三种不同灭活方法对新城疫病毒血凝和RT-PCR试验结果的影响

为研究热灭活、甲醛、β-丙内酯(BPL)三种不同灭活方法对新城疫病毒(NDV)血凝和RT-PCR试验结果的影响,将收获的NDV鸡胚尿囊液分别用浓度为0.1%~0.5%的甲醛37℃灭活24 h或4℃灭活48 h、浓度为0.02%~0.2%的BPL 37℃灭活9 h、60℃热灭活30~90 min,并于灭活前后进行血凝试验和RT-PCR检测。结果表明,用0.02%的BPL 37℃灭活9 h或0.1%的甲醛4℃灭活48 h,不影响NDV的血凝价;采用热灭活30 min或0.02%的BPL 37℃灭活9 h,不影响NDV核酸检测。本研究可为相关病原检测以及诊断制品制备过程中灭活方法的选择提供参考。     

紫外线辐射灭活斑马鱼精子及其激活卵子发育的初步研究

精子的灭活是雌核发育过程中的一个关键步骤,为了研究不同介质中斑马鱼精子的灭活效果,将斑马鱼的精子分别置于纯水（A）、Cortland鱼用生理盐水（B）、M199培养基（C）、Hank’s液（D）以及Ringer氏溶液（E）中进行紫外线照射,然后与正常卵子进行人工受精,统计受精率、孵化率以及畸形率。结果显示,各种介质中均得到畸形鱼苗,并有明显的单倍体综合症现象;五种介质中在Cortland鱼用生理盐水中平均受精率最高;综合受精率和畸形苗的比例,35s辐射比较适于斑马鱼精子灭活与激活卵的发育。畸形鱼苗的染色体检测结果显示,其染色体众数为25,为斑马鱼染色体数目的一半,少数分裂相的数目介于25和50之间。     

Depressed growth of non‐chlorotic vine grown in calcareous soil is an iron deficiency symptom prior to leaf chlorosis

The development of iron deficiency symptoms (growth depression and yellowing of the youngest leaves) and the distribution of iron between roots and leaves were investigated in different vine cultivars (Silvaner, Riparia 1G and SO4) grown in calcareous soils. As a control treatment all cultivars were also grown in an acidic soil. Only the cultivars Silvaner and Riparia 1G showed yellowing of the youngest leaves under calcareous soil conditions at the end of the cultivation period. All cultivars including SO4 showed severe shoot growth depression, by 50 % and higher, before yellowing started or without leaf yellowing in the cultivar SO4. Depression of shoot growth occurred independently from that of root growth. In a further treatment the effect of Fe‐EDDHA spraying onto the shoot growth of the cultivar Silvaner after cultivation in calcareous soil was investigated. Prior to Fe application plants were non‐chlorotic, but showed pronounced shoot growth depression. Spraying led to a significant increase in shoot length, though leaf growth was not increased. Accordingly, depression of shoot growth of non‐chlorotic plants under calcareous soil conditions and with ample supply of nutrients and water has been evidenced to be at least partly an iron deficiency symptom. We suggest that plant growth only partially recovered because of dramatic apoplastic leaf Fe inactivation and/ or a high apoplastic pH which may directly impair growth. Since growth was impaired before the youngest leaves showed chlorosis we assume that meristematic growth is more sensitively affected by Fe deficiency than is chlorophyll synthesis and chloroplast development. In spite of high Fe concentrations in roots and leaves of the vines grown in calcareous soils plants suffered from Fe deficiency. The finding of high Fe concentrations also in young, but growth retarded green leaves is a further indication that iron deficiency chlorosis in calcareous soils is caused by primary leaf Fe inactivation. However, in future, only a rigorous study of the dynamic changes of iron and chlorophyll concentration, leaf growth and apoplastic pH at the cellular level during leaf development and yellowing will provide causal insights between leaf iron inactivation, growth depression, and leaf chlorosis.<?show $6#>     

化学因素对马铃薯病毒钝化的研究

通过出苗与田间试验检测,对１０种化学试剂在不同途径的使用,及对病毒的敏感性两方面,研究了化学因素对马铃薯病毒钝化的作用。结果表明,不同梯度的高锰酸钾、过氧化氢、新洁尔灭、尿素稀释液浸种,病毒钝化明显,发芽正常,出苗齐全,病毒再感染种类少,产量明显提高,且成本低,无公害,操作便捷,宜推广。     

植物源抗病毒制剂 VA 对烟草花叶病毒(TMV)体外钝化作用的初步研究

用植物源抗病毒制剂VA与烟草花叶病毒 (TMV)混合 ,经枯斑半叶法接种 ,结果证明 ,VA对TMV有较强的体外钝化作用 ,体外钝化后的枯斑抑制率为 80 .0 % ;用苯酚氯仿法提取TMV的核酸后 ,按一定的比例与VA混合 ,经枯斑半叶法接种测得枯斑抑制率为 43.8%～ 77.9% ;TMV与VA混合后用RNase处理 ,测得侵染率为 78.6 % ,比未用RNase处理的对照降低了 2 1.4% ,由此说明VA具有一定的体外脱衣壳作用 ;又经电镜观察发现VA可使部分TMV粒体发生断裂或粗细不均、略变弯曲等畸变现象。     

几种植物提取液对TMV体外活性及烟草叶片超微结构的影响

[目的]烟草普通花叶病毒病(TMV)是对烟叶产量和质量影响严重的一种病害.本研究为利用环保型植物源制剂防治烟草花叶病毒病提供理论依据.[方法]分别用水煎煮和乙醇浸提2种方法提取白花蛇舌草、莲叶和配伍多种植物的提取液.取等体积的植物提取液与烟草花叶病毒混合,观察TMV粒体形态及体外钝化效果,将提取液喷施感染TMV的烟叶上,观察烟草叶片超微结构的变化,并进行大田试验.[结果]正常的TMV粒体呈刚直、杆状,植物提取液与TMV等体积混合后,由于提取液的种类和作用时间不同,TMV粒子有不同程度的破坏、断裂或凝聚,感染TMV叶片细胞中存在大量杆状病毒粒子及其垛叠成的结晶体,叶绿体肿胀,外膜破裂,基粒片层紊乱、解体,细胞器消失,细胞空泡化.经植物提取液处理后,上述症状明显减轻.植物提取液对TMV的体外钝化效果分别为:白花蛇舌草50.77%-60.61%、莲叶73.39%-85.19%、制剂91.30%-92.13%,制剂比其它2种效果明显,大田试验验证制剂防治效果达71.02%-81.92%.[结论]植物提取液对TMV粒体有明显的破坏作用,因而能减轻TMV对烟草的危害.     

二氧化氯（ClO2）在桑叶消毒上的应用研究

为探讨二氧化氯（ClO2）对桑叶质量、家蚕微孢子虫和肠球菌的灭活作用及其稳定性、腐蚀性,以直接喷洒桑园桑叶和浸泡离体桑叶消毒的方式,测定ClO2对桑叶质量的影响,并用悬液法和桑叶片载体法处理家蚕微孢子虫,测定ClO2对微孢子虫的灭活效果。结果显示,浓度在500 mg/L以下的ClO2溶液对桑叶质量无显著影响;采用悬液法时,30 mg/L ClO2溶液处理6.0 min即可达到完全杀灭家蚕微孢子虫的效果,而漂白粉精浓度需要达到0.24%才具有同等效果;采用桑叶片载体法时,300 mg/L ClO2溶液处理10.0 min可达到完全杀灭家蚕微孢子虫的效果。以10 mg/L ClO2溶液处理1.0 min,可完全杀灭家蚕肠球菌。ClO2稳定性较差,对金属具有中度腐蚀性。可见,ClO2适合作为桑叶消毒剂用于预防家蚕微粒子病的发生。     

Aspects of bacterial resistance to antimicrobials used in veterinary dermatological practice

Aspects of bacterial resistance to the major classes of antimicrobials used in veterinary dermatology are presented in this review. Resistance of gram-positive and gram-negative bacteria to tetracyclines, macrolide-lincosamide-streptogramin antibiotics, chloramphenicol, mupirocin, sulphonamides, trimethoprim, aminoglycosides, fluoroquinolones and β-lactam antibiotics are depicted with respect to the different mechanisms of acquired and intrinsic resistance. Examples are given for the three major resistance mechanisms, enzymatic inactivation, decreased intracellular drug accumulation and target modification. In addition, basic information about mobile genetic elements which carry resistance genes, such as plasmids, transposons and gene cassettes, and their modes of spreading via transduction, conjugation, mobilization and transformation is provided.     

Activity Of Bacterial Proteolytic Enzymes on Antinutritional Factors in Soybeans and the Effect on Growth and Organ Weights of Piglets

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Inactivation of Antinutritive Factors in Soya Bean by Proteolytic Enzymes

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