated. Eucalanus spinifer T. Scott is taken out of synonymy with E. hyalinus and is applied to the smaller of the two genetic forms, increasing the number of species in the genus Eucalanus to a total of six. Adult females of the sister species E. hyalinus s.s. and E. spinifer can be distinguished morphologically by the shape of the anterior portion of the head in lateral and ventral views, asymmetry in the length of antennule segments 22 and 23, length ratios of 22/5 and 23/5 of the longer of the antennules, the length of the caudal rami, and total body size, as measured by total length or prosome length. We illustrate and describe both adult females and males of E. spinifer, and discuss aspects of sexual dimorphism. The sister species are sympatric throughout much of their circumglobal biogeographic distributions, but appear to have centers of abundance in slightly different water mass types.     

Distribution of amphipods Ischyrocerus on the red king crab, Paralithodes camtschaticus: Possible interactions with the host in the Barents Sea

The determination of costs and benefits experienced by crustaceans as a result of occupation by their symbionts has received increased attention from marine ecologists. However, the interactions between some important species and their associates remain unclear. We examined the distribution of amphipods in the genus Ischyrocerus on the red king crab Paralithodes camtschaticus, a commercially important species, in two areas of the Barents Sea. Ischyrocerus commensalis was found on 30.5% of crabs in Dalnezelenetskaya Bay (DZB) with the mean number per crab being 55.1, in Dolgaya Bay (DLB) these rates were 28.6% with 19.3 specimens per crab. Sympatric species Ischyrocerus anguipes was found on 13.5% of crabs in DZB with a mean of 7.3 individuals per host, in DLB it had much lower occurrence (1.3% and 1.5 specimens per host). There were no significant differences between proportions of male and female crabs infested by amphipods in both areas examined. Prevalence of amphipods was similar among years examined except for I. commensalis on small crabs (carapace length CL <90 mm) and I. anguipes on large crabs (CL >90 mm) in DZB. We found that I. commensalis and I. anguipes are not egg predators of P. camtschaticus in the Barents Sea, at least in summer. High numbers of I. commensalis occur in crab gills, and both mean intensity of the amphipods and their empty tubes increased with crab size. In the gills, I. commensalis predominated in the section nearest the mouth parts. Possible negative impacts for the hosts due to gills infestation are discussed. In contrast, I. anguipes were predominately found on the carapace and limbs of crabs and appears to be a less specific symbiont of P. camtschaticus. Both amphipod species seem to be commensals, however possible negative impacts for the host could not be excluded.     

南海浮游被囊动物火体虫科(Pyrosomatidae)——新记录种的形态特征

火体虫科(Pyrosomatidae),隶属于脊索动物门、尾索动物亚门、海樽纲、磷海樽目,全球海域已报道8种。本文描述了采自南海火体虫科一新记录种短轮火体虫 (Pyrosomella verticillata) 群体和单体的形态特征,分析了其群体长度、宽度与轮数的关系,并比较了该种与已在南海发现的大西洋火体虫(Pyrosoma atlanticum)的形态差异。研究标本保存在南海海洋生物标本馆。     

一株分离自胶州湾的裸甲藻形态相似种的分子系统学研究

对一株分离自胶州湾的裸甲藻形态相似种(Gymnodinium sp.ZX)进行了分子水平的分类鉴定.提取基因组DNA后扩增核糖体小亚基和转录间隔区序列,经纯化、克隆并测序.将获得的序列分别进行Blastn同源性分析,并下载相关序列构建系统进化树,结果表明,该藻与共生藻(Symbiodinium)亲缘关系较近,而与裸甲藻...     

Fatty acids dynamics during embryonic development in genus Uca (Brachyura: Ocypodidae), from the mangroves of Inhaca Island,Mozambique

Variations in egg volume and fatty acid (FA) content through embryogenesis were evaluated in Uca species from Inhaca island, Mozambique. Egg volume increased 96.1%, 93.3%, 84.2%, 92.9%, 96.3%, respectively, in Uca annulipes, Uca inversa, Uca urvillei, Uca chlorophthalmus and Uca vocans (p < 0.05). Fatty acid content decreased through embryogenesis, showing its importance as fuel during embryonic development. Major fatty acids were 16:0, 18:0, 16:1n-7, 18:1n-9, 18:1n-7, 18:2n-6, 20:5n-3 and 20:4n-3. Unsaturated fatty acids (UFA) and saturated fatty acids (SFA) were used up at a similar rate for U. annulipes and U. inversa contrarily to the other three species. Within the UFA, MUFA were more consumed than PUFA for all species except U. chlorophthalmus. The high values detected for fatty acid trophic markers (essential C₁₈ and C₂₀ PUFAs) and odd-numbered fatty acid suggest that Uca species occupy medium trophic level, primarily omnivores and scavengers/detritivores consuming algae common in the intertidal habitats. The fatty acid consumption pattern during embryonic development was essentially similar between species with some variation as expected, as FA content varies within species mainly due to female feeding ecology, nutritional and physiological conditions, differential demands on resource allocation and geographic and seasonal variations in embryonic development.     

Ecological performance and possible origin of a ubiquitous but under-studied gastropod

Invasions by non-indigenous species (NIS) have been suggested to alter local, regional and global biota on unprecedented scales. To manage NIS, it is pivotal to identify whether a species is introduced or native, but even today the geographical origin of thousands of species worldwide remain uncertain. Most of these ‘cryptogenic species’ are inconspicuous and rare, but in a few instances, they can also be abundant and conspicuous species, with large impacts on community structure. The identification of cryptogenic species, and summarizing information on their most likely origin, is an important task in invasion biology, and can highlight the need for research and management. Here, we document that the gastropod Batillaria australis in the Swan River estuary (Perth, Western Australia) is a conspicuous species of uncertain origin. A literature review combined with new survey data revealed that all evidence point to a recent human-mediated transfer; for example, it is absent from the fossil record, was first collected in 1954, has a low parasite diversity, has increased its population size dramatically in recent times, is separated by >3000 km from conspecifics, has no long-distance dispersal mechanisms, and existing ocean currents run against a natural range extension. Surprisingly, despite political and scientific focus on NIS hardly any ecological data have been published on this species from Western Australia. We show that B. australis is highly abundant in both seagrass beds (424 ± 29 ind m⁻²) and on unvegetated sand flats (92 ± 22 ind m⁻²) being orders of magnitudes more abundant than any native gastropod in the Swan River. Experiments showed that high resistance to predation and environmental stress potentially explains its success. From our survey data, we calculated that >3.6 billion invasive snails today occupy the Swan River. This large snail populations support other organisms; for example, almost 1 billion macroalgae are found attached to living B. australis and >100 million hermit crabs occupy its empty shells. Given Battilaria’s high abundance, wide distribution, large size, persistent shells that support other organisms and bioturbating behavior, it seems inescapable that this potential invader has impacted the ecosystem functioning of the Swan River. We argue that the search for abundant species of uncertain origin should continue, and that these species generally should be treated with the same interest as high status invaders to mitigate impacts in already invaded systems and to avoid secondary spread into neighboring ecosystems.     

Stage-V copepodites of Calanus sinicus and Calanus jashnovi (Copepoda: Calanoida) in mesopelagic zone of Sagami Bay as identified with genetic markers, with special reference to their vertical distribution

We applied genetic makers to identify Calanus species occurring in Sagami Bay, Japan, in order to investigate their vertical distribution in the upper 1000 m. First, interspecific genetic distances of three gene loci, mitochondrial small ribosomal RNA (srRNA), nuclear internal transcribed spacers 1 (ITS1) and 2 (ITS2), were estimated from morphologically distinguishable adult females of Calanus sinicus, Calanus jashnovi and Calanus pacificus that were collected from Sagami Bay, the Kuroshio Extension and the Oyashio region, respectively. The highest levels of interspecific genetic distance were observed in srRNA, followed by ITS1 and ITS2. The intraspecific genetic distances within C. sinicus were much lower than the interspecific genetic distances, indicating that DNA sequences in these loci are consistent with the morphological differences. This information was used as a criterion for species identification based on DNA sequence variation, and allowed us to identify the fifth copepodites (CVs) or younger stages of these species. Next, the vertical distribution of Calanus species was investigated in Sagami Bay in May 2006, on the basis of a stratified sampling in the upper 1000 m. By applying the genetic markers, 23 individuals comprising all copepodite stages were allocated into either C. sinicus or C. jashnovi, and the small- and large-sized CVs were identified as C. sinicus and C. jashnovi, respectively. The total abundance of C. sinicus was highest at 0-50 m and decreased with depth. On the contrary, CV individuals of C. sinicus were abundant not only in 0-50 m but also below 200 m with minimum occurrences in 150-200 m depth. C. jashnovi was much less abundant than C. sinicus and comprised of only CIV and CV which occurred in the upper 100 m and deeper than 50 m depths, respectively. The abundance of C. sinicus in the 1000-m water column of Sagami Bay was at a level comparable to that in shelf waters, suggesting the importance of off-shelf individuals in the biological production and organic transport in the respective areas.     

Juvenile bottlenecks and salinity shape grey mullet assemblages in Mediterranean estuaries

Previous research has suggested that competitive bottlenecks may exist for the Mediterranean grey mullets (Osteichthyes, Mugilidae) at the fry stage with the exotic Cyprinus carpio (Osteichthyes, Cyprinidae) playing a central role. As a consequence, the structure of grey mullet assemblages at later stages is thought to reflect previous competition as well as differences in osmoregulatory skills. This paper tests that hypothesis by examining four predictions about the relative abundance of five grey mullet species in 42 Western Mediterranean estuary sites from three areas (Aiguamolls de l'Empordà, Ebro Delta and Minorca) differing in the salinity level and occurrence of C. carpio. Field data confirmed the predictions as: (1) Liza aurata and Mugil cephalus were scarce everywhere and never dominated the assemblage; (2) Liza saliens dominated the assemblage where the salinity level was higher than 13; (3) Liza ramado always dominated the assemblage where the salinity level was lower than 13 and C. carpio was present; and (4) Chelon labrosus dominated the assemblage only where the salinity level was lower than 13 and C. carpio was absent. The catch per unit effort of C. labrosus of any size was smaller in the presence of C. carpio than where it had not been introduced, which is in agreement with the juvenile competitive bottleneck hypothesis. Discriminant analysis confirmed that the assemblage structure was linked to the salinity level and the occurrence of C. carpio for both early juveniles and late juveniles as well as adults. The data reported here reveal that the structure of grey mullet assemblages inhabiting Mediterranean estuaries is determined by salinity and competitive interactions at the fry stage.     

一种新的海洋微藻病毒丝氨酸蛋白酶基因的克隆表达及其活性分析

从海洋球石藻Emiliania huxleyi病毒EhV99B1的基因组中克隆了丝氨酸蛋白酶(Sp)基因(GenBank登录号:KC161207),对该基因的开放阅读框(ORF)进行系统的生物信息学分析,并在大肠杆菌中融合表达,通过亲和层析法获得了纯化的重组Sp。结果表明:EhV99B1-Sp基因的ORF为1 110bp,编码368个氨基酸,蛋白相对分子质量为39.5kDa;该基因片段与GenBank中EhV86-Sp的同源性很高,核苷酸及其对应的氨基酸序列同源性分别为95%和97%,而与其他物种Sp序列的同源性仅为28%~32%,说明其可能是丝氨酸蛋白酶家族中的一个新成员;预测的二级结构特征显示EhV99B1-Sp的蛋白结构域中具有典型的LTAGHC(组氨酸活性位点区域)和AICNGDSGGPLF(丝氨酸活性位点区域)两个丝氨酸蛋白酶催化活性位点的氨基酸基序,是一个两次跨膜蛋白;将该基因在大肠杆菌中进行低温诱导表达,得到分子量为60kDa的重组蛋白,经鲤鱼肌肉丝氨酸蛋白酶(MBSP)抗体检测证实为Sp,且重组蛋白在大肠杆菌细胞中具有明显的生物学活性。本研究结果为进一步探讨EhV99B1-Sp在病毒与宿主相互作用过程中的调节作用及其功能与应用奠定基础。     

Diopatra neapolitana and Diopatra marocensis from the Portuguese coast: Morphological and genetic comparison

This paper reports the presence of Diopatra marocensis in European waters, for which Diopatra neapolitana was the only species recognized until recently. Both species coexist in transitional waters, where D. marocensis may be mistaken for young specimens of D. neapolitana. The population of D. marocensis studied in the coastal shelf can be traced back to 1997 and is increasing in density, apparently benefiting from a local anthropogenic organic enrichment source.     

Feeding preferences of estuarine mysids Neomysis integer and Rhopalophthalmus tartessicus in a temperate estuary (Guadalquivir Estuary,SW Spain)

Mysid shrimps are an important component of estuarine food webs because they play a key role in energy transfer as intermediate prey. We investigated the seasonal, tidal and depth specific variation in the diet of the estuarine mysids Neomysis integer and Rhopalophthalmus tartessicus and explored its implications for the planktonic community structure of a temperate estuary (Guadalquivir Estuary, SW Spain). Neomysis integer is an opportunistic omnivore feeding mainly on mesozooplankton and on members of the detrital–microbial loop, shifting prey seasonally according to availability. In contrast, R. tartessicus showed a more carnivorous diet and shifted its target prey during seasons of low resource availability. Despite statistically significant differences in diet composition, both species shared prey of similar size, particularly juvenile Mesopodopsis slabberi, the most abundant mysid species in this estuary, and copepods. Although these similarities imply inter-specific resource competition, their co-existence is achieved by niche partitioning and spatial segregation: the higher osmoregulatory capacity and foraging plasticity of N. integer confers a broader niche breadth for this species allowing N. integer to inhabit the more stressful oligohaline region of the estuary where R. tartessicus cannot survive. We propose that this mechanism relaxes the potential for competition between N. integer and R. tartessicus.     

Leaf phenological traits and leaf longevity of three mangrove species (Rhizophoraceae) on Okinawa Island, Japan

Data on leaf phenological traits and longevity of mangroves are important for improved understanding of the adaptation strategies, growth, and productivity of these trees. We studied leaf phenological traits and longevity of Rhizophora stylosa, Bruguiera gymnorrhiza, and Kandelia obovata monthly from April 2008 to March 2009. Both tree sampling (direct observation) and litterfall (indirect observation) were used. All leaves and branches of each sample tree were numbered and marked with tags at the beginning of the experiment. Peaks of leaf recruitment and death occurred in July and June, respectively, for B. gymnorrhiza and K. obovata but both occurred in July for R. stylosa. Leaf recruitment for all the species was lowest in January; leaf death was minimum in December for R. stylosa and B. gymnorrhiza, and in January for K. obovata. Leaf recruitment for the three species was significantly correlated with monthly mean air temperature and monthly hours of sunshine. K. obovata and R. stylosa leaf death was correlated with monthly mean air temperature, monthly hours of sunshine, monthly mean air vapor pressure deficit, and monthly rainfall; B. gymnorrhiza leaf death was not correlated with any environmental factors. Specific leaf area for R. stylosa (45.4?±?1.0?cm²?g^?1) and K. obovata (48.6?±?0.8?cm²?g^?1) was not significantly different, but means for these two species were significantly different from that for B. gymnorrhiza (71.0?±?2.8?cm²?g^?1). Mean leaf longevity was 13.9?months for R. stylosa, 17.2?months for B. gymnorrhiza, and 12.1?months for K. obovata. Different measured variables between B. gymnorrhiza and the other two species may have been because of the growth strategy and shade tolerance of B. gymnorrhiza. Mean leaf longevity increased with increasing mean annual air temperature.     

Isolation via enrichment and characterization of ten polymorphic microsatellite loci in the cuttlefish, Sepiella maindroni de Rochebruns

Ten novel polymorphic microsatellite loci were developed using an enrichment and colony hybridization protocol and characterized for the cuttlefish, Sepiella maindroni. Polymorphism was explored by using 30 individuals from the coastal waters of Zhanjiang, Guangdong province, China, in December 2007. The number of alleles ranged from 5 to 13. The ranges of observed and expected heterozygosity were from 0.578 9 to 1.000 0 and 0.682 8 to 0.925 7, respectively, and the average polymorphic information content (PIC) was 0.778 5. These microsatellite loci will certainly facilitate the detection of the genetic variation and population structure of S. maindroni.     

Differential reproductive strategies of two bivalves in the Dutch Wadden Sea

Cerastoderma edule and Mya arenaria are two common bivalve species in European waters. Longevity and maximum size are much greater in the latter species. Because comparison of species life-history strategies states that a long life span (i.e. high annual survival) generally goes with lower fecundity, we hypothesise that reproductive output would be lower in M. arenaria than in C. edule. In the present paper, we studied the reproductive strategies of these two species in an intertidal and a subtidal area of the western Dutch Wadden Sea, by following seasonal changes in absolute and relative weights of somatic and gonadal tissues in these bivalves. Starting of spawning was similar in the two species, around May, except for intertidal M. arenaria, which initiated spawning in August. Individual energy investment in reproduction was similar for the two species but, unlike M. arenaria, C. edule spawned completely, releasing all energy of gonadal mass in the form of gametes. Mya arenaria used the gonad not only for reproduction but also for storage. In the intertidal area, we found a trade-off between longevity and reproduction, i.e. maximum reproductive output (expressed as a proportion of body mass) was higher in C. edule than in M. arenaria. However, since body size is larger and life span longer in M. arenaria than in C. edule, mean lifetime reproductive output per individual must be higher in the first than in the latter. Based on the differences in reproductive strategies of these two species, we hypothesise that the negative effects of warming climate on bivalve population dynamics in the Wadden Sea will be stronger in C. edule than in M. arenaria.