温度对胡子鲶(Clarias fuscus)胚胎和幼鱼发育的影响

鱼类的早期发育对温度的变化十分敏感,尤其是在胚胎阶段和早期仔鱼阶段更为突出,过高或过低的水温往往会导致胚胎发育的畸型或停止发育甚至死亡。因而,研究温度对各种鱼的胚胎和幼鱼发育的影响,是进行鱼类尤其是养殖的经济鱼类的人工繁殖研究所必须进行的重要工作之一。国内外学者:Hayes,F.R.     

低pH对鱼类胚胎发育、鱼苗生长及鳃组织损伤影响的研究

本文研究了低pH水平对鱼类的胚胎,鱼苗和鱼种的影响以及鱼鳃的组织学观察。在硬水环境,pH≤4.5时,对泥鳅胚胎发育有严重影响。胚胎在低pH水平下,发育进程明显地迟缓。pH≤5.5时,泥鳅幼苗的生长受到抑制;在软水环境,pH≤4.5时,影响草鱼苗和幼鱼的存活率。低pH水平加上铝则对鱼类呈现出协同毒性。低pH使鱼鳃直接遭受严重的损害:出现大量的粘液、渗血、鳃上皮肿胀和脱落,组织增生和融合。     

培养基初始pH值对木聚糖酶合成的影响

本文探讨了培养基三种初始ｐＨ值对木聚糖酶合成的影响。试验结果表明,培养基初始ｐＨ值对木聚糖酶的合成有重大影响,低ｐＨ有利于提高木聚糖酶活力。在碳源为７ｇ／Ｌ条件下,初始ｐＨ值为４．０时合成的木聚糖酶活力高达３２．８７ＩＵ／ｍｌ,酶产率和得率分别为６５７４．０ＩＵ／Ｌ·ｄ和４６９５．７ＩＵ／ｇ木聚糖。酶活力和酶产率是初始ＰＨ５．０的１．７倍,分别是初始ＰＨ６．０的３．８倍和２．３倍。进一步研究表明,     

亲本繁殖和胚胎孵化温度对斑马鱼孵化表现的影响

亲本效应(parental effect)指亲代的表现型及其所经历的环境因素而非基因型对子代表现型差异和适应性的影响,对子代适合度的维持与提高具有重要生态学意义。为探究亲本效应对鱼类胚胎发育可塑性的影响,本研究选取卵生鱼类斑马鱼(Danio rerio)为实验对象,采用2×2双因素设计,测定了不同亲本繁殖温度(22、28℃)和不同胚胎孵化温度(22、28℃)及其交互作用对斑马鱼孵化表现(孵化率、胚胎死亡率、初孵仔鱼畸形率、孵化历时、初始孵化时间、结束孵化时间)的影响。结果表明：亲本繁殖和胚胎孵化温度交互作用对斑马鱼胚胎死亡率、初始孵化时间、结束孵化时间、孵化历时等均有显著影响(P<0.05),亲本繁殖与胚胎孵化温度相一致时胚胎的死亡率更低、孵化时间更短;斑马鱼孵化表现受亲本效应(代际发育可塑性)和子代发育环境(代内发育可塑性)的双重影响,亲本效应对早期生活史阶段鱼类表型特征的塑造有重要作用。     

G3基因工程菌发酵中pH值对包涵体型及目的蛋白表达的影响

在不同ｐＨ值条件下摇瓶及罐发酵Ｇ３双体分子重组菌。探讨ｐＨ值对Ｇ３双体分子包涵体形成及目的蛋白表达水平的影响，确定Ｇ３双体分子重组菌发酵最佳ｐＨ值为生长期ｐＨ７．０－＃．２，生产期ｐ６．７－６．８。     

胚胎孵化温度和初孵仔鱼发育温度对斑马鱼仔鱼热适应性的影响

发育可塑性是引起生物新性状产生与多样化的关键因素。在气候变化的背景下,探究鱼类热适应性的发育可塑性,有助于理解早期生活史阶段鱼类热适应表型的进化,具有重要的生态学意义。为探究胚胎孵化温度和初孵仔鱼发育温度对鱼类热适应表型的影响,本研究选取卵生鱼类斑马鱼(Danio rerio)为实验对象,采用2×2双因素研究设计,测定了不同胚胎孵化温度(低温组22℃、高温组28℃)和不同初孵仔鱼发育温度(低温组22℃、高温组28℃)及其交互作用对斑马鱼热偏好(偏好温度)、热回避(冷回避温度、热回避温度)、非回避温度范围以及热耐受(临界低温、临界高温、致死低温、致死高温)的影响。结果表明：胚胎孵化温度和初孵仔鱼发育温度对斑马鱼偏好温度、回避温度、临界温度以及致死温度等均有显著影响(P<0.05),胚胎孵化温度和初孵仔鱼发育温度交互作用对非回避温度范围影响显著(P<0.05);胚胎孵化热环境对早期生活史阶段斑马鱼热适应表型特征的塑造具有重要的调节作用,变动的发育温度环境可能扩展鱼类的适宜温度区间,从而提升其在未来变动气候环境中的存活力。     

赣东北地区鱼类区系的研究

赣东北地区共有鱼类１３５种和亚种,隶属于１０目２２科８０属。其中纯淡水鱼类１２８和亚种,占总数的９４．８％。鲤形目是最主要鱼类群,有９５种和亚种,占纯淡水鱼类的７４．２％。鲤科鱼类最丰富,有８０种和亚种,占纯淡水鱼类的６２．５％。此地区鱼类区系以东亚特有的江河平原鱼类为主要组成成分;此外,既有老第三纪原始类群的后裔种类,又有南亚暖水性类群鱼类,而且全北区冷水性类群鱼类也分布于此。与邻近水系比较,此     

高效氯氰菊酯对斑马鱼胚胎毒性的研究

高效氯氰菊酯是一种Ⅱ型拟除虫菊酯类农药,对鱼类及其它水生生物具有高毒,且在其它食物中也可检测到它的残留,高效氯氰菊酯的残留对人类的健康同样具有不容忽视的影响。为了解高效氯氰菊酯对鱼、对人类的毒性机制,选用0.05、0.1、0.2、0.6、1 mg/L五个梯度浓度的高效氯氰菊酯溶液,对斑马鱼胚胎进行毒性处理,在显微镜下观察其对斑马鱼发育形态变化和孵化率等影响。发现高效氯氰菊酯农药对斑马鱼胚胎有严重的致畸效应,这种致畸性呈现剂量依赖性。使用0.1 mol/L浓度的高效氯氰菊酯农药对斑马鱼胚胎进行处理,进行早期胚胎发育的毒性研究。采用荧光差异双向凝胶电泳(2-D DIGE)-质谱相结合的方法,鉴定出11个差异表达蛋白质。这些蛋白质与细胞骨架、应激反应和新陈代谢有关。这些研究结果为进一步研究高效氯氰菊酯对动物的毒性机制提供了基本信息。     

小鼠早期胚胎在6℃不同贮液中的保存研究

低温能抑制哺乳动物植入前胚胎的代谢和发育，从而可使胚胎在体外进行短期贮存。本文利用三种不同贮存液：Ｗｈｉｔｔｅｎ′ｓ、ＰＢＳ和ＣＭＲＬ－１０６６对小鼠２－和８－细胞胚胎进行贮存研究。结果表明，贮于上述三种贮液中的小鼠２－细胞胚胎，在６℃贮２４小时后，经３７℃培养，成活率分别为４２．８％、０％和０％；贮７２小时后的８－细胞胚胎的成活率分别为４３．３％、２０．０％和０％。还证实，培养液中丙酮酸钠和乳酸钠的存在对小鼠胚胎的体外发育是至关重要的。     

海南鹦哥岭地区的鱼类物种多样性与分布特点

作者分别于2001年和2005年对海南中部鹦哥岭的鱼类进行了实地调查,记录到62种鱼类,其中23种为鹦哥岭地区新记录种.结合文献资料,该地区共记载有淡水鱼类7目20科59属75种(含亚种),占海南岛已知淡水鱼类的70.8%:海南特有种16个,占海南特有淡水鱼类的80.0%.鱼类群落中以山区溪流性小型鱼类为主.鹦哥岭南北两坡(南坡昌化江流域,北坡南渡江流域)共有的鱼类共36属42种,占鹦哥岭纯淡水鱼类总种数的60.0%.但两坡的鱼类组成存在一定差异:昌化江流域以山区溪流性鱼类为主,南渡江流域则较多平原江河性物种.利用多样性指数,得出鹦哥岭鱼类物种多样性最高的是南渡江流域的南开河和昌化江流域万冲河段的支流.鱼类的垂直分布集中在海拔200-600 m的中低海拔水体,海拔600 m以上鱼类稀少,而在900 m以上没有发现鱼类.有关部门近年已在鹦哥岭建立自然保护区,为有效保护珍贵的鱼类资源,按照当地鱼类水平和垂直分布特点划定鱼类重点保护河段是十分必要的.     

Ureotelism is inducible in the neotropical freshwater Hoplias malabaricus (Teleostei, Erythrinidae).

Increased environmental pH decreases ammonia transport through the gills, impairing nitrogenous waste. The consequent toxicity is usually drastic to most fishes. A few species are able to synthesize urea as a way to detoxify plasma ammonia. We studied three teleosts of the family Erythrinidae living in distinct environments, and assumed the biochemical behaviors would be different in spite of their being closely related species. Adult fish collected in the wild were submitted to alkaline water and the urea excretion rate was determined. The specific activity of urea cycle enzymes was determined in liver samples of fish from neutral waters. The studied species Hoplias lacerdae, Hoplerithrynus unitaeniatus, and Hoplias malabaricus are ureogenic. Urea synthesis is not a metabolic way to detoxify ammonia in H. lacerdae and Hoplerithrynus unitaeniatus exposed to an alkaline environment. The plasma ammonia profile of both species showed two distinct biochemical responses. Urea excretion of H. malabaricus was high in alkaline water, and the transition to ureotelism is proposed. The nitrogen excretion rate of H. malabaricus was among the highest values reported and the high urea excretion leads us to include this species as ureotelic in alkaline water.     

The sensitivity and reproducibility of the zebrafish (Danio rerio) embryo test for the screening of waste water quality and for testing the toxicity of chemicals

The sensitivity of the zebrafish embryo test, a test proposed for routine waste water control, was compared with the acute fish toxicity test, in the determination of six types of waste water and ten different chemicals. The waste water was sampled from the following industrial processes: paper and cardboard production, hide tanning, metal galvanisation, carcass treatment and utilisation, and sewage treatment. The chemicals tested were: dimethylacetamide, dimethylsulphoxide, cadmium chloride, cyclohexane, hydroquinone, mercuric chloride, nickel chloride, nonylphenol, resmethrin and sodium nitrite. For many of the test substances, the zebrafish embryo test and the acute fish toxicity test results showed high correlations. However, there were certain environmentally-relevant substances for which the results of the zebrafish embryo test and the acute fish toxicity test differed significantly, up to 10,000-fold (Hg(2+) > 150-fold difference; NO(2)(-) > 300-fold; Cd(2+) > 200-fold; resmethrin > 10,000-fold). For the investigated waste water samples and chemicals, the survival rate of the zebrafish embryos showed high variations between different egg samples, within the range of the EC50 concentration. Subsequently, 5-6 parallel assays were deemed to be the appropriate number necessary for the precise evaluation of the toxicity of the test substances. Also, it was found that the sensitivities of different ontogenetic stages to chemical exposure differed greatly. During the first 12 hours after fertilisation (4-cell stage to the 5-somite stage), the embryos reacted most sensitively to test substance exposure, whereas the later ontogenetic stages showed only slight or no response, indicating that the test is most sensitive during the first 24 hours post-fertilisation.     

Lipid and fatty acid composition during embryo and larval development of puye Galaxias maculatus Jenyns, 1842, obtained from estuarine, freshwater and cultured populations

Galaxias maculatus eggs and larvae obtained from broodfish captured either in an estuarine or a freshwater environment, as well as from cultured broodstock were analysed to compare their lipid and fatty acid profiles. Results showed a lower lipid content in embryos and larvae from estuarine populations than those from fresh water, denoting the influence of environmental conditions. The n-3:n-6 ratio was higher in eggs from estuarine and cultured populations, being in the range of marine fishes, whereas for eggs from freshwater fish was lower and typical of freshwater fishes. The polyunsaturated fatty acids (PUFA), particularly docosahexaenoic acid (22:6n-3) and eicosapentaenoic acid (20:5n-3), were higher in eggs and larvae of broodstock coming from culture or estuarine environments than in those from fresh water. Moreover, these fatty acids markedly increased after hatching in larvae coming from estuarine populations, suggesting the effect of the environment on fatty acid profiles to physiologically prepare the larvae to adapt to higher salinity conditions. Linoleic acid (18:2n-6) content was higher in fresh water fish and its reduction during embryo and larval development was accompanied by a significant increase of arachidonic acid (20:4n-6), which was not observed in embryos or larvae from broodstock fish from estuary or aquaculture origin. Both environment and diet of broodstock fish affected lipid and fatty acid composition of G. maculatus embryo and larvae as well as their changes during development.     

The effect of aluminium in Atlantic salmon (Salmo salar) with special emphasis on alkaline water

Atlantic salmon (Salmo salar) parr were exposed to aluminium under both steady state and non-steady state chemical conditions in alkaline water. Under alkaline (pH 9.5) steady state conditions, approximately 350 microg Al l(-1) (predominantly aluminate, Al(OH)(4)(-)) had no acute toxic effect on the salmon. The fish, however, showed a physiological response after 3 weeks of exposure ( approximately 300% increase in blood glucose concentration, about 30% increase in blood haematocrit, and about 15% decrease in plasma Cl(-) concentration). No increase in toxicity was evident under non-steady state conditions, i.e. lowering Al solubility as pH was lowered from 9.5 to 7.5. The results indicate that the toxicity of the aluminate ion (Al(OH)(4)(-)) is low, and particularly lower than the corresponding toxicity of cationic Al hydroxides. The effects observed in fish exposed to Al-rich water at pH 9.5 were counteracted as Al solubility was decreased by lowering pH to 7.5. This is contrary to previous observations where Al solubility has been lowered by increasing pH from 5.0 to 6.5.     

THE INFLUENCE OF CARBON DIOXIDE ON THE TOXICITY OF UN-IONIZED AMMONIA TO RAINBOW TROUT (SALMO GAIRDNERII RICHARDSON)

The toxicity of solutions of ammonia to fish in different dilution waters showed a variation which was not entirely related to the concentration of the un-ionized ammonia molecule. Evidence is presented which shows that this variation can be attributed to the increase in the concentration of free carbon dioxide at the gill surface, which causes a decrease in both the pH value and the concentration of unionized ammonia present; the extent of the decrease depends on the initial concentration of free carbon dioxide in the bulk of the solution. Quantitative measurements of the relation between the free carbon dioxide concentration of the water and the toxicity of un-ionized ammonia are correlated with a theoretical estimation of the pH value of the water at the gill surface.     

In situ toxicity tests of fishes in acid waters

Toxicity of waters within the North Branch of the Moose River to various life stages of lake trout (Salvelinus namaycush), brook trout (Salvelinus fontinalis), creek chub (Semotilus atromaculatus), and blacknose dace (Rhinichthys atratulus) were examined in situ. Study sites were selected that were expected to range from toxic to favourable water quality. For example, pH varied from 4.25 to 7.17, inorganic monomeric Al ranged from ND (< 0.01 mg/l) to 0.40 mg/l, and Ca, from 0.41 to 4.27 mg/l.Toxicity tests were conducted at times when the life stages would naturally occur in these waters and were continued until a range of mortality was observed at the various sites. These experiments suggested that the extent of the drainage system that is toxic to fish increases during snowmelt and major runoff events. Summer base flow water quality was generally the least toxic.Critical life stages were upon hatching and as early feeding fry. In general, young of the year fish were the most tolerant life stage tested. Yearling and adult fish, however, were very sensitive. Blacknose dace were the most sensitive fish of the four species tested, and brook trout were the most tolerant.Hydrogen ion (H⁺) concentration was the most toxic variable in the majority of tests. Inorganic monomeric Al was the most toxic in several, and the combination of H⁺ and Al seemed to cause increased toxicity in many instances. A three-variable model employing hours of exposure, H⁺ concentration, and inorganic monomeric Al predicted mortality quite well. A simple two-variable model using H⁺ and color was nearly as good (R² from 0.49 to 0.94).Documented differences in toxicity among sites and species agreed with observed patterns of fish distribution. These in situ results indicated that laboratory estimates of safe levels of pH and concentrations of Al can result in mortality of fishes in surface waters subject to acidification.     

THE PHYSIOLOGY OF THE RESPIRATION OF FISHES IN RELATION TO THE HYDROGEN ION CONCENTRATION OF THE MEDIUM

1. The ability of marine fishes to absorb oxygen at low tension from the sea water is more or less dependent upon the hydrogen ion concentration of the water. 2. The ability of fishes to withstand wide variations in the range of hydrogen ion concentration of the sea water can be correlated with their habitats. The fishes that are most resistant to a wide variation in the hydrogen ion concentration are most cosmopolitan in their habitat. Those that are least resistant to a variation in the hydrogen ion concentration are the most restricted in their range of habitat. 3. There is a close correlation between the optimum condition of the sea water for the absorption of oxygen at low tension by the herring (Clupea pallasii), the condition of the sea water to which they react positive and that in which they are found most abundantly. 4. It is suggested that the variation in the ability to absorb oxygen at low tension at a given pH of individuals of a species is dependent upon the alkaline reserve of the blood of the individual fish.     

Three species of fishes from an eutrophic, seasonally alkaline lake are not more tolerant to acute exposure to high pH in the laboratory

A number of different freshwater fish species (perch Perca fluviatilis , roach Rutilus rutilus and rudd Scardinius erythrophthalamus ) from either eutrophic (Slapton Ley, a seasonally alkaline lake) or non-eutrophic waters were compared with respect to their sodium uptake kinetics and tolerance to acute (1 h) exposure to pH 9·5. Further comparisons were made with rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta . The influence of fish size was also investigated in rainbow trout. Exposure to pH 9·5 was found to disrupt sodium balance and inhibit ammonia excretion in all species and sizes of fishes. The origin of fishes did not have a significant effect on the sodium uptake kinetics or the physiological responses to high pH water. The fishes from the eutrophic lake therefore did not appear to have any increased tolerance to acute exposure to alkaline water. In contrast to previous studies there was no inhibition of Na⁺ uptake during exposure to high pH. Indeed in some groups of fish Na⁺ uptake was actually stimulated, as was Na⁺ efflux. These differences are attributed to experimental water composition and interspecific differences in physiology. It was not always possible to size-match fishes of the different species, so rainbow trout were used to assess the effect of body mass (from 2 to 40 g), on Na⁺ uptake kinetics and Na⁺ or ammonia fluxes during alkaline water exposure in rainbow trout. Size had no significant effect on these measurements within this narrow range, which helps validate the comparison between species in this study.     

The sulfide tolerance of milkfish and tilapia in relation to fish kills in farms and natural waters in the Philippines

Fish kills of milkfish Chanos chanos and tilapia Oreochromis spp. now occur frequently in brackish, marine, and freshwater farms (ponds, pens, and cages) in the Philippines. Aquafarms with high organic load, limited water exchange and circulation, no aeration, and high stocking and feeding rates can become oxygen-depleted and allow sulfide from the sediments to appear in the water column and poison free-swimming fish. The sulfide tolerance of 2–5 g milkfish and 5–8 g O. mossambicus was determined in 25-liter aquaria with flow-through sea water (100 ml min-1) at 26–30 °C and sulfide stock solutions pumped in at 1ml min-1. Total sulfide concentrations in the aquaria were measured by the methylene blue method and used in the regression against the probits of % survival. Four experiments showed that the two species have similar sulfide tolerance. In sea water of pH 8–8.5, about 163 ± 68 μM or 5.2 ± 2.2 mg l-1 total sulfide (mean ± 2 se) or 10 μM or 313 μg l-1 H2S was lethal to 50% of the fish in 4–8 h, and 61 ± 3 μM total sulfide or 4 μM H2S in 24–96 h (to convert all sulfide concentrations: 1 μM = 32 μg l-1). Earthen pond bottoms had 0–382 μM total dissolved sulfide (mean ± sd = 54 ± 79 μM, n = 76); a tenth of the samples had >200 μM. The water column may have such sulfide levels under hypoxic or anoxic conditions. To simulate some of the conditions during fish kills, 5–12 g milkfish were exposed to an abrupt increase in sulfide, alone or in combination with progressive respiratory hypoxia and decreasing pH. The tests were done in the same flow-through set-up but with sulfide pumped in at 25 ml min-1. The lethal concentration for 50% of the fish was 197 μM total sulfide or 12 μM H2S at 2 h, but 28–53 μM sulfide allowed fish to survive 6–10 h. Milkfish in aquaria with no aeration nor flow-through sea water died of respiratory hypoxia in 5–8 h when oxygen dropped from 6 to 1 mg l-1. Under respiratory hypoxia with 30–115 μM sulfide, the fish died in 2.5–4 h. Tests with low pH were done by pumping a weak sulfuric acid solution at 25 ml min-1 into aquaria with flow-through sea water such that the pH dropped from 8 to 4 in 5 h. Under these conditions, milkfish died in 7–9 h when the pH was 3.5. When 30–93 μM sulfide was pumped in with the acid, the fish died in 2–6 h when the pH was still 4.5–6.3. Thus, sulfide, hypoxia, and low pH are each toxic to milkfish at particular levels and aggravate each other's toxicity. Aquafarms must be well oxygenated to prevent sulfide toxicity and fish kills. This revised version was published online in July 2006 with corrections to the Cover Date.     

水产养殖用解淀粉芽孢杆菌微胶囊的安全性评价

目的:评价水产养殖用解淀粉芽孢杆菌微胶囊的安全性。方法:参照《GB/T21805-2008化学品藻类生长抑制试验》、《GB/T13266-91水质物质对蚤类(大型蚤)急性毒性测定方法》、《GB/T13267-91水质物质对淡水鱼(斑马鱼)急性毒性测定方法》、《渔药临床试验技术规范》等国家标准及相关法规,观察了解淀粉芽孢杆菌微胶囊对小球藻生长的抑制作用以及对大型蚤、斑马鱼和草鱼的急性毒性,分析了其对养殖水体主要理化因子的影响。结果:解淀粉芽孢杆菌微胶囊在终浓度为0.2～2 000mg/L时对小球藻生长具有促进作用,对小球藻的半数抑制浓度大于2 000mg/L,而且其对大型蚤、斑马鱼和草鱼的半数致死浓度也大于2 000mg/L(或mg/kg体重)。此外,在养殖水体中加入解淀粉芽孢杆菌微胶囊至终浓度为0.2～2 000mg/L后14天内,各浓度组的氨氮含量、硫化物和pH均缓慢下降,仅亚硝酸盐氮含量稍微升高后逐渐缓慢降低,但这些理化因子的变化与解淀粉芽孢杆菌微胶囊的加入量呈负相关关系。结论:解淀粉芽孢杆菌微胶囊实际无毒,对养殖水中氨氮、亚硝酸盐氮、硫化物和pH等理化因子的影响均控制在虾虎鱼仔鱼、黄颡鱼、白斑狗鱼、克氏原螯虾等水产养殖动物的安全浓度范围内,为其在水产养殖中的安全应用提供了重要的科学依据。