这项研究部分得到了美国农业部外国农业服务公司 TASC 的资助。

注: 一氧化氮熏蒸的新鲜产品开始建立在熏蒸室的超低氧条件, 其次是注射 no 和持有熏蒸室在一定的温度, 在特定的治疗期间, 然后是通过冲洗与 N2结束, 以稀释 NO 之前打开熏蒸室如图所示 (图表 3)。对于使用模型 405 nm 没有2/no/氮氧化物监测仪和诺亚一氧化氮分析仪的液体样品在熏蒸室和硝酸盐和亚硝酸盐的头部空间中没有2的测量, 请参考制造商的用户手册详细的操作程序。
注意: 一氧化氮是一种强氧化剂, 会自发地与氧气反应产生二氧化氮。一氧化氮和二氧化氮都是有毒的。请参阅他们的 MSDS 安全处理和使用。为个人安全起见, 应在油烟罩中进行小规模熏蒸试验的所有步骤, 涉及处理和潜在暴露于 no 或 no2 。个人无2报警应用于大规模不进行熏蒸试验。
1. 材料和仪器的准备
<ol><li>
不熏蒸所需的仪器、零件和材料
	<ol>
<li>制造一个有油管出口的铝箔袋。<ol>
<li>用热封口机密封聚四氟乙烯 (PTFE) 管周围的铝箔袋的开口。</li>
			<li>然后用环氧树脂胶封住聚四氟乙烯 (PTFE) 管周围的接缝和接头, 以产生铝箔袋。</li>
			<li>在管子的末端加一个塞。 注: 带油管的铝箔袋不提供商用。但他们可以很容易地在实验室用铝箔袋从商业来源使用热封口机。 注: 氮气: 常规工业氮气在压缩圆筒有纯净≥99.99% 并且是适当的不熏蒸。两个或更多的气缸与调节器可以设置为有不同的出口压力和连接在一起。具有较高出口压力的气缸将首先使用, 然后才会使用较低出口压力的气缸。这将是有用的大型熏蒸测试。</li>
		</ol>
</li>
		<li>密闭熏蒸室。 注: 密是至关重要的没有熏蒸, 因为没有将与 O2泄漏到会议厅的反应。这将减少害虫控制的可用 no, 也不会产生可能损坏新鲜产品的2 。<ol>
<li>玻璃罐: 用凡士林油轻轻涂上盖子的边缘。然后用盖子盖住罐子, 装上有两个插座的物体, 如虫蛀的产品到罐子里。 注: 每个盖子的罐子有两个插座和一个插座有一个塑料管延伸到底部的 jar, 以提高效率的空气置换。</li>
			<li>由高压锅制成的房间: 用凡士林油把房间的边缘涂上油脂。在室内装载产品和昆虫, 用盖子封住。</li>
			<li>大型熏蒸室: 用凡士林油轻轻涂抹垫片。然后在室内装载产品。关门。如有必要, 拧紧夹具以保持密封。 注: 没有气体是高度挥发性的, 所以没有必要有一个风扇在熏蒸室, 以保持空气在会议厅混合。</li>
		</ol>
</li>
	</ol>
</li>
</ol>2. 在熏蒸室中建立 ULO 条件
<ol><li>将一个腔室连接到 N 个2行和一个 O2分析器。 注: 一端的 T 形连接器进入分析仪, 另一端装有 one-way 止回阀, 可用于释放空气, 以避免高流量到 O2分析器。</li>
	<li>通过流量计释放 N2以冲洗燃烧室以除去氧气。</li>
	<li>当 O2级别接近于 30 ppm 时, 将 N2流量降低到 0.5-1 升/分。</li>
</ol>3. 不注入气体
<ol><li>
把不加气的铝箔袋装满。
	<ol>
<li>先用 N2填充袋子, 然后将空气吸出, 从袋子中取出 O2 。</li>
		<li>然后将气体放进烟罩里的袋子里。</li>
		<li>把袋子挂在通风橱里, 不要熏蒸。 注: 长时间使用后, 由于没有2的腐蚀性影响, 该包可能会退化, 油管会变得很脆。所以, 这些袋子需要定期更换。</li>
	</ol>
</li>
	<li>
向熏蒸室注入 NO。
	<ol>
<li>用 N2冲洗注射器和连接的油管, 以刷新 O2。</li>
		<li>从无箔袋中抽取样品, 并将其注入熏蒸室。</li>
		<li>注射后, 冲洗注射器和连接的油管与 N2。</li>
		<li>在熏蒸处理期间, 在2° c 处放置熏蒸室。</li>
	</ol>
</li>
</ol>4. 测量熏蒸室的浓度
注: 虫害控制的熏蒸浓度不得超过 2000 ppm (0.2%) 至 5万 ppm (5%)。此范围是当前无监视器的 "范围之外"。但是, 在稀释样品或使用稀释装置时, 仍不能测量任何水平。
<ol><li>
小室蒸
	<ol>
<li>熏蒸结束时从处理罐中稀释空气样品:<ol>
<li>在 jar 中建立≤30 ppm O2的 ULO 条件。</li>
			<li>从治疗罐中抽取气体样本注入 ULO 罐子。</li>
		</ol>
</li>
		<li>通过烟气监测器将空气循环, 以测量稀释样品中 no 和 no 的2水平。</li>
	</ol>
</li>
	<li>
大房间蒸: 过程在图 4中说明。
	<ol>
<li>建立稀释系统。</li>
		<li>测量 no 和 no2级别。<ol>
<li>打开烟道气体监测器, 用 N2冲洗它。</li>
			<li>打开示例气体流以测量 no 和 no2级别。</li>
			<li>通过关闭样品气体流量来完成测量。</li>
		</ol>
</li>
	</ol>
</li>
</ol>5. 终止无熏蒸
<ol><li>
昆虫熏蒸
	<ol>
<li>将熏蒸室放在通风橱里。</li>
		<li>打开房间</li>
		<li>检索昆虫的死亡率评估。 注: 昆虫通常在一夜之间在环境室内进行熏蒸, 以允许所有活的昆虫在获得死亡率之前恢复。</li>
	</ol>
</li>
	<li>
鲜品熏蒸
	<ol>
<li>将熏蒸室移动到油烟罩 (用于小室)。</li>
		<li>用 N2冲洗熏蒸室以允许特定数量的空气交换。</li>
		<li>在排气口没有监控级别。 注: 烟道气体监测器可用于在 N2冲洗期间监视无级别。通常情况下, 我们冲洗熏蒸室, 以减少没有水平低于 200 ppm 之前, 打开商会的环境空气。</li>
		<li>检索昆虫的死亡率评估 (如果包括昆虫)。</li>
		<li>储存熏蒸产品进行残留分析和后处理质量评估。 注: 允许熏蒸产品在油烟罩中有足够的时间为 no 和 no2消散, 然后再将其移动以进行存储。熏蒸后的产品通常在低温下与冷却器中的控制一起存放一段时间, 然后再评估其质量和可能的损伤。</li>
	</ol>
</li>
</ol>6. 残留分析
<ol><li>
二氧化氮 (无2) 测量使用 405 nm 没有2/no/否X监视器
	<ol>
<li>打开并允许 405 nm 没有2/no/否X监视器预热 20-30 分钟。</li>
		<li>关闭含有该产品的熏蒸室。 注: 熏蒸后, 熏蒸室打开并置于一定温度下, 不允许2消散。在没有测量到2释放的时候, 用带有三通的两个端口的盖子密封密闭室。在过程演示中使用了20° c 的温度。</li>
		<li>将 no2显示器连接到腔室, 以便通过无2监视器来循环空气。</li>
		<li>立即开始在 NO2监视器上记录数据, 并收集1分钟的数据。</li>
		<li>将房间从显示器上断开, 并保持房间密封。 注意: 可以通过2监视器上的菜单 > Dat > 日志, 或者通过计算机上的绘图软件来启动数据记录。</li>
		<li>将密封腔保持在20° c 为1小时, 然后重复数据收集步骤。 注意: 时间间隔可以根据从熏蒸产品中没有2的释放率进行调整。</li>
		<li>计算两个无2浓度之间的差异, 并将数据转换为 mg/千克/小时。</li>
	</ol>
</li>
	<li>
GE (280i 无分析仪测定硝酸盐和亚硝酸盐 注: 有关详细信息, 请参阅制造商手册和杨和柳 (2017) 的纸张21 。<ol>
<li>样品制备<ol>
<li>在搅拌机中质产品样品。</li>
			<li>将15克的匀浆样品从搅拌器转移到一瓶中。</li>
			<li>添加100毫升蒸馏的 H2O 以在瓶中10分钟内解决。</li>
			<li>过滤样品并将过滤后的溶液储存在2° c 直到使用。</li>
		</ol>
</li>
		<li>一氧化氮分析仪用于硝酸根测量的还原剂制备 注: 有关详细信息, 请参阅制造商手册。<ol>
<li>在烧瓶中加入0.8 克氯化钒 (VCl3)。</li>
			<li>慢慢地在烧瓶中加入100毫升的1米盐酸盐 (HCl), VCl3, 瓶盖瓶, 和漩涡几次。</li>
			<li>使用滤纸和漏斗过滤解决方案, 用铝箔密封过滤后的溶液瓶, 并将其存放在冰箱中。</li>
		</ol>
</li>
		<li>硝酸和亚硝酸盐的一氧化氮分析仪测定 注: 有关详细信息, 请参阅制造商手册。<ol>
<li>将水浴预热到95° c。将 4-6 毫升的硝酸还原剂加入到清洗容器中, 并将惰性气体流动率调整到适当的水平。 注: 惰性气体是他。N2气体也可以使用。</li>
			<li>注射5µL 样品溶液, 使用注射器进入清洗容器。</li>
			<li>在样品峰值完成后进行下一次样品注入。</li>
		</ol>
</li>
		<li>一氧化氮分析仪测定亚硝酸根 注: 有关详细信息, 请参阅制造商手册。<ol>
<li>调节清洗容器上的阀门, 使惰性气体有 1-2 psi 压力。</li>
			<li>加入 4-6 毫升浓醋酸, 以填补第一个灯泡的清洗容器。</li>
			<li>重50毫克的碘化钠 (奈), 溶解在 1-2 毫升 H2O。</li>
			<li>在清洗容器中加入奈溶液, 允许混合 1-2 分钟。</li>
			<li>将惰性气体流动率提高到适当的水平。</li>
			<li>注射5µL 样品溶液, 使用注射器进入清洗容器。</li>
			<li>在样品峰值完成后进行下一次样品注射。</li>
		</ol>
</li>
	</ol>
</li>
</ol>7. 果蔬采后质量评价
注: 产品免熏蒸后的伤害会立即出现在熏蒸后 (图 5)。然而, 产品质量通常在经过 1-2 周后的冷藏后进行评估。受伤的症状会随着时间的推移而进步, 在质量评估中可以更好地确定。评估不同新鲜产品的程序可能会有很大差异。在这里, 仅以评估生菜质量的程序为例, 使用已建立的过程5。
<ol><li>熏蒸两周后将生菜从冷藏库中取出。去除包装和检查表面的污渍和变色的所有治疗包括控制。</li>
	<li>根据已建立的程序8, 对所有处理的外部视觉质量进行评分和记录。</li>
	<li>把生菜切成两半, 检查所有的污渍和色的所有处理方法。</li>
	<li>评分并记录所有治疗的内部视觉质量分数。</li>
</ol>

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<li>Haldane, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+red+colour+of+salted+meat%5BTitle%5D)+AND+%22J.+Hyg%22%5BJournal%5D)">The red colour of salted meat.</a> J. Hyg. 1, 115-122 (1901).</li>
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<li>Kader, A. A., Lipton, W. J., Morris, L. L. <a target="_blank" href="http://ucce.ucdavis.edu/files/datastore/234-417.pdf">Systems for scoring quality of harvested lettuce.</a> HortScience. 8, 408-409 (1973).</li>
<li>Liu, Y. -B. <a target="_blank" href="https://www.researchgate.net/publication/270760772_Nitric_oxide_as_a_potent_fumigant_for_postharvest_pest_control">Nitric oxide as a potent fumigant for postharvest pest control.</a> J. Econ. Entomol. 106, 2267-2274 (2013).</li>
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<li>Liu, Y. -B., Yang, X., Simmons, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Efficacy+of+nitric+oxide+fumigation+for+controlling+codling+moth+in+apples%5BTitle%5D)+AND+%22Insects%22%5BJournal%5D)">Efficacy of nitric oxide fumigation for controlling codling moth in apples.</a> Insects. 7, 71(2016).</li>
<li>Manjunatha, G., Lokesh, V., Neelwarne, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nitric+oxide+in+fruit+ripening%3A+trends+and+opportunities%5BTitle%5D)+AND+%22Biotechnol.+Adv%22%5BJournal%5D)">Nitric oxide in fruit ripening: trends and opportunities.</a> Biotechnol. Adv. 28, 489-499 (2010).</li>
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</ol>

将 O2排除在熏蒸室之外, 对于成功地进行虫害控制没有熏蒸是至关重要的。熏蒸室需要有密封的密封和连接线需要冲洗与 N2或其他惰性气体, 以删除 O2之前, 被用于释放没有气体进入熏蒸室。不熏蒸的另一个关键方面是稀释 no, 在熏蒸结束时为 N2冲洗。这可防止生产过量的 NO2及其对新鲜产品的可能伤害。由于不同的新鲜产品具有不同级别的耐受性, 不受2的影响, 因此不进行熏蒸处理可能需要不同级别的 N2冲洗以防止损伤。由于没有2有一个高沸点约21° c, 也与水反应的形式酸, 没有2生产将可能导致增加没有2的熏蒸产品作为残留和增加硝酸盐和/或亚硝酸盐转化从没有2。
要熏蒸的产品类型也可能使熏蒸过程复杂化, 如初始冲洗与 n2以建立 ULO 条件, 最后冲洗与 n2以终止熏蒸处理。大叶蔬菜在穿孔塑料包装, 如包头生菜代表了一个巨大的屏障, 空气流通, 因此, 在开始的时候冲洗 O2与 n2在熏蒸和冲洗没有与 n2的挑战在熏蒸结束。对于这些产品, 最好使用低浓度的组合和更长的处理时间来控制害虫, 因为它对产品质量更安全。
在熏蒸室中监测 no 含量是不进行熏蒸的另一个挑战。大多数仪器不能测量无蒸的高浓度的害虫控制。市面上有少量稀释装置, 但不知道是否适合不熏蒸。然而, 稀释装置可以如上所述, 并用于没有监测使用的气体监测器配备了无传感器。
在熏蒸室中, 可对无浓度监测程序进行更多的修改。例如, 在熏蒸室中的空气样品可以在带有一定体积氮的铝箔袋中稀释。稀释后的空气样本可以通过装有高浓度无传感器的烟气监测器进行循环, 以测量不含浓度。但是, 在过程中要避免氧化 no, 稀释过程可能会造成一些损失。因此, 没有计算的基础上测量的稀释空气样品从熏蒸室将可能低于实际没有水平的熏蒸室。
在熏蒸室中建立 ULO 条件的过程也可以根据可用的熏蒸室类型进行修改。对于可在真空条件下使用的熏蒸室, 可通过反复吸尘的过程建立 ULO 条件, 然后用氮气填充燃烧室。这一过程将更有效地建立 ULO 条件比正常的冲洗过程如上所述。对于存储产品, CO2也可用于代替 N2 , 用于建立不熏蒸的 ULO 条件。
对于残留分析, 405 nm 没有2/no/没有x监视器被选中来测量头部间隙中的熏蒸样本的 no2气体释放, 并设置一氧化氮分析仪检测液体样品中的硝酸盐和亚硝酸盐。然而, 其他类型的仪器有适当的灵敏度和特异性, 用于测量 headspaces 中的 NO2和测定液体样品中的硝酸盐和亚硝酸盐。因此, 可以根据仪器的可用性来修改残留测量的程序。
由于 no 是高度挥发性与沸点的-152 ° c 和立即反应与 O2, 它是不预期的, 没有将继续作为一个残留物熏蒸后的产品熏洗。因此, 在熏蒸产品的顶部, 只测量没有2 。没有2具有21° c 的高沸点, 并且从产品中慢慢消散, 因此可能在熏蒸后一段时间内仍保持在熏蒸产品上。
对于绿叶蔬菜, 如果没有熏蒸没有冲洗与 N2在年底, 没有将与 O2作出反应, 以产生没有2 , 并可能导致持续不2一段时间, 因为新鲜产品通常是在低温下储存。因此, 从缩短熏蒸后的重新时间的角度, 在熏蒸结束时, 也不应用 N2冲洗熏蒸。因此, 监视 no2版本是重要的, 以确定在熏蒸后的产品上没有2将保留多长时间和多少。在熏蒸产品上, 没有2级别可能会影响熏蒸产品的处理或存储方式。
硝酸盐在土壤和植物中自然存在, 包括水果和蔬菜。 一些根蔬菜可以收集高浓度的硝酸盐。蔬菜是硝酸盐的最大食物来源。例如, 新鲜生菜和菠菜的平均硝酸盐水平为 786-1080 和 1420-3400 毫克/千克。欧盟委员会的规章规定生菜和菠菜的硝酸盐含量最高为 2500-4500 和 2000-3000 毫克/千克13。硝酸盐和亚硝酸盐也经常被加入到加工过的肉类中, 如培根、火腿、香肠和热狗, 并且在这些肉类产品中用作防腐剂。硝酸盐和亚硝酸盐作为不熏蒸残留物的测量目的是提供信息, 说明没有熏蒸可以改变熏蒸产品的水平, 而且可能与食品安全没有任何关系。因此, 将硝酸盐和亚硝酸盐作为残留物的测量应视为是可选的, 除非管理机构要求将其作为熏蒸或其他管制程序登记。硝酸盐和亚硝酸盐测量的详细程序也可用21。
在6、7、9之前, 一氧化氮熏蒸对昆虫和螨的所有生命阶段都有很高的功效, 而且与大多数其他熏蒸相比, 没有任何有害残留。鉴于甲基溴熏蒸对采后害虫的控制缺乏有效的替代品, 大多数替代熏蒸在熏蒸产品中留下有毒残留物, 因此不熏蒸可大大扩大研究、开发和注册努力将这一安全有效的采后害虫防治解决方案投放市场。然而, 由于对熏蒸程序的 ULO 条件的复杂性和严格的要求, 许多研究人员可能需要进行培训, 不进行熏蒸研究。我们的目的是提供信息和易于遵循的程序, 实验室没有熏蒸处理对新鲜和储存的农产品的虫害控制。该程序的原则可用于开发大规模无蒸的协议, 用于实际应用。

一氧化氮是一种无处不在的细胞信使分子在所有生物系统2。它被大量释放, 作为火力发电厂和机动车化石燃料燃烧的一种常见污染物, 并大量作为肥料生产中的中间产品生产。在过去的20年中, 对 NO 的深入研究已经产生了大量的知识, 关于它在调节各种生物系统的生物化学和生理过程中的重要性、作用和机制。这一知识已导致各种医疗应用 NO 治疗呼吸和心脏疾病14,15,16。在农业方面, 100 年前没有使用过的加工肉制品为红色颜料保存3。NO 还延长了货架寿命, 提高了各种新鲜产品的采后质量11,12,17,18,19,20。最近, 没有发现是一个有效的熏蒸采后害虫控制6。
没有被证实对测试过的昆虫的所有生命阶段有效 (图 1)。试验结果表明, 害虫种类繁多, 生命阶段不同, 对不同害虫种类的控制具有很大的潜力。NO 熏蒸对害虫的杀灭效果与甲基溴熏蒸的药效相近。但是, 在冷藏温度下不能进行熏蒸。溴甲烷熏蒸需要冷藏产品的升温, 因此可能影响产品质量。例如, 西花蓟马,西马, 和莴苣蚜虫, Nasonovia ribisnigri, 可以控制在2和 3 h 与2.0% 和1.0% 没有熏蒸, 分别在2° c6。NO 熏蒸也比磷化氢熏蒸的速度快得多, 这是主要的甲基溴替代疗法, 可以用超过十天的时间来控制一些害虫4,6,9,10。
一氧化氮熏蒸对外部和内部饲养昆虫都有效。斑点翅果蝇,果蝇 suzukii, 幼虫在被感染的樱桃被控制在 8 h 与2.5% 没有熏蒸的9。苹果蛾的幼虫, Cydia 苹果, 在受感染的苹果完全控制在 24 h 熏蒸与5% 没有在2° c9,10。不熏蒸的功效随着浓度、处理时间和温度的增加而增加6。这些因素可用于对不同种类的昆虫品种进行无熏蒸处理的优化。
但是, 没有与 O2自发地产生任何21的反应。这不仅消耗没有, 但也会造成损害的新鲜产品, 如莴苣 (图 2)。因此, 不得在超低氧 (ULO) 条件下进行熏蒸, 以保持 no。对于新鲜的产品, 没有蒸也需要终止的冲洗与 N2 , 以稀释 no 之前暴露熏蒸产品的环境空气, 以减少其暴露于没有2。这些严格的要求增加了不熏蒸的复杂性和成本。但是, 在技术上不需要熏蒸, 而且成本效益7。所有的大规模不熏蒸的部件都是商用的, 或者可以商业化生产, 包括氮气发电设备, 没有供应, 监测设备 (O2分析仪, 没有米), 和密闭熏蒸室。在低 O2大气层下的控制大气 (CA) 储存和运输已在商业上使用。为不进行熏蒸而生成 N2的能源成本也很适中, 并将因位置7而异。
一氧化氮熏蒸也是安全的新鲜水果和蔬菜, 当终止正确的冲洗与 N2 , 以稀释 NO 第一次之前, 暴露的产品环境空气的8。迄今为止, 对所有的新鲜水果和蔬菜, 如生菜、花椰菜、黄瓜、辣椒、西红柿、草莓、苹果、梨、橙子和柠檬的测试都没有被证明是安全的,8。4 h 熏蒸与1% 不在2° c 为控制西部花蓟马也提高草莓质量。熏蒸后一周, 经过处理的草莓更结实, 色泽更鲜艳, 因此, 与对照8相比, 具有更好的采后品质。
一氧化氮熏蒸也不留下有害残留物熏蒸的新鲜产品。由于没有与 O2产生任何2的反应, 因此, 由于21° c 沸点为 no2, 在产品上不进行熏蒸可能导致没有2的沉积。在水的存在下, 没有2水解形成硝酸 (硝酸3)。因此, 没有熏蒸可能导致硝酸盐 (没有3-) 和亚硝酸盐 (没有2-) 作为待处理商品的残留物。当熏蒸以 N2冲洗终止时, 在新鲜商品的熏蒸后 24 h 的残留物中, 没有熏蒸或极少的硝酸盐或亚硝酸盐的增加, 如9,21。
无反应性质的 o2还需要严格的程序, 以防止 o2在进行不熏蒸处理的过程中。复杂性和严格的程序是最直观的图解, 应该遵循和掌握。在本视频杂志的演示中, 没有对新鲜产品的熏蒸进行解释、说明和演示, 以允许其他研究人员不进行熏蒸研究, 也没有对采后害虫控制进行熏蒸处理。这些努力将有助于加速商业使用 NO 熏蒸控制新鲜和储存产品的采后害虫。

<table><tbody><tr><td>Nitric oxide gas</td><td>Praxair</td><td>UN1660</td><td>99.5% purity</td></tr><tr><td>Nitrogen gas</td><td>Praxair</td><td>UN1066</td><td>Industry grade</td></tr><tr><td>Fumigation chamber</td><td>(custom made)</td><td></td><td>Size: 30&quot;x30&quot;x30&quot;; made of stainless steel with rubber gaskit along the rim.&amp;nbsp; The chamber is sealed by clampdown its lid to the vaseline greased gaskit. The chamber has multiple ports for flushing the chamber and for taking air samples.</td></tr><tr><td>Nitric Oxide Analyzer</td><td>GE Scientific</td><td>NOA 280i analyzer</td><td>Measure NO plus NO2, Nitrate and nitrite</td></tr><tr><td>Model 405nm NO2/NO/Nox monitor</td><td>2B Technologies Inc</td><td></td><td>Ranges: NO (0-2ppm), NO2+NO (0-10ppm)</td></tr><tr><td>Kane 900+ gas monitor</td><td>Kane International</td><td></td><td>With NO, NO2, CO, O2 sensors</td></tr><tr><td>Flowmeter and controllers</td><td>Omega Engineering</td><td></td><td>Flow ranges: 0-1, 0-5, 0-20 LPM</td></tr><tr><td>Tubing, connectors, stopcocks</td><td>Cole-Parmer</td><td></td><td>Tubing: nylon and teflon, sizes: 1/8&quot; and 5/32&quot; (4mm); They fit to connectors and stockcocks&amp;nbsp;</td></tr><tr><td>Oxygen analyzer</td><td>Illinois Instruments</td><td>Model 810</td><td>Ziconia sensor, sensitivity: 0.1ppm, range: 0-100%</td></tr><tr><td>NO2 personal alarm</td><td>SENSIT Technologies</td><td>Sensit P100</td><td>Should be used in conducting large scale NO fumigations outside a fume hood</td></tr><tr><td>Flowmeter and controllers</td><td>Omega Engineering</td><td></td><td>Flow ranges: 0-1, 0-5, 0-20 LPM</td></tr><tr><td>Gastight syringes</td><td>SGE Analytical Science</td><td></td><td>10 ml, 100 ml</td></tr><tr><td>Gastight syringes</td><td>Hamilton Company</td><td></td><td>10uL</td></tr><tr><td>Tubing, connectors, stopcocks</td><td>Cole-Parmer</td><td></td><td>Tubing: nylon and teflon, sizes: 1/8&quot; and 5/32&quot; (4mm); They fit to connectors and stockcocks&amp;nbsp;</td></tr><tr><td>Sodium Iodide</td><td>Fisher Chemical</td><td>S324-100</td><td></td></tr><tr><td>Acetic acid, Glacial</td><td>Fisher Chemical</td><td>UN2789</td><td>&amp;ge;99.7% purity</td></tr><tr><td>Hydrochloric acid</td><td>Cole-Parmer</td><td>SA48-500</td><td>1.0 Normal</td></tr><tr><td>Vanadium(III) Chloride</td><td>Acros Organics</td><td>197000250</td><td>97% purity</td></tr><tr><td>Sodium Hydroxide</td><td>Fisher Chemical</td><td>BPSS266-1</td><td>1 M</td></tr><tr><td>SAHARA S3 Stainless-steel heated bath circulator</td><td>ThermoFisher Scientific</td><td></td><td></td></tr><tr><td>SC 100 Digiital Imersion Circulator</td><td>ThermoFisher Scientific</td><td></td><td></td></tr><tr><td>Oxygen</td><td>Praxair</td><td>*001043</td><td>99.5-100% purity</td></tr><tr><td>Hot Jaw</td><td>Sorbent Systems</td><td></td><td>Mylar bag heat sealer</td></tr><tr><td>Mylar bags</td><td>Sorbent Systems</td><td></td><td></td></tr><tr><td>Flipmate filtration assemblies</td><td>Cole-Parmer</td><td>EW-35202-29</td><td></td></tr><tr><td>15 ml polypropylane tube</td><td>Falcon</td><td></td><td></td></tr><tr><td>Filter Paper P5</td><td>Fisher Scientific</td><td></td><td></td></tr><tr><td>Blender</td><td>Waring</td><td>Blender 7010G</td><td>Model WF2211212</td></tr><tr><td>Dilution device</td><td>Made in our lab</td><td></td><td>Combine the ends of four equal length Teflon microtubing into one connector and have a connector for each end of the four microtubing.</td></tr></tbody></table>

procedures of laboratory fumigation for pest control with nitric oxide gas

一氧化氮 (no) 是一种新发现的熏蒸采后害虫防治方法。本文提供了对新鲜产品进行无熏蒸处理的详细规程, 以及残留分析和产品质量评价的程序。含有新鲜水果和蔬菜的密闭熏蒸室首先用氮气 (N2) 冲洗, 以建立超低氧 (ULO) 环境, 然后注射 NO。熏蒸室被保存在 2-5 ° c 的低温下, 在一定的时间内杀死目标害虫以完成熏蒸处理。在熏蒸处理结束时, 熏蒸室用 N2冲洗, 以使 no 在打开会议厅到环境空气之前稀释 no, 以防止 no 和 O2之间的反应, 因为它不会产生2 , 并可能损坏精致的新鲜产品。在不熏蒸后的不同时间, 无2的顶空、硝酸盐和亚硝酸盐在液体样品中被测定为残留物。经过2周的冷藏后, 对产品质量进行了评估, 以确定不熏蒸对产品质量的影响。保持 O2与 no 的反应是不熏蒸的关键, 也是协议的重要组成部分。测量 NO 水平是有挑战性的, 并提供了一个切实可行的解决方案。此外, 还建议对熏蒸室的 NO 含量以及残留量进行可能的协议修改。无熏蒸有可能成为一种切实可行的替代品, 用于对新鲜和储藏的产品进行采后害虫控制的甲基溴熏蒸。本刊物旨在协助其他研究人员对采后害虫的防治进行无熏蒸研究, 并加速无熏蒸的发展, 以实际应用。

一氧化氮熏蒸的新鲜产品需要终止与 N2冲洗, 以稀释 NO 之前, 打开熏蒸室暴露产品的环境空气。当熏蒸处理通过直接打开会议厅到环境空气中而没有 N2冲洗时终止, 则 no 和 O2之间的反应将导致没有2生产和暴露新鲜产品到没有2经常导致伤害包括褐色污渍, 变色, 和死亡的组织斑点8。微妙的蔬菜和水果, 如生菜, 西葫芦和梨, 容易受到伤害, 没有2。当不使用 N2冲洗正确终止熏蒸时, 熏蒸处理已被证明是安全的, 不会对产品质量造成任何伤害 (图 6和图 7)。事实上, 与草莓上的 unfumigated 对照相比, 没有发现对害虫进行熏蒸处理以提高新鲜产品的采后质量。与对照8相比, 在熏蒸后的一周内, 没有用于控制西方花蓟马的草莓保持了更明亮、更丰富的颜色, 也不那么柔软。用塑料袖子包裹的生菜头可能会在包装通风孔的下方直接造成表面叶子的伤害, 因为如果没有正确终止熏蒸, 则不与 O2产生任何2 。
使用 N2在不熏蒸的结尾处冲洗, 不会影响到熏蒸产品的2版本。当不以 N2冲洗终止熏蒸时, 在处理和控制之间没有2释放率的显著差异。在熏蒸结束时, 没有用空气冲洗过的熏蒸处理, 但是, 与控件相比, 没有更高的2释放率, 并且没有2的释放随时间推移而下降。
对于大多数新鲜的产品, 包括生菜, 花椰菜, 草莓, 苹果, 橙,等,没有任何3-或2级别之间没有明显的区别, 这是以 N2终止的处理冲洗和控制。只有当没有经过正常空气冲洗而终止熏蒸处理时, 所有熏蒸产品中的任何3-和2浓度都比控制和 N2冲洗过的烟熏更高。产品.在熏蒸和控制产品 (表 1和表 2) 中, 没有任何2-浓度通常是不可检测的。因此, 熏蒸后24小时内没有任何熏蒸过的新鲜产品的残留量, 并在氮气冲洗后适当终止。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56309/56309fig1.jpg"> 图 1: 不熏蒸对昆虫和螨的影响.<a href="//cloudflare.jove.com/files/ftp_upload/56309/56309fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56309/56309fig2.jpg"> 图 2:对生菜的伤害的演示不2从 no 和 O 之间的反应2 <a href="//cloudflare.jove.com/files/ftp_upload/56309/56309fig2large.jpg" target="_blank">.请单击此处查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56309/56309fig3.jpg"> 图 3:无熏蒸程序的流程图.<a href="//cloudflare.jove.com/files/ftp_upload/56309/56309fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56309/56309fig4.jpg"> 图 4:使用稀释装置的方法和无传感器的流感气体监测器在 large-scale 无熏蒸测试中测量 no 水平.<a href="//cloudflare.jove.com/files/ftp_upload/56309/56309fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56309/56309fig5.jpg"> 图 5:比较熏蒸处理终止于 N2冲洗和空气冲洗对新鲜水果和蔬菜采后质量的影响.<a href="//cloudflare.jove.com/files/ftp_upload/56309/56309fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/56309/56309fig6.jpg"> 图 6:三种处理方法 (c、T1、T2) 14 天后的生菜、花椰菜和苹果的后处理质量, 以 c、T1 和 T2 代表控制, 熏蒸终止, N2冲洗, 并分别以空气冲洗结束熏蒸.<a href="//cloudflare.jove.com/files/ftp_upload/56309/56309fig6large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>

<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/56309/56309fig7.jpg"> 图 7:三种处理方法 (c、T1、T2) 14 天后的柑桔、梨和桃子的品质, 以 c、T1 和 T2 为对照, 熏蒸终止, N2冲洗, 并分别以空气冲洗结束熏蒸.<a href="//cloudflare.jove.com/files/ftp_upload/56309/56309fig7large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>


<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td>产品</td>
			<td>NO (%)</td>
			<td>治疗</td>
			<td>没有3- (mg/100 g)</td>
			<td>没有2- (mg/100 g)</td>
		</tr>
<tr>
<td rowspan="3">苹果</td>
			<td>5。0</td>
			<td>无空气</td>
			<td>1.60±0.12</td>
			<td>0.50±0.16</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>1.36±0.13 ab</td>
			<td>0.03±0.01 湾</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>0.76±0.28 湾</td>
			<td>0 b</td>
		</tr>
<tr>
<td rowspan="3">杏</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>1.84±0.14</td>
			<td>0.21±0.02</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>0.92±0.17 湾</td>
			<td>0 b</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>0.54±0.01 湾</td>
			<td>0 b</td>
		</tr>
<tr>
<td rowspan="3">芦笋</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>2.19±0.13</td>
			<td>0.08±0.04</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>0.70±0.03 湾</td>
			<td>0 a</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>0.84±0.07 湾</td>
			<td>0 a</td>
		</tr>
<tr>
<td rowspan="3">莓</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>2.74±0.46</td>
			<td>0.14±0.02</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>1.24±0.19 湾</td>
			<td>0 b</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>1.22±0.15 湾</td>
			<td>0 b</td>
		</tr>
<tr>
<td rowspan="3">兰花</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>18.69±3.75</td>
			<td>0.17±0.06</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>18.51±3.42</td>
			<td>0 b</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>12.26±2.31</td>
			<td>0 b</td>
		</tr>
<tr>
<td rowspan="3">樱桃</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>1.75±0.11</td>
			<td>0</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>0.56±0.09 湾</td>
			<td>0</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>0.65±0.08 湾</td>
			<td>0</td>
		</tr>
<tr>
<td rowspan="3">大蒜</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>5.05±0.45</td>
			<td>0.14±0.02</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>4.45±0.79</td>
			<td>0 b</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>5.01±0.69</td>
			<td>0 b</td>
		</tr>
<tr>
<td rowspan="3">葡萄</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>6.32±0.68</td>
			<td>0</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>2.38±0.43 湾</td>
			<td>0</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>2.74±0.25 湾</td>
			<td>0</td>
		</tr>
<tr>
<td rowspan="3">胡椒</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>9.26±0.35</td>
			<td>0.71±0.12</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>6.75±0.68 湾</td>
			<td>0.02±0.01 湾</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>6.23±0.72 湾</td>
			<td>0 b</td>
		</tr>
<tr>
<td rowspan="3">猕猴桃</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>1.66±0.55</td>
			<td>0</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>1.25±0.09</td>
			<td>0</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>1.41±0.31</td>
			<td>0</td>
		</tr>
<tr>
<td rowspan="3">生菜</td>
			<td>2。0</td>
			<td>无空气</td>
			<td>112.85±20.17a</td>
			<td>7.99±2.02</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>38.97±5.87 湾</td>
			<td>0.1±0.1 湾</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>40.64±10.81b</td>
			<td>0 b</td>
		</tr>
<tr>
<td rowspan="3">橙</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>1.22±0.13</td>
			<td>0.27±0.05</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>1.05±0.05</td>
			<td>0.02±0.01 湾</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>1.24±0.22</td>
			<td>0 b</td>
		</tr>
<tr>
<td rowspan="3">梅花</td>
			<td>3。0</td>
			<td>无空气</td>
			<td>1.04±0.08</td>
			<td>0</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>0.63±0.04 湾</td>
			<td>0</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>0.84±0.11 ab</td>
			<td>0</td>
		</tr>
<tr>
<td rowspan="3">草莓</td>
			<td>2。5</td>
			<td>无空气</td>
			<td>6.01±0.62</td>
			<td>0</td>
		</tr>
<tr>
<td></td>
			<td>NO-N2
</td>
			<td>5.30±0.77</td>
			<td>0</td>
		</tr>
<tr>
<td></td>
			<td>控制</td>
			<td>6.16±1.06</td>
			<td>0</td>
		</tr>
</tbody></table>表 1: 硝酸盐和亚硝酸盐含量为24小时后的残留物, 16 h 一氧化氮对新鲜水果和蔬菜进行熏蒸.对于每种产品, 根据 Tukey HSD 多范围测试 (P ≤0.05), 后跟不同字母的值会有显著差异。转载自杨和刘 (2017)。

Watch this Scientific Journal Video about Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas at JoVE.com

Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas

本文介绍了一氧化氮 (no) 熏蒸后的害虫防治方案。熏蒸室用氮气 (N2) 冲洗, 以建立超低氧条件, 然后再注入 NO。最后, 在将产品暴露于环境空气以防止暴露于无2之前, 商会用 N2冲洗, 以稀释 no。

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 ...

procedures-laboratory-fumigation-for-pest-control-with-nitric-oxide

Research

JoVE Journal

Environment

17.1K 次观看.  USDA-ARS. 本文介绍了一氧化氮 (no) 熏蒸后的害虫防治方案。熏蒸室用氮气 (N2) 冲洗, 以建立超低氧条件, 然后再注入 NO。最后, 在将产品暴露于环境空气以防止暴露于无2之前, 商会用 N2冲洗, 以稀释 no。

视频: Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. Herein, nitrogen is presented as a novel supercritical drying fluid for specialized applications such as in the processing of reactive porous materials, where carbon dioxide and other fluids are not appropriate due to their higher chemical reactivity. Nitrogen exhibits similar physical properties in the near-critical region of its phase diagram as compared to carbon dioxide: a widely tunable density up to ~1 g ml-1, modest critical pressure (3.4 MPa), and small molecular diameter of ~3.6 &#197;. The key to achieving a high solvation power of nitrogen is to apply a processing temperature in the range of 80-150 K, where the density of nitrogen is an order of magnitude higher than at similar pressures near ambient temperature. The detailed solvation properties of nitrogen, and especially its selectivity, across a wide range of common target species of extraction still require further investigation. Herein we describe a protocol for the supercritical nitrogen processing of porous magnesium borohydride.

Nitrogen is an effective supercritical fluid for extraction or drying processes due to its small molecular size, high density in the near-liquid supercritical regime, and chemical inertness. We present a supercritical nitrogen drying protocol for the purification treatment of reactive, porous materials.

超临界氮处理的活性多孔材料的净化

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. ...

科研

化学

Assessment of Labile Organic Carbon in Soil Using Sequential Fumigation Incubation Procedures

Management practices and environmental changes can alter soil nutrient and carbon cycling. Soil labile organic carbon, a readily decomposable C pool, is highly sensitive to disturbance. It is also the primary substrate for soil microorganisms, which is fundamental to nutrient cycling. Due to these attributes, labile organic carbon (LOC) has been identified as an indicator parameter for soil health. Quantifying the turnover rate of LOC also aids in understanding changes in soil nutrient cycling processes. A sequential fumigation incubation method has been developed to estimate soil LOC and potential C turnover rate. The method requires fumigating soil samples and quantifying CO2-C respired during a 10 day incubation period over a series of fumigation-incubation cycles. Labile organic C and potential C turnover rate are then extrapolated from accumulated CO2 with a negative exponential model. Procedures for conducting this method are described.

Labile organic carbon (LOC) and the potential carbon turnover rate are sensitive indicators of changes in soil nutrient cycling processes. Details are provided for a method based on fumigating and incubating soil in a series of cycles and using the CO2 accumulated during the incubation periods to estimate these parameters.

活性有机碳评估土壤中连续熏蒸孵化程序

Management practices and environmental changes can alter soil nutrient and carbon cycling. Soil labile organic carbon, a readily decomposable C pool, is ...

环境科学

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence the oxidizing capacity of the atmosphere through interactions with ozone and hydroxyl radicals. The main sink of NOx is the formation and deposition of nitric acid, a component of acid rain and a bioavailable nutrient. NOx is emitted from a mixture of natural and anthropogenic sources, which vary in space and time. The collocation of multiple sources and the short lifetime of NOx make it challenging to quantitatively constrain the influence of different emission sources and their impacts on the environment. Nitrogen isotopes of NOx have been suggested to vary amongst different sources, representing a potentially powerful tool to understand the sources and transport of NOx. However, previous methods of collecting atmospheric NOx integrate over long (week to month) time spans and are not validated for the efficient collection of NOx in relevant, diverse field conditions. We report on a new, highly efficient field-based system that collects atmospheric NOx for isotope analysis at a time resolution between 30 min and 2 hr. This method collects gaseous NOx in solution as nitrate with 100% efficiency under a variety of conditions. Protocols are presented for collecting air in urban settings under both stationary and mobile conditions. We detail the advantages and limitations of the method and demonstrate its application in the field. Data from several deployments are shown to 1) evaluate field-based collection efficiency by comparisons with in situ NOx concentration measurements, 2) test the stability of stored solutions before processing, 3) quantify in situ reproducibility in a variety of urban settings, and 4) demonstrate the range of N isotopes of NOx detected in ambient urban air and on heavily traveled roadways.

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Previous work suggests that the nitrogen isotopic composition of atmospheric nitrogen oxides might distinguish the influence of different sources in the environment. We report on an automated, mobile, field-based method for the high collection efficiency of atmospheric NOx for N isotopic analysis at an hourly time resolution.

自动化，高清晰度移动采集系统对NO的氮同位素分析<sub系列&gt; X</sub

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence ...

Analytical Techniques for Assaying Nitric Oxide Bioactivity

Nitric oxide (NO) is a diatomic free radical that is extremely short lived in biological systems (less than 1 second in circulating blood)1. NO may be considered one of the most important signaling molecules produced in our body, regulating essential functions including but not limited to regulation of blood pressure, immune response and neural communication. Therefore its accurate detection and quantification in biological matrices is critical to understanding the role of NO in health and disease. With such a short physiological half life of NO, alternative strategies for the detection of reaction products of NO biochemistry have been developed. The quantification of relevant NO metabolites in multiple biological compartments provides valuable information with regards to in vivo NO production, bioavailability and metabolism. Simply sampling a single compartment such as blood or plasma may not always provide an accurate assessment of whole body NO status, particularly in tissues. The ability to compare blood with select tissues in experimental animals will help bridge the gap between basic science and clinical medicine as far as diagnostic and prognostic utility of NO biomarkers in health and disease. Therefore, extrapolation of plasma or blood NO status to specific tissues of interest is no longer a valid approach. As a result, methods continue to be developed and validated which allow the detection and quantification of NO and NO-related products/metabolites in multiple compartments of experimental animals in vivo. The established paradigm of NO biochemistry from production by NO synthases to activation of soluble guanylyl cyclase (sGC) to eventual oxidation to nitrite (NO2-) and nitrate (NO3-) may only represent part of NO's effects in vivo. The interaction of NO and NO-derived metabolites with protein thiols, secondary amines, and metals to form S-nitrosothiols (RSNOs), N-nitrosamines (RNNOs), and nitrosyl-heme respectively represent cGMP-independent effects of NO and are likely just as important physiologically as activation of sGC by NO. A true understanding of NO in physiology is derived from in vivo experiments sampling multiple compartments simultaneously. Nitric oxide (NO) methodology is a complex and often confusing science and the focus of many debates and discussion concerning NO biochemistry. The elucidation of new mechanisms and signaling pathways involving NO hinges on our ability to specifically, selectively and sensitively detect and quantify NO and all relevant NO products and metabolites in complex biological matrices. Here, we present a method for the rapid and sensitive analysis of nitrite and nitrate by HPLC as well as detection of free NO in biological samples using in vitro ozone based chemiluminescence with chemical derivitazation to determine molecular source of NO as well as ex vivo with organ bath myography.

The endogenous production of nitric oxide (NO) regulates a wide variety of biological functions. It is becoming increasingly clear that disruption or dysregulation of NO based signaling is involved in many human diseases. Methods to quantify relevant NO metabolites may provide novel diagnostic or prognostic biomarkers for human disease.

为含量测定一氧化氮生物活性分析技术

Nitric oxide (NO) is a diatomic free radical that is extremely short lived in biological systems (less than 1 second in circulating blood)1. NO may be ...

医学

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

The importance of understanding the fate of nitrate (NO3&#8722;), which is the dominant N species transferred from terrestrial to aquatic ecosystems, has been increasing because global nitrogen loads have dramatically increased following industrialization. Dissimilatory nitrate reduction to ammonium (DNRA) and denitrification are both microbial processes that use NO3&#8722; for respiration. Compared to denitrification, quantitative determinations of the DNRA activity have been carried out only to a limited extent. This has led to an insufficient understanding of the importance of DNRA in NO3&#8722; transformations and the regulating factors of this process. The objective of this paper is to provide a detailed procedure for the measurement of the potential DNRA rate in environmental samples. In brief, the potential DNRA rate can be calculated from the 15N-labeled ammonium (15NH4+) accumulation rate in 15NO3&#8722; added incubation. The determination of the 14NH4+ and 15NH4+ concentrations described in this paper is comprised of the following steps. First, the NH4+ in the sample is extracted and trapped on an acidified glass filter as ammonium salt. Second, the trapped ammonium is eluted and oxidized to NO3&#8722; via persulfate oxidation. Third, the NO3&#8722; is converted to N2O via an N2O reductase deficient denitrifier. Finally, the converted N2O is analyzed using a previously developed quadrupole gas chromatography&#8211;mass spectrometry system. We applied this method to salt marsh sediments and calculated their potential DNRA rates, demonstrating that the proposed procedures allow a simple and more rapid determination compared to previously described methods.

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

A series of methods to determine the potential DNRA rate based on 14NH4+/15NH4+ analyses is provided in detail. NH4+ is converted into N2O via several steps and analyzed using quadrupole gas chromatography&#8211;mass spectrometry.

基于14NH 4 + /4+ 15NH 4= 通过顺序转换为 N2O 的分析，测量异化硝酸盐降低至铵的潜在率

The importance of understanding the fate of nitrate (NO3&#8722;), which is the dominant N species transferred from terrestrial to aquatic ecosystems, has ...

Novel Whole-tissue Quantitative Assay of Nitric Oxide Levels in Drosophila Neuroinflammatory Response

Neuroinflammation is a complex innate immune response vital to the healthy function of the central nervous system (CNS). Under normal conditions, an intricate network of inducers, detectors, and activators rapidly responds to neuron damage, infection or other immune infractions. This inflammation of immune cells is intimately associated with the pathology of neurodegenerative disorders, such as Parkinson&#39;s disease (PD), Alzheimer&#39;s disease and ALS. Under compromised disease states, chronic inflammation, intended to minimize neuron damage, may lead to an over-excitation of the immune cells, ultimately resulting in the exacerbation of disease progression. For example, loss of dopaminergic neurons in the midbrain, a hallmark of PD, is accelerated by the excessive activation of the inflammatory response. Though the cause of PD is largely unknown, exposure to environmental toxins has been implicated in the onset of sporadic cases. The herbicide paraquat, for example, has been shown to induce Parkinsonian-like pathology in several animal models, including Drosophila melanogaster. Here, we have used the conserved innate immune response in Drosophila to develop an assay capable of detecting varying levels of nitric oxide, a cell-signaling molecule critical to the activation of the inflammatory response cascade and targeted neuron death. Using paraquat-induced neuronal damage, we assess the impact of these immune insults on neuroinflammatory stimulation through the use of a novel, quantitative assay. Whole brains are fully extracted from flies either exposed to neurotoxins or of genotypes that elevate susceptibility to neurodegeneration then incubated in cell-culture media. Then, using the principles of the Griess reagent reaction, we are able to detect minor changes in the secretion of nitric oxide into cell-culture media, essentially creating a primary live-tissue model in a simple procedure. The utility of this model is amplified by the robust genetic and molecular complexity of Drosophila melanogaster, and this assay can be modified to be applicable to other Drosophila tissues or even other small, whole-organism inflammation models.

Novel Whole-tissue Quantitative Assay of Nitric Oxide Levels in Drosophila Neuroinflammatory Response

Levels of the inflammatory cell-signaling molecule nitric oxide (NO) are commonly assayed using Griess reagent. In this protocol, we have created a modified Griess assay utilizing live Drosophila brain tissue in order to detect the secretion of NO in a simple, quantifiable and highly repeatable method.

Neuroinflammation is a complex innate immune response vital to the healthy function of the central nervous system (CNS). Under normal conditions, an ...

免疫与感染

Encapsulating Cytochrome c in Silica Aerogel Nanoarchitectures without Metal Nanoparticles while Retaining Gas-phase Bioactivity

Applications such as sensors, batteries, and fuel cells have been improved through the use of highly porous aerogels when functional compounds are encapsulated within the aerogels. However, few reports on encapsulating proteins within sol&#8211;gels that are processed to form aerogels exist. A procedure for encapsulating cytochrome c (cyt. c) in silica (SiO2) sol-gels that are supercritically processed to form bioaerogels with gas-phase activity for nitric oxide (NO) is presented. Cyt. c is added to a mixed silica sol under controlled protein concentration and buffer strength conditions. The sol mixture is then gelled and the liquid filling the gel pores is replaced through a series of solvent exchanges with liquid carbon dioxide. The carbon dioxide is brought to its critical point and vented off to form dry aerogels with cyt. c encapsulated inside. These bioaerogels are characterized with UV-visible spectroscopy and circular dichroism spectroscopy and can be used to detect the presence of gas-phase nitric oxide. The success of this procedure depends on regulating the cyt. c concentration and the buffer concentration and does not require other components such as metal nanoparticles. It may be possible to encapsulate other proteins using a similar approach making this procedure important for potential future bioanalytical device development.

Encapsulating Cytochrome c in Silica Aerogel Nanoarchitectures without Metal Nanoparticles while Retaining Gas-phase Bioactivity

This procedure describes how to encapsulate cytochrome c (cyt. c) in silica (SiO2) sol-gels, process these gels to form bioaerogels, and use these bioaerogels to rapidly recognize nitric oxide (NO) through a gas-phase reaction. This type of protocol may aid in the future development of biosensors or other bioanalytical devices.

细胞色素封装<em&gt;ç</em&gt;在二氧化硅气凝胶Nanoarchitectures没有金属纳米粒子，同时保持气相生物活性

Applications such as sensors, batteries, and fuel cells have been improved through the use of highly porous aerogels when functional compounds are ...

生物工程

A Novel Inhalation Mask System to Deliver High Concentrations of Nitric Oxide Gas in Spontaneously Breathing Subjects

Nitric Oxide (NO) is administered as gas for inhalation to induce selective pulmonary vasodilation. It is a safe therapy, with few potential risks even if administered at high concentration. Inhaled NO gas is routinely used to increase systemic oxygenation in different disease conditions. The administration of high concentrations of NO also exerts a virucidal effect in vitro. Owing to its favorable pharmacodynamic and safety profiles, the familiarity in its use by critical care providers, and the potential for a direct virucidal effect, NO is clinically used in patients with coronavirus disease-2019 (COVID-19). Nevertheless, no device is currently available to easily administer inhaled NO at concentrations higher than 80 parts per million (ppm) at various inspired oxygen fractions, without the need for dedicated, heavy, and costly equipment. The development of a reliable, safe, inexpensive, lightweight, and ventilator-free solution is crucial, particularly for the early treatment of non-intubated patients outside of the intensive care unit (ICU) and in a limited-resource scenario. To overcome such a barrier, a simple system for the non-invasive NO gas administration up to 250 ppm was developed using standard consumables and a scavenging chamber. The method has been proven safe and reliable in delivering a specified NO concentration while limiting nitrogen dioxide levels. This paper aims to provide clinicians and researchers with the necessary information on how to assemble or adapt such a system for research purposes or clinical use in COVID-19 or other diseases in which NO administration might be beneficial.

This simple and highly adaptable system device for the inhalation of high-concentration nitric oxide (NO) gas does not require mechanical ventilators, positive pressure, or high gas flows. Standard medical consumables and a snug-fitting mask are used to safely deliver NO gas to spontaneously breathing subjects.

一种新型吸入面膜系统，可在自发呼吸受试者中提供高浓度的一氧化氮气体

Nitric Oxide (NO) is administered as gas for inhalation to induce selective pulmonary vasodilation. It is a safe therapy, with few potential risks even if ...

Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds

Nitric oxide (NO) activity in vivo is the combined results of its direct effects, the action of its derivatives generated from NO autoxidation, and the effects of nitrosated compounds. Measuring NO metabolites is essential to studying NO activity both at vascular levels and in other tissues, especially in the experimental settings where exogenous NO is administered. Ozone-based chemiluminescence assays allow precise measurements of NO and NO metabolites in both fluids (including plasma, tissue homogenates, cell cultures) and gas mixtures (e.g., exhaled breath). NO reacts with ozone to generate nitrogen dioxide in an excited state. The consequent light emission allows photodetection and the generation of an electric signal reflecting the NO content of the sample. Aliquots from the same sample can be used to measure specific NO metabolites, such as nitrate, nitrite, S-nitrosothiols, and iron-nitrosyl complexes. In addition, NO consumed by cell-free hemoglobin is also quantified with chemiluminescence analysis. An illustration of all these techniques is provided.

Here, we present protocols for detecting nitric oxide and its biologically relevant derivatives using chemiluminescence-based assays with high sensitivity.

基于化学发光的检测方法，用于检测自氧化和亚硝化化合物中的一氧化氮及其衍生物

Nitric oxide (NO) activity in vivo is the combined results of its direct effects, the action of its derivatives generated from NO autoxidation, and the ...

Measuring Nitrite and Nitrate, Metabolites in the Nitric Oxide Pathway, in Biological Materials using the Chemiluminescence Method

Nitric oxide (NO) is one of the main regulator molecules in vascular homeostasis and also a neurotransmitter. Enzymatically produced NO is oxidized into nitrite and nitrate by interactions with various oxy-heme proteins and other still not well known pathways. The reverse process, reduction of nitrite and nitrate into NO had been discovered in mammals in the last decade and it is gaining attention as one of the possible pathways to either prevent or ease a whole range of cardiovascular, metabolic and muscular disorders that are thought to be associated with decreased levels of NO. It is therefore important to estimate the amount of NO and its metabolites in different body compartments &#8212; blood, body fluids and the various tissues. Blood, due to its easy accessibility, is the preferred compartment used for estimation of NO metabolites. Due to its short lifetime (few milliseconds) and low sub-nanomolar concentration, direct reliable measurements of blood NO in vivo present great technical difficulties. Thus NO availability is usually estimated based on the amount of its oxidation products, nitrite and nitrate. These two metabolites are always measured separately. There are several well established methods to determine their concentrations in biological fluids and tissues. Here we present a protocol for chemiluminescence method (CL), based on spectrophotometrical detection of NO after nitrite or nitrate reduction by tri-iodide or vanadium(III) chloride solutions, respectively. The sensitivity for nitrite and nitrate detection is in low nanomolar range, which sets CL as the most sensitive method currently available to determine changes in NO metabolic pathways. We explain in detail how to prepare samples from biological fluids and tissues in order to preserve original amounts of nitrite and nitrate present at the time of collection and how to determine their respective amounts in samples. Limitations of the CL technique are also explained.

Nitric oxide (NO) is an important signaling molecule in vascular homeostasis. NO production in vivo is too low for direct measurement. Chemiluminescence provides useful insight into NO cycle via measuring its precursors and oxidation products, nitrite and nitrate. Nitrite / nitrate determination in body tissues and fluids is explained.

用化学发光法测定硝酸盐和亚硝酸盐，代谢产物中的一氧化氮途径，在生物材料

Nitric oxide (NO) is one of the main regulator molecules in vascular homeostasis and also a neurotransmitter. Enzymatically produced NO is oxidized into ...

一氧化氮气体防治害虫实验室熏蒸程序

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