Detection of leptospiral antigens in kidney and liver of cattle     

Sağlam YS  Temur A  Aslan A 《DTW. Deutsche tier?rztliche Wochenschrift》2003,110(2):75-77

This study was designed to investigate the presence of leptospiral antigens in kidney and liver of naturally infected cattle using an immunoperoxidase (IP) staining and Levaditi's staining methods. A total of 39 cattle suspected from leptospirosis were examined histologically and immunohistochemically for the presence of leptospiral antigens. The leptospiral antigens were detected in 16 out of 39 cases (seven kidneys, three livers, and six kidneys and livers) when IP staining method was used, whereas leptospiral antigens were detected in 6 out of 39 cases (four kidneys and two livers) when Levaditi's staining method was used. This study ascertained that IP staining was more sensitive method than Levaditi's staining method for demonstrating the presence of leptospirosis in cattle.  相似文献   

Resonant formation of DNA strand breaks by low-energy (3 to 20 eV) electrons     

Boudaïffa B  Cloutier P  Hunting D  Huels MA  Sanche L 《Science (New York, N.Y.)》2000,287(5458):1658-1660

Most of the energy deposited in cells by ionizing radiation is channeled into the production of abundant free secondary electrons with ballistic energies between 1 and 20 electron volts. Here it is shown that reactions of such electrons, even at energies well below ionization thresholds, induce substantial yields of single- and double-strand breaks in DNA, which are caused by rapid decays of transient molecular resonances localized on the DNA's basic components. This finding presents a fundamental challenge to the traditional notion that genotoxic damage by secondary electrons can only occur at energies above the onset of ionization, or upon solvation when they become a slowly reacting chemical species.  相似文献   

Passive protection of dogs against clinical disease due to Canine parvovirus-2 by specific antibody from chicken egg yolk   总被引：4，自引：0，他引：4       下载免费PDF全文

Sa Van Nguyen  Kouji Umeda  Hideaki Yokoyama  Yukinobu Tohya    Yoshikatsu Kodama 《Canadian journal of veterinary research》2006,70(1):62-64

The protective effect of immunoglobulins derived from chicken egg yolk (IgY) against infection by Canine parvovirus 2 (CPV-2) was evaluated in 10 beagle dogs orally challenged with a strain of the virus. The 2-mo-old dogs were divided into 3 groups and treated with powders containing CPV-2 IgY or normal egg yolk for 7 d after the challenge. The 4 dogs receiving normal egg yolk (control group) demonstrated mild symptoms typical of CPV-2 infection, such as vomiting, diarrhea, and weight loss. No symptoms were observed by 16 d after challenge in the 3 dogs receiving 2 g of IgY powder. Of the 3 dogs receiving 0.5 g of IgY powder, 2 had clinical CPV-2 disease; however, the manifestations were less severe than in the control group. Furthermore, the IgY-treated groups had significantly greater weight gain and shorter duration of virus shedding than the control group. These results indicate that IgY is useful in protecting dogs from CPV-2-induced clinical disease.  相似文献   

Artenspektrum und Befallshäufigkeit von Fusarium spp. in Bt- und konventionellem Mais im Maiszünsler-Befallsgebiet Oderbruch     

Matthias Saß  Markus Schorling  Monika Goßmann  Carmen Büttner 《Gesunde Pflanzen》2007,59(3):119-125

The European corn borer (Ostrinia nubilalis) is one of the most important pests of maize (Zea mays). Injuries to the plants caused by the larvae of the European corn borer may represent entrance gates for fungal-spores. The cultivation of Bacillus thuringiensis maize (Bt-maize) is one possibility to reduce infestation by the European corn borer. The aim of the present project was to determine and to compare the number of species and the frequency of Fusarium spp. infestation in Bt-maize (cry1Ab) and conventional maize. In 2003, we analysed the Fusarium spp. infestation of samples of chaffed Bt-maize and its isogenic variety on two experimental fields in the Oderbruch region (Germany), an European corn borer infested area. The conventional variety on the first of the experimental fields (previous crop wheat and forking cultivation) showed a small infestation (16%) of Ostrinia nubilalis while in the conventional variety on the second field (previous crop maize and not forking cultivation) the infestation of the European corn borer was almost three times higher (47%). In the conventional variety on both of the experimental fields we found a high Fusarium spp. infestation (70%). Especially species of the section Liseola dominates, among them: F. subglutinans, F. proliferatum und F. verticillioides. The Fusarium infestation in the samples of Bt-maize from the field with previous crop wheat and forking cultivation was just as high as in the conventional variety (70%). The infestation of Fusarium spp. in the samples of Bt-maize from the field with previous crop maize and forking cultivation was more than 20?% lower.  相似文献   

Effect of temperature on development,mortality, fecundity and reproduction of<Emphasis Type="Italic">Tuberolachnus salignus</Emphasis> on weeping willow (<Emphasis Type="Italic">Salix babylonica</Emphasis>) and corkscrew willow (<Emphasis Type="Italic">Salix matsudana</Emphasis>)     

N. Özder  Ö. Sağlam  A. Güven  V. Aydın 《Phytoparasitica》2007,35(4):386-391

The development time, survivorship and reproduction ofTuberolachnus salignus (Gmelin) (Hemiptera: Aphididae) [Lachninae, Lachnini] were studied onSalix babylonica (weeping willow) andSalix matsudana (corkscrew willow) at five constant temperatures (17.5, 20, 22.5, 25 and 27.5°C). The development time of immature stages ofT. salignus ranged from 14.56 days at 17.5°C to 12.50 days at 25°C onS. babylonica, and 16.47 days at 20°C to 12.28 days at 25°C onS. matsudana. The total survivorship of immature stages ofT. salignus varied from 28% to 85% at 22.5 and 17.5°C, respectively, onS. babylonica, and from 13% to 63%, respectively, at 17.5 and 25°C onS. matsudana. The greatest intrinsic rate of increase occurred at 25°C onS. babylonica (0.2691) and also onS. matsudana (0.2607). The mean generation time of the aphid population ranged from 14.15 days at 25°C to 16.24 days at 17.5°C onS. babylonica, and from 14.33°C days at 25°C to 19.86 days at 20°C onS. matsudana. The optimal temperature forS. babylonica growth, development time, reproduction and percent survival was 25°C.  相似文献   

Cell wall disassembly during papaya softening: Role of ethylene in changes in composition,pectin-derived oligomers (PDOs) production and wall hydrolases     

J. Adriana Sañudo-Barajas  John Labavitch  Carl Greve  Tomás Osuna-Enciso  Dolores Muy-Rangel  Jorge Siller-Cepeda 《Postharvest Biology and Technology》2009,51(2):158-167

Cell wall disassembly in ripening climacteric fruit is a highly complex process where ethylene plays a crucial role. Ethylene inhibitors can be used to explore the changes in the cell wall matrix and cross-linked polysaccharides in ethylene-regulated processes. The results of applying the ethylene receptor blocking inhibitor 1-methylcyclopropene (1-MCP) and the ethylene-releasing compound ethephon (2-chloroethylphosphonic acid) indicate that softening of ‘Maradol’ papaya fruit is dependent on ethylene. When fruit were induced to ripen extensively by exposure to a high dose of ethephon, 1-MCP inhibited the subsequent softening dramatically, but when inhibition of the ethylene response was caused by application of 1-MCP, subsequent fruit treatment with ethephon promoted extensive loss of galactose from the water-soluble polysaccharides, but this was not accompanied by fruit softening. The cell wall changes accompanying normal fruit softening were pectin solubilization and polyuronide depolymerization and these processes occurred simultaneously. Polygalacturonase likely is responsible for the ripening-associated changes in ‘Maradol’ papaya fruit texture and pectin polymer integrity. An increase in extractable fruit polygalacturonase follows the increased presence of pectin-derived oligosaccharides.  相似文献   

乡村园林景观规划存在的问题及设计要求   总被引：1，自引：0，他引：1  

李飒 《现代农业科技》2012,(13):205-207

总结了传统乡土园林的主要特点及景观范畴,分析了存在的问题,并提出设计要求,以期为乡村园林景观规划提供参考。  相似文献   

农业生产托管模式效率差异及其影响因素研究——以黑龙江省为例   总被引：1，自引：0，他引：1  

张梅  杨洒  颜华 《农业现代化研究》2022,43(3):484-492

农业生产托管是实现小农户与现代农业有机衔接的重要途径,但不同托管模式可能存在效率差异,探究不同托管模式的效率差异对农业现代化发展具有重要的现实意义。本文基于产权理论,以黑龙江省为例,利用农业生产托管组织的调查数据,运用超越对数随机前沿生产函数,分析不同农业生产托管模式的技术效率差异并探讨其影响因素。结果表明,农业生产托管分为村集体主导型和新型农业经营主体主导型两种模式,村集体主导模式与新型农业经营主体主导模式之间存在技术效率差异,村集体主导模式的平均技术效率比新型农业经营主体主导模式高7.79个百分点。农业生产托管规模、托管土地细碎化程度、托管组织自给劳动力人数、设置农业经纪人能显著影响农业生产托管的技术效率。村集体主导模式与新型农业经营主体主导模式效率差异原因在于村集体主导模式土地细碎化程度较低,且由于产权原因自给劳动力人数普遍较多,而新型农业经营主体主导模式没有充分发挥托管规模与农业经纪人优势。因此,提出积极鼓励发展村集体主导模式、进一步支持新型农业经营主体扩大托管规模、培育农业经纪人队伍等建议。  相似文献   

降水对内蒙古草原植被生长的影响     

滑永春  萨如拉  包文学 《东北林业大学学报》2021,49(7):47-55

为了解降水对草地植被生长的影响和草地植被变化的关键因子,以1982—2015年间内蒙古草地为研究对象,应用植被指数、降水和草地类型数据,采用皮尔逊相关系数和滞后系数方法,分析内蒙古地区不同草原类型归一化植被指数的降水滞后性.结果表明:(1)草地年降水量由大到小依次为:草甸草原(477.39 mm)、典型草原(391.52 mm)、荒漠草原(247.41 mm),草甸草原7月份降水量达到最大值,而荒漠草原8月份降水量达到最大.(2)草甸草原、典型草原、荒漠草原的归一化植被指数呈现单峰变化规律,荒漠草原的归一化植被指数变化不显著,整个生长季的归一化植被指数波动不大;不同草原类型的年均归一化植被指数值由大到小依次为:草甸草原(0.33)、典型草原(0.23)、荒漠草原(0.14).(3)生长季草原植被归一化植被指数与降水显著相关,草原植被生长对降水存在明显的滞后性,不同月份滞后时间存在差异.9月份草原植被生长对降水的滞后时间为2个月,5—8月份草原植被生长对降水的滞后时间为1个月左右,4月份草原植被生长对降水的滞后不明显.滞后月份降水和归一化植被指数相关系数和显著相关面积占比由大到小的顺序为:荒漠草原、典型草原、草甸草原.因此,归一化植被指数变化(草原植被生长)对降水存在明显的滞后性,可以有效预测牧草的长势和干旱情况.  相似文献   

Functional investigation of a QTL affecting resistance to Haemonchus contortus in sheep     

Guillaume Sallé  Carole Moreno  Simon Boitard  Julien Ruesche  Aurélie Tircazes-Secula  Frédéric Bouvier  Mathias Aletru  Jean-Louis Weisbecker  Fran?oise Prévot  Jean-Paul Bergeaud  Cathy Trumel  Christelle Grisez  Emmanuel Liénard  Philippe Jacquiet 《Veterinary research》2014,45(1):68

This study reports a functional characterization of a limited segment (QTL) of sheep chromosome 12 associated with resistance to the abomasal nematode Haemonchus contortus. The first objective was to validate the identified QTL through the comparison of genetically susceptible (N) and resistant (R) sheep produced from Martinik × Romane back-cross sheep. The R and N genotype groups were then experimentally infected with 10 000 H. contortus larvae and measured for FEC (every three days from 18 to 30 days post-challenge), haematocrit, worm burden and fertility. Significant differences in FEC and haematocrit drop were found between R and N sheep. In addition, the female worms recovered from R sheep were less fecund. The second step of the characterization was to investigate functional mechanisms associated with the QTL, thanks to a gene expression analysis performed on the abomasal mucosa and the abomasal lymph node. The gene expression level of a candidate gene lying within the QTL region (PAPP-A2) was measured. In addition, putative interactions between the chromosome segment under study and the top ten differentially expressed genes between resistant MBB and susceptible RMN sheep highlighted in a previous microarray experiment were investigated. We found an induction of Th-2 related cytokine genes expression in the abomasal mucosa of R sheep. Down-regulation of the PAPP-A2 gene expression was observed between naïve and challenged sheep although no differential expression was recorded between challenged R and N sheep. The genotyping of this limited region should contribute to the ability to predict the intrinsic resistance level of sheep.  相似文献