刺参Apostichopus japonicus (Selenka)耐高温品系选育的基础研究

刺参是目前支撑我国海水增养殖业高效、稳定、持续发展的重要物种之一，但该产业面临着种质匮乏、病害严重、养殖环境局部恶化和产品品质难以保证等诸多问题。本文围绕刺参增养殖过程中的种质苗种问题，以培育耐高温品系为研究目标，在评价我国沿海不同地理群体刺参及其子一代在热刺激条件下HSP70基因mRNA表达差异的基础上，以低纬度地理群体为亲本，经温度刺激后比较了幼体及幼参的生长及HSP70 mRNA表达差异，获得了性状优良的耐高温群体。主要研究结果如下： 1、研究了我国沿海刺参不同地理群体在热激后HSP70基因mRNA的表达差异，比较了在不同温度下不同地理群体幼参的生长特性。青岛、日照和养殖等低纬度群体成参HSP70基因mRNA表达变化较大连、长岛等高纬度群体明显；热激后低纬度群体幼参HSP70基因mRNA表达量较高纬度群体高；高温条件下，高纬度群体子一代成活率低生长。温度升高对高纬度群体生长的影响较大。 2、利用荧光实时定量PCR检测了HSP70基因在不同组织、不同温度、不同时间mRNA水平的表达差异。刺参的各组织都有HSP70的mRNA表达，且对热刺激都有应答。自然水温12℃时，在＋12℃温度刺激时刺参的呼吸树中的HSP70 mRNA水平较高；刺参成参、幼参呼吸树中HSP70基因的mRNA水平在热激后6-12h达到最高；低温刺激后HSP70 mRNA下调表达。 3、分别从受精卵和初耳幼体开始在不同温度下进行幼体培育， 27℃以上温度培育的刺参幼体，其生长和成活率显著低于24℃以下温度培育的幼体；不同起始刺激阶段和不同温度都是显著影响因子。从初耳幼体进行高温培育，幼体的变态受到明显影响，26℃以上温度培育幼体的变态率显著低于24℃以下培育温度。 4、以日照刺参为亲本，在26℃培育温度下获得了耐高温群体幼参，并从生长、HSP70mRNA水平的表达差异与常温培育的群体（普通群体）进行了比较。耐高温群体幼参在较高温度下成活率和HSP70mRNA表达水平明显高于普通群体，而二者在特定生长率随温度变化上没有差异。 5、在浙江苍南进行了选择群体耐高温能力和生长验证实验。耐温群体的温度耐受能力提高了0.7℃，进入夏眠时间延后15d左右。耐温刺参群体的特定生长率和成活率在3月温度回升后远高于对照组。

中国海蓝子鱼科Family Siganidae分类和动物地理学特点

蓝子鱼科鱼类隶属于鲈形目、刺尾鱼亚目，广泛分布于我国东海、南海及台湾海域。本文根据中国科学院海洋研究所多年来在我国海域采集并收藏的以及部分补充采集的蓝子鱼标本，参考国际最新研究资料，对我国海域蓝子鱼科鱼类进行分类和动物地理学研究，共记录中国海域蓝子鱼科鱼类1属2亚属11种。经研究分析，得到如下结论： 1.中国沿海蓝子鱼科鱼类的多样性问题。国内曾有13种蓝子鱼的分布记录，其中蠕纹蓝子鱼Siganus vermiculatus和暗体蓝子鱼S. punctatissimus仅以前的学者做过名录形式的记载，并无标本收藏，本文中不做介绍。此外尖嘴蓝子鱼Siganus unimaculatus也可能存在于中国海域，有待于进一步研究。目前确定在中国海域有分布的蓝子鱼为11种，约占世界总种数（27）的40％多，种的多样性较高。 2. 形态学比较研究说明，蓝子鱼在体形、体色、牙齿、头骨、椎骨、耳石等特征方面存在种间差异，可作为蓝子鱼科鱼类分类的有效鉴别特征。对于外部形态极其相似的种，可借助内部解剖特征相辅助予以区分。 3．对蓝子鱼动物地理学特点研究分析结论如下：a.中国海域存在的11种蓝子鱼在印度－太平洋海域均有分布，没有地方特有种。b.长鳍蓝子鱼和褐蓝子鱼在我国东海、台湾海域和南海均有分布，褐蓝子鱼在黄海北部亦有分布，种群数量较大；其它9种，除凹吻蓝子鱼仅分布于南海外，均分布于南海及台湾海域，种群数量较小。c.中国海域蓝子鱼种类组成与邻近的菲律宾、马来西亚、印度尼西亚海域比较相似，中国分布的种类在这些海域均有分布，且分布于这一区域而中国没有记录的有5种。与日本相比，种类组成也比较相似，中日共有种达9种，仅分布于中国海域2种，仅分布于日本海域1种。 4. 作者参照国际最新研究结果和较为公认的分类系统Nelson（1994），将蓝子鱼科置于刺尾鱼亚目，而不再使用国内学者长期惯用的蓝子鱼亚目。蓝子鱼科包括一属蓝子鱼属Siganus Forsskål, 1775，两亚属：蓝子鱼亚属Siganus Forsskål, 1775 和罗蓝子鱼亚属 Lo Seale, 1906，同时使全部种名的变动和确定与国际最新研究结果(Woodland, 1990; 2001）取得一致。

刺参Apostichopus japonicus营养成分、食物来源及消化生理的季节变化

本文从消化生理学角度出发，研究了刺参营养成分、食物来源以及消化道结构与功能的季节变化，并对养殖水温对刺参消化道结构与功能的影响及与夏眠之间的关系进行了探讨。主要研究结果如下： 1.较为系统地评述了我国刺参增养殖业的现状及存在的问题；对海参的营养成分研究进行了综述和展望；对刺参的消化生理及其夏眠的研究进行了综述并提出了新见解和思路。 2.研究了刺参体壁营养成分的季节变化（2006年7月-2007年6月）。结果表明刺参体壁的基本营养成分及氨基酸、脂肪酸的含量具有显著的季节变化；氨基酸组成全面，平均氨基酸得分（AAS）在75.79-85.17之间，其中8月最高，1月最低；脂肪酸种类丰富，饱和脂肪酸（SFA）相对含量季节变化显著，8月份最高，1月份最低；单不饱和脂肪酸（MUFA）季节变化不显著；多不饱和脂肪酸（PUFA）相对含量具有明显的季节变化，其变化规律与SFA相反，8月份最低，1月份最高；综合分析表明刺参的营养价值在冬季的11月、1月最高。 3.用脂肪酸标志法分析了刺参食物来源组成情况及季节变化（2006年7月-2007年6月）。1月份刺参的主要食物来源是硅藻、鞭毛藻或原生动物、褐藻以及细菌（变形细菌和革兰氏阴性菌），3月份是硅藻、鞭毛藻或原生动物和大型绿藻。6月份大型绿藻在刺参的食物来源中占据较大比重。7月份细菌（噬纤维菌-黄杆菌类、革兰氏阳性菌）和大型绿藻的食物贡献较大。细菌（噬纤维菌-黄杆菌类、革兰氏阳性菌）在8、9月份的食物来源中占较大比重。褐藻和细菌（变形细菌和革兰氏阴性菌）在10、11月的食物贡献较大。 4.现场研究了刺参消化道和消化酶活性的季节变化（2006年6月到2007年6月）。结果表明：刺参的消化酶活性和消化道性状指标均有显著的季节变化。典型夏眠期的9月份，刺参的相对消化道重量（RGM）和Zihler’s 指数分别降低到全年最高值的8.2% 和28.0%。夏眠期间刺参的消化道指数与淀粉酶、脂肪酶、胰蛋白酶、纤维素酶、褐藻酸酶活性都很低，但胃蛋白酶活性很高，且远高于非夏眠期；分析表明Zihler’s指数可以反应刺参的食性，而相对RGM则可反应刺参的摄食状况。 5.研究了养殖水温（7°C、14°C、21°C、28°C，40天）对刺参消化道结构与功能的影响及与夏眠的关系。室内模拟研究结果表明7°C养殖水温下刺参的RGM最高；在7°C和14°C的养殖水温下，RGM没有显著变化。刺参在21°C下的第40天和28°C下的前20天进入夏眠前期，在28°C下的第30-40天进入夏眠期；在夏眠前期和夏眠期，刺参的RGM以及淀粉酶、脂肪酶和胰蛋白酶活性下降，而胃蛋白酶活性显著升高；分析表明高温和积温是引发刺参夏眠不可或缺的外界因素。

中国海豆蟹科Family Pinnotheridae分类学研究

本文根据中国科学院海洋研究所收藏的豆蟹科标本和国内外相关文献，进行了中国海域豆蟹科的分类学研究。作者克服了豆蟹科分类难度大，研究积累较少，种的界限不清等困难，在短期内初步查清了中国海域豆蟹科种类及分布情况，共记述5亚科12属 40种。发现4新记录属，9新记录种，和豆蟹属1未定种Pinnotheres sp.，丰富了中国海豆蟹科区系内容，列出了共栖种中国海域全部记录过的宿主。 作者对鉴定过程中出现的疑难问题：“中型三强蟹Tritodynamia intermedia Shen, 1935是否为霍氏三强蟹 Tritodynamia horvathi Nobili, 1905的同物异名” 进行了细致比较、研究，否定了通行多年的Sakai（1976）的“T. intermedia Shen为T. horvathi Nobili的次异名”的结论，肯定了二者均为有效种。 对中国海域豆蟹科种类地理分布初步研究表明其分布与日本海域和东南亚海域都有相似之处，但有显著不同：仅发现于中国海域而未见于日本海域的豆蟹属Pinnotheres多达8种：涨腹豆蟹Pinnotheres excussus Dai et al., 1980，球豆蟹Pinnotheres pilulus Dai et al., 1980，锯颚豆蟹Pinnotheres serrignathus Shen, 1932，宽豆蟹Pinnotheres dilatatus Shen, 1932，青岛豆蟹Pinnotheres tsingtaoensis Shen, 1932，海阳豆蟹Pinnotheres haiyangensis Shen, 1932，钝颚豆蟹Pinnotheres obtusidentata（Dai et al., 1980），光豆蟹Pinnotheres luminatus Dai et al., 1980）；仅发现于中国海域的三强蟹属Tritodynamia有4种：福建三强蟹Tritodynamia fujianensis Chen, 1979，长腿三强蟹Tritodynamia longipropodum Dai et al., 1980，宽身三强蟹 Tritodynamia dilatatum Yang et Sun,1996和海南三强蟹 Tritodynamia hainanensis Dai et al.g, 1980；而未发现于中国海域的日本特有种多达13种。结果表明这一类群由于共栖和地域分化程度较高乃至地区性特有种数显著较多。 论文通过对豆蟹科系统分类和初步的动物地理学研究，搞清了中国海豆蟹科的种和分布、多样性及其宿主等基本情况。为今后研究豆蟹科种类生物学、生态学特性提供了基础资料。

虾夷扇贝Patinopecten yessoensis (Jay)和仿刺参Apostichopus japonicus (Seienka)多倍体诱导研究

本文采用化学方法诱导了虾夷扇贝Patinopecten yessoensis (Jay)和仿刺参Apostichopus japonicus (Selenka)的多倍体。采用6－二甲基氨基嘌呤（6－dimethylaminopurine）抑制虾夷扇贝极体释放，研究了诱导三倍体的实验条件、技术工艺以及三倍体虾夷扇贝幼虫的生长和培育方法。结果表明，使用6－二甲基氨基嘌呤（6－DMAP）可诱导17.3%-100.0%的三倍体虾夷扇贝面盘幼虫。筛选并优化了生产中操作简便、高效、成活率高的诱导条件，并研究出在扇贝三倍体诱导中批量获得受精卵、处理及培育的技术工艺，对扇贝三倍体的规模化诱导及培育等生产性应用具有较高的参考价值。报道了采用细胞松弛素B（cytochalasin B）、秋水仙素（colchicine）、6－DMAP以及咖啡因（coffeine）等药物抑制虾夷扇贝第一极体（PB_1）释放、PB_1和第二极体（PB_2）释放以及抑制第一次卵裂等方法诱导四倍体的结果。结果表明，CB、6－DMAP和秋水仙素抑制扇贝第一次有丝分裂诱发四倍体的比例低于25%，而采用CB抑制PB_1可有效地诱导产生四倍体，从授精后42min提前到15-22min开始处理，抑制PB_1的放出有助于提高四倍体的比例，在12 ℃，处理开始和终上时间分别在授精后20－22min和60－62min时，面盘幼虫四倍体率最高，为56.5%。对CB处理抑制受精卵PB_1释放的处理组胚胎的染色体分离状况进行了观察研究。对照组受精卵具有19条四分体染色体，经过减数分裂I期（meiosis I）和减数分裂II期（meiosis II），放出PB_1和PB_2，受精卵的发育具有不同步性。处理组受精卵在第二次减数分裂中出现了“三级分离“、“联合二级分离“和“独立二级分离“等特殊的分离类型，初步分析了CB抑制第一极体放出的机理。对三倍体虾夷扇贝的繁殖潜力和卵子的大小进行了观察研究，三倍体扇贝具一定的繁殖能力，三倍体雌贝平均产卵3.26 * 10~6个，而相同壳长二倍体贝为1.45 * 10~7，三倍体产卵量仅为二倍体产卵量的22.5%。三倍体卵子产出后，形状不规则，卵子平均直径为87.25μm，比二倍体大11.7%，卵子体积比二倍体大39.4%。利用CB抑制第一极体释放诱导了虾夷扇贝的四倍体，诱导率为41.5%。首次报道了仿刺参Apostichopus japanicus (Selenka)多倍体诱导的结果。采用紫外线照射的海水成功地使海参分别单独产卵、排精，从而准确地控制了海参的人工授精后处理的时间。采用0.2、0.4mg/L CB 抑制受精卵第一极体释放以及10、20、30和40mg/L 的6－DMAP 分别抑制PB_1、PB_2放出的方法诱导了仿刺参的多倍体。研究了诱导的药物浓度、处理时间以及处理开始时间等，同时对幼体的成活率等进行了探讨。结果表明，2种药物均可诱导仿刺参产生三倍体和四倍体，从效果上看，采用CB抑制PB_1诱导，到达小耳幼体时，可产生9.7%-21.3%的四倍体。6－DMAP抑制PB_2放出诱导三倍体，三倍体诱导率介于7.5%-25.8%之间。

Morphological and ultrastructural characterization of the coelomocytes in Apostichopus japonicus

The coelomocytes suspended in the coelomic fluid and occurring in the coelomic epithelial layer of the sea cucumber Apostichopus japonicus (Selenka) (Holothuroidea: Aspidochirota: Stichopodidae) function as mediators of the immune system, trephocytic cells and nutrient transport cells. Types of coelomocytes are characterized based on their morphological and ultrastructural features. Flow cytometry plus light and electron microscopic analyses were conducted in order to characterize the coelomocytes of A. japonicus. Six types of coelomocytes were identified: lymphocytes, morula cells, amoebocytes, crystal cells, fusiform cells and vibratile cells. Within these major categories, several distinctive cell types occurred that might represent developmental stages. The mean +/- SD coelomocyte concentration in the individuals (body length: 10 to 15 cm; weight: 100 to 150 g) was (3.79 +/- 0.65) X 10(6) cells ml(-1). The coelomic fluid contained mainly hyalinocytes (76.69%) and granulocytes (23.31 %).

Effects of body size and water temperature on food consumption and growth in the sea cucumber Apostichopus japonicus (Selenka) with special reference to aestivation

To investigate the effects of body size and water temperature on feeding and growth in the sea cucumber Apostichopus japonicus (Selenka), the maximum rate of food consumption in terms of energy (C-maxe; J day(-1)) and the specific growth rate in terms of energy (SGRe; % day(-1)) in animals of three body sizes (mean +/- SE) - large (134.0 +/- 3.5 g), medium (73.6 +/- 2.2 g) and small (36.5 +/- 1.2 g) - were determined at water temperatures of 10, 15, 20, 25 and 30 degrees C. Maximum rate of food consumption in terms of energy increased and SGRe decreased with increasing body weight at 10, 15 and 20 degrees C. This trend, however, was not apparent at 25 and 30 degrees C, which could be influenced by aestivation. High water temperatures (above 20 degrees C) were disadvantageous to feeding and growth of this animal; SGRe of A. japonicus during aestivation was negative. The optimum temperatures for food consumption and for growth were similar and were between 14 and 15 degrees C, and body size seemed to have a slight effect on the optimal temperature for food consumption or growth. Because aestivation of A. japonicus was temperature dependent, the present paper also documented the threshold temperatures to aestivation as indicated by feeding cessation. Deduced from daily food consumption of individuals, the threshold temperature to aestivation for large and medium animals (73.3-139.3 g) was 24.5-25.5 degrees C, while that for small animals (28.9-40.7 g) was between 25.5 and 30.5 degrees C. These values are higher than previous reports; differences in sign of aestivation, experimental condition and dwelling district of test animals could be the reasons.

Effect of water temperature on digestive enzyme activity and gut mass in sea cucumber Apostichopus japonicus (Selenka), with special reference to aestivation

The effect of water temperature on gut mass and digestive enzyme activity in sea cucumber Apostichopus japonicus, including relative gut mass (RGM), amylase, lipase, pepsin and trypsin activities were studied at temperatures of 7, 14, 21, and 28A degrees C over a period of 40 days. Results show that RGM significantly decreased after 40 days at 21A degrees C and markedly decreased over the whole experiment period at 28A degrees C; however, no significant effect of duration was observed at 7 or 14A degrees C. At 14A degrees C, trypsin activity significantly decreased over 10 and 20 days, then increased; amylase and trypsin activity significantly decreased after 40 days at 28A degrees C. However, no significant effect of duration was found on amylase, pepsin or trypsin activities in the other temperature treatment groups. At 28A degrees C, lipase activity peaked in 20 days and then markedly decreased to a minimum at the end of the experiment. On the other hand, pepsin activity at 28A degrees C continuously increased over the whole experimental period. Principle component analysis showed that sea cucumbers on day 40 in the 21A degrees C group and in the previous 20 days in the 28A degrees C group were in the prophase of aestivation. At 28A degrees C, sea cucumbers aestivated at 30-40 days after the start of the experiment. It is concluded that the effect of temperature on the digestion of A. japonicus is comparatively weak within a specific range of water temperatures and aestivation behavior is accompanied by significant changes in RGM and digestive enzyme activities.

Bioenergetic responses of sub-adult sea cucumber Apostichopus japonicus (Selenka) (Echinodermata: Holothuroidea) to temperature with special discussion regarding its southernmost distribution limit in China

1. This paper investigated the bioenergetic responses of the sea cucumber Apostichopus japonicus (wet weights of 36.5 +/- 1.2 g) to different water temperatures (5, 10, 15, 20, 25 and 30 degrees C) in the laboratory. 2. Results showed that theoretically the optimal temperatures for energy intake and scope for growth (SFG) of sub-adult A. japonicus was at 15.6 and 16.0 degrees C, respectively. The aestivation threshold temperature for this life-stage sea cucumber could be 29.0 degrees C by taking feeding cessation as the indication of aestivation. 3. Our data suggests that A. japonicus is thermo-sensitive to higher temperature, which prevents it from colonising sub-tropical coastal zones. Therefore, water temperature plays an important role in its southernmost distribution limit in China. 4. The potential impact of global ocean warming on A. japonicus might be a northward shift in the geographical distribution. Crown Copyright (C) 2009 Published by Elsevier Ltd, All rights reserved.

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.

Modulatory effects of ammonia-N on the immune system of Penaeus japonicus to virulence of white spot syndrome virus

To study response to white spot syndrome virus (WSSV) under ammonia stress, Penaeus japonicus were exposed to 5 mg l(-1) ammonia-N and challenged orally with WSSV (NW). Controls consisted of an ammonia-N-exposed control group (N), a WSSV-challenged positive control group (W), and an untreated control group (control). Immune parameters measured were total haemocyte count (THC), haemocyte phagocytosis, plasma protein content and haemolymph enzymatic activities for prophenoloxidase (proPO), alkaline phosphatase (ALP), and nitric oxide synthase (NOS). THC and plasma protein had downward trends with time in all treatment groups (NW, N, and W) in contrast to the untreated control group (control). The percentage phagocytosis, NOS activity, and ALP and proPO activity of W and NW decreased initially then increased from 6 to 78 h (except for NOS and ALP, from 6 to 54 h) before declining thereafter until the end of the experiment. Compared with untreated controls (control), there was a downward trend for all measured parameters in the treatment groups (N, NW, and W), but the degree was W > NW > N. WSSV was detected at 78 h postchallenge in both W and NW. In conclusion, 5 mg l(-1) ammonia-N reduced the immunocompetence of P japonicus and may have decreased the virulence of WSSV (C) 2004 Elsevier B.V. All rights reserved.

Spatial distribution of ciliates, copepod nauplii and eggs, Engraulis japonicus post-larvae and microzooplankton herbivorous activity in the Yellow Sea, China

The abundance of anchovy Engraulis japonicus larvae, >20 mum ciliates, copepod eggs and nauplii, and microzooplankton herbivorous activity were studied in the Yellow Sea in June 2000. Anchovy juveniles and larvae were found in only 6 of the 19 stations sampled. The ciliate communities were dominated by 2 species: Laboea strobila and Strombidium compressum. In the surface waters, the abundance of L. strobila ranged between 0 and 560 ind. l(-1). S. compressum only appeared at Stns 15 to 18 (20 to 3300 ind. l(-1)). L. strobila was found mainly in the top 20 m. The abundance of L. strobila was less than 50 ind, l(-1) in waters deeper than 25 m. S, compressum showed subsurface abundance peaks at the salinity abnormality. Tintinnids occurred occasionally with abundance lower than 100 ind. l(-1), The total ciliate abundance fell in the range of 40 to 3420 ind. l(-1). The ciliate biomass in the surface water and the water column ranged between 0,15 and 6.76 mug C l(-1) and 0.4 and 134.4 mg C m(-2), respectively, In the surface waters, the abundance of copepod eggs and nauplii ranged from 0,3 to 3.1 and 1,1 to 15.6 ind, l(-1), respectively. The average abundance of copepod eggs and nauplii in 4 depth (0, 5, 10 and 20 m) fell in the range of 0.2 to 2.8 and 1.0 to 29.4 ind. l(-1), respectively. As a food item of the E. japonicus post-larvae, the abundance of copepod nauplii and eggs appeared to be low. The abundance peaks of ciliate and E, japonicus post-larvae coincided. Although not found in the gut of E, japonicus post-larvae, aloricate ciliates might be ingested by first-feeding anchovy larvae, preventing initial starvation and prolonging the time to irreversible starvation. On the basis of dilution experiments with positive microzooplankton grazing rates, microzooplankton grazed at rates of 0 to 0.61 d(-1). Grazing pressure of microzooplankton on chlorophyll a standing stock (P-i) and potential chlorophyll a primary production (P-p) were 17 to 46% and 35 to 109% d(-1), respectively.

Phenotypic plasticity of gut structure and function during periods of inactivity in Apostichopus japonicus

Apostichopus japonicus is a common sea cucumber that undergoes seasonal inactivity phases and ceases feeding during the summer months. We used this sea cucumber species as a model in which to examine phenotypic plasticity of the digestive tract in response to food deprivation. We measured the body mass, gross gut morphology and digestive enzyme activities of A. japonicus before, during, and after the period of inactivity to examine the effects of food deprivation on the gut structure and function of this animal. Individuals were sampled semi-monthly from June to November (10 sampling intervals over 178 days) across temperature changes of more than 18 degrees C. On 5 September, which represented the peak of inactivity and lack of feeding, A. japonicus decreased its body mass, gut mass and gut length by 50%, 85%, and 70%, respectively, in comparison to values for these parameters preceding the inactive period. The activities of amylase, cellulase and lipase decreased by 77%, 98%, and 35% respectively, in comparison to mean values for these enzymes in June, whereas pepsin activity increased two-fold (luring the inactive phase. Alginase and trypsin activities were variable and did not change significantly across the 178-day experiment. With the exception of amylase and cellulase, all body size indices and digestive enzyme activities recovered and even surpassed the mean values preceding the inactive phase during the latter part of the experiment (October-November). Principal Component Analysis (PCA) utilizing the digestive enzyme activity and body size index data divided the physiological state of this cucumber into four phases: an active stage, prophase of inactivity peak inactivity, and a reversion phase. These phases are all consistent with previously suggested life stages for this species, but our data provide more defined characteristics of each phase. A. japonicus clearly exhibits phenotypic plasticity (or life-cycle staging) of the digestive tract during its annual inactive period. (C) 2008 Elsevier Inc. All rights reserved.

Studies on the transmission of WSSV (white spot syndrome virus) in juvenile Marsupenaeus japonicus via marine microalgae

We studied the possible role that marine microalgae may play during the outbreaks of WSS (white spot syndrome). In order to elucidate the possibility of marine microalgae carrying WSSV (white spot syndrome virus), six marine microallgae (Isochr.vsis galbana, Skeletonema costatum, Chlorella sp., Heterosigma akashiwo, Scrippsiella trochoidea, Dunaliella salina) were co-cultured with adult Marsupenaeus japollicus infected with WSSV and were assayed daily by nested-PCR to study whether they could carry WSSV. Further experiments were conducted to investigate whether the virus carried by microalgae could re-infect juvenile M. japonicus. Results showed that all of the experimental microalgae, except H. akashiwo could carry WSSV, and among them, Chlorella sp. and S. trochoidea had the strongest WSSV-carrying ability. Unlike other invertebrate carriers of WSSV, the WSSV detections in microalgae, which were positive after I and 3 days, were negative after 10 days of incubation. WSSV detection results in juvenile M. japonicus showed that the juvenile shrimp were re-infected by co-cultured Chlorella sp., although the juvenile M. japonicus carried so small an amount of WSSV that it could only be detected by nested-PCR. The results of this experiment suggest that microalgae might be one possible horizontal transmission pathway for WSSV. Further research, however, is required to better understand the factors behind the different carrying abilities and virus-carrying mechanisms of different microalgae. (c) 2007 Elsevier Inc. All rights reserved.