Rapid Analysis of Four Alkaloids in <i>Uncaria rhynchophylla</i> by Core-Shell Column HPLC and Quantitative Analysis of Multi-Components by Single Marker (QAMS)

As a traditional herbal medicine, the major alkaloids in Uncaria rhynchophylla have been proven to have blood pressure-lowering and sedative effects. It is essential to develop an effective method for the determination of the major alkaloids in U. rhynchophylla. In this research, a rapid quantitative analysis involving multi-components analysis by a single marker strategy coupled with core-shell column HPLC was adopted to analyse four alkaloids (corynoxeine, isocorynoxeine, isorhynchophylline, rhynchophylline) in U. rhynchophylla. Isorhynchophylline was selected as the internal reference substance, the content of which was determined by the traditional external standard method. Relative correction factors (RCF) between isorhynchophylline and the other three alkaloids were calculated respectively. The results showed that the QAMS method had good robustness under different HPLC instruments. Nineteen batches of U. rhynchophylla were tested. No significant difference was observed between the results by QAMS and EMS (Correlation coefficient > 0.99, p > 0.05). The QAMS method could be employed as a rapid, effective technique for the quality control of U. rhynchophylla.     

A Rapid Determination of 30 Prohibited Pesticide Residues in Lycii Fructus by UPLC-MS/MS

Prohibited pesticide residues have become one of the main factors affecting the quality and safety of Lycii Fructus, However, rarely studies focus on the rapid determination of these residues. Here, a total of 30 kinds of prohibited pesticide residues were determined by ultra-performance liquid chromatography tandem triple quadrupole mass spectrometry (UPLC-MS/MS) in five different process ways. Pretreatment methods, chromatographic separation and detection conditions in mass spectrometry were all optimized accordingly. Among the five different pretreatment methods, the first and third solid phase extraction failed to provide high recoveries of sulfosulfuron compounds (both lower than 60%). Recovery of chlorphenamidine by the Quick Easy Cheap Effective Rugged and Safe multiresidue method (QuEChERS) was lower than 60%, which did not meet the requirements of trace determination. The concentrations of 30 prohibited pesticides residues treated by straightforward and solid phase extraction showed good linearity in their corresponding ranges, with correlation coefficients over 0.99. The average recoveries of straightforward ranged from 78.13% to 110.9%, while RSD ranged from 1.3% to 16.9%, albeit poor purification was observed. The recovery yield from solid phase extraction was between 67.75% and 103.08% with RSD value from 0.8% to 14.0%, which met the requirements of trace determination, this method has good precision and stability. These results could be employed to other Traditional Chinese Medicines (TCMs) in detecting prohibited pesticide residues.     

Investigation of <i>GhFAT</i> Genes Related to Seed Oil Content and Fatty Acid Composition in <i>Gossypium hirsutum</i> L.

Fatty Acyl-ACP thioesterase (FAT) is a key enzyme controlling oil biosynthesis in plant seeds. FATs can be divided into two subfamilies, FATA and FATB according to their amino acid sequences and substrate specificity. The Upland cotton genome contains 20 GhFAT genes, amongst which 6 genes were of the GhFATA subfamily and 14 of the GhFATB subfamily. The 20 GhFAT genes are unevenly distributed on 14 chromosomes. The GhFATA genes have 5 or 7 exons and the GhFATB genes have 6 or 7 exons. All GhFAT proteins have the conserved Acyl-ACP_TE domain and PLN02370 super family, the typical characteristics of plant thioesterases. Analyses of the expression level of GhFATs and the compositions of fatty acid in 5–60 days-post-anthesis seeds showed that the ratio of saturated fatty acids to unsaturated fatty acids was consistent with the expression profile of GhFATB12, GhFATB3, and GhFATB10; the ratio of monounsaturated fatty acid to polyunsaturated fatty acids was consistent with the expression profile of GhFATA3. The oil contents of mature cottonseeds were positively correlated with the contents of palmitic acid and linolenic acid as well as seed vigor. These results provide essential information for further exploring the role(s) of the specific GhFATs in determining oil biosynthesis and cottonseed compositions.     

青藏高原垫状点地梅叶际及内生可培养微生物多样性

【背景】垫状点地梅作为青藏高原最具代表性的垫状植物,其叶际和内生微生物对适应极端环境有重要意义,同时也是一种独特的资源。【目的】探究垫状点地梅叶际和叶内可培养微生物多样性,以及不同生存状态个体之间的微生物差异。【方法】采用纯培养方法分离和纯化3个不同地区垫状点地梅叶际和叶内的细菌、酵母菌和丝状真菌,并用16S rRNA基因和ITS区域序列进行分析鉴定。【结果】最终得到叶际微生物350株,鉴定为22属49种,优势种为Penicillium sajarovii;内生微生物274株,鉴定为19属45种,优势种为Bacillusmycoides;两者的优势属均为Penicillium。垫状点地梅叶际和叶内之间及不同生存状态个体之间微生物的α多样性大多无显著差异,各群落间的成员也有重叠,但物种组成存在显著的空间异质性。【结论】垫状点地梅叶际和叶内有着丰富的可培养微生物资源,来源于不同生存状态的个体或不同部位的微生物物种组成差别较大,微生物对不同环境的选择偏好形成了不同的群落模式。但这些不同来源的微生物群落之间同样存在高比例的共有菌株,这些共有菌株的异养方式和生态位并不固定,可兼共生和腐生生存,生...     

Interactive Effects of Iron and Photoperiods on Tomato Plant Growth and Fruit Quality

Journal of Plant Growth Regulation - Photoperiod and micronutrient iron (Fe) are critical for plant growth and development. However, the interactive effects of Fe nutrition and photoperiod on...     

基于叶绿体基因组数据的芸香科属间系统发育初步分析（专题约稿）

该研究在人工控制水分条件下,设置3个干旱胁迫处理,选用3个主栽油菜品种‘陇油10号’、‘陇油2号’、‘青杂5号’幼苗进行盆栽试验,测定干旱胁迫条件下叶片相对含水量、叶绿素含量、光合气体交换参数及叶绿素荧光参数等指标,考察各指标在干旱胁迫过程中的变化特征,并通过主成分分析(PCA)和隶属函数法评价品种的抗旱性及其主要响应因子,以揭示西北地区油菜幼苗响应干旱胁迫的光合调控机制。结果表明：(1)各品种油菜幼苗的叶片相对含水量(RWC)均随干旱胁迫程度的递增而逐渐降低,最大水分亏缺(WSD)却逐渐上升。(2)各品种油菜幼苗叶片的叶绿素a含量、叶绿素总含量随着干旱胁迫程度的递增而先增加后递减,且同一种幼苗在不同处理间差异显著。(3)各品种油菜幼苗叶片的净光合速率(P_n)、水分利用效率(WUE)、单株生物量、气孔导度(G_s)、胞间CO₂浓度(C_i)均在受到干旱胁迫时迅速降低,且同一品种幼苗在不同处理间差异显著,而其叶片蒸腾速率(T_r)在干旱胁迫下无显著变化。(4)各品种油菜幼苗叶片光化学猝灭系数(qP)和非光化学猝灭系数(NPQ)随着干旱胁迫程度的递增先增加后递减,最大光化学效率(F_v/F_m)和电子传递速率(ETR)在受到干旱胁迫时迅速降低,且同一品种幼苗在不同处理间差异显著。(5)主成分分析结果表明,在油菜幼苗受到干旱胁迫时RWC、C_i、G_s、P_n、WUE、叶绿素总含量、叶绿素a含量和NPQ起主要调控作用;隶属函数法综合评价表明,3个品种油菜幼苗耐旱能力由高到低依次为‘陇油10号’＞‘陇油2号’＞‘青杂5号’。     

声学指数在城市森林鸟类多样性评估中的应用

鸣声是鸟类之间进行沟通和传递信息的重要方式,这为通过声学监测评估鸟类多样性提供了独特的机会。利用声学指数快速评估生物多样性是一种新兴的调查方法,但城市森林中的复杂声环境可能会导致声学指数的指示结果出现偏差。为了解声学指数在城市森林中应用的可行性,本研究在北京市东郊森林公园设置了50个矩阵式调查样点,于2021年4–6月每月进行1次鸟类传统观测和同步鸣声采集,通过比较两种方法的结果来探究声学监测的有效性。采用Spearman相关分析和广义线性混合模型评估6个常用声学指数与鸟类丰富度和多度的关系,并衡量了每个指数的性能。结果表明:(1)本研究共记录到鸟类10目23科35种,通过声学监听识别的总物种数与传统鸟类观测相等,但具体鸟种存在差异;(2)不同月份间声学指数与鸟类丰富度和多度的相关性有明显差别,声学复杂度指数(ACI)和标准化声景差异指数(NDSI)优于其他指数,是评估鸟类多样性的关键变量;(3)声学指数对鸟类多度的预测能力(R²m=0.32,R2c=0.80)要高于丰富度(R²m=0.12,R2c=0.18)。声学指数为快速评估生物多样性提...     

固相萃取与气相色谱⁃质谱法联用测定食用植物油和含脂肪食品中氯丙醇酯的方法验证研究

氯丙醇酯是国际上广泛关注的食品加工过程污染物,其水解产物氯丙醇对人体（特别是婴幼儿）危害风险较大。采用固相萃取与气相色谱-质谱（gas chromatography-mass spectrometry,GC-MS）联用技术,对食用植物油和含脂食品中的氯丙醇酯[3-氯-1,2-丙二醇脂肪酸酯（简称3-MCPD酯）和2-氯-1,3-丙二醇脂肪酸酯（简称2-MCPD酯）]进行检测。该方法准确度高（3-MCPD酯和2-MCPD酯的平均回收率分别为98.9%和96.5%)、灵敏度高(3-MCPD酯和2-MCPD酯的检出限分别为0.042 mg·kg^-1和0.058 mg·kg^-1)、重现性好(相对标准偏差均低于5%)。76批次监测样品中,3-MCPD酯和2-MCPD酯的含量分别为0.042~4.865 mg·kg^-1(平均值为0.773 mg·kg^-1)和0.058~2.592 mg·kg^-1(平均值为0.469 mg·kg^-1)。经机构间的协同验证和英国FAPAS样的能力验证,2种氯丙醇酯在0.200~3.000 mg·kg^-1范围内线性良好,为进一步研究奠定了基础,同时也为食品加工企业严格控制生产过程建立了一种可行的检测方法。     

Preparation and Characterization of a Silk Fibroin/Polyurethane Fiber Blend Membrane Containing Actinomycin X2 with Excellent Mechanical Properties and Enhanced Antibacterial Activities

Development of suitable antimicrobial biomaterials for hygienic wound dressing and healing is an important requirement for medical application. Durable mechanical properties increase the application range of biomaterial in different environmental and biological conditions. Due to the inherent brittleness of silk fibroin (SF), polyurethane fiber (PUF) was used to modify SF containing actinomycin X2 (Ac.X2) to prepare silk fibroin@actinomycin X₂/polyurethane fiber (ASF/PUF) blend membranes. The ASF/PUF blend membrane was developed by solution casting method. Incorporation of PUF improved the flexibility of material and introduction of Ac.X2 has increased antibacterial activity of materials. Excellent mechanical properties (tensile strength up to 25.7 MPa and elongation at break up to 946.5 %) of 50 % SF+50 % PUF blend membrane were proved by tensile testing machine. FT-IR spectra, TGA, contact angle and DMA were tested to prove the blend membrane's physico-chemical characteristics. ASF/PUF blend membrane displayed satisfactory antibacterial activity against S. aureus, and the cytotoxicity tests showed that the blend membrane has better biosafety compared to directly applied Ac.X2 in soluble form. These results suggest that the modification of SF through PUF for development of flexible antibacterial membranes has great potential application value in the field of silk-like material fabrication.