Plant type differently promote the arbuscular mycorrhizal fungi biodiversity in the rhizosphere after revegetation of a degraded, semiarid land

It is suggested that the diversity of arbuscular mycorrhizal fungi (AMF) and their association with distinct plants species are crucial in the early stages of revegetation procedures since the AMF roots colonisation plays an important role improving plant establishment and growth. We carried out a study where we analyse the AMF community composition in the roots of Ephedra fragilis, Rhamnus lycioides, Pistacia lentiscus and Retama sphaerocarpa fourteen months after revegetation in a Mediterranean semiarid degraded area of southeast Spain in order to verify whether different plant species can variably promote the diversity of AM fungi in their rhizospheres after planted. We analysed a portion of approximately 795 bases pairs of the small-subunit ribosomal DNA by means of nested PCR, cloning, sequencing and phylogenetic analyses. Eight fungal sequence types belonging to Glomus group A and B and to the genus Paraglomus were identified. The different plant species had different AM fungal community composition. Thus, R. lycioides harboured the highest number of four fungal sequence types while from E. fragilis only two types could be characterized that were specific for this plant species. P. lentiscus and R. sphaerocarpa harboured each one three sequence types and two of them were shared. All AMF sequence types were found in the natural soil. These results show that one effective way of restoring degraded lands is to increase the number of plant species used, which would increase the AMF diversity in the soil and thus the below-ground, positive interactions.     

Generation of transgenic corn-derived Actinobacillus pleuropneumoniae ApxIIA fused with the cholera toxin B subunit as a vaccine candidate

Corn, one of the most important forage crops worldwide, has proven to be a useful expression vehicle due to the availability of established transformation procedures for this well-studied plant. The exotoxin Apx, a major virulence factor, is recognized as a common antigen of Actinobacillus (A.) pleuropneumoniae, the causative agent of porcine pleuropneumonia. In this study, a cholera toxin B (CTB)-ApxIIA#5 fusion protein and full-size ApxIIA expressed in corn seed, as a subunit vaccine candidate, were observed to induce Apx-specific immune responses in mice. These results suggest that transgenic corn-derived ApxIIA and CTB-ApxIIA#5 proteins are potential vaccine candidates against A. pleuropneumoniae infection.     

Protection of chickens from Newcastle disease with a recombinant baculovirus subunit vaccine expressing the fusion and hemagglutinin-neuraminidase proteins

Recombinant baculoviruses containing the fusion (F) and hemagglutinin-neuraminidase (HN) glycoprotein gene of the viscerotropic velogenic (vv) Newcastle disease virus (NDV) isolate, Kr-005/00, and a lentogenic La Sota strain of the NDV were constructed in an attempt to develop an effective subunit vaccine to the recent epizootic vvNDV. The level of protection was determined by evaluating the clinical signs, mortality, and virus shedding from the oropharynx and cloaca of chickens after a challenge with vvNDV Kr-005/00. The recombinant ND F (rND F) and recombinant HN (rND HN) glycoproteins derived from the velogenic strain provided good protection against the clinical signs and mortality, showing a 0.00 PI value and 100% protection after a booster immunization. On the other hand, the combined rND F + HN glycoprotein derived from the velogenic strain induced complete protection (0.00 PI value and 100% protection) and significantly reduced the amount of virus shedding even after a single immunization. The rND F and rND HN glycoproteins derived from the velogenic strain had a slightly, but not significantly, greater protective effect than the lentogenic strain. These results suggest that the combined rND F + HN glycoprotein derived from vvNDV can be an ideal subunit marker vaccine candidate in chickens in a future ND eradication program.     

鸡新城疫病毒HN基因亚单位疫苗诱导免疫保护的实验研究

实验分别将应用Bac to Bac系统表达的新城疫病毒四平株和长春株血凝素-神经氨酸酶基因（HN基因）蛋白的重组杆状病毒感染Sf-9昆虫细胞后28℃培养72h后，洗涤、收集昆虫细胞，离心浓缩，-20℃冻融3次，用HA-HI实验和HN单抗中和试验测定表达产物的活性，将表达的重组蛋白作为亚单位疫苗免疫鸡，用间接ELISA和HI试验测定鸡体内抗体效价，免疫后第15d用国家标准强毒NDVF48E8攻毒，统计免疫保护率，结果表明，表达的NDVHN重组蛋白能够诱导鸡体产生抗NDV特异性IgG抗体和HI抗体，实验Ⅰ组（四平株）雏鸡保护率为65%，实验Ⅱ组（长春株）雏鸡保护率为100%。     

温度对黑龙江大豆主栽品种球蛋白的影响

利用SDS-PAGE方法分析6个温度梯度对黑龙江6个主栽大豆品种的7S和11S球蛋白含量的影响.结果表明:7S和11S球蛋白呈显著正相关的关系.7S和11S球蛋白含量在品种间和地点间差异均极显著.品种和温度互作7S和11S球蛋白含量均不显著.6个品种中绥农10、黑农35、东农42和东农46营养价值较高,为今后优质品质资源的筛选和优质新品种的选育提供了参考价值.     

禽大肠杆菌菌毛产生的特性及免疫原性研究

用电镜检查广西分离的鸡致病性大肠杆菌 O_(60),O_(7)和 O_(8)菌株,在37℃和43℃培养均可见到菌毛,低于28℃不产生菌毛。用营养肉汤,Minca 培养液或最低限量培养液培养,冰浴高速磁力搅拌和MgCl_2反复沉淀提取,可得到较纯的菌毛。经测定,O_(60),O_(7)和 O_(8)菌毛蛋白分子量分别是15500,17500和17800。1日龄雏鸡用 O_(60)菌毛亚单位油乳苗皮下注射和菌毛悬浮液气雾免疫,均可保护鸡免受大肠杆菌对气囊的攻击。O_(60),O_(7)和 O_(8)菌株菌毛之间缺乏显著的交互保护。雏鸡在1日龄和10日龄用 O_(60),O_(7)和 O_(8)多价菌毛油乳苗免疫,21日攻毒时,可抵抗3种菌株侵袭气囊造成的急性呼吸道感染。     

口蹄疫病毒受体羊源整联蛋白β6亚基配体结合域的原核表达、纯化及鉴定

利用原核细胞表达羊口蹄疫病毒(FMDV)受体整联蛋白β6亚基的配体结合域 (LBD)片段,分离纯化目的蛋白.以含有羊整联蛋白β6亚基全长cDNA的质粒为模板,PCR扩增得到β6LBD基因片段,经酶切消化处理后与同样酶切处理的原核表达载体pP_(RO)EX~(TM)HTb相连,构建原核表达质粒pP_(RO)/β6LBD,测序确认读码框正确后,将其转化感受态细胞 BL21 (DE3),IPTG诱导表达重组羊β6LBD融合蛋白.SDS-PAGE鉴定重组蛋白的表达并利用镍离子亲和树脂对其纯化,通过酶联免疫吸附试验(ELISA)和Western blot方法分析鉴定表达产物.成功构建了pPRO/β6LBD原核表达载体,实现了羊FMDV受体整联蛋白亚基β6LBD在大肠杆菌中的高效表达, SDS-PAGE显示其相对分子质量(Mr)约为33 kDa,重组蛋白主要以包涵体形式存在于菌体中.用本试验室保存的抗FMDV受体猪源整联蛋白β6亚基LBD的单克隆抗体进行ELISA 和Western blot检测,显示该单抗可与重组目的蛋白发生特异性反应,证明纯化后的蛋白与特异性抗体具有良好的特异性反应及抗原活性.为深入研究整联蛋白受体β6亚基在羊体内的分布及其在FMDV致病过程中的作用机制奠定了基础.     

微波对雏鸡的认知功能和NMDA受体亚基基因表达的影响

[目的]研究微波对鸡胚生长发育及雏鸡认知功能的影响。[方法j采用磁控管发射2450MHz的微波来模拟微波辐射源辐射种蛋，直到雏鸡孵出后，分别采用一次性被动回避学习和RT—PCR检测微波对雏鸡认知功能和NMDA受体NRl亚基与NR2亚基表达量的影响。f结果]微波辐射后，暴露组的回避率显著低于对照组，特别在辐射强度最高组的回避率极显著低于对照组。同时暴露组有2组雏鸡体重增加，其中一组的孵化时间有所增加。经RT—PCR分析，NR2亚基表达量在第lO天及15天时都上调，NRl亚基表达量只在第15天时才下调。[结论]微波对个体发育具有一定影响，通过使端脑中NMDA受体结构组成和功能发生改变，使自身的调节能力下降，从而对认知功能有一定损害。     

鱼用基因工程疫苗研究进展

疫苗是目前控制鱼类病害最经济有效的方式。免疫学及生物工程的迅速发展极大地促进了鱼类基因工程疫苗的研究。基因工程疫苗克服了传统疫苗的一些缺陷和不足，显示出巨大的应用前景，已成为国内外水产养殖业的研究热点，近年对鱼用基因工程疫苗的研究已取得较大进展，但鱼用基因工程疫苗在研究和应用过程中也面临着急需解决的若干问题。