Investigation into the possible role of androgens in the induction of hepatic vitellogenesis in the European eel:in vivo andin vitro studies

Changes in the levels of plasma vitellogenin (Vg), estradiol (E₂) and testosterone (T) were examined following gonadal development induced by carp gonadotropin treatment (cGTH) of freshwater female yellow and silver eels (Anguilla anguilla L.). The animals received injections of cGTH (250 μg kg⁻¹ body weight) or saline vehicle three times a week, for 6 to 8 weeks. No effect of vehicle was observed. Steroidogenic activity of the ovary was stimulated by cGTH treatment as shown by the increase in circulating steroid levels in both stages. However, the responses of T, E₂ and Vg differed according to the stage of development of eels. At the yellow stage, the initial steroid plasma levels were undetectable (< 0.01 ng ml⁻¹) before treatment and ovarian steroidogenic activity was slightly stimulated following cGTH treatment; steroid levels reached their highest values after 3 weeks and 6 weeks of treatment for E₂ (0.62 ± 0.13 ng ml⁻¹ and T (0.33 ± 0.30 ng ml⁻¹), respectively. The cGTH treatment slightly increased plasma Vg levels (0.2–0.7 μg ml⁻¹ during the experiment compared with the initial values of the group. At the silver stage, the initial steroid levels were detectable (0.7 ng ml⁻¹ for E₂ and 0.1 ng ml⁻¹ for T); cGTH treatment did not significantly increase plasma E₂ level which remained at initial levels. Nevertheless, plasma T levels dramatically increased from 0.1 to 3 ng ml⁻¹ and peaked after 1 or 2 weeks of cGTH treatment; a rapid increase in plasma Vg levels occurred, reaching its highest value at 5 mg ml⁻¹ after 3 weeks of treatment. Thus, the steroid kinetic profiles in relation to the appearance of Vg in the plasma following cGTH treatment was closely related to androgen levels and there was a strong vitellogenic response induced by chronic cGTH treatment. In order to test if androgens could be implicated in the vitellogenic response, we evaluated the potencies of various androgens (testosterone and 5α-androstane-3β,17β-diol)in vivo andin vitro, associated with E₂ to induce the production of Vg.In vitro experiments showed that Vg synthesis was induced by high doses (10⁻⁶ to 10⁻⁵ M) of androgen in the eel. Tamoxifen totally inhibited the action of androgens suggesting that androgens were acting through binding to the E₂ receptor.In vivo, androgens given alone at 50 μg kg⁻¹ 3 times a week for 1 months had no significant effect on plasma Vg levels. In addition, E₂-androgen cotreatment showed that the presence of androgen did not modify the vitellogenic response induced by E₂.     

The bioactivity of gonadotropin releasing hormones and its regulation in the gilthead seabream,Sparus aurata: in vivo andin vitro studies

Thein vivo andin vitro potency of native and modified forms of gonadotropin releasing hormone (GnRH) to release gonadotropin (GtH) was studied inSparus aurata and correlated with their relative susceptibility to degradation by cytosolic-bound enzymes of the pituitary, kidney, and liver. Salmon (s) GnRH and luteinizing hormone-releasing hormone (LHRH) are equipotent whereas analogs of these peptides ((D-Arg⁶-Pro⁹NET)-sGnRH, (D-Ala⁶-Pro⁹NET)-LHRH, (D-Trp⁶)-LHRH) are superactive in inducingin vivo GtH release (at 10 μg/kg body weight). In anin vitro superfusion system of pituitary fragments all analogs are equipotent to the native peptides (at 10⁻¹⁰ to 2.5 × 10⁻⁷M). sGnRH and LHRH are rapidly degraded by cytosolic peptidases of the pituitary, liver, and kidney. The preferred site of cleavage is the Tyr⁵-Gly⁶ bond. Substitution of the position 6 glycine by D-amino acids renders the 5–6 bond resistant to degradation and shifts the main site of cleavage to the Pro⁹-Gly¹⁰NH₂ bond. Substitution at position 6 (as above) and at position 10 with Pro⁹NET results in analogs that are resistant to degradation. We propose that enzymatic cleavage terminates GnRH bioactivityin vivo and thus increased resistance to degradation is a major determinant of GnRH analog superactivity.     

Accumulation of waterborne selenium by rainbow trout (Salmo gairdneri), eggs,fry and juveniles

The effect of waterborne selenite levels on selenium accumulated by different developmental stages of rainbow trout (Salmo gairdneri) was studied using⁷⁵SeO ₃ ⁼ as a tracer. All stages readily accumulated selenium at both high and low concentrations, but the rate of accumulation increased as the trout developed from the egg to the juvenile feeding stage. The low rate of selenium accumulation by embryos seemed to be related more to a lack of gills than to the presence of a chorion. The bioconcentration factor (the ratio of tissue-to-water concentrations) declined in all groups with increased waterborne selenium levels; accumulation rates appeared limited by cell permeability. At low levels of waterborne selenium (0.4μg/l), the total accumulated was small relative to existing body burdens and unlikely to contribute significantly to the nutritional requirement for selenium. High levels (45.6μg/l), however, caused considerable selenium accumulation and may be sufficient to overcome the effects of low dietary selenium.     

Involvement of Gonadotropin-Releasing Hormone in Thyroxine Release in Three different forms of Teleost Fish: Barfin Founder, Masu Salmon and Goldfish

Effects of gonadotropin-releasing hormone (GnRH) on thyroxine (T₄) release in vivo and in vitro were studied in barfin flounder Verasper moseri, masu salmon Oncorhynchus masou and goldfish Carassius auratus. Seabream GnRH (sbGnRH) at a dose of 200 ng/50 g body weight (BW) significantly increased plasma T₄ levels 1 h after the in vivo injection in the barfin flounder, but thereafter the levels normalized. Salmon GnRH (sGnRH) significantly increased plasma T₄ levels l h after the injection with a significant return to initial levels in male masu salmon and male goldfish. In contrast, sGnRH and cGnRH-II in barfin flounder, and cGnRH-II in male masu salmon and male goldfish were not effective in stimulating T₄ release. To clarify direct involvement of GnRH in T₄ release, dissected lower jaw including scattered thyroid follicles was incubated with sbGnRH (1 μg/well) in barfin flounder, and with two doses (0.1 and 1 μg/well) of sGnRH in masu salmon and goldfish in vitro. T₄ concentrations of control were stable during 24 h. Incubation of lower jaw with high dose (1 μg/well) of GnRH significantly (P<0.05) increased T₄ concentrations of incubation medium at 1 h in all experimental fishes. These results indicate that direct stimulation of T₄ secretion by GnRH occurs widely in teleost fish.     

The toxicokinetics of benzo[a]pyrene in juvenile coho salmon, Oncorhynchus kisutch, during smoltification

The activities of Phase I and Phase II biotransformation enzymes in the livers of yearling coho salmon (Oncorhynchus kisutch), were measured biweekly from February until the release date from the hatchery in mid-June, in order to observe any alterations in baseline levels during smoltification. Peak enzyme activities occurred in February and March and then declined through to June. Total cytochrome P450 levels ranged from 0.024±0.009 to 0.095±0.010 nmol mg^-1 microsomal protein, ethoxyresorufin O-deethylase activity ranged from 2.74±0.75 to 9.94±0.85 pmol min^-1 mg^-1 microsomal protein, and glutathione S-transferase activity ranged from 0.07±0.01 to 0.33±0.01 μmol min^-1 mg^-1 cytosolic protein during this period. Following an intraperitoneal injection of [3H]benzo[a]pyrene (B[a]P), elimination occurred rapidly (>71% excreted into the bile within 24h) from February to June. Although the distribution of B[a]P in tissues changed through the sampling period, the highest leels of B[a]P-derived radioactivity were found in the liver, bile and fat. Analysis of the bile revealed that 55 to 63% of the radioactivity was Phase I metabolites, 16 to 24% glucuronide conjugates, 8% sulfate conjugates, 7% other conjugates and 6% aqueous-soluble metabolites. These findings suggest that the transformation from freshwater adapted coho ‘parr’ to ‘smolts’, can significantly alter biotransformation enzyme activities and the distribution and elimination of xenobiotics such as benzo[a]pyrene in these fish. This revised version was published online in July 2006 with corrections to the Cover Date.     

转Hu-IFN-α基因草鱼雌核发育F1的遗传配型分析

The Hu-IFN-α gene, which was transducted into downstream promoter of β-actin gene of common carp (Cyprinus carpio), was recombined by DNA recombination technology. These recombined genes were injected into 1-2 cell fertilized eggs of grass carp (Ctenophatyngodon idellus) by microinjection technology, we gained transgenetic fish by molecular detection methods. In order to analyse the genetic expression of tranHu-IFN-α gene gynogensis F₁, which male individualization were gained by raising methyltestosterone, molecular genetic marker technology was used. In our research, 30 random primers were picked out from 48 and were used into RAPD-PCR, the result indicated that 1 169 clear, steady and repeated DNA finger printing bands were achieved. On the basis of gentic distance matrix among tranHu-IFN-α gene gynogenesis F₁ group, the genetic relationship of gynogenesis F₁ were analysed by UPGMA, the results showed the genetic patterns are close between the 3# male gynogenesis F₁ and the the 23# female of gynogenesis F₁, 5# and 27#, 2# and 28#, 2# and 30#. The data indicated that these group could be served as parent of tranHu-IFN-α grass carp (Ctenophatyngodon idellus) pure line.     

细角螺的繁殖生态条件及繁殖习性

Hemifusus ternatanus(Gmelin), a gastropoda living in the deep water areas of undertide,as well as a delicious seafood, was distributed mainly in Chinese southeast seas and Japanese seas near the coast. In this experiment Hemifusus ternatanus' breeding ecological conditions and its propagation habit were studied in order to provide an experimental foundation for the artificial breeding. The brood stocks of test animals collected from the waters in Taiwan Strait, and then were examinated their growing temperature， salinity, feeding and propagation habit in the laboratory. The re sults showed that the growing temperature for Hemifusus ternatanus ranges from 16 ℃ to 32 ℃, with an optimum temperature between 20 ℃ to 28 ℃ and between 23 ℃ and 28 ℃ for breeding. The optimum growth salinity was 18.3-32.3 though it much adapts to salinity from 13 to 35. They prefer to feed on bivalves particularly those with thin shells and byssusless. Hemifusus ternatanus is dioecious and fertilization finishes inside the body. It was called as egg vesicle procreation that the whole stages of embryo growth were developed within egg vesicle. Larva forms as soon as it leaves egg vesicle, which is called direct occurrence type. The larva became the juvenile after metamorphosis during 20-25 days development. It was first to obtained 233 juveniles with shell height 32-45 mm by an artificial breeding method.     

我国赤潮频发现象分析与海藻栽培生物修复作用

In this paper, the history, main events and present status of red tide (HAB, harmful algal blooms) along China coast in recent years were reviewed and presented. It showed that the HAB's frequency and scale, number of HAB spec ies, percentage of toxic HAB events and the degree of damages to marine environment and economy have sharply increased in China since 1960's. Eutrophication was key factor for high occurrence of red tide. In this paper, main causes of frequent HAB occurrence along China coast was discussed. Many factors might influence the occurrence of red tide, which included weather, climate, coastal current, tidal current, water temperature, salinity, hydrodynamic and nutrient conditions, trace metals and the variation of biological environment. Numerous evidences from all over the world revealed the linkage between the increases in nutrient loading and the occurrences of high biomass blooms. Eutrophication was one of the important causes that involved in high occurrence of HAB. The main sources of nutrients potentially stimulating HABs included terrestrial runoff, aquaculture selfpollution, atmospheric deposition, sea projects and other pollution events in the ocean. Studies showed that the input from land contaminations and the selfpollution of marine aquaculture accelerated eutrophication in coastal waters and were also important impact factors on red tide. Researches suggested that nutrient composition could affect the species composition of phytoplankton as well as the development of some HABs. The changes in nutrient supply ratios, primarily N∶P, often resulted in shifts in red tide species composition. The correlation between cysts and formation of HAB was discussed from the viewpoi nt of transformation of cyst and vegetative cell, the effects of trace elements and other organic substances on the occurrence of HAB were presented also. It indicated that the nutrient control could be an effective way to reduce the risk of red tide occurrence. Seaweed would play an important role for decreasing marine eutrophication. Among the different methods of red tide controlling studied, seaweed biomass has received much attention due to the cost saving, low sensitivity to environmental and impurity factors, the possible contaminant recovery from the biomaterial and its elevated adsorption capacity. Cultivated seaweeds have very high rates of productivity higher than that of seaweed in its natural habits and grow well in water bodies with higher nitrogen and other nutrients. Seaweeds are able to absorb large quantities of nitrogen, phosphorus and carbon dioxide, produce large quanti ties of oxygen, and have excellent effect on decreasing eutrophication. Large amounts of C, N and P are accumulated into seaweed tissues as they accumulate considerable biomass over a period of months or years depending on the cultivation season. When seaweeds are harvested, nutrients are removed from the sea area. An investigation was carried out for inorganic nitrogen and inorganic phosphorus concentration at Lusi Coast, Qidong County, Jiangsu Province in China, where there were about 270 hm2 for Porphyra yezoensis cultivation with eutrophic sea water in recent years. While during Porphyra yezoensis cultivation, from Sep 2003 to May 2004, the concentration of ammonium nitrogen declined form 0.511-0.778 mg·L^-1 to 0.006-0.057 mg·L^-1, nitrite nitrogen concentration declined from 0.010-0.040 mg·L^-1 to 0.001-0.009 mg·L^-1, and nitrate nitrogen concentration declined from 0.466-0.549 mg·L^-1 to 0.286-0.0568 mg·L^-1, the average concentration of inorganic phosphorus declined from 0.024 mg·L^-1 to 0.019 mg·L^-1. Furthermore, during five hours, the concentration of ammonium nitrogen in the seawater declined form 220.88 μmol·L^-1 to 8.59 μmol·L^-1 by cultivated Gracilaria lemanaiformis, and the concentration of ammonium nitrogen declined form 213.84 μmol·L^-1 to zero by cultivated Enteromorpha clathrata. Other bioremediation mechanisms of seaweed inhibiting the red tide microalgae such as nutrients competition and allelopathic effects were also discussed.     

Cortisol treatment improves the development of hypoosmoregulatory mechanisms in the euryhaline rainbow trout,Salmo gairdneri

The effect of cortisol on osmoregulatory parameters was studied in rainbow trout, (Salmo gairdneri), kept in freshwater (FW) and/or transferred to seawater (SW). Repeated injections of 20 μg cortisol/g fish stimulated gill and gut Na⁺/K⁺-ATPase activity and reduced plasma Na⁺ and Cl⁻ levels after 2 weeks of treatment in FW-adapted fish. Cortisol doses of 0.05 and 1.0 μg/g were without effect. Repeated injections of 10 μg cortisol/g stimulated gill Na⁺/K⁺-ATPase activity and reduced plasma Na+ and Cl⁻ levels in fish in FW, and significantly improved ion regulation after their transfer to 28SW. Higher doses of cortisol (10 and 20 μg/g) induced hyperglycemia, whereas low doses (0.05 and 1.0 μg/g were without effect or induced hypoglycemia. Plasma glucose levels decreased in cortisol-treated fish transferred to SW, whereas transient hyperglycemia was seen in the control fish.     

鳗源嗜水气单胞菌主要外膜蛋白基因克隆及其表达

A pair of primers were designed according to the published nucleotide sequence of a putative outer membrane protein gene (omp) of Aeromonas hydrophila . With the specific primers, a target fragment about 1.1 kb was amplified from Aeromonas hydrophila ML316 via PCR .The target fragment was inserted into the linearized pGEM-T easy vector. After enzyme restriction and sequencing analysis,the nucleotide data had been further analyzed by DNAman and ClutalW software. The analysis results showed that the cloned DNA fragment had a longest open reading frame (ORF) of 1035 nt,it predicted to be encoded a 344 aa protein with the molecular weight of 36 kD. Hydrophobicity analysis suggested that the protein was highly hydrophilic, especialy at the first 24 aminoacid, this region could function as signal peptide. The homologious comparison proved the cloned gene had 96% homology to the sequence of the omp gene, and the alignment of the amino acid sequence was 98% . The recombinant plasmid was constructed with the target gene and the expressing vector pGEX-4T-1 and then was transformed into E. coli BL21（DE3）by BamH and Sal I .The fusion protein was expressed under the IPTG inducing condition,and exhibited about 62 kD in size,very close to the predicted molecular weight of GSTMOMP, furthermore,the fusion protein was specifically recognized by antiserum which raised against the major outer membrane protein of AHML316. Considering all these together, it proved that the cloned gene represented the major outer membrane protein gene of AHML316, and the expressed gene products shared identical antigenicity with the natural main outer membrane protein,and also provided technical support for developing an advanced gene engineering vaccine against Aeromonas hydrophila.     

鲍疱疹病毒原位LAMP检测方法的建立与初步应用

为精确定位鲍疱疹病毒(HaHV-1)在宿主不同组织器官中的分布,明确HaHV-1的组织亲嗜性和侵染进程,实验基于环介导等温扩增技术(LAMP)和原位杂交技术建立了HaHV-1的原位LAMP检测方法。利用该方法研究了HaHV-1人工感染实验不同时间节点,病毒在杂色鲍主要器官的分布规律和组织亲嗜性。并对已报道的HaHV-1 LAMP扩增引物进行优化,实现对载玻片上原位固定靶组织内病毒DNA的稳定、特异扩增,筛选最佳显色时间等原位杂交反应条件,最后通过免疫酶标技术分析HaHV-1在组织样本内的分布情况。结果显示,HaHV-1原位LAMP检测方法最适显色时间为60 min。利用该方法对攻毒后24、36、48、60和72 h,HaHV-1在杂色鲍外套膜、鳃、肝胰腺和腹足神经节4种样本的组织分布情况进行检测和分析。病毒阳性信号最早于36 h出现在腹足神经节,48 h在部分外套膜样本中观察到病毒阳性信号,分布局限于外周神经中。在感染实验后期,病毒阳性信号出现在肝胰腺结缔组织中。病毒阳性信号出现的部位常有大量细胞渗出和浸润,渗出的细胞中可见被病毒感染的血淋巴细胞。本研究建立的HaHV-1原位LAMP检...     

团头鲂tf和tfr1a基因启动子克隆及转录调控分析

为探索鱼类转铁蛋白基因tf和转铁蛋白受体基因tfr1a的转录调控机制,本实验以团头鲂为研究对象,在其全基因组数据库中获取tf和tfr1a基因序列,对2个基因候选启动子区转录因子结合位点及CpG岛进行预测,通过PCR方法克隆得到tf和tfr1a基因近端启动子区不同长度片段,连接至pGL3-Basic/pEGFP-1载体,瞬时转染入Hela细胞,并采用双荧光素酶报告基因检测系统进行检测。结果发现,团头鲂tf基因启动子区无CpG岛位点,而tfr1a基因启动子区有2个CpG岛位点。成功构建9个tf和10个tfr1a不同长度启动子片段的重组质粒,经双荧光素酶报告基因系统检测发现,tf启动子核心区域为-268^+56 bp,且-1 308^-1 102 bp片段可能存在正调控该基因表达的转录因子结合位点;tfr1a启动子核心区域为-224^+48 bp,且+48^+92 bp可能存在抑制该基因转录的负调控元件,而-1 229^-1 219 bp区域可能存在促进tfr1a基因表达的正调控转录因子结合位点。     

Movement of the fluvial form of masu salmon, <Emphasis Type="Italic">Oncorhynchus masou masou</Emphasis>, in a mountain stream in Kyushu,Japan

Using mark-recapture methods, the movements of the fluvial form of masu salmon (Oncorhynchus masou masou) in a mountain stream on the island of Kyushu, Japan, were studied. Most (78%) of the masu salmon were recaptured in the pool in which they had been originally caught and tagged. Of those that moved between pools, the proportion of individuals that moved during the breeding period was not significantly higher than the proportion that moved during the non-breeding period. However, during the breeding period, a higher proportion of larger salmon moved than did smaller fish. The proportion of mobile large males during breeding period was higher than that for small males. Also, it was found that a few individuals showed long-range movement in the autumn. As a long-term movement, 78 individual fish (65%) that were recaptured more than three times showed high sedentary tendencies. Sixteen individual mobile fish (13%) moved and returned to the original pool. Fluvial form of masu salmon in Kyushu show a high sedentary nature; however, large mature males seem to actively move in search of female during breeding period.     

仿刺参与虾夷马粪海胆和菲律宾蛤仔混养效果的初步研究

水温13.8～20.0℃下,在容积50 L的塑料水槽中,放养体质量为(1.4±0.6)g的虾夷马粪海胆(Strongylocentrotus intermedius)11个,过量投喂海带(Laminaria japonica),再分别混养体质量为(3.4±0.6)g的仿刺参(Apostichopusjaponicus)0(A组)、3(B组)、5(C组)和10个(D组),体质量为(12.4±1.7)g的菲律宾蛤仔(Ruditapes philippim2rum)6个,排出水培养底栖硅藻和石纯(Ulva lactuca),用底栖硅藻饲喂仿刺参.77 d的饲养表明,仿刺参和海胆的成活率差异不显著(P>0.05),但混养组海胆的特定生长率(SGR)显著高于单养组(P<0.05),B、C和D组海胆的SGR分别比单养高9.12%、7.24%和10.06%,各混养组间差异不显著(P>0.05);混养海胆的饲料系数(7.28～7.70)分别显著低于单养(9.12)(P<0.05)组20.2%、15.5%和18.0%.将刺参的产量计算在内,B、C和D组海胆的饲料系数分别比对照组降低31.5%、26.8%和16.0%,但混养组间差异不显著(P>0.05).海胆和仿刺参的适宜混养比例为11:3.蛤仔和石纯生长慢,死亡率高.养殖排水培养的底栖硅藻以菱形藻(Nitzschia sp.)和卵形藻(Cocameissp.)为主,少量舟形藻(Navicula sp.).混养海胆性腺中亚麻酸、EPA DHA含量和n-3/n-6比值显著大于单养组(P<0.05),混养池水中氨氮含量低而稳,溶氧量高.     

核糖体DNA在厦门白姑鱼和大黄鱼染色体上的比较定位

为了探究石首鱼核型微观结构上的变化,实验利用荧光原位杂交(fluorescence in situ hybridization,FISH)比较定位了厦门白姑鱼和大黄鱼18S rDNA和5S rDNA的分布特征。结果表明,厦门白姑鱼与大黄鱼在宏观核型以及18S rDNA和5S rDNA染色体分布等3个方面均存在较大差异。厦门白姑鱼的核型公式为2n=48t,臂数FN=48;单对18S rDNA信号分布于1号染色体臂间;单对5S rDNA信号分布于3号染色体近着丝粒区域。大黄鱼的核型公式为2n=2sm+4st+42t,臂数FN=50;单对18S rDNA信号分布于18号染色体短臂端部;5S rDNA信号9~11对,除一对分布于臂间外,其余全部分布于着丝粒端或短臂端部。综合其他石首鱼核型数据可以推断:厦门白姑鱼呈现原始核型特征,而大黄鱼核型是原始核型经染色体重排和/或转座衍生的特化核型;石首鱼宏观核型和18S rDNA分布模式总体保守,仅少数物种存在变化,而5S rDNA位点的分布模式存在高度的种间变化。本研究首次揭示了石首鱼物种间核型微观结构的变化,为进一步开展石首鱼分子细胞遗传学研究奠定了基础。     

Use of Microbacterium sp. and Exiguobacterium mexicanum to improve the survival and development of Artemia under xenic conditions

The effect of Microbacterium sp. strain 8L and Exiguobacterium mexicanum strain 8N was evaluated in the diet of Artemia under xenic conditions. Viable cultures of bacteria were provided to xenic cultures of Artemia in combination with Sacharomyces cerevisiae, cornflour or Spirulina, and the effect on the survival and growth was recorded. The use of these bacterial strains improves significantly the survival of Artemia independently of the used food (P < 0.05), and variable results were observed in the growth.     

Identification of Stress Sensitive Genes in Hyperthermic Atlantic Salmon (Salmo salar) Embryos by RAP-PCR

Deformities of skeletal structures, the heart, and other organs are a recurrent problem in species used in intensive aquaculture. Elevated egg incubation temperature appears to be a high risk factor in the development of these malformations, but the causal relation has not been established. Our aim was to identify candidate genes involved in the development of heat induced deformities in Atlantic salmon (Salmo salar). Temperature sensitive genes were isolated by RNA Arbitrarily Primed (RAP)-PCR. A total of 33 RAP-PCR products were successfully sequenced, and the expression of eight identified genes was further examined by RT-PCR from pooled samples of heat exposed embryos. Five of these genes were demonstrated to be temperature sensitive, of which four were shown to be up-regulated and one was down-regulated at elevated water temperatures. The atrial natriuretic peptide (ANP) gene, which is a promising candidate for heart deformities, showed the highest level of heat induction. Three additional RAP-PCR products identified as heterogeneous nuclear ribonucleprotein (hnRNP) A0, acyl CoA binding protein (ACBP) and mitochondrial (mt)-HSP70 showed up-regulated mRNA expression in response to elevated water temperature. The single down-regulated gene was identified as an Atlantic salmon (Salmo salar) homolog of the cysteine and tyrosine-rich 1 (CYYR1) gene. This study demonstrated that a temperature elevation of only 4 °C during the early stages of the organogenesis in Atlantic salmon induce altered expression of a number of genes, which are candidates for the development of heat induced deformities.     

Characteristics of the marine environment and algal blooms in Gamak Bay

This study was conducted to gain insight into the characteristics of algal blooms in relation to the marine environment of Gamak Bay. From the first known occurrence of algal blooms in 1984 until 2006, 23 causal species have been identified, the most common ones being Prorocentrum sp., Cochlodinium polykrikoides, Chaetoceros sp., Skeletonema costatum, and Heterosigma akashiwo. A principal component analysis indicated that blooms of these species develop under different conditions in terms of water temperature, salinity, precipitation, and insolation. Field data showed Cochlodinium polykrikoides to be favored by high temperatures and to be euryhaline, whereas Skeletonema costatum appeared to be eurythermal and euryhaline. Prorocentrum sp. and Chaetoceros sp. appeared to be stenothermal and stenohaline. Finally, Heterosigma akashiwo appeared at the lowest temperature and highest salinity of the five species and was classified here as stenothermal and stenohaline.     

黄芪多糖和当归多糖对维氏气单胞菌诱导鲫细胞凋亡的影响

为研究黄芪多糖(APS)和当归多糖(ASP)对维氏气单胞菌诱导鲫细胞凋亡的影响,实验设阴性对照组、阳性对照组,黄芪多糖组和当归多糖组,通过对鲫用维氏气单胞菌攻毒处理,用流式细胞仪测定血细胞的凋亡比例和细胞周期变化,并用荧光显微镜和透射电镜观察凋亡细胞的形态。结果显示,维氏气单胞菌攻毒后阳性对照组鲫血细胞的细胞凋亡率均极显著高于多糖组和阴性对照组;多糖组能显著降低鲫的细胞凋亡率且黄芪多糖组效果更显著;攻毒后鲫肝细胞和肾脏淋巴细胞出现染色质凝集、细胞核固缩边集和细胞空泡化及凋亡小体;同阴性对照组相比;维氏气单胞菌攻毒可以引起鲫血细胞周期中S/G2+M期细胞比例极显著下降,sub-G1极显著升高,抑制细胞分裂诱发凋亡;多糖组则G0/G1期细胞极显著降低,S/G2+M期细胞极显著升高,sub-G1极显著降低,促进细胞分裂抑制凋亡。黄芪多糖和当归多糖添加量在1%时能抑制维氏气单胞菌攻毒引起的细胞凋亡。     

青鱼和鲇肠道排泄物对养殖水体铜绿微囊藻休眠体复苏的影响及作用途径

为探讨养殖水体底栖鱼类肠道排泄物对铜绿微囊藻休眠体复苏的影响,将青鱼和鲇肠道排泄物与铜绿微囊藻休眠体用野外养殖水域沉积物(底泥)混匀包埋,在10、15和20°C梯度温度下进行休眠体复苏实验。结果显示,铜绿微囊藻休眠体主要复苏期为第3～15天,在10和15°C条件下,青鱼排泄物组(MP)、鲇排泄物组(SA)和青鱼-鲇排泄物混合组(MP-SA)铜绿微囊藻休眠体复苏率均显著高于对照组(CK),且MP组也显著高于SA组和MP-SA组;在20°C条件下,MP组铜绿微囊藻休眠体复苏率显著高于SA组、MP-SA混合组和CK组,但SA组和MP-SA组与CK组复苏率并无显著性差异。实验过程中MP组沉积物中优势菌群以假单胞菌为主,SA组和MP-SA组优势菌群分别以芽孢杆菌和厚壁菌为主,第0～12天为菌群增殖期,且此期间沉积物-水体界面(SWI)实验MP组、SA组和MP-SA组溶解氧含量(DO)和氮磷比(N/P)均显著低于对照组。研究表明,青鱼和鲇肠道排泄物能促进铜绿微囊藻休眠体复苏,且这种促复苏效果在低温区间(10～15°C)更显著,可能是排泄物中菌群在生长增殖期降低了沉积物-水体界面N/P和DO的结果。研究结果对养殖水体底泥清淤和春季铜绿微囊藻水华防控具有一定的理论意义。