猪链球菌2型四川株与江苏株对SPF猪的致病性

以SPF巴马小型猪为实验动物,分别用猪链球菌2型四川分离株以及江苏分离株进行攻击,通过临床症状观察、病理解剖检查、病原分离鉴定以及病原组织分布检测等,比较二者的致病性。结果表明:四川株攻击猪40 h后出现神经症状,关节肿大和全身出血等不很明显;病程为6￣7 d,而江苏株攻毒后18 h即出现神经症状,20 h即有死亡者,关节肿大和全身出血明显。死后病理解剖观察可见,四川株猪主要表现为肺淤血、肿大以及脑水肿,而未见败血症的变化,全身性出血不明显;而江苏株猪除了肺淤血、肿大以及脑水肿外,出现明显的败血症变化。均分离到与攻击相同的细菌,细菌溶血特性不明显,革兰氏阳性染色典型。细菌在组织中分布不同菌株也有一定的差异。     

SPF胶合木植筋抗拔性能研究

采用“拉-拉”荷载模式研究SPF(云杉-松木-冷杉)胶合木植筋抗拔性能,探讨了边距、胶层厚度以及长径比等对胶合木植筋连接抗拔强度和破坏模式的影响.结果表明:边距对植筋连接抗拔强度有显著影响,胶层厚度对植筋抗拔强度有极显著影响,长径比是影响植筋连接抗拔强度的重要因子;植筋连接抗拔强度随长径比的增大而增大,当长径比达到一定值时植筋抗拔强度取决于植筋杆的屈服强度;胶合木开裂、植筋杆拔出和植筋杆屈服是试验中的3种主要破坏模式.     

Reduced mucosal injury of SPF chickens by mast cell stabilization after infection with very virulent infectious bursal disease virus

Recent studies here have demonstrated that increased mast cell populations and tryptase activity contribute to lesion formation in regions of immune organs in special-pathogen-free chickens after infection with very virulent infectious bursal disease virus (vvIBDV). Mast cells and their mediators have been implicated in acute inflammatory injury after vvIBDV infection, but their precise role in this process remains elusive. In this study, the role of mast cells in the vvIBDV infection process was examined using ketotifen, a mast cell membrane stabilizer. On days 1, 2, and 3 postinfection, the bursa of Fabricius (BFs) were collected to quantify mast cells, tryptase and histamine contents by cytochemistry, immunohistochemistry and fluorospectrophotometry analyses, respectively. The results showed that the mast cell populations, tryptase expression, and histamine released increased significantly in the BFs (p < 0.01) of infected birds compared to controls, and acute inflammatory responses were observed in the former. In contrast, in infected chickens pretreated with ketotifen, mast cells, tryptase, and histamine were markedly decreased (p < 0.01) and probably as a result, the BFs remitted significantly. The overall results suggest that mast cells are positively involved in BF injury induced by vvIBDV infection. Inhibition of mast cell degranulation and concurrent mediator release may represent a novel strategy to modulate this process. This study, thus, advances the understanding of the acute inflammatory injury mechanisms triggered by vvIBDV infection and the contribution of mast cell activity in this process.     

植物喷施灵对新疆杨扦插苗酶活性的影响

为了进一步探索各营养元素对林木生长的作用及其机理,促进新疆杨生产栽培技术的进一步发展,平衡目前生态建设对优势树种的需求。本文运用生物田间实验、化学分析、数理统计分析、酶学诊断等方法,研究了不同浓度的植物喷施灵处理对一年生新疆杨扦插苗多酚氧化酶(PPO)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性及其苗高、地径、生物量的影响。研究结果表明:植物喷施灵对新疆杨扦插苗的苗高、地径有明显的促进作用;对新疆杨体内的酶活性有不同程度的提高或抑制作用。     

IBDV超强毒株感染SPF鸡后法氏囊淋巴细胞凋亡及Bax和Bcl-2蛋白动态表达的研究

 为证实传染性法氏囊炎超强毒SNJ93株感染SPF鸡后1～14 d内法氏囊淋巴细胞中Bcl-2、Bax蛋白的动态表达与淋巴细胞凋亡的关系。应用透射电镜观察、TUNEL法标记检测凋亡的淋巴细胞，用免疫组织化学方法检测Bcl-2、Bax蛋白。结果表明，感染后1～7 d可见到大量凋亡的淋巴细胞，其中感染后3～5 d最多。感染后1～9 d Bcl-2蛋白显著高于同时点的对照组（P<0.01）；感染后1～5 d Bax蛋白明显高于同时点的对照组，差异极显著（P<0.01）；感染后第7天高于同时点的对照组,差异显著（P<0.05）； Bcl-2/Bax比率在感染后第1天低于同时点的对照组（P<0.05）；3～5 d明显低于同时点的对照组(P<0.01)。SNJ93感染SPF雏鸡后1～7 d内法氏囊淋巴细胞会发生大量凋亡，Bcl-2/Bax能准确反映淋巴细胞的凋亡程度。     

凡纳滨对虾无特定病原育苗试验

报道了凡纳滨对虾无特定病原 (SPF)育苗技术及养成试验效果。试验结果表明 ,平均单位水体出苗12 .88× 10 4ind/m3 ,育苗成活率 86 .15 % ;2 0 0 2年养成试验的对虾平均体重 34.318g/ind ,平均体长 14 .75 5cm/ind ,而对照池对虾平均体重 2 5 .793g/ind ,平均体长 13.0 33cm/ind。养成试验显示 ,放养优质无特定病原虾苗的池塘 ,平均可增产 4 6 .4 5 % ,成活率提高 7.4 6个百分点。     

蛋氨酸羟基类似物对感染法氏囊病毒鸡的肝脏生化指标的影响

通过测定SPF白来航蛋鸡的肝脏体重比、肝脏生化指标和酶活指标,研究家禽在感染法氏囊病毒(IBDV)引起免疫抑制的情况下液态蛋氨酸羟基类似物(HMA)对肝脏的影响。试验选取50只21日龄SPF蛋鸡随机分为5个处理,分别为攻毒的蛋氨酸缺乏组、正常蛋氨酸组(MET组)、蛋氨酸羟基类似物组,和未攻毒对照的蛋氨酸组和蛋氨酸羟基类似物组,每个处理10个重复。试验期为21d。结果表明:未攻毒情况下和攻毒情况下HMA组相对于MET组肝脏体重比均降低,且攻毒时差异显著(P<0.05);与MET组相比,HMA组在未攻毒情况下,肝脏的蛋白浓度相对高而攻毒时相对低,HMA组的肝脏的抗氧化能力不足;在攻毒情况下,HMA组相对于MET组肝脏的谷丙转氨酶(GPT)、碱性磷酸酶(APK)的酶活力显著增加(P<0.05)。     

Rederivation of a mutant line (prop 1) of zebrafish Danio rerio infected with Pseudoloma neurophilia using in vitro fertilization with eggs from pathogen-free wild-type (AB) females and sperm from prop 1 males

Along with the growing number of laboratories that work with zebrafish (Danio rerio), it is necessary to have animals with good sanitary quality. Specific pathogens can interfere with the experimental results and in the life quality of the animals. Pseudoloma neurophilia is a parasite with high potential for interference in behavioural, morphology, toxicological and genetic research, and is very common in zebrafish facilities. With that, we implemented a protocol for the pathogen elimination in a genetically modified lineage (prop 1) using eggs from specific pathogen-free (SPF) wild-type fish (AB line) for in vitro fertilization, along with water recirculation equipment disinfection, appropriate PCR screening and back crossing protocols. This resulted in SPF prop 1 heterozygotes, which allowed us to move forward with subsequent crossings to develop homozygote prop 1 mutants for our research. Hence, this demonstrates a useful strategy for an individual research laboratory to rederive a specific mutant free line that is not available from other SPF laboratories.     

Influence of maternal immunity on vaccine efficacy and susceptibility of one day old chicks against Egyptian highly pathogenic avian influenza H5N1

In Egypt, continuous circulation of highly pathogenic avian influenza (HPAI) H5N1 viruses of clade 2.2.1 in vaccinated commercial poultry challenges strenuous control efforts. Here, vaccine-derived maternal AIV H5 specific immunity in one-day old chicks was investigated as a factor of vaccine failure in long-term blanket vaccination campaigns in broiler chickens. H5 seropositive one-day old chicks were derived from breeders repeatedly immunized with a commercial inactivated vaccine based on the Potsdam/H5N2 strain. When challenged using the antigenically related HPAIV strain Italy/98 (H5N2) clinical protection was achieved until at least 10 days post-hatch although virus replication was not fully suppressed. No protection at all was observed against the Egyptian HPAIV strain EGYvar/H5N1 representing a vaccine escape lineage. Other groups of chicks with maternal immunity were vaccinated once at 3 or 14 days of age using either the Potsdam/H5N2 vaccine or a vaccine based on EGYvar/H5N1. At day 35 of age these chicks were challenged with the Egyptian HPAIV strain EGYcls/H5N1 which co-circulates with EGYvar/H5N1 but does not represent an antigenic drift variant. The Potsdam/H5N2 vaccinated groups were not protected against EGYcls/H5N1 infection while, in contrast, the EGYvar/H5N1 vaccinated chicks withstand challenge with EGYvar/H5N1 infection. In addition, the results showed that maternal antibodies could interfere with the immune response when a homologous vaccine strain was used.     

鸡瘟毒清对鸡新城疫病毒的抑制作用

采用中药制剂鸡瘟毒清(由金银花、黄芩、黄芪、黄连、丹皮等10余味中草药组成)对鸡新城疫病毒进行体内和体外抑制实验。体内抑毒实验选用21日龄艾拔益加肉鸡,随机分为5组,每组32只,直接攻毒,攻毒前7 d开始给药,直至35 d,测定治愈率;体外抑毒实验选用11日龄SPF鸡胚,随机分为3组,每组12枚,攻毒给药后感作30 min,继续孵化,测定保护率。结果显示,中药制剂鸡瘟毒清对鸡新城疫病毒有较好的抑制作用,其中体内抑毒实验高剂量组治愈率高达91%,体外抑毒实验保护率达66.7%。