An assay for angiotensin-converting enzyme using capillary zone electrophoresis

A sensitive and rapid method was developed for angiotensin-converting enzyme (ACE) activity determination by capillary zone electrophoresis. Hippuryl-l-histidyl-l-leucine, a synthetic tripeptide, was used as the ACE-specific substrate. Capillary zone electrophoresis was employed to separate the products of the enzymatic reaction and the ACE activity was determined by quantification of hippuric acid, a result of the enzymatic reaction on the tripeptide. The capillary electrophoresis was performed in a 27 cm x 75 micrometer i.d. fused-silica capillary using 200 mM boric acid-borate buffer (pH 9.0) as a run buffer with an applied voltage of 8.1 kV at a capillary temperature of 23 degrees C. The electrophoresis was monitored at 228 nm. Each electrophoretic run requires only a nanoliter of the enzymatic reactant solution, at only 6 min, rendering a powerful tool for the ACE assay.     

天然林和人工林外来入侵和本地植物对比研究: 以弄岗国家级自然保护区为例

外来植物的入侵严重威胁了自然保护区的生物多样性。为探讨自然保护区内天然林和人工林林下外来植物入侵状况及其与本地优势植物的种间关系, 本研究以弄岗国家级自然保护区为研究区域, 结合保护区内4种生境72个样方的野外调查数据, 利用生态位宽度、生态位重叠和种间联结指数比较了不同生境中外来入侵草本植物的多样性和生态位宽度以及外来入侵草本植物与本土优势草本植物的生态位重叠和种间联结。结果表明: 弄岗国家级自然保护区4种生境共记录6种外来入侵草本植物, 隶属于3科6属, 其中菊科物种数量最多。外来入侵植物多样性呈现出秋枫(Bischofia javanica)人工林 > 麻竹(Dendrocalamus latiflorus)次生林 > 人面子(Dracontomelon duperreanum)人工林 > 广西澄广花(Orophea polycarpa)次生林的特征。除广西澄广花次生林生境的外来入侵草本植物丰富度与本土草本植物丰富度呈显著正相关外, 其余生境均无显著的相关关系。三叶鬼针草(Bidens pilosa)的生态位宽度最大, 为4种生境均有分布的外来入侵植物。4种生境的外来入侵植物与本土优势植物生态位重叠和种间联结程度均较低, 种间竞争较弱。本研究明确了弄岗国家级自然保护区天然林和人工林中外来入侵草本植物的分布及其与本土草本植物的种间关系。     

储粮环境挥发性化合物与储粮害虫的关系研究进展

每种粮食的储粮环境中都存在有其特征性挥发物,储粮害虫的发生对储粮环境中挥发物具有重要影响。本文简述了顶空式固相微萃取法、浸入式固相微萃取法、电子鼻检测法等储粮挥发物的提取方法及其优缺点,对小麦 Triticum aestivum L.、稻谷 Olyza sativa L.、玉米 Zea mays L.和燕麦 Avena sativa L.等主要储藏粮食种类的挥发性化合物成分、粮食挥发物对昆虫行为反应的影响、主要储粮害虫(赤拟谷盗 Tribolium castaneum、锈赤扁谷盗 Cryptolestes ferrugineus 和象虫 Sitophilus spp.)发生与粮食挥发物的关系等研究进展进行综述,探讨了储粮环境挥发性化合物与储粮害虫关系未来的研究方向,以期对今后储粮害虫生态防治研究与应用提供参考信息。     

Imaging depth variations in hyperspectral imaging: Development of a method to detect tumor up to the required tumor‐free margin width

Hyperspectral imaging is a promising technique for resection margin assessment during cancer surgery. Thereby, only a specific amount of the tissue below the resection surface, the clinically defined margin width, should be assessed. Since the imaging depth of hyperspectral imaging varies with wavelength and tissue composition, this can have consequences for the clinical use of hyperspectral imaging as margin assessment technique. In this study, a method was developed that allows for hyperspectral analysis of resection margins in breast cancer. This method uses the spectral slope of the diffuse reflectance spectrum at wavelength regions where the imaging depth in tumor and healthy tissue is equal. Thereby, tumor can be discriminated from healthy breast tissue while imaging up to a similar depth as the required tumor‐free margin width of 2 mm. Applying this method to hyperspectral images acquired during surgery would allow for robust margin assessment of resected specimens. In this paper, we focused on breast cancer, but the same approach can be applied to develop a method for other types of cancer.     

十溴联苯醚与锌复合污染胁迫下土壤酶和呼吸强度的响应

为了了解多溴联苯醚与重金属复合污染对土壤微生态的影响,采用室内模拟土培方法研究了十溴联苯醚(decabromodiphenyl ether,BDE-209)和锌(Zn SO4·7H2O)单一及复合污染处理对土壤过氧化氢酶和蔗糖酶活性及土壤呼吸强度的影响。结果表明:短期(1~7 d)处理条件下,土壤蔗糖酶和过氧化氢酶对BDE-209和Zn2+单一和复合污染均表现出较高的敏感性,但随着暴露时间的延长,酶活性有逐渐恢复至对照组水平的趋势;最高浓度100 mg·kg-1的BDE-209与最高浓度1000 mg·kg-1的Zn2+复合处理组,蔗糖酶和过氧化氢酶活性则始终处于受抑制状态;BDE-209和Zn2+复合污染处理对土壤过氧化氢酶活性的影响在暴露前期主要为拮抗作用,而后期以协同作用为主,对土壤蔗糖酶的影响在不同时期分别表现出加合作用、拮抗作用和协同作用;BDE-209与Zn2+复合处理对土壤呼吸的影响呈现"促进-抑制-促进-抑制"的规律,但无论是促进作用还是抑制作用,其强度随时间而减弱。     

测墒补灌对小麦旗叶光合特性及酶活性的影响

以‘济麦20’为供试材料,通过田间试验,在拔节期和开花期设置土壤相对含水量为65%(W₆₅)、70%(W₇₀)和75%(W₇₅)的测墒补灌处理,以全生育期不灌溉为对照(CK),研究不同测墒补灌水平对旗叶光合特性及酶活性的影响.结果表明: W₇₀处理小麦旗叶净光合速率、蔗糖含量和磷酸蔗糖合成酶(SPS)活性在花后14～21 d均显著高于其他处理.成熟期W70处理干物质量与W₇₅处理无显著差异,但显著高于W₆₅处理和CK;W₇₀处理单茎质量显著高于其他处理.W₇₀处理超氧化物歧化酶和过氧化氢酶活性及可溶性蛋白含量在花后14～28 d显著高于其他处理,丙二醛含量在花后14～28 d显著低于CK和W₆₅处理,与W₇₅处理无显著差异.2012—2013年和2013—2014年W₇₀处理小麦籽粒产量分别为8941.4和9125.4 kg·hm^-2,与W₇₅处理无显著差异,显著高于W₆₅处理和CK;W₇₀处理水分利用效率显著高于其他处理.在本试验条件下,拔节期和开花期0
～140 cm土层平均土壤相对含水量均以70%为节水高产高效的最佳灌溉处理.     

Acute pancreatic beta cell apoptosis by IL-1β is responsible for postburn hyperglycemia: Evidence from humans and mice

Background

Acute hyperglycemia is regarded as a risk factor for critically ill patients; however, insufficient understanding of its nature and underlying mechanisms hinders widespread adoption of glycemic control in critical care units.