Differential population structuring and demographic history of two closely related fish species, Japanese sea bass (Lateolabrax japonicus) and spotted sea bass (Lateolabrax maculatus) in Northwestern Pacific

The Quaternary cold periods in the Northwestern Pacific are thought to have heavily influenced the amount and distribution of intraspecific genetic variation in marine fishes. To estimate the demographic history and genetic structure of Lateolabrax macula

cDNA cloning and mRNA expression of the translationally controlled tumor protein (TCTP) gene from Japanese sea perch (Lateolabrax japonicus)

A homologue of the lower vertebrates translationally controlled tumor protein (TCTP) was cloned from the marine fish Japanese sea perch (Lateolabrax japonicus) by the technology of homology cloning. The full-length cDNA sequence of the sea perch TCTP gene contained a 5' untranslated region (UTR) of 47 bp, a 3' UTR of 433 bp, and a putative open reading frame (ORF) of 510 bp encoding a polypeptide of 170 amino acids. The deduced amino acid sequence of the sea perch TCTP gene showed a high similarity to that of zebrafish, rohu, rabbit, chicken and human. Sequence analysis revealed there were a signature sequence of TCTP family, an N-glycosylation site, and five Casein kinase phosphorylation sites in the sea perch TCTP. The temporal expression of TCTP genes in healthy and lipopolysaccharide (LPS) challenged fishes was measured by semi-quantitative reverse transcription-PCR (RT-PCR). The results indicated that LPS could up-regulate the expression of sea perch TCTP in the examined tissues, including head-kidney, spleen and liver.

The complete amino acid sequence of growth hormone and partial amino acid sequence of prolactin and somatolactin from sea perch (Lateolabrax japonicus)

Growth hormone (GH), prolactin (PRL) and somatolactin (SL) were purified simultaneously under alkaline condition (pH 9.0) from pituitary glands of sea perch (Lateolabrax japonicas) by a two-step procedure involving gel filtration on Sephadex G-100 and reverse-phase high-performance liquid chromatography (rpHPLC). At each step of purification, fractions were monitored by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and by immunoblotting with chum salmon GH. PRL and SL antisera. The yields of sea perch GH, PRL and SL were 4.2, 1.0 and 0.28 mg/g wet tissue, respectively. The molecular weights of 19,200 and 20,370 Da were estimated by SDS-PAGE for sea perch GH and PRL, respectively. Two forms of sea perch SL were found: one (28,400 Da) is probably glycosylated, while the other one (23,200 Da) is believed to be deglycosylated. GH bioactivity was examined by an in vivo assay. Intraperitoneal injection of sea perch GH at a dose of 0.01 and 0.1 mug/g body weight at 7-day intervals resulted in a significant increase in body weight and length of juvenile rainbow trout. The complete sea-perch GH amino acid sequence of 187 residues was determined by sequencing fragments cleaved by chemicals and enzymes. Alignment of sea-perch GH with those of other fish GHs revealed that sea-perch GH is most similar to advanced marine fish, such as tuna, gilthead sea bream, yellowfin porgy, red sea bream, bonito and yellow tail with 98.4, 96.2%, 95.7%, 95.2%, 94.1% and 91% sequence identity, respectively. Sea-perch GH has low identity to Atlantic cod (76.5%), hardtail (73.3%), flounder (68.4%), chum salmon (66.3%), carp (54%) and blue shark (38%). Partial amino-acid sequences of 127 of sea-perch PRL and the N-terminal of 16 amino-acid sequence of sea-perch SL have been determined. The data show that sea-perch PRL has a slightly higher sequence identity with tilapia PRL( 73.2%) than with chum salmon PRL(70%) in this 127 amino-acid sequence. (C) 2001 Elsevier Science B.V. All rights reserved.

Structural analysis of SNARE motifs from sea perch, Lateolabrax japonicus by computerized approaches

Three cDNA sequences encoding four SNARE (N-ethylmaleimide-sensitive fusion protein attachment protein receptors) motifs were cloned from sea perch, and the deduced peptide sequences were analyzed for structural prediction by using 14 different web servers and softwares. The "ionic layer" structure, the three dimensional extension and conformational characters of the SNARE 7S core complex by using bioinformatics approaches were compared respectively with those from mammalian X-ray crystallographic investigations. The result suggested that the formation and stabilization of fish SNARE core complex might be driven by hydrophobic association, hydrogen bond among R group of core amino acids and electrostatic attraction at molecular level. This revealed that the SNARE proteins interaction of the fish may share the same molecular mechanism with that of mammal, indicating the universality and solidity of SNARE core complex theory. This work is also an attempt to get the protein 3D structural information which appears to be similar to that obtained through X-ray crystallography, only by using computerized approaches. (C) 2007 Elsevier Ltd. All rights reserved.

塔玛亚历山大藻(Alexandrium tamarense)对鲈鱼(Lateolabrax japonicus) 的危害机制研究

本论文选择在我国分离得到的一株有毒赤潮甲藻-塔玛亚历山大藻（Alexandrium tamarense，ATHK株），研究了其对一种我国沿海常见和典型养殖鱼类鲈鱼（Lateolabrax japonicus）的危害机制。首先研究了塔玛亚历山大藻（ATHK）对鲈鱼鳃结构的影响及其溶血毒性； 然后采用腹腔注射的方法，研究了高剂量塔玛亚历山大藻毒素（ATHK毒素：约为1.6×105 细胞，相应PSP为0.886µg STX Equal，相当于每克湿重的鲈鱼PSP注射量为0.0118µg STX Equal）和低剂量塔玛亚历山大藻毒素（ATHK毒素： 约为0.16×105 细胞，相应PSP为0.0886µg STX Equal，相当于每克湿重的鲈鱼PSP注射量为0.00118µg STX Equal）在鲈鱼体内代谢过程中对鲈鱼肝脏、肾脏和鳃组织的超微结构、Na+K+-ATPase活性、肝脏功能和肾脏功能的影响、以及对抗氧化系统酶活性和异生物质代谢酶的影响，以期从不同方面了解塔玛亚历山大藻及其所产水溶性毒素（ATHK毒素）对鲈鱼的毒害效应及机制，为有毒赤潮的有效管理提供一定的科学依据。 塔玛亚历山大藻（ATHK）对鲈鱼鳃组织影响的实验结果表明，该藻使鲈鱼鳃组织出现水肿现象，细胞间隙变大；粘液细胞颗粒不规则，颜色加深，颗粒发生凝集，有板结状；氯细胞线粒体内部基质凝集。不产PSP的一种亚历山大藻（AT-6）也使鲈鱼鳃出现水肿，且使细胞出现一定的固缩现象。显微镜观察发现鲈鱼鳃丝间存在有这两种亚历山大藻细胞。由此推测塔玛亚历山大藻ATHK和AT-6的表面结构可能具有能导致鲈鱼鳃组织水肿的机械作用。对人血细胞溶血实验结果表明塔玛亚历山大藻（ATHK）具有较强的溶血毒性，大小与藻的生长阶段和细胞密度都有一定的关系：指数期的溶血毒性最大，随细胞数目的增多，活性逐渐加大；藻细胞、细胞碎片、细胞内容物都有一定的溶血毒性，其中细胞碎片的活性最大。通过11种（株）产PSP的亚历山大藻、不产PSP的亚历山大藻以及标准PSP的实验结果表明这种溶血毒性是由藻细胞的其它非PSP物质造成的，且这种溶血毒性在产PSP的亚历山大藻中具有一定的普遍性。 塔玛亚历山大藻（ATHK）对鲈鱼组织超微结构实验结果表明：ATHK毒素（约为1.6×105 细胞，相应PSP为0.886µg STX Equal，相当于每克湿重的鲈鱼PSP注射量为0.0118µg STX Equal）能导致鲈鱼组织细胞超微结构发生剧烈的变化，主要表现在：肝细胞细胞膜有肿胀现象，部分膜边缘溶解；细胞质糖原颗粒化；核糖体脱落，仅见滑面内质网；细胞质和线粒体内都出现空泡，且线粒体的嵴状结构也发生变化；核膜溶解比较严重，核质外溢，且异染色质边际化。前肾细胞超微结构的变化主要是淋巴细胞核质出现空泡，核膜有溶解迹象；Ⅰ型粒细胞颗粒膨大，伪足增多且变长；Ⅱ型颗粒细胞颗粒增多，内部出现空腔，细胞膜和核膜溶解，胞质、细胞器和核质外溢。鳃组织中氯细胞的核膜局部溶解，核仁弥散，线粒体膜溶解，微细小管膨大；粘液颗粒膜溶解，内部结构遭受破坏；扁平细胞核膜及线粒体膜几乎全部溶解。因此，我们的结果表明，ATHK毒素能作用于鲈鱼细胞的内膜和外膜系统，使膜发生溶解、脱落等变化；比较注射同样剂量大小ATHK毒素120h和240h时鲈鱼组织超微结构发现，细胞超微结构在一定程度上能够恢复。 ATHK毒素对Na+K+-ATPase活性、肝脏功能以及肾脏功能的影响结果表明，0.16×105―1.6×105细胞范围内的ATHK毒素可以显著影响肝脏和鳃组织中的Na+K+-ATPase，使这两种组织中的Na+K+-ATPase活性出现不同程度的下降； 而且还能够显著抑制肝脏中谷丙转氨酶的活性，最大抑制率为95%。但此范围内的ATHK毒素不能显著影响肾脏中的Na+K+-ATPase活性以及尿素氮含量。因此，ATHK毒素对Na+K+-ATPase活性的抑制则会导致细胞能量的缺失，使细胞进一步发生其它变化，而ATHK毒素对肝脏功能完整性的影响则可能会抑制对蛋白质的分解代谢。 ATHK毒素对鲈鱼肝脏、肾脏和鳃组织中的、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱肝肽过氧化物酶（GSH-Px）以及谷胱肝肽转硫酶（GST）活性变化影响的结果表明：高剂量（约为1.6×105 细胞，相应PSP为0.886µg STX Equal，相当于每克湿重的鲈鱼PSP注射量为0.0118µg STX Equal）ATHK毒素能显著诱导鲈鱼肝脏和鳃组织中SOD、GSH-Px以及GST酶活性，最大变化范围为正常状态下的3-4倍，对肝脏中CAT酶活性具有一定的抑制作用，对鳃中的CAT抑制效应则不显著；但此剂量的ATHK毒素仅对肾脏鳃中的GSH-Px活性有一定的诱导作用，对SOD、CAT以及GST的活性没有显著影响。低剂量（约为0.16×105 细胞，相应PSP为0.0886µg STX Equal，相当于每克湿重的鲈鱼PSP注射量为0.00118µg STX Equal）ATHK毒素也能诱导鲈鱼肝脏和鳃组织中SOD、GSH-Px以及GST酶活性，其在第一个24h内的诱导效果与临界致死毒素剂量相似； 且连续注射低剂量ATHK毒素则对肝脏和鳃中这三种酶活性具有累加的诱导作用，使这三种酶活性的变化范围为正常的5倍；低剂量ATHK毒素对肝脏中CAT酶活性也具有抑制作用，但对鳃中CAT酶活性的抑制作用并不显著。 同样，低剂量ATHK毒素除对肾脏中GSH-Px活性具有一定诱导效应外，对SOD、CAT以及GST都没有显著影响。 SOD、GSH-Px以及GST酶活性的显著升高表明ATHK毒素在鲈鱼体内代谢过程中能诱导鲈鱼产生活性氧自由基，且GST活性的升高则说明作为细胞色素P450依赖的异生物质代谢酶，GST在ATHK毒素代谢过程中可能可以加速ATHK毒素的代谢。推测鲈鱼可以通过这三种酶降低ATHK毒素以及次生毒物活性氧自由基对鲈鱼的危害。

Comparative researches on effects of sodium dodecylbenzene sulfonate and sodium dodecyl sulfate upon Lateolabrax japonicus biomarker system

Fish Lateolabrax japonicus were exposed to anion surfactant sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS) at 1 mg/l, respectively, for 6, 12 and 18 d, with one control group. Liver antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH) and glutathione S-transferase (GST) were determined; brain acetylcholinesterase (AChE) and liver inducible nitric oxide synthase (NOS) activities were also measured. The results of the study indicated that these parameters made different, sometimes, adverse responses to SDBS and SDS exposure, such as the activity of NOS can be inhibited by SDBS and induced by SDS, the different physico-chemical characteristics of SDBS and SDS should be responsible for their effects on enzyme activities. (c) 2005 Elsevier B.V. All rights reserved.

Response of integrated biomarkers of fish (Lateolabrax japonicus) exposed to benzo[a]pyrene and sodium dodecylbenzene sulfonate

Fish Lateolabrax japonicus were exposed to 0.1 and 1 mg/L of anion surfactant sodium dodecylbenzene sulfonate (SDBS) and to 2 and 20 mu g/L of benzo[a]pyrene (B[a]P) for 6, 12, and 18 days, with control and solvent control groups. Liver antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), and glutathione S-transferase (GST), were determined; brain acetyleholinesterase (AChE) and liver inducible nitric oxide synthase (iNOS) activities were also measured. The results indicated that (1) L. japonicus avoided oxidative damage through antioxidant systems; (2) SOD, GPx, and GSH were induced, and GST was inhibited and then induced by B[a]P exposure; and (3) CAT, GPx, and AChE were induced while NOS was inhibited, and GST was induced and then inhibited by SDBS stress in experimental period. (c) 2005 Elsevier Inc. All rights reserved.

粘孢子纲新科的代表——安永七囊虫SEPTEMCAPSULA YASUNAGAI,新属新种

<正> 日本国安永统男先生(Norio Yasunaga, 1981)报道在日本长崎五岛一些养殖场饲养的花鲈 Lateolabrax japonicus发生一种粘孢子虫病,引起严重死亡。他从病鱼脑腔里找到这种病原体的孢囊标本,赠给作者两块,以研究它的形态结构和分类问题。通过对标本的详细观察、研究,认为这种粘孢子虫的孢子,形态结构比较特殊,不仅足以作为独立的属,而且是一新科的代表。

肉食性鱼类补偿生长特性的研究

本文主要以花鲈[Lateolabrax．japonicus (C．& V．)]和褐牙鲆[Paralichthys olivaceus(T. & S.)]作为海洋肉食性鱼类的代表种类，根据鱼类生态生理学理论，通过设定不同饥饿时问下因子水平，研究两种鱼类摄食率、排粪率、转化效率和SGR等生态生理效率的状态变化。其目的在于研究高营养级鱼类在海洋生态系统中的下行控制作用(Top-down Effect)，以及肉食性鱼类的生态对策与鱼类资源补充机制的相互关系，为深入解析鱼类资源生产力及其持续利用海洋生物资源，提供科学依据。其主要研究结果概述如下：1．花鲈： 饥饿0(对照组)、4、8、12、16d后恢复投喂，过量投喂淡水桡足类，温度为19.5±2.0℃，初始体重为0.61-0.93g，平均体重为0．79g实验周期为28d。1.1饥饿时间对花鲈的体重损失率产生显著影响，受过饥饿的个体的湿重失率 (LR_W)与饥饿时间(t)的关系为：LR_W=2.2164t-3.6634(r~2=0.9767，p13d)的个体的排粪率显著大于其它各组，其它各组间排粪率差异不显著；2.2在整个实验周期36d内，对照组与经受3—8d饥饿的实验组的SGR显著大于经受饥饿时间大于lOd的实验组，饥饿3-8d的完全补偿生长，饥饿10-15d 的个体发生部分补偿生长，饥饿18d的个体不能补偿生长；经受饥饿个体的摄食率低于对照组；除了饥饿18d的个体的饵料转化率显著小于对照组外，其它各组的转化率没有显著差异；经受长时间饥饿(>13d)的个体的排粪率显著大于其它各组，其它各组问没有显著的差异。2．3平均体重为2．59g的褐牙鲆，饥饿至不可恢复点(PNR)的时间大于18d。3．花鲈和褐牙鲆在经受饥饿后的体重损失率与饥饿的时间正相关。在实验期间，花鲈体重损失率与饥饿时间成一次线性关系，褐牙鲆体重损失率与饥饿时间成对数函数关系。在饥饿后均会发生补偿生长。3.1比较研究结果，表明在适当时间饥饿后的个体均会发生补偿生长，其超生长速度与饥饿时间密切相关。花鲈在饥饿至不可恢复点的临界状态时发生最强烈的超生长现象，而褐牙鲆则是在饥饿3—5d后恢复投喂时可以观测到最高速度的超生长。3.2经受适当时间饥饿后的个体在短期内，其摄食率大于对照组的摄食强度。曾经饥饿的时间越长，花鲈在饥饿结束后的摄食率越高，褐牙鲆在饥饿结束后的高摄食率持续的时间越长。3.3经受适当时间饥饿后的个体，在短期内的转化率均会大于对照组的转化 效率，且随饥饿时间而加强；高转化效率持续的时间与饥饿时间无关。褐牙鲆的高转化率持续的时间很短，且很快下降至低于对照组的水平，其下降程度与饥饿时问成正相关，经受过度饥饿的花鲈和褐牙鲆转化率显著低于对照组。3．4花鲈的补偿生长是饵料转化率提高的结果；而褐牙鲆的补偿生长的原因则因其经受的饥饿程度而异。从饥饿后恢复投喂较短的时间周期(4d和6d)看，花鲈和褐牙鲆的补偿生长是转化率和摄食率共同提高的结果；但从饥饿后恢复投喂较长的时问周期(12d和1 8d)看，经受短期(4-8d)饥饿的花鲈的补偿生长是转化率显著提高的结果，而经受长期(12d)饥饿的花鲈的补偿生长是转化率显著提高的结果，褐牙鲆则是摄食率显著提高的结果。3．5从整个实验周期来看，对花鲈的饥饿降低了其生长速度和饵料转化率，但对褐牙鲆的短期饥饿(<8d)不会降低其生长速度，也不会影响一定时间(3-13d)饥饿的个体的饵料转化率。

Transfer of paralytic shellfish toxins via marine food chains: A simulated experiment

Objective To study the transfer of paralytic shellfish toxins (PST) using four simulated marine food chains: dinoflagellate Alexandrium tamarense -> Arterriia Artemia salina -> Mysid shrimp Neomysis awatschensis; A. tamarense-N. awatschensis: A. taniarense A. salina -> Perch Lateolabrax japonicus; and A. tamarense -> L. japonicus. Methods The ingestion of A. tamarense, a producer of PST, by L. japonicus, N. awatschensis, and A. salina was first confirmed by microscopic observation of A. tamarense cells in the intestine samples of the three different organisms, and by the analysis of Chl.a levels iii the samples. Toxin accumulation in L. japonicus and N. awatschensis directly from the feeding on A. tamarense or indirectly ibrough the vector of A. salina was then studied. The toxicity of samples was measured using the AOAC mouse bioassay method, and the toxin content and profile of A. tamarense were analyzed by the HPLC method. Results Both A. salina and N. awatschensis could ingest A. tamarense cells. However, the ingestion capability of A. salina exceeded that of N. awatschensis. After the exposure to the culture of A. tamarense (2 000 cells(.)mL(-1)) for 70 minutes, the content of ChLa in A. salina and N. awatschensis reached 0.87 and 0.024 mu g-mg(-1), respectively. Besides, A. tamarense cells existed in the intestines of L. japonicus, N. awatschensis and A. salina by microscopic observation. Therefore, the three organisms could ingest A. tamarense cells directly. A. salina could accumulate high content of PST, and the toxicity of A. salina in samples collected on days 1, 4, and 5 of the experiment was 2.18, 2.6, and 2.1 MU(.)g(-1), respectively. All extracts from the samples could lead to death of tested mice within 7 minutes, and the toxin content in arternia sample collected on the 1st day was estimated to be 1.65x10(-5) pg STX equa Vindividual. Toxin accumulation in L. japonicus and N. awatschensis directly from the feeding on A. tamarense or indirectly froin the vector of A. salina was also studied. The mice injected with extracts from L. japonicus and N. awatschensis samples that accumulated PST either directly or indirectly showed PST intoxication symptoms, indicating that low levels of PST existed in these samples. Conclusion Paralytic shellfish toxins can be transferred to L. japonicus, N. awatschensis, and A. salina from A. taniarense directly or indirectly via the food chains.

Genetic evidence for natural hybridization between Red Snow Crab (Chionoecetes japonicus) and Snow Crab (Chionoecetes opilio) in Korea

Both red snow crab (Chionoecetes japonicus Rathbun, 1932) and snow crab (Chionoecetes opilio Fabricius, 1788) are commercially important species in Korea. The geographical ranges of the two species overlap in the East Sea, where both species are fished commercially. Morphological identification of the two species and putative hybrids can be difficult because of their overlapping morphological characteristics. The presence of putative hybrids can affect the total allowable catch (TAC) of C. japonicus and C. opilio, and causes problems managing C. japonicus and C. opilio wild resources. To date, however, no natural hybridization has been reported between C. japonicus and C. opilio, despite their overlapping distributions along the coast of the East Sea. In this study, the internal transcribed spacer (ITS) region of major ribosomal RNA genes from the nuclear genome and the cytochrome oxidase I (CO I) gene from the mitochondrial genome were sequenced to determine whether natural hybridization occurs between the two species. Our results revealed that all putative hybrids identified using morphological traits had two distinct types of ITS sequences corresponding to those of both parental species. Mitochondrial CO I gene sequencing showed that all putative hybrids had sequences identical to C. japonicus. A genotyping assay based on single nucleotide polymorphisms in the ITS1 region and the CO I gene produced the most efficient and accurate identification of all hybrid individuals. Molecular data clearly demonstrate that natural hybridization does occur between C. japonicus and C. opilio, but only with C. japonicus as the maternal parent.

Effect of environmental conditions on the distribution of Pacific mackerel (Scomber japonicus) larvae in the California Current system

We modeled the probability of capturing Pacif ic mackerel (Scomber japonicus) larvae as a function of environmental variables for the Southern California Bight (SCB) most years from 1951 through 2008 and Mexican waters offshore of Baja California from 1951 through 1984. The model exhibited acceptable fit, as indicated by the area under a receiver-operating-characteristic curve of 0.80 but was inconsistent with the zero catches that occurred frequently in the 2000s. Two types of spawners overlapped spatially within the survey area: those that exhibited peak spawning during April in the SCB at about 15.5°C and a smaller group that exhibited peak spawning in August near Punta Eugenia, Mexico, at 20°C or greater. The SCB generally had greater zooplankton than Mexican waters but less appropriate (lower) geostrophic f lows. Mexican waters generally exhibited greater predicted habitat quality than the SCB in cold years. Predicted quality of the habitat in the SCB was greater from the 1980s to 2008 than in the earlier years of the survey primarily because temperatures and geostrophic flows were more appropriate for larvae. However, stock size the previous year had a larger effect on predictions than any environmental variable, indicating that larval Pacific mackerel did not fully occupy the suitable habitat during most years.