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1.
为研究丝氨酸蛋白酶HtrA对鸡白痢沙门菌在巨噬细胞内生存的影响,本研究利用λ-Red同源重组系统构建了鸡白痢沙门菌(ATCC19945) htra基因缺失突变株(ATCC19945Δhtra),通过测定其巨噬细胞内存活能力、应激条件实验,探究Htr A蛋白在鸡白痢沙门菌致病过程中的作用。结果显示,缺失株ATCC19945Δhtra与野生型菌株和回复菌株相比,其生长速度、生化特性无明显差异,但其巨噬细胞内存活能力显著降低。应激环境试验结果表明,htra基因缺失后鸡白痢沙门菌对pH、热和H_2O_2氧化应激的敏感性增加,在蛋清中生存能力下降,生物被膜形成能力显著下降。本研究为进一步阐释鸡白痢沙门菌的胞内存活机制、疫苗开发奠定基础。 相似文献
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《中国预防兽医学报》2018,(11)
为研究鸡白痢沙门菌双组份系统CpxR/A的作用,本研究利用λ-Red重组技术构建了鸡白痢沙门菌cpxR基因缺失突变株ATCC19945ΔcpxR,通过应激试验和细胞感染试验,揭示cpxR基因在鸡白痢沙门菌致病机制中的重要作用。实验结果表明,cpxR基因缺失并未影响细菌的生长速度、生化特性和在鼠源巨噬细胞Raw264.7中的存活能力,但使得细菌对热、酸、碱和氧化应激的敏感性增加,同时在蛋清中的生存能力下降。本研究为进一步阐释CpxR/A系统的重要功能奠定基础。 相似文献
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《中国预防兽医学报》2020,(6)
wzx/wzy是调控革兰氏阴性菌O抗原合成的主要途径,对细菌的生存、代谢乃至致病性均具有重要作用。为研究该基因簇中wzxE基因对鸡白痢沙门氏菌致病性的影响,本研究通过同源重组方法构建了鸡白痢沙门氏菌参考菌株ATCC19945的wzxE基因缺失菌株(ATCC19945 ΔwzxE),通过生长特性试验、应激试验、细菌蛋清存活能力测定、1日龄雏鸡感染试验对比基因缺失突变株与野生菌株、回补株的生物学特性及分析WzxE蛋白功能。结果显示,wzxE基因缺失并未影响白痢沙门菌的生长特性。应激试验显示,wzxE基因缺失会导致鸡白痢沙门菌在酸性和H_2O_2处理条件下生存能力的显著下降,回补之后得到明显回复。细菌蛋清存活能力检测结果显示,wzxE基因缺失株较野毒株在蛋清内的存活能力下降明显,回补之后存活能力显著增强。1日龄雏鸡感染试验结果显示,鸡白痢沙门菌ATCC19945野生菌株、wzxE基因缺失株和回补株对雏鸡的半数致死量分别为1. 65×10~8cfu、4. 67×10~8cfu和3. 43×10~8cfu,毒力下降不明显。提取鸡白痢沙门菌参考株和缺失株LPS,经SDS-PAGE后银染检测显示,wzxE缺失不影响鸡白痢沙门菌LPS总体成分构成,但影响特定LPS特定寡糖单位的含量。本研究为进一步阐释鸡白痢沙门氏菌细菌毒力的影响因素、疫苗开发奠定基础。 相似文献
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《中国家禽》2016,(16)
为进一步探讨沙门菌的致病机制,研究构建了耶尔森强毒力岛(HPI)基因缺失沙门菌,并检测了HPI基因缺失沙门菌对鸡巨噬细胞吞噬能力的影响。应用PCR扩增沙门菌HPI同源的cat基因片段,借助p KD46质粒在HPI阳性沙门菌中表达Exo、Beta和Gam 3种蛋白质,实现HPI全岛敲除。利用HPI基因敲除体系建立沙门菌感染巨噬细胞模型,并检测其对巨噬细胞吞噬能力的影响。结果显示,同源重组测序为阳性;irp2、irp9及irp5 PCR鉴定为阴性;HPI阳性沙门菌感染鸡巨噬细胞(M-HPI)后0~2 h,其对刚果红染色酵母的吞噬能力显著低于HPI缺失沙门菌(M-△HPI)(P0.05),而2 h以后尽管仍然保持以上变化,但未见统计学意义(P0.05)。研究成功建立了沙门菌HPI全基因敲除方法和沙门菌HPI基因缺失株,HPI基因缺失株沙门菌感染可损伤鸡巨噬细胞的吞噬能力。 相似文献
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采用Real-time PCR的方法检测了AA肉鸡感染沙门菌后6h和1、2、3、5、7d的胸腺、脾、法氏囊和小肠中Nod1基因的表达量,分析Nod1基因在沙门菌感染过程中的表达量变化情况,在转录水平探讨沙门菌感染对Nod1基因表达量的影响。试验分为3组,鸡白痢沙门菌组,肠炎沙门菌组和对照组。结果显示,感染组与对照组相比,在4个器官中Nod1基因的表达量在2种沙门菌感染后的一定时间内均出现了上升,表达量达到高峰的时间分别为2d(胸腺)、5d(脾脏)、2d和3d(法氏囊)及5d和7d(小肠)。结果表明,2种沙门菌感染均可激活Nod1基因表达,提示Nod1基因可能与鸡的抗感染免疫作用有关。 相似文献
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旨在探究鸡白痢沙门菌(Salmonella enterica serovar Pullorum,S.Pullorum)感染雏鸡后骨髓miRNA的差异表达特征,为深入了解鸡白痢沙门菌的致病机制提供理论基础。将7日龄SPF雏鸡随机分为两组,分别口服鸡白痢沙门菌和PBS,于感染24 h后采集骨髓进行miRNA测序,筛选差异倍数≥2且P值≤0.05的差异表达miRNAs进行靶基因预测以及GO、KEGG富集分析,随机选取6个miRNAs进行qRT-PCR验证,构建与免疫过程相关的miRNA-mRNA靶点网络。通过miRNA测序,共获得20个已知的差异表达miRNAs,其中11个上调,9个下调。qRT-PCR结果表明,miRNA变化趋势与测序结果一致。GO分析结果表明,差异表达基因主要富集在膜运输、信号转导、免疫系统、碳水化合物代谢、糖类的生物合成和代谢等,KEGG的信号通路主要富集在Notch信号通路、Hedgehog信号通路、PPAR信号通路、AMPK信号通路、Hippo信号通路等,miRNA-mRNA网络互作发现,gga-miR-1466和gga-miR-6643-5p可能是参与免疫过程相关的关键miRNA。本研究解析了鸡白痢沙门菌感染雏鸡的骨髓miRNA表达谱特征,为了解鸡白痢沙门菌和鸡之间相互作用的复杂分子致病机制提供了新的见解,为防控鸡白痢沙门菌感染提供了新策略。 相似文献
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本文旨在研究中国华东地区沙门菌分布情况及其优势菌的血清型变异情况.收集2010年10月-2012年8月来源于江苏、安徽、上海等地区的1 730份禽源样品,进行增菌、纯化、PCR鉴定、血清学试验及生化试验,并对7株血清型有变异的疑似鸡白痢沙门菌进行进一步序列测定,对血清型进行分析.结果表明,本次调查中共分离沙门菌87株,包括鼠伤寒沙门菌、德尔卑沙门菌、圣保罗沙门菌、鸡白痢沙门菌及阿巴特图巴沙门菌,并且在鸡白痢沙门菌血清型H相存在Hd、Hg阳性的现象.结果提示,中国禽类沙门菌感染以鸡白痢沙门菌感染为主,且存在血清型变异情况,变异概率呈上升趋势. 相似文献
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《动物医学进展》2016,(2)
为了研究鸡白痢沙门菌SpiC蛋白的功能,以鸡白痢沙门菌S06004基因组DNA为模板PCR扩增spiC基因,进行克隆测序和生物信息学分析,并调查该基因在255株不同年代鸡白痢沙门菌分离株中的分布与进化情况。结果显示,鸡白痢沙门菌spiC基因全长384bp,编码127个氨基酸,在不同年代分离株中稳定存在。推导SpiC蛋白无跨膜区、信号肽和卷曲螺旋结构,有1处酪蛋白激酶Ⅱ磷酸化位点,2处N-豆蔻酰化位点,预测线性抗原表位主要分布在15-20、29-35、52-53、70-72、83-85、89-94aa。利用SWISS MODEL在线程序建模,得到SpiC三维结构模型。同源性及进化分析显示spiC基因仅存在于沙门菌中且比较保守,鸡白痢沙门菌SpiC蛋白与沙门菌肠道亚种亲缘关系最近。 相似文献
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最近的研究表明，补加氨基酸可减少奶牛日粮中过瘤胃蛋白质（ＵＤＰ）的供应量，同时提高总产奶量和乳蛋白含量。 在泌乳前期，奶牛的干物质采食量较低，而泌乳量较高。这就需要在日粮中有足够的可利用能量和蛋白质。现在瘤胃保护脂肪或过瘤胃脂肪被用来补充以谷类为基础的传统精料，为高产奶牛提供了可通过瘤胃的足够能量。相类似地提供足够的瘤胃微生物蛋白质，以便提供足够的氨基酸，从而使高产奶牛获得最大产奶量和乳蛋白。２０世纪９０年代早期，人们就发现蛋氨酸和赖氨酸是合成奶蛋白的限制性氨基酸，在此基础上奶牛营养学家借助计算… 相似文献
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The possibilities and economic benefits of controlling mycoplasmal pneumonia of pigs caused by Mycoplasma hyopneumoniae by immunisation with Respisure and by Tiamutin treatment were studied. The experiment was carried out in a herd comprising 1000 sows which was free of PRRS, Aujeszky's disease, swine dysentery and leptospirosis, and the prevalence of mycoplasmal pneumonia was low because the farm had recently been restocked. Groups C1 and C2 served as untreated controls, while Groups R1 and R2 received a prestarter diet containing 100 ppm Tiamutin from the time of weaning. Piglets of Group R1 were vaccinated with Respisure vaccine once on day 69, while those of Group R2 twice, on days 65 and 80. Piglets of Groups ST1 and ST2 were fed 100 ppm Tiamutin in the diet for 7 days at the time of weaning and then at 4 months of age, while pigs of Group ST2 received such treatment also in the 6th month of life. The efficacy of treatment was analysed on the basis of the number of animals that died, were emergency slaughtered or were retarded in growth in the different groups, the body weight of animals at weaning, at 94 and 148 days of age and at the time of slaughter, their daily body weight gain, the lung lesions found in animals slaughtered from the different groups, the costs of medication and vaccination, and the cost-benefit calculations of the results. The mortality and emergency slaughter rate was 2.88% and 4.62% in Groups ST2 and ST1, respectively, 4.23% and 4.62% in Groups R2 and R1, respectively, and 8.39% and 9.44% in the control groups (C2 and C1, respectively). The rate of growth retardation was 0.48% and 2.12% in Groups R1 and R2, respectively, 1.59% and 3.46% in Groups ST1 and ST2, respectively, as compared to 8.03% and 6.55% in the control groups (C1 and C2, respectively). The severity score of lung lesions was 1.82 and 1.46 in Groups R1 and R2, 2.18 and 2.93 in Groups ST1 and ST2, and 3.83 and 4.02 in the control groups C1 and C2, respectively. The mean finishing weight of pigs was 102.4-107.8 kg and 95.2-106.6 kg in the treated groups and 94.5-98.6 kg in the control groups. The classification of pigs according to the EUROP categories showed a shift to the E and U categories in the treated groups. The average feed cost per one kg of liveweight was 77.89-82.64 Forints in the treated groups and 85.66 Forints in the control groups. 相似文献
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Immature Fasciola hepatica release a papain or cathepsin B-like proteolytic enzyme which cleaves immunoglobulins (Ig) of mouse, rat, rabbit and sheep in vitro. Mouse IgG and IgM molecules are both susceptible to cleavage as is hemoglobin. Whether single or multiple proteases are responsible for Ig cleavage is unknown. The proteolytic activity of secreted enzyme(s) is optimal at pH 3.5-4.5, but activity is also present at pH 7. Proteolysis is enhanced in the presence of 5 mM dithiothreitol or 100 mM cysteine. Based on studies with protease inhibitors, the F. hepatica enzyme activity has been identified as a thiol protease. It is destroyed by heating at 56 degrees C for 1 h, but retains activity after storage at -20 degrees C for 7 days. Whether inhibition of the proteolytic activity increases the susceptibility of F. hepatica immature worm to any extant immune effector mechanisms in hosts remains to be determined. 相似文献
14.
蛋白质过瘤胃保护途径 总被引：4，自引：0，他引：4
反刍动物优质蛋白质饲料 (豆饼、豆粕等 )的过瘤胃保护技术的研究 ,是目前蛋白质营养研究的热点。通过各种保护技术可使优质蛋白质通过瘤胃时的降解率下降 ,使小肠消化吸收的必需氨基酸量增加。本文对目前蛋白质的各种过瘤胃保护途径和效果进行了综述。1 物理方法1 1 加热处理 包括干热、焙炒、热压、蒸汽加热及加热与其他物理化学方法复合处理等。加热可导致蛋白质变性 ,使疏水基团更多地暴露于蛋白质分子表面 ,使蛋白质溶解度降低 ,从而降低蛋白质在瘤胃中的降解率。Ｍｉｅｌｋｅ等 (1 979)用热处理的豆饼饲喂奶牛 ,泌乳早期产奶量由 … 相似文献
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H Murata 《The British veterinary journal》1989,145(3):257-262
The effect of sera from 4-h road-transported calves on mitogen-induced blastogenesis of bovine lymphocytes was investigated. Sera collected just after transportation showed a significant suppression (P less than 0.05) on blastogenesis. The immunosuppressive activity was reduced from those sera when they were treated with dextran-coated charcoal. Fractionation of the sera by ultrafiltration revealed that the activity was mainly concentrated in the fractions of molecular weights less than 50 kD. 相似文献
16.
J. T. Warren I. Mysterud O. M. Stensli M. Berg E. Movik 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(3):190-192
The effect of straw bedding on aggression, production and welfare in loose-housed, pregnant sows was studied in 14 commercial farms, half of them with straw bedding and the other half with a concrete floor. The herds were visited twice and agonistic behaviour was observed. Body lesions, movement disorders and production results were also recorded. There were no significant differences in aggression, body lesions or production results between herds with concrete floor and herds with straw bedding. Movement disorders were more common in herds with concrete floor than in herds with straw bedding. Herds with a high score for movement disorders tended to have a higher percentage of sows returning to oestrus than herds with a low score. Individual data showed no significant correlation between production variables and body lesion score. However, the sows that were culled had a higher mean score for body lesions than the means of both types of farms. Altogether, this study shows that straw bedding was advantageous in preventing leg problems, but the presence of straw did not affect the aggression among sows, the incidence of body lesions or the production results. 相似文献
17.
K S Latimer A V Jain H B Inglesby W D Clarkson G B Johnson 《Journal of the American Veterinary Medical Association》1989,195(1):77-80
A 4-month-old Pomeranian pup was examined because of anorexia, salivation, and persistent vomiting. Initial laboratory testing revealed marked hemolytic anemia with spherocytosis. Survey abdominal radiography revealed 4 metal objects which, when removed by gastrotomy, were identified as pennies. Of 4 pennies, 3 were minted since 1983 and were heavily pitted over the surface and rim. Partially digested pennies were composed of a copper-plated high zinc concentration alloy. Further laboratory testing indicated a marked increase in serum zinc concentration in the pup (28.8 mg/L), confirming metal toxicosis. Serum zinc concentrations decreased during recovery. 相似文献
18.
The procedures of manual and machine catching acted as short-term stressors, and induced a state of fear in 8-week-old broiler chickens. The heart rate of birds caught by both methods rose to similar high values but that of birds caught by machine returned to near normal rates more quickly, suggesting that they were less stressed. The duration of tonic immobility, a response which increases with fearfulness, was much longer in manually-caught birds. These results suggest that stress could be reduced and welfare improved by catching and picking up broiler chickens by a carefully designed machine, rather than by hand. 相似文献
19.
Maehara S Osawa A Itoh N Wakaiki S Tsuzuki K Seno T Kushiro T Yamashita K Izumisawa Y Kotani T 《Veterinary ophthalmology》2005,8(6):407-413
It is difficult to detect discrete cone function with the present conventional electroretinography (ERG) examination. In this study, we developed contact electrodes with a built-in color (red (644 nm), green (525 nm), or blue (470 nm)) light source (color LED-electrode), and evaluated an experimental model of digoxin in the dog. First, 17 normal Beagle dogs were used to determine which electrode works well for color ERG measurement on dogs. Then, color ERG was performed on seven normal Beagle dogs at various points during a 14-day period of digoxin administration. A single daily dose of 0.0125 mg/kg/day, which is within the recommended oral maintenance dosage range for dogs, was administered orally for 2 weeks. Ophthalmic examination, measurement of plasma concentration of digoxin, and color ERG examination were performed. On first examination, amplitudes of all responses were significantly (P < 0.01) lower with the red, than with the blue and green electrodes during ERG recording. In ERG using the red electrode, the standard deviation was large. According to these preliminary results, the red electrode was not used in the experimental dog model with digoxin. In the digoxin administrated animals, no significant change was observed in the ophthalmic examination findings. The digoxin level increased steadily throughout the dosing period but was always within the therapeutic range for dogs. In rod ERG, no abnormalities were detected with any electrode. In standard combined ERG, decreased amplitude of the a-wave was detected with every electrode. In single flash cone ERG, prolongation of implicit time was detected by color ERG with the blue and green electrodes. In 30-Hz flicker ERG, decreased amplitude was detected only by color ERG with the blue electrode. The decreased amplitude and prolonged implicit time recovered after termination of digoxin administration. Cone dysfunction induced by digoxin in the dog was revealed by multicolor ERG using blue and green LED-electrodes. Multi-color ERG was useful for detecting cone type-specific dysfunction in the dog. 相似文献
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加强通风和喷雾降温对奶牛生产性能的影响 总被引：4，自引：0，他引：4
黑白花奶牛是耐寒怕热的家畜，适宜温度范围44～211℃，产奶最适宜温度10℃，当环境温度自21℃升高至35℃，产奶量将大幅下降，乳的组成亦发生变化。合肥地区属于亚热带季风气候，夏季温度高达35℃以上，极端最高温度达40℃，奶牛长时期处于这种环境中，高温引起热应激反应，散热困难，体温升高，采食量减少，增加散热的能量消耗和体蛋白质的分解，造成内分泌活动和酸碱平衡失调乃至死亡。为降低热应激对奶牛生产的影响，我场在夏季采用强制通风和喷雾的措施，可提高奶牛单产达20％的显著效果。1 材料与方法11 喷雾设备111 加压泵… 相似文献