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1.
Hurler's syndrome: deficiency of a specific beta galactosidase isoenzyme   总被引:10,自引:0,他引:10  
A marked deficiency of a specific thermolabile beta-galactosidase isoenzyme (pH optimum 3 to 5) was found in liver and kidney tissues of five patients with the Hurler's syndrome (types 1 to 3).  相似文献   

2.
在北海道知床半岛周边海域,用小型数据记录器监测细鳞大马哈鱼Oncorhyncus gorbuscha和大马哈鱼O.keta的回归游泳行为,探讨其与环境水温的关系。数据记录间隔时间为1 s,连续记录时间为226 h。于2008年8月至10月期间,在知床沿岸放流了带有数据记录器的洄游途中的大马哈鱼和细鳞大马哈鱼个体(分别为30尾和5尾),分别有13尾、3尾个体被捕获。研究表明:试验个体有一系列的上浮和下沉行为,并且频繁地回到表层水面,垂直移动中的深潜水是对表层高水温和暖流分层水中的一种适温调节行为。因此,尽管表层水温较高,性成熟后的大马哈鱼仍会回到表层水面寻找其产卵场所。  相似文献   

3.
在北海道知床半岛周边海域,用小型数据记录器监测细鳞大马哈鱼Oncorhyncus gorbuscha和大马哈鱼O.keta的回归游泳行为,探讨其与环境水温的关系。数据记录间隔时间为1 s,连续记录时间为226 h。于2008年8月至10月期间,在知床沿岸放流了带有数据记录器的洄游途中的大马哈鱼和细鳞大马哈鱼个体(分别为30尾和5尾),分别有13尾、3尾个体被捕获。研究表明:试验个体有一系列的上浮和下沉行为,并且频繁地回到表层水面,垂直移动中的深潜水是对表层高水温和暖流分层水中的一种适温调节行为。因此,尽管表层水温较高,性成熟后的大马哈鱼仍会回到表层水面寻找其产卵场所。  相似文献   

4.
Rather than benefiting wild fish, industrial aquaculture may contribute to declines in ocean fisheries and ecosystems. Farm salmon are commonly infected with salmon lice (Lepeophtheirus salmonis), which are native ectoparasitic copepods. We show that recurrent louse infestations of wild juvenile pink salmon (Oncorhynchus gorbuscha), all associated with salmon farms, have depressed wild pink salmon populations and placed them on a trajectory toward rapid local extinction. The louse-induced mortality of pink salmon is commonly over 80% and exceeds previous fishing mortality. If outbreaks continue, then local extinction is certain, and a 99% collapse in pink salmon population abundance is expected in four salmon generations. These results suggest that salmon farms can cause parasite outbreaks that erode the capacity of a coastal ecosystem to support wild salmon populations.  相似文献   

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Many salmonids have become at risk of extinction. For teleosts whose eggs cannot be cryopreserved, developing techniques other than egg cryopreservation to save genetic resources is imperative. In this study, spermatogonia from rainbow trout were intraperitoneally transplanted into newly hatched sterile triploid masu salmon. Transplanted trout spermatogonia underwent spermatogenesis and oogenesis in male and female recipients, respectively. At 2 years after transplantation, triploid salmon recipients only produced trout sperm and eggs. With use of these salmon as parents, we successfully produced only donor-derived trout offspring. Thus, by transplanting cryopreserved spermatogonia into sterile xenogeneic recipients, we can generate individuals of a threatened species.  相似文献   

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Polymerization of isocyanopeptides results in the formation of high molecular mass polymers that fold in a proteinlike fashion to give helical strands in which the peptide chains are arranged in beta-sheets. The beta-helical polymers retain their structure in water and unfold in a cooperative process at elevated temperatures. The peptide architecture in these polymers is a different form of the beta-helix motif found in proteins. Unlike their natural counterparts, which contain arrays of large beta-sheets stacked in a helical fashion, the isocyanopeptide polymers have a central helical core that acts as a director for the beta-sheet-like arrangement of the peptide side arms. The helical structure of these isocyanopeptide polymers has the potential to be controlled through tailoring of the side branches and the hydrogen-bonding network present in the beta-sheets.  相似文献   

9.
通过对彩色马蹄莲(Zantedeschia Pink Persuasion)的盆栽萌发试验,发现芽的直径约为0.7 cm或大于0.7 cm,芽高约为0.3 cm或大于0.3 cm时,具有优先萌发的优势,称其为优势芽.芽体高度和直径可以作为判断彩色马蹄莲球茎优劣的一个依据.  相似文献   

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以粉花长寿花茎段为材料,在培养基MS+ BA 1.0 mg/L+ NAA 0.1 mg/L中快速繁育,在1/2 MS+NAA 0.2 mg/L培养基中进行生根培养,获得无菌苗.20 d后在16℃、光周期8 h/d的条件下培养,60 d后花芽诱导率达45%,90 d后达100%;而在22℃、光周期12 h/d和22℃、光周期8 h/d条件下培养,长寿花不形成花芽.将带有花芽的茎段接种在分别添加柠檬黄(0.2 g/L)、葡萄紫(0.2g/L)、苹果绿(25 g/L)和胭脂红(0.4 g/L)的培养基MS+ NAA 0.2 mg/L中,获得4种彩色长寿花“迷你试管花卉”.试验表明:容积为250 mL和500 mL的培养容器观赏时间分别为180 d和300 d.  相似文献   

12.
Propylure, 10-n-propyl-trans-5,9-tridecadienyl acetate, and deet, N,N,-diethyl-m-tolumide, were previously reported as the sex pheromone and a sex pheromone activator, respectively, of the pink bollworm. Neither chemical in three extracts of female moth abdomen tips could be detected by gas-liquid chromatographic analysis. These compounds, alone or in combination, exhibited little or no biological activity in the laboratory or in the field. Hexalure, cis-7-hexadecenyl acetate, a synthetic attractant for pink bollworm males, could not be detected in female moth abdomen tip extracts. The pink bollworm sex pheromone was identified as a mixture of cis,cis and cis,trans isomers of 7,11-hexadecadienyl acetate.  相似文献   

13.
Colonization of new environments should promote rapid speciation as a by-product of adaptation to divergent selective regimes. Although this process of ecological speciation is known to have occurred over millennia or centuries, nothing is known about how quickly reproductive isolation actually evolves when new environments are first colonized. Using DNA microsatellites, population-specific natural tags, and phenotypic variation, we tested for reproductive isolation between two adjacent salmon populations of a common ancestry that colonized divergent reproductive environments (a river and a lake beach). We found evidence for the evolution of reproductive isolation after fewer than 13 generations.  相似文献   

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在分析桃红葡萄酒酒精发酵过程中密度实测数据的基础上,建立了桃红葡萄酒酒精发酵过程密度变化规律的数学模型。当葡萄原料含糖量低于12%酒度要求时,加糖操作可将桃红葡萄酒酒精发酵密度随时间变化的曲线分为2段,用回归分析法分析结果表明,加糖前密度随时间的变化规律可用二次方程描述,加糖后密度随时间的变化规律可用对数方程描述。  相似文献   

16.
本文通过四种不同基质的配比,分别在苗期进行了株高、叶宽、叶长的测定,试验结果表明纯泥炭土能够在石竹苗期,株高、叶宽、叶长都能够促进其生长作用,并且叶色呈现深绿色。从经济角度考虑:温室土40%:珍珠岩20%:腐熟马粪10%:泥炭30%的配比是最经济基质配比。  相似文献   

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Rembold CM 《Science (New York, N.Y.)》2004,305(5683):475; author reply 475
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高温操作及贮存过程中葡萄多酚的稳定性   总被引:1,自引:0,他引:1  
对葡萄籽多酚提取物在高温操作及贮存过程中的稳定性进行了研究。结果表明,25℃时,葡萄多酚在80%的乙醇溶液中可存放5d,在水溶液中可存放3d。高温处理(90℃时超过12h,50℃时超过24h)使葡萄籽提取物的颜色变深,原花青素含量降低,但对总酚含量及DPPH自由基的清除能力影响不大。水不溶性葡萄多酚与水溶性酚类物质在相同的总酚含量下,对DPPH的清除能力无明显差异。  相似文献   

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