这项工作得到了以色列农业部首席科学家 (#16-16-0003) 的赠款的支持, 得到了以色列国科学、技术和 Spaceand。

1. 植物材料和生长条件
<ol><li>种子一烟草 (品种萨姆松) 种子每 5 cm x 5 cm 罐充满标准罐培养基。把花盆放在托盘上。在长日条件下的生长室中种植植物 (16/8 小时光/暗) 在恒温23摄氏度。用自来水灌溉, 直到水从锅里排水。</li>
	<li>50±5天后, 根据适宜的试验浓度, 开始在灌溉中进行铁处理。例如, 我们使用了一系列的铁浓度从0到6毫米, 辅以可溶性铁离子螯合剂 (fe EDDHA)。每两天用适当的溶液灌溉植物 (以避免脱水) 6-8 天。</li>
</ol>2. 准备用于铁测量的叶子
注: 所有要使用的材料必须是无铁的, 以减少铁污染的风险.用 4% HCl 溶液清洗砂浆和杵两次, 每次使用前用过滤纸干燥。如果任何材料被重用, 用 4% HCl 溶液清洗两次, 用滤纸干燥。
<ol><li>使用手套 (不要使用任何金属设备) 用手将叶子从茎上分离出来。每个样品使用约10克的叶子 (新鲜重量)。使用喷雾瓶清洁每片叶片的双蒸馏水 (DDW)。这一步骤对于避免铁污染是很重要的。</li>
	<li>把纸巾上的叶子晒干, 放进纸袋里。将纸袋转移到烤箱, 在恒温80摄氏度2-3 天。</li>
	<li>干燥时, 用砂浆和杵将叶子粉碎, 转到无菌的15毫升塑料管。</li>
</ol>3. 把树叶烧成灰烬
注: 使用低 pH 值 (接近 0) 的盐酸溶液的目的是提高铁的溶解度。岩石羊毛用于防止气体在燃烧过程中逃逸。
<ol><li>称一个新的, 密封的20毫升闪烁瓶没有它的盖子。使用 "包装" 按钮记下该值或将值设置为零。将粉碎干燥的叶子 (样品) 添加到瓶子里。</li>
	<li>权衡样品和容器并记下值。用岩石羊毛把瓶子关上。</li>
	<li>在不添加样品的情况下重3瓶, 并记下它们的值。这些小瓶将被用来作为控制, 以评估岩石羊毛的数量, 可能导致任何增加样品重量。</li>
	<li>将样品和控制瓶放在炉子里, 用以下温度步骤开始燃烧: 室温, 快速增加到425摄氏度, 最后, 425°C 4 小时。到了这个时候, 干树叶就会变成灰烬。</li>
	<li>让样品冷却到约100摄氏度, 但不低于这个温度以下两个步骤, 以避免湿度, 这可能会影响到样品的最终重量。使用重型手套, 从炉内取出带镊子的样品, 拿着瓶子 exteriorly。</li>
	<li>把瓶子放在平坦的表面上, 取下岩石羊毛, 用原来的盖子把瓶子关上。</li>
	<li>称3控制瓶 (见 3.3) 并计算其平均重量增益。如果重量增益等于或高于1% 的灰分重量 (见步骤 4.2), 请使用此值作为测量误差的估计。</li>
</ol>4. 为铁的测量准备灰烬
注: 在初始样品中的最终铁浓度计算为灰烬的重量除以盐酸的增加量。
<ol><li>在1米 hcl 溶液 (4% hcl) 中加入12.5 毫升的 37% hcl 溶液, 以87.5 毫升的 DDW (在塑料或玻璃瓶)。</li>
	<li>重量15毫升塑料管, 并记下值或设置值为零使用 "包装" 按钮。把骨灰转移到管子上, 权衡, 并记下值。这是灰的重量。</li>
	<li>在灰烬中加入5毫升的1米 HCl。过滤灰烬通过一个22µm 过滤器, 并添加一个额外的5毫升1米 HCl 通过同一过滤器。</li>
	<li>最后的音量应该是10毫升。请注意, 该解决方案的一部分将在筛选器中丢失。 注: 样品现在可以用火焰原子吸收光谱法或普鲁士蓝方法进行 Fe 测量。</li>
	<li>用原子吸收光谱法和普鲁士蓝方法 (见图 4) 测定每种植物的铁浓度, 制作一个标定曲线。随后, 仅用普鲁士蓝法测量铁浓度。</li>
</ol>5. 火焰原子吸收光谱法测定铁浓度
<ol><li>用火焰原子吸收光谱法从每个样品中去除4毫升。</li>
	<li>将火焰原子吸收光谱法测量所得的结果除以灰烬的重量。将结果值除以 0.01 (因为骨灰在10毫升可溶性)。产生的值是每克灰分 (ppm) 的铁浓度。</li>
</ol>6. 准备普鲁士蓝染色液
<ol><li>通过添加4克4Fe (CN)6到100毫升 DDW 和涡旋 (其他体积和/或浓度可用于不同的要求), 准备4% 普鲁士蓝溶液。应该指出的是, 在这项研究中, 使用了比以前报告 (20%)14更少浓缩的普鲁士蓝溶液。</li>
	<li>保持在黑暗中的解决方案在4°c, 直到使用。该解决方案是稳定的6月时, 储存在这样的条件。</li>
</ol>7. 使用火焰原子吸收光谱法生成普鲁士蓝方法的校准曲线
注: 用以下公式计算灰烬中铁的浓度 <img alt="Equation" src="/files/ftp_upload/57408/57408eq1.jpg">等式1 C: 浓度, V: 样品体积, W: 灰分重量 (g)。
<ol><li>混合0.50 毫升普鲁士蓝溶液和0.50 毫升1米 HCl。这将作为空白解决方案。</li>
	<li>混合0.5 毫升的样品 (骨灰在 4% HCl, 如3节所述) 和0.5 毫升普鲁士蓝溶液 (步骤 6.1) 由吹打。至少等待1分钟, 但不超过5分钟。5分钟后, 样品中的沉淀会发生。</li>
	<li>使用分光光度计将混合体转移到试管并测量 715 nm 的 OD。记下该值。</li>
	<li>将 OD 值 (步骤 7.3) 除以样品的灰重 (步骤 3.2)。结果表示每克灰的 OD。</li>
	<li>绘制从火焰原子吸收光谱测量 (Y 轴) 和 OD 值 (X 轴) 获得的铁浓度之间的线性回归。使用步骤5.2 和7.4 中获得的结果。计算回归公式, y = a +, y 代表铁浓度, a 代表吸光度相交, b 代表吸光度斜率, X 代表 OD。</li>
</ol>8. 使用普鲁士蓝法测定同一植物类型的其他样品中的铁含量
注: 由于这种类型的植物已经建立了校准曲线, 所以从同一植物类型的任何新样品中的铁浓度都可以用线性回归公式直接计算出来。
<ol><li>执行3和4节中的步骤, 后跟步骤7.1 到7.4。</li>
	<li>用线性回归 (步骤 7.5) 得到的公式计算溶液中铁的浓度。</li>
</ol>

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作者没有什么可透露的。

植物组织中铁的测量对于评价灌溉或其他环境条件的影响非常重要。在这里, 我们描述了一个简单和准确的比色法测定烟叶中的铁含量, 可以很容易地适应其他植物种类和组织。
在优化比色法的条件下, 我们用低 ph 介质 (ph < 1.0) 来允许铁的溶解度。燃烧过程的执行, 以释放所有形式的铁, 并确保不存在的污染物在样品将修改结果。关于铁污染, 人们应该记住, 6.7% 的地壳包括氧化...

铁 (Fe) 是所有生物中重要的微量营养素。在植物中, 它是一种必需的微量营养素1 , 因为它参与了基本的过程, 如呼吸, 光合作用和叶绿素生物合成。由于反应导致释放自由基导致氧化应激, 游离铁离子的高积累对植物细胞有害。为了维持植物细胞内的铁稳态, 离子储存在 ferritins 内, 直接参与铁稳态2的蛋白质笼和所有生物体中铁的主要贮存结构。同时, 缺铁性贫血会影响到人口的很大比例, 从而增加了对植物铁生物强化的需求。由于植物铁蛋白的独特特性, 用铁蛋白进行食品浓缩, 为解决营养不良3的问题提供了一个有前景的战略。
铁离子主要见于两种氧化状态, 即黑色金属 (价 fe2 +或铁 (II)) 和铁 (三价 fe3 +或铁 (III)) 的形式。在细胞中也发现了其他几种形式的铁, 如铁簇4。Fe 在细胞之内被存放作为氧化铁并且自然地形成 hematites (fe2O3) 和 ferryhidrites (fe3 +)2O3· 0.5H2o) 在生理情况下5。在这些反应中形成的氢氧化物, 特别是铁形态, 具有很低的溶解度。铁的保留因此受到溶液 ph 值的影响, 并且在很大程度上是在 ph 值 56以上的固态状态。
考虑到铁的溶解度低、反应性高, 其在植物组织和器官中的转移必须与合适的螯合分子相联系。此外, 它的氧化还原状态之间的铁和铁形式1必须控制。在叶内, 约80% 的铁是在光合细胞中发现的, 由于其在电子运输系统中的重要作用, 在生物合成细胞色素, 叶绿素和其他血红素分子, 以及在形成铁 S 簇7。在细胞内铁过量的情况下, 剩余移位进入液泡中, 金属在铁蛋白分子中储存8。
在植物组织中, 铁可以用几种方法来测量, 包括火焰原子吸收光谱9 (原子吸收光谱法) 或比色测定10, 前者比后者精确得多。火焰原子吸收光谱法是一种高度精确的技术, 使人们能够根据单个元素的电磁辐射来确定样品的元素组成。火焰原子吸收光谱法将金属离子转化为原子态, 通过样品的加热, 导致离子激发和特定波长的发射, 当给定离子返回其基态时。不同离子的排放由单色仪分离, 并通过吸收传感器11进行检测。火焰原子吸收光谱因而服务直接地定量铁浓度。然而, 在生物组织中可视化铁的其他技术是可用的。电感耦合等离子体质谱 (ICP)12是一种非常精确的测量铁和其他微量元素的技术, 但对于火焰原子吸收光谱和 ICP-ms 的设备缺乏是一个普遍的问题。另一方面, 硫氰酸盐比色法测定铁量13缺乏精度, 无法检测样品之间的细微变化。普鲁士蓝染色14、15、16、17是基于铁离子盐 (K4Fe (CN)6) 反应的间接方法, 产生了强蓝色, 用于动物和植物组织组织学切片中的定性铁检测。
金属 (零价) 铁在岩石圈中是罕见的。环境中铁的主要非复合离子形式主要由环境中的氧量决定, 铁在缺氧环境中相对丰富, 铁在有氧场所占主导地位。后一种形态在极酸性环境中也占主导地位, 但在缺氧和酸性环境下, 铁氧化的致病剂往往不同于18。当铁在 4% HCl (pH 0) 在一个有氧环境中可溶性时, 稀释铁的主要部分存在作为铁形式 (Fe3 +)19,20。
铁离子与 K4Fe (CN)6的反应如下:
Fe3 +: FeCl3 + K4Fe (cn)6 = KFe (III) Fe (cn)6¯ + 3KCl
Fe2 +: 4 FeCl2 + 2 K4Fe (cn) 6 = fe4(Fe (CN)6)2 + 8 氯化钾
在本研究中, 我们询问普鲁士蓝染色是否有助于测定溶液中的铁含量。
初步验证了水溶液中铁浓度与普鲁士蓝染色的相关性。Fe (作为 FeCl2, FeCl3或1:1 混合物的二) 集中在水溶液由原子吸收光谱和吸收 (OD) 在普鲁士人的蓝色的加法以后测量。图 1显示了每个方法获得的测量的线性回归曲线。结果表明, 普鲁士蓝法可用于定量分析溶液中铁的浓度。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57408/57408fig1.jpg"> 图 1: 用火焰原子吸收光谱法测定的铁浓度与由普鲁士蓝方法获得的光吸收 (OD, 715 nm) 之间的线性回归.蓝色正方形和线代表 fe2 +解答, 红色正方形和线代表 fe3 +解答, 并且黑正方形和线代表1:1 混合物在 fe2 +和 fe3 +之间。得到了以下回归: [Fe2 +] = 3 + 123 x OD, r = 0.996, r2 = 0.989;[Fe3 +] = 1 + 292 x OD, r = 0.999, r2 = 0.997;和 [Fe2 +/3 +] = 11 + 146 x OD, r = 0.983, r2 = 0.956。fe2 +捐赠者是 FeCl2和 fe3 +捐赠者是 FeCl3。<a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/57408/57408fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
为了适应比色普鲁士蓝法对植物组织进行定量分析, 用火焰原子吸收光谱和普鲁士蓝染色测定烟叶灰分的铁含量。这两种技术的结果有很好的相关性。

<table><tbody><tr><td>Potassium Hexacyanoferrate(II)</td><td>Fisher Chemical</td><td>14459-95-1</td><td>Reagent for the Pussian Blue</td></tr><tr><td>Millex Syringe Filter Unit, Vial Vent 0.22 &amp;mu;m</td><td>Millec</td><td>SLGP033RS</td><td>Filter used to filter the ashes + 4% HCl Solution</td></tr><tr><td>Scintillation Vials</td><td>Fisherbrand</td><td>03-337-4</td><td>Used to keep the dry powdered plant material during the burning procedure.</td></tr><tr><td>Disposable Syringe 10 ml</td><td>Medi-Plus</td><td>1931</td><td>Syringe used during the filtration</td></tr><tr><td>Hydrochloric acid</td><td>Sigma-Aldrich</td><td>231-595-7</td><td>Used in the 4% HCl solution to dilute the ashes and clean the materials</td></tr><tr><td>&lt;em&gt;Tobacco, Nicotiana tabacum&lt;/em&gt; cv. Samsun NN</td><td>Obtained from Prof. Simon Barak and routinely used in the Zaccai Lab</td><td>Barak S, Nejidat A, Heimer Y, Volokita M. Transcriptional and posttranscriptional regulation of the glycolate oxidase gene in tobacco seedlings. Plant Molecular Biology. 2001 Mar 1;45(4):399-407.</td><td>Tobacco cultivar used in this protocol</td></tr><tr><td>Glass Wool (Rock Wool)</td><td>Sigma-Aldrich</td><td>659997-17-3</td><td>Used in the procedure of burning samples in the furnace.</td></tr></tbody></table>

a colorimetric method for measuring iron content in plants

铁是生物体中最重要的微量营养素之一, 涉及呼吸和光合作用等基本过程。在所有生物体中, 铁含量相当低, 相当于植物的约0.009% 的干重。迄今为止, 测定植物组织中铁浓度的最准确方法之一是火焰吸收原子吸收光谱法。然而, 这种方法耗时且昂贵, 需要在工厂实验室中不常见的特定设备。因此, 需要一个简单而准确的方法, 可以经常使用。在动物和植物组织学切片中, 经常使用比色普鲁士蓝法进行定性铁染色。本研究采用普鲁士蓝法对烟叶中铁进行定量测定。我们验证了这种方法的准确性, 利用原子吸收光谱和普鲁士蓝染色测量相同样品中的铁含量, 并发现两个程序之间的线性回归 (R2 = 0.988)。我们的结论是, 普鲁士蓝法的定量铁测量在植物组织是准确的, 简单的, 廉价的。然而, 在这里提出的线性回归可能不适合其他植物物种, 由于潜在的相互作用的样品和试剂。因此, 需要为不同的植物物种建立一个回归曲线。

当该协议正确执行时, 应在普鲁士蓝和原子光谱学方法取得的结果之间取得良好的相关性。因此, 普鲁士蓝法可以很容易地用于获得准确测量的铁浓度在植物样品, 如以下实验所示。
烟草植物生长如议定书所述, 并灌溉水含有不同的铁浓度 (0, 1, 2, 3, 4, 5, 或6毫米) 超过7天。这些植物在80摄氏度时被收割、清洁和晒干3天。按照所述...

Watch this Scientific Journal Video about A Colorimetric Method for Measuring Iron Content in Plants at JoVE.com

A Colorimetric Method for Measuring Iron Content in Plants

测定植物铁含量的比色法

我们提出了一个简单可靠的协议, 以测量植物组织中的铁含量使用比色普鲁士蓝法。

Iron, one of the most important micronutrients in living organisms, is involved in basic processes, such as respiration and photosynthesis. Iron content ...

a-colorimetric-method-for-measuring-iron-content-in-plants

Universidad de Cartagena UDEC

Research

JoVE Journal

Biochemistry

21.9K 次观看.  Ben-Gurion University of the Negev. 我们提出了一个简单可靠的协议, 以测量植物组织中的铁含量使用比色普鲁士蓝法。

视频: A Colorimetric Method for Measuring Iron Content in Plants

RGB and Spectral Root Imaging for Plant Phenotyping and Physiological Research: Experimental Setup and Imaging Protocols

Better understanding of plant root dynamics is essential to improve resource use efficiency of agricultural systems and increase the resistance of crop cultivars against environmental stresses. An experimental protocol is presented for RGB and hyperspectral imaging of root systems. The approach uses rhizoboxes where plants grow in natural soil over a longer time to observe fully developed root systems. Experimental settings are exemplified for assessing rhizobox plants under water stress and studying the role of roots. An RGB imaging setup is described for cheap and quick quantification of root development over time. Hyperspectral imaging improves root segmentation from the soil background compared to RGB color based thresholding. The particular strength of hyperspectral imaging is the acquisition of chemometric information on the root-soil system for functional understanding. This is demonstrated with high resolution water content mapping. Spectral imaging however is more complex in image acquisition, processing and analysis compared to the RGB approach. A combination of both methods can optimize a comprehensive assessment of the root system. Application examples integrating root and aboveground traits are given for the context of plant phenotyping and plant physiological research. Further improvement of root imaging can be obtained by optimizing RGB image quality with better illumination using different light sources and by extension of image analysis methods to infer on root zone properties from spectral data.

An experimental protocol is presented for assessment of soil grown plant root systems with RGB and hyperspectral imaging. Combination of RGB image time series with chemometric information from hyperspectral scans optimizes insights into plant root dynamics.

RGB 和光谱根成像植物表型和生理研究: 实验装置和成像协议

Better understanding of plant root dynamics is essential to improve resource use efficiency of agricultural systems and increase the resistance of crop ...

科研

环境科学

Quantifying Plant Soluble Protein and Digestible Carbohydrate Content, Using Corn (Zea mays) As an Exemplar

Elemental data are commonly used to infer plant quality as a resource to herbivores. However, the ubiquity of carbon in biomolecules, the presence of nitrogen-containing plant defensive compounds, and variation in species-specific correlations between nitrogen and plant protein content all limit the accuracy of these inferences. Additionally, research focused on plant and/or herbivore physiology require a level of accuracy that is not achieved using generalized correlations. The methods presented here offer researchers a clear and rapid protocol for directly measuring plant soluble proteins and digestible carbohydrates, the two plant macronutrients most closely tied to animal physiological performance. The protocols combine well characterized colorimetric assays with optimized plant-specific digestion steps to provide precise and reproducible results. Our analyses of different sweet corn tissues show that these assays have the sensitivity to detect variation in plant soluble protein and digestible carbohydrate content across multiple spatial scales. These include between-plant differences across growing regions and plant species or varieties, as well as within-plant differences in tissue type and even positional differences within the same tissue. Combining soluble protein and digestible carbohydrate content with elemental data also has the potential to provide new opportunities in plant biology to connect plant mineral nutrition with plant physiological processes. These analyses also help generate the soluble protein and digestible carbohydrate data needed to study nutritional ecology, plant-herbivore interactions and food-web dynamics, which will in turn enhance physiology and ecological research.

Quantifying Plant Soluble Protein and Digestible Carbohydrate Content, Using Corn Zea mays As an Exemplar

The protocols described herein provide a clear and approachable methodology for measuring soluble protein and digestible (non-structural) carbohydrate content in plant tissues. The ability to quantify these two plant macronutrients has significant implications for advancing the fields of plant physiology, nutritional ecology, plant-herbivore interactions and food-web ecology.

以玉米 (玉蜀黍) 为例量化植物可溶性蛋白和可消化碳水化合物含量

Elemental data are commonly used to infer plant quality as a resource to herbivores. However, the ubiquity of carbon in biomolecules, the presence of ...

Setup of Capillary Electrophoresis-Inductively Coupled Plasma Mass Spectrometry (CE-ICP-MS) for Quantification of Iron Redox Species (Fe(II), Fe(III))

Dyshomeostasis of iron metabolism is accounted in the pathophysiological framework of numerous diseases, including cancer and several neurodegenerative conditions. Excessive iron results in free redox-active Fe(II) and can cause devastating effects within the cell like oxidative stress (OS) and death by lipid peroxidation known as ferroptosis (FPT). Therefore, quantitative measurements of ferrous (Fe(II)) and ferric (Fe(III)) iron rather than total Fe-determination is the key for closer insight into these detrimental processes. Since Fe(II)/(III) determinations can be hampered by fast redox-state shifts and low concentrations in relevant samples, like cerebrospinal fluid (CSF), methods should be available that analyze quickly and provide low limits of quantification (LOQ). Capillary electrophoresis (CE) offers the advantage of fast Fe(II)/Fe(III) separation and works without a stationary phase, which could interfere with the redox balance or cause analyte sticking. CE combined with inductively coupled plasma mass spectrometry (ICP-MS) as a detector offers further improvement of detection sensitivity and selectivity. The presented method uses 20 mM HCl as a background electrolyte and a voltage of +25 kV. Peak shapes and concentration detection limits are improved by conductivity-pH-stacking. For reduction of 56[ArO]+, ICP-MS was operated in the dynamic reaction cell (DRC) mode with NH3 as a reaction gas. The method achieves a limit of detection (LOD) of 3 &#181;g/L. Due to stacking, higher injection volumes were possible without hampering separation but improving LOD. Calibrations related to peak area were linear up to 150 &#181;g/L. Measurement precision was 2.2% (Fe(III)) to 3.5% (Fe(II)). Migration time precision was &#60;3% for both species, determined in 1:2 diluted lysates of human neuroblastoma (SH-SY5Y) cells. Recovery experiments with standard addition revealed accuracy of 97% Fe(III) and 105 % Fe(II). In real-life bio-samples like CSF, migration time can vary according to varying conductivity (i.e., salinity). Thus, peak identification is confirmed by standard addition.

Setup of Capillary Electrophoresis-Inductively Coupled Plasma Mass Spectrometry CE-ICP-MS for Quantification of Iron Redox Species FeII, FeIII

This iron redox speciation method is based on capillary electrophoresis-inductively coupled plasma mass spectrometry with sample stacking combined with short analysis in one run. The method quickly analyzes and provides low limits of quantification for iron redox species across a diverse range of tissues and biofluid samples.

为铁氧化还原物种（Fe（II）、Fe（III）定量设置毛细管电泳-电感耦合等离子体质谱仪（CE-ICP-MS）

Dyshomeostasis of iron metabolism is accounted in the pathophysiological framework of numerous diseases, including cancer and several neurodegenerative ...

化学

<meta charset="utf8"></head><body>用于检测新型铁螯合剂的荧光检测

Quantifiable and Inexpensive Cell-Free Fluorescent Method to Confirm the Ability of Novel Compounds to Chelate Iron

Cancer cells require large amounts of iron to maintain their proliferation. Iron metabolism is considered a hallmark of cancer, making iron a valid target for anti-cancer approaches. The development of novel compounds and the identification of leads for further modification requires that proof of mechanism assays be carried out. There are many assays to evaluate the impact on proliferation; however, the ability to chelate iron is an important and sometimes overlooked end-point measure due to the high costs of equipment and the challenge to quickly and reproducibly quantify the strength of chelation. Here, we describe a quantifiable and inexpensive cell-free fluorescent method to confirm the ability of novel compounds to chelate iron. Our assay relies on the commercially available inexpensive fluorescent dye Calcein, whose fluorescence can be quantified on most fluorescent microtiter plate readers. Calcein is a weak iron chelator, and its fluorescence is quenched when it binds Fe2+/3+; fluorescence is restored when a novel chelator outcompetes Calcein for bound Fe2+/3+. The removal of fluorescent quenching and the resulting increase in fluorescence allows the chelation ability of a novel putative chelator to be determined. Therefore, we offer an inexpensive, high-throughput assay that allows the rapid screening of novel candidate chelator compounds.

<meta charset="utf8"></head><body>作者聚焦:评估新型铁螯合剂对癌细胞代谢的影响

We describe a fluorescent assay that can quickly and inexpensively confirm the ability of novel compounds to chelate iron. The assay measures the ability of compounds to outcompete the iron binding activity of the weak iron chelating fluorescent probe Calcein, resulting in a quantifiable increase in fluorescence when chelation occurs.

可量化且廉价的无细胞荧光方法，用于确认新型化合物螯合铁的能力 

Cancer cells require large amounts of iron to maintain their proliferation. Iron metabolism is considered a hallmark of cancer, making iron a valid target ...

癌症研究

Measurement of Tissue Non-Heme Iron Content using a Bathophenanthroline-Based Colorimetric Assay

Iron is an essential micronutrient. Both iron overload and deficiency are highly detrimental to humans, and tissue iron levels are finely regulated. The use of experimental animal models of iron overload or deficiency has been instrumental to advance knowledge of the mechanisms involved in the systemic and cellular regulation of iron homeostasis. The measurement of total iron levels in animal tissues is commonly performed with atomic absorption spectroscopy or with a colorimetric assay based on the reaction of non-heme iron with a bathophenanthroline reagent. For many years, the colorimetric assay has been used for the measurement of the non-heme iron content in a wide range of animal tissues. Unlike atomic absorption spectroscopy, it excludes the contribution of heme iron derived from hemoglobin contained in red blood cells. Moreover, it does not require sophisticated analytical skills or highly expensive equipment, and can thus be easily implemented in most laboratories. Finally, the colorimetric assay can be either cuvette-based or adapted to a microplate format, allowing higher sample throughput. The present work provides a well-established protocol that is suited for the detection of alterations in tissue iron levels in a variety of experimental animal models of iron overload or iron deficiency.

Here, a protocol for the measurement of the non-heme iron content in animal tissues is provided, using a simple, well-established colorimetric assay that can be easily implemented in most laboratories.

使用基于菲咯啉的比色法测量组织非血红素铁含量

Iron is an essential micronutrient. Both iron overload and deficiency are highly detrimental to humans, and tissue iron levels are finely regulated. The ...

医学

Quantitating Iron Transport Across the Mouse Placenta In Vivo Using Nonradioactive Iron Isotopes

Iron is essential for maternal and fetal health during pregnancy, with approximately 1 g of iron needed in humans to sustain a healthy pregnancy. Fetal iron endowment is entirely dependent on iron transfer across the placenta, and perturbations of this transfer can lead to adverse pregnancy outcomes. In mice, measurement of iron fluxes across the placenta traditionally relied on radioactive iron isotopes, a highly sensitive but burdensome approach. Stable iron isotopes (57Fe and 58Fe) offer a nonradioactive alternative for use in human pregnancy studies.
Under physiological conditions, transferrin-bound iron is the predominant form of iron taken up by the placenta. Thus, 58Fe-transferrin was prepared and injected intravenously in pregnant dams to directly assess placental iron transport and bypass maternal intestinal iron absorption as a confounding variable. Isotopic iron was quantitated in the placenta and mouse embryonic tissues by inductively coupled plasma mass spectrometry (ICP-MS). These methods can also be employed in other animal model systems of physiology or disease to quantify in vivo iron dynamics.

Quantitating Iron Transport Across the Mouse Placenta In Vivo Using Nonradioactive Iron Isotopes

This article demonstrates how to prepare and administer transferrin-bound nonradioactive isotopic iron for studies of iron transport in mouse pregnancy. The approach for quantifying isotopic iron in fetoplacental compartments is also described.

使用非放射性铁同位素定量体内通过小鼠胎盘的铁转运

Iron is essential for maternal and fetal health during pregnancy, with approximately 1 g of iron needed in humans to sustain a healthy pregnancy. Fetal ...

生物学

The Caco-2 Cell Bioassay for Measurement of Food Iron Bioavailability

Knowledge of Fe bioavailability is critical to the assessment of the nutritional quality of Fe in foods. In vivo measurement of Fe bioavailability is limited by cost, throughput, and the caveats inherent to isotopic labeling of the food Fe. Thus, there exists a critical need for an approach that is high-throughput and cost-effective. The Caco-2 cell bioassay was developed to satisfy this need. The Caco-2 cell bioassay for Fe bioavailability utilizes simulated gastric and intestinal digestion coupled with culture of a human intestinal epithelial cell line known as Caco-2. In Caco-2 cells, Fe uptake stimulates the intracellular formation of ferritin, an Fe storage protein easily measured by enzyme-linked immunosorbent assay (ELISA). Ferritin forms in proportion to Fe uptake; thus, by measuring Caco-2 cell ferritin production, one can assess intestinal Fe uptake from simulated food digests into the enterocyte. 
Via this approach, the model replicates the key initial step that determines food Fe bioavailability. Since its inception in 1998, this model approach has been rigorously compared to factors known to influence human Fe bioavailability. Moreover, it has been applied in parallel studies, with three human efficacy studies evaluating Fe biofortified crops. In all cases, the bioassay correctly predicted the relative amounts of Fe bioavailability from the factors, crops, and overall diet. This paper provides detailed methods on Caco-2 cell culture coupled with the in vitro digestion process and cell ferritin ELISA necessary to conduct the Caco-2 cell bioassay for Fe bioavailability.

The Caco-2 cell bioassay for iron (Fe) bioavailability represents a cost-effective and versatile approach to assess Fe bioavailability from foods, food products, supplements, meals, and even diet regimens. Thoroughly validated to human studies, it represents the state of the art for studies of Fe bioavailability.

用于测量食品铁生物利用度的Caco-2细胞生物测定法

Knowledge of Fe bioavailability is critical to the assessment of the nutritional quality of Fe in foods. In vivo measurement of Fe bioavailability is ...

Introduction to Mass Spectrometry

Source: Laboratory of Dr. Khuloud Al-Jamal - King&#39;s College London

Mass spectrometry is an analytical chemistry technique that enables the identification of unknown compounds within a sample, the quantification of known materials, the determination of the structure, and chemical properties of different molecules.
A mass spectrometer is composed of an ionization source, an analyzer,&#160;and a detector. The process involves the ionization of chemical compounds to generate ions. When using inductively coupled plasma (ICP), samples containing elements of interest are introduced into argon plasma as aerosol droplets. The plasma dries the aerosol, dissociates the molecules, and then removes an electron from the components to be detected by the mass spectrometer. Other ionization methods such as electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) are used to analyze biological samples. Following the ionization procedure, ions are separated in the mass spectrometer according to their mass-to-charge ratio (m/z), and the relative abundance of each ion type is measured. Finally, the detector commonly consists in an electron multiplier where the collision of ions with a charged anode leads to a cascade of increasing number of electrons, which can be detected by an electrical circuit connected to a computer.
In this video, the procedure of ICP-MS analysis will be described by the detection of 56Fe as an example.

测定植物铁含量的比色法

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RGB 和光谱根成像植物表型和生理研究: 实验装置和成像协议

以玉米 (玉蜀黍) 为例量化植物可溶性蛋白和可消化碳水化合物含量

为铁氧化还原物种（Fe（II）、Fe（III）定量设置毛细管电泳-电感耦合等离子体质谱仪（CE-ICP-MS）

可量化且廉价的无细胞荧光方法，用于确认新型化合物螯合铁的能力

可量化且廉价的无细胞荧光方法，用于确认新型化合物螯合铁的能力

可量化且廉价的无细胞荧光方法，用于确认新型化合物螯合铁的能力

使用基于菲咯啉的比色法测量组织非血红素铁含量

使用非放射性铁同位素定量体内通过小鼠胎盘的铁转运

用于测量食品铁生物利用度的Caco-2细胞生物测定法

质谱分析法导论