几种鱼类染色体制备方法的比较

[目的]确定在不同情况下制备鱼类染色体的最佳策略和方法。[方法]分别取黄姑鱼幼鱼尾鳍条、波纹唇鱼再生鳍条、暗纹东方鲀前肾组织以不同的处理方法制备染色体,观察染色体形态并统计细胞分裂指数。[结果]所选用的制片方法都能够获得形态好并且图像清晰的细胞分裂相;分裂指数存在一定的差异:前肾组织细胞分裂指数最高,为2.45%,直接选取的鳍条最低,为1.06%;以肾组织为材料冷滴片和热滴片所得到的染色体质量也不同,冷滴片效果优于热滴片。[结论]结果为在不同研究目的下选取鱼类染色体制备策略提供了参考资料。     

长牡蛎蛋白双酶水解工艺及其产物的抗氧化活性

使用中性蛋白酶和胰蛋白酶双酶水解长牡蛎(Crasostrea gigas)蛋白,采用单因素试验分析了水解时间、pH和酶用量比对水解度的影响,并在此基础上设计正交试验优化酶解的工艺条件,并测定了酶解产物的还原能力和对DPPH自由基的清除能力.结果表明,中性蛋白酶和胰蛋白酶双酶水解牡蛎蛋白的最佳工艺条件为酶解时间3h、pH 7、U中性蛋白酶∶U 胰蛋白酶=1∶3,此时水解度为27.09％;酶解产物具一定的还原能力并对DPPH自由基有较强的清除作用.     

鱼胶在干红葡萄酒中的下胶效果研究

[目的]了解国产东易鱼胶(DOEST)在干红葡萄酒中的下胶效果。[方法]以2011年烟台产区赤霞珠、蛇龙珠、梅鹿特干红原酒为试样,首先以透光率、澄清度及热稳定性为依据确定鱼胶在干红葡萄酒中适宜的下胶浓度,然后再与明胶、蛋清、皂土进行下胶效果的综合比较。[结果]东易鱼胶(DOEST)在干红葡萄酒中使用浓度在40～60 mg/L时可获得令人满意的澄清效果,下胶综合效果可与蛋清相近,优于明胶和皂土。[结论]研究为国产东易鱼胶(DOEST)在干红葡萄酒下胶中的应用提供了参考。     

鲫鱼鱼鳞胶原蛋白提取工艺的研究

以鲫鱼鱼鳞作为原料,采用不同浓度的盐酸作为脱钙溶液,以0.5 mol/L乙酸-乙酸钠缓冲溶液提取其胶原蛋白。单因素分析与正交试验结果表明:提取温度为12℃时,最佳提取条件为固液比1∶25,提取时间每次2 d,脱钙酸浓度为0.4 mol/L,脱钙时间3 h,胶原蛋白提取率为1.142%。     

蛋壳膜的成分及蛋膜化妆品的制作

鸡蛋壳内蛋白膜又称"凤凰衣",由与人体皮肤蛋白性质相近的角蛋白和胶原蛋白组成,是制作化妆品的良好原料。分析表明,蛋白膜中含80.07%蛋白质、18种氨基酸。研究确定了蛋膜化妆品基本原料组成;通过正交试验得到蛋膜化妆品较好的工艺及配方。结果是:最佳保持皮肤湿度化妆品制法及原料为:蛋膜液添加量2.1%,W/O/W乳化、蜂蜡为封闭剂、聚乙烯吡咯烷酮为吸湿剂;最佳吸湿、保湿性化妆品原料与前者相一致,但是乳化类型不同,采用W/O型乳化更好。蛋膜化妆品的皮肤保湿度与市售同类产品进行比较,性能居中等水平。     

玉米胚芽蛋白酶解工艺条件优化研究

选用木瓜蛋白酶对玉米胚芽蛋白进行酶解,探讨木瓜蛋白酶添加量、水解温度、水解时间和pH等单因素对玉米胚芽蛋白水解物水解度的影响,通过单因素试验的结果进行四元二次回归正交旋转组合设计实验,并采用SAS软件对实验结果进行处理分析。经过优化,最终确定木瓜蛋白酶水解玉米胚芽蛋白的最佳工艺条件为:木瓜蛋白酶添加量2.1%,水解温度60℃,水解时间3 h,pH 6.4,在此条件进行验证,实际水解度为13.52%。     

Aggravating factors in the development of ocular abnormalities in farmed Atlantic halibut (Hippoglossus hippoglossus)

Cystic lesions in the eyes of farmed halibut with a number of ocular sequelae have been reported previously with evidence that the condition can be associated with increased activity of choroidal carbonic anhydrase and elevated oxygen tension in the aqueous humour of affected fish. These changes may be compared to the 'bends' in human divers which are characterized by elevated circulating levels of nitrogen together with aggravating factors such as physical exercise. It is postulated that bubble formation and subsequent development of cysts in halibut require not only high aqueous humour oxygen tension but also the imposition of factors such as handling or intraspecific aggression which lead to bubble formation. A significantly higher incidence of lesions was noted in fish handled, weighed and measured every two weeks compared with a control group of unhandled fish, suggesting that physical activity associated with handled and possibly also intraspecific aggression is a factor in generation of ocular lesions in these fish.     

Conditions for the induction of some selective enzymes from <Emphasis Type="Italic">Bacillus subtilis</Emphasis> and their hydrolysis ability against mackerel and gracilar (asparagus, <Emphasis Type="Italic">Gracilaria verrucosa</Emphasis>)

ABSTRACT:   This study was conducted to optimize the cultivation conditions for Bacillus subtilis to produce proteases, amylases and cellulase, and to further investigate the hydrolysis ability against mackerel and asparagus. The extracellular enzymes from B. subtilis after 2 and 4 days incubation in a modified medium, containing 1% skim milk, 1% soya meal, 0.25% starch, 0.25% K₂HPO₄, 0.5% NaCl and 0.05% MgCl₂ were collected for the hydrolysis of asparagus and minced mackerel, respectively. Except for the α,α-diphenyl-β-picrylhydrazyl (DPPH) scavenging ability of the hydrolyzed asparagus, the trolox equivalent antioxidation capacity and DPPH scavenging ability of both samples increased significantly ( P  < 0.05) after 1 h hydrolysis and further increased during elongated hydrolysis at 50°C. Sodium dodecylsulfate–polyacrylamide gel electrophoresis indicated severe degradation of muscle proteins during hydrolysis. Changes in reducing sugar, soluble proteins and peptides before/after hydrolysis suggested the extracellular enzymes from B. subtilis could effectively hydrolyze the mackerel or asparagus, and subsequently improve their antioxidation ability.     

High temporal species turnover enhances the complexity of fish assemblages in Amazonian Terra firme streams

Abstract –  The objective of this study was to quantify fish species diversity in Terra firme streams of the Río Amazonas drainage. Fish diversity was quantified as the number of species collected or species richness in two sites of Yahuarcaca stream, a typical, first order tributary of the central Río Amazonas near Leticia (Colombia). The extremely high species richness recorded, 131 and 133 for the two study sites for a total of 171 species, was primarily due to species of low abundance (rare species) mostly with adults <5 cm in total length. The nonasymptotic tendencies of accumulated species richness over time for the 1999 samples at the two study sites and for the combined samples of 1999, 2001 and 2005 at site 2 suggested that the real number of fish species may be still greater. These findings emphasise the importance of long-term sampling designs to quantify species richness in these systems. Terra firme streams actually sustain greater fish richness than previously reported for similar sized streams that in turn, represent a substantial per cent of the total species richness reported for vast areas of the main stem of Río Amazonas including tributaries and lakes. Terra firme streams should be considered critical hotspots for conservation and management efforts which are urgently needed given the rapid development of ornamental fisheries on small streams throughout Río Amazonas drainage.