浅谈HACCP在机制针形名茶中的应用

对HACCP作简要介绍，根据HACCP体系的要求，分析了机制针形名茶过程中各个环节可能出现的危害因素，用HACCP的原理确立了关键控制点，并且建立了相应的控制措施。     

变叶海棠种群多样性的形成与分化研究

 采用杂种指数和形象化散点图法, 探明了变叶海棠以兼性无融合生殖方式与陇东海棠和花叶海棠产生渗入杂交变异, 又以无融合生殖方式保持新产生变异的遗传, 经过数千万年的世代繁衍,形成现今这样极其复杂多样的渗入杂交群体, 该群体为3 个种的杂交复合体。由于杂种的全部或部分能育子代中发生的基因重组和增加基因的突变, 丰富了物种的基因库, 从而深入的揭示了变叶海棠具有多种高抗性的遗传机理。在变叶海棠居群内保护或栽植适量的陇东海棠和花叶海棠, 对于保持和促进变叶海棠多样性的形成与分化具有重要意义。     

萝卜离体再生的影响因素

对影响萝卜离体再生的因素进行了研究,结果表明,不同基困型材料均以带柄子叶的再生频率最高;不同基因型材料所需的最适激素浓度和配比不同,在一定范围内提高6-BA浓度可促进不定芽的分化;苯基脲类细胞分裂素TDZ与嘌呤型细胞分裂素6-BA和KT相比,对促进萝卜不定芽分化的效果更好;AgNO_3可显著提高不定芽再生频率;NAA诱导生根的效果优于IAA。     

Second round of an interlaboratory comparison of SARS-CoV2 molecular detection assays used by 45 veterinary diagnostic laboratories in the United States

The COVID-19 pandemic presents a continued public health challenge. Veterinary diagnostic laboratories in the United States use RT-rtPCR for animal testing, and many laboratories are certified for testing human samples; hence, ensuring that laboratories have sensitive and specific SARS-CoV2 testing methods is a critical component of the pandemic response. In 2020, the FDA Veterinary Laboratory Investigation and Response Network (Vet-LIRN) led an interlaboratory comparison (ILC1) to help laboratories evaluate their existing RT-rtPCR methods for detecting SARS-CoV2. All participating laboratories were able to detect the viral RNA spiked in buffer and PrimeStore molecular transport medium (MTM). With ILC2, Vet-LIRN extended ILC1 by evaluating analytical sensitivity and specificity of the methods used by participating laboratories to detect 3 SARS-CoV2 variants (B.1; B.1.1.7 [Alpha]; B.1.351 [Beta]) at various copy levels. We analyzed 57 sets of results from 45 laboratories qualitatively and quantitatively according to the principles of ISO 16140-2:2016. More than 95% of analysts detected the SARS-CoV2 RNA in MTM at ≥500 copies for all 3 variants. In addition, for nucleocapsid markers N1 and N2, 81% and 92% of the analysts detected ≤20 copies in the assays, respectively. The analytical specificity of the evaluated methods was >99%. Participating laboratories were able to assess their current method performance, identify possible limitations, and recognize method strengths as part of a continuous learning environment to support the critical need for the reliable diagnosis of COVID-19 in potentially infected animals and humans.     

Paspalines C–D and Paxillines B–D: New Indole Diterpenoids from Penicillium brefeldianum WZW-F-69

Five new indole diterpenoids named paspaline C–D (1–2) and paxilline B–D (3–5), as well as eleven known analogues (6–16), were identified from fungus Penicillium brefeldianum strain WZW-F-69, which was isolated from an abalone aquaculture base in Fujian province, China. Their structures were elucidated mainly through 1D- and 2D-NMR spectra analysis and ECD comparison. Compound 1 has a 6/5/5/6/6/8 hexacyclic ring system bearing 2,2-dimethyl-1,3-dioxocane, which is rare in natural products. Compound 2 has an unusual open F-ring structure. The cytotoxic activities against 10 cancer cell lines and antimicrobial activities against model bacteria and fungi of all compounds were assayed. No compound showed antimicrobial activity, but at a concentration of 1 μM, compounds 1 and 6 exhibited the highest inhibition rates of 71.2% and 83.4% against JeKo-1 cells and U2OS cells, respectively.     

柑桔体细胞杂种的花粉育性及其遗传稳定性

对原生质体融合产生的５个已开花的体细胞杂种的花粉育性观察表明，它们的花粉染色活力在０－９０．１８％之间。其中４个体细胞杂种的花粉育性介于双亲之间，偏向高值亲本；种间异源四倍体体细胞杂种产生７．１８％－１８．５９％的小花粉，这类花粉只有正常花粉粒的１／３左右大小、内空。脐橙与红桔的体细胞杂种不产生花粉。墨西哥来檬与伏令夏橙的体细胞杂种花粉育性稳定，年份间无显著差异；粗柠檬与哈姆林甜橙的体细胞杂种无性繁殖后代之间，花粉育性无显著差异。     

以控制木虱为重点的柑橘黄龙病综合防治技术研究

柑橘黄龙病是全株系统性发生的毁灭性病害，目前尚无有效的治疗药剂和有效的给药方法，感病后只有挖掉，以免传染，所以俗称柑橘上的癌症。根据桂林市2004年底的调查，全市危害最轻的县病株率达5%，危害最重的县病株率已达到40％～50%。目前该病和其传媒昆虫一柑橘木虱在全广西都有分布，已成为广西的优势产业-柑橘业发展的最大障碍。植物检疫、种植无病苗木、清除病树、防治柑橘木虱等4条综合防治柑橘黄龙病的措施在20世纪60年代就已提出，在70年代末80年代初又加了“隔离种植、加强栽培管理”。     

不同温度下东方粘虫年龄-阶段两性实验种群生命表的构建

为明确不同温度对东方粘虫Mythimna separata(Walker)种群动态的影响,建立东方粘虫种群动态模型,利用年龄-阶段两性种群生命表得到了室内不同温度下东方粘虫种群的发育历期、存活率、繁殖力和种群生命表参数,并基于种群生命表参数预测了2个月内东方粘虫的种群动态。结果表明,东方粘虫各虫态的发育历期和产卵前期随温度的升高而显著缩短。24℃下,东方粘虫单雌平均产卵量为717.1粒,显著高于其它温度下;成虫寿命也显著高于其它温度下,且雄蛾寿命显著长于雌蛾,分别为15.3 d和13.0 d;卵孵化存活到成虫的概率、幼虫存活率和化蛹率均最高,分别为66.7%、68.9%和96.8%。内禀增长率随温度的升高而显著增加,平均世代周期则显著降低,18、21、24、27、30℃下分别为0.051、0.077、0.113、0.121、0.156 d-1和77.2、61.3、49.0、40.3、31.5 d;周限增长率也随温度的升高而增加,分别为1.05、1.08、1.12、1.13、1.17 d-1;净增殖率在24℃下为257.1,显著高于其它温度下,其它温度条件下无显著差异。表明东方粘虫在18~30℃范围内都能完成生长发育和生殖,24℃下种群存活率高、繁殖力大、世代周期较短,更适合种群增长。     

不同温度下番石榴实蝇在芒果上的生长发育及存活率

本试验在室内17~35℃的固定温度下对番石榴实蝇的生长发育、成虫羽化时间及存活率等生物学习性进行了初步研究。结果表明,在17~32℃,随着温度逐渐升高,番石榴实蝇卵、幼虫和蛹的历期逐渐缩短,但35℃时的历期比32℃时有所延长;在23~32℃,随着温度升高,成虫产卵前期逐渐缩短。卵、幼虫、蛹和成虫产卵前期的发育起点温度分别为12.18、7.13、11.75和12.85℃;有效积温分别为20.16、124.11、155.50和339.09日·度。成虫羽化时间从黎明持续至黄昏,在较低和较高的温度下,成虫大多集中在上午羽化,而在23~26℃下,成虫全天羽化时间比较均衡,在正午前后羽化更多。在20~32℃,从卵发育至成虫的总存活率均为70%以上,17℃时为56.15%,35℃时仅为28.56%。     

凤尾菇原基形成的细胞学研究

本研究对凤尾菇担孢子萌发至原基形成过程进行显微观察，结果表明，培养２０小时，大多数孢子已经萌发，初生菌丝长至３０μｍ左右开始产生分枝，但无锁状联合，有的初生菌丝能形成原垣孢子、培养约６天、两条初生菌丝通过顶端细胞或其他部位融合，发育成具有顶端分生孢子和锁状联合的次生菌丝体，培养２２天，大量次生菌丝的中部相互扭结，形成半球形的原基。