Pitfalls in the sample preparation and analysis of N-acylethanolamines

N-acylethanolamines (NAEs) are a group of lipid mediators synthesized in response to a number of physiological and pathological stimuli. Because of the low tissue concentrations of NAEs, analyses often include liquid extraction followed by solid-phase extraction and subsequent quantitation by LC/MS or GC/MS. Reported levels of NAEs vary considerably, however, and often no explanation is given for these discrepancies. Brought on by difficulties encountered during method development, the effects of using four different brands of silica-containing solid phase extraction (SPE) columns and five different brands of chloroform for sample preparation were investigated. Considerable variation in the retention and recoveries of seven NAEs and 2-arachidonoylglycerol existed between the SPE columns. Furthermore, it was found that some chloroforms contained quantifiable amounts of N-palmitoylethanolamine and N-stearoylethanolamine. Finally, it was found that use of one of the chloroforms resulted in a loss of N-oleoylethanolamine from solution due to addition of chlorine to the ω-9 bond. The identity of this reaction product was confirmed by LC-MS/MS and NMR. It is recommended that these aspects of sample preparation and analysis should be thoroughly validated during method development and the relevant information on specific brands used be reported in future communications in order to better estimate the validity of reported quantitative data.     

CAT & MAUS: A novel system for true dynamic motion measurement of underlying bony structures with compensation for soft tissue movement

Optoelectronic motion capture systems are widely employed to measure the movement of human joints. However, there can be a significant discrepancy between the data obtained by a motion capture system (MCS) and the actual movement of underlying bony structures, which is attributed to soft tissue artefact. In this paper, a computer-aided tracking and motion analysis with ultrasound (CAT & MAUS) system with an augmented globally optimal registration algorithm is presented to dynamically track the underlying bony structure during movement. The augmented registration part of CAT & MAUS was validated with a high system accuracy of 80%. The Euclidean distance between the marker-based bony landmark and the bony landmark tracked by CAT & MAUS was calculated to quantify the measurement error of an MCS caused by soft tissue artefact during movement. The average Euclidean distance between the target bony landmark measured by each of the CAT & MAUS system and the MCS alone varied from 8.32 mm to 16.87 mm in gait. This indicates the discrepancy between the MCS measured bony landmark and the actual underlying bony landmark. Moreover, Procrustes analysis was applied to demonstrate that CAT & MAUS reduces the deformation of the body segment shape modeled by markers during motion. The augmented CAT & MAUS system shows its potential to dynamically detect and locate actual underlying bony landmarks, which reduces the MCS measurement error caused by soft tissue artefact during movement.     

不同生长调节剂及基质对越南粉苞茉莉扦插生根的影响

为探索越南粉苞茉莉(Jasminum dichotomum)扦插生根的影响因素,建立扦插繁育技术体系,以1年生越南粉苞茉莉枝条为插穗,采用L16(44)正交试验,探讨生长调节剂种类及其浓度、处理时间、基质种类对越南粉苞茉莉茎段扦插生根的影响,利用排队评分法和公式评分法对正交试验进行分析。结果表明,A2B3C3D2为试验的最优处理组合,即将插穗在250 mg·L-1 IBA和500 mg·L-1 NAA混合药剂中浸泡20 min后扦插于沙子上。     

14种中国典型极小种群野生植物繁育特性和人工繁殖研究进展

繁殖是植物种群更新与维持的重要环节。包括极小种群野生植物在内的受威胁物种, 其濒危原因是在长期演化过程中自身繁育力的衰退、生活力的下降等内在因素和人类的过度采挖和生境的破坏等外在因素共同作用的结果。对极小种群野生植物进行高效的人工繁殖, 能扩大种群数量并应用于迁地保护、自然回归和满足商品市场的需求, 有利于其种质资源的保护和可持续利用。为了保持物种的遗传多样性, 采用种子繁殖育苗是有效的方法, 扦插、嫁接和组织培养技术等无性繁殖方法则可用于对难以用种子繁殖的种类进行快速繁殖。本文对14种中国典型极小种群野生植物的繁殖特性和已有的人工繁殖方法进行了综述, 并简要介绍在其种苗繁殖研究方面取得的进展。其中利用播种繁殖成功的物种有12种, 共繁殖230,000株种苗; 利用扦插繁殖成功的物种有5种, 共繁殖33,100株种苗; 华盖木(Manglietiastrum sinicum)、河北梨(Pyrus hopeiensis)和黄梅秤锤树(Sinojackia huangmeiensis)采用嫁接繁殖出了2,415株种苗; 9个物种的组织培养技术获得成功, 共繁殖了24,850株种苗。这些种苗有些已应用于迁地保护和自然回归。上述研究结果为这14种极小种群野生植物的保护和利用提供了理论和技术基础, 也能为其他极小种群野生植物的保护和利用提供参考。     

扦插时间对蝟实插穗生根率和相关指标的影响及生根效应综合评价

在3月5日至9月5日期间,以蝟实( Kolkwitzia amabilis Graebn.)顶端枝条作为插穗,每隔10 d扦插1次,对扦插10 d后插穗的生根率,内源吲哚乙酸( IAA)、脱落酸( ABA)和赤霉素( GA3)含量,超氧化物歧化酶( SOD)、过氧化物酶( POD)和过氧化氢酶( CAT)活性以及可溶性糖和可溶性蛋白质含量进行比较,对生根率与上述8项指标进行相关性分析和回归分析,并对这8项指标进行主成分分析;在此基础上,对不同扦插时间插穗的生根效应进行隶属函数值分析和综合评价。结果显示：随扦插时间推移,蝟实插穗的生根率总体上呈现先升高后降低的变化趋势,5月下旬至7月中旬期间扦插的插穗生根率相对较高,并以6月中旬至7月中旬期间扦插的插穗为最高,总体在70%以上。随扦插时间推移,插穗中IAA和可溶性糖含量均呈波动变化趋势;而插穗中的ABA含量、POD活性和可溶性蛋白质含量总体呈先逐渐升高后逐渐降低的趋势,GA3含量和CAT活性变化不明显,SOD活性总体上呈缓慢升高的趋势。相关性分析结果表明：蝟实插穗的生根率与IAA含量、POD活性和可溶性蛋白质含量呈极显著(P<0.01)正相关,与CAT活性呈极显著负相关。主成分分析结果显示：前2个主成分的累计贡献率为84.383%,说明前2个主成分能够基本反映蝟实扦插生根的主要影响因子,其中第1主成分中可溶性蛋白质和IAA含量为主要因子,第2主成分中CAT活性为主要因子。综合评价结果显示：5月下旬至7月中旬期间扦插的蝟实插穗的综合评价指数(D)较高,为0.747~0.983,与插穗生根率的实测值基本吻合。研究结果表明：在中国西北地区,蝟实插穗的适宜扦插时间为5月下旬至7月中旬,并以6月中旬至7月中旬为最佳;扦插过程中喷施适当浓度IAA溶液可以提高插穗的生根率。     

IBA浓度、扦插时间对江西杜鹃和百合花杜鹃扦插生根的影响

为探明有鳞大花亚组杜鹃扦插生根的最佳IBA浓度和扦插时间,该研究以江西杜鹃、百合花杜鹃为材料,分别采用腐叶土+河沙(1:1)、泥炭+珍珠岩+蛭石(3:1:1)基质,开展了4个IBA浓度和4个扦插时间的生根试验.结果表明:IBA浓度对除老叶留存数外的所有指标有显著影响,其中100 mg·L-1 IBA处理生根率、新梢长最大,腐烂率最低,其它指标也表现良好,为最佳生根浓度;50 mg·L-1 IBA处理根幅、新梢率最大,但不定根数最少,效果其次;200 mg·L-1 IBA处理促进根系生长,但生根率较低、特别是显著抑制新梢发育;对照处理生根效果最差.扦插时间对所有生根指标均有显著影响,早春(04-18)木质化硬枝扦插除老叶留存数较差外,其它指标均表现极佳,为最适扦插时间;秋季(10-19)半木质-木质化过渡枝扦插效果其次;夏季(06-21)嫩枝及(08-16)半木质化枝生根效果极差,不宜进行扦插育苗.物种、基质对生根指标也有显著影响,百合花杜鹃扦插生根能力强于江西杜鹃,泥炭+珍珠岩+蛭石(3:1:1)基质生根效果优于腐叶土+河沙(1:1).该研究结果首次发现早春新梢萌发前采用木质化硬枝扦插可以显著提高两种杜鹃的生根效果,为该亚组杜鹃的扦插育苗提供了科学依据.     

Refuse attracts? Effect of refuse dumps of leaf‐cutting ants on floral traits

The nutrient‐rich organic waste generated by ants may affect plant reproductive success directly by enhancing fruit production but also indirectly, by affecting floral traits related with pollinator attraction. Understanding how these soil‐nutrient hot spots influence floral phenotype is relevant to plant–pollination interactions. We experimentally evaluated whether the addition of organic waste from refuse dumps of the leaf‐cutting ant Acromyrmex lobicornis (Hymenoptera: Formicidae: Attini) alters floral traits associated with pollinator attraction in Eschscholzia californica (Ranunculales: Papaveraceae), an entomophilous herb. We analysed flower shape and size using geometric morphometric techniques in plants with and without the addition of refuse‐dumps soil, under greenhouse conditions. We also measured the duration of flowering season, days with new flowers, flower production and floral display size. Plants growing in refuse‐dumps soil showed higher flower shape diversity than those in control soil. Moreover, plants in refuse‐dumps soil showed bigger flower and floral display size, longer flowering season, higher number of flowering days and flower production. As all these variables may potentially increase pollinator visits, plants in refuse‐dumps soil might increase their fitness through enhanced attraction. Our work describes how organic waste from ant nests may enhance floral traits involved in floral attraction, illustrating a novel way of how ants may indirectly benefit plants.     

湖北省九华山林场不同树种配置杉阔混交林林分空间结构特征分析

以三种(杉木+少量栎类、杉木+栎类+光皮桦、杉木+栎类+光皮桦+马尾松)不同树种配置的杉阔混交林为研究对象,计算了角尺度、大小比数、混交度三个林分空间结构指标,全面分析了湖北省九华山林场不同树种配置杉阔混交防护林林分空间结构特征,结果表明:优势树种主要有杉木(Cunninghamia lanceolata(Lamb.)Hook.)、栎类(Quercus L.)及光皮桦(Betula luminifera)三种,并有少量马尾松(Pinus massoniana)散生于林内,生长优势也较弱。不同树种配置所呈现的林分空间结构也不相同。树种配置Ⅰ(杉木+少量栎类)的角尺度平均值为0.42,大小比数平均值为0.31,混交度平均值为0.18,林木空间分布格局和生长优势度均较好,但混交程度较弱,近乎杉木纯林,对应的生物多样性也会较小。树种配置Ⅱ(杉木+栎类+光皮桦)的角尺度平均值为0.5,大小比数平均值0.32,混交度平均数0.48,空间分布格局整体呈现随机分布;林木主要处于亚优势生长状态,混交度以中度-强度混交为主;而树种配置Ⅲ(杉木+栎类+光皮桦+马尾松)的角尺度平均值为0.58,大小比数平均值0.51,混交度平均数0.54,林木空间格局呈现聚集分布,生长优势水平中庸,为中度混交。全面分析林分空间结构,可以明确林分空间结构中存在的不合理情况,为合理择伐以及近自然经营提供科学依据,使该地区的杉阔混交林的多种功能得到可持续发挥。