ICHV在MDCK细胞上增殖的研究

采用免疫组化ＢＡ法进行了犬传染性肝炎病毒（ＩＣＨＶ）在ＭＤＣＫ细胞上定位的研究．结果表明，接毒后１０小时可见细小阳性反应颗粒出现于肿胀的病变细胞核中．ＨＥ染色所见包涵体形态与临床发病犬肝实质细胞包涵体形态相似，提示可能是ＩＣＨＶ感染细胞所引起的特征性变化．同时测定的病毒血凝滴度结果表明，包涵体的形成与病毒增殖有一定关系，８４～９６小时收毒较为适宜．     

ICHV在MDCK细胞上增殖的研究

采用免疫组化ＢＡ法进行了犬传染性肝炎病毒（ＩＣＨＶ）在ＭＤＣＫ细胞上定位的研究。结果表明，接毒后１０小时可见细小阳性反应颗粒出现于肿胀的病变细胞核中，ＨＥ染色所见包涵体形态与临发病犬肝实质细胞包涵体形态相似，提示可能是ＩＣＨＶ感染细胞所引的特征性变化。同时测定的病毒血凝滴度结果表明，包涵体的形成与病毒增殖有一定关系，８４～９６小时收毒较为适宜。     

猪痘病、水疱病、口蹄疫的鉴别和诊断

1猪痘病 病原该病可由两种相似的病毒引起,一是猪痘病毒,它只引起猪发病,只在猪源组织细胞内增殖,并在细胞核内形成空泡和包涵体.第二是痘苗病毒,可以使猪和其他动物感染,能在牛、人、绵羊等动物的胚胎细胞内增殖,并在被感染的细胞内形成包涵体.     

柞蚕蛹增殖核型多角体病毒的研究

柞蚕蛹增殖核型多角体病毒的研究谢秉泉，周怀民，郑作运（河南省云阳蚕业试验场）在Ｓｍｉｔｈ（１９８３）、前田进（１９８４）取人干扰素基因分别与苜蓿尺蠖核型多角体病毒ＤＮＡ（Ａｕ－ｔｏｇｒａｐｈａｃａｌｉｆｏｒｎｉｃａＮＰＶ－ＤＮＡ）和家蚕核型多角体病毒...     

柞蚕蛹卵巢细胞的离体培养及其病毒感染试验

对柞蚕蛹卵巢细胞进行离体培养,原代培养出现细胞聚集中心,生长良好的卵巢原代培养细胞一般在1—2个月由可以形成细胞单层进入传代培养。培养的细胞多为圆形上皮样细胞,并以哑铃状、棱形及分枝伸展的方式进行增殖。其原代培养20天以上的单层细胞对同源的柞蚕核型多角体病毒很敏感。病毒接种3—4天后,细胞出现明显的致病变现象,5—6天后,大部分细胞核内形典型的多角体,8天以后核内多角体成熟,致使细胞破裂而释放到培养基中。而且感染后的细胞培养物回接蛹体和原代细胞仍具感染力。     

柞蚕核型多角体病毒对柞蚕蛹的感染性试验

苜蓿银纹夜蛾核多角体病毒(AcNPV)和家蚕核型多角体病毒(BmNPV)载体表达系统的建立,使数百种外源基因得到高效的表达.该系统的产业化开发如大量培养昆虫细胞,存在成本高、技术难度大等问题.建立柞蚕核型多角体病毒(Antheraea pernyi nuclear polyhedrosis virus ,ApNPV)载体表达系统,是利用柞蚕蛹为宿主进行外源基因表达.我国柞蚕资源丰富,柞蚕的蛹体大,以蛹滞育越冬,能够满足工厂化生产的需求.柞蚕核型多角体病毒有3个不同亚株,本实验研究了ApNPV A株系[简称ApNPV(A)]对不同发育阶段和不同品种的柞蚕蛹的感染性,为利用柞蚕蛹表达外源基因的产业化开发奠定基础.     

FMDV免疫活性串联片段FA的表达及免疫原性测定

将口蹄疫病毒免疫串联片段FA克隆至原核表达载体pBAD/TOPO中,经鉴定后得到重组质粒pBAD-FA,将此重组质粒转化到受体菌TOP10中,用诱导剂阿拉伯醛糖分别以不同的浓度进行诱导,并在不同诱导时间进行采样,经处理后做SDS-PAGE、Westem blot分析.结果发现以终浓度为O.002%的阿拉伯醛糖进行诱导,4 h后表达可达到高峰,其大小约为23 kD,软件扫描结果显示,FB融合蛋白的表达量占细菌总蛋白的29.3%,能与抗FMDV抗体发生特异性反应,融合蛋白以包涵体和可溶形式存在.将融合蛋白的可溶性组分用50%Ni-NTA树脂过柱纯化并抽提融合蛋白的包涵体,经过洗涤后分别制成油乳剂疫苗,经皮下注射免疫豚鼠,用乳鼠中和试验测定豚鼠血清中和指数,并用口蹄疫病毒对豚鼠进行攻毒.结果表明,用此融合蛋白可溶部分的纯化产物和包涵体免疫豚鼠能诱导产生高滴度的中和抗体,对病毒的攻击分别提供100%和75%的免疫保护.     

鸡包涵体肝炎的诊断与防制

正包涵体肝炎是由禽腺病毒引起鸡的一种急性传染病,以突然死亡、严重贫血、黄疸、肌肉出血、肝炎和肝细胞内形成核内包涵体为特征。1病原体包涵体肝炎病毒属于腺病毒科、禽腺病毒属,病毒粒子直径为80~90nm,无囊膜,呈正20面体对称,为双股DNA病毒。鸡腺病毒有11个血清型。该病毒对外界环境的抵抗力较强。耐热,50℃3小时稳定,在     

犬传染性肝炎病毒的形态发生学及抗原定位研究

应用免疫金电子显微镜技术研究了犬传染性肝炎病毒(ICHV)在犬肾传代细胞内的增殖过程及其病毒抗原在感染细胞内外的定位.结果显示:(1)吸附在细胞膜表面的病毒粒子,主要通过细胞吞饮作用侵入细胞,而吸附在微绒毛膜表面的病毒粒子则可直接“渗入”细胞;(2)在病毒感染不同时用的细胞核内观察到均质型、微粒型、颗粒型、副晶格型、病毒包涵体型及致密型等6种类型包涵体,其中前5种能被免疫金标记,它们是尚未形成病毒粒子的抗原蛋白、病毒装配后剩余的抗原蛋白或ICHV的病毒粒子结晶,致密型包涵体未被免疫金标记,可能是病毒DNA;(3)感染细胞内出现的某些特殊结构均不具有病毒抗原性,其中纤维样结构和管状结构在病毒增殖过程中起支持作用.     

柞蚕围食膜及其对核型多角体病毒灭活力的测定

<正>围食膜(peritrophic membrane)是昆虫消化和吸收过程中,极为重要的机构之一.对于包括家蚕在内的其它昆虫的围食膜,已有过一些研究和报道.昆虫围食膜的特异结构及组成物质的性质,是昆虫自身的一种对外的防御屏障.不仅消化液对经口进入昆虫肠腔内的各种病原物具有很强的抗御能力,围食膜也对昆虫起着保护作用.但是,对于柞蚕围食膜及其机能,尚少见报道.我们在研究核型多角体病毒对柞蚕中肠侵染和增殖的过程中,对围食膜的形态及对病毒的灭活力做了初步观察和测定.     

微粒子病家蚕消化道内肠球菌的分布

从健康家要、感染微粒子病家蚕,以及感染细菌性肠道病家蚕的消化道分离了200株肠球菌,并进行了数值分类学鉴定,以探讨家蚕消化道中肠球菌的生态学分布和家蚕微孢子与肠球菌的相互关系。研究结果表明:与健康蚕相比,4龄或5龄起蚕添食微孢子的微粒子病家蚕消化道内,肠球菌的数量分别增加5.5×10~5倍和0.74×10~2倍;菌种数从6个分别下降为3个和4个;生化表型数从27个分别下降为13个和14个;在菌种分布上,Ent.avium的分布频率从健康蚕的56％分别下降至20%和38%,而Ent.faecium的分布频率从健康蚕的2％分别上升至40％和16%;分离菌株共有59个生化表型。     

用原子荧光法检测家蚕体内硒的含量及其分布

硒对动物生殖发育、免疫系统具有重要功能,是动物必需微量元素。采用原子荧光法对不同系统家蚕体内硒的含量及其分布进行测定,结果显示:在喂食相同桑叶的情况下,不同系统家蚕品种幼虫体内的硒含量存在显著差异,5龄第4天的中系家蚕品种幼虫体内的硒含量明显高于日系家蚕品种,其中中系家蚕品种19-570体内的硒含量最高。对家蚕品种大造体内硒分布的研究结果表明:精巢中的硒含量明显高于其他组织,头部次之,脂肪体中的硒含量相对较低,由此推测硒在家蚕的生殖发育过程中可能发挥着重要作用。     

Virulence analysis of a Salmonella gallinarum strain by oral inoculation of 20-day-old chickens

In order to know the effect of in vitro passages on the pathogenicity of the Salmonella gallinarum strain INTA 91, a lyophilized culture was compared with the same strain recently isolated from a sick bird. The mean lethal dose (LD50) of the orally administered lyophilized culture was determined as 2.04 x 10(8) colony-forming units (CFU)/chicken. There was no correlation between the LD50 dose and the degree of disease produced; doses 10 or 100 times higher than the calculated LD50 did not produce a more severe disease. In trial 1, chickens were challenged with 1.02 x 10(9) CFU per chicken (5LD50) of the lyophilized strain and reached 52.2% mortality at the end of the assay. In trial 2, three different groups of chickens were infected with a recent isolate of the same strain: 2.04 x 10(8) CFU/chicken, 4.1 x 10(8) CFU/chicken, and 2.1 x 10(9) CFU/chicken (i.e., 1LD50, 2LD50, and 10LD50 of the dose calculated for the lyophilized strain, respectively). These chicken groups presented higher mortality rates (90%, 100%, and 95%, respectively) than previous trials, showing that the S. gallinarum strain used here increased its virulence by in vivo infected chicken passage. In all assays, the disease started after an incubation period of around 5-6 days. To obtain reliable and reproducible results in future challenge experiments, a fixed limited number of in vitro passages of the S. gallinarum strain must be determined.     

苦豆子总碱对小鼠急性毒性试验研究

采用改良寇氏法测定苦豆子总碱提取物对小鼠腹腔注射的急性毒性,评价其安全性,为临床安全用药提供依据。给试验组小鼠灌服不同浓度的苦豆子总碱提取物,观察给药后小鼠的临床表现与死亡情况,采用改良寇氏公式计算LD50及LD50的95%可信限,结果表明,苦豆子总碱经腹腔注射的LD50为559.24 mg/kg,95%可信限为471.95-663.59 mg/kg。试验结果提示,苦豆子总碱的毒性较低,临床用药安全可靠。     

氰氟虫腙对家蚕的毒性

氰氟虫腙是一种最新开发的具有高度选择性杀虫剂,主要用于蔬菜和水稻等作物防治鳞翅目和鞘翅目害虫。为了明确该药剂在蚕区使用对养蚕业的安全性,采用食下毒性测定和田间残毒期试验。结果表明:氰氟虫腙对3龄起蚕的摄入致死中浓度(LC5)0为0.6605mg/L,95%置信限为0.6196～0.7094mg/L;240g/L氰氟虫腙悬浮剂750倍、1500倍和3000倍稀释液田间喷雾桑叶,间隔70d后饲喂3龄蚕的死亡率均为100%,一般在添食毒叶后1～3d中毒死亡,主要症状表现为:食桑减缓、静伏、少量吐液、腹部缩短等。氰氟虫腙对家蚕的急性毒性较强,在桑叶上的残毒期极长,超过正常情况下的桑叶叶龄,桑园周围其它农作物应谨慎使用该杀虫剂。     

克蚧威农药对家蚕的毒力及残效期研究

本文介绍了克蚧威对家蚕的毒力和残效期.结果表明:克蚧威对家蚕有很强的触杀作用,秋季对三龄蚕的触杀毒力回归方程为Y=2.458十1.862X,Lc_(50).为23.185ppm,LD_(50)为0.012ug/头,春季800倍液喷桑叶对家蚕的安全间隔期为10天.蚕对克蚧威的抗性因蚕龄大小和季节不同有异.     

Large-scale production of porcine mature interleukin-18 (IL-18) in silkworms using a hybrid baculovirus expression system

In this report, a hybrid baculovirus expression system, which means a hybrid virus of the Autographa californica nuclear polyhedrosis virus and the Bombyx mori nuclear polyhedrosis virus, was used for the large-scale production of porcine mature interleukin-18 (IL-18) in silkworms. Two recombinant hybrid baculoviruses containing cDNA of the porcine precursor IL-18 and the porcine caspase-1 were constructed and were used to infect silkworm larvae. After the co-infection of the two viruses, porcine mature IL-18 was efficiently produced in the haemolymph. The concentration of IL-18 in the haemolymph was 80-100 microg/ml, as determined by porcine IL-18 specific ELISA. This yield was twenty-times more than that of the insect cell expression system described previously. The porcine mature IL-18 produced by the silkworms strongly induced interferon-gamma (IFN-gamma) production from porcine PBMC. An insect factory system for the large-scale production of useful cytokines for livestock animals will be available in the near future.     

Passive protection against porcine epidemic diarrhea (PED) virus in piglets by colostrum from immunized cows.

The effects of hyperimmune cow colostrum (HCC) on experimentally induced porcine epidemic diarrhea (PED) were investigated in piglets. In experiment 1, four 2-day-old piglets fed HCC containing an antibody titer of 1:512 and another four piglets fed unimmune cow colostrum (UCC) were orally inoculated with 10LD50 of PED virus. The piglets were given colostrum three times a day at 4 hr intervals. Half of the piglets fed HCC showed diarrhea and recovered, and all piglets survived. In contrast, all piglets fed UCC developed diarrhea and three of them died. In experiment 2, 2-day-old piglets fed HCC containing antibody titers of 1:512, 1:128 and 1:32, and UCC were inoculated with PED virus, and survival rates after challenge were 100, 75, 50 and 0 %, respectively. In experiment 3, 1-day-old piglets fed HCC with 1:512 antibody titer or UCC were inoculated and necropsied at 24, 48 and 72 hr after the inoculation for pathological examination. Piglets fed HCC remained healthy and PED virus antigen was not detected in the epithelial cells of the small intestine, and the length of the villi in small intestine was normal. On the other hand, in piglets fed UCC, villous atrophy and PED virus antigen were observed in epithelial cells of the jejunum and ileum from 24 hr. It was concluded that oral administration of HCC to piglets was effective in preventing PED virus infection and reduced their mortality.     

Pharmacokinetics of ticarcillin in the loggerhead sea turtle (Caretta caretta) after single intravenous and intramuscular injections.

Three captive loggerhead sea turtles, Caretta caretta, were used in four trials, one i.v. and three i.m., to determine the pharmacokinetic properties of a single dose of ticarcillin. For the i.v. study, each turtle received a single 50 mg/kg dose and blood samples were collected at 0, 0.5, 1, 2, 4, 6, 8, and 12 hr and at 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, and 14 days after administration. For the i.m. study, each turtle received one of three dosages (25, 50, or 100 mg/kg) in a randomized complete block design and blood samples were collected at the same time intervals. Each trial was separated by a minimum of 28 days to allow for complete drug clearance. Drug concentration in plasma was determined by a validated liquid chromatography-mass spectrometry assay. For the i.v. study, the elimination half-life was 5.0 hr. The apparent volume of distribution and plasma clearance were 0.17 L/kg and 0.0218 L/hr/kg, respectively. For the i.m. study, mean time to maximum plasma concentrations ranged from 1.7 ( +/- 0.58) hr in the 50 mg/kg group to 3.7 (+/- 2.5) hr in the 100 mg/kg group. Mean bioavailability ranged from 45% ( +/- 15%) in the 50 mg/kg group to 58% (+/- 12%) in the 100 mg/kg group, and the mean residence time ranged from 7.5 ( +/- 2.6) hr in the 25 mg/kg group to 16 (+/- 6.8) hr in the 100 mg/kg group. Two turtles had slight alanine aminotransferase elevations that were not clinically apparent at two different dosages, but otherwise, blood chemistries were unaffected. Possible i.m. dosage regimens for loggerhead sea turtles are 50 mg/kg q24 hr or 100 mg/kg q48 hr. Liver enzymes should be monitored during treatment.     

Body fluid concentrations and pharmacokinetics of chloramphenicol given to mares intravenously or by repeated gavage

Serum concentrations and the pharmacokinetics of chloramphenicol were determined in 6 healthy mares after a single IV administration (50 mg/kg of body weight) or after the 1st and 5th sequential intragastric (IG) administration (50 mg/kg/6 hours) of chloramphenicol. Synovial fluid, peritoneal fluid, CSF, and urinary concentrations of chloramphenicol after the IG administrations also were determined. Mean (+/- SEM) overall elimination rate constant (K) values for the IV, 1st IG, and 5th IG dosages were 0.42 +/- 0.064/hr, 0.42 +/- 0.049/hr, and 0.29 +/- 0.074/hr, respectively, and were not significantly different from one another (P greater than 0.05). Bioavailability was 40 +/- 8.6% after the 1st IG administration and was 21 +/- 5.2% after the 5th IG administration. Values for the area under the curve (AUC) for the 1st and 5th IG dosages were significantly different from the AUC value for the IV dosage, and the AUC value for the 5th IG dosage was significantly different from that for the 1st IG dosage. Chloramphenicol was administered to 2 mares in 6 consecutive doses; the first and last doses were given IV and the others were given IG. Mean K values after the 2 IV doses were 0.38 +/- 0.112/hr and 0.56 +/- 0.078/hr, which were not significantly different from each other or from the mean value for the IV dosage given to all 6 mares. Absorption of chloramphenicol decreased with repeated IG administrations, resulting in lower concentrations of chloramphenicol with subsequent administrations. Five consecutive IG doses of chloramphenicol were administered to 4 of the mares in a separate experiment and did not alter intestinal xylose absorption.