传染性法氏囊病病毒超强毒株衣壳蛋白的可溶性表达、纯化与活性分析

为获得高质量的病毒衣壳蛋白VP2,本研究克隆了传染性法氏囊病病毒（infectious bursal disease virus,IBDV）超强毒株Gx的VP2基因,并亚克隆至载体pCold-Ⅰ,进而获得重组原核表达质粒pCold-Ⅰ-GxVP2,在Transetta（DE3）工程菌中优化条件进行IBDV衣壳蛋白VP2的可溶性表达,运用Ni-NTA亲和层析和凝胶过滤两种技术串联的方法进行蛋白纯化,运用单克隆抗体介导的Western blotting技术鉴定纯化蛋白的特异性,免疫SPF鸡鉴定纯化蛋白的免疫活性。结果显示,在冷休克条件下,IBDV衣壳蛋白VP2在Transetta（DE3）工程菌中实现了可溶性表达;通过纯化获得了高纯度的VP2,浓度为542 μg/mL;该蛋白不仅能与VP2单克隆抗体特异性反应,还能刺激鸡产生特异性免疫应答,具有良好的免疫活性。本研究在IPTG为1 mmol/L,15℃、120 r/min,诱导时间为24 h的条件下,实现了有免疫活性的IBDV衣壳蛋白VP2的可溶性表达和纯化。高纯度、可溶、具有功能活性的衣壳蛋白的制备,为深入开展IBDV致病机制研究奠定了基础。     

Soluble Expression,Purification and Activity Analysis of Capsid Protein of Very Virulent Infectious Bursal Disease Virus

To obtain the capsid VP2 with high quality, VP2 gene of very virulent infectious bursal disease virus (vvIBDV) Gx was cloned and inserted into pCold-Ⅰ and the prokaryotic expression plasmid pCold-Ⅰ-GxVP2 was constructed. In engineering bacteria Transetta(DE3), the induction conditions of protein VP2 expression were optimized.With affinity chromatography and gel filtration, protein VP2 was purified. With the monoclonal antibody directed Western blotting, protein VP2 was identified. Using SPF chicken, immunocompetence of VP2 was evaluated. The results showed that the dissoluble protein VP2 was expressed successfully in Transetta(DE3) in cold-shock conditions; Protein VP2 was purified and the concentration was 542 μg/mL; The purified protein VP2 not only reacted with the monoclonal antibody against protein VP2, but also induced specific immune response in immunized chickens. In general, with 15℃ of cold-shock condition, 120 r/min of shaking culture, 1 mmol/L of IPTG,inducting for 24 h, soluble capsid VP2 of IBDV with immunocompetence was successfully expressed and purified.The preparation of highly purified, soluble capsid protein with functional activity laid the foundation for further researches on the pathogenic mechanism.     

氮磷钾配施对田周地种植桂牧1号杂交象草产量及效益的影响

通过不同的施肥处理方案研究在田周地种植桂牧1号杂交象草Pennisetum purpureum cv.Guimu 1的氮、磷、钾需要量及其最佳配比模式。结果表明,在田周地种植桂牧1号杂交象草,通过合理的氮、磷、钾配方施肥,能够达到良好的生产效果与效益。实测结果以N2P2K2（氮肥414 kg/hm2,磷肥138 kg/hm2,钾肥276 kg/hm2)试验组的产量最高[（256.81±1.18）t/hm2],与其他低水平试验组差异均达到极显著水平(P<0.01);与无肥处理相比,增产率达到16.6%。通过对各处理进行效应模型的配置与分析,得出田周地种植桂牧1号杂交象草的预测最高产量为259 t/hm2,对应施肥量为氮肥414621 kg/hm2、磷肥140 kg/hm2、钾肥204 kg/hm2;预测最佳经济产量为256 t/hm2,对应施肥量为氮肥414 kg/hm2、磷肥140 kg/hm2、钾肥172 kg/hm2。     

松嫩平原苜蓿高产栽培技术研究

在松嫩平原,应用正交试验对苜蓿产量进行行距、灌水、施肥影响研究.结果表明,以30cm行距处理产草量最高,干草产量15389.66kg/hm2;灌水以3次和1次为好;施农家肥22500kg/hm2增产效果好于施磷酸二铵150kg/hm2和施复合肥150kg/hm2处理;施尿素112.5kg/hm2增产效果最佳,平均产干草14673.61kg/hm2;行距30cm、灌水3次、施磷酸二铵150kg/hm2、施氮肥112.5kg/hm2处理产干草19395.83kg/hm2,极显著高于其它处理.     

兔抗犬细小病毒2a型多克隆抗体交叉保护研究

为探究犬细小病毒（canine parvovirus,CPV）血清型只有一种的条件下,常用疫苗CPV-2型和CPV-2a病毒免疫血清抗体对国内流行CPV-2a病毒的中和率,试验将藏獒源CPV-2a毒株（10⁵ TCID₅₀/100 μL）和CPV-2（10^4.5 TCID₅₀/100 μL）疫苗接于F81细胞增殖,PEG6000法浓缩制成免疫原,各免疫新西兰长白兔3只,间隔2周1次,共免疫4次。收集血清纯化制备多克隆抗体,通过血凝抑制试验（HI）和血清中和试验（SN）分别用2种抗体中和CPV-2、CPV-2a病毒,对两者保护率进行初步评价,并对本地感染CPV-2a的4只犬,每组2只进行治疗,每日跟踪白细胞消长规律。结果显示,CPV-2a多抗中和国内流行病毒CPV-2a的HI抗体、中和抗体水平都极显著高于CPV-2多抗（P<0.01）,而中和CPV-2病毒的HI抗体、中和抗体水平两者差异不显著（P>0.05）,CPV-2a多抗组治疗能较快恢复正常值,2组白细胞数有显著差异（P＜0.05）。结果表明,CPV-2a多抗与常用CPV-2型疫苗免疫抗体相比能高滴度的中和CPV-2a,更适用于中国犬细小病毒的防制,对研发新型生物制品有一定意义。     

Prevalence and incidence of serum magnesium abnormalities in hospitalized cats

Total serum magnesium concentration ([Mg2+]s) was prospectively determined for 57 cats admitted to the intensive care unit (ICU) of the Cornell University Hospital for Animals. Data were collected and analyzed to determine the following: prevalence and incidence of [Mg2+] abnormalities, medical disorders associated with altered [Mg2+]s, association of altered [Mg2+]s with other electrolyte abnormalities, length of hospitalization for cats with abnormalities of [Mg2+]s versus those with normal [Mg2+]s, and survival of cats with abnormal [Mg2+)s versus those with normal [Mg2+]s. The point prevalence of magnesium abnormalities was 26%, the period prevalence was 46%, and the cumulative incidence was 23%. Hypermagnesemia was associated with abnormalities of serum potassium (P = .04) and phosphate (P = .01) concentrations. Abnormalities of [Mg2+]s were not associated with abnormal serum concentrations of Na+, Ca2+, or Cl-. On admission. hypomagnesemia was detected in cats with gastrointestinal, endocrine, and other disorders; hypermagnesemia was detected only in cats with renal disease, obstructive uropathy, or neoplastic disease. The median hospital stay for cats that developed abnormal [Mg2+]s after admission was longer than for cats that remained normomagnesemic (5 versus 4 days, respectively; P = .03). Despite the longer hospital stay, the survival of these cats was lower than that of normomagnesemic cats (54 versus 77%; P = .05). When all cats were considered, the survival of cats with abnormal [Mg2+]s also was decreased compared with normomagnesemic cats (62 versus 81%; P = .05). We conclude that abnormalities of [Mg2+]s may affect morbidity and mortality of affected cats.     

Sf9细胞PHB2蛋白的原核表达及其抗血清的制备

为了研究Sf9细胞PHB2蛋白(Sf-PHB2)的功能及其对虾白斑综合症病毒(WSSV)极早期基因ie1的转录调控作用,本研究从昆虫细胞Sf9中扩增sf-phb2基因编码区,克隆至表达载体pET30a中,转化到大肠杆菌BL21,IPTG诱导表达6His-Sf-PHB2重组蛋白.SDS-PAGE分析表明,表达的重组蛋白以...     

猪圆环病毒2型ORF2基因的原核表达及反应原性分析

研究猪圆环病毒2型(PCV2)Cap蛋白的抗原性,为开发PCV2的检测方法奠定基础。以PCV2CAU0673毒株的DNA为模板,扩增获得702bp的目的片段,扩增产物克隆入pET30a(+)原核表达载体,构建pET30a-PCV2-ORF2重组质粒,转入大肠埃希菌BL21(DE3);在37℃以1mmol/L IPTG诱导表达6h;采用Ni-NTA树脂亲和层析纯化重组蛋白,并用不同浓度的尿素对纯化蛋白进行复性。SDSPAGE分析表明,该ORF2编码基因在大肠埃希菌中得到表达,蛋白大小约为34ku;Western blot检测结果表明,该重组Cap蛋白与PCV2阳性血清发生特异性反应,与NA-PRRSV和PPV1血清不发生交叉反应。成功构建了PCV2-ORF2原核表达载体,实现了在大肠埃希菌中的表达,纯化后的复性蛋白具有较好的反应原性,为猪圆环病毒2型检测方法建立或试剂盒的开发奠定了基础。     

磺胺二甲嘧啶免疫抗原的合成研究

试验旨在研究磺胺二甲嘧啶（SM2）免疫抗原的合成。用重氮化方法将SM2分别与牛血清蛋白（BSA）和卵清蛋白（OVA）偶联,合成了免疫抗原SM2-BSA和包被抗原SM2-OVA。紫外扫描和聚丙烯胺凝胶电泳结果表明, SM2-BSA的紫外吸收光谱与BSA、SM2相比均发生了改变,证明偶联成功,并测得SM2-BSA的结合比为13∶1;用SM2-BSA免疫BALB/c小鼠,获得了高效价和特异的多克隆抗体。结果表明,半抗原SM2和载体蛋白偶联成功,并可获得高价、敏感的多克隆抗体。     

猪瘟疫苗中牛病毒性腹泻病毒2型的检测

为对上海某猪场送检的一份猪瘟疫苗进行牛病毒性腹泻病毒(BVDV)检测,本研究将猪瘟疫苗样品接种于MDBK细胞,盲传15代后仍无致细胞病变效应,但间接免疫荧光试验表明接种该疫苗后的MDBK细胞能够被单克隆抗体BZ-53(BVDV-2)识别。采用BVDV-1和BVDV-2的5’-UTR的通用检测引物和针对BVDV E2的引物,对样品RNA进行RT-PCR检测,结果显示,样品能够扩增出约288 bp的BVDV特异性片段;此外,5’-UTR和E2基因片段的测序分析结果表明分离株属于BVDV-2,并且其E2基因与牛源XJ-04株(BVDV-2)的E2基因同源性最高(92.3%),而与猪源ZM-95株(BVDV-1)的E2基因同源性较低(64.5%)。由此证明,该猪瘟疫苗中的确污染有一株BVDV-2株。     

猪Ⅱ型圆环病毒ORF2基因的克隆及其序列分析

根据 GenBank 中猪圆环病毒Ⅱ型(PCV- 2)ORF2基因序列,设计一对引物,应用PCR从疑似断奶仔猪多系统消耗综合征(PMWS)的死亡仔猪组织病料中扩增出 ORF2 基因(702 bp)。将此基因片段克隆入 pMD -18 T载体,筛选获得重组质粒 pMD ORF2 并对其测序,结果表明所克隆的ORF2基因与德国分离株AF201897核苷酸序列同源性为99.5%与其它PCV- 2 的 ORF2 核苷酸序列同源性在92.1%~99.9%之间,推导的氨基酸序列同源性在90.2%~99.5%之间。     

Association of porcine circovirus type 2 with vascular lesions in porcine pneumonia

The aim of this study was to evaluate the vasculature in porcine circovirus type 2-infected (PCV2-infected) lungs and to identify the PCV2 subtypes involved in porcine pneumonia. Pulmonary samples from 140 pigs, 2 weeks to 7 months of age, from 36 Hungarian commercial herds with clinical signs of respiratory disease were examined for the presence of respiratory pathogens, with bacterial culture, pathologic evaluation, and immunohistochemistry for PCV2, porcine reproductive respiratory syndrome virus, and swine influenza virus. PCV2 was the most commonly identified pathogen (49 cases) among the 74 of 140 cases (53%) with respiratory pathogens. PCV2 was detected immunohistochemically in the wall of 13% to 100% of pulmonary vessels (mean, 89%) in 38 of 49 cases (78%). Detection of PCV2 antigen was positively correlated with the presence of vascular lesions (P < .001, odds ratio [OR]: 159.54). Other pathogens capable of vascular injury in swine were found in 29 of 49 of the PCV2-positive cases (59%). The probability of detecting vascular lesions in PCV2-infected lung was higher than in infection with porcine reproductive respiratory syndrome virus (P < .002, OR: 14.63), Pasteurella multocida infection (P < .001, OR: 5.75), or Streptococcus spp. infection (not significant, OR: 1.45). Sequence analysis of open reading frame 2 amplicons was possible in 6 PCV2-positive cases, from which 5 cases proved to be PCV2b subtype and 1 case, PCV2a subtype. In conclusion, PCV2 antigen was commonly colocalized with pulmonary vascular lesions in pneumonia in Hungarian swine, and PCV2b was the dominant subtype.     

Arrhythmogenic effect of hypercapnia in ducks anesthetized with halothane

OBJECTIVE: To determine effects of hypercapnia on arrhythmias in ducks anesthetized with halothane. ANIMALS: 12 ducks, 6 to 8 months old, weighing 1.1 to 1.6 kg. PROCEDURES: Each duck was anesthetized with a 1.5% mixture of halothane in oxygen, and anesthetic depth was stabilized during a 20-minute period. We added CO2 to the inspired oxygen to produce CO2 partial pressures of 40, 60, and 80 mm Hg in the inspired gas mixture.The CO2 partial pressure was increased in a stepwise manner. When arrhythmias were not evident during inhalation of the gas mixture at a specific CO2 partial pressure, the CO2 partial pressure was maintained for 10 minutes before a sample was collected for blood gas analysis. When arrhythmias were detected, a sample for blood gas analysis was collected after the CO2 partial pressure was maintained for at least 2 minutes, and CO2 inhalation then was terminated. RESULTS: During the stabilization period, PaCO2 (mean +/- SD) was 33 +/- 5 mm Hg,and arrhythmias were not detected. In 6 ducks, arrhythmias such as unifocal and multifocal premature ventricular contractions developed during inhalation of CO2. Mean PaCO2 at which arrhythmias developed was 67 +/- 12 mm Hg. In 5 of 6 ducks with arrhythmias, the arrhythmias disappeared after CO2 inhalation was terminated. CONCLUSION AND CLINICAL RELEVANCE: Analysis of data from this study indicated that hypercapnia can lead to arrhythmias in ducks during halothane-induced anesthesia. Thus, ventilatory support to maintain normocapnia is important for managing ducks anesthetized with halothane.     

兔病毒性出血症病毒次要结构蛋白（VP2）的表达和细胞内定位分析

病毒蛋白VP2是兔出血症病毒（Rabbit Hemorrhagic Disease Virus,RHDV）的一种次要结构蛋白。本文旨在构建VP2与绿色荧光蛋白融合的真核表达载体,进而利用它研究VP2在细胞内的定位情况。首先在大肠杆菌中表达GST-VP2融合蛋白,然后用纯化的重组蛋白免疫小鼠制备抗VP2的抗血清。对制备的抗VP2抗血清进行特异性分析,再利用该抗体对转染pEGFP-VP2的BHK-21细胞进行检测,以研究VP2蛋白在细胞内的定位情况。结果表明,pEGFP-VP2转染BHK-21细胞后,不仅VP2蛋白得到了成功表达,而且通过检测偶联的绿色荧光蛋白可判断出VP2蛋白主要分布于BHK-21细胞的细胞质。本研究成功构建了VP2与绿色荧光蛋白融合的表达载体,并在真核细胞内实现了表达,通过检测荧光蛋白,发现VP2主要在细胞质内表达并分布,为深入探讨VP2的生物学功能奠定了基础。     

鸡传染性法氏囊病病毒rVP2蛋白高效组装亚病毒颗粒的鉴定

为获得高纯度的鸡传染性法氏囊病病毒（infectious bursal disease virus,IBDV）VP2蛋白自组装的亚病毒颗粒（subviral particles,SVPs）,并对重组VP2蛋白（rVP2）SVPs的组装效率和均一性进行评价,本试验利用大肠杆菌表达IBDV rVP2,通过SDS-PAGE和Western blotting对蛋白表达情况和免疫反应性进行鉴定,通过阴离子交换层析和切向流超滤浓缩系统纯化rVP2蛋白,并通过透射电镜（TEM）、高效液相尺寸排阻色谱（HPSEC）、蔗糖密度梯度离心及粒径和表面电位（Zeta potential）等多种检测技术对单个SVP组装形态和整体组装情况进行分析检测,初步建立了IBDV rVP2 SVPs组装效率的系统性检测方法。结果显示,在大肠杆菌中实现IBDV rVP2的大部分可溶性表达,且能与鸡IBDV阳性血清有明显的免疫反应性,纯化后rVP2纯度提高66.9倍,回收率达到93.3%。TEM观察rVP2自组装成直径约25 nm的SVPs,视野内SVPs大小均一,均匀分散。HPSEC检测结果显示,rVP2 SVPs的分子质量约为2 482 ku,与20个VP2三聚体形成的T=1二十面体SVPs分子质量一致。蔗糖密度梯度离心检测结果显示,rVP2 SVPs体积分布均一,组装效率高。粒径和Zeta电位检测结果表明,rVP2 SVPs颗粒分散度较好、体系稳定,有利于rVP2 SVPs的长期保存。本试验通过多种检测技术对rVP2 SVPs的组装情况进行检测分析,实现了rVP2 SVPs的高效组装,为IBDV SVPs疫苗的质量控制提供了有力支撑。     

Production of interferon by bovine peripheral blood monocytes infected with bovid herpesvirus 2

The production of interferon by bovine peripheral blood leukocytes infected with bovid herpesvirus 2 (BHV-2) was investigated in preparation for studying mechanisms of resistance to BHV-2. It was found that bovine peripheral blood monocytes produced high levels of interferon in response to BHV-2 inoculated at a multiplicity of 1. Virus-induced interferon was not stable at pH 2, was destroyed at 56 degrees C or by incubation with trypsin and was active against both vesicular stomatitis virus and BHV-2. Interferon of high specific activity was produced by incubating monocytes for 5 h with BHV-2 in serum-containing medium, replacing the inoculum with serum-free medium for an additional 16 h, and concentrating the serum-free medium by dialysis against dry polyethylene glycol. Interferon concentrations of 40,000 units per mg of protein were readily attained.     

A comparison of two oral rehydration solutions in experimental models of dehydration and diarrhoea in calves

Two oral rehydration solutions (ORS 1 and ORS 2) were evaluated in isolated intestinal loops of anaesthetised calves, in an experimental model of dehydration in the calf, in calves with experimentally induced diarrhoea and in 164 calves with clinical diarrhoea. The studies in isolated intestinal loops indicated that water absorption was significantly greater from ORS 2 than from ORS 1. After the intraperitoneal administration of hypertonic mannitol combined with intravenous diuretics, the plasma volume of calves was reduced by about 30 per cent, and was more rapidly expanded after treatment with ORS 2 than ORS 1. The plasma volume remained significantly reduced (P less than 0.01) three hours after dosing with ORS 1 whereas after treatment with ORS 2 it was not significantly different from the initial value. Acidosis was corrected to a significantly (P less than 0.01) greater extent after treatment with ORS 2, and peripheral perfusion also returned to normal more rapidly in calves given ORS 2. In newly purchased calves in which diarrhoea was induced experimentally with an E coli challenge, base deficit and diarrhoea were corrected more rapidly in the calves receiving ORS 2. When the solutions were tested in the treatment of 164 clinical cases of diarrhoea and dehydration there was no statistically significant difference in mortality between the formulations, although the overall mortality was 4.8 per cent in the calves treated with ORS 2, compared with 8.6 per cent in the calves treated with ORS 1. It was concluded that ORS 2 performed better than ORS 1 especially in the expansion of plasma volume and the correction of acidosis.     

乳酸锌对猪空肠上皮细胞IPEC-J2增殖及相关调控基因mRNA表达的影响

旨在探讨乳酸锌对猪空肠上皮细胞增殖及相关调控基因ZnT2、DMT1、IREG-1、MT1和ZIP4 mRNA表达的影响.用乳酸锌的锌浓度分别为50、100、150、200 mg·L-1的培养基培养IPEC-J2细胞,采用比色法测定分析细胞增殖变化；用实时荧光定量RT-PCR方法检测Zn T2、DMT1、IREG-1、MT1及ZIP4 mRNA表达,以TBPmRNA的表达水平作为内参对照.在细胞培养前36 h,乳酸锌对IPEC-J2细胞基本没有影响,随锌浓度递增细胞增殖幅度升高；乳酸锌处理IPEC-J2细胞后,Zn T2、DMT1、IREG-1及MT1 mRNA表达随锌浓度增高而升高,ZIP4 mRNA表达则随锌浓度增高而降低.添加乳酸锌可以促进IPEC-J2细胞增殖,上调ZnT2、DMT1、IREG-1、 MT1 mRNA表达,下调ZIP4 mRNA表达.     

猪圆环病毒Ⅱ型体外诱导3D4/2细胞炎症模型的建立

【目的】通过对猪圆环病毒Ⅱ型（PCV2）体外感染3D4/2细胞浓度、时间与细胞炎症水平进行探讨,建立PCV2体外感染3D4/2细胞炎症反应模型,以期为后期药物调控PCV2诱发3D4/2细胞炎症反应的研究奠定基础。【方法】将3D4/2细胞分为对照组及10⁰、10^-1、10^-2和10^-3 PCV2感染组,每组3个重复。对照组用DMEM培养,各PCV2感染组用不同稀释倍数PCV2液培养,2 h后均更换为含5%胎牛血清（FBS）的DMEM维持液进行培养,培养4、8、12和24 h后分别收集细胞及细胞上清液。采用Griess法检测一氧化氮（NO）水平,DCFH-DA荧光探针法检测活性氧（ROS）水平,酶标法检测还原型谷胱甘肽（GSH）水平,分光光度法检测黄嘌呤氧化酶（XOD）和髓过氧化物酶（MPO）活性,ELISA法测定白细胞介素-1β（IL-1β）、IL-6、肿瘤坏死因子-α（TNF-α）、IL-10、γ干扰素（IFN-γ）、IL-8、单核细胞趋化蛋白1（MCP-1）以及环氧合酶1（COX-1）和COX-2的分泌水平。【结果】10⁰至10^-3 PCV2作用4、8、12和24 h均能够成功感染3D4/2细胞。与对照组相比,10⁰ PCV2在感染3D4/2细胞4、8、12、24 h后ROS水平均极显著升高（P<0.01）,10^-1至10^-3 PCV2感染3D4/2细胞8、12、24 h后ROS水平显著或极显著升高（P<0.05;P<0.01）;10⁰至10^-3 PCV2感染3D4/2细胞8、12、24 h后,细胞内NO浓度及MPO活性显著提高（P<0.05）,细胞上清液中的IL-1β、IL-6、TNF-α、IL-10、IFN-γ、IL-8和MCP-1水平及COX-1活性均显著或极显著升高（P<0.05;P<0.01）,其中10⁰ PCV2感染3D4/2细胞后,各炎症因子水平上升最显著,且随着时间的延长,NO浓度逐渐升高,XOD活性逐渐降低。【结论】PCV2可诱导3D4/2细胞炎症反应,且10⁰ PCV2体外感染3D4/2细胞4~12 h是建立炎症模型的最佳条件。