虎雪兰玻璃化超低温法脱毒技术的研究

以兰属花卉虎雪兰组培原球茎为试材,采用玻璃化超低温法对兰花病毒脱除进行了研究,以期为虎雪兰玻璃化超低温法脱毒体系的建立提供参考依据。结果表明:在蔗糖浓度0.5 mol·L-1预培养4 d,然后在蔗糖0.6 mol·L-1加载液冰上处理50 min,之后转入PVS2溶液冰上玻璃化处理120 min,再液氮冷冻40 min,37℃水浴解冻3 min,最后卸载液(1/2MS+1.2 mol·L-1蔗糖)卸载20 min,待恢复培养后,原球茎成活率可达到65%以上,随机检测不同处理样品的脱毒率可达97%。     

Review of doubled haploid production in durum and common wheat through wheat × maize hybridization

Production of doubled haploids (DHs) is an important methodology to speed the process of breeding and development of mapping populations in crops. The procedure for DH production includes two major steps: haploid induction and chromosome doubling. In recent years, wide hybridization between wheat and maize has become a main approach for haploid production in wheat. In this method, the maize chromosomes are completely eliminated during the early development of the hybrid seeds after wheat spikes were pollinated with maize pollen. Numerous wheat cultivars and mapping populations have been developed using wheat–maize hybridization. In this study, we review the procedures of DH production of durum and common wheat via wide hybridization with maize, the factors which affect the efficiency of DH production, and the mechanism of selective elimination of the maize genome during the early development of the hybrid embryos. We also report a highly efficient protocol for DH production in durum and common wheat, which was established based on the optimal conditions for each of the factors that affect the efficiency of DH production.     

敌百虫在乌鳢体内和水环境中的代谢动力学及残留研究

[目的]明确敌百虫在水产养殖中的安全性。[方法]全池泼洒0.5 mg/L敌百虫,采用气相色谱法测定敌百虫在乌鳢体内的代谢动力学和残留消除规律。[结果]乌鳢组织和水样中敌百虫的最低检测限为0.02μg/m L。随着时间的延长,敌百虫在乌鳢血液中的浓度逐渐升高,120 h达最高,为0.072 mg/kg,至360 h时未检出。肌肉中12 h内未检出,24 h浓度为0.023 mg/kg,120 h检出最大浓度0.051 mg/kg,至288 h未检出。肝脏8 h未检出,12 h检出浓度为0.026 mg/kg。使用敌百虫后,乌鳢体内的药物残留量均低于我国的兽药最高残留限量要求,但在养殖水体中的残留时间较长,降解半衰期为35.19 h。[结论]为确保敌百虫使用后对水生态环境及食品安全,建议敌百虫使用后的休药期为150℃·d。     

苹果脱毒技术研究进展

苹果（Malus pumila Mill.）普遍感染病毒。目前, 培育无病毒原种母本树, 建立用于繁殖接穗和营养系砧木的母本园, 栽植无病毒苗木, 是防治病毒病的根本措施。本文针对常见的4 种苹果病毒及1 种类病毒, 综述了茎尖培养、热处理、化学处理、微茎尖嫁接以及低温处理脱除苹果病毒方法的研究进展, 分析了不同方法的应用效果, 及所适合脱除的病毒种类, 以期为我国苹果病毒脱除技术研究提供参考信息。     

Study on Florfenicol-resistant Induction in vitro and Changes of Drug Sensitivity of Swine E.coli O157:H7

To preliminary investigate the mechanism of drug resistance and drug-resistant elimination of swine E.coli O157:H7,sub-inhibitory concentration in vitro drug-induced method was used in this study,for inducing two strains of E.coli O157:H7 becoming florfenicol highly resistant strains,and eliminated florfenicol resistance of florfenicol-resistant strains by continuous cultured without florfenicol pressure.The drug sensitivity and resistant genes of florfenicol-induced strains and florfenicol-resistance eliminated strains were detected.The results showed that compared with original strains,after drug-resistant induction by florfenicol,swine E.coli O157:H7 were resistant to florfenicol,amoxicillin,cefazolin,cephradine and cephalothin from high sensitivity,and resistant to cefotaxime,ofloxacin,ciprofloxacin and azithromycin from moderate sensitivity.However,after florfenicol-resistance eliminated,swine E.coli O157:H7 restored sensitivity to these drugs.In addition,florfenicol resistance gene,quinolone resistance genes and β-lactamase genes were found in the plasmids of swine E.coli O157:H7,the resistance genes were consistent with the resistance phenotype.According to the results,with the long-term presence of florfenicol pressure,swine E.coli O157:H7 resistant to florfenicol,and acquired penicillins,cephalosporins and quinolones cross-resistance;While swine E.coli O157:H7 was eliminated partial drug-resistance by continuous culture without florfenicol pressure.     

奥运前期北京市一次典型颗粒物生消过程分析

[目的]探讨奥运前期北京市一次典型过程中细颗粒物的生消规律。[方法]利用中国环科院站点的颗粒物在线监测数据、同期气象观测数据,结合美国怀俄明州立大学网上探空资料和数值预报图等,对2008年8月3～11日北京市一次典型颗粒物生消过程进行了分析。[结果]在颗粒物累积过程中,颗粒物呈现逐步老化现象;此次过程主要受大尺度的天气背景影响,且近地面的小风静风、高湿等气象条件不利于污染扩散;持续偏南气流将河北省、天津市及山东的污染物带入北京;混合层高度与温度层结等对污染有重要影响。[结论]该研究为空气污染过程中影响颗粒物生消过程的因素探讨提供理论依据。     

药浴暴露下阿维菌素在异育银鲫体内蓄积和消除规律

采用UPLC-MS/MS法研究了2μg·L-1三次连续水体药浴和6μg·L-1一次性水体药浴条件下阿维菌素在水体中消除、在异育银鲫(Carassius auratus gibelio)体内蓄积和消除变化规律。结果显示,两种药浴暴露方式下阿维菌素在水体中消除呈一级指数衰退消除,消除半衰期(t1/2)均为63 h,240 h时浓度下降到0.5μg·L-1以下。阿维菌素在异育银鲫血浆和肌肉中的含量均呈先升高后下降的趋势,血浆中药物浓度远高于肌肉中的含量。2μg·L-1连续三次药浴组和6μg·L-1一次药浴组血药峰浓度(Cmax)分别为34.97、66.62μg·L-1,其曲线下面积(AUC0-t)分别为9 871.2μg·L-1·h和18 119.6μg·L-1·h;两组药浴肌肉中达峰浓度分别4.42μg·kg-1和15.80μg·kg-1,其AUC0-t分别为641.9μg·kg-1·h和4 271.0μg·kg-1·h。与2μg·L-1连续三次药浴组相比,6μg·L-1一次药浴组阿维菌素在血浆和肌肉中的蓄积作用更加显著。以10μg·kg-1作为阿维菌素在异育银鲫肌肉中最大残留限量,选择95%的置信区间计算异育银鲫肌肉组织中休药期,本研究中2μg·L-1连续三次药浴组肌肉的休药期为295.4 h,6μg·L-1一次药浴组肌肉的休药期为454.5 h。     

电子鼻鉴别白酒信号小波去漂移方法

为提高电子鼻长期鉴别的稳健性,提出了一种基于小波分析的电子鼻信号去漂移方法。对含漂移信号的电子鼻数据进行小波分解,获得分解系数;构造一种相对偏差阈值滤波函数对小波逼近系数进行阈值处理,获得修正的小波系数;运用小波逆变换对修正后的小波系数进行重构,得到去除漂移或少漂移的电子鼻信号。对6种白酒样本随机生成的5组样本训练集与对应的测试集进行去漂移处理与信号重构,提取去漂移处理前后的电子鼻信号积分值特征,并运用Fisher判别分析(FDA)和BP神经网络分别对5组数据集进行鉴别分析。FDA鉴别结果显示,无论是训练集还是测试集,5组样本的鉴别正确率由去漂移前的最高值45%提升至去漂移后的100%。BP神经网络鉴别结果显示,5组样本的鉴别正确率由去漂移前的最高值31.7%提升至去漂移后的98.3%。这说明所给出的去漂移方法在白酒电子鼻的鉴别中是稳健有效的。同时,也为电子鼻鉴别其他物品提供了一种可借鉴的去漂移方法。     

氧氟沙星与左氧氟沙星在中华绒螯蟹体内的药代动力学和残留消除规律研究

以15 mg/kg的剂量分别对中华绒螯蟹(Eriocheir sinensis)单次肌注氧氟沙星和左氧氟沙星,运用反相高效液相色谱法,测定了中华绒螯蟹血淋巴和肌肉、肝胰腺、精巢、卵巢中氧氟沙星和左氧氟沙星的浓度,分别阐明了它们在中华绒螯蟹各组织中的残留消除规律。结果显示,氧氟沙星和左氧氟沙星在中华绒螯蟹血淋巴内的药物-曲线时间关系符合开放性二室模型,其药代动力学方程分别为:Ct=21.31e-0.497t+9.779e-0.035t和Ct=74.938e-1.822t+20.811e-0.038t。氧氟沙星在肌肉、肝胰腺、精巢、卵巢的消除半衰期分别为88.89、65.02、83.26、114.76 h。左氧氟沙星在肌肉、肝胰腺、精巢、卵巢的消除半衰期分别为86.03、344.83、106.19、154.73 h。结果表明,相同给药剂量下,左氧氟沙星在体内浓度更高,分布更广,对于中华绒螯蟹的细菌性疾病有着更好的预防与治疗作用。