| Assays of Polyphenol Oxidase Activity in Walnut Leaf Tissue
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Author:
Date:
2014-08-20
[Abstract] Polyphenol oxidase (PPO) is an enzyme that catalyzes the hydroxylation of monophenols into ortho-diphenols (cresolase activity) and the oxidation of o-diphenols into quinones (catecholase activity) (Figure 1). These quinones spontaneously polymerize to form dark-colored phytomelanins, most often seen in the browning of damaged plant tissue. PPO activity can be easily assayed in crude protein extracts from English walnut (Juglans regia) leaves and from many other plant tissue extracts. PPO activity is most commonly measured by spectrophotometric assay, in which the rate of phytomelanin production is quantified, or by oxygen electrode assay, in which the consumption of oxygen by the enzyme is quantified (Figure 1). Though simpler, the utility of the spectrophotometric ...
[摘要] 多酚氧化酶（PPO）是催化单酚羟基化成邻二酚（甲酚酶活性）和将β-二酚氧化成醌（儿茶酚酶活性）（图1）的酶。这些醌自发聚合形成深色的植物色素，最常见于受损的植物组织的褐变。 PPO活性可以容易地在来自英国胡桃（Juglans regia）叶和来自许多其它植物组织提取物的粗蛋白提取物中测定。 PPO活性最通常通过分光光度测定法测量，其中植物肉豆蔻毒素产生的速率被量化，或通过氧电极测定，其中酶对氧的消耗量化（图1）。尽管更简单，分光光度测定的效用受到从不同酚类底物产生的植物角蛋白的最大吸收的变化的限制。氧电极测定通常被认为是用于测量PPO活性的"金标准"，但是与单酚底物一起实施是更费时和困难的，因为与儿茶酚酶活性相比，甲酚水解酶活性通常相当低。该方案将描述从核桃叶的粗蛋白质提取，分光光度测定法和用于测定PPO活性的氧电极测定法。
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| Preparation of Primary Neurons from Rat Median Preoptic Nucleus (MnPO)
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Author:
Date:
2013-12-05
[Abstract] Studying cell physiology is really important to understand their function and to determine action mechanisms taking place in these cells. Using brain slices can be sometime difficult to directly access to cells like neurons. Even if it more steps are needed to get cultured cells, this type of preparation allow a better access to neurons and provide a good way to study their basal properties. Here we describe a protocol of a short term primary neurons culture from MnPO, allowing to kept neurons in good condition to perform electrophysiological recordings.
[摘要] 研究细胞生理学对于了解其功能和确定在这些细胞中发生的作用机制是非常重要的。 使用脑切片可能有时难以直接访问像神经元这样的细胞。 即使需要更多的步骤来培养细胞，这种类型的制剂可以更好地接近神经元，并提供研究其基础性质的好方法。 在这里，我们描述了一种来自MnPO的短期原代神经元培养的方案，允许神经元保持良好的状态进行电生理记录。
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