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Amadori M Tagliabue S Lauzi S Finazzi G Lombardi G Teló P Pacciarini L Bonizzi L 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2002,49(2):89-96
Because of the frequent exposure of cattle to mycobacteria of the avium/intracellulare group, an investigation was carried out into the possible repercussions thereof on the diagnosis of bovine tuberculosis. Three calves from a bovine tuberculosis-free herd, scored avian reactors in the gamma-interferon assay for bovine tuberculosis, were sedated and inoculated endotracheally with a virulent Mycobacterium bovis strain. Then, three other avian reactors were housed with the above donor calves. Mycobacterium bovis was isolated from the nasal swabs of the three endotracheally infected, donor calves. On these samples, TB complex-specific polymerase chain reaction (PCR) tests for IS6110 were also positive, albeit with a different time kinetics. The three contact-infected calves showed clear immunological signs of infection; however, their nasal swabs were always PCR-negative and only Mycobacterium avium was isolated. In the endotracheally infected donor calves there was a rise of the gamma-interferon responses to avian and bovine purified protein derivative (PPD) tuberculins, which reached the same stable plateau levels over the whole experiment. The above effect was also observed in the contact-infected calves, even though the response to avian PPD tuberculin always remained at a higher level. By using conventional bovine and avian PPD tuberculins, the comparative intradermal test was generally positive in endotracheally infected, as opposed to contact-infected calves; a positive intradermal test for M. bovis was obtained in two contact-infected calves by different bovine PPD tuberculins based on M. bovis bacillus Calmette-Guerin (BCG) secreted or somatic antigens. It was concluded that M. bovis infection may be concealed for some time in cattle sensitized by mycobacteria of the avium/intracellulare group and that different diagnostic procedures should be adopted for such animals. 相似文献
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北京地区油松侧柏混交林树种间营养交互作用的矢量竞争分析(英文) 总被引：1，自引：0，他引：1
矢量竞争分析法是一种用于评价存在相同资源竞争的两种植物种之间的生长和营养交互作用的图形分析方法 .它基于矢量分析和线性分析 ,将代表生物量和营养吸收值的参数相对于无种间竞争的对照在一个两维的坐标系内表达为矢量并进行定位比较 .应用该方法对北京西山地区的 4 4年生人工混交林中油松和侧柏树种间生长和营养 (N ,P和K)吸收状况进行了比较和分析 .研究表明虽然混交有利于侧柏生物量的相对增加 ,但伴随有植物体内营养元素的相对亏缺 .相反 ,混交对油松生物量和高、径生长的抑制作用却伴随有营养元素吸收相对过剩 .以上结果表明矢量竞争分析可用于正确地揭示混交林树种之间营养交互作用 相似文献
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In order to assess the level of Rhodococcus equi infection in southeast Turkey, 679 sera from healthy foals and adult horses and 78 sera from donkeys were tested by indirect ELISA using a R. equi reference strain (ATCC 33701) as antigen. Eighty (11.7%) sera from horses and 9 (11.5%) sera from donkeys with titres >0.85 were positive. The prevalence of seropositive horses in Sanliurfa Province was higher than in Diyarbakir Province; 56 (13.9%) horses in Sanliurfa Province and 24 (8.7%) horses in Diyarbakir Province were defined as seropositive. In Sanliurfa Province 14.5% of female (n=343) and 10.1% of male (n = 59) horses tested were defined as seropositive, while in Diyarbakir Province more males (11.4%, n=114) were seropositive than females (6.7%, n=163). Horses 1 to 5 years of age were found to have the highest seropositivity rate in both provinces. A total of 78 sera from donkeys were investigated in Sanliurfa Province, of which 9 (11.5%) were positive by ELISA. Among the 9 positive sera, 6 (12.8%) were from donkeys 1-5 years old and 3 (13.6%) were from donkeys >5 years of age. No positive sera were found in donkeys less than 1 year old. Five (12.5%) sera of females and 4 (10.5%) sera of males tested were positive. These results indicate the existence of R. equi in the horse populations in Sanliurfa and Diyarbakir Provinces. Similar infection rates were found for donkeys in Sanliurfa. This suggests the importance of serological surveys to diagnose R. equi infection in the region and to prevent the zoonotic risk. 相似文献
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The unique ability of dried plant residues Azolla to adsorb iron (Fe) was employed to formulate and test an organic Fe biofertilizer. A simplified experimental system was established to examine the effectiveness of Fe‐enriched Azolla as a source of Fe for the remedy of Fe‐deficient plants. The optimal Fe‐enrichment level needed to achieve a complete recovery of starved plant by the Fe‐Azolla complex was tested using a bioassay system of hydroponically grown cucumbers. Dried Azolla plants were mixed a with a solution of ferrous sulfate (FeSO4) at pH 2.0, rinsed, and dried to form organic, compact material containing 4% (w/w) Fe bound to Azolla. The Fe‐Azolla complex was applied to the nutrient solutions of Fe‐deficient cucumber seedlings. Growth rates and development measurements as well as chlorophyll and the Fe‐containing catalase activity tests have been performed. The effect of the slowly released Fe in correcting Fe deficiency were followed for three weeks and compared with the efficiency of additions of several synthetic Fe chelates. Iron‐starved plants exhibited fast regreening of the chlorotic interveinal tissues after the addition of Fe‐Azolla complex to the nutrient solutions. Iron starvation decreased the activity of catalase. Iron‐treated‐starved plants exhibited recovery of catalase activity compared to the low level activity measured untreated Fe‐starved plants. Iron‐enriched Azolla treatment was found equivalent to Fe‐EDTA and Fe‐EDDHA. This study is the first step in our research program aimed to establish the application of Fe‐enriched Azolla as a bioagent for the benefit of Fe‐deficient crops. 相似文献
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In this study, Staphylococcus aureus strains (n = 110) isolated from seven ewe flocks in Sanliurfa, Turkey were screened for antibiotic resistance and biofilmforming ability as well as for genes associated with antibiotic resistance and biofilm-forming ability. All isolates were found to be susceptible to oxacillin, gentamicin, clindamycin, cefoxitin, tetracycline, vancomycin, amoxicillin-clavulanic acid, ciprofloxacin and sulphamethoxazole-trimethoprim. The percent proportions of strains resistant to penicillin G, ampicillin and erythromycin were 27.2% (n = 30), 25.4% (n = 28) and 6.3% (n = 7), respectively. Regarding the antibiotic resistance genes, 32 (29%) isolates carried the blaZ and 8 (7.2%) the ermC gene. Other resistance genes were not detected in the isolates. All isolates showed biofilm-forming ability on Congo red agar (CRA), while 108 (98.18%) and 101 (91.81%) of them were identified as biofilm producers by the use of standard tube (ST) and microplate (MP) methods, respectively. All isolates carried the icaA and icaD genes but none of them harboured the bap gene. The results demonstrated that S. aureus isolates from gangrenous mastitis were mainly resistant to penicillins (which are susceptible to the staphylococcal beta-lactamase enzyme), and less frequently to erythromycin. Furthermore, all of the S. aureus isolates produced biofilm which was considered a potential virulence factor in the pathogenesis of staphylococcal mastitis. 相似文献
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