正交设计优化微波辅助测定延胡索叶总生物碱含量

通过微波辅助提取的方式,以延胡索叶总生物碱含量为考察指标,通过单因素试验和正交试验对总生物碱提取方法进行优化。重点考察了微波提取温度、时间、料液比、提取缓冲液pH值等因素对延胡索叶总生物碱得率的影响。各因素对延胡索叶总生物碱提取量的影响大小依次为:提取缓冲液pH值料液比提取温度。其最佳的提取方法为:提取缓冲液pH值为1. 0,料液比1∶100,提取温度60℃,提取时间20 min。在此条件下,叶总生物碱含量为25. 910 mg/g。利用微波辅助提取延胡索叶中总生物碱,不仅耗时短,效率高,而且操作简单、稳定,为延胡索叶总生物碱含量测定提供一定的技术支持。     

Elevated rates of positive selection drive the evolution of pestiferousness in the Colorado potato beetle (Leptinotarsa decemlineata,Say)

Contextualizing evolutionary history and identifying genomic features of an insect that might contribute to its pest status is important in developing early detection and control tactics. In order to understand the evolution of pestiferousness, which we define as the accumulation of traits that contribute to an insect population's success in an agroecosystem, we tested the importance of known genomic properties associated with rapid adaptation in the Colorado potato beetle (CPB), Leptinotarsa decemlineata Say. Within the leaf beetle genus Leptinotarsa, only CPB, and a few populations therein, has risen to pest status on cultivated nightshades, Solanum. Using whole genomes from ten closely related Leptinotarsa species native to the United States, we reconstructed a high‐quality species tree and used this phylogenetic framework to assess evolutionary patterns in four genomic features of rapid adaptation: standing genetic variation, gene family expansion and contraction, transposable element abundance and location, and positive selection at protein‐coding genes. Throughout approximately 20 million years of history, Leptinotarsa species show little evidence of gene family turnover and transposable element variation. However, there is a clear pattern of CPB experiencing higher rates of positive selection on protein‐coding genes. We determine that these rates are associated with greater standing genetic variation due to larger effective population size, which supports the theory that the demographic history contributes to rates of protein evolution. Furthermore, we identify a suite of coding genes under positive selection that are putatively associated with pestiferousness in the Colorado potato beetle lineage. They are involved in the biological processes of xenobiotic detoxification, chemosensation and hormone function.     

A new linkage group involved in sex determination in haplotilapiine cichlids

The high diversity of sex chromosomes and sex determination systems among haplotilapiines suggests that this large cichlid clade is a good model for investigating the evolution of genetics of sex determination. Nonetheless, information about sex determination in this clade remains sparse. The present study reports a microsatellite marker that is closely associated with sex in Xenotilapia rotundiventralis from Lake Tanganyika, Africa. This study is the first to suggest the role of linkage group 17 in sex determination in haplotilapiine cichlids.     

高速逆流色谱法制备灵芝萜烯酮醇

本研究建立一种从灵芝子实体提取物中快速制备灵芝萜烯酮醇的方法。以沪农灵芝1号子实体为原料,经乙醇提取、D101大孔树脂富集后,再经一次正相色谱柱层析,获得富含灵芝萜烯酮醇的流分。采用高速逆流色谱法对该流分进行分离,优化分离条件,获得的最佳条件为：溶剂体系为正己烷-乙酸乙酯-甲醇-水（V/V/V/V,12:24:18:9）,流速2.0mL/min,转速900r/min,上样量500mg,一次上样可得到纯度为90.9%的灵芝萜烯酮醇52.1mg,得率达到10.4%。该方法具有操作简单、污染小、成本低、得率和纯度高的特点,是规模化制备灵芝萜烯酮醇的一种新方法。     

基于纳米孔测序技术的柑橘黄龙病检测方法建立

柑橘黄龙病(Huanglongbing)是柑橘生产上最具毁灭性的病害,及时快速地进行早期检测和诊断是防控黄龙病的关键措施之一.本文利用掌上纳米孔测序仪MinION对携带黄龙病菌Candidatus Liberibacter asiaticus的DNA样品进行测序,并利用Blast、GraphMap、minimap2以及两种bwa的比对方法将测序结果比对到黄龙病菌基因组上,比对结果均匀的比对到黄龙病菌基因组上,并未发现严重的偏倚现象,验证了其测序结果的可靠性.本技术可弥补因柑橘木虱Diaphorina citri(Kuwayama)虫体过小或损坏难以进行光学识别的不足,并可同时检测虫体是否携带有黄龙病菌,对有黄龙病发生风险但尚未有黄龙病实际发生的柑橘种植区提供实时实地的监控与预警.     

春尺蠖蛹雌雄外部形态特征快速鉴别分析

为依据春尺蠖Apocheima cinerarius Erschoff蛹的形态特征快速、无损、准确鉴别雌雄个体,对其头部、胸部、腹部和体色外部鉴别特征进行了分析,并通过解剖生殖系统验证准确性.结果表明:以春尺蠖蛹的胸部和腹部特征识别雌雄准确率明显高于头部和体色特征,识别率可达100％.首先,雌蛹第8腹节腹板前缘中部具有"Y"型沟,与第7腹节腹板后缘形成倒三角状,而雄蛹无此特征.其次,雌蛹生殖孔与产卵孔连接形成裂缝,两侧平坦无突起,而雄蛹第9腹节腹板中央有一纵裂缝的生殖孔,两侧各有半圆状瘤状突起.最后,雌蛹的胸部背板各节间相对长度均小于雄蛹,而雄蛹中胸背板最宽,其后缘明显向外凸起.因此,春尺蠖蛹胸部或腹部特征可用于快速、准确地鉴别雌雄性别.     

兰州兴隆山土壤微生物的分布及其相关特性分析

目的以兰州兴隆山不同区域的土壤微生物为研究对象,分析比较土壤微生物数量与土壤酶活性之间的相关性。方法利用不同方法测定土壤理化性质、微生物数量以及土壤相关酶活特性;采用三区划线法进行土壤微生物的分离与纯化,通过16S rDNA和ITS方法进行优势菌株鉴定。结果兰州兴隆山土壤中微生物菌群数量由多到少依次为细菌、放线菌、真菌。通过分离纯化后,对其中的2株优势菌进行了鉴定,初步推断X2为萎缩芽胞杆菌属(Bacillus atrophaeus)细菌,Z2为栎生青霉属(Penicillium glandicola)真菌。从酶活特性可知,阳面的土壤过氧化氢酶活性比阴面高;随着海拔高度的增加,过氧化氢酶活性呈现增加趋势;阳面的土壤脱氢酶活性总体比阴面高,并且随着海拔梯度的升高,土壤脱氢酶活性也在不断升高。从相关性分析可知,不同海拔土样间微生物数量与酶活性之间表现出明显的相关性。结论兰州兴隆山土壤微生物数量丰富,且细菌数量居多;不同阴、阳面土壤微生物的层次分布以及活性也各有不同。以上研究可为兰州兴隆山土壤生态系统演替等提供参考依据,并为土壤生态环境的治理做铺垫。