超高效液相色谱串联质谱法测定鱼组织中6种抗雌激素药物

采用超高效液相色谱-串联质谱(UPLC-MS/MS)在多反应监测(MRM)模式下建立了鱼肉、鱼肝中6种抗雌激素类药物(托瑞米芬、氯米芬、他莫昔芬、雷洛昔芬、阿那曲唑、来曲唑)的检测方法。样品采用乙腈超声提取,上清液中加入适量水稀释提取液,经混合型阳离子交换(MCX)固相萃取柱富集、净化后进行UPLC-MS/MS分析。UPLC分离在ACQUITY UPLCTM BEH C18柱(100 mm×2.1 mm, 1.7 μm)上进行,以乙腈和0.1%甲酸水溶液为流动相进行梯度洗脱。6种抗雌激素药物的定量限(以信噪比为10计)为0.1～0.3 μg/kg; 4个加标水平的平均回收率为84.9%～112.2%,相对标准偏差为0.9%～14.3%。该方法可用于鱼肉、鱼肝中6种抗雌激素药物的痕量分析。     

Modern methods of improving the range accuracy of CTFM sonars

In a CTFM (continuous transmission frequency modulated) sonar, the error in range measurement is usually dominated by the low resolution of the range coding frequency of the system. Modern real time spectrum analysers using 1024 point DFTs (discrete Fourier transforms) can display the range codes of the sonar at a resolution approximately equal to 0.2%. To produce a range code accurate to half of the resolution, the linearity of the CTFM sweep must, however, be kept as low as 0.01%. This requirement creates several difficulties in the design of the frequency sweep when both non-linearity and stability of the voltage-controlled oscillator (VCO) and of the controlling voltage ramp are to be considered. A practical approach for achieving the above specifications is described. Properties of electronic components and of state of the art devices and the restrictions of their operating conditions are discussed. Illustrations are given for two measuring instruments: an underwater sonar system for quantitative assessment of fish population, and a diagnostic sonar.     

A Novel Nano-Sensor Based on Rhodamine-β-Isothiocyanate – Doped Silica Nanoparticle for pH Measurement

A novel and simple enzymatic method for the determination of trace cyanide in marine fish is presented. This method is based on the conversion of metal-cyanide complexes by a fungal enzyme extract containing cyanide hydratase (E.C. 4.2.1.66; CyHT) and formamidase (E.C. 3.5.1.49) into formate and ammonia. The formate produced in the sample pretreated with the fungal enzymes was measured by adding formate dehydrogenase (E.C. 1.2.1.2; FDH) and excess NAD⁺. The NADH formed accordingly was monitored at 340nm. The cyanide calibration curve was found to be linear in the range of 10–100µM, and the detection limit was 1.1µM (0.0286ppm). The proposed biotest was successfully applied to the determination of trace cyanide in a tropical marine food fish species (Russells Snapper (Lutjamus russellii)) which had been exposed to cyanide.     

A note on optimal fish harvest

Some relatively simple techniques are applied to a singular control problem arising in bioeconomics. First, Stokes' theorem is applied to the fixed-endpoint problem. This reduces the free-endpoint problem to a problem in ordinary calculus. It is then possible to find an explicit expression for the switching manifold, which generalizes the results obtained by Cliff and Vincent (Ref. 1).     

美国红鱼(Sciaenops ocellatus)的鱼苗特性及苗种运输技术

美国红鱼的鱼苗阶段以轮虫和卤虫为主要饵料，鱼苗生长迅速，孵化后约25d即为体长3．0cm左右的幼鱼．对体长2．0～7.0cm鱼苗的运输试验结果表明，美国红鱼苗对长时间运输的耐受力较强．在水温24℃以下，尼龙袋和帆布桶运输10h以内的运输成活率均在94％以上．引起鱼苗死亡的临界DO为2．2mg／L.     

Development of non-lethal sampling of carbon and nitrogen stable isotope ratios in salmonids: effects of lipid and inorganic components of fins

The preferred tissue for analyses of fish stable isotope ratios for most researchers is muscle, the sampling of which typically requires the specimen to be sacrificed. The use of non-destructive methods in fish isotopic research has been increasing recently, but as yet is not a standard procedure. Previous studies have reported varying levels of success regarding the utility of non-lethally obtained stable isotope materials, e.g. fins, but none have accounted for the potential compounding effects of inorganic components of fin rays or lipids. Comparisons of carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotope ratios of muscle with adipose and caudal fin of two salmonids, Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.), revealed that caudal fin can be used as a non-destructive surrogate for muscle in stable isotope analysis, but that adipose fin, where available, is a better proxy. The use of a published model to inexpensively counteract the confounding effect of lipids, which are depleted in ¹³C, greatly improved the relationship between fish muscle and fins. However, efforts to account for the inorganic components of fin rays were counterproductive and required twice the biomass of fins clipped from each fish. As this experiment was conducted on wild fish, controlled laboratory studies are required to confirm these field observations.     

Preparation of eicosapentaenoic acid ethyl ester from fish oil ethyl esters by continuous batch chromatography

Fish oils are rich in eicosapentaenoic acid, which has the wide‐ranging biological activities. The rapid and efficient separation of eicosapentaenoic acid ethyl ester from fish oils ethyl ester is still regarded as a challenge. In this study, we described an effective and flexible chromatography for eicosapentaenoic acid ethyl ester preparation, named continuous batch chromatography, which combined the batch chromatography with the continuous chromatographic operation mode. After continuous batch chromatography experiment, the recovery of eicosapentaenoic acid ethyl ester was 82.01%, the average relative purity and the relative highest purity of eicosapentaenoic acid ethyl ester were 97.82 and 98.98%. The productivity of continuous batch chromatography was 5.48 times higher than that of batch chromatography, while the solvent consumption of eicosapentaenoic acid ethyl ester was 78% of the batch chromatography. This study provided a reference for the separation of the targeted chemical component from multi‐component mixtures.     

Development of Fish Immunity and the Role of β-Glucan in Immune Responses

Administration of β-glucans through various routes, including immersion, dietary inclusion, or injection, have been found to stimulate various facets of immune responses, such as resistance to infections and resistance to environmental stress. β-Glucans used as an immunomodulatory food supplement have been found beneficial in eliciting immunity in commercial aquaculture. Despite extensive research involving more than 3000 published studies, knowledge of the receptors involved in recognition of β-glucans, their downstream signaling, and overall mechanisms of action is still lacking. The aim of this review is to summarize and discuss what is currently known about of the use of β-glucans in fish.     

Experimental and numerical study of an aquaculture net cage with floater in waves and current

The mooring loads on an aquaculture net cage in current and waves are investigated by dedicated model tests and numerical simulations. The main purpose is to investigate which physical effects are dominant for mooring loads, and in this respect, to investigate the validity of different rational hydrodynamic load models. Also structural and numerical aspects are investigated. The model tests are performed to provide benchmark data, while the numerical model is used to study the effect and sensitivity of different load models and parameters.Compared to a realistic aquaculture plant, the total system is simplified to reduce the complexity. The system does, however, include all the four main components of an aquaculture plant: net cage, floater, sinker weights and moorings. The net cage is bottomless, flexible and circular. It is attached to a circular, elastic floater at the top and has 16 sinker weights at the bottom. The system is nearly linearly moored with four crow feet mooring lines.The loads are measured in the four mooring lines. A systematic variation of current only, wave only as well as combined current and wave conditions is carried out. The numerical simulation results are first benchmarked towards the experimental data. The mean loads in general dominate over the dynamic part of the loads in combined current and waves, and they significantly increase in long and steep waves, relative to current only. Next, a sensitivity study is carried out. A rigid floater significantly alters the loads in the mooring lines compared to a realistic, elastic floater. The theoretical model for the wave matters. The mooring loads are rather insensitive to a majority of the parameters and models, in particular: frequency dependent added mass of the floater and nonlinear restoring loads. It seems not to be necessary to represent the net cage with a very fine numerical mesh.     

应用可视芯片技术高通量鉴别8种鱼成分

为探索鱼肉品种快速鉴别方法,以鱼类小清蛋白基因为靶标,设计了多宝鱼、银鲳鱼、金枪鱼、暗纹东方鲀、青石斑鱼、带鱼、大黄鱼以及东星斑鱼8种鱼的通用引物以及特异性探针,利用可视芯片技术,建立了一种鱼肉品种的高通量快速检测方法。该方法特异性好、灵敏、通量高,可同时准确鉴别8种鱼成分,检测灵敏度均可达0.1 ng/μL,且结果肉眼可见。该方法在鱼肉及其制品掺假现场快速筛查方面具有较大应用潜力。