大白菜抗软腐病基因BrWRKY33植物表达载体的构建

利用农杆菌侵染法获得抗软腐病转BrWRKY33基因大白菜,首先要构建植物表达载体。本实验根据BrWRKY33基因的序列及pROK2表达载体的酶切位点设计引物(FN/RN),获得BrWRKY33基因,然后将该基因连接到克隆载体pGEM-TEasy,重新构建了克隆载体T-WRKY。经测序及酶切验证,选取PCR反应中错配率最低的产物,构建了表达载体pROK2-WRKY,并将该表达载体转入到根癌农杆菌EHA105中,并对其转化子进行了鉴定。结果表明,PCR扩增获得目的基因BrWRKY33全长约1443bp,PCR及酶切结果鉴定表明克隆载体T-WRKY已经重新构建成功。表达载体的PCR及BamHⅠ和KpnⅠ双酶切鉴定表明有4个重组子表现阳性,表明目的基因已经插入到pROK2表达载体,表达载体构建成功。PCR鉴定表明表达载体pROK2-WRKY已经转入根癌农杆菌EHA105中。本实验结果将为进一步研究大白菜抗软腐病基因的转化奠定基础。     

Immunohistochemical and ultrastructural identification of Fusobacterium necrophorum subsp. necrophorum in bovine fatal necrotizing glossitis

A 37-day-old male Japanese black calf showing marked salivation and leucocytosis died and was examined the tissues histologically. Histological lesions were characterized by severe focal necrotic glossitis on the ventral side of the root of the tongue. Immunohistochemically, Fusobacterium necrophorum subsp. necrophorum antigen was detected in the necrotic tissues and its distribution corresponded to that of the gram-negative, nonsporeforming, long filamentous organisms. Ultrastructural similarities between the organism and F. necrophorum subsp. necrophorum, but not subsp. funduliforme were observed. These findings clearly demonstrated that the fatal necrotic glossitis was caused by F. necrophorum subsp. necrophorum. This is the first report of bovine fatal necrotizing glossitis with leucocytosis caused by F. necrophorum subsp. necrophorum infection, and this organism may be an important fatal pathogen in calves with glossal lesions.     

Molecular characterizations of avian polyomavirus isolated from budgerigar in China

Budgerigar fledgling disease is an acute viral infectious disease caused by avian polyomavirus (APV). In this study, 34 liver tissue samples of young, dead budgerigar with typical symptoms were collected in 2004. All the samples had positive polymerase chain reaction (PCR) test based on the VP1 specific primers. VP1 genes of these samples were sequenced and had high similarities to each other (99%-100%). A strain (HBYM02) was isolated and sequenced. As shown in the phylogenetic tree, there are two branches. One branch was composed by strains isolated from Passeriformes, and the other was composed only by one strain isolated from Falconiformes. The genome similarities between our isolate and other reported isolates were very high (> 99%), and the evolution distances in the phylogenetic tree were very short (< 0.005), which suggests that APV in China has the same genotype as those in other regions. The results will be useful for the diagnoses of, and vaccine development for, APV.     

关于防护林的防护成熟概念

该文在前人研究的基础上 ,针对防护成熟概念中所存在的不足 ,提出从防护林经理原则和防护效益变化过程两方面来进行研究 ,认为防护林经理应遵循可持续、经济和防护功能为主导的原则 ,由防护林防护作用发挥过程得到防护林生长过程的 4个阶段 ,建立了防护林防护成熟和防护成熟龄概念     

华北落叶松抗坏血酸氧化酶年变化规律初探

该文对华北落叶松 (Larixprincipis rupprechtiiMagr)成年林木及苗木不同器官、不同时期的抗坏血酸氧化酶活性变化情况进行了初步探讨 .结果表明 :≤ 2mm根中抗坏血酸氧化酶活力最高 ;体内抗坏血酸氧化酶活力在生长季节较高 ;林木梢头、叶、1年生枝及苗叶等生长部位抗坏血酸氧化酶活力也较高 .抗坏因酸氧化酶与华北落叶松的生长关系较为密切 ,而与其抗逆性无关     

非洲猪瘟疫苗和病原学诊断技术研究进展

非洲猪瘟疫情给我国养猪业造成了巨大经济损失，因而开发安全高效的疫苗和建立快速可靠的病原学诊断方法对该病防控具有重要意义。本文综述了当前国内外非洲猪瘟（African swine fever，ASF）疫苗和病原学诊断技术的研究进展，以期为今后ASF疫苗研制和诊断技术选择提供参考。疫苗研究方面，目前仍无安全有效疫苗上市。灭活疫苗不能提供有效的免疫保护力，已不作为今后研究的重点方向；减毒活疫苗存在生物安全隐患，疫苗接种后的安全性、有效性等有待进一步评估；基因工程疫苗与前两种疫苗相比，成本低且安全性高，但对强毒株攻击的有效保护作用不强。目前认为利用天然分离或敲除非洲猪瘟病毒（African swine fever virus，ASFV）毒力基因的致弱毒株开发重组减毒活疫苗具有较好的利用前景，但其安全性和有效性仍有待进一步研究。目前在没有有效疫苗免疫的前提下，建立快速、可靠的早期病原诊断方法对于ASF疫情确认和控制同样至关重要。近年来，ddPCR、LAMP、RPA、CRISPR/Cas等新兴诊断技术相继涌现。这些方法具有操作更简单、检测速度更快、特异性更强等方面的优势，但其检测能力与适用场景尚存在一定不足，还需要进一步完善。未来ASFV病原学检测的研究方向应建立在成本低廉、简单便捷、高效准确、集成化的基础上，或可将多种诊断方法联合应用，各取所长。     

3种核桃青皮提取物对玉米螟中肠酯酶活性的影响

通过核桃青皮馏分3、6与核桃青皮萃取物青甲水对玉米螟幼虫进行了室内毒力测定,以及中肠酯酶离体活性测定,结果表明核桃青皮馏分6对玉米螟5龄幼虫有较强地抑制作用,青甲水对中肠酯酶的抑制作用不显著。     

Adaptive immune response of Vgamma2Vdelta2+ T cells during mycobacterial infections

To examine the role of T cell receptor (TCR) in gammadelta T cells in adaptive immunity, a macaque model was used to follow Vgamma2Vdelta2+ T cell responses to mycobacterial infections. These phosphoantigen-specific gammadelta T cells displayed major expansion during Mycobacterium bovis Bacille Calmette-Guérin (BCG) infection and a clear memory-type response after BCG reinfection. Primary and recall expansions of Vgamma2Vdelta2+ T cells were also seen during Mycobacterium tuberculosis infection of naive and BCG-vaccinated macaques, respectively. This capacity to rapidly expand coincided with a clearance of BCG bacteremia and immunity to fatal tuberculosis in BCG-vaccinated macaques. Thus, Vgamma2Vdelta2+ T cells may contribute to adaptive immunity to mycobacterial infections.