河鲈微卫星引物筛选

利用GenBank中获得的近缘物种微卫星序列设计的20对引物,对河鲈养殖群体20个个体基因组DNA进行扩增,发现8对引物能扩增出特异性谱带,获得32个等位基因,5个位点的等位基因数大于或等于4个,多态信息含量0.3680～0.7395,5个位点多态信息含量为高度多态(PIC＞0.5).期望杂合度范围在0.4154～0.7936,观测杂合度普遍高于期望杂合度.个体识别率范围在0.180～0.620,累积个体识别率为0.9899,单一微卫星位点的个体识别率普遍低于0.8,未出现高度多态性遗传标记.非父排除率范围在0.2537～0.6185,累积非父排除率0.9937,4个位点的非父排除率高于0.5,属于高度多态性遗传标记.     

仿刺参的微卫星标记

为了评价种质资源及基础生物学研究的需要，本文开发了仿刺参的微卫星标记。NCBI数据库中共有20个含有仿刺参微卫星的序列，从中选取8个设计引物，发现6个微卫星位点有多态性。不同的引物获得的等位基因数为3～9个不等，6个位点共获得了31个等位基因，每个位点平均获得5．2个等位基因。6个位点的平均观测杂合度（Ho）为0．3611，平均期望杂合度（He）为0．6402。位点AJMS004提供的多态性信息含量值较低，为0．4862；其他5个位点均在0．5以上。另外，还尝试了红海参（Parastichopus californicus）微卫星标记在仿刺参的通用性。实验结果表明，在较高的退火温度下，5对引物均能扩增仿刺参的基因组DNA并具多态性。5个位点共获得了22个等位基因，每个位点平均获得4．4个等位基因。5个位点的平均观测杂合度（Ho）为0．1733，平均期望杂合度（He）为0．4201。其中位点Psc2的多态性信息含量值最高，为0．8500。     

三角帆蚌微卫星位点筛选及多态性分析

采用磁珠富集法,以生物素标记的(CA)10寡核苷酸为探针,构建了三角帆蚌(Hyriopsis cumingii)基因组微卫星富集文库。根据微卫星位点的侧翼序列设计引物,随机挑选扩增出与预期大小相符的32对引物,引物荧光标记后对24个三角帆蚌个体分别进行PCR扩增,共筛选出20对多态性较好的引物。结果表明,20个微卫星位点的等位基因数为5～20,有效等位基因数2.321 3～13.260 3。观察杂合度和期望杂合度分别为0.318 2～1.000 0和0.582 5～0.946 1;PIC值0.547 2～0.919 9;其中14个位点符合Hardy-Weinberg平衡(P>0.05)。本研究筛选的20个微卫星标记可作为三角帆蚌遗传多样性、种群遗传结构等研究的理想分子标记。     

微卫星标记BM3413和OB2在5个绵羊群体中多态性的研究

选用萨福克、德国美利奴、特克塞尔、乌珠穆沁、以及右玉本地绵羊5个绵羊群体共250个个体,通过耳组织提取基因组DNA,用2对微卫星引物进行PCR扩增,通过电泳分型、凝胶成像系统分析各位点等位基因及全部个体的标记基因型,计算基因频率、多态信息含量(PIC)和杂合度等,从分子水平上分析5个绵羊品种的遗传多态性。结果表明,BM3413和OB2这2个位点的等位基因数分别为7和8,多态信息含量PIC﹥0.5,杂合度为0.8271～0.8467,均属于高度多态性位点,用于作为与生产性能相关的遗传标记是较理想的。     

中华倒刺鲃微卫星标记筛选及特征分析

以乌江流域中华倒刺鲃(Spinibarbus sinensis)为材料,构建了中华倒刺鲃微卫星富集文库。以乌江彭水电站所采集的32个个体的基因组DNA为模板,进行PCR扩增,结果筛选出8个多态性微卫星位点,其等位基因数4~10,多态信息含量0.6072~0.8515;观测杂合度0.5625~1.0000,期望杂合度0.6791~0.8795,Hardy中华倒刺鲃微卫星标记筛选及特征分析Weinberg平衡偏离指数-0.2009~0.3805;卡方检验结果表明,3个位点不同程度地偏离了Hardy中华倒刺鲃微卫星标记筛选及特征分析Weinberg平衡(P<0.05);各位点两两之间不存在显著的连锁不平衡现象。     

中华倒刺鲃微卫星标记筛选及特征分析

以乌江流域中华倒刺鲃(Spinibarbus sinensis)为材料,构建了中华倒刺鲃微卫星富集文库。以乌江彭水电站所采集的32个个体的基因组DNA为模板,进行PCR扩增,结果筛选出8个多态性微卫星位点,其等位基因数4~10,多态信息含量0.6072~0.8515;观测杂合度0.5625~1.0000,期望杂合度0.6791~0.8795,Hardy中华倒刺鲃微卫星标记筛选及特征分析Weinberg平衡偏离指数-0.2009~0.3805;卡方检验结果表明,3个位点不同程度地偏离了Hardy中华倒刺鲃微卫星标记筛选及特征分析Weinberg平衡(P<0.05);各位点两两之间不存在显著的连锁不平衡现象。     

长江宜宾江段圆口铜鱼遗传多样性的微卫星分析

选用实验室克隆的23个圆口铜鱼(Coreius guichenoti Sauvageet Dabry)微卫星标记分析了长江宜宾江段的圆口铜鱼群体遗传多样性,统计分析了有效等位基因数、观测杂合度Ho、期望杂合度He、多态信息含量(PIC)等遗传学指标。结果表明:23个位点有14个微卫星位点呈单态,9个位点出现多态,在这9个位点中共检测到48个等位基因,其平均有效等位基因数为5.3,多态信息含量在0.440～0.839之间变动,平均为0.670,除YT17和YT22位点属于中度多态外,其余7个位点均属于高度多态。平均观测杂合度为0.753,平均期望杂合度为0.728,表明该群体的遗传多样性较为丰富。     

金沙江观音岩段圆口铜鱼的微卫星遗传多样性分析

选用10对微卫星引物,对金沙江观音岩江段圆口铜鱼(Coreius guichenoti)群体的遗传多样性进行研究。统计分析了有效等位基因数、观测杂合度、期望杂合度、多态信息含量等遗传学指标,结果显示所选用的10对微卫星引物均表现为高度多态性,共检测到等位基因数84个,平均有效等位基因数5.429 6;观测杂合度0.800 0~0.933 3、期望杂合度0.774 7~0.841 4;多态信息含量为0.649~0.753;Shannon’s指数为1.523 7~2.260 2;Hardy-Weinberg平衡偏离指数为0.032 6~0.127 7。结果表明该江段圆口铜鱼群体遗传多样性较丰富。     

泥蚶34个EST-SSR标记的开发及在格粗饰蚶中的通用性检测

利用泥蚶转录组高通量测序、拼接获得的大量EST序列开发SSR标记,在1123条EST序列里筛查到73条含有SSR位点的EST序列,其中54个位点适合设计引物,在位点两侧设计引物并进行PCR扩增.结果显示,46对引物获得稳定扩增的位点,引物在泥蚶奉化群体的多态性检测中发现,有34对引物表现出多态性,共扩增出122个等位基因,各位点的等位基因数Na为2～7个,平均每个位点产生3.59个等位基因,观测杂合度Ho、期望杂合度He、多态信息含量PIC范围分别为0.000 ～ 0.600、0.078 ～0.771、0.106～0.718;Hardy-Weinberg平衡检测显示,13个位点偏离了平衡状态;用Nr和Swiss-Prot蛋白质数据库对含有多态性SSR的EST进行了基因注释,25个SSR位点来自注释基因序列.将34对泥蚶多态性SSR引物在格粗饰蚶中进行了通用性检测,结果有1 1对成功扩增,8对表现为多态,通用率为23.53％,这些通用引物可用于两种蚶的遗传多样性评价、系统进化分析、比较作图和基因发掘等研究.     

多倍体中华鲟微卫星亲子鉴定体系的建立

应用荧光引物和自动测序技术,检测了10个自主研发的微卫星分子标记在68个中华鲟(Acipenser sinensis)个体中的遗传多态性。结果表明,10个微卫星标记共检测到124个等位基因,等位基因数为7~22,期望杂合度为0.730 26~0.873 95,Shannon-Wiener多样性指数为1.561 61~2.219 60。基于亲子鉴定排除率不低于0.99的标准,最终确定Asi-75067、Asi-67648、Asi-67123、Asi-73843、Asi-72040、Asi-70421和Asi-56700等7个微卫星标记为中华鲟亲子鉴定的核心体系,其单亲、父权和双亲的累积排除率分别为99.12%、99.95%和99.99%。该微卫星标记组合为中华鲟准确高效经济的亲子鉴定体系建立提供了科学依据。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.     

Migratory dynamics of stream-spawning longnose gar (Lepisosteus osseus)

Abstract– Literature evidence suggests that lake-dwelling longnose gar (Lepisosteus osseus) enter tributary streams to spawn, Until the present study, the dynamics of this breeding migration had never been investigated quantitatively. During the summers of 1991 and 1992, longnose gar were captured as they entered Weaubleau Creek, Missouri, a tributary of Harry S. Truman Reservoir. The in-stream spawning migration began in early April and ended in late May, and was positively correlated with stream flow and water level, and negatively correlated with water temperature. In-stream residence times ranged from 15 to 94 days, with males exhibiting longer residence times than females. Once in-stream, longnose gar travelled as far as 10 km upstream and occupied certain pools at greater relative frequencies. Although the reason for this preferential utilization is not completely understood, it may relate to pool depth and riffle proximity. Longnose gar disperse from the spawning stream great distances, with gar captured in Weaubleau Creek being recaptured up to 48 km away. This information should provide fisheries biologists the means to consider the reproductive ecology of this species in their conservation and management decisions.     

Nutritional regulation of hepatocyte fatty acid desaturation and polyunsaturated fatty acid composition in zebrafish (Danio rerio) and tilapia (Oreochromis niloticus)

The desaturation and elongation of [1-¹⁴C]18:3n-3 was investigated in hepatocytes of the tropical warm freshwater species, zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus). The hepatocyte fatty acid desaturation/elongation pathway was assayed before and after the fish were fed two experimental diets, a control diet containing fish oil (FO) and a diet containing vegetable oil (VO; a blend of olive, linseed and high oleic acid sunflower oils) for 10 weeks. The VO diet was formulated to provide 1% each of 18:2n-6 and 18:3n-3, and so satisfy the possible EFA requirements of zebrafish and tilapia. At the end of the dietary trial, the lipid and fatty acid composition was determined in whole zebrafish, and liver, white muscle and brain of tilapia. Both zebrafish and tilapia expressed a hepatocyte fatty acid desaturation/elongation pattern consistent with them being freshwater and planktonivorous fish. The data also showed that hepatic fatty acid desaturation/elongation was nutritionally regulated with the activities being higher in fish fed the VO diet compared to fish fed the FO diet. In zebrafish, the main effect of the VO diet was increased fatty acid Δ6 desaturase activity resulting in the production of significantly more 18:4n-3 compared to fish fed the FO diet. In tilapia, all activities in the pathway were greater in fish fed the VO diet resulting in increased amounts of all fatty acids in the pathway, but primarily eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). However, the fatty acid compositional data indicated that despite increased activity, desaturation of 18:3n-3 was insufficient to maintain tissue proportions of EPA and DHA in fish fed the VO diet at the same level as in fish fed the FO diet. Practically, these results indicate that manipulation of tilapia diets in commercial culture in response to the declining global fish oil market would have important consequences for fish fatty acid composition and the health of consumers. Scientifically, zebrafish and tilapia, both the subject of active genome mapping projects, could be useful models for studies of lipid and fatty acid metabolism at a molecular biological and genetic level. This revised version was published online in August 2006 with corrections to the Cover Date.     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.