南京地区奶牛酮病病因和诊断的研究

泌乳早期母牛采食精料不足及精料能量水平偏低所致的能量负平衡是南京地区奶牛酮病的一个主要原因;干乳期精料饲喂过量,可能使产后母牛食欲恢复变慢,而加剧能量负平衡,促进酮病发生;有些产后疾病常影响食欲而导致继发性酮病。诊断学研究表明,乳汁中丙酮加乙酰乙酸含量明显低于血液值,故使用一般酮粉检测乳酮,将会使一些亚临床病例漏检,因此作为其诊断方法并不可靠。     

Towards obtaining long term embryonic stem cell like cultures from a marine flatfish, Scophtalmus maximus

Culturing pluripotent embryonic stem cells represents a unique model system for in vitro studies of embryo cell growth and differentiation, and represents a connection between in vitro and in vivo manipulation of genes. To further develop and refine stem cell technology for marine fish, we have established cultures of embryonic stem cells isolated from turbot blastulas. The pluripotent nature of our turbot-ES-like cells was supported by their morphology and elevated levels of alkaline phosphatase enzyme activity, their ability to remain undifferentiated for a prolonged culture period, their spontaneous differentiation potential in vitro and their ability to form embryoid bodies (EB) in response to changes in the extracellular environment. In addition, we show that turbot ES like cells express Oct-4 required for the maintenance of pluripotency of ES cells. Cells from 100 blastulas (>10⁵ cells/well) were seeded into gelatine coated 24 well cell culture clusters. The cells were polygonal in shape, with dense cytoplasm and large nuclei. The ES-like cells formed colonies within 24 h following seeding, multilayered in a pyramidal fashion, with maximum cell densities in the middle. The cells proliferated vigorously when seeding densities were high and the cells still had not attached to the gelatine-coated surface. Most of the cells became attached to the surface 48 h following seeding. Attached cells grew more slowly and 20% of the plated colonies could be kept stable for 60 days. Eventually, most of the cultures showed extensive differentiation or died. Only a few cultures (4–5%) survived prolonged culturing (>2 months). The cells were stained for alkaline phosphatase activity, a marker of pluripotency and showed intense staining. More specific, turbot ES like cells in culture expressed Oct-4, detected by immunofluorescence staining. Changing the medium conditions by adding retinoic acid and removing LIF, the proportion of embryoid bodies in our cultures increased. ES-like cells as well as fresh, intact fertilised eggs where successfully cryopreserved. ES cells from the cryopreserved eggs could be isolated and seeded into cultures, forming colonies like the cells from freshly fertilised eggs. Also cryopreserved ES-like cells could be successfully plated. The prolonged survival of these cryopreserved cells has not yet been investigated. The establishment of in vitro cultures of turbot ES-like cells represents a new experimental model for marine flatfish. This revised version was published online in July 2006 with corrections to the Cover Date.     

大鲵虹彩病毒的形态结构及其包涵体特征

运用电镜和免疫荧光技术,对纯化的大鲵(Andrias davidianus)虹彩病毒粒子、感染病毒的EPC细胞以及确诊感染病毒的病鲵组织样品进行观察和分析。结果表明,纯化的大鲵虹彩病毒负染后电镜下显示球形结构,具囊膜,直径约150 nm;感染EPC细胞中的病毒颗粒呈典型的正二十面体结构,由核衣壳和核心构成,核衣壳呈正六边形,对角直径为(150±5)nm(N=30),核衣壳厚度约5 nm,核心直径为(98±18)nm(N=27)。在病鲵病变的肺和肾组织中发现存在大量聚集或分散的病毒颗粒,其形态特征和感染EPC细胞超薄切片观察的结果一致。免疫荧光电镜观察结果显示,感染病毒的细胞可观察到明显的红色荧光信号,且呈斑块状分布,大小不等。综合大鲵虹彩病毒初步的形态发生和免疫荧光观察结果,认为病毒感染细胞后在不同的发生时期会形成不同类型的病毒包涵体。     

两种桫椤属植物组培快繁技术研究

以阴生桫椤(Alsophila latebrosa)、大叶黑桫椤(Alsophila gigantea)为研究对象,利用绿色球状体(Green Globular Bodies,GGB)途径,展开快繁体系的研究,以筛选最优的繁殖体系.结果表明:(1)阴生桫椤的快繁体系中,1/10 MS是孢子萌发最优培养配方;1/2 MS...     

Omega-3 Fatty Acids Modulate Weibel-Palade Body Degranulation and Actin Cytoskeleton Rearrangement in PMA-Stimulated Human Umbilical Vein Endothelial Cells

Long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) produce cardiovascular benefits by improving endothelial function. Endothelial cells store von Willebrand factor (vWF) in cytoplasmic Weibel-Palade bodies (WPBs). We examined whether LC n-3 PUFAs regulate WPB degranulation using cultured human umbilical vein endothelial cells (HUVECs). HUVECs were incubated with or without 75 or 120 µM docosahexaenoic acid or eicosapentaenoic acid for 5 days at 37 °C. WPB degranulation was stimulated using phorbol 12-myristate 13-acetate (PMA), and this was assessed by immunocytochemical staining for vWF. Actin reorganization was determined using phalloidin-TRITC staining. We found that PMA stimulated WPB degranulation, and that this was significantly reduced by prior incubation of cells with LC n-3 PUFAs. In these cells, WPBs had rounded rather than rod-shaped morphology and localized to the perinuclear region, suggesting interference with cytoskeletal remodeling that is necessary for complete WPB degranulation. In line with this, actin rearrangement was altered in cells containing perinuclear WPBs, where cells exhibited a thickened actin rim in the absence of prominent cytoplasmic stress fibers. These findings indicate that LC n-3 PUFAs provide some protection against WBP degranulation, and may contribute to an improved understanding of the anti-thrombotic effects previously attributed to LC n-3 PUFAs.     

一例山羊泰勒虫病的临床诊治

 泰勒虫病是一种季节性很强的严重危害牛羊养殖业的蜱传性血液原虫病。介绍一例山羊泰勒虫病的临床症状、病理变化、实验室诊断以及防治方法,为养羊户羊泰勒虫病的预防和防治提供一定参考。     

征地过程中的各方利益主体博弈分析

土地征收引发的社会风险及矛盾日益凸显,给社会的稳定和谐带来一定威胁.通过对中央政府、地方政府及农民之间的博弈分析,明确了征地过程中各方利益主体的行为选择及动机,并得出违规征地的处罚力度及征地补偿费是影响各利益主体行为选择关键的结论.     

叠氮化钠诱变对离体蝴蝶兰类原球茎生理的影响

以2、4、6和8mmol/L的叠氮化钠浸泡6h处理蝴蝶兰类原球茎后进行组织培养,测定了处理组和对照的蝴蝶兰类原球茎中脯氨酸、丙二醛和可溶性糖含量以及超氧化物歧化酶和过氧化氢酶的活力。结果表明,经叠氮化钠处理的类原球茎中的超氧化物歧化酶活力、脯氨酸和丙二醛含量均有上升,而过氧化氢酶活力与可溶性糖含量均有下降,并呈现浓度梯度效应。叠氮化钠诱变的半致死剂量介于4～8mmol/L之间,其中4mmol/L的叠氮化钠对蝴蝶兰类原球茎生理损伤较小,因此认为4mmol/L的叠氮化钠是诱变蝴蝶兰类原球茎较为合理的浓度。     

竹叶兰的无菌播种快繁技术研究

以竹叶兰种子为外植体进行无菌播种，成功诱导原球茎并再生植株，建立其快繁体系。试验结果表明：(1)1/2 MS＋香蕉泥30.0 g/L为最佳种子萌发与原球茎诱导培养基；(2)1/2 MS＋6-BA 1.0 mg/L＋NAA 0.1 mg/L＋香蕉泥30.0 g/L为最佳芽增殖培养基，且芽生长健壮；(3)1/2 MS＋IBA 0.5 mg/L为最适生根培养基。     

蝴蝶兰无性快繁规模化生产中玻璃化原球茎状体产生的原因及其恢复

对蝴蝶兰(Phalaenopsis)组培生产中引起原球茎状体玻璃化的原因以及玻璃化原球茎状体再利用的效果进行了研究。结果表明:随着激素质量浓度增高和继代培养时间的延长,原球茎状体玻璃化程度加重。当激素NAA为5mg/L、BA为10mg/L,继代培养到第9代时,2种培养基中玻璃化率分别高达71%和65%。玻璃化原球茎状体的平均增殖率仅为2.2%,再生植物率为183株/瓶,明显低于正常的原球茎状体的5.3%和1297株/瓶。玻璃化原球茎状体在无激素培养基中经2～3代培养后,玻璃化原球茎状体的数量下降到0.84%,玻璃化现象可得到明显恢复,恢复后的原球茎状体的分化能力和植株生长状态与正常原球茎状体一致,无变异现象发生,可继续应用于组培生产。