Meiotic competence of mouse oocytes reconstructed by replacing the germinal vesicle with a male pronucleus and somatic nucleus

The present study examines the contribution of the nucleus to meiotic competence in mouse oocytes that were reconstructed using nuclear transfer. Three types of reconstructed oocytes were produced: MP‐GV, by transplanting the male pronucleus (MP) into germinal vesicle (GV) stage oocytes; 3T3‐GV, by transplanting the nucleus of a National Institute of Health (NIH) 3T3 cell into a GV stage oocyte; and 3T3‐MII, by transplanting the nucleus of an NIH 3T3 cell into a metaphase II (MII) stage oocyte. The fusion rates differed, but not significantly, in the MP‐GV, 3T3‐GV, and 3T3‐MII groups (77, 63, 56%, respectively). Then, meiotic competence was compared in MP‐GV, 3T3‐GV and non‐manipulated GV stage oocytes as a control. Nuclear envelope breakdown occurred in all the reconstructed oocytes, as well as the control ones. The percentage of first polar body extrusion differed between the MP‐GV (100%), 3T3‐GV (72%), and control (67%) groups. DNA staining with Hoechst 33342 revealed that in the MP‐GV‐group oocytes that had reached MII stage, the chromosomes were condensed and aligned in a regular array similar to the normal metaphase plate. By contrast, in 3T3‐GV group oocytes, the condensed chromosomes were irregularly scattered in the cytoplasm. These results suggest that the donor nucleus affects meiotic competence in reconstructed oocytes.     

基于正交试验的春兰分株繁殖技术优化研究

为优化春兰分株繁殖技术,以NAA为处理试剂,以兰苗成活率为评价指标,采用单因素试验、正交试验优化春兰分株繁殖影响因素。结果表明：影响因素顺序为NAA浸泡时间＞浸泡浓度＞环境温度＞光照强度＞光照时间。根据正交试验K值可得,春兰分株繁殖影响因素最优组合为NAA浸泡浓度0.3mg/L、浸泡时间15min、环境温度21℃、光照强度1000Lx、光照时间10h/d。经验证在此优化因素下,春兰分株繁殖实际成活率高达82.76%。     

1株黄曲霉颉颃菌的鉴定及其抑菌活性成分分析

【目的】筛选黄曲霉颉颃菌,探究其最佳培养条件及有效抗菌成分,为实际生产中应用生物防治方法抑制黄曲霉污染提供新的理论依据。【方法】通过平板对峙法及分子生物学鉴定方法对待测菌株进行筛选鉴定。以抑菌率作为衡量标准,判断所得黄曲霉颉颃菌的最佳培养温度、培养时间、接种量、转速、pH及装液量。通过硫酸铵沉淀法从颉颃菌无菌发酵上清液中提取蛋白,观测粗提物对黄曲霉菌丝生长的影响。通过离子交换色谱和凝胶过滤色谱进一步纯化粗提蛋白,并进行质谱测序及序列对比分析,筛选鉴定颉颃菌产生的有效抑菌成分。【结果】筛选到1株解淀粉芽孢杆菌B10(菌种保藏号CCTCCNO:M2018353)。最佳培养条件为温度40℃,培养时间36 h,接种量3%,转速120 r/min, pH 6.0,装液量30 mL,最大抑菌率可达46.56%。其粗提蛋白能有效抑制黄曲霉生长,破坏菌丝正常形态,并从中筛选出几丁质结合蛋白、壳聚糖酶、葡聚糖酶等8种可能的有效抑菌成分。【结论】本试验分离鉴定出1株抑制黄曲霉正常生长发育的解淀粉芽孢杆菌B10,其产生的多种蛋白成分对黄曲霉有显著抑菌活性。     

Analysis of the seed dispersal patterns of wild soybean as a reference for vegetation management around genetically modified soybean fields

There are concerns that genetically modified soybean might threaten the genetic diversity of the wild soybean populations that are distributed in East Asia because genetically modified soybean has no crossing barrier with wild soybean. A simple and effective method to prevent hybridization via pollen flow is spatial separation between the two species because their hybridization occurs only when they grow in close proximity. Therefore, the invasiveness of wild soybean needs to be known in order to secure the appropriate distances. As wild soybean seeds are dispersed mechanically by pod dehiscence, an experiment was conducted in which white sheets were placed on the ground, concentric circles were drawn around the parent plants, and the number of dispersed seeds within each 0.5 m‐wide zone were counted. About 40% of the produced seeds were dispersed and the number of dispersed seeds gradually declined as the distance from the parent plants increased. The model that explained the relationship between the number and distance of the dispersed seeds was produced by using a generalized linear model procedure. More than 95, 99, and 99.9% of the produced seeds stayed within 3.5, 5.0, and 6.5 m after natural pod dehiscence. Knowing these values is useful for evaluating the level of invasive risk by mechanical seed dispersal. The goal of the work is to efficiently and deliberately prevent hybridization by isolating genetically modified soybean fields and wild soybean populations by vegetation management, including weeding and setting up specific‐width buffer zones.     

商陆抗病毒蛋白在植物抗病上的应用

商陆抗病毒蛋白是指商陆属植物中的核糖体失活蛋白.阐述了商陆抗病毒蛋白的研究历史、意义、种类和理化性质,对病原菌的抗性、抗病机理及其在植物抗病上的应用情况等,并对它的应用前景作了展望.     

一起穿山甲疫情的病原分析

为了查明一起人工养殖穿山甲疫情的致病原因,应用病毒PCR检测和细菌分离的方法对2只前后病死穿山甲进行病原学检测。病毒PCR检测结果显示,未能从肺组织中检测到流感病毒、副黏病毒和腺病毒核酸。细菌分离结果表明,从2只病死穿山甲肺中各分离到1株优势菌株。细菌的生化试验、16S rRNA基因的序列分析表明,2株分离菌株均为摩氏摩根菌。小鼠的致病试验和分离菌的药敏试验结果表明,2株分离菌对小鼠有很强的致病作用,对新霉素、壮观霉素、阿米卡星高度敏感。     

猪繁殖与呼吸综合征病毒感染的诊断及其分子特点

采用流行病学调查、临床症状观察、病理学检查、病毒分离、分离毒株测序以及遗传演化分析的方法,对北京及其周边地区4个猪场剖检的4头猪进行分析。结果:流行病学和临床症状表现为急性高热性传染病;病理学观察为非化脓性脑炎和间质性肺炎等多器官严重的病理变化;RT-PCR和病毒分离确定该疫情的主要病原是猪繁殖与呼吸综合征病毒(PRRSV)。与典型PRRSV感染不同的是:成年猪感染率达50%以上,病死率达80%以上;PRRSV分离株全基因序列分析表明属于PRRSV北美洲型,特别是PRRSV NSP2不连续缺失30个氨基酸,说明此次流行的PRRSV毒株可能为高致病性毒株。     

猪链球菌2型山东强毒株的分离鉴定

对某养猪场发生呼吸道感染及神经症状的病猪脑组织进行了病原菌分离,对其优势菌进行菌落形态学观察、生化试验、PCR检测、药敏试验和毒株致病力试验.结果显示,成功分离到1株猪链球菌2型,其含有目前已知的mrp、sly、ef3种毒力基因,该菌株对昆明系小鼠、新西兰白兔具有一定的致病性,动物回归试验证实该菌株对断奶仔猪具有较强的致病性.     

鸡传染性支气管炎病毒地方流行株的分离与鉴定

从山西各地区疑似鸡传染性支气管炎(IB)的病料中,分离到5株鸡传染性支气管炎病毒(IBV)分离株,并对分离病毒进行了病毒形态观察、对鸡新城疫病毒(NDV)的干扰、鸡胚致病性试验、动物回归试验、血凝特性试验、病毒理化特性测定等生物特性鉴定及IBV N基因特异性片段的检测.电镜观察,可见直径为60～120 am,有囊膜及纤突呈冠状排列的病毒粒子;对NDV有明显的干扰作用;分离株的传代物均有明显的致鸡胚矮小化作用;动物回归感染死亡鸡肾脏病变明显,表现肾脏肿大、花斑肾现象,输尿管内充塞大量尿酸盐;无直接血凝性,经1%胰酶处理后可凝集鸡红细胞;分离株对乙醚和氯仿敏感;采用反转录-聚合酶链式反应(RT-PCR)对分离毒株进行扩增,结果均扩增出特异N基因核酸片段.     

我国部分地区牛支原体肺炎和关节炎的病原体诊断

重庆等4省市从外省引进的肉牛群发生以严重肺炎和关节炎为主要表现的疾病。该病的病变主要集中于肺脏,其组织学变化主要是间质增生,纤维素渗出,干酪样坏死,淋巴细胞、嗜中性粒细胞和单核细胞浸润。PCR检测病牛肺脏显示牛支原体阳性,而丝状支原体丝状亚种、牛分支杆菌和多杀性巴氏杆菌为阴性。从肺等组织中分离到牛支原体以及大肠杆菌、沙门氏菌、链球菌、葡萄球菌和烟曲霉,没有分离到巴氏杆菌。结果显示本病是以牛支原体感染为主引起的牛支原体肺炎和关节炎,长途运输等应激因素是该病突发的重要诱因,其他细菌和/或真菌继发感染加重了病情。