This work was funded, in part, by the Great Lakes Fishery Commission and the Annis Water Resources Institute. Use of trade, product, or firm names does not imply endorsement by the U. S. Government. This article is Contribution 1867 of the U. S. Geological Survey Great Lakes Science Center.

1，实验室实验<ol><li>得到的猎物鱼在实验过程中，以被馈送到捕食鱼。优选这些捕食鱼应该被捕获在该领域，冷冻，并储存于约-30℃。考虑商业捕鱼作业的猎物鱼的潜在来源。 </li><li>捕食鱼引入到实验室罐被用于实验。高达15捕食鱼已经被引入每一个870-L罐，和多达30个捕食鱼已经被引入到每一个2380-L罐中之前的研究16,18。 </li><li>适应捕食鱼饮食选择猎物的鱼。一旦适应，捕食鱼应该在开始实验前留在这个饮食1-3个月。 </li><li>抛开捕食鱼类样本通过随机选择从一批猎物鱼10〜20个混合样本。捕食鱼类的复合样品的数量范围可以从3到100，这取决于猎物的大小鱼。每个复合物的样品应该是双层包装，冷冻，并储存于约-30℃。 </li><li>通过在每一个容器的牺牲为30〜50％的鱼开始实验。 <ol><li>安乐死的鱼，混合8克Finquel用45升的水在一个大的塑料容器中，然后将鱼在所述容器与Finquel溶液。 </li><li>一旦安乐死，将所有从一箱中牺牲的鱼放入袋中，然后双击袋，并储存在-30°C，直到处理时间。 </li><li>称量每个剩余在每个水箱中的鱼的，并记录重量;麻醉剂可能会需要进行称量。 </li><li>麻醉的鱼，混合4.6克Finquel用在大型塑料容器45升水中，然后将鱼在所述容器与Finquel溶液。 </li><li>等待几分钟，麻醉称量鱼之前生效。 </li></ol></li><li>在实验中的每一天，解冻的适量的捕食鱼，切鱼捕食成片重约1到5g。称取猎物的鱼的数量被放置在每个坦克，然后放下猎物鱼肉片成每罐允许捕食鱼类约1小时进食。然后将所有吃剩的食物，让食物风干约20分钟，然后权衡吃剩的食物对每个坦克。记录食品的放置在箱中的量和食物残渣每天每罐的量。 注：对于代表的实验中，湖鳟鱼喂尽可能多的食物，因为它们会在每18天一次喂奶期间消耗。然而，捕食鱼，也可以放置在固定的口粮16,19。 </li><li>通过牺牲所有剩余的捕食鱼的各罐的终止实验。安乐死的鱼，混合8克Finquel用45升的水在一个大的塑料容器中，然后将鱼在所述容器与Finquel溶液。记录吨他的重量每个牺牲的鱼。对于可靠的结果，实验必须至少130天至少运行100天最好。将所有从罐鱼成一个包，然后双袋，并储存于约-30℃直到处理时间。 </li></ol> 2，鱼同质化<ol><li>选择一组捕食鱼类和/或捕食鱼类复合材料解冻。使复合材料部分地解冻。每个复合物可能需要0.5到1小时，使之均匀。 </li><li>使用适当大小的搅拌机，均匀每一个复合材料。对每个复合材料，放置样品（从50至100克）的匀浆成清洗，丙酮漂洗，并打成jar。然后盖上罐子，并在约-30℃的储存罐，直到处理的时间。 </li><li>洗用均化鱼的所有设备，并然后适当地用蒸馏水​​和甲醇，样品之间的冲洗。 </li></ol> 3，提取<ol><li>称取20.0克解冻均质鱼组织中的200ml烧杯中。 </li><li>加入约40克硫酸钠，并与刮刀拌匀。 </li><li>添加含有同源30，61，161，和166斯派克在那得到的提取物中20毫微克/毫升的最终浓度是代理秒杀的解决方案。 </li><li>使样品干燥在RT混合的同时，每隔20分钟。 </li><li>使样品达到一致性干砂的，在该点的样品准备用于萃取。 </li><li>成立了索氏抽提装置，配备了一枚500毫升瓶中含有特富龙煮芯片，索氏和冷凝器。 </li><li>干鱼的混合物添加到玻璃套管用粗烧结盘底或纸顶针。 </li><li>加入150毫升50％的己烷和50％二氯甲烷的一种用于样品的烧杯中，并搅拌，同时刮烧杯的侧壁用刮铲。 </li><li>通过索氏并在该溶剂中转移到索氏的顶部与附着在烧瓶中，并允许其周期到烧瓶中。 </li><li>再重复第二次150毫升。 </li><li>将索氏所附加的烧瓶上的加热元件和附加冷凝器。 </li><li>开启加热元件上，并把溶剂以温和的沸腾，然后提取了至少16小时确保冷的水被供给到冷凝器。 </li><li>使溶剂冷却后，检查以查看是否有任何试样瓶中含有水。对于那些含有水的烧瓶中，加入硫酸钠和摇动，直至水被硫酸钠吸收。 </li><li>集中使用氮气样品浓缩或Kaderna丹麦（KD）玻璃安装用热水洗澡的样本。 </li><li>允许样品蒸发至小于2毫升的体积，然后通过使用己烷的小洗涤至样品从用于一个5毫升容量瓶中的玻璃器皿传输带至5毫升的最终体积。 </li><li>转移到一个10毫升的小瓶样品的信息标签。 </li></ol><ol><li>通过添加44克浓硫酸至100g活性硅胶制备酸化的硅胶。 </li><li>添加10克酸化硅胶成含有一个小插件的玻璃棉在底部的小层析柱。 </li><li>经过预清洗柱，用10ml己烷中加入1 ml样品提取液上柱。 </li><li>洗脱的柱用20毫升己烷，并收集在锥形20毫升玻璃试管中。 </li><li>放置在氮蒸发器（N-VAP）装置的玻璃管在氮气流中，并浸入热水中。 </li><li>蒸发至小于1毫升但不至干。 </li><li>从N汽雾装置移除并转移到1-mL容量瓶中，用己烷的小洗涤。 </li><li>转移到1.8毫升进样瓶标有样品信息。 </li><li>秒杀4μL内标入瓶中。示例现在准备用于分析。 </li></ol> 5，肛门ysis的气相色谱 - 质谱联用负化学电离<ol><li>使用标准校准仪器：该标准是在混合物组成的良好分离同源组可用。混合1-5包括几乎所有在Arochlors 1016，1221，1232，1242，1248，1254中发现的同系物，和1260混合1被用作多级校正结构，以及系统的线性度由至少准备确认5校准水平介于2和100纳克/毫升的浓度。混合2-5被用作每个同源单点校准。 </li><li>成立色谱 - 质谱系统在负化学电离模式进行氢作为载气（1毫升/分钟）和甲烷作为反应气体。 </li><li>使用熔融石英毛细管柱（60m×0.25毫米内径）涂覆有DB-XLB，在0.25-μm的膜厚度进行分离。程序烘箱温度为60〜212℃，在25℃/分钟，然后以260℃下以1℃/分钟，然后至280℃，在4℃/分钟，用4分钟的最后保持时间。喷射器和传输线的温度应设定在280℃。注入1〜2微升使用不分流进样模式的样本。 </li><li>分析所有样品和标准使用13 C标记decachlorobiphenyl内标法。 </li><li>通过运行第二个来源的标准和Aroclors 1242和1260上执行初始校准的检查，然后针对多氯联苯同系物与观察到的款项从这个检查过程比较预测值。 </li><li>一旦最初的校准过程已成功完成，完成所有样品的分析。运行一个校验检查每十个样品，使用任何校准混合物从初始校准。 </li></ol>净营养转移效率6。计算<ol><li>计算净营养的传输效率，γ，每个组合Ø使用以下方程f罐和PCB同类物： <img alt="式（1）" fo:content-width="2in" src="/files/ftp_upload/51496/51496eq1.jpg" />其中[印刷电路板f]的是在水箱在实验结束时，捕食鱼的平均PCB同类物浓度，W f是在罐在实验结束时，捕食鱼的平均重量，[PCB I]是在储罐中的捕食鱼在实验开始时的平均PCB同类物浓度，W i是捕食鱼在实验开始时的平均体重，以及PCB同源物的摄取量指的是重量在实验的过程中，PCB同类物摄取，平均来说，每一个湖鳟鱼中的罐中。 </li><li>由猎物鱼的每捕食鱼在水箱杜尔吃过的平均量（重量）的捕食鱼复合乘以PCB同类物的平均浓度计算上述公式中的分母荷兰国际集团的实验的全过程。 </li></ol>

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为γ的最准确的估计，实验者必须能够准确地跟踪食品的两个实验的过程中，放置在每一个容器并在每个罐的食物残渣的量的量。为了实现这一点，实验者必须能够从罐取出所有的食物残渣和准确地确定其重量。除了由捕食鱼实际上吃过的食物的准确的跟踪，γ的精确估计也可能依赖于实验的足够持续时间。鉴于广泛引用的实验室研究专门设计来估计多氯联苯营养转移效率对鱼类从他们的食物从105...

Of all of the factors affecting the rate at which fish accumulate contaminants, the efficiency with which fish retain contaminants from the food that they eat is one of the most important1-3. Risk assessment models have been developed to predict future risks to both people and wildlife eating contaminated fish under various scenarios of environmental contamination, and the reliability of these predictions critically depends on the accuracy of the estimates of the efficiency at which fish retain contaminants from their food4.
The efficiency with which the contaminant in the food ingested by the predator is transported through the gut wall is known as gross trophic transfer efficiency5. A portion of the quantity of the contaminant transported through the gut wall of the predator may eventually be lost through depuration and/or metabolic transformation. The efficiency with which the contaminant in the food ingested by the predator is retained by the predator, including any losses due to elimination and metabolic transformation, is known as net trophic transfer efficiency6.
Gross trophic transfer efficiency of organic contaminants to fish from their prey appears to vary with the contaminant&#8217;s chemical properties, including lipid affiliation as measured by the octanol-water partition coefficient, Kow3,7. According to an empirical relationship developed by Thomann3, gross trophic transfer efficiency is relatively high when log Kow is equal to a value between 5 and 6. Gross trophic transfer efficiency declines exponentially at a rate of 50% per unit of log Kow as log Kow increases from 6 to 10, according to the Thomann3 relationship.
Nevertheless, the gross and net trophic transfer efficiencies of polychlorinated biphenyl (PCB) congeners to fish from their prey do not appear to follow the Thomann3 relationship in most cases. Although the trophic transfer efficiencies of PCB congeners to lake whitefish (Coregonus clupeaformis) from its food followed the relationship proposed by Thomann8, trophic transfer efficiencies of PCB congeners were either just weakly related or not related at all to log Kow for Atlantic salmon (Salmo salar)9, rainbow trout (Oncorhynchus mykiss)10, coho salmon (Oncorhynchus kisutch)11, and northern pike (Esox lucius)11.
The overall goal of this study was to present a laboratory technique for estimating the net trophic transfer efficiencies of PCB congeners to a piscivorous fish from its prey. Lake trout (Salvelinus namaycush) was chosen as the piscivorous fish for our experiment because lake trout are relatively easy to maintain in laboratory tanks. Bloater (Coregonus hoyi) was selected as the prey fish to be fed to the lake trout because bloater is eaten by lake trout in its natural setting12. In addition, we determined whether the net trophic transfer efficiencies for lake trout estimated from our laboratory experiment followed the Thomann3 relationship. We also determined whether the degree of activity by the lake trout had a significant effect on net trophic transfer efficiency (&#947;) of the PCB congeners. Activity by lake trout in the Laurentian Great Lakes is believed to have recently increased because changes in the food webs have caused lake trout to allocate more energy toward searching for food13. Lake trout were forced to exercise in one set of tanks by subjecting these lake trout to relatively high flow rates, whereas the other lake trout were permitted to remain relatively inactive by subjecting them to relatively low flow rates. Finally, the specific details of our laboratory procedure that need to be carefully followed to ensure the highest degree of accuracy in the &#947; estimates and to make the laboratory results applicable to the field are discussed, as well as future directions for research building on our laboratory technique. Net trophic transfer efficiency can be estimated both in the laboratory and in the field, and advantages and disadvantages are associated with both approaches. Accuracy in the estimate of &#947; depends on the accuracy of the estimate of food consumption. The amount of food eaten by fish in the laboratory can be accurately determined when proper protocols are followed, whereas the amount of food eaten by fish in the field is typically estimated via bioenergetics modeling. Use of bioenergetics modeling to derive the amount of food eaten has the potential to introduce a substantial amount of uncertainty into the estimates of food consumption. Fish bioenergetics models have been shown to estimate food consumption with no detectable bias for the case of lake trout14,15, but considerable bias in bioenergetics model estimates of food consumption has been detected for the case of lake whitefish15,16. On the other hand, estimates of net trophic transfer efficiency estimated in the laboratory may not be applicable to the field due to a difference in feeding rates between the laboratory and the field17. Evidence from both the laboratory and the field suggest that feeding rate can influence &#947;14,17.
The methodology used in the present study for estimating &#947; in the laboratory is applicable to situations where the predator fish is fed prey fish, and the amount of prey fish eaten by the predator can be accurately tracked. To accomplish this, the experimenter must weigh all of the food before placement in the tank; and the experimenter must be able to remove all of the uneaten food from the tank, and then weigh the uneaten food. In addition, an adequate suite of mixers and blenders should be available to obtain a sufficient degree of homogenization of the samples of both predator and prey fish. Finally, the gas chromatography &#8211; mass spectrometry instrumentation used to determine the PCB congener concentrations must be capable of detecting and quantifying individual PCB congeners at relatively low concentrations.

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			<td height="21" style="height:21px;width:259px;">870-L fiberglass tanks</td>
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			<td style="width:167px;">Eugenol could also be used as an anesthetic.</td>
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			<td style="width:87px;">Wilmad-Lab Glass</td>
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			<td style="width:119px;">112</td>
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			<td height="35" style="height:35px;width:259px;">Soxhlet extraction glassware (500 mL)</td>
			<td style="width:87px;">Wilmad-Lab Glass</td>
			<td style="width:119px;">&#160;LG-6900-104</td>
			<td></td>
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			<td height="35" style="height:35px;width:259px;">Hexane</td>
			<td style="width:87px;">Burdick &#38; Jackson&#160;</td>
			<td style="width:119px;">Cat. 211-4</td>
			<td></td>
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			<td height="35" style="height:35px;width:259px;">Dichloromethane</td>
			<td style="width:87px;">Burdick &#38; Jackson&#160;</td>
			<td style="width:119px;">Cat. 300-4</td>
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			<td height="21" style="height:21px;width:259px;">Silica gel</td>
			<td style="width:87px;">BDH</td>
			<td style="width:119px;">Cat. BDH9004-1KG</td>
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			<td height="35" style="height:35px;width:259px;">Labl Line 5000 mult-unit extraction heater</td>
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			<td style="width:119px;"></td>
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			<td height="35" style="height:35px;width:259px;">Agilent 5973 GC/MS with chemical ionization</td>
			<td style="width:87px;">Agilent</td>
			<td style="width:119px;">5973N</td>
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			<td height="52" style="height:52px;width:259px;">Internal standard solution&#160;</td>
			<td style="width:87px;">Cambridge Isotope Laboratories</td>
			<td style="width:119px;">EC-1410-1.2</td>
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			<td height="21" style="height:21px;width:259px;">PCB congener calibration standards</td>
			<td style="width:87px;">Accustandard</td>
			<td style="width:119px;">C-CSQ-SET</td>
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			<td height="21" style="height:21px;width:259px;">DB-XLB column (60m x 0.25mm, 0.25 micron)</td>
			<td style="width:87px;">Agilent/ J&#38;W</td>
			<td style="width:119px;">122-1262</td>
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laboratory estimation of net trophic transfer efficiencies of pcb congeners to lake trout (salvelinus namaycush) from its prey

一种技术实验室评估中的多氯联苯（PCB）同系物的净营养转换效率（γ），从它们的猎物肉食性鱼类在此说明。在135天的实验室实验中，我们给bloater（ 白鲑hoyi）已被夹在密歇根湖到湖鳟鱼（ 红点鲑namaycush）保持在八个实验室坦克。 Bloater是一种天然猎物的湖鳟。在四个罐的，相对高的流率被用来确保由湖鳟相对高的活性，而较低的流速在其它四个罐使用时，可以实现很低的湖鳟活性。上的槽由槽的基础上，被记录了食物对试验的每一天吃掉湖鳟鱼的数量。每个湖鳟鱼是在实验的开始和结束称重。处死四至九湖鳟从每八个坦克在实验开始时，所有的10湖鳟残留在每一个池中分别euthan美化版在实验结束。我们确定的75​​多氯联苯同系物在湖鳟浓度在实验开始时，在湖鳟鱼在试验结束，并在bloaters在实验过程中提供给湖红点鲑。基于这些测量，γ计算每75 PCB同系物中的每个8罐。意思是γ计算每个75 PCB同系物的激活和未激活湖鳟鱼。因为该试验重复在8缸，对标准误差平均值γ可估计。结果这种类型的实验都是在风险评估模型有助于预测未来的风险，人类和野生动物在环境污染的各种情景食用受污染的鱼类。

湖鳟鱼呈增长的大量实验过程中，作为初始湖鳟意味着重量介于694至907克而最后的湖鳟意味着权重介于853 1566克（ 表1）。食品135天的实验过程中消耗的湖鳟的平均金额介于641至2649克。由实验期间平均的PCB同源物的浓度在湖鳟增加，平均的PCB同源物浓度范围为0.01至7.14纳克/克（湿重）在实验开始时的平均PCB同源物的浓度从0.03范围到29.31结论实验（ 表2）。整个九月，抓bloat...

Watch this Scientific Journal Video about Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout Salvelinus namaycush from Its Prey at JoVE.com

Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout Salvelinus namaycush from Its Prey

一种技术实验室评估中的多氯联苯（PCB）同系物的净营养转换效率从他们的猎物肉食性鱼类呈现。最大化的实验室结果的适用性领域，食鱼鱼应喂是通常食用的字段猎物鱼。

多氯联苯同系物净营养转移效率湖鳟鱼实验室估计（<em&gt;红点鲑namaycush</em&gt;），从它的猎物

A technique for laboratory estimation of net trophic transfer efficiency (&#947;) of polychlorinated biphenyl (PCB) congeners to piscivorous fish from ...

laboratory-estimation-net-trophic-transfer-efficiencies-pcb-congeners

Research

JoVE Journal

Environment

Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout (Salvelinus namaycush) from Its Prey

10.9K 次观看.  U. S. Geological Survey. 一种技术实验室评估中的多氯联苯（PCB）同系物的净营养转换效率从他们的猎物肉食性鱼类呈现。最大化的实验室结果的适用性领域，食鱼鱼应喂是通常食用的字段猎物鱼。 

视频: Laboratory Estimation of Net Trophic Transfer Efficiencies of PCB Congeners to Lake Trout Salvelinus namaycush from Its Prey

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) loading from lake sediments can account for a substantial portion of the total P load in eutrophic, and some mesotrophic, lakes. Laboratory determination of P release rates from sediment cores is one approach for determining the role of internal P loading and guiding management decisions. Two principal alternatives to experimental determination of sediment P release exist for estimating internal load: in situ measurements of changes in hypolimnetic P over time and P mass balance. The experimental approach using laboratory-based sediment incubations to quantify internal P load is a direct method, making it a valuable tool for lake management and restoration.
Laboratory incubations of sediment cores can help determine the relative importance of internal vs. external P loads, as well as be used to answer a variety of lake management and research questions. We illustrate the use of sediment core incubations to assess the effectiveness of an aluminum sulfate (alum) treatment for reducing sediment P release. Other research questions that can be investigated using this approach include the effects of sediment resuspension and bioturbation on P release.
The approach also has limitations. Assumptions must be made with respect to: extrapolating results from sediment cores to the entire lake; deciding over what time periods to measure nutrient release; and addressing possible core tube artifacts. A comprehensive dissolved oxygen monitoring strategy to assess temporal and spatial redox status in the lake provides greater confidence in annual P loads estimated from sediment core incubations.

Lake eutrophication is a water quality issue worldwide, making the need to identify and control nutrient sources critical. Laboratory determination of phosphorus release rates from sediment cores is a valuable approach for determining the role of internal phosphorus loading and guiding management decisions.

实验室确定的磷通量湖泊沉积物作为内部磷载入一个测量

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) ...

科研

环境科学

A Fish-feeding Laboratory Bioassay to Assess the Antipredatory Activity of Secondary Metabolites from the Tissues of Marine Organisms

Marine chemical ecology is a young discipline, having emerged from the collaboration of natural products chemists and marine ecologists in the 1980s with the goal of examining the ecological functions of secondary metabolites from the tissues of marine organisms. The result has been a progression of protocols that have increasingly refined the ecological relevance of the experimental approach. Here we present the most up-to-date version of a fish-feeding laboratory bioassay that enables investigators to assess the antipredatory activity of secondary metabolites from the tissues of marine organisms. Organic metabolites of all polarities are exhaustively extracted from the tissue of the target organism and reconstituted at natural concentrations in a nutritionally appropriate food matrix. Experimental food pellets are presented to a generalist predator in laboratory feeding assays to assess the antipredatory activity of the extract. The procedure described herein uses the bluehead, Thalassoma bifasciatum, to test the palatability of Caribbean marine invertebrates; however, the design may be readily adapted to other systems. Results obtained using this laboratory assay are an important prelude to field experiments that rely on the feeding responses of a full complement of potential predators. Additionally, this bioassay can be used to direct the isolation of feeding-deterrent metabolites through bioassay-guided fractionation. This feeding bioassay has advanced our understanding of the factors that control the distribution and abundance of marine invertebrates on Caribbean coral reefs and may inform investigations in diverse fields of inquiry, including pharmacology, biotechnology, and evolutionary ecology.

This bioassay employs a model predatory fish to assess the presence of feeding-deterrent metabolites from organic extracts of the tissues of marine organisms at natural concentrations using a nutritionally comparable food matrix.

了鱼喂食实验室生物测定，从海洋生物的组织评估次生代谢产物的Antipredatory活动

Marine chemical ecology is a young discipline, having emerged from the collaboration of natural products chemists and marine ecologists in the 1980s with ...

Automated Gel Size Selection to Improve the Quality of Next-generation Sequencing Libraries Prepared from Environmental Water Samples

Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA libraries are needed for optimal results from next-generation sequencing. Environmental samples such as water may have low quality and quantities of DNA as well as contaminants that co-precipitate with DNA. The mechanical and enzymatic processes involved in extraction and library preparation may further damage the DNA. Gel size selection enables purification and recovery of DNA fragments of a defined size for sequencing applications. Nevertheless, this task is one of the most time-consuming steps in the DNA library preparation workflow. The protocol described here enables complete automation of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments. 
In this study, we describe a high-throughput approach to prepare high quality DNA libraries from freshwater samples that can be applied also to other environmental samples. We used an indirect approach to concentrate bacterial cells from environmental freshwater samples; DNA was extracted using a commercially available DNA extraction kit, and DNA libraries were prepared using a commercial transposon-based protocol. DNA fragments of 500 to 800 bp were gel size selected using Ranger Technology, an automated electrophoresis workstation. Sequencing of the size-selected DNA libraries demonstrated significant improvements to read length and quality of the sequencing reads.

This manuscript describes an automated gel size selection approach for purifying DNA fragments for next-generation sequencing. The Ranger Technology provides complete automation of the entire process of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments allowing for high-throughput and high quality next-generation sequencing libraries.

自动凝胶尺寸选择，以提高下一代测序文库的质量，从环境水样准备

Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA ...

Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

In situ recovery (ISR) is the predominant method of uranium extraction in the United States. During ISR, uranium is leached from an ore body and extracted through ion exchange. The resultant production bleed water (PBW) contains contaminants such as arsenic and other heavy metals. Samples of PBW from an active ISR uranium facility were treated with cupric oxide nanoparticles (CuO-NPs). CuO-NP treatment of PBW reduced priority contaminants, including arsenic, selenium, uranium, and vanadium. Untreated and CuO-NP treated PBW was used as the liquid component of the cell growth media and changes in viability were determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in human embryonic kidney (HEK 293) and human hepatocellular carcinoma (Hep G2) cells. CuO-NP treatment was associated with improved HEK and HEP cell viability. Limitations of this method include dilution of the PBW by growth media components and during osmolality adjustment as well as necessary pH adjustment. This method is limited in its wider context due to dilution effects and changes in the pH of the PBW which is traditionally slightly acidic&#160;however; this method could have a broader use assessing CuO-NP treatment in more neutral waters.

Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

Production bleed water (PBW) was treated with cupric oxide nanoparticles (CuO-NPs) and cellular toxicity was assessed in cultured human cells. The goal of this protocol was to integrate the native environmental sample into a cell culture format assessing the changes in toxicity due to CuO-NP treatment.

去除微量元素的氧化铜纳米粉体制备铀<em&gt;原位</em&gt;恢复泌水及其对细胞活力的影响

In situ recovery (ISR) is the predominant method of uranium extraction in the United States. During ISR, uranium is leached from an ore body and extracted ...

Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling from hydrothermal sources in the Precambrian ocean was oxidized by molecular oxygen [O2] produced by cyanobacteria. The oldest BIFs, deposited prior to the Great Oxidation Event (GOE) at about 2.4 billion years (Gy) ago, could have formed by direct oxidation of Fe(II) by anoxygenic photoferrotrophs under anoxic conditions. As a method for testing the geochemical and mineralogical patterns that develop under different biological scenarios, we designed a 40 cm long vertical flow-through column to simulate an anoxic Fe(II)-rich marine upwelling system representative of an ancient ocean on a lab scale. The cylinder was packed with a porous glass bead matrix to stabilize the geochemical gradients, and liquid samples for iron quantification could be taken throughout the water column. Dissolved oxygen was detected non-invasively via optodes from the outside. Results from biotic experiments that involved upwelling fluxes of Fe(II) from the bottom, a distinct light gradient from top, and cyanobacteria present in the water column, show clear evidence for the formation of Fe(III) mineral precipitates and development of a chemocline between Fe(II) and O2. This column allows us to test hypotheses for the formation of the BIFs by culturing cyanobacteria (and in the future photoferrotrophs) under simulated marine Precambrian conditions. Furthermore we hypothesize that our column concept allows for the simulation of various chemical and physical environments &#8212; including shallow marine or lacustrine sediments.

Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

We simulated a Precambrian ferruginous marine upwelling system in a lab-scale vertical flow-through column. The goal was to understand how geochemical profiles of O2 and Fe(II) evolve as cyanobacteria produce O2. The results show the establishment of a chemocline due to Fe(II) oxidation by photosynthetically produced O2.

一个铁（II）的实验室模拟的前寒武纪富海洋上升流系统探索光合细菌生长

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling ...

Development of Metarhizium anisopliae as a Mycoinsecticide: From Isolation to Field Performance

A major concern when developing commercial mycoinsecticides is the kill speed compared to that of chemical insecticides. Therefore, isolation and screening for the selection of a fast-acting, highly virulent entomopathogenic fungus are important steps. Entomopathogenic fungi, such as Metarhizium, Beauveria, and Nomurea, which act by contact, are better suited than Bacillus thuringiensis or nucleopolyhedrosis virus (NPV), which must be ingested by the insect pest. In the present work, we isolated 68 Metarhizium strains from infected insects using a soil dilution and bait method. The isolates were identified by the amplification and sequencing of the ITS1-5.8S-ITS2 and 26S rDNA region. The most virulent strain of Metarhizium anisopliae was selected based on the median lethal concentration (LC50) and time (LT50) obtained in insect bioassays against III-instar larvae of Helicoverpa armigera. The mass production of spores by the selected strain was carried out with solid-state fermentation (SSF) using rice as a substrate for 14 days. Spores were extracted from the sporulated biomass using 0.1% tween-80, and different formulations of the spores were prepared. Field trials of the formulations for the control of an H. armigera infestation in pigeon peas were carried out by randomized block design. The infestation control levels obtained with oil and aqueous formulations (78.0% and 70.9%, respectively) were better than the 63.4% obtained with chemical pesticide.

Development of Metarhizium anisopliae as a Mycoinsecticide: From Isolation to Field Performance

Here, we report the different stages involved in the knowledge-based development of an effective mycoinsecticide, including the isolation, identification, screening, and selection of the "best-fit" entomopathogenic fungus, Metarhizium anisopliae, for the control of insect pests in agriculture.

的发展<em&gt; Metarhizium anisopliae</em&gt;作为防腐剂：从隔离到现场表现

A major concern when developing commercial mycoinsecticides is the kill speed compared to that of chemical insecticides. Therefore, isolation and ...

Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on fresh products and procedures for residue analysis and product quality evaluation. An airtight fumigation chamber containing fresh fruit and vegetables is first flushed with nitrogen (N2) to establish an ultralow oxygen (ULO) environment followed by injection of NO. The fumigation chamber is then kept at a low temperature of 2 - 5 &#176;C for a specified time period necessary to kill a target pest to complete a fumigation treatment. At the end of a fumigation treatment, the fumigation chamber is flushed with N2 to dilute NO prior to opening the chamber to ambient air to prevent the reaction between NO and O2, which produces NO2 and may damage delicate fresh products. At different times after NO fumigation, NO2 in headspace and nitrate and nitrite in liquid samples were measured as residues. Product quality was evaluated after 2 weeks of post-treatment cold storage to determine effects of NO fumigation on product quality. Keeping&#160;O2 from reacting with NO is critical to NO fumigation and is an important part of the protocols. Measuring NO levels is challenging and a practical solution is provided. Possible protocol modifications are also suggested for measuring NO levels in the fumigation chambers as well as residues. NO fumigation has the potential to be a practical alternative to methyl bromide fumigation for postharvest pest control on fresh and stored products. This publication is intended to assist other researchers in conducting NO fumigation research for postharvest pest control and accelerating the development of NO fumigation for practical applications.

This paper describes nitric oxide (NO) fumigation protocols for postharvest pest control. Fumigation chambers are flushed with nitrogen (N2) to establish ultralow oxygen conditions before NO is injected. At the end, chambers are flushed with N2 to dilute NO before exposing products to ambient air to prevent exposure to NO2.

一氧化氮气体防治害虫实验室熏蒸程序

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on ...

Adherence of Bacteria to Plant Surfaces Measured in the Laboratory

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell counts. Plant materials used include roots, sprouts, leaves, and cut fruits. The methods described are inexpensive, easy, and suitable for small sample sizes. Binding is measured in the laboratory and a variety of incubation media and conditions can be used. The effect of inhibitors can be determined. Situations that promote and inhibit binding can also be assessed. In some cases it is possible to distinguish whether various conditions alter binding primarily due to their effects on the plant or on the bacteria.

An easy method for measuring and characterizing bacterial adhesion to plants, particularly roots and sprouts, is described in this article.

细菌附着在实验室测量的植物表面

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell ...

Ecosystem Fabrication (EcoFAB) Protocols for The Construction of Laboratory Ecosystems Designed to Study Plant-microbe Interactions

Beneficial plant-microbe interactions offer a sustainable biological solution with the potential to boost low-input food and bioenergy production. A better mechanistic understanding of these complex plant-microbe interactions will be crucial to improving plant production as well as performing basic ecological studies investigating plant-soil-microbe interactions. Here, a detailed description for ecosystem fabrication is presented, using widely available 3D printing technologies, to create controlled laboratory habitats (EcoFABs) for mechanistic studies of plant-microbe interactions within specific environmental conditions. Two sizes of EcoFABs are described that are suited for the investigation of microbial interactions with various plant species, including Arabidopsis thaliana, Brachypodium distachyon, and Panicum virgatum. These flow-through devices allow for controlled manipulation and sampling of root microbiomes, root chemistry as well as imaging of root morphology and microbial localization. This protocol includes the details for maintaining sterile conditions inside EcoFABs and mounting independent LED light systems onto EcoFABs. Detailed methods for addition of different forms of media, including soils, sand, and liquid growth media coupled to the characterization of these systems using imaging and metabolomics are described. Together, these systems enable dynamic and detailed investigation of plant and plant-microbial consortia including the manipulation of microbiome composition (including mutants), the monitoring of plant growth, root morphology, exudate composition, and microbial localization under controlled environmental conditions. We anticipate that these detailed protocols will serve as an important starting point for other researchers, ideally helping create standardized experimental systems for investigating plant-microbe interactions.

Ecosystem Fabrication EcoFAB Protocols for The Construction of Laboratory Ecosystems Designed to Study Plant-microbe Interactions

This article describes detailed protocols for ecosystem fabrication of devices (EcoFABs) that enable the studies of plants and plant-microbe interactions in highly controlled laboratory conditions.

用于研究植物-微生物相互作用的实验室生态系统制造 (EcoFAB) 协议

Beneficial plant-microbe interactions offer a sustainable biological solution with the potential to boost low-input food and bioenergy production. A ...

Laboratory and Field Protocol for Estimating Sheet Erosion Rates from Dendrogeomorphology

Sheet erosion is among the crucial drivers of soil degradation. Erosion is controlled by environmental factors and human activities, which often lead to severe environmental impacts. The understanding of sheet erosion is, consequently, a worldwide issue with implications for both environment and economies. However, the knowledge on how erosion evolves in space and time is still limited, as well as its effects on the environment. Below, we explain a new dendrogeomorphological protocol for deriving eroded soil thickness (Ex) by acquiring accurate microtopographic data using both terrestrial laser scanning (TLS) and microtopographic profile gauges. Additionally, standard dendrogeomorphic procedures, dependent on anatomical variations in root rings, are utilized to establish the timing of exposure. Both TLS and microtopographic profile gauges are used to obtain ground surface pro&#64257;les, from which Ex is estimated after the threshold distance (TD) is determined, i.e., the distance between the root and the sediment knickpoint, which allows de&#64257;ning the lowering of the ground surface caused by sheet erosion. For each profile, we measured the height between the topside of the root and a virtual plane tangential to the ground surface. In this way, we intended to avoid small-scale impacts of soil deformation, which may be due to pressures exerted by the root system, or by the arrangement of exposed roots. This may provoke small amounts of soil sedimentation or erosion depending on how they physically affect the surface runoff. We demonstrate that an adequate microtopographic characterization of exposed roots and their associated ground surface is very valuable to obtain accurate erosion rates. This finding could be utilized to develop the best management practices designed to eventually halt or perhaps, at least, lessen soil erosion, so that more sustainable management policies can be put into practice.

Characterizing erosion from dendrogeomorphology has usually focused on accurately finding the starting time of root exposure, by examining macroscopic or cell level changes caused by exposure. Here, we offer a detailed description of different novel techniques to obtain more precise erosion rates from highly accurate microtopographic data.

利用树形地貌估算板材侵蚀速率的实验室和现场协议

Sheet erosion is among the crucial drivers of soil degradation. Erosion is controlled by environmental factors and human activities, which often lead to ...