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1.
Inoculation of tracheal organ cultures from bovine foetuses with Mycoplasma bovis resulted in a loss of cellular structure of the lamina propria, followed 20-22 days later by lifting and detachment of overlying epithelium. The effect was associated with large numbers of M. bovis, identified by immunoperoxidase labelling and electromicroscopy, infiltrating between the epithelial cells and amassing in the lamina propria, especially in the region of the basement membrane of the epithelium. Ciliary activity was undiminished for up to 18 days following inoculation and little or no cytopathic effect on the ciliated epithelium was seen in spite of the close proximity of large numbers of organisms. In contrast, M. dispar was restricted to the margin of the ciliated epithelium where, as previously reported, it caused pyknosis, sloughing and flattening of the epithelium with consequent loss of ciliary activity. The cytopathology observed for each mycoplasma bore a close similarity to the behaviour of the two mycoplasmas in vivo and it is suggested that the organ culture system may be a useful and relevant system to elucidate the pathogenic mechanisms for each mycoplasma. 相似文献
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Van Deun K Pasmans F Ducatelle R Flahou B Vissenberg K Martel A Van den Broeck W Van Immerseel F Haesebrouck F 《Veterinary microbiology》2008,130(3-4):285-297
Although poultry meat is now recognized as the main source of Campylobacter jejuni gastroenteritis, little is known about the strategy used by the bacterium to colonize the chicken intestinal tract. In this study, the mechanism of C. jejuni colonization in chickens was studied using four human and four poultry isolates of C. jejuni. The C. jejuni strains were able to invade chicken primary cecal epithelial crypt cells in a predominantly microtubule-dependent way (five out of eight strains). Invasion of cecal epithelial cells was not accompanied by necrosis or apoptosis in the cell cultures, nor by intestinal inflammation in a cecal loop model. C. jejuni from human origin displayed a similar invasive profile compared to the poultry isolates. Invasiveness of the strains in vitro correlated with the magnitude of spleen colonization in C. jejuni inoculated chicks. The C. jejuni bacteria that invaded the epithelial cells were not able to proliferate intracellularly, but quickly evaded from the cells. In contrast, the C. jejuni strains were capable of replication in chicken intestinal mucus. These findings suggest a novel colonization mechanism by escaping rapid mucosal clearance through short-term epithelial invasion and evasion, combined with fast replication in the mucus. 相似文献
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为了研究贝氏莫尼茨绦虫自然感染绵羊对小肠黏膜免疫组织的影响,分别从宏观、微观及亚微观水平对自然感染贝氏莫尼茨绦虫的成年绵羊(感染组)肠道进行了细致地观察,并与正常成年绵羊(正常组)进行了比较.结果显示,感染组肠道所见虫体平均长度为1.5m,头节主要吸附在空肠淋巴集结分布丰富的部位,一般寄生数量为1～2条.眼观,虫体寄生部位黏膜增厚,表面有大量灰白色黏液附着,其间可见点状出血.镜下,局部黏膜上皮脱落,而在完整的黏膜上皮处,其上皮细胞、上皮内淋巴细胞、杯状细胞的数量都明显增多;固有层内毛细血管充血,淋巴细胞、浆细胞、弥散淋巴组织以及肠腺杯状细胞均有不同程度的增生,头节寄生处部分肠腺坏死;黏膜下层淋巴小结、淋巴集结显著增生,部分增生凸入固有层形成新的圆顶区;固有层与黏膜下层以及黏膜肌层可见大量嗜酸性粒细胞浸润.扫描电镜下,感染组肠黏膜上皮脱落;贝氏莫尼茨绦虫头节呈椭球状,有4个吸盘,无顶突,小沟,表面覆盖一层致密的微绒毛.研究结果表明,肠黏膜增厚,主要是局部黏膜免疫相关细胞在寄生虫虫体表面覆盖的微绒毛的不断刺激下,机体抗感染自身组织增生所致.成年绵羊对抗贝氏莫尼茨绦虫的感染可能是通过黏膜免疫相关组织增生来加强局部免疫力而实现的. 相似文献
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Adherence of Moraxella bovis to cell cultures of bovine origin 总被引：5，自引：0，他引：5
The adherence of five strains of Moraxella bovis to cell cultures was investigated. M bovis adhered to cultures of bovine corneal epithelial and Madin-Darby bovine kidney cells but not to cell types of non-bovine origin. Both piliated and unpiliated strains adhered but piliated strains adhered to a greater extent than unpiliated strains. Antiserum against pili of one strain inhibited adherence of piliated strains but caused only slight inhibition of adherence to the unpiliated strains. Treatment of bacteria with magnesium chloride caused detachment of pili from the bacterial cell and markedly inhibited adherence of piliated strains but caused only slight inhibition of adherence by the unpiliated strains. The results suggested that adhesion of piliated strains to cell cultures was mediated via pili but that adhesins other than pili may be involved in the attachment of unpiliated strains of M bovis to cells. 相似文献
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Evidence for the Colonization of Lactic Acid Bacteria in the Gastrointestinal Tract of Suckling Mink
Lactic acid bacteria are considered indigenous members of the gastrointestinal microflora in a number of animal species (Savage 1977a). Some intestinal strains of lactobacilli and streptococci are aWe to adhere to stratified squamous epithelium of some animals (Tannock et al. 1987), in the non-secreting part of the stomach of piglets (Barrow et al. 1980, Fuller et al. 1978) and rodents (Tannock et al. 1982), and in the crop of poultry (Fuller 1978). The presence of lactic acid bacteria in the digestive tract is believed to be of beneficial value to the host animal (Fuller 1989). The production of organic acids in the stomach or the crop helps maintaining a low pH which may be important for inhibiting the colonization of potentially pathogenic bacteria, particularly in the newborn animal (Barrow et al 1980, Fuller 1977, Fuller 1978). The adhesion of lactobacilli to squamous epithelium is host specific: strains capable of adhering to the epithelium of piglets are usually not able to adhere in rodents or poultry and vice versa (Fuller 1978, Lin & Savage 1984, Tannock et al 1982). Adhesion of lactic acid bacterial strains to other epithelia than stratified squamous epithelium has been reported. Thus, the attachment of lactobacilli to cells from the secreting epithelium of the murine stomach (Kotarski & Savage 1979), to intestinal cells of humans (Goldin & Gorbach 1987), and to columnar epithelial cells of piglets and calves (Mäyrä-Mäkinen et al 1983) has been demonstrated using in vitro methods. In another study the in vivo attachment of Enterococcus faecium to duodenal epithelium of gnotobi-otic chickens was demonstrated (Fuller et al 1981). Recent research indicated that in adult mink lactic acid bacteria are not indigenous members of the intestinal flora, and they do not attach to epithelium in any part of the gastrointestinal tract (Federsen & Jørgensen 1992). The present paper presents evidence that Gram positive cocci may colonize the gut of suckling mink kits and attach to the gut mucosa. 相似文献
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Effects of Escherichia coli heat-stable enterotoxin b on small intestinal villi in pigs, rabbits, and lambs 总被引：4，自引：0，他引：4
Culture supernates from two strains of E. coli were placed into different ligated intestinal sections (loops) of each animal. The two bacterial strains were identical except that one contained a plasmid carrying the heat-stable toxin b (STb) gene, while the other did not. Morphometric techniques were used to assess villous epithelial surface areas and mucosal volumes in both intestinal segments exposed to STb-positive (test) and to STb-negative (control) supernates. In pigs whose intestines were exposed to STb-positive supernatants for 2 hours, both villous epithelial surface area and mucosal volume were significantly smaller in test loops than in control loops (P less than 0.02). In test loops of pigs incubated for 1 hour, and in test loops of lambs incubated for 2 hours, there was a decrease in villous epithelial surface area which approached the test for significance but did not meet it (0.05 less than P less than 0.10). Rabbit test loops did not differ from rabbit control loops in either villous epithelial surface area or mucosal volume. Histological examination of the tissues from all three species revealed epithelial changes in porcine and ovine tissues only. In porcine and ovine tissues, epithelium at villous tips was seen to be cuboidal or squamous, or even to be absent. Villi with similarly altered epithelium were seen in control loops, but were seen much more frequently in test loops. These epithelial changes were seen as early as 30 minutes of incubation in pigs. Intestinal tissues from these pigs were examined by transmission electron microscopy, but no difference between test and control tissues was seen.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Jana Kirchhoff Sabine Uhlenbruck Katherina Goris Günther M Keil Georg Herrler 《Veterinary research》2014,45(1):20
Bovine respiratory disease complex (BRDC) is the major cause of serious respiratory tract infections in calves. The disease is multifactorial, with either stress or reduced immunity allowing several pathogens to emerge. We investigated the susceptibility of bovine airway epithelial cells (BAEC) to infection by the three major viruses associated with the BRDC: bovine respiratory syncytial virus (BRSV), bovine herpesvirus type 1 (BHV-1) and bovine parainfluenza virus type 3 (BPIV3). For this purpose, two culture systems for well-differentiated BAEC were used: the air-liquid interface (ALI) system, where filter-grown BAEC differentiate into a pseudostratified respiratory epithelium and precision-cut lung slices (PCLS) where BAEC are maintained in the original tissue organisation. Comparative infection studies demonstrated that entry and release of BPIV3 occurred specifically via the apical membrane with ciliated cells being the major target cells. By contrast, airway epithelial cells were largely resistant to infection by BHV-1. When the epithelial barrier was abolished by opening tight junctions or by injuring the cell monolayer, BHV-1 infected mainly basal cells. Respiratory epithelial cells were also refractory to infection by BRSV. However, this virus infected neither differentiated epithelial cells nor basal cells when the integrity of the epithelial barrier was destroyed. In contrast to cells of the airway epithelium, subepithelial cells were susceptible to infection by BRSV. Altogether, these results indicate that the three viruses of the same disease complex follow different strategies to interact with the airway epithelium. Possible entry mechanisms are discussed. 相似文献
10.
Verna AE Garcia-Pariente C Muñoz M Moreno O García-Marin JF Romano MI Paolicchi F Pérez V 《Zoonoses and public health》2007,54(6-7):243-252
Ruminant infection by Mycobacterium avium subsp. paratuberculosis (MAP) causes a granulomatous inflammatory response in the intestine and associated lymph nodes. Differences either in the affected organs or in the inflammatory infiltrate were observed between species and individuals. Such differences are usually attributed to variations in host immune responses or to inconsistent effects among different MAP strains. To evaluate if different MAP strains induce different immuno-pathological responses in lambs, 28 one-month-old individuals were divided into six groups and inoculated with different MAP strains. Groups 1 and 2 were inoculated with two bovine strains isolated in Argentina that showed different genetic patterns after BstEII-IS900-RFLP (hereafter strains E and A respectively). Group 3 was inoculated with a bovine strain isolated in Spain obtained after a previous step of culture (patterns C1). Group 4 was inoculated with a homogenate of intestinal mucosa of a clinical case affected by the same bovine strain as that of group 3. Group 5 was inoculated with an ovine strain that was directly purified from the intestinal mucosa of a clinical case, and group 6 was kept as control (i.e. no inoculation). Peripheral immune responses were assessed until 150 days post-infection (dpi), when lambs were humanely killed. Pathological studies were performed in tissues from the intestine and lymph nodes. Lesion types and inflammatory infiltrates were examined as indicators of pathogenicity. All the lambs infected with bovine MAP strains showed a common lesion pattern regardless of the strain type. Such pattern was characterized by focal lesions mainly in the mesenteric lymph nodes, the presence of fibrous tissue, and, occasionally, necrosis in the granulomas as well as the presence of numerous giant cells. Differences in lesion severity were observed among groups: lambs from groups 1 and 2 had the highest number of granulomas and the largest lymph node area affected. Lesions in animals from group 5 (infected with an ovine strain) were more severe and occurred mostly in the intestinal lymphoid tissue; necrosis, fibrosis or giant cells were never detected in this group. These results indicate that the MAP strain type induces different pathological responses in lambs. 相似文献
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Adhesion of Staphylococcus aureus and Escherichia coli to bovine udder epithelial cells 总被引：1，自引：0，他引：1
An assay for the adhesion of tritiated thymidine-labelled Staphylococcus aureus and Escherichia coli to bovine mammary ductular epithelial cell lines was developed. The relative adhesion of 15 strains of S. aureus to these cell lines was examined. Four strains did not adhere and the remaining 11 adhered at variable levels. Adhesion to different cell lines was generally similar. Adhesion to freshly collected bovine mammary epithelial cells was significantly greater than that to cells maintained in tissue culture. The system described was demonstrated to be a suitable model for studying adhesion of mastitis-causing organisms to bovine mammary epithelial cells. 相似文献
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益生菌在健康硬骨鱼肠道中不仅起到抑制致病微生物的作用,而且更重要的是,益生菌能够刺激和增强肠道黏膜免疫系统,在肠道免疫中起重要作用。近年来,硬骨鱼黏膜免疫因其多样性及其不明确的定义,已成为热门的研究课题。硬骨鱼与水生环境直接接触,使肠道黏膜表面易受各种病原体的侵袭。免疫调节是硬骨鱼中有效的预防性措施,而益生菌能够提高肠道黏膜表面固有的免疫活性细胞和因子,对病原体起颉颃作用。益生菌主要通过口服方式进入鱼体,而肠道作为其主要靶器官,对鱼体产生特异性免疫应答。因此,关于益生菌影响肠道黏膜免疫系统的研究值得关注。相比于哺乳动物,硬骨鱼具有更加弥散的肠淋巴系统。局部免疫应答所必需的免疫细胞大量存在于肠道黏膜中,并且可以在免疫后的鱼体肠道中监测到局部免疫应答。文章综述了近年来硬骨鱼肠道黏膜免疫系统以及益生菌对硬骨鱼肠道黏膜免疫的影响,并对鱼类益生菌的进一步研究进行了展望,以期为后续研究益生菌与硬骨鱼之间相互作用提供参考。 相似文献
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肠道是肉鸡重要的消化、内分泌及免疫器官，肠道健康主要依赖于营养物质、微生物菌群和肠道黏膜之间的动态平衡。肠道消化吸收功能与肠黏膜上皮细胞的生长及肠道形态结构的完整性直接相关。研究表明，丁酸钠作为能量来源，可刺激肉鸡肠道上皮细胞增殖并改善肠道黏膜形态，促进绒毛生长和肠道组织发育。丁酸钠通过肠道游离脂肪酸受体FFAR2和FFAR3介导肠道内分泌细胞分泌多种激素，促进胃肠黏膜的发育，刺激胃和胰腺分泌消化酶，促进养分消化吸收。丁酸钠是肠道稳态的重要调节因子，可刺激黏蛋白的产生，增加黏液层厚度，降低结肠上皮的通透性，维持肠道完整性和黏膜屏障功能。丁酸钠促进宿主防御肽（HPDs）的合成，抑制肠道内有害菌的增殖，降低内毒素对肠黏膜上皮细胞的损伤。丁酸钠通过抑制NF-κB激酶（IKK）下调促炎症途径，抑制NF-κB的活化，预防肠黏膜炎症发生，进而促进消化吸收和保护肠道健康。综上，丁酸钠具有肠道保护和抗菌作用，可增强肠道完整性，促进营养物质的消化吸收，提高免疫力和抗病力。在饲料工业禁抗的背景下，对抗生素替代品丁酸钠的研究和应用非常重要，作者就丁酸钠对肠道功能的作用机制进行重点阐述，以期为其在肉鸡饲料中替代抗生素提供科学依据。 相似文献
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本研究旨在探究胶质纤维酸性蛋白（glial fibrillary acidic protein,GFAP）在黄羽肉鸡肠道中的分布规律。使用免疫组织化学SABC-AP法,观察鸡肠道中GFAP的分布规律。结果显示,GFAP在鸡小肠黏膜上皮、小肠腺细胞腔面、小肠黏膜下神经丛和肌间神经丛及其血管壁周围均呈强阳性表达,在黏膜固有膜上呈阳性表达;GFAP在鸡大肠黏膜上皮、大肠腺中呈阳性表达,在大肠黏膜下神经丛和肌间神经丛均呈强阳性表达。GFAP是肠神经胶质细胞的特异性标记物之一,观察其在鸡肠道的分布特征有助于阐明肠神经胶质细胞在肠道各段的分布规律,为研究鸡肠神经胶质细胞的功能提供形态学依据。 相似文献
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ZHANG Yu-yu ZHAO Xin-lin QI Feng-hua LU Yan SHI Xiao-yu HAN Xiao-li XU Chun-sheng 《中国畜牧兽医》2017,44(5):1315-1320
The experiment was conducted to explore the distribution of glial fibrillary acidic protein (GFAP) in Yellow feather broiler,and to investigate the morphological characteristics of glial cells of chicken. The distribution of GFAP was studied by immunohistochemistry SABC-AP method. The results showed that GFAP were expressed strong positively in chicken small intestinal mucosa epithelium, intestinal gland cell cavity surface, submucosal plexus and myenteric plexus; The expressions of GFAP were positive in the mucosal lamina propria and myenteric nerve plexus around the blood vessel; In avian escherichia sticky epithelial membrane, colorectal adenocarcinoma,GFAP were expressed positively, and the expressions were strong positive in mucosa epithelium, submucosal plexus and myenteric plexus. GFAP was one of the specific marker of enteric glial cells, and the observation of distribution of GFAP in chicken intestinal tract was help for elucidating the enteric glial cells in the distribution of the intestine and providing the morphological basis for the study of chicken glial cell function. 相似文献
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Morphologic structures of the lymphoid tissues associated with the mucosa of the respiratory tract in swine aged 11 to 13 weeks were studied by dissecting, light, and transmission electron microscopy. Tissues along the respiratory tract were collected for further examination. Light microscopic examination showed that the lymphoid tissues were associated with bronchi (8.38%), bronchioles (81.63%), and respiratory bronchioles (9.98%). The lymphoid tissues were identified at different levels of the airways and were designated intrapulmonary airway mucosa-associated lymphoid tissues. Anatomically, the lymphoid tissues were found mostly in the bronchiolar bifurcations, with an arteriole frequently nearby. Histologically, the lymphoid tissues contained a single dome-shaped lymphoid follicle, which bulged out from the mucosal surface into the airway, where it was covered along the mucosal side by a layer of specialized epithelium. Ultrastructurally, the mucosal surface of the specialized epithelial cells was equipped with microfolds or cytoplasmic projections instead of cilia. The cytoplasm was elongated, and therefore much thinner than that of ordinary epithelial cells. Many lymphocytes were found scattered in the mucosal epithelium between or beneath the specialized epithelial cells. This structure was similar to that seen in the Peyer's patches of the small intestine in swine and other animals. 相似文献
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Talukder MJ Takeuchi T Harada E 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2003,50(3):123-131
Several lines of evidence have recently demonstrated the occurrence of specific lactoferrin (Lf) receptors in different cells. We report here, for the first time, the characteristics of binding, and distribution of Lf receptors in the bovine intestinal tract with special emphasis on the epithelium overlying Peyer's patches (EOPP). Brush-border membrane vesicles (BBMV) were prepared from the mucosa of duodenum, jejunum, ileum, colon, EOPP in jejunum and EOPP in ileum. Receptor binding assays were carried out using 125I-labelled bovine Lf. Specific and saturable Lf receptors were found in BBMV of all the intestinal segments examined. Non-linear regression and Scatchard plot analyses clearly revealed that EOPP had the highest binding maximal (Bmax), and lowest in colon. The maximum dissociation constant (Kd) 3.74 microm was in the ileum. We found that bovine transferrin competed with Lf for the same binding site of receptors. In contrast, no binding of bovine serum albumin occurred. It was concluded that Lf receptors in the mucosal lining are attributable to mediate multifunctional activities of Lf in the gut, especially in the EOPP. 相似文献
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Adherence of Bordetella bronchiseptica and Pasteurella multocida to porcine nasal and tracheal epithelial cells. 总被引：4，自引：1，他引：3 
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下载免费PDF全文 The ability of 19 different Bordetella bronchiseptica isolates and 25 Pasteurella multocida isolates to adhere in vitro to porcine nasal and tracheal epithelial cells was examined. It was found that B. bronchiseptica adhered well to upper respiratory tract cells. In contrast the number of P. multocida organisms which adhered was four to six times less than the number of B. bronchiseptica adherent organisms. This difference was statistically significant (p less than 0.0001). Both microorganisms adhered in greater numbers to nasal cells than to tracheal cells (p less than 0.005). The data indicated that B. bronchiseptica possesses a greater ability than P. multocida to attach to porcine upper respiratory tract cells. 相似文献
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Vandekerckhove AP Glorieux S Gryspeerdt AC Steukers L Van Doorsselaere J Osterrieder N Van de Walle GR Nauwynck HJ 《Veterinary microbiology》2011,152(1-2):21-28
Equine herpesvirus type 1 (EHV-1) replicates extensively in the epithelium of the upper respiratory tract, after which it can spread throughout the body via a cell-associated viremia in mononuclear leukocytes reaching the pregnant uterus and central nervous system. In a previous study, we were able to mimic the in vivo situation in an in vitro respiratory mucosal explant system. A plaquewise spread of EHV-1 was observed in the epithelial cells, whereas in the connective tissue below the basement membrane (BM), EHV-1-infected mononuclear leukocytes were noticed. Equine herpesvirus type 4 (EHV-4), a close relative of EHV-1, can also cause mild respiratory disease, but a cell-associated viremia in leukocytes is scarce and secondary symptoms are rarely observed. Based on this striking difference in pathogenicity, we aimed to evaluate how EHV-4 behaves in equine mucosal explants. Upon inoculation of equine mucosal explants with the EHV-4 strains VLS 829, EQ(1) 012 and V01-3-13, replication of EHV-4 in epithelial cells was evidenced by the presence of viral plaques in the epithelium. Interestingly, EHV-4-infected mononuclear leukocytes in the connective tissue below the BM were extremely rare and were only present for one of the three strains. The inefficient capacity of EHV-4 to infect mononuclear cells explains in part the rarity of EHV-4-induced viremia, and subsequently, the rarity of EHV-4-induced abortion or EHM. 相似文献