• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >ASSOCIATION OF FOOT-AND-MOUTH DISEASE VIRUS WITH BOVINE MILK CONSTITUENTS.
【24h】

ASSOCIATION OF FOOT-AND-MOUTH DISEASE VIRUS WITH BOVINE MILK CONSTITUENTS.

机译：牛乳成分与口蹄疫病毒的关联。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The milk secretory process of mammary gland epithelial cells of cows naturally infected with foot-and-mouth disease (FMD) was examined for synthetic events which may play a role in acquired virus stability.;The virus survived in milk and milk components after high temperature-short time (HTST) pasteurization (a minimum temperature of 71.7C for at least 15 sec). Skim milk casein and the milk fat globules (MFG) of cream were considered candidates for conferring insulative protection against thermal and pH inactivation of FMD virus in milk. Treatment of skim milk with sequestering agents EDTA and EGTA resulted in partial dissolution of casein, but was without effect on virus titer. However, treatment of skim milk with sodium dodecyl sulfate (SDS), a protein denaturant, increased the infectivity titer by 0.8 to 1.0 log(,10).;Fractionation of skim milk on a ficoll sucrose gradient produced a non-infectious visible band which contained vesicle-like structures when examined by electron microscopy (EM).;The infectivity titer of the buttermilk fraction of butter was 1.0 to 1.5 log(,10) pfu/ml higher than that of the original cream sample. The membranous nature of this fraction was confirmed by EM observation of membranous strands of varying lengths containing adsorbed virus-like particles. The pelleted aqueous fraction contained 0.007% of the original infectivity of the cream sample. The butter and butter-oil fractions contained intermediate concentrations of infectivity.;A natural route of infection was achieved by contact exposure of susceptible cattle to FMD-infected donor animals. The onset of infection, as determined by the observation of clinical signs of FMD or the initial detection of a virolactia (presence of virus in milk) varied in occurrence with each cow. The virus was recovered from milk and components: skim milk, cream and reconstituted pelleted debris, for periods up to 9 days after the onset of virolactia. Virolactias were detected before, during and after the appearance of clinical signs of FMD. Infectivity titers were slightly higher in cream than in the skim milk component.;Milk from cows before infection contained multi-sized milk fat globules (0.1 to 1% containing cytoplasmic fragments (signets)), anucleated membrane limited vesicle-like structures and a few lymphocyte and basophiles. After the appearance of clinical signs of FMD, the concentration of white blood cells, cellular fragments, debris and on occasion gram positive cocci in the milk, increased significantly.;The hematogenous spread of FMD virus in cattle infected by contact exposure was evidenced by histopathological changes in mammary gland secretory epithelial cells in hematoxylin and eosin (H&E) preparations, as well as by immunofluorescent and Protein-A horseradish peroxidase (PrAPo) labeling of FMD viral antigens.;The synthesis and release of casein and milk fat globules by FMD-infected cells was demonstrated by the respective labeling or staining of these constituents with anti-casein gammaglobulin-PrAPo or oil Red O.;Based upon EM examination, at least four mechanisms for viral exocytosis from infected cells exist: (1) release contained in membrane limited vesicles; (2) release associated with lipid droplet within MFG membrane; (3) merocrinal release associated with casein into the lumen and (4) release through lysis of the infected cell.;The association of FMD virus with milk components was observed throughout the course of infection and has the potential to enhance the stability of FMD virus in milk. The internal entrapment of virus particles by milk components in FMD infected cells would provide an adequate protective environment against thermal and pH inactivation.
机译：检查了自然感染口蹄疫（FMD）的奶牛的乳腺上皮细胞的乳汁分泌过程中可能影响获得性病毒稳定性的合成事件;该病毒在高温后可在乳汁和乳汁成分中存活-短时（HTST）巴氏灭菌（最低温度71.7C至少15秒）。脱脂酪蛋白和乳脂的乳脂球（MFG）被认为可以提供绝缘保护，以防止牛奶中FMD病毒的热和pH失活。用螯合剂EDTA和EGTA处理脱脂牛奶可导致酪蛋白部分溶解，但对病毒滴度无影响。但是，用蛋白质变性剂十二烷基硫酸钠（SDS）处理脱脂牛奶会使感染力滴度增加0.8至1.0 log（，10）。;在ficoll蔗糖梯度上分馏脱脂牛奶会产生非感染性可见带，当通过电子显微镜（EM）检查时，其含有囊状结构。黄油的酪乳级分的感染性滴度比原始奶油样品高1.0至1.5 log（，10）pfu / ml。通过EM观察含有吸附的病毒样颗粒的不同长度的膜链的EM观察证实了该级分的膜性质。沉淀的含水部分含有乳膏样品原始感染性的0.007％。黄油和黄油油馏分包含中等浓度的传染性。通过将易感牛与FMD感染的供体动物接触，可以实现自然的感染途径。通过观察口蹄疫的临床体征或初步检测出病毒感染（牛奶中存在病毒）来确定感染的发作，每头牛的发生情况各不相同。病毒从乳汁和内在成分中回收：脱脂乳，稀奶油和重构的颗粒状沉淀物，在发生内分泌性感染后长达9天。在口蹄疫的临床体征出现之前，期间和之后都检测到了弧菌。乳脂中的传染性滴度略高于脱脂乳成分。；感染前来自奶牛的乳中含有多种大小的乳脂小球（0.1％至1％的细胞质碎片（标记）），无核膜限制的囊状结构和一些淋巴细胞和嗜碱性粒细胞。在出现口蹄疫的临床症状后，牛奶中白细胞，细胞碎片，碎片的含量以及偶尔出现的革兰氏阳性球菌的浓度显着增加。组织病理学证实口蹄疫病毒在接触接触感染的牛中的血源性扩散。苏木精和曙红（H＆E）制剂中乳腺分泌上皮细胞的变化，以及FMD病毒抗原的免疫荧光和蛋白A辣根过氧化物酶（PrAPo）标记。； FMD-通过用抗酪蛋白球蛋白-PrAPo或油红O对这些成分进行相应的标记或染色来证明感染的细胞;基于EM检查，存在至少四种导致感染细胞发生病毒胞吐的机制：（1）膜中释放有限的囊泡; （2）释放与MFG膜内的脂质滴有关的释放； （3）与酪蛋白相关的黑色素释放进入管腔，以及（4）通过裂解被感染细胞而释放。;在整个感染过程中均观察到口蹄疫病毒与乳成分的关联，并有可能增强口蹄疫病毒的稳定性在牛奶中。被FMD感染的细胞中的牛奶成分将病毒颗粒内部截留，将为热和pH失活提供足够的保护环境。

著录项

  • 作者

    BLACKWELL, JOHN HENRY.;

  • 作者单位

    Cornell University.;

  • 授予单位 Cornell University.;
  • 学科 Food science.
  • 学位 Ph.D.
  • 年度 1981
  • 页码 147 p.
  • 总页数 147
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号