细菌的病毒——噬菌体最新分类与命名

2005年，国际病毒分类委员会（International Committeeon Taxonomy of viruses，ICTV）发表了《病毒分类一国际病毒分类委员会第8次报告》（以下简称第8次报告）对目前已经确认并比较系统研究的绝大多数细菌的病毒——噬菌体（Bacterial viruses，或bacteriophages），根据病毒核酸类型、形态结构、基本特性以及宿主菌类型等特征，进行了系统的依据分类与命名。     

最新家蚕病毒命名和分类

据《Archives Virology》杂志2012年4月6日上线发表的“Ratification vote on taxonomic proposals to the International Committee on Taxonomy of Viruses （2012） ”文章报道。     

最新脊椎动物病毒分类简介

最新脊椎动物病毒分类简介陆承平（南京农业大学动物医学院，南京２１００９５）国际病毒分类委员会（ＩＣＴＶ）编写的第６次病毒分类报告（下称第６次报告）最近问世。虽然第６次报告与第５次病毒分类报告发表时间相隔不过３年，但其内容和形式均有重大变化［１］。第６...     

挤奶机分类及命名方法的探讨

根据挤奶机结构特点和功能,结合目前已经成熟的命名方法,形成一套能反映挤奶机特征的命名方法,这对规范行业,促进市场成熟,便于用户比较购机和提高产品质量监督管理效率具有重要意义。     

A群轮状病毒的分类及命名

1分类轮状病毒（RV）属于呼肠孤病毒科（Reoviridae）、轮状病毒属（Rotavirus）。完整病毒粒子为无囊膜,球状,呈20面体结构,直径小于100纳米,由外层衣壳,内层衣壳和核心衣壳3层蛋白衣壳组成。轮状病毒基因组由11节段双股RNA组成,     

抗猪流感噬菌体单链抗体库的构建与筛选

利用噬菌体展示技术构建猪流感病毒噬菌体抗体库,并筛选出猪流感高特异性、高亲和力的单链抗体(scFv)。以猪流感病毒免疫BALB/c小鼠,提取脾细胞总RNA,反转录后以cDNA为模板扩增获得VH基因和VL基因,并采用重叠延伸PCR(SOE-PCR),用柔性多肽Linker接头(Gly4Ser)按VH-Linker-VL方式将VH基因和VL基因拼接成scFv基因片段。将scFv基因和pCANTAB5E载体分别双酶切(SfiⅠ/NotⅠ)后连接,转化宿主菌TG1,经过辅助噬菌体M13K07拯救,构建噬菌体单链抗体库。以猪流感病毒为抗原包被96孔酶标板,经过3轮的亲和富集筛选,用Phage-ELISA鉴定阳性重组抗体。本研究成功构建出库容约为4×106cfu/mL抗猪流感病毒的单链抗体库,并筛选出4株特异性抗猪流感病毒的scFv抗体,能够与鼠源阳性多抗进行竞争结合猪流感病毒,为抗猪流感病毒转基因猪的研究奠定基础。     

噬菌体展示技术原理及其在生物学研究中的应用

噬菌体展示技术是一种用于筛选和改造功能性多肽的技术,通过将编码多肽的基因片段与编码噬菌体表面蛋白的基因融合进而以融合蛋白形式表达于噬菌体表面.该技术被广泛用于研究蛋白质的结构与功能、蛋白质间的识别与相互作用、抗原表位筛选及疫苗的研制等,并产生了深远的影响.文章简要介绍了噬菌体展示技术原理、随机肽库生物淘洗过程及该技术在病毒学和新型疫苗研究中的应用.     

丝状噬菌体与噬菌体展示技术在抗体库中的应用

丝状噬菌体展示技术是将外源蛋白通过与丝状噬菌体外壳蛋白融合而表达于噬菌体颗粒的表面。自问世以来,它已被应用于生物科学的许多领域,其中最具吸引力的是抗体工程,利用该技术可构建不同的抗体库,从而获得针对不同抗原的抗体。本文着重介绍了丝状噬菌体的生物学特征...     

噬菌体肽库技术筛选抗PRRSV肽及其应用

噬菌体展示肽库是一种被广泛用于抗原表位鉴定,结合蛋白筛选的技术。该试验利用噬菌体展示技术筛选与猪呼吸与繁殖障碍综合征病毒（PRRSV）ORF1B复制酶蛋白相互作用的蛋白,并进一步验证筛选蛋白的抗病毒作用。以表达纯化的PRRSV ORF1B蛋白CTD包被高亲和性96孔板作为靶蛋白,应用T7噬菌体展示技术对随机12肽库cDNA文库进行筛选,并分析测序筛选的克隆。将筛选出的克隆序列合成后,在体外验证合成多肽的抗PRRSV效果。结果表明,在4轮的噬菌体筛选后,共得到87个阳性克隆,经测序鉴定出11个筛选的12肽,并通过体外抗病毒试验得到P10是一个具有高抗病毒活性的12肽。试验结果为PRRSV的抗病毒研究奠定了基础。     

An introduction to biosecurity of cattle operations.

Recent world events have heightened awareness for the need to safeguard our livestock industries from disease agents. Biosecurity is the outcome of all activities undertaken to preclude introduction of disease agents into an animal population. The concepts of biosecurity are not new. Activities directed at ensuring biosecurity include controlling exposure and optimizing resistance. Programs for biosecurity must be individually tailored to specific situations to account for varying risks and perceptions of risk by decision makers. It is important for practitioners to take a holistic approach to disease control, considering the epidemiology of the disease in addition to the available vaccines and therapeutics.     

Bovine mycoplasmas: classification of groups related to Mycoplasma mycoides.

Mycoplasmas which had in various ways proved to be related to Mycoplasma mycoides were studied with a view to classification and nomenclature. Representative strains of M. mycoides — subspecies mycoides (PG1) and subspecies capri (PG3) — and of the as yet unclassified bovine serogroups 7 (PG50) and L (B144P) were compared serologically and by DNA-DNA hybridization. The serological methods used (metabolism inhibition, growth inhibition and immunofluorescence) are usually considered to be species-specific.

1. The two subspecies of M. mycoides can be clearly separated by all three serological methods, whereas the hybridization studies revealed great similarity between them, the relatedness value being 0.70.
2. The two serogroups (7 and L) cross-reacted with each other in all three serological tests, and their relatedness value was 0.83. The relatedness value between group 7 and M. mycoides subsp. mycoides was found to be 0.72, and only limited cross-reactions were demonstrated by immunofluorescence and growth inhibition.
3. Although groups 7 and L were found only to a slight degree to be genetically related to M. bovigenitalium with a DNA homology of 20 % or less, a serological cross-reaction between group 7 and M. bovigenitalium has been demonstrated by growth inhibition in previous studies.

Conclusions drawn on the basis of the premises just mentioned give rise to a dilemma, because three different situations exist. In (1), significant serological differences were disclosed, but the DNA homology was great. In (2), the serogroups 7 and L showed conformity between hybridization and serological findings, whereas, in (3), hybridization showed a distinct separation, but a serological cross-reaction does occur. If the results of hybridization are regarded as decisive, the two subspecies of M. mycoides can be preserved, but this is at variance with the general perception that the serological methods used here are species-specific. If, on the other hand, the serological results are chosen to be decisive, PG1 and PG3 must be regarded as two separate species, and consequently Group L/7 may also be a separate species.As regards the relation between group L/7 and M. bovigenitalium, the results of hybridization clearly show that they are two different species. As a consequence of this, it must be accepted that cross-reactions may occur — also in growth inhibition — between different species which, genetically, are even far removed from each other.On account of the fundamental nature of these problems, the authors prefer to leave the decisions — also as to the nomenclature — to the Subcommittee on the Taxonomy of Mycoplasmatales.     

草业琐谈之十九--草业科学源头浅说

想谈谈草业科学源头的故事.这不仅有趣,也有利于了解草业科学航程的时空坐标,还将有助于对草业科学的全面了解并判断它的发展趋向. 自从有了人类的渔猎活动,草业生产的素材就开始积累.这些素材,在不同的历史时期,不同的生态区域,不断累积和发展,逐渐形成了自己的生产特征,也就连带出现了相应的科学内涵.     

No evidence for adaptation of current egg drop syndrome 1976 viruses to chickens

In order to determine whether the current field strains of egg drop syndrome (EDS) 1976 viruses adapt to chickens, we compared the growth efficiency of three Japanese field strains (PA-1/79, AWI/98, Gifu/01) in chicken and duck embryo liver cells. The growth efficiency in chicken or duck embryo liver cells was almost similar in these strains. The fiber protein may carry the type-specific antigen and the hemagglutination activity, and hexon protein may contain the subgroup-specific antigenic determinants. Therefore, the fiber head and hexon loop 1 DNA domain sequences of the six Japanese field strains UPA-1/79, ME/80, 44/81, Kyoto/91, AWI/98, Gifu/01) were compared, but these DNA domains were identical among the six field strains. Our data suggested that the EDS virus was maintained without discernible changes for the last two decades in the field.     

Nasca classification of hemivertebra in five dogs

: Five dogs, four small mixed breed and a Doberman Pinscher, presented in our clinic with hemivertebra. Complete physical, radiological and neurological examinations were done and the spinal deformities were characterized in accord with the Nasca classification used in human medicine. Two dogs had multiple hemivertebrae (round, oval or wedge-shaped: Type 3) in the thoracic region; one dog had an individual surplus half vertebral body (Type 1) plus a wedge-shaped hemivertebra (Type 2b) in the lumbar region; one dog had multiple hemivertebrae which were fused on one side (Type 4a) in the thoracic region; and one dog had a wedge-shaped hemivertebra (Type 2a) in the cervical region.     

An introduction to principles of veterinary clinical pharmacology: General principles

Three hundred and sixty goats, pregnant from an estimated 72 days to almost full-term, aborted between 30 and 50 hours afterreceiving 0.25 or 0.5ml cloprostenol by subcutaneous or intramuscular injection. Despite close observation, no goat was seen aborting. All membranes and some foetal limbs were consumed, afterwhich the foetuses (and three live kids) were abandoned.

Fourteen goats died from blood poisoning due to CI. chauvoei between 30 and 40 hours after aborting. It is recommended that an immunisation programme precede the induction of abortion or premature parturition in the goat.