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1.
禽波氏杆菌内毒素致病性的研究   总被引：8，自引：0，他引：8  
本研究利用热酚水法从营养琼脂培养基上生长的禽波氏杆菌菌苔提取其内毒素精品,用此提取物通过家兔Ｓｈｗａｒｔｚｍａｎ试验及鸡胚、雏鸡和小白鼠接种试验,对禽波氏杆菌内毒素的致病性进行研究探讨。试验结果表明：该内毒素对鸡胚、小白鼠的致病性较强,而雏鸡、家兔具有较强的抵抗力,但各种发病死亡动物的病变特征、病变性质、致死原因基本一致,均表现为急性败血症性病变,心、肝、肾、肺等多器官功能急性衰竭是致死动物的主要  相似文献   

2.
Chickens and rabbits were injected intradermally with an endotoxin, namely Escherichia coli lipopolysaccharide (LPS). Twenty-four hours later, LPS was again administered intravenously to induce a local Shwartzman reaction. A typical cutaneous inflammatory reaction developed in rabbits, but not in chickens. Even very high doses of LPS, that made the birds visibly sick, failed to elicit the reaction. The results suggest that chickens are refractory to the Shwartzman reaction. A noteworthy feature of the chickens' response to intradermal endotoxin was the formation of prominent perivascular lymphoid aggregates.  相似文献   

3.
Strain Y3343 isolated from a goat with septicemia and polyarthritis was studied. The strain was virulent and induced septicemia, polyarthritis and coagulopathy in two goats. Limulus amebocyte lysate active material was present in plasma, but not in higher titre in inoculated goats. Sonicated mycoplasma material induced a dramatic somatic cell response in the mammary gland of cows and goats and marked clotting of the cows' milk, but it did not clot limulus amebocyte lysate or kill chick embryos. Phenol-water extract clotted limulus amebocyte lysate and induced somatic cell response in cows but not in goats. The phenol-water extract did not kill chick embryos, was not pyrogenic in rabbits or goats, and did not induce generalized Shwartzman reaction or change the leukocyte kinetics in rabbits. It therfore appears that the virulence mechanisms of strain Y3343 can not be explained on the basis of factors with strong endotoxin activity.  相似文献   

4.
A herpesvirus was isolated from tumours of the ethmoidal mucosa in two of three head of cattle in the State of Kerala, India. The virus designated M40 was cytopathic for a variety of cultured bovine and porcine cells and it did not kill suckling mice or chicken embryos. Sera from tumour-bearing cattle and goats reacted with the M40 virus. Immunofluorescence tests with FITC-conjugated IgG from a bovine monospecific antiserum to bovine herpesvirus 4 (BHV-4) stained the M40 virus specific antigen in infected cells. Experimental infection of goats with the M40 virus did not result in development of tumours. This virus is therefore considered to represent a "passenger" virus. A great similarity was found between restriction patterns of DNAs extracted from M40 virus and the strain 66-P-347, a reference strain of the BHV-4 group.  相似文献   

5.
The endotoxic activity of Fusobacterium necrophorum bov 5 was investigated. The supernatant (S) fluid and cell wall (CW) preparation, obtained after differential centrifugation of the ruptured cell mass, were lethal for mice. The toxicity of the S fluid was stable during prolonged storage, treatment with formalin, and heating for 15 minutes at 80, 100, and 121 C, but was destroyed by alkaline hydrolysis with 0.25 N NaOH. The toxic factor was found in a high molecular weight (MW) fraction after gel filtration. The properties exhibited by the toxic S fluid resembled those of endotoxic lipopolysaccharide (LPS). Extracted and partially purified LPS (endotoxin) from F necrophorum bov 5 demonstrated a mouse median lethal dose (mouse LD50) of 16.8 mg/kg of body weight. The toxic LPS material, a high molecular weight moiety as estimated by gel filtration, was resistant to ribonuclease (RNase), deoxyribonuclease (DNase), and pronase treatment. A positive Shwartzman reaction (median skin lesion dose (SLD50) equal to 3.32 mug/kg of body weight) and biphasic fever response (minimal dose required to produce a fever index of 40 sq cm which falls on the linear portion of dose-response curve (FL40) equal to 0.41 mug/kg of body weight) further indicated the toxin was endotoxin in nature. The LPS from F necrophorum bov 5 was less toxic than Salmonella typhimurium LPS; but had considerable toxicity for experimental animals. The toxic activity of the partially purified F necrophorum bov 5 endotoxin was separated into 2 fraction regions by diethylaminoethyl (DEAE)-cellulose chromatography. The data provide evidence for the production of a potent endotoxin, possibly composed of more than one toxic component, which may be released upon cell disruption.  相似文献   

6.
To study the possible role of endotoxin in the pathogenesis of bovine laminitis, local and systemic injections of endotoxin (E. coli 0111 B4) with different doses were given to three groups of four cows each. Clinical and haematologic parameters indicated an acute-phase response, including positive plasma ethanol gelation (soluble fibrin), the occurrence of fibrin degradation products and decreased thrombocyte counts. Local Shwartzman reactions were not evoked. Clinical examination of the claws and the gait of the animals revealed no signs of laminitis. However, on histopathological examination of the claw corium signs of laminitis such as vacuolisation of the Stratum basale, lymphocyte and leucocyte infiltration and thrombosis were found. These results indicate that endotoxin indeed may be involved in the pathogenesis of laminitis. For the development of a clinical acute laminitis model in cattle either another dosage, other toxins or factors in addition to the endotoxin used in this experiment are needed.  相似文献   

7.
To determine whether infection with Mycoplasma bovoculi increases ocular colonization of cattle eyes with Moraxella bovis and other bacteria, colonization of ocular gram-negative bacteria were measured in eyes of cattle infected with Mycoplasma bovoculi. Strains of Moraxella ovis were chosen because these are among the most commonly isolated species of gram-negative bacteria from cattle eyes. Five strains of M ovis were characterized biochemically and by pilus structure, permitting the recognition of 2 biotypes. All strains were tested in a mouse corneal pathogenicity model. One strain of each biotype was selected for testing in calves. All 5 strains were apathogenic for mice, and the 2 strains tested in cattle did not induce keratitis. Infection of calves with Mycoplasma bovoculi increased the amount and persistence of colonization with the strains of M ovis.  相似文献   

8.
Studies of turkey poult responses to Pasteurella multocida endotoxins indicated that lipopolysaccharide (LPS) preparations from two highly pathogenic strains and free endotoxin from one of these strains were all similar in lethal toxicity. Lethal intravenous doses were generally high, 1 mg or more for 1-week-old poults (13.3 mg/kg). The toxic effects of LPS were not increased by repeated administration of small hourly doses. For both forms of endotoxin, the relationship between dose and response was considered erratic. Attempts to increase the susceptibility of poults to LPS by administering a liver-damaging substance (galactosamine) or a histamine-releasing substance (compound 48/80) or by performing surgical bursectomy were not effective. The LPS did not provoke a dermal Shwartzman reaction, even though doses used were 10 times those that produced a characteristic reaction in a rabbit.  相似文献   

9.
Sporadic spreads of swine-origin influenza H3N2 variant (H3N2v) viruses were reported in humans, resulting in 437 human infections between 2011 and 2021 in the USA. Thus, an effective vaccine is needed to better control a potential pandemic for these antigenically distinct viruses from seasonal influenza. In this study, a candidate vaccine strain with efficient growth capacity in chicken embryos was established through serial blind passaging of A/Indiana/08/2011 (H3N2)v in mice and chicken embryos. Seven amino acid substitutions (M21I in PA; A138T, N165K, and V226A in HA; S312L in NP; T167I in M1; G62A in NS1 proteins) were found in the passaged viruses without a major change in the antigenicity. This mouse- and egg-adapted virus was used as a vaccine and challenge strain in mice to evaluate the efficacy of the H3N2v vaccine in different doses. Antibodies with high neutralizing titers were induced in mice immunized with 100 µg of inactivated whole-virus particles, and those mice were significantly protected from the challenge of homologous strain. The findings indicated that the established strain in the study was useful for vaccine study in mouse models.  相似文献   

10.
A el-Zein 《Avian diseases》1986,30(4):825-828
A highly virulent Newcastle disease virus (SA84) was isolated from a large broiler operation in Saudi Arabia. The mean death time of chicken embryos given the minimum lethal dose, the pathogenicity of the isolate for 8-week-old chickens, the plaque characteristics, and the intracerebral pathogenicity index indicated that the isolate is of the viscerotropic velogenic pathotype.  相似文献   

11.
鸡传染性支气管炎病毒LH2/01/10的分离鉴定   总被引：1，自引：0，他引：1  
2001年在我国黑龙江省某鸡场疑似鸡传染性支气管炎的发病鸡群中，分离到一株病毒，将该病毒接种10日龄SPF鸡胚，取72h的尿囊液进行电镜观察并用1％胰酶处理，结果发现尿囊液中存在典型的冠状病毒，用胰酶处理过的尿囊液能凝集SPF鸡的红细胞，初步鉴定为鸡的传染性支气管炎病毒。将该病毒尿囊液再次接种10日龄SPF’鸡胚，通过病毒对鸡胚的致病作用、病毒超微形态特征以及病毒凝集鸡红细胞的特性等对该毒株进行研究，结果表明：经胰酶处理后的病毒尿囊液可凝集鸡红细胞。鸡胚的第二代病毒尿囊液(命名为LH2,／01／10)分别接种1日龄和15日龄的SPF鸡，发现对不同日龄的鸡表现不同的致病性，对1日龄接种鸡和同笼饲养的同居对照鸡致病力高，发病率为11／11，致死率分别为4／6和2／5；15日龄接种和同居感染鸡发病率为9／9，致死率分别为1／5和1／4。实验应用反转录一聚合酶链式反应技术对LH2／01／10的膜蛋白基因进行扩增、克隆和序列测定，结果表明该基因具有IBVM基因的共有分子特征．与IBV标准株M41的M基因核苷酸的同源性为90％，氨基酸的同源性为91％。这从分子水平进一步证实引起鸡群死亡的病毒为鸡传染性支气管炎病毒。  相似文献   

12.
Studies were undertaken to assess the chicken embryo and newly hatched chicken as models for studying the effects of bone-active agents. Initially, 1,25-dihydroxycholecaliferol (1,25[OH]2D3), sodium fluoride (NaF), parathyroid extract, epidermal growth factor, and prostaglandin E2, were tested for lethality over a broad dose range. One or 3 injections of 1,25(OH)2D3 into the yolk sac of chicken embryos resulted in death of embryos given greater than or equal to 0.1 ng/injection, whereas 0.01 ng was tolerated by the embryos. Administering 1,25(OH)2D3 intraperitoneally to newly hatched chickens as a single injection or weekly for 3 weeks resulted in no deaths at doses up to 50 ng. One or 3 IV injections of 800 micrograms of NaF were lethal to embryos, whereas injections of less than or equal to 400 micrograms were tolerated by the embryo. Giving chickens feed and water containing 2.4 g of NaF/kg was lethal, but no deaths occurred when chickens were given feed containing less than or equal to 1.2 g of NaF/kg. Mortality associated with the administration of epidermal growth factor to embryos was inconsistent, in that death occurred in embryos given a single injection of greater than or equal to 250 ng, but no deaths occurred in embryos given 3 injections at similar doses. Parathyroid extract and prostaglandin E2 were not lethal when administered to embryos and chickens in a single-injection or multiple-injection regimen. Overall, lethality in chicken embryos given a particular agent reflected the dose of bone-active agent injected, rather than the number of injections. Three of the bone-active agents were selected to characterize their microscopic bone effects in chicken embryos and chickens.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

13.
QU分离株是一株类似产蛋下降综合征病毒,属于鸭腺病毒1型病毒。通过人工感染和细胞增殖试验,结果显示QU分离株接种无特定病原雏鸡未出现临床病症及生长发育障碍,不致死鸡胚,对鸭胚的致死率明显比引起产蛋下降的HS株低。QU株在鸡胚肝细胞、鸭胚成纤维细胞及鸡胚成纤维细胞上生长良好,产生典型细胞病变,且在鸡胚肝细胞上的增殖滴度最高,但不适应鸡胚肾细胞。这些数据说明QU株系对鸡具有低毒力的腺病毒,有可能用作禽用基因疫苗或基因治疗的候选病毒载体。  相似文献   

14.
Strained ruminal fluid from cattle fed hay or grain was lethal to mice when injected intraperitoneally, but the fluid from grain-fed cattle was approximately 3.7 times more toxic than that from hay-fed cattle. The lethal factor(s) was not resistant to heat, was nondialyzable, was retained on Seitz and membrane filters, and was associated with the bacterial fraction of ruminal fluid. We concluded that death of the mice resulted from infection produced by facultative bacteria normally in ruminal fluid. Ruminal fluid from grain-fed cattle contained a greater number of facultative bacteria than did that from hay-fed cattle.  相似文献   

15.
Agents lethal to chicken embryos and mice were isolated from the blood and spleen of 2 muskrats and 2 snowshoe hares which died during the cataclysmic die-off of 1961 in Central Saskatchewan. The 4 isolates are probably identical. One of them was identified as a member of the psittacosis-lymphogranuloma venereum (PLV) group of organisms on the basis of morphological and tinctorial properties and on the possession of group specific antigens. Application of the method of specificity differences permitted its serotype differentiation.  相似文献   

16.
本试验旨在通过对内蒙古绒山羊骨骼肌中氨基酸含量进行测定,并与之前文献报道的绵羊、牛、猪、鸡骨骼肌中氨基酸含量进行检测比较并分析。结果显示,试验检测的7种必需氨基酸含量物种间差异较大,但总含量都在35%以上,含量从大到小依次为：猪、鸡、绵羊、绒山羊、牛。绒山羊和绵羊的谷氨酸、天冬氨酸、甘氨酸和丙氨酸含量较高,提示鲜味氨基酸含量较高可能是羊肉味鲜美的主要原因。聚类分析结果显示19个绒山羊肌肉样品中的17个与所有绵羊、牛及鸡聚在一起,牛、绵羊与猪完全分开,提示反刍动物和单胃动物体内与鲜味相关的氨基酸模式存在差异。本研究为揭示反刍家畜骨骼肌蛋白特性提供了重要试验依据,并对将来深入揭示绒山羊肉质特性形成的机理提供一定的理论依据。  相似文献   

17.
为了确定秃疮花水溶性制剂的临床应用剂量,用甘肃省畜牧兽医研究所研制的秃疮花水溶性制剂,以局部毒性法、Reed-Muensch法和寇氏Karber法,进行了动物皮肤刺激试验和犊牛睾丸细胞、鸡胚及小鼠的半数致死量( LD50)试验.试验表明,秃疮花水溶性制剂对动物皮肤无刺激;对犊牛睾丸细胞、鸡胚和小鼠的LD50分别为0.4...  相似文献   

18.
鸡传染性支气管炎病毒CQ/01/2004株的分离与鉴定   总被引：2，自引：0，他引：2  
2004年从重庆某肉用鸡场疑似鸡传染性支气管炎的病鸡中采集病料，按常规处理后接种9～10日龄鸡胚，通过鸡胚连续传代培养3代，并对该分离毒株的鸡胚致病性、血凝性和NDV的干扰特性进行检测．同时进行了动物回归试验。结果表明，该分离株具有IBV感染特征，可使鸡胚胚体出血、蜷缩、矮化；该分离毒株无直接血凝性，对NDV有明显的干扰作用；动物回归试验中有75％的感染鸡在10d内发病或死亡。剖检病死鸡可见肾苍白、肿胀，肾小管内充塞大量尿酸盐，支气管有出血点、有大量粘液。采用反转录．聚合酶链式反应（RT-PCR）技术对CQ／01／2004的纤突蛋白S1基因进行扩增、克隆和序列测定，结果表明该基因具有IBVSl基因的共有分子特征，将测序结果提交GenBank进行同源性检索，发现分离株CQ／01／2004和J株S1的同源性最高，核苷酸同源性为94％，氨基酸同源性为89．4％，与M41的核苷酸同源性为80．6％，氨基酸同源性为78．0％。试验结果表明，分离的病毒株CQ／01／2004为鸡传染性支气管炎病毒。  相似文献   

19.
试验旨在探讨在饲粮不同非纤维性碳水化合物/中性洗涤纤维条件下,奶山羊发生亚急性瘤胃酸中毒（subacute rumen acidosis,SARA）过程中瘤胃溶纤维丁酸弧菌、牛链球菌及埃氏巨型球菌数量的变化。选用6只安装有永久性瘤胃瘘管的泌乳期关中奶山羊为试验动物,采用动物自身前后对照法,试验分4期进行,每期10d,依次饲喂NFC/NDF比分别为1.02（Ⅰ期）、1.24（Ⅱ期）、1.63（Ⅲ期）、2.58（Ⅳ期）的4种饲粮,以逐渐增加饲粮精料含量的方式诱导奶山羊发生SARA,并采用实时定量PCR技术对瘤胃内溶纤维丁酸弧菌、牛链球菌及埃氏巨型球菌的数量变化进行定量分析。结果表明：①随着饲粮NFC/NDF比的逐步升高,溶纤维丁酸弧菌和埃氏巨型球菌的数量均增加,但当饲粮NFC/NDF比升至2.58时,与其他试验期相比,埃氏巨型球菌的数量极显著增加（P〈0.01）,而溶纤维丁酸弧菌的数量却极显著降低（P〈0.01）;②牛链球菌的数量随着饲粮NFC/NDF比的逐步增加呈显著下降趋势（P〈0.05）,但到第Ⅳ期又恢复到第Ⅰ期的数量。结果提示,当奶山羊发生SARA时,瘤胃牛链球菌的数量无明显变化,对低pH值敏感的溶纤维丁酸弧菌数量急剧下降,而耐酸性的埃氏巨型球菌数量表现为大幅增加。  相似文献   

20.
The interaction between Newcastle disease virus (NDV) and Escherichia coli endotoxin was studied in cell cultures, embryonated chicken eggs, and 8-wk-old chickens. These interactions were evaluated according to the induction of specific or nonspecific resistance in the host system and the virus titer produced in both chicken embryos and chickens. The endotoxin of E. coli induced a decrease in the size of the bursa of Fabricius in live chickens. Escherichia coli endotoxin given intravenously induced plasma antiviral activity in chickens that was interpreted to be interferon, as detected in a vesicular stomatitis virus plaque reduction assay. Endotoxin failed to produced toxic effects in the chicken embryo fibroblasts (CEFs) or to result in any antiviral effect because no change was noted in the number of NDV plaques formed in CEF cultures. When endotoxin was given 3 days before NDV exposure in chickens, the virus titers were significantly (P < 0.05) decreased from a peak of 10(2) to 10(0.18), 10(2.5) to 10(0.18), and 10(2.5) to 0 in the spleens, lungs, and kidneys, respectively, at 72 hr post-NDV inoculation. When endotoxin was given 24 hr after NDV inoculation, the NDV titer significantly (P < 0.05) increased from 10(2.0) to 10(3.5), 10(2.5) to 10(6.5), 10(2.5) to 10(4.5), 0 to 10(2.5) in the spleen, lungs, kidneys, and liver, respectively, at 72 hr after NDV inoculation. In chicken sera, hemagglutination inhibition (HI) titer to NDV was significantly (P < 0.05) enhanced from 1164 to 3127 when endotoxin was given prior to virus inoculation. However, there was a decrease in HI to NDV from 1164 to 727 without a significant difference in chicken sera when NDV was given prior to endotoxin inoculation.  相似文献   

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